One of the minor protein components of skeletal muscle. Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.
One of the three polypeptide chains that make up the TROPONIN complex. It is a cardiac-specific protein that binds to TROPOMYOSIN. It is released from damaged or injured heart muscle cells (MYOCYTES, CARDIAC). Defects in the gene encoding troponin T result in FAMILIAL HYPERTROPHIC CARDIOMYOPATHY.
One of the three polypeptide chains that make up the TROPONIN complex of skeletal muscle. It is a calcium-binding protein.
A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
An isoenzyme of creatine kinase found in the CARDIAC MUSCLE.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
Contractile tissue that produces movement in animals.
A transferase that catalyzes formation of PHOSPHOCREATINE from ATP + CREATINE. The reaction stores ATP energy as phosphocreatine. Three cytoplasmic ISOENZYMES have been identified in human tissues: the MM type from SKELETAL MUSCLE, the MB type from myocardial tissue and the BB type from nervous tissue as well as a mitochondrial isoenzyme. Macro-creatine kinase refers to creatine kinase complexed with other serum proteins.
Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
Pressure, burning, or numbness in the chest.
A protein complex of actin and MYOSINS occurring in muscle. It is the essential contractile substance of muscle.
The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.
NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).
A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.
Contractile activity of the MYOCARDIUM.
General or unspecified injuries to the heart.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.
A form of CARDIAC MUSCLE disease, characterized by left and/or right ventricular hypertrophy (HYPERTROPHY, LEFT VENTRICULAR; HYPERTROPHY, RIGHT VENTRICULAR), frequent asymmetrical involvement of the HEART SEPTUM, and normal or reduced left ventricular volume. Risk factors include HYPERTENSION; AORTIC STENOSIS; and gene MUTATION; (FAMILIAL HYPERTROPHIC CARDIOMYOPATHY).
A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the Greek "psoa", the plural meaning "muscles of the loin". It is a common site of infection manifesting as abscess (PSOAS ABSCESS). The psoas muscles and their fibers are also used frequently in experiments in muscle physiology.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
A class of organic compounds that contains a naphthalene moiety linked to a sulfonic acid salt or ester.
Precordial pain at rest, which may precede a MYOCARDIAL INFARCTION.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Thiadiazines are heterocyclic compounds containing a 5-membered ring made up of two nitrogen atoms and three carbon atoms, one of which is bonded to a sulfur atom, and are known for their diverse pharmacological properties, including use as anti-inflammatory, anticonvulsant, and antipsychotic agents.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.
The hollow, muscular organ that maintains the circulation of the blood.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
An autosomal dominant inherited form of HYPERTROPHIC CARDIOMYOPATHY. It results from any of more than 50 mutations involving genes encoding contractile proteins such as VENTRICULAR MYOSINS; cardiac TROPONIN T; ALPHA-TROPOMYOSIN.
An episode of MYOCARDIAL ISCHEMIA that generally lasts longer than a transient anginal episode that ultimately may lead to MYOCARDIAL INFARCTION.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the CARDIAC MUSCLE and the SKELETAL MUSCLE.
A long-acting calcium-blocking agent with significant anti-anginal activity. The drug produces significant coronary vasodilation and modest peripheral effects. It has antihypertensive and selective anti-arrhythmia activities and acts as a calmodulin antagonist.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
Parts of the myosin molecule resulting from cleavage by proteolytic enzymes (PAPAIN; TRYPSIN; or CHYMOTRYPSIN) at well-localized regions. Study of these isolated fragments helps to delineate the functional roles of different parts of myosin. Two of the most common subfragments are myosin S-1 and myosin S-2. S-1 contains the heads of the heavy chains plus the light chains and S-2 contains part of the double-stranded, alpha-helical, heavy chain tail (myosin rod).
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A form of CARDIAC MUSCLE disease in which the ventricular walls are excessively rigid, impeding ventricular filling. It is marked by reduced diastolic volume of either or both ventricles but normal or nearly normal systolic function. It may be idiopathic or associated with other diseases (ENDOMYOCARDIAL FIBROSIS or AMYLOIDOSIS) causing interstitial fibrosis.
A disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. The decreased blood flow may be due to narrowing of the coronary arteries (CORONARY ARTERY DISEASE), to obstruction by a thrombus (CORONARY THROMBOSIS), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. Severe interruption of the blood supply to the myocardial tissue may result in necrosis of cardiac muscle (MYOCARDIAL INFARCTION).
A PEPTIDE that is secreted by the BRAIN and the HEART ATRIA, stored mainly in cardiac ventricular MYOCARDIUM. It can cause NATRIURESIS; DIURESIS; VASODILATION; and inhibits secretion of RENIN and ALDOSTERONE. It improves heart function. It contains 32 AMINO ACIDS.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Measurement of the intensity and quality of fluorescence.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.
A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance.
A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
Myosin type II isoforms found in cardiac muscle.
A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.
An element of the alkaline earth family of metals. It has the atomic symbol Sr, atomic number 38, and atomic weight 87.62.
The rate dynamics in chemical or physical systems.
A large family of mollusks in the class BIVALVIA, known commonly as scallops. They possess flat, almost circular shells and are found in all seas from shallow water to great depths.
Disease having a short and relatively severe course.
Elements of limited time intervals, contributing to particular results or situations.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Laboratory tests demonstrating the presence of physiologically significant substances in the blood, urine, tissue, and body fluids with application to the diagnosis or therapy of disease.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).
A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.
A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, VENTRICULAR DYSFUNCTION, and HEART FAILURE. Risk factors include SMOKING; ALCOHOL DRINKING; HYPERTENSION; INFECTION; PREGNANCY; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.
Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
The determination of the concentration of a given component in solution (the analyte) by addition of a liquid reagent of known strength (the titrant) until an equivalence point is reached (when the reactants are present in stoichiometric proportions). Often an indicator is added to make the equivalence point visible (e.g., a change in color).
Pathological conditions involving the HEART including its structural and functional abnormalities.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
A phylum of the kingdom Metazoa. Mollusca have soft, unsegmented bodies with an anterior head, a dorsal visceral mass, and a ventral foot. Most are encased in a protective calcareous shell. It includes the classes GASTROPODA; BIVALVIA; CEPHALOPODA; Aplacophora; Scaphopoda; Polyplacophora; and Monoplacophora.
Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.
Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.
Proteins prepared by recombinant DNA technology.
Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.

Properties of non-polymerizable tropomyosin obtained by carboxypeptidase A digestion. (1/1215)

Tropomyosin digested with carboxypeptidase A [EC] (CTM) shows a lower viscosity than the undigested protein in solution. From the relation between the viscosity decrease and the amount of amino acids liberated from the carboxyl terminus during this digestion, it is inferred that loss of the tri-peptide-Thr-Ser-Ile from the C-terminus is responsible for the decrease in viscosity. The secondary structure of -TM was not affected by the digestion according to circular dichroic measurements. The viscosity of CTM did not increase in methanol-water mixtures, whereas that of tropomyosin increased markedly. These results indicate that polymerizability was lost upon the removal of a small peptide from the C-terminus without change in the secondary structure. A decrease in the viscosity of tropomyosin solutions was observed on the addition of CTM, indicating that CTM interacts with intact tropomyosin. The dependence of the viscosity decrease on the amount of CTM showed that CTM binds tropomyosin in a one-to-one ratio as a result of end-to-end interaction. Since paracrystals having a 400 A repeated band structure could be grown in the presence of Mg ions at neutral pH, side-by-side interactions in CTM molecules remain intact, even though polymerizability is lost. The disc gel electrophoretic pattern showed that troponin could bind to CTM, but no increase in viscosity due to the complex was observed in solution. That is, the C-terminal part of tropomyosin is not required for the formation of the complex. The amount of CTM bound to F-actin was less than half of that bound to undigested tropomyosin, and could be reduced to one-tenth by a washing procedure. In the presence of troponin, however, the amount recovered to the level of tropomyosin normally bound to F-actin. Therefore, it is concluded that troponin is bound in the middle of the tropomyosin molecule and strengthens the binding of tropomyosin to F-actin.  (+info)

Ca2+ and cross-bridge-induced changes in troponin C in skinned skeletal muscle fibers: effects of force inhibition. (2/1215)

Changes in skeletal troponin C (sTnC) structure during thin filament activation by Ca2+ and strongly bound cross-bridge states were monitored by measuring the linear dichroism of the 5' isomer of iodoacetamidotetramethylrhodamine (5'IATR), attached to Cys98 (sTnC-5'ATR), in sTnC-5'ATR reconstituted single skinned fibers from rabbit psoas muscle. To isolate the effects of Ca2+ and cross-bridge binding on sTnC structure, maximum Ca2+-activated force was inhibited with 0.5 mM AlF4- or with 30 mM 2,3 butanedione-monoxime (BDM) during measurements of the Ca2+ dependence of force and dichroism. Dichroism was 0.08 +/- 0.01 (+/- SEM, n = 9) in relaxing solution (pCa 9.2) and decreased to 0.004 +/- 0.002 (+/- SEM, n = 9) at pCa 4.0. Force and dichroism had similar Ca2+ sensitivities. Force inhibition with BDM caused no change in the amplitude and Ca2+ sensitivity of dichroism. Similarly, inhibition of force at pCa 4.0 with 0.5 mM AlF4- decreased force to 0.04 +/- 0.01 of maximum (+/- SEM, n = 3), and dichroism was 0.04 +/- 0.03 (+/- SEM, n = 3) of the value at pCa 9.2 and unchanged relative to the corresponding normalized value at pCa 4.0 (0.11 +/- 0.05, +/- SEM; n = 3). Inhibition of force with AlF4- also had no effect when sTnC structure was monitored by labeling with either 5-dimethylamino-1-napthalenylsulfonylaziridine (DANZ) or 4-(N-(iodoacetoxy)ethyl-N-methyl)amino-7-nitrobenz-2-oxa-1,3-diazole (NBD). Increasing sarcomere length from 2.5 to 3.6 microm caused force (pCa 4.0) to decrease, but had no effect on dichroism. In contrast, rigor cross-bridge attachment caused dichroism at pCa 9.2 to decrease to 0.56 +/- 0.03 (+/- SEM, n = 5) of the value at pCa 9. 2, and force was 0.51 +/- 0.04 (+/- SEM, n = 6) of pCa 4.0 control. At pCa 4.0 in rigor, dichroism decreased further to 0.19 +/- 0.03 (+/- SEM, n = 6), slightly above the pCa 4.0 control level; force was 0.66 +/- 0.04 of pCa 4.0 control. These results indicate that cross-bridge binding in the rigor state alters sTnC structure, whereas cycling cross-bridges have little influence at either submaximum or maximum activating [Ca2+].  (+info)

Amphidinolide B, a powerful activator of actomyosin ATPase enhances skeletal muscle contraction. (3/1215)

Amphidinolide B caused a concentration-dependent increase in the contractile force of skeletal muscle skinned fibers. The concentration-contractile response curve for external Ca2+ was shifted to the left in a parallel manner, suggesting an increase in Ca2+ sensitivity. Amphidinolide B stimulated the superprecipitation of natural actomyosin. The maximum response of natural actomyosin to Ca2+ in superprecipitation was enhanced by it. Amphidinolide B increased the ATPase activity of myofibrils and natural actomyosin. The ATPase activity of actomyosin reconstituted from actin and myosin was enhanced in a concentration-dependent manner in the presence or absence of troponin-tropomyosin complex. Ca2+-, K+-EDTA- or Mg2+-ATPase of myosin was not affected by amphidinolide B. These results suggest that amphidinolide B enhances an interaction of actin and myosin directly and increases Ca2+ sensitivity of the contractile apparatus mediated through troponin-tropomyosin system, resulting in an increase in the ATPase activity of actomyosin and thus enhances the contractile response of myofilament.  (+info)

The amino acid sequence of rabbit cardiac troponin I. (4/1215)

The complete amino acid sequence of troponin I from rabbit cardiac muscle was determined by the isolation of four unique CNBr fragments, together with overlapping tryptic peptides containing radioactive methionine residues. Overlap data for residues 35-36, 93-94 and 140-145 are incomplete, the sequence at these positions being based on homology with the sequence of the fast-skeletal-muscle protein. Cardiac troponin I is a single polypeptide chain of 206 residues with mol.wt. 23550 and an extinction coefficient, E 1%,1cm/280, of 4.37. The protein has a net positive charge of 14 and is thus somewhat more basic than troponin I from fast-skeletal muscle. Comparison of the sequences of troponin I from cardiac and fast skeletal muscle show that the cardiac protein has 26 extra residues at the N-terminus which account for the larger size of the protein. In the remainder of sequence there is a considerable degree of homology, this being greater in the C-terminal two-thirds of the molecule. The region in the cardiac protein corresponding to the peptide with inhibitory activity from the fast-skeletal-muscle protein is very similar and it seems unlikely that this is the cause of the difference in inhibitory activity between the two proteins. The region responsible for binding troponin C, however, possesses a lower degree of homology. Detailed evidence on which the sequence is based has been deposited as Supplementary Publication SUP 50072 (20 pages), at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7QB, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1976) 153, 5.  (+info)

Aldolase binding to actin-containing filaments. Formation of paracrystals. (5/1215)

Electron-microscopy observation show that when aldolase binds to F-actin or F-actin-tropomyosin, highly ordered paracrystalline structures are formed consisting of tightly packed filament bundles cross-banded at 36 nm intervals. Morphologically different paracrystalline arrays are formed between aldolase and F-actin-tropomyosin-troponin. The filament bundles are far more extensive and are characterized by a prominent cross-striation at 38nm intervals. It is suggested that this reflects an interaction between troponin and aldolase.  (+info)

Parvalbumin from rabbit muscle. Isolation and primary structure. (6/1215)

A parvalbumin, with its characteristic low molecular weight (approximately 12000) acidic isoelectric point (approximately 5.5), ultraviolet spectrum (maxm 259 nm) and Ca2+-binding capacity (2 mol/mol protein) has been isolated from rabbit (Oryctolagus cuniculus) muscle. Its primary structure has been determined from a study of its tryptic peptides and of overlapping peptides generated by limited tryptic digestion and by chymotryptic and thermolytic digestions of the protein. The amino acid sequence so obtained is considered in comparison with those known for other parvalbumin and for rabbit troponin C.  (+info)

Characterization of the cardiac holotroponin complex reconstituted from native cardiac troponin T and recombinant I and C. (7/1215)

Cardiac troponin I (cTnI), the inhibitory subunit of cardiac troponin (cTn), is phosphorylated by the cAMP-dependent protein kinase A at two adjacently located serine residues within the heart-specific N-terminal elongation. Four different phosphorylation states can be formed. To investigate each monophosphorylated form cTnI mutants, in which each of the two serine residues is replaced by an alanine, were generated. These mutants, as well as the wild-type cardiac troponin I (cTnI-WT) have been expressed in Escherichia coli, purified and characterized by isoelectric focusing, MS and CD-spectroscopy. Monophosphorylation induces conformational changes within cTnI that are different from those induced by bisphosphorylation. Functionality was assessed by measuring the calcium dependence of myosin S1 binding to thin filaments containing reconstituted native, wild-type and mutant cTn complexes. In all cases a functional holotroponin complex was obtained. Upon bisphosphorylation of cTnI-WT the pCa curve was shifted to the right to the same extent as that observed with bisphosphosphorylated native cTnI. However, the absolute values for the midpoints were higher when recombinant cTn subunits were used for reconstitution. Reconstitution itself changed the calcium affinity of cTnC: pCa50-values were higher than those obtained with the native cardiac holotroponin complex. Apparently only bisphosphorylation of cTnI influences the calcium sensitivity of the thin filament, thus monophosphorylation has a function different from that of bisphosphorylation; this function has not yet been identified.  (+info)

Comparison of putative cooperative mechanisms in cardiac muscle: length dependence and dynamic responses. (8/1215)

Length-dependent steady-state and dynamic responses of five models of isometric force generation in cardiac myofilaments were compared with similar experimental data from the literature. The models were constructed by assuming different subsets of three putative cooperative mechanisms. Cooperative mechanism 1 holds that cross-bridge binding increases the affinity of troponin for Ca2+. In the models, cooperative mechanism 1 can produce steep force-Ca2+ (F-Ca) relations, but apparent cooperativity is highest at midlevel Ca2+ concentrations. During twitches, cooperative mechanism 1 has the effect of increasing latency to peak as the magnitude of force increases, an effect not seen experimentally. Cooperative mechanism 2 holds that the binding of a cross bridge increases the rate of formation of neighboring cross bridges and that multiple cross bridges can maintain activation of the thin filament in the absence of Ca2+. Only cooperative mechanism 2 can produce sarcomere length (SL)-dependent prolongation of twitches, but this mechanism has little effect on steady-state F-Ca relations. Cooperativity mechanism 3 is designed to simulate end-to-end interactions between adjacent troponin and tropomyosin. This mechanism can produce steep F-Ca relations with appropriate SL-dependent changes in Ca2+ sensitivity. With the assumption that tropomyosin shifting is faster than cross-bridge cycling, cooperative mechanism 3 produces twitches where latency to peak is independent of the magnitude of force, as seen experimentally.  (+info)

Troponin is a protein complex found in cardiac and skeletal muscle cells that plays a critical role in muscle contraction. It consists of three subunits: troponin C, which binds calcium ions; troponin I, which inhibits the interaction between actin and myosin in the absence of calcium; and troponin T, which binds to tropomyosin and helps anchor the complex to the muscle filament.

In clinical medicine, "troponin" usually refers to cardiac-specific isoforms of these proteins (cTnI and cTnT) that are released into the bloodstream following damage to the heart muscle, such as occurs in myocardial infarction (heart attack). Measurement of troponin levels in the blood is a sensitive and specific biomarker for the diagnosis of acute myocardial infarction.

Troponin T is a subunit of the troponin complex, which is a protein complex that plays a crucial role in muscle contraction. In particular, Troponin T is responsible for binding the troponin complex to tropomyosin, another protein that helps regulate muscle contraction.

In the context of medical diagnostics, Troponin T is often measured as a biomarker for heart damage. When heart muscle cells are damaged or die, such as in a myocardial infarction (heart attack), troponin T is released into the bloodstream. Therefore, measuring the levels of Troponin T in the blood can help diagnose and assess the severity of heart damage.

It's important to note that Troponin T is specific to cardiac muscle cells, which makes it a more reliable biomarker for heart damage than other markers that may also be found in skeletal muscle cells. However, it's worth noting that Troponin T levels can also be elevated in conditions other than heart attacks, such as heart failure, myocarditis, and pulmonary embolism, so clinical context is important when interpreting test results.

Troponin C is a subunit of the troponin complex, which is a protein complex that plays a crucial role in muscle contraction. In the heart, the troponin complex is found in the myofibrils of cardiac muscle cells (cardiomyocytes). It is composed of three subunits: troponin C, troponin T, and troponin I.

Troponin C has the ability to bind calcium ions (Ca²+), which is essential for muscle contraction. When Ca²+ binds to troponin C, it causes a conformational change that leads to the exposure of binding sites on troponin I for another protein called actin. This interaction allows for the cross-bridge formation between actin and myosin, generating the force needed for muscle contraction.

In clinical settings, cardiac troponins (including troponin T and troponin I) are commonly measured in blood tests to diagnose and monitor heart damage, particularly in conditions like myocardial infarction (heart attack). However, Troponin C is not typically used as a biomarker for heart injury because it is less specific to the heart than troponin T and troponin I. Increased levels of Troponin C in the blood can be found in various conditions involving muscle damage or disease, making it less useful for diagnosing heart-specific issues.

Tropomyosin is a protein that plays a crucial role in muscle contraction. It is a long, thin filamentous protein that runs along the length of actin filaments in muscle cells, forming part of the troponin-tropomyosin complex. This complex regulates the interaction between actin and myosin, which are the other two key proteins involved in muscle contraction.

In a relaxed muscle, tropomyosin blocks the myosin-binding sites on actin, preventing muscle contraction from occurring. When a signal is received to contract, calcium ions are released into the muscle cell, which binds to troponin and causes a conformational change that moves tropomyosin out of the way, exposing the myosin-binding sites on actin. This allows myosin to bind to actin and generate force, leading to muscle contraction.

Tropomyosin is composed of two alpha-helical chains that wind around each other in a coiled-coil structure. There are several isoforms of tropomyosin found in different types of muscle cells, including skeletal, cardiac, and smooth muscle. Mutations in the genes encoding tropomyosin have been associated with various inherited muscle disorders, such as hypertrophic cardiomyopathy and distal arthrogryposis.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

Myofibrils are the basic contractile units of muscle fibers, composed of highly organized arrays of thick and thin filaments. They are responsible for generating the force necessary for muscle contraction. The thick filaments are primarily made up of the protein myosin, while the thin filaments are mainly composed of actin. Myofibrils are surrounded by a membrane called the sarcolemma and are organized into repeating sections called sarcomeres, which are the functional units of muscle contraction.

A biological marker, often referred to as a biomarker, is a measurable indicator that reflects the presence or severity of a disease state, or a response to a therapeutic intervention. Biomarkers can be found in various materials such as blood, tissues, or bodily fluids, and they can take many forms, including molecular, histologic, radiographic, or physiological measurements.

In the context of medical research and clinical practice, biomarkers are used for a variety of purposes, such as:

1. Diagnosis: Biomarkers can help diagnose a disease by indicating the presence or absence of a particular condition. For example, prostate-specific antigen (PSA) is a biomarker used to detect prostate cancer.
2. Monitoring: Biomarkers can be used to monitor the progression or regression of a disease over time. For instance, hemoglobin A1c (HbA1c) levels are monitored in diabetes patients to assess long-term blood glucose control.
3. Predicting: Biomarkers can help predict the likelihood of developing a particular disease or the risk of a negative outcome. For example, the presence of certain genetic mutations can indicate an increased risk for breast cancer.
4. Response to treatment: Biomarkers can be used to evaluate the effectiveness of a specific treatment by measuring changes in the biomarker levels before and after the intervention. This is particularly useful in personalized medicine, where treatments are tailored to individual patients based on their unique biomarker profiles.

It's important to note that for a biomarker to be considered clinically valid and useful, it must undergo rigorous validation through well-designed studies, including demonstrating sensitivity, specificity, reproducibility, and clinical relevance.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

Creatine kinase (CK) is an enzyme found in various cells throughout the body, including heart muscle cells and skeletal muscle fibers. The CK enzyme exists in different forms, depending on the type of tissue where it is found. One such form is creatine kinase MB (CK-MB), which is primarily found in cardiac muscle cells.

An increase in the levels of CK-MB in the blood can indicate damage to the heart muscle, such as that caused by a heart attack or myocardial infarction. When heart muscle cells are damaged, they release their contents, including CK-MB, into the bloodstream. Therefore, measuring CK-MB levels is a useful diagnostic tool for detecting and monitoring heart muscle damage.

It's important to note that while an elevated CK-MB level can suggest heart muscle damage, it is not specific to the heart and can also be elevated in other conditions such as skeletal muscle damage or certain muscle disorders. Therefore, CK-MB levels should be interpreted in conjunction with other clinical findings and diagnostic tests.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

Creatine kinase (CK) is a muscle enzyme that is normally present in small amounts in the blood. It is primarily found in tissues that require a lot of energy, such as the heart, brain, and skeletal muscles. When these tissues are damaged or injured, CK is released into the bloodstream, causing the levels to rise.

Creatine kinase exists in several forms, known as isoenzymes, which can be measured in the blood to help identify the location of tissue damage. The three main isoenzymes are:

1. CK-MM: Found primarily in skeletal muscle
2. CK-MB: Found primarily in heart muscle
3. CK-BB: Found primarily in the brain

Elevated levels of creatine kinase, particularly CK-MB, can indicate damage to the heart muscle, such as occurs with a heart attack. Similarly, elevated levels of CK-BB may suggest brain injury or disease. Overall, measuring creatine kinase levels is a useful diagnostic tool for assessing tissue damage and determining the severity of injuries or illnesses.

The actin cytoskeleton is a complex, dynamic network of filamentous (threadlike) proteins that provides structural support and shape to cells, allows for cell movement and division, and plays a role in intracellular transport. Actin filaments are composed of actin monomers that polymerize to form long, thin fibers. These filaments can be organized into different structures, such as stress fibers, which provide tension and support, or lamellipodia and filopodia, which are involved in cell motility. The actin cytoskeleton is constantly remodeling in response to various intracellular and extracellular signals, allowing for changes in cell shape and behavior.

Muscle proteins are a type of protein that are found in muscle tissue and are responsible for providing structure, strength, and functionality to muscles. The two major types of muscle proteins are:

1. Contractile proteins: These include actin and myosin, which are responsible for the contraction and relaxation of muscles. They work together to cause muscle movement by sliding along each other and shortening the muscle fibers.
2. Structural proteins: These include titin, nebulin, and desmin, which provide structural support and stability to muscle fibers. Titin is the largest protein in the human body and acts as a molecular spring that helps maintain the integrity of the sarcomere (the basic unit of muscle contraction). Nebulin helps regulate the length of the sarcomere, while desmin forms a network of filaments that connects adjacent muscle fibers together.

Overall, muscle proteins play a critical role in maintaining muscle health and function, and their dysregulation can lead to various muscle-related disorders such as muscular dystrophy, myopathies, and sarcopenia.

Chest pain is a discomfort or pain that you feel in the chest area. The pain can be sharp, dull, burning, crushing, heaviness, or tightness. It may be accompanied by other symptoms such as shortness of breath, sweating, nausea, dizziness, or pain that radiates to the arm, neck, jaw, or back.

Chest pain can have many possible causes, including heart-related conditions such as angina or a heart attack, lung conditions such as pneumonia or pleurisy, gastrointestinal problems such as acid reflux or gastritis, musculoskeletal issues such as costochondritis or muscle strain, and anxiety or panic attacks.

It is important to seek immediate medical attention if you experience chest pain that is severe, persistent, or accompanied by other concerning symptoms, as it may be a sign of a serious medical condition. A healthcare professional can evaluate your symptoms, perform tests, and provide appropriate treatment.

Actomyosin is a contractile protein complex that consists of actin and myosin filaments. It plays an essential role in muscle contraction, cell motility, and cytokinesis (the process of cell division where the cytoplasm is divided into two daughter cells). The interaction between actin and myosin generates force and movement through a mechanism called sliding filament theory. In this process, myosin heads bind to actin filaments and then undergo a power stroke, which results in the sliding of one filament relative to the other and ultimately leads to muscle contraction or cellular movements. Actomyosin complexes are also involved in various non-muscle cellular processes such as cytoplasmic streaming, intracellular transport, and maintenance of cell shape.

A sarcomere is the basic contractile unit in a muscle fiber, and it's responsible for generating the force necessary for muscle contraction. It is composed of several proteins, including actin and myosin, which slide past each other to shorten the sarcomere during contraction. The sarcomere extends from one Z-line to the next in a muscle fiber, and it is delimited by the Z-discs where actin filaments are anchored. Sarcomeres play a crucial role in the functioning of skeletal, cardiac, and smooth muscles.

Myocardial infarction (MI), also known as a heart attack, is a medical condition characterized by the death of a segment of heart muscle (myocardium) due to the interruption of its blood supply. This interruption is most commonly caused by the blockage of a coronary artery by a blood clot formed on the top of an atherosclerotic plaque, which is a buildup of cholesterol and other substances in the inner lining of the artery.

The lack of oxygen and nutrients supply to the heart muscle tissue results in damage or death of the cardiac cells, causing the affected area to become necrotic. The extent and severity of the MI depend on the size of the affected area, the duration of the occlusion, and the presence of collateral circulation.

Symptoms of a myocardial infarction may include chest pain or discomfort, shortness of breath, nausea, lightheadedness, and sweating. Immediate medical attention is necessary to restore blood flow to the affected area and prevent further damage to the heart muscle. Treatment options for MI include medications, such as thrombolytics, antiplatelet agents, and pain relievers, as well as procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

Myosins are a large family of motor proteins that play a crucial role in various cellular processes, including muscle contraction and intracellular transport. They consist of heavy chains, which contain the motor domain responsible for generating force and motion, and light chains, which regulate the activity of the myosin. Based on their structural and functional differences, myosins are classified into over 35 classes, with classes II, V, and VI being the most well-studied.

Class II myosins, also known as conventional myosins, are responsible for muscle contraction in skeletal, cardiac, and smooth muscles. They form filaments called thick filaments, which interact with actin filaments to generate force and movement during muscle contraction.

Class V myosins, also known as unconventional myosins, are involved in intracellular transport and organelle positioning. They have a long tail that can bind to various cargoes, such as vesicles, mitochondria, and nuclei, and a motor domain that moves along actin filaments to transport the cargoes to their destinations.

Class VI myosins are also unconventional myosins involved in intracellular transport and organelle positioning. They have two heads connected by a coiled-coil tail, which can bind to various cargoes. Class VI myosins move along actin filaments in a unique hand-over-hand motion, allowing them to transport their cargoes efficiently.

Overall, myosins are essential for many cellular functions and have been implicated in various diseases, including cardiovascular diseases, neurological disorders, and cancer.

Myocardial contraction refers to the rhythmic and forceful shortening of heart muscle cells (myocytes) in the myocardium, which is the muscular wall of the heart. This process is initiated by electrical signals generated by the sinoatrial node, causing a wave of depolarization that spreads throughout the heart.

During myocardial contraction, calcium ions flow into the myocytes, triggering the interaction between actin and myosin filaments, which are the contractile proteins in the muscle cells. This interaction causes the myofilaments to slide past each other, resulting in the shortening of the sarcomeres (the functional units of muscle contraction) and ultimately leading to the contraction of the heart muscle.

Myocardial contraction is essential for pumping blood throughout the body and maintaining adequate circulation to vital organs. Any impairment in myocardial contractility can lead to various cardiac disorders, such as heart failure, cardiomyopathy, and arrhythmias.

Heart injuries, also known as cardiac injuries, refer to any damage or harm caused to the heart muscle, valves, or surrounding structures. This can result from various causes such as blunt trauma (e.g., car accidents, falls), penetrating trauma (e.g., gunshot wounds, stabbing), or medical conditions like heart attacks (myocardial infarction) and infections (e.g., myocarditis, endocarditis).

Some common types of heart injuries include:

1. Contusions: Bruising of the heart muscle due to blunt trauma.
2. Myocardial infarctions: Damage to the heart muscle caused by insufficient blood supply, often due to blocked coronary arteries.
3. Cardiac rupture: A rare but life-threatening condition where the heart muscle tears or breaks open, usually resulting from severe trauma or complications from a myocardial infarction.
4. Valvular damage: Disruption of the heart valves' function due to injury or infection, leading to leakage (regurgitation) or narrowing (stenosis).
5. Pericardial injuries: Damage to the pericardium, the sac surrounding the heart, which can result in fluid accumulation (pericardial effusion), inflammation (pericarditis), or tamponade (compression of the heart by excess fluid).
6. Arrhythmias: Irregular heart rhythms caused by damage to the heart's electrical conduction system.

Timely diagnosis and appropriate treatment are crucial for managing heart injuries, as they can lead to severe complications or even be fatal if left untreated.

Actin is a type of protein that forms part of the contractile apparatus in muscle cells, and is also found in various other cell types. It is a globular protein that polymerizes to form long filaments, which are important for many cellular processes such as cell division, cell motility, and the maintenance of cell shape. In muscle cells, actin filaments interact with another type of protein called myosin to enable muscle contraction. Actins can be further divided into different subtypes, including alpha-actin, beta-actin, and gamma-actin, which have distinct functions and expression patterns in the body.

"Chickens" is a common term used to refer to the domesticated bird, Gallus gallus domesticus, which is widely raised for its eggs and meat. However, in medical terms, "chickens" is not a standard term with a specific definition. If you have any specific medical concern or question related to chickens, such as food safety or allergies, please provide more details so I can give a more accurate answer.

Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by the thickening of the heart muscle, specifically the ventricles (the lower chambers of the heart that pump blood out to the body). This thickening can make it harder for the heart to pump blood effectively, which can lead to symptoms such as shortness of breath, chest pain, and fatigue. In some cases, HCM can also cause abnormal heart rhythms (arrhythmias) and may increase the risk of sudden cardiac death.

The thickening of the heart muscle in HCM is caused by an overgrowth of the cells that make up the heart muscle, known as cardiomyocytes. This overgrowth can be caused by mutations in any one of several genes that encode proteins involved in the structure and function of the heart muscle. These genetic mutations are usually inherited from a parent, but they can also occur spontaneously in an individual with no family history of the disorder.

HCM is typically diagnosed using echocardiography (a type of ultrasound that uses sound waves to create images of the heart) and other diagnostic tests such as electrocardiogram (ECG) and cardiac magnetic resonance imaging (MRI). Treatment for HCM may include medications to help manage symptoms, lifestyle modifications, and in some cases, surgical procedures or implantable devices to help prevent or treat arrhythmias.

The psoas muscles are a pair of muscles that are located in the lower lumbar region of the spine and run through the pelvis to attach to the femur (thigh bone). They are deep muscles, meaning they are located close to the body's core, and are surrounded by other muscles, bones, and organs.

The psoas muscles are composed of two separate muscles: the psoas major and the psoas minor. The psoas major is the larger of the two muscles and originates from the lumbar vertebrae (T12 to L5) and runs through the pelvis to attach to the lesser trochanter of the femur. The psoas minor, which is smaller and tends to be absent in some people, originates from the lower thoracic vertebrae (T12) and upper lumbar vertebrae (L1-L3) and runs down to attach to the iliac fascia and the pectineal line of the pubis.

The primary function of the psoas muscles is to flex the hip joint, which means they help to bring the knee towards the chest. They also play a role in stabilizing the lumbar spine and pelvis during movement. Tightness or weakness in the psoas muscles can contribute to lower back pain, postural issues, and difficulty with mobility and stability.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

Naphthalenesulfonates are a group of chemical compounds that consist of a naphthalene ring, which is a bicyclic aromatic hydrocarbon, substituted with one or more sulfonate groups. Sulfonates are salts or esters of sulfuric acid. Naphthalenesulfonates are commonly used as detergents, dyes, and research chemicals.

In the medical field, naphthalenesulfonates may be used in diagnostic tests to detect certain enzyme activities or metabolic disorders. For example, 1-naphthyl sulfate is a substrate for the enzyme arylsulfatase A, which is deficient in individuals with the genetic disorder metachromatic leukodystrophy. By measuring the activity of this enzyme using 1-naphthyl sulfate as a substrate, doctors can diagnose or monitor the progression of this disease.

It's worth noting that some naphthalenesulfonates have been found to have potential health hazards and environmental concerns. For instance, sodium naphthalenesulfonate has been classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC). Therefore, their use should be handled with caution and in accordance with established safety protocols.

Unstable angina is a term used in cardiology to describe chest pain or discomfort that occurs suddenly and unexpectedly, often at rest or with minimal physical exertion. It is caused by an insufficient supply of oxygen-rich blood to the heart muscle due to reduced blood flow, typically as a result of partial or complete blockage of the coronary arteries.

Unlike stable angina, which tends to occur predictably during physical activity and can be relieved with rest or nitroglycerin, unstable angina is more severe, unpredictable, and may not respond to traditional treatments. It is considered a medical emergency because it can be a sign of an impending heart attack or other serious cardiac event.

Unstable angina is often treated in the hospital with medications such as nitroglycerin, beta blockers, calcium channel blockers, and antiplatelet agents to improve blood flow to the heart and prevent further complications. In some cases, more invasive treatments such as coronary angioplasty or bypass surgery may be necessary to restore blood flow to the affected areas of the heart.

A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.

Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.

Thiadiazines are a class of heterocyclic compounds containing a five-membered ring with two nitrogen atoms and two sulfur atoms. In the context of pharmaceuticals, thiadiazine derivatives are commonly used as therapeutic agents, particularly in the treatment of various cardiovascular diseases.

The most well-known thiadiazine derivative is hydrochlorothiazide, which is a diuretic drug used to treat hypertension and edema associated with heart failure, liver cirrhosis, and kidney disease. Hydrochlorothiazide works by inhibiting the reabsorption of sodium and chloride ions in the distal convoluted tubule of the nephron, thereby increasing water excretion and reducing blood volume and pressure.

Other thiadiazine derivatives have been investigated for their potential therapeutic benefits, including anti-inflammatory, anticonvulsant, and antimicrobial activities. However, many of these compounds have not yet been approved for clinical use due to safety concerns or lack of efficacy.

Electrocardiography (ECG or EKG) is a medical procedure that records the electrical activity of the heart. It provides a graphic representation of the electrical changes that occur during each heartbeat. The resulting tracing, called an electrocardiogram, can reveal information about the heart's rate and rhythm, as well as any damage to its cells or abnormalities in its conduction system.

During an ECG, small electrodes are placed on the skin of the chest, arms, and legs. These electrodes detect the electrical signals produced by the heart and transmit them to a machine that amplifies and records them. The procedure is non-invasive, painless, and quick, usually taking only a few minutes.

ECGs are commonly used to diagnose and monitor various heart conditions, including arrhythmias, coronary artery disease, heart attacks, and electrolyte imbalances. They can also be used to evaluate the effectiveness of certain medications or treatments.

Myoglobin is a protein found in the muscle tissue, particularly in red or skeletal muscles. It belongs to the globin family and has a similar structure to hemoglobin, another oxygen-binding protein found in red blood cells. Myoglobin's primary function is to store oxygen within the muscle cells, making it readily available for use during periods of increased oxygen demand, such as during physical exertion.

Myoglobin contains heme groups that bind to and release oxygen molecules. The protein has a higher affinity for oxygen than hemoglobin, allowing it to maintain its bound oxygen even in low-oxygen environments. When muscle cells are damaged or undergo necrosis (cell death), myoglobin is released into the bloodstream and can be detected in serum or urine samples. Elevated levels of myoglobin in the blood or urine may indicate muscle injury, trauma, or diseases affecting muscle integrity, such as rhabdomyolysis or muscular dystrophies.

In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.

Adenosine triphosphatases (ATPases) are a group of enzymes that catalyze the conversion of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate. This reaction releases energy, which is used to drive various cellular processes such as muscle contraction, transport of ions across membranes, and synthesis of proteins and nucleic acids.

ATPases are classified into several types based on their structure, function, and mechanism of action. Some examples include:

1. P-type ATPases: These ATPases form a phosphorylated intermediate during the reaction cycle and are involved in the transport of ions across membranes, such as the sodium-potassium pump and calcium pumps.
2. F-type ATPases: These ATPases are found in mitochondria, chloroplasts, and bacteria, and are responsible for generating a proton gradient across the membrane, which is used to synthesize ATP.
3. V-type ATPases: These ATPases are found in vacuolar membranes and endomembranes, and are involved in acidification of intracellular compartments.
4. A-type ATPases: These ATPases are found in the plasma membrane and are involved in various functions such as cell signaling and ion transport.

Overall, ATPases play a crucial role in maintaining the energy balance of cells and regulating various physiological processes.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Hypertrophic Cardiomyopathy, Familial is a genetic disorder characterized by thickening of the heart muscle (myocardium), specifically the ventricles. This thickening, or hypertrophy, can make it harder for the heart to pump blood effectively, potentially leading to symptoms such as shortness of breath, chest pain, and arrhythmias.

In familial hypertrophic cardiomyopathy, the disorder is inherited and passed down through families in an autosomal dominant pattern, meaning that a child has a 50% chance of inheriting the gene mutation from an affected parent. The condition can vary in severity even within the same family, and some individuals with the genetic mutation may not develop symptoms at all.

It is important to note that while hypertrophic cardiomyopathy can have serious consequences, many people with the condition lead normal lives with appropriate medical management and monitoring.

Acute Coronary Syndrome (ACS) is a term used to describe a range of conditions associated with sudden, reduced blood flow to the heart muscle. This reduction in blood flow, commonly caused by blood clots forming in coronary arteries, can lead to damage or death of the heart muscle and is often characterized by symptoms such as chest pain, shortness of breath, and fatigue.

There are three main types of ACS:

1. Unstable Angina: This occurs when there is reduced blood flow to the heart muscle, causing chest pain or discomfort, but the heart muscle is not damaged. It can be a warning sign for a possible future heart attack.
2. Non-ST Segment Elevation Myocardial Infarction (NSTEMI): This type of heart attack occurs when there is reduced blood flow to the heart muscle, causing damage or death of some of the muscle cells. However, the electrical activity of the heart remains relatively normal.
3. ST Segment Elevation Myocardial Infarction (STEMI): This is a serious and life-threatening type of heart attack that occurs when there is a complete blockage in one or more of the coronary arteries, causing extensive damage to the heart muscle. The electrical activity of the heart is significantly altered, which can lead to dangerous heart rhythms and even cardiac arrest.

Immediate medical attention is required for anyone experiencing symptoms of ACS, as prompt treatment can help prevent further damage to the heart muscle and reduce the risk of complications or death. Treatment options may include medications, lifestyle changes, and procedures such as angioplasty or bypass surgery.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

Striated muscle, also known as skeletal or voluntary muscle, is a type of muscle tissue that is characterized by the presence of distinct light and dark bands, or striations, when viewed under a microscope. These striations correspond to the arrangement of sarcomeres, which are the functional units of muscle fibers.

Striated muscle is under voluntary control, meaning that it is consciously activated by signals from the nervous system. It is attached to bones via tendons and is responsible for producing movements of the body. Striated muscle fibers are multinucleated, meaning that they contain many nuclei, and are composed of numerous myofibrils, which are rope-like structures that run the length of the fiber.

The myofibrils are composed of thick and thin filaments that slide past each other to cause muscle contraction. The thick filaments are made up of the protein myosin, while the thin filaments are composed of actin, tropomyosin, and troponin. When a nerve impulse arrives at the muscle fiber, it triggers the release of calcium ions from the sarcoplasmic reticulum, which bind to troponin and cause a conformational change that exposes the binding sites on actin for myosin. The myosin heads then bind to the actin filaments and pull them towards the center of the sarcomere, causing the muscle fiber to shorten and contract.

Bepridil is a calcium channel blocker medication that is used to treat angina (chest pain) and certain types of irregular heart rhythms. It works by relaxing the blood vessels and increasing the supply of oxygen and blood to the heart.

Here is the medical definition of Bepridil:

Bepridil is a non-dihydropyridine calcium channel blocker that selectively inhibits the L-type calcium channels in cardiac and smooth muscle cells, resulting in vasodilation, negative inotropic and chronotropic effects on the heart. It is used in the management of chronic stable angina pectoris and certain types of arrhythmias. The most common side effects include dizziness, headache, nausea, and constipation. Bepridil has a negative inotropic effect and should be used with caution in patients with heart failure or reduced left ventricular function. It is also metabolized by the cytochrome P450 system and can interact with other medications that are metabolized by this pathway.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

The Predictive Value of Tests, specifically the Positive Predictive Value (PPV) and Negative Predictive Value (NPV), are measures used in diagnostic tests to determine the probability that a positive or negative test result is correct.

Positive Predictive Value (PPV) is the proportion of patients with a positive test result who actually have the disease. It is calculated as the number of true positives divided by the total number of positive results (true positives + false positives). A higher PPV indicates that a positive test result is more likely to be a true positive, and therefore the disease is more likely to be present.

Negative Predictive Value (NPV) is the proportion of patients with a negative test result who do not have the disease. It is calculated as the number of true negatives divided by the total number of negative results (true negatives + false negatives). A higher NPV indicates that a negative test result is more likely to be a true negative, and therefore the disease is less likely to be present.

The predictive value of tests depends on the prevalence of the disease in the population being tested, as well as the sensitivity and specificity of the test. A test with high sensitivity and specificity will generally have higher predictive values than a test with low sensitivity and specificity. However, even a highly sensitive and specific test can have low predictive values if the prevalence of the disease is low in the population being tested.

Myosin subfragments refer to the smaller components that result from the dissociation or proteolytic digestion of myosin, a motor protein involved in muscle contraction. The two main subfragments are called S1 and S2.

S1 is the "head" of the myosin molecule, which contains the actin-binding site, ATPase activity, and the ability to generate force and motion during muscle contraction. It has a molecular weight of approximately 120 kDa.

S2 is the "tail" of the myosin molecule, which has a molecular weight of about 350 kDa and is responsible for forming the backbone of the thick filament in muscle sarcomeres. S2 can be further divided into light meromyosin (LMM) and heavy meromyosin (HMM). HMM consists of S1 and part of S2, while LMM comprises the remaining portion of S2.

These subfragments are essential for understanding myosin's structure, function, and interactions with other muscle components at a molecular level.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Restrictive cardiomyopathy (RCM) is a type of heart muscle disorder characterized by impaired relaxation and filling of the lower chambers of the heart (the ventricles), leading to reduced pump function. This is caused by stiffening or rigidity of the heart muscle, often due to fibrosis or scarring. The stiffness prevents the ventricles from filling properly with blood during the diastolic phase, which can result in symptoms such as shortness of breath, fatigue, and fluid retention.

RCM is a less common form of cardiomyopathy compared to dilated or hypertrophic cardiomyopathies. It can be idiopathic (no known cause) or secondary to other conditions like amyloidosis, sarcoidosis, or storage diseases. Diagnosis typically involves a combination of medical history, physical examination, echocardiography, and sometimes cardiac MRI or biopsy. Treatment is focused on managing symptoms and addressing underlying causes when possible.

Myocardial ischemia is a condition in which the blood supply to the heart muscle (myocardium) is reduced or blocked, leading to insufficient oxygen delivery and potential damage to the heart tissue. This reduction in blood flow typically results from the buildup of fatty deposits, called plaques, in the coronary arteries that supply the heart with oxygen-rich blood. The plaques can rupture or become unstable, causing the formation of blood clots that obstruct the artery and limit blood flow.

Myocardial ischemia may manifest as chest pain (angina pectoris), shortness of breath, fatigue, or irregular heartbeats (arrhythmias). In severe cases, it can lead to myocardial infarction (heart attack) if the oxygen supply is significantly reduced or cut off completely, causing permanent damage or death of the heart muscle. Early diagnosis and treatment of myocardial ischemia are crucial for preventing further complications and improving patient outcomes.

Brain Natriuretic Peptide (BNP) is a type of natriuretic peptide that is primarily produced in the heart, particularly in the ventricles. Although it was initially identified in the brain, hence its name, it is now known that the cardiac ventricles are the main source of BNP in the body.

BNP is released into the bloodstream in response to increased stretching or distension of the heart muscle cells due to conditions such as heart failure, hypertension, and myocardial infarction (heart attack). Once released, BNP binds to specific receptors in the kidneys, causing an increase in urine production and excretion of sodium, which helps reduce fluid volume and decrease the workload on the heart.

BNP also acts as a hormone that regulates various physiological functions, including blood pressure, cardiac remodeling, and inflammation. Measuring BNP levels in the blood is a useful diagnostic tool for detecting and monitoring heart failure, as higher levels of BNP are associated with more severe heart dysfunction.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Fluorescence spectrometry is a type of analytical technique used to investigate the fluorescent properties of a sample. It involves the measurement of the intensity of light emitted by a substance when it absorbs light at a specific wavelength and then re-emits it at a longer wavelength. This process, known as fluorescence, occurs because the absorbed energy excites electrons in the molecules of the substance to higher energy states, and when these electrons return to their ground state, they release the excess energy as light.

Fluorescence spectrometry typically measures the emission spectrum of a sample, which is a plot of the intensity of emitted light versus the wavelength of emission. This technique can be used to identify and quantify the presence of specific fluorescent molecules in a sample, as well as to study their photophysical properties.

Fluorescence spectrometry has many applications in fields such as biochemistry, environmental science, and materials science. For example, it can be used to detect and measure the concentration of pollutants in water samples, to analyze the composition of complex biological mixtures, or to study the properties of fluorescent nanomaterials.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

Protein isoforms are different forms or variants of a protein that are produced from a single gene through the process of alternative splicing, where different exons (or parts of exons) are included in the mature mRNA molecule. This results in the production of multiple, slightly different proteins that share a common core structure but have distinct sequences and functions. Protein isoforms can also arise from genetic variations such as single nucleotide polymorphisms or mutations that alter the protein-coding sequence of a gene. These differences in protein sequence can affect the stability, localization, activity, or interaction partners of the protein isoform, leading to functional diversity and specialization within cells and organisms.

An immunoassay is a biochemical test that measures the presence or concentration of a specific protein, antibody, or antigen in a sample using the principles of antibody-antigen reactions. It is commonly used in clinical laboratories to diagnose and monitor various medical conditions such as infections, hormonal disorders, allergies, and cancer.

Immunoassays typically involve the use of labeled reagents, such as enzymes, radioisotopes, or fluorescent dyes, that bind specifically to the target molecule. The amount of label detected is proportional to the concentration of the target molecule in the sample, allowing for quantitative analysis.

There are several types of immunoassays, including enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), fluorescence immunoassay (FIA), and chemiluminescent immunoassay (CLIA). Each type has its own advantages and limitations, depending on the sensitivity, specificity, and throughput required for a particular application.

Cardiomyopathies are a group of diseases that affect the heart muscle, leading to mechanical and/or electrical dysfunction. The American Heart Association (AHA) defines cardiomyopathies as "a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not always) exhibit inappropriate ventricular hypertrophy or dilatation and frequently lead to heart failure."

There are several types of cardiomyopathies, including:

1. Dilated cardiomyopathy (DCM): This is the most common type of cardiomyopathy, characterized by an enlarged left ventricle and impaired systolic function, leading to heart failure.
2. Hypertrophic cardiomyopathy (HCM): In this type, there is abnormal thickening of the heart muscle, particularly in the septum between the two ventricles, which can obstruct blood flow and increase the risk of arrhythmias.
3. Restrictive cardiomyopathy (RCM): This is a rare form of cardiomyopathy characterized by stiffness of the heart muscle, impaired relaxation, and diastolic dysfunction, leading to reduced filling of the ventricles and heart failure.
4. Arrhythmogenic right ventricular cardiomyopathy (ARVC): In this type, there is replacement of the normal heart muscle with fatty or fibrous tissue, primarily affecting the right ventricle, which can lead to arrhythmias and sudden cardiac death.
5. Unclassified cardiomyopathies: These are conditions that do not fit into any of the above categories but still significantly affect the heart muscle and function.

Cardiomyopathies can be caused by genetic factors, acquired conditions (e.g., infections, toxins, or autoimmune disorders), or a combination of both. The diagnosis typically involves a comprehensive evaluation, including medical history, physical examination, electrocardiogram (ECG), echocardiography, cardiac magnetic resonance imaging (MRI), and sometimes genetic testing. Treatment depends on the type and severity of the condition but may include medications, lifestyle modifications, implantable devices, or even heart transplantation in severe cases.

Prognosis is a medical term that refers to the prediction of the likely outcome or course of a disease, including the chances of recovery or recurrence, based on the patient's symptoms, medical history, physical examination, and diagnostic tests. It is an important aspect of clinical decision-making and patient communication, as it helps doctors and patients make informed decisions about treatment options, set realistic expectations, and plan for future care.

Prognosis can be expressed in various ways, such as percentages, categories (e.g., good, fair, poor), or survival rates, depending on the nature of the disease and the available evidence. However, it is important to note that prognosis is not an exact science and may vary depending on individual factors, such as age, overall health status, and response to treatment. Therefore, it should be used as a guide rather than a definitive forecast.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.

Cardiac myosins are a type of myosin protein that are specifically expressed in the cardiac muscle cells (or cardiomyocytes) of the heart. These proteins play a crucial role in the contraction and relaxation of heart muscles, which is essential for proper heart function and blood circulation.

Myosins are molecular motors that use chemical energy from ATP to generate force and movement. In the context of cardiac muscle cells, cardiac myosins interact with another protein called actin to form sarcomeres, which are the basic contractile units of muscle fibers. During contraction, the heads of cardiac myosin molecules bind to actin filaments and pull them together, causing the muscle fiber to shorten and generate force.

There are different isoforms of cardiac myosins that can vary in their structure and function. Mutations in the genes encoding these proteins have been linked to various forms of cardiomyopathy, which are diseases of the heart muscle that can lead to heart failure and other complications. Therefore, understanding the structure and function of cardiac myosins is an important area of research for developing therapies and treatments for heart disease.

Calmodulin is a small, ubiquitous calcium-binding protein that plays a critical role in various intracellular signaling pathways. It functions as a calcium sensor, binding to and regulating the activity of numerous target proteins upon calcium ion (Ca^2+^) binding. Calmodulin is expressed in all eukaryotic cells and participates in many cellular processes, including muscle contraction, neurotransmitter release, gene expression, metabolism, and cell cycle progression.

The protein contains four EF-hand motifs that can bind Ca^2+^ ions. Upon calcium binding, conformational changes occur in the calmodulin structure, exposing hydrophobic surfaces that facilitate its interaction with target proteins. Calmodulin's targets include enzymes (such as protein kinases and phosphatases), ion channels, transporters, and cytoskeletal components. By modulating the activity of these proteins, calmodulin helps regulate essential cellular functions in response to changes in intracellular Ca^2+^ concentrations.

Calmodulin's molecular weight is approximately 17 kDa, and it consists of a single polypeptide chain with 148-150 amino acid residues. The protein can be found in both the cytoplasm and the nucleus of cells. In addition to its role as a calcium sensor, calmodulin has been implicated in various pathological conditions, including cancer, neurodegenerative diseases, and cardiovascular disorders.

Strontium is not a medical term, but it is a chemical element with the symbol Sr and atomic number 38. It is a soft silver-white or yellowish metallic element that is highly reactive chemically. In the medical field, strontium ranelate is a medication used to treat osteoporosis in postmenopausal women. It works by increasing the formation of new bone and decreasing bone resorption (breakdown).

It is important to note that strontium ranelate has been associated with an increased risk of cardiovascular events, such as heart attack and stroke, so it is not recommended for people with a history of these conditions. Additionally, the use of strontium supplements in high doses can be toxic and should be avoided.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

"Pectinidae" is not a medical term. It is a taxonomic category in the field of biology, specifically a family of marine bivalve mollusks commonly known as scallops. The members of this family are characterized by their fan-shaped shells and their ability to swim by clapping their valves together. If you have any questions about a medical term, I would be happy to help with that instead.

An acute disease is a medical condition that has a rapid onset, develops quickly, and tends to be short in duration. Acute diseases can range from minor illnesses such as a common cold or flu, to more severe conditions such as pneumonia, meningitis, or a heart attack. These types of diseases often have clear symptoms that are easy to identify, and they may require immediate medical attention or treatment.

Acute diseases are typically caused by an external agent or factor, such as a bacterial or viral infection, a toxin, or an injury. They can also be the result of a sudden worsening of an existing chronic condition. In general, acute diseases are distinct from chronic diseases, which are long-term medical conditions that develop slowly over time and may require ongoing management and treatment.

Examples of acute diseases include:

* Acute bronchitis: a sudden inflammation of the airways in the lungs, often caused by a viral infection.
* Appendicitis: an inflammation of the appendix that can cause severe pain and requires surgical removal.
* Gastroenteritis: an inflammation of the stomach and intestines, often caused by a viral or bacterial infection.
* Migraine headaches: intense headaches that can last for hours or days, and are often accompanied by nausea, vomiting, and sensitivity to light and sound.
* Myocardial infarction (heart attack): a sudden blockage of blood flow to the heart muscle, often caused by a buildup of plaque in the coronary arteries.
* Pneumonia: an infection of the lungs that can cause coughing, chest pain, and difficulty breathing.
* Sinusitis: an inflammation of the sinuses, often caused by a viral or bacterial infection.

It's important to note that while some acute diseases may resolve on their own with rest and supportive care, others may require medical intervention or treatment to prevent complications and promote recovery. If you are experiencing symptoms of an acute disease, it is always best to seek medical attention to ensure proper diagnosis and treatment.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Clinical chemistry tests are a type of laboratory test that measure the levels of various chemicals or substances in the body. These tests can be used to help diagnose and monitor a wide range of medical conditions, including diabetes, liver disease, heart disease, and kidney disease. Some common clinical chemistry tests include:

1. Blood glucose test: Measures the level of glucose (sugar) in the blood. This test is commonly used to diagnose and monitor diabetes.
2. Electrolyte panel: Measures the levels of important electrolytes such as sodium, potassium, chloride, and bicarbonate in the blood. Imbalances in these electrolytes can indicate a variety of medical conditions.
3. Liver function tests (LFTs): Measure the levels of various enzymes and proteins produced by the liver. Abnormal results can indicate liver damage or disease.
4. Kidney function tests: Measure the levels of various substances such as creatinine and blood urea nitrogen (BUN) in the blood. Elevated levels of these substances can indicate kidney dysfunction or disease.
5. Lipid panel: Measures the levels of different types of cholesterol and triglycerides in the blood. Abnormal results can indicate an increased risk of heart disease.
6. Thyroid function tests: Measure the levels of hormones produced by the thyroid gland. Abnormal results can indicate thyroid dysfunction or disease.

Clinical chemistry tests are usually performed on a sample of blood, urine, or other bodily fluid. The results of these tests can provide important information to help doctors diagnose and manage medical conditions.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Cardiotonic agents are a type of medication that have a positive inotropic effect on the heart, meaning they help to improve the contractility and strength of heart muscle contractions. These medications are often used to treat heart failure, as they can help to improve the efficiency of the heart's pumping ability and increase cardiac output.

Cardiotonic agents work by increasing the levels of calcium ions inside heart muscle cells during each heartbeat, which in turn enhances the force of contraction. Some common examples of cardiotonic agents include digitalis glycosides (such as digoxin), which are derived from the foxglove plant, and synthetic medications such as dobutamine and milrinone.

While cardiotonic agents can be effective in improving heart function, they can also have potentially serious side effects, including arrhythmias, electrolyte imbalances, and digestive symptoms. As a result, they are typically used under close medical supervision and their dosages may need to be carefully monitored to minimize the risk of adverse effects.

A Receiver Operating Characteristic (ROC) curve is a graphical representation used in medical decision-making and statistical analysis to illustrate the performance of a binary classifier system, such as a diagnostic test or a machine learning algorithm. It's a plot that shows the tradeoff between the true positive rate (sensitivity) and the false positive rate (1 - specificity) for different threshold settings.

The x-axis of an ROC curve represents the false positive rate (the proportion of negative cases incorrectly classified as positive), while the y-axis represents the true positive rate (the proportion of positive cases correctly classified as positive). Each point on the curve corresponds to a specific decision threshold, with higher points indicating better performance.

The area under the ROC curve (AUC) is a commonly used summary measure that reflects the overall performance of the classifier. An AUC value of 1 indicates perfect discrimination between positive and negative cases, while an AUC value of 0.5 suggests that the classifier performs no better than chance.

ROC curves are widely used in healthcare to evaluate diagnostic tests, predictive models, and screening tools for various medical conditions, helping clinicians make informed decisions about patient care based on the balance between sensitivity and specificity.

Dilated cardiomyopathy (DCM) is a type of cardiomyopathy characterized by the enlargement and weakened contraction of the heart's main pumping chamber (the left ventricle). This enlargement and weakness can lead to symptoms such as shortness of breath, fatigue, and fluid retention. DCM can be caused by various factors including genetics, viral infections, alcohol and drug abuse, and other medical conditions like high blood pressure and diabetes. It is important to note that this condition can lead to heart failure if left untreated.

Calcium-binding proteins (CaBPs) are a diverse group of proteins that have the ability to bind calcium ions (Ca^2+^) with high affinity and specificity. They play crucial roles in various cellular processes, including signal transduction, muscle contraction, neurotransmitter release, and protection against oxidative stress.

The binding of calcium ions to these proteins induces conformational changes that can either activate or inhibit their functions. Some well-known CaBPs include calmodulin, troponin C, S100 proteins, and parvalbumins. These proteins are essential for maintaining calcium homeostasis within cells and for mediating the effects of calcium as a second messenger in various cellular signaling pathways.

Skeletal muscle fibers, also known as striated muscle fibers, are the type of muscle cells that make up skeletal muscles, which are responsible for voluntary movements of the body. These muscle fibers are long, cylindrical, and multinucleated, meaning they contain multiple nuclei. They are surrounded by a connective tissue layer called the endomysium, and many fibers are bundled together into fascicles, which are then surrounded by another layer of connective tissue called the perimysium.

Skeletal muscle fibers are composed of myofibrils, which are long, thread-like structures that run the length of the fiber. Myofibrils contain repeating units called sarcomeres, which are responsible for the striated appearance of skeletal muscle fibers. Sarcomeres are composed of thick and thin filaments, which slide past each other during muscle contraction to shorten the sarcomere and generate force.

Skeletal muscle fibers can be further classified into two main types based on their contractile properties: slow-twitch (type I) and fast-twitch (type II). Slow-twitch fibers have a high endurance capacity and are used for sustained, low-intensity activities such as maintaining posture. Fast-twitch fibers, on the other hand, have a higher contractile speed and force generation capacity but fatigue more quickly and are used for powerful, explosive movements.

Titrimetry is a type of analytical technique used in chemistry and medicine to determine the concentration of a substance (analyte) in a solution. It involves a controlled addition of a reagent, called a titrant, with a known concentration and volume, into the analyte solution until the reaction between them is complete. This point is commonly determined by a change in the physical or chemical properties of the solution, such as a color change, which is indicated by a visual endpoint or an electrical endpoint using a pH or redox electrode.

The volume of titrant added is then used to calculate the concentration of the analyte using the stoichiometry of the reaction and the concentration of the titrant. Titrimetry is widely used in medical laboratories for various applications, such as determining the amount of active ingredients in pharmaceuticals, measuring the strength of acid or base solutions, and assessing the hardness of water.

Heart disease is a broad term for a class of diseases that involve the heart or blood vessels. It's often used to refer to conditions that include:

1. Coronary artery disease (CAD): This is the most common type of heart disease. It occurs when the arteries that supply blood to the heart become hardened and narrowed due to the buildup of cholesterol and other substances, which can lead to chest pain (angina), shortness of breath, or a heart attack.

2. Heart failure: This condition occurs when the heart is unable to pump blood efficiently to meet the body's needs. It can be caused by various conditions, including coronary artery disease, high blood pressure, and cardiomyopathy.

3. Arrhythmias: These are abnormal heart rhythms, which can be too fast, too slow, or irregular. They can lead to symptoms such as palpitations, dizziness, and fainting.

4. Valvular heart disease: This involves damage to one or more of the heart's four valves, which control blood flow through the heart. Damage can be caused by various conditions, including infection, rheumatic fever, and aging.

5. Cardiomyopathy: This is a disease of the heart muscle that makes it harder for the heart to pump blood efficiently. It can be caused by various factors, including genetics, viral infections, and drug abuse.

6. Pericardial disease: This involves inflammation or other problems with the sac surrounding the heart (pericardium). It can cause chest pain and other symptoms.

7. Congenital heart defects: These are heart conditions that are present at birth, such as a hole in the heart or abnormal blood vessels. They can range from mild to severe and may require medical intervention.

8. Heart infections: The heart can become infected by bacteria, viruses, or parasites, leading to various symptoms and complications.

It's important to note that many factors can contribute to the development of heart disease, including genetics, lifestyle choices, and certain medical conditions. Regular check-ups and a healthy lifestyle can help reduce the risk of developing heart disease.

Phosphorylation is the process of adding a phosphate group (a molecule consisting of one phosphorus atom and four oxygen atoms) to a protein or other organic molecule, which is usually done by enzymes called kinases. This post-translational modification can change the function, localization, or activity of the target molecule, playing a crucial role in various cellular processes such as signal transduction, metabolism, and regulation of gene expression. Phosphorylation is reversible, and the removal of the phosphate group is facilitated by enzymes called phosphatases.

Magnesium is an essential mineral that plays a crucial role in various biological processes in the human body. It is the fourth most abundant cation in the body and is involved in over 300 enzymatic reactions, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. Magnesium also contributes to the structural development of bones and teeth.

In medical terms, magnesium deficiency can lead to several health issues, such as muscle cramps, weakness, heart arrhythmias, and seizures. On the other hand, excessive magnesium levels can cause symptoms like diarrhea, nausea, and muscle weakness. Magnesium supplements or magnesium-rich foods are often recommended to maintain optimal magnesium levels in the body.

Some common dietary sources of magnesium include leafy green vegetables, nuts, seeds, legumes, whole grains, and dairy products. Magnesium is also available in various forms as a dietary supplement, including magnesium oxide, magnesium citrate, magnesium chloride, and magnesium glycinate.

Mollusca is not a medical term per se, but a major group of invertebrate animals that includes snails, clams, octopuses, and squids. However, medically, some mollusks can be relevant as they can act as vectors for various diseases, such as schistosomiasis (transmitted by freshwater snails) and fascioliasis (transmitted by aquatic snails). Therefore, a medical definition might describe Mollusca as a phylum of mostly marine invertebrates that can sometimes play a role in the transmission of certain infectious diseases.

Isoenzymes, also known as isoforms, are multiple forms of an enzyme that catalyze the same chemical reaction but differ in their amino acid sequence, structure, and/or kinetic properties. They are encoded by different genes or alternative splicing of the same gene. Isoenzymes can be found in various tissues and organs, and they play a crucial role in biological processes such as metabolism, detoxification, and cell signaling. Measurement of isoenzyme levels in body fluids (such as blood) can provide valuable diagnostic information for certain medical conditions, including tissue damage, inflammation, and various diseases.

Fast-twitch muscle fibers, also known as type II fibers, are a type of skeletal muscle fiber that are characterized by their rapid contraction and relaxation rates. These fibers have a larger diameter and contain a higher concentration of glycogen, which serves as a quick source of energy for muscle contractions. Fast-twitch fibers are further divided into two subcategories: type IIa and type IIb (or type IIx). Type IIa fibers have a moderate amount of mitochondria and can utilize both aerobic and anaerobic metabolic pathways, making them fatigue-resistant. Type IIb fibers, on the other hand, have fewer mitochondria and primarily use anaerobic metabolism, leading to faster fatigue. Fast-twitch fibers are typically used in activities that require quick, powerful movements such as sprinting or weightlifting.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

Slow-twitch muscle fibers, also known as type I muscle fibers, are specialized skeletal muscle cells that contract relatively slowly and generate less force than fast-twitch fibers. However, they can maintain contraction for longer periods of time and have a higher resistance to fatigue. These fibers primarily use oxygen and aerobic metabolism to produce energy, making them highly efficient during prolonged, lower-intensity activities such as long-distance running or cycling. Slow-twitch muscle fibers also have an abundant blood supply, which allows for efficient delivery of oxygen and removal of waste products.

... , or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that are ... Calcium-binding protein Troponin C Troponin I Troponin T PDB: 1J1E​; Takeda S, Yamashita A, Maeda K, Maeda Y (2003). "Structure ... Troponin is found in both skeletal muscle and cardiac muscle, but the specific versions of troponin differ between types of ... Troponin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Troponins at Lab Tests Online (CS1 maint: ...
Slow skeletal troponin T1, TNNT1 (19q13.4, 191041) Cardiac troponin T2, TNNT2 (1q32, 191045) Fast skeletal troponin T3, TNNT3 ( ... Troponin T (shortened TnT or TropT) is a part of the troponin complex, which are proteins integral to the contraction of ... Troponin T binds to tropomyosin and helps position it on actin, and together with the rest of the troponin complex, modulates ... He also developed the troponin T assay. In patients with stable coronary artery disease, the troponin T concentration has long ...
Troponin Troponin T Troponin C Sliding filament model Takeda, Soichi; Yamashita, Atsuko; Maeda, Kayo; Maéda, Yuichiro (July ... Troponin I is a cardiac and skeletal muscle protein family. It is a part of the troponin protein complex, where it binds to ... Reductions in troponin I levels proved to reduce the risk of future CVD. - High sensitive troponin I used as a screening tool ... Troponin I prevents myosin from binding to actin in relaxed muscle. When calcium binds to the troponin C, it causes ...
A8V D145E A31S C84Y E134D Y5H I148V Troponin Troponin T Troponin I Calcium-binding protein Sliding filament model Kalyva A, ... Troponin C is a protein which is part of the troponin complex. It contains four calcium-binding EF hands, although different ... Fast troponin C, TNNC2 (20q12-q13.11, Online Mendelian Inheritance in Man (OMIM): 191039) Point mutations can occur in troponin ... The C lobe serves a structural purpose and binds to the N domain of troponin I (TnI). The C lobe can bind either Ca2+ or Mg2+. ...
Chemical compounds can bind to troponin C to act as troponin activators (calcium sensitizers) or troponin inhibitors (calcium ... and cardiac troponin T (cTnT), whereas cTnC binds to slow skeletal troponin I (ssTnI) and troponin T (ssTnT) in slow-twitch ... Troponin C, also known as TN-C or TnC, is a protein that resides in the troponin complex on actin thin filaments of striated ... Troponin C is encoded by the TNNC1 gene in humans for both cardiac and slow skeletal muscle. Cardiac troponin C (cTnC) is a 161 ...
... is a protein that in humans is encoded by the TNNC2 gene. Troponin (Tn), is a key protein complex ... 1998). "Crystal structure of troponin C in complex with troponin I fragment at 2.3-A resolution". Proc. Natl. Acad. Sci. U.S.A ... 1997). "Fine mapping of five human skeletal muscle genes: alpha-tropomyosin, beta-tropomyosin, troponin-I slow-twitch, troponin ... "Entrez Gene: TNNC2 troponin C type 2 (fast)". Romero-Herrera AE, Castillo O, Lehmann H (1977). "Human skeletal muscle proteins ...
... troponin C which is calcium binding, troponin T that plays the role with tropomyosin, and troponin I which has an inhibitory ... Solaro, R. John; Rosevear, Paul; Kobayashi, Tomoyoshi (April 2008). "The unique functions of cardiac troponin I in the control ... A8V is point mutation on Troponin C (cTNC) that leads to a hypertrophic cardiomyopathy. The coordinated cardiac muscle ... Ohtsuki, Iwao; Morimoto, Sachio (April 2008). "Troponin: Regulatory function and disorders". Biochemical and Biophysical ...
Cardiac TnT is the largest of the three troponin subunits (cTnT, troponin I (TnI), troponin C (TnC)) on the actin thin filament ... "Dephosphorylation specificities of protein phosphatase for cardiac troponin I, troponin T, and sites within troponin T". ... He X, Liu Y, Sharma V, Dirksen RT, Waugh R, Sheu SS, Min W (Jul 2003). "ASK1 associates with troponin T and induces troponin T ... Noland TA, Raynor RL, Kuo JF (Dec 1989). "Identification of sites phosphorylated in bovine cardiac troponin I and troponin T by ...
In 2006, his essay "Troponin trumps common sense", which discussed the appropriate use of the troponin test, drew the attention ... In a reply, he stated "rather than allowing troponin to trump common sense, we should inject more common sense into the process ... "Reply: Troponin Trumps Common Sense" (PDF). Journal of the American College of Cardiology. 48: 2357-2358. 5 December 2006. ... Other noted publications have included his 2006 article titled "Troponin trumps common sense" and "Women Cardiologists: Why so ...
"Troponins". medscape. Retrieved 2017-07-24. Updated: Jan 14, 2015 Brenden CK, Hollander JE, Guss D, et al. (May 2006). "Gray ... In addition, some values, including troponin I and brain natriuretic peptide, are given as the estimated appropriate cutoffs to ... Baum, Hannsjörg; Hinze, Anika; Bartels, Peter; Neumeier, Dieter (2004-12-01). "Reference values for cardiac troponins T and I ... High sensitive troponin I in pediatric age". Clinica Chimica Acta. 458: 68-71. doi:10.1016/j.cca.2016.04.029. ISSN 0009-8981. ...
Troponin...etc.). A small portion of carryover could lead to erroneous results. IUPAC made a recommendation in 1991 for the ... carryover of cardiac High sensitivity Troponin assay would be catastrophic. Haeckel, R. (1991-01-01). "Proposals for the ...
Fetal Troponin T is a cardiac protein found in adults and infants. There are 4 Troponin T (TnT) isoforms found in fetal cardiac ... Fetal Troponin T and Troponin I isoforms. Fetal Hemoglobin is a member of erythrocytes called F-cells. It is a tetramer protein ... Fetal Troponin I (TnI) is a cardiac and skeletal protein found in adults and infants, with isomers specific to each. Two ... Anderson, P A; Malouf, N N; Oakeley, A E; Pagani, E D; Allen, P D (November 1991). "Troponin T isoform expression in humans. A ...
A novel troponin T-like protein". Hypertension. 11 (6 Pt 2): 620-6. doi:10.1161/01.hyp.11.6.620. PMID 2455687. Coulier F, ...
Troponin levels should also be ordered. Important to note, negative findings on both ECG and troponin levels do not exclude BCI ... If both ECG and troponin levels are abnormal, an appropriate next step in evaluation would involve ordering an echocardiography ... As mentioned under Evaluation, an abnormal ECG and elevated troponin levels should elicit continued cardiac monitoring to look ...
A novel troponin T-like protein". Hypertension. 11 (6 Pt 2): 620-6. doi:10.1161/01.hyp.11.6.620. PMID 2455687. Taylor A, Erba ... troponin C, Alzheimer amyloid precursor protein and pro-interleukin 1 beta as substrates of the protease from human ...
Calbindin Calmodulin Calsequestrin Troponin Kinjo, Tashi G; Schnetkamp, Paul PM. Ca2+ Chemistry, Storage and Transport in ...
Pfleiderer P, Sumandea MP, Rybin VO, Wang C, Steinberg SF (2009). "Raf-1: a novel cardiac troponin T kinase". J. Muscle Res. ... cardiac muscle troponin T (TnTc), etc. The retinoblastoma protein (pRb) and Cdc25 phosphatase were also suggested as possible ...
... does not contain the protein troponin; instead calmodulin (which takes on the regulatory role in smooth muscle), ... Contraction is initiated by a calcium-regulated phosphorylation of myosin, rather than a calcium-activated troponin system. ... smooth muscle does not contain the calcium-binding protein troponin. ...
Troponin "CREATINE KINASE - MB CK-MB LQ" (PDF). Cabaniss, C. Daniel (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. ... the test has been superseded by the troponin test. However, recently, there have been improvements to the test that involve ...
Sensitizing troponin-C to the effects of calcium. Phosphorylating L-type calcium channels. This will increase their ... More calcium available for Troponin to use will increase the force developed. Decreasing contractility is done primarily by ...
Li Q, Shen PY, Wu G, Chen XZ (January 2003). "Polycystin-2 interacts with troponin I, an angiogenesis inhibitor". Biochemistry ...
It is a tissue-specific subtype of troponin I, which in turn is a part of the troponin complex. The TNNI3 gene encoding cardiac ... Vassylyev DG, Takeda S, Wakatsuki S, Maeda K, Maéda Y (Apr 1998). "Crystal structure of troponin C in complex with troponin I ... Noland TA, Raynor RL, Kuo JF (Dec 1989). "Identification of sites phosphorylated in bovine cardiac troponin I and troponin T by ... Martin AF (Jan 1981). "Turnover of cardiac troponin subunits. Kinetic evidence for a precursor pool of troponin-I". The Journal ...
Shah, Ajay M.; Solaro, R. John; Layland, Joanne (2005-04-01). "Regulation of cardiac contractile function by troponin I ... troponin I, myosin binding protein C, and potassium channels. This increases inotropy as well as lusitropy, increasing ...
Serum troponin elevation is a characteristic biomarker of MI. Depending on the severity of ischemia, MIs are categorized as ... Wu AH (2017-09-01). "Release of cardiac troponin from healthy and damaged myocardium". Frontiers in Laboratory Medicine. 1 (3 ... Lactate accumulation reduces contractility and eventually necroses cardiomyocytes, releasing their troponin storage into the ...
Calcium ions also combine with the regulatory protein troponin C in the troponin complex to enable contraction of the cardiac ... Two tests of troponin are often taken-one at the time of initial presentation, and another within 3-6 hours, with either a high ... Troponin is a sensitive biomarker for a heart with insufficient blood supply. It is released 4-6 hours after injury, and ... These are mostly associated with muscle contraction, and bind with actin, myosin, tropomyosin, and troponin. They include MYH6 ...
Tanokura M, Ohtsuki I (1984). "Interactions among chymotryptic troponin T subfragments, tropomyosin, troponin I and troponin C ... Pearlstone JR, Smillie LB (1983). "Effects of troponin-I plus-C on the binding of troponin-T and its fragments to alpha- ... In human cardiac muscle the ratio of α-Tm to β-Tm is roughly 5:1. Tm functions in association with the troponin complex to ... In addition to actin, Tm binds troponin T (TnT). TnT tethers the region of head-to-tail overlap of subsequent Tm molecules to ...
H-FABP measured with troponin shows increased sensitivity of 20.6% over troponin at 3-6 hours following chest pain onset. This ... The effectiveness of using the combination of H-FABP with troponin to diagnose MI within 6 hours is well reported. In addition ... FABP3 is known to interact with TNNI3K in the context of interacting with cardiac troponin I. The protein also interacts with, ... Alongside D-dimer, NT-proBNP and peak troponin T, it was the only cardiac biomarker that proved to be a statistically ...
Troponin levels increase in 35-50% of people with pericarditis. Electrocardiogram (ECG) changes in acute pericarditis mainly ... Acute pericarditis is associated with a modest increase in serum creatine kinase MB (CK-MB). and cardiac troponin I (cTnI), ...
Tsalkova TN, Privalov PL (1985). "Thermodynamic study of domain organization in troponin C and calmodulin". Journal of ...
Calcium ions then bind to troponin, which is associated with tropomyosin. Binding causes changes in the shape of troponin and ... In animals, it is an important component of the muscular system which works in conjunction with troponin to regulate muscle ... The thin filament is made of actin, tropomyosin, and troponin. The contraction of skeletal muscle is triggered by nerve ... Structural and biochemical studies suggest that the position of tropomyosin and troponin on the thin filament regulates the ...
Troponin, or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that are ... Calcium-binding protein Troponin C Troponin I Troponin T PDB: 1J1E​; Takeda S, Yamashita A, Maeda K, Maeda Y (2003). "Structure ... Troponin is found in both skeletal muscle and cardiac muscle, but the specific versions of troponin differ between types of ... Troponin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Troponins at Lab Tests Online (CS1 maint: ...
Cardiac troponin I (cTnI) is frequently used to help determine whether a patient with chest pain has had cardiac damage. A ... Table 2. Positive and Negative Predictive Value of the Troponin I Test at 6 Hours of Chest Pain Predicted. Prevalence. Patients ... Cite this: False-Positive Troponin I in a Young Healthy Woman with Chest Pain - Medscape - May 01, 2002. ... False-Positive Troponin I in a Young Healthy Woman with Chest Pain ...
Review factors determining the magnitude of exercise-induced cardiac troponin release, the mechanisms responsible, and the ... high sensitivity cardiac troponin T; hs-cTnI, high sensitivity cardiac troponin I; and URL, upper reference limit. ... high sensitivity cardiac troponin I; hs-cTnT, high sensitivity cardiac troponin T; MACE, major adverse cardiovascular outcome; ... Exercise-induced Cardiac Troponin Elevations. From Underlying Mechanisms to Clinical Relevance. Vincent L. Aengevaeren, MD, PhD ...
High troponin levels may be a sign of a heart attack. Learn more. ... A troponin test measures the level of troponin in your blood. ... What is a troponin test?. A troponin test measures the level of troponin in a sample of your blood. Troponin is a protein ... Other names: cardiac troponin I (cTnI), cardiac troponin T (cTnT), cardiac troponin (cTn), cardiac-specific troponin I and ... Troponin; p. 492-3.. *Maynard SJ, Menown IB, Adgey AA. Troponin T or troponin I as cardiac markers in ischaemic heart disease. ...
Preliminary investigation of serum cardiac troponin I in dogs with acute ischaemic stroke by Rita Gonçalves and colleagues at ... Serum cardiac troponin I levels were elevated in dogs with acute ischaemic stroke, although they had no prognostic value in ... Cardiac troponins are routinely used as biomarkers for the diagnosis of acute myocardial infarction in humans, and increased ... Preliminary investigation of serum cardiac troponin I in dogs with acute ischaemic stroke by Rita Gonçalves and colleagues at ...
Cardiac troponin (cTn) is the biomarker of choice for detecting myocardial necrosis and assessing acute ischemic changes ... Association of troponin T detected with a highly sensitive assay and cardiac structure and mortality risk in the general ... Cardiac troponin testing in the acute care setting: Ordering, reporting, and high sensitivity assays-an update from the ... Cardiac troponin (cTn) is the biomarker of choice for detecting myocardial necrosis and assessing acute ischemic changes ...
Troponin Levels. Troponin is a contractile protein that normally is not found in serum. It is released only when myocardial ... Improved cardiac troponin assays offer even greater diagnostic accuracy than the standard assays do, according to a study by ... Troponin levels are now considered to be the criterion standard for defining and diagnosing myocardial infarction, according to ... Positive troponin levels are considered virtually diagnostic of myocardial infarction, according to a revised version of the ...
What Does Elevated Troponin Mean in COVID-19?. - Roughly one in five admitted in Wuhan had apparent cardiac injury. by Nicole ... On the basis of the present results of [high-sensitivity troponin I] and ECG findings in a subset of patients, we can only ... "Some clinicians have said they measure troponin in their COVID-19 patients to provide guidance on therapy," he said. "My hope ... Abnormally high levels of high-sensitivity cardiac troponin I (above the 99th-percentile upper reference limit) were observed ...
Testing Status of Comparison study of Aminopyridines/Troponin levels 10058. Testing Status of Comparison study of ... Aminopyridines/Troponin levels 10058. CASRN: AMINOPYRCOMP. Related: 2, 3, & 4-aminopyridine. Secondary: *462-08-8 - 3- ...
p>Troponin Pairs for Immunoassays. Need a Custom Solution? We offer unparalleled collaboration and support to assist you with ... Troponin Pairs for Immunoassays. Need a Custom Solution?. We offer unparalleled collaboration and support to assist you with ...
What are the potential mechanisms underlying troponin elevation with COVID-19 infection? Rise and/or fall of troponin ... Keywords: Cardiology Magazine, ACC Publications, Coronavirus, Troponin, Fibrinolytic Agents, Peptidyl-Dipeptidase A, ... Troponin and BNP Use in COVID-19. Mar 18, 2020 Cardiology Magazine. *. Print. ... An abnormal troponin or natriuretic peptide result should not be considered evidence for an acute MI or heart failure without ...
... Aug 14, 2012 , Magazine: Journal of ... It has also been demonstrated that single time-point troponin concentration displays a strong correlation with infarct size (2, ... and troponins positively correlate with infarct size as measured by using the gold standard techniques (2). ...
Troponin T (TnT) is one of the three subunits that form troponin (Tn) which together with tropomyosin is responsible for the ... Troponin T (TnT) is one of the three subunits that form troponin (Tn) which together with tropomyosin is responsible for the ... Role of troponin T in disease Aldrin V Gomes 1 , Junor A Barnes, Keita Harada, James D Potter ... Role of troponin T in disease Aldrin V Gomes et al. Mol Cell Biochem. 2004 Aug. ...
... Identify chest pain patients at low-risk for major ... Consider serial troponins in low-dependency environment (eg. ED observation ward).. *Scores of ≥ 0.05 and , 0.95 = Moderate ... Consider serial troponins in low-dependency environment (eg. ED observation ward).. *Scores of ≥ 0.05 and , 0.95 = Moderate ... The Troponin-only Manchester Acute Coronary Syndromes (T-MACS) decision aid is a derived and validated cardiac risk ...
Use of High-Sensitivity Troponin Values in Suspected ACS Induces Few Changes in Practice By Todd Neale ... For standard troponin testing, , 29 ng/L was considered normal, 30 to 100 ng/L deemed borderline abnormal, and , 100 ng/L ... The Elecsys Troponin T high sensitive assay (Roche Diagnostics) was used in all cases; only the reports provided to physicians ... Contributing to that fear is the greater use of troponin testing by US physicians compared with those in other parts of the ...
While calcium binding to troponin C (TnC) triggers the contraction of both skeletal and cardiac muscle, there is clear evidence ... Binding of cardiac troponin-I147-163 induces a structural opening in human cardiac troponin-C. Li MX, Spyracopoulos L, Sykes BD ... Calcium-induced structural transition in the regulatory domain of human cardiac troponin C L Spyracopoulos 1 , M X Li, S K Sia ... Calcium-induced structural transition in the regulatory domain of human cardiac troponin C L Spyracopoulos et al. Biochemistry. ...
Rapid rule-out of acute myocardial infarction with a single high-sensitivity cardiac troponin T measurement below the limit of ... Acute myocardial infarction can be ruled out with a single high-sensitivity cardiac troponin T level ... Acute myocardial infarction can be ruled out with a single high-sensitivity cardiac troponin T level ... if the first high-sensitivity cardiac troponin T (hs-cTnT) measurement was ,5 ng/L.2 The authors suggested that it was safe to ...
Acute myocardial infarction, Cost-effectiveness, Decision model, High-sensitive troponin T Persistent URL ... High-sensitive Troponin T assay for the diagnosis of acute myocardial infarction: An economic evaluation. Publication. ... Since conventional cardiac Troponin assays have a low sensitivity for diagnosing AMI in the first hours after myocardial ... The aim of this study was to assess the cost effectiveness of a high-sensitive Troponin T assay (hsTnT), alone or combined with ...
troponin. Study Ties COVID-19-Related Syndrome in Kids to Altered Immune System Posted on September 1st, 2020. by Dr. Francis ... alongside raised levels of other markers suggesting tissue damage-such as troponin, which indicates heart muscle injury. ...
non‐CV ones). Troponin helped in predicting CV death only, whereas NT‐proBNP helped in the prediction of both CV and non‐CV ... Cardiovascular and non‐cardiovascular death distinction: the utility of troponin beyond N‐terminal pro‐B‐type natriuretic ... 2020) Cardiovascular and non‐cardiovascular death distinction: the utility of troponin beyond N‐terminal pro‐B‐type natriuretic ... and troponin (c‐index = 0.73). The non‐CV death model incorporated age , 75 years, anaemia and elevated NT‐proBNP (c‐index = ...
N2 - Troponin T is one of the most commonly used biomarkers for diagnosing a heart attack. Heart muscle cells die off during a ... AB - Troponin T is one of the most commonly used biomarkers for diagnosing a heart attack. Heart muscle cells die off during a ... Troponin T is one of the most commonly used biomarkers for diagnosing a heart attack. Heart muscle cells die off during a heart ... abstract = "Troponin T is one of the most commonly used biomarkers for diagnosing a heart attack. Heart muscle cells die off ...
This test measures the amount of the protein troponin in your blood. It can tell your healthcare provider whether you are ... Troponin. Does this test have other names?. Cardiac troponin (cTn), cardiac troponin I (cTnI), cardiac troponin T (cTnT), high- ... High-sensitivity cardiac troponin (hs-cTn). High-sensitivity cardiac troponin is a newer type of testing that can detect lower ... Troponin is found in cells in your heart muscle. When these cells are injured, they can release troponin and other substances ...
Troponin I is a part of the troponin complex. It binds to actin in thin myofilaments to hold the troponin-tropomyosin complex ... Cardiac troponin I, TNNI3 (19q13.4, 191044). External links. *Troponin+I at the US National Library of Medicine Medical Subject ... Slow-twitch skeletal muscle isoform troponin I, TNNI1 (1q31.3, 191042). *Fast-twitch skeletal muscle isoform troponin I, TNNI2 ... Retrieved from "" ...
Reducing delays in troponin testing has been reported to result in shorter length of stay in the ED and more rapid initiation ... Rapid serum troponin measurement is an important part of ED practice that can provide decisive information for patient ... Six days per month, collect data from nine patients presenting to the ED with chest pain and tested for troponin level. Data ... The American College of Cardiology and the American Heart Association recommend troponin as the preferred diagnostic biomarker ...
Reducing delays in troponin testing has been reported to result in shorter length of stay in the ED and more rapid initiation ... Rapid serum troponin measurement is an important part of ED practice that can provide decisive information for patient ... Six days per month, collect data from nine patients presenting to the ED with chest pain and tested for troponin level. Data ... The American College of Cardiology and the American Heart Association recommend troponin as the preferred diagnostic biomarker ...
The epitope specificity for this MAb is 83 - 100 a.a.r. of human cardiac troponin I. Based on our results, the pair Y302 + ... We have launched a new troponin product MAb Y302 (Cat# RC4T21) recombinant monoclonal antibody to enable our customers develop ...
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  • Since the initial 1st-generation assays, 5th-generation high-sensitivity cardiac troponin (hs-cTn) assays have been developed, and are now widely used. (
  • Singulex has received the CE mark for its Sgx Clarity cTnI assay, an ultra-sensitive test that measures cardiac troponin at lower levels than most existing assays. (
  • The very recent commercialization of methods with further improved analytical sensitivity (i.e., "ultra-sensitive" assays), which allow to measure cardiac troponin values in the vast majority of healthy subjects, is now challenging the diagnostic paradigm based on early rule-out of subjects with cardiac troponin values comprised between the 99th percentile and LoD. (
  • Recent approvals of high sensitivity cardiac troponin (hs-cTn) assays by the U.S. Food and Drug Administration (FDA) and international regulatory bodies have enabled clinical labs to develop more sophisticated diagnostic protocols based on utilization of low cTn measurements at or near the assays' limit of detection (LoD) to expediate and improve the accuracy of acute myocardial infarction diagnosis. (
  • Non-high sensitivity cardiac troponin assays lack the analytical sensitivity to reliably measure small cTn concentrations and their subsequent changes below the 99th percentile upper reference limit (URL). (
  • Assays for hs-cTnI and hs-cTnT have allowed clinical labs to shift emphasis from using cardiac troponin as binary tests (in which the 99th percentile URL of a healthy reference population was used as a cut-off for defining normal vs increased cTn values) to more complex diagnostic protocols utilizing cTn values below the 99th percentiles' URLs. (
  • Scheitz JF, Nolte CH, Laufs U, Endres M. Application and interpretation of high-sensitivity cardiac troponin assays in patients with acute ischemic stroke. (
  • Even when cardiac troponin levels detected by high-sensitivity assays are within the normal range, elevations are associated with incident cardiovascular events in people without overt disease, a meta-analysis confirms. (
  • Adding information from high-sensitivity troponin assays to models that included conventional risk factors improved prediction of cardiovascular events, particularly fatal ones, suggesting a possible role for the tests in a primary prevention setting, the researchers say. (
  • Although cardiac troponins have been measured for years for diagnosing acute MI, the introduction of high-sensitivity assays-including just recently in the United States -has allowed for detection of very low levels, even in people without obvious signs of myocardial damage or cardiovascular disease. (
  • With the introduction of high-sensitivity cardiac troponin (hs-cTn) assays, the time it takes to detect signs of myocyte necrosis has shortened considerably. (
  • Ninety-Minute vs 3-h Performance of High-Sensitivity Cardiac Troponin Assays for Predicting Hospitalization for Acute Coronary Syndrome. (
  • Troponins are generally undetectable in healthy patients, although this may eventually change as more sensitive assays become available. (
  • The 99th percentile of a reference decision limit (medical decision cutoff) for cardiac troponin (cTn) assays should be determined in each local laboratory with internal studies using the specific assay that is used in clinical practice or validating a reference interval that is based on findings in the literature. (
  • Table 1 shows the calculated 99th upper reference limit values for some of the available troponin assays. (
  • When measured with older generation assays, elevated troponin levels can be detected 6-12 hours after onset of myocardial injury, peaking at about 24 hours, followed by a gradual decline over several days (up to 2 weeks). (
  • Most patients who have had a heart attack have increased troponin levels within 6 hours. (
  • Cardiac troponins (cTn), cardiac troponin I (cTnI) and cardiac troponin T (cTnT), are important analytes for acute myocardial infarction diagnosis and are used to guide treatment and patient management decisions. (
  • The use of troponin T (cTnT) and N-terminal Pro-BNP (NTpBNP) in combination with echocardiography assessment may facilitate the development of a superior predictive model. (
  • The 99th percentile cutoff point for cardiac troponin T (cTnT) is well-known at 0.01 ng/mL (with 10% coefficient of variance value at the 99th percentile of 0.03 ng/mL), as only one cTnT assay exists. (
  • Inside the cardiac troponin complex the strongest interaction between molecules has been demonstrated for cTnI - TnC binary complex especially in the presence of Ca2+ ( KA = 1.5 × 10−8 M−1). (
  • It has been demonstrated that stability of cTnI in native complex is significantly better than stability of the purified form of the protein or the stability of cTnI in artificial troponin complexes combined from purified proteins. (
  • Evaluation with serum cardiac troponin I (CTnI), a specific indicator of myocardial injury, could improve the comprehensive evaluation of patients with suspected NAT. (
  • Under 2020 och 21 införs inom Region Skåne en ny högkänslig blodprovsanalys för troponin I (hs-cTnI) som kan avslöja hjärtskada eller hjärtinfarkt. (
  • Phosphorylation levels of cardiac troponin I (cTnI) were determined by Western blot. (
  • The US Food and Drug Administration (FDA) has approved the Architect Stat (Abbott Laboratories) high-sensitivity troponin-I assay, which can detect myocardial infarction (MI) faster and more accurately than other troponin tests, according to the company. (
  • The addition of Abbott's high sensitivity troponin-I assay to the laboratory's diagnostic testing menu is a great step forward to help laboratory scientists and clinicians better evaluate patients suspected of having a heart attack," Fred Apple, PhD, professor of laboratory medicine and pathology at the University of Minnesota in Minneapolis, said in the release. (
  • A recent publication has shown that cardiac troponin T (TnT) concentrations measured with a highly sensitive assay were significantly associated with the incidence of cardiovascular death and heart failure in stable coronary artery disease after adjustment for other independent prognostic indicators [ 13 ]. (
  • With the increased clinical utility of sub-99th percentile hs-cTn measurements, quality controls with lower cardiac troponin concentrations are needed to monitor and validate hs-cTn assay performance. (
  • 99thpercentiles for cardiac troponin assay methods addressed in this article are greater than their respective assay methods' LoB, LoD, and LoQ. (
  • Hs-troponin I (Siemens), TNIH assay, was measured using the Siemens Centaur XP. (
  • For hs-troponin T (Roche) and hs-troponin I (Ortho), low values were initially blinded for each assay. (
  • Blood troponin levels may be used as a diagnostic marker for stroke or other myocardial injury that is ongoing, although the sensitivity of this measurement is low. (
  • Some labs use different measurements (for example, "high sensitivity troponin test") or test different samples. (
  • Perioperative myocardial injury, reflected by release of high-sensitivity cardiac troponin T, is associated with 30-day mortality after various cardiac surgeries at postoperative prognostic cutoffs higher than proposed in current definitions, new research suggests. (
  • They note that the current diagnostic criteria for perioperative myocardial infarction /injury "need to be updated with these high-sensitivity cardiac troponin data. (
  • The statistical method used to determine cardiac troponin values may have resulted in thresholds with a lower sensitivity. (
  • Cite this: FDA Clears Architect Stat High-Sensitivity Troponin Test for MI - Medscape - Oct 02, 2019. (
  • High-sensitivity cardiac troponin. (
  • The aim of this article is to provide an update on commercially available HS and "ultra"-sensitive techniques for measuring cardiac troponins, along with possible implications of increasingly enhanced analytical sensitivity on diagnostic algorithms for evaluating patients with suspected ACS. (
  • 2 However, high-sensitivity troponin is elevated in 20-55% of acute stroke patients, 3 many of whom without thrombotic acute coronary syndrome (ACS). (
  • The meta-analysis included 28 prospective studies with a total of 154,052 participants free from cardiovascular disease who underwent high-sensitivity troponin testing. (
  • Despite the results, it would be premature to advocate high-sensitivity troponin testing in broad swaths of the population, according to Ho. (
  • High-sensitivity cardiac troponin at 3 hours: is the cat among the pigeons? (
  • Rapid rule-out of acute myocardial infarction with a single high-sensitivity cardiac troponin T measurement below the limit of detection. (
  • During the past decade a number of new analysis have been studied and their respective performance have been documented which include myoglobin, CK isoform, myosin light chain, troponin T and troponin I. Sensitivity is not a major concern but specificity is a problem because the standard markers are not restricted to heart. (
  • High-Sensitivity Troponin at the point of care or lab? (
  • The value of high-sensitivity troponin I in the assessment of patients with suspected acute coronary syndrome (ACS) has been well established in clinical practice guidelines. (
  • This webinar will cover the utilization of high-sensitivity cardiac troponin (cTn) in the emergency department (ED) and its impact when delivered via a rapid point of care device or core laboratory. (
  • Low values of high-sensitivity cardiac troponin and coronary artery calcium scores of zero are associated with a low risk for atherosclerotic cardiovascular disease (or ASCVD). (
  • To better understand the relationship between these measurements and future ASCVD risk, a group of researchers evaluated baseline high-sensitivity cardiac troponin and CAC measurements taken from 6749 participants in the MESA study. (
  • Your analysis found that detectable CAC and detectable high-sensitivity cardiac troponin was associated with higher rates of ASCVD, compared to undetectable levels. (
  • Sera from stored surplus specimens in the NHANES 1999-2004 cycles were tested for high-sensitivity (hs)-troponin T (Roche), hs-troponin I (Abbott), hs-troponin I (Siemens) and hs-troponin I (Ortho). (
  • The results for high-sensitivity cardiac troponin in this data release are reported in nanograms per liter (ng/L). (
  • Associations of High-Sensitivity Troponin and Natriuretic Peptide Levels With Outcomes After Intensive Blood Pressure Lowering: Findings From the SPRINT Randomized Clinical Trial. (
  • Importance Elevated high- sensitivity cardiac troponin T (hscTnT) and N-terminal pro- B-type natriuretic peptide (NTproBNP) levels are associated with risk of heart failure (HF) and mortality among individuals in the general population . (
  • sensitivity cardiac troponin T and NTproBNP levels were measured from stored specimens collected at enrollment, with elevated levels defined as 14 ng/L or more for hscTnT (to convert to micrograms per liter, multiply by 0.001) and 125 pg/mL or more for NTproBNP (to convert to nanograms per liter, multiply by 1.0). (
  • Troponin, or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that are integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle. (
  • Troponin is found in both skeletal muscle and cardiac muscle, but the specific versions of troponin differ between types of muscle. (
  • The main difference is that the TnC subunit of troponin in skeletal muscle has four calcium ion-binding sites, whereas in cardiac muscle there are only three. (
  • The gene for the sarcomeric thin-filament protein, slow skeletal muscle troponin T (TNNT1), maps to this interval and was sequenced. (
  • The objective of this study was to compare the levels of troponin T and enzymes levels in myocardial infarction and skeletal muscle injury. (
  • There is no increase in troponin T levels in skeletal muscle injury. (
  • Troponins are protein molecules that are part of cardiac and skeletal muscle. (
  • Learn about the methods used to measure cardiac troponin, a protein released into the bloodstream during a heart attack, and the benefits of sensitive new technologies for earlier detection in the emergency department. (
  • The level of troponin is measured in the bloodstream and it is used to differentiate between unstable angina (no elevation of troponin, the myocardium is not irreversibly damaged) versus either non ST elevation MI or ST elevation MI (heart attack) in patients with chest pain . (
  • however, elevation of troponin levels can occur in myriad conditions other than ischemic damage. (
  • With respect to high prognostic relevance, 1 international guidelines recommend the measurement of troponin in all patients presenting with acute ischemic stroke. (
  • Numerous studies have identified a relationship between troponin levels and first-ever cardiovascular events in the general population, so Willeit and colleagues set out to provide an overall estimate of the association. (
  • METHODS: Using data collected in the American Heart Association's 'Get With The Guidelines' stroke registry between 2008 and 2012 at a tertiary care US hospital, we used logistic regression to evaluate the independent relationship between troponin elevation and mortality after adjusting for demographic and clinical characteristics. (
  • Cardiovascular and non‐cardiovascular death distinction: the utility of troponin beyond N‐terminal pro‐B‐type natriuretic peptide. (
  • The best model to predict CV death included low blood pressure, estimated glomerular filtration rate ≤ 60 mL/min, peripheral oedema, previous HF hospitalization, ischaemic HF, chronic obstructive pulmonary disease, elevated N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), and troponin (c‐index = 0.73). (
  • N-terminal B-type natriuretic peptide or troponin elevations, or the Background use of inotropes during admission, are much more powerful and Risk stratification and prediction is an integral part of clinical accurate predictors than admission to hospital alone. (
  • We then assessed whether the magnitude of troponin elevation was related to in-hospital mortality by calculating mortality rates according to tertiles of peak troponin levels. (
  • Any troponin elevation was associated with higher mortality, even at very low peak troponin levels (mortality rates 24-29% across tertiles of troponin). (
  • Objective: The aim of this investigation was to determine if the presence of ischemic electrocardiographic (ECG) changes in patients undergoing vascular surgery provides incremental prognostic information about the long-term risk of death compared with a single peak troponin level within 48 hours after surgery. (
  • Serum troponin (Tn) elevation is a specific and well-established necrosis biomarker in ACS, being the only biomarker currently used for risk stratification and guided invasive management decision in non-STEACS [ 8 , 9 ]. (
  • The purpose of this study was to examine whether the combination of two simple tests, electrocardiography (ECG) and serum troponin I (TnI) level, may serve as reliable predictors of BCI or the absence of it. (
  • Rapid serum troponin measurement is an important part of ED practice that can provide decisive information for patient management. (
  • Having normal troponin levels 12 hours after chest pain has started means a heart attack is unlikely. (
  • Serum cardiac troponin I and cardiac troponin T concentrations in dogs with gastric dilatation-volvulus. (
  • Very low concentrations of hs-troponin are associated with greater variability and are not routinely reported for clinical use. (
  • Conclusions The use of troponin as a diagnostic test and risk stratification tool appears to be used universally in England. (
  • However, the further risk stratification of patients presenting with acute chest pain without a rise in cardiac troponin is inconsistent. (
  • Atherosclerotic cardiovascular disease risk stratification based on measurements of troponin and coronary artery calcium. (
  • Troponin is a simple yet potent tool for risk stratification. (
  • Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. (
  • citation needed] Troponin is a component of thin filaments (along with actin and tropomyosin), and is the protein complex to which calcium binds to trigger the production of muscular force. (
  • Cardiac Troponin I (Cardiac-specific troponin I, TnI, Troponin I) is an integral inhibitory protein in cardiac muscle that exists as part of a complex with troponin C (TnC) and troponin T (TnT). (
  • The EMIT-test for Troponin T - a protein of the myocardial troponin complex - is nowadays of the great diagnostic value. (
  • Troponin is a component of thin filaments (along with actin and tropomyosin ), and is the protein to which calcium binds to accomplish this regulation. (
  • Elevated troponin in acute ischemic stroke - a matter of debate? (
  • This question was addressed by the Troponin Elevation in Acute Ischemic Stroke (TRELAS) study, which included 2123 consecutive patients presenting with acute ischemic stroke, who did not have ST-segment-elevation myocardial infarction (STEMI). (
  • The recently launched Prediction of Acute Coronary Syndrome in Acute Ischemic Stroke (PRAISE) study aims to develop a diagnostic algorithm that allows the prediction of acute coronary syndrome in stroke patients with elevated troponin. (
  • So, elevated troponin in acute ischemic stroke remains a matter of debate! (
  • Jensen JK, Atar D, Mickley H. Mechanism of troponin elevations in patients with acute ischemic stroke. (
  • Coronary Angiographic Findings in Acute Ischemic Stroke Patients With Elevated Cardiac Troponin: The Troponin Elevation in Acute Ischemic Stroke (TRELAS) Study. (
  • Scholars@Duke publication: Ischemic Stroke with Troponin Elevation: Patient Characteristics, Resource Utilization, and In-Hospital Outcomes. (
  • BACKGROUND: Among patients hospitalized for acute ischemic stroke, abnormal serum troponins are associated with higher risk of short-term mortality. (
  • RESULTS: Of 1,145 ischemic stroke patients, 199 (17%) had elevated troponin levels. (
  • CONCLUSIONS: Ischemic stroke patients with abnormal troponin levels are at higher risk of in-hospital death, even after accounting for demographic and clinical characteristics, and any degree of troponin elevation identifies this higher level of risk. (
  • If a patient is troponin positive, and has signs and symptoms of ischemic heart disease (substernal chest pain or pressure, electrocardiographic EKG changes), then an early invasive strategy is warranted. (
  • Reducing delays in troponin testing has been reported to result in shorter length of stay in the ED and more rapid initiation of anti-ischemic treatment. (
  • For PCI in patients with normal baseline troponin values, elevations of cardiac biomarkers above the 99th percentile upper reference limit indicate periprocedural myocardial necrosis. (
  • A troponin test measures the levels of troponin T or troponin I proteins in the blood. (
  • Cardiac troponin levels are normally so low they cannot be detected with most blood tests. (
  • Very high levels of troponin are a sign that a heart attack has occurred. (
  • Troponin levels may remain high for 1 to 2 weeks after a heart attack. (
  • The Architect Stat test detects very low levels of troponin, allowing clinicians to assess patients with suspected MI within 2 to 4 hours of admission, the company said. (
  • Women may particularly benefit from this technology as they often have lower levels of troponin than men, which could lead to an undiagnosed heart attack with contemporary troponin tests," they add in a news release . (
  • Even though we see this very strong association of troponin levels with cardiovascular risk, it still is unclear and remains unknown how we would potentially modify that risk and how we would change our approach based on having a troponin laboratory value as part of your usual clinical assessment," she said. (
  • First, there are no primary prevention trials similar to those done for statins to show that targeting patients with elevated troponin levels can improve outcomes. (
  • There's also uncertainty about the source of the raised troponin levels in people without clinically apparent disease. (
  • Patients with suspected acute coronary syndromes and negative cardiac troponin (cTn) levels are deemed at low risk. (
  • Patients with persistently rising troponin levels had fewer anticoagulant and antiatherosclerotic therapies, with markedly worse outcomes. (
  • Cardiac troponin I level was elevated in 7 (70%) of 10 patients with levels between 2 and 50 times the upper limit of normal. (
  • In this podcast, Michael Blaha, MD, MPH, discusses his team's study on whether troponin levels and coronary artery calcium score can predict future atherosclerotic cardiovascular disease risk, the use of aspirin and statins in patients aged 50 to 79 years, and his team's future work in this area. (
  • I don't think it would surprise anyone that higher levels of troponin and higher levels of calcium scores predict risk. (
  • What was also notable is that undetectable levels of troponin or calcium scores of zero also predicted extremely low-risk states. (
  • Violin plots show distribution of expression levels for Troponin I (SMED30021982) in cells (dots) of each of the 12 neoblast clusters. (
  • Violin plots show distribution of expression levels for Troponin I (SMED30021982) in cells (dots) of each of the 10 clusters of sub-leathally irradiated X1 and X2 cells. (
  • Troponin T is an early indicator of myocardial infarction and is superior to CKMB in diagnosis of myocardial injury. (
  • The actual amount of calcium that binds to troponin has not been definitively established. (
  • citation needed] Individual subunits serve different functions:[citation needed] Troponin C binds to calcium ions to produce a conformational change in TnI Troponin T binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex Troponin I binds to actin in thin myofilaments to hold the actin-tropomyosin complex in place Smooth muscle does not have troponin. (
  • The TnT subunit of troponin binds to tropomyosin-t form, a troponin-tropomyosin complex, anchored in place by the binding of TnI to actin, within muscle thin filaments. (
  • Three types of troponins exist-troponin I, troponin T, and troponin C. Each subunit has a unique function: Troponin T binds the troponin components to tropomyosin, troponin I inhibits the interaction of myosin with actin, and troponin C contains the binding sites for Ca 2+ that helps initiate contraction. (
  • The aim of this study was to evaluate the potential utility of genetic diagnosis in clinical management of families with hypertrophic cardiomyopathy (HCM) caused by mutations in the gene for cardiac troponin I (TNNI3). (
  • Mutations in the Cardiac Troponin I gene cause familial hypertrophic cardiomyopathy type 7 (CMH7) and familial restrictive cardiomyopathy (RCM). (
  • The following product was used in this experiment: Cardiac Troponin I Monoclonal Antibody (1D5D6), CoraLite®Plus 488 from Thermo Fisher Scientific, catalog # CL488-66376. (
  • Human IgG antibody Laboratories manufactures the is troponin test a stat reagents distributed by Genprice. (
  • The role of cardiac troponins as diagnostic biomarkers of myocardial injury in the context of acute coronary syndrome (ACS) is well established. (
  • Measurements of cardiac-specific troponins I and T are extensively used as diagnostic and prognostic indicators in the management of myocardial infarction and acute coronary syndrome. (
  • 5 Of all included patients, a subset of 29 of 291 patients with elevated troponin underwent diagnostic coronary angiography. (
  • The total level and the dynamic of the troponin increase may help to predict myocardial infarction, 6 but eventually, the diagnostic work up and treatment of individual patients remains a matter of debate between neurologists and cardiologists. (
  • Discussions of troponin often pertain to its functional characteristics and/or to its usefulness as a diagnostic marker for various heart disorders. (
  • The American College of Cardiology and the American Heart Association recommend troponin as the preferred diagnostic biomarker in their Acute Coronary Syndromes guideline. (
  • Cardiac troponins are components of the contractile apparatus of cardiomyocytes and are released during myocardial necrosis in patients with ACS [ 7 ]. (
  • If the injury persists and necrosis progresses, further troponins are released from the muscular pool. (
  • See also Acute coronary syndromes Two subtypes of troponin (cardiac troponin I and T) are very sensitive and specific indicators of damage to the heart muscle ( myocardium ). (
  • The greatest advantage of Troponin T is its unique specificity that is close to 100 per cent. (
  • Background Patients presenting with acute chest pain without a rise in cardiac troponins are considered to be at low risk of adverse cardiac events and are often considered for early discharge without further inpatient investigation. (
  • One of the more common uses of troponin is to determine if a patient with chest pain has sustained death of the myocytes (heart muscle cells) as a result of thrombotic (blood clot related) occlusion of a coronary artery which would warrant urgent medical or interventional therapy. (
  • EDs and chest pain centers should, therefore, have effective procedures for ensuring optimal turnaround time (TAT) for troponin testing and a process for ongoing monitoring to ensure that performance meets expectations. (
  • Six days per month, collect data from nine patients presenting to the ED with chest pain and tested for troponin level. (
  • It has been shown that even very small elevation in the troponin concentration is associated with increased risk of adverse outcomes in patients with ACS [ 12 ]. (
  • Canine Cardiac Troponin I Significantly Complements Established Prognostic Composite Score In Dogs With Systemic Inflammation. (
  • And really thinking here was to figure out how each marker performed-the troponin and the calcium score-for risk prediction and how they perform together, with a distinct emphasis on low values of each marker-undetectable troponin values and calcium scores of zero-and to what degree those can discriminate patients that are actually low-risk patients. (
  • Calcium score and undetectable troponins were associated event rates that were lower than the usual threshold considered for a statin benefit or aspirin benefit in primary prevention. (
  • So, the study would suggest that the event rates in patients with undetectable troponin or calcium scores of zero are below which we'd expect there to be a net benefit of preventive pharmacotherapy. (
  • But what's notable also is that when you do a 2 × 2 cross tab of these markers, patients who had both undetectable troponin and a calcium score of zero had the lowest event rates on the order of 2% or 3% over 10 years, which is very low. (
  • When asked about the most likely mechanisms to explain the link between modestly elevated troponins and cardiovascular events, Willeit pointed to subclinical coronary atherosclerosis, cardiac stress, and cardiac abnormalities that have not yet been detected. (
  • That more than three-quarters of participants without obvious cardiovascular disease have detectable troponin is "pretty striking," she added. (
  • Troponin-positive patients had more cardiovascular risk factors, more intensive medical therapy, and greater use of cardiac procedures. (
  • An initial small elevation occurs when troponins are released from the cytosolic pool, when troponin molecules in the cytosol of cardiac muscle diffuse across the sarcolemma into the surrounding lymphatics and blood vessels, becoming detectable in blood. (
  • Some of this calcium attaches to troponin, causing a conformational change that moves tropomyosin out of the way so that the cross bridges can attach to actin and produce muscle contraction. (
  • 4 Further conditions frequently associated with elevated troponin include atrial fibrillation, heart failure, pulmonary embolism, sepsis, and renal insufficiency. (
  • The measurement of cardiac troponins, either cardiac troponin I or T, has become the culprit of clinical decision making in patients with suspected acute coronary syndrome (ACS), especially in those with non-ST elevation myocardial infarction (NSTEMI). (
  • 5 Nonetheless, coronary culprit lesions were identified in 24% of stroke patients with elevated troponin, thus demonstrating that elevated troponin should not be ignored in acute stroke patients. (
  • The hope is that a marker like troponin could be used to identify people who have subclinical disease and it could help target preventive interventions," Willeit told TCTMD. (
  • More recently, troponin sub-units I or T, have been used as an even more specific marker of myonecrosis. (
  • This review discusses troponin as a marker of cardiac injury, its testing, utility, appropriateness use criteria, and interpretation of abnormal values. (
  • Some of this calcium attaches to troponin, which causes it to change shape, exposing binding sites for myosin (active sites) on the actin filaments. (
  • Creatine kinase, aspartate amino-transferase, lactate dehydrogenase and Troponin T were determined by kit methods. (
  • Participants will also complete a questionnaire about clinical and laboratory practices related to troponin testing. (
  • Even a slight increase in the troponin level will often mean there has been some damage to the heart. (
  • Willeit agreed, saying more research, including meta-analyses with patient-level rather than study-level data, needs to be performed before making any recommendations regarding expansive troponin testing. (
  • Troponin T appears in blood a little earlier that CK-MB, two and a half hours after the onset of the heart attack, reaches its maximum in 8-10 hours (the first peak) and in 3-4 days (the second peak), and its level becomes standard in 10-14 days. (
  • The standard level of Troponin T must be close to zero because it should not get into the blood flow with healthy people. (
  • Elevated cardiac troponin I level in cases of thoracic nonaccidental trauma. (
  • 99th percentiles for cardiac Troponin I and T are often used as cut-off values for diagnosing AMI. (
  • Serum values of cardiac troponin T in normal and cardiomyopathic dogs, Vet. (
  • To better understand whether troponin elevation identified patients most likely to die due to a specific cause of death, investigators blinded from troponin values reviewed all in-hospital deaths, and the association between troponin elevation and mortality was evaluated among patients with cardiac, neurologic, or other causes of death. (
  • Peak cardiac troponin (cTn) I values that exceeded the upper reference limit (URL) were categorized as low-positive (+), at or exceeding the URL but less than three times the URL, or high-positive (+), at or exceeding three times the URL. (
  • The hs-troponin I (Siemens) was initially blinded at values below the limit of quantitation (LoQ). (