Isomerism: The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Heterotaxy Syndrome: Abnormal thoracoabdominal VISCERA arrangement (visceral heterotaxy) or malformation that involves additional CONGENITAL HEART DEFECTS (e.g., heart isomerism; DEXTROCARDIA) and/or abnormal SPLEEN (e.g., asplenia and polysplenia). Irregularities with the central nervous system, the skeleton and urinary tract are often associated with the syndrome.Heart Defects, Congenital: Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.Situs Inversus: A congenital abnormality in which organs in the THORAX and the ABDOMEN are opposite to their normal positions (situs solitus) due to lateral transposition. Normally the STOMACH and SPLEEN are on the left, LIVER on the right, the three-lobed right lung is on the right, and the two-lobed left lung on the left. Situs inversus has a familial pattern and has been associated with a number of genes related to microtubule-associated proteins.Heart Septal Defects: Abnormalities in any part of the HEART SEPTUM resulting in abnormal communication between the left and the right chambers of the heart. The abnormal blood flow inside the heart may be caused by defects in the ATRIAL SEPTUM, the VENTRICULAR SEPTUM, or both.Abnormalities, MultipleVenae Cavae: The inferior and superior venae cavae.Dextrocardia: A congenital defect in which the heart is located on the right side of the THORAX instead of on the left side (levocardia, the normal position). When dextrocardia is accompanied with inverted HEART ATRIA, a right-sided STOMACH, and a left-sided LIVER, the combination is called dextrocardia with SITUS INVERSUS. Dextrocardia may adversely affect other thoracic organs.Levocardia: Congenital abnormalities in which the HEART is in the normal position (levocardia) in the left side of the chest but some or all of the THORAX or ABDOMEN viscera are transposed laterally (SITUS INVERSUS). It is also known as situs inversus with levocardia, or isolated levocardia. This condition is often associated with severe heart defects and splenic abnormalities such as asplenia or polysplenia.Heart Bypass, Right: Diversion of the flow of blood from the entrance to the right atrium directly to the pulmonary arteries, avoiding the right atrium and right ventricle (Dorland, 28th ed). This a permanent procedure often performed to bypass a congenitally deformed right atrium or right ventricle.Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Erythrocruorins: High molecular weight (1,500,000 to 3,000,000) hemoglobins found in the plasma of many polychete and oligochete annelid worms and various mollusks. They bind one mole of oxygen per heme and function as oxygen carriers.Pulmonary Veno-Occlusive Disease: Pathological process resulting in the fibrous obstruction of the small- and medium-sized PULMONARY VEINS and PULMONARY HYPERTENSION. Veno-occlusion can arise from fibrous proliferation of the VASCULAR INTIMA and VASCULAR MEDIA; THROMBOSIS; or a combination of both.Growth Differentiation Factor 1: A growth differentiation factor that plays a role in the genesis of left-right asymmetry during vertebrate development. Evidence for this role is seen in MICE where loss of growth differentiation factor 1 function results in right-left isomerism of visceral organs. In HUMANS heterozygous loss of growth differentiation factor 1 function has been associated with CONGENITAL HEART DEFECTS and TRANSPOSITION OF GREAT VESSELS.Fetal Heart: The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.Cyanosis: A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule.Abortion, Eugenic: Abortion performed because of possible fetal defects.Nodal Protein: The founding member of the nodal signaling ligand family of proteins. Nodal protein was originally discovered in the region of the mouse embryo primitive streak referred to as HENSEN'S NODE. It is expressed asymmetrically on the left side in chordates and plays a critical role in the genesis of left-right asymmetry during vertebrate development.Atrioventricular Node: A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.Fetal Diseases: Pathophysiological conditions of the FETUS in the UTERUS. Some fetal diseases may be treated with FETAL THERAPIES.Vena Cava, Inferior: The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.Fontan Procedure: A procedure in which total right atrial or total caval blood flow is channeled directly into the pulmonary artery or into a small right ventricle that serves only as a conduit. The principal congenital malformations for which this operation is useful are TRICUSPID ATRESIA and single ventricle with pulmonary stenosis.Azygos Vein: A vein which arises from the right ascending lumbar vein or the vena cava, enters the thorax through the aortic orifice in the diaphragm, and terminates in the superior vena cava.Tachycardia, Supraventricular: A generic expression for any tachycardia that originates above the BUNDLE OF HIS.Sinoatrial Node: The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).Heart Block: Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects.Ultrasonography, Prenatal: The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.Heart Valves: Flaps of tissue that prevent regurgitation of BLOOD from the HEART VENTRICLES to the HEART ATRIA or from the PULMONARY ARTERIES or AORTA to the ventricles.Atrial Appendage: Ear-shaped appendage of either atrium of the heart. (Dorland, 28th ed)Heart Septal Defects, Atrial: Developmental abnormalities in any portion of the ATRIAL SEPTUM resulting in abnormal communications between the two upper chambers of the heart. Classification of atrial septal defects is based on location of the communication and types of incomplete fusion of atrial septa with the ENDOCARDIAL CUSHIONS in the fetal heart. They include ostium primum, ostium secundum, sinus venosus, and coronary sinus defects.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Proline: A non-essential amino acid that is synthesized from GLUTAMIC ACID. It is an essential component of COLLAGEN and is important for proper functioning of joints and tendons.Prenatal Diagnosis: Determination of the nature of a pathological condition or disease in the postimplantation EMBRYO; FETUS; or pregnant female before birth.Infant, Newborn: An infant during the first month after birth.Syndrome: A characteristic symptom complex.Body Patterning: The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.Asia: The largest of the continents. It was known to the Romans more specifically as what we know today as Asia Minor. The name comes from at least two possible sources: from the Assyrian asu (to rise) or from the Sanskrit usa (dawn), both with reference to its being the land of the rising sun, i.e., eastern as opposed to Europe, to the west. (From Webster's New Geographical Dictionary, 1988, p82 & Room, Brewer's Dictionary of Names, 1992, p34)Gestational Age: The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Spleen: An encapsulated lymphatic organ through which venous blood filters.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Stomach: An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Protein Conformation: 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).Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Time Factors: Elements of limited time intervals, contributing to particular results or situations.

Anaerobic degradation of phthalate isomers by methanogenic consortia. (1/3124)

Three methanogenic enrichment cultures, grown on ortho-phthalate, iso-phthalate, or terephthalate were obtained from digested sewage sludge or methanogenic granular sludge. Cultures grown on one of the phthalate isomers were not capable of degrading the other phthalate isomers. All three cultures had the ability to degrade benzoate. Maximum specific growth rates (microseconds max) and biomass yields (YXtotS) of the mixed cultures were determined by using both the phthalate isomers and benzoate as substrates. Comparable values for these parameters were found for all three cultures. Values for microseconds max and YXtotS were higher for growth on benzoate compared to the phthalate isomers. Based on measured and estimated values for the microbial yield of the methanogens in the mixed culture, specific yields for the phthalate and benzoate fermenting organisms were calculated. A kinetic model, involving three microbial species, was developed to predict intermediate acetate and hydrogen accumulation and the final production of methane. Values for the ratio of the concentrations of methanogenic organisms, versus the phthalate isomer and benzoate fermenting organisms, and apparent half-saturation constants (KS) for the methanogens were calculated. By using this combination of measured and estimated parameter values, a reasonable description of intermediate accumulation and methane formation was obtained, with the initial concentration of phthalate fermenting organisms being the only variable. The energetic efficiency for growth of the fermenting organisms on the phthalate isomers was calculated to be significantly smaller than for growth on benzoate.  (+info)

Expression of alpha2-adrenergic receptors in rat primary afferent neurones after peripheral nerve injury or inflammation. (2/3124)

1. Immunocytochemistry with polyclonal antibodies directed against specific fragments of intracellular loops of alpha2A- and alpha2C-adrenergic receptors (alpha2A-AR, alpha2C-AR) was used to explore the possibility that expression of these receptors in dorsal root ganglion (DRG) neurones of rat alters as a result of peripheral nerve injury or localized inflammation. 2. Small numbers of neurones with positive alpha2A-AR immunoreactivity (alpha2A-AR-IR) were detected in DRG from normal animals or contralateral to nerve lesions. In contrast, after complete or partial sciatic nerve transection the numbers of ipsilateral L4 and L5 DRG somata expressing alpha2A-AR-IR sharply increased (>5-fold). There was no discernible change in the number of DRG neurones exhibiting alpha2A-AR-IR innervating a region in association with localized chemically induced inflammation. 3. After nerve injury, double labelling with Fluoro-Gold, a marker of retrograde transport from transected fibres, or by immunoreactivity for c-jun protein, an indicator of injury and regeneration, suggested that many of the neurones expressing alpha2A-AR-IR were uninjured by the sciatic lesions. 4. In general the largest proportionate increase in numbers of neurones labelled by alpha2A-AR-IR after nerve lesions appeared in the medium-large diameter range (31-40 microm), a group principally composed of cell bodies of low threshold mechanoreceptors. The number of small diameter DRG neurones labelled by alpha2A-AR-IR, a category likely to include somata of nociceptors, also increased but proportionately less. 5. Relatively few DRG neurones exhibited alpha2C-AR-IR; this population did not appear to change after either nerve lesions or inflammation. 6. These observations are considered in relation to effects of nerve injury on excitation of primary afferent neurones by sympathetic activity or adrenergic agents, sympathetically related neuropathy and reports of sprouting of sympathetic fibres in DRG.  (+info)

Structural identification of sulfated tyrosine in human urine. (3/3124)

A reliable HPLC method was used for the identification of positional isomerism and stereoisomerism of sulfated tyrosine residues in human urine. Upon separation of human urine by ion-pair HPLC on a reverse-phase column, p-tyrosine-O-sulfate (p-TyrS) was identified. Differentiation of the L and D forms was done by using a column with a chiral stationary phase. It was concluded that L-p-tyrosine (L-p-Tyr) which is the predominant tyrosine isomer in the human body, was sulfated and excreted in human urine as a normal constituent. The sulfated forms of D-p-Tyr and m-Tyr could not be detected under these analytical conditions.  (+info)

Metabolism of retinaldehyde isomers in pregnant rats: 13-cis- and all-trans-retinaldehyde, but not 9-cis-retinaldehyde, yield very similar patterns of retinoid metabolites. (4/3124)

Retinaldehyde (RAL), a key intermediate in retinoid metabolism, acts as a retinoic acid (RA) precursor, but is also reduced to retinol (ROH), which can subsequently be esterified to retinyl esters, the storage form of vitamin A. Limited information is available on the metabolism of geometric isomers of RAL as well as on the transplacental distribution of their metabolites, including RA isomers. Such information would be very helpful for the assessment of the teratogenic potency of RAL isomers, as teratogenesis represents a major side effect of retinoid use in pharmacotherapy. In the present study we examined concentrations of retinoids in plasma, maternal tissues, and embryos of pregnant rats 2 h after a single oral dose (100 mg/kg body weight) of all-trans-, 13-cis-, or 9-cis-RAL on gestational day 13. The main findings of this study were the very similar patterns of retinoid metabolites (consisting of retinoids with mainly the all-trans-configuration) after administration of all-trans- and 13-cis-RAL, and the high concentrations of 9-cis-RA, 9,13-dicis-RA, and 9-cis-retinoyl-beta-D-glucuronide after dosing with 9-cis-RAL. In addition, all-trans-RA as a RAL metabolite reached the embryos to a much greater extent than any of its cis-isomers. The results are discussed in view of in vitro data on enzymes involved in the biotransformation of RAL isomers.  (+info)

Substrate specificity of lysophospholipase D which produces bioactive lysophosphatidic acids in rat plasma. (5/3124)

Previously we reported that lysophospholipase D in rat plasma hydrolyzes endogenous unsaturated lysophosphatidylcholines (LPCs) preferentially to saturated LPCs to lysophosphatidic acids with growth factor-like and hormone-like activities. In this study, we examined the possibility that association of LPCs with different proteins in rat plasma has an effect on the preference of lysophospholipase D for unsaturated LPCs. Large portions of various LPCs were found to be recovered in the lipoprotein-poor bottom fraction. Furthermore, the percentages of LPCs associated with albumin isolated from rat plasma were shown not to be consistent with their percentage conversions to lysophosphatidic acids by lysophospholipase D on incubation of rat plasma at 37 degrees C. These results indicate that distinct distributions of LPCs in the plasma protein fractions are not critical factors for the substrate specificity of lysophospholipase D. Experiments with Nagase analbuminemic rats suggested that albumin-LPC complexes are not necessarily required for the hydrolysis by lysophospholipase D; lipoprotein-associate LPCs appeared to be good substrates for the phospholipase. We found that both saturated and unsaturated LPCs are present mainly as 1-acyl isomers in rat plasma. This result indicates that the preference of lysophospholipase D for unsaturated LPCs is not attributable to a difference in position of the acyl group attached to the glycerol backbone of LPC. In addition, lysophospholipase D was also found to attack choline phospholipids with a long chain group and a short chain alkyl group, although their percentage hydrolyses were low. Taken altogether, these results suggest that lysophospholipase D shows higher affinities for free forms of unsaturated acyl type LPCs equilibrated with albumin-bound and lipoprotein-associated forms, than for free forms of saturated acyl type LPCs and analogs of platelet-activating factor.  (+info)

Cloning and characterization of RGS9-2: a striatal-enriched alternatively spliced product of the RGS9 gene. (6/3124)

Regulators of G-protein signaling (RGS) proteins act as GTPase-activating proteins (GAPs) for alpha subunits of heterotrimeric G-proteins. Previous in situ hybridization analysis of mRNAs encoding RGS3-RGS11 revealed region-specific expression patterns in rat brain. RGS9 showed a particularly striking pattern of almost exclusive enrichment in striatum. In a parallel study, RGS9 cDNA, here referred to as RGS9-1, was cloned from retinal cDNA libraries, and the encoded protein was identified as a GAP for transducin (Galphat) in rod outer segments. In the present study we identify a novel splice variant of RGS9, RGS9-2, cloned from a mouse forebrain cDNA library, which encodes a striatal-specific isoform of the protein. RGS9-2 is 191 amino acids longer than the retinal isoform, has a unique 3' untranslated region, and is highly enriched in striatum, with much lower levels seen in other brain regions and no expression detectable in retina. Immunohistochemistry showed that RGS9-2 protein is restricted to striatal neuropil and absent in striatal terminal fields. The functional activity of RGS9-2 is supported by the finding that it, but not RGS9-1, dampens the Gi/o-coupled mu-opioid receptor response in vitro. Characterization of a bacterial artificial chromosome genomic clone of approximately 200 kb indicates that these isoforms represent alternatively spliced mRNAs from a single gene and that the RGS domain, conserved among all known RGS members, is encoded over three distinct exons. The distinct C-terminal domains of RGS9-2 and RGS9-1 presumably contribute to unique regulatory properties in the neural and retinal cells in which these proteins are selectively expressed.  (+info)

Cloning and characterization of a human electrogenic Na+-HCO-3 cotransporter isoform (hhNBC). (7/3124)

Our group recently cloned the electrogenic Na+-HCO-3 cotransporter (NBC) from salamander kidney and later from mammalian kidney. Here we report cloning an NBC isoform (hhNBC) from a human heart cDNA library. hhNBC is identical to human renal NBC (hkNBC), except for the amino terminus, where the first 85 amino acids in hhNBC replace the first 41 amino acids of hkNBC. About 50% of the amino acid residues in this unique amino terminus are charged, compared with approximately 22% for the corresponding 41 residues in hkNBC. Northern blot analysis, with the use of the unique 5' fragment of hhNBC as a probe, shows strong expression in pancreas and expression in heart and brain, although at much lower levels. In Xenopus oocytes expressing hhNBC, adding 1.5% CO2/10 mM HCO-3 hyperpolarizes the membrane and causes a rapid fall in intracellular pH (pHi), followed by a pHi recovery. Subsequent removal of Na+ causes a depolarization and a reduced rate of pHi recovery. Removal of Cl- from the bath does not affect the pHi recovery. The stilbene derivative DIDS (200 microM) greatly reduces the hyperpolarization caused by adding CO2/HCO-3. In oocytes expressing hkNBC, the effects of adding CO2/HCO-3 and then removing Na+ were similar to those observed in oocytes expressing hhNBC. We conclude that hhNBC is an electrogenic Na+-HCO-3 cotransporter and that hkNBC is also electrogenic.  (+info)

Splicing of a retained intron within ROMK K+ channel RNA generates a novel set of isoforms in rat kidney. (8/3124)

The renal outer medulla K+ channel (ROMK) family of K+ channels may constitute a major pathway for K+ secretion in the distal nephron. To date, four main isoforms of this gene have been identified in the rat that differ only in their NH2-terminal amino acids and that share a common "core exon" that determines the remaining protein sequence. Using RT-PCR, we have identified a new set of ROMK isoforms in rat kidney that are generated by the deletion of a region within the ROMK core sequence that is identifiable as a typical mammalian intron. This splicing event was shown to be reproducible in vitro by detection of deleted ROMK mRNA in Madin-Darby canine kidney (MDCK) cells stably transfected with the gene for ROMK2. Translation of the deletion variant of ROMK2 was confirmed in vitro and visualized in MDCK cells following transient transfection with an enhanced green fluorescent protein tag. The deletion in this core region is predicted to generate hydrophilic proteins that are approximately one-third of the size of native ROMK and lack membrane-spanning domains.  (+info)

  • Isomerism , the existence of molecules that have the same numbers of the same kinds of atoms (and hence the same formula) but differ in chemical and physical properties. (britannica.com)
  • It is not a physical isomerism like other structural isomers. (thelearningpoint.net)
  • Our results imply that layers with mismatched symmetries can join together in several different relative orientations, and that orientations at different interfaces assort independently to produce structural isomers, a process that we call combinatorial assembly isomerism. (pnas.org)
  • We report successful primary surgical repair of transposition of the great arteries (TGA) and complete atrioventricular septal defect (AVSD) associated with left isomerism {I,L,L} without pulmonary obstruction in a 1-month-old infant. (springermedizin.de)
  • To the best of our knowledge, this is the first report of successful primary surgical repair of TGA and AVSD with left isomerism. (springermedizin.de)
  • Primary anatomic correction of this defect combination is feasible in patients with left isomerism. (springermedizin.de)
  • Six children, aged 12 days to 13 years, with left isomerism and complete atrioventricular (A-V) block are presented. (elsevier.com)
  • In all six patients the diagnosis of left isomerism was suggested by an interrupted inferior vena cava found during cardiac catheterization and angiocardiography;four patients had complex heart disease consisting of endocardial cushion defect, five had a common atrium, three had pulmonary stenosis, three had patent ductus arteriosus and two had dextrocardia. (elsevier.com)
  • This report discusses the clinical presentation of complete A-V block and left isomerism and reviews the literature. (elsevier.com)
  • Heterotaxy, also referred to as isomerism of the atrial appendages, is defined as an abnormal assembly of the thoracic and abdominal organs from the normal arrangement known as 'situs solitus. (uptodate.com)
  • This topic will review the management and outcome of patients with heterotaxy (isomerism). (uptodate.com)
  • The anatomical variation, clinical manifestations, and diagnosis of heterotaxy (isomerism) are presented separately. (uptodate.com)
  • See 'Anatomy, clinical manifestations, and diagnosis of heterotaxy (isomerism of the atrial appendages)' . (uptodate.com)
  • Atrial isomerism is a major component of heterotaxy and causes significant morbidity and mortality because of discordance among the heart, systemic and pulmonary vessels, and other organs, and also among components of the heart. (uptodate.com)
  • See 'Anatomy, clinical manifestations, and diagnosis of heterotaxy (isomerism of the atrial appendages)', section on 'Right atrial isomerism' . (uptodate.com)
  • Right-atrial isomerism (RAI) is a heterotaxy syndrome with disturbances of left-right axis development resulting in complex heart malformations and anomalies of the thoracic and abdominal organs. (biomedsearch.com)
  • Session 7: What is Visceral Heterotaxy & Isomerism? (broadcastmed.com)
  • In Session 7 of the Pediatric Cardiac Morphology courses, Robert Anderson, MD, describes Visceral Heterotaxy and Isomerism Rings. (broadcastmed.com)
  • Heterotaxy syndromes can be further classified in two main subgroups, including right-sided isomerism and left-sided isomerism, often associated with asplenia and polysplenia, respectively. (biomedcentral.com)
  • Coordination isomerism is a form of structural isomerism in which the composition of the complex ion varies. (wikipedia.org)
  • Many different kinds of isomerism occur among coordination compounds. (britannica.com)
  • Schiff pentadentate ligands based on an [ON2Ocore displaying structural isomerism and their coordination to dibutyltin moieties. (edu.mx)
  • ROESY spectra were used to calculate the structure of 2a, which contained a single turn of a peptide alpha helix in both DMF and water, the helix being better defined in DMF The Pd(en)(2+) moiety was not used in structure calculations, but its location and coordination by one imidazole N1 from each histidine to form a 22-membered metallocycle were unambiguously established. (edu.au)
  • Since positional isomerism affects strongly its potency in inhibiting colon cancer cell growth, we studied the metabolic transformations of its ortho -, meta -, and para -isomers in rat liver and colon cytosolic, microsomal, and mitochondrial fractions as well as in intact HT-29 human colon cancer cells. (aspetjournals.org)
  • Thus, the three positional isomers of NO-ASA differ in their metabolism and these differences correlate with their differential effects on cancer cell growth, underscoring the importance of positional isomerism in modulating drug effects. (aspetjournals.org)
  • An interesting feature of NO-ASA is the effect of positional isomerism on its biological effects. (aspetjournals.org)
  • Positional isomerism markedly affects the growth inhibition of colon c" by Federica Vannini, Mitali Chattopadhyay et al. (cuny.edu)
  • From this App you can also learn about Isomerism of Organic Compounds. (edu.hk)
  • The term 'isomerism,' derived from Greek ( iso, meaning 'equal,' and meros , meaning 'part'), refers to this abnormal developmental symmetry in which morphologic structures that normally develop on one side or the other of the body are found on both sides of the body, and is the currently accepted term used to describe hearts with isomeric atria and atrial appendages [ 1 ]. (uptodate.com)