A compound used as an x-ray contrast medium that occurs in nature as the mineral barite. It is also used in various manufacturing applications and mixed into heavy concrete to serve as a radiation shield.
An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.
Inorganic compounds that contain barium as an integral part of the molecule.
A solution or compound that is introduced into the RECTUM with the purpose of cleansing the COLON or for diagnostic procedures.
An element of the alkaline earth family of metals. It has the atomic symbol Sr, atomic number 38, and atomic weight 87.62.
A pouch or sac opening from the COLON.
Endoscopic examination, therapy or surgery of the sigmoid flexure.
A genus of BROWN ALGAE in the family Lessoniaceae, and one of the major forms of KELP. The species Macrocystis pyrifera, also known as giant kelp, is the largest of the marine algae.
Pathological processes in the COLON region of the large intestine (INTESTINE, LARGE).
Endoscopic examination, therapy or surgery of the luminal surface of the colon.
Difficulty in SWALLOWING which may result from neuromuscular disorder or mechanical obstruction. Dysphagia is classified into two distinct types: oropharyngeal dysphagia due to malfunction of the PHARYNX and UPPER ESOPHAGEAL SPHINCTER; and esophageal dysphagia due to malfunction of the ESOPHAGUS.
Substances used to allow enhanced visualization of tissues.
A motility disorder of the ESOPHAGUS in which the LOWER ESOPHAGEAL SPHINCTER (near the CARDIA) fails to relax resulting in functional obstruction of the esophagus, and DYSPHAGIA. Achalasia is characterized by a grossly contorted and dilated esophagus (megaesophagus).
Unstable isotopes of barium that decay or disintegrate emitting radiation. Ba atoms with atomic weights 126-129, 131, 133, and 139-143 are radioactive barium isotopes.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Production of an image when x-rays strike a fluorescent screen.
STOMACH herniation located at or near the diaphragmatic opening for the ESOPHAGUS, the esophageal hiatus.
The act of taking solids and liquids into the GASTROINTESTINAL TRACT through the mouth and throat.
A genus of BROWN ALGAE in the family Laminariaceae. Dried pencil-like pieces may be inserted in the cervix where they swell as they absorb moisture, serving as osmotic dilators.
Measurement of the pressure or tension of liquids or gases with a manometer.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.
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.
Radiography of the gallbladder after ingestion of a contrast medium.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
A non-invasive imaging method that uses computed tomographic data combined with specialized imaging software to examine the colon.
Pathological processes in the ESOPHAGUS.
Bleeding in any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM.
Saccular protrusion beyond the wall of the ESOPHAGUS.
Identification and measurement of ELEMENTS and their location based on the fact that X-RAYS emitted by an element excited by an electron beam have a wavelength characteristic of that element and an intensity related to its concentration. It is performed with an electron microscope fitted with an x-ray spectrometer, in scanning or transmission mode.
Any impairment, arrest, or reversal of the normal flow of INTESTINAL CONTENTS toward the ANAL CANAL.
A versatile contrast medium used for DIAGNOSTIC X-RAY RADIOLOGY.
Chemical, spectroscopic, or microscopic detection of extremely small amounts of blood.
A diphenylmethane stimulant laxative used for the treatment of CONSTIPATION and for bowel evacuation. (From Martindale, The Extra Pharmacopoeia, 30th ed, p871)
A form of intestinal obstruction caused by the PROLAPSE of a part of the intestine into the adjoining intestinal lumen. There are four types: colic, involving segments of the LARGE INTESTINE; enteric, involving only the SMALL INTESTINE; ileocecal, in which the ILEOCECAL VALVE prolapses into the CECUM, drawing the ILEUM along with it; and ileocolic, in which the ileum prolapses through the ileocecal valve into the COLON.
A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.
Constructions built to access underground water.
Pathological developments in the CECUM.
Inhaling liquid or solids, such as stomach contents, into the RESPIRATORY TRACT. When this causes severe lung damage, it is called ASPIRATION PNEUMONIA.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
Pathological conditions in the DUODENUM region of the small intestine (INTESTINE, SMALL).
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
A segment of the COLON between the RECTUM and the descending colon.
A pathological condition characterized by the presence of a number of COLONIC DIVERTICULA in the COLON. Its pathogenesis is multifactorial, including colon aging, motor dysfunction, increases in intraluminal pressure, and lack of dietary fibers.
The distal segment of the LARGE INTESTINE, between the SIGMOID COLON and the ANAL CANAL.
Production of a radiographic image of a small or very thin object on fine-grained photographic film under conditions which permit subsequent microscopic examination or enlargement of the radiograph at linear magnifications of up to several hundred and with a resolution approaching the resolving power of the photographic emulsion (about 1000 lines per millimeter).
Dilatation of the COLON, often to alarming dimensions. There are various types of megacolon including congenital megacolon in HIRSCHSPRUNG DISEASE, idiopathic megacolon in CONSTIPATION, and TOXIC MEGACOLON.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
Zeolites. A group of crystalline, hydrated alkali-aluminum silicates. They occur naturally in sedimentary and volcanic rocks, altered basalts, ores, and clay deposits. Some 40 known zeolite minerals and a great number of synthetic zeolites are available commercially. (From Merck Index, 11th ed)
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
Pathological development in the ILEUM including the ILEOCECAL VALVE.
Substances that are energetically unstable and can produce a sudden expansion of the material, called an explosion, which is accompanied by heat, pressure and noise. Other things which have been described as explosive that are not included here are explosive action of laser heating, human performance, sudden epidemiological outbreaks, or fast cell growth.
Passage of food (sometimes in the form of a test meal) through the gastrointestinal tract as measured in minutes or hours. The rate of passage through the intestine is an indicator of small bowel function.
The fusion of ceramics (porcelain) to an alloy of two or more metals for use in restorative and prosthodontic dentistry. Examples of metal alloys employed include cobalt-chromium, gold-palladium, gold-platinum-palladium, and nickel-based alloys.
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.
Coronary vasodilator that is an analog of iproveratril (VERAPAMIL) with one more methoxy group on the benzene ring.
The black, tarry, foul-smelling FECES that contain degraded blood.
The physiologic or functional barrier to GASTROESOPHAGEAL REFLUX at the esophagogastric junction. Sphincteric muscles remain tonically contracted during the resting state and form the high-pressure zone separating the lumen of the ESOPHAGUS from that of the STOMACH. (Haubrich et al, Bockus Gastroenterology, 5th ed., pp399, 415)
A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)
Discrete tissue masses that protrude into the lumen of the COLON. These POLYPS are connected to the wall of the colon either by a stalk, pedunculus, or by a broad base.
Radiographic visualization of the body between the thorax and the pelvis, i.e., within the peritoneal cavity.
Examination of any part of the body for diagnostic purposes by means of X-RAYS or GAMMA RAYS, recording the image on a sensitized surface (such as photographic film).
Discrete abnormal tissue masses that protrude into the lumen of the INTESTINE. A polyp is attached to the intestinal wall either by a stalk, pedunculus, or by a broad base.
Twisting of the STOMACH that may result in gastric ISCHEMIA and GASTRIC OUTLET OBSTRUCTION. It is often associated with DIAPHRAGMATIC HERNIA.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
A pouch or sac developed from a tubular or saccular organ, such as the GASTROINTESTINAL TRACT.
The ability of a substrate to allow the passage of ELECTRONS.
Tetraethylammonium compounds refer to a group of organic salts containing the tetraethylammonium ion (N(C2H5)4+), which is characterized by four ethyl groups bonded to a central nitrogen atom, and are commonly used in research and medicine as pharmacological tools for studying ion channels.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Inflammation of the COLONIC DIVERTICULA, generally with abscess formation and subsequent perforation.
Agents that are used to stimulate evacuation of the bowels.
An abnormal anatomical passage between the INTESTINE, and another segment of the intestine or other organs. External intestinal fistula is connected to the SKIN (enterocutaneous fistula). Internal intestinal fistula can be connected to a number of organs, such as STOMACH (gastrocolic fistula), the BILIARY TRACT (cholecystoduodenal fistula), or the URINARY BLADDER of the URINARY TRACT (colovesical fistula). Risk factors include inflammatory processes, cancer, radiation treatment, and surgical misadventures (MEDICAL ERRORS).
Hindrance of the passage of luminal contents in the DUODENUM. Duodenal obstruction can be partial or complete, and caused by intrinsic or extrinsic factors. Simple obstruction is associated with diminished or stopped flow of luminal contents. Strangulating obstruction is associated with impaired blood flow to the duodenum in addition to obstructed flow of luminal contents.
A type of lung inflammation resulting from the aspiration of food, liquid, or gastric contents into the upper RESPIRATORY TRACT.
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.
Endoscopic examination, therapy or surgery of the esophagus.
The valve, at the junction of the CECUM with the COLON, that guards the opening where the ILEUM enters the LARGE INTESTINE.
The quality or state of being able to be bent or creased repeatedly. (From Webster, 3d ed)
Mobilization of the lower end of the esophagus and plication of the fundus of the stomach around it (fundic wrapping) in the treatment of GASTROESOPHAGEAL REFLUX that may be associated with various disorders, such as hiatal hernia. (From Dorland, 28th ed)
An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.
Procedures of applying ENDOSCOPES for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. transluminal, to examine or perform surgery on the interior parts of the body.

Nonbehavioral selection for pawns, mutants of Paramecium aurelia with decreased excitability. (1/1812)

The reversal response in Paramecium aurelia is mediated by calcium which carries the inward current during excitation. Electrophysiological studies indicate that strontium and barium can also carry the inward current. Exposure to high concentrations of barium rapidly paralyzes and later kills wild-type paramecia. Following mutagenesis with nitrosoguanidine, seven mutants which continued to swim in the ;high-barium' solution were selected. All of the mutants show decreased reversal behavior, with phenotypes ranging from extremely non-reversing (;extreme' pawns) to nearly wild-type reversal behavior (;partial' pawns). The mutations fall into three complementation groups, identical to the pwA, pwB, and pwC genes of Kunget al. (1975). All of the pwA and pwB mutants withstand longer exposure to barium, the pwB mutants surviving longer than the pwA mutants. Among mutants of each gene, survival is correlated with loss of reversal behavior. Double mutants (A-B, A-C, B-C), identified in the exautogamous progeny of crosses between ;partial' mutants, exhibited a more extreme non-reversing phenotype than either of their single-mutant (;partial' pawn) parents.---Inability to reverse could be expected from an alteration in the calcium-activated reversal mechanism or in excitation. A normal calcium-activated structure was demonstrated in all pawns by chlorpromazine treatment. In a separate report (Schein, Bennett and Katz 1976) the results of electrophysiological investigations directly demonstrate decreased excitability in all of the mutants, a decrease due to an altered calcium activation. The studies of the genetics, the survival in barium and the electro-physiology of the pawns demonstrate that the pwA and pwB genes have different effects on calcium activation.  (+info)

Inducible genetic suppression of neuronal excitability. (2/1812)

Graded, reversible suppression of neuronal excitability represents a logical goal of therapy for epilepsy and intractable pain. To achieve such suppression, we have developed the means to transfer "electrical silencing" genes into neurons with sensitive control of transgene expression. An ecdysone-inducible promoter drives the expression of inwardly rectifying potassium channels in polycistronic adenoviral vectors. Infection of superior cervical ganglion neurons did not affect normal electrical activity but suppressed excitability after the induction of gene expression. These experiments demonstrate the feasibility of controlled ion channel expression after somatic gene transfer into neurons and serve as the prototype for a novel generalizable approach to modulate excitability.  (+info)

Activation of human D3 dopamine receptor inhibits P/Q-type calcium channels and secretory activity in AtT-20 cells. (3/1812)

The D3 dopamine receptor is postulated to play an important role in the regulation of neurotransmitter secretion at both pre- and postsynaptic terminals. However, this hypothesis and the underlying mechanisms remain untested because of the lack of D3-selective ligands, paucity of appropriate model secretory systems, and the weak and inconsistent coupling of D3 receptors to classical signal transduction pathways. The absence of ligands that selectively discriminate between D3 and D2 receptors in vivo precludes the study of D3 receptor function in the brain and necessitates the use of heterologous expression systems. In this report we demonstrate that activation of the human D3 dopamine receptor expressed in the AtT-20 neuroendocrine cell line causes robust inhibition of P/Q-type calcium channels via pertussis toxin-sensitive G-proteins. In addition, using the vesicle trafficking dye FM1-43, we show that D3 receptor activation significantly inhibits spontaneous secretory activity in these cells. Our results not only support the hypothesis that the D3 receptor can regulate secretory activity but also provide insight into the underlying signaling mechanisms. We propose a functional model in which the D3 receptor tightly regulates neurotransmitter release at a synapse by only allowing the propagation of spikes above a certain frequency or burst-duration threshold.  (+info)

Volume regulation following hypotonic shock in isolated crypts of mouse distal colon. (4/1812)

1. A video-imaging technique of morphometry was used to measure the diameter as an index of cell volume in intact mouse distal colon crypts submitted to hypotonic shock. 2. Transition from isotonic (310 mosmol l-1) to hypotonic (240 mosmol l-1) saline caused a pronounced increase in crypt diameter immediately followed by regulatory volume decrease (RVD). 3. Exposure of crypts to Cl--free hyposmotic medium increased the rapidity of both cell swelling and RVD. Exposure of crypts to Na+-free hyposmotic medium reduced the total duration of swelling. Return to initial diameter was followed by further shrinkage of the crypt cells. 4. The chloride channel inhibitor NPPB (50 microM) delayed the swelling phase and prevented the subsequent normal decrease in diameter. 5. The K+ channel blockers barium (10 mM), charybdotoxin (10 nM) and TEA (5 mM) inhibited RVD by 51, 44 and 32 %, respectively. 6. Intracellular [Ca2+] rose from a baseline of 174 +/- 17 nM (n = 8) to 448 +/- 45 nM (n = 8) during the initial swelling phase 7. The Ca2+ channel blockers verapamil (50 microM) and nifedipine (10 microM), the chelator of intracellular Ca2+ BAPTA AM (30 microM), or the inhibitor of Ca2+ release TMB-8 (10 microM), dramatically reduced volume recovery, leading to 51 % (n = 9), 25 % (n = 7), 37 % (n = 6), 32 % (n = 8) inhibition of RVD, respectively. TFP (50 microM), an antagonist of the Ca2+-calmodulin complex, significantly slowed RVD. The Ca2+ ionophore A23187 (2 microM) provoked a dramatic reduction of the duration and amplitude of cell swelling followed by extensive shrinkage. The release of Ca2+ from intracellular stores using bradykinin (1 microM) or blockade of reabsorption with thapsigargin (1 microM) decreased the duration of RVD. 8. Prostaglandin E2 (PGE2, 5 microM) slightly delayed RVD, whereas leukotriene D4 (LTD4, 100 nM) and arachidonic acid (10 microM) reduced the duration of RVD. Blockade of phospholipase A2 by quinacrine (10 microM) inhibited RVD by 53 %. Common inhibition of PGE2 and LTD4 synthesis by ETYA (50 microM) or separate blockade of PGE2 synthesis by 1 microM indomethacin reduced the duration of RVD. Blockade of LTD4 synthesis by nordihydroguaiaretic acid (NDGA) did not produce any significant effect on cell swelling or subsequent RVD. 9. Staurosporine (1 microM), an inhibitor of protein kinases, inhibited RVD by 58 %. Taken together the experiments demonstrate that the RVD process is under the control of conductive pathways, extra- and intracellular Ca2+ ions, protein kinases, prostaglandins and leukotrienes.  (+info)

Modulation of chloride, potassium and bicarbonate transport by muscarinic receptors in a human adenocarcinoma cell line. (5/1812)

1. Short-circuit current (I(SC)) responses to carbachol (CCh) were investigated in Colony 1 epithelia, a subpopulation of the HCA-7 adenocarcinoma cell line. In Krebs-Henseleit (KH) buffer, CCh responses consisted of three I(SC) components: an unusual rapid decrease (the 10 s spike) followed by an upward spike at 30 s and a slower transient increase (the 2 min peak). This response was not potentiated by forskolin; rather, CCh inhibited cyclic AMP-stimulated I(SC). 2. In HCO3- free buffer, the decrease in forskolin-elevated I(SC) after CCh was reduced, although the interactions between CCh and forskolin remained at best additive rather than synergistic. When Cl- anions were replaced by gluconate, both Ca2+- and cyclic AMP-mediated electrogenic responses were significantly inhibited. 3. Basolateral Ba2+ (1-10 mM) and 293B (10 microM) selectively inhibited forskolin stimulation of I(SC), without altering the effects of CCh. Under Ba2+- or 293B-treated conditions, CCh responses were potentiated by pretreatment with forskolin. 4. Basolateral charybdotoxin (50 nM) significantly increased the size of the 10 s spike of CCh responses in both KH and HCO3- free medium, without affecting the 2 min peak. The enhanced 10 s spike was inhibited by prior addition of 5 mM apical Ba2+. Charybdotoxin did not affect forskolin responses. 5. In epithelial layers prestimulated with forskolin, the muscarinic antagonists atropine and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, both at 100 nM) abolished subsequent 10 microM CCh responses. Following addition of p-fluoro hexahydro-sila-difenidol (pF-HHSiD, 10 microM) or pirenzepine (1 microM), qualitative changes in the CCh response time-profile also indicated a rightward shift of the agonist concentration-response curve; however, 1 microM gallamine had no effect. These results suggest that a single M3-like receptor subtype mediates the secretory response to CCh. 6. It is concluded that CCh and forskolin activate discrete populations of basolateral K+ channels gated by either Ca2+ or cyclic AMP, but that the Cl- permeability of the apical membrane may limit their combined effects on electrogenic Cl- secretion. In addition, CCh activates a Ba2+-sensitive apical K+ conductance leading to electrogenic K+ transport. Both agents may also modulate HCO3- secretion through a mechanism at least partially dependent on carbonic anhydrase.  (+info)

Selective activation of heterologously expressed G protein-gated K+ channels by M2 muscarinic receptors in rat sympathetic neurones. (6/1812)

1. G protein-regulated inward rectifier K+ (GIRK) channels were over-expressed in dissociated rat superior cervical sympathetic (SCG) neurones by co-transfecting green fluorescent protein (GFP)-, GIRK1- and GIRK2-expressing plasmids using the biolistic technique. Membrane currents were subsequently recorded with whole-cell patch electrodes. 2. Co-transfected cells had larger Ba2+-sensitive inwardly rectifying currents and 13 mV more negative resting potentials (in 3 mM [K+]o) than non-transfected cells, or cells transfected with GIRK1 or GIRK2 alone. 3. Carbachol (CCh, 1-30 microM) increased the inwardly rectifying current in 70 % of GIRK1+ GIRK2-transfected cells by 261 +/- 53 % (n = 6, CCh 30 microM) at -120 mV, but had no effect in non-transfected cells or in cells transfected with GIRK1 or GIRK2 alone. Pertussis toxin prevented the effect of carbachol but had no effect on basal currents. 4. The effect of CCh was antagonized by 6 nM tripitramine but not by 100 nM pirenzepine, consistent with activation of endogenous M2 muscarinic acetylcholine receptors. 5. In contrast, inhibition of the voltage-activated Ca2+ current by CCh was antagonized by 100 nM pirenzepine but not by 6 nM tripitramine, indicating that it was mediated by M4 muscarinic acetylcholine receptors. 6. We conclude that endogenous M2 and M4 muscarinic receptors selectively couple to GIRK currents and Ca2+ currents respectively, with negligible cross-talk.  (+info)

Kir2.1 encodes the inward rectifier potassium channel in rat arterial smooth muscle cells. (7/1812)

1. The molecular nature of the strong inward rectifier K+ channel in vascular smooth muscle was explored by using isolated cell RT-PCR, cDNA cloning and expression techniques. 2. RT-PCR of RNA from single smooth muscle cells of rat cerebral (basilar), coronary and mesenteric arteries revealed transcripts for Kir2.1. Transcripts for Kir2.2 and Kir2.3 were not found. 3. Quantitative PCR analysis revealed significant differences in transcript levels of Kir2.1 between the different vascular preparations (n = 3; P < 0.05). A two-fold difference was detected between Kir2.1 mRNA and beta-actin mRNA in coronary arteries when compared with relative levels measured in mesenteric and basilar preparations. 4. Kir2.1 was cloned from rat mesenteric vascular smooth muscle cells and expressed in Xenopus oocytes. Currents were strongly inwardly rectifying and selective for K+. 5. The effect of extracellular Ba2+, Ca2+, Mg2+ and Cs2+ ions on cloned Kir2.1 channels expressed in Xenopus oocytes was examined. Ba2+ and Cs+ block were steeply voltage dependent, whereas block by external Ca2+ and Mg2+ exhibited little voltage dependence. The apparent half-block constants and voltage dependences for Ba2+, Cs+, Ca2+ and Mg2+ were very similar for inward rectifier K+ currents from native cells and cloned Kir2.1 channels expressed in oocytes. 6. Molecular studies demonstrate that Kir2.1 is the only member of the Kir2 channel subfamily present in vascular arterial smooth muscle cells. Expression of cloned Kir2.1 in Xenopus oocytes resulted in inward rectifier K+ currents that strongly resemble those that are observed in native vascular arterial smooth muscle cells. We conclude that Kir2.1 encodes for inward rectifier K+ channels in arterial smooth muscle.  (+info)

Cross-coupling between voltage-dependent Ca2+ channels and ryanodine receptors in developing ascidian muscle blastomeres. (8/1812)

1. Ascidian blastomeres of muscle lineage express voltage-dependent calcium channels (VDCCs) despite isolation and cleavage arrest. Taking advantage of these large developing cells, developmental changes in functional relations between VDCC currents and intracellular Ca2+ stores were studied. 2. Inactivation of ascidian VDCCs is Ca2+ dependent, as demonstrated by two pieces of evidence: (1) a bell-shaped relationship between prepulse voltage and amplitude during the test pulse in Ca2+, but not in Ba2+, and (2) the decay kinetics of Ca2+ currents (ICa) obtained as the size of tail currents. 3. During replacement in the external solution of Ca2+ with Ba2+, the inward current appeared biphasic: it showed rapid decay followed by recovery and slow decay. This current profile was most evident in the mixed bath solution (2 % Ca2+ and 98 % Ba2+, abbreviated to '2Ca/98Ba'). 4. The biphasic profile of I2Ca/98Ba was significantly attenuated in caffeine and in ryanodine, indicating that Ca2+ release is involved in shaping the current kinetics of VDCCs. After washing out the caffeine, the biphasic pattern was reproducibly restored by depolarizing the membrane in calcium-rich solution, which is expected to refill the internal Ca2+ stores. 5. The inhibitors of endoplasmic reticulum (ER) Ca2+-ATPase (SERCAs) cyclopiazonic acid (CPA) and thapsigargin facilitated elimination of the biphasic profile with repetitive depolarization. 6. At a stage earlier than 36 h after fertilization, the biphasic profile of I2Ca/98Ba was not observed. However, caffeine induced a remarkable decrease in the amplitude of I2Ca/98Ba and this suppression was blocked by microinjection of the Ca2+ chelator BAPTA, showing the presence of caffeine-sensitive Ca2+ stores at this stage. 7. Electron microscopic observation shows that sarcoplasmic membranes (SR) arrange closer to the sarcolemma with maturation, suggesting that the formation of the ultrastructural machinery underlies development of the cross-coupling between VDCCs and Ca2+ stores.  (+info)

Barium sulfate is a medication that is commonly used as a contrast material in medical imaging procedures, such as X-rays and CT scans. It works by coating the inside of the digestive tract, making it visible on an X-ray or CT scan and allowing doctors to see detailed images of the stomach, intestines, and other parts of the digestive system.

Barium sulfate is a white, chalky powder that is mixed with water to create a thick, milky liquid. It is generally safe and does not cause significant side effects when used in medical imaging procedures. However, it should not be taken by individuals who have a known allergy to barium or who have certain digestive conditions, such as obstructions or perforations of the bowel.

It's important to note that while barium sulfate is an important tool for medical diagnosis, it is not a treatment for any medical condition and should only be used under the direction of a healthcare professional.

Barium is a naturally occurring, silvery-white metallic chemical element with the symbol Ba and atomic number 56. In medical terms, barium is commonly used as a contrast agent in radiology, particularly in X-ray examinations such as an upper GI series or barium enema. The barium sulfate powder is mixed with water to create a liquid or thick paste that is swallowed or inserted through the rectum. This provides a white coating on the inside lining of the digestive tract, allowing it to be seen more clearly on X-ray images and helping doctors diagnose various conditions such as ulcers, tumors, or inflammation.

It's important to note that barium is not absorbed by the body and does not cause any harm when used in medical imaging procedures. However, if it is accidentally inhaled or aspirated into the lungs during administration, it can cause chemical pneumonitis, a potentially serious condition. Therefore, it should only be administered under the supervision of trained medical professionals.

Barium compounds are inorganic substances that contain the metallic element barium (Ba) combined with one or more other elements. Barium is an alkaline earth metal that is highly reactive and toxic in its pure form. However, when bound with other elements to form barium compounds, it can be used safely for various medical and industrial purposes.

In medicine, barium compounds are commonly used as a contrast material for X-ray examinations of the digestive system. When a patient swallows a preparation containing barium sulfate, the dense compound coats the lining of the esophagus, stomach, and intestines, making them visible on an X-ray image. This allows doctors to diagnose conditions such as ulcers, tumors, or blockages in the digestive tract.

Other barium compounds include barium carbonate, barium chloride, and barium hydroxide, which are used in various industrial applications such as drilling muds, flame retardants, and pigments for paints and plastics. However, these compounds can be toxic if ingested or inhaled, so they must be handled with care.

An enema is a medical procedure in which liquid is introduced into the lower part of the large intestine, specifically the sigmoid colon or rectum, through the anus using a special device called an enema kit. The liquid used can be plain water, saline solution, or a medicated solution, and it is typically retained for a short period of time before being expelled.

The purpose of an enema may vary, but it is often used to relieve constipation, prepare the bowel for medical procedures such as colonoscopy, or administer medications or nutrients that cannot be taken by mouth. Enemas can also be used for therapeutic purposes, such as to stimulate the immune system or promote relaxation.

It is important to follow proper instructions when administering an enema to avoid injury or discomfort. Possible side effects of enemas may include cramping, bloating, nausea, or electrolyte imbalances. If you have any health concerns or conditions that may be affected by an enema, it is recommended to consult with a healthcare professional before using one.

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.

A diverticulum of the colon is a small sac or pouch that forms in the wall of the large intestine (colon). These sacs usually develop in areas where the blood vessels pass through the muscle layer of the colon, creating a weak spot that eventually bulges outward. Diverticula can occur anywhere along the length of the colon, but they are most commonly found in the lower part of the colon, also known as the sigmoid colon.

Diverticula themselves are not harmful and often do not cause any symptoms. However, when these sacs become inflamed or infected, it can lead to a condition called diverticulitis, which can cause pain, fever, nausea, vomiting, constipation, or diarrhea. Diverticulitis is usually treated with antibiotics and a liquid diet, but in severe cases, surgery may be required.

Risk factors for developing colonic diverticula include aging, obesity, smoking, low fiber intake, and lack of physical activity. Regular screening is recommended for individuals over the age of 50 to detect and prevent complications associated with diverticular disease.

Sigmoidoscopy is a medical procedure that involves the insertion of a sigmoidoscope, a flexible tube with a light and camera at the end, into the rectum and lower colon (sigmoid colon) to examine these areas for any abnormalities such as inflammation, ulcers, polyps, or cancer. The procedure typically allows for the detection of issues in the sigmoid colon and rectum, and can help diagnose conditions such as inflammatory bowel disease, diverticulosis, or colorectal cancer.

There are two types of sigmoidoscopy: flexible sigmoidoscopy and rigid sigmoidoscopy. Flexible sigmoidoscopy is more commonly performed because it provides a better view of the lower colon and is less uncomfortable for the patient. Rigid sigmoidoscopy, on the other hand, uses a solid, inflexible tube and is typically used in specific situations such as the removal of foreign objects or certain types of polyps.

During the procedure, patients are usually positioned on their left side with their knees drawn up to their chest. The sigmoidoscope is gently inserted into the rectum and advanced through the lower colon while the doctor examines the lining for any abnormalities. Air may be introduced through the scope to help expand the colon and provide a better view. If polyps or other abnormal tissues are found, they can often be removed during the procedure for further examination and testing.

Sigmoidoscopy is generally considered a safe and well-tolerated procedure. Some patients may experience mild discomfort, bloating, or cramping during or after the exam, but these symptoms typically resolve on their own within a few hours.

"Macrocystis" is a genus of large brown algae (Phaeophyceae) commonly known as giant kelp. It is one of the most widely distributed kelps, found in cold water environments throughout the world. Macrocystis species form dense underwater forests that provide important habitats for many marine organisms. The term "macrocystis" itself does not have a specific medical definition, but individual components of these algae have been used in traditional medicine and may be studied for potential medicinal properties.

Colonic diseases refer to a group of medical conditions that affect the colon, also known as the large intestine or large bowel. The colon is the final segment of the digestive system, responsible for absorbing water and electrolytes, and storing and eliminating waste products.

Some common colonic diseases include:

1. Inflammatory bowel disease (IBD): This includes conditions such as Crohn's disease and ulcerative colitis, which cause inflammation and irritation in the lining of the digestive tract.
2. Diverticular disease: This occurs when small pouches called diverticula form in the walls of the colon, leading to symptoms such as abdominal pain, bloating, and changes in bowel movements.
3. Colorectal cancer: This is a type of cancer that develops in the colon or rectum, often starting as benign polyps that grow and become malignant over time.
4. Irritable bowel syndrome (IBS): This is a functional gastrointestinal disorder characterized by abdominal pain, bloating, and changes in bowel movements, but without any underlying structural or inflammatory causes.
5. Constipation: This is a common condition characterized by infrequent bowel movements, difficulty passing stools, or both.
6. Infectious colitis: This occurs when the colon becomes infected with bacteria, viruses, or parasites, leading to symptoms such as diarrhea, abdominal cramps, and fever.

Treatment for colonic diseases varies depending on the specific condition and its severity. Treatment options may include medications, lifestyle changes, surgery, or a combination of these approaches.

A colonoscopy is a medical procedure used to examine the large intestine, also known as the colon and rectum. It is performed using a flexible tube with a tiny camera on the end, called a colonoscope, which is inserted into the rectum and gently guided through the entire length of the colon.

The procedure allows doctors to visually inspect the lining of the colon for any abnormalities such as polyps, ulcers, inflammation, or cancer. If any polyps are found during the procedure, they can be removed immediately using special tools passed through the colonoscope. Colonoscopy is an important tool in the prevention and early detection of colorectal cancer, which is one of the leading causes of cancer-related deaths worldwide.

Patients are usually given a sedative to help them relax during the procedure, which is typically performed on an outpatient basis in a hospital or clinic setting. The entire procedure usually takes about 30-60 minutes to complete, although patients should plan to spend several hours at the medical facility for preparation and recovery.

Deglutition disorders, also known as swallowing disorders, are conditions that affect the ability to move food or liquids from the mouth to the stomach safely and efficiently. These disorders can occur at any stage of the swallowing process, which includes oral preparation (chewing and manipulating food in the mouth), pharyngeal phase (activating muscles and structures in the throat to move food toward the esophagus), and esophageal phase (relaxing and contracting the esophagus to propel food into the stomach).

Symptoms of deglutition disorders may include coughing or choking during or after eating, difficulty initiating a swallow, food sticking in the throat or chest, regurgitation, unexplained weight loss, and aspiration (inhaling food or liquids into the lungs), which can lead to pneumonia.

Deglutition disorders can be caused by various factors, such as neurological conditions (e.g., stroke, Parkinson's disease, multiple sclerosis), structural abnormalities (e.g., narrowing or blockage of the esophagus), muscle weakness or dysfunction, and cognitive or behavioral issues. Treatment for deglutition disorders may involve dietary modifications, swallowing exercises, medications, or surgical interventions, depending on the underlying cause and severity of the condition.

Contrast media are substances that are administered to a patient in order to improve the visibility of internal body structures or processes in medical imaging techniques such as X-rays, CT scans, MRI scans, and ultrasounds. These media can be introduced into the body through various routes, including oral, rectal, or intravenous administration.

Contrast media work by altering the appearance of bodily structures in imaging studies. For example, when a patient undergoes an X-ray examination, contrast media can be used to highlight specific organs, tissues, or blood vessels, making them more visible on the resulting images. In CT and MRI scans, contrast media can help to enhance the differences between normal and abnormal tissues, allowing for more accurate diagnosis and treatment planning.

There are several types of contrast media available, each with its own specific properties and uses. Some common examples include barium sulfate, which is used as a contrast medium in X-ray studies of the gastrointestinal tract, and iodinated contrast media, which are commonly used in CT scans to highlight blood vessels and other structures.

While contrast media are generally considered safe, they can sometimes cause adverse reactions, ranging from mild symptoms such as nausea or hives to more serious complications such as anaphylaxis or kidney damage. As a result, it is important for healthcare providers to carefully evaluate each patient's medical history and individual risk factors before administering contrast media.

Esophageal achalasia is a rare disorder of the esophagus, the tube that carries food from the mouth to the stomach. In this condition, the muscles at the lower end of the esophagus fail to relax properly during swallowing, making it difficult for food and liquids to pass into the stomach. This results in symptoms such as difficulty swallowing (dysphagia), regurgitation of food, chest pain, and weight loss. The cause of esophageal achalasia is not fully understood, but it is believed to be related to damage to the nerves that control the muscles of the esophagus. Treatment options include medications to relax the lower esophageal sphincter, botulinum toxin injections, and surgical procedures such as laparoscopic Heller myotomy or peroral endoscopic myotomy (POEM).

Barium radioisotopes are radioactive forms of the element barium, which are used in medical imaging procedures to help diagnose various conditions. The radioisotopes emit gamma rays that can be detected by external devices, allowing doctors to visualize the inside of the body. Barium sulfate is often used as a contrast agent in X-rays and CT scans, but when combined with a radioisotope such as barium-133, barium-198, or barium-207, it can provide more detailed images of specific organs or systems.

For example, barium sulfate mixed with barium-133 may be used in a lung scan to help diagnose pulmonary embolism or other respiratory conditions. Barium-207 is sometimes used in bone scans to detect fractures, tumors, or infections.

It's important to note that the use of radioisotopes carries some risks, including exposure to radiation and potential allergic reactions to the barium compound. However, these risks are generally considered low compared to the benefits of accurate diagnosis and effective treatment.

Potassium is a essential mineral and an important electrolyte that is widely distributed in the human body. The majority of potassium in the body (approximately 98%) is found within cells, with the remaining 2% present in blood serum and other bodily fluids. Potassium plays a crucial role in various physiological processes, including:

1. Regulation of fluid balance and maintenance of normal blood pressure through its effects on vascular tone and sodium excretion.
2. Facilitation of nerve impulse transmission and muscle contraction by participating in the generation and propagation of action potentials.
3. Protein synthesis, enzyme activation, and glycogen metabolism.
4. Regulation of acid-base balance through its role in buffering systems.

The normal serum potassium concentration ranges from 3.5 to 5.0 mEq/L (milliequivalents per liter) or mmol/L (millimoles per liter). Potassium levels outside this range can have significant clinical consequences, with both hypokalemia (low potassium levels) and hyperkalemia (high potassium levels) potentially leading to serious complications such as cardiac arrhythmias, muscle weakness, and respiratory failure.

Potassium is primarily obtained through the diet, with rich sources including fruits (e.g., bananas, oranges, and apricots), vegetables (e.g., leafy greens, potatoes, and tomatoes), legumes, nuts, dairy products, and meat. In cases of deficiency or increased needs, potassium supplements may be recommended under the guidance of a healthcare professional.

Fluoroscopy is a type of medical imaging that uses X-rays to obtain real-time moving images of the internal structures of the body. A continuous X-ray beam is passed through the body part being examined, and the resulting fluoroscopic images are transmitted to a monitor, allowing the medical professional to view the structure and movement of the internal organs and bones in real time.

Fluoroscopy is often used to guide minimally invasive procedures such as catheterization, stent placement, or joint injections. It can also be used to diagnose and monitor a variety of medical conditions, including gastrointestinal disorders, musculoskeletal injuries, and cardiovascular diseases.

It is important to note that fluoroscopy involves exposure to ionizing radiation, and the risks associated with this exposure should be carefully weighed against the benefits of the procedure. Medical professionals are trained to use the lowest possible dose of radiation necessary to obtain the desired diagnostic information.

A hiatal hernia is a type of hernia that occurs when a part of the stomach protrudes or squeezes through an opening (hiatus) in the diaphragm, the muscular partition between the chest and abdominal cavities. Normally, the esophagus passes through this opening to connect to the stomach, but in a hiatal hernia, a portion of the stomach also moves up into the chest cavity through the hiatus.

There are two main types of hiatal hernias: sliding and paraesophageal. In a sliding hiatal hernia, the junction between the esophagus and stomach (gastroesophageal junction) slides upward into the chest cavity, which is the most common type. Paraesophageal hiatal hernias are less common but can be more severe, as they involve the stomach herniating alongside the esophagus, potentially leading to complications like obstruction or strangulation of the blood supply to the stomach.

Many people with hiatal hernias do not experience symptoms, but some may have heartburn, acid reflux, regurgitation, difficulty swallowing, chest pain, or shortness of breath. Treatment depends on the severity and associated symptoms, ranging from lifestyle modifications and medications to surgical repair in severe cases.

Deglutition is the medical term for swallowing. It refers to the process by which food or liquid is transferred from the mouth to the stomach through a series of coordinated muscle movements and neural responses. The deglutition process involves several stages, including oral preparatory, oral transit, pharyngeal, and esophageal phases, each of which plays a critical role in ensuring safe and efficient swallowing.

Dysphagia is the medical term for difficulty with swallowing, which can result from various underlying conditions such as neurological disorders, structural abnormalities, or muscular weakness. Proper evaluation and management of deglutition disorders are essential to prevent complications such as aspiration pneumonia, malnutrition, and dehydration.

"Laminaria" is a genus of brown algae that grows in cooler waters and is often used in medical procedures as a preparation for dilating the cervix. The dried and sterilized form of Laminaria japonica, a species of this seaweed, is known as "Laminaria tents" or "Laminaria sticks." These are gradually inserted into the cervix where they absorb water and expand over a period of hours, dilating the cervix. This is most commonly done in preparation for a surgical procedure such as a dilation and curettage (D&C) or an abortion. It's important to note that this process should be performed by a healthcare professional in a clinical setting.

Manometry is a medical test that measures pressure inside various parts of the gastrointestinal tract. It is often used to help diagnose digestive disorders such as achalasia, gastroparesis, and irritable bowel syndrome. During the test, a thin, flexible tube called a manometer is inserted through the mouth or rectum and into the area being tested. The tube is connected to a machine that measures and records pressure readings. These readings can help doctors identify any abnormalities in muscle function or nerve reflexes within the digestive tract.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

The esophagus is the muscular tube that connects the throat (pharynx) to the stomach. It is located in the midline of the neck and chest, passing through the diaphragm to enter the abdomen and join the stomach. The main function of the esophagus is to transport food and liquids from the mouth to the stomach for digestion.

The esophagus has a few distinct parts: the upper esophageal sphincter (a ring of muscle that separates the esophagus from the throat), the middle esophagus, and the lower esophageal sphincter (another ring of muscle that separates the esophagus from the stomach). The lower esophageal sphincter relaxes to allow food and liquids to enter the stomach and then contracts to prevent stomach contents from flowing back into the esophagus.

The walls of the esophagus are made up of several layers, including mucosa (a moist tissue that lines the inside of the tube), submucosa (a layer of connective tissue), muscle (both voluntary and involuntary types), and adventitia (an outer layer of connective tissue).

Common conditions affecting the esophagus include gastroesophageal reflux disease (GERD), Barrett's esophagus, esophageal cancer, esophageal strictures, and eosinophilic esophagitis.

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.

Cholecystography is a medical procedure that involves the use of X-rays to examine the gallbladder and bile ducts. It is also known as an oral cholecystogram (OCG).

The procedure involves administering a contrast agent, typically a iodine-based dye, which is absorbed by the liver and excreted into the bile ducts and gallbladder. The dye makes the bile ducts and gallbladder visible on X-ray images, allowing doctors to diagnose conditions such as gallstones, tumors, or inflammation of the gallbladder.

Cholecystography is not commonly used today due to the development of more advanced imaging techniques, such as ultrasound and computed tomography (CT) scans, which are non-invasive and do not require the use of contrast agents. However, it may still be used in certain cases where other imaging tests are inconclusive or unavailable.

Potassium channels are membrane proteins that play a crucial role in regulating the electrical excitability of cells, including cardiac, neuronal, and muscle cells. These channels facilitate the selective passage of potassium ions (K+) across the cell membrane, maintaining the resting membrane potential and shaping action potentials. They are composed of four or six subunits that assemble to form a central pore through which potassium ions move down their electrochemical gradient. Potassium channels can be modulated by various factors such as voltage, ligands, mechanical stimuli, or temperature, allowing cells to fine-tune their electrical properties and respond to different physiological demands. Dysfunction of potassium channels has been implicated in several diseases, including cardiac arrhythmias, epilepsy, and neurodegenerative disorders.

Computed tomographic colonography (CTC), also known as virtual colonoscopy, is a medical imaging technique that uses computed tomography (CT) scans to produce detailed images of the large intestine (colon) and rectum. In CTC, specialized software creates two- and three-dimensional images of the colon's inner surface, allowing healthcare providers to examine the colon for polyps, tumors, and other abnormalities.

During a CTC procedure, patients are usually given a mild laxative and asked to follow a clear liquid diet beforehand to clean out the colon. A small tube is inserted into the rectum to inflate the colon with air or carbon dioxide, making it easier to visualize any abnormalities. The patient lies on their back and then their stomach while the CT scanner takes multiple images of the abdomen and pelvis from different angles.

CTC has several advantages over traditional colonoscopy, including less invasiveness, lower risk of complications, faster recovery time, and the ability to examine the entire colon without missing any areas. However, if polyps or other abnormalities are detected during a CTC, a follow-up diagnostic colonoscopy may be necessary for removal or further evaluation.

It is important to note that CTC does not replace traditional colonoscopy as a screening tool for colorectal cancer. While it has similar accuracy in detecting large polyps and cancers, its ability to detect smaller polyps is less reliable compared to optical colonoscopy. Therefore, guidelines recommend using CTC as an alternative option for individuals who cannot or do not wish to undergo traditional colonoscopy, or as a supplemental screening tool for those at higher risk of colorectal cancer.

Esophageal diseases refer to a range of medical conditions that affect the esophagus, which is the muscular tube that connects the throat to the stomach. Here are some common esophageal diseases with their brief definitions:

1. Gastroesophageal reflux disease (GERD): A chronic condition in which stomach acid or bile flows back into the esophagus, causing symptoms such as heartburn, chest pain, and difficulty swallowing.
2. Esophagitis: Inflammation of the esophageal lining, often caused by GERD, infection, or medication.
3. Esophageal stricture: Narrowing of the esophagus due to scarring or inflammation, which can make swallowing difficult.
4. Esophageal cancer: Cancer that forms in the tissues of the esophagus, often as a result of long-term GERD or smoking.
5. Esophageal motility disorders: Disorders that affect the normal movement and function of the esophagus, such as achalasia, diffuse spasm, and nutcracker esophagus.
6. Barrett's esophagus: A condition in which the lining of the lower esophagus changes, increasing the risk of esophageal cancer.
7. Esophageal diverticula: Small pouches that form in the esophageal wall, often causing difficulty swallowing or regurgitation.
8. Eosinophilic esophagitis (EoE): A chronic immune-mediated disorder characterized by inflammation of the esophagus due to an allergic reaction.

These are some of the common esophageal diseases, and their diagnosis and treatment may vary depending on the severity and underlying cause of the condition.

Gastrointestinal (GI) hemorrhage is a term used to describe any bleeding that occurs in the gastrointestinal tract, which includes the esophagus, stomach, small intestine, large intestine, and rectum. The bleeding can range from mild to severe and can produce symptoms such as vomiting blood, passing black or tarry stools, or having low blood pressure.

GI hemorrhage can be classified as either upper or lower, depending on the location of the bleed. Upper GI hemorrhage refers to bleeding that occurs above the ligament of Treitz, which is a point in the small intestine where it becomes narrower and turns a corner. Common causes of upper GI hemorrhage include gastritis, ulcers, esophageal varices, and Mallory-Weiss tears.

Lower GI hemorrhage refers to bleeding that occurs below the ligament of Treitz. Common causes of lower GI hemorrhage include diverticulosis, colitis, inflammatory bowel disease, and vascular abnormalities such as angiodysplasia.

The diagnosis of GI hemorrhage is often made based on the patient's symptoms, medical history, physical examination, and diagnostic tests such as endoscopy, CT scan, or radionuclide scanning. Treatment depends on the severity and cause of the bleeding and may include medications, endoscopic procedures, surgery, or a combination of these approaches.

An esophageal diverticulum is a small pouch or sac that forms as a result of a protrusion or herniation of the inner lining (mucosa) of the esophagus through the outer layer of muscle in the wall of the esophagus. Esophageal diverticula can occur in any part of the esophagus, but they are most commonly found in the lower third of the esophagus, near the junction with the stomach.

Esophageal diverticula may be congenital (present at birth) or acquired (develop later in life). Acquired esophageal diverticula are often associated with underlying conditions such as esophageal motility disorders, strictures, or tumors that increase the pressure inside the esophagus and cause the mucosa to bulge out through weakened areas of the esophageal wall.

Symptoms of esophageal diverticula may include difficulty swallowing (dysphagia), regurgitation of undigested food, chest pain, heartburn, and recurrent respiratory infections due to aspiration of food or saliva into the lungs. Treatment options for esophageal diverticula depend on the size and location of the diverticulum, as well as the presence of any underlying conditions. Small asymptomatic diverticula may not require treatment, while larger symptomatic diverticula may be treated with surgical removal or endoscopic repair.

Electron Probe Microanalysis (EPMA) is a technique used in materials science and geology to analyze the chemical composition of materials at very small scales, typically on the order of microns or less. In this technique, a focused beam of electrons is directed at a sample, causing the emission of X-rays that are characteristic of the elements present in the sample. By analyzing the energy and intensity of these X-rays, researchers can determine the concentration of different elements in the sample with high precision and accuracy.

EPMA is typically performed using a specialized instrument called an electron probe microanalyzer (EPMA), which consists of an electron column for generating and focusing the electron beam, an X-ray spectrometer for analyzing the emitted X-rays, and a stage for positioning and manipulating the sample. The technique is widely used in fields such as mineralogy, geochemistry, metallurgy, and materials science to study the composition and structure of minerals, alloys, semiconductors, and other materials.

One of the key advantages of EPMA is its ability to analyze the chemical composition of small regions within a sample, even in cases where there are spatial variations in composition or where the sample is heterogeneous. This makes it an ideal technique for studying the distribution and behavior of trace elements in minerals, the microstructure of alloys and other materials, and the composition of individual grains or phases within a polyphase material. Additionally, EPMA can be used to analyze both conductive and non-conductive samples, making it a versatile tool for a wide range of applications.

Intestinal obstruction, also known as bowel obstruction, is a medical condition characterized by a blockage that prevents the normal flow of contents through the small intestine or large intestine (colon). This blockage can be caused by various factors such as tumors, adhesions (scar tissue), hernias, inflammation, or impacted feces.

The obstruction can be mechanical, where something physically blocks the intestinal lumen, or functional, where the normal muscular contractions of the bowel are impaired. Mechanical obstructions are more common than functional ones.

Symptoms of intestinal obstruction may include abdominal pain and cramping, nausea and vomiting, bloating, inability to pass gas or have a bowel movement, and abdominal distention. If left untreated, intestinal obstruction can lead to serious complications such as tissue death (necrosis), perforation of the intestine, and sepsis. Treatment typically involves hospitalization, intravenous fluids, nasogastric decompression, and possibly surgery to remove the obstruction.

Diatrizoate Meglumine is a type of contrast medium that is used during X-ray examinations, such as CT scans and angiography. It is a radiopaque substance, which means that it contains atoms that absorb X-rays, making it possible to visualize the internal structures of the body on an X-ray image.

Diatrizoate Meglumine is a salt of diatrizoic acid, which is a type of ionic contrast medium. It works by increasing the contrast between different tissues and organs in the body, making them easier to distinguish on an X-ray image. This can help doctors to diagnose a wide range of medical conditions, including injuries, tumors, and vascular diseases.

Like all medications, Diatrizoate Meglumine can have side effects, including allergic reactions, kidney damage, and thyroid problems. It is important for patients to discuss any potential risks and benefits with their doctor before undergoing an X-ray examination that involves the use of this contrast medium.

Occult blood refers to the presence of blood in the stool or gastrointestinal tract that is not visible to the naked eye. It is typically detected through chemical tests, such as fecal occult blood tests (FOBT) or fecal immunochemical tests (FIT), which can detect small amounts of blood in the stool. The presence of occult blood may indicate a variety of gastrointestinal conditions, including colorectal cancer, polyps, ulcers, inflammatory bowel disease, and other digestive disorders. It is important to follow up with medical evaluation if occult blood is detected, as early detection and treatment of underlying conditions can improve outcomes.

Bisacodyl is a stimulant laxative that is used to treat constipation and to clean out the intestines before a colonoscopy or other medical procedures. It works by increasing the muscle contractions in the intestines, which helps to move stool through the bowels and promotes bowel movements. Bisacodyl is available as a tablet or suppository, and it is typically taken at night to produce a bowel movement the next morning.

Bisacodyl is a prescription medication, and it should be used under the guidance of a healthcare professional. It is important to follow the instructions for use carefully, as improper use can increase the risk of side effects such as dehydration, electrolyte imbalances, and dependence on laxatives.

Some common side effects of bisacodyl include abdominal cramping, diarrhea, and nausea. These side effects are usually mild and go away on their own. However, if they are severe or persist, it is important to talk to a healthcare professional. In rare cases, bisacodyl can cause more serious side effects such as allergic reactions, heart problems, and intestinal inflammation. If you experience any of these side effects, seek medical attention immediately.

It is important to note that bisacodyl is not recommended for long-term use, as it can lead to dependence on laxatives and other health problems. It should only be used as directed by a healthcare professional and for the shortest duration necessary to treat constipation or prepare for a medical procedure.

Intussusception is a medical condition in which a part of the intestine telescopes into an adjacent section, leading to bowel obstruction and reduced blood flow. It often affects children under 3 years old but can also occur in adults. If not treated promptly, it can result in serious complications such as perforation, peritonitis, or even death. The exact cause is usually unknown, but it may be associated with infections, intestinal disorders, or tumors.

Cesium is a chemical element with the symbol "Cs" and atomic number 55. It is a soft, silvery-golden alkali metal that is highly reactive. Cesium is never found in its free state in nature due to its high reactivity. Instead, it is found in minerals such as pollucite.

In the medical field, cesium-137 is a radioactive isotope of cesium that has been used in certain medical treatments and diagnostic procedures. For example, it has been used in the treatment of cancer, particularly in cases where other forms of radiation therapy have not been effective. It can also be used as a source of radiation in brachytherapy, a type of cancer treatment that involves placing radioactive material directly into or near tumors.

However, exposure to high levels of cesium-137 can be harmful and may increase the risk of cancer and other health problems. Therefore, its use in medical treatments is closely regulated and monitored to ensure safety.

"Water wells" are not a medical term, but rather a term used in environmental and public health fields. A water well is a structure created to access groundwater in underground aquifers. They can be drilled or dug, and the water they provide is often used for drinking, irrigation, and other purposes.

In the context of medicine and public health, water wells are important because they can provide a safe source of clean water, which is essential for preventing waterborne diseases such as cholera, typhoid fever, and hepatitis A. However, if water wells are not constructed or maintained properly, they can become contaminated with bacteria, viruses, chemicals, or other pollutants that can cause illness. Therefore, it's important to regularly test and monitor the quality of water from wells to ensure it's safe for consumption.

Cecal diseases refer to medical conditions that affect the cecum, which is a pouch-like structure located at the junction of the small and large intestines. The cecum plays an important role in digestion, particularly in the fermentation of certain types of food.

There are several different types of cecal diseases, including:

1. Cecal volvulus: This is a rare condition in which the cecum twists on itself, cutting off blood flow and causing severe pain and other symptoms.
2. Diverticulitis: This occurs when small pouches called diverticula form in the wall of the cecum and become inflamed or infected.
3. Appendicitis: Although not strictly a cecal disease, the appendix is a small tube-like structure that branches off from the cecum. Inflammation of the appendix (appendicitis) can cause severe pain in the lower right abdomen and may require surgical removal of the appendix.
4. Crohn's disease: This is a chronic inflammatory bowel disease that can affect any part of the digestive tract, including the cecum.
5. Tuberculosis: The cecum can also be affected by tuberculosis, which is a bacterial infection that primarily affects the lungs but can spread to other parts of the body.
6. Cancer: Although rare, cancer can also affect the cecum, leading to symptoms such as abdominal pain, bloating, and changes in bowel habits.

Treatment for cecal diseases depends on the specific condition and its severity. Treatment options may include antibiotics, surgery, or other medical interventions. If you are experiencing symptoms that may be related to a cecal disease, it is important to seek medical attention promptly.

Respiratory aspiration is defined as the entry of foreign materials (such as food, liquids, or vomit) into the lower respiratory tract during swallowing, which includes the trachea and lungs. This can lead to respiratory complications such as pneumonia, bronchitis, or lung abscesses. Aspiration can occur in individuals with impaired swallowing function due to various conditions like neurological disorders, stroke, or anesthesia.

Ion channels are specialized transmembrane proteins that form hydrophilic pores or gaps in the lipid bilayer of cell membranes. They regulate the movement of ions (such as sodium, potassium, calcium, and chloride) across the cell membrane by allowing these charged particles to pass through selectively in response to various stimuli, including voltage changes, ligand binding, mechanical stress, or temperature changes. This ion movement is essential for many physiological processes, including electrical signaling, neurotransmission, muscle contraction, and maintenance of resting membrane potential. Ion channels can be categorized based on their activation mechanisms, ion selectivity, and structural features. Dysfunction of ion channels can lead to various diseases, making them important targets for drug development.

Duodenal diseases refer to a range of medical conditions that affect the duodenum, which is the first part of the small intestine. Here are some examples of duodenal diseases:

1. Duodenitis: This is inflammation of the duodenum, which can cause symptoms such as abdominal pain, nausea, vomiting, and bloating. Duodenitis can be caused by bacterial or viral infections, excessive use of nonsteroidal anti-inflammatory drugs (NSAIDs), or chronic inflammation due to conditions like Crohn's disease.
2. Peptic ulcers: These are sores that develop in the lining of the duodenum, usually as a result of infection with Helicobacter pylori bacteria or long-term use of NSAIDs. Symptoms can include abdominal pain, bloating, and heartburn.
3. Duodenal cancer: This is a rare type of cancer that affects the duodenum. Symptoms can include abdominal pain, weight loss, and blood in the stool.
4. Celiac disease: This is an autoimmune disorder that causes the immune system to attack the lining of the small intestine in response to gluten, a protein found in wheat, barley, and rye. This can lead to inflammation and damage to the duodenum.
5. Duodenal diverticulosis: This is a condition in which small pouches form in the lining of the duodenum. While many people with duodenal diverticulosis do not experience symptoms, some may develop complications such as inflammation or infection.
6. Duodenal atresia: This is a congenital condition in which the duodenum does not form properly, leading to blockage of the intestine. This can cause symptoms such as vomiting and difficulty feeding in newborns.

Calcium channels are specialized proteins that span the membrane of cells and allow calcium ions (Ca²+) to flow in and out of the cell. They are crucial for many physiological processes, including muscle contraction, neurotransmitter release, hormone secretion, and gene expression.

There are several types of calcium channels, classified based on their biophysical and pharmacological properties. The most well-known are:

1. Voltage-gated calcium channels (VGCCs): These channels are activated by changes in the membrane potential. They are further divided into several subtypes, including L-type, P/Q-type, N-type, R-type, and T-type. VGCCs play a critical role in excitation-contraction coupling in muscle cells and neurotransmitter release in neurons.
2. Receptor-operated calcium channels (ROCCs): These channels are activated by the binding of an extracellular ligand, such as a hormone or neurotransmitter, to a specific receptor on the cell surface. ROCCs are involved in various physiological processes, including smooth muscle contraction and platelet activation.
3. Store-operated calcium channels (SOCCs): These channels are activated by the depletion of intracellular calcium stores, such as those found in the endoplasmic reticulum. SOCCs play a critical role in maintaining calcium homeostasis and signaling within cells.

Dysregulation of calcium channel function has been implicated in various diseases, including hypertension, arrhythmias, migraine, epilepsy, and neurodegenerative disorders. Therefore, calcium channels are an important target for drug development and therapy.

The sigmoid colon is a part of the large intestine that forms an "S"-shaped curve before it joins the rectum. It gets its name from its unique shape, which resembles the Greek letter sigma (σ). The main function of the sigmoid colon is to store stool temporarily and assist in the absorption of water and electrolytes from digestive waste before it is eliminated from the body.

Diverticulosis, colonic is a medical condition characterized by the presence of small sacs or pouches (diverticula) that form on the outer wall of the large intestine (colon). These sacs are usually found in the sigmoid colon, which is the part of the colon that is closest to the rectum.

Diverticulosis occurs when the inner layer of the colon's muscle pushes through weak spots in the outer layer of the colon wall, creating small pockets or sacs. The exact cause of diverticulosis is not known, but it may be associated with a low-fiber diet, aging, and increased pressure in the colon.

Most people with diverticulosis do not experience any symptoms, and the condition is often discovered during routine screening exams or when complications arise. However, some people may experience cramping, bloating, and changes in bowel habits.

Diverticulosis can lead to complications such as inflammation (diverticulitis), bleeding, and infection. It is important to seek medical attention if you experience symptoms such as severe abdominal pain, fever, or rectal bleeding, as these may be signs of a more serious condition.

Treatment for diverticulosis typically involves making dietary changes, increasing fiber intake, and taking medications to manage symptoms. In some cases, surgery may be necessary to remove affected portions of the colon.

The rectum is the lower end of the digestive tract, located between the sigmoid colon and the anus. It serves as a storage area for feces before they are eliminated from the body. The rectum is about 12 cm long in adults and is surrounded by layers of muscle that help control defecation. The mucous membrane lining the rectum allows for the detection of stool, which triggers the reflex to have a bowel movement.

Microradiography is a radiographic technique that uses X-rays to produce detailed images of small specimens, such as microscopic slides or individual cells. In this process, the specimen is placed in close contact with a high-resolution photographic emulsion, and then exposed to X-rays. The resulting image shows the distribution of radiopaque materials within the specimen, providing information about its internal structure and composition at a microscopic level.

Microradiography can be used for various applications in medical research and diagnosis, including the study of bone and tooth microstructure, the analysis of tissue pathology, and the examination of mineralized tissues such as calcifications or osteogenic lesions. The technique offers high resolution and contrast, making it a valuable tool for researchers and clinicians seeking to understand the complex structures and processes that occur at the microscopic level in living organisms.

Megacolon is a medical condition characterized by an abnormal dilation and/or hypomotility (decreased ability to move) of the colon, resulting in a significantly enlarged colon. It can be congenital or acquired. Congenital megacolon, also known as Hirschsprung's disease, is present at birth and occurs due to the absence of ganglion cells in the distal portion of the colon. Acquired megacolon, on the other hand, can develop in adults due to various causes such as chronic constipation, neurological disorders, or certain medications.

In both cases, the affected individual may experience symptoms like severe constipation, abdominal distention, and fecal impaction. If left untreated, megacolon can lead to complications such as perforation of the colon, sepsis, and even death. Treatment options depend on the underlying cause but may include medication, surgery, or a combination of both.

Potassium channel blockers are a class of medications that work by blocking potassium channels, which are proteins in the cell membrane that control the movement of potassium ions into and out of cells. By blocking these channels, potassium channel blockers can help to regulate electrical activity in the heart, making them useful for treating certain types of cardiac arrhythmias (irregular heart rhythms).

There are several different types of potassium channel blockers, including:

1. Class III antiarrhythmic drugs: These medications, such as amiodarone and sotalol, are used to treat and prevent serious ventricular arrhythmias (irregular heart rhythms that originate in the lower chambers of the heart).
2. Calcium channel blockers: While not strictly potassium channel blockers, some calcium channel blockers also have effects on potassium channels. These medications, such as diltiazem and verapamil, are used to treat hypertension (high blood pressure), angina (chest pain), and certain types of arrhythmias.
3. Non-selective potassium channel blockers: These medications, such as 4-aminopyridine and tetraethylammonium, have a broader effect on potassium channels and are used primarily in research settings to study the electrical properties of cells.

It's important to note that potassium channel blockers can have serious side effects, particularly when used in high doses or in combination with other medications that affect heart rhythms. They should only be prescribed by a healthcare provider who is familiar with their use and potential risks.

Zeolites are not typically a subject of medical definition, as they are naturally occurring or synthetically produced minerals used in various industrial applications. They are microporous, aluminosilicate minerals with a crystal-like structure, composed of aluminum, silicon, and oxygen tetrahedra. These minerals have a negative charge and can exchange positively charged ions, making them useful for water purification, odor control, and as catalysts in chemical reactions.

However, there is some research into the potential use of zeolites in medical applications, such as drug delivery systems or as adsorbents to remove toxins from the body. In these contexts, the definition of zeolites would be similar to their industrial definition.

Chlorides are simple inorganic ions consisting of a single chlorine atom bonded to a single charged hydrogen ion (H+). Chloride is the most abundant anion (negatively charged ion) in the extracellular fluid in the human body. The normal range for chloride concentration in the blood is typically between 96-106 milliequivalents per liter (mEq/L).

Chlorides play a crucial role in maintaining electrical neutrality, acid-base balance, and osmotic pressure in the body. They are also essential for various physiological processes such as nerve impulse transmission, maintenance of membrane potentials, and digestion (as hydrochloric acid in the stomach).

Chloride levels can be affected by several factors, including diet, hydration status, kidney function, and certain medical conditions. Increased or decreased chloride levels can indicate various disorders, such as dehydration, kidney disease, Addison's disease, or diabetes insipidus. Therefore, monitoring chloride levels is essential for assessing a person's overall health and diagnosing potential medical issues.

Ileal diseases refer to conditions that primarily affect the ileum, which is the final portion of the small intestine. The ileum plays a crucial role in nutrient absorption, particularly vitamin B12 and bile salts. Ileal diseases can cause various symptoms, including diarrhea, abdominal pain, weight loss, and malnutrition, depending on their nature and extent. Some common ileal diseases include:

1. Crohn's disease: A type of inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract, including the ileum. Crohn's disease causes chronic inflammation, which can lead to symptoms such as diarrhea, abdominal pain, and fatigue.
2. Celiac disease: An autoimmune disorder triggered by gluten ingestion in genetically susceptible individuals. In celiac disease, the immune system attacks the lining of the small intestine, including the ileum, causing inflammation and impaired nutrient absorption.
3. Intestinal tuberculosis: A bacterial infection caused by Mycobacterium tuberculosis that can affect any part of the gastrointestinal tract, including the ileum. Intestinal tuberculosis can cause symptoms such as abdominal pain, diarrhea, and weight loss.
4. Typhlitis: Also known as neutropenic enterocolitis, typhlitis is an inflammatory condition that affects the cecum and terminal ileum, typically in immunocompromised individuals. It can cause symptoms such as abdominal pain, fever, and diarrhea.
5. Meckel's diverticulum: A congenital condition characterized by a small pouch protruding from the wall of the ileum. While many people with Meckel's diverticulum do not experience symptoms, it can sometimes become inflamed or bleed, causing abdominal pain and rectal bleeding.
6. Lymphoma: A type of cancer that originates in the lymphatic system and can affect any part of the body, including the ileum. Ileal lymphoma can cause symptoms such as abdominal pain, diarrhea, and weight loss.

Explosive agents are substances or materials that can undergo rapid chemical reactions, leading to a sudden release of gas and heat, resulting in a large increase in pressure and volume. This rapid expansion creates an explosion, which can cause significant damage to surrounding structures and pose serious risks to human health and safety.

Explosive agents are typically classified into two main categories: low explosives and high explosives. Low explosives burn more slowly than high explosives and rely on the confinement of the material to build up pressure and cause an explosion. Examples of low explosives include black powder, smokeless powder, and certain types of pyrotechnics.

High explosives, on the other hand, decompose rapidly and can detonate with great speed and force. They are often used in military applications such as bombs, artillery shells, and demolitions. Examples of high explosives include TNT (trinitrotoluene), RDX (cyclotrimethylenetrinitramine), and PETN (pentaerythritol tetranitrate).

It is important to note that the handling, storage, and use of explosive agents require specialized training and strict safety protocols, as they can pose significant risks if not managed properly.

Gastrointestinal transit refers to the movement of food, digestive secretions, and waste products through the gastrointestinal tract, from the mouth to the anus. This process involves several muscles and nerves that work together to propel the contents through the stomach, small intestine, large intestine, and rectum.

The transit time can vary depending on factors such as the type and amount of food consumed, hydration levels, and overall health. Abnormalities in gastrointestinal transit can lead to various conditions, including constipation, diarrhea, and malabsorption. Therefore, maintaining normal gastrointestinal transit is essential for proper digestion, nutrient absorption, and overall health.

I'm sorry for any confusion, but "Metal Ceramic Alloys" is not a recognized medical term. It is, however, a term used in the field of materials science and engineering. Metal ceramic alloys, also known as cermets, are materials that combine properties of both metals and ceramics. They are typically composed of a metal or alloy matrix with embedded ceramic particles.

In the context of medical devices or dental restorations, the term you might be looking for is "porcelain-fused-to-metal" (PFM). PFM restorations are a type of dental crown or bridge that combines a metal substructure with a ceramic outer layer. The metal provides strength and durability, while the ceramic layer mimics the appearance of natural teeth.

If you have any questions related to medical terminology or definitions, please don't hesitate to ask!

4-Aminopyridine is a type of medication that is used to treat symptoms of certain neurological disorders, such as multiple sclerosis or spinal cord injuries. It works by blocking the action of potassium channels in nerve cells, which helps to improve the transmission of nerve impulses and enhance muscle function.

The chemical name for 4-Aminopyridine is 4-AP or fampridine. It is available as a prescription medication in some countries and can be taken orally in the form of tablets or capsules. Common side effects of 4-Aminopyridine include dizziness, lightheadedness, and numbness or tingling sensations in the hands or feet.

It is important to note that 4-Aminopyridine should only be used under the supervision of a healthcare professional, as it can have serious side effects if not used properly.

Divalent cations are ions that carry a positive charge of +2. They are called divalent because they have two positive charges. Common examples of divalent cations include calcium (Ca²+), magnesium (Mg²+), and iron (Fe²+). These ions play important roles in various biological processes, such as muscle contraction, nerve impulse transmission, and bone metabolism. They can also interact with certain drugs and affect their absorption, distribution, and elimination in the body.

"Gallopamil" is not a recognized medical term or a medication in current use. It may be a misspelling or a misunderstanding of "Gallopamil," which is the international nonproprietary name (INN) for a pharmaceutical drug known as "Diltiazem."

Diltiazem is a calcium channel blocker, a type of medication used to treat high blood pressure, angina (chest pain), and certain heart rhythm disorders. It works by relaxing the muscles of the blood vessels and slowing down the heart rate, which can help reduce the force and frequency of heart contractions and improve blood flow.

It's important to note that medications should always be taken under the guidance and supervision of a healthcare professional, who can provide accurate information about their intended uses, potential side effects, and appropriate dosages based on individual patient needs.

Melena is a medical term that refers to the passage of black, tarry stools. It's not a specific disease but rather a symptom caused by the presence of digested blood in the gastrointestinal tract. The dark color results from the breakdown of hemoglobin, the protein in red blood cells, by gut bacteria and stomach acids.

Melena stools are often associated with upper gastrointestinal bleeding, which can occur due to various reasons such as gastric ulcers, esophageal varices (dilated veins in the esophagus), Mallory-Weiss tears (tears in the lining of the esophagus or stomach), or tumors.

It is essential to differentiate melena from hematochezia, which refers to the passage of bright red blood in the stool, typically indicating lower gastrointestinal bleeding. A healthcare professional should evaluate any concerns related to changes in bowel movements, including the presence of melena or hematochezia.

The lower esophageal sphincter (LES) is a specialized ring of muscle located at the junction of the esophagus and stomach. It functions as a physiological valve that regulates the direction of content flow between the esophagus and the stomach. Normally, the LES remains contracted to prevent the reflux of gastric contents into the esophagus, and it relaxes during swallowing to allow food to enter the stomach.

A dysfunctional lower esophageal sphincter may lead to gastroesophageal reflux disease (GERD), where stomach acid frequently backs up into the esophagus, causing symptoms such as heartburn, chest pain, and difficulty swallowing.

Tetraethylammonium (TEA) is not typically defined in the context of medical terminology, but rather it is a chemical compound with the formula (C2H5)4N+. It is used in research and development, particularly in the field of electrophysiology where it is used as a blocking agent for certain types of ion channels.

Medically, TEA may be mentioned in the context of its potential toxicity or adverse effects on the human body. Exposure to TEA can cause symptoms such as nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and confusion. Severe exposure can lead to more serious complications, including seizures, respiratory failure, and cardiac arrest.

Therefore, while Tetraethylammonium is not a medical term per se, it is important for healthcare professionals to be aware of its potential health hazards and take appropriate precautions when handling or working with this compound.

Colonic polyps are abnormal growths that protrude from the inner wall of the colon (large intestine). They can vary in size, shape, and number. Most colonic polyps are benign, meaning they are not cancerous. However, some types of polyps, such as adenomas, have a higher risk of becoming cancerous over time if left untreated.

Colonic polyps often do not cause any symptoms, especially if they are small. Larger polyps may lead to symptoms like rectal bleeding, changes in bowel habits, abdominal pain, or iron deficiency anemia. The exact cause of colonic polyps is not known, but factors such as age, family history, and certain medical conditions (like inflammatory bowel disease) can increase the risk of developing them.

Regular screening exams, such as colonoscopies, are recommended for individuals over the age of 50 to detect and remove polyps before they become cancerous. If you have a family history of colonic polyps or colorectal cancer, your doctor may recommend earlier or more frequent screenings.

Abdominal radiography, also known as a KUB (kidneys, ureters, bladder) X-ray, is a medical imaging technique used to examine the abdominal cavity. It involves using ionizing radiation to produce images of the internal structures of the abdomen, including the bones, organs, and soft tissues.

The procedure typically involves the patient lying down on a table while a specialized X-ray machine captures images of the abdomen from different angles. The images produced can help doctors diagnose and monitor a variety of conditions, such as kidney stones, intestinal obstructions, and abnormalities in the spine or other bones.

Abdominal radiography is a quick, painless, and non-invasive procedure that requires little preparation on the part of the patient. However, it does involve exposure to radiation, so it is typically only used when necessary and when other imaging techniques are not appropriate.

Radiography is a diagnostic technique that uses X-rays, gamma rays, or similar types of radiation to produce images of the internal structures of the body. It is a non-invasive procedure that can help healthcare professionals diagnose and monitor a wide range of medical conditions, including bone fractures, tumors, infections, and foreign objects lodged in the body.

During a radiography exam, a patient is positioned between an X-ray machine and a special film or digital detector. The machine emits a beam of radiation that passes through the body and strikes the film or detector, creating a shadow image of the internal structures. Denser tissues, such as bones, block more of the radiation and appear white on the image, while less dense tissues, such as muscles and organs, allow more of the radiation to pass through and appear darker.

Radiography is a valuable tool in modern medicine, but it does involve exposure to ionizing radiation, which can carry some risks. Healthcare professionals take steps to minimize these risks by using the lowest possible dose of radiation necessary to produce a diagnostic image, and by shielding sensitive areas of the body with lead aprons or other protective devices.

Intestinal polyps are abnormal growths that protrude from the lining of the intestines. They can occur in any part of the digestive tract, including the colon and rectum (colorectal polyps), small intestine, or stomach. These growths vary in size, shape, and number. Most intestinal polyps are benign, meaning they are not cancerous. However, some types of polyps, such as adenomatous polyps, can become cancerous over time if left untreated.

Intestinal polyps can be asymptomatic or cause symptoms like rectal bleeding, abdominal pain, changes in bowel habits, or anemia (in cases where there is chronic, slow bleeding). The exact cause of intestinal polyps is not fully understood, but factors such as age, family history, and certain genetic conditions can increase the risk of developing them. Regular screening exams, like colonoscopies, are essential for early detection and removal of polyps to prevent potential complications, including colorectal cancer.

Stomach volvulus is a medical condition that involves the twisting or rotation of the stomach around its axis, leading to obstruction of the inflow and outflow of the stomach. This can result in strangulation of the blood supply to the stomach wall, potentially causing ischemia, necrosis, and perforation if not promptly treated. It is a surgical emergency that requires immediate medical attention. The condition can be congenital or acquired, with the acquired form being more common and often associated with underlying conditions such as gastric distention, laxity of gastrocolic ligaments, or previous abdominal surgery.

Electrophysiology is a branch of medicine that deals with the electrical activities of the body, particularly the heart. In a medical context, electrophysiology studies (EPS) are performed to assess abnormal heart rhythms (arrhythmias) and to evaluate the effectiveness of certain treatments, such as medication or pacemakers.

During an EPS, electrode catheters are inserted into the heart through blood vessels in the groin or neck. These catheters can record the electrical activity of the heart and stimulate it to help identify the source of the arrhythmia. The information gathered during the study can help doctors determine the best course of treatment for each patient.

In addition to cardiac electrophysiology, there are also other subspecialties within electrophysiology, such as neuromuscular electrophysiology, which deals with the electrical activity of the nervous system and muscles.

A diverticulum is a small sac or pouch that forms as a result of a weakness in the wall of a hollow organ, such as the intestine. These sacs can become inflamed or infected, leading to conditions like diverticulitis. Diverticula are common in the large intestine, particularly in the colon, and are more likely to develop with age. They are usually asymptomatic but can cause symptoms such as abdominal pain, bloating, constipation, or diarrhea if they become inflamed or infected.

Electric conductivity, also known as electrical conductance, is a measure of a material's ability to allow the flow of electric current through it. It is usually measured in units of Siemens per meter (S/m) or ohm-meters (Ω-m).

In medical terms, electric conductivity can refer to the body's ability to conduct electrical signals, which is important for various physiological processes such as nerve impulse transmission and muscle contraction. Abnormalities in electrical conductivity can be associated with various medical conditions, including neurological disorders and heart diseases.

For example, in electrocardiography (ECG), the electric conductivity of the heart is measured to assess its electrical activity and identify any abnormalities that may indicate heart disease. Similarly, in electromyography (EMG), the electric conductivity of muscles is measured to diagnose neuromuscular disorders.

Tetraethylammonium compounds refer to chemical substances that contain the tetraethylammonium cation (N(C2H5)4+). This organic cation is derived from tetraethylammonium hydroxide, which in turn is produced by the reaction of ethyl alcohol with ammonia and then treated with a strong acid.

Tetraethylammonium compounds are used in various biomedical research applications as they can block certain types of ion channels, making them useful for studying neuronal excitability and neurotransmission. However, these compounds have also been associated with toxic effects on the nervous system and other organs, and their use is therefore subject to strict safety regulations.

Patch-clamp techniques are a group of electrophysiological methods used to study ion channels and other electrical properties of cells. These techniques were developed by Erwin Neher and Bert Sakmann, who were awarded the Nobel Prize in Physiology or Medicine in 1991 for their work. The basic principle of patch-clamp techniques involves creating a high resistance seal between a glass micropipette and the cell membrane, allowing for the measurement of current flowing through individual ion channels or groups of channels.

There are several different configurations of patch-clamp techniques, including:

1. Cell-attached configuration: In this configuration, the micropipette is attached to the outer surface of the cell membrane, and the current flowing across a single ion channel can be measured. This configuration allows for the study of the properties of individual channels in their native environment.
2. Whole-cell configuration: Here, the micropipette breaks through the cell membrane, creating a low resistance electrical connection between the pipette and the inside of the cell. This configuration allows for the measurement of the total current flowing across all ion channels in the cell membrane.
3. Inside-out configuration: In this configuration, the micropipette is pulled away from the cell after establishing a seal, resulting in the exposure of the inner surface of the cell membrane to the solution in the pipette. This configuration allows for the study of the properties of ion channels in isolation from other cellular components.
4. Outside-out configuration: Here, the micropipette is pulled away from the cell after establishing a seal, resulting in the exposure of the outer surface of the cell membrane to the solution in the pipette. This configuration allows for the study of the properties of ion channels in their native environment, but with the ability to control the composition of the extracellular solution.

Patch-clamp techniques have been instrumental in advancing our understanding of ion channel function and have contributed to numerous breakthroughs in neuroscience, pharmacology, and physiology.

Diverticulitis, Colonic is a medical condition characterized by the inflammation or infection of one or more diverticula in the colon. Diverticula are small, bulging pouches that form in the wall of the colon, usually in older adults. They are caused by increased pressure on weakened areas of the colon wall, resulting in the formation of these sac-like protrusions.

When diverticula become inflamed or infected, it leads to the condition known as diverticulitis. Symptoms of colonic diverticulitis may include abdominal pain, fever, nausea, vomiting, constipation or diarrhea, and a decreased appetite. In severe cases, complications such as perforation, abscess formation, or peritonitis (inflammation of the lining of the abdominal cavity) may occur, requiring hospitalization and surgical intervention.

The exact cause of diverticulitis is not fully understood, but it is believed to be associated with a low-fiber diet, obesity, smoking, and lack of exercise. Treatment typically involves antibiotics to clear the infection, a liquid diet to allow the colon to rest, and over-the-counter or prescription pain medications to manage discomfort. In severe cases or in patients who experience recurrent episodes of diverticulitis, surgery may be necessary to remove the affected portion of the colon.

Cathartics are a type of medication that stimulates bowel movements and evacuates the intestinal tract. They are often used to treat constipation or to prepare the bowel for certain medical procedures, such as colonoscopies. Common cathartic medications include laxatives, enemas, and suppositories.

Cathartics work by increasing the muscle contractions of the intestines, which helps to move stool through the digestive tract more quickly. They may also increase the amount of water in the stool, making it softer and easier to pass. Some cathartics, such as bulk-forming laxatives, work by absorbing water and swelling in the intestines, which helps to bulk up the stool and stimulate a bowel movement.

While cathartics can be effective at relieving constipation, they should be used with caution. Overuse of cathartics can lead to dependence on them for bowel movements, as well as electrolyte imbalances and other complications. It is important to follow the instructions carefully when using cathartic medications and to speak with a healthcare provider if constipation persists or worsens.

An intestinal fistula is an abnormal communication or connection between the intestines (or a portion of the intestine) and another organ or the skin surface. This connection forms a tract or passage, allowing the contents of the intestines, such as digestive enzymes, bacteria, and waste materials, to leak into other body areas or outside the body. Intestinal fistulas can develop due to various reasons, including inflammatory bowel diseases (like Crohn's disease), infections, complications from surgery, radiation therapy, or trauma. They can cause symptoms such as abdominal pain, diarrhea, skin irritation, and infection. Treatment of intestinal fistulas often involves a combination of medical management, nutritional support, and surgical intervention.

Duodenal obstruction is a medical condition characterized by the blockage or impediment of the normal flow of contents through the duodenum, which is the first part of the small intestine. This blockage can be partial or complete and can be caused by various factors such as:

1. Congenital abnormalities: Duodenal atresia or stenosis, where there is a congenital absence or narrowing of a portion of the duodenum.
2. Inflammatory conditions: Duodenitis, Crohn's disease, or tumors that cause swelling and inflammation in the duodenum.
3. Mechanical obstructions: Gallstones, tumors, strictures, or adhesions (scar tissue) from previous surgeries can physically block the duodenum.
4. Neuromuscular disorders: Conditions like progressive systemic sclerosis or amyloidosis that affect the neuromuscular function of the intestines can lead to duodenal obstruction.

Symptoms of duodenal obstruction may include nausea, vomiting (often with bilious or fecal matter), abdominal pain, distention, and decreased bowel movements. Diagnosis typically involves imaging studies such as X-rays, CT scans, or upper gastrointestinal series to visualize the blockage. Treatment depends on the underlying cause but may involve surgery, endoscopic procedures, or medications to manage symptoms and address the obstruction.

Aspiration pneumonia is a type of pneumonia that occurs when foreign materials such as food, liquid, or vomit enter the lungs, resulting in inflammation or infection. It typically happens when a person inhales these materials involuntarily due to impaired swallowing mechanisms, which can be caused by various conditions such as stroke, dementia, Parkinson's disease, or general anesthesia. The inhalation of foreign materials can cause bacterial growth in the lungs, leading to symptoms like cough, chest pain, fever, and difficulty breathing. Aspiration pneumonia can be a serious medical condition, particularly in older adults or individuals with weakened immune systems, and may require hospitalization and antibiotic treatment.

Calcium channel blockers (CCBs) are a class of medications that work by inhibiting the influx of calcium ions into cardiac and smooth muscle cells. This action leads to relaxation of the muscles, particularly in the blood vessels, resulting in decreased peripheral resistance and reduced blood pressure. Calcium channel blockers also have anti-arrhythmic effects and are used in the management of various cardiovascular conditions such as hypertension, angina, and certain types of arrhythmias.

Calcium channel blockers can be further classified into two main categories based on their chemical structure: dihydropyridines (e.g., nifedipine, amlodipine) and non-dihydropyridines (e.g., verapamil, diltiazem). Dihydropyridines are more selective for vascular smooth muscle and have a greater effect on blood pressure than heart rate or conduction. Non-dihydropyridines have a more significant impact on cardiac conduction and contractility, in addition to their vasodilatory effects.

It is important to note that calcium channel blockers may interact with other medications and should be used under the guidance of a healthcare professional. Potential side effects include dizziness, headache, constipation, and peripheral edema.

"Rana catesbeiana" is the scientific name for the American bullfrog, which is not a medical term or concept. It belongs to the animal kingdom, specifically in the order Anura and family Ranidae. The American bullfrog is native to North America and is known for its large size and distinctive loud call.

However, if you are looking for a medical definition, I apologize for any confusion. Please provide more context or specify the term you would like me to define.

Esophagoscopy is a medical procedure that involves the visual examination of the esophagus, which is the tube that connects the throat to the stomach. This procedure is typically carried out using an esophagogastroduodenoscope (EGD), a flexible tube with a camera and light on the end.

During the procedure, the EGD is inserted through the mouth and down the throat into the esophagus, allowing the medical professional to examine its lining for any abnormalities such as inflammation, ulcers, or tumors. The procedure may also involve taking tissue samples (biopsies) for further examination and testing.

Esophagoscopy is commonly used to diagnose and monitor conditions such as gastroesophageal reflux disease (GERD), Barrett's esophagus, esophageal cancer, and other disorders affecting the esophagus. It may also be used to treat certain conditions, such as removing polyps or foreign objects from the esophagus.

The ileocecal valve, also known as the Bauhin's valve, is a vital physiological structure in the gastrointestinal tract. It is a valve located at the junction between the ileum (the final portion of the small intestine) and the cecum (the first part of the large intestine or colon). This valve functions to control the flow of digesta from the small intestine into the large intestine, preventing backflow from the colon into the small intestine. It is an essential component in maintaining proper digestive function and gut health.

In the context of medicine, particularly in physical therapy and rehabilitation, "pliability" refers to the quality or state of being flexible or supple. It describes the ability of tissues, such as muscles or fascia (connective tissue), to stretch, deform, and adapt to forces applied upon them without resistance or injury. Improving pliability can help enhance range of motion, reduce muscle stiffness, promote circulation, and alleviate pain. Techniques like soft tissue mobilization, myofascial release, and stretching are often used to increase pliability in clinical settings.

Fundoplication is a surgical procedure in which the upper part of the stomach (the fundus) is wrapped around the lower esophagus and then stitched into place. This procedure strengthens the lower esophageal sphincter, which helps prevent acid reflux from the stomach into the esophagus. It is commonly used to treat gastroesophageal reflux disease (GERD) and paraesophageal hernias.

Cadmium is a toxic heavy metal that is a byproduct of the mining and smelting of zinc, lead, and copper. It has no taste or smell and can be found in small amounts in air, water, and soil. Cadmium can also be found in some foods, such as kidneys, liver, and shellfish.

Exposure to cadmium can cause a range of health effects, including kidney damage, lung disease, fragile bones, and cancer. Cadmium is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC) and the National Toxicology Program (NTP).

Occupational exposure to cadmium can occur in industries that produce or use cadmium, such as battery manufacturing, metal plating, and pigment production. Workers in these industries may be exposed to cadmium through inhalation of cadmium-containing dusts or fumes, or through skin contact with cadmium-containing materials.

The general population can also be exposed to cadmium through the environment, such as by eating contaminated food or breathing secondhand smoke. Smoking is a major source of cadmium exposure for smokers and those exposed to secondhand smoke.

Prevention measures include reducing occupational exposure to cadmium, controlling emissions from industrial sources, and reducing the use of cadmium in consumer products. Regular monitoring of air, water, and soil for cadmium levels can also help identify potential sources of exposure and prevent health effects.

Endoscopy is a medical procedure that involves the use of an endoscope, which is a flexible tube with a light and camera at the end, to examine the interior of a body cavity or organ. The endoscope is inserted through a natural opening in the body, such as the mouth or anus, or through a small incision. The images captured by the camera are transmitted to a monitor, allowing the physician to visualize the internal structures and detect any abnormalities, such as inflammation, ulcers, or tumors. Endoscopy can also be used for diagnostic purposes, such as taking tissue samples for biopsy, or for therapeutic purposes, such as removing polyps or performing minimally invasive surgeries.

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