Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms underlying the defective platelet function in cirrhotic patients were investigated. Eleven cirrhotic patients with mild disease (group 1), 20 patients with severe cirrhosis (group 2), and 31 controls were studied. Platelet aggregation was significantly reduced in cirrhotics compared with controls. Compared with controls, cirrhotic patients in group 2 showed a significant reduction in the total content of adenosine triphosphate (57.8 +/- 7.8 vs. 26.1 +/- 6.3 mumol/10(11) platelets; P less than 0.05), 5-hydroxytryptamine (285 +/- 26 vs. 104 +/- 38 nmol/10(11) platelets; P less than 0.05), beta-thromboglobulin (2129 +/- 120 vs. 1223 +/- 161 ng/10(8) platelets; P less than 0.01), and platelet factor 4 (1389 +/- 108 vs. 805 +/- 176 ng/10(8) platelets; P less than 0.05). In patients with severe disease, an increase in plasma beta-thromboglobulin-platelet factor 4 ratio, an index of in vivo platelet activation, was observed (controls, 3.50 +/- 0.50; group 1, 4.02 +/- 0.80; and group 2, 6.59 +/- 1.15). Our data indicate the existence of a platelet storage pool defect, which may favor the bleeding tendency of cirrhotic patients.
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PMID:Evidence for a storage pool defect in platelets from cirrhotic patients with defective aggregation. 138 51

We measured the hemodynamic effects of intravenous vasopressin, ketanserin (a 5-hydroxytryptamine-2 receptor blocker), and vasopressin plus ketanserin in 33 patients with hepatitis B-related cirrhosis. Thirteen patients received vasopressin alone (0.66 units/min), ten patients ketanserin alone (10 mg), and ten patients vasopressin followed by vasopressin plus ketanserin. Vasopressin alone reduced the hepatic venous pressure gradient (from 18 +/- 5, mean +/- S.D., to 9 +/- 3 mmHg, p less than 0.0001) and cardiac output (p less than 0.0001), but increased mean arterial pressure (p less than 0.005), mean pulmonary arterial pressure (p less than 0.0001), pulmonary capillary wedge pressure (p less than 0.0001), and systemic vascular resistance (p less than 0.001). There was no significant change in heart rate. Ketanserin alone produced a significant fall in the hepatic venous pressure gradient (from 16 +/- 4 to 13 +/- 3 mmHg, p less than 0.0001), mean arterial pressure (p less than 0.005), mean pulmonary arterial pressure (p less than 0.005), and pulmonary capillary wedge pressure (p less than 0.005). Heart rate, cardiac output, and systemic vascular resistance were not significantly changed. The addition of ketanserin to vasopressin corrected most of the systemic hemodynamic disturbances produced by vasopressin. This combination did not lead to a further reduction in the hepatic venous pressure gradient. We conclude that intravenous ketanserin reduces portal pressure in patients with hepatitis B-related cirrhosis. The addition of ketanserin to vasopressin improves the detrimental systemic hemodynamic effects of vasopressin without further reducing the portal pressure.
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PMID:Hemodynamic effects of a combination of vasopressin and ketanserin in patients with hepatitis b-related cirrhosis. 150 56

It has been demonstrated that serotonin (5-hydroxytryptamine; 5HT) can decrease portal vascular resistance in animals and could be a possible mediator for intestinal vasodilatation. Moreover, isolated mesenteric vein from portal hypertensive rats has been shown to be hyper-responsive to 5HT. Hence 5HT may play a role in the pathophysiology of the hyperkinetic syndrome observed in patients with portal hypertension. This hypothesis that serotonin might increase splanchnic blood flow, and hence portal pressure, led us to propose that 5HT receptor antagonists might decrease portal hypertension. We observed that acute administration of ketanserin, an antagonist of serotonin at 5HT2 receptors, significantly decreased portal pressure and portal-systemic collateral blood flow in patients with cirrhosis, whereas hepatic blood flow was not modified. Arterial pressure slightly decreased, while cardiac output was not affected by ketanserin. These findings were also observed during continuous administration of ketanserin. More recently, it has been shown that ritanserin, a more specific 5HT2 receptor antagonist, significantly decreased portal pressure in cirrhotic patients. Finally, in rats with portal hypertension, ketanserin as well as ritanserin produced significant reductions in portal pressure but did not modify portal tributory blood flow. In these portal hypertensive animals, 5HT2 antagonists may act on hepatocollateral vascular resistance. These studies confirm current evidence in favor of a role for the actions of serotonin via 5HT2 receptors in portal hypertension and add a new group of substances for its treatment.
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PMID:Portal hypertension: serotonin and pathogenesis. 228 48

Gastric antral vascular ectasia is a recently recognized cause of chronic gastrointestinal blood loss. Immunohistochemical and electron-microscopic studies were performed on the surgically resected antrum of a patient with antral vascular ectasia. These revealed extraepithelial and intraepithelial neuroendocrine cell proliferations. Staining for a wide range of neural and endocrine markers demonstrated that these cells contain large quantities of 5-hydroxytryptamine and vasoactive intestinal polypeptide. Gastric vascular ectasia is of unknown etiology but has been associated with achlorhydria and liver cirrhosis. The findings suggest that locally released neurotransmitters may be responsible for local vasodilation and hence a propensity to bleed.
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PMID:Neuroendocrine cell proliferations in gastric antral vascular ectasia. 278 44

Ketanserin, a 5-hydroxytryptamine-2 receptor blocker, has been shown to decrease portal pressure in recent acute hemodynamic studies that have been performed both in experimental animals and portal hypertensive patients. The present study was designed to investigate the effects of chronic oral administration of ketanserin in portal hypertensive patients with cirrhosis. The mean baseline hepatic venous pressure gradient in the 13 patients with alcoholic cirrhosis who completed the study was 15.7 +/- 2.7 mmHg. It decreased significantly to 13.3 +/- 2.0 mmHg (p less than 0.001) after ketanserin was administered at a mean dose of 51 mg per day for a mean period of 32 days. This 14.6% reduction in hepatic venous pressure gradient resulted mainly from a decrease in mean wedged hepatic venous pressure (from 22.2 +/- 4.0 to 20.1 +/- 3.6 mmHg) and was accompanied by significant decreases in cardiac index (18.8%) and in mean arterial pressure (8.1%). However, changes in cardiac index or in mean arterial pressure were not predictive of modifications in the hepatic venous pressure gradient. Eight of 16 patients entered in the study developed side effects, the most significant being a reversible portosystemic encephalopathy, which occurred in three patients who had poor liver function. This study confirms evidence in favor of a role for 5-hydroxytryptamine in portal hypertension and adds a new group of agents for the chronic treatment of portal hypertensive patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Long-term hemodynamic effects of ketanserin, a 5-hydroxytryptamine blocker, in portal hypertensive patients. 290 73

Serotoninergic mechanisms are thought to play a role in portal hypertension. Because this biomine is metabolized by the liver, peripheral blood and plasma levels of 5-hydroxytryptamine and 5-hydroxyindole acetic acid (the main metabolite of 5-hydroxytryptamine) were measured in 30 patients with cirrhosis. Whole-blood 5-hydroxytryptamine levels were significantly lower in patients with cirrhosis (158 +/- 28 nM) than in age-matched controls (332 +/- 19 nM), and no correlation was found between these levels and the severity of cirrhosis. Unconjugated plasma 5-hydroxytryptamine levels, an indication of the active form of 5-hydroxytryptamine, were significantly higher in patients with cirrhosis than in controls (6.8 +/- 1.7 nM and 3.4 +/- 0.5 nM, respectively), and in patients with cirrhosis these levels were higher in Pugh grade A than in Pugh grade C patients. Conjugated-plasma 5-hydroxytryptamine levels were not significantly different between patients with cirrhosis (32.2 +/- 8.1 nmol/L) and controls (16.4 +/- 1.4 nmol/L). Plasma 5-hydroxyindole acetic acid was significantly lower in patients with cirrhosis than in controls (1.5 +/- 0.1 nmol/L and 2.3 +/- 0.1 nmol/L, respectively). In conclusion, this study shows that serotoninergic mechanisms are altered in patients with cirrhosis.
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PMID:Blood and plasma 5-hydroxytryptamine levels in patients with cirrhosis. 752 65

The pharmacokinetics of fluvoxamine, a selective serotonin reuptake inhibitor (SSRI) with antidepressant properties, are well established. After oral administration, the drug is almost completely absorbed from the gastrointestinal tract, and the extent of absorption is unaffected by the presence of food. Despite complete absorption, oral bioavailability in man is approximately 50% on account of first-pass hepatic metabolism. Peak plasma fluvoxamine concentrations are reached 4 to 12 hours (enteric-coated tablets) or 2 to 8 hours (capsules, film-coated tablets) after administration. Steady-state plasma concentrations are achieved within 5 to 10 days after initiation of therapy and are 30 to 50% higher than those predicted from single dose data. Fluvoxamine displays nonlinear steady-state pharmacokinetics over the therapeutic dose range, with disproportionally higher plasma concentrations with higher dosages. Plasma fluvoxamine concentrations show no clear relationship with antidepressant response or severity of adverse effects. Fluvoxamine undergoes extensive oxidative metabolism, most probably in the liver. Nine metabolites have been identified, none of which are known to be pharmacologically active. The specific cytochrome P450 (CYP) isoenzymes involved in the metabolism of fluvoxamine are unknown. CYP2D6, which is crucially involved in the metabolism of paroxetine and fluoxetine, appears to play a clinically insignificant role in the metabolism of fluvoxamine. The drug is excreted in the urine, predominantly as metabolites, with only negligible amounts ( < 4%) of the parent compound. Fluvoxamine shows a biphasic pattern of elimination with a mean terminal elimination half-life of 12 to 15 hours after a single oral dose; this is prolonged by 30 to 50% at steady-state. Plasma protein binding of fluvoxamine (77%) is low compared with that of other SSRIs. Fluvoxamine pharmacokinetics are substantially unaltered by increased age or renal impairment. However, its elimination is prolonged in patients with hepatic cirrhosis. Fluvoxamine inhibits oxidative drug metabolising enzymes (particularly CYP1A2, and less potently and much less potently CYP3A4 and CYP2D6, respectively) and has the potential for clinically significant drug interactions. Drugs whose metabolic elimination is impaired by fluvoxamine include tricyclic antidepressants (tertiary, but not secondary, amines), alprazolam, bromazepam, diazepam, theophylline, propranolol, warfarin and, possibly, carbamazepine. Fluvoxamine is a second generation antidepressant that selectively inhibits neuronal reuptake of serotonin (5-hydroxytryptamine; 5-HT). Fluvoxamine exhibits antidepressant activity similar to that of the tricyclic antidepressants, but has a somewhat improved tolerability profile, particularly with respect to a lower incidence of anticholinergic effects and reduced cardiotoxic potential. However, gastrointestinal adverse effects, especially nausea, are seen more frequently with fluvoxamine than with the tricyclic antidepressants. Fluvoxamine does not have an asymmetric carbon in its structure (fig. 1) and therefore does not exist as optical isomers. For this reason, the potentially confounding problem of stereoisomerism does not arise with fluvoxamine.
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PMID:Overview of the pharmacokinetics of fluvoxamine. 884 17

Hepatic encephalopathy is a frequent complication of cirrhosis. Abnormalities of 5-hydroxytryptamine (5-HT) and its metabolites are recognized and may contribute to its pathogenesis. We therefore studied the effect of an oral tryptophan load (6-18 g) upon psychometric test scores and analyzed EEG's in alcoholic cirrhotic patients. Eight patients had had previous encephalopathic episodes related to variceal bleeds and one patient was awaiting a liver transplant. Five out of the 10 patients had at least one abnormal baseline psychometric test. Following tryptophan challenge there were no changes in blood ammonia but plasma tryptophan levels were elevated approximately 10-fold (p < 0.01 x 10(-7)). Nevertheless, there were no statistically significant changes in psychometric testing or analyzed EEG frequency distribution. All patients reported nausea or vomiting while one patient developed a short-lived serotonin like syndrome. We conclude that in this group of patients, an oral tryptophan load does not induce or worsen subclinical hepatic encephalopathy. If the high blood levels of tryptophan seen in these studies are able to influence cerebral neurotransmitter synthesis, the results do not support a primary role for abnormalities of 5-HT neurotransmission in hepatic encephalopathy.
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PMID:Oral tryptophan challenge studies in cirrhotic patients: no evidence of neuropsychiatric changes. 1456 68

The human cardiovascular system is exposed to plasma 5-hydroxytryptamine (5-HT, serotonin), usually released from platelets. 5-HT can produce harmful acute and chronic effects. The acute cardiac effects of 5-HT consist of tachycardia (preceded on occasion by a brief reflex bradycardia), increased atrial contractility and production of atrial arrhythmias. Acute inotropic, lusitropic and arrhythmic effects of 5-HT on human ventricle become conspicuous after inhibition of phosphodiesterase (PDE) activity. Human cardiostimulation is mediated through 5-HT4 receptors. Atrial and ventricular PDE3 activity exerts a protective role against potentially harmful cardiostimulation. Chronic exposure to high levels of 5-HT (from metastatic carcinoid tumours), the anorectic drug fenfluramine and its metabolites, as well as the ecstasy drug 3,4-methylenedioxymethamphetamine (MDMA) and its metabolite 3,4-methylenedioxyamphetamine (MDA) are associated with proliferative disease and thickening of cardiac valves, mediated through 5-HT2B receptors. 5-HT2B receptors have an obligatory physiological role in murine cardiac embryology but whether this happens in humans requires research. Congenital heart block (CHB) is, on occasion, associated with autoantibodies against 5-HT4 receptors. Acute vascular constriction by 5-HT is usually shared by 5-HT1B and 5-HT2A receptors, except in intracranial arteries which constrict only through 5-HT1B receptors. Both 5-HT1B and 5-HT2A receptors can mediate coronary artery spasm but only 5-HT1B receptors appear involved in coronary spasm of patients treated with triptans or with Prinzmetal angina. 5-HT2A receptors constrict the portal venous system including oesophageal collaterals in cirrhosis. Chronic exposure to 5-HT can contribute to pulmonary hypertension through activation of constrictor 5-HT1B receptors and proliferative 5-HT2B receptors, and possibly through direct intracellular effects.
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PMID:5-hydroxytryptamine receptors in the human cardiovascular system. 1696 Sep 82

Broilers are susceptible to pulmonary hypertension syndrome (PHS; ascites syndrome) when their pulmonary vascular capacity is anatomically or functionally inadequate to accommodate the requisite cardiac output without an excessive elevation in pulmonary arterial pressure. The consequences of an inadequate pulmonary vascular capacity have been demonstrated experimentally and include elevated pulmonary vascular resistance (PVR) attributable to noncompliant, fully engorged vascular channels; sustained pulmonary arterial hypertension (PAH); systemic hypoxemia and hypercapnia; specific right ventricular hypertrophy, and right atrioventricular valve failure (regurgitation), leading to central venous hypertension and hepatic cirrhosis. Pulmonary vascular capacity is broadly defined to encompass anatomical constraints related to the compliance and effective volume of blood vessels, as well as functional limitations related to the tone (degree of constriction) maintained by the primary resistance vessels (arterioles) within the lungs. Surgical occlusion of 1 pulmonary artery halves the anatomical pulmonary vascular capacity, doubles the PVR, triggers PAH, eliminates PHS-susceptible broilers, and reveals PHS-resistant survivors whose lungs are innately capable of handling sustained increases in pulmonary arterial pressure and cardiac output. We currently are using i.v. microparticle injections to increase the PVR and trigger PAH sufficient in magnitude to eliminate PHS-susceptible individuals while allowing PHS-resistant individuals to survive as progenitors of robust broiler lines. The microparticles obstruct pulmonary arterioles and cause local tissues and responding leukocytes to release vasoactive substances, including the vasodilator NO and the highly effective vasoconstrictors thromboxane A(2) and serotonin [5-hydroxytryptamine (5-HT)]. Nitric oxide is the principal vasodilator responsible for modulating (attenuating) the PAH response and ensuing mortality triggered by i.v. microparticle injections, whereas microparticle-induced increases in PVR can be attributed principally to 5-HT. Our observations support the hypothesis that susceptibility to PHS is a consequence of anatomically inadequate pulmonary vascular capacity combined with the functional predominance of the vasoconstrictor 5-HT over the vasodilator NO. The contribution of TxA(2) remains to be determined. Selecting broiler lines for resistance to PHS depends upon improving both anatomical and functional components of pulmonary vascular capacity.
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PMID:An inadequate pulmonary vascular capacity and susceptibility to pulmonary arterial hypertension in broilers. 1743 37


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