Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Juvenile rats fed a diet containing 1% lead acetate for 7 weeks, in addition to an impaired growth rate and renal function derangements, suffered malabsorption of glucose and certain amino acids, as assessed by an in vivo perfusion technique. The reduction in glucose absorption ranged between 10% and 31% when the carbohydrate was pumped in concentrations of 2-80 mM. This alteration was compatible with a noncompetitive type of transport inhibition. The intestinal absorption of glycine, lysine, and phenylalanine were, respectively, decreased 22, 18, and 15% when these amino acids were present at 1 mM levels. Sodium transport was severely reduced (57.6 +/- 17.9 (SEM) vs. 124.2 +/- 17.4 muEq/min-cm) and intestinal mucosa (Na+-K+)-ATPase was concomitantly lower in the lead-intoxicated rats (186.4 +/- 19.0 vs 268.4 +/- 29.8 nmol P/min-mg protein). However, this enzyme was not altered in liver and kidney. Furthermore, intestinal mucosa fructose-1,6-diphosphatase, succinic dehydrogenase, pyruvate kinase, and tryptophan hydroxylase were not different in experimental and control animals. These studies substantiate the presence of functional and biochemical abnormalities in the intestinal mucosa of young rats when fed substantial amounts of a soluble lead salt. It is, therefore, reasonable to accept the possibility that physiologic damage occurs in tissues directly subjected to high and persistent levels of a toxic agents, as it occurs in other organs, underscoring the parallelism between transport mechanisms at the renal and intestinal levels.
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PMID:Experimental lead poisoning and intestinal transport of glucose, amino acids, and sodium. 13 38

Vasopressin and its analogs are used inthe treatment of bleeding esophageal varices. Since gastrointestinal reflux may have a deleterious effect on variceal hemorrhage, the effect of 2,3-phenylalanine-8-lysine-vasopressin upon the lower esophageal sphincter (LES) was studies by rapid pull-through manometry in 24 persons. PLV infusion up to a dosis of 2.7 mU/kg/h raised LES pressure from 15.1 +/- 1.3 (SEM) to 17.9 +/- 2.0 mm Hg. Higher doses lowered LES pressure progressively to 12.1 +/- 0.7 mmHg at 54 mU/kg/h. The serum gastrin level did neither correlate with basal LES pressure not with LES pressure changes during PLV infusion. Therefore, PLV does not appear to act indirectly through serum gastrin. Because of the danger of systemic side effects and of the undesirable in LES pressure with the usual high doses of vasoactive substances, a continuous infusion of lower doses of vasopressin analogs appears to be advantageous.
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PMID:[Effect of phenylalanine-vasopressin on the lower esophageal sphincter. Possible implications in the treatment of bleeding esophageal varices]. 108 43

The FEV1 and urinary leukotriene E4 (LTE4) concentrations were determined in six aspirin-sensitive and six non-aspirin-sensitive asthmatic subjects before and after inhalation challenge with lysine-aspirin or placebo solution. Lysine-aspirin produced a mean fall in FEV1 of 26.7 +/- 4.9% (mean +/- SEM) in subjects with aspirin sensitivity and of 8.5 +/- 6.5% (mean +/- SEM) in non-aspirin-sensitive asthmatic subjects. The mean baseline urinary LTE4 concentration of 83 pg/mg creatinine (geometric mean [GM], range 15 to 326 pg/mg creatinine) in aspirin-sensitive subjects was significantly higher than the 33.8 pg/mg creatinine (GM, range 10 to 111 pg/mg creatinine) in non-aspirin-sensitive subjects (p = 0.02). In aspirin-sensitive subjects, inhalation challenge with lysine-aspirin produced a significant increase in urinary LTE4 concentration to 240 pg/mg creatinine (GM, range 60 to 1,113 pg/mg creatine), which was not observed after placebo challenge. There was no significant change in urinary LTE4 concentration after inhalation challenge with either lysine-aspirin or placebo solution in non-aspirin-sensitive asthmatic subjects. Thus, sulfidopeptide leukotrienes are released after inhalation of lysine-aspirin in aspirin-sensitive asthmatic patients.
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PMID:Urinary leukotriene E4 after lysine-aspirin inhalation in asthmatic subjects. 133 41

Plasma renin activity (PRA), urinary excretions of PGE2, 6-keto-PGF1 alpha (6KPGF), TXB2 and renal function were determined in healthy women both in normal potassium balance (N, n = 14) and in experimental potassium depletion (KD). KD was induced by natriuretic treatment--associated to replacement of net NaCl and water losses--in the presence of either normal (congruent to 50 mmol/d) or low (less than or equal to 10 mmol/d) dietary potassium intake. By using different depletive patterns, three groups with estimated cumulative potassium deficit (mean +/- SEM) of 124 +/- 38 (KD0, n = 8), 160 +/- 43 (KD1, n = 8) and 198 +/- 22 mmol (KD2, n = 6), respectively, were obtained. Renal function by the clearance (cl.) method and urinary prostanoid concentrations by the RIA method were estimated during hypotonic polyuria (oral water load) and subsequent moderate antidiuresis induced by a low-dose infusion of lysine-8-vasopressin. 1. In KD0 group the potassium depletive treatment was inefficacious in significantly reducing either the plasma potassium concentration (PK) or the urinary potassium excretion (UKV). The reductions of PK and UKV as well as the enhancement of PRA became significant in KD1 and KD2 groups. 2. The urinary prostanoid excretions were not significantly changed in the KD0 and KD1 groups while in the KD2 group they were reduced, mainly concerning the urinary 6KPGF excretion. 3. Furthermore in the KD2 group, with larger potassium depletion, some of the typical hypokalemic renal dysfunctions appeared. The data suggest that a pathophysiologically critical degree of potassium depletion is associated with an inhibited renal prostanoid synthesis as well as an increased renin secretion.
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PMID:Urinary prostanoid excretion in healthy women with different degrees of induced potassium depletion. 163 Nov 74

rt-PA P47G, K49N, a substitution variant of recombinant human tissue-type plasminogen activator (rt-PA), in which proline at position 47 and lysine at position 49 were replaced by glycine and asparagine respectively, was previously described by Ahern et al. (J Biol Chem 1990; 265:5540-5) to have an extended in vivo half-life with unaltered in vitro fibrinolytic properties. Because this variant might possess an increased in vivo thrombolytic potency, we have constructed its cDNA, expressed it in Chinese hamster ovary cells and determined its biochemical, thrombolytic and pharmacokinetic properties relative to those of home-made rt-PA and of alteplase (Actilyse). The specific fibrinolytic activities on fibrin plates were 160,000 +/- 17,000, 210,000 +/- 88,000 and 460,000 +/- 72,000 IU/mg (mean +/- SEM) for rt-PA P47G, K49N, rt-PA and alteplase, respectively, while the catalytic efficiencies for plasminogen activation (k2/Km) in the absence of fibrin were comparable (1.1 to 1.7 x 10(-3) microM-1s-1). Fibrin enhanced the rate of plasminogen activation by rt-PA P47G, K49N 100-fold and by both wild-type molecules 390-fold. Binding of the variant rt-PA to fibrin was significantly reduced, but its affinity for lysine-Sepharose was unaltered. In an in vitro clot lysis system, consisting of a radiolabeled human plasma clot submersed in plasma, 50% clot lysis in 2 h required 0.67 +/- 0.14 micrograms/ml rt-PA P47G, K49N, 0.36 +/- 0.01 micrograms/ml rt-PA and 0.17 +/- 0.01 micrograms/ml alteplase, respectively (mean +/- SEM; n = 3 or 4). At these doses residual fibrinogen levels at 2 h were in excess of 80%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biochemical, thrombolytic and pharmacokinetic properties of rt-PA P47G, K49N, a substitution variant of human tissue-type plasminogen activator. 163 93

Over a 21-d period, 400 [four rats/level, 10 levels/amino acid, 10 indispensable amino acids (IAA)] male weanling rats (65.9 +/- 0.3 g; mean +/- SEM) were fed diets with one of 10 levels of each of the 10 IAA. In addition, four rats were fed an amino acid-free diet and 16 rats were killed on d 0 for individual body composition. With the exception of the limiting amino acid (LAA), an increment (35% of the requirement) of each IAA was added to the mixture to insure that the LAA remained first limiting. A four-parameter logistic equation was used to describe the nitrogen and weight gain responses of rats to each IAA. Conservation of nitrogen, defined as a predicted y-intercept value greater than the value observed for rats fed an amino acid-free diet (-0.304 +/- 0.023 g N/21 d), was seen when diets devoid of total aromatic amino acids or lysine (-0.062 +/- 0.013 g N/21 d) or histidine, leucine, tryptophan or valine (-0.115 +/- 0.011 g N/21 d) were fed. When total sulfur amino acids were first limiting, diminishing returns (a decrease in the first derivative) was evident from zero intake to Rmax (estimated asymptotic response maximum). In contrast, when other IAA were limiting, diminishing returns were apparent after approximately the first third of the full response. Based on the first derivative of the response curves, the efficiency of nitrogen gain depends on the LAA. The dietary LAA would be expected to influence the shape of the response curve and therefore influence the quantitative aspects of diminishing returns.
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PMID:Use of a four-parameter logistic equation to evaluate the response of growing rats to ten levels of each indispensable amino acid. 194 Nov 79

1. Oxytocin receptors in the uterus of the brushtail possum (T. vulpecula) were characterized by radioreceptor assay and compared with those of the sheep and rat uterus. 2. A single oxytocin binding site was found with an affinity (Kd) and receptor concentration (Ro) of 3.0 +/- 0.8 nmol/l and 200 +/- 60 fmol/mg protein, respectively (SEM; n = 5). The receptor was stable at -20 degrees C; divalent ions were required for optimum binding. 3. Competitive displacement curves with related peptides showed the following order of specificity: vasotocin greater than oxytocin greater than mesotocin = arginine-vasopressin = [Thr4, Gly7]-oxytocin greater than lysine-vasopressin = isotocin much greater than [d(CH2)5, D-Phe2, Ile4, Ala9-NH2]-AVP. 4. It was concluded that oxytocin receptors in the possum have similar characteristics to those of placental mammals.
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PMID:Uterine oxytocin receptors in an Australian marsupial, the brushtail possum, Trichosurus vulpecula. 196 6

The acute GH release stimulated by the synthetic hexapeptide, His-DTrp-Ala-Trp-DPhe-Lys-NH2 [GH releasing peptide (GHRP)], was determined in 18 normal men and compared with the effects of GH-releasing hormone, GHRH-(1-44)-NH2. Specificity of effect was assessed by measurement of serum PRL, LH, TSH, and cortisol. GHRP was administered at doses of 0.1, 0.3, and 1.0 microgram/kg by iv bolus. GHRH at a dose of 1.0 microgram/kg was administered alone and together with various does of GHRP. No adverse clinical effects of laboratory abnormalities were observed in response to GHRP. A side-effect of mild facial flushing of 1- to 3-min duration occurred in 16 of the 18 subjects who received GHRH-(1-44)-NH2. Mean (+/- SEM) peak serum GH levels after injection of placebo and 0.1, 0.3, and 1.0 microgram/kg GHRP were 1.2 +/- 0.3, 7.6 +/- 2.5, 16.5 +/- 4.1, and 68.7 +/- 15.5 micrograms/L, respectively. The submaximal dosages of 0.1 and 0.3 microgram/kg GHRP plus 1 microgram/kg GHRH stimulated GH release synergistically. Serum PRL and cortisol levels rose about 2-fold above basal levels only at the 1 microgram/kg dose of GHRP, and there were no changes in serum LH and TSH over the first hour after administration of the peptide(s). GHRP is a potent secretagogue of GH in normal men. Since GHRP and GHRH together stimulate GH release synergistically, these results suggest that GHRP and GHRH act independently. This supports our hypothesis that the GH-releasing activity of GHRP reflects a new physiological system in need of further characterization in animals and man.
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PMID:Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. 210 87

Plasma carnitine levels were determined in 17 patients maintained on long-term total parenteral nutrition (TPN) for a mean (+/- SEM) period of 69 +/- 11 months (range 12-196). All had severe malabsorption and were dependent on intravenous feeding. Plasma carnitine was determined by a modified Cederblad enzymatic method. Mean plasma carnitine was significantly below the mean normal for females (p less than 0.02) and borderline low for males (p = 0.07). In six patients the levels were below the low normal range, and in five others they were at the lowest levels of normal. Of the six patients with normal levels, three had elevated serum creatinine, indicating renal dysfunction which may by itself elevate plasma carnitine. In 10 patients the plasma levels of lysine (a carnitine precursor) were determined and found to be lower than normal (p less than 0.05). Plasma carnitine levels correlated positively with serum albumin (r = 0.62, p less than 0.05), and negatively with serum alkaline phosphatase (r = -0.64, p less than 0.05). Thus, patients maintained on long-term TPN may have low plasma carnitine, which could represent carnitine deficiency. The low plasma carnitine may be related to a deficiency of the carnitine precursor lysine. Further studies are required to determine the significance of the low plasma carnitine and whether carnitine supplementation should be required in long-term TPN.
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PMID:Low plasma carnitine in patients on prolonged total parenteral nutrition: association with low plasma lysine. 211 37

Human peripheral blood monocytes/macrophages derived from normal donors, patients of tuberculoid leprosy (BT/TT) and lepromatous leprosy (BL/LL) were assayed for stimulated phagocytic responses to the potent macrophage stimulator "Tuftsin" (NH2-Thr-Lys-Pro-Arg-OH) after varying periods (6 h to 14 days) of culture in vitro. The assays consisted of visual scoring of ingested Mycobacterium leprae and radiometric measurement of ingested 14C-acetate labelled Staphylococcus aureus and Mycobacterium tuberculosis (H37Ra). While normal and BT/TT macrophages showed a progressively increasing ability for tuftsin-stimulated phagocytosis with increasing age of culture in vitro, BL/LL macrophages showed the opposite response so that 14-day cultures were refractory to a stimulatory dose of up to 7.0 microM (10 to 20 times the optimal dose for normal and BT/TT macrophages). The 14-day BL/LL macrophage cultures were, however, responsive to 35 microM tuftsin (100 times the optimal dose for normal macrophages). Analysis of the dose-response curves also indicates that BT/TT cultures despite exhibiting an apparent similarity to normal macrophages demonstrate a rightward shift for a maximal stimulated phagocytosis. Finally SEM photo-micrographs of 14-day macrophage cultures of the three groups revealed that while normal and BT/TT cultures demonstrated an increase in membrane ruffling and filopodia on stimulation with 0.8 microM tuftsin, BL/LL cultures exhibited none of the features associated with stimulation. From the above findings, we conclude that lepromatous macrophages may display an aberrant differentiation profile leading to a terminal state of unresponsiveness and that the defect may possibly lie at the level of tuftsin receptor expression or transmembrane signal transduction.
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PMID:Modulation of human lepromatous monocyte-macrophage functions in vitro by tuftsin. 229 63


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