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)

1. The initial rate of L-lysine influx into erythrocytes from 13 patients with chronic renal failure has been measured using 14C-labelled lysine. Ten patients were on maintenance haemodialysis and three had never been dialysed. The results are compared with data obtained from 12 normal individuals. 2. The rate of lysine influx into washed cells from buffered saline containing 0.02-0.5 mmol of L-lysine/l has been calculated. The results can be fitted with a model in which influx has a single saturable component obeying Michaelis-Menten kinetics, and a linear non-saturable component. 3. In uraemic erythrocytes the saturable component had a mean Vmax. of 0.762 mmol h-1 litre-1 of cells (n = 13, SEM 0.072) and a mean Km of 68.2 mumol/l (SEM 5.7). These values in normal erythrocytes were 0.566 mmol h-1 litre-1 of cells (n = 12, SEM 0.033) and 70.5 mumol/l (SEM 4.1), respectively. The mean apparent diffusion constant (KD) for the linear component of influx was 0.224 h-1 (SEM 0.039) in uraemic cells and 0.178 h-1 (SEM 0.028) in normals. 4. The 35% increase in mean Vmax seen in uraemic erythrocytes was statistically significant (P = 0.02). A similar increase in Vmax. in uraemic cells compared with controls was seen in erythrocytes which were studied in zero-trans conditions after depletion of intracellular amino acids. The mean values of Km and KD were not significantly different in uraemia. The origins of this increased membrane transport capacity for lysine in uraemia are discussed.
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PMID:Increased lysine transport capacity in erythrocytes from patients with chronic renal failure. 249 48

A sensitive, specific and reproducible radioimmunoassay was developed for the measurement of alpha-melanocyte-stimulating hormone (alpha-MSH) in the blood plasma of rat. The assay method is based on a sensitive antiserum raised against alpha-MSH in rabbit. The serum is highly specific to alpha-MSH; a HPLC study of an extract of rat plasma showed that the immunoreactivity was given by alpha-MSH. The basal level of alpha-MSH, measured after a simple extraction with ethanol, was found to be 168.3 +/- 16.3 pg/ml (mean +/- SEM). Ether and lysine-vasopressin appeared to be potent stimuli for the peripheral release of alpha-MSH.
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PMID:Specific radioimmunoassay of alpha-melanocyte-stimulating hormone in rat plasma. 254 36

The kinetics of appearance of amino acids (AA) in portal blood following the ingestion of casein or rapeseed protein were compared. Six pigs, fitted with permanent catheters in the portal vein and in the carotid artery, as well as with an electromagnetic flow probe around the portal vein, received three 800 g test meals, one containing 12% rapeseed proteins (RA12) and the others containing 12% and 24% casein (CA12 and CA24), at 1-week intervals and according to a double Latin square design. Portal and arterial blood samples were collected and portal blood flow rate was recorded for 8 h after the test meals. At the end of measurement, an average of 76.1 +/- 5.6% (mean +/- SEM) of total AA from the CA24 diet had appeared in portal blood, compared with 94.3 +/- 10.4% for the CA12 diet and 103.5 +/- 12.6% for the RA12 diet. Similar results were obtained for essential AA. Differences were found in the kinetics of appearance of individual AA. Eight hours after the meal, 79% of lysine, 84% of methionine, and 73% of valine from the CA24 diet had appeared in portal blood compared, respectively, with 100, 89, and 83% from the CA12 diet and 99, 86, and 106% from the RA12 diet. Arginine from rapeseed had a net appearance level lower (82%) than the overall mixture of essential AA. With casein diets, the net appearance of arginine reached 97% (CA12) and 82% (CA24). Following the ingestion of rapeseed proteins, there seemed to be a significant appearance of endogenous AA in portal blood.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Net appearance of amino acids in portal blood during the digestion of casein or rapeseed proteins in the pig. 262 81

The gene encoding outer capsid protein VP3 of subpopulations of two animal rotaviruses, simian SA11 and Nebraska calf diarrhea virus (NCDV), was analyzed. Two laboratory strains of simian SA11 rotavirus (SA11-SEM and SA11-FEM) differed with respect to VP3. This dimorphism was indicated by a difference in electrophoretic mobility and a difference in reactivity with anti-VP3 monoclonal antibodies. The overall VP3 amino acid homology between the two SA11 VP3 proteins was 82.7%, whereas the VP3 protein of SA11-FEM was 98.5% homologous in amino acid sequence to NCDV VP3, suggesting that SA11-FEM VP3 was derived by gene reassortment in the laboratory during contamination with a bovine rotavirus. A comparison of the deduced amino acid sequence of the VP3 of two virulent NCDV strains and an attenuated NCDV strain (RIT 4237), revealed only five amino acid differences which were scattered throughout the protein but did not involve the trypsin cleavage sites. Of interest, the VP3 of the standard strain of NCDV which is virulent for cows differed in only one amino acid (position 23, Gln to Lys) from the VP3 of an NCDV mutant which was attenuated both for cows and for children.
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PMID:Comparative analysis of the VP3 gene of divergent strains of the rotaviruses simian SA11 and bovine Nebraska calf diarrhea virus. 284 21

The binding characteristics of [3H]oxytocin [( 3H]OT) and [3H]lysine vasopressin [( 3H]LVP) to nonpregnant human myometrium were investigated. Binding of both radioligands was saturable, time dependent, and reversible. Whereas [3H]OT was found to bind to a single class of sites with high affinity [Kd, 1.5 +/- 0.4 (+/- SEM) nM] and low capacity [maximum binding (Bmax), 34 +/- 6 fmol/mg protein], [3H]LVP bound to two classes of sites, one with high affinity (Kd, 2.2 +/- 0.1 nM) and low capacity (Bmax, 198 +/- 7 fmol/mg protein) and another with low affinity (Kd, 655 +/- 209 nM) and high capacity (Bmax, 5794 +/- 1616 fmol/mg protein). The binding of the labeled peptides also displayed a marked difference in sensitivity to Mg2+ and guanine nucleotides. These differences in binding characteristics as well as the differences in potency of analogs in competing for [3H]OT and [3H]LVP binding indicate the presence of distinct receptors for OT and vasopressin in human myometrium. Pharmacological characterization of the high affinity binding sites for [3H]LVP indicated that these are of the V1 subtype. Although, as suggested by others, vasopressin and OT can bind to the same sites, the presence of distinct receptors for both peptides provides an explanation for the previously reported difference in myometrial responsiveness to OT and vasopressin.
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PMID:Oxytocin and vasopressin: distinct receptors in myometrium. 303 5

Cultured IM-9 lymphocytes were preincubated with 1 microM insulin, a condition resulting in a 56% reduction in cell surface insulin receptors. Cellular proteins were then metabolically labeled, and the radioactivity incorporated into the insulin proreceptor and receptor mature subunits was measured over a 4-hr chase period. As early as 30 min of chase, incorporation into the proreceptor was 28 +/- 6% higher in down-regulated cells than in control cells (mean +/- SEM, P less than 0.05). By 1 hr of chase, the difference reached 41 +/- 14% for the proreceptor and 84 +/- 28% for the alpha subunit (P less than 0.01); values returned to normal by 2 hr. At 4 hr of chase, labeling of the alpha subunit of down-regulated cells was diminished 36 +/- 9% below control (P less than 0.05). The increased biosynthetic rate of the proreceptor was more prominent when the chase medium contained 25 microM monensin, an inhibitor of processing of the proreceptor into mature subunits. Similar effects occurred whether [3H]mannose or [3H]lysine was used as biosynthetic marker. The effect was specific for the insulin receptor. These data demonstrate that insulin receptor homologous down-regulation is associated with increased proreceptor biosynthesis and processing into mature subunits. This might represent a cellular mechanism compensating for insulin-induced receptor loss.
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PMID:Homologous down-regulation of the insulin receptor is associated with increased receptor biosynthesis in cultured human lymphocytes (IM-9 line). 309 91

The role of circulating bradykinin in the regulation of cardiovascular homeostasis was studied in the normotensive conscious rat using a competitive antagonist of bradykinin at the receptor level. This antagonist (B4162) was administered intravenously as a bolus dose of 400 micrograms. This dose was shown to effectively block the hypotensive effect of exogenous bradykinin (2.5 micrograms) for at least 5 min. The bradykinin antagonist was administered at the end of an infusion of angiotensin II (1 ng/min, n = 5, or 12.5 ng/min, n = 6), of methoxamine (0.5 micrograms/min, n = 5, or 4 micrograms/min, n = 6), of lysine vasopressin (0.25 mUI/min, n = 11) or of saline (10 microliter/min, n = 7). The bradykinin antagonist did not change the mean arterial pressure of the control rats. The low doses of angiotensin II and of methoxamine did not have an effect on mean blood pressure. The bradykinin antagonist however increased mean blood pressure of these rats within 1 min by 10 +/- 2 (p less than 0.01, mean +/- SEM) and by 12 +/- 3 (p less than 0.01) mmHg, respectively. The large dose of angiotensin II raised mean blood pressure from 127 +/- 3.6 to 142 +/- 4.9 mmHg and that of methoxamine from 130 +/- 2 to 146 +/- 5 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Attenuation of the vasopressor effect of angiotensin II, vasopressin and alpha 1-adrenergic stimulation by bradykinin]. 311 81

Exposure of porcine vascular smooth muscle cells to platelet-derived growth factor (PDGF; 18-180 ng/ml) but not epidermal growth factor (EGF; 30 ng/ml), somatomedin C (SmC; 30 ng/ml), or insulin (10 microM), results in a rapid, reversible, time- and concentration-dependent disappearance of vinculin staining in adhesion plaques; actin-containing stress fibers also become disrupted following exposure of cells to PDGF. Disappearance of vinculin staining from adhesion plaques is also caused by 12-O-tetradecanoyl-phorbol-13-acetate (TPA; 200-400 nM), though the time course of the disappearance of vinculin staining under these conditions takes longer than in cells exposed to PDGF. The PDGF-induced removal of vinculin from adhesion plaques was inhibited in a concentration-dependent fashion by 8-(N,N-diethylamino) octyl-3,4,5-trimethoxybenzoate (TMB-8; 0.25-4 microM) and leupepetin (2-300 microM), and by n-alpha-tosyl-L-lysine chloromethylketone (TLCK; 100 microM) and trifluoperazine (TFP; 2.5 microM). Addition of PDGF to vascular smooth muscle cells caused a rapid, transient increase in cytosolic free calcium, from a basal resting level of 146 +/- 6.9 nM (SEM, n = 62) to 414 +/- 34 nM (SEM, n = 22) as determined using the calcium-sensitive indicator Fura-2 and Digitized Video Microscopy. This increase in cellular calcium preceded the disappearance of vinculin from adhesion plaques and was partially blocked by pretreatment of cells with TMB-8 but not leupeptin. This rise in cytosolic free calcium was found to occur in approximately 80% of the sample population and displayed both spatial and temporal subcellular heterogeneity. Exposure of cells to TPA (100 nM) did not result in a change in cytosolic free calcium. Both PDGF (20 ng/ml) and TPA (100 nM) caused cytosolic alkalinization which occurred after PDGF-induced disruption of vinculin from adhesion plaques, as determined using the pH-sensitive indicator BCECF and Digitized Video Microscopy. PDGF stimulated DNA synthesis and vinculin disruption in a similar dose-dependent fashion. Both could be inhibited by leupeptin or TMB-8. These results suggest that 1) exposure of vascular smooth muscle cells to PDGF is associated with the disruption of vinculin from adhesion plaques, 2) PDGF-induced vinculin disruption is regulated by an increase in cytosolic calcium (but not cytosolic alkalinization), and involves proteolysis; 3) activation of protein kinase C also causes vinculin removal from adhesion plaques but by a calcium-independent mechanism, and 4) the cellular response to PDGF-stimulated increases in cytosolic free calcium is heterogeneous.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Platelet-derived growth factor-induced alterations in vinculin distribution in porcine vascular smooth muscle cells. 312 Nov 90

Brief starvation is accompanied by decreased circulating levels of most amino acids, which has been attributed to an increased splanchnic uptake of amino acids, primarily alanine, for gluconeogenesis. However, quantitative data on splanchnic exchange of amino acids and gluconeogenic precursors is lacking. Consequently, arterial concentrations and splanchnic exchange of whole blood amino acids, ketone bodies, glucose, and gluconeogenic precursors were measured in 16 prolonged fasted (60 to 64 hours) and 15 overnight fasted (12 to 14 hours) healthy, nonobese subjects. After the 60-hour fast net splanchnic glucose production decreased by 41% to 0.31 +/- 0.02 mumol/L (P less than .001), whereas the splanchnic uptake of gluconeogenic precursors increased and could account for the total glucose output. Net splanchnic uptake of taurine, threonine, serine, glycine, lysine, histidine, and arginine rose significantly in response to fasting (P less than .05 to .01) due to increased splanchnic fractional extraction. Although the splanchnic fractional extraction of alanine was augmented by 40% (P less than .001), net splanchnic uptake was not influenced by fasting. Total net splanchnic uptake of amino acids increased by 68%, from 231 +/- 44 mumol/min in the postabsorptive state to 388 +/- 63 mumol/min (mean +/- SEM) (P less than .05) in the 60-hour fasted state. However, only one half of this rise was accounted for by gluconeogenic amino acids.
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PMID:Splanchnic metabolism of amino acids in healthy subjects: effect of 60 hours of fasting. 319 1

Cerebrospinal fluid (CSF) histidine concentration was significantly elevated in seven patients early in the alcohol withdrawal syndrome (206.3 +/- 74.4 (SEM) nanomols/ml CSF). When these same patients were restudied an average of six days later when alcohol withdrawal was clinically resolved, their mean CSF histidine concentration continued to be significantly elevated (164.7 +/- 24.7) when compared to normal (12.0 +/- 0.5 nanomols/ml CSF). Other amino acids (aspartic acid, serine, alanine, methionine, leucine, tyrosine, phenylalanine, lysine and arginine) showed no definite changes from normal, and no change during the course of alcohol withdrawal. Possible reasons for these high concentrations and the extreme variability (especially early in alcohol withdrawal) are discussed.
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PMID:Elevated cerebrospinal fluid histidine in alcohol withdrawal. 322 84


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