Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prostaglandins PGE-1 or PGA-1 (0.5 to 1 mug per min) were infused into the stenosed renal artery of anesthetized hypertensive dogs. Increased urine volume, sodium and potassium excretion, and p-aminohippurate clearance were found during the prostaglandin infusion period in the infused kidney as compared to the control periods before infusion. Creatinine clearance was increased during infusion of PGE-1. The noninfused, nonischemic kidney showed no effect at the time of infusion with PGE-1 but in the case of PGA-1, the p-aminohippurate and creatinine clearances and urine diuresis were decreased. As a result, the mean aortic blood pressure decreased. Both prostaglandins increased the renal vein renin in the infused kidney. PGA-1 did affect renin release of the noninfused kidney, but PGE-1, which is rapidly inactivated by the lung, did not have this effect. Renin release seems to be influenced by electrolyte diuresis operating through the macula densa mechanism. However, the lowering of blood pressure seen in this study cannot exclude the involvement of the stretch receptors (the juxtaglomerular cells) for renin release. The increased renin release after prostaglandin administration seems to be a protective renal mechanism against the drug-induced hypotension. It seems to be induced by the direct sodium and water diuretic effects of prostaglandins.
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PMID:Direct effect of prostaglandins in renal function and renin release in the presence of renal ischemia in the dog. 111 61

To understand more directly the tissue defect in osteogenesis imperfecta (OI), bone matrix was analyzed from an infant with lethal OI (type II) of defined mutation (collagen alpha 2(I)Gly580-->Asp). Pepsin-solubilized alpha 1(I) and alpha 2(I) chains and derived CNBr-peptides migrated more slowly on sodium dodecyl sulfate-polyacrylamide gel electrophoresis compared with normal human controls. The peptide alpha 2(I)CB3,5, predicted to contain the mutation site, ran as a retarded doublet band and was purified by high performance liquid chromatography and digested with V8 protease. Two peptides with amino-terminal sequences beginning at residue 576 of the alpha 2(I) chain were isolated. One had the normal sequence. The other differed in that aspartic acid replaced glycine at residue 580 as predicted from cDNA analysis, and in having an unhydroxylated proline at residue 579. From yields on microsequencing and the relative intensities of the two forms of alpha 2(I)CB3,5 on SDS-polyacrylamide gel electrophoresis, the ratio of mutant to normal alpha 2(I) chains in the infant's bone matrix was 0.7/1. Although the effects of an efficient incorporation of mutant chains on the properties of the bone matrix are unknown, it may be that in this OI case the tissue abnormalities result more from the presence of mutant protein than from an underexpression of matrix.
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PMID:Incorporation of type I collagen molecules that contain a mutant alpha 2(I) chain (Gly580-->Asp) into bone matrix in a lethal case of osteogenesis imperfecta. 138 13

The action of six different enzymes on the function and structure of Factor H was investigated by use of sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, haemagglutination, two enzyme-linked immunosorbent assay systems and an assay for Factor I cofactor activity. Six monoclonal antibodies directed against the 38 kDa tryptic fragment of Factor H [which contains the binding site for C3b (a 180 kDa fragment of the third component of complement) and the cofactor activity] were also used to detect cleavage products derived from the same fragment. Elastase, chymotrypsin A4 or trypsin first cleaved Factor H to 36-38 kDa fragments carrying all six monoclonal anti-(Factor H)-binding sites. In parallel, the interaction of Factor H with surface-bound C3b was lost, whereas the cofactor function was preserved. Further cleavage of the 36-38 kDa fragments into two 13-19 kDa fragments (one carrying the MAH4 and MRC OX 24 epitopes, the other the MAH1, MAH2, MAH3 and MRC OX 23 epitopes) destroyed cofactor activity. Pepsin, bromelain or papain rapidly split off a 13-15 kDa fragment of Factor H carrying the MAH1, MAH2, MAH3 and MRC OX 23 epitopes and destroyed all tested functions of Factor H. Ficin cleaved Factor H into disulphide-linked fragments smaller than 25 kDa, but did not affect the functions of the Factor H molecule. The 38 kDa tryptic fragment of Factor H is the N-terminal end of the Factor H molecule, as determined by N-terminal sequence analysis. A model is presented of the substructure of Factor H.
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PMID:Structural and functional analysis of the complement component factor H with the use of different enzymes and monoclonal antibodies to factor H. 293 33

The proteins of the cuticle of adult Ascaris lumbricoides suum were characterized with respect to heterogeneity, glycosylation, and susceptibility to collagenase. Pepsin digestion of intact cuticles was used to determine the extent of stable triple-helical structures of the cuticular components. With sodium dodecyl sulfate-poly-acrylamide gel electrophoresis, it was shown that treatment of purified cuticles with beta-mercaptoethanol released three components (99, 90, and 68 kDa) which comprise 95% of the total solubilized material. The remaining fraction consists of at least four components (16, 28, 154, and 173 kDa). Periodic acid-Schiff staining showed that the only glycoprotein was the 173-kDa component. All cuticular components, except the 173-kDa protein, were degraded by bacterial collagenase. Pepsin digestion of intact cuticles for 24 hr at 4 C produced, after reduction, a 95-kDa fragment; by 96 hr, four fragments (95, 90, 83, and 77 kDa) were evident. When the 96-hr pepsin digest was treated with fresh pepsin, the 77-kDa fragment became the major constituent. With agarose gel electrophoresis, analysis of non-reduced, pepsin-released material revealed intact aggregates that were greater than 2 X 10(3) kDa. The enzyme digestion studies indicate that, with the exception of the 173-kDa component, each cuticular protein contains collagenous domains and that, within the cuticle, the longest contiguous collagen chain in a triple-helical conformation has a uniform molecular size of 77 kDa.
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PMID:Ascaris lumbricoides: characterization of the collagenous components of the adult cuticle. 298 39

Pepsin-solubilized bovine dermal collagen was reconstituted in 0.02 M sodium phosphate (pH 7.2), concentrated to 30-40 mg/ml, and adjusted to physiological ionic strength by addition of sodium chloride. These preparations, at 4-15 degrees C, are fibrillar suspensions composed of fibrils of varying diameters and nonassociated molecules. Addition of heparin to these suspensions promoted a dose-dependent increase in average fibril diameter as measured by turbidimetry and electron microscopic analyses. These effects were relatively specific for heparin and heparin-like glycosaminoglycans. Chondroitin sulfate and hyaluronic acid had little or no effect on fibrillar diameters under these conditions, whereas dermatan sulfate had an intermediate effect on fibrillar reorganization. Differential scanning calorimetry revealed that addition of optimal concentrations of heparin generated fibrils of higher stability and that this effect was associated with the disappearance of structures of lower stability, including nonassociated molecules and thin fibrils. Light microscopic analyses of the fibrillar collagen/heparin matrix showed it to be a more open network of distinct collagen fibers than was observed with the fibrillar collagen preparation alone. Binding experiments indicated that heparin bound to fibrillar collagen in a saturable fashion with a Kd of approximately 4 X 10(-7) M. Creep experiments provided evidence that the addition of heparin to fibrillar collagen suspensions greatly reduces the gelation phenomenon that is normally observed when such suspensions are warmed to 37 degrees C. These differences in fibrillar architecture may be in part responsible for differences noted in the biological response to fibrillar collagen and fibrillar collagen/heparin implants in vivo (McPherson et al., 1988).
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PMID:The effects of heparin on the physicochemical properties of reconstituted collagen. 312 21

Extraction, fractionation and characterization by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of proteins from Carioca 80 beans (Phaseolus vulgaris) were performed at three pH values (2.5, 8.0 and 9.0). Extraction at pH 7.0 proved to be more efficient and, after dialysis, produced a better separation of the albumin and globulin fractions. Relative mobility of the main protein in the globulin fractions occurred between 0.30 and 0.40, and dissociation was observed when the pH was increased. The two most representative bands gave molecular weights of 35,400 and 76,900, while in regard to the trypsin inhibitor, three bands gave 28,800, 22,500 and 18,300. Pepsin and pancreatin in vitro digestibility rendered values of 33.43% and 62.63% for whole flour and for protein precipitated at pH 4.5, respectively. The content of available methionine found, of 1.36 g/16 g N, appears to be high in relation to that of other bean varieties.
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PMID:[Extraction, partial characterization and nutritional aspects of proteins from Carioca 80 bean (Phaseolus vulgaris L.)]. 345 22

In the presence of anti-insulin antibody, 2-to 3-fold enhancement of 125I-insulin binding to liver membranes was observed when binding was estimated by the radioactivity of 125I-insulin bound to the membrane pellets. However, after 125I-insulin was covalently cross-linked to liver membranes using disuccinimidyl suberate in the presence of anti-insulin antibody, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography showed that 125I-insulin bound to the alpha-subunit of the insulin receptor was inhibited by anti-insulin insulin antibody in an dose-dependent manner. More importantly, at an anti-insulin antibody dilution range between 1:50 and 1:5,000, sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two 125I-labelled bands of mol wt 62,000 and 27,000, while only one band of mol wt 130,000 was revealed in the absence of anti-insulin antibody. These Mr = 62,000 and Mr = 27,000 bands were found to be the heavy and the light chain of anti-insulin IgG molecules respectively. Pepsin digested anti-insulin serum had only an inhibitory effect on 125I-insulin binding to liver membranes. Non-immunized guinea pig serum or IgG completely abolished the enhanced effect of anti-insulin antibody. Further, this enhanced effect was inhibited by Fc fragment-specific anti-IgG serum or H&L-chain-specific anti-IgG serum in a dose-dependent manner. Protein A also inhibited the effect of anti-insulin antibody. In IM-9 lymphocytes and human red blood cell ghosts, which have no Fc gamma receptors, enhancement of insulin binding was not observed in the presence of anti-insulin antibody.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of anti-insulin antibody on insulin binding to liver membranes: evidence against antibody-induced enhancement of insulin binding to the insulin receptor. 352 44

1. For a few weeks, immediately post-natally, the abomasum of the ruminant stomach can be regarded as the analogue of the simple stomach for at this time food passes directly to the abomasum because of closure of the oesophageal groove.2. Using standard fractional and serial test meal techniques discussed by Hunt (1956) and adapted for use in the calf, abomasal emptying, acid and pepsin secretion have been examined. Phenol red was used as a marker to measure volume changes of the test meal.3. Abomasal emptying is exponential in character whether large or small volumes of fluid are instilled into the abomasum. The initial and end phase of emptying shows variable rates between animals.4. Glucose and lactose solutions inhibit abomasal emptying as well as acid production.5. Sodium chloride and sodium bicarbonate of low concentration, near isotonic with blood plasma, stimulate abomasal emptying but the bicarbonate is most effective. Hypertonic solutions of these salts inhibit abomasal emptying.6. Pepsin secretion in the abomasum of the calf is not affected by test meals of glucose, lactose, sodium chloride or sodium bicarbonate.7. These results shows a great similarity between the physiology of the abomasum of the milk-fed calf and the simple stomach. This suggests that the same duodenal receptors, discussed by Hunt & Knox (1968), which control gastric movement in man are also effective in controlling gastric emptying in the milk-fed calf.
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PMID:Gastric emptying and secretion in the milk-fed calf. 456 10

1. The abomasum of the milk-fed calf has been examined using an adaptation of the Serial Test Meal method devised by Hunt & Spurrell (1951). The emptying process, acid secretion and pepsin secretion were studied.2. Using serial test meals of simple solutions instilled into the abomasum via a cannula, our investigation leaves no doubt that the osmolarity of the abomasal contents significantly modifies the rate of abomasal emptying.3. Hypotonic and isotonic solutions of sodium chloride and sodium bicarbonate increase abomasal emptying but bicarbonate is most effective.4. Increasing the concentration of solutes in the abomasal contents slows abomasal emptying. Sodium chloride, sodium bicarbonate, ammonium chloride and urea do not delay abomasal emptying until hypertonic concentrations are attained. Hypotonic solutions of potassium chloride, calcium chloride, glucose, lactose, hydrochloric acid and acetic acid delay abomasal emptying.5. The results obtained in the calf show that the abomasum is under restraint probably from duodenal receptors as is the simple stomach (Hunt & Knox, 1968) and that an osmoreceptor as postulated by Hunt (1956) is an important factor in this mechanism.6. Acid secretion is inhibited when hypertonic solutions are instilled into the abomasum.7. Pepsin secretion is not affected by simple solutions in the abomasum.8. Gastric function in the milk-fed calf appears to be controlled by mechanisms essentially similar to those already demonstrated in the simple stomach.
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PMID:The effect of some molecules and ions on gastric function in the milk-fed calf. 456 11

Gastric secretion in man is inhibited by the presence in the duodenum of hyperosmolar and hypoosmolar solutions. Both acid and pepsin outputs are affected. There is no change in hydrogen, sodium, or potassium ion concentration in the gastric juice. Pepsin concentration, however, is reduced by all inhibitory stimuli. Inhibition is thought to act directly upon parietal and chief cells, and a possible basis for this mechanism is discussed. The response is similar in control subjects and duodenal ulcer patients; there is in particular no evidence of impaired inhibition in the ulcer group. An anomalous feature is the relatively small inhibition of acid output after hypertonic saline in control subjects compared with the duodenal ulcer patients.
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PMID:Duodenal inhibition of gastric secretion by osmotic agents in normal subjects and patients with duodenal ulcer. 490 22


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