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)

1. The serum gastrin level, gastric mucosal blood flow and acid secretion from the canine Heidenhain pouch have been measured in response to the introduction of bovine serum albumin, pepsin-digested albumin, an amino acid mixture, liver extract and mannitol used as control. 2. Distention of the Heidenhain pouch with mannitol or albumnin at pH 5-0 produced a similar pressure-related increase of acid secretion reaching a peak of only 10 percent of the maximal response to histamine. Pepsin-digested albumin was capable of producing larger acid outputs than undigested albumin. The highest acid output, attaining about 80 percent of the maximal response to histamine, was obtained with liver extract both before and after exhaustive dialysis to remove all the amino acids and short peptide fragments. An amino acid mixture containing all essential amino acids was also found to stimulate acid secretion but a lesser degree than liver extract. 3. This concluded that it is not the intact protein but the products of its digestion, the polypeptides and free amino acids, which are potent chemical stimulants of acid secretion from the oxyntic gland area. Since the serum gastrin level was not changed during acid secretion induced by peptic digests bathing the oxyntic gland area, the mechanism of chemical stimulation appears to be gastrin-independent. 4. The response to chemical stimulation by peptic digests can be greatly potentiated by combining this with distention of the oxyntic gland area. Topical application of xylocaine or atropine causes a marked decrease of Heidenhain pouch response to peptic digests, suggesting a possible neural reflex component in the mechanism of chemical stimulation of the oxyntic gland area. 5. When the pH of the liver extract in the Heidenhain pouch was gradually decreased in sequential order from 5-0 to 1-0, this resulted in a pH-related decrease in acid secretion and in the mucosal blood flow falling to the basal level at pH 1-0. Exogenous secretion given in graded doses from 0-5 to 8-0 u./kg. hr caused a small but dose-related inhibition of acid response to liver extract accompanied by a decrease of mucosal blood flow but without any significant change in the serum gastrin level. 6. The results indicate that the chemical stimulation of the oxyntic gland area by peptic digests is capable of inducing acid secretion by a local, gastrin-independent, partially neural reflex mechanism; sensitive to pH, pressure and secretin.
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PMID:Chemical stimulatory mechanism in gastric secretion. 23 20

Albumin magnetic microparticles reversibly adsorb thyroxine. They quickly establish equilibrium allowing time and temperature independent measurements in T4 radioassays. We used these particles to compare the efficiency of NaOH, HCl, pepsin, sodium trichloroacetate, and 8-anilino-1-naphthalene sulfonic acid to release 125I-T4 from serum, T4-free serum and human serum albumin. We found that the efficiency of the reagents to extract 125I-T4 depended on the concentration and type of proteins to which the labelled hormone was bound. Pepsin was the most effective reagent and we utilized it for a T4 radioimmunoassay, in which albumin magnetic microparticles were used to separate free from bound hormone. We also utilized the particles in a T4 non-immune radioassay. Both assays accurately measured total serum T4, however the radioimmunoassay was simpler, less dependent on protein content of serum, required a smaller serum sample and provided slightly higher T4 values. We describe a magnetic rack which allows simultaneous handling of fifty individual tubes with an intra-assay C.V. of 2.1% for the radioimmunoassay and 2.3% for the non-immune assay and an inter-assay C.V. of 3.1%, respectively.
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PMID:Immune and non-immune T4 radioassays utilizing albumin magnetic microparticles. 63 18

The binding of tritiated prostaglandins (PGA1, PGE1, PGF2alpha, and PGE2) to human and bovine serum albumins was studied by equilibrium dialysis and batchwise gel equilibration with Sephadex G-25. During equilibrium dialysis (36 hours, 4 degrees C), about half of the PGEs, but not PGA and PGF2alpha, were transformed into dehydration products; by contrast, equilibration of the prostaglandins was attained in less than a half-hour by the batchwise use of Sephadex G-25 at 25 degrees C, with no detectable ligand instability. The values of the apparent association constants for albumin-prostaglandin interactions were inversely related to the protein concentration in the assay systems. "True" apparent association constants (NKo) were measured by extrapolation to zero protein concentration. The NKo values were estimated to be 9.4 X 10(4), 2.7 X 10(4), 9 X 10(3) and 6 X 10(3) M-1 for the interaction of human serum albumin with PGA1, PGE1, PGF2alpha and PGE2, respectively. Very similar values were found for the corresponding bovine serum albumin-Prostaglandin interactions. When comparable, the data obtained by both methods were in excellent agreement. Our results were also in agreement with published values for PGA1 and PGF2alpha, both of which are relatively stable in neutral aqueous phase. Batchwise gel equilibration appears to be a useful method, if thermodynamically valid data are desired in the presence of possible ligand and/or "receptor" instability. We conclude that albumin binding probably affords circulating PGA1 a modest protection from its clearance mechanisms.
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PMID:Prostaglandin-macromolecule interactions. I. Noncovalent binding of prostaglandins A1, E1, F2alpha, and E2 by human and bovine serum albumins. 94 73

The present studies were undertaken to characterize the affinity of CMV-induced Fc receptors for each of the subclasses of human IgG and to define the specific region of the IgG Fc fragment interacting with such receptors. To do this, we infected confluent human embryonic lung (HEL) cell monolayers with CMV (strain AD169) and then used a double radiolabel assay to measure adherence of antibody-coated E. coli 06 to such monolayers. Preincubating monolayers with each of the 4 subclasses of human IgG (but not IgA, IgM, or human or bovine albumin) abrogated the enhancing effect of CMV infection on adherence of antibody-coated E. coli 06 to HEL monolayers. Pepsin-derived, purified Fc fragments of human IgG had a similar abrogative effect. Preincubating these with staphylococcal protein A did not reduce their capacity to interfere with binding of antibody-coated E. coli to CMV-induced Fc receptors. These observations establish a broad range of immunoreactivity for CMV-induced Fc receptors, that encompasses all 4 subclasses of human IgG. They also provide indirect evidence that the reaction site of CMV-induced Fc receptors is in the CH2 domain of the Fc fragment.
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PMID:Immunoreactivity of cytomegalovirus-induced Fc receptors. 282 62

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

The effects of intravenous administration of pepsin on autologous immune complex glomerulonephritis, which is an established experimental model of membranous glomerulopathy in human, were investigated. Sensitization of rats with renal tubular antigen induced an increase in urinary protein excretion, decreases in serum levels of total protein, albumin and immunoglobulin G and histopathological abnormalities in glomerulus. A significant increase in serum immune complex and glomerular immune complex deposit were also observed. These abnormalities were ameliorated by pepsin. Pepsin may be effective and beneficial in the treatment of immune complex nephritis.
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PMID:The effect of pepsin on autologous immune complex glomerulonephritis. 622 64

Pepsin (3.6 nmol) was detected by the following three-step procedure: (i) reaction with a 20-fold molar excess of BO-IMI (a fluorophore containing a reactive imidazole group) in the presence of a 150-fold molar excess of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and 2% sodium dodecyl sulfate; (ii) gel filtration (spin column) to remove most of the residual BO-IMI; and (iii) capillary electrophoresis with laser-induced fluorescence detection. For the latter step, 8.5 x 10(-7) of the original sample was injected. BO-IMI/EDC targets phosphomonoesters and does not label albumin (prior knowledge). Progressive dephosphorylation of pepsin with acid phosphatase reduced its labeling with BO-IMI. Thus, the BO-IMI, as intended, labels the phosphate group on pepsin. Such BO-IMI labeling should be useful in general for studying phosphoproteins and phosphopeptides.
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PMID:Phosphate-specific fluorescence labeling of pepsin by BO-IMI. 750 26

Pepsin-solubilized collagen VI in triple-helical and heat-denatured, unfolded form was shown to promote Mg(2+)- and Mn(2+)-dependent attachment and spreading of various cell lines. On the triple-helical substrate no inhibition of cell adhesion was observed with several synthetic RGD peptides except in the case of A375 melanoma cells. In contrast, adhesion to the unfolded substrate was highly sensitive to RGD inhibition. Nine synthetic peptides were designed according to 10 RGD sequences present in the triple-helical sequence of human collagen alpha 1(VI), alpha 2(VI), and alpha 3(VI) chains. Only one peptide, corresponding to the C-terminal end of alpha 3(VI) chain, showed substantial inhibitory activity, whereas several peptides were active in direct adhesion assays when used as albumin conjugates. Inhibition tests with antibodies to integrin subunits, affinity chromatography, and ligand binding with purified integrins (alpha 1 beta 1, alpha 2 beta 1, alpha V beta 3, and alpha IIb beta 3) were used to identify collagen VI receptors. Binding to the triple-helical substrate is mediated by alpha 1 beta 1 and alpha 2 beta 1 integrins. Binding of both integrins to collagen VI was weaker than that to collagens I and/or IV. Recognition of the denatured substrate is mediated by beta 1 and beta 3 integrins. Activity was shown for alpha 5 beta 1 and alpha V beta 3 and weakly for alpha IIb beta 3 but not all alpha subunits possibly involved were identified. Distinct sets of receptors were also involved in A375 cell binding to triple-helical (beta 1-mediated) and denatured (beta 3-mediated) collagen VI, even though in this case both interactions could be efficiently inhibited by RGD peptides.
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PMID:Integrin and Arg-Gly-Asp dependence of cell adhesion to the native and unfolded triple helix of collagen type VI. 838 21

Arterial hypertension-related renal damage is an increasingly common problem recently, because approximately 25% of patients currently treated with dialysis were hypertensive before renal replacement therapy was started. Hypertension is also known as a metabolic disease, while carbohydrate, purine and lipid disturbances are the features of this syndrome. On the other hand, the progression of renal disease depends on the extent of tubulointerstitial injury. For this reason, we undertook a study to evaluate the relationship between excretion of the markers of tubular damage (NAG) and some parameters of carbohydrate, purine and lipid metabolism in untreated essential hypertension. Both healthy volunteers (n = 15) aged 32. 6+/-7.8 and essential hypertensives (n = 25) aged 37.24+/-11.39 underwent the same tests. These tests were performed at 2-day intervals: intravenous glucose tolerance test with 0.5 g/kg b.w. as 40% glucose solution and oral fructose load test with 1.0 g/kg b.w. Area under glucose curve (GA) and serum uric acid post-fructose (PUAA) were calculated. Fasting: insulin, total cholesterol and LDL, triglycerides, free fatty acids (FFA) and urine excretion of NAG, albumin were determined. Glomerular filtration rate was estimated as creatinine clearance. Hypertensives showed statistically higher BMI (p<0.007), NAG (p<0.02), total cholesterol (p<0.01), LDL (p<0.007), FFA (p<0.007), insulin (p<0.01), PGA (p<0.01) and PUAA (p<0.03). NAG excretion correlated positively with WHR (r = 0.40), MAP (r = 0.47) and PUAA (r = 0.47) in hypertensives only. We presume that tubular injury at an early stage of renal damage in patients with essential hypertension could be a part of metabolic syndrome X.
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PMID:Hypertensive nephropathy - an increasing clinical problem. 1020 62

Our laboratory has investigated hepatocyte transplantation using biodegradable polymer matrices as an alternative treatment to end-stage liver disease. One of the major limitations has been the insufficient survival of an adequate mass of transplanted cells. This study investigates a novel method of dynamic seeding and culture of hepatocytes in a flow perfusion system. In experiment I, hepatocytes were flow-seeded onto PGA scaffolds and cultured in a flow perfusion system for 24 h. Overall metabolic activity and distribution of cells were assessed by their ability to reduce MTT. DNA quantification was used to determine the number of cells attached. Culture medium was analyzed for albumin content. In Experiment II, hepatocyte/polymer constructs were cultured in a perfusion system for 2 and 7 days. The constructs were examined by SEM and histology. Culture medium was analyzed for albumin. In experiment I, an average of 4.4 X 10(6) cells attached to the scaffolds by DNA quantification. Cells maintained a high metabolic activity and secreted albumin at a rate of 13 pg/cell/day. In experiment II, SEM demonstrated successful attachment of hepatocytes on the scaffolds after 2 and 7 days. Cells appeared healthy on histology and maintained a high rate of albumin secretion through day 7. Hepatocytes can be dynamically seeded onto biodegradable polymers and survive with a high rate of albumin synthesis in the flow perfusion culture system.
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PMID:Dynamic seeding and in vitro culture of hepatocytes in a flow perfusion system. 1094 Nov 99


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