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)

This study determined the difference in rate of degradation between pure polymers of lactic acid (pla), glycolic acid (PGA), and various ratios of copolymers of these two substances. Fast-cured and slow-cured polyglycolide was compared with copolymers of glycolide/lactide intermixed in ratios of 75:25, 50:50, and 25:75, as well as pure polylactide. A total of 420 rats were implanted with carbon-14 and tritium-labeled polymers in bone and soft tissue. At intervals of 1, 2, 3, 5, 7, 9, and 11 months, groups of five animals with the implants in bone and five with the implants in the abdominal wall were sacrificed. The implant area as well as tissue from the liver, spleen, kidney, lung and some muscle tissue was analyzed for radioactivity along with the urine and feces collected throughout the experiment. Half-lives of the different polymers and copolymers were calculated from the radioactivity present in the implant area for each time interval. Half-life of the polymers and copolymers decreased from 5 months for 100% PGA to 1 week with 50:50 PGA:PLA copolymer and rapidly increased to 6.1 months for 100% PLA. Fast-cured PGA had a half-life in tissue of 0.85 months. No difference in rate of degradation was seen in soft tissue or bone. No significant radioactivity was detected in urine, feces, or tissue samples. From this study, it is concluded that control of degradation rate of the implant could best be attained by varying the composition of PLA and PGA between 75% and 100% PLA along with a corresponding 25% to 0% PGA. This would provide a half-life range of the implant of from 2 weeks to 6 months.
J Biomed Mater Res 1977 Sep
PMID:Degradation rates of oral resorbable implants (polylactates and polyglycolates): rate modification with changes in PLA/PGA copolymer ratios. 89 90

A highly sensitive radioimmunoassay for the measurement of plasma prostaglandins A and B, expressed in equivalents of PGA1, is described. This method was used for the measurement of prostaglandins A and B (PGA/B) in 23 healthy volunteers and 25 hypertensive patients. The PGA/B concentration in peripheral venous plasma of 23 healthy normotensive subjects is 115 +/- 15 pg/ml. The repeated measurement of the same plasma samples kept frozen for 60 days at -20 degrees C shows mean 194% increase of PGA/B concentration. The major site of synthesis of PGA/B seems to be the kidney. However in two patients PGA/B concentration in arterial blood was greater than in venous blood suggesting the possibility of cardio-pulmonary synthesis. The major site of inactivation is the hepatic circulation, as PGA/B concentration in hepatal venous blood is by 30% lower than in vena caval blood. The arterial concentration is 3% lower than venous PGA/B demonstrating very low pulmonary inactivation. Therefore the prostaglandins of the A and B series may represent a "circulating hormone". The plasmatic PGA/B is significantly increased in reno-vascular and essential hypertension.
Prostaglandins 1976 Sep
PMID:Radioimmunoassay of prostaglandins A and B in human blood. 96 52

1 The effect of isoprenaline on gastric secretion evoked by various means has been studied in conscious rats provided with Pavlov and Heidenhain pouches. 2 Interdigestive acid secretion in the Pavlov pouch was reduced by isoprenaline, whereas pepsin secretion was unaltered. 3 Central vagal stimulation effected by 2-deoxy-D-glucose injection evoked a gastric secretory response that was substantially reduced by isoprenaline. 4 2-Deoxy-D-glucose increased the mobilization of gastric mucosal histamine, an effect that was prevented by isoprenaline. 5 Isoprenaline infusion alone induced a slight increase in histamine mobilization and also a considerable elevation of immunoreactive serum gastrin concentration. 6 The secretory response to food in the Pavlov pouch was almost abolished by isoprenaline. 7 Although the acid response to histamine in the Heidenhain pouch was susceptible to isoprenaline inhibition, that to methacholine was not. 8 Pepsin secretion in the Heidenhain pouch preparation stimulated by histamine or methacholine seemed to be enhanced by isoprenaline.
Br J Pharmacol 1976 Sep
PMID:Further studies on the mode of action of isoprenaline on gastric secretion in the conscious rat. 97 74

The secretory response to 16, 16-dimethyl prostaglandin E2 (DMPG) administered orally in 4 different dosages and to placebo was evaluated in healthy volunteers over a 2-hr period. During stimulation of gastric secretion by histamine, DMPG at the highest dosage (1.5 mug per kg) reduced volume by 47% and acid output by 79%. Pepsin concentration was not affected. At the same dose, DMPG inhibited basal secretion by 54% and 99% for volume and acid output, respectively. There were no side effects secondary to DMPG administration, which indicates that this compound may be useful in treating peptic ulcer disease.
Gastroenterology 1975 Sep
PMID:Effects of an orally administered prostaglandin analogue (16, 16-dimethyl prostaglandin E2) on human gastric secretion. 115 77

Anchorin CII is a collagen binding protein of the annexin family associated with plasma membranes of chondrocytes, osteoblasts, and many other cells. As a major constituent of cartilage-derived matrix vesicles it has been shown to bind to native type II and X collagen. In accordance with this observation, here we show the localization of anchorin CII in the extracellular matrix of calcifying cartilage in the fetal human growth plate, and that it was restricted to the chondrocyte surface in proliferating and resting cartilage. Furthermore, we present evidence, using a slot blot assay, that anchorin CII not only binds to native type II and X collagen, but also to chondrocalcin, the carboxy-terminal extension of type II procollagen, in a calcium-independent manner. Pepsin digestion of type II collagen results in loss of anchorin CII binding, confirming our previous notion that the telopeptide region of type II collagen carries anchorin CII binding sites.
FEBS Lett 1992 Sep 28
PMID:Selective binding of anchorin CII (annexin V) to type II and X collagen and to chondrocalcin (C-propeptide of type II collagen). Implications for anchoring function between matrix vesicles and matrix proteins. 139 63

Blood flow in the left gastric artery was measured with an electromagnetic flowmeter in nine conscious beagle dogs. In the fasting state gastric motility and secretion exhibited periodical changes with an average cycle interval of 115.4 +/- 9.7 min. During a quiescent period, when gastric motility and secretion were minimal, the mean blood flow was stable at 33.9 +/- 3.8 ml/min. During the contracting phase each peristaltic contraction was coupled with a rapid fall and rise in blood flow (from 10.5 +/- 1.9 ml/min below to 21.2 +/- 3.8 ml/min above the precontraction levels) in 20-30 s. In addition there was a sustained elevation in blood flow (58.6 +/- 6.4 ml/min at the peak) lasting for 29.1 +/- 2.8 min. The onset of sustained blood flow elevation was preceded by that of motility in 63% of the cycles. In 23% of the cycles blood flow started to rise before the contracting phase began. Pepsin peaks coincided with blood flow peaks in two dogs and preceded the latter in the others. Feeding abolished periodic increases in motility and blood flow. It is concluded that left gastric arterial blood flow is not steady but exhibits dynamic changes in phase with periodic motor and secretory activities of the stomach in fasting conscious dogs.
Exp Physiol 1992 Sep
PMID:Interdigestive gastric blood flow: the relation to motor and secretory activities in conscious dogs. 141 53

According to the comparison of amino acid sequence between PGA (Penicillin G Acylase) and PBPs (Penicillin Binding Protein), We suggest that No. 565-595 peptide fragment in beta-subunit of PGA may be a substrate-binding site of enzyme. Plasmid pTZGA was constructed by cloning the 2.6 kb PGA gene of pWGA into phagemid pTZ18U The technique of site-specific mutagenesis was used to study the role of residue No. 579 (Ser) and No. 580 (Arg) of PGA. Four kinds of mutants were obtained (Ser579-->Gly579, Arg580-->Gly580, Arg580-->Glu580, Arg580-->Lys580), both Glu580 and Gly580 mutants showed no activity of enzyme and Lys580 mutant remained 30% and Gly579 mutant kept 70% activity of wilde type. The same protein expression of four mutants according to the results of ELISA indicate that mutation does not affect the expression of PGA, but Arg580 residue may be essential for substrate-binding or catalysis of PGA.
Shi Yan Sheng Wu Xue Bao 1992 Sep
PMID:[Studies on the function of Ser579 and Arg580 in beta-subunit of penicillin G acylase with the method of site-specific mutagenesis]. 147 18

The enzyme rhodanese is greatly stabilized in the range pH 4-6, and samples at pH 5 are fully active after several days at 23 degrees C. This is very different from results at pH greater than 7, where there is significant loss of activity within 1 h. A pH-dependent conformational change occurs below pH 4 in a transition centered around pH 3.25 that leads slowly to inactive rhodanese at pH 3 (t 1/2 = 22 min at pH3). The inactive rhodanese can be reactivated by incubation under conditions required for detergent-assisted refolding of denatured rhodanese. The inactive enzyme at pH 3 has the maximum of its intrinsic fluorescence spectrum shifted to 345 nm from 335 nm, which is characteristic of native rhodanese at pH greater than 4. At pH 3, rhodanese shows increased exposure of organized hydrophobic surfaces as measured by 1,1'-bis(4-anilino)naphthalene-5,5'-disulfonic acid binding. The secondary structure is maintained over the entire pH range studied (pH 2-7). Fluorescence anisotropy measurements of the intrinsic fluorescence provide evidence suggesting that the pH transition produces a state that does not display greatly increased average flexibility at tryptophan residues. Pepsin digestibility of rhodanese follows the pH dependence of conformational changes reported by activity and physical methods. Rhodanese is resistant to proteolysis above pH 4 but becomes increasingly susceptible as the pH is lowered. The form of the enzyme at pH 3 is cleaved at discrete sites to produce a few large fragments. It appears that pepsin initially cleaves close to one end of the protein and then clips at additional sites to produce species of a size expected for the individual domains into which rhodanese is folded. Overall, it appears that in the pH range between pH 3 and 4, titration of groups on rhodanese leads to opening of the structure to produce a conformation resembling, but more rigid than, the molten globule state that is observed as an intermediate during reversible unfolding of rhodanese.
J Biol Chem 1992 Sep 25
PMID:Acid pH-induced conformational changes in bovine liver rhodanese. 152 67

Flow cytometric DNA analysis of nuclear suspensions from formalin-fixed, paraffin-embedded tissue often fails to detect aneuploid cell populations present in corresponding fresh tissue. Nuclear suspensions were prepared by 8 different modifications and standard Hedley's method using 50-microns sections of tissue blocks from 8 breast and 8 colonic carcinomas, all previously known to be DNA aneuploid by analysis of fresh tumor. Pepsin solutions of three different enzymatic activities were used to release nuclei using three different tissue digest formats. DNA aneuploidy was demonstrated overall in 7 of 72 different colon tumor experiments and 25 of 72 breast cancer experiments. Modifications yielded aneuploid populations not detected by the standard Hedley method; DNA aneuploidy of 4 breast and 2 colon cancers was detected by modifications compared to 2 breast and 1 colon cancer demonstrated by the standard. No single method consistently demonstrated DNA aneuploidy. High histogram baselines, presumably from debris, contributed to the marked loss of sensitivity in detecting most DNA aneuploid populations. Detection of DNA aneuploidy was most closely associated with specific cases, regardless of the method of nuclear suspension preparation. Recovery of DNA aneuploid nuclei seems to depend primarily on tissue processing or innate characteristics of the tumor cells, not on the method used to prepare the nuclear suspension.
Am J Clin Pathol 1992 Sep
PMID:Comparison of eight modifications of Hedley's method for flow cytometric DNA ploidy analysis of paraffin-embedded tissue. 152 60

Earlier studies from this laboratory revealed that killer lymphocyte lineages are inactivated in the tumor-bearing host by macrophage-derived PGE2. In this study, we examined whether tumor bearing causes a change in the density or affinity of PGE2 receptors on lymphocytes, making them more vulnerable to PGE2 action, and whether it enhances PGE2 production by host macrophages. PGE2 receptors were examined on both unfractionated and monocyte-macrophage-depleted splenocytes of normal or tumor-bearing C3H/HeJ mice (at 25 days following s.c. transplantation of 10(6) C3 mammary adenocarcinoma cells) using a [3H]PGE2 binding assay in the presence of increasing (up to 10(4)-fold) concentrations of unlabeled PGE2 (or PGA or PGF2 alpha as specificity controls) followed by a Scatchard analysis. PGE2 production by splenic macrophages was measured with a radio-immunoassay. Results revealed that splenocytes in normal and tumor-bearing mice bear specific receptors for PGE2, since splenocyte binding of [3H]PGE2 (10(-9) M) was inhibited in the presence of excess unlabeled PGE2, but not 10(-4)-fold excess PGA or PGF2 alpha. Tumor-bearing did not appear to cause an appreciable change in the affinity or density of these receptors, since Kd and Bmax values for PGE2 binding were similar for normal and tumor-bearing mice. However, specific PGE2-binding by splenocytes in vitro was reduced in tumor-bearing mice. Three types of evidence indicate that this resulted from a partial occupation of PGE2 receptors on lymphocytes with PGE2 produced by splenic macrophages of tumor-bearing hosts. First, depletion of monocyte-macrophages from the splenocyte population improved this binding in tumor-bearing but not normal mice.(ABSTRACT TRUNCATED AT 250 WORDS)
Immunol Lett 1991 Sep
PMID:PGE2 receptors on murine splenic lymphocytes: effects of tumor bearing. 166 31


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