Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:001400 (PRP)
 1,320 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A synthetic iodopeptide having a glutamic acid-diiodotyrosine molar ratio of 1:1 has been shown to be an effective anticoagulant both in vivo and in vitro. Contrasted with heparin the following general conclusions may be made regarding its action. The iodopeptide does not act through the inactivation of thrombin in plasma. Iodopeptide does interact with fibrinogen to form a complex which, in vitro, is not soluble in buffered saline at physiological pH. At pH 8, iodopeptide interacts with fibrinogen to form a soluble complex in the presence of 0.9% NaCl that is not coaguable either by thrombin or Crotalus venom enzymes. All the available evidence indicates that the fibrinogen to fibrin conversion is not inhibited under these conditions, but that fibrin, once formed, is not able to polymerize due to interference by iodopeptide. Similar results were obtained with heparin in vitro with thrombin-fibrinogen mixtures in the absence of NaCl. Studies with Russell's viper venom in native PRP strongly suggest that the iodopeptide also interferes with processes in the early coagulation pathway associated with prothrombin activation.
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PMID:Studies on the action mechanism of the antihemostatic effect of lodopeptides. 0 4

Factors affecting the viability and function of stored platelet concentrates have been investigated in a blood component programme. It was found that platelets could be maintained for up to 72 h without bacterial contamination under the following conditions: (1) surgical skin preparation at venipuncture site; (2) blood collection in CPD or ACD anticoagulant in a closed bag system; (3) centrifugation of PRP at 3000 g for 20 min; (4) storage in Fenwal PL-146, Cutter CL-2383, or McGaw plastic bags; (5) resuspension of the platelet pellet in 70 ml residual plasma; (6) storage at 22+/-2 degrees C; and (7) constant gentle mixing throughout storage. Platelet viability as determined by recovery and survival is largely maintained, as is platelet function measured by template bleeding time. Both viability and function of concentrated platelets stored at 4 degrees C are severely compromised.
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PMID:Preparation and storage of platelet concentrates. II. Storage variables influencing platelet viability and function. 1 Sep 56

Effects of divalent cations on ADP-induced aggregation response were examined. Bovine platelets were transferred by Sepharose 2B gel filtration from citrate-PRP into citrate free buffer (buffer-GFP). Response increases, reaches a maximum and decreases with increasing calcium and/or magnesium concentration. For either calcium or magnesium alone, increasing response is proportional to a rate coefficient and, through an apparent ion-platelet association constant, to the fraction of platelet critical sites bound to cation. With both ions present, bound magnesium appears to inhibit bound calcium in excess of that accounted for by competition and a lower rate coefficient for bound magnesium. With citrate present in buffer-GFP, apparent association constants increase, excess magnesium inhibition is present, but systems are path dependent. Initial conditions appear to establish a response which is thereafter immutable to environmental magnesium alteration. Citrate-PRP resembles buffer-GFP: response is sensitive to the selective removal of calcium and excess magnesium inhibition is present. With heparin-PRP, response is immutable to the selective removal of approximately 90% of initial calcium. The dependency of response inhibition observed at high divalent cation concentrations indicates that aggregation is not due to interplatelet cross linking by ions. Ion effects are similar for bovine and human platelets.
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PMID:Effects of ions on ADP-induced aggregation of bovine or human platelets. 1 94

The ADP- and collagen-induced aggregation of platelets in PRP of healthy probands was tested in vitro in the presence of 4 heparin preparations (Novo, Vitrum, Liquemin, Haemoderivate) and of a heparinoid (Eleparon). None of the preparations caused a significant direct aggregation. The collagen-induced aggregation was inhibited by all mentioned preparations; thereby the heparins proved to be effective approx. to the same degree whereas the heparinoid proved to be significantly less effective. The ADP-induced aggregation was potentiated by all preparations. A considerably different sensitivity to heparin could be observed in the single PRP's. A special method was found out to exclude the influence of the heparin-sensitivity of the PRP's to compare the special effects of the heparins.
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PMID:[Influence of five commercial heparin preparations on the collagen induced platelet aggregation (author's transl)]. 7 75

Antisera raised in response to proline-rich proteins purified from parotid secretions of man and the primate Macaca fascicularis were employed to investigate the interrelationships of these proteins by immunodiffusion, immunoelectrophoresis and the combined use of disc gel acrylamide electrophoresis with radial immunodiffusion. The major human proline-rich proteins, PRP I, PRP II, PRP III and PRP IV as well as several minor proline-rich proteins cross-react with antiserum to PRP I or PRP III. Similarly primate parotid saliva contains several components cross-reacting with antiserum directed against a purified primate proline-rich protein, MPRP. Antiserum to PRP I or PRP III cross-reacted with MPRP and primate parotid saliva protein, whereas antiserum to MPRP cross-reacted only with human parotid saliva protein and not with the isolated human proline-rich proteins. The immunological relationships of these salivary proline-rich proteins within and between species suggest their origin from a common precursor molecule.
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PMID:Immunological comparison of proline-rich proteins from human and primate parotid secretion. 11 Mar 58

Inhibition of calcium phosphate precipitation in saliva, and prevention of the formation of mineral accretions on tooth surfaces, has been ascribed to the existence of inhibiting salivary macromolecules. Marked reductions in the crystal growth rate of hydroxyapatite (HA) seeds were measured in supersaturated solutions containing either of two proline-rich proteins, PRP1 or PRP3, or statherin; the three macromolecules were isolated from human parotid saliva. The reductions were also observed when the HA seeds were pretreated with solutions of the macromolecules before adding them to the supersaturated calcium phosphate solution. This effect was very similar in the case of the two PRPs and it was directly related to the extent of adsorption site coverage of these proteins on the HA seeds. The effect of statherin was larger than anticipated from its adsorption behavior. However, comparison on the basis of number of moles adsorbed per unit area of HA shows that the PRP are more effective inhibitors than statherin. The macromolecule concentrations used were considerably lower than those in the salivary secretions, therefore these macromolecules could readily prevent mineral accretion on tooth surfaces through their adsorption onto the enamel surface.
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PMID:Effect of human salivary proteins on the precipitation kinetics of calcium phosphate. 11 54

Rapid diagnosis of Haemophilus influenzae type b meningitis is possible using immunological tests for capsular antigen (polyribophosphate, PRP), such as countercurrent immunoelectrophoresis (CIE) and latex particle agglutination (LPA). We compared two tests in monkeys with evolving, serially quantitated H. influenzae type b bacteremia (n = 23) and meningitis (n = 21). In vitro, the LPA test was sensitive to 0.5 ng of PRP/ml of saline, and the CIE test was sensitive to 1.0 ng/ml; in serum, however, CIE detected 5.0 ng of PRP/ml, whereas the sensitivity of LPA was unchanged. LPA detected PRP earlier in the course of bacteremia (mean, 12 h after onset; range, 4 to 36 h) than did CIE (mean, 45 h; range, 4 to 168 h) (P less than 0.01). A positive LPA test required greater than or equal to 100 bacteria per ml of blood, whereas CIE required greater than or equal to 1,000/ml. PRP accumulated with continuing blood stream infection, aiding detection of low-grade bacteremia. LPA detected antigen in cerebrospinal fluid (CSF) earlier in the course of meningitis and at a lower bacteria density than did CIE. Both methods detected antigen reliably with greater than or equal to 1,000 bacteria per ml of CSF. A close correlation existed between CSF concentrations of capsular antigen and bacteria (r = 0.90, P less than 0.001). We conclude that the LPA method permits earlier diagnosis of H. influenzae type b infection in part because of its greater sensitivity.
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PMID:Comparison of two antigen detection techniques in a primate model of Haemophilus influenzae type b infection. 11 34

The action of polylysines of various molecular weight on platelet behaviour is studied with the help of 3 techniques: photometric test, screen filtration pressure on PRP and electrophoretic mobility. Polylysines, which are polybasic substances, produce a platelet aggregation studied by photometry after a short period of latency. Aggregation, depending on the doses of poly-lysine and chiefly on the optic density, shows a "plateau" with the dose of 100 gamma/ml for poly-lysine L, of molecular weight 17000. The screen filtration pressure increases continuously in the presence of the polylysines studies. Finally, the platelet charge decreases. The results depend on the concentration of poly-lysine, and the optimal concentration which involves the more marked alterations is inversely proportional to the molecular weight of the polylysine studied.
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PMID:[Physicochemical study of platelet aggregation by 3 polylysines]. 13 31

1) On log-log-coordiantes a direct correlation has bee shown to exist between plasma cyclic AMP and plasma Cr levels. 2) hemodialysis results in a significant reduction in the arterial plasma cyclic AMP levels, but a return of plasma cyclic AMP to pre-dialysis levels is seen within 30 mins post-dialysis. 3) the dialyzer clearance of cyclic AMP, both in vitro and vivo, is commensurate with its M.W. 4) In vitro platelet aggregation responses, to ADP, EPI, and COLL are not influenced by PRP cell counts between 150,000 and 300,000/mm3. 5) the BT of NC and CHDP are not significantly different, indicating that the in vivo hemostatic properties of the CHDP are otherwise intact. 6)the CHDP have PVPC significantly lower than the NC, a finding commensurate with the usual mold thrombocytopenia of renal failure. 7)the aggreation responses of the CHDP to COLL and to both Lo and Hi concentrations of ADP and EPI are significantly less than those of the NC. 8)A statistically significant inverse correlation between aggregation response and plasma cyclic AMP is observed.
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PMID:Depressed in vitro aggregation of platelets of chronic hemodialysis patients (CHDP): a role for cyclic AMP. 16 91

102 sera from polytransfused patients have been screened in platelet aggregometry. Anti-human platelet isoantibodies, tested against 'responsive' human platelets in PRP, give in the aggregometer a decrease in optical density recorded as a sigmoidal curve. In the first step of reaction PF3 availability suggests that the primary action of antibody is to damage the platelet membrane. The second step might be a true aggregation (an ADP-mediated platelet clumping) or a platelet lysis, depending on the type and the potency of antibody, on the type of platelets (normal or thrombasthenic) and on some experimental conditions. These conclusions, confirmed by electron microscopy findings, suggest that aggregometry is a very rapid and simple method of detecting platelet antibodies.
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PMID:Platelet aggregometry and anti-platelet isoantibodies. 17 12


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