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)

We have determined the minimal concentrations of 4 aggregating agents that were required to cause a 65-75% increase in light transmission without disaggregation during the 5-min recording period in PRP samples of 14 neonates and 10 adults. We found, for example, that this degree of aggregation could be elicited in adult PRP by a mean value of 2.09 micronM ADP, whereas similar aggregation of neonatal PRP required 5.16 micronM ADP. Based on these figures, we observed that adult PRP was about 2.5 times more sensitive to ADP, at least 10 times to epinephrine and 2.3 times to collagen than neonatal PRP. However, neonatal PRP was approximately 20% more sensitive to ristocetin than adult PRP. By using concentrations of aggregating agents that caused comparable aggregation of neonatal and adult PRP, we noted comparable inhibition of aggregation in these samples by aspirin. While neonatal PRP was less sensitive than adult PRP to physiological aggregating agents, there was no evidence that the former was more susceptible to in vitro aspirin inhibition.
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PMID:Comparable inhibition of aggregation of PRP of neonates and adults by aspirin. 86 93

Using a new method for the determination of split renal function with a radio-isotopic technique (FG Hipaque I131 and PRP Hippuran I131) we sought to determine residual renal function with pre-operative studies, especially in preparation for nephrectomy, and secondly with postoperative studies of compensatory renal hypertrophy after total or partial nephrectomy and the restoration of function in the kidneys following surgery of the urinary tract. A total of 20 cases was studied. We noted marked compensatory hypertrophy after total and partial nephrectomy and the prompt return of function after procedures involving the urinary tract, on condition that any acute infection be prevented.
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PMID:[Evaluation split renal function and compensatory hypertrophy using a radio-isotopic technique]. 91 86

In aged plasma or serum phosphatidic and lysophosphatidic acids (DAS) may occur which have been found to induce platelet aggregation in human and feline PRP (platelet rich plasma). Experiments performed on cats demonstrate that the lethal effect frequently following the i.v. injection of these substances into cats with high platelet counts is mediated via massive pulmonary microembolization. It remains to be elucidated whether the in vivo formation of these phospholipids may be of clinical interest.
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PMID:[The thrombocyte aggregating effect of phosphatidic acids and their lyso-derivatives (DAS)]. 92 37

When gel filtration is used to transfer platelets from plasma into an established environment, alterations in platelet characteristics may result from the change in environment or from the effects of platelet contact with the gel matrix. To approach the problem of evaluating the relative contributions from these sources, a Sepharose 2B matrix was employed and platelets transferred from citrate anticoagulated PRP into autologous PPP to yield plasma-GFP. Platelet recoveries averaged 93%. PRP: plasma-GFP pairs were found to be indistinguishable with respect to: morphology; ADP, thrombin or collagen-induced aggregation response; uptake of 5-hydroxytryptamine (5-HT) or adenosine; and thrombin or collagen-induced release of accumulated 5-HT or adenosine. Pairs are distinguishable by prostaglandin E2 synthesis assayed immediately after filtration.
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PMID:Effects of matrix contact during gel filtration of human platelets in plasma. 103 35

C-PRP clotted by reptilase does not retract due to the lack of activation of platelets. In order to support retraction, the platelets must undergo membrane changes resulting in contractile system activation. Only in the presence of aggregating agents capable of eliciting these membrane changes in vitro (e.g. ADP, adrenaline and collagen but not bovine fibrinogen or ristocetin), strong reptilase clot retraction (RCR) occurs. During RCR an aggregating activity, platelet factor 4, and retraction stimulating factor (RSF) were released, but acid phosphatase was not available. Not only inhibitors of platelet adhesion-aggregation reaction (PAAR) but also specific blockers of release are capable of inhibiting RCR. In coagulation disorders RCR was normal in most cases, but in thrombopathies different abnormalities of RCR were found. The RCR defect may be associated not only with a defect in the initial stages of PAAR, but in some instances also with a specific defect in release reaction. Besides inducer--"activated" platelets and their adhesion to polymerizing fibrin, the presence of divalent cations and free thrombocytar--SH groups is necessary for the retraction of reptilase clots.
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PMID:Reptilase clot retraction test. (Its cofactors and relation to other platelet functions). 109 91

Platelets from nine patients with storage pool disease (SPD) and from ten control subjects were isolated by gel filtration into a suspension medium permitting the direct determination of platelet Mg-2+, Ca-2+, and K+ levels. The total intracellular levels of ATP and ADP, as well as the incorporation patterns of 14-C-adenine into the metabolic nucleotide pool, were also determined in these platelet suspensions. The gel-filtered platelets (GFP) from SPD patients exhibited slightly lowered levels of ATP and substantially reduced amounts of ADP, in agreement with previous studies using PRP suspensions. Diminished aggregation responses to ADP, epinephrine, and to collagen in particular, similar to those observed previously in PRP, were obtained in GFP from SPD patients. However, GFP from the patients exhibited more variable aggregation responses to addition of ADP and epinephrine than did GFP from the control subjects. Increases in the extent of radioactive hypoxanthine formation, observed previously in normal platelets as a result of isolation into the suspension medium used in these studies, were significantly reduced in the GFP from SPD patients. The levels of platelet Mg-2+ and K+ determined in GFP from the patients were not significantly different from the levels of these ions in GFP from control subjects. However, substantial reductions in platelet Ca-2+ were found in the SPD platelets. A strong correlation was obtained between this reduction in platelet Ca-2+ and the reduction in ADP in these platelets. No such correlation was apparent between the ATP and Ca-2+ deficiencies. These results suggest that a major portion of platelet Ca-2+ may be located in the dense granules and support previous hypotheses that granular ADP and/or Ca-2+ may play a role in the release reaction. The finding of normal levels of platelet Mg-2+ and K+ in SPD platelets, however, suggests that these latter ions are not located in the dense granules.
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PMID:Metal ion contents of gel-filtered platelets from patients with storage pool disease. 113 23

A comparative study of ADP-induced aggregation was made in adult rabbits' intact and refractory platelets and in 7-day rabbits' platelets in vitro. Platelets of the young animals resembled refractory those of adults. The effect of ADP on platelets in vivo did not depend on the age of animals. Changes in platelet population composition of adult and 7-day rabbits during standard isolation procedure were compared. The platelets in PRP of young rabbits were damaged to a greater extent than those of adult animals. It is suggested that the refractory state of young animal platelets in PRP as obtained with the standard technique, could be attributed to their decreased resistance against mechanical forces.
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PMID:[A comparative study of the functional characteristics of thrombocytes at different stages of individual development]. 121 91

Retraction of platelet rich plasma clotted by reptilase is induced by electrical stimulation. Optimal retraction is obtained by stimuli, applied for more than 4 min, with the following characteristics: intensity = 150 volts, duration = 50 msec each, frequency = 10/sec. Electrically induced reptilase clot retraction is shown to be inhibited by EDTA, EGTA, methyl-xanthines, PGE1, acetylsalicylic acid, indomethacin, but not by apyrase or by phosphoenolpyruvate-pyruvate kinase and MgCl2. The results indicate that electrical stimulation induces retraction of PRP clotted by reptilase by triggering off an increased availability of Ca2+ in the intracellular space.
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PMID:Reptilase clot retraction induced by electrical stimulation. 125 Nov 42

Fifty children with Hemophilus influenzae meningitis have been enrolled in a prospective study. Patients were randomly assigned chloramphenicol or ampicillin treatment; there were no significant differences between groups in other respects. Countercurrent immunoelectrophoresis proved to be a valuable tool for rapid diagnosis of the causative agent even in pretreated patients. Increasing quantities of capsular polyribosephosphate antigen detected in the initial cerebrospinal fluid correlated significantly (r=0.62419; p less than 0.01) with early and late sequelae of meningitis. None of the patients died. Severe and persistent neurologic or intellectual deficits were noted in four (8%) of the children, and an additional 14 (28%) had IQ scores between 70 and 90. The presence of bactericidal antibody in serum was not protective. Anti-PRP antibody generally was not present in acute serum specimens and irrespective of the quantity of antigenic stimulus provided by the disease was nondetectable in 21 of 24 children less than 17 months of age following recovery.
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PMID:Prospective evaluation of treatment of Hemophilus influenzae meningitis. 125 9

In the PRP of anaphylactic rats, ADP, collagen and thrombin induced platelet aggregation was considerably reduced. Reduced aggregability could be transferred to normal platelets by suspending them in the PPP of anaphylactic animals and the impaired aggregation of platelets from animals undergoing anaphylaxis could be restored by exchanging their plasma for that of normal controls. Ellagic acid, a known activator of factor XII, produced similar alterations as obtained in anaphylactic shcok. It is suggested that the inhibition of platelet aggregation is due to the anaphylactic activation of factor XII and this mechanism may be of importance in rat anaphylaxis.
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PMID:Reduced aggregability of platelets in rat anaphylaxis. 126 97


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