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)

In this paper an in vitro culture system for the induction of an antibody response to the Haemophilus influenzae type b polysaccharide (PRP) is described. Anti-PRP IgM and IgG antibody-secreting cells (ASC) and anti-diphtheria toxoid (DT) IgG ASC were detected in cultures of blood B and T cells derived from donors 4 to 6 wk after immunization with Haemophilus influenzae type b oligosaccharide-mutant diphtheria toxin (CRM197) conjugate (HbOC) and required in vitro restimulation with HbOC. When lymphocytes from HbOC-vaccinated donors were stimulated with PRP, anti-PRP IgM and IgG ASC could be detected in 50% offGe cases. Lymphocytes from PRP-vaccinated donors or non-vaccinated donors consistently failed to generate anti-PRP antibodies after in vitro stimulation with HbOC. Optimal in vitro responses were observed at concentrations of 0.06 to 0.6 micrograms/ml of Ag. At higher doses of Ag (6 micrograms/ml) anti-PRP and anti-DT antibody responses were suppressed. The in vitro generation of anti-PRP and anti-DT ASC, as detected by a spot-forming cell assay was shown to be T cell dependent, Ag dependent, and Ag specific. This culture system provides a model for the study of human B cell activation and immunoregulation by polysaccharide-protein conjugates and polysaccharides.
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PMID:In vitro induction of a Haemophilus influenzae type b polysaccharide-specific antibody response in human peripheral blood lymphocytes of individuals recently vaccinated with an oligosaccharide-protein conjugate. 175 96

A possible role of platelet-derived 5-HT was examined concerning the pathogenesis of cerebral vasospasm. Intracisternal injection of 5 ml of platelet-rich plasma (PRP; approximately 7.5 x 10(8) platelets) induced not only acute (1 h) but also chronic (7 days) angiographically evident cerebral vasospasm in dogs. Sympathetic perivascular nerves on cerebral arteries showed no remarkable change following repeated injections of PRP, as the dense distribution of catecholamine-fluorescence and neuropeptide Y-like immunoreactive nerve fibers on Day 7 was comparable to findings in the preinjection controls. While there were no 5-HT-immunoreactive fibers in the cerebral arteries of control animals, numerous 5-HT-immunoreactive fibers were present in the PRP-injected animals. These results suggest that 5-HT, presumably released from extravasated platelets, may be taken up by nerve endings and act as a vasoconstrictor transmitter in the pathogenesis of chronic vasospasm.
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PMID:The role of platelets in the development of cerebral vasospasm. 175 84

Disease caused by H. influenzae type b is a world-wide problem of major proportions that affects both developed and developing countries. Young children are at particularly high risk of developing serious invasive infections. There has been tremendous recent progress in the development of vaccines that are immunogenic even in young infants. Clinical trials have demonstrated the efficacy of these polysaccharide-protein conjugate vaccines in infants. Two of these vaccines have been licensed in the United States for use in infants, and licensure of a third conjugate vaccine is expected soon. Many questions still remain to be answered. Are there significant differences in the efficacy for infants of the different licensed conjugate vaccines? Are the differences in the recommended schedules of immunization for the different vaccines justified? Would a combination of an initial dose of PRP-OMP (which is the most immunogenic vaccine in 2-month-old children) followed by subsequent doses of HbOC or PRP-T provide better overall protection than a schedule that uses only a single vaccine? Although much more research remains to be done, these vaccines, which have been recommended for routine universal immunization of infants in the United States, give us the capability of effectively preventing this potentially devastating infection of children.
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PMID:The epidemiology and prevention of disease caused by Haemophilus influenzae type b. 176 9

Invasive Haemophilus influenzae type b (Hib) infections carry high morbidity and mortality, primarily due to meningitis among infants less than 1 year of age. Two new vaccines, HbOC and PRP-OMP, have been developed and licensed to prevent invasive Hib infections in infants and young children. New recommendations advise clinicians to begin immunization for Hib at 2 months of age and to complete the designated series. This article details the new Hib immunization schedule for all pediatric clients between 2 months and 5 years. Additionally, public-health measures toward the prevention of serious pediatric morbidity and mortality are covered.
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PMID:New protection against Haemophilus influenzae type b infections in infants and young children. 176 98

Dipyridamole is widely used as a platelet function inhibitory drug. Its effect on platelet aggregation was investigated in a newly developed system, in which platelet aggregation was carried out in the presence of a human endothelial cell monolayer (EC). After iv. injection of 20 mg Dipyridamole platelet aggregation (inducer ADP 5 microM, Collagen 5 micrograms) was totally inhibited. The EC dependent antiaggregatory effect of Dipyridamol could be abolished if EC's were pretreated with 1 mmol ASA for 30 min. Our results, carried out in PRP demonstrate that Dipyridamole inhibits platelet aggregation even in the absence of red blood cells which were supposed to enhance the antiplatelet effect by their reduced adenosine uptake. Anenhanced PGI2 production in the EC's may explain the aggregation inhibiting effect of Dipyridamole in this test system.
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PMID:[Inhibition of induced thrombocyte aggregation in the presence of endothelial cells by dipyridamole]. 177 24

In the new countries of the Federal Republic Germany the incidence of systemic Hib-infections is lower than in the old FRG. In children under the age of 5 years the incidence of Hib-meningitis is 8/100,000 and of all systemic Hib-diseases about 17/100,000. By Hib-vaccination (PRP-D) severe diseases can be prevented. The recommended chemoprophylaxis with Rifampicin is important in this connection, too.
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PMID:[Type B Haemophilus influenzae infections: epidemiology, vaccination, chemoprophylaxis]. 177 52

A new method has been developed to investigate the direct effect of endothelial cells on platelet aggregation in the presence of cultured confluent human EC monolayers. The inside of the disk shaped cuvettes are covered by human umbilical vein ECs. The cuvettes rotate in the light beam of a photometer. In these cuvettes the effect of different aggregation inducers was inhibited in a concentration-dependent manner, e. g. for collagen at 0.5 microgram/ml, ADP at 5 x 10(-7) M, epinephrine at 5 x 10(-7) M and thrombin at 0.05 U/ml final concentration. (Platelet count 5 x 10(5)/microliters). Higher concentrations of the inducers led to irreversible platelet aggregation and were used for testing of antiplatelet drugs. In this system we detected a synergism between the antiaggregatory effect of the EC monolayer and that of SIN 1 (Cassella, Frankfurt/Main) the main metabolite of Molsidomine. 10 micrograms/ml PRP of SIN 1 alone partially inhibited platelet aggregation induced by 1 microgram/ml collagen and 10(-6) M ADP respectively in uncovered aggregation cuvettes. In the presence of an EC monolayer complete inhibition of platelet aggregation was obtained at a 5-fold final concentration of both inducers. After pretreatment of ECs with 1 mmol ASA over 30 min. the antiaggregatory effect of SIN 1 decreased, but was more pronounced (50%) than in uncovered cuvettes (25%).
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PMID:[Effect of SIN 1 on the interactions of endothelial cells and thrombocytes]. 177 29

A sensitive method, based on fluorescence detection, for the determination of thiamin derivatives after precolumn derivatization is described. The separation is achieved on a PRP-1 column using ion-pair reversed-phase HPLC. This method is especially well adapted to the detection of thiamin triphosphate in complex mixtures such as tissue extracts. The detection limit for TTP is 50 fmol. The contents of thiamin derivatives were determined in primary cultures of rat cerebellar granule neurons and cerebral astrocytes. The amount of TTP is about five times higher in neurons than in astrocytes. Thus in rat brain TTP seems to be essentially associated with neurons and the intracellular concentration is estimated to be about 0.2 microM. Our results suggest the existence, in nerve cells, of specific regulatory mechanisms not related to the blood-brain barrier and responsible for the maintenance of thiamin homeostasis in brain.
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PMID:Determination of thiamin and its phosphate esters in cultured neurons and astrocytes using an ion-pair reversed-phase high-performance liquid chromatographic method. 178 32

An enantioselective two-stage off-line assay has been developed for the analysis of hydroxychloroquine and its three major metabolites in biological fluids. The first non-stereoselective stage of the assay (PRP-1 column) separates and quantitates parent drug and metabolites. Fractions containing hydroxychloroquine and each of the metabolites are collected manually, evaporated, reconstituted in mobile phase and re-injected onto an alpha 1-acid glycoprotein column to separate and determine proportions of individual enantiomers. Preliminary results from patients samples indicate that the disposition of hydroxychloroquine and its major metabolites is enantioselective. p6
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PMID:High-performance liquid chromatographic separation of the enantiomers of hydroxychloroquine and its major metabolites in biological fluids using an alpha 1-acid glycoprotein stationary phase. 179 17

The present in vitro study of the effects of iron on the blood coagulation mechanism in rats showed that addition of ferrous sulphate to pooled rat plasma resulted in inhibition of blood coagulation, as shown by prolongation of the clotting parameters tested, an effect which was dose-dependent. In vitro addition of ferrous sulphate to rat PRP in doses of 2-5 mg/ml significantly decreased platelet aggregation in response to ADP, while collagen-induced aggregation was significantly diminished in presence of the higher doses of ferrous sulphate (4-5 mg/ml). Also, preincubation of ferrous sulphate with thrombin or with pure fibrinogen indicated that iron could produce decrease of thrombin activity as well as impairment of fibrinogen clottability. In vitro addition of copper sulphate (300-1000 micrograms/ml) elicited an anticoagulant effect, though thrombin time was markedly shortened with all tested concentrations of copper sulphate. Addition of copper sulphate to PRP produced inhibition of platelet aggregation in response to PRP produced inhibition of platelet aggregation in response to ADP and to collagen. Preincubation of copper sulphate with thrombin resulted in slight enhancement of thrombin activity followed by inhibition, while preincubation of copper sulphate with pure fibrinogen caused only minimal impairment of fibrinogen clottability. Also, addition of gold chloride in doses of 50-500 micrograms/ml to plasma in vitro produced a dose-dependent progressive prolongation of all clotting parameters tested, the effects reaching a maximum after 30 min. incubation. Further the in vitro addition of gold chloride to rat PRP resulted in marked inhibition of platelet aggregation in response to both ADP and collagen. In addition, preincubation of gold chloride with thrombin or with pure fibrinogen showed that gold exerted an antithrombin action and prolonged the fibrinogen clotting time indicating impaired fibrinogen clottability.
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PMID:In vitro effects of trace elements on blood clotting and platelet function. A--Iron, copper, and gold. 180 Jun 20


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