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Biomedical subjects

J R O'Brien

Publications and source records attributed to J R O'Brien.

At least 145 records · Page 8Linked to original sources
PubMed1970

A comparison of an effect of different anti-inflammatory drugs on human platelets.

Different doses of aspirin, indomethacin, paracetamol, benorylate, and sodium salicylate were taken by four volunteers. The minimal dose that altered a platelet function test and the persistence of this alteration at different dose levels were studied. Minute doses of indomethacin (0.035 mg/kg) were effective but the effect of even a large single dose did not persist. A tenth of the therapeutic dose of aspirin (1 mg/kg) was effective, and higher doses altered the platelets' function for several days. Benorylate in a high therapeutic dose gave aspirin-like results. Paracetamol and sodium salicylate were relatively inactive. The persistence of the aspirin effect may be related to the acetyl group. These findings are surveyed in relation to a general theory of the action of anti-inflammatory drugs.

Acetaminophen↗
PubMed1970

Some effects of mucopolysaccharide stains on platelet aggregation.

FIVE MUCOPOLYSACCHARIDE STAINS INHIBIT PLATELET AGGREGATION INDUCED BY SEVERAL AGGREGATING AGENTS: with two stains inhibition is competitive. Alcian blue, 0.05 mg/ml, added to platelet-rich plasma potentiates ADP-induced aggregation. Alcian blue, 0.5 mg/ml, itself produces platelet aggregation, probably causing the release reaction. Three of these stains produce aggregation of red cells. They also bind heparin, and so may influence heparin-neutralizing sites (platelet factor 4) and probably the charge on the platelet membrane. The only known common factor to these stains is their ability to bind onto the mucopoly-saccharides. It is suggested that when platelets are ;stained' the surface mucopolysaccharide is altered and that this alteration can influence platelet aggregation.

Binding Sites↗
PubMed1969

Comparison of the effect of heparin and citrate on platelet aggregation.

When whole blood was passed through a column of glass beads, heparinized and native blood gave similar results. With citrated blood far fewer platelets were lost on the column. Thus citrate inhibits this test and heparin has no effect.Platelet-rich plasma (PRP) was prepared from citrated and heparinized blood and the responses in a number of aggregation tests were compared. With added adenosine diphosphate and adrenaline (first wave), the response in heparin PRP was greater than that in citrate PRP and was proportional to the amount of free calcium ions. With added collagen and adrenaline (second wave) the response was worse in heparin than in citrate platelet-rich plasma. It is concluded that heparin has no effect on the adhesive forces but inhibits the release mechanism. This may be of therapeutic importance.

Adenine Nucleotides↗