Statically controlled cooling rate device.
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Blood Platelets↗
Biomedical subjects
J H Pert
Publications and source records attributed to J H Pert.
Detection of hepatitis B antibody by a single-antibody radioimmunoassay.
A radioimmunoassay (RIA) for the measurement of antibody to hepatitis B surface antigen (anti-HB-s) in human and non-human sera is described. The principle is based upon our earlier observation that anti-HB-s and hepatitis B surface antigen (HB-s-Ag) are soluble in 4.5% w/v polyethylene glycol 4000 but that anti-HB-s-HB-s-Ag complex is precipitated. The use of activated charcoal suspended in polyethylene glycol and dextran solution facilitated the separation of this complex by centrifugation, thus improving reproducibility and sensitivity. The test is approx. 3-5000 times as sensitive as counterelectrophoresis. In a survey of a normal blood donor population, with an incidence of approx. 0.1% positive for HB-s-Ag by RIA, 7-8% were found to have anti-HB-s by this method.
Animals↗
An immune hemagglutination procedure with very high sensitivity applied to the detection of hepatitis B antibody and antigen and immune complex.
An immune agglutination procedure is described in which red cells are coated with antigen and agglutination is observed after a short incubation with antibody in reagent serum. Conversely, the cells may be coated with antibody and used to test for the presence of antigen. Treatment of the reagent serum with cobra venom factor results in inhibition, and there is a marked lo-s of sensitivity with cells pretreated with formalin or chromic chloride, suggesting that C3 and some type of reactive sites on the cells are required. The distinctive features of the new procedure are that incubation time is very short, sensitivity is several orders of magnitude higher than with other related tests, and, within some limitations, bovine (steer) red cells with bovine serum can be used as an alternative to human red cells with human serum. It is necessary to remove an inhibitor from the reagent serum, human or steer. While the mechanism of the procedure needs further elucidation, the findings reported here suggest that it ought to be sufficiently sensitive to detect hepatitus B antigen if present in virtually any blood sample. With appropriate modifications it should be useful for blood donor screening, diagnosis, and for studying many other antigen-antibody systems.
Adsorption↗
Large-scale blood-screening program for hepatitis B.
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Blood Donors↗
Evaluation of platelet cryopreservation techniques by isolated kidney perfusion.
The isolated perfused rabbit kidney, a model system used previously to assess platelet function, was adapted for evaluation of human platelet cryopreservation techniques. A new, simple, efficient device for controlling cooling rates before, during, and after freezing was used. Platelet concentrates frozen with 5 per cent dimethyl sulfoxide (DMSO) under different conditions were the most effective of those tried in maintaining the hemostatic function and vascular integrity of perfused kidneys. Our studies indicate that the isolated, perfused rabbit kidney can be used to evaluate platelet cryopreservation techniques and is potentially adaptable for studies of organ cryopreservation.
Animals↗
A simplified method for freezing human blood platelets in glycerol-glucose using a statically controlled cooling rate device.
An inexpensive, statically controlled cooling rate device consisting of a cassette of aluminum plates and cardboard insulation in a plastic bag was used to freeze platelets in liquid nitrogen with glycerol-glucose as cryoprotectant. Depending on the thermocouple location, the cooling rate in the freezing bag varied between 22.1 and 38.6 C per minute, averaging 33.6 +/- 1.1 C per minute at the center. The post-thaw recovery of platelets frozen with this device and reconstituted in plasma averaged 88.6 +/- 11.7 per cent, compared to 86.1 +/- 9.9 per cent for nonfrozen, but otherwise identically processed platelets. 14C Serotonin uptake after 0.5-hour incubation was 95.9 +/- 1.9 per cent for fresh platelets in platelet-rich plasma, 92.7 +/- 4.4 per cent for nonfrozen processed platelets, and 81.4 +/- 11.8 per cent for frozen platelets, increasing to 85.9 +/- 7.7 per cent after one-hour incubation.
Blood Platelets↗