Red cell antibodies and low ionic strength: a study with enzyme-linked antiglobulin test.

Alloantibody uptake on red blood cells was quantified with an accurate and reproducible enzyme-linked antiglobulin test. The uptake of anti-D, anti-Fy2 and anti-JK3 was markedly accelerated by low ionic strength salt solution (LISS) with a final ionic strength of 0.05 M.

Enzyme-linked antiglobulin test: an accurate and simple method to quantify red cell antibodies.

An enzyme-linked antiglobulin test was used to quantify the amount of IgG antibodies on red blood cells. Erythrocytes were sensitized with various blood group antibodies, washed, incubated with antiglobulin conjugated with alkaline phosphatase, washed, substrate was added and the optical density of the product was measured. This optical density was linearly proportional to the concentration of red blood cell antibodies incubated with the cells.

Problems in paternity testing. Subtypes of AB.

Paternity test results demonstrated that a child of type A1 has a mother who types as an A2B; the putative father is type O. According to the recent AMA-ABA joint report, these results prove nonpaternity. All other erythrocytic and HLA typing indicated a high probability that the putative father was the biologic father.

An unusual factor-X inhibitor in leprosy.

Two cases of Hansen disease demonstrating a lupus-like inhibitor directed against the activation of coagulation factor X are described. Each case showed factor-X activity markedly depressed by an inhibitor when measured in one assay system; yet normal levels were measured by three alternate factor-X assay systems.

Fibrinogen in cryoprecipitate and its relationship to factor VIII (AHF) levels.

Very little has been published to indicate the quantity of fibrinogen in cryoprecipitates. We assayed 88 preparations from five blood banks for factor VIII(AHF) and fibrinogen to assess whether the AHF assay can predict the fibrinogen content. Cryoprecipitate was considered to be consistent with FDA standards with 80 units of factor VIII/bag (40% yield from 200 ml plasma).

Transient bacteremia after dental procedures and other minor manipulations.

The devastating transfusion reaction that can occur after the infusion of blood contaminated with bacteria has prompted blood banks to adopt practices designed to minimize the possibility of bacterial contamination. There are four recognized sources of contamination of blood collected for transfusion: 1) prior contamination of the bag or the anticoagulant solution; 2) airborne contamination of the needle; 3) inadequate skin preparation including coring of the skin; and 4) bacteremia in the donor. The use of plastic collection bags and specially designed needles, and the recognition of the importance of aseptic technique have drastically reduced the incidence of serious transfusion reactions due to contamination.

Bovine plasma as a reference standard for the factor VIII assay.

Definition of one unit of factor VIII procoagulant activity may be imprecise, for a number of reasons. Levels in individual normal plasmas differ sufficiently that small pools do not have equivalent activities. Large pools cannot be prepared without loss of activity because of the lability of factor VIII.

Effects of lysozyme on Bacillus cereus 569: rupture of chains of bacteria and enhancement of sensitivity to autolysins.

Bacillus cereus 569 is known to be resistant to lysis by lysozyme because of the presence of deacetylated glucosamine residues in its peptidoglycan, and cultures continued to grow even in the presence of lysozyme at 200 microgram ml-1. However, lysozyme caused rupture of the chains of bacteria and promoted the rate of autolysis in a non-growing cell suspension, causing a doubling of the rate of release of radioactively labelled wall material. Heat-inactivated cells did not autolyse and were not lysed by lysozyme unless they were supplemented by unheated cells or cell-free autolysate.

A simple enzyme-immunoassay (EIA) test for factor VIII-related antigen (VIIIAGN).

An enzyme immunoassay (EIA) system has been developed to measure factor VIII-related antigen (VIIIAGN). This assay gives similar results to the commonly used Laurell electroimmunodiffusion (EID) assay for VIIIAGN as shown by comparison of both techniques with samples from healthy controls, patients with hemophilia A, and patients with von Willebrand's disease. The assay also has a greater precision than the EID technique as demonstrated by multiple assays of aliquots of a single sample.

Tn polyagglutination preceding acute leukemia.

Tn polyagglutination (persistent mixed-field polyagglutination) was detected in the blood of a 66-yr-old male laborer at the time of a splenectomy for life-threatening thrombocytopenia. Confirmation that the polyagglutination was caused by Tn activation was established by the use of lectins, by failure of the patient's red cells to react with sera from other patients with Tn polyagglutination, by weak aggregation with polybrene, by low red cell sialic acid levels, and by the persistence of polyagglutination over several years of testing. Two years after the discovery of the Tn polyagglutination, the patient developed acute myelomonocytic leukemia.

In vitro synthesis of peptidoglycan by beta-lactam-sensitive and -resistant strains of Neisseria gonorrhoeae: effects of beta-lactam and other antibiotics.

The synthesis in vitro of peptidoglycan by Neisseria gonorrhoeae was studied in organisms made permeable to nucleotide precursors by treatment with ether. Optimum synthesis occurred at 30 degrees C in tris(hydroxymethyl)aminomethane-maleate buffer (0.05 M; pH 6) in the presence of 20 mM Mg(2+).

Cryoprecipitate as a reliable source of fibrinogen replacement.

The recent withdrawal of commercial fibrinogen from the market makes alternate sources most important. Although it has been previously reported that single-donor cryoprecipitate contains appreciable amounts of fibrinogen, most clinicians need to be reminded of the reliability of cryoprecipitate for replacement of both fibrinogen and factor VIII. We assayed fibrinogen from 88 bags of cryoprecipitate prepared by five different blood banks in California and Oregon; we found that the average bag of cryoprecipitate contains at least 250 mg of fibrinogen depending on the volume of plasma processed.

Re-evaluation of plasmas from patients previously diagnosed as having von Willebrand's disease with the factor VIII-related antigen and ristocetin cofactor assay.

Diagnosis of deficiencies of coagulation factor VIII can be difficult to establish in some cases. The use of the factor VIII-related antigen and the use of the ristocetin cofactor assays have increased the reliability of diagnosis of factor VIII deficiency in patients with hemophilia A or von Willebrand's disease, and in carriers of hemophilia A. The authors re-evaluated samples, from frozen storage, of blood from patients previously diagnosed as having von Willebrand's disease.

Immunologic factors determining survival of cadaver-kidney transplants. The effect of HLA serotyping, cytotoxic antibodies and blood transfusions on graft survival.

We assessed immunologic factors determining graft survival in 510 recipients of primary cadaver allografts at one center. The degree of HLA match grade did not directly affect graft survival (54 per cent in no-antigen match, and 42 per cent in three-antigen match, at two years). There was no correlation between the HLA match grade and the degree of stimulation of the mixed lymphocyte culture.