A luminol-dependent chemiluminescence assay for the assessment of the phagocytosis of erythrocytes sensitized with anti-D IgG immunoglobulin by mononuclear leukocytes is described. The mononuclear leukocytes were obtained by apheresis enriched by centrifugation through a density gradient and stored in liquid nitrogen before use. The total reaction mixture, consisting of mononuclear leukocytes-luminol-erythrocytes (either anti-D IgG sensitized or unsensitized controls) was 500 microliters, light detection was by an LKB 1251 luminometer. Peak luminescence was seen between 35-45 minutes, the reaction being exhausted by 120 minutes. Determination of the reproducibility of the assay gave intra- and inter-assay coefficients of variation of 5% and 13% respectively. We found the chemiluminescent response to be affected by the number of erythrocytes used in the assay and by the composition of the medium in which the cells were resuspended, particularly the pH at the initiation of the assay. We also compared the chemiluminescence assay to a microscopic phagocytic assay and found the results virtually identical. However, the former chemiluminescence assay was much easier to perform, marginally more sensitive, less laborious and eliminated any possibility of subjective error.

Biological Assay↗

PubMedDate not supplied

Cardiac rehabilitation: participating in an exercise program in a quest to survive.

Cardiovascular diseases are the major cause of death in the United States. The American Heart Association reports that approximately 500,000 persons die each year from heart attacks. Cardiac rehabilitation programs are based on objectives that would, when adhered to, extend and improve an individual's quality of life after experiencing a cardiac event. The purpose of this qualitative study was to explore and describe strategies that individuals who experienced a cardiac event used to overcome barriers associated with an exercise program. The sample consisted of six subjects (four females and two males) who were enrolled in a cardiac exercise program for 1 year or longer, and who continued to actively participate in at least two cardiac exercise classes per year. This study revealed that individuals who consistently participated in a cardiac exercise program did not use strategies to overcome barriers; rather, in their quest to survive, they used strategies to ensure their participation in the program.

Adaptation, Psychological↗

PubMedDate not supplied

Albumin and pulmonary oedema.

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Animals↗

PubMedDate not supplied

Cryopreservation of human platelets with polyvinylpyrrolidone.

Fourteen polymeric compounds were assessed for their abilities to protect human platelets from injury during freezing and thawing. The effect of polymer concentration and molecular weight, cooling rate, platelet concentration, and short-term storage on platelet recovery were studied. Polyvinylpyrrolidone, average molecular weight 10,000, was found to provide the greatest degree of protection to platelets. Recoveries of platelets of from 60 to 80 per cent were achieved using a 5 per cent final concentration of polyvinylpyrrolidone and a cooling rate of 8 C per minute. Methods of freezing small aliquots of platelets and platelet concentrates were developed. The frozen-thawed platelets were viable in vitro as shown by osmotic reversal, clot retraction, and aggregation by collagen and adenosine diphosphate. The techniques described could be developed readily to facilitate the long-term storage of platelets.

Blood Coagulation↗

PubMedDate not supplied

Mouse monoclonal antibodies reacting with M blood group-related antigens.

Four mouse monoclonal antibodies were produced with specificities related to human blood group M antigen. The antibodies react in direct hemagglutination systems, and their specificities were investigated by their reactions with variant and enzyme-modified red cells. The effects of temperature and pH on their hemagglutination reactions also were investigated, and all four were murine IgG antibodies. Physicochemical and serologic investigations showed them to be four distinct antibodies, and each one could be used for M blood grouping under appropriate conditions.

Amino Acid Sequence↗

PubMedDate not supplied

The potentiation of "incomplete" mouse monoclonal anti-Lea agglutination with colloids.

Mouse monoclonal anti-Lea produced in this center was found to agglutinate only Le(a+) red cells which had been modified with proteases. In order to provide a stable medium in which the monoclonal anti-Lea would directly agglutinate unmodified red cells, the potentiating effect of a variety of colloids was assessed. Satisfactory results were obtained when 10 percent (wt/vol) dextran and 2 percent (wt/vol) bovine serum albumin were added to the culture supernatant containing anti-Lea. It is suggested that direct hemagglutination mediated by these colloids resulted from a combination of increased antibody uptake by Le(a+) red cells and change in the shape of these red cells induced by dextran.

Antibodies, Monoclonal↗

PubMedDate not supplied

pH effect on anti-M and anti-N reactivity.

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Animals↗