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Biomedical subjects

B Bennett

Publications and source records attributed to B Bennett.

At least 271 records · Page 15Linked to original sources
PubMed1973

Studies on the nature of antihemophilic factor (factor VIII). Further evidence relating the AHF-like antigens in normal and hemophilic plasmas.

Normal human antihemophilic factor (AHF, factor VIII) and the protein antigenically related to it in hemophilic plasma both appeared in the void volume of columns of agarose (Sepharose 4B) during purification of these agents. On ultracentrifugation upon sucrose gradients, both agents had sedimentation characteristics similar to those of an S30 marker. After reduction, the polypeptide chains of purified normal AHF and of the nonfunctional agent from hemophilic patients had an apparent molecular weight of 200,000 as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These observations suggest that AHF, purified as described, exists as a large molecule with subunits of molecular weight of approximately 200,000. Antisera to normal AHF and the nonfunctional agent from hemophilic plasma appeared to be directed against antigens of similar electrophoretic mobility and precipitating characteristics, present in normal and hemophilic plasma but deficient in severe von Willebrand's disease plasma. Both antisera neutralized the AHF clot-promoting activity present in normal plasma, and this property was removed by absorption of the antisera with concentrates of normal or hemophilic plasma but to a greatly reduced extent by concentrates of von Willebrand's disease plasma. These findings suggest that the antigen detected in normal plasma by the antisera appears on a molecule participating in the AHF clot-promoting reaction.

Animals↗
PubMed1972

Studies on the response of patients with classic hemophilia to transfusion with concentrates of antihemophilic factor. A difference in the half-life of antihemophilic factor as measured by procoagulant and immunologic techniques.

Antihemophilic factor (AHF, factor VIII) levels were measured by a standard coagulation method and by an immunologic technique before and after infusion of AHF concentrates into patients with classic hemophilia. After infusion of AHF concentrates, the half-life of the AHF procoagulant (i.e., clot-promoting) activity varied from 12 to 14 hr, whereas that of the antigen ranged from 24 to 40 hr. The half-life of the antigen was similar in patients with and without circulating anticoagulants to AHF. The data are compatible with the suggestion that the antigen may be carried on a precursor molecule which the patient with hemophilia produces but cannot convert to the functional clot-promoting agent. Other explanations of the observations are, however, recognized.

Adult↗
PubMed1972

Immunologic studies in von Willebrand's disease. Evidence that the antihemophilic factor (AHF) produced after transfusions lacks an antigen associated with normal AHF and the inactive material produced by patients with classic hemophilia.

Antihemophilic globulin (AHF, factor VIII) levels were measured by a standard coagulation assay and by an immunological technique before and serially after infusion of fresh frozen plasma or cryoprecipitate into patients with von Willebrand's disease. Initial levels of AHF, measured both as procoagulant and as antigen, were low. Immediately after transfusions, the rise in levels of AHF-like antigen was compatible with the quantity of antigen present in the infused plasma or cryoprecipitate. Thereafter, levels of antigen declined rapidly and reached preinfusion values in approximately 24 hr. In contrast, procoagulant activity remained elevated, and sometimes continued to rise, for longer periods of time. One possible explanation of this finding is that the AHF molecule produced by patients with von Willebrand's disease, in response to transfusion of as yet unidentified factors, lacks the antigenic site associated with the normal AHF molecule or the inactive molecule produced by patients with hemophilia A.

Antigens↗