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Biomedical subjects

A E Powell

Publications and source records attributed to A E Powell.

27 records · Page 2Linked to original sources
PubMed1971

Immunologic differentiation of classic hemophilia (factor 8 deficiency) and von Willebrand's dissase, with observations on combined deficiencies of antihemophilic factor and proaccelerin (factor V) and on an acquired circulating anticoagulant against antihemophilic factor.

Heterologous antiserum was prepared in rabbits against highly purified human antihemophilic factor (AHF, factor VIII). This antiserum blocked the clot-promoting properties of AHF and, when suitably absorbed, formed a single precipitin line against AHF upon immunoelectrophoresis. Material antigenically similar to normal AHF was detected in normal amounts in plasma concentrates in each of 22 patients with classic hemophilia, in a patient with an acquired circulating anticoagulant against AHF, and in a patient with deficiencies both of AHF and proaccelerin (factor V). AHF-like antigen was present in normal human serum. In contrast, material antigenically related to AHF was found in decreased amounts in the concentrates prepared from the plasma of 11 patients with von Willebrand's disease. The experiments described suggest that von Willebrand's disease is a disorder in which a true deficiency of AHF exists. Whether the AHF-like material found in classic hemophilia is nonfunctional through a defect in structure or through the intervention of an inhibitor has not been shown.

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PubMedDate not supplied

The long-term fate of fresh and frozen orthotopic bone allografts in genetically defined rats.

Fresh and frozen orthotopic iliac crest bone grafts in rats were studied histologically for determination of the long-term effects of histocompatibility matching and the freezing process on orthotopic bone graft incorporation. Grafts exchanged between groups of inbred rats, syngeneic or differing with respect to major or minor histocompatibility loci, were studied histologically at 20, 30, 40, 50, and 150 days after bone transplantation. A numerical histologic scoring system was developed and used by three observers for evaluation of coded hematoxylin and eosin sections. All frozen graft groups had the same fate regardless of histocompatibility relations between donors and recipients, and all grafts were inferior to fresh syngeneic grafts. Both fresh allograft groups received similar scores and initially at 20 and 30 days had scores similar to those of the fresh syngeneic groups. In the later intervals, however, the fresh allografts were inferior to the fresh syngeneic grafts and similar to the frozen groups. This is consistent with an older model describing two distinct phases of osteogenesis. In the long term, frozen syngeneic and fresh and frozen allografts across major and minor histocompatibility barriers were comparable, but all were significantly inferior to fresh syngeneic bone grafts.

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