The stability of factor VIII was studied in plasmas from patients on long-term warfarin therapy. The percent residual factor VIII activity (F.VIII:C) after incubation at 37 degrees C for 4 hr was higher in warfarinized patients than in normal subjects; 76.9 +/- 10.8% (mean +/- SD) of the initial F.VIII:C in the patients versus 61.6 +/- 5.8% in normal subjects (p less than 0.001). On the whole, neither protein C nor vitamin K-dependent coagulation factors except factor VII activity (F.VII:C) correlated with the residual F.VIII:C. There was a negative and weak correlation between the residual F.VIII:C at 4 hr and either the initial F.VIII:C or F.VII:C. Another experiment using protein C depleted plasma showed a relatively enhanced stability of F.VIII:C in the protein C deficiency. These results indicate that factor VIII is more stable in warfarinized plasma, and that protein C and vitamin K-dependent coagulation factors are not the sole, main factor responsible for such a phenomenon.

Blood Coagulation Factors↗

PubMed1986

Acquired and congenital von Willebrand factor abnormalities in congenital cardiac defects.

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Heart Defects, Congenital↗

PubMed1986

Further studies on aggregation of platelet-type von Willebrand's disease platelets by human von Willebrand factor.

Platelet-type von Willebrand's disease (vWD) is a bleeding disorder characterized by a heightened interaction between platelets and von Willebrand factor (vWF) as the result of an intrinsic platelet abnormality (probably in GPIb). Platelet aggregability was nearly normal in response to thrombin, wheat germ agglutinin and Ricinus communis agglutinin in this disorder. Unmodified platelets showed no aggregation upon the addition of peanut agglutinin. Partially purified human vWF induced little aggregation of washed patient platelets, but the aggregation was greatly enhanced in the presence of plasma devoid of vWF. Monoclonal antibodies directed against GPIb and GPIIb/IIIa as well as EDTA completely inhibited vWF-induced aggregation. These results indicate that human vWF induces aggregation of platelet-type vWD platelets in the presence of divalent cations and some plasma cofactor(s), and that both GPIb and GPIIb/IIIa are involved in this aggregation.

Antibodies, Monoclonal↗

PubMed1986

Quick diagnosis of malignant melanoma with the touch-fluorescence method during operation.

Nine cases of primary melanotic melanoma, three cases of metastatic amelanotic melanoma, and 26 cases of pigmented and unpigmented tumors other than melanoma were examined with the touch-fluorescence method using preparations from the cut surface of the lesions. Fluorescent melanoma cells were easily detected with a fluorescence microscope in all the cases of malignant melanoma whether the melanoma was melanotic or amelanotic. The fluorescent melanoma cells could be divided into three types by configuration: round, spindle-shaped, and pleomorphic. The main cell type of superficial spreading melanoma was round and that of nodular melanoma and acral lentiginous melanoma was chiefly pleomorphic. Fluorescent tumor cells were not seen in pigmented and unpigmented tumors other than melanoma, except in pigmented basal cell epithelioma; this fact made it possible to apply this method routinely for quick diagnosis of malignant melanoma during operation.

Adult↗

PubMed1986

Polymerization of amino acid under liposomal environment.

N-Carboxy anhydrides of amino acid derivatives with hydrophobic side chains, N-carboxy anhydrides of gamma-dodecyl L-glutamate and gamma-benzyl D-glutamate, were polymerized in bilayer membrane of large unilamellar liposomes prepared by the injection method. Infrared spectra indicated that polypeptides isolated from the liposomes existed in two different conformational forms, namely the alpha-helix and the beta form. Studying osmotic shrinkage of liposomes, it was found that liposomal membrane was highly permeable to glucose in the presence of polypeptides in the membrane.

Amino Acids↗

PubMed1986

DDAVP in acquired von Willebrand syndrome associated with multiple myeloma.

The response to a single intravenous infusion of 1-deamino-8-D-arginine vasopressin (DDAVP, desmopressin) was studied in two patients with acquired von Willebrand syndrome associated with IgG-kappa myeloma. Following infusion of DDAVP (0.3-0.4 micrograms/kg), prolonged bleeding time was normalized; plasma ristocetin cofactor activity, von Willebrand factor antigen, and factor VIII activity were remarkably increased; and high-molecular-weight forms of von Willebrand factor were demonstrated by crossed immunoelectrophoresis in both patients. Excellent hemostasis was achieved following administration of DDAVP in one patient when it was used for the treatment of gum bleeding and for the prophylaxis of bleeding during and after dental extractions. These observations suggest that DDAVP is an effective alternative to blood products for at least some patients with acquired von Willebrand syndrome in addition to patients with inherited von Willebrand disease, hemophilia A, and uremia.

Blood Coagulation Tests↗