[The diagnostic characteristics of von Willebrand's disease]. / Osobennosti diagnostiki bolezni Villebranda.

70 patients from 48 families were examined. Of them, 59 (84%) patients had type I Willebrand's disease (WD), 9 (13%) type II, 2 (3%) type III WD. Hemostasis was assessed by functional tests: APTT, FVIII activity, bleeding time, ristocetin-cofactor activity of plasma Willebrand factor (WF). The WF levels in plasma and platelets were measured on a Reader-210 Microwell system by enzyme immunoassay with 380 F2 monoclonal antibodies to human WF. The functional parameters in 65 patients in remission were within normal range in half the patients. The only objective diagnostic criterion of the patients inclusion into WB group was the level of WF in plasma, especially when patients with type I WD were examined. The level of WF was always low in patients of this group even in the presence of normal values of functional tests. The severity of WD course and definition of laboratory signs of the disease depended mainly on the involvement of platelet WF in pathological process. In patients with a decrease of both plasma and platelet WF the course of the diseases was most serious and laboratory data most shifted from normal.

[Immunoenzyme method of determination of Willebrand's platelet factor]. / Immunofermentnyi metod opredeleniia trombotsitarnogo faktora Villebranda.

A method for Willebrandt factor antigen measurement in platelets has been developed based on indirect solid-phase enzyme immunoassay with monoclonal antibodies. The mean platelets Willebrandt factor level in 17 normal subjects was 21.5% (S = +/- 8.88; S mean = 2.16%). The method was tried in a group of patients with Willebrandt's disease. A relationship was demonstrated between Willebrandt platelet factor level and the degree of disorders in hemorrhage duration.

[Detection of the heterozygote carrier state and prenatal diagnosis of hemophilia A using DNA probes]. / Vyiavlenie geterozigotnogo nositel'stva i prenatal'naia diagnostika gemofilii A pri pomoshchi DNK-zondov.

Southern blot analysis of DNA samples from 110 persons related to 30 high risk hemophilia A families was carried out using intergenic probe St-14 and intergenic probes p 51-61 and p 1.8. Thirty-five hemophilia A patients, 24--their mothers--obligatory carriers and 51 close proband relatives were studied altogether. 16 female proband relatives were diagnosed as hemophilia A carriers, hemophilia A heterozygosity was rejected in three persons. Twenty five families were found to be at risk for prenatal hemophilia A diagnosis. One case of hemophilia A diagnosis in a 10-week fetus has been presented.

[A modification of a method of evaluating the coagulation activity of factor VIII]. / Modifitatsiia metoda otsenki koaguliatsionnoi aktivnosti faktora VIII.

The authors suggest that factor VIII activity be calculated relative to the value of activated partial thromboplastin time of substrate hemophilic plasma. This value is determined by replacing the tested plasma in the reaction mixture with veronal-acetate buffer. This modification has been developed to eliminate the shortcomings of the single-step technique for measuring this factor activity, that are explained by the use of nonstandard donor plasma and by the necessity to have such plasma during the investigation. A formula has been derived for the calculation of factor VIII coagulation activity in hemophilic patients and the advantages of the suggested modification are demonstrated.