British journal of haematology
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Case Reports
Sustained correction of the bleeding time in an afibrinogenaemic patient after infusion of fresh frozen plasma.
We have evaluated the duration of the effect of replacement therapy with two different doses of fibrinogen on the prolonged bleeding time of an afibrinogenaemic patient and the relationship between changes in bleeding time and plasma and platelet fibrinogen concentrations. The infusion of 40 mg/kg fibrinogen, as fresh frozen plasma (FFP), corrected the prolonged bleeding time of the patient from longer that 30 min to 8 min. ⋯ The bleeding time returned to the prolonged baseline values only by day 6 post-infusion, when plasma and platelet fibrinogen levels were 4 x 10(-4) g/l and 1.4 micrograms/10(9) platelets. Therefore, sustained correction of the prolonged bleeding time may be obtained in afibrinogenaemic patients with a single infusion of fibrinogen at lower doses than usually recommended.
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Transfusion medicine laboratories routinely perform a series of pretransfusion serological tests including: ABO grouping, Rh typing, and investigation of the recipient's serum to detect antibodies against blood group antigens (antibody screen). As a final check, most laboratories also perform a crossmatch in which the recipient's serum is incubated with the donor's red cells followed by the addition of an antiglobulin reagent (antiglobulin crossmatch). The need for the antiglobulin crossmatch when the antibody screen is negative has been questioned because there are few antibodies that are detected by this test. ⋯ There were 27 transfusion episodes where the antiglobulin crossmatch on blood transfused was positive due to an IgG antibody. Even though these transfused red cell concentrates were designated incompatible by the antiglobulin crossmatch, none of the patients receiving this blood had clinical or serological evidence of haemolysis. We concluded that the antiglobulin phase of the crossmatch can be omitted from pretransfusion testing without putting patients at risk.
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Although the mechanisms involved in the persistent clinical complications of sickle cell disease have not yet been fully delineated, previous studies suggest that sickle cell (HbSS) patients have a disposition to generate more thrombin and plasma in vivo than normal subjects. The reasons for the impaired regulation of haemostasis in HbSS patients is poorly understood. We report studies evaluating the extent to which in vivo coagulation and fibrinolysis are altered in HbSS patients in steady state. ⋯ These results strongly suggest accelerated in vivo coagulation and fibrinolysis in HbSS patients even during steady state. They are consistent with the hypothesis that haemostasis is less tightly regulated in the HbSS patients than in HbAA controls. The altered regulation of haemostasis may contribute to the initiation of vaso-occlusive processes associated with sickle cell painful episodes.
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We have used X-linked restriction fragment length polymorphism (RFLP)-methylation and gene deletion analyses to investigate the nature of the progenitor cell of origin in the myelodysplastic syndromes (MDS). Gene deletion studies were performed on the granulocyte and T-lymphocyte fractions of six women with refractory anaemia (RA) and either a partial deletion of the long arm of chromosome 5 (5q-) or monosomy 7. ⋯ These studies have confirmed the monoclonality of the granulocytes and the polyclonality of the T-lymphocytes in these cases. Our findings suggest that in this group of patients with MDS the T-lymphocytes were not involved in the disorder, and furthermore, in the one case where B-lymphocytes were also available, that the progenitor cell of origin was restricted to the myeloid lineage.