Coated platelets and severe haemophilia A bleeding phenotype: Is there a connection?

INTRODUCTION: Coated platelets are a subpopulation of platelets that possess highly prothrombotic properties. Previous observational data suggest that bleeding phenotype in severe haemophilia A is associated with coated platelet levels. Haemophilia A patients with higher coated platelet levels may have a mild bleeding phenotype; those with lower levels may have a more severe bleeding phenotype. AIM: The aim of the study was to test the hypothesis that coated platelet levels are correlated with clinical bleeding phenotype. METHODS: This cross-sectional, observational study enrolled 20 severe haemophilia A patients, including 15 with severe and five with a mild bleeding phenotype, and a control group of 12 healthy volunteers. The haemophilia bleeding phenotype was determined by the patient's medical history and haemophilia treatment centre records. Blood was obtained from each patient by venipuncture and platelets were analysed by flow cytometry. RESULTS: Patients categorized as having a severe bleeding phenotype experienced a median eight bleeds per year compared to one bleed annually in the mild bleeding phenotype group. Both groups had similar total platelet counts and fibrinogen levels. There was no difference in coated platelet percentage between severe and mild bleeding phenotype (17 and 16% respectively), however, both groups had significantly lower % coated platelets compared to controls (44%, P < 0.0001). CONCLUSION: Coated platelet levels were not associated with bleeding phenotype in this study; however, these data may suggest coated platelet levels are lower in haemophilia patients relative to healthy volunteers.

Passive reporting greatly underestimates the rate of transfusion-associated circulatory overload after platelet transfusion.

BACKGROUND: Transfusion-associated circulatory overload (TACO) is the second leading cause of reported transfusion-related fatalities in the United States. While its occurrence has been previously investigated after red cell and plasma transfusion, no data are available regarding its association with platelet transfusion. Our goal was to determine the rate of platelet-associated TACO at our university medical centre. STUDY DESIGN AND METHODS: This study had retrospective and prospective analyses. The 13-year retrospective analysis served to determine the historical rate of platelet-associated TACO by passive reporting. The 30-day prospective analysis included active surveillance of all non-emergently issued and non-operative platelet recipients ≥16 years old with no transfusions in the previous 6 h determined by analysis of blood bank product issue records. Data collected included demographics, vital signs pre- and posttransfusion, fluid balances, supplemental oxygen use, reports of dyspnoea, and infusion rates. For the prospective analysis, all variables were collected within 24 h of transfusion from the medical record and, when necessary, interviews with care providers and/or patients. RESULTS: In the retrospective analysis, 366 reactions were reported, of which 6 (1·6%) were TACO. The historical rate of TACO was 1:5997 transfused platelet units. During the prospective analysis, 225 eligible patients received a total of 334 units of platelets. The average platelet transfusion volume was 261 ± 26 ml, and the average infusion rate was 391 ± 198 ml/h. Two unreported TACO reactions were discovered and characterized by new-onset hypertension, crackles on lung auscultation, dyspnoea, hypoxia and supplemental oxygen requirements which resolved completely with diuresis. The rate of TACO during this prospective analysis was 1:167 transfused platelet units. CONCLUSION: Platelet-associated TACO is greatly underestimated by passive reporting in the adult patient population.

[Fibronectin and immune complexes in rheumatic diseases]. / Fibronektin i immunnye kompleksy pri revmaticheskikh zabolevaniiakh.

The review presents literature data on studies into fibronectin in rheumatic diseases of immunocomplex genesis, its contribution to the development of abnormalities in the immune system and to hemostatic processes in the diseases. The role of fibronectin in the clearance of immune complexes, disturbed metabolism products of connective tissue, fibrin, and its monomers, cell membrane receptor proteins is emphasized. Extracorporeal heparin precipitation by using fibronectin is ascertained to be promising in removing plasma proteins in rheumatic immunocomplex diseases. A possible involvement of fibronectin in the fixation of immune complexes and DNA on the basal membranes, followed by immunocomplex inflammation, in the fibrin-induced R protein retention in the body, suppression of local immunity reactions, and development of joint ankylosis in rheumatic arthritis.

[Modernization of a photoelectric transducer for liquid chromatography]. / Modernizatsiia fotoélektricheskogo datchika k zhidkostnomu khromatografu.

Photoelectric sensor for fraction automatic collector of liquid chromatograph which eliminates violation of the movable collector mechanism working rhythm, prevents liquid samples losses, excludes changes in fraction structures of the samples and pollution is described. The mentioned above benefits were gained due to replenishment of the unit with the industrial photoelectric sensor, which consists of the funnel with the through central opening, eccentrically located platform and a shaft with the longitudinal channel for the liquid to pass in the photoresistor plane and with the diametrically located window for the light bunch, coming from the lamp to the photoresistor, which signal is transferred to the movable mechanism.