BackgroundThe term dangerous universal blood donor refers to potential agglutination of the erythrocytes of non-O recipients due to plasma of an O blood group donor, which contains high titers of anti-A and/or anti-B hemagglutinins. Thus, prior titration of anti-A and anti-B hemagglutinins is recommended to prevent transfusion reactions.ObjectiveThe aim of this study was to estimate the frequency of dangerous universal donors in the blood bank of Belo Horizonte (Fundação Central de Imuno-Hematologia – Fundação Hemominas – Minas Gerais) by determining the titers of anti-A and anti-B hemagglutinins in O blood group donors.MethodA total of 400 O blood group donors were randomly selected, from March 2014 to January 2015. The titers of anti-A and anti-B hemagglutinins (IgM and IgG classes) were obtained using the tube titration technique. Dangerous donors were those whose titers of anti-A or anti-B IgM were ≥128 and/or the titers of anti-A or anti-B IgG were ≥256. Donors were characterized according to gender, age and ethnicity. The hemagglutinins were characterized by specificity (anti-A and anti-B) and antibody class (IgG and IgM).ResultsAlmost one-third (30.5%) of the O blood group donors were universal dangerous. The frequency among women was higher than that of men (p-value = 0.019; odds ratio: 1.66; 95% confidence interval: 1.08–2.56) and among young donors (18–29 years old) it was higher than for donors between 49 and 59 years old (p-value = 0.015; odds ratio: 3.05; 95% confidence interval: 1.22–7.69). There was no significant association between dangerous universal donors and ethnicity, agglutinin specificity or antibody class.ConclusionEspecially platelet concentrates obtained by apheresis (that contain a substantial volume of plasma), coming from dangerous universal donors should be transfused in isogroup recipients whenever possible in order to prevent the occurrence of transfusion reactions.

<p><em>O presente trabalho teve por objetivo estudar a cinética de secagem em estufa através da obtenção de dados de secagem de suas curvas e aplicação dos modelos matemáticos aplicados à secagem de polpas de hidróxido de magnésio preparadas a partir da hidratação de duas fontes distintas de magnésia cáustica e de uma polpa de hidróxido de magnésio p.a., a título de comparação. As polpas preparadas a partir das fontes de magnésia cáustica foram obtidas por hidratação do óxido de magnésio em um sistema híbrido reator-moinho de bolas após 5 horas de reação. Para caracterização físico-química das amostras, foram utilizadas as técnicas de fluorescência de raios X e análise granulométrica por difração a laser. Os resultados mostraram alta velocidade de secagem das polpas com a etapa de secagem à taxa constante como sendo a controladora do processo, com transferência de calor e massa predominantemente a partir da superfície, apresentando um melhor ajuste ao modelo de Lei de Resfriamento de Newton.</em></p><p><em> </em></p><p><em>ABSTRACT</em></p><p><em></em><em>The aim of the present work was to study the kinetics of drying in stove by obtaining drying data of its curves and applying the mathematical models applied to the drying of magnesium hydroxide pulps prepared from the hydration of two different sources of caustic magnesia and one magnesium hydroxide pulp, for comparison purposes. The pulps prepared from the sources of caustic magnesia were obtained by hydration of the magnesium oxide in a reactor-ball mill hybrid system after 5 hours of reaction. For the physicochemical characterization of the samples, the techniques of X-ray fluorescence and granulometric analysis by laser diffraction were used. The results showed a high drying rate of the pulps with the drying step at constant rate as the process controller, with heat transfer and mass predominantly from the surface, presenting a better fit to the Newton Cooling Law model.</em></p>