Biomedical subjects
Publications and source records attributed to Liliana Racca.
We report the case of a pregnant woman sensitized with a panreactive anti-Rh17 alloantibody. Patient's red blood cells showed a partial deletion of Rh antigens, which was responsible for the alloimmunization. An autotransfusion program was instrumented so as to cover possible demands. Molecular analysis of the RH locus showed the presence of a hybrid RHCE-D(5-7)-CE allele that gave origin to the deleted phenotype.
The aim of this study was to investigate the blood viscosity profile and to evaluate the influence of plasmatic (fibrinogen) and cellular (erythrocyte aggregation) factors in a group of hypertensive patients, compared with a normotensive group. We worked with anticoagulated blood of both non diabetic hypertensive patients (n=31), and healthy individuals (n=40). The plasmatic viscosity and whole blood determination were obtained with a cone-plate viscometer. Erythrocyte aggregation was studied by microscopical observation and quantified by an Aggregate Shape Parameter (ASP), defined as the relation projected area/perimeter. Fibrinogen was determined by the Clauss method with a coagulometer. A comparison between these groups led us to assert that whole blood viscosity was significantly higher in hypertensive patients than in the controls at all shear rates. Plasma viscosity values only showed significant differences between both groups at low shear rate (1.15 a 11.56 seg(-1)). The hypertensive patients showed irregular and amorphous aggregates so that ASP appeared significantly higher (p< 0.001) in patients with hypertension (0.69 +/- 0.11) than in healthy subjects (0.25 +/- 0.12). Fibrinogen appeared slightly higher (p<0.01) in the hypertensive group than in the normal group. Several hemorheological parameters play important roles in the pathogenesis of hypertension. Among these factors, several hemorheological parameters could be altered in hypertension (hematocrit, plasma fibrinogen level, erythrocyte deformability and aggregability, plasma and whole blood viscosity). An increased RBC aggregation has been identified as an important factor responsible for disturbing blood rheological behavior in the microcirculation. The present study demonstrates an abnormal erythrocyte aggregation, which was detected by increased ASP values that could be responsible for vascular complications in hypertension.
The main objective of the present work was to study modifications in RBC aggregate morphology by analyzing digitized microscopic images and compare them between healthy subjects and patients suffering from essential hypertension. Blood samples were obtained from normal subjects (n=30) and patients suffering from essential hypertension (n=20). RBC aggregate morphology was quantified using direct microscopic observation and numerical analysis of images. ASP (Aggregation Shape Parameter) defined as the ratio of the area of the projected image to its square perimeter was calculated. Other rheological parameters have been determined in order to establish the hemorheological profile of the studied hypertension states. ASP appears significantly higher (p<0.001) in patients suffering essential hypertension (0.69+/-0.11) than in normal control subjects (0.25+/-0.12). RBC aggregation is known to be responsible for the high increase in apparent blood viscosity at low shear rates. By compare ASP values with whole blood viscosity at low rate (2.30 s(-1)) a high correlation was formed between both parameters (Spearman coefficient was 0.8835 and p<0.001). The applied method is simple, direct and quantitative and provides a useful tool for measuring deviations of RBC aggregate morphology.