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A Bollini

Publications and source records attributed to A Bollini.

5 recordsLinked to original sources
PubMed2005

Study of intrinsic flow properties at the normal pregnancy second trimester.

During normal pregnancy the cardiovascular system undergoes extensive changes. In a previous work we demonstrated the role of the haemorheological profile as predictor of hypertensive gestational disorders through a retrospective study. In an attempt to clarify the rheological characteristics during normal gestation, blood and plasma viscosity, erythrocyte deformability and aggregation, and plasma fibrinogen levels were measured at second trimester of pregnancy. The interrelationships of different haemorheologic parameters, were analysed by Pearson correlation coefficient. The results showed decreased erythrocyte deformability, and increased plasma viscosity and erythrocyte aggregation due to increased fibrinogen in pregnant women. Despite these modifications blood viscosity did not increase, but there was a decrease in relative blood viscosity, therefore, a profile in accordance, from the haemorheological point of view, with the classical concept stating that haemodilution is of the utmost importance to maintain an adequate microcirculation in the uteroplacental unit during normal gestation.

Adolescent↗
PubMed2003

Proposal of a haemorheological profile for early detection of hypertensive gestational disorders.

The objective of this study was to emphasise the potential power of simple and inexpensive haemorheological tests as predictors of hypertensive gestational disorders through a retrospective study. Blood samples of 195 primigravids with gestational age 18-23 weeks were studied. For data processing pregnant women were allocated into 3 groups, based on difference of SBP and DBP values measured at first and last consultation, and presence of proteinuria and oedema: Normotensive pregnants (n=149), hypertensive pregnants; n=26 and preeclamptic pregnants; n=20. Whole blood viscosity, plasma viscosity, erythrocyte rigidity and aggregability, haemoglobin, hematocrit, total protein, albumin and fibrinogen were assayed. Increased relative viscosity (eta(r)) (p<0.01), decreased erythrocyte deformability (p<0.05), lower O(2) release (p<0.01) and birth weight (p<0.01), showed a negative correlation with filterability index in preeclamptics. There was a decrease of erythrocyte deformability in hypertensive women. Erythrocyte deformability and blood viscosity could be an early indicator in preeclamptics, and erythrocyte deformability in hypertensive ones, therefore they could be considered alert factors in order to decide a thorough control in these patients to prevent further complications.

Birth Weight↗
PubMed1998

Red blood cell shape as a function of medium's ionic strength and pH.

Glycocalyx, the characteristic first line of interaction between membrane and environment, can be visualized as a polyelectrolyte anchored to a bending-resistant matrix. This structure has an amazing resemblance with the ionized monolayers, in which, the cohesion among hydrocarbon chains is counteracted by the repulsion among similarly charged ionic heads, and thus the balance determines the curvature of the membrane. Likewise, it could be assumed that in biological membranes, repulsion among similarly charged groups in the glycocalyx could generate different curving trends. Hence, the factors directly influencing the electrostatic interaction among surface charged groups were studied, assessing the effect of the medium's ionic strength (mu) and pH, in an extensive range of values around the physiological one. The results point out mu variations inducing different shapes, depending on whether mu values were lower or higher than the physiological ones; which could be explained by the polyelectrolyte theory. The occurrence of more invaginated shapes as the medium's pH decreases, and the opposite event, when the pH increases, could be attributed to the coupling between the dissociation of the glycocalyx ionic groups and the H+ concentration. The behavior of the cells with reduced surface charges (by neuraminidase degradation) supports the hypothesis that the observed mu and the pH effect on erythrocyte shape could be mediated by glycocalyx charged groups.

Adult↗
PubMedDate not supplied

Kinetic model for erythrocyte aggregation.

It is well known that light transmission through blood is the most widely utilized method for the study of erythrocyte aggregation. The curves obtained had been considered empirically as exponential functions. In consequence, the process becomes characterized by an only parameter that varies with all the process factors without discrimination. In the present paper a mathematical model for RBC aggregation process is deduced in accordance with von Smoluchowski's theory about the kinetics of colloidal particles agglomeration. The equation fitted the experimental pattern of the RBC suspension optical transmittance closely and contained two parameters that estimate the most important characteristics of the aggregation process separately, i.e., (1) average size of rouleaux at equilibrium and (2) aggregation rate. The evaluation of the method was assessed by some factors affecting erythrocyte aggregation, such as temperature, plasma dilutions, Dextran 500, Dextran 70 and PVP 360, at different media concentrations, cellular membrane alteration by the alkylating agent TCEA, and decrease of medium osmolarity. Results were interpreted considering the process characteristics estimated by the parameters, and there were also compared with similar studies carried out by other authors with other methods. This analysis allowed us to conclude that the equation proposed is reliable and useful to study erythrocyte aggregation.

Blood Cell Count↗