[Alteration in superficial anionic charge of erythrocytes and desialated erythrocytes caused by Ascaris lumbricoides].

Introduction: Sialic acid of the erythrocytes has hemorreologic and hemodynamic importance, so its reduction causes erythrocyte aggregation and low blood flow.

Objective: To study the effect of A. lumbricoides on the anionic charge of erythrocytes and of desialated erythrocytes, taking the time of contact of the erythrocytes with parasite extracts into account.

Methods: Twenty parasite extracts and Group O erythrocyte suspensions in saline medium (GR) and in bromelin enzymatic medium (GR(b)) were used. The erythrocytes were treated by incubating the globular sediment with the same volume of parasite extracts, at 37 degrees C for 15, 30, 45, 60, 90 and 120 min. There was a control for each treatment interval (erythrocytes without contact with parasite extracts). The polybrene's method was simultaneously applied to the controls, the GR ad the GR(b). Each obtained aggregation was given a scoring. C(exp)CAS[EA) was calculated as the quotient between the treated erythrocytes scoring and the control.

Results: the statistical analysis allowed arriving to the conclusion that the time of GR and GR(B) treatment had a highly significant effect on the value of C(exp) CAS[EA]; the median of C(exp) CAS[EA]; was significantly higher for GR than for GR(B); the sialic acid uptake in GR was higher from 90 minutes on, whereas this parameter was lower in G(B) at 15 min; no significant differences were observed for the rest of the treatment times. The results showed that the sialic acid uptake by the parasite depended on the time of treatment and that the parasite extract caused more alteration in the superficial charge of GR(B).

Conclusions: The reduction of sialic acid could be related to thrombosis and anemia in ascariosis. The experience gained allows us to consider that the effect of the parasite may be more significant in diabetic and hypertensive individuals.