The influence of folate and antioxidants on homocysteine levels and oxidative stress in patients with hyperlipidemia and hyperhomocysteinemia.

The aim of this study was to observe the effect of folate and antioxidants alone on homocysteine levels and oxidative stress markers, and to evaluate whether their co-administration promotes their effects. One hundred patients with hyperhomocysteinemia were randomized into four equal groups, which were then treated with folate, antioxidants or folate plus antioxidants for 2 months; group IV was a control group. Serum homocysteine, folate and oxidative stress markers were measured before the study, at the end of folate and/or antioxidants administration and 3 months later. Folate caused a significant decrease in homocysteine concentration. Antioxidants did not influence homocysteine concentration, but they improved the antioxidative defense (plasma antioxidant capacity and intraerythrocyte glutathione were increased) and partially prevented lipid peroxidation (malondialdehyde level was slightly decreased). Supplementation with folate had a similar effect on intracellular glutathione and plasma malondialdehyde. Simultaneous administration of folate and antioxidants did not show any additive effect with the exception of a slower decrease of folate concentration after its supplementation had been discontinued. Folate may be considered as an effective antioxidant in patients with hyperhomocysteinemia; this can be a result of decreased production of free radicals due to a reduced level of homocysteine. Its antioxidative effect cannot be promoted by co-administration of antioxidants.

[The importance of blood gas analysis and acid-base equilibrium in pulmonary embolism]. / K významu analýzy krevních plynu a acidobazické rovnováhy u plicní embolie.

The authors examined in 60 patients with acute pulmonary embolism values of blood gases and acid-base equilibrium, incl. 30 from arterialized capillary blood, in another 30 subjects from arterial blood. On analysis of capillary blood hypoxaemia was present in all subjects, on analysis of arterial blood only in 63%. Respiratory alkalosis was found on capillary examination in 37%, on arterial examination in 23% of the patients. Hypoxaemia and hypocapnia thus are not specific phenomena in acute pulmonary embolism, in particular when accurate blood collection for analysis is respected, and normal values of paO2 and paCO2 do not rule out the presence of pulmonary embolism. In the development of hypoxaemia in patients with pulmonary embolism participates above all an incomplete right-to-left pulmonary shunt, as revealed during calculation of the magnitude of the shunt by means of the so-called oxygen method in 30 patients with embolism, as compared with a group of 10 healthy subjects.

[Comparison of the therapeutic effectiveness of membrane and centrifugation plasmapheresis]. / Srovnání úcinnosti lécebné membránové a centrifugacní plazmaferézy.

The authors compared 10 pairs of membrane plasmaphereses on an apparatus A 2008 PF and filter Plasmaflux P 2 with 10 centrifugation plasmaphereses on an apparatus Fenwal CS 3000. They evaluated the effectiveness by changes of plasma concentrations of total protein, albumin, beta 2 microglobulin, IgG, IgA, C3 complement, IgM, circulating immune complexes, urea, creatinine, uric acid, cholesterol, triacylglycerols and the clearance of these substances. Changes of plasma concentrations caused by plasmapheresis with the methods used did not differ in any of the investigated substances. The clearance of membrane plasmapheresis was for all substances higher than when the centrifugation method was used. Among values from which the clearance is determined no difference was proved between the two methods in the volume of exchanged plasma, the concentration of the substance in the removed plasma and its mid plasma concentration during the operation. The higher clearance of membrane plasmapheresis was due to the more rapid plasma exchange.

[Plasma proteins and other substances in membrane plasmapheresis. Relation to possibilities and limitations of this therapeutic method]. / Sledování plazmatických bílkovin a dalsích látek pri membránové plazmaferéze. Vztah k moznostem a omezením této lécebné metody.

The authors investigated the effectiveness of therapeutic membrane plasmapheresis and its influence on plasma concentrations of 17 proteins, cholesterol, triacylglycerols, urea, creatinine and uric acid. To this end they made 30 operations on monitors A 2008 PF with filters Plasmaflux P 2, where they exchanged one volume of plasma and replaced it with isooncotic albumin. They assessed the plasma concentrations of the investigated substances before, in the course of and after the operation, estimated sieving coefficients during the 15th and 90th minute and the clearance. Under conditions in vivo they confirmed that the sieving coefficients of the investigated substances approach the value of "1" and the clearance of the filtration rate, i.e. that the investigated substances pass easily through the plasmafilter and that plasmapheresis removes the substances non-selectively. They demonstrated that the assessment of plasma concentrations alone can lead to underestimation of the effectiveness of the operation. Assessment of sieving coefficients and clearance makes more adequate evaluation of the effectiveness of the procedure possible. Assessment of sieving coefficients and clearance made it obvious that plasma concentrations do not depend only on the amount of substance removed by plasmapheresis but also on other factors which must be investigated. The authors' findings support efforts to introduce methods for the selective removal of pathogenetic substances.