Study to evaluate the encephalotropic potency of a hemodialysate. Controlled study using electro-retinography and visual evoked potentials under hypoxic conditions in human volunteers (preliminary communication).

Twelve healthy young males volunteered in this pilot-study to test the encephalotropic potency of a deproteinized hemodialysate of calf blood (Actovegin). This compound contains peptides, oligosaccharides and nucleinic acid derivatives, which are supposed to improve transport of glucose and oxygen into cells. The study is based on a placebo-controlled, partially double-blind, 3-way crossover design. The subjects received single administrations of the hemodialysate as injection (10 ml, 400 mg), as infusion (500 ml, 4 g) and a placebo injection (saline) in randomized sequence. Drug effects on visual evoked potentials (VEP) and electro-retinography (ERG) were tested--in the context of a hypoxia based model of dementia (10.5% O2 inspiratory)--1, 2, and 4 h post administration. The main target variables were the amplitudes of the VEP-P2-component and of the ERG-b-wave. The hemodialysate--as an encephalotropic drug--was expected to counteract the hypoxia-induced reduction of both amplitudes. On a descriptive/exploratory level the restitution of the (hypoxia-suppressed) target variables was found. The combined application of visual evoked potentials (VEP) and of electroretinography (ERG) was able to consistently reveal central and peripheral sites of hypoxia-antagonistic action of the drug in study, which might not be restricted solely to neuronal structures, but seems to be extended to glial structures too. The predominant effects form a pattern of clinically relevant changes, which should be confirmed in a larger number of subjects. The preferable form of administration--featuring positive effects in hypoxia antagonism--seems to be the infusion with its higher dosage.(ABSTRACT TRUNCATED AT 250 WORDS)