Effect of vitamin B6 on gamma-aminobutyric acid level in rat brain.

Vitamin B6 injected intraperitoneally into rats 400 mg/kg body weight, has produced a statistically significant decrease in GABA level concentrations in hippocampus and cerebellum. Cerebral cortex, caudate nucleus and thalamus have shown the decrease in GABA concentrations, but these changes were not statistically significant. No remarkable behavioural changes were noted under such circumstances. The possible functional meaning of these results is discussed in relation to the role of GABA distribution in different brain regions and development of convulsions.     

Enzymes of cyclic nucleotide degradation in eye tissues during experimental ocular herpes

Activity of phosphodiesterases disintegrating cAMP and cGMP in the cornea, sclera and ciliary body was investigated in health and in different stages of experimental herpetic keratitis. The problems concerning the role of the cyclase system in the pathogenesis of herpetic keratitis and the possibility of applying some of the drugs to the disease treatment are discussed.     

Phospholipid oxidation catalyzed by cytochrome c in liposomes

Oxidation of liposome phospholipids has been studied in the presence of cytochrome c. Sonicated vesicles of soya bean or egg-yolk lipids, or purified phospholipid preparations, were treated with oxidized cytochrome c at a 10:4 lipid/protein ratio (w/w). Lipid peroxidation was examined by oxygen polarography, gas-liquid chromatography (GLC) and the thiobarbituric acid test. Oxidized, but not reduced, cytochrome effectively catalyzes lipid oxidation under these conditions. Oxygen consumption and disappearance of unsaturated fatty acids follow closely similar patterns, the O2 consumption rate showing a maximum (1.53 mol O2/min per mol heme) shortly before fatty acid loss reaches its peak. GLC and O2 consumption data suggest that monohydroperoxides are the most abundant oxidized species in the system. The thiobarbituric acid reaction, however, appears only to be of qualitative value in peroxidation studies. In order to test the mechanism through which oxidation occurs in our system, the effect of liposome composition and the presence of antioxidants was tested, both on cytochrome c binding to bilayers and on O2 consumption. Oxidized and reduced cytochrome c bind the lipid bilayers with similar affinity, but only the oxidized form is active in autoxidation. Antioxidants do not modify either cytochrome c binding to sonicated liposomes. Lipid composition does influence considerably cytochrome binding, and O2 consumption is correspondingly altered. Studies with various antioxidants and inhibitors suggest that both free radicals and singlet oxygen may be involved in the process under study.     

Erythrocytic diagnostic agents for determining antibodies to Proteus O antigens

Highly sensitive and specific erythrocyte diagnostic agents (ED) for the determination of antibodies to Proteus O-antigens have been obtained by the sensitization of formolated sheep red blood cells (SPBC) with activated lipopolysaccharides (LPS) without the use of mediators. The tannin treatment of formolated SRBC and/or the increase of temperature from 45 degrees C to 100 degrees C in the process of the preparation of ED have been found to produce no increase in effectiveness. Antibody ED permitting the detection of Proteus O- and H-antigens has been obtained by the sensitization of formolated chick red blood cells with immunoglobulin preparations to Proteus hydroxylamine antigens, carried out with the use of amidol. The experiments have shown the possibility of using this antibody ED for the determination of O-antibodies in the antigen neutralization test with nonactivated LPS used as an agglutinating agent. The passive hemagglutination test with antibody ED has proved to be a more sensitive method for the detection of O-antibodies than the antigen neutralization test with antigenic ED. The determination of Proteus etiology in the passive hemagglutination test with the use of antigenic ED has been shown to be highly effective in the examination of patients with chronic osteomyelitis at the stage of exacerbation.