Plasma xanthine oxidase level and alcohol administration

The acute administration of ethanol by gastric catheter significantly increases the plasma xanthine oxidase activity in both rats and hamsters without changing other enzyme activities--alanine aminotransferase and aspartate aminotransferase. The plasma xanthine oxidase level seems to be a sensitive marker of liver damage. Its higher activity due to the acute ethanol intoxication may have an impact on ethanol organ damage.

Lipid peroxidation on dialysis membranes

The aim of this study was to compare the changes of lipid peroxidation during haemodialysis (HD), using various types of dialyser membranes. A significantly higher concentration of total and free TBARS (thiobarbituric acid reacting substance) was found in blood and in plasma of HD patients, compared with the control group of blood donors. During the HD session the TBARS levels grow significantly, compared to the initial levels on both membranes (Alpha 500, Pro500), and are significantly higher after 15 min of HD on Alpha 500 membrane. The levels of TBARS appear to be significantly higher in patients on regular HD treatment, which may be due to a more intensive lipid peroxidation. There were significant acute changes in lipid peroxidation during one HD session. The changes in lipid peroxidation differ with the use of various HD membranes.

Plasma xanthine oxidase and resistance to hypoxia: effect of purines and alcohol administration

The administration of allopurinol significantly increased resistance to repeated hypobaric hypoxia, while hypoxanthine decreased it. The administration of adenine or inosine (25 mg/kg) was without effect. The results show pathogenic significance of xanthine oxidase-dependent production of free oxygen radicals in posthypoxic damage. In other experiments, the administration of 50% ethanol (12 ml/kg) by gastric catheter increased plasma xanthine oxidase activity in both rats and hamsters.

[Role of free oxygen radicals in the pathogenesis of internal diseases]

In the organism a part of molecular oxygen is converted into highly reactive radicals (superoxid, hydroxyl radical), which react with biological structures (proteins, nucleic acids, membranes). It is one of the general mechanisms of tissue damage, which occurs e. g. in ischemic reoxygenation, i. e. following intestinal, myocardial infarction; further in the site of inflammation the macrophages release superoxid extracellularly; in acute pancreatitis; in oxygenotherapy and other pathologic conditions. In all tissues there exists a protective system which, under physiological conditions, inactivates the toxic radicals. Enzymes (superoxid dismutase, physiological conditions, inactivates the toxic radicals. Enzymes (superoxid system, alpha-tocopherol, ascorbic acid are part of this system. The concept of tissue damage by radicals enables a new view on etiopathogenesis of some diseases and leads to endeavour to use the acquired knowledge in human medicine.

DNA content in nerve-cell nucleus. A biochemical and cytophotometric study of the rat cerebrum

The cerebral nuclei of 30-day-old rats were separated by a two-step gradient centrifugation into the fractions of large and small nuclei. The DNA content per nucleus was determined biochemically and cytophotometrically in these fractions as well as in the non-separated cerebellar and liver-cell nuclei used as reference cells. The DNA content of large and/or mainly neuronal, and the small and/or glial cell-enriched nuclei were 6.74 +/- 0.51 and 6.21 +/- 0.30 pg, respectively, and in the cerebellum 6.10 +/- 0.28 pg per nucleus. The DNA-content values determined cytophotometrically in Feulgen-stained samples of large and small bulk isolated cortical nuclei ranged within the diploid limits, indicated by a part of a liver-cell population measured in parallel. No evidence for the large scale existence of an "extra-DNA" reported earlier [Bregnard, Knuesel and Kuenzle (1975) Histochemie 43, 59-61; Bregnard, Kuenzle and Ruch (1977) Expl Cell Res. 107, 151-157; Kuenzle, Bregnard, Hübschner and Ruch (1978) Expl Cell Res. 113, 151-160] in cortical neurons has thus been obtained.

Effect of visual deprivation on protein and nucleic-acid content in cerebral cortex of rats after the eye-opening term

Between postnatal days 10 and 16 the cerebral cortex of rats displayed a rise in protein content and a tendency towards RNA increase, whereas changes in DNA content (cell density) were absent. Young rats whose eyelids had been sutured and covered with black collodion at the age of 7 or 8 days exhibited some developmental retardation already by day 16. At an age of 5 weeks the brains of control, eyelid-sutured and dark-reared rats did not differ in their weight. However, dark-reared rats had a highly significantly increased RNA concentration in the occipital cortex (not differing significantly from controls) than eyelid-sutured animals (p less than 0.005). In the remainder of cortex, eyelid-sutured animals displayed an increase (p less than 0.10) of RNA concentration as compared with controls. The most pronounced intergroup differences were found on comparing RNA, DNA and protein concentrations between occipital and residual cortices within the individual animal groups. The difference was practically nil in control animals; all components were highly significantly raised (RNA: p less than 0.001; DNA: p less than 0.01; protein: p less than 0.001) in the residual cortex in eyelid-sutured animals; dark-reared animals displayed a similar tendency as eyelid-sutured animals that, nevertheless, did not reach statistical significance.

Effects of early visual and complex stimulation on learning, brain biochemistry, and electrophysiology

A complex stimulation regimen (visual, auditory, and somesthetic-kinesthetic with forced movements, 30 times for 30 min each within 14 days) increased significantly the amplitudes of visual cortical evoked potentials (EPs) in adult rats if applied during the second postnatal fortnight. The EP increase after stimulation during the first 14 days after birth was not significant. Visual stimulation alone was compared with complex stimulation (visual plus forced movements) during the 2nd postnatal fortnight. More specific local changes in the visual cortex were revealed in brain biochemistry (lower DNA concentration, more RNA and protein per cell) and cortical electrogenesis (enhanced visual EPs) after visual stimulation alone, whereas complex stimulation induced more diffuse changes and rather profoundly influenced higher nervous functions (viz., memory retrieval - improved 24-h). Involvement of both specific and nonspecific mechanisms in the aftereffects of early stimulation is indicated.