Laboratory and clinical study of nitazole]

Nitazole, a drug from the nitrotiazole group, was shown to be active in vitro against bacteroides, peptococci, peptostreptococci, clostridia, staphylococci, colibacilli and streptococci. By its activity and antibacterial spectrum nitazole had some advantages over metronidazole, a drug from the nitroimidazole group. Experimental study of nitazole aerosole formulation in 4 models of purulent wounds of rabbits infected by Bacteroides fragilis, B. melaninogenicus, Clostridium perfringens 27 and Staphylococcus aureus 209P revealed its high therapeutic efficacy. In the treatment of 37 patients with purulent wounds of the soft tissues including 12 cases isolating anaerobic microbes, the clinical process of the acute suppuration in all the patients at the average reduced to the 5th-7th day. By the data of the bacteriological and cytological examinations the wound surface was ready for putting in stitches or free perforated cutaneous graft by the 10th-12th day. The drug tolerance was good. No adverse reaction were observed under the nitazole dressing in any case during the treatment of the wounds.     

Microbial ecology of the intestines in health and in pathology

Bifidoflora constitute 85--95 per cent of the large intestine microbiocenosis in children under 1 year of age. Bacteroides are not specific of children under 6 months of age. Lactobacilli, lactic acid streptococci, colon bacilli, enterococci and staphylococci (saprophytic, epidermal) constitute not more than 15 per cent. The predominating group peculiar of eubiosis in adults includes bifidobacteria and bacteroides. Changes in human autoflora are often induced by such factors as impaired ecology, stress, uncontrolled use of antibacterial drugs, radio- and chemotherapy, etc. Dysbacteriosis (first of all lower quantitative contents of bifidoflora) has an unfavourable effect on the intestine secretory function, absorption and certain indices of protein, lipid and mineral metabolism, vitamin synthesizing and fermentative functions and leads to disfunction of the gastrointestinal tract. It is a cause of persisting and relapsing infections in children and adults. High and optimal levels of bifidoflora in the intestine usually prevent the pathogenic action of pathogens. Lysozyme of digestive secretion and secretory immunity with immunoglobulin A prevalence also play an important role in the complicated mechanism of the protective barrier. The use of bacterial preparations such as bifidumbacterin, lactobacterin or bifilact for stabilization and recovery of high bifidoflora levels is indicated in all the cases with impaired microbiocenosis of the intestine.     

Actin interaction with the plasma membrane fraction of the cells from a suspension subline of murine L fibroblasts

Effect of plasma membranes of murine fibroblasts cultivated in suspension on actin polymerization was studied. Using low shear viscometry of actin-membrane mixtures together with the number of extractions of membranes with actin depolymerizing buffers it was found that at least two polypeptides 220 and 94 kDa may be involved into the actin filaments-plasma membrane interaction.     

The effect of insulin on the catalytic efficacy of rat skeletal muscle hexokinase isoenzyme II]

The effect of insulin on the intracellular localization of rat skeletal muscle hexokinase isozyme II (hexokinase II) was studied in vivo. It was found that after injection of the hormone the glucose concentration in the muscle gradually increases in parallel with the hexokinase II redistribution between the cytosol and the mitochondrial fraction in the direction of the bound form of the enzyme. This effect of insulin is due to glucose, an indispensable participant of the complex formation between the enzyme and the mitochondrial membrane. It was shown that the effect of glucose as a hexokinase II adsorbing reagent is a highly specific one. The hexokinase II binding to mitochondria in the presence of glucose is accompanied by changes in some kinetic properties of the enzyme. A kinetic analysis of catalytic efficiency of the free and bound hexokinase II forms revealed that the catalytic efficiency of hexokinase II within the composition of the enzyme-membrane complex exceeds by two orders of magnitude that of the free enzyme. The data obtained are discussed in the framework of an adsorption mechanism of hexokinase activity regulation in the cell.     

Skin electrical activity of the stomach and intestine during long-term antiorthostatic hypokinesia

The skin electrical activity of the gastrointestinal tract in the stomach and small intestine frequency ranges was studied for four months in 13 men under the conditions of antiorthostatic hypokinesia (AOH). On an empty stomach, both the gastric and small intestine electrical activities increased to a level comparable with that of the increase detectable after eating under the conditions of normal motor activity, whereas the response to food stimulation was inhibited. The ratios between the parameters of spectral analysis testified to a higher tonic component in the stomach and a higher peristaltic component in the intestine under the conditions of AOH. The observed changes in the gastric and intestinal electrical activities were observed against a background of a hypersecretory state of the stomach and an increase in the intestinal contents. During the readaptation period, both the gastric and intestinal electrical activities increased significantly, whereas the response to food stimulation was inhibited.     

Functional Body Capacities under the Conditions of Various Concentrations of Carbon Dioxide and Oxygen

We determined a permissible ratio between carbon dioxide and oxygen concentrations during accidental situations. The experiments (n = 138, 10 h each) on the effect of various concentrations of carbon dioxide and oxygen in the inhaled air were conducted on male volunteers aged 20–40 years subjected to a special medical examination. All experiments were divided into five series: hypercapnia + normoxia, hypercapnia + hyperoxia, hypercapnia + hypoxia, normocapnia + hypoxia, and ambient air (control). The results showed that functional capacities of the body are less impaired under the conditions of hypercapnia combined with hyperoxia. Thus, in accidental situations associated with rapid accumulation of carbon dioxide in the atmosphere of airtight chambers, a synchronous increase in pO₂ to 220–230 torr can provide for the highest work capacity.     

APOE ε4 moderates abnormal CSF-abeta-42 levels,while neurocognitive impairment is associated with abnormal CSF tau levels in HIV+ individuals – a cross-sectional observational study

Background

Cerebrospinal fluid (CSF) biomarkers Aβ1-42, t-tau and p-tau have a characteristic pattern in Alzheimer’s Disease (AD). Their roles in HIV-associated neurocognitive disorder (HAND) remains unclear.

Methods

Adults with chronic treated HIV disease were recruited (n = 43, aged 56.7 ± 7.9; 32% aged 60+; median HIV duration 20 years, >95% plasma and CSF HIV RNA <50 cp/mL, on cART for a median 24 months). All underwent standard neuropsychological testing (61% had HAND), APOE genotyping (30.9% carried APOE ε4 and 7.1% were ε4 homozygotes) and a lumbar puncture. Concentrations of Aβ1-42, t-tau and p-tau were assessed in the CSF using commercial ELISAs. Current neurocognitive status was defined using the continuous Global Deficit Score, which grades impairment in clinically relevant categories. History of HAND was recorded. Univariate correlations informed multivariate models, which were corrected for nadir CD4-T cell counts and HIV duration.

Results

Carriage of APOE ε4 predicted markedly lower levels of CSF Aβ1-42 in univariate (r = -.50; p = .001) and multivariate analyses (R² = .25; p < .0003). Greater levels of neurocognitive impairment were associated with higher CSF levels of p-tau in univariate analyses (r = .32; p = .03) and multivariate analyses (R² = .10; p = .03). AD risk prediction cut-offs incorporating all three CSF biomarkers suggested that 12.5% of participants had a high risk for AD. Having a CSF-AD like profile was more frequent in those with current (p = .05) and past HIV-associated dementia (p = .03).

Conclusions

Similarly to larger studies, APOE ε4 genotype was not directly associated with HAND, but moderated CSF levels of Aβ1-42 in a minority of participants. In the majority of participants, increased CSF p-tau levels were associated with current neurocognitive impairment. Combined CSF biomarker risk for AD in the current HIV+ sample is more than 10 times greater than in the Australian population of the same age. Larger prospective studies are warranted.

     

The role of the antioxidant system in the mechanism of adaptation to intensive noise

It has been shown in the experiment with albino rats that the prolonged influence of stable noise (90 dB) results in a shift of the redox equilibrium in the thiol-disulphide and ascorbate systems of the adrenal gland and myocardium tissues towards oxidation and the activity of glucoso-6-phosphate dehydrogenase and superoxide dismutase decreases. A concept on the pathogenetic role of the redox equilibrium disturbance in the thiol-disulphide system, in particular, in the development of noise pathology is suggested.     

Evaluation of thermal resistance of <Emphasis Type="Italic">Azotobacter chroococcum</Emphasis> 66 using atomic force microscopy

A possibility to use atomic force microscopy (AFM) for comparative analysis of thermal resistance of Azotobacter chroococcum 66 cells has been studied. The sizes of bacteria cells and the structuredness of the cytoderm have been shown to vary depending on the dose of hyperthermic action and on the composition of the media for heating and subsequent incubation. A thermally induced increase of a standard roughness parameter (R _a) and of cell sizes has been revealed to reflect an increased level of their resistance to hyperthermia.