Action of alcohol in chronic emotional pain stress in rats

Male albino rats were exposed to daily emotional painful stress (EPS) for 4 weeks. The arterial blood pressure of the stressed animals increased and the dynamics of the heart rate changed after functional loading (hypokinesis during one or two hours) as compared with the control group. The increase of the heart weight and activation of cytochrome oxidase activity in the cerebral cortex and hippocampus of rats exposed to EPS were also demonstrated. The use of 20% ethyl alcohol instead of drinking water during EPS partially prevented vegetative disturbances and activation of hippocampal cytochrome oxidase and fully prevented the heart hypertrophy and activation of the enzyme in the cortex. Alcoholization resulted in the increased weight of the spleen and brown adipose tissue and thymus involution. A possible mechanism of the antistress action of alcohol linked with normalization of intensified lipid peroxidation under stress is discussed.     

Stimulation induced recurrent epileptiform discharges block cortical and subcortical spreading depression in rats

Blockade of the spread depression [SD] in chemically or electrically stimulated areas of the cerebral cortex was analyzed in a series of experiments performed in 40 curarized, locally anaesthetised rats. Longlasting stimulation of the cerebral cortex (0.5 to 1.7 mA, 6 Hz, 0.1 ms) elicited recurrent episodes of enhanced evoked potentials propagating to remote cortical areas [Co], the caudate nucleus [Cd], the hippocampus [Hi] and the thalamus [Th] and was accompanied by marked slow potential shifts (4-6 mV amplitude, 2-3 min duration, at 2-5 min intervals]. The projected discharge interfered with SD initiation and propagation in all the examined structures. The SD blockade was most pronounced during the episodes and almost absent in the intervals between them. The block was manifested by reduced amplitude and duration of the slow potential of SD. Pentobarbital [20 mg/kg] suppressed the recurrent discharges and eliminated the corresponding SD blockade. Recurrent excitability changes induced by Cd and Th stimulation elicited similar effects but the threshold was higher in Cd and Th than in Co. SD was less effectively blocked by the projected discharge than by stimulation of the same structure, particularly in the vicinity of the recording electrodes, where the blockade could be observed even under pentobarbital. The SD blockade outlasted stimulation by a considerably longer period of time in Th (about 10 min) than in the Cd (about 3 min). The onset of stimulation and the projected episodes sometimes elicited SD waves but SD blockade prevailed with continued stimulation. The present findings support the hypothesis that excessive neural activity increases the potassium clearance and thus prevents the autoregenerative accumulation of potassium ions, mediating SD propagation.     

FMN-reductase from Escherichia coli and its effect on the activity of luciferase from marine bacterium Vibrio fischeri]

Interactions of luciferases isolated from Vibrio fischeri 6 and Escherichia coli JM109(pF3) (bearing cloned V. fischeri luxAB genes) with FMN reductase isolated from E. coli JM109 were studied. FMN reductase formed a stable complex with luciferase, suggesting similar properties of the FMN reductases in the taxonomically close families Vibrionaceae and Enterobacteriaceae.     

Effect of T-activin on the production of immune interferon

A study was made of the effect of T-activin on the biosynthesis of immune gamma-interferon. It was shown that in 27% of patients with chronic nonspecific pulmonary diseases, production of gamma-interferon by lymphocytes was substantially reduced during exacerbation of inflammatory process in the lungs. It was discovered that T-activin was not an interferon inductor but enhanced its synthesis in patients with a low capacity of producing immune interferon even at small doses of interferon inductor. The preparation does not produce any effect on this process in normal subjects and in patients showing the normal level of gamma-interferon. Thus T-activin can be used for stimulation of interferonogenesis.     

Selecting high-dimensional mixed graphical models using minimal AIC or BIC forests

Background  

Chow and Liu showed that the maximum likelihood tree for multivariate discrete distributions may be found using a maximum weight spanning tree algorithm, for example Kruskal's algorithm. The efficiency of the algorithm makes it tractable for high-dimensional problems.