The interaction of temperature and fish size on growth of juvenile turbot

Growth rate of tagged juvenile turbot was significantly influenced by the interaction of temperature and fish size. The results suggest the optimum temperature for growth of juvenile turbot in the size range 25–75 g is between 16 and 19°C. Optimal temperature for growth decreased rapidly with increasing size, and is between 13 and 16°C for 100 g turbot. Although individual growth rates varied highly at all times within the temperature treatments, significant size rank correlations were maintained during the experimental period. The study confirms that turbot exhibit ontogenetic variation in temperature optimum, which might partly explain different spatial distribution of juvenile and adult turbot in ocean waters.     

A Simple,Flexible Failure Model

A new failure model is introduced in the form of a four-parameter nonlinear differential equation, with failure probability as the dependent variable and failure time as the independent variable. The first parameter characterizes the location, the second the scale, and the other two the shape of the model. The type of the accompanying hazard function is immediately read off the shape parameters. The new model approximates the classical failure models with rather high precision, but also models cases where the failure density is skewed to the left. It can be used to analyze survival data objectively, based on the shape of the failure distribution. The computation of quantiles and moments is easy and fast. Nonlinear regression methods are used to estimate parameter values.     

Role of the vagus nerve in mechanisms of the modulation of afferent duodenal effects]

The electrostimulation of vagal nerves, the effect of naloxone and atropine on duodenal afferentation by registering evoked potential (EP) at cortex on direct electrostimulation of duodenum have been studied in acute experiments on cats. It has been established that the stimulation of afferent portion of vagal nerves causes the effect of deprivation of EP, whereas the stimulation with certain intensity of efferent portion of vagal nerves intensifies the duodenal afferentation. The effect of afferentation easeness (relief) has been blocked by the application of naloxone 10-20 microgram on duodenal bulbus, but not on it's i. v. injection and without effect on local application of atropine. It is concluded that the role of vagal nerves on the modulation of duodenal nociception is due to the activation of opiate terminals of the efferent vagal nerve portions.     

Lipid metabolism in experimental virus infections]

The effect of herpes simplex virus (HSV) and influenza virus (IV) on lipid metabolism was studied. In conditions of acute herpetic infection of rabbits we detected typical dyslipidemia, characterized by increased contents of total cholesterol, beta-cholesterol and triglycerides in the absence of trustworthy differences in concentrations of alpha-cholesterol. The use of antiherpetic preparation furavir, on the background of infection, corrected lipid spectrum of the infected animals. Blood lipid disturbances in acute influenza virus infection of mice were not detected. HSV infection of cell culture of human aorta was accompanied by increased accumulation of free lipids in cells. IV infection, in the same conditions of experiment, did not change the contents of intracellular lipids. The obtained data deepen the existing notions of herpetic and influenza infections pathogenesis and may be useful in understanding etiopathogenesis of certain somatic metabolism diseases.     

Hibernation activates glyoxylate cycle and gluconeogenesis in black bear brown adipose tissue

Biochemical studies on brown adipose tissue removed from a hibernating black bear and a non-hibernating control animal demonstrate that this tissue: (1) can carry out cyanide-insensitive fatty acid oxidation, and (2) possesses catalase activity and the enzyme activities unique to the glyoxylate cycle, isocitrate lyase and malate synthase. These activities are all markedly increased in brown fat obtained from the hibernating animal. Additionally, hibernation enhances the ability of the tissue to synthesize glycogen in the presence of a fatty acid substrate. The glyoxylate cycle enzymes and the ability to convert fatty acid carbons to glucose have been generally regarded as being absent from vertebrate cells and tissues.     

Four-stranded DNA helices: conformational analysis of regular poly(dT).poly(dA).poly(dA).poly(dT) helices with various types of base binding

The paper presents results obtained in conformational analysis of homopolymeric four-stranded poly(dT).poly(dA).poly(dA).poly(dT) DNA helices in which the pairs of strands with identical bases are parallel and have a two-fold symmetry axis. All possible models of base binding to yield a symmetric complex have been considered. The dihedral angles of sugar-phosphate backbones and helix parameters, which are consistent with the minima of conformational energy for four-stranded DNAs, have been determined using the results of optimization of conformational energy calculated at atom-atom approximation. Potential energy is shown to depend on the structure of base complexes and on the mutual orientation of unlike strands. Possible biological functions of four-stranded helices are discussed.     

Effects of adaptation to exposure to short-term stress on indices of resistance of energy metabolism and contractile function of the myocardium to acute hypoxic hypoxia and reoxygenation

Effect of preliminary adaptation to immobilization stress with progressive duration from 15 min. to 1 h (every second day, 8 sessions) on the resistance of indices of myocardial energy metabolism and contractile function to acute hypoxic hypoxia and subsequent reoxygenation was studied. It was shown, that adaptation to short-term stress exposure by some way provided the retention of activities of important enzymes like creatine-phosphokinase and phosphorylase under the harmful action of acute hypoxia and subsequent reoxygenation. At the same time, the ATP restoration and the CP super-restoration were observed during reoxygenation. This effect, in its turn, was accompanied by a more pronounced super-restoration of the heart contractile function than in control.     

Characteristics of the course of regeneration process in the muscles of replanted rat extremities

The analysis of the changes in the muscles of replanted terminals in early and late stages was made by the method of electron microscopy. In early stages neurogenic atrophy was observed which progressed due to the destructive-regenerative process caused by incomplete innervation, deepening microcirculatory disorders and, likely, autoimmune reactions.