Proliferation of poorly differentiated cells in the rat liver after a single injection of the hepatocarcinogen 4-dimethylaminoazobenzine and its noncarcinogenic analog

With the aid of autoradiography, the proliferation of non-differentiated (oval and transitional) cells in rat liver induced by a single injection of hepatocarcinogen 4-dimethylaminoazobenzene and its non-carcinogenic analogue has been studied. These cells are characterized by a high proliferative activity reaching its maximum 4 days after injection of both the agents. Later on, the proliferative activity decreased due probably to differentiation of such cells.     

The indices of systemic and regional hemodynamics in waking rats with streptozotocin diabetes]

Important cardiovascular dysfunctions have been described in streptozotocin (STZ)-diabetic rats. To determine the influence of these changes on the hemodynamic state, the different hemodynamic parameters, obtained by microsphere technique, were studied in STZ-induced (50 mg/kg) diabetic male Wistar rats, as well as in age control. All the rats were examined in the conscious, unrestrained state 12 weeks after induction of diabetes or acidified saline (pH 4.5) injection. During 12 weeks of the diabetic state the most important findings are hypotension, increase in cardiac index, decrease in total peripheral resistance and altered regional blood flow. These results suggest that important hemodynamic alterations are present in the chronic diabetic state.     

Differentiation of young black-faced buntings from the Primor’e population in the fall season based on remex molt analysis

Many bird molting characteristics are not only species-but also population-related. A study of postjuvenile molting in black-faced buntings has revealed substantial differences in the degree of molting in young birds from southern Primorskii krai in comparison with those from more northern populations (Khingan-Bureya upland). In Primor’e partial replacement of primaries is observed in young birds from the first broods. Measurements of feathers before and after molting have revealed a difference in the length of juvenile primaries between this and the next generation. On the basis of this difference, a procedure has been developed that allows us to differentiate a major part of black-faced buntings in Primor’e in the fall season.     

Reproductive function state of the scallop Mizuhopecten yessoensis Jay from polluted areas of Peter the Great Bay, Sea of Japan

The morphology of gonads and development of offspring of the scallop Mizuhopecten yessoensis sampled from six stations in Peter the Great Bay (Sea of Japan) were studied. The retardation of gametogenesis, oocytes resorption, autolysis of spermatozoa and their phagocytosis were observed in the gonads of the scallops from polluted sites. The number of hermaphrodites was about 6% against 0.3–0.4% in the scallop populations from clean areas. In the offspring development, a decrease in fertilisation success,diminution in percent of normal trochophores, D-veligers, veligers, and retardation of larval growth were recorded. The scallop populations inhabiting polluted areas of Peter the Great Bay seem to be incapable of normal reproduction. Development of offspring was a more sensitive index of disturbance of the reproductive function than morphology of scallop gonads. Analysis of the offspring development of common species of marine invertebrates is suggested to be used as a sensitive indicator of adverse environmental conditions. This revised version was published online in August 2006 with corrections to the Cover Date.     

Morphometric and cytochemical characteristics of the hepatocytes isolated from the liver of rats after a single exposure to 4,dimethylaminoazobenzene

Hepatocytes have been characterized that were isolated with sodium perchlorate from the livers of rats both intact and given a single injection of a carcinogen--4-dimethylaminoazobenzene. A decreased number of big hepatocytes (600-900 mkm2) and the appearance of small hepatocytes (75-120 mkm2) were observed 7 days after the carcinogen injection. An excessive accumulation of glycogen was shown in certain hepatocytes. By the 30th day the picture was nearly normal.     

Disruption of neurocognitive decision-making mechanisms in depression

To analyze the relationship of disruptions in neurocognitive decision-making mechanisms based on logic and reasoning, or in a situation of uncertainty based on emotional experience (emotional learning) with clinical indices of depression, a multidisciplinary clinical, psychological, and neurophysiological study was conducted in 28 patients suffering from depression (women aged 18–56) and 50 healthy volunteers (women aged 18–55). The intensity of depression was estimated quantitatively by the Hamilton’s Depression Rating Scale (HDRS-17) to qualitatively estimate cognitive functions, the “Ten Words” technique, the Wisconsin Card-Sorting Test (WCST), and the Iowa Gambling Task (IGT) were used; and to assess the functional brain state of all patients suffering from depression, a multichannel recording of the background electroencephalogram (EEG) was made. It was demonstrated that in depression, a neurocognitive deficiency was observed that correlates positively with the intensity of the depressive symptomatology. As well, a reduction occurs in the ability to make decisions based both on logic and reasoning (in the WCST), which is associated with EEG features of hypofrontality, and based on emotional learning (in the IGT test). Only in patients suffering from depression with a reduced ability to make rational decisions based on logic and reasoning was a “compensatory shift” observed toward decision making based on emotions, which leads to relatively higher indices of emotional learning. It is assumed that hypofrontality, which results in difficulties in making decisions requiring logical thought, leads to interruption of subcortical, including hippocampal, structures, an increase in the activation of which is related to better indices of emotional learning.