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Biomedical subjects

A M Ugolev

Publications and source records attributed to A M Ugolev.

At least 55 records · Page 3Linked to original sources
PubMed1986

A revision of current data and views on membrane hydrolysis and transport in the mammalian small intestine based on a comparison of techniques of chronic and acute experiments: experimental re-investigation and critical review.

Literature data and the results of our investigations using both generally accepted and original perfusion techniques of the isolated loop of the rat small intestine in in vivo experiments are reviewed. Significant differences in the functioning of the small intestine under conditions of acute and chronic experiments are revealed. It has been established that in chronic experiments as compared to acute ones: (a) the absorption of glucose, galactose, fructose and glycine is 2-5 times higher; (b) Kt as well as Jmax values of the transport of these nutrients differ considerably; (c) Na+-independent mechanism of glucose and glycine transport predominates; (d) higher rates of membrane hydrolysis and more effective interactions between enzyme and transport systems of the enterocyte brush border membranes are observed; (e) functional characteristics of the small intestine affected by various experimental factors are more stable. The conclusion is made that it is necessary to revise current views of the scale and regularities of digestive-transport processes in the small intestine under physiological conditions. The importance of the suggested approaches for general and comparative physiology and biochemistry is discussed.

Animals↗
PubMed1986

[Alanine aminopeptidases from small intestinal mucosa of dogs, rabbits and trout. I. Characterization of the "protease forms"].

Alanine aminopeptidases from the mucous membranes of the small intestines of dog, rabbit and trout were concentrated 200 fold in the case of dog and rabbit, and 15 fold in the case of trout. The enzymes were analyzed with respect to substrate specificity, effector behaviour, optimum pH value, Michaelis constants and molecular weight. The values obtained for these enzymes are not consistent in all points with those found for alanine aminopeptidases isolated from the mucous membrane of human jejunum and ileum.

Aminopeptidases↗
PubMed1986

[Alanine aminopeptidase from small intestinal mucosa of dogs, rabbits and trout. II. Behaviour of "detergent forms"].

Alanine aminopeptidases from the mucous membranes of the small intestines of dog, rabbit and trout were purified as detergent forms. The enzymes obtained were characterized with respect to substrate specificity, effector behaviour, Michaelis constants, molecular weight and temperature dependence. In comparison to data of the protease forms of the alanine aminopeptidases, differences could be demonstrated.

Aminopeptidases↗
PubMed1986

[Membrane digestion and some general problems in physiology].

A number of general problems arising from investigations of various aspects of membrane digestion has been considered in the paper. The development of this field of knowledge allowed to characterize from a new point of view the role of glycocalix, molecular physiology of intestinal enzymes, the role of recirculation of membrane proteins and intestinal barrier as well as the scale of membrane hydrolysis and transport in conditions approximated to physiological ones. The level of membrane hydrolysis and transport in vivo is several times that of in vitro experiments and of acute experiments in situ. From the data obtained it is evident that some present concepts of the level efficiency of in vivo physiological processes in the small intestine and mechanisms of their regulation ought to be reconsidered.

Amino Acids↗
PubMed1985

Comparative characterization of some enterocytic brush border membrane enzymes in mammals and fish.

The properties of the detergent- and protease-forms of alanine aminopeptidase and alkaline phosphatase of enterocytes in rabbits, cows, dogs and trout were investigated. The hydrophobic parts of the enzymes perform not only anchor functions, but also regulatory ones. It is suggested that these functions are of peculiar regularity, but vary in different enzymes of one species as well as in the same enzyme of different species.

Alkaline Phosphatase↗
PubMed1985

[Physiological substantiation and experience with the therapeutic use of oxygenated mineral water].

The accumulated experimental data indicate to the existence of two types of enterocyte respiration: apical and basolateral. Their interrelationships change with regard to small intestine function. Duodenal ulcer was chosen as a clinical model for a study of the therapeutic role of enteral oxygenation. Faster penetration of oxygenated mineral water into the duodenum was shown as compared to oxygen foam. Oxygenated mineral water therapy (as compared to water saturated with carbon dioxide and nitrogen) speeds up the rate of wound healing, shortens the time of arresting the pain syndrome and makes it possible to discharge patients earlier for outpatient treatment.

Adult↗
PubMed1985

Membrane digestion and transport under physiological conditions: a review of available data.

A technique to study membrane digestion and transport in the small intestine under physiological conditions has been developed. The technique is based on a continuous perfusion of a chronically isolated loop of the rat small intestine. Membrane hydrolysis and transport of some nutrients in the rat small intestine in chronic, as well as in acute (in situ) experiments was investigated. The absorption of hexoses and amino acids has been found to be 2.5-4 times higher under physiological conditions than in acute in situ experiments. Both the active transport of glucose released from maltose hydrolysis and the hydrolysis of the latter is increased under physiological conditions. A coupling between the final stages of hydrolysis and the initial stages of transport in chronic experiments was shown to be highly efficient; practically all or nearly all glucose released is being transported without entering the luminal phase. The hydrolysis rate of starch during the perfusion of a small intestinal segment in chronic experiments is many times higher than that in acute experiments or under anaesthesia. The enzymatic and transport activities revealed using a widely accepted technique in situ, the more so, in vitro account for only a small fraction of those which are typical of undisturbed processes under conditions close to the physiological. The levels of functioning of the digestive-transport systems of the small intestine considered as natural levels developed in the process of evolution, actually reflect only residual processes and, in most cases, they account for 1/3 to 1/10 of the true level of an actual physiological process.

Anesthetics↗
PubMed1984

[An isolated abdominal preparation in the rat].

A methodological approach proposed lies in the use of a complex abdominal preparation (an alimentary complex) of the gastrointestinal tract containing rat stomach, duodenum, small and large intestines and pancreas. The method is based on perfusion of the preparation vessels, namely of the vessels of the gastrointestinal tract or its parts both in situ and isolation of this alimentary complex. The alimentary complex is intended for solution of many problems of normal and pathological physiology, pharmacology and biology, permitting a deeper and broader insight into alimentary, transport, endocrine and regulatory functions of the gastrointestinal tract.

Anesthesia↗
PubMed1984

[Induced autolysis as an important mechanism of the initial stages of ordinary digestion].

The critical review of generally accepted ideas on initial stages of digestion in higher animals is presented. A brief account is given of the hypothesis of the induced autolysis as an important mechanism of food assimilation. According to this hypothesis digestive juices (in addition to their enzyme activities) contain factors capable to induce the autolysis of food structures. An attempt was made to estimate the value of gastric secretions and induced autolysis in the splitting of complex biological food structures. The splitting of native structures of food object was found to be more effective and complete than the splitting of the same structures subjected to heat denaturation. The results obtained suggest that the initial stages of digestion should be considered as a complex process provided both with the enzymes of gastric juice and with the enzymes of food itself, with lysosomal enzymes in particular.

Animals↗
PubMed1983

Comparative-molecular characterization of membrane digestion in fish and mammals.

The role of different parts of enzyme-membrane complexes in relation to the digestive membrane enzymes in some fish species of varying ecology are compared with those of the rat as a representative of homoiothermic animal. The activity of enzymes in various animal species at 25 degrees C, t degrees-function, Eact, Km and Vmax for different forms of alkaline phosphatase, sucrase and maltase is described. Adaptibility to a specific temperature is determined by both the phospholipid matrix and the enzyme protein globule including its hydrophobic part; their roles in adaptation of different enzymes (carbohydrases and alkaline phosphatase) differ.

Alkaline Phosphatase↗