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Biomedical subjects

D A Mel'nichuk

Publications and source records attributed to D A Mel'nichuk.

At least 19 recordsLinked to original sources
PubMed1990

[Adenosine triphosphatase from plasma membranes of cattle intestinal epithelium].

The activities of Na,K-, Ca,Mg- and Mg-ATPases in the membrane fractions of plasma membranes of intestinal enterocytes of cattle, brush border and basolateral membranes, were studied. The activities were estimated under conditions of alkaline phosphatase activity inhibition by theophylline to exclude the nonspecific hydrolysis of ATP as well as to establish the orientation of vesicles with the use of alamethicine. 98% of the Na,K-ATPase activity (0.99 +/- 0.031 mumol/mg protein/min) was found to be localized in basolateral membranes. Both the brush border and basolateral membranes were found to possess the Ca,Mg-ATPase (0.193 +/- 0.018 and 0.795 +/- 0.025 mumol/mg protein/min) and Mg-ATPase (0.22 +/- 0.013 and 0.403 +/- 0.022 mumol.mg protein/min) activities.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Electrolyte composition of cow and calf tissues in health and in acute digestive disturbances].

Sodium, potassium, calcium, magnesium, manganese, zinc and chloride contents in the blood plasma of calves at parturition have been established to correspond to their levels in blood of cows during their calving period. Iron and inorganic phosphorus contents in calves blood plasma appeared to increase and copper content to be lower in this period as compared to postnatal period. By the third day of postnatal ontogenesis sodium concentration in calves blood decreased, copper level increased and the rest indices of water-salts metabolism in calves and adult animals were alike. Digestion disturbances in the calves were accompanied by changes in levels and magnitude of Na+/K+ ratio, magnesium, iron, copper, manganese and zinc contents in blood, liver and kidneys as well as Ca++/Pi ratio in mitochondria and cytosol of liver and jejunum mucose layer cells in comparison with clinically healthy animals.

Acute Disease↗
PubMedDate not supplied

[The characteristics of nitrogen metabolism in the tissues of rabbits with ammonium toxicosis].

Disturbances of nitrogen metabolism under acute ammonium toxicosis have been studied in tissues of rabbit. A sharp increase of the ammonium content in the blood and tissues of the liver and kidneys is accompanied by an increase in the glutamine and glutamate level in all tissues. The level of urea nitrogen in the blood of rabbits increases. The activity of phosphate-independent and phosphate-activated glutaminase also increases in tissues of the liver and kidneys, while arginase activity decreases as compared with the control, which is connected with fall of the ATP level under hyperammonemia. A nomograph method of representation of the redox state has been used.

Ammonia↗
PubMedDate not supplied

[Acid-base status of the blood and adenine nucleotide metabolism in ruminant erythrocytes during early post-natal development].

It has been established that data of acid-base balance in cows' and newborn calves' blood closely correlate with physiological status of animals during their initial days of postnatal ontogenesis and depend on the peculiarities of metabolism in fetus and newborn organisms. Data on the acid-base balance in blood of newborn calves under diarrhea syndrome are discussed from the point of view of the influence of rehydration therapy and "Namacit" preparation on clinical status of animals.

Acidosis↗
PubMedDate not supplied

[Lipid composition of plasma membranes of jejunum enterocytes in cattle of different age].

The lipid composition of plasma membranes (a brush margin and basolateral membranes) of enterocytes from the jejunum of cattle: adult animals (aged 1.5-3) and newborns (3-5 days) both healthy and suffering from diarrhea has been studied. Substantial differences are established in the content of phospholipids, cholesterol and fatty acids in the brush margin and basolateral membranes as well as in the both membrane fractions of the adult, newborn and sick animals.

Aging↗
PubMedDate not supplied

[Changes in the activity of alkaline phosphatase and Na K ATPase in the membrane fractions of small-intestinal epithelium in the normal state and in diarrhea].

Activity of alkaline phosphatase (apical membrane) and Na+, K+-ATPase (basal membrane) is determined to decrease in the membrane fractions of intestinal epithelium in the diarrheic new born cattle. It is concluded that Na+, K+-ATPase of basal membranes play a fundamental role in Na+ loss by body with diarrhea.

Alkaline Phosphatase↗
PubMedDate not supplied

[Impairment of energy metabolism in rabbit tissues during ammonia toxicosis].

The studies are conducted on the model of grave toxicosis in vivo in rabbits. It is shown that an increase in the ammonia content in blood and tissues enhances the content of lactate, glutamate, oxaloacetate in the liver and kidneys of animals, decreases the level of pyruvate, alpha-ketoglutarate and malate in the liver tissue. The NAD+/NADH ratio in the cytoplasm of the liver and kidney cells decreases, the ratio of NADP-pairs in the cytoplasm and mitochondria of these tissues noticeably increases. The energy metabolism is disturbed sharply, the content of adenosine phosphates lowers.

Adenine Nucleotides↗
PubMedDate not supplied

[Metabolic system of acid-base homeostasis in the human and animal body].

Peculiarities of carbohydrate, lipid, amino acid nucleotide metabolism, of the tricarboxylic acid cycle functioning and of the oxidative phosphorylation have been studied in man and animals under conditions of changes in the acid-base equilibrium (ABE) state in the organism. The results of studies are analyzed and generalized. Strictly defined peculiarities of changes in the mentioned aspects of metabolism depending on the ABE state in the organism are revealed. Basing on a new interpretation of the experimental data and detected regularities in the metabolism, the author has drawn a conclusion on the existence of the previously unknown system of acid-base homeostasis in tissues. The physiological sense of this system functioning is the regulation of the intracellular acid-base equilibrium stability. The regulation mechanisms promoting functioning of this system are discussed. The system is shown to be of great applied significance for improvement of methods to cure a number of human and animal diseases as well as for an increase of the productivity of animals.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Isolation, purification and characteristics of brush border and basolateral membranes from cattle intestinal epithelium cells].

The surface membrane of cattle intestine epithelium cells is separated into vesicated membrane fractions of the brush border and of basolateral membranes. The brush border membrane fraction is deposited with centrifugation (15,000 g) and is localized in the layers of 45, 56.5 and 48% in the density gradient of sucrose (105,000 g). Basolateral membranes, obtained at 70,000 g, in the density gradient of sucrose are in the layers of 30 and 31.5%. The brush border membranes are 8.5 times purified, basolateral membranes--9.1 times with their insignificant contamination with subcellular elements. The both fractions are deprived of mitochondria impurities.

Animals↗
PubMedDate not supplied

[A new method correcting metabolic acidosis].

A new method is suggested for correction of metabolic acidosis. The method consists in a decrease of pH of the bicarbonate sodium solution used for intravenous injection down to the physiological value of pH in the blood at the expense of buffering the solution by CO2. Experimental data conforming the efficiency of the new method application are presented.

Acidosis↗
PubMedDate not supplied

[Characteristics of nitrogen metabolism in chickens with gout].

It is shown that the intensity of ammonium genesis, purines biosynthesis and redox processes increases in the organism of chicken with visceral gout. Sodium bicarbonate-correction of the acid-alkaline state of chickens is performed in order to normalize disturbances observed under gout.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Changes in the levels of various substrates of nitrogen metabolism and tricarboxylic acid cycle during experimental acidosis in calves].

The effect of experimental metabolic acidosis and its correction for nitrogen and energy metabolism was studied in new-born calves. It was discovered that a change in the acid-base balance towards acidosis causes a sharp increase in "ammoniogenesis", urea formation and inhibition of the tricarboxylic acid cycle, which is also observed in calves suffering from dyspepsia with symptoms of acute diarrhea. Alongside with the use of therapeutic measures for treating dyspepsia of new-born calves, it is necessary to control the acid-base balance of blood in the calves and in case of revealing the acidosis state to use means of its correction.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Seasonal changes in the levels of various metabolites and proteins in cow milk and colostrum].

The studies on lactating black-and-white cows have shown that the content of albumins as well as of lactate, ammonia and glutamate in colostrum and milk of cows is higher in winter and spring but the level of beta- and gamma-globulins, citrate and urea is lower than the analogous indices in cows in summer. The concentration of alpha-globulins, oxaloacetate, malate and pyruvate in colostrum and milk did not change with the season.

Animals↗
PubMedDate not supplied

[Effect of carbonic acid on glutamate dehydrogenase interaction with NADH].

The method of fluorescent titration was used to study the effect of carbonic acid on the process of NADH binding with the purified preparation of glutamate dehydrogenase as well as on fluorescent properties of the above mentioned coenzyme. It is shown that in bicarbonate buffer at the alkaline values of pH there is a decrease in the maximal capacity of the binding sites of the enzyme with low affinity to co-enzyme. The capacity of high-affinity binding sites in this case is unchanged. It is found that pCO2, HCO3- and H+ exert an effect on the dissociation constants of the NADH-glutamate dehydrogenase complex as well as on fluorescent properties of bound NADH. It is supposed that the effects observed are a result of the interaction of dissolved carbon dioxide with free amino groups of protein molecule.

Animals↗