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Biomedical subjects

E G Vetrova

Publications and source records attributed to E G Vetrova.

At least 19 recordsLinked to original sources
PubMed1997

[Lipid peroxidation and activity of diagnostically significant enzymes in cosmonauts after flights of various durations].

Concentrations of the products of peroxide oxidation of lipids (POL), indices of the system of antioxidant defence (SAD), and the activity of 13 diagnostically significant organic/tissue specific enzymes (DSE) were determined in blood serum of cosmonauts who had participated in short (5-9 days, n = 8), long (125-179 days, N = 15), and superlong (241-366 days, n = 5) missions. To feature an interrelation of the indices under study, the canonical correlation analysis of a set of POL and SAP parameters and DSE activity was performed. Compared with pre-flight values, changes in the POL and SAP parameters were significant in serum only after the long-duration missions. Signs of POL activation were noted following the superlong missions. After the long-duration missions increased was the activity (mainly, within the norm) of DSEs, specific for the organs and tissues functioning of which is stressed in the period of post-flight readaptation (skeletal muscles, myocardium, liver). After the superlong missions, the DSE activity either remained essentially unchanged or decreased. In all the tested groups, highly reliable correlations between POL, SAP, and the DSE activity, traditionally applied in clinical diagnostics, were observed. These advocate for the use of POL and SAP indices in medical diagnostics and prognosis of cosmonauts' health.

Acid Phosphatase↗
PubMed1996

Energy substrates, hormone responses and glucocorticoid binding in lymphocytes during intense physical exercise in humans following phosphocreatine administration.

Eight healthy untrained male volunteers pedalled a cycle ergometer according to two exercise protocols: the first involved step-wise increasing physical exercise to maximal (MPE); the second involved prolonged (35 min) submaximal physical exercise (PPE) at 70% of the individual's maximal oxygen uptake. Each volunteer performed these exercise twice, following either an intravenous injection of phosphocreatine (PCr) or a placebo of an isotonic NaCl solution. Anaerobic threshold (AT) was determined from the point of departure of the ventilatory response from linearity and from the sudden increase in venous blood lactate concentrations during MPE. After exercise following placebo administration we observed increases in concentrations of blood substrates, plasma adrenocorticotropin (ACTH), growth hormone and cortisol and in the number of glucocorticoid receptors in lymphocytes without changes in the dissociation constant. Intravenous administration of PCr (starting 1 day before exercise) led to an increase in the total workload (on average by 5.8%) and in AT (on average by 6.8%) during MPE and to a better tolerance of exercise during PPE. Following PCr administration we observed lower blood lactate concentrations and different patterns of some enzyme activities, less pronounced changes in plasma ACTH and cortisol concentrations and in glucocorticoid binding in lymphocytes, but no changes in plasma growth hormone concentrations compared to the placebo. The results showed that intense physical exercise led not only to increases in blood hormone concentrations but also to an increase in the density of glucocorticoid receptors in lymphocytes. Intravenous PCr injection led to smaller changes in ACTH and cortisol concentrations as well as to a lower activation of glucocorticoid binding in lymphocytes.

Adrenocorticotropic Hormone↗
PubMed1994

[Effects of a long-term space flight on human biochemical status].

Biochemical status of cosmonauts was examined during long (4-6 months) space flights. A Reflotron device and test strips with an active principle based on "dry chemistry" methods were used. Blood plasma samples were collected from the finger for later laboratory analyses. Parameters characterizing metabolic status and functions of various body systems and organs were tested in blood and plasma samples. Space flight was found associated with increased peripheral blood levels of glucose, cholesterol, triglycerides, urea, uric acid, lactate, total protein, lactate dehydrogenase and amylase activities. The detected shifts were reversible. A hypothesis on minimal levels of energy metabolism under conditions of weightlessness was confirmed by reduced malate dehydrogenase and creatine phosphokinase activities in the blood during the flights. No correlation between the detected shifts and space flight duration was revealed.

Blood↗
PubMed1976

[Mitochondrial thymidine kinase and ribonucleotide reductase from rat liver and rat hepatoma 27].

Fractions of heavy and light mitochondria are isolated from homogenates of homologous rat tissues (intact liver, regenerating liver within 24 hours after hepatectomy and 27 hepatoma) by means of differential centrifugation. It is found that tumour mitochondria have higher heterogeneity and lower buyoant density than mitochondria from normal hepatocytes. The activity of two enzymes of DNA precursors synthesis (ribonucleotide reductase and thymidine kinase) in subcellular fractions is demonstrated to correlate with the tissue growth rate. A single injection of cyclic AMP into hepatectomised rats resulted in the retardation of the regeneration process, and the activity of both enzymes reached its normal level in all the fractions studied after 24 hours after the operation. Thymidine kinase and ribonucleotide reductase are located mainly in the mitochondrial matrix, however, pronounced enzyme activity is observed also in membrane fractions. The activity of the enzymes in the fraction of external mitochondria membranes in rapidly growing tissues is 2--3 times as high as in the same fraction from normal rat liver.

Animals↗
PubMedDate not supplied

[Human blood biochemical parameters under the conditions of an arid zone].

Seven participants of 23 day walking march in an arid environment have been examined. Biochemical analysis of blood serum made on Day 2 of marching revealed a decrease in the levels of glucose, triglycerides and an increase in the concentration of non-esterified fatty acids which the authors characterize as the state of moderate stress in an acute period.

Adaptation, Physiological↗
PubMedDate not supplied

[Metabolism in cosmonauts: the results of biochemical research on the blood of the crew members of the 7 prime expeditions on the Mir orbital space complex].

The pre- and postflight biochemical analyses of the blood of 16 cosmonauts flown aboard Mir orbital station over 125-366 days revealed the changes in carbohydrate, lipid and protein metabolism being in line with the present-day ideas about the space flight effects on the human metabolism. A particular individual pattern of the responses and the absence of correlation with flight duration of space expeditions ranging from 4 months to a 1 year, are noted.

Blood↗
PubMedDate not supplied

[Carbohydrate and lipid metabolites and blood serum enzymes in humans during graded exercise test in long-term anti-orthostatic hypokinesia].

Exercise tests were carried out before as well as on days 128 and 248 of a 370-day head-down tilt study. The test subjects, who took part in the study, were divided into two groups that used different regimens of countermeasures (drugs and exercise). During exercise tests the following serum parameters were measured: lactate, pyruvate, glucose, triglycerides, nonesterified fatty acids, lactate dehydrogenase, alpha-hydroxybutyrate dehydrogenase, malate dehydrogenase, creatine phosphokinase. Decrease or delayed increase in the concentration of energy substrates (nonesterified fatty acids and triglycerides) after a standard exercise test is a metabolic manifestation of deconditioning changes induced by head-down tilting. Insufficient supply of a working human body with readily utilizable lipid substrates causes inadequate activation of energy forming enzymes and excessive buildup of metabolites, i. e. lactate and pyruvate. The efficacy of corrective and prophylactic measures was verified by biochemical data.

Alcohol Oxidoreductases↗
PubMedDate not supplied

[Correlations of cardiorespiratory and metabolic reactions in humans with graded physical load].

Bicycle ergometry tests of graded workloads were performed by 9 healthy men, aged 25 to 40 years. During the tests cardiorespiratory parameters, lactate and pyruvate concentrations, as well as lactate dehydrogenase (LDH) and NADP-dependent isocitrate dehydrogenase (ICDH) activities were measured. It was shown that the threshold of anaerobic metabolism can be measured not only by traditional methods (with respect to variations in pulmonary ventilation and venous blood lactate) but also in terms of ICDH increase as a function of the workload. Mathematical processing of the resulting data did not reveal a correlation between the total oxygen debt and lactate in blood. In contrast, a close correlation between the debt and LDH activity at the end of the test was found. These observations have demonstrated that biochemical measurements should find a wider application in evaluations of energy costs of various workloads.

Adult↗
PubMedDate not supplied

[The effect of prolonged antiorthostatic hypokinesia on the blood serum activity of enzymes involved in energy and plastic metabolism].

In the course of 370-day antiorthostatic (-5 degrees) hypokinesia in which 9 test subjects participated the following changes in serum enzymes associated with energy metabolism inhibition were recorded: decreases of creatine phosphokinase (CPK) at the expense of its MM-isoform, isocitrate and glutamate dehydrogenases as well as increases of alanine and aspartate aminotransferases, gamma-glutamyl transferase, and lactate dehydrogenase (LDH) at the expense of an increased portion of its aerobic H-isoforms. During the recovery period these parameters returned to the norm. The counter-measures used (drugs combined with exercise) exerted a beneficial effect only in relation to CPK, gamma-glutamyl transferase and aspartate aminotransferase.

Alanine Transaminase↗
PubMedDate not supplied

[Effect of clinostatic and anti-orthostatic hypokinesia on serum enzyme activity].

Seven-day exposure to clinostatic and antiorthostatic hypokinesia led to a significant decrease of Krebs cycle enxymes (malate dehydrogenase--MDH and isocitrate dehydrogenase) and creatine phosphokinase with no significant changes in lactate dehydrogenase (LDH), aspartate aminotransferase, alanine aminotransferase and MDH and LDH isoenzymes. This hypofermentemia returned to normal during 7-day readaptation. It was not associated with hemodynamic changes or emotional stress. The hypofermentemia was adaptive and induced by diminished motor activity.

Creatine Kinase↗
PubMedDate not supplied

[Homeostatic reactions of the blood of experimental rats after "Kosmos-1667" flight].

Biochemical analysis of blood of rats sacrificed 4 to 8 hours after Cosmos-1667 flight revealed a significant increase of corticosterone, decrease of 11-dehydroxycortisol, testosterone, total and bound thyroxine, and increase of glucose, phosphate, creatinine, alanine aminotransferase and total antioxidative activity. Changes in hormonal concentrations, glucose content and stimulation of antioxidant defense system were associated with a moderate gravitational stress. Increases in the creatinine and inorganic phosphate concentrations can be viewed as specific effects of microgravity related to musculo-skeletal or fluid-electrolyte changes.

Animals↗
PubMedDate not supplied

[Dehydrogenase activity of the liver in rats following 30 days' exposure to hypergravity].

In response to 30-day centrifugation at 2.0 or 1.1 G rats showed decreases in liver mitochondrial and cytoplasmic NAD-dependent malate dehydrogenase and NADH-dependent isocitrate dehydrogenase. These changes can be considered as a decline of energetic and biosynthetic processes in the liver in response to hypodynamics and hypergravity. After cessation of centrifugation the liver enzymes returned to the pretest level: cytoplasmatic dehydrogenases on the 2nd day and mitochondrial malate dehydrogenase on the 7th day of recovery.

Animals↗
PubMedDate not supplied

[Metabolic characteristics during 120-day head-down tilt hypokinesia].

Nine healthy test subjects, aged 25 to 44 years, were exposed to bed rest (at -5 degrees) for 120 days. Venous blood and 24-hour urine samples were used to measure Na, K, total and ionized Ca, Mg, total protein, protein fractions, creatinine, urea, uric acid, malate, isocitric and lactate dehydrogenases, aspartate and alanine aminotransferases, and creatine phosphokinase and its isoforms, acid and alkaline phosphatase and its isoenzymes. Prolonged exposure to head-down tilting resulted in a negative balance of fluid and electrolytes, lowered concentration of total protein and albumins, and an increased concentration of urea and creatinine, basic products of protein metabolism. In blood, the activity of dehydrogenases of the tricarboxylic acid cycle and creatine kinase decreased at the expense of its muscle isoenzyme and the activity of acid phosphatase, total alkaline phosphatase and bone isoenzyme of alkaline phosphatase increased.

Adult↗
PubMedDate not supplied

[Activity of oxidative enzymes during dosed exercise in healthy persons and in persons with neurocirculatory dystonia].

In response to controlled exercise (50% and 75% of maximum workload) malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICDH) varied similarly in healthy men and in patients with hypertensive and hypotensive type neurocirculatory dystonia. However, in neurocirculatory dystonia subjects MDH increase during exercise and normalization during recovery developed slower than in healthy people. The MDH distribution between mitochondrial and cytoplasmic fractions remained unchanged.

Aerospace Medicine↗