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Biomedical subjects

I A Popova

Publications and source records attributed to I A Popova.

At least 19 recordsLinked to original sources
PubMed1992

Analyses of plasma for metabolic and hormonal changes in rats flown aboard COSMOS 2044.

Plasma samples from rats flown aboard COS-MOS 2044 were analyzed for the levels of key metabolites, electrolytes, enzymes, and hormones. The major differences between the flight group and the synchronous control were elevations in glucose, cholesterol, phosphate, creatinine, blood urea nitrogen, lactate dehydrogenase, and aspartate amino-transferase and decreased levels of thyroxine. Most of these differences were not mimicked by tail suspension of ground-based rats; however, both flight and suspended rats exhibited inhibited testosterone secretion. Corticosterone, immunoreactive growth hormone, and prolactin showed inconsistent differences from the various control groups, suggesting that the levels of these hormones were not due to actual or simulated microgravity.

Adrenal Glands↗
PubMed1992

Differences in glycogen, lipids, and enzymes in livers from rats flown on COSMOS 2044.

Livers from rats flown aboard COSMOS 2044 were analyzed for protein, carbohydrate (glycogen), and lipids as well as the activities of a number of key enzymes involved in metabolism of these compounds and xenobiotics. The major differences between the flight group and the synchronous control were elevations in microsomal protein, liver glycogen content, tyrosine aminotransferase, and tryptophan oxygenase and reductions in sphingolipids and the rate-limiting enzyme of heme biosynthesis, delta-aminolevulinic acid synthase. These results provide further evidence that spaceflight has pronounced and diverse effects on liver function; however, some of the results with samples from COSMOS 2044 differed notably from those from previous spaceflights. This may be due to conditions of spaceflight and/or the postflight recovery period for COSMOS 2044.

Amino Acids↗
PubMed1992

Circulating parathyroid hormone and calcitonin in rats after spaceflight.

Parathyroid hormone and calcitonin, two major calcium-regulating hormones, were measured in the plasma of five experimental groups of rats to evaluate postflight calcium homeostasis after the 14-day COSMOS 2044 flight. Parathyroid hormone values were slightly higher in the flight animals (F) than in the appropriate cage and diet controls (S) (44 +/- 21 vs. 21 +/- 4 pg/ml, P less than 0.05), but they were the same as in the vivarium controls (V), which had different housing and feeding schedules. Neither V nor S showed the increase in plasma creatinine phosphorus and magnesium found in F, features of early renal insufficiency. F showed the lowest mean plasma calcitonin that was statistically different from V only. This difference in F and V (22 +/- 11 vs. 49 +/- 16 pg/ml, P less than 0.05) was most likely due to failure of circulating calcitonin in F to show the normal age-dependent increase we demonstrated in age-matched controls in a separate experiment. Basal values for parathyroid hormone and calcitonin were unchanged after 2 wk of hindlimb suspension, a flight simulation model, in age-matched and younger rats. From a time course experiment serum calcium was higher and parathyroid hormone lower after 4 wk than in ambulatory controls. Postflight circulating levels of parathyroid hormone appear to reflect disturbances in calcium homeostasis from impaired renal function of undetermined cause, whereas levels of calcitonin reflect depression of a normal growth process.

Adrenal Glands↗
PubMed1991

Cyclic AMP-receptor proteins in heart muscle of rats flown on Cosmos 1887.

A frequent cellular response to organismal stress is the increase in ligand binding by beta-adrenergic receptors. The extracellular signal is amplified by intracellular increases in cyclic AMP and the ensuing activation of cyclic AMP-dependent protein kinase (cAPK). The molecular mechanisms involve the binding of cyclic AMP to regulatory (R) subunits of cAPK, thus freeing the catalytic subunit for protein phosphorylation. This study was carried out to determine the cellular compartmentalization of the cyclic AMP-receptor proteins in heart ventricular tissue obtained from rats flown on the Cosmos 1887 mission. Photoaffinity labeling of soluble and particulate cell fractions with an [32P]-8-azido analog of cyclic AMP was followed by electrophoretic separation of the proteins and by autoradiographic identification of the labeled isoforms of cAPK R subunits. The results showed that RII in the particulate subcellular fraction was significantly decreased in heart cells from rats in the flight group when compared to controls. Protein banding patterns in both the cytoplasmic fraction and in a fraction enriched in chromatin-bound proteins showed some variability in tissues of individual animals, but exhibited no changes that could be directly attributed to flight conditions. No significant change was apparent in the distribution of RI or RII cyclic AMP binding in the soluble fractions. These findings indicate that the cardiac cell integrity or its protein content is not compromised under flight conditions. There is, however, what appears to be an adaptive molecular response which can be detected using microanalytical methods, indicating that a major hormone regulated mechanism may be affected during some phase of travel in space.

Animals↗
PubMed1990

Cosmos 1887 mission overview: effects of microgravity on rat body and adrenal weights and plasma constituents.

The Cosmos 1887 biosatellite carried 10 male rats and 2 rhesus monkeys on its 12.5-day mission. Upon re-entry the Vostok vehicle overshot the designated landing site, which resulted in fasting of the animals for 42 h, exposure to cage temperatures of 12-15 degrees C, and 2 days delay in death of the rats. No overt untoward effects of the delayed recovery were apparent. Tissues from the rats were harvested by Soviet scientists, appropriately preserved, and provided to U.S. investigators. Flight rats grew more slowly and had larger adrenal glands than earth gravity controls. Analysis of plasma revealed increased concentrations of hepatic alkaline phosphatase, glucose, urea nitrogen, and creatinine in flight rats. In contrast, electrolytes, total protein, albumin, corticosterone, prolactin, and immunoreactive growth hormone levels were unchanged. However, testosterone concentration was marginally decreased after flight and thyroid hormone levels were suggestive of reduced thyroid function. Due to the possible effects of reentry and the delay in recovery of the animals, it is not clear what relationship postflight levels of plasma constituents bear to their concentrations in flight.

Adrenal Glands↗
PubMed1990

Morphological and biochemical examination of Cosmos 1887 rat heart tissue: Part I--Ultrastructure.

Morphological changes were observed in the left ventricle of rat heart tissue from animals flown on the Cosmos 1887 biosatellite for 12.5 days. These tissues were compared to the synchronous and vivarium control hearts. While many normal myofibrils were observed, others exhibited ultrastructural alterations, i.e., damaged and irregular-shaped mitochondria and generalized myofibrillar edema. Analysis of variance (ANOVA) of the volume density data revealed a statistically significant increase in glycogen and a significant decrease in mitochondria compared to the synchronous and vivarium controls. Point counting indicated an increase in lipid and myeloid bodies and a decrease in microtubules, but these changes were not statistically significant. In addition, the flight animals exhibited some patchy loss of protofibrils (actin and myosin filaments) and some abnormal supercontracted myofibrils that were not seen in the controls. This study was undertaken to gain insight into the mechanistic aspects of cardiac changes in both animals and human beings as a consequence of space travel (1). Cardiac hypotrophy and fluid shifts have been observed after actual or simulated weightlessness and raise concerns about the functioning of the heart and circulatory system during and after travel in space (2-4).

Actins↗
PubMed1990

Altered carbohydrate, lipid, and xenobiotic metabolism by liver from rats flown on Cosmos 1887.

To determine the possible biochemical effects of prolonged weightlessness on liver function, samples of liver from rats that had flown aboard Cosmos 1887 were analyzed for protein, glycogen, and lipids as well as the activities of a number of key enzymes involved in metabolism of these compounds and xenobiotics. Among the parameters measured, the major differences were elevations in the glycogen content and hydroxymethylglutaryl-CoA (HMG-CoA) reductase activities for the rats flown on Cosmos 1887 and decreases in the amount of microsomal cytochrome P-450 and the activities of aniline hydroxylase and ethylmorphine N-demethylase, cytochrome P-450-dependent enzymes. These results support the earlier finding of differences in these parameters and suggest that altered hepatic function could be important during spaceflight and/or the postflight recovery period.

Aniline Hydroxylase↗
PubMed1976

Some cases of Type III glycogen storage disease.

Five patients with glycogen storage disease are described. Hypoglycemia was observed in all patients after an overnight fast, and glycemic and lactatemic curves obtained after oral administration of glucose or galactose were typical of those seen in Type III glycogenosis. An increase of liver glycogen up to 12-16% and complete absence of liver amylo-1,6-glucosidase were found in liver tissue samples obtained by needle biopsy. The patients were diagnosed as having Type III glycogenosis. In two patients the absence of amylo-1,6-glycosidase was accompanied by a sharp decline of liver phosphorylase activity. In one patient a decline of glucose-6-phosphatase activity was observed. The structure of liver glycogen was different in different patients, and so were the types of glycemic and lactatemic curves obtained upon protein tolerance tests. The above phenomena might be explained by some secondary disturbances in the activity of enzymes (phosphorylase, glucose-6-phosphatase) involved in the metabolism of liver glycogen of these patients.

Blood Glucose↗
PubMed1976

[Serologic pattern of meningococci in a focus of infection].

The authors present the results of typing of meningococci (isolated from the patients and carriers) by the sera of serological groups A, B, C, D, X, Y, and Z made at the Leningrad Institute of Vaccine and Sera. The causative agents of serological group A were most frequently isolated from the patients with the generalized forms of meningococcus infection. The percentage of detection of meningococci of serological group A was the greatest in the patients and much less in the carriers in and outside the foci of this infection. Many dissociated cultures were revealed among the strains isolated from the carriers. Sera of the Leningrad Institute of Vaccine and Sera have permitted typing of meningococci cultures belonging to various serological groups in accordance with the international classification.

Humans↗
PubMed1975

[Differential traits and antigenic properties of the S- and R-forms of Neisseria meningitidis].

The authors demonstrated a marked dissociation of the Neisseria meningitis cultures and the capacity to their rapid change from S- to R-forms. Differential signs of the S- and R-forms are described. Differences in the degree of dissociation of the cultures depending on their origin were shown: strains isolated from the cerebrospinal fluid and the blood of patients with meningitis proved to be less dissociated, and those isolated from carriers--more dissociated. Transfers from media to media and adaptation of cultures to artificial nutrient media produced the greatest influence on dissociation of the freshly isolated strains.

Agglutination Tests↗
PubMedDate not supplied

[Glycogen breakdown in the tissue of human cerebral glial tumors].

The activity of gamma-amylase (acid alpha-glucosidase) and phosphorylase in the tissue of human glial tumours and the brain tissue adjacent to the tumour was studied. A sharp (more than three-fold) increase of the activity of gamma-amylase was found in the tissue of glial tumours. In the adjacent tissues of the brain its activity was also elevated (approximately, two-fold). The activity of phosphorylase is practically lacking in human glial tumours, and is only slightly apparent in the brain tissue neighbouring the tumour. Gamma-amylase may be suggested to play an important role in glycogen metabolism of glial tumours in man.

Amylases↗
PubMedDate not supplied

[Effect of noradrenaline and serotonin on glycogen metabolism in rat tissues].

Effects of biogenic amines--noradrenaline and serotonin--on phosphorylase, acid alpha-glucosidase (gamma-amilase), glycogen synthetase as well as on content of glycogen in rat liver tissue, heart and skeletal muscles were studied in vivo. Administration of noradrenaline and serotonin led to activation of phosphorylase in liver tissue, heart and skeletal muscles. Noradrenaline, administered into rats, caused a decrease in activity of acid alpha-glucosidase in heart and liver tissues and did not affect the enzymatic activity in skeletal muscles. Serotonin did not cause any effect on the activity of acid alpha-glucosidase in all the tissues studied. After administration of both amines inhibition of glycogen synthetase occurred in heart muscle, whereas the enzymatic activity was unaltered in skeletal muscles and liver tissue. Content of glycogen was decreased in heart muscle of the rats in which noradrenaline was administered. Content of glycogen was increased after serotonin administration in similar experiments. In liver tissue both amines caused a decrease in glycogen concentration and did not affect its content in skeletal muscles. Possible interrelationship is discussed between phosphorolysis and hydrolysis of glycogen under conditions of myocardial hypoxia, caused by noradrenaline administration.

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

[The effect of space flight on metabolism: the results of biochemical research in rat experiments on the Kosmos biosatellites].

Cosmos biosatellites research program was the unique possibility to study the metabolic features influenced by space flight factors. Based on the existing ideas about relationships between some metabolic responses, the state of metabolism and the systems of its control in the rats flown in space was evaluated to differentiate the processes occurred in microgravity, possibly under effect of this factor and during first postflight hours. The biochemical results of studying the rats exposed to space environments during 7, 14, 18.5 and 19.5 days and sacrificed 4-11 h after landing (Cosmos-782, -936, -1129, -1667, -2044 flight) are used. The major portion of data are in line with understanding that after landing when the microgravity-adapted rats again return to 1-g environments they display an acute stress reaction. A postflight stress reaction is manifested itself in a specific way as compared to adequate and well studied model of acute and chronic stress and dictates subsequent metabolic changes. Postflight together with the acute stressful and progressing readaptation shifts the metabolic signs of previous adaptation to microgravity are shown up. In the absence of engineering feasibility to control or record the state of metabolism inflight it can only presupposed what metabolic status is typical of the animals in space environments and that its development is triggered by a decreased secretion of the biologically active growth hormone. This concept is confirmed by the postflight data.

Adaptation, Physiological↗