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Biomedical subjects

M Viso

Publications and source records attributed to M Viso.

At least 19 recordsLinked to original sources
PubMed2005

Checkpoint and physiological apoptosis in germ cells proceeds normally in spaceflown Caenorhabditis elegans.

It is important for human life in space to study the effects of environmental factors during spaceflight on a number of physiological phenomena. Apoptosis plays important roles in development and tissue homeostasis in metazoans. In this study, we have analyzed apoptotic activity in germ cells of the nematode C. elegans, following spaceflight. Comparison of the number of cell corpses in wild type or ced-1 mutants, grown under either ground or spaceflight conditions, showed that both pachytene-checkpoint apoptosis and physiological apoptosis in germ cells occurred normally under spaceflight conditions. In addition, the expression levels of the checkpoint and apoptosis related genes are comparable between spaceflight and ground conditions. This is the first report documenting the occurrence of checkpoint apoptosis in the space environment and suggests that metazoans, including humans, would be able to eliminate cells that have failed to repair DNA lesions introduced by cosmic radiation during spaceflight.

Animals↗
PubMed2000

Variations in digestive physiology of rats after short duration flights aboard the US space shuttle.

The purpose of this work was to assess the influence of microgravity on several endogenous and microbial parameters of digestive physiology. On the occasion of two Spacelab Life Sciences missions, SLS-1 (a 9-day space flight) and SLS-2 (a 14-day space flight), Sprague-Dawley rats flown aboard the US space shuttle were compared to age-matched ground-based controls. In both flights, exposure to microgravity modified cecal fermentation: concentration and profile of short-chain fatty acids were altered, whereas urea and ammonia remained unchanged. Only in SLS-1 was there an induction of intestinal glutathione-S-transferase. Additional analyses in SLS-2 showed a decrease of hepatic CYP450 and of colonic goblet cells containing neutral mucin. After a postflight recovery period equal to the mission length, only modifications of the hepatic and intestinal xenobiotic metabolizing enzymes still persisted. These findings should help to predict the alterations of digestive physiology and detoxification potential likely to occur in astronauts. Their possible influence on health is discussed.

Animals↗
PubMed2000

Bion 11 science objectives and results.

The results from the Bion 11 mission were the most comprehensive set of data ever collected on primate physiology and behavior before, during, and after spaceflight. An international team of scientists representing neuromuscular and behavioral, neurosensory, regulatory, and bone physiology disciplines conducted a wide range of studies, which are briefly summarized herein. New insights were obtained, which can be expected to lead to new, efficient countermeasures for space-related changes, thereby facilitating long-duration human space voyages and providing additional assurance of human health and performance. These data will likely benefit medical areas on Earth that have overlap with challenges in space biology and medicine.

Adaptation, Physiological↗
PubMed2000

Bion 11 mission: primate experiments.

A summary is provided of the major operations required to conduct the wide range of primate experiments on the Bion 11 mission, which flew for 14 days beginning December 24, 1996. Information is given on preflight preparations, including flight candidate selection and training; attachment and implantation of bioinstrumentation; flight and ground experiment designs; onboard life support and test systems; ground and flight health monitoring; flight monkey selection and transport to the launch site; inflight procedures and data collection; postflight examinations and experiments; and assessment of results.

Adaptation, Physiological↗
PubMed1999

Biochemical characteristics of beta-adrenoceptors in rats after an 18-day spaceflight (LMS-STS78).

BACKGROUND: To ascertain whether there was autonomic adaptation with the development of adrenoceptor hypersensitivity under microgravity, the biochemical properties of the beta-adrenoceptors were determined using (125I)iodocyanopindolol (ICYP) binding in rats flown for 18 d onboard the space shuttle. METHODS: This study was performed on heart and kidneys of 3 groups of 12 animals: the flight and 2 ground control (vivarium and AEM) groups. To distinguish the possible role of the corticosteroids, half of each animal group was bilaterally adrenalectomized (ADX rats) with an aldosterone and corticosterone supplementation while the other half was SHAM operated. RESULTS: The Scatchard analysis of the ICYP-binding in both organs revealed no significant alterations in the dissociation constant (Kd) and in the maximal binding capacity (Bmax) between SHAM flight and control groups. The Kd of the beta-adrenoceptors in the cardiac atria of the SHAM flight rats (74 +/- 5 pm) was significantly higher (p < 0.05) than in those of the ADX flight rats (60 +/- 3 pm) while the Bmax was nonsignificantly higher (1925 +/- 370 in SHAM flight rats vs. 1482 +/- 283 fmol x mg(-1) protein in ADX flight rats). No significant change was determined for the Bmax and Kd values in the kidneys of the ADX and SHAM flight rats. CONCLUSIONS: This work performed on animals did not show any obvious effect of microgravity on the beta-adrenergic function in the heart and kidneys. Inflight rodent sacrifice protocols should definitely ensure assessment of the influence of microgravity on the animals.

Adaptation, Physiological↗
PubMed1998

Dosimetry during the first IBIS facility flight.

The dosimetry of cosmic rays was performed during the first experimental flight of the IBIS facility. Different thermoluminescent detectors (TLD) have been used to measure the contribution of the low linear energy transfer component (LET < 10 keV/micrometer) and plastic nuclear track detectors (PNTD) for the high linear energy tranfer (LET) component. Several parameters of tracks have been measured to determine the LET spectra of primary and secondary charged particles. The total absorbed dose rate (TLD+PNTD) during the flight was 0.23 mGy/day and the dose equivalent rate using the ICRP 60 was 0.52 mSv/day. The corresponding mean quality factor was 2.4. These results are in agreement with those obtained aboard the MIR station with a tissue equivalent proportional counter.

Cosmic Radiation↗
PubMed1998

Choroidal readaptation to gravity in rats after spaceflight and head-down tilt.

To determine when choroidal structures were restored after readaptation to Earth gravity or orthostatic position, fine structure and protein distribution were studied in rat choroid plexus dissected either 6 h [Space Life Sciences-2 (SLS-2) experiments] or 2 days [National Institutes of Health-Rodent 1 (NIH-R1) experiments] after a spaceflight, or 6 h after head-down tilt (HDT) experiments. Apical alterations were noted in choroidal cells from SLS-2 and HDT animals, confirming that weightlessness impaired choroidal structures and functions. However, the presence of small apical microvilli and kinocilia and the absence of vesicle accumulations showed that the apical organization began to be restored rapidly after landing. Very enlarged apical microvilli appeared after 2 days on Earth, suggesting increased choroidal activity. However, as distributions of ezrin and carbonic anhydrase II remained altered in both flight and suspended animals after readaptation to Earth gravity, it was concluded that choroidal structures and functions were not completely restored, even after 2 days in Earth's gravity.

Adaptation, Physiological↗
PubMed1997

Effects of chair-restraint on gastrointestinal transit time and colonic fermentation in male rhesus monkey (Macaca mulatta).

The incidence of an 18 day chair-restraint on the digestive physiology of male rhesus monkey was investigated for space research purposes, comparing four trained restraint subjects with two vivarium controls. Chair-restraint induced a 2.5-fold acceleration of the gastrointestinal transit time, which persisted throughout the 7 day postrestraint period, and an increase of the fecal dry matter content, which mean value rose from 40.7% to 69.6%. Fecal pH remained unaltered throughout the experiment. Modifications of fermentative metabolites produced by the colonic microflora and excreted through the breath (hydrogen and methane) or in the feces (short chain fatty acids and ammonia) could not be reliably related to chair-restraint and probably involved side-stress factors. On the whole, alterations due to chair-restraint are shown to be different from those reported in the literature, following a modification of the dietary composition. These data may help to predict the alterations of digestive physiology likely to occur in immobilized human patients.

Ammonia↗
PubMed1996

Hormonal response to restraint in rhesus monkeys.

The purpose of this study was to characterize the hormonal responses to a restraining system in four adult male rhesus monkeys (Macaca mulatta) in preparation for a spaceflight project. After the monkeys were accustomed to food and water (Phase I), blood-volume-regulating hormones were measured during three phases: 10 days in a metabolic cage (Phase II), 16 days sitting in a restrained position in a specially designed metabolism chair (Phase III) and 10 days in metabolic cage (Phase IV). An increase of active renin (30%) and vasopressin (25%) was observed at the end of Phase III. A decrease of atrial natriuretic peptide (ANP), urodilatin, and sodium excretion occurred during the first days of Phase III. Catecholamines were unchanged. A dramatic increase (tenfold) in urinary excretion of growth hormone occurred during all of Phase III and at the beginning of Phase IV. These findings are similar to those found in man during isolation inactivity and during confinement stress.

Aldosterone↗
PubMed1996

Cosmos 2229 mission. Overview.

The Cosmos 2229 unmanned biosatellite was launched from the Plesetsk Cosmodrome in northern Russia on December 29, 1992. This was the 10th Russia-sponsored international mission dedicated to space biology and marked the 8th mission with United States participation. The payload, which orbited the Earth for 11 days 16 h, included two rhesus monkeys; the papers that follow report studies on these monkeys.

Adaptation, Physiological↗
PubMed1996

Central and peripheral noradrenergic responses to 14 days of spaceflight (SLS-2) or hindlimb suspension in rats.

INTRODUCTION: The purposes of this work were to assess the influence of microgravity on the central and peripheral noradrenergic activity to reevaluate SLS-1 mission findings and to compare it with that of simulated microgravity in rats. METHODS: The norepinephrine (NE) contents of the brainstem cell groups (A1, A2, A5, and A6) and organs (heart and kidneys) involved in blood pressure regulation were determined in rats after a 14-d spaceflight (SLS-2 with animals sacrificed 6 h after landing) and after a 14-d hindlimb suspension followed with 6 h of recovery. RESULTS: After SLS-2 spaceflight, NE contents were not significantly different between flight and ground-based rats either in A1 (5.2 +/- 0.5 vs. 5.7 +/- 0.4 pmol/structure), rostral A2 (12.1 +/- 0.5 vs. 11.1 +/- 0.9 pmol/structure), caudal A2 (3.2 +/- 0.6 vs. 4.3 +/- 0.5 pmol/structure) and A5 (4.4 +/- 0.4 vs. 4.3 +/- 0.5 pmol/structure) nuclei or in cardiac atria (98.6 +/- 7.5 vs. 83.4 +/- 8.9 pmol.mg-1 protein), ventricles (38.3 +/- 2.2 vs. 44.1 +/- 2.8 pmol.mg-1 protein) and kidneys (13.4 +/- 0.8 vs. 17.7 +/- 1.5 pmol.mg-1 protein). NE content was unchanged in A6 nucleus after SLS-2 comparing with control rats (respectively 4.1 +/- 0.3 vs. 4.5 +/- 0.5 pmol/structure), while it was depleted after SLS-1 mission (2.9 +/- 0.3 vs. 8.8 +/- 0.7 pmol/structure, p < 0.001) probably in relation with the stressful conditions on return to Earth. Similarly, no alterations between suspended and control rats were noted in central and peripheral NE contents after 14 d of suspension and after 6 h of recovery, whereas NE turnover studies evidenced large changes in the activities on structures on suspension and on recovery. CONCLUSION: These results suggest that only NE turnover determination will provide information about the role of the sympathetic system in the cardiovascular deconditioning. This raises the problem of the necessity to experiment inflight (injections, sacrifice) in order to avoid the recovery effects of the few hours following the landing.

Animals↗
PubMed1995

A restraining system for rhesus monkeys used in space research.

A new chronic restraining system has been designed specifically for male rhesus monkeys (8-13 kg) housed in weightlessness for scientific purposes. The restraining system consists of a coat (jacket and skirt) and a chair. The system separates the thorax from the lower part of the body, and allows large movements of the upper part of the body. The macaque can feed and groom itself, and can also sleep in close-to-normal position.

Animals↗
PubMed1994

Comparison of the effects of spaceflight and hindlimb-suspension on rat pituitary vasopressin and brainstem norepinephrine content.

To compare actual spaceflight to ground-based simulation (hindlimb-suspension), we measured the norepinephrine (NE) content in A1, A2, A5 and A6 (locus coeruleus) and the vasopressin content in the neurohypophysial system. The experimental period was of 9 days' duration. The NE content in the locus coeruleus decreased significantly in rats flown for 9 days (67%, p < 0.001), but showed no significant changes after hindlimb-suspension. These results demonstrated that suspended rats adapted better to weightlessness-simulation than flown rats to actual microgravity. In rats flown aboard SLS-1, the vasopressin content was significantly increased in the posterior pituitary (71%, p < 0.01), and was decreased in the hypothalamus (49%, p < 0.05). In 9-day suspended rats pituitary vasopressin levels were unchanged, while in the hypothalamus a significant decrease was noted (21%, p < 0.05). It was concluded that spaceflight changes in pituitary vasopressin levels and in the locus coeruleus NE content were consistent with a stress reaction, occurring during and/or after landing. These results confirmed that hindlimb-suspension model constitutes a valid and less stressful [correction of lesstressful] ground-based simulation of microgravity in rats.

Animals↗
PubMed1994

ANP binding sites are increased in choroid plexus of SLS-1 rats after 9 days of spaceflight.

Specific alpha-rat 28-amino acid atrial natriuretic peptide [ANP(99-126)] (rANP) binding sites in choroid plexus and meningia of rats flown for 9 days on the mission STS-40 (SLS-1) carried on the space shuttle Columbia in June 1991 were analyzed after incubation of brain sections with 125I-rANP and autoradiography, using computer-assisted microdensitometric image analysis. The number of 125I-rANP binding sites (expressed by Bmax values) in the choroid plexus of lateral and third ventricles of these rats was significantly increased (x 1.5-2.5 times), as compared with that found in ground control rats. No differences in the binding affinity (deducible from Kd values) were observed at the level of these structures. The choroid plexus from the fourth ventricle of the same rats displayed no changes in the binding capacity or affinity after the spaceflight. Meningia from the rats flown in space did not demonstrate any significant modifications of the number of 125I-rANP binding sites, but displayed a significant increase in Kd values, which suggested a reduced affinity of the meningeal ANP receptors during a 9-d spaceflight. The possibility that atrial natriuretic peptide may be involved in the regulation of fluid and electrolyte fluxes in the brain, during adaptation to microgravity, through modified expression of specific high affinity receptors, mainly in choroid plexus from forebrain or in meningia, must be considered.

Animals↗
PubMed1993

Norepinephrine content in discrete brain areas and neurohypophysial vasopressin in rats after a 9-d spaceflight (SLS-1).

The norepinephrine (NE) content in discrete brain areas and the vasopressin content in the neurohypophysial system were assessed in rats after a 9-d spaceflight and after a recovery period (9 d). The NE content in the locus coeruleus decreased significantly in spaceflight rats (2.9 +/- 0.3 vs. 8.9 +/- 0.7 pmol.structure-1 for control rats, p < 0.001), but showed no difference between control and flight animals after a 9-d recovery. These findings were probably due to an acute stress undergone during landing. The NE content was unchanged in the A2 and A5 cell groups. In rats flown aboard SLS-1, the vasopressin content was increased in the posterior pituitary (1.47 +/- 0.1 vs. 0.86 +/- 0.1 micrograms.structure-1, for control rats, p < 0.01), and was significantly decreased in the hypothalamus (8.95 +/- 2.0 vs. 17.6 +/- 2.2 ng.structure-1, for control rats, p < 0.05). We conclude that the NE depletion in the locus coeruleus and the alteration in vasopressin release were consistent with an acute stress, likely occurring during and/or after landing. These changes tend to mask the actual neuroendocrine modifications caused by microgravity.

Animals↗
PubMed1990

An epidemiological study of winter dysentery in fifteen herds in France.

Winter dysentery is a highly contagious disease of cattle seen most often during the winter months. In the course of an epidemiological study, the management, production, hygiene and previous diseases in 15 herds were characterized by 32 variables. Each herd was then visited twice a week for 8 weeks and 8 to 10 cows were clinically examined during each visit. Winter dysentery occurred in half of the herds during the survey. All data were analysed by classical statistical methods and by multivariate analysis. Mild or severe disease provoked nasal discharge and was associated with significant economic loss. Winter dysentery outbreaks appeared to be associated with small farms in which the area available per cow is either too small or too large, the presence of coronavirus in the faeces and variations in the temperature of the stable and of the drinking water.

Animals↗
PubMed1988

[Immunomodulator effects of 2 antibiotics, chloramphenicol and kitasamycin, in the chicken].

One-day-old chickens treated via drinking water with kitasamycin (0.7 g/l for 6 days then 0.35 g/l for 15 days) or with chloramphenicol (1 g/l for 6 days the 0.5 g/l for 15 days), were immunized at the 24th day with sheep red blood cells. Body and spleen growths were recorded and compared to control every week for 5 weeks after immunization. Humoral and cell-mediated immune responses were measured by hemagglutinating antibodies titration, direct and indirect plaque forming cells (PFC) numeration, and graft versus host reaction (GVHR). Both antibiotics reduce antibody response and number of PFC, chloramphenicol being significantly more suppressive than kitasamycin. A short stimulation of cellular response is shown with kitasamycin, which stimulates GVHR, whereas chloramphenicol has a negative effect.

Animals↗