Biomedical subjects

V B Noskov

Publications and source records attributed to V B Noskov.

At least 19 recordsLinked to original sources

PubMed2006

[The influence of space flights on water-electrolytes turnover and its regulation].

A study of water-electrolyte exchange, the condition of water milieu of the organism, and the volume- and electrolyte homeostasis regulation in space flights, and also in postflight period has shown the important role of the water-salt homeostasis in adaptation of the human and animal organism to weightlessness. Obviously, downturn of food consumption, renal excretion and the intestine output seem to be caused by suppression of activity of mechanisms of ion deposition. The most intensive changes of the liquid milieu volumes occur in the first days of weightlessness or in its ground simulation. And, with prolonged duration, the changes of extracellular liquid volume and the volume of plasma do not extend. After termination of long space flights, activation of renin-aldosterone systems occurs as well as a decrease in efficiency of antidiuretic hormone, misbalance of pressor/unpressor prostanoids. In the period of re-adaptation after space flights, development of desensitization of kidneys to endogenous ADH occurs. This is the basis for researches directed to improvement of the existing scheme of correction of the hydrogenous status of the astronaut organism in the closing stage of flight.

Animals↗

PubMed2004

The G-tolerance after pharmacological hypohydration.

A group of 18 healthy male subjects (25-45 y.o.) participated in the studies of +8.3 Gx tolerance (profile of ballistic reentry) and +Gz tolerance (up to physiological limit) before and after pharmacological hypohydration of organism. Moderate hypohydration was carried out by one 40 mg Furosemid (Lasix) dose, or by pharmacological complex: Furosemid (40 mg) + Hypothiazide (25 mg) + Triamteren (50 mg). Subjects removed with urine about 2 l of water, that was accompanied by increase excretion of electrolytes and caused reduction of the body mass by 2.0 +/- 0.2% and diminution of the plasma volume by 13.5% +/- 2.0%. Pharmacological hypohydration does not lead to a substantial loss in +Gx tolerance. No pathological signs, limiting +Gx tolerance up to 8.3 g were found. The longitudinal +Gz tolerance was less, than +Gx one. The limit of achieved +Gz loads after diuretics reduced by 0.6 g. The scientific and applied significance of this research is that diuretics can be safety used in pre-launch period to prevent the negative effects associated with initial phase of space flight. Besides the preliminary intake of diuretics promotes to diminish of discomfort of cosmonauts, reducing urination in a period of prelaunch waiting in spacecraft.

Adaptation, Physiological↗

PubMed2004

Effect of space flight and head-down bedrest on neuroendocrine response to metabolic stress in physically trained subjects.

The aim of this study was to evaluate the association of plasma epinephrine (EPI) and norepinephrine (NE) responses to insulin induced hypoglycemia (ITT) 3 weeks before the space flight (SF), on the 5th day of SF, on the 2nd and 16th days after the landing in the first Slovak astronaut, and before and on the 5th day of prolonged subsequent head-down (-6 degrees) bed rest (BR) in 15 military aircraft pilots. Blood samples during the test were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transferred to Earth in special container for hormonal analysis. Insulin hypoglycemia was induced by i.v. administration of 0.1 IU/kg BW insulin (Actrapid HM) in bolus. Insulin administration led to a comparable hypoglycemia in pre-flight, in-flight conditions and before and after bed rest. ITT led to a pronounced increase in EPI levels and moderate increase in NE in pre-flight studies. However, an evidently reduced EPI response was found after insulin administration during SF and during BR. Thus, during the real microgravity in SF and simulated microgravity in BR, insulin-induced hypoglycemia activates the adrenomedullary system to less extent than at conditions of the Earth gravitation. Post-flight changes in EPI and NE levels did not significantly differ from those of pre-flight since SF was relatively short (8 days) and the readaptation to Earth gravitation was fast. It seems, that an increased blood flow in brain might be responsible for the reduced EPI response to insulin. Responses to ITT in physically fit subjects indicate the stimulus specificity of deconditioning effect of 5 days bed rest on stress response. Thus, the data indicate that catecholamine responses to ITT are reduced after exposure to real as well as simulated microgravity.

Adult↗

PubMed2003

The response of endocrine system to stress loads during space flight in human subject.

The responses of endocrine system to the exposure to stress-work load and hormonal changes during oral glucose tolerance tests were studied in the Slovak astronaut before (three weeks before flight), during (on the 4th and the 6th days of space flight), and after space flight (1-3 days and 15-17 days after space flight) on board of space station MIR. Blood samples during the tests were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transferred to Earth in special container for hormonal analysis. Preflight workload produced an increase of plasma norepinephrine and a moderate elevation of epinephrine levels. Plasma levels of insulin, growth hormone, prolactin and cortisol were not markedly changed immediately or 10 min after the end of work load. The higher increases of plasma growth hormone, prolactin and catecholamine levels were noted after workload during space flight as compared to preflight response. The higher plasma glucose and insulin levels were noted during the oral glucose tolerance test in space flight and also in the post flight period. Plasma epinephrine levels were slightly decreasing during glucose tolerance test; however, plasma norepinephrine levels were not changed. The similar patterns of catecholamine levels during glucose tolerance test were found when compared the preflight, in-flight and post flight values. These data demonstrate the changes of the dynamic responses of endocrine system to stress-work and metabolic loads during space flight in human subject.

Adaptation, Physiological↗

PubMed2003

[Correction of the human body hydration in different periods of space flight].

Hydration level of the human body at the end of space flight is not same as at its beginning. This was the reason for development and testing of opposite in action methods for hydration improvement: at the onset of microgravity a dehydration therapy is applied and, on the contrary, in the final period of space flight methods for retaining body fluids are of preference. Consumption of a diuretic and a water-salt supplement by orbiting crews reached the required effect suggesting applicability of the pharmaceutical correction as a measure against dehydration.

Dehydration↗

PubMed2003

[The water-salt balance and renal function in space flights and in model experiments].

Study of a condition of mineral and water-electrolyte metabolism, function of kidneys, and their hormonal regulation during model experiments (hypokinesia, bed rest, immersion etc.), and also in space flights and in readaptation period, has shown a major role of water-electrolyte homeostasis during general adaptation of humans and animals to new conditions of life and to conditions of weightlessness in particular. The change in regulation of volumes of fluid milieu in an initial period of weightlessness was shown to be the consequence of redistribution of blood and hemodynamics of the shifts resulting in change of production of volume-regulation hormones, formation of negative water balance, and redistribution of fluid in the organism among various fluid compartments. At later stages of flight or long-term hypokinesia, a change of water-electrolyte homeostasis occurs with a decrease in the kidneys excretion of sodium, and diuresis, but with an increased excretion of calcium and production of ADH and RAAS hormones. Following returning to earth gravitation, the majority of astronauts have adaptive reactions, compensating for the loss extracellular fluid and mineral substances and formation of "earth" water-electrolyte homeostasis. For estimation of water-electrolyte homeostasis and the functions of kidneys in astronauts, various functional loading tests have been developed. The developed system of preventive maintenance is successfully used for abolition of adverse changes at various stages of space flight and in readaptation period.

Astronauts↗

PubMed2003

[The effect of pharmacological hypohydration on g-tolerance].

A group of 6 subjects (25-45 y.o.) participated in the studies of the tolerance of lateral (chest-back, +Gx) and longitudinal (head-pelvis, +Gz) loads before and after pharmacological hypohydration. Moderate hypohydration (diminution of the circulating plasma volume by 14% and body mass by 2% on the average) induced by diuretics does not lead to a substantial loss in tolerance of +Gx up to 8.3 units but reduces the threshold of +Gz tolerance by 0.6 units. The scientific and applied sense of these data is that diuretics can be safely administered in the pre-launch period to prevent the negative effects associated with the beginning of space flight.

Adaptation, Physiological↗

PubMed2002

[A system for biomaterial handling and sample pretreatment in conditions of weightlessness].

To perform laboratory biochemical, immunologic and microbiological analyses and special pretreatment and stabilization of biosamples immediately on the space station, system Plasma-03 was designed and manufactured and associated procedure for sample collection and pretreatment was developed. Main elements of the system are a refrigerator/thermostat, centrifuge and returnable container, and a set of accessories and expendables. The system meets the requirements to the equipment to be employed in crew health monitoring and biochemical experiments on board the International space station.

Biochemical Phenomena↗

PubMed2002

Responses of sympathoadrenal and renin angiotensin systems to stress stimuli in humans during real and simulated microgravity.

Changes of plasma hormone levels were investigated in human subjects after exposure to physical exercise (WL) and insulin induced hypoglycemia (ITT) during space flight or after head down bed rest (HDBR). Exaggerated responses of plasma epinephrine (EPI), norepinephrine (NE) and aldosterone (ALD) were observed after WL during space flight as compared to preflight response. Hypoglycemia during space flight induced attenuated responses of EPI, NE and augmented response of ALD. Exposure to WL during HDBR was followed by significantly exaggerated responses of plasma EPI, NE, ALD, PRA and cortisol. In HDBR the responses of plasma EPI, NE and cortisol were reduced and PRA response was exaggerated during ITT. These data indicate that hormonal responses to ITT and WL are similar at real and simulated microgravity.

Comparative Study↗

PubMed2001

[Evaluation of effectiveness of water-salt supplement in the long-duration "MIR" missions].

Long-term stay of human in microgravity instigates body hypohydration. Specifically, it leads to noticeable reduction in the extracellular fluid volume and consequent orthostatic instability and some other hemodynamic disorders immediately after flight. To prevent these developments and to improve g-tolerance during descent, the cosmonauts administered a complex of end-of-flight countermeasures consisting of, besides the physical and LBNP training sessions, water-salt supplements (WSS). Basing on the experience of WSS application in long-duration space flights we can assert the effectiveness of this method of pharmacological body hydration maintenance on the phase of preparation for descent and the post-landing period. The present work is an attempt to analyze the data about WSS administration and effectiveness on the program of the MIR long-term missions.

Dietary Supplements↗

PubMed2001

Effect of microgravity on plasma catecholamine responses to stressors during space flight.

The effect of microgravity on the sympathicoadrenal system (SAS) activity in humans and animals has not yet been clarified. Our previous studies suggested that the SAS activity, evaluated by circulating and/or urinary catecholamine (CA) levels in astronauts during space flights, was found to be rather unchanged. However, CA levels were measured in astronauts only at rest conditions. The aim of the present study was to investigate effect of microgravity during space flight and post-flight readaptation on responsiveness of the SAS to somatic and psychic stressors evaluated by levels of catecholamines and their metabolite in the blood of the Slovak cosmonaut during his stay on board the space station Mir.

Adaptation, Physiological↗

PubMed2001

Plasma hormone levels in human subject during stress loads in microgravity and at readaptation to Earth's gravity.

In great part of the investigations of endocrine system functions in astronauts during space flights the plasma levels of hormones and metabolites were determined only in resting conditions, usually from one blood sample collection. Such levels reflected the psychical and physical state and new hormonal homeostasis of organism at the time of blood collection, however, the functional capacity of neuroendocrine system to respond to various stress stimuli during space flight remained unknown. The aim of present investigations was to study dynamic changes of hormone levels during the stress and metabolic loads (insulin induced hypoglycemia, physical exercise and oral glucose tolerance test) at the exposure of human subject to microgravity on the space station MIR. The responses of sympatico-adrenomedullary system to these stress and workloads were presented by Kvetnansky et al.

Adaptation, Physiological↗

PubMed2000

[Mechanisms of volume regulation under the effect of spaceflight factors].

Studied was the significance of the volume regulating system of the human body for adaptive readjustment of the water-electrolyte homeostasis to changed position, immersion, and microgravity. Experiments were made to investigate volume regulation and associated events and their sequence as during simulation studies (bed rest, immersion, tilting, g-loads), so in Salyut-7 and Mir missions from 7 to 438 days of length. Established was a distinct relationship between the central venous pressure and hydration state of the body, and determined were quantitative parameters of circulating blood migration along the body axis during HDT and hypovolemia. The experiments revealed interdependence of g-tolerance and the way hypohydration had been triggered by, the mechanism of which was also explored. Investigations of human early adaptation to space flight allowed development of an approach to the hydration control (pharmacological hypohydration) with the purpose to minimize discomfort and to improve human performance at the beginning of space mission.

Adaptation, Physiological↗

PubMed1999

Endocrine status and LBNP-induced hormone changes during a 438-day spaceflight: a case study.

We investigated basal levels and lower body negative pressure (LBNP)-induced changes of volume regulating (PRA, aldosterone, AVP, ANP99-126) and other stress-sensitive hormones (catecholamines, cortisol, ACTH) in venous plasma from one cosmonaut before (-45 d), during (3, 170, 287, 430 d) and after (+4, +90 d) a record-breaking long-term (438 d) spaceflight. Blood was taken at the beginning and immediately after ending LBNP (-15/-30/-35 mm Hg for 15/15/10 min, respectively) preflight supine, inflight, and postflight supine. PRA, aldosterone, and vasopressin levels stayed within normal boundaries during the entire flight and after landing. Catecholamines exceeded reference limits (epinephrine > 140 pg x ml(-1), norepinephrine >1000 pg x ml(-1) 5 and 9 mo inflight, and 4 d postflight. ANP and cGMP were lower inflight (p<0.04) than pre- or postflight. Cortisol and ACTH were not consistently altered. LBNP-induced hormonal changes were not different (p>0.05) in microgravity and 1-G. Based on data from one cosmonaut, we conclude that long-term spaceflight up to 430 d duration appeared to lower plasma ANP and cGMP during flight and occasionally elevate catecholamine levels, without significantly altering LBNP-induced relative hormone changes as compared with those observed on the ground.

Adaptation, Physiological↗

PubMed1998

[Hematological investigations in conditions of long-term space flights].

In the nearly 15-month mission aboard MIR the cosmonaut-physician and members of three crews (MIR-15, -16, and -17) carried out a program of hematological investigations. Most of the changes related to the red blood system and included reduction in hemoglobin and hematocrit. Erythrocytes had decreased concentration and took on abnormal forms. There were also signs of altered metabolism of erythrocytes. Of interest are phase-by-phase variations in the levels of erythrocytes in the course of long-term stay in microgravity, and absence of a convincing correlation between hemoglobin, erythrocyte and hematocrit levels. But for lymphocytosis that returned to the norm already on the first day of recovery, no material changes occurred to the leukocyte profile. Investigations at the landing site displayed erythropenia, decreased reticulocytes and ensuing reticulocyte reaction, and gradual regain of the erythrocyte number that can be viewed as a normal physiological reaction of the blood system to the set of factors of spaceflight and early readaptation. Besides, the investigations showed a large individually of blood reactions to prolonged stay in space flight.

Adaptation, Physiological↗

PubMed1998

[Dynamic changes in the reactivity of the hormonal system regulation with the impact by LBNP sessions in long-term space mission].

Experiment INTERSTITIUM was performed on days 3, 170, 287, and 430 of the long-term MIR mission of the Russian cosmonaut-physician in order to evaluate reactivity of the system of hormonal regulation of homeostasis during LBNP sessions. Data of the experiment displayed different types of reaction of the volume controls to LBNP at the onset (F-3), in the course of and soon after recovery (R-4) from the extended mission which are signs of specific phases of adaptive shifts in the organism of cosmonaut. Exaggerated reactivity of the hormonal systems during LBNP in flight suggests more significant consequences of the test for the cardiovascular system of human in microgravity. The most expressed hormonal reaction to LBNP was documented at the very beginning of the postflight period. Plasma cGMP was materially reduced in the process of the mission and remained quite low on R-4; return of nucleotides to the norm was observed no earlier than on R-90. Complete recovery from the space mission took three months when the hormonal reaction to LBNP was same as prior to launch.

Hormones↗

PubMed1997

[Functional test with potassium chloride following long-term space mission].

To look into the potassiuretic function of kidneys in 11 cosmonauts on the second day post recovery after six-month MIR missions, functional testing with potassium chloride was performed. The following standard procedure was used before and after the missions: during morning hours fasting test-subjects consumed a 10% solution of potassium chloride in the amount of 0.55 ml/kg or 0.75 mmol of potassium per a kilogram of body mass with some additional liquid in the amount of 10 ml/kg of body mass. Later on, urine was collected for four hours. Administration of the potassium loading test after missions did not reveal any significant group-average changes in potassium excretion as compared with pre-flight levels; meanwhile, calcium excretion was increased. Reduced blood concentrations of potassium were determined in each of the cosmonauts immediately after landing. The main contributor to retaining of the renal potassiuretic function after prolonged missions appears to be the effective inflight physical countermeasures against the musculoskeletal deconditioning of the human body.

Adaptation, Physiological↗

PubMed1996

[Effect of short- and long-time space flights on some biochemical and physical-chemical parameters of cosmonauts' blood].

The purpose of the present investigation was to look for original approaches to the analysis of physical-chemical (osmolality, sodium, potassium, and calcium concentrations) and hormonal (cortisol, aldosterone, vasopressin, parathormone, calcitonin) parameters of cosmonauts' serum. To this event, we investigated 35 cosmonauts who had made either short- (up to 8 days) or long-term (up to 366 days) space flights. The dispersion factor of these parameters was found to be a criterion for assessment of the reaction of human regulatory systems to extreme impacts. No evident correlative link between the preflight and postflight concentrations of inorganic serum components was established; however, there was a high correlation of parathormone and cortisol concentrations inferring the participation of these hormones in readaptation. Integral analysis of all the mineral and hormonal parameters of blood serum shapes them into something unique apt to change after flight. Our data alludes to the fact that the approaches used for evaluation of the data resulting from conventional techniques open up new possibilities for prediction of changes in and identification of the character of individual reaction of humans to the spaceflight factors.

Astronauts↗