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Biomedical subjects

V I Kolesnikov

Publications and source records attributed to V I Kolesnikov.

16 recordsLinked to original sources
PubMed2006

[Cardiorespiratory responses of animals to passive orthostasis after intermittent hypoxia during head-down tilt].

Cardiorespiratory responses induced by upright tilt before and after intermittent hypoxia during head-down tilt, were investigated in rabbits. Arterial blood pressure, heart rate, central venous pressure, transmural filling pressure of the heart (calculated as the product of esophageal and central venous pressure), breathing frequency, esophageal pressure were measured in supine (baseline), head-down and upright posture. Our results indicate a reduction in orthostatic responses in cardiovascular system after intermittent hypoxia.

Animals↗
PubMed2005

Omega- and Omega+ production in central Pb + Pb collisions at 40 and 158A GeV.

Results are presented on Omega production in central Pb+Pb collisions at 40 and 158A GeV beam energy. For the first time in heavy ion reactions, rapidity distributions and total yields were measured for the sum Omega(-) + Omega(+) at 40A GeV and for Omega(-) and Omega(+) separately at 158A GeV. The yields are strongly underpredicted by the string-hadronic UrQMD model but agree better with predictions from hadron gas models.

Journal Article↗
PubMed2005

System-size dependence of strangeness production in nucleus-nucleus collisions at squareroot[sNN]=17.3 GeV.

Emission of pi+/-, K+/-, phi, and Lambda was measured in near-central C+C and Si+Si collisions at 158 AGeV beam energy. Together with earlier data for p+p, S+S, and Pb+Pb, the system-size dependence of relative strangeness production in nucleus-nucleus collisions is obtained. Its fast rise and the saturation observed at about 60 participating nucleons can be understood as the onset of the formation of coherent systems of increasing size.

Journal Article↗
PubMed2005

[The dynamic of breathing biomechanics and intrathoracic hemodynamics parameters during microgravity modeling].

In ground-based model of the hemodynamics effects of weightlessness, the intersystem relation of breathing and circulation was investigated during inspiration and expiration separately in anesthetized catz. It's shown that the dynamics of central venous pressure, esophageal pressure and filling pressure of the heart during inspiration in supine and head-down tilt position has obvious similarity to those which hypothetically can be present in microgravity. The results suggest that intrathoracic hemodynamics during inspiration in supine and head-down position may be an adequate ground model for investigation of weightlessness influences on intrathoracic circulation.

Animals↗
PubMed2005

[The effect of head-down hypokinesia on functional state of diaphragm in rats].

The effects of long-term (21 days) head-down (-30 degrees) hypokinesia (HDH) on respiratory system and a functional state of diaphragm were investigated in rats. Minute ventilation, oesophageal and abdominal pressure, integrated electrical activity of diaphragm were measured in control and experimental group (after 21 days of HDH) of animals. The measurements were made in several body positions atresting and in occlusion breathing. The results indicate that HDH causes reduction in minute ventilation of lungs, decrease in orthostatic stability and functional reserve of the respiratory system capacity. It was established that the basic mechanism of HDH respiratory effects is contractile failure of diaphragm related to damage in excitation-contraction coupling in its muscular fibres.

Animals↗
PubMed2004

Lambda and lambda production in central Pb-Pb collisions at 40, 80, and 158A GeV.

Production of Lambda and Antilambda hyperons was measured in central Pb-Pb collisions at 40, 80, and 158A GeV beam energy on a fixed target. Transverse mass spectra and rapidity distributions are given for all three energies. The Lambda/pi ratio at midrapidity and in full phase space shows a pronounced maximum between the highest BNL Alternating Gradient Synchrotron and 40A GeV CERN Super Proton Synchrotron energies, whereas the Lambda/pi ratio exhibits a monotonic increase.

Journal Article↗
PubMed2004

Evidence for an exotic S= -2, Q= -2 baryon resonance in proton-proton collisions at the CERN SPS.

Results of resonance searches in the Xi(-)pi(-), Xi(-)pi(+), Xi;(+)pi(-), and Xi;(+)pi(+) invariant mass spectra in proton-proton collisions at sqrt[s]=17.2 GeV are presented. Evidence is shown for the existence of a narrow Xi(-)pi(-) baryon resonance with mass of 1.862+/-0.002 GeV/c(2) and width below the detector resolution of about 0.018 GeV/c(2). The significance is estimated to be above 4.2sigma. This state is a candidate for the hypothetical exotic Xi(--)(3/2) baryon with S=-2, I=3 / 2, and a quark content of (dsdsū). At the same mass, a peak is observed in the Xi(-)pi(+) spectrum which is a candidate for the Xi(0)(3/2) member of this isospin quartet with a quark content of (dsus[-]d). The corresponding antibaryon spectra also show enhancements at the same invariant mass.

Journal Article↗
PubMed2003

Influence of changes in intrathoracic and central venous pressure on cardiac filling dynamics.

Changes in the ratio between intrathoracic and central venous pressure were studied in narcotized cats under conditions of constant positive or negative pressure ventilation. Transformation of elastic characteristics in the respiratory system caused by changes in intrathoracic pressure led to inversion of the ratio between transpulmonary intrathoracic and central venous pressure determining right atrial filling pressure.

Animals↗
PubMed2003

[Comparative evaluation of several methods preventing orthostatic disorders during simulation of the end-of-space-mission factors].

A new method for mitigation of the negative consequences of blood shift toward the cranial end as a result of simulation of the hemodynamic effects of microgravity (head-down tilt at -6 degrees) combines the lower body negative pressure (LBNP) and negative pressure respiration (NPR) to accelerate blood outflow from cerebral vessels and, additively, to restrain blood inflow from the lower body. The longitudinal hydrostatic pressure gradient is thus reproduced but main hemodynamic parameters assume values characteristic of the vertical posture. The objective was to compare the strength of LBNP and LBNP + NRP training in preventing orthostatic disorders following 7-d HDT. Subjects were 6 male volunteers aged 24 to 40 yrs. In the control experiment, every subject experienced episodes of orthostatic disorders. In the second experiment (LBNP), 4 subjects were afflicted; in the third experiment (LBNP + NPR), orthostatic disorders were minor, if at all. Absence of profound hemodynamic, autonomic or pre-syncope symptoms leads to the conclusion that combination LBNP + NPR is a more favorable preventive method than discrete LBNP.

Adult↗
PubMed2001

Event-by-event fluctuations of the Kaon-to-Pion ratio in central Pb+Pb collisions at 158 GeV per nucleon.

We present the first measurement of fluctuations from event to event in the production of strange particles in collisions of heavy nuclei. The ratio of charged kaons to charged pions is determined for individual central Pb+Pb collisions. After accounting for the fluctuations due to detector resolution and finite number statistics we derive an upper limit on genuine nonstatistical fluctuations, which could be related to a first- or second-order QCD phase transition. Such fluctuations are shown to be very small.

Journal Article↗
PubMed2000

[Some mechanisms of modeling the hydrostatic component of hemodynamics in microgravity].

Proposed is a modified method to counteract the headword redistribution of local blood volumes in microgravity by discrete or combined exposure to respiration at negative pressure (RNP) and lower body negative pressure (LBNP). Physically and physiologically substantiated levels of the barometric influences on the central and peripheral hemodynamics to approximate the normal gradients of blood hydrostatic pressure along the body axis are given. Discrete RNP applied to test-subjects during HDT was shown to return the cerebral and cervical hemodynamic parameters to levels determined in horizontal position. Combination of RNP and LBNP had additive character as it advantaged the recovery of values characteristic of the orthostatic position. There are technical possibilities to integrate the LBNP and RNP devices for the benefit of scientific, certification, predictive, and training objectives of space biomedicine.

Adaptation, Physiological↗
PubMed1998

[Functional status of respiratory muscles and physical endurance among women under prolonged hypokinesia].

Validity of the hypothesis for the role of the respiratory muscles in deterioration of physical work capacity following long-term hypokinesia was tested. Experiments were performed with participation of 8 female subjects aged from 27 to 36 years in the 120-day head-down bed rest. Physical performance and functional status of the respiratory muscles have been determined during incremental loading on bicycle ergometer with normal respiration and breathing against additional external resistance. Functional deficit of the respiratory muscles due to long-term bed rest was shown not to allow adequate ventilation and gas exchange at submaximal loads. This resulted in dyspnea, hypoventilation-induced decrease in oxygen consumption and carbon dioxide release, hypercapnia, and lowered threshold of anaerobic metabolism which, in parallel with the deconditioning of the cardiovascular system and the skeletal anti-g musculature, were responsible for degradation of aerobic physical work capacity.

Adult↗
PubMed1998

[Prevention of respiratory muscles deconditioning and deterioration of aerobic working capacity in prolonged weightlessness and hypokinesia].

According to the previous study [2], simulation of the physiological effects of weightlessness leads to deconditioning of the respiratory muscles which, in its turn, may be a factor impacting the aerobic working capacity. In the present work the experimental findings laid the basis for a physiological concept for medical/engineering requirements to countermeasures against deconditioning of the respiratory muscles, designing and laboratory and physiological testing of a prototype of training loading vest Elastik-R. The vest was shown to enhance speed and force qualities of the respiratory muscles in training athletes, to improve ventilation and gas-exchange functions of the lung, and to increase physical performance and aerobic capacity. Recommendations on utilization of the Elastik-R vest during space flight have been issued.

Adolescent↗
PubMed1987

[Erdheim's disease: morphogenetic problems].

Structural studies of resistive vessels in a 21-year-old woman who died in the postpartum period from rupture of the aorta in the presence of Erdheim's disease are described. Histological, histochemical, and immunomorphological methods were used, and microcirculation was examined in film preparations of adventitia treated with silver nitrate by Kupriianov's method. In the media of the aorta and the proximal parts of its large branches, nonspecific necrobiotic processes were in evidence, believed to be due to lesions in the microcirculatory bed of the vascular wall.

Adult↗
PubMedDate not supplied

[Generalized coxsackie infection in an adult male].

An observation of a generalized Coxsackie infection in a male of 45 diagnosed at necropsy is described. The disease as developed during the epidemy of the Coxsackie infection, type B, in the Far East Region and was characterized by gravity and multiple syndromes. Immune inflammation in the organs of the nervous, cardiovascular, digestive, urinary-genital and endocrine systems was revealed as well as severe necrotic myositis. The latter is strictly pathognomonic for this type of infection.

Bone and Bones↗