Wyniki wyszukiwania - AGRO

1

Intermittent hypoxia: mechanisms of action and some applications to bronchial asthma treatment

100%

Serebrovskaya T. V., Swanson R. J., Kolesnikova E. E.

Journal of Physiology and Pharmacology. Supplement

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2003

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tom 54

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nr 1

35-41

Being essentially cut off from the global scientific community, Ukrainian and Russian scientists have developed a new concept for the beneficial use of adaptation to artificial intermittent hypoxia in treating of many diseases. The basic mechanisms underlying intermittent hypoxic training were elaborated mainly in three areas: regulation of respiration, free radical production and mitochondrial respiration. Twenty-year experience of the application of intermittent hypoxic therapy for the treatment of chronic obstructive bronchitis and bronchial asthma allows affirming that the adaptation to this kind of hypoxia causes a significant improvement of the clinical picture or even a complete recovery. The absence of negative side effects, typically observed during drug therapy, and the stimulation of organism’s general, nonspecific resistance, makes the hypoxic therapy a treatment with a future. A special note is devoted to the use of intermittent hypoxic training in industrial health care for the purpose of prophylaxis and treatment of professional diseases.

2

Effects of training on the ventilatory response to hypoxia

100%

Adamczyk W., Tafil-Klawe M., Chesy G., Klawe J. J., Szeliga-Wczysla M., Zlomanczuk P.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 4

7-14

The purpose of the present study was to examine the influence of systematical training on the ventilatory response to hypoxia. A rebreathing technique - progressive isocapnic hypoxia - was used to measure hypoxic chemoreflex reactivity. The ventilatory response was measured in a group of 22 world class adult kayakers (22.6 ±1.9 yr), 16 young kayakers (17.8 ±1.1 yr), and 38 control subjects (21.9 ±1.9 yr). The ventilatory response to hypoxia - analyzed as the relationship (slope) MV/SaO2 (minute ventilation/oxygen arterial blood saturation) - in the adult kayakers was significantly lower (-1.03 ±0.28 L/min/%, P<0.01) compared with those in the control group (-1.81 ±0.54 L/min/%) and the young kayakers (-1.54 ±0.6 L/min/%; the difference between the latter two was insignificant). The following values of P0.1/SaO2 (mouth occlusion pressure/oxygen arterial blood saturation) relationship were found for the investigated groups: adult kayakers (-0.20 ±0.1 cmH2O/%, P<0.05), young kayakers (-0.47 ±0.1 cmH2O/%, N.S.), control group (-0.48 ±0.18 cm H2O/%). Correlation between the hypoxic ventilatory response and VO2max was significant in both groups of kayakers. These findings indicate that tolerance for hypoxia was elevated in the group of athletes compared with the control group. Hypoxic tolerance correlates with the duration of training.

3

Hypoxia and photosynthetic activity in relation to identification of chosen elements of the antioxidative system in leaves of Mnium undulatum

100%

Rzepka A., Krupa J., Slesak I.

Polish Journal of Natural Sciences. Supplement

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2003

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tom 01

4

The effect of vasopressin analogue [d[CH2]1-5, Tyr[Me]2] AVP on memory process in rats with experimental amnesia

100%

Car H., Borawska M., Wisniewski K.

Acta Neurobiologiae Experimentalis

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1995

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tom 55

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nr 3

5

Hypoxia-induced subcellular migration of calcium in the carotid body: an ultrastructural assessment by ion-capture cytochemistry

100%

Pokorski M., Walski M.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr Suppl.

6

Reflex respiratory responses to progressive hyperoxic hypercapnia and normocapnic hypoxia in normocapnic and hypercapnic obstructive sleep apnea patients

86%

Tafil-Klawe M., Klawe J. J., Sikorski W., Drzewiecka B.

Journal of Physiology and Pharmacology. Supplement

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2004

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tom 55

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nr 3

135-138

Ventilatory responses to progressive hypercapnia were analyzed in the normocapnic and hypercapnic obstructive sleep apnea patients (OSA). The rebreathing hypercapnic and hypoxic tests were performed using the computerized equipment (Lungtest, MES), according to Read's method. The ventilatory response to hypoxia was impaired in all OSA patients. Concerning the hypercapnic ventilatory response, there were no differences between the OSA patients with normal end-tidal PCO2 and controls. Nine moderately hypercapnic OSA patients showed a right shift with a normal slope of the regression curve describing the relationship between the end-tidal PCO2 and minute ventilation. In contrast, three severely hypercapnic OSA patients showed a right shift with a decreased slope of this regression curve. We conclude that awake OSA patients who developed hypercapnic ventilatory insufficiency showed an impaired hypercapnic defense reaction.

7

Hypoxic ventilatory profile in the anesthetized rat

86%

Marczak M., Kolesnikova E. E., Pokorski M.

Journal of Physiology and Pharmacology. Supplement

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2004

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tom 55

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nr 3

89-94

In the present study we investigated whether hypocapnia that accompanies hypoxic hyperventilation might affect the biphasic, stimulatory/depressant, ventilatory response to hypoxia. The experiments were carried out in anesthetized, vagotomized, spontaneously breathing, and poikilocapnic rats. The animals were subjected to acute steady-state hypoxia consisting of 12% O2 in N2 in inspiratory mixture. Ventilation and its frequency and volume components were assessed from the integrated electromyographic activity of the diaphragm. We found that despite the development of significant hypocapnia, the hypoxic ventilatory response consisted of rapid stimulation followed by a gradual decline. The frequency component contributed more to the ventilatory increase than that of volume. The results indicate that the hypoxic ventilatory profile in the anesthetized poikilocapnic rat resembles that known to be present during isocapnia. We conclude that hypocapnia neither hampers the hypoxic ventilatory reactivity nor alters the biphasic hypoxic ventilatory profile. These observations may aid planning experimental rat model studies.

8

Antidepressant-like and anxiolytic-like effects of mild hypobaric hypoxia in mice: possible involvement of neuropeptide Y

86%

Duszczyk M., Gamdzyk M., Ziembowicz A., Boguszewski P. M., Lazarewicz J. W., Salinska E.

Acta Neurobiologiae Experimentalis

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2015

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tom 75

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nr 4

Previous studies have demonstrated that repeated submission of rats to mild hypobaric hypoxia reduces the persistent behavioral and hormonal depressive symptoms induced by exposure to footshock in the learned helplessness paradigm. The aim of this study was to determine whether hypoxic preconditioning of mice can also induce antidepressant- and anxiolyticlike effects that are detectable with the other commonly used behavioral tests, and to determine whether these effects are accompanied by an increase in neuropeptide Y (NPY) in the hippocampus, which may suggest the involvement of NPY in these mechanisms. The intermittent mild hypobaric hypoxia was generated by 2-h exposure of mice to 0.47 atm for 3 consecutive days. In the tail suspension test a significant decrease in the duration of immobility was observed 24 h, but not 48 h after the last hypobaric session. The elevated plus maze trials performed 48 h after preconditioning showed a significant increase in the frequency of open arm entries, a reduction in the duration of closed arm occupancy and substantially more time spent in the open arms in comparison to the control groups. The open field test demonstrated the absence of increases in general activity or unspecific exploratory behavior in hypoxia-preconditioned mice. The EIA test detected a statistically significant but relatively weak increase in the NPY content in the hippocampus 24 h after preconditioning. Together, our data demonstrate that preconditioning of mice with intermittent mild hypobaric hypoxia induces anxiolytic- and antidepressantlike effects. They are accompanied by up-regulation of NPY which may suggest its mechanistic role.

9

Statistical evaluation of ventilatory patterns in response to intermittent hypoxia in the rabbit

86%

Sokolowska B., Jozwik A.

Journal of Physiology and Pharmacology. Supplement

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2005

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tom 56

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nr 4

203-207

In the present study we investigated whether classical or non-classical statistical methods might be useful in the diagnosis of early changes evoked by intermittent hypoxia (IH) in an experimental model. The experiments were carried out in anesthetized, spontaneously breathing rabbits. IH consisted of 5 cycles of breathing 14% O2 in N2 for 1 min interspersed with 3 min normoxic intervals. The following ventilatory variables were evaluated: frequency breathing, tidal volume, and minute ventilation. The results indicate that IH had a progressively stimulatory effect on the baseline ventilation and on the hypoxic ventilatory responses. Further, the algorithms of the pattern recognition theory might be a suitable tool for the recognition of early ventilatory effects of recurrent hypoxic events in the IH model. The recognition of IH states may be useful in clinical and sports medicine.

10

Respiratory responses to acute intermittent hypoxia and hypercapnia in awake rats

86%

Sokolowska B., Rekawek A., Jozwik A.

Journal of Physiology and Pharmacology. Supplement

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2008

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tom 59

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nr 6

659-667

11

Perception disorders and behavior changes in high-altitude mountaineers

86%

Banasiewicz T., Przybyl M., Holdys J.

Trends in Sport Sciences

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2014

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tom 21

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nr 1

High-altitude mountaineering involves exposure to reduced partial oxygen pressure, which leads to a number of psychical and physical disturbances in the climber’s body and has an impact on the function of the central nervous system. These disorders can be intensified by external environmental factors such as energy deficit, fatigue, high true altitude, stress and cold. The climber’s central nervous system can experience functional and morphological changes, mostly of a non-permanent character. All these factors can lead to perception disorders and changes of behavior in climbers as compared with their perception abilities and behaviors at lower altitudes. Problems with concentration, rational assessment of situations and one’s own capabilities – and in extreme cases – delusions or autistic symptoms may also occur. Emphatic behaviors of climbers at high altitudes seem to be seriously hindered, since their brain function focuses on survival. An assessment of ethical behaviors in such conditions is very difficult as humans normally behave ethically at “sea-level” where the brain functions properly in under appropriate partial oxygen pressure.

12

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Effect of L-arginine on lead induced oxidative stress in the blood of rats with different resistance to hypoxia

86%

Tkachenko H., Kurhalyuk N., Khabrovska L., Kminski P.

Polish Journal of Food and Nutrition Sciences

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2007

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tom 57

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nr 3

387-393

The aim of the study was to estimate beneficial effects of L-arginine, a nitric oxide precursor, on antioxidant enzymes activity (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, ceruloplasmine), the lipid peroxidation processes level and parameters of membrane erythrocytes resistance before and after lead intoxication in rats with different resistance to hypoxia. Our results suggest that the antioxidant system enzymes activity and lipid peroxidation processes level in animals which differ in sensitiveness to hypoxia, are higher in animals with low resistance to hypoxia in the control group. We have shown that the amino acid, L-arginine, is an efficient antioxidant capable of reducing the level of lipid peroxidation processes in blood of lead-preexposed rats. L-arginine treatment under lead intoxication caused alteration in antioxidant enzymes activity due to increasing the enzymes activity of glutathione system, especially in animals with low resistance to hypoxia. The influence of L-arginine under lead intoxication was investigated to ascertain whether this amino acid possesses antioxidant properties before lead injection (preventive effect) and whether L-arginine has therapeutic effects by treatment after lead intoxication. We have shown a significant protective effect of L-arginine under treatment with a preventive effect before lead intoxication. These studies suggest that L-arginine may be a useful drug in treatment under lead intoxication.

13

Ventilatory augmentation by acute intermittent hypoxia in the rabbit

86%

Sokolowska B., Pokorski M.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 4

341-347

This study seeks to determine the effects on respiratory function of acute intermittent hypoxia. The experiments were performed on anesthetized, spontaneously breathing rabbits. The experimental protocol consisted of 5 one-minute episodes of hypoxia (14% O2 in N2) interspersed with three-minute normoxic recovery periods. Ventilatory variables, minute ventilation (MV) and its tidal and frequency components, were derived from the continuously recorded airflow signal. We found that MV progressively increased with each next hypoxic-normoxic cycle; the increases were driven by both ventilatory components. Ventilatory augmentation concerned both the stimulus (hypoxic) and recovery (normoxic) periods, but it was significantly greater in the former. The augmented ventilation was sustained for up to 30 min after the last hypoxic run, which suggests the appearance of ventilatory long-term facilitation. The results demonstrate that acute intermittent hypoxia consisting of a few hypoxic-normoxic cycles is capable of inducing appreciable ventilatory changes. Such changes reflect plasticity of the respiratory motor output developing on a short-term basis during ongoing cycles of hypoxia, which, in the present study, correlated with the number of hypoxic cycle. Ventilatory augmentation in response to acute cyclic hypoxic episodes may give insights into the mechanisms of respiratory improvement by intermittent hypoxic training, increasingly used in both sports physiology and medicinal approaches.

14

Chronic mountain sickness: the reaction of physical disorders to chronic hypoxia

86%

Zubieta-Castillo G.,Sr, Zubieta-Calleja G.R.,Jr, Zubieta-Calleja L.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 4

431-442

Chronic mountain sickness (CMS) is a condition in which hematocrit is increased above the normal level in residents at high altitude. In this article we take issue with the ‘Consensus Statement On Chronic And Subacute High Altitude Diseases” of 2005 on two essential points: using a questionnaire to evaluate the symptoms of CMS to use the term “loss of adaptation” as opposed to “adaptation to disease in the hypoxic environment”. We opine that CMS is rather an adaptive reaction to an underlying malfunction of some organs and no specific symptoms could be quantified. To substantiate our line of reasoning we reviewed 240 CMS cases seen at the High Altitude Pathology Institute in La Paz. Patients who had a high hematocrit (>58%) underwent pulmonary function studies in search for the cause of hypoxia: hypoventilation, diffusion alteration, shunts, and uneven ventilation-perfusion. The tests included arterial blood gas tests, chest x-rays, spirometry, hyperoxic tests, flow-volume curves, ventilation studies at rest and during exercise, ECG, exercise testing and doppler color echocardiography to assess heart structure and function. When correlated with clinical history these results revealed that CMS is practically always secondary to some type of anomaly in cardio-respiratory or renal function. Therefore, a questionnaire that tries to catalog symptoms common to many types of diseases that lead to hypoxia is flawed because it leads to incomplete diagnosis and inappropriate treatment. CMS, once again, was shown to be an adaptation of the blood transport system to a deficient organs’ function due to diverse disease processes; the adaptation aimed at sustaining normoxia at the cellular level in the hypoxic environment at high altitude.

15

In vitro reoxygenation following hypoxia increases MMP-2 and TIMP-2 secretion by human umbilical vein endothelial cells

86%

Cavdar Z., Oktay G., Egrilmez M. Y., Genc S., Genc K., Altun Z., Islekel H., Guner G.

Acta Biochimica Polonica

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2010

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tom 57

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nr 1

69-73

Endothelial cells lining the inner blood vessel walls play a key role in the response to hypoxia, which is frequently encountered in clinical conditions such as myocardial infarction, renal ischemia and cerebral ischemia. In the present study we investigated the effects of hypoxia and hypoxia/reoxygenation on gelatinases (matrix metalloproteinase-2 and -9), their inhibitor (TIMP-2) and activator (MT1-MMP), in human umbilical vein endothelial (HUVE) cells. HUVE cells were subjected to 4 h of hypoxia or hypoxia followed by 4 and 24 h of reoxygenation. The pro- and active forms of MMP-2 and MMP-9 were analyzed by gelatin zymography; TIMP-2 protein level was assayed using ELISA, while MT1-MMP activity was measured using an activity assay. The secretion of MMP-2 proform increased significantly in cells subjected to 4h of hypoxia followed by 4 or 24 h of reoxygenation, compared with the normoxic group. TIMP-2 protein level also increased significantly in the hypoxia/reoxygenation groups, compared with the normoxic group. There were no statistically significant differences in the levels of active MT1-MMP in all groups. This study indicates that MMP-2 and TIMP-2 could be regarded as important components of a mechanism in the pathophysiology of ischemic injury following reperfusion.

16

Antiproliferative activity of new benzimidazole derivatives

86%

Blaszczak-Swiatkiewicz K., Olszewska P., Mikiciuk-Olasik E.

Acta Biochimica Polonica

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2013

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tom 60

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nr 3

A series of new benzimidazole derivatives were synthesized and tested in vitro for possible anticancer activity. Their effect of proliferation into selected tumor cell lines at normoxia and hypoxia conditions was determined by WST-1 test. Additionally, apoptosis test (caspase 3/7 assay) was used to check the mode caused by the agents of cell death. Four of the examined compounds (7, 8, 13, 11) showed a very good antiproliferative effect and three of them were specific for hypoxia conditions (8, 14, 11). Compound 8 was the most cytotoxic against human lung adenocarcinoma A549 cells at hypoxic conditions. Hypoxia/ normoxia cytotoxic coefficient of compound 14 (4.75) is close to hypoxia/normoxia cytotoxic coefficient of tirapazamine (5.59) - a reference compound in our experiments and this parameter locates it between mitomycin C and 2-nitroimidazole (misonidazole). Screening test of caspase-dependent apoptosis proved that exposure to A549 cells of compounds 7-8 and 13-14 for 48 h promote apoptotic cell death. These results supplement our earlier study of the activity of new potentialy cytotoxic heterocyclic compounds against selected tumor cells.

17

Cortical activity during hypoxic hyperventilation

86%

Pokorski M., Trojecka A., Marczak M., Wierzbicka A., Jernajczyk W.

Journal of Physiology and Pharmacology. Supplement

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2003

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tom 54

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nr 1

29-34

This study seeks to determine the pattern of electroencephalogram changes during stimulatory ventilatory responses to acute progressive hypoxia. Electroencephalograms were recorded in the 10-20 electrode system during progressive poikilocapnic hypoxic tests based on the rebreathing routine. Healthy subjects were used for he study. A major finding was that hypoxia decreased the power spectra of the alpha activity. The decrease was surprisingly rapid and greater at mild hypoxic desaturation when pulmonary ventilation was about to pick up than during the maximum hypoxic hyperventilation. The possible relation of hypoxic decline in brain bioactivity to the manifestation of hypoxic hyperventilation remains to be elucidated in further studies.

18

Non-invasive measurement of circulation time using pulse oximetry during breath holding in chronic hypoxia

86%

Zubieta-Calleja G. R., Zubieta-Castillo G., Paulev P.-E., Zubieta-Calleja L.

Journal of Physiology and Pharmacology. Supplement

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2005

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tom 56

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nr 4

251-256

Pulse oximetry during breath-holding (BH) in normal residents at high altitude (3510 m) shows a typical graph pattern. Following a deep inspiration to total lung capacity (TLC) and subsequent breath-holding, a fall in oxyhemoglobin saturation (SaO2) is observed after 16 s. The down-pointed peak in SaO2 corresponds to the blood circulation time from the alveoli to the finger where the pulse oximeter probe is placed. This simple maneuver corroborates the measurement of circulation time by other methods. This phenomenon is even observed when the subject breathes 88% oxygen (PIO2 = 403 mmHg for a barometric pressure of 495 mmHg). BH time is, as expected, prolonged under these circumstances. Thus the time delay of blood circulation from pulmonary alveoli to a finger is measured non-invasively. In the present study we used this method to compare the circulation time in 20 healthy male high altitude residents (Group N with a mean hematocrit of 50%) and 17 chronic mountain sickness patients (Group CMS with a mean hematocrit of 69%). In the two study groups, the mean circulation time amounted to 15.94 ±2.57 s (SD) and to 15.66 ±2.74 s, respectively. The minimal difference was not significant. We conclude that the CMS patients adapted their oxygen transport rate to the rise in hematocrit and blood viscosity.

19

Effect of hypoxia on toxicity induced by anticancer agents in cardiomyocyte culture

86%

Mandziuk S., Kus P., Dudka J., Madej-Czerwonka B., Cendrowska-Pinkosz M., Iwan M., Luszczewska-Sierakowska I., Korga A.

Medycyna Weterynaryjna

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2014

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tom 70

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nr 05

The main goal of the study was to determine whether hypoxia augments the toxicity of anticancer drugs towards cardiomyocytes. Drugs selected for this experiment were those that disturb the cardiac redox equilibrium. Cardiomyocytes were incubated for 24 h with doxorubicin, tirapazamine, and 5-fluorouracil, each at three doses, under normoxia and under 50% and 90% hypoxia. The cytotoxic effect was evaluated on the basis of the percentage of living cells, cell vitality (assessed by the MTT assay), and morphology. In addition, the oxidative marker and pH value were determined. Varied protective effects of hypoxia on cell morphology were observed in all cases except the medium concentration of tirapazamine. The 50% hypoxia prevented the toxic effects of all tested drugs. The 90% hypoxia, on the other hand, was effective against the cytotoxic action of doxorubicin and 5-fluoruracil, but the cytotoxicity of tirapazamine increased. It was found that under the 90% hypoxia the oxidative stress observed under normoxia and the 50% hypoxia was greatly reduced. The study revealed that the above drugs did not activate anaerobic glycolysis.

20

Hypoventilation in chronic mountain sickness: a mechanism to preserve energy

86%

Zubieta-Calleja G. R., Paulev P.-E., Zubieta-Calleja L., Zubieta-Calleja N., Zubieta-Castillo G.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 4

425-430

Chronic Mountain Sickness (CMS) patients have repeatedly been found to hypoventilate. Low saturation in CMS is attributed to hypoventilation. Although this observation seems logical, a further understanding of the exact mechanism of hypoxia is mandatory. An exercise study using the Bruce Protocol in CMS (n = 13) compared to normals N (n = 17), measuring ventilation (VE), pulse (P), and saturation by pulse oximetry (SaO2) was performed. Ventilation at rest while standing, prior to exercise in a treadmill was indeed lower in CMS (8.37 l/min compared with 9.54 l/min in N). However, during exercise, stage one through four, ventilation and cardiac frequency both remained higher than in N. In spite of this, SaO2 gradually decreased. Although CMS subjects increased ventilation and heart rate more than N, saturation was not sustained, suggesting respiratory insufficiency. The degree of veno-arterial shunting of blood is obviously higher in the CMS patients both at rest and during exercise as judged from the SaO2 values. The higher shunt fraction is due probably to a larger degree of trapped air in the lungs with uneven ventilation of the CMS patients. One can infer that hypoventilation at rest is an energy saving mechanism of the pneumo-dynamic and hemo-dynamic pumps. Increased ventilation would achieve an unnecessary high SaO2 at rest (low metabolism). This is particularly true during sleep.

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