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Vij A.G.,Defence Institute of Physiology and Allied science DRDO | Kishore K.,Defence Institute of Physiology and Allied science DRDO | Dey J.,Defence Institute of Physiology and Allied science DRDO
Indian Journal of Medical Research | Year: 2012

Background & objectives: People travelling to high altitude for occupational, recreational or religious purposes are mostly healthy and fit but sometimes they use drugs for common ailments like influenza, acute mountain sickness or chronic disease like diabetes. Limitation of oxygen at high altitude may compromise metabolism of drugs. Hence, we undertook this study to assess the effect of hypobaric hypoxia on some commonly used drugs in rats and rabbits. Methods: Effect of intermittent hypobaric hypoxia on phenotypic expression of anesthetic drugs pentabarbitone, thiopentone and zoxazolamine (sleeping time) was assessed in rats exposed to 282.4 mm Hg equivalent to 25000 feet in a decompression chamber. Plasma clearance of some commonly used drugs was investigated in rabbits exposed to 429 mm Hg equivalent to 15000 feet. Pharmacokinetic parameters were computed by plotting drug concentration versus time curve on semi log scale. Results: A significant delay in regaining rightening reflex was observed in rats exposed to intermittent hypobaric hypoxia in response to zoxazolamine, pentobarbitone and thiopentone sodium. Pharmacokinetics of acetyl salicylic acid, gentamicin, phenobarbitone and acetazolamide showed increase in plasma half life (t 1/2), decrease in elimination rate constant (k el) and hence prolonged residence of these drugs in hypoxic animals. Interpretation & conclusions: This experimental study showed that hypoxia altered therapeutic effectiveness and clearance of several drugs, in rats and rabbits exposed to intermittent hypobaric hypoxia. such studies need to be done in human volunteers to see the effect of hypoxia on pharmacokinetics of some common drugs.

Suryakumar G.,Defence Institute of Physiology and Allied science DRDO | Purushothaman J.,Defence Institute of Physiology and Allied science DRDO | Purushothaman J.,Indian National Institute for Interdisciplinary Science and Technology | Shukla D.,Defence Institute of Physiology and Allied science DRDO | And 5 more authors.
Evidence-based Complementary and Alternative Medicine | Year: 2011

Cerebral and pulmonary syndromes may develop in unacclimatized individuals shortly after ascent to high altitude resulting in high altitude illness, which may occur due to extravasation of fluid from intra to extravascular space in the brain, lungs and peripheral tissues. The objective of the present study was to evaluate the potential of seabuckthorn (SBT) (Hippophae rhamnoides L.) leaf extract (LE) in curtailing hypoxia-induced transvascular permeability in the lungs by measuring lung water content, leakage of fluorescein dye into the lungs and further confirmation by quantitation of albumin and protein in the bronchoalveolar lavage fluid (BALF). Exposure of rats to hypoxia caused a significant increase in the transvascular leakage in the lungs. The SBT LE treated animals showed a significant decrease in hypoxia-induced vascular permeability evidenced by decreased water content and fluorescein leakage in the lungs and decreased albumin and protein content in the BALF. The SBT extract was also able to significantly attenuate hypoxia-induced increase in the levels of proinflammatory cytokines and decrease hypoxia-induced oxidative stress by stabilizing the levels of reduced glutathione and antioxidant enzymes. Pretreatment of the extract also resulted in a significant decrease in the circulatory catecholamines and significant increase in the vasorelaxation of the pulmonary arterial rings as compared with the controls. Further, the extract significantly attenuated hypoxia-induced increase in the VEGF levels in the plasma, BALF (ELISA) and lungs (immunohistochemistry). These observations suggest that SBT LE is able to provide significant protection against hypoxia-induced pulmonary vascular leakage. Copyright © 2011 Jayamurthy Purushothaman et al.

Chatterjee A.,Defence Institute of Physiology and Allied science DRDO | Ray K.,Defence Institute of Physiology and Allied science DRDO | Panjwani U.,Defence Institute of Physiology and Allied science DRDO | Thakur L.,Defence Institute of Physiology and Allied science DRDO | Anand J.P.,Defence Institute of Physiology and Allied science DRDO
Indian Journal of Medical Research | Year: 2012

Background & objectives: Decline in cognitive functions is a major challenge for professionals during sustained wakefulness. We used middle latency response (MLR), event related potentials P300-ERP and contingent negative variation (CNV) and Raven's Advanced Progressive Matrices (RAPM) - a standard neuropsychological test were used to evaluate cognitive impairment after total sleep deprivation (SD); and to study the impact of meditation as an intervention for this impairment. Methods: Healthy male volunteers (n=10) drawn randomly from the Indian Army participated in a 6-night study design executed before and after two months of meditation practice: night 1-adaptation, night 2-baseline, night 3-24 h SD, night 4-recovery sleep, night 5-24 h SD after 60 days meditation, night 6-recovery sleep after SD. A 36 h SD was obtained by keeping the subject awake for 12 h after 24 h SD. Results: The latency and amplitude of P300 increased after 36 h SD. Amplitudes and latencies of both early and late CNV increased after 24 and 36 h SD, indicating defcient orientation and impairment of attention and perception. Prolonged CNV reaction time after 36 h SD manifested defcient motor response following second (imperative) stimulus. Latency of MLR Na registered signifcant change following 36 h SD compared to baseline (P<0.01) and recovery (P<0.05). RAPM score showed signifcant decrease after 36 h of wakefulness indicating impaired analytical ability and diffculty in problem solving. None of these parameters showed any signifcant alteration after SD, following meditation practice. Interpretation & conclusions: The present results showed that SD impaired cognitive performance to graded extents signifcantly, but this deterioration could be improved to a signifcant extent using meditation.

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