Regression of coronary atherosclerosis through healthy lifestyle in coronary artery disease patients--Mount Abu Open Heart Trial.

AIMS: To evaluate the efficacy of a unique healthy and happy lifestyle (HLS) program in regression of coronary atherosclerosis and reduction in cardiac events in an open trial. METHODS: One hundred and twenty three angiographically documented moderate to severe coronary artery disease (CAD) patients were administered HLS comprising of low-fat, high-fiber vegetarian diet, moderate aerobic exercise and stress-management through Rajyoga meditation. Its most salient feature was training in self-responsibility (heal+thy) and self-empowerment through inner-self consciousness (swasth; swa=innerself, sth=consciousness) approach using Rajyoga meditation. Following a seven day in-house sojourn, patients were invited for six month follow-up for reassessment and advanced training. At the end of two years, all patients were asked to undergo repeat angiography. RESULTS: Three hundred and sixty coronary lesions were analysed by two independent angiographers. In CAD patients with most adherence, percent diameter stenosis regressed by 18.23 +/- 12.04 absolute percentage points. 91% patients showed a trend towards regression and 51.4% lesions regressed by more than 10 absolute percentage points. The cardiac events in coronary artery disease patients were: 11 in most adherence, and 38 in least adherence over a follow-up period of 6.48 yrs. (risk ratio; most vs least adherence: 4.32; 95% CI: 1.69-11.705; P < 0.002). CONCLUSION: Overall healthy changes in cardiovascular, metabolic and psychological parameters, decline in absolute percent diameter coronary stenosis and cardiac events in patients of CAD were closely related to HLS adherence. However, more than 50% adherence is essential to achieve a significant change.

Changes in visual evoked potentials on acute induction to high altitude.

BACKGROUND & OBJECTIVES: Induction to high altitude leads to altered central nervous system (CNS) functions induced by hypobaric hypoxia. The sensory systems like visual and auditory systems are reported to be affected by hypoxia. The present study was undertaken to assess the effects of hypobaric hypoxia on visual evoked potentials (VEPs) at 3200 m and 4300 m. METHODS: The VEP of 30 human volunteers were recorded at sea level (SL) and then at high altitude (HA) of 3200 m (HA I) and 4300 m (HA II) in eastern Himalayas and on return to sea level (RSL). The absolute latencies and amplitude of positive and negative waves were recorded. RESULTS: High altitude of 3200 m did not alter the latency of major wave N1, P1 and N2 of the VEPs. At HA II (4300 m), there was a statistically significant increase (P < 0.01) in the latency of NI wave as compared to the SL value and HA I (3200 m) in both left and right eye. There was a slight increase in latenty of P1 wave in both left and right eye at HA II. INTERPRETATION & CONCLUSION: From these results it may be concluded that induction to HA causes increase in latency of N1 wave at 4300 m which is still within physiological limits. This increase in wave latency of N1 wave in both eyes may be due to synaptic delay and/or altered neuronal processing at HA.

Energy cost and cardiorespiratory changes during the practice of Surya Namaskar.

Surya Namaskar (SN), a group of Yogic exercise consists of a set of twelve postures which is practiced by some of the yoga practitioners. The present study was undertaken to observe critically the energy cost and different cardiorespiratory changes during the practice of SN. Twenty-one male volunteers from the Indian Army practiced selected Yogic exercises for six days in a week for three months duration. The Yogic practice schedule consisted of Hatha Yogic Asanas (28 min), Pranayama (10.5 min) and Meditation (5 min). In the Yogic practice schedule 1st they practiced Kapal Bhathi (breathing maneuvers) for 2 min then Yogamudra (yogic postural exercise) for 2 min, after that they took rest until oxygen consumption and heart rate (HR) came to resting value. Subsequently subjects performed SN for 3 min 40 seconds on an average. After three months of training at the beginning of the fourth month subjects performed entire Yogic practice schedule in the laboratory as they practiced during their training session and experiments were carried out. Their pulmonary ventilation, carbondioxide output, Oxygen consumption, HR and other cardiorespiratory parameters were measured during the actual practice of SN. Oxygen consumption was highest in the eighth posture (1.22+/-0.073 1 min(-1)) and lowest in the first posture (0.35+/-0.02 1 min(-1)). Total energy cost throughout the practice of SN was 13.91 kcal and at an average of 3.79 kcal/min. During its practice highest HR was 101+/-13.5 b.p.m. As an aerobic exercise SN seemed to be ideal as it involves both static stretching and slow dynamic component of exercise with optimal stress on the cardiorespiratory system.

Effect of high altitude on human auditory brainstem responses.

The effect of hypobaric hypoxia on Brain Stem Auditory evoked potentials (BAERs) were studied. BAERs were recorded in 30 volunteers at sea level (SL) and then at high altitude (HA) of 3200 m (HA I) and 4300 m (HA II) in Eastern Himalayas and on return to sea level (RSL). The BAERs were recorded using Nicolet Compact - 4 (USA) in response to monaural auditory stimuli consisting of clicks of 100 ps square pulse at a rate of 15/sec. The BAERs were recorded on day 4 of their stay at 3200 m and 4300 m respectively. Findings indicated an increase in absolute peak latencies of wave V at 3200 m, which was statistically significant. On further ascent to 4300 m there was an increase in absolute peak latencies of wave I and III indicating delay in sensory conduction at the medullo-pontine auditory pathways.

Lead induced oxidative stress: beneficial effects of Kombucha tea.

OBJECTIVE: To evaluate the effect of oral administration of Kombucha tea (K-tea) on lead induced oxidative stress. METHODS: Sprague Dawley rats were administered 1 mL of 3.8% lead acetate solution daily alone or in combination with K-tea orally for 45 d, and the antioxidant status and lipid peroxidation were evaluated. RESULTS: Oral administration of lead acetate to rats enhanced lipid peroxidation and release of creatine phosphokinase and decreased levels of reduced glutathione (GSH) and antioxidant enzymes (superoxide dismutase, SOD and glutathione peroxidase, GPx). Lead treatment did not alter humoral immunity, but inhibited DTH response when compared to the control. Lead administration also increased DNA fragmentation in liver. Oral administration of Kombucha tea to rats exposed to lead decreased lipid peroxidation and DNA damage with a concomitant increase in the reduced glutathione level and GPx activity. Kombucha tea supplementation relieved the lead induced immunosuppression to appreciable levels. CONCLUSION: The results suggest that K-tea has potent antioxidant and immunomodulating properties.

High altitude hypoxia: an intricate interplay of oxygen responsive macroevents and micromolecules.

Physiological responses to high altitude hypoxia are complex and involve a range of mechanisms some of which occur within minutes of oxygen deprivation while others reset a cascade of biosynthetic and physiological programs within the cellular milieu. The O2 sensitive events occur at various organisational levels in the body: at the level of organism through an increase in alveolar ventilation involving interaction of chemoreceptors, the respiratory control centers in the medulla and the respiratory muscles and the lung/chest wall systems; at tissue level through the pulmonary vascular smooth muscle constriction and coronary and cerebral vessel vasodilation leading to optimized blood flow to tissues; at cellular level through release of neurotransmitters by the glomus cells of the carotid body, secretion of erythropoietin hormone by kidney and liver cells and release of vascular growth factors by parenchymal cells in many tissues; at molecular level there is expression/activation of an array of genes redirecting the metabolic and other cellular mechanisms to achieve enhanced cell survival under hypoxic environment. Transactivation of various oxygen responsive genes is regulated by the activation of various transcriptional factors which results in expression of genes in a highly coordinated manner. There is thus an intricate cascading interplay of biochemical pathways in response to hypoxia, which causes changes at the physiological and molecular levels. Added to this interplay is the possibility of genetic polymorphism and protein changes to adapt to environmental influences, which may allow a variability in the activity of the pathway. Our understanding of these interactions is growing and one may be close to the precise combination of genetic factors and protein factors that underlie the mechanism of what goes on under high altitude hypoxic stress and who will cope at high altitude.

Immunomodulatory effects of agents of plant origin.

The immunomodulatory properties of amla (Emblica officinalis) and shankhpushpi (Evolvulus alsinoides) were evaluated in adjuvant induced arthritic (AIA) rat model. Injecting Complete Freund's Adjuvant (CFA) in right hind paw of the animals induced inflammation. The crude extracts of both the herbs were administered intraperitonially following a repeated treatment profile. The anti-inflammatory response of both the extracts was determined by lymphocyte proliferation activity and histopathological severity of synovial hyperplasia. Both the extracts showed a marked reduction in inflammation and edema. At cellular level immunosuppression occurred during the early phase of the disease. There was mild synovial hyperplasia and infiltration of few mononuclear cells in amla or shankhpushpi treated animals. The induction of nitric oxide synthase (NOS) was significantly decreased in treated animals as compared to controls. These observations suggest that both the herbal extracts caused immunosuppression in AIA rats, indicating that they may provide an alternative approach to the treatment of arthritis.

Effect of vitamin C and E supplementation in modulating the peripheral nerve conduction following cold exposure in humans.

Exposure to an extremely cold environment without proper protection leading to hypothermia is an emergency, one of the several complications of which is impairment in nerve conduction. Our previous work in the rat model has shown the beneficial effect of vitamin C in modulating the effect of hypothermia on nerve conduction. The present study aimed to evaluate the effect of vitamins C and E, administered alone or in combination, in modulating the effect of mild hypothermia on human ulnar nerve conduction. The study was carried out on 26 volunteers divided into three groups: group I received vitamin C supplementation (2000 mg/day in a single dose and 1,000 mg/day for the next 6 days), group II received vitamins C and E in combination (1,000 mg and 800 mg respectively in a single dose and 500 mg and 400 mg respectively for the next 6 days) and group III received vitamin E (800 mg in a single dose and the same for the next 6 days). The recordings were carried out before and after single and weekly supplementation in each group. There was a fall in ulnar nerve conduction velocity with a reduction in the oral temperature of 2-2.5 degrees C. Vitamin C administered alone and in combination with vitamin E reduced the fall in ulnar nerve conduction velocity. Prior supplementation with vitamin C and E could help ameliorate the impairment in human ulnar nerve conduction due to hypothermia.

Blood gases, hematology, and renal blood flow during prolonged mountain sojourns at 3500 and 5800 m.

BACKGROUND: This study mainly focused on renal blood flow, hematological parameters, blood gases, and blood pH, which are affected on exposure to moderate (3500 m) and extreme altitudes (5800 m) in sea level residents. HYPOTHESIS: Acute and prolonged exposure to high or extreme altitude may cause pathophysiological changes in kidney and renal plasma/blood flow, leading to retention of fluids in the tissues. Combined with the decreased availability of oxygen to the tissues, these may be responsible for high altitude maladies. METHOD: Fifteen male sea level (SL) volunteers, 22-25 yr old, were studied for blood gases, blood viscosity, hematocrit, hemoglobin concentration, and effective renal blood/plasma flow at Delhi (260 m), 3500 m (60 d stay), 5800 m (70 d stay), and 7 d after return to SL. RESULTS: Compared with SL, a significant increase from 7.34 to 7.43 (p < 0.01) in blood pH was observed at 3500 m that remained significantly increased at 5800 m. PO2 was about 39% less at 5800 m than at SL. PCO2 reduced significantly from 42.07 to 28.05 mm Hg on return from 5800 m to SL. The blood viscosity increased significantly (38%) at 5800 m and decreased significantly by 38% (p < 0.01) after return to SL. The effective renal plasma flow reduced significantly (p < 0.01) from 615.6 at SL to 381.5 ml x min(-1) x 1.73 m(-2) at 5800 m. CONCLUSION: The study suggests a crucial role of renal function in the acclimatization process; renal function also appears to be one factor by which the body protects itself against severe hypoxia.

Association of high-altitude systemic hypertension with the deletion allele-of the angiotensin-converting enzyme (ACE) gene.

People who visit high-altitude areas are exposed to a stressful environment and a good percentage of them suffer from high-altitude-induced diseases, including systemic hypertension. Identification of genetic markers for high-altitude-induced diseases would help to reduce the rate of morbidity/mortality from such diseases. The development of systemic hypertension on exposure to high altitude (3,500 m) for 30 days in otherwise normotensive natives of low-altitudes was investigated. The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) genotypes and renin-angiotensin-aldosterone system were simultaneously studied. In the hypertensives during their stay at high altitude, the ACE D allele frequency was significantly higher than in the normotensives (0.67 versus 0.32 chi(2)(1) = 10.6, P < 0.05). In the normotensives during their stay at high altitude, there was no significant increase in plasma aldosterone levels despite increased plasma renin activity. Results of the present study suggest that environmental changes and pre-existing genetic factors, namely the ACE D allele, might be two of the factors predisposing natives of low altitudes to systemic hypertension, a polygenic disease, at high altitude.

Cytoprotective activity of Amla (Emblica officinalis) against chromium (VI) induced oxidative injury in murine macrophages.

The cytoprotective and immunomodulating properties of Emblica officinalis (Amla) against chromium (VI) induced oxidative damage are reported. Chromium (VI) at 1 micro g/mL concentration was highly cytotoxic. It enhanced free radical production and decreased reduced glutathione (GSH) levels and glutathione peroxidase (GPx) activity in macrophages. The presence of Amla resulted in an enhanced cell survival, decreased free radical production and higher antioxidant levels similar to that of control cells. Further, chromium (VI) treatment resulted in decreased phagocytosis and gamma-interferon (gamma-IFN) production while Amla inhibited chromium induced immunosuppression and restored both phagocytosis and gamma-IFN production by macrophages significantly.

Oxygen saturation response to exercise VO2 at 2100 m and 4350 m in women mountaineering trainees.

Human work performances decreases at high altitude (HA). This decrement does not appear to be similar for every individual, may be due to variety of factors like elevation, mode of induction, work intensity, physical condition and specificity of the subjects. The purpose of the study was to evaluate the effects of alteration in responses of oxygen saturation (SaO2) and oxygen consumption (VO2) to a standard exercise in women mountaineering trainees under hypobaric hypoxia. Experiments were conducted in 2 groups (10 each) of females and compared the difference in responses of native women of moderate altitude with those of the plains/low altitude. A standard exercise test (Modified Harvard Step-Test for women) was performed on a 30 cm stool with 24 cycles/min for 5 min, initially at 2100 m and then at 4350 m. The exercise VO2 values for plains dwelling women achieved apparently VO2max level at both altitude locations with significant reduction in SaO2 during standard exercise. Exercise VO2 values decreased on exposure to 4350 m with further reduction in SaO2. Whereas with same work intensity, under same situation the exercise VO2 values of the moderate altitude women did not appear to have reached VO2max. They also maintained comparatively higher level of SaO2. It may be concluded that hypoxic exposure along with mountaineering training, the moderate altitude women maintained a higher level of SaO2 during standard exercise at both altitude locations, compared to low altitude women who might have lost a compensatory reserve to defend the hypoxic stress to exercise. Thus, moderate altitude women are proved to be better fit for hypoxic tolerance/HA performance.

Effect of high altitude (HA) on event related brain potentials.

Event Related brain potentials (ERPs) were recorded in 15 subjects using standard auditory odd ball paradigm, in which subjects were presented a sequence of two distinguishable sound stimuli of that occurred frequently (frequently (frequent stimulus-non target) and the other infrequently (rare stimulus-target). These recordings were made at sea level (SL) and then the subjects were air lifted to 3500 m altitude (HA), where they stayed for 3 weeks. Their ERPs were recorded during the first and third week of stay at HA and on return to sea level (RSL). Data indicated impairment in cognitive function as a result of exposure to HA as depicted by increase in the latency of P3 which was significant during the 1st week of stay at HA compared to sea level. The P3 wave latency during the 3rd week of stay at HA showed an increase compared to SL but was not statistically significant. From the results it may be concluded that high altitude hypoxia induced slow processing of stimulus evaluation, may be responsible for increase in P3 latency. The difference in the latent period of P3 waves during the first and third week of stay at HA may be due to continuous stay at HA which might lead to the time dependent adaptive processes occurring with increasing duration of exposure to HA which may induce learning effects.

Dimensional statistics for estimation of lung volumes.

The theory of dimension has been widely used in physics to check the validity of formulae. This theory has not been used more frequently in statistics as compared to physics for development of various prediction formulae/equations in applied physiology. An attempt has, therefore, been made in the present investigation to evolve formulae for estimation of lung volumes from cubic function of height based on dimensional considerations in boys and girls 8-13 and 16-21 years of age.

Brainstem auditory evoked responses in young urban and rural boys--a comparison.

Brainstem auditory evoked responses (BAER) were studied in a total of 194 boys in the age group between 10-15 yrs taken from a busy metropolitan city and also from a relatively quiet town in order to compare their values and to look into the probable cause of the difference between them, if any. BAER were tested with the help of Compact-4 (Nicolet, USA) instrument using the standard technique. In general, the BAER values of the two sample populations were found to be almost similar with no gross differences in terms of peak latency and inter peak latencies. The values were found to be comparable to adult male values as reported earlier.

Glucocorticoids as prophylaxis against acute mountain sickness.

OBJECTIVE: Acute mountain sickness (AMS) characterized by presence of symptoms including headache, nausea, excessive fatigue, loss of appetite, irritability and insomnia is a major impediment to work performance in human subjects who are rapidly inducted to high altitude (HA) during the initial phase of induction. The present study aims at to evaluate the efficacy of prophylactic administration of low dose glucocorticoids in prevention of AMS in normal healthy men who are inducted to HA by air. DESIGN: Fifty healthy men were randomly divided into five groups of 10 each. Group I received prednisolone (Pred) 10 mg, Group II Pred 20 mg, Group III Pred 40 mg, Group IV dexamethasone 0.5 mg, Group V received placebo once a day in the morning for 2 days at sea level (SL) and for 3 days on arrival at an altitude of 3450 m by air. MEASUREMENTS: The severity of AMS was assessed using Lake Louise AMS scoring system. Physiological parameters like blood pressure, respiratory rate, peripheral blood O2 saturation and heart rate were measured at sea level and on arrival at HA. Circulatory levels of cortisol and adrenocorticotropic hormone (ACTH) were measured by radioimmunoassay (RIA) and immunoradiometreic assay (IRMA), respectively. RESULTS: In the placebo group, significant AMS could be detected at 12 h of arrival at HA, peaked by day 1 or 2 of stay and started declining thereafter. As compared to the placebo group, the steroid treated groups showed a significant (P < 0.01) reduction in daily AMS score. When compared with prednisolone 10 mg, 40 mg and dexamethasone groups, the prednisolone 20 mg group showed an optimal response in reduction of AMS symptoms. The O2 saturation showed a significant decline (P < 0.001) on arrival at HA, but the pattern of O2 saturation in placebo and glucocorticoid groups was identical. Similarly, the rise in heart rate and blood pressure and on day 3 of stay at HA was similar in placebo and glucocorticoid-treated groups. An increase in plasma cortisol in placebo group was observed on day 3 of stay at HA and continued to rise till day 8 of observations. The cortisol levels in Pred 10 mg and Pred 20 mg groups on day 1 and 3 of arrival at HA were not significantly different than the SL post-treatment values but were found to be significantly higher on day 8 of stay. Plasma cortisol in Pred 40 mg and dexamethasone groups was significantly lower (P < 0.01) on day 1 and 3 of stay but showed an increase by day 8 of stay. The ACTH levels were increased at HA in placebo group but did not show any significant change till day 3 of stay in steroid treated subjects and were found to be higher in all groups on day 8 of observations. CONCLUSION: These observations suggest that administration of low-dose glucocorticoids can curtail acute mountain sickness significantly without influencing the normal adreno cortical response to hypoxia.

Effect of a carbohydrate supplement on feeding behaviour and exercise in rats exposed to hypobaric hypoxia.

The effect of a carbohydrate supplement, offered as a diet option, on feeding behaviour, body weight gain, and endurance exercise was studied in rats exposed to hypobaric hypoxia. Male albino rats (n = 35) were randomly divided into 5 groups; hypoxic supplemented and control groups; normoxic supplemented and control groups, and an untreated control group. After treadmill training for 5 days, the hypoxic groups were exposed to simulated high altitude equivalent to 6960 m for 18 days continuously. Food and water intakes, body weight and endurance exercise were recorded before and during the exposure period. Blood glucose, insulin, muscle and liver glycogen were assayed at the end of the exposure period. Hypobaric hypoxia resulted in a significant decrease in food and water intake, and body weight, and reduced endurance exercise capacity compared to the basal and normoxic group values. The carbohydrate supplement did not ameliorate the hypoxia-induced loss in body weight, but however, significantly delayed the onset of fatigue during exercise in the supplemented rats compared to the hypoxic control group.

Hypothalamic-pituitary-adrenal axis following glucocorticoid prophylaxis against acute mountain sickness.

The pituitary-adrenocortical and adrenomedullary response to high altitude (HA) stress was studied following daily single dose administration of prednisolone as a prophylaxis against altitude-induced acute mountain sickness (AMS). Forty healthy men, randomly divided into two groups of twenty, received placebo or prednisolone 20 mg once a day at 08.00 h for two days prior to induction to HA and during an initial three days stay at an altitude of 3450 m. The AMS score and circulatory levels of ACTH, cortisol, epinephrine and norepinephrine were measured at sea level (SL) and during residency at HA. The sensitivity of the hypothalamic-pituitary-adrenal axis in subjects receiving prednisolone therapy was evaluated at SL and on day four of stay at HA. Administration of prednisolone significantly (p < 0.01) decreased the severity of AMS in all the subjects. The steroid dose used did not inhibit endogenous secretion of ACTH, cortisol, epinephrine or norepinephrine, as HA response to adrenocortical and adrenomedullary hormones was identical in placebo and prednisolone treated subjects. The integrity of the hypothalamic-pituitary-adrenal axis was maintained well in subjects receiving low dose prednisolone therapy. These observations suggest that short-term administration of prednisolone is able to curtail AMS without causing suppression of the hypothalamic-pituitary-adrenal axis.

Sleep and performance--recent trends.

Sleep and sleep deprivation are intimately related to performance. Sleep management of people working in different sectors of the society like multi shift workers, nurses, doctors, students in professional schools and the armed forces has a great bearing on performance, health and safety of the subject population. The detrimental effects of sleep deprivation on psychological performance are indicated as increased lapsing, cognitive slowing, memory impairment, decrease in vigilance and sustained attention and shift in optimum response capability. Its effects on physical performance are manifested as decline in ability to perform maximal exercise, self-selected walking pace and increase in perceived exertion. Sleep deprivation appears to have no effect in respect of muscle contractile properties and maximum anaerobic power. At high altitude (HA), there is a reduction in NREM sleep with frequent awakening due to hypoxia as a physiological adaptive measure to prevent accentuation of hypoxemia due to sleep-hypoventilation. Total sleep deprivation for 48 hours at high altitude can affect the acclimatization status, thermoregulation efficiency and cognitive functions. The concept of 'sleepiness' has also been studied, as it is an emerging concept for better understanding of the effects of sleep deprivation and its effects on performance. A special mention of sustained operations in the armed forces has been made keeping in mind its uniqueness in challenging the normal sleep-work schedule and its deployment in extreme environment and operational condition. This article reviews in detail the functions of sleep, its requirement and the effects of sleep deprivation on human performance.

Cyto-protective and immunomodulating properties of Amla (Emblica officinalis) on lymphocytes: an in-vitro study.

The fruits extracts of Emblica officinalis (Amla) has been reported to have strong anti-oxidant properties. There is a paucity of studies on the immunomodulatory properties of fruit extracts of Amla in immuno-compromised states, with the emphasis on lymphocytes. Therefore, the aim of the study was to determine the anti-oxidant and immunomodulatory properties of Amla using chromium (VI) as an immunosuppressive agent. Chromium (Cr) treatment results in enhanced cytotoxicity, free radical production, lipid peroxidation and decreased glutathione peroxidase (GPx) activity and diminished glutathione (GSH) levels. There was a significant inhibition of both lipopolysaccharide and concanavalin-A-stimulated lymphocyte proliferation. Chromium also inhibited Con A stimulated interleukin-2 and gamma-interferon production significantly. Further, there was enhanced apoptosis and DNA fragmentation in the presence of Cr. Amla significantly inhibited Cr-induced free radical production and restored the anti-oxidant status back to control level. Amla also inhibited apoptosis and DNA fragmentation induced by Cr. Interestingly, Amla relieved the immunosuppressive effects of Cr on lymphocyte proliferation and even restored the IL-2 and gamma-IFN production considerably.