Search PubMed⌕ Search

Biomedical subjects

K Sridharan

Publications and source records attributed to K Sridharan.

27 records · Page 2Linked to original sources
PubMed1977

Study of the pituitary-thyroid functions at high altitude in man.

The alterations in serum levels of T3, T4, TSH and TBG, TSH response to 100 mug iv TRH, and urinary excretion of T3 and T4 were studied in 8 healthy men at sea level (SL), on days 1, 2, 4, 8 and 16 after arrival by air at high altitude (3,700 m, HA), and during days 5 to 7 after their return to SL. No significant alterations in serum levels of TSH and TBG or TSH response to TRH were observed during exposure to HA or on return to SL. There was, however, an acute elevation in both serum total T3 and T4. Serum total T3 from a mean basal+/-SE value of 128+/-13 ng/dl increased to 320+/-18 on day 1 and remained significantly elevated at 225+/-48 up to day 8 after arrival at high altitude. Similarly serum total T4 increased from basal level of 9+/-0.92 mug/dl to 15.2+/-1.2 and remained elevated till day 16 and it was 11+/-1.19 mug/dl during days 5 to 7 after return to SL. The urinary excretion of both T3 and T4 was decreased. These changes perhaps were the result of complex physiologic adjustments on acute exposure to high altitude, like shrinkage of the T3 and T4 distribution pools, altered binding capacities of thyroid hormones binding proteins, and a reduction in clearance of thyroid hormones from the plasma compartment; and were probably not suggestive of an enhanced thyroid activity. Their actual significance in high altitude adaptation in man is not clearly understood.

Adult↗
PubMed1976

Food intake and energy expenditure of Indian troops in training.

1. Food intake and energy expenditure were determined on 500 soldiers drawn from infantry, artillery and engineer units of the Indian army, for 3 months during winter. 2. The units were located in two different regions of India at altitudes varying from sea level to 2300 m. 3. The energy requirements were assessed from the actual food intake as well as from energy expenditure and from the changes in body-weight and skinfold thickness. 4. The nutritional adequacy of the diet was assessed from clinical examination and changes in blood haemoglobin concentration. 5. The mean energy expenditure was found to be 15-39 MJ (3679 kcal) and on this basis the energy requirements was 16-61 MJ (3970 kcal); energy intake was found to be 16-47 MJ (3936 kcal). 6. The energy contributed by protein, fat and carbohydrate was 0-115, 0-240 and 0-645 of the total intake respectively. 7. There was no significant change in body-weight, blood haemoglobin level and skinfold thickness on this mean daily intake.

Altitude↗
PubMed1976

Potassium losses in sweat under heat stress.

Six healthy, heat-acclimatized subjects were exposed to different hot and humid environments in a climatic chamber and sodium, potassium, and chloride concentrations in their sweat, urine, and blood were determined. The concentration of potassium in sweat was found to be considerably higher than that in the plasma, whereas that of sodium and chloride was very much lower. The concentration of potassium in urine was also 8-12 times higher than that in the plasma as compared to 0.5 to 1.5 times higher for sodium and chloride. The total daily computed losses of potassium in sweat and urine, of a person working in severe heat in the tropics, can be about 116 mEq as against a dietary intake of 97 mEq/d, thereby resulting in negative potassium balance. The potassium depletion in sweat, even in acclimatized Indians, is thus heavy and is likely to play an important role in the causation of heat-illness.

Acclimatization↗
PubMed1975

Glucose tolerance of lowlanders during prolonged stay at high altitude and among high altitude natives.

The fasting blood sugar level and glucose tolerance were investigated in seven amle lowlanders at sea level, during their stay at an altitude of 4,000 m at intervals of 2 weeks, 10, 15, 20, and 24 months and again on return to sea level during the first week and after 1 month. For comparison, the glucose tolerance of six male Ladakhis (natives of high altitude area) was also determined at altitude. The fasting blood sugar among lowlanders increased to 136.0 plus or minus 4.39 mg per 100 ml during 10 months of stay at altitude followed with a gradual decrease to a value of 76.4 plus or minus 3.8 at the end of 24 months. On return to sea level, the blood glucose showed a tendency to increase. Ladakhis had a lower blood sugar level at altitude (86.4 plus or minus 7.28) as compared with lowlanders at sea level (92.6 plus or minus 2.29). The glucose tolerance curves of lowlanders ran paralell to each other at altitude and at sea level. However, the peak of the glucose tolerance curve shifted towards the left during the 20th and 24th months of stay at altitude and at sea level. However, the peak of the glucose tolerance curve shifted towards the left during the 20th and 24th months of stay at altitude and on return to sea level. The tolerance curve of Ladakhis was similar to that of lowlanders at altitude, but showed a sharper blood sugar decline rate.

Acclimatization↗
PubMed1975

Electrolyte changes at 3500 m in males with and without high-altitude pulmonary edema.

Ten normal healthy male subjects between 20-30 years of age were initially examined at Delhi (200 m) and thereafter air-lifted to an altitude of 3,500 m. Excretion of sodium, potassium and chloride in urine and their plasma level were determined at sea level (SL) and daily at high altitude (HA) for 4 d. At HA, four subjects developed high-altitude pulmonary edema (HAPE), four remained normal, and two suffered from acute mountain sickness. The results on normals and HAPE are presented. There was increased excretion of potassium at HA in both groups resulting in reduction of plasma level. The sodium and chloride excretion was also increased in normals at HA irrespective of urine volume. In HAPE cases, the sodium and chloride excretion was related to urine output. With the retention of fluid, the excretion of these ions in urine was diminished without a parallel change in plasma levels.

Adult↗