Cassava (Manihot esculenta Crantz), a widely used common vegetable of Indian origin contains dietary goitrogens. Goitrogenic content, in vitro anti-thyroidal activity and in vivo antithyroid potential of fresh and cooked cassava of Indian origin in albino rats with and without iodine supplementation were evaluated in this study. In vitro inhibition of thyroid peroxidase (TPO )activity was found with fresh and cooked cassava extract but the presence of extra iodide in the incubation media had shown reduction in such inhibition to an extent. Inhibition constant (IC 50 ) and PTU equivalence of fresh cassava were 42.5 ± 1.35µg and 2.21 respectively. After consumption, cyanogenic constituents in cassava are metabolized to thiocyanate and iodine-retaining capacity seems to be dependent on thiocyanate exposure. In cassava fed rats, the urinary iodine concentration resembled the state of adequate iodine nutriture but thyroid gland fails to utilize available iodine. Increased thyroid weight (P < 0.001), inhibited thyroid peroxidase (TPO) activity and reduced thyroid hormone profiles (P < 0.001) were noted in fresh and cooked cassava fed rats, resembling a relative state of morphological as well as biochemical hypothyroidism even in presence of adequate iodine.

A group of 221 male healthy volunteers of Indian Army were the subjects of the study. The baseline parameters of skeletal health were measured during their residency at an altitude of 3542 m. These subjects were then taken to an extreme altitude (EA, 5400-6700 m) where they stayed for about 4 months. The study parameters were repeated following their de-induction (DI) to 3542 m. On random selection, a subgroup was constituted from the above mentioned volunteers for detailed investigations on various bone turnover markers. Results of this study indicate a loss of body weight after DI from EA. The bone impairment was detected at the proximal phalanx, which is known to undergo early morpho-structural changes associated with bone resorption. The intact parathyroid hormone (i-PTH) levels showed a significant increase, while alkaline phosphatase (ALP) and bone specific alkaline phosphatase (BAP) activities declined significantly after DI from EA. This elevation in i-PTH might be required for maintenance of blood Ca level. 25 (OH) Vitamin D3 (25VitD) and calcitonin (CT) also showed a significant decline, which may suggest a negative impact on bone formation during sojourn at EA. The causes of deterioration of skeletal health at EA although are poorly understood but may be due to acute hypoxemia arising from extreme hypobaric hypoxia prevalent at extreme altitude.

These observations suggest that prolonged residency under hypoxic environment is associated with a decline in both bone formation and bone resorption markers, reflecting a lower bone turnover at HA.

Exaggerated pulmonary pressor response to hypoxia is a pathgonomic feature observed in high altitude pulmonary edema (HAPE) susceptible mountaineers. It was investigated whether measurement of basal pulmonary artery pressure (Ppa) and brain natriuretic peptide (BNP) could improve identification of HAPE susceptible subjects in a non-mountaineer population. We studied BNP levels, baseline hemodynamics and the response to hypoxia (FIo2 = 0.12 for 30 min duration at sea level) in 11 HAPE resistant (no past history of HAPE, Control) and 11 HAPE susceptible (past history of HAPE, HAPE-S) subjects. Baseline Ppa (19.31 ± 3.63 vs 15.68 ± 2.79 mm Hg, p < 0.05) and plasma BNP levels (52.39 ± 32.9 vs 15.05 ± 9.6 pg/ml, p < 0.05) were high and stroke volume was less (p < 0.05) in HAPE-S subjects compared to control. Acute hypoxia produced an exaggerated increase in heart rate (p < 0.05), mean arterial pressure (p < 0.05) and Ppa (28.2 ± 5.8 vs 19.33 ± 3.74 mm Hg, p < 0.05) and fall in peripheral oxygen saturation (p < 0.05) in HAPE-S compared to control. Receiver operating characteristic (ROC) curves showed that Ppa response to acute hypoxia was the best variable to identify HAPE susceptibility (AUC 0.92) but BNP levels provided comparable information (AUC 0.85). BNP levels are easy to determine and may represent an important marker for the determination of HAPE susceptibility.

Imperishable research work was done on females visiting high-altitude (HA) areas for recreational activities or job purposes as well as on female HA natives. Hypoxia at HA is an unavoidable condition that affects the determinants of female reproductive functions like, the age of menarche and menopause, whole reproductive span, hormone synthesis, and fertility. This review will emphasize whether HA hypoxia is a threat to women: residents or visitors by analyzing these proximate determinants. Delayed menarcheal and advanced menopausal age was found to shorten the reproductive span in some HA populations, whereas in some cases, menstrual cycle was also reported to be irregular. In addition, the completed fertility rate (CFR) was increased when people migrated to lower altitude. Altered stress hormones and reproductive hormones were observed in sea-level females exposed to HA. Oxidative stress (OS) at HA was also reviewed to explain the probable reasons for the observed changes in these determinants because disturbed redox homeostasis may be a connecting link, affecting the reproductive functions. In conclusion, HA hypoxia plays a crucial role on various determinants of female reproductive health and this review will be helpful for more precise study along with the probable underlying mechanisms responsible for the changes in female reproductive functions at HA.