Relationship between stress hormones and immune response during high-altitude exposure in women.

We previously confirmed that high altitude (HA) exposure can modify the number and function of immune cells, leading to a disruption in the homeostatic regulation of T helper1 (Th1)/T helper2 (Th2) immune responses. Our aim was to evaluate possible relationships between the stress response and immunological parameters during HA exposure. Thirteen healthy women spent 21 days at 5050 m. Before (SL1), the first and the 21st day at HA (HA1 and HA2, respectively), and the day after returning at sea level (SL2), we collected blood samples for immunologic parameters, and 24-h urine samples for norepinephrine, epinephrine, and cortisol. Norepinephrine and cortisol significantly increased (p<0.01) at HA1 and HA2 compared to SL1, while epinephrine did not change. At HA1, CD3+ T-cell fell significantly (p<0.001) with respect to SL1, owing to a significant (p<0.001) CD4+ T-cell reduction, while CD16+ and CD56+ increased (p<0.001) at HA2 compared to SL1. The expression of interferon-gamma (IFN-gamma) decreased (p<0.0005) at HA1 and HA2 with respect to SL1. At HA1 different lymphocyte subset (CD3+, CD4+, CD19+) were well correlated with epinephrine (p<0.05), whereas in analyzing the combined data (SL1-HA1-HA2-SL2), CD3+ (r=-0.310), CD4+ (r=-0.332), CD16+ (r=0.404), and CD56+ (r=0.373) demonstrated moderate but significant correlations (p<0.05) with norepinephrine. Moreover, norepinephrine levels were inversely correlated (r=-0.591; p<0.001) with IFN-gamma expression, a typical Th1 cytokine. We suggest that the sympatho-adrenal axis may have a role on the immunologic adaptations observed during HA exposure, and specifically on the observed impairment of the Th1/Th2 immune balance.

Delayed effect of nitric oxide synthase inhibition on the survival of rats after acute decompression.

AIM: The formation of bubbles in the blood stream together with the ensuing sickness after rapid decompression is assumed to depend on the physiological condition of the vascular system. In order to gain insight into the vascular function of nitric oxide in acute decompression sickness, the effects of the nitric oxide synthase inhibition by N(omega)-nitro-L-arginine methyl ester was studied in rats. METHODS: Wistar rats under anaesthesia were exposed to hyperbaric conditions for two hours and decompressed approximately 2.5 hours after a single subcutaneous injection of N(omega)-nitro-L-arginine methyl ester. Scalar doses and different pressures were tested. RESULTS: The fraction of the rats that died after decompression was greater in rats treated with N(omega)-nitro-L-arginine methyl ester at doses greater than 8 mg Kg-1 body weight compared to untreated rats. CONCLUSION: Although we have not excluded effects of nitric oxide synthase inhibition on distribution of perfusion and therefore inert gas elimination from tissue during decompression as a factor, this result highlights a delayed benefit of nitric oxide synthase activity in preventing death in acute decompression sickness.

[Effects of a combined weight-bearing and non-weight-bearing ( warm water) exercise program on bone mass and quality in postmenopausal women with low bone-mineral density]. / Effetti di un programma combinato di esercizio con e senza sovraccarico (acqua termale) sulla massa e qualità ossea in un gruppo di donne in età post-menopausale con deficit minerale osseo.

AIMS: To evaluate the effects of a combined weight- and non weight-bearing (water) exercise program on bone mass and quality in postmenopausal women with low bone mineral density. MATERIALS AND METHODS: 125 post-menopausal women with osteopenia/osteoporosis underwent a bone mass (Dual-Energy X-ray Absorbimetry, DEXA) and bone tissue quality (phalangeal osteosonography) evaluation. 58 of the participants took part in an 11-month specific exercise program (E). The other represented a control group (C) that did not exercise. At the end of the exercise program all the participants were re-evaluated. RESULTS: Concerning bone mass, within and between groups data analysis showed that t-score, measured at neck of femur, significantly increased in E (p < 0.05). No differences were instead detected for all the other parameters. With respect to osteosonography, group C showed a significant decrease of all bone quality parameters (p < 0.05), whereas E showed no differences after the exercise program. CONCLUSIONS: The results showed that a specific exercise program targeting osteoporosis is useful to reduce the physiological bone loss and to maintain a good bone quality in a group of postmenopausal women with low bone mineral density.

Short-term adapted physical activity program improves bone quality in osteopenic/osteoporotic postmenopausal women.

BACKGROUND AND AIMS: It is known that people affected by osteopenia/osteoporosis can benefit from an adequate amount of physical activity, counteracting the progressive loss of bone and muscle mass caused by aging. Moreover, there is increasing evidence that exercise has positive effects on bone structure. The aim of our study was to evaluate the effects on bone tissue and muscular strength of a short-term exercise program in osteopenic/osteoporotic postmenopausal women. METHODS: Forty-nine osteopenic/osteoporotic postmenopausal women were divided into 2 groups: exercise and control. All subjects underwent 2 evaluations: before and after a training period. Bone quality was assessed by phalangeal quantitative osteosonography, and maximal strength of leg extensor muscles was also evaluated. The experimental group participated in a specific supervised 20-week physical activity program that included aerobic, balance, and strength training. RESULTS: After the training period, all bone parameters and lower-limb maximal strength were significantly improved in the exercise group (P < .05), whereas no significant changes were observed in the control group. CONCLUSIONS: Our study showed that a broad-based training protocol, lasting 20 weeks, can improve leg strength and bone quality parameters-main determinants of fall and fracture risk, respectively.