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It is not clear whether blood hemoglobin concentration ([Hb]) increases with an increase in the exposure period of intermittent hypoxia (IHx) and reaches a constant level. Furthermore, it is not known whether plasma erythropoietin concentration ([EPO]) also increases with an increase in the exposure period. Using a rat model, first, we evaluated changes in [EPO] every hour after single exposure of 10% O(2) for 120 min in order to determine a peak level of [EPO]. Second, we evaluated the effect of IHx of 10% O(2), 120 min/day for 0 (control), 1, 2, 3, 4, 6 and 8 weeks on [Hb], arterial blood pressure (BP), heart rate (HR), arterial blood gases (ABGs) and [EPO]. [EPO] increased after cessation of the single hypoxic exposure, reached a peak at 1 h, and decreased gradually to the control levels within 18 h. IHx of 10% O(2), 120 min/day, produced a time-dependent increase in [Hb], and [Hb] reached a constant level after the exposure for 6 weeks. BP increased after the exposure for 4 weeks and remained elevated. There was no significant difference in HR and ABGs. [EPO] increased significantly and remained elevated at the same level for 1-3 weeks, however, the peak level of [EPO] declined markedly after [Hb] reached a constant level.

[Background] In patients with chronic obstructive pulmonary disease (COPD), early lactic acidosis during exercise should be considered as playing a role in the limitation of exercise tolerance. It was hypothesized that the relationship between blood lactate concentrations (LA) and tissue oxygenation index (TOI) is available for the prediction of aerobic capacity of skeletal muscle. [Methods] Changes of LA and TOI in the vastus lateralis muscle were measured during incremental cycling exercise in 12 healthy subjects and 4 patients with COPD. The relationship between TOI and LA was examined in 12 healthy subjects and 4 COPD patients, and changes in the relationship were examined at an interval of several years (3.3 +/- 1.0). [Results] (1) From the pattern LA as related to TOI, the healthy subjects were classified into the three groups. Group A (n = 3); LA increased slowly with a decrease in TOI. Group B (n = 3); LA increased steeply after the half point of maximal exercise. Group C (n = 6); LA increased steeply before the half point of maximal exercise. (2) In 3 patients with COPD, the relationship between TOI and LA shifted rightward at the second examination. [Conclusion] The steep increase in LA from the approximate resting value of TOI during exercise suggests that the aerobic capacity of working skeletal muscle decreased.

Background Smoking is known to be a serious risk factor for COPD, lung cancer and other chronic pulmonary diseases. The traditional custom in Erimo, Hokkaido is for the children to light a cigarette and hand it over to their parents whose hands were wet from fishing in 1940's. This study examined the influence of childhood passive smoke exposure with respiratory diseases. Aim We attempted to find the cause for severe COPD and other pulmonary diseases with early exposure to cigarette smoke. The prevalence of these diseases was analyzed in comparison with other areas in Japan. Methods We used results from routine medical checkup by Erimo city health division in which about 6000 residents' epidemiologic survey was performed. The statistical materials released from the Japanese government were used for comparison of each disease and mortality rate. Results Majority of smokers were found to be active or had passive exposure to tobacco smoke from a young age in Erimo. The housemate smoking rate was 81.0%. The mortality of chronic respiratory disease was 71.4 per 100,000 person-years, which was much higher than the national average (11.4 per 100,000 person-years). Prevalence of COPD (465.5 per 100,000 person-years) was higher than the national average (136.2 per 100,000 person-years). That of lung cancer was also very high (83.3 per 100,000 person-years). Conclusion The results of the present study suggest that early exposure to tobacco smoke produces chronic pulmonary diseases and lung cancer. In Japan, men's smoking rate had decreased, but the rate in women (9.1%) had steadily increased from 1989. Specifically the smoking rate in younger generation remains still high (14.3% aged 20's, 18.0% aged 30's). Further analysis of cohorts from Erimo would be a valuable indicator on the impact of smoking activities on lung health and disease.

HAPE (High Altitude Pulmonary Edema) is a serious and fatal disease in mountains. Early diagnosis and immediate descent are important for successful treatment. One of the authors (GS), who was healthy and a well trained climber, participated in the expedition to K2 (8611 m) in 2006 and developed HAPE. Under the severe environmental condition, it was difficult to evaluate his condition in its early stage. The earliest symptoms were nonspecific for HAPE as reported in many papers. Neither had he suffered from HAPE on the previous expeditions. These facts probably delayed the diagnosis in spite of its typical onset. This is a rare case report by a medical doctor who suffered from HAPE. The present case may remind the climbers of the difficulties in diagnosing HAPE on a mountain.