Evaluating Health Impact at High Altitude in Antarctica and Effectiveness of Monitoring Oxygen Saturation

[Background] The Japanese Antarctic Research Expedition (JARE) has been conducting research activities in inland Antarctica, which is extremely cold dryland covered with a thick ice sheet. This environment may cause a health disorder called acute mountain sickness (AMS). To improve the safety of expedition members, we evaluated the impact of extreme environmental conditions on human health and the effectiveness of monitoring of hypoxia for the early detection of AMS. [Methods] In total, 9 members from JARE 59 were studied. Dome Fuji Station (Dome F), located 3,810 m above sea level (ASL), was the destination of the research party. We analyzed daily AMS scores (higher values correspond to more severe AMS-related symptoms), physiological findings, and percutaneous arterial blood oxygen saturation (SpO2) during the inland activity. We also determined the factors related to AMS scores. [Results] The average AMS score on arrival at Dome F was significantly higher than that at the departure point (560 m ASL). The average SpO2 level was significantly lower than that at other points. The SpO2 level correlated negatively with the AMS score in Spearman’s rank correlation. Generalized estimating equations analysis showed that the AMS score was negatively associated with SpO2 level and positively associated with age. [Conclusion] Hypoxia is a contributory factor to AMS which we can easily assess by measuring the SpO2 level with a pulse oximeter. SpO2 monitoring is a potentially useful health management tool for members in inland Antarctic expeditions. In addition, our results are helpful for understanding physiological responses and health issues in extreme environments

Relationship between an Angiotensinogen Gene Polymorphism (M235T) and Serum Lipids: A Cross-Sectional Study among Japanese Workers

Angiotensinogen (AGT) is a component of the renin-angiotensin system, which plays a central role in blood pressure regulation. Although it is controversial, the association between AGT gene polymorphisms and hypertension, and coronary heart disease is suspected. In a case-control study on the metabolic syndrome, an association between AGT M235T polymorphism and serum total cholesterol (TC) level was demonstrated by Thomas et al. (2001). To reconfirm this relationship, a cross-sectional study among Japanese workers with 876 dyslipidemia and 1,158 non-dyslipidemia subjects was carried out. To evaluate the AGT M235T polymorphism, a PCR-mutant allele specific amplification (MASA) method was employed. No significant difference in the distribution of genetic variance was observed between the two groups. Although it was not significant, the T allele correlating to the lower TC of the present study occurred in a reversed manner to the previous report. In our results, no significant association between AGT M235T and TC was observed

Rescue from Stx2-Producing E. coli-Associated Encephalopathy by Intravenous Injection of Muse Cells in NOD-SCID Mice

Shiga toxin-producing Escherichia coli (STEC) causes hemorrhagic colitis, hemolytic uremic syndrome, and acute encephalopathies that may lead to sudden death or severe neurologic sequelae. Current treatments, including immunoglobulin G (IgG) immunoadsorption, plasma exchange, steroid pulse therapy, and the monoclonal antibody eculizumab, have limited effects against the severe neurologic sequelae. Multilineage-differentiating stress-enduring (Muse) cells are endogenous reparative non-tumorigenic stem cells that naturally reside in the body and are currently under clinical trials for regenerative medicine. When administered intravenously, Musecells accumulate to the damaged tissue, where they exert anti-inflammatory, anti-apoptotic, anti-fibrotic, and immunomodulatory effects, and replace damaged cells by differentiating into tissue-constituent cells. Here, severely immunocompromised non-obese diabetic/severe combined immunodeficiency (NOD-SCID) mice orally inoculated with 9 × 109 colony-forming units of STEC O111 and treated 48 h later with intravenous injection of 5 × 104 Muse cells exhibited 100% survival and no severe after-effects of infection. Suppression of granulocyte-colony-stimulating factor (G-CSF) by RNAi abolished the beneficial effects of Muse cells, leading to a 40% death and significant body weight loss, suggesting the involvement of G-CSF in the beneficial effects of Muse cells in STEC-infected mice. Thus, intravenous administration of Muse cells could be a candidate therapeutic approach for preventing fatal encephalopathy after STEC infection

Association between shift work and the risk of death from biliary tract cancer in Japanese men

Background: There is increasing evidence suggesting that shift work involving night work may increase cancer risk. Methods: We examined the association between working rotating shifts and the risk of death from biliary tract cancer among Japanese men who participated in the Japan Collaborative Cohort Study. Of the 46, 395 men recruited, 22, 224 men aged 40-65 at baseline (1988-1990) who reported working full-time or were self-employed were included in the present analysis. The study subjects were followed through December 31, 2009. Information regarding occupation and lifestyle factors was collected using a self-administered questionnaire. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95 % confidence interval (CI) for the risk of death from biliary tract cancer in relation to shift work. Results: During a mean 17-year follow-up, we observed 94 biliary tract cancer deaths, including 23 deaths from gallbladder cancer and 71 deaths from extrahepatic bile duct cancer. Overall, shift work was associated with a statistically non-significant increase in the risk of biliary tract cancer, with an HR of 1.50 (95 % CI: 0.81-2.77), among rotating shift workers. When the analysis was limited to extrahepatic bile duct cancer, a significant association appeared, with a multivariable-adjusted HR of 1.93 (95 % CI: 1.00-3.72) for rotating shift workers. Conclusion: Our data indicate that shift work may be associated with increased risk of death from extrahepatic bile duct cancer in this cohort of Japanese men. The association with gallbladder cancer remains unclear because of the small number of deaths

Sleep duration and risk of breast cancer : The JACC Study

PurposeThe evidence on beneficial or adverse effects of sleep duration on risk of breast cancer remains controversial and limited, especially in Asia.MethodsA prospective study of 34,350 women aged 40-79years in whom sleep duration, and menstrual and reproductive histories were determined by a self-administered questionnaire. The follow-up period was from 1988 to 2009, and hazard ratios (HRs) with 95% confidence intervals (CIs) of breast cancer incidence were calculated for shorter sleep duration in reference to sleep duration of 8h/day by Cox proportional hazard models.ResultsDuring 19.2-year median follow-up (236 cases), we found a significant inverse association between sleep duration and risk of breast cancer, especially among postmenopausal women and women with low parity (nulliparous and women with <3 children); the multivariable HRs (95% CIs) among postmenopausal women who reported 7h/day and 6h/day of sleep in reference to 8h/day were 1.49 (0.81-2.76) and 1.98 (1.08-3.70) (P for trend=0.028), respectively, and the corresponding values among women with low parity were 1.50 (0.96-2.35) and 1.76 (1.01-2.79) (P for trend=0.018).ConclusionsShort sleep duration was associated with increased risk of incident breast cancer, especially among postmenopausal women and women with low parity