Temporal changes in the skin Malassezia microbiota of members of the Japanese Antarctic Research Expedition (JARE): A case study in Antarctica as a pseudo-space environment.

The International Space Station (ISS) is located approximately 400 km above the Earth. Astronauts staying at the ISS are under microgravity and are thus unable to bathe or shower; instead, they wash their bodies using wet tissues. For astronauts, skin hygiene management is important to maintain the quality of life during long-term stays on the ISS. In Antarctica, members of a Japanese geological investigation team negotiate their way over land using snowmobiles. During their 3-month stay, they are subject to a "pseudo-space" environment similar to that experienced by ISS astronauts, including the inability to bathe or shower. In this study, temporal changes in the colonization levels of skin lipophilic fungi, Malassezia were investigated in 16 team members. Compared to the levels before their trip to Antarctica, the fold changes in Malassezia colonization levels during the researchers' stay in Antarctica were in the range of 3.0 ± 1.9 to 5.3 ± 7.5 in cheek samples, 8.9 ± 10.6 to 22.2 ± 40.0 in anterior chest samples, 6.2 ± 5.4 to 16.9 ± 25.5 in behind-the-ear samples, and 1.7 ± 0.9 to 17.4 ± 33.4 in sole-of-the-foot samples. On the scalp, the level of Malassezia colonization increased dramatically, by 96.7 ± 113.8 to 916.9 ± 1251.5 fold. During their stay in Antarctica, the team members experienced itchy scalps and produced a large number of scales. The relative proportions of Malassezia globosa and M. restricta shifted to seborrheic dermatitis/dandruff types. These results provide useful information for the development of skin hygiene management plans for astronauts staying at the ISS.

Effect of microgravity on spatial orientation and posture regulation during Coriolis stimulation.

OBJECTIVE: To elucidate spatial orientation and posture regulation under conditions of microgravity. MATERIAL AND METHODS: Coriolis stimulation was done with five normal subjects on the ground (1 g) and onboard an aircraft (under conditions of microgravity during parabolic flight). Subjects were asked to tilt their heads forward during rotation at speeds of 0, 50, 100 and 150 degrees/s on the ground and 100 degrees/s during flight. Body sway was recorded using a 3D linear accelerometer and eye movements using an infrared charge-coupled device video camera. Flight experiments were performed on 5 consecutive days, and 11-16 parabolic maneuvers were done during each flight. Two subjects boarded each flight and were examined alternately at least five times. RESULTS: Coriolis stimulation at 1 g caused body sway, nystagmus and a movement sensation in accordance with inertial inputs at 1 g. Neither body sway, excepting a minute sway due to the Coriolis force, nor a movement sensation occurred in microgravity, but nystagmus was recorded. CONCLUSIONS: Posture, eye movement and sensation at 1 g are controlled with reference to spatial coordinates that represent the external world in the brain. Normal spatial coordinates are not relevant in microgravity because there is no Z-axis, and the posture regulation and sensation that depend on them collapse. The discrepancy in responses between posture and eye movement under conditions of microgravity may be caused by a different constitution of the effectors which adjust posture and gaze.

Decreased platelet level in peripheral blood of mice by microgravity.

It is reported that the stay in the space develop anemia, throbocytopenia, and altered function and structure of red blood cell. The mechanism of these abnormalities was not clarified yet. TPO has been shown to stimulate both megakaryocyte colony growth from marrow progenitor cells and the maturation of immature megakaryocyte to form functional platelet. This process include massive cytoskeletal rearrangement, such as proplatelet formation and fragmentation of proplatelet. Our previous reports (Fuse and Sato, 2001, Fuse et al, 2001) showed an inverse relationship between decreased platelet count and increased TPO concentrations in peripheral blood of mouse was induced by parabolic flight (PF). We have studied which gravity change during PF involved this phenomenon.