Effect of nutritional rehabilitation on circulating ghrelin and growth hormone levels in patients with anorexia nervosa.

Circulating ghrelin and growth hormone (GH) are up-regulated in anorexia nervosa (AN) as a consequence of prolonged starvation. The current study examines the effect of nutritional rehabilitation with improvement of eating behavior on ghrelin and GH levels in AN patients during the course of inpatient treatment. The subjects included 34 female AN patients and 9 age-matched female controls. Fasting blood samples were collected before, during and after treatment. For data analysis, AN subjects were divided into three subtypes. The first group included seven patients with emergent hospitalization (E-AN), who were accompanied by severe emaciation due to their inability for food intake for more than a month. The other two groups included 14 AN with restricting (AN-R) and 13 AN with binge-eating/purging (AN-BP) patients. There were significant correlations between ghrelin, GH and body mass index (BMI) before treatment in all subjects. However, ghrelin levels were not significantly correlated with BMI and GH although there was a relationship between GH and BMI after treatment. Before treatment, E-AN patients had the highest levels of ghrelin and GH with the lowest glucose levels and liver dysfunction. The AN-BP group had a higher level of ghrelin than the AN-R group. During treatment, comparing with the controls group only the AN-R group showed higher level of ghrelin. Contrarily, the ghrelin levels in the E-AN group, who showed improved glucose levels, and the AN-BP group, who stopped vomiting behavior due to our treatment, decreased ghrelin levels. After treatment, only the AN-BP group showed a higher ghrelin level as compared to the controls. Although GH levels of the three AN groups decreased gradually according to our treatment progress, it still showed the higher value than the control group at the end of the treatment because every AN patients could not reach to more than 80% of their ideal body weight at discharge. These findings suggest that (1) severe emaciation with abnormal fasting hypoglycemia in AN patients may cause very high levels of GH and ghrelin, (2) that GH levels in AN patients may relate to nutritional status and (3) that ghrelin may be influenced by not only nutritional status but also the eating behavior of the patients.

The development of the International Space Station centrifuge.

Gravitational biology research facility "Centrifuge" is currently under development for the International Space Station. Research in the Complex Organism Biology, indispensable to the progress in Health Science, is only possible in the Centrifuge aboard the station. So, on-orbit 1 G controls for various specimens including small mammals, fish, and higher plants will be rigorously done in the Centrifuge. This facility is also capable of providing "reduced gravity" likely on the Moon or on Mars. Thus, it will play a key role in creating knowledge of space fundamental biology. As part of the offset of NASA's Shuttle launch services for the Japanese Experiment Module, JAXA is developing the Centrifuge Rotor (CR), the Life Sciences Glovebox (LSG) and the Centrifuge Accommodation Module (CAM). Critical Design Review (CDR) of LSG was conducted on July 2004, while the system CDRs of the CAM and CR are scheduled for December 2004 and August 2005, respectively. Their launch schedules are under review.

Dose equivalents inside the MIR Space Station measured by the combination of CR-39 plates and TLDs and their comparison with those on Space Shuttle STS-79, -84 and -91 missions.

In 1997, four dosimeter packages, each of which contains two CR-39 plates and 18 TLDs (Mg2SiO4:Tb), were placed inside the MIR Space Station and flew on an orbit with an inclination angle of 51.6 degrees and an altitude of approximately 400 km for 40 days. We estimated the absorbed doses, dose equivalents and effective quality factors during the flight by combining CR-39 data and TLD data. We then compared these results to those obtained with the same analysis method from the dosimeter packages on board Space Shuttle missions STS-79, -84 and -91 that flew along the same orbit. Finally, the differences between our results and those obtained by another group using passive dosimeters on the MIR are discussed.

Detection of DNA damage induced by space radiation in Mir and space shuttle.

Although physical monitoring of space radiation has been accomplished, we aim to measure exact DNA damage as caused by space radiation. If DNA damage is caused by space radiation, we can detect DNA damage dependent on the length of the space flight periods by using post-labeling methods. To detect DNA damage caused by space radiation, we placed fixed human cervical carcinoma (HeLa) cells in the Russian Mir space station for 40 days and in an American space shuttle for 9 days. After landing, we labeled space-radiation-induced DNA strand breaks by enzymatic incorporation of [3H]-dATP with terminal deoxyribo-nucleotidyl transferase (TdT). We detected DNA damage as many grains on fixed silver emulsion resulting from beta-rays emitted from 3H-atoms in the nuclei of the cells placed in the Mir-station (J/Mir mission, STS-89), but detected hardly any in the ground control sample. In the space shuttle samples (S/MM-8), the number of cells having many grains was lower than that in the J/Mir mission samples. These results suggest that DNA damage is caused by space radiation and that it is dependent on the length of the space flight.

Mutation frequency of plasmid DNA and Escherichia coli following long-term space flight on Mir.

To elucidate the biological influence of space radiation, we studied the effects of long-term space flight on mutation of the bacterial ribosomal protein L gene (rpsL). We prepared dried samples of plasmid DNA and repair-deficient and wild type cells of Escherichia (E.) coli. After a 40-day space flight on board the Russian space station Mir, the mutation frequencies of the rpsL gene were estimated by transformation of E. coli and by assessment of conversion of rpsL wild type phenotype (SmS) to its mutant phenotype (SmR). The experimental findings indicate that mutation frequencies of space samples were not significantly different from those of ground control samples in plasmid DNA and both E. coli strains. It may suggest that space radiation did not influence mutation frequency.