Static and dynamic hypergravity responses of osteoblasts and osteoclasts in medaka scales.

Fish scales are a form of calcified tissue similar to that found in human bone. In medaka scales, we detected both osteoblasts and osteoclasts and subsequently developed a new scale assay system. Using this system, we analyzed the osteoblastic and osteoclastic responses under 2-, 3-, and 4-gravity (G) loading by both centrifugation and vibration.

Prostaglandin E₂ increases both osteoblastic and osteoclastic activity in the scales and participates in calcium metabolism in goldfish.

Using our original in vitro assay system with goldfish scales, we examined the direct effect of prostaglandin E₂ (PGE₂) on osteoclasts and osteoblasts in teleosts. In this assay system, we measured the activity of alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) as respective indicators of each activity in osteoblasts and osteoclasts. ALP activity in scales significantly increased following treatment at high concentration of PGE₂(10⁻⁷ and 10⁻⁶ M) over 6 hrs of incubation.

Expression of p53-regulated proteins in human cultured lymphoblastoid TSCE5 and WTK1 cell lines during spaceflight.

The aim of this study was to determine the biological effects of space radiations, microgravity, and the interaction of them on the expression of p53-regulated proteins. Space experiments were performed with two human cultured lymphoblastoid cell lines: one line (TSCE5) bears a wild-type p53 gene status, and another line (WTK1) bears a mutated p53 gene status. Under 1 gravity or microgravity conditions, the cells were grown in the cell biology experimental facility (CBEF) of the International Space Station for 8 days without experiencing the stress during launching and landing because the cells were frozen during these periods.

Frozen human cells can record radiation damage accumulated during space flight: mutation induction and radioadaptation.

To estimate the space-radiation effects separately from other space-environmental effects such as microgravity, frozen human lymphoblastoid TK6 cells were sent to the "Kibo" module of the International Space Station (ISS), preserved under frozen condition during the mission and finally recovered to Earth (after a total of 134 days flight, 72 mSv). Biological assays were performed on the cells recovered to Earth. We observed a tendency of increase (2.

p53-dependent adaptive responses in human cells exposed to space radiations.

Purpose: It has been reported that priming irradiation or conditioning irradiation with a low dose of X-rays in the range of 0.02-0.1 Gy induces a p53-dependent adaptive response in mammalian cells.

The expression of p53-regulated genes in human cultured lymphoblastoid TSCE5 and WTK1 cell lines during spaceflight.

Purpose: The space environment contains two major biologically significant influences; space radiations and microgravity. The 53 kDa tumour suppressor protein (p53) plays a role as a guardian of the genome through the activity of p53-centered signal transduction pathways. The aim of this study was to clarify the biological effects of space radiations, microgravity, and the space environment on the gene expression of p53-regulated genes.

Detection of space radiation-induced double strand breaks as a track in cell nucleus.

To identify DNA damage induced by space radiations such as the high linear energy transfer (LET) particles, phospho-H2AX (gammaH2AX) foci formation was analyzed in human cells frozen in an International Space Station freezer for 133days. After recovering the frozen sample to the earth, the cells were cultured for 30 min, and then fixed. Here we show a track of gammaH2AX positive foci in them by immuno-cytochemical methods.

Monohydroxylated polycyclic aromatic hydrocarbons inhibit both osteoclastic and osteoblastic activities in teleost scales.

Aims: We previously demonstrated that monohydroxylated polycyclic aromatic hydrocarbons (OHPAHs) bound to a human estrogen receptor (ER) by a yeast two-hybrid assay, but polycyclic aromatic hydrocarbons did not have a binding activity. Therefore, the direct effect of 3-hydroxybenz[a]anthracene (3-OHBaA) and 4-hydroxybenz[a]anthracene (4-OHBaA) on osteoclasts and osteoblasts in teleosts was examined. As a negative control, 1-hydroxypyrene (1-OHPy), which has no binding activity to human ER, was used.

DNA damage recognition proteins localize along heavy ion induced tracks in the cell nucleus.

To identify the repair dynamics involved in high linear energy transfer (LET) radiation-induced DNA damage, phospho-H2AX (gammaH2AX) foci formation was analyzed after cellular exposure to iron ions (Fe-ions, 500 MeV u(-1), 200 KeV microm(-1)). The foci located at DNA damage sites were visualized using immunocytochemical methods. Since H2AX is phosphorylated at sites of radiation-induced double strand breaks (DSB), gammaH2AX foci were used to detect or illuminate tracks formed by DSB after exposure to various doses of ionizing radiation.

An overview of challenges in modeling heat and mass transfer for living on Mars.

Engineering a life-support system for living on Mars requires the modeling of heat and mass transfer. This report describes the analysis of heat and mass transfer phenomena in a greenhouse dome, which is being designed as a pressurized life-support system for agricultural production on Mars. In this Martian greenhouse, solar energy will be converted into chemical energy in plant biomass.