Atelocollagen-mediated local and systemic applications of myostatin-targeting siRNA increase skeletal muscle mass.

RNA interference (RNAi) offers a novel therapeutic strategy based on the highly specific and efficient silencing of a target gene. Since it relies on small interfering RNAs (siRNAs), a major issue is the delivery of therapeutically active siRNAs into the target tissue/target cells in vivo. For safety reasons, strategies based on vector delivery may be of only limited clinical use. The more desirable approach is to directly apply active siRNAs in vivo. Here, we report the effectiveness of in vivo siRNA delivery into skeletal muscles of normal or diseased mice through nanoparticle formation of chemically unmodified siRNAs with atelocollagen (ATCOL). ATCOL-mediated local application of siRNA targeting myostatin, a negative regulator of skeletal muscle growth, in mouse skeletal muscles or intravenously, caused a marked increase in the muscle mass within a few weeks after application. These results imply that ATCOL-mediated application of siRNAs is a powerful tool for future therapeutic use for diseases including muscular atrophy.

Deposition of tritiated water vapour to water surface in an outdoor field.

Deposition of tritiated water vapour in the atmosphere to a water surface was studied in an outdoor field, where elevated concentrations of tritiated water vapour existed in the atmosphere over twelve days. Exchange velocities of tritiated water vapour between air and water were evaluated from tritium concentrations in air and water obtained in the field experiment. It was found that the average of outdoor exchange velocities was about three times greater than that observed in a nuclear reactor room previously. Relationships between the outdoor exchange velocities and meteorological conditions were analysed to derive a multiple correlation equation. The wind speed was strongly correlated with the exchange velocity and the air temperature appeared to have an enhancing effect on the velocity. These observations were supported by a follow-up experiment conducted on a laboratory scale.

Health status of male preparatory school students lodging at a dormitory in Japan.

An investigation on the health status of 79 male preparatory school students lodging at a dormitory in Japan was carried out by questionnaire on lifestyles, subjective symptoms and mental status, as compared with two control groups: 73 medical students and 36 new employees. About 83 % of them slept less than 6 hours and 70 % of them did not exercise. Many students are troubled with back pain or lumbago(47%), sensation of incomplete bladder emptying(l6%), loss of visual acuity(55%) and eye fatigue(65%). Self-rating depression scale score of preparatory school students was not significantly higher than those of the control groups. The lifestyles of preparatory school students found to be very restricted and strained. However, no significant differences on mental adverse health effects was found among three groups.

[On susceptibility for carbon monoxide exposure. The effect of carbon monoxide exposure on hepatic drug metabolizing enzymes of mice].

Male mice were exposed to three levels of carbon monoxide, i.e. 500, 1,000 and 3,000 ppm for 60, 10 and 7 minutes per day respectively. Durations of the exposure were 1 and 5 days and 3, 6 and 9 weeks. As the effect of carbon monoxide exposure, induction of the drug metabolizing enzyme was observed, which was ascertained by the decrease of sleeping time by pentobarbital and by the increase of activities of liver microsomal p-nitroanisole demethylase and of aniline hydroxylase. These results should be due to an adaptive response to carbon monoxide exposure, but the mechanisms of the enzyme induction were not fully explained in this study. In 5 days' exposure to carbon monoxide, there was a dose-response relationship between the degree of carbon monoxide exposure and the extent of enzyme induction. But in the prolonged exposure to higher concentrations of carbon monoxide (1,000 and 3,000 ppm), the increase of drug metabolism became less pronounced and by 9 weeks' exposure to 1,000 ppm carbon monoxide, little induction of the drug metabolizing enzyme was observed. These results suggest that the induction of the drug metabolizing enzyme by carbon monoxide exposure has a certain limit.