Ontogeny of turbiditaxis in hatchery-reared Japanese anchovy Engraulis japonicus.

The ontogenetic change in turbiditaxis (i.e. attraction to turbid waters) was examined in the larvae and juveniles of Japanese anchovy Engraulis japonicus by testing three levels of turbidity (0, 20 and 100 ppm of kaolin). Larvae of 12, 20 and 30 mm standard length (LS ) exhibited turbiditaxis to both 20 and 100 ppm of kaolin, whereas 6 mm LS larvae and 45 mm LS juveniles did not exhibit any turbiditaxis. Turbiditaxis might explain the ontogenetic habitat shift from coastal to offshore waters reported for this species.

Ontogeny of antipredator performance in hatchery-reared Japanese anchovy Engraulis japonicus larvae exposed to visual or tactile predators in relation to turbidity.

Laboratory experiments revealed distinct effects of turbidity on the survival of Japanese anchovy Engraulis japonicus larvae when exposed to either visual (jack mackerel Trachurus japonicus) or tactile (moon jellyfish Aurelia aurita) predators. The experiments were conducted in 30 l tanks with three levels of turbidity obtained by dissolving 0, 50 or 300 mg l(-1) of kaolin. Predators were introduced to experimental tanks followed by larvae of E. japonicus ranging from 5 to 25 mm standard lengths (L(s) ). When exposed to T. japonicus, the mean survival rate of larvae was significantly higher in 300 mg l(-1) treatments compared to the other turbidity levels. When exposed to A. aurita, however, there was no difference in the survival rates among different turbidity treatments. The survival rates when exposed to either predator improved with larval growth. The logistic survivorship models for E. japonicus larvae when exposed to A. aurita had an inflection point at c. 12 mm L(s) , suggesting that their size refuge from A. aurita is close to this value. Comparison to a previous study suggests a high vulnerability of shirasu (long and transparent) fish larvae to jellyfish predation under turbidity. This study indicates that anthropogenic increases of turbidity in coastal waters may increase the relative effect of jellyfish predation on fish larvae.

Intraosseous pneumatocyst of the scapula.

Intraosseous pneumatocyst is a gas-containing cyst-like lesion that occurs most frequently in the ilium, sacrum or vertebrae. We present a case involving the left scapula that was found incidentally on CT. To our knowledge, intraosseous pneumatocyst of the scapula has not been previously reported.

Effect of a static magnetic field on ion transport in a cellulose membrane.

A cellulose membrane was exposed to the static magnetic field (SMF) in the presence of KCl solution and ion transport through the membrane was measured before and after the SMF exposure. SMF at 0.24 T significantly enhanced the rate of ion transport, especially after the first exposure (p<0.05), while the increased ion transport rate did not return to the initial basal level after exchange of the aqueous medium. These results suggest that an irreversible, temporal conformation change took place on the cellulose membrane or on the water bound to the cellulose surface. The accelerating effect of SMF on the ion transport seems to have occurred as a result of stabilized hydration layer on the cellulose surface.

Static magnetic field effects on bone formation of rats with an ischemic bone model.

Effects of a static magnetic field were studied on bone formation using an ischemic rat femur model. Metal rods were prepared from magnetized and unmagnetized samariun cobalt to have tapered structure, both with the same geometrical dimension, and were implanted transcortically into the middle diaphysis of 88 rat femurs. Both sides of the rat femoral artery were ligated to create an ischemic bone model, followed by implantation of the tapered rod to the femur. The bone mineral density (BMD) and weight of the femurs were measured at 1st and 3rd week after implantation. The result at the 3rd week post-implantation revealed that the BMD and weight of the ischemic bone model rats were significantly reduced, compared with that of non-operated femur. It was also found that the magnetized group had significantly higher bone weights than the unmagnetized (p<0.05). The BMD of the rats implanted with the magnetized rods were similar to those of the non-operated (p>0.05). This enhancement of the femoral bone formation of the ischemic rat model by the static magnetic field seems to be due to the improved blood circulation of the femur.

Seroepidemiology of human group C rotavirus in Japan based on a blocking enzyme-linked immunosorbent assay.

A novel blocking enzyme-linked immunosorbent assay (BL-ELISA) was developed for detection of antibodies to human group C rotavirus (CHRV). The specificity of the BL-ELISA was confirmed by using animal sera hyperimmunized to group A and group C rotaviruses and paired sera from five patients with acute CHRV gastroenteritis. Furthermore, there was concordance between the BL-ELISA and a neutralization assay for CHRV in 226 (95%) of 238 samples. By using the BL-ELISA, we determined the seroprevalence of CHRV in 704 serum samples obtained from nine different age groups of inhabitants of Okayama Prefecture, Japan, in 1992, 1994, and 1996. As a result, 211 sera (30%) were found to be positive for CHRV antibodies. The seroprevalence gradually increased with age and reached 52.7% in the oldest individuals. A further analysis of the youngest age group suggested that CHRVs predominantly prevail in persons older than 3 years of age in Japan. When comparing the three sampling years, a larger percentage of antibody-positive sera was detected in 1994 than in either 1992 or 1996 in individuals between 6 and 15 years of age, reflecting the occurrence of a CHRV outbreak among children during the winter of 1992 to 1993 that was previously documented. These results indicate that CHRV infections may occur more frequently in spite of the relatively low detection rate of the virus.

Detection of HeLa cell contamination--presence of human papillomavirus 18 DNA as HeLa marker in JTC-3, OG and OE cell lines.

There are warnings of the contamination of cell cultures with HeLa cells in many laboratories in the world. The cell lines JTC-3, OG and OE that were established in Okayama in 1959, 1969 and 1971, respectively, were examined for human papillomavirus (HPV) 18 DNA by Southern blot hybridization. The HPV 18 DNA detected in these three cell lines showed hybridization patterns characteristic of the HPV 18 DNA in the HeLa cell line established in 1951. Southern hybridization patterns of HPV 18 DNA in the cellular DNA of the C4-II cervical cancer cell line that was established in the USA in 1962 was different from that of HeLa cells. These results suggest that the JTC-3, OG and OE cell lines have been contaminated by HeLa cells.