Biomedical subjects
Publications and source records attributed to I Watanabe.
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Long-term investigations of polychlorinated hydrocarbon levels in mothers' milk were made from 1969 to 1976. The levels of p,p'-DDE, p,p'-DDT, dieldrin and PCB in mothers' milk were within the range reported by others. However, beta-BHC(Hexachlorocyclohexane) levels in the milk were 10 times that found in non-Japanese. A gradual decrease in the beta-BHC level in the milk was observed during this period. In contrast, the levels of p,p'-DDE, p,p'-DDT, dieldrin and PCB were consistent for the 7-year period. A significant correlation between the levels of PCB and p,p'-DDE in mothers' milk and blood was observed in the 1974-1976 samples. However, after prohibition of the use of chlorinated hydrocarbons, this relationship was less apparent in the 1972-1973 samples.
A survey of the daily PCB intake from the total diet of Japanese women was made for the years 1972 through 1976. All but one sample of 177 samples analyzed were contaminated with PCBs. Only one sample exceeded the acceptable daily intake (ADI) of PCBs of 5 micrograms/kg body weight in Japan. The average daily intake of PCBs per person was approximately 10 micrograms, which was very low compared to the ADI value. The main source of PCBs in the diet in Japan was inshore fishes, in contrast to fresh water fishes as in the U.S.A. The data obtained from this surveillance showed no statistically significant change of daily PCB intake from the diet during this 5-year period. However, there has been a marked decrease in the estimated intake of PCBs since 1972. Gas chromatograph analysis of the residual PCB patterns in the diet showed that the patterns in the marine products were somewhat different from those in dairy, meat, and poultry products. The former was similar to the pattern of the PCB standards mixture and the latter was similar to the PCB pattern found in human milk and tissue samples from the Japanese population.
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A single intracisternal injection of 0.4 ml of 1.25 and 2.5 percent gentamicin sulfate with preservative to healthy adult rabbits caused acute respiratory paralysis and severe seizure activity initially and paralysis of the limbs subsequently. In the white matter of the upper cervical spinal cord, multiple, minute, disseminated, spongy lesions were observed. They consisted of lysis of axis cylinders, edematous dilatation of myelin sheaths, and loss of astroglia and interfascicular oligodendroglia. Axonal end-bulbs formed at the periphery of the lesions. Clinically and morphologically, 0.025 and 0.25 percent gentamicin sulfate solution did not produce myelopathy. The spinal lesions were distributed differently from those of other chemical myelopathies in that they developed in the deeper white matter with sparing of marginal myelinated fibers. Circumscribed high concentrations and gentamicin, and vulnerability of myelinated axis cylinders and interfascicular oligondendroglia to gentamicin may be the main factors causing these lesions. When gentamicin sulfate without preservative was injected, neutrophil leukocyte infiltration occurred actively in the spongy lesions. In the cervical spinal ganglia some nerve cells underwent cytoplasmic vacuolation. In control animals a single intracisternal injection of saline or preservative did not result in the production of these lesions.
We isolated fairly stable lysogenic-like bacteria from a lysogenic state established between an amber mutant for the maturation protein gene of RNA phage Q beta (Q beta am 205) and its nonpermissive host BE110. These bacteria contained few mature phages intracellularly (less than 10(-3) plaque forming unit per cell), continued to grow with a potentiality to produce Q beta am 205 spontaneously, and showed an immunity-like response against homologous phage infection. These characteristics were maintained by growth in liquid medium containing anti-Q beta serum. We designated these cells as pseudolysogenic bacteria. The relative amounts of RNA genomes in these pseudolysogenic cells (about 10(2) infectious RNA strands per cell) indicated that the RNA genomes could replicate in nonpermissive cells and be distributed in daughter cells synchronizing well with cell division.
In order to demonstrate the stability and continuity of RNA coliphages (phages) in their natural habitats, we investigated the amount and group types of RNA phages in sewage samples collected continuously from domestic drainage in Japan proper and islands in the seas adjacent to Japan (abbreviated simply as islands, hereafter) over a 5-yr period from 1973 to 1977. It was found that the frequencies of isolation of RNA phages were fairly high and constant. The group types of RNA phages isolated were also stable in the three cities. Choshi, Niigata, and Toyama in Japan proper. The average for the three cities was group II:III = 3:1. The investigation in islands revealed that the frequencies of isolation of RNA phages were fairly high as in the case of the above three cities in Japan proper and the group types of RNA phages isolated were also stable. That is to say, group II phages were predominant on Rishiri Island, Rebun I., Iki I., and Tsushima I., which are located relatively near to mainland Japan, while group III phages were predominant on Amamiohshima I., mainland Okinawa, Ishigakijima I., and Iriomotejima I., which are located south of Kyushu. It can thus be said that the RNA phages in the domestic drainage of Japan proper and islands remained more or less stable over at least the 5-yr period, and an apparent difference in the geographical distribution of RNA phages in Japan exists between Kyushu and Amamiohshima I.
Acetylene reduction activity of intact rice plants was measured in closed assay chambers with plants grown in water culture. Acetylene was added to the liquid medium, and the ethylene formed was measured from both gas and liquid phases. After cutoff of mineral nitrogen supply and inoculation of fresh soil, rice plants grown from the seedling stage in water culture exhibited acetylene reduction activity after a lag period. However, rice plants grown in a paddy field and transferred to water culture were more suitable for N(2) fixation studies because of their higher, less variable acetylene reduction activity. The time course of acetylene reduction was monitored by continuous circulation of gas between the gas phase and the liquid phase, and the result showed an initial 2- or 3-h period of lower activity, followed by increased and almost constant activity up to 24 h. The effects on acetylene reduction activity of aeration, ammonium, chloramphenicol, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea addition are reported. Ammonium was inhibitive at 0.33 mM, and its depressive effect was alleviated by ammonium uptake by the plants.