The main purpose of these experiments was the prevention of congenital malformations in offspring of alloxan-diabetic mice by insulin injections administered during pregnancy. The optimum dose of insulin and timing of its administration are described for mice made hyperglycemic by injection of alloxan of 80 mg. per kilogram of body weight. Copulated female mice were given alloxan intravenously on the fourth day of gestation, followed by 0.4 units of Lente insulin every twelve hours beginning thirty to thirty-six hours after alloxan injection, and continuing until the sixteenth day of gestation. The control group was given only the alloxan injection on the fourth day of gestation. Pregnant mice were sacrificed on the nineteenth day of gestation; fetuses were removed by laparotomy and examined for external defects and skeletal deformities. In fifty successful pregnancies treated with insulin, only one fetus (0.2 per cent) of 472 was malformed with a cleft palate; in fifty successful pregnancies given alloxan alone fourteen or 28 per cent of mice had one or more malformed fetuses. Altogether, twenty-two or 5.0 per cent of 437 fetuses in the latter group had malformations which included craniorhachischisis (seven fetuses), cleft palate (six fetuses), club foot (five fetuses), spina bifida, anencephalus, open eye, microphthalmia and skeletal deformities in one or more fetuses. The difference between the alloxan group and insulin treated group in the number of mothers having malformed fetuses, and in the number of malformed fetuses produced was statistically significant according to the chi-square test with a probability level of less than 0.01. In the alloxan group, increased body weight associated with advancing pregnancy was less advanced in mice having malformed fetuses than in those having normal fetuses. The foregoing tendency was also statistically significant with a probability level less than 0.01. However, no appreciable correlation was observed between the magnitude of hyperglycemia of mother mice and the frequency of fetuses with congenital malformations.

Children who began rinsing at 4 or 5 years of age benefited the most from the program. The program was inexpensive, simple to implement and well accepted by families and teachers. The conservative treatment policy in the public clinic likely contributed to the benefits derived by participants.

Abstract:The effect of fluoride ion

Cytotoxicity of sodium fluoride (NaF) on human diploid cells in exponential growth was investigated using a) Flow 1000 cells, passage No. 13, obtained from skin and muscle tissues of male black foetus, b) IMR-90 cells, passage No. 22, derived from lung tissue of female Caucasian foetus and c) primary fibroblast-like cell cultures from 5 Japanese whole foetuses. Diploid cells did not survive at 20 p.p.m. of ionic fluoride (F-) concentration. However, the cells were capable of proliferation with no significant impairment of growth up to 0.2 p.p.m. F-, a level which is much higher than the plasma concentration in human subjects from areas with highly fluoridated water. The growth of the cells was markedly affected by F- concentrations greater than 2 p.p.m.

No abstract

Community differences in caries prevalence in deciduous teeth were investigated. The Community Organization Data Base System (CODB) includes the data of 3-year-old children's dental examinations from 112 communities (cities, towns and villages) in Niigata prefecture in 1983, 1984 and 1985.This CODB also includes the data of 141 items concerned with community characteristics.

The structure-activity relationship of eclosion hormone from the silkworm, Bombyx mori, was analyzed. First, the probable active residues in silkworm eclosion hormone and also tobacco hornworm eclosion hormone were predicted by the average distance map method. To examine the contributions of those residues to the activity of silkworm eclosion hormone, Gly-substituted mutants for those predicted residues were produced by site-directed mutagenesis and their activities were evaluated by a bioassay. Finally, Glu12, Met24 and Phe25 were estimated to be the crucial residues for the eclosion hormone activity. The possibility of the development of a blocker of an eclosion hormone receptor on the basis of the present work is also discussed.

The purpose of this study was to evaluate the effects of a fluoride mouth-rinsing program (FMR) on dental health after the FMR program was completed. The state of dental health, including caries prevalence, was examined under blind recording conditions concerning participation in the FMR for 11th grade students in 10 public high schools, from 11 municipalities in Niigata Prefecture.The procedures of the FMR were carried out in these areas weekly, with 0.2% NaF, or daily, with 0.05% NaF, supervised by the classroom teachers in each school. The subjects, 321 in total, were classified into 3 rinse groups, each of which participated in the FMR for different periods of time, and a control group. The results of the statistical analysis showed increasing benefits in relation to increasing periods of participation. The reduction rate of caries prevention was the highest in the F11-group, subjects who participated in the program for 11 years from 4 to 14 years of age. The F11-group was 56.0% lower in the mean DMFT and 81.8% lower in the mean number of highly progressed carious teeth than the control group, with statistical significance in both cases. The percentage of students who had toothaches or who were absent from school in