Akihiko Kaetsu

Possible role of 1-methylnicotinamide in the pathogenesis of Parkinson's disease.

This study tested the hypothesis, that nicotinamide N-methyltransferase (NAMT) activity in the brain could convert nicotinamide to 1-methylnicotinamide (MNA) and by that means damage the nigro-neostriatal dopaminergic neurons. The NAMT activities of rat brain and liver were assayed with gas chromatographic-mass spectrometric analysis in a selected ion monitoring system. They amounted to 0.30 nmol/mg x h and 0.51 nmol/mg x h, respectively. The MNA injection in rat substantia nigra pars compacta significantly decreased dopamine content in the striatum. NADH oxidation and lipid peroxidation by MNA via rat brain submitochondrial particles (SMP) under the condition of pH ranging from pH 6.0 to 10.0 were verified. The pH optimum for the NADH oxidation was 9.0. The pH optimum for the peroxidation of the lipid composing SMP by MNA was also 9.0. The lipid peroxidation in this assay was suppressed by superoxide dismutase. The superoxide anion formed by MNA via mitochondria might be involved in the etiology of Parkinsons disease.

An outbreak of measles in Saitama City in 2007. What is the vaccination strategy to eliminate measles in Japan

In the present study, to elucidate an outbreak of measles in Saitama City, Japan, we analyzed the data for all notified subjects with measles. According to an active surveillance program, a total of 464 subjects were notified in 2007. The clinical criteria for the diagnosis of measles were defined as at least 3 days of a generalized maculopapular rash; a fever of 38.0°C or more; and cough, mucus, or pharyngitis. Two peaks according to age group were recognized: namely, children less than 2 years of age and adolescents from 15 to 19 years of age. The latter peak was associated with the period of time when the measles-mumps-rubella vaccine had become a social problem (40.9% of vaccinees and 41.6% of non-vaccinees in this group). Japan is said to be a developing country regarding its measles vaccination strategy. In addition, no national program against measles has yet been established. Continuous efforts to increase immunization coverage are needed to interrupt indigenous measles transmission. The Japanese Ministry of Health, Labor and Welfare should therefore plan and implement a nationwide program to eliminate measles in Japan.

[Genomic analysis of enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains isolated in Saitama City].

To elucidate the origin of infection, we conducted epidemiological and bacteriological studies to clarify the origin of five sporadic outbreaks of enterohemorrhagic Escherichia coli (EHEC) O157:H7 between May and July 2007 in Saitama City and its outskirts. Of the 20 subjects were reported; including 6 patients and 5 infected persons, none of the 9 symptomatic subjects developed hemolytic-uremic syndrome. No association was confirmed between infection and food materials, but 11 organisms showed almost the same chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis. Our results suggested that these 5 sporadic outbreaks were part of a diffuse outbreak induced by an EHEC O157:H7 strain having a single origin.

Serum leptin levels and their association with several factors related to arteriosclerosis among medical students in Japan.

The association between serum leptin levels and several factors related to arteriosclerosis were studied in subjects who were Japanese medical students taking no medications. The group was comprised of 75 males and 35 females. The age distribution in males was 21.4 to 29.8 years (median age, 24.0 years) and in females was 21.3 to 29.9 years (median age, 22.9 years). Statistical analyses were performed using the Wilcoxon rank sum test and Spearman correlation. Median levels of serum leptin were 3.3 ng/ml in males and 7.6 ng/ml in females. The largest correlation observed was widi percent body fat irrespective of sex [males; r=0.775, p<0.001, females; r=0.553, p<0.001]. However, body mass index (BMI) was similarly well correlated with serum leptin [r=0.631, p<0.001] in males but not in females [r=0.305, p=0.075]. A negative correlation was observed between high density lipoprotein cholesterol (HDL-C) and leptin in both sexes [males; r=-0.298, p<0.01, females; r=-0.363, p<0.05] .respectively. Percent body fat, BMI, diastolic blood pressure, apolipoprotein B, and HDL-C were the most significant factors in males. Percentage of body fat and HDL-C were the most important factors in females.