Two types of mouse FM3A cell mutants deficient in 5-aminoimidazole-4-carboxamide ribonucleotide transformylase and their transformants isolated by human chromosome-mediated gene transfer

We isolated three adenine auxotrophic mutants (Adel, Ade2 and Ade3) of mouse FM3A cells deficient in 5-aminoimidazole-4-carboxamide ribotide transformylase (EC 2.1.2.3) activity. Adel and Ade3 but not Adel also lacked inosinicase (EC 3.5.4.10) activity. While Ade2 and Ade3 complemented each other, Adel complemented neither Ade2 nor Ade3, suggesting that two complementation groups exist in these mutants. We introduced human genes into the Ade2 and Ade3 cells by chromosome-mediated gene transfer. All the transformants tested were found to produce the human transformylase and inosinicase, and identical DNA bands containing human Alu sequences were detected in the transformants of Ade2 and Ade3. These mutants seem to have arisen by mutation in the same gene or adjacent genes, since only human chromosome 2 was capable of rescuing the genetic defects in all these mutants.     

Inhibitory activity of plant stilbene oligomers against DNA topoisomerase II

The inhibitory activity of 40 stilbene oligomers isolated from six plant species against topoisomerase II was evaluated, of which nine compounds showed a potent inhibitory effect, stronger than daunorubicin, a topoisomerase II inhibitor, used as an anti-cancer drug. The specificity of active stilbene oligomers on topoisomerase II was assessed by their effect on DNA restriction enzyme. In particular, specific inhibitory activity was observed in alpha-viniferin 13-O-beta-glucopryranoside (2) and hemsleyanol C (13).     

Changes of the activities of superoxide dismutase after exposure to the fume of heavy metals and the significance of zinc in the tissue

Pathological changes induced by cadmium aerosol had features common to the changes evoked by oxidants. Female rats were exposed to fumes of lead, antimony, zinc and cadmium (15–100 nmoles/m³). One hour after termination of exposure, superoxide dismutase (SOD) activity in erythrocytes of the exposed rats lowered by 15–40%. SOD activity of lung lavage fluid also lowered by 20–35% at the 2nd day after the exposure. The inverse value of SOD activity (l/SOD) in erythrocytes and of lung lavage fluid were proportional to the molar exposure level adjusted by the particle size (Dixon plot), irrespective of the difference of the exposed substance. The ratio of dry weight to wet weight of the lung was 4.3–26% lower than the control value on the later period after the exposure. With the heavy metal exposure, the uptake of the exposed metal was found to be proportional to the endogenous zinc concentration, which was correlated well with the change of SOD in the lung and in erythrocytes. Cadmium decreased the zinc concentration after the exposure.     

Evaluation of a community-based health education program for salt reduction through media campaigns

PURPOSE: To provide the strategies, achievement and evaluation of a community health education program for salt reduction with media campaigns. METHODS: The intervention community was Kyowa town (A district of Chikusei city, census population in 1985 = 16,792) where we have systematically conducted a community-based blood pressure control program since 1981, and health education on reduction of salt intake since 1983 for primary prevention of hypertension. The education program was performed through media campaigns including use of banners, signboards, posters, and calendars with health catchphrases. We also used catchphrase-labeled envelopes when sending documents from the municipal health center to individuals. Health festivals were held annually to enhance health consciousnesses and to improve health behavior. Some of the posters and calligraphy were painted or drawn by elementary schoolchildren as part of their education. The program was evaluated by repeated questionnaires and examination of salt concentrations of miso soup and dietary salt intake. RESULTS: Between 1983 and 1988, the prevalence of persons who were aware that health consultation including blood pressure measurements were available at the town office increased from 65% to 84%. The prevalence of those who knew the salt intake goal (10 g or less/day) increased from 47% to 63% and that of those who reported to reduce salt intake also increased from 38% to 58%. As for salt concentrations of miso soup, the proportion with less than 1.1% increased from 47% to 66% between 1985 and 2004. Age-adjusted mean salt intake for persons aged 40-69 years declined from 14 g to 11 g in men and from 12 g to 10 g in women between 1982-1986 and 2000-2004. CONCLUSION: A long-term systemic education program through media campaigns proved feasible with the cooperation of community leaders, schools and food associations.     

Human leukocyte antigens in Japanese patients with biliary atresia: retrospective analysis of patients who underwent living donor liver transplantation

Biliary atresia (BA) is a neonatal obstructive cholangiopathy characterized by a fibrosclerosing obliteration of the extrahepatic bile duct. The aim of this study was to investigate the relationship between human leukocyte antigens (HLA) and susceptibility to BA. We retrospectively analyzed 392 Japanese patients with BA and without extrahepatic anomalies who underwent living donor liver transplantations at our institute. Healthy Japanese volunteers (n = 828) served as normal controls. A significant positive association was observed between BA and HLA-DR2 (39.0% of patients vs. 30.4% of controls, odds ratio = 1.46, p = 0.029). Two-locus analyses disclosed that DR2 was not independently associated with BA, but the increased frequency of HLA-A24 and -B52 reflected the linkage disequilibrium between -A24, -B52, and -DR2. Moreover, the frequency of the haplotype HLA-A24-B52-DR2 was significantly higher in patients with BA than in the general Japanese populations described in the literature (odds ratio = 2.20, p = 0.00124). These results indicate that the gene for BA susceptibility is in close linkage disequilibrium with the HLA-A24-B52-DR2 haplotype observed in the Japanese population. We speculate that a gene at the locus close to HLA plays an important role in the pathogenesis of BA.     

Role of O6-alkylguanine-DNA alkyltransferase in the cytotoxic activity of cloretazine

Cloretazine (VNP40101M; 101M; 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl]hydrazine) is a sulfonylhydrazine prodrug that generates both chloroethylating and carbamoylating species on activation. To explore the molecular mechanisms underlying the broad anticancer activity observed in preclinical studies, cloretazine and chloroethylating-only [i.e., 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine] and carbamoylating-only (i.e., 1,2-bis(methylsulfonyl)-1-[(methylamino)carbonyl]hydrazine) analogues were evaluated in five murine hematopoietic cell lines. These cell lines were separable into two groups by virtue of their sensitivity to 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine; the sensitive group included L1210, P388, and F-MEL leukemias (IC50s, 6-8 micromol/L) and the resistant group consisted of Ba/F3 bone marrow and WEHI-3B leukemia cells (IC50s, 50-70 micromol/L). Resistant cells expressed O6-alkylguanine-DNA alkyltransferase (AGT), whereas sensitive cells did not. A correlation existed between AGT expression and the functional status of p53; AGT- cells possessed defective p53, whereas AGT+ cells contained wild-type p53. Based on recent findings on regulation of AGT gene expression by others, we suspect that silencing of the AGT gene by promoter hypermethylation frequently occurs during tumor progression involving p53 inactivation. O6-Chloroethylguanine is the initial DNA lesion that progresses to lethal interstrand DNA cross-links. Cloretazine exhibited a much higher preference toward the O6-chloroethylation of guanine, as measured by the difference in IC50s to wild-type and AGT-transfected L1210 cells, than 1,3-bis(2-chloroethyl)-1-nitrosourea, which targets the same site in DNA. Preferential toxicity of cloretazine against AGT- tumor cells coupled with decreased toxicity to AGT+ cells in host tissues constitute the therapeutic basis for cloretazine.