Radiosensitivity of mouse skin epithelial cell line established in serum-free culture: an alternative to animal use.

A cultured line of murine skin epithelial cells was established to investigate the potential use of cultured cells as an alternative to animal use in radiation research. C3Hf/Sed newborn mouse skin cells have been successfully cultured in serum- and Ca(2+)-free medium with no terminal differentiation to keratinized cells. Presently, more than 25 passages have passed with no loss of stem cell capability. The radiosensitivity and repair of sublethal and potentially lethal radiation damages were investigated in this epithelial cell line. The population cell doubling time was 25 +/- 2.9 hr at 37 degrees C. The clonal growth of epithelial cells after irradiation was performed in the serum-free medium in the presence of lethally irradiated skin fibroblasts. Single dose survival curves of exponentially growing epithelial cells were investigated from the seventh to the twenty-third passages, and no significant changes in radiosensitivity and doubling time were found. The confluent epithelial cells also showed an identical sensitivity to radiation. The alpha/beta ratios of survival curves fitted by the linear quadratic model were 6.1 +/- 1.0 and 5.9 +/- 1.3 Gy for cells in exponential and confluent phases, respectively. The survival curve of epithelial cells left in confluence for 8 hr after irradiation showed a smaller beta value than that of cells plated immediately after irradiation with a resultant alpha/beta ratio of 9.5 +/- 3.8 Gy. This alpha/beta ratio was identical to those found in many animal experiments, suggesting a potential use of this cell line as an alternative to animal use. The magnitude of repair of sublethal damage following 6 Gy was greater than that following 3.9 Gy. Survival curves were also obtained following twice-a-day irradiations with no sign of rapid repopulation. These results are discussed by comparing with published in vivo and in vitro data.     

Primary care considerations--17-ketosteroid sulfate-17-hydroxycorticosteroid method as a clinical stress indicator]

In primary care, the management of stress-related diseases occupies a wide spectrum of prevention and treatment, from holistic health care to final cure, centered on medical health and an organic integration of body, mind, and social parameters. Inquiries are being made at examinations and interviews to obtain information on the health condition of the patient, but, they are inadequate. There is a need for an objective indicator to help in the diagnosis. With the introduction of the Stress Barometer (measurements of 17-ketosteroid sulfates and 17-hydroxy-corticosteroids) it has become possible to obtain critical information on a patient in a very short time. This method allows early detection of stress, depression state and tiredness from work which is not presently possible from blood tests. It then becomes possible to call the patient's attention to these matters and to work at increasing awareness, energy levels, and responses to the conditions that are determined in this manner.     

Clinical evaluation of rapid diagnostic kit detecting separately influenza A and B viruses

The Directigen Flu A + B kit, a rapid diagnostic device for influenza virus A and B was evaluated. The nasopharyngeal aspirates were obtained from 239 patients who visited our hospital, between January and March, 2000, presenting flu-like symptoms. Influenza virus AH1: 77 and AH3: 51 were isolated from 128 specimens and none from 111 specimens. Directigen Flu A + B showed 115 specimens positive and 106 specimens negative. The sensitivity and specificity of this kit were 89.8% (115/128) and 95.5% (106/111) compared with viral isolation. Agreement on positive and negative interpretations between Direction Flu A and this kit was 97.9% (234/239). In the evaluation of this kit for influenza B virus, 60 frozen nasopharyngeal aspirates collected from February to April, 1999 were used. The sensitivity and specificity of this kit were 88.9% (16/18) and 88.1% (37/42) compared with viral isolation. Agreement on positive and negative interpretations between FLU OIA and this kit was 91.7% (55/60). The Directigen A + B demonstrated sensitivity and specificity equivalent to the conventional kits in nasopharingeal aspirates. This kit can also differentiate influenza A and B viruses, a feature which is useful for treatment using anti-viral agents such as amantadine and neuraminidase inhibitor. To date, the kit is the most effective tool for the rapid diagnosis of influenza.     

Alcohol-Metabolizing Enzyme Polymorphisms and Alcoholism in Japan

The liver enzymes, alcohol dehydrogenase (ADH) and aldehyde de-hydrogenase (ALDH), which are responsible for the oxidative metabolism of ethanol, are polymorphic in humans. Cytochrome P450IIE1 , an ethanol-inducible isozyme of liver microsomal P450 , is also important in ethanol metabolism. Genetic polymorphisms in the 5'-flanking region of the human cytochrome P450IIE1 gene have recently been reported. We hypothesized that the polymorphisms of ADH , ALDH , and P450IIE1 modify the susceptibility to development of alcoholism. We determined the genotypes of the ADH2 , ALDH2 , and P450IIE1 loci of 96 Japanese alcoholics and 60 healthy male subjects, using leukocyte DNA by the restriction fragment-length polymorphism by polymerase chain reaction. The alcoholics had significantly higher frequencies of the ADH2 ¹ and ALDH2 ¹ alleles than did the healthy subjects. No significant difference in the frequency of the P45011E1 genotype was observed between the alcoholics and the healthy subjects. In conclusion, genetic polymorphisms of the ADH and ALDH genes, but not of the P45011E1 gene, influence the risk of developing alcoholism in Japanese.