Inbred carcinogen-resistant DRH rat strain developed form the closed colony Donryu rats on the basis of selective markers such as poor induction of γ-glutamyltranspeptidase and marked reduced incidences of liver tumors during 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) administration, which took more than 10 year. Previously, we observed that the Donryu rat liver was quite sensitive to both DNA-damaging and cytotoxic effects of 3'-Me-DAB, while the DRH rat liver showed tolerance to 3'-Me-DAB under the same conditions. In the present study, we examined mRNA levels related to the cytotoxic drug resistance mechanism in the livers of DRH and Donryu rats using RT-PCR. Contrary to our expectation, we observed rather similar levels of mRNAs between the two rat strains under the following conditions: i) mdr1 mRNA induction after 3'-Me-DAB administration. ii) MLP-2 mRNA reduction by 3'-Me-DAB administration, iii) MLP-2 mRNA induction after cholestasis and iv) constitutive levels of cMOAT gene expression. On the other hand, the levels of p53 mRNA and p53 protein in the Donryu rat liver were higher than those in DRH rat liver during 3'-Me-DAB administration, suggesting that the former were more sensitive to 3'-Me-DAB than DRH rat under these conditions. In conclusion, we failed to demonstrate the difference in the cytotoxic drug resistance mechanism between DRH and Donryu rats at least under the conditions examined in this study.

View full abstract

To elucidate the effects of a 10-week exercise training period on physical fitness and plasma catecholamine concentration at rest, and on natural killer cell activity in young healthy untrained females, subjects (20―22 years old. N＝16) carried out physical training by a protocol which consisted of treadmill jogging at a workintensity of 50% of their VO_2max two hours a day three times a week for ten weeks. VO_2max was increased significantly from 33.1±3.4 ml/kg/min to 38.3±6.6 ml/kg/min by the ten weeks of physical training (P＜0.005), and natural killer cell activity was also increased significantly from 31.9±14.3% to 46.4±18.4% (P＜0.05). The concentrations of epinephrine and norepinephrine before and after physical training were 18.3±8.7 pg/ml and 20.4±8.9 pg/ml, and 134.1±52.2 pg/ml and 248.1±106.8 pg/ml (P＜0.005), respectively. Changes in norepinephrine and epinephrine correlated with the change in VO_2max (r＝0.780, P＜0.005; r＝0.556, P＜0.05). While the change in natural killer cell activity correlated with the change in epinephrine (r＝0.623, P＜0.01), the correlation of the change in natural killer cell activity with change in norepinephrine did not reach statistical significance (r＝0.497, P＝0.0503). From these results we concluded that physical training augments plasma catecholamine levels natural killer cell activity at rest in young healthy females.

View full abstract

Depression is one of the most prevalent psychological health problems in occupational settings. Through literature review and the experience of previous investigations, it is now presumed that depression could mediate the association between workload and absence from work. In order to examine the above relationship, a follow-up investigation was conducted using male white-collar employees. The authors have been examining the association between work-related factors and employee health for some years, and vacation has become recognized as one of the important candidates for alleviating psychological problems in the workplace. In July 1996, the chance of leisure vacations within the past year and the presence of depression were examined by a self-administrated questionnaire. The subjects were followed-up for the rest on the year and absence from work was monitored. By analyzing 357 eligible subjects aged 20－59 years, the causal association between leisure vacation, depression, and absence form work was examined. Through correlation and log-linear analysis, the following findings were explored: The decrease of leisure vacation chances was correlated with the presence of depression, and depression contributed to an increase in the absence form work after adjustment was made for possible confounding factors. Leisure vacation could be independent of other work-related factors such as working hours, and it seemed to be significant to investigate positive effects of leisure vacation on psychological well-being in the workplace.

View full abstract

Rapid cycling affective disorder (RC) is defined as the presence of at least four affective episodes per years. We report two RC patients whose first manic episodes were considered to be induced by clomipramine. The first case, a 61-year-old female, suffered from RC after a manic episode with respect to oral administration of clomipramine. The second case, a 45-year-old female, showed cycle acceleration after a manic episode regarding intravenous drip infusion treatment with clomipramine. They had no manic or hypomanic episodes before the administration of clomipramine. We discuss the possible induction and worsening of RC through clomipramin-induced mania.

View full abstract

Parathyroid cysts are rarely located in the mediastinum. This report describes a 45-year-old man with a mediastinal parathyroid cyst. Video-assisted thoracic surgery was successfully performed to remove the cyst.

View full abstract

Dose rates in the sample chamber of a ¹³⁷Cs γ-ray irradiation apparatus (Nordion International Inc., Gammacell 40 Exactor) were accurately measured using an ionization chamber dosimeter. The dose rates obtained were 5.2m－7.2% higher at the upper and lower planes than at the middle plane in the sample chamber. In the process of starting and stopping irradiation, the additional dose during the movement of the source (end effects) was evaluated to be 0.85－1.21% (average 1.05±0.05%) of that estimated from the steady dose rate for 1min. When the irradiation period was less than 1 min, it was necessary to make a correction for the end effects in order to keep the error in irradiation dose below 1%.

View full abstract

Neurosurgical patients have been mainly treated by surgical procedures over the past decades. In addition, hyperbaric oxygen (HBO) therapy in neurosurgery has been used in patients with ischemic cerebrovascular diseases, head trauma, spinal damage, postoperative brain edema and others. However, the main therapeutic methods for neurosurgical diseases have changed dramatically due to developments in radiological techniques, such as radiosurgery and intravascular surgery. With changes in therapeutic methods, HBO therapy may become a very important treatment option for neurosurgical patients. For example, HBO therapy combined with radiotherapy (UOEH regimen) and anticoagulant therapy appear to be very effective in the treatments of malignant brain tumors and ischemic cerebrovascular diseases, respectively. On the other hand, medical examinations under hyper- and hypobaric environments have not yet been fully studied in the central nervous system compared to those in the cardiopulmonary systems. Moreover, the mechanisms of cerebral lesions in decompression sickness and acute mountain sickness remain unclear. Clinical neurologic approaches are very important in these fields. Hence, clinicians and researchers skilled in both neurosurgery and hyperberic medicine will be required for advanced treatment and preventive and industrial medicine.

View full abstract