In myelinated fibers of the sural nerves in Charcot-Marie-Tooth disease 1A (CMT 1A), with peripheral myelin protein (PMP) 22 gene duplication, it has been controversial whether axonal attenuation occurs or the myelin sheath thickens. Therefore, the relationship between the transverse axonal area and the number of myelin lamellae was morphometrically studied in myelinated fibers of the sural nerves in CMT 1A with PMP22 gene duplication to re-evaluate such relationships as are revealed in hereditary motor sensory neuropathy, type 1 without genetic diagnosis. In electron microscopic studies both the axonal circumference and natural log (1n) axonal area were significantly (P＜0.01) smaller in the CMT 1A group (n＝8) than in the control group (n＝9). Myelin lamellae numbers, however, were similar in both groups. In a regression analysis relating 1n axonal areas to the numbers of myelin lamellae, 1n axonal area in the CMT 1A group was significantly (P＜0.05) smaller than in the control group in myelinated fibers with the numbers of myelin lamellae equal to or over 40. Therefore, it was concluded that the axonal area was smaller in large-diameter myelinated fibers in the CMT 1A group than in the control group. We speculated on the existence of axonal attenuation due to the impaired effect of Schwann cells on myelinated axons in CMT 1A with PMP22 gene duplication.

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A comparative study on the possible involvement of several genes in the susceptibility of chemical carcinogenesis was carried out using carcinogen-resistant DRH rat and -sensitive Donryu and F344 rats. Previously, we observed that the induction of glutathione S-transferase placental form (GST-P) in the liver of Donryu rats by 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) was significantly greater than that of DRH rats. In the present study, we tentatively determined base sequences of the enhancer region including GPE-Ⅰ and GPE-Ⅱ (GST-P enhancersⅠ and Ⅱ) of GST-P genes of DRH, Donryu and F344 rats, but we did not observe any nucleotide polymorphism around these regions. Furthermore, the mRNA levels of silencer binding protein (NFA-1) for the GST-P promoter of rat liver were also similar in the DRH and Donryu rats. Since clonal expansion of putative preneoplastic GST-P-positive foci in the DRH rat liver was significantly suppressed during 3'-Me-DAB administration, we examined whether two opposite growth controling factors, TGF-α and TGF-β, may participate in such suppression of growth. It was supposed that mannose 6-phosphate / insulin-like growth factor 2 receptor (M6P / IGF2R), at least in part, activates TGF-β preproprotein. However, we observed that the levels of M6P / IGF2R mRNA in the livers of DRH were not higher than those of Donryu rats after being fed 3'-Me-DAB for 8 weeks. Another important factor in the carcinogenesis is insulin-like growth factorⅡ itself. Although liver tumors induced by 3'-Me-DAB in F344 had high levels of IGF-Ⅱ mRNA, little IGF-Ⅱ gene expression existed in normal adult livers of Donryu, F344 and DRH rats. High levels of IGF-Ⅱ mRNA were detected similarly in the livers of neonates from all these three strains of rats. Finally, we detected a significant increase of AFP (α-fetoprotein) mRNA in the livers of Donryu rats around 6 to 8 weeks from the start of 3'-Me-DAB feeding, which is in parallel with detrimental effects of this carcinogen on these rats. A reduced induction of AFP mRNA was observed in DRH rats under the same conditions. Further study will be needed to explain the lower tumor susceptibility in the DRH rat.

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Concentrations of ²³⁸U, ²³²Th and ⁴⁰K contained in the front glass of CRTs (cathode ray tube) of three television sets are measured by γ-ray spectrometry on the assumption of radioactive equilibrium in uranium and thorium series. The concentrations of ²³⁸U and ²³²Th are also measured by neutron activation analysis. The obtained results by the two different methods agree well within experimental uncertainty, showing that the radioactive equilibrium is found to be established in the present samples, and that the concentrations of ²³⁸U and ²³²Th in the glass can be measured by the γ-ray spectrometry as well as by the neutron activation analysis. We also found that although the obtained concentrations of ²³⁸U (6.5－13.5 ppm in weight) and ²³²Th (8.4－15.1 ppm) vary considerably between these three kinds of CRTs, those of ⁴⁰K (average:7.45±0.05 ppm) are almost equal for all samples. Moreover, the radiation dose rates are estimated for γ-rays from the CRT. At distances larger than 30 cm from the surface of the front glass, even the dose rate (5.65×10^-3 μSv / h) for the CRT containing the highest concentration of ²³⁸U and ²³²Th is smaller than one-tenth of that (7×10^-2 μSv / h) for background radiation, and that is practically negligible.

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During acute orthostatic stress, neurally mediated control of cardiac output (CO) and total peripheral vascular resistance (TPR) play an important role in the maintenance of systemic blood pressure. To examine the influence of thermal stress on the CO and TPR responses to orthostatic stress, 10 healthy male volunteers were exposed to normothermic control conditions followed by whole-body thermal stress produced by a cold or hot water-perfused suit during 5 min-70° head-up tilt (HUT) . HUT increased mean arterial pressure (MAP) by 3% of the pre-tilt value during normothermic control and cooling, whereas it decreased MAP by 4% of the pre-tilt value during heating. HUT decreased CO by 16－17% of the pre-tilt value under each thermal condition. The increase of TPR during HUT was exaggerated during cooling and inhibited during heating compared to normothermic control. Tilt-induced decrease of skin blood flow was greater during heating than cooling. These results suggest that the smaller increase of TPR rather than the CO change is responsible for the decreased MAP during acute orthostatic stress in hyperthermic humans. The contribution of skin vascular constriction to TPR changes during HUT is increased during heating and decreased during cooling.

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Mycobacteria are being isolated with increasing frequency from automated bronchoscope disinfection machines. This has led to misdiagnosis and nosocomial infections. In this study, we isolated Mycobacterium chelonae from a bronchoscope disinfection machine and found one strain to be resistant to 2% glutaraldehyde and sensitive to 70% ethanol. Since we began cleaning the sink of the machine with 70% ethanol, no mycobacteria has been seen throughout the machine.

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We report here 9 patients suffering from hydrofluoric acid burn who visited our clinic from July, 1979 to February, 2000. These 9 cases occupied 25% of all chemical burn cases experienced in our clinic. All the patients were men ranging in age from 20 to 53 (mean age 35 years; average 36.8 years). At the time of accidental exposures, 6 patients had been engaged in washing or cleaning work, and 2 had been changing the parts of instruments containing hydrofluoric acid. Eight patients received burns on the hands and / or fingers. During the work, 2 patients had used vinyl chloride or rubber gloves, but three patients employed no protection for the hands. After the symptoms began to develop, it was found that the glove of one patient had a pin hole. Coupled with the occasions described in previous reports, the causal factors of hydrofluoric acid burn could be divided as follows: 1) negligence or carelessness of workers, in particular skilled persons, in handling hydrofluoric acid, 2) ignorance of the dangerousness of hydrofluoric acid, 3) the presence of pin hole (s) in protection gloves, and 4) unexpected accident. Hydrofluoric acid is one of the most corrosive inorganic acids, and can produce progressive and serious tissue necrosis with severe pain. To prevent burns due to this chemical, enlightenment and reeducation of the workers regarding the hazard of hydrofluoric acid are necessary.

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A 36-year-old man, working in a chemical industry, had a generalized pruritic eruption. A forty-eight hour patch test revealed positivity for 1% hydroxylamine. Prevention of exposure to this chemical resulted in a dramatic improvement of the symptoms. Based on these findings, we diagnosed this case as occupational contact dermatitis due to hydroxylamine. There has been few case reports of contact dermatitis due to hydroxylamine. Histopathological examination revealed a marked spongiosis and a spongiotic bulla formation in the epidermis and follicular infundibulum, suggesting an allergic reaction.

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A 79-year-old Japanese man visited our clinic for evaluation of a large tumor on the left wrist and multiple keratotic tumors. He had handled creosote oil, which is a purified product of coal tar production, for 50 years. Physical examinations revealed poikiloderma with multiple hyperkeratotic tumors on the back of his hand and forearm bilaterally, and a cauliflower-like tumor, 80×60×15 mm in size, on the left wrist. Histopathologically, the large tumor showed a proliferation of atypical squamoid cells with many keratinization foci, indicating well-differentiated squamous cell carcinoma.

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Ferritin is the principal iron storage protein participating in iron metabolism. As serum ferritin levels often reflect the amount of storage iron in the body, physicians have measured serum ferritin in order to evaluate iron deficiency or overload. Although a rise in serum ferritin concentration occurs in iron overload, hyperferritinemia without it has been reported in some inflammatry diseases and malignancies. Some cytokines have been reported to be responsible for the elevation of ferritin production. Studies on serum isoferritin in adult Still's disease and other diseases, especially measurements of the proportion of glycosylated ferritin, have been widely accepted. Pathophysiological properties of the increased serum ferritin are not clear. However, we should be aware that the hyperferritinemia is not a result, but is profoundly participating in the disease process.

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