The auto-regulation mechanism of liver regeneration after partial hepatectomy was investigated in rats. Hepatocytes isolated from the individual remnant livers at various times after 70% removal of the liver were cultured, and determination of DNA synthesis of the cultured hepatocytes and collection of culture supernatants were performed. The maximum value of DNA synthesis was observed at 1 day after the operation and then gradually decreased, and the liver weights recovered rapidly during 2－4 days. The culture supernatants harvested from these primary cultured hepatocytes isolated from the rats at 2, 3 and 4 days after the operation suppressed dose-dependently DNA synthesis of hepatocytes which were isolated from normal rats and stimulated by epidermal growth factor (EGF) and insulin in vitro. The supernatants were non-cytotoxic against hepatocytes, and the activity of them was fairly stable for acid and heat treatments but not for proteolytic enzyme. No inhibition of the binding of EGF to the receptors on hepatocytes was observed. Furthermore, the factor showed an inhibitory activity of mitogen-induced DNA synthesis of human peripheral blood lymphocytes in culture. These results suggested that hepatocytes themselves might modulate the process of liver regeneration by secreting a growth inhibitory factor.

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Microvascular features of normal rat livers and bile duct system were examined with the vascular casts using methacrylated resin. Portal vein branches not only showed regular tapered down bifurcations but also had many side branches, some of which were directly connected with sinusoids. Terminations of hepatic arterial branches were divided into three types: 1) Many branches pouring into peribiliary capillary plexus (PBP), 2) branches dierectly pouring into periportal sinusoids and/or peripheral portal vein branches via arterio-portal anastomoses, and 3) anastomoses with periportal vascular plexus. PBP was composed of rich vascular networks. In large portal tracts, the plexus showed two layers, that is, the inner layer made up of a close network of capillary vessels and the outer layer consisting of a loose network of arteries and veins, while the PBP in the small portal tracts was composed of only a single layer of loose capillary network. Transitional features of these two patterns were found in the medium-sized portal tracts. PBP was supplied by afferent vessels from the interlobular hepatic artery as described above, and were directly connected with interlobular branches of the portal vein (internal root). The extrahepatic bile duct revealed a much richer vasculature than the intrahepatic bile duct. Both arterial and venous branches were ramified at almost right angle from a pair of arteries and veins running parallel with the bile duct. Occasional strictures, which might have been sphincter portions of the media, were noted at the branching sites of the artery. The orfice of the common bile duct at the Vater's ampulla was a small hole-like structure surrounded by a single circular layer of capillary network. Since branchings and anastomoses of the hepatic artery as well as the portal vein were much more complicated than those previously reported, we described several discrepancies between literatures.

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In this paper, we present formulae for the number of |Y(V)^Fsg | (g∈GL(V)^F, F: Frobenius) with respect to the Green polynomials of GL_n in the Deligne-Lusztig theory.

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A simple passive tobacco smoke exposure system was developed for laboratory animals. The system consisted of a tobacco smoke generator and an exposure chamber. Performance testing was conducted using Fischer 344 rats. The rats were exposed to passive tobacco smoke generated by 20 cigarettes per day for 3 months. The concentration of the cigarette smoke aerosol (particle phase) in the chamber can be kept almost constant during exposure. The daily average mass concentration was 10.0±4.3 mg/m³ and the carbon monoxide was 79±22 ppm during exposure.

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Experiments were made in which Aedes aegypti mosquitoes fed on a dog infected with Dirofilaria immitis, in order to determine the distribution pattern of microfilariae (Mf) in the dog's periphery blood and the number of Mf taken by the mosquitoes. Mosquitoes fed on an anesthetized dog at some 50 shaved skin spots and they were weighed immediately before and after feeding. This enabled us to examine not only the Mf number taken by each mosquito but also the Mf intake density in terms of Mf number per mg of blood. The Mf intake density showed a wide variation at the different parts of the dog's body, and the frequencies of Mf showed un-even distributions which were fitted best by the negative binomial Significant differences were detected in the Mf intake density at different parts of the skin, but these differences were concluded as a non-consistent result because a similar result was not reproduced in the next experiment. It was presumed that not only the Mf number per mosquito but also the Mf intake density increased as the blood intake by the mosquitoes increased. This increase of both the Mf number per mosquito and the Mf intake density was also supported by another experiment in which mosquitoes were fed at the same skin spots consecutively one after another.

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The relationship between low birth weight infants (LBW) and 3 perinatal factors; pre-pregnant maternal Body Mass Index (BMI; Quetelet's index), maternal height and parity was investigated by the log-linear analysis, using the birth records of an obstetric facility at Naha city. In this facility there were 4,894 deliveries from Jan. 1978 to Dec. 1987. Of the 4,894 infants, 4,142 were live singletons with available data for the analysis. The odds ratio of each risk factor was calculated by the log-linear model. Women with lower pre-pregnant BMI (<20) had an increased LBW risk by 1.80 (95% CI: 1.32－2.43) compared to women with higher pre-pregnant BMI (20<) Lower maternal height (150 cm >) was associated with significant LBW risk (1.47; 95% CI: 1.03－2.12). Primiparae had higher LBW risk than multiparae (1.68; 95% CI: 1.25－2.28). In this analysis we evaluated the interaction effects on LBW occurrence of the three factors and found no interaction effects among them.

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Male and female Wistar rats were exposed to ethylene oxide (EO) at a concentration of 250 ppm. 6 hours a day, 5 days a week for 17 weeks simultaneously, and the sexual difference in susceptibility of the peripheral nerve to EO was investigated. Both male and female rats of the exposed group showed paresis of the hindlegs, but sexual difference did not affect the degree of this abnormality. In histopathological examinations, axonal degeneration of the myelinated fibers in the peroneal nerve, the nerve to the soleus muscle and in the gracile fascicles of the spinal cord was revealed. The nerve to the soleus muscle degenerated more severely than the peroneal nerve. Sexual difference played no part in the severity of the degenerations in each nerve or in the gracile fascicles. From these observations, we concluded that there was no significant difference in the susceptibility of the peripheral nerve to EO between male and female rats.

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(Na, K) ATPase is composed of two heterologus subunits; a catalytic α subunit and a glycosy lated β subunit whose role remains unclear. To elucidate a possible role of the β subunit, the α and β subunits of Torpedo californica (Na, K) ATPase were expressed in the Xenopus oocytes system which allows the specific programmed synthesis of different subunits in a cell by alternately injecting individual mRNA. When oocytes were injected with mRNA α alone, no significant increase in (Na, K) ATPase activity was observed, whereas a slight increase was detected in oocytes injected with mRNA β alone. The pre-existing β subunit, which had been synthesized by injecting mRNA β, could assemble with the α subunit, expressed later in the single oocytes and the resulting α β acquired both ouabain-binding and (Na, K) ATPase activities. The results reported in this paper strongly indicate that the β subunit plays an essential role, at least in the biogenesis of the enzyme.

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To estimate a reasonable and convenient method for the assessment of daily energy expenditure in workers, the validity of a calorie counter combined with an accelerometer (Kenz Calorie Counter) was tested during treadmill exercise. Ten male and female students each volunteered for exercise on a treadmill at different running speeds: 9 speeds at 2 to 10 km/h each for male subjects; 8 speeds at 2 to 9 km/h each for female subjects. Energy expenditure measured with respiratory gas analysis was compared with that estimated by the calorie counter outfitted on the waist of the subjects. For running speed slower than 9 km/h, the work intensity reading on the calorie counter increased in direct proportion to the speed of the treadmill. The correlation between running speed and the work intensity reading of the calorie counter was linear up to 8 km/h (y=0.95 x-0.2, r=0.96, P<0.001). A linear relationship during tread-mill exercise (at a speed of less than 9 km/h) was also established between energy consumption measured by respiratory gas analysis and that estimated from the calorie counter (y=1.00 x+11.7, r=0.94, P<0.001). Thus, we validated the usefulness of the calorie counter for the assessment of energy expenditure during daily physical activities.

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This paper addresses an epidemiologic approach to the quantitative evaluation of screening programs for chronic diseases. A new formula is advanced for the quantitative relationship between the yield of a screening program and the natural history of chronic disease, based on the two stage model of disease progression. The formula was applied to follow-up data of the participants and the proportions of cases detected by the screening were estimated as 15.3% for all diseases and 43.8% for hypertensive disorders. The formula is useful for continuous monitoring of ongoing screening programs as well as for potential impact evaluation of hypothetical programs.

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This is an autopsy report of multiple primary cancers observed in a patient who had clinically been diagnosed as chronic arsenic poisoning. An 88-year-old man, non-smoker, had worked in an arsenic mine for 6 years from the age of 47. He had undergone operations for Bowen's disease and gastric cancer at ages 80 and 86, respectively. At autopsy, squamous cell carcinoma of the lung and a polypoid lesion in the piriform recess were found. Furthermore, microscopic examination revealed latent prostatic adenocarcinoma and oncocytoma in the kidney. The polypoid lesion of the piriform recess appeared to originate from the duct of the minor salivary gland in the pharynx, showing an adenoid cystic carcinoma-like pattern with squamous cell carcinoma in part. The cause of death was thought to be respiratory failure due to bronchopneumonia and pulmonary edema as well as hydrothorax, and chronic heart failure following ischemic heart disease. Bowen's disease was followed by four internal malignant tumors, even though the etiological relation between these cancers and arsenic is not clear.

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A case of delayed Sumithion^® (fenitrothion) intoxication is reported. A 52-year-old man ingested 10 ml of Sumithion^® in order to commit suicide with alcohol and triazoram. Several hours later, he was admitted to our hospital because of clouding consciousness. On admission, he was somnolent, but had no other symptoms, especially suggested organophosphorus intoxication. After 40 hours, fasciculation and salivation, which are early symptoms of organophosphorus intoxication, gradually appeared. The concentration of Sumithion^® in the blood was measured during the course and its metabolism was represented phalmacokineticaly by a 2-compartment model. The retarded metabolism of the Sumithion^® was suggested by this model. It is considered that the retarded metabolism of Sumithion^® caused the delayed intoxication.

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