Two consecutive generations of mice were raised at graded room temperatures ranging from 12 to 32°C at intervals of 2°C. The delivery rate decreased at 30 and 32°C, and the litter size and weaning rate decreased above 28°C. No significant difference was demonstrated within the 12-26°C range for any reproduction parameters observed. The body weights of the first-generation mice born at 22°C and transferred to rooms at assigned temperature did not significantly differ within the 14-28°C range after 8 and 16 weeks of exposure. The second-generation mice born and reared at various temperature levels did not show significant inter-group difference in weight within the 20-26°C range at any age in the growth period. No significant inter-group difference was observed within the 20-26°C range in respect of food and water intakes in the second-generation mice. Hematological values and organ weights in the first and second generation mice of both sexes did not significantly differ in any parameter within the 20-26°C range. The results suggest the temperature range of 20-26°C to be optimal for laboratory mouse rooms.

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The effects of thyrotropin releasing hormone tartrate (TRH-T) on the behavior of cytosine arabinoside (Ara-C) induced ataxic mice were studied. The ataxic mice were prepared by injecting 50 mg/kg/day subcutaneously on the 2nd, 3 nd and 4 th postnatal days. Spontaneous motor activities were measured with a movement spectrum analyzer (ANIMEX-2) and the degree of ataxic gait determined by an open-field study. Cerebella from these animals were subjected to histopathologic examination at 4, 8 and 12 weeks of age. Ataxic gait became improved moderately and spontaneous motor activities increased slightly following administration of TRH-T. The effects of TRH-T on ataxia and spontaneous motility in the Ara-C injected mice varied with the age, and resembled those seen in weaver mice but not those in the Rolling mouse Nagoya. The results also suggest that the effects of TRH-T on the behavior of ataxic mice correlate with the extent of pathologic changes evoked in their cerebella.

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The increase in the number of epidermal melanocytes positive to the dopa reaction after birth was suppressed in C57BL/1OJ strain mice when injected with actinomycin D or Cycloheximide. On the other hand, no change was observed in the melanoblast-melanocyte population positive to the combined dopa-premelanin reaction. The initiation of melanogenesis in the skin of newborn mice, therefore, seems to require de novo transcription and translation. The increase in the number of melanocytes after treatment with α-MSH or DBc-AMP was also completely suppressed when mice were injected with actinomycin D or Cycloheximide. The results suggest that normal and hormone-induced differentiation of epidermal melanocytes requires de novo transcription and translation.

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Epizootiological observations were made on an outbreak of pneumococcal infection occurrded in 14 inbred guinea pig colonies during January to October, 1981. Monthly incidences of diseased animals ranged from 16.6 to 0%, showing the highest rate in the first month of the occurrence. Affection rates were remarkably different according to guinea pig strains, being 75% in JY-1 but 0 in JYG and Strain 2. Affected animals showed ruffled fur, dry-dirty noses, emaciated abdomen and dyspnea, and some of them were resulted in death. At necropsy, the fibrinopurulent pneumonia, pleuropneumonia and pleuritis were found as the major pathological features, and in addition, the fibrinopurulent pericarditis and peritonitis with a large amount of exudate were also observed in some cases. Streptococcus pneumoniae was isolated from nearly all the affected organs, and also from the external nares and trachea. Isolation rate from the external nares was especially high, thus 97.1% of infected guinea pigs including healthy carriers were detected by cultivation of nasal swab samples. Carrier rates of healthy animals were gradually increased from 17.2% in April to 36.5% in October, but the organism was not detected from JYG strain at all. During the observation period, vaccination, advance of weaning age of animals and administration of high vitamin C dose were taken as preventive measures of the epizootic, but no remarkable effect was obtained. The same diseased conditions were successfully produced in Hartley guinea pigs by experimental nasal infection of a pneumococcal strain isolated from this epizootic.

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Plasma lipid concentrations in NAR (Nagase Analbuminemia Rats) of 4 to 52 weeks old were examined. Plasma enzymes of NAR were also measured in relation to liver function. The concentrations of total lipid, total cholesterol, phospholipid and triglyceride tended to be increased in NAR, while that of non-esterified fatty acid (NEFA) was decreased. The lipid levels (except NEFA) were especially high in female adult NAR, and they were increased with aging. The effect of 17β-estradiol or testosterone administration on serum lipid concentrations was studied in gonadectomized NAR. Administration of 17β-estradiol to gonadecto-mized NAR increased lipid concentrations, while testosterone administration did not affect lipid levels. The effect of albumin injection on lipid concentrations in female NAR was also investigated. Albumin treatment to female NAR lowered serum lipid concentrations. Plasma glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactate dehydrogenase and leucine aminopeptidase activities were higher in NAR than in normal rats. Plasma alkaline phosphatase and cholinesterase activities of NAR were similar to those of normal rats.

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The length and weight of gastrointestinal tracts including contents of ten week old male pikas (Ochotona rufescens rufescens) and suncus (suncus murinus) were measured and they were investigated and compared with those of millardias, ICR-mice and Wistar-rats. The length from the duodenum to the anus of pikas was much longer and the weight from the stomach to the anus was about 16g per 100g of body weight. The weight of cecum was about 7g per body weight and they were heavier than those of other species. The length from the duodenum to the anus of the suncus was short but the weight of the small intestine plus colon and rectum per body weight did not differ from that of other species. The suncus has no cecum but the weight from the stomach to the anus was almost the same as that of rats.

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Cramer (1981) reported that Pg-1 (urinary pepsinogen) in the rat was loosely linked with albinism in the linkage group I. We performed a three point test on the loci of pg-1, c, and Hbb. We could reconfirm that pg-1 was autosomal trait with two co-dominant alleles of pg-1^a and pg-1^b. But in progeny of ( (WF×IS) ×WF) backcross, pg-1 was linked to neither c nor Hbb, while a close linkage between c and Hbb was detected. Also pg-1 was not linked to Mup-1 (LG II), a (LG IV), Es-3 (LG V), and h (LG VI) . pg-1 will be one of the most valuable genetic markers of the rats, since pg-1 was highly polymorphic among inbred strains of rats, and not linked to LG I, II, IV, V, and VI.

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