Breeding experiment was designed to obtain diabetic strains of mice for medical researchs.
Several strains of mice were examined for diabetes, and KSB was newly found to be diabetic with consistent glycosuria in females and decreased ability of assimilation of glucse in both sexes. Such diabetic tendencies were widely observed among other strains, NC, NB, NBC and DDK. Diabetic characteristics of KK and AY were reconfirmed.
Interoduction of the Ay gene into KK by successive backcrosses was effective to breed a serious diabetic strain, KK-CA, with severe glycosuria, hyperglycemia and abnormal glucose tolerance curve. This strain will be useful as an experimental tool in the study of diabetes mellitus. The other program of the selection of severe diabetic mice from the F₂ progenies between two diabetic strains, KK and KSB, was also successful to obtain diabetic mice in the F₃, with significant effect of selection, but the breeding program was discontinued because of low fertility in successive generations.

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This experiment was carried out to confirm the differences of the milk-production curves of four strains in mice.
The mice used in this experiment were C57BL /6, C3H/He, SS and NC strains maintained in the research colony of our laboratory. The femal mice in each strain were mated at 60 days of age and these females were delivered about 80 days of age. After partutrition the number of young of each mother was kept six.
The amount of milk secreted by lactating mice was estimated by the difference of the weight of 6 young before and after 1-hour-suckling regimen following 8 hour's separation of the young from the mother. The measurement was made every other day from the 4th to the 20th day after parturition.
The average weight of young, the average gain in weight of young and the average growth rate of young on the 12th day after birth was measured. The average weight of young was showed by the average of total weight of 6 young on the birth day (W₁) and the 12th day (W₂) after birth. The average gain in weight of young was calculated by the equation, (W₂-W₁) . The growth rate of young was calculated by the equation, { (W₂-W₁) /W₁} x100.
The results obtained were as follows:
1. The milk-production curves showed the different patterns among the strains of mice. The total yield of milk obtained every other day from the 4th day to the 20th day after parturition was larger in SS and C3H/He strains than in C57BL/6 and NC strains.
2. Although the peak period of lactation varied from strain to strain, the pattern of the milkproduction curves was similar in the strains used. The amount of milk-production increased from the low levels at parturition and reached to a peak at about 14-16days. The amount, then, declined to the low level at weaning.
3. The average weight of young and the average gain in weight of young on the 12th day after birth in SS and C3H/He strains showing the higher value in total yieled of milk were better than those of C57BL/6 and NC strains.

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Susceptibility to audiogenic seizure under repeated pure sound stimulation was observed as a means of investigating the influence of noise on laboratory mice.
In this investigation, 70 male and female ICRJCL mice were used. At ages of 4 to 10 weeks, these mice were subjected to 2 minutes per day of sound stimulation with a mean intensity of 110 decibels and a frequency of 10, 000 cycle per second (cps) . They were separated into four groups : (1) stimulated every day, (2) every three days, (3) every six days, and (4) nonstimulated control.
Susceptibility to audiogenic seizure was determined by behavioral responses as given in the preliminary report. The results are summerized as follows
1) The gain in body weights of female mice subjected to repeated sound stimulations daily and every three days was less than that of the control mice. In the male mice, the body weight of the daily stimulated group differed only slightly after 10 to 16 days from that of the control.
2) It appeared that repeated sound stimulation reduced the frequency of the seizure susceptibility.
3) The susceptibility of daily stimulated mice decreased gradually. However, in the groups stimulated repeatedly every three days and every six days, the reduction in frequency was not remarkable.
4) Individual differences in seizure susceptibility according to repeated sound stimulation were evident.

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Male and female ICR-JCL mice at ages of 4 to 10 weeks were subjected to 2 minutes per day of sound stimulation with a mean intensity of 110 decibels and a frequency of 10, 000 cps. The mice were separated into four groups : (1) stimulated every day, (2) every three days, (3) every six days and (4) a non stimulated control group.
The mice were sacrificed on the day after the last sound stimulation and the blood pictures (red and white blood corpuscle counts and haematocrit, and plasma protein, glucose and ascorbic acid contents) as well as organ weights (brain, hypophysis, thyroides, adrenals, spleen testes, uterus and liver) were observed.
The results are summerized as follows :
1) White blood corpuscles in the stimulated mice decreased more remarkably than in nonstimulated controls. Howevrer, other blood factors did not differ significantly after repeated sound stimulation.
2) Hypophysis and thyroides weights in stimulated mice were greater than those of controls, while the testis and liver weights were smaller.
3) Individual differences in blood characteristics and organ weights after repeated sound stimulation were remarkable. This suggests a correlation between seizure susceptibility and adaptability in mice.

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When Japanese quails (Coturnix coturnix japonica) were kept in stainless steel cages with 1200 cm² of floor space and fed the autoclaved diets for six weeks after hatching, growth, feed intake, excreta weight, feed efficiency, protein efficiency ratio, coefficient of apparent digestibility of nitrogen, and the ratios of retention of nitrogen, calcium, magnesium and phosphorus were studied.The results obtained are summarized as follows.
1) The growth of Japanese puails fed diet A and B, which were composed mainly of commercial mixed feed for Japanese quail and for chick, respectively, were comparable. The birds gained their weight in maximum during the third week. Japanese quails of one and two weeks of age, which were fed diet A supplemented egg yolk powder for the first week after hatching, showed more weight gain than the control group. Japanese quails housed at a density of two birds per cage (lower density group) gained more body weight than those of 13 birds per cage (higher density group) . Between the normal group and the depressed group, in which growth depression was obtained by feed restriction during a week from one week of age, there was still a significant difference in the body weight at the end of the experiment.
2) Weekly feed consumption and excreta weight per 1 g of body weight were maximun during the second week. More feed consumption in the lower density population group than in the higher density group was observed.
3) Weekly feed efficiency, protein efficiency ratio and coefficient of apparent digestibility of nitrogen decreased with ages of the birds, and the ratios or coefficient cumulatively calculated for whole experimintal period were similer bet-ween both groups fed diet A and B.
4) Weekly ratios of retention of nitrogen, calcium, magnesium and phosphorus were highest during the first week after hatching. The ratio of nitrogen retention of the diet A fed group decreased until the third week and thereafter incerased considerably. In the case of the diet B fed group, the ratio of nitrogen retention decreased until the fourth week and increased in the sixth week. Ratio of cumulative nitrogen retention for six weeks of the diet A fed group was higher than that of the diet B fed group. Since the ratios of retention of calcium, magnesium and phosphorus for the diet A and the diet B fed group decreased sharply and more gradually respectively at the second or third week after hatching, cumulativer atios during six weeks were higher in the latter than in the former.

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Organ weights and tract lengths of gastrointestine of Japanese quails (Coturnix coturnix japonica) kept in stainless steel cages on the floor space of 1, 200cm² and fed the autocaved diets for 6-8 weeks after hatching were studied.
When comparing the organ weights and gastrointestinal tract lengths of male quails with those of female quails, organs of females were larger or similar than those of males except for the heart of the pellets fed groups (19-1-19-3) .
With the values per each body weight, the weight of the heart and the length of digestive tract in females were smaller than those in males, while the weights of the liver and pancreas were larger.

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After a single injection of cortisone acetate into 4-week-to 8-month-old BALB/c, DDD, ICR-JCL, ddy-SLC mice, lesions in the heart showing characterized by white flecks located predominantly on the surface of the right heart ventricle (Photo 1) were observed with a high incidence (Table 1) when the animals were killed 10 days later.
Histopathologically basophilic granular degeneration and severe destruction in myocardial fibers adjacent to the pericardium were observed (Photo 2) . Degenerated myocardial fibers were enlarged and nuclei disappeared in many of them. Many of these cells contained a number of basophilic microgranules. Rarely vacuolar and edematous degeneration was found (Photo 2) . Around the coronary artery the lesions were associated with multiplication of fibroblasts (Photo 2) . Basophilic granules in degenerated area were shown to be PAS positive and resistant to salivery digestion (Photo 7) .
By Kossa's stain multifocal calcium deposits were shown in degenerated myocardial fibers as well as in connectve tissue (Phot 5, 6) .They were associated with multiplication of fibroblasts, collagen fibers and occationally mononuclear round cells.
Such cardiac lesions were considered to be due to the dystrophic calcification and not to calcareous metastasis because calcification was not observed in elastic fibers of alveolar wall, renal collecting ducts and stomachal mucous membrane. Calcium and inorganic phosphorus contents were not elevated in the sera of the affected mice (Table 2) .
No organisms were detected from affected lesion by incubating on horse blood agar. Serum agglutinin against Corynebacterium kutscheri and Salmonella enteritidis and CF antibodies to Tyzzer's agent and MHV (Pr) were negative with 1 : 8 sera of affected mice, while CF antibodies to Sendai virus were positive in some cases. In mice which were injected intravenously with 0.1 ml of affected heart emulsion (1: 20) no cardiac lesions were observed. However, further observations are needed to determine whether HVJ infection is involved for producing the heart lesion.

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