The hearts of BALB/c mice are known to acquire pronounced greyish white spots (cardiac white spots) . BALB/c male mice were examined for the relationship between the incidence of cardiac white spots and weekly age, and compared with DDY male mice. During the observation period of 0.4-30 weeks, cardiac white spots on the right ventricle of BALB/c mice were first detected at three weeks (6 of 20 mice; 30%), and the maximal incidence of cardiac white spots was obtained at nine weeks (39 of 44 mice; 88%) . In contrast, DDY mice were completely devoid of cardiac spots. Histopathologically, the cardiac spots were dystrophic calcinosis. There were significant increases in the relative organ weights of the heart and kidney of BALB/c mice compared with those of DDY mice. However, there was no significant difference between BALB/c and DDY mice in serum calcium concentration or histological characteristics of the parathyroid gland or bone marrow. The cardiac white spots of BALB/c mice were considered to be controlled by genetic susceptibility that occurred spontaneously with aging. The results described here suggest that BALB/c mice are adequate experimental animals for the study of myocardial disease that occurs spontaneously.

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Using the halved morulae of mice obtained with microsurgical technique, the following two experiments were performed. 1) Sexing of half-embryos by chromosomal analysis and transfer of the half-embryos after determining the sex of the other monozygotic half. One half of the bisected embryo was cultured in Colcemid solution (0.04μg/ml) to be ensured for chromosomal preparation. More than 50% (152/270) of the blastulated embryos from the halves could be sexed by direct sex chromosome analysis. Thirty-nine of the half-embryos of which the co-twin halves were sexed, were transplanted in to the uterine horns of 18 pseudopregnant mice, and twelve became pregnant. The autopsies of them on Day 18 to 20 of pregnancy, revealed the presence of 16 fetuses. The morphological sex of these fetuses thus obtained coincided completely with the previous judgement based on the chromosomal sexing. 2) Production of chimeras of defined sex composition by aggregating two half-morulae of defined sex. Out of 147 pairs of halfmorulae of two different strains (ICR and C3H/He), which were replaced in pairs into empty zona pellucidae, 107 (72.8%) were aggregated successfully and developed in vitro into full expanding blastocysts of typical form. Among the 107 aggregate blastocysts, 31 were sexed for both component embryos by chromosomal analysis on the co-twin half-embryos. When these 31 blastocysts were transferred, 11 living offspring including 4 chimeras were obtained. Transfer of 12 _??_↔ _??_ and 5 _??_↔_??_ aggregate blastocysts resulted in 8 males and 1 female, respectively. As a result of transfer of 14 _??_↔_??_ aggregate blastocysts, 1 male of chimeric phenotype and 1 female of albino“single-type” offspring were obtained.

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The behavioral mutant“back-drawer”of Japanese quail is characterized by crouching and back-drawing action with the neck bending ventrally and occasional forward rolling. The abnormal behavior appears from hatching to 8 weeks of age. Back-drawers were classified into three types: (1) thouse showing the abnormality at hatching and dies within 5 days; (2) those showing the abnormality after 2 weeks of age and dies shortly thdreafter; and (3) long survivors suffering from abnormal behavior, and showing gradual recovery. Back-drawer males are infertile when showing the abnormality, but can produce progeny after recovery. In contrast, the females tend to have a short life span and lack reproductive ability. Genetic analyses have indicated that this mutant character is controlled by 2 pairs of autosomal recessive genes.

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We describe the relative growth in infant cynomolgus monkeys (Macaca fascicularis) . The multivariate analyses using the principal component analysis and multivariate allometric analysis were applied to biometrical data of laboratory-bred cynomolgus monkeys aged from birth to 12 weeks. All the animals had been bred and reared under uniform environmental conditions at Tsukuba Primate Center for Medical Science, N. I. H., Japan. As the result of the principal component analysis, the cumulative contribution ratio of the 1st and 2nd principal components (PC1 and PC2) accounted for 88.2% and 85.7% in males and females, respectively. This indicates that the morphologic traits (15 traits) grow normally in size, but the analysis did not detect any differences in growth rate among the traits. So, the multivariate allometric analysis was applied to the same data. The traits concerning the face and truck showed relatively high growth rates compared to head breadth, whereas the limbs and arms grew slowly.

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Vascular changes in the hydronephrotic glomeruli of rats were examined using corrosion casts, India ink injection and histological methods. In severe cases, the diameter of the glomerular capillary conglomerations decreased to 40-90 μm as a result of glomerular atrophy. The capillaries of these glomeruli also had reduced diameters, and were strangulated and torn off to varying degrees. The intact capillary network of the renal medulla was destroyed and the normal alignment of capillaries parallel to the tubules was lost. These morphological characteristics may account in part for the difficulty in glomerular capillary blood circulation.

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Among nine laboratory shrew lines originating from the Japanese islands (Nag, Tok, TKU, Ize, Tr and OKI lines), West Java (Bog), Bangladesh (BAN) and Sri Lanka (SRI), Nag, Tr and Bog were fixed with Amy-1^b and SRI with Amy-1^a. The remaining lines were still highly polymorphic with the two alleles. A new electrophoretic band C was found in the BAN line and concluded to be expressed by a codominant allele, Arty-1^c, which was carried by a single heterozygous female from among eleven wild shrews of the original breeding stock. In most local populations of the Asian shrews surveyed, Amy-1^b was more common than Amy-1^a. The Sri Lanka population was clearly distinguishable from the others, being nearly fixed with Amy-l^a. The C band was found in eleven (one homozygous) of 86 wild shrews caught in Bangladesh. Of a total of 234 wild shrews collected from four Japanese and two Indonesian islands, Bangladesh, and Sri Lanka, only two showed different AMY-bands from AMY-A, -B and -C, and such bands were not found in the laboratory-bred shrews examined.

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The incidence of the interfrontal bone in mice differs between strains, being high in C57BL/6 and low in BALB/c. In the present study, aggregation chimeras (C57BL↔BALB) were examined to reveal whether or not genetically different cells interact in the morphogenesis of the interfronatal bone. In C57BL/6 mice, large interfrontal bones appeared in almost all aninals, whereas in BALB/c and reciprocal F₁ crosses (C57BL×BALB, BALB×C57BL), large bones were seldom observed while tiny bones at the inside of the skull appeared at a low incidence. In contrast, chimeras frequently had large interfrontal bones, the size of which varied considerably. Based on the degree of chimerism as determined by coat color mosaicism and glucose phosphate isomerase (GPI) analysis of tissues, the chimeric mice containing a dominant population of C57BL cells had large interfrontal bones, while those with a predominance of BALB cells had no bone or had tiny ones. The results indicated that the appearance of the interfrontal bone corresponded with the population of the C57BL cells occupying the skeletal rudiment, and that there was no interaction between C57BL cells and BALB cells in the morphogenesis of the interfrontal bone.

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Enterosiderosis in both SPF Hartley guinea pigs and vitamin C-deficient animals of the same strain were studied by light and electron microscopy. Enterosiderosis was detected in all animals in the present study. Macrophages, enclosing yellowish-brown pigments and erythrocytes, appeared in the lamina propria of the intestinal mucosa, mainly in the cecum. These pigments in the macrophages were positive for Prussian blue, PAS and the Nile blue reaction. Residual bodies containing highly electron-dense ferritin-like particles, lipofuscin granules and debris of phagocytized erythrocytes were found by electron microscopy in the macrophages. In vitamin C-deficient guinea pigs, the number of macrophages, including the same above pigments, appeared in the lamina propria of the intestinal mucosa, and there was severe enterosiderosis. In the absorptive cells of the intestinal mucous menbrane, granules positive for the Prussian blue reaction appeared only in the duodenum. These findings strongly suggest that the pigments in the macrophages in enterosiderosis of the guinea pigs were mixtures of iron and lipofuscin granules and that the iron is derived from erythrocytes phagocytized by macrophages in the lamina propria, but not from iron absorbed by epithelial cells.

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A total of 13 forty-day-old male Japanese quails had free access to a atherogenic diet containing 15% corn oil and 2% cholesterol or commercial basal diet for 3 months. Birds fed basal diet showed no significant intimal lesions. These birds had two types of cells, i.e. smooth muscle cell and fibroblast-like cell, in the tunica media of the ascending aorta. While fat-fed birds showed maked lipid-rich intimal lesions in the ascending aorta but not in the abdominal aorta. Some macrophage-derived foam cells, which were stained for lysozyme and OKM1, were demonstrated in the superficial portion of the thickened intima. The majority of the cells in the lipid-rich thickened intima showed ultrastructural character of fibloblast-like cells with or without lipid droplets. Alpha-1-antichymotrypsin was positie for fibroblast-like cells in the thickened intima but not for those in the tunica media of the ascending aorta. These results suggest that metaplasia of the medial fibroblast-like cells is responsible for the development of atherosclerosis in the quail.

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We have studied a female mongrel dog found in Kanagawa Prefecture, Japan. This dog was selected and examined thoroughly because she naturally maintained a high glutathione (GSH) concentration in her erythrocytes and did not exhibit any clinical signs or hematologic disorders. Erythrocytes from this animal demonstrated high K and low Na concentrations, as well as accumulation of the amino acids, glutamic acid, aspartic acid and glutamine. The Na, K-ATPase activity was also markedly elevated and the osmotic fragility of the dog's erythrocytes was found to be significantly increased. Crossbreeding of our dog with a normal dog and also with a heterozygous carrier dog revealed that the genetic abnormality possessed by our dog is transmitted as an autosomal recessive trait. All of the clinical data obtained from studying this animal strongly suggest that it possesses a genetic trait similar to that of the HK dogs previously described by Maede.

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A single injection of hypertonic saline produced brain lesions with corresponding nervous signs in mice. The lesions were most often found in the hippocampus and were characterized by degeneration and loss of pyramidal cells. They could be induced effectively by a single administration of 20 ml of 25% saline/kg orally or of 30 ml of 8.5% saline/kg intraperitoneally. This simple experimental system seems to be a useful model of central nervous system involvement.

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Mean litter size in gad/gad females was significantly lower than in normal females (+/+ and gad/+) in intra- and inter-strain crosses. The reduction in litter size was not dependent on the genotypes of the males, but could be attributed to the gad/gad females themselves. The numbers of corpora lutea and implants in gad/gad females were slightly reduced as compared with those in the controls, but the number of live fetuses was significantly lower than that in normal females 14 days after copulation (P<0.02) . Hence, reduced litter size in gad/gad females was accounted for mostly by embryonic and fetal death after implantation, which was inferred to be due to impaired uterine function.

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A serological survey was carried out to examine the presence of antibodies against feline leukemia virus (FeLV) and feline oncornavirus-associated cell membrane antigen (FOCMA) in 208 cat sera collected at Teikyo University School of Medicine. Seven cats (3.4%) were positive for FeLV antibodies by enzyme-linked immunosorbent assay whereas no cat was positive for FOCMA antibody by indirect membrane immunofluorescent test. Anemia, leukemia and/or lymphoma formation were not observed in these FeLV antibody-positive cats. But among these seven cats, three were positive for toxoplasma antibodies. One of them was also positive for Chlamydia psittaci antibody and it died in pneumonia. Among the four toxoplasma antibody-negative cats, one was died in eosinophilic granuloma. Furthermore, two of three cats, which were used for experiments, had cold and took therapy.

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