A new selective medium for isolation of Corynebacterium kutscheri (CK) from animals suffering subclinical infection was made by adding furazolidone, nalidixic acid and corimycin to the heart infusion agar base, this being named FNC agar. The FNC agar inhibited the growth of gram-negative rods, Pseudomonas aeruginosa, Proteus sp. and gram-positive cocci but did not affect the growth of CK. When this medium was used to isolate CK from the oral cavity and cecal contents of mice and rats, two of 6 conventional mouse colonies and three of 8 conventional rat colonies were found to be infected, with isolation of the organism from 19 mice and 12 rats in total. The animals showed neither clinical signs nor lesions, but the antibody was positive in 11 mice and 10 rats. In mice and rats inoculated orally with 4×10⁸ and 1×10⁹ organisms, respectively, CK was isolated for 20 weeks post-inoculation by use FNC agar. The isolation rate of the organism was the highest in the oral cavities of both inoculated mice and rats, and also in the submaxillary lymph nodes of the inoculated rats. The organism was also recovered from the cecal contents of more than half of the inoculated mice and rats. Thus, it was considered that FNC agar was useful in isolating CK from the oral cavity and cecal contents of mice and rats with subclinical infection of the organism.

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The acne-like inflammatory model was produced in the ears of male Sprague-Dawley rats by subcutaneous injection of 140μg of heat killed Propionibacterium acnes (P. acnes) . Ear thickness was measured as an index of inflammatory strength, using a micro indicator once every day for the first week, then every other day until the 35 th day. Animals were sacrificed and ears were excised for histological study. The tissue was stained with Hematoxylin and Eosin to investigate the state of inflammation. At the same time, P, acnes was stained specificlly by enzyme labelled antibody to study the localization of the injected bacteria body. When thickness of rat ears was measured, more than a doubling of control ear was observed with maximum swelling on the second day. The ear thickness decreased to 1.5 times control levels at 5 th day, then remained with no change for 35 days. Histological study revealed remarkable inflammatory infiltration of lymphocytes and neutrophils at the swelling site. Polynucleocyte was major infiltr ated cells until 24 hours, and then mononucleocyte was principal after 24 hours. In the tissue excised at 6 hours after injection, a temporary characteristic infiltration of eosinophils was observed. When the tissue at 35 th day was stained by enzyme labelled antibody, it revealed that the antigen of P. acnes existed among the cells at the site of infiltration and in mononucleocytes. This inflammatory model is considered to be a valuble experimental animal model for acne vulagaris with granulomatous inflammation.

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The hemagglutinating-inhibition (HI) test was used to detect antibodies for Theiler's murine encephalomyelitis virus (TMEV), and the virus was isolated from sero-positive mice derived from colonies in Japan. HI antibody was detected in conventional mice (38.7%; 137/354) at titers ranging from 1: 8 to 1: 512, but it not in SPF mice (0/90) . To isolate the virus, weanling mice inoculated intracerebrally with samples obtained from sero-positive mice were sacrificed and 10% brain homogenates were subcultured. New isolates designated as YOC and AB strains were obtained, and their physicochemical and biological properties were characterized. The results indicated that the new isolates were similar to Theiler's original (TO) strain according to the following observations of persistent paralysis of the hind limbs, resistance to ether treatment, a particle size of 1050 nm in diameter, stability at pH 3, a density of 1.35g/cm³ and three major and one minor viral proteins, (VPO; 38 Kd, VP 1; 33 Kd, VP 2; 32 Kd, VP 3; 25 Kd) . Immunoblotting analysis also showed that VP 2 of YOC and encephalomyocarditis virus of the Cardiovirus group, reacted strongly with the antisera against the viruses as well as with the GDVII strain. These results suggest that TMEV infection does exist in conventional mouse colonies in Japan, and that these viruses resemble the TO strain of TMEV.

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To establish an enzyme-linked immunosorbent assay (ELISA) technique for the serological diagnosis of infections caused by Bordetella bronchiseptica (B. bronchiseptica) in guinea pigs, the authors recently assessed the usefulness of three antigen preparations derived from the bacterial cell components: sonication antigen (S-Ag), cell surface antigen (C-Ag) and lipopolysaccharide antigen (L-Ag) . The use of S-Ag for ELISA resulted in the most sensitive detection of the antibody to B. bronchiseptica from guinea pig sera immunized with killed bacteria and sera derived from naturally infected guinea pigs. Like C-Ag, S-Ag was highly specific, showing no cross-reactivity with Pasteurella multocida. Assessment of antibody formations in animals with experimentally induced infection using the three antigen preparations revealed that the antibody to S-Ag was formed earlier than antibodies to the other two antigen preparations following growth of the bacterium in the lungs. These results indicate that ELISA with S-Ag as an antigen is a useful tool for the serological diagnosis of infection by B. bronchiseptica.

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The energy values of commercial laboratory animal diets have been customarily calculated by applying physiological fuel values (PFV) in this country. In order to ascertain accuracy of this application, apparent digestibility of crude protein, crude fat, nitrogen-free extracts (NFE), carbohydrate (NFE+crude fiber) and nitrogen-corrected metabolizable energy (MEn) of 10 commercial diets were determined using rats, dogs, rabbits and guinea pigs, respectively, and true digestibility of crude protein and crude fat of 12 feed ingredients was determined using rats. Apparent digestibility of the nutrients in the diets decreased with an increase in the crude fiber content of the diets. MEn values of the diets ranged between 2.18 and 3.75 kcal per g dry matter depending upon the crude fiber content of the diets. The energy values of the 10 diets calculated using PFV values of 4 kcal/g for protein and carbohydrate and 9 kcal/g for fat were compared with each MEn. The calculated values were 1.04 to 1.39 times higher than those of the respective MEn. All of the diets and most feed ingredients did not show high digestibility of nutrients assumed for the application of PFV. Therefore, it is concluded that application of PFV to the diets results in over-estimation of energy values and use of PFV for commercial laboratory diets in our country is not warranted. It is advisable to use MEn to evaluate energy value of commercial laboratory animal diets.

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Mean level and its variability of mean arterial pressure (MAP) were studied in 25 unanesthetized rabbits aged 6, 12, 18, 24 and 30 months. They were selected from the same large colony and bred with an ordinary rabbit food under a given environmental conditions. MAP in the aortic arch was continuously monitored with a cathetertransducer system for 3 hrs. Mean (M) and variance (V) of MAP for 3 hrs were not significantly altered with aging (p>0.05, Kruskal-Wallis' multi-sample test) . Intraanimal variations of the M and SD were small. Most of histograms of MAP for 3 hrs shows an exaggerated mode at any age. Distribution pattern of the histogram was not specific to age. These suggest that responsiveness of the baroreflex system should not be affected by aging from 6 to 30 months.

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Using the simplified method for judging visual function of the cynomolgus monkey that was established by the present authors (Suzuki et al., 1988), forty-four cynomolgus monkeys with normal ophthalmoscopic findings, eleven monkeys with macula degeneration and thirteen monkeys with peripheral retinal degeneration were examined for their visual function. It was demonstrated that the monkeys with macula degeneration were inferior in their visual function to the monkeys with normal fundus. In addition, the degree of visual function varied with the degree of macula degeneration. The monkeys with peripheral retinal degeneration showed about the same degree in their visual function as the monkeys with normal fundus.

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Spontaneous granulomas developed frequently in the bone marrow of Slc: Wistar female rats over 19 weeks of age, whereas none did in JCL: SD and Slc: SD rats of either sex. These granulomas were composed histologically of epithelioid cells and macrophages clustered mostly in the center and lymphocytes and plasma cells located in the periphery, and they contained neither microorganisms nor foreign bodies. Ovariectomy of Slc: Wistar rats at 6 weeks of age resulted in a significant decrease in the incidence and size of bone marrow granulomas at 20 and 24 weeks of age. It is concluded that two factors, the strain of rats and female sex hormone, contribute to the pathogenesis of bone marrow granulomas-the former as a hereditary disposition and the latter as a promoter.

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To elucidate the possible participation of the Mtv-2gene in the background factors relevant to mammary tumorigenesis, DDD/1-Miv-2/Mtu-2 (DDD-Mtv-2) congenic and DDD/1 background mice were compared for endocrine and immune organs, mammary gland development, expression of mouse mammary tumor virus (MMTV) -gp 52 antigen, hyperplastic alveolar nodules (HAN) and mammary tumor incidence. The congenic strain had been established by introducing Mtv-2 from GRS/AJms (GR) into DDD/1 mice by repeated 12 backcrosses. Body, thymus, spleen, uterus, ovary, adrenal and pituitary weights, histology of the ovary and mammary gland development showed no differences ascribable to Mtv-2 between both strains of mice at 4, 6 and 12 months of age. In contrast, MMTV-gp 52 antigen expression, HAN and mammary tumor occurred in DDD-Mtv-2 but not in DDD/1 mice. These results showed that the Mtv-2 gene stimulates mammary tumorigenesis by constitutional production of endogenious MMTV which transforms mammary epithelial cells but not by influencing the background factors relevant to mammary tumorigenesis. Furthermore, the expression of Mtv-2 appeared to be lower on the DDD/1 than on the GR background.

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Effects of the mandibular gland ectomy and environmental temperature to pups in Jcl: ICR mice were studied. In normal environmental animal room (A room Tem. 23±2°C, R. H. 50±10%), the mammary gland weights of lactating mothers and the body weights of pups in sialoadenectomized groups were slightly smaller than that of control groups during lactating period, whereas the eyelid opening of pups was not different between both groups and all pups exhibited complete eyelid opening on 14th day after birth. On the other hand, in cold environmental animal room (B room; Tem. 15±2°C, R. H. 60±20%), the mammary gland weights of lactating mothers and the body weights of pups in sialoadenectomized groups were smaller than that of sialoadenectomized groups in A room and the eyelid opening of pups was conciderably delayed when compared with that of control groups. The pups exhibited complete eyelid opening at 16th day after birth. These results were caused by mandibular gland ectomy and considered to be easily influenced by environmental conditions.

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Ovarian bursal membranes were dissected using a bipolar coagulator during embryo transfer to the oviducts of pseudopregnant female mice and rats. The bipolar coagulator allowed accurate, fine coagulation of small vessels and wide dissection of ovarian bursal membranes without damage to the oviducts or ovaries.

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Eight inbred mouse strains were examined for their reactivity to the induction of antinucleolar autoantibody (AnuA) by mercuric chloride (MC) . According to the positive ratio and titer of AnuA induced, the strains were grouped into high-, moderate-, low-, and non-responders. Since the susceptibilities to MC were different among strains having the same H-2 haplotype, involvement of H-2 unlinked gene (s) in AnuA induction by MC was suggested.

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Mouse embryos (8-16 cells) were collected from Sendai virus (SV) -infected mice at 5 or 7 weeks after inoculation. All donors having embryo (s) were positive when tested by CF test or ELISA for SV antibody at the time of embryo collection. Most of the morphologically normal embryos developed (90.6%, 259/286) to morulae or blastocysts after culture for 26-28hr. A total of 76 embryos cultured were transferred to the uteri of SV-free pseudopregnant recipients. Forty-seven young were obtained from these recipients (61.8% of development rate) and 46 young were successfully reared up to 10 th week of age. All the recipients and the young were negative by testing SV antibody. These results indicate that the embryo transfer technique is useful for cleaning of SV-infected mice.

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Pathological examination of two 12-week-old male Sprague-Dawley rats revealed bending of the sternebrae. Grossly, the sternebrae distal to the third sternebra were bent towards the underside, and the episternal extremity was turned towards the head. Microscopically, the 4th sternebra was observed to have slipped behind the third sternebra, and fractures of the episternal cortex and slanting of the episternal cartilage were also observed.

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Pathological examination of a 4-week-old male Sprague-Dawley rat revealed hypoplasia of the left kidney. Grossly, the left kidney exhibited hypoplasia associated with absence of the ureter on the same side. Histologically, components of the cortex and medulla were mingled in the tissue, and the glomeruli and convoluted tubules were scattered in disorder, and connective tissue proliferation was also observed. The papilla and pelvis could not be identified.

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