Changes in histomorphometric values of iliac trabecular bone and serum biochemical constituents related to bone metabolism in normal beagle dogs during growth were examined. A total of 90 dogs (male; 46, female; 44) aged 3, 6, 9, 12 and 24 months, were used. Each dog was injected with tetracycline hydrochloride and calcein for double bone labeling in order to quantitatively measure dynamic as well as static parameters in bone histomorphometry and a part of the ilium was later removed. The measurements on cancellous bone areas of undecalcified iliac sections were performed with a semiautomatic image analyzer. There were no sex significant differences in histomorphometric values except for mineralization lag time at the age of 3 months. In the static parameters, bone volume and mean trabecular thickness increased from 3 to 9 months of age. Bone surface area and mean osteoid thickness increased up to 6 months. Osteoid volume and osteoid surface area decreased up to 6 months of age. As to the dynamic parameters, the mineral apposition and bone formation rates decreased from 3 to 12 months of age. Mineralization lag time increased from 3 to 9 months of age. However, high bone surface area values in both sexes and low osteoid thickness values in females were seen at the ages of 9 and 12 months. Low values of trabecular thickness in both sexes, osteoid thickness and mineralization lag time in males and mineral apposition rate in females were also noted at the age of 12 months. Serum total calcium did not show any specific tendency. Serum phosphorus, alkaline phosphatase activity and osteocalcin decreased from 3 to 12 or 24 months of age except for the high value of alkaline phosphatase activity at 12 months of age in males. Parathyroid hormone and calcitonin increased from 3 to 9 or 12 months of age. In conclusion, the results indicate that histomorphometric values of iliac trabecular bone and the serum biochemical values reflect alternations in bone metabolism in normal beagle dogs during growth in which change occurs rapidly at 6 or 9 months, and that these changes continue until adulthood is reached at the age of 24 months.

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Urine volume (UV), Glomerular filtration rate (GFR) and Fraction of reabsorption (FR) of water, Ca, IP, Na⁺, K⁺, Cl^-, Glu and UN, which are significant in kidney function analysis, were investigated and compared in three rat strains (WI, SD and F344) . UV/body weight ratios were higher in SD rats as compared to other strains. The GFR difference was not significant, but the FRH₂O difference was significant in three rat strains. FR of Ca, K⁺ and Glu showed no significant differences in three different rat strains. SD and F344 were significantly lower than WI in FR of IP. FR of Na⁺, Cl^- and UN were significantly different in three rat strains without Cl^- between SD and F344, and UN between WI and SD.

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Effects of restricted feeding on the growth of laboratory-bred male cynomolgus monkeys (Macaca fascicularis) aged between one year and four years were studied morphometrically. A series of 11 variables representing physical elements were measured. Before 2.5 years of age, the amount of commercial diet (Type AS, 382kca1/100g and 28.1% of crude protein, Oriental Yeast Co. Ltd.) per day was restricted to 50g (group A), 30g (group B) or 20g (group C) and increased to 100g (group A), 50g (group B) or 40g (group C) respectively at 2.5 years old. Throughout the experimental period ca 100g of apples and oranges per day were provided. Significant differences in body weight between group A and C were detected excepting the early period of the experiment. Although the slight suppression in weight gain was observed in group B during the second trimester of the experiment, body weight increased gradually after increasing the amount of food and no significant difference from A was observed at four years of age. The minimum requirement of diets is judged to be 30g/day before two years old and 50g/day over two years old in the laboratory-bred male cynomolgus monkey. Moreover, the suppressive effects of restricted feeding were most significant on the growth of the limbs and, secondarily, on the growth of the trunk. Practically no effect on the growth of the head was observed.

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The scent gland and ordinary sebaceous gland of Syrian hamsters and Monogolian gerbils were studied using lectin histochemistry. Male scent glands were larger in size than those of female in both species, but in histochemistry there was no distinct difference between both sexes. Histologically, the scent gland of Syrian hamsters had a strong resemblance to ordinary sebaceous glands, compared to that of Mongolian gerbils. Since the duct of Syrian hamsters was very short, it is difficult to distinguish the duct from the infundibulum. The duct and infudibulum of Mongolian gerbils were larger in diameter than those of Syrian hamsters. The duct widely opened to dermis. Seven lectins (ConA, RCA I, PNA, SBA, UEA-I, DBA and WGA) were used in this study. All of them labelled the differentiated cells of acinus in Syrian hamsters, although SBA did not label those cells in Monolian gerbils. The cells of the duct in Syrian hamsters and Mongolian gerbils were not labelled with SBA. Ordinary sebaceous glands in both species were labelled with all seven lectins. Lectin-binding patterns of scent glands and sebaceous glands were similar in Syrian hamsters. While, in Mongolian gerbils, SBA-binding patterns were different between scent and sebaceous glands. Histologically, the scent gland of Syrian hamsters resembles the sebaceous gland. Therefore, there is a possibility that the scent gland of Syrian hamsters still provides some properties similar to sebaceous gland.

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In order to eliminate Pseudomonas (P.) aeruginosa from a contaminated nude mouse colony, the following procedures were carried out: improvement of environmental sanitation using an effective disinfectant against the organism; supply of tap water acidified with hydrochloric acid at pH2.5 -3.0; elimination of mice positive in isolation of P. aeruginosa from the nude mouse colony. The experimental results indicated that P. aeruginosa were successfully eliminated from the colony through a combination of the above three procedures.

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The effects of restricted feeding on hematological and serum biochemical values were studied in laboratory-bred male cynomolgus monkeys (Macaca fascicularis) aged between one year and four years. In animals younger than 2.5 years old, the amount of commercial diet (Type AS, Oriental Yeast Co. Ltd.) given per day was restricted to 50 g (group A), 30 g (group B) or 20 g (group C) and increased to 100 g (group A), 50 g (group B) or 40 g (group C) at 2.5 years old. Throughout the experimental period, about 100 g per day of apples and oranges were fed to the animals. Differences in red blood cell counts, hematocrit values and hemoglobin concentrations between groups A and C were detected in the middle period of the experiment. The function of hematogenesis may be suppressed by restricted feeding. A significant increase in serum triglyceride concentration in group C and slight increase in group B were observed during the second trimester of the experiment. A decrease in serum alkaline phosphatase activities in group C during the same period suggests that restricted feeding has a suppressive effect on bone growth. The results obtained by hematological and serum biochemical observations in this study are in good agreement with the previous somatometric study [10] .

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Lectin-binding patterns of vomeronasal respiratory epithelium (VRE) in rats were histochemically examined with 21 biotinylated-lectins. The VRE consists of ciliated and basal cells. The majority of ciliated cells had light cytoplasm, and the others were dark cells seemingly degenerating. On the free surface of the VRE, 16 lectins showed moderate to intense staining. Eight and 10 lectins showed moderate to intense staining in the cytoplasm of light and dark cells, respectively. Five out of them showed the staining only in the degenerating dark cells. On the other hand, Jacalin showed the various grades of staining in the light cells. In the basal cells, 5 lectins showed moderate staining. These lectins also showed moderate to intense staining in the light cells. In summary, the kinds of glycoconjugates on the free surface were the most numerous in number in the VRE, and the lectin-staining underwent some changes with the functional state or degree of maturation in the ciliated cells.

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Alloxan-diabetic rats were kept on an ordinary or 0.25% cholesterol supplemented diet for up to 12 months, and changes in the serum lipid and lipoprotein levels were examined. The diabetic rats showed IRI levels of 3-S IU/ml, which were 1/5-1/10 that of the normal rats, and about 10 times higher serum glucose levels than the normal rats. The diabetic rats consumed 1.5-2 fold amounts of diet but their body weights were almost constant. The diabetic rats showed marked hyperlipidemia, especially in the cholesterol and triglyceride levels. The phospholipid level also increased but for a lesser extent and the c/p ratio increased. The serum lipoprotein levels increased in the diabetic rats, 5-10 times in the ordinary diet fed groups and 10-20 times in the cholesterol diet fed groups. Chylomicron, VLDL, IDL and LDL increased but HDL decreased. These changes were more significant in the diabetic rats fed the cholesterol diet. The triglyceride levels in the lipoprotein fractions increased in the diabetic rats, but the increase in cholesterol was more significant and the relative composition ratios of triglyceride decreased. The composition ratios of phospholipids, however, remained almost constant in all the lipoprotein fractions. The increase in IDL, especially cholesterol in the IDL fraction, was remarkable in the diabetic rats. The responsiveness of the diabetic rat VLDL to lipoprotein lipase (release of free fatty acids) was less than a half of that of the normal rat VLDL. In conclusion, the diabetic rats showed an increase in triglyceride but more significant increase in cholesterol in the lipoprotein fractions. These changes in serum lipid and lipoprotein levels and compositions appeared as early as 3 months after the alloxan injection and lasted for 12 months without any progress in the disturbance.

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Ehrlich ascites tumor cells (EAT cells) lack most cell surface H-2 antigens and grow in any mouse strain following intraperitoneal injection of 105 cells. With subcutaneous injection of 2×10⁷ cells, however, EAT regressed in C57BL/10 (H-2^b), BALB/c (H-2^d), NZB (H-2^d), A (H-2^a) and SJL (H-2^s) but progressed and formed a solid tumor in DBA/2 (H-2^d), C3H (H-2^k), AKR (H-2^k), CBA (H-2^k) and DBA/1 (H-2^q) . By genotype analysis, Ly haplotypes of EAT-regressive mouse strains were found to have Ly-1.2 and Ly-2.2 as common features, while EAT-progressive mouse strains had Ly-1.1 (except AKR) and Ly-2.1.

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We were able to measure bone mineral density (BMD), mean bone width and the area of the lumbar vertebrae in male African green monkeys with a dual-energy X-ray absorptiometry (DPX-α, Lunar, USA) . For analysis of spinal bone mass, mean width and area of the bone, we scanned lumbar vertebrae L3-L5 using a pediatric analysis program. We used restraining bed made of formed polystyrol to support the animal in a supine position. The precision of the measuring technique was calculated by averaging the coefficients of variance of the 5 scans obtained in 5 animals aged from 5 to 7 years. The precision values for BMD, bone width and area were 1.9%, 0.9% and 2.6%, respectively. Furthermore, age-related changes in bone measurements were demonstrated using laboratory-bred males (n=45) and, additionally, wild-originated males (n=7, estimated ages over 15 years old) . The values of B M D, bone width and area at 6 months old were about 0.3g/cm², 1.2cm and 4.5 cm² respectively. These values increased with aging to about 0.7 g/cm², 1.5 cm and 11cm² at 5 years old, respectively, and were judged to reach plateau. However, animals over 10 years old and wild-originated animals which had been kept over 10 years in our breeding colony showed rather smaller BMD and area values than the animals aged 5 to 10 years. The animals aged between 5 and 10 years seemed to have retained a peak bone mass in this primate species.

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To clarify the effects of a thermal environment on rats, histopathological changes, and temperatures in the rectum and eyes of Fischer strain rats exposed to a thermal environment of 32°C for 2 days or 7 days were investigated. Thermal exposure to 32°C induced elevations in rectal and ocular temperatures. The increased temperature levels persisted during the thermal exposure. Vacuolar degeneration surrounding the hepatic vein was observed in rat livers exposed to 32°C for 7 days. No abnormalities were observed in other organs. These results indicate that thermal exposure to 32°C induces vacuolar degeneration in hepatocytes due to the elevation of body temperature.

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We cryopreserved pronuclear stage-embryos from the Transgenic rats produced by introducing the rat GH antisense transgene, by ultrarapid freezing. The embryos were obtained by fertilization in vitro with the sperm of homozygous males for the transgene. After thawing of a part of cryopreserved embryos (97 embryos), the 40 embryos (41%) were morphologically normal, and were transferred to oviducts of recipients. All four live young (10%) obtained (one male and three females) preserved the transgene and exhibited dwarfism. We also produced the homozygous transgenic rats after brother-sister mating of those young. These results demonstrated the possibility of the cryopreservation of embryos by ultrarapid freezing for sustaining transgenic rat line.

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Inbreeding of Japanese wild rats (Rattus norvegicus) resulted in five new strains. The conception rates of wild rat strains were lower than those of inbred laboratory strains, and maternal aggressiveness was observed in some wild strains. The body size of domesticated animals was larger than that of captured ancestors. Two strains have been established as inbred strains; the MITA strain has been tamed to the level of laboratory rats, while the nature of the MITD strain is wild. The MITB strain was derived from the MITA strain as a coat color variant. The MITC and MITE strains have been bred to the F₁₅ and F₁₁ generations, respectively. The new strains can provide new genetic variations against a wild type background and might be useful for physiological and psychological experiments.

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Gross morphology of the pancreas and distribution of pancreatic ducts were investigated in 12 Jcl: Wistar rats. The pancreas consisted of a body and two (right and left) lobes. The pancreatic body was located along the cranial part of the duodenum. The right lobe extended into the duodenal ligament, while the left lobe extended toward the spleen into the gastrolienal ligament. In 9 animals, the number of ducts ranged between 3 and 10. Each duct joined the hepatoenteric duct. Two (right and left) large ducts found in all animals drained the right and left lobes. Other ducts observed in more than a half of the animals drained either the body or a part of the lobe.

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Bone mineral content and soft tissue (lean and fat) mass in living female cynomolgus monkeys were successfully measured with a dual-energy X-ray absorptiometry (DEXA; DPX-α, LUNARE, USA) . Measurements were performed using a restraining bed made of forming polystyrol with 5cm thickness to support the animal in a supine position. Accuracy of measurements was checked by using a dummy consisted by various combinations of lean, lard and ribs. The results confirmed that this system is able to measure each consitituent exactly. The percentage of fat in the soft tissue is seemed to be better index of obesity in this primate species when compared with other obesity markers such as body weight and morphometry.

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