Five male cats were used to examine utilization of nitrogen and macro-minerals (calcium, phosphorus and magnesium) in response to food restriction and subsequent repletion. For the first week, each cat was daily given 135 g of dry cat food (baseline period), followed by a restriction period for 1 week; during this period, daily food was individually restricted to 40% of the amount consumed by each cat during the baseline period. Food provision was then returned to the daily 135 g for the final week (recovery period). Fecal weight changed in association with changes in daily food intake, but urine volume changed less with the periods. Fecal and urinary excretion of nitrogen rapidly decreased during the restriction period, but the decreases were smaller than the decrease in nitrogen intake, leading to net nitrogen loss. On the other hand, the food restriction had relatively smaller effects on retention of macro-minerals, and calcium retention was not significantly affected by daily food provision, although the plasma concentration of magnesium was increased during the restriction period and tended to return during the recovery period. Nitrogen retention was increased by the removal of food restriction, but did not exceed the original level of nitrogen retention during the baseline period. These findings suggested that restriction of diet had a serious effect on nitrogen balance, and the impaired protein nutrition might not be easily recovered by subsequent nutritional repletion.

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The capacity for reproduction in germfree mice remain inferior to their conventional counterparts even after improvement of feed and other such rearing conditions. The authors provide evidence of increased reproductive capacity in germfree mice following association with bacteria. Estrous cycles were normalized in female mice accidentally contaminated with bacteria, and in mice given fecal suspensions of the accidentally contaminated mice per os. Significant rises were seen in their copulation and implantation rates, reaching levels comparable to values in conventional mice. In male mice, bacterial contamination induced significant increase in sperm motility. Bacteria were identified in the feces of the contaminated mice, and reproductive capacity was examined in mice associated with the identified bacteria. As a result, normalization of the estrous cycle, and rises in copulation and implantation rates were noted in B. distasonis and C. perfringens di-associated mice. Values from B. subtilis mono-associated mice were comparable to those in germfree mice. These results from our accidental contamination indicate that B. distasonis and C. perfringens are capable of normalizing estrous cycles in female germfree mice, and in increasing their reproductive capacity by raising their rates of copulation and implantation.

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Age-related changes in major lymphocyte subsets were analyzed in 195 cynomolgus monkeys (Macaca fascicularis) aged from one month to 31 years. The percentages of CD20⁺ B cells in peripheral blood lymphocytes (PBL) decreased with age to five years of age, but after that, no significant change was observed. The percentages of CD16⁺ NK cells gradually increased during the first five years and reached the peak at from four to ten years of age, whereas the percentages of CD3⁺ T cells in PBL were relatively constant throughout the life. Among the T cells, the CD4⁺ CD8^- T cells decreased, but CD4^- CD8⁺ T cells increased within the first decade of life. We further analyzed the expressions of CD28 and CD29 molecules on T cells to determine the relation between age-related activation and phenotypic changes. Almost all CD4⁺ CD8^- T cells (>90%) were CD28⁺ at all ages analyzed, but a clear age-related decrease in CD28 expression was demonstrated in CD4^- CD8⁺ T cells during the first ten years. In the case of CD29 expression, age-related increases in CD29^hi cells were apparent in both CD4 ⁺ CD8^- and CD4^- CD8⁺ T cells during the first ten years. The percentages of CD29^hi cells, however, were higher in CD4^- CD8⁺ T cells than in CD4⁺ CD8^- T cells in all ages analyzed. These results indicated that the age-related changes in percentages of major lymphocyte subsets as well as in phenotypes of T cells might be related to the maturation of the immune system including an increase in memory cells in cynomolgus monkeys.

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Mouse blastocysts derived from in vivo fertilization were cryopreserved by a simple vitrification method. Most of the cryopreserved blastocysts survived while demonstrating a normal morphology after warming (88.1%). The rate of cryopreserved blastocysts which developed to term as normal young was 56.8%, and chimeric mice were also produced from cryopreserved blastocysts injected with ES cells. As a result, 3.4% of the injected embryos developed to term as germ line chimeric mice.

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The characteristics of airway responsiveness to acetylcholine (ACh) in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs were clarified in vivo and in vitro. We measured the change in ventilatory mechanics in response to ACh inhalation by means of the bodyplethysmograph and the contractile responses of isolated trachea to ACh and carbachol (CCh). Further, muscarinic receptor subtypes involved these responses were identified. The basal values for ventilatory mechanics in BHS were not significantly different from those in BHR. Respiratory resistance to ACh was progressively increased in a time- and dose-dependent manner in BHS. The contractile responses of tracheal smooth muscle to ACh in BHS were significantly greater than those in BHR, but CCh-induced responses in BHS and BHR were similar. ACh- and CCh-induced contractions were mediated via M₃ receptors. These results suggested that the falling-down of BHS in response to ACh inhalation was caused by the strong constriction of the airway and the reduction in ventilation. Moreover, the airway hyperresponsiveness to ACh in BHS might be partly dependent on the change in acetylcholinesterase activity.

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A lectin histochemical study was carried out on the dorsal skin of Wistar-derived hypotrichotic WBN/Ila-Ht rats (HtRs) and Wistar rats (WRs) at 3, 7 and 24 weeks of age to clarify the lectinhistochemical characteristics of the skin during their development. The lectins examined were Concanavalia ensiformis (Con A), Dolichos biflorus agglutinin (DBA), Griffonia simpliciolia (GS-I), Helix pomatia agglutinin (HPA), Arachis hypogaea (PNA), Glycine maximus agglutinin (SBA), Ulex europeus agglutinin (UEA-I) and Triticum vulgaris agglutinin (WGA). None of the nucleated cell layers of the epidermis had DBA-binding sites, but they were all stained intensely with HPA and weakly with Con A irrespective of the strain and age of the rats. As to the other 5 lectins, the intensity of binding activity was generally weaker in HtRs than in WRs and at 3 weeks of age than at 7 or 24 weeks of age, respectively. Among them, UEA-I mainly bound to the spinous cell layer but not to the basal cell layer, suggesting that α-L-fucose would be expressed on the cell surface according to the differentiation of keratinocytes. In addition, GS-I, HPA and UEA-I bound to the hair follicle epithelium and many lectins stained sebaceous gland epithelial cells. In conclusion, except for the binding intensity of some lectins, there were no specific differences between HtRs and WRs in the lectinhistochemical characteristics of the dorsal skin epidermis. The present data on the rat skin would be useful from the viewpoint of comparative lectinhistochemistry.

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To determine the amount of endogenous amino acids in budgerigars (sekiseiinko, Melopsittacus undulatus), as the first step of evaluating amino acid requirements, three experiments were conducted. In Experiments 1 and 2, transit time of the feeds through the digestive tract in budgerigars was studied. The birds were given free access to a corn-based diet containing 50% barium sulfate in Experiment 1, and Japanese millets (hie, Echinochloa utilis) with 0.5 ml of 50% barium sulfate solution in Experiment 2. At intervals of 0.5 to 2 hr, roentgenography was conducted to identify the position of the barium sulfate in the digestive tract. The results showed that the transit time of pellets and millets in the digestive tract was within 24 and 27 hr, respectively. In Experiment 3, to determine the amount of endogenous amino acids in budgerigars, the excreta were collected for 24 hr, from 27 to 51 hr after fasting. The excreta were hydrolyzed with 6 N hydrochloric acid at 110°C for 22 hr for the determination of maino acids by HPLC. The endogenous Ala, Arg, Leu, Lys, Phe and Val were estimated to be 23.9, 36.8, 18.5, 20.3, 15.3 and 18.9 μg/day/BW^0.75, respectively, which were higher than those in adult roosters.

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In this study, we examined serum anti-ovalbumin (OVA) IgE and IgG antibodies in laboratory-reared squirrel monkeys (Saimiri sciureus), that were fed a boiled quail egg everyday. We found that 36 of 95 monkeys (38%) possessed specific IgE and 44% (42/95) had specific IgG against OVA. These antibody titers seemed to increase with age. There was, however, no apparent correlation between the anti-OVA IgE and IgG antibody titers.

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A serological investigation by means of an enzyme immuno assay test for herpes B virus (cercopithecine herpesvirus 1) was performed on 961 sera of healthy nonhuman primates reared in laboratory animal facilities which belong to the Association of Laboratory Animal Facilities of the National University of Japan. An antibody prevalence of 40% (384/961) was demonstrated. The antibody titer was shown to be higher among macaques (60% of cynomolgus monkeys, 53% of rhesus monkeys, and 34% of Japanese monkeys) than among non-macaque species (21%). These data indicate that nonhuman primates reared in animal facilities may present an occupational health problem and a potential zoonotic biohazard as demonstrated in limited cases in the United States.

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We attempted to rear and breed Plateau pikas (Ochotona daurica) captured in Mongolia in 1994 and 1995. In rearing indoors, though coitus was observed, none of the females became pregnant. In rearing outdoors, males began to make high-pitched, continuous cries and the first offspring (3 newborns) were obtained in June, 1997. The body weight averaged 8.4 g at birth, and 75.8 g at 4 weeks of age. They were weaned at 4 weeks of age. In August the testes, which had descended into the scrotum, atrophied. In September, the atrophied testes returned to the abdominal cavity. These results indicate that breeding of plateau pikas is possible when they are reared outdoors, and they have a specific reproductive season.

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"Orphan" parvovirus (OPV) infection in laboratory mice and rats was serologically surveyed for 465 mouse sera and 271 rat sera collected from 1986 to 1987 and from 1993 to 1996 in Japan. The results suggest that parvovirus infection is rare in mice but common in rats (positive rate: 13-22%) and that most putative viruses were OPVs. OPV is therefore considered to already have been harbored for at least ten years in Japan.

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The authors investigated changes in the location and number of osteoclasts and their precursors during the development of articular lesions in type II collagen-induced arthritis in mice using tartrate-resistant acid phosphatase (TRAP) staining. The limb joints were examined at 6 to 15 weeks after the second immunization. The number of TRAP-positive cells increased as the articular lesions progressed. TRAP-positive macrophage-like cells were found in the hyperplastic synovial tissue and bone marrow stroma in the early stage. In the advanced stage, in addition to many TRAP-positive osteoclasts on the bone surface, TRAP-positive macrophage-like cells were observed in the pannus apart from the bone surface in the pannus-joint junctions. The above mentioned TRAP-positive macrophage-like cells are considered to be osteoclast precursors.

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