Heat resistance tests for the saprophyte, Cladosporium, isolated from laboratory animal facilities were carried out. In testing the effects of moderate and high temperature conditions, C. sphaerospermum (C.s) and C. cladosporioides (C.c) were found to grow on media in temperatures less than 32°C, but did not in temperature of 35°C and over. The colony diameter of Cladosporium became smalleras temperature increased. The death time of C.s treated with moist heat was within 12 min at 48°C and that of C.c was within 26 min at 43°C. Both Cladosporium species could not survive for more than 1 min at 55°C. On the other hand, Cladosporium treated with dry heat could not survive more than 69-12 min (C.s) and 39-9.5 min (C.c) at 70-100°C. From these results, it can be seen that Cladosporium was definitely sensitive to heat treatment, and the authors assume that heat is a means of prevention in laboratory animal facilities.

View full abstract

Effects of the administration of heat treated cells of intestinal lactic acid bacteria were examined in rats fed a deoxycholic acid (DCA) diet. Male Wistar rats were given a 0.25% DCA diet with or without the heat treated cells of Enterococcus faecalis AD 1001 (EFH-1) or Lactobacillus reuteri AD 0002 (LRH-2) for 4 weeks. Abnormal increases in serum GOT, GPT, UN and lipoproteins were observed in the rats fed the DCA diet. Furthermore, severe lesions in the kidney as well as in the liver were found in these rats. On the contrary, the increases in serum GOT, UN, VLDL and LDL were significantly suppressed, and markedly fewer lesions in the liver and the kidney were observed in the rats fed the DCA diet plus EFH-1 or LRH-2.

View full abstract

Urethane-anesthetized male rats have been used for the analysis of prolactin (PRL) -releasing substances on PRL secretion. However, there are only a few reports investigating the effect of urethane anesthesia on PRL secretion in female rats. In this study, we intended to examine the effects of urethane anesthesia on PRL secretion during proestrus in the rat. Proestrus PRL surge was completely blocked when urethane was administered to rats prior to the critical period of proestrus both at doses of 1.0 g/kg and 1.5 g/kg. Additionally, urethane, at a dose of 1.5 g/kg, was also effective in blocking spontaneous ovulation. An experiment examining pituitary PRL concentration at 1800 h confirmed that urethane (1.0g/kg) anesthesia prevents the PRL surge from the pituitary. Similarly, urethane anesthesia blocked the LH surge from the pituitary, but LH levels in the urethanetreated group were higher than those in the pentobarbital-treated group.

View full abstract

Nonlinear growth models having a three-or four-parameter family were applied to individual body weight data of 5 male African green monkeys for estimating their growth patterns. Body weight was measured from birth to six years of ageand 58to 114 data items per monkey were collected. The average body weight atbirth was 360g with the standard deviation off 25g, 4.54±0.29kg at five years of age, and 4.50 ±0.12kg at six years of age at which point body weight was judged to have reached a plateau. Five growth models (Gompertz, Logistic, Richards, Bertalanffy and Brody) were applied to the growth data in this study. As a result, two (Gompertz and Logistic) of the five models were found applicable to all data from the five monkeys. However, the coefficient of determination (R²) obtained by application of the two models were not so large (0.919±0.05 in Gompertz, 0.889 ± 0.01 in Logistic) . Therefore the data were divided into two groups according to monkey age : the first group being from monkeys between birth and 2 years 10 months of age and the second group was from monkeys older than 2 years 10 months of age. The Gompertz model fitted best the data of the first group in four of the five animals (R²=0.982±0.011) . The age at the inflexion point in the Gompertz model nearly corresponded to the age of weaning. The Logistic model was most suitable for the date of the second group in all five animals (R²=0.955±0.038) . The age at inflexion point of the Logistic equation corresponded approximately with sexual maturation judged on the bases of changes in skin color of the face and scrotum, changes in testicular size and those in concentration of serum testosterone.

View full abstract

The purpose of this paper was to examine the effect of chair restraint on plasma enzyme values in the rhesus monkey. Six monkeys were restrained to the monkey chair for eight hours. Creatine phosphokinase (CK) value increased significantly tnree hours after the onset of restraint and LDH value did eight ho, irc After the onset o restraint. The increase in CK, GOT and GPT values continued fnr 1 nr 2 days after the release from restraint. On the other hand, these plasma enzvme values in non-restraint monkeys showed almost no changes. These raesults indieate that it is necessary to establish a proper method for the adjustment to chair restraint in the rhesus monkey.

View full abstract

The purpose of this study was to examine the effects of repeated chair restraint on some physiological values in the rhesus monkey. Although heart rate and blood pressure increased significantly at the onset of chair restraint, these increased values gradually decreased with repetition of restraint as well as with the lapse of time after restraining. Finally, no elevation of these levels was detected after repetitions lasting eight hours per day for five days. Plasma cortisol, CK and GOT values also showed similar trends. These elevated physiological values at the onset of chair restraint seemed to be due to high sympathetic tone and muscular activity used to try to avoid the restraint. It is concluded that repeated chair restraint has an accommodative component in monkeys resulting in the return of some elevated physiological values to the normal level.

View full abstract

Heat resistance of free-spores of 78 Bacillus strains isolated from laboratory animals was examined. Spores of 41 out of 78 strains survived for 320minutes at70°C, 27 for 160 min, at 1001, only one for 20 min, at 110°C by autoclaving, and none for 5 min. at 120°C. D-values at 100°C of 9 strains determined were between 5.03 and 30.06 min. Spores of 9 strains from stock cultures were exposed to ozone gas at various conditions. Ozone resistance of spores was closely dependent upon relative humidity. D-values of the spores tested by treatment with 200 ppm ozone at 60% RH were over 200 min., especially over 1, 000 min. in 4 strains, indicating that exposure to ozone at a moderate humidity for 6 hours could not sterilize Bacillus spores. At 90% RH, however, treatment with 200 ppm ozone for 6 hr. might be effective for a routine sterilization in laboratory animal facilities.

View full abstract

To compare the incidence in the diabetic syndrome in mice reared under sterile and non-sterile conditions, both conventional and SPF DBA/2 N male mice were inoculated intraperitoneally with two doses (10⁴ TCID₅₀/0.1ml or 10⁵ TCID₅₀/0.1ml) of encephalomyocarditis (EMC) virus M variant. The incidence of diabetic symptoms was higher in mice reared under sterile conditionthan under non-sterile condition. It appeared that a difference in animal rearing conditions would affect the sensitivity to EMC virus in mice.

View full abstract

A new hair defected mutant rat was established. This mutant was covered with ragged hair since about 10 days of age, then transiently lost most of hair in the back at approximately 5 weeks of age and was re - covered with ragged hair thereafter. Thickened eyerids occurred since about 3 weeks of age. Histological examination revealed enlarged sebaceous glands with greater number of sebaceous cells in the back skin. The oil stained skin samples showed normal sebaceous transformation and pilosebaceous canal. Genetical analysis showed that the ragged hair character was a single recessive trait and indicated that this single recessive gene was not linked with the coat color genes, non-agouti (a), albino (c) and hooded (h) . From the present data and previous reports, we recomended this single recessive gene is a new rexoid mutation thereby we termed this gene “Ragged (rg) ”.

View full abstract

The population of T-cell subsets, the blastogenic responses of lymphocytes in blood and spleen and splenic NK cell activity were examined in mice transferred from 221C to 12t or 32t environments. The percentage of Thy-1.2 positive cells and Lyt-1.2 positive cells in the spleen decreased after the transfer. However the percentage of Lyt-2.2 positive cells in the spleen was not affected. Thy-1.2 and Lyt-1.2 positive cells in the blood also decreased. The percentage of Lyt-2.2 positive cells in the blood was not affected in mice exposed to 12°C. However, Lyt-2.2 positive cells in the blood decreased on day 1 but increased on day 3 in mice exposed to 32°C. Blastogenic responses of spleen lymphocytes to concanabavalin A (Con A) and pokeweed mitogen (PWM) were suppressed in transferred mice, but responses to lypopolysaccharide (LPS) and phytohemagglutinin-P (PHA-P) were not affected in any group. Blastogenic responses of blood lymphocytes to Con A, PHA-P, and PWM tended to be weaker in transferred mice than in mice kept in the 22°C environment. In particular the response to PWM in mice exposed to 12°C was less than 8 % of that in the 22°C mice. Splenic NK cell activity decreased in transferred mice, but was not suppressed as much as in mice administered 5mg of cortisone acetate. These data show that the number of helper T cells decreases and that the blastogenic responses of T cells and NK cell activity are suppressed in mice transferred from 22°C to 12°C or 32°C environment. It thus seems plausible that wide variations in environmental temperature may encourage infectious diseases and manifestations of latent infections in mice.

View full abstract

Embryo transfer was attempted in order to control disease in rabbits. Embryos were collected by flushing of the oviducts of donor rabbits on Day 2 of gestation, into small tubes containing the medium, transported within the body warmth of the person carrying the tubes and transferred into the oviducts of SPF pseudopregnant recipients. The time between embryo collection and transfer was 7-8 hours. Ten of 56 embryos derived from Bordetella bronchiseptica infected animals developed into newborns. As a result of bacteriological examination of intranasal exudate in six weanlings, no pathogens were detected. We suggest that embryo transfer is an effective and simple alternative to caesarian operation in Bordetella bronchiseptica infected rabbits.

View full abstract

The quantity of histamine and the number of mast cells in the skin of the pika were measured and compared with rabbits, guinea pigs and rats. The ranking of regional histamine levels in the skin of the pika was : perianal region>abdomen> interscapular region=back>lumbus>head>auricle, and the average value of the 7 regions was 22.6μg/g. The level of histamine in the 6 regions, except the auricle, was 2 - 5 timesthat of rabbits and guinea pigs. In the auricle of each of the 4 kinds of animal (pika, rabbit, guinea pig and rat), the levels were almost identical. With respect to histamine levels, those in the pika resembled those in rats. The number of mast cells in the skin of the pika was less than in rats, and was greater than that in rabbits and guinea pigs. The average value was 9.9/mm².

View full abstract

Hematological values of the peripheral blood in the mice transplanted with methylcholanthrene-induced fibrosarcoma were examined. Values for red blood cells and platelets reduced after tumor transplantation. Values for white blood cells increased with the percentage of neutrophils being increased significantly. Phagocytic activity of neutrophils from the tumor-bearing mice was not reduced. The cultured fluid of the tumor used in the experiments possessed strong colony stimulating activity to bone marrow cells.

View full abstract

Embryo collection from Göttingen miniature pigs and transfer to common pig recipients were performed. Embryos were collected 2 to 6 days after the onset of estrus. Two to 7 eggs including unfertilized ova were collected from a naturally ovulated donor and more eggs (7 to 15) were obtained from a superovulated donor. A total of 21 piglets were born after transfer of 33 miniature pig embryos to two common pig recipients. Among them 12 were stillbirths which seemed to have resulted from suffocation during the parturition. Such an embryo transfer technique will be utilized as an inventive method for the purposes such as international exchange of the particular strains of miniature pigs, establishment of a SPF miniature pig herd and so on.

View full abstract

The purpose of this paper is to describe some fundamental physiological data in F 1 hybrids bred from a Mexican hairless dog and beagle cross. These F 1 hybrids numbered 5 hairless dogs and 12 haired dogs. The hematological profile of these offspring was assessed via an automated cell counter and compared with those of healthy beagles. In hairless dogs, red blood cell count, hemoglobin concentration and packed cell volume tended to be higher than in beagles. White cell distribution curves in hairless dogs and beagles yielded a single peak, while in haired dogs one or two peaks were present. Red blood cell and platelet distribution curves revealed few differences among the 3 kinds of dogs.

View full abstract

The bile duct system of normal rats was examined histochemically. Although the apical surface of biliary and glandular epithelial cells was positively stained with Concanavalia ensiformis (Con A), Dolichos biflorus (DBA), Glycine max (SBA), Ulex europeus-I (UEA-I) and Triticumvulgaris (WGA), the cytoplasm did not apparently react with any lectins. Therefore these cells might not play an important role in an active secretion of mucin. On the other hand, the cytoplasm of goblet cells was positively stained with periodic acid-Schiff, high iron diamine, Con A, DBA, Griffonia simplicifolia- II (GS-II), SBA, UEA- I, and WGA. This suggests that mucin secreted from the goblet cells may be acid one with sulfonic terminals.

View full abstract

The median liver lesion producing doses of peroral inoculation with the spores of Tyzzer's organism RJ strain were 10^4.3 in rats and 10^2.7 in rats receiving prednisolone treatment for the provocation of Tyzzer's disease. In contrast to rats, liver lesions were detected in few mice inoculated perorally with 10⁷ spores. In mice inoculated perorally with 10⁷ spores, excretion of infective spores in the feces was detected only on day 1 postinoculation. On the other hand, no difference in suceptibility between rats and mice was detected upon intravenous inoculation with vegetative cells of the RJ strain. These results suggest that germination of the spores in the intestinal tract causes the difference in the susceptibility in rats and mice.

View full abstract