Twenty-six out of fifty pregnant rats died on days 18-20 of gestation at 33°C environment. The death generally occurred in the dark period around 1-5 a. m. Shortly prior to the death, very high body temperature of 42.0-43.7°C were recorded and the blood pressure was undetectably low. In autopsy, the finding in the main was the congestion in lungs and liver. In temporal changes of body temperature and heart rate, influences of hot environment were observed, but there was no significant difference between dead pregnant group and delivered pregnant group at 33°C environment. At 23°C, the blood pressure of pregnant rats starting at about 140 mmHg level, rearched 160-168 mmHg on day 12 of gestation and maintained the level to day 16. On day 18, the pressure returned to 140-145 mmHg and unchanged to term. At 33°C, significant differences were obviously observed between dead group and delivered group in temporal changes of blood pressure. The blood pressure of rats delivered sharply increased to 170 mmHg or more in the middle stage of pregnancy and decreased to about 140 mmHg in the final stage. However, these of dead group increased to 160 mmHg or less in the middle stage of pregnancy, and maintained the level until the final stage.

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An experiment was conducted in 76 mice (3 to 9 weeks of age) to investigate the characteristics in growth of major skeletal bones and their sexual differences. The length of ulna, radius, femur and tibia attained their maximum growth rate at earlier age, and showed no sexual difference in their growth patterns. Scapula length and width, humerus length and os coxae width reached the maximum growth rate at a later age than the forearm and shank, and showed no sexual difference in their growth, although those bones presented larger adult sizes for male than female. The length of vertebrae showed significant sexual differences in their growth patterns and adult sizes, except for lumber vertebrae. A significant sex difference in body weight caused the sexual differences in relative growth of bones to body weight. According to their relative growth to the length of humerus, the skeletal bones could be well grouped into three categories. A significant sexual difference was seen in the relative growth of scapula length. In general, it seemed that the bones growing in a vertical direction grew earlier than the bones growing in a horizontal direction, especially those of the forearm and shank. The results obtained in mice were in good agreement with the findings in pigs.

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The nutritional state of animals removed from as much antigenic stimuli as possible-germ-free mice on an antigen-free liquid diet-was compared with that of conventional mice through assessment of their protein metabolism. Both the germ-free and conventional mice reared on the antigen-free liquid diet for 7 weeks exhibited relatively stable body weight throughout the experimental period. Although the nitrogen retention rate was generally higher for the conventional mice, even in the germ-free mice with the exception of one observation in a male, positive nitrogen retention rates were observed, and this suggests nutritional adequacy of the diet. The amount of protein-nitrogen excreted in the feces due to the physiological processes, such as the digestive tract cell turnover, digestive juice secretions, etc, (4.2-5.3mg/mouse/week), and the amount that was influenced by the presence of intestinal bacteria and due to bacterial protein per se (2.3-4.4mg/mouse/week) could be estimated through the comparison of the fecal protein values obtained from germ-free and conventional mice reared on the antigen-free liquid diet.

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Mice were injected with three kinds of interferon, i. e., mouse, human leucocyte and human fibroblast interferon, and the kinetics of their clearance from the blood was compared. After intravenous injection, mouse interferon was cleared very rapidly with an initial half life of two to three minutes, while both types of human interferon were cleared rather slowly with a corresponding value of about 20 minutes. When mouse interferon was injected intramuscularly or intraperitoneally, only very low levels of interferon activity were detected in the serum, and the recovery did not exceed 1 % at any time. In contrast, both types of human interferon gave appreciable levels of activity in the serum upon injection by the same routes, and the levels remained stable during the observation period. The recovery of human interferon in the blood was about 10-fold that of mouse interferon. Mouse interferon was not inactivated in vitro by incubation with normal mouse serum. Our results suggest the validity of using homologous interferon for studies on the kinetics of interferon clearance in experimental animals.

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Genetic variants of plasma α-amylase and erythrocyte carbonic anhydrase in the musk shrew (Suncus murinus) were found by electrophoreses using cellulose acetate plates. It was demonstrated that phenotypic differences of α-amylase are controlled by two codominant alleles (Amy-1^aandAmy-1^b) at a single autosomal locus (Amy-1) . The segregation data of the carbonic anhydrase phenotypes in the progeny supported the genetic theory of two codominant alleles (Car-1^aandCar-1^b) at a single autosomal locus (Car-1) . The data suggested that there was no close linkage between the two loci, Amy-1andCar-1. TheCar-1locus was fixed with one of the two alleles in each of the four lines, i. e.Nag, Oki, Tar and Jak originating from wild animals captured in Nagasaki and Naha and Tarama Island, Okinawa, Japan, and in Jakarta, Indonesia, respectively. Oki and Tar lines still showed segregation of the two alleles at theAmy-1locus.

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An albumin-deficient and fatty strain of rats (AFR) was established from crosses between albumin-deficient rats (NAR) and fatty Zucker rats. AFRs have double homozygous mutant genes (alb/alb, fa/fa) . The AFRs are heavier than the fatty Zucker rats and they have enlarged livers and adrenal glands. In addition, AFRs show more severe hyperlipidemia than fatty Zucker rats. This strain of rats may serve as a model of human obesity and hyperlipidemia.

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Albumin (Alb) and transferrin (Tf) polymorphism in plasma ofCallithricidaewas investigated by means of starch gel electrophoresis. In 52 blood samples of three species (Saguinus mystax, S. oedi pus and S. labiatus), four Alb phenotypes (Alb 1, Alb 2, Alb 3 and Alb 2-3) and two Tf phenotypes (Tf 1 and Tf 2) were observed. No Alb variant was found-inS. oedipusandS. mystax.

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1) A comparison between forelimb amputations through the radius-ulna and the humerus was made in the adult newt, Cynops pyrrhogaster pyrrhogasterand the young toad, Xenopus laevis. Newts regenerated their forelimbs after the amputations and the new parts resembled the old in structure and function. Toads regenerated their forelimbs incompletely after the amputations. The new parts lacked joints and fingers showing a simply elongate pattern. 2) The effect of re-amputation of exposed bone on the regeneration was evaluated in the adult newt. A left forelimb was amputated through the humerus and the exposed bone which protruded from the cut surface due to the relationships of the soft tissues, was then re-amputated a few minutes later. A right forelimb of the same individual was simply amputated without re-amputation of the exposed bone. Newts regenerated both forelimbs simultaneously. The new parts resembled the old in structure and function.

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Eleven pathogens includingP. aeruginosa, Salmonellaspp., E. coliO115a, c: K (B), P. pneumotro pica, B. bronchiseptica, C. kutscheri, Tyzzer's organism, M. pulmonis, Sendai virus, MHV andSyphaciaspp. were surveyed in 217 mouse and rat breeding colonies during 1972-1981. In conventional animals, P. Pneumotro picaand / orSyphaciaspp. were detected in nearly 90 % of 89 mouse and 64 rat colonies. Sendai virus, M. pulmonis, P. aeruginosaand MHV were positive in 51.7 to 23.6 %of the colonies, and Tyzzer's organism, B. bronchisepticaand probably SDA virus were also detected in more than 10 % of the rat colonies.Salmonellaspp., E. coliO115a, c : K (B) andC. kutscheriwere found in a few colonies. In SPF animals, P. aeruginosawas isolated from about one third of 33 mouse and 31 rat colonies, andP. pneumotropicawas also positive in 3 rat colonies, Infection rates ofP. pneumotropica, M. pulmonis, Sendai virus andSyphaciaspp. were usually higher than 40 % of animals sampled from colonies contaminated with them. Accidental contaminations of SPF colonies were usually caused byP. pneumotro pica and Syphaciaspp.

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The detection rates of Sendai virus antigen in the lung and tracheal mucosa by immunof luorescence were comparable to those of virus isolation by chick embryos and seemed to be useful during the quarantine of mice and rats.

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