In 1979, some pairs of voles (Microtus arvalisPallas) were introduced to our laboratory from Hungary. Thereafter, they were successfully bred and increased in number, as experimental small animals for herbivorous domestic animals. They have been raised in a room and fed with pelleted feed for herbivores and chopped hay-cubes. We can change the high-fiber-containing rations from the chopped hay-cube to the alfalfa pellet that is widely available in laboratories. Regarding the breeding characteristics of the voles, the average litter size was 5.44±1.64, and the age at the first birth was 55.4±10.7 days. Some voles with white coats were found during the breeding process in our laboratory. Hematochemical characteristics of the voles were determined and the following characteristics were noted. 1. Red blood cell counts of the voles were higher than those of other experimental animals (rat, mouse) . 2. White blood cell counts of the voles were lower than those of the other animals. 3. The electrophoretic patterns of serum protein differed markedly from those of other experimental animals. The γ-globulin concentrations of the voles were very low, and A/G ratios were high. 4. Blood glucose concentrations of the voles were lower than those of the other mono-gastric experimental animals. 5. Activities of serum enzymes (GOT, GPT, ALP) were higher than those of other experimental animals (rat, mouse, cow) .

View full abstract

To produce transgenic mice carrying human β-globin genes, we introduced the following two constructs of the genes to male pronuclei of fertilized mouse eggs: 4.4 kb P_stI/P_stI sequences of the human β-globin gene (experiment 1) and the human β-globin gene cluster (cosHG 28) conaining G γ, A γ, δ and, β-globin genes and cosmid vector pJB8 (37.5 kb, experiment 2) . In experiment 1, 25 mice were born, and four (one female and three males) carrying the injected gene sequences were identified. One of these mice carried the entire sequence of the human β-globin gene but three others appeared to carry only a part of the entire sequence. The mouse with the entire sequence showed a slight increase in the minor component of the mouse β-globin chain in the same position as the human β-globin chain. In experiment 2, 61 mice were born, and nine (three females and six males) carried the sequences of the injected gene. However, from DNA analysis, no appropriate sequences present within the A γ-or β-globin gene were identified in any of the founder mice. In this case, DNA fragments of the gene cluster that were digested in the mouse nucleus after microinjection of the gene might be integrated into host DNA.

View full abstract

The pathological examination of the rabbit knee joint with antigen-induced arthritis produced by heat-killedStreptococcus faecalis (Str. faes.) as antigen was carried out. Macroscopically, there were findings of acute inflammation about five hours after the injection. Histopathologically, very remarkable acute exudative inflammation was seen 48 hours later. This supponted the picture of Arthus reaction. The Arthus reaction disappeared with time, and this supported the view of delayed-type hypersensitivity three weeks later. After that, an obvious chronic inflammation was admitted in 10 weeks. This resembled the histopathological feature of rheumatoid arthritis (RA) when these findings are summarized. It was suggested that arthritis produced byStr. faec.progresses from an acute condition to a one with time. As mentioned above, it thought that Arthus reaction of both immediate hypersensitivity and delayed-type hypersensitivity are necessary in the occurrence of this arthritis.

View full abstract

In order to determine the optimun conditions suitable for a number of trials and the intensity of unconditioned stimulant (US) in the two-way shuttle-box avoidance test in Sprague-Dawley strain rats, which are used most frequently in reproduction studies, conditioned avoidance response was observed under various conditions for 30 and 60 trials and the low and high US levels. Investigation was also conducted in Wistar rats under a high US level with 30 and 60 trials. Latency time of the escape response in Sprague-Dawley rats was shortened with increasing trials. Body weight gains of both strains of rats in the high US level with the 60-trial group decreased during the observation period. These findings suggest that the high US level with the 60-trial group is not suitable for the two-way shuttle-box avoidance test. The rate and latency time of the avoidance response were lower in Wistar rats than in Sprague-Dawley rats, although those of the escape response were higher. Significant changes in the following were observed, mainly from first to third sessions: the avoidance rate of all groups in strains of rats, escape rate of 60-trial group in Sprague-Dawley rats, avoidance and escape latency time of the 60-trial groups in both strains of rats and escape latency time of the 30-trial group in Sprague-Dawley strain rats.

View full abstract

Coprophagy was observed in germf ree (GF) ICR mice of both sexes, and the results were compared with those of conventional mice. Frequency of coprophagy per animal per day in GF mice was 5.1 in males and 5.8 in females. In conventional (CV) mice, the frequencies were 6.2 in males and 5.3 in females (data fromZoological Science2: 249-255, 1985), with no significant differences compared with GF mice. Coprophagy in CV mice was frequently observed during 6-8 hr after lighting, whereas such close time relationships tended to weaken in GF animals. In a comparison of levels of constituents per unit weight between feces and diet, fecal crude protein and crude fat exhibited lower values than those in the diet. Levels of fecal crude ash and crude fiber were higher than those in the diet, and nitrogen-free extract was almost equal to that in the diet. No essential difference in these tendencies was found compared with CV mice. Levels of fecal vitamin B₁, B₂, B₁₂ and folic acid were lower than those in the diet. In CV mice, except for vitamin B₁, these vitamins exhibited either almost equal or much higher levels compared with those in the diet (data fromExperimental Animals35: 381-386, 1986) . From the fact that coprophagy was observed in GF mice, it is suggested that the behavior is inherent in the mouse.

View full abstract

In two natural outbreaks ofS. typhimuriuminfection in guinea pigs, frequent isolations of the organism from the conjunctiva and cervical lymph nodes and high incidences of the conjunctivitis and abscess formation in the cervical lymph nodes were shown, suggesting more importance of the conjunctiva as infection route than oral route. These features in salmonellosis of guinea pigs were tried to reproduce in experimental infections by conjunctival and oral inoculations of 10²and 10⁶cells of 4 different strains ofS. typhimuriumand also by contact infection simulating natural conditions. As the results, it was demonstrated that guinea pigs were more susceptible to the conjunctival infection than the oral infection, because higher infection rates and more frequent incidence of abscess formation in the cervical lymph nodes as well as conjunctivitis were produced by the conjunctival inoculation than the oral inoculation of the organism. Main localization sites of the organism were the cervical lymph nodes, conjunctiva and upper respiratory tract in conjunctivally inoculated guinea pigs but more widely distributed in orally infected ones. These findings were common in animals infected with 4 different strains ofS. typhimuriumand also in contact infection. Thus the conjunctiva was regarded as an important route ofS. typhimuriumin guinea pigs.

View full abstract

A method of nonsurgical embryo collection in the Shiba goat, a native Japanese miniature goat breeding nonseasonally, was developed. The apparatus used for flushing the uterus was made on the model of the two-way catheter for cows. Embryo collection was performed on days 5 to 7 in 37 females superovulated with PMSG and hCG and resulted in successful recovery of 69 embryos in 19 females (51.40) . The average number of embryos collected from each successful female was 3.6. The recovery rate of embryos calculated on the basis of the number of embryos recovered and corpora lutea observed by culdoscopy in 15 successful females was 89.50. This nonsurgical method seem to be efficient enough for collecting morulae and blastocysts in Shiba goats.

View full abstract

Serum constituents and liver of the wild male suncus as well as of those bred and fed in our laboratory were examined serologically and histologically. The following results were obtained: (1) The serum glutamic-oxaloacetic transaminase, gamma-glutamyl transaminase, inorganic phosphate, blood urea nitrogen, creatinine, uric acid, and zinc turbidity test levels of wild suncus were higher than those of 4 and 8 week old fed suncus. (2) The total cholesterol level of wild suncus was lower than those of 4 and 8 week old fed suncus. (3) In wild suncus, the total bilirubin and direct bilirubin levels were higher, and the Ca and albumin levels were lower than those of 4 week old fed suncus. However, no significant differences were observed between the wild and the 8 week old fed suncus. (4) Although the alkaline phosphatese and thymol turbidity test levels of wild suncus were larger than those of 8 week old fed suncus, no significant differences were observed between the wild and the 4 week old fed suncus. (5) The histological study revealed the presence of fatty droplets in only 2 of the 67 wild suncus examined while fatty droplets (grade +) were observed in almost all the fed suncus. In one case of the wild suncus, moderate round cell infiltration in interlobular connective tissue was found.

View full abstract

The testicular development in gerbils was studied over 16-week periods starting from birth. Testicular weight and seminiferous tubule diameter increased considerably between 1 and 11 weeks of age. At 16 weeks the testicular weight was about 540 mg. Spermatogenesis commenced at about 2 weeks when mitoses first appeared in spermatogonia. Spermatozoa appeared in a few of the seminif erous tubules by 7 weeks and consistently so in all of the tubules at 10 weeks. Epididymal spermatozoa appeared first in the cauda epididymis at 10 weeks and were consistently present at 12 weeks. Formation of mature Leydig cells with a grouped perivascular arrangement appeared by 3 weeks and continuously so thereafter. From these results, it is evident that the male Mongolian gerbil is almost sexually matured by 10 to 12 weeks of age.

View full abstract

Linkage tests on the faded gene were carried out with some coat color and biochemical markers, It was shown that the faded locus was not closely linked to the following loci: Idh-1 (chromosome 1), a (2), Car-2 (3), Mup-1 (4), Pgm-1 (5), Hbb (7), Gpi-1 (7), Es-1 (8), Trf (9), Es-3 (11), s (14), Sod-1 (16) andCe-2 (17) . The mutant locus showed linkage withGgcon chromosome 6.

View full abstract

A discontinuous sucrose gradient was employed in the separation of mouse blood platelets using a modified Booyse method. The platelets of male CD-1 mice aged 8 to 12 weeks were divided into five distinct populations (A, B, C, D & E) . Distribution of light to heavy platelets patterns in 10 normal CD-1 mice was demonstrable at; A (S.G. 1.188), as 14.8±5.6%; B (S.G. 1.199), 44.0±4.6%; C (S.G. 1.207), 24.1±3.4 %; D (S.G. 1.214), 13.0±3.6%; and E (S.G. 1.221), 4.0±1.5%.

View full abstract

Recently a Mongolian gerbil has become a useful laboratory animal, while little ofthe basic data are known about the breeding and growth of this laboratory rodent.In our animal center, an inbred strain of the seizure prone gerbil has been producedand kept these ten years. The data on the breeding and growth of the animal wereobtained and described as following in the present paper. 1. The mean life span was26±14month old for males and 27±13 month old for females.2. The mean bodyweight of the Mongolian gerbils at 16 weeks of age was 72±5.6g for males and 62±7.3gfor females.3. The mean litter size at birth was 4.8±1.7 head. (range; 1-9) 4.More newborn pups were born in the warm seasons (March-October) than the coldseasons (November-February) . 5. The mean rate of weaning was 80.2%. 6.Theman litter size was relatively constant in each generation.

View full abstract

Some morphological characteristics of the Mexican hairless dog and their inheritance were investigated. The dogs examined were hairless and had defective teeth. From the results of mating experiments, an autosomal dominant semi-lethal gene was considered to be responsible for the hairlessness accompanied by defective teeth in the dog. The possible usefulness of the dog was also discussed.

View full abstract

The male's sexual behavior paired with estrogen-progesterone primed induced ovariectomized receptive females was compared with natural proestrous females. The former showed longer ejaculation latency and more intromissions to the first ejaculation than the latter.

View full abstract