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Biomedical subjects

T Imamichi

Publications and source records attributed to T Imamichi.

At least 73 records · Page 4Linked to original sources

[Basic examination on the energization of experimental animal feces by methane fermentation (author's transl)].

Basic experiments of methane fermentation of livestock excreta have been reported by many investigators, yet there has been no report of experiments of methane fermentation of experimental animal feces. We considered that it would be feasible to gasiby experimental animal feces by methane fermentation. In this report, methane gas fermentation of rat feces is studied. The results are summarized as follows: 1. Methane fermentation of rat feces yielded, under the conditions described, 220-4231 of gas per kg of organic matter. 2. Decomposition ratio of BOD removal volume in organic matter was 50-60% when the fermentation condition was optimum. 3. The volume of gas from BOD removal volume in organic matter was 500-600ml/g. 4 Methane gas contents in the gas generated from the feces ranged from about 55-60%. 5. COD removal ratio was above 80%, and BOD removal ratio above 90%. From these data, the authors conclude that under the optimum conditions, described sufficient methane gas can be obtained from rat feces by methane fermentation.

Animals↗

[Variation in the number of nipples in Wistar-Imamichi rats (author's transl(].

In order to determine heritability of accessory nipples, variations in the number of nipples were investigated in 13-week old female Wistar-Imamichi rats, maintained as a closed colony in the Institute for Animal Reproduction. Most of the females examined (93.32%) had six pairs of nipples; three in the pectoral and three in the abdomino-inguinal regions. Whereas, 229 out of 3606 rats had one accessory nipple each, 9 animals had 2 accessories, and 3 females were deficient of the pectoral nipple. Most of the accessory nipples were found either in the caudal and cranial regions of the third pectoral nipples or in the regions between the second and third abdomino-inguinal nipples. The frequencies for appearance of the accessory nipples were higher in the pectoral regions than those in the abdomino-inguinal ones, and also in the left side than in the right (p < 0.01), respectively. In 208 out of 791 litters examined, 177 litters had only one sister-mate with accessory nipple, 29 litters had 2 sister-mates with accessories, and 2 litters had 3 sister-mates with accessories, respectively. The localization of accessory nipples of the sister mates within the litter was similar in most of the cases. Heritability of the appearance of accessory nipples was estimated to be 0.8074 by using the formula described by Falconer.

Animals↗

[Methods for intravenous injection and blood collection in the guinea pig via veins of the forelimb without anesthesia (author's transl)].

Methods for intravenous injection and blood collection by way of the forelimb in guinea pigs without anesthesia were investigated, with the results as follows: 1) Both the accessory cephalic and cephalic veins were found available for injection as well as for drawing blood samples. Venipuncture was accomplished with greater ease by using the accessory cephalic vein. 2) The following procedure has proven practical. (i) Clip the hair over the site. (ii) Restrain the animal to immobilize the foreleg in slight extension by grasping it at the elbow joint with the thumb and forefinger over its dorsal and ventral aspects, respectively. (iii) After disinfecting the skin surface with alcohol, perform injection using an appropriate syringe with a 27 (1/4) or 25 (1/3) gauge intravenous needle, or puncture the vein with a 23 (1/2) gauge i. v. needle to collect the blood that drips out.

Animals↗

[Studies on the development of water maze-learning ability in rats. (1) Correlation between learning ability and brain weight in growth periods (author's transl].

In order to determine the appropriate age for the water filled multiple T-maze test. Wistar-Imamichi strain rats (SPF) 3 to 10 weeks of age were given daily 3 repeat trials on three consecutive days. Learning ability was evaluated on the basis of daily decrease of errors in the water maze test. Elapsed time to reach the goal, errors and variations of these decreased with progressing trials regardless of age and sex. Comparing to the rats under 4 weeks of age, errors in the 3rd day trials became constant at lower level in rats over 5 weeks of age. These results suggest that the learning ability of rat may reach adulthood by 5 weeks of age. Brain weight also attained a plateau at 4-5 weeks of age in both sexes of rats.

Age Factors↗

[Growth and reproduction of the chinchilla-age at vaginal opening, oestrous cycle, gestation period, litter size, sex ratio, and diseases frequently encountered (author's transl)].

The paper deals with observations on growth and reproduction of the chinchilla in recent 4 years started from 1966 at this laboratory. There were large variations in age of vaginal opening (less than 71 days-308 days) with an average of 173.2+/-57.6 days in 45 females. The average length of 100 oestrus cycles in 24 females was 35.7+/-7.9 (15-62) days. The mean period of 5 gestations in 5 females was 110.4 (108-112) days. Eighty-one out of 123 litters were born between March and August during 3 years, and parturition never occurs in December. The most suitable season for reproduction of chinchillas may be from January to April, and a summer anoestrous seems to be present in August to early September as reported by Weir. The litter size ranged from 1 to 4 with a mode of 2 (46.3%) and an average of 1.90+/-0.76. More male kids were produced at birth at this laboratory, and sex ratio was 133.7 (98 females and 131 males). In 1973, 37 chinchillas gave birth to 71 kids with an average litter size of 1.92, and 59 of them were successfully weaned (1.59 per litter). Of these kids, 50 (1.35 per liter) attained 240 days of age (adulthood). Among 91 subjected to investigation for causes of death, 23 (25.3%) were dead during newborn period, and 9 and 5 adults were dead of malocclusion (9.9%) and the prolapse of rectum respectively.

Animals↗