EXPERIMENTAL ANIMALS
Online ISSN : 1884-4170
Print ISSN : 0007-5124
ISSN-L : 0007-5124
Volume 16, Issue 1
Displaying 1-3 of 3 articles from this issue
  • I. BIOMETRIC STUDY OF PROPORTIONAL PHYSICAL GROWTH
    Teisuke IBARAKI, Shin-ichi NOMURA
    1967 Volume 16 Issue 1 Pages 1-11
    Published: January 30, 1967
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    One hundred and fifty-five off springs of ICR-JCL mice, composed of 74 females and 84 males from 8 fathers and 16 mothers were subjected to study the growth of various parts of the body from the 3 rd to the 71st day after birth.
    About 10 mice each, picked up at random from total members of sixteen litters were grouped at weekly interval corresponding to growth. The animals were killed by ether and placed ventrally on a board. The lengths of head, trunk, and tail, as well as body weight were measured. This procedure was repeated three times, ranged over a year and aimed at elimination of possible influence of different season of the year to growth. The mean value and standard deviation of each stage of growth were calculated.
    Using the average values of the different parts of the body obtained, the absolute growth of each part and the relative growth between two different parts of the body were studied. The results were summarized as follows.:
    1) The length of the head reached its maximum within 6 to 7 weeks after birth, presenting the most rapid growth among the subjected parts. Such growth of the head might be of neural type, in contrast to the other subjected parts showing lymphoid type of growth.
    2) The increase of tail length was far more prominent when compared with that of the trunk or head. Although the tail was shorter than the trunk one week after birth, the rate of the tail to the trunk increased rapidly during the second week. Near the complete maturation at 9 to 10 weeks after birth, the lengths were approximately 1.5, 2.5 and 5 times respectively in the head, trunk and tail, as compared with that of each parts at one week after birth.
    3) From the change of external appearance of various parts of the body, the developmental stage in mice was presumed to be divided into two periods, the first covering 3 weeks after birth and the second from 4 to 7 weeks. The maturation in outward appearance was completed at the 7 th week of life, whereas the body weight reached its maximum 8 to 9 weeks after birth.
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  • Yoshio TAKAGAKI, Masaharu NAIKI, Masako ITO, Goro NOGUCHI, Kôsak ...
    1967 Volume 16 Issue 1 Pages 12-19
    Published: January 30, 1967
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    Cortisone injection tests were made to check infections due to Corynebacterium and Tyzzer's organism among mouse breeding colonies and the following results were obtained.
    A single injection of 2.5 to 5 mg cortisone was effective to check the both infections and the symptoms in resulting fatal disease or the lesions in killed animals after cortisone injection were perfectly analogous to those observed in the natural infections. A part of cortisone-injected mice died of the infection within 2 weeks after injection, although most of infected animals were detected when killed at the end of the observation. The incidence of the both infections was much higher in cortisone-treated young animals than in non-treated ones or in retired breeder animals from the same breeding colony. Since maintainance for a certain period in the laboratory, where contamination was possible, seemed to render animals resistant to cortisone injection test, it might be desirable to make the test on arrival at the laboratory.
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  • III Changes of Viable Count of Fecal Bacteri with Age
    Kazuyoshi MAEJIMA, Fusako MAEJIMA, Yoshio TAJIMA, Minoru OKUGI
    1967 Volume 16 Issue 1 Pages 20-25
    Published: January 30, 1967
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    Changes of fecal bacterial flora with age were examined in mice. In general, no organism was detected in feces of the 1-day-old mice, while a small number of bacteria were recoverd in a few mice aged 3 days. Enteric bacteria reached a constant population around 3 weeks after birth (104-6/g), showing a maximum count around 1 week after birth (109/g) . A constant population of streptococci or staphylococci was established around 1 week after birth (104-6/g) . The population of lactobacilli or bacteroides reached the maximum level in mice aged 2 to 3 weeks (109/g) . Spores of aerobic rods were first recovered in 3-week-old mice (103/g), and considered as transient organisms fed with diet. Although a small number of yeasts were detected in a few mice within 2 weeks after birth, a constant level of the population was established 3 weeks after birth (106-7/g) . Bifidus and clostridia were, detected in a few mice. At present, there was no evidence on the difference among mouse strains in the development of fecal flora.
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