The Kitasato archives of experimental medicine最新文献

The influence of phagocytic activity on the early stage defence mechanisms in zinc deficient mice was studied using active oxygen production as a parameter and the results obtained were as follows: 1. The body weight of the zinc deficient mice was decreased significantly compared with that of the normal mice. 2. Zinc levels in the liver and blood of the zinc deficient group showed low comparing with the zinc adequate and the control groups (P less than 0.01). 3. The numbers of intraperitoneal (i.p.) cells, which play a leading role in early stage defense mechanisms, showed lower levels in the zinc deficient mice than that of the normal mice. 4. Phagocytic activity was measured as active oxygen production and this activity was found to be impaired in zinc deficient mice. 5. After the typing of i.p. cells and blood cells, it was proved that lymphocyte (lym.) was the main cell (68.5% and 73.8%) in i.p. cells and blood cells of the zinc deficient mice. The control group (non-treated mice) and the zinc adequate group showed a similar pattern of these zinc deficient mice.

Mycobacterium leprae is an obligate intracellular parasite and grows within mononuclear phagocytes. When murine macrophages derived from the peritoneal cavities of CBA mice were infected in vitro with M. leprae (Thai-53 strain), intracellular multiplication was observed three weeks after infection. On the other hand, there was no increase in the number of heat-killed M. leprae at the same times after infection. Morphological studies showed that the growth rate of the bacteria increased by about 20-30% in medium supplemented with cycloheximide. With the addition of cycloheximide to the culture medium, metabolic activity of macrophages was decreased but infected cells were maintained in good condition and seldom floated off from the culture flask.

The ovary and eggs of adult tick Haemaphysalis longicornis (H. longicornis) infected with Babesia ovata (B. ovata), were examined at regular intervals of time. As a result kinetes could be detected in the ovary for the first time 6 days after engorgement. The kinetics could be classified into three types on the basis of their morphological characteristics. On the 2nd day after oviposition, round-formed protozoa were found in the ooplasm of the egg. In 5 days after oviposition, these round-formed bodies were transformed into club-forms. On the 9th day after oviposition, the kinetes were observed in the ooplasm. Morphologically, it seemed possible that B. ovata is transmitted by eggs of the tick, H. longicornis.

To elucidate the current status of foal diseases in Japan, clinico-pathological analysis was conducted on 237 foal autopsy cases. As a result, bacterial infection was identified as an important cause of foal death. Most of the bacteria isolated from these cases were ubiquitous, opportunistic, environmental organisms, known to be non-pathogenic to mature animals. Most of cases with bacterial infection were diagnosed as having hypogammaglobulinemia, i.e., failure of passive transfer. In addition, the mean weight of thymuses in foals affected by bacterial infection tended to be lower than that of foals without infection. These findings suggest that the common cause of foal diseases were mainly due to the opportunistic bacterial infections associated with the weakened immune function, serving as precursor to or promotor of infection.

The quality of 14 lots of acellular pertussis-diphtheria-tetanus (AC-PDT) vaccines manufactured by the Kitasato Institute during the period 1987-1990 were investigated. The geometric means of HSU, LPU, and BWDU were 0.078, 0.257, and 7.33 per ml respectively. The potency was higher than 14 IU per ml. These results indicated the consistency of the Kitasato AC-PDT vaccines. The antibody response to the AC-PDT vaccines was measured in primary and secondary vaccinated mice by ELISA. IgG antibody response to FHA and PT was obtained in all immunized mice (P less than 0.001) after the primary injection. In contrast, IgG antibody response to fimbriae 2 showed a significant titer rise (P less than 0.001) after the booster injection. The results indicated that the Kitasato AC-P vaccines consisted of protein, PT and FHA as the major antigens, and a little agglutinogen as the minor antigen.

Microelectrode and stereotaxic technique were used to record extracellular potentials of the neuron in posterior group of thalamic nuclei (PO). To study the action of some neural structures in the brain, we also applied the method of conditioning-testing stimulation. We found not only somatic nociceptive but visceronociceptive neurons existed in PO. The features of the unit response (latency, discharges and its noxious properties) were studied. Stimulation of S1, cingulate gyrus, caudate nucleus, accumbens, amygdala, habenula, VPL, PAG and substantia nigra caused inhibition of nociceptive neurons in PO. Owing to emerge and recover, the inhibition can be divided into three phases: prompt, continued and delayed. All these inhibitions except VPL, Cad and SN (no observation), were reversed by Naloxone. Both stimulation of somatic peripheral nerve fibers and electroacupuncture of Sanli (S36) on the hind leg of the cat produce suppression of nociceptive neuron in PO. The mechanism of inhibition resulted from above neural structures of the brain was also discussed.