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Biomedical subjects

H Takebe

Publications and source records attributed to H Takebe.

At least 127 records · Page 7Linked to original sources
PubMed1982

1-month subacute oral toxicity study of KB-944, a new calcium antagonist, in beagles.

Using male and female Beagles, we studied the subacute toxicity of diethyl 4-(benzothiazol-2-yl)benzylphosphonate (KB-944) administered orally and the following results were obtained. No dogs died during the administration period. Both male and female dogs given 200 mg/kg and those given 100 mg/kg underwent body weight decrease and inhibition of body weight increase, respectively. Enlargement of liver cells occurred in male dogs given 200 mg/kg and female dogs given 100 or 200 mg/kg. There were no further findings, even histopathologically, which showed any toxic effect of the drug. The maximum non-toxic dose of this drug was considered to be 30 mg/kg.

Animals↗
PubMed1981

Oral kinesthesia in patients with Duchenne muscular dystrophy.

In trials on normal subjects and patients with Duchenne muscular dystrophy (DMD), interdental dimension discrimination (IDD) was tested by assessing the ability of subjects to discriminate between pairs of sticks of different dimensions held between the upper and lower teeth. The IDD ability of the DMD patients was significantly inferior to that of the normal subjects. Further, DMD patients tended to overestimate the dimension of the first stick of each pair even more than did normal subjects. Vibration applied to the mandible seemed to lessen such inaccuracies of oral kinesthesia in the DMD patients. These results are compatible with the idea that muscle receptors, especially muscle spindles in jaw closing muscles, are mainly responsible for IDD.

Adolescent↗
PubMed1981

Repair of ultraviolet radiation damage in xeroderma pigmentosum cells belonging to complementation group F.

DNA-repair characteristics of xeroderma pigmentosum belonging to complementation group F were investigated. The cells exhibited an intermediate level of repair as measured in terms of (1) disappearance of T4 endonuclease-V-susceptible sites from DNA, (2) formation of ultraviolet-induced strand breaks in DNA, and (3) ultraviolet-induced unscheduled DNA synthesis during post-irradiation incubation. The impaired ability of XP3YO to perform unscheduled DNA synthesis was restored, to half the normal level, by the concomitant treatment with T4 endonuclease V and ultraviolet-inactivated Sendai virus. It is suggested that xeroderma pigmentosum cells of group F may be defective, at least in part, in the incision step of excision repair.

Adult↗
PubMed1981

DNA repair in Bloom's syndrome fibroblasts after UV irradiation or treatment with mitomycin C.

Sensitivities to UV and mitomycin C (MC) of fibroblasts obtained from 3 Japanese patients with Bloom's syndrome (BS) were studied. One BS strain was more sensitive to UV than normal cells only in colony-forming ability. Other responses to UV, such as unscheduled DNA synthesis, host-cell reactivation and removal of UV-endonuclease-susceptible sites, were normal in all 3 strains. These BS strains were more sensitive to MC than were normal cells. However, the amounts of unscheduled DNA synthesis after treatment with MC in BS cells did not differ from those in normal cells.

Cells, Cultured↗
PubMed1980

Unscheduled DNA synthesis induced by 4-nitroquinoline-1-oxide in xeroderma pigmentosum cells and their complementing heterodikaryons.

Unscheduled DNA synthesis (UDS) induced by 4-nitroquinoline-1-oxide (rNQO) in the complementation groups A to E and variant xeroderma pigmentosum (XP) cells, and various pairs of complementing XP heterokaryons were investigated. The pattern of UDS induced by various concentrations of 4NQO in normal cells was quite different from those in groups A to D XP cells. The patterns of UDS in group E and variant XP cells were indistinguishable from those of normal cells under our experimental conditions. The levels of UDS induced by 5 x 10(-6) M 4NQO were 13% of normal in group A, 9% in group B, 17% in group C, 25% in group D. The heterokaryons obtained by pair-wise fusions between different complementation groups of XP strains showed restored UDS induced by 5 x 10(-6) M 4NQO, while the dikaryons obtained from fusion between the same groups did not.

4-Nitroquinoline-1-oxide↗
PubMed1980

Cytotoxic effects of protease inhibitors on human cells. 2. Effect of elastatinal.

Effects of elastatinal, a protease inhibitor, on DNA repair and its cytotoxicity were investigated in normal human, xeroderma pigmentosum and Chinese hamster V79 cells. There were no effects of elastatinal on DNA repair and UV-induced sister chromatid exchanges, and all 3 cell lines demonstrated essentially the same sensitivity to the cytotoxic effect of elastatinal. These results were quite different from those by antipain, another protease inhibitor, and caffeine.

Animals↗
PubMed1980

Cytotoxic effects of protease inhibitors on human cells. 1. High sensitivity of xeroderma pigmentosum cells to antipain.

Antipain had little effect on UV-survival and UV-induced sister chromatid exchanges in normal and xeroderma pigmentosum (XP) cells, suggesting that it may not affect DNA repair. Antipain itself produced a small, but significant, amount of sister chromatid exchanges. XP cells showed very high sensitivity to the cytotoxic effect of antipain, but an SV40-transformed XP cell strain did not demonstrate high sensitivity.

Adolescent↗
PubMed1980

Bloom's syndrome in a Japanese girl.

Clinical, cytogenetic, and immunological data of a 5-year-old Japanese girl with Bloom's syndrome are described. Growth deficiency, photosensitivity, and a very mild facial telangiectatic erythema were present. Cytological studies revealed chromosomal aberrations and the characteristic high frequency in sister chromatid exchanges. Immunological studies showed that the serum levels of IgM and IgA, but not IgG, were abnormally low as compared to the age-matched control values and that the generation of cytoplasmic immunoglobulin-producing cells in the peripheral blood lymphocytes, which was evaluated in the in vitro pokeweed mitogen-stimulated cultures, was markedly reduced.

Abnormalities, Multiple↗
PubMed1980

Bloom's syndrome in a Japanese boy with lymphoma.

A 14-year-old boy with malignant lymphoma was identified as having Bloom's syndrome after he was shown to display a characteristically elevated frequency of spontaneous sister-chromatid exchanges. Frequencies of sister-chromatid exchanges per nucleus were 80.7 in blood lymphocytes and 29.9 in dermal fibroblasts. Clinical features, although suggestive of Bloom's syndrome, were not clear enough to permit the diagnosis. This is the first confirmed case of this rare genetic disorder in Japan, and in Asia.

Abnormalities, Multiple↗
PubMed1979

A seventh complementation group in excision-deficient xeroderma pigmentosum.

Cells from a xeroderma pigmentosum patient XP2BI who has reached 17 years of age with no keratoses or skin tumours constitute a new, 7th complementation group G. These cells exhibit a low residual level of excision repair, 2% of normal after a UV dose of 5 J/m2 and an impairment of post-replication repair characteristic of excision-defective XPs. They are also sensitive to the lethal effects of UV and defective in host-cell reactivation of UV-irradiated SV40 DNA.

Adolescent↗
PubMed1978

Reflex activation of extrinsic tongue muscles by jaw closing muscle proprioceptors.

Depression of the mandible in the decerebrate cat induced retraction of the tongue. The mechanism of this jaw-tongue reflex was analyzed by recording electromyographic activity from the temporal and styloglossal muscles as representative masticatory and extrinsic tongue muscles, respectively. Tongue muscle activity was elicited when the mouth was opened beyond 10 degrees while the threshold for the masticatory muscle activities was around 2 degrees. Neither sectioning of the masseteric nerve nor anesthetization of the temporomandibular joint capsule affected the tongue muscle activities. In contrast, exfoliation of the temporal muscle from the temporal bone greatly reduced the effects of jaw depression. When the isolated coronoid process of the mandible was stretched downwards, activities were evoked in the tongue muscle. Repetitive electrical stimulation at a frequency of 100 Hz to the temporal nerve activated the tongue muscle, and the threshold of reflex activation was between 1.3 and 1.7 times threshold of the temporal nerve. Vibratory stimuli applied to the mandible at frequencies below 130 Hz were also effective in evoking tongue muscle activity. However, when the frequency was above 135Hz, tongue muscle activity was not induced although activity was still observed in the masticatory muscles. These results indicate that the jaw-tongue reflex is elicited mainly by proprioceptors in the temporal muscle, and that they may probably be the Golgi tendon organs and the secondary endings rather than the primary endings of the muscle spindle.

Animals↗