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Biomedical subjects

I Watanabe

Publications and source records attributed to I Watanabe.

At least 577 records · Page 32Linked to original sources
PubMed1979

Nitrogen-fixing (acetylene redution) activity and population of aerobic heterotrophic nitrogen-fixing bacteria associated with wetland rice.

Nitrogen-fixing activity associated with different wetland rice varieties was measured at various growth stages by an in situ acetylene reduction method after the activities of blue-green algae (cyanobacteria) in the flood water and on the lower portion of the rice stem were eliminated. Nitrogen-fixing activities associated with rice varieties differed with plant growth stages. The activities increased with plant age, and the maximum was about at heading stage. The nitrogen fixed during the whole cropping period was estimated at 5.9 kg of N per ha for variety IR26 (7 days) and 4.8 kg of N per ha for variety IR36 (95 days). The population of aerobic heterotrophic N(2)-fixing bacteria associated with rice roots and stems was determined by the most-probable-number method, using semisolid glucose-yeast extract and semisolid malate-yeast extract media. The addition of yeast extract to the glucose medium increased the number and activity of aerobic heterotrophic N(2)-fixing bacteria. The glucose-yeast extract medium gave higher counts of aerobic N(2)-fixing bacteria associated with rice roots than did the malate-yeast extract medium, on which Spirillum-like bacteria were usually observed. The lower portion of the rice stem was also inhabited by N(2)-fixing bacteria and was an active site of N(2) fixation.

Journal Article↗
PubMed1979

Propagation of ribonucleic acid coliphages in gnotobiotic mice.

To clarify the propagation cycle of bacteriophages in their natural habitats, we tested whether animals could support ribonucleic acid (RNA) phage propagation in their intestines, using germfree mice as the test animal. Propagation of four different antigenic types of RNA phages was tested. No detectable propagation or colonization of RNA phages was observed either in germfree mice or in gnotobiotic mice infected with the F- strain of Escherichia coli. Propagation or colonization was observed when RNA phages were orally introduced into gnotobiotic mice harboring the F+ or F' strain of E. coli. These results were consistent with data for in vitro propagation experiments. Fecal titers of phages were monitored over 24 to 98 days and were found to vary from 10(5) to 10(11) plaque-forming units per g of feces. Streptomycin administration gradually led to the disappearance of bacteria and, concomitantly, the RNA phages. Phages recovered from gnotobiotic mice feces included some of novel antigenic types. The bacterial isolates recovered from gnotobiotic mice harboring F+ bacteria included the original F+ strain, strains which had become F-, and some which had become inefficient hosts for the propagation of RNA phages.

Animals↗
PubMed1979

Epidemiological survey of definite cases of Meniere's disease collected by the seventeen members of the Meniere's Disease Research Committee of Japan in 1975--1976.

Between Aril 1975 and December 1976, the second nationwide survey of Meniere's disease in Japan was made by the 17 members of the Meniere's Disease Research Committee of Japan. The epidemiological data from 520 patients with definite Meniere's disease were analyzed in comparison with those from the 126 patients in the non-Meniere vertiginous group (Control A) and the 228 patients in the rhinolaryngological group (Control B). The male:female ratio of definite cases of Meniere's disease was almost the same, and the age distribution peaked at the age group of 40--49 years for males, while the peak for females was at the age group of 30--39 years. 5.8% of the 520 patients had a close relative who also suffered from Meniere's disease. From the epidemiological features, it may appear that the occurrence of vertiginous attacks in Meniere's disease is influenced much more by individual than by environmental factors. However, this feature can be considered as another evidence of the psychosomatic disorders involved in Meniere's disease.

Age Factors↗
PubMed1979

Cystic lesions associated with intracranial meningiomas.

Three unusual cases of large, peritumoral cystic lesions associated with intracranial meningiomas are reported. In each case, the cyst caused difficulty in the interpretation of the computed tomogram when the latter was considered as a diagnostic test by itself, but the composite information obtained from the clinical history, cerebral angiography, and a radionuclide brain scan led to the correct preoperative diagnosis. The cyst was extrinsic to the tumor and contained xanthochromic fluid with a high protein content. The cyst wall consisted of brain parenchyma that showed glial cell proliferation (confirmed by the presence of glial fibrillary acidic protein by immunoperoxidase staining).

Aged↗
PubMed1979

Syntheses of sporaricin analogues, 2-deoxy-4-N-glycyl-6-O-(alpha-nebrosaminyl)fortamine and its 3-de-O-methyl compound.

2-Deoxy-4-N-glycyl-6-O-(alpha-nebrosaminyl)fortamine (21) and 3-de-O-methyl-2-deoxy-4-N-glycyl-6-O-(alpha-nebrosaminyl)fortamine (27) were prepared starting from lividamine. The syntheses include four key steps, that is, transformation of 2-deoxystreptamine moiety of lividamine to 4-N,3-O-didemethyl-2-deoxyfortamine, selective 4-N-methylation of the new aminocyclitol moiety, selective attachment of a glycyl residue to the methylamino group at C-4 and selective amination at C-6'.

Aminoglycosides↗
PubMed1979

Amplification of growth inhibition by glucocorticoid on L5178Y and L1210 lymphoblasts in vivo.

One component of a factor in Proteus mirabilis (Factor 1) which specifically amplifies the induction of several liver enzymes by glucocorticoid in target cells also increases the growth inhibition of glucocorticoid on the ascitic form of L1210 cells and solid tumors of L5178Y lymphoblasts in vivo. The growth of L5U78Y and L1210 lymphoblasts was inhibited by a triamcinolone acetonide dose of over 0.5 to 1.0 mg/kg body weight. Factor 1 increased the inhibitory effect of a triamcinolone acetonide dose of less than 4.0 mg/kg bodyweight but had little effect on the effects of doses of over 4.0 mg. Factor 1 (10 biological units/kg body weight) itself also caused marked inhibition of the growth of these lymphoblasts without affecting the body weight or adrenal gland weight, its effect being equivalent to that of 3- to 4-mg/kg body weight doses of triamcinolone acetonide alone. There was no significant difference in the level of plasma total corticoids or that of plasma adrenocorticotropic hormone between rats treated with 0.9% NaCl solution or those treated with Factor 1, and Factor 1 had no cytotoxic effec on cultured L5178Y lymphoblasts. Thus, Factor 1 may amplify the effect of physiological level of glucocorticoid in mice sufficiently to inhibit the growth of these lymphoblasts without causing any significant side effects to the host animal.

Adrenal Cortex Hormones↗
PubMed1979

Enhancement of mammalian cell killing by 5-fluorouracil in combination with X-rays.

The enhanced cytocidal effect of a combination of X-rays and 5-fluorouracil was investigated by means of colony-forming ability in mouse L-cells. Cells were treated with 5-fluorouracil immediately preceding (preirradiation treatment) or following (postirradiation treatment) irradiation. In either pre- or postirradiation treatment with various concentrations of the drug for a fixed time, the enhanced effect was augmented with increasing concentrations of 5-fluorouracil up to 20 microgram/ml. When cells were subjected to postirradiation treatment with a fixed concentration of drug for varying times, the cytocidal effect was further enhanced with increasing duration of drug treatment. In preirradiation treatment, however, drug treatment for longer than 3 hr did not exhibit any further enhancement. Postirradiation treatment with 5-fluorouracil to synchronous cells at various ages demonstrated enhancement at all ages during the cell cycle. The greatest enhancement was observed in the DNA-synthetic phase. Postirradiation treatment with 5-fluorouracil (2.5 microgram/ml) for 24 hr markedly reduced the width of the shoulder of the X-ray survival curve without significantly altering the slope of the exponential portion of the curve. Recovery from sublethal radiation damage was not suppressed by 5-fluorouracil when cells were treated with drug between fractionated X-ray doses. These results indicate that damages caused by 5-fluorouracil and X-rays interact additively to induce cell killing.

Animals↗
PubMed1979

Progressive multifocal leukoencephalopathy: cerebral mass lesions.

In 9% of reported cases, progressive multifocal leukoencephalopathy presents clinically and radiographically as a focal cerebral mass lesion. Initial misdiagnosis may occur, leading to surgery for suspected malignancies. The electroencephalographic, radiologic, and histopathologic findings in such cases are discussed.

Diagnosis, Differential↗
PubMed1979

Postoperative mucoceles of the maxillary sinus.

Apparently, the incidence of postoperative maxillary sinus mucoceles is greater in Japan than in the Western world. Between 1967 and 1976 at the Tokyo Medical and Dental University Hospital, Department of Otorhinolaryngology, 132 patients had the diagnosis of mucoceles of the maxillary sinus. Of these patients, 131 (99%) had histories of previous maxillary sinus surgery. A number of etiologic mechanisms are probably involved in producing these mucoceles.

Adolescent↗
PubMed1978

Identification of low chlorinated biphenyls in human milk by gas chromatography--mass spectrometry.

Trichlorobiphenyl and tetrachlorobiphenyls in human milk were analysed by gas chromatography--mass spectrometry and mass fragmentography using silicone OV-1 and Apiezon L grease as stationary phases. Low-chlorinated biphenyls had been considered to be excreted rapidly from the body, but in this work quantities of tri- and tetrachlorobiphenyls amounting to approximately 30% of the total of polychlorinated biphenyls (PCBs) accumulated in the milk were identified. This result is important in relation to the quantification of PCBs and in studies of the mechanism of biological degradation.

Chromatography, Gas↗
PubMed1978

Dermatoleukodystrophy with neuroaxonal spheroids.

A Japanese brother and sister, the progeny of healthy parents, were born with thickened, wrinkled skin and died between the age of 2 and 3 years with a progressive cerebral disease characterized by generalized mental and motor impairment. Postmortem neuropathological studies disclosed a remarkable leukodystrophy in which multiple axonal spheroids were the outstanding feature. Ultrastructurally, the spheroids contained granules resembling ceroid-lipofuscin bodies. Similar granules were found in degenerating oligodendrocytes and in Schwann cells. The skin showed hypercellular and sclerotic features, suggestive of a genodermatosis. This combined neurologic and dermatologic syndrome, which, to our knowledge, has not hitherto been recognized, may well result from a genetically determined metabolic disorder, the nature of which still remains undisclosed.

Axons↗
PubMed1978

Neurotoxicity of intrathecal gentamicin: a case report and experimental study.

Distinctive lesions occurred in the brainstem of a 59-year-old patient who had had recent Pseudomonas aeruginosa meningitis treated with parenteral and intrathecal gentamicin sulfate. The lesions were multiple, minute, and discrete, and were characterized by loss of axons, spongiosis, axonal swelling with frequent calcification, loss of astroglia and oligodendroglia, and slight inflammatory response. These lesions were restricted to the myelinated fiber bundles of the pons and mesencephalon. Because similar lesions can occur with other intrathecally administered medications and emboli to the brain, an experimental study in rabbits was done. Similar lesions were produced in normal adult rabbits after a single intracisternal injection of gentamicin sulfate with or without preservative at doses equivalent to 50 and 100 times the human therapeutic dose. Lesions were not seen after injection of normal saline, preservative, or gentamicin sulfate with preservative at doses equivalent to 1 and 10 times the human therapeutic dose. A direct relationship was observed between the cerebrospinal fluid concentrations of gentamicin, brain tissue concentrations of gentamicin, and occurrence of the lesions.

Animals↗