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Biomedical subjects

T Iida

Publications and source records attributed to T Iida.

At least 307 records · Page 17Linked to original sources
PubMed1992

Prevalence of Listeria (spp.) in wild rats captured in the Kanto area of Japan.

In the Kanto area a total of 245 wild rats were captured. All rats captured in Ikebukuro (110 rats) and 9 out of 41 rats in Yokohama were Rattus rattus, and all other 126 rats were Rattus norvegicus. In Kashima and Ikebukuro, listeria was isolated from 28 rats (77.8%) and 27 rats (24.5%), respectively, but in the other 4 areas listeria was isolated from 0-7% rats. Listeria monocytogenes was isolated from 12 rats (10.9%) captured in Ikebukuro and 2 rats in Kashima and Numazu. The frequent isolation of L. monocytogenes in buildings suggests the possibility of R. rattus as a reservoir of L. monocytogenes and the continual environmental contamination in buildings by L. monocytogenes.

Animals↗
PubMed1992

[Retinal damage induced by visible blue and near-infrared light of an operating microscope].

The authors evaluated possible hazards to the retina caused by the longer wavelength component in the illumination system of the surgical microscope. Thirty six pigmented and eleven albino rabbit eyes were exposed to blue or near-infrared light for 60 minutes. Ophthalmoscopically visible light damage to the retina developed in 4 of 5 pigmented rabbit eyes after illumination at a power setting of 8 mW/cm2 for blue and 50 mW/cm2 for near-infrared light. These power settings were equivalent to those used in clinical tests. The light damage developed immediately after illumination with near-infrared light and a few days after illumination with blue light. No light damage developed in albino rabbits with near-infrared light at current power setting. The findings suggest the possibility that clinical retinal damage may develop in human eyes when exposed to near-infrared light from surgical microscopes.

Animals↗
PubMed1992

Plasmapheresis in the Tokai University Medical Center, 1983-1989.

There were 634 instances of plasmapheresis performed on 152 patients in the Kidney Center, Tokai University Hospital, in the seven year period from Jan. 1983 to Dec. 1989. The average number of plasmapheresis treatments per patient was highest for those with neurological and dermatological disease (6.7), followed by liver disease (5.6), and drug intoxication (1.2). The major treatment modalities for the liver, collagen, drug intoxication, hematologic, neurologic and hyperlipidemic disorders were plasma exchange (PE) and double filter plasmapheresis (DFPP). Recently, however, the use of plasma perfusion (PP) and immunoadsorbent plasma perfusion (IPP) has been increasing because of their ability to selectively adsorb various pathologic macromolecules.

Collagen Diseases↗
PubMed1992

[Spectral absorption characteristics of ocular tissues].

We studied the ocular spectral characteristics of monkey and rabbit eyes in the range of 300 to 900 nm. Measurements were performed on dissected specimens of the cornea, lens, vitreous, sensory retina and retinal pigment epithelium (RPE) plus choroid. Xanthophyll and monkey blood were also studied. Components of the ocular media showed high absorption over the ultraviolet range. The absorption curve of the sensory retina was similar to that of the ocular media. RPE plus choroid showed high absorption over the whole spectral range, with gradual decrease in absorption above 600 nm. The specific absorption curve of both xanthophyll and blood became manifest only when diluted to more than 1:20,000 in the former and to more than 1:100 in the latter. The spectral absorption of the ocular tissue thus became specific only when the thickness or density of the tissue was within a certain range.

Animals↗
PubMed1992

[Fluorescein angiographic observation of cellular changes in the retinal pigment epithelium after laser photocoagulation].

Lesions in the retinal pigment epithelium (RPE) of 16 pigmented rabbits were produced by dye laser photocoagulation using with three different wavelengths: 514, 577 and 630 nm. The power setting and exposure time was the same throughout. The size of the coagulation spot was set either at 500 or 1,000 microns. The retinal lesions were examined by high resolution fluorescein angiography on day 2, 7 and 30 after photocoagulation. Scanning electron microscopic examination of RPE was also performed in selected cases. On fluorescein angiography, the damaged RPE cells appeared as negative fluorescent spots with intense fluorescent margins, throughout the period of observation. The size of the lesion also remained constant. There were no difference in the damage or recovery of RPE cells in relation to the 3 different laser wavelengths. In some area of lesion, the fluorescein angiographic findings closely matched those observed by scanning electron microscopy.

Animals↗
PubMed1992

[A case of invasive thymoma with retroperitoneal recurrence].

A case of invasive thymoma with retroperitoneal recurrence is reported. A 55-year-old man with invasive thymoma (Masaokas classification, Stage IVa) underwent thymo-thymectomy, partial resection of left upper lobe, resection of phrenic nerve and partial resection of parietal pleura on March 14, 1989. Histological findings revealed thymoma with predominantly lymphocytic type. Two years after the operation, the tumor of retroperitoneal recurrence was discovered in abdominal CT. This retroperitoneal tumor was huge in size (16 x 12 cm) and extended into posterior mediastinum via aortic hiatus. The patient underwent resection of tumor through thoracotomy and laparotomy on April 23, 1991, after two cycles of chemotherapy. Histological findings revealed thymoma with predominantly lymphocytic type. This case was rare among patients with recurrence of thymoma as far as the site of recurrence is concerned.

Humans↗
PubMed1991

Agonist-induced calcium signaling is impaired in fibroblasts overproducing inositol 1,3,4,5-tetrakisphosphate.

The proposed Ca(2+)-signaling actions of inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), formed by phosphorylation of the primary Ca(2+)-mobilizing messenger, inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), were analyzed in NIH 3T3 and CCL39 fibroblasts transfected with rat brain Ins(1,4,5)P3 3-kinase. In such kinase-transfected cells, the conversion of Ins(1,4,5)P3 to Ins(1,3,4,5)P4 during agonist stimulation was greatly increased, with a concomitant reduction in Ins(1,4,5)P3 levels and attenuation of both the cytoplasmic Ca2+ increase and the Ca2+ influx response. This reduction in Ca2+ signaling was observed during activation of receptors coupled to guanine nucleotide-binding proteins (thrombin and bradykinin), as well as with those possessing tyrosine kinase activity. Single-cell Ca2+ measurements in CCL39 cells revealed that the smaller averaged Ca2+ response of enzyme-transfected cells was due to a marked increase in the number of cells expressing small and slow Ca2+ increases, in contrast to the predominantly large and rapid Ca2+ responses of vector-transfected controls. There was no evidence that high Ins(1,3,4,5)P4 levels promote Ca2+ mobilization, Ca2+ entry, or Ca2+ sequestration. These data indicate that Ins(1,4,5)P3 is the major determinant of the agonist-induced Ca2+ signal in fibroblasts and that Ins(1,3,4,5)P4 does not appear to contribute significantly to this process. Instead, Ins(1,4,5)P3 3-kinase may serve as a negative regulator of the Ca(2+)-phosphoinositide signal transduction mechanism.

3T3 Cells↗
PubMed1991

Studies on steroids. CCLIII. Capillary gas chromatographic behaviour of diethylhydrogensilyl-diethylsilylene derivatives of stereoisomeric bile acids.

The capillary gas chromatographic behaviour of diethylhydrogensilyl (DEHS) ethers and/or diethylsilylene (DES) derivatives of fifty bile acids including 4- and 6-hydroxylated compounds is described. The methylene unit (MU) values of methyl and pentafluorobenzyl esters of bile acids were determined as their trimethylsilyl (TMS), dimethylethylsilyl (DMES) ethers and DEHS-DES derivatives. The differences in methylene unit values between the corresponding TMS ethers and DMES ethers or DEHS-DES derivatives were used for estimating the number and stereochemistry of hydroxyl groups on the steroid nucleus. On treatment with the silylating agent N,O-bis (diethylhydrogensilyl)trifluoroacetamide, bile acids possessing isolated hydroxyl in addition to diaxial trans-glycol groups were easily converted into the DEHS ehters, whereas those having a vicinal glycol group except for the diaxial group were converted into cyclic DES derivatives. The mass spectrometric properties obtained with negative-ion chemical ionization detection are discussed.

Bile Acids and Salts↗
PubMed1991

Interactions between calcium and protein kinase C in the control of signaling and secretion in pituitary gonadotrophs.

Single pituitary gonadotrophs exhibit episodes of spontaneous fluctuations in cytoplasmic calcium concentration [( Ca2+]i) due to entry through voltage-sensitive calcium channels (VSCC) and show prominent agonist-induced oscillations in [Ca2+]i that are generated by periodic release of intracellular Ca2+. Gonadotropin releasing hormone (GnRH) elicited three types of Ca2+ responses: at low doses, subthreshold, with an increase in basal [Ca2+]i; at intermediate doses, oscillatory, with dose-dependent modulation of spiking frequency; and at high doses, biphasic, without oscillations. Elevation of [Ca2+]i or activation of protein kinase C (PKC) did not influence the frequency of agonist-induced [Ca2+]i spikes but caused dose-dependent reductions in amplitude for all types of Ca2+ response. Stimulation of transient Ca2+ spikes by GnRH was followed by inhibition of the spontaneous fluctuations. GnRH also reduced the ability of high extracellular K+ to promote Ca2+ influx through VSCC. Activation of PKC by phorbol esters stimulated Ca2+ influx in quiescent cells but inhibited influx when VSCC were already activated, either spontaneously or by high K+. In contrast to their biphasic actions on [Ca2+]i, phorbol esters exerted only stimulatory actions on gonadotropin release, even when Ca2+ influx was concomitantly reduced. However, pituitary cells had to be primed with an appropriate [Ca2+]i level before exocytosis could be amplified by PKC. In PKC-depleted cells, all actions of phorbol esters on Ca2+ entry and amplitude modulation, and on LH release, were abolished. GnRH-induced LH secretion was also significantly reduced, especially the plateau phase of the response. These data indicate that Ca2+ and PKC serve as interacting signals during the cascade of cellular events triggered by agonist stimulation, in which Ca2+ turns cell responses on or off, and PKC amplifies the positive and negative effects of Ca2+.

Alkaloids↗
PubMed1991

Macrophage chemotactic factor partially purified from granulomatous inflammation.

Pathophysiological roles of macrophage chemotactic factor (MCF) in granulomatous inflammation were investigated. MCF was extracted in 10 mM phosphate-buffered saline, pH 7.4, from experimentally produced epithelioid cell granulomas in the liver and skin of mice. MCF activity reached a peak in the lesions prior to the time when granulomatous inflammation became maximal. MCF was then purified from 10-week-old hepatic granulomas and 2-week-old skin lesions by gel filtration, ion exchange column chromatography, and HPLC gel filtration. MCF from either liver or skin had a molecular weight about 650 kDa. MCF from hepatic granulomas was coupled to Affi-Gel beads and transplanted subcutaneously into naive mice. In vivo macrophage chemotaxis was observed around the beads and the cells formed a sheet, but organization of macrophages into granulomas did not occur with the MCF-active fractions. Macrophage chemotaxis alone is insufficient to elicit granulomatous inflammation.

Animals↗
PubMed1991

An improved noninfectious murine skin model of organized granulomatous inflammation.

An improved model of granulomatous inflammation in skin was developed by second passage skin grafting of isolated, lyophilized skin granulomas, originally elicited in naive mice by inoculations of lyophilized hepatic schistosome egg granulomas. The tissue reaction is caused by a single exposure to a noninfectious, acellular granulomagenic stimulus and occurs in healthy mice free of systemic disease. The model should prove useful for isolation of granuloma initiation factor(s). Furthermore, because there is a time lag before new granuloma formation begins, a window exists for analytical dissection of the initiation process. In this study we described the responses of host cells by autoradiography, and light and electron microscopy. The activity of angiotensin-converting enzyme and proline-specific endopeptidase showed a modulation during granuloma formation. In addition we found that severe immunosuppression with high dose cyclosporine therapy did not alter granuloma formation, supporting the idea that initiation of organized granulomas is T-cell independent.

Animals↗
PubMed1991

The clinical value of tissue carcinoembryonic antigen in breast cancer.

The relationship of tissue carcinoembryonic antigen (CEA) to clinicopathological factors and prognosis was investigated in 168 patients with invasive ductal carcinoma of the breast. Tissue CEA was determined by radioimmunoassay and a level of 5.1 ng/ml or more considered to be positive. Tissue CEA was positive in 31.5 per cent of the patients overall and, of the clinicopathological factors, tumor size and the presence or absence of lymph node involvement were not found to be correlated with tissue CEA. However, the tissue CEA positivity rate was significantly higher in patients who had four or more metastatic lymph nodes (p less than 0.01). Tissue CEA-positive patients showed earlier recurrence than CEA-negative patients (p less than 0.01) and had a poorer outcome (p less than 0.05). Thus, tissue CEA is considered useful as a prognostic index for primary breast cancer patients.

Adult↗
PubMed1991

Developmental arrest at early stages of Chinese hamster embryos homozygous for chromosomal rearrangements.

Forty-three Chinese hamster stocks with autosomal rearrangements produced by X-irradiation were used. These rearrangements, 38 reciprocal translocations and 5 inversions, were chromosomally balanced. Heterozygotes for these rearrangements were all fertile and morphologically normal in both sexes except for one line with growth retardation. By crossing male and female heterozygotes for the same rearrangements, homozygotes were obtained in 37 lines. In the remaining 6 lines (5 with reciprocal translocations and 1 with an inversion), no homozygotes were viable. These 6 lines revealed arrested development of homozygous embryos at the two-cell stage, around the eight-cell stage, and after implantation, respectively. The bands of the breakpoints of rearrangements associated with lethality of homozygous embryos were different for each rearrangement. These results suggest that abnormal expression including embryonic lethality in homozygotes may be due to an influence of genes at the breakpoints.

Animals↗
PubMed1991

Immunogenetic influences on skin granuloma formation in mice.

Genetic influence on the development of granulomatous tissue reaction was investigated in C57BL/6 mice. Granulomas developed in the skin of euthymic C57BL/6 mice by transplantation of lyophilized hepatic granulomas were excised and lyophilized. The tissue mass free of parasite egg antigen and living cells was grafted into the skin of euthymic, athymic (nu/nu), and beige (bg/bg) C57BL/6 mice. Histological changes at the skin sites were studied weekly by light microscopy, and cells in newly developed granulomas at 6 weeks after grafting were examined by electron microscopy. Granulomatous inflammation occurred in all the variants but morphometric analysis showed that granulomatous inflammation was the most extensive in beige mice and least in athymic mice. The differences in the degree of tissue reaction were also quantified by measuring angiotensin converting enzyme and prolyl endopeptidase. Statistically significant differences among the animals with varying genetic background were confirmed by the marker enzyme activity. The findings confirm that initiation of a granulomatous response does not require T cells but T cell function is important for full expression of the reaction, while NK cell activity seems to suppress granuloma formation.

Animals↗
PubMed1991

Potential bile acid metabolites. 17. Synthesis of 2 beta-hydroxylated bile acids.

The 2 beta-hydroxylated derivatives of lithocholic, chenodeoxycholic, deoxycholic, and cholic acids were synthesized from the respective parent bile acids by established procedures. The principal reactions involved were (1) bromination of 3-oxo formylated bile acids in N,N-dimethylformamide, (2) rearrangement and substitution of the resulting 4 beta-bromo-3-oxo derivatives to the 2 beta-acetoxy-3-oxo compounds with potassium acetate, and (3) reduction to the 2 beta-acetoxy-3 alpha-hydroxy compounds with tert-butylamine-borane complex. As for the prepared 2 beta-hydroxylated bile acids with a diequatorial trans-glycol structure, proton and carbon-13 nuclear magnetic resonance spectroscopic and gas-liquid chromatographic/mass spectrometric properties are discussed.

Acetates↗