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Biomedical subjects

T Yuasa

Publications and source records attributed to T Yuasa.

At least 109 records · Page 6Linked to original sources
PubMed1997

Severe cutaneous and venous damage after DIC therapy.

A 79-year-old woman with skin ulcers caused by disseminated intravascular coagulation (DIC) therapy is reported. The patient had been treated by injection of drugs, including gabexate mesilate, into the right great saphenous vein. The maximum concentration of gabexate mesilate was calculated as 0.893%. Although the drugs did not extravasate, purpura initially appeared around the affected vein, followed by brown pigmentation with infiltration and ulcers with widely necrotic tissue from the middle portion of her thigh to the malleolus along her right great saphenous vein. As the ulcer showed no tendency to heal for more than 3 months, surgical debridement and skin grafts were performed.

Aged↗
PubMed1997

Osteoclasts are present in gp130-deficient mice.

Interleukin (IL)-6, IL-11, leukemia inhibitory factor, and oncostatin M similarly induce osteoclast formation in cocultures of osteoblastic cells and bone marrow cells. These cytokines share a common signal transducer, gp130, which forms a receptor complex with the specific receptor for each cytokine. To investigate the role of gp130 in osteoclast development, we examined bone tissues in gp130-deficient and wild-type newborn mice of the ICR background. Soft x-ray radiographs and microfocus x-ray computed tomographs revealed that bone marrow cavities were present in tibiae and radii of both wild-type and gp130-deficient mice. Microfocus x-ray computed tomography and histological examination demonstrated a decrease in the amount of trabeculae at the metaphysial region in tibiae and radii of the gp130-deficient mice compared with the wild-type mice. The number ofosteoclasts in gp130-deficient mice was about double that in the wild-type mice. There were no apparent differences in the distributions of alkaline phosphatase-positive osteoblasts and the osteoid surface on the trabecular bone at the metaphysial region between the wild-type and gp130-deficient mice. The volume of mineralized trabecular bones was also decreased at mandibulae, accompanied by the increased number of osteoclasts in gp130-deficient mice compared with the wild-type and heterozygous mice. These results suggest that the formation of osteoclasts is not solely dependent on gp130 signaling, at least during fetal development. The osteoclastic bone resorption in gp130-deficient mice may be caused by the functional redundancy of bone-resorbing hormones and cytokines other than those of the IL-6 family.

Animals↗
PubMed1997

Down-regulation of gap junctional intercellular communication between osteoblastic MC3T3-E1 cells by basic fibroblast growth factor and a phorbol ester (12-O-tetradecanoylphorbol-13-acetate).

To address the relation between osteoblast growth and cell-to-cell communication, we examined the effects of basic fibroblast growth factor (bFGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA), both potent stimulators of osteoblastic proliferation, on gap junctional intercellular communication between osteoblastic MC3T3-E1 cells. The level of intercellular communication was estimated by a photobleaching method. TPA inhibited the degree of intercellular communication in two different time-dependent manners. The early (< 1 h) inhibition by TPA was consistent with an increase in the phosphorylation of connexin 43 (Cx43). The later inhibition was caused by reduction in the total amount of Cx43 on the plasma membrane, due to the decrease in the level of Cx43 transcripts. These qualitative and quantitative modulations by TPA were inhibited by a selective inhibitor of protein kinase C, GF109203X. bFGF also attenuated the gap junctional intercellular communication. However, short exposure (< 5 h) to bFGF did not affect the communication. The fact that the growth factor immediately stimulated the phosphorylation of Cx43 indicates that the phosphorylation site(s) affected by bFGF was not involved in the inhibition of communication. The decrease in the intercellular communication level was detected by the longer exposure (> 8 h) to bFGF and paralleled the decline in the Cx-mRNA level. This inhibitory effect of bFGF was abolished by the addition of a tyrosine kinase inhibitor, herbimycin A. Thus, gap junctional intercellular communication between osteoblasts was down-regulated by osteoblastic mitogens through different mechanisms of the modulation of Cx43.

3T3 Cells↗
PubMed1997

[Progress of the therapy for virus related neurological disorders].

In this review of the therapy of infectious diseases and immune mediated nervous system diseases, we summarized the latest reports of antiviral drugs, immunosuppressants, immuno-modulatory and anti-inflammatory agents. Those include, acyclovir, vidarabine for herpes simplex encephalitis, ganciclovir for cytomegaro virus infection, inosine pranobex for SSPE, steroid therapy, interferon, plasma exchange and high-dose intravenous gamma globulin therapy for HTLV-I associated myelopathy, and multiple sclerosis. Diagnostic application of the PCR and the newly developed neuroimaging techniques, like diffusion weighted MRI, high speed MRI, and SPECT, we now being introduced to enable early recognition of viral infection of the CNS. And since speed of spread of HIV infection through the world, we are needed specific treatment for HIV infection, and various studies including genetic therapy is going on today.

Humans↗
PubMed1997

[The inhibitory effects of Arg-Gly-Asp-Ser on attachment of fibroblasts].

Trabeculectomy often fails because of scarring of the filtering bleb, which is caused by the proliferation of fibroblasts. In this study, we investigated the inhibitory effect of Arg-Gly-Asp-Ser (RGDS) oligopeptide, a cell binding domain of fibronection molecules, on the attachment of fibroblasts in vitro and on scarring of filtering bleb after trabeculectomy on rabbits' eyes. The following results were obtained. 1. RGDS inhibited the attachment of rabbit conjunctival fibroblasts significantly (p < 0.01) when it was added to the culture medium at final concentrations of 2 and 5 mg/ml. 2. The administration of 0.2 ml of RGDS solution (5 mg/ml) into the filtering bleb 3 days after surgery caused significant reductions of intra ocular pressure compared with the control maintained the bleb more than 13 days whereas the blebs of the control eyes disappeared within 6 days (p < 0.01). 3. No complications were caused on the eyeballs of the rabbits by the administration of RGDS.

Animals↗
PubMed1997

Pharmacological profile of the novel antidepressant 4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno-[2,3-d]pyrimidine monohydrate hydrochloride.

This is a first report on the investigation of the antidepressant activity of MCI-225 (4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno[2,3-d]pyrimidine monohydrate hydrochloride, CAS 99487-26-0) in comparison with maprotiline (CAS 10347-81-6), desipramine (CAS 58-28-6), imipramine (CAS 113-52-0) and trazodone (CAS 25332-39-2). MCI-225 inhibited the synaptosomal uptake of noradrenaline (NA, Ki = 35.0 nmol/l), serotonin (5-HT, Ki = 491 nmol/l), and dopamine (Ki = 14,800 nmol/l), although it did not inhibit MAO-A and MAO-B activities. MCI-225 showed high affinity only for the 5-HT3 receptor (Ki = 81.0 nmol/l) among all receptors tested including M1, M2, alpha 1, and H1 receptors. The inhibition of the von Bezold-Jarisch reflex by MCI-225 (ID50 = 22.2 mg/kg, p.o.) suggests its antagonistic action on the 5-HT3 receptor. MCI-225 dose-dependently reduced reserpine-induced hypothermia (0.3-10 mg/kg, p.o.) and potentiated yohimbine-induced lethality (3-100 mg/kg, p.o.) in mice. These effects of MCI-225 were as potent as desipramine and more potent than maprotiline, imipramine and trazodone. MCI-225 and desipramine did not change either 5-HTP-induced head movements or p-CA-induced hyperactivity in rats. In forced swimming tests in rats, the minimum effective doses of MCI-225, maprotiline, desipramine, and imipramine were 1, 30, 10 and 30 mg/kg, p.o., respectively, for 5-days administration. Only MCI-225 had shown its full activity with this short term treatment. MCI-225 (10 mg/kg, p.o.) decreased the REM sleep period without affecting slow-wave sleep or wakefulness in rats. Even at 100 mg/kg, p.o. MCI-225 and trazodone did not inhibit oxotremorine-induced tremor, lacrimation or salivation in mice in contrast with imipramine. These results suggest that MCI-225, which selectively inhibits NA uptake and antagonizes the 5-HT3 receptor, has potential as a new type of potent antidepressant.

Animals↗
PubMed1996

Mammalian mature osteoclasts as estrogen target cells.

The decrease in estrogen levels that follows the onset of menopause causes rapid bone loss, resulting in osteoporosis. However, the mechanism by which this occurs remains unclear, especially concerning the regulation of osteoclasts, i.e. the bone-resorbing cells. Using a pit assay involving isolated mature osteoclasts from rabbit long bones, we found that estrogen inhibited the bone-resorbing activity in a dose- and time-dependent manner. Furthermore, we clarified by Northern analysis that estrogen down-regulated the mRNA levels of cathepsin K/OC-2 and that putative estrogen receptor (ER) mRNA was expressed in these osteoclasts. Moreover, other sizes of mRNAs that hybridized with ER cDNA probe were found in these cells. Our results suggest that osteoclasts may be indeed target cells for estrogen and that estrogen might regulate a part of bone metabolism through osteoclasts.

Animals↗
PubMed1996

Purkinje cells express neuronal nitric oxide synthase after methylmercury administration.

To study the effects of chemical injury on the cerebellar nitric oxide synthase (NOS), we administered methylmercury chloride subcutaneously to mice, 10 mg/kg/day for 9 days. In the methylmercury-treated cerebellum. Purkinje cells were positive both for NADPH-diaphorase and for neuronal NOS. Calcium-dependent NOS activity was increased to 160% of the controls. The present study suggests the ability of Purkinje cells to produce NO through the expression of neuronal NOS.

Animals↗
PubMed1996

Vitamin K2 inhibits osteoclastic bone resorption by inducing osteoclast apoptosis.

In contrast to vitamin K1(VK1), vitamin K2(VK2) inhibited osteoclastic bone resorption by unfractionated bone cells and isolated osteoclasts. To investigate the mechanism of inhibition of osteoclastic bone resorption by VK2, we examined the effect of this vitamin on osteoclast apoptosis using a DNA-binding fluorescent dye, Hoechst 33258. In unfractionated bone cells and isolated osteoclasts on dentin slices, we first demonstrated that VK2 induced osteoclast apoptosis, but VK1 did not. Moreover, cycloheximide inhibited VK2-induced osteoclast apoptosis. These results suggest the possibility that VK2 inhibits osteoclastic bone resorption by targeting osteoclasts to undergo apoptosis, which leads to cell death.

Animals↗
PubMed1996

Surgical removal of submacular hemorrhage using tissue plasminogen activator and perfluorocarbon liquid.

PURPOSE: To assess the result of surgical removal of submacular hemorrhage by using tissue plasminogen activator and perfluorocarbon liquid. METHODS: In 22 consecutive patients (22 eyes), subretinal hemorrhage associated with age-related macular degeneration, which involved the fovea and completely obscured the choroidal vascular pattern, was treated by pars plana vitrectomy. The hemorrhages were liquefied with tissue plasminogen activator, squeezed into the vitreous cavity with perfluorocarbon liquid, and then evacuated. RESULTS: Efficacy of the procedure was judged by the best postoperative corrected visual acuity, which was 20/100 or better in 16 eyes (73%). Submacular hemorrhage recurred in four (18%) eyes, epiretinal membrane formed in three (14%) eyes, and retinal detachment occurred in three (14%) eyes. Best-corrected final visual acuity was improved postoperatively in 18 (82%) of the 22 eyes, unchanged in three (14%) eyes, and decreased in one (5%) eye, final visual acuity was 20/200 or better in 15 eyes (68%) and limited in other eyes by subretinal hemorrhage of greater than 30 days' duration or subfoveal neovascularizations. CONCLUSIONS: Use of tissue plasminogen activator and perfluorocarbon liquid in surgical removal of submacular hemorrhage may improve the outcome of surgery by reducing surgically induced retinal damage.

Aged↗
PubMed1996

Differential effects of fibronectin-derived oligopeptides on the attachment of rabbit lens epithelial cells in vitro.

Among the Arg-Gly-Asp (RGD)-containing sequences that are known to be cell-binding domains of fibronectin, 500 migrograms/ml of Arg-Gly-Asp-Ser (RGDS) and Gly-Arg-Gly-Asp-Ser showed 100% inhibition of the attachment of cultured lens epithelial cells (TOTL-86 cells), when they were added to culture medium and coincubated with the cells for 24 h whereas RGD at concentrations of 500, 1,000 and 2,000 micrograms/ml had no such activity. After 48 h of cocultivation of 800, 400 or 200 micrograms/ml of RGDS with TOTL-86 cells, the percentage of floating cells was 100, 30.1 or 11.1%, respectively. After 144 h of cocultivation with RGDS, the percentage of floating cells was 1.6, 2.4 or 1.9%, respectively, indicating that RGDS was not cytotoxic to lens epithelial cells. However, replacing the medium with fresh medium containing new RGDS peptide resulted in floating of cells. We also studied the inhibitory effect of two other amino acid sequences that are found in cell-binding sites of the fibronectin molecule: Glu-Ile-Leu-Asp-Val-Pro-Ser-Thr (EILDVPST) and Arg-Glu-Asp-Val (REDV). At 500 and 1,000 micrograms/ml, respectively, neither EILDVPST nor REDV has an inhibitory effect on the attachment of TOTL-86 cells, while RGDS at a concentration of 500 micrograms/ml completely inhibited the attachment of the cells in 24 h of incubation.

Amino Acid Sequence↗
PubMed1996

Elevation of cerebral lactate detected by localized 1H-magnetic resonance spectroscopy in migraine during the interictal period.

We used localized 1H-magnetic resonance spectroscopy (MRS) to study the metabolic changes in the brains of patients with migraine during the interictal period. Measurement of metabolite levels in the occipital visual cortex in six normal subjects and six patients disclosed high lactate levels in the five patients who had experienced a migraine attack within the previous 2 months. One patient who had not experienced a migraine attack in the previous 4 years did not show a lactate peak. We speculate that anaerobic glycolysis occurs in the brains of patients with migraine during the interictal period, and a long attack-free period may normalize the subclinical metabolic disturbance.

Adolescent↗
PubMed1996

Immortalization of cells from brains derived from a strain (MSM/MSfB6C3F1) of wild mouse.

Escape from cellular aging is the rate-limiting step of multistep carcinogenesis. While normal human cells invariably undergo cellular aging and almost never spontaneously immortalize, cells derived from rodents such as mice are relatively easily immortalized. In this experiment, we studied the immortalization patterns of cells obtained from brain tissues of an inbred strain (MSM/MSfB6C3F1) derived from wild mice. We established 12 cell strains derived from 12 mouse brains in order to investigate whether these cells show cellular aging in the same fashion as human cells or whether these cells are immortalized as easily as rodent cells reported previously. As a result, all cell strains were immortalized up to about 200 days in culture. One strain immortalized very early, in the first 50 days, four strains immortalized in the last 200 days, and the other seven strains became immortal between 150 and 200 days in culture. All immortalized cell strains showed varying amounts of chromosome abnormalities, numerically and structurally, but no specific changes related to immortalization were detected. Before immortalization, three types of cells, glial-like, polygonal flat-thin, and fibroblast-like cells, were observed in culture, but after immortalization most of the cultures became fibroblastic. From these results, we concluded that fibroblast-like cells derived from brains of these mice immortalized in like fashion to fibroblasts of other inbred mice.

Animals↗
PubMed1996

[Influence of recirculation type blood cardioplegia on perfusion pressure in open heart surgery].

Infusion blood cardioplegia often decreases the perfusion pressure during open heart surgery. The blood level of bradykinin (BK) was measured in both the cardiopulmonary bypass (CPB) and blood cardioplegia circuit. Infusion cardioplegia with recirculation type circuit increased the BK level of cardioplegia and the perfusion pressure decreased abruptly with the increase BK level in the CPB circuit. In the case of single pass type circuit the BK level was not increased either in cardioplegia or CPB and perfusion pressure was not decreased. We concluded that the single pass type of cardioplegia circuit is superior to the recirculation type because of less production of BK.

Aged↗
PubMed1996

[A case report of mitral valve papillary fibroelastoma leading to embolic stroke].

A 39-year-old man presented with acute onset of left arm and left side face weakness, and mild expressive aphasia. He was referred for two-dimensional echocardiography, which demonstrated a 13 mm diameter pedunculated, mobile, echodense mass attached to the anterior leaflet of the mitral valve. At operation, the tumor was a 10 x 10 x 15 mm, rounded, and yellow-whitish mass with a short stalk arising from rough zone of the anterior leaflet of the mitral valve. The surface appeared to be sean anemone. The mitral valve with this tumor was excised and replaced with a 29 mm St Jude Medical mechanical valve. The pathological findings are typical of a papillary fibroelastoma.

Adult↗
PubMed1996

[Immunohistochemical study of cytokeratin and vimentin expression in mixed type of adenocarcinoma and squamous cell carcinoma].

To clarify the pattern of cytokeratin and vimentin expression in mixed adenocarcinoma and squamous cell carcinoma of the uterine cervix, twenty-three cases of formalin-fixed paraffin-embedded specimen were examined immunohistochemically using a panel of four different monoclonal anti-cytokeratin antibodies and anti-vimentin antibody. Fifty-seven cases of benign or malignant tissue were selected for controls. The results were summarized as follows. 1) In four cases of co-existing adenocarcinoma and squamous cell carcinoma, their immunostaining patterns were compatible with original histological cell type. 2) In four cases of adenoacanthoma, high molecular weight-cytokeratin (HCK) was positive in each acanthomatous component and only a small part of one adenocarcinomatous component. 3) In twelve cases of cervical adenosquamous carcinoma, HCK were positive in four adenocarcinomatous components. Out of eight cases with non-stained adenocarcinomatous components, six cases showed negativity for HCK even in the squamous cell carcinomatous component. 4) Though vimentin was negative in all cases of mixed type of cervical carcinoma, some cases of mixed type endometrial carcinoma were stained positively for vimentin. It was indicated from our study that adenosquamous carcinoma of the cervix could originate either in reserve cells or columunar epithelium and that vimentin positive cases could originate in the endometorial gland.

Adenocarcinoma↗
PubMed1996

Assessment and comparison of algorithms for in vivo ESR-CT imaging of bioradicals with L-band microwaves.

In ESR-CT imaging, it is much more difficult to obtain satisfactory images than in imaging with other modalities, since two inverse problems, i.e. deconvolution of observed data and reconstruction from projections, must be solved. In this work, suitable algorithms for ESR-CT are examined using simulations and experiments. The algorithms were applied to actual data from a rat's head and a satisfactory reconstructed image was obtained from the viewpoint of morphological imaging. Several properties of the algorithms are discussed: (1) which combination of deconvolution and reconstruction method is favorable, (2) whether or not a raw differential signal should be integrated before deconvolution and reconstruction procedures, and (3) how SIRT, which offers good performance in ESR-CT, depends on an initial value and a noise type.

Algorithms↗