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Biomedical subjects

T Tsuchida

Publications and source records attributed to T Tsuchida.

At least 145 records · Page 8Linked to original sources
PubMed1997

Epoxyquinomicins A, B, C and D, new antibiotics from Amycolatopsis. I. Taxonomy, fermentation, isolation and antimicrobial activities.

A new structural class of the antibiotic, epoxyquinomicins A, B, C and D were isolated from the culture broth of the strain MK299-95F4, which was related to Amycolatopsis sulphurea. Antimicrobial activity of epoxyquinomicins A and B were weak against Gram-positive bacteria, and epoxyquinomicins C and D showed almost no antimicrobial activity and no cytotoxicity. All these antibiotics showed improvement of collagen induced arthritis in vivo.

Actinobacteria↗
PubMed1997

Epoxyquinomicins A, B, C and D, new antibiotics from Amycolatopsis. III. Physico-chemical properties and structure determination.

The structures of epoxyquinomicins A (1), B (2), C (3) and D (4) were determined by spectroscopic studies. Compound 1 was determined to be (5R,6S)-2-(3-chloro-2-hydroxybenzoylamino)-5-hydroxymethyl-5,6-epo xy- 2-cyclohexene-1,4-dione. Compound 2 was revealed to be the dechlorinated derivative of 1. Compounds 3 and 4 were determined to be the reduced derivative of 2 and 1, respectively.

Actinobacteria↗
PubMed1997

Quantification of regional cerebral blood flow with continuous infusion of technetium-99m-ethyl cysteinate dimer.

UNLABELLED: We propose a new method to quantify regional cerebral blood flow (rCBF) with continuous infusion of 99mTc-ethyl cysteinate dimer (ECD) and dynamic SPECT. METHODS: Thirteen subjects were studied. Seven subjects had SPECT and PET studies, and the other six subjects were involved in the measurement of blood clearance of 99mTc-ECD. During constant infusion of 99mTc-ECD (740 MBq) over 10 min, dynamic SPECT scans were obtained every 1 min by means of a triple-head rotating SPECT camera. Intermittent arterial blood sampling with octanol extraction was performed every 1 min to estimate the arterial input function. Influx constant (Ku) obtained by Gjedde-Patlak graphical plot method was compared with rCBF measured by PET using 15O CO2 steady state method. In order to simplify the procedure, arterial input function in each subject was estimated by calibration of the arterial blood sampled at the end of the scan to the standard arterial input function estimated from the blood clearance rate in six subjects. RESULTS: Ku was linearly correlated with rCBF (Ku = 0.09 + 0.62 rCBF, r = 0.85, p < 0.05). Ku calculated with the estimated input function (Ku') and rCBF also demonstrated a linear relationship (Ku' = 0.05 + 0.65 rCBF, r = 0.84, p < 0.05). CONCLUSION: The proposed method with one-point arterial sampling is a simple, clinically feasible tool for quantitative measurement of rCBF with 99mTc-ECD.

Adult↗
PubMed1997

Recovery of perfusion, glucose utilization and fatty acid utilization in stunned myocardium.

We describe the clinical features and results of cardiac catheterization, PET ([13N]ammonia, 18F-fluorodeoxyglucose (FDG)) and SPECT [123I-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP)], in a patient with acute myocardial infarction successfully treated with intracoronary thrombolytic therapy. We compared the clinical and electrocardiographic changes with the myocardial glucose and fatty acid metabolism in stunned myocardium over a period of several months. The patient we studied illustrates the features of stunned myocardium. In the subacute phase, there was a concordant depression of myocardial [13N]ammonia and FDG uptake, and the metabolic abnormalities persisted even after regional wall motion at rest had returned to normal. The electrocardiographic recovery of deep negative T waves appeared to be related to the metabolic recovery in regions of stunned myocardium in this patient.

Ammonia↗
PubMed1996

Simplified quantification of regional cerebral blood flow with 99mTc-ECD SPECT and continuous arterial blood sampling.

The goal of this study was to develop a simple method for quantification of regional cerebral blood flow (rCBF) with 99mTc-ethyl cysteinate dimer (ECD) SPECT. Following an intravenous constant infusion of ECD for one minute, serial dynamic SPECT imaging was performed for 40 minutes in 6 healthy male volunteers with intermittent arterial blood sampling. PET scan with 15O-water was performed on the same day before the SPECT study for measurement of rCBF. Arterial blood data demonstrated rapid conversion of ECD to the hydrophilic metabolites, and most of the arterial input to the brain was completed within 5 minutes after the injection. Brain activity reached a peak value soon after the cessation of infusion, and was stable thereafter with very little washout. Net extraction of ECD in the brain calculated by arterial input of ECD and rCBF demonstrated a rapid decrease within a few minutes, reaching 42.7% at 5 minutes. The simulation study suggested that the arterial blood activity obtained by continuous drawing for 5 minutes and a single SPECT scan would provide a reasonable estimate of rCBF under the assumption of constant net extraction in the brain.

Adult↗
PubMed1996

Neuronal and glial characteristics of central neurocytoma: electron microscopical analysis of two cases.

We have identified two central neurocytomas which contained cells co-expressing glial fibrillary acidic protein and synaptophysin defined by double-label immunostaining. Dual-positive cells were mostly polygonal in shape and with a morphological appearance similar to that of reactive astrocytes. This distinct morphology could be used to distinguish cells expressing glial fibrillary acidic protein from cells with round and clear cytoplasm which did not express glial fibrillary acidic protein and which composed the majority of the tumor. Samples containing polygonal cells were selected for electron microscopy from toluidine blue-stained semithin sections. Ultrastructural findings were similar in both neurocytomas, with both being composed predominantly of round cells with clear cytoplasm corresponding to the clear cells identified by light microscopy. Dense-core vesicles and clear vesicles were frequently observed in the cell processes. Apart from these clear cells, polygonal cells with electron-dense cytoplasm were noted. Paralleling the result of double immunostaining, these polygonal cells contained both dense-core vesicles and intermediate, presumably glial filaments. Microtubules and lipofuscin granules were also observed. These results suggest that cells expressing glial fibrillary acidic protein in central neurocytoma include tumor cells with both neuronal and glial characteristics.

Adult↗
PubMed1996

Vesicle formation in dermatomyositis associated with gynecologic malignancies.

Vesicle formation in dermatomyositis is rare. We describe two women with dermatomyositis and vesicle formation on their extremities. Both had an ovarian cancer and histologic examinations revealing subepidermal vesicles. In both patients, direct immunofluorescence did not reveal deposition of immunoglobulin in the basement membrane zone. Of our two patients and the 17 previously reported to have dermatomyositis with vesicle formation, 10 had an internal malignant disease. Of these 10 patients, eight women had gynecologic malignant disease and two men had gastric cancer and lung cancer, respectively. Vesicle formation in dermatomyositis is strongly related to the presence of an internal malignant process, especially gynecologic malignant disease in female patients.

Dermatomyositis↗
PubMed1996

Testosterone inhibits immunoglobulin production by human peripheral blood mononuclear cells.

We studied the in vitro effect of testosterone on spontaneous immunoglobulin production by human peripheral blood mononuclear cells (PBMC). Testosterone inhibited IgG and IgM production by PBMC both from males and females. The inhibitory effect of testosterone was revealed at doses more than 1 nM, increased dose-dependently, and reached a plateau at 100 nM. At doses < 1000 nM, testosterone did not reduce cell viability. Testosterone treatment reduced IgG production by 59.0% and that of IgM by 61.3% compared with control. Immunoglobulin production by B cells was also suppressed by testosterone, though the magnitude of the suppressive effect on B cells was lower than that on whole PBMC; testosterone-induced decrease of IgG production compared with control was 26.9% and that of IgM was 24.9%. Exogenous IL-6 partially restored the impaired immunoglobulin production of testosterone-treated PBMC; IgG production in testosterone culture was increased by IL-6 from 35.6% to 66.5% of control and that of IgM was also increased from 38.9% to 71.2%, respectively. Testosterone treatment reduced IL-6 production of monocytes by 78.4% compared with control, but neither affected that of T cells or B cells. These results suggest that testosterone may suppress immunoglobulin production of human PBMC directly by inhibiting B cell activity and indirectly by reducing IL-6 production of monocytes. It is thus indicated that this hormone may have protective and therapeutic effects on human autoimmune diseases.

Adult↗
PubMed1996

Clinical features of systemic lupus erythematosus in men. Characteristics of the cutaneous manifestations.

BACKGROUND: Cutaneous manifestations of systemic lupus erythematosus (SLE) in men have not been precisely investigated. OBJECTIVE: The purpose of this study is to define the clinical features of SLE in men, focusing on skin lesions. METHODS: The clinical and laboratory manifestations of 28 male and 111 female patients were compared. RESULTS: Widespread discoid lupus erythematosus (DLE) and papular and nodular mucinosis (PNM) were significantly more common in men than in women. Serum sex hormone levels were within the normal range in all make patients examined. CONCLUSION: This study suggests that gender differences exist in SLE and that male patients tend to present with atypical cutaneous manifestations.

Adolescent↗
PubMed1996

Juvenile temporal arteritis with eosinophilia: a distinct clinicopathological entity.

BACKGROUND: Juvenile temporal arteritis has been proposed as an entity but remains controversial. CASE REPORT: A 39-year-old male, who was otherwise asymptomatic, developed painless bilateral nodules in the temporal areas. His eosinophil blood count was 2,660/mm3 (31%), while the erythrocyte sedimentation rate was normal. Histologic examination of the lesion revealed non-giant-cell granulomatous inflammation with abundant eosinophil infiltration. The clinical and pathologic manifestations in our patient were different from those in classic temporal arteritis, which occurs almost exclusively in individuals over the age of 50 years, allergic granulomatosis and angiitis, and thromboangiitis obliterans. Eight cases of this disease have previously been reported in the literature. CONCLUSION: We consider that 'juvenile temporal arteritis with eosinophilia' is a distinct clinical and pathologic entity. The prognosis of the diseases is considered to be good.

Adult↗
PubMed1996

Heliquinomycin, a new inhibitor of DNA helicase, produced by Streptomyces sp. MJ929-SF2 I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Heliquinomycin was isolated as a part of a program designed to find inhibitors of DNA helicase from microbial sources. It was purified from the culture broth of Streptomyces sp. MJ929-SF2 by solvent extraction and serial chromatographies of centrifugal partition chromatography, Sephadex LH-20 and Capcell Pak C18 (HPLC). The isolated red powder was analyzed to have the molecular formula of C33H30O17. It inhibited partially purified DNA helicase from HeLa cell in a non-competitive manner with the inhibition constant (Ki) of 6.8 mM. Heliquinomycin exhibited biological activity against microorganisms including MRSA, and cultured cell lines.

Animals↗
PubMed1996

[Dynamics of photosensitizer in the cell].

1) Mono-L-aspartyl chlorin e6 is a photosensitizer with a molecular weight of 799.7 in which the double bond porphyrin ring has been reduced and an aspartic acid is attached to the propionic group at the carbon of the tetrapyrole ring via a peptide linkage. 2) The absorption spectrum of mono-L-aspartyl chlorin e6 is characterized by a Soret band at 398 nm and four Q bands located at 502, 530, 620, and 654 nm in PBS solution at pH 7.4. However, when it bound to serum albumin at ratios of more than 1:1 absorption peaks showed a red shift at 6 nm in the PBS solution. 3) Erythrocytes in the blood containing serum albumin and the same concentration of mono-L-aspartyl chlorin e6 were not lysed with the diode laser irradiation. 4) The concentration of mono-L-aspartyl chlorin e6 in mitochondria fraction of normal tissue decreased from 2 hours after intravenous injection. However, the concentration of mono-L-aspartyl chlorin e6 in mitochondria fraction of tumor increased during 4 hours after injection and then gradually decreased.

Animals↗
PubMed1996

Immunohistochemical observation of foci of muscle actin-positive tumor cells in meningiomas.

OBJECTIVE: It has been suggested that muscle actin is expressed in some meningiomas. The purpose of this study was to examine this hypothesis in a large number of meningiomas and to examine possible explanations for this expression. DESIGN: Sixty-five meningiomas were examined using immunohistochemistry for muscle actin. Meningiomas with foci of muscle actin-positive cells (n = 6) were further examined using monoclonal antibodies for desmin, epithelial membrane antigen, cytokeratin, and von Willebrand factor. These specimens were also stained for reticulin. SETTING: All tissues were obtained from surgical biopsy specimens at a large academic medical center. MAIN OUTCOME MEASURES: Meningioma cells were considered to express muscle actin if the expression was shown to localize specifically in meningothelial cells and whorls that were also positive for epithelial membrane antigen. RESULTS: Seventeen of 65 meningiomas were shown to contain muscle actin-positive cells. Scattered cells were positive in 11 cases, and in the remaining six cases we observed foci of muscle actin-positive cells, which had a propensity to form cellular whorls. These foci expressed epithelial membrane antigen, but stains for desmin, cytokeratin, von Willebrand factor, and reticulin were negative. CONCLUSIONS: Our findings suggest that meningioma cells elaborate muscle actin without showing differentiation into specific cell types.

Actins↗