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T Hamada

Publications and source records attributed to T Hamada.

At least 253 records · Page 14Linked to original sources
PubMed1997

[Epidural anesthesia reduces mortality rate in the patients after emergency abdominal surgery].

Stress response and increased sympathetic stimulation constrict gastrointestinal blood vessels. In patients after abdominal surgery, anastomotic leakage and bacterial translocation may occur as a result of gastrointestinal hypoperfusion. These patients are at risk for severe SIRS and MOF, especially after emergency surgery. Epidural anesthesia decreases sympathetic stimulation and accordingly increases gastrointestinal blood flow. The purpose of this study was to test the hypothesis that epidural anesthesia has a beneficial effect on patients after emergency abdominal surgery. Seventy-seven patients older than 50 years of age having undergone emergency abdominal surgery were studied. Thirty-nine patients received general anesthesia alone (GA) and 38 patients received epidural anesthesia (EA). The data on APACHE II score, fluid intake and output management, mortality rate, and others of the subjects were collected from patient charts. The mortality rate 3 months after surgery in group GA (35.9%) was significantly higher than that in group EA (5.3%) (P < 0.01). There was no difference in APACHE II score and age. Fluid intake was significantly larger in group EA. To reduce mortality rate, epidural anesthesia and volume expansion are recommended for patients after emergency abdominal surgery.

Abdomen↗
PubMed1996

Adenosine A1-receptor agonist attenuates the light-induced phase shifts and fos expression in vivo and optic nerve stimulation-evoked field potentials in the suprachiasmatic nucleus in vitro.

Adenosine is widely accepted to act as an inhibitory neuromodulator in the mammalian central nervous system. In the present study, we examined whether adenosine receptor agonist modifies the photic entraining responses in the rat suprachiasmatic nucleus both in vivo and in vitro. Light (200 lux, 15 min)-induced phase shifts of hamster wheel-running rhythms was attenuated by a systemic administration of A1-adenosine receptor agonist N6-cyclohexyladenosine (N-CHA) in a dose-dependent manner; 0.5 mg/kg N-CHA caused 60% inhibition of light-induced phase shifts. On the other hand, A2-adenosine receptor agonist N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)-ethyl]adenosine (DPMA) failed to inhibit light-induced phase shifts. Systemic administration of N-CHA but not of DPMA inhibited light (300 lux, 1 h)-induced Fos expression in the suprachiasmatic nucleus in a dose-dependent manner; 1 mg/kg N-CHA caused 73% inhibition of light-induced Fos expression. Bath application of N-CHA but not of DPMA inhibited optic nerve stimulation-evoked field potentials in rat suprachiasmatic nucleus slices. The present results suggest that activation of adenosine A1-receptor attenuates the photic input through the inhibition of retinohypotalamic pathway to the SCN.

Adenosine↗
PubMed1996

Characterization of novel secreted and membrane proteins isolated by the signal sequence trap method.

We recently described a method, called the signal sequence trap (SST) method, to clone cDNAs of secreted proteins and/or type I transmembrane proteins containing N-terminal signal sequences by using an epitope-tagging expression plasmid vector. In this paper we describe the summary of a large-scale screening of approximately 5900 clones of an SST cDNA library constructed from mouse bone marrow stromal cell line ST-2 cells. Of 26 positive clones obtained and sequenced, 11 clones appeared to contain authentic signal sequences. Five of the clones corresponded to the 5' ends of the cDNA of known genes containing N-terminal signal sequences. The full-length cDNA clones of the 6 other unknown clones were isolated and sequenced. One clone, termed SDF3, encoded a mouse counterpart of human pigment epithelium-derived factor. Another clone, termed SDR1, had considerable homology with basigin, a member of the immunoglobulin superfamily. A third clone, termed SDF5, had partial homology with a Drosophila tissue polarity gene frizzled (fz) and its rat homologues, fz-1 and fz-2. The other three clones had no significant homology with sequences in the databases. These results indicate that the SST method is effective and useful for the isolation of secreted and membrane proteins without knowledge of their functions.

Amino Acid Sequence↗
PubMed1996

Isolation and characterization of a novel secretory protein, stromal cell-derived factor-2 (SDF-2) using the signal sequence trap method.

With use of the signal sequence trap method, we isolated a cDNA encoding a novel secretory protein, SDF-2, from the mouse stromal cell line, ST2. The human homologue of SDF-2 was also isolated. The amino acid (aa) sequences deduced from both the clones were conserved more than 92%. The chromosomal localization of the human SDF-2 gene was mapped to 17q11.2. The aa sequence of SDF-2 shows similarity to those of yeast dolichyl phosphate-D-mannose:protein mannosyltransferases, Pmt1p [Strahl-Bolsinger et al. (1993) Proc. Natl. Acad. Sci. USA 90, 8164-8168] and Pmt2p [Lussier et al. (1995) J. Biol. Chem. 270, 2770-2775], whose activities have not been detected in higher eukaryotes.

Amino Acid Sequence↗
PubMed1996

Experimental liver fibrosis induced in rats receiving high doses of alcohol and alternating between regular and vitamin-depleted diets.

Liver fibrosis was induced in rats by simulating human alcoholic eating and drinking patterns. Alcohol addiction was established by gradually increasing the ethanol concentration in the drinking water; salts were added at the terminal stage. The hepatocytes of rats receiving alcohol concentrations exceeding 50% (v/v) (similar to vodka) exhibited alcoholic hyaline (Mallory bodies). Alcoholic liver fibrosis was induced by alternating between regular and autoclaved (vitamin-depleted) diets, simulating the irregular eating habits of human alcoholics. In the livers of rats receiving 70% (v/v) ethanol (comparable to absinthe) with 25% saline and fed the alternating diets, pericellular fibrosis was induced. No significant difference in calorie intake between control and alcohol rats was detected except when rats underwent drinking bouts (heavy drinking phase). This indicates that neither a high-fat diet nor a choline-depleted diet is necessary to induce the alcoholic fibrosis seen in human alcoholics.

Animals↗
PubMed1996

A model for development of Gabor-receptive fields in simple cortical cells.

A model is proposed for the development of Gabor-like receptive fields of simple cells in the visual cortex. We assume that several cortical cells are arranged in a ring, with mutual excitatory or inhibitory connections of fixed weight. The cells also receive excitatory synapses from LGN; the synaptic weights are initially set random and then modified based on correlated dark activity in LGN. Each cell finally acquires a simple receptive field best described by a Gabor function. Spatial phase in the function varies regularly from 0 to 2 pi with rotation along the ring.

Geniculate Bodies↗
PubMed1996

Apoptosis of human kidney 293 cells is promoted by polymerized cadmium-metallothionein.

Transformed human kidney cells (293 cells) exposed to 12.5 to 37.5 microM CdCl(2) showed apoptosis as confirmed by characteristic electron microscopic features, a ladder on gel electrophoresis of extracted DNA, and fragmentation of nucleosomes as detected by enzyme linked immunosorbent assay (ELISA). Higher concentrations of Cd were less effective in inducing apoptosis. Furthermore, addition of the protein extract from the serum-free medium used for Cd-exposure promoted apoptosis exhibiting the same features as that after Cd-exposure. The apoptosis induced by the protein was dose-dependent. The molecular weight of the protein (Cd-protein) was shown to be 40 kDa by gel filtration. Two-dimensional electrophoresis revealed the Cd-protein as a single spot with a molecular weight of 6 kDa and pI of 4.5. Competitive ELISA showed that the Cd-protein reacted with anti-metallothionein antibody. The present findings suggest that apoptosis is induced not only by Cd itself but also by polymerized metallothionein molecules (MT) released from cells into the medium.

Animals↗
PubMed1996

Modification of fatty acid composition by over- and antisense-expression of a microsomal omega-3 fatty acid desaturase gene in transgenic tobacco.

omega-3 fatty acid desaturases, which catalyse the conversion of linoleic acid (18:2) to linolenic acid (18:3) in lipids, are located in the microsomes and plastid membranes. Transgenic tobacco plants were produced that express the transcripts of a tobacco microsomal omega-3 fatty acid desaturase gene (NtFad3) in antisense and sense orientations under the control of the cauliflower mosaic virus 35S promoter. The antisense construct has the 0.5-kb fragment of the NtFad3 cDNA containing a 3'-flanking region and a part of the coding region in antisense orientation. The antisense-transformant lines showed decreases of the steady-state NtFad3 mRNA level to 30% of the control plants. In these lines, the 18:3 content decreased to about 80% in root tissues and to about 70-80% in leaf tissues when compared with the control plants. The sense construct has the 1.4-kb full-length cDNA of NtFad3. In one of the sense-transformant lines, the NtFad3 mRNA level increased 8 times when compared with that of the control plants. In this line, the 18:3 content increased by about 1.5-fold in root tissues and by about 1.1-fold in leaf tissues. These results indicate that the up- and down-regulation of the transcript level in the microsomal omega-3 fatty acid desaturase gene is useful to modify the 18:3 content in the vegetative tissues of higher plants.

Antisense Elements (Genetics)↗
PubMed1996

Detection of lysyl oxidase gene expression in rat skin during wound healing.

Lysyl oxidase (LOX) initiates the crosslinking of the lysine-derived aldehyde and plays an essential role in maturation of collagen, for example in wound healing. Although the activity of this enzyme has been examined in various disorders, and a further intriguing aspect of the relationship between LOX and tumorigenesis has recently emerged, its gene expression pattern in tissues is still unknown. We examined LOX gene expression during wound healing in rat skin. In addition, type III collagen gene expression was studied to determine the formation of fibrils. The LOX mRNA level reached a peak by day 3 after injury, which was earlier than that of type III collagen, and continued at a high level until day 22. The type III collagen mRNA level began to rise from day 3 and had increased intensely by day 22. In situ hybridization revealed grains corresponding to LOX mRNA in the fibroblasts of the granulomatous tissue. These results suggest that LOX is produced before collagen synthesis in preparation for crosslinking in the early phase of wound healing.

Animals↗
PubMed1996

Benign fibrous histiocytoma of the femur: review of three cases.

OBJECTIVE: Benign fibrous histiocytoma is a tumor with histologic features similar to those of xanthofibromas, which include fibrous cortical defects and nonossifying fibromas, but with different clinical features. This study investigated the findings of benign fibrous histiocytoma on various imaging modalities. It emphasized the importance of clinical and imaging features as well as histologic findings in establishing the diagnosis. DESIGN: We reviewed three cases of benign fibrous histiocytoma of the femur that had been diagnosed histologically as (fibro)xanthoma during a retrospective analysis of 187 primary benign and malignant bone lesions. PATIENTS: All the patients were middle-aged women with various knee complaints. RESULTS AND CONCLUSIONS: Radiologically, the lesions were all lytic with well-defined geographic margins and sclerotic rims. The tumors arose within the medullary cavity in the distal metaphysis of the femur and involved the epiphysis. CT showed lytic destruction with well-defined marginal sclerosis. T1-weighted MR images showed that the lesions had predominantly the same signal intensity as that of skeletal muscle. The lesions were hypovascular on angiography. Bone scintigraphy showed moderately increased uptake. It was concluded that multiple images as well as clinical features can be useful in differentiating benign fibrous histiocytoma from fibroxanthoma, giant cell tumor, and other fibrohistiocytic tumors of bone.

Aged↗
PubMed1996

Butylated hydroxyanisole blocks the inhibitory effects of tumor necrosis factor-alpha on collagen production in human dermal fibroblasts.

Tumor necrosis factor-alpha (TNF-alpha) has been demonstrated to selectively decrease the production of type I and type III collagens in human dermal fibroblasts. The effects of the commonly used food antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol, propyl gallate, superoxide dismutase (SOD), and catalase on TNF-alpha-induced growth enhancement and collagen metabolism were evaluated in the present study. BHA at concentrations of both 5 x 10(-5) and 10(-4) M inhibited cell proliferation and DNA synthesis induced by 10 ng/ml TNF-alpha in human dermal fibroblasts, while other antioxidants had minimal effects. Further, BHA (5 x 10(-5) M and 10(-4) M) significantly blocked TNF-alpha-induced decreases in collagen synthesis. These results suggest that antioxidants such as BHA may be involved in the modulation of collagen synthesis by TNF-alpha in human dermal fibroblasts.

Antioxidants↗
PubMed1996

Phytochrome regulates phosphorylation of a protein with characteristics of a nucleoside diphosphate kinase in the crude membrane fraction from stem sections of etiolated pea seedlings.

The molecular mechanism of light signal perception via phytochrome was analysed using the third internodes of etiolated pea seedlings irradiated with red or red followed by far-red light. A crude membrane fraction prepared from the tissue was labelled by [gamma-32P]ATP at 4 x 10(-8) M for 15 s at 0 degree C, and the proteins were separated by two-dimensional gel electrophoresis. The phosphorylation of a protein with a molecular mass of about 15 kDa in the crude membrane fraction increased with an increase in the intensity of red light irradiation (10, 50 and 100 mumol m-2 s-1) for 20 s. Successive irradiation with red light (100 mumol m-2 s-1 for 20 s) and subsequent irradiation with far-red light reduced the phosphorylation of the protein, depending on the intensity of the far-red light (from 0.1 to 8 mumol m-2 s-1 for 180 s). A plasma membrane purified from the crude membrane fraction from red light irradiated tissue showed a rapid phosphorylation of the 15 kDa protein by 4 x 10(-8) M [gamma-32P]ATP at 0 degree C for 7 s, and subsequent addition of ATP, GTP, ADP or GDP at 10(-5) or 10(-6) M efficiently removed the phosphoryl group of the 15 kDa protein. The 15 kDa protein was autophosphorylated in the gel following separation by sodium dodecylsulphate (SDS) polyacrylamide gel electrophoresis. The partially purified 15 kDa protein included nucleoside diphosphate kinase (NDP kinase) activity, as well as cross-reactivity with an antibody specific to rat NDP kinase as assayed by immunostaining and crossreactivity with an antibody specific to ricet NDP kinase as assayed by immunoprecipitation.

Animals↗
PubMed1996

Composition and effect of denture base resin surface primers for reline acrylic resins.

This study investigated the effect of resin surface primers for reline acrylic resins on the surface texture of denture base resin by use of scanning electron microscopy. Analysis of the composition of the primers was also conducted. The composition of the primers was classified into three groups: solvent based, monomer based, and monomer and polymer based. Scanning electron microscopic observation revealed various effects of the primers on the denture base resin surface, which depended on the composition of primers.

Acetone↗