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S Ueda

Publications and source records attributed to S Ueda.

At least 37 records · Page 2Linked to original sources
PubMed2003

Radon concentration in indoor occupational environments in Aomori Prefecture, Japan.

The (222)Rn concentrations in indoor workplaces were measured in Aomori Prefecture, Japan, and the results are reported here. This survey was part of a program to measure background natural radiation dose rate in the prefecture where the first Japanese nuclear fuel cycling facilities are now under construction. The survey of the (222)Rn concentrations in indoor workplaces was carried out at 107 locations from 1996 to 1998. The (222)Rn concentrations were measured for approximately one year at each site with passive Rn detectors, which used a polycarbonate film for counting alpha-rays and could separate concentrations of (222)Rn from (220)Rn. Weeklong measurements of (222)Rn concentration and working level were carried out with active detectors to get the ratio of (222)Rn concentration during working hours to non-working hours as well as equilibrium factors in selected locations. Diurnal variation of (222)Rn concentration depended on building structure, air-conditioning, time of day and day of the week (week days or weekend). The (222)Rn concentration during working hours was generally lower than that in non-working hours. Although the annual average (222)Rn concentration in indoor occupational environments was higher than that in dwellings, radiation dose for Aomori Prefecture residents from Rn in the former was 14% of the total indoor dose by Rn because of the lower concentration in working hours and lower occupancy factor.

Air Pollution, Indoor↗
PubMed2003

Postoperative chemotherapy vs chemoradiotherapy for thoracic esophageal cancer: a prospective randomized clinical trial.

BACKGROUND: Neither postoperative radiotherapy nor chemotherapy alone provided a survival benefit after curative esophagectomy for esophageal squamous carcinoma. MATERIAL AND METHODS: Of 103 consecutive patients who underwent potentially curative esophagectomy for esophageal squamous carcinoma, 45 patients with advanced cancers without preoperative adjuvant treatments were prospectively randomized to two groups; postoperative chemotherapy alone (Group A, n=23) and postoperative radio/chemotherapy (Group B, n=22). In Group A, cisplatin (CDDP) (50 mg/m(2)) was given by intravenous infusion on days 1 and 15, and 5-fluorouracil (5-FU) (300 mg/m(2)) was given daily by continuous intravenous infusion for 5 weeks. In Group B, in addition to the same chemotherapeutic regimen of Group A, 50 Gy of radiotherapy was given to the mediastinum over 5 weeks. The immunohistochemical staining of tumoral p53 and microvessel density was undertaken to correlate to the radio/chemosensitivity. RESULTS: There were no significant differences in the clinicopathologic characteristics between the two groups. The median dose of 5-FU and CDDP administered were not significantly different between the two groups. The mean (SD) dose of radiotherapy in Group B was 42+10 Gy. The 1-, 3- and 5-year survival rates in Group A were 100, 63 and 38% and those in Group B were 80, 58 and 50%, respectively (P=0.97). In each group, four patients succumbed to locoregional recurrences. Tumoral p53 was immunohistochemically negative in 43% in Group A and 77% in Group B (P=0.03), indicating that many patients in Group B might be potentially sensitive to radiochemotherapy. The 3- and 5-year survival rates (75 and 64%) of patients with p53 negative expression (n=18) were significantly (P=0.03) better than those with p53 positive expression (n=27, 44 and 26%). The long-term survival was better for patients with p53 negative tumours than those with p53 positive tumours in Group B (P=0.06 by long-rank test, P<0.05 by Generalized-Wilcoxon test). However, the long-term survival was not different between the patients who had p53 negative and positive tumours in Group A (P=0.19). These data suggest that there were no survival advantage for patients receiving radiotherapy in Group B, instead p53 negative tumours appeared to have a favorable prognosis. CONCLUSION: Postoperative radiotherapy administered concurrently with chemotherapy does not provide a survival benefit compared with chemotherapy alone. Tumoral p53 expression has a predictive value for survival in patients treated with postoperative radio/chemotherapy.

Aged↗
PubMed2003

Trazodone hydrochloride attenuates thermal hyperalgesia in a chronic constriction injury rat model.

BACKGROUND AND OBJECTIVE: Trazodone hydrochloride is used in the treatment of neuropathic pain. However, the analgesic effects of trazodone on neuropathic pain are controversial. The study was undertaken to determine the analgesic effect of trazodone on a chronic constriction injury model. METHODS: We tested the effect of trazodone on thermal hyperalgesia due to a chronic constriction injury of the sciatic nerve in rats and examined the effects of lesions in the descending and ascending serotonergic system induced by 5,7-dihydroxytriptamine (5,7-DHT). RESULTS: The analgesic effects of trazodone showed a clear dose dependency. Furthermore, the analgesic effect of trazodone was observed in rats injected with 5,7-DHT into the dorsal raphe nucleus and medial raphe nucleus. CONCLUSIONS: The results suggest that a mainly serotonergic descending pain control pathway mediates the analgesic effects of trazodone.

Animals↗
PubMed2003

Acrolein produced from polyamines as one of the uraemic toxins.

It is well known that the addition of spermine or spermidine to culture medium containing ruminant serum inhibits cellular proliferation. This effect is caused by the products of oxidation of polyamines that are generated by serum amine oxidase. Among the products, we found that acrolein is a major toxic compound produced from spermine and spermidine by amine oxidase. We then analysed the level of polyamines (putrescine, spermidine and spermine) and amine oxidase activity in plasma of patients with chronic renal failure. It was found that the levels of putrescine and the amine oxidase activity were increased, whereas spermidine and spermine were decreased in plasma of patients with chronic renal failure. The levels of free and protein-conjugated acrolein were also increased in plasma of patients with chronic renal failure. An increase in putrescine, amine oxidase and acrolein in plasma was observed in all cases such as diabetic nephropathy, chronic glomerulonephritis and nephrosclerosis. These results suggest that acrolein is produced during the early stage of nephritis through kidney damage and also during uraemia through accumulation of polyamines in blood due to the decrease in their excretion into urine.

Acrolein↗
PubMed2003

Chemical peeling with salicylic acid in polyethylene glycol vehicle suppresses skin tumour development in hairless mice.

BACKGROUND: Chemical peeling with salicylic acid in polyethylene glycol (PEG) vehicle is used clinically to improve the cosmetic appearance of skin that has been damaged by exposure to the sun. It is well known that cancers of the skin such as basal cell carcinoma and squamous cell carcinoma may be induced by the sun. However, the carcinogenic potential of chemical peeling agents has not been studied. OBJECTIVES: To evaluate the effects of chemical peeling with 30% salicylic acid in PEG on skin tumour formation in treated vs. control mice. METHODS: To serve as a model of sun-damaged skin, hairless SKH/hr1 mice were irradiated with ultraviolet (UV) B for 14 weeks, with or without treatment every 2 weeks with 30% salicylic acid in PEG for a total of 18 weeks. RESULTS: Not only was the total number of tumours greatly reduced in the treated vs. the control mice, but skin tumour development was also slower in the treated vs. the control mice. At the final treatment, the fractions of T and B lymphocytes and natural killer cells from spleens of both groups of mice were comparable, and interferon-gamma production did not differ. CONCLUSIONS: Our findings suggest that chemical peeling with salicylic acid in PEG may help to prevent as well as to reduce the number of UVB-induced skin tumours.

Animals↗
PubMed2003

Oncogenic receptor tyrosine kinase in leukemia.

Growth, survival and differentiation of hematopoietic cells are regulated by the interaction between hematopoietic growth factors and their receptors. While the defect in this interaction results in an insufficient hematopoiesis, the aberrantly elevated activation leads to the transformation of hematopoietic cells. The constitutive active mutations of receptor tyrosine kinase, such as c-Kit platelet-derived growth factor receptor (PDGFR) or fins-like tyrosine kinase 3 (Flt3), play a major role in the development of hematopoietic neoplasia. The constitutive activation is provoked by several mechanisms, such as making fusion genes by chromosomal translocations, or various mutations involving regulatory regions of the receptor. The chromosomal translocation brings the receptor intracytoplasmic domain juxtaposed to an unrelated molecule which has dimerization or multimerization motif, resulting in the constitutive dimerization of the receptor. The missense, insertion or deletion mutations in the regulatory regions, such as juxtamembrane domain, activation loop and extracellular domain, cause constitutive activation by releasing the respective auto-inhibitory functions of each regulatory region. Constitutive active receptors generate different signals quantitatively and qualitatively from wild type receptor, which mediate the oncogenic phenotype. Given the frequent involvement of constitutive active receptor tyrosine kinase in hematopoietic malignancies, targeted inhibitions of active tyrosine kinase and downstream aberrant signaling are rapidly developing novel therapeutic modality with much promise.

Animals↗
PubMed2001

Ectopic expression of Smad7 inhibits transforming growth factor-beta responses in vascular smooth muscle cells.

Vascular injury stimulates the cytokine-growth factor network in the vascular wall, including transforming growth factor-beta (TGF-beta). Reportedly, the intracellular signaling of TGF-beta is mediated by Smad proteins. We tested the effects of the ectopic expression of inhibitory Smads in cultured rat smooth muscle cells (SMC) to identify the role of TGF-beta/Smad signaling on the phenotypic modulation of SMC. The cells exposed to human recombinant TGF-beta1 (10 ng/ml) were stimulated Smad2 phosphorylation. Infection with the replication-deficient adenovirus vector expressing Smad7, but not bacterial beta-galactosidase or Smad6, was found to inhibit TGF-beta-induced Smad2 phosphorylation in a dose-dependent manner. TGF-beta suppressed the serum-induced proliferation of SMC from 36.3% to 51.0% (p<0.01), as measured by hand-counting, and this inhibition was attenuated by the ectopic expression of Smad7 (from 30.7% to 74.8% of the reduction of TGF-beta-response, p<0.05), but not Smad6. A BrdU incorporation assay also showed that TGF-beta-mediated growth inhibition was attenuated by exogenous Smad7 and that this inhibition can be reversed by an additional expression of exogenous Smad2. TGF-beta increased the expression of alpha-smooth muscle actin and myosin heavy chain by 1.3-fold and 1.6-fold in comparison to the control, respectively, and these increases were attenuated by exogenous Smad7, but not Smad6. Our data indicate that Smads mediate TGF-beta responses on SMC phenotypes. Smad7, but not Smad6, may specifically act as an inhibitor of TGF-beta responses.

Animals↗
PubMed2001

A role for frequenin, a Ca2+-binding protein, as a regulator of Kv4 K+-currents.

Frequenin, a Ca(2+)-binding protein, has previously been implicated in the regulation of neurotransmission, possibly by affecting ion channel function. Here, we provide direct evidence that frequenin is a potent and specific modulator of Kv4 channels, the principal molecular components of subthreshold activating A-type K(+) currents. Frequenin increases Kv4.2 current amplitudes (partly by enhancing surface expression of Kv4.2 proteins) and it slows the inactivation time course in a Ca(2+)-dependent manner. It also accelerates recovery from inactivation. Closely related Ca(2+)-binding proteins, such as neurocalcin and visinin-like protein (VILIP)-1 have no such effects. Specificity for Kv4 currents is suggested because frequenin does not modulate Kv1.4 or Kv3.4 currents. Frequenin has negligible effects on Kv4.1 current inactivation time course. By using chimeras made from Kv4.2 and Kv4.1 subunits, we determined that the differential effects of frequenin are mediated by means of the Kv4 N terminus. Immunohistochemical analysis demonstrates that frequenin and Kv4.2 channel proteins are coexpressed in similar neuronal populations and have overlapping subcellular localizations in brain. Coimmunoprecipitation experiments demonstrate that a physical interaction occurs between these two proteins in brain membranes. Together, our data provide strong support for the concept that frequenin may be an important Ca(2+)-sensitive regulatory component of native A-type K(+) currents.

Animals↗
PubMed2001

The effect of nitric oxide on acetylcholine release in the rabbit bladder.

We evaluated the effects of nitric oxide (NO) on acetylcholine release and the contractile response induced by electrical field stimulation in rabbit bladder smooth muscles using a muscle bath and high performance liquid chromatography coupled with microdialysis. Electrical field stimulation (supramaximum voltage, pulse duration 0.5 ms, frequency 5 and 20 Hz) was applied to a smooth muscle strip isolated from rabbit bladder. With low-frequency (5 Hz) stimulation, pretreatment with Nomega-nitro-L-arginine (L-NNA) (100 microM) significantly increased electrical field stimulation-induced acetylcholine release and contractile response, which were reduced by the addition of L-arginine. Pretreatment with sodium nitroprusside in the absence or presence of L-NNA significantly decreased electrical field stimulation-induced acetylcholine release and contractile response. In contrast, with high frequency (20 Hz) stimulation, pretreatment with L-NNA and sodium nitroprusside had no significant effect on either contractile response or acetylcholine release. Pretreatment with sodium nitroprusside caused no significant changes in carbachol and ATP-induced contractile responses. Sodium nitroprusside and L-NNA had no significant effects on the atropine-resistant part of the contraction induced by electrical field stimulation in rabbit bladder smooth muscles. The results suggest that there is a NO-mediated mechanism inhibiting acetylcholine release from cholinergic nerve endings in rabbit bladder, which may contribute to bladder function.

Acetylcholine↗
PubMed2001

Molecular cloning and expression of the cDNA encoding feline granulocyte colony-stimulating factor.

Both genomic DNA and cDNA of the feline granulocyte colony-stimulating factor (G-CSF) gene were cloned from CRFK cells. Southern blot analysis showed that the haploid genome contains a single copy of the G-CSF gene. The RT-PCR analysis of several feline cell lines revealed expression of G-CSF mRNA in response to lipopolysaccharide stimulation. Sequence analysis of genomic and cDNA clones indicated that the intron-exon junction structure is conserved between the human and the feline G-CSF genes. The G-CSF coding region encodes a predicted protein of 195 amino acids including a signal sequence of 21 amino acids. The feline G-CSF amino acid sequence shares a high degree of identity with the canine (90.8%), human (87.4%), ovine (83.9%), bovine (82.8%), porcine (80.5%), murine (70.7%) and rat (66.8%) G-CSF. The feline G-CSF expressed in insect cells using recombinant baculovirus vector was biologically active as measured in a proliferation assay using NFS-60 cells and an induction assay of leukocytes in cats.

Amino Acid Sequence↗
PubMed2001

Overexpression of EC-SOD suppresses endothelial-cell-mediated LDL oxidation.

Reactive oxygen species have been proposed to play important roles in atherosclerosis. To investigate the protective role of extracellular superoxide dismutase (EC-SOD), its inhibition of endothelial-cell-mediated LDL oxidation was examined. We constructed the recombinant adenovirus AxCAEC-SOD expressing human EC-SOD by CAG promoter. Infection of endothelial cells with AxCAEC-SOD resulted in EC-SOD protein secretion in a dose-dependent manner and a decrease of endothelial-cell-derived superoxide production. Moreover, it was proven to coexist with heparan sulfate by immunohistochemical staining. Endothelial-cell-mediated LDL oxidation enhanced by ferric-sodium EDTA was inhibited by 47% in TBARS formation by AxCAEC-SOD infection. In agarose gel electrophoresis, AxCAEC-SOD decreased the negative charge of oxidized LDL by 50% and suppressed fragmentation of apolipoprotein B. These results suggested that human EC-SOD localized in the extracellular space and reduced endothelial-cell-mediated LDL oxidation. In subendothelial space, EC-SOD bound on heparan sulfate might suppress LDL oxidation through reduction of superoxide anion.

Animals↗
PubMed2001

PhaR, a protein of unknown function conserved among short-chain-length polyhydroxyalkanoic acids producing bacteria, is a DNA-binding protein and represses Paracoccus denitrificans phaP expression in vitro.

A putative regulatory protein, PhaR, which was identified in the polyhydroxyalkanoic acid synthetic locus (phaZCPR) in Paracoccus denitrificans, was investigated. The PhaR protein purified from a recombinant Escherichia coli was estimated to be 22 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, being consistent with the mass calculated from the nucleotide sequence. The molecular mass was determined to be 93 kDa by size-exclusion chromatography, suggesting that the protein formed a tetramer. A gel mobility shift assay showed that PhaR specifically bound to the intergenic region of phaC--phaP. In a cell-free protein synthesis system using E. coli S30 extract, the expression of the phaP gene was repressed by the addition of purified PhaR. These results suggest that PhaR is a DNA-binding protein and may play a role in the regulation of phaP gene expression.

Bacterial Proteins↗
PubMed2001

Epidermal growth factor stimulation of the ACK1/Dbl pathway in a Cdc42 and Grb2-dependent manner.

The tyrosine kinase ACK1 phosphorylates and activates the guanine nucleotide exchange factor Dbl, which in turn directs the Rho family GTP-binding proteins. However, the regulatory mechanism of ACK1/Dbl signaling in response to extracellular stimuli remains poorly understood. Here we describe that epidermal growth factor stimulates the ACK1/Dbl pathway, leading to actin cytoskeletal rearrangements. The role of the two ACK1-binding proteins Cdc42 and Grb2 was assessed by overexpression of the Cdc42/Rac interactive binding domain and a dominant-negative Grb2 mutant, respectively. Specific inhibition of the interaction of ACK1 with Cdc42 or Grb2 by the use of these constructs diminished tyrosine phosphorylation of both ACK1 and Dbl in response to EGF. Therefore, the activation of ACK1 and subsequent downstream signaling require both Cdc42-dependent and Grb2-dependent processes within the cell. In addition, we show that EGF transiently induces formation of the focal complex and stress fibers when ACK1 was ectopically expressed. The induction of these structures was totally sensitive to the action of botulinum toxin C from Clostridium botulinum, suggesting a pivotal role of Rho. These results provide evidence that ACK1 acts as a mediator of EGF signals to Rho family GTP-binding proteins through phosphorylation and activation of GEFs such as Dbl.

Actins↗
PubMed2001

Polyamine cytotoxicity in the presence of bovine serum amine oxidase.

The toxicity of extracellular spermine, determined in the presence of fetal calf serum, was studied using three cell lines: FM3A, L1210, and NIH3T3 cells. Amine oxidase in fetal calf serum produces aminodialdehyde generating acrolein spontaneously, H(2)O(2), and ammonia from spermine. Spermine toxicity was prevented by aldehyde dehydrogenase, but not by catalase. Similar concentrations of spermine and acrolein were needed to produce toxicity. Other aldehydes (formaldehyde, acetaldehyde, and propionaldehyde) and hydrogen peroxide were less toxic than acrolein. Spermidine and 3-aminopropanal, which produces acrolein, also exhibited severe cytotoxicity. The degree of cytotoxicity of spermine, spermidine, and 3-aminopropanal was nearly parallel with the amount of acrolein produced from each compound. Thus, it was deduced that acrolein is a major toxic compound produced from polyamines (spermine and spermidine) by amine oxidase.

3T3 Cells↗
PubMed2001

Identification of the intracellular polyhydroxyalkanoate depolymerase gene of Paracoccus denitrificans and some properties of the gene product.

Paracoccus denitrificans degraded poly(3-hydroxybutyrate) (PHB) in the cells under carbon source starvation. Intracellular poly(3-hydroxyalkanoate) (PHA) depolymerase gene (phaZ) was identified near the PHA synthase gene (phaC) of P. denitrificans. Cell extract of Escherichia coli carrying lacZ--phaZ fusion gene degraded protease-treated PHB granules. Reaction products were thought to be mainly D(--)-3-hydroxybutyrate (3HB) dimer and 3HB oligomer. Diisopropylfluorophosphonate and Triton X-100 exhibited an inhibitory effect on the degradation of PHB granules. When cell extract of the recombinant E. coli was used, Mg(2+) ion inhibited PHB degradation. However, the inhibitory effect by Mg(2+) ion was not observed using the cell extract of P. denitrificans.

Amino Acid Sequence↗
PubMed2001

Structure-activity relationship of mycoloyl glycolipids derived from Rhodococcus sp. 4306.

Novel mycoloyl glycolipids with short carbon chains were isolated and purified from Rhodococcus sp. 4306, a soil origin of Actinomycetales. Their chemical structures were identified as trehalose 6,6'-dimycolate (TDM), trehalose 6-monomycolate, glucose 6-monomycolate, mannose 6-monomycolate and fructose 6-monomycolate. The length of carbon chains and number of double bonds of mycolic acids were C(34), C(36)and C(38)saturated, monoenoic and dienoic molecular species, which were much shorter than those of Mycobacterium tuberculosis (C(78-88)monoenoic and dienoic). Among them, only TDM could induce prominent granulomatous inflammation of the lung and spleen in mice. By contrast, other mycoloyl glycolipids induced mild lesions. The small-sized TDM of Rhodococcus possessed granulomatogenic activity, however, the toxicity was much lower than that of M. tuberculosis. Rhodococcal TDM was composed of mycolic acid with the shortest carbon chains, when compared to granulomatogenic TDM of Mycobacterium, Nocardia and Rhodococcus reported previously. Our results imply that rhodococcal TDM is a pathogenetic factor similar to that of M. tuberculosis, although rhodococcal TDM exhibits low toxicity.

Actinomycetales Infections↗
PubMed2001

Dukes' classification as a useful staging system in resectable squamous cell carcinoma of the esophagus.

Dukes' classification for colorectal cancer is simple and has been widely used as a valuable prognostic indicator. It has been used as an assessment of gastric cancer, but it has not been evaluated for esophageal cancer. Of 251 patients with primary squamous cell carcinoma of the thoracic esophagus between February 1981 and April 1999, 155 patients underwent esophagectomy with a curative intent. Clinicopathologic characteristics of those 155 patients were retrospectively investigated according to the Dukes', tumor node metastasis (TNM) and Japanese staging systems. Dukes' classification showed a clear correlation between tumor stage and survival. The 3-year and 5-year survival rates of 64 Dukes' A cases were excellent (97.4% and 93.7%), good for 12 Dukes' B (75% and 75%), and poor for 79 Dukes' C (50.5% and 43.4%), respectively (P < 0.05; Dukes' A vs B, P < 0.0001; Dukes' A vs C, P < 0.10; Dukes' B vs C). TNM stage classification also showed a good correlation between tumor stage and survival, but there were no significant differences between stage 0, I and stage IIA cases (P = 0.2678) and between stage III and stage IV cases (P = 0.8298). In the Japanese staging system, there were no significant differences among stage 0, stage 1, and stage 2 cases (P = 0.4093). Dukes' classification was significantly correlated with tumor size, Borrmann type, histological type, and vessel invasion. Subdivision of Dukes' C according to the number of positive lymph nodes (1-4 vs > or = 5) showed a clearer correlation with survival rather than other subdivisions, such as the metastatic lymph node ratio (< 1.0 vs > 1.0) or the site of lymph node metastasis. Dukes' classification, which incorporates the number of positive lymph nodes, correlates well with tumor progression and provides a simple useful staging system after curative esophagectomy for esophageal cancer. Dukes' A tumor could be proposed as a criterion of early esophageal carcinoma.

Aged↗