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T Umeda

Publications and source records attributed to T Umeda.

At least 37 records · Page 2Linked to original sources
PubMed2001

Electron spin resonance observation of the Si(111)-(7x7) surface and its oxidation process.

Electron spin resonance (ESR) observation of dangling-bond states on the Si(111)-(7x7) surface is demonstrated for the first time. The ESR spectra clearly show that a reaction of molecular oxygen with the Si(111)-(7x7) surface is associated with the appearance of a new dangling-bond center at unreacted Si adatoms. Most of the oxidized surface sites do not show ESR signals, but in a minor part of the surface another new type of surface defect is detected. The well known P(b) center at the SiO2/Si interface is found to evolve at an oxide thickness as thin as 0.3 nm.

Journal Article↗
PubMed2001

Visualizing synapse formation and remodeling: recent advances in real-time imaging of CNS synapses.

The formation and maintenance of synaptic connections are critical in the development and plasticity of the central nervous system (CNS). Until recently, there have been few studies that followed the molecular sequences of the CNS synapse formation and maintenance. This situation changed dramatically after the introduction of green fluorescent protein (GFP)-based fluorescent probes and the development of lipophilic tracers of endocytotic membranes. These techniques enabled us to visualize presynaptic and postsynaptic structures in living neurons and illustrated active transport and remodeling of synaptic components. Furthermore, recent attempts to identify correlation between presynaptic and postsynaptic morphogenesis suggested very rapid time course of synapse formation at the individual axo-dendritic contact sites. These recent works clearly demonstrated the power of real-time imaging studies. Development of a wide variety of fluorescent probes and advances in the imaging techniques in future will further extend our knowledge on the molecular events that take place in the process of the development and maturation of synaptic junctions.

Animals↗
PubMed2001

Coffee consumption and serum aminotransferases in middle-aged Japanese men.

We investigated the relation between coffee drinking and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations among 7313 Japanese men receiving a health examination, excluding former alcohol drinkers and men with a history of chronic liver disease. Serum AST > 40 and/or ALT > 40 U/L was defined as liver inflammation. Adjustment was made for alcohol use, smoking, body mass index, serum marker for hepatitis virus infection, and other possible confounders. Adjusted odds ratios of liver inflammation were 1.00 (reference), 0.80, 0.69, and 0.61 for men drinking < 1, 1-2, 3-4, and > or = 5 cups of coffee daily, respectively. Among 6898 men without liver inflammation, serum AST and ALT were inversely associated with coffee consumption, and alcohol-related rise in AST was attenuated with coffee drinking. These findings suggest coffee may have an effect of suppressing the rise of serum aminotransferase, partly by inhibiting the alcohol-related elevation. Studies regarding biological mechanism are warranted.

Alanine Transaminase↗
PubMed2001

Proximal-type epithelioid sarcoma: a clinicopathologic study of 20 cases.

We studied the clinicopathologic and immunohistochemical features of 20 cases of proximal-type epithelioid sarcoma to identify prognostic factors. The 20 patients ranged in age from 13 to 80 years (mean, 40 y); 12 patients were male and 8 were female. The tumors presented as deep soft-tissue or subcutaneous masses on the inguinal region in five, the thigh in four, the vulva in three, the axilla in three, and one each in the flank, chest wall, back, hip and perineum. The tumors ranged from 2 to 16 cm at their greatest diameter (mean: 7.8 cm). Histologically, 12 tumors (60%) were classified as the large-cell subtype, characterized by sheets of large cells with prominent nucleoli resembling poorly differentiated carcinoma, and a frequent rhabdoid phenotype, six (30%) were classified as the conventional subtype, and two (10%) as the angiomatoid subtype. The numbers of tumors exhibiting immunoreactivity for various markers were: vimentin (20 cytokeratin (20 [100%]); epithelial membrane antigen (17 [85%]); CD34 (9 [45%]); CD99 (5 [25%]); muscle markers, either desmin or alpha-smooth muscle actin (3 [15%]), other markers such as S-100 protein, neurofilament, neuron-specific enolase, synaptophysin and CD56 (12 [60%]); and p53 (16 [80%]). Fourteen lesions (70%) exhibited an MIB-1 index of 30% or more and, by a system of histologic grading using the MIB-1 score, 16 tumors (80%) were classified as high-grade (Grade 3). Thirteen patients (65%) developed local recurrence and 15 (75%) had metastases, primarily to the lymph nodes. At the last follow-up, 13 patients (65%) had died of their disease. A large tumor size and early metastasis were independently associated with a poor outcome. We conclude that proximal-type epithelioid sarcomas are rare, undifferentiated soft-tissue sarcomas of adults, with epithelioid features and a frequent rhabdoid phenotype. These tumors, when arising in proximal locations, have a much worse prognosis than those arising in distal locations.

Adolescent↗
PubMed2001

Solitary fibrous tumor of renal pelvis.

A 70-year-old Japanese man was referred because of a right renal mass of 2 years in duration. Imaging studies, including magnetic resonance imaging, revealed an ovoid mass, with relatively abundant vascularity, in the right renal pelvis. Right radical nephrectomy was done and a tumor measuring 6.0 x 4.5 x 4.0 cm was found in the renal pelvis. Solitary fibrous tumor (SFT) was highly suspected by histology. Immunohistochemical study using a monoclonal antibody directed against the human hematopoietic progenitor cell antigen (CD34) stain confirmed SFT. This is the first case of SFT of the renal pelvis. Although SFT is extremely rare in urogenital organs, this tumor must be included in the differential diagnosis when we encounter urogenital tumors consisting of mesenchymal elements.

Aged↗
PubMed2001

Effect of sodium butyrate on reactive oxygen species generation by human neutrophils.

BACKGROUND: Short-chain fatty acids enema has been shown to be effective in the treatment of ulcerative colitis (UC). However, the mechanisms that lead to this response have not been well characterized. The aims of this study were to investigate the effect sodium butyrate has on reactive oxygen species (ROS) generation by human neutrophils, which are responsible for mucosal injury. METHODS: Human neutrophils incubated with or without sodium butyrate were stimulated with opsonized zymosan (OZ) or phorbol myristate acetate (PMA). ROS generation was largely differentiated with flow cytometry assays of hydroethidine oxidation and dichlorofluorescein oxidation for superoxide anion and hydrogen peroxide respectively, and luminol-dependent chemiluminescence for myeloperoxidase-mediated oxidants. RESULTS: Sodium butyrate (up to 50 mM) did not alter hydroethidine oxidation upon stimulation of the OZ or PMA. However, sodium butyrate at a concentration of 25 mM elevated dichlorofluorescein oxidation to 125 + 8% (P = 0.028) of control upon stimulation of OZ and to 191 +/- 30% (P = 0.0016) upon stimulation of PMA. Contrary to these results, sodium butyrate greatly inhibited chemiluminescence responses in a dose-dependent manner. The inhibition by 50 mM sodium butyrate was 61 +/- 6% upon OZ and 71 +/- 9% upon PMA, respectively. CONCLUSIONS: These data indicate that sodium butyrate up-regulates hydrogen peroxide generation but down-regulates generation of myeloperoxidase-mediated oxidants, the latter being more potent in killing microorganisms and in inducing tissue injury. A possible mechanism is suggested whereby sodium butyrate may inhibit myeloperoxidase activity and hence attenuate the destructive activities of neutrophils in UC.

Butyrates↗
PubMed2001

Limited proteolysis of filamin is catalyzed by caspase-3 in U937 and Jurkat cells.

Members of the caspase family have been implicated as key mediators of apoptosis in mammalian cells. However, few of their substrates are known to have physiological significance in the apoptotic process. We focused our screening for caspase substrates on cytoskeletal proteins. We found that an actin binding protein, filamin, was cleaved from 280 kDa to 170, 150, and 120 kDa major N-terminal fragments, and 135, 120, and 110 kDa major C-terminal fragments when apoptosis was induced by etoposide in both the human monoblastic leukemia cell line U937, and the human T lymphoblastic cell line Jurkat. The cleavage of filamin was blocked by a cell permeable inhibitor of caspase-3-like protease, Ac-DEVD-cho, but not by an inhibitor of caspase-1-like protease, Ac-YVAD-cho. These results suggest that filamin is cleaved by a caspase-3-like protease. To examine whether caspase-3 cleaves filamin in vitro, we prepared a recombinant active form of caspase-3 directly using a Pichia pastoris overexpression system. When we applied recombinant active caspase-3 to the cell lysate of U937 and Jurkat cells, filamin was cleaved into the same fragments seen in apoptosis-induced cells in vivo. Platelet filamin was also cleaved directly from 280 kDa to 170, 150, and 120 kDa N-terminal fragments, and the cleavage pattern was the same as observed in apoptotic human cells in vivo. These results suggest that filamin is an in vivo substrate of caspase-3.

Antineoplastic Agents↗
PubMed2001

Exercise training and energy restriction decrease neutrophil phagocytic activity in judoists.

PURPOSE: To investigate the effects of weight reduction as the result of exercise training and energy restriction on neutrophil function. METHODS: Eighteen male competitive college judoists participated in the study. In a whole blood assay, oxidative burst activity, phagocytic activity, expressions of Fc gamma receptor 3 (CD16), and complement receptor 3 (CD11b) of neutrophils were measured on a per cell basis by flow cytometry at day 20, 5, and 1 before and at day 7 after the competition. RESULTS: The rate of neutrophil producing reactive oxygen species decreased before the competition, whereas the oxidative burst activity per cell increased significantly in all subjects, which resulted in a significant increase of the total oxidative burst activity. However, there were no significant effect of energy restriction on oxidative burst activity. The rate of neutrophils incorporating opsonized zymosan decreased significantly with energy restriction. The total phagocytic activity of 10,000 neutrophils and the phagocytic activity per cell also decreased significantly by severe energy restriction. The surface antigen expressions of CD11b and CD16 were unaffected by weight reduction. CONCLUSIONS: The results suggest that with respect to the management of health conditions, weight reduction for judoists should be composed of exercise training and energy restriction should be moderate.

Adult↗
PubMed2001

Recombination hot spot of hepatitis B virus genome binds to members of the HMG domain protein family and the Y box binding protein family; implication of these proteins in genomic instability.

OBJECTIVE: Previously we hypothesized that the occurrence of hepatocellular carcinoma (HCC) is enhanced by genomic instability induced by the integrated hepatitis B virus (HBV) DNA. Using an in vitro recombination assay, we showed that a subgenomic fragment of HBV DNA designated 15AB (nt1855-1914) is indispensable for in vitro recombination, and also showed the existence of 15AB binding protein. On the assumption that the 15AB binding protein may be a candidate cellular recombinogenic protein which accelerates genomic instability and hepatocarcinogenesis, we tried to isolate it by southwestern screening. RESULTS AND CONCLUSION: We obtained several positive clones including mouse upstream binding factor (UBF) and DNA binding protein A (dbpA). UBF belongs to an HMG domain protein family and dbpA belongs to a Y box binding protein family. 15AB binding seemed to be mediated by the conserved DNA binding domains in these families, because other members in the families such as HMG1 and YB-1 also bound to 15AB. We report them here because several documents have already suggested the possible association of these families and DNA recombination.

Animals↗
PubMed2001

Relationship between mineral and trace element concentrations in drinking water and gastric cancer mortality in Japan.

It is well known that the incidence and mortality from gastric cancer in Japan are the highest in the world. This is thought to be due, in part, to dietary habit, including a high salt intake. There are, however, no epidemiological reports to describe the relationship between ingestion of mineral and trace elements and gastric carcinogenesis. In this study, we determined the concentrations of 14 elements in drinking water from 34 water treatment plants in Aomori Prefecture, Japan, and studied how element concentrations were geographically associated with gastric cancer mortality rate. Gastric cancer mortality was calculated from the data of the Annual Aomori Health Report. Multiple regression analysis (stepwise method of decreasing the number of variables) was performed by using age-adjusted mortality of gastric cancer by gender as objective variables and each element concentration as an explanatory variable. The standardized partial regression coefficient was significant in men for zinc (-0.59, P = 0.004), lead (1.01, P = 0.013), strontium (1.23, P = 0.007), and selenium (-1.62, P = 0.004), whereas it was significant in women for lead (-0.65, P = 0.022), strontium (0.51, P = 0.035), and gold (0.70, P = 0.019). It is suggested that selenium and zinc may aid in the prevention of gastric carcinogenesis. However, the significant relationship of sodium (a component of salt) to gastric carcinogenesis was not observed, although many previous epidemiological studies in Japan have shown this relationship.

Adult↗
PubMed2001

[Complement activity among individuals at a ground self-defense force base].

OBJECTIVE: This study aims to examine the distribution of hemolytic complement activity, the prevalence of hypocomplementemia and the disorders causing hypocomplementemia among individuals taking part in a mass screening program. METHODS: The subjects consisted of 1340 male Japanese participating in a mass screening program at a Ground Self-Defense Force base in Asaka. We measured the hemolytic complement activity (CH50) after overnight fasting. The CH50 levels for hypercomplementemia and hypocomplementemia were defined as those outside the range of mean +/- 2 SD, respectively. We next measured the concentration of complement components: CIq, C4, B, C3, C5, C9, and C1-inhibitor for men with hypocomplementemia. Rheumatoid factor, ANA, HBsAg, HbsAb, and HCVAb were also measured. RESULTS: The mean +/- SD of age was 43.7 +/- 5.7. The CH50 levels ranged from 7.2 to 66.4 U/ml (mean +/- SD = 37.1 +/- 4.0 U/ml). Twenty-one and 37 men were classified as having hypocomplementemia (CH50 < 29.1 U/ml) and hypercomplementemia (CH50 > 45.1 U/ml), respectively. The age of the individuals with hypocomplementemia was 43.9 +/- 5.6 (Mean +/- SD) years. Three men with C9 deficiencies, 2 men with C5 deficiencies and 7 men with cold activation were identified among the 21 hypocomplementemic men. Three hepatitis C and 2 hepatitis B patients were also found among the 21 hypocomplementemic men. Other disorders found among the hypocomplementemic men were 3 glomerulonephritides and 1 possible SLE. CONCLUSION: We examined the distribution of CH50 levels in 1340 adult male Japanese. We identified 21 men with hypocomplementemia, and also found 5 cases of complement component deficiencies among 21 hypocomplementemic men. In addition the measurement of the complement activity may have also helped detect the presence of hepatitis, hypocomplementemic glomerulonephritis and collagen disease at an early stage.

Adult↗
PubMed2001

[Characteristics of heterosexually acquired AIDS in Japan. An inter-country comparison using AIDS Surveillance data].

OBJECTIVES: To identify epidemiological characteristics of heterosexually acquired AIDS in Japan, with emphasis on potential influence on future trends. METHODS: National AIDS Surveillance data in Japan were compared with those in the UK and US, where detailed information is available from well-established surveillance procedures. Data on AIDS cases diagnosed until the end of 1996, particularly those acquired heterosexually, were analyzed by year of diagnosis, gender and age group. RESULTS: The number of heterosexually acquired AIDS cases in Japan has continued to increase, while those in the UK and US leveled out or decreased recently. The increase during a two-year period after reaching a certain number of cases per year was found to be 2.3-fold in Japanese, 2.4-fold in UK whites and 5-fold in US whites. The male to female ratio (M/F) for heterosexually acquired AIDS was 6.3 among Japanese, while the ratio was 1.1 and 0.5 in the UK and US, respectively. The age distribution at AIDS diagnosis demonstrated a peak from 35 to 54 years of age among Japanese males, as compared to 30 to 34 among males in the UK and the US. No significant difference was apparent in the age distribution among females in the three countries. CONCLUSIONS: The relatively small number of AIDS cases in Japan is attributable to the late introduction of HIV and the limited chance of heterosexual transmission from homosexual/bisexual men and injecting drug users. In addition, transmission has probably most often occurred between middle-aged Japanese males and non-Japanese females. As there is a growing risk of HIV infection among Japanese females and young Japanese males, new prevention strategies targeting these groups are urgently required.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Clinical study of testicular germ cell tumors.

A clinical statistical analysis on 65 patients with 68 testicular germ cell tumors was performed. Thirty-six testes (53.7%) had seminomas and the remainder non-seminomatous germ cell testicular tumors (NSGCTTs). Of the seminomas, 31 (88.6%) were in stage I and the others showed distant metastases at presentation. Of the 32 NSGCTTs, 22 (68.8%) were in stage I. The average ages of the patients with seminomas and NSGCTTs were 40.4 and 29.9 years, respectively. Thirty-nine patients (60.0%) had tumors on the right side, 23 (35.4%) on the left and 3 (4.6%) in both testes. Five patients had a past history of cryptorchidism. Chief complaints in 49 patients (73.1%) were a painless scrotal mass. The interval from clinical onset to presentation was longer in seminoma patients than in NSGCTT patients (10.9 months on average versus 3.4 months). Immunosuppressive acidic protein (IAP) was a useful diagnostic tumor marker as well as alpha-feto protein (AFP), beta-human chorionic gonadotropin (beta-hCG) and lactic dehydrogenase (LDH). We adopted a surveillance policy in more than half of the stage I patients and obtained acceptable results. In the remaining cases, therapies including combination chemotherapy, radiation and salvage operation were performed after orchiectomy. The three-year survival rate was 98.0, 100.0 and 26.7%, for stage I, II and III patients respectively.

Adult↗
PubMed2000

Determination of a new oral cephalosporin, cefmatilen hydrochloride hydrate, and its seven metabolites in human and animal plasma and urine by coupled systems of ion-exchange and reversed-phase high-performance liquid chromatography.

Multidimensional HPLC systems with coupled anion-exchange, cation-exchange, and reversed-phase columns, and ultraviolet and electrochemical detectors were developed for the determination of cefmatilen and its seven metabolites in the plasma and urine of humans and animals. These target compounds with a wide range of polarities were efficiently separated and determined by HPLC assay methods with simple pretreatments, deproteinization of plasma and dilution of urine. The assay methods showed good linearity, precision and accuracy. The methods were successfully applied to pharmacokinetic and metabolic studies of cefmatilen hydrochloride hydrate administered orally to humans and animals.

Animals↗
PubMed2000

Determination of a sulfur-containing drug in human plasma by an improved method for sulfur chemiluminescence detection in combination with capillary gas chromatography.

An improved method for sulfur chemiluminescence detection in combination with capillary gas chromatography was established. The method was applied to the analysis of a sulfur-containing antiasthma drug, S-1452, and its nine metabolities in human plasma. The high selectivity and sensitivity of the method allowed accurate quantitation of trace levels of these compounds in human plasma with no interferences from the biological components present. To enable stable measurements and maintain reproducibility over a long period, the performance characteristics of a commercially available instrument were investigated. The gas seal in the injection port was found to easily corrode through interaction of the sulfur analyte with the metal gas seal. To prevent this, a disk made from an alloy of platinum and gold (60:40) was mounted on the gas seal. The reproducibility of the measurement was improved remarkably by using the disk. The use of compressed air of high purity significantly lowered the signal-to-noise ratio. The optical filter was kept clean by using a nickel catalyst to trap ozone in place of copper manganese oxide (CuMn2O4). These improvements raised the sensitivity and selectivity with the lower quantitation limits of 0.5-1.0 ng/mL in human plasma.

Air↗
PubMed2000

The management of pelvic chondrosarcoma in Japan. Japanese Musculo-Skeletal Oncology Group.

A review of 135 patients with pelvic chondrosarcoma who had been treated at 58 institutions in Japan between 1989 and 1998. In this series ablative surgery was necessary in 14 patients, and a limb salvage procedure performed in 121 patients. The surgical margins were "intra-lesional" in 27 patients, "marginal" in 30, "wide" in 77 and "unspecified" in 1. Local recurrence occurred in 33 patients and distant metastases in 25. Post-operative infection occurred in 25 patients. Revision was performed in 10 patients. The oncological outcome was "disease free" in 92 patients, "alive with disease" in 17 and "dead because of the disease" in 26. The cumulative prospective 10-year survival rate for all patients was 65%. The 6 statistically significant prognostic factors that determined the outcome were: - surgical stage, site of tumour, size of tumour, surgical margin, functional mobility and activity level after surgery. Excision of the tumour with a wide margin, or with a wide margin with partly marginal areas, and subsequent stable reconstruction are essential for improving the results of pelvic chondrosarcoma treatment.

Acetabulum↗
PubMed2000

A multidisciplinary approach to the treatment of malignant pelvic bone tumors: results with eight consecutive patients.

The prognosis for malignant pelvic bone tumors is worse than that for malignant bone tumors of the extremities because definitive surgery in the pelvis is often difficult to accomplish. The results for eight patients who were treated consecutively with a multidisciplinary approach, from 1990, were analyzed. The histologic diagnosis was osteosarcoma in five patients, chondrosarcoma in two, and Ewing's sarcoma in one. Five lesions arose in the ilium and three in the pubis. The extraosseous tumors decreased in size and/or were encapsulated as a result of preoperative chemotherapy in six patients, four of these achieving a wide surgical margin. With respect to tumor location and surgical margin, all five lesions in the ilium involved the sacrum, four of these being resected with an inadequate margin. The three lesions in the pubis were resected with an adequate margin. Local recurrence was observed in two patients who had been treated with an inappropriate margin. During the period between 18 and 57 months after the first operation, five patients were continuously free of disease and one was still alive but had lung metastases. Our results indicate that a patient's chances of definitive surgery may be enhanced by a multidisciplinary approach, although the management of sacroiliac involvement remains challenging.

Adult↗