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Biomedical subjects

S Tanaka

Publications and source records attributed to S Tanaka.

At least 37 records · Page 2Linked to original sources
PubMed2006

Nuclear and mitochondrial DNA microsatellite instability in gastrointestinal stromal tumors.

OBJECTIVE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. Nuclear (nMSI) and mitochondrial microsatellite instability (mtMSI) play important roles in tumorigenesis in various organs. The aim of this study was to evaluate the role of nMSI and mtMSI in GISTs. METHODS: Samples from 74 mesenchymal tumors were collected. nMSI and mtMSI were examined by microsatellite assay at BAT26 and D310 mononucleotide repeats in mtDNA, respectively. We compared nMSI, mtMSI and clinicopathologic features, including patient age and sex, tumor location, tumor size, presence of tumor ulceration and presence of distant metastasis, for 51 GISTs for which these data were available. RESULTS: nMSI and mtMSI were detected in 3 (5%) and 10 (16%) of the 62 GISTs, respectively. There was no significant relationship between nMSI, mtMSI and clinicopathologic features. CONCLUSION: These results suggest that mtMSI may play a role, but that nMSI may play little role in the development of GISTs.

Adult↗
PubMed2006

Analysis of parameter variations in L-Q equations for river runoff processes from the viewpoint of spatial and temporal conditions.

This study aims to find out variation characteristics of the parameters of 'a' and 'b' in L = a x Q(b), an empirical equation for run-off loading (L) and flow rate (Q), by evaluating the effects of flow conditions and regional properties of the watersheds on the values. We selected the Kamo River basin (155 km2) as a study field, and conducted various kinds of investigations, such as 80 day high frequency observations, continuous monitoring for more than 2 years, storm event surveys, and simultaneous surveys of 39 stations. Then, we obtained 7-170 data in each of 39 sampling stations. The main results obtained are as follows: (1) L-Q equation with a range of 'a' can express L-Q relation in most of the WQIs (water quality indices); (2) 'a' receives temporal (flow condition) effects more in SS, VSS and Al, while it receives regional effect more in inorganic carbon, TN, Ca and Fe; (3) both of flow change in storm events, and base flow levels affect the L-Q relation, and their effects can classify the WQIs into several groups; (4) the effects of regional properties were obviously observed in 'a', and quantitatively evaluated, especially for density of population.

Algorithms↗
PubMed2006

Differential effects of heterocyclic amines on poly(ADP-ribose) polymerase-1 and mono-ADP-ribosyltransferase A.

Heterocyclic amines (HCAs) have been shown to be carcinogenic in a variety of experimental systems. The purpose of the present study was to determine the in vitro effect of HCAs on the activity of the DNA repair enzyme poly(ADP-ribose) polymerase-1 (PARP-1). HCAs were also tested on the arginine-specific mono-ADP-ribosyltransferase A (MART-A), an enzyme involved in signal transduction and cytoskeletal realignment. 3-Amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) at 1 mM caused a 134% increase in PARP-1 activity and a 93% decrease in activity at 5 mM (IC(50) = 2.2 mM). This dual effect is unique among inhibitors of this enzyme. On the other hand, Trp-P-2 activated MART-A at all concentrations tested, the peak being at 3 mM (>171% increase). In contrast, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) inhibited concentration-dependently both enzymes, PARP-1 (IC(50) = 0.22 mM) and MART-A (IC(50) = 2.8 mM). With nine other HCAs tested, predominantly inhibitory effects were observed. These results may assist our understanding of the carcinogenic mechanism of action and the dose-dependency of HCAs in animal bioassays.

ADP Ribose Transferases↗
PubMed2005

Dopaminergic control of working memory and its relevance to schizophrenia: a circuit dynamics perspective.

This article argues how dopamine controls working memory and how the dysregulation of the dopaminergic system is related to schizophrenia. In the dorsolateral prefrontal cortex, which is the principal part of the working memory system, recurrent excitation is subtly balanced with intracortical inhibition. A potent controller of the dorsolateral prefrontal cortical circuit is the mesocortical dopaminergic system. To understand the characteristics of the dopaminergic control of working memory, the stability of the circuit dynamics under the influence of dopamine has been studied. Recent computational studies suggest that the hyperdopaminergic state is usually stable but the hypodopaminergic state tends to be unstable. The stability also depends on the efficacy of the glutamatergic transmission in the corticomesencephalic projections to dopamine neurons. When this cortical feedback is hypoglutamatergic, the circuit of the dorsolateral prefrontal cortex tends to be unstable, such that a slight increase in dopamine releasability causes a catastrophic jump of the dorsolateral prefrontal cortex activity from a low to a high level. This may account for the seemingly paradoxical overactivation of the dorsolateral prefrontal cortex observed in schizophrenic patients. Given that dopamine transmission is abnormal in the brains of patients with schizophrenia and working memory deficit is a core dysfunction in schizophrenia, the concept of circuit stability would be useful not only for understanding the mechanisms of working memory processing but for developing therapeutic strategies to enhance cognitive functions in schizophrenia.

Dopamine↗
PubMed2005

Investigation of a Kubo-formula-based approach to estimate DNA conductance in an atomistic model.

A novel approach to estimate DNA conductance based upon Kubo formula is presented and discussed. Using this approach, the effects of base pair mismatches, different conformational changes and base pair sequence on DNA electrical properties were investigated. The results were compared with the data from other methods. The new approach makes possible very fast estimation of conductance spectra for oligonucleotides with hundreds of base pairs and can easily be extended to treat arbitrary chemical modifications of DNA.

Base Pair Mismatch↗
PubMed2005

Analysis of feeding behavior with direct linear transformation.

AIM: The sucking pattern of term infants is composed of a rhythmic alteration of expression and suction movements. The aim is to evaluate if direct linear transformation (DLT) method could be used for the assessment of infant feeding. SUBJECT AND METHODS: A total of 10 gnormalh infants and two infants with neurological disorders were studied using DLT procedures and expression/suction pressure recordings. Feeding pattern of seven gnormalh infants were evaluated simultaneously recording DLT and pressures. The other infants were tested non-simultaneously. We placed markers on the lateral angle of the eye, tip of the jaw, and throat. The faces of infants while sucking were recorded in profile. The jaw and throat movements were calculated using the DLT procedure. Regression analysis was implemented to investigate the relationship between suction and expression pressures and eye-jaw and eye-throat movement. All regression analyses investigated univariate relationships and adjusted for other covariates. RESULTS: Ten gnormalh infants demonstrated higher suction pressure than expression pressure, and their throat movements were larger than jaw movements. Two infants with neurological problems did not generate suction pressure and demonstrated larger movements in their jaw than throat. The simultaneous measurement (n=7) showed a significant correlation, not only between eye-jaw distance and the expression pressure, but also between eye-throat distance and suction pressure. The change in the eye-jaw distance was smaller than the changes in the eye-throat distance in gnormalh infants (p<0.001). CONCLUSIONS: The DLT method can be used to evaluate feeding performance without any special device.

Humans↗
PubMed2005

Monocyte chemoattractant protein 1 and macrophage cyclooxygenase 2 expression in colonic adenoma.

BACKGROUND AND AIMS: Cyclooxygenase 2 (COX-2) expression in subepithelial macrophages of colorectal adenoma has been suggested as the first in a series of steps leading to colorectal tumorigenesis. We tested the hypothesis that chemokines released from human colorectal adenoma epithelium might be involved in COX-2 expression in macrophages of the lamina propria. METHODS: Endoscopic samples of sporadic colorectal adenomas were tested by enzyme linked immunosorbent assay for chemokines involved in macrophage chemotaxis. Localisation of adenoma macrophage chemoattractant protein 1 (MCP-1) and COX-2 were determined by immunohistochemistry. The effects of MCP-1, in the presence or absence of celecoxib, on COX-2 expression, and prostaglandin (PG) E(2) and vascular endothelial growth factor (VEGF) release, were examined in human macrophages isolated from peripheral blood. RESULTS: MCP-1 levels were markedly higher in adenoma with mild-moderate dysplasia (129.7 (19.9) pg/mg protein) and severe dysplasia (227.9 (35.4) pg/mg protein) than in normal colonic mucosa (55.8 (4.2) pg/mg protein). Other chemokine levels, macrophage inflammatory proteins (MIP)-1alpha and MIP-1beta, and the chemokine regulated on activation of normal T cell expressed and secreted (RANTES) did not vary significantly between adenoma and normal mucosa. MCP-1 levels in both adenoma and normal colonic mucosa increased significantly three hours after tissue cultivation in vitro. MCP-1 immunoreactivity was restricted to the adenoma epithelium, with no reactivity seen in adjacent normal epithelial cells. MCP-1 stimulated COX-2 expression and PGE(2) and VEGF release in human macrophages. Celecoxib, a selective COX-2 inhibitor, inhibited MCP-1-induced PGE(2) and VEGF release in macrophages. Addition of exogenous PGE(2) reversed this inhibitory effect on VEGF release, suggesting that MCP-1 in adenoma epithelial cells might be involved in COX-2 expression and subsequent macrophage activation. CONCLUSIONS: MCP-1 in colorectal adenoma epithelial cells might be involved in macrophage migration and COX-2 expression, leading to the subsequent development of colonic adenoma.

Adenoma↗
PubMed2005

Clinical features of gastric cancer discovered after successful eradication of Helicobacter pylori: results from a 9-year prospective follow-up study in Japan.

BACKGROUND: Eradication of Helicobacter pylori is expected to prevent the development of gastric cancer. However, gastric cancer is sometimes discovered after successful eradication of H. pylori. AIM: To conduct a prospective study to determine the clinical features of patients who underwent successful eradication and were later diagnosed with gastric cancer. METHODS: A total of 1787 patients (1299 males and 488 females; mean age, 58.2 years; range: 15-84) who underwent successful eradication therapy between April 1994 and March 2001 were our study subjects. RESULTS: Gastric cancer occurred at a rate of 1.1% (20 of 1787) during the follow-up period. Gastric cancer comprises six of 105 (5.7%) with early gastric cancer after endoscopic resection, 12 of 575 (2.1%) with gastric ulcer and two of 453 (0.4%) with atrophic gastritis. Gastric cancer did not develop in any patient with duodenal ulcer. All patients with gastric cancer had baseline severe atrophic gastritis in the corpus. CONCLUSION: Careful endoscopic examination is necessary even after successful eradication of H. pylori in patients with early gastric cancer or gastric ulcer with severe mucosal atrophy in the corpus.

Adolescent↗
PubMed2005

Morphological changes in human gastric tumours after eradication therapy of Helicobacter pylori in a short-term follow-up.

BACKGROUND: It is controversial as to whether the development of gastric cancer is influenced by Helicobacter pylori eradication. If eradication itself influences the tumour morphology, this may affect the tumour discovery rate. AIM: To investigate the morphological changes in the gastric neoplasm after H. pylori eradication. METHODS: We studied 37 patients with eradication therapy. After a 1-month follow-up, endoscopic re-evaluation was performed and the appearance was compared with first image. All lesions were resected endoscopically, and were subjected to histological assessment and to immunohistochemistry. Serum gastrin levels were determined before and after eradication. RESULTS: Twenty-nine of 37 patients underwent successful eradication. The appearance of 11 lesions (33% of 33 lesions) became indistinct after successful eradication. All lesions were of the superficial-elevated type and the height of the lesions decreased. We detected normal columnar epithelium over the neoplasm in eight of the lesions. Higher expression of single-stranded deoxyribonucleic acid in the deep area was characteristic in tumours with an indistinct appearance. These changes did not correlate with the serum gastrin levels. CONCLUSIONS: The morphology of the gastric neoplasm change after eradication in the short-term. This may contribute to the decreased tumour discovery rate.

Adenocarcinoma↗
PubMed2005

Characteristics of carbonaceous aerosols in Beijing, China.

Carbonaceous aerosols and PM10 were monitored from September 8 to November 30, 2002, in a semi-urban site (Tsinghua University) in Beijing. Daily concentrations of OC and EC ranged from 7.1 to 65.9 microgCm(-3) and from 1.3 to 26.1 microgCm(-3), with the overall average concentrations of 21.2 microgCm(-3) and 7.3 microgCm(-3), respectively. The diurnal variation of carbonaceous concentrations on 2 h basis presented two-peak trend, which was attributed to the cooperative effect of local meteorological conditions and anthropogenic sources such as traffic exhaust and human outdoor activities. Daily average OC/EC ratio varied between 1.5 and 5.3 with an average of 3.0. Strong correlation between OC and EC (R2=0.8) indicated that their main sources were common. The frequency of OC/EC ratio presented Gaussian normal distribution trend in fall, of which the peak value appeared in the range of 2.8-5. In winter, it presented bi-peak mode, with the first peak near 1.4-1.6, and the second between 2.8 and 5. The high value (2.8-5) implied the SOC formation in both seasons, and the low one probably suggested the primary OC/EC ratio from coal burning in winter. Averagely, PM10 and carbonaceous species exhibited higher concentrations in Wednesday than in other weekdays, which could be ascribed to the low wind speed (1.6 ms(-1)) and high humidity (62.9%). OC was the abundant component accounting for 76% of TC. OC and EC contributed 15% and 5% to PM10, respectively. The estimation on a minimum OC/EC ratio (1.5) basis showed that SOC accounted more than 50% for the total organic carbon. Even in winter, the SOC contribution to OC was also significant, as high as 40%.

Aerosols↗
PubMed2005

Eradication of Helicobacter pylori increases the incidence of hyperlipidaemia and obesity in peptic ulcer patients.

BACKGROUND: Eradication of Helicobacter pylori improves clinical symptoms and quality of life in patients with peptic ulcer. AIM: To investigate the effect of eradication of H. pylori on body mass index and incidence of hyperlipidaemia in patients with peptic ulcer. PATIENTS AND METHODS: The study population comprised 50 patients (42 men, 8 women; mean age, 51 years; 28 gastric ulcer, 22 duodenal ulcer) who underwent physical and blood examination before and 1 year after undergoing eradication therapy and 100 sex- and age-matched control subjects. Body mass index, total cholesterol and triglyceride were measured before and 1 year after therapy. RESULTS: The eradication therapy group showed a significant increase in body mass index (22.7+/-2.5 kg/m2 before eradication versus 23.6+/-2.6 kg/m2 after eradication, p < 0.01), serum total cholesterol (204.1+/-33.2 mg/dL versus 221.2+/-38.8 mg/dL, p < 0.01), and triglyceride. Additionally, the eradication therapy group showed a significant increase in the incidence of hypercholesterolemia (30% versus 58%, p<0.01), hypertriglyceridaemia (28% versus 44%, p < 0.01) and obesity (12% versus 22%, p <0.05) 12 months after therapy. CONCLUSION: Our findings show that eradication of H. pylori significantly increases the incidence of hyperlipidaemia and obesity in patients with peptic ulcer.

Adult↗
PubMed2005

A prospective randomized comparative study on the safety and tolerability of transnasal esophagogastroduodenoscopy.

BACKGROUND AND STUDY AIM: Transnasal esophagogastroduodenoscopy (EGD) with a small-caliber endoscope is well tolerated by patients. However, the effect of this procedure on cardiopulmonary function has not been fully investigated. The aim of this prospective, randomized study was to investigate the effect of transnasal EGD in comparison with transoral EGD on cardiopulmonary function. PATIENTS AND METHODS: The study involved 450 patients referred for diagnostic EGD. Patients were randomly assigned to one of three types of unsedated EGD (150 patients per group): transnasal EGD using a small-caliber endoscope (the "XP-N" group), transoral EGD using the same small-caliber endoscope ("XP-O" group), and transoral EGD using a conventional endoscope ("XQ" group). Systolic and diastolic blood pressure, pulse rate, and arterial oxygen saturation were monitored before, and 2, 4 and 6 minutes after intubation, and just after endoscope extubation. Gagging episodes were also counted, to determine tolerance. RESULTS: It was not possible to perform transnasal EGD in 12 patients (8.0%). A small amount of epistaxis was observed in eight (5.8%) of 138 patients who were examined successfully by transnasal EGD. Systolic and diastolic blood pressure, pulse rate, rate-pressure product (pulse rate x systolic blood pressure/100), and the drop in arterial oxygen saturation in the XQ group were significantly greater than in the XP-N and XP-O groups at each time point. In the XP-N group, these parameters were significantly lower than those in the XP-O group at 2 minutes after intubation. Of the tree groups the number of gagging episodes was significantly lower in the XP-N group. CONCLUSION: Transnasal EGD is safer than transoral EGD as it is associated with fewer adverse effects on cardiopulmonary function and is better tolerated by patients.

Adult↗
PubMed2005

Effect of long-term half-dose famotidine therapy on corpus gastritis in peptic ulcer disease.

BACKGROUND: Recent studies showed that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection. AIM: The aim of this study was to evaluate the effect of famotidine, a histamine receptor antagonist on corpus gastritis in patients with peptic ulcer disease. METHODS: We enrolled 287 patients, 173 with duodenal ulcer and 114 with gastric ulcer and 100 patients with H. pylori-positive gastritis as control subjects. Patients with peptic ulcer were classified according to whether or not they received famotidine-maintenance therapy (20 mg/day) after primary treatment. At the time of endoscopy, biopsy specimens were obtained from the antrum and the corpus. The degrees of neutrophil and lymphocyte infiltration, atrophy and intestinal metaplasia were scored according to the updated Sydney System. RESULTS: The degrees of neutrophil infiltration and atrophy in the corpus were significantly less in patients with gastric ulcer or duodenal ulcer than in patients with H. pylori-positive gastritis (P < 0.01). Differences in the degrees of neutrophil infiltration and atrophy in the corpus between the non-maintenance group and the maintenance group were not significant. CONCLUSION: Long-term therapy with famotidine does not appear to lead to an increase in the incidence of corpus gastritis or corpus atrophy in patients with peptic ulcer disease.

Adolescent↗
PubMed2005

Actinobacillus actinomycetemcomitans Y4 capsular polysaccharide induces IL-1beta mRNA expression through the JNK pathway in differentiated THP-1 cells.

Capsular polysaccharide from Actinobacillus actinomycetemcomitans Y4 (Y4 CP) induces bone resorption in a mouse organ culture system and osteoclast formation in mouse bone marrow cultures, as reported in previous studies. We also found that Y4 CP inhibits the release of interleukin (IL)-6 and IL-8 from human gingival fibroblast (HGF). Thus Y4 CP induces various responses in localized tissue and leads to the secretion of several cytokines. However, the effects of Y4 CP on human monocytes/macrophages are still unclear. In this study, THP-1 cells, which are a human monocytic cell line, were stimulated with Y4 CP, and we measured gene expression in inflammatory cytokine and signal transduction pathways. IL-1beta and tumour necrosis factor (TNF)-alpha mRNA were induced from Y4 CP-treated THP-1 cells. IL-1beta mRNA expression was increased according to the dose of Y4 CP, and in a time-dependent manner. IL-1beta mRNA expression induced by Y4 CP (100 microg/ml) was approximately 7- to 10-fold greater than that in the control by real-time PCR analysis. Furthermore, neither PD98059, a specific inhibitor of extracellular signal-regulated kinase nor SB203580, a specific inhibitor of p38 kinase prevented the IL-1beta expression induced by Y4 CP. However, JNK Inhibitor II, a specific inhibitor of c-Jun N-terminal kinase (JNK) prevented the IL-1beta mRNA expression induced by Y4 CP in a concentration-dependent manner. These results indicate that Y4 CP-mediated JNK pathways play an important role in the regulation of IL-1beta mRNA. Therefore, Y4 CP-transduced signals for IL-1beta induction in the antibacterial action of macrophages may provide a therapeutic strategy for periodontitis.

Aggregatibacter actinomycetemcomitans↗
PubMed2005

Henneguya pagri n. sp. (Myxozoa: Myxosporea) causing cardiac henneguyosis in red sea bream, Pagrus major (Temminck & Schlegel).

Henneguya pagri n. sp. (Myxozoa: Myxosporea) is described from netpen-cultured red sea bream, Pagrus major, in Japan. Affected fish displayed anaemic gills, an enlarged bulbus arteriosus and internal haemorrhaging in the pericardial cavity. Disease outbreaks occurred during the summer and the prevalence of infection reached 75% in August. Plasmodia of H. pagri developed in the bulbus arteriosus of red sea bream, in which degenerative cardiomyopathy was observed. Following maturation of the parasite, the influx of spores into the gills caused congestion of the gill capillaries, resulting in proliferative branchitis. Spores (10.5 x 7.5 microm) were ovoid with two caudal appendages (29.6 microm in average length), with a whip-like extension from the end. Partial small subunit ribosomal RNA gene sequences of H. pagri are closely related to those of H. lateolabracis infecting the bulbus arteriosus of Chinese sea bass, Lateolabrax sp.

Animals↗