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Biomedical subjects

Takeshi Tsuji

Publications and source records attributed to Takeshi Tsuji.

18 recordsLinked to original sources
PubMed2007

Fast preparation of PtRu catalysts supported on carbon nanofibers by the microwave-polyol method and their application to fuel cells.

PtRu alloy nanoparticles (24 +/- 1 wt %, Ru/Pt atomic ratios = 0.91-0.97) supported on carbon nanofibers (CNFs) were prepared within a few minutes by using a microwave-polyol method. Three types of CNFs with very different surface structures, such as platelet, herringbone, and tubular ones, were used as new carbon supports. The dependence of particles sizes and electrochemical properties on the structures of CNFs was examined. It was found that the methanol fuel cell activities of PtRu/CNF catalysts were in the order of platelet > tubular > herringbone. The methanol fuel cell activities of PtRu/CNFs measured at 60 degrees C were 1.7-3.0 times higher than that of a standard PtRu (29 wt %, Ru/Pt atomic ratio = 0.92) catalyst loaded on carbon black (Vulcan XC72R) support. The best electrocatalytic activity was obtained for the platelet CNF, which is characterized by its edge surface and high graphitization degree.

Journal Article↗
PubMed2006

Micturition induced seizures: ictal EEG and subtraction ictal SPECT findings.

We report an 8-year-old girl with seizures induced by micturition. Her seizures were characterized by extension of upper extremities with preserved consciousness. Magnetic resonance imaging and interictal electroencephalograms were normal. Ictal electroencephalogram showed low voltage fast waves without clear focal features followed by frontal dominant rhythmic multiple spikes. Subtraction ictal single photon emission computed tomography revealed a significant increase in blood flow in the mesial frontal area.

Child↗
PubMed2006

ACTH therapy for generalized seizures other than spasms.

PURPOSE: We reviewed our experience with ACTH for the treatment of intractable generalized seizures other than spasms. METHODS: Efficacy and adverse effects of ACTH against intractable generalized seizures other than spasms were retrospectively investigated in 15 patients treated between 1991 and 2003. The median age of the patients at ACTH therapy was 42 months. The targeted type of seizure was brief tonic in 6, atypical absence in 6, atonic in 2, and myoclonic in 1. The dose of ACTH was 0.01-0.015 mg/kg in most patients. The effect of ACTH was determined at the end of ACTH therapy, and 3 months and 1 year after ACTH therapy. RESULTS: Seizure freedom was obtained in 13 of 15 patients. However, 6 of them had a recurrence of seizures within 3 months after ACTH therapy. ACTH was the most effective in patients with atypical absence seizures. Statistical analysis showed that the number of injection and total dose of ACTH were smaller in patients with atypical absence seizures than in those with brief tonic seizures. Adverse effects were frequent but serious one was not observed. CONCLUSION: ACTH therapy was effective in patients with intractable generalized seizures other than spasms. However, its efficacy was often transient. ACTH can be useful for generalized seizures other than spasms but its limitation should be considered.

Adrenocorticotropic Hormone↗
PubMed2006

Multiple pathways for noxious information in the human spinal cord.

To investigate the pathways of noxious information in the spinal cord in humans, we recorded cortical potentials following the stimulation of A-delta fibers using a YAG laser applied to two cutaneous points on the back at the C7 and Th10 level, 4cm to the right of the vertebral spinous process. A multiple source analysis showed that four sources were activated; the primary somatosensory cortex (SI), bilateral parasylvian region (Parasylvian), and cingulate cortex. The activity of the cingulate cortex had two components (N2/P2). The mean peak latencies of the activities obtained by C7 and Th10 stimulation were 166.9 and 186.0 ms (SI), 144.3 and 176.8 ms (contralateral Parasylvian), 152.7 and 185.5 ms (ipsilateral Parasylvian), 186.2 and 215.8 ms (N2), and 303.0 and 332.3 ms (P2). Estimated spinal conduction velocities (CVs) of the respective activities were 16.8, 9.3, 8.7, 10.1 and 10.7 m/s. CV of SI was significantly faster than the others (P<0.05). Therefore, our results suggested that noxious signals were conveyed through at least two distinct pathways of the spinal cord probably reaching distinct groups of thalamic nuclei. Further studies are required to clarify the functional significance of these two pathways.

Adult↗
PubMed2006

Impact of lymph node metastasis on survival in patients with pathological T1 carcinoma of the ampulla of Vater.

To determine the prognostic factors for patients with pathological T1 (pT1) carcinoma of the ampulla of Vater, 36 consecutive patients with carcinoma of the ampulla of Vater who underwent surgery were retrospectively analyzed in terms of clinicopathological features. The overall 5-year Kaplan-Meier survival in all patients was 50.2%, and the median survival of all patients was 64.0 months. Factors favorably influencing a long-term outcome were the absence of lymph node metastasis (P < 0.0001), the absence of ulcer formation of the tumor (P = 0.0062), and the absence of tumor invasion into the duodenum (P = 0.0025) and the pancreas (P = 0.0098). In a multivariate analysis, lymph node metastasis was the only predictor of survival (P = 0.0023). In the pT1 stage patients, 20% of the patients had lymph node metastasis, and their survival was statistically poor compared to the pT1 patients without lymph node metastasis (P = 0.017). As for survival after the operation, there was no significant difference between pancreatoduodenectomy and pylorus-preserving pancreatoduodenectomy.

Aged↗
PubMed2006

Amplitude spectral analysis of theta/alpha/beta waves in preterm infants.

The aim of this study is to clarify the usefulness of amplitude spectral analysis for the evaluation of maturational changes of theta, alpha, and beta activities in preterm infants. We chose 10 healthy infants, who were born without complications other than prematurity, who were 29-30 weeks, 31-32 weeks, and 33-34 weeks of postconceptional age, respectively, at time of electroencephalogram recordings. Fast Fourier transform algorithm was applied for amplitude spectral analysis. The analyzed data were divided into five frequency bands: theta 1 4-6 Hz, theta 2 6-8 Hz, alpha 8-13 Hz, beta 1 13-20 Hz, and beta 2 20-30 Hz. The average amplitude of six segments with continuous patterns with high-voltage slow waves of preterm infants was calculated in each frequency band. A significant reduction of the amplitude along with postconceptional age was present in all leads in theta 1 and theta 2 bands. On the other hand, a significant correlation with postconceptional age was not observed in alpha, beta 1, or beta 2 bands. In conclusion, maturational electroencephalographic changes assessed by amplitude spectral analysis were prominent in theta activities and were not remarkable in alpha or beta activities.

Brain↗
PubMed2005

Temporal analysis of cortical mechanisms for pain relief by tactile stimuli in humans.

The mechanisms by which vibrotactile stimuli relieve pain are not well understood, especially in humans. We recorded cortical magnetic responses to paired noxious (intra-epidermal electrical stimulation, IES) and innocuous (transcutaneous electrical stimulation, TS) stimuli applied to the back at a conditioning-test interval (CTI) of -500 to 500 ms. Results showed that IES-induced responses were remarkably attenuated when TS was applied 20-60 ms later and 0-500 ms earlier than IES (CTI = -60 to 500 ms). Since the signals evoked by IES reached the spinal cord (CTI = -60 to -20 ms conditions) and the cortex (-60 and -40 ms condition) earlier than those evoked by TS, the present results indicate that cortical responses to noxious stimuli can be inhibited by innocuous tactile stimuli at the cortical level, with minimal contribution at the spinal level.

Adaptation, Physiological↗
PubMed2005

Microwave-assisted synthesis of metallic nanostructures in solution.

Microwave (MW) rapid heating has received considerable attention as a new promising method for the one-pot synthesis of metallic nanostructures in solutions. In this concept, advantageous application of this method has been demonstrated by using some typical examples for the preparation of Ag, Au, Pt, and AuPd nanostructures. Not only spherical nanoparticles, but also single crystalline polygonal plates, sheets, rods, wires, tubes, and dendrites were prepared within a few minutes under MW heating. Morphologies and sizes of nanostructures could be controlled by changing various experimental parameters, such as the concentration of metallic salt and surfactant polymer, the chain length of the surfactant polymer, the solvent, and the reaction temperature. In general, nanostructures with smaller sizes, narrower size distributions, and a higher degree of crystallization were obtained under MW heating than those in conventional oil-bath heating. The origin of these characteristic features under MW irradiation is discussed in terms of thermal and non-thermal effects under MW irradiation.

Journal Article↗
PubMed2004

N2O removal in N2 or air by ArF excimer laser photolysis at atmospheric pressure.

A photochemical process is proposed as a new efficient N(2)O removal technique in N(2) or air at atmospheric pressure and room temperature without using any catalysts. N(2)O diluted in N(2) or air was decomposed into N(2), O(2), and NO by using a 193 nm ArF excimer laser. The maximum conversion of N(2)O in N(2)O/N(2) or N(2)O/N(2)/O(2) mixtures was 93% at a laser power of 136 mJ, a repetition frequency of 5 Hz, and an irradiation time of 30 min. The formation ratios of N(2):O(2):NO in N(2)O/N(2) and N(2)O/N(2)/O(2) mixtures were 64:31:5.1% and 60:27:13%, respectively. The decomposition mechanism of N(2)O under 193 nm photolysis was discussed by comparing experimental data with calculated model using known photochemical and gas kinetic data.

Air↗
PubMed2004

Specific gene expression and possible involvement of inflammation in methamphetamine-induced neurotoxicity.

To reveal specific gene expression in methamphetamine (METH) -induced dopamine neurotoxicity, temporal characteristics of METH-induced changes in gene expression in dopaminergic neuronal cells were examined using the cDNA array and the differential display method. A number of genes in the class of "trafficking & protein turnover," "metabolic pathways," "transmitters & receptors," and "growth factors, cytokines" were upregulated after the METH treatment in the cDNA array assay. Whereas, some genes related to trafficking & protein turnover and "modulators, effectors & intracellular transducers" were decreased by METH. Some proteins associated with synaptic vesicle transportation indeed up- or downregulated after the METH treatment. These data suggest that the protein trafficking and degradation system is involved in the dopaminergic cell death induced by METH. Furthermore, focusing on inflammatory reactions after METH injection, possible neuroprotective property of nonsteroidal anti-inflammatory drugs were examined against METH-induced neurotoxicity. Coadministration of NSAID with METH significantly attenuated striatal dopamine terminal degeneration and microgliosis induced by METH, suggesting that the protective effects are based on their inhibitory activity on production of cytokines and nitric oxides or their suppressive action against microglia activation.

Animals↗
PubMed2003

Methamphetamine-induced neurotoxicity in mouse brain is attenuated by ketoprofen, a non-steroidal anti-inflammatory drug.

We examined effects of non-steroidal anti-inflammatory drugs (NSAIDs) on methamphetamine (METH)-induced neurotoxicity. Marked reduction of dopamine transporter-positive signals and accumulation of microglial cells in the striatum after METH injections (4 mg/kg x4, i.p. with 2 h-interval) were significantly and dose-dependently attenuated by four injections of ketoprofen (2 or 5 mg/kg x4, s.c.) given 30 min prior to each METH injection, but not by either a low or high dose of aspirin. The present results suggest that the protective effects of ketoprofen against METH-induced neurotoxicity and microgliosis might be based on its inhibitory activity on inflammatory response or on microglia activation, but not on its cyclooxygenase-inhibiting property. This provides a possible new strategy against METH-induced neurotoxicity using commonly used NSAIDs.

Animals↗
PubMed2003

Microwave cell death: Enzyme histochemical evaluation for metastatic carcinoma of the liver.

We have reported that microwave cell death is a unique cell death preserving not only cell and nuclear shapes but also immunohistochemical antigenicity. However, their enzyme activity was lost, which indicated cell dysfunction and death. This peculiar observation implies that the microwave effect is likely an 'in situ' tissue fixation and that this type of cell death is morphologically different from cell death, by either oncosis or apoptosis, as previously known. To confirm whether this peculiar cell death was observed also in human tissue samples, we examined clinical samples from patients with metastatic liver cancer, which were treated with microwave irradiation. They were examined immunohistochemically for human Ki-67 antigen and proliferating cell nuclear antigen and enzyme histochemically for alkaline phosphatase, and the same morphological changes that were observed in microwave-treated rat liver were found. In conclusion, we believe that routine hematoxylin-eosin stain alone is not a suitable method to evaluate microwave treatment for cancer because microwave coagulation therapy-treated cells preserved their nuclei and cellular architectures, even after 3 months. For microwave-treated tumors, enzyme histochemistry is helpful to determine its effectiveness.

Aged↗
PubMed2003

[Combined determination of urine uracil levels and plasma 5-FU clearance for a simple order-made treatment with anticancer agents of FU derivative].

Individual differences exist in the pharmacodynamics of fluorouracil-derived anticancer agents, with circadian variability even in the same patient probably due to individual differences in the distribution of dihydrophrimidine dehydrogenase (DPD), a decomposing enzyme. Though DPD activity is usually determined in the liver or blood, a more simplified estimation of DPD activity has been recently attempted using urine uracil levels. However, because urine uracil level has the drawback of being easily affected by food ingestion or kidney function, in this study it was determined simultaneously with the determination of plasma 5-FU clearance after sustained instillation of 250 mg 5-FU, in order to estimate DPD activity more accurately. A correlation was observed between urine uracil levels and 5-FU clearance. In cases showing a baseline urine uracil level below 25.1 mumol/g. Creatinine, the blood concentration decreased due to large 5-FU clearance, with a tendency for diminished efficacy of FU-derived anticancer agents. In cases showing a baseline urine uracil level above 99.9 mumol/g. Creatinine, on the other hand, adverse reactions due to FU anticancer agents tended to become more serious. Since urine uracil level can be determined easily, it could be the first choice in screening to detect abnormal metabolism of fluorouracil-derived anticancer agents under present circumstances. By combining determination of urine uracil level with 5-FU clearance, it seems possible to predict adverse effects and the effective rate of these agents more accurately. Under existing circumstances, where genetic analysis remains unavailable as a general practice, the combined determination of urine uracil levels and plasma 5-FU clearance may be beneficial in developing order-made treatments in cancer chemotherapy.

Adult↗
PubMed2003

[New aspects of neuroprotective effects of nonsteroidal anti-inflammatory drugs].

Nonsteroidal anti-inflammatory drugs (NSAIDs) exert anti-inflammatory, analgesic and antipyretic activities and are involved in the suppression of prostaglandin synthesis by inhibiting cyclooxygenase (COX), a prostaglandin synthesizing enzyme. It has been recently revealed that NSAIDs also possess inhibitory effects on the generating system of nitric oxide radicals and modulating effects on transcription factors and nuclear receptors which are related to inflammatory reactions. Since it has been reported that inflammatory processes are associated with the pathophysiology of several neurodegenerative diseases and that NSAIDs inhibit amyloid beta-protein-induced neurotoxicity to reduce the risk for Alzheimer's disease, a number of studies have been conducted focusing on the neuroprotective effects of NSAIDs. It has been clarified that the drugs exert neuroprotective effects, which are not related to their COX-inhibiting property, on pathophysiology of various neurological disorders. In this article, new aspects of neuroprotective effects of NSAIDs have been reviewed, especially, in Alzheimer's disease and Parkinson's disease, discussing various pharmacological effects of NSAIDs other than their inhibitory action on COX.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2003

[Support of TS-1, 5-FU preparation containing potent DPD inhibitor by determination of urinary uracil/serum 5-FU clearance].

Though FU-derived anticancer agents are metabolized and detoxicated by dihydropyrimidine dehydrogenase (DPD), its wide distribution of activity is concerned primarily in the antitumor effects or side effects of 5-FU. In recent years, it has become possible to predict the metabolism of FU-derived anticancer agents by DPD activity through the determination of urinary uracil levels. In the present study, therefore, we examined whether or not urinary uracil levels could be used as a predictor for as certaining the efficacy and/or side effects of TS-1, which contains a potent DPD inhibitor. Consequently, the following relationship was revealed to exist between urinary uracil levels and clinical effects of TS-1: 1) The effect of TS-1 administration was generally good in patients whose uracil level was within the standard values with no presentation of serious side effects. 2) The administration of TS-1 was also useful even in patients whose uracil levels were below the standard value. 3) Though no side effects were observed when a conventional FU-derived anticancer agent was administered to patients showing an urinary uracil level below the standard value, some side effects appeared when TS-1 was administered. Under present circumstances where understanding of genome diagnosis and establishment of informed consent are rather difficult, this approach of predicting DPD activities through the determination of urinary uracil levels seems to be of help for deciding a therapeutic regimen based on the patient's constitutional features when a cancer chemotherapy with TS-1 is performed.

Adult↗
PubMed2002

[Microwave coagulation therapy for unresectable colorectal metastatic liver tumor].

INTRODUCTION: We evaluate the utility of microwave coagulation therapy (MCT) for the patients with unresectable liver metastasis from colorectal cancers. METHODS: Forty-four patients unresectable synchronous colorectal hepatic metastasis between January 1, 1989 and December 31, 2000, were enrolled in the present study. The patients courses were followed until March, 2002. To evaluate the efficacy of MCT for unresectable liver metastasis from colorectal cancers, a retrospective comparative study was done between a MCT with CT (hepatic arterial trans-infusion chemotherapy and/or systemic chemotherapy) group and a CT group. The background factors were examined included the maximum tumor diameter, the number of liver metastasis and disease of other metastatic sites, which influenced the outcome. RESULTS AND CONCLUSION: The survival curves of the patients with unresectable synchronous colorectal hepatic metastasis undergoing MCT with CT and CT alone were significantly different (p = 0.03). No significant differences were found in the background factors that had a prognostic influence. It is confirmed that using MCT can prolong the survival rate for the patients with unresectable synchronous colorectal hepatic metastasis.

Antineoplastic Agents↗
PubMedDate not supplied

Endoscopic microwave coagulation therapy of postoperative hemorrhage from a stapled anastomosis.

We experienced three cases of postoperative hemorrhage from a stapled gastrointestinal anastomosis, and established endoscopic microwave coagulation therapy (EMCT) with a cylinder-type electrode. We were able to treat postoperative hemorrhage over the entire circumference of stapled anastomosis successfully. Two patients had undergone a lower third thoracic esophagogastrectomy through a left thoraco-abdominal approach for gastric cancer in the cardia, while the other case had undergone Billroth I gastrectomy. They each had fresh bleeding from the stapled anastomosis after the operation. Emergency endoscopic examination was immediately performed. Endoscopy revealed bleeding on the suture line. We performed hemostasis endoscopically with microwave coagulation therapy safely. They were discharged from the hospital without complications such as leakage and stenosis. Since EMCT with the cylinder-type electrode can coagulate shallowly and widely, it is very effective for hemorrhage from a stapled anastomosis.

Aged↗