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Biomedical subjects

Tohru Takahashi

Publications and source records attributed to Tohru Takahashi.

At least 19 recordsLinked to original sources
PubMed2006

[Basic evaluation of the new pulse sequence for simultaneous acquisition of T1- and T2-weighted images].

A novel pulse sequence that enables simultaneous acquisition of T1-weighted (T1W) and T2-weighted (T2W) images is presented. In this new technique, the inversion recovery (IR) pulse of conventional fast inversion recovery (Fast IR) is replaced with a pulse train that consists of a fast spin echo (FSE) and 180 (y) +90 (x) for driven inversion (DI). By using a shorter TI and independent k-space ordering, the first part of the sequence provides T2W images and the second part provides T1W images, thereby enabling simultaneous acquisition in a single scan time comparable to that of Fast IR. Signal simulation also was conducted, and this was compared with conventional scanning techniques using normal volunteers. In the human studies, both T1W and T2W images showed the same image quality as conventional images, suggesting the potential for this technique to replace the combination of Fast IR and T2W FSE for scan-time reduction.

Adult↗
PubMed2006

Novel metal-free hydrogenation of the carbon-carbon double bond in azulenoid enones by use of cycloheptatriene and protic acid.

[reaction: see text] An efficient method for the hydrogenation of the carbon-carbon double bond in azulenoid and aromatic fused azulenoid enones without the use of hydrogen and a metal catalyst is reported. Treatment of a variety of azulenoid enones with cycloheptatriene and a protic acid in acetonitrile gave the corresponding beta-azulenyl ketone derivatives in excellent to moderate yield. In this reaction, cycloheptatriene acts as a hydride donor.

Journal Article↗
PubMed2006

Correlation between glial fibrillary acidic protein-positive astrocytes and age in the human hippocampus.

The hippocampus is one of the areas most vulnerable to histopathological changes, and such changes may yield useful information in forensic medicine. We found that glial fibrillary acidic protein (GFAP)-positive astrocytes are frequently found in the hippocampus of consecutive series of forensic brains, distributed predominantly in the hippocampal CA4 and hippocampal sulcus (HS) regions. The present study counted GFAP-positive astrocytes in these regions and investigated associations with age, cause of death and postmortem time. Significant correlations were found between age and number of GFAP-positive astrocytes in both CA4 and HS regions. Number of GFAP-positive astrocytes increases in an age-dependent manner, but no correlations were noted between number of GFAP-positive astrocytes and postmortem time and cause of death. Number of GFAP-positive astrocytes in the hippocampus may provide useful information for age estimation.

Adolescent↗
PubMed2006

New ambulatory implant technique of high-dose-rate interstitial brachytherapy for prostate cancer.

PURPOSE: The aim of this study was to improve the performance status of prostate cancer patients during high-dose-rate interstitial brachytherapy (HDR-ISBT). To this end, we have developed a new ambulatory implant technique. MATERIALS AND METHODS: Ten prostate cancer patients were treated with HDR-ISBT as monotherapy from October 2003 until March 2004. We utilized a new removable template, a flexible applicator with a nonmetallic bead and button stopper, and an inner catheter connecting the applicator and the transfer tube of the brachytherapy unit. We shortened the connector end of the flexible applicator to enable the patient to sit down and walk freely during the treatment time. RESULTS: All 10 patients could walk without any support. No problem in the application was observed. CONCLUSION: Our new ambulatory implant technique for HDR-ISBT was able to improve the performance status of prostate cancer patients.

Aged↗
PubMed2006

Brain processing of audiovisual sexual stimuli inducing penile erection: a positron emission tomography study.

PURPOSE: Penile erection is dependent on commands from the central nervous system. Although basic studies of animals and neuroimaging studies of humans have been conducted to identify key brain regions associated with sexual arousal, to our knowledge no reliable studies of the first excitation phase of sexual arousal leading to penile erection have been reported. MATERIALS AND METHODS: We used H(2)(15)O-positron emission tomography to analyze regional cerebral blood flow just before penile erection in heterosexual volunteers. The subjects viewed 3 different types of audiovisual materials-sexually explicit clips, nonsexual neutral clips and dynamic mosaic image control clips-presented in random order, and penile rigidity was monitored in real time with a RigiScan(R) Plus device. Positron emission tomography scanning was initiated simultaneously when each clip was started, and images obtained when the subjects showed appropriate penile response were analyzed and compared. RESULTS: The advanced audiovisual cortices and cerebellar vermis in the right hemisphere were activated for sexually explicit-dynamic mosaic image control clip contrast, and only the right middle frontal gyrus was activated for sexually explicit- nonsexual neutral clip contrast. Several primary visual and audio regions were activated for dynamic mosaic image control-sexually explicit clip contrast and nonsexual neutral-sexually explicit clip contrast. CONCLUSIONS: We speculate that advanced audiovisual activity with imagination, not primary visual and audio activity, occurs when men experience sexual arousal inducing penile erection. Furthermore, the cerebellar vermis may be a key region for induction of penile erection in humans.

Acoustic Stimulation↗
PubMed2006

Cancer and pulmonary embolism: thrombotic embolism, tumor embolism, and tumor invasion into a large vein.

BACKGROUND: The specific incidence of thrombotic pulmonary embolism (PE), tumor PE and tumor invasion into large veins according to tumor type and tumor site remains unclear. METHODS AND RESULTS: A total of 65,181 cancer patients were identified from 98,736 postmortem examinations. Thrombotic PE occurred in 2.32% of all cancer patients and comprised 88.6% of the total number of all PE events. The incidence of thrombotic PE was high in those with adenocarcinoma, leukemia and large cell carcinoma, and was low in those with hepatic cell carcinoma. The incidence of PE was high when tumor was present in hematogenous tissue, lungs, ovaries, pancreas and the biliary system, and was low when tumor was present in the liver. The incidence of tumor PE was high with large cell carcinoma, hepatic cell carcinoma and adenocarcinoma, and was also high when tumor was present in the lungs, ovaries, kidneys and liver. There was a significant correlation between the incidence of tumor PE and the incidence of tumor invasion into large veins. CONCLUSION: The incidence of thrombotic PE, tumor PE and tumor invasion into large veins varies significantly according to tumor histopathology and tumor site.

Adolescent↗
PubMed2005

Increased [18F]fluorodeoxyglucose accumulation in right ventricular free wall in patients with pulmonary hypertension and the effect of epoprostenol.

OBJECTIVES: We examined whether right ventricular (RV) [(18)F]fluorodeoxyglucose (FDG) accumulation is increased in patients with pulmonary hypertension using gated positron emission tomography (PET) and whether RV FDG accumulation changes after therapy with epoprostenol. BACKGROUND: Myocardial glucose utilization is increased in animal models with ventricular pressure overload. METHODS: We performed gated FDG-PET in 24 patients with pulmonary hypertension. The RV standardized uptake value (SUV) of FDG was corrected for the partial volume effect based on the wall thickness measured by electron-beam computed tomography or magnetic resonance imaging. RESULTS: The corrected RV SUV of FDG was significantly correlated with the pulmonary vascular resistance, mean pulmonary artery pressure, right atrial pressure, RV wall stress, and plasma brain natriuretic peptide levels, but not with the RV wall thickness and mass. After pulmonary vasodilator therapy with epoprostenol for three months, the corrected RV SUV of FDG significantly decreased in the responders, but not in the non-responders, and the percentage change of the corrected RV SUV of FDG was significantly correlated with the percentage change of the pulmonary vascular resistance (r = 0.78; p < 0.01) and RV systolic wall stress (r = 0.76; p < 0.05). CONCLUSIONS: The RV FDG accumulation corrected for the partial volume effect was significantly increased in accordance with the severity of the RV pressure overload (i.e., the RV peak-systolic wall stress) in patients with pulmonary hypertension. Furthermore, the corrected RV FDG accumulation was decreased after the treatment with epoprostenol in accordance with the degree of reduction in the pulmonary vascular resistance and RV peak-systolic wall stress.

Antihypertensive Agents↗
PubMed2005

Gastric small cell carcinoma with marked response to neoadjuvant chemotherapy.

We report a patient with gastric small cell carcinoma (SCC) who showed a marked response to neoadjuvant chemotherapy. The patient was a 72-year-old Japanese man who was admitted because of epigastralgia. Subsequent examination revealed the presence of advanced gastric carcinoma in the lesser curvature of the lower body of the stomach, with multiple abdominal lymph node metastases. Endoscopic biopsy specimens from the tumor revealed SCC with moderately differentiated adenocarcinoma. The patient received neoadjuvant chemotherapy consisting of carboplatin (400 mg/m2, for 1 day), epirubicin (27 mg/m2, for 1 day), etoposide (70 mg/m2, for 3 days), and 5-fluorouracil (330 mg/m2, for 11 days). Clinically, the primary tumor and lymph node metastases were markedly reduced. Subsequently the patient underwent curative surgery and was alive without recurrence for more than 3 years after the surgery.

Aged↗
PubMed2005

Portopulmonary hypertension: hemodynamics, pulmonary angiography, and configuration of the heart.

BACKGROUND: The goal of the present study was to examine the cardiac configuration and pulmonary vascular changes in patients with portopulmonary hypertension (PPHTN) and compare them with those of idiopathic pulmonary arterial hypertension (IPAH). METHODS AND RESULTS: The subjects were 10 patients with PPHTN and 18 with IPAH. In PPHTN, the increases in the right ventricular end-diastolic volume index (89+/-19 vs 128+/-50 ml/m2; p=0.04), right end-systolic volume index (50+/-19 vs 95+/-47 ml/m 2; p=0.02) and right ventricular mass index (47+/-18 g/m2 vs 79+/-31; p=0.04) were low compared with IPAH. The decrease in the right ventricular ejection fraction was also low in PPHTN (45+/-10 vs 28+/-13%; p=0.01). The degree of sparse arborization and abrupt narrowing on wedged pulmonary angiography was moderate in PPHTN compared with IPAH. In PPHTN, the proximal pulmonary arteries were dilated near the segmental arteries, which were narrow in IPAH. CONCLUSION: Changes in the configuration of the heart were moderate in PPHTN compared with those in IPAH. The degree of sparse arborization and abrupt narrowing were also moderate in PPHTN.

Adult↗
PubMed2005

Efficacy of acute inhalation of nitric oxide in patients with primary pulmonary hypertension using chronic use of continuous epoprostenol infusion.

BACKGROUND: There have only been a few reports published on combination therapy for patients with primary pulmonary hypertension (PPH). METHODS AND RESULTS: Fifteen patients with PPH (4 men and 11 women, 34.5+/-12.1 years old) had received chronic administration of epoprostenol and the additive effects of inhaled nitric oxide (NO) and the hemodynamic changes were evaluated. In addition, the difference in the effect of acute NO loading before and after the epoprostenol therapy was compared in 6 of these patients. Under chronic use of epoprostenol, mean pulmonary arterial pressure, mean right atrial pressure and pulmonary vascular resistance were decreased with acute inhalation of NO. However, cardiac output, mean aortic pressure and systemic vascular resistance were unchanged. As a result, the pulmonary to systemic vascular resistance ratio was reduced. Moreover, after chronic use of epoprostenol, the change (delta) in cardiac output with NO inhalation was increased and the NO-induced decrease in pulmonary vascular resistance was augmented compared to those before the induction. CONCLUSION: Nitric oxide inhalation further improved the hemodynamics when combined with chronic use of epoprostenol in PPH patients. These results suggest the possibility that combination therapies can be used in the treatment for PPH patients.

Administration, Inhalation↗
PubMed2005

Acute renal failure likely due to acute nephritic syndrome associated with typhoid fever.

A 45-year-old woman was admitted to our hospital because of high fever and malaise. She also presented abnormal urine findings including macrohematuria and proteinuria with transient renal insufficiency. Salmonella Typhi was isolated from her blood and stool culture, and then she was diagnosed as having typhoid fever. Salmonella enterica serotype typhi infection can be complicated by renal involvement, although rare. In Japan, few cases have been reported about acute nephritic syndrome in typhoid fever. Here, we report a case of endemic acquired typhoid fever associated with acute renal failure probably due to acute nephritic syndrome successfully treated with levofloxacin.

Acute Disease↗
PubMed2005

[Prostate cancer metastasized to thyroid cartilage: a case report].

A 75-year-old male was diagnosed as prostate cancer (serum PSA: 4,772 ng/ml, Gleason score: 4 + 4 = 8) with multiple bone metastases. And he noticed a painless mass of the frontal neck a month before the diagnosis. Computed tomography of the neck showed a tumor in the thyroid cartilage. Biopsy of the neck tumor revealed metastasis of prostate cancer by positive PSA staining. Metastasis of malignant tumor to cartilaginous tissue is extremely rare because there are usually no vessels in it. Only 4 cases of the metastasis of prostate cancer to the thyroid cartilage have been reported. It was thought that tiny bone marrows were formed in the ossified cartilage and it caused hematogenous metastasis.

Adenocarcinoma↗