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Shoki Takahashi

Publications and source records attributed to Shoki Takahashi.

At least 37 records · Page 2Linked to original sources
PubMed2005

The effects of copper-histidine therapy on brain metabolism in a patient with Menkes disease: a proton magnetic resonance spectroscopic study.

We report on metabolic changes in the brain of a boy with Menkes disease. He was treated with parenteral copper (Cu)-histidine supplementation, from 5 months of age, and assessed with proton magnetic resonance spectroscopy ((1)H-MRS). The single-voxel (1)H-MRS before treatment revealed an accumulation of lactate and a reduced N-acetyl aspartate (NAA)/total creatine (tCr) ratio with a z-score of -3.0. During treatment, the lactate signal faded away, whereas the NAA signal gradually increased to a z-score of -1.5 at 120 days of treatment. The choline/tCr ratio did not deviate much initially (z-score +0.5), but the ratio increased markedly during treatment (z-score +4.8). Consequently, the Cu-histidine therapy initiated after the critical period still improved the neuronal metabolism, suggesting that some Cu was delivered to neurons. Nevertheless, the brain atrophy, impaired myelination, and severe neurological symptoms were not ameliorated.

Brain↗
PubMed2005

Time-related changes in computed tomographic appearance and pathologic findings after radiofrequency ablation of the rabbit lung: preliminary experimental study.

PURPOSE: To evaluate correlations between computed tomographic (CT) appearance and pathologic findings after radiofrequency (RF) ablation of lungs and to determine whether CT appearance could predict the extent of the effective therapeutic area. MATERIALS AND METHODS: The lungs of 14 rabbits were subjected to RF ablation and CT scans were obtained immediately and at various intervals thereafter. Four rabbits were killed immediately after the initial CT imaging (n = 4). The remaining 10 rabbits were killed after additional CT scans at intervals of 3 days (n = 2), 1 week (n = 4), 2 weeks (n = 2), and 3 weeks (n = 2) after RF ablation. Pathologic findings were correlated with CT appearance. RESULTS: Immediately after RF ablation, a restricted area of central dense opacity enclosed by an extensive area of ground-glass opacity was noted in the ablated region on CT images. Pathologically, the former corresponded to destructive tissue and the latter corresponded to tissue with some degree of injury. After 1 week, the entire ablated region appeared as a well-demarcated homogeneous dense opacity on CT that corresponded to necrotic tissue and its surrounding rim of granulation tissue on histopathologic examination, indicating that the enclosing extensive area of ground-glass opacity on the initial CT scan represented an ongoing necrosis. Within 2-3 weeks, the ablated region gradually contracted on the CT images, representing a tissue repairing process in which the granulation tissue was encroaching on the inner necrotic tissue. CONCLUSION: Ground-glass opacity of the ablated region on CT immediately after RF ablation represents an ongoing necrosis.

Animals↗
PubMed2005

3beta-Hydroxysteroid dehydrogenase in human aorta.

3beta-Hydroxysteroid dehydrogenase (3beta-HSD) is known to be involved in steroid production and/or metabolism and to be expressed in many tissues including adrenal cortex. Expression of this enzyme has also been elucidated in human cardiovascular system but its details remain largely unknown. Therefore, in this study, we examined the status of 3beta-HSD in postmortem human aorta utilizing RT-PCR and immunohistochemical analysis. Both mRNAs and immunoreactivity for the enzyme were detected predominantly in female aorta, and in those with mild atherosclerotic changes. In addition, immunohistochemical study demonstrated that immunoreactivity for 3beta-HSD was detected in vascular smooth muscle cells (VSMCs) of aorta. These findings all indicated that steroidogenesis via 3beta-HSD may occur in VSMCs of human aorta, possibly related to gender differences and/or the degree of atherosclerosis.

3-Hydroxysteroid Dehydrogenases↗
PubMed2005

Progesterone receptor subtypes in vascular smooth muscle cells of human aorta.

Progesterone is involved in various functions of the cardiovascular system, including those of vascular smooth muscle cells (VSMCs) via progesterone receptor (PR). Progesterone has also been postulated to be involved in inhibition of VSMC proliferation via PR. However, the details of PR expression have remained largely unknown in human cardiovascular VSMCs. Therefore, we first examined the relative levels of PR isoform (PR-A and PR-B) expression in VSMCs, using both immunohistochemistry and quantitative RT-PCR analysis. PR-B was equally expressed between male and female aorta, but PR-A was more abundant in female than in male aorta. This finding demonstrated that the status of PR subtype expression was associated with the difference of genders.

Adult↗
PubMed2005

In situ androgen producing enzymes in human prostate cancer.

Androgens have been proposed to be actively produced in situ in human prostate cancer. These locally produced androgens have also been considered to play important roles in the pathogenesis and development of prostate cancer. Therefore, it is important to examine the status of this in situ androgen metabolism and/or synthesis in detail in order to improve the clinical response to hormonal therapy in patients diagnosed with prostate cancer. Several studies have previously demonstrated the expression of androgen-producing enzymes such as 5alpha-reductase types 1 and 2, and 17beta-hydroxysteroid dehydrogenase type 5 (17beta-HSD5), in human prostate carcinoma cells. However, their biological significance has remained largely unknown. In this study, we evaluated the immunoreactivities of these steroidogenic enzymes in human prostate cancer obtained from surgery (n = 70), and correlated the findings with clinicopathological features of the patients. 17Beta-HSD5 immunoreactivity was detected in 54 cases (77%), 5alpha-reductase type 1 in 51 cases (73%) and 5alpha-reductase type 2 in 39 cases (56%). 5Alpha-reductase type 2 immunoreactivity was significantly correlated with that of androgen receptor (AR), and 17beta-HSD5 positive cases were significantly associated with clinical stage (TNM stage pT3 vs pT2). These data all suggest that androgen-producing enzymes, such as 5alpha-reductase type 1 and type 2, and 17beta-HSD5 are expressed in a majority of prostate cancers, and are involved in the local production and actions of androgens in prostate cancers.

17-Hydroxysteroid Dehydrogenases↗
PubMed2005

Systemic to pulmonary venous shunt in lung cancer with obstruction of superior vena cava: case report with review of the literature.

We describe the CT features of an unusual collateral pathway of systemic to pulmonary venous shunt in a patient with lung cancer that obstructed the superior vena cava (SVC). Spiral CT scan with rapid injection of contrast medium from a right arm vein revealed a systemic to pulmonary venous shunt (SPVS), passing through thick pleural effusion, which was the direct transpleural communication between right upper chest wall veins and right superior pulmonary veins. Three-dimensional CT angiography revealed the entire shunt. We consider that the shunt was formed in association with radiation therapy, and was not injured with the subsequent collapse of the lung and accumulation of massive pleural effusion. We review the reports that have dealt with the shunt in patients with lung cancer, and discuss the conditions related to the development of SPVS in such patients.

Heart Defects, Congenital↗
PubMed2005

Long-term outcome of breast-conserving therapy for breast cancer.

PURPOSE: We present a retrospective analysis of long-term therapeutic results for patients treated in our institution to evaluate the efficacy of breast-conserving therapy (BCT). PATIENTS AND METHODS: The study population was 99 patients (102 breasts) with stage 0, I, and II breast cancer who underwent breast conservation therapy between April 1990 and November 1997. The entire breast was irradiated to a median dose of 50 Gy (range, 50-60 Gy) in 25-30 fractions. An additional 10 Gy in five fractions with 6-12 MeV electrons was given to 23 breasts (23%) with positive surgical margins. RESULTS: The 5-/10-year overall survival, cause-specific survival, relapse-free rate, local recurrence, and regional recurrence rates were 94.6/93.3%, 95.7/94.5%, 88.2/77.5%, 4.2/8.5%, and 2.0/6.3%, respectively. In both uni- and multivariate analyses, age < 40 years was a significant prognostic factor for local recurrence. No severe morbidity was observed. CONCLUSION: The long-term clinical outcome of BCT for early breast carcinoma patients in our department was favorable. Patient age <40 was the most important factor associated with an increased risk of local recurrence in the ipsilateral breast.

Adult↗
PubMed2004

Changes in brain activation associated with use of a memory strategy: a functional MRI study.

It has been confirmed that some kinds of what are called memory strategies dramatically improve the performance of memory recall. However, there has been no direct research to examine changes in brain activity associated with the use of the method of loci within individuals. In the present study, using fMRI, we compared brain activations before and after instruction in the method of loci during both the encoding and recall phases. The resulting behavioral data showed that the use of the method of loci significantly increased scores for memory recall. The imaging data showed that encoding after instruction in the method of loci, relative to encoding before it, was associated with signal increases in the right inferior frontal gyrus, bilateral middle frontal gyrus, left fusiform gyrus, and bilateral lingual gyrus/posterior cingulate gyrus. Comparison of recall after instruction in the method of loci with that before it showed significant activation in the left parahippocampal gyrus/retrosplenial cortex/cingulate gyrus/lingual gyrus, left precuneus, left fusiform gyrus, and right lingual gyrus/cingulate gyrus. The present study demonstrated the changes in brain activation pattern associated with the use of the method of loci; left fusiform and lingual activity was associated with both the encoding and recall phases, bilateral prefrontal activity with the encoding phase, and activity of the posterior part of the parahippocampal gyrus, retrosplenial cortex, and precuneus with the recall phase. These findings suggest that brain networks mediating episodic encoding and retrieval vary with how individuals encode the same stimuli.

Adult↗
PubMed2004

Spiegel's lobe bile ducts often drain into the right hepatic duct or its branches: study using drip-infusion cholangiography-computed tomography in 179 consecutive patients.

Using drip-infusion cholangiography-computed tomography (DIC-CT), we successfully identified the bile ducts draining the caudate lobe in 138 of 179 consecutive patients with extrahepatic cholelithiasis (179 ducts from Spiegel's lobe and 154 from the paracaval portion; 1-5 ducts per patient). The dorsal subsegmental duct of S8 (B8c) was often identified and could be discriminated from the paracaval caudate ducts, thus acting as a landmark for the right margin of the caudate lobe. Notably, in more than one-third of the 138 patients, at least one of the Spiegel's lobe ducts drained into the right hepatic duct or its branches (30.2% of the 179 ducts overall; all ducts joined branches of the right lobe in 25 patients). Similarly, 34.4% of the 154 paracaval caudate lobe ducts drained into the left hepatic duct or its branches. These "anatomical left/right dissociations" between the drainage territory and route were much more frequent than previously reported. Our results confirm the effectiveness of DIC-CT as a classical, noninvasive method for presurgical evaluation of the biliary system, but they also suggest that anatomical partial resection of the dorsal liver in patients with hilar cholangioma is often impossible because of contralateral biliary drainage.

Adolescent↗
PubMed2004

Pseudoaneurysm of the inferior epigastric artery successfully treated by ultrasound-guided compression.

An 82-year-old woman underwent right hemicolectomy by median laparotomy. Two weeks later, a pulsatile mass was found at the left side of the surgical wound, which was diagnosed as pseudoaneurysm of the inferior epigastric artery by color Doppler US and CT. The pseudoaneurysm was successfully treated by US-guided compression of the neck of the aneurysm for 30 minutes. US-guided compression should be considered the treatment of choice for postsurgical pseudoaneurysm of the inferior epigastric artery.

Aged↗
PubMed2004

Estrogen receptors in atherosclerotic human aorta: inhibition of human vascular smooth muscle cell proliferation by estrogens.

Estrogen has been postulated to exert direct anti-atherogenic effects via binding to estrogen receptors (ERs) in vascular smooth muscle cells (VSMCs). Therefore, we believe it is important to examine the status of ER expression in the human cardiovascular system and its disorders. In this study, we first evaluated the relative abundance of messenger RNA (mRNA) of both ER subtypes (ERalpha and ERbeta) in the human aorta using reverse transcription followed by quantitative polymerase chain reaction (RT-qPCR). We then examined the immunolocalization of both ERs in VSMCs of human atherosclerotic lesions. In order to examine which ER subtype was associated with the anti-atherogenic effects of estrogen, we examined the effects of estrogen in two VSMC cell lines, one positive only for ERalpha and the other positive only for ERbeta. The relative abundance of mRNAs for both ERs was higher in female aorta with a mild degree of atherosclerosis than in female aorta with a severe degree of atherosclerosis (P < 0.05). In addition, the number of ERalpha and/or ERbeta double positive cells in the neointima was higher in female aorta with a mild degree of atherosclerosis than in female aorta with severe atherosclerosis (P < 0.05). Our in vitro study found that estradiol was able to significantly inhibit the proliferation of ERalpha positive VSMCs but not ERbeta positive VSMCs (P < 0.05). Moreover, estradiol was found to significantly suppress proliferating cell nuclear antigen (PCNA) mRNA levels in ERalpha positive VSMCs compared to that of ERbeta positive VSMCs, consistent with the findings of cell proliferation. Results from this study suggest that estrogens can inhibit the proliferation of VSMCs through ERalpha, especially in pre-menopausal women. Our study also indicates that decreased levels of ER, especially ERalpha, in the female atherosclerotic neointima may be associated with progression of atherosclerotic changes.

Actins↗
PubMed2004

Periampullary tumors: high-spatial-resolution MR imaging and histopathologic findings in ampullary region specimens.

PURPOSE: To prospectively determine the magnetic resonance (MR) signal intensity characteristics of structures of the ampullary region and to assess the potential use of MR imaging in evaluation of the extent of periampullary tumors in resected specimens. MATERIALS AND METHODS: Twenty-five specimens from the ampullary region obtained in four autopsy cases without periampullary tumors and in 21 patients with periampullary tumors were examined with a 1.5-T MR system and a circular surface coil with 5-inch (12.7-cm) diameter. High-spatial-resolution MR images were obtained with field of view of 100 x 100 mm, matrix of 256 x 256 or 512 x 256, and section thickness of 2 mm. MR imaging findings were compared with histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissues were evaluated by two radiologists. RESULTS: T1- and T2-weighted MR images clearly depicted normal structures in the ampullary region that included Oddi muscle, duodenal wall, common bile duct, and pancreas; these findings corresponded well with histologic findings. In 20 (95%) of 21 tumors, high-spatial-resolution MR imaging depicted location and extension of periampullary tumors precisely. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissue were 88%, 100%, 96%, 100%, and 94%, respectively. CONCLUSION: In this study, MR imaging correctly depicted location, extension, and origin of tumor. High-spatial-resolution MR imaging has potential for presurgical staging of tumors in this region.

Aged↗
PubMed2004

Usefulness of asialoglycoprotein receptor imaging for the evaluation of liver metastasis of neuroblastoma.

Neuroblastoma, derived from the neural crest ectoderm, is the most common type of solid abdominal mass seen in infancy. The diagnosis, staging, and follow-up of neuroblastoma are often performed using metaiodobenzylguanidine (MIBG) imaging. However, the evaluation of liver metastasis by this method is complicated by the normal physiological uptake of MIBG by the liver. The asialoglycoprotein receptor is a hepatic cell-surface receptor specific for galactose-terminated glycoprotein, and 99mTc-DTPA-galactosyl human serum albumin (GSA) accumulates selectively in hepatic cells. Here, we report a case of congenital neuroblastoma with liver metastasis in which GSA scans were useful for differentiation between normal and metastatic sites in the liver.

3-Iodobenzylguanidine↗
PubMed2004

Scatter and cross-talk correction for one-day acquisition of 123I-BMIPP and 99mtc-tetrofosmin myocardial SPECT.

OBJECTIVE: 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and 99mTc-tetrofosmin (TET) are widely used for evaluation of myocardial fatty acid metabolism and perfusion, respectively. ECG-gated TET SPECT is also used for evaluation of myocardial wall motion. These tests are often performed on the same day to minimize both the time required and inconvenience to patients and medical staff. However, as 123I and 99mTc have similar emission energies (159 keV and 140 keV, respectively), it is necessary to consider not only scattered photons, but also primary photons of each radionuclide detected in the wrong window (cross-talk). In this study, we developed and evaluated the effectiveness of a new scatter and cross-talk correction imaging protocol. METHODS: Fourteen patients with ischemic heart disease or heart failure (8 men and 6 women with a mean age of 69.4 yr, ranging from 45 to 94 yr) were enrolled in this study. In the routine one-day acquisition protocol, BMIPP SPECT was performed in the morning, with TET SPECT performed 4 h later. An additional SPECT was performed just before injection of TET with the energy window for 99mTc. These data correspond to the scatter and cross-talk factor of the next TET SPECT. The correction was performed by subtraction of the scatter and cross-talk factor from TET SPECT. Data are presented as means +/- S.E. Statistical analyses were performed using Wilcoxon's matched-pairs signed-ranks test, and p < 0.05 was considered significant. RESULTS: The percentage of scatter and cross-talk relative to the corrected total count was 26.0 +/- 5.3%. EDV and ESV after correction were significantly greater than those before correction (p = 0.019 and 0.016, respectively). After correction, EF was smaller than that before correction, but the difference was not significant. Perfusion scores (17 segments per heart) were significantly lower after as compared with those before correction (p < 0.001). CONCLUSIONS: Scatter and cross-talk correction revealed significant differences in EDV, ESV, and perfusion scores. These observations indicate that scatter and cross-talk correction is required for one-day acquisition of 123I-BMIPP and 99mTc-tetrofosmin SPECT.

Aged↗
PubMed2004

Low-dose CT of the thorax in cancer follow-up.

PURPOSE: To evaluate the quality of low-dose computed tomography (CT) images in the follow-up of cancer patients. MATERIALS AND METHODS: We selected patients with urogenital (n = 7) or esophageal cancer (n = 13) who were attending routine follow-up between April and July 2001. After water and chest phantom studies to decide the scan parameters, postcontrast low-dose CT scans were obtained at 60 mA (45 mA s) with a smoothing kernel. Three radiologists reviewed the CT scans of the thorax independently for overall image quality and anatomic detail in both mediastinal and lung windows. They subjectively rated the images on a four-point scale (0: poor, 1: fair, 2: good, 3: excellent) according to graininess and sharpness. RESULTS: The average score of the low-dose CT for the lung window was 2.85, which was equivalent to control images. The average score for the mediastinal window was 1.77, which was lower than that of the control CT scan (2.62, P < 0.001) and almost identical to that of the chest phantom experiment. Nine of the 20 cases had abnormal findings; low-dose CT scans depicted them well and offered sufficient information for diagnosis. The radiation exposure was reduced by about half. CONCLUSION: The image quality of low-dose thoracic CT was satisfactory for both mediastinal and lung windows in the follow-up of cancer patients.

Aged↗
PubMed2004

E4F1, a novel estrogen-responsive gene in possible atheroprotection, revealed by microarray analysis.

Estrogen has been postulated to be involved in inhibition of vascular smooth muscle cell (VSMC) proliferation mainly via estrogen receptor (ER), but the detailed mechanism has remained primarily unknown. Therefore, in this study, microarray analysis was used in two types of cultured human VSMCs: one positive for ER alpha, and the other for ER beta, which were treated by estrogens to detect the estrogen-responsive genes. We also used quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate mRNA levels of selective target gene (TG) in these cells. We further studied whether the TG product was involved in inhibition of proliferation using small interfering RNA (siRNA) of the TG transfection. We subsequently used quantitative RT-PCR and in situ hybridization analysis to evaluate the expression of these gene products in human aorta. E4F1, a possible inducer of cell growth arrest, was markedly increased only in ER alpha-positive VSMCs by estrogens in both microarray and RT-PCR analyses. Blocking of E4F1 using siRNA suppressed estrogenic inhibition of ER alpha-positive VSMC proliferation. E4F1 mRNA was abundant in premenopausal female aorta with mild atherosclerotic changes. E4F1 is therefore considered one of the estrogen-responsive genes involving ER alpha-mediated inhibition of VSMC proliferation and may play an important role in estrogen-related atheroprotection of human aorta.

Adenovirus E4 Proteins↗
PubMed2004

MDCT compared with digital subtraction angiography for assessment of lower extremity arterial occlusive disease: importance of reviewing cross-sectional images.

OBJECTIVE: The aim of our study was to evaluate the efficacy of MDCT angiography in the assessment of lower limb peripheral arterial occlusive disease. MATERIALS AND METHODS: Twenty-four patients (representing 27 cases) with symptomatic lower extremity peripheral arterial occlusive disease underwent both MDCT angiography and digital subtraction angiography of the aortoiliac and lower extremity arteries. For data analysis, the arterial system was divided into 10 segments. Each segment was classified as normal, mildly stenotic, moderately stenotic, severely stenotic, or occluded. In evaluating MDCT angiographic findings, cross-sectional images were mainly observed by scrolling. The diagnostic accuracy of MDCT angiography was determined, using digital subtraction angiography as the standard reference. The extent of calcification in each segment was also assessed on MDCT angiography and was classified as absent, mildly calcified, or severely calcified. RESULTS: Of the 480 segments studied, 470 were assessable on both digital subtraction angiography and MDCT angiography. On digital subtraction angiography, 142 stenoocclusive segments (20 mildly stenotic, 14 moderately stenotic, 25 severely stenotic, and 83 occluded) were detected. With regard to the detection of segments that had more than mild stenosis, the sensitivity, specificity, and accuracy of MDCT angiography were 99.2%, 99.1%, and 99.1%, respectively. In the 421 noncalcified and mildly calcified segments, the sensitivity, specificity, and accuracy of MDCT angiography for the detection of more-than-mild stenosis were 100%, 100%, and 100%, respectively. CONCLUSION: MDCT angiography is a reliable method for evaluating the aortoiliac and lower extremity arteries.

Adolescent↗