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Tadashi Ishibashi

Publications and source records attributed to Tadashi Ishibashi.

At least 19 recordsLinked to original sources
PubMed2006

Chronic pancreatitis: MRCP versus ERCP for quantitative caliber measurement and qualitative evaluation.

PURPOSE: To retrospectively compare-in patients with chronic pancreatitis-magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) for measurement of main pancreatic duct (MPD) diameter by using area intensity measurement (AIM) at MRCP and full width at half maximum (FWHM) at ERCP and to retrospectively determine the accuracy of MRCP for depiction of pathologic changes by using ERCP as the reference standard. MATERIALS AND METHODS: The institutional review board approved this study and waived the need to obtain informed consent. Both MRCP and ERCP were performed in 24 patients with chronic pancreatitis (21 men, three women; mean age, 54 years +/- 14 [standard deviation]). The diameter of the MPD was determined by using both methods at the same sites in the head, body, and tail of the pancreas. MRCP and ERCP measurements involved AIM and FWHM techniques, respectively. For qualitative evaluation, visualization of the MPD and pathologic findings was also examined by using both methods. Paired t and Wilcoxon matched-pair signed rank tests were performed for the quantitative and qualitative evaluations, respectively. RESULTS: The mean diameter of the MPD at ERCP was 1.5 times larger, on average, than that at MRCP; differences were statistically significant for each segment, as well as for the entire duct system. For qualitative evaluation, MRCP tended to be superior to ERCP for delineation of the MPD. Overall sensitivity, specificity, and accuracy values of MRCP for delineating pathologic pancreatic changes were 88% (87 of 99), 98% (44 of 45), and 91% (131 of 144), respectively. CONCLUSION: Use of ERCP tends to result in overestimation of the caliber of the MPD. MRCP can enable accurate evaluation of the condition of the pancreatic duct and its changes in patients with chronic pancreatitis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed2005

Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes.

By analyzing 1,780,295 5'-end sequences of human full-length cDNAs derived from 164 kinds of oligo-cap cDNA libraries, we identified 269,774 independent positions of transcriptional start sites (TSSs) for 14,628 human RefSeq genes. These TSSs were clustered into 30,964 clusters that were separated from each other by more than 500 bp and thus are very likely to constitute mutually distinct alternative promoters. To our surprise, at least 7674 (52%) human RefSeq genes were subject to regulation by putative alternative promoters (PAPs). On average, there were 3.1 PAPs per gene, with the composition of one CpG-island-containing promoter per 2.6 CpG-less promoters. In 17% of the PAP-containing loci, tissue-specific use of the PAPs was observed. The richest tissue sources of the tissue-specific PAPs were testis and brain. It was also intriguing that the PAP-containing promoters were enriched in the genes encoding signal transduction-related proteins and were rarer in the genes encoding extracellular proteins, possibly reflecting the varied functional requirement for and the restricted expression of those categories of genes, respectively. The patterns of the first exons were highly diverse as well. On average, there were 7.7 different splicing types of first exons per locus partly produced by the PAPs, suggesting that a wide variety of transcripts can be achieved by this mechanism. Our findings suggest that use of alternate promoters and consequent alternative use of first exons should play a pivotal role in generating the complexity required for the highly elaborated molecular systems in humans.

Base Sequence↗
PubMed2005

Cutting balloon angioplasty of resistant renal artery stenosis caused by fibromuscular dysplasia.

Balloon angioplasty is an established intervention to treat renovascular hypertension. Conventional balloon angioplasty is usually effective in cases of renovascular hypertension caused by fibromuscular dysplasia. In the present report, we describe two cases of renovascular hypertension caused by fibromuscular dysplasia in which stenotic lesions were resistant to conventional balloon angioplasty but were successfully managed by a cutting balloon. After cutting balloon angioplasty, systemic blood pressure was normalized in both patients, without the use of antihypertensive agents. Angioplasty by using a cutting balloon is a new therapeutic choice against renal artery stenosis that is resistant to dilation by a conventional balloon.

Adolescent↗
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

Pancreatic ischemia associated with vasospasm in the early phase of human acute necrotizing pancreatitis.

OBJECTIVES: The angiographic appearance of acute necrotizing pancreatitis (ANP) demonstrates ischemic change with vasospasm in and around the pancreas. We investigated the role of vasospasm in pancreatic ischemia and necrosis in the early phase of human ANP. METHODS: The relationship between the angiographic abnormalities and the perfusion status of the pancreas documented by contrast-enhanced computed tomography (CE-CT) was examined in 102 patients with ANP who were admitted during the early phase of the disease. RESULTS: Ischemic change with vasospasm on angiography of the intrapancreatic and extrapancreatic arteries was observed and corresponded with the poorly perfused area of the pancreas detected by CE-CT done at admission. Resultant pancreatic necrosis was confirmed on follow-up CE-CT examination consistent with the location where angiography demonstrated ischemic change with vasospasm. Severe ischemic change on angiography was primarily observed in patients in whom more than 50% of the pancreas was poorly perfused. The extent of the ischemic change was correlated with the extent of the poorly perfused area of the pancreas and the mortality rate. CONCLUSION: These results suggest that vasospasm is involved in the development of pancreatic ischemia and necrosis in the early phase of ANP.

Adolescent↗
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↗
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

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

[Correlation between CT and pathological findings after radiofrequency ablation of rabbit lung: evaluation of therapeutic effective area].

The purpose of this study was to correlate the CT and pathologic findings after radiofrequency ablation (RFA) of rabbit lung and evaluate the therapeutically effective area. RFA was performed in eight rabbit lungs, and ablated regions were imaged immediately after RFA (n=8) and 1 week later (n=4). Immediately after RFA, the ablated regions showed ground-glass opacity. At one week, the ablated region showed very dense opacity, which corresponded to necrotic tissue. Ground-glass opacity signified the therapeutically effective area that would later turn into necrosis.

Animals↗
PubMed2004

[Peripheral venous stenoses of hemodialysis shunts: improved long-term patency rates with stent placement].

PURPOSE: The purpose of this study was to evaluate the effectiveness of endovascular stents placed in the peripheral veins of hemodialysis shunts. MATERIALS AND METHODS: 156 endovascular stents were placed in the peripheral veins of 155 hemodialysis shunts with 220 stenoses. Among these, 106 stenoses of 93 hemodialysis shunts had been treated by percutaneous transluminal angioplasty (PTA) before stent placement. RESULTS: The initial success rate was 97.7%. Primary radiologic patency rates of the stents at 6 months, 1 year, and 2 years were 69.8%, 49.1%, and 45.8%, respectively. Secondary radiologic patency rates at 1 year, 2 years, and 3 years were 94.0%, 91.8%, and 88.0%, respectively. Primary clinical patency rates at 6 months, 1 year, and 2 years were 64.4%, 43.4%, and 27.3%; while secondary clinical patency rates at 1 year, 2 years, and 3 years were 93.5%, 86.5%, and 73.4%, respectively. Radiologic and clinical primary patency rates of 106 stenoses and 93 hemodialysis shunts were significantly higher than those of PTA that had been performed before stents were placed. CONCLUSION: Stent placement for stenoses of the peripheral veins of hemodialysis shunts recurring in three months and treated by PTA alone can improve long-term patency.

Adult↗
PubMed2003

Complete sequencing and characterization of 21,243 full-length human cDNAs.

As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.

Chromosomes, Human, 21-22 and Y↗
PubMed2003

Steroid sulfatase and estrogen sulfotransferase in the atherosclerotic human aorta.

Various epidemiological studies have demonstrated a relatively low incidence of cardiovascular events in premenopausal women and its marked increment after menopause. In addition, estrogens have been postulated to exert direct anti-atherogenic effects via binding to estrogen receptors in vascular smooth muscle cells (VSMCs). However, not all postmenopausal women develop atherosclerosis despite decreased levels of serum estrogen. Therefore, we believe it is important to examine the status of estrogen metabolism in situ in the human cardiovascular system. Estrone sulfate (E1S) is a major circulating plasma estrogen that is converted into the biologically active estrogen, estrone (E1) by steroid sulfatase (STS). E1 is also sulfated and reverted into E1S by estrogen sulfotransferase (EST). These two enzymes have recently been shown to play important roles in the in situ estrogen actions of estrogen-dependent human tissues and various sex steroid-dependent tumors. STS and EST, however, have not been studied in detail in the human vascular system associated with atherosclerotic changes. In the present study, we evaluated the relative abundance of STS- and EST-immunoreactive protein and mRNA expression in human aorta using immunohistochemistry and reverse transcription followed by quantitative polymerase chain reaction in addition to enzyme activity. STS expression levels were found to be significantly higher in the VSMCs obtained from female aortas with mild atherosclerotic changes than in those with severe atherosclerotic changes and in male aortas regardless of atherosclerotic changes. EST expression levels in the VSMCs of these aortas, however, were significantly higher in female aortas with severe atherosclerotic changes and in male aortas than in female aortas with mild atherosclerotic changes. We believe it is important to examine factors regulating the expression and activity of these estrogen-metabolizing enzymes in the human aorta. Various cytokines have been proposed to function as regulators of these enzymes in other tissues. In the present study, we studied the effects of interleukin (IL)-1beta, known to be produced in human atherosclerotic lesions, on the expression of these enzymes using cultured human VSMCs originally obtained from a female patient. IL-1beta markedly inhibited the expression of STS mRNA and enzyme activity, but stimulated the expression of EST mRNA and enzyme activity. In addition, IL-1beta also reduced E2 production from E1S and E1 in VSMCs. Results from the present study seem to suggest that the expression levels of both STS and EST mRNA and activity may be significantly associated with the degree of atherosclerotic changes in the female aorta, which may be related to cytokines produced in situ, such as IL-1beta, in human atherosclerotic lesions.

Adult↗
PubMed2003

Adrenal adenomas: relationship between histologic lipid-rich cells and CT attenuation number.

OBJECTIVE: To evaluate the relationship between lipid-rich cells of the adrenal adenoma and precontrast computed tomographic (CT) attenuation numbers in three clinical groups. MATERIALS AND METHODS: Thirty-five surgically resected adrenal adenomas were used. The clinical diagnoses of the patients included 13 cases of primary aldosteronism, 15 cases of Cushing's syndrome, and 7 non-functioning tumors. The number of lipid-rich clear cells was counted using a microscopic eyepiece grid that contained 100 squares. The results were expressed as the percentages of lipid-rich areas. RESULTS: There was a strong inverse linear relationship between the percentage of lipid-rich cells and the precontrast CT attenuation number (R(2)=0.724, P<0.0001). There were significantly more lipid-rich cells in the primary aldosteronism and non-functioning tumor cases compared to cases of Cushing's syndrome (P=0.007 and 0.015, respectively). The CT attenuation numbers of the primary aldosteronism cases were significantly lower than those of Cushing's syndrome (P=0.0052). Furthermore, the CT attenuation numbers of the non-functioning tumor cases were lower than those of Cushing's syndrome cases. CONCLUSION: We showed that adrenal adenomas in primary aldosteronism and non-functioning tumors contain significantly more lipid-rich cells than those in Cushing's syndrome. They also showed significantly lower attenuation than that in Cushing's syndrome on CT scans. Our results suggest that precontrast CT attenuation numbers may be helpful in the differentiation of adenomas from non-adenomatous lesions, which include malignancies.

Adenoma↗