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Biomedical subjects

T Yao

Publications and source records attributed to T Yao.

At least 37 records · Page 2Linked to original sources
PubMed2003

Multiple microcarcinoids in a patient with long standing ulcerative colitis.

A male patient with a 17 year history of intractable ulcerative colitis of the entire type was treated by total proctocolectomy. Colonoscopy before surgery did not identify dysplasia. Histological examination of the resected colorectum revealed that, in addition to chronic inflammatory infiltrates, there were 21 areas of microcarcinoids located in the muscularis propria and in the superficial layer of the submucosa. Carcinoids may be more common than previously thought, and they may be a reactive phenomenon to a variety of factors in ulcerative colitis.

Adult↗
PubMed2003

Accuracy of radiographic assessment for the diagnosis of invasion depth in small invasive colorectal cancer.

Radiographic findings of 113 submucosally invasive colorectal cancers (CRCs) 10 mm. 47 CRCs had invaded the submucosa superficially while 66 CRCs had invaded deeply. The concordance rate in the assessment of radiology was 90.3% in smooth surface, 92.9% in central barium fleck, 90.3% in fold convergency and 79.6% in eccentric rigidity. Positive predictive value of central barium fleck for deep submucosal invasion was significantly higher in CRCs>10 mm than in those 10 mm. These findings suggest that barium radiography is a procedure which can give useful information in prediction of invasion depth in CRCs <or=10 mm in size.

Barium Sulfate↗
PubMed2002

Differences in p53 and cadherin-catenin complex expression between histological subtypes in diffusely infiltrating gastric carcinoma.

AIMS: The aim of this study was to elucidate possible clinicopathological differences between diffusely infiltrating gastric carcinoma of 'pure type' (poorly differentiated carcinoma without any glandular component) and 'mixed type' (coexistence of poorly differentiated carcinoma and intramucosal glandular component). METHODS AND RESULTS: The clinicopathological features and immunohistochemical expression of p53 and intercellular adhesion molecules (E-cadherin and alpha-, beta- and gamma-catenins) were compared between the patients with pure (n=59) and mixed (n=56) types of diffusely infiltrating gastric carcinoma. Intestinal metaplasia (P < 0.01), prominent lymphatic permeation (P < 0.001) and lymph node metastasis (P < 0.05) were more frequently observed in mixed type than in pure type, while survival probability did not differ between the two groups. The frequency of p53 over-expression was higher in mixed type (56%) than in pure-type (19%) (P < 0.001). In mixed type, p53 expression was not different between glandular and poorly differentiated components. By contrast, the expression of adhesion molecules was more frequently preserved in glandular components than in poorly differentiated components. CONCLUSIONS: These two subtypes seem to be different in nature and biological behaviour. The preservation of adhesion molecules in mixed type may be associated with higher incidence of lymphatic permeation and lymph node metastasis.

Adult↗
PubMed2002

Endosonographic features of Brunner's gland hamartomas which were subsequently resected endoscopically.

BACKGROUND AND STUDY AIMS: Brunner's gland hamartomas are uncommon duodenal submucosal tumors. We aim to describe their morphological characteristics, with particular attention to the endosonographic features. PATIENTS AND METHODS: We reviewed the radiological, endoscopic, endosonographic, and histological findings from six Brunner's gland hamartomas which were completely removed by endoscopic resection. RESULTS: The lesions appeared as broad-based, sessile, or pedunculated submucosal tumors, measuring 0.7 to 2 cm in maximal diameter. Three lesions contained tiny dimple-like depressions on the surface; in one lesion these were only recognized following the use of an endoscopic dye-spraying technique. All the lesions could be safely removed by endoscopic resection after endosonographic confirmation of the layer origin within the submucosa. The internal echo structure of the tumors appeared to be solid echogenic in two, simple cystic in two, and multicystic in the remaining two lesions. In three lesions with an indistinct boundary, some stromal proliferation and solid Brunner's glands were recognized in an area extending from the mucosa to the submucosa. These endosonographic features corresponded to histological findings comprising stromal proliferation and various degrees of solid and cystic glandular Brunner's glands. CONCLUSIONS: Brunner's gland hamartoma is characterized endosonographically by a heterogeneous solid and/or cystic mass within the submucosa.

Adult↗
PubMed2002

Serrated adenoma in familial adenomatous polyposis: relation to germline APC gene mutation.

BACKGROUND: Serrated adenoma is a precursor of colorectal cancer. AIM: To clarify possible genotype-phenotype correlations of serrated adenomas in familial adenomatous polyposis (FAP). PATIENTS: Eleven patients from eight families with FAP. METHODS: We performed total colonoscopy with multiple biopsies in patients. Neoplasia with a serrated glandular structure was regarded as a serrated adenoma. In each patient, germline mutations of the APC gene were determined. Colonic phenotype was compared with germline mutations of the APC gene. RESULTS: Serrated adenomas were found in three patients. These patients had macroscopic polyps <100 in number. Pedigrees with serrated adenomas had the truncating germline APC mutation at codon 161, 332, or 1556 while in the other pedigrees mutations were found between codons 554 and 1324. CONCLUSIONS: In FAP, serrated adenoma may be a phenotype characteristic of the attenuated form.

Adenoma↗
PubMed2001

Collapse of the Ia3d cubic symmetry by uniaxial stretching of a double-gyroid block copolymer.

We report an experimental observation of collapse of the Ia3d symmetry by stretching of an elastomeric block copolymer that forms a double-gyroid (DG) microdomain structure. Some new diffraction spots were observed for a deformed DG structure. These spots were assigned to [110] and [200] reflections. For the Ia3d symmetry, these reflections are prohibited by the extinction rule and therefore none of them appeared for the sample before deformation. Appearance of these reflections indicates breakdown of the extinction rule and can be explained as a result of collapse of the symmetry of glide when three-dimensional DG networks are partially ruptured upon stretching.

Journal Article↗
PubMed2001

A novel splice acceptor site mutation of protein S gene in affected individuals with type I protein S deficiency: allelic exclusion of the mutant gene.

Sequencing studies of the protein S gene (PROS1) in a Japanese patient suffering from recurrent thrombosis revealed the following. The proband and his first daughter, but not the second daughter, were having the type I protein S (PS) deficiency due to a novel point mutation from A to G at the intronic acceptor splice site in intron 13 of the PROS1. In the affected daughter, exclusion of the aberrant allele was assessed by the BstX1 dimorphism of PROS1 at Pro626 (CCG/CCA). The reduced PS activities in the proband and his first daughter were apparently due to defective production of mRNA from the mutant allele.

Alleles↗
PubMed2001

Changes in electronic structure by Li ion deintercalation in LiCoO2 from cobalt L-edge and oxygen K-edge XANES.

Cobalt L-edge and oxygen K-edge X-ray Absorption Near Edge Structure (XANES) investigated change in electronic structure by electrochemical lithium ion de-intercalation in LiCoO2. The Co L-edge XANES of Li(1-x)CoO2 did not show any chemical shift even at high x value. The oxygen K-edge XANES of Li(1-x)CoO2 indicated that the holes compensating the lithium ion deintercalation are located primarily in the oxygen 2p states rather than in the Co 3d states.

Journal Article↗
PubMed2001

EXAFS study of crystal structures of (Ba1-xLax)2In2O5+x and their oxide ion conductivity.

Crystal structures of(Ba1-xLax)2In2O5+x (x=0.00, 0.20, 0.30, 0.40, 0.50) were analyzed by EXAFS and the powder X-ray Rietveld method. A Fourier transform of In K-edge EXAFS data from (Ba1-xLax)2In2O5+x showed a peak between 1.2 and 2.0 A attributed to the nearest oxide ions around In3+ cation. The peak as back-Fourier transformed, and the structural parameters were refined by the least square fitting. The coordination number of In3+ cation increases with increasing La3+ cation) content. This means oxygen is introduced at interstitial site by keeping an electroneutrality. As a result of the oxygen distribution, the oxide ion vacancies distribute randomly. The electrical conductivities of (Ba1-xLax)2In2O5 rapidly increased above 1203 K due to the order-disorder transition of oxygen vacancy. On the other hand, the electrical conductivities of (Ba1-xLax)2In2O5+x (x=0.20, 0.30, 0.35. 0.40, 0.45, 0.50) did not show the sharp discontinuity in the conductivity because the disorder phase of defective perovskite type structure was stabilized by doping La3+ cations at A-site even at low temperature.

Journal Article↗
PubMed2001

Power Doppler sonography of hepatocellular carcinomas with portal-vein blood supply.

We report the power Doppler imaging (PDI) findings in 2 cases of hepatocellular carcinoma (HCC) with a portal-vein blood supply. Gray-scale sonography in both cases showed a well-circumscribed nodule, hypoechoic in case 1 and hyperechoic in case 2. PDI revealed an afferent tumor vessel with constant flow in both nodules, and CT during arterial portography demonstrated a portal-vein supply to both nodules. The nodules were diagnosed by percutaneous core biopsies as highly differentiated HCC. We also examined with PDI another 64 patients with 76 HCC nodules, and none of the nodules showed a constant-flow afferent tumor vessel. The presence of a constant-flow afferent tumor vessel indicates a supplying portal vein; but this is not diagnostic of HCC, and biopsy remains necessary to establish a final diagnosis.

Aged↗
PubMed2001

Multiple intracranial recurrent tumors with hyperprolactinemia combined with a parasellar malignant fibrous histiocytoma long after transfrontal surgery and irradiation to a pituitary adenoma.

We herein describe a 40-year-old woman with hyperprolactinemia, an empty sella and two extrasellar intracranial recurrent tumors which were revealed 23 years after the first transfrontal craniotomy and 18 years after the second transfrontal surgery and irradiation to a provable prolactin-producing pituitary macroadenoma. One recurrent tumor was in the right orbital apex causing right oculomotor nerve palsy, and the other tumor was in the right apex partispetrosae and foramen jugulare. Although her serum prolactin level decreased after the administration of bromocriptine mesilate, and the size of the two tumors remained unchanged, a malignant fibrous histiocytoma, which might have been induced by the irradiation 18 years before, grew rapidly in the right suprasellar-prepontine cistern to the right pedunculus cerebralis, leading to a poor prognosis. This case confirmed the importance of the life-lasting follow-up of pituitary adenomas treated with surgery and/or irradiation therapy. Not only ectopic recurrence of the primary tumor but also post-irradiation tumors may become apparent long after the removal of the primary tumor.

Adult↗
PubMed2001

Prevalence of Helicobacter pylori infection and correlation between severity of upper gastrointestinal lesions and H. pylori infection in Japanese patients with Crohn's disease.

BACKGROUND: The prevalence of Helicobacter pylori infection in Crohn's disease (CD) patients was investigated to determine whether the presence and severity of gastroduodenal lesions were related to H. pylori infection. METHODS: Infection rates were compared between CD group (n = 90) and the control group (n = 525). Correlations between endoscopically detected lesions and H. pylori positive rates were investigated. The relationship between drug therapy and the prevalence of H. pylori infection was also analyzed. RESULTS: H. pylori-positive rate of the 90 CD patients attending our clinic was 16.7%, significantly lower than the rate in healthy controls (40.2%) (P = 0.0001). The involvement of H. pylori infection in the gastroduodenal lesions of CD patients was also examined. The prevalence of gastroduodenal lesions in all CD patients was high, 92.2%. The lesions observed included ulcers, erosion, and "bamboo joint-like lesions" of the stomach, and ulcers, erosion, stenosis, and elevated lesions of the duodenum. None of these lesions were found to be related to H. pylori infection. However, H. pylori infection was found to exacerbate gastric ulcers (P = 0.036). The analysis of a possible relationship between a history of drug therapy and the low prevalence of H. pylori infection in CD patients showed that the prevalence of H. pylori infection was significantly lower in patients who had received antibiotics for 2 weeks or more (P = 0.002). CONCLUSIONS: The results suggest that H. pylori infection is essentially unrelated to the gastroduodenal lesions observed in CD. It seems likely, however, that H. pylori infection may exacerbate gastric ulcers and that H. pylori can be eradicated by prolonged use of antibiotics.

Adolescent↗
PubMed2001

Pharmacodynamic effects and kinetic disposition of rabeprazole in relation to CYP2C19 genotypes.

BACKGROUND: S-mephenytoin 4'-hydroxylase (CYP2C19) catalyses the metabolism of rabeprazole to some extent. Based on the metabolic and pharmacokinetic differences among other proton pump inhibitors such as omeprazole, lansoprazole and pantoprazole, rabeprazole appears to be the least affected proton pump inhibitor by the CYP2C19-related genetic polymorphism. AIM: To determine whether the pharmacodynamic effects of rabeprazole on intragastric pH and serum gastrin levels, and its pharmacokinetics depend on the CYP2C19 genotype status. METHODS: Eighteen healthy subjects, whose CYP2C19 genotype status was previously determined, participated in the study. They consisted of six each of homozygous extensive metabolisers (homo EMs), heterozygous extensive metabolisers (hetero EMs), and poor metabolisers (PMs). Helicobacter pylori status was determined by serology. After a single oral dose of 10 mg or 20 mg rabeprazole or water only (baseline data), intragastric pH values were monitored for 24 h. Plasma levels of rabeprazole and serum gastrin were also measured for 24 h post-dose. RESULTS: Five homo EM, six hetero EM and four PM subjects were H. pylori-negative. After rabeprazole administration, significant differences in intragastric mean pH values, serum gastrin AUC(0-24) and plasma levels of rabeprazole were observed among the three different genotype groups. CONCLUSION: The pharmacodynamic effects of rabeprazole and its pharmacokinetics depend on the CYP2C19 genotype status.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Efficacy of treatment with chimeric monoclonal antibody (Infliximab) to tumor necrosis factor-alpha for Crohn's disease in Japan: evaluation by rapid turnover proteins, and radiologic and endoscopic findings.

BACKGROUND: Several studies have reported that the chimeric monoclonal antibody to tumor necrosis factor (TNF)-alpha (Infliximab) is extremely valuable in the treatment of Crohn's disease. The aim of this study was to clarify the efficacy of this treatment in Japanese patients with Crohn's disease. METHODS: A 12-week multicenter, open trial of Infliximab was carried out and involved 25 patients with moderate to severe Crohn's disease who were resistant to conventional treatment. Patients received a single 2-h intravenous infusion of Infliximab at a dose of 1, 3, 5 or 10 mg/kg bodyweight. Clinical evaluation of this treatment response was defined as a reduction in the index of the inflammatory bowel disease (IOIBD) and of the Crohn's disease activity index scores (CDAI), and in serum levels of C-reactive protein (CRP) at 2, 4, 8 and 12 weeks, and as an increase in serum levels of rapid turnover proteins as well as improvement of radiologic and endoscopic findings at 4 weeks. RESULTS: The IOIBD score was reduced after 4 weeks in 66.7% of the group receiving 1 mg/kg Infliximab, 71.4% in the group receiving 3 mg/kg, 80.0% in the group receiving 5 mg/kg, and 85.7% in the group receiving 10 mg/kg. Improvement was better maintained over 12 weeks in the 5 and 10 mg/kg groups compared with the 1 and 3 mg/kg groups. Similar results were obtained for the CDAI scores. Serum levels of rapid turnover proteins significantly increased to within the normal ranges after infusion in all groups. Seven of the 11 (63.6%) patients evaluated showed improvement of radiologic and endoscopic findings. CONCLUSIONS: A single infusion of Infliximab was effective for the treatment of Japanese patients with Crohn's disease. Serum rapid turnover proteins reflected the clinical response to antibody for TNF-alpha well.

Adult↗
PubMed2001

Observer variation of diagnoses based on simple biopsy criteria differentiating among Crohn's disease, ulcerative colitis, and other forms of colitis.

BACKGROUND AND AIM: Simple mucosal biopsy criteria proposed by authors reliably differentiate idiopathic inflammatory bowel disease (IBD) from other forms of colitis (non-IBD) and Crohn's disease involving the colon (CD) from ulcerative colitis (UC). The aim of this study is to investigate the reproducibility of these criteria. METHODS: Three established pathologists and two medical students blindly examined 20 sets of multiple biopsy slides from patients with CD, 20 from those with UC, and 20 from those with non-IBD. The students had been given instructions on histological definitions using another 15 sets previously. Each observer evaluated 10 histological items required in the criteria and determined categorical diagnoses such as definite IBD and probable UC. Interobserver agreement for the individual histological items was measured by using kappa analysis and Pearson's correlation, while it was measured for categorical diagnoses with the use of Spearman's rank correlation. RESULTS: All of the individual histological items expressed excellent or fair-to-good agreement among the five observers, although two items associated with the criteria for CD and UC had poor agreements among the students. With regard to categorical diagnoses based on the criteria for IBD and non-IBD, and those for CD and UC, coefficients for Spearman's rank correlation exceeded 0.92 and 0.86 among the pathologists, and 0.76 and 0.74 among the students, respectively; all of the coefficients were statistically significant (P < 0.05). CONCLUSIONS: The simple criteria were sufficiently reproducible and would help most pathologists to make an automated and objective diagnosis.

Biopsy↗
PubMed2001

Electroporation in a model of cardiac defibrillation.

INTRODUCTION: It is known that high-strength shock disrupts the lipid matrix of the myocardial cell membrane and forms reversible aqueous pores across the membrane. This process is known as "electroporation." However, it remains unclear whether electroporation contributes to the mechanism of ventricular defibrillation. The aim of this computer simulation study was to examine the possible role of electroporation in the success of defibrillation shock. METHODS AND RESULTS: Using a modified Luo-Rudy-1 model, we simulated two-dimensional myocardial tissue with a homogeneous bidomain nature and unequal anisotropy ratios. Spiral waves were induced by the S1-S2 method. Next, monophasic defibrillation shocks were delivered externally via two line electrodes. For nonelectroporating tissue, termination of ongoing fibrillation succeeded; however, new spiral waves were initiated, even with high-strength shock (24 V/cm). For electroporating tissue, high-strength shock (24 V/cm) was sufficient to extinguish ongoing fibrillation and did not initiate any new spiral waves. Weak shock (16 to 20 V/cm) also extinguished ongoing fibrillation; however, in contrast to the high-strength shock, new spiral waves were initiated. Success in defibrillation depended on the occurrence of electroporation-mediated anodal-break excitation from the physical anode and the virtual anode. Some excitation wavefronts following electrical shock used a deexcited area with recovered excitability as a pass-through point; therefore, electroporation-mediated anodal-break excitation is necessary to block out the pass-through point, resulting in successful defibrillation. CONCLUSION: The electroporation-mediated anodal-break excitation mechanism may play an important role in electrical defibrillation.

Action Potentials↗
PubMed2001

Cap polyposis of the colon and rectum: an analysis of endoscopic findings.

BACKGROUND AND STUDY AIMS: Because of the rarity of cap polyposis of the colon and rectum, the endoscopic features of this condition have not been specified to date. The aim of this study is to characterize the endoscopic features of cap polyposis. PATIENTS AND METHODS: The diagnosis of cap polyposis was established by histologic findings in specimens obtained endoscopically or surgically from four patients. Colonoscopic findings in the four patients were retrospectively reviewed. RESULTS: The endoscopic features were divided into semipedunculated type (three patients) and flat-topped protruding type (one patient). In the semipedunculated type, the polyps were characterized by reddish protrusions of various configurations with eroded surface in the rectosigmoid colon. In the remaining patient, all the lesions were flat protrusions with a reddish central depression. The polyps of both types became smaller in size and fewer in number at the proximal part of the sigmoid colon. Multiple white specks were observed in the intervening mucosa in all four patients. CONCLUSIONS: The prominence of the polyps at the distal part of the colon and rectum and multiple white specks in the intervening mucosa seem to be the additional endoscopic features suggestive of cap polyposis.

Adult↗