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T Yao

Publications and source records attributed to T Yao.

At least 55 records · Page 3Linked to original sources
PubMed2001

Preoperative evaluation of submucosal invasive colorectal cancer using a 15-MHz ultrasound miniprobe.

BACKGROUND AND STUDY AIMS: Recently, it was reported that focal submucosal invasive colorectal cancer could be treated by polypectomy or endoscopic mucosal resection (EMR) because of the rarity of lymph-node metastasis. Our objective was to examine the accuracy and efficacy of a 15-MHz ultrasound miniprobe in the preoperative evaluation of the degree of submucosal invasion in colorectal cancer. PATIENTS AND METHODS: A total of 35 patients with submucosal invasive colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. The results of this imaging were compared with the histologic findings in resected specimens. RESULTS: Although the accuracy of the miniprobe in categorizing submucosal invasion into three subclasses (SM1, invasion limited to the upper third; SM2, limited to the middle third; SM3, limited to the lower third) was low (37.1%; 13/35), the accuracy in differentiation between < or = SMI (M and SMI) and > or = SM2 (SM2, SM3, MP, and S) was 85.7 % (30/35). CONCLUSIONS: The miniprobe can be useful for therapeutic decision-making in submucosal invasive colorectal cancer.

Adult↗
PubMed2001

Phenotypic expression of colorectal adenocarcinomas with reference to tumor development and biological behavior.

The purpose of this study is to clarify the correlation between cell differentiation and tumor development, including tumor aggressiveness and biological behavior. Eighty-three cases of advanced colorectal adenocarcinoma were randomly selected. Using immunohistochemical staining with antibodies to CD10, MUC2 and human gastric mucin (HGM), the colorectal adenocarcinomas could be classified into five types (18 small intestinal, 27 large intestinal, 2 gastric, 9 mixed and 27 unclassified). Each type had characteristic features. The small-intestinal type showed a relatively lower incidence of lymphatic permeation and higher venous invasion. The large-intestinal type showed a low incidence of venous invasion and lymph node metastasis. The mixed type revealed female and right-side-dominant distribution, large tumor size, high incidence of mucinous carcinoma, and low incidence of venous invasion. Gastric type was seen in only two cases (2%), which exhibited high histologic grade, lymphatic permeation and lymph node metastasis with no venous invasion. Such phenotypic classifications are considered to be useful not only for evaluation of the biological behavior of the carcinoma, but also for analysis of tumorigenesis.

Adenocarcinoma↗
PubMed2001

Clinical and endoscopic features of nonsteroidal anti-inflammatory drug-induced colonic ulcerations.

OBJECTIVE: Clinical and endoscopic features of nonsteroidal anti-inflammatory drug (NSAID)-induced colonic ulcerations have not been fully investigated. METHODS: During a 3-yr period from April 1996 to March 1999, 6076 subjects underwent total colonoscopy at our institutions. Among them, the diagnosis of NSAID-induced colonic ulceration was made by their clinical and colonoscopic findings. All patients diagnosed as having this disease underwent upper endoscopy and follow-up colonoscopy. Clinical features, serial changes in colonoscopic findings, and upper GI lesions were analyzed. RESULTS: Among the subjects, 14 patients were diagnosed as having NSAID-induced ulcerations. Seven patients were complicated by renal failure. Three patients had gastric ulcers concurrently. Eleven patients had colonic lesions in the ileocecal region. In 13 of 14 patients, initial colonoscopy demonstrated sharply demarcated, semilunar or circumferential ulcers without stricture formation. After discontinuance of NSAIDs, improvement of the ulcers without stricture or inflammatory polyps could be confirmed 3-10 wk later. In one patient with diaphragm-like stricture, follow-up colonoscopy performed 2 yr later demonstrated resolution of circumferential ulcer. CONCLUSIONS: NSAID-induced colonic ulceration may occur more frequently than previously recognized. Frank ulcerations, rather than stricture formation, seem to be the typical colonoscopic signs of NSAID-induced colonic ulceration.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Predictive value of endoscopic ultrasonography for regression of gastric low grade and high grade MALT lymphomas after eradication of Helicobacter pylori.

BACKGROUND: While a close association between gastric mucosa associated lymphoid tissue (MALT) lymphoma and Helicobacter pylori infection has been established, there are still cases which do not respond to H pylori eradication. AIMS: To investigate the clinicopathological factors which may help predict the therapeutic efficacy of H pylori eradication in gastric MALT lymphoma. PATIENTS: Forty one patients with gastric MALT lymphoma, including low and high grade lesions. METHODS: After endosonographic staging was determined, H pylori was eradicated in all patients, and the subsequent gastric pathological course was then investigated. RESULTS: Complete regression of MALT lymphoma was observed in 29(71%) patients, partial regression in five (12%), and no regression in seven (17%). Twenty six (93%) of 28 MALT lymphomas restricted to the mucosa but only three (23%) of 13 lymphomas which invaded the deep portion of the submucosa or beyond completely regressed. Kaplan-Meier analysis for the probability of complete regression of MALT lymphoma revealed a significant difference between tumours restricted to the mucosa and those invading the submucosa deeply or beyond (p<0.05). Neither the presence of a high grade component, perigastric lymphadenopathy, nor clinical staging prior to eradication correlated with the probability of lymphoma regression. CONCLUSIONS: Assessment of deep submucosal invasion by endosonography is valuable for predicting the efficacy of H pylori eradication in gastric MALT lymphoma.

Adult↗
PubMed2001

Regulation of MAP kinase by calcium-sensing receptor in bovine parathyroid and CaR-transfected HEK293 cells.

Regulation of the extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway by the extracellular calcium (Ca2+o)-sensing receptor (CaR) was investigated in bovine parathyroid and CaR-transfected human embryonic kidney (HEKCaR) cells. Elevating Ca2+o or adding the selective CaR activator NPS R-467 elicited rapid, dose-dependent phosphorylation of ERK1/2. These phosphorylations were attenuated by pretreatment with pertussis toxin (PTX) or by treatment with the phosphotyrosine kinase (PTK) inhibitors genistein and herbimycin, the phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor U-73122, or the protein kinase C (PKC) inhibitor GF109203X and were enhanced by the PKC activator phorbol 12-myristate 13-acetate. Combined treatment with PTX and inhibitors of both PKC and PTK nearly abolished high Ca2+o-evoked ERK1/2 activation in HEKCaR cells, demonstrating CaR-mediated coupling via both Gq and G(i). High Ca2+o increased serine phosphorylation of the 85-kDa cytosolic phospholipase A2 (cPLA2) in both parathyroid and HEKCaR cells. The selective mitogen-activated protein kinase (MAPK) inhibitor PD98059 abolished high-Ca2+o)-induced ERK1/2 activation and reduced cPLA2 phosphorylation in both cell types, documenting MAPK's role in cPLA2 activation. Thus our data suggest that the CaR activates MAPK through PKC, presumably through Gq/11-mediated activation of PI-PLC, as well as through G(i)- and PTK-dependent pathway(s) in bovine parathyroid and HEKCaR cells and indicate the importance of MAPK in cPLA2 activation.

Animals↗
PubMed2001

Micro-flow in vivo analysis of L-glutamate with an on-line enzyme amplifier based on substrate recycling.

A micro-flow enzyme system with a microdialysis probe is proposed for the amperometric detection of trace amounts of neurotransmitter L-glutamate released from rat brain cells. The L-glutamate oxidase (EC 1.4.3.11)/glutamate dehydrogenase (EC 1.4.1.4) coimmobilized reactor was used to enhance the sensitivity of L-glutamate as an on-line amplifier based on substrate recycling. A poly(1,2-diaminobenzene) film-coated platinum electrode was also used to selectively detect only the hydrogen peroxide generated into a upstream enzyme reactor, without interference from oxidizable species, such as L-ascorbate, the adsorption of low molecular-weight proteins in a dialysate, and NADPH added to the carrier solution to initiate substrate recycling. By the present in vivo system, L-glutamate was selectively assayed with about a 600-fold increase in sensitivity compared with the unamplified responses. The detection limit was 0.08 mumol dm-3. This method was applied to an in vivo assay of L-glutamate in the extracellular space of rat brain; also, monitoring of the L-glutamate level changed after a continuous stimulation of KCl to demonstrate the reliability of the system.

Animals↗
PubMed2001

Aberrant intracellular localization of RCAS1 is associated with tumor progression of gastric cancer.

A novel tumor-associated antigen, RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is expressed at a high frequency in human uterine and ovarian cancer cells as well as in other mammalian cancer cells. We investigated a relationship between RCAS1 expression and clinicopathological features in gastric cancer. Immunohistochemically, RCAS1 was detected in 98.4% of gastric carcinomas. However, its expression was also observed in non-cancerous gastric epithelial cells including gastric adenomas (100%), gastric ulcers (66.7%) and normal gastric epithelia (100%). Striking difference was observed in the pattern of RCAS1 expression between benign and malignant cells. In cases of normal gastric mucosae, gastric ulcers and gastric adenomas, RCAS1 was localized only in the perinuclear region of the mucosal epithelial cells (PN pattern), while, in most of gastric cancers (83.9%), it was detected diffusely in the cytoplasm and cell membranes of the tumor cells (DC pattern). In semi-quantitative RT-PCR analysis, RCAS1 mRNA levels in gastric adenocarcinoma tissues were significantly higher than those in non-neoplastic tissues (p=0.038). The PN pattern of RCAS1 expression was more frequently observed in well differentiated adenocarcinoma (25%) than in moderately differentiated adenocarcinoma (0%) (p=0.01). In addition, it is noteworthy that DC pattern of RCAS1 expression was more frequently recognized in carcinomas which invaded beyond the submucosa (100%) compared to intramucosal carcinoma (67.7%) (p=0.0026). These findings suggest that altered intracellular distribution of RCAS1 is strictly associated with tumor progression of gastric cancer and is a useful marker for the diagnosis and prognosis in gastric cancer.

Adenocarcinoma↗
PubMed2001

[Elevation distribution of precipitation chemistry in middle/upper troposphere in summer, the northern slope of central Himalayas].

During 1997 summer, fresh snow samples were collected from four snowfall events from the elevation of 5800 to 7000 m in the Dasuopu Glacier region on the northern slope of Mt. Xixabangma (28 degrees 33'N, 85 degrees 44'E), in order to understand the elevation distribution of the middle/upper tropospheric components in the remote region. The correlation between SO4(2-), NO3-, Ca2+ and Mg2+ in precipitation differs with type of air mass, indicating the dominant sources of ions vary in short-term (e.g. several days) during summer low dust period. In general, with elevation increases, the concentrations of NO3-, Ca2+ and Mg2+ decreases, while SO4(2-) increases, which are influenced by the variation of dominant sources of ions.

Air Pollutants↗
PubMed2001

[A case of paraneoplastic cerebellar degeneration with resting tremor].

A 65-year-old woman was operated for gastric adenocarcinoma in 1989. Six years later, peritonitis carcinomatosa, swelling of periaortic lymphnodes and high serum CA-125 were discovered. She received chemotherapy with 5-FU and cisplatin resulting in reduction of ascites. In September, 1998, the swelling of left supraclavicular lymphnodes and the elevation of serum CA-125 reappeared. Pathological diagnosis of supraclavicular lymphnodes was adenocarcinoma. Serum CA-125 was normalized by chemotherapy using cisplatin, farumorubicin and endoxan. However, unsteadiness appeared since December 10, 1998 followed by dysarthria and involuntary movement of neck and upper limbs. These symptoms progressed subacutely. The physical examination on admission revealed swelling of left suraclavicular lymphnodes, nystagmus on lateral gaze, saccadic eye movement on smooth pursuit and severe cerebellar ataxia. In addition, resting tremor of 3-4 Hz was observed at right hand, left wrist and neck which tended to increase amplitude by calculation. Similar movements were seen in the left first toe, though the frequency was lower. Brain MRI revealed mild cerebellar atrophy. She was diagnosed as paraneoplastic cerebellar degeneration (PCD) by serum anti Yo antibody and clinical course. The study of HLA showed positive link to A4 without A24. The primary focus of adenocarcinoma in cervical lymphnodes was suggested to be ovary rather than stomach due to the pattern of immunostaining for cytokeratin, CEA and CA125, although no carcinoma was found in ovarium clinically. The feature of this case is a PCD with resting tremor of frequency of 3-4 Hz and negative link to HLA-A24 in Japanese.

Adenocarcinoma↗
PubMed2001

[Changes in expression of angiotensin subtype AT1A and AT2 receptors in rats during cardiac remodeling following myocardial infarction].

Immunohistochemical and electron microscopic techniques and image analysis were employed to investigate the regulation of cardiac AT1A and AT2 subtype receptors in rats during cardiac remodeling following myocardial infarction (MI). Positive immunostaining for AT1A and AT2 receptors was observed in myocytes and vessels with AT1A being more than AT2. Three days after MI, disappearance of myocardial cross striation and fibroblast hyperplasia were found with electron microscopy. AT1A receptor protein expression in myocardial noninfarcted portion notably increased compared with that in sham-operated control rats (P < 0.001). No apparent changes were observed in AT2 receptor (P > 0.05). Two weeks after MI, myocyte cross striation and collagen deposition were found. Meanwhile, AT1A receptor staining decreased compared with that of three days after MI (P < 0.01), but there was still more than that of the control (P < 0.05). AT2 receptor was significantly increased compared with that of the sham-operated control rats (P < 0.001). These results suggest that both AT1A and AT2 receptor protein expression was upregulated in noninfarcted myocardium after MI, and the regulation of AT1A and AT2 receptors after MI may be involved in post-infarction cardiac remodeling.

Animals↗
PubMed2001

Development of colonic neoplasms and expressions of p53 and p21 proteins in experimental colitis of mice induced by dextran sulfate sodium.

The mechanisms underlying the frequent development of colorectal carcinomas in patients with ulcerative colitis (UC) are still not understood. This study was conducted to investigate whether p53 and p21 protein expressions contribute to carcinogenesis in an experimental model with dextran sulfate sodium (DSS) treatment, and to establish if this colitis model is suitable for study of cancer development in UC. A total of 40 mice were subjected to four administration cycles of 4% DSS for 7 days followed by plain water for the subsequent 14 days. The 33-surviving mice were sacrificed to examine the malignant transformation of colonic mucosa morphologically and to determine p53 and p21 expressions immunohistochemically. After DSS treatment periods, there were marked irregularities in the mucosal layer, the thickness of the entire bowel wall and the shortness of the colon. Histologically, tumors were found in 13 out of 33 (39.4%) mice. These 13 cases included 9 with a solitary lesion and 4 with double tumors. There were occurrences of invasive carcinomas in 8 lesions, high-grade dysplasia in 3 lesions and low-grade-dysplasia in 6 lesions. One presented with a polypoid tumor, 5 mm in diameter, while 16 had small flat lesions. There were 13 tumors on the left-sided colon, as opposed to 4 on the right-sided colon. Histological differentiation of invading carcinomas revealed that 6 out of 8 lesions were comprised of well differentiated adenocarcinomas, while 2 were moderately differentiated adenocarcinomas. Overexpression of p53 protein was found in 4 out of 8 invasive carcinomas, 2 out of 3 high-grade dysplasia cases and 2 out of 6 low-grade dysplasia cases, whereas only 1 out of 8 with invasive carcinoma was positive for p21. This experimental colitis model suggests that p53 and p21 protein expressions may contribute to carcinogenesis in DSS-induced colitis in mice and appears suitable to study cancer development in UC.

Animals↗
PubMed2001

Effect of cathepsin B on thymocyte apoptosis in spontaneously hypertensive rats.

AIM: To further investigate the mechanism of the thymus dysfunction in spontaneously hypertensive rats. METHODS: The location of cathepsin B expression was determined by in situ hybridization. The expression of cathepsin B was analyzed by Northern blot, and thymocyte apoptosis was detected by TUNEL and flow cytometer, respectively. RESULTS: The expression of cathepsin B in thymus paralleled with thymocyte apoptosis both in vitro and in vivo. Cathepsin B transcripts were located in the plasma of thymocytes and were more over-expressed of 6- and 8-week-old SHR than those in the thymus of WKY. CONCLUSION: Thymocyte apoptosis in SHR is increased and this phenomenon is associated with the expression of cathepsin B.

Animals↗
PubMed2001

Nuclear factor-kappaB p65 (RelA) transcription factor is constitutively activated in human gastric carcinoma tissue.

PURPOSE: Activation of transcription factor nuclear factor-kappaB (NF-kappaB) has been shown to play a role in cell proliferation, apoptosis, cytokine production, and oncogenesis. The purpose of this study was to determine whether NF-kappaB is constitutively activated in human gastric carcinoma tissues and, if so, to determine any correlation between NF-kappaB activity and clinicopathological features of gastric carcinoma. EXPERIMENTAL DESIGN: NF-kappaB activation was determined by immunohistochemical analysis of formalin-fixed, paraffin-embedded specimens from 64 gastric carcinoma patients. We quantified nuclear staining of RelA as a marker of NF-kappaB activation. RESULTS: Nuclear translocation of RelA was significantly high in tumor cells in comparison to that in adjacent normal epithelial cells (22.5 +/- 2.4% versus 8.6 +/- 1.5%, P < 0.0001). There was a significant correlation between NF-kappaB activation (nuclear translocation of RelA) and expression of urokinase-type plasminogen activator, an invasion-related factor and target of NF-kappaB in tumor cells (rho = 0.393; P = 0.0013). NF-kappaB activation was correlated with tumor invasion-related clinicopathological features such as lymphatic invasion of tumor cells (P = 0.0126), depth of invasion (P = 0.0539), peritoneal metastases (P = 0.0538), and tumor size (P = 0.0164). CONCLUSIONS: Collectively, the data show that NF-kappaB is constitutively activated in human gastric carcinoma tissues and suggest that NF-kappaB activity is related to tumor progression due to its transcriptional regulation of invasion-related factors such as urokinase-type plasminogen activator.

Active Transport, Cell Nucleus↗
PubMed2001

[Angiotensin II in rostral ventrolateral medulla mediates amino acids release from spinally projecting nerve terminals in the spinal cord].

Microdialysis in the intermediolateral column (IML) was employed to examine amino acids release induced by angiotensin II (ANG II) applied into the rostral ventrolateral medulla (RVLM). Microinjection of ANG II (100 pmol, n = 11) into the RVLM significantly increased (P < 0.01) the release of aspartate (from 4.75 +/- 1.01 to 8.90 +/- 2.28 pmol/20 microliters) and glutamate (from 18.99 +/- 8.64 to 73.88 +/- 29.26 pmol/20 microliters) in the spinal cord. The increase of glutamate release was significantly attenuated (P < 0.05) by pretreatment with losartan (10 nmol, n = 8) at the same RVLM site. Immunofluorescence double labeling combined with confocal microscopic observation demonstrated that 62%-91% of the glutamatergic neurons in the RVLM were double-labeled with AT1 receptors, supporting the view that ANG II-induced glutamate release in the spinal cord may arise from the AT1 receptor-containing glutamatergic spinally projecting neurons in the RVLM.

Angiotensin II↗
PubMed2000

Cyclization of polyubiquitin by the E2-25K ubiquitin conjugating enzyme.

For most substrates of ubiquitin (Ub)-dependent degradation, recognition by the proteasome is mediated by a covalently attached signal assembled from multiple ubiquitins linked to each other via the C terminus of one Ub and the epsilon-amine of Lys(48) of another Ub. Among Ub-conjugating enzymes, E2-25K is unique in its ability to synthesize in vitro unanchored Lys(48)-linked poly-Ub chains from mono- or poly-Ub, E1, and ATP; thus, E2-25K has distinct binding sites for donor and acceptor (poly)Ub. During studies of chain assembly by E2-25K, we observed that Lys(48)-linked tri-Ub was efficiently converted to a new species that upon SDS-polyacrylamide gel electrophoresis migrated between linear di-Ub and tri-Ub. Analysis of this product by mass spectrometry and tryptic digestion showed that it was a cyclic form of tri-Ub. Cyclization of tri-Ub requires E1, E2-25K, ATP, and that the linear substrate has a free Gly(76) C terminus on the proximal end Ub and a Lys(48) side chain available on the distal end Ub. E2-25K similarly can catalyze the cyclization of longer poly-Ub chains, including tetra- and penta-Ub. Although cyclic tri-Ub resists hydrolysis by the PA700 or isopeptidase T deubiquitinating enzymes, it can be disassembled to Ub monomers by isopeptidase(s) in a red blood cell extract. Thus, if cyclic poly-Ub forms in vivo, it will not accumulate as a dead-end product.

Animals↗