Biomedical subjects

Yao-Chi Liu

Publications and source records attributed to Yao-Chi Liu.

29 records · Page 2Linked to original sources

PubMed2004

Modulation of human telomerase reverse transcriptase in hepatocellular carcinoma.

AIM: Most cancer cells acquire immortal capability by telomerase activation. The human telomerase reverse transcriptase gene (hTERT) is considered to be the major determinant of the enzymatic activity of human telomerase, and the hTERT promoter contains several c-Myc binding sites that mediate hTERT transcriptional activation. Few studies have examined the role of hTERT in hepatocarcinogenesis, and the relationship between c-Myc and telomerase in human hepatocellular carcinoma tissue is unknown. METHODS: We measured hTERT mRNA levels and c-Myc oncoprotein expression in 57 patients with hepatocellular carcinoma using in situ hybridization and immunohistochemistry, respectively. The transcription regulation of hTERT was evaluated by transient transfection of pGL3-1375 into the human hepatocellular carcinoma cell line J5. To determine the relationship between c-Myc and the hTERT promoter, a 1375-bp DNA fragment encompassing the promoter was placed upstream of the luciferase reporter gene and transiently transfected into the cell line. Two additional hTERT promoter constructs (-776 and -100 bp region) and an hTERT promoter-LUC construct containing 2 c-Myc mutations (pGL3-181 MycMT) were also used for luciferase assays. RESULTS: In 30 of 57 cases (52%), hTERT mRNA expression was associated with c-Myc protein expression. However, 16 of 57 cases (28%) showed strong hTERT mRNA detection without c-Myc protein expression, and 11 cases (19%) showed weak hTERT mRNA expression and strong c-Myc expression. Although luciferase activity was decreased between upstream 1 375 bp and 776 bp, there was no significant difference between upstream 776 bp and 100 bp. Finally, there was no significant decrease in activity after transfection of the hTERT promoter-LUC construct. CONCLUSION: The results indicate that c-Myc does not play a major role in gene regulation of the catalytic subunit of telomerase (hTERT) in human hepatocellular carcinoma. Other regulatory elements or epigenetic phenomena should be further investigated to understand hTERT gene regulation in human hepatocellular carcinoma.

Carcinoma, Hepatocellular↗

PubMed2004

Gallbladder contractility and volume characteristics in gallstone dyspepsia.

AIM: It is difficult to differentiate gallstone dyspepsia and functional dyspepsia by clinical symptoms and signs. We hypothesized that gallstone dyspepsia was related to abnormal gallbladder motility. We aimed to differentiate gallstone dyspepsia from functional dyspepsia by measuring gallbladder motility. METHODS: We measured gallbladder volume changes in response to gastric distension (saline 500 mL) and fatty meal in 10 normal volunteers (controls) and 62 patients with gallstones and dyspepsia before cholecystectomy. Forty cholecystectomized patients were symptom free or had improvement (group I), while the remaining 22 patients had persistent dyspepsia (group II). Gallbladder volume change and ejection fraction were analyzed and compared among the three groups. RESULTS: In group I, there were significant decreases in gallbladder volumes 5-25 min after gastric distension, compared to fasting volumes. Compared to normal volunteers and group II, group I had significantly decreased gallbladder volumes 10-20 min after drinking 500 mL of normal saline and 10 to 50 min after eating fatty meal. CONCLUSION: Our results support the hypothesis that increased gallbladder contraction after gastric distension or fatty meal may be related to dyspeptic symptoms in uncomplicated gallstone disease. These findings may be useful in differentiating functional dyspepsia from gallstone dyspepsia, patients with the latter disease may benefit from laparoscopic cholecystectomy.

Adult↗

PubMed2004

Comparison of transcatheter arterial chemoembolization, laparoscopic radiofrequency ablation, and conservative treatment for decompensated cirrhotic patients with hepatocellular carcinoma.

AIM: To compare the therapeutic effect of transcatheter arterial chemoembolization (TACE), laparoscopic radiofrequency ablation (LRFA), and conservative treatment for the therapy of decompensated liver cirrhosis patients with hepatocellular carcinomas (HCC). METHODS: Between October 2000 and July 2003, one hundred patients with histologically proven primary HCC and clinical decompensated liver cirrhosis (Child classification B or C) were included in this study. Forty patients received LRFA (LRFA group), twenty received TACE (TACE group), and forty received conservative treatment (control group). We compared the survival, recurrence, and complication rates in these three groups, making adjustment using the tumor metastatic node staging system. RESULTS: The major complication rate in the TACE group (9/20) was significantly higher than that in the LRFA group (7/40). For patients with TMN stage II HCC, the survival rate of the LRFA group was better than that of the TACE and control groups (P=0.003) but the recurrence rates between the LRFA and TACE groups did not differ. CONCLUSION: The LRFA group of patients had better clinical outcomes in terms of survival and complication rates in comparison with the TACE group or conservative treatment in patients with decompensated liver cirrhosis, especially in TMN patients with stage II HCC. LRFA is thus an appropriate alternative treatment for poor liver function among patients with HCC.

Aged↗

PubMed2004

Identification of tumor-associated plasma biomarkers using proteomic techniques: from mouse to human.

In an effort to identify tumor-associated proteins from plasma of tumor-bearing mice that may be used as diagnostic biomarkers, we developed a strategy that combines a tumor xenotransplantation model in nude mice with comparative proteomic technology. Five human cancer cell lines (SC-M1, HONE-1, CC-M1, OECM1, GBM 8401) derived from stomach, nasopharyngeal, colon, oral and brain cancers were subcutaneously inoculated into nude mice and compared to control nude mice injected with phosphate-buffered saline. One month later, plasma from mice inoculated with cancer cells was collected for proteomic analysis using two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). Comparison of plasma 2-DE maps from tumor-bearing mice with those produced from control mice revealed the overexpression of several mouse acute phase proteins (APPs) such as haptoglobin. Another APP, serum amyloid A (SAA), was found only in mice bearing tumors induced by the stomach cancer cell line SC-M1, which has not previously been demonstrated in xenotransplatation experiment. Furthermore, by using immunohistochemistry, SAA and haptoglobin were found to originate from the mouse hosts and not from the human cancer cell line donors. The protein alterations were further confirmed on patients with stomach cancers where up-regulated levels of SAA were also observed. These results indicate that APPs may be used as nonspecific tumor-associated serum markers. SAA in particular may serve as a potential marker for detecting stomach cancer. Taken together, the combination of the xenotransplatation model in nude mice and proteomics analysis provided a valuable impact for clinical applications in cancer diagnostics. In addition, our findings demonstrate that a panel of APPs might serve as screening biomarkers for early cancer detection.

Amino Acid Sequence↗

PubMed2004

Primary malignant mesothelioma of the greater omentum: report of a case.

We report a rare case of primary malignant mesothelioma of the greater omentum. To our knowledge, only one other such case has been described in the English literature. The patient was a 61-year-old Taiwanese woman without any history of exposure to asbestos, who presented with lower back pain. Abdominal sonography and computed tomography showed a 12 x 9 x 9-cm(3) mass occupying the lower abdomen. Laparotomy revealed a tumor in the greater omentum, invading the posterior wall of the uterus, without diffuse mesenteric thickening or multiple small nodules in the peritoneum. We performed en bloc resection of the mass, which involved omentectomy, hysterectomy, and bilateral salpingo-oophorectomy. Microscopically, the tumor cells were arranged in a tubulopapillary pattern lined by a single layer of uniform, cuboidal cells. A pattern of sclerotic stroma with irregular glandular elements was also recognized. Immunohistochemically, the tumor cells showed strong positivity for calretinin. The final pathologic diagnosis was malignant mesothelioma. The patient did not receive chemotherapy or radiotherapy, and has remained in good health without any evidence of recurrence for almost 3 years since her operation.

Female↗

PubMed2004

Telomerase and c-myc expression in hepatocellular carcinomas.

BACKGROUND: Telomerase is activated in the majority of cancer tissues and immortalized cell lines. The hTERT (human telomerase reverse transcriptase-major component of telomerase) gene promoter has been cloned and contains many c-myc binding sites that mediate hTERT transcriptional activation. Thus far, the role of hTERT in tumorigenesis in hepatocellular carcinoma (HCC) has been little studied using RNA in situ hybridization. The relationship between c-myc and telomerase in human HCC tissue is undetermined. MATERIALS AND METHODS: The telomerase activity was assayed using TRAP in specimens from 23 HCC patients, hTERTmRNA was detected using in situ hybridization from 57 HCC patients. The immunohistochemistry for c-myc and DNA sequence for hTERT promoter, and tumour differentiation in relation to hTERT and c-myc expression were determined in 57 specimens. RESULT: hTERTmRNA was found in 47/57 (82.5%) HCC specimens using in situ hybridization. The hTERT expression paralleled telomerase activity, but hTERTmRNA regulation was not significantly associated with c-myc level ( P<0.954) The DNA sequence analysis of the hTERT promoter in specimens from 17 HCC revealed 15 cases of nucleotide transition (T-->C) over 5'-end of distal E-box and one case of nucleotide transversion (G-->C) over 5'-end of proximal E-box. Neither the hTERT expression (P< 0.890) nor c-myc level (P < 0.348) were related to HCC differentiation. CONCLUSIONS: The hTERT expression paralleled telomerase activity. The telomerase activity in HCC was not only regulated by c-myc. Another pathways might contribute to hTERT and telomerase activity regulation. The lack of telomerase activity in specimens from 17.4% of HCC cases might indicate an alternative pathway for maintaining telomere length. Furthermore, both the telomerase activity and c-myc had no significant role in HCC differentiation.

Carcinoma, Hepatocellular↗

PubMed2003

Prognostic significance of CD44v5 expression in human thymic epithelial neoplasms.

BACKGROUND: Cell surface glycoproteins of the CD44 family play roles in cell-cell and cell-matrix interactions. Their aberrant expression has been implicated in tumor invasion and metastasis of a variety of neoplasms, but not, to date, of thymic epithelial tumors. METHODS: To investigate the expression of CD44 molecules, immunohistochemical staining using monoclonal antibodies against human CD44 standard form (CD44 s) and two common splicing variant (CD44v) isoforms, CD44v5 and CD44v6, was performed on 64 resected thymomas and 20 normal thymuses. These tumors were categorized histologically according to the World Health Organization (WHO) histologic classification, and the pathologic staging was classified according to the definitions of Masaoka. RESULTS: The positive expression rates in these patients were as follows: CD44 s (normal thymuses, 10%; thymomas, 22%), CD44v5 (normal thymuses, 0%; thymomas, 67%), and CD44v6 (normal thymuses, 0%; thymomas, 26%). CD44 s and CD44v5 immunoreactivity showed a positive correlation with tumor stages (p = 0.034 and 0.027, respectively). The CD44v5 expression of neoplastic cells in tumor capsules has significant correlation with tumor stages (II, 5%; III, 70%; IVA, 100%; p < 0.001). On the basis of univariate survival analysis, the Masaoka staging system, WHO histologic classification, and CD44v5 expression showed a statistically significant positive relation to survival (p < 0.001, 0.002, 0.011, respectively). Using Cox's regression model, increasing CD44v5 expression, the Masaoka staging, and the WHO classification system were found to be significant independent prognostic factors. CONCLUSIONS: CD44v5 expression is independently positively correlated with the aggressiveness of thymic epithelial tumors. The expression of CD44v5 may be a potential trigger of tumor invasion in thymomas.

Adult↗

PubMed2002

Sentinel node biopsy in early breast cancer in Taiwan.

The purpose of this study is to report the results of sentinel node (SN) biopsy for assessment of early breast cancer in Taiwan and to compare our results with those in other Asian countries and worldwide. We used methylene blue dye to identify SN in patients with clinically non-palpable breast mass and palpable breast mass smaller than 3 cm. We also explored the role of imprint cytology and immunochemical studies to identify metastatic cancer cells in the lymph nodes. A total of 221 procedures on 218 patients were performed by a single surgeon. The SN was identified in 85.5% of the cases. The overall accuracy of identifying tumors in SN was 97.4%, with a sensitivity of 90.9%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 96.4%. The use of immunochemical techniques helped to identify micrometastasis in SN or non-SN. Our results on SN biopsy with the dye method were similar to those reported from Japan and elsewhere. We concluded that sentinel node biopsy, together with the use of immunochemical techniques to identify micrometastatic foci, has allowed surgeons to decide at the time of surgery whether to perform axillary node dissection.

Adult↗

PubMed2002

Using technetium 99m tetrofosmin parathyroid imaging to detect parathyroid adenoma and its relation to P-glycoprotein expression.

BACKGROUND: The purpose of this study was to retrospectively evaluate technetium 99m tetrofosmin (Tc-TF) uptake in parathyroid adenomas and compare the results with their expression of multidrug resistance-mediated 170-kDa P-glycoprotein (Pgp). METHODS: Twenty patients with larger parathyroid adenomas (> 1.5 g) and the other 40 patients with smaller parathyroid adenomas (0.5-1.5 g) underwent early and delayed (10-minute and 2-hour) Tc-TF parathyroid imaging before operation. In this retrospective study, immunohistochemical analyses were performed on multiple nonconsecutive sections of the 40 parathyroid adenomas and 40 normal control specimens (20 normal parathyroid glands and 20 normal thyroid specimens) to detect Pgp expression. RESULTS: The Tc-TF parathyroid image accurately localized 17 larger and 16 smaller parathyroid adenomas, but not the remaining 3 larger and 4 smaller adenomas. The 17 larger and 16 smaller parathyroid adenomas with significant Tc-TF uptake on the delayed 2-hour parathyroid images revealed negative Pgp expression, but the 3 larger and 4 smaller adenomas without significant Tc-TF uptake, as well as 20 normal parathyroid glands and 20 normal thyroid specimens, revealed positive Pgp expression. CONCLUSIONS: Not only the size of parathyroid adenomas, but Pgp expression also limited the sensitivity of Tc-TF parathyroid image to localize parathyroid adenomas before the operation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

Intussusception as the initial manifestation of AIDS associated with primary Kaposi's sarcoma: a case report.

Kaposi's sarcoma (KS) is the most common AIDS-associated neoplasm. It involves the gastrointestinal tract, skin and lymph nodes with about equal frequency. However, most cases of gastrointestinal KS are clinically silent and found incidentally. We report the case of a 31-year-old homosexual man who developed intussusception in association with a primary ileal KS. He was admitted due to abdominal pain lasting 2 hours. Flat abdominal roentgenogram revealed small bowel ileus in the central abdomen. Abdominal sonography and computerized tomography revealed an intraluminal soft tissue mass in the small intestine with an intussusception. Exploratory laparotomy found an ileal tumor mass 90 cm proximal to the ileocecal valve. Pathologic examination of the resected intestine showed KS. HIV-1 infection was confirmed by Western blot. The CD4 T-cell count was 59/mm3. In conclusion, intussusception by enteric KS may present as the initial AIDS-associated neoplasm in patients with HIV infection.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Comparison of FDG-PET and technetium-99m MIBI SPECT to detect metastatic cervical lymph nodes in well-differentiated thyroid carcinoma with elevated serum HTG but negative I-131 whole body scan.

The aim of this study was to evaluate the usefulness of 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) in detecting metastatic cervical lymph nodes (LN) in well-differentiated thyroid carcinoma (DTC) after total thyroidectomy and radioiodine-131 (I-131) treatments in patients with elevated serum human thyroglobulin (hTg) levels but negative I-131 whole body scan (WBS). Fifteen DTC patients underwent nearly total thyroidectomy and I-131 treatments with cervical LN metastases were included in this study. All subjects had negative I-131 WBS and elevated hTg levels (hTg > or = 10 microIU/ml) under thyroid-stimulating hormone (TSH) stimulation (TSH > or = 30 microIU/ml). FDG-PET could detect all of the 15 (100%) patients with metastatic cervical LN, but Tc-99m MIBI SPECT revealed lesions in only 9 out of 15 (60%) patients (p value < 0.05). This study demonstrated that FDG-PET is more sensitive than Tc-99m MIBI SPECT in detecting metastatic cervical LN in DTC with elevated serum hTg levels but negative I-131 WBS.

Adult↗