Biomedical subjects

Chee-Yin Chai

Publications and source records attributed to Chee-Yin Chai.

At least 37 records · Page 2Linked to original sources

PubMed2006

Differential change in expression of pulmonary ET-1 and eNOS in rats after chronic left ventricular pressure overload.

Pressure overload in the left ventricle of the heart follows a chronic and progressive course, resulting in eventual left heart failure and pulmonary hypertension (PH). The purpose of this research was to determine whether a differential pulmonary gene change of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS) occurred in adult rats with left ventricular overload. Eight groups of eight rats each were used (four rats with banding and four rats with sham operations). The rats underwent ascending aortic banding for 1 day, 2 weeks, 4 weeks, and 12 weeks before sacrifice. Significant medial hypertrophy of the pulmonary arterioles developed in two groups (4 and 12 weeks). Increased pulmonary arterial pressures were noted in three groups (1 day, 4 weeks, and 12 weeks). The aortic banding led to significant increases in pulmonary preproET-1 messenger RNA (mRNA) at 1 day and 12 weeks, and in pulmonary eNOS mRNA at 1 day and 12 weeks. In addition, there was increased pulmonary eNOS content at 1 day and 12 weeks in the banded rats, and increased lung cGMP levels were observed at 1 day. Increased lung ET-1 levels were also noted at 1 day (banded, 310 +/- 12 ng/g protein; sham, 201 +/- 12 ng/g protein; P < 0.01), 4 weeks (banded, 232 +/- 12 ng/g protein; sham, 201 +/- 12 ng/g protein; P < 0.01) and 12 weeks (banded, 242 +/- 12 ng/g protein; sham, 202 +/- 12 ng/g protein; P < 0.01). This indicates that the upregulated expression of ET-1 developed at least 4 weeks before eNOS expression in the course of PH, and, thus, medication against ET-1 could play a crucial role in treating PH with cardiac dysfunction secondary to aortic banding.

Animals↗

PubMed2006

The effects of debanding on the lung expression of ET-1, eNOS, and cGMP in rats with left ventricular pressure overload.

Pulmonary hypertension (PH) usually develops secondary to left ventricular (LV) dysfunction; therefore, it is also called retrograde PH. To investigate our hypothesis that PH is at least partially reversible, as in some congenital heart diseases, in a rat model we investigated whether release of constriction could attenuate pulmonary vascular remodeling and change the expression of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS). We used rats with LV dysfunction produced by an ascending aortic banding. In this study, there were four groups enrolled: 4-weeks banded (AOB(1-28); n = 7), 7-weeks banded (AOB(1-49); n = 7), debanded groups (AOB(1-28)/DeB(29-49); n = 7), and rats receiving a sham operation (n = 7). Subsequently, there was significant attenuation of medial hypertrophy in pulmonary arterioles and reversal of PH in the AOB(1-28)/DeB(29-49) group (sham, 19 +/- 1.3 mm Hg; AOB(1-28), 31 +/- 2.7 mm Hg; AOB(1-49), 32 +/- 2.7 mm Hg; and AOB(1-28)/DeB(29-49), 20 +/- 1.3 mm Hg). PreproET-1 mRNA and eNOS mRNA were measured by competitive reverse transcriptase (RT) polymerase chain reaction (PCR), and eNOS was measured by Western blotting. Compared with the banded groups, debanding significantly decreased pulmonary preproET-1 mRNA, pulmonary ET-1 (sham, 210 +/- 12 pg/g protein; AOB(1-28), 242 +/- 12 pg/g protein; AOB(1-49), 370 +/- 49 pg/g protein; and AOB(1-28)/DeB(29-49), 206 +/- 1.9 pg/g protein), and plasma ET-1 levels (sham, 10.1 +/- 1.5 pg/ml; AOB(1-28), 13.4 +/- 2.0 pg/ml; AOB(1-49), 15.4 +/- 2.0 pg/ml; and AOB(1-28)/DeB(29-49), 10.3 +/- 0.9 pg/ml protein). Debanding could not, however, alter pulmonary eNOS, eNOS mRNA, or cGMP. These findings suggest that pulmonary vascular remodeling, increased pulmonary arterial pressure, and upregulation of ET-1 gene expression are all reversible. We infer that it is the upregulated gene expression of ET-1, not eNOS, that is closely related to the development of the PH secondary to 4 weeks of aortic banding.

Animals↗

PubMed2005

Different impact from betel quid, alcohol and cigarette: risk factors for pharyngeal and laryngeal cancer.

The risks of betel quid chewing with or without tobacco, alcohol drinking and cigarette smoking have been well explored in the oral cavity but not in the pharynx and larynx. We conducted a case-control study to investigate the association of these three risk factors to cancers of the pharynx and larynx in Taiwan. A total cases of 148 pharyngeal cancer, 128 laryngeal cancer and 255 hospital controls, all men, were recruited. Betel quid chewing was a significant independent risk factor (adjusted odds ratio [aOR] = 7.7; 95% confidence interval [CI] = 4.1-15.0) similar to that of alcohol drinking (aOR = 6.6; 95% CI = 3.5-13.0) for pharyngeal cancer, but not for laryngeal cancer (aOR = 1.3; 95% CI = 0.7-2.5) on which cigarette smoking (aOR = 7.1) exerts a stronger significant independent risk than alcohol drinking (aOR = 3.8). For pharyngeal cancers, chewers who consumed >20 quid/day, chewed with inflorescence in the quid or swallowed the betel quid juice were at higher risks; significant dose-response effects were found in daily quantity of drinking and chewing, and cumulative quantity of drinking. Synergistic effects from the 3 risk factors existed both on the pharynx (aOR = 96.9) and the larynx (aOR = 40.3), and attributed for 93.1% and 92.9% respectively. Our study is the first evidence to show that betel quid chewing without tobacco has different impact on the pharynx (digestive tract) and the larynx (airway), and supports the concept that exposure quantity and direct mucosal contact with the betel quid juice may contribute to carcinogenesis. Our results show an important insight into the impact of betel quid chewing on other sites of the digestive tract other than the oral cavity.

Adult↗

PubMed2005

The role of p-STAT3 (ser727) revealed by its association with Ki-67 in cervical intraepithelial neoplasia.

OBJECTIVES: Constitutive activation of signal transducer and activator of transcription 3 (STAT3) has been described in many types of cancers. However, the role of phospho-STAT3 (p-STAT3) at serine residue 727 is in large part undetermined. Our purposes of this study were to evaluate the expression patterns of p-STAT3 (ser727) in cervical intraepithelial neoplasia (CIN) and to explore its possible role in the progression of cervical cancer. METHODS: Paraffin-embedded sections from 56 patients including 20 CIN 1, 10 CIN 2, and 26 CIN 3 were collected in this study. Immunohistochemical analysis was performed, and the expression patterns of p-STAT3 (ser727) were categorized by semiquantitative method and further correlated with the CIN histopathologic grade using the chi(2) test with Bonferroni adjustment for multiple comparisons and with the proliferation marker Ki-67 expression using Fisher's Exact Test. RESULTS: The categorized high p-STAT3 (ser727) expression group in nuclei of dysplastic cells was significantly higher in CIN 3 (76.92%), in comparison with CIN 1/2 (13.33%, P < 0.001). Moreover, both the nuclear and cytoplasmic p-STAT3 (ser727) expressions were correlated with Ki-67 nuclear staining (P < 0.001 and < 0.001, respectively). CONCLUSIONS: Our result revealed that aberrant expression levels of p-STAT3 (ser727) were significantly correlated with CIN lesion grade and cell proliferation. Evaluation of p-STAT3 (ser727) expression may provide additional prognostic information for the clinical course of the disease and therefore to be developed as a prognostic indicator for cervical cancer.

Biomarkers, Tumor↗

PubMed2005

Cutaneous metastasis from gastric adenocarcinoma: a case report.

Cutaneous metastasis from gastric adenocarcinoma is an infrequent disease entity. When present, it typically signifies disseminated disease with a poor prognosis. We report a case of a 57-year-old male patient with gastric cancer who developed generalized erythematous nodules on the chest, abdomen, back, neck, and four extremities 2 months postoperatively. Results of a skin biopsy disclosed groups of metastatic adenocarcinoma cells in the dermis and subcutaneous tissue, forming clusters and strands in a desmoplastic stroma. Histopathologic examination demonstrated that the cutaneous metastasis was of stomach origin.

Adenocarcinoma↗

PubMed2005

Encapsulated columnar-cell carcinoma of the thyroid: a case report.

Columnar-cell carcinoma is a rare form of papillary thyroid carcinoma. It is a biologically aggressive variant, according to the World Health Organization classification, due to its rapid growth, high local recurrence rate, and frequent lung, brain, and bone metastases. However, recent reports indicate encapsulated tumors confined to the thyroid gland are associated with a more favorable prognosis. We report a case of encapsulated columnar-cell carcinoma occurring in the right lobe of the thyroid in a 25-year-old female and discuss the histopathologic features, differential diagnosis, and prognostic factors.

Adult↗

PubMed2005

Abdominopelvic perivascular epithelioid cell tumor with overt malignancy: a case report.

Perivascular epithelioid cell tumor (PEComa) is a group of rare tumors composed of epithelioid cells with characteristic perivascular distribution and co-expression of the melanogenic marker HMB-45 and muscular markers. There are no documented parameters referring to the biologic behavior of PEComa. We report an abdominopelvic PEComa with overt malignancy in a 16-year-old girl. Histologically, the tumor showed the typical morphophenotypic characteristics of PEComa. Though the cytologic appearance of the tumor cells was relatively bland, the extensive necrosis, presence of lymph node metastases, and surrounding tissue invasion were all indicative of malignancy. Relapse of the tumor with multiple lymphadenopathy shortly after debulking surgery for the primary lesion, and postoperative adjuvant chemotherapy, further denoted its aggressive behavior.

Abdominal Neoplasms↗

PubMed2005

Fibroepithelial polyps causing ureteropelvic junction obstruction in a child.

Fibroepithelial polyps of the ureter are benign tumors arising from mesodermal tissue in the ureter wall. They are extremely rare lesions that can cause ureteropelvic junction obstruction in children. In this report, we describe an 11-year-old boy with fibroepithelial polyps of the ureter that caused left ureteropelvic junction obstruction. He presented with a 6-month history of left abdominal and flank pain. He also had short stature. Intravenous pyelography showed hydronephrosis without filling defects at the left ureteropelvic junction. Exploration revealed several finger-like polyps obstructing the lumen. This area was resected segmentally and a dismembered pyeloplasty was performed. No complications occurred during the postoperative period. The boy caught up in growth after the operation. Fibroepithelial polyps were confirmed by histology.

Child↗

PubMed2005

Compurerized morphometric study of thyroid follicular carcinoma in correlation with known prognostic factors.

This study investigates the correlation between computer-assisted nuclear morphometry and known prognostic factors in thyroid follicular carcinoma. Thirty-six patients with thyroid follicular carcinoma who underwent surgery between 1991 and 2001 were grouped according to sex, age, size of the primary lesion, the presence of vascular invasion, and metastases. Four nuclear parameters were measured and analyzed: mean nuclear area, mean nuclear perimeter, largest to smallest diameter ratio of the nuclei, and coefficient of variation of the nuclear area. Our results indicated that none of the chosen nuclear variables were significantly correlated with the prognostic factors studied. In conclusion, nuclear morphometry does not seem to correlate with known prognostic factors and cannot serve as an additional predicting factor for biologic behavior.

Adenocarcinoma, Follicular↗

PubMed2005

Unusual solitary fibrous tumors in the central nervous system: a report of two cases.

Solitary fibrous tumors (SFTs) are uncommon, and most are found in the pleura. Extrapleural SFTs are rare and have been found in the lung, pericardium, mediastinum, soft tissue of any site, and upper respiratory tract. SFTs of the central nervous system (CNS) are very rare. The biologic features are unknown and remain poorly understood from a clinical standpoint. Most neurosurgeons do not believe that SFTs can present as primary CNS neoplasms. Most SFTs are clinically benign and indolent, and recurrences after surgical excision are scarce. Because malignant transformation or metastasis has been reported, all SFTs should be treated as having malignant potential. Long-term follow-up is recommended. We report two cases, so that surgeons may recognize that this is an entity different from other spindle-cell CNS tumors.

Adult↗

PubMed2005

Hypoxia-inducible factor-1alpha is associated with risk of aggressive behavior and tumor angiogenesis in gastrointestinal stromal tumor.

BACKGROUND: The objective of this study was to evaluate the relationship of HIF-1alpha expression and tumor angiogenesis, recurrence/distant metastasis, and its value in the prediction of aggressive behavior of gastrointestinal stromal tumor (GIST). METHODS: Paraffin-embedded specimens from 62 patients with GIST were divided into two groups, low risk (n = 31) and high risk (n = 31) according to the tumor size, mitotic count and proliferating cell nuclear antigen (PCNA) index. We investigated the expression of the HIF-1alpha and analyzed correlation with tumor angiogenesis monitored by expression of vascular endothelial growth factor (VEGF) and tumor microvessel density using immunohistochemical staining. The data were analyzed with chi(2) test or Fisher's exact test and multivariate test. RESULTS: There were statistically significant differences between high risk (29/31; 93.5%) and low risk (8/31; 25.8%) of GIST in high expression of HIF-1alpha (P<0.0001). In addition, the incidence of recurrence/distant metastasis was significantly higher in cases of high HIF-1alpha expression (12/35; 34.3%) than in cases of low HIF-1alpha expression (1/24; 4.2%)(P = 0.009). Moreover, high VEGF expression (37/43; 86.0%) and microvessel density (30/32; 93.8%) were significantly higher in high HIF-1alpha expression tumors than in low-expression tumors (P < 0.0001). CONCLUSIONS: Our findings suggest that HIF-1alpha may play an important role in aggressive behavior and tumor angiogenesis in GIST. In addition, high expression of HIF-1alpha was significantly correlated with tumor recurrence/distant metastasis, so it may provide an ancillary prognostic factor for GIST.

Female↗

PubMed2005

Subungual verrucous carcinoma of the thumb treated by intra-arterial infusion with methotrexate.

BACKGROUND: For preservation of integrity of appearance and function in a 66-year-old male with an extremely rare case of verrucous carcinoma developing from the subungium of his right thumb, intra-arterial infusion with methotrexate was used. OBJECTIVE: To evaluate the effectiveness of arterial infusion with methotrexate in this unusual nail bed cancer. METHODS: Right brachial arterial catheterization and infusion with methotrexate (50 mg) were used every 24 hours together with simultaneous intramuscular injection of 6 mg of leucovorin every 6 hours for 10 days. RESULTS: At 4 years, 8 months after therapy, the patient was in sustained complete remission with a functionally normal right thumb. CONCLUSION: This case study suggests that intra-arterial infusion chemotherapy is a simple and effective method for thumb subungual verrucous carcinoma with the unique advantage of preservation of morphology and functional conditions. It can be considered an effective treatment option.

Aged↗

PubMed2005

Computerized nuclear morphometry in thyroid follicular neoplasms.

Differential diagnosis of follicular adenoma (FA) and follicular carcinoma (FC) of the thyroid can be challenging in the routine practice of surgical pathology because the diagnosis of FC is strictly defined and identification depends on the presence of invasion of the capsule or blood vessels. These features may be equivocally presented in the histological sections and interpreted subjectively by different pathologists, so an objective approach to solve this problem is essential. Computerized morphometry is a scientific tool to evaluate cellular changes and it can enhance the interpretation of morphological features by the transformation of pathological changes in cells to a qualitative form. The present study investigated the diagnostic role of objective computerized nuclear morphometry in follicular neoplasms. Thirty-six cases of thyroid FC and 36 cases of FA from patients who were matched by age and sex were studied. Four nuclear parameters were selected and analyzed: mean nuclear area, mean nuclear perimeter, largest to smallest diameter ratio of the nuclei, and coefficient of variation of the nuclear area. The results indicate that all the chosen nuclear variables were significantly correlated with the FA and FC studied. In conclusion, computerized nuclear morphometry can be considered a helpful ancillary tool for differential diagnosis of FA and FC.

Adenocarcinoma, Follicular↗

PubMed2005

The hepatoprotective effect of Bupleurum kaoi, an endemic plant to Taiwan, against dimethylnitrosamine-induced hepatic fibrosis in rats.

In the present study, three materials extracted or isolated from the roots of B. kaoi, an endemic plant to Taiwan, were used to be examined the hepatoprotective effect against dimethylnitrosamine (DMN)-induced hepatic fibrosis in rats, they were water extract (BKW), polysaccharide-enriched fractions (BKP) and saponin-enriched fractions (BKS). After treated with DMN for 4 weeks, the levels of aminotrasferases (GOT, GPT) were significantly elevated in serum, and the levels of total protein (TP) and albumin were significantly decreased in serum and liver homogenates. Furthermore, the collagen contents were significantly elevated in liver homogenates and corresponded to the hepatofibrotic pathological examination. As the results showed, treated with groups of BKW, BKP, BKS markedly reduced GOT, GPT levels in rats serum. In addition, treated with groups of BKW, BKP, BKS markedly raised TP levels in rats serum and liver homogenates. Furthermore, treated with groups of BKW, BKP markedly raised albumin levels in rats serum and liver homogenates. Treated with groups of BKW, BKP, BKS markedly raised interferon-gamma (IFN-gamma) levels in rats serum, where only BKS and silymarin markedly raised interkeukin-10 (IL-10) levels in rats serum compared to that of DMN treated rats. None of test materials of B. kaoi except silymarin reduced the malondialdehyde (MDA) levels, but BKW, BKP markedly raised hepatic glutathione (GSH) levels to reveal the activity of anti-lipid peroxidation. Otherwise, treated with groups of BKW, BKP, BKS significantly reduced collagen contents in rats liver homogenates. In conclusion, B. kaoi demonstrated the anti-inflammatory and anti-fibrotic activities followed by anti-oxidant activity of enhanced GSH production, enhanced the liver cell regeneration and concerned with regulations of INF-gamma and IL-10. The ability of hepatoprotective and anti-fibrotic activities of B. kaoi are higher than B. chinense, a Bupleuri Radix imported from China to Taiwan.

Animals↗

PubMed2005

Expression of human telomerase reverse transcriptase in thyroid follicular neoplasms: an immunohistochemical study.

Differential diagnosis of follicular adenoma (FA) and follicular carcinoma (FC) of the thyroid can be difficult in the routine practice of surgical pathology because the diagnosis of FC is strictly defined and determined by the presence of capsular and/or vascular invasion by the tumor. These features may be equivocal in the histologic sections. On the other hand, telomerase is expressed in many human cancers and is thought to contribute to their immortality. Human telomerase reverse transcriptase (hTERT) is the major determinant of human telomerase activity, and its expression is suggestive of capacity for unlimited replication. This case-control study examined the expression of hTERT using immunohistochemistry in 36 thyroid FC and 36 FA from patients who were matched by age and sex. The aim was to investigate the value of immunohistochemical staining for hTERT in the differential diagnosis of follicular neoplasms. The results revealed 23 cases of FC and 14 cases of FA that showed high expression of hTERT, with moderate to strong immunoreactivity. The remaining cases showed weak or negative staining. The difference between FA and FC was statistically significant (p < 0.05). In conclusion, immunohistochemical staining for hTERT can be considered an ancillary marker for differential diagnosis of FA and FC.

Adenocarcinoma, Follicular↗

PubMed2004

Characterization of DNA vaccines encoding the domains of calreticulin for their ability to elicit tumor-specific immunity and antiangiogenesis.

Antigen-specific cancer immunotherapy and antiangiogenesis are feasible strategies for cancer therapy because they can potentially treat systemic tumors at multiple sites in the body while discriminating between neoplastic and non-neoplastic cells. We have previously developed a DNA vaccine encoding calreticulin (CRT) linked to human papillomavirus-16 E7 and have found that this vaccine generates strong E7-specific antitumor immunity and antiangiogenic effects in vaccinated mice. In this study, we characterized the domains of CRT to produce E7-specific antitumor immunity and antiangiogenic effects by generating DNA vaccines encoding each of the three domains of CRT (N, P, and C domains) linked to the HPV-16 E7 antigen. We found that C57BL/6 mice vaccinated intradermally with DNA encoding the N domain of CRT (NCRT), the P domain of CRT (PCRT), or the C domain of CRT (CCRT) linked with E7 exhibited significant increases in E7-specific CD8(+) T cell precursors and impressive antitumor effects against E7-expressing tumors compared to mice vaccinated with wild-type E7 DNA. In addition, the N domain of CRT also showed antiangiogenic properties that might have contributed to the antitumor effect of NCRT/E7. Thus, the N domain of CRT can be linked to a tumor antigen in a DNA vaccine to generate both antigen-specific immunity and antiangiogenic effects for cancer therapy.

Angiogenesis Inhibitors↗

PubMed2004

Gastric cancer cell detection in peritoneal lavage: RT-PCR for carcinoembryonic antigen transcripts versus the combined cytology with peritoneal carcinoembryonic antigen levels.

Free cancer cells exfoliated from the serosal surfaces of primary cancers are considered to be responsible for peritoneal dissemination, which are both the most frequent pattern of treatment failure and the most important cause of death in gastric cancer patients. Detection of free cancer cells in the peritoneal cavity at the time of surgery, therefore, is thought to be of great value in predicting peritoneal recurrence and accordingly the prognosis of gastric cancer patients. This study was designed to determine whether free cancer cells in peritoneal lavage fluid from gastric cancer patients could be identified by a reverse-transcriptase polymerase chain reaction (RT-PCR) method specific to carcinoembryonic antigen (CEA) mRNA. Simultaneously, the results from conventional cytological examination were evaluated and the levels of CEA in peritoneal lavage were determined. Of the 40 gastric cancer patients enrolling in this investigation, 11 (27.5%) were positive for CEA mRNA in their peritoneal lavage, whereas only 6 (15%) and 8 (20%) were shown to be positive by cytological examination and peritoneal CEA (pCEA) assay, respectively. Furthermore, RT-PCR positive for CEA mRNA was correlated with the depth of tumor invasion (P<0.001), lymph node metastases (P=0.004), the TNM stage (P<0.001) and peritoneal recurrence (P<0.001). The technique of RT-PCR was more sensitive than conventional cytological examination and pCEA levels in the detection of peritoneal free cancer cells as well as in the prediction of peritoneal recurrence. In addition, CEA RT-PCR had a high concordance rate (82.5%) with the combination of cytology with pCEA levels. These observations suggest that it is feasible to identify free cancer cells in peritoneal lavage by using a CEA mRNA-specific RT-PCR method, and this assay can be a promising diagnostic modality for evaluating the risk of peritoneal dissemination in gastric cancer patients following operations.

Carcinoembryonic Antigen↗

PubMed2004

Upregulation of endothelial nitric oxide synthase and endothelin-1 in pulmonary hypertension secondary to heart failure in aorta-banded rats.

This study assessed alterations in expression of pulmonary endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) in rats with pulmonary hypertension (PH) after the ascending aorta had been banded. Rats were studied 12 weeks after banding, which resulted in left heart failure with elevated pulmonary arterial pressure (banded: 31.3 +/- 5.9 (mean +/- SD) mmHg; sham: 20.0 +/- 4.7 mmHg, P<0.05). Competitive reverse transcription-polymerase chain reaction demonstrated significant increases in pulmonary expression of preproET-1 mRNA and eNOS mRNA. Western blot analysis indicated increased pulmonary eNOS protein. Radioimmunoassays indicated increased plasma ET-1 concentrations in the pulmonary artery (banded: 12.4 +/- 1.5 pg/ml; sham: 9.0 +/- 1.3 pg/ml, P<0.01) and increased ET-1 content in lungs (banded: 240 +/- 21 ng/g protein; sham: 203 +/- 20 ng/g protein, P<0.05). There was increased immunohistochemical staining of eNOS and ET-1 in the pulmonary vascular endothelium of aorta-banded rats. Even in the presence of increased eNOS expression, it was not clear how nitric oxide (NO) production (decreased, unchanged, or increased) was involved in the compensatory mechanism to offset pulmonary vasoconstriction. Increased ET-1 expression may be important in mediating PH secondary to aortic banding, and may offer insights into the use of ET-1 antagonists in treating patients with PH secondary to heart failure.

Animals↗