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Biomedical subjects

Wen-Chi Chen

Publications and source records attributed to Wen-Chi Chen.

At least 55 records · Page 3Linked to original sources
PubMed2003

Effects of Tamm-Horsfall protein on the protection of MCDK cells from oxalate induced free radical injury.

Renal cell injury and fixed particle formation is one of the theories of urinary stone formation. The exposure of renal epithelial cells to oxalate ions and calcium oxalate monohydrate crystals can cause free radical generation and increase lipid peroxidation. Tamm-Horsfall protein (THP) has a protective effect on the production of free radicals in vitro. We aimed to show that THP (and its deglycosylated products, D-THP) could protect culture cells from free radical injury in vivo as well as the possible mechanism by which this is done. Exposure of Madin-Darby canine kidney (MDCK) cells to Ox resulted in a significant increase in the release LDH, NBT and MDA, as well as an increase in caspase 3 activity, all of which were further elevated when COM crystals were added. With the addition of THP at 500 nM, there was a significant decrease in the release of LDH and the production of MDA and NBT. A decrease in capase 3 activity was observed when 500 nM THP was added to the culture medium that reached 32.7% and 40.4% of inhibition in CaOx+THP and CaOx+COM+THP, respectively. THP decreased the adhesion of COM crystals to the MDCK cells but lost its effect when THP was deglycosylated. The results indicate that both Ox and COM crystals cause the release of LDH, MDA, NBT and increase the activity of capase 3 in MDCK cells. As a free radical scavenger, THP reduces the amount of free radicals and provides significant protection at a critical concentration of 500 nM. The deglycosylated THP decreased the effect of the protection of the MDCK cells from oxalate-induced injury and an increase of adhesion of the COM crystals to the MDCK cells. Therefore, the effects of THP on the protection of oxalate induced radical injury may be partly due to its intact glycosylation and its adhesion to the cell membrane.

Adjuvants, Immunologic↗
PubMed2003

Interleukin-1beta and interleukin-1 receptor antagonist gene polymorphism in postmenopausal women: correlation to bone mineral density and susceptibility to osteoporosis.

OBJECTIVE: Osteoporosis is a common disorder with a strong genetic component. Our aim was to investigate the correlations of the interleukin-1beta (IL-1beta) and interleukin-1 receptor antagonist (IL-1Ra) gene polymorphisms with bone mineral density (BMD) and their relationship to osteoporosis. METHODS: The IL-1beta (promoter and exon 5) and IL-1Ra (intron 2) gene polymorphisms were determined using polymerase chain reaction. BMD of the lumbar spine and proximal femur were measured using dual-energy X-ray absorptiometry. RESULTS: The prevalence of each genotype of the interleukin-1 related genes in the study population was: (1) 14% C/C, 71.5% C/T, and 14.5% T/T in IL-1beta promoter; (2) 95.3% E1/E1 and 4.7% E1/E2 in IL-1beta exon 5; (3) 92.4% I/I, 6.4% I/II, and 1.2% II/II in IL-1Ra intron 2. After adjustment for potential confounding factors such as age, height, weight, years since menopause, and daily calcium intake, subjects with genotype E1/E2 (n=8) in IL-1beta exon 5 had lower BMD values and a significantly greater risk for osteoporosis (OR 10.6, 95% CI 1.3-83.8) at the lumbar spine when compared with subjects with genotype E1/E1 (n=164) in IL-1beta exon 5. CONCLUSION: The Taq I IL-1beta exon 5 gene polymorphism is associated with reduced BMD and predisposes women to osteoporosis at the lumbar spine, but our results should be interpreted with caution because of the small number of subjects with the unfavorable E1/E2 genotype.

Bone Density↗
PubMed2003

TAP1 gene AccI polymorphism is associated with atopic bronchial asthma.

Asthma is a hyperresponsive airway disease that may involve inflammation responses. A transporter associated with the antigen processing 1 gene (TAP1) is involved in antigen processing, and is therefore considered to play a role in the pathogenesis of bronchial asthma. The aim of this study was to test whether the polymorphisms of the TAP1 gene are a genetic marker for susceptibility to bronchial asthma. A normal control group comprised of 43 healthy people, and 116 patients with allergic asthma were examined in this study. The polymorphism was detected by polymerase chain reaction (PCR)-based restriction analysis. Associations between atopic bronchial asthma and TAP1 polymorphisms were evaluated. The results revealed no significant differences between normal individuals and asthmatics in regard to the TAP1 gene DpnII polymorphism (P=0.752). However, there was a significant difference between the control and asthma groups as regards the TAP1 gene AccI polymorphism (P=0.020). The odds ratio (OR) of GG homozygotes of the TAP1 AccI polymorphism was 229.8 compared with the AA homozygote group. The results show that the AccI polymorphism may be an indicator for atopic bronchial asthma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Interleukin-10 gene -627 allele variants, not interleukin-I beta gene and receptor antagonist gene polymorphisms, are associated with atopic bronchial asthma.

Asthma is an airway hyperresponsive disease characterized by the expression of multiple inflammatory genes, including cytokines. Interleukin-I and interleukin-10 (IL-1 and IL-10) are cytokines that might play a role in the process of inflammation and are therefore considered to be involved in the pathogenesis of bronchial asthma. The aim of this study was to test whether the polymorphisms of the promoter region and exon 5 of the IL-1 gene, intron 2 of the IL-1Ra gene, and -627 nucleotide (C/A) of the IL-10 gene could be genetic markers for the susceptibility of bronchial asthma. A normal control group made up of 47 healthy volunteers and 117 patients with bronchial asthma were examined in this study. We analyzed the variable number of tandem repeats at intron 2 of the IL-1Ra gene for the polymorphisms by polymerase chain reaction (PCR). PCR-based restriction analysis of the IL-1 gene polymorphisms of the promoter region and exon 5 was carried out by the endonucleases Ava I and Taq I, respectively. The IL-10 gene -627 C/A polymorphisms were investigated by PCR-based restriction analysis. The distribution of CC homozygotes in the IL-10 gene was significantly lower in asthma patients than in controls (P=0.013, OR=3.599, 95% CI=1.240 approximately 10.441). The polymorphisms studied in the IL-1 genes did not reveal any significant association with bronchial asthma when compared with the control group (promoter region by chi-square test, P=0.627; exon 5 region by Fisher's exact test, P=0.403). Only two alleles of the IL-1Ra gene corresponding to one and two copies of an 86-base pair sequence repeat were identified by PCR in the control group. There were three alleles found in the asthmatic patient group. The results revealed no significant differences between normal individuals and asthma patients (P=0.454, Fisher's exact test). The IL-10 gene -627 "A" allele is an associated risk factor of developing atopic asthma.

Adolescent↗
PubMed2003

Prediction of survival in surgical unresectable lung cancer by artificial neural networks including genetic polymorphisms and clinical parameters.

Lung cancer, a common malignancy in Taiwan, involves multiple factors, including genetics and environmental factors. The survival time is very short once cancer is diagnosed as being in advanced stage and surgically unresectable. Therefore, a good model of prediction of disease outcome is important for a treatment plan. We investigated the survival time in advanced lung cancer by using computer science from the genetic polymorphism of the p21 and p53 genes in conjunction with patients' general data. We studied 75 advanced and surgical unresectable lung cancer patients. The prediction of survival time was made by comparing real data obtained from follow-up periods with data generated by an artificial neural network (ANN). The most important input variable was the clinical staging of lung cancer patients. The second and third most important variables were pathological type and responsiveness to treatment, respectively. There were 25 neurons in the input layer, four neurons in the hidden layer-1, and one neuron in the output layer. The predicted accuracy was 86.2%. The average survival time was 12.44 +/- 7.95 months according to real data and 13.16 +/- 1.77 months based on the ANN results. ANN provides good prediction results when clinical parameters and genetic polymorphisms are considered in the model. It is possible to use computer science to integrate the genetic polymorphisms and clinical parameters in the prediction of disease outcome. Data mining provides a promising approach to the study of genetic markers for advanced lung cancer.

Adult↗
PubMed2003

Insulin-like growth factor-II gene polymorphism is associated with primary open angle glaucoma.

Hypoxia and ischemia play important roles in the onset and progression of glaucoma. Insulin-like growth factors (IGF) are important neurotrophic agents that respond to hypoxia-ischemia. In this study, we enrolled 60 primary open angle glaucoma (POAG) patients and 104 healthy volunteers from the China Medical College Hospital. Among the polymorphism of IGFs gene, exon 9 Apa I C/T gene polymorphism is the most frequently seen. The polymorphism was observed following polymerase chain reaction based restriction analysis used to to resolve the relationship between IGF-II exon 9 Apa I C/T gene polymorphism and POAG. The distribution of the IGF-II exon 9 gene polymorphism showed statistical differences in the distribution of genotype frequencies between POAG patients and normal controls (P=0.010). The odds ratio of C/C homozygote was 0.266 (95% confidence interval=0.636 approximately 0.111). IGF-II is an important neurotrophic agent and regulates the suffering of POAG. C/C homozygote of IGF-II exon 9 Apa I C/T gene polymorphism is a useful marker of POAG in Chinese.

Adult↗
PubMed2003

Vascular endothelial growth factor gene-460 C/T polymorphism is a biomarker for prostate cancer.

OBJECTIVES: To use the Bst U I polymorphism as a genetic marker in the search for the association between patients with prostate cancer and normal control subjects. The formation or progression of prostate cancer is presumed to be associated with a polymorphism of the vascular endothelial growth factor (VEGF) gene. The most frequently seen polymorphism is Bst U I (C to T) located at the -460th nucleotide upstream of the VEGF gene. METHODS: A normal control group of 119 healthy people and 96 patients with prostate cancer were examined. The polymorphism was seen after polymerase chain reaction-based restriction analysis. RESULTS: The analysis revealed significant differences between normal individuals and patients with cancer (P <0.001). Also, the distribution of the "TT" homozygote in the patient group was greater than that in the control group. The odds ratio per copy of the "T" allele was 2.3 (95% confidence interval 1.4 to 3.8) and was 2.2 (95% CI 1.3 to 3.8) when adjusted for age. No statistically significant differences in clinical stage or grade were found. We also categorized the 54 patients who received hormonal therapy into response and nonresponse groups, but no statistically significant differences between these two groups were revealed (P = 0.110, Fisher's exact test). CONCLUSIONS: The Bst U I polymorphism of the VEGF gene is a suitable genetic marker of prostate cancer but cannot be used in the prediction of the outcome of patients who have received hormonal therapy.

Aged↗
PubMed2003

Osteocalcin gene HindIII C/T polymorphism is a biomarker for prostate cancer and responsiveness to hormone therapy.

OBJECTIVES: Osteocalcin is a vitamin-K dependent protein which is related to the metabolism of bone and calcium. The formation or progression of prostate cancer is presumed to be associated with the osteocalcin gene. The most frequently seen polymorphism is HindIII which is located at the promoter region. HindIII is therefore a possible genetic marker in the search for the association between prostate cancer and normal control subjects. METHODS: In our study, a normal control group of 132 healthy people and 96 patients with prostate cancer were examined. The polymorphism was seen following polymerase chain reaction (PCR) based restriction analysis. RESULTS: The result revealed significant differences between normal individuals and cancer patients (p=0.034) and the distribution of the "CC" homozygote in the control group was higher than that in the patient group. No statistical differences were found in clinical staging and grading. The 54 patients who received hormone therapy were further categorized into response and non-response groups, statistical differences between these two groups were revealed (p=0.007, Fisher's exact test). CONCLUSIONS: Based on our results, we conclude that the HindIII polymorphism of the osteocalcin gene is a suitable genetic marker of prostate cancer which can be used in the prediction of the outcome of patients who receive hormone therapy.

Aged↗
PubMed2003

A prospective, randomized trial of endoscopic hemoclip placement and distilled water injection for treatment of high-risk bleeding ulcers.

BACKGROUND: Although endoscopic hemoclip therapy is widely used in the treatment of GI bleeding, there are few prospective trials that assess its efficacy. This study evaluated the efficacy and safety of hemoclip placement and distilled water injection for the treatment of high-risk bleeding ulcers. METHODS: Seventy-nine patients with major stigmata of ulcer hemorrhage were randomly assigned to either endoscopic hemoclip placement (n = 39) or injection with distilled water (n = 40). RESULTS: Initial hemostasis was achieved in all patients treated with hemoclips and 39 treated by distilled water injection (respectively, 100.0% vs. 97.5%; p = 1.00). Bleeding recurred in 4 and 11 of patients, respectively, in the hemoclip and water injection groups. It occurred significantly more frequently in the injection group (hemoclip, 10.3%; injection, 28.2%; p = 0.04). No major procedure-related complication occurred in either group. Emergency operations were performed in 5.1% of patients treated with hemoclips versus 12.5% of those in the water injection group (p = 0.43). Hospital days and mortality rate were similar in both groups. CONCLUSION: Endoscopic hemoclip placement is a safe and effective hemostatic method that is superior to distilled water injection for treatment of bleeding peptic ulcer.

Female↗
PubMed2003

Association of E-cadherin gene 3'-UTR C/T polymorphism with calcium oxalate stone disease.

INTRODUCTION: Urinary stone disease is one of the most commonly seen urological diseases in Taiwan. Single nucleotide polymorphisms (SNPs) are commonly used for the investigation of genetic markers for stone disease. E-cadherin (CDH-1) is one of the cellular junction proteins related to the integrity of epithelial cells. Our aim was to investigate a polymorphism of the CDH-1 gene 3'-UTR as a possible genetic marker in the search for the genetic causes. MATERIALS AND METHODS: 148 patients with calcium oxalate stone were compared with 103 healthy controls for the frequency of CDH-1 3'-UTR polymorphisms. The polymorphism was detected by polymerase chain reaction-based restriction analysis (PML I endonuclease). RESULTS AND CONCLUSIONS: The results revealed significant differences between normal individuals and calcium stone disease patients (p = 0.0013). The distribution of genotype TT homozygote was higher in stone patients (51.5%) than in the control group (43.4%). The odds ratio for T allele compared to C allele was 2.0. We have concluded that polymorphisms of CDH-1 3'-UTR is a valid genetic marker for calcium stone disease.

Adult↗
PubMed2003

The ALUI calcitonin receptor gene polymorphism (TT) is associated with low bone mineral density and susceptibility to osteoporosis in postmenopausal women.

Osteoporosis is a common disorder with a strong genetic component. Our aim was to evaluate the correlation of the ALUI calcitonin receptor gene polymorphism to bone mineral density and their relationship to osteoporosis. We determined the ALUI calcitonin receptor gene polymorphism using polymerase chain reaction-based restriction analysis in 167 postmenopausal women in Taiwan. The polymorphism was detected by the restriction enzyme ALUI, where the C allele indicated the absence of the cuttable site and the T allele indicated its presence. Bone mineral density of the lumbar spine and proximal femur were measured using dual-energy X-ray absorptiometry. The allelic frequencies for the 167 postmenopausal women in Taiwan were 86.5% for C and 13.5% for T in ALUI restriction fragment length polymorphisms. The prevalence of each genotype in the study population was 2.4% TT, 22.2% CT, and 75.4% CC. The three genotypic groups differed significantly in unadjusted and adjusted bone mineral density at the lumbar spine and the femoral neck. Unadjusted and adjusted bone mineral density values were lowest in women with the TT genotype. The ALUI calcitonin receptor genotype showed a positive association with prevalence of osteoporosis in the subjects. That is, women with genotype TT had a greater risk for developing osteoporosis at the lumbar spine and at the femoral neck. The ALUI calcitonin receptor gene polymorphism is associated with reduced bone mineral density and predisposes women to osteoporosis, but should be interpreted with caution because of the small number of subjects in the unfavorable TT genotype.

Absorptiometry, Photon↗
PubMed2003

Endoscopic banding ligation can effectively resect hyperplastic polyps of stomach.

AIM: Bleeding and perforation are the major and serious complications associated with endoscopic polypectomy. To develop a safe and effective method to resect hyperplastic polyps of the stomach, we employed rubber bands to strangulate hyperplastic polyps and to determine the possibility of inducing avascular necrosis in these lesions. METHODS: Forty-seven patients with 72 hyperplastic polyps were treated with endoscopic banding ligation (EBL). On 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcomes of the strangulated polyps. RESULTS: After being strangulated by the rubber bands, all of the polyps immediately became congested (100%), and then developed cyanotic changes (100%) approximately 4 minutes later. On follow-up endoscopy 2 weeks later, all the polyps except one had dropped off. The only one residual polyp shrank with a rubber band in its base, and it also dropped off spontaneously during subsequent follow-up. No complications occurred during or following the ligation procedures. CONCLUSION: Gastric polyps develop avascular necrosis following ligation by rubber bands. Employing suction equipment, EBL can easily capture sessile polyps. It is an easy, safe and effective method to eradicate hyperplastic polyps of the stomach.

Female↗
PubMed2003

Clip-assisted endoscopic method for placement of a nasoenteric feeding tube into the distal duodenum.

Gastroenterologists are often frustrated in their efforts to deliver a feeding tube by endoscopic guidance into the small bowel because of retrograde migration during the withdrawal of the endoscope. We describe a clip assisted endoscopic method whereby a nasoenteric feeding tube can be reliably delivered into the distal duodenum. A nasoduodenal tube with a 3-0 silk suture sewn on its distal tip is inserted into the stomach. The suture on the feeding tube is grasped by a clip-fixing device. Then, the endoscope with feeding tube is advanced into the distal duodenum and the tube is fixed on a mucosal fold by clipping. We used this technique to successfully place nasoenteric tubes into the distal duodenum in 9 patients. There were no procedure-related complications, and no bleeding or perforation due to removal of the feeding tubes was observed. We conclude that this clip-assisted endoscopic method is a reliable modality for placing nasoenteric tubes.

Adult↗
PubMed2002

Correlation of p21 gene codon 31 polymorphism and TNF-alpha gene polymorphism with nasopharyngeal carcinoma.

Background p21 (WAF1/CIP1) is a downstream protein from p53 and can arrest the cell cycle at the G1/S phase in response to signal from p53. The most frequently seen polymorphic site is at codon 31, where a base change from AGC to AGA causes an amino acid change from serine to arginine. Tumor necrosis factor-alpha (TNF-alpha) is a cytokine that is secreted from macrophages, and is related to a sequence of events in the response to inflammation and cancer formation. The TNF-alpha gene promoter -308 G/A polymorphism has been reported to be associated with some cancers. In this study, these polymorphisms were proposed to be a candidate genetic marker of nasopharyngeal carcinoma (NPC). The distribution was analyzed in 47 NPC patients and a control group of 119 healthy people. The association of the p21 codon 31 polymorphism with NPC was detected by polymerase chain reaction (PCR) and restriction analysis by Blp I endonuclease, and calculated by the chi-square test. The TNF-alpha gene promoter -308 G/A polymorphism was identified by Nco I endonuclease. The distribution of the gene p21 codon 31 polymorphisms showed no significant difference between the two groups. The serine form of p21 codon 31 was more prominent in smokers than nonsmokers among the NPC patients (P < 0.05). There was no significant difference in the distribution of TNF-alpha gene promoter -308 G/A polymorphism between control and cancer patients. The results indicate that the gene p21 codon 31 polymorphism and TNF-alpha promoter -308 polymorphism are not correlated with NPC. However, the difference between smokers and nonsmokers suggests that an environmental factor may be involved in association with the p21 gene in the formation of NPC.

Adult↗
PubMed2002

Urokinase gene 3'-UTR T/C polymorphism is associated with urolithiasis.

OBJECTIVES: To study single nucleotide polymorphisms to investigate the possibility that urokinase is involved in the formation of urolithiasis, which, although lacking in genetic evidence, has been previously proposed. METHODS: A total of 153 patients with recurrent calcium stones and 105 controls were studied. Polymerase chain reaction-based restriction analysis was used to identify the C/T polymorphism of the urokinase gene, which is mapped on the 3'-untranslated region (3'-UTR) on chromosome 10. RESULTS: A significant difference was found in the distribution of the urokinase gene 3'-UTR C/T polymorphism frequency between patients with stones and normal controls (P <0.05). The odds ratio for the risk of the "T" allele in patients with stones was 3.088 (95% confidence interval 1.06 to 8.99). CONCLUSIONS: The results of our study demonstrate that the urokinase gene 3'-UTR "T" allele is associated with calcium stone disease. Individuals possessing the "T" allele have a higher incidence of calcium oxalate stone disease. The results of this study provide genetic evidence that the urokinase gene may play a role in stone formation.

3' Untranslated Regions↗
PubMed2002

Banding ligation versus nadolol and isosorbide mononitrate for the prevention of esophageal variceal rebleeding.

BACKGROUND & AIMS: beta-blockers and banding ligation are effective in the prevention of variceal rebleeding. However, the relative efficacy and safety remains unresolved. METHODS: One hundred twenty-one patients with a history of esophageal variceal bleeding were enrolled. Patients were randomized to undergo regular endoscopic variceal ligation (EVL group, 60 patients) until variceal obliteration, or drug therapy by using nadolol plus isosorbide mononitrate (N+I group, 61 patients) during the study period to prevent rebleeding. RESULTS: After a median follow-up period of 25 months, recurrent upper gastrointestinal bleeding developed in 23 patients in the EVL group and 35 patients in the N+I group (P = 0.10). Recurrent bleeding from esophageal varices occurred in 12 patients (20%) in the EVL group and 26 patients (42%) in the N+I group (relative risk = 0.45; 95% confidence interval, 0.24-0.85). The actuarial probability of rebleeding from esophageal varices was lower in the EVL group (P = 0.01). The multivariate Cox analysis indicated that the treatment was the only factor predictive of rebleeding. Treatment failure occurred in 8 patients (13%) in the EVL group and 17 patients (28%) in the N+I group (P = 0.01). Fifteen patients in the EVL group and 8 patients of the N+I group died (P = 0.06). Complications occurred in 17% of the EVL group and in 19% of the N+I group (P = 0.6). CONCLUSIONS: Our trial showed that ligation was more effective than nadolol plus isosorbide-5-mononitrate in the prevention of variceal rebleeding, with similar complications in both treatment modalities. However, there is no significant difference in the survival rate between the 2 groups.

Adult↗
PubMed2002

Prognostic significance of the proline form of p53 codon 72 polymorphism in nasopharyngeal carcinoma.

OBJECTIVES/ HYPOTHESIS: An important tumor suppressor gene, p53, plays a role in the regulation of cell progression and prevention of carcinogenesis. Mutated p53 is related to cell progression and malignancy. We aimed to evaluate the association between nasopharyngeal carcinoma and p53 polymorphism. STUDY DESIGN: Case control study. METHODS: All individuals were divided into two groups: nasopharyngeal carcinoma (n = 50) and non-nasopharyngeal carcinoma groups (n = 59). Their p53 codon 72 polymorphisms (arginine [Arg] homozygotes, heterozygotes, proline [Pro] homozygotes) were detected by polymerase chain reaction. Associations between nasopharyngeal carcinoma and p53 polymorphism were evaluated. RESULTS: Distributions of various p53 polymorphisms significantly differed between the two groups. We noted a dominant presentation of Pro homozygotes in the nasopharyngeal carcinoma population over that in the non-nasopharyngeal carcinoma population. Proportions of Pro homozygotes and heterozygotes and Arg homozygotes were 32%, 28%, and 40% in the nasopharyngeal carcinoma population and were 13.5%, 44.1%, and 42.4% in the non-nasopharyngeal carcinoma population, respectively. CONCLUSIONS: An association exists between nasopharyngeal carcinoma and p53 codon 72 polymorphism. The p53 Pro homozygotes are to a higher risk of development of nasopharyngeal carcinoma.

Arginine↗