Biomedical subjects

C J Chen

Publications and source records attributed to C J Chen.

At least 73 records · Page 4Linked to original sources

PubMed2001

HLA-DQA1 genotyping in patients with rheumatoid arthritis in Taiwan.

To investigate the role of HLA-DQA1 genotypes and their interaction with HLA-DRB1 in the pathogenesis of rheumatoid arthritis (RA) in Taiwan, HLA-DQA1 was determined in 71 patients with RA and 108 healthy controls by SSP-PCR method. HLA-DRB1 and HLA-DQA1 were simultaneously detected in 55 RA patients and 101 healthy controls. PCR/SSOP method was used to determine the HLA-DRB1 genotypes, and the subtypes of HLA-DR4 were determined by cloning and sequencing. The phenotypic frequency of HLA-DQA1*0301 was significantly lower in RA than in controls, and, in contrast, the HLA-DQA1*0302 and DQA1*0303 were significantly higher in RA than in controls. The associations of DQA1*0301, *0302, and *0303 with RA were independent of DR4 and DRB1*0405. Moreover, the interactions between HLA-DR4 and HLA-DQA1*0302 or DQA1*0303 could enhance the development of RA. We also found that the prevalence of bone erosion and seropositivity of rheumatoid factor (RF) were significantly higher in HLA-DQA1*0303 positive RA patients than in healthy controls. HLA-DQA1*0302 and DQA1*0303 are the risk factors for susceptibility to RA, while HLA-DQA1*0301 is a protective factor. A synergistic effect for the susceptibility to RA can be found between HLA-DR4 and HLA-DQA1*0302 or DQA1*0303. We also found that the HLA-DQA1*0303 was related to bone erosion and seropositivity of RF in RA patients.

Alleles↗

PubMed2001

Familial Mediterranean fever in a Taiwanese patient.

Familial Mediterranean fever is a rare disease characterized by cyclic attacks of fever, serositis and strong family background. Here we report a 22-year-old man who suffered from recurrent fever accompanied by chest and abdominal pain for more than 10 years. The attack frequency was about once per 2-3 weeks. Although he consulted many clinics and even received appendectomy at the age of 15, no definite diagnosis was given. During the admission, many laboratory examinations failed to show any abnormality except mild leukocytosis and elevated C-reaction protein. Image studies including chest X ray and abdominal CT scan showed negative result but, interestingly, Gallium-67 scan showed a hot spot in right lower chest and right lower abdomen. After prophylaxis with colchicine 1.0 mg per day, he has enjoyed more than 2 years without the above symptoms.

Adult↗

PubMed2001

Persistent hyperendemicity of hepatitis C virus infection in Taiwan: the important role of iatrogenic risk factors.

The purpose of this study was to investigate determinants of endemic hepatitis C virus (HCV) infection within communities in Taiwan. A two-phase study, including a seroprevalence survey and a prevalent case-control study at the first phase, which has been published previously, and a follow-up seroconversion determination and an incident case-control study during the second phase, was carried out to evaluate correlates of persistent endemic HCV infection. At the first phase, a total of 12,021 men and 1,819 women who were 30-64 years old and living in seven townships in Taiwan were tested for the seroprevalence of antibodies to HCV (anti-HCV). In addition, a prevalent case-control study involving 272 HCV-positive cases and 282 seronegative controls identified from the anti-HCV testing was conducted to investigate risk factors associated with HCV prevalence. During the second phase, a total of 2,728 men and 834 women who were seronegative at recruitment participated in the 1-year prospective study on anti-HCV seroconversion. Subsequently, an incident case-control study based on 39 seroconverters and 81 persistently seronegative controls were carried out to elucidate determinants of HCV seroconvertion. Antibodies to HCV were tested by the second-generation enzyme immunoassay. Information on risk factors of HCV infection was collected from subject interviews. The prevalence of anti-HCV consistently increased with age (range 2.9-5.4%), whereas no apparent age trend was observed for anti-HCV seroconversion rate (range 0.9-1.7%). A striking geographical variation in seroprevalence and seroconversion rates of anti-HCV was observed in the study townships. Furthermore, a significant geographical correlation between HCV seroprevalence and seroconversion rates was noted (r = 0.962, P = 0.001). From the results of both prevalent and incident case-control comparisons, medical injections were found to be the main mode to sustain the persistent endemic state of HCV infection within a community (odds ratios for prevalent and incident case-control studies were 2.5 (95% CI = 1.7-3.6) and 3.1 (95% CI = 1.4-7.1), respectively. The data indicate that the basis for HCV transmission has already been existed in study areas and the iatrogenic risk factor tended to be the major determinant for sustaining persistent endemicity within a community.

Adult↗

PubMed2001

Tumor necrosis factor promoter polymorphisms in patients with rheumatoid arthritis in Taiwan.

OBJECTIVE: To investigate the association of tumor necrosis factor (TNF) promoter polymorphisms with rheumatoid arthritis (RA) in Taiwan. METHODS: TNF promoter polymorphisms at positions -238, -244, -308, -376, -857, and -863 were determined in 97 patients with RA and 97 healthy controls using the PCR-RFLP method. RESULTS: The phenotypic frequency of TNF-308A was significantly lower in patients with RA than in healthy controls. This finding can only be found in HLA-DR4 negative patients, not in DR4 positive RA patients and controls. The TNF promoter polymorphisms at positions -238, -244, -308, -376, -857, and -863 were not related to the clinical manifestations of RA patients. CONCLUSION: TNF-308A itself or a neighboring gene may be a protective factor for the development of RA in the HLA-DR4 negative population in Taiwan. TNF promoter polymorphisms were not associated with the clinical manifestations of patients with RA in Taiwan.

Arthritis, Rheumatoid↗

PubMed2001

Arginase levels are increased in patients with rheumatoid arthritis.

Arginase and nitric oxide synthase (NOS) compete for the same substrate, L-arginine. The reciprocal regulation of arginase and NOS in L-arginine-metabolizing pathways has recently been demonstrated. Since NOS is involved in the inflammation of human arthritides, we hypothesized that this reciprocal regulation might also occur within the inflamed synovium. The present study shows that both serum arginase activity and protein levels were significantly higher in patients with rheumatoid arthritis (RA) than in patients with systemic lupus erythematosus (SLE) or osteoarthritis (OA) or in healthy controls. Arginase protein concentrations in supernatants of monocyte cultures from RA patients were also significantly higher than in those from SLE or OA patients or healthy controls. In RA patients, there was a significant correlation between the serum concentrations of arginase protein and rheumatoid factor (r = 0.82, p < 0.0001). These data indicate that increased arginase production is seen in RA patients, but not in other immune-related diseases, suggesting that increased arginase production is unique to, and may play an important role in, the pathogenesis of RA disease.

Arginase↗

PubMed2001

Occupational exposure to wood, formaldehyde, and solvents and risk of nasopharyngeal carcinoma.

Our objective was to evaluate the link between occupational exposures to wood dust, formaldehyde, and solvents and the development of nasopharyngeal carcinoma (NPC). A case-control study was conducted among 375 newly diagnosed cases of NPC in Taipei, Taiwan, and 325 community controls matched to cases on sex, age, and geographical residence (99 and 87% response rates, respectively). Most cases (>90%) were diagnosed with WHO Types 2 or 3 (nonkeratinizing and undifferentiated carcinomas), whereas the remaining cases were diagnosed with WHO Type 1 (squamous cell carcinomas). A complete occupational history was obtained via a personal interview and blindly assessed by an industrial hygienist for intensity and probability of exposure to wood dust, formaldehyde, and solvents. Information on socio-demographic characteristics, cigarette smoking, dietary consumption of nitrosamines, and other potential confounding factors was obtained via a personal interview. Blood specimens were tested for human leukocyte antigen class I/II genotypes, polymorphisms in cytochrome P450 2E1 genotype, and various anti-EBV antibodies known to be associated with NPC. Analysis was performed using logistic regression; relative risk (RR) estimates and 95% confidence intervals (CI) were calculated. Individuals exposed to wood dust had an adjusted RR of 1.7 (95% CI = 1.0-3.0). Those exposed to wood dust for >10 years had an adjusted RR of 2.4 (95% CI = 1.1-5.0; p(trend) = 0.02). Risk was strongest for those first exposed before the age of 25 years and those seropositive to EBV. Individuals exposed to formaldehyde were at a more modest and nonsignificant increased risk of NPC (RR = 1.4; 95% CI = 0.93-2.2). Those exposed to formaldehyde for >10 years had an adjusted RR of 1.6 (95% CI = 0.91-2.9). The association between formaldehyde and NPC was stronger in analyses restricted to EBV seropositive individuals (RR = 2.7; 95% CI = 1.2-5.9). However, no dose response was observed with increasing duration or cumulative use. No association was observed between solvent exposure and NPC (RR = 1.2; 95% CI = 0.86-1.7). Occupational exposure to wood dust is likely to be involved in the development of NPC, a finding that is consistent with the known link between wood exposure and nasal adenocarcinomas. Formaldehyde exposure is less clearly linked to NPC, whereas exposure to solvents is unlikely to be involved in NPC pathogenesis.

Adolescent↗

PubMed2001

Association of aflatoxin B(1)-albumin adduct levels with hepatitis B surface antigen status among adolescents in Taiwan.

Chronic hepatitis B virus (HBV) infection and aflatoxin B(1) (AFB(1)) exposure interact synergetically to induce hepatocellular carcinoma. One suggested mechanism for this interaction is the enhanced activation of AFB(1) in chronically HBV-infected individuals. Whereas no associations between chronic HBV infection and AFB(1)-albumin adducts were observed in several studies in adults, hepatitis B surface antigen (HbsAg)-positive children were found to have elevated adducts in Gambia. To assess the association between chronic HBV infection and AFB(1)-albumin adduct level in Taiwan, 200 junior high school adolescents from 20 townships were assayed for HBsAg and AFB(1)-albumin adducts. The mean AFB(1)-albumin adduct level was higher in HBsAg-positive compared with HBsAg-negative subjects. The association between HBsAg status and AFB(1)-albumin adducts remained after multivariate adjustment. This finding additionally supports the synergetic interaction between HBV and AFB(1), but the mechanism remains to be elucidated.

Adolescent↗

PubMed2001

Epidemiologic study of the prevalence and severity of myopia among schoolchildren in Taiwan in 2000.

BACKGROUND AND PURPOSE: A nationwide survey was performed in 2000 to determine the prevalence and severity of myopia among schoolchildren in Taiwan and to compare these findings with the results of the last survey performed in 1995. METHODS: We first divided the whole island into regions according to developmental grade scores and then sampled with the probability proportional to the size of the population within each stratum. A total of 10,889 students were enrolled, including 5,664 boys and 5,225 girls, with ages ranging from 7 to 18 years. The refractive status and corneal radius of each student were measured with an autorefractometer under cycloplegia and checked with retinoscopy. Axial length was measured using biometric ultrasound. RESULTS: The myopia rate increased from 20% at 7 years, to 61% at 12 years, and 81% at 15 years. A myopic rate of 84% was found for schoolchildren aged 16 years through 18 years. The mean refractive index reached myopic status at the age of 8, and increased to -4.12 D in girls and -3.15 D in boys at the age of 18 years. The prevalence of high myopia (> -6.0 D) at the age of 18 years was 24% in girls and 18% in boys. The increase in axial length corresponded with the progression of myopia. The anterior chamber depth was slightly deeper from 7 years to 13 years and then remained stable. The lens thickness decreased from 7 years to 11 years. After age 15, further thickening of the lens was correlated with both age and severity of myopia. However, the corneal curvature was not related to age or severity of myopia. Girls had a higher prevalence and more severe degree of myopia than boys. Children in urban areas had a higher prevalence and more severe degree of myopia than children in rural areas. CONCLUSION: The prevalence and severity of myopia in schoolchildren in Taiwan in 2000 increased compared to 1995, with the most severe increases occurring in younger age groups. Thus, preventing schoolchildren developing myopia at a young age may slow down the increase in severity of myopia in Taiwan.

Adolescent↗

PubMed2001

Systemic lupus erythematosus complicated by recurrent spontaneous pneumothorax--a case report.

Despite frequent pleuro-pulmonary involvement, spontaneous pneumothorax is rare in patients with systemic lupus erythematosus (SLE). Here, we report a 17-year-old female patient with SLE, complicated by multiple organs involvement. She initially presented with interstitial pneumonitis and pulmonary hemorrhage, followed by spontaneous pneumothorax and CNS involvement. The patient was treated with immunosuppressive agents, including steroid and cyclophosphamide pulse therapies. Spontaneous pneumothorax happened to her once again at a different location during treatment. After aggressive therapy, the disease activity of SLE gradually diminished, and pneumothorax had not recurred during the further follow-up. Therefore, the pneumothorax may occur in SLE patients with high disease activity.

Adolescent↗

PubMed2001

A school waterborne outbreak involving both Shigella sonnei and Entamoeba histolytica.

In an outbreak of gastroenteritis affecting 730 students, Shigella sonnei and Entamoeba histolytica were isolated from the stool specimens of patients. Environmental investigations revealed the source of infection to be contamination of underground well water by sewage from a toilet. The outbreak ended with the closure of the well water supply. To avoid such problems, institutions and other groups that maintain their own wells, including schools and summer camps, need to be vigilant about maintenance and check for potential contamination.

Animals↗

PubMed2000

Hepatitis B vaccination and hepatocellular carcinoma rates in boys and girls.

CONTEXT: Hepatocellular carcinoma (HCC) has a male predominance and is closely related to hepatitis B virus (HBV) infection. Hepatitis B virus vaccination was launched in 1984 in Taiwan for neonates of mothers carrying hepatitis B e antigen, resulting in a decreased incidence of HCC in children. The effect on boys vs girls is not known. OBJECTIVE: To evaluate the association between a HBV vaccination program with incidence of childhood HCC by sex. DESIGN AND SETTING: Analysis of data collected from Taiwan's National Cancer Registry System and the Taiwan Childhood Hepatoma Study Group between 1981 and 1996. PARTICIPANTS: Children aged 6 to 14 years who were diagnosed as having HCC (201 boys and 70 girls). MAIN OUTCOME MEASURE: Incidence of HCC in boys and girls before and after implementation of the vaccination program. RESULTS: The boy-girl incidence ratio decreased steadily from 4.5 in 1981-1984 (before the program's introduction) to 1.9 in 1990-1996 (6-12 years after the vaccination program was launched). The incidence of HCC in boys born after 1984 was significantly reduced in comparison with those born before 1978 (relative risk [RR], 0.72; P =.002). No significant decrease in HCC incidence was observed in girls born in the same periods (RR, 0.77; P =.20). The incidence of HCC in boys remained stable with increasing age, while an increase of HCC incidence with age in girls was observed. These age and sex effects remained the same regardless of birth before or after the vaccination program. CONCLUSION: Our results suggest that boys may benefit more from HBV vaccination than girls in the prevention of HCC.

Adolescent↗

PubMed2000

Androgen-receptor gene CAG repeats, plasma testosterone levels, and risk of hepatitis B-related hepatocellular carcinoma.

BACKGROUND: Worldwide, hepatocellular carcinoma (HCC) is more prevalent in men than in women, suggesting that sex hormones and/or X-chromosome-linked genes may be involved in hepatocarcinogenesis. We investigated the association of a trinucleotide (CAG) repeat in the androgen receptor (AR) gene (located on the X chromosome) termed "AR-CAG repeats," levels of plasma testosterone, and the risk of HCC in Taiwanese men. Chronic hepatitis B virus (HBV) infection, which is associated with risk of HCC, is hyperendemic in Taiwan. METHODS: We compared the number of AR-CAG repeats in 285 HBV carriers with HCC and in 349 HBV carriers without HCC. We also conducted a nested case--control study on participants in a cohort study. Blood was collected prospectively from 110 case patients and 239 control subjects and was used to determine the number of AR-CAG repeats and plasma testosterone level. All statistical tests were two-sided. RESULTS: The overall odds ratio (OR) for HCC was 1.72 (95% confidence interval [CI] = 1.03--2.89) for HBV carriers with 20 or fewer AR-CAG repeats compared with those with more than 24 repeats. This association was observed only in patients with late-onset HCC (OR = 2.37; 95% CI = 1.28--4.38). In the nested case-control study, HBV carriers in the highest tertile of testosterone levels had a statistically significantly increased risk of HCC (OR = 2.06; 95% CI = 1.14--3.70) compared with those in the lowest tertile. Elevated testosterone was more strongly associated with early-onset (OR = 4.67; 95% CI = 1.41--15.38) than late-onset disease. HBV carriers with 20 or fewer AR-CAG repeats and higher testosterone levels had a fourfold increase in HCC risk compared with those with more than 24 repeats and testosterone levels in the lowest tertile. CONCLUSIONS: Higher levels of androgen signaling, reflected by higher testosterone levels and 20 or fewer AR-CAG repeats, may be associated with an increased risk of HBV-related HCC in men.

Adenine↗

PubMed2000

An optical technique to determine the total collection efficiency of a cylone.

An experimental method is proposed to determine the total collection efficiency of a cyclone. An optical technique is utilized to measure and calculate the total collection efficiency by integrating the area below the size distribution curve upstream and downstream of the cyclone by a particle counter-sizer-velocimeter. The results show that the size distribution upstream and downstream of the cyclone is almost a smooth curve. It could be used to calculate the total collection efficiency. The measured total efficiency by the particle counter-sizer-velocimeter is 2-3% higher than that measured by the weighing method. This close agreement between the two methods suggests that the total collection efficiency may be determined by the optical technique.

Air Movements↗

PubMed2000

Genetic polymorphisms of p53 and GSTP1,but not NAT2,are associated with susceptibility to squamous-cell carcinoma of the esophagus.

The interaction of genetic and environmental factors can determine an individual's susceptibility to various cancers. We present a hospital-based case-control study, which included 90 patients of esophageal squamous-cell carcinoma (ESCC) and 254 healthy people in Taiwan, to investigate the effects of genetic polymorphisms of p53, GSTP1 and NAT2 on the risk of ESCC. Polymorphisms of p53, NAT2 and GSTP1 were determined by PCR-RFLP. The codon 72 p53 Pro allele was more frequently found in ESCC patients [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.04-3.35 for Arg/Pro genotype and OR 2.56, 95% CI 1.29-5.08 for Pro/Pro genotype]. In cigarette smokers, the frequency of GSTP1 Ile/Ile genotype was higher in ESCC patients (OR 2.8, 95% CI 1.4-5.7). Among alcohol drinkers, borderline significance was also found for GSTP1 Ile/Ile genotype (OR 2.0, 95% CI 0.9-4.4). Results were not similar for the NAT2 genetic polymorphism. Using logistic analyses, we found that individuals with p53 Pro/Pro genotype had a significantly higher risk of developing ESCC than those with Arg/Arg genotype (OR 2.3, 95% CI 1. 1-5.1), after adjusting for other significant environmental risk factors. This result remained similar (OR 2.2, 95% CI 1.0-4.8 for p53 Pro/Pro vs. Arg/Arg), even after further adjustment for NAT2 and GSTP1 polymorphisms. The codon 72 p53 Pro/Pro genotype in the general population and GSTP1 Ile/Ile in cigarette smokers may predict a higher risk of developing ESCC.

Adult↗

PubMed2000

PAX8-PPARgamma1 fusion oncogene in human thyroid carcinoma [corrected].

Chromosomal translocations that encode fusion oncoproteins have been observed consistently in leukemias/lymphomas and sarcomas but not in carcinomas, the most common human cancers. Here, we report that t(2;3)(q13;p25), a translocation identified in a subset of human thyroid follicular carcinomas, results in fusion of the DNA binding domains of the thyroid transcription factor PAX8 to domains A to F of the peroxisome proliferator-activated receptor (PPAR) gamma1. PAX8-PPARgamma1 mRNA and protein were detected in 5 of 8 thyroid follicular carcinomas but not in 20 follicular adenomas, 10 papillary carcinomas, or 10 multinodular hyperplasias. PAX8-PPARgamma1 inhibited thiazolidinedione-induced transactivation by PPARgamma1 in a dominant negative manner. The experiments demonstrate an oncogenic role for PPARgamma and suggest that PAX8-PPARgamma1 may be useful in the diagnosis and treatment of thyroid carcinoma.

Adenocarcinoma, Follicular↗

PubMed2000

Familial risk of hepatocellular carcinoma among chronic hepatitis B carriers and their relatives.

BACKGROUND: Familial predisposition as a risk factor for hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) carriers has not been thoroughly explored. METHODS: The HCC risk associated with having parents and/or siblings with HCC was evaluated by use of a cohort study of 4808 male HBV carriers. A case-control family study was also conducted on data from first-degree relatives of 553 HBV carriers who had newly diagnosed HCC (case subjects) and 4684 HBV carriers without HCC (control subjects). RESULTS: In the cohort study, HBV carriers with a family history of HCC had a multivariate-adjusted rate ratio for HCC of 2.41 (95% confidence interval [CI] = 1.47-3.95) compared with HBV carriers without a family history of HCC. For carriers with two or more affected relatives, the ratio increased to 5.55 (95% CI = 2.02-15.26). Cumulative HCC risk by age 70 years was 235.6 per 1000 (95% CI = 95. 3-375.9 per 1000) for HBV carriers with family history compared with 88.9 per 1000 (95% CI = 67.9-109.9 per 1000) for those without. In the case-control family study, first-degree relatives of case subjects were more likely to have HCC (age-sex-adjusted odds ratio [OR] = 2.57; 95% CI = 2.03-3.25) than first-degree relatives of control subjects. The excess risk of HCC among relatives was particularly evident in siblings (sisters-age-adjusted OR = 4.55 [95% CI = 2.22-9.31]; brothers-age-adjusted OR = 3.73 [95% CI = 2. 64-5.27]), but it was also observed in parents. The cumulative risk of HCC to age 80 years was 83.0 per 1000 among relatives of case subjects and 42.0 per 1000 among relatives of control subjects. Among relatives of case subjects, the cumulative risk of HCC was greater if the case subjects were diagnosed before age 50 years (two-sided P =.047). Liver cirrhosis was 2.29 (95% CI = 1.68-3.11) times more frequent in relatives of case subjects than in relatives of control subjects. CONCLUSIONS: First-degree relatives of patients with HBV-related HCC appear to be at increased risk of HCC and should be considered in the formulation of HCC-screening programs.

Adult↗

PubMed2000

Astrocytic alteration induced by Japanese encephalitis virus infection.

The neurotropism of Japanese encephalitis virus (EV) has not been well characterized. Astrocytes are parts of the blood-brain barrier, a major source of chemokines, and critical effectors of central inflammation. Thus, astrocytes might play some role as JEV travels from the peripheral to the CNS and/or the resultant encephalitis. Using rat cortical cultures, we found that JEV can cause cellular and/or functional changes in astrocytes as indicated by increased expression of interleukin-6 (IL-6), regulated by activation, normal T cell expressed and secreted (RANTES), and monocyte chemotactic protein 1 (MCP-1), increased lactate release and glucose uptake, and attenuation of glutamate toxicity. These modulations occur needed by the cells for compensation and may affect neuron and/or astrocyte function.

Animals↗

PubMed2000

Effects of naloxone on lactate, pyruvate metabolism and antioxidant enzyme activity in rat cerebral ischemia/reperfusion.

Whether naloxone may modulate energy metabolism and endogenous antioxidant enzyme activities in ischemic cortex was studied. Cerebral ischemia/reperfusion (I/R) was produced by occluding two common carotid arteries and the right middle cerebral artery for 90 min followed by reperfusion in anesthetized Sprague-Dawley rats. Both pre-treatment (0.03 or 0.3 mg) and post-treatment (0.3 mg) of naloxone by intracerebroventricular infusion significantly reduced cortical infarct volumes. Pre-treatment with 0.03 mg reduced ischemia-induced suppression of extracellular pyruvate level and enhancement of lactate/pyruvate ratio as well as cerebral I/R-induced increases of endogenous catalase, glutathione peroxidase, and manganese superoxide dismutase activities. In conclusion, neuroprotective effects of naloxone in terms of reducing brain infarction involve attenuation of the disturbance of cellular functions following cerebral I/R via restoration of mitochondrial activities or energy metabolism.

Animals↗