Biomedical subjects

C J Chen

Publications and source records attributed to C J Chen.

At least 145 records · Page 8Linked to original sources

PubMed1999

Seroepidemiology of human parvovirus B19 in Taiwan.

In order to determine the prevalence and risk factors of human parvovirus B19 (B19) infection in Taiwan, a seroepidemiological study was carried out in 19 townships. Serum samples were collected from 862 healthy residents, who were selected by stratified random sampling from various study areas. They were chosen from four different ethnic groups including aborigines, Fukien Taiwanese, Hakka Taiwanese, and mainland Chinese. Serum samples were screened for B19 IgG antibody by indirect antibody capture enzyme-linked immunosorbent assay (ELISA) and B19 IgM by IgM antibody capture (MAC)-ELISA, respectively. The overall prevalence of anti-B19 IgG and anti-B19 IgM was 32.8% and 0.35%, respectively. The anti-B19 seropositive rate in females was significantly higher than that of males (36.4% vs. 29.4%, P < .001). The age-sex-adjusted seropositive rate in urban townships (39.9%) was higher than that in aboriginal townships (30.5%, P < .001). The seropositive rate increased significantly with age showing a dose-response relationship (P=0.0001 based on a trend test). Blood transfusion was found to be associated with an increased seropositive rate showing a multivariate-adjusted odds ratios of 1.6.

Adolescent↗

PubMed1998

Prevalence of and factors related to pneumoconiosis among foundry workers in central Taiwan.

The objective of this study was to investigate the prevalence of and factors related to pneumoconiosis in foundry workers. Seven hundred and eighteen workers from 50 foundries in central Taiwan were interviewed using a constructed questionnaire. A full-sized PA chest radiograph was used to diagnose pneumoconiosis, according to ILO criteria. Overall, pneumoconiosis was found in 7.5% of the workers. The highest prevalence was found among furnace workers (15.9%) and molding workers (8.40%). All foundry workers except those in administrative positions had a significantly increased risk of developing pneumoconiosis. Using a multiple logistic regression, compared to administrative workers, furnace workers had the highest risk (10.63 times), followed by post-treatment workers (6.63 times), and molding workers (5.41 times). In conclusion, the prevalence of pneumoconiosis was significantly related to high concentrations of dust, especially with a high proportion of free silica, however, smoking and length of exposure were also contributing factors.

Adult↗

PubMed1998

Pulsed ultrafiltration characterization of binding.

We describe a new method for measuring binding constants, pulsed ultrafiltration. In this technique, a single injection or "pulse" of ligand is passed through a cell containing macromolecules confined by a conventional ultrafiltration membrane. Any binding of the ligand to the macromolecule alters the elution profile of the ligand. We describe this interaction by a set of coupled differential equations whose solution allows us to extract the binding density as a function of free ligand concentration eluting from the cell. A method of comparing elution profile areas which leads to values for both binding affinity and stoichiometry is also presented. We show that the pulsed ultrafiltration method can generate an extensive binding isotherm with a dense set of data points over a wide range of binding densities. We apply the method to several model ligand-macromolecule binding systems to demonstrate the measurement of equilibrium association constants and binding stoichiometry, the accuracy and precision of the method, and temperature dependence of binding. In general, our results agree with those from the literature, and they show that the approach is a fast and flexible method for characterizing ligand-macromolecule binding.

Chromatography, High Pressure Liquid↗

PubMed1998

Urinary levels of inorganic and organic arsenic metabolites among residents in an arseniasis-hyperendemic area in Taiwan.

In order to elucidate whether urinary levels of inorganic and organic arsenic metabolites are associated with previous exposure to high-arsenic artesian well water, a total of 302 residents of age 30 yr or older were recruited from three arseniasis-hyperendemic villages in Taiwan. Most study subjects had stopped consuming high-arsenic artesian well water for more than 20 yr. The mean total arsenic (Ast) determined by inductively coupled plasma mass spectrometer (ICPMS) was 267.05 +/- 20.95 microg/L, and the mean level of inorganic arsenic and its metabolites (Asi) was 86.08 +/- 3.43 microg/L. In the multivariate analysis, urinary dimethylarsinic acid (DMA) levels were significantly inversely associated with age, with women exhibiting significantly lower urinary amounts of arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), organic arsenic (Aso), and Ast compared to men. After adjustment for age and sex, previous cumulative arsenic exposure through consumption of artesian well water was significantly associated with elevated urinary levels of MMA and DMA, but not As(III) + As(V), Aso and Ast. In the multivariate analysis, the percentage of Aso in Ast was significantly higher in men than women, but this was not significantly associated with age. The percentage of As(III) + As(V) in Asi increased significantly with age, while the reverse was noted with DMA in Asi. Women had a significantly higher DMA percentage but lower As(III) + As(V) and MMA percentages in Asi than men. After adjustment for age and sex, the percentages of As(III) + As(V) in Asi were significantly inversely associated with previous arsenic exposure through consumption of artesian well water. Data suggested that women seem to possess a more efficient arsenic methylation capability than men, and aging diminishes this methylation capability; furthermore, the higher the cumulative arsenic exposure, the greater is the body burden of inorganic arsenic, mainly in the form of MMA and DMA.

Adult↗

PubMed1998

The nucleolin binding activity of hepatitis delta antigen is associated with nucleolus targeting.

Hepatitis delta antigens (HDAgs) are important for the replication and assembly of hepatitis delta virus (HDV). To understand the association between HDAgs and cellular proteins and the mechanism of viral multiplication, we have studied the interaction between HDAgs and nucleolin, a major nucleolar phosphoprotein. The interaction between HDAgs and nucleolin was first demonstrated by immunofluorescence staining studies. HDAgs and endogenous nucleolin were colocalized in the nucleoli of cultured cells transfected with plasmids encoding the small and large HDAg. Coimmunoprecipitation results indicated that the NH2-terminal domain of HDAg was essential for its binding to nucleolin. In vitro ligand binding assays revealed two nucleolin binding sites, NBS1 and NBS2. Each spanned amino acid residues 35-50 and 51-65, respectively, with a conserved core sequence K(K/R)XK. HDV replication was modulated by exogenous human nucleolin. In addition, a small HDAg mutant S-d65/75, which possesses both NBS1 and NBS2, was capable of transactivating HDV replication, whereas the small HDAg mutant S-d50/75, which retained NBS1 but not NBS2, was unable to support the replication of HDV. Thus, the nucleolin binding activity of HDAg is critical for its nucleolar targeting and is involved in the modulation of HDV replication.

Animals↗

PubMed1998

Identification of a lipoxygenase inhibitor in A431 cells as a phospholipid hydroperoxide glutathione peroxidase.

An endogenous lipoxygenase inhibitor, purified from the cytosol of human epidermoid carcinoma A431 cells, was analyzed by N-terminal microsequencing and mass spectrometric analysis. The inhibitor was purified by SDS-PAGE, then subjected to in-gel CNBr cleavage and trypsin digestion. The N-terminal sequence data obtained from a 6-8 kDa band of in-gel CNBr cleavage and the three isolated peptides of in-gel trypsin digestion, and the C-terminal peptide sequence from matrix-assisted laser desorption ionization mass spectrometry matched the sequence of human phospholipid hydroperoxide glutathione peroxidase. The purified inhibitor exhibited peroxidase activity using phosphatidylcholine hydroperoxides as the substrate. We therefore concluded that the lipoxygenase inhibitor present in A431 cells was a phospholipid hydroperoxide glutathione peroxidase.

Amino Acid Sequence↗

PubMed1998

4-Aminobiphenyl DNA damage in liver tissue of hepatocellular carcinoma patients and controls.

Epidemiologic studies have suggested that cigarette smoking is a risk factor for the development of hepatocellular carcinoma (HCC). To further investigate this relation, the authors measured levels of 4-aminobiphenyl-DNA adducts by an immunoperoxidase method in surgical liver tissues obtained between 1984 and 1995 from 105 Taiwanese patients with histologically confirmed HCC and 37 Taiwanese patients with metastatic liver tumors or intrahepatic stones. Information on clinicopathologic characteristics, cigarette smoking, and alcohol drinking was abstracted from hospital charts. Mean relative staining intensity for 4-aminobiphenyl-DNA was slightly higher in tumor tissues than in nontumor tissues obtained from HCC patients. Both mean intensities were significantly higher than the mean intensity of control tissues taken from non-HCC patients. However, no difference in mean relative staining intensity was found between smokers and nonsmokers in tissues obtained from non-HCC patients, or in tumor or nontumor tissues taken from HCC cases. After stratification of the relative staining intensities of 4-aminobiphenyl-DNA adduct levels into tertiles according to the total numbers of control tissues analyzed, there was a monotonically increasing risk of HCC. Odds ratios were 4.14 (95% confidence interval (CI) 1.15-15.50) and 9.71 (95% CI 2.82-34.86) for medium and high adduct levels compared with low adduct levels, respectively. The linear relation between adduct levels in liver tissue and HCC risk was also significant after adjustment for covariates, including hepatitis B surface antigen (HBsAg) status. The multivariate adjusted odds ratios were 3.41 (95% CI 0.82-14.25) and 6.48 (95% CI 1.59-26.50) for medium and high adduct levels, respectively. Moreover, there were monotonically increasing HCC risks for higher adduct levels in both HBsAg carriers and noncarriers. The increased risk ratios were more pronounced in noncarriers than in carriers. However, because of the small numbers of subjects, especially controls positive for HBsAg, the interaction between HBsAg status and 4-aminobiphenyl-DNA adduct level was not significant. Among HCC cases, none of the clinicopathologic characteristics were associated with relative staining intensity. These results indicate that 4-aminobiphenyl exposure, which is primarily a result of cigarette smoking, plays a role in the development of HCC in humans.

Aged↗

PubMed1998

Acupuncture treatment of urticaria.

Acupuncture has long been used to treat urticaria in the Asian world. Acute urticaria can be easily and effectively treated with acupuncture. L111 (Quchi), Sp10 (Xuehai), Sp6 (Sanyinjiao), and S36 (Zusanli) are the 4 acupuncture points most commonly prescribed. Chronic urticaria is a challenge for medical therapy. There are at least 6 kinds of acupuncture methods developed to overcome this challenge. The combination of ordinary acupuncture and auricular acupuncture has been observed to be a highly effective cure of chronic urticaria. Acupuncture point injection with thiamine hydrochloride (vitamin B1) is also an effective treatment. However, results of these clinical observations have not been systematically confirmed for lack of a control group and the need for standard classification of urticaria. Although these observational results have clinical limitations, they do offer insight into an alternative to conventional treatment of urticaria. In the future, acupuncture or acupuncturelike techniques may provide an effective alternative for treatment of patients with urticaria, particularly those refractory to medication therapy.

Acupuncture Therapy↗

PubMed1998

Antibody against the Epstein-Barr virus BHRF1 protein, a homologue of Bcl-2, in patients with nasopharyngeal carcinoma.

The Epstein-Barr virus (EBV) open reading frame BHRF1, a homologue of the oncogene bcl-2, was cloned from a patient with nasopharyngeal carcinoma (NPC) and overexpressed in Escherichia coli. The resulting recombinant BHRF1 fusion protein, with an apparent molecular weight of 35 KD, was used as antigen in an immunoblotting assay for IgG antibody in human sera. Anti-BHRF1 antibody was detected in 57 (61.3%) of 93 patients with NPC, 5 (5.7%) of 87 patients with nonmalignant diseases of the nasopharynx, and in 1 (1.3%) of 78 healthy blood donors. The positivity rate in these nonmalignant patients was 4.4 times that of the normal controls. Negative results were observed in four patients with infectious mononucleosis and patients with other cancers, including 4 with esophageal cancer, 11 with lung cancer, 10 with lymphoma, 13 with gastric carcinoma, 10 with cervical carcinoma, and 10 with other head and neck cancers. Antibody neutralizing EBV DNase and IgA antibody to viral capsid antigen (VCA) were assayed in parallel. The results showed that 7.5% of the NPC patients were negative for anti-DNase and anti-VCA antibodies and EBV infection could be detected by the anti-BHRF1 antibody alone. The demonstration of anti-BHRF1 antibody in most NPC sera strongly supports the hypothesis that the EBV BHRF1 protein is expressed in most NPC patients and its specific antibody can be a useful marker for the diagnosis of NPC.

Antibodies, Viral↗

PubMed1998

Hypoplasia of the internal carotid artery with intercavernous anastomosis.

We report a symptomatic case of unilateral hypoplasia of the internal carotid artery with an intercavernous anastomosis, a very rare developmental anomaly. The symptoms were caused by occlusion of the proximal middle cerebral artery which possibly related to the haemodynamic stress caused by the anomalous intercavernous anastomosis.

Arteriovenous Anastomosis↗

PubMed1998

Enhanced cervical MRI in identifying intracranial dural arteriovenous fistulae with spinal perimedullary venous drainage.

Diagnosis of an intracranial dural arteriovenous fistula (DAVF) with spinal perimedullary venous drainage is challenging because the presenting symptoms are usually related to dysfunction of the spine, not of the brain. Repeated spinal angiograms are usually performed before the diagnosis is finally made by cerebral angiography. We report two cases of intracranial DAVFs with spinal perimedullary venous drainage. In both cases contrast-enhanced cervical MRI demonstrated dilated lower brainstem and upper spinal veins, which, we believe, is a good indicator of the existence of such drainage. We suggest that, in cases with perimedullary serpentine enhancement on thoracic or lumbar MR images, additional Gd-enhanced cervical spinal MR imaging should be performed. The simple process of tracing the veins upwards may avoid a lot of unnecessary examinations and delay in the diagnosis.

Adult↗

PubMed1998

Congenital mesoblastic nephroma t(12;15) is associated with ETV6-NTRK3 gene fusion: cytogenetic and molecular relationship to congenital (infantile) fibrosarcoma.

Morphological, cytogenetic, and biological evidence supports a relationship between congenital (infantile) fibrosarcoma (CFS) and congenital mesoblastic nephroma (CMN). These tumors have a very similar histological appearance, and they are both associated with polysomies for chromosomes 8, 11, 17, and 20. Recently, CFS was shown to contain a novel t(12; 15)(p13;q25) translocation resulting in ETV6-NTRK3 gene fusion. The aims of this study were to determine whether congenital mesoblastic nephroma contains the t(12;15)(p13;q25) translocation and ETV6-NTRK3 gene fusion and whether ETV6-NTRK3 fusions, in CMN and CFS, antedate acquisition of nonrandom chromosome polysomies. To address these aims, we evaluated 1) ETV6-NTRK3 fusion transcripts by reverse transcriptase polymerase chain reaction and sequence analysis, 2) genomic ETV6-region chromosomal rearrangement by fluorescence in situ hybridization, and 3) chromosomal polysomies by karyotyping and fluorescence in situ hybridization. We report ETV6-NTRK3 fusion transcripts and/or ETV6-region rearrangement in five of six CMNs and in five of five CFSs. The ETV6-NTRK3 fusion transcripts and/or ETV-region chromosome rearrangements were demonstrated in two CMNs and one CFS that lacked chromosome polysomies. These findings demonstrate that t(12;15) translocation, and the associated ETV6-NTRK3 fusion, can antedate acquisition of chromosome polysomies in CMN and CFS. CMN and CFS are pathogenetically related, and it is likely that they represent a single neoplastic entity, arising in either renal or soft tissue locations.

Artificial Gene Fusion↗

PubMed1998

Low serum carotene level and increased risk of ischemic heart disease related to long-term arsenic exposure.

To elucidate the association between arsenic-related ischemic heart disease (ISHD) and serum antioxidant micronutrient level, residents aged 30 or older living in arseniasis-hyperendemic villages in Taiwan were recruited in a community-based health survey. A structured questionnaire was used to obtain a history of long-term exposure to arsenic through consuming artesian well water and fasting serum samples were also collected at the recruitment. A total of 74 patients affected with ISHD, who were diagnosed through both electrocardiography and Rose questionnaire interview, and 193 age-sex-matched healthy controls were selected for the examination of serum levels of micronutrients by high performance liquid chromatography (HPLC). There was a significant biological gradient between the risk of ISHD and the duration of consuming high-arsenic artesian well water. A significant reverse dose-response relationship with arsenic-related ISHD was observed for serum level of alpha- and beta-carotene, but not for serum levels of retinol, lycopene and alpha-tocopherol. Multivariate analysis showed a synergistic interaction on arsenic-related ISHD between duration of consuming artesian well water and low serum carotene level. An increased risk of arsenic-related ISHD was also associated with hypertension and elevated body mass index, but not with serum lipid profile, cigarette smoking and alcohol drinking. The findings seem to suggest that arsenic-related ISHD has a pathogenic mechanism which is at least partially different from that of ISHD unrelated to long-term exposure to arsenic.

Adult↗

PubMed1998

Development of an abdominal magnetic resonance (MR) contrast agent formulation with Oral Magnetic Particles (OMP, Ferristene).

A formulation for fast dispersible granules with the magnetic resonance (MR) contrast agent, Oral Magnetic Particles (OMP), was developed. The formulation contained viscosity-increasing agents (xanthan gum and a mixture of microcrystalline cellulose and sodium carboxymethylcellulose). The granules were dispersed easily in water when stirred by hand and became a viscous OMP suspension with apparent homogeneity, but does not form granule aggregates (lump), within 10 min. The dispersibiility was greatly affected by the binder type and addition of disintegrant. Hydroxypropylcellulose and low-substituted hydroxypropylcellulose were preferable. The preparation method to incorporate OMP into the granules also greatly influenced the dispersibility of the granules. A fluidized bed granulation of the base granules containing additives and subsequent coating of OMP onto the granules was eventually utilized. The formulation was able to control the viscosity of the suspension by regulating the content of viscosity-increasing agent while maintaining dispersibility. The developed formulation gave a good MR contrast image in rats and no magnetic susceptibility artifact was observed.

Abdomen↗

PubMed1998

Glaucoma after macular hole surgery.

OBJECTIVE: The study aimed to report incidence and to assess risk factors of postoperative glaucoma in patients with stage 3 idiopathic macular hole treated with pars plana vitrectomy, removal of posterior hyaloid membrane, and perfluoropropane gas tamponade. DESIGN: The author performed a retrospective chart review and statistical analysis of risk factors of postoperative glaucoma by using chi-square statistics, Fisher's exact test, and logistic regression. PARTICIPANTS: Forty consecutive patients with stage 3 idiopathic macular hole who were operated on between January 1994 and December 1995 were studied. INTERVENTION: A pars plana vitrectomy, removal of posterior hyaloid membrane, and 14% perfluoropropane gas tamponade were done to all patients. MAIN OUTCOME MEASURES: Preoperative and postoperative intraocular pressure measurements were performed. RESULTS: Twenty-one (52%) of 40 patients experienced transient intraocular pressure elevation to more than 30 mmHg. Nine (22%) had pressure elevation within 2 to 4 hours, 6 (15%) in 24 hours, and 6 (15%) in 1 week after surgery. Three patients, including one with a history of preoperative ocular hypertension, required extended topical antiglaucoma medication. Factors of age, race, gender, lens status, preoperative intraocular pressure (all preoperative intraocular pressure were 25 mmHg or less), and success in closure of macular hole were not to any statistically significant degree associated with postoperative pressure elevation. CONCLUSION: Glaucoma is a significant complication after stage 3 macular hole surgery even without adjunctive therapy. Usually happening within the first postoperative week, elevation of intraocular pressure in most cases is transient and can be controlled by medication. However, extended medication might become necessary in some cases.

Age Factors↗

PubMed1998

Endogenous cryptococcal endophthalmitis.

BACKGROUND: Occurrence of cryptococcal endophthalmitis is rare and commonly is associated with widespread disseminated diseases. The authors report here a well-documented case of endogenous cryptococcal endophthalmitis without the preceding meningeal infection. METHODS: A 45-year-old female with a history of long-term use of systemic corticosteroid and cytotoxic drugs for systemic lupus erythematosus suffered from progressive visual loss in her left eye over 1 month. Large exudative retinal detachment and severe vitreous infiltration were observed. RESULTS: Histopathologic study of the retinal biopsy specimen established the diagnosis of cryptococcal endophthalmitis. Subsequent positive histopathologic study of the aspiration vitreous smear and epiretinal membrane confirmed the recurrence and persistence of the disease over 4 months after the initial presentation. Systemic amphotericin B-fluconazole and two doses of intravitreous amphotericin B injection eliminated the infection successfully. CONCLUSION: The authors report here a well-documented case of cryptococcal endophthalmitis and present the serial clinical and histopathologic pictures. The importance of retinal biopsy in diagnosis and the combined form of antifungal treatment also are shown.

Amphotericin B↗

PubMed1998

Surgical removal of subfoveal iatrogenic choroidal neovascular membranes.

OBJECTIVE: To present the cases of two patients with laser-induced iatrogenic subfoveal choroidal neovascular membranes (CNVMs) who underwent surgical removal of the membranes with favorable outcomes. DESIGN: Interventional case reports. PARTICIPANTS: Two patients with iatrogenic subfoveal CNVM. One case developed after laser treatment for macular edema due to branch retinal vein occlusion, and the second case developed after focal laser photocoagulation for diabetic retinopathy. INTERVENTION: Surgical removal by pars plana vitrectomy. MAIN OUTCOME MEASURES: Visual acuity, scotoma, retinal examination with fundus photography, and fluorescein angiography before surgery and during the postoperative period. RESULTS: Both patients underwent surgical removal after progression of the membrane with severe visual loss of 20/200 was noted. At present follow-up, there is a significant improvement in visual acuity and a reduction in the size of the scotoma. No recurrence of CNVM is noted. CONCLUSION: Both patients with laser-induced iatrogenic subfoveal CNVM achieved a good visual outcome after surgical removal of the membrane. The reasons for a good surgical result are thought to be twofold. First, the origin of the CNVM is extrafoveal at the site of laser application. The chance for foveal cone cell damage during the surgery is reduced. Second, the degree of cellular destruction in iatrogenic CNVM is usually focal without extensive retinal photoreceptor cell and retinal pigment epithelial damage. Therefore, a better chance of postoperative visual recovery is anticipated.

Choroid↗

PubMed1998

A case-control study on risk factors for Type 1 diabetes in Taipei City.

To search for non-genetic risk factors for Type 1 diabetes among Chinese, a total of 117 Type 1 diabetes patients identified from the Taipei Type 1 Diabetes Registry and 193 frequency-matched controls with normal glucose tolerance were recruited. The controls were selected from classmates or colleagues of cases with similar distributions of age, sex, and parental and individual educational levels. Information on Type 1 diabetes risk factors was obtained through standardized interviews according to a structured questionnaire administered by two trained nurses. In the univariate analyses, the order of pregnancy of the study subject, the number of spontaneous and induced abortions reported by the mother before giving birth to the study subjects, the duration of breast-feeding and monthly family income were significantly associated with Type 1 diabetes in a dose-response manner. There was a U-shaped relationship with Type 1 diabetes for birth weight and paternal age at the conception of the study subjects. After further adjustment for multiple risk factors through logistic regression analysis, the biological gradient for pregnancy order, duration of breast-feeding, and the U-shaped relationship for paternal age remained statistically significant.

Abortion, Induced↗