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Biomedical subjects

H W Chen

Publications and source records attributed to H W Chen.

At least 19 recordsLinked to original sources
PubMed2007

B-group vitamins, MTHFR C677T polymorphism and carotid intima-media thickness in clinically healthy subjects.

OBJECTIVE: Plasma B-group vitamins and age may affect the carotid intima-media thickness (IMT) in subjects with different 677TT genotype of the methylenetetrahydrofolate reductase (MTHFR) gene. DESIGN: A hospital-based cross-study. SETTING: Genomic and Vascular Center, Changhua Christian Hospital, Changhua, Taiwan. SUBJECTS: Five hundred and forty-one clinically healthy subjects. INTERVENTION: Fasting plasma, homocysteine (Hcy), vitamin B(6), vitamin B(12), folate and B-mode carotid ultrasound. RESULTS: MTHFR genotype, plasma concentrations of folate, vitamin B(6) and vitamin B(12) and age were significantly correlated to the plasma Hcy concentration. MTHFR 677TT carriers had higher concentrations of Hcy than did subjects with the CC and CT genotypes. Age, sex, body mass index and plasma Hcy were independent contributors to increase carotid IMT. However, with stratification by mean value of age and B-group vitamins concentrations, we found that at advanced age, lower plasma folate and vitamin B(12) were three risk factors involved in the enhancing effect of the MTHFR 677TT genotype on the increase of plasma Hcy and carotid IMT. CONCLUSION: MTHFR 677TT-related carotid atherosclerosis was only identified in healthy elderly subjects with lower level of plasma folate and vitamin B(12). SPONSORSHIP: Changhua Christian Hospital.

Adult↗
PubMed2006

Characteristics of natural organic matter degradation in water by UV/H2O2 treatment.

This study evaluated the UV/H2O2 system for degradation of natural organic matter in water. The photolysis experiments were conducted in a 10-l batch reactor using a 450-watt high-pressure mercury vapor lamp as the light source. The addition of H2O2 in water greatly improved the rate of humic acid degradation by UV light and 90% of the humic acid was removed within 30 min of photolysis. Kinetic data showed that the first-order reaction could be used to describe the kinetics of both humic acid oxidation and H2O2 decomposition, and the optimum H2O2 dose was 0.01%-0.05% for humic acid oxidation. It was also observed that the absorption of UVC (UV with wavelength between 200 and 280 nm) is responsible for the dissociation of H2O2 to generate the reactive hydroxyl radicals. Depending on the initial dosages, the H2O2 added to the system can be completely decomposed by UV within 50 to 90 minutes. Upon UV irradiation, the humic intermediates with smaller molecular sizes increase as a result of the degradation of larger humic substances. Photolysis of surface water also shows that the UV/H2O2 was effective in reducing trihalomethanes (THMs) formation in treating surface water with high contents of organic precursors. The distribution of THMs shifted from chlorine-THMs to bromine-THMs after UV/H2O2 treatments when bromide was present in water. However, higher H2O2 dosages would be necessary for the photolysis of surface water containing high concentrations of organic THM precursors. As observed from the Fourier transform infrared (FTIR) spectra, the functional groups of treated humic acids were destructed significantly, including -OH (from -COOH and -COH), aromatic -C=C, and -C=O conjugated with aromatic rings.

Hydrogen Peroxide↗
PubMed2005

Identification, cloning, and expression of potential diagnostic markers for Q fever.

The clinical diagnosis of Q fever is difficult. Whole cell antigens are currently used in several serological methods, but antigens are limited due to the hazardous nature of Coxiella burnetii cultivation. In this report, we described the method of detecting immunodominant antigens of C. burnetii by using proteomic techniques with patient sera, and cloning and expressing the selected antigens using a novel vector known for its ease of expression, purification, and downstream application.

Antigens, Bacterial↗
PubMed2004

Isolation and selection of ionophore-tolerant Eimeria precocious lines: E. tenella, E. maxima and E. acervulina.

Eimeria parasites were isolated from Nanhai Guangdong province (southern China) and studied in chickens in wire cages to evaluate their drug resistance against commonly used ionophores: monensin (100 mg/kg of feed), lasolacid (90 mg/kg), salinomycin (60 mg/kg), maduramicin (5 mg/kg) and semduramicin (25 mg/kg). Chinese Yellow Broiler Chickens were infected with 40,000 crude sporulated Eimeria oocysts at 15 days of age and prophylactic medication commenced a day prior to infection. Drug resistance was assessed for each ionophore drug by calculating the anticoccidial index (ACI) and percentage optimum anticoccidial activity (POAA) based on relative weight gain, rate of oocyst production and lesion values. Results revealed that Nanhai Eimeria oocysts comprising of E. tenella, E. maxima and E. acervulina, were resistant to monensin, sensitive to both salinomycin and lasolacid and partially sensitive to maduramicin and semduramicin. By selection for early development of oocysts during passage through chickens, the prepatent time of E. tenella, E. maxima and E. acervulina were reduced by 49, 36 and 22 h, respectively. The precocious lines are less pathogenic than the parent strains from which they were selected and conferred a satisfactory protection for chickens against coccidiosis. These ionophore-tolerant precocious lines could have wider applications in the development of anticoccidial vaccines for sustainable control of coccidiosis.

Animals↗
PubMed2004

Primary lung carcinoma metastatic to a solitary fibrous tumor.

We report the case of a 78-year-old man with a 2 month history of newly diagnosed metastatic lung adenocarcinoma, who presented with a left gluteal soft tissue mass. Histological examination of the mass revealed a solitary fibrous tumor containing metastases from adenocarcinoma.

Adenocarcinoma↗
PubMed2002

Collagenase-2 (MMP-8) and collagenase-3 (MMP-13) in adult periodontitis: molecular forms and levels in gingival crevicular fluid and immunolocalisation in gingival tissue.

AIM: To determine the cellular and molecular forms of MMP-8 (collagenase-2) and MMP-13 (collagenase-3) associated with chronic adult periodontitis by examining the species present in gingival crevicular fluid (GCF) and enzyme distribution in gingival tissue. METHODS: 30-s GCF samples were collected directly from the periodontal pockets of 12 untreated patients using filter paper strips. After elution into buffer, the samples were examined by Western immunoblotting with polyclonal antibodies for MMP-8 and MMP-13 and quantification by scanning image analysis. Individual band intensities were expressed as a percentage of total sample absorbance and mean patient values were calculated. Gingival tissue from 6 patients was fixed in formalin and embedded in paraffin wax. MMP-8 and MMP-13 were localised using the same antibodies and an avidin-biotin-peroxidase detecting system. Double staining was performed with a contrasting substrate reaction. RESULTS: The majority of MMP-8 staining in pre-treatment GCF was present in 80, 75 and 60 kD bands corresponding to prepro-, pro- and active forms of PMN-type enzyme. 43 and 38 kD bands evidently represented active, fibroblast-type MMP-8. Immunoreactivities at >100 kD and < or =30 kD were probably enzyme-inhibitor complex and degraded fragments, respectively. MMP-13 was seen mainly as 60 kD proenzyme with some 40 kD active enzyme and a small proportion of >100 kD complex. The percentages of MMP-8 PMN-type enzyme and MMP-13 proenzyme bands correlated significantly with gingival and bleeding indices (p<0.05). Immunohistochemistry demonstrated MMP-8 in PMNs, sulcular epithelial and also plasma cells in inflamed gingival connective tissue. MMP-13 immunoreactivity was detected in the sulcular epithelium and in macrophage-like cells. CONCLUSION: Multiple species and elevated levels of both MMP-8 and MMP-13 from many rather than single cellular sources in the diseased periodontium are identified in untreated periodontitis GCF and active forms contribute to GCF collagenase activity.

Adult↗
PubMed2002

Removal of dissolved natural organic matter from source water with alum coagulation.

In this study, the effectiveness of enhanced alum coagulation for removal of natural organic matter (NOM) at various alum dosages and pH conditions was assessed for three source waters. Results from the laboratory jar tests at various conditions were compared. Tested pH ranged from 5.0 to 8.0, with alum dosages ranging from 60-120 mg l(-1) for removal of dissolved NOM with various concentration of dissolved organic carbon (DOC) and alkalinity. Alum coagulation profiles of the three source waters were also compared. For Cheng-Kung Water Treatment Plant (high DOC, high alkalinity), laboratory tests showed 50% DOC removal with alum dosage of 70-110 mg (-1). after acidifying the raw water to pH = 6. For Tai Lake Water Treatment Plant (high DOC, low alkalinity), laboratory tests showed that the highest DOC removal (approximately 50%) was achieved at an alum dosage of 80 mg l(-1) at pH = 8 (natural condition). However, alum coagulation showed little DOC removal for source water from Kee-Lung River (low DOC, low alkalinity). Higher alkalinity in Cheng-Kung Reservoir accounts for the necessity to acidify the raw water before enhanced coagulation for optimum DOC removal.

Alum Compounds↗
PubMed2001

Catalyzed UV oxidation of organic pollutants in biologically treated wastewater effluents.

A batch reactor was used to evaluate the efficiency of advanced oxidation process of the organic pollutants in biologically treated wastewater effluents with UV/H2O2. A 450-W high-pressure mercury vapor lamp was used as the light source. During the degradation process, the concentration of the dissolved organic compounds could be increased by more than twofold due to the decomposition of microorganisms. This increase of the dissolved organic compounds was eliminated if the water was filtered before the photodegradation experiments. It is observed that the UV alone could play a role for the oxidation of the organic pollutants; however, the addition of a small amount of hydrogen peroxide promotes the degradation efficiency of organic compounds in wastewater. The best oxidation efficiency was obtained when the water samples were under acidic conditions (pH 5), and the rate of degradation was not enhanced with the increasing H2O2 dosages. The optimum H2O2 dose was between 0.01% and 0.1% for the oxidation processes in this study. The presence of the carbonate/bicarbonate ions in water inhibits the degradation of the organic compounds.

Biodegradation, Environmental↗
PubMed2001

Capillary electrophoresis study on the micellization and critical micelle concentration of sodium dodecyl sulfate. Influence of solubilized solutes.

The influence of solubilized solutes on the micellization and critical micelle concentration (CMC) of sodium dodecyl sulfate (SDS) were investigated by means of capillary electrophoresis (CE). Three different structural types of test solutes, including chloropyridines. chlorophenols and cephalosporins with different binding strength to SDS micelles, were selected in this study. The variations of the effective electrophoretic mobility of these solutes as a function of SDS concentration in the premicellar and micellar regions were analyzed. Interestingly, the results indicate that, in the presence of these solubilized solutes, the micellization of SDS may occur over a range of SDS concentration, with the aggregate size increasing over this range. Depending on the nature of solubilized solutes and the extent of the interactions between solubilized solutes and SDS micelles, the CMC value of SDS may vary significantly. The incorporation of solubilized solutes into SDS micelles to form mixed micelles is proposed to interpret the migration behavior of solubilized solutes in CE.

Cefazolin↗
PubMed2001

Suppression of immune response and protective immunity to a Japanese encephalitis virus DNA vaccine by coadministration of an IL-12-expressing plasmid.

IL-12 plays a central role in both innate and acquired immunity and has been demonstrated to potentiate the protective immunity in several experimental vaccines. However, in this study, we show that IL-12 can be detrimental to the immune responses elicited by a plasmid DNA vaccine. Coadministration of the IL-12-expressing plasmid (pIL-12) significantly suppressed the protective immunity elicited by a plasmid DNA vaccine (pE) encoding the envelope protein of Japanese encephalitis virus. This suppressive effect was associated with marked reduction of specific T cell proliferation and Ab responses. A single dose of pIL-12 treatment with plasmid pE in initial priming resulted in significant immune suppression to subsequent pE booster immunization. The pIL-12-mediated immune suppression was dose dependent and evident only when the IL-12 gene was injected either before or coincident with the pE DNA vaccine. Finally, using IFN-gamma gene-disrupted mice, we showed that the suppressive activity of the IL-12 plasmid was dependent upon endogenous production of IFN-gamma. These results demonstrate that coexpression of the IL-12 gene can sometimes produce untoward effects to immune responses, and thus its application as a vaccine adjuvant should be carefully evaluated.

Animals↗
PubMed2001

Effect of alisol B acetate, a plant triterpene, on apoptosis in vascular smooth muscle cells and lymphocytes.

Glucocorticoid-induced apoptosis is a well-recognized physiological regulator of T-cell number and function. Alisol B acetate, a triterpene from Alisma Plantago-aquatica, has a glucocorticoid-like structure, and may have a similar function like glucocorticoid-induced apoptosis in both vascular smooth muscle cell line (A7r5) and human acute lymphoblastic leukemia cell line (CEM cells). For exploring its mechanism, mitochondria membrane potential and apoptosis-related gene expression were discussed. Alisol B (10(-6)-10(-4) M) inhibited serum-stimulated DNA synthesis in a concentration-dependent manner (IC50) = 4.0 +/- 0.8 x 10(-6) M in A7r5 and 2.1 +/- 1.2 x 10(-6) M in CEM cells). The cell viability was reduced at 10(-4) M of alisol B. Similar results were seen in dexamethasone treatment (a synthetic glucocorticoid, 10(-6) M, 48 h). Apoptosis was induced after the cells were exposed to 10(-5)-10(-4) M alisol B or 10(-6) M dexamethasone for 48 h. The mitochondrial membrane potential (delta psi(m)) was significantly reduced after the alisol B treatment, indicating that the mitochondria might play a role in the alisol B induced cell apoptosis. Alisol B (10(-5)-10(-4) M) increased the levels of c-myc and bax mRNA and proteins, but not on the anti-apoptotic proto-oncogene, bcl-2, in A7r5 and CEM cells. In contrast, dexamethasone (10(-6) M) treatment only caused significant increase in c-myc mRNA levels. These results suggest that the increased ratio of Bax/Bcl-2 and the decreased mitochondrial membrane potential might be involved in the mechanisms of alisol B-induced cell apoptosis.

Analysis of Variance↗
PubMed2001

A capillary electrophoresis study on the influence of beta-cyclodextrin on the critical micelle concentration of sodium dodecyl sulfate.

The influence of beta-cyclodextrin (beta-CD) on the critical micelle concentration (CMC) of sodium dodecyl sulfate (SDS) was investigated by capillary electrophoresis using anionic chlorophenols as probe molecules at pH 7.0. The variations of the electrophoretic mobility of probe molecules as a function of surfactant concentration in both premicellar and micellar regions in the absence and presence of beta-CD was analyzed. The results indicate that, as a consequence of a strong inclusion complexation between beta-CD and SDS, the encapsulation of beta-CD with probe molecules is greatly diminished, or even vanished, in the presence of SDS. The complexes formed between beta-CD and SDS monomers exist predominantly in the form of a 1:1 stoichiometry, while the complexes with a 2:1 stoichiometry reported previously in the literature as a minor component may exist by less than 10%. The elevation of the CMC value of SDS depends not only on the concentration of beta-CD in the buffer electrolyte but also on methanol content in the sample solution. The binding constants of probe molecules to beta-CD, to surfactant molecules, and to the complexes formed between beta-CD and SDS are reported.

Cyclodextrins↗
PubMed2001

Optimization of separation and migration behavior of chloropyridines in micellar electrokinetic chromatography.

The separation and migration behavior of pyridine and eight chloropyridines, including three monochloropyridines, four dichloropyridines, and 2,3,5-trichloropyridine were investigated by micellar electrokinetic chromatography using either sodium dodecyl sulfate (SDS) as an anionic surfactant or SDS-Brij 35 mixed micelles. Various parameters such as buffer pH, SDS concentration, Brij 35 concentration and methanol content that affect the separation were optimized. Complete separation of these chloropyridines was optimally achieved with a phosphate buffer containing SDS (30 mM) and methanol (10%, v/v) at pH 7.0. The resolution and selectivity of analytes could be considerably affected by the addition of methanol and/or Brij 35 to the background electrolyte. The migration order of these chloropyridines depends primarily on their hydrophobicity. However, electrostatic interactions may also play a significant role in the determination of the migration order of the positional isomers of chloropyridines.

Buffers↗
PubMed2001

Assessing pollution prevention program by QUAL2E simulation analysis for the Kao-Ping River Basin, Taiwan.

Wise and sustainable uses of water resources are essential for an effective river-basin-management planning. Recent management strategy further addresses the fact that quantity and quality of water are closely interrelated, and both must be considered simultaneously for all water resources and water quality management practices. The aim of this paper is to explore the impacts of water resources redistribution and pollution prevention actions between and within river basins simultaneously in South Taiwan. Much emphasis will be placed on assessing the impacts of water transfer over natural boundary to satisfy the needs of industrial development in the Tseng-Wen River system and its resultant influence on the water quality in the downstream area of the Kao-Ping River system where the pollution prevention program is to be implemented. The Kao-Ping River was further characterized hydraulically and environmentally, based on a full investigation of discharges and withdrawals in the river reaches. QUAL2E was successfully calibrated and validated using data collected between 1998 and 1999, and the model was capable of predicting the concentrations of biochemical oxygen demand, dissolved oxygen, total phosphate-phosphorus, and ammonia-nitrogen (NH3-N) for the entire river system. With the aid of QUAL2E simulation model, it shows eliminating the pig farming activities and constructing the sewer systems in the upstream area of Kao-Ping River cannot guarantee the full compliance with water quality standards in the downstream area and water transfer in the upstream area further increases negative impacts on the water quality in the wet season. The predicted situation of water quality in the dry season may even present worse condition. Additional water pollution control policy, such as the use of economic instruments, for controlling and reducing the waste-load of biochemical oxygen demand and ammonia-nitrogen is needed in the Kao-Ping River system in the long run.

Animal Husbandry↗
PubMed2001

Identification of river water quality using the fuzzy synthetic evaluation approach.

Proper identification of water quality conditions in a river system based on limited observations is an essential task for meeting the goals of environmental management. Various classification methods have been used for estimating the changing status and usability of surface water in river basins. However, a discrepancy frequently arises from the lack of a clear distinction between each water utilisation mode, the uncertainty in the quality criteria employed and the vagueness or fuzziness embedded in the decision-making output values. Owing to inherent imprecision, difficulties always exist in some conventional methodologies when describing integrated water quality conditions with respect to various chemical constituents, biological aspects, nutrients, and aesthetic qualities. This paper presents a comparative study using three fuzzy synthetic evaluation techniques to assess water quality conditions in comparison to the outputs generated by conventional procedures such as the Water Quality Index (WQI). Based on a set of data collected at seven sampling stations, a case study for the Tseng-Wen River system in Taiwan was used to demonstrate their application potential. The findings clearly indicate that the techniques may successfully harmonise inherent discrepancies and interpret complex conditions. A further, newly developed fuzzy synthetic evaluation approach described in this paper might also be useful for verifying water quality conditions for the Total Maximum Daily Load (TMDL) program and be helpful for constructing an effective water quality management strategy.

Conservation of Natural Resources↗
PubMed2001

Heat shock pretreatment influences the expression of PKC isoforms during sepsis.

Protein Kinase C (PKC) plays a central role in signal transduction and participates in diverse biological and biochemical functions. PKC dysfunction leads to general immunosuppression that, in turn, increases host susceptibility to infection and sepsis. In our previous study, we demonstrated that the mortality of sepsis is significantly decreased in rats treated with heat shock. It was considered that the modulation of PKC content by previous heat shock might contribute to the resistance to a severe infection. In this study, we attempted to understand the change of various PKC isoforms in the lymphocytes during sepsis and to investigate the role of previous heat shock in influencing PKC expression. Cecal ligation and puncture (CLP) was used as the experimental sepsis model for its biphasic clinical manifestation. Heat shock protein and PKC isoforms were detected by immunochemical study. Ten PKC isoforms (alpha, beta, gamma, delta, epsilon, zeta, theta, iota, lambda, and mu) were detected from peripheral lymphocytes. Results showed that all the PKC isoforms have a declination tendency along with the progression of CLP-induced sepsis, and previous heat shock treatment could prevent the declination of PKC content, particularly the isoforms beta, gamma, and epsilon, during sepsis. We suggest that heat shock response may participate in maintenance of PKC expression and contribute to decrease the severity of systemic infection.

Animals↗