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Biomedical subjects

C C Chou

Publications and source records attributed to C C Chou.

At least 19 recordsLinked to original sources
PubMed2006

Characterization of bacterial susceptibility isolates in sixteen dairy farms in Taiwan.

Bacteria were isolated from dairy cows, dairy farm environments, and dairy workers in 2 geographically different areas of eastern and northern Taiwan. Isolates were evaluated for antimicrobial susceptibility and the phylogenetics of isolated Escherichia coli O157:H7 were characterized. A total of 1,346 bacteria were identified, including 226 E. coli, 30 Pseudomonas spp. (7 Pseudomonas aeruginosa), 259 other gram-negative bacteria, 271 Enterococcus spp., 314 Staphylococcus spp., 195 Streptococcus spp., and 51 other gram-positive bacteria. Among them, 88% (1,184/1,346) of the isolates were resistant to sulfadimethoxine. The percentages of gram-negative bacteria resistant to oxy-tetracycline and streptomycin were 48% (249/515) and 78% (404/515), respectively. Gram-positive bacteria isolated from eastern Taiwan, the least polluted region of Taiwan, were found to have greater antimicrobial resistance than those isolated from northern Taiwan. Two E. coli O157:H7 from 2 different geographical areas were isolated. Both were vt2-positive but vt1-negative and had phylogenetic similarities of 82 and 67%, respectively, compared with previous isolates. Information on antimicrobial susceptibility revealed from this dairy farm survey may serve as a baseline for future studies and may also highlight the need to formulate better regulation strategies for the safe use of antimicrobials on food-producing farms.

Adult↗
PubMed2005

Production of beta-galactosidase by Bifidobacteria as influenced by various culture conditions.

Beta-Galactosidase production by Bifidobacterium longum CCRC 15708, Bifidobacterium longum B6 and Bifidobacterium infantis CCRC 14633 was first examined with B. longum CCRC 15708 showing the highest production of beta-galactosidase and the highest specific activity. Further study with B. longum CCRC 15708 revealed that the highest level of beta-galactosidase was produced with lactose and yeast extract as carbon and nitrogen sources, respectively. Optimal enzyme production occurred at an initial pH of 6.5 and at 37 degrees C. Under these optimum culture conditions, a maximumbeta-galactosidase activity of 18.6 U/ml could be obtained after 16 h of fermentation in a medium contain 4% lactose, 3.5% yeast extract, 0.3% K2HPO4, 0.1% KH2PO4, 0.05% MgSO4.7H2O and 0.03% L-cysteine. The highest transgalactosylation activity was also detected in this culture after 14-16 h of fermentation.

Bifidobacterium↗
PubMed2004

Congener-specific polychlorinated biphenyls in cetaceans from Taiwan waters.

During 2000 to 2001, a total of 73 blubber samples from 13 species of stranded or accidentally captured cetaceans were collected from Taiwan coastal waters for polychlorinated biphenyl (PCB) analysis. After homogenization, saponification, liquid-liquid extraction, and silica-gel solid-phase extraction, PCB concentrations were determined by gas chromatography/mass spectrometry. Total concentrations of 19 PCB congeners (SigmaPCBs) were between 0.23 microg/g lipid weight of Risso's dolphin to 33.73 microg/g lipid weight of rough-toothed dolphin. Pentachlorobiphenyls, hexachlorobiphenyls and heptachlorobiphenyls were the predominant PCB congeners species. PCB153 was the most abundant congener in all samples. The PCB153/SigmaPCBs consistently comprised between 20% to 30% of all congeners. The toxicity measured as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) were from 2.7 pg/g lipid weight of finless porpoise to 2,900 pg/g lipid weight of rough-toothed dolphin. PCB 118, a mono-ortho congener, was the largest contributor to TEQs. PCB concentrations and TEQs were higher in mature male than in immature male animals but were inconsistent in female animals because of a possible transferring of PCBs from maternal cetaceans to their offsprings during gestation and lactation. Stranded cetaceans had significantly higher PCB levels than by-catch cetaceans because of their higher lipid consumption during starvation or illness. From the collected samples, we also found that cetaceans from Taiwan waters had relatively lower PCB concentrations and TEQs than those from high-latitude areas.

Animals↗
PubMed2004

Risk factors for cumulative mortality in broiler chicken flocks in the first week of life in Taiwan.

(1) Factors influencing the survival of chickens in the first week of life in Taiwan were identified by modelling data from 63% of the annual national broiler production database (4769 broiler flocks). (2) Broiler chicks raised in rooms with open-curtain ventilation had the lowest mean first week cumulative mortality (CM), 1.30%, relative to those raised in rooms with negative pressure ventilation (1.42%) and water-cooled ventilation (1.37%). Increasing flock size reduced the CM. Broiler chicks shipped distances within 50 km had the lowest CM (1.22%), while broiler chicks raised in mountain areas showed the highest CM (1.65%). (3) Multiple regression analysis results indicate that ventilation type, flock size, shipping distance and delivery route influence CM in broiler chickens. Broiler chicks kept in rooms with negative pressure ventilation have an 11.22% greater CM compared to those in rooms with open-curtain ventilation. For each 1000-chicken increase in flock size, CM is reduced by 0.12%. For each kilometre increase in shipping distance, CM increases by 0.05%. Broiler chicks delivered via mountain routes show a 9.48% increase in CM compared to delivery via flat terrain. (4) Negative pressure ventilation and delivery via mountain routes are the most critical factors affecting the survival of chicks up to one week old.

Age Factors↗
PubMed2003

The cytotoxicity of jet fuel aromatic hydrocarbons and dose-related interleukin-8 release from human epidermal keratinocytes.

Many jet fuel aromatic hydrocarbons are known carcinogens with the ability to both readily penetrate the skin with high absorptive flux and cause skin irritation. In order to evaluate the in vitro cutaneous toxicity of individual aromatic hydrocarbons in jet fuels and their potential for inducing skin irritation, we evaluated the LD(50), the highest non-cytotoxic (5% mortality) dose (HNTD), and interleukin-8 (IL-8) release activity of nine major jet fuel aromatic hydrocarbons in human epidermal keratinocytes (HEK). LD(50) ranged from 1.8 mM (0.03%) for cyclohexylbenzene to 82.9 mM (0.74%) for benzene, with a rank order potency of cyclohexylbenzene >trimethylbenzene >/=xylene >dimethylnaphthalene >ethylbenzene >toluene >benzene. The HNTD values ranged from 0.1 mM (0.001%) for cyclohexylbenzene to 48.2 mM (0.43%) for benzene. Naphthalene and methylnaphthalene could not be ranked in this comparison since their concentrations, presented as percentage saturation, were not comparable to the others presented as solutes in solution. There was a dose-related differential response in IL-8 release at 24 h. Toluene, xylene, trimethylbenzene, cyclohexylbenzene and dimethylnaphthalene significantly decreased IL-8 release at the respective HNTDs, while IL-8 release did not continue to decrease, or significantly increased (cyclohexylbenzene and dimethylnaphthalene), at the LD(50). IL-8 significantly increased with both doses of methylnaphthalene and naphthalene. The presence of hexadecane and mineral oil greatly attenuated the cytotoxicity elicited by individual aromatic hydrocarbons in HEK cells.

Aircraft↗
PubMed2003

Pharmacological evaluation of several major ingredients of Chinese herbal medicines in human hepatoma Hep3B cells.

Long-dan-tan (Chinese name) is one of the most common herbal medicines used by Chinese people with chronic liver disease. Accumulated anecdotal evidence suggests that Long-dan-tan may show a beneficial effect in patients with hepatocellular carcinoma. Long-dan-tan is made from five plants: Gentiana root, Scutellaria root, Gardenia fruit, Alisma rhizome, and Bupleurum root. In this study, we have examined the cytotoxic effects of the five major ingredients isolated from the above plants, i.e. gentiopicroside, baicalein, geniposide, alisol B acetate and saikosaponin-d, respectively, on human hepatoma Hep3B cells. Annexin V immunofluorescence detection, DNA fragmentation assays and FACScan analysis of propidium iodide-staining cells showed that gentiopicroside, baicalein, and geniposide had little effect, whereas alisol B acetate and saikosaponin-d profoundly induced apoptosis in Hep3B cells. Alisol B acetate, but not saikosaponin-d, induced G2/M arrest of the cell cycle as well as a significant increase in caspase-3 activity. Interestingly, baicalein by itself induced an increase in H(2)O(2) generation and the subsequent NF-kappaB activation; furthermore, it effectively inhibited the transforming growth factor-beta(1) (TGF-beta(1))-induced caspase-3 activation and cell apoptosis. We suggest that alisol B acetate and saikosaponin-d induced cell apoptosis through the caspase-3-dependent and -independent pathways, respectively. Instead of inducing apoptosis, baicalein inhibits TGF-beta(1)-induced apoptosis via increase in cellular H(2)O(2) formation and NF-kappaB activation in human hepatoma Hep3B cells.

Annexin A5↗
PubMed2002

Potential application of gas chromatography/tandem mass spectrometry in the measurement of coeluting isomers.

Despite the unprecedented popularity of separation chromatography, the measurement of coeluting isomeric chemicals remains an extremely difficult task. We developed an analytical scheme capable of measuring two coeluting isomers using a single chromatographic column and a gas chromatography/tandem mass spectrometry system. The protocol utilized two product ion fragments generated from a common parent ion associated with the isomers for quantitation. The utility of the analytical scheme was demonstrated with the measurements of several pairs of coeluting polychlorinated biphenyl (PCB) isomers in standard solutions and fish liver samples. Best results were given when a set of stringent constraints for the abundance ratio of the two product ion fragments was satisfied. Analyses of seven fish liver samples collected from nearshore San Diego, CA, indicated that the domain that had been previously reported to comprise PCB 153 and PCB 168 actually contained PCB 153 only. Although only a selected number of PCB congeners were examined, the results presented indicate that the analytical scheme has the potential to be used to determine the concentrations of all chromatographically coeluted isomers.

Journal Article↗
PubMed2001

Crystallization and preliminary X-ray diffraction analysis of the 10 kDa C-terminal subdomain of 70 kDa heat-shock cognate protein.

The 70 kDa heat-shock cognate protein (Hsc70) is a cytosolic molecular chaperone. It is composed of a 44 kDa N-terminal nucleotide-binding domain, an 18 kDa peptide-binding subdomain and a 10 kDa C-terminal subdomain. Single crystals of recombinant 10 kDa subdomain of rat Hsc70 have been obtained using ammonium sulfate as a precipitant at room temperature. The crystals diffract beyond 3.5 A using a synchrotron-radiation source at a wavelength of 1.0 A. The crystals belong to the hexagonal space group P6(1)22 or P6(5)22, with unit-cell parameters a = b = 119.0, c = 166.4 A.

Animals↗
PubMed2001

Phase I/II trial evaluating combined radiotherapy and in situ gene therapy with or without hormonal therapy in the treatment of prostate cancer--a preliminary report.

PURPOSE: To report the preliminary results of a Phase I/II study combining radiotherapy and in situ gene therapy (adenovirus/herpes simplex virus thymidine kinase gene/valacyclovir) with or without hormonal therapy in the treatment of prostate cancer. METHODS AND MATERIALS: Arm A: low-risk patients (T1-T2a, Gleason score <7, pretreatment PSA <10) were treated with combined radio-gene therapy. A mean dose of 76 Gy was delivered to the prostate with intensity-modulated radiotherapy. Arm B: high-risk patients (T2b-T3, Gleason score >or=7, pretreatment PSA >or=10) were treated with combined radio-gene therapy and hormonal therapy. Hormonal therapy was comprised of a 4-month leuprolide injection and 2-week use of flutamide. Arm C: Stage D1 (positive pelvic lymph node) patients received the same regimen as Arm B, with the additional 45 Gy to the pelvic lymphatics. Treatment-related toxicity was assessed using Cancer Therapy Evaluation Program common toxicity score and Radiation Therapy Oncology Group (RTOG) toxicity score. RESULTS: Thirty patients (13 in Arm A, 14 in Arm B, and 3 in Arm C) completed the trial. Median follow-up was 5.5 months. Eleven patients (37%) developed flu-like symptoms (Cancer Therapy Evaluation Program Grade 1) of fatigue and chills/rigors after gene therapy injection but recovered within 24 h. Four patients (13%) and 2 patients (7%) developed Grade 1 and 2 fever, respectively. There was no patient with weight loss. One patient in Arm B developed Grade 3 elevation in liver enzyme, whereas 11 and 2 patients developed Grade 1 and 2 abnormal liver function tests. There was no Grade 2 or above hematologic toxicity. Three patients had transient rise in creatinine. There was no RTOG Grade 3 or above lower gastrointestinal toxicity. Toxicity levels were as follows: 4 patients (13%), Grade 2; 6 patients (20%), Grade 1; and 20 patients (67%), no toxicity. There was 1 patient with RTOG Grade 3 genitourinary toxicity, 12 patients (40%) with Grade 2, 8 patients (27%) with Grade 1, and 9 patients (30%) with no toxicity. No patient dropped out from the trial or had to withhold treatment because of severe toxicity. CONCLUSIONS: This is the first trial of its kind in the field of prostate cancer that aims to expand the therapeutic index of radiotherapy by combining in situ gene therapy. Initial experience has demonstrated the safety of this approach. There is no added toxicity to each therapy used alone. Long-term follow-up and larger cohort studies are warranted to evaluate long-term toxicity and efficacy.

Adenoviridae↗
PubMed2001

Acid adaptation and temperature effect on the survival of E. coli O157:H7 in acidic fruit juice and lactic fermented milk product.

In this study, two strains of Escherichia coli O157:H7, (ATCC 43889 and ATCC 43895) were acid adapted at pH 5.0 in tryptic soy broth (TSB) for 4 h. Commercial products of mango juice (pH 3.2), asparagus juice (pH 3.6), Yakult--a diluted milk fermented drink (pH 3.6), and low-fat yoghurt (pH 3.9) were inoculated with acid-adapted or nonadapted cells of E. coli O157:H7. Survival of the inoculated E. coli O157:H7 in these commercial food products during storage at 25 or 7 degrees C was examined. It was found that although survival of the acid-adapted and nonadapted E. coli O157:H7 ATCC 43895 in asparagus juice during storage at 7 degrees C did not show marked difference, in general, acid adaptation and low temperature enhanced the survival of E. coli O157:H7 in both the commercial fruit juices tested. On the contrary, acid adaptation reduced the survival of both the strains of the test organism in Yakult and low-fat yoghurt stored at 7 degrees C. Besides, E. coli O157:H7 ATCC 43895 survived longer than ATCC 43889 in all the products examined, regardless of the storage temperature and acid adaptation.

Adaptation, Physiological↗
PubMed2001

SCH-C (SCH 351125), an orally bioavailable, small molecule antagonist of the chemokine receptor CCR5, is a potent inhibitor of HIV-1 infection in vitro and in vivo.

We describe here the identification and properties of SCH-C (SCH 351125), a small molecule inhibitor of HIV-1 entry via the CCR5 coreceptor. SCH-C, an oxime-piperidine compound, is a specific CCR5 antagonist as determined in multiple receptor binding and signal transduction assays. This compound specifically inhibits HIV-1 infection mediated by CCR5 in U-87 astroglioma cells but has no effect on infection of CXCR4-expressing cells. SCH-C has broad and potent antiviral activity in vitro against primary HIV-1 isolates that use CCR5 as their entry coreceptor, with mean 50% inhibitory concentrations ranging between 0.4 and 9 nM. Moreover, SCH-C strongly inhibits the replication of an R5-using HIV-1 isolate in SCID-hu Thy/Liv mice. SCH-C has a favorable pharmacokinetic profile in rodents and primates with an oral bioavailability of 50-60% and a serum half-life of 5-6 h. On the basis of its novel mechanism of action, potent antiviral activity, and in vivo pharmacokinetic profile, SCH-C is a promising new candidate for therapeutic intervention of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Human B cell-attracting chemokine 1 (BCA-1; CXCL13) is an agonist for the human CXCR3 receptor.

The CXC chemokine CXCL13, known as BCA-1 (B cell-attracting chemokine 1) or BLC (B-lymphocyte chemoattractant), has been identified as an efficacious attractant selective for B lymphocytes. The chemokine receptor BLR1 (Burkitt's lymphoma receptor 1)/CXCR5 expressed by all mature B cells has to date been identified as the only known receptor for BCA-1. As the loss of the BLR1/CXCR5 receptor is sufficient to disrupt organization of follicles in spleen and Peyer's patches, BCA-1 may act as a B cell homing chemokine. Nonetheless, BCA-1 has not been tested against all known chemokine receptors. In this study, we report that human BCA-1 competes with radiolabeled interferon gamma (IFN-gamma) inducible protein 10 (IP-10) for binding to the human CXCR3 receptor expressed in Ba/F3 and 293EBNA cell lines. Furthermore, human BCA-1 is an efficacious attractant for human CXCR3 transfected cells; BCA-1-induced chemotaxis is inhibited by a monoclonal antibody against human CXCR3. In these cells, as in human B lymphocytes expressing CXCR5, BCA-1 does not induce a calcium flux. Indeed, BCA-1 attenuates the calcium flux induced by IP-10. In addition, human BCA-1 is an agonist in stimulating GTP gamma S binding. Together these data suggest that human BCA-1 is a specific and functional G-protein-linked chemotactic ligand for the human CXCR3 receptor. The biological significance of this new finding is supported by our recent observation that human BCA-1 induces chemotaxis of activated T cells and the BCA-1-induced chemotaxis is inhibited by a monoclonal antibody against human CXCR3.

Animals↗
PubMed2001

Effects of carbon and nitrogen sources, sodium chloride and culture conditions on cytotoxin production by Salmonella choleraesuis.

The effects of carbon and nitrogen sources, incubation temperature, shaking speed, initial pH of culture broth as well as various concentration of NaCl on the production of cytotoxin by Salmonella choleraesuis SC-5 were evaluated in the present study. Results reveal that the optimal temperature, initial medium pH and shaking speed for cytotoxin production was 37 degrees C, pH 6.0-8.0 and 100 rpm, respectively. Tryptone was the best of the eight nitrogen sources tested for toxin production by S. choleraesuis. Among the nine carbon sources tested, S. choleraesuis produced a higher amount of cytotoxin in media containing glucose, fructose, galactose, sorbitol or mannitol as the carbon source. No toxin was detected in broths containing 4.0% or more sodium chloride in Tryptic soy broth (TSB). Cultures of S. choleraesuis in the medium containing 2.0% tryptone, 0.5% NaCl, 0.25% K2HPO4 and 0.25% of the best carbon source under the optimal conditions for 14 h resulted in the highest cytotoxin production. The Vero cell CD50 of S. choleraesuis lysate of cells grown under these optimal conditions was a titer of 589-758 per mg of lysate protein.

Carbon↗
PubMed2001

Surface characteristics of Bacillus cereus and its adhesion to stainless steel.

The ability of a Bacillus cereus strain, isolated from spoiled milk, to adhere to the surface of stainless steel chips was evaluated during its growth in diluted tryptic soy broth (DTSB). The number of cells that adhered to the surface increased markedly as the culture reached the end of the log phase and entered stationary phase, and continued to increase with further incubation. The surface properties of cells from the log, stationary, and late stationary phases were measured by hydrophobic interaction chromatography (HIC) and electrostatic interaction chromatography (ESIC). It was found that surface hydrophobicity of B. cereus vegetative cells from the late stationary phase was the highest followed by those from the stationary phase and the log phase cultures. While the vegetative cells prepared from stationary phase and log phase cultures, respectively, had the highest and the lowest surface charges. Adhesion of B. cereus vegetative cells to stainless steel was positively correlated with the cell surface hydrophobicity (R = 0.979). Surface hydrophobicity and surface positive charge noted on the spores harvested from diluted tryptic soy agar (DTSA) and Mn2+-tryptone glucose extract agar were higher than those harvested from the sucrose or lactose-added DTSA. A wide variation in the surface charge values was noted on the surface of various spores prepared from cultures grown on the four different media tested, while their ability to adhere to stainless steel chips in phosphate buffered saline (PBS) showed no significant difference (p > 0.05). Similarly, the number of spores or vegetative cells adhering to stainless steel suspended in PBS, milk or diluted milk (1000 x) did not differ significantly (p > 0.05).

Agar↗
PubMed2001

The crystal structure of a novel mammalian lectin, Ym1, suggests a saccharide binding site.

Ym1, a secretory protein synthesized by activated murine peritoneal macrophages, is a novel mammalian lectin with a binding specificity to GlcN. Lectins are responsible for carbohydrate recognition and for mediating cell-cell and cell-extracellular matrix interactions in microbes, plants, and animals. Glycosaminoglycan heparin/heparan sulfate binding ability was also detected in Ym1. We report here the three-dimensional structure of Ym1 at 2.5-A resolution by x-ray crystallography. The crystal structure of Ym1 consists of two globular domains, a beta/alpha triose-phosphate isomerase barrel domain and a small alpha + beta folding domain. A notable electron density of sugar is detected in the Ym1 crystal structure. The saccharide is located inside the triose-phosphate isomerase domain at the COOH terminal end of the beta-strands. Both hydrophilic and hydrophobic interactions are noted in the sugar-binding site in Ym1. Despite the fact that Ym1 is not a chitinase, structurally, Ym1 shares significant homology with chitinase A of Serratia marcescens. Ym1 and chitinase A have a similar carbohydrate binding cleft. This study provides new structure information, which will lead to better understanding of the biological significance of Ym1 and its putative gene members.

Amino Acid Sequence↗
PubMed2001

Influence of holding temperature on the growth and survival of Salmonella spp. and Staphylococcus aureus and the production of staphylococcal enterotoxin in egg products.

In this study, growth and survival of Salmonella spp. and Staphylococcus aureus in steamed egg and scrambled egg held at 5, 18, 22, 37, 55 and 60 degrees C are investigated. The production of staphylococcal enterotoxin in steamed egg is also examined. Results reveal that Salmonella spp. and Staph. aureus in the egg products multiply best at 37 degrees C, followed closely by 22 and 18 degrees C. Neither pathogen showed growth in the egg products held at 5 degrees C. Initial inoculation dose, holding temperature and holding time affected the population of both organisms found in the egg products. Staphylococcal enterotoxin A (SEA) and B (SEB) are detected only in the egg products held at 37 or 22 degrees C. After holding at 37 degrees C for 36 h, scrambled egg inoculated with ca. 5.0 log cfu/g Staph. aureus contains the highest levels of SEA (> 64 ng/g) and SEB (> 64 ng/g). Although Salmonella spp. and Staph. aureus grow better in steamed eggs than in scrambled eggs, production of staphylococcal enterotoxin, in general, was higher in scrambled eggs than in steamed eggs. On the other hand, a repaid destruction of the test organisms in steamed eggs held at 60 degrees C was observed. Holding the steamed eggs at 60 degrees C, Salmonella spp. and Staph. aureus with an initial population of ca. 5.9 and 5.6 log cfu/g, respectively, reduced to a non-detectable level in 1 h.

Colony Count, Microbial↗
PubMed2001

Continuous measurement of caffeine and two metabolites in blood and skeletal muscle of unrestrained adult horses by semi-automated in vivo microdialysis.

Concentrations of caffeine (CA) and two metabolites were measured simultaneously in venous blood and splenius muscle of adult horses using a semi-automated in vivo microdialysis sampling technique. Dialysates from muscle and jugular vein were collected continuously for 48 h and drug levels were determined by high performance liquid chromatography (HPLC). Following i.v. injection, CA (3 mg/kg) attained a peak blood level of nearly 5400 +/- 600 ng/mL and decreased with a half-life of 15.3 +/- 0.7 h. Pharmacokinetic and statistical comparisons between CA concentrations in jugular dialysates and plasma samples revealed no significant differences between these sampling techniques. However, measurements in muscle and blood revealed unexpected pharmacokinetic differences, including significantly elevated concentrations of CA in muscle for 4 h following drug administration. In contrast, the CA metabolites theophylline (TP) and theobromine (TB) exhibited delayed appearances in muscle and blood with peak concentrations of 300 +/- 60 ng/mL (TP) and 150 +/- 50 ng/mL (TB) detected in both tissues 1 day following CA administration. This study demonstrates that our novel semi-automated microdialysis procedure for continuous monitoring of drug and metabolite levels may be useful for related studies in other domesticated large animal species.

Animals↗