Biomedical subjects

C Huang

Publications and source records attributed to C Huang.

At least 91 records · Page 5Linked to original sources

PubMed2001

The expression of Fas/FasL in peripheral blood lymphocytes and the level of IL-2 in serum of patients with condyloma acuminata.

In order to investigate the role of the expression of the Fas/FasL in peripheral blood lymphocytes (PBLC) and the level of IL-2 in serum of patients with condyloma acuminata (CA) in the immune pathogenesis of CA, flow cytometry, indirect immunofluorescence labeling and ELISA were performed to detect the expression of the apoptotic regulatory proteins Fas/FasL in PBLC and the level of IL-2 in serum of 60 patients with different course of CA. The results showed that the expression of Fas/FasL in PBLC of the group of short course in CA was significantly higher than that of the normal controls (P < 0.05); the expression of Fas, FasL in PBLC of the group of long course CA was significantly higher than that of the group of short course and the normal controls (P < 0.05 and P < 0.01, respectively); the level of IL-2 in serum of the group of short and long course CA was significantly lower than that of the group of normal controls (P < 0.01); the negative relation was revealed between the expression of Fas/FasL in PBLC and the level of IL-2 in serum of patients with CA (r = -0.76, P < 0.01). It was suggested that the abnormal apoptosis in PBLC and decreased level of IL-2 in serum of CA might play an important role in the course of CA.

Adolescent↗

PubMed2001

Analysis for Giardia cysts and Cryptosporidium oocysts in water samples from small water systems in Taiwan.

Giardia and Cryptosporidium have emerged as waterborne pathogens of concern. Twenty-six water samples were collected from small water systems in Taiwan and checked for the occurrence of both parasites. Water quality parameters and characteristics of the sampling sites were also recorded. The frequencies of occurrence for Giardia and Cryptosporidium were 46.2% for each; and their mean concentrations were 79.5 cysts/100 l and 22.1 oocysts/100 l, respectively. The concentrations of oocysts and heterotrophic bacteria exhibited the highest correlation and followed the concentrations of the two protozoa. The water samples from sites with filtration devices had a lower oocyst concentration than those from sites without filtration devices, while no significant difference was found for cysts. The level of each parasite had no direct relationship with altitude. The cyst concentrations increased proportionally with the consumer population using the water systems. Risk assessment of the parasitic infections suggests that setting up disinfection devices in the small water systems would be needed.

Animals↗

PubMed2001

Evaluation of immunomagnetic separation method for detection of Giardia for different reaction times and reaction volumes.

Immunomagnetic separation (IMS) has been specified as a standard method for the measurement of Giardia. In this study, Dynal IMS was evaluated on the basis of recovery efficiencies of Giardia cysts for various IMS operational conditions. The average recoveries for Giardia in deionized, treated and raw water samples were 82.6 +/- 12.2% (n = 6), 75.6 +/- 15.2% (n = 3), and 70.6 +/- 18.2% (n = 3), respectively. Significant changes in recovery were observed by altering the debris ratio and the debris components of water samples. Changing the reaction volume within the same vessel had no significant effect on cyst recovery efficiencies. However, prolonging the reaction time did increase recovery efficiencies.

Animals↗

PubMed2001

E-cadherin expression associated with differentiation and prognosis in patients with non-small cell lung cancer.

BACKGROUND: E-Cadherin plays a major role in maintaining the intercellular junctions in epithelial tissues. The reduction of E-cadherin expression in cancer cells may be associated with tumor differentiation, metastasis, and a poor prognosis. METHODS: Immunohistochemistry for E-cadherin expression was performed on 109 tumors from patients with non-small cell lung cancer who underwent operations. RESULTS: With respect to membranous immunostaining, 57 carcinomas were E-cadherin-positive, 39 carcinomas E-cadherin-reduced, and 13 carcinomas E-cadherin-negative. The percentage of poorly differentiated tumors in the impaired E-cadherin expression group was significantly higher than that in the E-cadherin-positive group (p = 0.005). Furthermore, the frequency of lymph node metastases in tumors with impaired E-cadherin expression was significantly higher than that in the E-cadherin-positive tumors (p = 0.011). A Cox regression analysis revealed that E-cadherin expression was a significant factor in the prediction of survival for patients with non-small cell lung cancer (p = 0.002). CONCLUSIONS: E-Cadherin expression was associated with tumor differentiation, lymph node metastasis, and prognosis in patients with non-small cell lung cancer.

Cadherins↗

PubMed2001

Evaluation of two concentration methods for detecting Giardia and Cryptosporidium in water.

The cartridge filtration method and membrane filtration method based on the fluorescent antibody procedure were evaluated for their recovery efficiencies and detection limits of Giardia and Cryptosporidium. We assessed the performances of the two concentration methods for water samples collected from Taiwan water treatment plants. The membrane filtration method was characterized by higher recovery rate and detection limit comparing with the cartridge filtration method. The occurrences of both parasites, and the relationships of parasite concentrations with indicator microorganisms show inconsistency between the two methods. It was discovered that water turbidity reduced the recovery efficiencies, and raised the detection limits for both parasites regardless of the method used.

Animals↗

PubMed2001

Filtration behaviors of Giardia and Cryptosporidium--ionic strength and pH effects.

The laboratory-scale filtration tests of Giardia cysts and Cryptosporidium oocysts in both 2 mm-phi glass beads and 2 mm-phi polystyrene beads filters were conducted to investigate their filtration behaviors. The protozoan parasites were used as target particles, while the chemical system altered by changing the electrolyte concentration and pH. The results significantly indicate that ionic strength have a positive effect on the removal efficiencies for Giardia cysts and Cryptosporidium oocysts. The removal efficiency of two filters for Giardia cysts slightly decreased from pH 2.4 to 8.7 and decreased significantly in pH as pH up to 8.7, while that for Cryptosporidium slightly rippled beyond pH 8.7, and with the decrease in pH up to pH 8.7. The experimental collision efficiencies from the interactions between colloids and the filter media were calculated with a semi-empirical approach of the single sphere model and clean-bed filtration theory. The results also indicated that experimental collision efficiencies for (oo)cysts corresponded to the (oo)cysts removal efficiencies in all trials, and oocysts exhibits higher collision efficiencies than cysts.

Animals↗

PubMed2001

Biological elimination of H2S and NH3 from wastegases by biofilter packed with immobilized heterotrophic bacteria.

Biotreatment of various ratios of H2S and NH3 gas mixtures was studied using the biofilters, packed with co-immobilized cells (Arthrobacter oxydans CH8 for NH3 and Pseudomonas putida CH11 for H2S). Extensive tests to determine removal characteristics, removal efficiency, removal kinetics, and pressure drops of the biofilters were performed. To estimate the largest allowable inlet concentration, a prediction model was also employed. Greater than 95%, and 90% removal efficiencies were observed for NH3 and H2S, respectively, irrespective of the ratios of H2S and NH3 gas mixtures. The results showed that H2S removal of the biofilter was significantly affected by high inlet concentrations of H2S and NH3. As high H2S concentration was an inhibitory substrate for the growth of heterotrophic sulfur-oxidizing bacteria, the activity of H2S oxidation was thus inhibited. In the case of high NH3 concentration, the poor H2S removal efficiency might be attributed to the acidification of the biofilter. The phenomenon was caused by acidic metabolite accumulation of NH3. Through kinetic analysis, the presence of NH3 did not hinder the NH3 removal, but a high H2S concentration would result in low removal efficiency. Conversely, H2S of adequate concentrations would favor the removal of incoming NH3. The results also indicated that maximum inlet concentrations (model-estimated) agreed well with the experimental values for space velocities of 50-150 h(-1). Hence, the results would be used as the guideline for the design and operation of biofilters.

Air Pollution↗

PubMed2001

Myocyte apoptosis in the pathogenesis of ureteral damage in rats with obstructive uropathy.

OBJECTIVES: To elucidate the role of signal apoptosis in the pathogenesis of ureteral damage during the course of obstructive uropathy and to investigate the cell proliferation in the smooth muscle layer of ligated ureter. METHODS: The apoptotic cells were detected with the method of in situ end-labeling of DNA fragments. The expression of Fas, tumor necrosis factor receptor 1 (TNF-R1), and proliferation cell nuclear antigen (PCNA) was examined in 54 rats by immunohistochemistry. RESULTS: The severity of hydroureter and the histologic changes of ureteral smooth muscle were aggravated during the period of obstruction. The apoptotic cells and the expression of Fas and PCNA in the smooth muscle layer were present since day 14 after ligation. The percentages of apoptotic cells and the expression indexes of Fas and PCNA in the smooth muscle layer progressively increased, reaching a peak on day 21 after ligation, and then declined. The expression of TNF-R1 in the smooth muscle layer was only found on day 21 after ligation. The numbers of the apoptotic cells in the smooth muscle layer correlated significantly with the expression of PCNA, Fas, and TNF-R1. The expression of Fas and TNF-R1 in the smooth muscle layer also correlated significantly. The appearance of apoptotic cells and the expression of Fas and PCNA in the smooth muscle layer were associated with tissue damage and fibrosis in the smooth muscle layer. CONCLUSIONS: We conclude that cell apoptosis and the expression of Fas, TNF-R1, and PCNA might play important roles in the pathogenesis of ureteral damage in the smooth muscle layer of obstructed ureters.

Animals↗

PubMed2001

Cloning and developmental expression of Xenopus Stat1.

Proteins of the STAT family (Signal Transducers and Activators of Transcription) are latent cytoplasmic factors which, upon phosphorylation, are translocated to the nucleus where they participate in gene activation. In this report, we describe the cloning and developmental expression of a Xenopus homolog of Stat1. XStat1 is highly conserved, exhibiting greater than 90% identity in the critical DNA binding, SH2, SH3 and trans-activation domains with both human and murine Stat1. Using RT-PCR, we show that XStat1 is present as a maternal message during early development of Xenopus. The maternal message is translated during cleavage and its product is phosphorylated on tyrosine, a prerequisite for functional activation. During cleavage and gastrula stages, XStat1 is widely expressed throughout the developing embryo. During neurulation and early tailbud stages, XStat1 is expressed in both dorsal axial and ventral tissues. By late tailbud, dorsal XStat1 expression domains are associated with the developing pharyngeal arches and pronephros. These regions of the embryo correspond to the future location of the thymus, sites of dorsal hematopoietic activity, and one location where melanocytes differentiate.

Amino Acid Sequence↗

PubMed2001

Detection of arboviral RNA directly from mosquito homogenates by reverse-transcription-polymerase chain reaction.

Many arthropod-borne viruses (arboviruses) are important human pathogens medically. The development of an effective technique to detect the viruses by using nucleic acid amplification, such as polymerase chain reaction (PCR), improves not only clinical diagnosis but also virologic surveillance of mosquito vectors in the field. In this study, the development of an improved and simplified assay is described for detection of mosquitoes infected with eastern equine encephalitis (EEE) virus, Cache Valley (CV), and California (CAL) serogroup viruses from field-collected mosquito pools. As little as 5 microl of homogenate from mosquito pools was used in the reverse transcription (RT) reaction followed by the use of three sets of specific primers for the PCR. Positive pools were determined by finding PCR bands of the expected size for each arbovirus. The confirmation and identification of Bunyaviruses was done by sequencing the PCR product. In 1999, West Nile virus (WNV) was identified as the etiologic agent of an outbreak of human encephalitis in New York City. It is shown that this protocol is also able to detect West Nile viral RNA in a pool of 100 mosquitoes containing one infected mosquito.

Aedes↗

PubMed2001

Purification and characterization of White Spot syndrome virus (WSSV) produced in an alternate host: crayfish, Cambarus clarkii.

Penaeid shrimp is the natural host of White Spot Syndrome Virus (WSSV) that can cause high mortality in the infected hosts. Attempts to obtain sufficient amounts of purified intact WSSV for characterization have been unsuccessful. Using crayfish, Cambarus clarkii as a proliferation system, a large amount of infectious WSSV was reproduced and intact WSSV viral particles were purified with a new isolation medium by ultra-centrifugation. Purified WSSV particles were very sensitive to organic solvents and the detergent, Triton X-100. The size of the rod-shape, somewhat elliptical, intact WSSV was 110-130x260-350 nm with a long, tail-like envelope extension. The naked viral nucleocapsid was about 80x350 nm, and it possessed 15 spiral and cylindrical helices composed of 14 globular capsomers along its long axis, and a 'ring' structure at one terminus. Distinct WSSV genome DNA patterns were obtained when the purified genomic dsDNA of WSSV was digested with five different restriction enzymes (HindIII, XhoI, BamHI, SalI, and SacI). In addition, at least 13 major and distinct protein bands could be observed when purified intact WSSV viruses were separated by SDS-PAGE followed by Coomassie Brilliant R-250 staining. The estimated molecular weights of these proteins were 190, 84, 75, 69, 68, 58, 52, 44, 28, 27.5, 23, 19, and 16 kD, respectively. Both the 44 and 190 kD proteins were easily removed if the hemolymph from the WSSV infected crayfish was transiently treated with 1% Triton X-100 before it was subjected to gradient centrifugation, indicating that both of them are located on the surface of the viral envelope. These characteristics are consistent with WSSV isolated from the penaeid shrimp.

Animals↗

PubMed2001

Cold adaptive thermogenesis in small mammals from different geographical zones of China.

The mechanisms of thermogenesis and thermoregulation were studied in the tree shrew (Tupaia belangeri) and greater vole (Eothenomys miletus) of the subtropical region, and Brandt's vole (Microtus brandti), Mongolian gerbil (Meriones unguiculatus), Daurian ground squirrel (Spermophilus dauricus) and plateau pika (Ochotona curzoniae) of the northern temperate zone. Resting metabolic rate (RMR) and non-shivering thermogenesis (NST) increased significantly in T. belangeri, E. miletus, M. brandti and M. unguiculatus after cold acclimation (4 degrees C) for 4 weeks. In T. belangeri, the increase in RMR and thermogenesis at liver cellular level were responsible for enhancing the capacity of enduring cold stress, and homeothermia was simultaneously extended. Stable body temperature in M. brandti, E. miletus, M. unguiculatus and O. curzoniae was maintained mainly through increase in NST, brown adipose tissue (BAT) mass and its mitochondrial protein content, and the upregulation of uncoupling protein (UCP1) mRNA, as well as enhancement of the activity of cytochrome C oxidase, alpha-glycerophosphate oxidase and T(4) 5'-deiodinase in BAT mitochondria. The RMR in O. curzoniae and euthermic S. dauricus was not changed, while NST significantly increased during cold exposure; the former maintained their stable body temperature and mass, while body temperature in the latter declined by 4.8 degrees C. The serum T(3) concentration or ratio of T(3)/T(4) in all the species was enhanced after cold acclimation. Results indicated that: (1) the adaptive mechanisms of T. belangeri residing in the subtropical region to cold are primarily by increasing RMR and secondly by increasing NST, and the mechanisms of thermogenesis are similar to those in tropical mammals; (2) in small mammals residing in northern regions, the adaptation to cold is chiefly to increase NST; (3) the mechanism of cold-induced thermogenesis in E. miletus residing in subtropical and high mountain regions is similar to that in the north; (4) a low RMR in warm environments and peak RMR and NST in cold environments enabled M. unguiculatus to tolerate a semi-desert climate; (5) O. curzoniae has unusually high RMR and high NST, acting mainly via increasing NST to adapt to extreme cold of the Qinghai-Tibet Plateau; (6) the adaptation of euthermic S. dauricus to cold is due to an increase in NST and a relaxed homeothermia; and lastly (7) the thyroid hormone is involved in the regulation of cold adaptive thermogenesis in all the species studied.

Adaptation, Physiological↗

PubMed2001

The solution structure of [d(CGC)r(amamam)d(TTTGCG)]2.

The solution structure and hydration of a DNA.RNA hybrid chimeric duplex [d(CGC)r(amamam)d(TTTGCG)]2 in which the RNA adenines were substituted by 2'-O-methylated riboadenines was determined using two-dimensional NMR, simulated annealing, and restrained molecular dynamics. Only DNA residue 7T in the 2'-OMe-RNA.DNA junction adopted an O4'-endo sugar conformation, while the other DNA residues including 3C in the DNA.2'-OMe-RNA junction, adopted C1'-exo or C2'-endo conformations. The observed NOE intensity of 2'-O-methyl group to H1' proton of 4am at the DNA.2'-OMe-RNA junction is much weaker than those of 5am and 6am. The 2'-O-methyl group of 4am was found to orient towards the minor groove in the trans domain while the 2'-O-methyl groups of 5am and 6am were found to be in the gauche (+) domain. In contrast to the long-lived water molecules found close to the RNA adenine H2 and H1' protons and the methyl group of 7T in the RNA-DNA junction of [d(CGC)r(aaa)d(TTTGCG)]2, there were no long-lived water molecules found in [d(CGC)r(amamam)d(TTTGCG)]2. This is probably due to the hydrophobic enviroment created by the 2'-O-methylated riboadenines in the minor groove or due to the wider minor groove width in the middle of the structure. In addition, the 2'-O-methylation of riboadenines in pure chimeric duplex increses its melting temperature from 48.5 degrees C to 51.9 degrees C. The characteristic structural features and hydration patterns of this chimeric duplex provide a molecular basis for further therapeutic applications of DNA.RNA hybrid and chimeric duplexes with 2'-modified RNA residues.

Base Sequence↗

PubMed2001

Involvement of Erks activation in cadmium-induced AP-1 transactivation in vitro and in vivo.

Cadmium is a potent and effective carcinogen in rodents and has recently been accepted by IARC (International Agency for Research on Cancer) as a category I carcinogen. Cadmium-induced up-regulation of intracellular signaling pathways leading to increased mitogenesis is thought to be a major mechanism for the carcinogenic activity following chronic cadmium exposure. In the present study, we found that exposure of cells to cadmium induced significant activation of AP-1 and all three members of the MAP kinase family in mouse epidermal JB6 cells. The induction of AP-1 activity by cadmium appears to involve activation of Erks, since the induction of AP-1 activity by cadmium was blocked by pretreatment of cells with PD98058. Interestingly, the induction of AP-1 by cadmium was greatly enhanced by the chemical tumor promoter, TPA and the growth factor EGF, but not by ultraviolet C radiation. In vivo studies demonstrated that cadmium could also induce transactivation of AP-1 in AP-1-luciferase report transgenic mice. Considering the role of AP-1 activation in tumor promotion, the results presented in this study provide a possible molecular mechanism for cadmium-induced carcinogenesis.

Animals↗

PubMed2001

Appearance of Langerhans cells in the epidermis of Tgfb1(-/-) SCID mice: paracrine and autocrine effects of transforming growth factor-beta 1 and -beta 2(1).

A striking immunologic abnormality of normal and SCID Tgfb1(-/-) mice is the total absence of Langerhans cells in their epidermis. Here we show that transfer of Tgfb1(+/-) SCID bone marrow causes, within a few weeks, the appearance of Langerhans cells in the epidermis of gamma-irradiated and unirradiated Tgfb1(-/-) SCID recipients. In addition, local injection of 2 x 10(5) latent transforming growth factor-beta1 cDNA-transduced cloned CD4+ T lymphocytes causes the appearance of Langerhans cells in the ear epidermis of Tgfb1(-/-) SCID mice. This effect is enhanced by antigen-specific activation of these T cells. Injection of recombinant active transforming growth factor-beta 2 into the ear of Tgfb1(-/-) SCID mice also results in the migration of Langerhans cells into the epidermis locally, but no epidermal Langerhans cells are seen after systemic injections of transforming growth factor-beta 2. Our results suggest that transforming growth factor-beta can act in paracrine as well as autocrine fashion to induce the differentiation of precursors into Langerhans cells. Furthermore, these results indicate that the relative roles of different transforming growth factor-beta isoforms in vivo may be influenced by their local availability and/or the regulation of their conversion from latent into active form.

Animals↗

PubMed2001

Linkage and association of HLA class II genes with vitiligo in a Dutch population.

BACKGROUND: Serological typing of HLA has shown discrepancies in HLA associations with vitiligo in different ethnic populations. OBJECTIVES: To perform genotyping of HLA class II genes on a Dutch vitiligo population in order clearly to identify susceptible and protective HLA alleles in vitiligo. METHODS: HLA typing was carried out by amplifying genomic DNA by polymerase chain reaction (PCR) followed by dot-blot hybridization with sequence-specific oligonucleotides (SSO). Fifty Dutch vitiligo probands, and their parents (150 individuals) and 204 healthy controls were studied. RESULTS: Family-based case-control association studies and linkage disequilibrium analysis showed the linkage and association of DRB4*0101 allele with vitiligo (P(c) = 0.0016, relative risk = 2.21). The family-based association study also provided evidence for linkage and association of DQB1*0303 allele with vitiligo (chi(2) = 7.36, P = 0.006). We measured the clinical relevance of the test by calculating the prevalence corrected positive predictive values (PcPPV). The PcPPV of disease for the DRB4*0101 allele was 0.017 and for the DRB4*0101/0101 genotype was 0.0358. In other words, a DRB4*0101/0101 genotype carries a 3.58% risk of developing vitiligo. CONCLUSIONS: Both DRB4*0101 and DQB1*0303 alleles provide significant susceptibility for vitiligo.

Adolescent↗

PubMed2001

Hypoglycemia associated with clonidine testing for growth hormone deficiency.

We have observed 4 cases of hypoglycemia associated with clonidine stimulation of growth hormone secretion; only one patient had growth hormone deficiency. Significant drowsiness after administration of clonidine may prolong the period of fasting in these children and mask early signs and symptoms, leading to severe hypoglycemia.

Administration, Oral↗

PubMed2001

Biotreatment of hydrogen sulfide- and ammonia-containing waste gases by fluidized bed bioreactor.

Gas mixtures of H2S and NH3 are the focus of this study of research concerning gases generated from animal husbandry and treatments of anaerobic wastewater lagoons. A heterotrophic microflora (a mixture of Pseudomonas putida for H2S and Arthrobacter oxydans for NH3) was immobilized with Ca-alginate and packed into a fluidized bed reactor to simultaneously decompose H2S and NH3. This bioreactor was continuously supplied with H2S and NH3 separately or together at various ratios. The removal efficiency, removal rate, and metabolic product of the bioreactor were studied. The results showed that the efficiency remained above 95% when the inlet H2S concentration was below 30 ppm at 36 L/hr. Furthermore, the apparent maximum removal and the apparent half-saturation constant were 7.0 x 10(-8) g-S/cell/day and 76.2 ppm, respectively, in this study. The element sulfur as a main product prevented acidification of the biofilter, which maintained the stability of the operation. As for NH3, the greater than 90% removal rate was achieved as long as the inlet concentration was controlled below 100 ppm at a flow rate of 27 L/hr. In the NH3 inlet, the apparent maximum removal and the apparent half-saturation constant were 1.88 x 10(-6) g-N/cell/day and 30.5 ppm, respectively. Kinetic analysis showed that 60 ppm of NH3 significantly suppressed the H2S removal by Pseudomonas putida, but H2S in the range of 5-60 ppm did not affect NH3 removal by Arthrobacter oxydans. Results from bioaerosol analysis in the bioreactor suggest that the co-immobilized cell technique applied for gas removal creates less environmental impact.

Ammonia↗