A novel regulator inhibits HBV gene expression.
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Cycloheximide↗
Biomedical subjects
C Chang
Publications and source records attributed to C Chang.
Analysis of T cell receptor Vbeta gene usage during the course of disease in patients with chronic hepatitis B.
The T cell receptor (TCR) is a heterodimeric molecule expressed on the surface of T cells and recognizes foreign peptides presented by the major histocompatibility complex on the surface of antigen-presenting cells or virus-infected cells. Analysis of TCR usage by T cells which recognize hepatitis B virus (HBV) provides further insight into the participation of T cell populations during the course of disease. In this study, we examined the T-cell-proliferative response and the TCR Vbeta gene usage of peripheral blood mononuclear cells in 3 patients with clinical evidence typical of chronic hepatitis B. All 3 patients had significant T-cell proliferative responses against HBV core antigen (HBcAg) during the remission stage, while no responses were detected during the acute exacerbation stage. In addition, the TCR Vbeta7 gene was utilized more frequently in T cells recognizing HBcAg during remission, while TCR Vbeta1 and Vbeta2 were utilized at a higher percentage during acute exacerbation. On the contrary, the T cell proliferative response against HBV surface antigen was undetectable and no specific Vbeta gene was utilized more frequently by all 3 patients, regardless of disease state. Our longitudinal studies, although based on a small sample of patients, demonstrate that the population of HBcAg-activated T cells alters during the course of disease in chronic hepatitis B patients.
Genes, Immunoglobulin↗
Hepatitis B viral polymerase fusion proteins are biologically active and can interact with the hepatitis C virus core protein in vivo.
Hepadnaviruses and retroviruses are evolutionarily related families because they both require a process of reverse transcription for genome replication. However, hepadnaviruses produce polymerase (pol) and core proteins separately, while retroviruses synthesize a gag-pol fusion protein that is subsequently cleaved by a virally encoded protease to release a functional polymerase. To test whether an additional sequence at the N-terminus of pol in hepatitis B virus (HBV) interferes with its function, we created two plasmids expressing core-pol fusion proteins, core144-pol and core31-pol. Secreted particles obtained from HuH-7 cells, which were cotransfected with a core-pol fusion protein-expressing plasmid and a core-expressing plasmid, showed a positive signal of HBV DNA by the endogenous polymerase assay, indicating that the core-pol fusion proteins retain DNA priming, polymerization and RNase H activities. The fusion protein was detected in the cytoplasm of transfected cells and in secreted virions by immunoprecipitation. Furthermore, we found by immunofluorescence staining that the HBV core-pol fusion protein colocalized with the hepatitis C virus (HCV) core protein in cytoplasm and in lipid droplets. Immunoprecipitation studies showed that the anti-HCV core complex contained the HBV core-pol fusion protein while the anti-HBV pol complex contained the HCV core protein, which supports the hypothesis that the HCV core protein can form a complex with the HBV core-pol fusion protein.
Cytoplasm↗
Studies on a new antimalarial compound: pyronaridine.
Pyronaridine, a hydroxyanilino-benzonaphthyridine derivative synthesized in 1970, is a new antimalarial compound which has been in use in China for more than 10 years. The drug is highly effective against Plasmodium falciparum and P. vivax. Furthermore, it is efficacious in combatting chloroquine-resistant strains of falciparum malaria both in vitro and in vivo, in human patients. Extensive field studies involving several thousand cases have shown that pyronaridine has promising therapeutic value in the treatment of malarial infection, including chloroquine-resistant infections. Pyronaridine given orally, intramuscularly or by intravenous drip is not only effective against malaria but also has low toxicity.
Animals↗
Eukaryotes have "two-component" signal transducers.
The eukaryotic proteins discussed above share a number of amino acid sequence features with prokaryotic members of the two-component signal transducer family. ETR1 and Sln1 each contain putative HPK and receivers, while Skn7 has similarity to receivers only. The other proteins--phytochromes, BCKDH kinase and the dr6 gene product--appear to be distant relatives of the two-component family because they have less-conserved motifs, although even biochemically defined prokaryotic family members can lack conserved motifs (Parkinson and Kofoid, 1992). The eukaryotic and prokaryotic proteins also show similar diversity with respect to the arrangements of the components; transmitters and receivers can lie within the same protein (for example, ETR1 and Sln1 in eukaryotes and BarA and LemA in prokaryotes) or receivers can lie on a separate protein (for example, Skn7 in yeast and CheY in bacteria (Stock et al., 1985)). The new eukaryotic members of the two-component family raise a number of questions, especially since their functions are not yet clearly defined. The identities of the signals transduced are unknown, except for the red light signal for phytochrome. Ethylene is presumably the signal for ETR1, but this has not been demonstrated directly. It also remains to be seen whether eukaryotic two-component modules are functionally homologous to the prokaryotic two-component systems; eukaryotic modules could be utilized in uncharacterized ways, possibly in combination with different signalling components. Among the eukaryotic proteins discussed here, BCKDH kinase has the best-understood function, yet its substrate is not an orthodox response regulator, and moreover, the substrate is phosphorylated at serine residues.
Arabidopsis↗
Brush cytology during ERCP for the diagnosis of biliary and pancreatic malignancies.
Endoscopic retrograde cholangiopancreatography is a valuable tool in the diagnosis and management of pancreaticobiliary diseases. The diagnostic sensitivity of brush cytology is reported as between 18% and 70% for malignant bile duct or pancreatic duct strictures. We report our findings in 74 patients with pancreaticobiliary strictures who underwent ERCP. Brush cytology was performed on 55 bile duct specimens and 19 pancreatic duct specimens. No complications related to the procedure occurred; 4 specimens (5.4%) were unsatisfactory for interpretation. Strictures were benign in 22 patients (12 pancreatitis, 5 sclerosing cholangitis, 3 Mirizzi syndrome, and 2 papillitis) and malignant in 52 patients (29 pancreatic carcinoma, 10 cholangiocarcinoma, 6 metastatic disease, 4 pancreatic mucinous ductal ectasia, 1 ampullary carcinoma, and 2 non-functioning islet cell tumors). The nature of the stricture was confirmed by surgery, surgical biopsy, necropsy, or follow-up. The overall results for brush cytology were sensitivity 56.2%, specificity 100%, positive predictive value 100%, negative predictive value 51.2%, and accuracy 70%. Our results confirm the value, safety, and utility of obtaining cytologic specimens at the time of ERCP; confirmation was obtained in 65.5% of pancreatic carcinoma cases. Although a negative result does not exclude pancreaticobiliary malignancy, a positive result confirms this diagnosis.
Bile Duct Neoplasms↗
Epidemic keratoconjunctivitis caused by a new genotype of adenovirus type 8 (Ad8)-a chronological review of Ad8 in Southern Taiwan.
PURPOSE: To understand the pathogenic evolution of viral keratoconjunctivitis in Kaohsiung, Taiwan, a retrospective molecular and clinical analysis was conducted. METHODS: From January 1990 to December 1994, conjunctival swab samples from patients suspected of having viral conjunctivitis were collected for viral culture isolation, neutralization test (NT), and endonuclease cleavage analysis. Six restriction endonucleases, comprising HindIII, BamHI, SalI, SstI, SmaI, and PstI, were used for cleavage. Clinical examinations of patients were performed by two senior ophthalmologists. RESULTS: Twenty-one cases of a new genotype of adenovirus (Ad) type 8, designated as Ad8H, were discovered in the 27 detected adenovirus cases. The Ad8H has a distinct cleavage pattern, especially by HindIII and SalI. The Ad8H keratoconjunctivitis induced more subconjunctival hemorrhage (33.3%), keratitis (33.3%), and lymphadenopathy (85.7%) than other genotypes of Ad8 previously isolated in Kaohsiung, Taiwan. CONCLUSION: We have discovered a new genotype, Ad8H, which was prevalent as the main pathogen of the adenoviral keratoconjunctivitis in Kaohsiung, Taiwan from 1990 to 1994. Adenovirus type 8 is evolving into more genotypes with a trend towards more severe symptoms, including subconjunctival hemorrhage, keratitis, and lymphadenopathy.
Adenoviridae Infections↗
An investigation of the antitumor activity of Micromelum integerrimum (Rutaceae).
Extracts of Micromelum integerrimum (Buch.-Ham. ex Coleb.) M. Roem. were fractionated based on in vivo activity in mice in the P-388 lymphocytic leukemia system. Activity in ethanol extracts was concentrated in the chloroform partition fraction, which was further resolved by chromatography on silica gel. The known coumarins, micromelin and scopoletin, were crystallized from the active fractions and demonstrated to have antitumor activities. Micromelin was converted to the corresponding butenolide (deoxymicromelin) which was inactive in the 9KB assay.
Animals↗
Menopause and hormone using experiences of Chinese women in Taiwan.
The purpose of this study was to explore the menopause experiences of Chinese women in Taiwan. Six hundred and seventy-three women, aged 40 to 60 years, in the Taipei metropolitan area were chosen as the sample. These women were categorized into four groups in terms of their menopausal experiences: surgical menopause, natural menopause, perimenopause, and premenopause. The results show that the three most frequently reported discomforts that women experienced during menopause were backache/lumbago, amentia, and tiredness. The frequency of reported discomforts was low compared with frequencies reported in Western countries. The surgical group reported higher rates of symptoms than others. In addition, the hormone use rate was 13.5% for the natural menopause group, 34.4% for the surgical menopause group, 12% for the perimenopause group, and 1.9% for the premenopausal group. Higher hormone use rates were inconsistent with the general negative attitudes toward hormone use in Chinese society. Among those 59 women ever using hormones, only one third reported improvement in their symptoms. Women in Taiwan have an inadequate knowledge of menopause. Further health care education and research are needed.
Adult↗
Phosphorus accumulation in cultivated soils from long-term annual applications of cattle feedlot manure.
Historically, manure has been recognized as an excellent soil amendment that can improve soil quality and provide nutrients for crop production. In areas of high animal density, however, the potential for water pollution resulting from improper storage or disposal of manure may be significant. The objective of this study was to determine the P balance of cultivated soils under barley (Hordeum vulgare L.) production that have received long-term annual manure amendments. Nonirrigated soils at the study site in Lethbridge, AB, Canada, have received 0, 30, 60, or 90 Mg manure ha(-1) (wet wt. basis) while irrigated plots received 0, 60, 120, and 180 Mg ha(-1) annually for 16 yr. The amount of P removed in barley grain and straw during the 16-yr period was between 5 and 18% of the cumulative manure P applied. There was a balance between P applied in manure and P recovered in crops and soils (to the 150-cm depth) of nonirrigated plots during the 16-yr study. In irrigated plots, as much as 1.4 Mg P ha(-1) added (180 Mg ha(-1) yr(-1) treatment) was not recovered over 16 yr, and was probably lost through leaching. The risk of ground water contamination with P from manure was greater in irrigated than nonirrigated plots that have received long-term annual manure amendments. Manure application rates should be reduced in nonirrigated and irrigated plots to more closely match manure P inputs to crop P requirements.
Agriculture↗
Greenhouse gas emissions during cattle feedlot manure composting.
The emission of greenhouse gases (GHG) during feedlot manure composting reduces the agronomic value of the final compost and increases the greenhouse effect. A study was conducted to determine whether GHG emissions are affected by composting method. Feedlot cattle manure was composted with two aeration methods--passive (no turning) and active (turned six times). Carbon lost in the forms of CO2 and CH4 was 73.8 and 6.3 kg C Mg-1 manure for the passive aeration treatment and 168.0 and 8.1 kg C Mg-1 manure for the active treatment. The N loss in the form of N2O was 0.11 and 0.19 kg N Mg-1 manure for the passive and active treatments. Fuel consumption to turn and maintain the windrow added a further 4.4 kg C Mg-1 manure for the active aeration treatment. Since CH4 and N2O are 21 and 310 times more harmful than CO2 in their global warming effect, the total GHG emission expressed as CO2-C equivalent was 240.2 and 401.4 kg C Mg-1 manure for passive and active aeration. The lower emission associated with the passive treatment was mainly due to the incomplete decomposition of manure and a lower gas diffusion rate. In addition, turning affected N transformation and transport in the window profile, which contributed to higher N2O emissions for the active aeration treatment. Gas diffusion is an important factor controlling GHG emissions. Higher GHG concentrations in compost windrows do not necessarily mean higher production or emission rates.
Animal Feed↗
Hydrological properties of a clay loam soil after long-term cattle manure application.
Limited information exists on the effect of long-term application of beef cattle (Bos taurus) manure on soil hydrological properties in the Great Plains region of North America. A site on a clay loam soil (Typic Haploboroll) was used to examine the effect of manure addition on selected soil hydrological properties in 1997 and 1998. The manure was annually applied in the fall for 24 yr at one, two, and three times the recommended rates (in 1973) under dryland (0, 30, 60, and 90 Mg ha(-1) wet basis) and irrigation (0, 60, 120, and 180 Mg ha(-1)). Manure significantly (P < or = 0.05) increased soil water retention (0-5 and 10-15 cm) by 5 to 48% compared with the control at most potentials between 0 and -1500 kPa. Field soil water content (0-5 and 10-15 cm) was increased by 10 to 22% in the summers of 1997 and 1998. Manure increased ponded infiltration by more than 200% at 90 Mg ha(-1) under dryland (1998) and at rates > or = 120 Mg ha(-1) under irrigation (1997). Field-saturated hydraulic conductivity (Kfs) of surface soil (1-cm depth) was significantly increased by 76 to 128% under dryland (1998) and irrigation (1997), as were number of pores > 1120 microm in diameter (37-128% increase). In contrast, manure rate had little or no effect on unsaturated hydraulic conductivity [K(psi)] values (-0.3, -0.5, -0.7, and -1.0 kPa) in 1997 and 1998. Overall, soil hydrological parameters generally had a neutral or positive response to 24 yr of annual manure addition.
Agriculture↗
Seroepidemiology of Bartonella vinsonii subsp. berkhoffii infection in California coyotes, 1994-1998.
The prevalence of antibodies to Bartonella vinsonii subsp. berkhoffii in coyotes (Canis latrans) in California ranged from 51% in central to 34% in southern and 7% in northern California. Seropositive coyotes were more likely to be from coastal than inland counties (p clustered distribution of Bartonella seropositivity in coyotes suggests that B. vinsonii subsp. berkhoffii infection is vectorborne. Further investigation is warranted to evaluate which arthropods are vectors and what the mode of transmission is from wildlife to domestic dogs and possibly humans.
Animals↗
Identification and characterization of androgen receptor associated coregulators in prostate cancer cells.
The androgen receptor (AR) is a member of the nuclear receptor (NR) superfamily that mediates the effects of androgens on target tissues. Over the last decade, it has become apparent that NRs require accessory factors for optimal activation of target gene expression. Numerous NR coregulators have been identified, with diverse structures and potential mechanisms of coregulation, creating an increasingly complicated picture of NR action. Due to the expanding complexity of the coregulator field, this review will focus on the AR ligand-binding domain (LBD) and N-terminal interacting proteins identified by our lab. The LBD-interacting proteins ARA70, ARA55 and ARA54 were first characterized and ARA70 was found to have a relatively higher specificity for the AR in human prostate cancer DU145 cells. Characterization of the functional relationship between the AR and these coregulators indicated that ARA70 and ARA55 could enhance the androgenic effects of 17beta-estradiol (E2) and hydroxyflutamide (HF), an antiandrogen commonly used in the treatment of prostate cancer. ARA160, an AR N-terminal interacting protein also known as TATA element modulatory factor (TMF), was subsequently shown to cooperate with ARA70 in enhancing AR activity. Another AR N-terminal interacting protein, ARA24, interacted with the poly-Q tract, a region within the N-terminus of the AR linked to Kennedy's disease (X-linked spinal and bulbar muscular atrophy). More recently, our lab has identified ARA267, a SET domain containing protein, and supervillin, an F-actin binding protein, as AR coregulators. Collectively, the data from these studies indicate that these coregulators are necessary for optimal AR transactivation. Interruption of the interaction between AR and these proteins may serve as a new therapeutic target in the treatment of prostate cancer.
Acetyltransferases↗
[A method of manufacturing a universal electrode with a microsyringe].
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Electrophysiology↗
A smoking cessation intervention for head and neck cancer patients: trial design, patient accrual, and characteristics.
This paper describes the aims, study design, and patient accrual and characteristics from an ongoing randomized controlled trial evaluating a surgeon- and dentist-delivered smoking cessation intervention for head and neck cancer patients. Subjects (n = 186) accrued into the trial are profiled in terms of demographics, medical and treatment descriptors, smoking history and behavior at enrollment, and related psychosocial variables (mood, adherence indicators, and alcohol consumption). These patients have long histories of tobacco use, moderate to high levels of nicotine dependence, and a lack of overt mood disturbance and are receptive to behavioral change.
Affect↗
A morphologic and morphometric study of cells from colloid carcinoma of the breast obtained by fine needle aspiration. Distinction from other breast lesions.
Morphologic and morphometric studies were carried out on eight cases of pure and mixed colloid carcinoma of the breast initially diagnosed by fine needle aspiration (FNA). Key morphologic features included (1) cellular smears, (2) single cells, loose aggregates and cohesive groups of cells bathed in a mucinous background, (3) single cells displaying nuclear eccentricity and (4) little variation in nuclear size or shape, with bland-to-accentuated chromatin and rare nucleoli. These morphologic features are compared with those observed in pregnancy adenoma, lobular carcinoma, fibroadenoma, ductal carcinoma and medullary carcinoma. A morphometric study employing the major and minor axes of the nucleus, its axis product and axis ratio was also performed. Statistical treatment confirmed that the nuclear axis product (a size factor) distinguished colloid carcinoma from the other breast lesions, except the small-cell type of ductal carcinoma. Furthermore, the nuclear axis ratio (a shape factor) discriminates pregnancy adenoma and small-cell ductal carcinoma from the other breast lesions studied. By combining morphologic and morphometric criteria, one can specifically separate colloid carcinoma from the other breast lesions when examining smears obtained by FNA. Since colloid carcinoma is usually composed of cells with a relatively benign-appearing cytomorphology, the importance of recognizing this entity in fine needle aspirates is emphasized.
Adenocarcinoma, Mucinous↗
Developmental stages of Chinese children's concepts of health and illness in Taiwan.
This research showed that conceptual development of health and illness of Chinese children in Taiwan follows the general pattern of Piaget's levels of development. But Reichenbach's hypotheses of social influence explained the incongruencies in the data. Questionnaire and unstructured interview were used to explore the conceptual development of 468 children who were grouped according to their educational level: kindergarten, first and second grades, third and fourth grades, as well as fifth and sixth grades. Results showed that children in general defined illness and health based on physiological dysfunction. The older school children attributed "inappropriate behaviors" as the cause of illness more than young school children did. Nearly a quarter of the kindergarten group appeared to be at Piaget's level of "phenomenism" when asked to explain the cause of illness. Children also relied on "external resources" as the method to treat illness; younger school children emphasized "medicine treatment". In addition, all children believed "appropriate behaviors" can promote health, but awareness of psychological health did not appear until third and fourth grades.
Attitude to Health↗