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Biomedical subjects

Hong Cheng

Publications and source records attributed to Hong Cheng.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Cytotoxic T lymphocyte antigen-4 promoter gene polymorphism is significantly associated with ulcerative colitis].

OBJECTIVE: Inflammatory bowel disease (IBD) is characterized by the T-cell excessive activation of intestinal mucosa. Cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) is a negative regulator of T-lymphocyte activation. The aim of the present study is to investigate the association between CTLA-4 promoter -1722 (T/C), -1661 (A/G) polymorphisms and ulcerative colitis (UC) in Han Chinese, in Hubei province of central China. METHODS: Eighty-seven patients with UC and 116 healthy controls were genotyped for CTLA-4 promoter -1722 and -1661 polymorphisms with a method of polymerase chain reaction based restriction fragment length polymorphism. RESULTS: The frequency of "A/G + G/G" genotype at the -1661 site was statistically higher in UC patients than in healthy controls (34.5% vs 15.5%, P = 0.002, OR = 2.865, 95% CI = 1.467-5.596). The frequency of the G allele at the -1661 site was also significantly higher in UC patients than in the controls (19.0% vs 8.2%, P = 0.002, OR = 2.624, 95% CI = 1.435-4.796). However, the distribution of the genotypes at -1722 site was not significantly different between the UC patients and the controls. CONCLUSION: The G allele of CTLA-4 promoter -1661 polymorphism showed a highly significant association with UC in Han Chinese of the central China.

Adult↗
PubMed2006

[Effects of flunarizine on T-type calcium channels in mouse spermatogenic cells].

OBJECTIVE: To investigate the effects of Flunarizine (Flu) on T-type calcium currents (ICaT) in spermatogenic cells. METHODS: Ca2+ currents were obtained in acutely dissociated mouse spermatogenic cells using whole-cell patch clamp technique and the effects of Flu on ICaT were observed. RESULTS: Flu of 0.1, 1, 10, 100 micromol/L inhibited ICaT in mouse spermatogenic cells significantly with the K50 value of 0.289 micromol/L (P < 0.05). With the holding potential at -90 mV and stimulating potential at -30 mV, the inhibition rates of Flu were (23.34 +/- 2.76)%, (46.04 +/- 3.52)%, (62.52 +/- 3.70)% and (73.52 +/- 3.12)%, respectively. CONCLUSION: Flu has significant inhibitory effects on ICaT in mouse spermatogenic cells, with concentration dependence. Ca(v)3.2 is the main contributor to T-type Ca2+ currents in spermatogenic cells.

Animals↗
PubMed2006

[Prevalence of overweight and obesity among children and adolescents in Beijing in 2004].

OBJECTIVE: To determine the current prevalence of overweight and obesity among children and adolescents (2-18 years) in Beijing and its distribution by age, gender and urban-rural residence. METHODS: As part of the Beijing Child and Adolescent Metabolic Syndrome Study, a stratified cluster representative sample of 23,422 children aged 0-18 years was selected. Anthropometric measures including weight and height were collected from 21,198 subjects aged 2-18 years from April to October in 2004. Overweight and obesity were defined according to body mass index [BMI, weight(kg)/height(m2)] cutpoints. For national and international comparisons, three sex-age-specific BMI criteria were used:1) The BMI cutoffs recommended by the Chinese Working Group on Obesity for Children (WGOC) aged 7-18 years; 2) The US 2000 CDC Growth Charts (CDC 2000) frac 34, the 85th and 95th percentiles; 3) The International Obesity Task Force (IOTF) reference. RESULTS: The overall combined prevalence of overweight and obesity was 18.6% with obesity as 8.1% based on the CDC 2000 criteria, The figures were 17.4% and 5.1% based on the IOTF criteria. According to the WGOC criteria, the combined prevalence of obesity was 20.9% and 8.9% in children aged 7-18 years. The combined prevalence was higher in school-age children (6-18 years) than in preschool-age children (19.8% vs. 14.8%, based on the CDC 2000 criteria). Among school-age children, the prevalence was higher in boys than in girls (26.7% vs. 16.5%), in urban than in rural areas (27.0% vs. 15.9%). However, these differences were not observed in preschool-age children. It was estimated that approximately 450 000 children from 2 through 18 years of age,were overweight or obesity in Beijing. CONCLUSION: Data from our study indicated that one fifth of the children and adolescents in Beijing were under overweight or obesity situation which was the highest in the nation. Obesity among children and adolescents in Beijing had already become a serious public health problem which deserved greater attention.

Adolescent↗
PubMed2005

Assessing the ecological security of the Tibetan plateau: methodology and a case study for Lhaze County.

A system for assessing the ecological security of Lhaze County in China's Tibetan Autonomous Region was developed using a pressure-state-response model and the analytic hierarchy process. We then used this model to comprehensively evaluate the status of ecological security in Lhaze County. Our results showed that the ecological environment in Lhaze County has deteriorated from an 'early stages of damage status' in the 1980s to 'moderately damaged status' today. This deterioration has become a major barrier to local economic development and social advancement. Natural and social aspects related to the population explosion, resource exploitation, and climate change that led to this ecological deterioration are discussed. Furthermore, we have suggested proposals for improving the ecological environment that include controlling population growth and enhancing the system of laws that protect the environment, upgrading 3 882.6 ha of low-yield farmland, planting 2 425.8, 548.8, and 1 207.4 ha of shelter belts for farmland protection, soil and water conservation, and fuelwood, respectively, and seeding 2 358.1 ha of artificial grassland. In the meantime, we propose strengthening the controls that limit soil and water loss, and optimizing industrial sectors that aspire to achieve high-efficiency, ecologically responsible agriculture.

China↗
PubMed2005

Matrine improves 2,4,6-trinitrobenzene sulfonic acid-induced colitis in mice.

Matrine is an alkaloid found in kinds of Sophora plants mainly including Sophora flavescens, Sophora alopecuroides and Sophora subprotrata. The aim of the present study was to evaluate therapeutic effects of matrine on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. Two hours following colonic instillation of TNBS, matrine with several doses was given by gastric gavage once daily for 7 days. Comparing with the 0.9% NaCl-treated mice with TNBS-induced colitis, matrine (10 and 20 mg kg(-1))-treated mice with TNBS-induced colitis were shown improvements of weight loss, macroscopic score, histological score, and myeloperoxidase (MPO) activity. Moreover, treatments with matrine (10 and 20 mg kg(-1)) decreased the up-regulated mRNA and protein levels of tumour necrosis factor-alpha (TNF-alpha) caused by TNBS. Our findings suggest that matrine improves TNBS-induced colitis in mice and the therapeutic mechanism might be related to the reduction of up-regulated colonic TNF-alpha production caused by TNBS.

Alkaloids↗
PubMed2005

Immunization with a single extracellular enveloped virus protein produced in bacteria provides partial protection from a lethal orthopoxvirus infection in a natural host.

Subunit vaccines that use the vaccinia virus extracellular envelope protein A33R alone or combined with other structural proteins are excellent candidates for a new smallpox vaccine. Since a new smallpox vaccine would be used in humans, who are the natural hosts for the Orthopoxvirus variola, the agent of smallpox, it would be important to determine whether a prospective smallpox vaccine can protect from a lethal Orthopoxvirus infection in a natural host. We addressed this question using the mouse-specific Orthopoxvirus ectromelia virus. We demonstrate that immunization with recombinant ectromelia virus envelope protein EVM135 or its ortholog vaccinia virus A33R produced in E. coli protects susceptible mice from a lethal ectromelia virus infection. This is the first report that a subunit vaccine can provide protection to a lethal Orthopoxvirus infection in its natural host.

Animals↗
PubMed2005

[The epidemiology of Helicobacter pylori resistance to antibiotics in Beijing].

OBJECTIVE: To investigate the prevalence of Helicobacter pylori (H. pylori) resistance to metronidazole, clarithromycin and amoxicillin in Beijing. METHODS: H. pylori strains were cultured from the gastric biopsy samples obtained from 159 patients with upper abdominal symptoms by gastroendoscopy. Minimal inhibitory concentrations of antibiotics were determined by E-test method. RESULTS: The resistance rates of H. pylori to metronidazole and clarithromycin in Beijing were 36.0% (18/50) and 10.0% (5/50) in 1999-2000, 43.1% (47/109) and 18.3% (20/109) in 2001-2002, respectively. H. pylori resistance to both metronidazole and clarithromycin were 10.0% (5/50) in 1999-2000 and 14.7% (16/109) in 2001-2002. Only one strain was found resistant to amoxicillin in 49 patients. CONCLUSION: The resistance rates of H. pylori to metronidazole and clarithromycin were increased in Beijing in recent years. The strains resistant to amoxicillin were rare.

Adolescent↗
PubMed2005

Methodologic issues in follow-up studies of cancer incidence among occupational groups in the United States.

PURPOSE: Incidence studies of occupational factors and cancer in the United States are problematic because the use of population-based registries to identify cases requires development of historical data on subjects' residences and often severely restricts the time period of follow up. This article describes procedures for addressing these challenges. METHODS: We used data from studies of cancer incidence and mortality among microelectronics industry employees to assess various methods for developing residential histories and the relative informativeness of the two studies. RESULTS: We developed residential histories for 98% of 99,229 mortality study subjects. Analyses making alternative assumptions about residential histories yielded standardized incidence ratios varying by at most 6%. Use of postemployment residential histories increased person-years by up to 62% and increased the observed number of cancers by up to 28%. The proportion of mortality study person-years included in the cancer incidence study ranged from 40% to 77% among work activity subcohorts. The number of observed cancer cases in the incidence study was 60% higher than the number of observed cancer deaths in the mortality study. CONCLUSIONS: Assumptions about residential history had little impact on validity. Use of information sources with national coverage to develop residential histories increased the incidence study's precision. Despite geographic and temporal restrictions, incidence studies provide more data than mortality studies on cancers with good survival. However, the potential for selection bias in incidence studies may vary considerably among subcohorts, indicating the need for cautious interpretation of such research.

Adult↗
PubMed2005

Network constrained clustering for gene microarray data.

UNLABELLED: Many bioinformatics problems can be tackled from a fresh angle offered by the network perspective. Directly inspired by metabolic network structural studies, we propose an improved gene clustering approach for inferring gene signaling pathways from gene microarray data. Based on the construction of co-expression networks that consists of both significantly linear and non-linear gene associations together with controlled biological and statistical significance, our approach tends to group functionally related genes into tight clusters despite their expression dissimilarities. We illustrate our approach and compare it to the traditional clustering approaches on a yeast galactose metabolism dataset and a retinal gene expression dataset. Our approach greatly outperforms the traditional approach in rediscovering the relatively well known galactose metabolism pathway in yeast and in clustering genes of the photoreceptor differentiation pathway. AVAILABILITY: The clustering method has been implemented in an R package "GeneNT" that is freely available from: http://www.cran.org.

Algorithms↗
PubMed2005

Recruitment of the human TREX complex to mRNA during splicing.

In yeast, the TREX complex contains the THO transcription elongation complex, which functions in direct cotranscriptional recruitment of the mRNA export proteins Sub2 and Yra1 to nascent transcripts. Here we report the identification of the human THO complex and show that it associates with spliced mRNA, but not with unspliced pre-mRNA in vitro. Transcription is not required for this recruitment. We also show that the human THO complex colocalizes with splicing factors in nuclear speckle domains in vivo. Considering that splicing occurs cotranscriptionally in humans, our data indicate that recruitment of the human TREX complex to spliced mRNA is not directly coupled to transcription, but is instead coupled to transcription indirectly through splicing.

Exodeoxyribonucleases↗
PubMed2005

Beta-endorphin ameliorates synovial cell hyperfunction in the collagen-induced arthritis rat model by specific downregulation of NF-kappa B activity.

OBJECTIVES: To observe the multiple immunoregulating effects of beta-endorphin (beta-END) on synovium cells of collagen-induced arthritis (CIA) in rats and to determine whether the regulation involves the transcriptional factor-kappaB (NF-kappaB) signal pathway. METHODS: CIA was induced in female Wistar rats by immunization with native bovine type-II collagen emulsified with complete Freund's adjuvant. Synovial cells in the knees of the CIA rats were cultivated, and the effects of beta-END, beta-END receptor inhibitor (naloxone, Nal) in proliferation and apoptosis of the synovial cells were assayed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, flow cytometry, and DNA integrity, respectively. The effects of beta-END and Nal on mRNA expression of several cytokines in the synovial cells, including tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, regulated upon activation normal T-cell expressed and secreted (RANTES), inducible nitric oxide synthase (iNOS), matrix metalloproteinase-2 (MMP-2) and MMP-9 were estimated by quantitative reverse transcription-polymerase chain reaction. Effects of beta-END and Nal on NF-kappaB activity were analyzed using luciferase gene reporter assays. The effects of beta-END and Nal on p65NF-kappaB expression of the synovial cells were examined using Western blot. RESULTS: 75% of the rats were demonstrated to have established the CIA model successfully. beta-END was shown to exert multiple effects on synovial cells of CIA rats including decreased proliferation, induced apoptosis, and downregulation of TNF-alpha, IL-1beta, IL-6, RANTES, iNOS, MMP-2 and MMP-9 mRNA expression. beta-END seemed to play an immunoregulating role by downregulating the activity and expression of NF-kappaB. It was found that the beta-END receptor blockage could counteract all the effects. CONCLUSIONS: beta-END ameliorates synovial cell functions of CIA rats through binding with receptors and downregulating the NF-kappaB signal pathway. This suggests that beta-END, by blocking the activity and expression of NF-kappaB, is a potential anti-inflammatory and anti-rheumatic agent against CIA.

Analysis of Variance↗
PubMed2005

Development of alpha-keto-based inhibitors of cruzain, a cysteine protease implicated in Chagas disease.

Trypanosoma cruzi, a protozoan parasite, is the causative agent of Chagas disease, a major cause of cardiovascular disease in many Latin American countries. There is an urgent need to develop an improved therapy due to the toxicity of existing drugs and emerging drug resistance. Cruzain, the primary cysteine protease of T. cruzi, is essential for the survival of the parasite in host cells and therefore is an important target for the development of inhibitors as potential therapeutics. A novel series of alpha-ketoamide-, alpha-ketoacid-, alpha-ketoester-, and aldehyde-based inhibitors of cruzain has been developed. The inhibitors were identified by screening protease targeted small molecule libraries and systematically optimizing the P1, P2, P3, and P1' residues using specific structure-guided methods. A total of 20 compounds displayed picomolar potency in in vitro assays and three inhibitors representing different alpha-keto-based inhibitor scaffolds demonstrated anti-trypanosomal activity in cell culture. A 2.3A crystallographic structure of cruzain bound with one of the alpha-ketoester analogs is also reported. The structure and kinetic assay data illustrate the covalent binding, reversible inhibition mechanism of the inhibitor. Information on the compounds reported here will be useful in the development of new lead compounds as potential therapeutic agents for the treatment of Chagas disease and as biological probes to study the role that cruzain plays in the pathology. This study also demonstrates the validity of structure-guided approaches to focused library design and lead compound optimization.

Amides↗
PubMed2005

TREX, SR proteins and export of mRNA.

The machineries involved in gene expression are highly conserved from yeast to metazoans. However, a fundamental difference between these organisms is that most yeast genes lack introns whereas the converse is true in higher organisms. Recent studies of the TREX complex, which functions in mRNA export, unexpectedly revealed that this complex is recruited by the transcription machinery in yeast whereas the TREX complex appears to be recruited by the splicing machinery in mammals. Studies during the past year also revealed a possible conserved role for SR protein dephosphorylation in regulating the interaction between SR proteins and the mRNA export receptor TAP (Mex67 in yeast). There is also an interesting possibility that an SR protein-TREX complex interaction is a conserved part of the mRNA export machinery.

Active Transport, Cell Nucleus↗
PubMed2005

Whole-genome amplification: relative efficiencies of the current methods.

Whole genome amplification (WGA) has emerged as a fundamental method for DNA analysis from limited quantities of genomic DNA in forensic analysis and disease gene discovery. Several strategies for WGA have been developed during the past decade, each with variable fidelity, yield and coverage of the amplified genome. In the search for a reliable and robust WGA method for genotyping short tandem repeat (STR) loci and single nucleotide polymorphic (SNP) markers, we initially tested four common methods, viz., degenerate oligonucleotide primed PCR (DOP), primer extension preamplification (PEP), improved-PEP (I-PEP) and multiple displacement amplification (MDA), typing the 13 CODIS tetranucleotide repeat loci. The results showed among all methods, I-PEP and MDA have higher genomic coverage. DOP and PEP produced locus and allelic dropouts. Therefore, we emphasized on the evaluation of I-PEP and MDA protocols, which shows that the two methods have their relative strengths and weaknesses. In general, the product yield of MDA is higher than that of I-PEP. However, the specificity of the I-PEP products appears to be higher, particularly in the analysis of STR loci. In the analysis of SNP markers, some loci amplify better using products obtained from I-PEP whereas some worked better with MDA. Our analyses also demonstrate that blood spots on FTA cards are a more efficient source of DNA for I-PEP as compared to MDA, especially for STR analysis.

Allelic Imbalance↗
PubMed2005

Exposure assessment for retrospective follow-up studies of semiconductor- and storage device-manufacturing workers.

OBJECTIVE: This exposure assessment was conducted in the first large study of mortality and cancer incidence in semiconductor and storage device manufacturing. METHODS: Unique combinations of division, department and job codes and names (DDJ) from work history records were assigned to work groups and exposure categories. Agent exposure matrices assessed differences in potential exposures between groups. Changes in exposure over time were tracked by dividing the production history into manufacturing eras. RESULTS: Nineteen work groups were developed to capture 310,351 unique DDJs from 1965-1999. Agent exposure matrices contrasted exposure potential to solvents, metals, and work in cleanrooms between groups, and three manufacturing eras were identified for each site. CONCLUSIONS: The work groups, manufacturing eras and agent matrices have been used to classify workers in the study of cancer incidence and mortality.

Computer Storage Devices↗
PubMed2005

Mortality among semiconductor and storage device-manufacturing workers.

PROBLEM: We evaluated mortality during 1965 to 1999 among 126,836 workers at two semiconductor facilities and one storage device facility. METHOD: We compared employees' cause-specific mortality rates with general population rates and examined mortality patterns by facility, duration of employment, time since first employment, and work activity. RESULTS: Employees had lower-than-expected mortality overall (6579 observed deaths, standardized mortality ratio [SMR] = 65; 95% confidence interval [CI] = 64-67), for all cancers combined (2159 observed, SMR = 78, 95% CI = 75-81) and for other major diseases. Central nervous system cancer was associated with process equipment maintenance at one of the semiconductor facilities (10 observed, SMR = 247, 95% CI = 118-454). Prostate cancer was associated with facilities/laboratories at the storage device facility (18 observed, SMR = 198, (5% CI = 117-313). CONCLUSIONS: Further evaluation of workplace exposures or independent investigations of similar occupational groups may clarify the interpretation of associations observed in this study.

Adult↗
PubMed2005

Ectopic cervical anaplastic ependymoma.

Ependymomas generally arise in the central nervous system (CNS), although rare primary extraneural ependymomas have been observed. Reported herein for the first time is the case of a patient with primary ectopic cervical anaplastic ependymoma. The tumor was found in the right neck root region of a 35-year-old man. No additional tumor was found in the CNS or in other parts of the body. The patient received surgery and post-surgical local radiotherapy. Microscopically, the tumor consisted of round to oval cells with fine chromatin, distinct nucleoli, moderate nuclear atypia and numerous mitoses (>25/10 high-power fields) in a densely cellular growth pattern with characteristic fibrillary cytoplasm and formation of perivascular pseudorosettes. By immunohistochemistry, the tumor cells were positive for glial fibrillary acidic protein, epithelial membrane antigen (EMA), vimentin and S-100 protein. EMA staining showed a membranous as well as a paranuclear pattern of immunoreactivity. Electron microscopic studies revealed that tumor cells form micro rosettes, into which microvilli and cilia projected. The diagnosis was World Health Organization grade III anaplastic ependymoma. There is no evidence of local tumor recurrence or distant metastasis after 30 months follow up. The present case adds yet another unique example to the already diverse spectrum of head and neck neoplasms encountered in surgical pathology.

Adult↗