Search PubMed⌕ Search

Biomedical subjects

Z Feng

Publications and source records attributed to Z Feng.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Regulatory effect of Bcl-2 on the cortical neurons of primary cultured mice with HSV-1 infection].

OBJECTIVE: To study the effect of Bcl-2 on the cortical neurons of primary cultured mice with HSV-1 infection. METHODS: Analysis of the expression of Bcl-2 on the cortical neurons of primary cultured fetal mice in vitro infected with HSV-1 for 11 hours or exposed to sorbitol for 5 hours was made by flow cytometry and Western blotting. RESULTS: The Bcl-2 of the cultured neurons undergoing HSV-1 infection expressed upregulating compared with the mock untreated neurons. The Bcl-2 protein of HSV-1 infected and exposed to sorbitol neurons expressed upregulating compared with the control group. The Bcl-2 protein of the primary cultured 3 day cells expressed higher than that of the primary cultured 7 day cells. The higher neurovirulence, the higher expression of Bcl-2. CONCLUSIONS: Bcl-2 might protect the primary cultured cortical neurons of fetal mice from apoptosis where infected with HSV-1, and thereby the lifespan of host cells may be prolonged.

Animals↗
PubMed2001

[Detection of radiation-induced apoptosis in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the pathological changes after radiotherapy and its clinical significance of nasopharyngeal carcinoma (NPC). METHOD: Paraffin-embedded tissue blocks obtained from 30 cases of NPC before and during radiotherapy were used in this study. Using terminal oxynucleotidyl transferase mediated dUTP biotin nick end labeling (TUNEL) and HE staining, the spontaneous and radiation-induced apoptotic rate (AR) were examined, and the pathological changes of NPC tissues before and after radiotherapy were compared. RESULT: The AR of radiation-induced apoptosis was significant higher than that of spontaneous apoptosis, but the AR was decreasing and the differentiation of proliferatic tumor clonogehic cell getting better during radiotherapy of NPC. CONCLUSION: The process of apoptosis was accelerated and the differentiation of proliferative tumor clonogehic cell getting better during radiotherapy of NPC.

Adolescent↗
PubMed2001

Cloning and expressing of the three repeat fragments of Plasmodium falciparum 11.1 gene.

OBJECTIVE: To clone and express the 3R, 6R and 9R repeat fragments of Plasmodium falciparum(Pf11.1) gene. METHODS: Three repeat fragments from the genomic DNA of Plasmodium falciparum 3D7 strain cultivated were amplified by using the designed primers. The PCR products were cloned into the pT7 vector for bi-direction sequencing. The sequencing results were analysised by GENETYX-MAC. And then the amplified fragments were subcloned into pET32a(+) or pET32b(+) in order to express the recombinant proteins under the induction of IPTG in E. coli BL21. RESULTS: 3R,6R and 9R fragments with sizez of 552 bp, 630 bp and 444 bp respectively were successfully amplified by PCR. The sequence analysis showed that there were 4 more 3AA units and one more 6AA unit in Pf11.1 gene of 3D7 strain as compared with Palo Alto strain. The homologies of the nucleotide sequence between the 3R fragment and the 6R fragment of the two strains were 92.8% and 95.1%, respectively. The amplified 9R fragment contains 139AA repeat units. The three recombinant proteins were expressed in BL21 strain with molecular weights of 45, 60 and 42 kDa. CONCLUSION: We got the 3R, 6R and 9R fragments separately by PCR and expressed them in E. coli successfully. The Pf11.1 gene of 3D7 strain is highly homologous to that of the Palo Alto strain.

Animals↗
PubMed2001

[Preliminary study on cytochrome C oxidase 1 gene of Oncomelania hupensis from Miao River area in Hubei province].

OBJECTIVE: To study the mitochondrial cytochrome C oxidase 1(CO1) gene of Oncomelania snails from Miao River area in Hubei Province. METHODS: Oncomelania snails were collected from Miao River area, including upstream and downstream. Genomic DNA was extracted from the tissue of the snail. PCR was used to amplify a fragment of the CO1 gene. Sequences of the CO1 fragment were determined directly from the purified PCR products by an automated sequencer. Sequences for each individual were assembled and edited using ESEE 3.0 s. A distance matrix was computed using program DNADISt of PHYLIP(3.57). Unrooted maximum likelihood trees were calculated from program FITCH. RESULTS: The amplified CO1 gene of the snail was a fragment of 638 bp in length. Sequence analysis showed that the accumulated variable sites were significant different between upstream and downstream populations, being 29 and 46, respectively. From the number of variable sites in the gene, snails in this area were roughly separated into two groups. Each of them was a mixture of both upstream and downstream snails. Same haplotypes were confirmed to be present among the collected sites along the river. From the distance matrix of sequence divergence, the population upstream vs downstream differed by 0.0221 +/- 0.0105. CONCLUSION: There were more variation in downstream population than that in upstream. Gene flow was identified in these populations. The phylogenetic trees suggest the existence of two groups, but all of them belong to 0. h. hupensis.

Animals↗
PubMed2000

Cloning and expression of MP13 gene from rat hippocampus, a new factor related to guanosine triphosphate regulation.

C-Fos and the Fos-related antigens (FRA) are induced by various stimuli. A novel 35-37 kDa FRA was induced much longer after the treatment using kainic acid (KA) and may be very important for neuronal survival after brain damage. To identify this long-term FRA, we have constructed a cDNA library derived from hippocampus after KA treatment and screened it with an antibody highly conserved M-peptide region of FRAs. One gene, MP13, was cloned with a 1662 bp open reading frame and coded for a 554-amino acid protein. MP13 has a leucine zipper region, a glutamine repeat region, and has high similarity to the activator of the small guanosine triphosphate (GTP)ase Rab5. Gel retardation analysis revealed that MP13 functions as a GTP regulation related factor.

Amino Acid Sequence↗
PubMed2000

Comparison of efficacy and side effects of combination therapy of angiotensin-converting enzyme inhibitor (benazepril) with calcium antagonist (either nifedipine or amlodipine) versus high-dose calcium antagonist monotherapy for systemic hypertension.

The present 2 multicenter studies were designed to evaluate whether patients with essential hypertension derived equal benefits from use of combination therapy with a calcium antagonist and angiotensin-converting enzyme (ACE) inhibitor as from doubling the dose of the calcium antagonist. After a 2-week washout and a 2-week single-blind placebo run-in period, a total of 1,390 patients were treated with either nifedipine 30 mg (study 1) or amlodipine 5 mg (study 2) once daily for 4 weeks. The 1,079 patients whose diastolic blood pressure remained between 95 and 115 mm Hg were randomized to 8 weeks of double-blind therapy with amlodipine 5 mg/benazepril 10 mg, amlodipine 5 mg/ benazepril 20 mg, nifedipine 30 mg or nifedipine 60 mg (study 1), and amlodipine 5 mg/benazepril 10 mg, amlodipine 5 mg/benazepril 20 mg, amlodipine 5 mg or amlodipine 10 mg (study 2). Both doses of the calcium antagonist/ACE inhibitor combination therapy lowered diastolic pressure as much as the high dose and significantly better than the lower dose of calcium antagonist monotherapy (with either nifedipine or amlodipine). However, 15% of patients in the nifedipine high-dose monotherapy group and 24% in the amlodipine high-dose monotherapy group presented with some form of edema. In contrast, the incidence of edema was similar for patients treated with both combination therapy and low-dose calcium antagonists. Thus, combination therapy with a calcium antagonist and an ACE inhibitor provides blood pressure control equal to that of high-dose calcium antagonist monotherapy but with significantly fewer dose-dependent adverse experiences such as vasodilatory edema. Inc.

Adolescent↗
PubMed2000

Construction of transgenic mice with tissue-specific acceleration of mitochondrial DNA mutagenesis.

Transgenic mice having rapid accumulation of mitochondrial DNA (mtDNA) mutations specifically in the heart were created. These mice contained a transgene encoding a proofreading-deficient, mouse mitochondrial DNA polymerase (pol gamma) driven by the promoter for the cardiac-specific alpha-myosin heavy chain. Starting shortly after birth greater than 95% of all pol gamma mRNA in the heart was transgene derived; expression in other tissues was low or absent. Mutations in cardiac mtDNA began to accumulate by 7 days after birth. At 1 month of age the frequency of point mutations was 0.014% as determined by DNA sequencing of cloned mtDNA. By long-extension PCR multiple different deletion mutations that had removed several thousand basepairs of genomic sequence were also detected. Sequencing of two deletion molecules showed that one was flanked at the breakpoint by direct repeat sequences. The expression of proofreading-deficient pol gamma had no apparent deleterious effect on mitochondrial DNA and protein content, gene expression, or respiratory function. However, associated with the rise in mtDNA mutation levels was the development of cardiomyopathy as evidenced by enlarged hearts in the transgenic mice. These mice may prove to be useful models to study the pathogenic effects of elevated levels of mitochondrial DNA mutations in specific tissues.

Animals↗
PubMed2000

An intervention study on screening for breast cancer among single african-american women aged 65 and older.

PURPOSE: Older single African-American women are the population that is least likely to use screening procedures because of cognition-related, income-related, social-support-related and medical care-related barriers. This study aims to evaluate a breast screening intervention program developed according to socioeconomic, cultural, psychological and behavioral characteristics of older single African-American women.METHODS: Ten public housing complexes were randomly assigned to either intervention or control group. African-American women aged 65 and over were recruited into the study if they were widowed, divorced, separated or never-married in the preceding year, and did not have a history of breast cancer (n = 325). Delivered by lay health educators, the intervention program targeted increasing knowledge on breast health and breast screening, reducing emotional or psychological problems, and increasing support from the significant others of study women. Breast screening-related cognition and behavior were measured at pre-intervention and post-intervention.RESULTS: Comparisons of the pre-intervention and post-intervention measurements showed that while the proportion of women who had a clinical breast examination or mammogram in the preceding year was decreased at the post-intervention in the control group, it was increased in the intervention group. However, the differences did not reach a significant level. No consistent patterns could be found in changes of variables in knowledge, attitudes and beliefs. These results remained similar when potential confounding factors were adjusted using mixed model regression analyses.CONCLUSIONS: These results did not suggest significant effects of an intervention program which used lay health educators to promote breast cancer screening in older single African-American women.

Journal Article↗
PubMed2000

Urinary and sexual function after radical prostatectomy for clinically localized prostate cancer: the Prostate Cancer Outcomes Study.

CONTEXT: Patients with prostate cancer and their physicians need knowledge of treatment options and their potential complications, but limited data on complications are available in unselected population-based cohorts of patients. OBJECTIVE: To measure changes in urinary and sexual function in men who have undergone radical prostatectomy for clinically localized prostate cancer. DESIGN: The Prostate Cancer Outcomes Study, a population-based longitudinal cohort study with up to 24 months of follow-up. SETTING: Population-based cancer registries in 6 geographic regions of the United States. PARTICIPANTS: A total of 1291 black, white, and Hispanic men aged 39 to 79 years who were diagnosed as having primary prostate cancer between October 1, 1994, and October 31, 1995, and who underwent radical prostatectomy within 6 months of diagnosis for clinically localized disease. MAIN OUTCOME MEASURES: Distribution of and change in urinary and sexual function measures reported by patients at baseline and 6, 12, and 24 months after diagnosis. RESULTS: At 18 or more months following radical prostatectomy, 8.4% of men were incontinent and 59.9% were impotent. Among men who were potent before surgery, the proportion of men reporting impotence at 18 or more months after surgery varied according to whether the procedure was nerve sparing (65.6% of non-nerve-sparing, 58.6% of unilateral, and 56.0% of bilateral nerve-sparing). At 18 or more months after surgery, 41.9% reported that their sexual performance was a moderate-to-large problem. Both sexual and urinary function varied by age (39.0% of men aged <60 years vs 15.3 %-21.7% of older men were potent at > or =18 months [P<.001]; 13.8% of men aged 75-79 years vs 0.7%-3.6% of younger men experienced the highest level of incontinence at > or =18 months [P = .03]), and sexual function also varied by race (38.4% of black men reported firm erections at > or =18 months vs 25.9% of Hispanic and 21.3% of white men; P = .001). CONCLUSIONS: Our study suggests that radical prostatectomy is associated with significant erectile dysfunction and some decline in urinary function. These results may be particularly helpful to community-based physicians and their patients with prostate cancer who face difficult treatment decisions.

Adult↗
PubMed2000

The Protein Data Bank.

The Protein Data Bank (PDB; http://www.rcsb.org/pdb/ ) is the single worldwide archive of structural data of biological macromolecules. This paper describes the goals of the PDB, the systems in place for data deposition and access, how to obtain further information, and near-term plans for the future development of the resource.

Databases, Factual↗
PubMed2000

A randomized trial of a tailored, self-help dietary intervention: the Puget Sound Eating Patterns study.

BACKGROUND: This study evaluated a tailored, multiple-component self-help intervention designed to promote lower fat and higher fruit and vegetable consumption. METHODS: Participants were 1,459 adults selected at random, stratified by sex and age (18-34, 35-54, 55-69), from enrollees of a large health maintenance organization. After completing a baseline telephone survey, participants were randomized to receive the intervention (consisting of a computer-generated personalized letter, a motivational phone call, a self-help manual, a package of supplementary materials, computer-generated behavioral feedback based on a self-administered food frequency questionnaire, and newsletters) or to receive no materials. Evaluation was based on 1,205 (86.5%) participants who completed both a 3- and a 12-month follow up survey. RESULTS: The intervention effect +/- SE for fat, based on a diet habits questionnaire, was -0.10 +/- 0.02 (P < 0.001), corresponding to a reduction of approximately 0.8 percentage points of percentage energy from fat. For fruits and vegetables, the intervention effect was 0.47 +/- 0.10 servings/day (P < 0.001). Intervention effects were similar across age and sex groups. CONCLUSIONS: Tailored, self-help interventions can effectively promote dietary change among both men and women and among younger as well as older adults.

Adolescent↗
PubMed2000

The role of participation in the women's health trial: feasibility study in minority populations.

BACKGROUND: This paper examines participation rates and the association between participation and study outcomes (% energy from fat) among participants in the Women's Health Trial: Feasibility Study in Minority Populations, a randomized clinical trial to determine if ethnically and socioeconomically diverse women could be recruited and make significant dietary changes. METHODS: Women (n = 2,208) were recruited from three clinical centers and randomized to either an intervention group or a control group. Multiple measures were collected at 6 months. RESULTS: Participation rates for follow-up data collection activities were high (average participation 79%). Hispanics and lower educational groups participated significantly less (59% for Hispanics vs 86% for blacks and whites; 78% for lowest educational group vs 84% for highest educational group). Intervention participation significantly predicted change in percentage energy from fat (P < 0.001), accounting for an additional 8% of variance after background variables were controlled for. CONCLUSIONS: These data suggest that intervention participation is positively related to dietary change, but they cannot rule out the possibility that other factors may influence both of these factors.

Black or African American↗
PubMed2000

A model for tuberculosis with exogenous reinfection.

Following primary tuberculosis (TB) infection, only approximately 10% of individuals develop active T.B. Most people are assumed to mount an effective immune response to the initial infection that limits proliferation of the bacilli and leads to long-lasting partial immunity both to further infection and to reactivation of latent bacilli remaining from the original infection. Infected individuals may develop active TB as a consequence of exogenous reinfection, i.e., acquiring a new infection from another infectious individual. Our results in this paper suggest that exogenous reinfection has a drastic effect on the qualitative dynamics of TB. The incorporation of exogenous reinfection into our TB model allows the possibility of a subcritical bifurcation at the critical value of the basic reproductive number R(0)=1, and hence the existence of multiple endemic equilibria for R(0)<1 and the exogenous reinfection rate larger than a threshold. Our results suggest that reducing R(0) to be smaller than one may not be sufficient to eradicate the disease. An additional reduction in reinfection rate may be required. These results may also partially explain the recently observed resurgence of TB.

Disease Susceptibility↗
PubMed2000

Effect of polypeptide CH50 on macrophage activation in vivo and anti-tumor function.

The main features of CH50, a recombinant polypeptide of human fibronectin, activating macrophages in vivo and its anti-tumor function were investigated. After injection of CH50 and(or) transfection of IFN-gamma gene in vivo, several kinds of factors produced by macrophages were determined and the growth of tumor in vivo was measured. CH50 could enhance the production of such factors as NO, TNF and IL-1 by macrophages, but the activation of macrophages was relatively slow when CH50 was used in vivo alone. CH50 and IFN-gamma could synergistically activate macrophages rapidly in vivo no matter whether the injection of CH50 or the transfection of IFN-gamma gene was performed first. Injection of CH50 alone inhibited the formation of tumor nodes in a dose-dependent manner. Low dose of CH50 could strongly inhibit the formation of tumor nodes less than 1 mm, while high dose of CH50 could inhibit those more than 1 mm. A stronger inhibition on the growth of tumor in vivo was obtained by the synergistic effect of CH50 and IFN-gamma. CH50 and IFN-gamma, as double-signal factors for activation of macrophages, will be potentially useful in tumortherapy.

Animals↗
PubMed2000

Construction of eukaryotic expressing vector pCH503 of CH50 and its chemotaxis and anti-tumor function by expression in vivo in mice.

An eukaryotic expressing vector that expresses CH50, a recombinant polypeptide of human fibronectin, in mice was constructed, and its chemotactic and anti-tumor function by in vivo gene transfection was investigated. The plasmid was constructed by recombination techniques. The cDNA fragment coding CH50 polypeptide from a prokaryotic expressing vector of CH50 was ligated with 5'-terminal noncoding region and coding region of signal peptide of mouse IFN-gamma cDNA at 5' side and 3'-terminal noncoden region of human FN cDNA at 3' side. The recombinant cDNA was inserted into plasmid pREP8. The resulted expressing plasmid was designated as pCH503. The macrophages transfected with pCH503 in vivo and cultured in vitro could produce CH50. The expressed product was identified by heparin-affinity chromatography and SDS-PAGE. By counting and Giemsa-staining of coeliac cells and histotomy and staining of muscle tissue, the chemotaxis on immune cells was observed after transfection of pCH503 either in peritoneal cavity or in muscle. The inhibition of gene transfection of pCH503 on melanoma was observed in mice. The number of melanoma nodes in mice was reduced by 50%-60% after coeliac transfection with pCH503. The pCH503, an eukaryotic expressing vector of CH50, can express in vivo in mice. The transfection of pCH503 in vivo has the chemotaxis on immune cells and can inhibit the formation of tumor nodes, suggesting that plasmid pCH503 is potentially useful in combined treatment of tumor.

Animals↗
PubMed2000

Augmentation of recombinant CH50 polypeptide on the function of macrophages of mice during chemotherapy.

The immunosuppressive model of mice was made by intraperitoneal injection of cyclophosphamide. The effect of CH50, a recombinant polypeptide of human fibronectin, on macrophages of mice was observed. The results showed that continuous intraperitoneal injection of CH50 could prevent the reduction of the number of monocytes in periphery blood and abdominal cavity by chemotherapeutic agents, enhance the metabolic activity and cytotoxicity of macrophages and augment the proliferation of splenocytes. The results suggested that CH50 is a product which could be used to improve the efficacy of chemotherapy of tumors.

Adjuvants, Immunologic↗
PubMed2000

The role of cyclooxygenase 2 in ulcerative colitis-associated neoplasia.

Cyclooxygenase 2 (COX-2) overexpression has been described in sporadic colonic neoplasia, but its role in ulcerative colitis (UC) neoplastic progression remains unexplored. Although the specific role of cyclooxygenase in colonic neoplasia is uncertain, its inhibition by nonsteroidal anti-inflammatory drugs decreases the risk of sporadic colonic adenocarcinoma and causes regression of adenomas in familial adenomatous polyposis. To investigate the role of COX-2 in UC-associated neoplasia, we assessed COX-2 protein and mRNA expression throughout the spectrum of UC-associated neoplastic lesions in four total colectomy specimens, using immunocytochemistry and a novel TaqMan reverse transcriptase-polymerase chain reaction assay. The findings were correlated with DNA ploidy and inflammatory activity. We found COX-2 overexpression throughout the neoplastic spectrum in UC (P: < 0.0001, R:(2)=0.53), even in diploid samples that were negative for dysplasia. Overall, neoplastic change explained 53% of the variation in COX-2 expression, whereas inflammatory activity explained only 11%. COX-2 was overexpressed in all aneuploid samples and in 38% of diploid samples (P: = 0.0074). cDNA representational difference analysis was also performed and revealed that COX-2 mRNA was an up-regulated cDNA representational difference analysis difference product. COX-2 overexpression occurs early in UC-associated neoplasia, and the increase cannot be explained by inflammatory activity alone. The data suggest that COX-2-specific inhibitors may have a chemopreventative role in UC but the possibility that they could exacerbate UC inflammatory activity needs to be tested.

Adenocarcinoma↗