Biomedical subjects

Wei Zhou

Publications and source records attributed to Wei Zhou.

At least 235 records · Page 13Linked to original sources

PubMed2002

[Immunocontraceptive effect of a synthetic chimeric peptide of sperm].

OBJECTIVE: To investigate the immunocontraceptive ability of a new synthetic chimeric peptide with 35 amino acid residues. METHODS: A chimeric peptide with 35 amino acid residues was synthesized based on the amino acid sequence of SP17, a protein specific to murine testis/sperm, and cyritestin. The purified product, with keyhole limpet hemocyanin (KLH), was injected subcutaneously into the pad of female and male Balh/C mice. Blood was extracted from the ophthalmic arteries of the mice to identify the corresponding proteins from organs of mice and/or rat and human being by Western blotting. The chimeric peptide was injected into other female mice that were then raised together with male mice in the same cages to observe their status of pregnancy. Freund' adjuvant or normal saline were injected into the controls. RESULTS: The purity of the new chemiric peptide was 95%. The highest specific IgG titre in mouse serum was 1:6000 and the highest titre of specific IgA in the washing of vaginal mucous membrane of female mice was 1:300. The specific antiserum from the mice immunized by the chimeric peptide and KLH could identify two proteins with the molecular weights of 22 000 and 55 000 from testes of mice, rats, and human being. Western blotting showed no band for the extracts of mouse liver, spleen, and kidney. The pregnancy rate of female immunized mice was 61.11%, significantly lower that those in the controls (P < 0.05). The average number of cubs in a litter was less in the experimental group than in the controls (P < 0.05). CONCLUSION: The new chimeric peptide with 35 amino acid residues stimulates powerfully humoral and mucous immunity in mice and obviously decreases the pregnancy rate and the number of cubs in each litter in mice.

Animals↗

PubMed2002

High-order photobleaching of green fluorescent protein inside live cells in two-photon excitation microscopy.

Combination of green fluorescent protein (GFP) and two-photon excitation fluorescence microscopy (TPE) has been used increasingly to study dynamic biochemical events within living cells, sometimes even in vivo. However, the high photon flux required in TPE may lead to higher-order photobleaching within the focal volume, which would introduce misinterpretation about the fine biochemical events. Here we first studied the high-order photobleaching rate of GFP inside live cells by measuring the dependence of the photobleaching rate on the excitation power. The photobleaching rate under one- and two-photon excitation increased with 1-power and 4-power of the incident intensity, respectively, implying the excitation photons might interact with excited fluorophore molecules and increase the probability of photobleaching. These results suggest that in applications where two-photon imaging of GFP is used to study dynamic molecular process, photobleaching may ruin the imaging results and attention should be paid in interpreting the imaging results.

Diagnostic Imaging↗

PubMed2002

Gene-environment interaction for the ERCC2 polymorphisms and cumulative cigarette smoking exposure in lung cancer.

Excision repair cross-complementing group 2 (ERCC2), a major DNA repair protein, is involved in nucleotide excision repair and basal transcription. The ERCC2 polymorphisms have been associated with altered DNA repair capacity. We investigated two ERCC2 polymorphisms, Asp312Asn and Lys751Gln, in 1092 Caucasian lung cancer patients and 1240 spouse and friend controls. The results were analyzed using generalized additive models and logistic regression, adjusting for relevant covariates. The overall adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were 1.47 (95% CI, 1.1-2.0) for the Asp312Asn polymorphism (Asn/Asn versus Asp/Asp) and 1.06 (95% CI, 0.8-1.4) for the Lys751Gln polymorphism (Gln/Gln versus Lys/Lys). Gene-smoking interaction analyses revealed that the adjusted ORs for each of the two polymorphisms decreased significantly as pack-years increased. When comparing individuals with Asn/Asn + Gln/Gln versus individuals with Asp/Asp + Lys/Lys, the fitted ORs (95% CIs) were 2.56 (95% CI, 1.3-5.0) in nonsmokers and 0.69 (95% CI, 0.4-1.2) in heavy smokers (80 pack-years; P < 0.01 for the interaction term). Consistent and robust results were found when models incorporated different definitions of cumulative cigarette smoking. A stronger gene-smoking interaction was observed for the Asp312Asn polymorphism than for the Lys751Gln polymorphism. In conclusion, cumulative cigarette smoking modifies the associations between ERCC2 polymorphisms and lung cancer risk.

Adult↗

PubMed2002

Counting alleles to predict recurrence of early-stage colorectal cancers.

BACKGROUND: Chromosome imbalances occur in many cancers and represent important biological properties of tumours. However, measurements of such imbalances are difficult. We used a new, quantitative approach to investigate the prognostic value of chromosome imbalances in early-stage colorectal cancers. METHODS: We studied 180 patients with no evidence of lymph-node or distant metastases at the time of surgery. DNA from paraffin-embedded tumours was tested for imbalances of chromosome 8p and 18q by digital SNP (single-nucleotide polymorphism)-a technique in which each allele in a sample is directly counted. Surviving patients had median follow-up of 68 months, and disease recurrence was used as the clinical endpoint. FINDINGS: Tumours were divided into three groups: "L" tumours (n=93) had allelic imbalances of chromosomes 8p and 18q, "L/R" tumours (n=60) had allelic imbalances of either chromosome 8p or 18q but not both, and "R" tumours (n=27) retained allelic balance for both chromosomes. 5-year disease-free survival was 100% (95% CI 80-100) for patients with R tumours, 74% (61-87) for patients with L/R tumours, and 58% (47-69) for those with L tumours. These differences were significant (p<0.0001) and were independent of other variables--eg, Duke's stage A tumours of class L were much more likely to recur than Duke's stage B tumours of class R (p=0.002). INTERPRETATION: In patients without metastasis, allelic imbalance is a better predictor of prognosis than histopathological stage.

Aged↗

PubMed2002

Utility of the WHO neurobehavioral core test battery in Chinese workers-a meta-analysis.

We performed a meta-analysis to determine the most sensitive subtests of the WHO Neurobehavioral Core Test Battery (NCTB) when administered to Chinese workers. Extensive Chinese Biological Medical Database and MEDLINE searches, review of cited references, and discussion with other investigators were undertaken. Data were extracted from 39 eligible studies; the summary effects (effect sizes) were calculated using a fixed-effect model. Various exposure agents showed different sensitivities to the seven subtests of NCTB. For mercury-exposure, the Benton Visual Retention was the most sensitive subtest, with an effect size (95% CI) of 6.0 (4.4-7.6). For lead-exposure, the most sensitive subtests were the Pursuit Aiming II and Profile of Mood States, with effect sizes (95% CI) of 11.3 (8.3-14.3) and 10.6 (7.5-13.7), respectively. For organic solvents-exposure, Digit Span, Pursuit Aiming II, and Digit Symbol were the most sensitive subtests, with effect sizes (95- CI) of 4.7 (3.3-6.1), 4.6 (3.1-6.1), and 4.1 (2.7-5.5), respectively.

China↗

PubMed2002

Expression of PrP(C) as HIS-fusion form in a baculovirus system and conversion of expressed PrP-sen to PrP-res in a cell-free system.

Conversion of the PrP cellular form (PrP(C)) to the pathogenic form (PrP(Sc)) is the key step in the pathogenesis of transmissible spongiform encephalophathies. Although the mechanism of conformational conversion of PrP proteins remains uncertain, the cell-free conversion reaction and other in vitro PrP amplification tests allow it to be studied under the much quicker and simpler conditions than those of transmission bioassay in vivo. Using baculovirus expression system, wild-type hamster (HaPrP) and human PrP (HuPrP), as well as D178N mutated human PrP (HuPrPm178) were expressed in HIS-fusion form. After 35S-methionine labeling and purification with Ni-NTA agarose affinity chromatography, individual expressed PrP proteins were mixed with PrP(Sc) isolated from hamster brain tissue infected with scrapie 263K. Protease-resistant isoform was detected in the homologous HaPrP reaction, but not in the two heterologous HuPrP preparations, implying a species-specific molecular recognition between PrP(C) and PrP(Sc). HIS-tag in HIS-HaPrP seems to have little effect on the formation of protease-resistant protein in this preparation. This system proposes a simple and protein productive-enriched way for cell-free conversion of prion proteins, as the replacement of native or genetic engineering expressed sole PrP(C) from mammalian or non-mammalian sources.

Animals↗

PubMed2002

Inducer-stimulated Fas targets activated endothelium for destruction by anti-angiogenic thrombospondin-1 and pigment epithelium-derived factor.

Natural inhibitors of angiogenesis are able to block pathological neovascularization without harming the preexisting vasculature. Here we show that two such inhibitors, thrombospondin-1 and pigment epithelium-derived factor, derive specificity for remodeling vessels from their dependence on Fas/Fas ligand (FasL)-mediated apoptosis to block angiogenesis. Both inhibitors upregulated FasL on endothelial cells. Expression of the essential partner of FasL, Fas/CD95 receptor, was low on quiescent endothelial cells and vessels but greatly enhanced by inducers of angiogenesis, thereby specifically sensitizing the stimulated cells to apoptosis by inhibitor-generated FasL. The anti-angiogenic activity of thrombospondin-1 and pigment epithelium-derived factor both in vitro and in vivo was dependent on this dual induction of Fas and FasL and the resulting apoptosis. This example of cooperation between pro- and anti-angiogenic factors in the inhibition of angiogenesis provides one explanation for the ability of inhibitors to select remodeling capillaries for destruction.

Animals↗

PubMed2002

Mimovirus: a novel form of vaccine that induces hepatitis B virus-specific cytotoxic T-lymphocyte responses in vivo.

CD8(+) cytotoxic T lymphocytes (CTLs) are now recognized as important mediators of immunity against intracellular pathogens, including human immunodeficiency virus and tumors. How to efficiently evoke antigen-specific CTL responses in vivo has become a crucial problem in the development of modern vaccines. Here, we developed a completely novel CTL vaccine-mimovirus, which is a kind of virus-size particulate antigen delivery system. It was formed by the self-assembly of a cationic peptide containing 18 lysines and a CTL-epitope peptide of HBsAg(28-39), with a plasmid encoding mouse interleukin-12 (IL-12) through electrostatic interactions. We examined the formation of mimovirus by DNA retardation assay, DNase I protection assay, and transmission electron microscopy and demonstrated that mimovirus could efficiently transfer the plasmid encoding IL-12 into mammalian cells such as P815 cells in vitro. Furthermore, it was proved that mimovirus could induce an HBsAg(28-39)-specific CTL response in vivo. Considering its effectiveness, flexibility, and defined composition, mimovirus is potentially a novel system for vaccination against intracellular pathogens and tumors.

Animals↗

PubMed2002

Genetic polymorphisms in N-acetyltransferase-2 and microsomal epoxide hydrolase, cumulative cigarette smoking, and lung cancer.

N-acetyltrasferase-2 (NAT2) and microsomal epoxide hydrolase (mEH) are polymorphic genes that metabolize different tobacco carcinogens. Smaller studies found inconsistent relationships between NAT2 or mEH polymorphisms and lung cancer risk. To determine whether there is gene-environment interaction between NAT2 polymorphisms, alone or in combination with mEH polymorphisms, and cumulative smoking exposure in the development of lung cancer, we conducted a case control study of 1115 Caucasian lung cancer patients and 1250 spouse and friend controls. The results were analyzed using generalized additive models and logistic regression, adjusting for relevant covariates. There was no overall relationship between NAT2 genotype and lung cancer risk; the adjusted odds ratio (OR) of the rapid versus slow acetylator genotypes was 0.96 [95% confidence interval (CI), 0.79-1.16]. However, gene-environment interaction analyses revealed that the adjusted ORs increased significantly as pack-years increased. For nonsmokers, the fitted OR was 0.66 (95% CI, 0.44-0.99), whereas for heavy smokers (80 pack-years), the OR increased to 1.22 (95% CI, 0.89-1.67). When comparing the extreme genotype combinations of the NAT2 rapid acetylator, higher mEH activity genotype to the NAT2 slow acetylator, and very low mEH activity genotype, the corresponding ORs at 0 and 80 pack-years were 0.30 (95% CI, 0.14-0.62) and 2.19 (95% CI, 1.26-3.81), respectively. Results were similar with ORs derived from stratified models. In conclusion, NAT2 rapid acetylator genotypes are protective against lung cancer in nonsmokers but are risk factors in heavy smokers. The joint effects of NAT2 and mEH polymorphisms are consistent with an independent, additive effect of these two genes, modified by smoking history.

Adult↗

PubMed2002

[Establishment of a sandwich ELISA method for detection of reporter chloramphenicol acetyltransferase gene].

BACKGROUND: To establish a sandwich ELISA method for detection of reporter chloramphenicol acetyltransferase (CAT) gene. METHODS: The full length sequence of CAT gene was amplified with PCR using plasmid pBLCAT6 as template, and inserted into the prokaryotic expression plasmid Pgex-2T. The purified fusion protein was emulsified with complete or incomplete Freund adjuvant and injected subcutaneously into rabbits. The antibody was labeled with biotin, and a sandwich ELISA technique with biotin streptavidin amplify system was established. Several CAT reporter plasmids containing different HPV 16 LCR sequences were generated and transfected transiently to monolayer cells in vitro. The cytoplasm proteins were extracted and the expressions of CAT were evaluated with the newly established ELISA assay. RESULTS: SDS-PAGE displayed that the molecular weight of the expressed fusion protein was about 54,000. The prepared antiserum was able to recognize the CAT protein expressed by mammalian cells or prokaryote cells. Under the control of different promoters and their regulate sequences,two to eight folds CAT expression increased were evaluated in transiently transfected mammalian cells by the newly established sandwich ELISA method. CONCLUSIONS: The established method could sensitively reflect the activities of the upstream promoters, as well as the influence of exchanges of nucleotides within the regulate region on the promoter activities. Therefore, it proposes a convenient assay for the studies using CAT as the reporter gene.

Animals↗

PubMed2002

[A clinical study on clamp technique of intraocular lens on anterior capsule in cases with big rupture of posterior capsule of lens].

OBJECTIVE: To investigate the long-term results of the clamp technique of the posterior chamber intraocular lens (IOL) on the anterior capsule of lens in cases with big rupture of posterior capsule of lens. METHODS: The clamp technique of the posterior chamber IOL on the anterior capsule of lens were performed on 48 eyes of 48 cases with big rupture of the posterior capsule of lens following extracapsular cataract extraction for senile, traumatic, complicated and diabetic cataract. After 3-60 months follow-up, the vision acuity, position of IOL, capsular opacity and post-operative complications were investigated. RESULTS: The visual acuity of 39 eyes (81.3%) was >/= 0.5. The position of all IOL was in the optical center. The complications, such as after-cataract, retinal detachment, secondary glaucoma and persistent uveitis were not found. CONCLUSION: The clamp technique of the posterior chamber IOL on the anterior capsule of lens is convenient, safe and effectual in cases with big rupture of posterior capsule of lens.

Adult↗

PubMed2002

[Characteristics of polymorphism of 129th amino acid in PRNP among Han and Uighur Chinese].

BACKGROUND: An amino acid polymorphism for Met to Val has been identified at PrP codon 129 from different human races. In this study,the characteristics of polymorphism of PRNP 129th amino acid in Han and Uighur Chinese have been investigated. METHODS: Human DNAs were extracted from peripheral lymphocytes and PrP gene fragments were amplified with a specific PCR protocol. The distribution of 129th amino acid in PRNP was determined by a PCR-RFLP and the results were analyzed with software SAS for Windows 6.12. RESULTS: The frequencies of the allele 129 Met and 129 Val were 97.0% and 3.0% in Han Chinese, whereas 91.4% and 8.6% in Uighur Chinese. The frequency of 129 M/M phenotypes in Han Chinese was significantly higher than that in Uighur Chinese (P=0.0490). Comparing the phenotype distributions of codon 129 of Han Chinese with that of Japanese and Caucasian, there was significant difference with Caucasian (P=0.0005),but there was no difference with Japanese (P=0.5040). CONCLUSIONS: The polymorphism of 129th amino acid in PRNP of Han Chinese is similar to Japanese, but different from Uighur Chinese.

Asian People↗

PubMed2002

Counterpoint: the myeloperoxidase -463G-->a polymorphism does not decrease lung cancer susceptibility in Caucasians.

The myeloperoxidase (MPO) G-to-A substitution polymorphism in the promoter region of the MPO gene has been associated with a 40-70% reduction in lung cancer risk in several studies, although a recent nested case-control study disputes these findings. MPO is involved in the activation of a number of procarcinogens, including benzo(a)pyrene. The variant A allele has been shown to reduce MPO mRNA expression, thus potentially decreasing carcinogen activation. To confirm results from smaller studies, we evaluated this MPO polymorphism in 988 incident Caucasian lung cancer cases and 1128 controls. Logistic regression evaluated the association between MPO genotype and lung cancer risk, adjusting for age, gender, smoking status, time since quitting smoking, and pack-years of smoking. In the controls, the A allele frequency was 21%, and genotype distribution was in the Hardy-Weinberg equilibrium. Compared with the wild-type G/G genotype, the adjusted odds ratios for the A/A and A/G genotypes were 1.15 (95% confidence interval 0.7-1.9, P > 0.2) and 1.03 (95% confidence interval 0.8-1.3, P > 0.20), respectively. A similar lack of association was seen in analyses stratified by smoking status, median age, a number of smoking variables, disease stage, tumor grade, and histological subtype. These findings are in contrast with earlier studies suggesting a protective effect of carrying the variant A allele.

Adult↗

PubMed2002

[Effects of lead on NO, NOS, SOD, MDA in rat cerebral cortex].

UNLABELLED: To study the effects of lead exposure on nitric oxide (NO), nitric oxide synthase (NOS), super oxide dismutase (SOD) and malondialdehyde (MDA) in cerebral cortex of rats, Wistar rats are exposed to lead from drinking 0, 18.4, 184 mg/L lead acetate solution respectively. RESULTS: Cerebral cortex NOS activity in low and high-dosed lead exposure groups are significantly increased at the time of 7 days (P < 0.05), cerebral cortex NOS activity in low-dosed group is significantly decreased after 90 days and 30 days in high-dosed group (P < 0.05) as compared with that of the controls. Cerebral cortex NO content is markedly decreased in low-dosed group after 90 days poisoning and 14 days, 60 days, 90 days in high-dosed group (P < 0.05). SOD activity in low and high-dosed group is significantly decreased after 30 days exposure. MDA content is markedly increased after 14 days exposure in high-dosed group. CONCLUSION: It is suggested that the damage of cerebral cortex may caused by lead toxicity that results from the changes of NOS activity, NO level, SOD activity and MDA content in cerebral cortex.

Animals↗

PubMed2002

[Expression of human S100 protein and preparation of specific antiserum for S100 and establishment of a quantitative measurement for S100 protein in CSF specimens of patients with Creutzfeldt Jakob disease].

OBJECTIVE: To establish a method that can quantitatively detect S100 protein in CSF, and evaluate the possibility in diagnosis of Creutzfeldt-Jakob disease (CJD). METHODS: S100 gene was amplified by PCR from a commercially supplied human brain cDNA library. After verified by sequence analysis, the full length of S100 DNA was subcloned into a (GST) expression vector Pgex-2T, and the expression of GST-S100 fusion protein was induced. Rabbits were immunized with the purified GST-S100 fusion protein, and the antiserum raised against S100 protein was collected and further evaluated. Using biotin-avidin system, a sandwich ELISA was established for quantitatively determining S100 protein, and further, used in screening for S100 protein in CSF and serum samples. RESULTS: SDS-PAGE assays yielded a roughly 35,000 GST-S100 fusion protein. Using the established method, three CSF samples from probable CJD patients (14-3-3 protein positive in CSF) showed higher concentration of S100 protein (higher than 2.900 microg/L), whereas other CSF samples collected from patients with other CNS diseases showed lower concentration of S100 (less than 0.180 microg/L).Moreover, the sera S100 proteins from all the collected samples showed distinct individual difference. CONCLUSIONS: The established method can be used in determining S100 protein in CSF quantitatively. The feasibility and significance of S100 protein in CSF for diagnosis of CJD should be further considered with more CSF samples.

Animals↗

PubMed2002

[Studies of aroma components on essential oil of Chinese kushui rose].

The main chemical components of the rich peculiar aroma in the essential oil of Chinese Kushui rose (R. Setate x R. Rugosa) is reported. The differences in chemical components between Chinese Kushui rose oil and Bulgaria rose oil are compared. By OV1701 capillary column, more than 130 compounds were separated from the essential oil of Chinese Kushui rose. Using GC/MS and GC/IR techniques and some reference standards as the control, 101 compounds were tentatively identified from the separated compounds. This study shows that there are different aromas in rose essential oils. The oil of Chinese Kushui rose would be an important type of rose oil in the world due to its special rose aroma.

Acyclic Monoterpenes↗

PubMedDate not supplied

Coagulopathy review.

Explore the source record for details and available documents.

Journal Article↗

PubMedDate not supplied

Evaluation of the ELOVL4 gene in a Chinese family with autosomal dominant STGD3-like macular dystrophy.

Stargardt disease-3 (STGD3) is an autosomal dominant juvenile-onset macular dystrophy characterized by progressive decreasing visual acuity, bilateral atrophic changes in the macula and absence of characteristic dark choroids. We identified a STGD3-like macular dystrophy pedigree by clinical examination. To explore whether the STGD3-like phenotype in the kindred is linked to ELOVL4 gene or associated with any other identified STGD gene, we extracted genomic DNA from leukocytes of peripheral blood from the available family members and 50 normal controls for mutation analysis. Then the exons of ELOVL4, RDS and the three exons of ABCR were amplified by polymerase chain reaction (PCR). All PCR products were screened for mutations by combination of denaturing high-performance liquid chromatography (DHPLC) analysis and DNA sequencing. No mutation was found in the exons of three candidate genes, but we obtained three non-pathogenic polymorphisms, IVS5-2533T-->A in ELOVL4, 558C-->T (Val106Val) and 1150G-->C (Glu304Gln) in RDS. And IVS5-2533T-->A is never shown in the previous references. These data suggested that there exist other unknown genes responsible for the STGD3-like phenotype in the pedigree.

Angiography↗