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Biomedical subjects

Yan Sun

Publications and source records attributed to Yan Sun.

At least 91 records · Page 5Linked to original sources
PubMed2005

Cloning and overexpression of CYP6F1, a cytochrome P450 gene, from deltamethrin-resistant Culex pipiens pallens.

CYP6F1 (GenBank/EMBL accession No. AY662654), a novel gene with a complete encoding sequence in the cytochrome P450 family 6, was cloned and sequenced from deltamethrin-resistant 4th instar larvae of Culex pipiens pallens. The cDNA sequence of CYP6F1 has an open reading frame of 1527 bp, which encodes a putative protein of 508 amino acid residues. The deduced amino acid sequence of CYP6F1 indicated that the encoded P450 has conserved domains of a putative membrane-anchoring signal, putative reductase-binding sites, a typical heme-binding site, an ETLR motif and substrate recognition sites. Semi-quantitative RT-PCR analysis indicated that the CYP6F1 gene was expressed to a greater extent in the deltamethrin-resistant strain than in the susceptible strain of Cx. pipiens pallens. The expression levels of the CYP6F1 gene in the deltamethrin-resistant 1st, 2nd, 3rd, 4th instar larvae and adult female mosquitoes differed, with highest expression levels in the 4th instar larvae. In addition, the CYP6F1 gene was stably expressed in mosquito C6/36 cells, and the expected 61.2 kDa band was identified by Western blotting. The cells transfected with CYP6F1 had an increased resistance to deltamethrin as compared with control cells. These results indicate that CYP6F1 is expressed at higher levels in the deltamethrin-resistant strain, and may confer some insecticide resistance in Cx. pipiens pallens.

Amino Acid Sequence↗
PubMed2005

Effects of glucosinolate-rich broccoli sprouts on urinary levels of aflatoxin-DNA adducts and phenanthrene tetraols in a randomized clinical trial in He Zuo township, Qidong, People's Republic of China.

Residents of Qidong, People's Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of aflatoxin-contaminated foods, and are exposed to high levels of phenanthrene, a sentinel of hydrocarbon air toxics. Cruciferous vegetables, such as broccoli, contain anticarcinogens. Glucoraphanin, the principal glucosinolate in broccoli sprouts, can be hydrolyzed by gut microflora to sulforaphane, a potent inducer of carcinogen detoxication enzymes. In a randomized, placebo-controlled chemoprevention trial, we tested whether drinking hot water infusions of 3-day-old broccoli sprouts, containing defined concentrations of glucosinolates, could alter the disposition of aflatoxin and phenanthrene. Two hundred healthy adults drank infusions containing either 400 or < 3 micromol glucoraphanin nightly for 2 weeks. Adherence to the study protocol was outstanding; no problems with safety or tolerance were noted. Urinary levels of aflatoxin-N(7)-guanine were not different between the two intervention arms (P = 0.68). However, measurement of urinary levels of dithiocarbamates (sulforaphane metabolites) indicated striking interindividual differences in bioavailability. An inverse association was observed for excretion of dithiocarbamates and aflatoxin-DNA adducts (P = 0.002; R = 0.31) in individuals receiving broccoli sprout glucosinolates. Moreover, trans, anti-phenanthrene tetraol, a metabolite of the combustion product phenanthrene, was detected in urine of all participants and showed a robust inverse association with dithiocarbamate levels (P = 0.0001; R = 0.39), although again no overall difference between intervention arms was observed (P = 0.29). Understanding factors influencing glucosinolate hydrolysis and bioavailability will be required for optimal use of broccoli sprouts in human interventions.

Adult↗
PubMed2005

Activation of toll-like receptor (TLR)2, TLR4, and TLR9 in the mammalian cornea induces MyD88-dependent corneal inflammation.

PURPOSE: Toll-like receptors (TLRs), which recognize microbial products, have an important role in the host innate immune response. The purpose of the present study was to determine whether activation of these receptors leads to development of keratitis and to assess the role of the common adaptor molecule myeloid differentiation factor-88 (MyD88). METHODS: Corneal epithelium of C57BL/6, TLR2(-/-), TLR9(-/-), and MyD88(-/-) mice was abraded and treated with Pam(3)Cys, LPS, or CpG DNA, which bind TLR2, -4, and -9, respectively, and neutrophil recruitment to the corneal stroma, development of corneal haze, and chemokine production were measured. RESULTS: Activation of TLR2 and -9 stimulated neutrophil recruitment to the corneal stroma of C57BL/6 mice, but not TLR2(-/-) or -9(-/-) mice, respectively. In marked contrast, neutrophil migration to the corneal stroma of MyD88(-/-) mice challenged with Pam(3)Cys, LPS, or CpG DNA was completely ablated. Activation of TLR2, -4, and -9 also caused a significant increase in corneal thickness and haze, indicative of disruption of corneal clarity; however, this response was ablated in MyD88(-/-) mice, which were not significantly different from untreated corneas. Production of CXC chemokines MIP-2 and KC, which mediate neutrophil recruitment to the corneal stroma, was elevated in the corneal epithelium and stroma of control, but not MyD88(-/-) mice. CONCLUSIONS: Together, these findings demonstrate that the corneal epithelium has functional TLR2 and -9, and that TLR2, -4, and -9 signal through MyD88. This pathway is therefore likely to have an important role in the early events leading to microbial keratitis.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Phenotypic diversity of the lung vasculature in experimental models of metastases.

In vivo phage display is a screening method in which peptides homing to specific vascular beds are selected after IV administration of a random peptide library. This strategy has revealed a vascular address system that allows tissue-specific targeting of normal blood vessels and angiogenesis-related targeting of tumor blood vessels by selected peptides. Many vascular receptors or "addresses" targeted by homing peptides have been identified. One such vascular receptor of normal lung endothelium is membrane dipeptidase (MDP), which was found by in vivo phage display to bind the tripeptide motif gly-phe-glu (GFE). Our studies with GFE peptide and lung vasculature suggest that MDP mediates cancer cell adhesion to lung vasculature and the development of lung metastases, but that MDP is not present in the vasculature of lung metastases. MDP appears to occupy a vascular distribution that is similar to the pulmonary artery circulation. These results demonstrate the promise of defining critical functional and anatomic characteristics of endothelial cells in lung and other organs by in vivo phage display.

Animals↗
PubMed2005

[Effect of cyclosporine A on the trophoblast cell secretion of interleukin-10 and interferon-gamma in early pregnancy].

OBJECTIVE: To investigate the effect of cyclosporine A (CsA) on the trophoblast cell secretion of interleukin-10 (IL-10) and interferon-gamma (IFN-gamma) in early pregnancy. METHODS: The 6-8-week gestation trophoblasts were isolated, purified; digested by trypsin, cultured in vitro, and then were treated with CsA 0 micromol/L, 0.1 micromol/L, 1.0 micromol/L and 10.0 micromol/L respectively. The IL-10 and IFN-gamma were assayed by computerized image analysis techonology. The IL-10 and IFN-gamma mRNA expressions were determined by RT-PCR. RESULTS: CsA at 0.1 and 1 micromol/L obviously increased the secretion of protein IL-10 in trophoblast cell (P<0.05). However, the secretion of IL-10 was not affected when CsA was at 10 micromol/L (P>0.05). IFN-gamma protein expressed in the trophoblast membrane of cell in the CsA at 4 concentrations were almost the same; there was no significant difference among the 4 CsA concentrations (P>0.05). mRNA expressions were the same as the expressions defected by means of immunohistochemical staining. CONCLUSION: CsA can well control the secretion of cytokine of the trophoblast cell when CsA is in a range of suitable concentrations.

Adult↗
PubMed2005

[No evidence for genetic association between alpha-2 macroglobulin I1000V polymorphism and sporadic Alzheimer's disease in two independent Chinese populations].

OBJECTIVE: Alpha-2 macroglobulin (alpha2M) is a proteinase inhibitor found in association with senile plaques in Alzheimer's disease (AD). Also alpha2M has been implicated in several pathophysiological processes in AD. In view of the recent contradictory reports on the relationship between AD and a common polymorphism I1000V in A2M gene, the present authors studied a relatively large sample, determined the genotype of the I1000V polymorphism in A2M gene in sporadic AD patients and age-matched controls with normal cognition, and examined the possible association of the polymorphism with AD. METHODS: Genotypes of A2M and apolipoprotein E (apoE) were detected by polymerase chain reaction combined with restriction fragment length polymorphism in 257 patients and 242 controls in Guangzhou, and 112 patients and 113 controls in Chengdu. RESULTS: The 1000Val allele frequencies in the merged AD and control groups were 7.7% and 8.7%, respectively. The differences of allelic and genotypic frequencies between the patients and control subjects were not statistically significant, even after stratification by apoE epsilon4 status or by age-of-onset of the disease. CONCLUSION: The results of this study revealed no association between the I1000V polymorphism of A2M and Chinese sporadic AD in Guangzhou and Chengdu.

Aged↗
PubMed2005

[The C224T polymorphism in the cathepsin D gene is not associated with sporadic Alzheimer's disease in Chinese].

Cathepsin D is the major lysosomal/endosomal aspartic protease and exhibits beta- and gamma-secretase-like activity in vitro. Data from German suggest that the C224T polymorphism in the Cathepsin D gene (CTSD) exon 2 is strongly associated with the risk for Alzheimer's disease (AD). Meanwhile other studies have not been able to replicate the result. It's necessary to determine the genotype of the polymorphism in CTSD in Chinese sporadic AD patients and age-matched controls with normal cognition and examine possible association of the polymorphism with the disease. We find no strong evidence of association between the CTSD C224T polymorphism and Chinese sporadic AD. Whereas there may be a weak synergistic interaction between ApoE epsilon4 and CTSD T allele.

Aged↗
PubMed2005

[Progress on microbial glyceride biosynthesis and metabolic regulation in oleaginous microorganisms].

Oleaginous microorganisms are small portion of organisms that have ability to accumulate lipids over 20% of their biomass. These species can transform renewable material into microbial oil with similar fatty acid composition to that of plant-based oil. Some organisms may also produce glycerides with high content of poly-unsaturated fatty acids. Therefore, microbial lipids are considered as potential oil resource. Summarized here are some features of oleaginous species and recent developments on their biosynthetic machinery and metabolic regulation mechanism.

Fatty Acids, Unsaturated↗
PubMed2005

[Construction and immunological study of recombinant hBD-2/PSMA chimeric protein eukaryotic expressive plasmid].

The recombinant PSMA DNA vaccine for active immunotherapy of prostate cancer was investigated. Two DNA vaccine recombinant plasmids, pcDNA3.1/PSMA and pcDNA3.1/hBD-2-PSMA, were constructed by inserting the hBD-2 gene and PSMA gene into an eukarytoic expression vector pcDNA3.1. Expression of the two recombinants was detected in transfected COS-7 cells and inoculated mouse muscular cells by RT-PCR and immunohistochemical method. When immunized with pcDNA3.1/PSMA and pcDNA3.1/hBD-2-PSMA, the immunized BALB/c mice acquired specific antibody and T cell response to PSMA. The quantity of the spleen lymphocytes and their CTL activity against PSMA gene transfected-BALB/3T3 cells significantly increased in the immunized mice, and the CTL activity of lymphocytes from pcDNA3.1/hBD-2-PSMA immunized mice was significantly higher than that of pcDNA3.1/PSMA immunized mice. This result suggests that pcDNA3.1/hBD-2-PSMA would probably be developed as a DNA vaccine for the immunotherapy of prostate cancer.

3T3 Cells↗
PubMed2005

[Correlation of expression of connexin to growth and progression of cervical carcinoma in situ].

BACKGROUND & OBJECTIVE: Gap junction intercellular communication (GJIC), mediated by connexin (CX), is the unique type of intercellular communication in carcinoma in situ (CIS). Changes in expression of CXs and function of GJIC may play roles in carcinogenesis of cervical cancer and progression of CIS. This study was to investigate the expression of CXs in normal epithelium (NE), hyperplasia, CIS, and invasive carcinoma (IC) of cervix, to explore correlation of expression of CXs to pathogenesis and progression of cervical CIS. METHODS: Expression of CX43 (mRNA, protein), CX26 (mRNA), and Ki-67 (protein) in 30 specimens of cervical NE, 22 specimens of cervical hyperplasia, 30 specimens of cervical CIS, and 26 specimens of cervical IC were detected by immunohistochemistry and in situ hybridization. RESULTS: In cervical NE, hyperplasia, CIS, and IC, positive rates of CX43 protein were 83%, 55%, 50%, and 30%, respectively, and positive rates of CX43 mRNA were 97%, 64%, 58%, and 46%, respectively; positive rates of CX26 mRNA was 93%, 68%, 55%, and 42%, respectively. Positive rates of CX43 (mRNA, protein) and CX26 (mRNA) were gradually decreased. Positive rate of CX was significantly lower in CIS group than in NE group (P < 0.05). The expressions of CX26 and CX43 were weaker in CIS group than in NE groupu their expressions were obviously decreased, or even vanished in the area of CIS adjacent to NE. Proliferating index (PI), indicated by expression of Ki-67 protein, was increased gradually in NE (5%), hyperplasia (12%), CIS (30%), and IC (62%)u the differences were significant (P < 0.05) between CIS group and other groups. CONCLUSIONS: CX26 and CX43 may play important roles in carcinogenesis of cervical cancer. CXs may inhibit tumorigenesis and cell proliferation; it might be key factors in earlier stages when cellular malignant phenotypes have been established, or NE has been transformed into CIS.

Carcinoma in Situ↗
PubMed2005

[Charactierization of a new antibacterial polypeptide isolated from human cervical mucas].

OBJECTIVE: To identify a new antibactrial polypeptide HCP-1 isolated from human cervical mucus. METHODS: HCP-1 was isolated and purified from human cervical mucus, and N-terminal sequence of HCP-1 was determined. A degenerate primer was designed according to CodeHop methods, and an "anchor-oliga-dT primer" was used for the synthesis of cDNA. Using the degenerate primer and anchor-primer, cDNAs were amplified by PCR. The PCR products were cloned, sequenced, and analyzed by biological software. RESULTS: N-terminat sequence of HCP-1 was PKRKAEGDAK. The full length of HCP-1 cDNA was isolated and of which the sequence was the same as HMG-17. OMIGA software analysis indicated that this molecule contained an alpha-helix region. CONCLUSION: The new antibacterial polypeptide isolated from human cervical mucus is HMG-17. It may play a role in the human cervical mucus and the alpha-helix domain may be its antibacterial activity region.

Adult↗
PubMed2005

Screening for ZNF230 gene mutation and analysis of its correlation with azoospermia.

OBJECTIVE: To investigate the possible association between ZNF230 gene and azoospermia. METHODS: Screening for mutation of all 6 exons of ZNF230 gene was performed by denaturing high performance liquid chromatography(DHPLC) in 99 patients with azoospermia and in 115 healthy men as controls. RESULTS: An A-->G transition at nucleotide 316 in exon 6 was identified. There were significant differences in the distribution profiles of both allele and genotype frequencies between patient group and control group (P < 0.01 and P < 0.05, respectively). In addition,there was a statistically significant difference in the serum follicle stimulating hormone (FSH) level between the patients with GG/GA genotype and those with AA genotype (P < 0.05). CONCLUSION: ZNF230 gene may be associated with azoospermia, and the A316G mutation may be correlated with the serum FSH level.

Adult↗
PubMed2005

[Thyroid cartilage flap reconstruction of cricoid in the management of subglottic carcinoma].

OBJECTIVE: To evaluate the effect of conservative surgical management on patients with subglottic cancer. METHODS: Nine cases with subglottic carcinoma were treated surgically from 1984 to 1999. There were T2N0 lesions in 2 cases, T3N0-1 in 3 cases and T4N0-1 in 4 cases. All the cases underwent partial laryngectomy including partial cricoid resection. Variations of a pedicled thyroid cartilage flap were used for reconstruct the cricoid defect. The pedicle based muscle was thyrohyoid, sterno-thyroid or inferior constrictor. Unilateral neck dissection was performed on 7 cases and bilateral on two. RESULTS: The function of phonation were preserved in all cases. Eight of nine 8/9 were decanulated. Normal deglutition were achieved for all patients. The 3 and 5 year survival rates were 8/9 and 6/9, respectively. CONCLUSION: Pedicled thyroid cartilage flap is appropriate for reconstruction of the cricoid defect in the conservative surgery of selected subglottic carcinoma.

Adult↗
PubMed2005

[Analysis of prognosis of patients with decompensated liver cirrhosis using the criterion of the Model of End-Stage Liver Disease].

OBJECTIVE: To investigate the relationship between the Model for End-Stage Liver Disease (MELD) with Child-Pugh scoring, and the prognosis of patients with decompensated liver cirrhosis. METHODS: 110 patients with decompensated liver cirrhosis were graded with MELD formula and with Child-Pugh. The death rate was observed within three months. RESULTS: 31 patients died within 3-months. The mortality of patients whose MELD scores were between 10 approximately 19, 20 approximately 29, and > or = 30 was higher than those with MELD < or = 9 (The mortality of those with MELD less than 9, 10 approximately 19, 20 approximately 29, or > or = 30 was 11.76%, 38.18%, 64.71%, 75.00% respectively). The mortality of patients whose MELD scores were > or = 18 was higher than those with MELD < 18 (The mortality of those with MELD < 18, MELD > or = 18 was 26.58%, 58.06% respectively. chi2 = 9.643). The mortality of Child A, B, C was 14.89%, 42.55%, 75% respectively. CONCLUSION: Both MELD and Child-Pugh scores can accurately predict the short-term prognosis of patients with decompensated liver cirrhosis.

Aged↗
PubMed2005

[A study on the extraoral cervical traction in the treatment of skeletal Class II division 1 malocclusion in mixed dentition].

PURPOSE: To evaluate the effects of extraoral cervical traction on skeletal Class II division 1 malocclusion of early or late mixed dentition and discuss the optimal treatment timing. METHODS: The sample consisted of two groups of skeletal Class II division 1 malocclusion. One group with 11 cases was treated started in early mixed dentition while the other with 15 cases in late mixed dentition. All cases were treated with extraoral cervical traction headgear. Cephalometric analysis was conducted to evaluate the treatment effects. Student's t test was applied for statistical analysis. RESULTS: SNA, ANB and the length of maxilla (A-Ptm) were reduced and the inclination of maxillary incisor was decreased in both two groups. When comparing the two groups, it was found that the reduction of SNA was more notable, which means the inhibition of the maxilla was more evident in late mixed dentition. The difference was statistically significant (P<0.01). There was no significant difference on the distalization of the first upper molar between two groups (P<0.01). CONCLUSIONS: The extraoral cervical traction might be more effective in late mixed dentition to restrain maxillary growth in the treatment of skeletal Class II division 1 malocclusion.

Dentition, Mixed↗
PubMed2005

A novel mutation in the FOXL2 gene in a Chinese family with blepharophimosis, ptosis, and epicanthus inversus syndrome.

OBJECTIVE: To screen mutations in the forkhead transcriptional factor 2 gene (FOXL2) in six Chinese families with blepharophimosis, ptosis, and epicanthus inversus syndrome(BPES). METHODS: PCR amplification and direct sequencing of the FOXL2 coding region in genomic DNA were performed in affected patients and 80 healthy controls. BLAST analysis of the sequence was made on Internet. RESULTS: A novel 951-953(delC) was found in the two affected patients of a Chinese family with BPES. No mutations were found in the healthy controls. The 951-953(delC) may cause a frameshift mutation after codon 238 that exists downstream of the forkhead domain, resulting in the production of truncated proteins. CONCLUSION: These findings indicated that the 951-953(delC) deletion mutation in the two patients resulted in truncated proteins and hence led to their BPES. To the authors' knowledge, the 951-953(delC) in FOXL2 has not been previously reported.

Amino Acid Sequence↗
PubMed2005

[Transdermal fentanyl for the management of cancer pain: a survey of 4492 patients].

OBJECTIVE: To evaluate the efficacy and adverse effects of transdermal fentanyl in management of patients with cancer pain. METHODS: A total of 4492 patients (aged 3-90) with cancer pain were enrolled in this multicenter study. The mean age was 58.5 (3 approximately 90) years old. All patients received transdermal fentanyl. The patients were asked to record the attacks of pain, quality of life, and any side effects of the treatment. RESULTS: Baseline mean pain intensity was 7.37. On days 1, 3, 6, 9, 15, and 30, the mean scores of pain were decreased to 4.04, 2.98, 2.52, 2.19, 1.85 and 1.61, respectively (P < 0.01). The effective rate was 96.8%. The mean doses of fentanyl were 32.37 microg/h (25-200 microg/h) on the initial day, 42.57 microg/h and 49.57 microg/h (25-225 microg/h) on days 15 and 30. The quality of life was significantly improved after treatment (P < 0.01). The common side effects were constipation (9.8%), nausea (13.6%), dizziness (6.5%), vomiting (3.9%), sedation (2.0%) and respiratory depression (0.2%). The incidence of constipation was related to age, and the incidence of vomiting and difficulty of urination was related to gender. The majority (84.5%) of patients preferred continuation of the treatment with transdermal fentanyl. CONCLUSION: Transdermal fentanyl for the patients with cancer pain is effective, safe, convenient and can improve the quality of life. Transdermal fentanyl can be recommended as one of first-line drugs for the treatment of patients with moderate to severe cancer pain.

Administration, Cutaneous↗