Biomedical subjects

Ping Sun

Publications and source records attributed to Ping Sun.

At least 73 records · Page 4Linked to original sources

PubMed2005

Internet accessibility and usage among urban adolescents in Southern California: implications for web-based health research.

The World Wide Web (WWW) poses a distinct capability to offer interventions tailored to the individual's characteristics. To fine tune the tailoring process, studies are needed to explore how Internet accessibility and usage are related to demographic, psychosocial, behavioral, and other health related characteristics. This study was based on a cross-sectional survey conducted on 2373 7th grade students of various ethnic groups in Southern California. Measures of Internet use included Internet use at school or at home, Email use, chat-room use, and Internet favoring. Logistic regressions were conducted to assess the associations between Internet uses with selected demographic, psychosocial, behavioral variables and self-reported health statuses. The proportion of students who could access the Internet at school or home was 90% and 40%, separately. Nearly all (99%) of the respondents could access the Internet either at school or at home. Higher SES and Asian ethnicity were associated with higher internet use. Among those who could access the Internet and after adjusting for the selected demographic and psychosocial variables, depression was positively related with chat-room use and using the Internet longer than 1 hour per day at home, and hostility was positively related with Internet favoring (All ORs = 1.2 for +1 STD, p < 0.05). Less parental monitoring and more unsupervised time were positively related to email use, chat-room use, and at home Internet use (ORs for +1 STD ranged from 1.2 to 2.0, all p < 0.05), but not related to at school Internet use. Substance use was positively related to email use, chat-room use, and at home Internet use (OR for "used" vs. "not used" ranged from 1.2 to 4.0, p < 0.05). Self-reported health problems were associated with higher levels of Internet use at home but lower levels of Internet use at school. More physical activity was related to more email use (OR = 1.3 for +1 STD), chat room use (OR = 1.2 for +1 STD), and at school ever Internet use (OR = 1.2 for +1 STD, all p < 0.05). Body mass index was not related to any of the Internet use-related measures. In this ethnically diverse sample of Southern California 7(th) grade students, 99% could access the Internet at school and/or at home. This suggests that the Internet is already a potential venue for large scale health communication studies. Adolescents with more psychosocial risk factors or detrimental health behaviors were more likely to use the Internet. Therefore, if used properly, Internet interventions could effectively address the high risk populations. Additional research is needed to gain a more complete understanding of the positive and negative consequences of Internet use among adolescents.

Adolescent↗

PubMed2005

Gangliosides inhibit urokinase-type plasminogen activator (uPA)-dependent squamous carcinoma cell migration by preventing uPA receptor/alphabeta integrin/epidermal growth factor receptor interactions.

The interaction of the urokinase-type plasminogen activator (uPA) receptor (uPAR) with integrins plays a critical role in the regulation of cell adhesion and migration. However, the molecular events underlying the modulation of the interaction of uPAR and integrin are poorly understood. Gangliosides are thought to regulate epithelial cell adhesion and migration by inhibiting alpha(5)beta(1) integrin and epidermal growth factor receptor (EGFR) signaling. We report here that increases in the expression of ganglioside NeuAcalpha2-->3Galbeta1-->3GalNAcbeta1-->4(NeuAcalpha2-->8NeuAcalpha2-->3)Galbeta1-->4Glcbeta1-Cer (GT1b) or NeuAcalpha2-->3Galbeta1-->4Glcbeta1-Cer (GM3) inhibit uPA-dependent cell migration by preventing the association of uPAR with alpha(5)beta(1) integrin or uPAR/alpha(5)beta(1) integrin with the EGFR, respectively. As a result, uPA-dependent focal adhesion kinase (FAK) and integrin-mediated EGFR signaling are suppressed. Both gangliosides inhibit uPAR signaling-stimulated migration; however, GM3 inhibits uPA-induced EGFR phosphorylation by blocking the crosstalk between integrin and EGFR, whereas GT1b suppresses both uPA-induced FAK and EGFR activation by preventing the activation of integrin alpha(5)beta(1).

Carcinoma, Squamous Cell↗

PubMed2005

A comparison of bilateral breast cancers in BRCA carriers.

BACKGROUND: Women with breast cancer and a BRCA mutation have a high risk of developing a contralateral breast cancer. It is generally believed that the two cancers represent independent events. However, the extent of concordance between the first and second tumors with respect to hormone receptor expression and other pathologic features is unknown. PURPOSE: To determine the degree of concordance of estrogen receptor (ER) status, tumor grade, and histology in tumors from women with bilateral breast cancer and a BRCA mutation. SUBJECTS AND METHODS: Women with a history of bilateral invasive breast cancers were selected from an international registry of women with BRCA1 or BRCA2 mutations. Medical records were reviewed to document the characteristics of each cancer and the treatments received. RESULTS: Data were available for 286 women with bilateral breast cancer and a BRCA mutation (211 BRCA1; 75 BRCA2). The mean interval between first and second tumor was 5.1 years. The two tumors were concordant more often than expected for ER status (P < 0.0001) and for grade (P < 0.0001), but not for histology (P = 0.55). The ER status of the first tumor was highly predictive of the ER status of the second tumor (odds ratio, 8.7; 95% confidence interval, 3.5-21.5; P < 0.0001). Neither age, menopausal status, oophorectomy nor tamoxifen use was predictive of the ER status of the second tumor. CONCLUSIONS: There is strong concordance in ER status and tumor grade between independent primary breast tumors in women with a BRCA mutation. The excess concordance may be due to common risk factors, genetic variation, or the existence of a preneoplastic lesion that is common to both tumors.

Adult↗

PubMed2005

Crystallization and preliminary crystallographic analysis of human eukaryotic translation initiation factor 5A (eIF-5A).

Eukaryotic translation initiation factor 5A (eIF-5A) is universally found in all eukaryotic cells. It is the only protein in nature known to contain the unusual amino acid hypusine, a post-translationally modified lysine. Recombinant human eIF-5A was crystallized by the hanging-drop vapor diffusion method. Crystals were grown at 291 K using (NH4)2SO4 as precipitant. Diffraction data were obtained to a resolution of 2.7 A from a single frozen crystal belonging to space group C2, with unit-cell parameters a = 147.1 A, b = 60.4 A, c = 76.4 A, beta = 92.4 degrees. There are more than three molecules per asymmetric unit.

Crystallization↗

PubMed2005

An evaluation of the fidelity of implementation of a school-based drug abuse prevention program: project toward no drug abuse (TND).

This article provides an implementation fidelity evaluation of the fourth experimental trial of Project Towards No Drug Abuse (TND). Two theoretical content components of the curriculum were examined to increase our understanding of the active ingredients of successful drug abuse prevention programs. A total of 18 senior high schools were randomly assigned by block to receive one of three conditions: cognitive perception information curriculum, cognitive perception information + behavioral skills curriculum, or standard care (control). These curricula were delivered to both regular and continuation high schools students (n=2331) by trained project health educators and regular classroom teachers. Across all program schools, the two different curricula were implemented as intended, were received favorably by students, and showed significant improvements in knowledge specific to the theoretical content being delivered. This pattern of results suggests that the experimental manipulations worked as intended, and thus, permit the attribution of future behavioral outcome differences between conditions to differences in content of Project TND material provided rather than to differences in the fidelity of delivery. Further, our findings indicate that Project TND can be implemented effectively with low and high risk youth in a general environment as well as with high risk youth in a more specialized environment.

Adolescent↗

PubMed2005

Association between apolipoprotein A5 - 1131T > C polymorphism and susceptibility of coronary artery disease in Chinese.

OBJECTIVE: To investigate the relationship between apolipoprotein A5(apoA5) - 1131T > C polymorphism and the susceptibility of coronary artery disease (CAD) in Chinese. METHODS: The restriction fragment length polymorphism of apoA5 gene - 1131T > C was studied using PCR in a case-control study which enrolled 235 patients with CAD diagnosed by angiography and 262 healthy controls from Jiangsu province. RESULTS: The frequencies of T, C allele were 59.57%ì40.43% and 65.65%, 34.35% in CAD group and control group respectively. There was statistically significant difference in allele frequencies between CAD group and control group (P < 0.05). The susceptibility to CAD for the CC genotype was much higher than that for wild type TT (OR = 1.872, 95% CI = 1.039 - 3.376, P = 0.037), even after the use of Logistic regression models (OR = 2.285, 95% CI = 1.222 - 4.274, P = 0.012). In control group, there was significant difference in TG levels among different genotypes, the C allele carriers had higher serum TG concentration (P = 0.007). CONCLUSION: apoA5 - 1131T > C polymorphism is associated with an increased risk of CAD and is also in strong association with serum TG levels.

Aged↗

PubMed2005

[Study on the association of ABCA1 gene common variants with the risk of coronary atherosclerotic heart disease].

OBJECTIVE: To investigate the association of R219K and M883I polymorphisms of ATP binding cassette transporter 1 gene with lipid metabolism and the susceptibility to coronary atherosclerotic heart disease in Chinese population. METHODS: Genotypes were determined by PCR-restriction fragment length polymorphism and Primer introduced restriction analysis-PCR techniques, respectively, in 248 unrelated CHD-free controls and 224 CHD cases. RESULTS: Smoking, high blood pressure and high serum glucose were independent risk factors for CHD. Multivariate logistic regression analysis revealed that individuals carrying at least one 219K variant allele (RK + KK genotypes) had a significantly decreased risk for CHD (adjusted OR = 0.41; 95% CI = 0.27-0.61) compared with the wild-type genotype (219RR) and only 883II homozygotes displayed a decreased risk for CHD (adjusted OR = 0.54; 95% CI = 0.26-1.11) compared with 883MM and 883MI genotypes. Furthermore, compared with individuals with both wild genotypes (219 RR and 883 MM or 883 MI) other individuals with all other assembly genotypes had a significantly decreased risk (adjusted OR = 0.39, 95% CI = 0.26-0.60). Plasma HDL-C in 219K allele carriers were markedly higher than those in 219 K non-carriers in controls (P = 0.037). CONCLUSION: The ABCA1 R219K polymorphism may be involved in the variability of serum HDL-C and the susceptibility to coronary artery disease.

ATP Binding Cassette Transporter 1↗

PubMed2004

Method for reduction of background artifacts of images in scanning holography with a Fresnel-zone-plate coded aperture.

Near-infrared scanning holography with a Fresnel zone plate (FZP) coded aperture has potential applications in imaging through turbid media. However, the nonnegative intensity-distribution function of the FZP coded aperture introduces the background artifacts into the reconstructed images, reducing the contrast and the signal-to-noise ratio (SNR) of the images. A novel method termed as the composite hologram is proposed to reduce the artifacts. The computer simulations showed that the contrast and the SNR of the reconstructed images had improvements of at least 50.2% and 5.58-dB, respectively, compared with the conventional method. The composite hologram of a metal ring with a 6.0-mm diameter made by a wire with a 0.4-mm diameter immersing in 1% intralipid solution was recorded, and the reconstruction was performed numerically. The experimental results demonstrated that the contrast and the SNR of the reconstructed image had improvements of at least 32.3% and 2.51-dB, respectively.

Journal Article↗

PubMed2004

Smoking and the risk of breast cancer among carriers of BRCA mutations.

The effect of cigarette smoking on the risk of breast cancer is controversial, although most studies show little or no effect. It has been suggested that smoking may reduce the risk of developing hereditary breast cancer. We completed a case-control study on 1,097 women with breast cancer who were BRCA1 or BRCA2 mutation carriers and 1,097 age-matched controls with a mutation in the same gene but without breast cancer. There were no statistically significant differences between the cases and controls in terms of the number of current and ex-smokers (41.2% and 40.4%, respectively) or the age at smoking commencement (18.2 years and 18.5 years, respectively). There were no statistically significant differences between cases and controls regarding beginning smoking within 5 years of menarche (OR = 1.03; 95% CI 0.83 to l.28) or before the first pregnancy (OR = 1.09; 95% CI = 0.90 to 1.33). In conclusion, contrary to our previous report, smoking does not appear to be a risk factor for breast cancer among carriers of BRCA mutations.

Adolescent↗

PubMed2004

Contralateral breast cancer in BRCA1 and BRCA2 mutation carriers.

PURPOSE: To estimate the risk of contralateral breast cancer in BRCA1 and BRCA2 carriers after diagnosis and to determine which factors are predictive of the risk of a second primary breast cancer. PATIENTS AND METHODS: Patients included 491 women with stage I or stage II breast cancer, for whom a BRCA1 or BRCA2 mutation had been identified in the family. Patients were followed from the initial diagnosis of cancer until contralateral mastectomy, contralateral breast cancer, death, or last follow-up. RESULTS: The actuarial risk of contralateral breast cancer was 29.5% at 10 years. Factors that were predictive of a reduced risk were the presence of a BRCA2 mutation (v BRCA1 mutation; hazard ratio [HR], 0.73; 95% CI, 0.47 to 1.15); age 50 years or older at first diagnosis (v <or= 49 years; HR, 0.63; 95% CI, 0.36 to 1.10); use of tamoxifen (HR, 0.59; 95% CI, 0.35 to 1.01); and history of oophorectomy (HR, 0.44; 95% CI, 0.21 to 0.91). The effect of oophorectomy was particularly strong in women first diagnosed prior to age 49 years (HR, 0.24; 95% CI, 0.07 to 0.77). For women who did not have an oophorectomy or take tamoxifen, the 10-year risk of contralateral cancer was 43.4% for BRCA1 carriers and 34.6% for BRCA2 carriers. CONCLUSION: The risk of contralateral breast cancer in women with a BRCA mutation is approximately 40% at 10 years, and is reduced in women who take tamoxifen or who undergo an oophorectomy.

Adult↗

PubMed2004

Many-body approximation scheme beyond GW.

We explore the combination of the extended dynamical mean field theory (EDMFT) with the GW approximation (GWA); the former sums the local contributions to the self-energies to infinite order in closed form and the latter handles the nonlocal ones to lowest order. We investigate the different levels of self-consistency that can be implemented within this method by comparing to the exact quantum Monte Carlo solution of a finite-size model Hamiltonian. We find that using the EDMFT solution for the local self-energies as input to the GWA for the nonlocal self-energies gives the best result.

Journal Article↗

PubMed2004

Estrogen receptor status in BRCA1- and BRCA2-related breast cancer: the influence of age, grade, and histological type.

PURPOSE: BRCA1-related breast cancers are more frequently estrogen receptor (ER) negative than are either BRCA2-related or nonhereditary breast cancers. The relationship between ER status and other clinical features of hereditary breast cancers has not been well studied. EXPERIMENTAL DESIGN: ER status, grade, and histological tumor type were evaluated in 1131 women with invasive breast cancer, ascertained at 10 centers in North America. There were 208 BRCA1 mutation carriers, 88 BRCA2 carriers, and 804 women without a known mutation. We stratified the patients by mutation status, grade, age, and histological type and calculated the percentage of ER-positive tumors within each stratum. RESULTS: BRCA1 mutation carriers were more likely to have ER-negative breast cancers than were women in other groups, after adjustment for age, grade, and histological subtype (P < 0.001). Only 3.9% of BRCA1-related breast cancers were ER-positive cancers occurring in women in their postmenopausal years. The direction and magnitude of the change in ER status with increasing age at diagnosis in BRCA1 carriers was significantly different from in BRCA2 carriers (P(intercept) = 0.0002, P(slope) = 0.04). Notably, changes in ER status with age at diagnosis for BRCA1 carriers and noncarriers were almost identical (P(slope) = 0.98). CONCLUSIONS: The strong relationship between the presence of a BRCA1 mutation and the ER-negative status of the breast cancers is neither a consequence of the young age at onset nor the high grade but is an intrinsic property of BRCA1-related cancers. The ER-negative status of these cancers may reflect the cell of origin of BRCA1-related cancers.

Adult↗

PubMed2004

Acculturation, physical activity, and fast-food consumption among Asian-American and Hispanic adolescents.

Previous studies have implicated acculturation to the US as a risk factor for unhealthy behaviors among Hispanic and Asian-American adolescents, including substance use, violence, and unsafe sex. This study examined the association between acculturation and obesity-related behaviors-physical activity and fast-food consumption-among 619 Asian-American and 1385 Hispanic adolescents in Southern California. Respondents completed surveys in 6th and 7th grade. The 6th grade survey assessed acculturation with the AHIMSA acculturation scale and a measure of English language usage. The 7th grade survey assessed frequency of moderate-to-intense physical activity and frequency of eating fast-food. Multiple regression analyses included acculturation and demographic covariates as predictors of physical activity and fast-food consumption. Acculturation to the US, assessed in 6th grade, was significantly associated with a lower frequency of physical activity participation and a higher frequency of fast-food consumption in 7th grade. The significant associations persisted after controlling for covariates and were consistent across gender and ethnic groups. Results suggest that acculturation to the US is a risk factor for obesity-related behaviors among Asian-American and Hispanic adolescents. Health promotion programs are needed to encourage physical activity and healthy diets among adolescents in acculturating families.

Acculturation↗

PubMed2004

Cancer variation associated with the position of the mutation in the BRCA2 gene.

Inherited mutations of the BRCA2 gene give rise to a multi-site cancer phenotype which includes breast cancer (in female and males), ovarian, pancreatic and prostate cancer, ocular and other melanomas, laryngeal, colon and stomach cancers. Interpretation of test results and risk assessment is therefore complex. It has been proposed that families with mutations in the ovarian cancer cluster region (OCCR) of exon 11 (nucleotides 3035-6629) express a higher ratio of ovarian to breast cancer, than families with mutations elsewhere in the BRCA2 gene. In this study we have investigated the presence of 7 types of cancer (ovary, male breast, pancreas, prostate, colon, stomach and melanoma) in first- and second-degree relatives of mutation-positive individuals in 440 families with a BRCA2 mutation. We reviewed histories of cancer in relatives among families with mutations distributed throughout the gene. Families with ovarian cancer were more likely to harbour mutations in the OCCR (nucleotides 3035-6629) than elsewhere in the gene (OR = 2.21; P = 0.0002). We also compared cancer risks according to ethnic group. Ashkenazi Jewish families with the 6174delT founder mutation were more likely to have a family member with ovarian cancer (OR = 1.58; P = 0.002) and less likely to have a family member with prostate cancer (OR = 0.62; P = 0.04) than were non-Jewish families. In contrast, a reduced presence of ovarian cancer was found in families of French-Canadian ancestry, compared to other ancestries (OR = 0.37; P = 0.0026). A high risk of male breast cancer was observed with the 6503delTT mutation (OR = 15.7; P = 0.023). Families of Polish ancestry had a reduced frequency of pancreatic cancer (OR = 0.0; P = 0.03) compared to families of other ethnic origins. In conclusion, both the position of mutation and the ethnic background of the family appear to contribute to the phenotypic variation observed in families with BRCA2 mutations.

BRCA2 Protein↗

PubMed2004

Ultrasound/microbubble enhances foreign gene expression in ECV304 cells and murine myocardium.

Although viral vectors are efficient systems to transfer foreign genes into cells or target tissues, safety issues remain in relation to human gene therapy. Microbubbles currently used as ultrasound contrast agents have been applied in transfection of genes. This study was designed to test the transfection efficiency and the expression of exogenous gene mediated by ultrasound irradiation enhanced air filled albumin microbubbles in ECV304 cell line in vitro and the heart of the mouse in vivo. Air filled microbubbles (2.0-4.0 microm in diameter) were created by sonicating the mixture of human albumin, glucose, mannitol and special additive that was designed for stabilization. Plasmid DNA loading the reporter genes was gently mixed with microbubbles. The mixture of plasmid DNA and microbubbles was administrated to cultured ECV304 cells and BALB/c mice (tail vein injection) under different ultrasound/microbubble conditions, and then the transfection and expression efficiency were examined. The results both in vivo and in vitro demonstrated that microbubble with ultrasound irradiation could significantly elevate the exogenous gene expression as compared with microbubble or ultrasound only. Overall, the present study showed that the ultrasound-target microbubble destruction method enhanced the exogenous gene expression in vivo and in vitro, and provided a gene therapy way not only efficient but also easy to be manipulated and carried out in clinical.

Animals↗

PubMed2004

[Cloning and expression of a biotinylated multiple-epitope HCV fusion antigen gene].

The aim was to develop a single multiple-epitope fusion antigen which incorporates all of the major immunodominant epitopes from the six functional regions of the HCV genome. A nucleic acid sequence consisting of viral core, E1, E2, NS3, NS4, and NS5 regions was constructed and inserted into the Promega Pinpoint Xa-1 T vector for inducing expression. The protein was expressed in JM109 (DE3) as a fusion protein with a 13 kD biotinlated tag to be used for detection and affinity purification. Immunogenicity and biotinylated tag of the fusion protein were detected by Western blot analysis with positive anti-HCV serum and streptavidin alkaline phosphatase. After purified by Promega SoftLink Soft Release Avidin Resin, the protein was pre-coated on microwell and detected with anti-core, anti-NS3, anti-NS4 and anti-NS5 positive sera by EIA, respectively. The results indicated that the recombinant soluble protein was expressed and labelled with biotin successfully, it reacted with anti-HCV positive serum, and exposed all of the major immunogenic epitopes chosen. In conclusion, this recombinant antigen may be used to design an double antigen sandwich anti-HCV immunoassay.

Antigens, Viral↗

PubMed2004

[LC-MS analysis of three kinds of Mutong medicinal materials].

Three kinds of Mutong medicinal materials (Lardizabalaceae, Ranunculaceae, Aristolochiaceae) were analyzed qualitatively by LC-MS. The results show Mutong of Lardizabalaceae and Mutong of Ranunculaceae have more the same chemical constituents, and Mutong of Aristolochiaceae has less the same constituents with them. These results are consistent with their medicinal properties and explain the similarity and difference in medicinal properties from chemical basis.

Aristolochia↗

PubMed2003

Disruption of the expected positive correlation between breast tumor size and lymph node status in BRCA1-related breast carcinoma.

BACKGROUND: A positive correlation between breast tumor size and the number of axillary lymph nodes containing tumor is well established. It has been reported that patients with BRCA1-related breast carcinoma are more likely than patients with nonhereditary breast carcinoma to have negative lymph node status. Therefore, the authors questioned whether the known positive correlation between tumor size and lymph node status also was present in women with BRCA1-related breast carcinomas. METHODS: The relation between the greatest dimension of the resected breast tumor (size) and the presence of positive axillary lymph nodes (expressed as a percentage of all lymph nodes examined) was evaluated in 1555 women with invasive breast carcinoma who were ascertained at 10 centers in North America between 1975 and 1997. There were 276 BRCA1 mutation carriers, 136 BRCA2 carriers, and 1143 women without a known mutation (208 BRCA1/BRCA2 noncarriers and 935 untested women). Patients were stratified according to tumor size, and odds ratios were estimated for the presence of positive lymph nodes with increasing tumor size. RESULTS: A highly significant positive correlation between tumor size and the frequency of positive axillary lymph nodes was seen for BRCA1/BRCA2 noncarriers, for BRCA2 carriers, and for untested women (overall P < 0.0001 for each). In contrast, there was no clear correlation between tumor size and positive lymph node status in BRCA1 carriers (overall P = 0.20). CONCLUSIONS: The relation between tumor size and lymph node status in patients with breast carcinoma appears to be different in BRCA1 carriers compared with BRCA2 carriers and noncarriers. These findings have important implications for estimating the route of metastatic spread and for evaluating the effectiveness of early diagnosis in patients with BRCA1-related breast carcinoma.

Breast Neoplasms↗