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Biomedical subjects

Qing Zhang

Publications and source records attributed to Qing Zhang.

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

Are left ventricular diastolic function and diastolic asynchrony important determinants of response to cardiac resynchronization therapy?

Cardiac resynchronization therapy (CRT) has been shown to reduce symptoms and reverse left ventricular (LV) remodeling. It is not known, however, whether diastolic function will improve after CRT and diastolic asynchrony will predict LV reverse remodeling. Seventy-six patients (mean age 65 +/- 12 years, 74% men) who received CRT were studied at baseline and after 3 months. Diastolic function was assessed by transmitral Doppler and tissue Doppler imaging. LV systolic and diastolic asynchrony were assessed by the time to peak myocardial contraction (Ts) and early diastolic relaxation (Te) using the 6 basal, 6 mid-segmental model. There were 42 responders (55%) with LV reverse remodeling (defined as a reduction of LV end-systolic volume >or=15%). Parameters of systolic function were significantly improved only in the responders. For diastolic function, there were reductions of transmitral E velocity in the 2 groups, without any change in atrial velocity or the E/A ratio. Tissue Doppler imaging revealed that myocardial early diastolic velocity was unchanged in responders but was significantly worsened in nonresponders. The systolic asynchrony index (the SD of Ts of 12 LV segments) correlated significantly with LV reverse remodeling (r = -0.64, p <0.001) but not the diastolic asynchrony index (the SD of Te of 12 LV segments) (r = -0.10, p = NS). The systolic asynchrony index was the only independent predictor of reverse remodeling (beta = -0.99, 95% confidence interval -1.41 to -0.58, p <0.001). In conclusion, CRT improves systolic function and systolic asynchrony but has a neutral effect on diastolic function and diastolic asynchrony. LV reverse remodeling response is determined by the severity of prepacing systolic asynchrony but not diastolic asynchrony or the diastolic filling pattern.

Aged↗
PubMed2006

Chronic systemic D-galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: protective effects of R-alpha-lipoic acid.

Chronic systemic exposure of mice, rats, and Drosophila to D-galactose causes the acceleration of senescence and has been used as an aging model. The underlying mechanism is yet unclear. To investigate the mechanisms of neurodegeneration in this model, we studied cognitive function, hippocampal neuronal apoptosis and neurogenesis, and peripheral oxidative stress biomarkers, and also the protective effects of the antioxidant R-alpha-lipoic acid. Chronic systemic exposure of D-galactose (100 mg/kg, s.c., 7 weeks) to mice induced a spatial memory deficit, an increase in cell karyopyknosis, apoptosis and caspase-3 protein levels in hippocampal neurons, a decrease in the number of new neurons in the subgranular zone in the dentate gyrus, a reduction of migration of neural progenitor cells, and an increase in death of newly formed neurons in granular cell layer. The D-galactose exposure also induced an increase in peripheral oxidative stress, including an increase in malondialdehyde, a decrease in total anti-oxidative capabilities (T-AOC), total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) activities. A concomitant treatment with lipoic acid ameliorated cognitive dysfunction and neurodegeneration in the hippocampus, and also reduced peripheral oxidative damage by decreasing malondialdehyde and increasing T-AOC and T-SOD, without an effect on GSH-Px. These findings suggest that chronic D-galactose exposure induces neurodegeneration by enhancing caspase-mediated apoptosis and inhibiting neurogenesis and neuron migration, as well as increasing oxidative damage. In addition, D-galactose-induced toxicity in mice is a useful model for studying the mechanisms of neurodegeneration and neuroprotective drugs and agents.

Aging↗
PubMed2006

Genetic mechanisms for the synthesis of fucosyl GM1 in small cell lung cancer cell lines.

Fucosyl GM1 has been reported to be specifically expressed in small cell lung cancer (SCLC) cells. However, the genetic basis for the synthesis of fucosyl GM1 has not been investigated. We analyzed the glycosyltransferases responsible for the synthesis of fucosyl GM1 in SCLC cell lines. In four SCLC cell lines expressing fucosyl GM1, both FUT1 and FUT2 mRNAs were detected, indicating that either one or both of alpha1,2-fucosyltransferases may be involved in the expression of fucosyl GM1. However, three of these four lines contained function-loss mutations in the FUT2 coding region, suggesting that FUT1 is mainly involved in the alpha1,2-fucosylation of GM1. The expression levels of the GM1 synthase gene showed no correlation with those of fucosyl GM1, whereas the co-transfection of GM1 synthase cDNA with FUT1 or FUT2 into SK-LC-17 clearly enhanced the neo-expression of fucosyl GM1, indicating its essential role. In contrast, the co-transfection of GD3 synthase cDNA reduced the expression levels of fucosyl GM1 with FUT1 or FUT2. Consequently, FUT1 seems to mainly contribute to the expression of fucosyl GM1, although both FUT1 and FUT2 are capable of generating the antigen. These results should promote the functional analysis of fucosyl GM1 leading to the development of novel therapies for SCLC.

Blood Group Antigens↗
PubMed2006

CD147, MMP-2, MMP-9 and MVD-CD34 are significant predictors of recurrence after liver transplantation in hepatocellular carcinoma patients.

OBJECTIVE: The prognostic role of tumor biological markers (biomarkers) in predicting recurrence of hepatocellular carcinoma (HCC) was investigated in this study, the results of which may help to select appropriate candidates for liver transplantation (LT). METHODS: Tissue samples from 82 HCC patients with cirrhosis who had undergone LT were immunohistochemically stained with antibodies of anti-CD147, anti-matrix metalloproteinases-2 (MMP-2), MMP-9 and anti-vascular endothelial growth factor (VEGF). Tumor microvessel density (MVD) was evaluated by using CD34. Multivariate Cox regression analysis was performed to identify the relevant prognostic factors. RESULTS: A significant correlation was found between the expression of CD147, VEGF, MMP-2, MMP-9 and MVD-CD34 in HCC. Tumor CD147 expression (P < 0.0001), tumor MVD-CD34 (P < 0.0001), MMP-9 in stromal compartment (P = 0.0257) and tumor VEGF expression (P = 0.0335) were significantly associated with the recurrence in HCC patients after LT. Univariate analysis showed that strong CD147 expression and high MVD-CD34 were significantly associated with poor tumor recurrence-free survival after LT (P < 0.0001). Multivariate analysis indicated that CD147 (P = 0.0001), MVD-CD34 (P = 0.0118), MMP-2 (P = 0.0312) and MMP-9 (P = 0.0280) in stromal compartment were all significant predictors in predicting HCC recurrence, while VEGF, MMP-2 and MMP-9 in tumor compartment were not significantly associated with poor prognosis. CONCLUSIONS: The tumor biomarkers CD147 and MVD-CD34 are more feasible markers for rational selection of LT candidates with HCC. MMP-9 and MMP-2 expression in stromal compartment, combined with pTNM tumor grade, may be helpful in predicting poor prognosis in HCC patients after LT.

Adult↗
PubMed2006

Guided selection of an anti-gamma-seminoprotein human Fab for antibody directed enzyme prodrug therapy of prostate cancer.

BACKGROUND: The HAMA response is a major challenge when murine antibodies are repeatedly administered for antibody directed enzyme prodrug therapy in vivo. In this study we have achieved humanization of the anti-gamma-seminoprotein E(4)B(7) murine mAb by guided selection. METHODS: Using optimal Ig Fab primers, human Fd and CL gene repertoires were amplified by RT-PCR from PBMCs of prostate cancer patients. The human Lc gene repertoire was first paired with the murine Fd gene of E(4)B(7) mAb to construct a pComb3X hybrid Fab display library. This hybrid library was screened with purified gamma-seminoprotein antigen. The human Fd gene repertoire was then paired with the selected human Lc to construct a fully human Fab library. After four more rounds of panning, completely human Fab antibodies specific for gamma-seminoprotein were selected and further identified. RESULTS: First, using the E(4)B(7) Fd gene as a template, light chain shuffling was achieved by panning the hybrid library. Then, using the selected Lc as a template, a human Fab antibody against gamma-seminoprotein was produced through heavy chain Fd shuffling. Western blotting, ELISA, and flow cytometry results demonstrated that the resulting human Fab antibody resembled the parental E(4)B(7) mAb in that they both recognized the same epitope with similar affinities. Fluorescent cell staining and immunohistochemistry analysis further confirmed that this newly constructed human anti-gamma-seminoprotein Fab antibody indeed specifically bound prostate cancer cells and tissue. CONCLUSIONS: Through guided-selection, we successfully produced a human anti-gamma-seminoprotein Fab antibody. This work lays the foundation for optimal antibody-directed enzyme prodrug therapy of prostate cancer using a fully human Fab antibody.

Amino Acid Sequence↗
PubMed2006

Depression of biofilm formation and antibiotic resistance by sarA disruption in Staphylococcus epidermidis.

AIM: To study the effects of disruption of sarA gene on biofilm formation and antibiotic resistance of Staphylococcus epidermidis (S. epidermidis). METHODS: In order to disrupt sarA gene, the double-crossover homologous recombination was applied in S. epidermidis RP62A, and tetracycline resistance gene (tet) was used as the selective marker which was amplified by PCR from the pBR322 and inserted into the locus between sarA upstream and downstream, resulting in pBT2delta sarA. By electroporation, the plasmid pBT2delta sarA was transformed into S. epidermidis. Gene transcription was detected by real-time reverse transcription-PCR (RT-PCR). Determination of biofilm was performed in 96-well flat-bottomed culture plates, and antibiotic resistance was analyzed with test tube culture by spectrophotometry at 570 nm respectively. RESULTS: A sarA disrupted strain named S. epidermidis RP62Adelta sarA was constructed, which was completely defective in biofilm formation, while the sarA complement strain RP62Adelta sarA (pHPS9sarA) restored the biofilm formation phenotype. Additionally, the knockout of sarA resulted in decreased erythromycin and kanamycin resistance of S. epidermidis RP62A. Compared to the original strain, S. epidermidis RP62Adelta sarA had an increase of the sensitivity to erythromycin at 200-400 microg/mL and kanamycin at 200-800 microg/mL respectively. CONCLUSION: The knockout of sarA can result in the defect in biofilm formation and the decreased erythromycin and kanamycin resistance in S. epidermidis RP62A.

Bacterial Proteins↗
PubMed2006

Targeting radioimmunotherapy of hepatocellular carcinoma with iodine (131I) metuximab injection: clinical phase I/II trials.

PURPOSE: HAb18G/CD147 is a hepatocellular carcinoma (HCC)-associated antigen. We developed iodine (131I) metuximab injection (Licartin), a novel 131I-labeled HAb18G/CD147-specific monoclonal antibody Fab'2 fragment, and evaluated its safety, pharmacokinetics, and clinical efficacy on HCC in Phase I/II trials. METHODS AND MATERIALS: In a Phase I trial, 28 patients were randomly assigned to receive the injection in 9.25-, 18.5-, 27.75-, or 37-MBq/kg doses by hepatic artery infusion. In a multicenter Phase II trial, 106 patients received the injection (27.75 MBq/kg) on Day 1 of a 28-day cycle. Response rate and survival rate were the endpoints. RESULTS: No life-threatening toxic effects were found. The safe dosage was 27.75 MBq/kg. The blood clearance fitted a biphasic model, and its half-life was 90.56-63.93 h. In the Phase II trial, the injection was found to be targeted and concentrated to tumor tissues. Of the 73 patients completing two cycles, 6 (8.22%) had a partial response, 14 (19.18%) minor response, and 43 (58.90%) stable disease. The 21-month survival rate was 44.54%. The survival rate of progression-free patients was significantly higher than that of patients with progressive disease after either one or two cycles (p < 0.0001 or p = 0.0019). CONCLUSION: Iodine (131I) metuximab injection is safe and active for HCC patients.

Adolescent↗
PubMed2006

Catalytic detoxification of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in fly ash.

An efficient catalytic detoxification method for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in fly ash produced by municipal waste incinerator has been studied using palladium on carbon (Pd/C) catalyst. As one of the trace components in fly ash, the detoxification of PCDD/Fs is very difficult because of the interferences of other persistent components with higher concentrations. However, the detoxification reaction of PCDD/Fs shows higher activity in water/isopropanol solution using commercial Pd/C catalyst at 40 degrees C under normal pressure. The results indicated that the catalytic degradation of PCDFs has been found to be easier than that of PCDDs. Moreover, the dechlorination ratios were higher for octa- and hepta-chlorinated congeners than those for tetra- and penta-chlorinated ones. The detoxification process worked well in water. The dechlorination efficiencies of almost all of the PCDD/Fs congeners can reach over 99% within a shorter reaction time.

2-Propanol↗
PubMed2006

Optimal design of Ig 5' primers for construction of diverse phage antibody library established to select anti-HAb18GEF and anti-DOTA-Y Fabs for hepatoma pretargeting RIT.

Phage antibody library yields antibodies with higher affinity against different antigens, if diverse IgV gene repertoires can be amplified. As the currently available Fab primer sets cannot guarantee efficient amplification with high diversity, and because rare cloning sites can be found in certain Ig genes, here, we present an optimal set of Ig 5' primers, compatible with Fd 5' clone site replaced pComb3 vector, for diverse Fab phage display library construction. These novel Fab primes designed based on the newly classified IgV families, not only have best match and highest coverage for IgV family with minimized N-terminal amino acid changes, but also present good amplification diversity and efficiency of Ig gene from mice immunized with different forms of antigens (HAb18GEF, KLH-DOTA-Y, and HAb18G/pcDNA3). A high quality immune phage library with good diversity was constructed based on the mixed Ig repertoire, and five high affinity Fab antibodies were selected to specifically bind to HAb18GEF, DOTA-Y and an irrelevant antigen gamma-sm, respectively. This novel Fab primers set can be applied to the construction of diverse phage antibody library and the anti-HAb18GEF and anti-DOTA-Y Fab antibodies lay a solid foundation for radioimmunotherapy of hepatoma.

Animals↗
PubMed2006

Deglutitive upper esophageal sphincter relaxation: a study of 75 volunteer subjects using solid-state high-resolution manometry.

This study aimed to use a novel high-resolution manometry (HRM) system to establish normative values for deglutitive upper esophageal sphincter (UES) relaxation. Seventy-five asymptomatic controls were studied. A solid-state HRM assembly with 36 circumferential sensors spaced 1 cm apart was positioned to record from the hypopharynx to the stomach. Subjects performed ten 5-ml water swallows and one each of 1-, 10-, and 20-ml volume swallows. Pressure profiles across the UES were analyzed using customized computational algorithms that measured 1) the relaxation interval (RI), 2) the median intrabolus pressure (mIBP) during the RI, and 3) the deglutitive sphincter resistance (DSR) defined as mIBP/RI. The automated analysis succeeded in confirming bolus volume modulation of both the RI and the mIBP with the mean RI ranging from 0.32 to 0.50 s and mIBP ranging from 5.93 to 13.80 mmHg for 1- and 20-ml swallows, respectively. DSR was relatively independent of bolus volume. Peak pharyngeal contraction during the return to the resting state postswallow was almost 300 mmHg, again independent of bolus volume. We performed a detailed analysis of deglutitive UES relaxation with a novel HRM system and customized software. The enhanced spatial resolution of HRM allows for the accurate, automated assessment of UES relaxation and intrabolus pressure characteristics, in both cases confirming the volume-dependent effects and absolute values of these parameters previously demonstrated by detailed analysis of concurrent manometry/fluoroscopy data. Normative values were established to aid in future clinical and investigative studies.

Adult↗
PubMed2006

Phosphorylation of TNF-alpha converting enzyme by gastrin-releasing peptide induces amphiregulin release and EGF receptor activation.

G protein-coupled receptors induce EGF receptor (EGFR) signaling, leading to the proliferation and invasion of cancer cells. Elucidation of the mechanism of EGFR activation by G protein-coupled receptors may identify new signaling paradigms. A gastrin-releasing peptide (GRP)/GRP receptor-mediated autocrine pathway was previously described in squamous cell carcinoma of head and neck. In the present study, we demonstrate that TNF-alpha converting enzyme (TACE), a disintegrin and metalloproteinse-17, undergoes a Src-dependent phosphorylation that regulates release of the EGFR ligand amphiregulin upon GRP treatment. Further investigation reveals the phosphatidylinositol 3-kinase (PI3-K) as the intermediate of c-Src and TACE, contributing to their association and TACE phosphorylation. Phosphoinositide-dependent kinase 1 (PDK1), a downstream target of PI3-K, has been identified as the previously undescribed kinase to directly phosphorylate TACE upon GRP treatment. These findings suggest a signaling cascade of GRP-Src-PI3-K-PDK1-TACE-amphiregulin-EGFR with multiple points of interaction, translocation, and phosphorylation. Furthermore, knockdown of PDK1 augmented the antitumor effects of the EGFR inhibitor erlotinib, indicating PDK1 as a therapeutic target to improve the clinical response to EGFR inhibitors.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2006

Metastatic potential of mouse Lewis lung cancer cells is regulated via ganglioside GM1 by modulating the matrix metalloprotease-9 localization in lipid rafts.

To analyze mechanisms for cancer metastasis, we established high metastatic sublines from mouse Lewis lung cancer (P29) by repeated injection. Sublines established from the two subclones H7 and C4 commonly exhibited increased proliferation and invasion activity and reduced expression of ganglioside GM1, although they showed different preferences in their target organs of metastasis. The high metastatic sublines secreted higher levels of activated matrix metalloprotease (MMP)-9 as well as pro-MMP-9 in the culture medium than the parent lines. Furthermore, they contained MMP-9 at the glycolipid-enriched microdomain (GEM)/rafts fractionated by the sucrose density gradient ultracentrifugation of Triton X-100 extracts, whereas the parent cells showed faint bands at the fraction. When high metastatic sublines were treated with methyl-beta-cyclodextrin, their invasion activities were dramatically suppressed, and the MMP-9 secretion was also suppressed. All these results indicated that GEM/rafts play crucial roles in the increased invasion and high metastatic potential. To clarify the implication of reduced GM1 expression, low GM1-expressing cell lines were established using an RNA interference-expression vector of the GM1 synthase. Low GM1-expressing cell lines showed increased proliferation and invasion, enrichment in the GEM/rafts, and increased secretion of MMP-9. Among adhesion molecules, only integrin beta1 was detected in GEM/rafts with stronger intensity in high metastatic lines and low GM1-expressing cells. Taken together, integrins seemed to be enriched in the GEM/rafts by reduced GM1 levels, and subsequently MMP-9 was recruited to the GEM/rafts, resulting in its efficient secretion and activation, and eventually in the increased invasion and metastatic potentials.

Animals↗
PubMed2006

Differential change in left ventricular mass and regional wall thickness after cardiac resynchronization therapy for heart failure.

AIMS: LV reverse remodelling has been shown to be a favourable response after cardiac resynchronization therapy (CRT) in many clinical trials. This study investigated whether left ventricular (LV) reverse remodelling after CRT has any structural benefit, which include the improvement of LV mass or regional wall thickness. METHODS AND RESULTS: Fifty patients (66 +/- 11 years) receiving CRT were followed up for at least 3 months. Echocardiography with tissue Doppler imaging was performed serially before and at day 1 and 3 months after CRT. Although LV end-systolic volume (LVESV) was decreased at day 1 after CRT (141 +/- 74 vs. 129 +/- 71 cm(3), P < 0.001), further LV reverse remodelling was observed at 3 months (110 +/- 67 cm(3), P < 0.001 vs. day 1). LV ejection fraction increased at day 1 (26.5 +/- 9.3 vs. 28.5 +/- 9.1%, P < 0.005) and was further improved at 3 months (34.2 +/- 10.5%, P < 0.001 vs. day 1). However, reduction of LV mass (231 +/- 67 vs. 213 +/- 59 g, P < 0.001) and regional wall thickness was only observed at 3 months, but not at day 1. The improvement of LV mass correlated with the change in LVESV (r = 0.66, P < 0.001) and the baseline systolic asynchrony index (Ts-SD) (r = -0.52, P < 0.001). LV mass was only decreased significantly in responders of LV reverse remodelling (245 +/- 66 vs. 207 +/- 61 g, P < 0.001), but increased in non-responders (209 +/- 64 vs. 223 +/- 56 g, P = 0.02). Responders had significant decrease in thickness of all the four walls for -6 to -11% (all P < or =0.02), whereas non-responders had increased thickness in septal and lateral walls for +11% (both P < 0.05). CONCLUSION: The acute reduction in LV volume after CRT is mediated by haemodynamic and geometric benefits without actual changes in LV mass. However, at 3-month follow-up, reduction in LV mass and regional wall thickness was demonstrated, which represents structural reverse remodelling. Such benefit was only observed in volumetric responders but was worsened in non-responders.

Aged↗
PubMed2006

Flexible histone tails in a new mesoscopic oligonucleosome model.

We describe a new mesoscopic model of oligonucleosomes that incorporates flexible histone tails. The nucleosome cores are modeled using the discrete surface-charge optimization model, which treats the nucleosome as an electrostatic surface represented by hundreds of point charges; the linker DNAs are treated using a discrete elastic chain model; and the histone tails are modeled using a bead/chain hydrodynamic approach as chains of connected beads where each bead represents five protein residues. Appropriate charges and force fields are assigned to each histone chain so as to reproduce the electrostatic potential, structure, and dynamics of the corresponding atomistic histone tails at different salt conditions. The dynamics of resulting oligonucleosomes at different sizes and varying salt concentrations are simulated by Brownian dynamics with complete hydrodynamic interactions. The analyses demonstrate that the new mesoscopic model reproduces experimental results better than its predecessors, which modeled histone tails as rigid entities. In particular, our model with flexible histone tails: correctly accounts for salt-dependent conformational changes in the histone tails; yields the experimentally obtained values of histone-tail mediated core/core attraction energies; and considers the partial shielding of electrostatic repulsion between DNA linkers as a result of the spatial distribution of histone tails. These effects are crucial for regulating chromatin structure but are absent or improperly treated in models with rigid histone tails. The development of this model of oligonucleosomes thus opens new avenues for studying the role of histone tails and their variants in mediating gene expression through modulation of chromatin structure.

Binding Sites↗
PubMed2006

A nonprostanoid EP4 receptor selective prostaglandin E2 agonist restores bone mass and strength in aged, ovariectomized rats.

UNLABELLED: CP432 is a newly discovered, nonprostanoid EP4 receptor selective prostaglandin E2 agonist. CP432 stimulates trabecular and cortical bone formation and restores bone mass and bone strength in aged ovariectomized rats with established osteopenia. INTRODUCTION: The purpose of this study was to determine whether a newly discovered, nonprostanoid EP4 receptor selective prostaglandin E2 (PGE2) agonist, CP432, could produce bone anabolic effects in aged, ovariectomized (OVX) rats with established osteopenia. MATERIALS AND METHODS: CP432 at 0.3, 1, or 3 mg/kg/day was given for 6 weeks by subcutaneous injection to 12-month-old rats that had been OVX for 8.5 months. The effects on bone mass, bone formation, bone resorption, and bone strength were determined. RESULTS: Total femoral BMD increased significantly in OVX rats treated with CP432 at all doses. CP432 completely restored trabecular bone volume of the third lumbar vertebral body accompanied with a dose-dependent decrease in osteoclast number and osteoclast surface and a dose-dependent increase in mineralizing surface, mineral apposition rate, and bone formation rate-tissue reference in OVX rats. CP432 at 1 and 3 mg/kg/day significantly increased total tissue area, cortical bone area, and periosteal and endocortical bone formation in the tibial shafts compared with both sham and OVX controls. CP432 at all doses significantly and dose-dependently increased ultimate strength in the fifth lumber vertebral body compared with both sham and OVX controls. At 1 and 3 mg/kg/day, CP432 significantly increased maximal load in a three-point bending test of femoral shaft compared with both sham and OVX controls. CONCLUSIONS: CP432 completely restored trabecular and cortical bone mass and strength in established osteopenic, aged OVX rats by stimulating bone formation and inhibiting bone resorption on trabecular and cortical surfaces.

Aging↗
PubMed2006

Never smokers and lung cancer risk: a case-control study of epidemiological factors.

We performed an analysis of potential epidemiological risk factors for lung cancer using data from 280 cases and 242 hospital-based controls, all lifetime never smokers (those who had smoked <100 cigarettes in their lifetimes) and frequency matched on age, gender and ethnicity. The data on demographic characteristics, medical history of respiratory diseases (asthma, emphysema, pneumonia and hay fever), weight and height, family history, female characteristics and environmental tobacco smoke (ETS) and dust exposure were derived from personal interviews. We performed a logistic regression analysis of these variables adjusting for age, gender, ethnicity, income and years of education. Exposure to ETS (OR = 2.08, 95% CI [1.25-3.43]) and dusts (OR = 2.43, 95% CI [1.53-3.88]) were associated with significantly increased risk. In the analysis for joint effects, exposure to both ETS and dusts conferred a higher risk (OR = 3.25, 95% CI [1.58-6.70]) than exposure to either alone. Family history of any cancer with onset before age 50 in at least 1 first degree relative was a significant risk predictor (OR = 1.70, 95% CI [1.10-2.64]). Individuals with a self-reported physician-diagnosed history of hay fever, but not asthma, had a decreased lung cancer risk (OR = 0.57, 95% CI [0.35-0.92]). In the multivariate analysis, exposure to ETS and dusts, and family history of cancer with onset before age 50 were significant risk factors, while a history of hay fever (occurring without asthma) was significantly protective.

Adult↗
PubMed2006

Molecular relaxation dynamics of self-assembled monolayers.

Dielectric relaxation spectroscopy is used to quantify molecular motion in alkylsilane SAMs coated on porous glass over a broad temperature range, -30 to -150 degrees C. Systematic measurements using SAMs with variable coating densities allow us to determine the effect of monolayer disorder on molecular mobility in thin molecular films. A relaxation process with an activation energy of approximately 25 kJ/mol is found to dominate dynamics of SAM-chain segments near the substrate. By introducing polar CN groups at the ends of the chain, we show that the relaxation process in the monolayer canopy can be isolated and studied. This approach can be generalized to other substituent polar groups to probe localized relaxation dynamics in surface-grafted monolayer films.

Journal Article↗