Tara Sabo-attwood - Academia.edu (original) (raw)

Papers by Tara Sabo-attwood

Research paper thumbnail of A Comparison of Methods for Sex Steroid Hormone Adjustment, National Health and Nutrition Examination Survey (NHANES III)

Research paper thumbnail of A Two-Component <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>G</mi></mrow><annotation encoding="application/x-tex">G</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6833em;"></span><span class="mord mathnormal">G</span></span></span></span> -Prior for Variable Selection

Research paper thumbnail of Influence of sex and disease severity on gene expression profiles in individuals with idiopathic pulmonary fibrosis

International journal of molecular epidemiology and genetics, 2014

Epidemiological studies suggest sex-specific trends in the prevalence and mortality of idiopathic... more Epidemiological studies suggest sex-specific trends in the prevalence and mortality of idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) that are distinct for each disease. While the expression of numerous immune and extracellular matrix (ECM) genes in the lung have been well characterized in these diseases, associations elucidating their sex-specific expression patterns by disease type and severity, and the evaluation of hormone-related genes, have not been well studied. Here we performed targeted transcriptional profiling of 48 genes was performed on lung tissue samples from males and females with mild or medium severity IPF or COPD. The genes assessed included those involved in inflammation, ECM remodeling and hormonal processes. Data for 36 lung tissue samples were obtained that were stratified by disease and sex. Expression levels revealed a subset of genes which show differential expression among sexes, disease type, and disease severity. The...

Research paper thumbnail of A cross-sectional study of the association of age, race and ethnicity, and body mass index with sex steroid hormone marker profiles among men in the National Health and Nutrition Examination Survey (NHANES III)

Research paper thumbnail of A Review of the Expression of Genes Involved in Sex Steroid Hormone Metabolism in Prostate Tissue: A Need for Epigenetic Information

Research paper thumbnail of “Linearity assessment methods for sex steroid hormones and carrier proteins among men in the National Health and Nutrition Examination Survey (NHANES III)”

Steroids, 2014

It has been hypothesized that racial disparities among several diseases are explained by differen... more It has been hypothesized that racial disparities among several diseases are explained by differences in testosterone (T), 17-β estradiol (E), sex hormone binding globulin (SHBG) and albumin (A) levels, yet epidemiologic results have been mixed. Statistical advice regarding appropriate adjustment methods for carrier proteins of sex steroid hormones in the literature is scant. Therefore, we investigated different adjustment methods for carrier proteins. Data for 1496 men, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;17 years from the Third National Health and Nutrition Examination Survey (NHANES III) 1988-91 were used to analyze linearity between sex hormones and carrier proteins by examining correlation, plots, and regression models. The statistical importance of age, body mass index (BMI), and race/ethnicity were examined for changes in results by the adjustment method. T was weakly correlated with SHBG and A (r-squared, 0.25, 0.13, respectively) and E was weakly negatively correlated with A (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001), but not SHBG (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.1799). Based on the model residual plots and r-squared, the categorical model performed better than linear models. Regression coefficients for age, BMI, and race/ethnicity groups using quotient (e.g., T/A and E/A) models differed from continuous and categorical models. Choosing an appropriate adjustment for carrier proteins is important to prevent bias in analyses and inconsistency in findings across studies. Linearity between variables should not be assumed when adjusting models, and should be conducted and reported. An independent categorical carrier protein variable is recommended in analysis exploring factors predicting sex hormone levels, although statistical testing should always be employed.

Research paper thumbnail of Estrogenic modulation of inflammation-related genes in male rats following volume overload

Physiological Genomics, 2012

Our laboratory has previously reported significant increases of the proinflammatory cytokine TNF-... more Our laboratory has previously reported significant increases of the proinflammatory cytokine TNF-␣ in male hearts secondary to sustained volume overload. These elevated levels of TNF-␣ are accompanied by left ventricular (LV) dilatation and cardiac dysfunction. In contrast, estrogen has been shown to protect against this adverse cardiac remodeling in both female and male rats. The purpose of this study was to determine whether estrogen has an effect on inflammation-related genes that contribute to this estrogen-mediated cardioprotection. Myocardial volume overload was induced by aortocaval fistula in 8 wk old male Sprague-Dawley rats (n ϭ 30), and genes of interest were identified using an inflammatory PCR array in Sham, Fistula, and Fistula ϩ Estrogen-treated (0.02 mg/kg per day beginning 2 wk prior to fistula) groups. A total of 55 inflammatory genes were modified (Ն2-fold change) at 3 days postfistula. The number of inflammatory gene was reduced to 21 genes by estrogen treatment, whereas 13 genes were comparably modulated in both fistula groups. The most notable were TNF-␣, which was downregulated by estrogen, and the TNF-␣ receptors, which were differentially regulated by estrogen. Specific genes related to arachidonic acid metabolism were downregulated by estrogen, including cyclooxygenase-1 and -2. Finally, gene expression for the ␤1-integrin cell adhesion subunit was significantly upregulated in the LV of estrogen-treated animals. Protein levels reflected the changes observed at the gene level. These data suggest that estrogen provides its cardioprotective effects, at least in part, via genomic modulation of numerous inflammation-related genes. aortocaval fistula; tumor necrosis factor-␣; tumor necrosis factor-␣ receptors; prostaglandin; ␤1-integrin THE ABDOMINAL AORTOCAVAL FISTULA model of volume overload is an excellent approach in which to study sex differences in heart failure. In this model, males undergo collagen degradation and develop significant left ventricular (LV) wall thinning, ventricular dilatation, and increased myocardial compliance , which ultimately progress to congestive heart failure (9). Meanwhile, females develop concentric myocardial remodeling, wherein the LV mass-to-volume ratio increases to maintain normal cardiac function (17). We have shown that this cardioprotection in female rats is modulated by ovarian hormones, chiefly estrogen (8, 18), since following ovariectomy, chronic volume overload induces adverse cardiac remodeling nearly identical to that of males (8). Conversely, estrogen supplementation in ovariectomized female

Research paper thumbnail of Birth order modifies the effect of IL13 gene polymorphisms on serum IgE at age 10 and skin prick test at ages 4, 10 and 18: a prospective birth cohort study

Allergy, Asthma & Clinical Immunology, 2010

Background: Susceptibility to atopy originates from effects of the environment on genes. Birth or... more Background: Susceptibility to atopy originates from effects of the environment on genes. Birth order has been identified as a risk factor for atopy and evidence for some candidate genes has been accumulated; however no study has yet assessed a birth order-gene interaction. Objective: To investigate the interaction of IL13 polymorphisms with birth order on allergic sensitization at ages 4, 10 and 18 years.

Research paper thumbnail of Course Syllabus ENHS 664: Environmental Genomics Spring 2009

COURSE DESCRIPTION: This course will provide students with an in-depth understanding of "state of... more COURSE DESCRIPTION: This course will provide students with an in-depth understanding of "state of the art" molecular techniques that are currently used to elucidate mechanisms of environmental contaminants in model systems. The course will focus on genetic/genomic approaches to studying molecular events perturbed by environmental agents in microbial, invertebrate, aquatic, plant, and mammalian model systems. The course consists of lectures, hands-on laboratory procedures, and informal discussions. An emphasis will be placed on experimental design, execution and data analysis. The learning process will be aided with challenging assignments that will introduce you to many of the current tools used in assessment of toxic compounds and other factors of anthropogenic change and risks related to human and ecological health.

Research paper thumbnail of Tomographic Investigations Relevant to the Rhizosphere

SSSA Special Publication, 2013

Research paper thumbnail of Uptake, distribution and toxicity of gold nanoparticles in tobacco ( Nicotiana xanthi ) seedlings

Nanotoxicology, 2012

Understanding plant interactions with nanoparticles is of increasing importance for assessing the... more Understanding plant interactions with nanoparticles is of increasing importance for assessing their toxicity and trophic transport. The primary objective of this study was to assess uptake, biodistribution and toxicity associated with exposure of tobacco plants (Nicotiana xanthi) to gold nanoparticles (AuNPs). We employed synchrotron-based X-ray microanalysis with X-ray absorption near-edge microspectroscopy and high resolution electron microscopy to localize AuNPs within plants. Results from these experiments reveal that AuNPs entered plants through the roots and moved into the vasculature. Aggregate bodies were also detected within root cell cytoplasm. Furthermore, AuNP uptake was size selective as 3.5 nm AuNP spheres were detected in plants but 18 nm AuNPs remained agglomerated on the root outer surfaces. Finally, leaf necrosis was observed after 14 days of exposure to 3.5 nm AuNPs. Overall, results of this work show the potential for AuNPs to enter plants through size-dependent mechanisms, translocate to cells and tissues and cause biotoxicity.

Research paper thumbnail of Targeted Photothermal Lysis of the Pathogenic Bacteria, Pseudomonas aeruginosa , with Gold Nanorods

Nano Letters, 2008

Increases in the prevalence of antibiotic resistant bacteria require new approaches for the treat... more Increases in the prevalence of antibiotic resistant bacteria require new approaches for the treatment of infectious bacterial pathogens. It is now clear that a nanotechnology-driven approach using nanoparticles to selectively target and destroy pathogenic bacteria can be successfully implemented. We have explored this approach by using gold nanorods that have been covalently linked to primary antibodies to selectively destroy the pathogenic Gram-negative bacterium, Pseudomonas aeruginosa. We find that, following nanorod attachment to the bacterial cell surface, exposure to near-infrared radiation results in a significant reduction in bacterial cell viability.

Research paper thumbnail of Regulation of osteogenic differentiation of rat bone marrow stromal cells on 2D nanorod substrates

Biomaterials, 2010

Bone marrow stromal cells (BMSCs) possess multi-lineage differentiation potential and can be indu... more Bone marrow stromal cells (BMSCs) possess multi-lineage differentiation potential and can be induced to undergo differentiation into various cell types with the correct combination of chemical and environmental factors. Although, they have shown great prospects in therapeutic and medical applications, less is known about their behavior on nanosurfaces mimicking the extra cellular matrix (ECM). In this report we have employed 2D substrates coated with tobacco mosaic virus (TMV) nanorods to study the differentiation process of BMSCs into osteoblast like cells. TMV is a rod-shaped plant virus with an average length of 300 nm and diameter of 18 nm. The osteogenic differentiation of BMSCs on TMV was studied over time points of 7, 14 and 21 days. We examined the temporal gene expression changes during these time points by real-time quantitative PCR (RT-qPCR) analysis. As expected, osteo-specific genes (osteocalcin, osteopontin and osteonectin) were upregulated and showed a maximum change in expression on TMV at 14 days which was 7 days earlier than on tissue culture plastic (TCP). Based on the genes expression profile generated by RT-qPCR experiments, we proposed that the early interaction of cells with TMV triggers on signaling pathways which regulate speedy expression of osteocalcin in turn, resulting in early mineralization of the cells. To further investigate these regulating factors we studied global changes in gene expression (DNA microarray analyses) during osteogenic differentiation on the nanosubstrate. Multitudes of genes were affected by culturing cells on nanorod substrate, which corroborated our initial PCR findings. Microarray analysis further revealed additional targets influenced by the presence of nanorods on the surface, of which, the expression of bone morphogenetic protein 2 (BMP2) was of particular interests. Further investigation into the temporal change of BMP2, revealed that it acts as a major promoter in signaling the early regulation of osteocalcin on TMV coated substrates.

Research paper thumbnail of Ecotoxicity test methods for engineerd nanomaterials: practical experiences and recommendations from the bench

Environmental Toxicology and Chemistry, 2012

Ecotoxicology research is using many methods for engineered nanomaterials (ENMs), but the collect... more Ecotoxicology research is using many methods for engineered nanomaterials (ENMs), but the collective experience from researchers has not been documented. This paper reports the practical issues for working with ENMs and suggests nano-specific modifications to protocols. The review considers generic practical issues, as well as specific issues for aquatic tests, marine grazers, soil organisms, and bioaccumulation studies. Current procedures for

Research paper thumbnail of Dynamism of Stimuli-Responsive Nanohybrids: Environmental Implications

Research paper thumbnail of Examination of Single-Walled Carbon Nanotubes Uptake and Toxicity from Dietary Exposure: Tracking Movement and Impacts in the Gastrointestinal System

Research paper thumbnail of Change in chirality of semiconducting single-walled carbon nanotubes can overcome anionic surfactant stabilisation: a systematic study of aggregation kinetics

Environmental Chemistry, 2015

Single-walled carbon nanotubes&amp;amp;amp;amp;amp;amp;amp;amp;#39; (SWNT) effectiveness in a... more Single-walled carbon nanotubes&amp;amp;amp;amp;amp;amp;amp;amp;#39; (SWNT) effectiveness in applications is enhanced by debundling or stabilization. Anionic surfactants are known to effectively stabilize SWNTs. However, the role of specific chirality on surfactant-stabilized SWNT aggregation has not been studied to date. The aggregation behavior of chirally enriched (6,5) and (7,6) semiconducting SWNTs, functionalized with three anionic surfactants-sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium deoxycholate (SDOCO)-was evaluated with time-resolved dynamic light scattering. A wide range of mono- (NaCl) and di-valent (CaCl2) electrolytes as well as a 2.5 mg TOC/L Suwannee River humic acid (SRHA) were used as background chemistry. Overall, SDBS showed the most effectiveness in SWNT stability, followed by SDOCO and SDS. However, the relatively larger diameter (7,6) chiral tubes compromised the surfactant stability, compared to (6,5) chiral enrichment, due to enhanced van der Waals interaction. The presence of di-valent electrolytes overshadowed the chirality effects and resulted in similar aggregation behavior for both the SWNT samples. Molecular modeling results enumerated key differences in surfactant conformation on SWNT surfaces and identified interaction energy changes between the two chiralities to delineate aggregation mechanisms. The stability of SWNTs increased in the presence of SRHA under 10 mM monovalent and mixed electrolyte conditions. The results suggest that change in chirality can overcome surfactant stabilization of semiconducting SWNTs. SWNT stability can also be strongly influenced by the anionic surfactant structure.

Research paper thumbnail of Fate of single walled carbon nanotubes in wetland ecosystems

Environ. Sci.: Nano, 2014

Research paper thumbnail of Control of Transcriptional Repression of the Vitellogenin Receptor Gene in Largemouth Bass (Micropterus Salmoides) by Select Estrogen Receptors Isotypes

Toxicological Sciences, 2014

The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor func... more The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor functions to incorporate vitellogenin (Vtg), a macromolecule synthesized and released from the liver in the bloodstream, into oocytes where it is processed into yolk. Although studies have focused on the functional role of Vtgr in fish, the mechanistic control of this gene is still unexplored. Here we report the identification and analysis of the first piscine 5 regulatory region of the vtgr gene which was cloned from largemouth bass (Micropterus salmoides). Using this putative promoter sequence, we investigated a role for hormones, including insulin and 17␤-estradiol (E 2 ), in transcriptional regulation through cell-based reporter assays. No effect of insulin was observed, however, E 2 was able to repress transcriptional activity of the vtgr promoter through select estrogen receptor subtypes, Esr1 and Esr2a but not Esr2b. Electrophoretic mobility shift assay demonstrated that Esr1 likely interacts with the vtgr promoter region through half ERE and/or SP1 sites, in part. Finally we also show that ethinylestradiol (EE 2 ), but not bisphenol-A (BPA), represses promoter activity similarly to E 2 . These results reveal for the first time that the Esr1 isoform may play an inhibitory role in the expression of LMB vtgr mRNA under the influence of E 2 , and potent estrogens such as EE 2 . In addition, this new evidence suggests that vtgr may be a target of select endocrine disrupting compounds through environmental exposures.

Research paper thumbnail of Environmental Carcinogenesis

Oncology, 2006

Environmental carcinogens are broadly defined as compounds that humans are exposed to through die... more Environmental carcinogens are broadly defined as compounds that humans are exposed to through diet, lifestyle, infectious agents, and occupation. They are considered as nongenetic factors that contribute to cancer risk. A subset of known and reasonably anticipated human carcinogens can be classified as environmental carcinogens and include such compounds as dioxins, metals, components of pesticides, the polyaromatic hydrocarbon (PAH) benzo(a)pyrene

Research paper thumbnail of A Comparison of Methods for Sex Steroid Hormone Adjustment, National Health and Nutrition Examination Survey (NHANES III)

Research paper thumbnail of A Two-Component <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>G</mi></mrow><annotation encoding="application/x-tex">G</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6833em;"></span><span class="mord mathnormal">G</span></span></span></span> -Prior for Variable Selection

Research paper thumbnail of Influence of sex and disease severity on gene expression profiles in individuals with idiopathic pulmonary fibrosis

International journal of molecular epidemiology and genetics, 2014

Epidemiological studies suggest sex-specific trends in the prevalence and mortality of idiopathic... more Epidemiological studies suggest sex-specific trends in the prevalence and mortality of idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) that are distinct for each disease. While the expression of numerous immune and extracellular matrix (ECM) genes in the lung have been well characterized in these diseases, associations elucidating their sex-specific expression patterns by disease type and severity, and the evaluation of hormone-related genes, have not been well studied. Here we performed targeted transcriptional profiling of 48 genes was performed on lung tissue samples from males and females with mild or medium severity IPF or COPD. The genes assessed included those involved in inflammation, ECM remodeling and hormonal processes. Data for 36 lung tissue samples were obtained that were stratified by disease and sex. Expression levels revealed a subset of genes which show differential expression among sexes, disease type, and disease severity. The...

Research paper thumbnail of A cross-sectional study of the association of age, race and ethnicity, and body mass index with sex steroid hormone marker profiles among men in the National Health and Nutrition Examination Survey (NHANES III)

Research paper thumbnail of A Review of the Expression of Genes Involved in Sex Steroid Hormone Metabolism in Prostate Tissue: A Need for Epigenetic Information

Research paper thumbnail of “Linearity assessment methods for sex steroid hormones and carrier proteins among men in the National Health and Nutrition Examination Survey (NHANES III)”

Steroids, 2014

It has been hypothesized that racial disparities among several diseases are explained by differen... more It has been hypothesized that racial disparities among several diseases are explained by differences in testosterone (T), 17-β estradiol (E), sex hormone binding globulin (SHBG) and albumin (A) levels, yet epidemiologic results have been mixed. Statistical advice regarding appropriate adjustment methods for carrier proteins of sex steroid hormones in the literature is scant. Therefore, we investigated different adjustment methods for carrier proteins. Data for 1496 men, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;17 years from the Third National Health and Nutrition Examination Survey (NHANES III) 1988-91 were used to analyze linearity between sex hormones and carrier proteins by examining correlation, plots, and regression models. The statistical importance of age, body mass index (BMI), and race/ethnicity were examined for changes in results by the adjustment method. T was weakly correlated with SHBG and A (r-squared, 0.25, 0.13, respectively) and E was weakly negatively correlated with A (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001), but not SHBG (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.1799). Based on the model residual plots and r-squared, the categorical model performed better than linear models. Regression coefficients for age, BMI, and race/ethnicity groups using quotient (e.g., T/A and E/A) models differed from continuous and categorical models. Choosing an appropriate adjustment for carrier proteins is important to prevent bias in analyses and inconsistency in findings across studies. Linearity between variables should not be assumed when adjusting models, and should be conducted and reported. An independent categorical carrier protein variable is recommended in analysis exploring factors predicting sex hormone levels, although statistical testing should always be employed.

Research paper thumbnail of Estrogenic modulation of inflammation-related genes in male rats following volume overload

Physiological Genomics, 2012

Our laboratory has previously reported significant increases of the proinflammatory cytokine TNF-... more Our laboratory has previously reported significant increases of the proinflammatory cytokine TNF-␣ in male hearts secondary to sustained volume overload. These elevated levels of TNF-␣ are accompanied by left ventricular (LV) dilatation and cardiac dysfunction. In contrast, estrogen has been shown to protect against this adverse cardiac remodeling in both female and male rats. The purpose of this study was to determine whether estrogen has an effect on inflammation-related genes that contribute to this estrogen-mediated cardioprotection. Myocardial volume overload was induced by aortocaval fistula in 8 wk old male Sprague-Dawley rats (n ϭ 30), and genes of interest were identified using an inflammatory PCR array in Sham, Fistula, and Fistula ϩ Estrogen-treated (0.02 mg/kg per day beginning 2 wk prior to fistula) groups. A total of 55 inflammatory genes were modified (Ն2-fold change) at 3 days postfistula. The number of inflammatory gene was reduced to 21 genes by estrogen treatment, whereas 13 genes were comparably modulated in both fistula groups. The most notable were TNF-␣, which was downregulated by estrogen, and the TNF-␣ receptors, which were differentially regulated by estrogen. Specific genes related to arachidonic acid metabolism were downregulated by estrogen, including cyclooxygenase-1 and -2. Finally, gene expression for the ␤1-integrin cell adhesion subunit was significantly upregulated in the LV of estrogen-treated animals. Protein levels reflected the changes observed at the gene level. These data suggest that estrogen provides its cardioprotective effects, at least in part, via genomic modulation of numerous inflammation-related genes. aortocaval fistula; tumor necrosis factor-␣; tumor necrosis factor-␣ receptors; prostaglandin; ␤1-integrin THE ABDOMINAL AORTOCAVAL FISTULA model of volume overload is an excellent approach in which to study sex differences in heart failure. In this model, males undergo collagen degradation and develop significant left ventricular (LV) wall thinning, ventricular dilatation, and increased myocardial compliance , which ultimately progress to congestive heart failure (9). Meanwhile, females develop concentric myocardial remodeling, wherein the LV mass-to-volume ratio increases to maintain normal cardiac function (17). We have shown that this cardioprotection in female rats is modulated by ovarian hormones, chiefly estrogen (8, 18), since following ovariectomy, chronic volume overload induces adverse cardiac remodeling nearly identical to that of males (8). Conversely, estrogen supplementation in ovariectomized female

Research paper thumbnail of Birth order modifies the effect of IL13 gene polymorphisms on serum IgE at age 10 and skin prick test at ages 4, 10 and 18: a prospective birth cohort study

Allergy, Asthma & Clinical Immunology, 2010

Background: Susceptibility to atopy originates from effects of the environment on genes. Birth or... more Background: Susceptibility to atopy originates from effects of the environment on genes. Birth order has been identified as a risk factor for atopy and evidence for some candidate genes has been accumulated; however no study has yet assessed a birth order-gene interaction. Objective: To investigate the interaction of IL13 polymorphisms with birth order on allergic sensitization at ages 4, 10 and 18 years.

Research paper thumbnail of Course Syllabus ENHS 664: Environmental Genomics Spring 2009

COURSE DESCRIPTION: This course will provide students with an in-depth understanding of "state of... more COURSE DESCRIPTION: This course will provide students with an in-depth understanding of "state of the art" molecular techniques that are currently used to elucidate mechanisms of environmental contaminants in model systems. The course will focus on genetic/genomic approaches to studying molecular events perturbed by environmental agents in microbial, invertebrate, aquatic, plant, and mammalian model systems. The course consists of lectures, hands-on laboratory procedures, and informal discussions. An emphasis will be placed on experimental design, execution and data analysis. The learning process will be aided with challenging assignments that will introduce you to many of the current tools used in assessment of toxic compounds and other factors of anthropogenic change and risks related to human and ecological health.

Research paper thumbnail of Tomographic Investigations Relevant to the Rhizosphere

SSSA Special Publication, 2013

Research paper thumbnail of Uptake, distribution and toxicity of gold nanoparticles in tobacco ( Nicotiana xanthi ) seedlings

Nanotoxicology, 2012

Understanding plant interactions with nanoparticles is of increasing importance for assessing the... more Understanding plant interactions with nanoparticles is of increasing importance for assessing their toxicity and trophic transport. The primary objective of this study was to assess uptake, biodistribution and toxicity associated with exposure of tobacco plants (Nicotiana xanthi) to gold nanoparticles (AuNPs). We employed synchrotron-based X-ray microanalysis with X-ray absorption near-edge microspectroscopy and high resolution electron microscopy to localize AuNPs within plants. Results from these experiments reveal that AuNPs entered plants through the roots and moved into the vasculature. Aggregate bodies were also detected within root cell cytoplasm. Furthermore, AuNP uptake was size selective as 3.5 nm AuNP spheres were detected in plants but 18 nm AuNPs remained agglomerated on the root outer surfaces. Finally, leaf necrosis was observed after 14 days of exposure to 3.5 nm AuNPs. Overall, results of this work show the potential for AuNPs to enter plants through size-dependent mechanisms, translocate to cells and tissues and cause biotoxicity.

Research paper thumbnail of Targeted Photothermal Lysis of the Pathogenic Bacteria, Pseudomonas aeruginosa , with Gold Nanorods

Nano Letters, 2008

Increases in the prevalence of antibiotic resistant bacteria require new approaches for the treat... more Increases in the prevalence of antibiotic resistant bacteria require new approaches for the treatment of infectious bacterial pathogens. It is now clear that a nanotechnology-driven approach using nanoparticles to selectively target and destroy pathogenic bacteria can be successfully implemented. We have explored this approach by using gold nanorods that have been covalently linked to primary antibodies to selectively destroy the pathogenic Gram-negative bacterium, Pseudomonas aeruginosa. We find that, following nanorod attachment to the bacterial cell surface, exposure to near-infrared radiation results in a significant reduction in bacterial cell viability.

Research paper thumbnail of Regulation of osteogenic differentiation of rat bone marrow stromal cells on 2D nanorod substrates

Biomaterials, 2010

Bone marrow stromal cells (BMSCs) possess multi-lineage differentiation potential and can be indu... more Bone marrow stromal cells (BMSCs) possess multi-lineage differentiation potential and can be induced to undergo differentiation into various cell types with the correct combination of chemical and environmental factors. Although, they have shown great prospects in therapeutic and medical applications, less is known about their behavior on nanosurfaces mimicking the extra cellular matrix (ECM). In this report we have employed 2D substrates coated with tobacco mosaic virus (TMV) nanorods to study the differentiation process of BMSCs into osteoblast like cells. TMV is a rod-shaped plant virus with an average length of 300 nm and diameter of 18 nm. The osteogenic differentiation of BMSCs on TMV was studied over time points of 7, 14 and 21 days. We examined the temporal gene expression changes during these time points by real-time quantitative PCR (RT-qPCR) analysis. As expected, osteo-specific genes (osteocalcin, osteopontin and osteonectin) were upregulated and showed a maximum change in expression on TMV at 14 days which was 7 days earlier than on tissue culture plastic (TCP). Based on the genes expression profile generated by RT-qPCR experiments, we proposed that the early interaction of cells with TMV triggers on signaling pathways which regulate speedy expression of osteocalcin in turn, resulting in early mineralization of the cells. To further investigate these regulating factors we studied global changes in gene expression (DNA microarray analyses) during osteogenic differentiation on the nanosubstrate. Multitudes of genes were affected by culturing cells on nanorod substrate, which corroborated our initial PCR findings. Microarray analysis further revealed additional targets influenced by the presence of nanorods on the surface, of which, the expression of bone morphogenetic protein 2 (BMP2) was of particular interests. Further investigation into the temporal change of BMP2, revealed that it acts as a major promoter in signaling the early regulation of osteocalcin on TMV coated substrates.

Research paper thumbnail of Ecotoxicity test methods for engineerd nanomaterials: practical experiences and recommendations from the bench

Environmental Toxicology and Chemistry, 2012

Ecotoxicology research is using many methods for engineered nanomaterials (ENMs), but the collect... more Ecotoxicology research is using many methods for engineered nanomaterials (ENMs), but the collective experience from researchers has not been documented. This paper reports the practical issues for working with ENMs and suggests nano-specific modifications to protocols. The review considers generic practical issues, as well as specific issues for aquatic tests, marine grazers, soil organisms, and bioaccumulation studies. Current procedures for

Research paper thumbnail of Dynamism of Stimuli-Responsive Nanohybrids: Environmental Implications

Research paper thumbnail of Examination of Single-Walled Carbon Nanotubes Uptake and Toxicity from Dietary Exposure: Tracking Movement and Impacts in the Gastrointestinal System

Research paper thumbnail of Change in chirality of semiconducting single-walled carbon nanotubes can overcome anionic surfactant stabilisation: a systematic study of aggregation kinetics

Environmental Chemistry, 2015

Single-walled carbon nanotubes&amp;amp;amp;amp;amp;amp;amp;amp;#39; (SWNT) effectiveness in a... more Single-walled carbon nanotubes&amp;amp;amp;amp;amp;amp;amp;amp;#39; (SWNT) effectiveness in applications is enhanced by debundling or stabilization. Anionic surfactants are known to effectively stabilize SWNTs. However, the role of specific chirality on surfactant-stabilized SWNT aggregation has not been studied to date. The aggregation behavior of chirally enriched (6,5) and (7,6) semiconducting SWNTs, functionalized with three anionic surfactants-sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium deoxycholate (SDOCO)-was evaluated with time-resolved dynamic light scattering. A wide range of mono- (NaCl) and di-valent (CaCl2) electrolytes as well as a 2.5 mg TOC/L Suwannee River humic acid (SRHA) were used as background chemistry. Overall, SDBS showed the most effectiveness in SWNT stability, followed by SDOCO and SDS. However, the relatively larger diameter (7,6) chiral tubes compromised the surfactant stability, compared to (6,5) chiral enrichment, due to enhanced van der Waals interaction. The presence of di-valent electrolytes overshadowed the chirality effects and resulted in similar aggregation behavior for both the SWNT samples. Molecular modeling results enumerated key differences in surfactant conformation on SWNT surfaces and identified interaction energy changes between the two chiralities to delineate aggregation mechanisms. The stability of SWNTs increased in the presence of SRHA under 10 mM monovalent and mixed electrolyte conditions. The results suggest that change in chirality can overcome surfactant stabilization of semiconducting SWNTs. SWNT stability can also be strongly influenced by the anionic surfactant structure.

Research paper thumbnail of Fate of single walled carbon nanotubes in wetland ecosystems

Environ. Sci.: Nano, 2014

Research paper thumbnail of Control of Transcriptional Repression of the Vitellogenin Receptor Gene in Largemouth Bass (Micropterus Salmoides) by Select Estrogen Receptors Isotypes

Toxicological Sciences, 2014

The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor func... more The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor functions to incorporate vitellogenin (Vtg), a macromolecule synthesized and released from the liver in the bloodstream, into oocytes where it is processed into yolk. Although studies have focused on the functional role of Vtgr in fish, the mechanistic control of this gene is still unexplored. Here we report the identification and analysis of the first piscine 5 regulatory region of the vtgr gene which was cloned from largemouth bass (Micropterus salmoides). Using this putative promoter sequence, we investigated a role for hormones, including insulin and 17␤-estradiol (E 2 ), in transcriptional regulation through cell-based reporter assays. No effect of insulin was observed, however, E 2 was able to repress transcriptional activity of the vtgr promoter through select estrogen receptor subtypes, Esr1 and Esr2a but not Esr2b. Electrophoretic mobility shift assay demonstrated that Esr1 likely interacts with the vtgr promoter region through half ERE and/or SP1 sites, in part. Finally we also show that ethinylestradiol (EE 2 ), but not bisphenol-A (BPA), represses promoter activity similarly to E 2 . These results reveal for the first time that the Esr1 isoform may play an inhibitory role in the expression of LMB vtgr mRNA under the influence of E 2 , and potent estrogens such as EE 2 . In addition, this new evidence suggests that vtgr may be a target of select endocrine disrupting compounds through environmental exposures.

Research paper thumbnail of Environmental Carcinogenesis

Oncology, 2006

Environmental carcinogens are broadly defined as compounds that humans are exposed to through die... more Environmental carcinogens are broadly defined as compounds that humans are exposed to through diet, lifestyle, infectious agents, and occupation. They are considered as nongenetic factors that contribute to cancer risk. A subset of known and reasonably anticipated human carcinogens can be classified as environmental carcinogens and include such compounds as dioxins, metals, components of pesticides, the polyaromatic hydrocarbon (PAH) benzo(a)pyrene