Geeta Eick - Academia.edu (original) (raw)

Papers by Geeta Eick

Research paper thumbnail of Maternal hair cortisol concentrations across pregnancy and the early postpartum period in a Puerto Rican sample

American Journal of Human Biology, 2022

OBJECTIVE Hair cortisol is a noninvasive, long-term biomarker of human stress. Strengths and weak... more OBJECTIVE Hair cortisol is a noninvasive, long-term biomarker of human stress. Strengths and weaknesses of this biomarker as a proxy measure of perinatal stress are not yet well understood. Hair cortisol data were collected from pregnant women in Puerto Rico to investigate maternal cortisol level variance across pregnancy. METHODS In 2017, we recruited 86 pregnant women planning to birth at a large urban hospital. We aimed to collect four hair samples from each participant, one in each trimester and one in the postpartum period. RESULTS Median cortisol in the first trimester (n = 82) was 5.7 picograms/milligram (pg/mg) (range: 1.0-62.4). In the second, third, and postpartum periods, the medians were 6.8 pg/mg (1.0-69.5), (n = 46), 20.1 pg/mg (5.6-89.0), (n = 30), and 14.1 pg/mg (1.7-39.8), (n = 9), respectively. These medians disguise a 10-fold and 50-fold variability for two participants. Our sample sizes declined sharply when Hurricane Maria caused major disruptions in services and participants' lives. CONCLUSION Maternal hair cortisol concentrations were lower in the first and second trimester than the third trimester and early postpartum period. We also observed a wide range of variation in cortisol levels throughout pregnancy and in the postpartum period.

Research paper thumbnail of Prevalence of and factors associated with frailty and disability in older adults from China, Ghana, India, Mexico, Russia and South Africa

Maturitas, 2016

Highlights  Estimates are provided of the prevalence of frailty and disability in older adult po... more Highlights  Estimates are provided of the prevalence of frailty and disability in older adult populations in China, Ghana, India, Mexico, Russia and South Africa.  Their relationship of prevalence to socioeconomic factors in these six countries is also examined.  The study provides prevalence estimates in settings where data on frailty and disability among older adults on a country-wide scale may be unavailable.  Frailty and disability in older adult populations are compared across high-, middle-and lowincome countries.

Research paper thumbnail of Physical activity patterns and biomarkers of cardiovascular disease risk in hunter-gatherers

American journal of human biology : the official journal of the Human Biology Council, Jan 9, 2016

Time spent in moderate-to-vigorous physical activity (MVPA) is a strong predictor of cardiovascul... more Time spent in moderate-to-vigorous physical activity (MVPA) is a strong predictor of cardiovascular health, yet few humans living in industrialized societies meet current recommendations (150 min/week). Researchers have long suggested that human physiological requirements for aerobic exercise reflect an evolutionary shift to a hunting and gathering foraging strategy, and a recent transition to more sedentary lifestyles likely represents a mismatch with our past in terms of physical activity. The goal of this study is to explore this mismatch by characterizing MVPA and cardiovascular health in the Hadza, a modern hunting and gathering population living in Northern Tanzania. We measured MVPA using continuous heart rate monitoring in 46 participants recruited from two Hadza camps. As part of a larger survey of health in the Hadza, we measured blood pressure (n = 198) and biomarkers of cardiovascular health (n = 23) including C-reactive protein, cholesterol (Total, HDL, and LDL), and tr...

Research paper thumbnail of Validation of an Optimized ELISA for Quantitative Assessment of Epstein-Barr Virus Antibodies from Dried Blood Spots

Biodemography and social biology, 2016

Our objective was to validate a commercially available ELISA to measure antibody titers against E... more Our objective was to validate a commercially available ELISA to measure antibody titers against Epstein-Barr virus (EBV) in dried blood spots (DBS) to replace a previously validated assay for DBS that is no longer available. We evaluated the precision, reliability, and stability of the assay for the measurement of EBV antibodies in matched plasma, fingerprick DBS, and venous blood DBS samples from 208 individuals. Effects of hematocrit and DBS sample matrix on EBV antibody determination were also investigated, and the cutoff for seropositivity in DBS was determined. A conversion equation was derived to enable comparison of results generated using this method with the former DBS method. There was a high correlation between plasma and DBS EBV antibody titers (R(2) = 0.93) with very little bias (-0.07 based on Bland-Altman analysis). The assay showed good linearity and did not appear to be affected by the DBS matrix, and physiological hematocrit levels had no effect on assay performanc...

Research paper thumbnail of Dried Blood Spots

Research paper thumbnail of Nine new species of Dasineura (Diptera: Cecidomyiidae) from flowers of Australian Acacia (Mimosaceae)

Systematic Entomology, 2005

Thirteen species of Australian acacias are invasive plants in agricultural and native vegetation ... more Thirteen species of Australian acacias are invasive plants in agricultural and native vegetation areas of South Africa. Biological control programmes for Australian acacias in South Africa have been implemented and are aimed at suppressing reproductive vigour and, in some cases, vegetative growth of these weeds. Gall-forming midges are under consideration as potential biological control agents for invasive acacias in South Africa. Entomological surveys in southern Australia found a diverse cecidomyiid fauna associated with the buds, flowers and fruits of Acacia species. Nine new Dasineura species are described and two species, D. acaciaelongifoliae (Skuse) and D. dielsi Ru¨bsaamen, are redescribed. The newly described taxa are D. fistulosa sp.n., D. furcata sp.n., D. glauca sp.n., D. glomerata sp.n., D. oldfieldii sp.n., D. oshanesii sp.n., D. pilifera sp.n., D. rubiformis sp.n. and D. sulcata sp.n. All eleven species induce galls on ovaries and prevent the formation of fruit. Two general types of gall are caused. Type A comprises woody, tubular galls with larvae living inside ovaries (D. acaciaelongifoliae, D. dielsi, D. fistulosa, D. furcata, D. glauca, D. glomerata, D. oldfieldii). Type B includes soft-tissued, globose galls that belong to four subtypes: inflated, baglike, hairy galls with larvae living between ovaries (D. pilifera); pyriform, pubescent swellings with larvae living inside ovaries (D. rubiformis); globose, hairy, swellings with larvae living superficially on ovaries in ovoid chambers (D. oshanesii); and inconspicuous, glabrous swellings with larvae living superficially on ovaries in shallow groovelike chambers (D. sulcata). The gall types are associated with a particular pupation pattern. In type A galls, larvae pupate within larval chambers in galls, whereas in type B galls pupation takes place between ovaries in galls or in the soil beneath the host tree. Gall midges responsible for the same general gall type are morphologically related and differ from species causing the other gall type. Phylogenetic analysis of a 410 bp fragment of the mitochondrial cytochrome b gene supports the division of the gall midge species into two groups except for D. sulcata, which appears as a subgroup of the group causing type A galls. The interspecific divergence values in group A species were between 0.5 and 3.9% with intraspecific divergence estimates of 0-0.2%. Gall midges causing type B galls had interspecific divergence values of 4.6-7.3% and intraspecific divergence values of 0-3.7%. Closely related biology and morphology together with low cytochrome b divergence estimates suggest a more recent speciation in group A when compared with species of group B. Dasineura rubiformis and D. dielsi are proposed as potential biological control agents for Acacia mearnsii De Wild. and Acacia cyclops A. Cunn. ex G. Don, respectively, in South Africa due to their narrow host range and ability to form high population densities that reduce seed formation. Both species produce galls with low biomass, which makes them compatible with commercial exploitation of their host species in Africa.

Research paper thumbnail of Molecular Genetics of Gastroenteropancreatic Endocrine Tumors

Annals of the New York Academy of Sciences, 2004

Familial gastroenteropancreatic neuroendocrine tumors Although a majority of GEP NETs are sporadi... more Familial gastroenteropancreatic neuroendocrine tumors Although a majority of GEP NETs are sporadic, the molecular and clinical genetics of tumor susceptibility syndromes, in which GEP NETs may occur, have contributed to the understanding of tumorigenesis in these patients.

Research paper thumbnail of Evolutionary tuning of a key helix drove androgen selectivity

The genetic and biophysical mechanisms by which new protein functions evolve are central concerns... more The genetic and biophysical mechanisms by which new protein functions evolve are central concerns in evolutionary biology and molecular evolution. Despite much speculation, we know little about how protein function evolves. Here, we use ancestral proteins to trace the evolutionary history of ligand recognition in a sub-class of steroid receptors (SRs), an ancient family of ligand-regulated transcription factors that enable long-range cellular communication central to multicellular life. The most ancestral members of this family display promiscuous ligand binding due to their large ligand binding pockets, while more recently evolved SRs tend to have smaller cavities. Less obvious, however, are the forces driving the selectivity of highly similar ligands. A key example is the divergence between the progesterone and androgen receptors (PR, AR), which display a high degree of sequence similarity and yet display differential ligand preferences. This work uses the ancestral steroid recept...

Research paper thumbnail of Inflammation and central adiposity as mediators of depression and uncontrolled diabetes in the study on global AGEing and adult health (SAGE)

American Journal of Human Biology, 2020

Diabetes and depression are commonly present in the same individuals, suggesting the possibility ... more Diabetes and depression are commonly present in the same individuals, suggesting the possibility of underlying shared physiological processes. Inflammation, as assessed with the biomarker C‐reactive protein (CRP), has not consistently explained the observed relationship between diabetes and depression, although both are associated with inflammation and share proposed inflammatory mechanisms. Central adiposity has also been associated with both conditions, potentially by causing increased inflammation. This study uses the World Health Organization's Study on global AGEing and adult health (SAGE) Mexico Wave 1 biomarker data (n = 1831) to evaluate if inflammation and central adiposity mediate the relationship between depression and diabetes.

Research paper thumbnail of Eick Geeta (Orcid ID: 0000-0001-7512-3265) A Dried Blood Spot-Based Method to Measure Levels of Tartrate-Resistant Acid Phosphatase 5b (TRACP-5b), A Marker of Bone Resorption Running title: DBS Measurement of TRACP-5b

Objectives: A number of basic questions about bone biology have not been answered, including popu... more Objectives: A number of basic questions about bone biology have not been answered, including population differences in bone turnover. In part, this stems from the lack of validated minimally invasive biomarker techniques to measure bone formation and resorption in field-based population-level research. The present study addresses this gap by validating a fingerprick dried blood spot (fDBS) assay for tartrate-resistant acid phosphatase 5b (TRACP-5b), a well-defined biomarker of bone resorption and osteoclast number. Methods: We adapted a commercially available enzyme-linked immunosorbent assay (ELISA) kit from MyBiosource for the quantitative determination of TRACP-5b levels in serum and plasma for use with DBS. We used a rigorous process of assay modification and validation, including the use of a matched set of 189 adult plasma, fDBS, and venous DBS (vDBS) samples; parameters evaluated included precision, reliability, and analyte stability. Results: Plasma and DBS TRACP-5b concentr...

Research paper thumbnail of Current and future applications of biomarkers in samples collected through minimally invasive methods for cancer medicine and population‐based research

American Journal of Human Biology

Despite advances in cancer medicine and research, invasive and potentially risky procedures such ... more Despite advances in cancer medicine and research, invasive and potentially risky procedures such as biopsies, venous blood tests, imaging, colonoscopy, and pap smear tests are still primarily used for screening, staging, and assessing response to therapy. The development and interdisciplinary use of biomarkers from urine, feces, saliva, scent, and capillary blood collected with minimally invasive methods represents a potential opportunity for integration with biomarker analysis for cancers, both in clinical practice (e.g., in screening, treatment, and disease monitoring, and improved quality of life for patients) and population-based research (e.g., in epidemiology/public health, studies of social and environmental determinants, and evolutionary medicine). In this article, we review the scientific rationale, benefits, challenges, and potential opportunities for measuring cancer-related biomarkers in samples collected through minimally invasive methods.

Research paper thumbnail of Development and validation of an ELISA for a biomarker of thyroid dysfunction, thyroid peroxidase autoantibodies (TPO-Ab), in dried blood spots

Journal of Physiological Anthropology

Background The prevalence of allergic and autoimmune conditions has been steadily increasing in w... more Background The prevalence of allergic and autoimmune conditions has been steadily increasing in wealthy nations over the past century. One hypothesis put forward to explain this is the Old Friends Hypothesis, which posits that increased hygiene, urbanization, and lifestyle changes have reduced our exposure to parasites and microbes that we co-evolved with, resulting in immune dysregulation. However, research in traditionally living populations, who are exposed to greater parasite and pathogen loads such as those encountered during our evolution, is limited, in part due to a lack of minimally invasive, field-friendly biomarkers of autoimmune disorders. We therefore developed an ELISA to assess positivity for thyroid peroxidase autoantibody (TPO-Ab), an indicator of autoimmune thyroid disease, based on dried blood spot (DBS) samples. Results We used the Accubind anti-thyroid peroxidase test system to screen our validation samples comprising matched fingerprick DBS, venous DBS, and pla...

Research paper thumbnail of Motor Cortex Function in Symptomatic and Asymptomatic Individuals Following Mild Traumatic Brain Injury

Medicine & Science in Sports & Exercise

RESULTS: The SS significantly increased the contralateral hip flexion passive ROM (Pre = 64.70 ± ... more RESULTS: The SS significantly increased the contralateral hip flexion passive ROM (Pre = 64.70 ± 19.19o vs. Post = 73.48 ± 22.60o, p < 0.001). In addition, the isometric strength of the contralateral knee flexor significantly decreased (Pre = 326.63 ± 91.81 N vs. Post = 310.44 ± 92.08, p = 0.004). For both biceps femoris (p = 0.065) and semitendinosus (p = 0.083) muscles, there were decreasing trends toward significance for the normalized EMG amplitude. CONCLUSIONS: Prolonged unilateral SS intervention improved the contralateral hip flexion passive ROM but decreased the strength performance. In addition to the possible increased stretch tolerance, the high intensity and duration static stretches might have also induced the crossover inhibition of the spinal motoneurons, thereby reducing the neuromuscular performance of the contralateral muscle.

Research paper thumbnail of Validation of an enzyme‐linked immunoassay assay for osteocalcin, a marker of bone formation, in dried blood spots

American Journal of Human Biology

Research paper thumbnail of Functional Measures of Sarcopenia: Prevalence, and Associations with Functional Disability in 10,892 Adults Aged 65 Years and Over from Six Lower- and Middle-Income Countries

Calcified Tissue International

Identification of sarcopenia in lower- and middle-income countries (LMICs) is limited by access t... more Identification of sarcopenia in lower- and middle-income countries (LMICs) is limited by access to technologies that assess muscle mass. We investigated associations between two functional measures of sarcopenia, grip strength and gait speed (GS), with functional disability in adults from six LMICs. Data were extracted from the World Health Organization (WHO) Study on global AGEing and adult health Wave 1 (2007–2010) for adults (≥ 65 years) from China, Mexico, Ghana, India, Russia and South Africa (n = 10,892, 52.8% women). We calculated country-specific prevalence of low grip strength, slow GS (≤ 0.8 m/s), and both measures combined. Using multivariable negative binomial regression, we separately assessed associations between low grip strength, slow GS, and both measures combined, with the WHO Disability Assessment Schedule 2.0, accounting for selected socioeconomic factors. In women, low grip strength ranged from 7 in South Africa to 51% in India; in men, it ranged from 17 in Russia to 51% in Mexico. Country-specific proportions of slow GS ranged from 77 in Russia, to 33% in China. The concomitant presence of both was the lowest in South Africa and the highest in India (12.3% vs. 33%). Independent of age, those with both low grip strength and slow GS had between 1.2- and 1.5-fold worse functional disability scores, independent of comorbidities, low education, and low wealth (all country-dependent). Low grip strength, slow GS, and the combination of both, were all associated with higher levels of functional disability, thus indicating these objective measures offer a reasonably robust estimate for potential poor health outcomes.

Research paper thumbnail of Soil-transmitted helminth infection and intestinal inflammation among the Shuar of Amazonian Ecuador

American Journal of Physical Anthropology

Research paper thumbnail of A dried blood spot‐based method to measure levels of tartrate‐resistant acid phosphatase 5b (TRACP‐5b), a marker of bone resorption

American Journal of Human Biology

Objectives: A number of basic questions about bone biology have not been answered, including popu... more Objectives: A number of basic questions about bone biology have not been answered, including population differences in bone turnover. In part, this stems from the lack of validated minimally invasive biomarker techniques to measure bone formation and resorption in field-based population-level research. The present study addresses this gap by validating a fingerprick dried blood spot (fDBS) assay for tartrate-resistant acid phosphatase 5b (TRACP-5b), a well-defined biomarker of bone resorption and osteoclast number. Methods: We adapted a commercially available enzyme-linked immunosorbent assay (ELISA) kit from MyBiosource for the quantitative determination of TRACP-5b levels in serum and plasma for use with DBS. We used a rigorous process of assay modification and validation, including the use of a matched set of 189 adult plasma, fDBS, and venous DBS (vDBS) samples; parameters evaluated included precision, reliability, and analyte stability. Results: Plasma and DBS TRACP-5b concentrations showed a linear relationship. There were no systematic differences in TRACP-5b levels in fDBS and vDBS, indicating no significant differences in TRACP-5b distribution between capillary and venous blood. Parallelism and spike-and-recovery results indicated that matrix factors in DBS do not interfere with measurement of TRACP-5b levels from DBS using the validated kit. Intra-and interassay CVs were 5.0% and 12.1%, respectively. DBS samples should preferably be stored frozen but controlled room temperature storage for up to a month may be acceptable. Conclusions: This DBS-based ELISA assay adds to the methodological toolkit available to human biologists and will facilitate research on bone turnover in population studies. 1 | INTRODUCTION Bone, which comprises mineralized connective tissue, is a highly dynamic organ that is continually undergoing remodeling, with bone resorption by osteoclasts and bone formation by osteoblasts (Sims & Martin, 2014). The balance between bone formation and resorption changes throughout life in ways that can be informative about life history events, providing a window into the lived experience of the individual since bone turnover is shaped not only by genetics, but also mechanical forces, dietary factors, and other aspects of lifestyle and environment. There is, therefore, broad interest in biological anthropology in uncovering the specific factors that influence bone turnover throughout the life course.

Research paper thumbnail of Tradeoffs between immune function and childhood growth among Amazonian forager-horticulturalists

Proceedings of the National Academy of Sciences of the United States of America, Apr 9, 2018

Immune function is an energetically costly physiological activity that potentially diverts calori... more Immune function is an energetically costly physiological activity that potentially diverts calories away from less immediately essential life tasks. Among developing organisms, the allocation of energy toward immune function may lead to tradeoffs with physical growth, particularly in high-pathogen, low-resource environments. The present study tests this hypothesis across diverse timeframes, branches of immunity, and conditions of energy availability among humans. Using a prospective mixed-longitudinal design, we collected anthropometric and blood immune biomarker data from 261 Amazonian forager-horticulturalist Shuar children (age 4-11 y old). This strategy provided baseline measures of participant stature, s.c. body fat, and humoral and cell-mediated immune activity as well as subsample longitudinal measures of linear growth (1 wk, 3 mo, 20 mo) and acute inflammation. Multilevel analyses demonstrate consistent negative effects of immune function on growth, with children experiencin...

Research paper thumbnail of Evaluating minimally invasive sample collection methods for telomere length measurement

American Journal of Human Biology

Objectives: Telomere length (TL) is a biomarker of aging and age-related decline. Although venous... more Objectives: Telomere length (TL) is a biomarker of aging and age-related decline. Although venous blood is considered the "gold standard" for TL measurement, its collection is often not feasible or desired in nonclinical settings. Saliva and dried blood spots (DBS) have been used as alternatives when venipuncture cannot be performed. However, it is not known whether these sample types yield TL measurements comparable to those obtained from venous blood. We sought to determine whether different samples from the same individual yield comparable TL measurements. Methods: We extracted DNA from matched buffy coat, saliva (Oragene and Oasis), and DBS (venous and capillary) samples from 40 women aged 18-77 years. We used the monochrome multiplex qPCR (MMQPCR) assay to measure TL in all sample types for each participant and applied quality control measures to retain only highquality samples for analysis. We then compared TL from buffy coat and saliva to examine how these measurements differ and to test if TL is correlated across sample types. Results: TL differed significantly across buffy coat, Oragene saliva, and Oasis saliva samples. TL from buffy coat and Oragene saliva was moderately correlated (q 5 0.48, P 5 .002) and the most similar in size. Oasis saliva TL was not correlated with buffy coat or Oragene saliva TL, and was the shortest. DBS DNA yields were inadequate for TL measurement using the MMQPCR assay. Conclusions: Using a matched dataset we demonstrate that sample type significantly influences the TL measurement obtained using the MMQPCR assay.

Research paper thumbnail of Cis -regulatory evolution in a wild primate: Infection-associated genetic variation drives differential expression of MHC-DQA1 in vitro

Molecular Ecology

Few studies have combined genetic association analyses with functional characterization of infect... more Few studies have combined genetic association analyses with functional characterization of infection-associated SNPs in natural populations of non-human primates. Here, we investigate the relationship between host genetic variation, parasitism, and natural selection in a population of red colobus (Procolobus rufomitratus tephrosceles) in Kibale National Park, Uganda. We collected parasitological, cellular, and genomic data to test the following hypotheses: 1) MHC-DQA1 regulatory genetic variation is associated with control of whipworm (Trichuris) infection in a natural population of red colobus; 2) infection-associated SNPs are functional in driving differential gene expression in-vitro; and 3) balancing selection has shaped patterns of variation in the MHC-DQA1 promoter. We identified two SNPs in the MHC-DQA1 promoter, both in transcription factor binding sites, and both of which are associated with decreased control of Trichuris infection. We characterized the function of both SNPs by testing differences in gene

Research paper thumbnail of Maternal hair cortisol concentrations across pregnancy and the early postpartum period in a Puerto Rican sample

American Journal of Human Biology, 2022

OBJECTIVE Hair cortisol is a noninvasive, long-term biomarker of human stress. Strengths and weak... more OBJECTIVE Hair cortisol is a noninvasive, long-term biomarker of human stress. Strengths and weaknesses of this biomarker as a proxy measure of perinatal stress are not yet well understood. Hair cortisol data were collected from pregnant women in Puerto Rico to investigate maternal cortisol level variance across pregnancy. METHODS In 2017, we recruited 86 pregnant women planning to birth at a large urban hospital. We aimed to collect four hair samples from each participant, one in each trimester and one in the postpartum period. RESULTS Median cortisol in the first trimester (n = 82) was 5.7 picograms/milligram (pg/mg) (range: 1.0-62.4). In the second, third, and postpartum periods, the medians were 6.8 pg/mg (1.0-69.5), (n = 46), 20.1 pg/mg (5.6-89.0), (n = 30), and 14.1 pg/mg (1.7-39.8), (n = 9), respectively. These medians disguise a 10-fold and 50-fold variability for two participants. Our sample sizes declined sharply when Hurricane Maria caused major disruptions in services and participants' lives. CONCLUSION Maternal hair cortisol concentrations were lower in the first and second trimester than the third trimester and early postpartum period. We also observed a wide range of variation in cortisol levels throughout pregnancy and in the postpartum period.

Research paper thumbnail of Prevalence of and factors associated with frailty and disability in older adults from China, Ghana, India, Mexico, Russia and South Africa

Maturitas, 2016

Highlights  Estimates are provided of the prevalence of frailty and disability in older adult po... more Highlights  Estimates are provided of the prevalence of frailty and disability in older adult populations in China, Ghana, India, Mexico, Russia and South Africa.  Their relationship of prevalence to socioeconomic factors in these six countries is also examined.  The study provides prevalence estimates in settings where data on frailty and disability among older adults on a country-wide scale may be unavailable.  Frailty and disability in older adult populations are compared across high-, middle-and lowincome countries.

Research paper thumbnail of Physical activity patterns and biomarkers of cardiovascular disease risk in hunter-gatherers

American journal of human biology : the official journal of the Human Biology Council, Jan 9, 2016

Time spent in moderate-to-vigorous physical activity (MVPA) is a strong predictor of cardiovascul... more Time spent in moderate-to-vigorous physical activity (MVPA) is a strong predictor of cardiovascular health, yet few humans living in industrialized societies meet current recommendations (150 min/week). Researchers have long suggested that human physiological requirements for aerobic exercise reflect an evolutionary shift to a hunting and gathering foraging strategy, and a recent transition to more sedentary lifestyles likely represents a mismatch with our past in terms of physical activity. The goal of this study is to explore this mismatch by characterizing MVPA and cardiovascular health in the Hadza, a modern hunting and gathering population living in Northern Tanzania. We measured MVPA using continuous heart rate monitoring in 46 participants recruited from two Hadza camps. As part of a larger survey of health in the Hadza, we measured blood pressure (n = 198) and biomarkers of cardiovascular health (n = 23) including C-reactive protein, cholesterol (Total, HDL, and LDL), and tr...

Research paper thumbnail of Validation of an Optimized ELISA for Quantitative Assessment of Epstein-Barr Virus Antibodies from Dried Blood Spots

Biodemography and social biology, 2016

Our objective was to validate a commercially available ELISA to measure antibody titers against E... more Our objective was to validate a commercially available ELISA to measure antibody titers against Epstein-Barr virus (EBV) in dried blood spots (DBS) to replace a previously validated assay for DBS that is no longer available. We evaluated the precision, reliability, and stability of the assay for the measurement of EBV antibodies in matched plasma, fingerprick DBS, and venous blood DBS samples from 208 individuals. Effects of hematocrit and DBS sample matrix on EBV antibody determination were also investigated, and the cutoff for seropositivity in DBS was determined. A conversion equation was derived to enable comparison of results generated using this method with the former DBS method. There was a high correlation between plasma and DBS EBV antibody titers (R(2) = 0.93) with very little bias (-0.07 based on Bland-Altman analysis). The assay showed good linearity and did not appear to be affected by the DBS matrix, and physiological hematocrit levels had no effect on assay performanc...

Research paper thumbnail of Dried Blood Spots

Research paper thumbnail of Nine new species of Dasineura (Diptera: Cecidomyiidae) from flowers of Australian Acacia (Mimosaceae)

Systematic Entomology, 2005

Thirteen species of Australian acacias are invasive plants in agricultural and native vegetation ... more Thirteen species of Australian acacias are invasive plants in agricultural and native vegetation areas of South Africa. Biological control programmes for Australian acacias in South Africa have been implemented and are aimed at suppressing reproductive vigour and, in some cases, vegetative growth of these weeds. Gall-forming midges are under consideration as potential biological control agents for invasive acacias in South Africa. Entomological surveys in southern Australia found a diverse cecidomyiid fauna associated with the buds, flowers and fruits of Acacia species. Nine new Dasineura species are described and two species, D. acaciaelongifoliae (Skuse) and D. dielsi Ru¨bsaamen, are redescribed. The newly described taxa are D. fistulosa sp.n., D. furcata sp.n., D. glauca sp.n., D. glomerata sp.n., D. oldfieldii sp.n., D. oshanesii sp.n., D. pilifera sp.n., D. rubiformis sp.n. and D. sulcata sp.n. All eleven species induce galls on ovaries and prevent the formation of fruit. Two general types of gall are caused. Type A comprises woody, tubular galls with larvae living inside ovaries (D. acaciaelongifoliae, D. dielsi, D. fistulosa, D. furcata, D. glauca, D. glomerata, D. oldfieldii). Type B includes soft-tissued, globose galls that belong to four subtypes: inflated, baglike, hairy galls with larvae living between ovaries (D. pilifera); pyriform, pubescent swellings with larvae living inside ovaries (D. rubiformis); globose, hairy, swellings with larvae living superficially on ovaries in ovoid chambers (D. oshanesii); and inconspicuous, glabrous swellings with larvae living superficially on ovaries in shallow groovelike chambers (D. sulcata). The gall types are associated with a particular pupation pattern. In type A galls, larvae pupate within larval chambers in galls, whereas in type B galls pupation takes place between ovaries in galls or in the soil beneath the host tree. Gall midges responsible for the same general gall type are morphologically related and differ from species causing the other gall type. Phylogenetic analysis of a 410 bp fragment of the mitochondrial cytochrome b gene supports the division of the gall midge species into two groups except for D. sulcata, which appears as a subgroup of the group causing type A galls. The interspecific divergence values in group A species were between 0.5 and 3.9% with intraspecific divergence estimates of 0-0.2%. Gall midges causing type B galls had interspecific divergence values of 4.6-7.3% and intraspecific divergence values of 0-3.7%. Closely related biology and morphology together with low cytochrome b divergence estimates suggest a more recent speciation in group A when compared with species of group B. Dasineura rubiformis and D. dielsi are proposed as potential biological control agents for Acacia mearnsii De Wild. and Acacia cyclops A. Cunn. ex G. Don, respectively, in South Africa due to their narrow host range and ability to form high population densities that reduce seed formation. Both species produce galls with low biomass, which makes them compatible with commercial exploitation of their host species in Africa.

Research paper thumbnail of Molecular Genetics of Gastroenteropancreatic Endocrine Tumors

Annals of the New York Academy of Sciences, 2004

Familial gastroenteropancreatic neuroendocrine tumors Although a majority of GEP NETs are sporadi... more Familial gastroenteropancreatic neuroendocrine tumors Although a majority of GEP NETs are sporadic, the molecular and clinical genetics of tumor susceptibility syndromes, in which GEP NETs may occur, have contributed to the understanding of tumorigenesis in these patients.

Research paper thumbnail of Evolutionary tuning of a key helix drove androgen selectivity

The genetic and biophysical mechanisms by which new protein functions evolve are central concerns... more The genetic and biophysical mechanisms by which new protein functions evolve are central concerns in evolutionary biology and molecular evolution. Despite much speculation, we know little about how protein function evolves. Here, we use ancestral proteins to trace the evolutionary history of ligand recognition in a sub-class of steroid receptors (SRs), an ancient family of ligand-regulated transcription factors that enable long-range cellular communication central to multicellular life. The most ancestral members of this family display promiscuous ligand binding due to their large ligand binding pockets, while more recently evolved SRs tend to have smaller cavities. Less obvious, however, are the forces driving the selectivity of highly similar ligands. A key example is the divergence between the progesterone and androgen receptors (PR, AR), which display a high degree of sequence similarity and yet display differential ligand preferences. This work uses the ancestral steroid recept...

Research paper thumbnail of Inflammation and central adiposity as mediators of depression and uncontrolled diabetes in the study on global AGEing and adult health (SAGE)

American Journal of Human Biology, 2020

Diabetes and depression are commonly present in the same individuals, suggesting the possibility ... more Diabetes and depression are commonly present in the same individuals, suggesting the possibility of underlying shared physiological processes. Inflammation, as assessed with the biomarker C‐reactive protein (CRP), has not consistently explained the observed relationship between diabetes and depression, although both are associated with inflammation and share proposed inflammatory mechanisms. Central adiposity has also been associated with both conditions, potentially by causing increased inflammation. This study uses the World Health Organization's Study on global AGEing and adult health (SAGE) Mexico Wave 1 biomarker data (n = 1831) to evaluate if inflammation and central adiposity mediate the relationship between depression and diabetes.

Research paper thumbnail of Eick Geeta (Orcid ID: 0000-0001-7512-3265) A Dried Blood Spot-Based Method to Measure Levels of Tartrate-Resistant Acid Phosphatase 5b (TRACP-5b), A Marker of Bone Resorption Running title: DBS Measurement of TRACP-5b

Objectives: A number of basic questions about bone biology have not been answered, including popu... more Objectives: A number of basic questions about bone biology have not been answered, including population differences in bone turnover. In part, this stems from the lack of validated minimally invasive biomarker techniques to measure bone formation and resorption in field-based population-level research. The present study addresses this gap by validating a fingerprick dried blood spot (fDBS) assay for tartrate-resistant acid phosphatase 5b (TRACP-5b), a well-defined biomarker of bone resorption and osteoclast number. Methods: We adapted a commercially available enzyme-linked immunosorbent assay (ELISA) kit from MyBiosource for the quantitative determination of TRACP-5b levels in serum and plasma for use with DBS. We used a rigorous process of assay modification and validation, including the use of a matched set of 189 adult plasma, fDBS, and venous DBS (vDBS) samples; parameters evaluated included precision, reliability, and analyte stability. Results: Plasma and DBS TRACP-5b concentr...

Research paper thumbnail of Current and future applications of biomarkers in samples collected through minimally invasive methods for cancer medicine and population‐based research

American Journal of Human Biology

Despite advances in cancer medicine and research, invasive and potentially risky procedures such ... more Despite advances in cancer medicine and research, invasive and potentially risky procedures such as biopsies, venous blood tests, imaging, colonoscopy, and pap smear tests are still primarily used for screening, staging, and assessing response to therapy. The development and interdisciplinary use of biomarkers from urine, feces, saliva, scent, and capillary blood collected with minimally invasive methods represents a potential opportunity for integration with biomarker analysis for cancers, both in clinical practice (e.g., in screening, treatment, and disease monitoring, and improved quality of life for patients) and population-based research (e.g., in epidemiology/public health, studies of social and environmental determinants, and evolutionary medicine). In this article, we review the scientific rationale, benefits, challenges, and potential opportunities for measuring cancer-related biomarkers in samples collected through minimally invasive methods.

Research paper thumbnail of Development and validation of an ELISA for a biomarker of thyroid dysfunction, thyroid peroxidase autoantibodies (TPO-Ab), in dried blood spots

Journal of Physiological Anthropology

Background The prevalence of allergic and autoimmune conditions has been steadily increasing in w... more Background The prevalence of allergic and autoimmune conditions has been steadily increasing in wealthy nations over the past century. One hypothesis put forward to explain this is the Old Friends Hypothesis, which posits that increased hygiene, urbanization, and lifestyle changes have reduced our exposure to parasites and microbes that we co-evolved with, resulting in immune dysregulation. However, research in traditionally living populations, who are exposed to greater parasite and pathogen loads such as those encountered during our evolution, is limited, in part due to a lack of minimally invasive, field-friendly biomarkers of autoimmune disorders. We therefore developed an ELISA to assess positivity for thyroid peroxidase autoantibody (TPO-Ab), an indicator of autoimmune thyroid disease, based on dried blood spot (DBS) samples. Results We used the Accubind anti-thyroid peroxidase test system to screen our validation samples comprising matched fingerprick DBS, venous DBS, and pla...

Research paper thumbnail of Motor Cortex Function in Symptomatic and Asymptomatic Individuals Following Mild Traumatic Brain Injury

Medicine & Science in Sports & Exercise

RESULTS: The SS significantly increased the contralateral hip flexion passive ROM (Pre = 64.70 ± ... more RESULTS: The SS significantly increased the contralateral hip flexion passive ROM (Pre = 64.70 ± 19.19o vs. Post = 73.48 ± 22.60o, p < 0.001). In addition, the isometric strength of the contralateral knee flexor significantly decreased (Pre = 326.63 ± 91.81 N vs. Post = 310.44 ± 92.08, p = 0.004). For both biceps femoris (p = 0.065) and semitendinosus (p = 0.083) muscles, there were decreasing trends toward significance for the normalized EMG amplitude. CONCLUSIONS: Prolonged unilateral SS intervention improved the contralateral hip flexion passive ROM but decreased the strength performance. In addition to the possible increased stretch tolerance, the high intensity and duration static stretches might have also induced the crossover inhibition of the spinal motoneurons, thereby reducing the neuromuscular performance of the contralateral muscle.

Research paper thumbnail of Validation of an enzyme‐linked immunoassay assay for osteocalcin, a marker of bone formation, in dried blood spots

American Journal of Human Biology

Research paper thumbnail of Functional Measures of Sarcopenia: Prevalence, and Associations with Functional Disability in 10,892 Adults Aged 65 Years and Over from Six Lower- and Middle-Income Countries

Calcified Tissue International

Identification of sarcopenia in lower- and middle-income countries (LMICs) is limited by access t... more Identification of sarcopenia in lower- and middle-income countries (LMICs) is limited by access to technologies that assess muscle mass. We investigated associations between two functional measures of sarcopenia, grip strength and gait speed (GS), with functional disability in adults from six LMICs. Data were extracted from the World Health Organization (WHO) Study on global AGEing and adult health Wave 1 (2007–2010) for adults (≥ 65 years) from China, Mexico, Ghana, India, Russia and South Africa (n = 10,892, 52.8% women). We calculated country-specific prevalence of low grip strength, slow GS (≤ 0.8 m/s), and both measures combined. Using multivariable negative binomial regression, we separately assessed associations between low grip strength, slow GS, and both measures combined, with the WHO Disability Assessment Schedule 2.0, accounting for selected socioeconomic factors. In women, low grip strength ranged from 7 in South Africa to 51% in India; in men, it ranged from 17 in Russia to 51% in Mexico. Country-specific proportions of slow GS ranged from 77 in Russia, to 33% in China. The concomitant presence of both was the lowest in South Africa and the highest in India (12.3% vs. 33%). Independent of age, those with both low grip strength and slow GS had between 1.2- and 1.5-fold worse functional disability scores, independent of comorbidities, low education, and low wealth (all country-dependent). Low grip strength, slow GS, and the combination of both, were all associated with higher levels of functional disability, thus indicating these objective measures offer a reasonably robust estimate for potential poor health outcomes.

Research paper thumbnail of Soil-transmitted helminth infection and intestinal inflammation among the Shuar of Amazonian Ecuador

American Journal of Physical Anthropology

Research paper thumbnail of A dried blood spot‐based method to measure levels of tartrate‐resistant acid phosphatase 5b (TRACP‐5b), a marker of bone resorption

American Journal of Human Biology

Objectives: A number of basic questions about bone biology have not been answered, including popu... more Objectives: A number of basic questions about bone biology have not been answered, including population differences in bone turnover. In part, this stems from the lack of validated minimally invasive biomarker techniques to measure bone formation and resorption in field-based population-level research. The present study addresses this gap by validating a fingerprick dried blood spot (fDBS) assay for tartrate-resistant acid phosphatase 5b (TRACP-5b), a well-defined biomarker of bone resorption and osteoclast number. Methods: We adapted a commercially available enzyme-linked immunosorbent assay (ELISA) kit from MyBiosource for the quantitative determination of TRACP-5b levels in serum and plasma for use with DBS. We used a rigorous process of assay modification and validation, including the use of a matched set of 189 adult plasma, fDBS, and venous DBS (vDBS) samples; parameters evaluated included precision, reliability, and analyte stability. Results: Plasma and DBS TRACP-5b concentrations showed a linear relationship. There were no systematic differences in TRACP-5b levels in fDBS and vDBS, indicating no significant differences in TRACP-5b distribution between capillary and venous blood. Parallelism and spike-and-recovery results indicated that matrix factors in DBS do not interfere with measurement of TRACP-5b levels from DBS using the validated kit. Intra-and interassay CVs were 5.0% and 12.1%, respectively. DBS samples should preferably be stored frozen but controlled room temperature storage for up to a month may be acceptable. Conclusions: This DBS-based ELISA assay adds to the methodological toolkit available to human biologists and will facilitate research on bone turnover in population studies. 1 | INTRODUCTION Bone, which comprises mineralized connective tissue, is a highly dynamic organ that is continually undergoing remodeling, with bone resorption by osteoclasts and bone formation by osteoblasts (Sims & Martin, 2014). The balance between bone formation and resorption changes throughout life in ways that can be informative about life history events, providing a window into the lived experience of the individual since bone turnover is shaped not only by genetics, but also mechanical forces, dietary factors, and other aspects of lifestyle and environment. There is, therefore, broad interest in biological anthropology in uncovering the specific factors that influence bone turnover throughout the life course.

Research paper thumbnail of Tradeoffs between immune function and childhood growth among Amazonian forager-horticulturalists

Proceedings of the National Academy of Sciences of the United States of America, Apr 9, 2018

Immune function is an energetically costly physiological activity that potentially diverts calori... more Immune function is an energetically costly physiological activity that potentially diverts calories away from less immediately essential life tasks. Among developing organisms, the allocation of energy toward immune function may lead to tradeoffs with physical growth, particularly in high-pathogen, low-resource environments. The present study tests this hypothesis across diverse timeframes, branches of immunity, and conditions of energy availability among humans. Using a prospective mixed-longitudinal design, we collected anthropometric and blood immune biomarker data from 261 Amazonian forager-horticulturalist Shuar children (age 4-11 y old). This strategy provided baseline measures of participant stature, s.c. body fat, and humoral and cell-mediated immune activity as well as subsample longitudinal measures of linear growth (1 wk, 3 mo, 20 mo) and acute inflammation. Multilevel analyses demonstrate consistent negative effects of immune function on growth, with children experiencin...

Research paper thumbnail of Evaluating minimally invasive sample collection methods for telomere length measurement

American Journal of Human Biology

Objectives: Telomere length (TL) is a biomarker of aging and age-related decline. Although venous... more Objectives: Telomere length (TL) is a biomarker of aging and age-related decline. Although venous blood is considered the "gold standard" for TL measurement, its collection is often not feasible or desired in nonclinical settings. Saliva and dried blood spots (DBS) have been used as alternatives when venipuncture cannot be performed. However, it is not known whether these sample types yield TL measurements comparable to those obtained from venous blood. We sought to determine whether different samples from the same individual yield comparable TL measurements. Methods: We extracted DNA from matched buffy coat, saliva (Oragene and Oasis), and DBS (venous and capillary) samples from 40 women aged 18-77 years. We used the monochrome multiplex qPCR (MMQPCR) assay to measure TL in all sample types for each participant and applied quality control measures to retain only highquality samples for analysis. We then compared TL from buffy coat and saliva to examine how these measurements differ and to test if TL is correlated across sample types. Results: TL differed significantly across buffy coat, Oragene saliva, and Oasis saliva samples. TL from buffy coat and Oragene saliva was moderately correlated (q 5 0.48, P 5 .002) and the most similar in size. Oasis saliva TL was not correlated with buffy coat or Oragene saliva TL, and was the shortest. DBS DNA yields were inadequate for TL measurement using the MMQPCR assay. Conclusions: Using a matched dataset we demonstrate that sample type significantly influences the TL measurement obtained using the MMQPCR assay.

Research paper thumbnail of Cis -regulatory evolution in a wild primate: Infection-associated genetic variation drives differential expression of MHC-DQA1 in vitro

Molecular Ecology

Few studies have combined genetic association analyses with functional characterization of infect... more Few studies have combined genetic association analyses with functional characterization of infection-associated SNPs in natural populations of non-human primates. Here, we investigate the relationship between host genetic variation, parasitism, and natural selection in a population of red colobus (Procolobus rufomitratus tephrosceles) in Kibale National Park, Uganda. We collected parasitological, cellular, and genomic data to test the following hypotheses: 1) MHC-DQA1 regulatory genetic variation is associated with control of whipworm (Trichuris) infection in a natural population of red colobus; 2) infection-associated SNPs are functional in driving differential gene expression in-vitro; and 3) balancing selection has shaped patterns of variation in the MHC-DQA1 promoter. We identified two SNPs in the MHC-DQA1 promoter, both in transcription factor binding sites, and both of which are associated with decreased control of Trichuris infection. We characterized the function of both SNPs by testing differences in gene