2005 Faculty Research Interests
Steven A. Abrams, M.D.
Dr. Abrams' research focuses on the mineral nutritional needs of infants, children and adolescents. His first major area of interest is in calcium and bone mineral requirements of children. The goal of this work is to evaluate methods for optimizing bone mass in childhood, using stable isotopes to measure calcium absorption and bone kinetics. His second area of interest is in identifying the optimal forms and amount of iron and zinc to provide to small children, especially those who live in developing countries. In these countries, iron deficiency anemia and zinc deficiency are extremely common and strategies must be developed for fortifying food sources and providing complementary foods with adequate amounts of bioavailable minerals. His team frequently travels to other countries to assess these issues and assists in developing research programs using iron and zinc stable isotopes.
Cheryl B. Anderson, Ph.D.
Dr. Anderson’s research is aimed at promoting regular physical activity through understanding its determinants, including self-identity as a motivational factor in health behavior. A primary focus is the description and measurement of athletic identity and its relation to physical activity in children, adolescents, and parents, as well as factors that contribute to identity formation, stability, and change. Another focus of her research is the development of psychometrically valid and reliable measurement instruments of attitudes and behaviors, as well as the statistical evaluation of existing measurement instruments that are used in behavioral research.
Janice Baranowski, M.P.H., R.D., L.D.
Ms. Baranowski is interested in dietary and physical activity health promotion, and obesity and chronic disease prevention among children and their families. She designs, implements and evaluates programs to help children and their families change dietary and physical activity behaviors. Ms. Baranowski currently is co-principal investigator on a diet and physical activity badge program for Boy Scouts, an investigation of influences on availability of fruit, juice and vegetables in the home, and a diabetes prevention trial among middle-school students.
Tom Baranowski, Ph.D.
Dr. Baranowski conducts research on obesity and chronic disease prevention among children and their families. Toward this end, he develops and tests new measures of diet and physical activity and their correlates; assesses correlates of diet and physical activity; and designs, implements and evaluates programs to help children and their families change dietary and physical activity behaviors. He currently is Principal Investigator on the design and evaluation of a middle school diabetes prevention trial; design and evaluation of interactive multimedia games for lifestyle change for diabetes prevention for middle school students; a survey on food shopping and home food management practices as correlates of home availability of fruit and vegetables; and research on the sensitivity to the bitter taste in fruit and vegetables (PROP) in relation to dietary intake and obesity among children.
Dennis M. Bier, M.D.
Dr. Bier's primary research interest is the integrated regulation of interorgan transport of metabolic fuels; specifically, substrate and hormonal regulation of the macronutrient fuels, glucose, fatty acids, ketones, and proteins/amino acids. This work has contributed broadly to the endocrine, nutritional and physiological regulation of endogenous fuel availability for biochemical and nutritional functions in otherwise healthy infants born very prematurely, normal newborn infants born at term, growing children, maturing adolescents, and healthy young and elderly adults. Further, his laboratory has helped both define and refine assessment of the altered metabolic fates of ingested, exogenous fuels under various pathophysiological circumstances that detrimentally change nutritional homeostasis, for example the metabolic fuel derangements accompanying diabetes and renal failure. In these endeavors, his laboratory has developed and employed a wide variety of stable isotope tracer kinetic methods that have now become the standards in the field for quantifying substrate flux, metabolism, precursor-product relationships, and irreversible oxidation to exhaled or excreted end products.
Molly S. Bray, PhD.
Dr. Bray’s research is focused on understanding the genetic basis of obesity using both statistical and experimental models, and her laboratory is currently involved in genotyping several large cohorts of obese and lean individuals for candidate polymorphisms within genes related to obesity and cardiovascular disease, using advanced high throughput genotyping techniques. Dr. Bray’s goal is to identify genetic and molecular mechanisms for the development of obesity and response to obesity treatments, including exercise, diet, and obesity surgery. Dr. Bray currently heads a large exercise training study in a multi-racial population of students from the University of Houston that is designed to elucidate genes that mediate the physiological changes that occur following physical activity. Work in Dr. Bray’s lab also includes the investigation of mechanisms by which altered sleep patterns (the “24-hour” lifestyle) may contribute to the accumulation of body fat. Her group has demonstrated the presence of a fully functional circadian clock within the adipocyte, and future research will identify the genes and metabolic functions that are regulated by this clock mechanism, with the ultimate goal of determining whether disease states precede (and therefore produce) or follow (and therefore are a consequence of) alterations in the clock mechanism. This research will provide important insight into the role of intrinsic clocks within adipose tissue in the development of obesity.
Douglas G. Burrin, Ph.D.
Dr. Burrin’s major research goal is to elucidate the critical cellular and hormonal signals that mediate the stimulatory effects of enteral nutrition on the growth and function of the neonatal intestine. Current studies are aimed at establishing the physiological and clinical significance of enteral nutrition and GLP-2 and how they impact intestinal nutrient metabolism in his neonatal pig model. Dr. Burrin is using isotope tracers coupled with arteriovenous organ balance and blood flow measurements in neonatal pigs to quantify the intestinal absorption and metabolism of macronutrients provided either enterally or parenterally. Using these approaches, he is examining amino acid and oxidative substrate metabolism in the piglet intestine and is testing whether the trophic effects of GLP-2 treatment during total parenteral nutrition translate into enhanced gut function. Additionally, he is investigating the underlying mechanisms of enteral nutrition and GLP-2 action at the tissue and cellular level. These studies are aimed at determining how these nutritional and hormonal factors modulate the rates of intestinal blood flow and cellular protein turnover, proliferation and programmed cell death of mucosal epithelial cells. Dr. Burrin plans to identify how these factors affect the expression and activity of key signaling intermediates in these cellular pathways.
Nancy F. Butte, Ph.D.
Genetic and environmental causes of childhood obesity are the current focus of Dr. Butte’s research. A genomic scan for loci associated with the development of obesity is being performed in 1,600 Hispanic individuals from 300 nuclear families. Extensive phenotyping of the children includes measurements of body composition, food intake, eating behavior, energy partitioning during growth, energy expenditure, physical fitness and activity, and serum hormones and metabolites. Extensive research on the food intake, energy expenditure and body composition of infants and children preceded this work on childhood obesity. Other research is addressing the precursors of the metabolic syndrome in children, and the antecedents of nonalcoholic fatty liver disease in Hispanic children.
Joan Carter, R.D., M.B.A.
Ms. Carter's focus is the dissemination of information about the research activities of the USDA/ARS Children’s Nutrition Research Center through print and electronic materials describing the center's mission, organization, and research efforts. She is editor of the CNRC's award-winning consumer-oriented newsletter, Nutrition & Your Child, and webmaster for the center's web site, www.kidsnutrition.org, as well as for related faculty and research project web sites. She also serves as the center’s liaison to the public, the media, and Baylor College of Medicine communications personnel.
Ning-Hui Cheng, Ph.D.
Regulation of calcium transporters is essential for modulating Ca2+ signaling and/or Ca2+ homeostasis that are involved in the growth and adaptation of all organisms. Dr. Cheng’s research focus is to study the molecular mechanism underlying the regulation of plant ion transporters, such as particular calcium transporters (Calcium exchanger, CAX). He recently identified and isolated multiple regulatory proteins that can post-translationally modulate CAX-mediated Ca2+ transport and may play a vital role in integrating Ca2+ signaling with other cellular processes. He is also investigating the regulation of those ion transporter genes under normal and stress conditions. Using a genetic tool, he is performing a genome-wide screening for the genes that can transcriptionally regulate CAX expression. These studies will elucidate how the regulatory networks modulate Ca2+ signaling and homeostasis and also provide insights in developing new strategies to manipulate the nutritional quality of plant foods.
Brian S. Conklin, Ph.D.
Dr. Conklin is a bioengineer currently studying the effects of shear stress on the permeability of endothelium, specifically the permeability of endothelium in arteries to the passage of LDL. These studies involve the development of in vitro and ex vivo models that establish authentic arterial pulse waves with physiologically relevant wall shear stresses for the study of functional and gene expression effects on endothelial cells.
Orla M. Conneely, Ph.D.
Dr. Conneely’s research concerns the role of the iron-binding protein, lactoferrin (LF), in the regulation of homeostasis, growth and development of the gastrointestinal tract and in protection against bacterial infection and inflammation. Lactoferrin is a multifunctional protein found at very high levels in milk and in the body secretions that interface with the external environment. The second most abundant protein in human breast milk, LF is inactivated in infant formulae. Studies in LF-deficient mice generated by Dr. Conneely indicate that LF is not required for intestinal iron uptake, but plays a critical role in preventing excessive iron absorption during the neonatal period of development. She plans to continue her studies on the neonatal iron sequestration role of LF, and to examine its role in prevention against bacterial infections. She will also examine the consequences of LF ablation on intestinal inflammation, using mouse models of Crohn’s disease and ulcerative colitis.
Karen Weber Cullen, Dr. P.H.
Dr. Cullen’s research focuses on two main areas: promoting healthy school food environments, and enabling families to provide healthy food environments and appropriate parenting about food. Current projects include developing and implementing a school-based program for the prevention of Type 2 diabetes among youth, conducting a feasibility study on an Internet-based dietary behavior change program for families, and developing and implementing a family-based intervention in conjunction with the Texas Cooperative Extension program, and evaluating the impact of the new Texas School Food Policy.
Sonia A. Cunningham, Ph.D.
Dr. Cunningham is studying the contributions of adhesion molecules to the migration of leukocytes from blood into tissue, a potentially important step in the accumulation of macrophages in adipose tissue. These studies deal with the molecular interactions of adhesion molecules in a newly discovered family referred to as junctional adhesion molecules (JAMs). She has discovered two new members of this family and has developed mice that are selectively deficient in the expression of these two new JAM family members. These mice are currently being evaluated for phenotypic characteristics associated with the deletion of these genes.
Teresa A. Davis, Ph.D.
Dr. Davis' research goal is to identify the mechanisms by which hormones and nutrients interact to regulate the high rate of skeletal muscle protein deposition in the neonate. To achieve this objective, her research focuses on five main areas: the role of insulin, amino acids, and glucose in the regulation of protein synthesis in the neonate; the role of insulin, amino acids, and glucose in the regulation of the insulin and nutrient signaling pathways that lead to translation initiation in the neonate; the role of hormones, cytokines, and nutrients in the regulation of muscle protein synthesis during sepsis in the neonate; the role of development in the regulation of the protein synthetic response to dietary protein; and the role of nutrient intake and insulin in the anabolic response to growth hormone.
Debby Demory-Luce, Ph.D.
Two focal points of interest of Dr. Demory-Luce are the eating habits of preschool children and pediatric nutrition education for primary care providers. A current research area involves the examination of how preschool children’s eating habits are affected by environmental factors and their parents’ personal characteristics, such as weight and health-related beliefs.
Kenneth J. Ellis, Ph.D.
A primary goal of Dr. Ellis' research is to establish reference standards for body elemental composition in infancy, childhood and adolescence. This research focuses on the development and application of nuclear-based techniques for in vivo studies of human body composition. This approach provides knowledge of changes in growth and body composition that reflect the body's cumulative response to basic physiologic and metabolic processes. Detection of these changes often requires unique instrumentation like the CNRC's whole body counter, which monitors 40K, a naturally occurring isotope in humans. Dr. Ellis has continued to develop in vivo neutron activation techniques for clinical research and postmortem examinations, and he has extended the use of dual-energy X-ray absorptiometry to the examination of infants and children.
Marta L. Fiorotto, Ph.D.
The focus of Dr. Fiorotto’s research is the regulation of muscle growth rate during early postnatal life and its impact on muscle function in adulthood. The major objective is to identify how the developmental stage of muscle tissue influences both the short- and the long-term response of the muscle to two of the primary regulators of muscle growth: nutrient availability and endocrine factors (GHRH, growth hormone, and insulin-like growth factors). In addition to overall growth and body composition effects, Dr. Fiorotto is also examining the rate of muscle protein turnover, the expression of muscle-specific protein genes and transcription factors, satellite cell replication and accretion. For these studies, she uses animal models, such as transgenic mice with altered muscle growth and growth factor expression, as well as gene-transfer techniques in which an exogenous gene for GHRH is administered postnatally, or prenatally to the mother.
Jennifer Orlet Fisher, Ph.D.
Dr. Fisher’s research investigates the development of food preferences and the controls of food intake during infancy and early childhood. The broad goal of her research program is to understand how early eating environments modify young children’s eating behavior and health outcomes. Of particular interest is parents’ role in selecting foods of the family diet, in serving as models of eating behavior, and in making child feeding decisions. Currently, studies are being conducted to understand whether the regulation of energy intake and growth during the first two years of life are affected by maternal responsiveness in infant feeding. Another line of research evaluates the role of maternal feeding practices and family eating styles in overweight among Hispanic children. A series of experimental studies is testing the effects of portion size and serving practices on intake in young children.
John P. Foreyt, Ph.D.
The Family Lifestyle Overweight (FLOW) Prevention Program is designed to determine the effectiveness of a self-help intervention versus a community-based, instructor-led, multi-component physical activity and nutrition intervention for 10-15 year-old children and adolescents who are at risk for obesity. Both interventions involve a behavioral approach to weight management and both stress the importance of balancing exercise and healthy nutrition in a family-based environment. The interventions consist of 12 weeks of intensive training followed by 9 months of maintenance sessions and measurement visits. Each child and adolescent completes a baseline physical (i.e., height, weight, triceps skinfold, pulse, blood pressure, and fasting lipid profile) and psychosocial (i.e., eating disorder, quality of life) measures and returns for these measurements at 6-and 12-month follow-up visits.
Ian J. Griffin, M. B., Ch. B.
Dr. Griffin’s work focuses on understanding the mechanisms by which humans regulate zinc metabolism, particularly the metabolic adaptations to low zinc intakes, and the importance of marginal zinc status in human disease. His research uses stable nonradioactive isotopes and mathematical modeling techniques to describe zinc metabolism in health and disease.
Xinfu Guan, Ph.D.
Dr. Guan’s research goal is to understand the cellular mechanisms by which nutrients and hormones interact to control the gut development, growth, and function in the neonate. One focus is to define the physiological role and novel signaling networks by which glucagon-like peptide-2 (GLP-2, a nutrient-responsive neuropeptide) mediates epithelial cell proliferation and apoptosis, mucosal blood flow, nutrient uptake and metabolism in the gut. In collaboration with Dr. Burrin, Dr. Guan has shown that GLP-2 induces intestinal blood flow via a nitric oxide-dependent neurogenic mechanism, and the protein expression of GLP-2 receptor is colocalized with vasoactive neurotransmitters in endocrine cells and neurons in the human and porcine small intestine. Using multiple molecular approaches, his current research is to (1) determine if GLP-2 physiologically stimulates intestinal blood flow, nutrient uptake and metabolism, and cell survival in response to enteral feeding; (2) establish if GLP-2 is the key physiological mediator for intestinal adaptation in short-bowel syndrome mice; and (3) establish if local nitric oxide is the key down-stream mediator in GLP-2-mediated enteric signaling network in the neonate. Insights from such studies will provide critical mechanistic information that may lead to development of GLP-2 as a therapeutic strategy to treat intestinal dysfunctions (e.g., necrotizing enterocolitis and short-bowel syndrome). Another focus is to assess macronutrient metabolism and utilization from the whole body to specific organs. Dr. Guan has applied and developed a stable isotope tracer technique coupled with arteriovenous organ balance and real-time blood flow measurement to quantify the intestinal uptake and metabolism of glucose and amino acids provided parenterally for neonatal pigs.
Michael A. Grusak, Ph.D.
Dr. Grusak’s laboratory is involved in both plant physiology and human nutrition research. His plant physiology research is focused on the mechanisms and regulation of nutrient transport in plants. His long-term goals are to characterize the dynamics of nutrient flow within plants in order to determine the biophysical/molecular signals that regulate source-to-sink nutrient partitioning, and ultimately to use this information to enhance the nutritional quality of plant foods for human consumption. With regard to his human nutrition research, his laboratory group has developed hydroponic growth facilities and various protocols to intrinsically label plant foods with stable isotopes of important nutrients; these are then used to assess nutrient bioavailability and metabolism in humans.
Darryl L. Hadsell, Ph.D.
Insulin-like growth factors (IGFs) are necessary for mammary gland development and lactation. Despite this, the mechanisms by which these peptides regulate mammary gland function are poorly understood. The focus of Dr. Hadsell’s research is to understand the specific signaling mechanisms through which the IGF-I receptor (IGF-IR) regulates mammary gland development and lactation. Transgenic and/or gene targeting strategies are used to modify the activity of key IGF-IR signaling pathway intermediates within the mammary gland. These strategies have demonstrated: 1) that IGF-IR regulates early mammary ductal development through the ability to regulate cell cycle progression within specialized structures called terminal endbuds; 2) that IGF-I also acts during lactation to maintain mammary cell survival; and 3) that specific intracellular scaffolding proteins, termed insulin receptor substrates (IRS), are important to both the cell survival actions and to other potential actions of IGF-I on the regulation of milk volume and composition during early lactation.
Peter M. Haney, M.D., Ph.D.
Dr. Haney’s research goal is to understand the molecular cell biology of lactation. Current work focuses on glucose transport in the lactating mammary gland. Dr. Haney is studying the regulation of GLUT1, the only glucose transporter isoform identified in the mammary gland and in established and primary mammary epithelial cell lines in humans and rodents. He has shown that GLUT1, normally a plasma membrane protein, is diverted to the intracellular site of lactose synthesis in lactating mammary epithelial cells, suggesting that these cells have a unique and nutritionally important mechanism to alter GLUT1 targeting. Efforts are under way to elucidate this mechanism by identifying structural determinants of intracellular GLUT1 targeting in mammary epithelial cells. Video confocal microscopy demonstrates that intracellular GLUT1 targeting is highly dynamic and can be altered with certain drugs. Dr. Haney is also examining how GLUT1 gene expression and subcellular targeting regulate the synthesis of lactose.
Morey W. Haymond, M.D.
Dr. Haymond’s focus is to delineate and ultimately manipulate hormone and substrate factors regulating absorption, assimilation, mobilization and disposal of carbohydrates in infants and children. The delicate balance of nutrient availability to meet the energy and growth needs of children is frequently disturbed by chronic disease, infection, trauma and/or organ failure. The increase in type 1 and type 2-diabetes provides unique opportunities to study the effects of insulin, insulin resistance and obesity on macronutrient assimilation in children. Specific studies utilize stable isotopic tracer techniques to estimate insulin sensitivity, absorption of carbohydrates, proteolysis, protein synthesis, gluconeogenesis, carbohydrate disposal, and protein and fat metabolism. Current studies explore the impact of diet composition (fat and carbohydrate) on glucose homeostasis and macronutrient accretion in normal and obese children, the substrate, the hormonal and molecular regulation of lactation.
William C. Heird, M.D.
Dr. Heird’s research interests focus on the nutrient needs of low-birth-weight and other infants and children with special needs, including the specific amino acid needs of those who depend upon parenterally delivered nutrients, as well as ways of meeting these needs. An additional interest concerns the metabolism of essential fatty acids during infancy and childhood and the role of long-chain polyunsaturated fatty acids in infant development.
Karen Hirschi, Ph.D.
Dr. Karen Hirschi’s goal is to understand, at the cellular and molecular level, the events leading to blood vessel formation. She is interested in elucidating regulators of vascular cell recruitment, proliferation and differentiation needed for blood vessel assembly and maintenance. One aim is to define mechanisms by which soluble effectors, such as retinoids and TGF-beta, and cell-cell junctional components such as gap junctions, modulate vascular cell phenotype and cell cycle progression. Another focus is to investigate the potential of adult stem cells to contribute to neovascularization in response to tissue injury and growth. The mechanisms by which adult stem cells are recruited, induced to differentiate into vascular cells, and are functionally integrated into existing vascular networks, are of particular interest. Insights gained from such studies are applied to the optimization of clinically relevant treatments, including autologous vascular cell and gene therapy, assembly of blood vessel grafts, and vascularization of engineered tissues.
Kendal D. Hirschi, Ph.D.
Plants cannot run from environmental stresses; they must adapt. Dr. Kendal Hirschi is studying the mechanisms by which plants sequester nutrients and toxic metals into the plant vacuole to cope with environmental challenges. At the molecular level, his goal is to understand the structure, biological function, and regulation of transporter proteins that control trafficking into and out of the plant vacuole. Another major goal is to learn how to manipulate the expression and function of these transporters to increase the nutritional content of crop plants, improve plant productivity, and cleanse polluted soils. He views these objectives as integral components of the Green Revolution, the global agricultural movement whose aim is to end world hunger by developing innovative ways of increasing grain yields, particularly via the use of genetically improved food plant varieties.
Judy A. Hopkinson, Ph.D.
Dr. Hopkinson’s research goal is to define physiological and behavioral factors associated with optimal breastfeeding practices and the long term impact of breastfeeding on child health. To achieve this goal, her research focuses on the following areas: the impact of lactation on maternal and infant physiology; the identification of cultural factors and health care policies that influence breastfeeding duration and/or exclusivity; the characterization and etiology of breast and nipple discomfort encountered by breastfeeding women; and the relationship between health outcome and infant feeding practices.
Sheryl O. Hughes, Ph.D.
Dr. Hughes’ research focuses on patterns of parental socialization and how these behaviors affect children’s and adolescent’s health and development; specifically, how parenting behaviors influence dietary intake of young children and how these parental behaviors influence adverse eating styles in childhood. Current areas of research include the development of observational and parent-report techniques to assess feeding patterns as well as innovative methods of assessing food preferences and dietary intake among low-income minority parents and preschoolers in Head Start; and the development of a valid theory driven measure reflecting aspects of emotional security in child eating based on attachment theory in an ethnically diverse sample of low-income Hispanic and African-American parents of preschool children.
Russell P. Jago, Ph.D.
Dr Jago’s research focuses on the prevention of obesity and associated chronic diseases among children and adolescents through the promotion of physical activity. Of particular interest are understanding the environmental and personal factors that influence the physical activity levels of children and adolescents and designing and evaluating programs that are designed to increase the physical activity levels of these groups. Current projects include examining whether the environment affects the physical activity levels of adolescent boys, examining the relationship between the physical activity levels and chronic diseases risks of young children and developing a school-based program for the prevention of type 2 diabetes among middle school students.
Farook Jahoor, Ph.D.
Dr. Jahoor's research focuses on the metabolic alterations of specific nutrient transport and acute-phase proteins, amino acids, carbohydrate and lipids in response to different pathologies, including undernutrition, obesity (in pregnancy), diabetes mellitus, sickle cell disease and chronic infections, such as HIV. He also studies the roles of nitric oxide synthesis, inflammatory mediators and oxidative stress in pregnancy induced hypertension.
Craig L. Jensen, M.D.
Dr. Jensen's research is directed toward determining the optimal intakes of polyunsaturated fatty acids for term and preterm infants. The ability of infants to synthesize longer-chain n-3 and n-6 polyunsaturated fatty acids from their precursors, alpha-linolenic and linoleic acids, respectively, is being investigated using stable isotope techniques. The effects of different dietary intakes of essential fatty acids on biochemical and functional outcomes in both term and preterm infants are being assessed.
Craig A. Johnston, Ph.D.
Dr. Johnston is interested in developing and evaluating interventions to treat and/or prevent overweight in children and adolescents. More specifically, the interventions being studied provide a family-based behavioral approach with a focus on increasing physical activity, decreasing sedentary behaviors, increasing intake of fruit and vegetables, and decreasing intake of calorically dense foods.
Heidi E. Karpen, M.D.
Dr. Karpen’s research involves the study of Patched, a tumor suppressor gene responsible for Gorlin Syndrome. Patched is a member of the Sonic Hedgehog signaling pathway, critical for early embryonic patterning and development. Dr. Karpen is using mutations identified in Gorlin patients and sporadic basal cell carcinomas to define functional domains important for protein trafficking and function. The goal of this research is to better understand mechanisms of aberrant embryonic development and cancer formation so that targets for intervention may be identified.
Gerard Karsenty, M.D., Ph.D.
Dr. Karsenty’s research focus is on the regulation of bone remodeling by hormones that also affect body weight and reproduction. To that end, Dr. Karsenty is using mutant mouse strains in which either specific hormones or their receptors are deleted. He currently is studying how leptin controls bone mass. He hopes to determine whether leptin acts through a different set of secondary messengers to regulate body weight and bone mass, using mouse models generated in the laboratory. He also is exploring the concept that antagonizing the leptin pathway may be a way to treat osteoporosis without affecting body weight. Lastly, he is studying other hormones that may regulate body weight and bone mass.
Alexandre A. Lapillonne, M.D., Ph.D.
Dr. Lapillonne’s research interest is to determine whether, and how, early nutritional events affect long-term growth, metabolic function and development. His work has focused on the effect of intrauterine growth on body composition and postnatal growth, the effects of specific nutrients on gene transcription, and how alterations in gene transcription affect growth and body composition. Current research focuses specifically on the effect of n-3 polyunsaturated fatty acids on weight gain, body composition, fat oxidation, energy expenditure and transcription of genes controlling lipid oxidation and thermogenesis. He is also planning to assess how and when in early life, optimization of protein intake can maximize catch-up growth and neurological development of very-low-birth-weight infants. The overall goal of Dr. Lapillonne’s research is to optimize the nutritional management of extremely low-birth-weight infants in order to overcome long- lasting effects on growth and development.
Lihua Lai, M.D.
The primary interest of Dr. Lai’s studies is to understand, at the cellular and molecular level, the mechanisms of blood vessel formation. Dr. Lai is interested in elucidating regulators of vascular cell (endothelial and smooth muscle) recruitment, and proliferation and differentiation needed for blood vessel assembly and maintenance. The specific aim is to define the function and mechanisms of retinoic acid, Ephrin B2, SRF, Tbx6, and Qukking in vasculogenesis. The mouse model system is used to study the regulation of blood vessel assembly in vivo (transgenesis), in situ (embryo culture) and in vitro (coculture systems to study interactions between vascular cells and their precursors). Another focus of Dr. Lai’s research is investigating the potential of adult stem cells to contribute to neovascularization in response to tissue injury and growth.
Carlos H. Lifschitz, M.D.
Dr. Lifschitz's research relates to nutrient gut interaction and intestinal adaptation. The current project consists of the investigation of the effect of glutamine supplementation in neonatal infection of low birthweight infants.
Ronald L. McNeel, Dr. P.H.
Dr. McNeel’s research interests include evaluation of the role of dietary supplements and macronutrients in disease prevention and in reduction of risk factors associated with disease. Specific interests include the effects of macronutrients and dietary supplements (including herbals) on whole body lipid metabolism and energy homeostasis with emphasis on lipid metabolism of the adipocyte. The goal is to obtain a more complete understanding of the molecular mechanisms of action of macronutrients and dietary supplements as they relate to fat mass accretion. Special emphasis is given to the role of the peroxisome proliferator-activated receptor family, including PPAR alpha, PPAR beta, and PPAR gamma as well as their target genes in response to nutrient signaling. This understanding is critical for the development of new health promotion strategies and therapeutic approaches (nutritional, alternative herbal, and pharmacological) to the management and prevention of nutritional obesity.
Harry J. Mersmann, Ph.D.
Adipocyte growth and differentiation are regulated by various hormones and growth factors and may be altered by dietary components. Dr. Mersmann’s laboratory has studied the influence of the stage of development and of dietary factors on adipocyte beta-adrenergic receptors. Currently, the focus of his efforts is on adipocyte development. Porcine adipocyte precursor cells may be isolated from adipose tissue and when grown in culture in vitro under the proper conditions, differentiate to adipocytes. He has used this system to evaluate factors regulating the differentiation process and the influence of dietary components of differentiation. In addition to mRNA for the beta-adrenergic receptors, mRNA for various transcription factors that regulate differentiation (e.g., C/EBP-alpha or PPAR-gamma) and mRNA for key proteins that characterize the adipocyte (e.g., lipoprotein lipase and aP2) are being measured. He is particularly interested in the role of individual fatty acids in the stimulation or inhibition of adipocyte differentiation.
David D. Moore, Ph.D.
The receptors for retinoic acid, thyroid hormone, steroids, and other potent biological regulators belong to a nuclear hormone receptor superfamily. This family also includes a number of additional proteins called orphan receptors, which do not have known ligands. The conventional receptors regulate a variety of processes in developing and adult animals. The orphans are less well characterized, but it is thought that they also play important roles in diverse areas. The broad-ranging effects of these proteins are a consequence of their function as ligand-dependent, or in some cases, ligand-independent transcription factors. The main goal of Dr. Moore’s laboratory is to understand the mechanisms of action of the members of this superfamily. Toward this aim, he has identified a number of proteins that interact with both conventional and orphan receptors, and he is characterizing their functions.
Kathleen J. Motil, M.D., Ph.D.
The primary goal of Dr. Motil’s research is to understand the role of dietary and hormonal factors in the regulation of growth and body composition in girls and women with Rett syndrome, a neurodevelopmental disorder caused by a mutation in the MECP2 gene. This endeavor is relevant because the nutrient requirements for optimal health and functional performance are unknown in individuals with this rare genetic disorder. She currently is studying the natural history of osteopenia in girls and women with Rett syndrome using balance methods, stable isotope techniques, and dual-energy x-ray absorptiometry to characterize the adaptive responses of body mineral metabolism to dietary, hormonal, or pharmacologic perturbations. Future research will employ isotopically labeled calcium and dual-energy x-ray absorptiometry to examine the bone mineral response to dietary and pharmacologic interventions. The ultimate aim of these studies is to elucidate the mechanisms that contribute to bone mineral loss and to provide recommendations for dietary calcium intakes in girls with this neurological disability.
Paul A. Nakata, Ph.D.
Calcium in plants is sequestered as a complex with other substances such as oxalates, phytates, fiber, fatty acids, proteins and other anions. Some of these substances (oxalates and phytates) are considered antinutrients, and render the calcium in plant foods unavailable for nutritional absorption by humans. The purpose of Dr. Nakata's research program is to elucidate the mechanism regulating calcium partitioning and sequestration in plants. The acquired information will be applied toward the rational design of strategies to enhance calcium abundance and bioavailability in plant food products.
Buford L. Nichols, M.D.
Dr. Nichols’ research project focuses on the interactions of nutrients and genes, especially the regulation of genes as they contribute to the development of diet associated with degenerative diseases, such as diabetes and atherosclerosis. Our research objective is to determine the mechanisms by which dietary starch interacts with the gene expressing maltase-glucoamylase (MGAM). Maltase-glucoamylase is the gate-keeping enzyme that determines small intestinal starch digestion into glucose. The function and regulation of maltase-glucoamylase is under investigation in knockout mice and children with deficient starch digestion. Epidemiological reports indicate that about 15-30% of US children suffer from chronic abdominal pain. Twenty-six percent of children with chronic abdominal pain have deficiencies of maltase-glucoamylase enzyme activity and poor small intestinal starch digestion.
Theresa A. Nicklas, Dr. P.H.
Dr. Nicklas’ research focuses on nutritional epidemiology and intervention aspects of chronic disease prevention and health promotion; specifically, how eating behaviors and other lifestyles influence the development of chronic disease risk factors early in life and the behavioral factors influencing the development of adverse lifestyles in childhood. Current areas of research include a detailed investigation of the relationship among eating patterns, diet quality, and obesity in children and young adults; an examination of environmental influences on fruit, juice, and vegetable consumption and body mass index of Head Start preschool children; development of a valid and reliable computerized food preference measure for use with preschool children; and examination of predictors of children’s serving sizes and mealtime intake. Planned studies include a behavior-based intervention aimed at favorably influencing food preferences and consumption by African- and Hispanic-American preschool children attending Head Start and a behavioral-based family intervention designed to increase fruit, fruit juice, and vegetable consumption by preschool children.
Sharon I. O’Donnell, Ph.D.
Dr. O'Donnell's research interests focus on the role of the market on food and physical activity choices. Spatial disparities in the local market's availability of nutritious foods can result in higher total food costs for some households. Using data that describes the full Houston market, her research has found that the locations of grocery stores are not the outcome of a competitive market and there is an association between the concentration of specific ethnic groups and spatial concentration of higher quality food stores. Planned studies include economic analysis to determine if there exists spatial disparities in physical activity resources for children and a study to determine if low income, economically "at risk" households (households in markets with higher than average housing and transportation costs) increase their nutrient intake by participating in the Food Stamps Program.
Heather A. Patrick, Ph.D.
Dr. Patrick’s program of research focuses on the role of both nutrition and exercise in obesity prevention, using social psychological and developmental theories to address the mechanisms through which long-term behavior change and adherence can be achieved (e.g., healthy eating, regular exercise, weight loss/management). Her specific interests lie in the role of interpersonal relationships in promoting (or inhibiting) health behaviors. For example, Dr. Patrick’s work dealing with fruit and vegetable choices involves examining the role of caregiver feeding styles in children’s eating behaviors. She is also beginning to study how parent-child relationships during the teenage years influence a broad spectrum of health behaviors as children transition from adolescence into young adulthood. This research focuses specifically on the “freshman 15” weight gain phenomenon and understanding why this occurs with some students and not others. She is also examining whether differences in parent-child relationships distinguish those students who engage in what might be termed “healthy exploring” (e.g., begin making their own food choices, learn about their daily energy requirements, and perhaps gain some weight initially, but then go back to a healthy weight) when they go to college from those who “go off the deep end” (e.g., develop very little self-regulation and consistently choose foods that are high in fat but of otherwise very little nutritive value).
Monique Rijnkels, Ph.D.
Dr. Rijnkels’ primary research goal is to understand the regulation of the casein genes, encoding major nutritional proteins in milk, and the genomic domain in which these genes reside. The Genomics approach used to study the transcriptional regulation of the casein gene cluster region combines three lines of research: The study of the chromatin structure and remodeling in the casein gene cluster region related to tissue type and development, using e.g. Chromatin Immuno-Precipitation (ChIP) assays; computational approaches to identify evolutionary conserved regions with potential regulatory function and the transacting factors that might bind them; and functional analysis of potential regulatory regions in transgenic mice. In addition, the non-casein genes in this genomic domain are studied as they potentially share functional properties and spatial expression patterns (expressed in mammary glands) as well as evolutionary ancestry.
Jeffrey M. Rosen, Ph.D.
Dr. Rosen’s research objectives are to elucidate the mechanisms regulating the normal development of the mammary gland and to determine how these regulatory mechanisms deviate in breast cancer. Studies of the role of systemic hormones and local growth factors on critical periods of development in the mouse mammary gland are under way. Transgenic and knockout mouse models are being used to examine the roles of specific transcription factors and their dominant-negative isoforms, postnatal mammary gland development, and the changes in normal signal transduction pathways that are involved in the progression from the normal mammary gland to preneoplasias, as well as the role of mutant p53 in genomic instability and the development of aneuploidy. In addition, methods that permit the analysis of both gain and loss of specific gene function selectively in the mammary gland have been developed.
Robert J. Schwartz, Ph.D.
Dr. Schwartz conducts research focused on defining the molecular basis underlying the establishment and maintenance of skeletal, cardiac and smooth muscle differentiation. Of special interest is Nkx2-5, a transcription factor instrumental in the patterning of the embryonic heart. The heart appears to develop as a modular organ, such that a distinct transcriptional regulatory program controls each anatomical region. Consistent with this notion, the heart tube can be divided into segments that form the atria, left ventricle, right ventricle, and ventricular outflow tract. Precursors of these regions appear to originate from separate lineages, which develop according to their positions along the anteroposterior axis of the embryo. Recent studies have revealed cis-regulatory elements that direct cardiac transcription specifically in the left or right ventricular chambers and atria, which could be important for the physiologic and functional differences of the chambers of the adult heart.
Partha Sen, Ph.D.
Dr. Partha Sen is the director of the Child Health Research Center (CHRC) Molecular Core Laboratory. The laboratory provides DNA sequencing and DNA synthesis services to the CHRC awardees and their mentors and Baylor faculty at large. Dr. Sen is also involved in research related to alveolar capillary dysplasia (ACD). This is a genetic disorder that causes misalignment of lung blood vessels, and is also characterized by a severe reduction of capillaries in the lungs of the patient. The relentless course of the disease culminates in the death of the neonate despite intensive therapy. The inheritance of the disease is presumed to be autosomal recessive. The primary goal of the research project is to identify the causative gene for this human disorder.
Robert J. Shulman, M.D.
Dr. Shulman is investigating the factors regulating gastrointestinal function. His studies include examination of the roles of diet and feeding regimen on the developing gastrointestinal tract of the preterm infant. In addition, Dr. Shulman is researching the factors contributing to the expression of recurrent abdominal pain in older children including the role of diet and alterations in intestinal bacterial flora.
Roman J. Shypailo, B.S.
The unprecedented growth of technology during the past decade has created challenges for researchers. Powerful computers and data acquisition equipment enable rapid accumulation of information that requires processing. The CNRC Body Composition Laboratory houses sophisticated instruments designed to measure the elemental composition of the human body using nuclear-based techniques. Each instrument is in a dynamic state of evolution. New measurement systems are being developed, including a multiparameter whole-body counter capable of isolating and measuring a signal coming from a specific site in the body, and a portable 40K counter for use in a hospital setting. Coordinating these efforts and incorporating new technology are the primary focus of Mr. Shypailo's work.
C. Wayne Smith, M.D.
Dr. Smith’s research deals with the effects of dietary fat on the inflammatory processes in adipose tissue, liver and blood. There are two main goals of this work. The first is to determine the role played by macrophages in adipose tissue. Studies are underway to determine the kinetics of macrophage accumulation in different fat pads in animals on diets differing in lipid composition, the origins of these macrophages and the consequences of blocking their accumulation. These studies address the hypothesis that macrophage/adipocyte interactions play a role in the proinflammatory responses seen in obesity. The second major goal is to determine the role of the hepatic response to dietary lipids in the systemic inflammatory response seen in obesity. A component of these studies deals with the development of steatohepatitis and a potential contribution of portal endotoxemia. Animal models in rats and mice have been developed for these studies.
E. O’Brian Smith, Ph.D.
Dr. E. O’Brian Smith provides statistical design, analysis, and teaching support to the USDA/ARS Children’s Nutrition Research Center, the General Clinical Research Center, the Pediatrics Department, and Baylor College of Medicine investigators. This support includes teaching statistical methods, developing grant applications, the design of research protocols, statistical analysis, interpretation, and manuscript preparation. His support services range from basic consultation to extensive involvement in a project.
Barbara Stoll, Ph.D.
Dr. Stoll’s research focuses on how enteral nutrients mediate the effects that lead to normal growth and function of the small intestine. Using the neonatal pig as a model for the gastrointestinal tract of the human infant, one major goal is to elucidate the critical cellular and hormonal signals that mediate the stimulatory effects of enteral nutrition, including the role of the intestinal trophic actions of the gut-specific peptide GLP-2. Isotopic tracers, coupled with arterio-venous organ balance and blood flow measurements are used to quantify the intestinal absorption and metabolism of macronutrients in neonatal pigs maintained by enteral or total parenteral nutrition (TPN), the latter of which is a condition where gut growth is greatly compromised. Dr. Stoll is also investigating the underlying trophic mechanisms of enteral nutrition and GLP-2 action at the tissue and cellular level in terms of cellular protein turnover, proliferation, and programmed cell death of mucosal epithelial cells.
Janice E. Stuff, Ph.D.
Dr. Stuff's interest is nutritional epidemiology and the role of nutrition in chronic diseases and public health problems. One emphasis is to understand dietary carcinogen and chemopreventive exposure, the genetic susceptibility to dietary carcinogens, and their interaction as determinants for cancer. Dr. Stuff is developing and validating databases of N-nitroso compounds and isothiocyanate compounds in foods in order to investigate their role in the development and prevention of cancer. Another interest is to investigate the role of diet, body composition, and hormone levels in the development of risk factors for breast cancer. Dr. Stuff also collaborates with the USDA/ARS Delta NIRI (Nutrition Intervention Research Initiative), an initiative designed to measure the nutrition and health status of individuals and communities in the Lower Mississippi Delta region, and to develop interventions. This project also investigates the impact of food insecurity on the health, nutritional requirements and nutritional status of children.
Agneta L. Sunehag, M.D., Ph.D.
The focus of Dr. Sunehag’s research is carbohydrate metabolism in infants and children. In particular, she is interested in the metabolism of very premature infants during their first days of life. The aim of her studies is to determine how these infants utilize their gluconeogenic pathway to produce glucose from parenterally administered lipid and amino acid solutions. The ultimate goal of these studies is to optimize the composition of neonatal parenteral nutrition solutions to prevent both hypo- and hyperglycemia, while providing a sufficient energy intake for normal growth. She is also investigating which factors regulate glucose metabolism, particularly gluconeogenesis, in sick newborns (represented by Extremely low-birth- weight infants, infants with Respiratory Distress Syndrome and infants with Congenital Heart Disease). Her other major research interest is to determine the effects of dietary macronutrient intake, obesity, exercise and ethnicity on parameters of glucose metabolism, particularly insulin sensitivity in children and adolescents. Dr Sunehag is also involved in studies of glucose metabolism in lactating women and in children with diabetes.
Agus Suryawan, Ph.D.
Early postnatal period is characterized by rapid growth, particularly in skeletal muscle. Dr. Suryawan’s previous observations indicate that higher rate of skeletal muscle protein synthesis in neonates is partly due to increased activation of insulin signaling components leading to translation initiation. Despite tremendous efforts, the factors that regulate high rate of skeletal muscle protein synthesis are not completely understood. My research focuses on understanding the role of TGFbeta family and their binding proteins in the regulation of skeletal muscle growth in neonates. Recent studies have focused on the effect of follistatin (an activin binding protein) on the regulation of skeletal muscle growth by determining its effects on protein synthesis and the activation of insulin signaling proteins and translation initiation factors.
Marilyn A. Swanson, PhD
Dr. Swanson serves as the USDA-CSREES National Program Leader for Maternal and Child Health stationed at the USDA/ARS Children's Nutrition Research Center (CNRC). This unique partnership provides the formal mechanism to connect maternal and child health research with the educational opportunities available through the USDA Cooperative Extension System. Dr. Swanson complements the CNRC research and transfer mission; assists in providing a mechanism for rapidly translating updated nutrition research findings; helps in making the "translations" available to a wide range of governmental and non-governmental agencies, as well as providers and recipients of maternal, infant and child nutrition and health care; identifies areas of educational needs of maternal, infant, and child health components within the Extension network; and helps identify educational research needs that may form the basis for new cooperative research.
Deborah I. Thompson, Ph.D.
Dr. Thompson is interested in children’s problem solving to overcome barriers to physical activity and in the design, development, and evaluation of interactive multi media programs promoting healthy nutrition and physical activity behaviors to youth. Dr. Thompson is studying the use of Dual Code Theory and how to best design interactive multi media programs to promote health behavior change, as well as the impact of monetary incentives on log-on rates to electronic media promoting diet and physical activity change. She helped design an interactive multi media program promoting healthy nutrition behaviors to parents of minority youth and is a member of the team developing an interactive multi media game promoting healthy diet and physical activity behaviors to youth. Dr. Thompson also coordinates qualitative research for a large, multi-site study to prevent type 2 diabetes among middle school youth and provides mentorship for the qualitative data coordinator for a Small Business Industrial Grant to develop an interactive multi media game promoting healthy nutrition and physical activity behaviors to middle school youth.
Qiang Tong, Ph.D.
The study of adipose tissue development may reveal clues about the molecular mechanisms of metabolic diseases, such as type 2 diabetes and cardiovascular disease. Dr. Tong has established the mammalian GATA transcription factors as molecular gatekeepers in the early stages of adipogenesis. He demonstrated that both GATA-2 and GATA-3 transcription factors are negative regulators of adipocyte differentiation. This effect is mediated through direct suppression of the promoters of adipogenic factors PPARg and C/EBPa by GATA factors and protein-protein interactions between GATA and C/EBPa or C/EBPb. Currently he is investigating the regulation of GATA factors at the protein level, with the goal of characterizing the identity and dynamics of the GATA protein complexes during adipogenesis, and the role of GATA in the lineage determination of adipogenic progenitor cells. He also plans to identify new regulators of adipogenesis and to develop mouse models to study the roles of these genes in obesity.
Chermaine L. Tyler, Ph.D.
Dr. Tyler is interested in studying the effectiveness of community-based, instructor-led, multi-component physical activity and nutrition intervention for 10-15 year-old children and adolescents who are at risk for obesity. Both interventions involve a behavioral approach to weight management and both stress the importance of balancing exercise and healthy nutrition in a family-based environment.
Ignatia B. Van den Veyver, M.D.
The neurodevelopmental disorder Rett syndrome is caused by mutations in a gene on the X chromosome, MECP2. This gene encodes methyl-CpG-binding protein 2, thought to be a transcriptional repressor that binds to methylated CpGs in DNA. Based on this, Dr. Van den Veyver proposes the more general hypothesis that DNA methylation is important for regulation of gene expression during development, especially of the brain. There is evidence that DNA methylation can be influenced by methyl-donor enriched diets, containing substances such as folic acid and betaine. We are investigating in animal and cell culture models whether this treatment can alter DNA methylation and gene expression in the brain. This is not only important for conditions such as Rett syndrome, but may also provide a better understanding for the role of such agents in other prenatally-onset disorders and birth defects, such as neural tube defects or for the fetal origin of adult-onset disorders.
Robert A. Waterland, Ph.D.
Research in the Waterland laboratory aims to understand how nutrition during prenatal and early postnatal development affects individual susceptibility to various adult-onset chronic diseases. We have focused on nutritional influences on developmental epigenetics as a likely mediating mechanism. Epigenetic gene regulatory mechanisms regulate tissue-specific patterns of gene expression and are established during development. Cytosine methylation is an epigenetic mechanism of particular interest to us because mammalian one-carbon metabolism, which supplies the methyl groups for DNA methylation, is intimately dependent on dietary methyl donors and cofactors.
William W. Wong, Ph.D.
Dr. Wong’s main research interests include strategies to prevent childhood obesity and the use of dietary supplementation to prevent chronic diseases. Based on the data he collected in the Houston Independent School District to document the prevalence and risk factors of childhood obesity, a grant application designed to determine the appropriateness and effectiveness of a school-based physical activity program to prevent obesity among Hispanic children is going to be submitted to the National Institutes of Health. With respect to projects related to the use of dietary supplements to prevent chronic diseases, Dr. Wong is currently investigating the safety, efficacy, and optimal dosage of soy isoflavones to prevent osteoporosis in postmenopausal women and the effects of soy isoflavones on nitric oxide production and blood pressure in postmenopausal women with high-normal blood pressure.
Issa F. Zakeri, Ph.D.
Dr. Zakeri is interested in Nutrimetrics, the application of statistical methods to problems in nutrition. His goal is to advance, develop and apply more accurate and computationally flexible statistical techniques to analyze and better understand many complex problems in nutrition, particularly behavioral nutrition. His primary research interests in statistics are time series analysis, multivariate analysis, sequential analysis, and statistical pattern recognition.