2001 Faculty Research Interests
Dr. Abrams' research projects are designed to use stable isotopes
to evaluate mineral metabolism in infants and children. True dietary
calcium absorption and bone formation and turnover are determined
using orally and intravenously administered stable isotopes of calcium.
Studies in children with mineral deficiencies are designed to determine
the etiology of the mineral deficiency and the possible response
to therapy. Studies are under way to evaluate the absorption of
calcium and iron from milk, formula and dietary supplements in children
age 4-12 months. Studies are being conducted to determine the iron
needs of children with rheumatoid arthritis.
Cheryl B. Anderson, Ph.D.
Dr. Andersons research is aimed at the promotion of regular
physical activity by understanding its determinants, including self-identity
as a motivational factor in health behavior, and the development
of psychometrically valid and reliable measurement instruments of
attitudes and behaviors. Her work focuses on the description and
measurement of athletic identity and its relation to physical activity
in adolescents, children, and parents, as well as the factors that
contribute to identity formation, stability, and change.
Tom Baranowski, Ph.D.
Eating larger amounts of fruit, 100% juice and vegetables has been
shown to provide protection from several chronic diseases, and may
enhance weight control. Eating practices are learned in childhood.
The focus of the research conducted by Janice and Tom Baranowski
is on theory-based programs aimed at determining how to help children
eat more fruit, 100% juice and vegetables. Their many community-based,
nutrition education research projects have included GIMME
5, a school-based class curriculum intervention; 5 A
Day Boy Scout Achievement Badge; Squires Quest!,
a school-based, interactive, multimedia, nutrition education game;
and Bringing It Home, a school-based program designed
toward influencing the parents of 4th-grade children. All the individuals
targeted by these programs showed some change in dietary behavior.
The researchers also demonstrated that an interactive, multimedia
program for dietary assessment among 4th-grade children worked almost
as well as a dietitian-conducted, 24-hour dietary recall. Janice
and Tom Baranowski currently are actively involved in the Houston-area
Fun, Food and Fitness Program, which is part of the
national Girls Health Enrichment Multi-site Study, aimed at
the prevention of obesity in 8-year-old African-American girls.
Dennis M. Bier, M.D.
Dr. Bier's primary research interest is the regulation of interorgan
transport of metabolic fuels; specifically, substrate and hormonal
regulation of glucose, lipid, and protein/amino acid fuels. This
work has taken two principal directions. The first entails the regulation
of endogenous fuel availability for metabolic functions when a subject
is ill and incapable of ingesting sufficient food. The second involves
the assessment of the metabolic fates of ingested, exogenous fuels
under various classical nutritional circumstances. In each instance,
he has developed and employed a wide variety of stable isotope tracer
kinetic methods to quantify substrate flux, metabolism, precursor-product
relationships, and irreversible oxidation to excreted end products.
The physiological information obtained also has been used to further
assess aberrations in interorgan fuel transport consequent to a
variety of pathological conditions.
Douglas G. Burrin, Ph.D.
Dr. Burrins major research objective is to elucidate the cellular
and hormonal signals that mediate the stimulatory effects of enteral
nutrition on the growth and function of the neonatal intestine.
Recent studies have established the quantity and quality of enteral
nutrients necessary for maintaining normal intestinal growth and
function. He has found that the neonatal intestine utilizes a substantial
proportion of the dietary nutrients to maintain normal growth. He
also has found that the secretion of the gut-derived peptide, glucagon-like
peptide 2 (GLP-2), is closely correlated with enteral nutrient intake,
and that infusion of GLP-2 produces intestinal trophic effects when
given to neonatal pigs. In contrast, treatment with dexamethasone
has a potent catabolic effect on the neonatal intestine. Future
studies will investigate the physiological significance of GLP-2,
and how it affects intestinal protein and amino acid metabolism
in neonatal pigs. He will examine whether the catabolic effects
of dexamethasone compromise intestinal absorptive function, and
how the provision of either minimal enteral nutrition or GLP-2 ameliorates
the actions of dexamethasone. To understand how these nutritional
and hormonal factors modulate intestinal growth, he will quantify
the rates of cellular protein turnover, proliferation and programmed
cell death. How these factors affect the expression and activity
of key intermediates in these cellular pathways will be identified.
Nancy F. Butte, Ph.D.
The energy requirements of reproductive women and their infants
are the focus of Dr. Butte's research. Her major interests are the
functional consequences of variations in energy balance on pregnancy
outcome, lactation performance, and infant growth and development.
To further these evaluations, methodologies have been developed
to measure energy expenditure and body composition in the populations
of interest, including room respiration calorimeters and the doubly
labeled water method for the measurement of free-living energy expenditure.
Factors that predispose women to postpartum weight retention and
later development of obesity are under investigation. Also, genetic
and environmental factors that predispose infants and children to
the development of obesity are being explored.
David M. Cohen,
Dr. Cohens research concerns the regulated coordination of
metabolic fluxes that is fundamental to health and sustained by
adequate nutrition. Study of the quantitative relationships among
metabolic flux rates depends on accurate measurement of those rates,
preferably in vivo. To this end, he has investigated mathematical
aspects of modeling rates of metabolic pathways, subsequent to the
administration of isotope-labeled precursors. An important focus
of Dr. Cohens work is the measurement of cerebral metabolism
in vivo, using nuclear magnetic resonance spectroscopy. Currently,
he is developing a new method for estimation of the rate of cerebral
glucose metabolism, with a substantial improvement in time resolution.
In the long term, he hopes to learn more about the role of diet
in support of brain metabolism and function.
Orla M. Conneely, Ph.D.
The objective of Dr. Conneelys research is to establish the
role of nuclear receptors in vertebrate development. Nuclear receptors
comprise a large family of structurally related transcription factors
regulating the expression of genes that control a variety of developmental
and physiological responses to diverse stimuli.
Austin J. Cooney, Ph.D.
Dr. Cooneys research goal is to understand the mechanism of
action of the transcription factor GCNF in regulating embryonic
gene expression, and the influence of the maternal diet on its activity.
To achieve this objective, his research focuses on identifying GCNF-
responsive target genes expressed during embryogenesis and studying
the GCNF mode of regulation of these genes. To date, he has been
able to identify Oct4 as a GCNF- responsive gene that is silenced
in somatic cells after gastrulation by GCNF. Using a yeast two-hybrid
screen, he has identified DNA methyl transferases as interacting
partners of GCNF. Methylation of DNA around genes has been implicated
in the silencing of genes, so this would be the first example of
regulated and targeted DNA methylation by specific recruitment of
a DNA methyltransferase. His laboratory is using knockout mouse
models and the multipotent embryonic carcinoma cell P19 to study
GCNFs regulation of Oct4 expression via DNA methylation
Karen Weber Cullen, Dr. P.H.
Dr. Cullens research focuses on the prevention of diet-related,
chronic diseases through the development, implementation, and evaluation
of nutrition behavior-change programs for children and adolescents.
Of particular interest are programs aimed at increasing childrens
fruit and vegetable consumption, using unique delivery channels.
Current projects include implementing and evaluating an environmental
behavior-change program involving middle-school cafeteria a la carte/snack
bars; developing and implementing a school-based program aimed at
the prevention of type 2 diabetes among youth; and conducting a
feasibility study of an Internet-based, dietary behavior-change
program aimed at families.
Teresa 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 four main areas: the role of insulin and
amino acids in the regulation of protein synthesis in the neonate;
the role of insulin and amino acids in the regulation of the insulin
signaling pathway which leads to translation initiation; the role
of hormones, cytokines, and nutrients in the regulation of muscle
protein synthesis during sepsis; and the role of insulin and nutrient
intake in the anabolic response to growth hormone.
Debby Demory-Luce, Ph.D.
Two focal points of interest of Dr. Debby 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 childrens eating habits are affected
by environmental factors and their parents personal characteristics,
such as weight and health-related beliefs.
Kenneth J. Ellis,
The 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 counters, which monitor
40K, a naturally occurring isotope in the human. Dr. Ellis has developed
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.
The effects of chronic alterations in nutrient intake on the growth
and development of skeletal muscle are the focus of Dr. Fiorotto's
research. Currently, she is attempting to show that the nature of
skeletal muscle response is dependent on the developmental stage
at which the organism is subjected to a nutritional insult. She
is also attempting to identify the underlying factors responsible
for the age?related change in the sensitivity of skeletal muscle
to nutritional perturbations. Dr. Fiorotto also will evaluate the
consequences of changes in sensitivity on the numerous functional
roles of skeletal muscle in the body.
Dr. Fishers goal is to understand behavioral and environmental
factors that modify food intake regulation and growth patterns during
early childhood. To this end, her research focuses on childrens
early eating experiences and learning about eating within the family.
In particular, Dr. Fishers work evaluates childrens
eating patterns as a function of parents choices regarding
the types of foods that constitute the family diet, parents
models of eating behavior, and parents child-feeding practices.
Her current projects investigate the extent to which eating in the
absence of hunger constitutes a behavioral phenotype of overweight
Hispanic children, the extent to which it is related to characteristics
of the family eating environment, and the extent to which this type
of eating behavior reflects a shared eating style among family members.
Ian J. Griffin,
M. B., Ch. B.
Dr. Griffins work is to understand 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 (e.g., Crohns disease.) His research uses
stable (i.e., nonradioactive) isotopes and mathematical modeling
techniques to describe zinc metabolism in health and disease.
Michael A. Grusak, Ph.D.
Dr. Grusaks 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.