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author:("grigsby, R")
1.  Infant colic and feeding difficulties 
Archives of Disease in Childhood  2004;89(10):908-912.
Aims: To examine the relation between colic and feeding difficulties and their impact on parental functioning for a primarily clinic referred sample.
Methods: Forty three infants (and their mothers) were enrolled between 6 and 8 weeks of age. Infants were divided into two groups, colic (n = 19) and comparison (n = 24), based on a modified Wessel rule of three criteria for colic. Families were assessed at two visits; one occurred in the laboratory and one occurred in a paediatric radiology office. Outcome measures included the clinical assessment of infant oral motor skills, behavioural observation of mother-infant feeding interactions, maternal questionnaires on infant crying, sleeping and feeding behaviours, and the occurrence of gastro-oesophageal reflux (GOR) in the infants using abdominal ultrasound.
Results: Infants in the colic group displayed more difficulties with feeding; including disorganised feeding behaviours, less rhythmic nutritive and non-nutritive sucking, more discomfort following feedings, and lower responsiveness during feeding interactions. Infants in the colic group also had more evidence of GOR based on the number of reflux episodes on abdominal ultrasound as well as maternal report of reflux. Mothers in the colic group reported higher levels of parenting stress.
Conclusions: Results provide the first systematic evidence of feeding problems in a subgroup of infants with colic. Data also illustrate the impact of these difficulties on parental and infant functioning. The association between feeding difficulties and colic suggests the potential for ongoing regulatory problems in infants presenting with clinically significant colic symptoms.
PMCID: PMC1719691  PMID: 15383432
2.  Environmentally relevant xenoestrogen tissue concentrations correlated to biological responses in mice. 
Environmental Health Perspectives  2000;108(10):973-977.
The effects of xenoestrogens have been extensively studied in rodents, generally under single, high-dose conditions. Using a continuous-release, low-dose system in ovariectomized mice, we correlated the estrogenic end points of uterine epithelial height (UEH) and vaginal epithelial thickness (VET) with concentrations of two organochlorine pesticide isomers in fat and blood. Silastic capsules containing a range of doses of either ss-hexachlorocyclohexane (ss-HCH) or o, p'-dichlorodiphenyltrichloroethane (o,p'-DDT) were implanted subcutaneously, and animals were killed after 1 week. Average blood levels achieved by the various doses were 4.2-620 ng/mL for o,p'-DDT and 5.0-300 ng/mL for ss-HCH. Fat concentrations of o,p'-DDT and ss-HCH correlated linearly to blood levels (o,p'-DDT, r(2) = 0.94; ss-HCH, r(2) = 0.83). Fat concentrations (nanograms per gram of tissue) were higher than blood concentrations (nanograms per milliliter) by 90 +/- 5- and 120 +/- 9-fold (mean +/- SE) for o, p'-DDT and ss-HCH, respectively. The VET ranged from 12 +/- 0.9 microm in controls to 114 +/- 8 microm in treated animals, and was correlated to blood levels of either treatment compound. The UEH ranged from an average of 7.7 +/- 0.3 microm in controls to 26 +/- 2 microm in high-dose o,p'-DDT-treated animals. The UEH was also correlated with ss-HCH concentration, but it plateaued at approximately 11 microm at the highest doses. The lowest blood concentrations that produced statistically significant increases in VET or UEH were 18 +/- 2 ng/mL o,p'-DDT and 42 +/- 4 ng/mL ss-HCH. These values are within the same order of magnitude of blood concentrations found in some human subjects from the general population, suggesting that human blood concentrations of these organochlorines may reach estrogenic levels.
PMCID: PMC1240131  PMID: 11049819
3.  Strain differences in vaginal responses to the xenoestrogen bisphenol A. 
Environmental Health Perspectives  2000;108(3):243-247.
Bisphenol A (BPA) is the monomer component of polycarbonate plastics and epoxy resins; human exposure derives from leachate in foodstuffs packaged in certain plastics or from epoxy-based dental appliances. BPA stimulates prolactin secretion in Fischer 344 (F344) rats but not in Sprague-Dawley (S-D) rats. The present studies were performed to determine if another classic estrogen target tissue, the rat vagina, responds to BPA in a strain-specific manner. In F344 rats BPA increased DNA synthesis in vaginal epithelium with a median effective dose (ED(50)) of 37.5 mg/kg body weight; DNA synthesis was not stimulated in S-D rats by any dose tested. Clearance of (3)H-BPA from blood followed the same time course in both strains of rats, with a half-life of 90 min. Scatchard analysis of [(3)H]estradiol binding showed no strain differences in concentration or affinity of the vaginal estrogen receptor. BPA increased the level of mRNA for the immediate early gene, c-fos, with similar dose-response curves in both rat strains. Thus, F344 and S-D rats exhibit differences in sensitivity to BPA at the level of cell proliferation in the vaginal epithelium. However, metabolic clearance of BPA and the early events that lead to the proliferative response, receptor-ligand interaction and induction of immediate early genes, show no strain differences. These observations suggest that differences in intermediate effects must account for the difference in sensitivity of the proliferative response to the xenoestrogen. Furthermore, these results point to the need for caution in choosing a suitable end point and animal model when seeking to test the estrogenic effects of xenobiotics.
PMCID: PMC1637966  PMID: 10706531
4.  Evaluating the effects of endocrine disruptors on endocrine function during development. 
Environmental Health Perspectives  1999;107(Suppl 4):613-618.
The major concerns with endocrine disruptors in the environment are based mostly on effects that have been observed on the developing embryo and fetus. The focus of the present manuscript is on disruption of three hormonal systems: estrogens, androgens, and thyroid hormones. These three hormonal systems have been well characterized with regard to their roles in normal development, and their actions during development are known to be perturbed by endocrine-disrupting chemicals. During development, organs are especially sensitive to low concentrations of the sex steroids and thyroid hormones. Changes induced by exposure to these hormones during development are often irreversible, in contrast with the reversible changes induced by transient hormone exposure in the adult. Although it is known that there are differences in embryonic/fetal/neonatal versus adult endocrine responses, minimal experimental information is available to aid in characterizing the risk of endocrine disruptors with regard to a number of issues. Issues discussed here include the hypothesis of greater sensitivity of embryos/fetuses to endocrine disruptors, irreversible consequences of exposure before maturation of homeostatic systems and during periods of genetic imprinting, and quantitative information related to the shape of the dose-response curve for specific developmental phenomena.
PMCID: PMC1567510  PMID: 10421771

Results 1-4 (4)