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Biomedical subjects

Peter Hindmarsh

Publications and source records attributed to Peter Hindmarsh.

6 recordsLinked to original sources
PubMed2005

Fetal and infant head circumference sexual dimorphism in primates.

Studies have shown that after controlling for the effects of body size on brain size, the brains of adult humans, rhesus monkeys, and chimpanzees differ in relative size, where males have a greater volume of cerebral tissue than females. We assess whether head circumference sexual dimorphism is present during early development by evaluating sex differences in relative head circumference in living fetuses and infants within the first year of life. Head circumference is used as a proxy for brain size in the fetus and infant. Femur length is used as a proxy for body length in the fetus. Ultrasonography was used to obtain fetal measures, and anthropometry was used to obtain postnatal measures in humans, rhesus monkeys, baboons, and common marmosets. We show that statistically significant but low levels of head circumference sexual dimorphism are present in humans, rhesus monkeys, and baboons in early life. On average, males have head circumferences about 2% larger than females of comparable femur/body length in humans, rhesus monkeys, and baboons. No evidence for head circumference sexual dimorphism in the common marmoset was found. Dimorphism was present across all body size ranges. We suggest that head circumference sexual dimorphism emerges largely postnatally and increases throughout maturation, particularly in humans who reach adult dimorphism values greater than the monkeys. We suggest that brain dimorphism is not likely to impose an additional energetic burden to the gestating or lactating mother. Finally, some of the problems with ascribing functional significance to brain size sexual dimorphism are discussed, and the energetic implications for brain size sexual dimorphism in infancy are assessed.

Animals↗
PubMed2005

A cross-sectional international survey of continuous subcutaneous insulin infusion in 377 children and adolescents with type 1 diabetes mellitus from 10 countries.

OBJECTIVE: To document current practices using continuous subcutaneous insulin infusion (CSII) by downloading electronically the 90-d pump data held within the pump memory and relating that to clinical data from children and adolescents in different pediatric diabetes centers from Europe and Israel. METHODS: Data of patients (1-18 yr) treated with CSII in 23 centers from nine European countries and Israel were recorded with the encapture software (PEC International, Frankfurt, Germany). The number of patients who participated was 377 (48% female; mean diabetes duration +/- SD: 6.8 +/- 3.7 yr; age: 12.9 +/- 3.8 yr, preschool n = 33; prepubertal n = 95; adolescent n = 249; CSII duration: 1.6 +/- 1.2 yr; local HbA1c: 8.1 +/- 1.2%). RESULTS: The total insulin dose was lower than previously reported for injection therapy (0.79 +/- 0.20 U/kg/d). Covariance coefficient of daily total insulin was high in all age groups (adolescents 19 +/- 9%, prepubertal 18 +/- 8 and preschool 17 +/- 8). The distribution of basal insulin infusion rates over 24 hr (48 +/- 12% of total dose) varied significantly between centers and age groups. The number of boluses per day (7 +/- 3) was not significantly different between the age groups (average daily bolus amount: 0.42 +/- 0.16 U/kg). The rate of severe hypoglycemia (coma/convulsions) was 12.4 episodes per 100 patient-years and the number of diabetes-related hospital days was 124 per 100 patient-years. DISCUSSION: Pediatric CSII patients show a high variability in their insulin therapy. This relates both to age-dependent differences in the distribution of basal insulin as to the age-independent day-to-day variation in prandial insulin.

Adolescent↗
PubMed2003

Estimation and testing of parent-of-origin effects for quantitative traits.

Recent progress in developing family-based association methods has extended their use to the analysis of quantitative traits in the offspring and to the estimation, for dichotomous traits, of the relative contribution of genetic and environmental mechanisms for parent-of-origin effects. However, many traits of interest are not naturally measured on a binary scale yet are suspected or known to be influenced by imprinted genes, and there is consequent interest in seeking evidence for parent-of-origin effects at these loci. Here we show how simple linear models can be used to estimate these parent-of-origin effects for a broad class of phenotypes; in particular, normally distributed quantitative traits are easily dealt with.

Female↗
PubMedDate not supplied

Prenatal hormones and postnatal socialization by parents as determinants of male-typical toy play in girls with congenital adrenal hyperplasia.

Toy choices of 3- to 10-year-old children with congenital adrenal hyperplasia (CAH) and of their unaffected siblings were assessed. Also assessed was parental encouragement of sex-typed toy play. Girls with CAH displayed more male-typical toy choices than did their unaffected sisters, whereas boys with and without CAH did not differ. Mothers and fathers encouraged sex-typical toy play in children with and without CAH. However, girls with CAH received more positive feedback for play with girls' toys than did unaffected girls. Data show that increased male-typical toy play by girls with CAH cannot be explained by parental encouragement of male-typical toy play. Although parents encourage sex-appropriate behavior, their encouragement appears to be insufficient to override the interest of girls with CAH in cross-sexed toys.

Adrenal Hyperplasia, Congenital↗