Hyperphagia and obesity were observed in a subgroup of patients with the WAGR syndrome. selleck chemical We hypothesized that the subphenotype of obesity in the WAGR syndrome is attributable to deletions that induce haploinsufficiency of BDNF.

Methods:

We studied the relationship between genotype and body-mass index (BMI) in 33 patients with the WAGR syndrome who were recruited through the International WAGR Syndrome Association. The extent of each deletion was determined with the use of oligonucleotide comparative genomic hybridization.

Results: Deletions of chromosome 11p in the patients studied ranged from 1.0 to 26.5 Mb; 58% of the patients had heterozygous BDNF deletions. These patients had significantly higher BMI z scores throughout childhood than did patients with intact BDNF (mean [+/-SD] z score at 8 to 10 years of age, 2.08+/-0.45 in patients with heterozygous BDNF deletions vs. 0.88+/-1.28

in patients without BDNF deletions; P=0.03). By 10 years of age, 100% of the patients Poziotinib with heterozygous BDNF deletions (95% confidence interval [CI], 77 to 100) were obese (BMI greater/equal 95th percentile for age and sex) as compared with 20% of persons without BDNF deletions (95% CI, 3 to 56; P<0.001). The critical region for childhood-onset obesity in the WAGR syndrome was located within 80 kb of exon 1 of BDNF. Serum BDNF concentrations were approximately 50% lower among the patients with heterozygous BDNF deletions (P=0.001).

Conclusions: Among persons with the WAGR syndrome, BDNF haploinsufficiency is associated with lower levels of serum BDNF and with childhood-onset obesity; thus, BDNF may be important for energy homeostasis in humans. (ClinicalTrials.gov number, NCT00006073.).”
“According to Spence, the learning researcher’s task is to explain the relationship between experimental

variables and behavior changes occurring however with practice. Spence eschewed biological speculation. In contrast, for a biologist, “”explanation”" consists of ascertaining how the observed behavior increases reproductive success. Fundamental to achieving reproductive success is survival to sexual maturity, and such survival depends on homeostatic mechanisms attenuating the effects of physiological disturbances that threaten existence. Drugs are one way of disrupting homeostatic functioning, and studies of drug effects indicate that homeostatic mechanisms are engaged not just by pharmacological perturbations, but also by stimuli that signal such perturbations. Similarly, we attenuate the effects of a variety of nonpharmacological stimuli by such anticipatory homeostatic adjustments. The learning researcher is a homeostasis researcher.”
“Kenneth Spence (1936,1937) formalized a quantitative, elemental approach to association theory that has had a broad and dominating influence on learning theory for many years. A set of challenges to the basic approach has spurred the subsequent evolution of elemental theory in various ways.