Methylmercury interferes with glucocorticoid receptor: Potential role in the mediation of developmental neurotoxicity

Methylmercury (MeHg) is a widespread environmental contaminant with established developmental neurotoxic effects. Computational models have identified glucocorticoid receptor (GR) signaling to be a key mediator behind the birth defects induced by Hg, but the mechanisms were not elucidated. Using molecular dynamics simulations, we found that MeHg can bind to the GR protein at Cys736 (located close to the ligand binding site) and distort the conformation of the ligand binging site. To assess the functional consequences of MeHg interaction with GR, we used a human cell line expressing a luciferase reporter system (HeLa AZ-GR). We found that 100 nM MeHg does not have any significant effect on GR activity alone, but the transactivation of gene expression by GR upon Dex (a synthetic GR agonist) administration was reduced in cells pre-treated with MeHg. Similar effects were found in transgenic zebrafish larvae expressing a GR reporter system (SR4G). Next we asked whether the effects of developmental exposure to MeHg are mediated by the effects on GR. Using a mutant zebrafish line carrying a loss-of-function mutation in the GR (gr^S357) we could show that the effects of developmental exposure to 2.5 nM MeHg are mitigated in absence of functional GR signaling. Taken together, our data indicate that inhibition of GR signaling may have a role in the developmental neurotoxic effects of MeHg.

Genetic markers associated with abstinence length in alcohol-dependent subjects treated with acamprosate

Acamprosate supports abstinence in some alcohol-dependent subjects, yet predictors of response are unknown. To identify response biomarkers, we investigated associations of abstinence length with polymorphisms in candidate genes in glycine and glutamate neurotransmission pathways and genes previously implicated in acamprosate response. Association analyses were conducted in the discovery sample of 225 alcohol-dependent subjects treated with acamprosate for 3 months in community-based treatment programs in the United States. Data from 110 alcohol-dependent males treated with acamprosate in the study PREDICT were used for replication of the top association findings. Statistical models were adjusted for relevant covariates, including recruitment site and baseline clinical variables associated with response. In the discovery sample, shorter abstinence was associated with increased intensity of alcohol craving and lower number of days between the last drink and initiation of acamprosate treatment. After adjustment for covariates, length of abstinence was associated with the GRIN2B rs2058878 (P=4.6 × 10(-5)). In the replication sample, shorter abstinence was associated with increased craving, increased depressive mood score and higher alcohol consumption. Association of abstinence length with GRIN2B rs2058878 was marginally significant (P=0.0675); as in the discovery sample, the minor A allele was associated with longer abstinence. Furthermore, rs2300272, which is in strong linkage disequilibrium with rs2058878, was also associated with abstinence length (P=0.049). This is the first report of a replicated association of genetic markers with the length of abstinence in acamprosate-treated alcoholics. Investigation of the underlying mechanisms of this association and its usefulness for individualized treatment selection should follow.

[Successful coping with declining objective life style by institutionalized long-term patients. Results of a follow-up analysis of quality of life in long-term care institutions with the Zurich Quality of Life Inventory]

Measurement of quality of life in institutionalized frail patients is difficult considering the high prevalence of dementia. The Zurich quality of life inventory was developed specifically for this purpose and applied to describe longitudinally 103 institutionalized long-term care patients 3-12 months after entry: 11 slow-stream-rehabilitation patients (SSR), 16 severely dependent patients (ASL), 61 moderately dependent patients (ALL), and 15 young severely dependent patients, all of whom were assessed at least twice. The objective conditions of life deteriorated in all 4 groups, significantly in the SSR and ASL, and with high significance in the whole population from 121 +/- 54 to 139 +/- 58 (P < 0.001). Well-being did not change significantly in any of the groups or overall (from 122 +/- 59 to 117 +/- 54, p = 0.90). Deteriorating life conditions were due to a decline in clinical dementia rating, (p < 0.01) and living space diameter (p < 0.001), whereas the remaining subscores of life condition, i.e., number of falls, days of sickness, life style rating, and all subscores of well-being, i.e., number of medicines, valuation of handicap and of suffering, visual self-rating of well-being and caregivers' stress did not change significantly.