Estrogen‐related receptor β deletion modulates whole‐body energy balance via estrogen‐related receptor γ and attenuates neuropeptide Y gene expression

Estrogen‐related receptors (ERRs) α, β and γ are orphan nuclear hormone receptors with no known ligands. Little is known concerning the role of ERRβ in energy homeostasis, as complete ERRβ‐null mice die mid‐gestation. We generated two viable conditional ERRβ‐null mouse models to address its metabolic function. Whole‐body deletion of ERRβ in Sox2‐Cre:ERRβ^lox/lox mice resulted in major alterations in body composition, metabolic rate, meal patterns and voluntary physical activity levels. Nestin‐Cre:ERRβ^lox/lox mice exhibited decreased expression of ERRβ in hindbrain neurons, the predominant site of expression, decreased neuropeptide Y (NPY) gene expression in the hindbrain, increased lean body mass, insulin sensitivity, increased energy expenditure, decreased satiety and decreased time between meals. In the absence of ERRβ, increased ERRγ signaling decreased satiety and the duration of time between meals, similar to meal patterns observed for both the Sox2‐Cre:ERRβ^lox/lox and Nestin‐Cre:ERRβ^lox/lox strains of mice. Central and/or peripheral ERRγ signaling may modulate these phenotypes by decreasing NPY gene expression. Overall, the relative expression ratio between ERRβ and ERRγ may be important in modulating ingestive behavior, specifically satiety, gene expression, as well as whole‐body energy balance.     

Canonical transient receptor potential channel subtype 3‐mediated hair cell Ca2+ entry regulates sound transduction and auditory neurotransmission

The physiological significance of canonical transient receptor potential (TRPC) ion channels in sensory systems is rapidly emerging. Heterologous expression studies show that TRPC3 is a significant Ca²⁺ entry pathway, with dual activation via G protein‐coupled receptor (GPCR)–phospholipase C–diacylglycerol second messenger signaling, and through negative feedback, whereby a fall in cytosolic Ca²⁺ releases Ca²⁺–calmodulin channel block. We hypothesised that the latter process contributes to cochlear hair cell cytosolic Ca²⁺ homeostasis. Confocal microfluorimetry with the Ca²⁺ indicator Fluo‐4 acetoxymethylester showed that, when cytosolic Ca²⁺ was depleted, Ca²⁺ re‐entry was significantly impaired in mature TRPC3^?/? inner and outer hair cells. The impact of this disrupted Ca²⁺ homeostasis on sound transduction was assessed with the use of distortion product otoacoustic emissions (DPOAEs), which constitute a direct measure of the outer hair cell transduction that underlies hearing sensitivity and frequency selectivity. TRPC3^?/? mice showed significantly stronger DPOAE (2f₁ ? f₂) growth functions than wild‐type (WT) littermates within the frequency range of best hearing acuity. This translated to hyperacusis (decreased threshold) measured by the auditory brainstem response (ABR). TRPC3^?/? and WT mice did not differ in the levels of temporary and permanent threshold shift arising from noise exposure, indicating that potential GPCR signaling via TRPC3 is not pronounced. Overall, these data suggest that the Ca²⁺ set‐point in the hair cell, and hence membrane conductance, is modulated by TRPC3s through their function as a negative feedback‐regulated Ca²⁺ entry pathway. This TPRC3‐regulated Ca²⁺ homeostasis shapes the sound transduction input–output function and auditory neurotransmission.     

Brain imaging research: Does the science serve clinical practice?

Brain imaging represents a potent tool to characterize biomarkers, biological traits that are pathognomonic for specific neurological and neuropsychiatric disorders. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are imaging techniques used to identify alterations in the density and distribution of neurotransmitters, neuroreceptors, and transporters in specific regions of the brains of people with these disorders. Brain imaging research currently facilitates the elucidation of dysfunction of dopamine, serotonin, acetylcholine, and other substances in people with Alzheimer's and Parkinson's diseases, schizophrenia, alcoholism and other substance abuse disorders, attention deficit/hyperactivity disorder, and the syndromes of restless legs, Lesch-Nyhan, Rett, and Tourette. Thus, brain imaging research offers great potential for the diagnosis, treatment, prevention, and cure of neurological and neuropsychiatric disorders. Brain imaging research also facilitates new drug development and helps establish therapeutic doses of novel drugs. In particular, studies of specific receptors, such as the dopamine D₂ receptor, before and after the administration of doses of drugs that occupy these D₂ receptors, provide the means to determine receptor occupancy. For example, an optimal dose of D₂ antagonist antipsychotics produces occupancy of 65% to 80% of D₂ receptors, while a greater dose carries a risk of extrapyramidal side effects.     

A study of semantic treatment of three Chinese anomic patients

A treatment combining semantic feature analysis and semantic priming was carried out on three Cantonese-speaking brain-injured individuals with word-finding difficulties. Two of the participants with mild to moderate semantic impairment demonstrated significant progress on naming performance. Treatment effects also generalised to semantically related and unrelated untrained items. However, only one of these two participants was able to maintain the treatment gain for at least one month after the therapy was completed. The third patient with severe semantic deficits did not benefit from the intervention. The different outcomes of these participants to the same intervention were explained in terms of the nature of the treatment approach, the patients' underlying language deficits, and their level of cognitive abilities.     

Potassium Depolarization and Raised Calcium Induces α-Synuclein Aggregates

α-Synuclein is the key aggregating protein in Parkinson’s disease (PD), which is characterized by cytoplasmic protein inclusion bodies, termed Lewy bodies, thought to increase longevity of the host neuron by sequestering toxic soluble α-synuclein oligomers. Previous post-mortem studies have shown relative sparing of neurons in PD that are positive for the Ca²⁺ buffering protein, calbindin, and recent cell culture and in vitro studies have shown that α-synuclein aggregation can be induced by Ca²⁺. We hypothesized that depolarization with potassium resulting in raised Ca²⁺ in a PD cell culture model will lead to the formation of α-synuclein protein aggregates and that the intracellular Ca²⁺ buffer, BAPTA-AM, may suppress their formation. Live cell fluorescence microscopy was performed to monitor changes in intracellular free calcium in HEK293T, SH-SY5Y neuroblastoma or stably transfected HEK293T/α-synuclein cells. Raised intracellular free Ca²⁺ was consistently observed in cells treated with KCl, but not controls. Immunohistochemistry analysis on cells 48–72 h after K⁺ treatment revealed two subsets of cells with either large (>2 μm), perinuclear α-synuclein aggregates or multiple smaller (<2 μm), cytoplasmic accumulations. Cells pre-treated with varying concentrations of trimethadione (TMO), a calcium channel blocker, showed suppression of the Ca²⁺ transient following KCl treatment and no α-synuclein aggregates at TMO concentrations >5 μM. Quantitative analysis revealed a significant increase in the number of cells bearing α-synuclein cytoplasmic inclusions in both HEK293T/α-synuclein and SHSY-5Y cells when transient intracellular raised Ca²⁺ was induced (p = 0.001). BAPTA-AM pre-loading significantly suppressed α-synuclein aggregates (p = 0.001) and the intracellular free Ca²⁺ transient. This study indicates that raised intracellular Ca²⁺ mediated by K⁺ depolarization can lead to α-synuclein aggregation.     

Racial and ethnic disparities in the use of antipsychotic medication: a systematic review and meta-analysis

Objective

To conduct a systematic review and meta-analysis of published evidence on ethnic or racial disparities in the outpatient use versus non-use of antipsychotics and in the outpatient use of newer versus older antipsychotics.

Method

Electronic databases were searched for potentially relevant studies. Two independent reviewers conducted the review in three stages: title review, abstract review and full-text review. Included studies were those that: (a) report measures of disparity in the outpatient use of antipsychotic drugs in clearly defined racial or ethnic groups (b) have a primary focus on ethnic or racial disparities, and (c) have adjusted for factors known to influence medicine use. Odds ratios were pooled following the inverse-variance method of weighting effect sizes. I ² statistics were calculated to quantify the amount of variation that is likely due to heterogeneity between studies. Funnel plots were produced and Egger’s statistic was calculated to assess potential publication bias.

Results

No significant differences were found in the odds of using any antipsychotics among African Americans (OR = 1.01, CI = 0.99–1.02) compared with non-African Americans and among Latinos (OR = 0.98, CI = 0.86–1.13) compared with non-Latinos. Small to moderate but statistically non-significant disparities were also noted in other ethnic groups: Asians (OR = 1.10, CI = 0.88–1.36), Maoris (OR = 0.78, CI = 0.53–1.13) and Pacific Islanders (OR = 0.97, CI = 0.84–1.11). Among those who received antipsychotic medication, African Americans (OR = 0.62, CI = 0.50–0.78) and Latinos (OR = 0.77, CI = 0.73–0.81) appeared to have lower odds of receiving newer antipsychotics compared with non-African Americans and non-Latinos.

Conclusion

No significant ethnic disparities in the use versus non-use of any antipsychotics were observed, but, among those who received antipsychotic treatment, ethnic minorities were consistently less likely than non-ethnic minorities to be treated with newer antipsychotics.     

Anatomical surgical planning for oral and oropharyngeal primary carcinoma combined with adjuvant treatment where indicated is associated with improved local control

We aimed to find out whether surgical tactics that lead to a reduction in tumour-involved surgical margins also improve local control. We retrospectively reviewed a consecutive case series (n = 162) of previously untreated patients who had operations for squamous cell carcinoma (SCC) of the oral cavity or oropharynx. Extensive use was made of computed tomographic multiplanar imaging to plan primary resections. Nine patients (6%) had tumour at the resection margin. Local control at 36 months was 96%, disease-specific survival (DSS) was 86%, and overall survival (OS) was 77%. Carefully planned primary operation for SCC of the oral cavity and oropharynx to minimise tumour-involved margins combined with conventional adjuvant treatment where indicated, is associated with a high probability of local control and disease-specific survival.