Quantitative Whole-mount Immunofluorescence Analysis of Cardiac Progenitor Populations in Mouse Embryos

The use of ever-advancing imaging techniques has contributed broadly to our increased understanding of embryonic development. Pre-implantation development ...

Icahn School of Medicine at Mount Sinai

Matricide is an infrequent form of homicide. This paper is to present a case of matricide with typical characteristics of the act but interesting particularities as well. The perpetrator was a 43-year-old man, respected member of his community, with over compliant characteristics, eagerness in serving people and caring his parents, good social adaptation before and after the crime. He abandoned his family and work in order to better serve his old, disabled but over demanding mother who frequently insulted and humiliated him. Suddenly he came to a state of "mental confusion" and strangled her. After the crime, the perpetrator manifested the symptoms of a bipolar disorder and also received the diagnosis of dependant personality disorder. Years later, he presented again a crisis of escalating aggressive urge for which he was hospitalized. Many people and associations of his hometown actively demanded the minimal possible punishment for him. The case is discussed especially concerning: a) hypotheses about the aetiopathogeny of the act, b) the constant support provided to the perpetrator by his family and social environment.

Matricide by person with bipolar disorder and dependent overcompliant personality.

In Greece, as in other countries, major depressive disorder is underdiagnosed. Its severity, implications and outcomes are often not adequately evaluated. The Depression Outcomes Module (DOM) was developed in order to meet the need for a global assessment of this disorder. The objective of the current study was to estimate the psychometric properties of DOM in a Greek population presenting depressive symptoms. The DOM was translated into Greek. Patients were examined twice (baseline and follow-up assessment). The psychometric properties of DOM were calculated. Subjects were 83 psychiatric inpatients and outpatients presenting depressive symptoms. The measures used were DOM, Structured Clinical Interview for DSM III-R (SCID) and Hamilton Rating Scale for Depression (Ham-D). The results were: (a) baseline assessment: test-retest reliability k = 0.90, internal consistency 0.93, sensitivity 97%, specificity 90%; (b) follow up assessment: test-retest reliability k = 0.89, sensitivity 81% and specificity 67%. Recovery from depression detected by DOM at the follow-up was significantly correlated both with pharmacotherapy and with a combination of pharmacotherapy and supportive psychotherapy. It was concluded that the Greek version of DOM is a comprehensive, useful instrument for diagnosing, assessing depression and evaluating its outcomes.

Translation and validation of the Depression Outcomes Module (DOM) in Greece.

The aim of this paper is to report on the Greek version of the Derogatis Psychiatric Rating Scale (DPRS) and its validity and reliability when administered to a Greek sample. The DPRS is a clinician-rated measure of psychiatric symptoms with nine basic and eight complementary symptom dimensions and a Global Pathology Index.

Reliability and validity of the Greek version of the Derogatis Psychiatric Rating Scale (DPRS).

The persistent or "late" phase of long-term potentiation (L-LTP), which requires protein synthesis, can be induced by relatively intense synaptic activity. The ability of such strong synaptic protocols to engage the translational machinery and produce plasticity-related proteins, while weaker protocols activate only posttranslational processes and transient potentiation (early LTP; E-LTP), is not understood. Among the major translation control pathways in neurons, the stimulation of mammalian target of rapamycin (mTOR) is a key event in the induction of L-LTP. We report that mTOR is tonically suppressed in rat hippocampus under resting conditions, a consequence of the basal activity of glycogen synthetase kinase 3 (GSK3). This suppression could be overcome by weak synaptic stimulation in the presence of the β-adrenergic agonist isoproterenol, a combination that induced L-LTP, and activation of mTOR coincided with the Akt-mediated phosphorylation of GSK3. Surprisingly, while isoproterenol alone elevated Akt activity, it failed to increase GSK3 phosphorylation or mTOR signaling, showing that Akt was uncoupled from these effectors in the absence of synaptic stimulation. With the addition of weak stimulation, Akt signaled to GSK3 and mTOR, a gating effect that was mediated by voltage-dependent Ca(2+) channels and the Wnt pathway. mTOR could be stimulated by pharmacological inhibition, enabling weak HFS to induce L-LTP. These results establish GSK3 as an integrator of Akt and Wnt signals and suggest that overcoming GSK3-mediated suppression of mTOR is a key event in the induction of L-LTP by synaptic activity.

Synaptic stimulation of mTOR is mediated by Wnt signaling and regulation of glycogen synthetase kinase-3.

A fundamental question in G protein coupled receptor biology is how a single ligand acting at a specific receptor is able to induce a range of signaling that results in a variety of physiological responses. We focused on Type 1 cannabinoid receptor (CB₁R) as a model GPCR involved in a variety of processes spanning from analgesia and euphoria to neuronal development, survival and differentiation. We examined receptor dimerization as a possible mechanism underlying expanded signaling responses by a single ligand and focused on interactions between CB₁R and delta opioid receptor (DOR). Using co-immunoprecipitation assays as well as analysis of changes in receptor subcellular localization upon co-expression, we show that CB₁R and DOR form receptor heteromers. We find that heteromerization affects receptor signaling since the potency of the CB₁R ligand to stimulate G-protein activity is increased in the absence of DOR, suggesting that the decrease in CB₁R activity in the presence of DOR could, at least in part, be due to heteromerization. We also find that the decrease in activity is associated with enhanced PLC-dependent recruitment of arrestin3 to the CB₁R-DOR complex, suggesting that interaction with DOR enhances arrestin-mediated CB₁R desensitization. Additionally, presence of DOR facilitates signaling via a new CB₁R-mediated anti-apoptotic pathway leading to enhanced neuronal survival. Taken together, these results support a role for CB₁R-DOR heteromerization in diversification of endocannabinoid signaling and highlight the importance of heteromer-directed signal trafficking in enhancing the repertoire of GPCR signaling.

Receptor heteromerization expands the repertoire of cannabinoid signaling in rodent neurons.

Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder, characterized by pathological aggregates of amyloid peptide-β (Aβ) and tau protein. Currently available therapies mediate AD symptoms without modifying disease progression. Polyphenol-rich diets are reported to reduce the risk for AD.

Cocoa extracts reduce oligomerization of amyloid-β: implications for cognitive improvement in Alzheimer's disease.

Turnover and exchange of nucleosomal histones and their variants, a process long believed to be static in post-replicative cells, remains largely unexplored in brain. Here, we describe a novel mechanistic role for HIRA (histone cell cycle regulator) and proteasomal degradation-associated histone dynamics in the regulation of activity-dependent transcription, synaptic connectivity, and behavior. We uncover a dramatic developmental profile of nucleosome occupancy across the lifespan of both rodents and humans, with the histone variant H3.3 accumulating to near-saturating levels throughout the neuronal genome by mid-adolescence. Despite such accumulation, H3.3-containing nucleosomes remain highly dynamic-in a modification-independent manner-to control neuronal- and glial-specific gene expression patterns throughout life. Manipulating H3.3 dynamics in both embryonic and adult neurons confirmed its essential role in neuronal plasticity and cognition. Our findings establish histone turnover as a critical and previously undocumented regulator of cell type-specific transcription and plasticity in mammalian brain.

Nikos Tzavaras

Microscopy Core

Icahn School of Medicine at Mount Sinai

Quantitative Whole-mount Immunofluorescence Analysis of Cardiac Progenitor Populations in Mouse Embryos

Nikos Tzavaras

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Microscopy Core

Icahn School of Medicine at Mount Sinai

Quantitative Whole-mount Immunofluorescence Analysis of Cardiac Progenitor Populations in Mouse Embryos

Microscopy Core