Transgenic inhibition of neuronal calcineurin activity in the forebrain facilitates fear conditioning, but inhibits the extinction of contextual fear memories

It is unclear whether protein phosphatases, which counteract the actions of protein kinases, play a beneficial role in the formation and extinction of previously acquired fear memories. In this study, we investigated the role of the calcium/calmodulin dependent phosphatase 2B, also known as calcineurin (CaN) in the formation of contextual fear memory and extinction of previously acquired contextual fear. We used a temporally regulated transgenic approach, that allowed us to selectively inhibit neuronal CaN activity in the forebrain either during conditioning or only during extinction training leaving the conditioning undisturbed. Reducing CaN activity through the expression of a CaN inhibitor facilitated contextual fear conditioning, while it impaired the extinction of previously formed contextual fear memory. These findings give the first genetic evidence that neuronal CaN plays an opposite role in the formation of contextual fear memories and the extinction of previously formed contextual fear memories. (C) 2007 Elsevier Inc. All rights reserved

Alzheimer's disease pathogenesis:The role of disturbed sleep in attenuated brain plasticity and neurodegenerative processes

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive impairments. The classical symptoms of the disease include gradual deterioration of memory and language. Epidemiological studies indicate that around 25-40% of AD patients have sleep-wake cycle disturbances. Importantly, a series of studies suggested that the relationship between AD and sleep disturbance may be complex and bidirectional. Indeed, accumulation of the extracellular neuronal protein amyloid-beta (A beta) leads to altered sleep-wake behavior in both mice and humans. At the same time, disturbances of the normal sleep-wake cycle may facilitate AD pathogenesis. This paper will review the mechanisms underlying this potential interrelated connection including locus coeruleus damage, reductions in orexin neurotransmission, alterations in melatonin levels, and elevated cytokine levels. In addition, we will also highlight how both the development of AD and sleep disturbances lead to changes in intracellular signaling pathways involved in regulating neuronal plasticity and connectivity, particularly extremes in cofilin phosphorylation. Finally, current pharmacological and nonpharmacological therapeutic approaches will be discussed

Sleep deprivation causes memory deficits by negatively impacting neuronal connectivity in hippocampal area CA1

Brief periods of sleep loss have long-lasting consequences such as impaired memory consolidation. Structural changes in synaptic connectivity have been proposed as a substrate of memory storage. Here, we examine the impact of brief periods of sleep deprivation on dendritic structure. In mice, we find that five hours of sleep deprivation decreases dendritic spine numbers selectively in hippocampal area CA1 and increased activity of the filamentous actin severing protein cofilin. Recovery sleep normalizes these structural alterations. Suppression of cofilin function prevents spine loss, deficits in hippocampal synaptic plasticity, and impairments in long-term memory caused by sleep deprivation. The elevated cofilin activity is caused by cAMP-degrading phosphodiesterase-4A5 (PDE4A5), which hampers cAMP-PKA-LIMK signaling. Attenuating PDE4A5 function prevents changes in cAMP-PKA-LIMK-cofilin signaling and cognitive deficits associated with sleep deprivation. Our work demonstrates the necessity of an intact cAMP-PDE4-PKA-LIMK-cofilin activation-signaling pathway for sleep deprivation-induced memory disruption and reduction in hippocampal spine density

Relativistically rotating dust

Dust configurations play an important role in astrophysics and are the simplest models for rotating bodies. The physical properties of the general--relativistic global solution for the rigidly rotating disk of dust, which has been found recently as the solution of a boundary value problem, are discussed.Comment: 18 pages, 11 figure

Health-Related Quality of Life in Patients with Multiple Endocrine Neoplasia Type 1

Introduction: Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine tumor syndrome characterized by the triad of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumors (pNETs), and pituitary tumors. Patients are confronted with substantial morbidity and are consequently at risk for an impaired quality of life (QOL). Meticulous assessment of QOL and associated factors in a representative population is needed to understand the full spectrum of the burden of the disease. Patients and Methods: A cross-sectional study was performed using the national Dutch MEN1 cohort. Patients with a confirmed MEN1 mutation received the SF-36 Health Related Quality of Life questionnaire and questions regarding sociodemographic and medical history. Results: A total of 227 of 285 (80%) eligible MEN1 patients returned the questionnaires. Health-related QOL scores (HRQOL) in MEN1 patients were significantly lower for the majority of subscales of the SF-36 in comparison with the general Dutch population. The most consistent predictor for HRQOL was employment status, followed by the presence of a pituitary tumor. 16% of patients harboring a pNET and 29% of patients with a pituitary tumor according to the medical records, reported that they were unaware of such a tumor. These subgroups of patients had several significant better QOL scores than patients who were aware of their pNET or pituitary tumors. Conclusion: Patients with MEN1 have an impaired QOL in comparison with the general Dutch population warranting special attention within routine care. For daily practice, physicians should be aware of their patients' impaired QOL and of the impact of unemployment on QOL

Clues For Genetic Anticipation In Multiple Endocrine Neoplasia Type 1

CONTEXT: Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant hereditary disease caused by the loss of function of the MEN1 gene, a tumor-suppressor gene that encodes the protein menin. It is characterized by the occurrence of primary hyperparathyroidism (pHPT), duodenopancreatic neuroendocrine tumors (dpNET), pituitary tumors (PIT), adrenal adenomas, and bronchopulmonary (bp-NET), thymic, and gastric neuroendocrine tumors. More insight into factors influencing the age-related penetrance of MEN1 manifestations could provide clues for more personalized screening programs. OBJECTIVE: To investigate whether genetic anticipation plays a role in the largest known MEN1 families in the Netherlands. METHODS: All Dutch MEN1 families with ≥ 10 affected members in ≥ 2 successive generations were identified. Age at detection of the different MEN1-related manifestations were compared among generations using regression analyses adjusted for competing risks. To correct for the beneficial effect of being under surveillance, manifestations occurring during surveillance were also separately compared. RESULTS: A total of 152 MEN1 patients from 10 families were included. A significantly decreased age at detection of pHPT, dpNET, PIT, and bp-NET was found in successive generations (P < 0.0001). Adjusted analyses led to the same results. CONCLUSIONS: These results suggest the presence of genetic anticipation. However, due to a risk of residual bias, the results must be interpreted with caution. After independent validation in other cohorts and further translational research investigating the molecular mechanisms explaining this phenomenon in MEN1, the results might add to future, more personalized, screening protocols and earlier screening for future generations of MEN1 patients

Development and Internal Validation of a Multivariable Prediction Model for Adrenocortical-Carcinoma-Specific Mortality

Adrenocortical carcinoma (ACC) has an incidence of about 1.0 per million per year. In general, survival of patients with ACC is limited. Predicting survival outcome at time of diagnosis is a clinical challenge. The aim of this study was to develop and internally validate a clinical prediction model for ACC-specific mortality. Data for this retrospective cohort study were obtained from the nine centers of the Dutch Adrenal Network (DAN). Patients who presented with ACC between 1 January 2004 and 31 October 2013 were included. We used multivariable Cox proportional hazards regression to compute the coefficients for the prediction model. Backward stepwise elimination was performed to derive a more parsimonious model. The performance of the initial prediction model was quantified by measures of model fit, discriminative ability, and calibration. We undertook an internal validation step to counteract the possible overfitting of our model. A total of 160 patients were included in the cohort. The median survival time was 35 months, and interquartile range (IQR) 50.7 months. The multivariable modeling yielded a prediction model that included age, modified European Network for the Study of Adrenal Tumors (mENSAT) stage, and radical resection. The c-statistic was 0.77 (95% Confidence Interval: 0.72, 0.81), indicating good predictive performance. We developed a clinical prediction model for ACC-specific mortality. ACC mortality can be estimated using a relatively simple clinical prediction model with good discriminative ability and calibration