SAMBA, a plant-specific anaphase-promoting complex/cyclosome regulator is involved in early development and A-type cyclin stabilization

The anaphase-promoting complex/cyclosome (APC/C) is a large multiprotein E3 ubiquitin ligase involved in ubiquitin-dependent proteolysis of key cell cycle regulatory proteins, including the destruction of mitotic cyclins at the metaphase-to-anaphase transition. Despite its importance, the role of the APC/C in plant cells and the regulation of its activity during cell division remain poorly understood. Here, we describe the identification of a plant-specific negative regulator of the APC/C complex, designated SAMBA. In Arabidopsis thaliana, SAMBA is expressed during embryogenesis and early plant development and plays a key role in organ size control. Samba mutants produced larger seeds, leaves, and roots, which resulted from enlarged root and shoot apical meristems, and, additionally, they had a reduced fertility attributable to a hampered male gametogenesis. Inactivation of SAMBA stabilized A2-type cyclins during early development. Our data suggest that SAMBA regulates cell proliferation during early development by targeting CYCLIN A2 for APC/C-mediated proteolysis.     

Stroke prevention in atrial fibrillation: current status and emerging therapies

Stroke is the most common cardiovascular disorder after heart disease, with a high mortality and often poor quality of life in survivors. Atrial fibrillation (AF), the most commonly occurring sustained cardiac arrhythmia increases the risk of stroke by five. However, stroke risk is not homogeneous and varies with associated morbidities and risk factors. Risk assessment scores have been developed and according to the calculated level of risk, guidelines recommend treatment with antithrombotic agents, preferably vitamin K antagonists (VKA). Despite these recommendations many patients with AF do not receive adequate thromboprophylaxis. The presence of AF is often not recognized and VKA are underused due to doctor- or patient-related factors and intrinsic disadvantages of these drugs. An awareness campaign for the diagnosis of AF is warranted, highlighting the risk of stroke. Novel anticoagulants that largely overcome many of the limitations of vitamin K antagonists are becoming available.     

Identification of rare copy number variants in high burden schizophrenia families

Over the last years, genome‐wide studies consistently showed an increased burden of rare copy number variants (CNVs) in schizophrenia patients, supporting the “common disease, rare variant” hypothesis in at least a subset of patients. We hypothesize that in families with a high burden of disease, and thus probably a high genetic load influencing disease susceptibility, rare CNVs might be involved in the etiology of schizophrenia. We performed a genome‐wide CNV analysis in the index patients of eight families with multiple schizophrenia affected members, and consecutively performed a detailed family analysis for the most relevant CNVs. One index patient showed a DRD5 containing duplication. A second index patient presented with an NRXN1 containing deletion and two adjacent duplications containing MYT1L and SNTG2. Detailed analysis in the subsequent families showed segregation of the identified CNVs. With this study we show the importance of screening high burden families for rare CNVs, which will not only broaden our knowledge concerning the molecular genetic mechanisms involved in schizophrenia but also allow the use of the obtained genetic data to provide better clinical care to these families in general and to non‐symptomatic causal CNV carriers in particular. © 2013 Wiley Periodicals, Inc.     

Fibrous Component of the Temporomandibular Joint Disk

This article describes the spatial arrangement of collagen fibrils in the articular disk of the normal human temporomandibular joint (TMJ). Disks obtained at necropsy were examined by light microscopy and scanning electron microscopy. Observations by light microscopy showed dense cartilaginous tissue composed of collagen fiber bundles running in all directions. Observations by scanning electron microscopy revealed a network of collagen fibrils which were predominantly organized in bundles. In the surface layers an anteroposterior orientation was detectable. The authors concluded that the fibrous component of the TMJ articular disk is composed of collagen fibrils, organized in a three-dimensional network and able to resist compression forces due to loading.     

Electromyography Before and After Treatment of TMJ Dysfunction

The patient described in this article suffered from pain in the right side of her face for five years before she saw the authors. Earlier treatment with medication and neurosurgery had not been successful. The authors used electromyography to examine the disturbed muscle function and to investigate a possible cause for the pain in the muscles of mastication. The silent periods of the patient's muscles were measured before and after treatment, since it is known from the literature that the EMG silent periods may be elongated in patients with TMJ dysfunction or occlusal irregularities. The coordination of both heads of this patient's lateral pterygoid muscles were bilaterally investigated before and after treatment. Treatment consisted of splint therapy and selective grinding. Oral rehabilitation was also undertaken, beginning three months after the disappearance of the patient's symptoms.     

Affective Decision-Making Is Predictive of Three-Month Relapse in Polysubstance-Dependent Alcoholics

Background/Aims: Common and long-lasting deficits in decision-making in polysubstance-dependent alcoholics (PSA) reflect neurobiological alterations that define the chronic nature of addiction. These deficits affect goal-directed behavior and might be critical risk factors predicting relapse in PSA. Methods: The Delay Discounting Task (DDT) and the Iowa Gambling Task (IGT) assessed the delay-discounting and decision-making skills among 37 abstinent PSA. Results: The findings indicated that IGT but not DDT performances were associated with 3-month abstinence, irrespective of the influence of personality traits and coexistent medications. Conclusion: The results show that the IGT, which assesses processes that are important in the latter stages of addiction, is ecologically more valid compared to the DDT, which assesses processes important in the early stages. They underline the importance of using neurocognitive measures to identify high relapse risk patients and emphasize the relevance of promoting new treatments.