Citations

ABSTRACT In somatic cells, H2afx and Mdc1 are close functional partners in DNA repair and damage response. However, it is not known whether they are also involved in the maintenance of genome integrity in meiosis. By analyzing chromosome dynamics in H2afx−/− spermatocytes, we found that the synapsis of autosomes and X-Y chromosomes was impaired in a fraction of cells. Such defects correlated with an abnormal recombination profile. Conversely, Mdc1 was dispensable for the synapsis of the autosomes and played only a minor role in X-Y synapsis, compared with the action of H2afx. This suggested that those genes have non-overlapping functions in chromosome synapsis. However, we observed that both genes play a similar role in the assembly of MLH3 onto chromosomes, a key step in crossover formation. Moreover, we show that H2afx and Mdc1 cooperate in promoting the activation of the recombination-dependent checkpoint, a mechanism that restrains the differentiation of cells with unrepaired DSBs. This occurs by a mechanism that involves P53. Overall, our data show that, in male germ cells, H2afx and Mdc1 promote the maintenance of genome integrity. This article has an associated First Person interview with the first author of the paper.

Melanocortin 2 receptor accessory protein (MRAP) is highly expressed in adrenal gland and adipose tissue. In adrenal cells, MRAP is essential for adrenocorticotropic hormone (ACTH)–induced activation of the cAMP/protein kinase A (PKA) pathway by melanocortin 2 receptor (MC2R), leading to glucocorticoid production and secretion. Although ACTH was known to stimulate PKA-dependent lipolysis, the functional involvement of MRAP in adipocyte metabolism remains incompletely defined. Herein, we found that knockdown or overexpression of MRAP in 3T3-L1 adipocytes reduced or increased ACTH-induced lipolysis, respectively. Moreover, an unbiased proteomics screen and coimmunoprecipitation analysis identified Gαs as a novel interacting partner of MRAP. An MRAP mutant disabled in Gαs association failed to augment the activation of PKA and lipolytic response to ACTH. Furthermore, compared with wild-type mice, transgenic mice (aP2-MRAP) overexpressing MRAP fat specifically exhibited increased lipolytic response to ACTH. When fed a high-fat diet (HFD), the transgenic mice displayed a significant decrease in the gain of adiposity and body weight as well as an improvement in glucose and insulin tolerance. These phenotypes were accompanied by increased adipose expression of genes for mitochondrial fatty acid oxidation and thermogenesis, and overall energy expenditure. Collectively, our data strongly suggest that MRAP plays a critical role in the regulation of ACTH-induced adipose lipolysis and whole-body energy balance.

AbstractBackground/ObjectivesStudies describing treatment efficacy in pediatric morphea are lacking. Subspecialists have reached no consensus on how to optimally treat pediatric morphea. The objective of the current study was to describe the most common treatment practices of pediatric dermatologists worldwide who care for children with morphea.MethodsA survey regarding topical treatment practices of pediatric morphea, with representative case‐based scenarios, was distributed to pediatric dermatologists and results were tallied.ResultsThe survey response rate was 13.4%, with 110 respondents in the final analysis. The majority of respondents agreed on red violaceous rim (99%), increased local warmth (75%), raised borders (69%), and dermal thickening (64%) as signs of disease activity. Respondents had less agreement on sclerotic lesions (41%), scaling (43%), dyspigmentation (19%), and atrophy (13%) as signs of disease activity. Ninety‐two percent of respondents used primary therapy or monotherapy with topical medications, including 45% in linear morphea of the limbs and 37% in linear morphea of the head or neck. High‐potency topical corticosteroids were most commonly used (80%), although respondents did not agree on specific regimens. Sixteen different treatment regimens were selected as first‐line therapy for one case scenario of active disease.ConclusionThe survey found large variation in how pediatric dermatologists treat pediatric morphea. Consensus treatment guidelines developed by pediatric dermatologists and pediatric rheumatologists are urgently needed regarding the efficacy of therapies for pediatric morphea. Prospective studies of treatment efficacy in pediatric morphea are urgently needed as well.

AbstractCytomegalovirus (CMV) pneumonia causes major morbidity and mortality. Its diagnosis requires demonstration of viral cytopathic changes in tissue, entailing risks of lung biopsy. This study aimed to determine CMV viral load (VL) thresholds in bronchoalveolar lavage fluid (BALF) for diagnosis of CMV pneumonia in immunocompromised patients. CMV VL in BALF was studied in 17 patients (83% transplant recipients) and 21 control subjects with and without CMV pneumonia, respectively, using an FDA‐approved PCR assay (Cobas® AmpliPrep/Cobas TaqMan® CMV Test, Roche Molecular Systems, Inc.) calibrated to the WHO International Standard for CMV DNA (NIBSC: 09/162). Receiver operating characteristic curve analysis produced a BALF CMV VL threshold of 34 800, IU/mL with 91.7% sensitivity and 100.0% specificity for diagnosis of possible, probable, and proven CMV pneumonia in transplant patients, while a threshold of 656 000 IU/mL yielded 100% sensitivity and specificity among biopsy‐proven cases. For all immunocompromised patients, a VL threshold of 274 IU/mL was selected. VL thresholds also were normalized to BALF cell count yielding a threshold of 0.32 IU/106 cells with 91.7% sensitivity and 90.5% specificity for possible, probable, and proven CMV pneumonia in transplant recipients. Monitoring CMV VL in BALF may be a less invasive method for diagnosing CMV pneumonia in immunocompromised patients.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia affecting approximately 3 million Americans, and is a prognostic marker for stroke, heart failure and even death [1]. 12-lead electrocardiogram (ECG) is used to monitor normal sinus rhythm (NSR) and also detect AF. Although the persistent form of AF can be detected relatively easy, detecting paroxysmal AF is often a challenge since requiring continuous monitoring, which becomes expensive and cumbersome to collect lot of ECG data [1]. Several researchers have attempted to develop new methods to discriminate NSR and AF which are based on R-R interval analysis, linear methods, filtering, spectral analysis, statistical approaches such as entropy etc. which faces limitation of successfully detecting AF of all types with high sensitivity and specificity using short time ECG data [1–3]. The major issues with these approaches is that they often distort the ECG by several pre-processing steps with filters, do not provide reliable discrimination using short ECG time series data and many of them lack real-time capability that makes it difficult to trust the data for diagnosis and treatment. Both clinical and scientific communities recognize these difficulties and the necessity to develop novel methods that can enable accurate monitoring and detection of AF [2]. In addition, robust detection and classification algorithms are essential for delivering appropriate therapy for implantable cardioverter defibrillators (ICD) to provide lifesaving timely action. In this work, the authors propose and demonstrate the application of a multiscale frequency (MSF) approach [4] for accurate detection and discrimination between AF and NSR ECG traces taken from publically available Physionet database. The MSF approach takes into account the contribution from various frequencies in ECG and thus yield valuable information regarding the chaotic nature of AF. Therefore, we demonstrate that MSF can capture the complexity of AF which is associated with higher MSF value compared with NSR thus enabling robust discrimination e AF manifests itself with numerous chaotic frequencies within the body surface ECG,. We validate the feasibility of this technique to discriminate NSR from AF.