Activation of cerebral Ras-related C3 botulinum toxin substrate (Rac) 1 promotes post-ischemic stroke functional recovery in aged mice.

Brain functional impairment after stroke is common; however, the molecular mechanisms of post-stroke recovery remain unclear. It is well-recognized that age is the most important independent predictor of poor outcomes after stroke as older patients show poorer functional outcomes following stroke. Mounting evidence suggests that axonal regeneration and angiogenesis, the major forms of brain plasticity responsible for post-stroke recovery, diminished with advanced age. Previous studies suggest that Ras-related C3 botulinum toxin substrate (Rac) 1 enhances stroke recovery as activation of Rac1 improved behavior recovery in a young mice stroke model. Here, we investigated the role of Rac1 signaling in long-term functional recovery and brain plasticity in an aged (male, 18 to 22 months old C57BL/6J) brain after ischemic stroke. We found that as mice aged, Rac1 expression declined in the brain. Delayed overexpression of Rac1, using lentivirus encoding Rac1 injected day 1 after ischemic stroke, promoted cognitive (assessed using novel object recognition test) and sensorimotor (assessed using adhesive removal tests) recovery on days 14-28. This was accompanied by the increase of neurite and proliferative endothelial cells in the peri-infarct zone assessed by immunostaining. In a reverse approach, pharmacological inhibition of Rac1 by intraperitoneal injection of Rac1 inhibitor NSC23766 for 14 successive days after ischemic stroke worsened the outcome with the reduction of neurite and proliferative endothelial cells. Furthermore, Rac1 inhibition reduced the activation of p21-activated kinase 1, the protein level of brain-derived neurotrophic factor, and increased the protein level of glial fibrillary acidic protein in the ischemic brain on day 28 after stroke. Our work provided insight into the mechanisms behind the diminished plasticity after cerebral ischemia in aged brains and identified Rac1 as a potential therapeutic target for improving functional recovery in the older adults after stroke.

User Utility Maximization in Narrowband Internet of Things for Prioritized Healthcare Applications.

Narrowband Internet of Things (NB-IoT) is a promising technology for healthcare applications since it reduces the latency necessary in acquiring healthcare data from patients, as well as handling remote patients. Due to the interference, limited bandwidth, and heterogeneity of generated data packets, developing a data transmission framework that offers differentiated Quality of Services (QoS) to the critical and non-critical data packets is challenging. The existing literature studies suffer from insufficient access scheduling considering heterogeneous data packets and relationship among them in healthcare applications. In this paper, we develop an optimal resource allocation framework for NB-IoT that maximizes a user's utility through event prioritization, rate enhancement, and interference mitigation. The proposed Priority Aware Utility Maximization (PAUM) system also ensures weighted fair access to resources. The suggested system outperforms the state-of-the-art works significantly in terms of utility, delay, and fair resource distribution, according to the findings of the performance analysis performed in NS-3.

A Novel Method to Identify Pneumonia through Analyzing Chest Radiographs Employing a Multichannel Convolutional Neural Network.

Pneumonia is a virulent disease that causes the death of millions of people around the world. Every year it kills more children than malaria, AIDS, and measles combined and it accounts for approximately one in five child-deaths worldwide. The invention of antibiotics and vaccines in the past century has notably increased the survival rate of Pneumonia patients. Currently, the primary challenge is to detect the disease at an early stage and determine its type to initiate the appropriate treatment. Usually, a trained physician or a radiologist undertakes the task of diagnosing Pneumonia by examining the patient's chest X-ray. However, the number of such trained individuals is nominal when compared to the 450 million people who get affected by Pneumonia every year. Fortunately, this challenge can be met by introducing modern computers and improved Machine Learning techniques in Pneumonia diagnosis. Researchers have been trying to develop a method to automatically detect Pneumonia using machines by analyzing and the symptoms of the disease and chest radiographic images of the patients for the past two decades. However, with the development of cogent Deep Learning algorithms, the formation of such an automatic system is very much within the realms of possibility. In this paper, a novel diagnostic method has been proposed while using Image Processing and Deep Learning techniques that are based on chest X-ray images to detect Pneumonia. The method has been tested on a widely used chest radiography dataset, and the obtained results indicate that the model is very much potent to be employed in an automatic Pneumonia diagnosis scheme.

Regulation of cardiac fibroblast-mediated maladaptive ventricular remodeling by ß-arrestins.

Cardiac fibroblasts (CF) play a critical role in post-infarction remodeling which can ultimately lead to pathological fibrosis and heart failure. Recent evidence demonstrates that remote (non-infarct) territory fibrosis is a major mechanism for ventricular dysfunction and arrhythmogenesis. ß-arrestins are important signaling molecules involved in ß-adrenergic receptor (ß-AR) desensitization and can also mediate signaling in a G protein independent fashion. Recent work has provided evidence that ß-arrestin signaling in the heart may be beneficial, however, these studies have primarily focused on cardiac myocytes and their role in adult CF biology has not been well studied. In this study, we show that ß-arrestins can regulate CF biology and contribute to pathological fibrosis. Adult male rats underwent LAD ligation to induce infarction and were studied by echocardiography. There was a significant decline in LV function at 2-12 weeks post-MI with increased infarct and remote territory fibrosis by histology consistent with maladaptive remodeling. Collagen synthesis was upregulated 2.9-fold in CF isolated at 8 and 12 weeks post-MI and ß-arrestin expression was significantly increased. ß-adrenergic signaling was uncoupled in the post-MI CF and ß-agonist-mediated inhibition of collagen synthesis was lost. Knockdown of ß-arrestin1 or 2 in the post-MI CF inhibited transformation to myofibroblasts as well as basal and TGF-ß-stimulated collagen synthesis. These data suggest that ß-arrestins can regulate CF biology and that targeted inhibition of these signaling molecules may represent a novel approach to prevent post-infarction pathological fibrosis and the transition to HF.

Inhibition of Postinfarction Ventricular Remodeling by High Molecular Weight Polyethylene Glycol.

BACKGROUND: Myocardial infarction (MI) is a major etiology for the development of heart failure. We have previously shown that high molecular weight polyethylene glycol (PEG) can protect cardiac myocytes from hypoxia-reoxygenation injury in vitro. In this study, we investigated the potential protective effects of 15-20 kD PEG postinfarction without reperfusion. METHODS: One milliliter of PEG 15-20 was delivered intravenously following permanent left anterior descending ligation in adult male rats with phosphate buffer saline (PBS) as control (n = 9 in each group). Echocardiography was performed at baseline and at 8 wk post-MI. Left ventricles (LVs) were harvested to quantify fibrosis, apoptosis, cell survival signaling, regulation of ß-adrenergic signaling, and caveolin (Cav) expression. RESULTS: The PEG group had significant recovery of LV function at 8 wk compared with the PBS group. There was less LV fibrosis in both the infarct and remote territory. Cell survival signaling was upregulated in the PEG group with increased Akt and ERK phosphorylation. PEG inhibited apoptosis as measured by terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick-end labeling positive nuclei and caspase-3 activity. There was maintenance of Cav-1, Cav-2, and Cav-3 expression following PEG treatment versus a decline in the PBS group. Negative regulators of ß-adrenergic signaling, G protein-coupled receptor kinase-2, and ß-arrestin 1 and 2 were all upregulated in PBS-treated samples compared to normal control; however, PEG treatment led to decreased expression. CONCLUSIONS: These data suggest that PEG 15-20 may have significant protective effects post-MI even in the setting of no acute reperfusion. Upregulation of Cav expression appears to be a key mechanism for the beneficial effects of PEG on ventricular remodeling and function.

Self-Coexistence among IEEE 802.22 Networks: Distributed Allocation of Power and Channel.

Ensuring self-coexistence among IEEE 802.22 networks is a challenging problem owing to opportunistic access of incumbent-free radio resources by users in co-located networks. In this study, we propose a fully-distributed non-cooperative approach to ensure self-coexistence in downlink channels of IEEE 802.22 networks. We formulate the self-coexistence problem as a mixed-integer non-linear optimization problem for maximizing the network data rate, which is an NP-hard one. This work explores a sub-optimal solution by dividing the optimization problem into downlink channel allocation and power assignment sub-problems. Considering fairness, quality of service and minimum interference for customer-premises-equipment, we also develop a greedy algorithm for channel allocation and a non-cooperative game-theoretic framework for near-optimal power allocation. The base stations of networks are treated as players in a game, where they try to increase spectrum utilization by controlling power and reaching a Nash equilibrium point. We further develop a utility function for the game to increase the data rate by minimizing the transmission power and, subsequently, the interference from neighboring networks. A theoretical proof of the uniqueness and existence of the Nash equilibrium has been presented. Performance improvements in terms of data-rate with a degree of fairness compared to a cooperative branch-and-bound-based algorithm and a non-cooperative greedy approach have been shown through simulation studies.

Regulation of mitochondrial oxidative stress by ß-arrestins in cultured human cardiac fibroblasts.

Oxidative stress in cardiac fibroblasts (CFs) promotes transformation to myofibroblasts and collagen synthesis leading to myocardial fibrosis, a precursor to heart failure (HF). NADPH oxidase 4 (Nox4) is a major source of cardiac reactive oxygen species (ROS); however, mechanisms of Nox4 regulation are unclear. ß-arrestins are scaffold proteins that signal in G-protein-dependent and -independent pathways; for example, in ERK activation. We hypothesize that ß-arrestins regulate oxidative stress in a Nox4-dependent manner and increase fibrosis in HF. CFs were isolated from normal and failing adult human left ventricles. Mitochondrial ROS/superoxide production was quantitated using MitoSox. ß-arrestin and Nox4 expressions were manipulated using adenoviral overexpression or short interfering RNA (siRNA)-mediated knockdown. Mitochondrial oxidative stress and Nox4 expression in CFs were significantly increased in HF. Nox4 knockdown resulted in inhibition of mitochondrial superoxide production and decreased basal and TGF-ß-stimulated collagen and α-SMA expression. CF ß-arrestin expression was upregulated fourfold in HF. ß-arrestin knockdown in failing CFs decreased ROS and Nox4 expression by 50%. ß-arrestin overexpression in normal CFs increased mitochondrial superoxide production twofold. These effects were prevented by inhibition of either Nox or ERK. Upregulation of Nox4 seemed to be a primary mechanism for increased ROS production in failing CFs, which stimulates collagen deposition. ß-arrestin expression was upregulated in HF and plays an important and newly identified role in regulating mitochondrial superoxide production via Nox4. The mechanism for this effect seems to be ERK-mediated. Targeted inhibition of ß-arrestins in CFs might decrease oxidative stress as well as pathological cardiac fibrosis.

High-molecular-weight polyethylene glycol inhibits myocardial ischemia-reperfusion injury in vivo.

OBJECTIVES: Cardiac ischemia-reperfusion (I-R) injury remains a significant problem as there are no therapies available to minimize the cell death that can lead to impaired function and heart failure. We have shown that high-molecular-weight polyethylene glycol (PEG) (15-20 kD) can protect cardiac myocytes in vitro from hypoxia-reoxygenation injury. In this study, we investigated the potential protective effects of PEG in vivo. METHODS: Adult rats underwent left anterior descending artery occlusion for 60 minutes followed by 48 hours or 4 weeks of reperfusion. One milliliter of 10% PEG solution or phosphate-buffered saline (PBS) control (n = 10 per group) was administered intravenously (IV) immediately before reperfusion. RESULTS: Fluorescein-labeled PEG was robustly visualized in the myocardium 1 hour after IV delivery. The PEG group had significant recovery of left ventricular ejection fraction at 4 weeks versus a 25% decline in the PBS group (P < .01). There was 50% less LV fibrosis in the PEG group versus PBS with smaller peri-infarct and remote territory fibrosis (P < .01). Cell survival signaling was upregulated in the PEG group with increased Akt (3-fold, P < .01) and ERK (4-fold, P < .05) phosphorylation compared to PBS controls at 48 hours. PEG also inhibited apoptosis as measured by TUNEL-positive nuclei (56% decrease, P < .02) and caspase 3 activity (55% decrease, P < .05). CONCLUSIONS: High-molecular-weight PEG appears to have a significant protective effect from I-R injury in the heart when administered IV immediately before reperfusion. This may have important clinical translation in the setting of acute coronary revascularization and myocardial protection in cardiac surgery.

Moving target tracking through distributed clustering in directional sensor networks.

The problem of moving target tracking in directional sensor networks (DSNs) introduces new research challenges, including optimal selection of sensing and communication sectors of the directional sensor nodes, determination of the precise location of the target and an energy-efficient data collection mechanism. Existing solutions allow individual sensor nodes to detect the target's location through collaboration among neighboring nodes, where most of the sensors are activated and communicate with the sink. Therefore, they incur much overhead, loss of energy and reduced target tracking accuracy. In this paper, we have proposed a clustering algorithm, where distributed cluster heads coordinate their member nodes in optimizing the active sensing and communication directions of the nodes, precisely determining the target location by aggregating reported sensing data from multiple nodes and transferring the resultant location information to the sink. Thus, the proposed target tracking mechanism minimizes the sensing redundancy and maximizes the number of sleeping nodes in the network. We have also investigated the dynamic approach of activating sleeping nodes on-demand so that the moving target tracking accuracy can be enhanced while maximizing the network lifetime. We have carried out our extensive simulations in ns-3, and the results show that the proposed mechanism achieves higher performance compared to the state-of-the-art works.

RAF1 mutations in childhood-onset dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is a highly heterogeneous trait with sarcomeric gene mutations predominating. The cause of a substantial percentage of DCMs remains unknown, and no gene-specific therapy is available. On the basis of resequencing of 513 DCM cases and 1,150 matched controls from various cohorts of distinct ancestry, we discovered rare, functional RAF1 mutations in 3 of the cohorts (South Indian, North Indian and Japanese). The prevalence of RAF1 mutations was ~9% in childhood-onset DCM cases in these three cohorts. Biochemical studies showed that DCM-associated RAF1 mutants had altered kinase activity, resulting in largely unaltered ERK activation but in AKT that was hyperactivated in a BRAF-dependent manner. Constitutive expression of these mutants in zebrafish embryos resulted in a heart failure phenotype with AKT hyperactivation that was rescued by treatment with rapamycin. These findings provide new mechanistic insights and potential therapeutic targets for RAF1-associated DCM and further expand the clinical spectrum of RAF1-related human disorders.

An endogenously produced fragment of cardiac myosin-binding protein C is pathogenic and can lead to heart failure.

RATIONALE: A stable 40-kDa fragment is produced from cardiac myosin-binding protein C when the heart is stressed using a stimulus, such as ischemia-reperfusion injury. Elevated levels of the fragment can be detected in the diseased mouse and human heart, but its ability to interfere with normal cardiac function in the intact animal is unexplored. OBJECTIVE: To understand the potential pathogenicity of the 40-kDa fragment in vivo and to investigate the molecular pathways that could be targeted for potential therapeutic intervention. METHODS AND RESULTS: We generated cardiac myocyte-specific transgenic mice using a Tet-Off inducible system to permit controlled expression of the 40-kDa fragment in cardiomyocytes. When expression of the 40-kDa protein is induced by crossing the responder animals with tetracycline transactivator mice under conditions in which substantial quantities approximating those observed in diseased hearts are reached, the double-transgenic mice subsequently experience development of sarcomere dysgenesis and altered cardiac geometry, and the heart fails between 12 and 17 weeks of age. The induced double-transgenic mice had development of cardiac hypertrophy with myofibrillar disarray and fibrosis, in addition to activation of pathogenic MEK-ERK pathways. Inhibition of MEK-ERK signaling was achieved by injection of the mitogen-activated protein kinase (MAPK)/ERK inhibitor U0126. The drug effectively improved cardiac function, normalized heart size, and increased probability of survival. CONCLUSIONS: These results suggest that the 40-kDa cardiac myosin-binding protein C fragment, which is produced at elevated levels during human cardiac disease, is a pathogenic fragment that is sufficient to cause hypertrophic cardiomyopathy and heart failure.

Characterization of a novel KRAS mutation identified in Noonan syndrome.

Noonan syndrome (NS) is the most common non-chromosomal syndrome seen in children and is characterized by short stature, dysmorphic facial features, chest deformity, a wide range of congenital heart defects and developmental delay of variable degree. Mutations in the Ras/mitogen-activated protein kinase (MAPK) signaling pathways cause about 70% of NS cases with a KRAS mutation present in about 2%. In a cohort of 65 clinically confirmed NS patients of Japanese origin, we screened for mutations in the RAS genes by direct sequencing. We found a novel mutation in KRAS with an amino acid substitution of asparagine to serine at codon 116 (N116S). We analyzed the biological activity of this mutant by ectopic expression of wild-type or mutant KRAS. NS-associated KRAS mutation resulted in Erk activation and active Ras-GTP levels, and exhibited mild cell proliferation. In addition, kras-targeted morpholino knocked-down zebrafish embryos caused heart and craniofacial malformations, while the expression of mutated kras resulted in maldevelopment of the heart. Our findings implicate that N116S change in KRAS is a hyperactive mutation which is a causative agent of NS through maldevelopment of the heart.

Data-centric multiobjective QoS-aware routing protocol for body sensor networks.

In this paper, we address Quality-of-Service (QoS)-aware routing issue for Body Sensor Networks (BSNs) in delay and reliability domains. We propose a data-centric multiobjective QoS-Aware routing protocol, called DMQoS, which facilitates the system to achieve customized QoS services for each traffic category differentiated according to the generated data types. It uses modular design architecture wherein different units operate in coordination to provide multiple QoS services. Their operation exploits geographic locations and QoS performance of the neighbor nodes and implements a localized hop-by-hop routing. Moreover, the protocol ensures (almost) a homogeneous energy dissipation rate for all routing nodes in the network through a multiobjective Lexicographic Optimization-based geographic forwarding. We have performed extensive simulations of the proposed protocol, and the results show that DMQoS has significant performance improvements over several state-of-the-art approaches.

Identification of a Gene Sharing a Promoter and Peroxisome Proliferator-Response Elements With Acyl-CoA Oxidase Gene.

Many mammalian genes are clustered on the genomes, and hence the genes in the same cluster can be regulated through a common regulatory element. We indeed showed previously that the perilipin/PEX11alpha gene pair is transactivated tissue-selectively by PPARgamma and PPARalpha, respectively, through a common binding site. In the present study, we identified a gene, named GSPA, neighboring a canonical PPAR target, acyl-CoA oxidase (AOX) gene. GSPA expression was induced by a peroxisome proliferator, Wy14,643, in the liver of wild-type mice, but not PPARalpha-null mice. GSPA and AOX share the promoter and two peroxisome proliferator-response elements. GSPA mRNA was also found in the heart and skeletal muscle, as well as 3T3-L1 cells. GSPA encodes a protein of 161 amino acids that is enriched in 3T3-L1 cells. Even other gene pairs might be regulated through common sequence elements, and conversely it would be interesting how each gene is aptly regulated in clusters.

Estrogen receptor-related receptor gamma has an exceptionally broad specificity of DNA sequence recognition.

Estrogen receptor-related receptors (ERRs) constitute a subfamily of the nuclear hormone receptor superfamily. ERRs are closely related to estrogen receptors (ERs), but apparently lack ligand dependence. In this study, we cloned rat ERRgamma as an interacting partner of an orphan nuclear receptor, small heterodimer partner (SHP). ERRgamma exhibited significant binding affinities with a wide spectrum of sequences: inverted and direct repeat motifs composed of AGGTCA half-sites with various spacings, as well as a monovalent motif of the same sequence carrying extra T(C/G)A trinucleotides on the 5' side. On the other hand, inverted repeat spaced by three nucleotides was dominantly efficient for the binding of ERalpha. These results were mostly consistent with those of gene reporter assays. ERRgamma bound as a homodimer to all binding sequences tested, including a monovalent binding site, and ERRgamma did not heterodimerize with ERalpha. Taken together, ERRgamma recognizes a tremendously broad range of sequences as a homodimer. Finally, we found that SHP efficiently represses the transcriptional activity of ERRgamma, even at a far lower concentration than that of ERRgamma.