Restoration of Contractile Protein Expression and Colonic Smooth Muscle Function by Hydrogen Sulfide in DMD Mice

Duchenne Muscular Dystrophy (DMD), characterized by the lack of dystrophin, results from a mutation in the Xp21 gene which encodes for the protein dystrophin that links the extracellular matrix to the actin cytoskeleton in skeletal, cardiac and smooth muscle. Slow colonic transit and chronic constipation are common in DMD patients due to the weakening of the abdominal wall muscles and gut smooth muscle. However, the cause of this hypocontractility in DMD patients and the expression of contractile proteins in smooth muscle are unknown. Expression of contractile proteins is regulated by the signaling pathways activated by excitatory (e.g., acetylcholine, ACh) and inhibitory transmitters (e.g., nitric oxide). Hydrogen sulfide (H2S) is well-known for its anti-oxidant effects; however, its utility to restore DMD-induced effects is unknown. Aim: To investigate the expression of contractile proteins and smooth muscle function in the colon of wild type mice and models of DMD (mdx and mdx/mTR mice) and the effect of H2S on these in mdx mice. Methods: Contraction of colonic segments was measured in the longitudinal orientation from 3-month old control and mdx mice, and 9-month old control and mdx/mTR mice, (mdx/mTR exhibit increased disease severity). The effect of SG1002, an orally active slow releasing H2S agent, was tested in mdx/mTR mice (40 mg/kg body weight in chow/every 3 days starting from 3 weeks to 9 months). Expression of contractile proteins was measured by qRT-PCR and western blot. Results: Expression of smoothelin, caldesmon, calponin and tropomyosin was decreased in colonic smooth muscle of mdx mice compared to control. This decrease was associated with a decrease in ACh-induced contraction in colonic segments (21 ± 3 mN/100 mg tissue in control and 3 ± 1 mN/100 mg tissue in mdx mice). To identify the specific involvement of smooth muscle dysfunction in the decrease in contraction, colonic muscle cells were isolated and contraction in response to ACh was measured by scanning micrometry and expressed as the percent decrease in cell length from control cell length. ACh-induced contraction was also inhibited in muscle cells isolated from mdx mice compared to control (43±5% in control and 27±3% in mdx mice). ACh-induced contraction was decreased in colonic segments from mdx/mTR mice (12 ± 2 mN/100 mg tissue in control versus 4 ± 1 mN/100 mg tissue in mdx/mTR) and the decrease was partly reversed by SG1002 treatment (9 ± 1 mN/100 mg tissue). mRNA expression of thin filament associated proteins was also decreased in colonic smooth muscle from mdx/mTR mice and the decrease was reversed by SG1002. These results suggest that H2S restores contractile protein mRNA expression and contraction in mdx/mTR mice. Conclusion: The data indicate that the lack of dystrophin in mdx mice adversely affects colonic smooth muscle contractility through the down regulation of contractile protein mRNA expression. Treatment of mdx/mTR mice with H2S restores contractile phenotype. Thus, H2S treatment would be an area of study in therapeutic control of DMD-induced gastrointestinal motility disorders

Resveratrol and Black Tea Polyphenol Combination Synergistically Suppress Mouse Skin Tumors Growth by Inhibition of Activated MAPKs and p53

Cancer chemoprevention by natural dietary agents has received considerable importance because of their cost-effectiveness and wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasing popularity. The present study aims to evaluate the combinatorial chemopreventive effects of resveratrol and black tea polyphenol (BTP) in suppressing two-stage mouse skin carcinogenesis induced by DMBA and TPA. Resveratrol/BTP alone treatment decreased tumor incidence by ∼67% and ∼75%, while combination of both at low doses synergistically decreased tumor incidence even more significantly by ∼89% (p<0.01). This combination also significantly regressed tumor volume and number (p<0.01). Mechanistic studies revealed that this combinatorial inhibition was associated with decreased expression of phosphorylated mitogen-activated protein kinase family proteins: extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2, p38 and increased in total p53 and phospho p53 (Ser 15) in skin tissue/tumor. Treatment with combinations of resveratrol and BTP also decreased expression of proliferating cell nuclear antigen in mouse skin tissues/tumors than their solitary treatments as determined by immunohistochemistry. In addition, histological and cell death analysis also confirmed that resveratrol and BTP treatment together inhibits cellular proliferation and markedly induces apoptosis. Taken together, our results for the first time lucidly illustrate that resveratrol and BTP in combination impart better suppressive activity than either of these agents alone and accentuate that development of novel combination therapies/chemoprevention using dietary agents will be more beneficial against cancer. This promising combination should be examined in therapeutic trials of skin and possibly other cancers

Probabilistic Discovery of Semantically Diverse Content in MANETs

Mobile ad hoc networks rely on the opportunistic interaction of autonomous nodes to form networks without the use of infrastructure. Given the radically decentralized nature of such networks, their potential for autonomous communication is significantly improved when the need for a priori consensus among the nodes is kept to a minimum. This paper addresses an issue within the domain of semantic content discovery, namely, its current reliance on the preexisting agreement between the schema of content providers and consumers. We present OntoMobil, a semantic discovery model for ad hoc networks that removes the assumption of a globally known schema and allows nodes to publish information autonomously. The model relies on the randomized dissemination and replication of metadata through a gossip protocol. Given schemas with partial similarities, the randomized metadata dissemination mechanism facilitates eventual semantic agreement and provides a substrate for the scalable discovery of content. A discovery protocol can then utilize the replicated metadata to identify content within a predictable number of hops using semantic queries. A stochastic analysis of the gossip protocol presents the different trade-offs between discoverability and replication. We evaluate the proposed model by comparing OntoMobil against a broadcast-based protocol and demonstrate that semantic discovery with proactive replication provides good scalability properties, resulting in a high discovery ratio with less overhead than a reactive nonreplicated discovery approach

OOPSLA 2002 Workshop on Pervasive Computing

With the developments in the field of wireless ad-hoc networks combined with low-cost communication and computational devices, pervasive environments are closer to reality than ever. As such environments become more prevalent, they will simply be ?invisible? to the user, and as a result, he will not distinguish wireless, ad-hoc infrastructures with wired, fixed ones. From the user perspective, the fact that the network now supports mobility means that those group-based activities enjoyed with the traditional PC-based paradigm should, of course, be available when roaming with a mobile device. In the not-so-distant future, teleconference meetings, online augmented reality gaming and other ?collaborative work" activities with mobile participants will seem perfectly reasonable

Short-term effect of field application of biochar on cation exchange capacity, pH, and electrical conductivity of sandy and clay loam temperate soils

Biochar soil amendment is known to improve soil chemical properties. Synchronized addition of biochar and mineral fertilizer nitrogen (N) could increase agronomic benefits and remedy the adverse environmental impact of fertilizer N. The objective of this study was to compare the short-term effect of a synchronized addition of biochar and fertilizer N (NB) with sole N fertilizer (NF) on cation exchange capacity (CEC), pH, and electrical conductivity (EC). We hypothesized that mixing biochar with inorganic N would improve the CEC, pH, and EC of sandy soils. Soil samples were taken at the end of the cropping season of 2018 and 2019 from Efaw and Lake Carl Blackwell (LCB), OK, USA following maize (Zea mays L.) grain harvest. The study had ten treatments and used a randomized complete block design with three replications. Biochar and N rates were 5, 10, and 15 t·ha−1, and 50, 100, and 150 kg·N·ha−1, respectively. Overall, results indicated significant improvement in CEC and pH under NB. At Efaw, CEC and pH were greater with NB by 4%, than NF while EC was lower with NB by 5%. At LCB, CEC, pH, and EC values with NB increased by 16%, 3%, and 7%, respectively compared to NF. Averaged across experimental sites, CEC, pH, and EC increased with NB by 10%, 4%, and 1%, respectively compared to NF. Significant responses of CEC to biochar addition were observed on coarse soil texture (p < 0.05). Alongside increasing the retention of nutrient cations, the significant increase in pH (p < 0.05) suggest that synchronized application of biochar and inorganic N could alleviate soil acidity. In the future, the amount of N fertilizer used in sandy soils may reduce under biochar application

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