Central core disease (CCD) and nemaline myopathy (NM) are congenital myopathies for which differential diagnosis is often based on the presence either of cores or rods. Missense mutations in the skeletal muscle ryanodine receptor gene (RYR1) have been identified in some families with CCD. Mutations in the alpha-tropomyosin and alpha-actin genes have been associated with most dominant forms of NM. Analysis of the RYR1 cDNA in a French family identified a novel Y4796C mutation that lies in the C-terminal channel-forming domain of the RyR1 protein. This mutation was linked not only to a severe and penetrant form of CCD, but also to the presence of rods in the muscle fibres and to the malignant hyperthermia susceptibility (MHS) phenotype. The Y4796C mutation was introduced into a rabbit RYR1 cDNA and expressed in HEK-293 cells. Expression of the mutant RYR1 cDNA produced channels with increased caffeine sensitivity and a significantly reduced maximal level of Ca(2+) release. Single-cell Ca(2+) analysis showed that the resting cytoplasmic level was increased by 60% in cells expressing the mutant channel. These data support the view that the rate of Ca(2+) leakage is increased in the mutant channel. The resulting chronic elevation in myoplasmic concentration is likely to be responsible for the severe expression of the disease. Haplotyping analysis indicated that the mutation arose as a neomutation in the proband. This first report of a neomutation in the RYR1 gene has strong implications for genetic linkage studies of MHS or CCD, two diseases characterized by a genetic heterogeneity.

Malignant hyperthermia susceptibility (MHS) is a subclinical pharmacogenetic disorder caused by an impairment of skeletal muscle calcium homeostasis in response to triggering agents. While in vitro contracture testing (IVCT) is the gold standard for defining MHS, molecular analysis is increasingly used to diagnosis MHS. Mutations associated with MHS have been reported in two genes: RYR1 and CACNA1S. Mutations in RYR1 are also responsible for central core disease (CCD), a myopathy that can be associated with a positive IVCT response. We report here the results of correlation studies performed with molecular, pharmacological, histological, and functional data obtained in 175 families (referred to as confirmed (129) or potential (46) MHS families). Extensive molecular analysis allowed us to identify a variant in 60% of the confirmed MHS families, and resulted in the characterization of 11 new variants in the RYR1 gene. Most mutations clustered to MH1 and MH2 domains of RYR1. Functional analysis allowed us to assign a causative role for seven MHS mutations that we propose to add to the panel of MHS mutations used for genetic testing. The use of genetic data to determine MHS status led to a 99.5% sensitivity for IVCT. IVCT-positive/mutation-negative diagnoses were analyzed not only in terms of specificity for IVCT, but also to assess the presence of a second MHS trait in families, and the genetic heterogeneity of the disease. Histological analyses revealed the presence of cores in more than 20% of muscle biopsies originating from 242 genotyped and tested MHS patients who did not present with clinical symptoms. This indicates that these patients must be considered as MHS patients with cores, and are clearly differentiated from CCD patients who have been tested positive for MHS.

This study aimed to explore the effect and mechanisms of rhein on sepsis-induced acute kidney injury by injecting lipopolysaccharide (LPS) and cecal ligation and puncture (CLP) in vivo, and on LPS-induced HK-2 cells in vitro. For histopathological analysis, rhein effectively attenuated the severity of renal injury. Rhein could significantly decrease concentration of BUN and SCr and level of TNF-α and IL-1β in two different mouse models of experimental sepsis. Moreover, rhein could markedly attenuate circulating leukocyte infiltration and enhance phagocytic activity of macrophages partly impaired at 12 h after CLP. Rhein could enhance cell viability and suppresse the release of MCP-1 and IL-8 in LPS-stimulated HK-2 cells Furthermore, rhein down regulated the expression of phosphorylated NF-κB p65, IκBα and IKKβ stimulated by LPS both in vivo and in vitro. All these results suggest that rhein has protective effects on endotoxin-induced kidney injury. The underlying mechanism of rhein on anti-endotoxin kidney injury may be closely related with its anti-inflammatory and immunomodulatory properties by decreasing NF-κB activation through restraining the expression and phosphorylation of the relevant proteins in NF-κB signal pathway, hindering transcription of NF-κB p65.These evidence suggest that rhein has a potential application to treat endotoxemia-associated acute kidney injury.

Graphitic carbon nitride has attracted extensive interests recently because of its potential in biosensing, photocatalytic, and biomedical applications. Similar to graphene, it is a two-dimensional carbon and nitrogen-based nanomaterial with weak van der Waals forces between each layer. Carbon nitrides can have various structural moieties such as triazine and heptazine. Unlike graphene-substituted nanosheets, the toxicity of graphitic carbon nitrite is largely unknown. In respond to that, toxicological study was carried out to determine its toxicity toward human lung carcinoma epithelial cells (A549). Two formazan-based cell viability assays (water-soluble tetrazolium salt (WST-8) assay and methylthiazolyldiphenyltetrazolium bromide (MTT) assay) were utilized on the A549 cell line to derive the cytotoxicity profile. Both materials demonstrated a dose-dependent toxicological effect with triazine-based carbon nitrides being more cytotoxic than heptazine-based carbon nitrides. These findings are of great importance, and this paves the way for exploring carbon nitride materials in numerous fields such as photocatalysis and electrocatalysis.