Quantifying the Nonclassicality of Operations

Deep insight can be gained into the nature of nonclassical correlations by studying the quantum operations that create them. Motivated by this we propose a measure of nonclassicality of a quantum operation utilizing the relative entropy to quantify its commutativity with the completely dephasing operation. We show that our measure of nonclassicality is a sum of two independent contributions, the generating power -- its ability to produce nonclassical states out of classical ones, and the distinguishing power -- its usefulness to a classical observer for distinguishing between classical and nonclassical states. Each of these effects can be exploited individually in quantum protocols. We further show that our measure leads to an interpretation of quantum discord as the difference in superdense coding capacities between a quantum state and the best classical state when both are produced at a source that makes a classical error during transmission.Comment: Published version, 5 pages, 3 figures plus 4 pages of Supplementary Materia

Transcriptomic profiling of TK2 deficient human skeletal muscle suggests a role for the p53 signalling pathway and identifies growth and differentiation factor-15 as a potential novel biomarker for mitochondrial myopathies

Background Mutations in the gene encoding thymidine kinase 2 (TK2) result in the myopathic form of mitochondrial DNA depletion syndrome which is a mitochondrial encephalomyopathy presenting in children. In order to unveil some of the mechanisms involved in this pathology and to identify potential biomarkers and therapeutic targets we have investigated the gene expression profile of human skeletal muscle deficient for TK2 using cDNA microarrays. Results We have analysed the whole transcriptome of skeletal muscle from patients with TK2 mutations and compared it to normal muscle and to muscle from patients with other mitochondrial myopathies. We have identified a set of over 700 genes which are differentially expressed in TK2 deficient muscle. Bioinformatics analysis reveals important changes in muscle metabolism, in particular, in glucose and glycogen utilisation, and activation of the starvation response which affects aminoacid and lipid metabolism. We have identified those transcriptional regulators which are likely to be responsible for the observed changes in gene expression. Conclusion Our data point towards the tumor suppressor p53 as the regulator at the centre of a network of genes which are responsible for a coordinated response to TK2 mutations which involves inflammation, activation of muscle cell death by apoptosis and induction of growth and differentiation factor 15 (GDF-15) in muscle and serum. We propose that GDF-15 may represent a potential novel biomarker for mitochondrial dysfunction although further studies are required

Functional outcome of children with mitochondrial diseases

We evaluated the functional outcome in a cohort of 22 children with mitochondrial diseases. The Pediatric Evaluation of Disability Inventory was administered and scaled scores determined. A large variability in functional skills was seen in all 3 assessed domains: Self-Care (46.4 \ub1 25.6 S.D.; median 42.4; range 11.8-100), Mobility (47.1 \ub1 30.4 S.D.; median 46.7; range 6.1-100), and Social Function (49.7 \ub1 22.3 S.D.; median 45.6; range 21.6-100). There was also a large variability in caregiver assistance, ranging from independent functioning to total dependence on assistance for the following: Self-Care (29.0 \ub1 33.7 S.D.; median 10.1; range 0-100), Mobility (36.6 \ub1 38.5 S.D.; median 26.1; range 0-100), and Social Function (42.9 \ub1 32.4 S.D.; median 44.4; range 0-100). The Pediatric Evaluation of Disability Inventory scores describe in depth different, but strongly related, aspects of everyday functioning in children with mitochondrial diseases. The importance of caregiver assistance in helping these children should not be underestimated. The use of assistive devices was estimated, which were found to be used by few patients. \ua9 2011 Elsevier Inc. All rights reserved

Abnormal expression of dysferlin in skeletal muscle and monocytes supports primary dysferlinopathy in patients with one mutated allele

Background: In some cases, a definitive confirmation of dysferlinopathy cannot be achieved by DNA test, because the mutation is detected in one allele only. Patients and methods: Dysferlin expression in skeletal muscle and peripheral blood monocytes (PBM) was studied by Western blot in two unrelated adult patients. The comparative CT method (ΔΔCT) was used to calculate relative changes in dysferlin mRNA determined from real-time quantitative PCR experiments. The dysferlin gene was studied by direct sequencing of cDNA and genomic DNA and by Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. Results: A comparable severe reduction in dysferlin was demonstrated in both skeletal muscle and PBM. The expression of dysferlin mRNA was significantly reduced. A novel mutation in exon 47 (c.5289G>C) of the dysferlin gene in the heterozygous state, causing an amino acid change (p.Glu1763Asp), was detected in both patients. The MLPA analysis did not reveal any deletion or duplication. Conclusions: Dysferlin and/or dysferlin mRNA abnormalities are diagnostic for dysferlinopathy when mutational analysis detects a mutation in one allele only. Analysis of dysferlin mRNA can be helpful for distinguishing symptomatic heterozygotes from such patients. © 2010 The Author(s). European Journal of Neurology © 2010 EFNS