Kappa-deformed random-matrix theory based on Kaniadakis statistics

We present a possible extension of the random-matrix theory, which is widely used to describe spectral fluctuations of chaotic systems. By considering the Kaniadakis non-Gaussian statistics, characterized by the index {\kappa} (Boltzmann-Gibbs entropy is recovered in the limit {\kappa}\rightarrow0), we propose the non-Gaussian deformations ({\kappa} \neq 0) of the conventional orthogonal and unitary ensembles of random matrices. The joint eigenvalue distributions for the {\kappa}-deformed ensembles are derived by applying the principle maximum entropy to Kaniadakis entropy. The resulting distribution functions are base invarient as they depend on the matrix elements in a trace form. Using these expressions, we introduce a new generalized form of the Wigner surmise valid for nearly-chaotic mixed systems, where a basis-independent description is still expected to hold. We motivate the necessity of such generalization by the need to describe the transition of the spacing distribution from chaos to order, at least in the initial stage. We show several examples about the use of the generalized Wigner surmise to the analysis of the results of a number of previous experiments and numerical experiments. Our results suggest the entropic index {\kappa} as a measure for deviation from the state of chaos. We also introduce a {\kappa}-deformed Porter-Thomas distribution of transition intensities, which fits the experimental data for mixed systems better than the commonly-used gamma-distribution.Comment: 18 pages, 8 figure

Meeting report: discussions and preliminary findings on extracellular RNA measurement methods from laboratories in the NIH Extracellular RNA Communication Consortium

Extracellular RNAs (exRNAs) have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA-containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in-person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field

Metallothionein expression correlates with metastatic and proliferative potential in squamous cell carcinoma of the oesophagus

The goal of this study is to clarify whether the expression of metallothionein (MT) could affect the prognosis and the metastatic potential of squamous cell carcinoma (SCC) of the oesophagus. In paraffin-embedded specimens resected from 57 patients, MT mRNA and protein expressions were detected by in situ hybridization and immunohistochemistry respectively. The expression of MT was evaluated in respect of clinicopathologic variables and patients' survival. MT mRNA expression was significantly associated with the proportion of lymph node metastasis (71% in MT mRNA-positive tumours vs 42% in MT mRNA-negative tumours; P = 0.0343) and that of distant metastasis (29% in MT mRNA-positive tumours vs 5% in MT mRNA-negative tumours; P = 0.0452). In respect of MT protein expression, the frequency of distant metastasis was more common in MT-positive tumours than in MT-negative tumours (30% in MT-positive tumours vs 8% in MT-negative tumours; P = 0.0446). The survival rate of the patients with MT protein-negative tumours was significantly better than that of the patients with MT protein-positive tumours (P = 0.0340). There was a positive correlation between the expression of MT protein and that of proliferating cell nuclear antigen (P = 0.0018). Therefore, we conclude that MT expression, both at the mRNA and protein levels, may be a potential marker predicting metastatic and proliferative activities of oesophageal SCC. © 1999 Cancer Research Campaig

Novel role for the transient receptor potential channel TRPM2 in prostate cancer cell proliferation

We have identified a novel function for a member of the transient receptor potential (TRP) protein super-family, TRPM2, in prostate cancer cell proliferation. TRPM2 encodes a non-selective cation-permeable ion channel. We found that selectively knocking down TRPM2 with the small interfering RNA technique inhibited the growth of prostate cancer cells but not of non-cancerous cells. The subcellular localization of this protein is also remarkably different between cancerous and non-cancerous cells. In BPH-1 (benign), TRPM2 protein is homogenously located near the plasma membrane and in the cytoplasm, whereas in the cancerous cells (PC-3 and DU-145), a significant amount of the TRPM2 protein is located in the nuclei in a clustered pattern. Furthermore, we have found that TRPM2 inhibited nuclear ADP-ribosylation in prostate cancer cells. However, TRPM2 knockdown-induced inhibition of proliferation is independent of the activity of poly(ADP-ribose) polymerases. We conclude that TRPM2 is essential for prostate cancer cell proliferation and may be a potential target for the selective treatment of prostate cancer

Potential role of p53 on metallothionein induction in human epithelial breast cancer cells

The expression and induction of metallothionein has been associated with protection against oxidative stress and apoptosis. This study examines the effect of tumour suppressor protein p53 on metallothionein expression following CdCl2 treatment in eight human epithelial breast cancer cell lines differing in p53 and oestrogen-receptor status. Cells were treated with 10 μM CdCl2 for 24 h and metallothionein protein levels were measured by cadmium binding assay. MCF7 cells which are p53-positive (p53+) and oestrogen-receptor-positive showed a large induction in metallothionein synthesis by 10.79±1.36-fold. Other breast cancer cell lines which are p53-negative (p53−) and oestrogen-receptor-negative or weakly oestrogen-receptor-positive showed a small induction ranging from 1.40±0.10 to 3.65±0.30-fold. RT–PCR analysis showed an induction of metallothionein mRNA in MCF7 cells by about 1.61±0.08-fold, while in HCC1806 cells (p53−, oestrogen-receptor-negative) by 1.11±0.13-fold, and in MDA-MB-231 (p53−, oestrogen-receptor-negative) by 1.25±0.06-fold. Metallothionein localisation was determined by immunohistochemical staining. Prior to metal treatment, metallothionein was localised mainly in the cytoplasm of MCF7 and MDA-MB-231 cells. After treatment with 10 μM CdCl2 for 24 h, MCF7 cells showed intense nuclear and cytoplasmic staining for metallothionein, while MDA-MB-231 cells showed staining in the cytoplasm with weak nuclear staining. Apoptosis induced by 10–40 μM CdCl2 at time points between 4 and 48 h was examined with TUNEL assay. In MCF7 cells, apoptosis increased with higher concentrations of CdCl2, it peaked at 6–8 h and appeared again at 48 h for all concentrations of CdCl2 tested. In MDA-MB-231 cells, apoptosis remained at low levels for 10–40 μM CdCl2 at all time points. Studies on cadmium uptake showed similar uptake and accumulation of cadmium at 8 and 24 h in all the cell lines. The data demonstrate that treatment of epithelial breast cancer cells with 10 μM CdCl2 for 24 h caused a greater induction of metallothionein protein and mRNA expression in p53+ and oestrogen-receptor-positive cells as compared to p53− and oestrogen-receptor-negative or weakly oestrogen-receptor-positive cells. This effect may be associated with the occurrence of apoptosis and suggests a role for p53 and oestrogen-receptor on the expression and induction of metallothionein in epithelial cells

Evolution of the avian β-defensin and cathelicidin genes

Background: β-defensins and cathelicidins are two families of cationic antimicrobial peptides (AMPs) with a broad range of antimicrobial activities that are key components of the innate immune system. Due to their important roles in host defense against rapidly evolving pathogens, the two gene families provide an ideal system for studying adaptive gene evolution. In this study we performed phylogenetic and selection analyses on β-defensins and cathelicidins from 53 avian species representing 32 orders to examine the evolutionary dynamics of these peptides in birds. Results and conclusions: Avian β-defensins are found in a gene cluster consisting of 13 subfamiles. Nine of these are conserved as one to one orthologs in all birds, while the others (AvBD1, AvBD3, AvBD7 and AvBD14) are more subject to gene duplication or pseudogenisation events in specific avian lineages. Avian cathelicidins are found in a gene cluster consisting of three subfamilies with species-specific duplications and gene loss. Evidence suggested that the propiece and mature peptide domains of avian cathelicidins are possibly co-evolving in such a way that the cationicity of the mature peptide is partially neutralised by the negative charge of the propiece prior to peptide secretion (further evidence obtained by repeating the analyses on primate cathelicidins). Negative selection (overall mean d

Meeting report: discussions and preliminary findings on extracellular RNA measurement methods from laboratories in the NIH Extracellular RNA Communication Consortium

Extracellular RNAs (exRNAs) have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA-containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in-person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field