A computational approach to identify point mutations associated with occult hepatitis B: significant mutations affect coding regions but not regulative elements of HBV

<p>Abstract</p> <p>Background</p> <p>Occult Hepatitis B Infection (OBI) is characterized by absence of serum HBsAg and persistence of HBV-DNA in liver tissue, with low to undetectable serum HBV-DNA. The mechanisms underlying OBI remain to be clarified. To evaluate if specific point mutations of HBV genome may be associated with OBI, we applied an approach based on bioinformatics analysis of complete genome HBV sequences. In addition, the feasibility of bioinformatics prediction models to classify HBV infections into OBI and non-OBI by molecular data was evaluated.</p> <p>Methods</p> <p>41 OBI and 162 non-OBI complete genome sequences were retrieved from GenBank, aligned and subjected to univariable analysis including statistical evaluation. Their S coding region was analyzed for Stop codon mutations too, while S amino acid variability could be evaluated for genotype D only, due to the too small number of available complete genome OBI sequences from other genotypes.</p> <p>Prediction models were derived by multivariable analysis using Logistic Regression, Rule Induction and Random Forest approaches, with extra-sample error estimation by Multiple ten-fold Cross-Validation (MCV). Models were compared by t-test on the Area Under the Receiver Operating Characteristic curve (AUC) distributions obtained from the MCV runs for each model against the best-performing model.</p> <p>Results</p> <p>Variations in seven nucleotide positions were significantly associated with OBI, and occurred in 11 out of 41 OBI sequences (26.8%): likely, other mutations did not reach statistical significance due to the small size of OBI dataset. All variations affected at least one HBV coding region, but none of them mapped to regulative elements. All viral proteins, with the only exception of the X, were affected. Stop codons in the S, that might account for absence of serum HBsAg, were not significantly enriched in OBI sequences. In genotype D, amino acid variability in the S was higher in OBI than non-OBI, particularly in the immunodominant region. A Random Forest prediction model showed the best performance, but all models were not satisfactory in terms of specificity, due to the small sample size of OBIs; however results are promising in the perspective of a broader dataset of complete genome OBI sequences.</p> <p>Conclusions</p> <p>Data suggest that point mutations rarely occur in regulative elements of HBV, if ever, and contribute to OBI by affecting different viral proteins, suggesting heterogeneous mechanisms may be responsible for OBI, including, at least in genotype D, an escape mutation mechanism due to imperfect immune control. It appears possible to derive prediction models based on molecular data when a larger set of complete genome OBI sequences will become available.</p

Low-molecular-weight heparins induce decidual heparin-binding epidermal growth factor–like growth factor expression and promote survival of decidual cells undergoing apoptosis Nicoletta Di

Objective: To evaluate the effects of low-molecular-weight heparins (LMWHs) on decidual heparin-binding epidermal growth factor–like growth factor (HB-EGF) expression/secretion and on TNF-a–induced decidual apoptosis. Design: Experimental study. Setting: Department of Obstetrics and Gynecology, Universita Cattolica del Sacro Cuore, Rome, Italy. Patient(s): Cultures of primary decidual cells isolated from human term placenta. Intervention(s): The effects of LMWHs (tinzaparin and enoxaparin) on decidual HB-EGF expression and secretion were investigated by Western blot analysis and ELISA, respectively. TNF-a–induced decidual apoptosis was evaluated by annexin V staining, terminal deoxynucleotide transferase– mediated dUTP nick-end labeling (TUNEL) assay, and caspase activities. Main Outcome Measure(s): Decidual HB-EGF expression/secretion and apoptotic rate induced by TNF-a were investigated. Result(s): Tinzaparin enhanced decidual HB-EGF expression and secretion. TNF-a reduced the number of viable cells by inducing apoptosis. Simultaneous addition of LMWHs (primarily tinzaparin) blocked the increase in annexin V– and TUNEL-positive cells and reduced the amount of caspase activities. Conclusion(s): Both LMWHs induced a significant increase in decidual HB-EGF expression/secretion and reduced TNF-a–induced decidual apoptosis. Tinzaparin demonstrated higher efficacy. (Fertil Steril 2012;97:169–77. 2012 by American Society for Reproductiv

Normal and cancer-prone human cells respond differently to extremely low frequency magnetic fields. FEBS Lett 487:397–403

Abstract Human lymphoblastoid cells of normal origin and from genetic instability syndromes, i.e. Fanconi anemia (FA) group C and ataxia telangectasia, were continuously exposed to extremely low frequency magnetic field (ELF-MF). We report that ELF-MF, though not perturbing cell cycle progression, increases the rate of cell death in normal cell lines. In contrast, cell death is not affected in cells from genetic instability syndromes; this reflects a specific failure of the apoptotic response. Reintroduction of complementation group C in FA cells re-established the apoptotic response to ELF-MF. Thus, genes implicated in genetic instability syndromes are relevant in modulating the response of cells to ELF-MF.

Are endothelial progenitor cells mobilized by myocardial ischemia or myocardial necrosis? A cardiac magnetic resonance study

Background: In ST-elevation myocardial infarction (STEMI) patients, the main stimuli involved in endothelial progenitor cells (EPCs) mobilization are not fully understood. We aimed to assess by cardiac magnetic resonance (CMR) whether the extent of ischemic myocardium (area at risk (AAR)) or of necrotic myocardium (infarct size (IS)) can be correlated to levels of circulating EPCs

Pleiotropic Beneficial Effects of Sonic Hedgehog Gene Therapy in an Experimental Model of Peripheral Limb Ischemia

We have previously shown that the signaling pathway of the embryonic morphogen Sonic hedgehog (Shh) is recapitulated in the postnatal skeletal muscle in response to ischemia. We have also demonstrated that Shh is an indirect angiogenic agent upregulating various families of angiogenic growth factors and that Shh gene therapy improves angiogenesis and heart function in experimental models of myocardial ischemia. Based on these findings, we hypothesized that Shh gene therapy is beneficial in an experimental model of peripheral ischemia. We found that intramuscular (i.m.) treatment with a plasmid encoding the Shh human gene (phShh) increased blood flow, capillary density, and arteriole density in mice in which peripheral circulation of the hindlimb was disrupted by removal of the common femoral artery. Shh gene therapy also enhanced vasculogenesis, by increasing the number of circulating bone marrow (BM)-derived endothelial precursors and improving the contribution of these cells to the process of neovascularization. Finally, phShh treatment induced upregulation of prototypical angiogenic, arteriogenic, and vasculogenic factors, such as vascular endothelial growth factor (VEGF), angiopoietin 1 (Ang-1), and stromal cell-derived factor-1 (SDF-1α). These data suggest that Shh gene therapy merits further investigation for its ability to trigger the expression of potent trophic factors and stimulate pleiotropic aspects of neovascularization in the setting of ischemia