Hepatitis C virus NS2 protein inhibits gene expression from different cellular and viral promoters in hepatic and nonhepatic cell lines

The mechanisms leading to viral persistence and hepatocarcinogenesis in hepatitis C virus (HCV) infection are not fully understood. Recently, evidence has been accumulated that HCV viral proteins might interfere with gene expression of host cells. Here, we demonstrate that the amino-terminal portion of HCV NS2 protein inhibits the expression of reporter genes driven by different promoters or enhancer elements and also inhibits hepatitis B virus (HBV) gene expression and HBV DNA replication. The inhibitory effect of HCV NS2 on liver and non-liver-specific promoters and enhancer elements might be relevant for the pathogenesis of chronic HCV infection.     

Minimally Invasive Retroperitoneal Approach for Pancreatic Necrosectomy via a Percutaneous Drainage Tract

Aim-Background

Infected pancreatic necrosis (IPN) develops in approximately one third of patients with necrotizing pancreatitis (NP). In the past, open necrosectomy (ON) was the standard treatment for this condition, but it carried significant morbidity and mortality. Currently, minimally invasive procedures (MIPs) have been established for the management of IPN, decreasing the risk of complications compared with ON.

Methods

A prospective study was made of patients with IPN treated by a MIP for necrosectomy via a percutaneous drainage catheter, followed by video-assisted retroperitoneal debridement (VARD).

Results

Between 2013 and 2016, 3 consecutive patients, with a mean age of 58 years, underwent a MIP for the management of IPN. All 3 patients had left lateral retroperitoneal pockets of necrosis, and the first-line procedure consisted of placement of a pigtail catheter. The drain tract was subsequently used to carry out VARD. None of the patients presented major postoperative complications or required re-intervention.

Conclusion

The management of IPN has shifted away from ON, which was associated with high morbidity, towards less invasive techniques. MIPs should be used initially as the surgical treatment of choice in most cases. When this is not feasible, or when the MIP is not successful, ON should be implemented.

     

Antibodies to hepatitis E virus among several populations in Greece: increased prevalence in an hemodialysis unit

BACKGROUND: Hepatitis E virus (HEV) has been found to be the causative agent of enterically transmitted non-A, non-B hepatitis in tropical and subtropical countries. Several investigators, however, have indicated that HEV could be endemic in Europe, albeit at a low prevalence. STUDY DESIGN AND METHODS: The purpose of this study was to estimate the prevalence of anti-HEV in various populations in northwestern Greece (Epirus region). Healthy blood donors (2636), refugees from southern Albania (350), children (165), injecting drug users (IDUs) (65), multiply transfused patients (62), patients with chronic viral hepatitis (75), and chronic hemodialysis patients (149) were investigated for anti-HEV by enzyme immunoassay and confirmatory Western blot assay. In addition, 380 consecutive healthy blood donors and 62 hemodialysis patients from a neighboring area (Agrinion, Greece) were investigated. RESULTS: A very low presence of anti-HEV antibody was found among healthy blood donors from Epirus (0.23%) and Agrinion (0.53%). Anti-HEV was not detected in children, IDUs, or multiply transfused patients. In contrast, a low but significant prevalence of anti-HEV was found among refugees (4.85%), patients with chronic viral hepatitis (5.3%), and hemodialysis patients from Epirus (1.34%), as compared with healthy blood donors from Epirus: p < 0.0001, p < 0.00001, and p < 0.10, respectively. A high prevalence (9.7%) of anti- HEV was revealed in patients at the hemodialysis unit of the General Hospital of Agrinion (p < 0.00005, compared to healthy blood donors from Agrinion). No significant association was found between anti-HEV positivity and the age or sex of donors, the duration of hemodialysis, positivity for hepatitis B or C virus infection markers, history of hepatitis, increased alanine aminotransferase, renal transplantation, a history of transfusion, or the number of units transfused. CONCLUSION: This study demonstrated a high prevalence of anti-HEV in a separate hemodialysis unit, without an association with the known routes of transmission of blood-borne viruses. This observation suggests that a still-undefined intra-unit factor or other factors are associated with HEV transmission.     

Nanomechanical mechanism for lipid bilayer damage induced by carbon nanotubes confined in intracellular vesicles

Understanding the behavior of low-dimensional nanomaterials confined in intracellular vesicles has been limited by the resolution of bioimaging techniques and the complex nature of the problem. Recent studies report that long, stiff carbon nanotubes are more cytotoxic than flexible varieties, but the mechanistic link between stiffness and cytotoxicity is not understood. Here we combine analytical modeling, molecular dynamics simulations, and in vitro intracellular imaging methods to reveal 1D carbon nanotube behavior within intracellular vesicles. We show that stiff nanotubes beyond a critical length are compressed by lysosomal membranes causing persistent tip contact with the inner membrane leaflet, leading to lipid extraction, lysosomal permeabilization, release of cathepsin B (a lysosomal protease) into the cytoplasm, and cell death. The precise material parameters needed to activate this unique mechanical pathway of nanomaterials interaction with intracellular vesicles were identified through coupled modeling, simulation, and experimental studies on carbon nanomaterials with wide variation in size, shape, and stiffness, leading to a generalized classification diagram for 1D nanocarbons that distinguishes pathogenic from biocompatible varieties based on a nanomechanical buckling criterion. For a wide variety of other 1D material classes (metal, oxide, polymer), this generalized classification diagram shows a critical threshold in length/width space that represents a transition from biologically soft to stiff, and thus identifies the important subset of all 1D materials with the potential to induce lysosomal permeability by the nanomechanical mechanism under investigation.The interactions of low-dimensional materials with the external or plasma membrane of living cells have been the subject of prior studies due to their importance in uptake and delivery, antibacterial action, and nanomaterial safety (1–6). Following uptake, nanomaterials may also interact with internal membranes while under confinement in intracellular vesicles (7–10), but the biophysics of these geometrically constrained systems is poorly understood. Low-dimensional materials interact with biological systems in complex ways dictated by their 1D nanofibrous or 2D nanosheet geometries (7, 11–20). These interactions typically begin when materials encounter the plasma membrane and initiate phenomena that can include adhesion, membrane deformation, penetration, lipid extraction, entry, frustrated uptake, or cytotoxicity (4, 11–14, 19–21). Recent experimental data suggest that the cellular response to some 1D materials is governed by their interaction with the internal lipid-bilayer membranes of endosomes and lysosomes following nanomaterial uptake (7–10). The resulting geometry is fundamentally different in that the fibrous materials are confined within a vesicle, imposing geometric constraints and introducing mechanical forces that act bidirectionally––i.e., on both the thin fibrous structure and the inner leaflet of the soft membrane. The fundamental biophysics of this tube-in-vesicle system is virtually unexplored, yet may be critical for understanding the cellular response to nanotubes/fibers, where shape and stiffness are among the known determinants of toxicity (13, 21). The technique of coarse-grained molecular dynamics (MD), demonstrated to be effective in the study of complex biomolecular systems (22, 23), has been applied to whole lipid-bilayer patches to reveal a biophysical mechanism for carbon nanotube interaction with the plasma membranes leading to tip entry and uptake (4, 19, 20). The same technique may also provide insight relevant to internal membrane interactions, although whole vesicle MD is a significant challenge. Here we use a complement of techniques including coarse-grained MD, all-atom MD, in vitro bioimaging, and carbon nanotube length modification to reveal the behavior of vesicle-encapsulated carbon nanotubes and identify the conditions and carbon nanotube (CNT) types that lead to mechanical stress and membrane damage following cellular uptake and packaging in lysosomes (8).     

CERAD-NP-Testbatterie: Alters-, geschlechts- und bildungsspezifische Normen ausgew?hlter Subtests

The CERAD-NP battery represents well-established tests for the neuropsychological diagnosis of characteristic cognitive deficits in Alzheimer’s dementia. However, the use of neuropsychological tests requires reliable standard values for the population under consideration, taking sociodemographic characteristics like age, education and gender into account. This report presents age-, education- and gender-specific reference values for the subtests verbal fluency, word list memory, word list recall and word list recognition as well as the word list savings score of the CERAD-NP battery. The study sample consists of 2891 general practitioners’ patients from Germany aged 75 years and older. The study participants had a mean age of 80.2 years (SD=3.6); thus, this report provides reliable reference values for the neuropsychological diagnosis of dementia in older age groups.     

Posttranslational processing and targeting of transgenic human defensin in murine granulocyte, macrophage, fibroblast, and pituitary adenoma cell lines

Human defensins are 29 to 30 amino acid (aa) antimicrobial peptides that are among the principal constituents of the neutrophil's azurophil granules. To determine the tissue specificity of posttranslational processing and subcellular targeting of defensins, the cDNA for a 94 aa human preprodefensin was transduced into murine cell lines (NIH 3T3 embryonic fibroblasts, AtT-20 pituitary adenoma, J774.1 and RAW 264.7 macrophages, and 32D and 32D cl3 granulocytes) using retroviral vectors. All transduced cell types expressed and to a variable extent constitutively secreted a 75 aa prodefensin formed by the removal of the amino terminal signal sequence. In AtT-20 cells, the 75 aa form accumulated intracellularly in granules and was releasable by secretagogues. Proteolytic processing to mature defensins was seen only in myeloid cells (J774.1, RAW 264.7, 32D, and 32D cl3). Newly formed mature defensin was rapidly degraded in J774.1 and RAW 264.7 macrophages, but accumulated stably in multivesicular bodies in 32D cells and in cytoplasmic granules of 32D cl3 cells. Our data suggest that the enzymatic and transport machinery required to process preprodefensin to mature defensin and to store it in cytoplasmic granules is a specialized feature of cells of granulocytic lineage.