West Nile Virus Seroprevalence in the Greek Population in 2013: A Nationwide Cross-Sectional Survey

Cases of West Nile Virus (WNV) disease were recorded for three consecutive years in Greece following the year 2010 outbreak. A cross-sectional serologic survey was conducted to estimate the WNV seroprevalence and assess the ratio of infection to neuroinvasive disease. A stratified left-over sampling methodology was used including age and residence strata. A total of 3,962 serum samples was collected and tested for WNV Immunoglobulin G (IgG) antibodies by Enzyme–Linked Immunosorbent Assay (ELISA). All positive samples were further tested by Plaque Reduction Neutralization Test (PRNT) and WNV Immunoglobulin M (IgM) antibodies. WNV IgG antibodies were detected in 82 samples and 61 were also positive in PRNT representing a weighted seroprevalence of 2.1% (95% C.I.: 1.7–2.6) and 1.5% (95% C.I.: 1.2–2.0), respectively. Multivariable analysis showed that seroprevalence was associated with age and residence. The overall ratio of neuroinvasive disease to infected persons was estimated at 1:376 (95% C.I.: 1:421–1:338), while the elderly people had the highest ratio. This nationwide study provided valuable data regarding the epidemiology of WNV in Greece based on the fact that elderly people have higher risk of being both infected and having severe disease.     

Circulating Carnosine Dipeptidase 1 Associates with Weight Loss and Poor Prognosis in Gastrointestinal Cancer

Background

Cancer cachexia (CC) is linked to poor prognosis. Although the mechanisms promoting this condition are not known, several circulating proteins have been proposed to contribute. We analyzed the plasma proteome in cancer subjects in order to identify factors associated with cachexia.

Design/Subjects

Plasma was obtained from a screening cohort of 59 patients, newly diagnosed with suspected gastrointestinal cancer, with (n = 32) or without (n = 27) cachexia. Samples were subjected to proteomic profiling using 760 antibodies (targeting 698 individual proteins) from the Human Protein Atlas project. The main findings were validated in a cohort of 93 patients with verified and advanced pancreas cancer.

Results

Only six proteins displayed differential plasma levels in the screening cohort. Among these, Carnosine Dipeptidase 1 (CNDP1) was confirmed by sandwich immunoassay to be lower in CC (p = 0.008). In both cohorts, low CNDP1 levels were associated with markers of poor prognosis including weight loss, malnutrition, lipid breakdown, low circulating albumin/IGF1 levels and poor quality of life. Eleven of the subjects in the discovery cohort were finally diagnosed with non-malignant disease but omitting these subjects from the analyses did not have any major influence on the results.

Conclusions

In gastrointestinal cancer, reduced plasma levels of CNDP1 associate with signs of catabolism and poor outcome. These results, together with recently published data demonstrating lower circulating CNDP1 in subjects with glioblastoma and metastatic prostate cancer, suggest that CNDP1 may constitute a marker of aggressive cancer and CC.     

Self-assembly of proximity probes for flexible and modular proximity ligation assays

Proximity ligation assay (PLA) is a recently developed strategy for protein analysis in which antibody-based detection of a target protein via a DNA ligation reaction of oligonucleotides linked to the antibodies results in the formation of an amplifiable DNA strand suitable for analysis. Here we describe a faster and more cost-effective strategy to construct the antibody-based proximity ligation probes used in PLA that is based on the noncovalent interaction of biotinylated oligonucleotides with streptavidin followed by the interaction of this complex with biotinylated antibodies.     

FR258900, a potential anti-hyperglycemic drug, binds at the allosteric site of glycogen phosphorylase

FR258900 has been discovered as a novel inhibitor of human liver glycogen phosphorylase a and proved to suppress hepatic glycogen breakdown and reduce plasma glucose concentrations in diabetic mice models. To elucidate the mechanism of inhibition, we have determined the crystal structure of the cocrystallized rabbit muscle glycogen phosphorylase b-FR258900 complex and refined it to 2.2 A resolution. The structure demonstrates that the inhibitor binds at the allosteric activator site, where the physiological activator AMP binds. The contacts from FR258900 to glycogen phosphorylase are dominated by nonpolar van der Waals interactions with Gln71, Gln72, Phe196, and Val45' (from the symmetry-related subunit), and also by ionic interactions from the carboxylate groups to the three arginine residues (Arg242, Arg309, and Arg310) that form the allosteric phosphate-recognition subsite. The binding of FR258900 to the protein promotes conformational changes that stabilize an inactive T-state quaternary conformation of the enzyme. The ligand-binding mode is different from those of the potent phenoxy-phthalate and acyl urea inhibitors, previously described, illustrating the broad specificity of the allosteric site.     

Scabies epidemiology in health care centers for refugees and asylum seekers in Greece

BackgroundScabies is a global health concern disproportionately affecting vulnerable populations such as refugees and asylum seekers. Greece is a main point of entry in Europe for refugees, but epidemiological data on scabies in this population are scarce. We aimed to describe the epidemiology of scabies, including trends over the study period.Methodology/Principal findingsData were collected from June, 2016 to July, 2020, using the surveillance system of the Greek National Public Health Organization. Daily reports on scabies and other infectious diseases were submitted by staff at health centers for refugees/asylum seekers. Observed proportional morbidity for scabies was calculated using consultations for scabies as a proportion of total consultations.There were a total of 13118 scabies cases over the study period. Scabies was the third most frequently observed infectious disease in refugees/asylum seekers population after respiratory infections and gastroenteritis without blood in the stool. The scabies monthly observed proportional morbidity varied between 0.3% (August 2017) to 5.7% (January 2020). Several outbreaks were documented during the study period. The number of cases increased from October 2019 until the end of the study period, with a peak of 1663 cases in January 2020, related to an outbreak at one center. Spearman correlation test between the number of reported scabies cases and time confirmed an increasing trend (ρ = 0.67).Conclusions/SignificanceScabies is one of the most frequently reported infectious diseases by health care workers in refugee/asylum seekers centers in Greece. Observed proportional morbidity for scabies increased over time and there were several outbreaks. The current surveillance system with daily reports of the new cases effectively detects new cases in an early stage. Public health interventions, including mass drug administration, should be considered to reduce the burden of scabies in refugee/migrant populations.     

Notch signalling in vertebrate neural development

Signals through the Notch receptors are used throughout development to control cellular fate choices. Loss- and gain-of-function studies revealed both the pleiotropic action of the Notch signalling pathway in development and the potential of Notch signals as tools to influence the developmental path of undifferentiated cells. As we review here, Notch signalling affects the development of the nervous system at many different levels. Understanding the complex genetic circuitry that allows Notch signals to affect specific cell fates in a context-specific manner defines the next challenge, especially as such an understanding might have important implications for regenerative medicine.     

Regulation of Ang2 release by PTEN/PI3-kinase/Akt in lung microvascular endothelial cells

Angiopoietin-2 (Ang2) is a Tie-2 ligand that destabilizes vascular structures, allowing for neovascularization or vessel regression depending on local vascular endothelial cell growth factor (VEGF) concentrations. Although various stimuli have been shown to affect Ang2 expression, information on the underlying mechanisms involved in Ang2 production in endothelial cells (EC) is just beginning to emerge. In the present study, we have used adenovirus-mediated gene transfer and pharmacological inhibitors to examine the role of the PTEN/PI3-K/Akt pathway on Ang2 release. Inhibition of PI3-kinase with wortmannin led to a stimulation of basal Ang2 release in EC, while overexpression of an active form of Akt reduced Ang2. In addition, adenovirus-mediated gene transfer of the phosphatase PTEN stimulated Ang2 release. Incubation of the cells with Ang1, an agent that activates the PI3-K/Akt pathway in EC, reduced Ang2 release. This effect of Ang1 could be prevented by wortmannin and LY-294002 pretreatment. Similarly, in VEGF-treated EC the increase in Ang2 production observed was greater in the presence of a PI3-K inhibitor. Our observations that PTEN acts as a positive modulator of Ang2 release, while activation of the PI3-K/Akt pathway downregulates Ang2, reveal an additional mechanism through which the PTEN/PI3-K/Akt pathway could affect the angiogenic process.     

Enneanuclear Ni(II) complexes from the use of the flexible ligand 2-pyridinealdoxime: The nature of the inorganic anion does not affect the chemical and structural identity of the cationic cluster

The use of 2-pyridinealdoximate(−1) [(py)CHNO⁻] in nickel(II) chemistry has been further investigated. The synthetic investigation has led to two new salts of the very recently reported (in the form of its tetraperchlorate salt, 1) enneanuclear cation [Ni₉(μ₃-OH)₂(μ₂-OH)₂{μ₃-(py)CHNO}₄{μ₂-(py)CHNO}₆(μ₂-OH₂)₂(H₂O)₆]⁴⁺. The two new cationic clusters [Ni₉(OH)₄{(py)CHNO}₁₀(H₂O)₈](SCN)₂(OH)₂ · 9.91H₂O (2 · 9.91H₂O) and [Ni₉(OH)₄{(py)CHNO}₁₀(H₂O)₈]{N(CN)₂}₃(ClO₄) · 11.11H₂O (3 · 11.11H₂O) have been structurally characterized by single-crystal X-ray crystallography at 100 K. The nature of the inorganic anions (Cl⁻/SCN⁻,) present in the reaction mixtures does not affect the chemical and structural identity of the enneanuclear cation. Characteristic IR data are discussed in terms of the nature of bonding and the structures of the complexes. The variable-temperature magnetic susceptibility data of 1, which had also been obtained by our group, were simulated by means of a 3-J model, which is compared with the 2-J model reported for this cluster by Chaudhuri and co-workers [S. Khanra, T. Weyhermüller, E. Rentschler, P. Chaudhuri, Inorg. Chem. 44 (2005) 8176]. The ground-state total spin of the cluster is S_T = 1.     

Novel function of the human presqualene diphosphate phosphatase as a type II phosphatidate phosphatase in phosphatidylcholine and triacylglyceride biosynthesis pathways

Phosphatidate phosphatases, PAPs, are key enzymes in lipid biosynthesis and signaling. Type I PAP enzymes participate in de-novo phospholipid biosynthesis, whereas type II PAP enzymes have an established role in lipid signaling. To identify novel human type II PAPs potentially involved in de-novo phospholipid synthesis we used bioinformatics to screen for enzymes with an active site exposed to the cytosolic side of membranes. Two related enzymes, a novel lipid phosphatase related protein (LPRP-A) and a presqualene diphosphate phosphatase (PA-PSP) met this criterion. PA-PSP and LPRP-A have differential tissue and subcellular distribution, and novel yet differential roles in lipid metabolism. Specifically, PA-PSP, but not LPRP-A, was a potent Mg(2+)-independent, NEM-insensitive type II PAP. Subcellular fractionation detection indicated that both proteins were associated with membranes, while immunofluorescent deconvolution imaging revealed that these membranes were exclusively from the nuclear envelope and the endoplasmic reticulum. PA-PSP overexpression, but not LPRP-A, accelerated the synthesis of phosphatidylcholine and caused accumulation of triacylglycerol with concomitant decrease in the rate of phosphatidylinositol synthesis. Coexpression of human CTP:phosphocholine cytidylyltransferase-alpha with PA-PSP enhanced the effect of PA-PSP on phosphatidylcholine levels, yet attenuated its effect on triacylglycerol. Taken together, our studies provide the first evidence that the eukaryotic, ER-resident PA-PSP is a bifunctional enzyme with specific type II PAP activity, and regulates, in addition to type I PAPs, the de-novo biosynthesis of phospholipids and triacylglycerols.