Two cases of primary splenic hydatid cyst in Greece

Cystic disease of the spleen is an uncommon entity in general population. Most cases result from parasitic infection by Echinococcus granulosus, a form called splenic hydatid disease (SHD), with a reported frequency of 0.5-6.0% within abdominal hydatidosis. On the contrary, an isolated splenic involvement of hydatid disease is very uncommon even in endemic regions. Two cases of primary SHD managed with open and laparoscopic radical surgery in our department are reported herein. Primary SHD is a rare entity with non-specific symptoms underlying clinical suspicion by the physician for prompt diagnosis. Surgical treatment is the mainstay therapy, while laparoscopic approach when feasible is safe, offering the advantages of laparoscopic surgery.     

C-Glucosylated malonitrile as a key intermediate towards carbohydrate-based glycogen phosphorylase inhibitors

Glycogen utilization involves glycogen phosphorylase, an enzyme which appears to be a potential target for the regulation of glycaemia, as the liver isoform is a major player for hepatic glucose output. A single C-glucosylated malonitrile allowed for the synthesis of three glucose-based derivatives namely bis-oxadiazoles, bis-amides and a C-glucosylated tetrahydropyrimidin-2-one. When evaluated as glycogen phosphorylase inhibitors, two of the synthesized compounds displayed inhibition in the sub-millimolar range. In silico studies revealed that only one out of the bis-amides obtained and the C-glucosylated tetrahydropyrimidin-2-one may bind at the catalytic site.     

Triazole pyrimidine nucleosides as inhibitors of Ribonuclease A. Synthesis,biochemical, and structural evaluation

Five ribofuranosyl pyrimidine nucleosides and their corresponding 1,2,3-triazole derivatives have been synthesized and characterized. Their inhibitory action to Ribonuclease A has been studied by biochemical analysis and X-ray crystallography. These compounds are potent competitive inhibitors of RNase A with low μM inhibition constant (K_i) values with the ones having a triazolo linker being more potent than the ones without. The most potent of these is 1-[(β-d-ribofuranosyl)-1,2,3-triazol-4-yl]uracil being with K_i = 1.6 μM. The high resolution X-ray crystal structures of the RNase A in complex with three most potent inhibitors of these inhibitors have shown that they bind at the enzyme catalytic cleft with the pyrimidine nucleobase at the B₁ subsite while the triazole moiety binds at the main subsite P₁, where P-O5′ bond cleavage occurs, and the ribose at the interface between subsites P₁ and P₀ exploiting interactions with residues from both subsites. The effect of a susbsituent group at the 5-pyrimidine position at the inhibitory potency has been also examined and results show that any addition at this position leads to a less efficient inhibitor. Comparative structural analysis of these RNase A complexes with other similar RNase A—ligand complexes reveals that the triazole moiety interactions with the protein form the structural basis of their increased potency. The insertion of a triazole linker between the pyrimidine base and the ribose forms the starting point for further improvement of these inhibitors in the quest for potent ribonucleolytic inhibitors with pharmaceutical potential.     

Universal ITS2 Barcoding DNA Region Coupled with High-Resolution Melting (HRM) Analysis for Seed Authentication and Adulteration Testing in Leguminous Forage and Pasture Species

Legume species are part of a very important agricultural family, second only to cereals. Their importance for sustainable agriculture worldwide comes from their nitrogen-fixing ability. They include mainly annual grain crops and also very important perennial forage and pasture species. Given their small size, seed admixture and adulteration are a common problem, lowering the forage value, creating weed components in the grassland and causing digestive problems to animals. Here we report the application of the Barcode-DNA High-Resolution Melting (Bar-HRM) analysis method using the universal nuclear plant DNA barcoding region ITS2 for the identification, adulteration and quantification of the main pasture species. Bar-HRM detected Medicago lupulina adulterants in Trifolium pratense seeds as low as 1:100. In conclusion, Bar-HRM analysis could be a faster with higher resolution and cost-effective alternative method to authenticate forage and pasture species and quantitatively detect the purity of their seeds or their feed products.     

Clustering biomolecular complexes by residue contacts similarity

Inaccuracies in computational molecular modeling methods are often counterweighed by brute-force generation of a plethora of putative solutions. These are then typically sieved via structural clustering based on similarity measures such as the root mean square deviation (RMSD) of atomic positions. Albeit widely used, these measures suffer from several theoretical and technical limitations (e.g., choice of regions for fitting) that impair their application in multicomponent systems (N > 2), large-scale studies (e.g., interactomes), and other time-critical scenarios. We present here a simple similarity measure for structural clustering based on atomic contacts--the fraction of common contacts--and compare it with the most used similarity measure of the protein docking community--interface backbone RMSD. We show that this method produces very compact clusters in remarkably short time when applied to a collection of binary and multicomponent protein-protein and protein-DNA complexes. Furthermore, it allows easy clustering of similar conformations of multicomponent symmetrical assemblies in which chain permutations can occur. Simple contact-based metrics should be applicable to other structural biology clustering problems, in particular for time-critical or large-scale endeavors.     

BM88 is a dual function molecule inducing cell cycle exit and neuronal differentiation of neuroblastoma cells via cyclin D1 down-regulation and retinoblastoma protein hypophosphorylation

Control of cell cycle progression/exit and differentiation of neuronal precursors is of paramount importance during brain development. BM88 is a neuronal protein associated with terminal neuron-generating divisions in vivo and is implicated in mechanisms underlying neuronal differentiation. Here we have used mouse neuroblastoma Neuro 2a cells as an in vitro model of neuronal differentiation to dissect the functional properties of BM88 by implementing gain- and loss-of-function approaches. We demonstrate that stably transfected cells overexpressing BM88 acquire a neuronal phenotype in the absence of external stimuli, as judged by enhanced expression of neuronal markers and neurite outgrowth-inducing signaling molecules. In addition, cell cycle measurements involving cell growth assays, BrdUrd incorporation, and fluorescence-activated cell sorting analysis revealed that the BM88-transfected cells have a prolonged G(1) phase, most probably corresponding to cell cycle exit at the G(0) restriction point, as compared with controls. BM88 overexpression also results in increased levels of the cell cycle regulatory protein p53, and accumulation of the hypophosphorylated form of the retinoblastoma protein leading to cell cycle arrest, with concomitant decreased levels and, in many cells, cytoplasmic localization of cyclin D1. Conversely, BM88 gene silencing using RNA interference experiments resulted in acceleration of cell proliferation accompanied by impairment of retinoic acid-induced neuronal differentiation of Neuro 2a cells. Taken together, our results suggest that BM88 plays an essential role in regulating cell cycle exit and differentiation of Neuro 2a cells toward a neuronal phenotype and further support its involvement in the proliferation/differentiation transition of neural stem/progenitor cells during embryonic development.     

Weather impacts on respiratory infections in Athens, Greece

In this study the contribution of meteorological parameters to the total variability of respiratory infections (RI) is analysed. For this purpose, data on the daily numbers of general practitioner (GP) consultations for RI during the year 2002 were used. This dataset has been compiled by the Local Health Service in the surroundings of Athens, Greece (Acharnes city). The meteorological data obtained by the Meteorological Station of the National Observatory of Athens comprise daily values of mean, maximum, and minimum air temperature, air temperature range, relative humidity, absolute humidity, sunshine, surface atmospheric pressure, wind speed, as well as day-to-day changes of these parameters. Furthermore, the following biometeorological parameters and thermal indices were also evaluated: mean radiant temperature (T _mrt), predicted mean vote (PMV), physiologically equivalent temperature (PET) and standard effective temperature (SET*) as well as their day-to-day changes. First, the relationship between every meteorological-biometeorological parameter and consultations for RI was examined by applying the Pearson Chi-Square Test (χ ²) to the data of the 25 compiled contingency tables. In the second stage, the application of generalised linear models (GLM) with Poisson distribution to the data revealed how much the weather variability leads to statistically important changes in consultations for RI. The results of this study contribute to the evidence that there is an association between weather conditions and the number of GP consultations for RI. More specifically, the influence of air temperature and absolute humidity on consultations on the same day is weaker than the lag effect (∼2 weeks) related to cold existence and absolute humidity, while a strong wind during the preceding 3 days drives a peak in GP consultations.     

2-Oxoamide inhibitors of phospholipase A2 activity and cellular arachidonate release based on dipeptides and pseudodipeptides

A series of 2-oxoamides based on dipeptides and pseudodipeptides were synthesized and their activities towards two human intracellular phospholipases A₂ (GIVA cPLA₂ and GVIA iPLA₂) and one human secretory phospholipase A₂ (GV sPLA₂) were evaluated. Derivatives containing a free carboxyl group are selective GIVA cPLA₂ inhibitors. A derivative based on the ethyl ester of an ether pseudodipeptide is the first 2-oxoamide, which preferentially inhibits GVIA iPLA₂. The effect of 2-oxoamides on the generation of arachidonic acid from RAW 264.7 macrophages was also studied and it was found that selective GIVA cPLA₂ inhibitors preferentially inhibited cellular arachidonic acid release; one pseudodipeptide gave an IC₅₀ value of 2 μM.