Proteome-guided search for influenza A B-cell epitopes

The influenza A linear peptide epitopes recognized by murine antibodies, and currently cataloged at http://www.immuneepitope.org , were examined for the identity score to the host mouse proteome. It was found that almost all of the linear viral determinants are (or contain) regions formed by pentapeptide fragments with no or only very low similarity to the murine proteins. The present study adds to previous reports in suggesting a main role of amino acid sequence similarity in the modulation and definition of the B-cell epitope repertoire, inspiring innovative vaccine approaches able to avoid cross-reactive autoimmune collateral phenomena, and addressing future research in the study of immunity against the influenza A virus and infectious diseases in general.     

Control of rabies in Slovenia

Red foxes (Vulpes vulpes) are the main reservoir of rabies in Slovenia, whereas cases of rabies in other wildlife species occur sporadically. In 1995, a program of oral vaccination of wildlife in Slovenia was initiated; baits with oral vaccine were distributed by air at a density of 20 baits/km(2). During 1995, when the oral vaccination program was started, 1,089 cases of rabies (including both wild and domestic animals) were reported. Five years later (1999), only six positive animals were detected among 1,195 tested (0.5%). Despite an increase in bait density (25 baits/km(2)) during the years 2000 and 2001, reported rabies cases increased to 115 and 135, respectively. In 2003, following initiation of a new bait-dropping strategy, which incorporated perpendicular rather than parallel flight lines, the number of rabies cases decreased to eight.     

Algal community patterns in Slovenian bogs along environmental gradients

In 2005 and 2006, epiphyton samples were collected from seven lowland and montane peat bogs in Slovenia. Water temperature, pH, conductivity, dissolved oxygen and saturation were measured at the same time. Diatoms, desmids and Cyanobacteria were the most abundand groups in species number. Canonical Correspondence Analysis (CCA) was carried out on Cyanobacteria, diatom and desmid flora composition. This analysis showed that shading was the most important parameter in Cyanobacteria distribution and bedrock the most important one in that of diatoms and desmids. Cluster analyses were carried out based on the Cyanobacteria, diatom and desmid data. The Cyanobacteria and diatom data separated sites, whereas the desmid data revealed a temporal aspect.     

Enantiomeric determination of tramadol and O-desmethyltramadol in human plasma by fast liquid chromatographic technique coupled with mass spectrometric detection

A rapid and sensitive method using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for enantiomeric determination of tramadol and its primary phase metabolite O-desmethyltramadol in human plasma has been developed. Tramadol hydrochloride – ¹³C, d_3, was used as an isotopic labeled internal standard for quantification. The method involves a simple solid phase extraction. The analytes and internal standard were separated on Lux Cellulose-2 packed with cellulose tris(3-chloro-4-methylphenylcarbamate) using isocratic elution with hexane/isopropanol/diethylamine (90:10:0.1, v/v/v) at a flow rate of 1.3 mL/min. The APCI positive ionization mass spectrometry was used with multiple reaction monitoring of the transitions at m/z 264.2 → 58.2 for tramadol, m/z 250.1 → 58.2 for O-desmethyltramadol and m/z 268.2 → 58.2 for internal standard. Linearity was achieved between 1–800 ng/mL and 1–400 ng/mL (R² ≥ 0.999) for each enantiomer of tramadol and O-desmethyltramadol, respectively. Intra-day accuracies ranged among 98.2–102.8%, 97.1–109.1% and 97.4–102.9% at the lower, intermediate, and high concentration for all analytes, respectively. Inter-day accuracies ranged among 95.5–104.1%, 99.2–104.7%, and 94.2–105.6% at the lower, intermediate, and high concentration for all analytes, respectively. This assay was successfully used to determine the concentration of enantiomers of tramadol and O-desmethyltramadol in a pharmacogenetic study.     

Negative regulation of cytoplasmic RNA-mediated antiviral signaling

The recent, rapid progress in our understanding of cytoplasmic RNA-mediated antiviral innate immune signaling was initiated by the discovery of retinoic acid-inducible gene I (RIG-I) as a sensor of viral RNA. It is now widely recognized that RIG-I and related RNA helicases, melanoma differentiation-associated gene-5 (MDA5) and laboratory of genetics and physiology-2 (LGP2), can initiate and/or regulate RNA and virus-mediated type I IFN production and antiviral responses. As with other cytokine systems, production of type I IFN is a transient process, and can be hazardous to the host if unregulated, resulting in chronic cellular toxicity or inflammatory and autoimmune diseases. In addition, the RIG-I-like receptor (RLR) system is a fundamental target for virus-encoded immune suppression, with many indirect and direct examples of interference described. In this article, we review the current understanding of endogenous negative regulation in RLR signaling and explore direct inhibition of RLR signaling by viruses as a host immune evasion strategy.     

The impact of long-term past exposure to elemental mercury on antioxidative capacity and lipid peroxidation in mercury miners

Limited information is available on the effects of chronic mercury exposure in relation to the risk of cardiovascular disease (CVD). It is known from in vitro and in vivo studies that Hg can promote lipid peroxidation through promotion of free radical generation, and interaction with antioxidative enzymes and reduction of bioavailable selenium. The objective of the study was to test the hypothesis that long-term past occupational exposure to elemental Hg (Hg⁰) can modify antioxidative capacity and promote lipid peroxidation in miners.

The study population comprised 54 mercury miners and 58 workers as the control group. The miners were examined in the post-exposure period. We evaluated their previous exposure to Hg⁰, the putative appearance of certain nonspecific symptoms and signs of micromercurialism, as well as the main behavioural and biological risk factors for CVD, and determined: 1) Hg and Se levels in blood and urine, 2) antioxidative enzymes, Cu/Zn superoxide dismutase (CuZn-SOD), catalase (CAT), and selenoenzyme glutathione peroxidase (GSH-Px) activity in erythrocytes as indirect indices of free radical activity, 3) pineal hormone melationin (MEL) in blood and urine, and 4) lipid hydroperoxides (LOOHs) and malondialdehyde (MDA) as lipid peroxidation products.

The mercury miners were intermittently exposed to Hg⁰ for periods of 7 to 31 years. The total number of exposure periods varied from 13 to 119. The cumulative U-Hg peak level varied from 794-11,365 μg/L. The current blood and urine Hg concentrations were practically on the same level in miners and controls. Miners showed some neurotoxic and nephrotoxic sequels of micromercurialism. No significant differences in behavioural and biological risk factors for CVD were found between miners and controls. A weak correlation (r = 0.36, p < 0.01) between systolic blood pressure and average past exposure U-Hg level was found. The mean P-Se in miners (71.4 μg/L) was significantly lower (p < 0.05) than in the controls (77.3 μg/L), while the mean U-Se tended to be higher (p < 0.05) in miners (16.5 μg/g creatinine) than in the controls (14.0 μg/g creatinine). Among antioxidative enzyme activities, only CAT in erythrocytes was significantly higher (p < 0.01) in miners (3.14 MU/g Hb) than in the controls (2.65 MU/g Hb). The mean concentration of B-MEL in miners (44.3 ng/L) was significantly higher (p < 0.01) than in the controls (14.9 ng/L). The mean value of U-MEL sulphate (31.8 μg/L) in miners was significantly lower (p < 0.01) than in the control group (46.9 μg/L). Among the observed lipid peroxidative products, the mean concentration of U-MDA was statistically higher (p < 0.01) in miners (0.21 μmol/mmol creatinine) than in the controls (0.17 μmol/mmol creatinine).

In the group of miners with high mercury accumulation and the presence of some nonspecific symptoms and signs of micromercurialism, the results of our study partly support the assumption that long-term occupational exposure to Hg⁰ enhances the formation of free radicals even several years after termination of occupational exposure. Therefore, long-term occupational exposure to Hg⁰ could be one of the risk factors for increased lipid peroxidation and increased mortality due to ischaemic heart disease (ICH) found among the mercury miners of the Idrija Mine.     

Engineered microenvironments for human stem cells

Regulation of cell differentiation and assembly remains a fundamental question in developmental biology. During development, tissues emerge from coordinated sequences of the renewal, differentiation, and assembly of stem cells. Likewise, regeneration of an adult tissue is driven by the migration and differentiation of repair cells. The fields of stem cells and regenerative medicine are starting to realize how important is the entire context of the cell environment, with the presence of other cells, three‐dimensional matrices, and sequences of molecular and physical morphogens. The premise is that to unlock the full potential of stem cells, at least some aspects of the dynamic environments normally present in vivo need to be reconstructed in experimental systems used in vitro. We review here some recent work that utilized engineered environments for guiding the embryonic and adult human stem cells, and focus on vasculogenesis as a critical and universally important aspect of tissue development and regeneration. Birth Defects Research (Part C) 84:335–347, 2008. © 2008 Wiley‐Liss, Inc.     

Engineering custom-designed osteochondral tissue grafts

Tissue engineering is expected to help us outlive the failure of our organs by enabling the creation of tissue substitutes capable of fully restoring the original tissue function. Degenerative joint disease, which affects one-fifth of the US population and is the country's leading cause of disability, drives current research of actively growing, functional tissue grafts for joint repair. Toward this goal, living cells are used in conjunction with biomaterial scaffolds (serving as instructive templates for tissue development) and bioreactors (providing environmental control and molecular and physical regulatory signals). In this review, we discuss the requirements for engineering customized, anatomically-shaped, stratified grafts for joint repair and the challenges of designing these grafts to provide immediate functionality (load bearing, structural support) and long-term regeneration (maturation, integration, remodeling).