Dietary and toxicity exposure of emerging persistent organic pollutants to human health through consumption of cereal crops from Pakistan

There is a lack of scientific literature regarding the bioaccumulation, dietary, and toxicity exposure of emerging persistent organic pollutants through food crops. The current mini-review presents the dietary intake, spatial distribution pattern, and screening-levels risk assessment of persistent organic pollutants (POPs) in the cereal crops and environmental compartments from Punjab Province, Pakistan. Results of congener specific analysis were in accordance to the previously reported pattern of detected POPs across the globe. Spatial distribution was influenced by the industrial and urban fraction and trend of spatial distribution pattern was observed as follows: industrial/urban areas > industrial/peri-urban areas > agricultural/rural areas. Dietary intake of Organochlorine pesticides (OCPs) via consumption of cereal crops was observed higher and was in accordance to the previously reported levels while human health was at marginal risk to cancer. The results of dietary and toxicity exposure of detected POPs warrant auxiliary devotion in future, to this group of contaminants.     

Epidemiology of Enterovirus D68 in Ontario

In August 2014, children’s hospitals in Kansas City, Missouri and Chicago, Illinois notified the Centers for Disease Control and Prevention (CDC) about increased numbers of pediatric patients hospitalized with severe respiratory illness (SRI). In response to CDC reports, Public Health Ontario Laboratories (PHOL) launched an investigation of patients being tested for enterovirus D-68 (EV-D68) in Ontario, Canada. The purpose of this investigation was to enhance our understanding of EV-D68 epidemiology and clinical features. Data for this study included specimens submitted for EV-D68 testing at PHOL from September 1, 2014 to October 31, 2014. Comparisons were made between patients who tested positive for the virus (cases) and those testing negative (controls). EV-D68 was identified in 153/907 (16.8%) of patients tested. In the logistic regression model adjusting for age, sex, setting and time to specimen collection, individuals younger than 20 years of age were more likely to be diagnosed with EV-D68 compared to those 20 and over, with peak positivity at ages 5–9 years. Cases were not more likely to be hospitalized than controls. Cases were more likely to be identified in September than October (OR 8.07; 95% CI 5.15 to 12.64). Routine viral culture and multiplex PCR were inadequate methods to identify EV-D68 due to poor sensitivity and inability to differentiate EV-D68 from other enterovirus serotypes or rhinovirus. Testing for EV-D68 in Ontario from July to December, 2014 detected the presence of EV-D68 virus among young children during September-October, 2014, with most cases detected in September. There was no difference in hospitalization status between cases and controls. In order to better understand the epidemiology of this virus, surveillance for EV-D68 should include testing of symptomatic individuals from all treatment settings and patient age groups, with collection and analysis of comprehensive clinical and epidemiological data.     

Adipocytokine Profile,Cytokine Levels and Foxp3 Expression in Multiple Sclerosis: a Possible Link to Susceptibility and Clinical Course of Disease

Background

Adipocytokines may be involved in multiple sclerosis (MS) as well as other autoimmune and inflammatory-related diseases. This study aims to compare levels of resistin, visfatin and leptin in three subgroups of MS patients with healthy subjects and also to study their relationship with Foxp3 expression and levels of several pro-inflammatory mediators such as interleukine-1 β(IL-1 β),tumor necrosis factor-α (TNF-α) and human sensitive C-reactive protein (hs-CRP).

Methods

A total of 391 subjects including 200 healthy controls and 191 MS patients were recruited for this case-control study. Circulating adipocytokines and inflammatory mediators were measured using immunoassay methods. Foxp3 gene expression in peripheral blood mononuclear cells (PBMC) was determined by quantitative real-time PCR. Fat tissue mass was evaluated by using dual energy X-ray absorptiometery (DEXA).

Results

A significant difference was observed in levels of inflammatory mediators, adipocytokines, Foxp3 gene expression and adipose tissue mass between MS patients and healthy controls. All adipocytokines were positively correlated with levels of inflammatory mediators and negatively correlated with Foxp3 expression in MS patients. In controls, there were positive correlations between circulating leptin and resistin with TNF-α and IL-1β in subgroup analysis, the highest levels of TNF-α, IL-1β, hs-CRP, resistin and leptin were observed in primary progressive-MS (PP-MS) patients. Also, expression of Foxp3 and levels of visfatin in relapsing remitting-MS(RR-MS) patients were higher compared with the other subgroups.

Conclusions

Our findings suggest the potential role of adipocytokines in pathogenesis and severity of MS. Notably, the relationship of adipocytokines levels with inflammatory cytokines as well as clinical features of MS could be considerable in translational medicine and biomarker studies.     

Novel delivery systems for interferons

Interferons, IFNs, are among the most widely studied and clinically used biopharmaceuticals. Despite their invaluable therapeutic roles, the widespread use of IFNs suffers from some inherent limitations, mainly their relatively short circulation lifespan and their unwanted effects on some non-target tissues. Therefore, both these constraints have become the central focus points for the research efforts on the development of a variety of novel delivery systems for these therapeutic agents with the ultimate goal of improving their therapeutic end-points. Generally, the delivery systems currently under investigation for IFNs can be classified as particulate delivery systems, including micro- and nano-particles, liposomes, minipellets, cellular carriers, and non-particulate delivery systems, including PEGylated IFNs, other chemically conjugated IFNs, immunoconjugated IFNs, and genetically conjugated IFNs. All these strategies and techniques have their own possibilities and limitations, which should be taken into account when considering their clinical application. In this article, currently studied delivery systems/techniques for IFN delivery have been reviewed extensively, with the main focus on the pharmacokinetic consequences of each procedure.     

Carbon nanotube/polyurethane modified hollow fiber‐pencil graphite electrode for in situ concentration and electrochemical quantification of anticancer drugs Capecitabine and Erlotinib

A sensitive electrochemical sensor has been designed for in situ preconcentration and determination of anticancer drugs Capecitabine (CPT) and Erlotinib hydrochloride (ETHC) based on a pencil graphite electrode modified with multivalued carbon nanotube—polyurethane (MWCNT‐PUFIX) nanocomposite that was supported with a piece of polypropylene hollow fiber (HF‐PGE). The electrochemical behavior of CPT and ETHC on the MWCNT‐PUFIX/HF‐PGE modified electrode was investigated by differential pulse voltammetry (DPV) techniques and the obtained results confirmed its efficiency for sensing of CPT and ETHC. The synthesized nanocomposite was characterized by infrared spectroscopy and scanning electron microscope. After optimization of some effective parameters on the method efficiency including pH, nanocomposite amount, the type of organic solvent, scan rate and the effect of some additives, the mentioned sensor presented suitable results for determination of CPT and ETHC with the linear ranges from 7.70 to 142.00 μM and 0.11 to 23.50 μM and detection limits of 0.11 and 0.02 μM, respectively. Also, the fabricated sensor has shown good performance in analysis of CPT and ETHC in biological samples.     

Focal Adhesion Kinase Plays a Role in Osteoblast Mechanotransduction In Vitro but Does Not Affect Load-Induced Bone Formation In Vivo

A healthy skeleton relies on bone''s ability to respond to external mechanical forces. The molecular mechanisms by which bone cells sense and convert mechanical stimuli into biochemical signals, a process known as mechanotransduction, are unclear. Focal adhesions play a critical role in cell survival, migration and sensing physical force. Focal adhesion kinase (FAK) is a non-receptor protein tyrosine kinase that controls focal adhesion dynamics and can mediate reparative bone formation in vivo and osteoblast mechanotransduction in vitro. Based on these data, we hypothesized that FAK plays a role in load-induced bone formation. To test this hypothesis, we performed in vitro fluid flow experiments and in vivo bone loading studies in FAK−/− clonal lines and conditional FAK knockout mice, respectively. FAK−/− osteoblasts showed an ablated prostaglandin E₂ (PGE₂) response to fluid flow shear. This effect was reversed with the re-expression of wild-type FAK. Re-expression of FAK containing site-specific mutations at Tyr-397 and Tyr-925 phosphorylation sites did not rescue the phenotype, suggesting that these sites are important in osteoblast mechanotransduction. Interestingly, mice in which FAK was conditionally deleted in osteoblasts and osteocytes did not exhibit altered load-induced periosteal bone formation. Together these data suggest that although FAK is important in mechanically-induced signaling in osteoblasts in vitro, it is not required for an adaptive response in vivo, possibly due to a compensatory mechanism that does not exist in the cell culture system.     

A simple strategy towards membrane protein purification and crystallization

A simple and cost-efficient detergent screening strategy has been developed, by which a number of detergents were screened for their efficiency to extract and purify the recombinant ammonium/ammonia channel, AmtB, from Escherichia coli, hence selecting the most efficient detergents prior to large-scale protein production and crystallization. The method requires 1 ml cell culture and is a combination of immobilized metal ion affinity chromatography and filtration steps in 96-well plates. Large-scale protein purification and subsequent crystallization screening resulted in AmtB crystals diffracting to low resolution with three detergents. This strategy allows exclusion of detergents with the lowest probability in yielding protein crystals and selecting those with higher probability, hence, reducing the number of detergents to be screened prior to large-scale membrane protein purification and perhaps also crystallization.     

High-level expression, purification, and crystallization of recombinant rat leukotriene C(4) synthase from the yeast Pichia pastoris

Chemical-enzymatic synthesis of human Epidermal Growth Factor (hEGF) cDNA has been performed, following by cloning into expression vector pTWIN1 (New England Biolabs). The resulting recombinant fusion protein expressed in Escherichia coli consisted of the N-terminal chitin-binding domain, mini-intein Ssp dnaB domain and hEGF polypeptide at the C-terminus. In this construct, mini-intein Ssp dnaB played a role of catalytically active subunit capable under certain conditions of autocatalytic cleavage resulting in separation of the target protein. As the hybrid protein had several cysteins in its sequence-one in chitin-binding domain, one in mini-intein and six in hEGF, it was necessary to work out optimal scheme for refolding and purification of the recombinant hEGF. As a result of this work, two schemes of the recombinant hEGF purification have been developed: according to the first scheme, the recombinant protein with reduced cysteins is bound to the chitin column, the hEGF is cleaved off and eluted, and then refolded to form appropriate cystein bridges. In the second scheme, the entire hybrid protein is first refolded to form disulfide bonds and then loaded to affinity resin; the recombinant hEGF is cleaved off and eluted in its native state. In spite of the fact that the first scheme is more common and suitable for a variety of recombinant proteins, in case of recombinant hEGF, the second scheme proved to be more productive and cost-effective.     

Catalysis within the lipid bilayer-structure and mechanism of the MAPEG family of integral membrane proteins

Integral membrane enzymes of the MAPEG (membrane-associated proteins in eicosanoid and glutathione metabolism) family catalyze glutathione-dependent transformations of lipophilic substrates harvested from the lipid bilayer. Recent studies of members of this family have yielded extensive insights into the structural basis for their substrate binding and catalytic activity. Most informative are the structural studies of leukotriene C4 synthase, revealing a narrow hydrophobic substrate binding pocket allowing extensive recognition of the aliphatic chain of the LTA(4) substrate. A key feature of the pocket is a tryptophan residue that pins down the omega-end of the aliphatic chain into the active site. Since MAPEG members cannot utilize a hydrophobic effect for substrate binding, this novel mode of substrate recognition appears well suited for harvesting lipophilic substrates from the membrane. The binding mode also allows for the specific alignment of the substrate in the active site, positioning the C6 of the substrate for conjugation with glutathione. The glutathione is in turn bound in a polar pocket submerged into the protein core. Structure-based sequence alignments of human MAPEG members support the notion that the glutathione binding site is highly conserved among MAPEG enzymes and that they use a similar mechanism for glutathione activation.