Oxidative stress in diabetes: a mechanistic overview of its effects on atherogenesis and myocardial dysfunction

Diabetes is a major risk factor for atherosclerosis. Atherogenesis involves endothelial dysfunction, activation and injury, inflammation, and smooth muscle cell migration and proliferation. Platelet activation in the narrowed arteries is the most proximate event in the culmination of an acute event such as acute myocardial infraction and stroke. Hyperglycemia is associated with all these adverse events in the process of genesis of atherosclerosis. The effect of diabetes (hyperglycemia) is mediated in large part by the state of enhanced oxidative stress, which is not counter-balanced by endogenous antioxidants. This paper reviews the ignition of oxidative stress in diabetes and the mediation of events leading to atherogenesis.     

Apolipoprotein E-mediated immune regulation in sepsis

Lipids and lipoproteins have emerged as key constituents of the immune response to microbial infection. We, therefore, sought to understand the complex interaction between lipoprotein metabolism and sepsis. Apolipoprotein E (apoE), a component of plasma lipoproteins, has been suggested to bind and traffic Ags for NKT cell activation. However, apoE's role in sepsis has not been demonstrated. In this study, we examined the effect of exogenous apoE in a rat model of septic peritonitis, induced by cecal ligation and puncture. We demonstrate that 48 h after serial injections of apoE, septic mortality increased in a dose-dependent manner. While sepsis resulted in increased splenic and decreased hepatic and circulating NKT cell populations, serial injections of apoE for 24 h after cecal ligation and puncture increased the frequency, cell number, and BrdU uptake in splenic and hepatic NKT cell populations, while concomitantly depleting these populations in the circulation. These changes were correlated with elevated alanine amino transferase levels, an indicator of liver injury. Interestingly, while sepsis increased hepatic T cell apoptosis and necrosis, apoE reversed these changes. apoE also promoted increases in predominantly Th1 cytokine levels in sera and a decrease in IL-4, the main NKT cell-derived Th2 cytokine. Consequently, apoE treatment is associated with increased sepsis-induced mortality, and increased NKT cell frequency and proliferation in the liver and spleen, with concomitant decreases in these NKT cell parameters in the peripheral circulation. apoE treatment also promoted a Th1 cytokine response, increased the degree of liver injury, and decreased apoptosis in hepatic lymphocytes.     

Superovulation and embryo transfer in wood bison (Bison bison athabascae)

Two experiments were done to develop an effective superovulatory treatment protocol in wood bison for the purpose of embryo collection and transfer. In experiment 1, donor bison were assigned randomly to four treatment groups (N = 5 per group) to examine the effects of method of synchronization (follicular ablation vs. estradiol-progesterone treatment) and ovarian follicular superstimulation (single slow-release vs. split dose of FSH). Recipient bison were synchronized with donor bison by either follicular ablation (N = 8) or estradiol-progesterone treatment (N = 9). In experiment 2, bison were assigned randomly to four treatment groups (N = 5 per group) to examine the ovarian response to two versus four doses of FSH, and the effect of progesterone (ovarian superstimulation with or without an intravaginal progesterone-releasing device). Donor bison were inseminated with fresh chilled wood bison semen 12 and 24 hours after treatment with GnRH (experiment 1) or LH (experiment 2). The ovarian response was assessed using ultrasonography. In experiment 1, the number of large follicles (≥7 mm) increased in response to both FSH treatments, but the diameter of the largest follicle detected 4 and 5 days after the start of ovarian superstimulation was greater in bison treated with a single dose of FSH than in those treated with two doses (P < 0.05). A total of 10 ova and/or embryos were collected. One blastocyst was transferred to each of five recipient bison resulting in the birth of two live wood bison calves. In experiment 2, two doses of FSH resulted in a greater number of large follicles (≥9 mm) on Days 4, 5, and 6 (P < 0.05) after beginning of superstimulation (Day 0), and more ovulations than four doses of FSH (11.2 ± 2.4 vs. 6.4 ± 0.8; P < 0.05). Embryo collection was performed on only five donors, and a total of 19 ova and/or embryos were recovered. In summary, fewer FSH treatments were as good or better than multiple treatments, consistent with the notion that minimizing handling stress improves the superovulatory response in bison. Follicular ablation and estradiol plus progesterone treatment were effective for inducing ovarian synchronization in embryo donor and recipient bison, and an intravaginal progesterone-releasing device during superstimulatory treatment did not influence the superovulatory response or embryo collection. Delaying ovulation-inducing treatment (GnRH or LH) to 5 days after superstimulatory treatment resulted in a greater number of ovulations and improved embryo collection efficiency (experiment 2). Embryo collection and transfer resulted in live offspring from wild wood bison.     

MATIN: A Random Network Coding Based Framework for High Quality Peer-to-Peer Live Video Streaming

In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.     

Epidemiology of pediatric primary malignant central nervous system tumors in Iran: A 10 year report of National Cancer Registry

BackgroundCNS tumors are the leading cause of cancer related deaths among children and adolescents. Nonetheless, the incidence of pediatric CNS tumors in developing countries is poorly understood. We aimed to provide epidemiologic features of primary malignant CNS tumors in Iranian children 0–19 years of age using National Cancer Registry (NCR) data bank.MethodsThe data recorded by NCR over a 10 year period (2000–2010) were reviewed.ResultsOf 1948 tumor cases, 93.3% were located in brain, 5.1% were found in the spinal cord & cauda equina, and 1.6% affected cranial nerves and other parts of the nervous system. The overall average annual age specific incidence rate was 1.43 per 100,000. Males were more likely to develop CNS tumors (1.65 per 100,000) compared to females (1.21 per 100,000, p < 0.01). Children under 5 years of age had the highest age specific incidence rate (1.86 per 100,000). Astrocytic tumors with the incidence rate of 0.61 per 100,000 were the most frequent specific histology followed by embryonal (0.38 per 100,000), and ependymal tumors (0.10 per 100,000). With regard to the histological distribution of tumors, some unique features including the high proportion of unspecified malignant neoplasms (7.6%) were noted.ConclusionThe overall incidence rate was markedly lower than western findings. Major differences were also observed in incidence rates of specific histologies. Although the discrepancies may be attributable to diversity in classification schemes and registration practices, a real ethnic and geographical variation in predisposition to development of pediatric CNS cancers is strongly suggested.     

Vavilosides A1/A2–B1/B2, new furostane glycosides from the bulbs of Allium vavilovii with cytotoxic activity

A phytochemical analysis of the bulbs of Allium vavilovii M. Pop. & Vved. was attained for the first time extensively, affording to the isolation of four new furostanol saponins, named vavilosides A1/A2–B1/B2 (1a/b–2a/2b), as two couple of isomers in equilibrium, together with ascalonicoside A1/A2 (3a/3b) and 22-O-methyl ascalonicoside A1/A2 (4a/4b), previously isolated from shallot, Allium ascalonicum. High concentrations of kaempferol, kaempferide, and kaempferol 4^I-glucoside were also isolated. The chemical structures of the new compounds, established through a combination of extensive nuclear magnetic resonance, mass spectrometry and chemical analyses, were identified as (25R)-furost-5(6)-en-1β,3β,22α,26-tetraol 1-O-α-l-rhamnopyranosyl-(1→2)-O-β-d-galactopyranosyl 26-O-α-l-rhamnopyranoside (vaviloside A1), (25R)-furost-5(6)-en-1β,3β,22β,26-tetraol 1-O-α-l-rhamnopyranosyl-(1→2)-O-β-d-galactopyranosyl 26-O-α-l-rhamnopyranoside (vaviloside A2), (25R)-furost-5(6)-en-1β,3β,22α,26-tetraol 1-O-α-l-rhamnopyranosyl-(1→2)-O-β-d-xylopyranosyl 26-O-α-l-rhamnopyranoside (vaviloside B1), (25R)-furost-5(6)-en-1β,3β,22β,26-tetraol 1-O-α-l-rhamnopyranosyl-(1→2)-O-β-d-xylopyranosyl 26-O-α-l-rhamnopyranoside (vaviloside B2). The isolated saponins showed cytotoxic activity on J-774, murine monocyte/macrophage, and WEHI-164, murine fibrosarcoma, cell lines with the following rank: vaviloside B1/B2 > ascalonicoside A1/A2 > vaviloside A1/A2.     

A chemiluminescent metalloimmunoassay based on copper‐enhanced gold nanoparticles for quantification of human growth hormone

A chemiluminescence (CL) immunoassay was developed to determine human growth hormone (hGH) based on copper‐enhanced gold nanoparticles. In this method, gold nanoparticles were deposited on polystyrene wells for adsorption of human growth antibodies as well as catalyst for reducing of copper ions from the copper enhancer solution. The reduction of copper ions was prevented where the gold nanoparticles were covered by the antibody–antigen immunocomplex. The deposited copper on Au nanoparticles was then dissolved in HNO₃ solution and quantified using the CL method. The CL intensity response was logarithmically dependent on the hGH concentrations over the range 0.2–50 ng/mL, with a detection limit (3σ) of 0.036 ng/mL. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparing different sterol containing solid lipid nanoparticles for targeted delivery of quercetin in hepatocellular carcinoma

Quercetin (QT) is a potential chemotherapeutic drug with low solubility that seriously limits its clinical use. The aim of this study was enhancing cellular penetration of QT by sterol containing solid lipid nanoparticles (SLNs) which make bilayers fluent for targeting hepatocellular carcinoma cells. Three variables including sterol type (cholesterol, stigmasterol and stigmastanol), drug and sterol content were studied in a surface response D-optimal design for preparation of QT-SLNs by emulsification solvent evaporation method. The studied responses included particle size, zeta potential, drug loading capacity and 24?h release efficiency (RE₂₄%). Scanning electron and atomic force microscopy were used to study the morphology of QT-SLNs and their thermal behavior was studied by DSC analysis. Cytotoxicity of QT-SLNs was determined by MTT assay on HepG-2 cells and cellular uptake by fluorescence microscopy method. Optimized QT-SLNs obtained from cholesterol and QT with the ratio of 2:1 that showed particle size of 78.0?±?7.0?nm, zeta potential of??22.7?±?1.3?mV, drug loading efficiency of 99.9?±?0.5% and RE₂₄ of 56.3?±?3.4%. IC₅₀ of QT in cholesterol SLNs was about six and two times less than free QT and phytosterol SLNs, respectively, and caused more accumulation of QT in HepG2 cells. Blank phytosterol SLNs were toxic on cells.     

Comparative Analysis of Physio-Biochemical Responses to Cold Stress in Tetraploid and Hexaploid Wheat

The cellular changes induced by cold stress (CS) include responses that lead to oxidative stress and limits plant growth, metabolism, and productivity. In this study, responses of physio-biochemical to CS phases were comparatively studied in three genotypes of bread and durum wheats differing in sensitivity, two of them (Norstar, bread wheat and Gerdish, durum wheat) were tolerant to CS and the other one, SRN (durum wheat) was sensitive to CS. 14-day-old seedlings were subjected to CS (12 and 24 h) with or without cold acclimation (CA) phase. During CS, the elevated levels of electrolyte leakage index, contents of hydrogen peroxide (H₂O₂), and malondialdehyde in Norstar and Gerdish were lower than that of SRN plants. Positive correlation and co-regulation of reactive oxygen species (ROS) scavenging systems, superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and proline especially after CA phase suggested crucial role for holding back toxic ROS levels in CS phase. However, different activities of this system resulted in different intensities of oxidative stress in acclimated and non-acclimated plants. Our results showed that a CA phase induced oxidative stress tolerance by modulating antioxidative systems. These responses confirmed the existence of wide range of genetic capacity in durum wheat to increase cold tolerance particularly in Gerdish so that the sensitivity of SRN plants to CS was linearly correlated with the more decrease of antioxidant systems. These general responses may be a sign for associating other metabolites or enzymes activities to create partly tolerance against cold-induced oxidative stress. Eventually, assessing the dynamic of cell responses in short intervals after CS without CA phases profitably could be a novel path in plant stress response investigations in a short period of time.