Free Radical Scavenging Properties of Skin and Pulp Extracts of Different Grape Cultivars In Vitro and Attenuation of H2O2-Induced Oxidative Stress in Liver Tissue Ex Vivo

Grapes are the richest source of antioxidants due to the presence of potent bioactive phytochemicals. In this study, the phytochemical contents, scavenging activities and protective role against H₂O₂-induced oxidative stress in liver tissue ex vivo of four grape (Vitis vinifera) cultivars extracts, namely Flame seedless (black), Kishmish chorni (black with reddish brown), Red globe (red) and Thompson seedless mutant (green), were evaluated. The total phenolics and flavonoids content in pulp or skin fractions of different grape cultivars were in the range of 47.6–310 mg gallic acid equivalent/g fresh weight (fw), and 46.6–733.3 µg catechin equivalent/g fw respectively. The scavenging activities in skin of different grape varieties against 2,2-diphenyl-1-picrylhydrazyl (44–58 %), hydrogen peroxide (15.3–18.6 %), and hydroxyl radicals (50–85 %), were higher than pulp of the corresponding cultivars. These scavenging activities of grape extracts were found to be significantly (p < 0.01) correlated with the levels of total phenols, flavonoids and ascorbic acid. Liver tissues from goat treated with H₂O₂ (500 μM) showed significantly decreased GSH content by 42.9 % and activities of catalase by 50 % and glutathione reductase by 66.6 %; while increased thiobarbituric acid reactive substances and nitric oxide level by 2.53- and 0.86-fold, respectively, and activity of glutathione S-transferase by 0.96-fold. Grape skin extracts showed the stronger protective activity against H₂O₂-induced oxidative stress in liver tissue ex vivo, than its pulp of any cultivar; and the Flame seedless (black) cultivar showed the highest potential. In conclusion, our study suggested that the higher antioxidant potential, phytochemical contents and significant scavenging capacities in pulp and skin of grape extracts showed the protective action of grape extracts against H₂O₂-induced oxidative stress in liver tissue ex vivo.     

Interplay Between Inflammation and Hemostasis in Patients with Coronary Artery Disease

Coronary artery disease (CAD) is a global epidemic currently. This study was planned to evaluate markers of inflammation and hemostasis and their possible association, if any, in patients with CAD. The study was carried out in 60 patients with acute myocardial infarction (AMI) and 60 age and gender matched controls. The following parameters were assayed in all study subjects-inflammatory-interleukin (IL)-10, high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF)-α, fibrinogen; hemostatic-fibrinogen, fibrin D-dimer and a novel risk factor—homocysteine. Inflammatory markers (hs-CRP, TNF-α and IL-10), fibrinogen, fibrin D-dimer and homocysteine levels were significantly higher in the patients with AMI, as compared with controls. A positive correlation was observed between D-dimer and the inflammatory markers—hs-CRP and TNF-α. Upon multivariate analysis, TNF-α emerged as the best determinant of CAD in our study. Our results indicate that there is a possible interplay of inflammation and hemostasis in CAD, underlining their synergistic role in the pathogenesis of CAD.     

Association of Resistin with Insulin Resistance and Factors of Metabolic Syndrome in North Indians

Metabolic syndrome (MetS) is a cluster of interrelated common clinical disorders. The role of resistin in insulin sensitivity and MetS is controversial till date. So, the aim of the present study was to investigate the relationship of plasma resistin levels with markers of the MetS in Indian subjects. In a case control study, total 528 subjects were selected for the study. 265 (194 male and 71 female) were cases (with MetS) and 263 (164 male and 99 female) were controls (without MetS). Required anthropometric measurements and calculations were carried out accordingly. All the Biochemical estimations were carried out according to standard protocol. Resistin level was measured by the standard protocol (By ELISA i.e. enzyme linked immunosorbent assay) as illustrated in the kit. Insulin level was also measured by the standard protocol as illustrated in the kit and insulin resistance was calculated by the standard procedures. Plasma resistin levels were significantly higher in cases compared with controls (male = 13.05 ± 4.31 vs. 7.04 ± 2.09 ng/ml; p ≤ 0.001 and female = 13.53 ± 4.14 vs. 7.42 ± 2.30 ng/ml; p ≤ 0.001). Plasma resistin levels were well correlated with waist circumference, glucose, triglycerides, waist/hip ratio, systolic and diastolic blood pressure, high density lipoprotein, total cholesterol, serum low density lipoprotein, serum very low density lipoprotein, insulin and insulin resistance. Plasma resistin levels were elevated in presence of the MetS and were associated with increased metabolic risk factors.     

面向当代学习环境设计教学

日益变化的学习环境对设计教学提出了严峻的挑战。其中,最重要的是考虑如何面向现实生活和完整任务开展学习;如何学会解决非良构的问题,实现学习迁移;如何从扶到放设计学习任务;如何推行个性化的教学;本文概要地讨论了综合学习设计理论和认知负荷理论的若干重要主张和认识。     

High-throughput sorting of drops in microfluidic chips using electric capacitance

We analyze a recently introduced approach for the sorting of aqueous drops with biological content immersed in oil, using a microfluidic chip that combines the functionality of electrowetting with the high throughput of two-phase flow microfluidics. In this electrostatic sorter, three co-planar electrodes covered by a thin dielectric layer are placed directly below the fluidic channel. Switching the potential of the central electrode creates an electrical guide that leads the drop to the desired outlet. The generated force, which deflects the drop, can be tuned via the voltage. The working principle is based on a contrast in conductivity between the drop and the continuous phase, which ensures successful operation even for drops of highly conductive biological media like phosphate buffered saline. Moreover, since the electric field does not penetrate the drop, its content is protected from electrical currents and Joule heating. A simple capacitive model allows quantitative prediction of the electrostatic forces exerted on drops. The maximum achievable sorting rate is determined by a competition between electrostatic and hydrodynamic forces. Sorting speeds up to 1200 per second are demonstrated for conductive drops of 160 pl in low viscosity oil.     

Eye tracking as a tool to study and enhance multimedia learning

This special issue comprises a set of six papers, in which studies are presented that use eye tracking to analyse multimedia learning processes in detail. Most of the papers focus on the effects on visual attention of animations with different design features such as spoken vs. written text, different kinds of cues, or different presentation speeds. Two contributions concern effects of learner characteristics (prior knowledge) on visual attention when learning with video and complex graphics. In addition, in some papers eye tracking is not only used as a process measure in itself, but also as input for verbal reports (i.e., cued retrospective reporting). In the two commentaries, the contributions are discussed from a multimedia learning perspective and an eye tracking perspective, by prominent researchers in those fields. Together, the contributions to this issue give an overview of the various possibilities eye tracking opens up for research on multimedia learning and instruction.     

Status of Vitamin D Receptor Gene Polymorphism and 25-Hydroxy Vitamin D Deficiency with Essential Hypertension

Essential hypertension (EH) is a multifactorial and complex disease with high rate of incidence and associated co-morbidities. Previous studies do not provide unanimous results for the risk of hypertension and association with Fok I genotype frequency and serum vitamin D levels. Hence, this study was undertaken to determine the status of Fok I vitamin D receptor (VDR) gene polymorphism along with vitamin D levels and blood pressure in patients with EH. Four hundred (200 controls and 200 cases of essential hypertension) participants from general Indian population were enrolled in this study. Peripheral blood samples were collected for genotyping Fok I-VDR gene polymorphism using PCR–RFLP method whereas 25-OH vitamin D levels in serum were quantified using high performance liquid chromatography (HPLC). Significantly reduced 25-OH vitamin D levels were observed in patients with EH (24.04 ± 8.62 vs 50.46 ± 15.46) compared to control subjects (p = 0.0001). Homozygous recessive genotype ‘ff’ frequency was increased by 8.06 fold (CI: 3.71–17.47, p = 0.0001) in patients with EH compared to dominant ‘FF’ genotype frequency. In conclusion, recessive ‘ff’ genotype frequency correlates with reduced serum vitamin D levels and results in significantly increased systolic and diastolic blood pressures leading to predisposition of EH.