Vitamin E supplementation and atherosclerosis : epidemiological studies in elderly and smokers

The antioxidant vitamin E may have beneficial effects on several indicators of human health. We studied the impact on atherosclerosis, immune response and total mortality in smokers and elderly people, who are at risk for increased oxidative stress. Vitamin E may exert its effect on atherosclerosis by protecting low density lipoprotein (LDL) against lipid peroxidation. Moreover, lipid peroxidation may also negatively influence the immune response. In addition to its antioxidant function, vitamin E may be beneficial through effects on cellular function, e.g., by preserving endothelium-dependent vaso-relaxation or decreasing cytokine production.Observational studies . In a cross-sectional study among 158 male lifelong smokers aged 50 to 75 years, adjusted vitamin E intake and plasma levels were not associated with intima media wall thickness (IMT) of the common carotid artery. IMT ,which is a marker for atherosclerosis, was measured non-invasively by using the B-mode ultrasound technique. In a prospective study among 638 independently living elderly aged 65 to 85, no significant association was observed between cholesterol adjusted serum levels of vitamin E and 7.2 years total mortality. (Hazard ratio for lowest tertile vs. highest of 1.11, 95% confidence interval 0.74 to 1.65).Intervention trials. In a randomized placebo-controlled double-blind trial among 218 lifelong male smokers, 400 IU (364 mg) vitamin E was administered daily for two years. A non significant (p=0.34) reduced progression of carotid IMT by 47% was observed compared to a significant spontaneous progression in the placebo group of 0.030 mm (p=0.006). Results were adjusted for initial IMT values and traditional CVD risk factors. Vitamin E significantly reduced the in vitro susceptibility of LDL to oxidation, which was not related to progression.In this trial results were stratified by genetic predisposition. Smokers lacking the detoxifying enzyme activity of glutathion S -transferase µ (genotype GSTM1- 0 ) were compared with those with the positive genotype (GSTM1- 1 ). In the GSTM1- 0 group vitamin E reduced the proportion of smokers with increased carotid IMT by 62% (p=0.06) for the left posterior and by 73% (p=0.01) for the left anterior wall. No effects were observed for the IMT at the right side.In a 3-month randomized double-blind placebo-controlled trial among 83 apparently healthy elderly, aged 67-87 years, 100 mg vitamin E supplementation significantly decreased the percentage of oxidized linoleic acid in LDL (10.4%) compared to the placebo group (4.6%). In this trial vitamin E supplementation did not affect the cellular and humoral immune response.In conclusion , no supportive evidence is provided that vitamin E supplementation has beneficial effects on atherosclerosis and immune response among smokers and elderly. The observations for GSTM1- 0 genotype needs further confirmation. The protective effect of vitamin E on LDL oxidation in vitro lacks validation in vivo. Research on biomarkers of lipid oxidation and arterial damage needs priority to more adequately assess the clinical relevance and optimal intake of vitamin E.</p

Tactility Trialing: Exploring Materials to Inform Tactile Experience Design

Although materials of tangible interaction designs largely determine their user experience, material choices are often steered by practical motives. This paper presents ‘tactility trialing’, an approach to explore tactile experiences of materials to inform the design of tangible artifacts. Through experience formulation, material selection, artifact creation and short user studies, designers and design-researchers are enabled to make informed decisions on the materials to be used in order to evoke the intended experience. The approach is illustrated through two case studies of student work. Tactility trialing helped them in getting acquainted with tactile material qualities in practice, and with the applicability of material characteristics such as resilience and hardness in design

Interaction of bovine blood clotting factor Va and its subunits with phosolipid vesicles

Thrombin-activated factor Va and factor Va subunit binding to large-volume vesicles was investigated by a technique based on the separation by centrifugation of phospholipid-bound protein from the bulk solution. This technique allows the direct measurement of free-protein concentration. It is concluded that the phospholipid binding site on factor Va is located on a basic factor Va subunit with Mr 80 000 (factor Va-LC). The effects of phospholipid vesicle composition, calcium concentration, pH, and ionic strength on the equilibrium constants of factor Va- and factor Va-LC-phospholipid interaction were studied. Factor Va and factor Va-LC binding to phospholipid requires the presence of negatively charged phospholipids. It is further demonstrated that the following occur: (a) Calcium ions compete with factor Va and factor Va-LC for phospholipid-binding sites. (b) The dissociation constant of protein-phospholipid interaction increases with the ionic strength, whereas the maximum protein-binding capacity of the phospholipid vesicle was not affected by ionic strength. (c) The dissociation constant for factor Va-phospholipid interaction depends on pH when the vesicle consists of phosphatidic acid. It is concluded that factor Va-phospholipid interaction is primarily electrostatic in nature, where positively charged groups on the protein directly interact with the phosphate group of net negatively charged phospholipids. The results suggest that factor Va, like factor Xa and prothrombin, has the characteristics of an extrinsic membrane protein

Milieueffecten van Nederlandse consumptie van eiwitrijke producten : gevolgen van vervanging van dierlijke eiwitten anno 2008

In 2008 heeft Blonk Milieu Advies in samenwerking met de vegetariërsbond en het LEI een onderzoek uitgevoerd naar de milieueffecten van een verschuiving van consumptie van dierlijke naar plantaardige eiwitten in de Nederlandse voeding. Daarbij is vooral de focus gelegd op het broeikaseffect en het ruimtebeslag en de mogelijke biodiversiteitseffecten daarvan. Daarnaast is er meer kwalitatief aandacht besteed aan andere effecten zoals dierenwelzijn en de effecten van een consumptiestop van dierlijke producten op de productiekolom van dierlijke producten in Nederlan

Cyber and traditional bullying victimization as a risk factor for mental health problems and suicidal ideation in adolescents

Purpose: To examine whether traditional and cyber bullying victimization were associated with adolescent's mental health problems and suicidal ideation at two-year follow-up. Gender differences were explored to determine whether bullying affects boys and girls differently. Methods: A two-year longitudinal study was conducted among first-year secondary school students (N = 3181). Traditional and cyber bullying victimization were assessed at baseline, whereas mental health status and suicidal ideation were assessed at baseline and follow-up by means of self-report questionnaires. Logistic regression analyses were conducted to assess associations between these variables while controlling for baseline problems. Additionally, we tested whether gender differences in mental health and suicidal ideation were present for the two types of bullying. Results: There was a significant interaction between gender and traditional bullying victimization and between gender and cyber bullying victimization on mental health problems. Among boys, traditional and cyber bullying victimization were not related to mental health problems after controlling for baseline mental health. Among girls, both traditional and cyber bullying victimization were associated with mental health problems after controlling for baseline mental health. No significant interaction between gender and traditional or cyber bullying victimization on suicidal ideation was found. Traditional bullying victimization was associated with suicidal ideation, whereas cyber bullying victimization was not associated with suicidal ideation after controlling for baseline suicidal ideation. Conclusions: Traditional bullying victimization is associated with an increased risk of suicidal ideation, whereas traditional, as well as cyber bullying victimization is associated with an increased risk of mental health problems among girls. These findings stress the importance of programs aimed at reducing bullying behavior, especially because early-onset mental health problems may pose a risk for the development of psychiatric disorders in adulthood