Effects of contractile protein phosphorylation on force development in permeabilized rat cardiac myocytes

The phosphorylation status of myofibrillar proteins influences the Ca2+ responsiveness of the myofilaments,but the contribution of and the interaction between the individual components is poorly characterized. Therefore, in Langendorff perfused rat hearts (n=30), the phosphorylation levels of cardiac myosin binding protein-C (cMyBP-C), troponin I and T (cTnI, cTnT) and myosin light chain 1 and 2 (MLC-1, MLC-2) were determined by 1- and 2-dimensional gel electrophoresis. Isometric force development, its Ca2+-sensitivity, the rate of tension redevelopment (ktr) and passive force (Fpas) were studied at optimal sarcomere length (2.2 μm) in mechanically isolated,permeabilized cardiomyocytes at 15 °C. Protein phosphorylation was varied by: 1) blocking spontaneous cardiac activity by lidocaine (0.35 mM; Quiescence); 2) electrical stimulation of the hearts at 5 Hz (Contraction) and 3. treatment of contracting hearts with Isoprenaline (1 μM). MLC-2 phosphorylation was increased in the Contraction group almost 2-fold, relative to the Quiescence group, whereas cMyBP-C and cTnI phosphorylation remained the same. Isoprenaline resulted in 3.7-fold increases in both cMyBP-C and cTnI phosphorylation, but did not result in a further increase in MLC-2 phosphorylation.No significant differences were found in maximum force and ktr between groups, both before and after protein kinase A (PKA) treatment. Ca2+-sensitivity in the Contraction and Isoprenaline groups was significantly reduced in comparison to the Quiescence group. These differences were largely abolished by PKA and Fpas was reduced. These results highlight the impact of PKA-dependent phosphorylation on Ca2+-sensitivity and provide evidence for an interaction between the effects of TnI and MLC-2 phosphorylation

Politiestress:feiten en mythes

Politieagenten worden veelvuldig blootgesteld aan allerhande ingrijpende situaties. Stressklachten worden daaraan toegeschreven. Maar is dat juist? Wat is er bekend aan onderzoek naar de invloed van schokkende gebeurtenissen op stressklachten? En hoe stressvol is het politievak in verhouding tot andere beroepen? Een verslag van diverse studies uit binnen- en buitenland met opvallende conclusies

The Short-term Influence of a Mediterranean-type Diet and Mild Exercise with and without Red Wine on Patients with the Metabolic Syndrome

The metabolic syndrome is a target for the dietary prevention of cardiovascular disease. The effect of adding redwine to the diet has not been fully investigated. This study examined whether a Mediterranean-type dietcomplemented with red wine and mild exercise had an impact on patients with the metabolic syndrome in the shortterm. Twelve patients with the metabolic syndrome consumed a Mediterranean-type diet for four weeks withoutand with red wine respectively and performed mild exercise. We implemented the diagnostic criteria for themetabolic syndrome as formulated by the Adult Treatment Panel III (ATP III) in 2001. The patients were alsoscreened for multiple genetic markers implicated in cardiovascular disease. Weight, body mass index, abdominalcircumference and blood pressure were measured, as well as various biochemical, haematological andinflammatory markers. There was a significant decrease in the body weight (p = 0.04) and an increase in ORACvalue (p = 0.035) after the dietary intervention. A significant decrease in systolic blood pressure (p = 0.045) wasobserved. Red wine had no additional benefits. Although diet reduced weight and blood pressure, the lipoproteinand pro-coagulant profiles of patients with the metabolic syndrome were not affected in this study. These findingsmay be explained partly by the diverse genetic profile identified among the study participants, as 50% hadmutations involved in lipid metabolism that may influence the response to dietary intervention and alcoholconsumption

Ethics and practice of trials within cohorts: An emerging pragmatic trial design

BACKGROUND: With increasing emphasis on pragmatic trials, new randomized clinical trial designs are being proposed to enhance the "real world" nature of the data generated. We describe one such design, appropriate for unmasked pragmatic clinical trials in which the control arm receives usual care, called "Trials within Cohorts" that is increasingly used in various countries because of its efficiency in recruitment, advantages in reducing subject burden, and ability to better mimic real-world consent processes. METHODS: Descriptive, ethical, and US regulatory analysis of the Trials within Cohorts design. RESULTS: Trials within Cohorts design involves, after recruitment into a cohort, randomization of eligible subjects, followed by an asymmetric treatment of the two arms: those selected for the experimental arm provide informed consent for the intervention trial, while the data from the control arm are used based on prior broad permission. Thus, unlike the traditional Zelen post-randomization consent design, the cohort participants are informed about future research within the cohort; however, the extent of this disclosure currently varies among studies. Thus, ethical analysis is provided for two types of situations: when the pre-randomization disclosure and consent regarding the embedded trials are fairly explicit and detailed versus when they consist of only general statements about future data use. These differing ethical situations could have implications for how ethics review committees apply US research rules regarding waivers and alterations of informed consent. CONCLUSION: Trials within Cohorts is a promising new pragmatic randomized controlled trial design that is being increasingly used in various countries. Although the asymmetric consent procedures for the experimental versus control arm subjects can initially raise ethical concerns, it is ethically superior to previous post-randomization consent designs and can have important advantages over traditional trial designs