Participation of connexin-based channels in the control of vascular function

SUMMARYIntercellular communication is achieved at specialized regions of the plasma membrane by gap junctions. The proteins constituting the gap junctions are called connexins and are encoded by a family of genes highly conserved during evolution. In adult mouse, four connexins (Cxs) are known to be expressed in the vasculature: Cx37, Cx40, Cx43 and Cx45. Several recent studies have provided evidences that vascular connexins expression and blood pressure regulation are closely linked, suggesting a role for connexins in the control of blood pressure. However, the precise function that each vascular connexin plays under physiological and pathophysiological conditions is still not elucidated. In this context, this work was dedicated to evaluate the contribution of each of the four vascular connexins in the control of the vascular function and in the blood pressure regulation.In the present work, we first demonstrated that vascular connexins are differently regulated by hypertension in the mouse aorta. We also observed that endothelial connexins play a regulatory role on eNOS expression levels and function in the aorta, therefore in the control of vascular tone. Then, we demonstrated that Cx40 plays a pivotal role in the kidney by regulating the renal levels of COX-2 and nNOS, two key enzymes of the macula densa known to participate in the control of renin secreting cells. We also found that Cx43 forms the functional gap junction involved in intercellular Ca2+ wave propagation between vascular smooth muscle cells. Finally, we have started to generate transgenic mice expressing specifically Cx40 in the endothelium to investigate the involvement of Cx40 in the vasomotor tone, or in the renin secreting cells to evaluate the role of Cx40 in the control of renin secretion.In conclusion, this work has allowed us to identify new roles for connexins in the vasculature. Our results suggest that vascular connexins could be interesting targets for new therapies caring hypertension and vascular diseases.

Work and health : remodelling perspectives of working life research, as proposed by Järvholm et al. (2009)

Järvholm and Co-workers (2009) proposed a conceptual model for research on working life. Models are powerful communication and decision tools. This model is strongly unidirectional and does not cover the mentioned interactions in the arguments.With help of a genealogy of work and of health it is shown that work and health are interactive and have to be analysed on the background of society.Key words: research model, work, health, occupational health, society, interaction, discussion paperRemodellierung der von Järvholm et al. (2009) vorgeschlagenen Forschungsperspektiven in Arbeit und GesundheitJärvholm und Kollegen stellten 2009 ein konzeptionelles Modell für die Forschung im Bereich Arbeit und Gesundheit vor. Modelle stellen kraftvolle Kommunikations- und Entscheidungsinstrumente dar. Die Einflussfaktoren im Modell verlaufen jedoch nur in einer Richtung und bilden die interaktiven Argumente im Text nicht ab. Mit Hilfe einer Genealogie der Begriffe Arbeit und Gesundheit wird aufgezeigt, dass Arbeit und Gesundheit sich gegenseitig beeinflussen und nur vor dem Hintergrund der jeweiligen gesellschaftlichen Kontextfaktoren zu analysieren sind.Introduction : After an interesting introduction about the objectives of research on working life, Järvholm and Co-workers (2009) manage to define a conceptual model for working life research out of a small survey of Occupational Safety and Health (OSH) definitions. The strong point of their model is the entity 'working life' including personal development, as well as career paths and aging. Yet, the model Järvholm et al. (2009) propose is strangely unidirectional; the arrows point from the population to working life, from there to health and to disease, as well as to productivity and economic resources. The diagram only shows one feed-back loop: between economic resources and health. We all know that having a chronic disease condition influences work and working capacity. Economic resources have a strong influence on work, too. Having personal economic resources will influence the kind of work someone accepts and facilitate access to continuous professional education. A third observation is that society is not present in the model, although this is less the case in the arguments. In fact, there is an incomprehensible gap between the arguments brought forth by Järvholm and co-workers and their reductionist model.Switzerland has a very low coverage of occupational health specialists. Switzerland is a long way from fulfilling the WHO's recommendations on workers' access to OSH services as described in its Global plan of action. The Institute for Work and Health (IST) in Lausanne is the only organisation which covers the major domains of OSH research that are occupational medicine, occupational hygiene, ergonomic and psychosocial research. As the country's sole occupational health institution we are forced to reflect the objectives of working life research so as not to waste the scare resources available.I will set out below a much shortened genealogy of work and of health, with the aim of extending Järvholm et al's (2009) analyses on the perspectives of working life research in two directions. Firstly towards the interactive nature of work and health and the integration of society, and secondly towards the question of what working life means or where working life could be situated.Work, as we know it today - paid work regulated by a contract as the basis for sustaining life and as a base for social rights - was born in modern era. Therefore I will start my genealogy in the pre-modern era, focus on the important changes that occurred during industrial revolution and the modern era and end in 2010 taking into account the enormous transformations of the past 20-30 years. I will put aside some 810 years of advances in science and technology that have expanded the world's limits and human understanding, and restrict my genealogy to work and to health/body implicating also the societal realm. [Author]

An Integrated Work Force Planning Strategy For The Health Services 2009 - 2012

An Integrated Work Force Planning Strategy For The Health Services 2009 – 2012 Click here to download PDF 1.6mb

Vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide, and noradrenaline induce the transcription factors CCAAT/enhancer binding protein (C/EBP)-beta and C/EBP delta in mouse cortical astrocytes: involvement in cAMP-regulated glycogen metabolism.

We have described previously a transcription-dependent induction of glycogen resynthesis by the vasoactive intestinal peptide (VIP) or noradrenaline (NA) in astrocytes, which is mediated by cAMP. Because it has been postulated that the cAMP-mediated regulation of energy balance in hepatocytes and adipocytes is channeled at least in part through the CCAAT/enhancer binding protein (C/EBP) family of transcription factors, we tested the hypothesis that C/EBP isoforms could be expressed in mouse cortical astrocytes and that their level of expression could be regulated by VIP, by the VIP-related neuropeptide pituitary adenylate cyclase-activating peptide (PACAP), or by NA. We report in this study that in these cells, C/EBP beta and C/EBP delta are induced by VIP, PACAP, or NA via the cAMP second-messenger pathway. Induction of C/EBP beta and -delta mRNA by VIP occurs in the presence of a protein synthesis inhibitor. Thus, c/ebp beta and c/ebp delta behave as cAMP-inducible immediate-early genes in astrocytes. Moreover, transfection of astrocytes with expression vectors selectively producing the transcriptionally active form of C/EBP beta, termed liver-enriched transcriptional activator protein, or C/EBP delta enhance the glycogen resynthesis elicited by NA, whereas an expression vector producing the transcriptionally inactive form of C/EBP beta, termed liver-enriched transcriptional inhibitory protein, reduces this resynthesis. These results support the idea that C/EBP beta and -delta regulate gene expression of energy metabolism-related enzymes in astrocytes.

Characterization of [Ca2+]i responses in primary cultures of mouse cardiomyocytes induced by Trypanosoma cruzi trypomastigotes

Trypanosoma cruzi, the protozoan responsible for Chagas disease, employs distinct strategies to invade mammalian host cells. In the present work we investigated the participation of calcium ions on the invasion process using primary cultures of embryonic mice cardiomyocytes which exhibit spontaneous contraction in vitro. Using Fura 2-AM we found that T. cruzi was able to induce a sustained increase in basal intracellular Ca2+ level in heart muscle cells (HMC), the response being associated or not with Ca2+ transient peaks. Assays performed with both Y and CL strains indicated that the changes in intracellular Ca2+ started after parasites contacted with the cardiomyocytes and the evoked response was higher than the Ca2+ signal associated to the spontaneous contractions. The possible role of the extracellular and intracellular Ca2+ levels on T. cruzi invasion process was evaluated using the extracellular Ca2+ chelator EGTA alone or in association with the calcium ionophore A23187. Significant dose dependent inhibition of the invasion levels were found when intracellular calcium release was prevented by the association of EGTA +A23187 in calcium free medium. Dose response experiments indicated that EGTA 2.5 mM to 5 mM decreased the invasion level by 15.2 to 35.1% while A23187 (0.5 µM) alone did not induce significant effects (17%); treatment of the cultures with the protease inhibitor leupeptin did not affect the endocytic index, thus arguing against the involvement of leupeptin sensitive proteases in the invasion of HMC.

Involvement of environmental mercury and lead in the etiology of neurodegenerative diseases.

The incidence of neurodegenerative disease like Parkinson's disease and Alzheimer's disease (AD) increases dramatically with age; only a small percentage is directly related to familial forms. The etiology of the most abundant, sporadic forms is complex and multifactorial, involving both genetic and environmental factors. Several environmental pollutants have been associated with neurodegenerative disorders. The present article focuses on results obtained in experimental neurotoxicology studies that indicate a potential pathogenic role of lead and mercury in the development of neurodegenerative diseases. Both heavy metals have been shown to interfere with a multitude of intracellular targets, thereby contributing to several pathogenic processes typical of neurodegenerative disorders, including mitochondrial dysfunction, oxidative stress, deregulation of protein turnover, and brain inflammation. Exposure to heavy metals early in development can precondition the brain for developing a neurodegenerative disease later in life. Alternatively, heavy metals can exert their adverse effects through acute neurotoxicity or through slow accumulation during prolonged periods of life. The pro-oxidant effects of heavy metals can exacerbate the age-related increase in oxidative stress that is related to the decline of the antioxidant defense systems. Brain inflammatory reactions also generate oxidative stress. Chronic inflammation can contribute to the formation of the senile plaques that are typical for AD. In accord with this view, nonsteroidal anti-inflammatory drugs and antioxidants suppress early pathogenic processes leading to Alzheimer's disease, thus decreasing the risk of developing the disease. The effects of lead and mercury were also tested in aggregating brain-cell cultures of fetal rat telencephalon, a three-dimensional brain-cell culture system. The continuous application for 10 to 50 days of non-cytotoxic concentrations of heavy metals resulted in their accumulation in brain cells and the occurrence of delayed toxic effects. When applied at non-toxic concentrations, methylmercury, the most common environmental form of mercury, becomes neurotoxic under pro-oxidant conditions. Furthermore, lead and mercury induce glial cell reactivity, a hallmark of brain inflammation. Both mercury and lead increase the expression of the amyloid precursor protein; mercury also stimulates the formation of insoluble beta-amyloid, which plays a crucial role in the pathogenesis of AD and causes oxidative stress and neurotoxicity in vitro. Taken together, a considerable body of evidence suggests that the heavy metals lead and mercury contribute to the etiology of neurodegenerative diseases and emphasizes the importance of taking preventive measures in this regard.

Strategy for personal and public involvement in Health and Social Care research

This report outlines the strategic need for, and benefits of, personal and public involvement to all levels of Health and Social Care Research and Development Division activity.

Promoting physical activity at work: A guide for employers

This booklet is the second in a series of short guides aimed at promoting health in the workplace. It outlines to employers the benefits of promoting physical activity at work, how workplaces can be active places through simple activities and changes, what information and facilities can benefit employees,

Breastfeeding and returning to work

This leaflet aims to encourage breastfeeding mothers to continue breastfeeding after they have returned to work. It highlights the benefits of continuing to breastfeed, sets out the options for combining breastfeeding and work, explains the rights breastfeeding mothers have to support from their employer, and outlines what facilities and equipment mothers will need to express milk at work.

Promoting breastfeeding for mothers returning to work: a guide for employers

This booklet is the third in a series of Work Well guides aimed at promoting health in the workplace. It outlines to employers the business benefits of encouraging mothers to continue breastfeeding on return to work, the health benefits of breastfeeding for mums, the legislation affecting mothers at work, and some easy steps that employers can take to support breastfeeding mothers.

Promoting healthy eating at work: a guide for employers

This booklet is part of the Work Well aimed at promoting health in the workplace. It outlines to employers the benefits of promoting healthy eating at work, what action can be taken, the range of healthier food options that can be provided in a canteen or by using external caterers, ways of promoting healthy eating among employees that do not have to be expensive or time consuming, and key steps for action.

Trypanosoma cruzi: genetic structure of populations and relevance of genetic variability to the pathogenesis of chagas disease

Chagas disease, caused by the protozoan Trypanosoma cruzi, has a variable clinical course, ranging from symptomless infection to severe chronic disease with cardiovascular or gastrointestinal involvement or, occasionally, overwhelming acute episodes. The factors influencing this clinical variability have not been elucidated, but it is likely that the genetic variability of both the host and the parasite are of importance. In this work we review the the genetic structure of T. cruzi populations and analyze the importance of genetic variation of the parasite in the pathogenesis of the disease under the light of the histotropic-clonal model.

A Fitter Future for All - Framework launched

Obesity is a modern lifestyle epidemic that is threatening our health and well-being.This was the key message delivered by Health Minister Edwin Poots at the launch of The Framework for Preventing and Addressing Overweight and Obesity in Northern Ireland 2012-2022: 'A Fitter Future for All'.This ten year strategy will seek to improve the health and wellbeing of people throughout their entire life, from newborns to seniors.Minister Poots said: "We need to face the issue of obesity head on. It's an issue that will require commitment and action from across all sectors, including other government departments and agencies. It is therefore my intention to invest more than £7 million towards tackling the problem of obesity over the next three years."The negative impact on health caused by obesity cannot be over stated. Being obese increases the risk of developing serious illnesses such as heart disease, stroke, some cancers and type 2 diabetes."It is a significant challenge facing modern society and if we don't tackle it now we are storing up a multitude of problems for ourselves in the future."The Minister continued: "More and more of our children and young people are becoming overweight or obese and are putting themselves at risk of developing a range of health problems in their later years."Evidence shows that it is more likely that an obese child will become an obese adult. This in turn will lead to a greater strain on our health and social care services, with more people requiring treatment for obesity related illnesses and specialist care."The proposed framework looks to address a number of key issues, including:-increasing levels of breastfeeding;increasing knowledge and skills about food and its preparationencouraging participation in physical activity;promoting walking and cycling; making sure how we live and where we live encourages and supports healthy eating and physical activity;encouraging and supporting more community involvement with these issues; and;continuation of reformulation of processed foods.The Minister added: "In Northern Ireland 59% of adults are either overweight (36%) or obese (23%). Another worrying statistic is that 8% of children aged 2-15 years were assessed as being obese. These figures demonstrate the scale of the problem and the enormous challenge we are facing."The new framework sets challenging targets. To date we have focussed on simply trying to stop the rise in the levels of obesity, however under A Fitter Future For All we are seeking to actually reduce the level of obesity by 4% and overweight and obesity by 3% among adults. In addition, we are seeking a 3% reduction of obesity and 2% reduction of overweight and obesity among our children and young people." "Meeting these targets will require changes in our lifestyles and behaviours. Most importantly, individuals need to be given the opportunity to make decisions that will benefit their own health and wellbeing".Referring to the 'Give It A Go!' initiative, to increase awareness of the range of nutritional and physical activity initiatives in the southern area, the Minister said: "The Give It A Go! Initiative is a great example of how collaborative work can make such a positive contribution to peoples' lives by providing opportunities for learning, participation in physical activity and for social interaction."Tackling obesity and seeing positive results throughout the life course of the entire population will take time but I strongly believe that the actions set out in this framework will inspire and enable people to improve their diets and be more active."Encouraging people to consider the framework and adopt a healthier lifestyle, the Minister concluded: "Government cannot tackle obesity on its own. We can encourage and promote healthy eating and physical activity but as a society, we must take more individual responsibility for our own health outcomes."Dr Tracy Owen, Consultant in Public Health Medicine with the PHA, said: "The PHA is already working with partner organisations across many of the areas included in the framework 'A Fitter Future for All' and is addressing issues such as developing people's skills and knowledge about healthier eating along with encouraging participation in physical activity. The framework gives us the opportunity to raise awareness of this important area and strengthen action."As the Minister has mentioned, a good example of this coordinated action is the PHA supported initiative Give it a Go! which is providing people in the Southern area with the opportunity to learn about food through supermarket tours and Cook it! classes and to get active through walks, spinning classes and many other activities, all of which are free. These taster sessions are aimed at raising awareness of healthier lifestyles which will ultimately make changes in behaviour more likely."These changes, no matter how small, can help people to lose weight, maintain a healthy weight and bring big benefits to their general health. Importantly, we have developed this joint programme by working closely with our partners, particularly local councils."

Leishmania braziliensis: partial control of experimental infection by interleukin-12 p40 deficient mice

Resistance to infection by Leishmania major has been associated with the development of a Th1 type response that is dependent on the presence of interleukin 12 (IL-12). In this work the involvement of this cytokine in the response to infection by L. braziliensis, a less virulent species in the mouse model, was evaluated. Our results show that while interferon (IFN-g) deficient (-/-) mice inoculated L. braziliensis develop severe uncontrolled lesions, chronic lesions that remained under control up to 12 weeks of infection were observed in IL-12p40 -/- mice. IL 12p40 -/- mice had fewer parasites in their lesions than IFN-g-/- mice. Lymph node cells from IL-12p40 -/- were capable of producing low but consistent levels of IFN-g suggestive of its involvement in parasite control. Furthermore, as opposed to previous reports on L. major-infected animals, no switch to a Th2 response was observed in IL-12p40 -/- infected with L. braziliensis.