94 research outputs found
Perivascular Adipose Tissue Diminishes Nitric Oxide Bioavailability in Metabolic Syndrome
Please refer to the pdf version of the abstract located adjacent to the title
The VHITAL Program to Demonstrate the Performance and Lifetime of a Bismuth-Fueled Very High Isp Hall Thruster
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76921/1/AIAA-2005-4564-316.pd
Inverse association of colorectal cancer prevalence to serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in a large Appalachian population
Background
Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent environmental contaminants that affect metabolic regulation, inflammation, and other factors implicated in the development and progression of colorectal cancer (CRC). However, the link between these compounds and CRC remains unknown. In this cross-sectional study, we investigated the association of CRC diagnosis to PFOA and PFOS blood levels in a large Appalachian population. Methods
Participants were 47,359 adultsโโฅโ21 years of age and residing in six PFOA-contaminated water districts in the mid-Ohio Valley (Nโ=โ47,151 cancer-free adults, 208 cases of primary CRC). All participants completed a comprehensive health survey between 2005 and 2006; serum levels of PFOA, PFOS, and a range of other blood markers were also measured. Medical history was assessed via self report and cancer diagnosis confirmed via chart review. Results
CRC showed a strong inverse, doseโresponse association with PFOS serum levels (odds ratio (OR) adjusted for potential confoundersโ=โ0.2, 95% confidence interval (CI) 0.2,0.3) for highest vs. lowest quartile of PFOS, P-trendโ\u3cโ0.00001) and a significant, but more modest inverse association with PFOA (adjusted ORโ=โ0.6 (CI 0.4, 0.9) for highest vs. lowest quartile, P-trendโ=โ0.001). These inverse associations were stronger in those diagnosed within the previous 6 years and resident in the same water district for a minimum of 10โ15 years preceding assessment. The relationship between PFOA and CRC was also more pronounced in men and leaner adults, and showed a stronger linear trend at lower exposure levels. Conclusions
In this large cross-sectional study, we found a strong, inverse association between PFOS and likelihood of CRC diagnosis and a significant, although more modest inverse association between PFOA and CRC. If confirmed in prospective investigations, these findings may aid in identifying new strategies for CRC prevention and treatment and inform future studies regarding mechanisms underlying CRC pathogenesis
Diet-Induced Obesity Impairs Endothelium-Derived Hyperpolarization via Altered Potassium Channel Signaling Mechanisms
BACKGROUND: The vascular endothelium plays a critical role in the control of blood flow. Altered endothelium-mediated vasodilator and vasoconstrictor mechanisms underlie key aspects of cardiovascular disease, including those in obesity. Whilst the mechanism of nitric oxide (NO)-mediated vasodilation has been extensively studied in obesity, little is known about the impact of obesity on vasodilation to the endothelium-derived hyperpolarization (EDH) mechanism; which predominates in smaller resistance vessels and is characterized in this study. METHODOLOGY/PRINCIPAL FINDINGS: Membrane potential, vessel diameter and luminal pressure were recorded in 4(th) order mesenteric arteries with pressure-induced myogenic tone, in control and diet-induced obese rats. Obesity, reflecting that of human dietary etiology, was induced with a cafeteria-style diet (โผ30 kJ, fat) over 16-20 weeks. Age and sexed matched controls received standard chow (โผ12 kJ, fat). Channel protein distribution, expression and vessel morphology were determined using immunohistochemistry, Western blotting and ultrastructural techniques. In control and obese rat vessels, acetylcholine-mediated EDH was abolished by small and intermediate conductance calcium-activated potassium channel (SK(Ca)/IK(Ca)) inhibition; with such activity being impaired in obesity. SK(Ca)-IK(Ca) activation with cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA) and 1-ethyl-2-benzimidazolinone (1-EBIO), respectively, hyperpolarized and relaxed vessels from control and obese rats. IK(Ca)-mediated EDH contribution was increased in obesity, and associated with altered IK(Ca) distribution and elevated expression. In contrast, the SK(Ca)-dependent-EDH component was reduced in obesity. Inward-rectifying potassium channel (K(ir)) and Na(+)/K(+)-ATPase inhibition by barium/ouabain, respectively, attenuated and abolished EDH in arteries from control and obese rats, respectively; reflecting differential K(ir) expression and distribution. Although changes in medial properties occurred, obesity had no effect on myoendothelial gap junction density. CONCLUSION/SIGNIFICANCE: In obese rats, vasodilation to EDH is impaired due to changes in the underlying potassium channel signaling mechanisms. Whilst myoendothelial gap junction density is unchanged in arteries of obese compared to control, increased IK(Ca) and Na(+)/K(+)-ATPase, and decreased K(ir) underlie changes in the EDH mechanism
Moderate hyperoxic versus near-physiological oxygen targets during and after coronary artery bypass surgery: a randomised controlled trial
Local Oxidative and Nitrosative Stress Increases in the Microcirculation during Leukocytes-Endothelial Cell Interactions
Leukocyte-endothelial cell interactions and leukocyte activation are important factors for vascular diseases including nephropathy, retinopathy and angiopathy. In addition, endothelial cell dysfunction is reported in vascular disease condition. Endothelial dysfunction is characterized by increased superoxide (O2โขโ) production from endothelium and reduction in NO bioavailability. Experimental studies have suggested a possible role for leukocyte-endothelial cell interaction in the vessel NO and peroxynitrite levels and their role in vascular disorders in the arterial side of microcirculation. However, anti-adhesion therapies for preventing leukocyte-endothelial cell interaction related vascular disorders showed limited success. The endothelial dysfunction related changes in vessel NO and peroxynitrite levels, leukocyte-endothelial cell interaction and leukocyte activation are not completely understood in vascular disorders. The objective of this study was to investigate the role of endothelial dysfunction extent, leukocyte-endothelial interaction, leukocyte activation and superoxide dismutase therapy on the transport and interactions of NO, O2โขโ and peroxynitrite in the microcirculation. We developed a biotransport model of NO, O2โขโ and peroxynitrite in the arteriolar microcirculation and incorporated leukocytes-endothelial cell interactions. The concentration profiles of NO, O2โขโ and peroxynitrite within blood vessel and leukocytes are presented at multiple levels of endothelial oxidative stress with leukocyte activation and increased superoxide dismutase accounted for in certain cases. The results showed that the maximum concentrations of NO decreased โผ0.6 fold, O2โขโ increased โผ27 fold and peroxynitrite increased โผ30 fold in the endothelial and smooth muscle region in severe oxidative stress condition as compared to that of normal physiologic conditions. The results show that the onset of endothelial oxidative stress can cause an increase in O2โขโ and peroxynitrite concentration in the lumen. The increased O2โขโ and peroxynitrite can cause leukocytes priming through peroxynitrite and leukocytes activation through secondary stimuli of O2โขโ in bloodstream without endothelial interaction. This finding supports that leukocyte rolling/adhesion and activation are independent events
Body mass index and dental caries in children and adolescents : a systematic review of literature published 2004 to 2011
The objectiveThe authors undertook an updated systematic review of the relationship between body mass index and dental caries in children and adolescents.MethodThe authors searched Medline, ISI, Cochrane, Scopus, Global Health and CINAHL databases and conducted lateral searches from reference lists for papers published from 2004 to 2011, inclusive. All empirical papers that tested associations between body mass index and dental caries in child and adolescent populations (aged 0 to 18 years) were included.ResultsDental caries is associated with both high and low body mass index.ConclusionA non-linear association between body mass index and dental caries may account for inconsistent findings in previous research. We recommend future research investigate the nature of the association between body mass index and dental caries in samples that include a full range of body mass index scores, and explore how factors such as socioeconomic status mediate the association between body mass index and dental caries.<br /
Course of serum amyloid A (SAA) plasma concentrations in horses undergoing surgery for injuries penetrating synovial structures, an observational clinical study
Abstract Background Injuries penetrating synovial structures are common in equine practice and often result in septic synovitis. Significantly increased plasma levels of serum amyloid A (SAA) have been found in various infectious conditions in horses including wounds and septic arthritis. Plasma SAA levels were found to decrease rapidly once the infectious stimulus was eliminated. The purpose of the current study was to investigate the usefulness of serial measurements of plasma SAA as a monitoring tool for the response to treatment of horses presented with injuries penetrating synovial structures. In the current study plasma SAA concentrations were measured every 48 hours (h) during the course of treatment. Results A total of 19 horses with a wound penetrating a synovial structure were included in the current study. Horses in Group 1 (nย =ย 12) (injuries older than 24ย h) only needed one surgical intervention. Patients in this group had significantly lower median plasma SAA levels (Pย =ย 0.001) between 48ย h (median 776ย mg/L) and 96ย h (median 202ย mg/L) after surgery. A significant decrease (Pย =ย 0.004) in plasma SAA levels was also observed between 96ย h after surgery (median 270ย mg/L) and 6ย days (d) after surgery (median 3ย mg/L). Four horses (Group 2) required more than one surgical intervention. In contrast to Group 1 patients in Group 2ย had either very high initial plasma concentrations (3378ย mg/L), an increase or persistently high concentrations of plasma SAA after the first surgery (median 2525ย mg/L). A small group of patients (nย =ย 3) (Group 3) were admitted less than 24ย h after sustaining a wound. In this group low SAA values at admission (median 23ย mg/L) and peak concentrations at 48ย h after surgery (median 1016ย mg/L) were observed followed by a decrease in plasma SAA concentration over time. Conclusions A decrease in plasma SAA concentrations between two consecutive time points could be associated with positive response to treatment in the current study. Therefore, serial measurements of plasma SAA could potentially be used as an additional inexpensive, quick and easy tool for monitoring the treatment response in otherwise healthy horses presented with injuries penetrating synovial structures. However further studies will be necessary to ascertain its clinical utility
Inverse association of colorectal cancer prevalence to serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in a large Appalachian population
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