119 research outputs found

    Muscarinic cholinergic stimulation of phosphatidylinositol turnover in the longitudinal smooth muscle of guinea-pig ileum

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    1. The metabolism of phosphatidylinositol and phosphatidate was investigated in fragments of longitudinal smooth muscle from guinea-pig ileum incubated with cholinergic and anticholinergic drugs. 2. Incorporation of Pi into these lipids was enhanced by acetylcholine and carbamoylcholine. 3. The receptor responsible for triggering this response was of the muscarinic type, since (a) the response was also produced by the muscarinic agonists acetyl-beta-methylcholine, carbamoyl-beta-methylcholine and pilocarpine, and (b) the response was prevented by atropine and prophylbenzilylcholine mustard, but not by tubocurarine. 4. Increased phosphatidylinositol labellin was clearly observed within 5 min in tissue treated with a high concentration of carbamoylcholine. 5. Halfmaximal stimulation of phosphatidylinositol labelling occurred at approx. 10 muM-muM-carbamoylcholine. 6. Incubation of muscle fragments with carbamoylcholine provoked a decrease in phosphatidylinositol concentration, as would be expected if phosphatidyl-inositol breakdown is the reaction controlled by agonists. 7. This information all appears consistent with the proposal that phosphatidylinositol breakdown may be a reaction intrinsic to the mechanisms of muscarinic cholinergic receptor systems

    Flecainide exerts paradoxical effects on sodium currents and atrial arrhythmia in murine RyR2-P2328S hearts.

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    AIMS: Cardiac ryanodine receptor mutations are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT), and some, including RyR2-P2328S, also predispose to atrial fibrillation. Recent work associates reduced atrial Nav 1.5 currents in homozygous RyR2-P2328S (RyR2(S/S) ) mice with slowed conduction and increased arrhythmogenicity. Yet clinically, and in murine models, the Nav 1.5 blocker flecainide reduces ventricular arrhythmogenicity in CPVT. We aimed to determine whether, and how, flecainide influences atrial arrhythmogenicity in RyR2(S/S) mice and their wild-type (WT) littermates. METHODS: We explored effects of 1 μm flecainide on WT and RyR2(S/S) atria. Arrhythmic incidence, action potential (AP) conduction velocity (CV), atrial effective refractory period (AERP) and AP wavelength (λ = CV × AERP) were measured using multi-electrode array recordings in Langendorff-perfused hearts; Na(+) currents (INa ) were recorded using loose patch clamping of superfused atria. RESULTS: RyR2(S/S) showed more frequent atrial arrhythmias, slower CV, reduced INa and unchanged AERP compared to WT. Flecainide was anti-arrhythmic in RyR2(S/S) but pro-arrhythmic in WT. It increased INa in RyR2(S/S) atria, whereas it reduced INa as expected in WT. It increased AERP while sparing CV in RyR2(S/S) , but reduced CV while sparing AERP in WT. Thus, RyR2(S/S) hearts have low λ relative to WT; flecainide then increases λ in RyR2(S/S) but decreases λ in WT. CONCLUSIONS: Flecainide (1 μm) rescues the RyR2-P2328S atrial arrhythmogenic phenotype by restoring compromised INa and λ, changes recently attributed to increased sarcoplasmic reticular Ca(2+) release. This contrasts with the increased arrhythmic incidence and reduced INa and λ with flecainide in WT.This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC, UK) under a David Phillips Fellowship held by JAF (BB/FO23863/1) and by the Isaac Newton Trust/Wellcome Trust ISSF/University of Cambridge Joint Research Grants Scheme.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/apha.1250

    Factors Identified by Lapsed Donors that Might Influence Donor Return

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    Introduction: The Burlington Chapter of the American Red Cross estimates that 8,000 donors a year become lapsed, or fail to return for further donation. To better target this population and retain current donors, it is essential to identify reasons for lapsed donation. Several studies have been conducted on the barriers to retaining blood donors, revealing these common factors: past physical reactions, convenience, previous deferrals, lack of awareness, medical reasons, time, satisfaction with the experience, too impersonal, and personal benefit. While many studies have identified reasons for lapsed donation, the majority have not used free text as their data source, have been conducted in a wide range of geographic locations not specific to Vermont residents, and have focused on reasons for discontinuing donations, rather than positive factors. Using free text limits the question bias and eliminates constraints that predefined answers enforce. In 2007, Balderama et alconducted a study identifying common motivations for donating blood, which included an unanalyzed free text portion. We used this free text to answer the question, “What factors identified by lapsed donors might influence donor return?”https://scholarworks.uvm.edu/comphp_gallery/1047/thumbnail.jp

    NKG2D ligand tumor expression and association with clinical outcome in early breast cancer patients: an observational study.

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    BACKGROUND: Cell surface NKG2D ligands (NKG2DL) bind to the activating NKG2D receptor present on NK cells and subsets of T cells, thus playing a role in initiating an immune response. We examined tumor expression and prognostic effect of NKG2DL in breast cancer patients. METHODS: Our study population (n = 677) consisted of all breast cancer patients primarily treated with surgery in our center between 1985 and 1994. Formalin-fixed paraffin-embedded tumor tissue was immunohistochemically stained with antibodies directed against MIC-A/MIC-B (MIC-AB), ULBP-1, ULBP-2, ULBP-3, ULBP-4, and ULBP-5. RESULTS: NKG2DL were frequently expressed by tumors (MIC-AB, 50% of the cases; ULBP-1, 90%; ULBP-2, 99%; ULBP-3, 100%; ULBP-4, 26%; ULBP-5, 90%) and often showed co-expression: MIC-AB and ULBP-4 (p = 0.043), ULBP-1 and ULBP-5 (p = 0.006), ULBP-4 and ULBP-5 (p < 0.001). MIC-AB (p = 0.001) and ULBP-2 (p = 0.006) expression resulted in a statistically significant longer relapse free period (RFP). Combined expression of these ligands showed to be an independent prognostic parameter for RFP (p < 0.001, HR 0.41). Combined expression of all ligands showed no associations with clinical outcome. CONCLUSIONS: We demonstrated for the first time that NKG2DL are frequently expressed and often co-expressed in breast cancer. Expression of MIC-AB and ULBP-2 resulted in a statistically significant beneficial outcome concerning RFP with high discriminative power. Combination of all NKG2DL showed no additive or interactive effect of ligands on each other, suggesting that similar and co-operative functioning of all NKG2DL can not be assumed. Our observations suggest that among driving forces in breast cancer outcome are immune activation on one site and tumor immune escape on the other site.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Cellular expression, trafficking, and function of two isoforms of human ULBP5/RAET1G

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    Background: The activating immunoreceptor NKG2D is expressed on Natural Killer (NK) cells and subsets of T cells. NKG2D contributes to anti-tumour and anti-viral immune responses in vitro and in vivo. The ligands for NKG2D in humans are diverse proteins of the MIC and ULBP/RAET families that are upregulated on the surface of virally infected cells and tumours. Two splicing variants of ULBP5/RAET1G have been cloned previously, but not extensively characterised. Methodology/Principal Findings: We pursue a number of approaches to characterise the expression, trafficking, and function of the two isoforms of ULBP5/RAET1G. We show that both transcripts are frequently expressed in cell lines derived from epithelial cancers, and in primary breast cancers. The full-length transcript, RAET1G1, is predicted to encode a molecule with transmembrane and cytoplasmic domains that are unique amongst NKG2D ligands. Using specific anti-RAET1G1 antiserum to stain tissue microarrays we show that RAET1G1 expression is highly restricted in normal tissues. RAET1G1 was expressed at a low level in normal gastrointestinal epithelial cells in a similar pattern to MICA. Both RAET1G1 and MICA showed increased expression in the gut of patients with celiac disease. In contrast to healthy tissues the RAET1G1 antiserum stained a wide variety or different primary tumour sections. Both endogenously expressed and transfected RAET1G1 was mainly found inside the cell, with a minority of the protein reaching the cell surface. Conversely the truncated splicing variant of RAET1G2 was shown to encode a soluble molecule that could be secreted from cells. Secreted RAET1G2 was shown to downregulate NKG2D receptor expression on NK cells and hence may represent a novel tumour immune evasion strategy. Conclusions/Significance: We demonstrate that the expression patterns of ULBP5RAET1G are very similar to the well-characterised NKG2D ligand, MICA. However the two isoforms of ULBP5/RAET1G have very different cellular localisations that are likely to reflect unique functionality

    Contemporary review of risk-stratified management in acute uncomplicated and complicated diverticulitis

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    BACKGROUND: Acute colonic diverticulitis is a common clinical condition. Severity of the disease is based on clinical, laboratory, and radiological investigations and dictates the need for medical or surgical intervention. Recent clinical trials have improved the understanding of the natural history of the disease resulting in new approaches to and better evidence for the management of acute diverticulitis. METHODS: We searched the Cochrane Library (years 2004-2015), MEDLINE (years 2004-2015), and EMBASE (years 2004-2015) databases. We used the search terms "diverticulitis, colonic" or "acute diverticulitis" or "divertic*" in combination with the terms "management," "antibiotics," "non-operative," or "surgery." Registers for clinical trials (such as the WHO registry and the https://clinicaltrials.gov/) were searched for ongoing, recruiting, or closed trials not yet published. RESULTS: Antibiotic treatment can be avoided in simple, non-complicated diverticulitis and outpatient management is safe. The management of complicated disease, ranging from a localized abscess to perforation with diffuse peritonitis, has changed towards either percutaneous or minimally invasive approaches in selected cases. The role of laparoscopic lavage without resection in perforated non-fecal diverticulitis is still debated; however, recent evidence from two randomised controlled trials has found a higher re-intervention in this group of patients. CONCLUSIONS: A shift in management has occurred towards conservative management in acute uncomplicated disease. Those with uncomplicated acute diverticulitis may be treated without antibiotics. For complicated diverticulitis with purulent peritonitis, the use of peritoneal lavage appears to be non-superior to resection

    Nitrite Biosensing via Selective Enzymes—A Long but Promising Route

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    The last decades have witnessed a steady increase of the social and political awareness for the need of monitoring and controlling environmental and industrial processes. In the case of nitrite ion, due to its potential toxicity for human health, the European Union has recently implemented a number of rules to restrict its level in drinking waters and food products. Although several analytical protocols have been proposed for nitrite quantification, none of them enable a reliable and quick analysis of complex samples. An alternative approach relies on the construction of biosensing devices using stable enzymes, with both high activity and specificity for nitrite. In this paper we review the current state-of-the-art in the field of electrochemical and optical biosensors using nitrite reducing enzymes as biorecognition elements and discuss the opportunities and challenges in this emerging market

    Worcester Area Writers

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    The goal of the Worcester Area Writers project was to learn more about local writers who have a connection to Worcester, MA and make available to the World Wide Web selected interviews and critical biographical information. I approached this project by analyzing several pieces from various authors/writers from the Worcester area and found the works of Mary Bonina and Eve Rifkah compelling and fascinating. I conducted a videotaped interview of both authors detailing their life and their literary works. By thoroughly reading many works of these writers, organizing information from the interview, and by carrying out additional research, I was able to write a critical biography of both authors. The biography and video interview were then uploaded on the Worcester Area Writers webpage

    Incorporating cinnamaldehyde into concrete for corrosion mitigation

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    Concrete structures can prematurely deteriorate due to the corrosion of reinforcing steel. Corrosion can occur through chloride ingress due to exposure to aggressive media such as seawater and deicing salts. Corrosion causes over $100 billion in damage annually. There are many corrosion mitigation techniques on the market today; these techniques have limited effectiveness as demonstrated by the fact that billions of dollars are still being expended each year due to corrosion-related damage. Therefore, there is a need for innovative approaches to corrosion prevention. This research program used cinnamaldehyde (CA), a bioactive agent derived from cinnamon bark, as a method for corrosion mitigation. Although CA can prevent the corrosion of metals, its hydrophobicity has a negative effect on hydration when incorporated in cementitious systems. In order to avoid these negative consequences while harnessing the anti-corrosive properties, CA was incorporated in a cementitious mixture through the use of lightweight aggregate (LWA). Several tests were carried out to investigate the potential chemical and mechanical effects due to the addition of LWA pre-wet with CA. Promising results were observed, in which the time to corrosion was prolonged by 91 %

    Stem Cells and Society

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    The issue of stem cells is highly debated and controversial. Although growing research continues to promise new hope for those suffering with diseases, stem cells continue to spur ethical concerns because of their controversial source. My analysis discusses the effect of this controversial technology on society. Furthermore, my analysis emphasizes the two distinct types of stem cells, adult stem cells and ES cells which have different moral and legal statuses. In terms of ethics, all major religions allow adult stem cell research. But the ethics of ES cells is scattered, some religions opposing and others supporting them. In terms of policies, the United States has taken a restrictive approach towards ES cell research, whereas many other nations have embraced adult and ES cell research
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