tbuckley/cabot-search huggingface dataset:
Adenovirus-Based Strategies Overcome Temozolomide Resistance by Silencing the O6-Methylguanine-DNA Methyltransferase Promoter
Authors: Marta M. Alonso, Candelaria Gomez-Manzano, B. Nebiyou Bekele, W.K. Alfred Yung, Juan Fueyo
Journal: Cancer Research (2007)

Abstract Currently, the most efficacious treatment for malignant gliomas is temozolomide; however, gliomas expressing the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) are resistant to this drug. Strong clinical evidence shows that gliomas with methylation and subsequent silencing of the MGMT promoter are sensitive to temozolomide. Based on the fact that adenoviral proteins directly target and inactivate key DNA repair genes, we hypothesized that the oncolytic adenovirus Δ-24-RGD could be successfully combined with temozolomide to overcome the reported MGMT-mediated resistance. Our studies showed that the combination of Δ-24-RGD and temozolomide induces a profound therapeutic synergy in glioma cells. We observed that Δ-24-RGD treatment overrides the temozolomide-mediated G2-M arrest. Furthermore, Δ-24-RGD infection was followed by down-modulation of the RNA levels of MGMT. Chromatin immunoprecipitation assays showed that Δ-24-RGD prevented the recruitment of p300 to the MGMT promoter. Importantly, using mutant adenoviruses and wild-type and dominant-negative forms of the p300 protein, we showed that Δ-24-RGD interaction with p300 was required to induce silencing of the MGMT gene. Of further clinical relevance, the combination of Δ-24-RGD and temozolomide significantly improved the survival of glioma-bearing mice. Collectively, our data provide a strong mechanistic rationale for the combination of oncolytic adenoviruses and temozolomide, and should propel the clinical testing of this therapy approach in patients with malignant gliomas. [Cancer Res 2007;67(24):11499–504]
Inhibition of Protein Kinase Cβ Prevents Foam Cell Formation by Reducing Scavenger Receptor A Expression in Human Macrophages
Authors: Elena Osto, Alexei Kouroedov, Pavani Mocharla, Alexander Akhmedov, Christian Besler, Lucia Rohrer, Arnold von Eckardstein, Sabino Iliceto, Massimo Volpe, Thomas F. Lüscher, Francesco Cosentino
Journal: Circulation (2008)

Low-density lipoprotein (LDL) uptake by monocyte-derived macrophages is a crucial step in foam cell formation and early atherosclerotic lesion. Increasing evidence supports the theory that activation of protein kinase Cbeta (PKCbeta) is involved in many mechanisms promoting atherosclerosis. Thus, we investigated whether inhibition of PKCbeta prevents foam cell formation.The differentiation of human primary monocytes or the monocytic THP-1 cell line into monocyte-derived macrophages was induced by phorbol 12-myristate 13-acetate (PMA; 0.1 mmol/L), a potent activator of PKC. Incubation of monocyte-derived macrophages with DiI-modified LDL (acetylated LDL and oxidized LDL, 10 mug/mL) led to lipoprotein uptake. Interestingly enough, the nonselective inhibitor of PKCbeta(1) and PKCbeta(2), LY379196 (5x10(-7) to 10(-5) mol/L), blunted LDL uptake in monocyte-derived macrophages as shown by flow cytometry. Specific siRNA-mediated knockdown of PKCbeta exerted a similar effect. Furthermore, PMA alone and in the presence of modified LDL induced scavenger receptor A mRNA and protein expression, which was abolished by LY379196. CGP53353, a selective inhibitor of PKCbeta(2), did not affect LDL uptake, nor did it prevent scavenger receptor A upregulation. Incubation of monocyte-derived macrophages with PMA/LDL increased PKCbeta(1) phosphorylation at the Thr-642 residue, which was blunted by LY379196. However, the expression of CD68, a marker of activated macrophages, was not affected by LY379196. Moreover, LY379196 did not affect lipopolysaccharide-induced CD14 degradation, tumor necrosis factor-alpha release, or superoxide anion production, ruling out any effect of PKCbeta inhibition on innate immunity.Nonspecific inhibition of PKCbeta prevents LDL uptake in macrophages. These findings suggest that PKCbeta inhibitors may represent a novel class of antiatherosclerotic drugs.
Myocardial Lineage Development
Authors: Sylvia M. Evans, Deborah Yelon, Frank L. Conlon, Margaret L. Kirby
Journal: Circulation Research (2010)

The myocardium of the heart is composed of multiple highly specialized myocardial lineages, including those of the ventricular and atrial myocardium, and the specialized conduction system. Specification and maturation of each of these lineages during heart development is a highly ordered, ongoing process involving multiple signaling pathways and their intersection with transcriptional regulatory networks. Here, we attempt to summarize and compare much of what we know about specification and maturation of myocardial lineages from studies in several different vertebrate model systems. To date, most research has focused on early specification, and although there is still more to learn about early specification, less is known about factors that promote subsequent maturation of myocardial lineages required to build the functioning adult heart.
Regional expression of phospholamban in the human heart
Authors: Peter Bokník, Claus Unkel, Uwe Kirchhefer, Ulrich Kleideiter, Oliver Klein-Wiele, Jörg Knapp, Bettina Linck, Hartmut Lüss, Frank Ulrich Müller, Wilhelm Schmitz, Ute Vahlensieck, Norbert Zimmermann, Larry R. Jones, Joachim Neumann
Journal: Cardiovascular Research (1999)

Background: Several independent lines of evidence indicate that phospholamban (PLB) expression correlates positively with depression of force of contraction and duration of contraction in isolated cardiac preparations of several animal species. Here, we studied whether PLB levels correlate with attenuation of contractility and enhancement of contractile time parameters in different parts of the human heart. Methods: Force of contraction was measured in isolated electrically driven atrial and ventricular preparations from human hearts. Ca2+-uptake by human atrial and ventricular homogenates was assayed at different ionized Ca2+-concentrations. Protein expression of PLB and the sarcoplasmic Ca2+-ATPase (SERCA) was measured in homogenates by quantitative immunoblotting using specific antibodies. PLB mRNA expression was quantified in human cardiac preparations by Northern blot analysis. Results: The duration of contraction in isolated preparations of human right ventricle (RV) was double that found in right atrial preparations (RA) (620±25 ms versus 308±15 ms). In RA, PLB expression was reduced by 44% at the protein level and by 34% at the mRNA level compared to RV. In contrast, the SERCA protein content was increased by 104% in RA compared to RV. Ca2+-uptake at low ionized Ca2+-concentration, where the inhibiting effect of PLB is maximal, amounted to 1.39±0.28 nmol Ca2+/mg protein in RA and to 0.62±0.09 nmol Ca2+/mg protein in RV (n=6 both). Conclusions: It is suggested that duration of contraction is shorter in human atrium versus ventricle due to the combined effect of decreased PLB levels (which inhibits SERCA function) and increased SERCA levels. The lower relative ratio of PLB to SERCA leads to less inhibition of SERCA and increased Ca2+-uptake which enhances relaxation and contraction in human atrium.
Neuronal Nitric Oxide Reduces Sympathetic Excitability by Modulation of Central Glutamate Effects in Pigs
Authors: Johannes Zanzinger, Jürgen Czachurski, Horst Seller
Journal: Circulation Research (1997)

Mechanisms of the modulation of sympathetic activity by neuronal NO were studied in vagotomized anesthetized pigs. Inhibition of neuronal NO synthase (nNOS) within the brain stem by intracerebroventricular (ICV) administration of 7-nitroindazole (7-NI, 1 mmol/L) or S-methyl-L-thiocitrulline (MeTC, 0.1 mmol/L) caused slight increases in renal sympathetic nerve activity (RSNA) but did not affect arterial blood pressure (BP) or cardiac output (CO). However, the sympathoexcitatory effects of glutamate (0.5 mL, 0.1 mol/L ICV) that were associated with marked increases in BP, CO, and heart rate were potentiated by both nNOS inhibitors. Furthermore, 7-NI and MeTC significantly enhanced the responses of RSNA, BP, and CO to activation of somatosympathetic reflexes via stimulation of the left greater sciatic nerve (nervus ischiadicus, 10 to 20 V, 30 Hz, 1-millisecond pulses). Subsequent systemic inhibition of either the neuronal (by 7-NI) or all isoforms of NOS by NG-nitro-L-arginine-methyl ester (20 mg/kg) had no significant additional effects on these responses. The effects of NOS inhibition were effectively counteracted by the endogenous NOS substrate L-arginine and by S-nitroso-N-acetyl-penicillamine (SNAP), a stable analogue of endogenous S-nitroso factors. Disruption of sympathoinhibitory baroreflex mechanisms by bilateral cutting of the carotid sinus nerves caused increases in RSNA and slightly increased responses to all excitatory stimuli but had no effects on the actions of the NOS inhibitors or SNAP. These results suggest that modulation of glutamate effects by nNOS-derived NO may be an important mechanism by which NO affects sympathetic activity in pigs.
A Novel Mechanism for the Immunomodulatory Functions of Class II MHC–Derived Peptides
Authors: Barbara Murphy, Joyce Yu, Qingsheng Jiao, Marvin Lin, Tanuja Chitnis, Mohamed H. Sayegh
Journal: Journal of the American Society of Nephrology (2003)

ABSTRACT. There is now extensive evidence that synthetic peptides corresponding to linear sequences of MHC molecules are effective immunoregulators, targeting the immune response at many different sites. It has been previously shown that peptides derived from a highly conserved region of MHC class II inhibit proliferation to autoantigen and to both the direct and indirect pathways of allorecognition. This study demonstrates that inhibition of lymphocyte proliferation by nonpolymorphic MHC class II peptides, specifically HLA-DQA1, is sequence-specific and that the inhibitory effect is mediated through the induction of apoptosis in antigen-presenting cells via a caspase-independent mechanism. In addition, T lymphocytes stimulated in the presence of HLA-DQA1 are rendered hyporesponsive to subsequent stimuli. Immunomodulation by HLA-DQA1 is effective in vivo because it prevents both the priming and the effector function of primed allogeneic T cells in a murine DTH model. These observations have important implications for the development of a novel therapy for immune-mediated diseases. E-mail: [email protected]
Interferon-alpha (IFN-alpha) production by human intestinal mononuclear cells. Response to virus in control subjects and in Crohn's disease.
Authors: M R Capobianchi, S Fais, F Mercuri, M Boirivant, F Dianzani, F Pallone
Journal: Gut (1992)

The virus induced production of interferon alpha by human intestinal lamina propria mononuclear cells was investigated. Intestinal and autologous peripheral cells from control subjects and patients with Crohn9s disease were cultured in vitro with and without stimulation with the Newcastle disease virus. Interferon alpha was measured and characterised in the culture supernatants after 12 hours and the kinetics of production was evaluated over the following four days of culture. No detectable interferon alpha was found in cultures of unstimulated intestinal and autologous peripheral mononuclear cells from controls and Crohn9s disease whereas interferon alpha was released in all cultures stimulated with the virus. In all 12 hours experiments in both groups, virus stimulated intestinal mononuclear cells yielded significantly less interferon alpha than the autologous peripheral cells. The kinetics experiments showed that control intestinal mononuclear cells appeared to be poorly responsive to virus stimulation showing a release of interferon alpha significantly lower than that of the autologous peripheral cells. The interferon alpha release at day 4 by control cells (either intestinal or peripheral) did not differ from that measured after the first 12 hours. In contrast, the interferon alpha produced by Crohn9s disease cells progressively increased during the culture period and the amount of interferon alpha measured at day 4 was significantly higher than that released at 12 hours. These data suggest that normal human intestinal mononuclear cells are down regulated in their capability of producing interferon alpha and that in Crohn9s disease their activation for this function is enhanced. These data also suggest that in Crohn9s disease intestinal mononuclear cells exhibit a transient hyporesponsiveness to in vitro stimulation possibly related to massive in vivo exposure to interferon alpha inducers.
High rates of over-treatment of COPD in primary care: What risks to patients and costs to health services?
Authors: Helen Booth, Sofia Georgopoulou, Hilary Pinnock, Hannah Thornton, Patrick White
Journal: European Respiratory Journal (2011)

Introduction:  GOLD guidelines recommend inhaled medications for COPD based on disease severity. Undertreatment denies patients the benefits of effective therapy. Overtreatment with inhaled corticosteroids (ICS) risks side-effects including both local and increased risk of pneumonia; in combination with long-acting beta-agonists they also incur considerable financial waste. This study assessed adherence to GOLD guidelines in primary care prescribing of inhaled COPD medication in South-East London.   Methods:  Data on management of COPD patients were extracted in 65 general practices in Lambeth and Southwark including spirometry, inhaled medications and recent COPD exacerbations. Patient severity was classed by GOLD stage and appropriateness of prescribing was assessed.   Results:  4804 COPD patients were identified. Spirometry was recorded for 2941 (61%), of whom 778 did not meet GOLD diagnostic criteria. 2163 (45%) were included in the analysis. 62% were inappropriately treated according to GOLD. The most common deviation was over-prescription of ICS in GOLD I/II (55%), or III/IV with no history of severe exacerbations (56%). 793 (64%) cases of over-treatment involved LABA+ICS with a mean cost of €46.52/item.   Conclusion:  Diagnosis of COPD was made without spirometry in the majority of COPD patients in primary care. Deviation from GOLD in prescribing was substantial. The potential for harm due to ICS over-prescription in over half of patients with a confirmed diagnosis of COPD must give considerable cause for concern, besides the unjustified costs.
Long-Term Radioiodine Retention and Regression of Liver Cancer after Sodium Iodide Symporter Gene Transfer in Wistar Rats
Authors: Jamila Faivre, Jérôme Clerc, René Gérolami, Julie Hervé, Michèle Longuet, Bingkai Liu, Jérôme Roux, Frédéric Moal, Michel Perricaudet, Christian Bréchot
Journal: Cancer Research (2004)

Abstract Radioiodine therapy of nonthyroid cancers after sodium iodide symporter (NIS) gene delivery has been proposed as a potential application of gene therapy. However, it seems to be precluded by the rapid efflux of taken up iodine from most transduced xenografted tumors. We present an in vivo kinetic study of NIS-related hepatic iodine uptake in an aggressive model of hepatocarcinoma induced by diethylnitrosamine in immunocompetent Wistar rats. We followed the whole-body iodine distribution by repeated imaging of live animals. We constructed a rat NIS (rNIS) adenoviral vector, Ad-CMV-rNIS, using the cytomegalovirus (CMV) as a promoter. Injected in the portal vein in 5 healthy and 25 hepatocarcinoma-bearing rats and liver tumors in 9 hepatocarcinoma-bearing rats, Ad-CMV-rNIS drove expression of a functional NIS protein by hepatocytes and allowed marked (from 20 to 30% of the injected dose) and sustained (&amp;gt;11 days) iodine uptake. This contrasts with the massive iodine efflux found in vitro in human hepatic tumor cell lines. In vivo specific inhibition of NIS by sodium perchlorate led to a rapid iodine efflux from the liver, indicating that the sustained uptake was not attributable to an active retention mechanism but to permanent recycling of the effluent radioiodine via the high hepatic blood flow. Radioiodine therapy after Ad-CMV-rNIS administration achieved a strong inhibition of tumor growth, the complete regression of small nodules, and prolonged survival of hepatocarcinoma-bearing rats. This demonstrates for the first time the efficacy of NIS-based radiotherapy in a relevant preclinical model of nonthyroid human carcinogenesis.
Role of intracellular pH during cytoprotection of proximal tubule cells by glycine or acidosis.
Authors: J M Weinberg, J A Davis, N F Roeser, M A Venkatachalam
Journal: Journal of the American Society of Nephrology (1994)

Lowering extracellular pH to less than 7.0 strongly protects isolated proximal tubules against ATP depletion and Ca(2+)-induced injury, but there is little information about alterations of intracellular pH (pHi) in renal tubules during either injury or its modification by decreasing medium pHi or other potent protective factors such as glycine. pHi was assessed with 2',7'-bis-(2-carboxyethyl)-5-carboxyfluorescein during proximal tubule injury produced by simple ATP depletion with the electron transport inhibitor antimycin or by large increases of cytosolic free Ca2+ induced by treatment with the calcium ionophore ionomycin, alone and in combination with antimycin. Freshly isolated rabbit proximal tubules studied under superfusion conditions in the presence of probenecid were suitable for monitoring pHi during relatively prolonged and severe injury states. Probenecid, used to promote the retention of intracellular fluorophores, only minimally modified the injury response by transiently delaying lactate dehydrogenase release during antimycin treatment. The tubules did not exhibit spontaneous decreases of pHi during simple ATP depletion, but pHi fully equilibrated with cytoprotective decreases of medium pH. Irrespective of the presence of antimycin, ionomycin induced intracellular alkalinization in Ca(2+)-replete medium, which may have further enhanced the severity of injury. When medium Ca2+ was buffered to 100 nM, ionomycin induced intracellular acidification, which likely resulted from a combination of Ca2+/H+ exchange activity of the ionophore and H+ uptake during Ca(2+)-ATPase-mediated extrusion of Ca2+ released by ionomycin from intracellular pools. Alterations of pHi did not contribute to glycine cytoprotection because glycine did not affect the behavior of pHi during treatment with antimycin, ionomycin, or both agents in combination.(ABSTRACT TRUNCATED AT 250 WORDS)
Commentary on “Effects of ischaemia and reperfusion on calcium exchange and mechanical function in isolated rabbit myocardium”
Authors: P Bourdillon
Journal: Cardiovascular Research (2000)

Rereading and commenting upon an article written 18 years ago is almost to intrude on the prerogatives of history. Wallowing in nostalgia may be a satisfying activity but is not a plausible method for identifying, posing or answering scientific questions. I reread this paper with trepidation but was relieved, perhaps the correct sentiment, to find that it still addressed an important issue. More surprising was the realisation of how limited has been the progress made over the last two decades.

In 1974, as a young research worker, I was fortunate to work in the laboratories of Glen Langer in Los Angeles, supported by the British Heart Foundation. Previously in London I had been investigating the net change in potassium homeostasis in cardiac and skeletal muscle, in vivo, in response to alterations of acid–base balance. Glen Langer had developed a technique which allowed the measurement not just of tissue content of an ion but of ion fluxes. The technique allowed examination of the effect of acid–base changes on potassium fluxes so as to explain the previously observed net changes [1]. Later this same technique was adapted to measure the flux of calcium isotopes (45Ca2+ and 47Ca2+) into and out of the myocardium [2]. Bourdillon developed the system further so that measurements could be made during and after a period of ischaemia. That formed the basis of the paper published in Cardiovascular Research [3].

The technique used was the arterially perfused intraventricular septum of the rabbit heart. A small cannula is inserted into the first septal artery which in the rabbit comes off shortly after the origin of the left anterior descending coronary artery. Non perfused tissue is cut away so that a small triangular of piece of myocardium …
Determinants of prescription and choice of empirical therapy for hospital-acquired and ventilator-associated pneumonia
Authors: J. Rello, M. Ulldemolins, T. Lisboa, D. Koulenti, R. Mañez, I. Martin-Loeches, J.J. De Waele, C. Putensen, M. Guven, M. Deja, E. Diaz
Journal: European Respiratory Journal (2010)

The objectives of this study were to assess the determinants of empirical antibiotic choice, prescription patterns and outcomes in patients with hospital-acquired pneumonia (HAP)/ventilator-associated pneumonia (VAP) in Europe. We performed a prospective, observational cohort study in 27 intensive care units (ICUs) from nine European countries. 100 consecutive patients on mechanical ventilation for HAP, on mechanical ventilation &gt;48 h or with VAP were enrolled per ICU. Admission category, sickness severity and Acinetobacter spp. prevalence &gt;10% in pneumonia episodes determined antibiotic empirical choice. Trauma patients were more often prescribed non-anti- Pseudomonas cephalosporins (OR 2.68, 95% CI 1.50–4.78). Surgical patients received less aminoglycosides (OR 0.26, 95% CI 0.14–0.49). A significant correlation (p&lt;0.01) was found between Simplified Acute Physiology Score II score and carbapenem prescription. Basal Acinetobacter spp. prevalence &gt;10% dramatically increased the prescription of carbapenems (OR 3.5, 95% CI 2.0–6.1) and colistin (OR 115.7, 95% CI 6.9–1,930.9). Appropriate empirical antibiotics decreased ICU length of stay by 6 days (26.3±19.8 days versus 32.8±29.4 days; p = 0.04). The antibiotics that were prescribed most were carbapenems, piperacillin/tazobactam and quinolones. Median (interquartile range) duration of antibiotic therapy was 9 (6–12) days. Anti-methicillin-resistant Staphylococcus aureus agents were prescribed in 38.4% of VAP episodes. Admission category, sickness severity and basal Acinetobacter prevalence &gt;10% in pneumonia episodes were the major determinants of antibiotic choice at the bedside. Across Europe, carbapenems were the antibiotic most prescribed for HAP/VAP.