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1.
medRxiv ; 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38562733

ABSTRACT

Hyperpolarization activated Cyclic Nucleotide (HCN) gated channels are crucial for various neurophysiological functions, including learning and sensory functions, and their dysfunction are responsible for brain disorders, such as epilepsy. To date, HCN2 variants have only been associated with mild epilepsy and recently, one monoallelic missense variant has been linked to developmental and epileptic encephalopathy. Here, we expand the phenotypic spectrum of HCN2- related disorders by describing twenty-one additional individuals from fifteen unrelated families carrying HCN2 variants. Seventeen individuals had developmental delay/intellectual disability (DD/ID), two had borderline DD/ID, and one had borderline DD. Ten individuals had epilepsy with DD/ID, with median age of onset of 10 months, and one had epilepsy with normal development. Molecular diagnosis identified thirteen different pathogenic HCN2 variants, including eleven missense variants affecting highly conserved amino acids, one frameshift variant, and one in-frame deletion. Seven variants were monoallelic of which five occurred de novo, one was not maternally inherited, one was inherited from a father with mild learning disabilities, and one was of unknown inheritance. The remaining six variants were biallelic, with four homozygous and two compound heterozygous variants. Functional studies using two-electrode voltage-clamp recordings in Xenopus laevis oocytes were performed on three monoallelic variants, p.(Arg324His), p.(Ala363Val), and p.(Met374Leu), and three biallelic variants, p.(Leu377His), p.(Pro493Leu) and p.(Gly587Asp). The p.(Arg324His) variant induced a strong increase of HCN2 conductance, while p.(Ala363Val) and p.(Met374Leu) displayed dominant negative effects, leading to a partial loss of HCN2 channel function. By confocal imaging, we found that the p.(Leu377His), p.(Pro493Leu) and p.(Gly587Asp) pathogenic variants impaired membrane trafficking, resulting in a complete loss of HCN2 elicited currents in Xenopus oocytes. Structural 3D-analysis in depolarized and hyperpolarized states of HCN2 channels, revealed that the pathogenic variants p.(His205Gln), p.(Ser409Leu), p.(Arg324Cys), p.(Asn369Ser) and p.(Gly460Asp) modify molecular interactions altering HCN2 function. Taken together, our data broadens the clinical spectrum associated with HCN2 variants, and disclose that HCN2 is involved in developmental encephalopathy with or without epilepsy.

2.
Mar Drugs ; 21(3)2023 Mar 22.
Article in English | MEDLINE | ID: mdl-36976245

ABSTRACT

Tetrodotoxin (TTX) poisoning through the consumption of contaminated fish leads to lethal symptoms, including severe hypotension. This TTX-induced hypotension is likely due to the downfall of peripheral arterial resistance through direct or indirect effects on adrenergic signaling. TTX is a high-affinity blocker of voltage-gated Na+ (NaV) channels. In arteries, NaV channels are expressed in sympathetic nerve endings, both in the intima and media. In this present work, we aimed to decipher the role of NaV channels in vascular tone using TTX. We first characterized the expression of NaV channels in the aorta, a model of conduction arteries, and in mesenteric arteries (MA), a model of resistance arteries, in C57Bl/6J mice, by Western blot, immunochemistry, and absolute RT-qPCR. Our data showed that these channels are expressed in both endothelium and media of aorta and MA, in which scn2a and scn1b were the most abundant transcripts, suggesting that murine vascular NaV channels consist of NaV1.2 channel subtype with NaVß1 auxiliary subunit. Using myography, we showed that TTX (1 µM) induced complete vasorelaxation in MA in the presence of veratridine and cocktails of antagonists (prazosin and atropine with or without suramin) that suppressed the effects of neurotransmitter release. In addition, TTX (1 µM) strongly potentiated the flow-mediated dilation response of isolated MA. Altogether, our data showed that TTX blocks NaV channels in resistance arteries and consecutively decreases vascular tone. This could explain the drop in total peripheral resistance observed during mammal tetrodotoxications.


Subject(s)
Aorta , Mesenteric Arteries , Mice , Animals , Tetrodotoxin/pharmacology , Mammals , Voltage-Gated Sodium Channel beta-1 Subunit
3.
BMC Cancer ; 22(1): 843, 2022 Aug 02.
Article in English | MEDLINE | ID: mdl-35918659

ABSTRACT

BACKGROUND: Glioblastoma (GB) is the most common and most aggressive malignant brain tumor. In understanding its resistance to conventional treatments, iron metabolism and related pathways may represent a novel avenue. As for many cancer cells, GB cell growth is dependent on iron, which is tightly involved in red-ox reactions related to radiotherapy effectiveness. From new observations indicating an impact of RX radiations on the expression of ceruloplasmin (CP), an important regulator of iron metabolism, the aim of the present work was to study the functional effects of constitutive expression of CP within GB lines in response to beam radiation depending on the oxygen status (21% O2 versus 3% O2). METHODS AND RESULTS: After analysis of radiation responses (Hoechst staining, LDH release, Caspase 3 activation) in U251-MG and U87-MG human GB cell lines, described as radiosensitive and radioresistant respectively, the expression of 9 iron partners (TFR1, DMT1, FTH1, FTL, MFRN1, MFRN2, FXN, FPN1, CP) were tested by RTqPCR and western blots at 3 and 8 days following 4 Gy irradiation. Among those, only CP was significantly downregulated, both at transcript and protein levels in the two lines, with however, a weaker effect in the U87-MG, observable at 3% O2. To investigate specific role of CP in GB radioresistance, U251-MG and U87-MG cells were modified genetically to obtain CP depleted and overexpressing cells, respectively. Manipulation of CP expression in GB lines demonstrated impact both on cell survival and on activation of DNA repair/damage machinery (γH2AX); specifically high levels of CP led to increased production of reactive oxygen species, as shown by elevated levels of superoxide anion, SOD1 synthesis and cellular Fe2 + . CONCLUSIONS: Taken together, these in vitro results indicate for the first time that CP plays a positive role in the efficiency of radiotherapy on GB cells.


Subject(s)
Brain Neoplasms , Glioblastoma , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Brain Neoplasms/radiotherapy , Cell Line, Tumor , Ceruloplasmin/genetics , Ceruloplasmin/metabolism , Ceruloplasmin/pharmacology , Glioblastoma/genetics , Glioblastoma/metabolism , Glioblastoma/radiotherapy , Humans , Iron/pharmacology , Oxygen/metabolism , Radiation Tolerance/genetics
4.
Molecules ; 27(13)2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35807390

ABSTRACT

Voltage-gated Na+ (NaV) channels are significant therapeutic targets for the treatment of cardiac and neurological disorders, thus promoting the search for novel NaV channel ligands. With the objective of discovering new blockers of NaV channel ligands, we screened an In-House vegetal alkaloid library using fluorescence cell-based assays. We screened 62 isoquinoline alkaloids (IA) for their ability to decrease the FRET signal of voltage sensor probes (VSP), which were induced by the activation of NaV channels with batrachotoxin (BTX) in GH3b6 cells. This led to the selection of five IA: liriodenine, oxostephanine, thalmiculine, protopine, and bebeerine, inhibiting the BTX-induced VSP signal with micromolar IC50. These five alkaloids were then assayed using the Na+ fluorescent probe ANG-2 and the patch-clamp technique. Only oxostephanine and liriodenine were able to inhibit the BTX-induced ANG-2 signal in HEK293-hNaV1.3 cells. Indeed, liriodenine and oxostephanine decreased the effects of BTX on Na+ currents elicited by the hNaV1.3 channel, suggesting that conformation change induced by BTX binding could induce a bias in fluorescent assays. However, among the five IA selected in the VSP assay, only bebeerine exhibited strong inhibitory effects against Na+ currents elicited by the hNav1.2 and hNav1.6 channels, with IC50 values below 10 µM. So far, bebeerine is the first BBIQ to have been reported to block NaV channels, with promising therapeutical applications.


Subject(s)
Alkaloids , Fluorescent Dyes , Alkaloids/pharmacology , Batrachotoxins/metabolism , Batrachotoxins/pharmacology , Bias , HEK293 Cells , Humans , Isoquinolines/pharmacology , Ligands , Sodium/metabolism
5.
Int J Mol Sci ; 23(2)2022 Jan 13.
Article in English | MEDLINE | ID: mdl-35055012

ABSTRACT

Thanks to the crosstalk between Na+ and Ca2+ channels, Na+ and Ca2+ homeostasis interplay in so-called excitable cells enables the generation of action potential in response to electrical stimulation. Here, we investigated the impact of persistent activation of voltage-gated Na+ (NaV) channels by neurotoxins, such as veratridine (VTD), on intracellular Ca2+ concentration ([Ca2+]i) in a model of excitable cells, the rat pituitary GH3b6 cells, in order to identify the molecular actors involved in Na+-Ca2+ homeostasis crosstalk. By combining RT-qPCR, immunoblotting, immunocytochemistry, and patch-clamp techniques, we showed that GH3b6 cells predominantly express the NaV1.3 channel subtype, which likely endorses their voltage-activated Na+ currents. Notably, these Na+ currents were blocked by ICA-121431 and activated by the ß-scorpion toxin Tf2, two selective NaV1.3 channel ligands. Using Fura-2, we showed that VTD induced a [Ca2+]i increase. This effect was suppressed by the selective NaV channel blocker tetrodotoxin, as well by the selective L-type CaV channel (LTCC) blocker nifedipine. We also evidenced that crobenetine, a NaV channel blocker, abolished VTD-induced [Ca2+]i elevation, while it had no effects on LTCC. Altogether, our findings highlight a crosstalk between NaV and LTCC in GH3b6 cells, providing a new insight into the mode of action of neurotoxins.


Subject(s)
Large-Conductance Calcium-Activated Potassium Channels/metabolism , Signal Transduction/drug effects , Voltage-Gated Sodium Channels/metabolism , Animals , Calcium/metabolism , Cell Line , Electrophysiological Phenomena , Fluorescent Antibody Technique , Gene Expression , High-Throughput Screening Assays , Ion Channel Gating/drug effects , Large-Conductance Calcium-Activated Potassium Channels/genetics , Neurotoxins/pharmacology , Patch-Clamp Techniques , Protein Binding , Protein Isoforms , Rats , Voltage-Gated Sodium Channels/genetics
6.
Front Neurosci ; 15: 768466, 2021.
Article in English | MEDLINE | ID: mdl-34912189

ABSTRACT

Fipronil (FPN) is a worldwide-used neurotoxic insecticide, targeting, and blocking GABAA receptors (GABAARs). Beyond its efficiency on insect GABAARs, FPN causes neurotoxic effects in humans and mammals. Here, we investigated the mode of action of FPN on mammalian α6-containing GABAARs to understand its inhibitory effects on GABA-induced currents, as a function of the synaptic or extrasynaptic localization of GABAARs. We characterized the effects of FPN by electrophysiology using Xenopus oocytes which were microtransplanted with cerebellum membranes or injected with α6ß3, α6ß3γ2S (synaptic), and α6ß3δ (extrasynaptic) cDNAs. At micromolar concentrations, FPN dose-dependently inhibited cerebellar GABA currents. FPN acts as a non-competitive antagonist on ternary receptors. Surprisingly, the inhibition of GABA-induced currents was partial for extra-synaptic (α6ß3δ) and binary (α6ß3) receptors, while synaptic α6ß3γ2S receptors were fully blocked, indicating that the complementary γ or δ subunit participates in FPN-GABAAR interaction. FPN unexpectedly behaved as a positive modulator on ß3 homopentamers. These data show that FPN action is driven by the subunit composition of GABAARs-highlighting the role of the complementary subunit-and thus their localization within a physiological synapse. We built a docking model of FPN on GABAARs, which reveals two putative binding sites. This is consistent with a double binding mode of FPN on GABAARs, possibly one being of high affinity and the other of low affinity. Physiologically, the γ/δ subunit incorporation drives its inhibitory level and has important significance for its toxicity on the mammalian nervous system, especially in acute exposure.

7.
Int J Mol Sci ; 22(10)2021 May 12.
Article in English | MEDLINE | ID: mdl-34065933

ABSTRACT

Neonicotinoid insecticides are nicotine-derived molecules which exert acute neurotoxic effects over the insect central nervous system by activating nicotinic acetylcholine receptors (nAChRs). However, these receptors are also present in the mammalian central and peripheral nervous system, where the effects of neonicotinoids are faintly known. In mammals, cholinergic synapses are crucial for the control of vascular tone, blood pressure and skeletal muscle contraction. We therefore hypothesized that neonicotinoids could affect cholinergic networks in mammals and sought to highlight functional consequences of acute intoxication in rats with sub-lethal concentrations of the highly used acetamiprid (ACE) and clothianidin (CLO). In this view, we characterized their electrophysiological effects on rat α3ß4 nAChRs, knowing that it is predominantly expressed in ganglia of the vegetative nervous system and the adrenal medulla, which initiates catecholamine secretion. Both molecules exhibited a weak agonist effect on α3ß4 receptors. Accordingly, their influence on epinephrine secretion from rat adrenal glands was also weak at 100 µM, but it was stronger at 500 µM. Challenging ACE or CLO together with nicotine (NIC) ended up with paradoxical effects on secretion. In addition, we measured the rat arterial blood pressure (ABP) in vivo by arterial catheterization. As expected, NIC induced a significant increase in ABP. ACE and CLO did not affect the ABP in the same conditions. However, simultaneous exposure of rats to both NIC and ACE/CLO promoted an increase of ABP and induced a biphasic response. Modeling the interaction of ACE or CLO on α3ß4 nAChR is consistent with a binding site located in the agonist pocket of the receptor. We present a transversal experimental approach of mammal intoxication with neonicotinoids at different scales, including in vitro, ex vivo, in vivo and in silico. It paves the way of the acute and chronic toxicity for this class of insecticides on mammalian organisms.


Subject(s)
Epinephrine/metabolism , Insecticides/toxicity , Neonicotinoids/toxicity , Nicotine/toxicity , Receptors, Nicotinic/metabolism , Adrenal Medulla/drug effects , Adrenal Medulla/metabolism , Animals , Arterial Pressure/drug effects , Disease Models, Animal , Drug Partial Agonism , Ganglia/drug effects , Ganglia/metabolism , Gene Expression Regulation/drug effects , Guanidines/toxicity , Male , Rats , Thiazoles/toxicity , Toxicity Tests, Subacute
8.
Theranostics ; 7(18): 4517-4536, 2017.
Article in English | MEDLINE | ID: mdl-29158842

ABSTRACT

PURPOSE: Gold standard beam radiation for glioblastoma (GBM) treatment is challenged by resistance phenomena occurring in cellular populations well prepared to survive or to repair damage caused by radiation. Among signals that have been linked with radio-resistance, the SDF1/CXCR4 axis, associated with cancer stem-like cell, may be an opportune target. To avoid the problem of systemic toxicity and blood-brain barrier crossing, the relevance and efficacy of an original system of local brain internal radiation therapy combining a radiopharmaceutical with an immuno-nanoparticle was investigated. EXPERIMENT DESIGN: The nanocarrier combined lipophilic thiobenzoate complexes of rhenium-188 loaded in the core of a lipid nanocapsule (LNC188Re) with a function-blocking antibody, 12G5 directed at the CXCR4, on its surface. The efficiency of 12G5-LNC188Re was investigated in an orthotopic and xenogenic GBM model of CXCR4-positive U87MG cells implanted in the striatum of Scid mice. RESULTS: We demonstrated that 12G5-LNC188Re single infusion treatment by convection-enhanced delivery resulted in a major clinical improvement in median survival that was accompanied by locoregional effects on tumor development including hypovascularization and stimulation of the recruitment of bone marrow derived CD11b- or CD68-positive cells as confirmed by immunohistochemistry analysis. Interestingly, thorough analysis by spectral imaging in a chimeric U87MG GBM model containing CXCR4-positive/red fluorescent protein (RFP)-positive- and CXCR4-negative/RFP-negative-GBM cells revealed greater confinement of DiD-labeled 12G5-LNCs than control IgG2a-LNCs in RFP compartments. Main conclusion: These findings on locoregional impact and targeting of disseminated cancer cells in tumor margins suggest that intracerebral active targeting of nanocarriers loaded with radiopharmaceuticals may have considerable benefits in clinical applications.


Subject(s)
Brain Neoplasms/radiotherapy , Glioblastoma/radiotherapy , Nanoparticles/administration & dosage , Radioisotopes/administration & dosage , Radiopharmaceuticals/administration & dosage , Receptors, CXCR4/administration & dosage , Rhenium/administration & dosage , Animals , Blood-Brain Barrier/metabolism , Brain/radiation effects , Cell Line, Tumor , Disease Models, Animal , Female , Humans , Lipids/administration & dosage , Mice , Nanocapsules/administration & dosage , Neoplastic Stem Cells/radiation effects , Xenograft Model Antitumor Assays/methods
9.
BMC Cancer ; 16: 51, 2016 Feb 01.
Article in English | MEDLINE | ID: mdl-26832741

ABSTRACT

BACKGROUND: Overcoming resistance to treatment is an essential issue in many cancers including glioblastoma (GBM), the deadliest primary tumor of the central nervous system. As dependence on iron is a key feature of tumor cells, using chelators to reduce iron represents an opportunity to improve conventional GBM therapies. The aim of the present study was, therefore, to investigate the cytostatic and cytotoxic impact of the new iron chelator deferasirox (DFX) on human GBM cells in well-defined clinical situations represented by radiation therapy and mild-hypoxia. RESULTS: Under experimental normoxic condition (21% O2), deferasirox (DFX) used at 10 µM for 3 days reduced proliferation, led cell cycle arrest in S and G2-M phases and induced cytotoxicity and apoptosis in U251 and U87 GBM cells. The abolition of the antineoplastic DFX effects when cells were co-treated with ferric ammonium sulfate supports the hypothesis that its effects result from its ability to chelate iron. As radiotherapy is the main treatment for GBM, the combination of DFX and X-ray beam irradiation was also investigated. Irradiation at a dose of 16 Gy repressed proliferation, cytotoxicity and apoptosis, but only in U251 cells, while no synergy with DFX was observed in either cell line. Importantly, when the same experiment was conducted in mild-hypoxic conditions (3% O2), the antiproliferative and cytotoxic effects of DFX were abolished, and its ability to deplete iron was also impaired. CONCLUSIONS: Taken together, these in vitro results could raise the question of the benefit of using iron chelators in their native forms under the hypoxic conditions often encountered in solid tumors such as GBM. Developing new chemistry or a new drug delivery system that would keep DFX active in hypoxic cells may be the next step toward their application.


Subject(s)
Benzoates/administration & dosage , Cell Hypoxia , Glioblastoma/metabolism , Iron Chelating Agents/administration & dosage , Triazoles/administration & dosage , Cell Line, Tumor , Combined Modality Therapy , Deferasirox , Drug Resistance, Neoplasm/genetics , Glioblastoma/drug therapy , Glioblastoma/pathology , Glioblastoma/radiotherapy , Humans , Oxygen/metabolism
10.
Trends Endocrinol Metab ; 26(6): 322-31, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25936466

ABSTRACT

Glioblastoma (GBM), the deadliest primary tumor of the central nervous system (CNS), is a clear illustration of the resistance of cancer cells to conventional therapies. Application of combinatorial strategies able to overcome pivotal factors of GBM resistance, particularly within the resection margins, represents an essential issue. This review focuses on the role of iron metabolism in GBM progression and resistance to therapy, and the impact of its pharmaceutical modulation on the disease. Iron, through its involvement in many biological processes, is a key factor in the control of cell behavior and cancer biology. Therefore, targeting cellular iron signaling or taking advantage of its dysregulation in cancer cells may lead to new opportunities for improving treatments and drug delivery in GBM.


Subject(s)
Glioblastoma/metabolism , Iron/metabolism , Antineoplastic Agents/therapeutic use , Drug Resistance, Neoplasm , Glioblastoma/drug therapy , Humans , Signal Transduction/drug effects
11.
PLoS One ; 9(7): e102200, 2014.
Article in English | MEDLINE | ID: mdl-25010049

ABSTRACT

The statin family of cholesterol-lowering drugs is known to have pleiotropic properties which include anti-inflammatory and immunomodulatory effects. Statins exert their pleiotropic effects by altering expression of human immune regulators including pro-inflammatory cytokines. Previously we found that statins modulate virulence phenotypes of the human pathogen Pseudomonas aeruginosa, and sought to investigate if simvastatin could alter the host response to this organism in lung epithelial cells. Simvastatin increased the expression of the P. aeruginosa target genes KLF2, KLF6, IL-8 and CCL20. Furthermore, both simvastatin and P. aeruginosa induced alternative splicing of KLF6. The novel effect of simvastatin on wtKLF6 expression was found to be responsible for induction of the KLF6 regulated genes CCL20 and iNOS. Simvastatin also increased the adhesion of P. aeruginosa to host cells, without altering invasion or cytotoxicity. This study demonstrated that simvastatin had several novel effects on the pulmonary cellular immune response.


Subject(s)
Gene Expression Regulation/drug effects , Pseudomonas Infections/drug therapy , Pseudomonas aeruginosa/drug effects , Simvastatin/administration & dosage , Alternative Splicing/drug effects , Cell Line , Chemokine CCL20/biosynthesis , Humans , Immunity, Cellular/drug effects , Interleukin-8/biosynthesis , Kruppel-Like Factor 6 , Kruppel-Like Transcription Factors/biosynthesis , Lung/drug effects , Lung/immunology , Lung/pathology , Proto-Oncogene Proteins/biosynthesis , Pseudomonas Infections/genetics , Pseudomonas Infections/pathology , Pseudomonas aeruginosa/pathogenicity
12.
Infect Immun ; 82(9): 3531-41, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24914220

ABSTRACT

Gastroesophageal reflux (GER) frequently occurs in patients with respiratory disease and is particularly prevalent in patients with cystic fibrosis. GER is a condition in which the duodenogastric contents of the stomach leak into the esophagus, in many cases resulting in aspiration into the respiratory tract. As such, the presence of GER-derived bile acids (BAs) has been confirmed in the bronchoalveolar lavage fluid and sputum of affected patients. We have recently shown that bile causes cystic fibrosis-associated bacterial pathogens to adopt a chronic lifestyle and may constitute a major host trigger underlying respiratory infection. The current study shows that BAs elicit a specific response in humans in which they repress hypoxia-inducible factor 1α (HIF-1α) protein, an emerging master regulator in response to infection and inflammation. HIF-1α repression was shown to occur through the 26S proteasome machinery via the prolyl hydroxylase domain (PHD) pathway. Further analysis of the downstream inflammatory response showed that HIF-1α repression by BAs can significantly modulate the immune response of airway epithelial cells, correlating with a decrease in interleukin-8 (IL-8) production, while IL-6 production was strongly increased. Importantly, the effects of BAs on cytokine production can also be more dominant than the bacterium-mediated effects. However, the effect of BAs on cytokine levels cannot be fully explained by their ability to repress HIF-1α, which is not surprising, given the complexity of the immune regulatory network. The suppression of HIF-1 signaling by bile acids may have a significant influence on the progression and outcome of respiratory disease, and the molecular mechanism underpinning this response warrants further investigation.


Subject(s)
Bile Acids and Salts/immunology , Bile Acids and Salts/pharmacology , Epithelial Cells/immunology , Hypoxia-Inducible Factor 1, alpha Subunit/antagonists & inhibitors , Respiratory System/drug effects , Respiratory System/immunology , Signal Transduction/drug effects , Cell Line , Cell Line, Tumor , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Inflammation/immunology , Inflammation/metabolism , Interleukin-6/immunology , Interleukin-6/metabolism , Interleukin-8/immunology , Interleukin-8/metabolism , Prolyl Hydroxylases/immunology , Prolyl Hydroxylases/metabolism , Proteasome Endopeptidase Complex/immunology , Proteasome Endopeptidase Complex/metabolism , Respiratory System/metabolism , Signal Transduction/immunology
13.
Reprod Biomed Online ; 26(6): 542-54, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23518032

ABSTRACT

Although selective termination of pregnancy and fetal reduction in multiple pregnancy both involve the termination in utero of the development of live fetuses, these two procedures are different in several aspects. Nevertheless, several authors tend to amalgamate and confuse their psychosocial consequences and the ethical issues they raise. Therefore, this narrative review, derived from a comparative analysis of 91 articles, shines a light on these amalgamations and confusions, as well as on the medical, contextual, experiential and ethical differences specific to selective termination and fetal reduction.


Subject(s)
Abortion, Induced , Pregnancy Reduction, Multifetal , Pregnancy, Multiple , Ethics , Female , Humans , Pregnancy
15.
Org Biomol Chem ; 10(44): 8903-10, 2012 Nov 28.
Article in English | MEDLINE | ID: mdl-23051988

ABSTRACT

2-Heptyl-3-hydroxy-4-quinolone (PQS) and its precursor 2-heptyl-4-quinolone (HHQ) are key signalling molecules of the important nosocomial pathogen Pseudomonas aeruginosa. We have recently reported an interkingdom dimension to these molecules, influencing key virulence traits in a broad spectrum of microbial species and in the human pathogenic yeast Candida albicans. For the first time, targeted chemical derivatisation of the C-3 position was undertaken to investigate the structural and molecular properties underpinning the biological activity of these compounds in P. aeruginosa, and using Bacillus subtilis as a suitable model system for investigating modulation of interspecies behaviour.


Subject(s)
4-Quinolones/chemistry , 4-Quinolones/metabolism , Bacillus subtilis/physiology , Pseudomonas aeruginosa/physiology , Quinolones/chemistry , Quinolones/metabolism , 4-Quinolones/chemical synthesis , Biofilms , Cell Line , Humans , Models, Molecular , Quinolones/chemical synthesis , Quorum Sensing
16.
Infect Immun ; 80(11): 3985-92, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22949552

ABSTRACT

The transcription factor hypoxia-inducible factor 1 (HIF-1) has recently emerged to be a crucial regulator of the immune response following pathogen perception, including the response to the important human pathogen Pseudomonas aeruginosa. However, as mechanisms involved in HIF-1 activation by bacterial pathogens are not fully characterized, understanding how bacteria and bacterial compounds impact on HIF-1α stabilization remains a major challenge. In this context, we have focused on the effect of secreted factors of P. aeruginosa on HIF-1 regulation. Surprisingly, we found that P. aeruginosa cell-free supernatant significantly repressed HIF-1α protein levels. Further characterization revealed that HIF-1α downregulation was dependent on a subset of key secreted factors involved in P. aeruginosa pathogenesis, the 2-alkyl-4-quinolone (AQ) quorum sensing (QS) signaling molecules, and in particular the pseudomonas quinolone signal (PQS). Under hypoxic conditions, the AQ-dependent downregulation of HIF-1α was linked to the suppressed induction of the important HIF-1 target gene hexokinase II. Furthermore, we demonstrated that AQ molecules directly target HIF-1α protein degradation through the 26S-proteasome proteolytic pathway but independently of the prolyl hydroxylase domain (PHD). In conclusion, this is the first report showing that bacterial molecules can repress HIF-1α protein levels. Manipulation of HIF-1 signaling by P. aeruginosa AQs could have major consequences for the host response to infection and may facilitate the infective properties of this pathogen.


Subject(s)
4-Quinolones/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Hypoxia-Inducible Factor 1/metabolism , Pseudomonas aeruginosa/metabolism , Blotting, Western , Cells, Cultured , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Real-Time Polymerase Chain Reaction , Signal Transduction/physiology
17.
J Cyst Fibros ; 10(4): 286-90, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21420913

ABSTRACT

The continuous infection-inflammation cycle plays a crucial role in the progression of cystic fibrosis (CF) disease. This noxious loop can be aggravated by a reduced partial pressure of oxygen in the blood, hypoxemia, present in CF patients. These interconnected factors, hypoxia, inflammation and infection, by stabilizing the hypoxia-inducible factor-1α (HIF-1α) protein subunit, are able to activate the transcription factor HIF-1. To date, data investigating the potential role of HIF-1 in CF are scarce. Our results demonstrated that HIF-1α protein expression was altered in CF-affected compared to CFTR-corrected airway epithelial cells in unsimulated and simulated hypoxic conditions. In contrast, when CF-affected cells were infected with Pseudomonas aeruginosa, HIF-1α was more stabilized compared to CFTR-corrected cells. As HIF-1 is linked with an efficient immune response and pulmonary complications in cystic fibrosis, this difference in HIF-1α protein levels could have an impact in the CF pathology and the persistence of P. aeruginosa infection.


Subject(s)
Cystic Fibrosis/metabolism , Cystic Fibrosis/physiopathology , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Respiratory Mucosa/metabolism , Bronchi/cytology , Cell Line , Cystic Fibrosis/microbiology , Humans , Hypoxia/metabolism , Hypoxia/physiopathology , Pseudomonas Infections/metabolism , Pseudomonas Infections/physiopathology , Pseudomonas aeruginosa , Respiratory Mucosa/cytology
18.
PLoS One ; 6(2): e16409, 2011 Feb 09.
Article in English | MEDLINE | ID: mdl-21347399

ABSTRACT

BACKGROUND: In 1986, two Canadian geneticists had demonstrated that Joseph Merrick, better known as the Elephant Man, suffered from the Proteus syndrome and not from neurofibromatosis type 1 (NF1), as was alleged by dermatologist Parkes in 1909. Despite this and although the two diseases differ at several levels: prevalence, diagnostic criteria, clinical manifestations and transmission, the confusion between NF1 and the "elephant man's" disease continues in medical and social representations by current linguistic usage, and in some media reports. With this article, we want to 1) document the persistence and extent of this fallacy, 2) identify certain critical factors that contribute to its persistence, and 3) evaluate its impact on the health and well being of patients with NF1 and their family members. METHODOLOGY: Participant observation in the course of an ethnographic study on intergenerational dialogue between individuals with neurofibromatosis and their parents - Analysis of the scientific literature and of pinpoint articles in the print and online news media. FINDINGS: Our findings show that because physicians have little knowledge about NF1, several print and online news media and a lot of physicians continue to make the confusion between NF1 and the disease the "elephant man". This misconception contributes to misinformation about the disease, feeding prejudices against affected patients, exacerbating the negative impacts of the disease on their quality of life, their cognitive development, their reproductive choices, as well as depriving them of proper care and appropriate genetic counseling. CONCLUSION: If family physicians and pediatricians were properly informed about the disease, they could refer their patients with NF1 to NF clinics and to specialists. Thus, patients and their family members would benefit from better-tailored clinical management of their cases, perhaps even optimal management. [corrected]


Subject(s)
Confusion , Documentation , Neurofibromatosis 1/psychology , Proteus Syndrome/psychology , Anthropology, Cultural , Family/psychology , Female , Humans , Literature , Male , Mass Media , Perception , Societies, Medical
19.
J Am Board Fam Med ; 24(1): 112-4, 2011.
Article in English | MEDLINE | ID: mdl-21209351

ABSTRACT

BACKGROUND: during informal interviews in the course of an ethnographic study on intergenerational dialogue between individuals with neurofibromatosis and their parents, many members of Canadian neurofibromatosis associations have stated that they continue to be told the condition that afflicts them or their children is "elephant man's disease." Today, even though well-established clinical criteria make it possible to diagnose and differentiate the 2 diseases, the confusion between neurofibromatosis type 1 (NF1) and elephant man's disease persists in both the media's and physicians' representations. METHODS: this was an ethnographic study in medical anthropology. DISCUSSION: some reference sources and print and online news media have all contributed to the persistence of the association between NF1 and elephant man's disease. Our observations suggest that confusing NF1 with the Elephant Man's condition harms the interests of those with NF1 and thus increases the burden of the disease. CONCLUSION: changes of attitude regarding medical teaching and the media could dispel the confusion among physicians and journalists.


Subject(s)
Diagnostic Errors , Neurofibromatosis 1/diagnosis , Proteus Syndrome/diagnosis , Anthropology, Cultural , Humans , Names , Neurofibromatosis 1/genetics , Neurofibromatosis 1/pathology , Proteus Syndrome/genetics , Proteus Syndrome/pathology
20.
BMC Health Serv Res ; 10: 298, 2010 Oct 29.
Article in English | MEDLINE | ID: mdl-21034483

ABSTRACT

BACKGROUND: For the treatment of chronic back pain, it has been theorized that integrative care plans can lead to better outcomes than those achieved by monodisciplinary care alone, especially when using a collaborative, interdisciplinary, and non-hierarchical team approach. This paper describes the use of a care pathway designed to guide treatment by an integrative group of providers within a randomized controlled trial. METHODS: A clinical care pathway was used by a multidisciplinary group of providers, which included acupuncturists, chiropractors, cognitive behavioral therapists, exercise therapists, massage therapists and primary care physicians. Treatment recommendations were based on an evidence-informed practice model, and reached by group consensus. Research study participants were empowered to select one of the treatment recommendations proposed by the integrative group. Common principles and benchmarks were established to guide treatment management throughout the study. RESULTS: Thirteen providers representing 5 healthcare professions collaborated to provide integrative care to study participants. On average, 3 to 4 treatment plans, each consisting of 2 to 3 modalities, were recommended to study participants. Exercise, massage, and acupuncture were both most commonly recommended by the team and selected by study participants. Changes to care commonly incorporated cognitive behavioral therapy into treatment plans. CONCLUSION: This clinical care pathway was a useful tool for the consistent application of evidence-based care for low back pain in the context of an integrative setting. TRIAL REGISTRATION: ClinicalTrials.gov NCT00567333.


Subject(s)
Critical Pathways , Integrative Medicine/organization & administration , Low Back Pain/therapy , Patient Care Team/organization & administration , Benchmarking , Chronic Disease , Disease Management , Evidence-Based Medicine , Female , Humans , Integrative Medicine/education , Interprofessional Relations , Male , Outcome and Process Assessment, Health Care
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