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1.
Chem Soc Rev ; 47(14): 5187-5233, 2018 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-29901663

RESUMEN

After about three decades of development, the polyol process is now widely recognized and practised as a unique soft chemical method for the preparation of a large variety of nanoparticles which can be used in important technological fields. It offers many advantages: low cost, ease of use and, very importantly, already proven scalability for industrial applications. Among the different classes of inorganic nanoparticles which can be prepared in liquid polyols, metals were the first reported. This review aims to give a comprehensive account of the strategies used to prepare monometallic nanoparticles and multimetallic materials with tailored size and shape. As regards monometallic materials, while the preparation of noble as well as ferromagnetic metals is now clearly established, the scope of the polyol process has been extended to the preparation of more electropositive metals, such as post-transition metals and semi-metals. The potential of this method is also clearly displayed for the preparation of alloys, intermetallics and core-shell nanostructures with a very large diversity of compositions and architectures.

2.
Exp Physiol ; 103(1): 1-8, 2018 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-29094480

RESUMEN

NEW FINDINGS: What is the central question of this study? Although peripheral blood haematopoietic stem and progenitor cells are potentially important in regeneration after acute myocardial infarction, their self-renewal ability in the post-acute phase has not yet been addressed. What is the main finding and its importance? In rat peripheral blood, we show that myocardial infarction does not negatively affect circulating haematopoietic stem and progenitor cell self-renewal ability 2 weeks after acute infarction, which suggests a constant regenerative potential in the myocardial infarction post-acute phase. Given the importance of peripheral blood haematopoietic stem and progenitor cells (HPCs) in post-acute regeneration after acute myocardial infarction (MI), the aim of the present study was to investigate the number and secondary replating capacity/self-renewal ability of HPCs in peripheral blood before and 2 weeks after MI. In female Lewis inbred rats (n = 9), MI was induced by ligation of the left coronary artery, and another nine underwent sham surgery, without ligation, for control purposes. Myocardial infarction was confirmed by troponin I concentrations 24 h after surgery. Peripheral blood was withdrawn and fractional shortening and ejection fraction of the left ventricle were assessed before (day 0) and 14 days after MI or sham surgery (day 14). After mononuclear cell isolation, primary and secondary functional colony-forming unit granulocyte-macrophage (CFU-GM) assays were performed in order to detect the kinetics of functional HPC colony counts and cell self-renewal ability in vitro. The CFU-GM counts and cell self-renewal ability remained unchanged (P > 0.05) in both groups at day 14, without interaction between groups. In the intervention group, higher day 0 CFU-GM counts showed a relationship to lower fractional shortening on day 14 (ρ = -0.82; P < 0.01). Myocardial infarction did not negatively affect circulating HPC self-renewal ability, which suggests a constant regenerative potential in the post-acute phase. A relationship of cardiac contractile function 14 days after MI with circulating CFU-GM counts on day 0 might imply functional colony count as a predictive factor for outcome after infarction.


Asunto(s)
Autorrenovación de las Células/fisiología , Modelos Animales de Enfermedad , Células Madre Hematopoyéticas/fisiología , Infarto del Miocardio/sangre , Infarto del Miocardio/fisiopatología , Animales , Separación Celular/métodos , Femenino , Ratas , Ratas Endogámicas Lew
3.
Platelets ; 29(3): 316-318, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29119855

RESUMEN

Bernard-Soulier syndrome (BSS) is an autosomal recessive major thrombocytopathy, the symptoms of which are mainly marked by mucocutaneous bleeding. This rare disease, initially described in the 1970s, is the result of an abnormal formation of the glycoprotein complex Ib-IX-V (GP Ib-IX-V), a platelet receptor of von Willebrand factor. A large number of mutations, sometimes involving the GP9 gene, have been described as possibly responsible for the disease. We report here the case of a BSS patient who presented with persistent thrombocytopenia (31x109/L) and decreased surface expression of GPIb-IX-V on large platelets with anisocytosis. Thorough molecular analyses disclosed two previously unreported GP9 variants, respectively c.230T>A (p.Leu77Gln) and c.255C>A (p.Asn85Lys). Both are likely to modify the conformation of GP-IX interactions with other glycoproteins of the Ib-IX-V complex and thus proper expression of this complex on the membrane of platelets.


Asunto(s)
Síndrome de Bernard-Soulier/diagnóstico , Síndrome de Bernard-Soulier/genética , Variación Genética , Complejo GPIb-IX de Glicoproteína Plaquetaria/genética , Alelos , Síndrome de Bernard-Soulier/sangre , Biomarcadores , Preescolar , Biología Computacional/métodos , Femenino , Estudios de Asociación Genética , Genotipo , Humanos , Modelos Moleculares , Mutación , Fenotipo , Complejo GPIb-IX de Glicoproteína Plaquetaria/química , Conformación Proteica , Análisis de Secuencia de ADN , Relación Estructura-Actividad
4.
Clin Genet ; 79(4): 371-7, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20569257

RESUMEN

Pre-axial polydactyly type II (PPDII, MIM #174500), Werner mesomelic syndrome (MIM %188770) and Haas polysyndactyly (MIM #186200) are a group of closely related conditions caused by mutations in a long-range Sonic hedgehog (SHH, MIM *600725) regulator called ZRS. To date, 19 point mutations, 10 duplications and 1 triplication of the ZRS associated with those pre-axial polydactylies have been reported in humans, mice, cats and chickens. Some of these have been shown to cause ectopic expression of Shh in the limb bud in mice, leading to a polydactylous phenotype, but the precise mechanism by which ZRS mutations generate this phenotype remains unknown. We present two PPDII families with fully penetrant point mutations in ultra-conserved predicted binding sites for transcription factors SOX9 and PAX3, two possible candidates for regulating SHH expression. Screening for point mutations or copy-number variation of the ZRS, high-resolution array-CGH, and screening of other conserved non-coding sequences (CNS) surrounding SHH in a third family are negative. This is the sixth PPDII pedigree with possible linkage to 7q36 that presents with no detectable ZRS mutation. We hypothesize that another nearby regulatory sequence, or an undetected position effect between ZRS and SHH, could be responsible for negative familial cases linked to 7q36.


Asunto(s)
Predisposición Genética a la Enfermedad/genética , Proteínas Hedgehog/genética , Mutación , Polidactilia/genética , Animales , Secuencia de Bases , Sitios de Unión/genética , Análisis Mutacional de ADN , Salud de la Familia , Humanos , Datos de Secuencia Molecular , Factor de Transcripción PAX3 , Factores de Transcripción Paired Box/genética , Linaje , Mutación Puntual , Factor de Transcripción SOX9/genética , Homología de Secuencia de Aminoácido
5.
Nat Med ; 1(2): 154-8, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7585013

RESUMEN

The molecular basis of the injurious actions of non-steroidal anti-inflammatory drugs (NSAIDs) on the gastrointestinal (GI) tract is only partly understood. In this study we have obtained evidence, employing both in vitro and in vivo systems, that five NSAIDs have the ability to form a chemical association with zwitterionic phospholipids. Since this same class of phospholipids line the luminal aspects of the mucus gel layer to provide it with non-wettable properties, this intermolecular association may be the mechanism by which NSAIDs attenuate the hydrophobic barrier properties of the upper GI tract. Preassociating a number of NSAIDs with exogenous zwitterionic phospholipids prevented this increase in surface wettability of the mucus gel layer and protected rats against the injurious GI side-effects of these drugs, while enhancing their lipid permeability, antipyretic and anti-inflammatory activity.


Asunto(s)
1,2-Dipalmitoilfosfatidilcolina/efectos adversos , Antiinflamatorios no Esteroideos/efectos adversos , Úlcera Péptica/inducido químicamente , Fosfatidilcolinas/efectos adversos , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/metabolismo , Fiebre/tratamiento farmacológico , Granuloma/tratamiento farmacológico , Masculino , Permeabilidad , Fosfatidilcolinas/metabolismo , Ratas , Ratas Sprague-Dawley , Solubilidad , Solventes , Humectabilidad
6.
Rev Med Interne ; 42(6): 384-391, 2021 Jun.
Artículo en Francés | MEDLINE | ID: mdl-33678447

RESUMEN

INTRODUCTION: Immune monitoring of monoclonal antibodies is a helpful tool in optimizing the management of patients treated with TNF blockers, especially in gastroenterology. In contrast, studies evaluating the interest of such monitoring are lacking for other monoclonal antibodies used in autoimmune diseases, including rituximab despite its widespread use in the field for almost 15 years. Hence, we conducted a study whose goal was to describe the clinical and biological characteristics of all patients who had a rituximab immune monitoring. METHODS: All the clinical, biological and therapeutic data attached to the demands (from 2015 onwards) we received for immune monitoring of rituximab (measurements of rituximab serum levels and anti-rituximab antibodies using the drug-sensitive assay LISA-TRACKER Duo Rituximab®), were retrospectively reviewed. Suspected cases of hypersensitivity and secondary non-response were included. RESULTS: Several medical specialities (nephrology, haematology, neurology, rheumatology, internal medicine) were represented among the 18 records included in the study (out of 23 demands), 10 being suspected cases of hypersensitivity and 8 secondary non-responders. All 6 patients whose symptoms were consistent with the classical presentation of serum sickness, as well as half of the secondary non-responders, were positive for antirituximab antibodies. CONCLUSION: This detailed real world case study illustrates the potential benefits of rituximab immune monitoring (especially anti-rituximab antibodies) in autoimmune diseases, suggesting it could be helpful in suspected cases of serum sickness, as well as secondary non-response (B-cell non-depletion being an early red flag). Larger and disease-specific studies are warranted to support these findings.


Asunto(s)
Enfermedades Autoinmunes , Factores Inmunológicos , Anticuerpos Monoclonales , Enfermedades Autoinmunes/diagnóstico , Enfermedades Autoinmunes/tratamiento farmacológico , Enfermedades Autoinmunes/epidemiología , Humanos , Estudios Retrospectivos , Rituximab/uso terapéutico
7.
Exp Physiol ; 95(1): 131-9, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19700519

RESUMEN

Chronic anaemia increases the workload of the growing fetal heart, leading to cardiac enlargement. To determine which cellular process increases cardiac mass, we measured cardiomyocyte sizes, binucleation as an index of terminal differentiation, and tissue volume fractions in hearts from control and anaemic fetal sheep. Fourteen chronically catheterized fetal sheep at 129 days gestation had blood withdrawn for 9 days to cause severe anaemia; 14 control fetuses were of similar age. At postmortem examination, hearts were either enzymatically dissociated or fixed for morphometric analysis. Daily isovolumetric haemorrhage reduced fetal haematocrit from a baseline value of 35% to 15% on the final day (P < 0.001). At the study conclusion, anaemic fetuses had lower arterial pressures than control fetuses (P < 0.05). Heart weights were increased by 39% in anaemic fetuses compared with control hearts (P < 0.0001), although the groups had similar body weights; the heart weight difference was not due to increased ventricular wall water content or disproportionate non-myocyte tissue expansion. Cardiomyocytes from anaemic fetuses tended to be larger than those of control fetuses. There were no statistically significant differences between groups in the cardiomyocyte cell cycle activity. The degree of terminal differentiation was greater in the right ventricle of anaemic compared with control fetuses by 8% (P < 0.05). Anaemia substantially increased heart weight in fetal sheep. The volume proportions of connective and vascular tissue were unchanged. Cardiomyocyte mass expanded by a balanced combination of cellular enlargement, increased terminal differentiation and accelerated proliferation.


Asunto(s)
Anemia/patología , Aumento de la Célula , Proliferación Celular , Modelos Animales de Enfermedad , Enfermedades Fetales/patología , Miocitos Cardíacos/patología , Anemia/sangre , Animales , Enfermedad Crónica , Femenino , Enfermedades Fetales/sangre , Miocitos Cardíacos/metabolismo , Embarazo , Ovinos
8.
Euro Surveill ; 13(22)2008 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-18761959

RESUMEN

In November 2006, six symptomatic cases of hepatitis A in pupils of a secondary school in Upper Normandy, France, were reported to the district health service. This paper describes the outbreak investigation undertaken with the aim to identify the vehicle and source of infection, implement control measures and estimate the size of the outbreak. A primary case at the secondary school was defined as a pupil or a member of the staff with IgM anti-HAV detected in the serum and with onset of symptoms between 12 and 21 November 2006; a secondary case was defined as a contact to a primary case and who developed symptoms and had IgM anti-HAV two to seven weeks later. We performed a case control study of primary cases, controls being pupils visiting the same school (cases/controls 1:4) and inspected the canteen facilities. All 13 canteen employees were examined for anti-HAV IgM antibodies. A phylogenetic analysis of HAV of cases was performed. We identified 10 primary and 5 secondary cases. Among primary cases 90% reported eating liver pate at the canteen compared to 62% among controls (OR 5.5, 95% CI 0.62-256.9). One liver pate sample contained markers of faecal contamination. HAV genotypes were of one identical type. All 13 canteen employees were negative for IgM anti-HAV while four had anti-HAV total antibodies. We found deficiencies regarding food preparing procedures and insufficient hand washing facilities. The vehicle of the outbreak was believed to be the liver pate but the source of HAV could not be identified. Insufficient facilities in the canteen hindered staff from maintaining a high hygiene standard and were subsequently improved.


Asunto(s)
Brotes de Enfermedades/estadística & datos numéricos , Contaminación de Alimentos/estadística & datos numéricos , Hepatitis A/epidemiología , Vigilancia de la Población , Medición de Riesgo/métodos , Instituciones Académicas/estadística & datos numéricos , Adolescente , Adulto , Femenino , Francia/epidemiología , Humanos , Incidencia , Masculino , Factores de Riesgo
9.
Curr Opin Struct Biol ; 10(6): 687-96, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11114506

RESUMEN

L-Rhamnose is a deoxy sugar found widely in bacteria and plants. Evidence continues to emerge about its essential role in many pathogenic bacteria. The crystal structures of two of the four enzymes involved in its biosynthetic pathway have been reported and the other two have been submitted for publication. This pathway does not exist in humans, making enzymes of this pathway very attractive targets for therapeutic intervention.


Asunto(s)
Ramnosa/metabolismo , Cristalografía por Rayos X , Enzimas/química , Enzimas/metabolismo , Conformación Proteica , Ramnosa/biosíntesis
10.
J Radiol ; 88(1 Pt 1): 11-25, 2007 Jan.
Artículo en Francés | MEDLINE | ID: mdl-17299363

RESUMEN

Magnetic resonance (MR) imaging of the pancreas has undergone a major change because it can provide noninvasive images of the pancreatic ducts and the parenchyma. MR cholangiopancreatography (MRCP) enables detection of anatomic variants such as pancreas divisum. Although contrast material-enhanced CT is still considered the gold standard in acute pancreatitis and for the detection of calcifications in chronic pancreatitis, MR imaging and secretin-enhanced MRCP are useful in evaluating pseudocysts and pancreatic disruption. The role of MR is still debated in pancreatic neoplasms except the cystic lesions where MR imaging provides critical information regarding the lesion's content and a possible communication with the pancreatic ducts. MRCP and MR of the pancreas are also useful in identifying other pancreatic diseases such as lymphoplasmocytic pancreatitis and groove pancreatitis.


Asunto(s)
Imagen por Resonancia Magnética , Enfermedades Pancreáticas/diagnóstico , Enfermedad Aguda , Humanos , Páncreas/anomalías , Páncreas/patología , Neoplasias Pancreáticas/diagnóstico , Pancreatitis/diagnóstico
11.
J Food Prot ; 69(11): 2703-11, 2006 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17133815

RESUMEN

The effectiveness of a formulated product of the yeast Candida sake CPA-1 for controlling postharvest diseases on pome fruits was demonstrated in laboratory, semicommercial, and commercial trials carried out in the major pome fruit producing region of the European Union. First, one wettable powder and seven liquid formulations were tested in laboratory trials that involved two varieties of apples and two varieties of pears. In all cases, an efficacy similar to that of fresh cells was demonstrated in the control of artificial Penicillium expansum infection. After these trials, the formulated product chosen for semicommercial and commercial trials was LF1, a liquid formulation that is particularly suitable for commercial applications. In semicommercial trials, LF1 showed a performance similar to fresh cells in most trials, and the population dynamics of both fresh and formulated cells were quite stable throughout the storage period. This indicates the high viability of C. sake CPA-1 in this formulation and the absence of adverse effects during the formulation of the product, which may significantly affect both its ability to grow on fruit and its antagonistic activity. We evaluated the control of natural infection after applying the formulated product in a commercial drencher in different packinghouses. A significant reduction in the incidence of diseases was observed with a recommended dose of around 10(7) CFU/ml when natural infections were greater than 1%. In general, large quantities of yeast were observed on the surface of unwounded fruits of different pome fruit cultivars. Moreover, populations of this biocontrol agent increased rapidly on fruit surfaces and remained quite stable for a long time under commercial storage conditions. Commercial practices used in packinghouses were therefore successfully applied for this formulated product.


Asunto(s)
Candida/fisiología , Conservación de Alimentos/métodos , Frutas/microbiología , Penicillium/crecimiento & desarrollo , Control Biológico de Vectores , Antibiosis , Recuento de Colonia Microbiana , Microbiología de Alimentos , Frutas/normas , Región Mediterránea
12.
J Mol Biol ; 307(1): 283-95, 2001 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-11243820

RESUMEN

l-Rhamnose is a 6-deoxyhexose that is found in a variety of different glycoconjugates in the cell walls of pathogenic bacteria. The precursor of l-rhamnose is dTDP-l-rhamnose, which is synthesised from glucose- 1-phosphate and deoxythymidine triphosphate (dTTP) via a pathway requiring four enzymes. Significantly this pathway does not exist in humans and all four enzymes therefore represent potential therapeutic targets. dTDP-D-glucose 4,6-dehydratase (RmlB; EC 4.2.1.46) is the second enzyme in the dTDP-L-rhamnose biosynthetic pathway. The structure of Salmonella enterica serovar Typhimurium RmlB had been determined to 2.47 A resolution with its cofactor NAD(+) bound. The structure has been refined to a crystallographic R-factor of 20.4 % and an R-free value of 24.9 % with good stereochemistry.RmlB functions as a homodimer with monomer association occurring principally through hydrophobic interactions via a four-helix bundle. Each monomer exhibits an alpha/beta structure that can be divided into two domains. The larger N-terminal domain binds the nucleotide cofactor NAD(+) and consists of a seven-stranded beta-sheet surrounded by alpha-helices. The smaller C-terminal domain is responsible for binding the sugar substrate dTDP-d-glucose and contains four beta-strands and six alpha-helices. The two domains meet to form a cavity in the enzyme. The highly conserved active site Tyr(167)XXXLys(171) catalytic couple and the GlyXGlyXXGly motif at the N terminus characterise RmlB as a member of the short-chain dehydrogenase/reductase extended family. The quaternary structure of RmlB and its similarity to a number of other closely related short-chain dehydrogenase/reductase enzymes have enabled us to propose a mechanism of catalysis for this important enzyme.


Asunto(s)
Hidroliasas/química , NAD/química , Salmonella enterica/química , Secuencia de Aminoácidos , Sitios de Unión , Catálisis , Cristalografía por Rayos X , Hidroliasas/metabolismo , Datos de Secuencia Molecular , Azúcares de Nucleósido Difosfato/metabolismo , Nucleótidos/química , Conformación Proteica , Salmonella enterica/metabolismo , Homología de Secuencia de Aminoácido , Serotipificación , Nucleótidos de Timina/metabolismo
14.
J Radiol ; 86(6 Pt 2): 781-94; quiz 795-6, 2005 Jun.
Artículo en Francés | MEDLINE | ID: mdl-16142072

RESUMEN

IPMTP is a pancreatic duct disease that can better be diagnosed due to advances in imaging techniques. This probably explains the recent increased frequency of this disease. Enlargement of the main pancreatic duct and/or branch ducts is a typical feature. CT and MRI with MRCP are useful for diagnosis. Features of malignant degeneration are better known. Preoperative staging is performed at CT. Differential diagnosis includes main pancreatic duct dilatation and pancreatic cysts. Recent papers indicate that isolated side branch IPMTP is less frequently malignant. Surgery is indicated in the presence of acute pancreatitis or suspicion of malignant degeneration. Imaging is useful for the follow up of patients with isolated side branch IPMTP. In this paper, the diagnostic, staging and malignant features of IPMTP will be reviewed.


Asunto(s)
Carcinoma Ductal Pancreático/diagnóstico , Diagnóstico por Imagen , Neoplasias Pancreáticas/diagnóstico , Diagnóstico Diferencial , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X
15.
Nanoscale ; 7(34): 14515-24, 2015 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-26260342

RESUMEN

In the fight against antibiotic resistance, gold nanoparticles (AuNP) with antibiotics grafted on their surfaces have been found to be potent agents. Ampicillin-conjugated AuNPs have been thus reported to overcome highly ampicillin-resistant bacteria. However, the structure at the atomic scale of these hybrid systems remains misunderstood. In this paper, the structure of the interface between an ampicillin molecule AMP and three flat gold facets Au(111), Au(110) and Au(100) has been investigated with numerical simulations (dispersion-corrected DFT). Adsorption energies, bond distances and electron densities indicate that the adsorption of AMP on these facets goes through multiple partially covalent bonding. The stability of the AuNP/AMP nanoconjugates is explained by large adsorption energies and their potential antibacterial activity is discussed on the basis of the constrained spatial orientation of the grafted antibiotic.


Asunto(s)
Ampicilina/química , Antibacterianos/química , Oro/química , Nanoconjugados/química , Adsorción , Ampicilina/farmacología , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Nanopartículas del Metal/química , Propiedades de Superficie , Termodinámica
16.
Oncogenesis ; 4: e161, 2015 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-26214578

RESUMEN

Adrenocortical cancer (ACC) is a very aggressive tumor, and genomics studies demonstrate that the most frequent alterations of driver genes in these cancers activate the Wnt/ß-catenin signaling pathway. However, the adrenal-specific targets of oncogenic ß-catenin-mediating tumorigenesis have not being established. A combined transcriptomic analysis from two series of human tumors and the human ACC cell line H295R harboring a spontaneous ß-catenin activating mutation was done to identify the Wnt/ß-catenin targets. Seven genes were consistently identified in the three studies. Among these genes, we found that AFF3 mediates the oncogenic effects of ß-catenin in ACC. The Wnt response element site located at nucleotide position -1408 of the AFF3 transcriptional start sites (TSS) mediates the regulation by the Wnt/ß-catenin signaling pathway. AFF3 silencing decreases cell proliferation and increases apoptosis in the ACC cell line H295R. AFF3 is located in nuclear speckles, which play an important role in RNA splicing. AFF3 overexpression in adrenocortical cells interferes with the organization and/or biogenesis of these nuclear speckles and alters the distribution of CDK9 and cyclin T1 such that they accumulate at the sites of AFF3/speckles. We demonstrate that AFF3 is a new target of Wnt/ß-catenin pathway involved in ACC, acting on transcription and RNA splicing.

17.
Free Radic Biol Med ; 16(6): 801-9, 1994 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8070684

RESUMEN

A new class of 2,5 dimethylpyrrole functionalized amino acid and peptide antioxidants has been synthesized. Pulse radiolysis studies have been carried out on these compounds to determine their reactivity in one-electron oxidation reactions with Br2- and (SCN)2-, as well as their reactivity toward the water radicals .OH and eaq-. When compared to similar reactions with parent amino acids and peptides, both rate constants and transient spectra indicate considerable interaction between the electronic states of the pyrrole moiety and amino acid or peptide. Where comparison data is available, radical reactions are significantly more rapid with these derivatives than with the parent compounds. Exceptions occur in some cases of .OH attack where steric hindrance may be evoked to explain a lower rate constant in the derivative compounds. Electron attachment rates are also found to be enhanced by the presence of the pyrrole ring.


Asunto(s)
Aminoácidos/química , Antioxidantes/química , Radical Hidroxilo , Pirroles/química , Cinética , Estructura Molecular , Oxidación-Reducción , Radiólisis de Impulso , Espectrofotometría , Relación Estructura-Actividad , Factores de Tiempo
18.
Neurology ; 57(9): 1555-60, 2001 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-11706089

RESUMEN

BACKGROUND: MG is an autoimmune disease of the neuromuscular junction. MG with thymus hyperplasia has been associated with, but not genetically linked to, the HLA-DR3 haplotype. OBJECTIVE: To re-evaluate the association of HLA with MG in 656 patients with generalized disease and to test linkage of HLA to MG with thymus hyperplasia. METHOD: Patients were genotyped for HLA-DRB1. Data analysis included case-control comparisons after subgrouping patients by thymus histopathology. The transmission of parental alleles to MG offspring with thymus hyperplasia was studied in simplex families using the transmission/disequilibrium test (TDT) as a test of linkage. RESULTS: MG with thymus hyperplasia was positively associated with DR3 (OR = 4.5, p = 1 x 10(-6)) and negatively associated with DR7 (OR = 0.28, p = 1 x 10(-6)), based on both case-control comparisons and TDT. No association was detected with thymomas. Conversely, patients who lacked thymus anomalies but expressed anti-titin antibodies (ATA) had an increase of DR7 (OR = 2.08, p = 4 x 10(-3)) and a decrease of DR3 (OR = 0.33, p = 9 x 10(-3)). CONCLUSIONS: The authors established linkage of HLA to MG and thymus hyperplasia, defining the MYAS1 locus. Moreover, DR3 and DR7, or closely linked genes, have opposing effects on MG phenotypes. Nonthymomatous patients with ATA may be a pathogenetically distinct subset of MG patients.


Asunto(s)
Antígeno HLA-DR3/genética , Desequilibrio de Ligamiento , Proteínas Musculares/inmunología , Miastenia Gravis/genética , Miastenia Gravis/inmunología , Proteínas Quinasas/inmunología , Adulto , Autoanticuerpos/análisis , Estudios de Casos y Controles , Conectina , Femenino , Heterogeneidad Genética , Genotipo , Antígenos HLA-DR/genética , Cadenas HLA-DRB1 , Humanos , Masculino , Miastenia Gravis/patología , Fenotipo , Timo/patología , Hiperplasia del Timo/genética , Hiperplasia del Timo/inmunología , Hiperplasia del Timo/patología
19.
Biochem Pharmacol ; 57(3): 247-54, 1999 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-9890551

RESUMEN

The possibility that the molecular mechanism underlying the topical gastric irritancy of nonsteroidal anti-inflammatory drugs (NSAIDs) may involve alterations in the surface-active properties of gastric phospholipids was investigated. Indomethacin and naproxen were intragastrically administered to rats and the hydrophobicity of the luminal surface of the stomach wall was assessed by contact angle analysis. Both NSAIDs have the ability to attenuate the phospholipid-related hydrophobic properties of the gastric mucosa by more than 80-85% in a dose-dependent fashion. Potential molecular interactions between both NSAIDs and surface-active phospholipids were analyzed using fluorescent probes. Indomethacin has the ability to displace, in a dose-dependent manner, ANS (1-anilino-8-naphthalene sulphonate), a fluorescent anionic probe previously bound to the head group of phosphatidylcholine molecules. Estimations of the resonance fluorescence transfer between naproxen and the surface probe ANS or the hydrophobic probe, pyrene, bound to dipalmitoylphosphatidylcholine (DPPC) vesicles revealed that naproxen diffuses within the phospholipid bilayers. The dynamic of the gastric lipid material extracted from the surface scraping material (SSM) of the mucosa was altered by the NSAID as shown by the increase in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) (at 25 degrees, rSSM = 0.106+/-0.006, rssM + indomethacin = 0.137+/-0.005, and rSSM + naproxen = 0.133+/-0.007, P < 0.001). The thermodynamic behavior of a model bilayer containing DPPC was also perturbed by the NSAIDs tested. These results provide evidence that NSAIDs may reduce the ability of gastric surface-active phospholipids to form a hydrophobic protective layer.


Asunto(s)
Antiinflamatorios no Esteroideos/metabolismo , Mucosa Gástrica/efectos de los fármacos , Indometacina/metabolismo , Naproxeno/metabolismo , Fosfolípidos/metabolismo , Tensoactivos/metabolismo , Animales , Antiinflamatorios no Esteroideos/efectos adversos , Mucosa Gástrica/metabolismo , Indometacina/efectos adversos , Liposomas , Masculino , Naproxeno/efectos adversos , Ratas , Ratas Sprague-Dawley , Solubilidad , Espectrometría de Fluorescencia , Agua/química
20.
Aliment Pharmacol Ther ; 11(5): 899-906, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9354198

RESUMEN

BACKGROUND: Treatment and prevention of non-steroidal anti-inflammatory drug-induced gastropathy involve the concurrent use of antisecretory drugs. Recently, we have shown that the ability of these drugs to increase the intragastric pH to values > > pKa of NSAIDs compromises their therapeutic activity. In the present study, we evaluated the potential of omeprazole to interfere with the bioavailability of aspirin administered to rats either alone or complexed with the zwitterionic phospholipid, dipalmitoylphosphatidylcholine (DPPC). METHODS: Aspirin or aspirin/DPPC was administered intragastrically to rats pre-dosed with either saline or omeprazole. Concentrations of aspirin and salicylic acid in the blood and the gastric mucosa were assessed by HPLC and the 6-keto-PGF1 alpha gastric mucosal concentration by radioimmunoassay. RESULTS: Gastric absorption of aspirin and its relative bioavailability were reduced by an antisecretory dose of omeprazole; its inhibitory effect on gastric prostaglandin synthesis was consequently attenuated. However, these effects could be partly overcome if aspirin was administered as a complex with DPPC. CONCLUSIONS: These observations suggest that: (i) DPPC increases the lipid solubility and gastric permeability of NSAIDs; and (ii) neutralization of the gastric pH results in a shift of aspirin absorption toward the intestine where it could be degraded to salicylic acid.


Asunto(s)
1,2-Dipalmitoilfosfatidilcolina , Antiinflamatorios no Esteroideos/farmacocinética , Aspirina/farmacocinética , Inhibidores Enzimáticos/farmacología , Omeprazol/farmacología , Inhibidores de la Bomba de Protones , 1,2-Dipalmitoilfosfatidilcolina/química , 6-Cetoprostaglandina F1 alfa/metabolismo , Administración Oral , Animales , Aspirina/sangre , Aspirina/química , Disponibilidad Biológica , Portadores de Fármacos , Mucosa Gástrica/metabolismo , Masculino , Pruebas de Neutralización , Ratas , Ratas Sprague-Dawley
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