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Medicinas Complementárias
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1.
Ann Epidemiol ; 67: 19-28, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34798296

RESUMEN

PURPOSE: To evaluate the potential of a Cox marginal structural model (MSM) to estimate the time-varying causal inference of a known clinical trial association where the effectiveness of inhaled corticosteroid- (ICS-) versus non-ICS-containing treatments has been compared in patients with chronic obstructive pulmonary disease (COPD). METHODS: This retrospective study from 2006-2016 used linked data from Clinical Practice Research Datalink-GOLD, Hospital Episode Statistics, and Office for National Statistics mortality. A Cox MSM, incorporating a new-user design, was deemed capable of replicating a clinical trial-like pathway. Repeated outcomes for exacerbation events and stabilized weights were used to include time-varying and fixed covariate exposures. RESULTS: Of 45,958 patients, 55% were male; 52% had moderate COPD. ICS-treated patients had a higher incidence of comorbid asthma than non-ICS-treated patients. Adjusted hazard risk ratios for any exacerbation event: ICS and/or long-acting ß2-agonist (LABA) versus long-acting muscarinic antagonist (LAMA), 1.07 (95% confidence interval 1.04-1.10); ICS/LABA versus LABA and/or LAMA, 1.05 (1.00-1.10); ICS and/or LABA and/or LAMA versus LAMA, 1.04 (1.01-1.06); ICS and/or LABA and/or LAMA versus LABA and/or LAMA 1.02 (0.97-1.07). CONCLUSIONS: The Cox MSM was not able to fully demonstrate results consistent with the previously established benefits of ICS-containing treatments seen in clinical trials. Future studies should continue to investigate causal inference methods and their capability to estimate the long-term outcomes of treatment in COPD.


Asunto(s)
Agonistas de Receptores Adrenérgicos beta 2 , Enfermedad Pulmonar Obstructiva Crónica , Administración por Inhalación , Corticoesteroides/uso terapéutico , Agonistas de Receptores Adrenérgicos beta 2/efectos adversos , Femenino , Humanos , Masculino , Modelos Estructurales , Antagonistas Muscarínicos/efectos adversos , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Estudios Retrospectivos
2.
Planta ; 249(6): 1823-1836, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30847571

RESUMEN

MAIN CONCLUSION: The enzymes HaKCS1 and HaKCS2 are expressed in sunflower seeds and contribute to elongation of C18 fatty acids, resulting in the C20-C24 fatty acids in sunflower oil. Most plant fatty acids are produced by plastidial soluble fatty acid synthases that produce fatty acids of up to 18 carbon atoms. However, further acyl chain elongations can take place in the endoplasmic reticulum, catalysed by membrane-bound synthases that act on acyl-CoAs. The condensing enzymes of these complexes are the ketoacyl-CoA synthase (KCSs), responsible for the synthesis of very long chain fatty acids (VLCFAs) and their derivatives in plants, these including waxes and cuticle hydrocarbons, as well as fatty aldehydes. Sunflower seeds accumulate oil that contains around 2-3% of VLCFAs and studies of the fatty acid elongase activity in developing sunflower embryos indicate that two different KCS isoforms drive the synthesis of these fatty acids. Here, two cDNAs encoding distinct KCSs were amplified from RNAs extracted from developing sunflower embryos and named HaKCS1 and HaKCS2. These genes are expressed in developing seeds during the period of oil accumulation and they are clear candidates to condition sunflower oil synthesis. These two KCS cDNAs complement a yeast elongase null mutant and when expressed in yeast, they alter the host's fatty acid profile, proving the encoded KCSs are functional. The structure of these enzymes was modelled and their contribution to the presence of VLCFAs in sunflower oil is discussed based on the results obtained.


Asunto(s)
Acetiltransferasas/metabolismo , Helianthus/enzimología , Modelos Estructurales , Aceite de Girasol/metabolismo , Acetiltransferasas/química , Acetiltransferasas/genética , Acilcoenzima A/metabolismo , Aldehídos/metabolismo , Secuencia de Aminoácidos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , ADN Complementario/genética , Ácido Graso Sintasas/química , Ácido Graso Sintasas/genética , Ácido Graso Sintasas/metabolismo , Ácidos Grasos/metabolismo , Helianthus/genética , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Semillas/enzimología , Semillas/genética , Alineación de Secuencia
3.
Planta Med ; 84(15): 1127-1133, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29689587

RESUMEN

Three new bisindole alkaloids, 3'-(2-oxopropyl)-19,20-dihydrotabernamine (1: ), 3'-(2-oxopropyl)-ervahanine B (2: ), 19,20-dihydrovobparicine (3: ), and 20 known compounds were isolated from the aerial parts of Tabernaemontana bufalina. The structures of these alkaloids were elucidated using spectroscopic methods. The absolute configurations of 1: -3: were determined by the circular dichroic exciton chirality method. Compounds 1: -23: were screened for their cytotoxicity against two human cancer cell lines, A-549 and MCF-7. Ten compounds (1: -3, 10, 14, 16, 17, 19, 22: , and 23: ) exhibited inhibitory effects against the two human cancer cells with IC50 values of 1.19 ~ 6.13 µM.


Asunto(s)
Hidrocarburos Aromáticos con Puentes/química , Alcaloides Indólicos/química , Monoterpenos/química , Tabernaemontana/química , Hidrocarburos Aromáticos con Puentes/aislamiento & purificación , Hidrocarburos Aromáticos con Puentes/farmacología , Línea Celular Tumoral , Humanos , Alcaloides Indólicos/aislamiento & purificación , Alcaloides Indólicos/farmacología , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Modelos Estructurales , Monoterpenos/aislamiento & purificación , Monoterpenos/farmacología , Componentes Aéreos de las Plantas/química
4.
Plant Sci ; 263: 1-11, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28818364

RESUMEN

Physiological responses of plants to salinity stress requires the coordinated activation of many genes. A salt-induced gene was isolated from roots of the wild tomato species Solanum chilense and named SchRabGDI1 because it encodes a protein with high identity to GDP dissociation inhibitors of plants. These proteins are regulators of the RabGTPase cycle that play key roles in intracellular vesicular trafficking. The expression pattern of SchRabGDI1 showed an early up-regulation in roots and leaves under salt stress. Functional activity of SchRabGDI1 was shown by restoring the defective phenotype of the yeast sec19-1 mutant and the capacity of SchRabGDI1 to interact with RabGTPase was demonstrated through BiFC assays. Expression of SchRabGDI1 in Arabidopsis thaliana plants resulted in increased salt tolerance. Also, the root cells of transgenic plants showed higher rate of endocytosis under normal growth conditions and higher accumulation of sodium in vacuoles and small vesicular structures under salt stress than wild type. Our results suggest that in salt tolerant species such as S. chilense, bulk endocytosis is one of the early mechanisms to avoid salt stress, which requires the concerted expression of regulatory genes involved in vesicular trafficking of the endocytic pathway.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Inhibidores de Disociación de Guanina Nucleótido/metabolismo , Solanum/genética , Arabidopsis/genética , Arabidopsis/fisiología , Inhibidores de Disociación de Guanina Nucleótido/genética , Modelos Estructurales , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/fisiología , Brotes de la Planta/genética , Brotes de la Planta/fisiología , Transporte de Proteínas , Salinidad , Tolerancia a la Sal , Cloruro de Sodio/metabolismo , Solanum/fisiología , Estrés Fisiológico , Vesículas Transportadoras/metabolismo , Regulación hacia Arriba
5.
Eur Arch Otorhinolaryngol ; 273(8): 2027-34, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26335291

RESUMEN

It is important to have a standardized tympanic membrane (TM) perforation platform to evaluate the various myringoplasty materials that have been studied and developed extensively during recent years. However, currently there are no cellular models specifically designed for this purpose, and animal models remain unsatisfactory. The purpose of this study is to propose an inexpensive, readily available, well-controlled, and easy-to-create cellular model as a substitute for use in the evaluation of TM repairing materials. A trans-well model was created using a cell culture insert with a round hole created at the center of the polycarbonate membrane. HaCaT cells were cultured on the fenestrated culture insert, and the desired myringoplasty graft was placed at the center of the window for one week and observed by fluorescent microscopy under vital staining. Under this cellular model, there was notable migration of HaCaT cells onto the positive control graft (rabbit fascia), while only a few cell clusters were observed on the negative control graft (paper). Model validation showed that the cell migration ratio for the PLLA + 1% hyaluronic acid (HA) graft is significantly higher than using myringoplasty paper, poly L-lactide (PLLA), or PLLA + 0.5% HA (p < 0.05). This trans-well-based cellular model might be a useful pre-evaluation platform for the evaluation of TM repairing materials. The model is inexpensive, readily available, easy to create, and standardized for use.


Asunto(s)
Ácido Hialurónico/uso terapéutico , Miringoplastia , Resinas Acrílicas/uso terapéutico , Adyuvantes Inmunológicos/uso terapéutico , Animales , Técnicas de Cultivo de Célula , Fascia/trasplante , Humanos , Masculino , Ensayo de Materiales , Modelos Estructurales , Miringoplastia/instrumentación , Miringoplastia/métodos , Cemento de Policarboxilato/uso terapéutico , Conejos , Membrana Timpánica/cirugía , Perforación de la Membrana Timpánica/cirugía
6.
Afr Health Sci ; 14(4): 1056-62, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25834517

RESUMEN

BACKGROUND: Searching the drug molecules from the medicinal plants become more and more popular given that herbal components have been widely considered to be safe. In medical virtual plant studies, development rules are difficult to be extracted, the construction of plant organs is highly dependent on equipment and the process is complicated. AIM: To establish three-dimensional structural virtual plant growth model. METHODS: The quasi-binary tree structure and its properties were obtained through the research of theory on binary tree, then the relationship between quasi-binary tree structure and plant three-dimensional branching structure model was analyzed, and the three-dimensional morphology of plants was described. RESULTS: A three-dimensional plant branch structure pattern extracting algorithm based on quasi-binary tree structure. By using 3-D L-system method, the extracted rules were systematized, and standardized. Further more, we built a comprehensive L-model system. With the aid of graphics and PlantVR, we implemented the plant shape and 3-D structure's reconstruction. CONCLUSION: Three-dimensional structure virtual plant growth model based on time-controlled L-system has been successfully established.


Asunto(s)
Simulación por Computador , Modelos Biológicos , Árboles/crecimiento & desarrollo , Árboles/metabolismo , Transporte Biológico Activo , Metabolismo de los Hidratos de Carbono , Procesamiento de Imagen Asistido por Computador , Modelos Estructurales , Componentes Aéreos de las Plantas/metabolismo , Hojas de la Planta/anatomía & histología , Hojas de la Planta/fisiología , Brotes de la Planta/anatomía & histología , Brotes de la Planta/fisiología
7.
Phytomedicine ; 20(8-9): 734-42, 2013 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-23453308

RESUMEN

Plant-derived non-essential fatty acids are important dietary nutrients, and some are purported to have chemopreventive properties against various cancers, including that of the prostate. In this study, we determined the ability of seven dietary C-18 fatty acids to cause cytotoxicity and induce apoptosis in various types of human prostate cancer cells. These fatty acids included jacaric and punicic acid found in jacaranda and pomegranate seed oil, respectively, three octadecatrienoic geometric isomers (alpha- and beta-calendic and catalpic acid) and two mono-unsaturated C-18 fatty acids (trans- and cis-vaccenic acid). Jacaric acid and four of its octadecatrienoic geoisomers selectively induced apoptosis in hormone-dependent (LNCaP) and -independent (PC-3) human prostate cancer cells, whilst not affecting the viability of normal human prostate epithelial cells (RWPE-1). Jacaric acid induced concentration- and time-depedent LNCaP cell death through activation of intrinsic and extrinsic apoptotic pathways resulting in cleavage of PARP-1, modulation of pro- and antiapoptotic Bcl-2 family of proteins and increased cleavage of caspase-3, -8 and -9. Moreover, activation of a cell death-inducing signalling cascade involving death receptor 5 was observed. Jacaric acid induced apoptosis in PC-3 cells by activation of the intrinsic pathway only. The spatial conformation cis, trans, cis of jacaric and punicic acid was shown to play a key role in the increased potency and efficacy of these two fatty acids in comparison to the five other C-18 fatty acids tested. Three-dimensional conformational analysis using the PubChem Database (http://pubchem.ncbi.nlm.nih.gov) showed that the cytotoxic potency of the C-18 fatty acids was related to their degree of conformational similarity to our cytotoxic reference compound, punicic acid, based on optimized shape (ST) and feature (CT) similarity scores, with jacaric acid being most 'biosimilar' (ST(ST-opt)=0.81; CT(CT-opt)=0.45). This 3-D analysis of structural similarity enabled us to rank geoisomeric fatty acids according to cytotoxic potency, whereas a 2-D positional assessment of cis/trans structure did not. Our findings provide mechanistic evidence that nutrition-derived non-essential fatty acids have chemopreventive biological activities and Exhibit 3-D structure-activity relationships that could be exploited to develop new strategies for the prevention or treatment of prostate cancer regardless of hormone dependency.


Asunto(s)
Apoptosis/efectos de los fármacos , Ácidos Grasos/farmacología , Ácidos Linolénicos/farmacología , Lythraceae/química , Aceites de Plantas/farmacología , Neoplasias de la Próstata/tratamiento farmacológico , Proteínas Reguladoras de la Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/metabolismo , Bignoniaceae/química , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Bases de Datos de Compuestos Químicos , Relación Dosis-Respuesta a Droga , Ácidos Grasos/química , Ácidos Grasos/aislamiento & purificación , Humanos , Ácidos Linolénicos/química , Ácidos Linolénicos/aislamiento & purificación , Masculino , Modelos Estructurales , Ácidos Oléicos/química , Ácidos Oléicos/aislamiento & purificación , Ácidos Oléicos/farmacología , Aceites de Plantas/química , Aceites de Plantas/aislamiento & purificación , Semillas/química , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad , Factores de Tiempo
8.
Plant Cell ; 25(1): 270-87, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23371948

RESUMEN

Plant cell walls are comprised largely of the polysaccharides cellulose, hemicellulose, and pectin, along with ∼10% protein and up to 40% lignin. These wall polymers interact covalently and noncovalently to form the functional cell wall. Characterized cross-links in the wall include covalent linkages between wall glycoprotein extensins between rhamnogalacturonan II monomer domains and between polysaccharides and lignin phenolic residues. Here, we show that two isoforms of a purified Arabidopsis thaliana arabinogalactan protein (AGP) encoded by hydroxyproline-rich glycoprotein family protein gene At3g45230 are covalently attached to wall matrix hemicellulosic and pectic polysaccharides, with rhamnogalacturonan I (RG I)/homogalacturonan linked to the rhamnosyl residue in the arabinogalactan (AG) of the AGP and with arabinoxylan attached to either a rhamnosyl residue in the RG I domain or directly to an arabinosyl residue in the AG glycan domain. The existence of this wall structure, named ARABINOXYLAN PECTIN ARABINOGALACTAN PROTEIN1 (APAP1), is contrary to prevailing cell wall models that depict separate protein, pectin, and hemicellulose polysaccharide networks. The modified sugar composition and increased extractability of pectin and xylan immunoreactive epitopes in apap1 mutant aerial biomass support a role for the APAP1 proteoglycan in plant wall architecture and function.


Asunto(s)
Arabidopsis/química , Pared Celular/química , Mucoproteínas/química , Pectinas/química , Proteoglicanos/química , Xilanos/química , Secuencia de Aminoácidos , Anticuerpos Monoclonales/inmunología , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/aislamiento & purificación , Proteínas de Arabidopsis/metabolismo , Biomasa , Pared Celular/genética , Pared Celular/metabolismo , Epítopos , Glicoproteínas/genética , Glicoproteínas/aislamiento & purificación , Glicoproteínas/metabolismo , Modelos Estructurales , Datos de Secuencia Molecular , Mucoproteínas/genética , Mucoproteínas/inmunología , Mucoproteínas/metabolismo , Mutación , Pectinas/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Proteínas de Plantas/metabolismo , Polisacáridos/química , Polisacáridos/metabolismo , Isoformas de Proteínas , Proteoglicanos/metabolismo , Proteómica , Xilanos/metabolismo
9.
Water Res ; 47(2): 769-80, 2013 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-23200508

RESUMEN

For several pilot-scale constructed wetlands (CWs: a planted and unplanted gravel filter) and a hydroponic plant root mat (operating at two water levels), used for treating groundwater contaminated with BTEX, the fuel additive MTBE and ammonium, the hydrodynamic behavior was evaluated by means of temporal moment analysis of outlet tracer breakthrough curves (BTCs): hydraulic indices were related to contaminant mass removal. Detailed investigation of flow within the model gravel CWs allowed estimation of local flow rates and contaminant loads within the CWs. Best hydraulics were observed for the planted gravel filter (number of continuously stirred tank reactors N = 11.3, dispersion number = 0.04, Péclet number = 23). The hydroponic plant root mat revealed lower N and pronounced dispersion tendencies, whereby an elevated water table considerably impaired flow characteristics and treatment efficiencies. Highest mass removals were achieved by the plant root mat at low level: 98% (544 mg m⁻² d⁻¹), 78% (54 mg m⁻² d⁻¹) and 74% (893 mg m⁻² d⁻¹) for benzene, MTBE and ammonium-nitrogen, respectively. Within the CWs the flow behavior was depth-dependent, with the planting and the position of the outlet tube being key factors resulting in elevated flow rate and contaminant flux immediately below the densely rooted porous media zone in the planted CW, and fast bottom flow in the unplanted reference.


Asunto(s)
Contaminación Ambiental , Restauración y Remediación Ambiental/métodos , Agua Subterránea/química , Limnología/métodos , Modelos Estructurales , Contaminantes Químicos del Agua/análisis , Humedales , Benceno/análisis , Benceno/química , Carcinógenos Ambientales/análisis , Carcinógenos Ambientales/química , Carcinógenos Ambientales/metabolismo , Sedimentos Geológicos/química , Alemania , Hidroponía , Éteres Metílicos/análisis , Éteres Metílicos/química , Éteres Metílicos/metabolismo , Petróleo/análisis , Proyectos Piloto , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Poaceae/crecimiento & desarrollo , Poaceae/metabolismo , Compuestos de Amonio Cuaternario/análisis , Compuestos de Amonio Cuaternario/química , Especificidad de la Especie , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/metabolismo , Contaminación Química del Agua
10.
PLoS One ; 7(11): e49406, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23226209

RESUMEN

In a context of pesticide use reduction, alternatives to chemical-based crop protection strategies are needed to control diseases. Crop and plant architectures can be viewed as levers to control disease outbreaks by affecting microclimate within the canopy or pathogen transmission between plants. Modeling and simulation is a key approach to help analyze the behaviour of such systems where direct observations are difficult and tedious. Modeling permits the joining of concepts from ecophysiology and epidemiology to define structures and functions generic enough to describe a wide range of epidemiological dynamics. Additionally, this conception should minimize computing time by both limiting the complexity and setting an efficient software implementation. In this paper, our aim was to present a model that suited these constraints so it could first be used as a research and teaching tool to promote discussions about epidemic management in cropping systems. The system was modelled as a combination of individual hosts (population of plants or organs) and infectious agents (pathogens) whose contacts are restricted through a network of connections. The system dynamics were described at an individual scale. Additional attention was given to the identification of generic properties of host-pathogen systems to widen the model's applicability domain. Two specific pathosystems with contrasted crop architectures were considered: ascochyta blight on pea (homogeneously layered canopy) and potato late blight (lattice of individualized plants). The model behavior was assessed by simulation and sensitivity analysis and these results were discussed against the model ability to discriminate between the defined types of epidemics. Crop traits related to disease avoidance resulting in a low exposure, a slow dispersal or a de-synchronization of plant and pathogen cycles were shown to strongly impact the disease severity at the crop scale.


Asunto(s)
Modelos Biológicos , Pisum sativum/microbiología , Enfermedades de las Plantas/microbiología , Solanum tuberosum/microbiología , Aire , Ascomicetos/fisiología , Simulación por Computador , Interacciones Huésped-Patógeno , Modelos Estructurales , Pisum sativum/inmunología , Enfermedades de las Plantas/inmunología , Solanum tuberosum/inmunología
11.
Pharmacoepidemiol Drug Saf ; 21(11): 1232-9, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22996597

RESUMEN

PURPOSE: Several observational studies have indicated that vitamin D receptor activators (VDRA), including paricalcitol, are associated with greater survival in maintenance hemodialysis (MHD) patients. However, patients with higher serum parathyroid hormone, a surrogate of higher death risk, are usually given higher VDRA doses, which can lead to confounding by indication and attenuate the expected survival advantage of high VDRA doses. METHODS: We examined mortality-predictability of low (>1 but <10 µg/week) versus high (≥10 µg/week) dose of administered paricalcitol over time in a contemporary cohort of 15 442 MHD patients (age 64 ± 15 years, 55% men, 44% diabetes, 35% African-Americans) from all DaVita dialysis clinics across the USA (7/2001-6/2006 with survival follow-ups until 6/2007) using conventional Cox regression, propensity score (PS) matching, and marginal structural model (MSM) analyses. RESULTS: In our conventional Cox models and PS matching models, low dose of paricalcitol was not associated with mortality either in baseline (hazard ratio (HR): 1.03, 95% confidence interval (CI): (0.97-1.09)) and (HR: 0.99, 95%CI:(0.86-1.14)) or time-dependent (HR: 1.04, 95%CI: (0.98-1.10)) and (HR: 1.12, 95%CI: (0.98-1.28)) models, respectively. In contrast, compared to high dose of paricalcitol, low dose was associated with a 26% higher risk of mortality (HR: 1.26, 95%CI: (1.19-1.35)) in MSM. The association between dose of paricalcitol and mortality was robust in almost all subgroups of patients using MSMs. CONCLUSIONS: Higher dose of paricalcitol appears causally associated with greater survival in MHD patients. Randomized controlled trials need to verify the survival effect of paricalcitol dose in MHD patients are indicated.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Ergocalciferoles/administración & dosificación , Modelos Estructurales , Diálisis Renal/mortalidad , Anciano , Conservadores de la Densidad Ósea/uso terapéutico , Estudios de Cohortes , Relación Dosis-Respuesta a Droga , Ergocalciferoles/uso terapéutico , Femenino , Humanos , Hiperparatiroidismo Secundario/sangre , Hiperparatiroidismo Secundario/complicaciones , Hiperparatiroidismo Secundario/tratamiento farmacológico , Fallo Renal Crónico/sangre , Fallo Renal Crónico/etiología , Fallo Renal Crónico/mortalidad , Fallo Renal Crónico/terapia , Masculino , Persona de Mediana Edad , Mortalidad/tendencias , Hormona Paratiroidea/sangre , Valor Predictivo de las Pruebas , Puntaje de Propensión , Modelos de Riesgos Proporcionales , Receptores de Calcitriol/agonistas , Análisis de Supervivencia
12.
Pharmacoepidemiol Drug Saf ; 21(3): 233-40, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21786364

RESUMEN

OBJECTIVE: There is little evidence on comparative effectiveness of individual angiotensin receptor blockers (ARBs) in patients with chronic heart failure (CHF). This study compared four ARBs in reducing risk of mortality in clinical practice. METHODS: A retrospective analysis was conducted on a national sample of patients diagnosed with CHF from 1 October 1996 to 30 September 2002 identified from Veterans Affairs electronic medical records, with supplemental clinical data obtained from chart review. After excluding patients with exposure to ARBs within the previous 6 months, four treatment groups were defined based on initial use of candesartan, valsartan, losartan, and irbesartan between the index date (1 October 2000) and the study end date (30 September 2002). Time to death was measured concurrently during that period. A marginal structural model controlled for sociodemographic factors, comorbidities, comedications, disease severity (left ventricular ejection fraction), and potential time-varying confounding affected by previous treatment (hospitalization). Propensity scores derived from a multinomial logistic regression were used as inverse probability of treatment weights in a generalized estimating equation to estimate causal effects. RESULTS: Among the 1536 patients identified on ARB therapy, irbesartan was most frequently used (55.21%), followed by losartan (21.74%), candesartan (15.23%), and valsartan (7.81%). When compared with losartan, after adjusting for time-varying hospitalization in marginal structural model, candesartan (OR = 0.79, 95%CI = 0.42-1.50), irbesartan (OR = 1.17, 95%CI = 0.72-1.90), and valsartan (OR = 0.98, 95%CI = 0.45-2.14) were found to have similar effectiveness in reducing mortality in CHF patients. CONCLUSION: Effectiveness of ARBs in reducing mortality is similar in patients with CHF in everyday clinical practice.


Asunto(s)
Antagonistas de Receptores de Angiotensina/uso terapéutico , Bencimidazoles/uso terapéutico , Compuestos de Bifenilo/uso terapéutico , Insuficiencia Cardíaca , Losartán/uso terapéutico , Tetrazoles/uso terapéutico , Valina/análogos & derivados , Anciano , Antagonistas de Receptores de Angiotensina/administración & dosificación , Bencimidazoles/administración & dosificación , Compuestos de Bifenilo/administración & dosificación , Enfermedad Crónica , Factores de Confusión Epidemiológicos , Registros Electrónicos de Salud , Femenino , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/mortalidad , Hospitalización/estadística & datos numéricos , Humanos , Irbesartán , Losartán/administración & dosificación , Masculino , Modelos Estructurales , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Riesgo , Tetrazoles/administración & dosificación , Resultado del Tratamiento , Estados Unidos , Valina/administración & dosificación , Valina/uso terapéutico , Valsartán
13.
Polim Med ; 39(1): 17-30, 2009.
Artículo en Polaco | MEDLINE | ID: mdl-19580170

RESUMEN

The production technology of powder cellulose (Arbocel) and microcrystaline cellulose (Vivapur) and their application in the composition of direct compression tablet mass was provided. The function of silicified microcrystaline cellulose type Prosolv in the direct compression process of dry plant extract was discussed. An analysis of the chemical structure of cellulose fiber (Vitacel) enabled determining its properties and applications in the manufacture of diet supplement, pharmaceutical and food products.


Asunto(s)
Celulosa/química , Excipientes/química , Extractos Vegetales/química , Comprimidos/química , Celulosa/síntesis química , Química Farmacéutica/métodos , Composición de Medicamentos/métodos , Modelos Estructurales , Polvos/química
14.
Planta Med ; 74(15): 1826-8, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18991208

RESUMEN

Callianthones A ( 1) and B ( 2), a pair of new isomeric alpha-tetralones, together with a known alpha-tetralone ( 3) and four known flavonoids ( 4 - 7) were isolated from the 50 % EtOH extract of Pyrola calliantha. The structures and absolute configurations of the two new isomers were established to be (2 S,4 R) - and (2 S,4 S)-2,4-dihydroxy-2,7-dimethyl-3,4-dihydronaphthalen-1(2 H)-one ( 1 and 2, respectively) on the basis of spectral analysis, including 2 D NMR, model studies, and CD spectra.


Asunto(s)
Extractos Vegetales/aislamiento & purificación , Pyrola/química , Tetralonas/aislamiento & purificación , Isomerismo , Modelos Estructurales , Estructura Molecular , Extractos Vegetales/química , Tetralonas/química
15.
Proc Inst Mech Eng H ; 222(3): 273-83, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18491697

RESUMEN

New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether-ether-ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25 x 10(6) cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm(3)/10(6) cycles, compared with 38.6 mm(3)/10(6) cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25 x 10(6) cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed-boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.


Asunto(s)
Acetábulo/patología , Óxido de Aluminio/química , Cabeza Femoral/patología , Prótesis de Cadera , Cetonas/química , Polietilenglicoles/química , Óxido de Aluminio/uso terapéutico , Benzofenonas , Materiales Biocompatibles/química , Materiales Biocompatibles/uso terapéutico , Carbono/uso terapéutico , Fibra de Carbono , Cerámica/química , Cerámica/uso terapéutico , Fricción , Prótesis de Cadera/efectos adversos , Humanos , Cetonas/uso terapéutico , Lubrificación , Ensayo de Materiales , Modelos Estructurales , Osteólisis/etiología , Osteólisis/prevención & control , Polietilenglicoles/uso terapéutico , Polietilenos/química , Polietilenos/uso terapéutico , Polímeros , Falla de Prótesis , Propiedades de Superficie
16.
Proc Inst Mech Eng H ; 222(3): 285-96, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18491698

RESUMEN

Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic. A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt-chromium (Co-Cr) pins against Co-Cr plates; secondly, Co-Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy. The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co-Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion-wear interactions between the tribological pair.


Asunto(s)
Óxido de Aluminio/química , Artroplastia de Reemplazo de Cadera , Aleaciones de Cromo/química , Prótesis de Cadera , Ensayo de Materiales/instrumentación , Modelos Estructurales , Óxido de Aluminio/uso terapéutico , Cerámica/química , Cerámica/uso terapéutico , Aleaciones de Cromo/uso terapéutico , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/uso terapéutico , Cobalto/química , Cobalto/uso terapéutico , Corrosión , Fricción , Prótesis de Cadera/efectos adversos , Humanos , Ensayo de Materiales/métodos , Osteólisis/etiología , Osteólisis/prevención & control , Falla de Prótesis , Propiedades de Superficie
17.
J Mass Spectrom ; 42(6): 749-60, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17492721

RESUMEN

Low-energy collision-induced electrospray ionization tandem mass spectrometry ESI-CID-MS/MS (in the positive ion mode) was used for the structural characterization of a series of five representative epioplythiodioxopipreazines: dethiotetra(methylthio)chemotin, chaetocochins A, B and C, and chemotin isolated from the fungus Chaetomium cochliodes. The fragmentation pathways were elucidated by ESI-IT-MS(n). The elemental compositions of most of the product ions were confirmed by low-energy ESI-CID-QTOF-MS/MS analyses. The loss of the S(2) molecule seems always to be the first when the S--S bond is present. The loss of 77 Da corresponding to the loss of the [CH(3)SCH(2)O]' radical was diagnostic for chaetocochins A and B, in which the two piperazines rings are linked by an acetal group. It was found that a McLafferty rearrangement plays a significant role in the skeleton fragmentation of theses series of studied complex multicyclic piperazine compounds. This MacLafferty rearrangement affords the product ions at m/z 416 and 400, containing the two piperazine rings belonging to the epipolythiodioxopipreazines. In addition, the pentacyclic rearrangement involving the loss of the SMe(.) radical seems to occur in the presence of the unfused ring. Finally the product ions at m/z 635 and 591 seem to be the characteristic ions for chaetocochin A.


Asunto(s)
Chaetomium/química , Piperazinas/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en Tándem/métodos , Modelos Estructurales , Estructura Molecular , Extractos Vegetales/química , Espectrometría de Masa por Ionización de Electrospray/instrumentación , Espectrometría de Masas en Tándem/instrumentación
18.
Methods Inf Med ; 46(2): 126-9, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17347741

RESUMEN

OBJECTIVE: A novel method is presented for the investigation of protein properties of sequences using Ramanujan Fourier Transform (RFT). METHODS: The new methodology involves the preprocessing of protein sequence data by numerically encoding it and then applying the RFT. The RFT is based on projecting the obtained numerical series on a set of basis functions constituted by Ramanujan sums (RS). In RS components, periodicities of finite integer length, rather than frequency, (as in classical harmonic analysis) are considered. RESULTS: The potential of the new approach is documented by a few examples in the analysis of hydrophobic profiles of proteins in two classes including abundance of alpha-helices (group A) or beta-strands (group B). Different patterns are provided as evidence. CONCLUSIONS: RFT can be used to characterize the structural properties of proteins and integrate complementary information provided by other signal processing transforms.


Asunto(s)
Aminoácidos , Análisis de Fourier , Estructura Secundaria de Proteína , Análisis de Secuencia de Proteína , Procesamiento de Señales Asistido por Computador , Bases de Datos Factuales , Humanos , Modelos Estructurales , Modelos Teóricos
19.
Curr Opin Biotechnol ; 17(6): 643-52, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17084612

RESUMEN

Fragment-based lead discovery constructs drug leads from small molecular fragments. In theory, this is a highly efficient method for drug discovery, and the technique has become enormously popular in the past few years. In this review, I describe how a variety of approaches in fragment-based lead discovery--including NMR, X-ray crystallography, mass spectrometry, functional screening, and in silico screening--have produced drug leads. Although the examples show that the technique can reliably generate potent molecules, there is still much work to be done to maintain the efficiency of molecules' binding affinities as fragments are linked, expanded, and otherwise improved.


Asunto(s)
Proteínas Portadoras/química , Diseño de Fármacos , Evaluación Preclínica de Medicamentos/métodos , Proteínas/química , Proteínas/uso terapéutico , Relación Estructura-Actividad , Sitios de Unión/efectos de los fármacos , Sitios de Unión/fisiología , Biología Computacional/métodos , Espectroscopía de Resonancia Magnética/métodos , Espectrometría de Masas/métodos , Modelos Químicos , Modelos Estructurales
20.
Water Sci Technol ; 53(12): 199-206, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16889256

RESUMEN

In this work, an organic and nutrient removal pilot plant was used to study the temperature influence on phosphorus accumulating organisms. Three experiments were carried out at 13, 20 and 24.5 degrees C, achieving a high phosphorus removal percentage in all cases. The ASM2d model was calibrated at 13 and 20 degrees C and the Arrhenius equation constant was obtained for phosphorus removal processes showing that the temperature influences on the biological phosphorus removal subprocesses in a different degree. The 24.5 degrees C experiment was simulated using the model parameters obtained by means of the Arrhenius equation. The simulation results for the three experiments showed good correspondence with the experimental data, demonstrating that the model and the calibrated parameters were able to predict the pilot plant behaviour.


Asunto(s)
Modelos Estructurales , Fósforo/análisis , Aguas del Alcantarillado/análisis , Purificación del Agua , Calibración , Proyectos Piloto , Temperatura , Purificación del Agua/instrumentación , Purificación del Agua/métodos , Purificación del Agua/normas
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