Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Clin Radiol ; 79(3): 230-236, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38092646

RESUMEN

AIM: To assess the accuracy of Magnetic Resonance Index of Activity (MaRIA) in evaluating therapeutic efficacy in Crohn's disease (CD) patients with different activity levels using ileocolonoscopy as the reference standard. MATERIALS AND METHODS: Forty-eight patients underwent magnetic resonance enterography (MRE) and ileocolonoscopy at baseline, week 26, and week 52, along with the Simple Endoscopic Score for Crohn's Disease (SES-CD) and MaRIA scores. According to the SES-CD score at baseline, all patients were subdivided into mild, moderate, and severe activity subgroups. The identification of endoscopic mucosal healing (MH) was explored primarily. Moreover, the Crohn's Disease Activity Index (CDAI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), and interleukin-6 (IL-6) levels were collected and analysed. RESULTS: MaRIA correlated significantly with SES-CD and CRP at baseline, week 26, and week 52. The discrepancies in MaRIA and SES-CD were statistically significant before and after treatment. MaRIA = 24.43 and ΔMaRIA = 12.77 as the cut-off points were found to have high diagnostic accuracy for predicting MH. MaRIA (p<0.001), SES-CD (p<0.001), CRP (p<0.05), ESR (p<0.05), and CDAI score (p<0.05) in patients with MH were considerably decreased compared to those in patients without MH. CONCLUSIONS: MRE has good application value in evaluating the therapeutic response of CD patients treated with biological agents. MaRIA is a reliable indicator in the follow-up of CD patients, which is strongly correlated with SES-CD, and it has high accuracy in predicting endoscopic MH.


Asunto(s)
Enfermedad de Crohn , Humanos , Enfermedad de Crohn/diagnóstico por imagen , Enfermedad de Crohn/tratamiento farmacológico , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Índice de Severidad de la Enfermedad
2.
Sci Total Environ ; 610-611: 121-136, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-28803190

RESUMEN

A large and complex suite of 295 legacy and new halogenated persistent organic pollutants (POPs) were investigated in fat or liver tissue samples of polar bears collected in 2013-2014 from Southern (SHB) and Western (WHB) subpopulations of the Canadian Arctic contaminants hotspot of Hudson Bay. A total of 210 POPs were detected and/or quantifiable with some frequency in all fat or liver samples. POP profile and concentration differences were investigated both within (e.g. age and sex) and between the two subpopulations. Two time-point comparisons were made relative to POPs reported for Hudson Bay polar bears harvested in 2007-2008. ΣPolychlorinated biphenyl (PCB) concentrations at both time points were the most concentrated of the POP groups, and were spatially uniform with no detectable influence of sex or age, as were concentrations of the dominant congener CB153. ΣChlordanes (ΣCHLs, 74-79% oxychlordane) and the Σperfluoroalkyl substances (ΣPFASs, ≈60% perfluorooctane sulfonate (PFOS)) had the second greatest POP group concentrations in SHB and WHB respectively, with ΣPFASs and ΣCHLs being significantly influenced by age and/or sex. ΣCHLs were spatially uniform but ΣPFASs were greater in the SHB bears, as were e.g. some flame retardants, due to e.g. local contamination and/or changes in bear behavior and diet. Endosulfans and hexabromocyclododecane were detectable in samples from 2007-2008 but not from 2013-2014, which is consistent with their global POP regulations. ΣPolychlorinated naphthalenes (ΣPCNs) were consistently detected at relatively high concentrations compared to other arctic wildlife, however these concentrations were low relative to legacy POPs. ΣShort-chain chlorinated paraffins (ΣSCCPs) were major contributors to the overall POPs burden with concentrations comparable to other legacy POPs, though there was no significant difference between or within subpopulations for PCNs or SCCPs. Except for octachlorostyrene, POPs concentrations were generally lower in female and male bears from SHB in 2013-2014 relative to 2007-2008, however those of WHB males were greater over the same timeframe for almost all POPs.


Asunto(s)
Tejido Adiposo/química , Contaminantes Ambientales/análisis , Hígado/química , Ursidae , Animales , Regiones Árticas , Bahías , Canadá , Clordano/análisis , Monitoreo del Ambiente , Femenino , Masculino , Bifenilos Policlorados/análisis
3.
Chemosphere ; 58(10): 1355-63, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15686753

RESUMEN

Surface soils from the outskirts of Beijing were analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs) using gas chromatography and mass spectrometry (GC-MS). The distribution map of total PAHs content was obtained as a contour plot. The concentration range of 16 PAHs varied by over two orders of magnitude from 0.016 microg g-1 in rural to 3.884 microg g-1 in suburban soils with the relatively standard deviation of 70.5%, showing large differences in the extent of PAHs pollution at the various sampling sites. It was notable that the concentration of BaP was 0.005-0.270 microg g-1 with a mean of 0.055 microg g-1. In general, the distribution of PAHs centered on the high molecular weight PAHs known to be carcinogenic. The 4-6 ring PAHs represented about 66% in rural samples and 70% in suburban soils of the total PAHs found. There was relatively good relationship among most of the individual PAHs and the compounds of Pyr, BaA, Flu, BbF, BaP, Chr and Ph gave strong correlation (r>0.8) with the sum of PAHs. The selected marked compounds, a principal component analysis (PCA) and special PAHs compound ratios (Ph/An vs Flu/Pyr; summation operator COMB/ summation operator EPA-PAHs) suggest the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in Beijing outskirts soils.


Asunto(s)
Ciudades , Monitoreo del Ambiente/estadística & datos numéricos , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/análisis , Suelo/análisis , China , Cromatografía de Gases y Espectrometría de Masas
4.
J Anal Toxicol ; 29(4): 209-16, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15975248

RESUMEN

Hydroxylated metabolites of polychlorinated biphenyls (HO-PCBs) and pentachlorophenol (PCP) are halogenated phenolic compounds, and they are increasingly common as environmental contaminants mainly in the blood of wildlife and humans. A methodology based on high-performance liquid chromatography (reversed-phase)-electrospray (negative) ionization-tandem quadrupole mass spectrometry (LC-ESI(-)-MS-MS) in the select ion monitoring or multiple reaction monitoring modes was developed for HO-PCB and PCP determination in blood plasma and serum. Among 11 environmentally relevant HO-PCB congeners and PCP spiked to fetal calf serum, quantitative assessments, including matrix effects on ESI(-) suppression/ enhancement, showed process (recovery) efficiencies of 73% to 89% without internal standard (IS) correction, and 88% to 103% with IS correction, and method limits of quantification ranging from 1 to 50 pg/g (wet weight). Using the developed LC-ESI(-)-MS methodology in comparison with GC-MS and GC-ECD based approaches, similar results were found for HO-PCB identification and quantification in the plasma of polar bear (Ursus maritimus) from the Canadian arctic. LC-ESI(-)-MS identified four HO-PCB congeners [4'-HO-2,2',4,6,6'-pentachlorobiphenyl (4'-HO-CB104), 4-HO-2,3,3',4',5-pentachlorobiphenyl (4-HO-CB107), 4-HO-2,3,3',5,5',6-hexachlorobiphenyl (4-HO-CB165) and 3'-HO-2,2',3,4,4',5,5'-heptachlorobiphenyl (3'-HO-CB180)], and 14 additional tetra- to hepta-chlorinated HO-PCBs isomers in the polar bear plasma.


Asunto(s)
Contaminantes Ambientales/sangre , Bifenilos Policlorados/sangre , Ursidae/sangre , Animales , Canadá , Bovinos , Cromatografía Líquida de Alta Presión , Monitoreo del Ambiente , Contaminantes Ambientales/metabolismo , Hidroxilación , Pentaclorofenol/sangre , Bifenilos Policlorados/metabolismo , Estándares de Referencia , Espectrometría de Masa por Ionización de Electrospray
5.
Chemosphere ; 39(10): 1639-50, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10520484

RESUMEN

The photodegradations of eight individual PCB congeners (5, 31, 52, 77, 87, 126, 138, 169) in hexane have been investigated employing a mercury lamp. All degradation reactions of the above mentioned PCB congeners are of the pseudo first order. The principal products of PCB decomposition are the less chlorinated biphenyls, and no PCB-solvent adducts are found. Symmetrical and coplanar PCB congeners show lower photoreactivities. The reactivities of the chlorine atoms at various positions of PCB rings are generally in the order: ortho > meta > para. Photodechlorinations occur mainly on the more substituted rings, when the numbers of chlorine atoms on the two phenyl rings are unequal. During photodegradation, some coplanar PCB congeners are formed, which make the TEQ of solutions to decrease slowly or even to increase.


Asunto(s)
Hexanos/química , Bifenilos Policlorados/química , Bifenilos Policlorados/efectos de la radiación , Cromatografía de Gases , Cromatografía de Gases y Espectrometría de Masas , Semivida , Indicadores y Reactivos , Isomerismo , Cinética , Fotólisis , Rayos Ultravioleta
6.
Chemosphere ; 57(1): 61-6, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15356925

RESUMEN

During one to three consecutive periods of 2 weeks, broiler chickens (n = 108) received test dies to which different amount of PCBs (7 congeners) were added. The relationship between exposure time and accumulation of individual congeners in different chicken tissues, such as breast, thigh and abdominal fat tissue, was observed. In all tissues, the vast majority of the PCB accumulation occurred during the first 2 weeks of exposures. After that, PCB concentrations only increased in the abdominal fat tissue of the animals. The individual PCBs were distributed differently in the various tissues. While CBs 28, 118, 138, 153 and 180 accumulated in the chickens, CBs 52 and 101 were metabolized, but no methyl sulphone metabolites of these congeners could be detected. Our results provide information on the absorption, tissue distribution and biotransformation of the individual PCB congeners and confirm the structure-activity relationships for metabolism of PCBs in birds, which are different from those in fish or mammalian species.


Asunto(s)
Pollos/metabolismo , Bifenilos Policlorados/farmacocinética , Absorción , Análisis de Varianza , Alimentación Animal/análisis , Animales , Biotransformación/fisiología , Cromatografía de Gases , Contaminación de Alimentos/análisis , Bifenilos Policlorados/metabolismo , Factores de Tiempo , Distribución Tisular
7.
J Thromb Haemost ; 8(1): 148-56, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19691485

RESUMEN

AIM: To determine whether an association exists between mean platelet volume (MPV) and acute myocardial infarction (AMI) and other cardiovascular events. Platelet activity is a major culprit in atherothrombotic events. MPV, which is widely available in clinical practice, is a potentially useful biomarker of platelet activity in the setting of cardiovascular disease. METHODS AND RESULTS: We performed a systematic review and meta-analysis investigating the association between MPV and AMI, all-cause mortality following myocardial infarction, and restenosis following coronary angioplasty. Results were pooled using random-effects modeling. Pooled results from 16 cross-sectional studies involving 2809 patients investigating the association of MPV and AMI indicated that MPV was significantly higher in those with AMI than those without AMI [mean difference 0.92 fL, 95% confidence interval (CI) 0.67-1.16, P < 0.001). In subgroup analyses, significant differences in MPV existed between subjects with AMI, subjects with stable coronary disease (P < 0.001), and stable controls (P < 0.001), but not vs. those with unstable angina (P = 0.24). Pooled results from three cohort studies involving 3184 patients evaluating the risk of death following AMI demonstrated that an elevated MPV increased the odds of death as compared with a normal MPV (11.5% vs. 7.1%, odds ratio 1.65, 95% CI 1.12-2.52, P = 0.012). Pooled results from five cohort studies involving 430 patients who underwent coronary angioplasty revealed that MPV was significantly higher in patients who developed restenosis than in those who did not develop restenosis (mean difference 0.98 fL, 95% CI 0.74-1.21, P < 0.001). CONCLUSIONS: Elevated MPV is associated with AMI, mortality following myocardial infarction, and restenosis following coronary angioplasty. These data suggest that MPV is a potentially useful prognostic biomarker in patients with cardiovascular disease. Whether the relationship is causal, and whether MPV should influence practice or guide therapy, remains unknown.


Asunto(s)
Angioplastia Coronaria con Balón/efectos adversos , Plaquetas/patología , Enfermedad de la Arteria Coronaria/terapia , Reestenosis Coronaria/etiología , Infarto del Miocardio/etiología , Pruebas de Función Plaquetaria , Anciano , Angioplastia Coronaria con Balón/mortalidad , Tamaño de la Célula , Enfermedad de la Arteria Coronaria/sangre , Enfermedad de la Arteria Coronaria/mortalidad , Reestenosis Coronaria/sangre , Reestenosis Coronaria/mortalidad , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Infarto del Miocardio/sangre , Infarto del Miocardio/mortalidad , Oportunidad Relativa , Recuento de Plaquetas , Valor Predictivo de las Pruebas , Pronóstico , Medición de Riesgo , Factores de Riesgo
8.
Environ Sci Technol ; 41(21): 7252-9, 2007 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-18044496

RESUMEN

We examined the concentrations and spatial patterns of congeners of PBDEs, PCBs, and organochlorine pesticides in snapping turtle (Chelydra serpentina) eggs from Areas of Concern (AOCs) on the Canadian shores of Lake Ontario, St. Lawrence River, and connecting channels. Eggs from Lyons Creek (Niagara River AOC) reflected a local PCB source over a range of 7.5 km (3.2-10.8) from the Welland Canal. PCB contamination in eggs declined with increasing distance from the Welland Canal, whereas the relative contribution of congeners associated with Aroclor 1248/1254 increased with sigma PCB concentrations. Compared to turtle eggs from other sites in Lake Erie and Lake Ontario, eggs from Lyons Creek and Snye Marsh had PCB congener patterns that reflected a strong contribution from Aroclor 1254. PCBs in the eggs were associated with industrial sources and reflected the composition of different Aroclor technical mixtures. Organochlorine pesticides in eggs tended to be highest at Hamilton Harbour and Bay of Quinte AOCs, and were dominated by DDE, sigma chlordane, and mirex. In contrast, PBDE congener patterns in turtle eggs resembled PentaBDE technical formulations regardless of absolute concentrations or location, and were largely associated with urban environments.


Asunto(s)
Hidrocarburos Clorados/análisis , Plaguicidas/análisis , Éteres Fenílicos/análisis , Bifenilos Polibrominados/análisis , Tortugas , Contaminantes Químicos del Agua/análisis , Cigoto/química , Animales , Monitoreo del Ambiente , Ontario
9.
J Environ Monit ; 5(5): 786-90, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14587850

RESUMEN

Selected persistent organic pollutants including HCHs, DDTs and PAHs together with PAEs were determined in the greenhouse soils from Beijing suburbs. The total concentrations were 11.64-29.80 ng g(-1) for HCHs, 18.04-101.33 ng g(-1) for DDTs, 1.34-3.15 microg g(-1) for PAEs and 1.92-7.84 microg g(-1) for PAHs, respectively. Predominance of beta-HCH in all samples was obviously observed, suggesting a lack of new HCHs sources. High concentrations of DDE and DDD in comparison to their parents in the samples indicated that most of the DDT had been transformed into its metabolites. The contamination of PAHs was relatively serious and the most abundant compounds were 4-, 5- and 6-ring unsubstituted PAHs. The profiles reflect the important effect of traffic on the PAHs remaining in greenhouse soils. Three phthalate esters (DIBP, DnBP and DEHP) accounted for more than 97% of the phthalates studied. Analysis of n-alkanes was also performed in order to trace the natural or anthropogenic sources of hydrocarbons. Characterization and identification of these compounds in greenhouse soil may help in development of strategies to be used in monitoring organic pollutants in this region.


Asunto(s)
Agricultura , DDT/análisis , Hexaclorociclohexano/análisis , Insecticidas/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/análisis , China , Monitoreo del Ambiente
10.
Arch Environ Contam Toxicol ; 44(1): 89-96, 2003 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-12434223

RESUMEN

In this study we investigated the accumulation of organochlorine compounds (HCB, 3 HCH-isomers, p,p'-DDT and its metabolites and 18 PCB congeners) in the muscle and fat tissue of nestling great tits (Parus major) from four study sites located in an area with extensive environmental contamination. The concentration of p,p'-DDT, p,p'-DDD, alpha-, beta-, gamma-HCH, and PCB congeners 128 and 149 were below the limit of detection in all muscle and fat samples. In muscle tissue the concentrations of HCB and congeners 28, 52, 101, 110, and 194 were in more than 50% of the cases below detection limit and these data were excluded from statistical analysis. Sigma PCB in muscle tissue ranged from 461 to 1060 ng/g lipid weight and in fat from 776 to 1779 ng/g lipid weight. p,p'-DDE had concentrations ranging from 106 to 205 ng/g lipid weight in muscle and from 201 to 348 ng/g lipid weight in fat. HCB concentrations were very low, ranging from ND to 7.0 ng/g lipid weight in fat. We found significant differences among study sites in the concentration of Sigma PCB and of almost all individual congeners in both muscle and fat tissue. Concentrations of p,p'-DDE in muscle and fat of great tit nestlings tended to differ among sites. Principal Component Analysis (PCA) showed that the study sites with the highest Sigma PCB level had a different PCB profile than the two other sites. Our study illustrates that insectivorous passerines with a limited home range, such as the great tit, are suitable biomonitors for terrestrial organochlorine contamination.


Asunto(s)
Exposición a Riesgos Ambientales , Contaminantes Ambientales/farmacocinética , Insecticidas/farmacocinética , Bifenilos Policlorados/farmacocinética , Pájaros Cantores , Tejido Adiposo/química , Animales , Animales Recién Nacidos , Monitoreo del Ambiente , Contaminantes Ambientales/análisis , Insecticidas/análisis , Músculo Esquelético/química , Bifenilos Policlorados/análisis , Distribución Tisular
11.
Arch Environ Contam Toxicol ; 41(1): 73-82, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11385592

RESUMEN

The declining size of the Baltimore Harbor black-crowned night-heron (Nycticorax nycticorax) colony has been hypothesized to be linked to polychlorinated biphenyl (PCB) exposure. In 1998, a "sample egg" was collected from 65 black-crowned night-heron nests (each containing > or = three eggs) for contaminant analysis, and the remaining eggs in these 65 nests, plus four two-egg nests, were monitored for hatching and fledging success. Eggs were also collected from 12 nests at Holland Island, a reference site in southern Chesapeake Bay. Samples were analyzed for 26 organochlorine pesticides and metabolities and 145 PCB congeners. Pesticide and metabolite concentrations, including p,p'-DDE, were well below thresholds associated with adverse reproductive effects at both sites. Average concentration of total PCBs, 12 Ah receptor-active PCB congeners, and toxic equivalents in eggs from Baltimore Harbor were greater (up to 35-fold) than that observed in Holland Island samples. Overall nest success at the Baltimore Harbor heronry was estimated by the Mayfield method to be 0.74, and the mean number of young fledged/hen was 2.05, which is within published productivity estimates for maintaining a stable black-crowned night-heron population. Using logistic regression, no significant relationships were found between organochlorine contaminant concentrations in sample eggs and hatching, fledging, or overall reproductive success. Processes other than poor reproduction (e.g., low postfledging survival, emigration, habitat degradation) may be responsible for the declining size of the Baltimore Harbor colony.


Asunto(s)
Aves , Hidrocarburos Clorados , Insecticidas/efectos adversos , Reproducción , Animales , Femenino , Insecticidas/análisis , Masculino , Maryland , Dinámica Poblacional , Análisis de Supervivencia
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA