Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
J Acoust Soc Am ; 141(4): 2399, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28464619

RESUMEN

The importance of non-acoustical factors including the type of visual environment on human noise perception becomes increasingly recognized. In order to reveal the relationships between long-term noise annoyance and different types of neighborhood views, 2033 questionnaire responses were collected for studying the effect of perceptions of different combinations of views of sea, urban river, greenery, and/or noise barrier on the annoyance responses from residents living in high-rise apartments in Hong Kong. The collected responses were employed to formulate a multivariate model to predict the probability of invoking a high annoyance response from residents. Results showed that views of sea, urban river, or greenery could lower the probability, while views of noise barrier could increase the probability. Views of greenery had a stronger noise moderation capability than views of sea or urban river. The presence of an interaction effect between views of water and views of noise barrier exerted a negative influence on the noise annoyance moderation capability. The probability due to exposure to an environment containing views of noise barriers and urban rivers would be even higher than that due to exposure to an environment containing views of noise barriers alone.


Asunto(s)
Percepción Auditiva , Automóviles , Exposición a Riesgos Ambientales/efectos adversos , Vivienda , Genio Irritable , Ruido del Transporte/efectos adversos , Percepción Visual , Estimulación Acústica , Adulto , Anciano , Planificación de Ciudades , Monitoreo del Ambiente/métodos , Arquitectura y Construcción de Instituciones de Salud , Femenino , Hong Kong , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa , Encuestas y Cuestionarios , Factores de Tiempo
2.
Histol Histopathol ; 24(9): 1161-9, 2009 09.
Artículo en Inglés | MEDLINE | ID: mdl-19609863

RESUMEN

Animal models used to study the pathogenesis of non-alcoholic fatty liver disease (NAFLD) are, in general, either genetically altered, or fed with a diet that is extremely high in fat or carbohydrates. Recent findings support the role of oxidative stress, lipid peroxidation and inflammation as probable causative factors. We hypothesize that not only the amount of dietary fat, but the quality of fat is also important in inducing NAFLD. Based on previous observations that female rats fed a diet comprising unsaturated fatty acids are susceptible to liver injury, we proposed that female rats fed with a diet containing fish oil and dextrose would develop pathological and biochemical features of NAFLD. We fed a highly unsaturated fat diet (30% fish oil) to female Sprague-Dawley rats (180-200g), consumed ad libitum for 8 weeks (NAFLD; n=6-8 ). Control animals (CF; n=6-8) were fed with an isocaloric regular rat chow. At killing, blood and liver samples were collected for serum alanine aminotransferase (ALT), histology and molecular analysis. Each histological sample was evaluated for fatty liver (graded from 0 to 4+ according to the amount of fatty change), necrosis (number of necrotic foci (no./mm2) and inflammation (cells per mm2). The amount of collagen formation was estimated based on the amount of Sirius Red staining. Reverse transcriptase polymerase chain reaction (RT-PCR) was carried out for tumor necrosis factor alpha (TNF-alpha), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), adiponectin, glutathione peroxidase (GPx), superoxide dismutase (Cu/Zn SOD) and catalase (CAT). Western Blot analysis was done for cyclooxygenases-2 (COX-2), inducible nitric oxide synthase (iNOS) and nitrotyrosine. Electrophoretic mobility shift assay was performed for nuclear factor-kappa B (NF-kB) activity. NAFLD rats had a significantly higher serum ALT level, amount of collagen formation, fatty liver, necrosis and inflammation when compared with the chow-fed control rats. mRNA and protein levels of NF-kB regulated genes, which included TNF-alpha, COX-2 and iNOS were also significantly (p<0.01; p<0.01; p<0.05 respectively) upregulated in the NAFLD group when compared with the chow-fed control rats. mRNA levels of antioxidants CAT and GPX were reduced by 35% and 50% respectively in the NAFLD group. However, Cu/Zn SOD mRNA was similar in both groups. The mRNA level of adiponectin was also reduced in NAFLD group. NF-kB activity was markedly increased in the NAFLD rats (p<0.01). The level of oxidative stress, represented by the formation of nitrotyrosine, was significantly elevated in the NAFLD rats (p<0.01). We conclude that NAFLD rats demonstrated several features of NAFLD, which included fatty liver, inflammation, necrosis, increased oxidative stress, an imbalance between pro and antioxidant enzymes mRNAs, reduced adiponectin levels and upregulation of pro-inflammatory mediators. We propose that female rats fed with a diet containing highly unsaturated fatty acids are an extremely useful model for the study of NAFLD.


Asunto(s)
Grasas de la Dieta/metabolismo , Modelos Animales de Enfermedad , Hígado Graso/patología , Hepatopatías/patología , Adiponectina/metabolismo , Administración Oral , Alanina Transaminasa/sangre , Animales , Estudios de Casos y Controles , Catalasa/metabolismo , Colágeno/biosíntesis , Ciclooxigenasa 2/metabolismo , Grasas de la Dieta/administración & dosificación , Ácidos Grasos Insaturados/administración & dosificación , Femenino , Glutatión Peroxidasa/metabolismo , Inflamación/inducido químicamente , Inflamación/etiología , Inflamación/patología , Hepatopatías/etiología , Necrosis/inducido químicamente , Necrosis/etiología , Necrosis/patología , Óxido Nítrico Sintasa de Tipo II/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Superóxido Dismutasa/metabolismo , Factores de Tiempo , Factor de Necrosis Tumoral alfa/metabolismo
3.
Food Chem Toxicol ; 38(2-3): 173-8, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10717357

RESUMEN

The nutritive composition of a hot aqueous extract of wild Ganoderma fruit bodies was determined. This extract was assessed for cytotoxicity and in vivo genotoxicity by both acute and subchronic exposure of mice (given by mouth at a dose equivalent to extract of 220g fresh Ganoderma fruit body/kg body weight). To test any alleged protection against mutagens by Ganoderma treatments, the mice were injected intraperitoneally with the radiomimetic mutagen ethyl methanesulfonate (EMS), and after 24hr of treatment their lymphocytes were examined using the comet assay. Ganoderma extract consisted of Folin-positive material (68.9% of dry weight), but protein comprised only 7.3% of dry weight. Glucose accounted for 11. 1% and metals 10.2% of dry weight (K, Mg and Ca being the major components with Ge (often touted as being of value in sales literature for Ganoderma preparations) having the fifth highest metal concentration at 489 microg/g). In comparison to rodent chow, Ganoderma extract was a modest dietary supplement. No evidence was found for genotoxic chromosomal breakage nor cytotoxic effects by Ganoderma extract in the mouse, nor did it protect against the effects of ethyl methanesulfonate. We found no support in this study for the extract having any value in protecting against the test mutagen.


Asunto(s)
Daño del ADN , Medicamentos Herbarios Chinos/toxicidad , Reishi/química , Administración Oral , Animales , Quimioprevención , Ensayo Cometa , Relación Dosis-Respuesta a Droga , Medicamentos Herbarios Chinos/farmacología , Metanosulfonato de Etilo/farmacología , Infusiones Parenterales , Masculino , Ratones , Pruebas de Mutagenicidad , Mutágenos/farmacología , Valor Nutritivo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA