RESUMEN
The consumption of seaweeds has increased in recent years. However, their adverse and beneficial effects have scarcely been studied. Two extracts from the brown seaweed Fucus vesiculosus containing 28.8% polyphenols or 18% polyphenols plus 0.0012% fucoxanthin have been obtained and studied to determine their toxicity in mice and rats and also their antioxidant activity. Both extracts were shown to lack any relevant toxic effects in an acute toxicity test following a 4 week daily treatment in rats. The extracts exhibited antioxidant activity in noncellular systems and in activated RAW 264.7 macrophages, as well as in ex vivo assays in plasma and erythrocytes, after the 4 week treatment in rats. Our ex vivo results indicated that compounds from extract 2 may be more easily absorbed and that the antioxidants in their parent or metabolized form are more active. These findings support the view that the daily consumption of F. vesiculosus extract 2 (Healsea) would have potential benefits to humans.
Asunto(s)
Antioxidantes/farmacología , Fucus/química , Extractos Vegetales/farmacología , Extractos Vegetales/toxicidad , Animales , Línea Celular , Eritrocitos/efectos de los fármacos , Femenino , Flavonoides/análisis , Activación de Macrófagos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Masculino , Ratones , Fenoles/análisis , Extractos Vegetales/química , Polifenoles , Ratas , Ratas Sprague-DawleyRESUMEN
The significance of ultrastructural changes in the gill epithelial cells as a parameter of detection of Hg exposure in the flat oyster, Ostrea edulis, was tested by a 34-day exposure to 5 microg l(-1) of Hg. The concentration of Hg (38.76 microg g(-1) dry weight) in gill tissue was maximal after 25 days and then decreased. The histological pattern of gill filaments in control samples did not vary throughout the experiment, except for the volume of mucocytes after 4 days of exposure, as an adaptation to experimental conditions. This volume increased significantly and then decreased according to the accumulation of Hg in the gills. After 18 days, absorptive and ciliated cells of the gill epithelium showed blebs in microvilli membranes, discocilia and swollen mitochondrial cristae. Both cell types showed distinct cellular lysis stages after 25 days of exposure. These are the target cells of Hg and other metals and the reported hypertrophy of mucocytes increase occurs in response to pollution by Hg, which could contribute to the detoxification process.
Asunto(s)
Branquias/efectos de los fármacos , Cloruro de Mercurio/toxicidad , Ostreidae/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Animales , Monitoreo del Ambiente/métodos , Células Epiteliales/efectos de los fármacos , Células Epiteliales/ultraestructura , Branquias/patología , Cloruro de Mercurio/farmacocinética , Microscopía Electrónica , Dilatación Mitocondrial/efectos de los fármacos , Membrana Mucosa/efectos de los fármacos , Membrana Mucosa/patología , Contaminantes Químicos del Agua/farmacocinéticaRESUMEN
BACKGROUND: Pathologic changes of the pancreas have been observed as early as the recognition of the disease termed initially "cystic fibrosis of the pancreas". Atrophy of the gland and its fatty infiltration were considered as usual features. The aim of this study was to follow-up the evolution of cystic fibrosis pancreas and to define its successive stages in correlation with the clinical, biochemical, and imaging findings. METHODS: Fifty-five patients were followed up during 9 years. The patients' genetic backgrounds were systematically performed. Blood lipase levels were analyzed systematically at each consultation of the patients and in the event of bouts of abdominal pains. Imaging using mainly echograms and tomodensitometric scans were regularly performed: echograms every 6 months, and tomodensitometric scans every 1 to 2 years. Magnetic resonance imaging was performed in four patients. RESULTS: Five groups of patients were identified on the basis of tomodensitometric scan findings: normal pancreas (n = 4), incomplete lipomatosis of the pancreas (n = 9), complete lipomatosis of the pancreas (n = 23), cystic pancreas (n = 5), macrocystic pancreas (n = 1), atrophic pancreas (n = 13). Pancreas exocrine function was not correlated with findings. Forty episodes of pancreatitis were observed in seven patients. They had bouts of abdominal pain and elevation of lipase levels. Five of these patients were composite heterozygotes (D508/other). Incomplete lipomatosis represents an intermediate stage leading toward complete lipomatosis or toward atrophy after pancreatitis. CONCLUSIONS: Studies of pancreatic function should be performed routinely in cystic fibrosis, especially in pancreatic sufficiency or in patients with normal pancreas images. Acute pancreatitis should be diagnosed and properly identified to be differentiated from other acute abdominal syndromes occurring in cystic fibrosis.
Asunto(s)
Fibrosis Quística/patología , Diagnóstico por Imagen , Páncreas/patología , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lipasa/sangre , Lipomatosis/patología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Quiste Pancreático/patología , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , UltrasonografíaRESUMEN
This study examines the direct and indirect effects of atrazine on two grazer species--Physa acuta and Ancylus fluviatilis--as assessed by changes in mortality rates, biomass, searching behaviour and histological properties. No direct effects were observed in the acute toxicity test (48 h) with 0.02, 0.2, 2, 10 and 20 mg l(-1) of atrazine. A chronic toxicity test (18 days) performed in six experimental channels with 15 microg l(-1) of atrazine showed significant changes in grazer behaviour, increased searching velocity and different movement patterns in animals exposed to herbicide. No significant effects were observed in rates of mortality and biomass. Kidney cells of Physa acuta displayed an important cell lysis when animals were exposed to 0.1 mg l(-1) of atrazine for 10 days, and this effect was not reversed after a decontamination process. These results provide evidence of behavioural and structural changes in freshwater molluscs due to a subacute atrazine concentration.
Asunto(s)
Atrazina/toxicidad , Conducta Animal/efectos de los fármacos , Herbicidas/toxicidad , Caracoles/efectos de los fármacos , Animales , Clorofila/metabolismo , Clorofila A , Conducta Alimentaria/efectos de los fármacos , Agua Dulce , Riñón/efectos de los fármacos , Riñón/patología , Trastornos del Movimiento/etiología , Pruebas de ToxicidadRESUMEN
Oysters display a diversity of uptake mechanisms for metallic elements and distribution in the target organs, namely gills and the digestive gland. Various tissues of the flat oyster, Ostrea edulis, were studied following experimental exposure to 0.025 microM (5 micrograms l-1) of mercury, for up to 34 days. All animals survived the treatment. Data indicate Hg accumulation in gill tissue with a maximum concentration of 38.76 micrograms g-1 dry weight after 25 days of exposure. Hg levels were lower in remaining tissues, in which the maximum concentration (18.47 micrograms g-1 dry weight) was reached after 18 days of exposure. After these times, concentration in both tissues decreased. Results show that oysters can accumulate Hg from the environment, without their survival being affected during the experimental period. Structural alteration of epithelial tissues of gill and digestive gland of flat oyster was comparable with effects described for other metallic elements in bivalve molluscs. Interstitial tissue was disorganized in the digestive gland, and ultrastructural changes in intracellular endomembranes were detected in epithelial cells of the digestive gland after 18 days of treatment. After 25 days, absorptive epithelial cells of gills showed highly dilated, swollen microvilli. These intracellular alterations are parameters of the incipient response to the accumulation of mercury.
Asunto(s)
Mercurio/metabolismo , Ostreidae/metabolismo , Animales , Sistema Digestivo/efectos de los fármacos , Sistema Digestivo/ultraestructura , Células Epiteliales/efectos de los fármacos , Células Epiteliales/ultraestructura , Branquias/efectos de los fármacos , Branquias/ultraestructura , Mercurio/análisis , Mercurio/toxicidad , Microscopía Electrónica , Ostreidae/efectos de los fármacos , Reproducibilidad de los Resultados , Espectrofotometría AtómicaRESUMEN
Experience gained from liver studies in 450 patients with cystic fibrosis, seen in a 38 year period from 1964 to 1992, is surveyed. Of these, 31 (7%) showed findings that indicated multilobular cirrhosis. There was a slight but not significant male predominance: 19 males against 12 females. Liver disease had its onset during childhood in most cases. The natural course of liver disease and of cirrhosis is protracted. All patients were routinely evaluated by way of: (i) clinical examination, (ii) biochemical studies and specifically estimation of transaminases and gamma glutamyltransferase, and (iii) liver imaging, ultrasonography, and computed tomography. The study aimed to detect early liver disease, that is multilobular cirrhosis and its complications, with a view to optimal introduction of treatment with ursodeoxycholic acid as this drug shows promise for preventing or stabilising the cirrhotic process. Effects of surgical treatment on portal hypertension are surveyed. These include portacaval shunting, partial splenectomy (considered the procedure of choice), liver transplant in the event of liver failure, or a triple transplant (liver, lungs, and heart) if necessary. One triple transplant was successfully performed in a boy of 10 years with a 2 year follow up.
Asunto(s)
Fibrosis Quística/complicaciones , Hipertensión Portal/cirugía , Cirrosis Hepática/terapia , Ácido Ursodesoxicólico/uso terapéutico , Adolescente , Adulto , Causas de Muerte , Niño , Femenino , Estudios de Seguimiento , Trasplante de Corazón-Pulmón/mortalidad , Humanos , Hipertensión Portal/etiología , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/mortalidad , Trasplante de Hígado/mortalidad , Masculino , Derivación Portocava Quirúrgica , Esplenectomía , Factores de Tiempo , Resultado del TratamientoRESUMEN
We describe sperm ultrastructure and acrosome differentiation during spermiogenesis in Crassostrea gigas (Mollusca Bivalvia). The sperm cell is a uniflagellated cell of the primitive type. The head region contains a rounded or conical nucleus surmounted by small acrosome. This organelle consists of a membrane-bound acrosomal granule, the contents of which have a homogeneous density, except in the anterior region, which is positive for PTA. The acrosome also surrounds the perforatorium, which includes oriented fibrillar elements: this is the axial body. The middle piece contains four mitochondria encircling two perpendicular centrioles. The distal centriole is provided with a system of mechanical fixation to the plasma membrane, consisting of nine fibers in radial arrangement. The tail flagellum, about 50 microns long, contains the usual microtubular axoneme.