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1.
PLoS Pathog ; 4(12): e1000238, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19079578

RESUMEN

Since prion infectivity had never been reported in milk, dairy products originating from transmissible spongiform encephalopathy (TSE)-affected ruminant flocks currently enter unrestricted into the animal and human food chain. However, a recently published study brought the first evidence of the presence of prions in mammary secretions from scrapie-affected ewes. Here we report the detection of consistent levels of infectivity in colostrum and milk from sheep incubating natural scrapie, several months prior to clinical onset. Additionally, abnormal PrP was detected, by immunohistochemistry and PET blot, in lacteal ducts and mammary acini. This PrP(Sc) accumulation was detected only in ewes harbouring mammary ectopic lymphoid follicles that developed consequent to Maedi lentivirus infection. However, bioassay revealed that prion infectivity was present in milk and colostrum, not only from ewes with such lympho-proliferative chronic mastitis, but also from those displaying lesion-free mammary glands. In milk and colostrum, infectivity could be recovered in the cellular, cream, and casein-whey fractions. In our samples, using a Tg 338 mouse model, the highest per ml infectious titre measured was found to be equivalent to that contained in 6 microg of a posterior brain stem from a terminally scrapie-affected ewe. These findings indicate that both colostrum and milk from small ruminants incubating TSE could contribute to the animal TSE transmission process, either directly or through the presence of milk-derived material in animal feedstuffs. It also raises some concern with regard to the risk to humans of TSE exposure associated with milk products from ovine and other TSE-susceptible dairy species.


Asunto(s)
Calostro/química , Leche/química , Proteínas PrPSc/análisis , Scrapie/metabolismo , Scrapie/transmisión , Animales , Química Encefálica , Femenino , Humanos , Glándulas Mamarias Animales/química , Ratones , Ratones Transgénicos , Proteínas PrPSc/patogenicidad , Embarazo , Oveja Doméstica , Distribución Tisular
2.
Clin Nutr ; 25(5): 859-68, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16740345

RESUMEN

BACKGROUND & AIMS: This study was carried out to assess the dose-dependent bone-sparing effect of oleuropein, an olive oil phenolic compound with anti-inflammatory and anti-oxidative properties, on bone loss induced by talc granulomatosis in oestrogen-deficient rat. METHODS: Among 98 rats, 20 were sham-operated (SH) while the others (78) were ovariectomised (OVX). The SH and 26 OVX rats (controls) were given a standard diet for 100 days. The 52 remaining OVX rats were allocated to 4 groups that received oleuropein at 2.5, 5, 10 or 15 mg/kg body weight per day for 100 days. Three weeks before necropsy, an inflammation was induced by subcutaneous injections of talc in half of the SH and OVX rats and in all oleuropein-treated animals. RESULTS: Castration was associated with a decreased bone mineral density (BMD). In OVX rats, inflammation, characterised by an increase of the spleen weight and plasma fibrinogen levels, exacerbated this bone loss, as shown by values of BMD of the total femur metaphyseal and diaphyseal subregions. The 4 doses of oleuropein reduced bone loss and improved inflammatory biomarkers excepted for 5mg/kg BW. CONCLUSIONS: Every dose of oleuropein elicited protective effects on bone mass in this model of ovariectomy associated with inflammation, probably by modulating inflammatory parameters.


Asunto(s)
Conservadores de la Densidad Ósea/farmacología , Osteoporosis/tratamiento farmacológico , Ovariectomía , Piranos/farmacología , Animales , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Biomarcadores/sangre , Densidad Ósea/fisiología , Conservadores de la Densidad Ósea/uso terapéutico , Relación Dosis-Respuesta a Droga , Femenino , Fibrinógeno/metabolismo , Inflamación/complicaciones , Glucósidos Iridoides , Iridoides , Aceite de Oliva , Tamaño de los Órganos , Ovariectomía/efectos adversos , Aceites de Plantas , Piranos/uso terapéutico , Distribución Aleatoria , Ratas , Ratas Wistar , Bazo/patología
3.
J Nutr ; 135(12): 2786-92, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16317121

RESUMEN

Dietary phytoestrogens, such as isoflavones, are used as food additives to prevent menopause-related disorders. In addition to other factors, their bioavailability strongly depends on the activity of intestinal bacteria but the underlying interactions remain poorly understood. A randomized, double-blind, placebo-controlled study was undertaken with 39 postmenopausal women to characterize changes in the dominant microbial communities of the intestinal tract after 2 mo of isoflavone supplementation with and without pro- or prebiotic. The diversity and composition of the dominant microbiota were analyzed by temporal temperature-gradient gel electrophoresis (TTGE) and fluorescent in situ hybridization. Isoflavones alone stimulated dominant microorganisms of the Clostridium coccoides-Eubacterium rectale cluster, Lactobacillus-Enterococcus group, Faecalibacterium prausnitzii subgroup, and Bifidobacterium genus. The stimulation of the Clostridium coccoides-Eubacterium rectale cluster depended on the women's equol excretion and was transient, with the exception of a prolonged bifidogenic effect. Lasting changes in the diversity of the dominant species were also observed. The probiotic strain supplied could be detected by TTGE during its passage through the intestinal tract, and ingestion of fructooligosaccharides triggered a marked and specific bifidogenic effect. In conclusion, this is the first human study that shows changes in the diversity and composition of dominant bacterial communities in response to dietary supplementation with hormone-related compounds combined with functional foods.


Asunto(s)
Bacterias/efectos de los fármacos , Alimentos , Mucosa Intestinal/microbiología , Isoflavonas/farmacología , Posmenopausia , Anciano , ADN Ribosómico/genética , Suplementos Dietéticos , Método Doble Ciego , Heces/química , Amplificación de Genes , Humanos , Isoflavonas/administración & dosificación , Persona de Mediana Edad , Placebos , Probióticos
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