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  Fertilized ova of razorback sucker, Xyrauchen texanus, were adhesive for 3 to 4 hours after fertilization. Cleavage was completed at 24 hours, gastrulation occurred at 34 hours, and blood circulation was established at 117 hours. Hatching occurred from 5.2 to 5.5 days after fertilization. Larvae were from 6.8 to 7.3 mm TL at hatching. Yolk was assimilated at 13 days (10 mm TL). All fins were formed and had ossified rays at 64 days (27 mm TL). The unique nuchal keel appeared about 200 days after fertilization.  相似文献   
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Levamisole added to cultured calvarial bones inhibited spontaneous bone resorption, as indicated by reduced release of calcium and inorganic phosphate to the medium. In addition, levamisole reduced lactate production and release of lysosomal enzymes.  相似文献   
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Summary Levamisole added to cultured calvarial bones inhibited spontaneous bone resorption, as indicated by reduced release of calcium and inorganic phosphate to the medium. In addition, levamisole reduced lactate production and release of lysosomal enzymes.  相似文献   
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The prevalence of dementia in the Western world in people over the age of 60 has been estimated to be greater than 5%, about two-thirds of which are due to Alzheimer's disease. The age-specific prevalence of Alzheimer's disease nearly doubles every 5 years after age 65, leading to a prevalence of greater than 25% in those over the age of 90 (ref. 3). Here, to search for low-frequency variants in the amyloid-β precursor protein (APP) gene with a significant effect on the risk of Alzheimer's disease, we studied coding variants in APP in a set of whole-genome sequence data from 1,795 Icelanders. We found a coding mutation (A673T) in the APP gene that protects against Alzheimer's disease and cognitive decline in the elderly without Alzheimer's disease. This substitution is adjacent to the aspartyl protease β-site in APP, and results in an approximately 40% reduction in the formation of amyloidogenic peptides in vitro. The strong protective effect of the A673T substitution against Alzheimer's disease provides proof of principle for the hypothesis that reducing the β-cleavage of APP may protect against the disease. Furthermore, as the A673T allele also protects against cognitive decline in the elderly without Alzheimer's disease, the two may be mediated through the same or similar mechanisms.  相似文献   
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Summary Spontaneous bone resorption is reduced in cultured calvarial bones from mice with the Chediak-Higashi syndrome, as indicated by decreased mobilization of calcium from the bones to the medium. Although bone resorption in calvaria from mice with this disease can be stimulated by PGE2 and 1 (OH)D3, the amounts of mineral released after stimulation is also decreased.This investigation was supported by grants from the Swedish Association against Rheumatic Diseases, from the Royal 80 Year Fund of King Gustav V, and from the Swedish Medical Research Council (project No 14X-05426).  相似文献   
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Chemical characteristics of Leptotrichia buccalis endotoxin   总被引:2,自引:0,他引:2  
R L Gustafson  A V Kroeger  E M Vaichulis 《Nature》1966,212(5059):301-302
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Zusammenfassung Eier des SeeigelsParacentrotus lividus wurden in unbefruchtetem Zustand und in verschiedenen Entwicklungsstadien gefroren, vakuumgetrocknet, fein zerrieben und mit 0,9%iger Kochsalzlösung extrahiert. Diese Produkte wurden als Suspensionen Kaninchen injiziert und damit Immunsera erhalten, in denen spezifische Antikörper mit Hilfe der Präcipitinreaktion nachzuweisen waren. Als Antigenlösungen dienten klare, dialysierte Zentrifugate der Extrakte.Mit spezifischer Adsorption konnte folgendes festgestellt werden: In den Extrakten von 48 Stunden alten Larven (Plutei) ist eine Antigenfraktion vorhanden, die in früheren Stadien noch fehlt. Sie wird offenbar von der Seeigelzelle erst nach vollendetem Blastulastadium und nach begonnener Gastrulation in größerer Menge gebildet. Extrakte von 48 Stunden alten Larven, die durch Lithiumbehandlung stark vegetativiert waren, unterschieden sich in ihrer serologischen Konstitution anscheinend nicht von denen normaler Plutei.  相似文献   
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