873 resultados para Strip of ducts
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The vitamin D endocrine system is regulated reciprocally by renal 25-hydroxyvitamin D3 1 alpha- and 24-hydroxylases. Previously, we reported that renal proximal convoluted tubules, the major site of 1 alpha, 25-dihydroxyvitamin D3 production, have vitamin D receptors. In the presence of vitamin D receptors, renal proximal convoluted tubules cannot maintain the state of enhanced production of 1 alpha, 25-dihydroxyvitamin D3. To clarify this discrepancy, we proposed a working hypothesis for the reciprocal control of renal 25-hydroxyvitamin D3 1 alpha- and 24-hydroxylase activities. In rat models of enhanced renal production of 1 alpha, 25-dihydroxyvitamin D3, expression of vitamin D receptors and 25-hydroxyvitamin D3 24-hydroxylase mRNAs was strikingly suppressed in renal proximal convoluted tubules but not in the cortical collecting ducts. In vitamin D-deficient rats with up-regulated renal 25-hydroxyvitamin D3 1 alpha-hydroxylase activity, expression of vitamin D receptor mRNA in renal proximal convoluted tubules was also down-regulated, indicating that the down-regulation of vitamin D receptor mRNA is not the result of the enhanced production of 1 alpha, 25-dihydroxyvitamin D3. In Japanese quail models with up-regulated renal 25-hydroxyvitamin D3 1 alpha-hydroxylase activity by sex steroids, expression of vitamin D receptor mRNA was also down-regulated in the kidney but not in the duodenum. These results suggest that the down-regulation of vitamin D receptors plays a critical role in production of 1 alpha, 25-dihydroxyvitamin D3 in renal proximal convoluted tubules.
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Multiple mammary epithelial cell (MEC) types are observed both in mammary ducts in vivo and in primary cultures in vitro; however, the oncogenic potential of different cell types remains unknown. Here, we used human papilloma virus 16 E6 and E7 oncogenes, which target p53 and Rb tumor suppressor proteins, respectively, to immortalize MECs present in early or late passages of human mammary tissue-derived cultures or in milk. One MEC subtype was exclusively immortalized by E6; such cells predominated in late-passage cultures but were rare at early passages and apparently absent in milk. Surprisingly, a second cell type, present only in early-passage tissue-derived cultures, was fully immortalized by E7 alone. A third cell type, observed in tissue-derived cultures and in milk, showed a substantial extension of life span with E7 but eventually senesced. Finally, both E6 and E7 were required to fully immortalize milk-derived MECs and a large proportion of MECs in early-passage tissue-derived cultures, suggesting the presence of another discrete subpopulation. Identification of MECs with distinct susceptibilities to p53- and Rb-targeting human papillomavirus oncogenes raises the possibility that these cells may serve as precursors for different forms of breast cancer.
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We give a partition of the critical strip, associated with each partial sum 1 + 2z + ... + nz of the Riemann zeta function for Re z < −1, formed by infinitely many rectangles for which a formula allows us to count the number of its zeros inside each of them with an error, at most, of two zeros. A generalization of this formula is also given to a large class of almost-periodic functions with bounded spectrum.
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This layer is a georeferenced raster image of the historic paper map entitled: Toonneel des oorlogs in't zuider deel van Europa, door Carel Allard = Theatre de la guerre dans l'Europe meridionale, par Charles Allard. It was published by C. Allard in 1705. Scale [ca. 1:6,800,000]. Covers a portion of Europe and the Mediterranean Sea region. This layer is image 2 of 2 total images of the two sheet source map, representing the eastern portion of the map. Map in Dutch and French. The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown pictorially.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.
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Seriocarpa rhizoides Diehl 1969 was collected in abundance from the calcareous sand of the Josephine Bank (between Portugal and Madeira) during the "Meteor" seamount cruises in 1967. Attachment in this loose soft substratum is effected by fine anchoring strands of the tests. Two irregular series of small polycarp-like hermaphrodite bodies which are embedded in a connective tissue lie directly below the endostyle, forming a tubular compound gonad, but without common ducts. The intermediate nature of the reproductive system with respect to arrangement and structure increases our knowledge about the polygenetic relations of the stylid-genera. Some of the hitherto known ecological facts point to the presumed "seamounts effect" on this species.
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bottom negative on strip
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bottom negative on strip
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Mode of access: Internet.
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Mode of access: Internet.
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"State-of-the Science Conference on Endoscopic Retrograde Cholangiopancreatography (ERCP) for Diagnosis and Therapy was convened on January 14-16, 2002"--P. 5.
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"Radiology of the gallbladder, by Ernest E. Smith": p. 84-104. "Diagnostic and therapeutic duodenal drainage, by Harry M. Eberhard": p. 105-136.
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Mode of access: Internet.
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"July, 1980."
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Funded by the U.S. Dept. of Interior, Office of Surface Mining Reclamation and Enforcement.
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Council chairman: Lt. Gov. Dave O'Neal.