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61.
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Juan Dong Jenny Chang-Claude Yixin Wu Valérie Schumacher Irmgard Debatin Patricia Tonin Brigitte Royer-Pokora 《Human genetics》1998,103(2):154-161
We have analyzed 61 German breast and breast/ovarian cancer families for BRCA1 mutations using single-strand conformation
polymorphism analysis (SSCP) followed by sequencing. Forty-seven of the families had at least three cases (at least two under
60 years) and 14 families had only two cases of breast/ovarian cancer (at least one under 50 years). Twenty-eight families
were breast/ovarian and 33 were breast cancer-only families. Eighteen mutations in BRCA1 were detected in 11/28 breast/ovarian
cancer families and 7/33 breast cancer families and none in the families with only two cases. We identified 17 truncation
mutations (8 frameshift, 7 nonsense and 2 splice variants) and one missense mutation. Seven of these are novel and two, the
5382insC and 5622C→T mutations, occurred in two apparently unrelated families. The genotype of the two families with the 5382insC
mutation is compatible with the rare haplotype segregating with the 5382insC mutation in different populations, further supporting
its European origin. One unclassified missense alteration, R841W, was found in one family but did not segregate with the disease,
suggesting that it is more likely a polymorphism. We also report and discuss the sequence of several new unclassified single-nucleotide
changes first identified by SSCP. Of the 18 mutations, 13 occurred in the 3′ third of the gene (end of exon 11–24) and ovarian
cancers were found in eight of these families.
Received: 5 February 1998 / Accepted: 7 April 1998 相似文献
64.
Irmgard Ziegler 《Phytochemistry》1974,13(11):2403-2410
Sephadex G-200 gel filtration of an ammonium sulfate fraction, containing the bulk of NAD-dependent malate dehydrogenase, yields forms of differing MW. Both Mg2+ and NADH stabilize the 127000 daltons MW form. K+, or incubation with dithioerythritol, cause splitting and partial reaggregation, resulting in MWs ranging between 35000 and 180000 daltons. Chromatography in the presence of dithioerythritol and NADH results in an enzyme with a non-linear reaction rate at low substrate concentrations. Plots of initial velocity vs substrate and cofactor concentration respectively are characterized by two slopes of positive cooperativity separated by an intermediary plateau of negative cooperativity. Gel chromatography in the presence of Mg2+ or K+ or drastic dilution of the enzyme results in an enzyme with linear reaction rates also at low substrate concentration. Its kinetics are consistent with the view that the enzyme undergoes conformational changes when the substrate concentration is varied. 相似文献
65.
Ziegler Hubert Ziegler Irmgard 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1957,40(6):549-555
Ohne ZusammenfassungDer Deutschen Forschungsgemeinschaft sind wir für ihre Unterstützung, Herrn Prof. Dr. A. Koch für Literaturhinweise zu Dank verpflichtet. 相似文献
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Potato Shoot and Tuber Cultures In Vitro 总被引:2,自引:0,他引:2
68.
Mire Convery Caitríona Dennis Sin Rowsell Andreas Engel J Bernard Heymann Gary Parkinson Rob Russell Gianfranco Gilardi Richard Newman Irmgard Sinning Sabine Flitsch Philip AS Lowden Steve Matthews Gerard J Kleywegt Jon D Stewart 《Current opinion in structural biology》1999,9(6):653
A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in structural biology. 相似文献
69.
70.
Ivan N. Rich Irmgard Brackmann Diana Worthington-White Michael J. Dewey 《Journal of cellular physiology》1998,177(1):109-122
The proliferative response of hematopoietic cells is regulated by many factors, including the presence and type of growth factors, the cellular microenvironment, and the physiochemical conditions prevailing in the tissue milieu. A process fundamental to all cells is the regulation of the intracellular acid-base conditions. One of the mechanisms by which intracellular pH (pHi) is regulated is through the sodium/hydrogen exchanger, a ubiquitous membrane protein which exploits the intra- and extracellular sodium ion gradient to drive hydrogen ions out of the cell. However, activation of the exchanger via mitogenic and nonmitogenic signals leads to an increase in pHi which, in turn, may directly or indirectly result in a proliferative response. It has been shown that interaction of fibronectin with its integrin receptor subunits α4 and α5 can result in activation of the Na+/H+ exchanger. In this report, we demonstrate that when mouse bone marrow cells are physically brought together in a preculture system we designate as high cell density culture (HCDC), in a small volume and at the same cellularity as that in the marrow, hematopoietic stem and progenitor cell populations are stimulated with no additional stimulation in the presence of growth factors. Neutralizing antibodies to the growth factors added to HCDC had little, if any, effect on the degree of stimulation. However, when antibodies to fibronectin or the α4 integrin subunit were added to HCDC, inhibition was observed, indicating that the observed hematopoietic stimulation occurred via the fibronectin-integrin pathway. Addition of 5 μM 5-(N,N-hexamethylene) amiloride (5-HMA), a specific inhibitor of the Na+/H+ exchanger, also resulted in inhibition of in vitro hematopoiesis. Since the exchanger was implicated, we then measured the pHi of normal and HCDC-treated bone marrow cells in the absence and presence of 5-HMA by flow cytometry using the fluorescent pH-sensitive indicator, carboxy SNARF-1 AM. It was found that cells subjected to HCDC exhibited a higher pHi than normal fresh cells. In each case, the pHi was lowered in the presence of 5-HMA. Furthermore, addition of antibodies to fibronectin or the α4 integrin subunit to HCDC also reduced the pHi to a similar level to that found for 5-HMA. Our results demonstrate, for the first time, that a hematopoietic stem and progenitor cell proliferative response can be initiated by activation of the Na+/H+ exchanger, leading to an increase in pHi, via cell-cell interaction through the fibronectin-integrin pathway. This pathway could, therefore, be significant not only in normal hematopoietic regulation, but also under pathophysiological conditions. J. Cell. Physiol. 177:109–122, 1998. © 1998 Wiley-Liss, Inc. 相似文献