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排序方式: 共有367条查询结果,搜索用时 31 毫秒
71.
I. Bryman S. Hammarstr m B. Lindblom A. Norstr m M. Wikland N. Wiqvist 《Prostaglandins & other lipid mediators》1985,30(6):907-913
Biopsies from different segments of the pregnant human uterus were superfused in organ chambers and contractile activity was registered. Leukotriene C4(LTC4) caused inhibition of spontaneous but not noradrenaline induced contractile activity in strips from the cervix. This effect occured both in early pregnancy and at term. However, the lower and the upper uterine segment of the term pregnant uterus did not respond to LTC4. The results represent a documentation of the segmental differentiation in the uterine response to eicosanoids. 相似文献
72.
Antisense Therapy for a Common Corneal Dystrophy Ameliorates TCF4 Repeat Expansion-Mediated Toxicity
Christina Zarouchlioti Beatriz Sanchez-Pintado Nathaniel J. Hafford Tear Pontus Klein Petra Liskova Kalyan Dulla Ma’ayan Semo Anthony A. Vugler Kirithika Muthusamy Lubica Dudakova Hannah J. Levis Pavlina Skalicka Pirro Hysi Michael E. Cheetham Stephen J. Tuft Peter Adamson Alison J. Hardcastle Alice E. Davidson 《American journal of human genetics》2018,102(4):528-539
73.
An Evaluation of Genetic Heterogeneity in 145 Breast-Ovarian Cancer Families 总被引:27,自引:11,他引:16
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Steven A. Narod Deborah Ford Peter Devilee Rosa B. Barkardottir Henry T. Lynch Simon A. Smith Bruce A. J. Ponder Barbara L. Weber Judy E. Garber Jill M. Birch Renee S. Cornelis David P. Kelsell Nigel K. Spurr Elizabeth Smyth Neva Haites Hagay Sobol Yves-Jean Bignon Jenny Chang-Claude Ute Hamann Annika Lindblom Ake Borg M. Steven Piver Holly H. Gallion Jeffrey P. Struewing Alice Whittemore Patricia Tonin David E. Goldgar Douglas F. Easton 《American journal of human genetics》1995,56(1):254-264
The breast-ovary cancer–family syndrome is a dominant predisposition to cancer of the breast and ovaries which has been mapped to chromosome region 17ql2-q21. The majority, but not all, of breast-ovary cancer families show linkage to this susceptibility locus, designated BRCA1. We report here the results of a linkage analysis of 145 families with both breast and ovarian cancer. These families contain either a total of three or more cases of early-onset (before age 60 years) breast cancer or ovarian cancer. All families contained at least one case of ovarian cancer. Overall, an estimated 76% of the 145 families are linked to the BRCA1 locus. None of 13 families with cases of male breast cancer appear to be linked, but it is estimated that 92% (95% confidence interval 76%–100%) of families with no male breast cancer and with two or more ovarian cancers are linked to BRCA1. These data suggest that the breast-ovarian cancer–family syndrome is genetically heterogeneous. However, the large majority of families with early-onset breast cancer and with two or more cases of ovarian cancer are likely to be due to BRCA1 mutations. 相似文献
74.
Tumorigenesis in colorectal tumors from patients with hereditary non-polyposis colorectal cancer 总被引:10,自引:0,他引:10
Tumorigenesis of colorectal cancer in patients with hereditary non-polyposis colorectal cancer (HNPCC) has been postulated
to follow a different pathway from that of sporadic colorectal tumors. A characteristic of HNPCC-associated tumors is the
replication error phenotype. We studied tumorigenesis in 8 fresh-frozen and 67 paraffin-embedded colorectal tumors derived
from 29 families with HNPCC or a familial aggregation of colorectal cancer. By using intragenic markers, inactivation of the
wild-type allele of hMLH1 was shown to occur through loss of heterozygosity and not through a somatic point mutation. Microsatellite instability is
very common and occurs early in almost all colorectal tumors from HNPCC patients. Transforming growth factor β type II receptor
(TβRII) mutations occur in these tumors at a high frequency. Of colorectal cancers from families with HNPCC, 63% have frameshift
mutations in TβRII, compared with 10% of sporadic colorectal cancers. APC and K-RAS mutations appear to be as frequent in the HNPCC tumors as in the sporadic counterpart.
Received: 3 March 1997 / Accepted: 23 June 1997 相似文献
75.
Phase equilibria of membrane lipids from Acholeplasma laidlawii: importance of a single lipid forming nonlamellar phases 总被引:6,自引:0,他引:6
A basis for the reorganization of the bilayer structure in biological membranes is the different aggregate structures formed by lipids in water. The phase equilibria of all individual lipids and several in vivo polar lipid mixtures from acyl chain modified membranes of Acholeplasma laidlawii were investigated with different NMR techniques. All dioleoyl (DO) polar lipids, except monoglucosyldiglyceride (MGDG), form lamellar liquid crystalline (L alpha) phases only. The phase diagram of DOMGDG reveals reversed cubic (III), reversed hexagonal (HII), and L alpha phases. In mixtures of DOMGDG and dioleoyldiglycosyldiglyceride (DODGDG), the formation of an III (or HII) phase is enhanced by DOMGDG and low hydration or high temperatures. For in vivo mixtures of all polar DO lipids, a transition from an L alpha to an III phase is promoted by low hydration or high temperatures (50 degrees C). The phospholipids are incorporated in this III phase. Likewise, III and HII phases are formed at similar temperatures in a series of in vivo mixtures with different extents of acyl chain unsaturation. However, their melting temperatures (Tm) vary in an expected manner. All cubic and hexagonal phases, except the III phase with DOMGDG, exist in equilibrium with excess water. The maximum hydration of MGDG and DGDG is similar and increases with acyl chain unsaturation but is substantially lower than that for, e.g., phosphatidylcholine. The translational diffusion of the lipids in the cubic phases is rapid, implying bicontinuous structures. However, their appearances in freeze-fracture electron microscope pictures are different. The III phase of DOMGDG belongs to the Ia3d space group.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
76.
The effect of prostaglandin I on the contractility of the term pregnant human myometrium 总被引:1,自引:0,他引:1
Small myometrial strips were dissected from the upper and lower segments of the term pregnant human uterus. The specimens were superfused in organ chambers and contractile activity was recorded isometrically. In strips from the upper segment, prostacyclin (PGI2), induced an initial excitatory response followed in the majority of experiments by transient inhibition. In the lower segment the response was generally the same although direct inhibition without initial stimulation occurred in some cases. During the period of inhibition the specimens were refractory to iterated exposure to PGI2. Furthermore, during this period of PGI2-induced inhibition the muscle strip was also refractory to PGE2 but responded to PGF2 alpha and oxytocin by stimulation. After inhibition of spontaneous contractile activity induced by indomethacin PGI2 induced an excitatory response. The results do not indicate any critical change in the myometrial responsiveness of the upper uterine segment to PGI2 during labor. In strips from the lower segment obtained before labor there tended to be a dominance of non-responders and inhibition only as compared to the results during labor. Nevertheless, whether or not PGI2 under physiological or pharmacological conditions has any significant influence on the contractility of the term pregnant human uterus, still remains obscure. As judged from earlier reports from our laboratory and the present study it is evident that the uterine vessels are considerably more sensitive to the action of PGI2 than the myometrium. 相似文献
77.
Multicomponent self-diffusion data on dioleoyl(DOL)- and dipalmitoyllecithin (DPL) vesicle-water systems have been determined using a Fourier transform NMR technique. The self-diffusion of vesicles is characterized by diffusion coefficients two magnitudes lower than that of small molecules in solution. Consequently, the degree of binding of small molecules is strongly reflected in their time-averaged self-diffusion coefficient in vesicle-water systems. This provides a new basis for the determination of vesicle-water partition equilibria. The feasibility of the technique has been investigated in one anesthetic-lipid system and is found to be very good. The binding of the hydrochloride form of tetracaine to DOL vesicles at pH 3 and 7 (Kp = 30–50) is found to be very much lower than that of the neutral molecule at pH 9 (Kp = 800–900). No significant difference in the tetracaine binding characteristics was found between DOL, DOL-cholesterol and DPL systems. 相似文献
78.
Disulfide bonds in alpha 2-macroglobulin (alpha 2M) were reduced with the thioredoxin system from Escherichia coli. Under the conditions selected, 3.5-4.1 disulfide bonds were cleaved in each alpha 2M molecule, as determined by the consumption of NADPH during the reaction and by the incorporation of iodo[3H]acetate into the reaction product. This extent of disulfide bond reduction, approximately corresponding to that expected from specific cleavage of all four interchain disulfide bonds of the protein, coincided with the nearly complete dissociation of the intact alpha 2M molecule to a species migrating as an alpha 2M subunit in gel electrophoresis, under both denaturing and nondenaturing conditions. The dissociation was accompanied by only small changes of the spectroscopic properties of the subunits, which thus retain a near-native conformation. Reaction of isolated subunits with methylamine or trypsin led to the appearance of approximately 0.55 mol of thiol group/mol of subunits, indicating that the thio ester bonds are largely intact. Moreover, the rate of cleavage of these bonds by methylamine was similar to that in the whole alpha 2M molecule. Although the bait region was specifically cleaved by nonstoichiometric amounts of trypsin, the isolated subunits had minimal proteinase binding ability. Reaction of subunits with methylamine or trypsin produced changes of farultraviolet circular dichroism and near-ultraviolet absorption similar to those induced in the whole alpha 2M molecule, although in contrast with whole alpha 2M no fluorescence change was observed. The methylamine- or trypsin-treated subunits reassociated to a tetrameric species, migrating as the "fast" form of whole alpha 2M in gradient gel electrophoresis.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
79.
Reversed hexagonal phase formation in lecithin-alkane-water systems with different acyl chain unsaturation and alkane length 总被引:4,自引:0,他引:4
Investigations of lipid-alkane systems are important for an understanding of the interactions between lipids and hydrophobic/amphiphilic peptides or other hydrophobic biological molecules. A study of the formation of nonlamellar phases in several phosphatidylcholine (PC)-alkane-2H2O systems has been performed. The PC molecules chosen in this work are dipalmitoyl-PC (DPPC), 1-palmitoyl-2-oleoyl-PC (POPC), dioleoyl-PC (DOPC), and dilinoleoyl-PC (DLiPC), lipids that in excess water form just a lamellar liquid-crystalline phase up to at least 90 degrees C. The addition of n-alkanes (C8-C20) to these PC-2H2O systems induces the formation of reversed hexagonal (HII) and isotropic phases. The water and dodecane concentrations required to form these phases depend on the degree of acyl chain unsaturation of the PC molecules and increase in the order DLiPC approximately DOPC less than POPC less than DPPC. The most likely explanation to this result is that the diameter of the lipid-water cylinders in the HII phase grows gradually larger with increased acyl chain saturation and more water and dodecane are consequently needed to fill the water cylinders and the void volumes between the cylinders, respectively. The ability of the alkanes to promote the formation of an HII phase is strongly chain length dependent. Although the number of alkane carbon atoms added per DOPC molecule in the DOPC-n-alkane-2H2O mixtures was kept constant, this ability decreased on going from octane to eicosane. The thermal history of a DPPC-n-dodecane-2H2O sample was important for its phase behavior.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
80.
Stoichiometry of reactions of alpha 2-macroglobulin with trypsin and chymotrypsin. 总被引:1,自引:1,他引:0
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The stoichiometry of the individual steps, i.e. polypeptide chain cleavage, hydrolysis of the putative thioester bond and conformational change, of the reaction between alpha 2-macroglobulin and trypsin or chymotrypsin was analysed. The chain cleavage was monitored by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the thioester hydrolysis by both a spectroscopic and a fluorimetric technique and the conformational change by tryptophan fluorescence. A stoichiometry of close to 2:1 was obtained for all reactions. This finding indicates that the alpha 2-macroglobulin half-molecule is an independent functional unit of the inhibitor, within which co-operativity between the two subunits may occur. 相似文献