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An increase in intermediate filaments has been reported in rat uterine stromal cells undergoing decidualization in vivo and in vitro. In order to identify biochemical correlates of this morphological change, we have identified (two dimensional gel electrophoresis, Western blots, indirect immunofluorescent staining) the constitutive intermediate filament proteins of stromal cells decidualizing in vivo and isolated stroma decidualizing in vitro as vimentin and desmin. Vimentin is common to all uterine stromal cells but increases, proportional to total cell protein, in decidualized stroma. Barely detectable in nondecidualized stroma, desmin, unlike vimentin, increases during decidualization at a rate greater than the increase in total cell protein. Neither the increase in vimentin or desmin is observed in hormonally sensitized, nondecidual stromal cells. Desmin, because it is selectively expressed in decidualizing stroma, could be considered unique enough to serve as a marker of decidual cell differentiation. 相似文献
83.
Flow dialysis measurements of calcium binding to bovine brain S100 alpha alpha, S100a (alpha beta), and S100b (beta beta) proteins in 20 mM Tris-HCl buffer at pH 7.5 and 8.3 revealed that S100 proteins bind specifically 4 Ca2+ eq/mol of protein dimer. The specific calcium-binding sites had, therefore, been assigned to typical amino acid sequences on the alpha and beta subunit. The protein affinity for calcium is much lower in the presence of magnesium and potassium. Potassium strongly antagonizes calcium binding on two calcium-binding sites responsible for most of the Ca2+-induced conformational changes on S100 proteins (probably site II alpha and site II beta). Zinc-binding studies in the absence of divalent cations revealed eight zinc-binding sites/mol of S100b protein dimer that we assumed to correspond to 4 zinc-binding sites/beta subunit. Zinc binding to S100b studied with UV spectroscopy methods showed that the occupation of the four higher affinity sites and the four lower affinity sites on the protein dimer were responsible for different conformational changes in S100b structure. Zinc binding on the higher affinity sites regulates calcium binding to S100b by increasing the protein affinity for calcium and decreasing the antagonistic effect of potassium on calcium binding. Zinc-binding studies on S100a and S100 alpha alpha protein showed that the Trp-containing S100 proteins bind zinc more weakly than S100b protein. Calcium-binding studies on zinc-bound S100a proved that calcium- and zinc-binding sites were distinct although there was no increase in zinc-bound S100a affinity for calcium, as in S100b protein. Finally we provide evidence that discrepancies between previously published results on the optical properties of S100b protein probably result from oxidation of the sulfhydryl groups in the protein. 相似文献
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In vitro interaction of premazepam with benzodiazepine receptors in rat brain regions 总被引:1,自引:0,他引:1
Premazepam (PRZ) in vitro competitively displaced 3H-diazepam (DIA), 3H-flunitrazepam (FLU) and 3H-RO 15-1788 from their binding sites on rat brain synaptosomes, with a potency intermediate to other benzodiazepines (BDZs), and Hill coefficients near 1 in different brain regions. Incubation at 37 degrees C reduced premazepam's affinity for BDZ receptors to a lower extent than other benzodiazepines and had no effect on the Hill coefficient. The IC50 of PRZ on 3H-RO 15-1788 and 3H-FLU binding was markedly reduced by GABA in rat cortex, like those of reference classical BDZs, but was GABA-independent in the cerebellum. The IC50 of the BDZ antagonist, RO 15-1788 was unaffected by GABA in both brain areas. The possibility that PRZ behaves as a partial agonist in the cortex and as an antagonist in the cerebellum is discussed. 相似文献
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Multiplexed echo planar imaging for sub-second whole brain FMRI and fast diffusion imaging 总被引:2,自引:0,他引:2
Feinberg DA Moeller S Smith SM Auerbach E Ramanna S Gunther M Glasser MF Miller KL Ugurbil K Yacoub E 《PloS one》2010,5(12):e15710
Echo planar imaging (EPI) is an MRI technique of particular value to neuroscience, with its use for virtually all functional MRI (fMRI) and diffusion imaging of fiber connections in the human brain. EPI generates a single 2D image in a fraction of a second; however, it requires 2-3 seconds to acquire multi-slice whole brain coverage for fMRI and even longer for diffusion imaging. Here we report on a large reduction in EPI whole brain scan time at 3 and 7 Tesla, without significantly sacrificing spatial resolution, and while gaining functional sensitivity. The multiplexed-EPI (M-EPI) pulse sequence combines two forms of multiplexing: temporal multiplexing (m) utilizing simultaneous echo refocused (SIR) EPI and spatial multiplexing (n) with multibanded RF pulses (MB) to achieve m×n images in an EPI echo train instead of the normal single image. This resulted in an unprecedented reduction in EPI scan time for whole brain fMRI performed at 3 Tesla, permitting TRs of 400 ms and 800 ms compared to a more conventional 2.5 sec TR, and 2-4 times reductions in scan time for HARDI imaging of neuronal fibertracks. The simultaneous SE refocusing of SIR imaging at 7 Tesla advantageously reduced SAR by using fewer RF refocusing pulses and by shifting fat signal out of the image plane so that fat suppression pulses were not required. In preliminary studies of resting state functional networks identified through independent component analysis, the 6-fold higher sampling rate increased the peak functional sensitivity by 60%. The novel M-EPI pulse sequence resulted in a significantly increased temporal resolution for whole brain fMRI, and as such, this new methodology can be used for studying non-stationarity in networks and generally for expanding and enriching the functional information. 相似文献
89.
Godet J de Rocquigny H Raja C Glasser N Ficheux D Darlix JL Mély Y 《Journal of molecular biology》2006,356(5):1180-1192
90.
Longchuan Li Todd M. Preuss James K. Rilling William D. Hopkins Matthew F. Glasser Bhargav Kumar Roger Nana Xiaodong Zhang Xiaoping Hu 《PloS one》2010,5(9)