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1.
Balagopal P Pandey M Chandramohan K Somanathan T Kumar A 《World journal of surgical oncology》2003,1(1):4
Background
Choriocarcinoma is an aggressive neoplasm arising in the body of the uterus. The disease normally spreads to lung and brain. 相似文献2.
Introduction
Development of cell therapies for repairing the intervertebral disc is limited by the lack of a source of healthy human disc cells. Stem cells, particularly mesenchymal stem cells, are seen as a potential source but differentiation strategies are limited by the lack of specific markers that can distinguish disc cells from articular chondrocytes. 相似文献3.
D Taruscio C Morciano P Laricchiuta P Mincarone F Palazzo CG Leo S Sabina R Guarino J Auld T Sejersen D Gavhed K Ritchie M Hilton-Boon J Manson PG Kanavos D Tordrup V Tzouma Y Le Cam J Senecat G Filippini S Minozzi C Del Giovane H Schünemann JJ Meerpohl B Prediger L Schell R Stefanov G Iskrov T Miteva-Katrandzhieva P Serrano-Aguilar L Perestelo-Perez MM Trujillo-Martín J Pérez-Ramos A Rivero-Santana A Brand H van Kranen K Bushby A Atalaia J Ramet L Siderius M Posada I Abaitua-Borda V Alonso Ferreira M Hens-Pérez FJ Manzanares 《Orphanet journal of rare diseases》2014,9(Z1):O14
4.
Ana C. Coan Brunno M. Campos Clarissa L. Yasuda Bruno Y. Kubota Felipe PG. Bergo Carlos AM. Guerreiro Fernando Cendes 《PloS one》2014,9(1)
Objective
Patients with temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS) have diffuse subtle gray matter (GM) atrophy detectable by MRI quantification analyses. However, it is not clear whether the etiology and seizure frequency are associated with this atrophy. We aimed to evaluate the occurrence of GM atrophy and the influence of seizure frequency in patients with TLE and either normal MRI (TLE-NL) or MRI signs of HS (TLE-HS).Methods
We evaluated a group of 172 consecutive patients with unilateral TLE-HS or TLE-NL as defined by hippocampal volumetry and signal quantification (122 TLE-HS and 50 TLE-NL) plus a group of 82 healthy individuals. Voxel-based morphometry was performed with VBM8/SPM8 in 3T MRIs. Patients with up to three complex partial seizures and no generalized tonic-clonic seizures in the previous year were considered to have infrequent seizures. Those who did not fulfill these criteria were considered to have frequent seizures.Results
Patients with TLE-HS had more pronounced GM atrophy, including the ipsilateral mesial temporal structures, temporal lobe, bilateral thalami and pre/post-central gyri. Patients with TLE-NL had more subtle GM atrophy, including the ipsilateral orbitofrontal cortex, bilateral thalami and pre/post-central gyri. Both TLE-HS and TLE-NL showed increased GM volume in the contralateral pons. TLE-HS patients with frequent seizures had more pronounced GM atrophy in extra-temporal regions than TLE-HS with infrequent seizures. Patients with TLE-NL and infrequent seizures had no detectable GM atrophy. In both TLE-HS and TLE-NL, the duration of epilepsy correlated with GM atrophy in extra-hippocampal regions.Conclusion
Although a diffuse network GM atrophy occurs in both TLE-HS and TLE-NL, this is strikingly more evident in TLE-HS and in patients with frequent seizures. These findings suggest that neocortical atrophy in TLE is related to the ongoing seizures and epilepsy duration, while thalamic atrophy is more probably related to the original epileptogenic process. 相似文献5.
6.
Structural determinants responsible for the substrate preference of the potassium-independent (ASPGA1) and -dependent (ASPGB1)
asparaginases from Arabidopsis thaliana have been investigated. Like ASPGA1, ASPGB1 was found to be catalytically active with both l-Asn and β-Asp-His as substrates, contrary to a previous report. However, ASPGB1 had a 45-fold higher specific activity with
Asn as substrate than ASPGA1. A divergent sequence between the two enzymes forms a variable loop at the C-terminal of the
alpha subunit. The results of dynamic simulations have previously implicated a movement of the C-terminus in the allosteric
transduction of K+-binding at the surface of LjNSE1 asparaginase. In the crystal structure of Lupinus luteus asparaginase, most residues in this segment cannot be visualized due to a weak electron density. Exchanging the variable
loop in ASPGA1 with that from ASPGB1 increased the affinity for Asn, with a 320-fold reduction in K
m value. Homology modeling identified a residue specific to ASPGB1, Phe162, preceding the variable loop, whose side chain is located in proximity to the beta-carboxylate group of the product aspartate,
and to Gly246, a residue participating in an oxyanion hole which stabilizes a negative charge forming on the side chain oxygen of asparagine
during catalysis. Replacement with the corresponding leucine from ASPGA1 specifically lowered the V
max value with Asn as substrate by 8.4-fold. 相似文献
7.
Cornelia Tolg Sara R. Hamilton Lyndsey Morningstar Jing Zhang S. Zhang Kenneth V. Esguerra Patrick G. Telmer Len G. Luyt Rene Harrison James B. McCarthy Eva A. Turley 《The Journal of biological chemistry》2010,285(34):26461-26474
An oncogenic form of RHAMM (receptor for hyaluronan-mediated motility, mouse, amino acids 163–794 termed RHAMMΔ163) is a cell surface hyaluronan receptor and mitotic spindle protein that is highly expressed in aggressive human cancers. Its regulation of mitotic spindle integrity is thought to contribute to tumor progression, but the molecular mechanisms underlying this function have not previously been defined. Here, we report that intracellular RHAMMΔ163 modifies the stability of interphase and mitotic spindle microtubules through ERK1/2 activity. RHAMM−/− mouse embryonic fibroblasts exhibit strongly acetylated interphase microtubules, multi-pole mitotic spindles, aberrant chromosome segregation, and inappropriate cytokinesis during mitosis. These defects are rescued by either expression of RHAMM or mutant active MEK1. Mutational analyses show that RHAMMΔ163 binds to α- and β-tubulin protein via a carboxyl-terminal leucine zipper, but in vitro analyses indicate this interaction does not directly contribute to tubulin polymerization/stability. Co-immunoprecipitation and pulldown assays reveal complexes of RHAMMΔ163, ERK1/2-MEK1, and α- and β-tubulin and demonstrate direct binding of RHAMMΔ163 to ERK1 via a D-site motif. In vitro kinase analyses, expression of mutant RHAMMΔ163 defective in ERK1 binding in mouse embryonic fibroblasts, and blocking MEK1 activity collectively confirm that the effect of RHAMMΔ163 on interphase and mitotic spindle microtubules is mediated by ERK1/2 activity. Our results suggest a model wherein intracellular RHAMMΔ163 functions as an adaptor protein to control microtubule polymerization during interphase and mitosis as a result of localizing ERK1/2-MEK1 complexes to their tubulin-associated substrates. 相似文献
8.
A. D. Clarke † A. Lewis ‡ K. H. Telmer § J. M. Shrimpton 《Journal of fish biology》2007,71(5):1479-1493
Trace element and fork length ( L F ) frequency analyses of eulachon Thaleichthys pacificus otoliths were used to determine age at maturity and repeat spawning potential, two aspects of eulachon life history that are not known but are important for successful management of this species. The L F -frequency analysis for ocean caught and spawning eulachon was used to estimate age at maturation. Two size classes of eulachon were caught in the ocean and spawning eulachon were consistently the largest fish indicating that spawners from mid-coast of British Columbia were 3 years old. Laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) was also used to reconstruct the Ba:Ca and Sr:Ca molar ratios deposited spatially into the otolith to estimate spawner age for five populations of eulachon. Age at maturation differed among populations examined. Based on the seasonal fluctuations in Ba:Ca molar ratios caused by seasonal upwelling of deep waters, it was determined that more southerly populations spawned at a younger age than the northern populations examined. Southern populations of eulachon, Columbia River, Washington, U.S.A., spawn after 2 years. Eulachon from the Fraser, Kemano and Skeena Rivers in British Columbia, Canada, generally mature after 3 years. Some Skeena River eulachon and most of the eulachon from the Copper River, Alaska, U.S.A., matured after 4 years. In contrast to the Ba:Ca molar ratios in the otolith, Sr:Ca molar ratios maintained a relatively flat profile over the life of the eulachon. The lack of a change in Sr:Ca ratios within the otolith, the single size class of spawners across all systems and the single age class within most populations strongly suggest that eulachon in the present study are semelparous. 相似文献
9.
Microspore development inBrassica napus and the effect of high temperature on division in vivo and in vitro 总被引:1,自引:0,他引:1
Summary
Brassica napus cv. Topas microspores isolated and cultured near the first pollen mitosis and subjected to a heat treatment develop into haploid embryos at a frequency of about 20%. In order to obtain a greater understanding of the induction process and embryogenesis, transmission electron microscopy was used to study the development of pollen from the mid-uninucleate to the bicellular microspore stage. The effect of 24 h of high temperature (32.5 °C) on microspore development was examined by heat treating microspore cultures or entire plants. Mid-uninucleate microspores contained small vacuoles. Late-uninucleate vacuolate microspores contained a large vacuole. The large vacuole of the vacuolate stage was fragmented into numerous small vacuoles in the late-uninucleate stage. The late-uninucleate stage contained an increased number of ribosomes, a pollen coat covering the exine and a laterally positioned nucleus. Prior to the first pollen mitosis the nucleus of the lateuninucleate microspore appeared to be appressed to the plasma membrane; numerous perinuclear microtubules were observed. Microspores developing into pollen divided asymmetrically to form a large vegetative cell with amyloplasts and a small generative cell without plastids. The cells were separated by a lens-shaped cell wall which later diminished. At the late-bicellular stage the generative cell was observed within the vegetative cell. Starch and lipid reserves were present in the vegetative cell and the rough endoplasmic reticulum and Golgi were abundant. The microspore isolation procedure removed the pollen coat, but did not redistribute or alter the morphology of the organelles. Microspores cultured at 25 °C for 24 h resembled late-bicellular microspores except more starch and a thicker intine were present. A more equal division of microspores occurred during the 24 h heat treatment (32.5 °C) of the entire plant or of cultures. A planar wall separated the cells of the bicellular microspores. Both daughter cells contained plastids and the nuclei were of similar size. Cultured embryogenie microspores contained electron-dense deposits at the plasma membrane/cell wall interface, vesicle-like structures in the cell walls and organelle-free regions in the cytoplasm. The results are related to embryogenesis and a possible mechanism of induction is discussed.Abbreviations B
binucleate
- LU
late uninucleate
- LUV
late uninucleate vacuolate
- M
mitotic
- MU
mid-uninucleate
- RER
rough endoplasmic reticulum
- TEM
transmission electron micrograph 相似文献
10.