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Hans-Werner Mueller Armin Michel Dirk Heckel Ulrike Fischer Monika Tönnes Lap-Chee Tsui Steven Scherer Klaus D. Zang E. Meese 《Human genetics》1997,101(2):190-197
Gene amplification, which occurs in more than 50% of malignant gliomas, is considered to play a pivotal role in tumorigenesis.
There are, however, few studies aimed toward the isolation of novel genes from amplified sequences. Previously, we reported
amplification of the protooncogene MET (hepatocyte growth factor receptor; 7q31) in more than 20% of glioblastomas. For an
approximate size estimation of the amplification unit we analyzed three glioblastomas all of which carried an amplified MET
gene, by Southern blot analysis and/or competitive polymerase chain reaction using eight DNA markers. Although the extent
of the amplified domain varied, the close vicinity of the MET gene was the only region consistently amplified in these glioblastomas.
A yeast artificial chromosome (YAC) contig of 900 kb was refined spanning the amplified region flanking the MET gene. The
YAC inserts were subcloned into 59 cosmids, which were used for exon trapping. Eight sequences were identical to parts of
the genes MET and CAPZA2 (human actin capping protein α-subunit). Two newly identified exons and the CAPZA2 exons were amplified
in tumor TX3095, which retains an amplified MET gene. The new exons were localized close to MET and CAPZA2. Characterization
of the clones, which were termed glioma-amplified sequence (GAS)7-1 and GAS7-2, showed an open reading frame and a different
expression pattern in multiple human tissues. This study reports the identification of a cluster of amplified genes including
two novel genes in a region amplified in more than 20% of glioblastomas.
Received: 27 June 1997 / Accepted: 18 July 1997 相似文献
995.
996.
Many algae, particularly microalgae, possess a sophisticated light-sensing system including photoreceptors and light-modulated signaling pathways to sense environmental information and secure the survival in a rapidly changing environment. Over the last couple of years, the multifaceted world of algal photobiology has enriched our understanding of the light absorption mechanisms and in vivo function of photoreceptors. Moreover, specific light-sensitive modules have already paved the way for the development of optogenetic tools to generate light switches for precise and spatial control of signaling pathways in individual cells and even in complex biological systems. 相似文献
997.
Pierre Vauclare Richard Bligny Elisabeth Gout Valentine De Meuron François Widmer 《Planta》2010,231(6):1495-1504
The effects of dark-induced stress on the evolution of the soluble metabolites present in senescent soybean (Glycine max L.) nodules were analysed in vitro using 13C- and 31P-NMR spectroscopy. Sucrose and trehalose were the predominant soluble storage carbons. During dark-induced stress, a decline
in sugars and some key glycolytic metabolites was observed. Whereas 84% of the sucrose disappeared, only one-half of the trehalose
was utilised. This decline coincides with the depletion of Gln, Asn, Ala and with an accumulation of ureides, which reflect
a huge reduction of the N2 fixation. Concomitantly, phosphodiesters and compounds like P-choline, a good marker of membrane phospholipids hydrolysis
and cell autophagy, accumulated in the nodules. An autophagic process was confirmed by the decrease in cell fatty acid content.
In addition, a slight increase in unsaturated fatty acids (oleic and linoleic acids) was observed, probably as a response
to peroxidation reactions. Electron microscopy analysis revealed that, despite membranes dismantling, most of the bacteroids
seem to be structurally intact. Taken together, our results show that the carbohydrate starvation induced in soybean by dark
stress triggers a profound metabolic and structural rearrangement in the infected cells of soybean nodule which is representative
of symbiotic cessation. 相似文献
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999.
René P. Widmer Soyka Benedikt Helgason Javad Hazrati Marangalou Joop P. van den Bergh Bert van Rietbergen Stephen J. Ferguson 《PloS one》2016,11(4)
PurposeVertebral fragility fractures are often treated by injecting bone cement into the collapsed vertebral bodies (vertebroplasty). The mechanisms by which vertebroplasty induces pain relief are not completely understood yet and recent debates cast doubt over the outcome of the procedure. The controversy is intensified by inconsistent results of randomized clinical trials and biomechanical studies that have investigated the effectiveness or the change in biomechanical response due to the reinforcement. The purpose of this study was to evaluate the effectiveness of vertebroplasty, by varying the relevant treatment parameters and (a) computationally predicting the improvement of the fracture risk depending on the chosen treatment strategy, and (b) identifying the determinants of a successful treatment.MethodsA Finite Element model with a patient-specific failure criterion and direct simulation of PMMA infiltration in four lumbar vertebrae was used to assess the condition of the bone under compressive load before and after the virtual treatment, simulating in a total of 12000 virtual treatments.ResultsThe results showed that vertebroplasty is capable of reducing the fracture risk by magnitudes, but can also have a detrimental effect. Effectiveness was strongly influenced by interactions between local bone quality, cement volume and injection location. However, only a moderate number of the investigated treatment strategies were able to achieve the necessary improvement for preventing a fracture.ConclusionsWe conclude that the effectiveness of vertebroplasty is sensitive to the patient’s condition and the treatment strategy. 相似文献
1000.
Erfan Salahinejad Mohammad Jafar Hadianfard Digby Donald Macdonald Samin Sharifi-Asl Masoud Mozafari Kenneth J. Walker Armin Tahmasbi Rad Sundararajan V. Madihally Lobat Tayebi 《PloS one》2013,8(4)
The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen''s structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments. 相似文献