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121.
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Aubrey D. N. J. de Grey 《Age (Dordrecht, Netherlands)》2005,27(2):129-138
The plasma membrane redox system (PMRS) is an electron transport chain in the plasma membrane that transfers electrons from
either intra- or extracellular donors to extracellular acceptors. Unlike the superoxide-generating NADPH oxidase of phagocytes
and the homologous (but much less active) enzymes found in some other cells, the PMRS is still incompletely characterised
at the molecular level. Much is known, however, concerning its function and affinity for both physiological and non-physiological
substrates. A role for it in aging, the ‘reductive hotspot hypothesis’ (RHH), was proposed in 1998 as part of an explanation
for the apparently indefinite survival in vivo of cells that have entirely lost mitochondrial respiratory capacity as a result of the accumulation of mitochondrial mutations.
Stimulation of the PMRS might allow the cell to maintain redox homeostasis even while continuing to operate the Krebs cycle,
which may be advantageous in many ways. However, the PMRS may, like the mitochondrial respiratory chain, be prone to generate
superoxide when thus dysregulated – and in this case superoxide would be generated outside the cell, where antioxidant defences
are more limited than inside the cell and where much highly oxidisable material is present. Cascades of peroxidation chain
reactions initiated by this process may greatly amplify the oxidative stress on the organism that is caused by rare mitochondrially
mutant cells. Since such cells increase in abundance with aging (though remaining rare), this is an economical hypothesis
to explain the rise in oxidative stress seen in (and generally believed to contribute substantially to) mammalian aging. In
an extension of previously published accounts of RHH, I propose here that the lysosomal toxicity of oxidised cholesterol derivatives
(oxysterols) may contribute to the toxicity of mitochondrial mutations by affecting lysosomal function in many cell types
in the same way as they have been proposed to do in arterial macrophages. 相似文献
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125.
A. Grey A. Cooper C. McNeil S. O'Toole J. Thompson P. Grimison 《Internal medicine journal》2014,44(6):597-600
Vemurafenib is a tyrosine kinase inhibitor of BRAF that prolongs survival in patients with BRAF V600‐mutant metastatic melanoma. Secondary cutaneous malignancies are a well‐documented toxicity of vemurafenib, thought to be mediated by enhanced ERK signalling in BRAF wild‐type, RAS‐mutant cells. Vemurafenib could also promote growth of non‐cutaneous secondary malignancies by a similar mechanism. We present a case of an individual who received vemurafenib for metastatic melanoma and experienced rapid growth of a pre‐existing KRAS‐mutant pancreatic adenocarcinoma. 相似文献
126.
Ane Y Steffensen Mette Dandanell Lars J?nson Bent Ejlertsen Anne-Marie Gerdes Finn C Nielsen Thomas vO Hansen 《European journal of human genetics : EJHG》2014,22(12):1362-1368
Mutational screening of the breast cancer susceptibility gene BRCA1 leads to the identification of numerous pathogenic variants such as frameshift and nonsense variants, as well as large genomic rearrangements. The screening moreover identifies a large number of variants, for example, missense, silent, and intron variants, which are classified as variants of unknown clinical significance owing to the lack of causal evidence. Variants of unknown clinical significance can potentially have an impact on splicing and therefore functional examinations are warranted to classify whether these variants are pathogenic or benign. Here we validate a mini-gene splicing assay by comparing the results of 24 variants with previously published data from RT-PCR analysis on RNA from blood samples/lymphoblastoid cell lines. The analysis showed an overall concordance of 100%. In addition, we investigated 13 BRCA1 variants of unknown clinical significance or putative variants affecting splicing by in silico analysis and mini-gene splicing assay. Both the in silico analysis and mini-gene splicing assay classified six BRCA1 variants as pathogenic (c.80+1G>A, c.132C>T (p.=), c.213−1G>A, c.670+1delG, c.4185+1G>A, and c.5075−1G>C), whereas six BRCA1 variants were classified as neutral (c.-19-22_-19-21dupAT, c.302−15C>G, c.547+14delG, c.4676−20A>G, c.4987−21G>T, and c.5278−14C>G) and one BRCA1 variant remained unclassified (c.670+16G>A). In conclusion, our study emphasizes that in silico analysis and mini-gene splicing assays are important for the classification of variants, especially if no RNA is available from the patient. This knowledge is crucial for proper genetic counseling of patients and their family members. 相似文献
127.
In recent years, experience with transcatheter aortic valve implantation has led to improved outcomes in elderly patients with severe aortic stenosis (AS) who may not have previously been considered for intervention. These patients are often frail with significant comorbid conditions. 相似文献
128.
Finn AV Saeed O Virmani R 《Circulation research》2012,110(9):e64; author reply e65-e64; author reply e66
129.
130.
Grey A Bolland M Reid I 《Annals of internal medicine》2012,156(12):904; author reply 904-904; author reply 905