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711.
By combining two strands of pseudo-complementary peptide nucleic acid (pcPNA) with S1 nuclease, a tool for site-selective and dual-strand scission of DNA/RNA hybrids has been developed. Both of the DNA and the RNA strands in the hybrids are hydrolyzed at desired sites to provide unique sticky ends. The scission fragments are directly ligated with other DNA/RNA hybrids by using T4 DNA ligase, resulting in the formation of desired recombinant DNA/RNA hybrids. 相似文献
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Recent circulating tumor DNA (ctDNA) research has demonstrated its potential as a non-invasive biomarker for cancer. However, the deployment of ctDNA assays in routine clinical practice remains challenging owing to variability in analytical approaches and the assessment of clinical significance. A well-developed, analytically valid ctDNA assay is a prerequisite for integrating ctDNA into cancer management, and an appropriate analytical technology is crucial for the development of a ctDNA assay. Other determinants including pre-analytical procedures, test validation, internal quality control (IQC), and continual proficiency testing (PT) are also important for the accuracy of ctDNA assays. In the present review, we will focus on the most widely used ctDNA detection technologies and the key quality management measures used to assure the accuracy of ctDNA assays. The aim of this review is to provide useful information for technology selection during ctDNA assay development and assure a reliable test result in clinical practice. 相似文献
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M.C. Lang G. de Murcia A. Mazen R.P.P. Fuchs M. Leng M. Daune 《Chemico-biological interactions》1982,41(1):83-93
The influence of chromatin structure on the accessibility of DNA to the model ultimate carcinogen N-acetoxy-N-2-acetylaminofluorene (N-Aco-AAF) was investigated by means of an immunoelectron microscopic technique developed recently. An homogeneous population of core particles or trinucleosomes from chicken erythrocytes, was submitted to electrophilic attack by N-Aco-AAF. After DNA isolation, N-2-acetylaminofluorene (AAF) binding sites were mapped upon the DNA fragments using specific antibodies as a probe. Our results indicate a non-random binding of AAF along the DNA. Our data support the results of previous studies showing a preferential binding on the linker region. 相似文献
717.
Coral García-Pastor Rafael Blázquez-Serra Ricardo J. Bosch Francisco J. Lucio Cazaña Ana B. Fernández-Martínez 《生物化学与生物物理学报:疾病的分子基础》2019,1865(9):2504-2515
The therapeutic efficacy of the antineoplastic drug cisplatin is limited by its nephrotoxicity, which affects particularly to proximal tubular cells (PTC). Cisplatin-induced cytotoxicity appears to be multifactorial and involves inflammation, oxidative stress as well as apoptosis. We have recently shown that the cyclo-oxygenase-2 (COX-2)/intracellular prostaglandin E2 (iPGE2)/EP receptor pathway mediates the apoptotic effect of cisplatin on human proximal tubular HK-2 cells. Here, we studied the effects on HK-2 cells of apoptotic bodies (ABs) generated after treatment of HK-2 cells with cisplatin. We found that ABs inhibited cell growth, induced apoptosis and increased COX-2 expression and iPGE2 in ABs-recipient HK-2 cells. Inhibition of the COX-2/iPGE2/EP receptor pathway in these cells prevented the effects of ABs without interfering with their internalization. Interestingly, 2nd generation ABs (i.e. ABs released by cells undergoing apoptosis upon treatment with ABs) did not trigger apoptosis in naïve HK-2 cells, and stimulated cell proliferation through the COX-2/iPGE2/EP receptor pathway. These results suggest that ABs, through iPGE2-dependent mechanisms, might have a relevant role in the natural history of cisplatin-induced acute kidney failure because they contribute first to the propagation of the noxious effects of cisplatin to non-injured PTC and then to the promotion of the proliferative tubular response required for proximal tubule repair. Since iPGE2 also mediates both cisplatin-induced HK-2 cell apoptosis, intervention in the COX-2/iPGE2/EP receptor pathway might provide us with new therapeutic avenues in patients with cisplatin-induced acute kidney injury. 相似文献
718.
Lanhong Zheng Xiukun Lin Ning Wu Ming Liu Yuan Zheng Jun Sheng Xiaofeng Ji Mi Sun 《生物化学与生物物理学报:癌评论》2013
Apoptosis is a critical defense mechanism against the formation and progression of cancer and exhibits distinct morphological and biochemical traits. Targeting apoptotic pathways becomes an intriguing strategy for the development of chemotherapeutic agents. Peptides from marine organisms have become important sources in the discovery of antitumor drugs, especially when modern technology makes it more and more feasible to collect organisms from seas. This primer summarizes several marine peptides, based on their effects on apoptotic signaling pathways, although most of these peptides have not yet been studied in depth for their mechanisms of action. Novel peptides that induce an apoptosis signal pathway are presented in association with their pharmacological properties. 相似文献
719.
Markers of apoptosis were followed in batch hybridoma cultures carried out in protein-free medium. Samples were collected
on day 0, representing early exponential phase (viability 91%), and on day 8, corresponding to late stationary phase (viability
8%). The apoptotic index reflecting the relative number of bodies insoluble in 6 M guanidinium hydrochloride in the culture
of day 8 (30%) exceeded markedly the index in the culture of day 0 (2.5%). A gel chromatography on Sepharose 2B was developed
for quantitative evaluation of fragmented cellular DNA. This analysis, including a correction for nonspecific fragmentation,
showed that on day 8 more than 30% of cellular DNA was fragmented, whereas on day 0 it was less than 5%. Control necrotic
cells prepared by rapid killing in 1% sodium azide displayed a low apoptotic index (2.4%) and low DNA fragmentation. Electrophoretic
patterns in agarose gel showed a typical “ladder” of fragments in the DNA sample of day 8. The demonstration of fragmented
cellular DNA and of the high incidence of apoptotic bodies at late stationary phase adds substantial weight to the view that
in hybridoma cultures apoptosis represents the prevalent mode of cell death. 相似文献
720.