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501.
Bruce N. Ames Lois Swirsky Gold 《Angewandte Chemie (International ed. in English)》1990,29(11):1197-1208
The public has numerous misconceptions about the relationship between environmental pollution and human cancer. Underlying these misconceptions is an erroneous belief that nature is benign. In this article we highlight eight of these misconceptions and describe the scientific information that undermines each one. 相似文献
502.
The objective of this study was to distinguish within a population of patients with and without breast cancer. The study was based on the University of Wisconsin's dataset of 569 patients, of whom 212 were subsequently found to have breast cancer. A subset-conjunctive model, which is related to Logical Analysis of Data, is described to distinguish between the two groups of patients based on the results of a non-invasive procedure called Fine Needle Aspiration, which is often used by physicians before deciding on the need for a biopsy. We formulate the problem of inferring subset-conjunctive rules as a 0-1 integer program, show that it is NP-Hard, and prove that it admits no polynomial-time constant-ratio approximation algorithm. We examine the performance of a randomized algorithm, and of randomization using LP rounding. In both cases, the expected performance ratio is arbitrarily bad. We use a deterministic greedy algorithm to identify a Pareto-efficient set of subset-conjunctive rules; describe how the rules change with a re-weighting of the type-I and type-II errors; how the best rule changes with the subset size; and how much of a tradeoff is required between the two types of error as one selects a more stringent or more lax classification rule. An important aspect of the analysis is that we find a sequence of closely related efficient rules, which can be readily used in a clinical setting because they are simple and have the same structure as the rules currently used in clinical diagnosis. 相似文献
503.
Hiroyuki Tsuda Katsumi Fukamachi Jiegou Xu Kazunori Sekine Shigetoshi Ohkubo Nobuo Takasuka Masaaki Iigo 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(7):208-215
Increasing attention is being paid to chemopreventive agents for individuals at high risk of cancer. We have concentrated on bovine lactoferrin (bLF), an 80 kDa iron-binding glycoprotein known to have anti-microbial and immunoprotective effects. Lactoferrin is particularly abundant in colostrum, and is also present in tears, saliva and seminal and uterine secretions. However, only little is known regarding its influence on carcinogenesis. We have shown preventive effects of bLF and its fragment peptide, lactoferricin (bLFcin), consisting of a 25 amino acid sequence without iron binding capacity, on chemically-induced colon carcinogenesis in the rat and transplanted carcinoma cell metastasis in the mouse. The mechanisms are wide-spectrum, including elevation of caspase-1 and IL-18 in the small intestine, enhancement of the cell killing activity of cytotoxic T and natural killer (NK) cells, and anti-inflammatory and anti-angiogenic effects. It also inhibits the induction of liver CYP1A2, a carcinogen activating enzyme, and induces apoptosis in the colon epithelium of carcinogen treated rats. Thus, bLF possesses multi-functional potential to suppress carcinogenesis and is a good candidate for practical application in humans. 相似文献
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506.
Zishan Feng Wei Zhang Longjie Li Bocheng Tu Weicong Ye Xiaofeng Tang Hongbo Wang Xianjin Xiao Tongbo Wu 《中国化学快报》2021,32(2):779-782
We presented a low-abundance mutation detection method with lambda exonuclease and DNA threeway junction structure.The assistant strand in the DNA three-way junction structure could regulate the reaction system from the kinetics and thermodyna mics aspects.The optimization of the assista nt strand helps to improve the selectivity of the mutant-type DNA to the wild-type DNA about 35 times.Moreover,the cost of the optimization process could be saved by about 90%.The method was applied to the detection of a human ovarian cancer-related gene mutation BRCA1(rs1799949,c.2082 CT).The limit of detection to the mutation abundance in the DNA three-way junction structure system(0.2%) was one order lower compared with that in the double-stranded DNA structure system(2%).The mutation abundance in different standard samples was quantitively measured,and the results were consistent with the initial abundance in the standard samples. 相似文献
507.
Srihari Pabbaraja Naresh Gantasala Sridhar Ydhyam Hari Krishna Namballa Subhashini Gundeboina Mallikharjuna R. Lambu Sanjeev Meena Dipak Datta 《Tetrahedron letters》2018,59(26):2570-2576
Stereoselective synthesis of twenty (three 12-, five 13- and twelve 14-membered) macrolides and seventeen functionalized 2,6-trans-disubstituted dihydropyran derivatives have been achieved. The key reactions include an Achmatowicz rearrangement, Ferrier-type alkynylation, Yamaguchi macrolactonization and Lindlar’s hydrogenation. Biological screening of the synthesised compounds showed moderate activity against human cancer cell-lines. 相似文献
508.
《中国化学快报》2020,31(7):1787-1791
About 90% cancer-related mortality results from the cancer metastasis, which generally undergoes after epithelial-mesenchymal transition (EMT) process. N-Cadherin, overexpressed on cancer cell surface during EMT, can enhance the migration of cancer cells. Herein, we design and synthesize a transformable peptide BP-KLVFF-SWTLYTPSGQSK (BFS) that can block N-cadherin for inhibiting cancer migration and metastasis. The peptide BFS consists of three modules including (1) the hydrophobic bis-pyrene (BP) unit for forming and locating nanoparticles, (2) the KLVFF peptide sequence for forming and stabilizing fibrous structures and (3) the targeting peptide sequence SWTLYTPSGQSK that can specifically bind to N-cadherin. The peptide BFS can form nanoparticles in PBS, which can transform to nanofibers when targeting and binding to N-cadherin. The nanofibers inhibit the migration of N-cadherin overexpressed MDA-MB-436 cancer cells. The peptide BFS shows 83.6% inhibiting rate in cells wound healing assay. In addition, the inhibition rate is 67.9% when the BFS applied in transwell migration assay. These results indicate that the BFS has excellent ability to inhibit migration of cancer cells. This self-assembly strategy could be potentially utilized to regulate the key protein during EMT for inhibiting the tumor metastasis. 相似文献
509.
In order to identify the signature genes of tumorigenesis, the pattern-recognition method was used to analyze the gene methylation (ME) data which included only normal and cancer samples and was collected from the TCGA (The Cancer Genome Atlas) database. Here, we analyzed the DNA methylation profiles of the six types of cancer and the ME signature genes for each cancer were selected by means of a combination of correlation, student's t-test and Elastic Net. Modeling by support vector machine, the accuracy of ME signature genes can be as high as 98 % for training set and as high as 97 % for the independent test set, the recognition accuracy of stage I is more than 97 % for training set and more than 98 % for test set. Then, the common signature genes and common pathways emerging in multiple cancers were obtained. A functional analysis of these signature genes indicates that the identified signatures have direct relationship with tumorigenesis and is very important for understanding the pathogenesis of cancer and the early therapy. 相似文献
510.
《中国化学快报》2020,31(6):1345-1356
Cancer is one of the diseases that have the highest mortality,which threatens the human health.Chemotherapy functions as the most widely used strategy in clinic to treat cancer,still exists urgent problems,like lacking selectivity and causing severe side effects.According to detailed researches on the metabolism,functions and histology of cancer tissues,many different features of cancer are uncovered,like lower pH in microenvironment,abnormal redox level in intracellular compartments and elevated expression level of several enzymes and receptors.Recently,the development of smart nanoparticles that response to tumor specific microenvironment has lighted up hope for selective cancer therapy.Herein,this review mainly focuses on pH-sensitive nano scale materials for anti-cancer drug delivery.We summarized the formation progress of acidic tumor microenvironment,the mechanism of pHresponsive drug delivery system and nanomaterials that responsive to acidic pH in tumor microenvironment. 相似文献