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排序方式: 共有173条查询结果,搜索用时 31 毫秒
1.
肺癌在中国恶性肿瘤的发病率位居第一,随着低剂量薄层CT在肺癌筛查中的广泛应用,临床发现更多表现为非完全实性结节的肺腺癌,目前众多研究使CT影像学特征和肺腺癌病理的关系得到更进一步的认知,虽然CT能对部分非完全实性结节做出定性和定位诊断,但仍有部分非完全实性结节诊断困难,PET-CT结合了病灶的代谢信息和精确的定位信息,从而提高对肺部结节诊断的敏感性、特异性、准确性,综合多个文献PET-CT在非完全实性结节中的诊断分期价值较CT无明显提升,却在评估预后和制定合适手术方案上可以起到一定的作用,本文就PET-CT在SSN中的应用价值进行阐述。 相似文献
2.
Glucose metabolism and insulin secretion were studied in isolated rat pancreatic islets of different sizes and the amount of tissue was quantitated by the measurement of DNA. It was found that larger islets (140-210 ng DNA/islet) utilized more glucose (based on the conversion of 3H-5-glucose to [3H]20) per ng of DNA than islets containing less DNA (60-120 ng/islet). However, the insulin secreted per ng of DNA in response to a given glucose concentration was the same in islets of all sizes. Also, the islet insulin and glucagon content when expressed in terms of DNA did not depend upon islet size. Thus, although glucose utilization rates expressed as a function of islet DNA content were greater in larger islets, no such relationship was found for glucose-induced insulin release or insulin and glucagon content. 相似文献
3.
G Scala G Caputo M Corona G Colella 《Bollettino della Società italiana di biologia sperimentale》1983,59(4):439-443
The structural and histological characteristics of the limiting layer between the cortex and medulla of the bursa of Fabricius in the duck are described in relation to different functional moments of the organ. On E.M. study the limiting layer, in duck having 30 days of age, is constituted of reticular-epithelial cells palisades in shape with many cytoplasmics extension. Lymphatic migration occur in interstitial spaces. 相似文献
4.
Chinese hamster V79 cells were mutagenized with ethyl methanesulfonate at various concentrations. Clones resistant to 8-azaguanine (20 and 80 micrograms/ml) or 6-thioguanine (4 micrograms/ml) were selected at different times after the treatments. The total yield of induced mutations was only slightly affected by the kind and concentration of purine analog used in the selection. However, full phenotypic expression of the mutants selected with 8-azaguanine was achieved earlier than that of mutants resistant to 6-thioguanine. This result seems to be best explained by the reported lower affinity of 8-azaguanine for the wild-type HGPRT enzyme, thus providing evidence that, in this gene-mutation assay, the phenotypic expression time has a physiological component. 相似文献
5.
P. M. Armenante L. S. Colella D. Kafkewitz M. J. Larkin 《Applied microbiology and biotechnology》1996,46(5-6):667-672
The adsorption of 4-chlorophenol (4-CP) on activated carbon was studied experimentally both in the presence and in the absence
of an inactivated anaerobic biofilm on the surface of carbon pellets. The presence of the biofilm markedly decreased the rate
of 4-CP adsorption. However, the final near-equilibrium state (at 27 h) was not affected, and the incremental amount of material
adsorbed on the pellets was similar both in the presence and in the absence of the biofilm. The biosorption of 4-CP by a biofilm
coating non-adsorbing pellets was also determined. It appears that the biofilm also has some adsorption capability. Freundlich-type
equations were used to correlate all data, and transient and near-equilibrium isotherms were obtained for 4-CP adsorption
on different adsorbing materials at different times.
Received: 30 April 1996 / Received revision: 17 July 1996 / Accepted: 4 August 1996 相似文献
6.
对κ-卡拉胶进行酸降解得到三种卡拉胶低聚糖,并进一步琥珀酰基化得到分子量分别为2720、4000和5960的κ-卡拉胶琥珀酰衍生物(A、B和C)。对产物进行FT-IR表征,并测得其琥珀酰基取代度(DS)分别为0.61、0.29和0.83。检测了三种κ-卡拉胶琥珀酰衍生物对超氧阴离子自由基O2.-、DPPH自由基、羟基自由基.OH以及过氧化氢的清除活性。结果表明:随着取代度的增加,其清除超氧阴离子自由基O2.-和DPPH自由基的能力增强;随着分子量的增加,其清除羟基自由基.OH和过氧化氢的能力增强。这可能与衍生物的羟基含量、取代基团的性质以及取代度等因素有关。 相似文献
7.
烟青虫感染核型多角体病毒后围食膜的病变 总被引:3,自引:1,他引:3
昆虫的围食膜是衬在昆虫中肠内一种网状的结构,它可充作虫体抵御外来病原侵染的一道屏障。关于鳞翅目昆虫幼虫感染了昆虫病毒后围食膜的病变问题,国内外鲜有报道。尤锡镇和康慧娟(1985)曾以实验证明家蚕围食膜对核型多角体病毒有灭活作用,而且认为核型多角体病毒不能侵染和破坏围食膜。Derksen和Granados(1988)则证明染病幼虫的围食膜因不同杆状病毒(包括两种核型多角体病 相似文献
8.
【目的】为了解析油菜种子硫代葡萄糖苷性状的重要遗传位点及候选基因,【方法】本研究利用KN DH群体在冬性环境2015-2018连续4年的种子硫苷含量表型和KN 高密度SNP遗传连锁图谱,通过Wincart 2.5软件的符合区间作图法对甘蓝型油菜种子硫代葡萄糖苷含量进行QTL定位和潜在候选基因鉴定。【结果】共鉴定到47个硫苷含量QTL,单个QTL解释表型变异最大是qGC.16YL19-4(19.44%),解释表型变异最小的是qGC.15YL12-5(1.82%)。利用元分析的方法将初步鉴定的47个QTL整合为38个consensus QTL,其中7个consensus QTL(cqGC.A9-5、cqGC.A9-7、cqGC.A9-9、cqGC.C2-9、cqGC.C2-10、cqGC.C9-5和cqGC.C9-6)为环境稳定表达QTL,包括3个硫苷含量主效QTL(cqGC.A9-5、cqGC.C2-10和cqGC.C9-5)。在主效QTLcqGC.A9-5和cqGC.C9-5鉴定到3个候选基因BnaA09g05480D,BnaC09g05620D和BnaC09g05810D,其功能主要涉及了油菜硫苷生物合成途径中吲哚-3-乙醛肟(IAOx)的合成和将2-烷基-苹果酸异构化形成3-烷基-苹果酸酯,以及硫苷的转运与分配。【结论】本研究获得了油菜种子硫苷含量3个主效QTL及3个候选基因,该结果为硫苷含量相关基因的功能机械和优质油菜品种培育提供理论依据。 相似文献
9.
Cathepsins L and B are lysosomal cysteine proteinases whose activities and cellular location are altered in many types of cancers and cancer cell lines. Cathepsins L and B play an unspecified role in cancer invasion and metastasis. The purpose of our study was to determine whether cathepsins L and B are important for the ability of two prostate cancer cell lines, PC3 and DU 145, to invade the basement membrane-like preparation, Matrigel®. Exposure of PC3 and DU145 to the irreversible cysteine proteinase inhibitor, E64, decreases the invasive ability of DU145, but not PC3. PC3 and DU145 were treated with the phorbol ester analogue, phorbol 12-myristate 13-acetate (PMA), a known tumor promoter that activates protein kinase C and contributes to the metastatic phenotype. PMA increased secreted cathepsin L+B activity and the invasive ability of PC3 and DU145; co-exposure to E64 and PMA decreased both cathepsin L+B activity and invasion. We conclude that DU145 requires cathepsin L+B activity more than PC3 for the invasion of the Matrigel®. When the amount of secreted cathepsin L+B activity is increased by PMA treatment, however, PC3 becomes dependent on cathepsin L+B for invasion. Our study demonstrates that modulation of the amount of secreted cathepsin L+B activity influences the invasive phenotype of PC3 and DU145. 相似文献
10.
Annamaria Tonazzi Cristina Mantovani Matilde Colella Giorgio Terenghi Cesare Indiveri 《Neurochemical research》2013,38(12):2535-2541
The carnitine/acylcarnitine transporter is a transport system whose function is essential for the mitochondrial β-oxidation of fatty acids. Here, the presence of carnitine/acylcarnitine carrier (CACT) in nervous tissue and its sub-cellular localization in dorsal root ganglia (DRG) neurons have been investigated. Western blot analysis using a polyclonal anti-CACT antibody produced in our laboratory revealed the presence of CACT in all the nervous tissue extracts analyzed. Confocal microscopy experiments performed on fixed and permeabilized DRG neurons co-stained with the anti-CACT antibody and the mitochondrial marker MitoTracker Red clearly showed a mitochondrial localization for the carnitine/acylcarnitine transporter. The transport activity of CACT from DRG extracts reconstituted into liposomes was about 50 % in respect to liver extracts. The experimental data here reported represent the first direct evidence of the expression of the carnitine/acylcarnitine transporter in sensory neurons, thus supporting the existence of the β-oxidation pathway in these cells. 相似文献