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排序方式: 共有549条查询结果,搜索用时 15 毫秒
1.
目的 探讨十二指肠肿瘤血流量存在的异质性及容积灌注CT成像对降低肿瘤异质性的影响。方法 纳入我院2013年1月至2014年11月十二指肠结节病例的132例,其中腺癌48例,间质瘤52例,淋巴瘤32例。所有的病例均行单层面灌注CT和容积灌注CT成像扫描,比较两者对十二指肠恶性肿瘤的诊断效能,采用变异系数评价两者在影像学异质性的差异,评价肿瘤影像学异质性对十二指肠恶性肿瘤的影响。结果 容积灌注CT成像与单层面灌注CT诊断恶性结节的效能其敏感性、特异性、准确性、阴性预测值、阳性预测值比较均无明显差别(P0.05);中高分化组及低分化组两个亚组的容积灌注CT成像的变异系数也均小于单层面灌注CT的变异系数,组间相比具有统计学差异(P0.05);血流量差异性的大小相比具有统计学差异(P0.05)。结论 容积灌注CT成像与单层面灌注CT检查在诊断效能上无明显差异,稳定性好,肿瘤影像学异质性对评价十二指肠肿瘤血流量有着一定影响,容积灌注CT成像能够降低肿瘤异质性的影响。 相似文献
2.
Inter-study differences: How should they influence the interpretation and analysis of results? 总被引:2,自引:0,他引:2
K R Bailey 《Statistics in medicine》1987,6(3):351-360
In determining the role inter-study variation should play in an overview analysis, it is important to consider three factors: which question one is trying to answer; the degree of similarity or dissimilarity of design, and the degree to which heterogeneity of outcomes can be explained. Three questions one might be interested in are: whether treatment can be effective in some circumstances; whether treatment is effective on average, and whether treatment was effective on average in the trials at hand. Under the assumption of no qualitative interaction, the answers to these questions coincide. The O-E analysis most directly answers the third question. Other analyses are suggested when the first question is of interest, using the aspirin post-MI studies as an example. 相似文献
3.
目的 建立分离肝癌细胞系MHCC97细胞中对罗丹明123染料具有不同排斥能力细胞亚群的方法,并探讨其在肝癌干细胞和异质性研究中的意义.方法 利用流式细胞分选术(FCM)并结合不同浓度的罗丹明123(Rho123)染料,分析和分选肝癌细胞系MHCC97细胞中具有不同染料排斥能力的肝癌细胞亚群,再通过细胞生长的测定、软琼脂克隆形成以及免疫组织化学检测和裸鼠成瘤实验等方法,以比较不同肝癌细胞亚群的差异.结果 根据不同染料排斥能力可以将肝癌细胞系MHCC97细胞分为Rholow和Rhohigh2个亚群,2个亚群在增殖能力、克隆形成率以及甲胎蛋白(AFP)和角蛋白-19(CK-19)表达以及裸鼠成瘤实验上差异有统计学意义,Rholow亚群具有干细胞特性.结论 罗丹明123结合FCM可以富集具有干细胞特性的Rholow亚群,同时为进一步揭示肝癌异质性机制奠定基础. 相似文献
4.
5.
人体肥大细胞的多态性已受到广泛关注,对于肥大细胞分型的研究已成为这一问题的关键。本实验研究了42例人大肠4种肥大细胞类群光镜特征,其中两种为作者的新近发现,暂命名为结缔组织肥大细胞-1(CTMC-1)和粘膜肥大细胞-1(MMC-1)。 相似文献
6.
7.
目的探讨应用异种(牛)脱细胞真皮基质修复膜修复喉部手术后黏膜缺损的I临床使用价值。方法对20例喉癌术后的黏膜缺损应用异种脱细胞真皮基质修复膜1期修复,其中声门区癌18例,其中T2NoMo8例,T3N1MO5例,T3N2MO4例,T4N2MO1例。声门上区癌2例,T3N1MO1例,T3N2MO1例。结果20例患者黏膜缺损修复均1期愈合。患者术后3-6个月应用电子喉镜复查,修复膜均已替代缺损黏膜组织,局部功能恢复;20例喉癌中6月生存率100%(11/11);一年生存率100%(3/3),其余9例术后不足6月,正在观察之中。讨论异种脱细胞基质修复膜为修复喉肿瘤术后的黏膜缺损提供了一种新的方法,手术操作简便,有很好的临床应用价值。 相似文献
8.
选用一组抗人白细胞表面分化抗原单克隆抗体和基因探针,依靠间接免疫荧光技术、Ap-AAP桥联酶标免疫组化染色和分子杂交手段.对111例急性T淋巴细胞白血病(T-ALL)进行了免疫分型研究。本研究所观察到的T-ALL细胞表型绝大多数反映着正常胸腺细胞分化发育阶段或某些少见类型细胞的表型特征,亦有少数病例则无正常淋巴细胞相对应的表型,表明T-ALL细胞的高度异质性。对T-ALL表型的研究为今后深入探讨胸腺内淋巴细胞的分化成熟以及T-ALL发生学提供了良好的研究模式。 相似文献
9.
Summary Blood flow heterogeneity in normal myocardium may be caused by heterogeneous metabolic demand. We studied, from 80 tissue samples of the left ventricle (LV) of eight anesthetised, open-chest dogs (with prior -blockade (metoprolol) in four dogs), the radioactivity of201Thalliumchloride (201Tl), an indicator of blood flow, and of the fatty acid131-Iodine-heptadecanoic acid (131I-HDA), an indicator of metabolic demand, 3 min after intravenous injection. Global LV uptake (in percent of injected dose ×10–2, per g tissue; mean ±SD) was 4.94±0.71 for201Tl and 4.48±0.58 for131I-HDA in the dogs without -blockade, and 2.08±0.26 and 1.69±0.20, respectively, in dogs with -blockade (p<0.05). Beta-blockade thus decreased the fraction of cardiac output delivered to the LV, concurrently with a decreased heart rate and arterial blood pressure (p<0.05) and, thus, global metabolic demand and fatty acid uptake. Regional radioactivities per gram were normalized for mean LV radioactivities and heterogeneity was expressed as the coefficient of variation (CV). For pooled data (n=320) in dogs without -blockade, regional201Tl and131I-HDA radioactivities varied from a factor of 0.1 to 1.6 and 0.3 to 1.8 of mean radioactivities, with a CV of 22.9 and 19.4%, respectively, and correlated (r=0.77, p<0.005). For pooled data (n=320) in dogs with -blockade, regional201Tl and131I-HDA radioactivities varied from a factor of 0.2 to 1.5 and 0.2 to 1.6 of mean radioactivity and CV was 23.6% and 24.8%, respectively: r=0.92 (p<0.005). The endo/epi ratio for both radioactivities exceeded unity in each dog. In normal myocardium, blood flow and fatty acid uptake are thus heterogeneous, both transmurally and circumferentially, and matched, concomitantly with coupling of global blood flow to global metabolic demand and fatty acid uptake. This supports the idea that heterogeneous myocardial O2 supply reflects heterogeneous metabolic demand. 相似文献
10.
In order to determine whether the growth of ras oncogene-transformed cells and nontransformed cells was inhibited differently by the chemotherapuetic drug cytosine arabinoside
(Ara-C) their growth was analyzed by a novel colony-based assay that is sensitive and appropriate for heterogeneous cell populations.
Colonies of nontransformed NIH3T3 cells, or ras onco- gene-transformed NIH(ras) cells, were grown in the absence of drug and then divided into subclones. Subclones were allowed to continue to grow in
the absence or presence of drug. Growth inhibition was determined by comparing the growth of drug-treated subclones with the
growth of related untreated subclones. Colonies of nontransformed cells grown in the absence of the drug displayed a large
variation in growth, and when grown in the presence of the drug displayed a large variation in growth inhibition. Colonies
of transformed cells also displayed a large variation in the absence and presence of the drug. For each cell line, related
subclones were more similar to each other than to unrelated subclones, implying inheritance of growth rates and drug response.
For NIH3T3 cells, the growth of subclones in the presence of drug was highly correlated with the growth of related subclones
in the absence of drug. However, for NIH3T3(ras) cells the growth of subclones in the presence of drug was not correlated with the growth of related subclones in the absence
of drug. Therefore, ras oncogene-transformed and nontransformed cell populations differ in their response to Ara-C.
Received: 3 November 1995/Accepted: 30 July 1996 相似文献