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排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
重组合异种骨(RHB)骨形成蛋白(BMD)与去除抗原特性后的异种松质骨的复合物,是近年来医学研究的一个新成果。既具有BMP的高度诱导成骨作用,又具有松质骨的支架作用,十分便于临床使用、填充骨缺损。作者等应用RHB治疗16例骨缺损及骨不连,证实它是一种高效的成骨诱导物质,诱导生骨作用肯定,无明显副作用,临床使用方便,较自体骨移植愈合时间快,避免了取自体髂骨的痛苦。作者等认为,本生物制品颇值得大力推广应用。 相似文献
2.
同种与异种骨基质明胶修复颅骨缺损的实验研究 总被引:6,自引:1,他引:6
以家兔颅顶骨直径10mm园形骨缺损作为动物模型,分别植入同种(兔)、异种(人、猪、羊)的骨基质明胶。植入后4、8、12、16w进行x线摄片和组织学检查。结果显示,同种骨基质明胶无免疫排斥反应,具有良好的骨诱导作用,术后12w骨缺损完全修复;异种骨基质明胶植入早期,存在着不同程度的排斥反应,植骨后期(12~16w),随着排斥反应的减轻,亦出现了诱导成骨。结果说明,如能改进异种骨基质明胶的制作方法,降低其抗原性,将具有重要的临床应用价值。 相似文献
3.
我院基于XML异构数据集成的开发应用及研究 总被引:1,自引:0,他引:1
基于XML的数据集成,Web Services中间件能够较容易地实现对各数据源的描述以及数据源之间的数据转换,它在应用程序和数据库之间起着接口的作用.本文结合实际医院信息工作,运用VFP9 COM模型,作了有效性的研究及应用,并对标准数据集的二次开发进行了讨论。结果表明,该方法用于医院跨网络平台、跨应用系统、异构信息集成是有效的和易于操作的。 相似文献
4.
Eighteen cases of sarcomas of the breast are reported. Cases could be divided into two groups histogenetically. Group A, malignant cystosarcoma phylloides (14 cases); and Group B, pure sarcomas (4 cases). The malignant cystosarcoma phylloides occurred in the forth decade, had linger duration of illness invariably followed by sudden increase in the size of the tumor, had a striking mucoid and slimy look grossly, and showed discernible epithelial elements histologically. In the event of their recurrence the ductal elements were not seen microscopically. Contrarily, Group B cases presented in the sixth decade were rapidly growing from the beginning, and grossly were fleshy and haemorrhagic. Microscopically these did not reveal any epithelial component. There was poor correlation between cytologic malignancy and the biologic behavior in Group A. Mode of treatment seems more important in determining the subsequent course of the disease. Simple mastectomy with follow-up appears to be adequate in the majority of cases. 相似文献
5.
Xin Hu Shuangying Jiang Feifei Xu Cheng Zeng Xiangxiang Wang Wei Liu Aimin Cheng Chengying Ma Ning Gao Yuyu Zhao Junbiao Dai Guanghou Zhao 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(6)
Emerging evidence reveals that ribosomes are not monolithic but dynamic machines with heterogeneous protein compositions that can reshape ribosomal translational abilities and cellular adaptation to environmental changes. Duplications of ribosomal protein (RP) genes are ubiquitous among organisms and are believed to affect cell function through paralog-specific regulation (e.g., by generating heterogeneous ribosomes) and/or gene dose amplification. However, direct evaluations of their impacts on cell function remain elusive due to the highly heterogeneous cellular RP pool. Here, we engineered a yeast with homogeneous 40S RP paralog compositions, designated homo-40S, by deleting the entire set of alternative duplicated genes encoding yeast 40S RP paralogs. Homo-40S displayed mild growth defects along with high sensitivity to the translation inhibitor paromomycin and a significantly increased stop codon readthrough. Moreover, doubling of the remaining RP paralogous genes in homo-40S rescued these phenotypes markedly, although not fully, compared to the wild-type phenotype, indicating that the dose of 40S RP genes together with the heterogeneity of the contents was vital for maintaining normal translational functionalities and growth robustness. Additional experiments revealed that homo-40S improved paromomycin tolerance via acquisition of bypass mutations or evolved to be diploid to generate fast-growing derivatives, highlighting the mutational robustness of engineered yeast to accommodate environmental and genetic changes. In summary, our work demonstrated that duplicated RP paralogs impart robustness and phenotypic plasticity through both gene dose amplification and paralog-specific regulation, paving the way for the direct study of ribosome biology through monotypic ribosomes with a homogeneous composition of specific RP paralogs.Eukaryotic ribosomes are highly complex protein synthesis machinery composed of the small/40S subunit and the large/60S subunit. Historically, the ribosome was considered to be an invariant effector rather than a regulatory participant in translation. However, emerging studies have revealed heterogeneity among ribosomes, characterized by variable ribosomal protein (RP) contents and consequent specialization of the translational program for modulating growth robustness and stress response (1–4). Such findings led to the formulation of the concept of “specialized ribosomes”, wherein multiple populations of ribosomes with diverse compositions were produced, and each was tailored to carry different translational abilities, such as mRNA selectivity during translation as well as translation fidelity and elongation speed (5–7). Although current evidence proves the existence of ribosome heterogeneity and the functional specialization for distinct ribosomes in selectively translating specific subsets of messenger RNAs (mRNAs), the sources of ribosome heterogeneity and thereafter the output remain largely unknown and are subjects of great interest (5–7).In both lower and higher eukaryotes, many RPs are encoded by paralogous genes, possibly originating from genome duplication early in evolution and maintained afterward (7–9). For example, 24 of the 33 RPs in the yeast 40S ribosome subunit, which contains the ribosome decoding center, exist as paralog pairs, which allows 224 (>107) potential RP combinations by numbers alone. To date, numerous studies have examined the roles of individual RP paralogs in diverse organisms (e.g., yeast, amoebas, flies, and vertebrates), and, accordingly, rapidly growing evidence has shown that RP paralog pairs usually possess distinct or even opposite expression patterns and paralog-specific functions (10–12). Thus, heterogeneous RP paralogs not only regulate cell function by complementing each other’s expression levels (dose amplification) but also offer the potential to generate heterogeneous ribosomes by swapping distinct RP isoforms to fine-tune the translational program (paralog-specific regulation) (2, 10–12). However, direct evaluation of their effects on cell function, especially the functionalities of ribosomes, was obscured by the highly diversified cellular RP pool (5, 6).In this study, we homogenized the cellular 40S RP pool by removing one set of paralogous genes and consequently constructed a “designer” yeast named homo-40S. Although the successful engineering of homo-40S demonstrated that the presence of duplicated RP paralogs was not essential for yeast survival, our results showed that loss of RP paralogs in homo-40S led to decreased fitness and increased susceptibility to the translation error-inducing inhibitor paromomycin, which is indicative of altered translational activity and fidelity. Moreover, these phenotypes could be recovered markedly, although not fully, by doubling the RP paralogous genes in homo-40S. Furthermore, our study showed that homo-40S was able to improve paromomycin tolerance via acquisition of bypass mutations or evolved to be diploid to acquire fast-growing derivatives. Together, our work provides a strategy to acquire monotypic ribosomes with homogenized RP contents and experimentally demonstrates the functional significance for maintaining duplicated RP genes. 相似文献
6.
背景:人脐带间充质干细胞因其来源丰富,具有较强增殖分化能力,不涉及伦理道德问题,有望成为组织修复与再生工程的首选细胞。但是,对人脐带间充质干细胞异种静脉移植的安全性研究较少。
目的:观察Wistar大鼠静脉输注人脐带间充质干细胞后的安全性。
方法:SPF级Wistar大鼠30只,随机分为空白对照组、阴性对照组、细胞移植组,每组10只,雌雄各半。体外分离扩增人脐带间充质干细胞,细胞移植组大鼠尾静脉一次注射5×106间充质干细胞,注射体积为1 mL;阴性对照组大鼠尾静脉一次注射相同体积50 g/L葡萄糖注射液。注射后每天观察大鼠一般症状,14 d后解剖动物,进行血常规、血生化和脏器病理学检查及脏器质量测定。
结果与结论:细胞移植组大鼠血常规、血生化与对照组比较差异无显著性意义(P > 0.05)。细胞移植组大鼠脏器组织病理学观察与对照组大鼠无明显光镜下形态学差别。结果提示Wistar大鼠一次性静脉移植人脐带间充质干细胞是安全可行的,人脐带间充质干细胞异种移植对受者无不良影响。 相似文献
7.
Bruno Mattia Bizzarri Angelica Fanelli Lorenzo Botta Claudio Zippilli Silvia Cesarini Raffaele Saladino 《Materials》2021,14(18)
Dendrimers are highly branched structures with a defined shape, dimension, and molecular weight. They consist of three major components: the central core, branches, and terminal groups. In recent years, dendrimers have received great attention in medicinal chemistry, diagnostic field, science of materials, electrochemistry, and catalysis. In addition, they are largely applied for the functionalization of biocompatible semiconductors, in gene transfection processes, as well as in the preparation of nano-devices, including heterogeneous catalysts. Here, we describe recent advances in the design and application of dendrimers in catalytic organic and inorganic processes, sustainable and low environmental impact, photosensitive materials, nano-delivery systems, and antiviral agents’ dendrimers. 相似文献
8.
Andrew G. Lee Jonathan D. Shader Aroucha Vickers Orlando M. Diaz Jurij R. Bilyk 《Survey of ophthalmology》2019,64(2):248-253
An 82-year-old woman presented with right-sided proptosis, chemosis, and a supraorbital bruit. A dural carotid-cavernous fistula was suspected, but catheter angiography revealed an intraorbital inferior ophthalmic vein arteriovenous fistula supplied by the right ophthalmic artery and infraorbital branch of the internal maxillary artery. A primary orbital arteriovenous fistula can mimic the clinical and radiographic features of the more common carotid-cavernous fistula. 相似文献
9.
目的 :探讨HLA不全相合无血缘供者脐血移植 (UCBT)治疗血液系统恶性肿瘤造血重建、移植相关并发症的发生和生存情况。方法 :对 1例 15岁女性急性非淋巴细胞白血病 (ANLL)患者进行HLA 1个位点不相合2份UCBT。预处理方案 :采用白消安、环磷酰胺 (BU/CTX)方案 ,同时应用抗胸腺细胞球蛋白 (ATG)和Daclizumab(赛尼哌 ,zenapax)。移植物抗宿主病 (GVHD)的预防采用环孢菌素A(CsA)联合短程甲氨蝶呤 (MTX)和霉酚酸酯(MMF)方案。移植有核细胞数 (NC)为 4 .9× 10 7/kg ,CD34+ 细胞为 5 .36× 10 5/kg。结果 :中性粒细胞绝对计数 >0 .5× 10 9/L的时间为移植后第 15天 ;血小板计数 >5 0× 10 9/L的时间为移植后第 37天 ;全血细胞恢复正常的时间为移植后第 4 2天。移植后第 2 1天DNA指纹图提示供者型。受者已无病生存 2 0 0d。结论 :HLA 1个位点不相合的UCBT是可行的 ,对于体重量大的受者 2份脐血移植 (CBT)是可行的。 相似文献
10.
目的探讨HLA不全相合非亲缘供者脐血移植(UCBT)治疗儿童急性淋巴细胞白血病及其移植相关并发症.方法 1例急性淋巴细胞白血病(ALL)患儿进行HLA1个位点不合非亲缘供者的UCBT.预处理方案:氟达拉滨(Fludarabine)30 mg·kg-1·d-1×5d,环磷酰胺(CTX)60 mg·kg-1·d-1×2d,马利兰4mg·kg-1·d-1, 抗胸腺球蛋白(ATG兔抗)3mg·kg-1·d-1×3d.移植物抗宿主病(GVHD)的预防采用环胞菌素(CsA)加用骁悉(MMF)和甲基强的松龙方案.移植有核细胞数5.24×107/kg,CD34 细胞2.93×105/kg,CFU-GM0.93×105/kg.观察监测巨细胞病毒(CMV)感染,更昔洛韦(GCV)与磷甲酸钠联合应用.结果移植后28d造血重建,移植后84d血型转为供者型(B型),染色体检测转为供者46XX,移植后第22d出现Ⅱ度急性GVHD.移植后第22d DNA指纹图提示供者型.结论 UCBT造血重建快而稳定,移植相关并发症较少,急性GVHD严重程度较轻.HLA1个位点不合非亲缘供者的UCBT有效可行. 相似文献