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1.
目的:探讨MR弥散加权成像(DWI)鉴别诊断良恶性椎体压缩性骨折的临床价值。方法:对57例经临床或病理证实的椎体良恶性压缩性骨折患者行矢状位T1M、T2WI、T2WI/FS及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR序列和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数(ADC)值,并进行统计学分析。结果:(1)MR常规序列和DWI序列(b=500s/mm2)表现:良性椎体压缩性骨折呈长T1长或等T2改变,T2WI/FS呈高信号,DWI可以呈高信号、等信号及低信号;恶性椎体压缩性骨折呈长T1长T2信号,大部分病灶T2WUFS及DWI呈高信号,少数变现为低信号;(2)MR常规序列和DWI序列(b=500s/mm2)病灶检出率的比较:T1WI、T2WI/FS及DWI序列病灶检出率均高于T2WI序列,其间的差别有显著性意义(P〈0.01),T1WI、T2WI/FS及DWI序列病灶检出率之间无显著性差异(P〉0.01);(3)ADC值比较:在DWI(b=500s/mm2)上,良性组ADC值为(2.03±0.83)×10^3mm^2/s,恶性组ADC值为(1.37±0.75)×10^-3mm^2/s,正常组ADC值为(0.36±0.21)×10^-3mm^2/s,成像条件相同时,良性组高于恶性组,两组间有明显的统计学意义(P〈0.05)。结论:DWI可较好的反映椎体的弥散特征,ADC值作为量化指标可对良恶性椎体压缩性骨折进行可靠鉴别。 相似文献
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辽宁是东北林蛙Rana dybowskii主要分布地之一,种群数量巨大,其群体遗传多样性有待评估.本研究应用ISSR标记技术对东北林蛙4个种群105个样本进行研究,5个引物共获得44条清晰谱带,4个种群的多态位点率均大于75%,Nei's基因多样性为0.2851,Shannon信息指数为0.4476,显示了较高的遗传多样性.对遗传分化系数、Nei's遗传距离、AMOVA分子变异巢式方差分析和F-统计量等遗传参数的统计结果表明,辽宁东北林蛙种群间已经出现一定程度的遗传分化,分析认为,自然屏障(高山和平原等)以及栖息地片段化是其遗传分化形成的主要因素. 相似文献
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Proteins in the seminal fluid of animals with internal fertilization effect numerous responses in mated females that impact both male and female fertility. Among these proteins is the highly represented class of proteolysis regulators (proteases and their inhibitors). Though proteolysis regulators have now been identified in the seminal fluid of all animals in which proteomic studies of the seminal fluid have been conducted (as well as several other species in which they have not), a unified understanding of the importance of proteolysis to male fertilization success and other reproductive processes has not yet been achieved. In this review, we provide an overview of the identification of proteolysis regulators in the seminal fluid of humans and Drosophila melanogaster, the two species with the most comprehensively known seminal fluid proteomes. We also highlight reports demonstrating the functional significance of specific proteolysis regulators in reproductive and post‐mating processes. Finally, we make broad suggestions for the direction of future research into the roles of both active seminal fluid proteolysis regulators and their inactive homologs, another significant class of seminal fluid proteins. We hope that this review aids researchers in pursuing a coordinated study of the functional significance of proteolysis regulators in semen. Mol. Reprod. Dev. © 2012 Wiley Periodicals, Inc. 相似文献
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Larson Boundenga Boris Makanga Benjamin Ollomo Aude Gilabert Virginie Rougeron Bertrand Mve-Ondo Céline Arnathau Patrick Durand Nancy Diamella Moukodoum Alain-Prince Okouga Lucresse Delicat-Loembet Lauriane Yacka-Mouele Nil Rahola Eric Leroy Cheikh Tidiane BA Francois Renaud Franck Prugnolle Christophe Paupy 《PloS one》2016,11(2)
Re-examination, using molecular tools, of the diversity of haemosporidian parasites (among which the agents of human malaria are the best known) has generally led to rearrangements of traditional classifications. In this study, we explored the diversity of haemosporidian parasites infecting vertebrate species (particularly mammals, birds and reptiles) living in the forests of Gabon (Central Africa), by analyzing a collection of 492 bushmeat samples. We found that samples from five mammalian species (four duiker and one pangolin species), one bird and one turtle species were infected by haemosporidian parasites. In duikers (from which most of the infected specimens were obtained), we demonstrated the existence of at least two distinct parasite lineages related to Polychromophilus species (i.e., bat haemosporidian parasites) and to sauropsid Plasmodium (from birds and lizards). Molecular screening of sylvatic mosquitoes captured during a longitudinal survey revealed the presence of these haemosporidian parasite lineages also in several Anopheles species, suggesting a potential role in their transmission. Our results show that, differently from what was previously thought, several independent clades of haemosporidian parasites (family Plasmodiidae) infect mammals and are transmitted by anopheline mosquitoes. 相似文献
6.
Relvas JB Setzu A Baron W Buttery PC LaFlamme SE Franklin RJ ffrench-Constant C 《Current biology : CB》2001,11(13):1039-1043
Myelination represents a remarkable example of cell specialization and cell-cell interaction in development. During this process, axons are wrapped by concentric layers of cell membrane derived either from central nervous system (CNS) oligodendrocytes or peripheral nervous system Schwann cells. In the CNS, oligodendrocytes elaborate a membranous extension with an area of more than 1000 times that of the cell body. The mechanisms regulating this change in cell shape remain poorly understood. Signaling mechanisms regulated by cell surface adhesion receptors of the integrin family represent likely candidates. Integrins link the extracellular environment of the cell with both intracellular signaling molecules and the cytoskeleton and have been shown to regulate the activity of GTPases implicated in the control of cell shape. Our previous work has established that oligodendrocytes and their precursors express a limited repertoire of integrins. One of these, the alpha6beta1 laminin receptor, can interact with laminin-2 substrates to enhance oligodendrocyte myelin membrane formation in cell culture. However, these experiments do not address the important question of integrin function during myelination in vivo, nor do they define the respective roles of the alpha and beta subunits in the signaling pathways involved. Here, we use a dominant-negative approach to provide, for the first time, evidence that beta1 integrin function is required for myelination in vivo and use chimeric integrins to dissect apart the roles of the extracellular and cytoplasmic domains of the alpha6 subunit in the signaling pathways of myelination. 相似文献
7.
Elliott RL Oliver RM LaFlamme JA Gillaspy ML Hammond M Hank RF Maurer TS Baker DL DaSilva-Jardine PA Stevenson RW Mack CM Cassella JV 《Bioorganic & medicinal chemistry letters》2003,13(20):3593-3596
A series of 2-heteroaryl-4-arylimidazoles with potent in vitro activity at the NPY5 receptor was developed. Introduction of electron-withdrawing groups on the 4-aryl ring led to a significant improvement of in vitro potency. Several analogues from this series had anorectic activity in rodent feeding models, but were also found to have undesired behavioral effects in spontaneous locomotor activity. 相似文献
8.
Claudia G Petersen Fabiana C Massaro Ana L Mauri Joao BA Oliveira Ricardo LR Baruffi Jose G FrancoJr 《Reproductive biology and endocrinology : RB&E》2010,8(1):149
Background
The present study aimed to evaluate the efficacy of the hyaluronic acid (HA) binding assay in the selection of motile spermatozoa with normal morphology at high magnification (8400x). 相似文献9.
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Data for the historical years 1970 and 1995 and the FAO-Agriculture Towards 2030 projection are used to calculate N inputs (N fertilizer, animal manure, biological N fixation and atmospheric deposition) and the N export from the field in harvested crops and grass and grass consumption by grazing animals. In most industrialized countries we see a gradual increase of the overall N recovery of the intensive agricultural production systems over the whole 1970-2030 period. In contrast, low N input systems in many developing countries sustained low crop yields for many years but at the cost of soil fertility by depleting soil nutrient pools. In most developing countries the N recovery will increase in the coming decades by increasing efficiencies of N use in both crop and livestock production systems. The surface balance surplus of N is lost from the agricultural system via different pathways, including NH3 volatilization, denitrification, N2O and NO emissions, and nitrate leaching from the root zone. Global NH3-N emissions from fertilizer and animal manure application and stored manure increased from 18 to 34 Tg·yr-1 between 1970 and 1995, and will further increase to 44 Tg·yr-1 in 2030. Similar developments are seen for N2O-N (2.0 Tg·yr-1 in 1970, 2.7 Tg·yr-1 in 1995 and 3.5 Tg·yr-1 in 2030) and NO-N emissions (1.1 Tg·yr-1 in 1970, 1.5Tg·yr-1 in 1995 and 2.0 Tg·yr-1 in 2030). 相似文献