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排序方式: 共有804条查询结果,搜索用时 62 毫秒
71.
目的:探讨彩色多普勒超声联合钼靶在未扪及肿块乳腺癌中的临床诊断价值。方法:选取我院乳腺科收治的未扪及肿块乳腺癌患者92例,回顾性分析92例患者术前彩色多普勒超声和钼靶检查结果与手术病理相印证,对比不同的检查方法与病理诊断结果的符合率。结果:单纯彩色多普勒超声检查与单纯钼靶机检查诊断准确率无明显差异(P0.05),而彩色多普勒超声联合钼靶机检查诊断准确率明显高于单纯彩色多普勒超声检查诊断准确率和单纯钼靶机检查诊断准确率,差异有统计学意义(P0.05)。结论:彩色多普勒超声联合钼靶能够明显提高未扪及肿块乳腺癌诊断的准确率,对临床具有指导意义,值得临床推广。 相似文献
72.
《Animal : an international journal of animal bioscience》2015,9(6):919-927
In endangered and local pig breeds of small population sizes, production has to focus on alternative niche markets with an emphasis on specific product and meat quality traits to achieve economic competiveness. For designing breeding strategies on meat quality, an adequate performance testing scheme focussing on phenotyped selection candidates is required. For the endangered German pig breed ‘Bunte Bentheimer’ (BB), no breeding program has been designed until now, and no performance testing scheme has been implemented. For local breeds, mainly reared in small-scale production systems, a performance test based on in vivo indicator traits might be a promising alternative in order to increase genetic gain for meat quality traits. Hence, the main objective of this study was to design and evaluate breeding strategies for the improvement of meat quality within the BB breed using in vivo indicator traits and genetic markers. The in vivo indicator trait was backfat thickness measured by ultrasound (BFiv), and genetic markers were allele variants at the ryanodine receptor 1 (RYR1) locus. In total, 1116 records of production and meat quality traits were collected, including 613 in vivo ultrasound measurements and 713 carcass and meat quality records. Additionally, 700 pigs were genotyped at the RYR1 locus. Data were used (1) to estimate genetic (co)variance components for production and meat quality traits, (2) to estimate allele substitution effects at the RYR1 locus using a selective genotyping approach and (3) to evaluate breeding strategies on meat quality by combining results from quantitative-genetic and molecular-genetic approaches. Heritability for the production trait BFiv was 0.27, and 0.48 for backfat thickness measured on carcass. Estimated heritabilities for meat quality traits ranged from 0.14 for meat brightness to 0.78 for the intramuscular fat content (IMF). Genetic correlations between BFiv and IMF were higher than estimates based on carcass backfat measurements (0.39 v. 0.25). The presence of the unfavorable n allele was associated with increased electric conductivity, paler meat and higher drip loss. The allele substitution effect on IMF was unfavorable, indicating lower IMF when the n allele is present. A breeding strategy including the phenotype (BFiv) combined with genetic marker information at the RYR1 locus from the selection candidate, resulted in a 20% increase in accuracy and selection response when compared with a breeding strategy without genetic marker information. 相似文献
73.
74.
Shu‐Jyuan Yang Szu‐Min Chang Kun‐Che Tsai Wen‐Shiang Chen Feng‐Huei Lin Ming‐Jium Shieh 《The journal of gene medicine》2010,12(2):168-179
Background
Gene therapy has been used to treat a variety of health problems, but transfection inefficiency and the lack of safe vectors have limited clinical progress. Fabrication of a vector that is safe and has high transfection efficiency is crucial for the development of successful gene therapy. The present study aimed to synthesize chitosan‐alginate nanoparticles that can be used as carriers of the pAcGFP1‐C1 plasmid and to use these nanoparticles with an ultrasound protocol to achieve high efficiency gene transfection.Methods
Chitosan was complexed with alginate and the pAcGFP1‐C1 plasmid at different charge ratios to create chitosan‐alginate‐DNA nanoparticles (CADNs). The average particle size and loading efficiency were measured. Plasmid DNA retardation and integrity were analysed on 1% agarose gels. The effect of CADNs and ultrasound on the efficiency of transfection of cells and subcutaneous tumors was evaluated.Results
In the CADNs, the average size of incorporated plasmid DNA was 600–650 nm and the loading efficiency was greater than 90%. On the basis of the results of the plasmid DNA protection test, CADNs could protect the transgene from DNase I degradation. The transgene product expression could be enhanced efficiently if cells or tumor tissues were first given CADNs and then treated with ultrasound.Conclusions
The use of CADNs combined with an ultrasound regimen is a promising method for safe and effective gene therapy. Copyright © 2009 John Wiley & Sons, Ltd.75.
Maria E. Silva Serra Dina Murtinho Albertino Goth António M. D'A. Rocha Gonsalves Paulo E. Abreu Alberto A. C. C. Pais 《Chirality》2010,22(4):425-431
New chiral salen ligands were prepared by the ultrasound‐irradiated condensation of optically active (1R, 3S)‐1,2,2‐trimethyl‐1,3‐diaminocyclopentane with aromatic 1‐hydroxyaldehydes. The ultrasound‐mediated process is more convenient due to shorter reaction times, energy economy, and easier isolation of the products. The in situ formed Ti(IV)(salen) complexes, evaluated as catalysts in the enantioselective trimethylsilylcyanation of benzaldehyde, were found to be efficient for this process, originating the corresponding product in high yields (72–99%) and selectivities of up to 79%. The lowest energy transition states were determined by computational studies. These results were in qualitative agreement with the experimentally observed ones. Chirality, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
76.
Anne Sofie Busk Heitmann Ali Asghar Hakami Zanjani Martin Berg Klenow Anna Mularski Stine Lauritzen Snder Frederik Wendelboe Lund Theresa Louise Boye Catarina Dias Poul Martin Bendix Adam Cohen Simonsen Himanshu Khandelia Jesper Nylandsted 《The Journal of biological chemistry》2021,297(2)
Repair of damaged plasma membrane in eukaryotic cells is largely dependent on the binding of annexin repair proteins to phospholipids. Changing the biophysical properties of the plasma membrane may provide means to compromise annexin-mediated repair and sensitize cells to injury. Since, cancer cells experience heightened membrane stress and are more dependent on efficient plasma membrane repair, inhibiting repair may provide approaches to sensitize cancer cells to plasma membrane damage and cell death. Here, we show that derivatives of phenothiazines, which have widespread use in the fields of psychiatry and allergy treatment, strongly sensitize cancer cells to mechanical-, chemical-, and heat-induced injury by inhibiting annexin-mediated plasma membrane repair. Using a combination of cell biology, biophysics, and computer simulations, we show that trifluoperazine acts by thinning the membrane bilayer, making it more fragile and prone to ruptures. Secondly, it decreases annexin binding by compromising the lateral diffusion of phosphatidylserine, inhibiting the ability of annexins to curve and shape membranes, which is essential for their function in plasma membrane repair. Our results reveal a novel avenue to target cancer cells by compromising plasma membrane repair in combination with noninvasive approaches that induce membrane injuries. 相似文献
77.
Ralph E. Baddour Farhan N. Dadani Michael C. Kolios Stuart K. Bisland 《Journal of biological physics》2007,33(1):61-66
Ultrasound imaging is proving to be an important tool for medical diagnosis of dermatological disease. Backscatter spectral
profiles using high-frequency ultrasound (HFUS, 10–100 MHz) are sensitive to subtle changes in eukaryotic cellular morphology
and mechanical properties that are indicative of early apoptosis, the main type of cell death induced following photodynamic
therapy (PDT). We performed experiments to study whether HFUS could also be used to discern changes in bacteria following
PDT treatment. Pellets of planktonic Staphylococcus aureus were treated with different PDT protocols and subsequently interrogated with HFUS. Changes in ultrasound backscatter response
were found to correlate with antimicrobial effect. Despite their small size, distinct changes in bacterial morphology that
are indicative of cell damage or death are detectable by altered backscatter spectra from bacterial ensembles using HFUS.
This highlights the potential for HFUS in rapidly and non-invasively assessing the structural changes related to antimicrobial
response. 相似文献
78.
Diagnostic cardiac ultrasounds are an environment-friendly and non-ionising imaging technology. However, ultrasounds are not biologically inert, and their use might have profound clinical impact. This paper summarizes the known effects of cardiac ultrasound—compared to other major imaging techniques—to exposed patients and to clinically exposed physicians practising ultrasound imaging. Furthermore, this review also provides an overview of the evidences on the biological effects of diagnostic ultrasound—which suggest that ultrasound with frequency, intensity and duration fully in the diagnostic range have significant molecular, cellular and organ effects.
A better understanding of these effects may improve our understanding of the complex interactions between ultrasound and biological tissues and may open new avenues to therapeutic applications based on the ultrasound-modulated cell functions, such as membrane transduction, apoptosis, cell permeability and thrombolysis. 相似文献
79.
Kieler H 《Progress in biophysics and molecular biology》2007,93(1-3):301-308
A large number of foetuses are scanned on a routine basis and although it is generally assumed that prenatal ultrasound is safe; very few studies have in fact focused on possible adverse effects in humans. The epidemiological tools when studying possible adverse effects of prenatal ultrasound are randomised controlled trials and observational studies such as cohort and case–control studies. There are advantages and disadvantages with all study designs. In this review, some of the challenges that have to be met are discussed based on experiences from a randomised controlled trial, cohort studies and an ongoing case–control study. 相似文献
80.
Jensen JA 《Progress in biophysics and molecular biology》2007,93(1-3):153-165
The paper gives an introduction to current medical ultrasound imaging systems. The basics of anatomic and blood flow imaging are described. The properties of medical ultrasound and its focusing are described, and the various methods for two- and three-dimensional imaging of the human anatomy are shown. Systems using both linear and non-linear propagation of ultrasound are described. The blood velocity can also be non-invasively visualized using ultrasound and the basic signal processing for doing this is introduced. Examples for spectral velocity estimation, color flow imaging and the new vector velocity images are presented. 相似文献