排序方式: 共有58条查询结果,搜索用时 15 毫秒
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老龄化的社会、不断发展的延长生命的医疗干预、老年医保政策和个体决策的伦理,共同造就了美国日益严重的社会紧张:一方面要控制医保费用,一方面又要促进健康消费者使用生命维持技术。这些制造长寿的活动,就像许多其他的社会医疗实践一样,构成了生命管理以及新的伦理态度和社会参与的一个场所。这些活动——包括处理风险的必要性、对于循证干预的难以言"不"以及在临床条件下做出选择的义务——也处于卫生资源配给和改革的论争中心。心脏手术、器官移植和癌症治疗是三个延长生命的医学成功的范例,同时也是产生存在困境和社会困境之标志。医学人类学的视角彰显了生命制造与医疗支出之关联,也揭示了基于年龄配给医疗资源的持续的讨论。 相似文献
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Evolution of genes and genomes on the Drosophila phylogeny 总被引:2,自引:0,他引:2
Drosophila Genomes Consortium Clark AG Eisen MB Smith DR Bergman CM Oliver B Markow TA Kaufman TC Kellis M Gelbart W Iyer VN Pollard DA Sackton TB Larracuente AM Singh ND Abad JP Abt DN Adryan B Aguade M Akashi H Anderson WW Aquadro CF Ardell DH Arguello R Artieri CG Barbash DA Barker D Barsanti P Batterham P Batzoglou S Begun D Bhutkar A Blanco E Bosak SA Bradley RK Brand AD Brent MR Brooks AN Brown RH Butlin RK Caggese C Calvi BR Bernardo de Carvalho A Caspi A Castrezana S Celniker SE 《Nature》2007,450(7167):203-218
Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species. 相似文献
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Induction of monozygotic twinning in the mouse 总被引:1,自引:0,他引:1
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L. D. Jones W. R. Kaufman P. A. Nuttall 《Cellular and molecular life sciences : CMLS》1992,48(8):779-782
A tick vector of Thogoto (THO) virus was shown to secrete a factor in saliva which potentiates the transmission of THO virus to uninfected ticks feeding on an apparently non-viraemic host. The effect of the saliva activated transmission (SAT) factor on the virus occurred at the site of inoculation in the skin and was apparent even when the virus was introduced 3 days after the SAT factor. The results suggest that tick saliva can play an important role in disease transmission by virtue of host modification at the site of feeding. 相似文献
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Churchland MM Cunningham JP Kaufman MT Foster JD Nuyujukian P Ryu SI Shenoy KV 《Nature》2012,487(7405):51-56
Most theories of motor cortex have assumed that neural activity represents movement parameters. This view derives from what is known about primary visual cortex, where neural activity represents patterns of light. Yet it is unclear how well the analogy between motor and visual cortex holds. Single-neuron responses in motor cortex are complex, and there is marked disagreement regarding which movement parameters are represented. A better analogy might be with other motor systems, where a common principle is rhythmic neural activity. Here we find that motor cortex responses during reaching contain a brief but strong oscillatory component, something quite unexpected for a non-periodic behaviour. Oscillation amplitude and phase followed naturally from the preparatory state, suggesting a mechanistic role for preparatory neural activity. These results demonstrate an unexpected yet surprisingly simple structure in the population response. This underlying structure explains many of the confusing features of individual neural responses. 相似文献
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Zhang B Cunningham MA Nichols WC Bernat JA Seligsohn U Pipe SW McVey JH Schulte-Overberg U de Bosch NB Ruiz-Saez A White GC Tuddenham EG Kaufman RJ Ginsburg D 《Nature genetics》2003,34(2):220-225
Mutations in LMAN1 (also called ERGIC-53) result in combined deficiency of factor V and factor VIII (F5F8D), an autosomal recessive bleeding disorder characterized by coordinate reduction of both clotting proteins. LMAN1 is a mannose-binding type 1 transmembrane protein localized to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC; refs. 2,3), suggesting that F5F8D could result from a defect in secretion of factor V and factor VIII (ref. 4). Correctly folded proteins destined for secretion are packaged in the ER into COPII-coated vesicles, which subsequently fuse to form the ERGIC. Secretion of certain abundant proteins suggests a default pathway requiring no export signals (bulk flow; refs. 6,7). An alternative mechanism involves selective packaging of secreted proteins with the help of specific cargo receptors. The latter model would be consistent with mutations in LMAN1 causing a selective block to export of factor V and factor VIII. But approximately 30% of individuals with F5F8D have normal levels of LMAN1, suggesting that mutations in another gene may also be associated with F5F8D. Here we show that inactivating mutations in MCFD2 cause F5F8D with a phenotype indistinguishable from that caused by mutations in LMAN1. MCFD2 is localized to the ERGIC through a direct, calcium-dependent interaction with LMAN1. These findings suggest that the MCFD2-LMAN1 complex forms a specific cargo receptor for the ER-to-Golgi transport of selected proteins. 相似文献
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