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排序方式: 共有907条查询结果,搜索用时 31 毫秒
81.
Chimowitz MI Lynn MJ Derdeyn CP Turan TN Fiorella D Lane BF Janis LS Lutsep HL Barnwell SL Waters MF Hoh BL Hourihane JM Levy EI Alexandrov AV Harrigan MR Chiu D Klucznik RP Clark JM McDougall CG Johnson MD Pride GL Torbey MT Zaidat OO Rumboldt Z Cloft HJ;SAMMPRIS Trial Investigators 《The New England journal of medicine》2011,365(11):993-1003
82.
Mocco J Tawk RG Jahromi BS Samuelson RM Siddiqui AH Hopkins LN Levy EI 《Journal of neurosurgery》2009,110(1):30-34
OBJECT: Endovascular treatment of acute thromboembolic stroke is a rapidly developing field that appears to hold great promise. Young patients may be particularly suited to benefit from endovascular acute stroke therapy. The authors sought to identify outcomes in young patients with thromboembolic stroke who underwent endovascular intervention. METHODS: The authors retrospectively reviewed a prospectively collected endovascular intervention registry of patients with ischemic strokes treated at a single large-volume institution between December 2000 and June 2007 to identify patients 18-35 years of age who were treated for thromboembolic stroke. Data are presented as the mean +/- standard deviation unless otherwise noted. RESULTS: Seven young patients underwent 8 consecutive endovascular interventions for thromboembolic stroke (mean age 26 +/- 6 years; 5 women). The National Institutes of Health Stroke Scale score at presentation was 13 +/- 4.3 (median 13). All patients presented within 6 hours of symptom onset. Revascularization was attempted with mechanical thrombectomy/disruption, intraarterial thrombolysis, and/or angioplasty, with or without stent placement. The modified Rankin Scale (mRS) score at discharge was 2.2 +/- 1.5 (median 1.5), with 5 patients (62.5%) achieving independence at discharge (mRS Score 0-2). There were no deaths. Hospital length of stay was 6.5 +/- 3.7 days (4.4 +/- 1.5 days for patients with an mRS score of 0-2; 10 +/- 3.6 days for patients with an mRS score of 4). All patients became independent and had reached an mRS score of < or = 2 at last follow-up evaluation (29 +/- 25 months). CONCLUSIONS: The data demonstrate the relative safety of endovascular intervention in young patients with thromboembolic cerebral ischemia and may suggest a potential benefit in outcome. Further investigation is indicated with larger numbers of patients and an appropriate control population. 相似文献
83.
Varying environments can speed up evolution 总被引:4,自引:0,他引:4
Kashtan N Noor E Alon U 《Proceedings of the National Academy of Sciences of the United States of America》2007,104(34):13711-13716
Simulations of biological evolution, in which computers are used to evolve systems toward a goal, often require many generations to achieve even simple goals. It is therefore of interest to look for generic ways, compatible with natural conditions, in which evolution in simulations can be speeded. Here, we study the impact of temporally varying goals on the speed of evolution, defined as the number of generations needed for an initially random population to achieve a given goal. Using computer simulations, we find that evolution toward goals that change over time can, in certain cases, dramatically speed up evolution compared with evolution toward a fixed goal. The highest speedup is found under modularly varying goals, in which goals change over time such that each new goal shares some of the subproblems with the previous goal. The speedup increases with the complexity of the goal: the harder the problem, the larger the speedup. Modularly varying goals seem to push populations away from local fitness maxima, and guide them toward evolvable and modular solutions. This study suggests that varying environments might significantly contribute to the speed of natural evolution. In addition, it suggests a way to accelerate optimization algorithms and improve evolutionary approaches in engineering. 相似文献
84.
Fecal incontinence is a common clinical problem that often is frustrating to the patient and treating physician. Nonsurgical management for fecal incontinence includes dietary manipulation, Kegel exercises, perianal skin care, and biofeedback therapy. Pharmacotherapies often are used to assist in management of fecal incontinence. A variety of pharmacotherapies have been utilized for the management of fecal incontinence; limited data from randomized, placebo-controlled trials are available. This is a review of the existing literature on clinical trials of several classes of drugs and other medical therapies that may be beneficial for patients with fecal incontinence. The information in this article was obtained by a MEDLINE search for all clinical trials of drug therapy for fecal incontinence. These treatments and the existing data on their use are summarized. Treatments reviewed include stool bulking agents, with an emphasis on the most promising effect obtained with calcium polycarbophil, constipating agents, including loperamide, codeine, amitriptyline, atropine, and diphenoxylate agents injected into the anal sphincter, drugs to enhance anal sphincter function, including topical phenylepherine and oral sodium valproate, and trials of fecal disimpaction. A new classification to easily remember the treatment categories for this condition, based on the "ABCs of treatment for fecal incontinence," has been introduced into the structure of this review. 相似文献
85.
The nervous system may be involved in up to 30% of patients with Sjogren’s syndrome (SS). We describe three patients with
Sjogren’s syndrome and a concomitant parkinsonian syndrome. Elevated titers of anti-β2-glycoprotein I IgG were found in the serum of all three patients. This autoantibody is strongly associated with anticardiolipin
(aCL) antibodies, antiphospholipid syndrome (APS), and thromboembolic phenomena, but its role in the pathogenesis of the parkinsonian
disorder in SS is unclear. These patients may present a subtype of SS patients in which the presence of aCL antibodies is
associated with central nervous system involvement predominantly in the basal ganglia.
Sharon Hassin-Baer and Levy Yair contributed equally to this work. 相似文献
86.
Sharon Elad Moshe J. Gomori Noa Ben-Ami Silvina Friedlander-Barenboim Eran Regev Towy S. Lazarovici Noam Yarom 《Clinical oral investigations》2010,14(1):43-50
The aim of this study was to correlate clinical and computerized tomography (CT) features of bisphosphonate-related osteonecrosis of the jaws (BRONJ). All ONJ patients for whom there was complete CT scan imaging were eligible. Selected clinical parameters retrieved from their medical records were analyzed for correlation with CT parameters. The clinical presentation of BRONJ was supported by findings in CT imaging in 78.3%. The lesion’s size on CT correlated with the presence of purulent secretion (p?=?0.03). When sequestrum was present, the median lesion’s size on CT was relatively big (28 mm, range 21–43 mm). The mandibular canal cortex was never breached. CT has reasonable detection competence for diagnosing BRONJ. Purulent secretion indicates the likelihood that a more extensive involvement will be displayed on CT. A large lesion on CT should raise the index of suspicion for sequestrum. The CT appearance of a continuous cortex of the mandibular canal may serve as a differential parameter between BRONJ and metastasis to the jaw. 相似文献
87.
Arren Bar-Even Elad Noor Nathan E. Lewis Ron Milo 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(19):8889-8894
Carbon fixation is the process by which CO2 is incorporated into organic compounds. In modern agriculture in which water, light, and nutrients can be abundant, carbon fixation could become a significant growth-limiting factor. Hence, increasing the fixation rate is of major importance in the road toward sustainability in food and energy production. There have been recent attempts to improve the rate and specificity of Rubisco, the carboxylating enzyme operating in the Calvin–Benson cycle; however, they have achieved only limited success. Nature employs several alternative carbon fixation pathways, which prompted us to ask whether more efficient novel synthetic cycles could be devised. Using the entire repertoire of approximately 5,000 metabolic enzymes known to occur in nature, we computationally identified alternative carbon fixation pathways that combine existing metabolic building blocks from various organisms. We compared the natural and synthetic pathways based on physicochemical criteria that include kinetics, energetics, and topology. Our study suggests that some of the proposed synthetic pathways could have significant quantitative advantages over their natural counterparts, such as the overall kinetic rate. One such cycle, which is predicted to be two to three times faster than the Calvin–Benson cycle, employs the most effective carboxylating enzyme, phosphoenolpyruvate carboxylase, using the core of the naturally evolved C4 cycle. Although implementing such alternative cycles presents daunting challenges related to expression levels, activity, stability, localization, and regulation, we believe our findings suggest exciting avenues of exploration in the grand challenge of enhancing food and renewable fuel production via metabolic engineering and synthetic biology. 相似文献
88.
Gitt Panitchayangkoon Dugan Hayes Kelly A. Fransted Justin R. Caram Elad Harel Jianzhong Wen Robert E. Blankenship Gregory S. Engel 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(29):12766-12770
Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center that stores energy from the photon in chemical bonds. This process occurs with near-perfect quantum efficiency. Recent experiments at cryogenic temperatures have revealed that coherent energy transfer—a wave-like transfer mechanism—occurs in many photosynthetic pigment-protein complexes. Using the Fenna–Matthews–Olson antenna complex (FMO) as a model system, theoretical studies incorporating both incoherent and coherent transfer as well as thermal dephasing predict that environmentally assisted quantum transfer efficiency peaks near physiological temperature; these studies also show that this mechanism simultaneously improves the robustness of the energy transfer process. This theory requires long-lived quantum coherence at room temperature, which never has been observed in FMO. Here we present evidence that quantum coherence survives in FMO at physiological temperature for at least 300 fs, long enough to impact biological energy transport. These data prove that the wave-like energy transfer process discovered at 77 K is directly relevant to biological function. Microscopically, we attribute this long coherence lifetime to correlated motions within the protein matrix encapsulating the chromophores, and we find that the degree of protection afforded by the protein appears constant between 77 K and 277 K. The protein shapes the energy landscape and mediates an efficient energy transfer despite thermal fluctuations. 相似文献
89.
90.
Amy D. Shapiro Charles Nakar Joseph M. Parker Karen Thibaudeau Roberto Crea Per Morten Sandset 《Haemophilia》2023,29(6):1556-1564