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81.
David M Markusic Niek P van Til Johan K Hiralall PJ Oude Ronald Elferink Jurgen Seppen 《BMC biotechnology》2009,9(1):85
Background
Lentiviral vectors are well suited for gene therapy because they can mediate long-term expression in both dividing and nondividing cells. However, lentiviral vectors seem less suitable for liver gene therapy because systemically administered lentiviral vectors are preferentially sequestered by liver macrophages. This results in a reduction of available virus and might also increase the immune response to the vector and vector products. 相似文献82.
Background
Leucine-rich repeats are one of the more common modules found in proteins. The leucine-rich repeat consensus motif is LxxLxLxxNxLxxLxxLxxLxx- where the first 11–12 residues are highly conserved and the remainder of the repeat can vary in size Leucine-rich repeat proteins have been subdivided into seven subfamilies, none of which include members of the epidermal growth factor receptor or insulin receptor families despite the similarity between the 3D structure of the L domains of the type I insulin-like growth factor receptor and some leucine-rich repeat proteins. 相似文献83.
A Bell OA Rodríguez LA de Castro e Paula MB Padua J Hernández-Cerón CG Gutiérrez A De Vries PJ Hansen 《BMC veterinary research》2008,4(1):22
Background
Results regarding the use of bovine somatotropin for enhancing fertility in dairy cattle are variable. Here, the hypothesis was tested that a single injection of a sustained-release preparation of bovine somatotropin (bST) during the preovulatory period would improve pregnancy success of lactating dairy cows at first service.Results
The first experiment was conducted in a temperate region of Mexico. Cows inseminated following natural estrus or timed artificial insemination were given a single injection of bST or a placebo injection at insemination (n = 100 cows per group). There was no significant difference between bST and control groups in the proportion of inseminated cows diagnosed pregnant (29 vs 31% pregnant). The second experiment was performed during heat stress in Florida. Cows were subjected to an ovulation synchronization regimen for first insemination. Cows treated with bST received a single injection at 3 days before insemination. Controls received no additional treatment. As expected, bST did not increase vaginal temperature. Treatment with bST did not significantly increase the proportion of inseminated cows diagnosed pregnant although it was numerically greater for the bST group (24.2% vs 17.8%, 124–132 cows per group). There was a tendency (p = 0.10) for a smaller percent of control cows to have high plasma progesterone concentrations (≥ 1 ng/ml) at Day 7 after insemination than for bST-treated cows (72.6 vs 81.1%). When only cows that were successfully synchronized were considered, the magnitude of the absolute difference in the percentage of inseminated cows that were diagnosed pregnant between bST and control cows was reduced (24.8 vs 22.4% pregnant for bST and control).Conclusion
Results failed to indicate a beneficial effect of bST treatment on fertility of lactating dairy cows.84.
Bayesian analysis of factorial experiments by mixture modelling 总被引:3,自引:0,他引:3
85.
86.
D. O. Verschure B. L. F. van Eck-Smit G. A. Somsen R. J. J. Knol H. J. Verberne 《Netherlands heart journal》2016,24(12):701-708
Heart failure is a life-threatening disease with a growing incidence in the Netherlands. This growing incidence is related to increased life expectancy, improvement of survival after myocardial infarction and better treatment options for heart failure. As a consequence, the costs related to heart failure care will increase. Despite huge improvements in treatment, the prognosis remains unfavourable with high one-year mortality rates. The introduction of implantable devices such as implantable cardioverter defibrillators (ICD) and cardiac resynchronisation therapy (CRT) has improved the overall survival of patients with chronic heart failure. However, after ICD implantation for primary prevention in heart failure a high percentage of patients never have appropriate ICD discharges. In addition 25–50?% of CRT patients have no therapeutic effect. Moreover, both ICDs and CRTs are associated with malfunction and complications (e.?g. inappropriate shocks, infection). Last but not least is the relatively high cost of these devices. Therefore, it is essential, not only from a clinical but also from a socioeconomic point of view, to optimise the current selection criteria for ICD and CRT. This review focusses on the role of cardiac sympathetic hyperactivity in optimising ICD selection criteria. Cardiac sympathetic hyperactivity is related to fatal arrhythmias and can be non-invasively assessed with 123I-meta-iodobenzylguanide (123I-mIBG) scintigraphy. We conclude that cardiac sympathetic activity assessed with 123I-mIBG scintigraphy is a promising tool to better identify patients who will benefit from ICD implantation. 相似文献
87.
Primary antibody-forming cells and secondary B cells are generated from separate precursor cell subpopulations 总被引:22,自引:0,他引:22
Two precursor cell subpopulations have been isolated from the spleen cells of nonimmune mice. The major B cell subpopulation binds high levels of the J11D monoclonal antibody and, upon T cell-dependent antigenic stimulation, gives rise to primary antibody-forming cell clones but not secondary B cells. A minority of the 10%-14% of Ia+ precursors that bind low levels of J11D (J11Dlo) also generate antibody-forming cell clones after primary stimulation. However, over 70% of J11Dlo precursors yield no primary antibody-forming cell clones but instead give rise to secondarily responsive B cells. The existence of a distinct precursor cell subpopulation that is responsible for the generation of B cell memory is further evidenced by the distribution of variable region clonotypes among J11Dlo primary precursors, which resembles the clonotype patterns of secondary B cells, and by the accumulation of somatic mutations in their clonal progeny. 相似文献
88.
89.
Ulysses Bernardet Sergi Bermúdez i Badia Paul FMJ Verschure 《Theorie in den Biowissenschaften》2008,127(2):163-175
Returning to the point of departure after exploring the environment is a key capability for most animals. In the absence of
landmarks, this task will be solved by integrating direction and distance traveled over time. This is referred to as path
integration or dead reckoning. An important question is how the nervous systems of navigating animals such as the 1 mm3 brain of ants can integrate local information in order to make global decision. In this article we propose a neurobiologically
plausible system of storing and retrieving direction and distance information. The path memory of our model builds on the
well established concept of population codes, moreover our system does not rely on trigonometric functions or other complex
non-linear operations such as multiplication, but only uses biologically plausible operations such as integration and thresholding.
We test our model in two paradigms; in the first paradigm the system receives input from a simulated compass, in the second
paradigm, the model is tested against behavioral data recorded from 17 ants. We were able to show that our path memory system
was able to reliably encode and compute the angle of the vector pointing to the start location, and that the system stores
the total length of the trajectory in a dependable way. From the structure and behavior of our model, we derive testable predictions
both at the level of observable behavior as well as on the anatomy and physiology of its underlying neuronal substrate. 相似文献
90.
Wyss R König P Verschure PF 《Proceedings. Biological sciences / The Royal Society》2004,271(Z3):S50-S52
The control of behaviour is usually understood in terms of three distinct components: sensory processing, decision making and movement control. Recently, this view has been questioned on the basis of physiological and behavioural data, blurring the distinction between these three stages. This raises the question to what extent the motor system itself can contribute to the interpretation of behavioural situations. To investigate this question we use a neural model of sensory motor integration applied to a behaving mobile robot performing a navigation task. We show that the population response of the motor system provides a substrate for the categorization of behavioural situations. This categorization allows for the assessment of the complexity of a behavioural situation and regulates whether higher-level decision making is required to resolve behavioural conflicts. Our model lends credence to an emerging reconceptualization of behavioural control where the motor system can be considered as part of a high-level perceptual system. 相似文献