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It now seems technically feasible to culture human embryos beyond the “fourteen‐day limit,” which has the potential to increase scientific understanding of human development and perhaps improve infertility treatments. The fourteen‐day limit was adopted as a compromise but subsequently has been considered an ethical line. Does it remain relevant in light of technological advances permitting embryo maturation beyond it? Should it be changed and, if so, how and why? What justifications would be necessary to expand the limit, particularly given that doing so would violate some people's moral commitments regarding human embryos? Robust stakeholder engagement preceded adoption of the fourteen‐day limit and should arguably be part of efforts to reassess it. Such engagement could also consider the need for enhanced oversight of human embryo research. In the meantime, developing and implementing reliable oversight systems should help foster high‐quality research and public confidence in it.  相似文献   
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Phosphorylated forms of microtubule-associated protein tau accumulate in neurofibrillary tangles in Alzheimer's disease. To investigate the effects of specific phosphorylated tau residues on its function, wild type or phosphomutant tau was expressed in cells. Elevated tau phosphorylation decreased its microtubule binding and bundling, and increased the number of motile tau particles, without affecting axonal transport kinetics. In contrast, reducing tau phosphorylation enhanced the amount of tau bound to microtubules and inhibited axonal transport of tau. To determine whether differential tau clearance is responsible for the increase in phosphomimic tau, we inhibited autophagy in neurons which resulted in a 3-fold accumulation of phosphomimic tau compared with wild type tau, and endogenous tau was unaffected. In autophagy-deficient mouse embryonic fibroblasts, but not in neurons, proteasomal degradation of phosphomutant tau was also reduced compared with wild type tau. Therefore, autophagic and proteasomal pathways are involved in tau degradation, with autophagy appearing to be the primary route for clearing phosphorylated tau in neurons. Defective autophagy might contribute to the accumulaton of tau in neurodegenerative diseases.  相似文献   
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Reviews of the efficacy of acupuncture as a treatment for acute low back pain have concluded that there is insufficient evidence for its efficacy and that more research is needed to evaluate it. A multicentre randomized controlled trial was conducted at 4 primary-care centres in Spain to evaluate the effects of acupuncture in patients with acute nonspecific low back pain in the context of primary care. A total of 275 patients with nonspecific acute low back pain (diagnosed by their general practitioner) were recruited and assigned randomly to 4 different groups: conventional treatment either alone or complemented by 5 sessions over a 2-week period of true acupuncture, sham acupuncture, or placebo acupuncture per patient. Patients were treated from February 2006 to January 2008. The primary outcome was the reduction in Roland Morris Disability Questionnaire scores of 35% or more after 2weeks' treatment. The patients in the 3 types of acupuncture groups were blinded to the treatments, but those who received conventional treatment alone were not. In the analysis adjusted for the total sample (true acupuncture relative risk 5.04, 95% confidence interval 2.24-11.32; sham acupuncture relative risk 5.02, 95% confidence interval 2.26-11.16; placebo acupuncture relative risk 2.57 95% confidence interval 1.21-5.46), as well as for the subsample of occupationally active patients, all 3 modalities of acupuncture were better than conventional treatment alone, but there was no difference among the 3 acupuncture modalities, which implies that true acupuncture is not better than sham or placebo acupuncture.  相似文献   
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Objective

To measure endometrial thickness and characterize ultrasonographic endometrial images induced by tamoxifen, as well as to determine changes in ultrasonographic patterns throughout treatment.

Patients and methods

We analyzed 278 patients with breast cancer between 1995 and 2000 under adjuvant therapy with tamoxifen for 5 years. Annual ultrasonographic examination was performed. Endometrial thickness and the morphological endometrial patterns in stored ultrasonographic images were retrospectively analyzed.

Results

Endometrial thickness significantly increased during treatment from a mean of 7.84 mm in the first year to 16.67 mm in the fifth year. Five endometrial patterns were found on ultrasonography in patients receiving tamoxifen: linear, heterogeneous-hyperechoic, homogeneoushyperechoic, endometrial polyp, and suspicious for malignancy. The homogeneous-hyperechoic pattern predominated in the first year and the heterogeneous-hyperechoic pattern in the fifth year.

Conclusions

Tamoxifen increases endometrial thickness in the course of treatment and induces five ultrasonographic patterns which change year-by-year.  相似文献   
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