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No technique will serve the needs of all patients requiring a reduction mammaplasty and mastopexy. However, the modified, inferiorly-based dermal flap technique appears to us to offer the most advantages and the greatest latitude for a predictable breast reduction in most of these patients.  相似文献   

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Wilmut I 《Cloning》2001,3(2):39-40
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Cardiac magnetic resonance (CMR) imaging is increasingly used in daily clinical practice. However, its safety and impact on patient management have not been studied in large populations. In a recent online issue of the Journal of the American Cardiology (JACC, August 2009) the EuroCMR (European Cardiovascular Magnetic Resonance) registry evaluated indications, image quality, safety, and impact on patient management of routine CMR imaging in 11,040 patients from 20 European centres (including the VU Medical Centre, Amsterdam, van Rossum).  相似文献   

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Prophylactic bilateral mastectomy has been demonstrated to reduce breast cancer incidence in women with a high inherited susceptibility to breast cancer. For the majority of high-risk women, however, bilateral prophylactic mastectomy is not an acceptable option for primary prevention of breast cancer. Several epidemiological follow-up studies have indicated that there may be a substantial reduction in breast cancer risk among women who have undergone breast reduction surgery. The authors reviewed the evidence from these studies, with emphasis on the problems inherent in interpreting the results of nonexperimental studies of elective medical procedures. Although such observational studies cannot demonstrate definitively that reduction mammaplasty reduces the risk of breast cancer, the evidence from these studies is sufficiently strong to warrant the evaluation of breast reduction surgery as an option for primary prevention in clinical studies of women at increased risk of breast cancer. The availability of a more acceptable surgical option for primary prevention of breast cancer could increase the number of women willing to choose risk reduction surgery and thus may result in an overall reduction in breast cancer mortality among high-risk women.  相似文献   

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Small and isolated populations face threats from genetic drift and inbreeding. To rescue populations from these threats, conservation biologists can augment gene flow into small populations to increase variation and reduce inbreeding depression. Spectacular success stories include greater prairie chickens in Illinois (Westermeier et al. 1998 ), adders in Sweden (Madsen et al. 1999 ) and panthers in Florida (Johnson et al. 2010 ). However, we also know that performing such crosses risks introducing genes that may be poorly adapted to local conditions or genetic backgrounds. A classic example of such ‘outbreeding depression’ occurred when different subspecies of ibex from Turkey and the Sinai were introduced to assist recovery of an ibex population in Czechoslovakia (Templeton 1986 ). Despite being fertile, the hybrids birthed calves too early, causing the whole population to disappear. In the face of uncertainty, conservation biologists have tended to respect genetic identity, shying away from routinely crossing populations. In this issue of Molecular Ecology, Frankham ( 2015 ) compiles empirical data from experimental studies to assess the costs and benefits of between‐population crosses (Fig.  1 ). Crosses screened to exclude those involving highly divergent populations or distinct habitats show large heterosis with few apparent risks of outbreeding depression. This leads Frankham to advocate for using assisted gene flow more widely. But do the studies analysed in this meta‐analysis adequately test for latent outcrossing depression?  相似文献   

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The effects of foliar- and root-feeding insects on the dynamics of an early successional plant community, representing the first four years of colonisation, were examined. Subterranean insect herbivores were found to increase in density with increasing successional age of the plant community. In early succession, chewing insects mainly Coleoptera (Scarabaeidae) and Diptera (Tipulidae) were dominant. This was in direct contrast to the foliar-feeding insects, which were dominated by sap-feeders (mainly Auchenorrhynchan Hemiptera).Reduction of both foliar- and root-feeding insects with appropriate insecticides had different, but dramatic, consequences for the plant community. Reducing foliar herbivory resulted in large increases in perennial grass growth, with plant species richness being reduced as the grasses outcompeted the forbs. Reducing subterranean herbivory prolonged the persistence of annual forbs, greatly increased perennial forb colonisation and, as a consequence, plant species richness. Foliar-feeding insects thus act to delay succession by slowing grass colonisation. In contrast, root-feeding insects accelerate succession by reducing forb persistence and colonisation. The structure of early successional plant communities is therefore modified by the two modes of herbivory.This paper was presented at the Vth International Congress of Ecology (INTECOL), Japan, 1990, entitled Successional Communities of Plants and Insects.  相似文献   

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Remarkable progress has been made in transfusion safety from infection over the past three decades. Donor deferrals for at-risk behaviors, the introduction of more-sensitive viral-screening assays and the recent introduction of nucleic-acid amplification technology have nearly eliminated transmission of HIV and hepatitis C virus (HCV) by blood transfusion in North America. Nevertheless, risks of other infectious agents for which such robust screening tools have not been developed, such as bacteria and parasites, still remain. As a result of these successes, the non-infectious risks such as misidentification of patients and inadequate and inappropriate transfusion have become the primary sources of transfusion risk.  相似文献   

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