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Historically, patients with prior aortic valve replacements who subsequently present with an ascending aortic aneurysm require placement of a valve conduit. However, if the patient has a functional mechanical valve with proven long-term durability, an attempt can be made to preserve the intact valve and to graft the aneurysmal aortic root. The case is described of a patient with a previously placed Starr-Edwards aortic valve who subsequently developed a 6-cm ascending aortic aneurysm. By removing the valve ball and using the existing sewing ring, a proximal graft anastomosis was created with ease, eliminating valve excision.  相似文献   
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A fraction of enzymatically monodispersed rat thyrocytes from untreated animals clonally proliferate into thyroid follicular units following transplantation into the subcutaneous fat pads of syngeneic recipients. During the induction of experimental goiters in rats either with 3-amino-1,2,4-triazole/iodine sufficient diet or KClO4/Remington low iodine diet, the clonogenic fractions of cells from aminotriazole goiters decreased to 1.9 x 10(-4) and KClO4 goiters to 9.8 x 10(-5) as compared to 5.8 x 10(-3) for cells from age-matched controls during the growth phase of goitrogenesis. With continued aminotriazole treatment after thyroid hyperplasia had ceased, the clonogenic fraction increased to 2.0 x 10(-3) while continued KClO4 treatment had little further effect. The changes in the clonogenic fraction induced by both regimens were reversed during involution; goitrogenic rechallenge of involuted glands led to changes in the clonogenic fraction similar to that noted during the initial challenge. The clonogenic fractions of cells from aminotriazole goiters were greater than that of cells from KClO4 goiters at all time points examined despite similar TSH levels in situ. We conclude that the rat thyroid contains a hierarchy of cells with different proliferative capacities and that the clonogenic thyrocytes possess many of the attributes of a stem-cell.  相似文献   
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BackgroundPressure injuries have a major impact on patients and healthcare organisations. The complications of pressure injuries increase morbidity and mortality rates and are costly to individuals and healthcare systems. The total prevalence rate of pressure injuries within acute care hospitals in Australia and New Zealand is unknown, and despite a focus on prevention, pressure injuries still occur within these hospital settings.AimTo report the prevalence of pressure injuries within acute care settings in Australian and New Zealand hospitals and to identify the stage and location of pressure injuries and analyse the methods used to conduct pressure injury point prevalence studies.MethodsA systematic review of studies published in CINAHL, MEDLINE and Cochrane databases and a two-part grey literature search, including a customised Google search and a targeted website search, was undertaken up to July 2019. The systematic review was prospectively registered with PROSPERO (CRD42018105566).FindingsThe overall prevalence of pressure injuries in acute-care hospitals in Australia and New Zealand is 12.9% (95% CI, 9.5%–16.8%) and the hospital-acquired pressure injury prevalence is 7.9% (95% CI, 5.7%–10.3%). Stage I and stage II are the most common pressure injuries. The most frequent locations for pressure injuries are the sacrum/buttock/coccyx area (41%) and the heels (31%). The reporting of details about methodology varies considerably between studies.DiscussionPressure injuries remain a significant problem within acute-care hospital settings. Total prevalence rates are decreasing over time with the numbers of stage I and II pressure injuries decreasing faster than other pressure injuries.ConclusionThe findings from this study can be used to set performance benchmarks within acute-care hospitals in Australia and New Zealand. Pressure injuries are preventable and pressure injury prevalence studies can be used to monitor the effectiveness of nursing care processes to improve patient outcomes.  相似文献   
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