| 6 | Dual-energy X-ray absorptiometry scans accurately predict differing body fat content in live sheep显示文摘Background: There is considerable interest in implementing mobile scanning technology for on-farm body composition analysis on live animals.These experiments evaluated the use of dual energy X-ray absorptiometry(DXA) as an accurate method of total body fat measurement in live sheep.Results: In Exp.1,visceral and whole body fat analysis was undertaken in sheep with body condition scores(BCS)in the range 2 to 3.25(scale 1: thin to 5: fat).The relationship of BCS was moderately correlated with visceral fat depot mass(r = 0.59,P < 0.01,n = 24) and whole body fat(r = 0.70,P < 0.001,n = 24).In Exp.2,sheep with BCS in the range 2.25 to 3.75 were blood sampled to analyse circulating leptin concentrations,and were DXA scanned immediately post mortem for total body fat.Plasma leptin concentrations had low correlations with BCS(r = 0.50,P < 0.05,n = 17) and DXA body fat(r = 0.42,P < 0.05,n = 17),and no correlation with chemical body fat(r = 0.17,P > 0.05,n = 9).There was a moderate correlation between DXA body fat and BCS(r = 0.70,P < 0.01,n = 17),and DXA body fat was highly correlated with chemical body fat(r = 0.81,P < 0.001,n = 9).In Exp.3,a series of five DXA scans,at 8-week intervals,was performed on growing sheep over a 32-week period.The average BCS ranged from 2.39 ± 0.07(S.E.M.) to 3.05 ± 0.11 and the DXA body fat(%) ranged from 16.8 ± 0.8 to 24.2 ± 1.2.There was a moderate correlation between DXA body fat and BCS over the 32 weeks(r = 0.61,P < 0.001,n = 24).Conclusions: Overall,these experiments indicated that there was good agreement between BCS,DXA and chemical analysis for measuring total body fat in sheep,and that DXA scanning is a valid method for longitudinal measurement of total body fat in live sheep. | David W Miller Ellen J Bennett Joanne L Harrison Fiona Anderson Clare L Adam | 2019 | Journal of Animal Science and Biotechnology2019，10，1： | 0 |
| 7 | 支气管扩张剂治疗与哮喘死亡:病例对照研究显示文摘目的研究支气管扩张剂的应用与哮喘死亡的相关性。设计方法病例对照研究。研究设置英国33个卫生权威机构或卫生组织。研究对象532例年龄小于65岁而且死于哮喘的患者和532例对照病例,他们是与前者在住院日期、年龄和地区相匹配的哮喘住院患者。主要结局指标应用比值比(OR)方法研究哮喘死亡与应用支气管扩张剂及其他治疗的相关性,同时对始发年龄、先前住院情况、相关的慢性阻塞性肺病(COPD)和其他种类药物进行校正,以分析这种相关性的敏感性。结果通过校正发现哮喘死亡与患者在过去4~12月内的用药无明显相关性,而与患者过去1~5年内吸入短效β2激动剂呈正相关(OR2.05,95%CI1.26~3.33),这种相关性主要表现在45~64岁年龄组,但与过去1~5年内使用抗生素呈负相关(0.59,0.39~0.89),这种负相关在45岁以下的患者表现更显著。年龄对各个时期的用药都有影响,在45岁以下年龄组口服类固醇激素与哮喘死亡呈负相关。哮喘死亡与患者过去1~5年内使用长效β2激动剂呈负相关,而与使用甲基黄嘌呤呈正相关,但它们无显著意义。结论没有证据显示中长期吸入长效β2激动剂有负面效应。短效β2激动剂与死亡呈正相关有多种解释,仅其中一项是它的直接负面效应。 | H Ross Anderson Jon G Ayres Patricia M Sturdy J Martin Bland Barbara K Butland Clare Peckitt Jennifer C Taylor Christina R Victor 王同德(译) 代华平(校) | 2005 | 英国医学杂志中文版2005，8，4： | 0 |
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