论文快速发表网

社科类论文科技类论文医学类论文管理类论文教育类论文农林类论文新闻类论文建筑类论文文艺类论文法学类论文

EI Compendex Source List（2022年1月） EI Compendex Source List（2020年1月） EI Compendex Source List（2019年5月） EI Compendex Source List（2018年9月） EI Compendex Source List（2018年5月） EI Compendex Source List（2018年1月）中国科学引文数据库来源期刊列 CSSCI(2017-2018)及扩展期刊目录 2017年4月7日EI检索目录（最新） 2017年3月EI检索目录最新公布北大中文核心期刊目录 SCI期刊（含影响因子）

本站服务项目浅谈青年教师如何开展教科研大学青年教师如何处理教学和科

论文范文

Post Mortem Leukocyte Scintigraphy in Juvenile Pigs with Experimentally Induced Osteomyelitis 时间:2017-09-18 14:21 来源:未知作者:admin 点击: 次 Abstract:We have previously demonstrated that 111In-labeled autologous leukocyte scintigraphy is able to detect osteomyelitis in living juvenile pigs. In animal research studies, it may well be an advantage if the animals could be scanned after euthanasia. Applying traditional scanning of living animals to euthanized animals will render anaesthesia unnecessary and be ideal for obtaining good and reliable scans for the correct interpretation of imaging afterwards, since the animals do not move. The autologous leukocytes of the pigs were collected, marked with 111In, and reinjected into the pigs and allowed for homing to the site of infections as usual while the pigs were alive. In this study, we demonstrate that it is possible to perform SPECT/CT with 111In-labelled autologous leukocytes almost 24 hrs after euthanasia with the same detectability of osteomyelitic lesions as in living pigs (78% versus 79%). The pigs in this study had exactly the same experimental conditions as the living pigs and were examined in parallel with the living pigs except for euthanasia prior to the leukocyte scan and that no PET/CT scans were performed.
1. Introduction
Chronic osteomyelitis is a progressive inflammatory process caused most often by Staphylococcus aureus (S. aureus), resulting in bone destruction and sequestrum formation, which may maintain the infection. The “gold standard” for the diagnosis of chronic osteomyelitis is the presence of positive bone cultures and histopathologic examination of the bone, but noninvasive diagnostic imaging is preferred in humans. We have thus previously refined a pig-model for haematogenous spread of osteomyelitis [1, 2] and used this for examining suitable tracers for better noninvasive imaging [3–5]. In the model, we injected S. aureus unilaterally into the femoral artery of female juvenile domestic pigs and tested various radioactive tracers to identify the most useful diagnostic imaging protocol for bone infections. This aim necessitated a rather busy scanning protocol and prolonged anaesthesia, and due to biological variance and experiment planning we had to infect more pigs that finally were anaesthetized and scanned; the surplus of pigs was euthanized prior to the scans. We, therefore, were curious to see if it was possible to do post mortem scintigraphy of the extra pigs using a tracer with a long half-life injected before euthanasia, thus leaving no pig unused and delaying the scintigraphy to a later and more convenient time.
Naturally occurring S. aureus infection in pigs usually manifests as sepsis, which includes development of osteomyelitis. Johansen et al. [6] demonstrated that as in children circulating microorganisms tend to start infections in the metaphyseal ends of the long bones in juvenile pigs. This is probably due to seeding of a septic embolus aided by the slow circulation in the capillary loops in the metaphyseal growth zone making juvenile pigs particularly susceptible to epiphyseal spread and arthritis of the adjacent joint.
111In-leukocyte scintigraphy is a diagnostic imaging tool that displays the distribution of radiolabelled autologous leukocytes in the body. Regional or whole-body planar and/or single photon emission computed tomography (SPECT) scintigraphy perhaps combined with computed tomography (CT) of specific anatomic regions can be obtained for suspected infection/inflammation. Leukocytes are separated from plasma for labelling with 111In. 111In decays by electron capture emitting two gamma photons of 173 keV and 247 keV. The physical half-life is 67 hrs. 111In is bound to a lipid-soluble complex that chelates metal ions. The 111Indium oxine complex diffuses through the cell membrane and once intracellular, the complex dissociates, and 111Indium binds nuclear and cytoplasmic proteins. After labelling and reinjection radiolabelled leukocytes of humans are distributed to the blood pool, lungs, and the reticuloendothelial system of the liver, spleen, bone marrow, and major blood vessels. Imaging is performed 18–24 hrs after injection when lung, blood pool, bowel, and bladder activity are not normally seen.
We have previously demonstrated by SPECT/CT of living pigs that it is possible to mark porcine leukocytes with 111In, that the marked porcine leukocytes were capable of homing to sites of osteomyelitic lesions, and that the biodistribution is comparable to the human biodistribution [5]. The major difference was the accumulation of activity in the lungs of juvenile pigs, which is only a transient phenomenon in healthy human lungs. The reason for this difference is that the lungs of the pigs are part of the reticuloendothelial system.