Respiratory health status in swine producers using respiratory protective devices

A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, betweengroup comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection. © 1993 Wiley-Liss, Inc.     

高强度超声对犬前列腺组织损伤的实验研究

目的　探讨经尿道高强度超声 (transurethralhighintensityultrasound ,TUHIU)治疗良性前列腺增生症 (benignprostatichyperplasia ,BPH)的有效性和可行性。方法　对犬前列腺进行TUHIU辐照处理 ,辐照后不同时期处死动物以观察其急性、亚急性和慢性期大体及组织病理变化。同时观察辐照前后影像学变化。结果　TUHIU辐照前前列腺部尿道平均最大宽度为 0 66± 0 12 ( x±s)cm ,辐照 3周后前列腺部尿道平均最大宽度为 2 11± 1 0 7cm ,较辐照前显著增宽。辐照后可见靶区内尿道周围腺体发生凝固性坏死 ,3 0～ 60天后坏死组织脱落尿道呈囊腔状。光、电镜下均可见腺上皮及基质细胞发生均匀性凝固性坏死。辐照后经腹B超示前列腺内部出现液性暗区 ,前列腺呈囊性改变。辐照后即刻各犬均出现短暂性尿潴留、尿频、尿线变细 ,1月后恢复正常。结论　TUHIU可破坏前列腺组织 ,明显增加前列腺部尿道宽度。     

大鼠肾移植模型技术的改进

目的 为开展器官移植的实验研究，建立了大鼠异体肾移植模型。方法使用Wistar大鼠分别作为供者和受者，采用原位低温灌洗，肾动脉带一小段主动脉，肾静脉带一小段下腔静脉、输尿管末端带一直径约为0．5cm的膀胱瓣的供者手术方式；受者主动脉与供者主动脉、受者下腔静脉与供者下腔静脉进行端侧吻合，在受者膀胱上剪去一膀胱瓣与供者相同大小的圆瓣，然后进行一层膀胱吻合。结果 第一阶段为实验探索阶段，经过半年近150次的实验摸索，克服了移植物灌洗、血管吻合、膀胱吻合等技术难关，终于建立了比较稳定的大鼠同种异体肾移植模型。第二阶段为模型成熟阶段，冷热缺血时间、血管吻合的速度以及手术时间都比第一阶段有所缩短。手术成功率为85％左右，动物死亡的原因主要为血管吻合口出血、灌洗不良、休克、血栓形成以及膀胱漏尿致弥漫性腹膜炎等。结论 此模型容易掌握，可以在条件比较简单的实验室开展，除常规显微外科器械外不需要特殊的器械或设备。     

急性软脑膜微循环障碍实验模型的研究

本文报道应用高分子右旋糖酐制成软脑膜微循环障碍的动物实验模型。软脑膜微循环障碍模型的标志;软脑膜微血管血流速度减慢,血液流态呈粒状流或絮状流,血细胞聚集。 将98只家兔分成甲、乙二组。甲组38只,静脉注射平均分子量为25万的高分子右旋糖酐,乙组60只,静脉注射平均分子量为49万的高分子右旋糖酐。实验结果发现,甲组38只家兔仅28只可复制成软脑膜微循环障碍的实验模型,模型复制成功率为73.6％;乙组60只家兔,59只可形成软脑膜微循环障碍实验模型,成功率为98.3％。本实验证明复制动物模型以49万分子量的高分子有旋糖酐为宜。 本实验模型可用于脑微循环障碍和改善脑微循环药物的研究工作。     

三种实验性IgA肾病模型的比较

目的探讨建立一种理想的IgA肾病（IgAN）动物模型方法。方法分别采用葡聚糖G200、大肠杆菌外膜蛋白和金葡菌的细胞膜20肽抗原决定簇诱导小鼠IgA肾病模型。用分子生物学和病理学方法对3组IgAN模型小鼠进行鉴定和比较。结果（1）葡聚糖组尿蛋白增高，伴有血尿；免疫荧光显示部分肾小球大量IgA沉积；光镜下肾小球系膜细胞增多，肝和脾可见弥漫性的粉染物质沉积；电镜下肾小球系膜区少量低电子密度的致密沉积物，肝和脾可见淀粉丝样物质沉积。（2）大肠杆菌外膜蛋白组尿蛋白增高，伴有血尿；免疫荧光显示肾小球有少量IgA沉积；光镜下肾小球系膜细胞轻度增多，间质炎细胞浸润明显；电镜下肾小球系膜区无电子致密沉积物。（3）金葡菌细胞膜20肽抗原决定簇组尿蛋白增高，伴有血尿；免疫荧光显示多数肾小球均可见大量IgA沉积；光镜下肾小球系膜细胞增多，伴系膜基质轻度增生；电镜下肾小球系膜区和基底膜的内皮细胞下可见高电子密度的致密沉积物。结论金葡菌细胞膜20肽抗原决定簇组诱导的IgAN模型从临床表现和病理学变化与人IgAN极其相似，是3种IgAN模型中最理想的IgAN模型。     

Assessing the Stiffness of Spinal Fusion in Animal Models

The clinical goal of spinal fusion is to reduce motion and the associated pain. Therefore, measuring motion under loading is critical. The purpose of this study was to validate four-point bending as a means to mechanically evaluate simulated fusions in dog and rabbit spines. We hypothesized that this method would be more sensitive than manual palpation and would be able to distinguish unilateral vs bilateral fusion. Spines from four mixed breed dogs and four New Zealand white rabbits were used to simulate posterolateral fusion with polymethyl methacrylate as the fusion mass. We performed manual palpation and nondestructive mechanical testing in four-point bending in four planes of motion: flexion, extension, and right and left bending. This testing protocol was used for each specimen in three fusion modes: intact, unilateral, and bilateral fusion. Under manual palpation, all intact spines were rated as not fused, and all unilateral and bilateral simulated fusions were rated as fused. In four-point bending, dog spines were significantly stiffer after unilateral fusion compared with intact in all directions. Additionally, rabbit spines were stiffer in flexion and left bending after unilateral fusion. All specimens exhibited significant differences between intact and bilateral fusion except the rabbit in extension. For unilateral vs bilateral fusion, significant differences were present for right bending in the dog model and for flexion in the rabbit. Unilateral fusion can provide enough stability to constitute a fused grade by manual palpation but may not provide structural stiffness comparable to bilateral fusion.     

Safety of, and biological and functional response to, a novel metallic implant for the management of focal full-thickness cartilage defects: Preliminary assessment in an animal model out to 1 year.

Focal full-thickness cartilage lesions of the human medial femoral condyle (MFC) can cause pain and functional impairment. Affected middle-aged patients respond unpredictably to existing treatments and knee arthroplasty may be required, prompting risk of revision. This study assesses the safety of, and biological and functional response to, a metallic resurfacing implant which may delay or obviate the need for traditional arthroplasty. The anatomic contour of the surgically exposed MFC of six adult goats was digitally mapped and an 11 mm diameter full-thickness osteochondral defect was created. An anchor-based Co-Cr resurfacing implant, matching the mapped articular contour, was implanted. Each goat's contralateral unoperated femorotibial joint was used as a control. Postoperative outcome was assessed by lameness examination, radiography, arthroscopy, synoviocentesis, necropsy, and histology up to 26 (n = 3) or 52 (n = 3) weeks. By postoperative week (POW) 4, goats demonstrated normal range of motion, no joint effusion, and only mild lameness in the operated limb. By POW 26 the animals were sound with only occasional very mild lameness. Arthroscopy at POW 14 revealed moderate synovial inflammation and a chondral membrane extending centrally across the implant surface. Radiographs at POWs 14 to 52 implied implant stability in the operated joints, as well as subchondral bone remodeling and mild exostosis formation in the operated and contralateral unoperated joints of some goats. By POW 26, histology revealed new trabecular bone abutting the implant. At POWs 26 and 52 MFC cartilage was metachromatic and intact in the operated and unoperated femorotibial joints. Proximal tibiae of some operated and unoperated limbs demonstrated limited subchondral bone remodeling and foci of articular cartilage fibrillation and thinning. The chondral membrane crossing the prosthesis possessed a metachromatic matrix containing singular and clustered chondrocytes. Our data imply the safety, biocompatibility, and functionality of the implant. Focal articular damage was documented in the operated joints at POWs 26 and 52, but lesions were much reduced over those previously reported in untreated defects. Expanded animal or preclinical human studies are justified.     

High-resolution imaging of progressive articular cartilage degeneration.

The objective of this study was to develop and verify a new technique for monitoring the progression of osteoarthritis (OA) by combining a rat model with the imaging modality optical coherence tomography (OCT). Time-sequential, in vivo, OCT imaging was performed on the left femoral condyles of 12 Wistar rats following sodium-iodoacetic acid-induced OA progression. The right femoral condyles (untreated) were also imaged and served as controls. Imaging was performed on days 0, 10, 20, 30, and 60 with an OCT system capable of acquiring images at four frames per second and an axial resolution of 5 microm. Progressive changes were analyzed using an OA scoring system. OCT successfully identified progressive cartilage degeneration as well as alteration of the cartilage/bone interface. Significant changes to both of these structures were observed in the sodium-iodoacetic acid-injected condyles. Structural changes detected with OCT were confirmed histologically. OCT in combination with a well-known model used in arthritis research represents a powerful tool for following degenerative joint disease progression in a given animal by detecting changes to the cartilage/bone interface and articular cartilage.     

胰腺分裂与慢性胰腺炎的病因学关系及发病机制

目的:探讨胰腺分裂(PD)在慢性胰腺炎病因学中的作用及其发病机制。方法:将32只犬随机分为4组(每组8只)。Ⅰ组:部分结扎背-腹胰管间的交通支。Ⅱa组:切断并结扎交通支。Ⅱb组:在背胰管注入小乳头前2mm处将其切断并结扎断端。Ⅲ组:假手术对照组,除不结扎交通支外,其余操作同上。于手术前检测各组犬血清磷脂酶(PLA2)和淀粉酶(Ams)活性及背、腹胰管基础压并在胰泌素激发后15、30、45、60和90分钟各测压一次。于术后180天再行胰胆管测压和造影并观察背、腹胰和十二指肠乳头的病理改变。结果:⑴Ⅰ、Ⅱa组和Ⅱb组术后5-80天血清PLA2和Ams活性显著升高。⑵处死时Ⅰ、Ⅱa组腹胰管和Ⅱb组背、腹胰管压力在激发后30-60分钟显著高于注药前(P<0.01);在60分钟后,前两组压力恢复到术前水平(P>0.05),而Ⅱb组仍较高(P<0.05),该组压力在90分钟后恢复正常。⑶光镜:Ⅱb组犬背、腹胰小叶间或/和胰管周围显著纤维组织增生,腺细胞结构破坏和炎细胞浸润。Ⅰ和Ⅱa组腹胰见轻度上述改变。⑷电镜:Ⅰ、Ⅱa组腹胰和Ⅱb组背、腹胰腺细胞粗面内质网脱颗粒、融合和扩张。酶原颗粒减少,线粒体肿张。Ⅰ和Ⅱa组背胰及Ⅲ组背、腹胰未见异常。结论:PD是慢性胰腺炎的病因学因素之一,其引发胰腺炎的机制是在胰液分泌的高峰期副乳头功能性梗阻。     

刺激视上核对大鼠痛阈及电针镇痛的影响

以钾离子透引起的大鼠甩尾反应为痛指标，观察了电和化学刺激视上核（ＳＯＮ）对大鼠痛阈（ＰＴ）和电针（ＥＡ）镇痛的影响。电刺激ＳＯＮ后，ＰＴ明显高于假刺激组（Ｐ＜０．０５～０．００１），电刺激ＳＯＮ后电针足三里，镇痛效应明显提高，并有明显的量效关系。电刺激ＳＯＮ的近旁部位（０．５—１ｍｍ）对ＰＴ及电针镇痛无明显影响。ＳＯＮ内注射Ｌ－谷氨酸（Ｌ－Ｇｌｕ）后痛阈和电针镇痛效应都明显对照组，也有明显的量效关