Up-regulation of the hyaluronate receptor CD44 in canine distemper demyelinated plaques

CD44 antigen (CD44), the principle cell surface receptor for hyaluronate, is up-regulated in the human demyelinating disease multiple sclerosis on fibrous astrocytes. As astrocytes are the main target cell of canine distemper virus (CDV), the consequences of a CDV infection on the CD44 expression and distribution in brains with spontaneous demyelinating canine distemper encephalitis (CDE) were of interest. Thirteen acute, 35 subacute, and 11 chronic plaques of nine dogs with immunohistologically confirmed CDE and brains of control dogs were included in the study. For light microscopy, 5-μm-thick serial sections were stained with H & E and incubated with monoclonal antibodies (mAbs) against CD44 and canine distemper virus nucleoprotein and polyclonal antibodies (pAbs) against glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP). For immunoelectron microscopy, 90-nm-thick sections were double stained with anti-GFAP and anti-CD44 mAbs to specify CD44-expressing structures. In controls, CD44 was diffusely distributed in the white matter and single meningeal cells exhibited a marginal expression of the antigen. In acute and more prominently in subacute demyelinating encephalitis, there was a plaque-associated up-regulation of CD44 which paralleled GFAP. In chronic demyelinating lesions, a reduction of CD44 associated with a loss of GFAP-positive astrocytes was noted. Additionally, in chronic plaques, CD44 was expressed on the cell membrane of perivascular mononuclear cells. Immunoelectron microscopically, in controls, CD44 was rarely demonstrated on astrocytic cell processes. In contrast, in brains with CDE CD44 was found on the cell membrane of broadened astrocytic cell processes. In summary, CD44 is up-regulated on astrocytes in the early phase of CDE and seems to represent a marker for the activation of immune cells in the late phase of the infection. Received: 4 March 1999 / Revised: 9 June 1999 / Accepted: 28 June 1999     

生物血管异种移植的初步研究

目的为了寻求一种新的小口径血管代用品,建立异种移植的动物实验模型,以观察异种移植物的安全性、可靠性、通畅性及组织学改变。方法共采用17只杂种雌性犬,实验组10只,植入经环氧化物处理的猪血管移植物;对照组7只,植入人造血管。手术方法为右侧股动静脉瘘。术后通过超声和血管造影方法来观察移植血管的通畅性,并在术后3月将移植物取出,进行病理学检查,观察移植前后移植物的组织学改变。结果术后第一周、二周行Doppler超声检查结果,两组动静脉瘘均通畅,2周内血管通畅率为100%。术后3个月动脉造影检查后,生物血管组(PG)通畅5只,通畅率62.5%,e-PTFE组通畅4只,通畅率66.7%。两组数据统计学处理,差异无显著性(P>0.05)。术后3月对移植物取材,进行光镜及扫描电镜病理学检查,通畅的生物血管吻合口无狭窄,吻合部位有新的内膜覆盖,周围组织无钙化,有新生的内皮细胞覆盖。结论经环氧化物处理的猪的血管移植物(PG)生物血管作为异种移植物,生物相容性好,具有一定的可行性。     

The incisal edge bracket for gold chain attachment to unerupted teeth.

Abstract

A method is described to reduce the morbidity involved in direct bonding of unerupted incisors by use of a precontoured bracket. Increased bracket stability during placement is an additional advantage.     

计算机辅助下低温手术建立三足犬股骨头坏死模型的初步报告

目的建立能模拟人股骨头坏死（osteoneerosis of femoral head，ONFH）病理生理过程的实验动物模型，旨在实验动物水平评价其治疗价值。方法在计算机辅助设计下，采用FLUENT6．2软件对探针置入股骨头后内部温度场分布进行三维有限元分析，设计出可最大化ONFH面积，最小化周围组织损伤的低温手术过程，即在0．5MPa加压液氮下，冷冻6．5min，复温5min至2℃，再次冷冻6．5min。采用上海交通大学生命学院等自主研发的液氮低温冷冻系统，按模拟得到的最佳手术方案建立10只三足犬ONFH动物模型，同时2只假冷冻组作为对照组，通过影像学和病理组织学观察，以确认模型的合理性。结果模拟结果与实验中测股骨头边界的降温曲线基本吻合。于1周后病理组织学观察，实验组股骨头髓腔内有核细胞死亡，局部血管破裂。对照组未见异常改变。实验组余9只继续观察，其中超过3个月的5只X线片和MRI均显示股骨头轻度变形，囊性变，股骨头内部密度不均，呈典型的Ficat Ⅲ期改变，其余4只动物仍在继续观察中。对照组无异常改变。结论应用计算机辅助下的低温手术可建立进展至股骨头塌陷的三足犬ONFH模型。     

‘Putting our heads together’: insights into genomic conservation between human and canine intracranial tumors

Numerous attributes render the domestic dog a highly pertinent model for cancer-associated gene discovery. We performed microarray-based comparative genomic hybridization analysis of 60 spontaneous canine intracranial tumors to examine the degree to which dog and human patients exhibit aberrations of ancestrally related chromosome regions, consistent with a shared pathogenesis. Canine gliomas and meningiomas both demonstrated chromosome copy number aberrations (CNAs) that share evolutionarily conserved synteny with those previously reported in their human counterpart. Interestingly, however, genomic imbalances orthologous to some of the hallmark aberrations of human intracranial tumors, including chromosome 22/NF2 deletions in meningiomas and chromosome 1p/19q deletions in oligodendrogliomas, were not major events in the dog. Furthermore, and perhaps most significantly, we identified highly recurrent CNAs in canine intracranial tumors for which the human orthologue has been reported previously at low frequency but which have not, thus far, been associated intimately with the pathogenesis of the tumor. The presence of orthologous CNAs in canine and human intracranial cancers is strongly suggestive of their biological significance in tumor development and/or progression. Moreover, the limited genetic heterogenity within purebred dog populations, coupled with the contrasting organization of the dog and human karyotypes, offers tremendous opportunities for refining evolutionarily conserved regions of tumor-associated genomic imbalance that may harbor novel candidate genes involved in their pathogenesis. A comparative approach to the study of canine and human intracranial tumors may therefore provide new insights into their genetic etiology, towards development of more sophisticated molecular subclassification and tailored therapies in both species.     

犬颈总动脉实验性虹吸段血管模型的建立

目的 探讨截取一侧颈总动脉节段与另一侧颈总动脉端端吻合建立颅底段颈内动脉（虹吸段）血管模型的可行性.方法 对8只成年家犬应用显微外科技术,将玻璃管制成“S”形,一侧颈总动脉（CCA）作为母体动脉,截取另一侧颈总动脉节段穿过玻璃管模型与对侧CCA端端吻合.2周后作血管造影（CTA/DSA）证实模型内血流通畅.结果 8只犬均成功地建成颅底段颈内动脉（虹吸段）血管模型.结论 应用犬一侧颈总动脉节段与另一侧颈总动脉端端吻合建立颅底段颈内动脉（虹吸段）血管模型切实可行.     

Vascular alterations in the canine kidney following obstruction of the urinary tract

Summary Changes in the vasculature of the canine kidney following four weeks obstruction of the ureter via double ligature is described on the basis of SEM investigation. Three significant alterations were observed: 1) A two-thirds reduction in the depth of the renal cortex as compared to controls. 2) Rarification of the entire cortical capillary bed. 3) Reduction in both the number and diameter of the glomeruli. The rarification of the post-glomerular capillaries is interpreted to be a pressure atrophy, whereas the reduction in the number of renal glomeruli and the concommitant diminuation of their capillary loops is thought to represent a functional atrophy.     

Assessment of dσ*/dtmax, a Load Independent Index of Contractility, in the Canine

The search for a load-independent index of myocardial contractility has been a focus for nearly 100 years. Nearly all of the parameters developed have yielded insight into cardiac function but their clinical utility has been limited. A new index, dσ*/dt _max, has been proposed to be useful in the clinic. This parameter is expressed as the maximum time rate of change of the pressure normalized circumferential wall stress (σ* = σ _θ /P, where σ _θ is circumferential wall stress and P is pressure) for a thick walled sphere model of the left ventricle (LV). This definition for a contractility index renders dσ*/dt _max dependent only on LV wall volume (V _m) and maximum time rate of change of the ventricular volume, dV/dt _max. The index dσ*/dt _max has been studied in patients with echocardiogram-derived volume, but up until this point its characteristics in canines have remained unknown. Validating this index in the canine will allow for a more intensive and wide-range investigation of the index that is not available with humans. The purpose of this study was to validate dσ*/dt _max as a load-independent measure of contractility in the canine heart with the hope that it was a noninvasive assessment of contractile function. To assess the load independence of dσ*/dt _max, the index was estimated over a range of preloads (end diastolic volume, EDV) during a vena caval occlusion (VCO). The study was conducted in five canines under various pacing modes [right atrial (RA), right ventricular (RV), left ventricular (LV), and biventricular (BV)] at rates of 90 or 100, and 160 bpm. The animals’ ventricular volume measurements were assessed by conductance catheter, calibrated with echocardiography. A 50 Hz filter was applied to the volume signal before differentiation to obtain dV/dt _max. Echocardiography was used to calculate left ventricle mass and V _m. In eight of ten cases, dσ*/dt _max was significantly correlated with decreasing EDV (p < 0.05). There was also a significant correlation between dσ*/dt _max and dP/dt _max. With a strong correlation between the values of dσ*/dt _max, dP/dt _max, and EDV in all five subjects, dσ*/dt _max is not load independent in the canine heart when preload is altered by a VCO. Further evaluation of this index is required to delineate the situations where dσ*/dt _max can be accurately applied.     

心力衰竭犬心房结构重构的实验研究

目的观察右室快速起搏建立心力衰竭犬模型的效果,探讨心房结构重构在心力衰竭与心房颤动形成过程中的作用机制。方法13只犬随机分为起搏组(n=7)和假手术组(n=6),于左、右心房各缝植4对电极,起搏电极缝植在右室心尖,连接实验用VOO型起搏器,快速心室起搏(220次/分)6周,建立心力衰竭犬模型,分别于起搏前、起搏6周后,应用经食管超声心动图测量左房收缩末容积;采用双平面Simpson法测量左室舒张期末和收缩期末容积,得出左室射血分数和心输出量,并应用光镜和电镜观察心房肌的超微结构。结果①假手术组术前和术后心脏各参数无明显变化。②起搏6周后,起搏组与假手术组比较,左房收缩末容积显著增大[(23.2±4.1)vs(13.5±1.9)cm3,P<0.01],左室舒张末期容积显著增大[(56.2±11.3)vs(33.7±9.6)cm3,P<0.01],左室收缩末期容积显著增大[(38.4±8.4)vs(14.5±8.6)cm3,P<0.01],射血分数显著降低[(31.4±10.2)vs(56.8±4.5)%,P<0.01],心输出量著降低[(1.2±0.5)vs(2.8±1.6)L/min,P<0.01]。③病理学结果显示起搏犬心房肌细胞变性、肌纤维溶解、线粒体肿胀以及间质胶原增生、水肿。结论心房结构重构是心力衰竭犬发生心房颤动的重要原因。     

组织型纤溶酶原激活剂基因导入犬血管壁预防血管成形术后再狭窄

目的：组织型纤溶酶原激活剂（ｔ－ＰＡ）基因治疗，为防治血栓性疾病提供了一个可能全新的方法与前景。探索ｔ－ＰＡ基因转移至犬血管壁后基因表达持续的时限以及预防血管成行术后再狭窄的价值。方法：１８条家犬，其中对照组６条，另１２条在形成再狭窄模型时随机分为３０天、６０天和９０天３个观察亚组，每组４条犬，并用多孔球囊输注导管将携带ｔ－ＰＡ基因的逆转录病毒载体直接高压注入冠状动脉及股动脉壁。结果：经过３０天、６０天和９０天不同时间的观察，发现在脱氧核糖核酸（ＤＮＡ）水平（原位杂交、ＤＮＡ印迹）、转录水平［（信使核糖核酸（ｍＲＮＡ）点杂交］及产物水平（免疫组化）等方面均证实ｔ－ＰＡ基因的存在和活性产物表达，而且发现再狭窄组３个月时基因治疗组比对照组的百分狭窄面积小２２．２％。结论：ｔ－ＰＡ基因治疗有一定的预防血管成形术后再狭窄的作用