Animal models to investigate drug effects on coronary physiology

Coronary blood flow is regulated by local intrinsic mechanisms according to the oxygen need of the myocardium, but the coronary circulation is also modulated by nervous, humoral, and extravascular influences. Therefore, any method used to study drug effects on the coronary circulation must take into account not only the direct effects of the drug but also any secondary drug effects that might indirectly influence the coronary vasculature. The simplest methods involve the use of isolated vessels. With these methods, the environment of the vessel can be precisely controlled, although usually only vessels larger than true resistance vessels can be studied. Isolated heart models have also been successfully employed, and in these models, effects of the drug on the myocardium must be considered. More complex models include in vivo anesthetized animal techniques with intracoronary drug administratiorl. With these models, drug effects on the coronary circulation as well as on other cardiac variables can be examined. The use of conscious, instrumented animals perhaps provides the most physiologic preparation and is very useful, particularly if intracoronary administration of drugs is employed.     

多层螺旋CT血管成像在椎基底动脉供血不足病因诊断中的应用

目的探讨多层螺旋CT血管成像(MSCTA)在诊断椎-基底动脉供血不足中的临床价值。方法对临床确诊VBI患者32例,进行颅脑CTA、颈部血管彩超、经颅多普勒超声(TCD)检查。结果VBI患者TCD检查阳性率为68.8%,颈部血管彩超阳性率为56.3%,颅脑CTA阳性率为90.6%。结论在VBI诊断方面,CTA检查较颈部血管彩超、TCD检查有明显的优势,提示CTA可以作为诊断VBI的首选方法之一,值得临床推广。     

Ferritin is a component of the neuritic (senile) plaque in Alzheimer dementia

Summary A strong immunoreactivity for ferritin was observed in the neuritic (senile) plaques in Alzheimer's disease hippocampus. The ferritin accumulation was almost exclusively associated with the microglia, which appeared to have proliferated greatly. These cells were also positive for HLA-DR, a putative marker for reactive microglia. In contrast, in the diffuse plaques, which were without neuritic pathology, the ferritin-stained microglia appeared to be normal. Microglia were seen frequently in contact with neurons undergoing neurofibrillary changes but only the tangles in the extracellular space were ferritin positive. No ferritin was detected, by Western blots, in paired helical filaments isolated from Alzheimer's disease brain, suggesting that ferritin was most likely weakly associated with and was not a constituent of these fibrils. No correlation between increased ferritin/microglia activity and blood-brain barrier leakage was detected. Ferritin, an iron-storage protein, might have a role in the formation of amyloid through the action of free radicals generated during the release of iron from the ferritin molecule. Alternatively, the ferritin/microglia system might be secondarily involved in the removal and processing of the amyloid.Supported in part by the New York State Office of Mental Retardation and Developmental Disabilities and National Institutes of Health grants NS18105, AG05892 and AG04220. H. L. was funded by a grant from the Ministry for Science and Research, Austria, J. G. J. and J. F. were funded by the Council for Tobacco Research. Parts of this paper have been reported at the 9th International Conference on Proteins of Iron Transport and Storage, Brisbane, Australia, June 1989 and at the 2nd International Conference on Aluminium and Health, Orlando, Fla, USA, December 1989     

螺旋断层放射治疗腹部肿瘤治疗误差分析

目的探讨螺旋断层放射治疗腹部肿瘤的物理学选择参数和MVCT影像引导下的治疗误差。方法采用螺旋断层治疗20例上腹部肿瘤患者，照射野宽度（field width，FW）为2．5cm，螺距比（pitch）选择0．3，调制因子（modulation factor，MF）为2．5；每次治疗前实行靶区MVCT扫描并与治疗计划靶区进行自动配准后再实现剂量靶区的手动调节，获得治疗误差及分布规律。结果治疗误差最小值和最大值在x、y和z轴分别为：（1．205±0．207）mm和（6．496±2．165）mm；（2．600±0．671）mm和（9．0075±1．5017）mm；（0．880±0．188）mm和（5．151±1．821）mm。结论影像引导确实提高了肿瘤治疗精度和准确性，同时为正确设定上腹部肿瘤计划靶区提供了依据。     

Paired helical filaments associated with Alzheimer disease are readily soluble structures

Considerable controversy exists concerning the origin and composition of Alzheimer neurofibrillary tangles (ANT) and of paired helical filaments (PHF), the abnormal cytoplasmic fibers which ultrastructurally are the major components of ANT. Thus far, the unusual solubility properties of PHF have hindered the analysis of ANT. A new procedure is presented for isolating purified PHF which are soluble in the presence of sodium dodecyl sulfate. The purification protocol involves differential and rate zonal centrifugation, treatment with the detergents sarcosyl and sulfobetain 3-14, and sonication. The isolated PHF from Alzheimer disease/senile dementia of the Alzheimer type (7 cases) and Down's syndrome (one case) have been characterized structurally by negative-stain electron microscopy, biochemically by PAGE, and immunologically by both the ELISA technique and Western blot analysis using a monoclonal antibody prepared against ANT. Distinct polypeptides were shown to be associated with this structure and not seen in preparations from young and age-matched normal brains.     

Stereotactic Image-Guided Intensity Modulated Radiotherapy Using the HI-ART II Helical Tomotherapy System

The highly integrated adaptive radiation therapy (HI-ART II) helical tomotherapy unit is a new radiotherapy machine designed to achieve highly precise and accurate treatments at all body sites. The precision and accuracy of the HI-ART II is similar to that provided by stereotactic radiosurgery systems, hence the historical distinction between external beam radiotherapy and stereotactic procedures based on differing precision requirements is removed for this device. The objectives of this work are: (1) to describe stereotactic helical tomotherapy processes (SRS, SBRT); (2) to show that the precision and accuracy of the HI-ART meet the requirements defined for SRS and SBRT; and (3) to describe the clinical implementation of a stereotactic image-guided intensity modulated radiation therapy (IG-IMRT) system that incorporates optical motion management.     

16层螺旋CT的图像后处理技术在膝关节骨损伤中的应用

目的:探讨螺旋CT及其图像后处理功能在膝关节骨折中的临床应用价值。材料与方法:对52例膝关节损伤患者进行多层螺旋CT扫描,重建膝关节三维图像。结果:MPR和VR技术满意地显示出三维重建图像。结论:多层CT三维重建能直观、立体、全面的显示膝关节骨折,具有很高的临床应用价值。     

螺旋CT增强扫描在胆囊癌诊断中的价值

目的探讨螺旋CT多期增强扫描在胆囊癌诊断中的作用。方法对23例经病理证实的胆囊癌患者的多期螺旋CT表现进行回顾性分析。结果胆囊癌主要CT表现为胆囊壁的不规则增厚和结节状突起以及胆囊内的肿块，增强扫描强化明显且持续时间长。结论螺旋CT多期增强扫描在胆囊癌的定性诊断及了解胆囊癌的侵犯范围上具有重要作用。