心血管MR成像在缺血性心脏病中的应用

缺血性心脏病（IHD）不同阶段的病理组织学改变与病人预后和生活质量密切相关。心血管MR（CMR）成像技术具有多参数、多成像序列,能对IHD进行早期诊断,评价微血管阻塞、心肌内出血、瘢痕心肌和舒张末期心室壁厚度,通过对急慢性心肌梗死进行早期诊断和远期风险评估,为病人的早期治疗及降低预后风险提供信息。就CMR在急慢性IHD心肌组织特征、风险评估和病人远期预后方面的应用予以综述。     

Intramammary extension of breast cancer: Diagnosis with MR mammography

Purpose  Intramammary extension of breast cancer was investigated using contrast-enhanced magnetic resonance (MR) imaging by comparing MR findings with the histopathology of specimens used for pretreatment planning. Materials and Methods  Thirty-nine breast cancers were examined. The dynamic protocol was performed with a 2- or 3-dimensional fast spin echo sequence (1.5 T), once before and 2-5 times immediately after Gd-DTPA administration with an original fat suppression technique. The findings were correlated with the histopathology. Results  All main tumors showed early enhancement. All with direct invasion histopathologically showed spicular enhancement. The four patients who had separate nodular enhancement showed satellite lesions histopathologically. Three-typed MR findings were found to be indicative of an intraductal component. Conclusion  Various forms of breast cancer were reliably demonstrated using MR imaging. MR imaging could be useful for the pretreatment planning for patients with breast cancer.     

The effects of strychnine on recently acquired and reactivated passive avoidance memories

Rats were trained on passive avoidance (PA) or were given equivalent handling and footshocks (FS) prior to injection with either strychnine (1 mg/kg IP) or saline. Twenty-four hr after injection, rats in the PA-strychnine condition took significantly more trials to learn active avoidance than did animals in any of the other conditions. In Experiment 2, the interval between PA training and the strychnine treatment was extended to 72 hr. Using this interval, retarded active avoidance acquisition occurred only when the memory of PA training was reactivated just prior to the strychnine injection. Results were interpreted as indicating that strychnine enhanced the memory of the PA training requirements, thus interfering with the acquisition of active avoidance. However, this enhancement did not appear to depend on the influence of strychnine on the consolidation of the PA memory.     

一种线性滤波算子在医学扫描图像中的应用

目的：解决传统的二维锐化增强算子不能很好解决扫描医用胶片图像不同区域不同模糊程度的问题。材料和方法：本文根据扫描仪成像系统的特点，提出了一维滤波进行处理。通过不同区域不同长度滤波算子的处理。保证了处理后的图像整体一致清晰。结果：本方法跟二维滤波相比运算量大幅下降，满足大尺寸扫描图像实时处理的要求。结论：试验结果表明，该一维算子稳健高效，提高了图像的清晰度、对比度，让医生能够更准确的诊断。     

Contrast enhancement in a Hermann grid with variable figure-ground ratio

Summary Psychophysical experiments on contrast vision were made using a modified Hermann grid which was graded in two directions. This pattern was composed of intersecting (IG) and intersected stripes (ID) representing 15 shades of a gray scale, and was viewed against 5 uniform backgrounds (BGD) ranging from white to black. Illusory light and dark patches at intersections were essentially limited to IG's that ranged in reflectance between BGD and ID. The illusion was most distinct when the contrast ratio between IG and BGD was minimum, while that between IG and ID was maximum; it was much reduced on intersections formed by equireflectant stripes, such as those in the original Hermann grids. Brighter responses were evoked by a white BGD and darker responses by a black BGD. Gray BGD's elicited both kinds of responses. The contrast effects were more pronounced for vertical and horizontal than for diagonal grid orientation. An optimum grid was devised that shows maximum brightness changes at almost every intersection, even when fixated foveally. The observations are interpreted in terms of Baumgartner's receptive field hypothesis.This work was supported (in part) by PHS Grant EY00227 from the National Eye Institute (to Dr. C.L. Schepens) and by a grant from the John A. Hartford Foundation, Inc. (to Dr. H.L. Teuber).JL worked under the summer student program of Chelsea High School     

增强心室晚电位信号的自适应滤波方法

介绍了一种基于自适应滤波的心室晚电位信号增强方法，这种自适应滤波器仅有一个信号电极而无需参考电极，实验结果表明这种自适应滤波方法可有效提高心室晚电位信号的信噪比。     

Early childhood diagnosis of acoustic neuromas in presymptomatic individuals at risk for neurofibromatosis 2

We report on a family in which individuals at risk for NF 2 were investigated with the use of gadolinium-enhanced MRI. This technique has allowed the diagnosis of small ( < 8 mm) acoustic neuromas in two asymptomatic children (age 7 and 11), one of whom had normal audiometric and brainstem-evoked response testing. To our knowledge these are the youngest asymptomatic patients in whom the diagnosis of NF 2 has been demonstrated. It is possible that acoustic neuromas develop at an early age more commonly than recognized previously. The early diagnosis of acoustic neuromas with the use of gadolinium-enhanced MRI may lead to better outcome following surgery. This technique will provide the opportunity to better determine the natural course of this disease.     

Induction of late cutaneous reaction by kallikrein injection: comparison with allergic-like late response to compound 48/80

Although IgE antibody is able to provoke a late cutaneous allergic response (LCAR), the mechanism of its development is not clear. It seems to involve vasoactive and clotting mediators released from mast cells and basophils. Substances biologically similar to plasma kallikrein (KK), a Hageman factor activator, have been shown to be released by basophils in the course of an IgE-dependent reaction. Because compound 48/80 induces LCAR-like responses in the skin, we compared the ability of tissue KK and compound 48/80 to induce late cutaneous reactions (LCRs). All 40 test subjects showed an immediate wheal and flare reaction (WF) after both KK and 48/80. The WF was followed by an LCR characterized by diffuse edema, pain, and erythema in 36 of 40 subjects with 48/80 and 26 of 40 with KK. The LCRs evoked by the two agents did not differ in their appearance or in their time of development. These reactions increased until the 5 hr mark, began to decrease at the 10 hr mark, and were gone after 24 hr. Histologic study showed edema and a mixed cell infiltration with fibrin deposition. Challenge of the original injection site and a new site after 1 or 2 wk showed a local refractory state lasting 2 wk. Prednisone almost totally suppressed the LCRs induced by both KK and 48/80.     

Profound effects of combining choline and piracetam on memory enhancement and cholinergic function in aged rats

In an attempt to gain some insight into possible approaches to reducing age-related memory disturbances, aged Fischer 344 rats were administered either vehicle, choline, piracetam or a combination of choline or piracetam. Animals in each group were tested behaviorally for retention of a one trial passive avoidance task, and biochemically to determine changes in choline and acetylcholine levels in hippocampus, cortex and striatum. Previous research has shown that rats of this strain suffer severe age-related deficits on this passive avoidance task and that memory disturbances are at least partially responsible. Those subjects given only choline (100 mg/kg) did not differ on the behavioral task from control animals administered vehicle. Rats given piracetam (100 mg/kg) performed slightly better than control rats (p<0.05), but rats given the piracetam/choline combination (100 mg/kg of each) exhibited retention scores several times better than those given piracetam alone. In a second study, it was shown that twice the dose of piracetam (200 mg/kg) or choline (200 mg/kg) alone, still did not enhance retention nearly as well as when piracetam and choline (100 mg/kg of each) were administered together. Further, repeated administration (1 week) of the piracetam/choline combination was superior to acute injections. Regional determinations of choline and acetylcholine revealed interesting differences between treatments and brain area. Although choline administration raised choline content about 50% in striatum and cortex, changes in acetylcholine levels were much more subtle (only 6–10%). No significant changes following choline administration were observed in the hippocampus. However, piracetam alone markedly increased choline content in hippocampus (88%) and tended to decrease acetylcholine levels (19%). No measurable changes in striatum or cortex were observed following piracetam administration. The combination of choline and piracetam did not potentiate the effects seen with either drug alone, and in certain cases the effects were much less pronounced under the drug combination. These data were discussed as they relate to possible effects of choline and piracetam on cholinergic transmission and other neuronal function, and how these effects may reduce specific memory disturbances in aged subjects. The results of these studies demonstrate that the effects of combining choline and piracetam are quite different than those obtained with either drug alone and support the notion that in order to achieve substantial efficacy in aged subjects it may be necessary to reduce multiple, interactive neurochemical dysfunctions in the brain, or affect activity in more than one parameter of a deficient metabolic pathway.