顽固性复发性气胸胸膜腔造影及硬化治疗后追踪

对32例顽固性复发性气胸患者用60%泛影葡胺进行胸膜腔造影,确定裂口后作硬化剂治疗,并作复张后胸部CT对照及手术追踪对照,取得满意效果。     

瞬间反应式二次谐波显像评价正常犬肝脏超声学造影的实验研究

目的：评价瞬间反应二次谐波显像（Ｔｒａｎｓｉｅｎｔ ｒｅｓｐｏｎｓｅ ｓｅｃｏｎｄ ｈａｒｍｏｎｅｃ ｉｍａｇｉｎｇ,ＴＲＳＨＩ）对正常肝脏声学造影的增强效果及动态变化规律,并与常规连续二次谐波显像进行对比分析。方法：６只健康杂种犬 经外周静脉注射氟碳声学造影剂,分别用常规二次谐波显像和瞬间反应式二次谐波显像扫描肝脏。造影效果评价使用视觉评分和视频密度分析。结果：常规二次谐波显像有４次Ｉ级增强、４     

Study of the Complex Between the Contrast Agent lobitridol (Xenetix®) and Elastase (PPE): A Model for Hydrophobic Site Protection in Drug-Protein Interactions

Purpose. The concept of Hydrophilic Sphere Stabilization, or Hydrophobic Shielding, has been postulated in the synthesis of biocompatible contrast agents in vascular imaging. To improve the safety of these polyiodinated agents, interactions with protein hydrophobic sites in biomacromolecules should be kept as low as possible. In order to evaluate the level of interactions with proteins, we have selected the serine proteinase Elastase, in presence of Iobitridol (Xenetix^®), as a model. Methods. The complex between Iobitridol and Pancreatic Porcine Elastase was investigated by X-ray diffraction techniques, on saturated monocrystals, using the synchrotron radiation at 0.98. Results. In contrast to Iohexol, which displays several interactions including one in the active site, Iobitridol is unable to interact directly with elastase. Only one partially occupied site is found in between two molecules of the crystal packing. Conclusions. The validation of the 'hydrophobic shielding' concept, which was at the origin of the design of the Iobitridol molecule, has been proven to be an essential feature in minimizing in vivo protein interactions.     

Cardiac effects of contrast media in MR angiography: evaluation in an experimental model of myocardial ischemia

RATIONALE AND OBJECTIVES: The authors evaluated the cardiac tolerability of paramagnetic contrast agents for magnetic resonance (MR) angiography in an in vitro model of ischemic rat heart. MATERIALS AND METHODS: The left anterior descending coronary artery was temporarily occluded in a perfused rat heart model to induce cardiac ischemia and reperfusion. A dose of 0.4 mL of gadobenate dimeglumine, of gadopentetate dimeglumine, or of D-mannitol was injected directly into the aorta both during the ischemia and during the reperfusion period. The left ventricular pressure and heart rate were recorded. RESULTS: Myocardial ischemia resulted in decreased cardiac activity, with a reduction in left ventricular pressure and heart rate. A further decrease in cardiac activity was temporarily induced by injection of contrast medium during both the ischemic and early reperfusion phases. Less marked responses were induced by a hyperosmolal solution of mannitol. CONCLUSION: These results suggest that the transient cardiac effects induced by bolus injection of paramagnetic contrast medium may be regarded as the combined effects of the osmotoxicity of the contrast medium solution and the chemotoxicity of the contrast medium molecule.     

A multiscale spatial filtering account of the White effect, simultaneous brightness contrast and grating induction

Blakeslee and McCourt ((1997) Vision Research, 37, 2849-2869) demonstrated that a multiscale array of two-dimensional difference-of-Gaussian (DOG) filters provided a simple but powerful model for explaining a number of seemingly complex features of grating induction (GI), while simultaneously encompassing salient features of brightness induction in simultaneous brightness contrast (SBC), brightness assimilation and Hermann Grid stimuli. The DOG model (and isotropic contrast models in general) cannot, however, account for another important group of brightness effects which includes the White effect (White (1979) Perception, 8, 413-416) and the demonstrations of Todorovic ((1997) Perception, 26, 379-395). This paper introduces an oriented DOG (ODOG) model which differs from the DOG model in that the filters are anisotropic and their outputs are pooled nonlinearly. The ODOG model qualitatively predicts the appearance of the test patches in the White effect, the Todorovic demonstration, GI and SBC, while quantitatively predicting the relative magnitudes of these brightness effects as measured psychophysically using brightness matching. The model also accounts for both the smooth transition in test patch brightness seen in the White effect (White & White (1985) Vision Research, 25, 1331-1335) when the relative phase of the test patch is varied relative to the inducing grating, and for the spatial variation of brightness across the test patch as measured using point-by-point brightness matching. Finally, the model predicts intensive aspects of brightness induction measured in a series of Todorovic stimuli as the arms of the test crosses are lengthened (Pessoa, Baratoff, Neumann & Todorokov (1998) Investigative Ophthalmology and Visual Science, Supplement, 39, S159), but fails in one condition. Although it is concluded that higher-level perceptual grouping factors may play a role in determining brightness in this instance, in general the psychophysical results and ODOG modeling argue strongly that the induced brightness phenomena of SBC, GI, the White effect and the Todorovic demonstration, primarily reflect early-stage cortical filtering operations in the visual system.     

Ultrasound Densitometric Analysis: Comparison Between an Online Digital Acquisition Acoustic Program and an Offline Analog Program

Videodensitometric analysis of myocardial contrast echocardiography is traditionally performed off line. Recently, an online contrast ultrasound analysis system, Acoustic Densitometry (Hewlett-Packard), was introduced. We compared pixel intensities acquired with Acoustic Densitometry to pixel intensities derived from videodensitometry. A tissue phantom was imaged in phase I using three transducer frequencies (2.5, 3.5, and 5.0 MHz). In phase II, an in vitro flowing tube model with various concentrations of Albunex® was imaged at two flow rates, 0.6 and 1.2 m/sec, and at two transducer frequencies, 2.5 and 3.5 MHz. The relationship between pixel intensities yielded by the two systems for identical ultrasound signals was determined with linear regression. Intensities derived with Acoustic Densitometry strongly correlated with those derived from the offline videodensitometry system. The intensities were related by a predictive multiplicative factor based on display characteristics of the two systems. These results suggest that semiquantitative, online perfusion analysis with Acoustic Densitometry is as sensitive as analysis offline with videodensitometry.     

Benign intracranial hypertension vs. intracranial arteriovenous malformation: A possible CT dilemma

Summary A nine-year-old boy, presenting only with signs of increased ICP, underwent computerized tomography. This examination demonstrated no abnormalities in the precontrast scan. Following C. E., it showed scattered areas of blood-like density in both hemispheres, as well as a presumedly abnormal vessel in the left occipital region and dilated vein of Galen, sinus rectus, and tentorial veins. The presumptive diagnosis of left occipital AVM was not confirmed by angiography, which also ruled out obstructions of the intracranial sinuses.The possible mechanism responsible for this atypical CT picture is briefly discussed in the light of pertinent literature. It is suggested that careful consideration should be given to the indications for angiography in similar cases, in the presence of a hypervascular aspect of the postcontrast CT scan, particularly if a considerable amount of contrast medium has been used.     

The relation of apparent brightness to contrast threshold on a photopic background :Dependence on retinal position and target size

The luminance necessary for constant apparent brightness was measured as a function of retinal eccentricity at several photopic brightness levels and compared with the corresponding increment threshold functions. Thresholds rose substantially from the fovea to the periphery, but the contrast required for constant brightness showed little change as a function of eccentricity. A change of target size had relatively little effect on the shapes of the equal brightness curves. Two contributing factors to the difference between the threshold and equal brightness curves are systematic changes in

(1) the apparent brightness at threshold

(2) the exponent of the brightness power function. A neural mechanism is proposed which accounts for the results. A comparison with known retinal ganglion cell properties leads to the conclusion that this mechanism must be located proximally to the retina.

Contrast enhancement of the cerebrospinal fluid on MRI in two cases of spirochaetal meningitis

We report two patients with meningitis due to spirochaetal infection, both of whom showed diffusely enhancing meninges around the brain and spinal cord. In addition, there was enhancement of the cerebrospinal fluid after intravenous administration of Gd-DTPA. Received: 1 March 1998/Accepted: 21 August 1999     

中西医结合治疗宫颈糜烂50例观察

目的：观察恒和坤净栓联合波姆红外光治疗宫项糜烂的疗效。方法：中西医结合组50例用恒和坤净检与波姆红外光治力仪联合治疗；对照组50例，单用波姆红外光治疗仪治疗。结果：中西医结合组痊愈率82％，对照组痊愈率40％。结论：中西医结合疗效较好，优于单用西医治疗。