[Infection related fertility disorders in Swiss pig breeding farms at the end of the postweaning multisystemic wasting syndrome (PMWS) epizooty]. / Infektionsbedingte Fruchtbarkeitsstörungen in schweizerischen Schweinezuchtbetrieben am Ende der «Postweaning Multisystemic Wasting Syndrome¼ (PMWS)-Epizootie.

Porcine Circovirus type 2 (PCV2) is able to induce reproductive failures. 286 fetuses from 113 sows of 59 farms with increased reproductive disorders which included abortions, mummies, stillborn and weak born piglets were studied six years after the beginning of the epizooty of postweaning multisystemic wasting syndrome (PMWS) in Switzerland. 14 % of the cases were bacterial infections based on histological signs of inflammation and pathogen isolation. 12 % further cases showed inflammatory reactions by histology without pathogen identification. PCV2 was identified in only 4 % of cases by immunohistochemistry (IHC). Thus, PCV2 infections are of minor importance in respect to pig reproductive failures in Switzerland. Porcine parvovirus (PPV) infections were found in 3 % of the cases and seem to occur more infrequently compared to former findings. Hitherto, Enteroviruses/Teschovirus were marginally studied in etiologically undefined cases with a prevalence of 11 %. To our knowledge this is the first identification of Enteroviruses/Teschovirus in fetal tissue from reproductive failures in Switzerland. The etiology remained unclear in more than 50 % of all cases in spite of modern diagnostic methods.

Siloxane and silsesquioxane molecules--precursors for silicate materials.

Preparation of ceramics by sol-gel method has been known for many years, but recently it has been developed as a method for the synthesis of nanostructural ceramic materials. Hydrolytic polycondensation of simple molecules [e.g. most widely used tetraethoxysilane (TEOS)] leads to xerogel materials that can contain macromolecules of distinct random, ladder and cage or partial cage structure. In order to obtain well-defined silsesquioxanes it is preferred to start the process with more complex molecules, bringing in a specific framework that can govern the structure of the product. In the presented work alkoxy derivatives of cyclosiloxanes and polysiloxanes as well as a hydride derivative of octahedral silsequioxane (T(8)(H)) were applied as precursors in the process of hydrolytic polycondensation. Depending on the reaction conditions, silsesquioxane macromolecules or silica material of ordered structure were obtained. We have prepared mesoporous organiosilica materials without using any template or surfactant whatsoever. The meso-pores are created due to the unique structure of initial oligosiloxane or silsequioxane molecules and the specific interactions in the used catalyst/solvent system. In the case of octasilsesquioxane precursor, the condensation process gives directly mesoporous silica material. Dried polysilsesquioxanes were heated at the temperature of 600°C in argon or air atmosphere (pyrolysis or ceramization). In the atmosphere of argon SiC(x)O(y) glass materials were obtained.

Do stroke patients with normal carotid arteries require TEE for exclusion of relevant aortic plaques?

OBJECTIVES: This study investigated (a) the hypothesis that stroke patients with aortic atheroma would show comparable atherosclerotic changes in the carotid arteries, which are easily accessible for ultrasound evaluation and (b) the possibility of carotid duplex sonography as a replacement for transoesophageal echocardiography (TEE) for the exclusion or prediction of relevant aortic plaques. METHODS: In 301 consecutive patients (mean age 62 years) with acute cerebral ischaemia, two dimensional ultrasound measurements were taken of common carotid artery intima media thickness (IMT) and maximal plaque area (PA) and the local degree of internal carotid artery (ICA) stenosis were determined. Maximal aortic wall thickness (AWT) was assessed by TEE. RESULTS: An IMT < or =0.9 mm yielded a negative predictive value (NPV) of 95.8% for exclusion of aortic atheromas > or =4 mm and an NPV of 100% for the exclusion of aortic thrombi. However, positive predictive value of IMT >0.9 mm was low (29.6%), increasing only slightly in the presence of carotid plaques (33%). Incidence of aortic thrombi was significantly higher with > or =50% compared with <50% ICA stenosis (11.3% v 3.9%, respectively). IMT and PA correlated moderately with AWT (r = 0.47, r = 0.53, respectively; p<0.001). Systolic blood pressure, coronary heart disease and peripheral artery disease, increased IMT, and ICA stenosis > or =50% were independently related to AWT > or =4 mm. CONCLUSIONS: A high NPV of normal carotid ultrasound does not support routine TEE for the exclusion of complex aortic plaques as a high risk source of cerebral embolism. However, in patients with carotid atherosclerosis, particularly in those with ICA stenosis > or =50%, TEE should be performed to exclude an additional high risk source for stroke.

Improved 3-D-echocardiographic endocardial border delineation using the contrast agent FS069 (Optison) transesophageal studies in a porcine model.

3-D echocardiography has the potential for quantitative assessment of regional wall motion. However, the 3-D procedures used to date do not provide the same spatial and temporal resolution as 2-D echocardiography, which results in problems with border delineation of the endocardium. There are, as yet, few studies testing if the use of contrast agent can improve endocardial definition in the 3-D data set. FS069 (Optison) was used for the first time for this purpose in the present study. A total of 12 mechanically-ventilated pigs were examined by transesophageal 3-D echocardiography, 1. using fundamental imaging and 2. following left-atrial injection of FS069 (Optison). The left ventricle was analyzed using an 18-segment model. Score with the value 0 (not visible), 1 (moderately visible) and 2 (well defined) were used to rate endocardial definition. All segments were assessed both end-diastolic and end-systolic. Various LV regions were examined by grouping segments (anterior/lateral/inferior and basal/mid-ventricular/apical). Using the contrast agent, the proportion of nonvisible segments fell diastolic from 40 (18.5%) to 15 (6.9%), and systolic from 26 (12.0%) to 11 (5.1%). The proportion of well defined segments increased diastolic from 62 (28.7%) to 108 (50%) and systolic from 73 (33.8%) to 123 (56.9%). The mean visibility score increased diastolic from 1.10 +/- 0.68 to 1.43 +/- 0.62 (p < 0.001), systolic from 1.22 +/- 0.64 to 1.52 +/- 0.59 (p < 0.001). The benefit was greatest in regions where the visibility score was lowest without contrast: in the area of the lateral wall and systolic near the apex. In conclusion, the use of FS069 (Optison) results in significantly better endocardial delineation in the 3-D data set. This could be important in future for the 3-D echocardiographic assessment of regional wall motion.

Dynamic changes of atrial septal defect area: new insights by three-dimensional volume-rendered echocardiography with high temporal resolution.

AIMS: The purpose of this study was: (i) to record dynamic changes in the area of atrial septal defects (ASD) during a cardiac cycle, and (ii) to investigate factors which influence ASD dynamics. Implementation of new software modifications allowed the frame rate to be doubled, as compared to usual techniques. METHODS AND RESULTS: Twenty patients were examined using transoesophageal three-dimensional (3D) echocardiography. In 10 patients the 3D dataset was recorded with a frame rate of 25Hz, in another 10 patients with a frame rate of 50Hz. The ASD area was planimetried for each picture and the changes analysed over time. The ASD area showed dynamic changes during the cardiac cycle with an end-systolic maximum and end-diastolic minimum. The influence of the various phases of the cardiac cycle on area changes could be differentiated especially at higher temporal resolution. The relative change in ASD area showed no significant relationship to Q(p)/Q(s)ratio, mean ASD size or heart rate. By contrast, there was a slight inverse correlation to age (r=-0.t45,P <0.05). CONCLUSION: Transoesophageal 3D volume-rendered echocardiography permits quantitative recording of ASD dynamics. The ASD area changes are influenced especially by the various phases of the cardiac cycle.

Identification of silicooxygen rings in SiO2 based on IR spectra.

In this work application of IR spectra for the determination of silcooxygen ring types in framework silicates structures has been presented. Results of the spectra interpretation for cyclosilicates ('isolated' silicooxygen rings) have been adopted for the spectra of highly polymerized SiO2 structures. In such structures, silicooxygen rings are interconnected. In this work, spectra of three basic polymorphous SiO2 types, i.e. cristobalite, tridymite quartz (in various temperature forms) and v-SiO2 are discussed. It has been shown that identification of rings is possible after precise analysis of the spectra preceded by mathematical decomposition.

Myxoma of the mitral valve: diagnosis by 2-dimensional and 3-dimensional echocardiography.

In this report we describe a 39-year-old patient who had left-sided hemiparesis. In search of a source of embolism, we performed transthoracic echocardiography, which did not show any abnormalities. Transesophageal echocardiography revealed a small tumor of the posterior mitral leaflet. Three-dimensional transesophageal echocardiography was subsequently performed and demonstrated more accurate information about the size, the morphology, and the attachment point of the tumor. Furthermore, the reconstruction provided excellent spatial visualization of the pathomorphology of the mitral valve and was a useful addition for optimal preoperative diagnostic management. The tumor was excised, and histologic examination confirmed the myxomatous character of the tumor. Mitral valve myxomas are rare. This is the first case reported of a mitral valve myxoma being visualized by 3D echocardiography.

[Diagnostic value of various echo- and Doppler echocardiography methods in quantifying mitral valve stenosis]. / Diagnostischer Stellenwert verschiedener echo- und Doppler-echokardiographischer Methoden in der Quantifizierung von Mitralklappenstenosen.

UNLABELLED: Two-dimensional and Doppler echocardiography have been widely used for noninvasive determination of valve area in patients with mitral stenosis. Recent studies have indicated that the Doppler-echocardiographic pressure half-time method (PHT) does not accurately predict mitral orifice area (MOA). Therefore, applications of the continuity equation and the Gorlin formula have been used additionally to the PHT for Doppler-echocardiographic assessment of MOA. In a prospective study of 34 patients MOA determined by two-dimensional and Doppler echocardiography was compared with MOA measured by cardiac catheterization (range 0.40 to 1.90 cm2, mean 1.08 +/- 0.37 cm2). There was a moderate correlation between two-dimensional echocardiographic and invasive measurements (r = 0.65, SEE = 0.20 cm2). MOA calculated by the PHT showed only poor correlation with cardiac catheterization (r = 0.38 SEE = 0.37 cm2). We found better correlations for the continuity equation (r = 0.73, SEE = 0.35 cm2) and Doppler-echocardiographic application of the Gorlin formula (r = 0.81, SEe = 0.27 cm2). Doppler-echocardiographic use of the Gorlin formula yielded the best prediction of the severity of mitral valve stenosis (concordance with invasive measurement in 82%). CONCLUSION: Pressure half-time is only a poor predictor of the severity of mitral valve stenosis. More accurate results are obtained by Doppler-echocardiographic applications of the continuity equation and especially the Gorlin formula.