Influence of solvents and gas chromatographic injector conditions on the detectability of nitroaromatic compounds.

We investigated the influence of four common solvents and of several liner packings of a split/splitless injector on the gas chromatographic behavior of trinitrotoluenes and related nitroaromatic compounds. The highest peaks are observed using toluene in combination with an empty liner or with a prepacked CarboFrit liner. In particular, the peaks of trinitrotoluene isomers and 1,3,5-trinitrobenzene significantly decreased or even totally disappeared when using quartz wool or glass wool, even when treated with dimethylchlorosilane. Similiar peak reductions are obtained with methanol or acetonitrile. Effects of decreasing peak are accompanied by the formation of two additional products when using methanol.

System for analyzing high-resolution three-dimensional coronary angiograms.

Three-dimensional (3-D) high-resolution coronary angiograms offer a means for visualizing the entire coronary arterial tree from any orientation and for detecting and quantitating coronary arterial stenoses. Previously, a skilled operator had to perform several hours of tedious manual analysis using an interactive graphical user-interface (GUI) system (Tree Trace) to analyze a 3-D angiogram. The authors have devised an improved GUI system, consisting of three tools for analyzing 3-D angiograms. The Artery Extractor first performs automatic image-analysis operations to extract the central axes of the arterial tree. Next, using the Artery Display tool and results from the Artery Extractor, the operator can visualize structures in the angiogram and compute various measurements. Finally, the aforementioned Tree Trace tool can be used to manually correct irregularities in the automatically generated results of the Artery Extractor. The system greatly reduces operator analysis time, gives exactly reproducible results, uses true 3-D image-processing operations, and provides a comprehensive interface for visualizing and quantifying features of the 3-D coronary arteries.

[A rare case of tuberculosis of the maxilla, zygomatic region, maxillary sinus and facial skin in a patient with diabetes mellitus]. / Rzadki przypadek gruzlicy szczeki, okolicy jarzmowej, zatoki szczekowej i skóry twarzy u chorej na cukrzyce.

In an 82-year-old female diabetic tuberculosis involved the maxilla, zygomatic region, maxillary sinus and facial skin. No other foci of tuberculosis were found in the organism. The diagnosis and treatment are described stressing the extreme rarity of this involvement by tuberculosis.

Detection of mild coronary stenoses using the Dynamic Spatial Reconstructor.

The accuracy of the Dynamic Spatial Reconstructor (DSR) in the detection of moderate coronary artery stenoses was examined in 20 closed-chest dogs. Twenty-eight hollow plastic cylinders were embolized into the left coronary arteries and produced 25% to 56% reductions in arterial lumina diameter. For each dog, one three-dimensional (3-D) image of the heart was reconstructed from each DSR scan recorded during injection of contrast into the aortic root. Analysis involved blinded visual analysis by four independent observers of multiview projection images computed from the single 3-D image. Postmortem coronary angiograms of the isolated heart were considered definitive for location of the stenoses. Overall sensitivity of detection by DSR was 89% and specificity 81%. Sensitivity of detecting stenoses greater than or equal to 50% was 98%. Receiver operating characteristics (ROC) analysis showed that detection of stenoses in the left coronary arteries is of equal sensitivity and specificity.

Computed tomographic imaging of the coronary arterial tree-use of local tomography.

It has been demonstrated previously (see E.L. Ritman and A.A. Bove, in State of the Art in Quantitative Coronary Arteriography, p.67-78, 1986) that coronary artery anatomy can be visualized using high-speed, volume-scanning X-ray CT (computed tomography). In the current study it is demonstrated that local image reconstruction (i.e. the reconstruction kernel is ~2(+) mm long), as distinct from more conventional global image reconstruction (i.e. 200(+) mm kernel length), has the advantage of reducing the need for operator interactive image processing. In addition, the local reconstruction algorithm eliminates the need for recording the X-ray projection data over the full transaxial extent of the thorax because it requires only the X-ray attenuation data over the region of the heart. This latter aspect reduces the dynamic range requirements for the sensors and could reduce total X-ray exposure.

Assessment of the electrophysiologic, antiarrhythmic and haemodynamic profile of a new isoquinolinedione derivative.

The electrophysiological, antiarrhythmic and haemodynamic profile of a new isoquinolinedione derivative, 2,2'-[iminobis(trimethylene)]-di(4,4-dimethyl-1,3-(2H,4H)-isoqu inolinedione) hydrochloride (AR-03 Cl) was evaluated using dog models relevant to conditions in humans. In 16 animals dose-related effects on intercardiac conduction, ventricular refractoriness and on haemodynamic parameters were determined. In another 7 dogs antiarrhythmic actions of AR-03 Cl on delayed reperfusion arrhythmias following release of coronary artery occlusion after 2 h of obstruction were investigated. The results show: AR-03 Cl causes a significant prolongation in conduction through all parts of the conducting system. The AH-interval, HV-interval and QRS-duration are significantly lengthened. Ventricular repolarization is only slightly changed. There are no significant changes in heart rate, systolic and diastolic aortic pressure up to doses of 2 mg/kg b.w. However, left ventricular (dp/dtmax) and cardiac output are significantly reduced, and left ventricular enddiastolic pressure is increased. In acute myocardial necrosis delayed reperfusion arrhythmias are almost completely abolished, the effective dose is lower than that required with any other antiarrhythmic drug investigated so far in this particular experimental set-up. Further experimental and clinical testing of the new compound seems to be promising because of its strong dose-related antiarrhythmic potency. However, there is a need for further analysis of potential haemodynamic side effects of the new compound to establish the clinical significance of negative inotropic actions at therapeutic doses.

Some technical considerations in tomographic coronary arteriography.

Coronary artery anatomy can be visualized using high-speed, volume scanning x-ray CT. A single scan during a bolus injection of contrast medium provides image data for display of all angles of view of the opacified coronary arterial tree. Due to the tomographic nature of volume image data, the superposition of the vessels on themselves and on other contrast filled coronary arteries, such as would occur in an aortic root injection of contrast agent, can be eliminated. To achieve the goal of coronary arteriography using a single angiographic injection, the tomographic scanner must scan the entire volume encompassing the coronary arteries synchronously and within a brief period of time. The volume must be scanned so that the thickness of the scanned slices is less than the diameter of the smallest vessel desired to be visualized quantitatively. Preliminary results from a fast volume scanning CT scanner (the Dynamic Spatial Reconstructor) used to scan experimental animals are used to indicate the quantitative and qualitative impact of such variables as scanned slice thickness, scanned slice separation and angle between the vessel and the plane of the scanned slices.