The basic principle of the method described here is derived from a variant of the oscillation method. A reference impedance is connected to the mouth; between these two an oscillating flow is imposed. As a reference impedance we use a flexible tube, which acts as a virtually pure inductance or inertance. Respiration is hardly impeded. The only measured parameter is the alternating pressure in front of the mouth and this is easily picked up by a simple microphone. In contrast to former direct-display methods, the inertia and elasticity of the respiratory gas and the respiratory tract, i.e., airways including lungs and thorax, are also taken into account for the evaluation. The respiratory resistance is studied as a complex parameters, i.e., as an impedance. With the aid of diagrams or via electronic computation circuitry, the direct and continuous display of all impedance components such as its magnitude and phase, resistance, and reactance is possible. They can be read out as a function of time, respiratory flow, or volume.

No abstract

Based on the principles of classic film tomography, a new digital X-ray device for dental sites was developed and clinically evaluated. The tomosynthesis process produces several slices from a finite number of radiographs taken from different projection angles, obtaining a three-dimensional image of the jaws and teeth. During evaluation of an industrial prototype, a total of 52 tomosynthesis data sets were made covering different anatomic areas. Of those, 32 sets were assessed by ten radiologically experienced dentists. Anatomic regions not shown on conventional intraoral dental films were displayed due to the extraoral sensor. Diagnostic images of high value were mainly achieved within the scope of lateral views and transverse views in the frontal region. Even small structures such as the periodontal ligament could be shown in several planes, resulting in superposition-free representation. The elimination of metal artefacts caused by dental restorations was facilitated. However, improvements can be made in definition and resolution. Views in the sagittal plane and incomplete blurring of the contralateral jaw are difficulties that remain. The tomosynthesis process combined with a planned 3D representation is likely to be well suited for dental radiology. The use of such a device could be much less expensive than computed tomography (CT). Furthermore, it offers higher spatial resolution, exposes patients to less radiation, and could be easily used in daily practice, even chairside.

Various alternatives for program-controlled insulin delivery systems, on which we have been working since 1972, are described. Fixed-programmable and demand-programmable devices, both in two parts comprising separate control and delivery units, have been miniaturized and technically improved to the extent that they can now be used for the ambulant, long-term treatment of diabetic patients. The electronic drive systems, including control and safety circuits, that are discussed using the demand-type system as an example have been conventionally designed, using CMOS technology. The mechanical components of the insulin-delivery devices, in particular the roller pump driven by a stepping motor, have been developed in such a way that they can also be employed in implantable devices, without any essential modifications. Particular attention was thus paid to the features of miniaturization, high insulin concentration, low energy consumption, and a high degree of safety and reliability. The experience obtained from broad-based clinical trials of the devices is summarized briefly.

SUMMARYThis is a report of the implantation and first 100-day operation using a remote-controlled programmable insulin infusion device in an insulin-dependent diabetic. To prevent insulin aggregation, a special surface-active polymer developed by Hoechst AG, Frankfurt, was used as an additive.Implantation