[Catheter tip force probe: a paraclinical development for per- and postoperative monitoring in heart surgery]. / Katheterspitzenkraftaufnehmer: Eine kliniknahe Entwicklung zur per- und postoperativen Uberwachung in der Herzchirurgie.

Local intramyocardial "one-point" force measurement is well adapted to the myocardial architecture. The dense three-dimensional muscle network does not permit direct measurement of longitudinal tension in a particular bundle of muscle fibers. However, measurements on the skeletal muscle have shown changes in tendon stress to be strictly proportional to changes in local force measured simultaneously at different sites on the gastrocnemial muscle. In the heart in situ the response to inotropic and pre- and afterloads changes is extremely sensitive. However, in comparison to left ventricular pressure, local force measurements at different sites and in different ventricular layers show distinct force gradients and phase dislocation, indicating a wide range of inhomogeneities in ventricular dynamics. The method is suitable for clinical application in cardiac surgery: the probe may be implanted directly on the exposed heart or during ventricular catheterization using a pointed catheter tip force probe.

[Electron probe x-ray microanalysis of human aorta with isthmus stenosis]. / Menschliche Aorten mit Isthmusstenose: Elementbestimmungen mit der Elektronenstrahlmikroanalyse.

Aortas with isthmus stenosis (coarctation) can be regarded as a model for those changes of the vessel wall, that depend on blood pressure, as one can compare the proximal region (high pressure) with the distal one (low pressure). The Na, Mg, P, S, Cl, K, and Ca content of the vessel walls of 5 patients (age: 2 months to 34 years) were determined by electron probe microanalysis. We have used cryostat sections and measured the element concentrations from the lumen to the outer media. In this paper we discuss especially the measurements of Ca and P, as the mineral being deposited in the vessel wall, e.g. in arteriosclerosis, contains Ca and P. Up to 18 years Ca and P enrichments are found only in a subintimal band parallel to the lumen. The proximal region of the aorta of a 34 years old patient, however, demonstrated Ca and P enrichments in the whole media with a high peak in the subintimal band. The enrichments are proximally always higher than distally. Only in the distal region of the 2 months old infant no Ca or P enrichments were found, but they appeared proximally. Thus high blood pressure causes an enrichment of Ca and P in a subintimal band very rapidly and promotes the mineralization of the vessel wall. The quantitative electron probe microanalysis demonstrated these pathological alterations.

Coarctation of the aorta. A risk factor in children for the development of arteriosclerosis.

Pressure recordings in 120 patients, aged 0-35 years, undergoing operation for coarctation of the aorta, show a slow but steady rise in both systolic and diastolic peak pressures, the highest peak registered being in patients aged 16-18 years. The finding of significant morphological changes in the aorta in this age group is the rule and these arteriosclerotic changes become more severe as the patients get older. In long-standing coarctation, the degree of mineralisation proximally is up to 10 times higher than distally. The microscopic and ultrastructural changes in the proximal segment are essentially arteriosclerotic. In conclusion, the role of coarctation of the aorta in the pathogenesis of arteriosclerosis is essentially that of hypertension, a most important risk factor of arteriosclerosis. Since arteriosclerosis also develops in the region of low blood pressure, other factors are operative. We suppose that the reduced pulse and volume pressures, which in turn diminish the "windkessel" function of the aorta may effect a change in the blood flow patterns to favour the development of arteriosclerosis.

[Wound healing after surgery by laser, scalpel and thermocautery (author's transl)]. / Vergleichende Beobachtungen zur Wundheilung nach Laser, Skalpell- und Thermokauterschnitt.

Laser-, thermocautery- and scalpelsurgery when compared in respect to their wound healing procedure have qualified as prepared for clinical application. On minipigs wound healing of skin scissions has been followed up morphologically in light microscopy and by testing the stress resistance of 16 days old scars. The fastest wound healing occurs after scalpel incision resulting in an almost perfect reconstruction of subepethelial tissue architecture at the 20th postoperative day. The initial tendency of laser incisions to dilate, which is still more pronounced in thermocautery wounds, causes a flat funnel shaped deformation of the scars, again more distinct after thermocautery. This is reflected in a still remaining slight disarrangement of the subepithelial collagenous fibres at the 20 postoperative day. Stress resistance is maximal in thermacautery scars, i. e. almost 30% higher than in scalpel and laser scars.

Comparison of the methods of cathodoluminescence, electronprobe microanalysis, and calcium staining, applied to human aorta with isthmus stenosis.

Electron probe x-ray microanalysis is a useful method for studying pathologic and age-related calcification mechanisms in the aorta and in muscular arteries by means of elemental analysis in microareas. In the present investigation, this method was correlated with the histochemical alizarin-S-calcium staining and with cathodoluminescence analysis in the scanning electron microscope. Portions of the proximal region of a human aorta with isthmus stenosis was shock-frozen and sectioned in a cryostat. Serial sections were investigated by calcium staining, electron probe, and cathodoluminescence microanalysis. Using quantitative electron probe microanalysis of calcium and phosphorus, it was shown that the principal regions of calcium phosphate mineralization could be located using either alizarin-S staining or cathodoluminescence analysis. The advantage of the cathodoluminescence analysis is its higher lateral resolution compared with that of light microscopy, and the fact that no special staining is required. In addition, it was possible to obtain scanning images, thus providing additional information about the topology of the tissue surface, which is necessary to decide whether or not the section is suitable for microanalysis. Quantitative microanalysis is a valuable tool for basic research on calcified arteries. The results of the combined analysis in the proximal and distal regions as well as in the stenosis will be published in a later paper.

[The use of laser in thoracic-, cardiac- and vascular surgery (author's transl)]. / Die Anwendung des Lasers in der Thorax-, Herz- und Gefässchirurgie

We carried out thoracic and cardiovascular operations with a 50 watt CO2-Laser. The advantage of this procedure: A minimal trauma of tissue in consequence of no use of selfcutting surgical instruments, bloodless incision at smallest area of coagulation and no possibility of displacement of infections and tumor cells. We believe that this new laser in all surgical disciplines introduced soon.