[An animal experimental model for evaluating endothelial damage caused by various angiographic contrast media (author's transl)]. / Die Auswertung endothelschädigender Wirkungen verschiedener angiographischer Kontrastmittel an einem Tiermodell.

The endothelial damage caused by X-ray contrast media is tested on "en face preparations" of the rat aorta after silver staining. Hypertonic contrast media cause dehydration of the vessels so that solutions of silver nitrate penetrate into the media during the phase of rehydration whereby medial transverse lines are stained. These artifacts can be avoided by 3 minutes rehydration of the vessels by Ringer solution prior to silver staining. In addition it is recommended to add highly diluted silver nitrate to the fixing media in order to intensify the pattern of the endothelial silver lines. Modern contrast media may cause very little endothelial damage, however, significant differences can be detected when in addition to the evaluation of larger foci damages of single endothelial cells ("brown cells" with sparing of the nuclei and "pseudonuclei") are evaluated as well. No significant differences were found between the endothelial toxicity of meglumin diatrizoate and meglumin iothalamate.

[Investigations concerning the mechanism of contrast damage. The significance lipophilia (author's transl)]. / Untersuchungen über den Mechanismus von Kontrastmittelschäden, die Bedeutung der Lipophilie.

The damaging action on vascular endothelia of meglumin iothalamate and of meglumin ioxitalamate was tested on the rat aorta. Ioxitalamate was significantly better tolerated than iothalamate. The octanol-water-partition coefficient of various contrast media was evaluated by assessing the iodine content of the octanol phase after mixing. The coefficients found were about 100 fold lower than the coefficients computed by Levitan and Rapoport. The significance of the octanol-water-partition coefficient for endothelial injuries caused by contrast media is disputed.

Conservation of veins with preservation of viable endothelium.

The influence of cryoprotective agents on the endothelium of jugular veins of dogs was examined after silver staining on en face preparations. Comparatively low concentrations of Glycerol or DMSO caused distinct morphological changes. Quick-freezing of air-filled vessels by liquid nitrogen permitted reservation of vessels with vital endothelium and comparatively mild morphological changes. Such vessels could be replanted after quick thawing. 2-4 days thereafter the endothelium of the grafts contained nuclei stainable with hematoxilin. The area covered by this endothelium remained devoid of parietal thrombi 2-4 days after replantation. However, lyophilized vessels grafted under the same conditions, were covered by large mural thrombi 2-4 days after the grafting procedure and no endothelial cells were found histologically.

[Varicose veins: pathogenesis and therapy (author's transl)]. / Zur Pathogenese und Therapie des Krampfaderleidens.

Valvular lesions of the main venous stems are regarded as the predominant cause of the formation of primary varicose veins. Peripheral arteriovenous shunts are regarded as sequelae of varicose veins rather than their cause. The perforating and communicating veins are not involved in the pathogenesis of varicose veins. This opinion is supported by the demonstration of insufficiency of the main superficial venous stems in a series of 200 consecutive cases of primary varicosis, even if only the more peripheral veins were dilated. In addition, histological examination of the uppermost valves in the saphenous veins of patients and experimental studies on post-thrombotic vein valves corroborated these views. The therapeutic importance of high ligature of the saphenous veins is stressed. Removal of the dilated veins by stripping is best, but unnecessarily radical procedures should be avoided. A combination of stripping with sclerotherapy is recommended. The dangers of both forms of treatment are outlined.

Grid adhesion: a new type of tissue union.

Cyanoacrylate adhesives, applied as a continuous layer, bar the way for the ingrowth of vessels. A genuine tissue union is achieved when the adhesive is applied in the form of a grid. This is accomplished by painting the adhesive on the tissue by means of a roller made of Teflon or by means of a porous gauze, soaked in adhesive. The method was applied experimentally for skin transplantation, for the creation of portasystemic anastomoses, for reinforcement of fasciae and for closures of laparotomies without sutures as well as for hemostasis of lacerations of the spleen. Clinical experiences are reported.

[New experimental documents on circulatory reversal by arteriovenous fistula in ischemia of the extremities]. / Nouveaux documents expérimentaux sur l'inversion circulatoire par fistule artério-veineuse dans l'ischémie du membre.

The beneficial effects of circulatory reversal by lateral a.-v. fistula was confirmed in 20 hind limbs of dogs made ischaemic by Collagen embolisation. Although not done in the experiments presented here, rupture of the distal venous valves is advisable. The peripheral circulation was studied by measurement of venous pressures and by angiography. Retrograde infusions, with proximal tourniquet, confirmed reversal of flow veins to arteries. Return routes to the heart remain unknown.