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Biomedical subjects

J Rysavy

Publications and source records attributed to J Rysavy.

31 records · Page 2Linked to original sources
PubMed1982

Ivalon shavings: technical considerations of a new embolic agent.

Ivalon (polyvinyl alcohol sponge) shavings can be used as a permanent embolic material. When injected as a suspension with assorted particles of proper size, congenital arteriovenous malformations can be cured, eliminating the need for surgical excision.

Adolescent↗
PubMed1982

The site of arterial wall rupture in transluminal angioplasty: an experimental study.

The site of arterial rupture following arterial balloon dilatation was studied in postmortem canine arteries. An atherosclerotic plaque was simulated by insertion of a solid nylon ball. Longitudinal tears of intima and media were produced at the level of the nylon ball. The site of arterial rupture can therefore be predicted if localized changes of wall strength can be neglected. On the other hand, the site of arterial rupture in clinical cases will depend mainly on the consistency and tensile strength of the diseased artery.

Angioplasty, Balloon↗
PubMed1980

A method to analyze the motion of the endocardium during contraction.

Regional segmental wall motion analysis assumes a linear or radial grid system. In this study, motion patterns of points on the canine endocardium were evaluated. Radiopaque endocardial and epicardial markers were inserted along the anterior and posterior descending coronary arteries. Postoperative cine radiography showed that the endocardial markers did not move along either linear or radial grids. The endocardial and epicardial markers were shown to have different patterns of movement.

Animals↗
PubMed1978

Selective transcatheter embolization of the upper gastrointestinal tract: an experimental study.

Transcatheter gastric embolization using Ivalon shavings was performed on three groups of dogs. The left gastric artery and splenic branches (the short gastric and left gastroepiploic arteries) were embolized in Group I, the left gastric artery in Group II, and the splenic branches in Group III. Infarctions of the gastric mucosa occurred only in Group I. Ischemic ulcers developed in three of the five dogs in Group I and in one of the three dogs in Group II. The study suggest that embolization can only be performed safety if particles of 0.3 mm or larger are used.

Animals↗
PubMedDate not supplied

Experimental myocardial infarction in the closed-chest dog: a new technique.

The reliable and safe production of myocardial infarction in closed-chest animals is of paramount research interest. To date, the injection of particulate matter and the introduction of occlusive solid plugs have been described. Because of the limited size of the catheter, only small branches could be occluded, which resulted in a high incidence of mortality. A new simple technique is described that allows occlusion of a major coronary artery at a preselected site. An Ivalon (polyvinyl alcohol) plug compressed around the tip of an introducing wire is advanced through a selectively placed catheter into the coronary artery. It is felt in place for 5 minutes and assumes its original size upon contact with blood. Once the plug is re-expanded, the wire is withdrawn. The new technique was carried out successfully on nine dogs with no immediate fatality and myocardial infarction as demonstrated by cine ventriculography and histopathologic examination.

Animals↗
PubMedDate not supplied

Single barbed stainless steel coils for venous occlusion: a simple but useful modification.

Embolization of coils into the lungs has been reported following their use for the obliteration of large arteriovenous fistulas. So far, except for a recent report, they have not been used on the venous side of the circulation. Experimental studies at our institution demonstrated that the placement of coils on the venous side can result in embolization to the lungs, even when oversized coils are introduced. A simple, easy to perform modification of the standard stainless steel coils (Gianturco-Wallace-Chuang spring embolus and coilons) makes these devices safe embolic agents for used on the venous side of the circulation, as for example in the obliteration of spermatic veins.

Animals↗
PubMedDate not supplied

Double blind evaluation of the effects of various contrast media on extremity veins in the dog.

Canine superficial extremity veins were examined grossly and microscopically in a double blind fashion for endothelial damage and phlebitis one hour and four days after the injection of ionic monomeric or dimeric, and non-ionic monomeric, 300 mg I/ml, contrast media. Superficial veins of all four extremities and the tail vein were injected with the same amounts of contrast medium after application of tourniquets for 20 minutes following the injections. Silver staining and prefixation of the veins were done in situ. The specimens were evaluated together with cross-sectioned, hematoxylin-eosin stained biopsies. On the basis of a randomized study of 77 dogs, endothelial damage or thrombosis caused by various contrast media as seen in man was not demonstrated. This may be due to species differences. It is postulated that canine endothelium may have a higher resistance to contrast medium injury than human endothelium.

Animals↗