Biomedical subjects

U Beyer

Publications and source records attributed to U Beyer.

At least 37 records · Page 2Linked to original sources

PubMed1992

Experimental selective myocardial infarction in the dog without open-chest-surgery.

In 16 dogs, a selective myocardial infarction (MI) was experimentally provoked without open-chest-surgery by means of microspheres (MS) injected into a Judkins-catheter positioned into the left anterior descending coronary (LAD) under fluoroscopy. This was shown by ECG-abnormalities, increase of the serum-enzymes of myocardial necrosis, decrease of left ventricular end diastolic pressure (LVEDP), wedge pressure, and cardiac output. After 5 weeks, thoracotomy showed a myocardial infarction limited to the anterior wall of the heart, which was of subendocardial location and consisted of multiple zones of microinfarction. Histological examination of the corresponding area showed necrosis of myocardial muscle fibres.

Animals↗

PubMed1992

A microcorrosion cast study for analyzing a new method of indirect myocardial revascularization.

In order to study the process of angiogenesis a free skeletal muscle flap was transplanted onto the myocardium of the dog. A microvascular anastomosis with the internal mammary artery (IMA) provided the blood flow to the free graft. In 6 dogs, a myocardial infarction of the anterior wall was induced in order to produce a tissue injury. Four weeks later the skeletal muscle flap was transplanted onto the area of infarction in two dogs with its pars anterior in contact with the heart. In two dogs, the muscle was grafted with its pars posterior, i.e. the muscle fascia between the heart and the graft. In two other dogs, the flap was transplanted with its pars anterior in contact with the heart onto a healthy myocardium. Two animals with infarction were left as controls. Eighteen weeks later a microcorrosion cast was prepared from the hearts with the muscle flap. This evidenced neoangiogenesis in the heart only after transplantation of the graft with its pars anterior onto the myocardium whether it was ischemic or not. The intact muscle fascia, though, inhibited sprouting of vessels. In the controls no angiogenic activity was noted. Results are discussed with regard to the probable origin of the neovessels.

Animals↗

PubMed1992

[Neo-angiogenesis after transplantation of a free skeletal muscle flap to the myocardium of the dog].

For the study of the process of neovascularization the effects of the transplantation of a free skeletal muscle flap on the heart of the dog were studied. For this purpose, in 14 mongrel dogs a myocardial infarction of the anterior wall of the heart was produced by the selective injection of microspheres into the left anterior descending artery. In 12 of those, on the area of infarction 4 weeks later a free pectoralis muscle flap was transplanted with its pars anterior in contact with the myocardium (group A). The arterial anastomosis was achieved with the internal mammary artery, the venous flow directed into the right atrium. In 2 other dogs (group B) the pectoralis flap was transplanted with irt pars anterior on a healthy myocardium. In 2 further dogs (group C) the pectoralis flap was transplanted on a infarcted myocardium with its pars posterior, i.e. the muscle fascia interponed. 16 weeks later a microcorrosion-cast-preparation and histological examinations showed in group A and B a prominent capillary network penetrating from the muscle into the myocardium, whereas in group C the muscle fascia inhibited this process. Thus, for the process of neovascularization the "bloody" contact between a skeletal muscle graft and the myocardium is necessary. Results are discussed with regard to possible factors inducing neoangiogenesis.

Anastomosis, Surgical↗

PubMed1992

Cardiac arrhythmias during experimental induction and management of myocardial infarction in the dog.

The experimental production of a myocardial infarction (MI) in the dog was achieved adopting a new catheter technique. After induction of the MI, a variety of arrhythmias appeared and were classified according to the Lown-classification as more or less severe. The therapy was achieved with antiarrhythmics class 1-111 (Vaughn-Williams classification) for late premature ventricular beats or couplets. Sinus tachycardia was often terminated by occular or sinus carotis pressure or a new selective sinus blocking agent. Results showed Amiodarone to be the drug of choice in the treatment of severe arrhythmias (Lown IV and V) like triplets or salves of extrasystolies. Ventricular fibrillation always resulted in the death of the animal, because fibrillation was not convertible by direct current cardioversion, endovenous injection of Lidocaine or even internal cardiac massage. The registration of hemodynamic parameters (left ventricular end diastolic pressure, wedge pressure, pulmonary and aortic pressure) was shown to be important in controlling the therapy, as well as blood gas and electrolyte analysis.

Animals↗

PubMed1992

A cardiac assist device as blood supply in ischemic heart disease.

Before the event of modern bypass surgery revascularisation of the heart was tried with the transplantation of pedicled muscle flaps onto the heart. For patients who cannot undergo bypass surgery this method could be--in a modified way--of help. This was shown in 12 dogs. In those a free muscle flap was transplanted onto the heart which had undergone a previous artificial infarction. The muscle flap was anastomosed with the a. mammaria, venous flow was directed into the right atrium. After 5 months the muscle was almost completely atrophic, but a fit capillary network was penetrating the underlying myocardium.

Animals↗

PubMed1988

[Perinatal problems in fetal macrosomy and its relation to maternal Hb A1C].

Although the frequency of macrosomic newborns decreased within the last years due to an intensive centralized care of women with diabetes mellitus, 175 new borns had a birth weight of more than 4,000 grams in 1986 (total number of deliveries 2,339). Within this collective increasing maternal as well as fetal risks and perinatal complications increased rapidly corresponding to the rising birth weight. When clinical parameters were related to maternal levels of HBA1C, which was determined immediately after delivery, a dependency of the height of glycolised hemoglobin was related to several perinatal problems e.g. maternal obesity, gestosis, maternal-fetal disproportion, operative delivery and fetal morbidity. These data stress upon the necessity of a general screening program for the early detection of metabolic dysfunction of carbohydrate.

Birth Weight↗

PubMed1977