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Biomedical subjects

S Ottesen

Publications and source records attributed to S Ottesen.

23 records · Page 2Linked to original sources
PubMed1978

Cardiac effects of thoracic epidural analgesia before and during acute coronary artery occlusion in open-chest dogs.

The effects of thoracic epidural analgesia (TEA) on myocardial performance and metabolism and on the severity of an acute myocardial ischaemia, were studied in eight anesthetized open-chest dogs. TEA reduced mean arterial blood pressure (AP) by 26%, heart rate (HR) by 20%, left ventricular dP/dt by 37%, and myocardial oxygen consumption by 27%. Although arterial concentrations of free fatty acids, glucose and lactate were unchanged, their myocardial uptake was reduced in proportion to the reduction in mechanical activity of the heart. Acute ischaemic injury was estimated from epicardial ECG recordings 10 min after occlusion of a branch of the left anterior descending coronary artery. In seven of eight dogs TEA caused a substantial reduction in the severity of the acute myocardial ischaemic injury. In the eight dogs investigated, the sum of ST segment elevations in epicardial ECG recordings was reduced from 34.0 +/- 3.4 to 23.3 +/- 2.8 mV (mean +/- SEM, P less than 0.01). After restoration of AP and HR to control values with phenylephrine and atrial pacing, the favourable effect of TEA on myocardial ischaemic injury was abolished. It is concluded that TEA effected a reduction in the severity of myocardial ischaemia in open-chest dogs, mainly through reduction of myocardial mechanical activity with consequent reduction of myocardial metabolism.

Anesthesia, Epidural↗
PubMed1978

The influence of thoracic epidural analgesia on the circulation at rest and during physical exercise in man.

The effects of thoracic epidural analgesia (TEA) on the circulation at rest, during, and after physical exercise were investigated in 10 volunteers. At rest, TEA did not affect oxygen consumption (VO2) or cardiac output (Q), but heart rate (HR) was, increased by 7 beats/min, and stroke volume decreased correspondingly by 13 ml. Systolic arterial blood pressure was slightly reduced, but no other changes in systemic or pulmonary circulatory parameters were produced. TEA did not change VO2 during exercise, a 2.11/min reduction of Q being accompanied by a 4.2% increase of oxygen utilization coefficient. HR showed a relative reduction of about 10%. At moderate work loads during TEA, systemic arterial blood pressures were significantly lower than during control exercise. The resulting rate pressure product (RPP) was markedly reduced, while total peripheral resistance (TPR) remained unchanged. During recovery after the termination of exercise during TEA, VO2, Q, HR, RPP and TPR fell more rapidly towards values obtained at rest. From a clinical point of view the results support the safeness of TEA and also support its use in surgical patients with heart disease.

Adult↗
PubMed1978

Cardiovascular effects of epidural analgesia. I. Thoracic epidural analgesia. An experimental study in sheep of the effects on central circulation, regional perfusion and myocardial performance during normoxia, hypoxia and isoproterenol administration.

Some circulatory effects of thoracic epidural analgesia (TEA) were investigated in splenectomized, open-chest sheep during normoxia, hypoxia and isoproterenol administration. During normoxia, TEA caused comparatively marked reductions in systemic arterial blood pressure, total peripheral resistance and cardiac output. A fall in heart rate was not compensated for by any rise in stroke volume. Myocardial contractility (LV dd/dt/IP) was not affected by TEA. The proportion of cardiac output diverted to the blocked area was markedly increased. Compensatory vasoconstriction was not observed within the unblocked area in six out of nine animals. Myocardial blood flow showed a pronounced reduction in accordance with the calculated changes of heart work, so that myocardial oxygen extraction remained unchanged. Studies under hypoxia revealed that cardiac responses to hypoxia in the sheep are mediated chiefly by neurogenic factors. TEA abolished the hypoxia-induced rise in heart rate but did not affect the increase in pulmonary vascular resistance caused by hypoxia. The administration of isoproterenol during TEA increased systemic arterial blood pressure, but due to further fall in total peripheral resistance it was not fully normalized. Cardiac output and heart rate increased markedly. Myocardial oxygen consumption and blood flow increased but did not reach control levels.

Anesthesia, Epidural↗
PubMedDate not supplied

In vitro studies of human bladder cancer.

Explantation and cultivation in vitro of 55 human biopsies of histologically normal urothelial tissue, and 63 biopsies from transitional cell carcinomas (TCC) revealed a primary success rate of about 75% and a secondary success rate of about 50% with no significant differences, between normal and TCC derived cultures. While only half of the subcultured biopsies of normal origin were able to grow for more than 4 passages all TCC derived cultures were able to do so. Based on morphology, life span, invasive growth into co-cultured fragments of embryonic chick heart, and tumorigenicity in nude mice the following transformation grades (TGr) were defined: Normal (TGr 0), non-malignant with prolonged, but finite life span (TGr I), premalignant with infinite life span but without tumorigenic and invasive potential (TGr II), malignant with infinite life span and tumorigenic and invasive properties (TGr III). Differentiation between TGr I - TGr III was possible by several other parameters, including cytological characteristics, molecular and immunological surface structure, relative oncogene expression, pyruvate kinase isoenzymes, DNA Repair, and growth pattern. However, in addition to these common characteristics, the individual cell lines of the various categories of transformation showed differences that allowed the identification of well defined cell lines and sublines.

Animals↗