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Biomedical subjects

K Andersen

Publications and source records attributed to K Andersen.

At least 73 records · Page 4Linked to original sources

Detection of glass foreign bodies by radiography.

During a 14-month period patients with suspected glass foreign bodies were radiographically examined before removal of the glass. In 25 out of 26 patients the glass foreign bodies were detected. In 9 patients the glass foreign bodies had been overlooked on previous visits to doctors or hospitals, where the examination had been limited to inspection and sometimes probing of the wound. Almost all glass foreign bodies can be detected radiographically. With high-resolution or mammographic techniques even minute splinters may show up.

Adult

Left main or proximal left anterior descending coronary artery disease: detection by echocardiographic evaluation of interventricular septal function during exercise.

Forty patients with coronary artery disease were studied prospectively to investigate whether stenosis of the left main (LMCA) or left anterior descending coronary artery, proximal to the first septal branch (proximal LAD), could be detected by M-mode echocardiography during exertion. The interventricular septum was visualized in 30 of the patients during bicycle exercise in the semisupine position, all with simultaneous occurrence of electrocardiographic evidence of myocardial ischaemia. Fifteen of these had LMCA or proximal LAD stenosis. Systolic motion and thickening of the septum decreased significantly from rest to peak exercise in patients with LMCA or proximal LAD disease while it increased in those without. The results suggest that M-mode echocardiography during exercise in patients with coronary artery disease might identify those with LMCA or proximal LAD stenosis.

Adult

Brain oedema and blood-brain barrier permeability in pulsatile and nonpulsatile cardiopulmonary bypass.

In pigs subjected to pulsatile or nonpulsatile cardiopulmonary bypass (CPB) at normothermia for 3 hours, evaluation was made of water content in brain tissue (specific gravity measurements), blood-brain permeability to serum proteins (immunocytochemical demonstration of extravasated proteins, using peroxidase-antiperoxidase technique) and histopathology (paraffin sections). The specific gravity in parietal cortex was higher after pulsatile than after nonpulsatile CPB or in control pigs, the change corresponding to a 6.3% water increase. The tissue water content was unchanged in the internal capsule, basal ganglia and nucleus accumbens after CPB. The vascular permeability to serum proteins was unchanged after nonpulsatile CPB, but after pulsatile CPB minute foci of extravasated serum proteins appeared. All the animals showed dark neurons in cortical and subcortical regions, but these could have been artefacts in immersion-fixed tissue. There were no other signs of ischaemic tissue damage. The study indicated that cortical oedema may follow pulsatile CPB, the cause being altered permeability of the blood-brain barrier to serum proteins.

Animals

Dislocation of the superior tibiofibular joint.

Derangements of the superior tibiofibular joint are divided into anterolateral, posteromedial and superior dislocations and chronic instability. Two cases of anterolateral dislocation, both needing open reduction, are presented together with a case of posteromedial dislocation.

Adolescent

Pulsatile flow during cardiopulmonary bypass. Evaluation of a new pulsatile pump.

Pulsatile cardiopulmonary bypass (CPB) has been suggested to be superior to nonpulsatile CPB. This report concerns a newly developed pulsatile pump for clinical use. It is designed as a positive displacement pump, with blood allowed to collect in a valved cavity from which it is ejected by the reciprocating action of a piston. Using a uniform procedure of anaesthesia and surgery, 14 pigs were subjected to CPB at 37 degrees C for 3 hours. The pulsatile pump was used in seven pigs and a conventional roller pump in the other seven. The wave-form of the pulse during pulsatile CPB was similar to that recorded in the pigs before bypass. The values for rate of pressure change with respect to time (dp/dt) obtained in the aorta were close to the pre-CPB values. No difference was found between the two groups with respect to platelet count or haemolysis. The investigated pulsatile device appeared to be reliable and easy to handle, and the pulsation it produced closely resembled the physiologic pulse-wave form.

Animals

Prevention of postoperative deep venous thrombosis. Low-dose heparin versus graded pressure stockings.

In a prospective, controlled clinical study prevention of postoperative deep venous thrombosis by low-dose heparin (Heparin Leo 5 000 I.U. subcutaneously twice daily) was compared with graded compression stockings (TED stockings, Kendall Co.). One hundred and twelve patients, admitted during a period of one year for elective major surgery, were allocated to one of the two treatment groups. In order to detect deep venous thrombosis the 99mTc-plasmin test was performed before the operative procedure and again 5 days later. Ninety-seven patients completed the study (45 patients in the heparin group and 52 patients in the stocking group). Venous thromboembolism was detected in 4 patients (8.9%) in the heparin group and in 3 patients (5.8%) in the stocking group (p greater than 0.05). In 6 patients the plasmin test was positive and one patient in the heparin group died following pulmonary embolism. It is concluded that graded compression stockings can be used as an alternative to low-dose heparin for prophylaxis against deep venous thrombosis in elective general surgery.

Adult

Nonpulsatile cardiopulmonary bypass disrupts the flow-metabolism couple in the brain.

The effect of cardiopulmonary bypass on the relationship between brain glucose consumption and regional blood flow is unknown. We measured this relationship in pigs subjected to 3 hours of pulsatile or nonpulsatile cardiopulmonary bypass at normothermia and compared the results to the relationship established in a control group of pigs. A total of 10 regions were sampled in both hemispheres of the porcine brain. In control pigs, cerebral blood flow averaged 46 ml/100 gm and the glucose consumption, 21 mumol/100 gm/min. The ratio between blood flow and glucose consumption was close to 2 ml/mumol in all regions. In pulsatile cardiopulmonary bypass both the whole-brain average and the regional values declined, so that the ratio remained the same, about 2 ml/mumol. In nonpulsatile cardiopulmonary bypass regional blood flow remained normal; the average was 49 ml/100 gm/min, whereas the average glucose consumption declined to 16 mumol/100 gm. In regions with high blood flow rates, the ratio between blood flow and glucose consumption increased to about 3 ml/mumol, indicating perfusion in excess of metabolic demand. We conclude that nonpulsatile cardiopulmonary bypass at normothermia affects the metabolic flow regulation in the brain by interfering with the myogenic contractility of cerebral arterioles.

Blood Flow Velocity

ATP-content in muscular interstitial fluid during pulsatile and non-pulsatile cardiopulmonary bypass in pigs.

The potential benefit of pulsatile flow during cardiopulmonary bypass (CPB) has been discussed extensively, but the debate is still unsettled. Release of intracellular ATP is a useful indicator of cellular damage; we have measured the ATP content in perfusates from muscles in pigs undergoing pulsatile or non-pulsatile CPB for 100 min at 37 degrees C. In 5 pigs the Polystan Pulsatile Pump was used and in 5 pigs a conventional roller pump. 11 pigs served as controls; 6 received heparin like the animals subjected to CPB, whereas the remaining 5 animals were not heparinized. ATP was measured by the firefly luminescence technique. At the start of the CPB or control period the ATP content was very low in all 4 groups. In the non-heparinized controls ATP continued to decrease, whereas in the other 3 groups ATP increased linearly during the 100 min of CPB or control period. It is concluded that, by this method, there was no significant difference between pulsatile and non-pulsatile CPB regarding damage to vascular endothelial or smooth muscle cells. However, heparinization per se caused a marked leakage of blood cells into the extravascular space even after the initial leakage from the cannulation had disappeared. This leakage was enhanced by non-pulsatile but not by pulsatile CPB.

Adenosine Triphosphate