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Biomedical subjects

K Andersen

Publications and source records attributed to K Andersen.

At least 109 records · Page 6Linked to original sources
PubMed1985

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↗
PubMed1985

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↗
PubMed1985

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↗
PubMed1985

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↗
PubMed1985

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↗
PubMed1984

Rotatory instability of cadaver knees after transection of collateral ligaments and capsule.

The importance of the medial and lateral compartment ligaments of the knee in relation to valgus-varus and axial rotation instability was investigated. Mobility patterns were drawn from 20 osteoligamentous knee preparations after successive transections of the structures. Cutting of the medial collateral ligament resulted only in slight valgus instability and modest anteromedial instability. When the medial posterior joint capsule was also cut, both types of instability increased, and moreover, the knee became posteromedially unstable. Cutting of the lateral collateral ligament produced only a little varus instability and anterolateral rotatory instability, but varus instability increased considerably when the posterior lateral capsule was also transected. In this latter situation, even marked posterolateral rotatory instability was found. Isolated transection of the medial or lateral collateral ligament did not cause any major valgus or varus instability, but when the posterior capsule was also transected, a considerable degree rotatory instability could be found even though the cruciate ligaments were intact.

Biomechanical Phenomena↗
PubMed1984

T lymphocyte subsets in homosexual men from Copenhagen.

Screening of sixty-six asymptomatic homosexual men from Copenhagen revealed significantly lower Leu-3a/Leu-2a ratios as compared to controls. Ten (15%) of the homosexuals had a ratio less than or equal to 1.0. The low Leu-3a/Leu-2a ratios were the result of an increase in the absolute number of Leu-2a cells. Homosexuals with many partners and those who had been sexual partners of patients with the acquired immuno-deficiency syndrome (AIDS) had significantly lower ratios than those without these features. Cytomegalovirus was isolated from urine and/or sputum of 15% and this was associated with a Leu-3a/Leu-2a ratio less than or equal to 1.0. The observed immunological abnormalities could either represent latent infection with the putative AIDS agent or alternatively be caused by repeated infections and/or exposure to allogenic spermatocytes or lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1984

The development of simple acoustic reaction time in normal children.

Normative data on the simple acoustic reaction time were obtained from 56 children without neurological or psychiatric symptoms aged between four and 14 years, and the results were compared with those for an adult reference group. Mean reaction times declined precipitously from 465 msec at age five to 190 msec at 15 years. The relationship between reaction time and age during childhood can be described by a linear equation in a log-log system. The adult level is achieved at 16 years.

Acoustic Stimulation↗
PubMed1984

Sympathetic vasoconstrictor nerve function in alcoholic neuropathy.

The peripheral sympathetic vasomotor nerve function was investigated in 18 male chronic alcoholics admitted for intellectual impairment or polyneuropathy. By means of the local 133Xenon washout technique, the sympathetic veno-arteriolar axon-reflex was studied. This normally is responsible for a 50% decrease in tissue blood flow, when the ankle is lowered 40 cm below heart level in the supine individual. The patients with moderate to severe polyneuropathy, taken as a group, did not differ significantly from the group of patients with no or only mild polyneuropathy, although a lesser response was seen (18% and 48% decrease respectively). However, in three patients with moderate neuropathy, and in one patient with no signs of neuropathy, this veno-arteriolar reflex was absent, indicating dysfunction of the peripheral sympathetic adrenergic nerve fibres. The three patients also showed a lesser degree of arteriolar constriction during 45 degrees passive head-up tilt, although none developed symptoms of orthostatic hypotension. Anhidrosis of the feet was found in only three patients. This study lends support to the view that individual differences in the susceptibility to the deleterious effect of alcohol comprise not only the peripheral sensory and motor nerve fibres, but also the thin pseudomotor and vasomotor nerves.

Adult↗
PubMed1984

Peripheral neuropathy, cerebral atrophy, and intellectual impairment in chronic alcoholics.

Peripheral neuropathy, cerebral atrophy, and intellectual impairment was investigated in 46 males with alcoholic nervous system damage. An overall correlation was found between peripheral neuropathy and cerebral atrophy and between several of the individual neurophysiological and neuroradiological variables examined. There was also a correlation between cerebral atrophy and intellectual impairment. The findings support the view that alcohol in itself is toxic to central and peripheral nervous tissues, although a dose-response dependence could not be established.

Alcoholism↗
PubMed1984

Construction and use of a gene bank of Alcaligenes eutrophus in the analysis of ribulose bisphosphate carboxylase genes.

A gene bank of the DNA from the hydrogen bacterium Alcaligenes eutrophus ATCC 17707 was constructed in the broad host range cosmid vector pVK102 and established in Escherichia coli. A triparental replica plating procedure was developed to allow rapid screening of large numbers of isolated E. coli gene bank clones for complementation of A. eutrophus mutants. This procedure was used to identify hybrid cosmids that complemented CO2 fixation-negative (Cfx-), H2 uptake-negative (Hup-), and auxotrophic A. eutrophus mutants. The average insert DNA size in these hybrid cosmids was 22 kilobases. Nine hybrid cosmids that complemented ribulose bisphosphate carboxylase-negative (RuBPCase-) mutants were characterized. They fell into two distinct groups with respect to their restriction patterns. Complementing subclones from the two groups contained no common restriction fragments, but hybridization experiments indicated a high degree of sequence homology. Restriction fragments corresponding to one of the subclones were absent in total DNA from a cured strain that had lost plasmid pAE7, indigenous to the wild type. It is concluded that functional CO2 fixation genes in the A. eutrophus ATCC 17707 chromosome are reiterated on plasmid pAE7.

Alcaligenes↗
PubMed1984

Increased left ventricular emptying at maximal exercise after reduction in afterload.

Twelve healthy men were studied by M mode echocardiography during exercise to investigate the effect of afterload reduction on left ventricular function at maximal exertion. They performed two maximal exercise bicycle tests 4 hr apart while in the semisupine position and were given 20 mg nifedipine sublingually 30 min before the second test. During the first test end-systolic dimension decreased (p less than .01) and fractional shortening increased from rest to peak exercise (p less than .01), while end-diastolic dimension did not change significantly. At maximal exercise systolic blood pressure was lower after nifedipine than in the preceding control test (202 +/- 10 [mean +/- SD] vs 212 +/- 14 mm Hg; p less than .01), while heart rate was not significantly changed (168 +/- 15 vs 162 +/- 13 beats/min). End-systolic dimension was lower (25.6 +/- 3.3 vs 28.8 +/- 4.2 mm; p less than .01) and fractional shortening higher (50.7 +/- 6.0% vs 45.3 +/- 7.0%; p less than .01) while end-diastolic dimension was unchanged (52.3 +/- 1.9 vs 52.4 +/- 2.6 mm). Our data indicate increased left ventricular emptying at maximal exercise after nifedipine, most probably due to reduction in afterload.

Adult↗
PubMed1984

Effects of spontaneous respiration on left ventricular function assessed by echocardiography.

The effects of quiet respiration on assessment of left ventricular function by two-dimensional echocardiography were investigated in 12 healthy men. End-diastolic area in the parasternal short-axis view decreased with inspiration (from 17.3 +/- 2.1 [mean +/- SD] to 16.0 +/- 2.1 cm2, p less than .01), while end-systolic area did not change (from 7.6 +/- 1.4 to 7.7 +/- 1.5 cm2; NS). A fixed cursor that was located through the center of the left ventricular area at end-expiration made a tangential cut of the area at end-inspiration were smaller along the cursor than through the center of the short-axis area both at end-diastole (1.9 +/- 1.7 mm; p less than .01) and end-systole (3.8 +/- 4.0 mm; p less than .01). Our results suggest a need for standardization with regard to respiratory phases in assessment of left ventricular function by two-dimensional echocardiography and indicate the occurrence of inspiratory reduction of left ventricular stroke volume associated with decreased diastolic filling. Motion of the heart relative to the echo beam may play a part in the respiratory variations in left ventricular dimensions assessed by M mode echocardiography.

Adult↗