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Biomedical subjects

F Knudsen

Publications and source records attributed to F Knudsen.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Use of ketanserin in anesthesia. A selective S2 serotonin receptor antagonist].

Serotonin is a vasoactive amine. It is formed in the chromaffin cells in the small intestine and is inactivated in the liver and lungs. The remainder is taken up in the thrombocytes so that only minimal quantities are found free in the plasma. The peripheral effect of serotonin occurs probably exclusively by means of a release of amine from the thrombocytes following local aggregation of these. Serotonin is thought to play a pathogenetic role in both systemic and pulmonary hypertension. Ketanserin is a serotonin antagonist with alpha-blocking effect. It reduces the blood pressure by reducing the peripheral vascular resistance without causing reflex tachycardia or fall in the minute volume of the heart. In the field of anaesthesiology, it may be employed in per- and postoperative hypertension but on account of the peripheral vasodilating effect it may also be employed in other conditions with peripheral vasoconstriction. Ketanserin has a moderate effect in cases of acutely developed pulmonary hypertension.

Anesthesia, Intravenous↗
PubMed1990

[The use of urapidil in anaesthesia. A selective S1A-serotonin receptor antagonist with antihypertensive action].

Serotonin is a vasoactive amine which is considered to play a pathogenetic role in systemic hypertension on account of the peripharal vasotonic effect of serotonin. The central serotoninergic neurones excitatory influence of the sympathetic tone may, however, be a contributory cause. Urapidil is a selective S1-serotonic receptor-agonist with alpha-blocking effect. This is considered to influence the presynaptic receptors of the serotoninergic neurones and thus to inhibit the excitatory influence on the sympathetic system. It reduces the blood pressure by reducing the peripheral vascular resistance without simultaneous provocation of reflex tachycardia or reduction in the minute volume of the heart. In anaesthesiology, this may be employed for perioperative hypertension. The preparation appears to be particularly useful in neuroanaesthesia as in contrast to other antihypertensive agents, it does not appear to alter the intracranial pressure.

Anesthetics↗
PubMed1990

Extracorporeal shock wave lithotripsy of kidney stones does not induce transient bacteremia. A prospective study. The Copenhagen Extracorporeal Shock Wave Lithotripsy Study Group.

During 58 extracorporeal shock wave lithotripsies 161 blood cultures were drawn to evaluate the incidence of bacteremia during the procedure. Only 3 blood cultures drawn during the procedure yielded bacteria, in all cases probably skin flora contaminants. Post-lithotripsy fever was noted in 29% of the patients, and could not be associated with transient bacteremia and was not influenced by antimicrobial prophylaxis. Patients with a positive urine culture after extracoporeal shock wave lithotripsy may have an increased risk of septicemia.

Adult↗
PubMed1989

Protein C assays in uremia.

Protein C was determined in 42 patients with terminal uremia and 20 healthy controls in three different ways 1) anticoagulant activity 2) amidolytic activity 3) antigen level. Protein C anticoagulant activity was markedly decreased in uremia, but was partly normalized during hemodialysis treatment, whereas the amidolytic activity and antigen level of protein C were normal and without changes during dialysis. The activities and antigen levels of factor II and X were normal before and after hemodialysis. In anticoagulated patients we found a good correlation between prothrombin levels and protein C levels determined with three different assays. We did not find any evidence for a defect carboxylation of protein C as the cause for the defective protein C in uremia. The BaCl2 precipitation in the Protein C anticoagulant assay was incomplete both in uremia and in controls but without differences between the two groups. In vitro addition of urea and creatinine did not decrease protein C activity. The cause of the defective protein C in uremia is still not known but it might contribute to thromboembolic complications.

Adult↗
PubMed1989

Protein C in renal allotransplantation during the perioperative period.

Protein C activity, both coagulant and amidolytic, as well as antigen level were studied during the perioperative period in 40 renal transplants recipients and 21 healthy controls. At transplantations the protein C coagulant activity was significantly lower in the patients than in the normal controls, and further decreased in the patients during the first week after transplantation, whereas the amidolytic activity of protein C was normal and the protein C antigen level was elevated. In the patients with established kidney function, protein C coagulant activity was higher than in patients with impaired graft function. Furthermore, it seems that the protein C coagulant activity was closely related to changes in graft function in the 11 patients with graft rejection episodes. The low protein C coagulant activity following renal transplantation could be a contributing factor to thromboembolic complications.

Adolescent↗
PubMed1989

Further investigations of the defective protein C in hemodialysis, hemofiltration and continuous ambulatory peritoneal dialysis.

Protein C activity was determined in patients with terminal renal failure treated in three different ways: hemodialysis (n = 20), hemofiltration (n = 7) and continuous ambulatory peritoneal dialysis (n = 7). The protein C activity was decreased in terminal uremia, independent of the kidney replacement therapy employed, compared with 21 normal controls. In the hemodialysis patients protein C activity increased significantly during a hemodialysis treatment, whereas hemofiltration treatment normalized the depressed protein C activity. In vitro experiments with dialysis and with inhibition of normal plasma with ultrafiltrates could not reveal the presence of an inhibitor of protein C in uremic plasma.

Adolescent↗
PubMed1989

Release of granulocyte elastase and complement changes during hysterectomy.

Complement activation and release of granulocyte elastase has been previously reported during major vascular surgery and has been ascribed to plasma/cell interactions with foreign surfaces or to administration of blood or plasma. The effect of uncomplicated general anaesthesia and surgery, not requiring blood or plasma, on complement activation and signs of proteinase release was assessed by measuring C3d and elastase-alpha-1 PI, respectively, in nine patients undergoing elective hysterectomy. There was a minor decrease in plasma C3d during anaesthesia, surgery and in the post-operative period caused by the diluting effect of intravenous fluids. Elastase alpha-1 PI remained largely unchanged until the first post-operative day, when a significant increase was seen (p less than 0.05); on the second and third day significant elevated values were still observed. Release of granulocyte elastase seems to be a generalized response to surgical trauma and may be a part of the endocrine-metabolic stress response.

Adult↗
PubMed1988

Complement and leukocyte changes during major vascular surgery.

To gain further insight into the effects of major vascular surgery involving the abdominal aorta on complement and leukocytes, serial measurements of leukocyte and differential counts, plasma concentrations of C3d, and granulocyte elastase bound to alpha1 proteinase inhibitor (E-alpha1PI) were made after aorta declamping in a group of patients not receiving blood or plasma. In the hours after declamping, lymphocyte count decreased, whereas an increase was noticed in leukocytes, neutrophils, and plasma E-alpha1PI. Complement activation was not found. Previous reports on complement activation during aortic surgery probably reflect the administration of blood and plasma during the surgical procedures. Whether aortic cross-clamping or interaction between granulocytes and the aortic prothesis is responsible for the release of lysosomal enzymes during the procedure warrants further studies.

Aorta, Abdominal↗
PubMed1988

Complement and leukocytes during cardiopulmonary bypass: effects on plasma C3d and C5a, leukocyte count, release of granulocyte elastase and granulocyte chemotaxis.

In an effort to further elucidate the complex changes in the complement-leukocyte system during cardiopulmonary bypass (CPB), plasma levels of C3d, C5a, and granulocyte elastase bound to alpha1-proteinase inhibitor (E-alpha1 PI) were followed prior to, during, and after CPB. Leukocyte and differential cell counts and granulocyte migration were also determined. Complement activation was documented during CPB by an increase in plasma C3d corrected for hemodilution. Significant amounts of C5a were not revealed. Cell counts decreased during CPB but, if corrected for hemodilution, remained unchanged apart from a slight decrease in lymphocyte count after 60 minutes. Eighteen hours after CPB, neutrocytosis and lymphopenia occurred. Plasma E-alpha1 PI increased during CPB, reflecting release of granulocyte lysosomal enzymes. Granulocyte migration was transitorily depressed during CPB, and it was shown that this was due to the appearance of an intrinsic cellular defect. CPB is associated with acute changes in cells and plasma, resembling an acute whole-body inflammatory response, with transitory impairment of granulocyte migration. The clinical significance of these observations remains to be determined.

Aged↗
PubMed1988

Haemostatic aspects of renal transplantation.

Platelet function and protein C activity and antigen level was studied in 31 renal transplant recipients and 10 healthy controls. The patients were divided into three groups: (I) cyclosporin treated, (II) azathioprine treated, and (III) azathioprine treated patients with chronic rejection. The platelet function in the renal transplant patients was normal and there was no difference between groups I and II. The specific activity of protein C was decreased in patients after renal transplantation and decreasing protein C activity and progressive renal failure was found to be positively correlated in the azathioprine treated groups.

Adult↗
PubMed1988

Protein C in acute renal failure.

In 16 patients with acute renal failure we studied protein C activity, both coagulant and amidolytic, as well as protein C antigen level. Protein C coagulant activity was markedly decreased in acute renal failure. Furthermore, changes in kidney function were paralleled by alterations in protein C coagulant activity. The amidolytic activity and antigen level of protein C were normal in most cases, and the changes observed in a few patients seem clearly related to changes in liver function. This defective protein C could contribute to the thrombotic tendency reported in patients with acute renal failure.

Acute Kidney Injury↗
PubMed1988

Continuous arteriovenous hemofiltration--a new treatment in hypercalcemic crisis.

A case of hypercalcemic crisis, with accompanying anuria, due to recurrence of a parathyroid carcinoma and unresponsive to conventional medical treatment, was treated with continuous arteriovenous hemofiltration (CAVH). A maximum of 24 mmol of calcium was removed per 24 h by CAVH and serum calcium was temporarily normalized. Rising values during continued treatment necessitated acute parathyroidectomy. CAVH may represent a new treatment in hypercalcemic crisis, unresponsive to medical treatment.

Adult↗