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Biomedical subjects

U E Kongsgaard

Publications and source records attributed to U E Kongsgaard.

13 recordsLinked to original sources
PubMed1992

Effects of heparin on proteolytic activities in human plasma.

The influence of unfractionated heparin [average molecular weight (MW) 10,000-15,000 kD] and low-molecular-weight heparin (average MW 400-600 kD) on the plasma kallikrein-kinin and the fibrinolytic system was studied in vitro. Unfractionated heparin added to plasma gave an increase in kallikrein-like activity with a corresponding decrease of prekallikrein and functional kallikrein inhibition values. Plasmin-like activity was also increased, but minor changes in plasminogen and no change in antiplasmin values occurred. The changes were less pronounced with low molecular heparin compared with unfractionated heparin. The proteolytic changes were reversed by protamine sulfate but not influenced by the protease inhibitor aprotinin. Gel filtration yielded proteolytic activities able to split the plasma kallikrein substrate S-2305 and, to a minor degree, the plasmin substrate S-2251. The proteolytic activities were not due to complex formation with alpha 2-macroglobulin. We speculate that heparin binds to prekallikrein to form a heparin-prekallikrein complex which undergoes conformational changes and displays a kallikrein-like activity with the ability to split small synthetic substrates. Whether it is capable to split natural substrates remains unresolved.

Aprotinin↗
PubMed1991

Autotransfusion after open heart surgery: characteristics of shed mediastinal blood and its influence on the plasma proteases in circulating blood.

Fourteen patients undergoing open-heart surgery received intermittent or continuous postoperative autotransfusion of shed mediastinal blood (minimum 400 ml during 6 h after surgery) collected in the cardiotomy reservoir. Hematologic variables and changes in the coagulation, fibrinolytic and plasma kallikrein-kinin systems were investigated in the reservoir blood at the beginning and after 6 h of autotransfusion, and in patient blood during and after surgery and before and after autotransfusion. Autotransfusion volume ranged from 400 to 1200 ml per patient (median 482 ml). The reservoir blood had a median haemoglobin level of 93 and 74 g/l, a platelet count of 71 and 119 x 10(9)/l, and plasma haemoglobin level of 3110 and 4100 mg/l before and after 6 h of autotransfusion, respectively. Further examination of the reservoir blood showed that it had undergone extensive coagulation and fibrinolysis as well as a moderate activation of the kallikrein-kinin system. Despite these extensive alterations in the reservoir blood, no major change could be found in the circulating blood after autotransfusion, except for a moderate increase in plasma haemoglobin from 180 mg/l to 430 mg/l. The clinical safety and simplicity of this technique were confirmed for autotransfusion of shed mediastinal blood up to 1200 ml.

Aged↗
PubMed1991

Haemodynamic effects of heparin during coronary bypass surgery.

Heparin has been suggested as an activator of the plasma kallikrein-kinin system, with possible formation of bradykinin, a potent vasodilator. Haemodynamic effects and changes in the kallikrein-kinin system were studied after heparin- and saline-injections in ten patients undergoing coronary bypass surgery. A moderate decrease in mean arterial pressure was found in all patients in the observation period, but significantly more at 2 and 3 min after heparin-injection compared with saline-injection. None of the other haemodynamic variables measured were significantly different when comparing heparin- to saline-injection. Heparin-injection resulted in significant changes in the kallikrein-kinin system, with a marked increase in spontaneous kallikrein-like activity as the most prominent feature, while no changes were found after saline-injection. Liberation of bradykinin would be expected to give a decrease in systemic vascular resistance with an increase in cardiac output. The results indicate that the plasma kallikrein-kinin system, though apparently activated after heparin-injection, does not contribute significantly to the decrease in arterial pressure in the patients studied.

Blood Pressure↗
PubMed1991

Duration of cardiopulmonary bypass compared with changes in the plasma protease systems.

Forty patients undergoing elective coronary artery bypass grafting were investigated concerning association between duration of cardiopulmonary bypass (CPB) and changes in the plasma protease systems. Spontaneous enzyme activity, proenzymes and functional inhibition capacities in the fibrinolytic, plasma kallikrein-kinin and coagulation systems were measured before, during and after CPB and in the immediate postoperative period. No clear relationship was revealed between changes in the measured variables and the duration of CPB.

Blood Coagulation↗
PubMed1990

[Severe, symptomatic hyponatremia].

Severe hyponatremia (serum sodium levels less than 120 mmol/l) is associated with increased morbidity and mortality. We report three cases where patients developed hyponatremia and severe neurological manifestations after medical treatment. The first two patients experienced episodes of general seizures and coma, but recovered in 24 hours without neurologic sequelae after correction of the electrolyte disturbance. The third patient developed the syndrome central pontine myelinolysis with pseudobulbar palsy and quadriparesis. Marked improvement occurred, however, and in three months the patient was almost completely recovered. The development of hyponatremia deserves special attention in connection with the use of diuretics, infusion of sodium-free carbohydrates and immediately after operation.

Adult↗
PubMed1990

[Correction of severe hyponatremia].

Profound hyponatremia is a life-threatening emergency which can result in permanent neurological damage. The rate at which severe hyponatremia should be corrected is the focus of clinical debate. It is important, however, to differentiate chronic from acute hyponatremia and to develop a plan for correcting hyponatremia. A treatment regime is suggested.

Acute Disease↗
PubMed1990

[Jet ventilation].

High frequency jet ventilation gives adequate alveolar ventilation with very small tidal volumes, gas exchange at lower airway pressure, reduced risk of pulmonary barotrauma, and less cardiovascular impairment. Use of small insufflation catheters facilitates surgery when access is restricted, as in laryngeal surgery, and makes it possible to ventilate a patient through a cricithyroid membrane puncture in an emergency situation. In intensive care medicine, jet ventilation can have some advantage over conventional ventilation in patients with bronchopleural fistulas, and when it is difficult to wean patients from a respirator. The article describes experience using an Acutronic AMS-1000 Universal Jet Ventilator.

Adult↗
PubMed1989

Changes in the coagulation and fibrinolytic systems during and after cardiopulmonary bypass surgery.

Components of the coagulation and fibrinolytic systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. The variables studied included prothrombin, antithrombin-III, spontaneous plasmin activity, plasminogen and functional antiplasmin activity. The variables were measured using chromogenic peptide substrate assays. A marked, transitory, increase in spontaneous plasmin activity prior to cardiopulmonary bypass, but after heparin injection was found. A decrease in antiplasmin activity during bypass was observed, while actual plasminogen level, when correcting for hemodilution, was unchanged. Both prothrombin and antithrombin-III paralleled the decrease in hemoglobin concentration during bypass. These findings suggest that the injection of heparin induced a transient activation of the fibrinolytic system, whereas no detectable consumption of the measured coagulation variables was observed.

Adult↗
PubMed1989

Different activation patterns in the plasma kallikrein-kinin and complement systems during coronary bypass surgery.

Components of the plasma kallikrein-kinin and complement systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. Spontaneous kallikrein activity (KK), plasma prekallikrein (PKK), functional kallikrein inhibition capacity (KKI), C3 activation products (C3-act), and the terminal complement complex (TCC) were measured. A marked, transitory increase in KK and a decrease in PKK were found prior to cardiopulmonary bypass just after heparin injection. An additional decline in PKK and KKI during bypass with a return to near control levels in the postoperative period was observed. C3-act increased in all patients during bypass, reaching a peak value at wound closure. The TCC concentration also increased significantly during cardiopulmonary bypass, returned to control levels in the early postoperative period, and then increased again in the late postoperative period. It is concluded that activation of the kallikrein-kinin system started after injection of heparin, prior to cardiopulmonary bypass. Activation of both the initial and the terminal complement cascade, however, started only after onset of cardiopulmonary bypass.

Adult↗
PubMed1989

Changes in the plasma protease systems during open-heart surgery with dextran vs. Ringer acetate as priming solution.

Two different priming solutions for cardiopulmonary bypass (CPB) were studied in regard to possible influence on the plasma protease systems. The study was performed on 20 patients undergoing elective coronary artery bypass grafting. In ten cases the priming solution contained 1,000 ml dextran (MW 70,000) and in ten it consisted only of Ringer's acetate solution. The same level of haemodilution was established during CPB in the two groups. Clinical variables and laboratory data were monitored. Spontaneous kallikrein activity, plasma prekallikrein, functional kallikrein inhibition capacity, spontaneous plasmin activity, plasminogen, functional antiplasmin activity, prothrombin and antithrombin-III were measured, using chromogenic peptide substrate assays before and during CPB as well as in the postoperative period. The antiplasmin activity decreased more in the dextran than in the Ringer group following cardiopulmonary bypass but the difference was without clinical significance. No statistically significant intergroup difference was found in the other measured variables of the kallikrein-kinin, fibrinolytic and coagulation systems.

Aged↗