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Biomedical subjects

F Laerum

Publications and source records attributed to F Laerum.

At least 55 records · Page 3Linked to original sources
PubMed1984

Heparin treatment of deep venous thrombosis in 280 patients: symptoms related to dosage.

280 patients with phlebographically proven deep venous thrombosis received intravenous heparin infusion, mean duration 6.8 days, mean dose 370 U/kg/day. In 58 patients (21%) there was no apparent predisposing factor. Leg pain diminished more rapidly than edema. At discharge, 46% had edema. Symptoms suggesting pulmonary embolism (PE) occurred in 13 patients (4.6%) whose mean daily heparin dose was similar to that of the others. The only fatal PE occurred three days after cessation of heparin administration. Eight patients (3%) experienced major bleeding, the only fatal occurring after thoracocentesis. The frequency of major bleeding in patients above 70 years was 8% in females and 4% in males, in those below 70 years it was 0.5%; 22 patients (8%) had minor bleeding. Control phlebography after one week revealed completely cleared thrombus in 3%, partial clearance in 36%, unchanged in 39% and increased thrombosis in 22%. Dosage was significantly correlated to thrombus resolution.

Adult↗
PubMed1983

Acute damage to human endothelial cells by brief exposure to contrast media in vitro.

Cultured endothelial cells derived from human umbilical cord veins were labeled with Na2 (51Cr)O4 and exposed to pure isoiodinated contrast media or control solutions for 10 minutes to simulate the effects of intravenous injections of contrast media on the human endothelium. Metrizamide, iohexol, iopamidol, meglumine/Ca metrizoate (300 mg I/ml), meglumine/Na diatrizoate, meglumine/Na ioxaglate, and meglumine/Ca metrizoate (200 mg I/ml) were tested. Iso-osmolal mannitol solutions were used to determine the portion of injury that was due to the effects of osmolality. Up to six times more chromium-51 was released from the cultures following exposure to the two hyperosmolal ionic contrast media (meglumine/Na diatrizoate and meglumine/Ca metrizoate) than with exposure to the least toxic agent, iopamidol. The dimer ioxaglate and the three nonionic agents (iohexol, metrizamide, and iopamidol) gave a chromium-51 release rate that was almost equal to or lower than that of 0.9% saline. Follow-up of the washed cultures for 24 hours showed no residual toxic effects.

Cells, Cultured↗
PubMed1983

The usefulness of fibrin degradation products (FDP) in detection of postphlebographic thrombophlebitis.

In 8 out of 9 patients with postphlebographic thrombophlebitis (DVT), increased amounts of fibrin degradation products (FDP) were recorded on one or more occasions during six days' follow up, as compared to 20 out of 45 patients in the DVT negative group. FDP determination is insufficient as a sole parameter in identifying patients developing postphlebographic DVT.

Fibrin Fibrinogen Degradation Products↗
PubMed1982

The mechanism of angioplasty. Dilatation of iliac cadaver arteries with intravascular pressure control.

A model was developed which allows the dilatation of iliac cadaver arteries under normal blood pressure conditions (mean pressure 100 mmHg). Segments of the iliac artery were put under pressure and dilated with balloons under similar conditions as in clinical practice. Purposely oversized balloons were used because most of the arteries did not contain severely stenotic plaques and consequently the commercially available balloons had no effect because of their comparatively small diameter. In spite of the use of oversized balloons, the cadaver arteries could not be significant dilated. Rupture of the intima and media was almost invariably present. Leakage of distending fluid through the adventitia occurred commonly. The "therapeutic range" between minimal dilation and partial or total rupture in postmortem studies is small.

Adolescent↗
PubMed1982

The site of arterial wall rupture in transluminal angioplasty: an experimental study.

The site of arterial rupture following arterial balloon dilatation was studied in postmortem canine arteries. An atherosclerotic plaque was simulated by insertion of a solid nylon ball. Longitudinal tears of intima and media were produced at the level of the nylon ball. The site of arterial rupture can therefore be predicted if localized changes of wall strength can be neglected. On the other hand, the site of arterial rupture in clinical cases will depend mainly on the consistency and tensile strength of the diseased artery.

Angioplasty, Balloon↗
PubMed1981

Postphlebographic thrombosis: a double-blind study with methylglucamine metrizoate and metrizamide.

A double-blind, randomized study was conducted in 170 patients to compare the effects of two hypertonic contrast media in phlebography of the leg: one was ionic [methylglucamine metrizoate (Isopaque Cerebral, 280 mg I/mI)] and the other nonionic [metrizamide (Amipaque, 280 mg I/mI)]. Ninety patients who showed no venous thrombosis on phlebography were followed up for 6 days with the 125I-fibrinogen uptake test, and those with abnormal scans were referred for further phlebography. Eleven of the 42 patients in the Isopaque group (26%) demonstrated signs of fresh venous thrombosis, compared with only 2% (1/48) in the Amipaque group, a highly significant difference (p less than 0.001). Six patients in the Isopaque group (14%) demonstrated clinical signs of superficial thrombophlebitis, which was not seen in the Amipaque group. Anticoagulant therapy is effective in preventing contrast-induced thrombophlebitis.

Adult↗
PubMed1980

A method to analyze the motion of the endocardium during contraction.

Regional segmental wall motion analysis assumes a linear or radial grid system. In this study, motion patterns of points on the canine endocardium were evaluated. Radiopaque endocardial and epicardial markers were inserted along the anterior and posterior descending coronary arteries. Postoperative cine radiography showed that the endocardial markers did not move along either linear or radial grids. The endocardial and epicardial markers were shown to have different patterns of movement.

Animals↗
PubMedDate not supplied

In vitro evaluation of a new temporary venous filter: the Spring filter.

PURPOSE: To evaluate in vitro the function efficacy of a new variable-sized, temporary venous filter, the Spring filter (SF). METHODS: The SF was tested in a flow phantom, using flexible, thin-walled polyethylene tubes 12, 14, and 16 mm in diameter to simulate veins. Clots of three sizes were used: 6 x 10 mm, 6 x 20 mm, 9 x 20 mm. Filter deployment was performed, ensuring that its functional diameter after placement was a predetermined multiple of the radius 'r' of the tube: 3.0r, 2.8r, 2.6r, 2.4r. The terminal coil was visually examined for changes in configuration. Clot retention by the filter for a period of 3 min was recorded as a success. The baseline intraluminal pressure and the maximum pressure reached after clot introduction were recorded. The trapping ability was calculated from the results for 10 clots. The effect of the following parameters on filter function were studied: size of embolus, caliber of simulated vein, and functional diameter of filter. RESULTS: The filter configuration was stable. Not a single instance of axial tilting occurred on deployment. Functional diameter was the major determinant of filter function. One hundred percent of clots were trapped irrespective of clot size and tube caliber when the functional diameter was 3.0r. Only 73% (95% confidence interval (CI): 57% - 88%) and 77% (95% CI: 61% - 92%) of small emboli were held up by the filter when the functional diameters were 2.6r and 2.4r, respectively (p = 0.0001). A significant reduction in clot trapping was encountered even with medium clots when the functional diameter was 2.4r (p = 0.02). CONCLUSION: Against the background of available data on retrievable vena caval filters, the current model of SF warrants further investigation.

Equipment Design↗
PubMedDate not supplied

Animal model of acute deep vein thrombosis.

PURPOSE: To develop an animal model of acute deep vein thrombosis (DVT). METHODS: In part I of the study nine juvenile domestic pigs were used. Each external iliac vein was transluminally occluded with a balloon catheter. Thrombin was infused through a microcatheter in one leg according to one of the following protocols: (1) intraarterial (IA): 1250 U at 25 U/min in the common femoral artery (n = 3); (2) intravenous (IV): 5000 U in the popliteal vein at 500 U/min (n = 3), or at 100 U/min (n = 3). Saline was administered in the opposite leg. After the animals were killed, the mass of thrombus in the iliofemoral veins was measured. The pudendoepiploic (PEV), profunda femoris (PF), and popliteal veins (PV) were examined. Thrombosis in the tributaries of the superficial femoral vein (SFVt) was graded according to a three-point scale (0, +, ++). In part II of the study IV administration was further investigated in nine pigs using the following three regimens with 1000 U at 25 U/min serving as the control: (1) 1000 U at 100 U/min, (2) 250 U at 25 U/min, (3) 250 U at 6.25 U/min. RESULTS: All animals survived. In part I median thrombus mass in the test limbs was 1.40 g as compared with 0.25 g in the controls (p = 0.01). PEV, PFV and PV were thrombosed in all limbs infused with thrombin. IV infusion was more effective in inducing thrombosis in both the parent veins (mass 1. 32-1.78 g) and SVFt (++ in 4 of 6 legs), as compared with IA infusion (mass 0.0-1.16 g; SFVt ++ in 1 of 3 legs). In part II thrombus mass in axial veins ranged from 1.23 to 2.86 g, and showed no relationship with the dose of thrombin or the rate of infusion. Tributary thrombosis was less extensive with 250 U at 25 U/min than with the other regimens. CONCLUSION: Slow distal intravenous thrombin infusion in the hind legs of pigs combined with proximal venous occlusion induces thrombosis in the leg veins that closely resembles clinical DVT in distribution.

Animals↗