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Biomedical subjects

M S Hansen

Publications and source records attributed to M S Hansen.

At least 55 records · Page 3Linked to original sources

Fibrinogen Copenhagen; an abnormal fibrinogen with defective polymerization and release of fibrinopeptide A, but normal adsorption of plasminogen.

A qualitatively abnormal fibrinogen was detected in the plasma of a 53 year old woman with severe arterial thrombotic disease. The concentrations of plasma fibrinogen and serum fibrinogen related material were normal. The abnormal fibrinogen was electrophoretically normal. The defects detected were an abnormality of polymerization of fibrin monomers and a decreased rate of release of fibrinopeptide A. The absorption of radiolabelled partially degraded plasminogen on to fibrin prepared from purified fibrinogen Copenhagen was normal.

Adsorption↗

Plasma protein regulation of platelet function and metabolism.

This reviews summarizes our evidence suggesting that the plasma protein enviroment influences platelet aggregation potential and metabolic activity. Cationic proteins are capable of restoring the aggreation potential of washed human platelets. The aggregation restoring effect of gamma globulin is inhibited by more anionic proteins in subfractions of Cohn fraction IV and fractions V and VI. Artificial enhancement of the net negative charge of plasma proteins through acylation produces derivatives capable of inhibiting platelet rich plasma. The oxygen consumption of washed human platelets is lower than in platelet rich plasma while the lactate production is identical. Autologus plasma, albumin or IgG immunoglobulin restores the oxygen consumption of washed platelets to values comparable to those obtained for platelet rich plasma, while the lactate production is unaffected. Fibrinogen on IgA myeloma protein increases the lactate production, but not the oxygen consumption. Cyclic AMP levels are considerably lower in washed platelets than in platelet rich plasma. Gamma globulin and albumin causes a futher decrease, which is progressive with time. Fibrinogen causes no change in platelet cyclic AMP content. It is suggested that these observations may in part be explained by the equilibriun between anionic and cationic proteins in the platelet microenvironment. This hypothesis appears applicable in certain situations.

Adenosine Diphosphate↗

Thrombotic thrombocytopenic purpura: treatment with a combination of antiplatelet drugs.

Thrombotic thrombocytopenic purpura (TTP) is a rare disease with a vary high mortality. Different modalities of therapy have been tried, but often with no effect. Recently, interest has focused on drugs interfering with platelet function, though few patients have received antiplatelet drugs as the only therapy. We describe a patient with TTP, who recovered completely on a combination therapy with dextran, aspirin and dipyridamole.

Aspirin↗

The effect of acetyl salicylic acid and dipyridamole on thromboembolic complications in splenectomized patients with myelofibrosis.

The effect of combined treatment with acetyl salicylic acid and dipyridamole on thrombic phenomena was studied in splenectomized patients with an aggressive form of myelofibrosis. 3 of these patients had thrombotic episodes, shortened platelet survival and an abnormal platelet aggregation pattern. The treatment with antiplatelet drugs resulted in a decreased platelet utilization as evidenced by clinical improvement and an increasing platelet concentration.

Aged↗

Megathrombocytopenia associated with glomerulonephritis, deafness and aortic cystic medianecrosis.

Macrothrombocytopenia associated with glomerulonephritis and deafness has only been reported in a few patients since it was first described in 1972. We present a patient with macrothrombocytopenia, glomerulonephritis, progressive uraemia and progressive sensorineural deafness associated with cystic medianecrosis of the ascending aorta and malformation of the aortic valves. The patient had consistently low platelet counts but no clinical signs of a defect haemostasis. The giant platelets were characterized by their size, averaging 11 micron in diameter, elaborate maze-like membrane formations, abundance of microtubules, and the total absence of very dense granules.

Adolescent↗

Analysis of soluble fibrin complexes by agarose gel chromatography and protamine sulfate gelation.

The molecular makeup of soluble fibrin complexes was studied by gel exclusion chromatography using radio-labelling to characterize individual components in protein mixtures. Products of limited plasmin degradation of fibrinogen and mixtures of fibrinogen and "early" fibrinogen digests formed high molecular weight soluble fibrin complexes upon incubation with thrombin. Purified, nonclottable fragment Y did not incorporate into soluble fibrin complexes, nor could we demonstrate incorporation of fragments D and E as previously described from our laboratory. Thus, under the conditions of these experiments, soluble fibrin complexes have two identifiable components, fibrin monomer and clottable fragment X monomer, although incorporation of native fibrinogen or fragment X unreacted by thrombin into soluble fibrin complexes cannot be excluded. Individual fractions of thrombin-treated early fibrinogen digests isolated by agarose gel chromatography were treated with protamine sulfate at 37 degrees C resulting in precipitation-gelation of greater than 90 per cent of high molecular weight soluble fibrin complexes; whereas, less than 10 per cent of lower molecular weight fibrinogen degradation products precipitated by protamine sulfate. These findings do not support the widely held concept that soluble fibrin complexes incorporate nonclottable degradation products of fibrinogen proteolysis, nor do they support the notion that the so-called paracoagulation reaction induced by protamine sulfate results from the splitting of complexes between fibrin monomer and nonclottable fibrinogen degradation products.

Binding Sites↗

Enhancement of blood coagulation by soluble fibrin complexes.

We have detected a species of soluble fibrin complexes with significant biological properties. Agarose gel chromatography of normal plasma or purified fibrinogen previously incubated with small amounts of thrombin revealed the presence of a species of high molecular weight soluble fibrin complexes, which contained only small quantities of fibrinogen by immunological assays but which exhibited enhanced sensitivity to thrombin. In addition, these complexes substantially shortened the thrombin-clotting time of normal plasma and enhanced the resistance of normal plasma to heparin action. Similar thrombin-sensitive soluble fibrin complexes were demonstrated in vivo in rabbits for up to 10 min after the infusion of 50 U of thrombin. Thrombin-sensitive soluble fibrin complexes were also demonstrated in 3 of 12 patients with documented thromboembolic disease and in 2 of 20 patients after major surgery. High molecular weight soluble fibrin complexes, which exhibit enhanced thrombin sensitivity and which are capable of increasing the rate of normal fibrinogen-to-fibrin conversion by thrombin, may appear consequent to clinical thrombosis and situations involving trauma (e.g., major surgery). Such soluble complexes, although they have no proven role in the primary pathogenesis of intravascular thrombosis, may contribute to a temporary "hypercoagulable state" and may accelerate the build-up and extension of already existing thrombotic deposits.

Blood Coagulation↗

Complexity of care and mental illness in medical inpatients.

We investigated the complexity of medical inpatient care to learn it was associated with the presence and type of mental disorders, and with emotional distress and somatization. Six indicators of care complexity, including length of stay (LOS), were assessed for 294 consecutive medical inpatients. Patients rated their own health and physical disability, and medical consultants assessed them for chronic and life-threatening diseases. A subsample of 157 patients was assessed for ICD-10 psychiatric diagnoses by means of an extensive semi-structured interview known as Schedules for Clinical Assessment in Neuropsychiatry (SCAN). With a few exceptions, the indicators of complexity of care were not statistically significantly associated to ICD-10 mental disorders; psychological distress, measured by the SCL-8 rating scale; or somatization, measured by the Whiteley-7 rating scale. On the other hand, four of six complexity indicators were significantly associated with self-rated physical disability or health, or both, when controlling for the severity of the medical condition. In conclusion, complexity of care, including LOS, was substantially associated with the patient's own health perception but only marginally with the presence of mental illness. This is noteworthy, as previously published results concerning the same patients have shown a clear association of mental illness with utilization of admissions to nonpsychiatric departments, and with utilization of primary care resources.

Adolescent↗

Feasibility and patient tolerance of a novel transrectal ultrasound hyperthermia system for treatment of prostate cancer.

This report describes patient tolerance and toxicity of a transrectal ultrasound hyperthermia system used with external beam radiation therapy in treatment of locally advanced prostate cancer. Nine patients with clinical T2B-T3B (4th edition AJCC criteria) disease received external beam radiation therapy, with two hyperthermia treatments scheduled at least 1 week apart during the first 4 weeks of radiation. Five patients also received hormonal therapy. Interstitial and anterior rectal wall thermometry were performed. Median temperature for each treatment (T50) was 40.8 degrees C and mean CEM T90 = 43 degrees C was 3.4 min. Rectal wall temperature was maintained at < or = 40 degrees C. Treatment duration was limited in three of 17 sessions due to positional discomfort which was alleviated with light IV sedation and use of a 'New Life' mattress (Comfortex, Inc. Winoba, MN, USA). Acute toxicity was limited to NCI common toxicity criteria grade 1 and no excess toxicity was noted with full course radiation therapy +/- hormonal therapy. These findings are consistent with those reported in a previous phase I trial assessing this device. Given the favourable toxicity profile demonstrated to date, modification of treatment parameters for this ongoing phase II study have been instituted that should further the efficacy of transrectal ultrasound hyperthermia for treatment of prostate cancer.

Aged↗