Search PubMed⌕ Search

Biomedical subjects

J Gormsen

Publications and source records attributed to J Gormsen.

At least 19 recordsLinked to original sources
PubMed1988

Analysis of velocity in the ascending aorta in humans. A comparative study among normal aortic valves, St. Jude Medical and Starr-Edwards Silastic Ball valves.

To analyze velocity spectral energy distribution in humans, blood velocities were recorded by means of hot-film anemometry at 41 predetermined measurement points in the cross-sectional area of the ascending aorta approximately 6 cm downstream of the aortic valves. Measurements were made in 8 patients with normal aortic valves, in 4 after insertion of a St. Jude Medical (SJM) aortic valve and in 3 after insertion of a Starr-Edwards Silastic Ball (SSB) aortic valve. Data analysis based on Fast Fourier Transform demonstrated that turbulence energy was lower in patients with normal aortic valves than in patients after insertion of an artificial valve in the aortic position and probably more pronounced after SSB valves than after SJM valves. The spatial distribution of the turbulence energy above 100 Hz was more irregular than corresponding laminar velocities previously presented. The VER100 (Velocity Energy Ratio at 100 Hz, i.e. the velocity energy above 100 Hz divided by the total velocity energy) proved useful for evaluating differences in flow disturbances downstream of different aortic valves. The mean VER100 in the three categories of patients were respectively 0.3, 1.4, and 2.1%.

Adult↗
PubMed1987

Three-dimensional visualization of axial velocity profiles downstream of six different mechanical aortic valve prostheses, measured with a hot-film anemometer in a steady state flow model.

Hot-film anemometry was used for in vitro steady-state measurements downstream of six mechanical aortic valve prostheses at flow rates 10, 20 and 30 l.min-1. Three-dimensional visualizations of velocity profiles at two downstream levels were made with the valves rotated 0 and 60 degrees in relation to the sinuses of valsalvae. The velocity fields downstream of the disc valves were generally skew with increasing velocity gradients and laminar shear stresses with increasing flow rates. Furthermore, increased skewness of the velocity profiles was noticed when the major orifices of the disc valves were towards the commissure than when approaching a sinus of valsalvae. The velocity profiles downstream of the ball valve were generally flat but with considerably more disturbed flow, consistent with the findings in turbulent flow.

Aortic Valve↗
PubMed1986

Effect of metoprolol and propranolol on platelet aggregation and cAMP level in hypertensive patients.

Ten patients with uncomplicated moderate essential hypertension were recruited to evaluate the effect of the non-selective beta-blocker propranolol and the beta 1-selective beta-blocker metoprolol on platelet aggregation and cAMP formation. Five patients began treatment with propranolol 80 mg b.i.d. and 5 with metoprolol 100 mg b.i.d., and after 2 weeks the treatments were exchanged. ADP- and adrenaline-induced platelet aggregation and the basal level of platelet cAMP were measured at the end of each treatment period. Platelet aggregation was tested turbidometrically, using the threshold value for irreversible aggregation, and cAMP measurements were performed using a protein-binding assay. Both ADP and adrenaline threshold values were significantly lower after propranolol than after metoprolol. The basal cAMP level was lower during propranolol than metoprolol treatment. The results indicate that platelet aggregation and basal cAMP level are influenced by beta-blockers in proportion to their affinity to different beta-adrenoceptors. This may be of value in the beta-blocker treatment of patients at high thrombotic risk.

Adenosine Diphosphate↗
PubMed1986

Hemophilic patients with an inhibitor to factor VIII treated with high dose factor VIII concentrate. Results of a collaborative study for the evaluation of factor VIII inhibitor titer, recovery and half life of infused factor VIII.

The long term treatment of hemophilic patients with an inhibitor to Factor VIII has been difficult although some success with immunosuppressive agents has been reported. Eighteen hemophilic patients, mainly from Bonn in Germany, but also from other countries, have completed a high dose Factor VIII treatment in an attempt to reduce their inhibitor titer and induce "immune tolerance" to Factor VIII. Plasma samples from the 18 patients collected before and after infusion of 50 units Factor VIII/kg body weight were sent to five laboratories to evaluate inhibitor titer, Factor VIII recovery and half life. This collaborative study demonstrated a close correlation from one laboratory to another concerning inhibitor titration and Factor VIII recovery. The conclusion of the study is that all patients treated with this protocol showed an undetectable or low inhibitor titer against Factor VIII indicating that they can be efficiently treated with Factor VIII.

Adolescent↗
PubMed1985

The effect of ticlopidine on platelet functions in acute myocardial infarction. A double blind controlled trial.

A group of 43 consecutive patients with AMI were randomized to treatment with a novel platelet inhibitor, ticlopidine, or placebo in a double blind study. Treatment was started within 12 hr after onset of precordial pain. Patients who had taken drugs with known platelet inhibitory effect prior to the onset of therapy were excluded. Platelet survival time (PS) was measured 24-36 hr after onset of precordial pain and after 3 months of treatment in both groups. In the early phase of AMI CK-MB and ASAT were taken twice daily for estimation of infarction size. Platelet function, coagulation factors and fibrinolysis parameters were followed sequentially for 21 days and repeated after 3 months. In the placebo group a significant reduction in PS (5.62 +/- 1.63 S. D. days) was measured in the acute phase of AMI compared to PS 3 months after infarction (8.03 +/- 1.20 S.D. days). In the ticlopidine group PS was normal during the acute phase (8.35 +/- 1.82 S.D. days). After 3 months of treatment PS was normal in both groups. During the first two weeks after AMI significant changes in coagulation parameters and fibrinolysis indicated an increased risk of thrombosis in both groups. These parameters were unaffected by the platelet inhibitory therapy. Estimated by peak CK-MB and ASAT, infarction size was significantly reduced in the ticlopidine group.

Adult↗
PubMed1985

Effect of specific thromboxane-synthetase inhibition on thromboxane and prostaglandin synthesis in stable angina induced by exercise test.

14 patients with effort induced angina pectoris were treated with a specific TxB2 inhibitor Dazoxiben or verapamil for two weeks with a wash-out period of 14 days between the two regimens. A sub-maximal bicycle test was performed before treatment and at the end of each treatment period. The bicycle test induced a significant increase in serum TxB2 in patients without treatment and during verapamil therapy. This increase was significantly inhibited by Dazoxiben treatment. No alterations in plasma TxB2 or 6-keto-PGF1 alpha were observed on either regimen. Dazoxiben had no clinical effect, while verapamil caused a highly significant prolongation of exercise time.

Aged↗
PubMed1985

Verapamil induced increment of oxygen extraction in the arteriosclerotic limb.

The acute effect of intravenously administered verapamil (0.08 mg X kg-1 body weight, mean dose 5.1 +/- 0.7 mg) on oxygen exchange and arterial blood flow (measured electromagnetically) of the lower limb was studied during reconstructive arterial surgery in 17 patients with obliterative arterial disease of the lower limbs. Verapamil increased oxygen extraction in the diseased leg by 12% (from a median value of 28.3 to 31.6 ml X litre-1, p less than 0.01) whereas it had no effect on arterial blood flow. The increment of oxygen extraction after drug administration correlated negatively with the walking distance of the patients (r = 0.69, p less than 0.01). Systolic and diastolic blood pressure decreased significantly by 10% and 6%, respectively, whereas heart rate remained unchanged after the administration of verapamil. The results suggest that verapamil might be beneficial in the treatment of patients with intermittent claudication, despite the fact that no vasodilatation was seen after the drug.

Aged↗
PubMed1984

Alterations in T-lymphocyte subsets among Danish haemophiliacs: relation to source of factor VIII preparations and high dose factor VIII treatment.

Screening of 43 healthy Danish haemophiliacs revealed a significantly lower helper/suppressor (H/S) ratio than in controls. 8 of the haemophiliacs had an H/S ratio less than or equal to 1.0. A significant negative correlation occurred between the total lifetime factor VIII treatment and the H/S ratio. However, high-dose factor VIII treatment given to patients with antibodies against factor VIII was not associated with immunological abnormalities. Children had a significantly higher H/S ratio than the adult haemophiliacs. Patients exclusively treated with Danish cryoprecipitate during the last year had a significantly higher H/S ratio than patients receiving preparations from other sources. This difference might, however, be explained by lower age and lower total lifetime dose in the group receiving Danish preparations. Haemophiliacs treated with American preparations did not differ immunologically from those treated with preparations of other origin. Total serum IgG was increased in 23% of the patients. This parameter was negatively correlated with the H/S ratio. The possible relation of the observed immunological alterations among otherwise healthy haemophiliacs to the acquired immune deficiency syndrome warrants further attention.

Adolescent↗
PubMed1983

Prognostic value of in vitro measurements of platelet aggregability and fibrinolytic activity in patients with reversible cerebral ischemic attacks.

Platelet aggregability and fibrinolytic activity were studied repeatedly in 83 patients with reversible cerebral ischemic attacks over a median follow-up period of 26 months. Platelet hyperaggregability, defined as in vitro secondary aggregation obtained by adenosine diphosphate concentration less than or equal to 1 mumol/l, was demonstrated in 36.1% or the patients examined 5-8 days after the attack, but only in 6% of age- and sex-matched blood donors (p less than 0.001). Fibrinolytic activity was reduced in 57.8% of the patients, as compared with 20.5% of the controls. At the time of follow-up only 8% of the survivors showed platelet hyperaggregability, whereas the fibrinolytic activity was still reduced in 44.4%. Over the observation period 21.7% of the patients had a stroke or died. No significant correlation was found between abnormalities of platelet aggregability or of fibrinolytic activity, when observed 5-8 days after the ischemic episode, and the subsequent risk of stroke or death. It is concluded that in patients with recent cerebral ischemic attacks the demonstration of platelet hyperaggregability or reduced fibrinolytic activity appears to be without prognostic significance.

Adult↗