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Biomedical subjects

J D Nielsen

Publications and source records attributed to J D Nielsen.

18 recordsLinked to original sources
PubMed1992

[Shunt-nephritis].

Infection in ventriculo-atrial shunts implanted for relief of raised intracranial pressure may, in rare cases, result in glomerulonephritis (shunt-nephritis). Most frequently, infection with low-virulent bacteria is concerned. This results in mild or subclinical symptoms with the subsequent risk that the condition is overlooked. The glomerular damage is considered to be precipitated by deposition of immune complexes in the kidneys and subsequent activation of the complement system. The renal manifestations consist of varying degrees of proteinuria, haematuria and reduction of renal function. Treatment consists of removal of the shunt. If continued relief of pressure in the ventricular system is necessary, a ventriculo-peritoneal shunt should be implanted. Normally, the prognosis of the renal disease is good. If the diagnosis and treatment are delayed, irreversible renal damage may result. Regular control of urine (proteinuria, haematuria) and blood (Hb, serumcreatinine and serum complement) are recommended in the follow up control of patients with ventriculo-atrial shunts.

Adult↗
PubMed1992

Intra-arterial thrombin activity produced by percutaneous transluminal angioplasty eliminated by segmentally enclosed thrombolysis.

We determined the specific marker of thrombin activity, fibrinopeptide A (FPA), in the vicinity of dilated sites during percutaneous transluminal angioplasty (PTA) for femoro-popliteal obstructions in 24 patients. Blood samples were drawn proximal to dilated segments from a 4F catheter inserted retrogradely in the common femoral artery and distal to dilated segments from the balloon catheter tip. Median +/- S.E. FPA concentration was 21.5 +/- 4.4ng ml-1 before PTA. Immediately after dilatation, FPA concentrations were increased to 970.0 +/- 836.9 ng ml-1 distal to dilated segments (p less than 0.00005) and to 48.5 +/- 11.4 ng ml-1 proximally (p less than 0.003). Segmentally enclosed thrombolysis (SET) was undertaken immediately after PTA, when a double balloon catheter was positioned with a balloon at each end of dilated segments. Both balloons were inflated and 5 mg recombinant tissue plasminogen activator (rt-PA) and 1000 IU heparin were enclosed in the segments for 30 min. Immediately after SET, FPA concentration distal to dilated segments was 34.0 +/- 14.2 ng ml-1 and not different from proximal concentrations found after PTA (p = 0.57). Intense fibrinolysis was indicated by significantly increased levels of cross-linked fibrin degradation products (D-dimer) for hours after SET, but FPA concentrations in peripheral blood remained near baseline values. This finding differed from increased thrombin activity found by others during systemic thrombolytic therapy. Early rethrombosis did not occur after PTA in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Standardized prothrombin time determinations and optimal anticoagulant therapy].

WHO and other international organizations have recommended the introduction of a standardized prothrombin time determination. This would allow a universal scale for the intensity of oral anticoagulation therapy to be used. A prerequisite is the use of thromboplastin, calibrated against the international reference thromboplastin, standardized methodology etc. This permits every prothrombin time determination to be expressed as International Normalized Ratio (INR). The introduction of INR facilitates the implementation of optimal oral anticoagulation as defined by larged international studies.

Anticoagulants↗
PubMed1990

[Treatment of unstable angina pectoris. A questionnaire study].

Questionnaires about therapy in unstable angina pectoris were sent to 63 Danish medical departments and were answered by 52 departments (82.5%). Nitroglycerin is commonly used but only in half of the departments is Nitroglycerin administered intravenously. Calcium-receptor-blockers are used in more departments (65%) than beta-receptor-blockers (35%) (p less than 0.05). Five departments use thrombolytic therapy along local guidelines. All recommend aspirin as prophylaxis against thrombosis and 63% recommend the therapy to be continued for life. An exercise test is always performed during hospital stay in 1/3 of the departments while the rest of the departments often wait till after the patient has been discharged. The estimate of frequency of coronary angiography varied considerably: from less than 5% to 100%. The frequency of coronary angiography was stated to be higher in Copenhagen and Aarhus (median 50%, interval 10-100%) than in the rest of the country (median 15%, interval less than 5-75%) (p less than 0.01).

Adrenergic beta-Antagonists↗
PubMed1990

[Use of fibrinolytics in the treatment of acute myocardial infarction in Denmark. A questionnaire study].

Questionnaires were sent to all Danish departments admitting patients with acute myocardial infarction (AMI) in order to investigate the attitudes of the departments to thrombolytic therapy in AMI. Two questionnaires were used: one with few questions which was answered by all 68 departments, and a more comprehensive questionnaire which was answered by 51 departments. The study shows that thrombolytic therapy now is use in all departments as opposed to 25% two years ago. In connection with introduction of thrombolytic therapy scientific studies are performed in 75% of the departments. In all departments, streptokinase (SK) is the drug of first choice and recombinant tissue plasminogen activator (rt-PA) is used in 2/3 of the departments in cases where SK-antibodies are suspected.

Denmark↗
PubMed1989

Femoral artery recanalisation with percutaneous angioplasty and segmentally enclosed plasminogen activator.

To establish whether re-occlusion of the femoral artery could be prevented, in 6 consecutive patients undergoing percutaneous transluminal angioplasty (PTA) for superficial femoral artery occlusion the recanalised segment was isolated, with a 7-French double-balloon catheter. 5 mg recombined human tissue-type plasminogen activator (rt-PA) and 1000 IU heparin were then infused into the enclosed space for 30 minutes, followed by intravenous heparin for 24 hours. At 10 and 30 days all 6 patients had evidence of recanalisation and remission of symptoms. Mean ankle-arm pressure index improved by 72% at 24 hours, by 118% at 10 days, and by 103% at 30 days after the procedure. No patients had major complications. Treatment of superficial femoral artery occlusions by PTA with rt-PA and intravenous heparin seems to prevent rethrombosis.

Aged↗
PubMed1977

ADP-induced platelet aggregation in vitro in patients with ischemic heart disease and peripheral thromboatherosclerosis.

ADP-induced platelet aggregation in vitro has been studied in 90 normal controls and in 30 patients with ischemic heart disease (IHD) and 22 with peripheral thromboatherosclerosis (PTA). The sensitivity to ADP was defined by the threshold concentration which produced secondary aggregation with an amplitude corresponding to not less than 80% of the transmission obtained by platelet-poor plasma. In the normal controls the threshold concentration was significantly lower in women aged 50 or more than in women under that age. The geometric means were lower in the patients than in the controls. Significantly lower threshold concentrations than in the corresponding age groups of controls were found in the following age groups of patients: Men and women greater than or equal to 50 years with IHD (p less than 0.005 and p less than 0.001, respectively), men and women under 50 with IHD (p less than 0.05). Men and women greater than or equal to 50 years with PTA (p less than 0.002 and p less than 0.01, respectively), men and women under 50 with PTA (p less than 0.005).

Adenosine Diphosphate↗
PubMed1977

Platelet hyperaggregability in young patients with completed stroke.

In a consecutive series of 11 young patients with clinical evidence of cerebral infarction, platelet function and plasma lipid levels were examined. The results show that increased platelet aggregability characterizes the patient group as a whole. Hyperlipidemia was frequently found, and the number of heavy smokers was high. It is suggested that all younger patients with cerebrovascular disease are examined with regard to these presumed risk factors.

Adenosine Diphosphate↗
PubMedDate not supplied

Segmentally enclosed thrombolysis in percutaneous transluminal angioplasty for femoropopliteal occlusions: a report from a pilot study.

Segmentally enclosed thrombolysis (SET) was performed immediately following 34 percutaneous transluminal angioplasties (PTAs) for femoropopliteal occlusions. The dilated segment was sealed off with a double balloon catheter, and recombinant tissue plasminogen activator (rt-PA) 1 mg/ml and heparin 200 IU/ml were injected between the balloons. The catheter was removed after 30 min and heparin treatment was continued for 24 h. Alpha-2-antiplasmin was initially reduced by 13% and normalized 2 h after SET, indicating that only small amounts of free plasmin were liberated during thrombolysis. No clinically relevant changes in plasma fibrinogen occurred. Two puncture site hemorrhages did not coincide with the coagulopathy induced by SET. One-year patency was 80%. Early rethrombosis occurred in 9% versus 41% in our previous series on standard PTA for femoropopliteal occlusions (p less than 0.001). Therefore, SET is considered beneficial in reducing the incidence of early rethrombosis.

Aged↗