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S Madsen

Publications and source records attributed to S Madsen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Stimulus-dependent central processing of auditory stimuli: a PET study.

Positron emission tomography (PET) was used to investigate the neural systems involved in the central processing of different auditory stimuli. Noise, pure tone and pure-tone pulses, music and speech were presented monaurally. O-15-water PET scans were obtained in relation to these stimulations presented to five normal hearing and healthy subjects. All stimuli were related to a basic scan in silence. Processing of simple auditory stimuli, such as pure tones and noise, predominantly activate the left transverse temporal gyrus (Brodmann area [BA] 41), whereas sounds with discontinued acoustic patterns, such as pure-tone pulse trains, activated parts of the auditory association area in the superior temporal gyri (BA 42) in both hemispheres. Moreover, sounds with complex spectral, intensity, and temporal structures (words, speech, music) activated spatially even more extensive associative auditory areas in both hemispheres (BA 21, 22). PET has revealed a remarkable potential to investigate early central auditory processing, and has provided evidence of the coexistence of functionally linked, but individually active parallel and serial auditory networks.

Acoustic Impedance Tests↗
PubMed1998

[Constrictive pericarditis illustrated by an unusual case report].

Constrictive pericarditis is an uncommon condition. Previously, tuberculosis or other bacterial infections were prevalent causes, often with prominent pericardial calcification. Presently, many patients with constrictive pericarditis of other aetiologies have lesser degrees of structural changes in the pericardium. We report on a case with severe symptoms where the correct diagnosis was elusive because of absent or minimal preoperative pericardial pathology. The clinical, echocardiographic and haemodynamic features of constrictive pericarditis are reviewed. We recommend thorough echocardiographic evaluation of central haemodynamics in patients with symptoms of heart failure when the aetiology is not readily apparent (e.g. previous myocardial infarction dilated cardiomyopathy or valvular disease.

Aged↗
PubMed1998

[Sotalol--atrial fibrillation, reduced renal function and sudden death].

Sotalol is a betablocker with additional antiarrythmic properties. Its pharmacokinetic properties may lead to increased serum levels of the drug in patients with reduced kidney function. We report on a case in which kidney failure in a patient using sotalol for paroxysmal atrial fibrillation gave rise to torsade de pointes ventricular tachycardia and, eventually, sudden death. Gradual prolongation of the QT interval suggested an overdose of sotalol. Sotalol has been commonly used in cases of angina pectoris and hypertension. The recently published SWORD study has, however, changed the indications for its use, and sotalol should now only be used in cases of severe supraventricular and ventricular arrythmias.

Acute Kidney Injury↗
PubMed1998

[Sherlock Holmes as amateur physician].

The medical literature contains numerous articles dealing with Sherlock Holmes and his companion Dr. Watson. Some of the articles are concerned with the medical and scientific aspects of his cases. Other articles adopt a more philosophical view: They compare the methods of the master detective with those of the physician--the ideal clinician should be as astute in his profession as the detective must be in his. It this article the author briefly reviews the abilities of Sherlock Holmes as an amateur physician. Often Holmes was brilliant, but sometimes he made serious mistakes. In one of his cases (The Adventure of the Lion's Mane) he misinterpreted common medical signs.

Books, Illustrated↗
PubMed1997

[Statins--the pattern of adverse effects with empahsis on mental reactions. Data from a national and an international database].

We report on adverse drug reactions to statins recorded internationally and in Norway. The use of HMG-CoA reductase inhibitors (statins) has increased with a factor of 30 in Norway over the period 1989-96. Recently published clinical trials conclude that statins are safe; adverse drug reactions being infrequent and non-serious. The reactions observed are mostly increased hepatic enzymes and myopathy. Data from the Norwegian spontaneous reporting system, and from WHO's international database covering the period of 1988-95, includes reports of adverse drug reactions relating to other organ systems, such as the nervous system, the gastrointestinal tract, skin and cardiovascular organs. Psychiatric disorders represent 15% of the reactions to statins in the Norwegian database. Reactions include aggression, nervousness, depression, anxiety, sleeping disorders and impotence. The pharmacological mechanisms are not elucidated, but may be an effect of falling serum cholesterol.

Adult↗
PubMed1997

[Treatment of hypercholesterolemia with statins].

The etiology of arteriosclerosis is a complicated interaction of many factors, among which aberrations in the cholesterol metabolism appear to play an important role. Several studies have shown that lipid-lowering therapy with statins improves survival and reduces complications in patients with coronary artery disease. Until recently, the role of cholesterol-lowering in patients with elevated cholesterol, but without diagnosed coronary disease, was not clear. New studies suggest that men in this group may benefit from treatment with statins. This article focuses on some of the problems connected with the widespread use of statins, namely: proper selection of patients, the safety of long-term statin therapy, economics, and the need for additional therapy and for the continuation of population-based general measures.

Adult↗
PubMed1996

A simple filter-paper technique allows detection of mucosal cytokine levels in vivo in ulcerative colitis. Interleukin-1 and interleukin-1-receptor antagonist.

A simple filter-paper method for in vivo assessment of cytokines in intestinal mucosa of patients with ulcerative colitis (UC) was developed and evaluated. Twenty-eight patients were included. Twenty-three patients had ulcerative colitis (UC) and five irritable bowel syndrome (IBS). Inflammation was assessed endoscopically. Through a rectoscope, filter paper was applied to the macroscopically most inflamed area of the rectal mucosa until soaked. The filter paper was transferred to a buffer solution, and IL-1 beta and IL-1ra were assessed using ELISA. Positive correlations between endoscopic grading and In(IL-1 beta) (P < 0.0001) and In(IL-1ra) (P < 0.001) and a negative correlation between endoscopic grading and In(IL-1ra /IL-1 beta) (P < 0.02) were found. In measurements during and after a flare-up no significant change in IL-1ra but a significant decrease in IL-1 beta was detected, which is in agreement with investigations on biopsies. In conclusion, the filter-paper technique is an easily applicable, low-risk method that provides a means of monitoring cytokines in vivo in UC.

Colitis, Ulcerative↗
PubMed1996

Factors affecting the biodegradation of toluene in soil.

The biodegradation of toluene in soil microcosms was examined in order to identify the physical, chemical, and biological factors which determine the fate and lifetime of organic chemicals in soils. Toluene degradation rates were proportional to the initial substrate concentration and these rates reached a maximum at a concentration of 200 micrograms/g. No degradation occurred above this concentration presumably due to the toxicity of the hydrocarbon to the soil microorganisms. Small differences were observed in the degradation rates in soils at different moisture content. However, the availability of water in soil appeared to limit toluene degradation only at a very low water content. The lifetime of toluene in soil was also related to the initial level and activity of the soil microorganisms. Toluene was metabolized rapidly in those soils which initially contained high levels of degrading microorganisms. Furthermore, exposure of the soil to toluene resulted in an increase in the number of degrading organisms. The lack of inorganic nutrients such as nitrogen prevented complete degradation of toluene in a clay soil which contained high levels of degrading microorganisms. The biodegradation of organic chemicals in soil is not an intrinsic property of the molecule and cannot be predicted without first delineating the environment in which it is found. The biodegradation of a compound is defined by the biological, physical, and chemical characteristics of the soil environment. The lifetime of a chemical in soil results from a combination of all three of these parameters.

Bacteria↗
PubMed1995

Effects of combined radiofrequency and direct current energy catheter ablation on ventricular myocardium in pigs.

When radiofrequency catheter ablation of ventricular arrhythmias is unsuccessful, an option may be to combine it with direct current energy. We therefore investigated the effects of such a combination. Radiofrequency energy was delivered in a bipolar or unipolar fashion to the left and right ventricles through an ablation catheter with a tip electrode 2 mm long, using a temperature-guided radiofrequency generator. Radiofrequency ablation was followed by a single cathodal direct current shock (66 J) with the ablation catheter positioned similarly in six closed-chest pigs. In a control group (six animals) only direct current ablation was performed, with one or two energy applications (66 J) in each ventricle. Two of six animals in the radiofrequency/direct current group died due to perforation in the follow-up period, 1 and 3.5 h after the direct current ablation, respectively. Gross pathological examination of the hearts revealed transmural lesions in all animals. In the radiofrequency/direct current group four lesions were perforated, three of which were located in the left ventricle. There was a significant increase in the number of perforations in the radiofrequency/direct current group compared to the control group, where perforation was never observed. Haemorrhagic pericardial fluid was found in five of the six animals in the radiofrequency/direct current group compared to none in the control group. These findings show that myocardial ablation with radiofrequency energy followed by direct current energy in the same session may have a high complication rate.

Animals↗
PubMed1994

Power and temperature guided radiofrequency catheter ablation of the right atrium in pigs.

The aim of the present study was twofold: to assess the safety of ablating the atrial free wall using RF current; and to assess the effect of a single dose of intravenous heparin followed by aspirin once daily to prevent thrombus formation after RF ablation. Temperature and power guided catheter ablation were evaluated. Twenty pigs were randomized to power or temperature guided unipolar RF catheter ablation. Ten animals received a bolus of heparin (150 U/kg) followed by 150-mg aspirin daily, and ten served as controls. A mid-sternal thoracotomy was performed 5-7 days later. The ability of a lesion to resist an increased transmural atrial pressure was examined by inflating a cuff around the pulmonal artery. Transmural lesions were found in all animals. Right atrial pressure was increased from 5 to 30 mmHg with no sign of perforation. In 11 of 20 (55%) animals, 1-3 lesions were found in the lungs (diameter 4-18 mm). The localization of these lesions corresponded to the lesions in the atria. There were no differences in the energy delivery modes with regard to the number of animals with lung lesions. Lesions with thrombus formation were found in four animals in the heparin/aspirin group and in nine animals in the control group. The incidence of thrombi was significantly smaller in the treatment group. There were no differences between temperature and power guided catheter ablation with regard to the size of the atrial lesions or to the incidence of thrombus formation. Transmural lesions induced in the right atrium by RF energy are resistant to increases in transmural pressure. However, lung tissue overlying the ablated target may be injured by the RF energy delivered. The combination of a single dose intravenous heparin followed by aspirin daily may reduce the incidence of thrombus formation.

Animals↗
PubMed1993

[Physicians as crime writers and literary detectives].

Doctors have played an important role in the development of the crime story--both internationally and in Norway. This paper reviews the biographies of some well-known writers and their sleuths--from Sir Arthur Conan Doyle to contemporary Norwegian authors.

Crime↗