Search PubMed⌕ Search

Biomedical subjects

B Falck

Publications and source records attributed to B Falck.

215 records · Page 12Linked to original sources
PubMedDate not supplied

The development of a multicenter database for reference values in clinical neurophysiology--principles and examples.

This paper describes the work undertaken to establish principles for the development of multicenter databases for reference values in clinical neurophysiology. The study was initiated because of interest of the involved laboratories in knowledge-based systems in electromyographic diagnosis, for which it was necessary to formalize the key concepts in the diagnostic process: diseases, pathophysiology and test results. The paper deals specifically with the structuring of results of motor and sensory nerve conduction studies.

Action Potentials↗
PubMedDate not supplied

Fluorescence of catechol amines and related compounds condensed with formaldehyde.

The reaction under mild conditions between formaldehyde and phenylalanine and phenylethylamine derivatives has been studied. When the amines included in a dried protein film were exposed to formaldehyde vapour a very intense green to yellow fluorescence was given only by those that as well as being primary amines also have hydroxyl groups at the 3 and 4 positions (3,4-dihydroxyphenylalanine, dopamine, noradrenaline). The 3-OH group seems to be essential for the reaction. The catechol amines, which are secondary amines (adrenaline, epinine), gave a much weaker fluorescence that developed more slowly. The results obtained on further examination of the reaction favour the view that the amines primarily condense with formaldehyde to 1,2,3,4-tetrahydroisoquinolines which are involved in a secondary reaction to become highly fluorescent and at the same time insoluble. This secondary reaction may be a binding to protein, an oxidation with the formation of double bonds in the heterocyclic ring, or both.

Catecholamines↗
PubMedDate not supplied

Coping with unfair treatment at work--what is the relationship between coping and hypertension in middle-aged men and Women? An epidemiological study of working men and women in Stockholm (the WOLF study).

BACKGROUND: An important hypothesis in psychosomatic medicine is that exposure to psychosocial factors that arouse anger may accelerate the onset of hypertension, particularly if the subject is not allowed to show anger or to deal constructively with the factor that evoked it. For working men and women, being treated in an unfair way at work may be crucial. The present study was designed to answer the question whether the pattern of coping - primarily directed towards the aggressor (open) or directed inwards or towards others (covert) - is associated with hypertension among working men and women. STUDY GROUP: Five thousand seven hundred and twenty working men and women aged 15-64 participated in the study. The participation rate was 76%. METHODS: The coping pattern was studied by means of a Swedish version of a self-administered questionnaire that was originally introduced by Harburg et al. RESULTS: Significant results were confined to the age group 45-54. All analyses were adjusted for age and body mass index. Smoking habits and social class had no effect on the relationships. Low scores (lowest quartile) for open coping tended to be associated with an elevated prevalence ratio (PR) of hypertension both among men (PR 1.3, 95% confidence interval, CI, 0.9-1.7) and women (PR 1.4, 95% CI 1.0-2.0). High scores for covert coping (highest quartile) were associated with an elevated PR of hypertension among men (PR 1.6, 95% CI 1.2-2.2) but not in women. If the analysis was confined to cases without medication, the relationship between a high level of covert coping and high blood pressure was still significant for men. For women, however, no significant findings were made after this operation. Accordingly, the relationship between a low level of open coping and hypertension in women was confined to women with medication. Coping patterns were correlated with psychosocial work environment factors, in particular decision latitude. CONCLUSION: In men, covert coping was associated with prevalence of hypertension. In women, there tended to be a relationship between low scores for open coping and hypertension.

Adaptation, Psychological↗
PubMedDate not supplied

Amino acids and indoleamines in the brain after infusion of branched-chain amino acids to rats with liver ischemia.

Rats with a portacaval anastomosis and ligation of the hepatic artery 2 days later were infused for 6 hr with a 10% glucose solution (group I) or the same solution combined with 0.24 M/liter branched-chain amino acids (BCAA, group II). Control animals with portacaval anastomosis and sham-operation (group III) or two sham-operations (group IV) were infused with a 10% glucose solution. The rats were killed by decapitation and indoleamines and amino acids were determined in the brain. Rats with liver ischemia were stuporous at the end of the experiment irrespective of treatment. The concentrations in the cortex of lysine, methionine, phenylalanine, threonine, alanine, glutamine, glycine, histidine, and tyrosine were significantly increased in group I compared to group IV. Infusion of BCAA to rats with liver-ischemia (group II) resulted in significantly lower concentrations of lysine, methionine, phenylalanine, threonine, histidine and tyrosine and increased concentrations of isoleucine, leucine, valine, and arginine compared to group I. The content of serotonin in the cortex and brain stem was significantly increased in group I compared with the BCAA-treated animals (group II) and the control groups III and IV. The concentrations of 5-hydroxyindoleacetic acid (5-HIAA) in the cortex and brain stem were higher in group I than in group IV. Infusion of BCAA to rats with liver ischemia normalized the concentrations of 5-HIAA in the cortex and brain stem.

Amino Acids↗
PubMedDate not supplied

Measurements of the air conditioning capacity of the nose during normal and pathological conditions and pharmacological influence.

A simple method is introduced for measuring the air conditioning capacity of the nose. A flow of 8 1/min dry air is introduced by a catheter into the nasopharynx, while 5 1/min is sucked out from the investigated nasal cavity through a psychrometer. The additional 3 1/min passes down into the pharynx, thus reducing the intermingling with expiratory air. By using CO2 as a tracer, this error was found to be maximally 15% and often about 1%. The three different enthalpy factors: increase in enthalpy of dry air, vaporization, and increase in enthalpy of water vapour, were calculated separately and the vaporization was found to be the dominant factor. The calculated total supply of humidity showed that the method presented causes at least a slight stress on the humidifying capacity. Pharmacological studies have shown that subcutaneously injected atropine decreased the total enthalpy and that of water vapour, while nasal administration of oximetazoline also decreased the total enthalpy. Nasal administration of homatropine or pilocarpine had no effect on the air conditioning. In comparison with normal subjects, those with vasomotor rhinitis had an increased enthalpy of the air, while the same enthalpy factor was reduced in cases with atrophic rhinitis. Laryngectomized patients had no significant difference in the air conditioning capacity of the nose in relation to normal subjects, while patients operated with partial maxillectomy had a considerable reduction in vaporization and total enthalpy.

Atropine↗
PubMedDate not supplied

Comparative measurements of the mucosal blood flow in the human maxillary sinus by plethysmography and by xenon.

Two different methods, one plethysmographic and one where the elimination of radioactive inert gas was measured, have been used to calculate the blood flow in the mucosa of the maxillary sinus in living man. A total of 5 persons were investigated and the mean values of the blood flow in the two methods showed a close correlation. Plethysmography is more easily performed and is therefore the preferable method to be used in studies on the physiology of the maxillary sinus.

Adult↗
PubMedDate not supplied

Evaluation of Sleep Expert--a computer-aided decision support system for sleep disorders.

Sleep Expert--a medical decision support system--is a prototype program, with knowledge based on the International Classification of Sleep Disorders (1990). The goal of this project was to evaluate Sleep Expert. In the evaluation project the knowledge of the program was first validated. Three physicians, experts in sleep disorders, were asked to choose 10 typical patient cases with sleep disorders, and to write a description. They also made a diagnosis for each case. Next, each expert made a diagnosis of the cases supplied by the other experts. They were not given the original diagnosis. The 'right diagnosis' (so-called majority agreement) was determined from the three diagnoses. Then the diagnosis of each expert was compared with the 'right diagnosis'. Two physicians, not experts in sleep disorders, were asked to make a diagnosis by using Sleep Expert. Compared to the 'right diagnosis' the diagnoses of each user (non-expert physician) were correct to 63 and 70% of cases, which is quite a good result, although it does not reach the level of the expert physicians (> or = 87%). The functionality of Sleep Expert was studied by using a limited inquiry. On the basis of the user inquiry Sleep Expert provided a useful clinical tool for non-experts.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Prognostic value of EMG in patients with lumbar disc herniation--a five year follow up.

The prognostic value of EMG in patients treated for lumbar disc herniation was evaluated in 80 patients, 55 were operated and 25 treated conservatively. All patients had an EMG examination before the initial hospitalization or operation. The patients were followed up one year and five years later. The outcome of the treatment was evaluated using a modified WHO handicap classification. The initial EMG finding had no prognostic significance in determining the outcome five years later. A normal EMG finding both at the one year and five year follow-ups was related to a good outcome. Signs of old neuropathy, large motor unit potentials and reduced interference pattern muscles were related to a poor outcome. The EMG findings predict the outcome for these patients only to a limited extent. The overall outcome seems to be influenced to a greater extent by psycho-social aspects than by qualitative aspects of the nerve root lesion detected by the EMG.

Action Potentials↗