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Biomedical subjects

E Pedersen

Publications and source records attributed to E Pedersen.

At least 37 records · Page 2Linked to original sources
PubMed1990

Electronic determination of centres of rotation produced by orthodontic force systems.

A strain gauge measurement device with low force clip gauges, for measurement of initial tooth displacement in two dimensions has been developed. An experimental model simulating a maxillary central incisor is loaded with different known and controlled force systems. The resulting tooth displacements are described by the position of the centre of rotation and the generated angle of rotation for the total tooth movement. The effect of a single force, a moment, and force-moment combinations producing different moment to force ratios were studied. From these results the required force system needed to produce tooth movements with different centres of rotation for a central incisor of average root length are calculated. Furthermore, the model allows us to measure the accuracy of the measuring device by comparing results to analytical and laser holographic data, obtained on similar models. Some preliminary measurements and results, using human autopsy material are presented.

Adult↗
PubMed1990

Comparison of induction with and first hour of recovery from brief propofol and methohexital anesthesia.

Anesthesia and recovery during the first hour after propofol and methohexital anesthesia for termination of pregnancy, lasting about 12 min, were compared, the latter in a double-blind manner by means of psychomotor tests (coin counting and continuous auditory reaction time). Muscle movements and hiccups were seen significantly more frequently during methohexital inductions. No differences were seen regarding pain at the site of injection or apnea between the groups. At 15 min after the last dose of anesthetic, recovery after methohexital was ahead of that after propofol, but after 1 h, psychomotor performance was better in the propofol group. Side-effects during recovery were few, and incidences did not differ significantly. Although the difference in reaction time test was significant, it was hardly large enough to be of any clinical importance. Both drugs are useful for brief outpatient anesthesia, but smoother induction gives propofol an edge over methohexital.

Abortion, Induced↗
PubMed1989

Endogenous nitrosation in relation to nitrate exposure from drinking water and diet in a Danish rural population.

Increasing levels of nitrate in drinking water is of concern due to the possibility of an associated increase in long-term exposure to endogenously formed carcinogenic N-nitroso compounds. Excretion of N-nitrosoproline in 12-h overnight urine after intake of 500-mg L-proline was used to quantify the rate of endogenous nitrosation in 285 individuals in an area in northern Denmark with large variation in nitrate concentration of the drinking water. Nitrate intake was measured in a 24-h duplicate diet sample. The crude association between nitrate concentration in drinking water and rate of endogenous nitrosation in individuals is only weakly positive and not quite statistically significant (P = 0.08). The risk of having detectable nitrosation increases significantly with total nitrate intake and tobacco smoking. In nonsmokers, nitrosation is determined by nitrate intake. Smokers have increased nitrosation which does not depend on nitrate intake. Effect modification through dietary factors was evaluated and indicated a protective effect of tea consumption, while the effect of eating vegetables was not clear-cut. The experimental design (12-h urine sample; proline dose taken in the evening) is likely to underestimate the effect of nitrate in drinking water relatively to nitrate in the diet.

Denmark↗
PubMed1989

Nitrate exposure from drinking water and diet in a Danish rural population.

Increasing levels of nitrate (NO3-) in drinking water in Denmark is of concern due to the possibility of an associated increase in long-term exposure to endogeneously formed N-nitroso compounds. Using a duplicate portion technique in combination with a qualitative description of diet and other background variables, the total nitrate intake in a Danish rural population and the contribution of drinking water to the total nitrate exposure is estimated. People drinking nitrate-free water have an intake of 37 mg NO3- per day. At 47 mg NO3- per litre, the exposure is increased to 89 mg, about 60% of which originates from the water. At 84 mg NO3- per litre, the daily exposure is 123 mg, 70% of which originates from the drinking water. These crude comparisons between three groups of people are supplemented with quantitative modelling of nitrate exposure at individual level. Apart from drinking water, consumption of vegetables is a major source of nitrate in this population. Using nitrate in overnight urine samples to quantify exposure is less accurate than the duplicate dietary portion technique and tends, in the present study, to underestimate the contribution of water-derived nitrate to total nitrate intake.

Adult↗
PubMed1986

Experimental electrical stimulation of the bladder using a new device.

Repeated bladder contractions were evoked during a six month period in three unanaesthetized female minipigs by using unipolar carbon fiber electrodes embedded in the bladder wall adjacent to the ureterovesical junction. In contrast to bipolar and direct bladder muscle stimulation unipolar electrodes at each ureterovesical junction evoked bladder pressure increase similar to those produced in previous investigations in dogs. Sacral nerve stimulation of S2 evoked bladder contraction at a minimal current. Microscopic examination revealed no cellular reactions to the carbon fibers but a subcutaneous reaction to the receivers was seen and was thought to be due to mechanical irritation. The clinical implication of the findings is discussed.

Animals↗
PubMed1986

Interferon induction, 2'-5' oligo A synthetase and lymphocyte subpopulations in out-patients with multiple sclerosis in a longitudinal study.

Nine patients with multiple sclerosis, four with relapsing-remitting disease, and five with chronic progressive disease, together with eight healthy control, were followed for nearly a year with monthly clinical and laboratory examinations. Alpha- and gamma-interferon was induced in lymphocytes with different viruses and PHA, no differences were found between healthy controls and multiple sclerosis patients. The alpha- and gamma-interferon induced enzyme 2'-5' oligo A synthetase in lymphocytes was found to have a tendency to be lower in multiple sclerosis patients than in healthy controls. When medians of ratios of helper/suppressor blood lymphocytes in multiple sclerosis patients were compared with healthy controls, the same results were found, although higher values of ratios were found among the patients and the highest value was found in a patient with chronic progressive disease. No correlation to disease activity could be found in interferon inductions, 2'-5' oligo A synthetase concentrations and ratios of OKT4/OKT8. In particular no change in ratio was found in relation to five exacerbations taking place in the four multiple sclerosis patients with acute relapses.

2',5'-Oligoadenylate Synthetase↗
PubMed1986

Relation between flexor spasms, uninhibited detrusor contractions and anal sphincter activity.

The time relation between flexor spasms, detrusor contractions and anal sphincter activity was recorded in a consecutive series of 111 patients with hyperreflexic bladder and flexor spasms. In 76 of the patients flexor spasms were preceded by detrusor contractions. The opposite pattern, namely detrusor contractions preceded by flexor spasms, was seen in only nine patients. The anal sphincter activity was generally increased in relation to detrusor contractions in patients with spinal lesions but decreased in patients with cerebral lesions. The treatment of flexor spasms and uninhibited detrusor contractions is discussed on the basis of this mutual relationship.

Adolescent↗
PubMed1985

Oral hygiene instruction in general dental practice by means of self-teaching manuals.

The present study evaluates the applicability of delivering oral hygiene instruction to patients in general dental practice by means of self-educational programs. Patients (55) seeking dental treatment in 3 general dental practices in Denmark were divided at random into a conventional professional instruction group (C) in which each individual received personal instruction by the dentist and a self-instruction group (S), in which the patients were given self-educational programs. In order to evaluate the effect of the 2 types of instruction, the presence or absence of dento-gingival plaque and gingival bleeding by probing was recorded prior to the instruction and after 3 and 6 months. The patient of the self-instruction group (S) answered a questionnaire about the treatment 1 week after they had received the self-instruction program. An identical improvement in oral hygiene and gingival health was recorded in both treatment groups after 3 and 6 months. This finding indicates, that the self-educational programs were as effective in changing the oral hygiene habits of the patients as was personal oral hygiene instruction by dental personnel. The answers of the patients to the post-treatment questionnaire reflected a favorable attitude towards the use of self-educational programs.

Adult↗
PubMed1984

The effect of the GABA-agonist, progabide, on stretch and flexor reflexes and on voluntary power in spastic patients.

The action of the GABA-receptor agonist, progabide , was investigated in a double-blind study with cross-over to placebo. The stretch and flexor reflexes and voluntary power were measured in 16 patients with spasticity. 2-week treatment periods were used; the median daily oral dosage of progabide was 24.3 mg/kg. The Achilles tendon (T) reflex was significantly suppressed whereas the Hoffmann (H) reflex remained unchanged: the T/H ratio was thus reduced. Hmax /M (direct motor)max ratio and the vibration-induced suppression of the T- and H-reflexes were unchanged. These findings indicate an effect of progabide on the spindles or on the controlling fusimotor system (probably acting on spinal interneurons), whereas influence on presynaptic inhibition and alpha-motoneuron excitability is unlikely. The flexor reflex threshold was increased during progabide treatment and latency at threshold decreased towards normal latency. This indicates some influence of progabide on flexor reflex activity attributed to reinforcement of action of GABAergic interneurons at the spinal level. Isokinetic measurement of voluntary power of knee extension revealed particularly good progress for the fastest movements during progabide treatment, whereas isometric measurement of sustained handgrip remained unchanged, probably reflecting a reduction of spasticity without reduction of voluntary power in non-spastic muscles.

Achilles Tendon↗
PubMed1984

The clinical effect of the GABA-agonist, progabide, on spasticity.

In a double-blind cross-over trial of two 2-week periods, the clinical effect of progabide was compared to placebo. 16 patients with spasticity in a stationary phase completed the trial. 14 had multiple sclerosis, 2 hereditary spastic paraplegia. 5 were female and 11 male. The median age was 45.5 years (range 30-62 years). The median daily dosage of progabide was 24.3 mg/kg (range 14.3-32.7 mg/kg). During progabide treatment, there was a reduction in spastic hypertonia (P less than 0.01), a suppression of tendon reflexes (patellar) (P less than 0.01), and a reduction in the frequency of flexor spasms (P less than 0.05). No significant changes in voluntary power were registered. The global clinical impression revealed a therapeutic effect in 87% of the patients (95% confidence limits 61-98%). The improvement was judged as medium or important in 50% of the patients (95% confidence limits 23-77%). No side-effects or laboratory abnormalities were seen.

Adult↗
PubMed1984

Neurourodynamic evaluation of voiding dysfunction in multiple sclerosis.

During a period of 2 1/2 years, 198 patients with definite MS were admitted to our neurological department. 88 were investigated neurourodynamically because of distinct voiding dysfunction. 73 patients showed detrusor hyperreflexia, 14 detrusor hyporeflexia or areflexia and one had normal findings. There was no obvious correlation between the occurrence of the symptoms, irritative and obstructive, and the allocation of the patients into different cystometric groups. The predominant symptom was urge incontinence. More men had been treated or were permanently treated with intravesical catheter, but mean residual urine did not show any sex difference. In 36 patients with detrusor hyperreflexia, dyssynergia was observed and was classified into 3 groups. In the group with clonic sphincter EMG activity during voiding, 5 of the patients had dyssynergia because of flexor spasms transmitted to the sphincter. In patients with dyssynergia characterized by increased sphincter activity throughout detrusor contraction, a large mean residual urine was noted, but dyssynergia did not always prevent acceptable emptying. A low rate of complication in the upper urinary tract was observed. Treatment is discussed.

Adult↗