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Biomedical subjects

J S Olsen

Publications and source records attributed to J S Olsen.

15 recordsLinked to original sources
PubMed1992

[Quality assurance of results of clinical chemical analyses in Danish hospital laboratories].

During the past 35 years, voluntary professional assessment of quality of the results of analyses in Danish hospital laboratories has been undertaken under the auspices of the Danish Society of Clinical Chemistry. The analytical quality of the laboratories is described by their "imprecision" and "accuracy" as expressed by "coefficient of variation" and "bias", respectively. The participation in these programmes was 90%. During the period between 1968 and 1987, inter-laboratory variation decreased markedly where all analyses were concerned. To ensure the necessary and adequate quality, establishment of specifications of quality based on clinical/biological goals of quality has proved necessary. The commonest reasons for large imprecision and bias from the target values are less specific methods of analysis, errors in calibration and sporadic "outliers". As the result of a stable organisation for ensuring quality, Denmark is well equipped for the introduction of the great demands in documentation of quality which may be anticipated from the Common Market during the immediate future.

Chemistry Techniques, Analytical↗
PubMed1988

Danish very-low-dose aspirin after carotid endarterectomy trial.

The effect of very-low-dose aspirin as an antithrombotic agent was evaluated blindly in 301 patients who had recently undergone carotid endarterectomy. After randomization, 150 patients received aspirin and 151 received placebo. The two groups were comparable with regard to age, sex, blood pressure, previous cerebrovascular events, and smoking habits. The effect of the study medication on platelet aggregation was measured twice in each patient during the first 2 months and at each follow-up visit; the dose was individually adjusted. In 76% of the patients receiving aspirin, 50 mg/day gave satisfactory platelet inhibition, 13% needed 60 mg/day, 8% needed 70 mg/day, and 3% needed 100 mg/day. Platelet aggregation was found to be inhibited in only 1.2% of the measurements in the patients receiving placebo. Observation during treatment averaged 21 months; total intention-to-treat follow-up averaged 25 months. For the combined outcome events of transient ischemic attack, stroke, acute myocardial infarction, and vascular death, aspirin reduced risk by 11% (95% confidence limits: -38% to 48%, p greater than 0.1). Thus, there was no significant effect of very-low-dose aspirin in our trial.

Aspirin↗
PubMed1986

Ritodrine in the treatment of preterm labor: second Danish Multicenter Study.

In a randomized trial intramuscular ritodrine followed by oral ritodrine treatment and bed rest was compared with placebo and bed rest in the treatment of 99 cases of preterm labor. The ritodrine treatment did not have a statistically significant effect on birth weight, gestational age, or the incidence of low birth weight. However, it did inhibit preterm labor in the initial stage, resulting in a gain of a few days to a few weeks in length of gestation. This gain may be valuable. Where necessary, advantage can be taken of it to transfer the mother before delivery to a more specialized hospital with a neonatal intensive care unit or to administer steroid treatment to promote fetal lung maturation. No serious side effects were recorded. The intramuscular route is recommended because large fluid infusions are avoided and treatment can easily be started before the patient is transported from home to hospital.

Clinical Trials as Topic↗
PubMed1979

The rabbit cornea lacks cholinergic receptors.

Cholinergic receptors were studied in membranes prepared from rabbit cornea, iris-ciliary body, and retina, using 3H-quinuclidinyl benzilate (3H-QNB) to identify muscarinic receptors and 125I-alpha-bungarotoxin (125I-BGT) to identify nicotinic receptors. Muscarinic cholinergic receptors were not found in the cornea. As a positive control, muscarinic cholinergic receptors were characterized in preparations of the iris-ciliary body. Specific binding of 3H-QNB to iris-ciliary body membrane preparations was saturable, with a Kd of 1.3 nM QNB. Specificity of the assay for muscarinic receptors was confirmed by the relative abilities of the following compounds to displace 3H-QNB: atropine greater than pilocarpine greater than hexamethonium. Nicotinic cholinergic receptors were not found in the cornea. As a positive control, nicotinic cholinergic receptors were characterized in preparations of the retina. Specific binding of 1252-BGT to retinal membrane preparations was saturable with both high and low affinity receptors (Kd values of 1.0 nM and 93 nM BGT, respectively). Specificity of the assay for nicotinic receptors was confirmed by the relative abilities of the following compounds to prevent 125I-BGT binding: curare greater than or equal to nicotine greater than hexamethonium greater than atropine. The lack of cholinergic receptors in the cornea, which has high levels of acetylcholine and related enzymes, suggests either an extraordinary use or a lack of function for acetylcholine in this tissue.

Animals↗
PubMed1977

Spontaneous slow potentials and spreading depression in amphibian retina.

1. In frog and mudpuppy eye cups perfused with low-chloride solution, two types of slow potential phenomena were studied. One type, "spontaneous slow potentials" (SSPs), appeared both in the dark and during light stimuli. The other type, the slow potential change (SPC) of spreading depression (SD), appeared at termination of long-duration light stimuli. 2. The SSPs were analyzed by depth-profile studies, pharmacologic studies, and the use of potassium-specific electrodes. Results indicated that SSPs may represent spontaneous d-waves that travel across the retina. The SSPs are associated with potassium activity, and the main response is probably generated by Müller cells. Initiation and/or propagation appear to require chemically mediated synaptic transmission and impulse activity. 3. Depth-profile studies were also done of the SPC of SD induced by termination of long-duration light stimuli. Results indicated that the SPC is not an exaggerated d-wave. The SPC consists of two components, the second of which reverses more superficially than the d-wave. The main SPC response is probably generated by Müller cells. Although impulse activity does not appear to be necessary for SD, it may contribute to this complex response.

Action Potentials↗
PubMed1976

Bacteriology and antibiotics in acute suppurative otitis media.

One hundred and forty-seven patients with acute suppurative otitis media, were divided into three groups and treated with antibiotics (azidocillin, ampicillin, and cephalexin). The therapeutic effect was assessed bacterioloically by swabbing from the aural discharge and from the nasopharynx on the first, second, third, and seventh day after initiation of treatment. In addition, the concentration of antibiotic in the aural discharge and in the nasopharynx was determined. As compared with other published materials, there was a common occurrence of Haemophilus influenzae and S. Aureus. Hemolytic streptococci are less common than prior to the advent of antibiotics. Pneumococci disappeared in all cases from the aural discharge in the course of the first three days. The effect upon Haemophilus was slower. In the nasopharynx the effect was questionable, and no effect was obtained upon other bacteria. The clinical course could not be correlated to the bacterial findings except that resistant bacteria were found in all cases with persisting discharge.

Ampicillin↗
PubMedDate not supplied

Prolongation of bleeding time and inhibition of platelet aggregation by low-dose acetylsalicylic acid in patients with cerebrovascular disease.

Platelet aggregation and bleeding time was measured in 43 cerebrovascular patients participating in a controlled double-blind study of low-dose acetylsalicylic acid. In 19 patients with satisfactory inhibition of the platelet aggregation obtained by 50 to 70 mg acetylsalicylic acid per day the bleeding time averaged 11.2 minutes in contrast to 7.0 minutes in the placebo group, p less than 0.001. This study confirms our previous findings of platelet inhibition by low-dose acetylsalicylic acid in patients with cerebrovascular disease. The prolongation of the bleeding time demonstrates that we are dealing not merely with an in vitro phenomenon but with a significant in vivo effect. The study provides the rationale for clinical evaluations of low-dose acetylsalicylic acid in stroke prophylaxis.

Aged↗