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Biomedical subjects

P M Nielsen

Publications and source records attributed to P M Nielsen.

At least 19 recordsLinked to original sources
PubMed2001

[Joint charts in drug handling. Toward increased drug safety].

INTRODUCTION: Medication errors contribute to 8% of all hospital admissions. Minimalization of the number of information transferrals and improvement in communication may increase the quality of drug treatment. MATERIAL AND METHODS: The effect of introducing joint charts for prescription and administration on the quality of drug handling in a hospital setting is reported. RESULTS: When separate charts were used the prescriptions in the case records and the nurses' charts for administration did not tally for any of 20 patients. One year after introducing the joint charts, prescriptions for the regular medication and medication on demand were correct and signed for 88% and 48%, respectively, on a patient basis. Ninety-five per cent of the regular administrations were correct and signed. Potential interactions were identified in 15% of the prescriptions. Discharge medication was stated in 65% of the discharge letters to the family doctors. Complete agreement on admission medication between the patient and family doctor was found in 39%. DISCUSSION: Joint charts for prescription and administration represent a significant step towards safe and rational medical treatment. It is more time-consuming. Improvement in communication between all parties involved in the treatment of the same patient represents an important potential for further improving the quality of care, including drug treatment.

Communication↗
PubMed1999

[Randomized controlled trial of high-dose peroral methylprednisolone in attacks of multiple sclerosis].

The efficacy of glucocorticoid treatment in multiple sclerosis (MS) is uncertain. We assessed the effect of oral high-dose methylprednisolone in attacks of MS. Twenty-five patients with an attack of MS with a duration of less than four weeks were randomized to placebo, 26 patients received oral methylprednisolone (500 mg once daily for five days with a 10 days tapering period). Scripps Neurological rating scale scores differed significantly in methylprednisolone and placebo-treated patients the first three weeks (p = 0.005) and after eight weeks (p = 0.0007). Subjective symptom assessment on a visual analogue scale the first three weeks (p = 0.02) and the answers to an efficacy questionnaire administered after eight weeks (p = 0.05) also favoured a beneficial effect of methylprednisolone treatment. The risk of a new attack of MS was not influenced by the treatment at short-term follow up. No serious adverse events were seen. Oral high-dose methylprednisolone is recommended for treatment of attacks of MS.

Adult↗
PubMed1998

Cerebrospinal fluid measures of disease activity in patients with multiple sclerosis.

The potential of magnetic resonance imaging to serve as a surrogate marker of disease activity in patients with multiple sclerosis (MS) is increasingly recognised. In contrast, the use of cerebrospinal fluid analysis has received less attention. We analysed the correlation between clinical data and cerebrospinal fluid parameters in 75 patients with acute optic neuritis (ON) as a possible first symptom of MS, as a symptom of clinically definite MS, and in patients with an attack of MS other than ON. The samples were obtained within 30 days from the onset of an exacerbation. The concentration of myelin basic protein (MBP) in cerebrospinal fluid was significantly correlated with the visual acuity in patients with ON and the Kurtzke EDSS score in patients with MS. The concentration of MBP in CSF also correlated positively with the CSF leukocyte count, intrathecal IgG synthesis, and the CSF-serum albumin concentration quotient. The concentration of MBP in CSF correlated negatively with intrathecal IgA synthesis. The results support the use of the concentration of MBP in CSF as a surrogate marker of disease activity during acute exacerbations of MS; the data also link the presence of MBP in CSF to neuroimmunological parameters.

Adolescent↗
PubMed1998

Double-blind, randomized, placebo-controlled study of oral, high-dose methylprednisolone in attacks of MS.

OBJECTIVE: There is only limited evidence from adequately controlled clinical trials to support high-dose methylprednisolone therapy for attacks of multiple sclerosis (MS) and none supporting oral administration. We assessed the effect of oral high-dose methylprednisolone therapy in attacks of MS. METHODS: Twenty-five patients with an attack of MS lasting less than 4 weeks were randomized to placebo treatment. Twenty-six patients received oral methylprednisolone (500 mg once a day for 5 days with a 10-day tapering period). The patients received scores on the Scripps Neurological Rating Scale (NRS) and Kurtzke Expanded Disability Status Scale. The symptoms were scored on a visual analog scale (VAS) before treatment and after 1, 3, and 8 weeks of treatment. Primary efficacy measures were NRS and VAS scores in the first 3 weeks and changes in NRS score and answers to an efficacy questionnaire administered after 8 weeks of treatment. RESULTS: Changes in NRS scores among methylprednisolone- and placebo-treated patients differed significantly in the first 3 weeks and after 8 weeks (p = 0.005 and p = 0.0007). VAS scores the first 3 weeks and treatment efficacy after 8 weeks also favored a beneficial effect of methylprednisolone treatment (p = 0.02 and p = 0.05). After 1, 3, and 8 weeks, 4%, 24%, and 32% in the placebo group and 31%, 54%, and 65% in the methylprednisolone group had improved one point on the Expanded Disability Status Scale score (all p < 0.05). No serious adverse events were seen. CONCLUSION: Oral high-dose methylprednisolone is recommended for managing attacks of MS.

Administration, Oral↗
PubMed1992

An anatomical heart model with applications to myocardial activation and ventricular mechanics.

A three-dimensional finite element model of the mechanical and electrical behavior of the heart is being developed in a collaboration among Auckland University, New Zealand; the University of California at San Diego, U.S.; and McGill University, Canada. The equations of continuum mechanics from the theory of finite deformation elasticity are formulated in a prolate spheroidal coordinate system and solved using a combination of Galerkin and collocation techniques. The finite element basis functions used for the dependent and independent variables range from linear Lagrange to cubic Hermite, depending on the degree of spatial variation and continuity required for each variable. Orthotropic constitutive equations derived from biaxial testing of myocardial sheets are defined with respect to the microstructural axes of the tissue at the Gaussian quadrature points of the model. In particular, we define the muscle fiber orientation and the newly identified myocardial sheet axis orientation throughout the myocardium using finite element fields with nodal parameters fitted by least-squares to comprehensive measurements of these variables. Electrical activation of the model is achieved by solving the FitzHugh-Nagumo equations with collocation at fixed material points of the anatomical finite element model. Electrical propagation relies on an orthotropic conductivity tensor defined with respect to the local material axes. The mechanical constitutive laws for the Galerkin continuum mechanics model are (1) an orthotropic "pole-zero" law for the passive mechanical properties of myocardium and (2) a Wiener cascade model of the active mechanical properties of the muscle fibers. This chapter concentrates on two aspects of the model: first, grid generation, including both the generation of nodal coordinates for the finite element mesh and the generation of orthotropic material axes at each computational point, and, second, the formulation of constitutive laws suitable for numerically intensive finite element computations. Extensions to this model and applications to the mechanical and electrical function of the heart are described in Chapter 16 by McCulloch and co-workers.

Animals↗
PubMed1991

Diagnosis of alveolar bone changes with digital subtraction images and conventional radiographs. An in vitro study.

The purpose of the present study was to compare the diagnostic properties of radiographs obtained with Ultra-Speed and Ektaspeed films when analyzed conventionally radiographs and after conversion in digital subtraction images. Artificial lesions, measuring 0.5, 0.7, 0.9, and 1.1 mm in diameter, were drilled in a dry skull with slow-speed burs. Standardized radiographs were obtained by means of acrylic bite blocks and a modification of the Rinn system. The results of this study demonstrated that sensitivity in the detection of the lesions was doubled after digitizing and displaying subtraction images compared with the conventional radiographic interpretation, independent of the use of Ektaspeed or Ultra-Speed films for the original radiographs. The diagnostic information seemed to be equal in radiographs obtained from Ultra-Speed and Ektaspeed films after digitization and image processing procedures.

Alveolar Bone Loss↗
PubMed1991

Biaxial testing of membrane biomaterials: testing equipment and procedures.

A testing facility for measuring the biaxial mechanical properties of highly deformable membranes is described. Forces are applied, via strain-gauge force transducers, to four points on each side of an initially square 12 to 25 mm membrane sample to produce biaxial extensions of up to 80 percent of undeformed length. Strain is estimated from the displacement of markers bounding a 1 to 2 mm central square. The accuracy of stress and strain field measurements has been assessed by finite element analysis of a biaxially-loaded isotropic elastic membrane. Major advantages of the present system over those previously described in the literature are that 1) sample mounting procedures are simplified, 2) there is provision for independent adjustment of stress field uniformity and measurement of the applied point forces and 3) faster strain rates can be imposed on the relatively small samples tested.

Animals↗
PubMed1991

Mathematical model of geometry and fibrous structure of the heart.

We developed a mathematical representation of ventricular geometry and muscle fiber organization using three-dimensional finite elements referred to a prolate spheroid coordinate system. Within elements, fields are approximated using basis functions with associated parameters defined at the element nodes. Four parameters per node are used to describe ventricular geometry. The radial coordinate is interpolated using cubic Hermite basis functions that preserve slope continuity, while the angular coordinates are interpolated linearly. Two further nodal parameters describe the orientation of myocardial fibers. The orientation of fibers within coordinate planes bounded by epicardial and endocardial surfaces is interpolated linearly, with transmural variation given by cubic Hermite basis functions. Left and right ventricular geometry and myocardial fiber orientations were characterized for a canine heart arrested in diastole and fixed at zero transmural pressure. The geometry was represented by a 24-element ensemble with 41 nodes. Nodal parameters fitted using least squares provided a realistic description of ventricular epicardial [root mean square (RMS) error less than 0.9 mm] and endocardial (RMS error less than 2.6 mm) surfaces. Measured fiber fields were also fitted (RMS error less than 17 degrees) with a 60-element, 99-node mesh obtained by subdividing the 24-element mesh. These methods provide a compact and accurate anatomic description of the ventricles suitable for use in finite element stress analysis, simulation of cardiac electrical activation, and other cardiac field modeling problems.

Animals↗
PubMed1989

[Periodontal disease and its treatment].

A well known development of the chronic periodontal disease is reviewed. However, the histological picture of a gingiva varies at a much lower speed than its clinical picture, and slower than previously described. In presence of periodontitis there may exit a zone of reversible disease of about 2 mm, which give the possibility of obtaining a re-attachment of unknown magnitude. A new connective tissue attachment (on top of the re-attachment) seems only possible if the periodontal ligament cells are allowed to proliferate coronally.

Dental Plaque↗
PubMed1989

Effects of technical parameters on image perception using two types of dental radiographs.

In radiology a sufficient diagnostic accuracy must be obtained with a minimal radiation dosage to which the patients are exposed. In-vitro studies designed to evaluate the influence of technical parameters on the quality of images on Kodak Ektaspeed and Kodak Ultra-Speed dental radiographs are presented. The following series of experiments were performed: 1. Evaluation of the Minray dc, Soredex and Oralix 65, Philips X-ray machines. 2. Comparison between two different Oralix 65 machines. 3. Evaluation of automatic and manual film processing as well as film-focus distances of 30 cm and 39 cm. 4. Evaluation of pairs of radiographs and their subtraction images obtained from different film and X-ray machine combinations. A dried mandible with and without bone splits within the central X-ray beam area on the alveolar crest between the teeth 46 and 47 served as object for the standardized images. A blind comparison of the series of images was performed by 3 certified periodontists. Irrespective of the film type used the highest rankings were given to the Oralix 65 X-ray machine, when the films were exposed at 39 cm from the focus and the automatic processing mode was used. X-ray images with good anatomical and technical details may be obtained on Ektaspeed and Ultra-Speed films. However, preference must be given to Ektaspeed films because of the possibility of reducing the radiation exposure.

Evaluation Studies as Topic↗
PubMed1988

A method to determine methylmethacrylate in air.

To determine the air concentrations of methylmethacrylate monomer and thus obtain information about the safety in the operating theater, a methylmethacrylate Dräger tube was used in connection with a bellows pump. This method gives an instantly readable value correlated with more complicated gas chromatographic measurements.

Air Pollutants, Occupational↗
PubMed1987

Acute cervico-facial actinomycosis.

Cervico-facial actinomycosis still occurs occasionally and should be included in the differential diagnosis of infectious processes in the jaws and the oral cavity. The typical actinomycosis-cases are clinically chronic in nature; however actinomycosis may be atypical with subacute or acute clinical manifestations. Among 37 cases of infectious processes in the jaws treated with extraoral incision between 1980 and 1985 in the Department of Oral Surgery, School of Dental Medicine, University of Berne, 3 (8%) were diagnosed as acute actinomycosis according to the following procedure. Prior to incision, pus was aspired under aseptic conditions. Presence of gram-positive branched filaments in the microscopically examined pus led to the suspicion of actinomycosis. This diagnosis was confirmed by cultivation of Actinomyces israelii using the anaerobic culture method, biochemical characteristics and gas-liquid chromatographic analysis of metabolic products. These 3 actinomycosis-cases were successfully treated by surgical removal of the suspicious foci and by administration of clindamycin per os for 16 days.

Actinomyces↗
PubMed1987

Fractures of the femoral neck treated with a bipolar endoprosthesis.

Seventy-five patients with 77 bipolar hip endoprostheses were reexamined and had roentgenograms taken at an average of 51 months postoperatively. The average age of the patients was 77 years. All prostheses had been inserted due to intracapsular fractures of the femoral neck. Three prostheses had been revised to a total hip arthroplasty at the time of follow-up examination. Radiologically, three cases of protrusion and ten cases with a radiolucent zone greater than 2 mm around the femoral stem were found. Functionally, the result was excellent or good in about 75% of the active ambulators. As acetabular erosion and protrusion appears to have been reduced to some extent, a bipolar hip prosthesis is found to be a good alternative to conventional hemiarthroplasty in elderly patients with a fracture of the femoral neck.

Aged↗