Biomedical subjects

B Laursen

Publications and source records attributed to B Laursen.

At least 19 recordsLinked to original sources

PubMed2006

Injury patterns in children with frequent emergency department visits.

OBJECTIVES: To compare injury patterns in children with many and few emergency department (ED) visits in order to reveal the causes for the frequent visits. METHODS: Three cohorts of Danish children (total 579 721 children) were followed for three years when their ages were 0-2, 6-8, and 12-14 years. Information on all ED visits was obtained from the Danish National Patient Registry. Injury type, place of accident, injury mechanism, admission, and distance to ED were compared between children with frequent ED visits (five or more during the three years) and children with only one visit. RESULTS: Children with frequent visits had a different injury pattern with 0-46% more superficial injuries and 25-82% more dislocations, sprains, and strains. There was 20-30% fewer fractures and 12% fewer falls from a higher level. 15-51% fewer were admitted. CONCLUSIONS: Children with many ED visits had less severe injuries and more dislocations, sprains, and strains.

Adolescent↗

PubMed2004

Physical workload during use of speech recognition and traditional computer input devices.

Musculoskeletal symptoms among computer users are frequently found. The aim was to investigate the musculoskeletal workload during computer work using speech recognition and traditional computer input devices (keyboard/mouse). Ten experienced computer users (nine female, one male) participated. They performed three different computer tasks: (1). text entry and (2). text editing of a standard text and (3). a self-selected work task. These tasks were performed twice using speech recognition and traditional computer input devices (keyboard/mouse). Additionally, a task consisting of reading aloud of the standard text was performed. Surface EMG from the forearm (m. extensor carpi ulnaris, m. extensor carpi radialis), the shoulder (m. trapezius) and the neck extensor muscles was recorded, in addition to the voice-related muscles (m. scalenii, m. cricothyroideus). Using speech recognition during text entry and text editing reduced the static muscle activity of the forearm, neck and to some extent the shoulder muscles. Furthermore, tendencies to longer periods of muscle activity pause (relative time with EMG gaps) in the forearm and shoulder muscles were found. This was seen at the expense of a tendency to an increased static activity and a decreased relative time with EMG gaps in m. cricothyroideus. Finally, during use of speech recognition the hand was tied to the keyboard/mouse for a shorter period of time, while the eyes were viewing the screen for a longer period of time compared to the condition with traditional computer input devices. It is recommended to use speech recognition as a supplementary tool to traditional computer input devices.

Computer Peripherals↗

PubMed2004

Late puerperal thrombohemorrhagic complications in a patient with antiphospholipid syndrome.

In this study, we present a case of late-puerperal onset of thrombohemorrhagic complications in a 33-yr-old woman with known antiphospholipid syndrome (APS) and heterozygosity for factor V Leiden gene mutation. Antithrombotic prophylaxis with low-molecular-weight (LMW) heparin was given since the 12th gestational week. Pregnancy and cesarean delivery were uncomplicated. Five weeks postpartum, the patient developed a severe hemorrhagic diathesis with marked thrombocytopenia accompanied by vaginal, nasal and cutaneous bleeding. A variety of autoimmune phenomena were also detected, partly at clinical presentation and partly later on, despite ongoing steroid treatment. Platelet counts recovered to normal values within a few weeks secondary to high-dose steroids and intravenous immunoglobulin administration. An ultrasound of both legs, performed because of persistent complaint of moderate calf pain, revealed bilateral deep venous thromboses (DVT). The clinical and biochemical findings were not consistent with thrombotic thrombocytopenic purpura (TTP), heparin-induced thrombocytopenia (HIT) or the 'hemolysis, elevated liver enzymes and low platelet syndrome' (HELLP). The diagnostic criteria for systemic lupus erythematosus (SLE) were not fulfilled either. The complex of thrombohemorrhagic complications and autoimmune phenomena seen in this case is unusual and not previously described in the late puerperal stage of APS-related pregnancies.

Abortion, Habitual↗

PubMed2004

Physical violence, self rated health, and morbidity: is gender significant for victimisation?

STUDY OBJECTIVE: To analyse gender differences in associations between physical violence and self rated health and self reported morbidity among a random sample of adults in Denmark. DESIGN AND SETTING: Two questions on self rated health and self reported morbidity respectively, were obtained from a cross sectional national health interview survey conducted among 12 028 adults (16 years +) in Denmark in 2000. A question on six different forms of physical violence was obtained from a supplementary self administered questionnaire given to the same sample. The reporting period for experienced physical violence was the past 12 months and for morbidity symptoms, the past 14 days. MAIN RESULTS: Men aged 16-24 years were significantly more likely to have experienced violence than women (OR = 3.2, 95% CI = 2.3 to 4.2). Female victims of physical violence were significantly more likely to rate their health as poor (OR = 2.02, 95% CI = 1.41 to 2.89) and to report anxiety (OR = 2.14, 95% CI = 1.35 to 3.37), depression (OR = 2.36, 95% CI = 1.55 to 3.60), and stomach ache (OR = 1.58, 95% CI = 1.01 to 2.47) than female non-victims. Male victims of physical violence were only significantly more likely to report stomach ache (OR = 1.73, 95% CI = 1.03 to 2.89) than male non-victims. CONCLUSIONS: Associations between physical violence and poor self rated health and self reported morbidity were found to be significant for women, but not for men. It is probable that gender differences in experiences of violence, as well as gender differences in health related self perception, contribute to a gender specific process of victimisation. Improved knowledge about the relation between gender specific violence and victimisation as a gender specific consequence is essential for targeting violence prevention.

Adolescent↗

PubMed2003

Biomechanical model predicting electromyographic activity in three shoulder muscles from 3D kinematics and external forces during cleaning work.

BACKGROUND: The shoulder region is a common site of work-related musculoskeletal disorders. Biomechanical models may reveal the relative importance of force, joint-moments, and angular velocity for predicting muscle activity, thereby contributing to identify risk factors. OBJECTIVE: The aim of the present study was to predict muscle activity patterns from joint kinetics during cleaning work and to identify the most important variables requesting muscle activity.Design. A comparative study of six cleaners performing five different floor cleaning tasks (combinations of tool and working method) in a laboratory setting. METHODS: Net forces and moments at the glenohumeral joint were estimated using a video-based 3D link segment model together with 3D force-transducers at each hand, separately. Angular velocities of the upper arm were calculated, and electromyographic activity was recorded bilaterally from the muscles trapezius, deltoideus, and infraspinatus. RESULTS: The biomechanical model revealed abduction moment in the glenohumeral joint to be the most important factor for development of muscle activity in m. deltoideus and m. infraspinatus, while for m. trapezius vertical force was most important. CONCLUSION: Muscle specific determinants for shoulder muscle activity could be identified from glenohumeral joint kinetics. RELEVANCE: This study documents that mechanical work requirements in terms of joint forces, moments of force and angular velocities can predict major fractions of muscle activity patterns in the upper extremities. The biomechanical model used for this prediction revealed different factors of importance for individual muscles. This knowledge is fundamental for work place interventions aiming at minimizing overloading of specific muscles to prevent or rehabilitate muscle disorders.

Activities of Daily Living↗

PubMed2002

Validity of D-dimer tests in the diagnosis of deep vein thrombosis: a prospective comparative study of three quantitative assays.

OBJECTIVES: To assess the diagnostic reliability of a new quantitative D-dimer assay (VIDAS New) and an established quick test (Nycocard D-dimer assay) in the diagnosis of deep vein thrombosis (DVT) compared with ultrasonography. A third assay (Auto Dimer) became available during sample collection and has been included in the final assessment. The diagnostic performance of the Auto Dimer assay was evaluated on three different coagulation analysers. DESIGN: A clinical prospective study of patients admitted to hospital for evaluation of DVT. Setting. The admission ward at Aalborg Hospital. Subjects. A total of 113 outpatients with suspected DVT. Main outcome measures. Compression ultrasonography was used as the reference method for a diagnosis of DVT and compared with different D-dimer assays. The results were expressed as sensitivity, specificity, positive predictive value and negative predictive value (NPV). RESULTS: Deep vein thrombosis was established in 49 patients (43%). Two D-dimer assays (VIDAS New and Auto Dimer) showed sensitivities of 90 and 88%, specificities of 42 and 44%, and NPV's of 85 and 83%, respectively. The Nycocard D-dimer assay showed a sensitivity of 63%, specificity of 67% and NPV of 71%. CONCLUSIONS: The diagnostic performance of VIDAS New and the Auto Dimer D-dimer assays is almost identical, but this study suggests that neither of the D-dimer assays is suitable as the only screening method for DVT, in a situation with a high pretest probability of DVT. This call for a differential strategy that distinguishes between cases of low and high clinical probability using either a D-dimer test or ultrasonography. Abbreviations DVT, deep venous thrombosis, NPV, negative predictive value, PPV, positive predictive value

Adult↗

PubMed2001

Characteristics of closeness in adolescent romantic relationships.

This investigation was designed to describe characteristics of closeness in the romantic relationships of early, mid and late adolescents, and to determine whether adolescent reports of relationship authority and reciprocity are linked to perceptions of interdependence, interaction frequency, activity diversity, influence, and relationship duration. Age was positively associated with interdependence, daily social interaction, weekly activity diversity, and reciprocity but not with influence, authority, or relationship duration; gender was unrelated to all characteristics of closeness. Authority and reciprocity were each positively associated with relationship influence. Authority moderated associations between reciprocity and several characteristics of closeness such that reciprocity was positively linked to interdependence, daily social interaction, and weekly activity diversity, but only in relationships characterized by low levels of authority. Neither reciprocity nor authority was associated with relationship duration.

Adolescent↗

PubMed2001

Performance and muscle activity during computer mouse tasks in young and elderly adults.

The influence of age on performance and muscle activity was studied during computer mouse tasks designed to induce high demands on motor control. Eight young (mean age 25 years) and nine elderly (mean age 63 years) women participated. When the speed was self-determined, the elderly subjects performed 13%-18% slower than did the young. When speed was predefined, the error rate was higher in the elderly subjects than in the young ones (medium precision 7.8% compared to 2.5%, high precision 16.5% compared to 7.9%, respectively). The highest error rate was found for double-clicking (32.9% compared to 13.5%, respectively). The reduced performance in the elderly subjects was hypothesised to be a combined effect of deteriorated proprioception, increased motor unit size, and changes in the central nervous system. Electrical activity (EMG) was recorded from the forearm, shoulder and neck muscles. Higher levels of EMG activity were found in the elderly compared to the young. A likely explanation is that the impaired motor control necessitated an increased muscle activity. The highest levels of EMG activity and lack of EMG gaps were found for the forearm extensor muscles, especially the extensor digitorum muscle (mean EMG activity 10.4% compared to 8.1% of maximal electrical activity, EMGmax) whereas lower EMG activity levels were found for the shoulder region (e.g. right trapezius muscle mean EMG 2.8% compared to 1.1% EMGmax, respectively). The latter was possibly due to a relieving effect of the forearm support. Differences in muscle activity among the tasks were found, however they were minor for the shoulder and neck muscles. Consideration of the demands on motor control when designing user interfaces is recommended, to the benefit of both the young and the elderly.

Adult↗

PubMed2001

Dynamic loads on the upper extremities during two different floor cleaning methods.

BACKGROUND: Biomechanical models have been used frequently to estimate the load on the low back and the lower extremities during occupational work tasks. The shoulder region has received much less attention although this area is a common site of work-related musculoskeletal disorders. OBJECTIVE: The aim of the present study was to evaluate the mechanical loading of the upper extremities during floor cleaning performed with different techniques. DESIGN: A comparative study of six subjects performing floor cleaning with two different techniques (mopping and scrubbing) in a laboratory setting. METHODS: A "force handle" equipped with two force dynamometers was used for continuous measurement of three-dimensional forces on each hand, separately, during this two handed asymmetrical task. A link segment model of the upper extremities was used to calculate the mechanical loading of the elbows and shoulders. Electromyograms were recorded from six shoulder muscles. RESULTS: Despite differences in movement patterns between mopping and scrubbing, only small differences were found in the moments of force. In accordance similar levels of electromyograms were found. CONCLUSION: In preventive strategies, changing the cleaning tool may not be sufficient to change the load on the shoulder muscles. RELEVANCE: Combined three-dimensional video recording and force measurements on the hands during a two-handed asymmetric work tasks allow calculation of the mechanical load on the elbow and shoulder. Thus it is possible to evaluate physiologically, new equipment designed to prevent work-related musculoskeletal disorders. Before introducing such equipment in large scale interventions it may be evaluated if the changes in force requirements are sufficient to predict prevention of musculoskeletal disorders.

Adult↗

PubMed2000

Synthesis of the benzophenone fragment of balanol via an intramolecular cyclization event.

Studies are reported on the use of either a 7-exo radical cyclization or an intramolecular Heck reaction as the key step for the construction of the benzophenone fragment of the PKC inhibitor, balanol. Whereas, the former approach was unsuccessful, the Heck reaction proved to be viable for the coupling of two fully functionalized aryl subunits affording regioselectively a biaryl seven-membered lactone with an exocyclic alkene as the major component, in contrast to the competing eight-membered ring lactone. Hydrolysis of the lactone followed by oxidative cleavage of the alkene with ruthenium tetraoxide completed this short synthesis of the benzophenone unit.

Azepines↗

PubMed2000

Kinetics and energetics during uphill and downhill carrying of different weights.

During physically heavy work tasks the musculoskeletal tissues are exposed to both mechanical and metabolic loading. The aim of the present study was to test a biomechanical model for prediction of whole-body energy turnover from kinematic and anthropometric data during load carrying. Total loads of 0, 10 and 20 kg were carried symmetrically or asymmetrically in the hands, while walking on a treadmill (4.5 km h(-1)) horizontally, uphill, or downhill the slopes being 8%. Mean values for the directly measured oxygen uptake ranged for all trials from 0.5 to 2.1 l O2 min(-1), and analysis of variance showed significant differences regarding slope, load carried, and symmetry. The calculated values of oxygen uptake based on the biomechanical model correlated significantly with the directly measured values, fitting to the line Y = 0.990 X + 0.144, where Y is the estimated and X is the measured oxygen uptake in l min(-1). The close relationship between energy turnover rate measured directly and estimated based on a biomechanical model justifies the assessment of the metabolic load from kinematic data.

Adult↗

PubMed2000

Aspects of shoulder function in relation to exposure demands and fatigue - a mini review.

OBJECTIVE: To discuss the literature on control and function of multiple muscle systems with special focus on shoulder and upper extremity under submaximal conditions. DESIGN: The paper is a mini review based on 31 studies. BACKGROUND: Control mechanisms underlying the recruitment and gradation of muscle activity in complex multiple muscle systems during various voluntary exertions is still not fully understood. Load sharing principles may be influenced by several factors like work demand, fatigability, metabolic factors etc. METHODS: Several methods, e.g., electromyography, intramuscular pressure, and tissue oxygenation are used. The definition of fatigue is discussed. RESULTS AND CONCLUSION: A relatively fixed load sharing of the shoulder muscles has been found at low load levels, submaximal speeds and with a limited range of movements of the arms for healthy subjects. However, the load sharing of the shoulder muscles can be changed to some extent in response to fatigue, mental demands, visual feedback and in patients suffering from disorders in the upper extremities. It is hypothesized that lack of ability to redistribute muscle activation pattern in the shoulder region or the upper extremity increases the risk of development of work related symptoms.

Biomechanical Phenomena↗

PubMed2000

Shoulder muscle activity in young and older people during a computer mouse task.

OBJECTIVE: Assessment of the age effect in relation to computer work. BACKGROUND: Increasingly, more older people are using computers, while hardware and software are not designed with special consideration of their needs. METHODS: Eight young and nine older females performed different computer mouse tasks. Shoulder muscle activity was recorded from the right deltoid muscle, right and left upper trapezius muscle, and the neck extensor muscles. RESULTS: Mean trapezius muscle activity was significantly higher in the older people (2.8%/3.7% EMG(max) for R/L) compared to the young (1.1%/1.2% EMG(max)). There was a tendency to a higher activity in the older people for the deltoid muscle and the neck extensor muscles. There were small differences in shoulder muscle activation levels between mouse actions, target directions, and between precision demands. CONCLUSIONS: Shoulder muscle activity during computer work is affected by age, but only to a minor extent by the type of computer mouse task. The deltoid and the trapezius muscle activities are low during computer mouse use when there is efficient forearm support by the table. RelevanceAn increasing number of people use computers for hours every day. Intensive use of computers increases the risk of development of work-related musculoskeletal symptoms in the shoulder region.

Adult↗

PubMed1998

[Hereditary antithrombin deficiency and pregnancy. Pregnancy course in six women with known hereditary antithrombin deficiency].

Inherited antithrombin (AT) deficiency is a major cause of venous thromboembolism, especially in relation to surgery and pregnancy. We present six AT deficient pregnant women, who successfully delivered seven babies at the Department of Gynaecology/Obstetrics, Aalborg Hospital. From conception, or if possible prior to conception, the women were treated with unfractionated (UFH) or low molecular weight heparin (LMWH) throughout the pregnancy. If the pregnancy was without complication, AT substitution was only used at delivery and for approximately a week post-partum, when warfarin treatment was re-instituted.

Antithrombin III Deficiency↗

PubMed1998

Efficacy of biofeedback in the treatment of urinary stress incontinence.

Thirty-seven women with stress incontinence were given biofeedback instruction on how to perform pelvic floor exercises correctly. After 3 months with home exercises 31 patients performed a new standardized pad-weighing test: 39% were objectively cured and 42% improved. After a mean of 2 years 15 patients were evaluated with another pad-weighing test: 27% were now objectively cured and 47% improved. A questionnaire showed that 78% had an exact knowledge about the location of the pelvic floor muscles and 47% were satisfied with their present situation, but only 58% performed daily exercises.

Adult↗

PubMed1998

Effect of speed and precision demands on human shoulder muscle electromyography during a repetitive task.

Effects of speed and precision on electromyography (EMG) in human shoulder muscles were studied during a hand movement task where five points were marked repeatedly with a pencil. Six female subjects performed with three precision demands and at four speeds. Three of the speeds were predefined, while the last speed was performed as fast as possible. The EMG were recorded from 13 shoulder muscles or parts of muscles. Elbow velocity, acceleration and rectified EMG were calculated for each task. The mean elbow velocity and acceleration increased with speed and precision demands. There was an increase in EMG as the speed demand increased for all three precision demands (P < 0.001), and as the precision demand increased for the two highest predefined speed demands (P < 0.05). The combination of a high speed and a high precision demand resulted in the highest EMG. Different EMG levels were attained for the 13 muscles and the supraspinatus muscle always showed the highest normalized EMG. However, analysis of variance showed the same relative increase for all muscles with speed and precision demands. The EMG changes in response to precision demand can only be explained in part by the differences in movement velocity and acceleration, and other factors such as increased co-contraction must also be taken into account.

Aged↗

PubMed1998

A model predicting individual shoulder muscle forces based on relationship between electromyographic and 3D external forces in static position.

To study the potentiality for developing an EMG-based model for the human shoulder, mapping of relations between static hand forces and electromyographic (EMG) activity of 13 shoulder muscles, were performed. The procedure was to perform by the hands slowly varying isometric forces up to 20% maximum voluntary force in the three-dimensional space. By combining these data with literature values on muscle physiological cross-sectional area and moment arm data, an EMG-based model was developed for estimating muscle forces in the glenohumeral joint. The model was validated for one standardized position by comparing joint moment, calculated from EMG by using the model, with moments from the external force. The highest correlation between these moments was found assuming a linear EMG/force calibration at low force level (< 20% MVC), giving correlations from 0.65 to 0.95 for the abduction/adduction moment and from 0.70 to 0.93 for the flexion/extension moment, for the six subjects. Moments calculated from EMG were for most subjects somewhat lower than the moments from the external force; the mean residual error ranged from 1.6 to 9.9 Nm. Taking this into account, the results can be used for assessment of muscle forces based on recordings of external forces at the hands during submaximal static work tasks without substantially elevated arms.

Adult↗

PubMed1998

Three novel PROC gene lesions causing protein C deficiency.

Missense mutations, three of them novel (Asn210-->Val, Asn248-->Ile, Ala355-->Val), were found in the protein C (PROC) genes of 7 patients with inherited protein C deficiency associated with venous thrombosis. Comparison with the phenotypic effects of mutations in the analogous residues of factor IX causing haemophilia B and the use of molecular modelling has provided explanations as to how these lesions might alter either the structure, function or secretion of the protein C molecules encoded.

DNA Mutational Analysis↗