Ola Thorsson

Effects of Therapeutic Ultrasound on the Regeneration of Skeletal Myofibers After Experimental Muscle Injury

Therapeutic ultrasound is used by many in the treatment of muscle injuries, but no previous attempts to objectively assess its effects on regenerating skeletal myofibers have been published. In this descriptive study, we followed the regeneration of contusion injury to the rat gastrocnemius muscle during treatment with pulsed ultrasound. The speed of myoregeneration in ultrasound-treated animals was compared with that in control animals by immunohistochemical, morphometric, and scintigraphic analyses. Although satellite cell proliferation was enhanced significantly (up to 96%) by the ultrasound treatment during the early stages of regeneration, there was no such effect on myotube production. The period of rapid fibroblast proliferation was extended from 3 to 4 days in the control group to 7 to 10 days in the ultrasound therapy groups, whereas recapillarization was virtually unaffected. We conclude that although treatment with pulsed ultrasound can promote the satellite cell proliferation phase of the myoregeneration, it does not seem to have significant effects on the overall morphological manifestations of muscle regeneration.

Daily physical activity in Swedish children aged 8–11 years

Introduction: Physical inactivity is hypothesized to be a contributing factor in the development of a variety of diseases. Recommendations for an adequate level of physical activity have been proposed. There are few studies in which the physical activity in children has been objectively assessed. The purpose of this study was to estimate objectively the level of physical activity in Swedish children.

Daily physical activity related to aerobic fitness and body fat in an urban sample of children.

This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8–11 years. A cross‐sectional study of 225 children aged 7.9–11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual‐energy x‐ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days and daily accumulation of moderate‐to‐vigorous and vigorous activity was calculated. Significant relationships (P<0.05) existed for vigorous activity vs ln BF% (r=−0.40), ln AFM (r=−0.35), TBF/AFM (r=−0.22) and aerobic fitness (r=0.38), whereas moderate‐to‐vigorous activity displayed weaker relationships (−0.22, −0.18, −0.12 NS, and 0.25). Multiple regression analyses with inclusion of possible confounders concluded that vigorous activity was independently related to aerobic fitness and ln BF% or ln AFM. Moderate‐to‐vigorous activity was only independently related to aerobic fitness. In this population, low daily accumulation of vigorous activity was, already in children aged 8–11 years, associated with more body fat and lower aerobic fitness. A similar relation was not found for daily accumulation of moderate‐to‐vigorous activity.

Reference values for respiratory system impedance by using impulse oscillometry in children aged 2-11 years.

The forced oscillation technique makes it possible to evaluate the mechanical properties of the respiratory system with a minimum of cooperation. The method is therefore especially useful in children. Impulse oscillometry (IOS) is a commercially available version of this technique. There is, as yet, limited information on reference values for IOS in children. The aim of this study was to extend the reference values for IOS variables and to study their correlation with height, weight and age in healthy children. A sample (n = 360) of children (age 2·1–11·1 years) was measured by using impulse oscillometry (IOS; Jaeger, Würzburg, Germany). The sample was based on children attending kindergarten in Finland and children attending primary school in Sweden. Measurements of respiratory resistance (Rrs) and reactance (Xrs) at 5, 10, 15 and 20 Hz, total respiratory impedance (Zrs) and the resonance frequency (Fr) were made. All variables were related to body height. Most of them were also weakly related to weight. Reference equations for children (height 90–160 cm) are presented.

Ultrasound examination of soft tissue injury of the lower limb in athletes

We performed ultrasonography on 32 athletes com plaining of intense pain in a swollen and tender thigh or calf after a contusion or stretching trauma. The ultra sonogram was used to visualize the presence and size of a suspected hematoma. The findings included the following: 7 patients with a circumscribed, anechoic lesion compatible with a liquefied hematoma; 10 pa tients with a circumscribed lesion of mixed echogenicity compatible with areas of liquefied hematoma, coagu lated blood, and edema; and 15 patients with a diffuse change in echogenicity of the whole muscle. The cir cumscribed liquefied, and mixed hematoma were more common after contusion trauma, while the diffuse type was more common after injury caused by stretching. Ultrasonography is useful in localizing the hematoma and in characterizing the different types. Differentiation is important in diagnosis and choice of treatment.

Immediate external compression in the management of an acute muscle injury

In a prospective, non‐randomized study 40 athletes with contusion or distension injuries to the thigh or the calf muscle were followed with tests of range of motion (ROM) of knee or ankle joint, test of serum creatine kinase (CK) and ultrasonography of the injury until completely recovered. An experimental group of 19 injuries where subjects received treatment with application of a maximum compression bandage within 5 min (mean=2 min) of the injury was compared to a control group of 21 injuries where subjects were treated with rest and elevation only, and in some cases non‐maximum compression after 10–30 min. No significant differences were noted with respect to time to complete subjective recovery, ultrasonic size of the injury or time to normal findings on ultrasound between treatment and control groups. Strain injuries, although showing a tendency to be smaller in size, took a longer time to complete recovery than contusion injuries (mean±SD=26±22 days and 19±9 days, respectively, P=0.02). Diagnostic CK values and reductions in ROM were not correlated to the severity of the trauma, while ROM showed weak correlation to the sonographically measured size of the hematoma (r=0.42; P<0.01). Injuries displaying a circumscript anechoic, low‐echogenic or mixed lesion at the diagnostic ultrasound investigation normalized more slowly (P=0.001) and took longer to complete recovery (P=0.001) than injuries with diffuse hyperechogenic lesions. We conclude that in this study the application of a maximum compression bandage within 5 min of a muscle trauma did not significantly reduce the size of the hematoma nor significantly shorten the time to complete subjective recovery compared with no immediate treatment. The diagnostic ultrasound investigation was valuable in predicting the severity of the trauma.

A 14-year prospective study of autonomic nerve function in Type 1 diabetic patients: association with nephropathy

Aims  Prospective studies of autonomic nerve function are rare. We have followed the progression of autonomic dysfunction in relation to nephropathy over 14 years in Type 1 diabetic patients.

BMI and objectively measured body fat and body fat distribution in prepubertal children

Background  Body Mass Index (BMI) is often used as a surrogate estimate of body fat in epidemiological studies. This study explores the association between BMI, body fat and body fat distribution assessed by Dual‐Energy X‐Ray Absorptiometry (DXA) in younger children.

Prediction of fat-free body mass from bioelectrical impedance among 9-to 11-year-old Swedish children

Aim:  Predictive equations for estimating body composition from bioelectrical impedance analysis (BIA) among Scandinavian children are lacking. In the present study, equations for estimation of fat‐free body mass (FFM) and lean tissue mass (LTM) were developed and cross‐validated from BIA using dual‐energy X‐ray absorptiometry (DXA) as the reference measurement of body composition.

Oesophageal dysmotility, delayed gastric emptying and gastrointestinal symptoms in patients with diabetes mellitus.

Aims  Gastroparesis is a common gastrointestinal complication in diabetes mellitus, whereas dysfunction in the other gastrointestinal organs has been less thoroughly investigated. Furthermore, it is not known whether there is any relationship between motility and dysmotility between these organs. The aim of this study was to examine whether diabetic patients with gastrointestinal symptoms also have motility disturbances in the oesophagus and stomach and, if so, whether there are any associations between these disturbances.