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Biomedical subjects

E Bäckman

Publications and source records attributed to E Bäckman.

At least 19 recordsLinked to original sources
PubMed1996

Chronic regional muscular pain in women with precise manipulation work. A study of pain characteristics, muscle function, and impact on daily activities.

Pain characteristics, muscle function and impact on daily activities were studied in 39 women with chronic regional muscular pain (RMP). They were all blue-collar workers in work involving precise manipulations. The main location of the pain was in the neck-shoulder region. Nineteen age-matched women with fibromyalgia (FM) were studied in the same way as the RMP patients. Thirty-seven women with no pain and with the same age and weight as the RMP patients served as reference group with respect to muscle strength and endurance. A follow-up study was done with respect to pain distribution and other pain characteristics 20 months after the initial examination. The findings were of the same nature in the RMP and the FM groups. The intensity of pain, the lowering of pain threshold for pressure, and the degree of sleep disturbance were greater in the FM than in the RMP group. Isometric muscle strength and static muscular endurance were reduced in both FM and RMP compared to reference values. The reduction in strength and endurance was greater in FM than in RMP. Even if the impact on everyday activities were greater in FM than in RMP, the impact was substantial in RMP patients also, for example with regard to work capacity. There were no transitions from RMP to FM during the 20 months to follow-up. Three FM patients, however, did not meet the ACR criteria for FM at follow-up.

Activities of Daily Living↗
PubMed1995

Phospholipase A2 activity in dystrophinopathies.

Phospholipase A2 activity in human muscle with or without dystrophin abnormality was studied. The results showed an increased phospholipase A2 activity in Duchenne muscular dystrophy (DMD) patients (1160 +/- 160, P < 0.01) compared to controls (< 200 U mg-1). DMD fetal muscle showed normal levels, but levels then increased dramatically postnatally. Highest levels were found at 5 yr of age (10 times normal) and then declined to 1.5-2 times normal by age 10. Steroid treatment did not change the phospholipase A2 levels significantly. In patients with abnormal dystrophin, i.e. Becker muscular dystrophy, phospholipase A2 activity was increased in the age group 3-15 (920 +/- 230 U mg-1, P < 0.01), while older patients (17-49) showed a non-significant (220 +/- 60 U mg-1) increase. The lack of phospholipase A2 activation in fetuses with DMD, indicates that activation is not a direct consequence of dystrophin deficiency. Phospholipase A2 activity has been shown to be connected to the formation of several inflammatory mediators such as prostaglandins, leukotriens, platelet activating factor and lysophospholipids. Phospholipase A2 activation may therefore play an important role in the development of inflammation and necrosis, with subsequent fibrosis and massive loss of muscle function, which develops in Duchenne and Becker muscular dystrophy.

Adolescent↗
PubMed1995

Low-dose prednisolone treatment in Duchenne and Becker muscular dystrophy.

Forty-one boys, aged 4.0-19.4 yr, with Duchenne or Becker muscular dystrophy, took part in a 12-month randomized, double-blind cross-over trial in which the patients received 0.35 mg kg-1 day-1 prednisolone for six months and placebo for six months. One patient stopped the treatment because of excessive weight gain. The boys were assessed every third month with a comprehensive test battery of muscle force and function. The results support earlier reports that prednisolone treatment can either improve muscle force and function or diminish the deterioration of muscle function in both Becker and Duchenne muscular dystrophy.

Adolescent↗
PubMed1995

Pain analysis in patients with fibromyalgia. Effects of intravenous morphine, lidocaine, and ketamine.

Pain intensity, muscle strength, static muscle endurance, pressure pain threshold, and pain tolerance at tender points and control points were assessed in 31 patients with fibromyalgia (FM), before and after intravenous administration of morphine (9 patients), lidocaine (11 patients), and ketamine (11 patients). The three different studies were double-blind and placebo-controlled. The patients were classified as placebo-responders, responders (decrease in pain intensity by > 50%) and non-responders. The morphine test did not show any significant changes. The lidocaine test showed a pain decrease during and after the infusion. The ketamine test showed a significant reduction in pain intensity during and after the test period. Tenderness at tender points decreased and endurance increased significantly, while muscle strength remained unchanged. The present results support the hypothesis that the NMDA receptors are involved in pain mechanisms in fibromyalgia. These findings also suggest that central sensitization is present in FM and that tender points represent secondary hyperalgesia.

Adult↗
PubMed1995

Isometric muscle strength and muscular endurance in normal persons aged between 17 and 70 years.

Isometric muscle strength was measured in 63 women and 65 men, randomly selected, aged 17-70 years, using Penny & Giles' hand-held dynamometer. Eight muscle groups as well as the hand grip strength were tested bilaterally. The muscular endurance was measured as time to exhaustion in the abductors of the shoulder and the flexors of the hip. Reference values for muscle strength and muscular endurance are given in the age groups 17-18, 20-29, 30-39, 40-49, 50-59 and 60-70 years of age. The mean strength of females was about 65-70% of that of the men, but when the results were related to weight, the differences almost disappeared. Both men and women seem to have the greatest muscle strength at the age of about 17-18. The strength is rather constant up to the age of about 40 years, after which a discrete decline is seen up to about 60, from where the decline is more obvious. Muscular endurance showed great variability between individuals. However, no decrease in endurance was seen in older ages. For both sexes, lower reference limits of endurance, with the methods used, for arm abductors are suggested as being 3 minutes and for hip flexors, 90 seconds.

Adolescent↗
PubMed1995

Muscle function in juvenile chronic arthritis.

OBJECTIVE: Muscle strength and thickness were studied in children with juvenile chronic arthritis (JCA) to evaluate their muscle function. METHODS: We studied voluntary isometric, isokinetic, and nonvoluntary isometric muscle strength, as well as muscle thickness, in 20 children with JCA. Thickness of the quadriceps muscle was measured by ultrasound. Results were compared with reference values for healthy children and a matched control group. RESULTS: Isometric muscle strength in knee extensors, elbow flexors, and wrist dorsiflexors was reduced in children with JCA. In muscles near an inflamed joint, the strength was 45-65% of expected value. In muscles without adjacent arthritis, the strength was slightly decreased (80-90% of expected value). Isometric and isokinetic strength in ankle dorsiflexors was reduced only in children with ankle arthritis. Nonvoluntary muscle strength in thumb adductors during electrical stimulation of the ulnar nerve was reduced in children with arthritis in the hand. Thickness of the quadriceps muscle was reduced both in children with and without knee arthritis (75 and 90% of expected). CONCLUSION: Children with JCA have reduced muscle strength and thickness, which is most pronounced in muscles near an inflamed joint.

Adolescent↗
PubMed1992

The heart in Duchenne muscular dystrophy: a non-invasive longitudinal study.

Sixteen boys with Duchenne muscular dystrophy (DMD) underwent serial investigations of echocardiographic left ventricular dimensions, systolic time intervals (STI), ECG and vectorcardiography (VCG). Spirometry with measurement of vital capacity and forced expiratory volume was also performed, as well as tests of muscle function. ECG was abnormal with high right precordial R-amplitudes even in the youngest patients. In contrast, VCG QRS area progressively diminished with age. STI and echocardiographic contractility indices decreased with increasing age. There was no clinically useful relationship between the various non-invasive variables on the one hand and results from skeletal muscle tests or lung function tests on the other, or between the different cardiac investigation methods. It is concluded that several non-invasive tests are needed during follow-up studies of Duchenne patients to evaluate the effects of treatment or assess prognosis.

Adolescent↗
PubMed1991

Quantification of extrajunctional acetylcholine receptors in human muscle biopsies.

Extrajunctional acetylcholine receptors were quantified in human muscle biopsies by in vitro autoradiography with 3H-alpha-bungarotoxin (alpha-Btx). Specific alpha-Btx binding was found in seven of eight biopsies with histological and/or histochemical signs of denervation. The highest binding (21 fmol/mg) was seen in the biopsy with the most pronounced signs of denervation. The specimens with co-existing signs of innervation had generally lower binding levels. Four of the control biopsies showed low binding (less than or equal to 1 fmol/mg) while no specific binding could be detected in the other six controls. The findings suggest that this method cannot only be used to demonstrate denervation in muscle biopsy specimens, but also to give a quantitative measure of the changes.

Adolescent↗
PubMed1991

Characteristics of tetanic muscle contraction in Parkinson patients.

The aim of this study was to examine contraction characteristics in striated muscles from Parkinson patients and to measure any changes in characteristics based on changes in medication. Fifteen patients, 9 men and 6 women, mean age 61.6 (range 43-70) with mild to moderate parkinsonism, (Hoehn and Yahr I-III) were investigated, and the results were compared with a group of 8 normal controls (mean age 59.6, range 50-70). Twelve of the patients (7 men and 5 women) were also tested after a 24-h period without medication. Using supramaximal electrical stimulation of the ulnary nerve at the wrist contraction, characteristics in the m. adductor pollicis muscle can be recorded. Stimulation results were printed on a fast paper writer. The following characteristics were recorded: 1) electromechanical delay of contraction EMDc; 2) contraction time to half tetanus CTT1/2; 3) electromechanical delay of relaxation EMDr; 4) relaxation rate RR for 10 ms RR-10; 5) the force produced in the tetanic contraction at stimulus frequencies 5, 10, 20, 50 Hz. The results showed that the in initiation of contraction (EMDc) was normal compared with controls. CTT1/2 was shorter (p less than 0.001) in the group of Parkinson patients compared with normals. EMDr was not changed when compared with normals, but RR-10 was increased, p less than 0.05. Force levels at the different stimulation rates were not significantly changed. After withdrawal of medication all parameters were unchanged. Muscle contraction characteristics in tetanic contraction were found to be abnormal indicating either a possible preactivation in the muscle contraction or a secondary change in the muscles of patients with Parkinson's disease.

Adult↗
PubMed1990

Effect of sodium selenite and vitamin E treatment in myotonic dystrophy.

Fifteen patients with myotonic dystrophy, seven men and eight women, of age range 15-55 years, were treated with sodium selenite and vitamin E for 2 years. The patients were examined using a number of tests to assess muscle force and function at the start of the treatment period and 6, 12 and 24 months thereafter. Myotonia gives an increased relaxation time. The latter was measured in the adductor pollicis. There was a significant decrease in half relaxation time before treatment compared with the values during treatment. In summary, the results indicate that selenium and vitamin E therapy may have an effect on myotonia. The effects of treatment on motor functions were minimal, and overall motor performance was not improved.

Adult↗
PubMed1989

Isometric muscle force and anthropometric values in normal children aged between 3.5 and 15 years.

Isometric muscle force was measured in 217 normal children aged 3.5-15 years. The standard error of a single determination made by the same observer was ca. 9% of the muscle force. When two measurements were made by different observers the standard error of the difference was estimated at ca. 17%. Reference values for isometric force are given for boys and girls separately. With regard to 7 of the 10 muscle groups tested the force was significantly greater in boys than in girls as early as at ca. 10 years of age. Age and weight were the most important predictors of muscle force.

Adolescent↗
PubMed1989

Isokinetic muscle torque in the dorsiflexors of the ankle in children 6-15 years of age. Normal values and evaluation of the method.

Isokinetic muscle torque of the dorsiflexors of the ankle was tested in 137 children 6-15 years old. Reference values in different age groups are given for girls and boys separately. Generally, peak torque values increased with age. However, the developed torque/kg bodyweight showed no significant difference in 15-year-old girls compared to 12-year-old girls. For prediction of normal torque the best parameters are age, weight and height. The maximal torque and work values generally increased with increasing weight and height. The prediction was not improved by adding factors like length of the lower leg, calf circumference and length of the foot. In the youngest age groups, the stronger leg, in the highest velocities, was on the dominant side, while in the older groups the strongest leg, at least in slow velocities, was on the non-dominant side. The boys seem to have their most intensive force development between 12 and 15 years while this occurs earlier in girls.

Adolescent↗
PubMed1988

Skeletal muscle characteristics in children 9-15 years old: force, relaxation rate and contraction time.

Relaxation rate (RR), half contraction time to tetanus (CTT1/2) and force-frequency curves were investigated in 77 children, aged 9-15 years, using supramaximal stimulation of the ulnar nerve and recording from the adductor pollicis muscle. No sex differences were found in these variables. The RR was independent of age and similar to that in adults. The CTT1/2 was least at the age of 15. The only age-dependent parameter in the force-frequency curves was the relative force developed at a stimulus frequency of 10 Hz, which increased with increasing age. A fatiguability test was performed in 25 children. Reference values for the different parameters are given.

Adolescent↗
PubMed1988

Selenium and vitamin E treatment of Duchenne muscular dystrophy: no effect on muscle function.

16 boys with Duchenne muscular dystrophy (DMD) were treated with sodium selenite and vitamin E for one year. One group of patients (10 boys) was examined using a battery of tests to assess muscular strength and function and cardiopulmonary function, and by CT scanning of 2 muscle groups over the 4 years prior to treatment. Six boys with DMD entered the study when the treatment was begun. Tests of muscular force and function, cardiopulmonary tests and CT-scanning were performed at the onset of treatment, and after 6 and 12 months. No beneficial effect on either muscular force or function was found during the treatment period. It is concluded that selenium and vitamin E in high doses do not improve muscle function in DMD.

Adolescent↗
PubMed1988

Skeletal muscle function in primary fibromyalgia. Effect of regional sympathetic blockade with guanethidine.

Muscle fatigue is the most disabling symptom in primary fibromyalgia (PF), which in addition is characterized by generalised pain and muscle stiffness. In order to assess whether the fatigue is of central and/or peripheral origin, skeletal muscle function was studied by measuring maximum voluntary hand grip strength, and by measuring various contraction characteristics in the adductor pollicis muscle after electrical stimulation of the ulnar nerve. The PF-patients were also studied after a regional sympathetic blockade of the forearm with guanethidine. A lower hand grip strength was found in the PF-patients compared to the controls, before as well as during the sympathetic blockade. The developed force, measured during electrical stimulation, did not differ between patients and controls. A lower muscle relaxation rate was found in the PF-patients. The relaxation rate increased in the PF-patients during the sympathetic blockade. The results indicate both a central and a peripheral cause of muscle dysfunction. Activity in the muscle sympathetic system may be one link in the chain of events that leads to muscular symptoms in PF.

Action Potentials↗
PubMed1988

Skeletal muscle contraction characteristics in vivo in malignant hyperthermia susceptible subjects.

Ten malignant hyperthermia susceptible (MHS) subjects were investigated, all of them positive in in vitro tests. As a control group 12 healthy subjects were investigated. The investigation was done in a blind fashion during strictly standardized conditions. Electromechanical delay of contraction and half contraction time to tetanus were faster (P less than 0.05) while half relaxation time was shorter in the MHS subjects (P less than 0.05). Skin and intramuscular temperature were significantly higher in the MHS subjects (P less than 0.05). This indicates that MHS subjects differ in various skeletal muscle characteristics during "normal" conditions. Further studies to define the temperature level at which the test of muscle function is most discriminating are needed before it can be used for diagnostic purposes.

Adolescent↗