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Biomedical subjects

T Saartok

Publications and source records attributed to T Saartok.

At least 19 recordsLinked to original sources

Type of acute hamstring strain affects flexibility, strength, and time to return to pre-injury level.

OBJECTIVES: To investigate possible links between aetiology of acute, first time hamstring strains in sprinters and dancers and recovery of flexibility, strength, and function as well as time to return to pre-injury level. [figure: see text]. METHODS: Eighteen elite sprinters and 15 professional dancers with a clinically diagnosed hamstring strain were included. They were clinically examined and tested two, 10, 21, and 42 days after the acute injury. Range of motion in hip flexion and isometric strength in knee flexion were measured. Self estimated and actual time to return to pre-injury level were recorded. Hamstring reinjuries were recorded during a two year follow up period. RESULTS: All the sprinters sustained their injuries during high speed sprinting, whereas all the dancers were injured while performing slow stretching type exercises. The initial loss of flexibility and strength was greater in sprinters than in dancers (p<0.05). At 42 days after injury, both groups could perform more than 90% of the test values of the uninjured leg. However, the actual times to return to pre-injury level of performance were significantly longer (median 16 weeks (range 6-50) for the sprinters and 50 weeks (range 30-76) for the dancers). Three reinjuries were noted, all in sprinters. CONCLUSION: There appears to be a link between the aetiologies of the two types of acute hamstring strain in sprinters and dancers and the time to return to pre-injury level. Initially, sprinters have more severe functional deficits but recover more quickly.

Adolescent↗

Calcitonin gene related peptide and neuropeptide Y in skeletal muscle after eccentric exercise: a microdialysis study.

OBJECTIVES: To detect neuropeptides in human skeletal muscle at rest and after eccentric exercise. METHOD: Eight healthy subjects participated in the study. Microdialysis of the distal part of the vastus lateralis of the quadriceps muscle and pain evaluation were performed immediately after eccentric exercise, after two days, and at rest. Calcitonin gene related peptide (CGRP) and neuropeptide Y (NPY), representatives of the sensory and autonomic nervous system, were analysed by radioimmunoassay. RESULTS: Overall, the measured concentrations were low, some even below the limit of detection. At rest, CGRP was detected in two of seven samples, but after eccentric exercise it was detected in 27 of 30 samples. At rest, all NPY concentrations were below the limit of detection, but after exercise it was found in six of 30 samples. CONCLUSION: The significant increase in detectability of CGRP after eccentric exercise may be related to the increased experience of pain. Therefore the occurrence of CGRP after heavy eccentric exercise may be associated with the regulation of delayed onset muscle soreness and possibly also the stimulation of tissue regeneration.

Adult↗

General joint laxity in 1845 Swedish school children of different ages: age- and gender-specific distributions.

AIM: To evaluate general joint laxity in growing children with the aim of determining a cut-off point for joint hypermobility. METHODS: Using the Beighton score, 1845 children from 48 geographically randomly selected schools were evaluated for general joint laxity. The Beighton score evaluates the ability to perform a selection of manoeuvres involving five different joints. The children made up three different age groups (9, 12 and 15 y old) at the time of testing and were approximately equally distributed concerning age and gender in all groups. RESULTS: There were significant differences in Beighton scores concerning both age and gender. Whereas boys presented significant decreases in the degree of general joint laxity with increasing age, girls presented the highest degree of general joint laxity at the age of 15. At all ages girls had a higher degree of general joint laxity CONCLUSION: Based on this study of a normal population of Swedish school children, the normal distribution of general joint laxity as well as the limits for hypermobility is age and gender specific. It is necessary to take into consideration both age and gender if setting a cut-off point for hypermobility when evaluating general joint laxity in growing individuals.

Adolescent↗

The influence of premenstrual symptoms on postural balance and kinesthesia during the menstrual cycle.

Recent studies have indicated an increased incidence of female athletic injuries during the luteal phase and the first days of the menstrual period. The purpose of this study was to investigate whether postural sway and knee-joint kinesthesia very during the menstrual cycle, and whether premenstrual syndrome (PMS) influences postural balance and kinesthesia. A total of 13 subjects with regular menstrual cycles participated in the study. Postural sway and kinesthesia were measured in the early follicular phase, in the ovulation phase and in the mid-luteal phase. Postural sway was measured with an ankle disc placed on a Statometer, and kinesthesia was measured with a specially designed device. Menstrual cycle phases were determined by sex hormone analyses in serum and by luteinizing hormone (LH) detection in urine. The diagnosis of PMS was made prospectively using validated daily symptom ratings. Eight of 13 women were classified as having PMS. These women had a significantly greater postural sway (p = 0.002) and a greater threshold for detection of passive motion in the knee joints (p = 0.05) than women without PMS. A tendency (p = 0.06) towards greater postural sway in the mid-luteal phase was detected among women with PMS. This may explain the finding of an increased incidence of athletic injuries in the luteal phase, reported previously.

Adult↗

Self-reported hamstring injuries in student-dancers.

Dancing involves powerful movements as well as flexibility exercises, both of which may be related to specific injuries to the musculo-tendinosus tissue, e.g., the hamstring muscle complex. In this study, the occurrence of acute and overuse injuries to the rear thigh in dancers was investigated retrospectively by means of a questionnaire. All but one (n = 98) of the student-dancers (age 17-25 years) at the Ballet Academy in Stockholm participated. The results demonstrated that, during the past 10 years, every third dancer (34%) reported that they had acute injuries and every sixth dancer (17%) had overuse injuries to the rear thigh. Most (91%) of the acute injuries were subjectively located to an area close to tuber ischiadicum. The majority (88%) stated that the acute injury occurred during slow activities in flexibility training, e.g., splits, and only a few (12%) in powerful movements. Continuing problems were reported by 70% of the acutely injured dancers. Many of the dancers neglected their acute injury (14 did not even stop the ongoing dance activity) and they also greatly underestimated the recovery time. Only 4 dancers (12%) received acute medical assistance. Thus the results, based on the recollection of the subjects, indicated that stretching could induce severe strain injuries to the proximal hamstrings in dancers. Extrapolating these results to the practice, it can be recommended that stretching exercises be executed with caution in connection with dancing sessions and training, and that, information about the seriousness and acute treatment of such injuries be added to the student-dancers' curriculum.

Acute Disease↗

Sports related hamstring strains--two cases with different etiologies and injury sites.

Hamstring strains are common injuries in sports. Knowledge about their etiology and localization is, however, limited. The two cases described here both had acute hamstring strains, but the etiologies were entirely different. The sprinter was injured when running at maximal speed, whereas the hamstring strain in the dancer occurred during slow stretching. Also the anatomical localizations of the injuries clearly differed. Magnetic resonance imaging (MRI) revealed pathological changes in the distal semitendinosus muscle in the sprinter and the proximal tendon of the semimembranosus muscle in the dancer. Subjectively, both athletes severely underestimated the recovery time. These case observations suggest a possible link between etiology and localization of hamstring strains.

Adult↗

Muscle injuries associated with soccer.

Skeletal muscle has a high potential for regeneration and healing. After injuries to this tissue the treatment should focus on the limitation of the injury and optimization of the inherent regeneration capacity. This article discusses the prevalence of muscle injuries in soccer including diagnoses and complications, data from basic science, and therapeutic possibilities.

Athletic Injuries↗

Os trigonum syndrome: a clinical entity in ballet dancers.

Thirteen Swedish National classic ballet dancers were surgically treated for an "os trigonum syndrome."Their main symptom was an impingement pain in the hind foot while actively plantarflexing the ankle during ballet dancing. The surgical procedure included excision of an os trigonum or a prominent lateral posterior process of the talus, together with division of the flexor hallucis tendon sheath if it was thickened. This procedure was safe and resulted in return of the dancers to the same level of ballet dancing within 5 to 10 weeks.

Adolescent↗

Effects of chronic sympathectomy on muscle fibre composition ISO-myosin patterns, protein synthesis and calcium content in canine gracilis muscle.

We have previously reported functional and histological studies in five beagle dogs with unilateral lumbar sympathectomy. Three months later, fatiguability in the gracilis muscles was increased on the denervated sides, and this was associated with an increase in the relative distribution of FT fibres. Biochemical studies now show that these changes were associated with an increase in cytosolic protein without change in DNA content; this is consistent with an increase in cell size. There was a reduction in the proportion of slow myosin light chain isoforms from 50 +/- 7 to 34 +/- 6%. Noradrenaline levels were increased on the denervated sides but this may reflect greater vascularity. Calcium content did not correlate with fibre type but there was a positive relation with both noradrenaline content (r = 0.73; P less than 0.05) and DNA content (r = 0.84; P less than 0.05). It is concluded that sympathectomy induces several biochemical changes in skeletal muscle which constitute a change and increase in fast myosin light chain synthesis and a corresponding fibre type transformation.

Animals↗

Knee arthroscopy with local anesthesia in ambulatory patients. Methods, results and patient compliance.

Knee arthroscopy in locally anesthetized ambulatory patients has been performed by filling the knee joint with 50 ml to 60 ml of 0.5% prilocaine, with adrenaline and with additional local infiltration at the sites of puncture. During the arthroscopic procedure the joint cavity is further distended with a mixture of the same local anesthetic diluted 1:10 with physiological saline or Ringer's acetate. During a normal arthroscopy of the knee joint about 500 mg of the local anesthetic is used. In 17 patients the blood concentrations of the local anesthetic used was measured 2.5 min to 135 min after instillation. The highest plasma levels found (after 60 min to 120 min) were still 10 to 15 times lower than an acceptable upper plasma level. These low blood levels probably depend on a slow absorption and that a considerable amount of the local anesthetic is washed out after the arthroscopy. A questionnaire was sent to 278 patients who during a two year period had undergone arthroscopy as an outpatient procedure. The degree of satisfaction for the anesthetic procedure was highest for general anesthesia where 97% were completely satisfied. Sixty-four percent were satisfied when given spinal anesthesia. However, 11% had to be put to sleep due to insufficient spinal block and 12% had headaches more than one day after outpatient spinal anesthesia. Seventy-seven percent were satisfied with local anesthesia. There was no statistical difference between the degree of satisfaction after local or spinal anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Randomized trial of oral naproxen or local injection of betamethasone in lateral epicondylitis of the humerus.

A randomized pilot study, comparing oral naproxen and a single betamethasone injection, was carried out in 21 patients suffering from lateral epicondylitis of the humerus ("tennis elbow"). The naproxen dosage was 250 mg per day for two weeks. Six milligrams of betamethasone in a long-acting form was given as a local injection. To achieve "blindness," the patients receiving naproxen were also given an injection of saline into the area of maximal tenderness at the epicondyle, while the patients getting the betamethasone-injection were given oral placebo tablets. At a clinical control after two weeks, five of the ten patients receiving naproxen and five of the 11 patients receiving betamethasone injection were improved. Thus, no apparent difference in effect could be noted at an evaluation after two weeks' treatment. No significant side effects were noted with any of the treatments.

Administration, Oral↗

Steroid receptors in two types of rabbit skeletal muscle.

Radiolabeled synthetic steroid hormones and a charcoal adsorption assay were used to identify cytosolic androgen, glucocorticoid, and estrogen receptors in skeletal muscle from rabbits. The presence of the receptors was verified by saturation analysis showing low-capacity, high-affinity binding for the steroid-receptor complexes, specific for each class of steroids. The concentration of androgen and estrogen receptors were of the same magnitude, whereas the corresponding value for the glucocorticoid receptor was about tenfold higher. Comparisons of fast-twitch (the gastrocnemius/plantaris complex) and slow-twitch (soleus) muscles revealed that the latter contained higher concentrations (expressed per g of tissue wet weight) of glucocorticoid and estrogen receptors, but not of androgen receptor. Expressed per mg of soluble protein, the slow-twitch muscle contained higher concentrations of all three receptors, but when related to the concentrations of all three receptors, but when related to the concentration of DNA, only the concentration of estrogen receptor was higher in the slow-twitch muscle. Different response of the two fiber types to direct action of steroid hormones can hence be expected. The fast-twitch muscle contained a higher concentration of soluble protein, whereas the slow-twitch muscle contained higher concentration of DNA, resulting in lower protein/DNA ratio, i.e., smaller "cell units," in the latter muscle.

Animals↗

Relative binding affinity of anabolic-androgenic steroids: comparison of the binding to the androgen receptors in skeletal muscle and in prostate, as well as to sex hormone-binding globulin.

It is unclear whether anabolic steroids act on skeletal muscle via the androgen receptor (AR) in this tissue, or whether there is a separate anabolic receptor. When several anabolic steroids were tested as competitors for the binding of [3H]methyltrienolone (MT; 17 beta-hydroxy-17 alpha-methyl-4,9,11-estratrien-3-one) to the AR in rat and rabbit skeletal muscle and rat prostate, respectively, MT itself was the most efficient competitor. 1 alpha-Methyl-5 alpha-dihydrotestosterone (1 alpha-methyl-DHT; mesterolone) bound most avidly to sex hormone-binding globulin (SHBG) [relative binding affinity (RBA) about 4 times that of DHT]. Some anabolic-androgenic steroids bound strongly to the AR in skeletal muscle and prostate [ RBAs relative to that of MT: MT greater than 19-nortestosterone ( NorT ; nandrolone) greater than methenolone (17 beta-hydroxy-1-methyl-5 alpha-androst-1-en-3-one) greater than testosterone (T) greater than 1 alpha-methyl-DHT]. In other cases, AR binding was weak (RBA values less than 0.05): stanozolol (17 alpha-methyl-5 alpha- androstano [3,2-c]pyrazol-17 beta-ol), methanedienone (17 beta-hydroxy-17 alpha-methyl-1,4-androstadien-3-one), and fluoxymesterolone (9 alpha-fluoro-11 beta-hydroxy-17 alpha-methyl-T). Other compounds had RBAs too low to be determined (e.g. oxymetholone (17 beta-hydroxy-2-hydroxymethylene-17 alpha-methyl-5 alpha-androstan-3-one) and ethylestrenol (17 alpha-ethyl-4- estren -17 beta-ol). The competition pattern was similar in muscle and prostate, except for a higher RBA of DHT in the prostate. The low RBA of DHT in muscle was probably due to the previously reported rapid reduction of its 3-keto function to metabolites, which did not bind to the AR [5 alpha-androstane-3 alpha, 17 beta-diol and its 3 beta-isomer (3 alpha- and 3 beta-adiol, respectively)]. Some anabolic-androgenic steroids (only a few synthetic) bound to SHBG (1 alpha-methyl-DHT much greater than DHT greater than T greater than 3 beta-adiol greater than 3 alpha-adiol = 17 alpha-methyl-T greater than methenolone greater than methanedienone greater than stanozolol). The ratio of the RBA in rat muscle to that in the prostate (an estimate of the myotrophic potency of the compounds) was close to unity, varying only between about 0.4 and 1.7 in most cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgens↗

Correlation between chemical structure, receptor binding, and biological activity of some novel, highly active, 16 alpha, 17 alpha-acetal-substituted glucocorticoids.

The affinity for the glucocorticoid receptor in rat skeletal muscle of some glucocorticoids with a new type of 16 alpha, 17 alpha-acetal substituent has been estimated and correlated to the glucocorticoid activities in three in vivo systems in rats. Budesonide (an approximately 1:1 mixture of the C(22) epimers of 11 beta, 21-dihydroxy-16 alpha, 17 alpha-[(22R,S)-propylmethylenedioxy]-pregna-1,4-diene-3,20-dione) and the isolated (22R)- and (22S)-epimers bound to the same binding site as the potent glucocorticoids dexamethasone (DEX) or triamcinolone 16 alpha, 17 alpha-acetonide (TA), but with even higher affinity than DEX or TA, despite the lack of a 9 alpha-fluoro atom in budesonide and its epimers. The (22R)-epimer was twice as active as the (22S)-epimer, 4 times more active than TA, and 14 times more active than DEX. The introduction of a 9 alpha-fluoro atom slightly decreased the binding affinity of the (22R)-epimer of budesonide, in contrast to the positive effect of 9 alpha-fluorination of, e.g., 16 alpha, 17 alpha-acetonides. The negative influence of 9 alpha-fluorination of the (22R)-epimer was partially reversed in the 6 alpha, 9 alpha-difluorinated (22R)-epimer. Nevertheless, the fluorinated compounds were more active than DEX and TA (8 and 11 times more active than DEX, and 2 and 3 times more active than TA, in case of the 9 alpha-fluoro- and 6 alpha, 9 alpha-difluoro-derivatives of the (22R)-epimer, respectively). Budesonide is metabolized mainly to 16 alpha-hydroxyprednisolone (11 beta, 16 alpha, 17 alpha, 21-tetrahydroxy-pregna-1,4-diene-3,20-dione) and 6 beta-hydroxy-budesonide. Both metabolites were very weak competitors for the ligand-binding sites on the receptor (3% and 6% of the affinity of DEX, respectively). The affinity for the receptor in vitro was closely correlated to the topical glucocorticoid activity in vivo for the 12 steroids compared (r = 0.98; R = 0.98), which supports the contention that in vitro tests for receptor affinity are useful when screening for agonists among steroids with the present type of structures. The results on receptor-ligand interaction are in accordance with X-ray crystallographic data available for some steroids.

Animals↗

Studies on steroid receptors in human and rabbit skeletal muscle - clues to the understanding of the mechanism of action of anabolic steroids.

The mechanism of action of steroid hormones in target tissues include the binding of the steroid molecule to specific receptors in the cytoplasm. Steroid receptors may therefore be regarded as mediators of hormone action. The presence of such receptors in tissues reflects their hormone-sensitivity and the receptor levels are indicative of the relative potential for a direct hormonal action on the tissue in question. Using 3H-labeled synthetic ligands and a charcoal adsorption assay, the presence of specific androgen, glucocorticoid and estrogen (in rabbits only) receptors was demonstrated in human and rabbit skeletal muscle cytosol. These tissues can therefore be regarded as targets for these steroids. Scatchard analysis was then used to quantitate the receptors in muscle in different conditions. In back muscle of scoliotic patients, the concentrations of androgen and glucocorticoid receptors were similar on the convex and concave sides, except the concentration of glucocorticoid receptors (per g of wet weight), which was higher on the convex side. The tissue concentration (per g of wet weight) of glucocorticoid and estrogen receptors (but not of androgen receptor) was higher in rabbit soleus (slow-twitch) muscle than in the gastrocnemius/plantaris (fast-twitch) muscle complex. When the concentrations were related to the number of nuclei (i.e. expressed per mg of DNA), however, only the estrogen receptor concentration differed between the muscles (higher in soleus). Muscle atrophy in rabbit gastrocnemius muscle was induced by tenotomy or denervation and led to similar changes with an increase with time in androgen and glucocorticoid receptor levels (expressed per g of wet weight or per mg of protein) and a concomitant loss of muscle weight and protein. The total muscle content of receptors or the receptor concentration expressed per mg of DNA were also increased, but to a lesser extent. Synthetic anabolic-androgenic steroids can act directly on skeletal muscle in view of their capacity to bind to the androgen receptor as shown in the present study. Relative binding affinities of anabolic-androgenic steroids to the androgen receptor were similar in rabbit and rat skeletal muscle and in rat prostate. The protein/DNA ratio in the muscle samples was used as an estimation of the size of the "functional DNA-unit". The results indicate that slow-twitch fibers have smaller "DNA units", but also that muscle atrophy causes a decrease of the size of the "DNA unit".(ABSTRACT TRUNCATED AT 400 WORDS)

Androgens↗