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Biomedical subjects

J Ekstrand

Publications and source records attributed to J Ekstrand.

At least 127 records · Page 7Linked to original sources
PubMed1985

Renal clearance of fluoride in children and adolescents.

Renal function and fluoride excretion have been studied in 38 children. The children were divided into three groups according to their glomerular filtration rate: normal (92 to 136 mL/min/1.73 m2 of body surface area [BSA]), low (less than 92 mL/min/1.73 m2 BSA, and super-normal (greater than 136 mL/min/1.73 m2 BSA). Standard clearance technique with infusion of inulin and p-aminohippuric acid during water diuresis was used. Mean renal fluoride clearance was 45.0 +/- 9.8 (SD) mL/min in the group of children with normal glomerular filtration rates and 31.4 +/- 8.8 mL/min in the group with low glomerular filtration rates. This difference was statistically significant. There was a close linear relationship between renal fluoride clearance and glomerular filtration rate, urinary flow, and free water clearance. The fractional fluoride excretion did not differ between the groups. About 60% of the filtered fluoride was reabsorbed. No evidence for tubular secretion exceeding the reabsorption could be found. The results suggest that children have lower renal fluoride clearance rates than adults and indicate that a moderate impairment of the renal function could lead to increased retention of fluoride.

Adolescent↗
PubMed1985

Duration of stretching effect on range of motion in lower extremities.

The duration of the effect of contract-relax stretching on range of motion (ROM) in the lower extremities was measured on eight male volunteers. The stretching procedure was performed as one isometric contraction, followed by relaxation and then a passive extension of the muscle being stretched. The treated muscle groups were the adductors, hamstrings, rectus femoris, iliopsoas, gastrocnemius, and soleus. The total stretching time was 15min. Six ROMs were tested 0, 30, 60, and 90min after the stretching procedure. There was a significant increase in hip abduction (+17% +/- 3), knee flexion (+4% +/- 1), hip flexion (+4% +/- 2), ankle dorsiflexion with knee flexed (+18% +/- 7), and ankle dorsiflexion with knee straight (+16% +/- 5). The increase remained for 90min for all ROMs except for ankle dorsiflexion with the knee straight.

Humans↗
PubMed1984

Muscle strength and flexibility in different positions of soccer players.

One-hundred eighty soccer players were tested for muscle strength in knee extension and knee flexion and for flexibility in the lower extremity. The strength measurements were done with a Cybex II isokinetic device (Lumex, Bay Shore, New York). The range of motion (ROM) was measured according to a method described by Ekstrand et al. (1982). The players were divided into groups according to their player position: goalkeepers, defenders, midfielders, and forwards. The results showed a significantly higher knee extensor torque in goalkeepers and defenders than in forwards (P less than 0.05). The knee flexion/knee extension ratio (H/Q ratio) was significantly higher for forwards compared to goalkeepers (P less than 0.001) and defenders (P less than 0.01). The goalkeepers were significantly more flexible than the other players in hip flexion (P less than 0.001), knee flexion (P less than 0.01), and ankle dorsiflexion (P less than 0.001).

Adolescent↗
PubMed1984

Stabilometry in functional instability of the ankle and its value in predicting injury.

Stabilometry is an objective method used for studying postural equilibrium quantitatively. Stabilometric recordings were made in 127 soccer players to demonstrate functional instability of the ankle joint. The presence of previous ankle joint injuries, i.e., sprains or fractures, was documented. Reference values for stabilometry were obtained from a group of 30 normally-active non-soccer players without a history of injury to the ankle joint. A pathological stabilometric value was defined as one exceeding the mean value of the reference group by 2 SD. In players with a history of previous ankle joint injury no increased postural sway was found. On the other hand, players showing abnormal stabilometric values ran a significantly (P less than 0.001) higher risk of sustaining an ankle injury during the following season compared to players with normal values. Players with a history of previous ankle joint injury did not run a higher risk compared to players without previous injury. The findings indicate that an ankle joint injury did not result in a persistent functional instability; however, such instability did increase the risk of ankle joint injury.

Adolescent↗
PubMed1983

Renal excretion of fluoride during water diuresis and induced urinary pH-changes in man.

Fluoride renal clearance (CF) was studied in young healthy subjects with standard clearance technique following administration of 3 mg F as a 30-min constant infusion. High urinary flow rates were induced and experiments were performed under both urinary alkaline and acidic conditions. The data showed that a high urinary flow resulted in maximum fluoride clearance. High water diuresis may therefore be an important part in the treatment of acute fluoride intoxication.

Adult↗
PubMed1983

The avoidability of soccer injuries.

One hundred eighty players in a male soccer division were followed prospectively for 1 year to assess etiologic factors in soccer injuries. Range of motion and muscle strength in the lower extremities were measured in a preseason test. All injuries during 1 year were examined by the same orthopaedic surgeon. 42% of the injuries were considered to be due to player factors, such as joint instability, muscle tightness, inadequate rehabilitation, or lack of training. Ankle sprains were commoner in players with previous ankle sprains or clinical instability. 35% of the moderate (absence from practice greater than 1 week, less than 1 month) or major (absence greater than 1 month) injuries were preceded by minor (absence less than 1 week) injuries, reflecting inadequate rehabilitation. Players sustaining knee sprains not due to collision had reduced muscle strength in the injured leg. No other strength differences between injured and uninjured players were found. 63% of players had tight muscles. Strains more commonly affected players with muscle tightness. 71% of the injuries proved to be explicable by and associated with player factors, equipment, playing ground, or rules.

Adult↗
PubMed1983

The relationship between plasma fluoride, urinary excretion rate and urine fluoride concentration in man.

The fluoride concentration in urine is commonly used for monitoring fluoride exposure, e.g., in aluminium plants. Hitherto this parameter does not seem to have been related to the actual fluoride concentration in plasma following fluoride exposure. In the present study the fluoride concentration in urine, the urinary excretion rate of fluoride and the fluoride concentration in plasma have been studied in five volunteers after intake of 10 mg of fluoride in the form of sodium fluoride (NaF) tablets. In pharmacokinetic analyses of the data calculation of the half-life of fluoride from plasma data and from the urinary excretion rate yielded almost identical results; 5.78 hours (plasma) and 5.11 hours (urine). It was found that plasma fluoride levels were correlated with the fluoride concentration in urine (r = .7532; n = 70), but even more with the urinary excretion rate of fluoride (r = .9651; n = 63). The data suggest that plasma fluoride levels or urinary excretion rates of fluoride may give a more correct picture of occupational fluoride exposure than fluoride concentrations in urine.

Adult↗
PubMed1983

Cyclic AMP in urine, kidney and liver following long-term administration of fluoride to rats.

Rats were exposed to fluoride (F) for up to 8 weeks through the drinking water containing 100 p.p.m. F. Urine samples were regularly collected, together with tissue samples of liver and kidney at termination. All samples were assayed for cyclic AMP. No F-effect was found on liver or kidney levels of cyclic AMP. In the urine from the F-exposed rats there was an overall increase in the cyclic AMP concentration, but a decreased or unaffected 24 hrs urinary excretion of cyclic AMP. However, the F-exposed rats exhibited a considerably lower diuresis than the control animals. Because a significant negative correlation was found between diuresis and urinary concentration of cyclic AMP, the material was corrected to similarity in the mean diuresis between the two groups. Then no effect of F-exposure could be detected either in the urinary concentration or the daily excretion of cyclic AMP.

Animals↗
PubMed1983

No effect of prolonged fluoride exposure on cytochrome P-450 and associated monooxygenases or on the level of polyamines in the rat.

When exposing rats to drinking water containing 100 p.p.m. fluoride for 8 weeks, no effect could be detected in biochemical parameters of the liver, such as the concentrations of the polyamines putrescine, spermidine and spermine; the levels of microsomal protein and cytochrome P-450; or the activities of two associated monooxygenases, aryl hydrocarbon hydroxylase and ethylmorphine N-demethylase. Neither was there any increase in plasma glutamic-oxalacetic transaminase indicative of liver damage.

Animals↗
PubMed1983

Soccer injuries and their mechanisms: a prospective study.

In order to study the incidence and mechanisms of injury in soccer and to recommend prophylactic measures, 180 players in a senior male soccer division were followed prospectively for 1 yr. Attendance records for games and practice sessions were kept, and all injuries were examined and treated by the same orthopaedic surgeon. One hundred twenty-four players incurred 256 injuries, mostly sprains and strains of the lower extremities. Of these, 62% were considered minor with ankle sprains being the most common (17%), while 11% were considered major with knee ligament sprains being the most frequent (32%). Overuse injuries were most frequent in the preseason training period. Traumatic leg injuries involved players with inadequate or no shin guards. Of the traumatic knee injuries, 11 of 18 (61%) occurred during a collision; non-contact knee injuries were frequently seen in those players with a history of knee injury and existing instability. Study of injury sequence disclosed that a minor injury was often followed within two months by a major one. In addition, with severe injuries incurred during fouls, the individual causing the penalty was injured. This prospective study suggested that those with knee instability and those allowed to resume play with poorly rehabilitated or clinically unhealed injuries are more apt to sustain further injury. Some injuries can be avoided by using better equipment and by observance of the rules.

Adult↗
PubMed1982

Renal clearance of fluoride in a steady state condition in man: influence of urinary flow and pH changes by diet.

In order to study fluoride renal clearance, four subjects were given 3 mg fluoride as sodium fluoride tablets every 6 hrs for 60 hrs during two separate periods - during production of acid urine induced by a protein rich diet and during production of alkaline urine obtained by giving a vegetarian diet. Plasma and urine were collected every third hour for 72 hours during each experiment. In the protein rich diet period urinary pH was significantly lower than when the subjects were maintained on the vegetarian diet. Lower urinary output of fluoride during the protein rich diet experiment was recorded, however, the difference was not significant. Plasma fluoride at steady state was almost the same during both experiments. Renal fluoride clearance was significantly correlated to urinary pH in both types of experiments. When renal fluoride clearance was plotted versus urinary flow, the correlation was only significant during alkaline conditions. The average renal clearance was not significantly different between the two sets of experiments. It may be concluded, that pH and diuresis both influences fluoride renal clearance. Moreover, the results suggests that dietary components as such, influence renal clearance of fluoride in some way or another.

Adult↗