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Biomedical subjects

T Videman

Publications and source records attributed to T Videman.

At least 91 records · Page 5Linked to original sources
PubMed1982

Experimental osteoarthritis in the rabbit: comparison of different periods of repeated immobilization.

The objective of this study was to compare the degree of osteoarthritis caused by different periods of repeated immobilization and mobilization. Existing knowledge of the pathogenic factors causing osteoarthritis is deficient, but it is well known that long-term immobilization produces degenerative joint changes. In this experimental study it is shown that short repetitive periods of immobilization also induce osteoarthritis. The results can be summarized as follows: immobilization, periodic or continuous, over more than 30 days will lead to progressive osteoarthritis. The range of motion after periodic immobilization depends more on the total immobilization time than on the duration of either the immobilization or mobilization periods. Even an immobilization period of 4 days had a cumulative effect in producing osteoarthritis. An interval of 4 weeks between immobilization periods did not prevent immobilization from causing osteoarthritis. It can be assumed that all situations which lead to the immobilization of a joint can cause osteoarthritis changes. Radiology, photography, and histology all showed some degree of degenerative changes also in the contralateral non-immobilized knee.

Animals↗
PubMed1982

Shortwave diathermy effects on 35S-sulfate uptake and glycosaminoglycan concentration in rabbit knee tissue.

The effect of shortwave diathermy on glycosaminoglycan metabolism in different connective tissues of rabbit knee was studied by both autoradiography and radioactivity measurements and quantification of the separated glycosaminoglycans. Of 30 rabbits used, 12 received 100W shortwave diathermy to the right knee 10 minutes a day for 5 days. Autoradiography clearly showed a higher uptake of 35S-sulfate by the capsular tissues of the knee treated with shortwave diathermy than in the contralateral knee. The most prominent feature of the biochemical analysis was the increase in the galactosamine (43%) and glucosamine (26%) concentrations of the collateral ligament glycosaminoglycans of the treated knee.

Animals↗
PubMed1982

Effect of ultrasound on glycosaminoglycan metabolism in the rabbit knee.

The effect of ultrasound therapy on glycosaminoglycan metabolism in articular cartilages, menisci and capsular tissues of rabbit knee was studied using both autoradiography and biochemical methods. Glycosaminoglycans were examined by determining the uronic acid, glucosamine and galactosamine contents and the specific radioactivity of galactosamine of the purified substances. A total of 31 rabbits were used, 13 of which received ultrasound treatment, power 1 W/cm2, to the right knee 5 minutes a day for five days. The specific radioactivity in separated glycosaminoglycans of the medial collateral ligament of the treated knee was 69% higher than that of the controls and 36% higher than that of the contralateral ligament. The same effect was seen in autoradiography. Glycosaminoglycan concentrations of articular cartilage, menisci and collateral ligament were unaltered. The result may indicate that the main effect of ultrasound therapy is on the capsular tissues of a healthy joint.

Animals↗
PubMed1981

[3H]proline incorporation and hydroxyproline concentration in articular cartilage during the development of osteoarthritis caused by immobilization. A study in vivo with rabbits.

Proline metabolism in vivo was studied during the development of immobilization osteoarthritis in rabbits. Collagen content was measured as the hydroxyproline concentration of the tissue in question. The incorporation of [3H]proline was used as the indicator for total protein synthesis; collagen synthesis rate was estimated from measurements of the specific radioactivity of hydroxyproline. Cartilage samples from knee and hip joints were analysed after 3, 7, 11, 18, 35 and 56 days of immobilization. The total protein and collagen synthesis rates of the immobilized legs increased and reached a maximum after 11-35 days. Although they decreased thereafter, these rates remained elevated to the end of the experiment. A slight increase in the synthetic activity of the non-immobilized contralateral legs was also detected after 7--18 days of immobilization. The isotope incorporation was markedly higher in tibial marginal tissue than in weight-bearing cartilage. In spite of the increased synthesis, no clear changes were found in the collagen content of the tissues studied during the experiment.

Animals↗
PubMed1981

Changes in compression and distances between tibial and femoral condyles during immobilization of rabbit knee.

The compression forces and the distances between tibial and femoral condyles were measured during the development of osteoarthritis produced by immobilizing rabbit knees. The compression was measured in both the immobilized and non-immobilized knees with a sub-miniature pressure sensor. Compression increased up to threefold during the four first weeks of immobilization and decreased thereafter to below the initial level. These results give one explantation why immobilization produced degenerative joint changes; they also support the hypothesis that capsular tissues can play a role in the pathogenesis of osteoarthritis.

Animals↗
PubMed1981

Reliability of a vibration test in screening for predisposition to tenosynovitis.

The reliability of a vibration test has been studied in terms of its feasibility for screening for predisposition to tenosynovitis in an occupational health setting. In a worker population with a high prevalence of tenosynovitis the specificity and sensitivity of the method in the best cases were 68% and 50%, respectively. In an apparently healthy population there were significant interindividual differences; but in successive trials the same individual could have index values indicating both a predisposition and a lack of predisposition for tenosynovitis. The index value seems to be dependent on the temperature of the test room. It was concluded, in contrast to earlier results, that the vibration test is, of no value in screening for a predisposition to tenosynovitis in an occupational health setting.

Adult↗
PubMed1981

Glycosaminoglycan metabolism in experimental osteoarthritis caused by immobilization. The effects of different periods of immobilization and follow-up.

Glycosaminoglycan metabolism at different developmental stages of osteoarthritis provoked by immobilization was studied in rabbits. Tissue concentrations and the specific radioactivity of glycosaminoglycans (GAG) after a long immobilization (IZ) period (12 weeks) without follow-up, and a moderate IZ time (4-7 weeks) with a long follow-up period (average 22 weeks) were compared with the results obtained after a short IZ time (17 days). In tibial weight-bearing cartilage the specific 35S-activity had increased and the galactosamine, glucosamine and uronic acid concentrations had decreased in all the IZ groups examined. In the marginal cartilage, the menisci and the collateral ligament, the specific radioactivity and GAG concentrations had decreased or were normal after a long IZ with or without follow-up, although they were markedly elevated after a short IZ time. THe depletion of GAG correlated roughly with the IZ and follow-up times, except for periodically immobilized rabbits. In long-term "chronic" disease the specific radioactivities and GAG concentrations were depressed on the contralateral, non-IZ sides. The changes in the non-IZ knee are discussed. In studies of experimental osteoarthritis it is important to determine the developmental stage of the disease to be studied.

Animals↗
PubMed1980

Surface changes in the articular cartilage of rabbit knee during immobilization. A scanning electron microscopic study of experimental osteoarthritis.

Osteoarthritis was produced by the immobilization of rabbit knees in extension for 1--8 weeks (with a subsequent mobilization period of 0 or 8 weeks). The development of articular surface changes in the tibia, the femur and the patella was examined with scanning electron microscopy (SEM). During the development of osteoarthritis the normal undulations and fine regular fibre network disappeared, the number of fibres and the variation in the thickness of the fibre bundles increased, and scaly irregularities appeared. Some degenerative changes in the contralateral, non-immobilized hind limb also appeared. The normal features of the articular surface of the patella differed from that of the tibial and femoral condyles. The changes seen with SEM correlated well with histological and biochemical results of earlier studies, but at 1 week of immobilization, the SEM changes were more readilly apparent than the histological changes. The SEM method seems to be useful for the study of articular surfaces; however, the area studied must be defined.

Animals↗
PubMed1979

Glycosaminoglycan metabolism of the medial meniscus, the medial collateral ligament and the hip joint capsule in experimental osteoarthritis caused by immobilization of the rabbit knee.

A study was made of glycosaminoglycan metabolism in experimental osteoarthritis caused by immobilization of the rabbit knee in extension. Samples from the medial meniscus, the medial collateral ligament of the knee and the hip joint capsule were obtained and analysed after 2, 6, 10, 17, 30 and 87 days of immobilization, samples from the mobile limb serving as controls. The tissue concentrations of glycosaminoglycans were determined from measurements of hexosamine and uronic acid after prior papain proteolysis and subsequent purification. The uptake of 35S-sulphate (DPM/microgram hexosamine) was used as an indicator of the synthesis rate of sulphated glycosaminoglycans. In both early and advanced immobilization osteoarthritis, the synthesis rate and the content of glycosaminoglycans were increased in all tissues.

Animals↗
PubMed1979

Osteoarthritis of the knee in the rabbit produced by immobilization. Attempts to achieve a reproducible model for studies on pathogenesis and therapy.

In order to obtain a reproducible experimental model of osteoarthritis a method of immobilizing the rabbit's knee in extension by means of plastic splint was developed. The right knees of the rabbits were immobilized for periods varying from 4 days to 24 weeks. With the left knees as controls the knees were studied in a variety of ways among these being radiography (126 rabbits), histological sections stained with Alcian Blue (88 rabbits), analysis of 35S-sulphate uptake (22 rabbits) and 35S-autoradiography (6 rabbits). In 27 rabbits the regaining of mobility after immobilization was studied. After 5-6 weeks of immobilization most of the knees showed moderate or severe changes including loss of articular cartlilage and osteophyte formation. Immobilization of the rabbit's knee by this method provokes a fairly easily reproducible type of degenerative joint disease showing similarities to advanced osteoarthritis as seen in humans.

Animals↗
PubMed1979

The effect of beta-blockade in ski-jumpers.

Nine ski-jumpers from the Finnish Olympic team were given 40 mg of oxprenolol or placebo on a cross-over double-blind basis when participating in four internal competitions. Six ski-jumpers improved their performances when on oxprenolol. The improvement was mainly seen in the lengthening of the jumps. The tachycardia, apparently evoked by the emotional and physical strain associated with the actual jump, approached rather extreme levels (up to 170 beats/min) immediately after landing. The enhancement in the heart rate was effectively prevented by a gentle beta-blockade. The most common unwanted effect recorded was numbness in the legs after climbing up to the tower platform, reported 9 times out of 18 possible occasions after oxprenolol but never after placebo. The fact that three of the jumpers (out of 9) performed worse when on oxprenolol makes the toxic/benefit ratio (1:2) unacceptably high for the medication.

Double-Blind Method↗
PubMed1979

Effects of motion load changes on tendon tissues and articular cartilage. A biochemical and scanning electron microscopic study on rabbits.

The motion load of rabbits was increased by treadmill running during a 5-d period. One group ran on a level surface, while the other ran uphill. After the running, the glycosaminoglycan metabolism and scanning electron microscopic photographs of different tendon, ligament and cartilage samples were analyzed. Uphill running decreased the glycosaminoglycan metabolism of articular and costal cartilage. The clearest irregularities of articular cartilage studied by scanning electron microscopy were also seen in the uphill running group. Increasing the motion load increased the glycosaminoglycan synthesis of stretched tendons. The possible combination of general inhibitory and local stimulating effects is discussed.

Animals↗
PubMed1978

Inhibition of osteogenesis by bone mass in diffusion chamber cultures.

The effect of increased bone mass on osteogenesis was studied using the diffusion chamber culture of mouse distal radius as an experimental model. Two distal thirds of a mouse's radii were cultured in separate diffusion chambers in a recipient mouse; one chamber contained only a distal radius, but the other contained a distal radius plus two proximal radii and two ulnae. The DNA synthesis of osteogenetic cells was significantly inhibited in cultures with excess bone mass. The mean inhibition in labelling indices of epiphyseal plate chondrocytes was 27% and of periosteal cells 40%. The nature of this inhibition seems to be specific.

Animals↗
PubMed1978

Frequent users of doctor services in a small rural community.

Thirty-six per cent of the visits to doctors in a small rural community were made by the 6% of the population having the most diseases or symptoms. About 90% of the population accounted for about one-half of the medical services provided by the Kuusamo doctors; the other half was taken up by the 10% of the inhabitants in greatest need of medical attention. Adults consulted a doctor 2.1 times a year on the average. The most common reasons for consultations were respiratory diseases (23%), diseases of the genito-urinary system (16%) and accidents (14%).

Adult↗
PubMed1978

Glycosaminoglycan metabolism in experimental osteoarthrosis caused by immobilization.

A study was made of glycosaminoglycan metabolism of articular cartilage in developing experimental osteoarthrosis caused by immobilization of the rabbit knee. Cartilage samples from various sites in the knee and hip joints were analysed, samples from the mobile limb serving as controls. The concentration of glycosaminoglycans in the tissue was measured by determinations of hexosamine and uronic acid after prior papain proteolysis and subsequent purification. The uptake of 35S-sulphate was used as an indicator of the synthesis rate of sulphated glycosaminoglycans. Metabolic changes characteristic of osteoarthrosis, i.e., glycosaminoglycan depletion and increased uptake of 35S-sulphate, were found in tibial weight-bearing and femoral condylar cartilages. Net synthesis of glycosaminoglycans occurred in the tibial marginal cartilage.

Animals↗