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Biomedical subjects

I Kiviranta

Publications and source records attributed to I Kiviranta.

At least 55 records · Page 3Linked to original sources
PubMed1995

Proteoglycan depletion and size reduction in lesions of early grade chondromalacia of the patella.

OBJECTIVE: To determine the content and molecular size of proteoglycans (PGs) in patellar chondromalacia (CM) and control cartilages as a first step in investigating the role of matrix alterations in the pathogenesis of this disease. METHODS: Chondromalacia tissue from 10 patients was removed with a surgical knife. Using identical techniques, apparently healthy cartilage of the same site was obtained from 10 age matched cadavers (mean age 31 years in both groups). Additional pathological cartilage was collected from 67 patients with grades II-IV CM (classified according to Outerbridge) using a motorised shaver under arthroscopic control. The shaved cartilage chips were collected with a dense net from the irrigation fluid of the shaver. The content of tissue PGs was determined by Safranin O precipitation or uronic acid content, and the molecular size by mobility on agarose gel electrophoresis. RESULTS: The mean PG content of the CM tissue samples with a knife was dramatically reduced, being only 15% of that in controls. The cartilage chips collected from shaving operations of grades II, III, and IV CM showed a decreasing PG content: 9%, 5%, and 1% of controls, respectively. Electrophoretic analysis of PGs extracted with guanidium chloride from the shaved tissue samples suggested a significantly reduced size of aggrecans in the mild (grade II) lesions. CONCLUSION: These data show that there is already a dramatic and progressive depletion of PGs in CM grade II lesions. This explains the softening of cartilage, a typical finding in the arthroscopic examination of CM. The PG size reduction observed in grade II implicates proteolytic attack as a factor in the pathogenesis of CM.

Adult↗
PubMed1994

Articular cartilage thickness and glycosaminoglycan distribution in the young canine knee joint after remobilization of the immobilized limb.

The recovery of articular cartilage from atrophy induced by joint immobilization was investigated in immature dogs. In a previous study, we showed that 11 weeks of immobilization of the knee (stifle) joint of young dogs reduced the concentration of articular cartilage glycosaminoglycans (GAGs) by 13-47%. In the present study, right hindlimbs from six female beagles were immobilized for 11 weeks, as in the previous study, and then were remobilized for 15 weeks. Cartilage from the knee joint was compared with cartilage from nonimmobilized knees of eight age-matched control beagles. Histological samples taken from 11 different locations of the knee joint were stained with safranin O, and microspectrophotometry was used to demonstrate distribution of GAGs in the tissue. After remobilization, GAG concentration was restored in the patellofemoral region and tibial condyles. On the summits of the femoral condyles, and especially at the periphery of the femoral condyles, GAG concentration remained 8-26% less than the control values. On the summits, the thickness of the uncalcified cartilage was as much as 15% less than in the age-matched controls. Consequently, the changes induced by unloading were reversible to a great extent, but a full restoration of articular cartilage was not obtained at all sites of the knee joint within the 15 weeks of remobilization. Immobilization of the skeletally immature joint therefore may affect the development of articular cartilage in such a way that very slow recovery or permanent alterations are induced.

Animals↗
PubMed1994

Lateral release in chondromalacia patellae using clinical, radiologic, electromyographic, and muscle force testing evaluation.

Lateral release (division of the lateral retinaculum of the patella) is a common operative procedure to improve alignment of the patella in patients with chondromalacia patellae. We investigated the effects of lateral release using clinical follow-up and studied the changes in the radiologic measurements of the patellar alignment and electromyographic function of the stabilizing muscles of the knee, as well as using muscle-force tests of the thigh. The study included 75 patients. Diagnostic arthroscopy was done for all patients. In 42 patients with obvious incongruency of the patellofemoral joint observed at arthroscopy, open division of the lateral patellar retinaculum was performed in addition to arthroscopy. Four years after surgery, the results showed that although division of the lateral retinaculum of the patella reduced lateral patellar tilting and lateral patellar displacement, the postoperative physical capacity of the patients was not improved. Lateral release did not impair the electrical activity of thigh muscles. The Lysholm scores of the lateral release group and the control group were equal after four years.

Adult↗
PubMed1994

Effects of different irrigation liquids and times on articular cartilage: an experimental, biomechanical study.

To characterize the suitability of different solutions [6% Dextran, 5% sorbitol (I); 5% fructose (II); 5% mannitol (III); Ringer's solution (IV)] for arthroscopy, bovine knee articular cartilage specimens (n = 52) were immersed for 0, 2, 4, or 20 h before indentation creep testing, known as a sensitive probe for tissue degeneration. Immersion in liquid I for up to 20 h produced significant softening of articular cartilage [p < 0.05, Friedman two-way analysis of variance (ANOVA)]. Liquids II-III produced no statistically significant changes in the deformational characteristics of articular cartilage. After 2 h of immersion in liquid IV deformation increased and remained elevated over the observation period (p < 0.05, Friedman two-way ANOVA). Based on these results, the first and most remarkable softening of cartilage took place with Ringer's solution as compared with nonionic solutions. Therefore, the nonionic solutions, such as 5% fructose or mannitol, may have potential for use as an irrigation liquid during arthroscopic procedures.

Analysis of Variance↗
PubMed1994

Softening of the lateral condyle articular cartilage in the canine knee joint after long distance (up to 40 km/day) running training lasting one year.

The effects of long distance running training (up to 40km/day) on the biomechanical properties of young canine articular cartilage were investigated using in situ indentation creep technique. The stiffness of articular cartilage was determined in the form of instantaneous and equilibrium shear moduli. The rate of cartilage deformation was also computed. Microspectrophotometric and polarized light microscopic analyses were made for determination of local glycosaminoglycan content and collagen organization, respectively. During a period of one year, the runner dogs (n = 10) underwent a gradually increased treadmill exercise up to 40 km/day, while the littermate control dogs (n = 10) lived normally in their cages. The equilibrium shear modulus of articular cartilage decreased significantly by 12 to 14% (p < 0.05) in the lateral, but not in the medial, condyles of femur and tibia. In the lateral condyles of the runner dogs, the deformation rate of cartilage increased by 16% (p < 0.05). Consequently, the articular cartilage response to running training was site-dependent. The simultaneous changes of the equilibrium shear modulus or the retardation time spectrum and the glycosaminoglycan content confirm the key role of proteoglycans in modulating the cartilage equilibrium stiffness and creep rate. The changes in the instant shear modulus appeared to be predominantly related to the alterations in the organization of the superficial collagen network. Although the running training did not create cartilage damage, we assume that the softening of the cartilage may with time jeopardize the ability of articular cartilage to maintain its normal structural and functional properties.

Animals↗
PubMed1994

Proteoglycan and collagen alterations in canine knee articular cartilage following 20 km daily running exercise for 15 weeks.

The composition of extracellular matrix was studied at 11 different sites in the knee (stifle) articular cartilage of young beagle dogs after running exercise of 15 weeks, 20 km/day. Water content was significantly elevated by 5-17% in the patellofemoral groove and in anterior and intermediate sites on the lateral condyle of femur. Collagen content was decreased by 14 to 20% in the same sites of the lateral condyle. Proteoglycan (PG) content was not significantly changed except in the posterior edge of the medial condyle of femur with a 30% decrease. The proportion of PGs capable of reaggregation with hyaluronan was increased in tibial and femoral surfaces (mean of all sites +18%). Also, the aggregating PG monomers were larger at all sites, as studied by agarose gel electrophoresis. The chondroitin-6 to 4-sulphate ratio was reduced at the summits of femoral condyles and patella by 10 to 25%, but increased in the patellar surface of femur and tibial medial condyle, fitting to a previous finding that strenuous running depleted proteoglycans at the summits of femoral condyle from the superficial zone that is rich in chondroitin-6-sulphate. The increased water content, accompanied with a decreased concentration of collagen in the lateral femoral condyle, suggests loosening of the collagenous framework, an idea compatible with an earlier notion of superficial depletion of PGs in these sites, and possibly predisposing to degeneration. The size increase of the aggregating PGs probably indicate that a larger proportion of matrix PGs were newly synthesized and hence the turnover rate of the PGs was enhanced. It is concluded that the strenuous running program induced locally restricted changes resembling early degeneration of articular cartilage, while simultaneously caused alterations that suggest a general stimulation of proteoglycan metabolism.

Animals↗
PubMed1993

Long-distance running causes site-dependent decrease of cartilage glycosaminoglycan content in the knee joints of beagle dogs.

OBJECTIVE: To study the effects of a long-term (1-year) program of running exercise (up to 40 km/day) on the thickness and glycosaminoglycan (GAG) content of articular cartilage in the knee and humeral head cartilage of young dogs. METHODS: Samples for histologic analysis were obtained from 12 different locations of the joints. We conducted a detailed, area-specific analysis, measuring the thickness of articular cartilage and analyzing the distribution of Safranin O stain that binds stoichiometrically to GAG as determined by quantitative microspectrophotometry. RESULTS: Running exercise decreased the GAG content of the uncalcified articular cartilage in the weight-bearing summits of the femoral condyles by 5-13% (P < 0.05), while at margins of these areas the GAG content was equivalent to control levels. In the lateral condyle of the femur, the reduction was most prominent in the superficial zone (up to 28% decrease; P < 0.05), and extended into the intermediate zone (11% decrease; P < 0.05). GAG content was also significantly reduced in the superficial zone at the lateral condyle of the tibia and the head of the humerus, by 35% (P < 0.01) and 15% (P < 0.05), respectively. Running did not alter GAG concentration in the patellofemoral region. CONCLUSION: The GAG depletion caused by 40-km/day running exercise is restricted to prominent weight-bearing areas of the joint and begins from the superficial cartilage without signs of degeneration. The different degree and type of joint loading can explain the site-dependent cartilage response to long-distance running. The loss of GAGs was possibly due to breakdown of proteoglycans, which could not be compensated for by neosynthesis of molecules. With time, this may affect the condition of articular cartilage, especially if the joint is exposed to loading for lengthy periods.

Animals↗
PubMed1993

Proteoglycan synthesis in canine intervertebral discs after long-distance running training.

The alterations and distribution of proteoglycan (PG) synthesis in the intervertebral discs of young dogs exercised with long-distance running (40 km/day) were studied with a method based on image analysis of tissue sections. Ten dogs were run on a treadmill daily for 55 weeks, and 10 dogs from the same litters served as controls. The daily running distance gradually was increased to 40 km and was maintained at that level for the final 15 weeks. Midsagittal disc segments C7-T1, T8-9, and L1-2 were labeled with 35SO4, and histological sections of the segments were apposed against autoradiographic film to determine the synthesis of PGs. Next, the same sections were stained with safranin O to estimate possible alterations in PG concentration. The radiographs and stained sections were digitized with a flatbed scanner and measured by image analysis. The lumbar discs of runners displayed a significantly lower rate of 35SO4 incorporation, while a tendency toward enhanced incorporation was seen in the cervical and thoracic discs. Safranin O staining showed a pattern just opposite to 35SO4 incorporation: decreased staining in the cervical and thoracic discs and increased staining in the lumbar discs of the runners. The results demonstrate qualitatively different influences of long-term running training on PG metabolism at the cervical, thoracic, and lumbar levels in young dogs.

Animals↗
PubMed1993

Flat bed scanner in the quantitative assay of 35SO4-incorporation by X-ray film autoradiography of intervertebral disc sections.

A rapid quantitation of proteoglycan synthesis distribution in intervertebral disc and endplates is described. Tissue blocks of disc (C7-Th1) in the midsagittal plane from ten female beagles were incubated in the presence of 35SO4 and prepared as histological slides. For comparison, sulphate incorporation rates in the C5-C6 discs were assayed by liquid scintillation. Autoradiographic film exposed against the labelled sections was developed and digitized for image analysis using a 256 grey level flat bed table scanner connected to a microcomputer. The film density versus dpm (disintegrations per minute) calibration was performed using a set of 35SO4-labelled glycosaminoglycan standards applied on the same film. Since section thickness, dpm calibration of the film density and the specific activity of sulphate in the medium were known, the incorporations per tissue volume could be calculated. The average incorporation rates of the anterior and posterior annulus fibrosus, nucleus pulposus and vertebral endplates were 5.2 +/- 0.9, 5.2 +/- 0.8, 4.5 +/- 0.6 and 4.1 +/- 0.8 pmol/mm3 per h (+/- SE, n = 10), respectively and closely corresponded to those obtained by liquid scintillation. This method offers a convenient and reproducible way to measure the rate of proteoglycan synthesis in large tissue sections but also in thin cartilaginous tissues such as the vertebral endplate.

Animals↗
PubMed1993

Effect of running exercise on proteoglycans and collagen content in the intervertebral disc of young dogs.

Collagen and proteoglycans in the intervertebral disc (LI-II) of young beagle dogs (age 55 weeks) were analyzed following a 15 weeks' daily 20 km running training on a treadmill with 15 degree uphill inclination. In nucleus pulposus no statistically significant alterations were found in the content of proteoglycans or collagen. In annulus fibrosus the total tissue wet weight and total amount of collagen (hydroxyproline) increased by 34-36% in the runners as compared to age-matched, untrained controls. Since the total amount of proteoglycans did not increase, the annulus fibrosus became relatively depleted of proteoglycans, as indicated by the 27% reduction in uronic acid concentration, expressed either per wet weight or hydroxyproline. The average molecular size of the remaining nonaggregating proteoglycans was larger, and there was also a trend towards increased proportion of proteoglycans aggregating with hyaluronan. Most of the chondroitin sulfate side chains were 6-sulfated (65-66%). Running did not alter the sulfation or length of the chondroitin sulfate chains. The decreased proteoglycan/collagen ratio in annulus fibrosus may result in altered mechanical properties of the tissue and reflects its adaptation to enhanced motion and stress.

Animals↗
PubMed1992

Articular cartilage thickness and glycosaminoglycan distribution in the canine knee joint after strenuous running exercise.

The influences of the strenuous running training program on the knee joint articular cartilage was studied in six female beagle dogs. At the age of 15 weeks, the dogs started running on a treadmill inclined 15 degrees uphill. Thereafter, the dogs were trained for 40 weeks, five times a week. For the final 15 weeks, the dogs ran 20 km/day. Six age-matched female beagles served as controls. The cartilage surfaces were intact after the running exercise. The training reduced the thickness of the uncalcified cartilage by 6% in the medial femoral condyle. The glycosaminoglycan concentration was reduced an average of 11% on the summits of the femoral condyles. The reduction was most pronounced (41%) in the superficial 50-micron cartilage zone. In other regions of the knee, such a decrease of glycosaminoglycans was not observed. A shift to strenuous running voided the increase in cartilage thickness and proteoglycan content previously observed after moderate running. Strenuous running induced marked depletion of proteoglycans from the superficial layer of the femoral condyles at sites subjected to highest impact loads.

Animals↗
PubMed1991

A ten-track treadmill for running training of dogs.

A large treadmill was constructed to allow simultaneous running and training of 10 dogs. During a period of 1 year, 10 beagles ran up to 40 km/day at a speed of 5.5 to 6.8 km/h and with an uphill inclination of 15 degrees. By the end of training, the daily running sessions lasted 7 hours. The design of the treadmill and experience of the treadmill training is given. The apparatus was reliable and convenient to use.

Animals↗
PubMed1990

Proteoglycan alterations following immobilization and remobilization in the articular cartilage of young canine knee (stifle) joint.

The distribution of proteoglycans (PGs) at 11 sites on the knee (stifle joint) cartilage of young female beagle dogs was studied following cast immobilization for 11 weeks in 90 degrees flexion and after a subsequent remobilization for 15 weeks. Immobilization induced a reduction in PG uronic acid at all sites (mean of -38%), but the greatest depletion (-64%) occurred at the anterior and posterior extremes of the femoral condyles, i.e., at locations where the immobilized cartilage lost contact to the opposing cartilage. Following remobilization, the content of uronic acid remained lower than in the age-matched controls (-18% on average), particularly at the minimum contact sites most affected by immobilization (-33%). The chondroitin-6-sulfate to chondroitin-4-sulfate ratio was reduced by immobilization in most locations (average of -14%) and returned to control values after remobilization. There was no consistent change in the percentage of aggregating PGs observed in Sephacryl S-1000 gel filtration after immobilization or remobilization. However, following remobilization, the aggregating PGs showed an enhanced proportion of the slower mobility band in agarose gel electrophoresis, indicative of a larger monomer size. In the contralateral, load-bearing knee joint, both the uronic acid content and PG monomer type distribution were identical to those observed in the experimental joint, suggesting that the state reached after the remobilization period was due to factor(s) influencing both sides. The results suggest that contact forces between articulating surfaces are required to maintain normal PG content and that the control mechanism works locally at each cartilage site. Restriction of joint mobility and loading in young animals is concluded to cause persistent changes in cartilage matrix. Furthermore, the use of the contralateral joint as the sole control in this kind of studies, although experimentally convenient, seems not to be appropriate.

Animals↗
PubMed1990

Indentation stiffness of young canine knee articular cartilage--influence of strenuous joint loading.

The indentation stiffness of knee articular cartilage subjected to strenuous physical training (SPT: treadmill running 20 km day-1 for 15 weeks, n = 6) of young Beagles was tested and compared to that obtained from age-matched (55 weeks, n = 9) controls. The mathematical solution for the shear modulus, as determined from indentation of an elastic layer bonded to a rigid half space, was extended to small Poisson's ratios and applied to the analysis of cartilage response after a step stress (0.39 MPa) application. In these measurements with an impervious, plane-ended indenter, the equilibrium deformation was systematically greater than values predicted from the instant response by the linear biphasic theory. Therefore, the accurate determination of Poisson's ratio from the creep curves was not possible. The mean shear modulus (calculated by using the deformation at 900 s after load application and assuming a constant Poisson's ratio of 0.40 for the matrix) of canine knee articular cartilage was 0.37 MPa. While the cartilage thickness was not affected by SPT, the cartilage of the lateral tibial plateau was stiffer (13.3%, p less than 0.05) than that in controls. However, in the femoral condyles, the stiffness was at the control level or even below. Our results on cartilage structure and properties suggest that SPT, in contrast to our previous findings with moderate training, does not necessarily improve the biological properties of articular cartilage in young animals.

Animals↗
PubMed1989

Levels of chondroitin-6-sulfate and nonaggregating proteoglycans at articular cartilage contact sites in the knees of young dogs subjected to moderate running exercise.

The levels and types of proteoglycans in articular cartilage of the knees of young beagle dogs were studied after 15 weeks of running exercise, at 4 km/day. Running increased the levels of proteoglycans in the cartilage of the patella, the superior patellofemoral groove, and the summit of the medial condyle of the femur, all of which are considered contact sites subject to enhanced loading caused by running. The elevated content of uronic acid at the femoral sites proved to be due to proteoglycans that were unable to aggregate with hyaluronic acid. There was no change in the content of aggregating proteoglycans. Analysis of chondroitinase AC-derived disaccharides at the same sites showed an increase in chondroitin-6-sulfate content as compared with chondroitin-4-sulfate levels. We believe that this modulation of the proteoglycan matrix reflects enhanced tissue maturation and physiologic adjustment to higher local contact pressures.

Animals↗
PubMed1989

Partial restoration of immobilization-induced softening of canine articular cartilage after remobilization of the knee (stifle) joint.

The restoration of the biomechanical properties of articular cartilage was studied after 15 weeks of remobilization of the knee joint in beagles previously immobilized with a cast for 11 weeks. The shear moduli were determined with an indentation creep test immediately after load application and at equilibrium at six predefined test points of femoral, tibial, and patellar cartilages. Permeability of the cartilage was estimated from the creep measurements. The values were compared with nontreated, age-matched (55 weeks) controls and with cartilage collected immediately after immobilization. Remobilization reduced the high creep rates created by immobilization and shifted the depressed equilibrium shear moduli towards those of the controls. However, in the femoral condylar cartilage, the equilibrium shear modulus remained at lower level (p less than 0.05) and permeability at higher level (p less than 0.05) as compared with the controls. We conclude that articular cartilage, showing signs of atrophy after long-term immobilization, was capable of restoring its biomechanical properties during remobilization. This repair was not, however, completed in all parts of the knee joint by the end of the observation period.

Animals↗
PubMed1988

Moderate running exercise augments glycosaminoglycans and thickness of articular cartilage in the knee joint of young beagle dogs.

The local influences of physical exercise on thickness and glycosaminoglycan (GAG) content of canine articular cartilage were measured by microspectrophotometry of Safranin O- and periodic acid-Schiff (PAS)-stained tissue sections. Female Beagle dogs were housed in individual cages (bottom 0.9 x 1.2 m) and divided into runner (n = 6) and control (n = 8) groups. The training program started at the age of 15 weeks. During the subsequent 10 weeks, the dogs were accustomed to running on a treadmill inclined 15 degrees uphill. Thereafter, the dogs ran 1 h daily, 5 days a week, at a speed of 4 km/h for 15 weeks. At the age of 40 weeks, the dogs were killed, and the samples for histology were taken from 11 different anatomical locations of the right knee (stifle) joint. The thickness of the uncalcified cartilage increased 19-23% on the lateral condyle and patellar surface of the femur, whereas the enhancement was smaller in other parts of the trained cartilage. The calcified cartilage did not show thickness alterations. Total GAGs were augmented by 28% in the summits on the femoral condyles, more on the medial than lateral side. The increased GAGs appeared to be predominantly chondroitin sulphates and were localized in the intermediate, deep, and even in the calcified zones, whereas the superficial zone did not show changes. There was a concomitant increase of non-GAG oligosaccharides in the intermediate and deep zones, but not in the calcified cartilage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗