Showing papers by "Jukka S. Jurvelin published in 1994"

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.

Abstract: 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.

Proteoglycan and Collagen Alterations in Canine Knee Articular Cartilage Following 20 KM Daily Running Exercise for 15 Weeks

Abstract: 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 strenu...

Samarium-153-EDTMP in bone metastases.

Abstract: Thirty-five patients with painful bone metastases arising from a variety of tumor types underwent a clinical trial in which 153Sm-EDTMP was injected as a single intravenous dose The injection ranged in amount from 330 MBq to 1110 MBq of 153Sm-EDTMP Pain relief usually occurred within one week after administration The duration of pain relief lasted from 2 to 17 weeks A detectable degree of pain palliation was experienced by 80% of the treated patients; 54% reported substantial or complete pain relief Due to the small number of patients, no clear-cut dose-related response was detectable Moderate myelosuppression was observed in one patient (WHO grade III) The metastatic lesion-to-normal bone ratios remained constant (varying from 15 to 48) for at least 5 days post-injection 153Sm cleared very rapidly from the blood Less than 1% of the injected dose remained in circulation at 4 hours post-injection No local accumulation of the tracer could be detected outside the skeleton Urinary excretion was quite complete at 6 hours post-injection The biodistributions of 153Sm-EDTMP and 99mTc-DPD are very similar in metastatic and normal bone; thus, bone scanning can be used for patient selection and followup According to our results, it seems that higher doses of 153Sm-EDTMP can be given safely and without any irreversible myelosuppression

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

Abstract: 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.

A Finnish multicentre quality assurance project in bone scintigraphy and brain SPET: a phantom study.

Abstract: We examined all routinely used bone scintigraphy and brain single photon emission tomographic (SPET) systems in 19 laboratories in Finland. Physical performance of bone scintigraphy systems was measured with a 57Co flood source and with a NEMA resolution phantom. Total performance of the systems was evaluated with a transmission phantom simulating bone imaging of the thorax. It was acquired both with the protocol used in a given laboratory and with a fixed protocol. The participant laboratories were asked to report all accumulations on a diagrammatic thorax drawing. Tomographic uniformity, contrast and resolution (i.e. physical performance) of the SPET systems were evaluated with a special phantom. In addition, a Hoffman brain phantom was measured with routinely used acquiring and reconstruction protocols (total performance). All measurements were performed with the same test objects supervised by the same physicist. Manufacturer, age or the collimator of the camera did not correlate with the physical performance of the imaging systems (r < 0.65). This is probably due to lack of regular quality control of the gamma cameras in some laboratories. Comparison of the physical and the total performance shows that the detector itself is not necessarily responsible for inaccurate findings from the test object. Use of dual intensity and digital images in both scintigraphy could certainly increase the sensitivity of the findings: sensitivity of single intensity images was 65% (33-89%), dual 73% (28-100%), analog 65% (28-100%) and digital 74% (50-94%). Standardization of acquisition and reconstruction protocols will improve quality of brain SPET images and comparability between laboratories. This study showed the need for objective audit tests of bone scintigraphy and brain SPET systems in Finland.