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Sökning: WFRF:(Helminen Heikki)

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1.
  • Arokoski, Jari, et al. (författare)
  • Nivelrikon etiopatogeneesi [Etiopathogenesis of osteoarthritis].
  • 2001
  • Ingår i: Duodecim. - : Duodecim. - 0012-7183 .- 2242-3281. ; 117:16, s. 1617-1626
  • Tidskriftsartikel (refereegranskat)abstract
    • Nivelrikon patofysiologia tunnetaan huonosti. Nykykäsityksen mukaan artroosissa ei olekyse nivelruston passiivisesta kulumisesta vaan biokemiallisesta tapahtumasarjasta, jossasoluväliaineen tuhoutuminen saa ylivallan rustoa korjaavista prosesseista. Nivelrikon alkuvaiheessarustosoluissa eli kondrosyyteissä aktivoituvat sekä ruston aineosien synteesitoimintaettä rustoa hajottavien entsyymien ilmentyminen ja niitä koodaavien geenientoiminta. Nivelrikko on koko nivelen sairaus, joka aiheuttaa muutoksia niin nivelrustossa,luussa kuin pehmytosissakin. Vallitsevan käsityksen mukaan nivelrikko käynnistyynivelruston pinnallisesta vyöhykkeestä. On myös esitetty, että nivelalueen altistuminenliialliselle kuormitukselle aiheuttaisi ensin rustonalaisen luun paksunemisen ja jäykkenemisen,mikä puolestaan altistaisi nivelruston suuremmille kuormittaville voimille. Riskitekijöistätärkeimpiä ovat ikääntyminen, liikapaino, niveleen kohdistuvat vammat ja ruumiillisentyön aiheuttama liikarasitus. Perinnöllisten tekijöiden osuus on myös merkittävä.Ruston kollageenien rakennevirheiden tiedetään altistavan nivelrikolle.
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2.
  • Elo, Mika, et al. (författare)
  • Differential regulation of stress proteins by high hydrostatic pressure, heat shock, and unbalanced calcium homeostasis in chondrocytic cells.
  • 2000
  • Ingår i: Journal of Cellular Biochemistry. - : John Wiley & Sons. - 0730-2312 .- 1097-4644. ; 79:4, s. 610-619
  • Tidskriftsartikel (refereegranskat)abstract
    • High hydrostatic pressure (HP) has recently been shown to increase cellular heat shock protein 70 (Hsp70) level in a specific way that does not involve transcriptional activation of the gene, but rather the stabilisation of the mRNA for Hsp70. In this study, we investigated whether there are other observable changes caused by HP stress, and compared them with those induced by certain other forms of stressors. A chondrocytic cell line T/C28a4 was exposed to 30 MPa continuous HP, heat shock at 43 degrees C, and increased cytosolic calcium concentration by the addition of sarco-endoplasmic reticulum Ca(2+) ATPase inhibitor thapsigargin (25 nM) or calcium ionophore A23187 (1 microM) in the cultures. The protein synthesis was studied by in vitro metabolic labelling followed by one- and two-dimensional polyacrylamide gel electrophoresis, and mass spectrometry was utilized to confirm the identity of the protein spots on two-dimensional gels. Continuous 30 MPa HP increased remarkably the relative labelling of Hsp70. Labelling of Hsp90 was also increased by 15-20%, although no clear change was evident at the protein level in Western blots. Elevated intracellular Ca(2+) concentration induced by thapsigargin and calcium ionophore A23187 increased mainly the synthesis of glucose-regulated protein 78 (Grp78/BiP), whereas Hsp70 and Hsp90 were decreased by the treatment. Heat shock was the strongest inducer of Hsp70 and Hsp90. This study further confirmed the induction of Hsp70 in chondrocytic cells exposed to high HP, but it also showed that calcium-mediated responses are unlikely to cause the stress response observed in the hydrostatically pressurized cells.
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3.
  • Elo, Mika, et al. (författare)
  • High hydrostatic pressure inhibits the biosynthesis of eukaryotic elongation factor-2.
  • 2005
  • Ingår i: Journal of Cellular Biochemistry. - : John Wiley & Sons. - 0730-2312 .- 1097-4644. ; 94:3, s. 497-507
  • Tidskriftsartikel (refereegranskat)abstract
    • High continuous hydrostatic pressure is known to inhibit the total cellular protein synthesis. In this study, our goal was to identify pressure-regulated proteins by using two dimensional gel electrophoresis and mass spectrometry. This analysis showed that under 30 MPa continuous hydrostatic pressure the biosynthesis of eukaryotic elongation factor-2 (eEF-2) was inhibited both in HeLa carcinoma and T/C28a4 chondrocytic cell lines. Western blot analysis of HeLa cells revealed that the cellular protein level of eEF-2 decreased by 40%-50% within 12 h of the pressure treatment. However, the steady-state mRNA level of eEF-2 was not affected by the pressure. Cycloheximide addition after 4 h-pressure treatment suggested that the half-life of eEF-2 protein was shorter in pressurized cells. eEF-2 is responsible for the translocation of ribosome along the specific mRNA during translation, and its phosphorylation prevents the ribosomal translocation. Therefore, increased phosphorylation of eEF-2 was considered as one mechanism that could explain the reduced level of protein synthesis in pressurized HeLa cell cultures. However, Western blot analysis with an antibody recognizing the Thr56-phosphorylated form of eEF-2 showed that phosphorylation of eEF-2 was not elevated in pressurized samples. In conclusion, the inhibition of protein synthesis under high pressure occurs independent of the phosphorylation of eEF-2. However, this inhibition may result from the decrease of cellular eEF-2 protein.
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4.
  • Elo, Mika, et al. (författare)
  • Hsp90 inhibitor geldanamycin increases hsp70 mRNA stabilisation but fails to activate HSF1 in cells exposed to hydrostatic pressure.
  • 2005
  • Ingår i: Biochimica et Biophysica Acta. - : Elsevier. - 0006-3002 .- 1878-2434. ; 1743:1-2, s. 115-119
  • Tidskriftsartikel (refereegranskat)abstract
    • High hydrostatic pressure (HP) increases Hsp70 protein and mRNA levels by increasing the mRNA half-life without activation of HSF1 transcription factor. We investigated whether this change in gene expression requires Hsp90, previously shown to regulate hsp70 genes via HSF1. In HeLa cells, both HP and Hsp90 inhibitor geldanamycin (GA) up-regulated Hsp70 expression through mRNA stabilisation. GA, unlike HP, increased HSF1 activation. However, when exposures were used together a marked Hsp70 response was observed with mRNA stabilisation without coincidence of HSF1 activation. Our data suggests that Hsp90 is involved in hsp70 mRNA stabilisation and the HSF1 activation can be suppressed by high HP.
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5.
  • Elo, Mika, et al. (författare)
  • Specific induction of heat shock protein 90beta by high hydrostatic pressure.
  • 2003
  • Ingår i: Biorheology. - : IOS Press. - 0006-355X .- 1878-5034. ; 40:1-3, s. 141-146
  • Tidskriftsartikel (refereegranskat)abstract
    • In chondrocytes, a low-amplitude intermittent hydrostatic pressure induces production of extracellular matrix molecules, while high hydrostatic pressure inhibits it. High pressure increases cellular heat shock protein 70 level in a number of cell types on account of increased stabilisation of the heat shock protein 70 mRNA. In our experiments, only bovine primary chondrocytes, but not an immortalized chondrocytic cell line, could resist the induction of the stress response in the presence of continuous 30 MPa hydrostatic pressure. We have recently shown that protein synthesis is required for the stabilization. According to two-dimensional gel electrophoresis the synthesis of heat shock protein 90 was also increased in a chondrocytic cell line and in HeLa cells, and mass spectrometric analysis suggested that the induction was rather due to increase in heat shock protein 90beta than in heat shock protein 90alpha. The stress response was rather intense in HeLa cells, therefore, we investigated the effect of continuous 30 MPa hydrostatic pressure on the expression of the two heat shock protein 90 genes in HeLa cells using Northern and Western blot analyses. Heat shock protein 90beta mRNA level increased within 6 hours of exposure to 30 MPa hydrostatic pressure, while hsp90alpha level remained stable. At protein level there was a clear increase in the heat shock protein 90beta/heat shock protein 90alpha ratio, too. These results show a specific regulation of stress proteins in cells exposed to high hydrostatic pressure.
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6.
  • Espanha, Maria, et al. (författare)
  • Extracellular matrix composition of full-thickness defect repair tissue is little influenced by exercise in rat articular cartilage.
  • 2001
  • Ingår i: Connective Tissue Research. - 0300-8207 .- 1607-8438. ; 42:2, s. 97-109
  • Tidskriftsartikel (refereegranskat)abstract
    • Full-thickness articular cartilage defects in the femoral condyles of adult rats were examined four and eight weeks after injury. Quantitative polarized light microscopic analysis showed that birefringence of the tissue in the central repair area increased more in rats exercised on a treadmill. Glycosaminoglycan content in the repair tissue was also higher than in the intermittent active motion group at four weeks after injury, but by eight weeks the levels were similar in both groups. No normal-looking articular cartilage was formed in the lesions, and only in one animal type II collagen was observed in the superficial zone of repair tissue. No 3B3(-) antigenicity of the proteoglycans was seen during repair. In conclusion, exercise minimally modified the repair of full-thickness articular cartilage defects in adult rats. The repair in the exercised group may occur slightly faster in the early stages but no difference was seen at the eight week time interval between the exercised and the intermittently active group.
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7.
  • Haapala, Jussi, et al. (författare)
  • Coordinated regulation of hyaluronan and aggrecan content in the articular cartilage of immobilized and exercised dogs.
  • 1996
  • Ingår i: Journal of Rheumatology. - : Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 23:9, s. 1586-1593
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To study the influence of joint loading and immobilization on articular cartilage hyaluronan concentration and histological distribution in the knee joints of young dogs subjected to 11 weeks' immobilization by splinting, and 15 weeks' running exercise at a rate of 40 km/day.METHODS: The amount of hyaluronan in articular cartilage was determined by a competitive binding assay using a biotinylated hyaluronan binding complex (HABC) of aggrecan and link protein. Histologic sections were stained for the localization of hyaluronan with the HABC probe. Extracted proteoglycans were characterized by sodium dodecyl sulfate agarose gel electrophoresis.RESULTS: Immobilization significantly reduced the concentration of hyaluronan in all sites studied (tibial and femoral condyles, patellar surface of femur). The proportion of hyaluronan to total uronic acid (mainly from aggrecan) remained unchanged because of a concurrent decrease in aggrecan. The ratio of hyaluronan and aggrecan remained constant also in runners. The staining pattern of free hyaluronan in the tissue sections and the electrophoretic mobility of the extracted proteoglycans were not affected by the different loading regimes.CONCLUSION: Reduced joint loading due to splint immobilization significantly decreases both hyaluronan and aggrecan in the articular cartilage. The remarkably parallel changes in aggrecan and hyaluronan content suggest that joint loading exerts a coordinated influence on their metabolism.
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8.
  • Haapala, Jussi, et al. (författare)
  • Remobilization does not fully restore immobilization induced articular cartilage atrophy.
  • 1999
  • Ingår i: Clinical Orthopaedics and Related Research. - : Lippincott Williams & Wilkins. - 0009-921X .- 1528-1132. ; :362, s. 218-229
  • Tidskriftsartikel (refereegranskat)abstract
    • The recovery of articular cartilage from immobilization induced atrophy was studied. The right hind limbs of 29-week-old beagle dogs were immobilized for 11 weeks and then remobilized for 50 weeks. Cartilage from the immobilized knee was compared with tissue from age matched control animals. After the immobilization period, uncalcified articular cartilage glycosaminoglycan concentration was reduced by 20% to 23%, the reduction being largest (44%) in the superficial zone. The collagen fibril network showed no significant changes, but the amount of collagen crosslinks was reduced (13.5%) during immobilization. After remobilization, glycosaminoglycan concentration was restored at most sites, except for in the upper parts of uncalcified cartilage in the medial femoral and tibial condyles (9% to 17% less glycosaminoglycans than in controls). The incorporation of 35SO4 was not changed, and remobilization also did not alter the birefringence of collagen fibrils. Remobilization restored the proportion of collagen crosslinks to the control level. The changes induced by joint unloading were reversible at most sites investigated, but full restoration of articular cartilage glycosaminoglycan concentration was not obtained in all sites, even after remobilization for 50 weeks. This suggests that lengthy immobilization of a joint can cause long lasting articular cartilage proteoglycan alterations at the same time as collagen organization remains largely unchanged. Because proteoglycans exert strong influence on the biomechanical properties of cartilage, lengthy immobilization may jeopardize the well being of articular cartilage.
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9.
  • Helminen, Heikki, et al. (författare)
  • Kuormituksen vaikutus nivelrustoon [The effects of loading on articular cartilage].
  • 1992
  • Ingår i: Duodecim. - : Duodecim. - 0012-7183 .- 2242-3281. ; 108:12, s. 1097-1107
  • Forskningsöversikt (refereegranskat)abstract
    • Nivelen kuormitus on tärkeimpiä nivelruston aineenvaihduntaan ja rakenteeseen vaikuttavia fysiologisia tekijöitä. Kohtuullinen rytminen kuormitus lisää nuoren ihmisen nivelruston proteoglykaanipitoisuutta. Tämän vaikutuksesta rusto jäykistyy ja kasvaa paksuutta. Hyvin voimakas kuormitus ei aiheuta tällaista positiivista vastetta. Toisaalta nivelkuormituksen puuttuminen pienentää ruston proteoglykaanipitoisuutta ja heikentää kimmo-ominaisuuksia. Nämä surkastumismuutokset ovat suurimmaksi osaksi–elleivät kokonaan–korjautuvia. Kohtuullisella nivelkuormituksella voidaan siis ylläpitää ja parantaa nivelruston ominaisuuksia. Pitkäaikaisen liikkumattomuuden jälkeen nivelrusto on heikompi kuin normaalisti ja voi vaurioitua niveltä voimakkaasti kuormitettaessa. Siksi nivelen kuormitusta pitää lisätä toipumisvaiheessa vähitellen.
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10.
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11.
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12.
  • Hyttinen, Mika, et al. (författare)
  • Age matters : collagen birefringence of superficial articular cartilage is increased in young guinea-pigs but decreased in older animals after identical physiological type of joint loading.
  • 2001
  • Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 9:8, s. 694-701
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To compare responses of the collagen network and glycosaminoglycans (GAGs) of articular cartilage to physiological type of joint loading in young growing and adult mature guinea-pigs.DESIGN: 10- and 44-week-old guinea-pigs were accustomed to treadmill running for 3 weeks. Thereafter the animals ran 2500 m/day, 5 days a week, for 15 weeks. Articular cartilage specimens from knee joints were collected at 28 and 62 weeks. Osteoarthritis (OA) prevalence and severity was evaluated by aid of light microscopy. The degree of collagen fibril network organization and content was analyzed with quantitative polarized light microscopy. The local concentration of GAGs was determined from cartilage sections with digital densitometry after safranin-O staining.RESULTS: In the young guinea-pigs, running increased up to 24% the optical retardation of polarized light by collagen in the superficial articular cartilage of femur, indicating either a higher degree of fibril assembly and organization or increased amount of collagen, or both. In contrast, in the adult mature animals the optical retardation decreased almost 50% after joint loading (P< 0.01-0.001). Running did not increase cartilage fibrillation. Significant changes in GAG content of cartilage were not found either in the young or adult mature runners.CONCLUSIONS: Increased birefringence of the superficial articular cartilage after joint loading in young guinea-pigs can be interpreted to be a sign of improved and decreased birefringence in older animals a sign of worsened property of the collagen network. It can be suggested therefore that joint loading strengthened the collagen network in the young runners. It can be hypothesized further that with time the inferior property of the collagen network predisposes the older runners to earlier OA than in controls.
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13.
  • Jortikka, Matti, et al. (författare)
  • Immobilisation causes longlasting matrix changes both in the immobilised and contralateral joint cartilage.
  • 1997
  • Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 56:4, s. 255-261
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: The capacity of articular cartilage matrix to recover during 50 weeks of remobilisation after an atrophy caused by 11 weeks of immobilisation of the knee (stifle) joint in 90 degrees flexion starting at the age of 29 weeks, was studied in young beagle dogs.METHODS: Proteoglycan concentration (uronic acid) and synthesis ([35S]sulphate incorporation) were determined in six and three knee joint surface locations, respectively. Proteoglycans extracted from the cartilages were characterised by chemical determinations, gel filtration, and western blotting for chondroitin sulphate epitope 3B3.RESULTS: The proteoglycan concentrations that were reduced in all sample sites immediately after the immobilisation, remained 14-28% lower than controls after 50 weeks of remobilisation in the patella, the summit of medial femoral condyle, and the superior femoropatellar surface. In the contralateral joint, there was a 49% increase of proteoglycans in the inferior femoropatellar surface after remobilisation, while a 34% decrease was simultaneously noticed on the summit of the medial femoral condyle. Total proteoglycan synthesis was not significantly changed after immobilisation or 50 weeks' remobilisation in the treated or contralateral joint, compared with age matched controls. The chondroitin 6- to 4- sulphate ratio was reduced by immobilisation both in the radioactively labelled and the total tissue proteoglycans. In the remobilised joint, this ratio was restored in femur, while in tibia it remained at a level lower than controls. Neither immobilisation nor remobilisation induced epitopes recognised by the monoclonal antibody 3B3 on native (undigested) proteoglycans.CONCLUSION: These results show that the depletion of proteoglycans observed after 11 weeks of immobilisation was not completely restored in certain surface sites after 50 weeks of remobilisation. The significant changes that developed in the contralateral joint during the remobilisation period give further support to the idea that a permanent alteration of matrix metabolism results even from a temporary modification of loading pattern in immature joints.
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14.
  • Julkunen, Petro, et al. (författare)
  • Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage.
  • 2009
  • Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 17:12, s. 1628-1638
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: The structure and composition of articular cartilage change during development and growth. These changes lead to alterations in the mechanical properties of cartilage. In the present study, biomechanical, biochemical and structural relationships of articular cartilage during growth and maturation of rabbits are investigated.DESIGN: Articular cartilage specimens from the tibial medial plateaus and femoral medial condyles of female New Zealand white rabbits were collected from seven age-groups; 0 days (n=29), 11 days (n=30), 4 weeks (n=30), 6 weeks (n=30), 3 months (n=24), 6 months (n=24) and 18 months (n=19). The samples underwent mechanical testing under creep indentation. From the mechanical response, instantaneous and equilibrium moduli were determined. Biochemical analyses of tissue collagen, hydroxylysylpyridinoline (HP) and pentosidine (PEN) cross-links in full thickness cartilage samples were conducted. Proteoglycans were investigated depth-wise from the tissue sections by measuring the optical density of Safranin-O-stained samples. Furthermore, depth-wise collagen architecture of articular cartilage was analyzed with polarized light microscopy. Finite element analyses of the samples from different age-groups were conducted to reveal tensile and compressive properties of the fibril network and the matrix of articular cartilage, respectively.RESULTS: Tissue thickness decreased from approximately 3 to approximately 0.5mm until the age of 3 months, while the instantaneous modulus increased with age prior to peak at 4-6 weeks. A lower equilibrium modulus was observed before 3-month-age, after which the equilibrium modulus continued to increase. Collagen fibril orientation angle and parallelism index were inversely related to the instantaneous modulus, tensile fibril modulus and tissue thickness. Collagen content and cross-linking were positively related to the equilibrium compressive properties of the tissue.CONCLUSIONS: During maturation, significant modulation of tissue structure, composition and mechanical properties takes place. Importantly, the present study provides insight into the mechanical, chemical and structural interactions that lead to functional properties of mature articular cartilage.
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15.
  • Kaarniranta, Kai, et al. (författare)
  • A mouse model for Stickler's syndrome; ocular phenotype of mice carrying a targeted heterozygous inactivation of type II (pro)collagen gene (Col2a1).
  • 2006
  • Ingår i: Experimental Eye Research. - : Elsevier. - 0014-4835 .- 1096-0007. ; 83:2, s. 297-303
  • Tidskriftsartikel (refereegranskat)abstract
    • The influences of targeted heterozygous inactivation of type II (pro)collagen gene (Col2a1) on eye structures in the 15-month-old C57BL/6JOlaHsd mouse was studied. The eyes were collected from C57BL mice heterozygous for a targeted inactivation of one allele of the Col2a1 gene (Col2a1(+/-) mice). The eyes of C57BL mice with normal gene alleles were used as controls (Col2a1(+/+) mice). Ocular histology was analyzed from tissue sections, stained with hematoxylin and eosin, toluidine blue and alcian blue. Type II collagen was localized by immunohistochemistry. Hyaluronan (HA) was stained utilizing the biotinylated complex of the hyaluronan-binding region of aggrecan and link protein (bHABC). The anterior segment of the eye was well-formed in both genotypes, but typical folding of ciliary processes was decreased, while increased stromal extracellular matrix vacuolization was seen in the Col2a1(+/-) mice. In the lens of these mice, subcapsular extracellular matrix changes were observed. Differences in retinal structures or the number of the eyes with retinal detachment were not detected between the genotypes. In Col2a1(+/-) mice, staining for type II collagen was weaker in cornea, ciliary body, iris, lens, vitreous, retina, choroid and sclera than in the control mice. HA staining was detected in the extraocular tissues, ciliary body, iris and the choroid of both genotypes. HA staining was observed only in the vitreous body of the control animals. Heterozygous inactivation of Col2a1 gene causes structural defects in the murine eye. The observed structural changes in the ciliary body, lens and vitreous of the Col2a1(+/-) mice may represent ocular features found in the human Stickler syndrome, where the abnormalities result from COL2A1 gene mutations which lead to functional haploinsufficiency.
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16.
  • Kaarniranta, Kai, et al. (författare)
  • Hsp70 accumulation in chondrocytic cells exposed to high continuous hydrostatic pressure coincides with mRNA stabilization rather than transcriptional activation.
  • 1998
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 95:5, s. 2319-2324
  • Tidskriftsartikel (refereegranskat)abstract
    • In response to various stress stimuli, heat shock genes are induced to express heat shock proteins (Hsps). Previous studies have revealed that expression of heat shock genes is regulated both at transcriptional and posttranscriptional level, and the rapid transcriptional induction of heat shock genes involves activation of the specific transcription factor, heat shock factor 1 (HSF1). Furthermore, the transcriptional induction can vary in intensity and kinetics in a signal- and cell-type-dependent manner. In this study, we demonstrate that mechanical loading in the form of hydrostatic pressure increases heat shock gene expression in human chondrocyte-like cells. The response to continuous high hydrostatic pressure was characterized by elevated mRNA and protein levels of Hsp70, without activation of HSF1 and transcriptional induction of hsp70 gene. The increased expression of Hsp70 was mediated through stabilization of hsp70 mRNA molecules. Interestingly, in contrast to static pressurization, cyclic hydrostatic loading did not result in the induction of heat shock genes. Our findings show that hsp70 gene expression is regulated posttranscriptionally without transcriptional induction in chondrocyte-like cells upon exposure to high continuous hydrostatic pressure. We suggest that the posttranscriptional regulation in the form of hsp70 mRNA stabilization provides an additional mode of heat shock gene regulation that is likely to be of significant importance in certain forms of stress.
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17.
  • Kaarniranta, Kai, et al. (författare)
  • Neuronal cells show regulatory differences in the hsp70 gene response.
  • 2002
  • Ingår i: Brain Research. Molecular Brain Research. - : Elsevier. - 0169-328X .- 1872-6941. ; 101:1-2, s. 136-140
  • Tidskriftsartikel (refereegranskat)abstract
    • The synthesis of heat shock proteins (Hsps), encoded by heat shock genes, is increased in response to various stress stimuli. Hsps function as molecular chaperones, they dissociate cytotoxic stress-induced protein aggregates within cells and ensure improved survival. Induction of heat shock genes is mainly regulated at the transcriptional level. The stress responsive transcription factor, heat shock factor 1 (HSF1), is involved in the transcriptional induction of the heat shock genes. Our objective was to examine how hsp70 genes are regulated in different transformed and primary neurons upon exposure to elevated temperature. Our findings reveal that the Hsp70 response is regulated at the translational level in Neuro-2a neuroblastoma cells, while the IMR-32 neuroblastoma cells respond to stress by the classical HSF1-driven transcriptional regulatory mechanism. Primary rat hippocampal neurons show a lack of HSF1 and induction of the hsp70 gene. These observations suggest that neuronal cells display different hsp70 gene expression patterns which range from undetected response to transcriptional and posttranscriptional regulation during heat stress.
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18.
  • Kaarniranta, Kai, et al. (författare)
  • Primary chondrocytes resist hydrostatic pressure-induced stress while primary synovial cells and fibroblasts show modified Hsp70 response.
  • 2001
  • Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 9:1, s. 7-13
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: During joint loading, chondrocytes in the articular cartilage are subjected to gradients of high compressive hydrostatic pressure (HP). In response to diverse chemical or physical stresses, heat shock genes are induced to express heat shock proteins (Hsps). This study sought to examine the role of Hsps in baroresistance in primary bovine chondrocytes and synovial cells, as well as in primary human fibroblasts.METHODS: Northern blotting was used to analyze the steady-state levels of hsp70 mRNA in the primary cells exposed to HP or heat stress. Hsp70 protein accumulation was analyzed by Western blotting, and the DNA-binding activity was examined by gel mobility shift assay.RESULTS: Primary bovine chondrocytes which have been adapted to live under pressurized conditions showed negligible Hsp70 response upon HP loading, whereas primary bovine synovial cells and human fibroblasts accumulated hsp70 mRNA and protein when subjected to HP. The response was initiated without activation of the heat shock transcription factor 1. Interestingly, pre-conditioning of the barosensitive fibroblasts with HP or heat shock reduced the Hsp70 response, indicating induction of baroresistance.CONCLUSION: This study suggests that Hsp70 can play an important role in the early stages of adaptation of cells to HP. Thus, the Hsp70 gene expression upon HP loading may serve as one indicator of the chondrocytic phenotype of the cells. This can be of use in the treatment of cartilage lesions.
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19.
  • Kaarniranta, Kai, et al. (författare)
  • Protein synthesis is required for stabilization of hsp70 mRNA upon exposure to both hydrostatic pressurization and elevated temperature.
  • 2000
  • Ingår i: FEBS Letters. - : Elsevier. - 0014-5793 .- 1873-3468. ; 475:3, s. 283-286
  • Tidskriftsartikel (refereegranskat)abstract
    • We have recently described that in chondrocytic cells high hydrostatic pressure (HP) causes a heat shock response via mRNA stabilization without a transcriptional activation of the hsp70 gene. In this study, we investigated whether this exceptional regulatory mechanism occurs more generally in different types of cells. Indeed, hsp70 mRNA and protein accumulated in HeLa, HaCat and MG-63 cells under 30 MPa HP, without DNA-binding of heat shock transcription factor 1 (HSF1) to the heat shock element of the hsp70 gene or formation of nuclear HSF1 granules, revealing a lack of transcriptional activation. Moreover, we observed that protein synthesis is needed for mRNA stabilization. Thus, high HP offers a model to study the mechanisms of hsp70 mRNA stabilization without HSF1-mediated induction of the heat shock gene response.
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20.
  • Kaarniranta, Kai, et al. (författare)
  • Solustressin tutkimuksesta kliinisiin läpimurtoihin? [From research of cellular stress to various clinical break through innovations?]
  • 2001
  • Ingår i: Duodecim. - : Duodecim. - 0012-7183 .- 2242-3281. ; 117:22, s. 2266-2272
  • Forskningsöversikt (refereegranskat)abstract
    • Fysikaalisen tai kemiallisen stressin seurauksena useiden geenien aktiivisuus vähenee,kun taas lämpösokki- eli stressigeenien induktio lisääntyy. Stressigeenit koodaavat lämpösokkiproteiineja(Hsp), jotka toimivat soluissa kaperoneina, »avustajina», auttaensolujen proteiineja laskostumaan oikein translaatiossa, kalvon läpi kuljetuksessa tai esimerkiksikorkean lämpötilan aiheuttaman vaurion jälkeen. Viime vuosina lämpösokkiproteiinienkliininen merkitys useiden sairauksien patogeneesissä, diagnostiikassa ja ennusteenmäärittämisessä on alkanut selvitä. Merkittävimmät kliiniset löydökset liittyvätiskeemisiin prosesseihin, kuten sydän- ja aivoinfarkteihin, useisiin neoplasioihin ja ikääntymiseen.Tässä katsauksessa käsittelemme stressigeenien säätelyä, Hsp70-stressiproteiinienkliinisiä yhteyksiä ja niiden mahdollisia hoitosovelluksia iskeemisissä, neoplastisissaja degeneratiivisissa prosesseissa.
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21.
  • Kaarniranta, Kai, et al. (författare)
  • Stress responses of mammalian cells to high hydrostatic pressure.
  • 2003
  • Ingår i: Biorheology. - : IOS Press. - 0006-355X .- 1878-5034. ; 40:1-3, s. 87-92
  • Tidskriftsartikel (refereegranskat)abstract
    • High hydrostatic pressure causes stress response in many types of mammalian cells. We have previously shown that an accumulation of heat shock protein 70 (Hsp70) in a chondrocytic cell line occurred without an activation of the gene itself. Stabilization of the hsp70 mRNA was shown to be the reason for the Hsp70 stress response in the pressurized cells. Since accumulation of Hsp70 in pressurized cells indicated that high hydrostatic pressure induces a stress response without heat shock transcription factor activation, we decided to investigate the activation of two other stress-associated transcription factors, activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB). Induction of Hsp70 in immortalized and primary chondrocytes, murine Neuro-2a neuroblastoma and HeLa cervical carcinoma cell lines was investigated at both mRNA and protein levels. In immortalized chondrocytes and HeLa cells, hsp70 mRNA levels were clearly elevated after 6 hours of the onset of 30 MPa continuous hydrostatic pressure, while in primary chondrocytes and Neuro-2a cells (the cells known to be stress-sensitive) no induction was observed. Surprisingly, neither heat shock nor high hydrostatic pressure could induce the hsp70 mRNA in Neuro-2a cells, although an activation of heat shock transcription factor could be observed in heat-shocked cells. No activation of the AP-1 and NF-kappaB binding to their target DNA sequences could be shown in the immortalized chondrocytes.
  •  
22.
  • Karjalainen, Hannu, et al. (författare)
  • Gene expression profiles in chondrosarcoma cells subjected to cyclic stretching and hydrostatic pressure. A cDNA array study.
  • 2003
  • Ingår i: Biorheology. - : IOS Press. - 0006-355X .- 1878-5034. ; 40:1-3, s. 93-100
  • Tidskriftsartikel (refereegranskat)abstract
    • Mechanical forces have a profound effect on cartilage tissue and chondrocyte metabolism. Strenuous loading inhibits the cellular metabolism, while optimal level of loading at correct frequency raises an anabolic response in chondrocytes. In this study, we used Atlas Human Cancer cDNA array to investigate mRNA expression profiles in human chondrosarcoma cells stretched 8% for 6 hours at a frequency of 0.5 Hz. In addition, cultures were exposed to continuous and cyclic (0.5 Hz) 5 MPa hydrostatic pressure. Cyclic stretch had a more profound effect on the gene expression profiles than 5 MPa hydrostatic pressure. Several genes involved with the regulation of cell cycle were increased in stretched cells, as well as mRNAs for PDGF-B, glucose-1-phosphate uridylyltransferase, Tiam1, cdc37 homolog, Gem, integrin alpha6, and matrix metalloproteinase-3. Among down-regulated genes were plakoglobin, TGF-alpha, retinoic acid receptor-alpha and Wnt8b. A smaller number of changes was detected after pressure treatments. Plakoglobin was increased under cyclic and continuous 5 MPa hydrostatic pressure, while mitogen-activated protein kinase-9, proliferating cell nuclear antigen, Rad6, CD9 antigen, integrins alphaE and beta8, and vimentin were decreased. Cyclic and continuous pressurization induces a number of specific changes. In conclusion, a different set of genes were affected by three different types of mechanical stimuli applied on chondrosarcoma cells.
  •  
23.
  • Kauppila, Joonas H, et al. (författare)
  • Intratumoral lactate metabolism in Barrett’s esophagus and adenocarcinoma
  • 2017
  • Ingår i: Oncotarget. - Stockholm : Karolinska Institutet, Dept of Molecular Medicine and Surgery. - 1949-2553.
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Monocarboxylate transporters (MCTs) are cell membrane proteins which transport pyruvate, lactate and ketone bodies across the plasma membrane. MCTs are activated in various cancers, but their expression in esophageal adenocarcinoma is not known. The present study was conducted to elucidate the expression of MCTs in esophageal adenocarcinoma and its precursor lesions. Results: Cytoplasmic MCT1, MCT4 and MTCO1 expression linearly increased from normal epithelium to Barrett's mucosa to dysplasia and cancer. Low cytoplasmic MCT1 expression associated with high T-class (P < 0.01), positive lymph node metastases (P < 0.05), positive distant metastases (P < 0.01) and high tumor stage (P < 0.01). High cytoplasmic MCT4 expression correlated significantly with positive distant metastases (P < 0.05). Both low MCT1 and high MCT4 histoscore predicted survival in univariate analysis (P < 0.01). MCT4 histoscore predicted survival in multivariate analysis (P = 0.043; HR 1.8 95%CI 1.0–3.1). MTCO1 expression was not correlated to clinicopathological variables or survival. Materials and Methods: MCT1, MCT4 and mitochondrial cytochrome c oxidase (MTCO1) expression were determined with immunohistochemistry in esophageal specimens from 129 patients with columnar dysplasia or adenocarcinoma. Specimens including normal esophagus (n = 88), gastric (n = 67) or intestinal metaplasia (n = 51), low-grade (n = 42), high-grade dysplasia (n = 37) and esophageal adenocarcinoma (n = 99) were evaluated. Conclusions: Major increase in markers of tumor metabolism occurs during carcinogenesis and progression of esophageal adenocarcinoma. MCT1 and MCT4 are prognostic factors in esophageal adenocarcinoma.
  •  
24.
  • Kauppila, Joonas H, et al. (författare)
  • Tenascin-C and fibronectin in normal esophageal mucosa, Barrett's esophagus, dysplasia and adenocarcinoma
  • 2017
  • Ingår i: Oncotarget. - Stockholm : Karolinska Institutet, Dept of Molecular Medicine and Surgery. - 1949-2553.
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Tenascin-C and fibronectin are adhesive glycoproteins modulating the structure of the extracellular matrix and cellular functions. Their expression and function in esophageal adenocarcinoma is poorly known. The aim of this study was to evaluate the expression of tenascin-C and fibronectin in esophageal adenocarcinoma and its precursor stages. RESULTS: Stromal tenascin-C and fibronectin expression were found in all evaluated lesion types. Expression of both molecules increased from gastric metaplasia towards adenocarcinoma (p<0.05). In carcinomas, tenascin-C expression in the bulk was associated with T-stage (p=0.006), presence of lymph node (p=0.004) and distant organ metastases (p=0.007). Abundant tenascin-C expression associated with poor survival (p=0.034) in univariate analysis. Fibronectin expression associated to T-stage (p=0.030). Expression of tenascin-C or fibronectin in the tumor invasive front was not associated to clinicopathological variables or survival. No significant correlation with tumor/stroma percentage, cancer-associated fibroblasts or mean vascular density was observed with either tenascin-C or fibronectin. METHODS: Tenascin-C and fibronectin were stained immunohistochemically and assessed in esophageal specimens from patients with esophageal adenocarcinoma (n=90) or dysplasia (n=30). Structures and lesion were evaluated including normal esophagus (n=77), gastric (n=61) or intestinal (n=51) metaplasia without dysplasia, and low-grade (n=42) or high-grade (n=34) dysplasia, and esophageal adenocarcinoma (n=90). In carcinomas, both bulk and invasive front were separately evaluated. In addition, tumor/stroma percentage, cancer-associated fibroblasts and mean vascular density were evaluated. CONCLUSIONS: Tenascin-C and fibronectin are upregulated in esophageal adenocarcinoma when compared to Barrett's esophagus and dysplasia. Increased tenascin-C expression is associated with metastasis and poor prognosis in esophageal adenocarcinoma.
  •  
25.
  • Király, Kari, et al. (författare)
  • Safranin O reduces loss of glycosaminoglycans from bovine articular cartilage during histological specimen preparation.
  • 1996
  • Ingår i: The Histochemical Journal. - : Chapman & Hill. - 0018-2214 .- 1573-6865. ; 28:2, s. 99-107
  • Tidskriftsartikel (refereegranskat)abstract
    • The ability of Safranin O, added to fixation and decalcification solutions, to prevent the escape of glycosaminoglycans (GAGs) from small cartilage tissue blocks during histological processing of cartilage has been studied. GAGs in the fixatives and decalcifying solutions used and those remaining in the 1 mm3 cubes of cartilage were assayed biochemically. The quantity of GAGs remaining in the cartilage cubes were determined from Safranin O-stained sections using videomicroscopy or microspectrophotometry. A quantity (10.6%) of GAGs were lost during a conventional 4% buffered formaldehyde fixation (48 h) and a subsequent decalcification in 10% EDTA (12 days) at 4 degrees C. Roughly one-quarter of the total GAG loss occurred during the 48 h fixation, and three-quarters during the 12 days of decalcification. Inclusion of 4% formaldehyde in the decalcification fluid decreased the loss of GAGs to 6.2%. The presence of 0.5% Safranin O in the fixative reduced this loss to 3.4%. When 0.5% Safranin O was included in the fixative and 4% formaldehyde in the decalcification solution, Safranin O staining of the histological sections increased on average by 13.5%. After fixation in the presence of 0.5% Safranin O, there was no difference in the staining intensities when decalcification was carried out in the presence of either Safranin O or formaldehyde, or both. It took 24 h for Safranin O to penetrate into the deep zone of articular cartilage, warranting a fixation period of at least this long. In conclusion, the addition of Safranin O to the fixative and either Safranin O or formaldehyde in the following decalcification fluid, markedly reduces the loss of GAGs from small articular cartilage explants during histological processing. However, for immunohistochemical studies, Safranin O cannot be included in the processing solutions, because it may interfere.
  •  
26.
  • Kiviranta, Ilkka, et al. (författare)
  • Effects of mechanical loading and immobilization on the articular cartilage
  • 1997
  • Ingår i: Bailliere's Clinical Orthopaedics. - 1074-8814. ; 2:1, s. 109-122
  • Forskningsöversikt (refereegranskat)abstract
    • Articular cartilage provides nearly frictionless surfaces for joint movemants and reduces contact pressures, protecting the underlying suchondral bone from excess stress. The unique properties of articular cartilage are based on the interaction of the main components of the extracellular matrix: proteoglycans (PGs), collagen and interstitial fluid. Animal experiments and in vitro studies demonstrate that one of the most important regulators of the extracellular matrix metabolism is mechanical loading acting on the joints. Unloading and immobilization leads to PG depletion and softening of articular cartilage, increasing the risk of permanent cartilage degeneration. Moderate running exercise and increased weight bearing increases cartilage thickness, PG concentration and improves biomechanical properties of articular cartilage. With further increase in training intensity this positive influence of exercise disappears and cartilage shows changes analogous to immobilization of the joint, i.e. PG depletion and softening of the tissue. In humans most epidemiological studies  have failed to prove the connection between running training and cartilage degeneration, but there is evidence that sports activities exposing joints to impact loading might increase the risk of osteoarthrosis.
  •  
27.
  • Koistinen, Arto P, et al. (författare)
  • Short-term exercise-induced improvements in bone properties are for the most part not maintained during aging in hamsters.
  • 2014
  • Ingår i: Experimental Gerontology. - : Elsevier BV. - 1873-6815 .- 0531-5565. ; 51, s. 46-53
  • Tidskriftsartikel (refereegranskat)abstract
    • Physical exercise during growth affects composition, structure and mechanical properties of bone. In this study we investigated whether the beneficial effects of exercise during the early growth phase have long-lasting effects or not. Female Syrian golden hamsters (total n=152) were used in this study. Half of the hamsters had access to running wheels during their rapid growth phase (from 1 to 3months of age). The hamsters were sacrificed at the ages of 1, 3, 12, and 15months. The diaphysis of the mineralized humerus was analyzed with microCT and subjected to three-point-bending mechanical testing. The trabecular bone in the tibial metaphysis was also analyzed with microCT. The collagen matrix of the humerus bone was studied by tensile testing after decalcification. The weight of the hamsters as well as the length of the bone and the volumetric bone mineral density (BMDvol) of the humerus was higher in the running group at the early age (3months). Moreover, the mineralized bone showed improved mechanical properties in humerus and had greater trabecular thickness in the subchondral bone of tibia in the runners. However, by the age of 12 and 15months, these differences were equalized with the sedentary group. The tensile strength and Young's modulus of decalcified humerus were higher in the runners at early stage, indicating a stronger collagen network. In tibial metaphysis, trabecular thickness was significantly higher for the runners in the old age groups (12 and 15months). Our study demonstrates that physical exercise during growth improves either directly or indirectly through weight gain bone properties of the hamsters. However, the beneficial effects were for the most part not maintained during aging.
  •  
28.
  • Kopakkala-Tani, Milla, et al. (författare)
  • High hydrostatic pressure induces ERK and PI3 kinase phosphorylation in human HCS-2/8 chondrosarcoma cells.
  • 2004
  • Ingår i: Cellular and Molecular Biology. - 0145-5680 .- 1165-158X. ; 50:4, s. 485-490
  • Tidskriftsartikel (refereegranskat)abstract
    • High continuous hydrostatic pressure has been shown to affect many cellular functions within the pressurised cells, for instance, accumulation of heat shock protein 70 occurs during pressurisation. Various signal transduction pathways are likely to mediate these changes, however, at the present time our knowledge of the pathways involved is rather limited. The aim of this study was to investigate whether some of the well known transduction pathways are activated by the exposure of human chondrosarcoma cells to 15-30 MPa hydrostatic pressure. The results showed an increased presence of the active, phosphorylated forms of extracellular signal-related kinase (ERK) and phosphoinositide 3-kinase (PI3K) in cells exposed to 15 and 30 MPa continuous hydrostatic pressure, while 0.5 Hz cyclic loading had weaker effects. Inhibition of ERK-pathway with UO126 did not prevent the accumulation of heat shock protein 70. No activation of c-Jun N-terminal protein kinase (JNK) or p38 could be noticed in pressurised cells. In conclusion, we could identify at least two different signal transduction pathways that are activated under high continuous hydrostatic pressure. Accumulation of heat shock protein 70 was independent of ERK-activation.
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29.
  • Lammi, Mikko, 1961-, et al. (författare)
  • Adaptation of canine femoral head articular cartilage to long distance running exercise in young beagles.
  • 1993
  • Ingår i: Annals of the Rheumatic Diseases. - : British Medical Journal. - 0003-4967 .- 1468-2060. ; 52:5, s. 369-377
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To study the effects of long term (one year), long distance (up to 40 km/day) running on the metabolism of articular cartilage the biosynthesis of proteoglycans was examined by in vitro labelling of anterior (weight bearing) and posterior (less weight bearing) areas of the femoral head from young beagles.METHODS: Total sulphate incorporation rates were determined and distribution of the incorporated sulphate was localised by quantitative autoradiography. Concentration and extractability of the proteoglycans were determined, and proteoglycan structures were investigated by gel filtration chromatography, agarose gel electrophoresis, and chemical determinations.RESULTS: In the less weight bearing area the amount of extractable proteoglycans was decreased (p < or = 0.02), simultaneously with an increased concentration of residual glycosaminoglycans in the tissue after 4 M GuCl extraction (p < or = 0.05). In control animals proteoglycan synthesis was most active in the deep zone of the cartilage, whereas exercise increased synthesis in the intermediate zone. There was a tendency to a lower keratan: chondroitin sulphate ratio in the running dogs. No macroscopical or microscopical signs of articular degeneration or injury were visible in any of the animals.CONCLUSION: The articular cartilage of the femoral head showed a great capacity to adapt to the increased mechanical loading. The reduced proteoglycan extractability in the less weight bearing area changed it similar to the weight bearing area, suggesting that the low extractability of proteoglycans reflects the long term loading history of articular cartilage. The congruency of the femoral head with acetabulum seems to protect the cartilage from the untoward alterations that occur in the femoral condyles subjected to a similar running programme.
  •  
30.
  • Lammi, Mikko, 1961-, et al. (författare)
  • Effects of long-term running exercise on canine femoral head articular cartilage.
  • 1993
  • Ingår i: Agents and actions. Supplements. - : Birkhäuser Verlag. - 0379-0363. ; 39, s. 95-99
  • Tidskriftsartikel (refereegranskat)abstract
    • After long-term running program (40 km/day) anterior and posterior tissue samples from canine femoral head were labeled ex vivo in the presence of 35S-SO4. Sulfate incorporation rates did not differ between runner and control groups. The statistically significant changes in runners included a decreased uronic acid concentration (p < or = 0.02) and proportion of extractable proteoglycans (p < or = 0.05) as well as increased concentration of tissue uronic acid after 4 M GuCl extraction (p < or = 0.05) in the posterior area. These results support an idea of strengthened cartilage tissue after this kind of motion and load.
  •  
31.
  • Lammi, Mikko, 1961-, et al. (författare)
  • Hydrostatic pressure-induced changes in cellular protein synthesis.
  • 2004
  • Ingår i: Biorheology. - : IOS Press. - 0006-355X .- 1878-5034. ; 41:3-4, s. 309-313
  • Forskningsöversikt (refereegranskat)abstract
    • Hydrostatic pressure is a well-known effector of cellular protein synthesis. High continuous hydrostatic pressure inhibits protein synthesis in general. It has been known for a long time that 30S ribosomal subunit is associated with the effects of pressure on protein synthesis in prokaryotes, however, the mechanisms of action are still not completely understood. Our new data suggest that synthesis of eukaryotic elongation factor-2 (eEF-2) is decreased under 30 MPa continuous hydrostatic pressure. Thus, eEF-2 may have a role in the synthesis of pressure-regulated proteins in eukaryotic cells. The presence of pressure-sensitive proteins indicate that hydrostatic pressure can induce very specific responses in stressed cells. Accumulation of heat shock protein 70 and 90 beta occurs under high pressure, independent of the general inhibition of protein synthesis, although this response appears clearly weaker than during heat stress.
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32.
  • Lammi, Mikko, 1961-, et al. (författare)
  • Responses of mammalian cells to mechanical forces
  • 2001. - Vol. 1
  • Ingår i: Recent Research Developments in Biophysics and Biochemistry. - Trivandrum, India : Research Signpost. - 8177360574 ; , s. 77-89
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • All cells and tissues of our body are continuously subject to various mechanical stresses. These forces include, e.g., compression, shear stress, hydrostatic pressure and osmotic pressure. The range of forces vary from few pascals to several megapascals in magnitude. In many cases, mechanical forces are required for the tissues to maintain their normal functional structure and composition. However, excessive forces in the end may lead to adverse responses. In this paper, we review the data available from many different tissues in order to compare the signaling mechanisms involved in cellular mechanotransduction, and how the cells respond to forces that are too strenuous for them to withstand. The possible stress reactions caused by excessive forces are also discussed.
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33.
  • Lammi, Pirkko, et al. (författare)
  • Site-specific immunostaining for type X collagen in noncalcified articular cartilage of canine stifle knee joint.
  • 2002
  • Ingår i: Bone. - : Elsevier. - 8756-3282 .- 1873-2763. ; 31:6, s. 690-696
  • Tidskriftsartikel (refereegranskat)abstract
    • Type X collagen is a short-chain collagen that is strongly expressed in hypertrophic chondrocytes. In this study, we used an immunohistochemical technique exploiting a prolonged hyaluronidase unmasking of type X collagen epitopes to show that type X collagen is not restricted to calcified cartilage, but is also present in normal canine noncalcified articular cartilage. A 30 degrees valgus angulation procedure of the right tibia was performed in 15 dogs at the age of 3 months, whereas their nonoperated sister dogs served as controls. Samples were collected 7 and 18 months after the surgery and immunostained for type X collagen. The deposition of type X collagen increased during maturation from age 43 weeks to 91 weeks. In the patella, most of the noncalcified cartilage stained for type X collagen, whereas, in the patellar surface of the femur, it was present mainly in the femoral groove close to cartilage surface. In femoral condyles, the staining localized mostly in the superficial cartilage on the lateral and medial sides, but not in the central weight-bearing area. In tibial condyles, type X collagen was often observed close to the cartilage surface in medial parts of the condyles, although staining could also be seen in the deep zone of the cartilage. Staining for type X collagen appeared strongest at sites where the birefringence of polarized light was lowest, suggesting a colocalization of type X collagen with the collagen fibril arcades in the intermediate zone. No significant difference in type X collagen immunostaining was observed in lesion-free articular cartilage between controls and dogs that underwent a 30 degrees valgus osteotomy. In osteoarthritic lesions, however, there was strong immunostaining for both type X collagen and collagenase-induced collagen cleavage products. The presence of type X collagen in the transitional zone of cartilage in the patella, femoropatellar groove, and in tibial cartilage uncovered by menisci suggests that it may involve a modification of collagen fibril arrangement at the site of collagen fibril arcades, perhaps providing additional support to the collagen network.
  •  
34.
  • Lammi, Pirkko, et al. (författare)
  • Strong hyaluronan expression in the full-thickness rat articular cartilage repair tissue.
  • 2001
  • Ingår i: Histochemistry and Cell Biology. - : Springer. - 0948-6143 .- 1432-119X. ; 115:4, s. 301-308
  • Tidskriftsartikel (refereegranskat)abstract
    • Articular cartilage lesions have a poor capacity to regenerate. In full-depth articular cartilage defects, the repair process involves an ingrowth of mesenchymal cells from the bone marrow to the injured area, and these cells attempt to restore the lesion with cartilage-like repair tissue. In this study, we investigated histologically the distribution of hyaluronan in the rat repair tissue in relation to other glycosaminoglycans. Full-depth lesions were drilled to the weight-bearing region of rat medical femoral condyle. The rats were divided into two groups: intermittent active motion (IAM) and running training (RT) groups. In the RT group, programmed exercise was started 1 week after surgery, while the rats in the IAM group could move freely in their cages. The lesions were investigated 4 and 8 weeks after the surgery. Semiquantitative histological grading showed no significant differences in the repair between the groups. In normal articular cartilage, hyaluronan was stained mainly around chondrocytes. During repair, strong hyaluronan staining was observed in loose mesenchymal tissue, while in the repair area undergoing endochondral ossification, hyaluronan was intensively stained mainly around the hypertrophic chondrocytes. Remarkably strong staining for hyaluronan was noticed in areas of apparent mesenchymal progenitor cell invasion, the areas being simultaneously devoid of staining for keratan sulphate. In conclusion, hyaluronan is strongly expressed in the early cartilage repair tissue, and its staining intensity and distribution shows very sensitively abnormal articular cartilage structure.
  •  
35.
  • Långsjö, Teemu, et al. (författare)
  • Quantitative analysis of collagen network structure and fibril dimensions in cartilage repair with autologous chondrocyte transplantation.
  • 2010
  • Ingår i: Cells Tissues Organs. - : S. Karger AG. - 1422-6405 .- 1422-6421. ; 192:6, s. 351-360
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: The aim of this study was to undertake a stereological analysis to quantify the dimensions of the collagen network in the repair tissue of porcine joints after they had been subjected to autologous chondrocyte transplantation (ACT).METHOD: ACT was used to repair cartilage lesions in knee joints of pigs. Electron-microscopic stereology, immunostaining for type II collagen, and quantitative polarized-light microscopy were utilized to study the collagen fibrils in the repair tissue 3 and 12 months after the operation.RESULTS: The collagen volume density (V(V)) was lower in the repair tissue than in normal cartilage at 3 months (20.4 vs. 23.7%) after the operation. The collagen surface density (S(V), 1.5·10(-2) vs. 3.1·10(-2) nm(2)/nm(3)) and V(V) increased with time in the repair tissue (20.4 vs. 44.7%). Quantitative polarized-light microscopy detected a higher degree of collagen parallelism in the repair tissue at 3 months after the operation (55.7 vs. 49.7%). In contrast, 1 year after the operation, fibril parallelism was lower in the repair tissue than in the control cartilage (47.5 vs. 69.8%).CONCLUSION: Following ACT, V(V) and S(V) increased in the repair tissue with time, reflecting maturation of the tissue. One year after the operation, there was a lower level of fibril organization in the repair tissue than in the control cartilage. Thus, the newly synthesized collagen fibrils in the repair tissue appeared to form a denser network than in the control cartilage, but the fibrils remained more randomly oriented.
  •  
36.
  • Mäkelä, Olli, et al. (författare)
  • Analysis of lapine cartilage matrix after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate.
  • 2003
  • Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 62:1, s. 43-49
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To study the short and long term effects of radiosynovectomy on articular cartilage in growing and mature rabbits.METHODS: The articular cartilage of the distal femurs of rabbits was examined four days, two months, and one year after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate ([(166)Ho]FHMA). Arthritic changes were evaluated from histological sections by conventional and polarised light microscopy, and glycosaminoglycan measurements using safranin O staining, digital densitometry, and uronic acid determination. Proteoglycan synthesis was studied by metabolic [(35)]sulphate labelling followed by autoradiography, and electrophoretic analysis of extracted proteoglycans. Northern analyses were performed to determine the mRNA levels of type II collagen, aggrecan, and Sox9 in cartilage samples.RESULTS: Radiosynovectomy had no major effect on the histological appearance of articular cartilage in mature rabbits, whereas more fibrillation was seen in [(166)Ho]FHMA radiosynovectomised knee joints of growing rabbits two months after treatment, but not after one year. Radiosynovectomy did not cause changes in the glycosaminoglycan content of cartilage or in the synthesis or chemical structure of proteoglycans. No radiosynovectomy related changes were seen in the mRNA levels of type II collagen, whereas a transient down regulation of aggrecan and Sox9 mRNA levels was seen in young rabbits two months after [(166)Ho]FHMA radiosynovectomy.CONCLUSIONS: [(166)Ho]FHMA radiosynovectomy caused no obvious chondrocyte damage or osteoarthritic changes in mature rabbits, but in growing rabbits some transient radiation induced effects were seen--for example, mild cartilage fibrillation and down regulation of cartilage-specific genes.
  •  
37.
  • Mäkelä, Olli, et al. (författare)
  • Effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate on adult equine cartilage.
  • 2004
  • Ingår i: Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 31:2, s. 321-328
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To analyze the effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate (166Ho-FHMA) on articular cartilage in 6 adult horses.METHODS: Arthritic changes and mechanical properties of articular cartilage were evaluated with arthroscopy and postmortem microscopic analyses. Glycosaminoglycan content was measured by safranin-O staining combined with digital densitometry, uronic acid analyses, and dimethylene blue binding assay. 35S-sulfate labeling and autoradiography were used to localize proteoglycan synthesis and to characterize proteoglycan structures using SDS-agarose gel electrophoresis. Northern hybridizations were performed to measure the mRNA levels for aggrecan and pro-a1(II) collagen in cartilage samples.RESULTS: Histological signs of degeneration were present in the articular cartilage of both control and radiosynovectomized equine joints. Radiosynovectomy did not aggravate degenerative changes or significantly alter the matrix glycosaminoglycan content. A slightly decreased size of proteoglycan monomers was observed 2 months after 166Ho-FHMA radiosynovectomy. Tissue analysis of extracted proteoglycans revealed lower 35S incorporation after radiosynovectomy, but corresponding changes could not be observed in aggrecan mRNA levels. Transient downregulation of pro-a1(II) collagen mRNA transcription was observed 5 days after 166Ho-FHMA radiosynovectomy.CONCLUSION: 166Ho-FHMA treatment did not markedly affect the composition or morphology of adult articular cartilage showing mild degeneration. However, minor degradation of proteoglycan monomers and transient downregulation of pro-a1(II) collagen mRNA were observed.
  •  
38.
  • Panula, Harri E., et al. (författare)
  • Elevated levels of synovial fluid PLA2, stromelysin (MMP-3) and TIMP in early osteoarthrosis after tibial valgus osteotomy in young beagle dogs
  • 1998
  • Ingår i: Acta Orthopaedica Scandinavica. - 0001-6470. ; 69:2, s. 152-158
  • Tidskriftsartikel (refereegranskat)abstract
    • We determined the concentration of markers in cartilage and synovium metabolism in the synovial fluid (SF) of the knee of young beagle dogs with slowly progressive osteoarthrosis. Osteoarthrosis (OA) was induced by a tibial 30°valgus osteotomy to the right hindlimb of 16 dogs. The contralateral knee served as control. The animals were killed 7 (group I) and 18 months (group II) after operation. The levels in SF of chondroitin sulfate (CS), tissue inhibitor of metalloproteinases (TIMP-1), stromelysin (MMP-3), hyaluronan (HA), and the activity of phospholipase A2 enzyme (PLA2) were assayed. The first microscopic signs of cartilage degeneration were observed 7 months postoperatively and the lesions became more severe, including osteophyte formation during the following 11 months. The synovial fluid level of MMP-3 was higher (p = 0.04) at both time-points in the knee joint of the operated hindlimb than in the contralateral joint. On the operated side, 7 months postoperatively, synovial fluid PLA2 activity was higher (p = 0.02) than in the contralateral knee joint, but not 18 months postoperatively. The SF level of TIMP-1 was higher (p = 0.04) in the operated joint than in the contralateral joint 18 months after operation. The molar ratio of MMP-3 to TIMP-1 was higher (p = 0.001) in group II than in group I. The changes observed in the concentration of synovial fluid markers in this slowly progressive canine OA model suggest that activation of an inflammation-related process occurs at an early stage of the OA disease induced by unilateral tibial valgus osteotomy.
  •  
39.
  • Parkkinen, Jyrki, et al. (författare)
  • A mechanical apparatus with microprcessor controlled stress profile for cyclic compression of cultured articular cartilage explants
  • 1989
  • Ingår i: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 22:11-12, s. 1285-1291
  • Tidskriftsartikel (refereegranskat)abstract
    • An apparatus was designed for mechanical compression of cultured articular cartilage explants with a cylindrical plain-ended loading head (diameter 2–5 mm) driven by a stepping motor. A load cell under the culture dish was applied for feedback regulation utilizing a microprocessor-based control unit. The operating programs allowed either continuous or cyclic loading, the latter with adjustable loading/resting ratio. The improvements in the present design compared with previously described apparatuses for similar purposes include: (1) the accurately controlled compression by a load cell and a rapid feedback circuit; (2) the wide range of selectable stresses (25 kPa–12.5 MPa) with both continuous and cyclic loading modes; (3) the ability to handle cycles as short as 1 s with 15 ms peak loading phase. Using a 4s cycle and 0.5 MPa load for 1.5 h resulted in a significantly enhanced incorporation of radiosulphate in cultured bovine articular cartilage explants, suggesting a stimulation of proteoglycan synthesis. Light and scanning electron microscopic examinations revealed a slight depression and superficial alterations in cartilage structure at the impact site following high pressures. We expect that this apparatus will help in revealing how articular cartilage tissue and chondrocytes respond to external mechanical stimuli.
  •  
40.
  • Parkkinen, Jyrki, et al. (författare)
  • Altered Golgi apparatus in hydrostatically loaded articular cartilage chondrocytes.
  • 1993
  • Ingår i: Annals of the Rheumatic Diseases. - : British Medical Journal. - 0003-4967 .- 1468-2060. ; 52:3, s. 192-198
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: Articular cartilage proteoglycan content is controlled by joint loading. This study aimed to elucidate the role of hydrostatic pressure in this regulation.METHODS: Primary cultures of chondrocytes from bovine articular cartilage, grown on coverslips, were subjected to 5, 15, or 30 MPa hydrostatic pressure, applied continuously or cyclically at 0.125 or 0.05 Hz. The Golgi apparatus was visualised either by a fluorochrome coupled wheat germ agglutinin or by transmission electron microscopy. Proteoglycan synthesis was studied by the incorporation of sulphur-35 labelled sulphate.RESULTS: After 30 MPa continuous hydrostatic pressure, the Golgi apparatus was observed in a compact form with a concomitant decrease in proteoglycan synthesis. The normal stacked appearance of the Golgi apparatus was no more visible in the electron microscopy preparation of the pressurised chondrocytes. This effect was reversible and was also noticed after 15 MPa continuous load, though to a minor extent. Cyclic pressures (5-30 MPa) caused no apparent change in the Golgi apparatus. The shape of some cells changed to a more retracted form after 30 MPa continuous pressure. Nocodazole, which causes disassembly of the microtubules, blocked the compacting influence of pressurisation on the Golgi apparatus, and reduced proteoglycan synthesis to about half of the control level.CONCLUSIONS: The packing of the Golgi apparatus is dependent on microtubules and may contribute to the inhibition of proteoglycan synthesis observed in articular cartilage subjected to high hydrostatic pressure.
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41.
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42.
  • Parkkinen, Jyrki, et al. (författare)
  • Distribution of hyaluronan in articular cartilage as probed by a biotinylated binding region of aggrecan.
  • 1996
  • Ingår i: Histochemistry and Cell Biology. - : Springer. - 0948-6143 .- 1432-119X. ; 105:3, s. 187-194
  • Tidskriftsartikel (refereegranskat)abstract
    • The proportion of total tissue hyaluronan involved in interactions with aggrecan and link protein was estimated from extracts of canine knee articular cartilages using a biotinylated hyaluronan binding region-link protein complex (bHABC) of proteoglycan aggregate as a probe in an ELISA-like assay. Microscopic sections were stained with bHABC to reveal free hyaluronan in various sites and zones of the cartilages. Articular cartilage, cut into 20 microns-thick sections, was extracted with 4 M guanidinium chloride (GuCl). Aliquots of the extract (after removing GuCl) were assayed for hyaluronan, before and after papain digestion. The GuCl extraction residues were analyzed after solubilization by papain. It was found that 47-51% of total hyaluronan remained in the GuCl extraction residue, in contrast to the 8-15% of total proteoglycans. Analysis of the extract revealed that 24-50% of its hyaluronan was directly detectable with the probe, while 50-76% became available only after protease digestion. The extracellular matrix in cartilage sections was stained with the bHABC probe only in the superficial zone and the periphery of the articular surfaces, both sites known to have a relatively low proteoglycan concentration. Trypsin pretreatment of the sections enhanced the staining of the intermediate and deep zones, presumably by removing the steric obstruction caused by the chondroitin sulfate binding region of aggrecans. Enhanced matrix staining in these zones was also obtained by a limited digestion with chondroitinase ABC. The results indicate that a part of cartilage hyaluronan is free from endogenous binding proteins, such as aggrecan and link protein, but that the chondroitin sulfate-rich region of aggrecan inhibits its probing in intact tissue sections. Therefore, hyaluronan staining was more intense in cartilage areas with lower aggrecan content. A large proportion of hyaluronan resists GuCl extraction, even from 20-micrograms-thick tissue sections.
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43.
  • Parkkinen, Jyrki, et al. (författare)
  • Effects of cyclic hydrostatic pressure on proteoglycan synthesis in cultured chondrocytes and articular cartilage explants.
  • 1993
  • Ingår i: Archives of Biochemistry and Biophysics. - : Elsevier. - 0003-9861 .- 1096-0384. ; 300:1, s. 458-465
  • Tidskriftsartikel (refereegranskat)abstract
    • Primary chondrocyte cell cultures and explants of bovine articular cartilage were subjected to cyclic hydrostatic pressure in a novel computer-controlled pressure chamber designed for this purpose. The cultures were labeled with 5 microCi/ml 35SO4 and simultaneously pressurized with 5 MPa load for 1.5 or 20 h with pressure cycles of 0.0167, 0.05, 0.25, and 0.5 Hz. The chondrocyte cell cultures were also subjected to 0.0082 and 0.0034 Hz cycles. Sulfate incorporation was significantly inhibited in cell cultures subjected to the 0.5, 0.25, or 0.05 Hz cyclic loads for 1.5 h, but stimulated in explant cultures with a 0.5 Hz cyclic 1.5-h load. Chondrocyte cultures subjected to longer (20 h) loading showed a stimulation of sulfate incorporation with 0.5 and 0.25 Hz cycles, but an inhibition with 0.0167 Hz. The results indicate that cyclic hydrostatic pressures of presumably physiological magnitude have significant influences on proteoglycan synthesis in articular cartilage chondrocytes. Comparison of the cell and explant cultures under identical pressure conditions suggested that chondrocyte interactions with extracellular matrix are involved in this regulation by cyclic hydrostatic pressure. The responses of the chondrocytes to pressurization also varied according to the total length of the treatment, a finding compatible with the idea of multiple metabolic steps in chondrocytes, both pre- and post-translational, controlled by the ambient hydrostatic pressure.
  •  
44.
  • Parkkinen, Jyrki, et al. (författare)
  • Influence of short-term hydrostatic pressure on organization of stress fibers in cultured chondrocytes.
  • 1995
  • Ingår i: Journal of Orthopaedic Research. - : John Wiley & Sons. - 0736-0266 .- 1554-527X. ; 13:4, s. 495-502
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study describes changes in the organization of stress fibers that occur in articular cartilage chondrocytes subjected to hydrostatic pressure. Primary cultures of chondrocytes from bovine articular cartilage, grown on coverslips, were subjected to 5, 15, or 30 MPa hydrostatic pressure at 37 degrees C. The pressure was applied continuously or cyclically at two frequencies: 0.125 Hz (4 seconds of pressure and 4 seconds of no pressure) or 0.05 Hz (1 second of pressure and 19 seconds of no pressure) for a period of 2 hours. Control chondrocytes showed a polygonal form with prominent stress fibers extending across the cells. The exposure of cells to 30 MPa pressure caused a nearly total disappearance of stress fibers and retraction of the cells from each other. With pressure at 15 MPa or cyclic pressure, the number of cells with stress fibers was decreased. In cells subjected to 5 MPa pressure, the stress fibers resembled those in control chondrocytes. The pressure effects were reversible after 2 hours. Pressure had no effect on the staining pattern of vinculin, which suggests that microfilaments are more vulnerable to pressure than vinculin. The results indicate that cytoskeletal changes may be an integral part of the response of chondrocytes to hydrostatic pressure.
  •  
45.
  • Parkkinen, Jyrki, et al. (författare)
  • Local stimulation of proteoglycan synthesis in articular cartilage explants by dynamic compression in vitro.
  • 1992
  • Ingår i: Journal of Orthopaedic Research. - : John Wiley & Sons. - 0736-0266 .- 1554-527X. ; 10:5, s. 610-620
  • Tidskriftsartikel (refereegranskat)abstract
    • Cultured bovine articular cartilage was subjected to 50 ms, 0.5-1.0 MPa compressions repeated at intervals of 2-60 s for 1.5 h and simultaneously labeled with 35SO4. The compression was delivered with a 4-mm-diameter nonporous loading head on an 8-mm-diameter cartilage explant. This method created directly compressed (central) and uncompressed (border) areas within the tissue. Analysis of the whole explant under a 0.5 MPa load showed significantly increased 35SO4 incorporation by compression repeated at 2- and 4-s but not at 20- and 60-s intervals. When the incorporation was studied separately in the border and central areas, a statistically significant stimulation was noticed in the central area with a 4-s cycle, while the border area was stimulated with a 2-s cycle. Autoradiography of the central area showed that the stimulation with 0.5 MPa and a 4-s cycle occurred through the whole depth of the cartilage, while raising the pressure to 1 MPa or the frequency to 2 s reduced the stimulation, particularly in the superficial cartilage. In the border area the stimulation with 0.5 MPa and a 2-s cycle was noted in the superficial zone only. The stimulation of proteoglycan synthesis is thus limited to certain loading frequencies and pressures and occurs in specific areas under and around the loaded site. Its rapid appearance suggests enhanced glycosylation or sulfation of core proteins or enhanced speed of posttranslational processing.
  •  
46.
  •  
47.
  • Parkkinen, Jyrki, et al. (författare)
  • Quantitation of autoradiographic grains in different zones of articular cartilage with image analyzer.
  • 1990
  • Ingår i: Histochemistry. - : Springer. - 0301-5564. ; 93:3, s. 241-245
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel method is introduced for the estimation of grain numbers in autoradiographic sections of articular cartilage with an image analyzer. It is based on separation of grains from the underlying structures by gray level thresholding and determination of the percentage of total area occupied by grains in a relatively large measuring field. The mean grain size is used as a reference to calculate grain numbers per cell profile and per unit area of tissue in various zones of bovine articular cartilage labelled with 35S-sulphate in tissue culture. The results demonstrate considerable zonal differences as well as site related topographic variation in the rate of 35S-sulphate incorporation. The largest site-related variation in the grain counts was observed in the superficial zone, suggesting a delicate control of proteoglycan synthesis in this zone.
  •  
48.
  • Puustjärvi, Kaija, et al. (författare)
  • Flat bed scanner in the quantitative assay of 35SO4-incorporation by X-ray film autoradiography of intervertebral disc sections.
  • 1993
  • Ingår i: Histochemistry. - : Springer. - 0301-5564. ; 99:1, s. 67-73
  • Tidskriftsartikel (refereegranskat)abstract
    • 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.
  •  
49.
  • Puustjärvi, Kaija, et al. (författare)
  • Proteoglycan synthesis in canine intervertebral discs after long-distance running training.
  • 1993
  • Ingår i: Journal of Orthopaedic Research. - : John Wiley & Sons. - 0736-0266 .- 1554-527X. ; 11:5, s. 738-746
  • Tidskriftsartikel (refereegranskat)abstract
    • 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.
  •  
50.
  • Puustjärvi, Kaija, et al. (författare)
  • Proteoglycans in the intervertebral disc of young dogs following strenuous running exercise.
  • 1994
  • Ingår i: Connective Tissue Research. - : Informa Healthcare. - 0300-8207 .- 1607-8438. ; 30:3, s. 225-240
  • Tidskriftsartikel (refereegranskat)abstract
    • The proteoglycans (PGs) of intervertebral disc were studied in ten beagles which ran on a treadmill for one year (up to 40 km/day) and in ten non-running control dogs. Nucleus pulposus and annulus fibrosus from cervical (C5) and thoracic (T6 and T12) discs were labeled in vitro with 35SO4. The extractability, concentration and synthesis of PGs, and the electrophoretic subpopulations, aggregation and glycosaminoglycan chain lengths of newly-synthesized and total PGs were measured. Sulfate incorporation was significantly elevated by running in the C5 disc and reduced in the annulus of T6 discs. In the annulus of the T6 discs the concentration of total PGs was significantly lower although that of dermatan sulfate PGs was actually higher than in the controls. The results show that enhanced loading of the spine exerts significant alterations in the intervertebral disc PGs in a spine-level specific manner. In the most strained area of the spine (upper thoracic), the alterations in the runners suggest compromised biomechanical properties of the disc.
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