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- Lammi, Mikko, 1961-
(författare)
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Influences of in vivo and in vitro loading on the proteoglycan synthesis of articular cartilage chondrocytes
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this study, the biosynthesis of proteoglycans (PGs) was examined in articular cartilage of canine hip joint after long-distance running experiment and in bovine chondrocyte cultures during in vitro loading with hydrostatic pressure. In addition, new assays were developed for more sensitive quantitation of glycosaminoglycans (GAGs) and PGs.Anterior (weight-bearing) and posterior (less weight-bearing) areas of the femoral head from young beagles were labeled after long-term, longdistance running exercise. Total sulpahte incorporation rates were determined and distribution of of the incorporated sulphate in the tissue was localized by quantitative autoradiography. Concentration and extractability of the PGs were determined, and PG structures were studied by gel filtration, agarose gel electrophoresis, and chemical determinations. In the less weight-bearing area, the amount of extractable PGs was decreased, simultaneously with an increased concentration of residual GAGs in the tissue after 4M GuCl extraction. In the weight-bearing area, no marked alterations were noticed. The congruency of the femoral head seems to protect the cartilage from untoward alterations that occur in the femoral head condyles subjected to the same running program.The effect of hydrostatic pressure on PG metabolism of chondrocyte cultures was examined during 20 hours' exposure of chondrocytes to 5 and 30 MPa pressures. The continuous 30 MPa pressure reduced total PG synthesis by 37 % as measured by [35S]sulphate incorporation, in contrast to the 5 MPa which had no effect. Continuous 30 MPa hydrostatic pressure also reduced the steady-state mRNA level of aggrecan. The cyclic pressures showed a frequency dependent stimulation (0.5 Hz, + 11 %) or inhibition (0.017 Hz, -17 %). Aggrecans secreted under continuous 30 MPa pressure showed a retarded migration in 0.75 % SDS-agarose gel electrophoresis and also eluted earlier on Sephacryl S-1000 gel filtration, indicative of larger molecular size. The results demonstrate that high hydostatic pressure can influence the synthesis of PGs in chondrocytes both at the transcriptionl and translational/posttranslational levels.
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| 2. |
- Hedbrant, Johan, 1959-, et al.
(författare)
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Ny mätmetod för käkmuskulaturen kan finna orsaken till tinnitus : Slutrapport Nutek 92-11904
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tinnitus är en åkomma som i lindrigare eller allvarligare former drabbar 17% av västvärldens befolkning. Ca 85 000 svenskar har tinnitus på invalidiserande nivå. Förutom mänskligt lidande orsakar tinnitus samhällskostnader på ca 1.5 miljard kr årligen. Orsaken är till största delen okänd.Vissa tecken tyder på ett samband mellan tinnitus och funktionsstörning i en käkmuskel. Några olika icke–invasiva metoder för mätning av muskelstörning i M Pterygoideus Lateralis har utvärderas. Två av dessa är intressanta för fortsatta studier.Termografi användes för att diagnosticera muskelstörningar på ytligt liggande muskler. Vi såg åtskilliga varma områden på ytliga käk– och nackmuskler på de patienter som hade käkledsstörningar, samt möjligen tecken på onormal värme från M Pterygoideus Lateralis. Mätförhållandena var dock ej ideala.En metod att mäta EMG med adaptiv noise cancelling provades. EMG från en ryggmuskel, stört av en “EKG–signal” från hjärtat användes. Metoden fungerade bra. Fortsatt metodutveckling på t.ex. ryggmuskler borde göras.
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| 3. |
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| 4. |
- Brandt, Lennart, et al.
(författare)
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Myelography in the late postoperative period in patients subjected to anterior cervical decompression and fusion
- 1993
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Ingår i: Acta Neurochirurgica. - 0001-6268. ; 122:1-2, s. 97-101
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Tidskriftsartikel (refereegranskat)abstract
- During a 13 year period, 286 patients with cervical disc herniation and/or spondylotic spurs, were subjected to anterior decompression and vertebral interbody fusion with autologous bone. Twenty patients were re-admitted in the late postoperative period due to recurrent radicular symptoms and/or signs of myelopathy. In these patients myelography was performed again. In 14 patients spinal cord compression and/or nerve root involvement at a new level was visualized. At the operated level, however, the myelograms demonstrated a smooth anterior wall in the spinal canal. The series confirms the safety, effectiveness and reliability of the Cloward procedure in achieving long term spinal cord and nerve root decompression, and a solid vertebral interbody fusion.
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| 5. |
- Haapala, Jussi, et al.
(författare)
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Coordinated regulation of hyaluronan and aggrecan content in the articular cartilage of immobilized and exercised dogs.
- 1996
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Ingår i: Journal of Rheumatology. - : Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 23:9, s. 1586-1593
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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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| 6. |
- Király, Kari, et al.
(författare)
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Safranin O reduces loss of glycosaminoglycans from bovine articular cartilage during histological specimen preparation.
- 1996
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Ingår i: The Histochemical Journal. - : Chapman & Hill. - 0018-2214 .- 1573-6865. ; 28:2, s. 99-107
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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.
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| 7. |
- Bentzer, Peter, et al.
(författare)
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Supersensitivity in rat micro-arteries after short-term denervation
- 1997
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 161:2, s. 125-133
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Tidskriftsartikel (refereegranskat)abstract
- Contractile responses to phenylephrine and high-K+ were investigated in vitro in microvascular preparations from the rat medial plantar artery, a branch from the saphenous artery, obtained after short-term denervation in vivo. Two groups of animals were studied: (1) animals undergoing surgical resection of the saphenous nerve, and (2) animals undergoing surgical resection of both the sciatic and saphenous nerves. The animals were operated on one side only. Microvascular preparations (diameter about 325 microns) were obtained 10 days after surgery. Vessels from the non-operated side served as controls. Immunocytochemistry showed a decreased number of both neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) immunoreactive nerve fibres in vessels after resection of the saphenous nerve only. Resection of both the saphenous and the sciatic nerve caused a complete loss of immunoreactive nerve fibres. Mechanical measurements were performed using a wire myograph. In vessels subjected to resection of the saphenous nerve the sensitivity to phenylephrine was similar to controls. Vessels denervated by resection of both the saphenous and sciatic nerves showed significant increases in phenylephrine and potassium sensitivity. When depolarized in high-K+ solution the denervated vessels showed an increased sensitivity to extracellular Ca2+. The results show that complete short-term denervation of the rat medial plantar artery in vivo causes a pronounced supersensitivity in the vascular smooth muscle. The supersensitivity appears not to be restricted to the sympathetic alpha-receptors but also associated with changes in the cellular excitation-contraction coupling. Such altered reactivity of the vascular smooth muscle may contribute to vascular disturbances observed in vivo after nerve damage or surgical denervation.
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| 8. |
- Pettersson, Ulrika, 1970-
(författare)
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Bone mass in the young athlete
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bone mass and bone size accumulate during childhood and adolescence and peak in the twenties. The obtained peak bone mass has been suggested to be a major determinant of bone mass even in the very elderly. Although, genetic factors are the main determinants, environmental and lifestyle factors also play a crucial role in modulating maximal bone mass. Assessing these lifestyle factors would be of great importance for the intervention strategies against osteoporosis. The first aim of this thesis was to compare the bone mass and bone size in male and female young adults on a high level of physical activity with males or females on a low level of physical activity. Furthermore, it also aimed to investigate the influence of pubertal maturity, menstrual disturbances, and different body constitutional factors on bone mass and size during adolescence and young adulthood. The female activity groups consisted of cross-county skiers, soccer players, and rope skippers. Compared to their age-matched inactive controls, all these athletic groups demonstrated a significantly higher bone mineral density (BMD) at those sites subjected to the sport-specific loading. Rope-skipping, a very high impact activity was associated with a higher bone size, preferentially in the lower extremity, suggesting an effect of weight-bearing activity also on bone geometry. The effect of menstrual disturbances was evaluated in a group of long-distance runners, where amenorrheic runners had significantly lower BMD in both trabecular and also cortical bone in the lower extremity compared to eumenorrheic runners, suggesting that weight-bearing activity cannot compensate for the shortfall of reduced estrogen levels. The male activity groups consisted of ice hockey players and badminton players. Compared to their age-matched controls, both athletic groups demonstrated a significantly higher BMD at those sites subjected to the sport-specific loading. Especially badminton was associated with a high BMD, suggesting that physical activity, including jumps in unusual directions has a great osteogenic potential. The main determinants of BMD in both male and females were, except for type of physical activity, activity, muscle strength, height, and different body constitutional factors. However, the relationships with muscle strength and body constitution were somewhat weaker in the athletic groups, especially in the males, indicating that impact forces may be of greater importance in regulating bone mass in highly trained athletes. Yet bone size was largely determined by parameters related to body size and less strongly to physical activity. In a prospective study on adolescent boys, the changes in bone mass during late puberty were mainly accounted for by growth and development, including height and pubertal maturation, and less to physical activity level. Thus, the osteogenic effect from physical activity seems to be of importance for bone mass achievement predominantly before late puberty.
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| 9. |
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| 10. |
- Bengtsson, H, et al.
(författare)
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Expansion pattern and risk of rupture of abdominal aortic aneurysms that were not operated on
- 1993
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Ingår i: European Journal of Surgery. - 1102-4151. ; 159:9, s. 461-467
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To analyse the outcome of selective management of patients with abdominal aortic aneurysms, the expansion patterns of the aneurysms, and the factors that influenced the rate of rupture. DESIGN: Retrospective study. SETTING: Malmo General Hospital, Lund University, Malmo, Sweden. SUBJECTS: 155 patients (96 men and 59 women) with abdominal aortic aneurysms who were not selected for operation for whatever reason were included in the study immediately after their first ultrasound scan. MAIN OUTCOME MEASURES: Mortality, expansion rate (mm/year) measured on ultrasound scan, and rate of rupture of aneurysm. RESULTS: Median aneurysmal diameter was 40 mm (range 20-80), and length (n = 106) 70 (range 28-140). The patients were followed up for a median of 3.4 years (range 0-10.2). A total of 107 patients died and in 21 the aneurysms ruptured (4 were operated on and survived). Thirteen patients were re-evaluated and operated on electively. Ultrasonography was repeated in 98 patients, the median expansion rates (mm/year) were 3.1 (diameter) and 1.9 (length). There was a significant linear relationship between initial size (diameter and length) and rate of expansion of diameter. The risk of rupture was greater in larger aneurysms that were expanding more quickly. The cumulative mortality was not affected by the 21 aneurysms that ruptured. CONCLUSION: Selective management of patients with aortic aneurysms is justified.
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