Biomedical subjects
Publications and source records attributed to T Gustafsson.
The major chromomeres of pachytene chromosomes 6 and 11 in the oocytes of Acheta (Orthoptera) are regions of amplification for ribosomal RNA cistrons (28 S and 18 S). During late prophase the amplified DNA copies are released from the chromomeres, which decrease in size as the amount of DNA decreases. The number of nucleotide pairs released from the major chromomere of chromosome 11 is about 1.38 x 10(9).
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AIMS: Studies from genetically modified animals have been instrumental in highlighting genes and their products involved in the regulation of muscle fibre type and oxidative phenotypes; however, evidence in humans is limited. Our aim was therefore to investigate expression of those genes implicated in the regulation of oxidative fibre phenotypes in humans. METHODS: Using quantitative polymerase chain reaction we determined mRNA expression of selected genes in skeletal muscle from three different groups, displaying physiological and pathological variations in muscle fibre type, activity and skeletal muscle metabolism respectively: (i) elite athletes (cyclists), with an increased proportion of type I slow twitch, oxidative fibres, (ii) normally active subjects with an average fibre type distribution, and (iii) spinal cord-injured subjects with a low proportion of type I fibres. RESULTS: Skeletal muscle mRNA expression of calcineurin Aalpha and Abeta, peroxisome proliferator-activated receptor (PPAR)-alpha and -delta, and PPAR gamma coactivator (PGC)-1alpha and -1beta was determined. Calcineurin Aalpha and calcineurin Abeta mRNA expression was similar between groups. In contrast, mRNA expression of PPARalpha, PPARdelta, PGC-1alpha and -1beta was increased in athletes, when compared with normally active subjects. Furthermore, mRNA expression of PPARalpha, PPARdelta, PGC-1alpha and -1beta was reduced in spinal cord-injured subjects. Additionally, PPARalpha, PPARdelta and PGC-1alpha correlated with oxidative fibre content. CONCLUSION: Skeletal muscle mRNA expression of PPARalpha, PPARdelta, PGC-1alpha and -1beta reflects differences in type I muscle fibres associated with pathologically and physiologically induced skeletal muscle fibre type differences.
Arthroplasty for primary osteonecrosis of the femoral condyle of the knee was performed in 5 patients and the resected pieces of bone were studied histologically. The patients had been given 99 mm-Tc-MDP preoperatively and the scintimetric uptake in the resected bone pieces was determined. All patients had changes typical for osteonecrosis preoperatively on radiographs and scintimetry. In one case MRI investigation was performed. The histological investigation showed necrotic bone with empty lacunae and fatty degeneration corresponding to the osteonecrosis center. A reparative bone formation, osteoblastic activity, cartilage formation and bands of fibrovascular granulation tissue were observed at the borders to intact bone. The scintimetric uptake of the resected bone pieces showed a high uptake corresponding to the osteonecrosis center. The MR examination showed a well demarcated osteonecrotic region. The findings emphasize the localized nature of the osteonecrosis disease.