Proinflammatory cytokines and arthroscopic findings of patients with internal derangement and osteoarthritis of the temporomandibular joint.

This study investigated the correlations between the concentrations of proinflammatory cytokines in synovial fluid and the degree of synovitis on the one hand, and the degree of degeneration of articular cartilage on the other hand, in patients with internal derangement and osteoarthritis of the temporomandibular joint. We measured the concentrations of interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha), IL-6 and IL-8 in synovial fluid and the degree of arthroscopic synovitis and degeneration of articular cartilage in 37 joints with internal derangement and osteoarthritis. The correlations between the concentration of each cytokine and the score of each arthroscopic feature were analysed statistically. The detection rates of IL-1beta,TNF-alpha, IL-6 and IL-8 were 57%, 78%, 89% and 70%, respectively. There was a positive correlation between the IL-6 concentration and the synovitis score (P = 0.02). Measurement of IL-6 in synovial fluid might be useful as an indicator of the extent of synovitis.

Does joint effusion on T2 magnetic resonance images reflect synovitis? Comparison of arthroscopic findings in internal derangements of the temporomandibular joint.

OBJECTIVE: The purpose of this study was to clarify the characteristics of joint effusion (JE) in the temporomandibular joint by comparing T2-weighted magnetic resonance (MR) images with arthroscopic findings. STUDY DESIGN: MR images of 47 symptomatic temporomandibular joints (47 patients) with internal derangement associated with painful hypomobility were taken to evaluate the degree of JE on a scale of 0 to 3. Within 2 months after MR images, arthroscopic findings with respect to the severity of synovitis, adhesion, and degenerative change in the superior compartment were each quantitatively assessed on a scale of 0 to 10. The arthroscopic scores were compared among the 4 JE grades, as well as between 2 groups, effusion-present (grades 2 and 3) and effusion-absent (grades 0 and 1), by using the Spearman correlation coefficient and the Mann-Whitney U test. RESULTS: The distribution of JE was as follows: 10 joints had grade 0, 5 joints had grade 1, 19 joints had grade 2, and 13 joints had grade 3. The synovitis score had a significant relationship to the degree of effusion (P =.0012) and was higher in the effusion-present group (6.4 +/- 2.0) than in the effusion-absent group (4.2 +/- 1.6) (P =.0005) On the other hand, there was no statistically significant correlation between either adhesion or degenerative change and effusion. CONCLUSIONS: JE may reflect synovitis; however, the nature of JE itself needs to be further elucidated by additional studies.

Increase of heat-shock protein and induction of gamma/delta T cells in peritoneal exudate of mice after injection of live Fusobacterium nucleatum.

Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans are Gram-negative rod periodontal pathogens. The peritoneal cavity of Institute of Cancer Research (ICR) mice was used as the local infection model. In vivo production of heat-shock proteins (hsp) was studied by injection of 1/10 minimum lethal dose (MLD) of each live bacteria into mice. Heat-shock proteins 70 and 60 were examined in the extract of peritoneal exudate cells (PEC) from mice injected intraperitoneally with either F. nucleatum or A. actinomycetemcomitans by using sodium dodecylsulphate-polyacrylamide gel electrophoresis and immunoblotting analysis. Although hsp are present in PEC without injection of the bacteria, both hsp increased and reached a peak on day 3 after F. nucleatum injection but not after A. actinomycetemcomitans. Kinetic study of gamma/delta cells in PEC after injection of bacteria showed that the increase of gamma/delta T cells was observed only in the PEC from mice injected with F. nucleatum but not A. actinomycetemcomitans. The gamma/delta T cells in PEC were either CD3+ and CD4+ or CD3+ and CD8+. The differential cell count of PEC suggested that gamma/delta T-cell induction is related to the expansion of the macrophage population. The phagocytic and chemiluminescence responses of macrophages against the same bacteria were compared after intensive immunization with live F. nucleatum and A. actinomycetemcomitans. Elevations of chemiluminescence response and phagocytic function by immunization were observed in the macrophages of mice immunized with F. nucleatum. These results suggest the sequential appearance of hsp, gamma/delta T cells and macrophage activation after fusobacterial infection.

Muscle metabolism during exercise using phosphorus-31 nuclear magnetic resonance spectroscopy in adolescents.

Very little has been reported on muscle energetics during exercise in adolescents. This is attributable to the difficulty of subjecting children to muscle biopsy. The purpose of this study was to investigate the characteristics of muscle metabolism during exercise in vivo in adolescents by comparing firstly, with adults and secondly, the differences resulting from physical activity using phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy. The subjects were boys aged 12 to 15 years, comprising 21 trained boys and 23 control boys, and 6 adults controls. The ratio of phosphocreatine (PCr):(PCr + P(i)), where P(i) is inorganic phosphate intracellular pH at exhaustion and the time constant of PCr during recovery were measured in all the subjects using 31P NMR. Both groups of children showed higher values of PCr:(PCr + P(i)) and intracellular pH at exhaustion than did the adult control group (P < 0.01 or P < 0.05). However, no significant differences were found between the trained boys and the control boys with respect to PCr:(PCr + P(i)) and intracellular pH at exhaustion. On the other hand, we found the same values for PCr time constant in all groups. This result suggested no differences of the muscle oxidative capacity between children and adults. We concluded that the adolescents, aged 12 to 15 years in both the trained and control groups, had less glycolytic ability during exercise than the adults.