EFFECTS OF VARIOUS BIOMECHANICAL ERRORS ON COMPUTED JOINT KINETICS VALUES

Inverse dynamics analysis has been widely used to evaluate the joint kinetics during various human movements. Several investigators have reported that the joint kinetic computations could be considerably affected by diverse biomechanical errors. Kim et al (2007) clarified the influence of measurement errors of Center of Pressure (CoP) location of force platform on calculated three-dimensional (3D) lower limb joint moment during walking. However, it is not yet clear how biomechanical errors, such as errors in CoP, Body Segment Parameters (BSP) and Joint Center Location (JCL) data, affect the calculated joint kinetics values. The purpose of this study was to clarify the influences of the alterations of anthropometric, kinematic, and kinetic variables on the magnitude and time-series curve patterns of the 3D ankle joint moment during human running

Involvement of interleukin-8 in dialysis-related arthritis

Involvement of interleukin-8 in dialysis-related arthritis. To elucidate the role of interleukin (IL)-8, a chemotactic factor for neutrophils, in dialysis-related arthritis (DRA) of patients on long-term hemodialysis, the concentration of IL-8 was measured in the synovial fluids of DRA patients with acute arthralgia and joint swelling, and was compared with those in patients with rheumatoid arthritis (RA) and patients with osteoarthritis (OA). We noted a marked elevation of IL-8 in the joint fluids of patients with DRA and RA as compared with OA. Furthermore, to determine the role of IL-8 in synovitis, we examined the in vivo effect of intra-articular injection of human recombinant IL-8 on leukocyte infiltration into the joint space of rabbits. A single injection of IL-8 to the joints of rabbits induced rapid infiltration of neutrophils into the joint space and synovial tissues, which reached a maximum in four hours. The oral administration of indometacin farnesil (a prodrug that is converted to indomethacin after intestinal absorption) before the injection of IL-8 alleviated the infiltration of neutrophils. When human synovial cells were incubated with tumor necrosis factor (TNF)-α, the expression of IL-8 mRNA and IL-8 production in the cultured synovial cells were increased. The TNF-α-stimulated expression of IL-8 mRNA and IL-8 production in the cultured synovial cells were markedly inhibited by dexamethasone. In conclusion, IL-8 levels were markedly elevated in the joint fluids of patients with DRA. Interleukin-8 released from synovial cells may be an important factor to induce acute inflammation in DRA. Dexamethasone and indomethacin may be effective for DRA by inhibiting the production and chemotactic actions of IL-8, respectively

Men who were thin during early adulthood exhibited greater weight gain‐associated visceral fat accumulation in a study of middle‐aged Japanese men

ObjectiveThis study aimed to assess the relationship between weight gain from early adulthood and visceral fat accumulation.MethodsThe participants were 549 men aged 42 to 64 years who were randomly selected from the local resident registry for the National Institute for Longevity Sciences\u27 neighbourhood. They were asked to recall their weight at 18 years of age, and then, post‐18 weight‐change values were calculated for each participant (their current weight minus their weight at 18). The participants were divided according to their median body mass index (BMI) at 18 years of age (initial BMI) (<20.14 and ≥20.14 kg m−2). Visceral fat area (VFA) and subcutaneous fat area (SFA) were measured on computed tomography scans.ResultsThe participants with initial BMI of <20.14 kg m−2 exhibited greater post‐18 weight changes than those with initial BMI of ≥20.14 kg m−2. The participants\u27 post‐18 weight‐change values were negatively correlated with their initial BMI and positively correlated with both VFA and SFA. The slope of the regression line for the relationship between post‐18 weight change and VFA was steeper in the participants with initial BMI of <20.14 kg m−2 (β = 4.36) than in those with initial BMI of ≥20.14 kg m−2 (β = 3.23).ConclusionsVisceral fat accumulation is affected not only by an individual\u27s post‐18 weight gain but also by their initial BMI. Men who were thin in early adulthood experienced greater weight gain‐associated VFA increases, but the same was not true for SFA

The effect of modifiable healthy practices on higher-level functional capacity decline among Japanese community dwellers

This study aimed to clarify the effects of the accumulation of 8 modifiable practices related to health, including smoking, alcohol drinking, physical activity, sleeping hours, body mass index, dietary diversity, ikigai (life worth living), and health checkup status, on higher-level functional capacity decline among Japanese community dwellers. Data were derived from the National Institute for Longevity Sciences - Longitudinal Study of Aging. Subjects comprised 1269 men and women aged 40 to 79 years at baseline (1997–2000) who participated in a follow-up postal survey (2013). Higher-level functional capacity was measured using the Tokyo Metropolitan Institute of Gerontology Index of Competence (total score and 3 subscales: instrumental self-maintenance, intellectual activity, and social role). The odds ratio (OR) and 95% confidence interval (CI) for a decline in higher-level functional capacity in the follow-up study according to the total number of healthy practices were analyzed using the lowest category as a reference. Multivariate adjusted ORs (95% CIs) for the total score of higher-level functional capacity, which declined according to the total number of healthy practices (0–4, 5–6, 7–8 groups) were 1.00 (reference), 0.63 (0.44–0.92), and 0.54 (0.31–0.94). For the score of social role decline, multivariate adjusted ORs (95% CIs) were 1.00 (reference), 0.62 (0.40–0.97), and 0.46 (0.23–0.90), respectively (P for trend = 0.04). Having more modifiable healthy practices, especially in social roles, may protect against a decline in higher-level functional capacity among middle-aged and elderly community dwellers in Japan