Purpose:Recent studies have shown that low-intensity resistance training with vascular occlusion (kaatsu training) induces muscle hypertrophy. A local hypoxic environment facilitates muscle hypertrophy during kaatsu training. We postulated that muscle hypertrophy can be more efficiently induced by placing the entire body in a hypoxic environment to induce muscle hypoxia followed by resistance training.Methods:Fourteen male university students were randomly assigned to hypoxia (Hyp) and normoxia (Norm) groups (n = 7 per group). Each training session proceeded at an exercise intensity of 70% of 1 repetition maximum (RM), and comprised four sets of 10 repetitions of elbow extension and fexion. Students exercised twice weekly for 6 wk and then muscle hypertrophy was assessed by magnetic resonance imaging and muscle strength was evaluated based on 1RM.Results:Muscle hypertrophy was significantly greater for the Hyp-Ex (exercised fexor of the hypoxia group) than for the Hyp-N (nonexercised fexor of the hypoxia group) or Norm-Ex fexor (P < .05, Bonferroni correction). Muscle hypertrophy was significantly greater for the Hyp-Ex than the Hyp-N extensor. Muscle strength was significantly increased early (by week 3) in the Hyp-Ex, but not in the Norm-Ex group.Conclusion:This study suggests that resistance training under hypoxic conditions improves muscle strength and induces muscle hypertrophy faster than under normoxic conditions, thus representing a promising new training technique.

Infiltration of various types of leucocytes has been shown to play a crucial role in the pathogenesis of rheumatoid arthritis (RA). Macrophage inflammatory protein‐3α (MIP‐3α) is a recently identified chemokine which is a selective chemoattractant for leucocytes such as memory T cells, naïve B cells and immature dendritic cells. In this study, we investigated the expression of MIP‐3α and its specific receptor CCR6 in the inflamed joints of patients with RA. Increased amounts of MIP‐3α were found by ELISA in synovial fluids (SF) of patients with RA. MIP‐3α was apparently detected in all synovial tissue specimens of RA patients (n = 6), but it could not be detected in that of osteoarthritis (OA) patients (n = 4). Expression of MIP‐3α was detected especially in the sublining layer, and infiltrating mononuclear cells in RA synovial tissue. Gene expression of MIP‐3α was also found in six out of 11 RA‐synovial fluid cells by RT‐PCR. Cultured synovial fibroblasts derived from either RA or OA patients were capable of producing MIP‐3α in response to IL‐1β and TNFα in vitro. Furthermore, expression of CCR6 was found in infiltrating mononuclear cells in the cellular clusters and around the vessels of RA synovial tissue. These findings indicate that increased production of MIP‐3α may contribute to the selective recruitment of CCR6‐expressing cells in RA.

This longitudinal study aimed to identify risk factors for the incidence and progression of radiographic knee osteoarthritis (OA). We examined the inhabitants of Miyagawa village aged ≥65 years every two years between 1997 and 2007. Anteroposterior radiographs of both knees were graded for OA using the Kellgren-Lawrence (K/L) grading system. Knee OA was defined as grade ≥2. We recorded the incidence of knee OA among participants in whom both knees changed from K/L grades 0 or 1 to ≥2 over a four-year follow-up period. We also recorded the progression of knee OA using this threshold among patients in whom one or both knees changed from K/L grades 2 or 3 to any higher grade over the follow-up period. Baseline data obtained from standard questionnaires, physical findings and X-rays included age, gender, body mass index (BMI), osteoporosis, Heberden's nodes, knee range of motion (ROM), knee pain and cigarette smoking. The rates of incidence and progression of knee OA among 360 participants (241 women, 119 men) who fulfilled the study criteria were 4.0 and 6.0% per year, respectively. Female gender (odds ratio [OR] 2.849, 95% confidence interval [CI] 1.170-6.944) and high BMI (OR 1.243, 95% CI 1.095-1.411) were significantly associated with the incidence of knee OA, and restricted knee ROM (OR 0.941, 95% CI 0.892-0.992) was significantly associated with knee OA progression. Patients with a low knee ROM relative to grade of radiographic knee OA require more careful follow-up than those with a higher ROM.

BackgroundThe progression of disc degeneration is generally believed to be associated with low back pain and/or degenerative lumbar diseases, especially in the elderly. The purpose of this study was to quantitatively evaluate changes in lumbar disc height using radiographic measurements and to investigate risk factors for development of disc height narrowing of the elderly.MethodsFrom 1997 to 2007, 197 village inhabitants at least 65 years-old who participated in baseline examinations and more than four follow-up examinations conducted every second year were chosen as subjects for this study. Using lateral lumbar spine radiographs of each subject, L1-L2 to L5-S1 disc heights were measured. The subjects were divided into two groups according to the rate of change in disc height: mildly decreased (≤20 % decrease) and severely decreased (>20 % decrease). A stepwise multiple logistic regression analysis was used to select those factors significantly associated with disc height narrowing.ResultsDisc height at each intervertebral disc (IVD) level decreased gradually over ten years (p < 0.01, an average 5.8 % decrease of all disc levels). There was no significant difference in the rate of change in disc height among the IVD levels. Female gender, radiographic knee osteoarthritis and low back pain at baseline were associated with increased risk for disc height narrowing.ConclusionsWe conducted the first population-based cohort study of the elderly that quantitatively evaluated lumbar disc height using radiographic measurements. The risk factors identified in this study would contribute to a further understanding the pathology of disc degeneration.

A time lag was evident in recovery between postoperative symptoms and muscle power at 3 months. However, harvesting osteochondral grafts did not exert adverse effects on donor knee function in young athletes at 2 years after undergoing osteochondral autograft transplantation for capitellar osteochondritis dissecans.