Test-Retest Reliability of Isokinetic Knee Strength Measurements in Type 2 Diabetes Mellitus Patients

Background: Reliability studies are used to verify the evaluation accuracy of a given device. Strength is an important factor for the development of daily activities and its correct management is fundamental. The objective of this study was to examine the reliability of a concentric strength test in people with type 2 diabetes mellitus (T2DM). Methods: Twenty-seven individuals with T2DM performed three repetitions of extension-flexion in concentric-concentric action at 60°/s, for both legs, using an isokinetic dynamometer. For the reliability analysis, we performed an intra-session test retest. Results: The total sample and men sub-group intra-class correlation coefficient (ICC) values were excellent for peak torque and work. In the women sub-group, ICC values were excellent for extensors in both peak torque and work; however, concerning flexor, the ICC values were good for peak torque while, for work, they were good for the right leg and moderate for the left leg. Standard error of measurement (SEM) percentage oscillated from 3.85% to 6.80%, with the smallest real difference (SRD) percentage being from 10.66% to 18.86% for peak torque. Furthermore, the SEM (%) was around 5.5% and SRD (%) was around 15% for work. Conclusions: The isokinetic dynamometry had “good” to “excellent” relative reliability for peak torque (0.862–0.983) and work (0.744–0.982) of extension-flexion in concentric-concentric action at 60°/s. In addition, our study showed that, in general, an SRD < 20% could indicate a true change in strength regarding this protocol in T2DM

Natural killer cells trigger osteoclastogenesis and bone destruction in arthritis

Osteoclasts are bone-eroding cells that develop from monocytic precursor cells in the presence of receptor activator of NF-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Osteoclasts are essential for physiological bone remodeling, but localized excessive osteoclast activity is responsible for the periarticular bone destruction that characteristically occurs in patients with rheumatoid arthritis (RA). The origin of osteoclasts at sites of bone erosion in RA is unknown. Natural killer (NK) cells, as well as monocytes, are abundant in the inflamed joints of patients with RA. We show here that such NK cells express both RANKL and M-CSF and are frequently associated with CD14+ monocytes in the RA synovium. Moreover, when synovial NK cells are cocultured with monocytes in vitro, they trigger their differentiation into osteoclasts, a process dependent on RANKL and M-CSF. As in RA, NK cells in the joints of mice with collagen-induced arthritis (CIA) express RANKL. Depletion of NK cells from mice before the induction of CIA reduces the severity of subsequent arthritis and almost completely prevents bone erosion. These results suggest that NK cells may play an important role in the destruction of bone associated with inflammatory arthritis

Methotrexate ameliorates pristane-induced arthritis by decreasing IFN-γ and IL-17A expressions*

Objective: This study was carried out to test the effects of methotrexate (MTX) and black seed oil (BSO) on pristane-induced arthritis (PIA) in rats. Methods: Inbred dark agouti (DA) rats were induced by a single subcutaneous injection of pristane, and then treated with MTX or BSO. Arthritis severity was evaluated macroscopically and microscopically. Plasma nitric oxide (NO) concentration was determined by the Griess method and cytokine mRNA expression in the spleen was detected by the real-time reverse transcription-polymerase chain reaction (RT-PCR). Results: The clinical arthritis severity was decreased after MTX treatment, while the BSO groups did not show significant changes compared with the disease group. The plasma NO level of the MTX group was significantly decreased compared with the disease group, but the BSO groups showed no difference from the disease group in plasma NO levels. The interferon-γ (IFN-γ) and interleukin-17A (IL-17A) mRNA expressions in the spleens were significantly decreased in the MTX group, but only showed a declining trend in the BSO groups compared with the disease group. Neither MTX nor BSO had an effect on the mRNA expressions of IL-4, transforming growth factor β (TGF-β), and tumor necrosis factor-α (TNF-α) in the spleen. Conclusions: MTX, but not BSO, can reduce the arthritis severity and decrease the mRNA expressions of IFN-γ and IL-17A in pristane-induced arthritis of rats