CONTINUOUS CHANGES IN LEG STIFFNESS USING A MASS-SPRING-DAMPER MODEL WITH AN ACTUATOR DURING THE STEP PHASE OF THE TRIPLE JUMP

The purpose of this study was to examine a calculation method of the leg stiffness using the simplified leg model for evaluating the continuous changes in leg stiffness during the step phase of the triple jump. The leg stiffness is the ratio of the ground reaction forces to a displacement of the simplified leg length. We compared the difference in the leg stiffness between the previous method and the proposed method in this study. There was a non-linear and exponential relationship between the displacement of the simplified leg length and the elastic force. The peak value of leg stiffness calculated by the previous method was larger than that by the mass-spring-damper model with an actuator of the proposed method in this study. The previous method could overestimate the leg stiffness during the triple jump. The leg stiffness of the proposed method has a potential for representing the muscle-tendon behaviors during the triple jump

Increase in Matrix Metalloproteinase-2 and 9 in the Liver of Nonalcoholic Steatohepatitis (NASH) Model Rats

Nonalcoholic steatohepatitis (NASH) is regarded as a hepatic manifestation of the metabolic syndrome which can progress to hepatic cirrhosis and hepatocellular carcinoma. It is thought that matrix metalloproteinases (MMPs) play an important role in hepatic fibrosis and we previously reported a correlation between oxidative stress and MMP-9 expression. However, the expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in the progression of NASH is unclear. In this study we used spontaneously hypertensive and hyperlipidemic rats (SHHR) fed a high-fat diet and 30% sucrose solution (HFDS) as a model for NASH, in order to clarify the relationships between oxidative stress, liver weight (LW), MMPs and TIMPs at various time-points in the progression of NASH. Male SHHR and Sprague-Dawley (SD) rats were divided into four groups: SHHR-normal diet (ND), SHHR-HFDS, SD-ND and SD-HFDS. Hepatic fibrosis was clearly increased at 13 months in SHHR-HFDS, resembpling NASH. LW and oxidative stress markers in plasma were increased in SHHR-HFDS compared to the other groups. Oxidative stress was correlated with LW in all rats. Expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 mRNA, measured by real-time polymerase chain reaction, was increased in the liver of SHHR-HFDS at 13 months. This study suggests that oxidative stress, MMPs and TIMPs may play an important role in the progression of NASH

E3 Ubiquitin Ligase Synoviolin Is Involved in Liver Fibrogenesis

Chronic hepatic damage leads to liver fibrosis, which is characterized by the accumulation of collagen-rich extracellular matrix. However, the mechanism by which E3 ubiquitin ligase is involved in collagen synthesis in liver fibrosis is incompletely understood. This study aimed to explore the involvement of the E3 ubiquitin ligase synoviolin (Syno) in liver fibrosis.The expression and localization of synoviolin in the liver were analyzed in CCl(4)-induced hepatic injury models and human cirrhosis tissues. The degree of liver fibrosis and the number of activated hepatic stellate cells (HSCs) was compared between wild type (wt) and Syno(+/-) mice in the chronic hepatic injury model. We compared the ratio of apoptosis in activated HSCs between wt and Syno(+/-) mice. We also analyzed the effect of synoviolin on collagen synthesis in the cell line from HSCs (LX-2) using siRNA-synoviolin and a mutant synoviolin in which E3 ligase activity was abolished. Furthermore, we compared collagen synthesis between wt and Syno(-/-) mice embryonic fibroblasts (MEF) using quantitative RT-PCR, western blotting, and collagen assay; then, we immunohistochemically analyzed the localization of collagen in Syno(-/-) MEF cells.In the hepatic injury model as well as in cirrhosis, synoviolin was upregulated in the activated HSCs, while Syno(+/-) mice developed significantly less liver fibrosis than in wt mice. The number of activated HSCs was decreased in Syno(+/-) mice, and some of these cells showed apoptosis. Furthermore, collagen expression in LX-2 cells was upregulated by synoviolin overexpression, while synoviolin knockdown led to reduced collagen expression. Moreover, in Syno(-/-) MEF cells, the amounts of intracellular and secreted mature collagen were significantly decreased, and procollagen was abnormally accumulated in the endoplasmic reticulum.Our findings demonstrate the importance of the E3 ubiquitin ligase synoviolin in liver fibrosis

Small renal cell carcinoma accompanied by extensive inferior vena cava tumor thrombus diagnosed by percutaneous transvenous biopsy

Introduction Up to 10% of patients with renal cell carcinoma present with tumor thrombus in the inferior vena cava. We report that a case of small renal cell carcinoma with tumor thrombus extending above the diaphragm for which transvenous biopsy was performed for diagnosis. Case presentation A 79‐year‐old man performed computed tomography to evaluate hepatic dysfunction, which revealed intravenous tumor extending above the diaphragm and a 15‐mm‐sized exophytic tumor in right kidney. Imaging suggested that the renal tumor was renal cell carcinoma. As this tumor was small and exophytic, confirmation of the intravenous tumor being tumor thrombus associated with renal cell carcinoma was difficult. We simultaneously performed transvenous biopsy on the intravenous tumor and percutaneous biopsy on the renal tumor for obtaining histologic diagnoses. The final diagnosis was small renal cell carcinoma accompanied by tumor thrombus above the diaphragm. Conclusion Transvenous biopsy may be useful for the definitive diagnosis of inferior vena cava‐tumor thrombus in cases of small renal cell carcinoma