Muscle strengthening exercises with or without weight-bearing and aerobic exercises are effective for pain relief in people with knee osteoarthritis. In particular, for pain relief by short-term exercise intervention, the most effective exercise among the three types is non-weight-bearing strengthening exercise.
As the incidences of cardiovascular diseases have been on the rise in recent years, the need for small-diameter artificial vascular grafts is increasing globally. Although synthetic polymers such as expanded polytetrafluoroethylene or poly(ethylene terephthalate) have been successfully used for artificial vascular grafts ≥6 mm in diameter, they fail at smaller diameters (<6 mm) due to thrombus formation and intimal hyperplasia. Thus, development of vascular grafts for small diameter vessel replacement that are <6 mm in diameter remains a major clinical challenge. Silk fibroin (SF) from Bombyx mori silkworm is well-known as an excellent textile and also has been used as suture material in surgery for more than 2000 years. Many attempts to develop small-diameter SF vascular grafts with <6 mm in diameter have been reported. Here, research and development in small-diameter vascular grafts with SF are reviewed as follows: (1) the heterogeneous structure of SF fiber (Silk II), including the packing arrangements and type II β-turn structure of SF (Silk I*) before spinning; (2) SF modified by transgenic silkworm, which is more suitable for vascular grafts; (3) preparation of small-diameter SF vascular grafts; (4) characterization of SF in the hydrated state, including dynamics of water molecules by nuclear magnetic resonance; and (5) evaluation of the SF grafts by in vivo implantation experiment. According to the findings, SF is a promising material for small-diameter vascular graft development.
Development of a small-diameter artificial vascular graft is urgent because existing materials often occlude within a short time. We have shown that small-diameter vascular graft using Bombyx mori silk fibroin is a potential candidate. Silk fibroin grafts are fabricated by coating silk fibroin on the knit tube prepared from silk fibroin fibers. However, there is a serious problem that the coated silk fibroin portion hardens when alcohol is used for insolubilization of the coated silk fibroin. This hardening prevents the desired biodegradation of the coated silk fibroin. In this study, we improved the silk fibroin coating method of the knit silk fibroin tube. Namely, the silk fibroin sponge coating was performed using glycerin, poly(ethylene glycol diglycidyl ether) or poly(ethylene glycol). In addition, silk fibroin grafts were prepared avoiding dryness during the coating process and were kept in the hydrated state until implantation into the abdominal aorta was complete. After implantation of the hydrated silk fibroin grafts, grafts were taken out at two weeks or three months, and histopathological examination was performed. The grafts coated with three types of silk fibroin sponges had a higher tissue infiltration rate than alcohol-treated grafts and were superior in the formation of smooth muscle cell and vascular endothelial cell remodeling. Biodegradations of the silk fibroin grafts prepared using the three types of silk fibroin sponge coatings and alcohol-treated silk fibroin grafts were also examined with protease XIV in vitro, and the grafts were observed by scanning electron microscopy before and 24 h after biodegradation. Faster biodegradations were observed for grafts coated with the three types of silk fibroin sponges. C solid-state nuclear magnetic resonance studies showed that the conformation of the silk fibroin sponge prepared using porogen was a random coil with high mobility in the hydrated state. We believe that small-diameter silk fibroin vascular grafts coated with quick biodegradable silk fibroin sponges can be developed based on these findings.
Background Joint contractures are a common complication of many neurologic conditions, and stretching often is advocated to prevent and treat these contractures. However, the magnitude and duration of the stretching done in practice usually are guided by subjective clinical impressions. Questions/purposes Using an established T8 spinal cord injury rat model of knee contracture, we sought to determine what combination of static or intermittent stretching, varied by magnitude (high or low) and duration (long or short), leads to the best (1) improvement in the limitation in ROM; (2) restoration of the muscular and articular factors leading to contractures; and (3) prevention and treatment of contracture-associated histologic alterations of joint capsule and articular cartilage. Methods Using a rat animal model, the spinal cord was transected completely at the level of T8. The rats were randomly assigned to seven treatment groups (n = 4 per group), which were composed of static or intermittent stretching in combination with different amounts of applied torque magnitude and duration. We assessed the effect of stretching by measuring the ROM and evaluating the histologic alteration of the capsule and cartilage. Results Contractures improved in all treated groups except for the low-torque and short-duration static stretching conditions. High-torque stretching was effective against shortening of the synovial membrane and adhesions in the posterosuperior regions. Collagen Type II and VEGF in the cartilage were increased by stretching. Conclusions High-torque and long-duration static stretching led to greater restoration of ROM than the other torque and duration treatment groups. Stretching was more effective in improving articular components of contractures compared with the muscular components. Stretching in this rat model prevented shortening and adhesion of the joint capsule, and affected biochemical composition, but did not change morphologic features of the cartilage. Clinical Relevance This animal study tends to support the ideas that static stretching can influence joint ROM and histologic qualities of joint tissues, and that the way stretching is performed influences its efficacy. However, further studies are warranted to determine if our findings are clinically applicable.
These observations indicated that nuclear accumulation of AR was associated with the gender difference in LMNA-linked DCM.
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