The effects of in situ freezing and the combination of in situ freezing and stress-shielding on the microstructure and ultrastructure of the patellar tendon were studied with use of 20 mature rabbits. The patellar tendon was frozen in situ with liquid nitrogen to kill fibroblasts and then was completely released from stress by chronically pulling a stainless-steel wire installed between the patella and the tibial tubercle. Microstructurally, the freezing treatment induced separation of collagen fiber bundles and fibroblast necrosis at 3 weeks, although the separation disappeared at 6 weeks. Ultrastructurally, small collagen fibrils with a diameter of less than 90 nm were predominant; at 6 weeks, the area occupied by collagen fibrils had decreased. In the frozen-shielded tendon, numerous large spaces were observed in the matrix at 3 weeks. This treatment increased the number of fibrils with a diameter greater than 360 nm and decreased the number of collagen fibrils per unit of area and the area occupied by collagen fibrils at 3 weeks. This study demonstrated that in situ freezing and the combination of in situ freezing and stress-shielding leads to a smaller volume of collagen fibrils per unit of cross section of the patellar tendon by mechanisms that remain to be defined.
We surveyed patients with Parkinson's disease living at home and elderly persons in hospital to find out causes of falls. In Parkinson's disease, the number of falls during the previous year increased with the progress of the grade of Hoehn and Yahr stage. The ratio of patients who had fractures due to falls was 0% in stage I & II, 30.2% in stage III, and 36.1% in stage IV. The ratio of patients who attached handrails was 30.1% in Hoehn and Yahr stage III, and 37.1% in stage IV; remodeling of hte bathroom was done in 30.7% and 51.0% remodeling of the laboratory was done in 42.5% and 53.8%, and bed adjustment in 24.3% and 43.8%. To prevent falls, we should advise patients to arrange the surroundings in which they spend the daytime such as their living room or bedroom. From the result of the ratios of patients in hospital who had falls and fractures due to falls, some associated risk factors of falls which could be prevented were found out. The ratio of patients who fell in the morning was reduced by interventions of nurses. The frequency of patients who fell was 41.5% in cerebrovascular disease, 29.5% in dementia, 11.2% in bone and joint disease, and 9.0% in Parkinson's disease, however the frequency in hospitalized patients was 56.9%, 11.3%, 7.3%, 6.3% respectively. Patients who had dementia had a tendency to fall. Further study is needed to help prevent of falls in dementia patients.
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