BACKGROUND: Currently, the researches on knee plaster immobilization paralysis animal models are popular in the world, but there are some insufficiencies with the knee paralysis animals, for example, poor animal selection, inappropriate plaster selection and pure gypsum instability, which affect the subsequent results.
OBJECTIVE: To establish a rabbit model of knee paralysis by the knee fixation with plaster casts and wire.
METHODS: A total of 20 New Zealand white rabbits were randomly divided into two groups. Models of right knee paralysis were established and fixed by plaster casts and wire. Normal controls were considered as the control group. At 8 weeks after fixation, right knee and pathologic histology were observed in the right knee.
RESULTS AND CONCLUSION: The knee joints were translucent, smooth, and shiny, without the cartilage defect in the control group, and the cartilaginous elasticity and rigidity were good, and the arrangement of chondrocytes was normal. There were no inflammatory infiltrations in the articular capsule of the normal rabbits. In the model group, the knee joint was matt and opaque. Articular cartilage became thin, and showed poor elasticity. The cartilages were degenerated. Articular surface was rough, and had defects. There were smal amount of joint fluid or no joint fluid. Cartilage cel s shrank or disappeared, and the number of cartilage cel s reduced with degeneration and necrosis. Subchondral bone became sclerosis with trabecular bone of hyperplasia. The arrangement of cartilage cel s was disordered, with hyalinization and synovial vil ous hypertrophy. Cel clustering phenomenon was seen. There were a large number of lymphocytes, plasma cel s and neutrophil infiltration in cartilages. The typical pathological changes of the knee paralysis present in the rabbit cartilage. These results demonstrate that the rabbit model of knee paralysis can be successful y established by using fixation method with plaster casts and wire, which has the advantages of simple operation, strong fixation and no injury.

Objective To discuss the clinical features of behavioral and psychological symptoms of demen-tia(BPSD)and the relation between different sub-clinical syndromes and cognition. Methods One hundred and sixteen dementia patients were assessed with neuropsychiatric inventory and mini-mental state examination (MMSE)and made factor analysis according to DSM-IV-R. Results Twelve common behavioral and psychological symptoms could be further divided into five sub-syndromes,including disinhibition behavior,psychosis,agitation, emotion and apathy factors. MMSE total score and years of education entered regression equation of apathy factor (P<0.05). Conclusion BPSD can be divided into five factors and apathy factor are related with cognitive function.