ABSTRACT
OBJECTIVES: The purpose of this study was to examine if there is a relationship between lower-extremity muscle performance (LEMP) and physical activity, especially the physical activity level (PAL) value, in community-dwelling middle-aged and older adults. DESIGN: Cross-sectional study. SETTING: Community-based. PARTICIPANTS: Participants were 54 community-dwelling and independent middle-aged and older individuals (aged 54-89 years). MEASUREMENTS: Physical activity level was calculated from the total energy expenditure of each participant obtained using the doubly labeled water method (PALDLW) and estimated basal metabolic rate. Daily step count and intensity of physical activity was monitored with a triaxial accelerometer, and LEMP was assessed using the five-repetition sit-to-stand test (STS-5) and vertical jumping (VJ). RESULTS: The results of STS-5 nearly negatively correlated with those of PALDLW when analysing the middle-aged and older man and woman, separately. VJ positively correlated with PALDLW when analysing the middle-aged and older men and woman, separately. The relationship between LEMP (e.g. STS-5 and VJ) and PAL were maintained, regardless of sex and body composition. PALDLW was significantly positively correlated with LPA, MVPA, and steps, and significantly negatively correlated with sedentary time. The relationship PALDLW and steps was described as following equation: PALDLW = 0.0000392 × steps +1.531. CONCLUSIONS: These findings suggest that PALDLW is a key contributor to increasing LEMP among middle-aged and older adults. Maintaining high PALDLW may be beneficial to independent living, and participation in recreational and social activities in middle-aged and older adults.
Subject(s)
Accelerometry/methods , Exercise/physiology , Lower Extremity/physiopathology , Muscles/physiopathology , Water/metabolism , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Male , Middle AgedABSTRACT
The temporal and spatial immunolocalization of TGF-betas and their receptors in the intervertebral disk of senescence-accelerated mouse (SAM) was examined to determine the biological roles played by TGF-betas and their receptors in the process of intervertebral disk degeneration. Ten male SAM and ICR mice aged 8, 24 or 50 weeks after birth were used for this experiment. Histological and immunohistochemical studies using specific antibodies for TGF-beta1, -beta2, -beta3, TbetaR-I, and TbetaR-II were performed. Intervertebral disks of SAM exhibited more degenerative changes than those of ICR mice. Expression of TGF-betas and TbetaRs in disk of SAM and ICR mice was observed at 8 weeks of age, and became weaker with aging. Our results suggest TGF-betas may play a role in the growth and maintenance of intervertebal disks.
Subject(s)
Aging, Premature/metabolism , Intervertebral Disc/chemistry , Protein Isoforms/analysis , Receptors, Transforming Growth Factor beta/analysis , Transforming Growth Factor beta/analysis , Aging, Premature/genetics , Aging, Premature/pathology , Animals , Immunoenzyme Techniques , Intervertebral Disc/pathology , Male , Mice , Mice, Inbred AKR , Mice, Inbred ICR , Mice, Mutant StrainsABSTRACT
STUDY DESIGN: Immunohistochemical study of expression and localization of bone morphogenetic protein (BMP)-2/4 and type I and II receptors on intervertebral disc. OBJECTIVES: To determine the biologic functions of BMPs and their receptors in the process of degeneration of the intervertebral disc. SUMMARY OF BACKGROUND DATA: Biologic and pathologic processes in the cell during the degeneration of the intervertebral disc are as yet poorly understood. METHODS: The cervical spines of 15 male senescence-accelerated mice aged 8, 24, or 50 weeks were used for histologic and immunohistochemical examination of BMP-2/4 and BMP receptors IA, IB, and II. Immunostaining was performed with the avidin-biotin-peroxidase complex method. RESULTS: Degenerative change was recognized within intervertebral discs of senescence-accelerated mice aged 50 weeks. BMP-2/4 and its receptors were abundant in hyaline cartilaginous cells within the endplate of the vertebrae at 8 and 24 weeks of age. However, the expression of BMP-2/4 and its receptors moved from the hyaline cartilage of the endplate of the vertebrae to fibrous cells within the anulus and to the calcified cartilage at the site of enthesis of mice aged 50 weeks. CONCLUSIONS: BMP-2/4 and its receptors may play roles in degenerative change of intervertebral disc.
