Age-related changes in gait velocity and leg extension power in middle-aged and elderly people.

To prevent a decline in gait with age, it is necessary to investigate age-related changes in gait performance and detect related factors. The purpose of this study was to assess the association between gait ability and leg extension power among middle-aged and elderly people. Height, weight, maximum gait velocity (MGV) and leg extension power (LEP) were measured in 752 males and females who participated in the National Institute for Longevity Sciences, Longitudinal Study of Aging (NILS-LSA). Age-related changes in MGV and LEP and the association between MGV and LEP were assessed. There were significant decline trends in height, weight, MGV and LEP with advancing age (p < 0.001). MGV showed a significantly positive correlation with LEP (in males: r = 0.48 p < 0.001, in females: r = 0.47; p < 0.001). Subjects aged 60 yrs and over showed a significantly higher correlation than those under 60 yrs in males, but not in females, after adjustment for height and weight. Although the relationships between MGV and LEP were different by age and gender, LEP may be one of the important factors in maintaining gait ability.

Pirarubicin might partly circumvent the P-glycoprotein-mediated drug resistance of human breast cancer tissues.

BACKGROUND: Anthracyclines are the first line antitumor agents against breast cancer, and P-glycoprotein (Pgp) is thought to be the main resistance mechanism against these agents. We have evaluated the chemosensitivity of fresh surgical specimens of breast cancer and compared them with their Pgp-expression. MATERIALS AND METHODS: The in vitro chemosensitivity of 65 surgical specimens obtained from 63 patients with advanced breast cancer was assessed by the histoculture drug response assay (HDRA) using doxorubicin (DXR), pirarubicin [(2"R)-4'-tetrahydropyranyladriamycin: THP], and epirubicin (EPIR). Breast cancer tissues were plated onto collagen gel matrix and incubated with 15 micrograms of DXR or EPIR, or 17 micrograms of THP per ml for 7 days with MTT assessed at the endpoint. The efficacy of the agents was evaluated by the inhibition index (I.I.) of the optical density detected by ELISA reader. RESULTS: When 60% or more I.I. was regarded as in vitro sensitive at each cut-off concentration of the drugs, the overall efficacy rates were 60.7%, 48.6%, and 78.6% for DXR, EPIR, and THP, respectively. Fifty-one surgical specimens were evaluated for the immunohistochemical analysis of Pgp and the correlation between the sensitivity to anthracyclines and the expression of Pgp was compared. Pgp was expressed in 23.5% (12/51) specimens and the efficacy of anthracyclines was reduced in Pgp-positive breast cancer tissues, although this reduction was low in THP with a statistically significant difference when comparing with DXR and EPIR. CONCLUSION: The present results suggest that THP might partly circumvent the mdr1/PgP-mediated drug resistance mechanism in human breast cancer tissue and would have some different antitumor spectra on breast cancer comparing with DXR and EPIR.