Comparability of the 6-min walk test using different test configurations.

The 6-min walk test (6MWT) is a common component of fitness assessments of older adults; however, differing course configurations might affect 6MWT performance. It is unclear how comparable 2 different configurations are. To determine the comparability of 2 courses, 35 adults >65 years of age completed two 6MWT, once walking around a 20- by 5-yd outdoor rectangle and once on an indoor oval track (circumference 144.3 yd). Scores for the 2 tests were internally consistent (intraclass correlation coefficient = .95). The participants walked farther on the oval track than around the rectangle (639 +/- 19 vs. 582 +/- 16 yd; p < .0001), but responses to the rectangular configuration could be readily estimated using the equation 66.7 yd + 0.807 x (oval walking distance), R2 = .85. Thus, within-participant responses are similar across both 6MWT, but the course configuration affects the distance walked.

Year-and-a-half old, dried Echinacea roots retain cytokine-modulating capabilities in an in vitro human older adult model of influenza vaccination.

Alcohol tinctures prepared from aged Echinacea roots are typically taken for preventing or treating upper respiratory infections, as they are purported to stimulate immunity in this context. The effects of long-term (> 1 year) dry storage on the capabilities of Echinacea spp. roots from mature individuals to modulate cytokine production are unknown. Using an older human adult model of influenza vaccination, we collected peripheral blood mononuclear cells from subjects 6 months post-vaccination and stimulated them in vitro with the two Type A influenza viruses contained in the trivalent 2004-2005 vaccine with a 50 % alcohol tincture prepared from the roots of one of seven Echinacea species: E. angustifolia, E. pallida, E. paradoxa, E. purpurea, E. sanguinea, E. simulata, and E. tennesseensis. Before being processed into extracts, all roots had been stored under dry conditions for sixteen months. Cells were cultured for 48 hours; following incubation, supernatants were collected and assayed for interleukin-2, interleukin-10, and interferon-gamma production, cytokines important in the immune response to viral infection. Four species ( E. angustifolia, E. purpurea, E. simulata, E. tennesseensis) augmented IL-10 production, diminished IL-2 production, and had no effect on IFN-gamma production. Echinacea pallida suppressed production of all cytokines; E. paradoxa and E. sanguinea behaved similarly, although to a lesser extent. The results from these in vitro bioactivity assays indicate that dried Echinacea roots stored for sixteen months maintain cytokine-modulating capacities. Our data support and extend previous research and indicate that tinctures from different Echinacea species have different patterns of immune modulation; further, they indicate that certain species may be efficacious in the immune response to viral infection.