Knockouts of Se-glutathione peroxidase-1 and Cu,Zn superoxide dismutase exert different impacts on femoral mechanical performance of growing mice.

The objective of this study was to determine the impact of knockout of Cu,Zn-superoxide dismutase (SOD1) and Se-glutathione peroxidase-1 (GPX1) on murine bone biomechanical properties. Femora samples were collected from wild-type (WT), SOD1-knockout [SOD1(-/-)] and GPX1-knockout [GPX1(-/-)] female mice (9-wk old, n = 7-8 per genotype) to assay for bone enzyme activities and mechanical properties in three point bending. Prior to testing, all mice were fed a torula yeast diet supplemented with 0.4 mg Se/kg as sodium selenite. Compared with the WT mice, SOD1(-/-) mice displayed a series of reductions (p < 0.05): 24% in body mass, 8% in femoral length, 43% in femoral structural strength, and 32% in bending stiffness. When differences in body size were accounted for, femoral failure moment in SOD1(-/-) mice remained lower (p < 0.05) than that of WT. Femoral tartrate resistant acid phosphatase activity in SOD1(-/-) was 47% greater (p < 0.05) than the WT. In contrast, GPX1(-/-) mice showed no significant differences in femoral mechanical properties from those of WT mice. In conclusion, knockout of SOD1 exerted a greater impact on femoral mechanical characteristics than that of GPX1 in growing mice.

Long-term monitoring of radioactivity in surface air and deposition in New York State.

Gross-beta activities have been determined weekly for 22 y from filtered atmospheric aerosols at seven sites in New York State. The activities, ranging from 0.1 to 0.9 mBq m(-3), varied seasonally and were evaluated in terms of meteorological factors. Cosmogenic beryllium (7Be) concentrations were determined quarterly on the air filters and weekly in deposition collected at one site. Over 98% of the air filters contained observable activity concentrations of 7Be (mean of 3 mBq m(-3)) and 210Pb (mean of 1 mBq m(-3)). However, only 20% of deposition samples contained Be concentrations above analytical detection limits. Tritium (3H) concentrations were below detection limits in deposition samples at the background site, but were present on most samples collected near a H-processing facility. Measurements of 131I were conducted weekly on charcoal canisters, with only one site showing observable concentrations (mean of 1 mBq m(-3)), due to nearby incineration of dried municipal sludge containing patient waste from hospital treatments.

Airborne 131I at a background monitoring site.

As part of an environmental surveillance program, measurements of 131I in samples of atmospheric aerosols were determined in week-long collection periods at 0.3 km and 1.5 km from a municipal-sewage sludge incinerator located in Albany, New York. During an 11-month period when the sampler was temporarily located near the incinerator, sampling canisters of activated charcoal nearly always contained detectable airborne 131I activity (range of 0.1-6.0 mBq m(-3)). In contrast, remote concentrations where the sample was normally located were near or below analytical detection limits, both before and after the 11-month relocation. Activities of wet and dry fallout at both locations were below detection limits. The source of 131I in the aerosols associated with the sewage sludge was likely excreta from patients following medical treatments at local hospitals.