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Background:The purpose of this study was to assess participants’ ability to perform tasks requiring attention, short term memory, and simple motor skill while sitting, standing or walking at an active workstation.Methods:Fifty participants completed the Stroop Color Word test (SCWT), Auditory Consonant Trigram test (ACTT), and Digital Finger Tapping test (DFTT) while sitting, standing and walking 1.6 km/h at an active workstation.Results:A significant difference was found for DFTT, but no differences across conditions were found on ACTT or SCWT. Examination of the linear contrasts and post hoc means comparison tests revealed significant differences in DFTT scores between sitting and walking (t = 2.39 (49) P < .02) and standing and walking (t = 2.28 (49) P < .03). These results indicate that adding the walking task to the ACTT and SCWT conditions results in no decrement in performance on these tasks. Conversely, adding the walking task to the DFTT condition results in reduced performance on the DFTT task.Conclusions:These results further support the potential of active workstations to increase physical activity in the workplace without compromising cognitive capabilities.

Purine ring-opened 7-methylguanine, prepared in vitro by alkaline treatment of 7-methylguanosine or of methylated calf thymus DNA, was extensively characterized by chromatographic and spectral techniques as N5-methyl-N5-formyl-2,5,6-triamino-4-hydroxypyrimidine. This modified base chromatographed as an early-eluting peak on an ion-exchange column but separated into two interconvertible components after reversed-phase or porous-resin h.p.l.c. The two components were analyzed by thermal desorption mass spectrometry and 500 MHz 1H-n.m.r. spectroscopy. Their mass spectra were identical (M+ at m/z 183) and their n.m.r. spectra each exhibited the same two sets of resonances whose relative intensities were solvent-dependent. Analysis by h.p.l.c. showed interconversion of the two components and kinetic studies demonstrated that this reaction was a reversible first-order process. At equilibrium, k1 = k2 = 0.334 h-1 and delta G = 22.9 kcal/mol. These data indicated that the ring-opened 7-methylguanine exists as cis/trans isomers with restricted rotation about the amide bond. Treatment of rats with an intraurethral initiating dose of the carcinogen N-methylnitrosourea resulted in a high level of bladder epithelial DNA modification with 7-methylguanine, O6-methylguanine, and methyl phosphotriesters as major adducts at 2 h after instillation. Purine ring-opened 7-methylguanine, chromatographically identical to the in vitro products, was initially a minor adduct. However, it was the only persistent modification in the bladder epithelial DNA and eventually accounted for 72% of the total carcinogen binding after 21 days. A tumor-promoting regimen, involving dietary sodium saccharin, did not alter the repair or persistence of any of the methylated adducts. These data demonstrate that purine ring-opened 7-methylguanine, previously reported to exist in liver DNA after N,N-dimethylnitrosamine or 1,2-dimethylhydrazine treatment, is present in a carcinogen-target tissue and is considerably more persistent than O6-methylguanine or other DNA methylation products. The possible role of this adduct as a promutagenic lesion initiating urinary bladder carcinogenesis is discussed.

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