Films were developed and analysed densitometrically after calibration with plastic standards (H-Microscales, Amersham) using the Image Pro Plus v.5.1 image analysis system.
The plastic standards were calibrated to tissue standards prepared from homogenized brain tissue with known protein content in order to express binding site densities on fmol/mg protein as described earlier [ 54, 64].
The known radioactivity of the coexposed plastic standards was calibrated to brain homogenates with known protein concentration to allow transformation of gray values of the autoradiographs into total binding (femtomole per milligram protein), displayed within linearized images (Fig. 2 D ).
Other sections were incubated with 10 nM [H]-NAMH plus 500 μM of their corresponding antagonist for nonspecific binding values that proved to be similar to that of the background; subsequently an autoradiographic film (Hyperfilm; Amersham, Piscataway, NJ, USA) was apposed to dried sections and to slides containing plastic standards.
Monocyte-derived macrophages (MDM) were differentiated from monocytes on tissue culture plastic using standard protocols (Dockrell et al. 2001).
It is also hoped that this will contribute towards a general improvement in wider trading relationships with waste pickers by influencing plastic industry standards.
It's important to note that these sorts of machines aren't "new," but rather, adaptations of plastic industry standards for the home workshop environment.
The grey value images of the co-exposed plastic C standards were used to compute a calibration curve by non-linear, least-squares fitting, which defined the relationship between grey values and concentration of radioactivity.
The testing machine had been validated in our laboratory, as recommended by Turner and Burr [ 13], using plastics material standards, and had been used previously to assess the compressive strength of peripheral bone specimens [ 14].
At low concentrations (under 10 g.e)., results for assays prepared in standard plastic were reduced by about 50% compared to the low-retention plastic.
