Characterisation framework development for the SIMPASS (Singapore IMPact ASSessment) methodology

Purpose  

Life cycle assessment (LCA) practitioners in Singapore currently rely on foreign life cycle impact assessment (LCIA) methodologies when conducting studies, despite the fact that foreign methodologies may not be relevant, adaptable and sensitive to Singapore's circumstances. As a result, work has been undertaken to develop the Singapore IMPact ASSessment (SIMPASS) methodology by adapting and modifying existing LCIA methodologies to suit the Singaporean context. It is envisioned that the use of SIMPASS will improve the accuracy of LCA studies conducted for industries operating in Singapore.     

The subcellular distribution and partial characterization of cholinesterase activities of canine platelets

The multiple cholinesterase activities in canine platelets have been investigated. Platelets were homogenized by rapid decompression under nitrogen, glass tube/Teflon pestle, and glycerol lysis techniques. Rapid decompression under nitrogen technique was found to be the most efficient and gentle method for cell disruption. Homogenates were subfractionated using sodium diatrizoate density gradients. Marker enzyme assays and pulse labeling experiments with 5-hydroxy[¹⁴C]tryptamine and [¹²⁵I]thrombin on prepared subcellular fractions confirmed that the soluble, plasma membrane and the granule-1 fractions were all in reasonably pure form. Furthermore, labeling of the plasma membrane with [¹²⁵I]thrombin is cited as the first successful attempt at attaining a significantly bound marker for this structure. Cholinesterase activity distributions measured in these fractions indicated that about 30% of the activity was present in the plasma membrane, 50% in granule-1 and 5% in soluble fractions. Kinetic data of cholinesterase activities obtained from intact platelets, plasma membrane preparations and platelet release supernatants indicated that they are strikingly similar.