Some limitations of this study should be consideration. First, long term follow-up data are lacking. Further studies are needed to determine whether serum IGF-1 levels predicts long term outcomes after a stroke in our population. Second, serum IGF-1 levels were only measured once at admission, this study yielded no data regarding when and how long IGF-1 is elevated in these patients. Thus, additional measurements in the days after would have been of interest. Furthermore, biological effects and bioavailability of IGF-1 are modulated through IGFBPs, which control IGF-1 access to cell surface receptors. Unfortunately, we did not have IGFBPs available, and therefore our Procyanidin-B1 results do not fully represent biologically active IGF-1. Finally, data derived from a single-centre study always need to be replicated in larger multicentre studies. The interrogation of biological systems with secondary ion mass spectrometryhas seen significant growth over the last decade.This relatively newfound application of a surface technique traditionally limited to the study of inorganic and small molecule analytes is largely derived from the advent of larger, cluster primary ion probeswhich provide enhanced secondary ion yields of molecular and fragment ions from biological samples. While the use of traditional time of flightand magnetic sector based methodologies have intrinsic advantages for the in situ analysis of surfaces, the complexity and number of components usually encountered in the analysis of biological systems warrant the coupling of these new sources to high mass accuracy and resolution analytical devices for direct identification of the molecules of interest.In particular, this requirement grows out of the need for improved identification certainty for molecular ions generated from biological samples, which are substantially more complex relative to semiconductor and polymer-based applications, where the number of sample components is limited and the analyte of interest is typically predetermined. Previous mass spectrometry imaging studies have shown the advantages of correlating spatial information with molecular composition for the study of a variety of biological systems.A common drive has been the search for biological models and better interrogation probes with higher spatial resolution and improved molecular identification. To this end, we used Dictyostelium discoideum as a biological model for evaluating the performance of two different mass spectrometry imaging approaches. D. discoideum cells are eukaryotic cells that normally live on soil surfaces and eat bacteria.An interesting feature of their biological cycle is that when the cells overgrow their food supply and starve, they aggregate together in dendritic streams to form groups of,20,000 cells. The aggregated cells eventually form a fruiting body consisting of a 1�C2 mm tall stalk supporting a mass of spore cells which can then be dispersed by the wind to start new colonies. Gomisin-D Because soil surfaces are exposed to rain water, the cells can survive and undergo development in water. This feature makes D. discoideum a good model for in situ mass spectrometry imaging since it does not require the use of cleaning protocols that can potentially compromise the spatial information. In addition, this cell averages 10 mm in size, which is at the fron their distribution.