Table 1. Enumeration of the number and location of immunogold particles observed by immune-electron microscopy in islet of Langerhans cells of rat pancreas. Results of indirect immunogold labeling with 1H6 and an IgG2b isotype control (MOPC-141; Sigma). Raw data of this experiment is available as Figure 6 online at: http://www.nanotomy.org/). Abbreviations: Exp = experiment; Mab = monoclonal antibody used; [c] = concentration of antibody used for staining in microgram/ml; n = number of cells analyzed; n gold/cell = average number of gold particles per cell; Het = number of gold particles present in heterochromatin; Eu = number of gold particles present in euchromatin; H/E ratio = number of gold particles present in heterochromatin relative to the number of gold particles present in euchromatin; mito = mitochondria; ER = endoplasmatic reticulum; ER cyto = cytoplasmic side of the ER; ER lumen = luminal side of the ER; ER C/L ratio = ratio of the number of gold particles present in the cytoplasmic versus the luminal side of the ER; ctr = isotype control antibody.