#6669 ANALYSIS OF KIDNEY BIOPSIES AND URINE SEDIMENT USING SCANNING ELECTRON MICROSCOPY (SEM) AND ATOMIC FORCE MICROSCOPY (AFM)

Abstract Background and Aims The classification of renal diseases is dependent on the evaluation kidney biopsies using light microscopy techniques. Ultrastructural details (e.g. podocyte foot processes, amyloid fibrils, Fabri's intracellular inclusions) need transmission electron (TEM) which has high costs, requires specialized personnel time consuming. Therefore, alternative techniques are highly desirable. Here we report our experience with scanning (SEM) atomic force (AFM). Method Paraffin-embedded sections (3μm thick) were examined after dewaxing Jones-methenamine methane staining for type IV collagen fibers. Dried urine sediments prepared standard methods cytological analysis. Analysis was then performed (nGauge system) dried specimens Scanning Electron Microscopy (Zeiss) gold-spattering surface. Reference images obtained by microscopy. Results combination SEM thin paraffin allows observation ultrastructural in a very simple fast preparation. AFM even faster than SEM, as it does not require any preparation surface sample. An important advantage possibility to view sample at low magnification, makes easier identify location glomeruli. It thus possible switch from small magnifications (100x) extreme (10000x). Notably, interpretation knowledge artifacts induced inclusion. Specifically, structures cells containing lipids (for example foamy cells) appear empty. Chromatin also condensed nuclei around periphery nucleus spike whit large empty areas. recognition subsequent images. Podocyte pedicles fusion can be identified relatively easily AFM. Both add relevant sediment cells, epithelial isolated tubular cells. Also, casts show many features evident classical optical measure thickness basement membrane great precision both major limitation this approach limited pathologists these absence an atlas normal pathological kidney. Conclusion Considering affordable costs instruments samples their analysis, should considered valid TEM. methods, cheap obtain biopsies. We thank ANED AST support given research.