Agarose cell block: innovated technique for the processing of urine cytology for electron microscopy examination

ABSTRACT

Easy manipulation and preservation of cells in suspension through the different steps of sample processing for electron microscopy examination is essential for proper diagnosis. The present study used agarose gel as an embedding media for the processing of cell in suspension for electron microscopic examination. The study also modified the agarcyto cell block procedure for multiple molecular diagnostic analyses on a single scraping from uterine cervix of Kerstens et al.[2000] to convene with electron microscopic processing of exfoliated urothelial cell in voided urine or cell in suspension. The applied protocol depends on the embedding or coating of urothelial cells sediment with melted and then solidified 2% agarose in distilled water. This step is preceded by fixation of urine sediment in 4% buffered glutaraldehyde in sodium cacodylate. The solidified agarose cell block [ACB] is then divided longitudinally into two portion. One portion is fixed in formalin and processed for paraffin block preparation and the other half is divided into tiny pieces and refixed in 4% buffered glutaraldehyde then processed for EM examination. The advantage of this previously discussed maneuver is getting from the same sample, paraffin section stained with haematoxylin and eosin for light microscopic examination and utrathin section for EM examination. Moreover, different histo and immunohistostains can be applied on the paraffin prepared sections. In this work, twenty urine samples were processed using the conventional EM techniques and another twenty urine samples were processed using the innovated ACB technique. The later one allowed an optimal condition for cell processing. It minimized the loss of the harvested cells during the running procedure. It provided good support to the cells. Moreover, the damage imposed on cells by centrifugal forces during the conventional technique was avoided