Preservation and Processing of Intestinal Tissue for the Assessment of Histopathology.

The intestine is often examined histologically in connection with allergies and in search for pathological changes. To be able to examine the intestine histologically with a microscope, it must be sampled and processed correctly. For microscopic analysis, the samples have to be cut into thin sections, stained, and mounted on slides. Since it is not possible to cut fresh samples without damaging them, they must first be fixed. The most common method, which is described herein, is the fixation in formalin with subsequent embedding in paraffin and staining of the slides with hematoxylin and eosin (H&E). Hematoxylin solutions (in this case Mayer's hemalum solution) stain the acidic components of the cell, i.e., cell nuclei, blue. The staining with eosin gives a pink staining of cytoplasm. This chapter describes the method of processing intestinal tissue for paraffin-embedding, sectioning, and staining with H&E. Tissue processing can be done in tissue processing machines or manually. We describe the manual processing that is often used for smaller batches of samples.

Rapid tissue processing using a temperature-controlled collection device to preserve tumor biomarkers.

Precision tissue diagnostics rely on high quality input specimens so that assay results are not affected by artifact, but advances in collection and processing of tissue specimens have lagged behind innovations in diagnostic assay development. Therefore, we have designed and evaluated a novel surgical tissue collection device that maintains and monitors sample temperature and motion throughout transport so that the major preanalytical variable of tissue temperature can be controlled and measured. This device, in combination with an improved cold-hot tissue fixation protocol affords optimal biomarker preservation in less overall time, thereby simultaneously improving diagnostic quality and turnaround time. We collected 50 primary and metastatic liver tumors using a novel transport device. Tissue was fixed using a rapid cold-hot fixation protocol and immunohistochemical assays were used to assess the performance of the device, in comparison to control tissue preserved using standard clinical fixation protocol. Two pathologists evaluated the IHC studies in a blinded fashion to determine the immunophenotype of each tumor. The observed IHC staining intensities and the clinical impressions of the immunophenotypes did not differ between tissue collected with the novel device and control tissue, while improvements in processing time were achieved. The novel cold transport device and rapid fixation protocol can be successfully and safely combined and used to monitor specimen conditions, thus preserving the diagnostic utility of specimens and improving the overall turn-around time of the diagnostic process.

Multispectral Fluorescence Imaging Allows for Distinctive Topographic Assessment and Subclassification of Tumor-Infiltrating and Surrounding Immune Cells.

Histomorphology has significantly changed over the last decades due to technological achievements in immunohistochemistry (IHC) for the visualization of specific proteins and in molecular pathology, particularly in the field of in situ hybridization of small oligonucleotides and amplification of DNA and RNA amplicons. With an increased availability of suitable methods, the demands regarding the observer of histomorphological slides were the supply of complex quantitative data as well as more information about protein expression and cell-cell interactions in tissue sections. Advances in fluorescence-based multiplexed IHC techniques, such as multispectral imaging (MSI), allow the quantification of multiple proteins at the same tissue section. In histopathology, it is a well-known technique for over a decade yet harboring serious problems concerning quantitative preciseness and tissue autofluorescence of multicolor staining when using formalin-fixed, paraffin-embedded (FFPE) tissue specimen. In recent years, milestones in tissue preparation, fluorescent dyes, hardware imaging, and software analysis were achieved including automated tissue segmentation (e.g., tumor vs. stroma) as well as in cellular and subcellular multiparameter analysis.This chapter covers the role that MSI plays in anatomic pathology for the analysis of FFPE tissue sections, discusses the technical aspects of MSI, and provides a review of its application in the characterization of immune cell infiltrates and beyond regarding its prognostic and predictive value and its use for guidance of clinical decisions for immunotherapeutic strategies.

Health Technology Assessment: introducing a vacuum-based preservation system for biological materials in the anatomic pathology workflow.

INTRODUCTION: The objective of this work is to assess the implementation of a newly introduced medical equipment technology for the vacuum-based preservation of biological materials within an Anatomic Pathology service. METHODS: The approach selected for the analysis is the Health Technology Assessment (HTA ), a comprehensive evaluation method based on relevant scientific evidence and designed to support healthcare decision makers in purchasing, replacing or disposing of technologies. The analysis focused on specific domains such as Technology, Organization, Safety and Economy. RESULTS: The study proves that the use of such technology ensures the biological specimen to be suitably preserved (up to 72 hours), both reducing the amount of fixative being employed in the diagnostic process (30% to 55%) and resulting, in the particular context under examination, in savings of 93%. DISCUSSION: The HTA reported no significant drawbacks related to the use of the technology being examined. Nonetheless, the workflow for managing the transfer of biological materials from the Operating Room to the Anatomic Pathology department needs to be redefined - in terms of handling, processing, storage and disposal. Other elements concerned the monitoring of storage temperature, fresh tissue handling and especially fixative amount reduction, which positively impacts on the operators' safety with regard to chemical hazards.