Application of Electron Microscopes in Nanotoxicity Assessment.

In this chapter, we highlight the applications of electron microscopes (EMs) in nanotoxicity assessment. EMs can provide detailed information about the size and morphology of nanomaterials (NMs), their localization in cells and tissues, the nano-bio interactions, as well as the ultrastructural changes induced by NMs exposure. Here, we share with the readers how we prepare the tissue sample, and the different types of EMs used among the nanotoxicologists. It is possible to deploy conventional EMs along or in combination with other analytical techniques, such as electron energy loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS or EDX), and TEM-assisted scanning transmission X-ray microscopy (STXM), toward further elemental and chemical characterization. Appropriate images are inserted to illustrate throughout this chapter.

Native System and Cultured Cell Electrophysiology for Investigating Anesthetic Mechanisms.

Anesthetic agents interact with a variety of ion channels and membrane-bound receptors, often at agent-specific binding sites of a single protein. These molecular-level interactions are ultimately responsible for producing the clinically anesthetized state. Between these two scales of effect, anesthetic agents can be studied in terms of how they impact the physiology of neuronal circuits, individual neurons, and cells expressing individual receptor types. The acutely dissected hippocampal slice is one of the most extensively studied and characterized preparations of intact neural tissue and serves as a highly useful experimental model system to test hypotheses of anesthetic mechanisms. Specific agent-receptor interactions and their effect on excitable membranes can further be defined with molecular precision in cell-based expression systems. We highlight several approaches in these respective systems that we have used and that also have been used by many investigators worldwide. We emphasize economy and quality control, to allow an experimenter to carry out these types of studies in a rigorous and efficient manner.

Macroscopic Assessment and Cut Up of Endoscopic Resection Specimens for Early Esophageal Glandular Malignancies.

Pathological assessment of tissue is the gold standard for diagnosis and staging of neoplasia and provides key prognostic information for clinical management. Proper macroscopic assessment and cut-up technique is essential to ensure that the overall assessment is correct and reproducible. Endoscopic mucosal resection is a technique used for removing early neoplastic glandular lesions of the esophagus at the level of submucosa. Here, we describe the macroscopic assessment and dissection techniques used for the routine handling of endoscopic mucosal resection specimens in the clinical laboratory.

Quality control in diagnostic immunohistochemistry: integrated on-slide positive controls.

Standardization in immunohistochemistry is a priority in modern pathology and requires strict quality control. Cost containment has also become fundamental and auditing of all procedures must take into account both these principles. Positive controls must be routinely performed so that their positivity guarantees the appropriateness of the immunohistochemical procedure. The aim of this study is to develop a low cost (utilizing a punch biopsy-PB-tool) procedure to construct positive controls which can be integrated in the patient's tissue slide. Sixteen frequently used control blocks were selected and multiple cylindrical samples were obtained using a 5-mm diameter punch biopsy tool, separately re-embedding them in single blocks. For each diagnostic immunoreaction requiring a positive control, an integrated PB-control section (cut from the appropriate PB-control block) was added to the top right corner of the diagnostic slide before immunostaining. This integrated control technique permitted a saving of 4.75% in total direct lab costs and proved to be technically feasible and reliable. Our proposal is easy to perform and within the reach of all pathology labs, requires easily available tools, its application costs is less than using external paired controls and ensures that a specific control for each slide is always available.

Improvements in cell block processing: The Cell-Gel method.

BACKGROUND: The ability to produce adequate cell blocks profoundly impacts the diagnostic usefulness of cytology specimens. Cell blocks are routinely processed from fine-needle aspiration specimens or concentrated fluid samples. Obtaining directed passes for the sole purpose of producing a cell block is common practice, particularly when the cytopathologist anticipates the need for ancillary immunocytochemical stains and/or molecular studies. METHODS: The authors developed an effective and inexpensive process for producing cell blocks that consistently yields abundant cellular material, which they have termed the Cell-Gel method. This method can be simplified into 3 main steps: 1) preparing the sample; 2) constructing the cell block; and 3) processing the cell block. Highlights of the protocol include using a hemolytic fixative for sample preparation and disposable base molds for cell block construction. RESULTS: The cell block failure rate in the current study decreased from 18% with the HistoGel Tube method (January 2014-December 2014) to 6% with the Cell-Gel method (January 2015-December 2016). The authors evaluated 110 cell blocks processed with the HistoGel Tube method and 110 cell blocks processed with the Cell-Gel method, for a total evaluation of 220 cell blocks. CONCLUSIONS: The authors have developed an effective and inexpensive protocol for producing cell blocks that consistently yields abundant cellular material. The Cell-Gel method uses a hemolytic fixative and disposable base molds to produce adequate cell blocks. When the method was implemented, the cell block failure rate of the study laboratory decreased by approximately 67%. Cancer Cytopathol 2017;125:267-276. © 2016 American Cancer Society.