ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
Histology is the study of the microscopic structure of biological tissues. It is a subdiscipline of anatomy, and is also called microscopic anatomy. The typical cell types in the brain are NEURONS and glia. Neurons have a SOMA (cell body), dendrites (see DENDRITE) and an AXON. Glial cells, usually smaller than neurons, have a cell body and processes, but no axon. Glial cells are classified into ASTROGLIA, MICROGLIA and OLIGODENDROGLIA, each of which has a distinct MORPHOLOGY. These cells and their cellular elements can be studied with histological staining methods. Histological techniques are also used to examine pathological structures such as various types of TUMOUR, GLIOSIS and AMYLOID deposits in ALZHEIMER'S DEMENTIA. Most histological methods are applicable to all biological tissues, but certain staining methods are specifically developed for neural tissues which contain unique elements. The following summarizes the histological methods that are commonly used for neural tissues.
Experimental Methods in Cardiovascular Mechanics
Michel R. Labrosse in Cardiovascular Mechanics, 2018
Histology, the study of the microscopic anatomy of cells and tissues (Hillman 2000), has spawned many useful techniques since the second half of the nineteenth century (Table 4.1). These techniques have progressively combined with methods from physics and materials science such as electron microscopy, polarized light microscopy, Fourier-transform infrared spectroscopy, optical coherence tomography, confocal laser scanning microscopy, second harmonic generation, and two-photon excited fluorescence (Bergholt et al. 2016). However, these methods remain qualitative or semiquantitative in nature, and although they might, under the right circumstances, provide insight into the relative spatial distributions of the major constituents of the ECM, they are usually limited by the spatial resolution that they can achieve (Bergholt et al. 2016).
Histological Study in Orthopaedic Animal Research
Yuehuei H. An, Richard J. Friedman in Animal Models in Orthopaedic Research, 2020
Qualitative evaluation of histologic changes in bone and cartilage is usually the first level of evaluation of specimens from an orthopaedic experimental study. Initial qualitative studies are of value because they help focus the investigator on specific sampling sites of interest under the microscope and help to further refine the investigator’s notion of what type of quantitative information should be collected in the study. For large projects involving many investigators, this is also a useful first approach to the histologic study of the specimens of interest whereby teams of researchers discuss, evaluate and agree on the quantitative data to be collected. Qualitative studies are also of value should experimental treatment produce biochemical changes in matrices which can be revealed by special staining techniques. Histology in such research can play a valuable role prior to biochemical tissue analysis.
Pharmacokinetics, tissue distribution and safety of gold nanoparticle/PKC Delta inhibitor peptide hybrid in rats
Published in Nanotoxicology, 2020
Hisato Konoeda, Hiromitsu Takizawa, Annette Gower, Michael Zhao, Oyedele A. Adeyi, Mingyao Liu
For the toxicity study, we used both male (295–318 g 10–11 weeks old) and female (222–268 g, 10–11 weeks old) SD rats. Based on the results of the dose range testing, 12 rats of each sex were divided into three groups (n = 4 rats/group): control group (no treatment), therapeutic dose (7.5 pmol of GNP-50PKCi), and maximal dose (120 pmol/kg of GNP-50PKCi). One ml of normal saline (De Jong et al.), or drug in NS was intravenously administrated to each animal, under 3% isoflurane inhaled anesthesia. Animals were sacrificed one day after drug injection. Tissues were collected for histology assessment. Blood was collected for a complete blood count (Hemavet 950 FS, Drew Scientific Group, Miami Lakes, FL, USA) and blood biochemistry (Vetscan VS2, Abaxis, Union City, CA, USA) (Figure 5(A)). Collected organs, including heart, lung, liver, spleen, thymus, kidney, adrenal grand, muscle, skin, and injection site, were fixed in 10% buffered formalin for 24 hours and stored in 70% ethanol at 4 °C. Tissue samples were embedded in paraffin wax, cut into 4 μm sections, stained with hematoxylin and eosin (H&E) and examined by a pathologist for any abnormalities in the tissue.
Interleukin 7-expressing fibroblasts promote breast cancer growth through sustenance of tumor cell stemness
Published in OncoImmunology, 2018
Maximilian Boesch, Lucas Onder, Hung-Wei Cheng, Mario Novkovic, Urs Mörbe, Sieghart Sopper, Guenther Gastl, Wolfram Jochum, Thomas Ruhstaller, Michael Knauer, Burkhard Ludewig
Histology. Tumors and tdLNs (inguinal) were harvested and fixed overnight in 4% (w/v) paraformaldehyde (draining activity of the ipsilateral inguinal lymph node was demonstrated using in vivo tracking of intratumorally administered 40 kDa FITC-dextran; data not shown). Tissues were washed in PBS containing 1% (v/v) Triton-X 100 (Sigma-Aldrich) and 2% (v/v) FBS. Samples were embedded in 4% (w/v) low-meting agarose (Peqlab) and cut into 40 µm sections using a VT-1200 Vibratome (Leica Biosystems). Unspecific binding was reduced through blocking with 1 mg/ml anti-FcγR antibodies (BD Biosciences), and sections were incubated overnight with the following antibodies: anti-EYFP (Clontech), anti-PDPN (eBioscience), anti-αSMA (Sigma-Aldrich), anti-CD31 (BioLegend), and anti-Ki-67 (eBioscience). Primary antibodies were detected with the following secondary reagents: Alexa488-conjugated anti-rabbit-IgG, DyLight549-conjugated anti-Syrian hamster-IgG, and Alexa647-conjugated streptavidin (Jackson ImmunoResearch). tdT expression by tumor cells did not require antibody-mediated signal amplification for visualization. Nuclei were stained with DAPI (Life Technologies) and sections were mounted onto glass slides using specialized fluorescence medium (Dako). Samples were analyzed on an LSM-710 confocal microscope operated by ZEN 2010 software (Zeiss), and images were processed in Imaris version 7.7.1 (Bitplane).
Amyloid Beta Deposition Could Cause Corneal Epithelial Cell Degeneration Associated with Increasing Apoptosis in APPswePS1 Transgenic Mice
Published in Current Eye Research, 2018
Zhizhang Dong, Ali Luo, Yifeng Gan, Juan Li
Tissue histology was performed as described earlier.21,22 Each mouse was deeply anesthetized with an overdose of 4.3% chloral hydrate (0.1 ml/g) and was transcardially perfused with 30 mL of ice-cold 0.1 M phosphate-buffered saline (PBS), pH 7.4. The enucleated eyes were sectioned at the equator, while the anterior part, including the cornea, sclera, and conjunctiva, was examined. The corneas of each mouse were fixed in 4% paraformaldehyde (PFA) in PBS (pH7.4) overnight at room temperature (RT), and were dehydrated in a series of isopropanol concentration (70%, 90%, and 100%), and subsequently embedded in paraffin. The corneas were then subjected to histopathology. The eyes were serially sectioned through the center to a 4 μm thickness, and the sections were stained with Hematoxylin and Eosin (H&E) (Sigma, St. Louis, MO, USA) or were prepared for immunochemistry analysis. These sections were examined via light microscopy in which images were collected from areas approximately 300–500 μm away from the cornea center.