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Pneumocystis carinii
Published in Peter D. Walzer, Robert M. Genta, Parasitic Infections in the Compromised Host, 2020
Peter D. Walzer, C. Kurtis Kim, Melanie T. Cushion
At times, combinations of methenamine silver with other stains have been used to examine the interaction of P. carinii with host tissues. One example has been the use of hematoxylin-eosin counterstain to analyze the inflammatory cellular response. Periodic acid Schiff (PAS) and sodium bisulfite resorcinol stains have been used to identify basement membranes (302).
Routine and Special Techniques in Toxicologic Pathology
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Daniel J. Patrick, Matthew L. Renninger, Peter C. Mann
Periodic acid–Schiff (PAS) is a staining method most often used to identify the presence of glycogen in tissue sections. The periodic acid oxidizes glucose residues in tissue, creating aldehydes that then react with the Schiff reagent, creating a magenta color. A blue counterstain is often added to make interpretation easier. PAS is used to identify structures that have a high proportion of carbohydrate macromolecules (glycogen, glycoproteins, and proteoglycans) typically found in connective tissue, mucus, and basal laminate. PAS is often used to elucidate changes in basement membranes. It also selectively stains most protozoal organisms as well as many fungal organisms. The presence of glycogen can be confirmed by using diastase to remove the glycogen. A PAS with diastase slide (glycogen digested) will not show any magenta staining, while a PAS without diastase negative slide will show magenta staining. The PAS staining for glycogen will depend on preservation of glycogen in the organs as it is subject to leeching out into the normal fixatives.
Symptom flowcharts and testing guidelines
Published in Sarah Bekaert, Alison White, Integrated Contraceptive and Sexual Healthcare, 2018
Sarah Bekaert, Alison White, Kathy French, Kevin Miles
Following solvent treatment, only Gram-positive cells remain stained, possibly because of their thick cell wall, which is not permeable to solvent. After the staining procedure, cells are treated with a counterstain, e.g. a red acidic dye such as safranin or acid fuchsin, in order to make Gram-negative (decolourised) cells visible. Counterstained Gram-negative cells appear red, and Gram-positive cells remain blue. Although the cell walls of Gram-negative and Gram-positive bacteria are similar in chemical composition, the cell wall of Gram-negative bacteria has a thin layer between an outer lipid-containing cell envelope and the inner cell membrane. This means that within the staining process, the cell wall loses the crystal violet colour during the use of the alcohol in the decolourisation process and takes on the red stain at the end part of the staining process. The Gram-positive cell wall is much thicker, and retains the crystal violet stain even through the decolourisation process.
3D volume segmentation and reconstruction. Supervised image classification and automated quantification of superparamagnetic iron oxide nanoparticles in histology slides for safety assessment
Published in Nanotoxicology, 2021
Anna Bogdanska, Oliviero L. Gobbo, Yuri Volkov, Adriele Prina-Mello
Following the SPION biodistribution and pharmacokinetic study (Gobbo et al. 2015), the organs were fixed in 4% formalin and paraffin embedded. Samples from two animals per time point were used in this study. Four consecutive sections (5 µm thick) were collected at three levels. First section was stained with hematoxylin and eosin (H&E) stain for general toxicity studies (data not shown). The following two sections were stained with Perls’ Prussian blue (PPB) staining as detailed in previous publication with minor modifications (Edge et al. 2016a). Briefly, rehydrated sections were covered with equal parts of hydrochloric acid (HCL) and potassium ferrocyanide (K4[Fe(CN)6]·3H2O) for 20 min. Slides were washed in distilled water and counterstained with eosin for 5 min. Following incubation periods, slides were rinsed with distilled water before being dehydrated in a graded series of alcohol rinses. Slides were then cleared in two baths of xylene, sealed under coverslips with DPX mounting medium and examined under light microscope. To evaluate if any iron-positive staining is masked by the counterstain, third section was stained with PPB stain omitting eosin step in the outlined protocol (data not shown).
Evaluation of sodium orthovanadate as a radioprotective agent under total-body irradiation and partial-body irradiation conditions in mice
Published in International Journal of Radiation Biology, 2021
Yuichi Nishiyama, Akinori Morita, Bing Wang, Takuma Sakai, Dwi Ramadhani, Hidetoshi Satoh, Kaoru Tanaka, Megumi Sasatani, Shintaro Ochi, Masahide Tominaga, Hitoshi Ikushima, Junji Ueno, Mitsuru Nenoi, Shin Aoki
At 4 and 7 days post-irradiation, mice were intraperitoneally injected with 5-Bromo-2′-deoxyuridine (BrdU; 50 mg/kg; Sigma) 1 h prior to euthanasia. The excised ileum was washed with 10 mM phosphate-buffered saline, fixed in 10% formalin, and embedded in paraffin. Cross sections of intestinal tract (5 μm thick) were stained with hematoxylin-eosin (HE) to examine morphological change of intestinal epithelium. Cells incorporating BrdU in the intestinal crypts were detected immunohistochemically using the BrdU in situ detection kit (BD Biosciences, San Diego, CA, USA) according to the manufacturer's instructions. Hematoxylin was used as counterstain. Intestinal tissue images were photographed with a BZ-9000 microscope (Keyence, Osaka, Japan), and three observers counted a surviving crypt having 5 or more BrdU-positive cells using a BZ-X analyzer software (Keyence) (Saha et al. 2011). The percentage of surviving crypts relative to the mean crypt number in mice that had been treated with NS only was calculated from a minimum of 3 cross-sections in each mouse.
Identification of possible Lynch syndrome in endometrial carcinomas at a public hospital in South Africa
Published in Southern African Journal of Gynaecological Oncology, 2020
The four mismatch repair antibodies, namely MLH1 (Novocastra, UK), PMS2 (Novocastra, UK), MSH2 (Novocastra, UK) and MSH6 (Novocastra, UK), were used to stain 4 μm deparaffinised sections. A microtome was used to cut tissue sections from paraffin-embedded blocks. The tissue sections were then floated onto slides, which subsequently underwent drying overnight at 60°C. These four immunohistochemical stains had previously been optimised according to departmental standard operating procedure. Staining of tissue sections includes the treatment of primary antibody serum. Each of the tissue sections then underwent staining with the following antibodies: MLH1 (Clone ES05, 1:50), PMS2 (Clone MOR4G, 1:50), MSH2 (Clone 25D12, 1:50) and MSH6 (PU29, 1:50). A mouse linker resulted in increased expression of antigens. The sections were washed with Tris buffered saline (TBS) at pH 7.6. Immunohistochemistry was undertaken using an automated staining machine (DAKO Autostainer Link 48, Denmark). A ready-made solution, the EnVision™ FLEX target Retrieval Solution, High pH, was used for antigen retrieval. The chromogen used was 3,3′ diaminobenzidine hydrochloride solution (DAB, Sigma, USA), which produced a brown pigment. Meyer's haematoxylin was the counterstain used on tissue sections. Appropriate positive and negative control tissue sections were used.