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Effects of Food Processing, Storage, and Cooking on Nutrients in Plant-Based Foods
Published in Nicole M. Farmer, Andres Victor Ardisson Korat, Cooking for Health and Disease Prevention, 2022
Blanching is mild heat treatment used in most vegetables and cut fruits prior to freezing. Its main purpose is the inactivation of enzymes that cause flavor or texture degradation during frozen storage. Examples of these enzymes include polyphenol oxidase, responsible for the development of undesirable colors through enzymatic browning (text box 1), and lipoxygenase that promotes the production of peroxides, which are responsible for undesirable flavors and odors. Of note, peroxidase activity is used as a proxy for lipoxygenase activity as a maker of the effectiveness of blanching because the activity of the latter is difficult to assess.
Free Radicals and Antioxidants
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Glutathione peroxidases (GSHPx) are found both in the cytoplasm and extracellularly in almost every human tissue (22). The biochemical activity of glutathione peroxidase is to reduce free hydrogen peroxide (H2O2) to water (H2O) and to reduce lipid hydroperoxides to their corresponding alcohols. They protect the cell against oxidative injury caused by H2O2 and prevent the formation of hydroxyl radical (•OH) from H2O2 (21). GSHPx convert the oxidant H2O2 into water with the aid of its coenzyme glutathione (GSH). The last one is oxidized into glutathione disulfide (GS-SG) (21, 22, 87).
Section Pretreatment, Epitope Demasking, and Methods for Dealing with Unwanted Staining
Published in Lars-Inge Larsson, Immunocytochemistry: Theory and Practice, 2020
Apart from immunoglobulins, immune-complexes, and protein A, peroxidase also may bind unspecifically to tissue. Binding of HRP conjugates to tissue was observed by Minard and Cawley.44 These authors found that pretreatment of sections with free HRP, followed by application of the methanol-H2O2 method for blocking peroxidase activity (Chapter 3Section II.B.l.d), reduced the unspecific staining. Straus also found mannose-specific binding sites for HRP in paraformaldehyde-fixed frozen sections.58 This binding required Ca2+ ion and was suppressed by mannose or mannan. Moreover, purified glycoproteins competed with HRP for this binding to lectin-like sites in tissue.58 The easiest way to avoid this otherwise interesting reaction is to avoid use of Ca2+ in buffers for immunocytochemistry. Unfortunately, lectin-HRP-coupled approaches would need Ca2+ for binding and may therefore be troublesome. Pino has cautioned against using HRP-immunoglobulin (Fab) conjugates, incorporating cationic HRP, as these may bind by charge attraction to tissue.48 He recommends use of anionic HRP-Fab conjugates. One peroxidase type (lactoperoxidase) has been found to bind to tubulin and this has been turned to advantage for demonstrating tubulin by a lactoperoxidase-DAB procedure.59
The possible effect of lycopene in ameliorating experimentally induced ulcerative colitis in adult male albino rats (A histological, immunohistochemical, and ultrastructural study)
Published in Ultrastructural Pathology, 2023
Shaimaa Mostafa Kashef, Rania Ibrahim Yassien, Dalia El-Sayed El-Ghazouly
5 μm thick sections were utilized for immunohistochemical staining. 0.3% hydrogen peroxide was used to block endogenous peroxidase activity. Citrate buffer was used for antigen retrieval after the treatment of the sections in a microwave. The tissue sections were incubated overnight at room temperature with the following; monoclonal rabbit ZO-1 antibody (ab221546, 1:300, Abcam, United States)20 and anti-COX-2 antibody (bs-10411 R, BIOSS, China, 1:300 dilution).21 Streptavidin biotin complex detection method was used in second step for staining. Finally, the sections were stained with diaminobenzidine (DAB) solution (as chromogen) for 5–10 min, washed three times in PBS for 2 min each, and counterstained with Mayer hematoxylin. Negative control was applied by the same steps without adding the primary antibody. All slides were examined and photographed by a light microscope (Olympus, Japan) with a built-in camera in the Histology department, Faculty of Medicine, Menofia University, Egypt.
Levetiracetam treatment in an experimental model of sciatic nerve injury: A randomized controlled trial
Published in Neurological Research, 2023
Aydin Sinan Apaydin, Cansu Sahin, Sevil Cayli, Ercan Bal, Ceylan Bal, Fatma Gökcem Yildiz, Giyas Ayberk
The procedure for immunohistochemistry has been described elsewhere [20]. Serial sections were collected and treated in 10 mM citrate buffer. Endogenous peroxidase activity was quenched by 3% hydrogen peroxide. Sections were then incubated in a blocking serum. Subsequently, sections were incubated overnight with mouse monoclonal S100 (S1-61) (1:300, Santa Cruz, sc-53,438) in a humidified chamber. Sequential incubations with biotinylated polyvalent antibodies and peroxidase-labeled streptavidin were performed according to the manufacturer’s instructions (Millipore, DAB500). Bound peroxidase was developed with DAB Chromogen, and sections were counterstained with Mayer’s Hematoxylin. For controls, sections were treated with the appropriate isotype mouse IgG. The evaluation of the immunohistochemical labeling was performed using H-Score analyses as described previously [20]. The intensities of S100 immunoreactivities were semi-quantitatively evaluated using the intensity categories. In each slide, 5 randomly selected areas were evaluated under a light microscope (40X and 100X objective), and the percentage of the cells for each intensity within these areas was determined at different times by 2 investigators who were not informed about the type and source of the tissues. The average score of both observers was used.
Diagnostic and prognostic role of protein and ultrastructural alterations at cell–extracellular matrix junctions in neoplastic progression of human oral malignancy
Published in Ultrastructural Pathology, 2022
Harsh Nitin Dongre, Snehal Mahadik, Chetan Ahire, Pallavi Rane, Shilpi Sharma, Fatima Lukmani, Asawari Patil, Devendra Chaukar, Sudeep Gupta, Sharada Suhas Sawant
Deparaffinized and rehydrated serial paraffin sections were processed for antigen retrieval using microwave treatment in sodium-citrate buffer (pH 6.0). After inhibition of endogenous peroxidase activity, sections were incubated with pre-immune serum to block nonspecific binding. Further, sections were incubated for 1 hour at room temperature (RT) with primary antibodies: anti-Integrin β4, (1:150 dilution; Santa Cruz Biotechnology, Germany), anti-BP180, (1:150 dilution; Aviva Systems Biology, CA, USA), and anti-laminin-5 (1:200 dilution; Abcam, MA, USA). This was followed by incubating sections with secondary antibody provided in the Vectastain Universal Elite ABC kit (Vector Laboratories, CA, USA) for 1 hour at RT. The reaction was visualized using 3,3’-Diaminobenzidine (DAB, Sigma Aldrich, USA) wherein a brown precipitate indicated the presence of the target protein. IHC staining intensity score was quantified using IHC profiler plugin in ImageJ software, as described previously.17