Merck, O7505-5G, Orcein

General description
Orcein (Cl Natural Red 28) is a versatile dye known for its exceptional staining properties, particularly for elastic fibres and lamellae in histological samples. With an absorption maximum of 575 nm in an aqueous solution at pH 9.2 and an emission maximum of 585-590 nm, Orcein is widely used in histology and cytology for its ability to highlight connective tissue elements. The dye exhibits varied solubility depending on the batch and pH, ranging from practically insoluble to 2% soluble in water, and from 0.1% to 4% in ethanol.
Application
Certified for use in Darrow′s elastic fiber stain; Orcein method for hepatitis B surface antigen.
Orcein is suitable for various applications, including:

• Staining Elastic Fibers: Commonly used to stain elastic fibers and lamellae in tissue sections, facilitating the study of connective tissue architecture.
• Whole Mount and Cryosection Staining: Effective for staining whole mounts and cryosections, allowing for detailed visualization of tissue morphology.
• Quantification of Elastin: Utilized in quantifying elastin content in tissues, which is vital for understanding various pathological conditions.
• Fluorescent Staining: Employed for fluorescent staining of elastic fibres in epoxy resin sections, enhancing the detection of specific tissue components.
• Demonstration of Connective Tissue Elements: Used to visualize related connective tissue structures, including elaunin and oxytalan fibers.
• Chromosome Staining: Applied in the staining of chromosomes in plants and human sex chromatin, aiding in genetic and cytogenetic studies.
• Nuclear Staining: Serves as a nuclear stain for whole mount staining of embryos and assessing oocyte maturation, contributing to developmental biology research.
• In-Situ Hybridization: Recommended for determining stages of meiosis in plant meiocytes, enhancing genetic research capabilities.
• Hepatic Inclusions Demonstration: Useful in demonstrating hepatic inclusions, particularly hepatitis B antigen and copper-protein deposits, aiding in liver pathology studies.