HISTOCHEICAL ALKYLATION: A STUDY OF METHYL IODIDE AND ITS EFFECT ON TISSUES

doi:10.1177/12.7.504

Paper

HISTOCHEICAL ALKYLATION: A STUDY OF METHYL IODIDE AND ITS EFFECT ON TISSUES

Published Jul 1, 1964 · J. Y. Terner

Journal of Histochemistry and Cytochemistry

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37

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Abstract

The use of methyl iodide as a histochemical alkylating agent is described. Methyl iodide selectively esterifies carbohydrate and other carboxyl groups. Sulfate half esters are not affected. Phosphate esters are esterified by methyl iodide, although the latter reaction is more variable; in several tissues nuclear basophilia could not be abolished. Saponification with barium hydroxide reverses the methyl iodide blockade of basophilia. Sulfhydryl and phenol reactions are prevented by methylation with methyl iodide; amines are alkylated and the usual blockade of acidophilia by acylation or deamination is prevented. Saponification does not reverse the blockade of these latter groups. The periodic acid-Schiff and Sakaguchi reactions are not affected. Marked increases in acidophilia were noted after methylation with methyl iodide. The hypothesis that a large number of tissue acids and amines are ordinarily prevented from binding basic and acid dyes respectively by intra- or intermolecular salt linkages is set forth. Similarly, the inability of protein end groups to demonstrate chemically determined pK values (to 2.5 for carboxyl groups and to 12.0 for arginine) in their interaction with dyes is attributed to interfering salt linkages.

Study Snapshot

Methyl iodide selectively esterifies carbohydrate and other carboxyl groups in tissues, preventing reactions and increasing acidophilia, potentially impacting dye binding and protein interaction.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

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Paper

HISTOCHEICAL ALKYLATION: A STUDY OF METHYL IODIDE AND ITS EFFECT ON TISSUES

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References

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Lactone formation in mucin metachromasia and basophilia is primarily driven by sialic acids, with pyridine-acetic blockade reversed by alkaline hydrolysis.

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This study identifies salivary mucins using a combination of chromatography and immunohistochemistry, revealing that salivary mucins are a complex mixture of proteins and lipids, with varying degrees of serine and mucin content.

AN IMPROVED SAKAGUCHI REACTION FOR MICROSPECTROPHOTOMETRIC USE

The modified Sakaguchi reaction allows for quantitative microspectrophotometric estimation of protein arginine, eliminating tissue damage and stabilizing the resulting color.

ALKYLATION OF AMINES: A STUDY OF METHYLATION AND ITS EFFECTS ON AMINES

Higher temperatures of methylation alkylate amines, preventing their oxidative destruction by chloramine T or nitrous acid without affecting their salt forming properties.

A CORRELATIVE STUDY OF THE HISTOCHEMICAL PROPERTIES OF RODENT ACID MUCOPOLYSACCHARIDES

Rodent acid mucopolysaccharides show diverse histochemical properties, with some sulfated and others nonsulfated, and mild treatment with acid methanol can restore reactivity and eliminate artificial azurophilia.

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The nitrosophenol-metal chelate method is a useful confirmatory technique for localizing protein-bound tyrosine in tissue sections, but its sensitivity is less than the diazotization-coupling reaction.

SAPONIFICATION AS A MEANS OF SELECTIVELY REVERSING THE METHYLATION BLOCKADE OF TISSUE BASOPHILIA

Saponification selectively reverses methylation blockade in tissue basophilia at pH 3-4, but not below, suggesting methylation hydrolyzes sulfate esters and esterifies other acid groupings in tissue sections.

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Acetylation and nitrification of tissue amino groups can be used to exclude amines as reactive groups in histochemistry, but a systematic study is needed for discrimination between primary, secondary, and tertiary amine groups.

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This study presents a highly specific, chromogenic, and permanent histochemical method for demonstrating indole derivatives in various tissues, with potential applications in tissue localization and tissue-specificity studies.

Citations

Does progressive nuclear staining with hemalum (alum hematoxylin) involve DNA, and what is the nature of the dye-chromatin complex?

Hemalum selectively stains DNA, not histone, in chromatin, with the red hemalum cation electrostatically attracted to the phosphate anion of DNA.

Quantitative analysis of spatial proteoglycan content in articular cartilage with Fourier transform infrared imaging spectroscopy: Critical evaluation of analysis methods and specificity of the parameters

FT-IRIS methods are specific and can accurately determine depthwise proteoglycan content in articular cartilage, but curve fitting can improve specificity.

Application of selected cationic dyes for the semiquantitative estimation of glycosaminoglycans in histological sections of articular cartilage by microspectrophotometry

Thionin and Safranin O are excellent cationic dyes for semiquantitative estimation of glycosaminoglycans in articular cartilage sections, with consistent stain distribution across sections.

Decreased birefringence of the superficial zone collagen network in the canine knee (stifle) articular cartilage after long distance running training, detected by quantitative polarised light microscopy.

Long-distance running in beagles leads to reduced superficial zone birefringence in articular cartilage, suggesting disorganisation or reorientation of the superficial zone collagen network.

The effect of histochemical methylation on the phosphate groups of nucleic acids: Interpretation of the absence of nuclear basophilia

Hot hydrochloric acid-methanol does not methylate nucleic acid diester phosphate groups, but instead causes a loss of nuclear basophilia due to excess positive charge on chromatin after methylation of protein carboxyl groups.

Elektronenmikroskopisch-cytochemische Untersuchungen an glycerinierter Flugmuskulatur vonLocusta migratoria L. Die Eisencolloidreaktion und Alcianblaubindung

Electron microscopy reveals that glycerinated locust flight muscle exhibits colloidial iron reactions and Alcian blue binding, which are eliminated by blocking reactions for acidic anionic groups but not hydrolytic enzymes.

The mechanism of metal binding to glutaraldehyde-fixed noradrenaline-storing adrenomedullary granules

Metal binding to glutaraldehyde-fixed noradrenaline granules depends on the presence of phenolic hydroxyl groups, with complex formation explaining the preservation of reducing properties.

Demonstration of orderly arranged acidic groups in amyloid by alcian blue

Alcian blue staining reveals oriented acid mucopolysaccharides in amyloid and cartilage, responsible for the red color in polarized light.