The relevance of the histochemistry of colonic mucins based upon their PAS reactivity.
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Adenoma↗
Biomedical subjects
C F Culling
Publications and source records attributed to C F Culling.
Carbohydrate markers in the lower gastro-intestinal tract.
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Adenocarcinoma↗
Simple inexpensive apparatus for the rapid DEAE-cellulose chromatography of small quantities of glycoproteins.
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Animals↗
Spin-labelling of sialic acid in soluble and cell-surface glycoproteins.
A new, mild method is described for spin-labelling sialic acid residues in situ. The procedure involves the formation of C-1 sialamides and has been applied to a serum glycoprotein, a mucin, tissue sections from human colon, and erythrocyte membrane components. The selectivity of the method and its possible applicability to other types of labelling are discussed.
Colon↗
A histochemical comparison of the O-acylated sialic acids of the epithelial mucins in ulcerative colitis, Crohn's disease, and normal controls.
Two histochemical techniques, the PAT/KOH/PAS and the PBT/KOH/PAS, were used to investigate the side chain O-acyl substitution patterns of the sialic acids of the colonic epithelial mucins in cases of ulcerative colitis and Crohn's disease. In both diseases there was, as compared to normal, a reduction in the proportion of sialic acids O-acylated at C7C8, the reduction being greater in ulcerative colitis. Further, there appeared to be an association between the severity of the disease and the reduction in the staining of O-acylated sialic acids. This relationship was more marked in ulcerative colitis. In some cases of both diseases there was evidence for epithelial mucins containing predominantly C7-substituted sialic acids. This study has confirmed our previous conclusion that, in Crohn's disease of the terminal ileum, the disease is associated with an increase in the proportion of sialic acids bearing side chain substituents.
Colitis, Ulcerative↗
The histochemistry of colonic mucins.
This presentation could perhaps better be titled the histochemistry of colonic mucins, as based upon PAS reactivity, since it mainly concerns development of methods for the identification of the various patterns of o-acylation of sialic acid as measured by alteration in PAS staining.
Animals↗
A correlative chemical and histochemical study of the O-acetylated sialic acids of human colonic epithelial glycoproteins in formalin fixed paraffin embedded tissues.
Procedures are described for the isolation and identification of epithelial glycoproteins from formalin fixed, paraffin embedded specimens of human large intestine. The side chain O-acetylation patterns of the sialic acids of these glycoproteins were surprisingly similar to those of purified glycoproteins prepared from epithelial cells obtained from the same tissue before fixation. These results were consistent with those obtained by histochemical procedures performed on representative sections taken from the same tissue blocks. The methodology described permits a direct correlation of chemical and histochemical results obtained from the study of colonic epithelial glycoproteins of both normal and diseased tissues. It eliminates some of the difficulties associated with interpretation of the results by either discipline and may provide new information which would be unavailable by either chemistry or histochemistry alone.
Acetylation↗
A histochemical method for the identification of 9-O-acyl sialic acid. An investigation of bovine submaxillary gland and intestinal mucins.
Prolongation of the initial periodate oxidation step of the periodate-borohydride technique/potassium hydroxide/periodic acid-Schiff and periodic acid-Thionin Schiff/potassium hydroxide/periodic acid-Schiff sequences produced little or no change in the diagnostic staining for the potassium hydroxide/periodic acid-Schiff effect, exhibited by the colonic epithelial mucins of man and rat and the Brunner's gland mucin of rabbits. In contrast, there was a gradual, but clear decrease in the intensity of such staining of bovine submaxillary gland mucins. It was concluded that, in the intestinal mucins studied the potassium hydroxide/periodic acid-Schiff effect was due to sialic acids bearing O-acyl substitutents at positions C7 and/or C8 whereas in bovine submaxillary gland mucin the potassium hydroxide/periodic acid-Schiff effect is probably due, at least in part, to the presence of 9-O-acyl sialic acids. This investigation has led to the development of a technique which can be used to identify 9-O-acyl sialic acids.
Animals↗
The apparent failure of sodium borohydride reduction to block further PAS reactivity in rat epithelial mucins.
Sections of rat small intestine were oxidized with 1% periodic acid for periods of 1, 2, 5, 10 and 30 min and were subsequently either (a) stained with Schiff reagent, or (b) reduced with sodium borohydride and then treated with either Schiff reagent alone or by the standard PAS procedure. It was found that whereas sodium borohydride reduction abolished all Schiff staining, initial periods of oxidation in excess of 10 min were necessary to abolish any subsequent PAS reactivity. The theoretical and practical significance of these data is discussed in relation to the recent publication of Bayliss & Adams (1976).
Animals↗
A new histochemical technique of use in the interpretation and diagnosis of adenocarcinoma and villous lesions in the large intestine.
The periodic acid-thionin Schiff/potassium hydroxide/periodic acid-Schiff (PAT/KOH/PAS) procedure has been used to investigate the histochemical staining characteristics of the mucins found in adenocarcinoma and villous lesions of the large intestine. The 46 blocks examined represented 58 lesions from 37 patients, all of whom had had resections for carcinoma of the colon. tin sharp contrast to normal colon, none of the adenocarcinomas stained red with the PAT/KOH/PAS. With two exceptions the poorly and moderately differentiated adenocarcinomas stained blue, whereas of the well differentiated lesions half were blue and half purple. The malignant villous lesions demonstrated the same trends, although a larger percentage were purple. None of the benign lesions stained blue. It is suggested that malignancy in the colon is accompanied by an increase in blue staining in the PAT/KOH/PAS technique and that such staining may be of value in the interpretation of highly atypical adenoma where it might identify the onset of malignancy. This change in staining indicates a distinct alteration in the chemistry of the mucins which we interpret as a reduction in the degree of side chain O-acylation of their constituent sialic acids.
Adenocarcinoma↗
Histochemical comparison of the epithelial mucins in the ileum in Crohn's disease and in normal controls.
A comparison of routine and special histochemical methods that were applied to the epithelial mucins of small intestine from patients with Crohn's disease and from normal controls showed that the normal small intestine (ileum) goblet cells secrete a predominantly non-sulphated sialomucin and that, in contradistinction to the colon, the neuraminidase insensitivity of the sialic acids of the small intestine was not due to either O-acylation at C4 or an ester substituent at C1. Presumably this implies that the protection against enzyme attack afforded to the mucosa by the mucin coat in the small intestine utilises a different mechanism from that in the colon and that, although in many respects the small intestinal mucins in Crohn's disease, and in normal controls are similar, there is an increase in side-chain O-acylated sialic acids in such mucins in Crohn's disease. This difference has not been described before, probably because it can be seen only after staining such sections by the PAT/KOH/PAS and the PBT/KOH/PAS techniques.
Crohn Disease↗
A simple method for the determination of the O-acetyl substitution pattern of the sialic acids of colonic epithelial glycoprotein.
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Acetates↗
A method for the simultaneous estimation of free and ketosidically bound sialic acids.
Various methods for the estimation of free and ketosidically bound sialic acid were investigated for accuracy and specificity. It was found that oxidation with 0.025 M sodium metaperiodate in pH 7.0 phosphate buffer at room temperature for 20 min provided a simple, rapid, sensitive method whereby both the free and the ketosidically bound acid present in a mixture could be quantitatively analyzed. On completion of the oxidation step, the bound sialic acid is estimated with resorcinol reagent and the free sialic acid with thiobarbituric acid reagent. Oxidation under these conditions permitted a facile analysis of mixtures of bovine submaxillary mucin and free N-acetylneuraminic acid, whereas the Warren thiobarbituric acid procedure gave an erroneous value for free sialic acid.
Animals↗
The use of a transesterification technique to distinguish between certain neuraminidase resistant epithelial mucins.
The effects of potassium hydroxide and soidum methoxide treatments upon the Alcian blue staining and neuraminidase lability of certain neuraminidase resistant epithelial mucins have been studied. The results were interpreted as indicating that while the mucins of rat colon and rabbit Brunner's gland contain only 4-0-acetyl sialic acid, human colonic epithelial mucins may contain some sialic acid with esters at the C1 carboxyl group.
Animals↗
A new histochemical method for the identification and visualization of both side chain acylated and nonacylated sialic acids.
A new histochemical method is described for the differentiation of mucins that utilizes two different Schiff reagents and allows single section identification of side chain O-acylated, and nonacylated, sialic acids in contrasting colors. In the event of mucins containing only one type of sialic acid, it may allow their specific identification (e.g., C7 or C8 side chain O-acylated). It has been shown to be useful in the identification of some metastases from adenocarcinomas of colon (where the primary is potassium hydroxide/periodic acid-Schiff positive) and should prove of great value in the investigation of diseases of the gastrointestinal tract and particularly those of the colon. It should also be valuable in the general field of epithelial mucin histochemistry, particularly for those mucins of the salivary and parotid glands, etc.
Animals↗
A histochemical method of differentiating lower gastrointestinal tract mucin from other mucins in primary or metastatic tumours.
Epithelial mucins of the normal terminal ileum, caecum, colon, and rectum of man are unique in that they alone exhibit staining following the periodate-borohydride/KOH/PAS technique. Application of this technique enables one to differentiate those mucin-producting metastases arising from adenocarcinoma of the lower gastrointestinal tract from those arising elsewhere, and may occasionally be useful in determining the site of the primary tumour when it is in doubt. Furthermore, it was found to be especially useful in distinguishing between primary adenocarcinoma of the lung and metastases in the lung from adenocarcinoma of the lower gastrointestinal tract.
Adenocarcinoma↗
The demonstration of O-acetylated sialic acids in colonic epithelial glycoproteins.
Glycoproteins have been isolated from a 1 M sodium chloride extract of the colonic epithelial cells of man and rat by a combination of Agarose gel and DEAE-cellulose chromatography; The glycoproteins contain O-acetylated or O-esterified sialic acids of at least four types: (a) unsubstituted or possible at position C-9, (b) substituted at C-4 and possibly at C-9, (c) substituted at C-7 and/or C-8, and (d) substituted at C-4 as well as at C-7 and/or C-8.
Animals↗
Differences in chemical composition between the epithelial glycoproteins of the upper and lower halves of rat colon.
Analysis of the apparently homogeneous sulfated sialoglycoproteins isolated from the epithelial cells of the upper (proximal to the ileum) and lower (proximal to the rectum) halves of Wistar rat colon showed that whereas they were similar in overall carbohydrate and amino acid composition, they differed significantly in the O-acetyl substitution pattern of their constituent sialic acids. The glycoprotein from the upper half of the colon was found to contain a larger percentage of sialic acid substitued at C7 and/or C8, as well as at C4 and C7 and/or C8; it contained less sialic acid which was unsubstituted as well as less subsituted at C4 alone. It has been shown that differences in substitution at C7 and/or C8 can be detected by analysis of the 105 000 g supernatants prepared from homogenates of isolated epithelial cells or fresh or formol calcium fixed whole colonic tissue.
Animals↗