Changes in composition of mucin in the mucosa adjacent to carcinoma of the colon as compared with the normal: a biochemical investigation

The quest for targeted delivery in colon cancer: mucoadhesive valdecoxib microspheres

The aim of the present study was to prepare valdecoxib, a cyclo-oxygenase-2 enzyme inhibitor, as a loaded multiparticulate system to achieve site-specific drug delivery to colorectal tumors. Film coating was done with the pH-sensitive polymer Eudragit S100 and sodium alginate was used as mucoadhesive polymer in the core. The microspheres were characterized by X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy and were evaluated for particle size, drug load, in vitro drug release, release kinetics, accelerated stability, and extent of mucoadhesion. The coated microspheres released the drug at pH 7.4, the putative parameter for colonic delivery. When applied to the mucosal surface of freshly excised goat colon, microspheres pretreated with phosphate buffer pH 7.4 for 30 minutes showed mucoadhesion. To ascertain the effect of valdecoxib on the viability of Caco-2 cells, the 3-(4,5-dimethylthiazol-2yl) 2,5-diphenyltetrazolium bromide) test was conducted using both valdecoxib and coated microspheres. In both cases, the percentage of dehydrogenase activity indicated a lack of toxicity against Caco-2 cells in the tested concentration range. Drug transport studies of the drug as well as the coated microspheres in buffers of pH 6 and 7.4 across Caco-2 cell monolayers were conducted. The microspheres were found to exhibit slower and delayed drug release and lower intracellular concentration of valdecoxib.

Distinct changes of dendritic cell number and IL-12 mRNA level in adjacent mucosa throughout the colorectal adenoma-carcinoma sequence

Adjacent mucosa may reflect the conflicting of host factors in response to the establishment or invasion of cancers. Characterization of anti-tumor immunity in this region may add help in understanding the immune-related mechanisms of colorectal carcinoma (CRC). In this study, adjacent non-tumor mucosa from 36 patients with colorectal adenoma (CRA), 26 with CRC and normal mucosa from 15 health controls were included, immune cell populations of dendritic cell, lymphocyte and macrophage were characterized with immunohistochemistry (IHC) and tissue messenger RNA (mRNA) levels of Th1 cytokines interferon (IFN)-gamma and its upstream inducers interleukin (IL)-12 and IL-18 were quantified with real-time PCR; In addition, dendritic cell differentiation and function inhibitors cyclooxygenase-2 (COX-2) and IL-6 mRNA levels were also quantified. By IHC, a significant decreased dendritic cell density in the non-tumor mucosa adjacent to CRC was detected (P < 0.05) as compared to the normal controls or adjacent mucosa of CRA. The grading scores for lymphocyte number in the adjacent mucosa of CRA and CRC were gradually non-statistically increased, while the grading scores for macrophages number was not changed. By quantitative real-time PCR, distinct local cytokine gene expression profile was demonstrated. In which, the Th1 cytokines, particularly IL-12, were increased in adjacent mucosa of CRA, but all significantly decreased in adjacent mucosa of CRC. In addition, the mRNA levels of IL-6 and COX-2 were significantly higher in adjacent mucosa of CRC than that in adjacent mucosa of CRA (both P < 0.05). Therefore, dendritic cell functional changes could be one of the important mechanisms for altered anti-tumour immunity in the adjacent non-tumor mucosa throughout adenoma-carcinoma sequence. The increased COX-2 and IL-6 might contribute to dendritic cell functional defect in adjacent mucosa of CRC.

Frequent p53 mutation in brain (fetal)-type glycogen phosphorylase positive foci adjacent to human 'de novo' colorectal carcinomas

'de novo' carcinogenesis has been advocated besides 'adenoma carcinoma sequence' as another dominant pathway leading to colorectal carcinoma. Our recent study has demonstrated that the distribution of brain (fetal)-type glycogen phosphorylase (BGP) positive foci (BGP foci) has a close relationship with the location of 'de novo' carcinoma. The aims of the present study are to investigate genetic alteration in the BGP foci and to characterize them in the 'de novo' carcinogenesis. 17 colorectal carcinomas without any adenoma component expressing both immunoreactive p53 and BGP protein were selected from 96 resected specimens from our previous study. Further investigations to examine the proliferating cell nuclear antigen (PCNA)-labelling index, and the p53 and the codon 12 of K-ras mutation using the polymerase chain reaction-single strand conformation polymorphism were performed in the BGP foci, BGP negative mucosa and carcinoma. The BGP foci were observed sporadically in the transitional mucosa adjacent to the carcinoma in all cases. The PCNA labelling index in the BGP foci was significantly higher than that in the BGP negative mucosa (P< 0.001). p53 mutations were observed in 8 carcinomas, but no K-ras mutation was detected. Interestingly, although none of the overexpressions of p53 protein was detected immunohistochemically in the BGP positive foci, the p53 gene frequently (41.2% of the BGP foci tested) mutated in spite of no K-ras mutation. The present study demonstrates potentially premalignant foci in the colorectal transitional mucosa with frequent p53 gene mutation. It is suggested that BGP foci are promising candidates for the further investigation of 'de novo' colorectal carcinogenesis.

Induction of angiogenesis by hyperplastic colonic mucosa adjacent to colon cancer

We determined whether hyperplastic mucosa adjacent to colon cancer contributes to neoplastic angiogenesis. Surgical specimens of human colon cancer (40 Dukes' stage B and 34 Dukes' stage C) were analyzed by immunohistochemistry for expression of proliferative and angiogenic molecules. The mucosa adjacent to Dukes' stage C tumors (but not Dukes' stage B tumors) had a higher Ki-67 labeling index and a higher expression of epidermal growth factor receptor and transforming growth factor-alpha than distant mucosa. The expression levels of vascular endothelial growth factor, basic fibroblast growth factor, interleukin-8, and the vascular density in the adjacent mucosa were similar to those in the tumor lesions and significantly higher than those in the distant mucosa. The expression of interferon-beta inversely correlated with the level of pro-angiogenic molecules and the vascular density. The injection of metastatic human colon cancer cells and murine colon cancer cells into the cecal wall of mice induced hyperplastic changes in the adjacent mucosa which expressed higher levels of epidermal growth factor receptor, basic fibroblast growth factor, and vascular endothelial growth factor, and lower levels of interferon-beta than did the control mucosa, which directly correlated with the degree of hyperplasia. These data suggest that metastatic human colon cancer cells can induce hyperplasia in the adjacent mucosa, which in turn produces angiogenic molecules that contribute to neoplastic angiogenesis.

Experimental models of colorectal cancer

PURPOSE

A review of in vivo and in vitro models of colorectal cancer is presented.

METHODS

A retrospective literature review was performed with reference to CD-ROM Medline and Index Medicus.

RESULTS

A comparison of the advantages and disadvantages of the models is presented in addition to a summary of individual model methodology and applications.

CONCLUSIONS

Such models are a useful adjunct for surgical research in colorectal oncology.

Histochemical analysis of sialomucin in Paget cells of mammary and extramammary Paget's disease

The cytoplasmic sialomucin in Paget cells of both mammary and extramammary Paget's diseases was examined, using a new method proposed by Volz et al. (1987a, b). The staining methods used involved an electrolyte-Alcian Blue (pH = 5.8) and periodic acid Schiff. Oxidation was performed with 0.4 mmol/l periodate in 1 mol/l HCl at 4 degrees C or 50 mmol/l periodate in distilled water at room temperature for 1 h. Methylation, saponification, borohydride reduction, and digestion with diastase, neuraminidase (Vibrio cholerae) or chondroitinase ABC, were also employed. The cytoplasmic mucin was found to exhibit positive reaction for the above staining which were variously altered by the chemical modification procedures and diminished in intensity or abolished by digestion with neuraminidase. These results suggest that the cytoplasmic mucin in Paget cells is sialomucin without side-chain substituent in genital Paget's disease, and that with a substituent at C7 in mammary Paget's disease.

Intestinal brush-border-associated enzymes: Co-ordinated expression in colorectal cancer

The brush border of normal small-intestine epithelial cells is rich in enzymes that are involved in the digestive process. Such molecules can be used as markers to analyze cell lineages and differentiation properties of colorectal cancers. Monoclonal antibodies detecting dipeptidyl peptidase-IV, aminopeptidase N, endopeptidase F, sucrase-isomaltase, alkaline phosphatase, maltase-glucoamylase and lactase have been used to analyze the phenotype of colorectal cancers, adjacent mucosa and histologically normal distant mucosa. The avidin-biotin peroxidase complex method was used. Expression of dipeptidyl peptidase-IV, aminopeptidase N, sucrase-isomaltase and alkaline phosphatase was common in non-neoplastic mucosa adjacent to, and distant from, the tumor; in contrast, endopeptidase F, maltase-glucoamylase and lactase were rarely expressed in normal distant mucosa and more frequently expressed in mucosa adjacent to the tumor. Dipeptidyl peptidase-IV, aminopeptidase N, endopeptidase F, sucrase-isomaltase and alkaline phosphatase were frequently expressed in colorectal cancers, whereas maltase-glucoamylase and lactase were rarely expressed. Two general patterns of antibody reactivity were observed: diffuse cytoplasmic and apical; apical reactivity was generally associated with more differentiated tumors. A logistic predictive regression model indicated that enzyme expression in colorectal cancers followed a coordinate pattern, but was unrelated to the location of the tumor, Dukes stage or differentiation grade. In conclusion, expression of brush-border-associated enzymes occurs frequently in colorectal cancers and is regulated in a co-ordinated manner. These markers can be used for the phenotypic sub-classification of colorectal cancers.

Expression of TAG-72 in normal colon, transitional mucosa, and colon cancer

Monoclonal antibody (MAb) B72.3 detects an epitope carried by high-molecular-weight mucins (tumor-associated glycoprotein, TAG-72) recently identified as sialyl-Tn. B72.3 MAb has a restricted pattern of reactivity with normal tissues but it reacts with a high proportion of epithelial cancers. To determine the possible relationship between neoplastic transformation and reactivity with B72.3 MAb, we have analyzed samples of normal colon, colon cancer and transitional mucosa (mucosa adjacent to colorectal cancer) or reactive mucosa (mucosa adjacent to squamous carcinoma of the anal canal, or mucosa overlying lymphoma). B72.3 MAb reacted strongly with 21/21 specimens of transitional mucosa and with 17/21 specimens of adjacent colon cancer. Reactivity of B72.3 MAb with transitional mucosa was strong and homogeneous, whereas reactivity with cancer tissue was weaker and more heterogeneous. Reactive mucosa adjacent to squamous carcinoma or lymphoma was also reactive with B72.3 MAb. Our findings show that, in the colon, expression of TAG-72 antigen occurs during the process of epithelial cell transformation but is also regulated by factors unrelated to the process of carcinogenesis.

Lectin histochemistry of adenomatous polyps. Not a predictor of metachronous lesions

The binding characteristics of fluorescein isothiocyanate conjugated lectins to normal colonic mucosa, and 43 adenomatous polyps were studied by fluorescence microscopy. The lectin, Dolichos biflorus agglutinin (DBA) stained intensely to upper crypt cells of the sigmoid colon and rectum but to a lesser degree to proximal colonic crypts or lower crypt cells distally. Peanut agglutinin (PNA) and Ulex europaeus agglutinin (UEA) did not bind to the theca of proximal or distal colonic crypts. The lectin Griffonia simplicafolia agglutinin (GSA1) bound intensely to upper and lower crypt cells of both regions. PNA binding was noted in 56% of adenomatous polyps, occurred more often in polyps of the distal colorectum, and increased with polyp size and villous histology. UEA bound to 26% of adenomatous polyps, 42% of proximal polyps, and 17% of distal polyps. DBA staining was noted in 72% of polyps without regional preference. GSA1 stained all polyp specimens. To determine if the lectin binding characteristics of an index (initial) polyp might serve as a predictor of metachronous lesions, 20 patients (29 polyps) without a history of polyps or cancer and who had at least one surveillance colonoscopy 1 to 3 years after the initial polypectomy were studied. The presence or absence of PNA, UEA, or DBA binding in an index polyp did not predict the occurrence of metachronous lesions. Five of the six patients with more than one index polyp had metachronous polyps at follow-up surveillance colonoscopy.

A morphometric assessment of transitional mucosa in the colon

Quantitative morphometric analysis was used in 10 resection specimens to assess so-called transitional mucosa immediately adjacent to colorectal carcinoma. Eleven nuclear and cellular variables were measured from the malignant epithelial area and from zones of increasing distance (1 cm) from the lesion. In addition, mean mucosal height was assessed for each zone. Morphometrical differences between the mucosa immediately adjacent to the malignant epithelium and that taken at some distance from it were determined by Mann-Whitney U tests. Transitional mucosa showed increased mucosal height but no nuclear differences from normal mucosa. Other work has shown that there are nuclear morphometric differences associated with premalignant conditions in the colon. Thus, the suggestion that transitional mucosa represents early neoplastic change cannot be supported.

Mucin abnormality of colonic mucosa in ulcerative colitis associated with carcinoma and/or dysplasia

Twenty cases of resected specimens of carcinoma and/or dysplasia complicating ulcerative colitis were histochemically investigated by the periodic acid-thionein Schiff/potassium hydroxide/periodic acid-Schiff (PAT/KOH/PAS) staining method to see mucin characteristics of carcinoma, dysplasia, and the background mucosa of these lesions. As a control, 11 resected specimens of ulcerative colitis without dysplastic changes and 26 specimens of colonic carcinoma were examined also. All dysplasia and carcinoma in ulcerative colitis stained blue, whereas normal colonic mucin stained red in 65 percent. In 14 of 20 specimens with carcinoma and/or dysplasia, the background mucosa appeared normal with hematoxylin and eosin staining, but showed a mosaic staining pattern with PAT/KOH/PAS. However, only two of 11 specimens of ulcerative colitis without dysplasia and none of 26 specimens of flat mucosa with colorectal carcinoma showed a mosaic staining pattern. From these observations it was concluded that the PAT/KOH/PAS staining method could be useful as a histochemical marker of premalignant change in longstanding ulcerative colitis.

Changes in the lectin-binding pattern of PNA-agglutinin and UEA1 during the DMH-induced carcinogenesis in the normal appearing colonic mucosa of the rat

The purpose of this study was the investigation of changes in the lectin-binding pattern prior to tumour formation in an experimental model. Female Wistar rats were treated with 1,2-dimethylhydrazine (DMH). After 4, 8, 16, 24, 32 and 40 weeks of treatment the lectin-binding-pattern of the colonic mucosa appearing morphologically normal was examined at the caecum, proximal colon, distal colon and rectum, using FITC-conjugated Peanut-agglutinin (PNA) and Ulex europaeus-agglutinin1 (UEA1). In contradistinction to what has been reported earlier by other authors, PNA did not indicate constant cancer-associated mucin changes. In addition, there was no difference in the UEA1-binding between the control animals and the DMH-treated rats. Thus, in the rat there is no specific PNA- and UEA1-binding pattern during tumour induction in the gut.

Efficacy of differential mucin staining for predicting synchronous and metachronous colorectal carcinomas

Despite the controversy regarding the significance and usefulness of histochemically differential mucin staining as a marker for colorectal neoplasms, some investigators have used this technique to help define those persons at risk for development of recurrent colorectal carcinoma. To further evaluate the efficacy of this method, we reviewed 85 surgical specimens of the colon and rectum using a high iron diamine-alcian blue staining technique. The group studied included 73 patients with synchronous or metachronous carcinomas and adenomas and 12 patients with no recurrence for more than 5 years who had undergone adequate follow-up, including physical examination; evaluation of serum chemistry findings; and colonoscopy, barium enema, or both. Evaluation of Dukes' staging (A and B1 versus B2 and C2) and distance of the resection margins from the tumor (less than 5 cm versus 5 cm or more) showed no correlation with the amount of sialomucin present. Resection margins from patients with either synchronous or metachronous carcinomas had significantly higher sialomucin ratios than the group without recurrence, whereas those with synchronous or metachronous adenomas did not. The false-negative rate was 4 percent (1 of 23 specimens) and the false-positive rate, 42 percent (5 of 12 specimens). We conclude that this method for evaluating resection margins of colorectal cancer specimens with differential mucin staining is highly reliable for predicting the population with synchronous and metachronous colorectal carcinomas.

Glycoprotein abnormalities in colonic carcinomata, adenomata, and hyperplastic polyps shown by lectin peroxidase histochemistry

A technique for lectin-peroxidase histochemistry was adapted for the study of formalin fixed paraffin embedded colonic tissue. Ten lectins with differing carbohydrate binding specificity were tested against 20 normal rectal biopsy specimens and tissue from 19 colonic carcinomata, 19 tubular or tubulovillous adenomata, and 19 hyperplastic polyps. None of the normal rectal biopsy specimens bound the lectins peanut agglutinin (PNA), Griffonia simplicifolia II (GSII), and Ulex europaeus I (UEAI), whereas 18 carcinomata, 12 adenomata, and 18 hyperplastic polyps showed affinity for one or more of these lectins. Hyperplastic colonic polyps are shown to possess similar abnormalities in glycoprotein structure to malignant and adenomatous colonic tissue. This may simply indicate a non-specific reaction to changed rates of cell proliferation but might represent a more fundamental association between hyperplastic polyps and adenocarcinomas.

A scanning electron microscopy study of changes in rat colonic mucosa during carcinogenesis

Scanning electron microscopy (SEM) has been used to examine morphological changes on the colonic mucosal surface during experimental carcinogenesis. Seventy-five rats were given weekly injections of dimethylhydrazine (DMH) and 25 rats acted as controls. Groups of DMH-treated and control rats were sacrificed at regular intervals and specimens of their colons were examined by SEM. The normal colonic mucosa had an orderly architectural pattern which remained constant throughout the experiment. Abnormalities in the mucosa of treated rats were detected as early as 6 weeks after the first injection of DMH and thereafter there was progressive distortion of the crypts, development of pericryptal fissures and mucosal surface irregularities, and eventually, formation of focal protuberances, polyps, and tumors. The findings indicate that there is a definite pattern of progressive mucosal abnormalities commencing long before the development of focal colon tumors and that SEM is useful in the detection of these abnormalities.

Effect of steel wire sutures on the incidence of chemically induced rodent colonic tumours

An experiment is presented which shows that colonic primary tumours cluster around a previously constructed anastomosis and that the choice of suture materials (but not the technique of their insertion) can influence this. In a rodent model where dimethylhydrazine was administered 2 months after surgery, anastomotic tumours were most often seen when wire sutures--as used in the staples of anastomotic stapling guns--had been employed (10 out of 16 large bowel tumours were anastomotic as compared with 2 of 12 in a silk sutured group, P = 0.019). An explanation may be that wire sutures persist much longer than silk (in the experiment, 10 months after insertion, 4 per cent of silk sutures were still present, 15 per cent of wire, P less than 0.01). This was translated into a greater degree of scarring at the anastomosis, being most severe in the presence of persisting sutures. Of the 12 anastomotic tumours found in both groups, 7 (58 per cent) were in the minority (17-26 per cent) who had persisting sutures and the remaining 5 in the 47 who had none. Techniques of suturing (needle always passed from the serosa in; needle from mucosa out--the latter in such a way that mucosal cells could be displaced into the bowel wall where it was supposed that they might be more susceptible to subsequent carcinogenesis) did not affect tumour yield. We suggest that non-absorbable sutures, and especially stainless steel wire, should not be used when constructing an anastomosis after large bowel cancer surgery.

Histochemical demonstration of desialation and desulphation of normal and inflammatory bowel disease rectal mucus by faecal extracts

Experiments were carried out to assess the susceptibility of normal and inflammatory bowel disease rectal mucus to desulphation and desialation by faecal extracts and by bacterial sialidase. The effects were assessed histochemically using a combined high iron diamine (HID) and alcian blue (AB) stain for sulphomucins and sialomucins. Rectal mucus in biopsies from controls (irritable bowel syndrome) and patients with ulcerative colitis or Crohn's disease was resistant to desialation by Clostridium perfringens sialidase, but susceptible to desialation and desulphation by bacteria-free extracts of normal faeces. Periodic acid-Schiff (PAS) staining of adjacent sections similarly treated showed retention of neutral mucus. One faecal extract selectively desulphated all 42 biopsies, causing the goblet cells to change from HID positive to AB positive, suggesting that most, or all HID positive cells also contain sialomucins. This alters the interpretation of previous histochemical studies. Faecal extracts from patients with active ulcerative colitis (n = 6) had desialating and desulphating effects similar to faecal extracts from normal subjects (n = 6). Ulcerative colitis (n = 21), Crohn's disease (n = 18), and control (irritable bowel syndrome) (n = 17) rectal biopsies all showed similar susceptibility to desulphation by a pooled normal faecal extract, but rectal biopsies from patients with Crohn's disease proved more resistant to desialation than control or ulcerative colitis biopsies (p less than 0.02). These studies imply that colonic mucus undergoes continual desulphation and desialation in vivo as a result of faecal enzyme activity that is probably mainly of bacterial origin. Altered susceptibility of colonic mucus to this may be important in the pathogenesis of colonic disease.

Mucosubstance histochemistry of the normal mucosa and carcinoma of the large intestine. Galactose oxidase-Schiff reaction and lectin stainings

Thirty-four cases of carcinoma of the human large intestine were studied employing a battery of histochemical techniques to identify and characterize mucosubstances, including galactose oxidase-Schiff (GOS) reaction and stainings with horseradish peroxidase-labeled lectins. The results disclosed that the goblet cell-type mucin (GCM) of the left colon differed from that of the right colon in containing 8-O-acetylated N-acetylneuraminic acid (NANA) more abundantly and 8-O-acetylated NANA-(alpha Fuc)-beta Gal type terminal structures. The right colonic GCM, on the other hand, was shown to contain alpha Fuc-beta Gal type predominantly. Surface coat-type mucin (SCM) showed consistent histochemical reactivities regardless of the sites in the large intestine. The transitional mucosa surrounding carcinoma tissues characteristically revealed decreased sulfation and neuraminidase-induced GOS reactivity, suggesting the presence of NANA-beta Gal type terminals. The carcinoma tissues resembled the transitional mucosa in showing neuraminidase-induced GOS reactivity, but differed from the latter in possessing intense UEA-I reactivity. The present study indicated that the refined histochemical techniques recently developed were quite useful for understanding the histochemical reactivities correlating with sugar structures.

Morphology and histochemistry of the mucosa surrounding small oligotubular adenomas of the large bowel

The transitional mucosa surrounding adenomas and carcinomas of the large bowel is characterized by a reversion of mucus secretion from sulphomucin to sialomucin and a hyperplasia of crypts and epithelial cells. The specificity of this phenomenon is still a controversial issue. Therefore we studied 72 oligotubular adenomas of the large bowel and the adjacent mucosa by means of histochemistry and morphometry. The peak of sialomucin production is found within the crypts immediately adjacent to the adenoma, whereas the more distant crypts secrete less. The cellular diameter and the depth of the crypts behave in a similar manner, they decrease with increasing distance from the adenoma, still being much higher than in the normal mucosa. The crypt depth correlates well to sialomucin production. The existence of the transitional mucosa around small oligotubular adenomas may indicate, that this mucosal change is not merely secondary to the presence of carcinoma but may be of importance as a precursor lesion of neoplastic changes of the colon and rectum.

Mucosal abnormalities at the anastomosis site in patients who have had intestinal resection for colonic cancer

Twenty eight patients with colonic cancer, who were asymptomatic after intestinal resection and anastomosis, underwent colonoscopy as part of their routine follow up, and biopsies were obtained from the anastomosis and several other sites. Sections were stained by haematoxylin and eosin, several methods for mucin, and by the peroxidase-antiperoxidase method for carcinoembryonic antigen. Non-specific inflammatory changes were seen at the anastomosis in 11 of the 28 cases, apparent in several two years after operation; focal surface ulceration was seen in over half these samples. Neither dysplastic nor adenomatous change was detected, but at seven anastomoses the so called transitional change, which has been regarded as a preneoplastic change, was apparent. There was no consistent alteration in carcinoembryonic antigen reactivity. It is concluded that there is morphological evidence of a continued stimulus to regenerative activity at some anastomoses and that this may represent a promoting factor enhancing further carcinogenesis.

Mucosubstance histochemistry of the normal mucosa and epithelial neoplasms of the large intestine

Histochemical properties of mucosubstances in normal mucosa and neoplasms of 100 operated cases with colonic carcinoma were investigated by using several new methods, such as paradoxical concanavalin A (con A) staining and modified PAS reactions for sialic acids. Acidity of goblet cell-type mucin (GCM) of the normal mucosa varied with the depth of the crypt, as well as with different segments of the large intestine, whereas surface coat-type mucin (SCM) mainly consisted of sulfomucin throughout the large intestine. In addition, the PAS reactivity revealing the presence of O-acetylated sialic acid and the labile class III con A reactivity were demonstrated as hallmarks characterizing the colonic GCM. In carcinoma tissues, sialomucin was more abundant than in the normal mucosa. Goblet-type tumor cells were found in 59 cases. Moreover, O-acetylated sialic acid and the labile class III con A reactivity persisted in GCM of the goblet-type tumor cells. GCM of the adjacent mucosa of the neoplasms showed a decrease in sulfomucin in 95 cases and a marked increase in the labile class III con A reactivity in 97 cases, while the histochemical properties of SCM in this region remained unchanged.

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. III. Changes in the histochemical and chemical properties of the epithelial glycoproteins in the mucosa close to colonic tumours

Histochemical, chemical and histological studies were performed on 26 specimens of human colonic tumours and 62 specimens of mucosa taken at distances of 0.5-5.0 cm from the tumour. The tumour glycoproteins were divided almost equally between three anionic types, sulphomucin, sialomucin and mixed sialomucin and sulphomucin. All showed a reduction in staining for side chain O-acylated sialic acid. In 56% of the tumours, this was accompanied by loss of glycoprotein while, in 44%, abundant mucin was still present. Histochemical examination of the mucosal specimens indicated that in 24.2% the side chain O-acylated sialic acids did not differ from normal. In 41.9% there was a focal change and in 33.9% there was a generalized field reduction in the proportion of side chain O-acyl sialic acids. The latter were subdivided into moderate and severe. Chemical analyses correlated well with the histochemical classification of the mucosal specimens and showed that, on average, the classifications focal and severe field change were not due to sampling error. Forty-five per cent of the cases showed only focal change and 40% only field change. Mucosal specimens associated with 60% of the moderately differentiated tumours showed only focal change while those associated with 75% of well-differentiated tumours showed only field change. Abnormal patterns of staining for side chain O-acylated sialic acids (a) were largely independent of the distance from the tumour, (b) occurred in the presence of a normal pattern of staining for sialomucins and sulphomucins and (c) were associated with 61.4% of the specimens that showed no discernible evidence of histological abnormality. In contrast, only one specimen showed evidence of histological change without a corresponding change in O-acylated sialic acids. The data suggest that abnormal patterns of staining for O-acylated sialic acids may represent premalignant change but their precise significance and specificity requires further studies of non-neoplastic diseases of the colon.

Early colonic dysplasia: comparison of differential mucin staining and tritiated thymidine labeling

Controversy has arisen regarding the interpretation and significance of histochemical changes in the mucin produced by the globlet cells in colonic mucosa. The shift from sulfomucin to sialomucin, which is readily identified utilizing high iron diamine-alcian blue staining techniques, has been alternately interpreted as a specific, early dysplastic and premalignant change or a nonspecific generalized response to trauma and inflammation, among others. An attempt to clarify this issue was made by comparing mucin changes identified by high iron diamine-alcian blue staining techniques with increases in DNA synthetic activity identified utilizing autoradiographic analysis of tritiated thymidine uptake. Male Holtzman rats were treated with 15 weekly subcutaneous injections of dimethylhydrazine (30 mg/kg per week) (10 rats) or placebo (10 rats). The colons were prepared and fixed, sequential sections were stained with hematoxylin-eosin or high iron diamine-alcian blue, autoradiography was performed. Analyses of labeling index showed no difference in normal background crypts between the control and treatment groups nor in crypts adjacent to those displaying abnormal mucin staining. Crypts with abnormal mucin production (sialomucin dominant) had significantly higher labeling indexes when compared with those of control animals (p less than 0.005). These findings indicate that the shifts in mucin production identified with high iron diamine-alcian blue staining represent crypts with increased and abnormally distributed mitotic activity that is an early dysplastic response to the carcinogenic stimulus.

Histochemical identification of side chain substituted O-acylated sialic acids: the PAT-KOH-Bh-PAS and the PAPT-KOH-Bh-PAS procedures

Two new methods, based on the original periodic acid-Thionin Schiff-saponification-periodic acid-Basic Fuchsin Schiff (PAT-KOH-PAS) technique of Culling et al. (1976), have been devised for the histochemical identification of side-chain O-acylated sialic acids. In the first of these, the periodic acid-Thionin Schiff-saponification-borohydride reduction-periodic acid-Basic Fuchsin Schiff (PAT-KOH-Bh-PAS) procedure, the specificity of the original PAT-KOH-PAS technique was improved by: (a) extending, when necessary, the initial period of periodate oxidation, (b) increasing the period of exposure to Thionin Schiff reagent from 30 min to 4 h, (c) using a Thionin Schiff reagent prepared by a different method, (d) interposing a borohydride reduction step between the saponification and PAS steps and, (e) extending the period of oxidation in the final PAS step from 10 to 30 min. In the second procedure, the periodic acid-phenylhydrazine-Thionin Schiff-borohydride reduction-periodic acid-Basic Fuchsin Schiff (PAPT-KOH-Bh-PAS), based on the periodic acid-phenylhydrazine-Schiff (PAPS) technique of Spicer (1961), blue Thionin Schiff staining was confined to sialic acid residues with oxidizable side chain vicinal diols by interposing a treatment with 0.5% (w/v) aqueous phenylhydrazine hydrochloride for 2 h at room temperature between the initial periodic acid oxidation and the Thionin Schiff steps of the PAT-KOH-Bh-PAS procedure. These procedures are discussed within the general framework of the methods available for the histochemical identification of side-chain O-acylated sialic acids.

Differential mucin staining in colorectal neoplasms. Potential clinical application

Screening techniques that can identify histochemically different mucin production by colonic mucosa have been claimed to be able to identify early dysplastic changes in the colon and rectum. Controversy has arisen regarding interpretation of these changes, and this study has attempted to address this issue. Utilizing a high iron diamine-alcian blue staining technique, several benign and malignant pathologic conditions of the colon were evaluated. Significantly abnormal staining patterns were identified at the resection margins of all patients in whom either anastomotic recurrence or metachronous carcinomas developed compared with patients who were without recurrence for more than 5 years. It is postulated that this technique may be useful in prospectively identifying this group of patients at high risk for the development of recurrence.

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. I. A comparison between histologically normal colon, colonic tumours, ulcerative colitis and diverticular disease of the colon

Chemical and histochemical methods were used to compare the epithelial glycoproteins from formalin-fixed surgical specimens of normal human large intestine, colonic tumours, ulcerative colitis and diverticular disease. All the epithelial glycoproteins contained fucose, galactose, glucosamine, galactosamine and, in addition, sialic acids both with and without O-acyl substituents in the side chain and/or at position C4. The glycoproteins of the normal ascending and descending colons differed significantly with respect to the percentage of the sialic acids released following digestion of the de-O-acylated glycoprotein with Vibrio cholera neuraminidase and to the molar fucose-sialic acid ratio. Statistical analysis of the chemical data showed that (a) compared to normal, the sialic acids of the tumour and ulcerative colitis glycoproteins from the descending colon were significantly less substituted in the side chain and at position C4; (b) the O-acetyl substitution pattern of the sialic acids of the ulcerative colitis glycoproteins from the ascending colon and the quantitative composition of the carbohydrate prosthetic groups of the ulcerative colitis glycoproteins from both ascending and descending colons differed from normal; (c) it was not always possible to distinguish between the ulcerative colitis and tumour glycoproteins on the basis of the O-acetyl substitution pattern of their sialic acids; and (d), there were minor differences between normal glycoproteins and those from cases of diverticular disease.

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. II. A comparison between histologically normal small intestine and Crohn's disease of the small intestine

Comparative chemical and histochemical studies were performed on formalin-fixed, surgical specimens of human small intestine from cases of Crohn's disease and normal controls. The sialic acids of the crude glycoproteins isolated from normal ileum were significantly less neuraminidase-susceptible and more C4 substituted (P less than 0.01) than those of the glycoproteins isolated either from normal upper small intestine (duodenum and jejunum) or from cases of Crohn's disease of the ileum. Fractionation yielded two major sialic acid-containing fractions, eluting from DEAE-cellulose with 0.2 M or 0.3 M sodium chloride. Both fractions contained fucose, galactose, glucosamine and galactosamine in addition to sialic acids both with and without O-acyl substituents at position C4 and/or in the side-chain (side-chain O-acylated sialic acids were also detected by histochemical procedures). The fractions differed significantly from one another with respect to the neuraminidase susceptibility of their sialic acids (P less than 0.01), the percentage of C4 (P less than 0.01) and side-chain substituted sialic acids (P less than 0.05), and the molar fucose-sialic acid ratio (P less than 0.05). The O-acyl substitution patterns of the sialic acids of both the 0.2 M and 0.3 M fractions of the upper small intestine glycoproteins differed significantly from those of the corresponding fractions from normal ileum, while the sialic acids of the 0.2 M fractions from Crohn's disease of the ileum differed significantly from normal with respect to neuraminidase susceptibility (P less than 0.01) and percentage C4 substitution (P less than 0.01); the 0.3 M fractions differed only in the percentage of sialic acids substituted at C4. The differences between the sialic acids from the normal and Crohn's disease specimens were shown to be independent of either the anatomical origin of the specimen or the histopathological sub-group of the Crohn's disease specimens; no significant differences were noted between the sub-groups but all the sub-groups differed from normal.

Sialomucin in Paget cells of extramammary Paget's disease

The cytoplasmic sialomucin in Paget cells of extramammary Paget's disease was examined by means of a battery of histochemical techniques. The staining methods used involved an electrolyte--Alcian Blue (pH 5.8), periodic acid--Schiff and azure A at selected pH levels. Methylation, saponification, borohydride reduction, acid hydrolysis, and digestion with diastase, neuraminidase (Vibrio cholerae) or chondroitinase ABC, were also employed. The cytoplasmic mucin was found to exhibit positive reaction for the above staining which were variously altered by the chemical modification procedures and diminished in intensity or abolished by digestion with neuraminidase. These results suggest that the cytoplasmic mucin is sialomucin without side-chain substituent in extramammary Paget's disease located in axillary or genital area, and with a substituent at C7 in the disease located in perianal area.

Juvenile and inflammatory polyps of the colon--a histological and histochemical study

A light microscopy and histochemical study of 24 juvenile and 27 inflammatory polyps showed that both may derive from inflammatory processes. Granulation tissue, secondary to spontaneous local inflammation or due to surgical procedures may subsequently be covered by regenerating epithelium which lines haemorrhagic cavities and mucus lakes to form irregular, elongated and cystic glands, which are characteristic of juvenile polyps. Both juvenile and inflammatory polyps showed cystic, metaplastic and 'transitional-type' glands. The mucin distribution was identical in both types of polyps. All these findings suggest a common origin of the polyps. The presence of 'transitional-type' glands seems to confirm these as a secondary regenerative phenomenon rather than pre-neoplastic, although dysplastic changes in juvenile polyps have been described. It is suggested that both the juvenile and inflammatory polyps may undergo dysplasia only in genetically predisposed subjects. However, this event seems to be very rare.

Mucin secretion and morphological changes of the mucosa in non-neoplastic diseases of the colon

Changes in mucin secretion and increase in height of the colonic mucosa adjacent to colorectal carcinoma (transitional mucosa) have been considered pre-malignant. In this study similar changes (both morphological and histochemical) have been found in some cases of ulcerative colitis and ischaemic colitis, as well as in juvenile, inflammatory and hyperplastic (metaplastic) polyps. 'Transitional' patterns of mucin secretion also occur in some other cases of ulcerative colitis, colostomies and Crohn's disease of the colon in which the mucosa has a normal height, suggesting the changes in mucin secretion are independent of mucosal morphology. In all these pathological conditions, hyperplastic (metaplastic) mucosa also coexisted. These findings seem to suggest that: (1) 'transitional' changes more likely represent a secondary regenerative phenomenon rather than a premalignant one; (2) the pattern of mucin secretion is not selective enough to serve as a premalignant marker; therefore is not a valid prognostic indicator in colonic biopsies; (3) hyperplastic (metaplastic) changes might derive from 'transitional' mucosa as a result of a more mature phase of this exaggerated regenerative phenomenon. However, in some patients longstanding 'transitional' mucosa may lead to dysplasia under the influence of environmental and genetic factors.

A scanning electron microscopy study of changes in the colonic mucus layer during chemical carcinogenesis

Scanning electron microscopy was used to examine the appearances of the colonic mucus layer of rats during chemical carcinogenesis with dimethylhydrazine. The normal colonic mucus layer had a dense homogeneous appearance and provided a complete cover for the mucosal epithelium. At high magnifications tiny fenestrations could be seen in this mucus layer. During carcinogenesis these fenestrations enlarged, increased in number, and coalesced, causing focal defects in the mucus layer, which eventually broke into strands and clumps of mucus. The findings indicate that the colonic mucus layer develops progressive abnormalities during carcinogenesis which result in breakdown of its integrity and exposure of the mucosal epithelium to colonic contents.

Carbohydrate patterns of endoscopic mucosal biopsies in cancer of the stomach and chronic gastritis

The monosaccharide composition of the soluble glycoproteins of endoscopic gastric biopsies was studied with gas-liquid chromatography in patients with carcinoma of the stomach and in patients with chronic gastritis (controls). The analyses showed (1) that monosaccharide patterns were similar in the antrum and corpus of patients with chronic gastritis, (2) that the mannose content relative to the galactose content was increased in the tumor as compared with the antrum of the same stomach (p less than 0.05) and with the antrum (p less than 0.05) and corpus (p less than 0.02) of the control stomachs, and (3) that the N-acetylgalactosamine and N-acetylglucosamine content tended to be decreased in the tumor area as compared with the antrum and corpus of control stomachs. The changes in the histologically tumor-free part of the corpus of the cancer stomachs tended to be similar in direction to those in the tumor itself.

The 'transitional' mucosa adjacent to large bowel carcinoma--electron microscopic features and myofibroblast reaction

An electron microscopic study of the 'transitional' mucosa adjacent to 10 carcinomas of the colon showed impaired maturation of epithelial cells. The pericryptal fibroblast layer was absent, accounting for an increase in the length and distension of crypts. In the tunica propria a massive accumulation of myofibroblasts was noted and was indicative of an intensive fibre-producing activity. Review of the literature identifies various theories concerning the functions of myofibroblasts in respect of contraction, embryonal collagen-fibre formation and non-specific stromal reaction. Of these, the latter two are considered likely in relationship to transitional colonic mucosa.

Mucin histochemistry of the anal canal epithelium. Studies of normal anal mucosa and mucosa adjacent to carcinoma

The epithelial lining of the anal canal is of colo-rectal type in the upper part and squamous in the lower part, while the middle zone is called the anal transitional zone (ATZ). This zone is characterized by an epithelium which bears a resemblance to that of the anal glands and shows little mucus secretion. The histochemical properties of the mucins in the epithelium of 39 anal canals, resected for ano-rectal adenocarcinoma, basaloid carcinoma, squamous carcinoma and malignant melanoma were investigated. The study reveals that (1) the mucin composition of the ATZ epithelium corresponds to that of the anal glands, being characterized by a mixture of sulpho- and sialomucins with scarcity or absence of O-acylated sialic acids; and (2) cases with carcinomas located near the dentate line show changes in the mucin composition of the adjoining anal canal epithelium, regardless of tumour type. In colo-rectal type mucosa, these mucins consist of increasing amounts of sialomucins with a predominance of N-acyl derivatives, and in the anal glands of increasing amounts of sulphomucins and O-acyl derivatives of sialomucins. No changes could be detected in the ATZ epithelium. It is concluded that rectal and anal glands in the anal canal are exposed to stimuli which alter the normal process of glycoprotein synthesis and secretion. The changes seem to be secondary to tumour growth and independent of the histological type of tumour.

A scanning electron microscopy study of ultrastructural changes in the colonic mucosa of patients with large bowel tumours

Scanning electron microscopy (SEM) has been used to compare the appearances of the colonic mucosal surface and overlying mucus layer of patients with normal colons, adenomatous polyps and colorectal carcinoma. The normal colonic mucosa had a characteristic orderly arrangement of crypts and was completely covered by an intact mucus layer. Epithelial and cryptal irregularities were seen on the surface of both polyps and carcinomas, and, in addition, the mucus layer was fragmented, leaving areas of the underlying epithelium exposed. These changes were more marked in colorectal cancers than in polyps and were present to a lesser degree in the apparently normal mucosa adjacent to tumours. The findings indicate that SEM can detect minor subtle irregularities on the surface of the colon and so may be useful in detecting pre-neoplastic and early neoplastic changes.

Patterns of mucin secretion in neoplastic and non-neoplastic diseases of the colon

Changes in the pattern of sulfomucin and sialomucin secretion and height of large bowel mucosa have been described adjacent to primary colonic adenocarcinomas and adenomas, and called "transitional" mucosa. These changes were initially thought to be specific preneoplastic changes. In this study "transitional" changes in colonic and rectal mucosa were found in some cases overlying benign mesenchymal tumors, metastatic tumors from noncolonic sites, and sites of endometriosis, as well as adjacent to primary colonic and rectal neoplasms. These findings suggest that although these changes may be found adjacent to primary large bowel neoplasms, they are frequently secondary reactive rather than primary preneoplastic phenomena. In addition, the thickness of the mucosa and the accompanying pattern of mucin secretion usually seen in transitional mucosa may be dissociated.

"Transitional" and hyperplastic-metaplastic mucosa occurring in solitary ulcer of the rectum

Non-polypoid hyperplastic mucosa similar to that adjacent to colorectal carcinomas and adenomas, the so-called "transitional mucosa" (TM), was found in 16 out of 27 cases of solitary ulcer syndrome of the rectum. In 18 cases fully developed hyperplastic (metaplastic) mucosa was also found. It is suggested that chronic ischaemia which takes place in the solitary ulcer syndrome leads to TM as an exaggerated regenerative phenomenon. Later maturation of TM could lead to hyperplastic (metaplastic) changes.

Tissue culture of human epithelial cells from benign colonic tumors

Human colonic epithelial cells from three classes of benign tumors have been reproducibly cultured free of fibroblasts for 8 wk using a supplemented Medium 199 (M 199S). The cultured colonic cells were identified as epithelial by the presence of junctional complexes (tight junctions, gap junctions, and desmosomes), a brush border on the apical surface, keratin fibrils, and by both a close-packed columnar or cuboidal morphology and the capability to transport water and ions to form hemicysts. Colony formation was initiated by groups of epithelial cells, not by single cells, and was inhibited by cocultivation with either lethally irradiated 3T3 cells or human diploid fibroblasts. Enhancement of epithelial colony formation was observed following culture on nonadherent, "floating" substrates compared with substrates attached directly to the bottom of the culture dish. Replication of epithelial cells in M 199S from the class of benign colonic tumors least prone to malignancy, the tubular, was significantly enhanced by epidermal growth factor (EGF). In contrast, EGF did not stimulate the growth of cells in M 199S from the other classes of benign tumors, the villotubular and the villous, which exhibit more malignant potential. These data imply that premalignant colonic epithelial cells lose responsiveness to growth modulation by EGF as they progress toward frank carcinoma.

The cytoplasmic mucin in Paget cells of extramammary Paget's disease

The cytoplasmic mucin in the Paget cells of extramammary Paget's disease was examined with a battery of histochemical techniques. The staining methods used were alcian blue, azure A and periodic acid-Schiff. In a further attempt to identify various polyanions, staining was carried out with alcian blue containing various concentrations of electrolyte. Methylation, saponification, borohydride reduction, acid hydrolysis, and digestion with diastase, sialidase, chondroitinase ABC, or nucleases were also employed. The results obtained suggest that the cytoplasmic mucin in the Paget cells is sialomucin without side-chain substituent.

Purification and composition of colonic epithelial mucin

Colonic mucin was purified from homogenized scrapings of rat colonic epithelial cells using gel filtration and ion-exchange chromatography. High molecular weight water-soluble mucin was separated from low molecular weight proteins by gel exclusion chromatography on Sepharose 4B, and was further separated into two major mucin fractions and several non-mucin fractions on DEAE-cellulose. Fraction IV, the major mucin, was a sulphated glycoprotein with 62% carbohydrate by weight, and high concentrations of serine and threonine. A more acidic mucin, fraction V, had similar composition. Approx. 85% of the sialic acid of fractions IV and V were removed after incubation with Clostridium perfringens neuraminidase. Blood group A but not group H activity was present in fractions III, IV, and V. Ultracentrifugation experiments showed that fraction IV migrated as a single peak, whereas fraction V contained two components. Our study indicates that colonic mucin consists of at least two closely related acidic high molecular weight glycoproteins which can be separated from non-mucin contaminants by ion-exchange chromatography.

Transitional mucosa and survival in human colorectal cancer

The mucosa in 100 segments of colon and rectum resected for cancer were examined using light microscopy and histochemical techniques. The extent of abnormal or transitional mucosa was defined for each case. Transitional mucosa was present in 93 of 95 adenocarcinomas and one malignant melanoma. The average total length of transitional change was 3.4 cm the maximum length was 19.5 cm. An inverse correlation was observed between the survival and the length of transitional mucosa around locally invasive (Dukes' B) carcinomas (P = 0.005). This may be related to increased amounts of sialic acid in transitional mucosa and the ability of sialic acid to depress tumor immunogenicity. The raised levels of sialic acids in transitional mucosa may have practical value in assessment of prognosis in colorectal cancer.

Specific techniques for the identification of O-acylated sialic acids in colonic mucins

The development of methodology for the histochemistry of mucins based upon their PAS reactivity is discussed in terms of mechanism, specificity and application. Two new histochemical methods (PB/KOH/PAS and PAT/KOH/PAS), supplemented by a variety of new and standard histochemical techniques, and correlated by parallel chemical studies, were used to demonstrate and identify C4 and side chain O-acylated sialic acids in colonic epithelial mucins. The application of these methods in the field of histopathology is discussed.

Morphology and histochemistry of large intestinal polyps

In order to assess the progress of the growth of large intestinal polyps into cancer, the epithelial height and the size of the epithelial nuclei were measured. Mucin histochemistry was also carried out. The increase of the histologic grade was based on the extent of epithelial pseudostratification; epithelial height became greater and epithelial nuclei increased in size. The histochemical mucin values were as follows: the total amount of murin in a given area increased in grade I epithelia in comparison with its behaviour in normal ones, and then decreased gradually with the increase in histologic grade. Neutral mucin became more conspicuous with the increase of epithelial pseudostratification. The amount of sulphated mucin decreased with the increase in histologic grade. In normal epithelia, sialomucin was rarely seen, but in grade I and II epithelia which did not show nuclear stratification the amount of sialomucin increased strikingly. It then decreased in amount with the increase in histologic grade. The noticeable increase of the amount of sialomucin in grade I and II epithelia can be thought of as a temporary pheomenon which appears in an early stage of carcinogenic process. The large intestinal polyps go through several stages before turning into cancer.