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11 beta-hydroxysteroid dehydrogenase type II in human colon: a new marker of fetal development and differentiation in neoplasms.

The colon plays an important role in water and electrolyte homeostasis and is a major target tissue for aldosterone. 11 beta-Hydroxysteroid dehydrogenase type II enzyme (11 beta HSD2) confers specificity to the non-selective mineralocorticoid receptor by inactivating glucocorticoids, thus allowing binding by mineralocorticoids. Using immunohisto/cytochemistry and Northern blot analysis, we examined 11 beta-HSD2 expression in human fetal colon (23 cases ranging in age from 15 to 40 weeks gestation), neonatal colon (2 cases, 6 and 12 months old), normal adult colon (15), adenoma (35), adenocarcinoma (34) and the human colonic epithelial cell line T84, in the presence or absence of sodium butyrate, to study the correlation between enzyme expression and cellular or neoplastic differentiation. In fetal colon, weak 11 beta-HSD2 immunoreactivity was detectable in superficial epithelium from 25 weeks gestation, but normal adult levels were apparent only after 40 weeks gestation, suggesting that fully developed aldosterone induced electrolyte transport can occur only at late gestational stages. In adult normal colon, superficial absorptive cells at the top of crypts were strongly positive for 11 beta-HSD2, whereas immunoreactivity was weak in adenomas and carcinomas, and the pattern of localization varied among patients. Northern blot analysis performed on 4 cases of adenocarcinoma also demonstrated lower levels of mRNA than autologous non-neoplastic colonic mucosa. In carcinomas, 11 beta-HSD2 immunoreactivity was more frequently detected in differentiated structures, such as those forming glandular or tubular structures. Studies with T84 cells showed that expression of 11 beta-HSD2 was markedly enhanced with the addition of sodium butyrate, a well known inducer of cell differentiation in colonic epithelia. These results suggest that the expression of 11 beta-HSD2 is associated with differentiation or maturation in human colonic epithelia and that the enzyme may serve as a useful marker in development and disease.

11-beta-Hydroxysteroid Dehydrogenases↗

Virtual colonoscopy in the detection of colonic polyps and neoplasms.

First introduced in 1994, CT colonography (Virtual colonoscopy) has emerged as an accurate, non-invasive test that will likely play a future role in colorectal cancer screening. Over the past 3 years, there have been dramatic improvements in both hardware and software technology relating to CT colonography resulting in shorter scan times, enhanced user-friendliness and improved performance statistics. Published results show the accuracy of CT colonography to be comparable to conventional colonoscopy for detection of polyps >6mm in size with few false-positives. While many of the technical aspects of CT colonography have now been standardised current interest focuses on the development of faecal tagging agents to avoid full bowel catharsis and the use of low dose multislice CT acquisition to reduce patient radiation exposure. This chapter will summarise the development of CT colonography to date, document its published performance in detection of colorectal polyps and cancers, and review its current and potential future uses.

Colonic Neoplasms↗

Expression of epidermal growth factor receptor in normal colorectal mucosa, adenoma, and carcinoma.

Using the monoclonal antibody EGF-R1, the expression of epidermal growth factor receptor (EGFR) was investigated immunohistochemically in normal colonic mucosa distant from and adjacent to colonic neoplasms, in 25 adenomas and in 144 unselected colorectal carcinomas. EGFR expression was an inconsistent phenomenon in each of these conditions. It was not expressed in 23/44 non-neoplastic mucosa specimens distant from and in 26/44 mucosae adjacent to colon tumours; 15/25 adenomas and 71 (49.3%) of the carcinomas failed to contain detectable amounts of EGFR. In contrast, large amounts of EGFR were found in 4 non-neoplastic mucosae at both locations, in 3 adenomas and in 11 (7.6%) carcinomas. The remaining cases showed complex patterns of EGFR-expression. In comparing mucosae close to and distant from a colonic tumour, only minor differences in EGFR content were observed. The intra-individual comparison of the mode of EGFR expression in non-neoplastic and neoplastic epithelium revealed an overexpression of EGFR in carcinomas in about one third of the 44 cases examined. One third showed no obvious differences, and one third showed lower levels of EGFR expression within the tumour. We conclude that the mode of EGFR expression in normal and neoplastic colon epithelium is variable and reflective of inter-individual constitutive differences rather than of abnormalities in gene regulation. Statistical analysis failed to reveal correlations between the mode of EGFR expression and tumour grade, type or Dukes stage.

Adenoma↗

A multicenter, multiyear, case-controlled study of the risk of colonic polyps in patients with gastric polyps. Are gastric adenomas a new indication for surveillance colonoscopy?

A multicenter, multiyear, case-controlled colonoscopic study of 41 patients with gastric polyps undergoing colonoscopy analyzed whether patients with gastric polyps, particularly adenomas, run an increased risk of having colonic polyps. The primary controls were 109 patients undergoing colonoscopy matched for age and colonoscopy indications. A secondary control group was 69 of these 109 patients who, in addition to matching for age and colonoscopy indications with study patients, had no gastric polyps demonstrated by upper gastrointestinal examination. Patients with nonmalignant mucosal gastric polyps had a significantly greater incidence than primary controls of colonic polyps [odds ratio (OR) = 3.19, OR confidence interval = 1.46 - 6.99, p < 0.004, chi(2)], colonic neoplasms (OR = 3.58, OR confidence interval = 1.56 - 8.23, p < 0.006, chi(2)), and colonic cancer (OR = 4.5, OR confidence interval = 1.05 - 19.4, p < 0.04, Fisher's exact test). Moreover, patients with gastric adenomas had a significantly greater incidence than did primary controls of colonic polyps (OR = 7.6, OR confidence interval = 1.29 - 44.7, p < 0.02, Fisher's exact test). The association between gastric and colonic polyps did not arise as an artifact of the significantly higher frequency of females in the study group because this association remained after patient stratification by sex. The higher risk of colonic polyps in study patients did not arise as an artifact of unappreciated gastric polyps in the primary controls because study patients also had a significantly higher risk of colonic polyps than the secondary controls (OR = 3.21, OR confidence interval = 1.35 - 7.63, p , 0.01, chi(2). Our retrospective case-controlled study suggests that gastric adenomas may be a new, significant risk factor for colonic polyps. A strong association would require that patients with gastric adenomas undergo surveillance colonoscopy to diagnose and remove colonic polyps. However, before we apply this finding to clinical practice, the apparent association should be confirmed by another, preferably prospective study.

Aged↗

[Bone metastases of colonic and rectal neoplasms. Apropos of 11 cases].

The authors report 11 personal cases and discuss the characteristics of bony metastases in carcinoma of the colon and rectum. The frequency of these metastases is fairly low (1.3% of all cases of bony metastases) as tumours of the large intestine do not tend to migrate to the bones. Sometimes bony metastases are the presenting symptom but, usually the metastases occur within 5 years of the diagnosis of the primary tumour. The clinical picture shows no special characteristics. Radiologically, these bony metastases may be either single or multiple. Their distribution recalls that of other metastases in the bones with a few differences, however. The special frequence of pelvic involvement, distal localisations (hands or feet) are not exceptional. Metastases usually give rise to osteolysis. The mixed appearances are, however, not rare, and usually give a pseudo-sarcomatous appearance, with invasion of the soft parts and very marked periosteal reaction. Sometimes, bony condensation may be noted. The treatment of rectal and colonic cancer with bony metastases, is disappointing as the disease is always fatal within a relatively short period, usually less than one year after the diagnosis of the bone involvement. The histological appearances of the bony lesions depend on differenciation of the tumour and the characteristics of the neighbouring bony abnormalities which, in our experience, usually include both osteolysis and osteogenesis.

Age Factors↗

[Familial colon cancer].

5 families with autosomal dominant inherited colonic cancer were analyzed with reference to the characteristics of familial colonic cancer: 45% out of 54 family members had colorectal carcinomas, with a mean of 4.5 affected members per family. The mean age on diagnosis of colonic cancer was 43.9 years. 50% of the colorectal carcinomas were located in the right colon; 11 out of 14 carcinomas were Dukes C, with a predominance of poorly differentiated adenocarcinomas and mucin-producing cancers. 22% had synchronous cancers and 13% developed metachronous cancers. Cancer at another location was found in 8.7% of cases. Prospective screening of relatives (siblings, children) revealed a colonic neoplasm in 3 out of 6 asymptomatic subjects. The typical characteristics of familial colonic cancers were demonstrable in our patients. The elucidation of an exact family history in all patients with colorectal carcinoma and a strategy of meticulous surveillance are absolutely necessary for the diagnosis and management of this inherited trait.

Adenocarcinoma↗

Pit pattern and three-dimensional configuration of isolated crypts from the patients with colorectal neoplasm.

BACKGROUND: This study examined the usefulness of magnifying videoscopic pit-pattern diagnosis in the differential diagnosis of colonic neoplasms. The relationship between pit patterns and the three-dimensional configuration of the neoplastic gland was evaluated for its contribution toward an understanding of pit patterns. METHODS: A total of 3005 colorectal lesions were examined endoscopically and histopathologically. Pit patterns were classified into six types. All materials used for crypt isolation were derived from segments of 21 colorectal lesions and one normal colonic mucosa. For the crypt isolation, the HCl-digestion method was used. RESULTS: The magnifying videoscopic diagnosis was comparable with the histological diagnosis in the 3005 colorectal lesions. Isolated crypts with the type-I pit pattern resembled a test-tube; the type-II pit pattern was also tubular, but had observed fissures at the bottom; the type-III l pit pattern was a reversed triangle or tongue-like in shape; and the type-III s pit pattern was columnar and either tapered off or meandered. Isolated crypts with the type-IV b pit pattern appeared as long reversed triangles with protuberances, and the type-IV v pit pattern was flat with slender tubules or finger-like processes. The isolated crypts with the type-V pit pattern were complicated and indistinct in shape. CONCLUSIONS: Evaluation of the three-dimensional configuration revealed that when the pit patterns, of each isolated crypt differed, their three-dimensional configurations also differed. Recognition of the differences in the three-dimensional configuration should contribute toward both an understanding of pit-pattern diagnosis and the further development of the endoscopic diagnosis of various colorectal lesions.

Adenoma↗

Reduced p16 expression correlates with lymphatic invasion in colorectal cancers.

BACKGROUND/AIMS: P16, the tumor suppressor gene, plays a crucial role in the most important regulatory pathway involved in the G1/S transition, but its role in gastrointestinal neoplasia remains unclear. METHODOLOGY: To evaluate the possible p16 role in the development of colonic neoplasms, the authors studied p16 immunohistochemical expression of 84 lesions of colorectal cancers, 6 lesions of hyperplastic polyps, 59 lesions of adenomas and 8 lesions of carcinoma in adenoma. Immunohistochemical staining was processed by streptavidin biotin technique. The degree of expression pattern was classified into four types: absent, scattered, or nested, diffuse. Also, the correlation between immunohistochemical expression pattern and clinicopathological features was evaluated. RESULTS: Compared with normal colonic mucosa, in which virtually no p16 expression was observed, p16 was overexpressed in hyperplastic polyps (33%:2/6) adenomas (46%:27/59), carcinoma in adenoma (88%:7/8) and in adenocarcinomas (98%:82/84). In colorectal cancers, when divided into positive (diffuse or nested) and negative (absent or scattered) subgroups, the negative group showed a higher ratio of lymphatic infiltration (p = 0.04), a higher ratio of deeper invasion (p < 0.01) and a higher ratio showing histology of mucinous carcinoma or poorly differentiated adenocarcinoma (p < 0.01). CONCLUSIONS: In colorectal cancers, a significant correlation of reduced p16 expression and lymphatic invasion was observed, which suggested and colorectal cancers with reduced p16 expression have more aggressive potential of lymphatic infiltration. Also a significant correlation between the overexpression of p16 and tumor progression was demonstrated.

Adenocarcinoma↗

Cell lineage markers in premalignant and malignant colonic mucosa.

Normal colonic epithelial cells consist of several cell types or lineages that are thought to arise from a common stem cell precursor. Neoplastic transformation may occur at different stages in the differentiation of a colonic stem cell to produce tumors that may retain characteristic cell lineage phenotypes. In this study, immunohistochemical techniques were used to identify cell lineage-related markers in fetal, normal, hyperplastic, adenomatous, and cancerous colonic tissue. These markers consisted of secretory component (columnar cells), a purified mucin antigen (mucous or goblet cells), chromogranin A (enteroendocrine cells), lysozyme (Paneth cells), and carcinoembryonic antigen (panepithelial cell marker). Colonic neoplasms, like normal mucosa, predominantly expressed the markers of columnar and goblet cell lineages. Chromogranin A was expressed in a small population of cells in most normal and fetal colonic crypts. Chromogranin A reactive cells were found in 55% of hyperplastic polyps, 31% of adenomatous polyps, and 33% of carcinomas. Lysozyme reactivity was rare in fetal, normal, and hyperplastic specimens, but was present in 86% of adenomas and 40% of carcinomas. Of 42 primary carcinomas, 9% were "pluripotent" and expressed markers of all four cell lineages. In addition to columnar and goblet cell markers, 7% expressed both enteroendocrine and Paneth cell markers, 17% expressed enteroendocrine cell markers, and 24% expressed Paneth cell markers. Two cases (5%) lacked expression of any of the cell lineage markers. The remainder expressed only columnar and goblet cell markers. The markers used in this study appear to identify the major cell lineages of fetal and normal colonic epithelium and can be used to delineate the altered cell lineage phenotypes in premalignant and malignant colonic mucosa.

Biomarkers, Tumor↗

Screening for colorectal cancer in Chinese: comparison of fecal occult blood test, flexible sigmoidoscopy, and colonoscopy.

BACKGROUND AND AIMS: Fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), and colonoscopy are the most commonly recommended screening tests for colorectal cancer. The aim of this study was to compare the accuracy and safety of these 3 screening procedures in a general population of ethnic Chinese. METHODS: Asymptomatic adults older than 50 years were recruited from the general public through health exhibitions. All enrolled subjects were offered FOBT and full colonoscopy under sedation. Advanced colonic lesions (defined as adenoma > or = 10 mm, villous adenoma, adenoma with moderate or severe dysplasia, or invasive cancer) were recorded. Lesions at the distal 40 cm in the left colon and rectum were taken as findings of FS. RESULTS: A total of 505 subjects (56% women; mean age +/- SD, 56.5 +/- 5.4 years) were enrolled, and 476 (94.3%) had a complete colonoscopy. Advanced colonic neoplasms were documented in 63 subjects (12.5%), of which 45 had lesions in the distal colon and 26 in the proximal colon. Among the 385 subjects with a normal distal colon, 14 (3.6%) had advanced lesions in the proximal colon that would be missed by FS alone. The sensitivity and specificity of FOBT for advanced colonic lesions were 14.3% and 79.2% and the sensitivity and specificity of FS were 77.8% and 83.9%, respectively. Combining FOBT with FS would not significantly improve the results of FS alone. Among these 505 subjects who underwent colonoscopy and 148 who underwent polypectomy, there was no perforation and only one occurrence of postpolypectomy bleeding recorded. CONCLUSIONS: Colonoscopy is a safe and accurate method for the screening of colorectal neoplasms in Chinese subjects.

Aged↗

Evaluation of the occult blood test in screening for colorectal neoplasms. A prospective study using flexible endoscopy.

Survival rates from colorectal cancer will rise only when polyps and cancers are found at an earlier, curable stage. Consequently, the purpose of the present study was to compare the yield of colonic neoplasms from flexible sigmoidoscopy and colonoscopy with that from occult blood testing. Results from 474 flexible sigmoidoscopies and 1,115 colonoscopies were prospectively recorded during a four-year study period. Colorectal polyps were found in 111 (23.4%) patients undergoing flexible sigmoidoscopy and 325 (29.1%) patients undergoing colonoscopy. Among the 436 patients with polyps, the occult blood test was negative in 282 (64.7%). Among the 51 patients with colorectal cancers, the occult blood test was negative in 20 (39.1%). Thus, testing for occult blood missed the majority of polyps and a large percentage of the carcinomas. These data indicate that lower gastrointestinal endoscopy is superior to occult blood testing as a screening test for detecting colorectal polyps or cancers. Furthermore, given the high incidence of neoplasia in this patient population, the authors suggest that colonoscopy become the screening test of choice for colorectal cancer.

Colonic Polyps↗

Virtual colonoscopy: a gastroenterologist's perspective.

Virtual colonoscopy is an exciting new imaging technique with potential to alter current diagnostic approaches to colonic diseases, particularly colonic neoplasms. Although colonoscopy continues to offer the highest sensitivity and specificity for evaluation of the colon, virtual colonoscopy may offer greater safety, less discomfort, and consequently greater patient acceptance. In addition, virtual colonoscopy offers shorter procedure time, more accurate lesion location, and potentially lower cost as a screening test. Limited data are currently available to define virtual colonoscopy's full clinical role. This article describes the technical considerations, current clinical status, limitations, and potential indications of this new and exciting technology which gastroenterologists should not fear but embrace.

Colonoscopy↗

Sonography as an aid to diagnosis of caecal carcinoma in the elderly.

Many elderly patients with suspected colonic neoplasm are referred to radiology departments for barium enema. Despite routine use of laxatives and colonic washouts and employment of antispasmodic drugs, problems occur with faecal residue and poor retention of barium. This may lead to inadequate demonstration of the caecum. Over a 6-month period sonography following the barium enema allowed a confident diagnosis of a caecal mass lesion to be made in five such patients, whose barium enema had been suspicious but suboptimal. It is suggested that in some patients sonography, where positive, may shorten and facilitate investigation.

Aged↗

Contractile effects and intracellular Ca2+ signalling induced by motilin and erythromycin in the circular smooth muscle of human colon.

Motilin has excitatory effects on the colon of the rabbit and the dog, but little is known of its effect on the human colon. The aim of this study was to investigate the effects induced by motilin and erythromycin A (EMA) on muscle strips and on single cells from primary cultures from human colon. Isotonic contraction was recorded in circular muscle strips from macroscopically normal resection specimens of patients operated on for colonic neoplasm. Agonist-induced intracellular Ca2+ ([Ca2+]i) signalling was studied in primary cultures of colonic smooth-muscle cells using the ratiometric Ca2+ indicator Indo 1, on a laser-scanning confocal epifluorescence microscope. In circular muscle strips, norleucine13-porcine motilin ([Nle13]-pm)and EMA induced tonic contractions with an EC50 of 92 +/- 21 nmol L(-1) and 31 +/- 16 micromol L(-1), respectively. The maximal contraction was 21 +/- 4% (motilin) and 33 +/- 12% (EMA) of the response to 10(-4) mol L(-1) acetylcholine (ACh). The motilin antagonist OHM-11526 (10(-5.5) mol L(-1)) abolished the effects of both [Nle13]-pm and EMA. Neither tetrodotoxin (10(-5.5) mol L(-1)), L-nitro-D-arginine methyl ester (L-NAME) (10(-3.5) mol L(-1)) nor guanethidine (10(-5) mol L(-1)) interfered with the effects of [Nle13]-pm or EMA. [Nle13]-pm (10(-11)-10(-6) mol L(-1)) induced rises of [Ca2+]i in cultured colonic myocytes. At 10(-6) mol L-1, 94% of the cells responded, and half of the cells responded at 1.4 nmol L(-1) [Nle13]-pm. 81% (35/43) and 95% (75/79) responded to EMA (10(-6) mol L(-1)) and acetylcholine (ACh, 10(-4) mol L(-1)), respectively. The motilin antagonist GM-109 inhibited motilin- and EMA-induced [Ca2+]i rises. In the absence of extracellular Ca2+, only 13% (7/52) of the cells responded to [Nle13]-pm (10(-6) mol L(-1)) vs. 90% (47/52) to ACh (10(-4) mol L(-1)). Motilin and EMA have direct excitatory effects on circular smooth muscle from the human colon and these effects are mediated via a smooth-muscle motilin receptor. These findings suggest that motilin may regulate colonic motility and that motilides may have therapeutic potential for the treatment of colonic hypomotility.

Acetylcholine↗

Malignant carcinoid tumor complicating chronic ulcerative colitis.

A case of malignant carcinoid tumor (neuroendocrine carcinoma) of the cecum is described. The neoplasm arose in a patient who had chronic ulcerative colitis for 16 years. There is no previous documentation of this combination, which is surprising, in view of the known association of colonic adenocarcinomas and lymphomas with ulcerative colitis. The reasons for this discrepancy are discussed and it is postulated that ultrastructural examination of poorly differentiated colonic neoplasms may result in a more frequent identification of this association.

Adult↗

Comparison of multidetector computed tomographic colonography and conventional colonoscopy for detection of colorectal polyps and cancer.

BACKGROUND: Computed tomographic colonography (CTC) is a new technique for detecting colonic neoplasms. Data on the utility of this method in the Indian population are limited. METHODS: Forty-two patients with symptoms of colonic disease underwent CTC and conventional colonoscopy (CC) within one week of each other and the findings at these two investigations were compared. RESULTS: The entire colon could be evaluated in 38 patients on CTC and in 23 patients on CC. Of the 19 patients who had incomplete CC, 14 had occlusive colonic lesions. Of the 86 lesions detected on CC, 76 (88.4%) were correctly identified on CTC with regard to location and size. CTC was false negative for 10 lesions and false positive for 5 lesions in 3 patients. The sensitivity and specificity of CTC were 65% and 77%, respectively, for lesions 1-5 mm; 97% and 83% for 6-9 mm-sized lesions; and 100% and 100% for lesions 10 mm or larger. Extracolonic findings were seen in 24 of 42 patients (57%). CONCLUSIONS: CTC is reliable for detecting lesions 6 mm or larger in size. It permits evaluation of the region proximal to an occlusive growth, which is often not possible with CC.

Adolescent↗