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At least 919 records · Page 51Linked to original sources
PubMed1979

Epidemiology of chronic intestinal disease in middle Africa.

Gastrointestinal disease in middle Africa is changing. The traditional patterns were high frequencies of parasitic and infectious diseases and sigmoid volvulus, and low incidences of colonic polyps, carcinoma of the colon, appendicitis, diverticulosis, ulcerative colitis and Crohn's disease. The current disease patterns are compared with those for gastrointestinal disease in developed countries and etiological factors are discussed.

Africa, Central↗
PubMed1979

[Clinical pathology of colonic mucosal polyps].

Of 636 polyps removed during endoscopy between 1973 and 1975 at the University Hospital, Zurich, 36 (5.5%) were of the hyperplastic and 18 (2.8%) of the juvenile type. One polyp was seen in a female patient with Peutz-Jeghers syndrome. The vast majority of the polyps (581, 91.5%) were neoplastic in origin; 70% were tubular adenomas, 16% villous adenomas, and 14% intermediate forms or tubulo-villous adenomas. On the basis of a continuous spectrum in histologic structure and similar cellular dedifferentiation, these three types of adenoma may be viewed as different forms in the development of the same neoplastic process. Hyperplastic and hamartomatous polyps are innocuous, whereas the neoplastic forms may well turn aggressive. Malignant change was observed in 5.1% of our material, particularly in villous adenomas and in polyps exceeding 1 cm in diameter. The presence or absence of invasive growth through the muscularis mucosae is of prime importance for therapy. In accordance with WHO nomenclature, the term carcinoma is used only in the presence of such infiltration. If, in addition, the tumor tissue is not well differentiated, additional segmental resection may be required. The term "focal carcinoma" is no longer in use and has been replaced by "severe focal atypia". In these cases, primary polypectomy for diagnostic purposes is also the optimal therapy, and is as effective here as in cases of benign adenoma.

Adenoma↗
PubMedDate not supplied

[Gastrointestinal polyposis in Bourneville's tuberous sclerosis: an involvement often overlooked].

Ten patients (5 male, 5 female, mean age: 29.4 years) with tuberous sclerosis were investigated for gastrointestinal polyps. Three had adenomatous colonic polyps, one had a single duodenal hamartomatous polyp and the fifth a hyperplastic gastric polyp. This high prevalence (50%) should put the gastro-intestinal investigation as a useful test in the diagnosis of tuberous sclerosis, particularly in the incomplete varieties of disease. Conversely, tuberous sclerosis should be considered in the differential diagnosis of digestive polyposis.

Adolescent↗
PubMed1988

Selenium status and the polyp-cancer sequence: a colonoscopically controlled study.

Diminished blood selenium levels have been associated with increased risk of gastrointestinal cancers in man, while dietary selenium supplementation reduces the incidence of experimental colon cancer in rats. However, no previously published data are available concerning selenium and the evolution of colon cancer from benign neoplastic colonic polyps through localized and metastatic cancer. To assess any influence of selenium on this polyp to cancer sequence, we measured plasma and erythrocyte selenium levels in colonoscopically and histologically evaluated patients with adenomatous polyps (group I), locally resectable colon cancer (group II), metastatic colon cancer (group III), and selected colonoscopy negative controls (group IV). We found no difference in selenium levels between groups IV versus groups I or II. Likewise, within group I, no difference in selenium was present for different polyp histologies or numbers of polyps. However, selenium levels did drop progressively (p = 0.028, ANOVA) from polyp (group I) to local cancer (group II, p = NS vs group I) to metastatic cancer (group III, p less than 0.05 vs group I or group II). Parallel changes were seen in both plasma and erythrocyte levels, suggesting that these selenium abnormalities are of long duration, reflecting tissue stores, and therefore capable of influencing cancer risk. We conclude that selenium stores may not be an important factor in the de novo formation of benign neoplastic colonic polyps. Although these data suggest that selenium does not affect the polyp-cancer sequence, it is possible that a subset of patients with polyps and the lowest selenium levels are at higher risk for malignant transformation. However, these human data do not support a significant role for selenium in colon carcinogenesis.

Aged↗
PubMed1999

Somatic mutations of the first 14 exons of APC in hamartomatous polyps of the colon.

Although hamartomatous or hyperplastic polyps are rarely accompanied by adenomatous or carcinomatous foci, the role of APC (MIM# 175100) mutations in these polyps is not clear. The neoplastic potential of these polyps was assessed with regard to somatic mutation of the first 14 exons of APC. DNA from 14 hamartomatous polyps (12 patients with juvenile polyp, JP; two patients with Peutz-Jeghers syndrome, PJS) and 27 hyperplastic polyps was used. Exons 1-14 of APC were amplified using verified oligonucleotide primers, and PCR-SSCP analysis was performed. Translation-terminating mutation in exon 15 was also screened using the protein truncation test. All mutations found were transitions or transversions with heterozygous alleles of both wild-type and mutant APC in exons 2, 9, 10, and 11. Four hamartomatous polyps (three from JP and one from PJS) showed seven, new mutations and one common APC variant (codon 486), whereas no hyperplastic polyps demonstrated mutation. APC mutation was not correlated with previous history of colorectal carcinoma or number of polyps. Since all mutations were missense or silent mutations occurred in exons not previously known to have functionally relevant area, their phenotypic implication appeared to be limited.

Colonic Polyps↗
PubMed1994

A normal initial colonoscopy after age 50 does not predict a polyp-free status for life.

OBJECTIVES: The prevalence of colon polyps increases with age in the general population. It is unknown whether a lack of adenomatous polyps determined at one time point after the age of 50 is predictive of a subsequent low risk of polyp development. METHODS: Twenty-nine patients between ages 50 and 70 who had no prior history of polyps and had a normal colonoscopy at least 5 yr previously were recruited for follow-up colonoscopy to evaluate the incidence of neoplastic disease in this presumably low-risk group. RESULTS: The incidence of adenomatous polyps after a mean of 5.74 yr was 41.4% (95% confidence interval: 23.5-61.1%). A total of 20 adenomatous polyps were found in 12 patients. Seven polyps were 5 mm or more in size. CONCLUSIONS: We conclude that in patients with no history of colonic neoplasia who are 50 yr old, or older, the finding of a normal colonoscopy does not predict diminished risk of neoplasia.

Adenomatous Polyps↗
PubMed1992

[Utility of SCG (screening colonography) and combined sigmoidoscopy-SCG in thorough physical checkups].

Given the increasing incidence of colon cancer in recent years, it is important to establish a diagnostic system for early detection and introduce it into clinical practice. A double contrast examination that uses a disposable tip and tube with an enema reservoir filled with 200 ml of 60 w/v% barium sulfate, known as SCG (screening colonography) was used in this study. In order to assess its utility SCG was performed on 1,554 patients, and 2,004 patients were examined by a within 24 hours combination of sigmoidoscopy and SCG by way of screening for colon cancer. Given the brief duration of SCG, which ranged from 10 to 13 min in most patients in the study, the efficiency of the examinations was considered to be rather high. Furthermore, the barium reached the cecum in as many as 98.7% of the patients. Overall, SCG proved to have an excellent diagnostic capability. Sigmoidoscopy-SCG, on the other hand, detected colon cancer in 114 patients (5.7%) and colon polyps in 658 patients (32.8%). The rates of detection of colon cancers and polyps were higher in the patients who tested positive in immunological fecal examinations for occult blood. Judging from our results, it may be said that for many patients receiving thorough physical checkups to screen for colon cancer, our system will provide for efficient screening whereby patients are first examined for fecal occult blood and those who test positive undergo sigmoidoscopy and SCG within the same day.

Adult↗
PubMed2005

Segmentation and size measurement of polyps in CT colonography.

Virtual colonoscopy is a relatively new method for the detection of colonic polyps. Their size, which is measured from reformatted CT images, mainly determines diagnosis. We present an automatic method for measuring the polyp size. The method is based on a robust segmentation method that grows a surface patch over the entire polyp surface starting from a seed. Projection of the patch points along the polyp axis yields a 2D point set to which we fit an ellipse. The long axis of the ellipse denotes the size of the polyp. We evaluate our method by comparing the automated size measurement with those of two radiologists using scans of a colon phantom. We give data for inter-observer and intra-observer variability of radiologists and our method as well as the accuracy and precision.

Algorithms↗
PubMedDate not supplied

CT colonography using different reconstruction modi.

OBJECTIVE: Performing computed tomography (CT) colonography, we compared different reconstruction modi for the detection of colorectal polyps. METHODS: The CT data of 48 patients using 16-slice helical CT were analysed in axial slices, virtual-endoscopy and colon-dissection modus. RESULTS: The sensitivity (specificity) for the detection of colonic polyps was 94% (80%) if using "colonic-dissection" tool and 89% (80%) if using "virtual-endoscopy" tool. The difference between the virtual endoscopy and colon dissection, considering polyps up to 4.9 mm, was significant. CONCLUSIONS: Reconstruction software colon dissection improves the sensitivity of CT colonography.

Colonic Polyps↗
PubMed1980

Hyperplastic polyps of the large bowel.

One hundred seventy-one hyperplastic colonic polyps were examined and found to be less homogenous histologically than has been generally considered. For example, 13% exhibited adenomatous changes, 7.6% contained Paneth cells, and 3% had distinct stalks. They are at times pedunculated and relatively large; some cannot be distinguished grossly from small sessile polyps of other histological patterns and removal is required for proper identification. Other epithelial polyps of equivalent size were compared with the hyperplastic polyps to determine the frequency of the various types. Hyperplastic polyps comprised 43.5% of all surgically removed epithelial polyps of the colon measuring 5 mm or less.

Adult↗
PubMed1985

Inverted hyperplastic polyps of the colon.

An unusual form of hyperplastic polyp of the colon is described in which endophytic growth can simulate adenoma or carcinoma by penetration of the muscularis mucosae and a complex epithelial growth pattern. These lesions differ clinically from exophytic hyperplastic polyps by being more frequent on the right side than in the left colon and being relatively more common in women.

Adenocarcinoma↗
PubMedDate not supplied

[Hyperplastic polyp of the colon].

On re-examining 477 polyps of the colon obtained by endoscopic polypectomy, the authors describe a type of polyp with they have called hyperplasiogenous. This polyp is characterised by a proliferation of rectilinear glands, divided at their base, forming a connecting spur; this spur may form a more complex alveolar or tubulo-alveolar structure. The glands have cells with a tall, clear cytoplasm and a small, homogeneous nucleus with no irregularities or metaplasia. Endoscopically, they are small, sessile and either the same colour as the mucous membrane or redder. They are located mainly in the rectum and sigmoid colon. They are more frequently found in men and begin to appear after the age of thirty. They are often associated with tumours of the colon. The authors consider possible that the hyperplasiogenous polyp may represent an initial stage of adenoma.

Adult↗
PubMed2001

Chemoprevention of intestinal polyposis in the Apcdelta716 mouse by rofecoxib, a specific cyclooxygenase-2 inhibitor.

Mutations in the human adenomatous polyposis (APC) gene are causative for familial adenomatous polyposis (FAP), a rare condition in which numerous colonic polyps arise during puberty and, if left untreated, lead to colon cancer. The APC gene is a tumor suppressor that has been termed the "gatekeeper gene" for colon cancer. In addition to the 100% mutation rate in FAP patients, the APC gene is mutated in >80% of sporadic colon and intestinal cancers. The Apc gene in mice has been mutated either by chemical carcinogenesis, resulting in the Min mouse Apcdelta850, or by heterologous recombination, resulting in the Apcdelta716 or Apedelta1368 mice (M. Oshima et al., Proc. Natl. Acad. Sci. USA, 92: 4482-4486, 1995). Although homozygote Apc-/- mice are embryonically lethal, the heterozygotes are viable but develop numerous intestinal polyps with loss of Apc heterozygosity within the polyps (M. Oshima et al., Proc. Natl. Acad. Sci. USA, 92: 4482-4486, 1995). The proinflammatory, prooncogenic protein cyclooxygenase (COX)-2 has been shown to be markedly induced in the Apcdelta716 polyps at an early stage of polyp development (M. Oshima et al., Cell, 87: 803-809, 1996). We demonstrate here that treatment with the specific COX-2 inhibitor rofecoxib results in a dose-dependent reduction in the number and size of intestinal and colonic polyps in the Apcdelta716 mouse. The plasma concentration of rofecoxib that resulted in a 55% inhibition of polyp number and an 80% inhibition of polyps > 1 mm in size is comparable with the human clinical steady-state concentration of 25 mg rofecoxib (Vioxx) taken once daily (A. Porras et al., Clin. Pharm. Ther., 67: 137, 2000). Polyps from both untreated and rofecoxib- or sulindac-treated Apcdelta716 mice expressed COX-1 and -2, whereas normal epithelium from all mice expressed COX-1 but minimal amounts of COX-2. Polyps from either rofecoxib- or sulindac-treated mice had lower rates of DNA replication, expressed less proangiogenic vascular endothelial-derived growth factor and more membrane-bound beta-catenin, but showed unchanged nuclear localization of this transcription factor. This study showing the inhibition of polyposis in the Apcdelta716 mouse suggests that the specific COX-2 inhibitor rofecoxib (Vioxx) has potential as a chemopreventive agent in human intestinal and colon cancer.

Animals↗
PubMed2001

CT colonography with teleradiology: effect of lossy wavelet compression on polyp detection--initial observations.

PURPOSE: To assess the consequences of lossy compression on the diagnostic accuracy of CT colonography for detecting colonic polyps. MATERIALS AND METHODS: Helical CT images of cleansed colonic segments were evaluated. Source images were compressed to 1:1, 10:1, and 20:1 ratios with lossy wavelet compression. Two independent readers blinded to corresponding colonoscopic results analyzed 144 randomly ordered colonic segments in multiplanar and volume-rendered endoscopic views. Sensitivity, specificity, and receiver operating characteristic curves were generated for each compression ratio on the basis of expressed confidence in lesion presence. Similar analyses were performed to assess distention and bowel preparation adequacy and evaluation time required. RESULTS: Results based on video colonoscopy-confirmed lesions revealed 100% (four of four) sensitivity for lesions larger than 10 mm for compression ratios 1:1, 10:1, and 20:1 for both readers; sensitivities for all lesions smaller than 10 mm were 50%-78%, 38%-67%, and 38%-67% for respective ratios for both readers. Differences in diagnostic performance for each reader across ratios were not significant (P =.30-.99, McNemar test). The time required to evaluate and assess bowel preparation and distention adequacy did not change significantly across ratios. CONCLUSION: On the basis of the patient sample, lossy compression of transverse source images to at least a 20:1 ratio did not adversely affect diagnostic performance or evaluation time for CT colonography.

Aged↗