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At least 919 records · Page 51Linked to original sources
PubMed1990

Histamine augments colonic secretion in guinea pig distal colon.

We tested the hypothesis that the role of histamine in the control of intestinal secretion is mediated by prostaglandins (PGs). The effects of histamine on ion transport were examined in muscle-stripped sheets of mucosa/submucosa set up in flux chambers. Histamine evoked a transient concentration-dependent increase in short-circuit current (Isc) that was reduced by the Cl- transport inhibitor bumetanide. Histamine also caused the release of PGE2. The Isc response to histamine was reduced by indomethacin and piroxicam, which block PG formation, but not by nordihydroguaiaretic acid, which prevents production of lipoxygenase products. 2-Methylhistamine, but not dimaprit, evoked a concentration-dependent increase in Isc. The Isc response to histamine was reduced by the H1-blocker pyrilamine, but not by the H2-antagonist cimetidine. In addition to its direct effect, histamine augmented the responses of endogenously released neurotransmitters with and without indomethacin and hexamethonium. Tetrodotoxin (TTX) reduced the Isc response to 10(-3) M histamine. In the presence of TTX, exogenous histamine amplified the responses to PGs, vasoactive intestinal polypeptide, 2-chloroadenosine, bethanechol, and carbachol. These results suggest that histamine acts at H1-receptors on cells within the gut to mediate intestinal Cl- secretion in part by releasing PGs and by augmenting the actions of endogenously released neurotransmitters. Our results indicate that histamine has a role in the regulation of colonic transport function.

2-Chloroadenosine↗
PubMed1980

Heritable colonic cancer syndromes: induction of anchorage-independence in dermal cultures derived from patients with adenomatosis of the colon and rectum.

After exposure to the mutagen, ethylmethanesulfonate (EMS), or the carcinogen, urethane (UR), anchorage independence was observed in cultures derived from normal skin biopsies from patients with the heritable cancer syndrome, adenomatosis of the colon and rectum (ACR). Such colonies from methylcellulose suspension cultures did not produce tumors in athymic mice. Dissociation of growth in suspension from tumorigenicity was considered to be consistent with the hypothesis that a series of somatic mutation-like events occur in carcinogenesis. Such ACR cells should prove to be useful in studies on the genetic predisposition to cancer.

Adenoma↗
PubMed2000

Uptake of long-circulating immunoliposomes, directed against colon adenocarcinoma cells, by liver metastases of colon cancer.

Radiolabeled ([3H]cholesteryloleyl ether) immunoliposomes directed against rat colon adenocarcinoma CC531 cells were prepared by random coupling of a tumor cell-specific antibody, CC52, via a thio ether bond. In vitro binding experiments demonstrated a saturable and specific interaction of CC52-immunoliposomes, which could be inhibited by free non-coupled CC52 but not by irrelevant antibodies. The in vivo targeting potential of CC52-immunoliposomes, which were pegylated to achieve prolonged circulation times, was tested in an established rat liver CC531 metastasis model. Twenty-four hours after injection of the liposomes, 25% of the CC52-immunoliposomes were still present in the blood, which was comparable with the control liposomes (either with or without antibody). Liposomes were mainly taken up from the blood by the liver and the spleen, although hepatic uptake of the immunoliposomes was higher and splenic uptake was lower as compared to liposomes without antibody. Within the metastatic tumor nodules in the liver, uptake of both the CC52-immunoliposomes and non-specific immunoliposomes was significantly higher than that of control liposomes without antibody. Visualization of fluorescently or gold labeled CC52-immunoliposomes revealed that, although targeting to liver metastases was achieved, the immunoliposomes were mostly not associated with tumor cells but rather localized in tumor associated cells, probably macrophages.

Adenocarcinoma↗
PubMed2003

Gene mutations in advanced colonic polyps: potential marker selection for stool-based mutated human DNA assays for colon cancer screening.

The detection and removal of advanced colonic polyps (ACPs) can help prevent the development of colorectal cancer. A set of DNA mutations known to be associated with colorectal carcinoma was tested against resected ACPs to determine the set s potential utility as a marker panel for ACPs. A sensitive mutation marker panel could be used by stool-based assays that look for mutated human DNA to detect the presence of ACPs. DNA from 32 ACPs = 1.0 cm in diameter was amplified and tested for 19 colorectal cancer associated DNA mutations and for deletions in BAT-26 (microsatellite instability). One or more mutations were identified by microsequencing in 28 of the 32 ACPs (88%). Mutations were identified in k-ras (59%), APC (33%), and p53 (22%). BAT-26 mutation, a marker for microsatellite instability, was not identified. Stool DNA based assays that can identify these mutations may significantly increase the identification of patients with potentially premalignant ACPs for evaluation and treatment by colonoscopy.

Adult↗
PubMed1991

[Colonic polyposis and cancers of the colon. Molecular markers, predisposition and diagnosis of familial forms].

Five to 10% of colorectal carcinomas are obvious inherited familial syndromes. The inherited molecular basis of the predisposition is uniformly present in normal cells of such patients. The identification of the genes underlying cancers, performed with the intent to clone, would first serve as a basis for a pre-symptomatic diagnosis. The APC gene, located on the long arm of chromosome 5, is the only molecular target already identified as involved in the predisposition to familial adenomatous polyposis. Other genes are involved in the progression of sporadic colorectal neoplasias. Their identification would help in the comprehension of colonic carcinogenesis. Molecular analysis of these markers determines improvements in the management of a frequent and most severe disease, in which progress in screening and treatment has been very slow over the past twenty years.

Adenomatous Polyposis Coli↗
PubMed1991

[Establishment of transplantable human colon cancer cell lines, chemosensitivity of colon carcinomas and the serially transplantable strains with MTT assay].

Three human colon carcinoma xenografts serially transplantable into nude mice were established and named Co-6, Co-7, and Co-8. The chemosensitivity of these stains were assessed by MTT assay of the fresh surgical specimens (primary MTT assay) and the serially passaged xenografts (xenografts MTT assay), in vivo chemosensitivity test in nude mice (nude mouse system) and clinical responses. Drugs used for the experiments are mitomycin C (MMC), adriamycin (ADM), 5-fluorouracil (5-FU) and cisplatin (DDP). The primary MTT assay revealed true negative with MMC and 5-FU on Co-7 and Co-8 cases. The chemosensitivity of the tumor cells seemed to be increased in the xenografts MTT assay and nude mouse system, in which MMC and DDP were evaluated to be positive on Co-6 and Co-7. However, the chemosensitivity pattern of the tumor cells seemed to be stable in these chemosensitivity tests, indicating better to choose the agent with the highest inhibition rate among various tested agents, even when none have an inhibition rate equal to or more than 50%.

Animals↗
PubMed1990

Displacement of the large colon associated with nonsurgical correction of large-colon entrapment in the renosplenic space in a mare.

Nonsurgical correction of a renosplenic entrapment of the large colon was attempted in a mare, using a rolling technique. After correction, the mare had initial improvement in clinical signs, but later developed signs of abdominal discomfort. A ventral midline celiotomy was performed, and a pelvic flexure impaction and large intestinal volvulus were found and corrected.

Animals↗
PubMed1990

[Injuries of the sigmoid colon following radiation therapy of carcinoma of the uterine cervix--a method of estimating the radiation dose to the sigmoid colon].

Grade 2 or 3 injuries of the sigmoid colon were observed in 4 out of 42 patients with carcinoma of the uterine cervix who were treated by radiation therapy. The irradiation was planned as the combination of the external irradiation (whole pelvic 30 Gy and 20 Gy with central shielding by 25 fractions, 5 weeks) and the intracavitary irradiation (RALS, 19 Gy at point A by 3 fractions). To analyze the causes of the radiation sigmoiditis, we have investigated the following factors: age, dose at point A, dose at point C, grade of tandem dislocation, uterine angle, obesity score, evidence of previous surgery to the pelvic cavity and hypertension. The dose at point C and the grade of tandem dislocation were determined from the confirming X-Ps at RALS therapy and external irradiation. The superimposition of these films was performed with corrections for the angle between the projection direction of the X-Ps and the vertical magnification factor of the central shielding area. Point C was defined as a point 2 cm anterior to the intersection of the tandem axis and a curvilinear line 1 cm outside from the margin of central shield on the X-Ps. Grades of tandem disclocation were decided as the number of tandem tips which were outside of the central shielding area on X-Ps. As the results, the doses at point C showed very high statistical significance (p less than 0.001) with the evidence of radiation sigmoiditis. All the cases with radiation sigmoiditis were received over 1290cGy at point C. Age had also some significance (p less than 0.05) with radiation sigmoiditis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1989

Proteins excreted by primary human colon carcinoma cells (SW 480) promote spreading and growth of metastatic human colon carcinoma cells (SW 620) in serum-free medium.

The growth behavior of the two human colon tumor cell lines (SW 480, primary and SW 620, metastatic), originating from the same patient, was studied in six different serum-free media (SFM) [GF3, Chee's essential medium plus insulin, transferrin and selenium; GF3F, GF3 plus fetuin; GF4, GF3 plus linoleic acid-BSA; GF5, GF4 plus fetuin; GF5E, GF5 plus EGF; GF5T, GF5 plus triiodothyronine]. SW 480 grew in all of the SFM. In contrast, SW 620 grew only in four SFM. The cells did not grow in GF3 and GF4. When grown in SFM, SW 480 attached much more firmly to the dishes than SW 620 as determined by the time required to detach the cells with trypsin-EDTA (SW 480, greater than 20 min and SW 620, less than 5 min). It was speculated that SW 480 cells excrete proteins in SFM which influence attachment and growth of the cells. Growth behavior of SW 480 cells which did not grow in GF3, was studied using GF3 medium and SW 480 substratum dishes. SW 620 cells readily attached to the SW 480 substratum dishes and grew. Furthermore, when SW 620 cells were grown on substratum prepared from serum-supplemented medium incubated in the absence of cells (serum substratum), the cell growth was comparable to the cell growth on SW 480 substratum in GF3. Substratum from SW 480 cells and the serum substratum were compared for their components using SDS-PAGE system. The SW 480 substratum contains many more components than serum substratum. A protein band at 60 kD appears to be common in both SW 480 and serum substrata.

Adenocarcinoma↗
PubMed1983

[Methods for the early detection of colonic polyps and colonic cancers].

The dramatically rising incidence of colorectal cancer and the fact that survival rates can only be improved by earlier diagnosis call for increased efforts aimed at early detection of colonic neoplasias. Present diagnostic methods--occult blood testing, digital exam, rigid and flexible sigmoidoscopy, double contrast barium enema and colonoscopy--are analyzed with regard to diagnostic yield, time requirement and patient acceptability. Flexible sigmoidoscopy has proved to be of high diagnostic value, to take relatively little time and to cause only minimal patient discomfort. It will therefore gradually replace rigid sigmoidoscopy. Various populations at risk for colorectal cancer are outlined and appropriate diagnostic screening methods are described. Finally, a plan for monitoring of the normal risk population is proposed.

Colonic Neoplasms↗
PubMed1994

[Surgical treatment of colonic fistulas with descending colon].

Radical operations were conducted on 50 out of 78 patients with coloperineal and colovaginal fistulas consequent upon resection of the colon and bringing out its segments into the anal canal. The fistulas recurred in 10 patients. Individual choice of the operative method and development of a system of pre-, intra-, and postoperative special methods should reduce the incidence of recurrences after such operations.

Anal Canal↗
PubMed1998

[Biliary colonic ileus: an unusual cause of colonic obstruction].

We report a rare case of colonic gallstone obstruction in a patient with cholecystocolic fistula. Diagnosis of this condition is usually difficult and only achieved at surgery. We review the radiological findings, particularly the CT findings, helpful for diagnosis: ectopic gallstone, biliary gas and fistula. Early preoperative diagnosis could reduce morbidity and mortality. Treatment is surgical with enterolithotomy. There is some controversy over the need to repair the fistula.

Aged↗