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PubMedDate not supplied

Correlations between colonic wall thickening in patients with virally induced cirrhosis on CT and clinical status.

PURPOSE: The purpose of this work was to determine the frequency and CT imaging spectrum of colonic wall thickening and correlate these with the clinical severity of virally induced cirrhosis. METHOD: Fifty-nine patients were identified with virally induced cirrhosis and no other causes of colonic wall thickening. The abdominal CT scans of these patients were retrospectively reviewed by two radiologists to determine the presence of colonic wall thickening from the ascending colon to the descending colon, to assess the segmental distribution, and to correlate these findings with the clinical status assessed by Child-Pugh classification, presence of ascites, splenic volume index, varices score, and serum albumin levels. RESULTS: Colonic wall thickening was identified in 18 (31%) patients. The frequency of the affected distribution of colonic wall thickening was as follows: ascending colon in 17 (29%) patients, transverse colon in 11 (19%) patients, and descending colon in 7 patients (12%). The ascending colon was the most common site of colonic wall thickening (p < 0.001). Ten (17%) patients had multisegmental distributions. Colonic wall thickening had a statistically significant association with Child-Pugh grades A, B, and C (p < 0.0001), presence of ascites (p < 0.0004), splenic volume index (p = 0.0026), varices score (p < 0.0001), and serum albumin levels (p = 0.0364). The segmental distribution of wall thickening significantly correlated with Child-Pugh grades A, B, and C (p = 0.0005), presence of ascites (p < 0.001), varices score (p < 0.0001), serum albumin levels (p < 0.0001), and splenic volume index (p = 0.0135). CONCLUSION: Colonic wall thickening occurs commonly in patients with virally induced cirrhosis. The presence and number of colonic wall thickening were correlated with the grading of the severity of cirrhosis.

Adolescent↗
PubMed1989

Penetrating injuries to the colon: analysis by anatomic region of injury.

The preferred method for the treatment of penetrating injuries to the colon remains a source of controversy. In our retrospective review of 65 patients with penetrating colon injuries, 33 patients were managed by colostomy formation, 30 were treated by primary repair, and two had exteriorized repair with early return to the abdominal cavity (drop back). The anatomic location of injury was ascending colon in 19 (29%), transverse colon in 20 (31%), descending colon in 22 (34%), and multiple sites in four (6%). The average penetrating abdominal trauma index (PATI) was 24 (ascending colon injuries, 23; transverse colon, 26; descending colon, 24; and multiple colon sites, 28). Overall septic morbidity was 15/65 (23%). Colostomy closure was later done in 32/33 (97%), with a morbidity of 7/32 (22%). The mean length of hospital stay for primary repair was ten days and for colostomy (including both required hospital stays), 26 days (P less than .05). These data suggest that primary repair is as safe as colostomy formation for the management of penetrating colon injuries, regardless of anatomic site of injury.

Adult↗
PubMed2001

Ultrasonographic examination of the caecum and the proximal and spiral ansa of the colon of cattle.

The large intestine of 10 cows was examined from the right abdominal wall with a 3.5 MHz linear transducer. The cows were then slaughtered, and the organs were re-examined in a water bath. The caecum was visualised from the middle region of the abdominal wall. It ran caudo-cranially, varied in diameter from 5.2 to 18.0 cm and was situated immediately adjacent to the abdominal wall. The lateral wall of the caecum appeared as a thick, echogenic, crescent-shaped line. It could be visualised as far cranially as the 12th intercostal space. Although its junction could not be identified, the proximal ansa of the colon was recognised on the basis of its anatomical position and its diameter, which was smaller than that of the caecum. The spiral ansa of the colon and the descending colon were situated dorsal to the caecum and could be identified by moving the transducer horizontally along the abdominal wall to the last rib. The spiral ansa of the colon was situated ventral to the descending colon, and its walls appeared as thick echogenic lines. In a contracted state, the spiral colon had the appearance of a garland.

Animals↗
PubMedDate not supplied

Colosigmoid junction: a study of its functional activity with identification of a physiologic sphincter and involvement in reflex actions.

The colosigmoid junction (CSJ) marks the termination of the descending colon (DC) and the beginning of the sigmoid colon (SC); it is a fixed area in the retroperitoneum. At this site where two functionally different areas meet, we hypothesized the presence at the CSJ of a physiologic sphincter that regulates the passage of gut contents from the DC to the SC. This hypothesis was investigated for this communication. Eight subjects (mean age 36.6 +/- 4.7 SD years, 6 women) were studied during surgical repair of incisional hernia or laparotomy. The pressure responses of the CSJ to individual distension of the DC and SC were recorded. A balloon-ended tube was introduced per annum to lie in the DC or SC, and the pressure in the DC, CSJ, and SC was measured by saline-perfused catheters. To study whether the CSJ response to individual DC or SC distension was a direct or reflex action, the test was repeated in six of eight patients after separate anesthetization of the DC, CSJ, and SC. The CSJ had a higher pressure than that of the DC or SC; the high-pressure zone measured a mean of 2.1 +/- 0.9 cm. High-volume DC distension effected a significant DC pressure rise (p <.001) and a CSJ pressure decline (p <.05), which lasted a mean of 7.2 +/- 1.2 s. In contrast, the CSJ responded to big volume SC distension by significant pressure elevation (p <.001) which was also momentary. Small volume distension of the DC or SC effected no significant CSJ pressure response (p >.05). The CSJ pressure did not respond to distension of the anesthetized DC or SC. Likewise, the anesthetized CSJ did not react to DC or SC distension. When the test was repeated using saline instead of xylocaine, the CSJ pressure response was similar to that without saline injection. The CSJ is a high pressure zone with a measurable length. It reacts to DC or SC balloon distension by dilatation or narrowing, respectively. These findings presumably denote the existence of a "physiologic sphincter" at the CSJ, which appears to regulate the passage of colonic contents to the SC. We postulate that the CSJ pressure response to DC or SC distension is reflex and mediated through the "colosigmoid reflexes." The role of the colosigmoid sphincter and reflexes in colonic motility disorders remains to be investigated.

Adult↗
PubMed1987

Age-dependent shift-to-the-right in the localization of colorectal adenomas.

The age-dependent prevalence and topographical distribution of colorectal adenomas was investigated in 1006 unselected autopsies (554 males and 452 females) in Mainz, FRG. In 200 out of 1006 autopsies (19.8%) a total of 498 adenomas of the large intestine were detected. The percentage of patients with adenomas increased continuously with age. Only 6% of all adenomas were localized in the caecum and 8% in the rectum, whereas all the other adenomas were distributed rather evenly throughout the ascending colon (23%), the transverse colon (25%), the descending colon (15%) and the sigmoid colon (23%). Analyzing the topographical distribution of adenomas for definite age groups (40-59, 60-69, 70-79 and 80-99 years of age), it became evident that the topographical distribution is not constant, but shows an age-dependent shift-to-the-right, i.e. with advancing age an increase in the relative frequency of adenomas in the proximal colonic segments (from caecum to transverse colon) and a decrease in the distal segments (from descending colon to rectum). This shift to the right, which evolves continuously from the youngest to the oldest age group, results from a disproportionate increase in the absolute number of adenomas in the proximal colonic segments when compared with the distal segments. The age-dependent shift-to-the-right of colorectal adenomas provides an important confirmation of the adenoma-carcinoma sequence, but cannot be explained by current concepts concerning the aetiology of colorectal adenomas and carcinomas.

Adenoma↗
PubMed1983

Gut-associated lymphoid tissue and dimethylhydrazine-induced colorectal carcinoma in the Wistar/Furth rat.

Although gut-associated lymphoid tissue in the form of discrete lymphoid patches (LP-GALT) in mammalian intestine in most prominent in the distal ileum, appendix, and, in some species, the cecal appendage, LP-GALT can be found throughout the intestinal tract. LP-GALT appears as single or multiple subepithelial lymphoid follicles covered by a specialized, structurally unique epithelium. In the colon of the Wistar/Furth (W/Fu) rat, LP-GALT appears as aggregates of follicles, or lymphoid patches, that can be detected macroscopically. We studied the relationship between 1,2-dimethylhydrazine- (DMH) induced colon carcinomas and the lymphoid patch associated epithelium in these animals. In addition, we defined the normal distribution of colonic lymphoid patches in both DMH-treated and control rats. Patches were found macroscopically and confirmed by histologic examination at five constant sites: lower pole of cecum, proximal ascending colon, the major colonic flexure, mid descending colon, and the rectosigmoid. There are also the predominant sites of DMH induced carcinomas in W/Fu rats. In 120 DMH-treated animals, 109 colon carcinomas were found. Eight percent were in the lower pole of the cecum, 56% in the proximal ascending colon, 16% at the major flexure, 15% in the mid descending colon, and 5% in the rectosigmoid. Lymphoid patches could often be detected histologically in association with DMH-induced tumors. The depth of tumor invasion was found to correlate inversely with our ability to identify tumor-associated lymphoid patches suggesting that tumors arising at the anatomical sites were lymphoid patches occur progressively destroyed them. Of colon tumors confirmed histologically to be associated with lymphoid patches, 88% were superficial lesions confined to the submucosa and 12% were more extensive but confined to the bowel wall. No lymphoid patches could be found associated with tumors that extended through the bowel wall. Thus, DMH-induced colon carcinomas in W/Fu rats arise at sites containing preexisting LP-GALT with associated specialized epithelium.

Animals↗
PubMed2001

Schwannomas in the colon and rectum: a clinicopathologic and immunohistochemical study of 20 cases.

Schwannomas of the colon and rectum are uncommon and incompletely characterized tumors, and only a small number of cases have been reported. This study was undertaken to determine the clinicopathologic profile of such tumors. A total of 20 colorectal schwannomas were identified and analyzed in a review of 600 mesenchymal tumors of the colon and rectum from the files of the Armed Forces Institute of Pathology. The schwannomas occurred equally in men (n = 9) and women (n = 11) in a wide age range (18-87 years; median age 65 years). The most common location was cecum (n = 7), followed by sigmoid and rectosigmoid (n = 6), transverse colon (n = 3), descending colon (n = 2), and rectum (n = 1); the location of one tumor had not been specified. The tumors commonly presented as polypoid intraluminal lesions, often with mucosal ulceration. Rectal bleeding, colonic obstruction, and abdominal pain were the most common presenting symptoms. The most common histologic variant (n = 15) was a spindle cell schwannoma with a trabecular pattern and vague or no Verocay bodies. These tumors ranged from 0.5 to 5.5 cm in diameter. A lymphoid cuff with germinal centers typically surrounded these tumors and focal nuclear atypia was often present, but mitotic activity never exceeded 5 per 50 HPF. All four epithelioid schwannomas occurred in the descending colon or sigmoid, three of them as small submucosal tumors. There was one plexiform schwannoma in the sigmoid composed of multiple nodules of prominently palisading schwann cells similar to those seen in conventional soft tissue schwannomas. All tumors studied were strongly positive for S-100 protein and also for low affinity nerve growth factor receptor (p75), collagen IV, and GFAP. Three tumors had CD34-positive cells, but all were negative for CD117 (KIT), neurofilament proteins, smooth muscle actin, and desmin. The percentage of MIB-1-positive cells was usually less than 1% and never higher than 3%. Colorectal schwannomas behaved in a benign fashion with no evidence of aggressive behavior or connection with neurofibromatosis 1 or 2, based on follow-up information on 18 patients.

Adolescent↗
PubMed1985

[Age-related changes in adenylate cyclase activity, lipid composition and lipid peroxidation in rat intestinal mucosa: comparison with the frequency of spontaneous tumors].

The study used 3, 7, 16 and 22 month-old male rats bred at the animal farm of the Institute. Identical age-related changes were established in the level of free cholesterol, its esters, free cholesterol/phospholipids and sphingomyelin/lecithin ratios in ascending and descending colon mucosa. Unlike descending colon mucosa, the basal and hormone-stimulating activity of adenylate cyclase and rate of lipid peroxidation in the mucosa of the ascending colon of 22 month-old animals were lower than in 16 month-old rats. The results are compared with the available data on the predominant localization of spontaneous tumors in the proximal (ascending) part of rat's intestine.

Adenylyl Cyclases↗
PubMed1991

Inhibitory neuropeptides and intrinsic inhibitory innervation of descending human colon.

The effects of aging on inhibitory neuropeptide concentrations and intrinsic inhibitory innervation of circular muscle were investigated using normal descending colon obtained at surgery. Immunoreactive vasoactive intestinal peptide, peptide histidine-methionine, met5-enkephalin, neuropeptide Y, and somatostatin were extracted from specimens of muscularis externa (patient ages: 19-84 years) and measured by radioimmunoassay. Intracellular electrical activity was recorded from strips of circular muscle (patients ages: 49-84 years) using glass microelectrodes; inhibitory junction potentials were evoked by electrical field stimulation. There were no significant differences (t tests: P greater than 0.05) between neuropeptide concentrations in patients less than 70 years old (N = 28) compared to patients greater than or equal to 70 years old (N = 12). However, the amplitude of inhibitory junction potentials declined with increasing patient age (r = -0.58, P = 0.02, N = 16), with no change in resting membrane potentials (r = 0.22; P greater than 0.05). The decline in amplitude in women (r = -0.68, P = 0.03, N = 9) preceded the decline in men (r = -0.62, P = 0.10, N = 7). Age-related decline in inhibitory junction potentials could be related to decreased: density of inhibitory nerves, release of inhibitory neurotransmitter, density of binding sites for inhibitory neurotransmitter on smooth muscle, or a combination thereof. Alternatively, this decline might represent a change in interaction of inhibitory neurotransmitter with the smooth muscle membrane, such as a change in coupling of binding site with the potassium channel, decreased number of potassium channels, or altered permeability of the potassium channel.

Adult↗
PubMed1996

Colonoscopic screening for families of patients with colorectal cancer.

We conducted a prospective study using primary colonoscopy in the families of patients with surgically treated colorectal cancer (CRC) to evaluate its feasibility as a screening method for CRC. The presumed detection sensitivity of sigmoidoscopy in this group was also evaluated. Over a 3-year period, 142 first-degree relatives (73 men and 69 women) of 117 patients with CRC participated in this colonoscopic screening study. The average age at presentation for examination was 49.1 years (range, 31-79 yr). Forty-nine patients had adenomatous polyps (AP) and four patients had cancer, yielding a frequency of 37% (53/142). Thirty-six family members were under 40 years of age, eight of whom had AP. In total, there were 111 AP and four invasive cancers; 42% (48/111) of AP and 75% (3/4) of cancers were beyond the reach of conventional flexible sigmoidoscope. Of 53 patients with AP or cancer in the large bowel, 36 had AP or cancer in the distal colon (rectosigmoid region and descending colon), 15 (42%) of whom were found to have at least one AP or cancer in the proximal colon (proximal to the descending colon). The remaining 17 patients' lesions were confined to the proximal colon, and would not have been detected with a flexible sigmoidoscope. Sigmoidoscopy in high-risk patients with neoplasm in the large bowel has a sensitivity of 68%. We conclude that a vigorous surveillance program using primary colonoscopy should be set up for those who are first-degree relatives of patients with CRC. Routine examination should start at the age of 40, and the entire colon should be evaluated.

Adult↗
PubMed1999

Adult colonic intussusception caused by malignant tumor of the transverse colon.

Adult colonic intussusception is rare and often originates from neoplasms. In emergency situations it can be difficult to diagnose. Our aim was to show how the integration of readily available diagnostic means in emergency situations can help in making a correct diagnosis of this disease. A 68-year old male patient presented with vomiting and abdominal pain. The abdomen was distended, with pain to palpation in the left quadrants without a mass. Plain radiographs of the abdomen showed a large amount of gas in the small bowel and in the right and transverse colon. A barium enema demonstrated an endoluminal filling defect in the descending colon. Abdominal ultrasonography revealed the presence of intraperitoneal fluid and thickened left colonic wall at the site of the lesion, with an aspect of a "double ring" consistent with intussusception. A solid formation was also revealed at a point distal to the thickened colonic wall. At emergency laparotomy an approximately 8-cm-long mass was palpable through the left colon. A colostomy was fashioned, and subsequently colonoscopy revealed the presence of a left colon tumor. At the subsequent operation an invagination of the left transverse colon into the descending colon was confirmed. The left transverse and descending colon were resected with high ligation of the left colic artery. Macroscopic examination of the invaginating head showed a vegetating transverse colon neoplasm. We conclude that in emergency settings the association of readily available diagnostic means such as plain abdominal radiography, water soluble contrast enema and ultrasonography may yield reliable information for diagnosing colonic intussusception.

Adenocarcinoma, Mucinous↗
PubMedDate not supplied

Colonoscopic impaction in left colon strictures resulting in right colon pneumatic perforation.

Colonic perforation during flexible colonoscopy is a rare but recognized complication. We reviewed 4,593 colonoscopies performed from 1984 to 1989. The perforation rate for diagnostic colonoscopy was 0.17% (6/3,538) and for therapeutic colonoscopy it was 2% (21/1,055). Four perforations of the right colon occurred at a site proximal to the level of the impacted colonoscope. The lesions being evaluated were obstructive in nature: two diverticular strictures (sigmoid colon), one ischemic stricture (descending colon), and one annular carcinoma (descending colon). The four perforations occurred in the right colon and manifested as distension with pneumoperitoneum or retroperitoneal emphysema. Operative management included total abdominal colectomy in two patients (ileoproctostomy in one and ileostomy in one) and right colectomy in two. Outcome was favorable in all cases.

Aged↗
PubMed1988

Effect of chemical ablation of myenteric neurones on intestinal cell proliferation.

The duodenum or descending colon of male Wistar rats (average weight 60 g) was treated by a serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with 0.9% (physiological) saline. The rats were allocated to four groups: Group DC (N = 8) in which the duodenum was treated with physiological saline; Group DB (N = 8) in which the duodenum was treated with BAC; Group CC (N = 7) in which the descending colon was treated with physiological saline and Group CB (N = 7) in which the descending colon was treated with BAC. After treatment, the animals were followed up for 5 months. At the end of the experiment, the animals were injected intraperitoneally with vincristine sulphate before sacrifice. Three segments were removed from the duodenum and descending colon for neuronal counting, catecholamine and serotonin measurements and morphokinetic studies of the epithelium. The following results were obtained: (1) there was a significant reduction in neurone number in the myenteric plexus of segments treated with BAC; (2) in the denervated intestinal segments, catecholamine levels were unchanged whereas serotonin levels were increased; (3) epithelial hyperplasia was observed in the denervated duodenum and descending colon; and (4) crypt cell production rate in the duodenum was similar in groups DC and DB but was significantly increased in the descending colon in group CB as compared with controls (CC). The present findings indicate that selective myenteric neuronal denervation caused by benzalkonium chloride plays a causative role in the hyperplasia and crypt cell production rate of the intestinal epithelium (duodenum and descending colon). These changes are probably induced by functional imbalance by the surviving neuronal elements in the gut, implicating neurotransmitters such as acetylcholine, noradrenaline, serotonin, somatostatin and vasoactive intestinal peptide.

Animals↗
PubMed2004

The defecation reflex in rats: fundamental properties and the reflex center.

While pharmacological and physiological studies in rats are now increasing, physiological properties of their defecation have been scarcely investigated. This study was performed to define the properties of defecation in decerebrate rats, with special reference to the pontine defecation reflex center, which has been postulated in dogs. Intraluminal pressure was recorded from the colon and rectum with balloon-pressure transducer method using balloons of 15-20 mm in length and 0.1-0.3 ml in volume. Distention of a balloon in the descending colon and rectum with an additional injection of 0.03-0.1 ml air induced propulsive contractions on the descending colon and rectum. The mean of threshold pressures to induce propulsive contraction was 17.0 +/- 5.8 mm Hg (mean+/-S.E.) in the proximal part and 18.3 +/- 3.3 mm Hg in the distal part of the descending colon, and 11.8 +/- 1.3 mm Hg in the rectum. The maximum amplitude of propulsive contractions was 55 mm Hg in the rectum, 47 mm Hg in the distal part of the descending colon and 38 mm Hg in the proximal part. Similar colorectal propulsive contractions were produced by gastric distention (5-10 ml, 20-30 mm Hg) and electrical stimulation of the anal canal. Contrarily, spontaneous contractions of the proximal colon were suppressed by rectal distention and anal-canal stimulation. These results suggest that the descending colon and rectum, but not the proximal colon, were innervated by the pelvic afferent and efferent fibers mediating the defecation reflex. Pontine transection at the cerebellar peduncle level abolished colorectal propulsive contractions induced by distention of the stomach, descending colon and rectum, and stimulation of the anal canal, although much smaller contractions were still induced after the pontine transection. These results suggest that the pontine defecation reflex center exists and works in rats, as in dogs.

Animals↗
PubMed1994

Stimulating action of KW-5139 (Leu13-motilin) on gastrointestinal motility in the rabbit.

1. The gastrointestinal motor stimulating action of the motilin analogue, KW-5139 (Leu13-motilin), was investigated both in the anaesthetized rabbit and in rabbit isolated smooth muscle tissues. 2. KW-5139 (0.3-10 micrograms kg-1, i.v.) produced motor stimulating actions in the gastric antrum, ileum and descending colon, the excitatory responses of which were initiated at the same time but declined with different time courses. The rank order of the excitatory response was: descending colon > or = gastric antrum >> ileum. 3. Atropine (1-3 mg kg-1, i.v.) or naloxone (1 mg kg-1, i.v.) completely suppressed the excitatory response to KW-5139 in the gastric antrum, but only partially attenuated that in the descending colon. This suggests that the mechanism of the excitatory response is different in the gastric antrum and the descending colon, and that cholinergic neural pathway is involved in the response of the gastric antrum. 4. KW-5139 (0.1 nM-1 microM) caused concentration-dependent contractions of the gastric antrum, duodenum, jejunum, ileum and the descending colon in vitro. In the rabbit intestine, the contractile response to KW-5139 was strongest in the duodenum and weakest in the ileum. 5. The contractile response to KW-5139 in the intestinal segments were not affected by tetrodotoxin, but were decreased by verapamil, or pretreatment with a high concentration of porcine motilin, confirming the involvement of motilin receptors in the response to KW-5139. 6. The present results suggest that the rabbit is a suitable species for the investigation of motilin on gut motility, because of the high responsiveness of the descending colon as well as the upper gastrointestinal tract.

Animals↗
PubMed1997

Melatonin and colon carcinogenesis: I. Inhibitory effect of melatonin on development of intestinal tumors induced by 1,2-dimethylhydrazine in rats.

The effect of pineal indole hormone melatonin on colon carcinogenesis was firstly studied in rats. Two-month-old outbred female LIO rats were weekly exposed to 15 (experiment 1, groups 1 and 2) or to five (experiment 2, groups 1 and 2) s.c. injections of 1,2-dimethylhydrazine (DMH) at a single dose of 21 mg/kg of body weight. From the day of the first injection of the carcinogen DMH, the rats from groups 2 (experiments 1 and 2) were given melatonin five days a week during the night-time (from 18:00 h to 8:00 h), dissolved in tap water at 20 mg/l. The experiment was finalized in 6 months after the first injection of DMH. In both experiments the majority of tumors were localized in the descending colon. Tumors of the small intestines developed only in rats from experiment 1. Total incidence of colon tumors as well as tumors in different parts of the colon and the mean number of tumors per rat were much higher in rats from both groups in experiment 1 than that in rats from experiment 2. In experiment 1 melatonin failed to influence the total incidence of colon tumors. However, incidence of carcinomas in the ascending colon was significantly reduced (P < 0.01). The multiplicity of total colon tumors per rat, as well as the mean number of tumors, ascending and descending colon per rat, was also decreased under the influence of melatonin (group 2 vs group 1, P < 0.01). In the same experiment, melatonin slightly decreased the depth of tumor invasion and increased number of highly differentiated colon carcinomas induced by DMH. The percentage of small tumours in the descending colon among rats from group 2 was higher than that of group 1. Treatment with melatonin was also followed by a decrease in the multiplicity of DMH-induced tumors of the duodenum (group 2 vs group 1, P < 0.05) and by a decrease in the incidence of jejunum and ileum tumors (group 2 vs group 1, P < 0.05). In experiment 2, the inhibitory effect of melatonin on DMH-induced colon carcinogenesis was much more expressed than that in experiment 1. Thus, in group 1 the incidence of total colon tumors, ascending and descending colon tumors, was significantly decreased in comparison with group 2; also melatonin reduced the number of tumors per rat in the ascending and descending colon. The number of colon tumors that invaded only mucosa was significantly higher in group 2 than in group 1, P < 0.05. The ratio of highly differentiated tumors was increased (P < 0.05) and the ratio of low-differentiated tumors was decreased (P < 0.05) in rats exposed to melatonin (group 4) as compared with group 3. The number of large size tumors in the ascending and descending colon was decreased whereas the number of small size tumors (<10 mm2) was increased in those parts of the colon that were under the influence of melatonin in experiment 2. Thus, our results demonstrate the inhibitory effect of melatonin on intestinal carcinogenesis induced by DMH in rats.

1,2-Dimethylhydrazine↗
PubMed2003

Abnormal levels of neuropeptide Y and peptide YY in the colon in irritable bowel syndrome.

OBJECTIVE: To assess the levels of gut peptides involved in gastrointestinal motor, secretory and sensory function in colonic biopsies in irritable bowel syndrome (IBS) patients and healthy controls. METHODS: We studied 34 patients with IBS and 15 subjects without gastrointestinal symptoms. The predominant bowel pattern in the IBS patients was constipation in 17 patients (IBS-C) and diarrhoea in 17 patients (IBS-D). With radioimmunoassay, the levels of vasoactive intestinal peptide (VIP), substance P, neuropeptide Y (NPY) and peptide YY (PYY) were analysed in biopsies from the descending colon and ascending colon obtained during colonoscopy. RESULTS: The IBS patients had lower levels of PYY in the descending colon than the controls, but the levels in the ascending colon did not differ. The NPY levels were lower in IBS-D than in IBS-C, both in the ascending colon and in the descending colon. Low levels of VIP were more common in IBS patients, but mean levels did not differ between groups. No group differences were observed for substance P. The levels of VIP, substance P and NPY were higher in the ascending colon than in the descending colon, whereas the opposite pattern was seen for PYY. CONCLUSION: IBS patients demonstrate lower levels of PYY in the descending colon than controls. Colonic NPY levels differ between IBS subgroups based on the predominant bowel pattern. These findings may reflect the pathophysiology of IBS and the symptom variation within the IBS population.

Adult↗
PubMedDate not supplied

Histochemical studies of epithelial cell glycoproteins in normal rat colon.

Two general classes of glycoproteins have been identified in the colonic epithelial cells of the Sprague Dawley rat. Glycoproteins belonging to the first of these classes contain sialic acids both with and without side chain o-acyl substituents, abundant o-sulphate ester and 'neutral sugars' (hexose, 6-deoxyhexose or N-acetyl hexosamine residues) with oxidisable vicinal diols and are located in the goblet cells of the descending colon and in goblet cells populating the upper halves of the crypts of the ascending colon. In the descending colon, the sulphosialoglycoproteins in the goblet cells in the base of the crypts contain sialic acids without side chain o-acyl substituents. It appears that as these cells migrate up the crypts, there is o-acylation of the side chains of the sialic acids of the glycoproteins and an increase in the quantity of 'neutral sugars' without a corresponding increase in sialic acid. Glycoproteins with similar properties to those of the goblet cells of the upper halves of the crypts of the descending colon, but containing less sulphate, are found in the goblet cells of the upper half of the crypts of the ascending colon. The second general class of glycoproteins contain sialic acids all, or almost all of which, are substituted at position C8 and only relatively small quantities of sulphate. They are located in the mucous cells of the descending colon, the deep crypt secretory cells of the ascending colon and the columnar absorptive cell brush border.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗