Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Rectum”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources
PubMed2001

Mesenchymal tumors of muscularis mucosae of colon and rectum are benign leiomyomas that should be separated from gastrointestinal stromal tumors--a clinicopathologic and immunohistochemical study of eighty-eight cases.

Most mesenchymal tumors of the gastrointestinal tract are currently classified as specific gastrointestinal stromal tumors. However, true leiomyomas are more common in the esophagus, and they have been occasionally noted in the colon and rectum, but the small number of reported cases does not allow for clinicopathologic profiling. This study was undertaken to characterize 88 tumors of the muscularis mucosae of the colon and rectum. Seventy tumors were obtained form the files of AFIP and 18 cases from the Department of Pathology of the Haartman Institute of the University of Helsinki. The lesions, except one, were removed by snare polypectomy as incidental lesions at cancer or polyp surveillance; one small tumor was an incidental finding in the rectal resection specimen. The tumors had a significant male predominance in both institutions (overall 2.4:1). They occurred in age range of 38 to 85 years (median 62 years). The lesions were typically small (range 1 to 22 mM, median 4 mM) and located predominantly in the rectum and sigmoid (72%). All tumors were composed of well-differentiated, eosinophilic smooth muscle cells that were seen immediately beneath the mucosa obliterating the muscularis mucosae layer and merging with it. Two tumors had significant atypia ("symplastic leiomyoma"); mitotic activity was seen in one of these tumors, but not in others. The lesional cells were uniformly positive for smooth muscle actin and desmin and negative for CD34, CD117 and S100-protein, based on immunohistochemical studies on 20 to 24 cases with each marker. No gastrointestinal stromal tumors were identified among the tumors of muscularis mucosae, and no CD117-positive cells, except mast cells, were seen in the muscularis mucosae layer. None of the patients had morbidity related to the tumor. Based on follow-up data on 29 patients, leiomyomas of muscularis mucosae are benign. They should be separated from gastrointestinal stromal tumors that have a clinicopathologic spectrum including frequent disease-related mortality. Snare polypectomy is an adequate treatment, but ensuring the complete removal and follow-up are necessary precautions for tumors with any atypia or mitotic activity.

Actins↗
PubMed1998

Discharge patterns of intramural mechanoreceptive afferents during selective distension of the cat's rectum.

The afferent input from the rectum to the central nervous system (CNS) has yet to be thoroughly characterized. The characteristics of mechanoreceptive rectal afferents have been studied in unanaesthetized decerebrate cats. Following lumbo-sacral laminectomy, single-unit activity (occasionally multi-unit activity) was recorded from centrally cut filaments of the sacral dorsal roots (predominantly S2), while a balloon was inflated in the rectum. Starting from their background activities (mean 15.1 imp sec-1, SD 7.6 imp sec-1), afferent discharge rate increased with increasing balloon pressure (mean threshold 6.3 mmHg, SD 3.6 mmHg). The dependence of firing rate on intrarectal pressure began to flatten out at 25 mmHg (mean; SD 10 mmHg). For 22 out of 29 units (76%) complete saturation occurred at 35 mmHg (mean; SD 15 mmHg) with a maximum discharge rate of 31 imp sec-1 (mean; SD 12.6 imp sec-1). In a number of recording sessions, cyclical rectal contractions were observed. In these cases, changes in firing of the units were closely related to changes in intrarectal pressure. Pressure-related afferent activity could be enhanced by parasympathomimetic drugs which augmented rectal contractions. We conclude that sacral dorsal roots contain afferents from low-threshold mechanoreceptors located in the rectal wall, and that these afferents monitor the filling state and contraction level of the rectum.

Animals↗
PubMed2002

Does human papilloma virus have a role in squamous cell carcinoma of the colon and upper rectum?

AIM: To determine if Human Papilloma Virus (HPV) has a role in the aetiology of adenosquamous and squamous cell carcinoma of the colon and upper rectum, and to describe the clinical features seen in our patients with this condition. METHODS: Patients were identified with squamous cell carcinoma (SCC), adenosquamous carcinoma (Ad-SCC), or adenocarcinoma with squamous metaplasia (AA) of the colon and upper rectum over the 10 years from 1/1/1990 to 31/12/1999. Patients were identified from a prospective pathology database. All tumours were at least 5cm above the dentate line. Pathology blocks were stained using the Peroxidase labelled Streptavidin technique using mouse monoclonal antibody NCL-HPV-4C4, which identifies HPV 6, 11, 16 and 18. Age, gender and site matched controls (colorectal adenocarcinomas) were also stained. The clinical presentation and management was reviewed from the case notes. RESULTS: Twenty patients were identified from a pathological database of 2351 colorectal cancers (0.85% of colorectal cancers). 0/20 of the study patients (SCC, Ad-SCC, AA) or adenocarcinoma controls stained positively for HPV 6, 11, 16, 18. The clinical presentation was similar to patients presenting with adenocarcinomas. CONCLUSIONS: The peroxidase labelled streptavidin technique is an immunohistochemical technique with high specificity but lower sensitivity. There was no apparent association between HPV 6, 11, 16, 18 and squamous cell and adenosquamous carcinoma of the colon and rectum using this technique. Clinical features are similar in squamous and adenosquamous colorectal carcinomas to colorectal adenocarcinomas.

Aged↗
PubMed2000

Clarification of the process of separation of the cloaca into rectum and urogenital sinus in the rat embryo.

BACKGROUND/PURPOSE: The normal process of division of the cloaca into a rectum and urogenital tract is still not fully understood. The main controversies relate to how the urorectal septum (URS) divides the cloaca and whether the URS fuses with the cloacal membrane. This study used a 3-dimensional reconstruction technique, combined with histologic correlation, to observe the developmental and septational processes of the cloaca of the normal rat embryo from gestational days 11 to 16. METHODS: Normal rat embryos from gestational days 11 to 16 were sectioned serially both transversely and sagittally and stained with H&E. 3-dimensional reconstructions were performed on embryos younger than day 13.5. The relevant structures were examined in a temporo-spatial sequence. RESULTS: The tailgut started to regress by apoptosis on day 12 in a cranio-caudal direction. The URS, first evident in day-12.5 embryos, extended and fused with the cloacal membrane on day 15 of gestation, completing the separation of the cloaca into rectum and bladder. Regression of the tailgut and ventral protrusion of the urogenital sinus markedly changed the configuration of the cloaca. The cloacal membrane did not break down until after it had fused with the URS. CONCLUSIONS: These findings clarify the relative contributions made by active septation of the cloaca by the URS and configurational changes of the cloaca to produce a rectum and bladder. The URS fuses with the cloacal membrane before the anal and urogenital membranes break down.

Animals↗
PubMed2006

["Fast-Track" for laparoscopic-assisted rectum resection--what can be achieved? First results of a feasibility study].

AIM: "Fast-track" multimodal rehabilitation is increasingly entering the perioperative management strategies in colon surgery aiming at minimized perioperative morbidity and accelerated recovery. So far little is known about the complementary effects of minimally invasive surgery along with "fast-track" rehabilitation in the treatment of rectal cancer. The aim of this pilot study was to investigate the influence of "fast-track" perioperative management on morbidity, recovery and length of hospital stay in laparoscopically-assisted rectum resections and to compare those data to earlier results. METHODS: An interdiciplinary "fast-track" multimodal rehabilitation strategy with avoidance of mechanical bowel cleansing, with a restrictive intravenous intra- and postoperative fluid regimen, forced mobilisation, and early enteral nutrition was introduced into clinical practice and applied in 16 laparoscopically-assisted rectum resections. Data were collected in the course af a prospective analysis. The mean patient age was 62 (42-79) years. RESULTS: Mean time of surgery was 245 (SD 46) min, and the mean intraoperative infusion rate was 11.2 (SD 2.6) ml/kg/BW. On day 2, 14 of the 16 patients tolerated solid food and 12 patients had had bowel movements. All patients returned to their initial body weight by day 4. The median postoperative hospital stay was 7.5 days (6-20), 12 patients were discharged between day 6 and 8. Two patients were readmitted for intestinal atony, one patient developed an anastomotic leakage. CONCLUSIONS: "Fast-track" rehabilitation is feasible in rectum surgery and seems to complement the beneficial effects of minimally invasive surgery without increasing the complication rate.

Adult↗
PubMed1989

Effectiveness of endoscopic treatment of carcinoid tumors of the rectum.

The effectiveness of endoscopic polypectomy in the treatment of carcinoid tumors of the rectum was investigated. Flat tumors of less than 1.5 cm in the largest diameter, of normal or yellow color, consisting histologically of solid nodular nests or trabecular or ribbon-like structures were "early" tumors, in which the tumor cells were confined to the mucosa and submucosa, and did not involve deeper layers. Eight patients with "early" carcinoids were treated by endoscopic polypectomy. Subsequently, two of them were submitted to surgery, while the other six were followed-up endoscopically. Histological examination of the specimens obtained at operation showed no evidence of residual tumor cells at the polypectomy site. Endoscopic follow-up studies also failed to reveal local recurrence in any of the patients during the average observation period of 1.3 years. The wall of the rectum was significantly thicker than that of the sigmoid colon, so that deeper local excision was possible. These findings indicate that even though "early" carcinoid tumors of the rectum showed submucosal invasion, they were completely cured by local endoscopic excision.

Aged↗
PubMed2001

Motor and sensory function of the rectum in different subtypes of constipation.

BACKGROUND: It is not known whether evaluation of motor and sensory function of the rectum using a barostat may help to distinguish subtypes of constipation. METHODS: Motor and sensory function of the rectum have been evaluated using a barostat in 14 patients with slow transit constipation (STC), 12 patients with constipation-predominant irritable bowel syndrome (IBS) and 18 healthy controls. First minimal distending pressure was determined, after which spontaneous adaptive relaxation of the rectum was monitored. Then a step-wise isobaric distension procedure was performed, during which symptom perception was determined. The distension was followed by a 90-min barostat procedure: for 30 min in the basal state followed by ingestion of a semi-liquid meal (postprandial state). RESULTS: Minimal distending pressure was not different between both patient groups and controls, neither was compliance different between constipated patients and controls. The degree of spontaneous adaptive relaxation was in the same range in all groups. During distensions with high pressures, the perception of urge was significantly reduced in STC patients compared to IBS and controls, while the perception of pain was significantly increased in IBS versus STC and controls. Postprandially, a small decrease of rectal volume was only observed in the control group, but not in the patients. CONCLUSIONS: Rectal motor characteristics are not different between patients with constipation-predominant IBS, patients with STC and healthy controls while during isobaric distensions, sensations of urge were reduced in STC and sensations of pain were increased in IBS. Rectal visceroperception testing may help distinguish groups of patients with different subtypes of constipation.

Adult↗
PubMed2001

Sensitivity and distensibility of the rectum and sigmoid colon in patients with irritable bowel syndrome.

BACKGROUND: Hyperalgesia to visceral stimuli is a biological marker of the irritable bowel syndrome (IBS). Abnormal pain processing is probably of most importance, but biomechanical abnormalities of the gut wall may also contribute to the findings. In the current study, we investigated the sensation of the gut to electrical stimuli as well as the distensibility of the rectum and sigmoid colon in IBS patients and a control group. METHODS: Nine patients with IBS and 11 controls entered the study. The pain threshold to electrical stimuli at the rectosigmoid junction was determined with bipolar electrodes integrated on the biopsy forceps for the endoscope. Subsequently, controlled distensions of the sigmoid colon and rectum were performed with a balloon integrated on a probe for impedance planimetry, providing the possibility to measure the cross-sectional area (CSA), wall tension and strain to different pressures together with the sensation ratings. RESULTS: The pain detection thresholds to electrical stimuli at the rectosigmoid junction were 12.5 (range 7-39) mA in controls and 7.5 (range 0.75-12) mA in IBS patients (P = 0.03). The calculated pressures at the pain detection threshold in the sigmoid colon were lower in the IBS patients (31.5 (range 5-58) versus 5 cm (range 5-25) water; P = 0.03), otherwise no differences were seen in sensation rating to the different distension pressures. The CSA was slightly higher in controls to the different pressures, whereas no differences between the groups were seen in strain and tension of the rectum and sigmoid colon. CONCLUSION: The visceral hypersensitivity in IBS seems to be related to alterations in the nervous system rather than biomechanical parameters such as the tension and strain of the gut wall. Treatment of pain in IBS should therefore be based on drugs with documented action on the nociceptive pathways in the central nervous system.

Adult↗
PubMed2004

Evaluation of a new method for calculation of cumulative doses in the rectum wall using repeat CT scans.

The rectum wall is an important organ at risk during irradiation of the prostate, the bladder and other organs in the pelvis. It is therefore of great interest to be able reliably to predict normal tissue complication probabilities (NTCPs) for this organ. Because the rectum wall is a hollow organ capable of large deformations between fractions, dose estimates from a single CT are unreliable, and thereby also NTCP estimates. In this study two methods for calculations of cumulative dose distributions from repetitive CT scans are compared. The first is a method presented in this article that uses tracking of volume elements for a direct summation of the doses delivered in the treatment fractions. The other, presented earlier (1), is based on information from dose-volume histograms. The comparisons were made in terms of equivalent uniform doses (EUDs) and NTCPs. The methods were also compared with mean values of EUD and NTCP values from individual CT scans. The study showed that with the relatively symmetric beam arrangements normally used for treatment of prostate and bladder cancer, it is not necessary to use the more laborious method of element tracking. However, an introduction of artificial lateral rectum movements revealed that element tracking is necessary in less symmetric situations.

Carcinoma, Transitional Cell↗
PubMed2006

Halftime for repair of sublethal damage in normal bladder and rectum: an analysis of clinical data from cervix brachytherapy.

The halftime for repair of sub-lethal damage is an important radiobiological parameter in analysing radiation responses and in designing new treatments involving different dose rates. This work is to resolve an inconsistency existing in the repair halftime for the bladder and rectum, two of the most dose limiting critical structures for pelvic irradiation. Both long (1.5-2 h) and short (0.3-1 h) repair halftimes have been reported previously. In this work, by reconciling clinical data from cervical brachytherapy of different dose rates and by introducing a sparing factor to consider the dose sparing occurring for critical structures, we have estimated that the most likely value of the repair halftime for bladder and rectum is short, 0.2-0.4 h if assuming alpha/beta = 2-4 Gy. The present analysis does not support the long repair halftimes reported previously for the bladder and rectum and for other normal structures.

Brachytherapy↗
PubMed1984

Sensitivity of the sigmoid colon and rectum in children treated for chronic constipation.

Sensations in the sigmoid and rectum and the response of the anal canal to balloon distension were measured with a latex balloon and pressure transducer in 15 chronically constipated and 15 healthy control children. The constipated children received milk of magnesia and bowel training. Thirteen constipated children were restudied 7-12 months later and 11 were restudied 3 years later. Although thresholds of transient sensation and of the rectosphincteric reflex were not different in constipated and control children, the threshold of fullness, the critical volume, and the volume for constant relaxation were significantly higher in constipated than in control children (p less than 0.05), and remained higher 1 year and 3 years later, even in the children who recovered. The initial data support the concept of a sigmoid and rectum so enlarged that a normal fecal bolus may not cause a sensation of fullness or a sensory stimulus for defecation. Despite improvement in clinical manifestations and normal rectal size, the abnormalities in sensitivity of the sigmoid and rectum persisted in five of eight recovered children. This may explain why these children are so vulnerable to recurrence of constipation and fecal soiling.

Anal Canal↗
PubMed1975

Iatrogenic lesions of the colon and rectum.

Our ability to document a number of examples of iatrogenic lesions of the colon and rectum in three general hospitals confirms the multiplicity of these lesions as presented in the literature. It appears that the careful surgeon and his associates would well heed the old admonition known as Murphy's law, that "Anything that can go wrong will go wrong." In the daily practice of the general surgeon and proctologist, it is apparent that gentleness in approaching any anal-rectal examination for either diagnostic or therapeutic purposes is mandatory. The insertion of any foreign object, be it an examining finger, a thermometer, enema tip, or proctoscope, may subject the patient to an inadvertent injury of significant proportion. The dangers inherent in the evaluation and treatment of patients with recognized disease processes is significantly greater than that associated with routine and screening examinations. Morbidity and mortality have been shown to be associated with the barium enema as well as with the barium enema as well as with some of the newer radiologic procedures such as mesenteric angiography. The use of tap water for enemas has produced morbidity both from thermal injuries and from electrolyte depletion. Antibiotics and chemotherapeutic drugs frequently result in colon and rectal disease, and therapeutic procedures directed at organs adjacent to the colon and rectum have resulted in a number of iatrogenic lesions. This reviews confirms reports of others that iatrogenic lesions of the colon and rectum are not solely due to the physician's inexperience, as significant numbers of these lesions were the result of the diagnostic or therapeutic efforts of men of considerable experience and skill. Advanced age of the patient and diseases leading to changes in the character of the bowel wall frequently were factors in the production of these lesions. A poorly prepared bowel has led to increased morbidity and mortality associated with iatrogenic perforations. The early recognition of these lesions and prompt medical and surgical management diminishes both the morbidity and mortality associated with such injuries.

Adult↗
PubMed2006

Pain and mechanical properties of the rectum in patients with active ulcerative colitis.

BACKGROUND: The pain, urgency, and incontinence in ulcerative colitis may be related to changes in viscoelastic properties of the gut wall or to alterations of the sensory pathways. In the present study, we used an advanced rectal probe to study the mechanosensory and smooth muscle properties in patients with active disease. METHODS: Nine patients with ulcerative colitis (mean age 39.5 years) with exacerbation limited to the rectum and sigmoid colon and 17 age-matched healthy subjects were included. The rectum was distended before and after pharmacological relaxation of the smooth muscle until moderate pain was reported, and the cross-sectional area, volume, pressure, tension, and strain were computed. To investigate central integration of a tonic stimulus, the bag was finally distended to the pain threshold; then, the cross-sectional area was held constant for 2 min. RESULTS: The patients were hypersensitive to mechanical stimuli as assessed by the cross-sectional area (F = 21.7; P < 0.001). There were no differences in compliance or stiffness between the 2 groups, but the hypersensitivity was abolished after muscle relaxation. Together with the muscle analysis, this finding demonstrated that the smooth muscles were tonically contracted in the inflamed rectum, resulting in a decreased rectal circumference. The tonic distensions did not evoke central integration of the pain response, indicating that hyperalgesia is more likely related to peripheral factors. CONCLUSIONS: Patients with active ulcerative colitis have hypersensitivity and increased tone of the smooth muscles, which may explain the symptoms. Drugs that affect smooth muscle contraction may be helpful in difficult cases.

Adult↗
PubMed2005

Escherichia coli O157 : H7 forms attaching and effacing lesions at the terminal rectum of cattle and colonization requires the LEE4 operon.

Enterohaemorrhagic Escherichia coli O157 : H7 is a human pathogen that causes no apparent disease in cattle, its primary reservoir host. Recent research has demonstrated that E. coli O157 : H7 predominately colonizes the distal few centimetres of the bovine rectum, and in this study, the LEE4 operon encoding a type III secretion system translocon and associated proteins was shown to be essential for colonization. A deletion mutant of LEE4 failed to colonize cattle, in contrast to a co-inoculated strain containing a chromosomal complement of the operon, therefore fulfilling 'molecular' Koch's postulates for this virulence determinant. In addition, attaching and effacing (A/E) lesions were detectable in E. coli O157 : H7 microcolonies from the terminal rectum of both naturally and experimentally colonized cattle when examined by transmission electron microscopy. This study proves that type III secretion is required for colonization of cattle by E. coli O157 : H7, and that A/E lesion formation occurs at the bovine terminal rectum within E. coli O157 : H7 microcolonies. The research confirms the value of using type III secreted proteins as vaccine candidates in cattle.

Animals↗
PubMed2006

The effect of a probiotic drink with Lactobacillus plantarum 299v on the bacterial composition in faeces and mucosal biopsies of rectum and ascending colon.

BACKGROUND: Studies on probiotics mainly base their results on faecal samples, which may not represent the situation in the mucosa of distal and proximal colon. AIM: In a placebo-controlled study, to assess the effect of Lactobacillus plantarum 299v on the bacterial composition of faecal vs. mucosal samples. METHODS: Twenty-nine patients undergoing colonoscopic examination for polyps consumed a twice-daily drink with or without L. plantarum 299v (10(11) CFU/day) for 2 weeks. Faecal samples were collected before and after consumption. During colonoscopy, biopsies were collected from the ascending colon and rectum. The faecal and mucosal bacterial concentrations and prevalence were determined. RESULTS: L. plantarum 299v significantly increased the concentration of faecal lactic acid bacteria, lactobacilli and clostridia, and was identified in two rectal biopsies but not in the ascending colon biopsies of probiotic-treated subjects. Concentrations and prevalence in ascending colon and rectum biopsies were comparable, but were significantly lower compared with faecal samples. CONCLUSIONS: After probiotic consumption, a significant increase in the faecal concentration of lactobacilli was found but concentrations were low in biopsies. The bacterial composition in biopsies of the ascending colon and rectum did not differ based on culture techniques. To further elucidate the modes of action of probiotics, it might be necessary to study differences in colonization with molecular techniques.

Beverages↗
PubMed2006

Electrical activity in the rectum of anaesthetized dogs.

There is limited data available on the electrical activity of the rectum. An in vivo canine model was developed to record 240 extracellular electrograms simultaneously from the serosal surface of the rectum thereby enabling an off-line reconstruction of the behaviour of the electrical signals. Serosal rectal electrical activity is characterized by brief bursts of action potentials (=spikes) with a frequency of 22 cycles min(-1). High-resolution mapping of these signals revealed predominant propagation of these spikes in the longitudinal direction, originating from any site and conducted for a limited time and length before stopping spontaneously, thereby describing a patch of activity. The dimension of the patches in the longitudinal direction was significantly longer than the transversal width (13.6 vs 2.4 mm; P < 0.001). Spike propagation could occur in the aboral (46% of cases), in the oral (34%) or in both directions (20%). A bolus of betanechol (i.v., 0.5 mg kg(-1)) increased the frequency of the spikes without affecting size, shape or orientation of the patches. As in other parts of the gastrointestinal system, individual spike propagation in the rectum is limited to small areas or patches. The contractile activity of the organ could possibly reflect this underlying pattern of electrical behaviour.

Action Potentials↗
PubMed1988

Protruded variants in solitary ulcer syndrome of the rectum.

A review of 21 patients with protruded lesions in solitary ulcer syndrome of the rectum confirmed by resection is presented. Symptoms were usually the passage of blood and mucus per rectum, alteration of bowel habit, anorectal pain and rectal prolapse. Solitary or multiple polypoid lesions were found within 15 cm of the anal margin and were usually sited anteriorly. Fifteen of the patients were men and 8 were women with a mean age of 37.1 years. The diagnosis was made on the basis of histopathology; 1) fibrous obliteration of muscle fibers, 2) reactive hyperplasia of the mucous membrane with villous configuration or mild pseudoinvasion. These changes have been observed in complete rectal prolapse, colonic intussusception, and localized colitis cystica profunda, suggesting a common pathogenesis. The histological findings were almost the same as in the ulcerative lesions of this syndrome except for remarkable regenerative hyperplastic changes such as a relatively high incidence of mucous cell proliferation, dilatation of glands and serrate change in the cases showing protrusion. In the pathogenesis, the occult mucosal prolapse in association with excessive straining may be of particular importance, so that the lesions might be termed mucosal prolapse syndrome of the rectum.

Adolescent↗
PubMed1970

Adrenoceptors of the chick rectum.

1. The aim of the investigation was to determine whether the adrenoceptors of the chick rectum preparation complied with Ahlquist's classification; phentolamine (0.1 mug/ml) and propranolol (0.05 mug/ml) were used as specific antagonists of alpha- and beta-adrenoceptors, respectively.2. Propranolol antagonized phenylephrine, isoprenaline and noradrenaline in the chick rectum preparation, although according to Ahlquist's classification phenylephrine stimulates alpha-adrenoceptors selectively.3. In the presence of propranolol, phenylephrine and noradrenaline produced small residual relaxations of the chick rectum preparation which were blocked by phentolamine. In the absence of propranolol, however, phentolamine did not antagonize relaxations to phenylephrine, isoprenaline or noradrenaline.4. The adrenoceptors of the guinea-pig colon preparation compiled with Ahlquist's classification in that they were like those generally present in intestine.

Adrenergic alpha-Agonists↗