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Effects of the adenosine A1-receptor antagonist on defecation, small intestinal propulsion and gastric emptying in rats.

We examined the effects of 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) and (R)-7,8-dihydro-8-ethyl-2-(3-noradamantyl)-4-propyl-1H-imidazo[2,1 -i]purin- 5(4H)-one (KF20274), selective adenosine A1-receptor antagonists, on the gastrointestinal propulsion in rats, as compared with those of the laxative bisacodyl. DPCPX and KF20274 (p.o.) dose-dependently increased the fecal pellet output, whereas these drugs at the dose that increased defecation did not affect small intestinal propulsion or gastric emptying. Bisacodyl increased defecation and slowed gastric emptying without any influence on small intestinal propulsion. Bisacodyl, but not DPCPX or KF20274, induced diarrhea at the dose inducing defecation. The present results suggest that the adenosine A1-receptor antagonist selectively enhances the lower gastrointestinal propulsion, resulting in defecation without diarrhea.

Adamantane↗

Effects of brewer's yeast cell wall on constipation and defecation in experimentally constipated rats.

Brewer's yeast cell wall (BYC) was tested on constipated male Sprague-Dawley rats that had been induced by loperamide (2 mg/kg of body weight). The preventive effect of BYC on constipation was examined and compared with that of a non-fiber diet (NF) as the control. The dose-response of BYC and the effect on defecation by constipated experimental rats were also compared with the characteristics of cellulose diet (CE) group which served as a control. Defecation was observed to be greater by the rats fed with BYC than by those fed with NF or CE. The fecal water content and level of volatile fatty acids (VFA) in the cecal contents were likewise higher in the rats fed with BYC. These results indicate that the administration of BYC was effective for improving defecation and other parameters related to defecation. These favorable effects of BYC supplemented to the diet are attributed to the fermentation ability, water holding capacity and swelling force in the large intestine.

Antidiarrheals↗

The defecation pattern and diet in patients with an ileum reservoir and anal anastomosis with a long efferent leg.

The dietary habits and defecation patterns of 12 patients were examined 8-34 months after total colectomy with mucosal proctectomy and the construction of an ileal reservoir attached to an anal anastomosis. The reservoir was provided with a long efferent leg (12 cm) through the anal canal. The patients were divided into two groups in accordance with the frequency of defecation--one with fewer than six defecations per 24 h and another with more than six defecations per 24 h. The fecal output, however, was not significantly different in the two groups. The fecal content of sodium and potassium was the same as in feces from conventional ileostomies. The dietary intake was insufficient in energy content, vitamins, minerals, and trace elements. Dietary supplement was recommended.

Adult↗

Defecation mechanisms in conscious dogs after total colectomy with ileorectal anastomosis.

To clarify defection mechanisms in those with total colectomy, we performed comparative studies of intestinal motility in two groups of straight and J-pouch ileorectal anastomosis. In the straight group, 98 percent of the interdigestive migrating contractions (IMC) reached the anastomosis and 48 percent of the defecations were affected by the contractions. In the J-pouch group, 16 percent of the contractions reached the anastomosis and only 8 percent of the defecations were related to the contractions. We conclude that transmission of IMC to the rectum is related to the frequency of defecation after total colectomy and that the disappearance of IMC in the J-pouch anastomosis reduced the frequency of defecations in those instances.

Animals↗

Recto-colic reflex: role in the defecation mechanism.

As urge is felt and defecation starts, it is postulated that the colon continuously feeds the rectum with stools until the colon is empty. The relationship of rectal distension at defecation to colonic activity is not yet fully explored. The current communication studies this relationship in 11 patients (mean age 48.4+/-18.8 years, 6 men and 5 women) with transverse colostomy performed after transverse colectomy for cancer of the transverse colon. The rectum was distended by a condom-ended catheter in increments of 10 ml of H20, and the pressures in the right and left colon were measured by balloon catheters introduced through the colostomy. The test was repeated after anesthetizing the rectum or colon, respectively. Upon rectal distension up to sensation of urge, there was no colonic pressure response. At urge (mean distension volume of 160+/-36.7 ml), the left colonic pressure showed a significant rise (p<0.001), while the right colon revealed no response (p>0.05). Rectal distension during rectal or colonic anesthetization effected no colonic pressure response (p>0.05). The left colonic contraction upon rectal distension, being reproducible and absent with the anesthetized rectum or colon, postulates a reflex relationship which we call "recto-colic reflex". This reflex acts at defecation to feed the rectum successively with fecal material until the colon is emptied. Reflex derangement may play a role in defecation disorders.

Adult↗

How useful are manometric tests of anorectal function in the management of defecation disorders?

OBJECTIVES: The clinical usefulness of assessing anorectal physiology has not been systematically examined. Our aims were to evaluate whether manometric tests of anorectal function influence the management and outcome of patients with defecation disorders, and to identify the patients who may most benefit from this assessment. METHODS: Using a standard protocol of anorectal manometry rectal sensation, saline continence, simulated defecation, and pudendal nerve terminal latency tests, we studied 143 consecutive patients (m/f = 27/116) and followed their progress over 18 months. RESULTS: Tests of anorectal function in 126 (88%) patients revealed new information that led to a change in the management of 108 (76%) patients. Among 69 patients referred with constipation, 33 (48%) had obstructive defecation, and 40 (58%) had impaired rectal sensation; 30 (43%) improved after biofeedback therapy. Among 56 patients referred with fecal incontinence, 55 (98%) had manometric abnormalities: 30 (53%) had a low squeeze sphincter pressure, 20 (36%) had impaired rectal sensation, and 28 (50%) had pudendal neuropathy. Thiry-four (60%) patients were referred for biofeedback therapy and 11 (20%) for surgery. Of these 15 completed biofeedback therapy with improvement, and six had successful surgery. Seven of 10 (70%) patients referred for preoperative evaluation had abnormalities that contraindicated surgery. CONCLUSIONS: Manometric tests of anorectal function provide not only an objective diagnosis but, also, a better understanding of the underlying pathophysiology. In addition, it provides new information that could influence the management and outcome of patients with disorders of defecation.

Adolescent↗

The current understanding of continence and defecation.

Problems of continence and defecation are encountered in all facets of medical practice. Yet, the anorectum is cloaked by misunderstanding. Recent research has shed new light on this subject and newer concepts based on systematic investigations have paved the way to a rational approach. Motor function of the anorectum can now be delineated by manometry, electromyography and nerve stimulation. More complex functions like the coordination for continence and defecation are measured using other studies including defecating proctography, scintigraphic balloon topography, scintigraphic evacuation and colonic transit. The amalgamation of data from these studies have led to a logical sequence for the maintenance of normal continence and defecation that is developed in this manuscript based on our current understanding of anorectal motility and physiology. This allows patients who are resistant to straightforward diagnosis to be selected for specialised tests resulting in categorisation and a rational management strategy for their problems.

Anal Canal↗

[A case of giant vesical diverticula causing defecation disturbance].

Cases of giant vesical diverticula that cause defecation disturbance are very rare. A 67-year-old man with such a condition was admitted to our hospital complaining of pollakiuria , nycturia , retardation, two-phase urination and defecation disturbance which began about 7 years earlier. A goose-egg-sized tumor touched above the hen-egg-sized prostate and the tumor disappeared after urination. X-ray examinations revealed that defecation disturbance was caused when the sigmoid colon was oppressed by the giant diverticulum. After diverticulectomy and prostatectomy the vesical symptoms and defecation disturbance completely subsided.

Aged↗

The technical aspects of biofeedback therapy for defecation disorders.

Neuromuscular conditioning using biofeedback techniques is a useful method of treatment for patients with refractory defecation disorders such as fecal incontinence or constipation with obstructive defecation. This article provides current perspectives regarding the principles and techniques of performing biofeedback therapy. In patients with incontinence, the goals are to improve the strength of the anal sphincter, improve sensory perception, and improve coordination between the rectum and anal sphincter. In patients with obstructive defecation, the goals are to relax the anal sphincter, improve rectoanal coordination, and improve sensory perception. Neuromuscular conditioning is an instrument-based learning technique. Over the years, several devices and methods have become available for performing this training, but no single method is either superior or universally popular. The three modalities that are commonly used for neuromuscular conditioning are visual, verbal, and audio feedback. Ideally, the training program should be customized for each patient based on the underlying dysfunction(s). After biofeedback therapy, symptomatic improvement has been reported in 70 to 80% of patients with either incontinence or obstructive defecation. Recent studies also demonstrated objective improvement in anorectal function. In the future, it is likely that simpler and user-friendly, solid-state computerized systems may facilitate a wider use of this treatment.

Biofeedback, Psychology↗

Autonomic dysfunction in end-stage liver disease manifested as defecation syncope: impact of orthotopic liver transplantation.

Patients with end-stage liver disease (ESLD) may be at increased risk for syncopal episodes based on their circulatory physiological state. Although a definitive cause for this is not known, several mechanisms have been proposed. In patients with ESLD, defecation syncope may result from a failure of short-term neurocirculatory adaptation to the Valsalva maneuver in the face of a hyperdynamic circulatory state and a decreased effective intravascular volume. We describe 2 patients with ESLD who had repeated episodes of defecation syncope before orthotopic liver transplantation (OLT). The most effective treatment of these syncopal episodes appears to be fluid administration and the use of a pressor agent, such as dopamine, to help maintain both an effective heart rate and intravascular volume. Correction of this altered circulatory physiological state through OLT prevented further syncopal episodes in both patients. A search of the literature failed to show previous reports associating ESLD and defecation syncope. Possible mechanisms favoring this association are reviewed.

Adult↗

Rectopexy is an ineffective treatment for obstructed defecation.

The symptoms of obstructed defecation have been attributed to rectal intussusception, and thus rectopexy has been advocated in the surgical management. In this study, patients with obstructed defecation underwent manometry and proctography before and after rectopexy. Seventeen patients (16 females and one male, mean age 51.6 years) were studied. Eleven underwent anterior and posterior fixation of the rectum and six had posterior fixation only. Preoperatively five patients demonstrated rectoanal intussusceptions. Fifteen had significant pelvic descent. No significant change in maximum resting pressure, maximum voluntary contraction, pelvic descent, or anorectal angle was seen postoperatively. In the initial follow-up, many patients had significant amelioration of symptoms. However, on longer follow-up (mean 30.8 months) only two had long-term improvement. The remainder had a poor clinical result in spite of complete resolution of rectal intussusception. Many reported a worsening of symptoms as reflected by an increase in tenesmus and stool frequency. In the two cases with a satisfactory result, both could empty the rectum completely and demonstrated rectoanal intussusception on preoperative evacuation proctography. In those with poor results, four had complete emptying and three had rectoanal intussusception. In conclusion rectopexy is an ineffective treatment for obstructive defecation in most patients.

Adult↗

Evaluation of ability to defecate using saline evacuation from the rectum.

PURPOSE: The purpose of this study is to establish a simple technique to evaluate anorectal motility and the dynamics of defecation. METHODS: Pressure fluctuations in the rectum and anal canal during 500 ml of saline infusion in the rectum and then a saline evacuation curve were recorded using manometer and uroflowmeter. RESULTS: This study consisted of 37 patients with a mean age of 49.6 years. All patients without problems with defecation showed periodic relaxation of the anal canal, which was synchronized with rectal contractions during saline infusion. The saline evacuation curves of these patients were characterized by short evacuation time and high-peak flow. Of the 13 patients with constipation, 9 showed no rectoanal synchronization and had segmental evacuation curves. The patients with incontinence tended to have poor ability for holding saline in the rectum, resulting in low-peaked evacuation curves. CONCLUSIONS: This simple and noninvasive technique for recording anorectal pressure fluctuations and dynamics of saline evacuation from the rectum enables quantitative and qualitative evaluation of the ability to defecate.

Anal Canal↗

A combined electromyographic and cineradiologic investigation in patients with defecation disorders.

Records from 20 patients on whom defecography and electromyography were performed simultaneously because of defecation disorders were analyzed. According to the electromyographic investigation, the patients could be divided into three main groups: 1) normal sphincter reaction; 2) paradoxical sphincter reaction; and 3) combined reaction. Group A was characterized by a marked reduction of muscular activity during emptying and a pronounced closing reflex after emptying. This was followed by return of normal tonic activity. Patients in group B had no relaxation of the sphincters during emptying but a pronounced increased activity in the external sphincter and the puborectalis muscle. They also had severe emptying difficulties at defecography. No closing reflex was seen. In group C the electrical activity in the sphincters increased during moderate straining and when emptying was complete a clear closing reflex was seen. In this study, a dynamic visualization of the defecation together with a registration of electromyographic activity in the striated anal sphincters was performed. It was shown that patients with paradoxical sphincter reaction were lacking a closing reflex after emptying was complete. This has not been reported previously and is important evidence for the paradoxical defecation pattern. It was also shown that the patients with rectoceles had paradoxical sphincter reaction.

Adult↗

Diagnosis of disturbances of continence and defecation.

Defecography was performed in 60 patients with disorders of continence or defecation in whom previous investigative procedures had not revealed any abnormality that could explain the disorder. A correct diagnosis was made in 47 patients (78%). Defecography appears to be a suitable procedure to detect functional disturbances of defecation. Since anterior rectal wall abnormalities such as colitis cystica profunda and solitary rectal ulcer were seen in eight patients, it is suggested that these abnormalities are a result of functional disorders of defecation. Furthermore, the function of the pelvic floor musculature can be assessed by defecography in order to determine the cause of fecal incontinence.

Adolescent↗

A concept of the anatomy of the anal sphincter mechanism and the physiology of defecation.

A review of the new concepts of the anatomy of the anal sphincter mechanism and the physiology of defecation is presented. The external sphincter is a triple-loop system; each loop can function as a separate sphincter through voluntary inhibition action and mechanical compression. Stress defecation resulting from internal sphincter damage is described. A new technique for repair of rectal incontinence is presented, which depends on inducing continence not only by mechanical compression, but also by voluntary inhibition. The mechanism of defecation and rectal continence is described and four types of incontinence presented. Also, the mechanism of both the levator dysfunction syndrome and prolapse is demonstrated and a technique of repair is presented. The study defines two types of rectal anomalies; suprahiatal and infrahiatal. The role of the embryonic anorectal sinus, anorectal band, and epithelial debris in the genesis of perirectal suppuration, chronic anal fissure, pruritus ani, and hemorrhoids is described. The communicating veins, identified between the hemorrhoidal and vesical plexuses, offer an explanation for the vague pathologic aspects of recurrent bacteriuria, urethral discharge, cervicitis, and vaginitis, and provide a proper line for their treatment. They also serve to perform a new radiographic technique--anal cystography--and to administer drugs, including chemotherapeutics, in the treatment of pelvic malignancies.

Anal Canal↗

Possible physiological role of endogenous adenosine in defecation in rats.

Evacuated feces after intraperitoneal administration of selective adenosine receptor antagonists were evaluated in rats. The selective adenosine A1 receptor antagonists, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) (100-300 micrograms/kg i.p.) and (R)-7,8-dihydro-8-ethyl-2-(3-noradamantyl)-4-propyl-1H-imidazo[2,1 -i]purin- 5(4H)-one (KF20274) (30-300 micrograms/kg i.p.), significantly increased defecation, whereas the selective adenosine A2 receptor antagonist 4-amino-8-chloro-1-phenyl[1,2,4]triazolo[4,3-a]quinoxaline (CP-66,713) failed to cause a significant increase at up to 10 mg/kg i.p. The defecation caused by DPCPX (100 micrograms/kg) was markedly alleviated by (2S)-N6-(2-endo-norbornyl)adenosine ((S)-ENBA) (30-300 micrograms/kg s.c.), a selective adenosine A1 receptor agonist, but not influenced by 2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosin e (CGS 21680) (30-1000 micrograms/kg s.c.), a selective adenosine A2 receptor agonist. These results suggest that endogenous adenosine plays a physiological role in sustained inhibition of defecation via adenosine A1 receptors.

Adenosine↗

Failure to induce defecation in rats exposed to fixed-time schedules of liquid food delivery.

Previous studies have found that defecation increases in rats exposed to fixed-time schedules of dry food delivery. The purpose of the present study was to examine whether increases in defecation could be induced in rats exposed to fixed-time schedules of liquid food delivery. Eight rats were exposed to fixed-time 30-, 60-, and 120-s schedules of liquid food delivery. None of the subjects excreted significantly more fecal boli under the fixed-time schedules than during massed-food control sessions in which an equivalent amount of food was presented at the beginning of the sessions. Thus, the present findings identify a previously unknown constraint on schedule-induced defecation in rats.

Animals↗

Effects of MIF-I and melatonin on novelty-induced defecation and associated plasma 11-OHCS and brain catecholamines.

In two experiments the effects were investigated of MSH-inhibiting factor-I (MIF-I) and of Melatonin on step-down latencies, defection, plasma 11-OHCS levels, whole brain DA and whole brain NE concentrations on Days 1, 3 and 5 of novelty exposure. Treatment with MIF-I led to a significant habituation of novelty-induced defecation over 5 days, whereas plasma 11-OHCS level was reduced only on Day 1. The concentrations of whole brain DA and whole brain NE also showed a significant increase over days of MIF-I and novelty treatment. Melatonin treatment, on the other hand, significantly inhibited novelty-induced defecation and reduced plasma 11-OHCS level on Day 5 of novelty exposure. Melatonin treatment led to a significant increase of whole brain DA in animals exposed to novelty for 5 days. Neither MIF-I nor Melatonin was found to significantly affect the step-down activity of treated animals. The overall results suggested a possible relationship between novelty-induced defecation and brain DA levels of MIF-I and Melatonin treated animals.

11-Hydroxycorticosteroids↗