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The effect of feeding on defecation behaviour in pigs.

The effect of eating on defecation behaviour was investigated in four 20-30 kg pigs. Rectal distention stimulation was performed pre- and postprandially at 10 cm from the anus with a 5 cm latex balloon. Volume was increased in steps of 10 ml up to 200 ml of air or until balloon defecation. Dependent measures were volume, rectal pressure, determined with a solid state pressure transducer inside the balloon probe, rectal compliance, and an index of distention induced contractile activity. The volume and pressure required to elicit defecation was significantly lower after feeding (p less than 0.01). Distention induced contractile activity was significantly increased near defecation threshold, but pre- and postprandial conditions were not different. There was no difference in rectal compliance pre- and postprandially. These results suggest that eating lowers defecation threshold in terms of distention volume and rectal pressure, and that these changes are not dependent on altered rectal compliance or changes in distention induced motor activity.

Animals↗

Effects of biofeedback therapy on anorectal function in obstructive defecation.

Biofeedback therapy improves symptoms in patients with constipation and obstructive defecation. Whether it also improves anorectal function is unclear. Our purpose was to investigate prospectively the effects of biofeedback therapy on subjective and objective parameters of anorectal function in 25 consecutive patients with obstructive defecation. Biofeedback therapy consisted of pelvic floor relaxation exercises (phase I) and neuromuscular conditioning of rectal sensation and rectoanal coordination, with a solid state manometry system and simulated defecation maneuvers (phase II). The number of sessions was customized for each patient. Clinical improvement was assessed from the changes in anorectal manometry, balloon (50 cc) expulsion test, and the symptom and stool diaries. The number of therapy sessions varied [mean (range) = 6 (2-10)]. After therapy, when straining as if to defecate, the percentage anal relaxation, intrarectal pressure, and defecation index increased (P < 0.001). The balloon expulsion time, laxative consumption, and straining effort decreased (P < 0.001). Before therapy, 16/25 (64%) patients had impaired rectal sensation, and after therapy this improved (P < 0.001). After therapy, 15/25 (60%) patients reported > or = 75% satisfaction with bowel habit and 8/25 (32%) reported > or = 50% satisfaction (P < 0.001); 15/16 (94%) patients discontinued digital disimpaction. Biofeedback therapy not only improves subjective but also objective parameters of anorectal function in at least 76% of patients by rectifying the underlying pathophysiologic disturbance(s). Sensory conditioning and customizing the number of sessions may offer additional benefits.

Adult↗

Voluntary suppression of defecation delays gastric emptying.

We wished to test the hypothesis that colonic loading with fecal material leads to delayed gastric emptying. Twelve healthy male volunteers were studied. Each of these subjects went through two randomized study periods of four days. In one of these, the subjects defecated upon urge, in the other period defecation was voluntarily suppressed. Gastric emptying of a semisolid meal (mashed potatoes) was measured with the noninvasive applied potential tomography technique. On day 3 no significant changes in gastric emptying were found, but on day 4 the emptying rate had decreased from 85.8 +/- 11.0%/hr (mean +/- SEM) to 70.3 +/- 10.9%/hr (P < 0.05) and the T50 had increased from 38.5 +/- 3.4 min to 46.2 +/- 4.0 min (P < 0.025). The duration of the lag phase (4.1 +/- 1.5 min) was not significantly altered by suppression of defecation. Our conclusion is that voluntary suppression of defecation delays gastric emptying in normal subjects. This "cologastric brake" may be involved in the pathogenesis of upper abdominal symptoms in constipated patients.

Adult↗

Simultaneous defecography and peritoneography in defecation disorders.

UNLABELLED: A number of physiologic and radiologic investigations are used in investigating defecation disorders. Defecography is one important part of these investigations. However, a correct diagnosis of an enterocele is sometimes difficult despite use of contrast media in the rectum, vagina, and small bowel. PURPOSE: This study was undertaken to ascertain if it was technically possible to perform simultaneous defecography and peritoneography in an effort to improve the diagnostic possibilities in patients with defecation disorders. METHODS: Twelve patients with defecation disorders and an unexplained widening of the rectovaginal space at defecography were investigated. Contrast medium was introduced intraperitoneally, after which conventional defecography was performed. RESULTS: All investigations were carried out without complications and demonstrated the peritoneal outline in all patients. Simultaneous defecography and peritoneography differentiated between an enterocele and a pathologically deep pouch of Douglas--a peritoneocele. Three types of peritoneocele were visualized: vaginal peritoneocele, septal peritoneocele, and rectal peritoneocele with or without enterocele. Combinations of the three types were also found. Eight of the 12 patients had rectal intussusception or rectal prolapse. All of these eight patients had a rectal peritoneocele. CONCLUSIONS: Simultaneous defecography and peritoneography can be performed without technical difficulties or complications. Peritoneal outlines and pouches can, therefore, be studied directly during the act of defecation. An unexplained widening of the rectovaginal space at defecography can be clarified as a peritoneocele, with or without an enterocele. Peritoneocele can be of three different types: rectal, septal, or vaginal.

Aged↗

Dynamic anal manometry in the assessment of patients with obstructed defecation.

Patients with obstructed defecation show no consistent abnormalities when assessed by standard anorectal physiologic methods. With a recently developed technique for dynamic anal manometry, we studied 13 female patients with obstructed defecation and 20 healthy volunteers. Seven parameters of anal function were measured. There were no differences between the median values for the two groups. Seven patients (54 percent; 95 percent confidence limits, 25-81 percent) had anal compliance below the normal range, either during opening or closing of the sphincter at rest (five patients), during squeeze (one patient), or both (one patient). Opening and closing pressures of the sphincter at rest, maximal closing pressure during squeeze, and anal hysteresis were normal. Standard anal manometry did not show any differences between patients and controls. Rectal compliance was lower in patients with obstructed defecation, median difference 5 ml/cm H2O (95 percent confidence limits, 1-9 ml/cm H2O). In conclusion, the more detailed method of dynamic anal manometry shows that some patients with obstructed defecation have a less compliant anal sphincter and a less compliant rectum, but in many patients no abnormal findings can be made.

Adult↗

Manometric patterns of rat colonic motor activity and defecation. Effect of selective 5HT1A agonist 8-OH-DPAT.

We investigated in conscious and unrestrained rats, the major patterns of colonic pressure waves, as related to defecation. A manometric low compliance perfusion system, which was set at a very low flow rate (0.03 ml/min), permitted simultaneous recordings of intraluminal pressure in the proximal, transverse, and distal colon. Pressure waves in control rats reflected two types of motor activity: short-duration waves (< 15 sec), that were frequent throughout the colon (about 40-90/hr with aborally decreasing frequency), and propulsive, long-duration, high-amplitude waves (> 15 sec, > 15 mm Hg) that occurred only occasionally (1/hr or less) in the transverse and distal, but not in the proximal colon; these waves appeared to migrate aborally and were associated with defecation. The serotonin 5HT1A agonist 8-OH-DPAT dramatically and dose-dependently increased the frequency of long-duration, high-amplitude waves in the transverse and distal colon, and concurrently promoted defecation; these effects were prevented by the putative 5HT1A antagonist pindolol. We conclude that 5HT1A agonists such as 8-OH-DPAT may promote defecation and occurrence of propulsive waves through the same serotoninergic mechanism.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Obstructed defecation after undiverted ileoanal pouch reconstruction for ulcerative colitis: pharmacologic approach. Report of a case.

PURPOSE: Obstructed defecation after ileal pouch construction has been reported only after closure of the diverting loop ileostomy, and biofeedback was an effective treatment modality. METHOD: This is a case report of a patient with immediate obstructed defecation after ileal pouch-anal anastomosis without a covering loop ileostomy and its successful pharmacologic management. RESULTS: A 38-year-old female underwent restorative proctectomy and stapled ileal J-pouch-anal anastomosis without a covering loop ileostomy. On the seventh postoperative day, her pouch catheter (in lieu of a covering loop ileostomy) was removed and she failed to evacuate. After ruling out any technical complications, diltiazem was commenced with successful spontaneous pouch emptying. Obstructed defecation reoccurred after cessation of diltiazem one week later, but the symptoms resolved once the diltiazem was recommenced. CONCLUSIONS: Obstructed defecation has been reported in patients after pelvic pouch reconstruction. However, in all those patients a diverting loop ileostomy had been raised and their obstructive symptoms were only apparent after closure of the ileostomy and when the pouch had healed. The concern regarding our patient was the complete outlet obstruction so soon after surgery, with undue strain on the anastomosis and the potential risk of disruption. Our only two options were either to create a diverting loop ileostomy or to try a fast-acting pharmacologic agent (diltiazem) to treat the presumed levator spasm. The latter option spared the patient a further operation.

Administration, Oral↗

Self washout method for defecational complaints following low anterior rectal resection.

A self washout method was performed by ten patients who had defecational complaints following an anterior resection. A commercially available colostomy washout set was used for this procedure. When the patient sat down, the cone tip of the set was pressed into the anal canal by pushing the cone with the palm of the hand. The volume of water for irrigation used was 500 to 1000 ml and the subsequent defecation time was from 20 to 50 minutes. In all cases, the frequent urge to defecate disappeared and after normal defecational function had been recovered, the self washout was able to be discontinued.

Adult↗

Effects of neonatal castration and testosterone injection on adult open-field behaviour in rats with atypical sex difference in defecation.

In the open-field test, male rats usually defecate more and ambulate less than females. A strain was studied in which the males defecate less than females, while still ambulating less. Infants of this strain were castrated (males) or injected with testosterone propionate (females) and tested in the open field as adults. There were significant effects of these neonatal treatments on ambulation, but not on defecation, in contrast to previous reports for the latter measure in rats showing a sex difference in defecation taking the usual direction. It is suggested that absence of the usual direction of a sex difference normally under the developmental control of androgen may indicate a genotype which has escaped from such control. Finally, a number of 'sibling' effects' were observed, i.e. effects on the adult behaviour of the members of one sex in a litter produced by treatments administered in infancy to members of the other sex.

Animals↗

Impairment of defecation in young women with severe constipation.

Anorectal manometry, radiology, and tests of simulated defecation were carried out in 14 severely constipated young women and 29 age-matched controls. The resting anal sphincter pressures were reduced in the patients, but the squeeze pressures, rectoanal inhibitory reflex, and rectal pressures upon balloon distention were all normal. At rest, the anorectal angle was more obtuse in the constipated group, but there was no overall increase in perineal descent in constipated patients compared with controls. The presence of a balloon in the rectum and the onset of pain were perceived in constipated patients at volumes that were not significantly different from those in normal volunteers. Constipated patients, however, required higher rectal volumes to induce the desire to defecate and to stimulate regular rectal contractions. Constipated patients also found it more difficult to pass simulated stools from the rectum than the normal controls and, unlike most normal controls, failed to inhibit their external anal sphincter on attempted defecation. These findings suggest that young women with severe constipation have great difficulty initiating the coordinated set of events that constitute a normal defecation response.

Adolescent↗

alpha-MSH effects on novelty-induced defecation, plasma 11-OHCS and whole brain catecholamines in hypophysectomized rats.

The effect of hypophysectomy on novelty-induced defecation was found to be inhibitory in nature, but this effect was reversed by treatment with alpha-MSH. MSH-treated hypox rats maintained, over days, novelty-induced defecation and showed a significant elevation in plasma 11-OHCS levels, compared with the levels of control-injected counterparts. MSH treatment also reduced over Days 1 to 5 the whole brain DA and whole brain NE levels in hypox animals. Control-treated hypox rats, however, showed an increase in brain NE concentration which was significantly reduced by MSH treatment. Sham-hypox animals also sustained novelty-induced defecation after MSH treatment but did not show a significant rise in plasma 11-OHCS level. Whole brain DA and whole brain NE levels in sham-hypox rats were also reduced significantly by MSH treatment. The behavioral maintenance of defecation in hypox and sham-hypox rats seem to be concomitant with significant reductions in whole brain catecholamines.

11-Hydroxycorticosteroids↗

Effects of alpha-MSH and melatonin on passive avoidance and on PA-induced defecation and plasma 11-OHCS in hypophysectomized rats.

The present study shows tha alpha-MSH facilitates the acquisition and delays the extinction of a Passive Avoidance Response (PAR) in the hypox animals. MSH exacerbates PA-induced defecation in both hypox and sham-hypox animals. Hypox and sham-hypox animals treated with MSH do not differ on PAR or on PA-induced defecation. Melatonin, on the other hand, has no significant effect on PAR in hypox rats, but retards acquisition and facilitates extinction of the PAR in sham-hypox rats. Melatonin also inhibits PA-induced defecation in sham-hypox rats. Sham-hypox and hypox rats treated with Melatonin do not differ on PAR learning, retention (Extinction) and PA-induced defecation. MSH and Melatonin also seem to have opposite effects on plasma 11-OHCS levels measured at the end of PAR extinction. MSH increases plasma 11-OHCS in hypox rats, whereas Melatonin decreases plasma 11-OHCS in sham-hypox rats. Melatonin does not lower further the very low level of plasma 11-OHCS in hypox rats.

11-Hydroxycorticosteroids↗

alpha-MSH, MIF-I and melatonin: effects on novelty-induced defecation, plasma 11-OHCS and central catecholamines in rats.

The pituitary-hypothalamo-pineal complex involving MSH, MIF-I and melatonin has been strongly emphasized in the adaptive mechanism of the animal. A series of experiments was conducted to investigate the effects of alpha-MSH, MIF-I and melatonin on novelty-induced defecation, step-down activity, plasma 11-OHCS levels and whole brain DA and NE concentrations over days of novelty X drug treatment. alpha-MSH consistently enhanced and sustained novelty-induced defecation, increased plasma 11-OHCS levels in the resting intact rats and in the novelty exposed hypophysectomized (hypox) rats, and decreased brain DA and NE levels in intact, hypox and sham-hypox rats. MSH did not increase plasma 11-OHCS in intact and sham-hypox rats during exposure to novelty. MIF-I significantly habituated novelty-induced defecation and increased brain DA and NE levels over 5 days of drug X novelty treatment. Melatonin, on the other hand, inhibited novelty-induced defecation, decreased plasma 11-OHCS and increased brain DA level over 5 days of melatonin X novelty treatment. MSH, MIF-I or melatonin did not show any significant effect on the step-down activity of the rats. The results suggest the possibility that central CAs may be implicated in the behavioral changes observed after alpha-MSH, MIF-I and melatonin administration and in the interaction of the pituitary-hypothalamo-pineal complex involving MSH, MIF-I and melatonin.

11-Hydroxycorticosteroids↗

Defecation practices of young children in a Peruvian shanty town.

Little is known about feces disposal practices, their determinants and feasibility for change, despite their importance in the control of diarrheal diseases. We report here the results of formative research for the development of an intervention to promote sanitary disposal of feces of young children. The study was conducted in a densely populated shanty town area of Lima, where water and sanitation systems are scarce. In-depth interviews were undertaken with mothers, husbands and community leaders. Group discussions were held with mothers in order to validate findings from the interviews, investigate particular topics further and explore reactions to possible intervention strategies. The principal defecation sites for young children were diapers, potties, the ground in or near the home, the hill, latrines and flush toilets. The main determinants found were the age of the child, the effort required by the method, perceptions of dirtiness and the availability of resources. Almost all children under one year of age use diapers but the high resource cost of diaper washing is a strong motivation for mothers to move their children on as early as possible. Potties were considered the most socially acceptable and 'hygienic' defecation method for children between one and three years of age. Nevertheless, defecation directly onto the ground is common at this age. Potty training is deemed to be quite difficult and the long term achievements are determined by the initial training success. In most cases, the training process is authoritative and inconsistent. The use of latrines and flush toilets is not considered appropriate for children until they are three to four years old. Based on these initial findings, a micro-trial was conducted to assess the feasibility and acceptability of promoting greater use of potties and associated practices. The results of the trial were very encouraging and provided valuable information for the design of a community-wide intervention. Our findings help explain why the emphasis given in most sanitation projects, where efforts have been concentrated on the promotion of latrines, has failed to induce their utilization by small children. Sanitation projects should incorporate interventions that will promote hygienic defecation and stool clearance practices for infants and small children.

Child↗

An ion channel of the degenerin/epithelial sodium channel superfamily controls the defecation rhythm in Caenorhabditis elegans.

Ultradian rhythms are widespread phenomena found in various biological organisms. A typical example is the defecation behavior of the nematode Caenorhabditis elegans, which repeats at about 45-sec intervals. To elucidate the mechanism, we studied flr-1 mutants, which show very short defecation cycle periods. The mutations also affect some food-related functions, including growth rate, the expulsion step of defecation behavior, and the regulation of the dauer larva (a nonfeeding, special third-stage larva) formation in the unc-3 (Olf-1/EBF homolog) background. The flr-1 gene encodes a novel ion channel belonging to the DEG/ENaC (C. elegans degenerin and mammalian epithelial sodium channel) superfamily. A flr-1::GFP (green fluorescent protein) fusion gene that can rescue the flr-1 mutant phenotypes is expressed only in the intestine from embryos to adults. These results suggest that FLR-1 may be a component of an intestinal regulatory system that controls the defecation rhythm as well as other functions.

Activity Cycles↗

Obstructed defecation: current status of pathophysiology and management.

Obstructed defecation poses a challenging clinical problem and in many patients presenting with this syndrome the underlying pathophysiology cannot be determined. Up to now, attempts to diagnose and treat obstructed defecation (anismus) have focused on the function of the somatic pelvic floor musculature surrounding the anorectum, and concepts such as 'puborectalis paradox' and 'spastic pelvic floor' have gained widespread acceptance despite there being no objective data to support such concepts. New evidence showing that defecation is an integrated process of colonic and rectal emptying suggests that anismus may be much more complex than a simple disorder of the pelvic floor muscles. In a small number of patients obstructed defecation is caused by a more simple mechanism, such as internal sphincter hypertonia or a large rectocele, which is easily corrected surgically. Careful selection of patients for treatment, based on identifying the underlying pathophysiological disorder, is emphasized.

Anal Canal↗

Current techniques of assessing defecation dynamics.

The pathophysiology of defecation disorders is multifactorial. An ideal test should identify the underlying cause(s) and provide guidelines for treatment. Unfortunately, there is no such single test. But several techniques are available that could provide comprehensive information regarding the changes in defecation dynamics. Among these, anorectal manometry offers the most useful test for clinicians. Manometry may provide objective evidence for impaired rectal sensation, poor rectoanal coordination, weak anal sphincters or changes that support a diagnosis of obstructive defecation. Other tests such as the balloon expulsion test may serve as screening tools for patients with constipation. In a patient with fecal incontinence, anal endosonography may localize the sphincter defect and aid surgical reconstruction. The pudendal nerve latency test may provide a pathophysiological basis for a weak anal sphincter. Imaging techniques such as defecography may provide useful information regarding rectal prolapse or levator ani dysfunction. Ideally, the clinician should utilize these tests either to confirm a clinical suspicion or to provide new information that could aid management. This review provides an update regarding the various tests that are available for assessing defecation and provides some practical guidelines for performing manometry.

Anal Canal↗

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↗