Rectocele repair with stapled transvaginal rectal resection.

BACKGROUND: Constipation is a clinical symptom in patients suffering from slow transit and/or obstructed defecation. Proper treatment requires the identification of all associated disorders and the quantification of symptoms. Rectocele can cause the symptoms of obstructed defecation syndrome (ODS). The aim of this study was to evaluate the clinical and functional outcomes of a novel technique of transvaginal stapled rectal resection (TVSRR) using a straight staple line, to treat rectocele. METHODS: The study included 84 females [median age 51 years (range 29-73 years)], with obstructed defecation, grades II-III rectocele, and multiple abnormalities on defecography. The magnitude and degree of ODS were quantified by the Altomare ODS scoring system. Continence status was evaluated using the Pescatori scoring system. The rectal and vaginal manometric study, the index of patient satisfaction using a visual analog score (VAS), and the validated Patient Assessment of Constipation Quality of Life (PAC-QOL) questionnaire results were recorded. All patients underwent TVSRR. RESULTS: There were no intraoperative complications. Early postoperative complications were defecatory urgency in seven patients (8.3 %), dyspareunia in two (2.4 %), and rectovaginal fistula in one (1.2 %). Five patients (6 %) had recurrence of ODS symptoms. There was no significant change in continence pre- and postoperatively. The ODS score and VAS revealed significant improvement within the first postoperative year in 94 % of patients. The PAC-QOL questionnaire mean total scores indicated an improvement in both the patient satisfaction and the QOL during the 12-month follow-up. The self-reported definitive outcome was excellent in 46 patients (54.7 %), good in 29 (34.5 %), fairly good in 20 (23.8 %), and poor in five (6.0 %). CONCLUSIONS: Vaginal repair carries no risk of fecal incontinence. Large anterior rectocele is considered the main indication for this technique. Using the linear stapler is a cost-effective, simple, and easy technique.

Combined partial fistulectomy and electro-cauterization of the intersphincteric tract as a sphincter-sparing treatment of complex anal fistula: clinical and functional outcome.

BACKGROUND: The aim of this study was to report a simple, effective and safe procedure, associated with minimal risk of incontinence and recurrence, for treating complex anal fistulas. METHODS: This was a prospective study of 53 consecutive patients with complex anal fistulas. The technique used included excision of the distal part of the fistula tract down to the external anal sphincter and electro-cauterization of the intersphincteric part of the tract with simple closure of the internal opening. Data collected included patient characteristics, fistula type determined by magnetic resonance imaging, pre- and postoperative continence status evaluated using the Wexner incontinence score (0-10), previous operations, hospital stay, healing time, recurrence rate and complications. RESULTS: The patients had a mean age of 41.37 ± 7.82 years; the most frequent fistula type was the high transsphincteric fistula; the mean follow-up period was 19 months with a success rate of 92.5 %; the mean wound healing time was 3.6 weeks; the incontinence scores were the same as before the procedure. The recurrence rate was 7.5 %. CONCLUSIONS: Partial fistulectomy combined with electrocauterization of the intersphincteric fistula tract is a simple, and effective procedure for the treatment of complex anal fistulas.

Electromyographic study of ejaculatory mechanism.

Cavernosus muscle (CM), seminal vesicle (SV) and vasal ampullary (VA) contractions at ejaculation are said to be reflex mechanisms (ejaculatory reflex), which have been scarcely dealt with in the literature. We investigated the hypothesis that contraction of the CMs, SVs and VA at ejaculation is a reflex action. The electromyographic (EMG) activity of CM, SV and VA during ejaculation was recorded in 28 healthy men. The test was repeated after separate anaesthetization of the glans penis (GP), CMs, SVs, and VA in the pre-ejaculatory period. Latent ejaculatory time (LET) was calculated. CMs showed no EMG activity until rigid erection phase was reached. SVs and VA exhibited resting EMG activity which increased gradually with different stages of erection. At ejaculation, CMs, SVs and VA showed two to four intermittent contractions. The mean LET was 1.3 +/- 0.2 sec. GP anaesthetization led to the disappearance of CM, SV and VA EMG activity at ejaculation, while bland gel did not affect EMG activity. CMs, SVs and VA when anaesthetized in the pre-ejaculatory period exhibited no EMG activity at ejaculation, while saline did not affect EMG activity. Increased EMG activity of CM, SV and VA apparently denotes increase in their contractile activity. CM, SV and VA contraction on GP stimulation and ejaculation are assumed to be reflex actions and are mediated through the 'glans-cavernosovesicular reflex' (GCVR) which presumably represents the ejaculatory reflex. Changes in LET or evoked response would indicate a defect in the reflex pathway. The GCVR might act as an investigative tool in diagnosing erectile dysfunction, provided further studies are performed in this respect.

A study of the effect of straining on the cavernosus muscles: identification of 'straining-cavernosus reflex' and its clinical significance.

Bulbo/ischiocavernosus muscles (BCM, ICM) were found to contract on straining. We investigated the hypothesis that straining effects cavernosus muscles' contraction through a reflex action. The response of the BCM and ICM electromyographic (EMG) activity to increased intra-abdominal pressure (straining) as recorded by the intravesical pressure was registered in 32 healthy volunteers (age 39.2 +/- 10.3 years, 20 men, 12 women). The latency of the response was recorded. Responses were registered again in 17 subjects after individual anaesthetisation of urinary bladder, BCM, and ICM. BCM and ICM EMG activity increased progressively with increasing straining. It was not evoked after frequent successive straining. Latency decreased gradually with increase of straining intensity. Cavernosus muscles did not respond to straining after bladder and cavernosus muscles had been individually anaesthetised. Straining appears to effect cavernosus muscles' contraction through the 'straining-cavernosus reflex'. Cavernosus muscles' contraction produces compression of the penile and clitoral cavernous tissue. BCM contraction, furthermore, causes narrowing or closure of the vaginal introitus. The vagina is suggested to become a high pressure closed cavity which counteracts the increased intra-abdominal pressure and uterine tendency to prolapse. Meanwhile, the elevated intravaginal pressure presumably supports the rectovaginal septum against the concomitant high intrarectal pressure.

Identification of a vaginal pacemaker: An immunohistochemical and morphometric study.

Vaginal electric waves spread caudally in the vagina. We investigated the hypothesis that electric waves originate from a centre of interstitial cells of Cajal (ICCs) in the proximal vagina. Specimens (0.75 x 0.75 cm) were obtained from the vaginal walls of 23 cadavers (age 38.2 +/- 10.2 years). Sections were prepared for immunohistochemical investigations using the specific ICC marker, C-kit. Morphometric studies for image analysis using a Leica imaging system were performed. C-kit positive cells were detected in vaginal smooth muscle. Results from image analyser revealed that mean area percent of positive immunoreactivity for C-kit in the upper part of posterior vaginal wall was significantly higher (p < 0.0001) than of areas in other vaginal walls, and also significantly higher (p < 0.05) in circular than in longitudinal muscle layer. Studies have shown that the greatest collection of ICCs occurred in the upper part of the posterior vaginal wall. The vaginal electric waves are suggested to originate from this 'centre' and spread caudally.

Effect of cooling on the rectal tone.

OBJECTIVES: It has been claimed that recognizable organized sensory nerve endings could not be detected in the rectal wall. Hence the identification of cold receptors sensitive to cold temperature in the rectal wall has so far not been reported in the literature. We investigated the hypothesis that rectal cooling effected an increase of the rectal tone. METHODS: Twenty-eight healthy volunteers (18 men, 10 women, age 26-50 years) were studied. The rectal wall tone was assessed by the barostat system during infusion of normal saline at 30 degrees C and at 4 degrees C. The test was repeated after rectal anesthetization with lidocaine. RESULTS: The rectal tone on rectal saline infusion showed no response at a temperature of 30 degrees C, and asignificant increase (p < 0.05) at 4 degrees C. The latency measured by the switch-inflation apparatus recorded a mean of 15.3 +/- 1.2 ms. Iced saline infusion into the anesthetized rectum effected no significant change in the rectal tone. CONCLUSIONS: The current study has demonstrated that rectal infusion of iced saline produced an increase of the rectal tone. This effect is suggested to be a reflex and mediated through the 'rectal cooling reflex'. The reflex is suggested to act as an investigative tool in the diagnosis of rectal motile disorders provided further studies are performed.

Rectal cooling test in the differentiation between constipation due to rectal inertia and anismus.

BACKGROUND: The differentiation between constipation due to rectal inertia and that due to outlet obstruction from non-relaxing puborectalis muscle (PRM) is problematic and not easily achieved with one diagnostic test. Therefore, we studied the hypothesis that the rectal cooling test (RCT) can effectively be used to differentiate between those two forms of constipation. METHODS: The study enrolled 28 patients with constipation and abnormal transit study in whom radio-opaque markers accumulated in the rectum; 15 healthy volunteers acted as controls. Electromyographic activity of the external anal sphincter (EAS) and PRM was initially recorded. Subsequently rectal wall tone was assessed by a barostat system during rectal infusion with normal saline at 30 degrees C and at 4 degrees C with simultaneous electromyography (EMG). RESULTS: There was a significant increase in EMG activity of the EAS and PRM on strain- ing (p<0.001), suggestive of anismus, in 10 of 28 patients and 0 of 15 controls. Rectal tone in controls did not respond to saline infusion at 30 degrees C, but it increased at 4 degrees C (p<0.05). Similarly, in constipated patients rectal tone did not respond to rectal saline infusion at 30 degrees C, but infusion at 4 degrees C increased tone in all 10 patients with anismus (p<0.05); EMG activity of the EAS and PRM also increased (p<0.001). In the remaining 18 patients, rectal tone after saline infusion at 4 degrees C remained unchanged. CONCLUSIONS: Rectal infusion with iced saline increased rectal tone in healthy controls and constipated patients with anismus while it had no effect in the remaining patients. Lack of increase of rectal tone may be secondary to rectal inertia. According to these preliminary observations, the rectal cooling test may be useful in differentiating between rectal inertia and anismus.

Vaginal and uterine pressure response to semen deposition into the vagina and uterus: human study.

PURPOSE OF INVESTIGATION: The effect of semen deposition in the vagina or uterine cavity on both uterine and vaginal pressure has scarcely been reported in the literature. We investigated the hypothesis that semen deposition in the vagina or uterus effects changes in their pressure. METHODS: The study comprised 27 healthy women volunteers (mean age 36.4 +/- 11.6 years). Both uterine and vaginal pressure were measured under basal conditions and on semen or saline deposition in the vagina and uterus. RESULTS: Upon semen deposition in the vagina, the vaginal pressure showed no significant changes (p > 0.05) while the uterine pressure exhibited a significant intermittent rise (p < 0.05). Semen deposition into the uterine cavity caused no vaginal pressure changes (p > 0.05) while the uterine pressure exhibited an intermittent increase (p < 0.01). Saline injection into the vagina or uterus showed no significant pressure changes (p > 0.05). CONCLUSION: Semen deposition into the vagina or uterine cavity was associated with uterine pressure elevation that might eventually help transport the sperm to the oviduct. Further studies are required to define the substances responsible for this effect.

Interstitial cells of Cajal in erectile dysfunction.

The corpora cavernosa (CC) evokes electric activity. Slow waves (SWs) appear to originate from interstitial cells of Cajal (ICCs), which seem to control the activity of the smooth muscle cells (SMC). The ICCs were demonstrated to exist in the CC. We investigated the hypothesis that the ICC distribution differs with each of the various ED types. The study comprised 62 men with ED: 16 neurogenic (NGED), 15 arteriogenic (AGED), 11 venogenic (VGED) and 22 psychogenic (PGED). 15 volunteers with normal erections acted as controls. The patients underwent a complete diagnostic evaluation. A biopsy of 3 x 3 mm from the CC was subjected to C-kit immunohistochemistry examination. Specificity control of the antisera consisted of incubation of the tissue with normal rabbit serum substituted for the primary antiserum. C-kit positive stellate-appearing cells resembling those of ICC were detected in the controls. The branches were either laterally located (multipolar) or lying at each pole (bipolar). They were distinguishable from the SMC, which were C-kit negative. ICC were detected in all specimens from patients with NGED and VGED, absent in 13/15 with AGED and scanty in PGED. ICC distribution was different in the various types of ED. It is suggested that this distribution interferes with SW discharge and the control of SMC activity with a resulting ED.

Molecular andrology as related to sperm DNA fragmentation/sperm chromatin biotechnology.

Genetic male infertility occurs throughout the life cycle from genetic traits carried by the sperm, to fertilization and post-fertilization genome alterations, and subsequent developmental changes in the blastocyst and fetus as well as errors in meiosis and abnormalities in spermatogenesis/spermatogenesis. Genes encoding proteins for normal development include SRY, SOX9, INSL3 and LGR8. Genetic abnormalities affect spermatogenesis whereas polymorphisms affect receptor affinity and hormone bioactivity. Transgenic animal models, the human genome project, and other techniques have identified numerous genes related to male fertility. Several techniques have been developed to measure the amount of sperm DNA damage in an effort to identify more objective parameters for evaluation of infertile men. The integrity of sperm DNA influences a couple's fertility and helps predict the chances of pregnancy and its successful outcome. The available tests of sperm DNA damage require additional large-scale clinical trials before their integration into routine clinical practice. The physiological/molecular integrity of sperm DNA is a novel parameter of semen quality and a potential fertility predictor. Although DNA integrity assessment appears to be a logical biomarker of sperm quality, it is not being assessed as a routine part of semen analysis by clinical andrologists. Extensive investigation has been conducted for the comparative evaluation of these techniques. However, some of these techniques require expensive instrumentation for optimal and unbiased analysis, are labor intensive, or require the use of enzymes whose activity and accessibility to DNA breaks may be irregular. Thus, these techniques are recommended for basic research rather than for routine andrology laboratories.

Sperm DNA fragmentation.

Several techniques have been developed to measure the amount of sperm DNA damage in an effort to identify more objective parameters for evaluation of infertile men. The integrity of sperm DNA influences a couple's fertility and helps predict the chances of pregnancy and its successful outcome. The available tests of sperm DNA damage require additional large-scale clinical trails before their integration into routine clinical practice. The physiological/molecular integrity of sperm DNA is a novel parameter of semen quality and a potential fertility predictor. Although DNA integrity assessment appears to be a logical biomarker of sperm quality, it is not being assessed as a routine part of semen analysis by clinical andrologists. Extensive investigation has been conducted for the comparative evolution of these techniques. However, some of these techniques require expensive instrumentation for optimal and unbiased analysis, are labor intensive, or require the use of enzymes whose activity and accessibility to DNA breaks may be irregular. Thus, these techniques are recommended for basic research rather than for routine andrology laboratories. Sperm chromatin structure evaluation is applied to detect male factors that may affect the chance of success with IVF as well as natural fertility. Further research is needed to define the optimal test of sperm chromatin structure. The clinical application of this test will evolve as well.

Role of tunica albuginea in erection: is it a dynamic or a static role?

The tunica albuginea (TA) of the penis is claimed to share in erectile mechanism by compressing the emissary veins passing through it. Apparently this claim is theoretical as no experimental studies could be traced in literature proving this concept. We investigated the hypothesis that TA acts as a cover to corpora cavernosa (CC) and spongiosa (CS) and does not have an active role in erectile mechanism. Penises of 9 dogs were degloved and TA was divided at upper, middle and lower 1/3 of the penis. The intracorporal and glans penis (GP) pressures were measured in the TA-covered and non-covered parts of CC and CS in the flaccid and erectile phases. Sham operation, without performing the TA incisions, was done in 7 control animals. In the test animals, intracorporal pressure (ICP) in the non-TA covered corpora and in GP recorded in flaccid phase a mean of 12.2 +/- 0.8 cmH2O for CC and 11.3 +/- 0.7 cmH2O for the CS and GP, and in the erectile phase 98.4 +/- 8.6 and 76.2 +/- 9.3 cmH2O, respectively. There was no significant difference between covered and non-covered corpora or between test and control animals. In conclusion, the TA seems to act as a cover to the corporal tissue. Its absence did not change ICP.

Tunica albuginea overlapping: a novel technique for the treatment of erectile dysfunction.

Tunica albuginea (TA) in venogenic erectile dysfunction (VED) was found subluxated and flabby because of degeneration and atrophy of its collagen fibres. This had apparently led to derangement of TA veno-occlusive mechanism. We investigated the hypothesis that overlapping of the subluxated and flabby TA would achieve a competent veno-occlusive mechanism during erection. Tunical overlapping was performed in nine VED patients (age 35.6 +/- 1.6 years). Intracorporal pressure (ICP) was measured pre- and postoperatively. After penile degloving, TA on lateral penile aspect was divided along whole length of corpus cavernosum (CC) and tunical double-breasting for 1-1 1/2 cm was performed. A biopsy was taken from TA and stained with haematoxylin and eosin and Masson's trichrome. Clinical efficiency of the operation was evaluated after 6 months. ICP increased (P < 0.01) postoperatively in the nine patients. The increase was maintained during follow-up period in eight patients and decreased to preoperative level in one. Six months after operation, the eight patients had significantly (P < 0.01) improved scores for the erectile function domain over the preoperative scores. Microscopic examination of TA biopsies showed atrophy of the collagen fibres. Tunical overlapping aims at correction of TA flabbiness, corporal tissue support and improving of veno-occlusive mechanism.

Urethral sphincters response to cavernosus muscles stimulation with identification of cavernoso-urethral reflex.

The functional activity of the urethral sphincters during cavernosus muscles' contraction at coitus has been poorly addressed in the literature. We investigated the hypothesis that cavernosus muscles' contraction affects reflex contraction of the urethral sphincters to guard against semen reflux into the urinary bladder or urine leakage from the bladder during orgasm and ejaculation. The electromyographic (EMG) response of the external (EUS) and internal (IUS) urethral sphincters to ischio- (ICM) and bulbo- (BCM) cavernosus muscle stimulation was studied in 15 healthy volunteers (9 men, 6 women, age 39.3 +/- 8.2 SD years). An electrode was applied to each of ICM and BCM (stimulating electrodes) and the 2 urethral sphincters (recording electrodes). The test was repeated after individual anesthetization of the urethral sphincters and the 2 cavernosus muscles, and after using saline instead of lidocaine. Upon stimulation of each of the 2 cavernosus muscles, the EUS and IUS recorded increased EMG activity. Repeated cavernosus muscles' stimulation evoked the urethral sphincteric response without fatigue. The urethral sphincters did not respond to stimulation of the anesthetized cavernosus muscles nor did the anesthetized urethral sphincters respond to cavernosus muscle stimulation. Saline infiltration instead of lidocaine did not affect the urethral sphincteric response to cavernosal muscle stimulation. Results were reproducible. Cavernosus muscles' contraction is suggested to effect EUS and IUS contraction. This action seems to be reflex and mediated through the 'cavernoso-urethral reflex.' Urethral sphincters contraction upon cavernosus muscles contraction during sexual intercourse presumably prevents urine leak from the urinary bladder to urethra, prevents retrograde ejaculation, and propels ejaculate from the posterior to the penile urethra. The cavernoso-urethral reflex can act a diagnostic tool in the investigations of patients with ejaculatory disorders.

Identification of c-kit-positive cells in the human prostate: the interstitial cells of Cajal.

The prostate exhibits electric activity in the form of slow waves (SWs) and action potentials (APs). As the interstitial cells of Cajal (ICCs) are considered the pacemaker cells which generate the electric waves, we investigated the hypothesis that the prostate contains ICC. Prostatic biopsies were obtained from 15 healthy volunteers (mean age 36 +/- 3.8 SD years). They were subjected to c-kit immunohistochemistry. Controls for the specificity of the antisera consisted of tissue incubated with normal rabbit serum substituted for the primary antiserum. C-kit-positive cells were identified as fusiform with dendritic processes. The cytoplasm was granular and the nucleus large and oval. Mast cells, also c-kit-positive, were round and lacked the dendritic processes. Immunoreactivity was absent in the negative controls. There were cells in the prostate with morphological and immunological phenotypes similar to ICCs of the gut. We predict an abnormal distribution of these cells in prostatic diseases. The study of the integrity of these cells may prove to be a useful investigative tool in the diagnosis of prostatic diseases and in the planning of an appropriate treatment.

Overactive corpus cavernosum: a novel cause of erectile dysfunction.

Our recording of the electromyographic (EMG) activity of the corpus cavernosum (CC) in 59 patients with erectile dysfunction (ED) revealed 18 patients who had elevated electric activity, which presumably points to heightened tone of the CC smooth muscles. We investigated the hypothesis that this elevated EMG activity and muscular tone of the CC could be the cause of ED. The study comprised the said 18 subjects with the hypertonic CC muscles as study group (42.6 +/- 5.3 SD years), 15 healthy volunteers (41.8 +/- 5.1 SD years) and 15 patients (41.6 +/- 5.5 SD years) with ED who had not recorded elevated tone of the CC muscles as control group. The EMG activity was registered in the flaccid, erectile and detumescent phases by two electrodes inserted into the CC. Electrocavernosography (ECG) of healthy volunteers recorded in the flaccid phase showed regular slow waves (SW) and random action potentials (APs). The wave variables declined significantly in the erection phase (P < 0.01). In the study group, the SW variables in the flaccid phase increased significantly (P < 0.05) compared with the healthy volunteers and the rhythm was irregular. Erection did not occur with sildenafil but with intracavernosal injection of papaverine, which led to decline of the SW variables (P < 0.05). The control ED group exhibited in the flaccid phase diminished SW variables (P < 0.05) compared with the healthy volunteers. On erection with sildenafil administration, the SW variables showed significant reduction (P < 0.05). CC hypertonicity or 'overactive CC' was identified as a possible cause of ED. An elevated EMG activity of the CC muscle fibres in the flaccid phase presumably denotes hypertonicity of these fibres and their failure to relax to effect erection. The cause of elevated CCEMG activity and presumed muscle hypertonicity is unknown and could be functional or organic. Erection was produced by intracavernosus injection of papaverine and not by sildenafil. This condition of 'overactive CC' should be considered in the diagnosis of ED. However, further studies in the pathogenesis of the condition are warranted.

Electromotor activity of the cecum and ascending colon: the concept of 'individual pacemakers'.

BACKGROUND/AIMS: The cecum is described as differing anatomically from the ascending colon (AC); yet their similarity or difference in terms of motile activity has not been studied sufficiently. The cecum is separated from the AC by the cecocolonic junction (CCJ) which contains a cecocolonic sphincter. We assumed that the motile activity of the AC is different from that of the cecum and hypothesized that both the AC and the cecum might have different pacemakers which initiate the motile activity. This hypothesis was investigated in the current study. METHODS: The study was performed in 10 subjects (mean age 41.6 +/- 12.8 SD years; 7 women) during the repair of huge abdominal incisional hernias. The electric activity was recorded from 2 monopolar electrodes applied each to the cecum, CCJ and AC. The CCJ was then anesthetized by xylocaine and the electric waves of the cecum, CCJ and AC were registered after 10 and 90 min. The test was repeated using normal saline instead of xylocaine. RESULTS: Electric waves were recorded from the cecum, CCJ and AC in the form of monophasic pacesetter (PPs) and action potentials (APs). The PPs occurred regularly and the APs randomly. The frequency, amplitude and conduction velocity of the waves recorded from the CCJ and AC had higher readings than those from the cecum (p < 0.05). The CCJ and AC showed similar frequency and conduction velocity (p > 0.05). Ten minutes after CCJ anesthetization, electric waves were recorded from the cecum but not from the CCJ or AC; however, electric activity returned after 90 min. Saline injection did not affect the electric activity of the cecum, CCJ and AC. CONCLUSION: The electric wave parameters of the cecum differed from those of the CCJ and AC, suggesting that the motile activity of the CCJ and AC is not a continuation of the motile activity of the cecum and that it might be evoked by 2 different pacemakers. The similarity in frequency and conduction velocity of electric waves of the CCJ and AC, however, most likely denotes that the AC waves are a continuation of those of the CCJ, and that both are evoked by the same pacemaker probably located in the CCJ. The higher amplitude of cecal waves might be due to the thicker cecal musculature compared to that of the AC.

Study of the mechanism of rectal motility: the 'mass squeeze contraction'.

The motor physiology of the rectum has remained largely obscure, especially concerning the mechanism of rectal motility. In the current communication we tested the possibility of characterizing the mechanism of rectal motility during filling and evacuation through the study of the rectal electric activity in 16 healthy volunteers (mean age 43.6 +/- 10.8 years; 11 men). Two monopolar silver-silver chloride electrodes were introduced per annum and fixed to the rectal mucosa by suction. The rectum was distended in 10 ml increments of water by means of a balloon-ended catheter inserted into the rectum. The rectal pressure was measured by one catheter placed above and a second one below the rectal balloon, and the 2 catheters were connected to 2 strain gauge pressure transducers. Regular triphasic slow waves or pacesetter potentials (PPs) were recorded from the 2 electrodes at rest. PPs were superimposed or followed randomly by action potentials (APs). APs but not PPs were coupled with elevated rectal pressure. Rectal distension with 10 ml of water caused no significant changes of the rectal pressure or EMG activity. Distension with a mean volume of 27.3 +/- 4.7 ml effected a significant increase (p < 0.05) of the rectal electromechanical activity proximally to the balloon and a decrease distally (p < 0.05) to it. With progressive increase of the rectal distension, the electromechanical activity continued to increase proximally and to decrease distally to the balloon, until, at a mean distending volume of 76.3 +/- 3.7 ml, the balloon was dispelled to the exterior. In conclusion, the identification of the modality of rectal motility during defecation was feasible by recording the rectal electromechanical activity. The rectal contraction is suggested to occur in a 'mass squeeze manner' which squeezes the rectal contents aborally into the anal canal. The recognition of the rectal motor modality appears to be important for the understanding of rectal motility disorders. However, further studies are required to confirm these findings.

Study of the effect of temperature on the rectal function with evidence of thermorectal reflex.

BACKGROUND AND AIMS: Rectal sensation seems to originate from mechanoreceptors which are stimulated by passive rectal filling or active contraction. We investigated the effect of temperature on rectal function. PATIENTS AND METHODS: A balloon was introduced into the rectum of 28 healthy volunteers, filled with 50 ml saline at various temperatures, and rectal pressure was recorded. The test was repeated 30 min and 3 h after rectal anesthetization. RESULTS: Rectal pressure was significantly reduced at 45 degrees and 40 degrees C, showed no change at 37 degrees or 30 degrees C, and was increased at 20 degrees, 10 degrees, and 0 degrees C. At 45 degrees C patients felt rectal pain but no sensation of warmth; at 40 degrees, 37 degrees, and 30 degrees C neither rectal pain nor warm sensation was felt; at 20 degrees C or below rectal pain and cold sensation were perceived. Rectal balloon filling 30 min after anesthetization caused no significant rectal pressure changes or sensation of coldness or warmth; after 3 h, when the anesthetic had waned, the rectal pressure response and sensation were similar to those before anesthetization. CONCLUSIONS: Warm saline appears to cause rectal relaxation and cold saline rectal contraction. Subjects did not perceive sensation of warmth in the rectum but felt cold sensation, which may indicate the presence of cold receptors in the rectal wall. The rectal response to temperature variations is suggested to be reflex in nature as evidenced by its absence on rectal anesthetization. Such reflex, designated "thermorectal reflex," is proposed to mediate the rectal response and is speculated to have clinical significance in rectal dysfunctional and neurogenic disorders.