Decoding the role of miRNAs in multiple myeloma pathogenesis: A focus on signaling pathways.

Multiple myeloma (MM) is a cancer of plasma cells that has been extensively studied in recent years, with researchers increasingly focusing on the role of microRNAs (miRNAs) in regulating gene expression in MM. Several non-coding RNAs have been demonstrated to regulate MM pathogenesis signaling pathways. These pathways might regulate MM development, apoptosis, progression, and therapeutic outcomes. They are Wnt/ß-catenin, PI3K/Akt/mTOR, P53 and KRAS. This review highlights the impending role of miRNAs in MM signaling and their relationship with MM therapeutic interventions.

Polarity Based Model for Guiding Medical School Strategy During Crisis - A Cross Sectional Qualitative Study.

BACKGROUND: Crises in academia can best be dealt with as a polarity that needs to be leveraged rather than a problem that needs to be solved. This work aimed at utilizing the Polarity Approach for Continuity and Transformation (PACT)™ to establish a guide for medical schools during times of crisis to minimize the effect of crisis-driven decisions on strategic growth. SUBJECTS AND METHODS: A qualitative study following the 5-Steps of the PACT process was conducted. A virtual mapping session was held with 108 medical educators from 22 countries to determine the upsides and downsides of strategic orientation and crisis management subsequently. RESULTS: Four polarity maps were generated identifying four tension areas; University reputation, mission, teams, and individuals followed by a 72-item assessment and another mapping session to map the warning signs and action steps. A comparison between private school scores and the whole cohort of respondents showed that private schools had the least problems in team-oriented work. CONCLUSION: This study highlighted the importance of taking measures to communicate the mission and supporting team functions inside universities either by enhancing resources or utilizing time and effort-saving strategies.

Measuring Students' Perceptions of Educational Environment in the PBL Program of Sharjah Medical College.

BACKGROUND: Students' perception of their educational environment has a significant impact on their behavior and academic progress. The recent worldwide usage of innovative problem-based learning (PBL) medical programs requires major changes in medical schools and their environments. Therefore, measuring students' perceptions of the complex PBL environment has become a critical necessity as a determinant of students' academic success and as a part of attaining the quality standards of education. Ours being a new medical college employing the PBL curriculum, it was important to measure the students' perception of the educational environment in order to identify the strengths and weaknesses of the curriculum and to plan for any future improvements. AIM AND OBJECTIVES: The aim of this study was to evaluate students' perceptions in the preclinical phase of the PBL educational environment in the College of Medicine, Sharjah Medical College, United Arab Emirates, and to recommend remedial procedures. MATERIAL AND METHODS: In this cross-sectional study, the English version of the Dundee Ready Education Environment Measure (DREEM) inventory was submitted to 250 students in years 1, 2, and 3. The data were analyzed using the SPSS 20 software, and significance was taken at P ≤ 0.05. The survey was performed in a mid-semester week, ie, in March 2014. No ethical issues were encountered during the process of this study. RESULTS: Two-hundred and fifty students responded to the questionnaire (100% response rate). The overall DREEM score was 113.4/200 (56.7%). First-year students expressed higher overall significant level of perception (119.4/200) than second-year (107.4/200) and third-year (112.7/200) students. In addition, first-year students perceived their learning, teaching, and academic climates as more significant than the other two batches. The scores obtained in the five domains were as follows; 28/48 in perception of learning, 26/44 in perception of teaching, 18/32 in academic self-perceptions, 27/48 in perceptions of atmosphere, and 15/28 in social self-perceptions. First-year students achieved the highest score (18.7/32) in the academic self-perception, and second-year students achieved the lowest (16.5/32). The total score was significantly higher in female students than in male students (115.9 vs 108.1). CONCLUSIONS: The present study revealed that the PBL environment is generally perceived positively by our medical students. Female students exhibited higher perception than male students. Nevertheless, areas such as curriculum overload and inadequate student support still require further fine-tuning and remedial measures.

Antioxidant effect of garlic (Allium sativum) and black seeds (Nigella sativa) in healthy postmenopausal women.

OBJECTIVES: The objective of this study is to investigate the antioxidant effects of garlic extract and crude black seeds' consumption on blood oxidant/antioxidant levels in healthy postmenopausal women. METHODS: In total, 30 healthy postmenopausal women (mean age = 50.31 ± 4.23 years) participated. They ingested two garlic soft gels per day (each is equivalent to 1000 mg of fresh garlic bulb) and crude black seed grounded to powder in a dose of 3 g/day for 8 weeks. Oxidant (malondialdehyde) activity in plasma and antioxidants superoxide dismutase and glutathione peroxidase activities in erythrocytes were studied. RESULTS: Significant low levels of plasma malondialdehyde with increased erythrocyte glutathione peroxidase and superoxide dismutase activities. DISCUSSION: Menopause is associated with an increase in oxidative stress and a decrease in some antioxidant parameters. Consumption of garlic extracts and crude black seeds may have a beneficial effect on improved balance between blood oxidants and antioxidants in healthy postmenopausal women.

Interstitial cells of Cajal, the Maestro in health and disease.

Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very significant physiological role orchestrating the normal peristaltic activity of the digestive system. They are the pacemaker cells in gastrointestinal (GI) muscles. Absence, reduction in number or altered integrity of the ICC network may have a dramatic effect on GI system motility. More understanding of ICC physiology will foster advances in physiology of gut motility which will help in a future breakthrough in the pharmacological interventions to restore normal motor function of GI tract. This mini review describes what is known about the physiologic function and role of ICCs in GI system motility and in a variety of GI system motility disorders.

Functional activity of the rectum: A conduit organ or a storage organ or both?

AIM: To investigate whether the degree of rectal distension could define the rectum functions as a conduit or reservoir. METHODS: Response of the rectal and anal pressure to 2 types of rectal balloon distension, rapid voluminous and slow gradual distention, was recorded in 21 healthy volunteers (12 men, 9 women, age 41.7 +/- 10.6 years). The test was repeated with sphincteric squeeze on urgent sensation. RESULTS: Rapid voluminous rectal distension resulted in a significant rectal pressure increase (P < 0.001), an anal pressure decline (P < 0.05) and balloon expulsion. The subjects felt urgent sensation but did not feel the 1st rectal sensation. On urgent sensation, anal squeeze caused a significant rectal pressure decrease (P < 0.001) and urgency disappearance. Slow incremental rectal filling drew a rectometrogram with a "tone" limb representing a gradual rectal pressure increase during rectal filling, and an "evacuation limb" representing a sharp pressure increase during balloon expulsion. The curve recorded both the 1st rectal sensation and the urgent sensation. CONCLUSION: The rectum has apparently two functions: transportation (conduit) and storage, both depending on the degree of rectal filling. If the fecal material received by the rectum is small, it is stored in the rectum until a big volume is reached that can affect a degree of rectal distension sufficient to initiate the defecation reflex. Large volume rectal distension evokes directly the rectoanal inhibitory reflex with a resulting defecation.

Role of the rectosigmoidal junction in fecal continence: concept of the primary continent mechanism.

HYPOTHESIS: At mass contraction of the descending colon, the colonic contents stop at the sigmoid colon (SC) and do not pass directly to the rectum. We investigated the hypothesis that a continent mechanism seems to exist at the rectosigmoidal junction (RSJ), preventing the direct passage of stools from the descending colon to the rectum. METHODS: The SC in 16 healthy volunteers (mean +/- SD age, 38.6 +/- 10.2 years; 9 men and 7 women) was distended with an isotonic sodium chloride solution-filled balloon, and the pressure response of the RSJ and the rectum was recorded at rapid and gradual filling of the balloon. The test was repeated after the SC and RSJ were anesthetized separately. RESULTS: Rapid SC balloon distension with a mean +/- SD of 52.1 +/- 3.6 mL of isotonic sodium chloride solution effected an RSJ pressure increase to a mean +/- SD of 67.8 +/- 18.4 cm H(2)O (P<.01) with no rectal pressure response (P>.05). Slow SC filling produced a progressive increase in RSJ pressure but no rectal pressure change. At a mean +/- SD SC distending volume of 86.3 +/- 4.1 mL, the RSJ pressure decreased to 9.6 +/- 2.8 (P<.01), and the balloon was dispelled to the rectum; rectal pressure increased (P<.001), and the balloon was expelled to the exterior. The RSJ pressure did not respond to distension of the anesthetized SC. CONCLUSIONS: Contraction of the RSJ at rapid SC distension with big volumes implies a reflex relationship that we call the RSJ guarding reflex. This reflex seems to prevent the descending colon contents from passing directly to the rectum. It is considered the first continent reflex and may serve as an investigative tool in the study of fecal incontinence.

The effect of esophageal and gastric distension on the crural diaphragm.

BACKGROUND: The mechanism of prevention of gastric reflux into the esophagus is not exactly known. The lower esophagus has a barrier function provided by the lower esophageal sphincter. We investigated the hypothesis that the crural diaphragm shares in the barrier function not only mechanically but also actively through a crural-esophageal-gastric reflex action. METHODS: The study was performed during repair of abdominal ventral and incisional hernias in 20 subjects (11 men, 9 women; age 38.6+/-4.8 years). The electromyographic response of the crural diaphragm to individual balloon distension of esophagus and stomach was recorded by means of a needle electrode inserted into the crural diaphragm and connected to an electromyographic apparatus. The recordings were repeated after separate crural, esophageal, and gastric anesthetization. RESULTS: The crural diaphragm exhibited basal motor unit action potentials, which decreased on esophageal distension (P<0.001) after a mean latency of 17.3+/-2.8 SD ms. The crural diaphragm response to esophageal distension did not occur after the crural diaphragm or esophagus was anesthetized. Gastric distension effected an increase of crural diaphragm electromyographic activity with a mean latency of 18.4+/-4.6 ms; this effect could not be achieved after the crural diaphragm or stomach was anesthetized. CONCLUSIONS: The crural diaphragm has a resting tone that relaxes after esophageal distension and contracts after gastric distension. This sphincter-like action of the crural diaphragm appears to be a reflex and is mediated through the esophagocrural inhibitory and gastrocrural excitatory reflexes. The crural diaphragm seems to share actively in the gastroesophageal competence mechanism.

Effect of straining on diaphragmatic crura with identification of the straining-crural reflex. The "reflex theory" in gastroesophageal competence.

BACKGROUND: The role of the crural diaphragm during increased intra-abdominal pressure is not exactly known. We investigated the hypothesis that the crural diaphragm undergoes reflex phasic contraction on elevation of the intra-abdominal pressure with a resulting increase of the lower esophageal pressure and prevention of gastro-esophageal reflux. METHODS: The esophageal pressure and crural diaphragm electromyographic responses to straining were recorded in 16 subjects (10 men, 6 women, age 36.6 +/- 11.2 SD years) during abdominal hernia repair. The electromyogram of crural diaphragm was recorded by needle electrode inserted into the crural diaphragm, and the lower esophageal pressure by a saline-perfused catheter. The study was repeated after crural anesthetization and after crural infiltration with saline. RESULTS: The crural diaphragm exhibited resting electromyographic activity which showed a significant increase on sudden (coughing, p < 0.001) or slow sustained (p < 0.01) straining with a mean latency of 29.6 +/- 4.7 and 31.4 +/- 4.5 ms, respectively. Straining led to elevation of the lower esophageal pressure which was coupled with the increased electromyographic activity of the crural diaphragm. The crural response to straining did not occur during crural diaphragm anesthetization, while was not affected by saline infiltration. The lower esophageal pressure declined on crural diaphragm anesthetization. CONCLUSIONS: Straining effected an increase of the electromyographic activity of the crural diaphragm and of the lower esophageal pressure. This effect is suggested to be reflex in nature and to be mediated through the "straining-crural reflex". The crural diaphragm seems to play a role in the lower esophageal competence mechanism. Further studies are required to assess the clinical significance of the current results in gastro-esophageal reflux disease and hiatus hernia.

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.

Vesical pacing in patients with overactive bladder: technique and results.

OBJECTIVES: A recent study has demonstrated that the electric activity of the overactive bladder (OAB) is 'dysrhythmic'. The cause was attributed to a disordered vesical pacemaker which discharges these waves. In a subsequent study, the dysrhythmic waves have been 'normalized' by vesical pacing and the optimal parameters which are required to achieve normalization have been defined. We investigated the hypothesis that vesical pacing of the OAB might improve not only the vesical electric activity but also the symptoms. METHODS: Vesical pacing was used in 9 patients (age 39.2 +/- 10.3; 5 women, 4 men) with OAB. Under anesthesia, the pacemaker was implanted in an inguinal subcutaneous pocket and connected to 2 pacing electrodes implanted into the vesical vault. The normalization of the waves was tested by 2 recording electrodes which were temporarily applied to the vesical wall and removed post-testing. The pacemaker was then programmed for home pacing to be activated at given times. RESULTS: Vesical pacing effected normalization of the dysrhythmic electric waves with disappearance of the OAB symptoms in 7 patients and failed in 2. Vesical pacing was abandoned in 3/7 patients after a few months following the spontaneous disappearance of the symptoms. CONCLUSIONS: Vesical pacing has normalized the dysrhythmic electric activity and suppressed the symptoms of the OAB in 77.7% of patients. The pacemaker was removed in 5 patients: 2 failures and 3 after spontaneous waves normalization. No complications were encountered. Vesical pacing is suggested as a treatment for OAB when commonly used therapeutic modalities have failed.

Does the crural diaphragm share in the contractile activity of the costal diaphragm? The concept of an "autonomous esophageal crus" and its role in esophageal competence.

BACKGROUND: We investigated the hypothesis that the esophageal crus (EC, part of the crus surrounding the esophagus) is an "individual muscle" and does not share in the contractile activity of the costal diaphragm (CD). MATERIAL/METHODS: The electric activities of the EC and the costal diaphragm (CD) were recorded in 21 subjects (12 men, 9 women, aged 41.6+/-10.4 years) scheduled for laparotomy. One needle electrode was introduced into the EC, one into each vertebral crus (VC), and one in the CD. Recording was performed before and after diaphragmatic paralysis by curarization. While the diaphragm was paralyzed, the responses of the EC and the 2 VCs to CD stimulation were registered. RESULTS: The CD had significantly higher resting motor unit action potentials (MUAPs) than the EC and the 2 VCs (p<0.05), and the EC higher MUAPs than the 2 VCs (p<0.05). During diaphragmatic contraction on inspiration or by stimulation (5 square pulses, 1 ms apart, threshold 32.2+/-6.3 mA), the MUAPs of the CD increased significantly (p<0.01), while those of the EC or VCs exhibited no significant change (p<0.05). CONCLUSIONS: The current findings suggest that the EC is an autonomous muscle which does not share in the contractile activity of the CD. The EC seems to be essentially involved in the competent mechanism of the lower esophagus and has no role in respiratory function.

The electrovaginogram: study of the vaginal electric activity and its role in the sexual act and disorders.

OBJECTIVES: We investigated the hypothesis that the vagina generates electric waves which effect vaginal contraction during penile thrusting. METHODS: In 24 healthy female volunteers, the electric waves of the vagina were recorded by two electrodes applied to its wall. The vaginal pressure was registered by a manometric tube. The electric waves and vaginal pressure were recorded at rest and on vaginal distension by condom in increments of 10 ml of carbon dioxide. The test was repeated after vaginal anesthetization proximally and distally to the electrodes. RESULTS: Slow waves (SWs) were recorded from the two electrodes with regular rhythm and similar frequency, amplitude and conduction velocity. They were randomly followed or superimposed by action potentials (APs). Vaginal pressure increase was coupled with APs. Large-volume condom distension significantly increased the electric waves' variables and pressure. Upon vaginal anesthetization, the electric waves were recorded proximal but not distal to the anesthetized area. CONCLUSIONS: Electric waves could be recorded from the vagina. They spread caudad. A pacemaker was postulated to exist at the upper vagina evoking these waves. The electric waves seem to be responsible for the vaginal contractile activity. Large-volume vaginal distension effected an increase in the vaginal electric waves and pressure which probably denotes increased vaginal muscle contraction. It appears that penile thrusting during coitus stimulates the vaginal pacemaker which effects an increase in vaginal electric activity and muscle contractility and thus leading to an increase in sexual arousal. The vaginal pacemaker seems to represent the G spot, which is claimed to be a small area of erotic sensitivity in the vagina. The electrovaginogram may act as a diagnostic tool in the investigation of sexual disorders.

Vesical pacing: pacing parameters required for normalization of vesical electric activity in patients with overactive bladder.

There are several modalities for the treatment of the overactive bladder (OAB), but the results may not be satisfactory. A recent study has demonstrated that the OAB has a dysrhythmic electric activity that seems to result from a disordered vesical pacemaker. We hypothesized that vesical pacing may correct the irregularities of the vesical electric waves and consequently normalize the vesical contractility. In this communication, we primarily defined the adequate pacing parameters required for correction of the vesical dysrhythmia. 36 patients with OAB were divided into a study group (22; 13 women; mean age 40.2 years) and a control group (14; 8 women; mean age 41.8 years). Ten healthy volunteers (6 women; mean age 39.8 years) were included in the study. Three 28-gauge cardiac pacing electrodes were hooked to the vesical mucosa: one (pacing) to the vault, and two (recording) to the lateral wall. Electric activity at rest and during stimulation of the pacing electrode was recorded in the study group and the healthy volunteers. In the control group, recording was done without pacing. Reproducible regular triphasic SWs were recorded from the 2 electrodes of the healthy volunteers with a similar pattern from the 2 electrodes of each individual subject. The optimal pacing parameters we determined were: an amplitude of 5 mA, a pulse width of 200 ms and a frequency of 20% higher than the frequency of the basal vesical waves. Vesical pacing effected a significant increase of waves' variables. The OAB patients exhibited a "dysrhythmic" wave pattern which was normalized during vesical pacing using the aforementioned pacing parameters. The optimal parameters required for vesical pacing of the dysrhythmic waves of the OAB were determined and succeeded in normalization of the vesical electric activity. Vesical pacing is suggested to be used as a therapeutic tool for the treatment of the OAB.

Electric activity of the colon in subjects with constipation due to total colonic inertia: an electrophysiologic study.

BACKGROUND: Idiopathic constipation may result from colonic inertia, which affects the whole colon or is localized to an area of the colon. The colon exhibits electric activity in the form of slow waves or pacesetter potentials (PPs) and action potentials (APs), which are coupled with elevated colonic pressure. The APs are claimed to be responsible for colonic motor activity. HYPOTHESIS: Colonic electric activity is disordered in patients with constipation due to colonic inertia. METHODS: Electric activity was studied in 11 patients with colonic inertia and constipation (mean +/- SD age, 42.8 +/- 6.6 years; 7 women) who underwent total colectomy. Eight volunteers who had no gastrointestinal complaints (mean +/- SD age, 40.6 +/- 5.8 years; 5 women) acted as controls. Control subjects underwent laparotomy for hernia repair (n = 7 patients) and for removal of a mesenteric cyst (n = 1 patient). During the operation, 2 monopolar silver-silver chloride electrodes were applied to the cecum and the ascending, transverse, descending, and sigmoid colon. RESULTS: Electric waves (PPs and APs) were recorded from all parts of the colon in control subjects. The waves were monophasic, negatively deflected, and had regular rhythm. The wave variables from the 2 electrodes of each segment of the colon were identical and reproducible. They progressively increased aborally. In the colonic inertia group, 5 patients had recorded waves from the cecum and ascending colon but no waves from the rest of the colon. The wave variables were significantly lower than those of the controls (P =.02). In the remaining 6 patients, no waves were registered from the whole colon. CONCLUSIONS: Regular electric waves were recorded from the colons of control subjects. The aboral increase of their frequency, amplitude, and conduction velocity suggests that colonic motile activity increases analward, reaching its maximum in the sigmoid colon to expel its solid contents. We postulate that constipation in patients with colonic inertia is attributable to weak or absent electric activity, the cause of which is unknown. A disorder of the interstitial cells of Cajal, which generate electric activity, is suggested to have a role in inducing diminished or absent colonic motor activity, a point that should be investigated.

Role of the rectosigmoid pacemaker and electric activity in rectal motility: mechanism and clinical significance.

BACKGROUND: The rectum exhibits electric activity in the form of slow waves or pacesetter potentials (PPs) and action potentials (APs), which are suggested to be initiated from a rectosigmoid pacemaker (RSP). We hypothesized that the RSP and electric waves are responsible for rectal motility. This hypothesis was investigated. METHODS: The rectum of 13 mongrel dogs was exposed through an abdominal incision, and 3 electrodes were fixed serially to the rectal serosa. The rectal pressure was measured by a 6 F saline-perfused catheter and the rectal electromechanical response to rectal balloon distension in increments of 5 ml of air was registered. The test was repeated after rectosigmoid junction (RSJ) anesthetization by 20 minutes and 3 hours using xylocaine injection. It was done also after saline instead of xylocaine injection. RESULTS: PPs and APs were recorded and had the same frequency, amplitude and conduction velocity from the 3 electrodes of the same animal. APs occurred randomly and were coupled with elevated rectal pressure. Rectal balloon distension produced increase of the rectal electric activity and pressure, which increased with the increase of the rectal distension until, at a mean volume of 31.2 +/- 5.4 ml, the balloon was expelled to the exterior. RSJ anesthetization abolished the rectal electric waves and effected no balloon expulsion with high volume rectal distension. The rectal waves appeared after waning of the anesthetic effect. Saline injection into the RSJ produced no significant effect on the rectal electromechanical activity. CONCLUSION: Rectal electric waves are suggested to be initiated from the RSP and to be responsible for the rectal motor activity. Incremental rectal balloon distension effected progressive increase of the rectal electromechanical activity until the balloon was expelled to the exterior RSJ anesthetization blocked the electric waves and the electromechanical response to rectal distension. These results have probably clinical significance when performing electrorectograms for various rectal pathologic conditions as well as when applying an artificial pacemaker to the non-contractile rectum.

Effects of exposure to extremely low-frequency magnetic field of 2 G intensity on memory and corticosterone level in rats.

In the present study, we examined the effects of chronic exposure (1 and 2 weeks) to an extremely low-frequency magnetic field (ELFMF) of 2 G intensity on memory in rats using an object recognition task. Comparable groups of rats were exposed for 1, 2 or 4 weeks to ELFMF and the following day blood samples were collected from each rat for the measurement of corticosterone level. Our results demonstrate that exposure to ELFMF induces a significant increase in the level of corticosterone in blood plasma and is associated with impairment in discrimination between familiar and novel objects.

Electrophysiological study of the rectosigmoid canal: evidence of a rectosigmoid sphincter.

Previous studies strongly suggest the presence of a sphincter at the rectosigmoid junction, an area with a mean length of 2.8 cm in adults, called the rectosigmoid canal (RSC). To find supporting evidence of a sphincteric function for the RSC, two recording electrodes were applied to each of the sigmoid colon (SC), RSC and rectum (R) in 11 subjects during operative repair of huge incisional hernias. The RSC, SC and R were individually stimulated by a further electrode and their pressures monitored by a three-channel microtip catheter. The variables of the slow waves or pacesetter potentials, recorded at rest from the RSC and R, were significantly higher than those of the SC. While the frequency and conduction velocity of pacesetter potentials of the RSC and R were similar, the potential pacesetter amplitude of the RSC was significantly higher. The increase of the electrical activity and pressure upon electrostimulation was significantly greater in the RSC than that of the SC or R. Electrostimulation led to an increase in pressure of all three areas, the RSC increase being significantly the greatest. The greater increase of the electrical activity and pressure of the rectosigmoid canal upon electrostimulation, compared to that of the SC or R, strongly supports the presence of a rectosigmoid sphincter.