Electrophysiologic identification of the location of the colonic pacemakers in humans: further study.

We recently defined the sites of four colonic pacemakers that appear to generate the electric waves assumed to be responsible for the colonic motility. We hypothesized that a dysfunction of one or more of these pacemakers might interfere with the generation of electric waves and the colonic motility. This hypothesis was investigated in the current communication. The tests were performed during the repair of huge incisional hernia of 8 subjects (5 F, 3 M; mean age 42.8 +/- 3.3 SD years). Two electrodes were applied to each of the terminal ileum (TI), cecum (C), and ascending (AC), transverse (TC), descending (DC), and sigmoid (SC) colon. The electric activity of the TI and the various colonic segments was recorded using surface silver-silver chloride electrodes applied to the colon. The site of change of the wave variables between the TI and the C and between the different other colonic segments was determined by changing the position of the electrodes placed over the segments to be examined. Presumably, the sites where the wave variables changed represent the potential location of the pacemakers. We anesthetized these sites individually by injection of 2% Xylocaine, and then recorded the electric activity after 20 min in all the subjects and after 2 h in only 5 subjects. Electric waves in the form of pacesetter and action potentials were recorded from the TI and the colon. The sites of potential pacemakers could be defined at the ileocecal and cecocolonic junctions, at the mid third of the TC, and at the colosigmoid junction. Anesthetization of the cecal pole resulted in disappearance of the cecal electric waves, with persistence of the waves from the other colon segments. Anesthetization of the cecocolonic junction eliminated the electric waves of the AC and the right half of the TC, while the waves in the rest of the colon persisted. The remaining two pacemaker sites produced similar results when anesthetized. The electric waves reappeared after the anesthetic effect had waned. Thus, the colon possesses at least four pacemakers that appear to mediate the colonic motor activity. Individual pacemaker block by anesthetization effected disappearance of electric waves in the relative colonic segment, which reappeared after waning of the anesthetic effect. The disappearance of these waves upon pacemaker anesthetization supports a relationship between the pacemakers at the anesthetized site and the electric waves. The electric waves seem to be generated by these pacemakers. We suggest that colonic inertia, segmental or total, results from the dysfunction of one or more pacemakers, and that an artificial pacemaker could be applied for the treatment of such conditions. These suggestions need to be further studied.     

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.     

Effect of rectal distension on rectal electromechanical activity.

The rectum possesses electric activity in the form of pacesetter potentials (PPs) and action potentials (APs). The latter are associated with rectal pressure elevation and share in the rectal motile activity. A recent study has shown that electric waves are transmitted by the longitudinal but not the circular rectal muscle fibers. Rectal motile activity under normal physiologic conditions was suggested to be induced by the electric waves, that effect longitudinal muscle contraction, as well as by circular muscle stretch resulting from rectal distension. The current study investigated the effect of rectal overdistension on the rectal electromechanical activity aiming at assessing the effect of stool accumulation in the rectum on rectal motile activity. Under general anesthesia, the abdomen of 16 mongrel dogs was opened, the rectum exposed, and 3 electrodes were sutured to the rectal serosa. The rectal pressure was measured by a 10-F catheter connected to a pressure transducer. Rectal distension was achieved by a balloon inflated with carbon dioxide (CO2). Simultaneous recording of the electric activity and rectal pressure was performed during rectal inflation in increments of 10 mL CO2. There was significant increase of rectal pressure as well as of frequency, amplitude, and conduction velocity of PPs and APs on rectal distension. The more the rectal balloon was distended, the more was the increase in rectal pressure and waves variables; the increase was maximal just before balloon expulsion at 40 mL distension. Upon rectal overdistension (50 and 60 mL), no PPs or APs were recorded and the rectal pressure was 0; no balloon expulsion occurred. Rectal overdistension (pathologic distension) appears to abort the electromechanical activity of the rectum and lead to failure of the rectum to expel the balloon. This effect is suggested to be due to overstretch of rectal musculature with a resulting loss of the rectal electric waves and noncontraction of the muscle fibers. These findings appear to explain the cause of rectal atony, which occurs in rectal inertia and leads to constipation.     

On the mechanism of colonic motility: the electric activation theory of colonic contraction

PURPOSE: A previous study has demonstrated that the longitudinal muscle possesses electric activity, while the circular does not (A. Shafik and A. A. Shafik, 2000, Front. Biosci. 5, b5). In the current study, we investigated the mechanism of action of the two colonic muscle coats in the motility of the gut. METHODS: Fourteen patients (43.8 years, 10 men) with left colon or rectal cancer were scheduled to have transverse colostomy as a part of their operation. The electric activity of the ascending colon was recorded by three electrodes applied to each of the circular and the longitudinal (taenia coli) muscle coats. Simultaneously, the colonic pressure was recorded before and after colonic distension. The test was repeated after longitudinal muscle anesthetization. RESULTS: Electric waves in the form of pacesetter (PPs) and action (APs) potentials were recorded from the longitudinal but not the circular muscle fibers. APs were associated with an intracolonic pressure rise. Colonic distension produced significant increase in the PPs and APs recorded from the longitudinal muscle with appearance of similar electric activity from the circular muscle. Electric activity and colonic pressure increased upon increase in the colonic distension until the balloon in the proximal part of the ascending colon moved to the transverse colon in one mass contraction. Ten minutes after longitudinal muscle anesthetization, no electric activity was recorded from the longitudinal and circular muscles upon colonic distension. CONCLUSIONS: The electric waves appear to be transmitted from the longitudinal to the circular muscle upon colonic distension. The giant migrating contractions of the colon that move the food bolus from the cecum to the transverse colon are suggested to be a function of the longitudinal muscle electric activation with gut lumen modulation by the circular fibers.     

Electric waves recorded from the testicle: are they capsular or from the testicular tissue?

We demonstrated in a previous study that electric waves could be recorded from the testicle by applying the electrodes either directly to the tunica albuginea (TA) or transcutaneously. As the TA contains smooth muscle fibres which presumably transmit the electric waves, we investigated the hypothesis that the electric waves recorded from the testicle originated from the TA. During the repair of inguino-scrotal hernia in 24 men [age 36.6 +/- 8.6 years (mean +/- SD)], the tunica vaginalis was everted because of the presence of hydrocele. The electric activity of the TA was recorded by three surface electrodes and that of the testicle by three needle electrodes. The recorded potentials were amplified and displayed on an electromyographic apparatus. Triphasic slow waves (SWs) were recorded from the TA. They showed similar frequency, amplitude and conduction velocity from the three electrodes of the individual subject and were reproducible. They were followed or superimposed by bursts of action potentials (APs) which occurred randomly. No waves were recorded from the three needle electrodes inserted into the testicular tissue. The current study could demonstrate that the electric waves recorded from the electrodes applied to the testicle were derived from the TA and not from the testicular tissue. This finding apparently denotes that the TA has a resting tone and probably motile activity, the role of which in testicular function needs to be studied.     

Role of the Enteric Nervous Plexus in Rectal Motile Activity: An Experimental Study

The gut innervation is formed by an intrinsic and an extrinsic component. The former is responsible for the intestinal contractions that occur in the total absence of extrinsic innervation. We hypothesize that the intrinsic plexuses do not produce local contraction, but mediate reflex actions of the gut musculature. This hypothesis was investigated in the rectum of the experimental animal. In 16 anesthetized mongrel dogs, the rectum was exposed, and 3 monopolar silver-silver chloride electrodes were sutured serially to the rectal wall and connected to a rectilinear pen recorder. The rectal electric activity was recorded at rest and on rectal inflation while the anal pressure was synchronously registered. The tests were repeated after separate drug administration using phentolamine, propranolol (adrenoceptor blocking agents), atropine (cholinergic blocking agent), drotaverine (direct smooth muscle relaxant), and nitroglycerine. (NO donor, inhibitory noncholinergic, nonadrenergic mediator). Slow waves or pacesetter potentials (PPs) and action potentials (APs) were recorded from the three electrodes. Rectal balloon distension caused an increase of frequency, amplitude, and conduction velocity of these waves, as well as a decrease of anal pressure. Repetition of the test after administration of phentolamine, propranotol, and atropine effected no change in rectal electromyelographic (EMG) activity or anal pressure, while drotaverine and nitroglycerine administration aborted both the electric activity and the anal pressure response. We conclude that the rectal electric activity, presumably responsible for rectal motility, was not aborted by enteric nervous plexus block but by direct muscle relaxant. This suggests that the enteric plexus has no direct action on the rectal motile activity but mediates the rectal reflex actions. This concept might explain some of the hitherto unknown mechanisms of rectal dyssynergia syndromes.     

Role of the enteric nervous plexus in rectal motile activity: an experimental study.

The gut innervation is formed by an intrinsic and an extrinsic component. The former is responsible for the intestinal contractions that occur in the total absence of extrinsic innervation. We hypothesize that the intrinsic plexuses do not produce local contraction, but mediate reflex actions of the gut musculature. This hypothesis was investigated in the rectum of the experimental animal. In 16 anesthetized mongrel dogs, the rectum was exposed, and 3 monopolar silver-silver chloride electrodes were sutured serially to the rectal wall and connected to a rectilinear pen recorder. The rectal electric activity was recorded at rest and on rectal inflation while the anal pressure was synchronously registered. The tests were repeated after separate drug administration using phentolamine, propranolol (adrenoceptor blocking agents), atropine (cholinergic blocking agent), drotaverine (direct smooth muscle relaxant), and nitroglycerine. (NO donor, inhibitory noncholinergic, nonadrenergic mediator). Slow waves or pacesetter potentials (PPs) and action potentials (APs) were recorded from the three electrodes. Rectal balloon distension caused an increase of frequency, amplitude, and conduction velocity of these waves, as well as a decrease of anal pressure. Repetition of the test after administration of phentolamine, propranotol, and atropine effected no change in rectal electromyelographic (EMG) activity or anal pressure, while drotaverine and nitroglycerine administration aborted both the electric activity and the anal pressure response. We conclude that the rectal electric activity, presumably responsible for rectal motility, was not aborted by enteric nervous plexus block but by direct muscle relaxant. This suggests that the enteric plexus has no direct action on the rectal motile activity but mediates the rectal reflex actions. This concept might explain some of the hitherto unknown mechanisms of rectal dyssynergia syndromes.     

Transcutaneous electrocavernosography: a tool for recording the electromyographic activity of the corpora cavernosa

PURPOSE: The electric activity of the corpora cavernosa (CC) is recorded by needle electrodes introduced into the CC. We investigated the hypothesis that transcutaneous electrocavernosography (ECG) would register electric waves similar to those recorded by the needle ECG but noninvasively. MATERIALS AND METHODS: The ECG was recorded transcutaneously in 35 healthy volunteers (mean age 37.6 +/- 4.8 SD years). Two silver-silver chloride electrodes were applied on the dorsum of the penis over 1 of the CC. A reference electrode was applied to the thigh. Intracavernosal ECG using 2 needle electrodes introduced into the CC was performed in the same subjects. At least two 20 minutes sessions were recorded for each subject. RESULTS: Slow waves (SWs) were registered transcutaneously. The waves from the 2 electrodes in each individual had the same frequency, amplitude and conduction velocity. They had a regular rhythm and were reproducible. The SWs were followed or superimposed by action potentials which occurred randomly. The transcutaneously recorded SWs were confirmed by the intracavernous route. Both routes had similar ECG recordings. CONCLUSIONS: The study demonstrated that the transcutaneous ECG recorded electric waves similar to those registered by the intracavernosal route. The transcutaneous ECG is simple, easy, non-invasive, and may be included as an investigative tool in the diagnosis of erectile dysfunction.     

Electrocavernosogram in erectile dysfunction: a diagnostic tool

Corpora cavernosa (CC) evoke electric waves that appear to be of diagnostic significance in evaluation of erectile dysfunction (ED). We investigated the hypothesis that electrocavernosography (ECG) exhibits different patterns in the various types of ED: neurogenic, vasculogenic, and psychogenic. Electrocavernosography was performed in the flaccid phase in 16 neurogenic, 28 vasculogenic (15 arteriogenic, 13 venogenic), and 24 psychogenic patients with ED, and in 15 healthy volunteers (controls). Two needle electrodes were introduced into the CC and the EMG activity was recorded in each of the 2 CCs of the same subject. Two 20 minute recording sessions were performed for each subject. The controls recorded slow waves (SWs) with regular rhythm and identical frequency, amplitude and conduction velocity from the 2 electrodes of the same subject. Random action potentials (APs) were superimposed on or followed the SWs. The ECG in the neurogenic ED recorded no waves in 14/16 patients and occasional irregular waves in 2. The SWs of the arteriogenic ED had irregular rhythm and variable and low parameters compared to those of the controls. The ECG of the patients with venogenic ED was similar to that of the controls, while the ECG of the psychogenic ED exhibited SWs with irregular rhythm and higher parameters than the controls. The study has revealed various ECG patterns in ED: "silent" in neurogenic. "bradyarrhythmic" in arteriogenic, "normal" in venogenic, and "overactive" in psychogenic ED. We suggest that electrocavernosography has the potential to function as an investigative tool in diagnosing the type of ED provided further studies are performed to verify the described findings.     

Electrovasogram in patients with obstructive azoospermia and absent vas deferens

Summary The electric activity of the vas deferens (electrovasogram, EVG) was studied in 22 patients with obstructive azoospermia (OA), in 9 patients with bilaterally absent vasa deferentia, in 10 patients who had undergone epididymovasostomy for OA, and in 12 healthy volunteers (controls). Two electrodes were applied to the posterior aspect of the upper scrotum. EVG in normal subjects showed pacesetter potentials (PPs) that had the same frequency, amplitude, and velocity of conduction from both electrodes and were consistent in the individual subject on all test days. The PPs were followed randomly by action potentials (APs). The EVG in OA exhibited bradyvasa, i.e., diminished PP frequency, amplitude, and velocity, in 14 patients and a silent EVG in 8. Eight of the ten patients in whom azoospermia persisted after epididymovasostomy had a silent EVG. The remaining two patients, whose semen character had normalized after epididymovasostomy, revealed a normal EVG. A silent EVG was recorded for the nine patients with absent vasa deferentia. The electric activity is believed to be responsible for vasal motility. The bradyvasa or silent EVG encountered in OA might be attributable to the arrested function of the vas deferens and resultant vasal inertia. The latter may persist after epididymovasostomy and be responsible for the failure of the semen to normalize, as occurred in eight patients. In conclusion, EVG is a simple, easy, noninvasive, and nonradiologic technique that might be used as a diagnostic tool in the investigation of vas deferens disorders and infertility.     

Electrourethrogram: Study of the electric activity of the urethra and its clinical significance

Purpose: Apart from the urethral sphincters, the electric activity of the urethra has not been fully addressed in the literature. We investigated the hypothesis that also the non-sphincteric part of the urethra possesses electric activity which may have clinical significance.Materials and methods: Urethral electric activity was studied in 24 healthy volunteers (mean age 40.6 ±: 13.6 years, 14 women). Two electrodes in women and three in men were applied to the urethral mucosa distal to the striated urethral sphincter. A manometric catheter was placed into the penile urethra in men and distal to the striated sphincter in women.Results: Monophasic negatively deflected slow waves were recorded. Their frequency, amplitude and conduction velocity were identical in the electrodes of the individual subject and were reproducible. The slow waves were followed or superimposed by fast activity spikes or action potentials which occurred randomly and were associated with urethral pressure rise. The pattern of electric activity was stable in the same subject on all test sessions.Conclusions: A normal electrourethrogram could be identified. It consisted of slow waves and action potentials. The waves had a regular rhythm. The action potentials appear to have a motor activity and are suggested to clear the urethra of the residual urine and secretions that may exist in the urethra after micturition. The clinical significance and diagnostic role of the electrourethrogram need to be further investigated.     

犬Oddi括约肌肌电的研究

目的探索能准确稳定记录犬Oddi括约肌(sphincter of Oddi,SO)肌电活动的新方法,并对记录到的肌电波形进行初步分析。方法用自行研制的黏膜接触式电极记录30只犬SO肌电活动,同时记录十二指肠和胃的肌电活动,分析SO肌电波形的规律以及和胃十二指肠肌电的关系。结果用我们的方法可以记录到犬SO的快波和慢波,同步记录以及切离实验证实记录到的波形是犬的SO肌电而不是来自十二指肠和胃。结论犬的SO肌电记录是可行的,犬SO快波和慢波的发现将对SO功能研究提供一个新的平台。     

Study of the rectal electric activity of the uninhibited rectal detrusor (overactive rectum): a new concept of pathogenesis

BACKGROUND/OBJECTIVE: One of the causes of fecal incontinence is uninhibited rectal detrusor syndrome (URDS). Patients with this condition either perceived the first rectal sensation after the onset of involuntary rectal contraction or not at all. We investigated the hypothesis that the abnormal rectal contractility in URDS may be caused by deranged rectal electric activity. METHODS: Twenty-five patients with URD (14 women and 11 men; age, 44.7 +/- 10.3 years) and 10 healthy volunteers (6 women and 4 men; age, 42.8 +/- 8.7 years) were studied. URDS was diagnosed by rectometry and provocative test. A transcutaneous EMG was performed with one electrode placed lateral to each sacroiliac joint and the third one midway between the greater trochanter and the ischial tuberosity. Two 20-minute recording sessions were performed for each subject. RESULTS: Slow waves (SWs) with regular rhythm and similar parameters (frequency, amplitude, conduction velocity) from the 3 electrodes were recorded from the healthy volunteers. They showed a significant increase in the parameters on saline filling of the rectum. The SWs of patients with URDS exhibited a "dysrhythmic" pattern with irregular parameters, which were different in the 3 electrodes and inconsistent during recording. They showed areas of tachyrhythmia, bradyrhythmia, and arrhythmia. On provoking rectal overactivity, the SWs showed an increased dysrhythmic activity. CONCLUSIONS: The patients with URD exhibited a "dysrhythmic" electric pattern with areas of variable electric activity. The tachyrhythmic areas seem to initiate the urgency and fecal incontinence of URDS. It is suggested that a disordered rectosigmoid pacemaker causes the dysrhythmic waves.     

Response of the internal reproductive organs to clitoral stimulation: the clitorouterine reflex

We investigated hypothesis that uterine erection, elevation and enlargement during sexual response are reflex and result from penis buffeting the glans clitoris (GC). In 23 healthy women, two recording electrodes were applied to the uterine mucosa and one to cervix uteri (CU). GC was stimulated electrically and mechanically by pencil electrode. The uterine and CU pressures were measured. Tests were repeated after anesthetization of the uterus or GC. Uterine electrodes recorded slow waves, followed by random bursts of action potentials (APs). No waves registered from CU. Electrical or mechanical GC stimulation eliminated uterine electric waves, but anesthetized GC did not, nor did GC stimulation while the uterus anesthetized. Uterine pressure declined on electrical or mechanical stimulation. Results suggest presence of reproducible reflex relationship between GC and the uterus, we call 'clitorouterine reflex'. GC buffeting seems to evoke reflex and initiate uterine responses. Reflex may prove of diagnostic significance in sexual disorders.     

Study of the Rectal Electric Activity of the Uninhibited Rectal Detrusor (Overactive Rectum): A New Concept of Pathogenesis

Abstract

Background/Objective: One of the causes of fecal incontinence is uninhibited rectal detrusor syndrome (URDS). Patients with this condition either perceived the first rectal sensation after the onset of involuntary rectal contraction or not at all. We investigated the hypothesis that the abnormal rectal contractility in URDS may be caused by deranged rectal electric activity.

Methods: Twenty-five patients with URD (14 women and 11 men; age, 44.7 ± 10.3 years) and 10 healthy volunteers (6 women and 4 men; age, 42.8 ± 8.7 years) were studied. URDS was diagnosed by rectometry and provocative test. A transcutaneous EMG was performed with one electrode placed lateral to each sacroiliac joint and the third one midway between the greater trochanter and the ischial tuberosity. Two 20- minute recording sessions were performed for each subject.

Results: Slow waves (SWs) with regular rhythm and similar parameters (frequency, amplitude, conduction velocity) from the 3 electrodes were recorded from the healthy volunteers. They showed a significant increase in the parameters on saline filling of the rectum. The SWs of patients with URDS exhibited a “dysrhythmic” pattern with irregular parameters, which were different in the 3 electrodes and inconsistent during recording. They showed areas of tachyrhythmia, bradyrhythmia, and arrhythmia. On provoking rectal overactivity, the SWs showed an increased dysrhythmic activity.

Conclusions: The patients with URD exhibited a “dysrhythmic” electric pattern with areas of variable electric activity. The tachyrhythmic areas seem to initiate the urgency and fecal incontinence of URDS. It is suggested that a disordered rectosigmoid pacemaker causes the dysrhythmic waves.     

Rectal pacing: pacing parameters required for rectal evacuation of normal and constipated subjects

BACKGROUND AND PURPOSE: Our previous studies have demonstrated that rectal electric waves start at the rectosigmoid junction (RSJ) and spread caudad along the rectum. A rectosigmoid pacemaker was postulated to exist at the RSJ. We also demonstrated that electric waves in rectal inertia are so scarce that a "silent" electrorectogram is recorded; the myoelectric activity in such cases was stimulated by an artificial pacemaker placed at the RSJ. For this article we investigated the pacing parameters necessary for rectal evacuation in rectal inertia patients. METHODS: The study comprised 24 patients with rectal inertia divided into two groups: study group (10 women, 6 men; mean age, 38.9 +/- 10.6 years) and control group (6 women, 2 men; mean age, 36.3 +/- 9.8 years). The main complaint was infrequent defecation and straining at stools. Eight healthy volunteers (6 women, 2 men; mean age, 37.2 +/- 9.4 years) with normal stool frequency were included in the study. Through a sigmoidoscope, an electrode was hooked to the RSJ (stimulating) and two electrodes were hooked to the rectal mucosa (recording). Rectal electric activity was recorded before (basal activity) and during electric stimulation of the RSJ electrode with an electrical stimulator delivering constant electric current of 5-mA amplitude and 200-ms pulse width. RESULTS: In the healthy volunteers, rectal pacing effected increases in frequency, amplitude, and velocity from a mean of 2.3 +/- 0.9 to 6.2 +/- 1.8 cycles/min (P < 0.01), 1.2 +/- 0.6 to 1.7 +/- 0.8 mV (P < 0.05), and 4.1 +/- 1. 2 to 6.3 +/- 1.7 cm/s (P < 0.05), respectively. No waves were recorded from rectal inertia patients at rest. Rectal pacing of the study group showed pacesetter potentials with a mean frequency of 2. 1 +/- 1.2 cycles/min, amplitude of 0.9 +/- 0.1 mV, and velocity of 3. 3 +/- 1.6 ms. The control group, in whom the pacemaker was not activated, showed no electric activity. CONCLUSIONS: Rectal pacing succeeded in producing myoelectric activity in patients with rectal inertia. It is therefore suggested that this method be applied for rectal evacuation in patients with inertia constipation.     

A genetic mechanism for cecal atresia: the role of the Fgf10 signaling pathway

BACKGROUND: Intestinal atresia represents a significant surgically correctable cause of intestinal obstruction in neonates. Intestinal development proceeds as a tube-like structure with differentiation along its axis. As the intestine differentiates, the cecum develops at the transition from small to large intestine. Fgf10 is known to serve a key role in budding morphogenesis; however, little is known about its role in the development of this transitional structure. Here we evaluate the effect of Fgf10/Fgfr2b invalidation on the developing cecum. MATERIALS AND METHODS: Wild-type C57Bl/6, Fgf10(-/-), and Fgfr2b(-/-) embryos harvested from timed pregnant mothers were analyzed for cecal phenotype, Fgf10 expression, and differentiation of smooth muscle actin. RESULTS: Wt cecal development is first evident at E11.5. FGF10 is discreetly expressed in the area of the developing cecum at early stages of development. One hundred percent of Fgf10(-/-) and Fgfr2b(-/-) mutant embryos demonstrate cecal atresia with absence of epithelial and muscular layers. The development of neighboring anatomical structures such as the ileocecal valve is not affected by Fgf10/Fgfr2b invalidation. CONCLUSIONS: FGF10 expression is localized to the cecum early in the normal development of the cecum. Fgf10(-/-) and Fgfr2b(-/-) mutant embryos demonstrate cecal atresia with complete penetrance. Epithelial and muscular layers of the cecum are not present in the atretic cecum. The Fgf10(-/-) and Fgfr2b(-/-) mutants represent a genetically reproducible animal model of autosomal recessive intestinal atresia.     

Electroorchidogram. A preliminary study of the electric activity of the testicles in dogs

Summary.  Since electric activity could be registered from various organs in the body, this study investigates the feasibility of recording such activity from the testicle. The testicles of 12 male dogs were exposed under anaesthesia and 3 electrodes were sutured to the tunica albuginea. In addition, transcutaneous recordings of the electric waves were performed. The effect of traumatic insult induced by testicular irradiation and by induction of hypogonadism on electric activity was studied. Spermatic cord clamping and orchidectomy was done to test their effect on the electric waves of the testicles. Electric waves were registered from the electrodes applied both directly and transcutaneously to the testicle. Each wave consisted of a negative followed by a positive deflection, with a mean frequency of 10.2±1.8 cycle s^-1 and amplitude of 56.6±8.4 μV. The waves recorded from the 6 electrodes applied (3 directly and 3 transcutaneously) in the same animal had similar amplitude and frequency readings. No abnormal waves were registered. After testicular irradiation or induction of hypogonadism, a 'silent' or 'dysrhythmic' electroorchidogram was obtained. Spermatic cord clamping did not change the normal electroorchidographic pattern. No waves were recorded after orchidectomy (silent electroorchidogram). To conclude, an electroorchidogram was configurated for the normal testicle. It showed changes after testicular insult. It is assumed that the electroorchidogram might reveal changes in the pathologic conditions of the testicle and this requires further study.     

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.     

Cecal volvulus in giant ventral hernia

IntroductionColonic volvulus is the third leading cause of the colonic obstruction with cecal volvulus accounting for approximately 40% of all colonic volvulus. Lack of peritonealization of the right colon, adhesions from prior surgery, colonic atony, and distal colonic obstruction are potential risks factors for the development of cecal volvulus.Prersentation of the case63 year old male with history of multiple prior intraabdominal surgeries and recurrent ventral hernia. Presented with colon perforation, as a result of cecal volvulus, which was contained in a giant ventral hernia. Diagnosis of cecal volvulus was suspected based on preoperative imaging studies, and confirmed in the OR. Patient underwent damage control procedure with subsequent challenging abdominal wall closure.DiscussionAxial cecal volvulus and cecal bascule are representing two types of cecal volvulus. Both of these types require a mobile cecum and presence of right colon to occur. It is generally accepted, that mobile cecum is a congenital condition, but in certain situations, particularly after prior intraabdominal surgeries, cecum may lose fixation points and potentially become vulnerable to twisting. This patient with long history of large recurrent ventral hernia had mobile cecum inside the hernia sac and developed cecal volvulus.ConclusionWe present a unique case of cecal volvulus in giant ventral hernia after multiple prior intraabdominal surgeries. Challenges in management of this exceptionally difficult patient were discussed. Large ventral hernia with mobile cecum inside hernia sac is a risk factor for cecal volvulus.