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Biomedical subjects

A Shafik

Publications and source records attributed to A Shafik.

At least 55 records · Page 3Linked to original sources
PubMed2000

Electrohepatogram in pathologic liver conditions.

We have recently studied the electric activity of the liver in both a normal canine model and in humans, and could characterize an electrohepatogram (EHG). Regular and reproducible slow waves or pacesetter potentials (PPs) were recorded. Hepatoarrhythmic electric activity was registered in liver insult of a canine model and in liver cirrhosis. The current communication studied the hepatic electric activity in liver diseases aiming at identifying an EHG for the different pathologic conditions, to be used as an investigative tool in their diagnosis. 55 subjects were studied: 10 with hepatocellular cancer (7 men, 3 women; age 53.7 years), 16 with acute hepatitis (10 men, 6 women; 42.2 years), 14 with metastatic liver deposits (9 men, 5 women; 53.1 years), and 15 healthy volunteers as controls (10 men, 5 women, 43.6 years). Three electrodes were placed 1.5 - 2 cm below and parallel to the costal margin and 4 to 5 cm apart. They were connected to a Beckman R611 recorder. At least two 20-minute recording sessions were performed for each subject. The PPs of the healthy volunteers exhibited a regular rhythm with identical and reproducible frequency and amplitude from the3 electrodes in the same subject. The EHG of the hepatocellular cancer patients showed a 'hepatoarrhythmic' pattern; the waves had irregular frequency and amplitude. In acute hepatitis 2 patterns were encountered: 'silent', which occurred in the preicteric and icteric stages, and 'hepatoarrhythmic' which occurred in the convalescent stage. The liver which had a few metastatic deposits exhibited a hepatoarrhythmic pattern and the liver with numerous deposits presented a 'silent' pattern. The aforementioned patterns were reproducible. In conclusion, different patterns were recorded in the various liver diseases. The patterns seem to reflect the liver cell function. A normal EHG was recorded from the healthy liver, while a silent EHG was registered from the presumably non-functioning liver cells. Hepatoarrhythmia occurred probably when the liver function was impaired. Electrohepatograhy is a simple, easy, non-invasive, and non-radiologic procedure. It is suggested to serve as an investigative tool in the diagnosis of liver diseases.

Adult↗
PubMed2000

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.

Action Potentials↗
PubMed2000

The role of the levator ani muscle in evacuation, sexual performance and pelvic floor disorders.

This paper reviews the role of the levator ani muscle (LAM) in evacuation, sexual performance and pelvic floor disorders. The LAM fixes the vesical neck, anorectal junction and vaginal fornices to the side wall of the pelvis by means of the suspensory sling and hiatal ligament. On contraction it shares in the mechanism of evacuation (urination, defecation). During the sexual act vaginal distension by the erect penis evokes the vaginolevator and vaginopuborectalis reflexes, with a resulting LAM contraction. The LAM also contracts upon stimulation of the clitoris or cervix uteri, an action mediated through clitoromotor and cervicomotor reflexes. LAM contraction leads to upper vagina ballooning, which acts as receptacle for semen collection, to uterine elevation and straightening and to elongation and narrowing of the vagina. These actions enhance the sexual response and prepare the uterus and vagina for the reproductive process. During ejaculation LAM contraction facilitates semen ejection. Levator subluxation and sagging leads to levator dysfunction syndrome, which may present as pudendal canal syndrome.

Female↗
PubMed2000

Rectal pacing in patients with constipation due to rectal inertia: technique and results.

In a previous study we determined the rectal pacing parameters needed for rectal evacuation in patients with rectal inertia. Here we investigated the effect of rectal pacing on rectal myoelectric activity, motility, and evacuation in ten patients with constipation due to rectal inertia. A pacemaker was implanted in a subcutaneous pocket above the inguinal area, with a lead threaded in the anal submucosa to be hooked at the rectosigmoid junction. The effect of rectal pacing on rectal electric activity was investigated by inserting two recording electrodes to the rectal mucosa. The patients were then trained for home pacing. No waves were recorded from the rectum at rest. On rectal pacing, slow waves or pacesetter potentials (mean frequency 2.3+/-1.1 cpm, amplitude 0.86+/-0.1 mV, velocity 3.4+/-1.6 ms) were registered after a latency period of 5.2+/-1.6 min. Rectal evacuation, on pacing, occurred in seven of the ten patients. The three who showed no significant response exhibited low wave parameters. Three of seven patients were able to evacuate spontaneously without pacing after having performed daily pacing for 5-6 months. The pacemaker was removed in six patients (three failures and three after spontaneous defecation). Thus rectal pacing succeeded in inducing rectal evacuation in 70% of the patients. The procedure failed in three patients. Three had spontaneous defecation after a few months of rectal pacing. No complications were encountered, and the method was tolerated and acceptable. Further studies on a large group of patients are required.

Action Potentials↗
PubMed2000

Magnetic stimulation of the cavernous nerve for the treatment of erectile dysfunction in humans.

A recent study in dogs has demonstrated that magnetic stimulation (MS) of the cavernous nerve produced an increase of the intracorporeal pressure and full penile erection. In view of these results, we tested the possible application of this procedure in humans with erectile dysfunction (ED). The study comprised 32 patients with ED (age 38.3 +/- 9.6 y) and 20 healthy volunteers (age 36.8 +/- 8.8 y). Routine erectile function tests suggested that impotence was neurogenic. A magnetic coil was placed over the dorsal aspect of the penis in the vicinity of the symphysis pubis. MS was performed using a stimulation of 40% intensity, 20 Hz frequency, 50 s on and 50 s off for 10 minutes duration. In the healthy volunteers, the coil was placed as aforementioned but was not activated. The intracorporeal pressure was recorded and penile tumescence and rigidity observed during MS in the patients and without stimulation in the controls. MS led to gradual increase in length and diameter of the penis until full erection was achieved; the penis became firm, rigid and pulsatile. The intracorporeal pressure increased significantly (P < 0.0001) at full erection. Mean latency to full erection was 19.3 +/- 3.4 s. Upon off-stimulation, penile erection and intracorporeal pressure returned to baseline after a mean of 22.7 +/- 3.2 s. Penile and pressure response to MS was resumed after an off-time of 50 s. The response was reproducible infinitely if the off-time was observed. The controls showed no penile tumescence or rigidity or increase of the intracorporeal pressure. In conclusion, MS of the cavernous nerve is effective in inducing penile rigidity. It is a simple, easy and non-invasive method which has no adverse effects. It might prove to be suitable for application in patients with ED.

Adult↗
PubMed2000

The anocavernosal erectile dysfunction syndrome. II Anal fissure and erectile dysfunction.

A previous study has demonstrated that the bulbocavernosus muscle (BCM) is a part of the external anal sphincter (EAS) [Shafik, Arch Androl, 1999]. It aids erection by compressing the penile bulb and the dorsal penile vein, and acts as a 'suction-ejection' pump in the ejaculatory process. Being a part of the EAS, the BCM is assumed to be involved in the different EAS pathologies. A recent study showed that erectile (ED) and ejaculatory dysfunction in 16 men with fecal incontinence (FI) after an anal fistula operation was cured after sphincteroplasty [Shafik, in press]. This article investigates the erectile and ejaculatory status in patients with anal fissure. The study comprised 32 men with acute anal fissure (mean age 36.7 +/- 8.2 s.d. years), 21 with chronic anal fissure (mean age 38.8 +/- 10.3 s.d. years), and 10 healthy volunteers (mean age 35.2 +/- 7.3 s.d. years). Erectile dysfunction occurred in all men with an acute fissure and in 16 of the chronic fissure patients; erection had been normal before fissure occurrence. The volunteers had normal erection. The anal pain radiated to the penis and was exaggerated on erection and penile thrusting. Erectile dysfunction investigations showed normal results. The electromyographic (EMG) activity of the external and internal (IAS) anal sphincters and the BCM as well as anal, penile bulb and cavernosal pressures were recorded. The acute fissures were treated conservatively and chronic ones by internal anal sphincterotomy. The patients were followed for mean periods of 17.3 +/- 3.6 s.d. months. The bulbocavernosus reflex as well as EMG activity of EAS and BCM were normal, while the resting EMG activity of the IAS was increased. The anal pressure in the acute and chronic anal fissure was increased (P < 0.01, P < 0.05, respectively), while the bulbar and cavernosal pressures showed no significant changes. Fissure treatment effected cure of the fissure and the ED in 30/32 of the acute and in 19/21 of the chronic cases. Erectile dysfunction persisted in the four patients in whom the fissures did not heal. In conclusion, a relationship is suggested to exist between anal fissure and ED. The ED occurred in the presence of anal fissure and was normalized with fissure cure. The BCM and anal pain seem to play a role in the etiology of ED associated with anal fissure.

Adult↗
PubMed2000

Vaginismus: results of treatment with botulin toxin.

In view of the long-term therapy necessary to cure vaginismus and specially persistent cases, we considered using botulin toxin (BT) injections for the treatment of such cases. Eight women (mean age 26.6 +/- 1.2 years) with vaginismus were treated with BT. Another five women with vaginismus, matching the eight patients in age, acted as controls. The patients in the study group were injected with BT (25 IU diluted in 1 ml saline) into each of the two bulbospongiosus muscles. Control patients were injected with saline. Mean follow-up was 10.2 +/- 3.3 months. All the patients injected with BT improved. The couples could achieve satisfactory intromission. No patient was in need of re-injection and there was no recurrence during the follow-up period. Control subjects did not improve with the saline injection into the bulbospongiosus muscle. In conclusion, BT injection effected cure in all of the vaginismus patients with no complications or recurrence. The technique is simple, easy, cost-effective, not time-consuming and can be achieved on an outpatient basis.

Journal Article↗
PubMed2000

Suppression of uninhibited rectal detrusor by functional magnetic stimulation of sacral root.

PURPOSE: To demonstrate the effect of sacral magnetic stimulation (MS) on the uninhibited rectal detrusor aiming at suppression of unstable rectal contractions. METHODS: The study was comprised of 6 patients (3 women, 3 men, ages between 32 and 49 years) with supraconal spinal cord injury who complained of fecal incontinence. Rectal sensation for defecation was felt after the onset of involuntary detrusor contraction in 4 patients and not perceived in 2. Rectal and rectal neck pressures were normal. Rectal hyperreflexia was provoked by rapid saline infusion into the rectum (100 to 150 ml; 15 ml/s). Sacral MS was effected by a magnetic coil and a stimulator. The coil was applied to the back between L-4 and L-5. RESULTS: During the provocative saline test, the rectal pressure showed a significant increase (p < .001) and the subjects evacuated the infused saline involuntarily; the rectal neck pressure showed no significant change (p > .05). Intermittent MS during the induced rectal pressure rise using 70% of maximal intensity (i.e., 175 Joules per pulse, 40 Hz frequency, and 2 second burst length with 2 seconds off) affected rectal pressure decline (p < .01) and no saline evacuation. CONCLUSIONS: Sacral MS produced inhibition of provoked rectal hyperreflex contractions in patients with supraconal cord injuries. The method is simple, easy, noninvasive, and with no adverse effects.

Adult↗
PubMed2000

Neuronal innervation of urethral and anal sphincters: surgical anatomy and clinical implications.

The present review describes the neuronal innervation of the external urethral and anal sphincters. A knowledge of this innervation helps in understanding the clinical symptoms of urinary and anorectal pathology, and in choosing the appropriate technique of nerve localization or block. An ability to locate the pudendal nerve, on the basis of surgically documented anatomy, has important diagnostic and therapeutic advantages. It can be used to study the integrity of pelvic floor muscles, in biofeedback training, nerve blocks, pudendal canal decompression, chronic stimulation trials to treat urinary or faecal incontinence, and in nerve conduction studies or evoked potential recordings. Furthermore, the superficial location of the sphincteric innervation in the perineum and ischiorectal fossa renders the nerve branches susceptible to injury during operative correction of urinary or faecal incontinence. Supported by a knowledge of anatomy, we can make firm recommendations on which to base safe surgical techniques that avoid damage to urethral and anal sphincteric innervation.

Anal Canal↗
PubMed2000

Effect of sigmoid colon distension on the rectosigmoid junction. Description of the rectosigmoid junction tightening reflex and its clinical implications.

PURPOSE: The sigmoid colon (SC) is the site of stool storage. The stools accumulate in the SC until, at a certain volume, the mechanoreceptors in the SC wall are stimulated, evoking the sigmoidorectal junction inhibitory reflex with a resulting SC contraction, rectosigmoid junction (RSJ) relaxation and passage of the stools to the rectum. However, the RSJ status during stool accumulation in the SC has been scarcely addressed in the literature. The current study investigated this point. METHODS: A balloon-ended tube was introduced into the SC of 21 healthy volunteers [mean age (+/- SD) 36.8 +/- 10.3 years; 15 men and 6 women]. The pressures in the SC and RSJ were measured by means of a perfused tube, at rest and during balloon inflation with carbon dioxide at two rates: slow (3 ml/min) and rapid (150 ml/min). The tests were repeated after individual anesthetization of the SC and RSJ. RESULTS: During slow SC distension up to 80 ml included, the RSJ pressure progressively increased while the SC exhibited no pressure response (p > 0.05). At a distending volume of 100 ml, the pressure in the SC rose (p < 0. 01) and declined in the RSJ (p < 0.05), and the balloon was dispelled to the rectum. Rapid SC distension up to 40 ml included, effected no SC pressure response (p > 0.05) while the RSJ showed progressive pressure elevation. At 60 ml distension, the SC recorded a pressure rise (p < 0.001) and the RSJ a pressure decrease (p < 0. 05); the balloon was dispelled to the rectum. The pressure in the RSJ did not respond to distension of the anesthetized SC. CONCLUSION: The study has shown that, during accumulation of stools in the SC, leakage to the rectum seems to be prevented by a reflex action which we call 'rectosigmoid junction tightening reflex'. This reflex probably acts to control both storage and emptying of the SC contents. Reflex dysfunction might lead to defecation disorders. We suggest that the RSJ tightening reflex be included as an investigative tool in the diagnosis of defecation disorders.

Adult↗
PubMed2000

Sacral magnetic stimulation in paradoxical puborectalis syndrome.

BACKGROUND/PURPOSE: Our earlier studies have demonstrated that sacral magnetic stimulation (MS) in the canine model, in healthy volunteers and in constipated subjects brought about a rise in rectal pressure and a decline in rectal neck (anal canal) pressure as well as rectal evacuation. Based on these results, we studied the effect of sacral MS on defecation in patients with paradoxical puborectalis syndrome (PPS). METHODS: Eleven subjects (8 women, 3 men; age 36-53 years) with PPS were enrolled in the study. The magnetic coil was placed on the back with its center located between L4 and L5. Stimulation parameters were set at 70% of maximum intensity, 40 Hz frequency and 2 s burst length with 2 s off. During MS, the rectal neck and gastric (intra-abdominal) pressures were measured. The procedure was performed in the empty and the full rectum using the balloon expulsion test in the latter. RESULTS: MS of the empty and balloon-filled rectum brought about a rise in the rectal pressure (p < 0.001), decline in rectal neck pressure (p < 0. 001) and no significant change in intragastric pressure (p > 0.05). The balloon was expelled by all patients. CONCLUSIONS: Sacral MS succeeded in expelling the water-filled rectal balloon. The method is simple, easy, noninvasive, nonradiologic and can be performed on an outpatient basis in the treatment of PPS.

Adult↗
PubMed2000

Effect of magnetic stimulation on the contractile activity of the rectum in humans.

Magnetic stimulation (MS) has been used to activate the neuromuscular tissue by inducing an electric field. Based on the results of a recent study on a canine model (Eur Surg Res 1998;30:268-72), which demonstrated that sacral MS effected a rectal and vesical pressure rise and a drop of rectal neck (anal canal) pressure, thereby achieving evacuation, the test was performed on 28 healthy volunteers (mean age, 36.6 years; 18 men and 10 women). The rectal, rectal neck, and vesical pressures were recorded during sacral MS with a magnetic coil while the rectum was empty and distended by a balloon. Electromyographic activity of the two rectus abdominis muscles was determined to exclude the possible interference of intra-abdominal pressure with the MS recordings. Stimulation parameters were set at 70 per cent intensity, 40-Hz frequency, and 1-to 2-second burst length. Sacral MS effected significant rectal and vesical pressure rise (P < 0.01 and P < 0.01, respectively) and drop of rectal neck pressure (P < 0.01). Intermittent stimulation induced balloon expulsion from the rectum. The two rectus abdominis muscles did not show change in electromyographic activity during MS, indicating that the rectal and vesical pressure rise was not due to increased intra-abdominal pressure. Sacral MS induced rectal evacuation with no adverse effects. The method is simple, easy, safe, and noninvasive and is suggested to be applied for the treatment of the inertic or neuropathic rectum. As the vesical pressure proved to be elevated too, MS might also be used for rectal and vesical evacuation in patients with spinal cord lesions.

Adolescent↗
PubMed2000

Levator ani muscle activity in pregnancy and the postpartum period: a myoelectric study.

The levator ani (LA) is a muscle of evacuation and acts as well to support the pelvic viscera. An increase of the intra-abdominal pressure beyond the physiologic limits and visceral overload are speculated to interfere with LA functional activity. This consideration was a stimulus to study the effect of pregnancy on the LA muscle. The EMG activity of the LA muscle was recorded before and during pregnancy and after delivery in 36 women (mean age 27.2+/-3.1 years, 20 multigravida, 16 primigravida). A needle electrode was inserted into the muscle and LA activity was recorded at rest, and on squeezing and straining in both the erect and recumbent position. In the erect position, the resting and squeezing EMG activity during the first 8 weeks of pregnancy, showed no significant difference (p>0.05) from that before pregnancy, and after that, increased progressively and significantly until delivery. On straining, the EMG activity showed no significant difference from that before pregnancy in the first 8 weeks, and after that, decreased progressively and significantly till delivery. In the recumbent position, the LA EMG registered similar activity to that in the erect position but with significantly lower values (p<0.05). The reduction in the LA EMG activity was more evident in the multi-than in the primigravida. In the postpartum period, no LA EMG activity was recorded in the first month; the activity increased progressively after that time to reach the pre-pregnancy level in the forth postpartum month. In conclusion, pregnancy interferes with EMG and functional activity of the LA from the 8th week onwards due to the progressively increasing size and weight of the uterus. This effect was most marked in the last 12 weeks. Delivery seems to maximally inhibit the LA activity in the first postpartum month. Excessive LA traumatization may eventually lead to levator dysfunction syndrome.

Adult↗
PubMed2000

Esophageal and gastric motile response to rectal distension with identification of a recto-esophagogastric reflex.

PURPOSE: To investigate the effect of rectal distension with a balloon simulating fecal mass, on the motile activity of the esophagus and stomach. METHOD: Nine healthy volunteers (7 men, 2 women, mean age 46.6 +/- 4.7 years) were studied. A manometric tube was introduced into the stomach and a balloon-tipped catheter into the rectum. The gastric and esophageal pressure response to rectal distension in increments of 10 ml up to 80 ml of water was recorded. The test was repeated after rectal anesthetization. RESULTS: There was no esophageal or gastric pressure response to rectal distension up to 70 ml. At 80 ml distension, the rectal pressure rose (p < 0.001) and the balloon was dispelled to the exterior. Meanwhile, the pressure in the esophagus, corpus of the stomach and pyloric antrum showed a significant drop (p < 0.05) and in the lower esophageal sphincter and pyloric sphincter a significant rise (p < 0.05). There was no esophageal or gastric response to distension of the anesthetized rectum. CONCLUSION: Lower esophageal and pyloric sphincter contraction and esophageal and gastric relaxation during rectal distension appear to delay gastric emptying. The response of the esophagus and stomach to rectal distension seems to be elicited by a reflex which we call "recto-esophagogastric reflex". It is suggested that rectal lesions or dysfunction might disturb the esophageal or gastric motility and vice versa. The reflex may therefore prove to be of significance in the diagnosis of such disorders.

Adult↗
PubMed2000

Is myoelectric activity transmittable from one muscle to another: an experimental study.

BACKGROUND: In contrast to other striated muscles in the body, pelvic floor muscles possess resting electric activity. We have demonstrated that this activity was due to smooth muscle fibers detected in the levator ani muscle (LAM) which presumably develop in adaptation to variations in the intraabdominal pressure and visceral weight action. AIMS: The current communication tries to answer the question whether this resting myoelectric activity is transmittable to other muscles which lack such activity. METHODS: The LAM and obturator internus muscle (OIM) were exposed in 14 mongrel dogs through a paraanal incision. The resting EMG activity of both muscles was recorded. The border of the LAM closest to its origin at the white line, was released and sutured to the obturator fascia. The EMG activity of both the LAM and OIM was recorded at rest and on LAM stimulation. The EMG recording was repeated after suturing of the LAM to the OIM whose fascia had been removed. The test was repeated after LAM anesthetization. RESULTS: Resting and stimulated EMG activity was recorded in the LAM, but not in the OIM, before and after suturing the LAM to the obturator fascia. On removing the obturator fascia, both muscles recorded similar EMG activity at rest and on LAM stimulation (p > 0.05, p > 0.05, respectively). Thirty minutes from LAM anesthetization both muscles showed no EMG activity at rest or on LAM stimulation; after 3 hours, the 2 muscles recorded an activity similar to that before anesthetization (p > 0.05). CONCLUSION: The myoelectric activity can be transmitted to defasciated muscles. This finding may be useful in electrostimulation therapy and in developing type 1 fibers in striated muscles.

Animals↗