20 results on '"Ahmed SHAFIK"'
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2. Innovative passive aeration process for synthetic deoxygenated water
- Author
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Sabry, Tarek Ismail Mahmoud, primary, El-Gendy, Ahmed Shafik, additional, Naguib, AlaaEldin Hisham Mohamed, additional, and Ahmed Khafaga, Ahmed Mohamed, additional
- Published
- 2023
- Full Text
- View/download PDF
3. Comparison of the Clinical Efficacy of Abobotulinumtoxin A (ABO) and Onabotulinumtoxin A (ONA) in the Treatment of Crow’s Feet Wrinkles: A Split-Face Study
- Author
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Elridy, Ahmed Shafik, primary, Zaki, Rania Gamal Eldin, additional, and Elshinawy, Reham Fawzy, additional
- Published
- 2017
- Full Text
- View/download PDF
4. Electromyographic Lag Time and Opening Time: Two Novel Noninvasive Methods to Investigate Patients with Anal Outlet Obstruction and Their Response to Treatment
- Author
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Ali A. Shafik, Olfat El Sibai, Ahmed Shafik, and Ismail A. Shafik
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Adult ,Male ,medicine.medical_specialty ,Time Factors ,Constipation ,External anal sphincter ,Anal Canal ,Electromyography ,Distension ,Balloon ,Pelvic Floor Muscle ,medicine ,Humans ,Pelvic floor ,medicine.diagnostic_test ,business.industry ,Biofeedback, Psychology ,Pelvic Floor ,Middle Aged ,Surgery ,body regions ,medicine.anatomical_structure ,Female ,medicine.symptom ,Rectal Balloon ,business - Abstract
Methods in use can diagnose anal outlet obstruction but not degree of obstruction. We introduced two novel noninvasive methods of diagnosing and evaluating the degree of anal outlet obstruction: pelvic floor electromyographic lag time and opening time. Pelvic floor electromyographic lag time measured time interval between start of pelvic floor muscle relaxation and start of anal outlet flow. Opening time calculated time lapse between start of rectal contraction and start of anal outlet flow. We investigated the hypothesis that pelvic floor electromyographic lag time and opening time can be used as investigative tools in diagnosing and evaluating degree of anal outlet obstruction. Thirty-one patients with anal outlet obstruction and 26 healthy volunteers were studied. Electromyography of external anal sphincter and anal and rectal pressures were recorded on rectal balloon distension until balloon was expelled. Pelvic floor electromyographic lag time and opening time were measured. Mean opening time and pelvic floor electromyographic lag time of the anal outlet obstruction patients showed significant increase compared to those of healthy volunteers. Pelvic floor electromyographic lag time was longer than opening time in both patients and controls, but the difference was not significant. Biofeedback effected improvement in 24 of the 31 patients. Thus, two novel investigative tools -- opening time and pelvic floor electromyographic lag time -- in diagnosis of anal outlet obstruction are presented. They exhibited significant increase in anal outlet obstruction patients over the healthy volunteers. There was no significant difference between pelvic floor electromyographic lag time and opening time readings.
- Published
- 2007
5. SPERM DNA FRAGMENTATION
- Author
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Ali A. Shafik, O. El Sibai, Ismail A. Shafik, and Ahmed Shafik
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Male ,media_common.quotation_subject ,Apoptosis ,Fertility ,Semen ,DNA Fragmentation ,Biology ,Semen analysis ,Bioinformatics ,Male infertility ,Andrology ,Semen quality ,Endocrinology ,medicine ,Humans ,Infertility, Male ,media_common ,medicine.diagnostic_test ,urogenital system ,medicine.disease ,Spermatozoa ,Sperm ,Chromatin ,Genetic Techniques ,DNA fragmentation ,Reagent Kits, Diagnostic - Abstract
Several techniques have been developed to measure the amount of sperm DNA damage in an effort to identify more objective parameters for evaluation of infertile men. The integrity of sperm DNA influences a couple's fertility and helps predict the chances of pregnancy and its successful outcome. The available tests of sperm DNA damage require additional large-scale clinical trails before their integration into routine clinical practice. The physiological/molecular integrity of sperm DNA is a novel parameter of semen quality and a potential fertility predictor. Although DNA integrity assessment appears to be a logical biomarker of sperm quality, it is not being assessed as a routine part of semen analysis by clinical andrologists. Extensive investigation has been conducted for the comparative evolution of these techniques. However, some of these techniques require expensive instrumentation for optimal and unbiased analysis, are labor intensive, or require the use of enzymes whose activity and accessibility to DNA breaks may be irregular. Thus, these techniques are recommended for basic research rather than for routine andrology laboratories. Sperm chromatin structure evaluation is applied to detect male factors that may affect the chance of success with IVF as well as natural fertility. Further research is needed to define the optimal test of sperm chromatin structure. The clinical application of this test will evolve as well.
- Published
- 2006
6. The 'Opening Time' and 'Pelvic Floor Electromyographic Lag Time': Two Novel Tools in the Assessment of the Anorectal Evacuation Time
- Author
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Ahmed Shafik, Ali A. Shafik, Olfat El Sibai, and Ismail A. Shafik
- Subjects
Adult ,Male ,Time Factors ,External anal sphincter ,Muscle Relaxation ,Anal Canal ,Rectum ,Distension ,Catheterization ,Humans ,Medicine ,Defecation ,Pelvic floor ,Electromyography ,business.industry ,Pelvic Floor ,Anatomy ,Anal canal ,body regions ,Muscle relaxation ,medicine.anatomical_structure ,Female ,Surgery ,Rectal Balloon ,business ,Muscle Contraction - Abstract
Rectal evacuation necessitates rectal contraction and pelvic floor muscles relaxation; it is not known which action precedes the other. We investigated the hypothesis that pelvic floor muscles relaxation precedes rectal contraction so that rectal contents find the anal canal already opened. Electromyographic activity of the external anal sphincter as well as anal and rectal pressures were recorded during rectal balloon distension and evacuation. Pelvic floor muscles electromyographic lag time (time from start of pelvic floor muscles relaxation to start of evacuation) and opening time (time from start of rectal contraction to start of evacuation) were measured. Rectal balloon distension in increments of 20 mL up to 100 mL effected progressive increase of both external anal sphincter electromyography and anal pressure. At 120 mL balloon distension up to 180 mL, external anal sphincter electromyography and anal pressure exhibited gradual decrease whereas rectal pressure showed no changes. At 200 to 220 mL rectal balloon distension, rectal pressure increased and anal pressure decreased, while external anal sphincter showed no electromyographic activity; rectal balloon was expelled. The opening time recorded a mean of 1.8 +/- 0.7 s and pelvic floor muscles electromyographic lag time of 2.2 +/- 0.9; the two recordings showed no significant difference (p > .05). These, two diagnostic tools in anorectal investigations are presented: the opening time and pelvic floor muscles electromyographic lag time. Pelvic floor muscles relaxation preceded rectal contraction. As there is no significant difference between opening time and pelvic floor muscles electromyographic lag time, it appears easier to apply the latter as it is simple, objective, and noninvasive.
- Published
- 2006
7. Study of the Rectal Electric Activity of the Uninhibited Rectal Detrusor (Overactive Rectum): A New Concept of Pathogenesis
- Author
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Ismail Ahmed, Olfat El Sibai, Ali A. Shafik, Randa M. Mostafa, and Ahmed Shafik
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Rectum ,Electromyography ,Nerve conduction velocity ,Physical Stimulation ,medicine ,Humans ,Fecal incontinence ,Saline ,Sacroiliac joint ,Reflex, Abnormal ,medicine.diagnostic_test ,business.industry ,Muscle, Smooth ,Middle Aged ,Ischial tuberosity ,Surgery ,medicine.anatomical_structure ,Case-Control Studies ,Anesthesia ,Reflex ,Female ,Neurology (clinical) ,medicine.symptom ,business ,Fecal Incontinence ,Muscle Contraction - 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.
- Published
- 2005
8. Effect of Micturition on the External Anal Sphincter: Identification of the Urethro-Anal Reflex
- Author
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Ismail A. Shafik, Olfat El-Sibai, Ahmed Shafik, and Ali A. Shafik
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Adult ,Male ,medicine.medical_specialty ,External anal sphincter ,media_common.quotation_subject ,Urology ,Anal Canal ,Urination ,External sphincter muscle of female urethra ,urologic and male genital diseases ,Urethra ,Reflex ,medicine ,Flatulence ,Humans ,Fecal incontinence ,Defecation ,media_common ,Electromyography ,urogenital system ,business.industry ,Urethral sphincter ,Anal wink ,Muscle, Smooth ,Original Contribution ,Middle Aged ,Anal canal ,Electric Stimulation ,medicine.anatomical_structure ,Female ,Neurology (clinical) ,medicine.symptom ,business ,Fecal Incontinence ,Muscle Contraction - Abstract
A study on the response of the external anal sphincter (EAS) to the passage of urine through the urethra during micturition could not be found in the literature. We investigated the hypothesis that urine passage through the urethra effects EAS contraction to guard against possible flatus or stool leakage during micturition.The study was performed in 23 healthy volunteers (age, 38.6 +/- 10.8 [SD] years; 14 men and 9 women). The EAS electromyogram (EMG) was performed during micturition by surface electrodes applied to the EAS. Also, the EAS EMG response to urethral stimulation by a catheter-mounted electrode was registered. The test was repeated after individual anesthetization of the EAS and urethra.The EAS EMG recorded a significant increase (P0.01) during micturition and on urethral stimulation at the bladder neck. Stimulation of the prostatic, membranous, or penile urethra produced no significant change in the EAS EMG. Urethral stimulation after individual EAS and urethral anesthetization did not cause any changes in the EAS EMG.Urine passing through the urethra or urethral stimulation at the vesical neck produced an increase in the EAS EMG, which presumably denotes EAS contraction, which seems to guard against flatus or fecal leakage during micturition. EAS contraction on urethral stimulation is suggested to be mediated through a urethro-anal reflex. Further studies on this issue may potentially prove the diagnostic significance of this reflex in micturition and defecation disorders.
- Published
- 2005
9. URETHRAL SPHINCTERS RESPONSE TO CAVERNOSUS MUSCLES STIMULATION WITH IDENTIFICATION OF CAVERNOSO-URETHRAL REFLEX
- Author
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Ahmed Shafik, O. El Sibai, Ismail A. Shafik, and Ali A. Shafik
- Subjects
Adult ,Male ,Retrograde ejaculation ,media_common.quotation_subject ,Electromyography ,Urination ,Endocrinology ,Urethra ,Reference Values ,Reflex ,Humans ,Medicine ,Orgasm ,media_common ,Urinary bladder ,medicine.diagnostic_test ,business.industry ,Penile Erection ,Urethral sphincter ,Muscle, Smooth ,Anatomy ,medicine.disease ,Parity ,medicine.anatomical_structure ,Sphincter ,Female ,business - Abstract
The functional activity of the urethral sphincters during cavernosus muscles' contraction at coitus has been poorly addressed in the literature. We investigated the hypothesis that cavernosus muscles' contraction affects reflex contraction of the urethral sphincters to guard against semen reflux into the urinary bladder or urine leakage from the bladder during orgasm and ejaculation. The electromyographic (EMG) response of the external (EUS) and internal (IUS) urethral sphincters to ischio- (ICM) and bulbo- (BCM) cavernosus muscle stimulation was studied in 15 healthy volunteers (9 men, 6 women, age 39.3 +/- 8.2 SD years). An electrode was applied to each of ICM and BCM (stimulating electrodes) and the 2 urethral sphincters (recording electrodes). The test was repeated after individual anesthetization of the urethral sphincters and the 2 cavernosus muscles, and after using saline instead of lidocaine. Upon stimulation of each of the 2 cavernosus muscles, the EUS and IUS recorded increased EMG activity. Repeated cavernosus muscles' stimulation evoked the urethral sphincteric response without fatigue. The urethral sphincters did not respond to stimulation of the anesthetized cavernosus muscles nor did the anesthetized urethral sphincters respond to cavernosus muscle stimulation. Saline infiltration instead of lidocaine did not affect the urethral sphincteric response to cavernosal muscle stimulation. Results were reproducible. Cavernosus muscles' contraction is suggested to effect EUS and IUS contraction. This action seems to be reflex and mediated through the 'cavernoso-urethral reflex.' Urethral sphincters contraction upon cavernosus muscles contraction during sexual intercourse presumably prevents urine leak from the urinary bladder to urethra, prevents retrograde ejaculation, and propels ejaculate from the posterior to the penile urethra. The cavernoso-urethral reflex can act a diagnostic tool in the investigations of patients with ejaculatory disorders.
- Published
- 2005
10. Effect of Straining on the Lower Esophageal Sphincter: Identification of the 'Straining-Esophageal Reflex' and Its Role in Gastroesophageal Competence Mechanism
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Ismail A. Shafik, Olfat El-Sibai, Ali A. Shafik, Ahmed Shafik, and Randa M. Mostafa
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Adult ,Male ,Abdominal Hernia ,medicine.medical_treatment ,Action Potentials ,Electromyography ,Esophageal Sphincter, Lower ,Abdomen ,Reflex ,Pressure ,otorhinolaryngologic diseases ,medicine ,Humans ,Anesthetics, Local ,Saline ,Lower esophagus ,medicine.diagnostic_test ,business.industry ,Reflux ,Lidocaine ,Middle Aged ,Hernia, Abdominal ,body regions ,Cough ,Anesthesia ,Swallowing problems ,Gastroesophageal Reflux ,Esophageal sphincter ,Female ,Surgery ,business - Abstract
The lower esophagus is intra-abdominal and exposed to intra-abdominal pressure (IAP) variations that may lead to gastroesophageal reflux (GER). We investigated the hypothesis that the lower esophageal sphincter (LES) undergoes phasic contraction on IAP increase, with a resulting inhibition of the stress GER. The study comprised 17 subjects (age 42.3 +/- 8.7 SD yr, 10 men, 7 women) who were scheduled for surgical repair of abdominal hernia. The patients had no swallowing problems. The electromyographic (EMG) activity of the LES and pressure within the LES were recorded at rest and during increased IAP (coughing, straining). The recording was repeated after LES anesthetization or saline infiltration. The LES EMG at rest showed regular slow waves (SWs), superimposed on or followed by random action potentials (APs). Coughing or straining induced increase of the SWs parameters and also of the APs; although the increase with straining was less than with coughing, the difference was insignificant. Coughing or straining increased the LES pressure significantly (p.05, p.05, respectively). Ten minutes after LES anesthetization, coughing or straining did not produce significant LES EMG or pressure changes, while saline infiltration of LES caused LES response similar to preinjection. Thus, coughing and straining effected an increase of the LES EMG activity and pressure, an action presumably mediated through a reflex that we call the "straining-esophageal reflex." This reflex seems to be evoked during increased intra-abdominal pressure and to effect LES contraction, thus, sharing with other factors in prevention of gastroesophageal reflux.
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- 2004
11. Electrophysiologic Identification of the Location of the Colonic Pacemakers in Humans: Further Study
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Olfat El-Sibai, Ismail Ahmed, Ali A. Shafik, and Ahmed Shafik
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Adult ,Male ,Action Potentials ,Descending colon ,Cecum ,Biological Clocks ,Terminal ileum ,medicine ,Humans ,Motor activity ,Anesthetics, Local ,Peristalsis ,Colonic inertia ,business.industry ,Lidocaine ,Anatomy ,Middle Aged ,digestive system diseases ,Colon, Descending ,Electrophysiology ,medicine.anatomical_structure ,Female ,Surgery ,Gastrointestinal Motility ,business ,Colonic motility ,Colon, Transverse - Abstract
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.
- Published
- 2003
12. Role Of Positive Anorectal Feedback In Rectal Evacuation: The Concept Of A Second Defecation Reflex: The Anorectal Reflex
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Ali A. Shafik, Ismail Ahmed, and Ahmed Shafik
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Adult ,Male ,Reflex, Stretch ,medicine.medical_specialty ,Constipation ,Contraction (grammar) ,Manometry ,Anal Canal ,Feedback ,Pulmonary stretch receptors ,Reference Values ,Isometric Contraction ,medicine ,Humans ,Defecation ,Spinal Cord Injuries ,Reflex, Abnormal ,business.industry ,Rectum ,Middle Aged ,Surgery ,Spinal Cord ,Reference values ,Anesthesia ,Reflex ,Female ,Neurology (clinical) ,medicine.symptom ,business ,Mechanoreceptors - Abstract
The present study investigated the hypothesis that rectal contraction is maintained by positive anorectal feedback elicited by continuous passage of stools through the rectal neck (anal canal), and that cessation of stool passage aborts rectal contraction.Anal and rectal pressures were measured in 18 healthy volunteers (mean age = 38.6 years; 10 men, 8 women) during evacuation of saline infused into the rectum. Residual fluid volume was calculated. The test was repeated after separate application of lidocaine or bland gel to the rectal neck.On evacuation, fluid emanated from the rectal neck in continuous flow with no, or mild, straining. No residual saline was collected from 16 of 18 participants. After anal anesthetization, evacuation occurred in gushes induced with excessive straining; residual fluid was huge. Repetition of the test 2 hours after anesthetization produced the same results as before anesthetization. Bland gel applied to the rectal neck yielded results similar to those before gel application.Rectal contraction at defecation is suggested to be maintained by positive anorectal feedback evoked by continuous passage of stool through the rectal neck. This feedback appears to be affected through an anorectal excitatory reflex (ARR), which produces rectal contraction upon stimulation of anal stretch receptors. Abortion of this reflex by anal anesthetization seems to result in failure of the rectum to contract and in excessive straining to achieve rectal evacuation. ARR thus is suggested to be a second defecation reflex necessary to continue defecation, whereas the rectoanal inhibitory reflex is the primary reflex. The role of the ARR in pathogenesis of constipation and its utility in spinal cord injury need to be investigated.
- Published
- 2003
13. The 'Uninhibited Rectum': A Cause Of Fecal Incontinence
- Author
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Ali Ahmed and Ahmed Shafik
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Manometry ,Sensation ,Urology ,Anal Canal ,Rectum ,Catheterization ,fluids and secretions ,Humans ,Medicine ,Fecal incontinence ,In patient ,Defecation ,Idiopathic fecal incontinence ,business.industry ,Middle Aged ,Rectal Diseases ,medicine.anatomical_structure ,Female ,Neurology (clinical) ,medicine.symptom ,business ,Fecal Incontinence ,Muscle Contraction - Abstract
The uninhibited (unstable) rectum has been defined as a cause offecal incontinence (FI) in patients with supraconal lesions. In this study, we tested the hypothesis that the uninhibited rectum may be a cause of FI in patients with normal anal pressure and sphincteric mechanism who were considered to have idiopathic FI.The study comprised 82 patients (mean age 38.2 +/- 11.2 years; 58 women and 24 men) with idiopathic FI and a control group of 20 healthy volunteers (mean age 36.3 +/- 10.6 years; 14 women and 6 men). Inclusion criteria for FI patients were normal electromyogram of the external anal sphincter and puborectalis muscle, and normal anal sensation, pressure, and endosonography. Rectometry was performed using rectal balloon inflation with CO2 at a rate of 150 cc/min. Rectometrograms were assessed quantitatively and qualitatively.In 79 FI patients, the first rectal sensation was not felt. Urge was perceived at the time of balloon expulsion, which could not be prevented by voluntary sphincteric squeeze. In the remaining 3 patients, the first sensation was perceived but urge coincided with balloon expulsion. Rectometrography showed moderate and gross fluctuations in the tone limb that were not associated with significant changes in intra-abdominal pressure. This contrasted with normal subjects in whom the tone limb exhibited no fluctuations or minor fluctuations that roughly paralleled the intra-abdominal pressure fluctuations. The rectal distension volume at balloon expulsion was significantly lower in FI patients than in controls (P.05).These findings suggest that FI can be explained by the fact that the first rectal sensation was that of urge, which was perceived synchronously with balloon expulsion. That is, the balloon had been expelled before the patient could voluntarily squeeze the sphincters to abort expulsion. We postulated that during inflation with small volumes, the rectum did not adapt as in controls, but responded with contractions, which appear to be reflected in the multiple fluctuations in the tone limb. FI in these patients appears to be a consequence of the unstable or uninhibited rectum.
- Published
- 2001
14. Effect of Rectal Distension on Rectal Electromechanical Activity
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Olfat El-Sibai and Ahmed Shafik
- Subjects
Male ,Contraction (grammar) ,Mongrel dogs ,business.industry ,Rectum ,Action Potentials ,Longitudinal muscle ,Anatomy ,Rectal serosa ,Catheterization ,Dogs ,medicine.anatomical_structure ,Biological Clocks ,Circular muscle ,Pressure ,medicine ,Animals ,Abdomen ,Female ,Surgery ,Rectal distension ,business ,Constipation - Abstract
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.
- Published
- 2001
15. Suppression of Uninhibited Rectal Detrusor by Functional Magnetic Stimulation of Sacral Root
- Author
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Ahmed Shafik
- Subjects
Adult ,Male ,medicine.medical_specialty ,Cord ,medicine.medical_treatment ,Urology ,Rectum ,Stimulation ,Hyperreflexia ,Transducers, Pressure ,medicine ,Humans ,Paralysis ,Fecal incontinence ,Saline ,Spinal cord injury ,Spinal Cord Injuries ,Reflex, Abnormal ,business.industry ,Neural Inhibition ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Anesthesia ,Defecation ,Female ,Neurology (clinical) ,medicine.symptom ,Spinal Nerve Roots ,business ,Fecal Incontinence - Abstract
To demonstrate the effect of sacral magnetic stimulation (MS) on the uninhibited rectal detrusor aiming at suppression of unstable rectal contractions.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.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.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.
- Published
- 2000
16. Study of the Effect of Colonic Mass Movements on the Rectosigmoid Junction With Evidence of Colo-Rectosigmoid Junction Reflex
- Author
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Ahmed Shafik
- Subjects
Adult ,Male ,medicine.medical_specialty ,Colon ,Colonic mass ,Rectum ,Distension ,Pressure response ,Gastroenterology ,Descending colon ,Internal medicine ,Reflex ,medicine ,Humans ,Anesthetics, Local ,Defecation ,business.industry ,Lidocaine ,Sigmoid colon ,Middle Aged ,Rectosigmoid junction ,digestive system diseases ,medicine.anatomical_structure ,Female ,Surgery ,Gastrointestinal Motility ,business - Abstract
Mass movements of the left-sided colon bring the colonic material contained in it to the sigmoid colon. The cause why the colonic contents do not pass directly to the rectum but stop short of the rectosigmoid junction (RSJ) was studied. The study comprised 10 healthy volunteers (mean age 39.2 +/- 10.2 years; 8 men, 2 women). A condomended tube was introduced into the descending colon (DC) per anum. The pressure response of the DC, sigmoid colon (SC), and RSJ to condom inflation with carbon dioxide (CO2) in increments of 10 ml was recorded by means of a three-channel microtip catheter. The responses were registered upon inflation of the upper, middle, and lower third of the DC. The test was repeated after individual anesthetization of the descending colon and the RSJ on separate days. Colonic distension with 10 and 20 ml CO2 produced no significant pressure changes in the DC, SC, and RSJ (p.05); 30 ml distension effected a pressure rise in both the DC (p.01) and RSJ (p.05), but no change in the SC pressure (p.05); and 40, 50, and 60 ml distension produced pressure changes similar to those obtained with 30 ml distension. The RSJ pressure responded to distension of the saline-injected but not of the anesthetized DC. Thus, the RSJ response to colonic distension affirms the hypothesis of the possible involvement of a reflex, which we term colo-RSJ reflex. This reflex seems to regulate the passage of stools from the colon to the rectum. Further studies are required to investigate its role in the diagnosis of defecation disorders.
- Published
- 2000
17. Cholecysto-Sphincter Inhibitory Reflex: Identification of a Reflex and Its Role in Bile Flow in a Canine Model
- Author
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Ahmed Shafik
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,Vagotomy ,Distension ,Gastroenterology ,Catheterization ,Dogs ,Internal medicine ,Reflex ,Sphincter of Oddi ,Pressure ,Animals ,Bile ,Medicine ,Common Bile Duct ,Common bile duct ,business.industry ,Gallbladder ,medicine.anatomical_structure ,Fluoroscopy ,Anesthesia ,Duodenum ,Sphincter ,Female ,Surgery ,business - Abstract
To study the effect of gallbladder (GB) distension on the sphincter of Oddi (SO), 9 mongrel dogs (mean weight 15.3+/-3.6 kg) were studied. Under anesthesia, the abdomen was opened and the GB and SO were exposed. A balloon-tipped catheter was introduced into the GB and a manometric catheter into the common bile duct so that its fluoroscopically controlled tip lay within the SO. The pressure response of the GB and SO to GB distension by the balloon without and with selective anesthetization of the GB and SO was recorded. The test was repeated in four vagotomized dogs. GB distension effected pressure rise within the GB and pressure drop within the SO. The GB pressure increased progressively as the distending volume increased, while the SO pressure drop was not affected. Selective anesthetization of the GB or the SO produced no SO pressure changes upon GB distension. The SO pressure response to GB distension after vagotomy was similar to that before vagotomy. The SO relaxation on GB contraction, being reproducible and abolished by selective anesthetization of either the SO or the GB, postulates a reflex relationship that we call the cholecysto-sphincter inhibitory reflex. This reflex seems to regulate the bile flow from the GB to the duodenum through the SO.
- Published
- 1998
18. Ureteric Profilometry: A Study of the Ureteric Pressure Profile in the Normal and Pathologic Ureter
- Author
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Ahmed Shafik
- Subjects
Adult ,Male ,medicine.medical_specialty ,Manometry ,Urology ,urologic and male genital diseases ,Ureter ,Pressure ,medicine ,Humans ,Pelvis ,Peristalsis ,Vesico-Ureteral Reflux ,Urinary bladder ,business.industry ,Anatomy ,Middle Aged ,Catheter ,medicine.anatomical_structure ,Nephrology ,Ureterovesical Junction ,Pressure amplitude ,Female ,business ,Renal pelvis ,Ureteral Obstruction - Abstract
The ureteric pressure profile in the normal and pathologic ureter was studied. A 3F ureteric catheter was introduced through the ureteric orifice up to the mid-renal pelvis, and was connected to a pressure transducer. The catheter was pulled down to the urinary bladder and during withdrawal the pressures in the renal pelvis, uretero-pelvic junction (UPJ), ureter, ureterovesical junction (UVJ) and urinary bladder were recorded. The normal ureteric pressure profile started with a peak rise at the UPJ followed by a drop and fluctuations representing the peristaltic waves, and ended with a peak rise at the UVJ. The strictured moderately dilated ureter showed peristaltic waves with irregular rhythm and pressure amplitude, a condition we call "ureteroarryhthmia". The hugely dilated ureter exhibited no waves, i.e. a "silent" profile. The refluxing ureter with normal caliber showed an ureteroarrhythmic pressure profile, while the dilated ureter exhibited either a ureteroarrhythmic or a silent pattern. The study could define a characteristic profilometric pattern for the normal ureter. Two pathologic patterns could be identified: ureteroarrhythmic and silent. Ureteric pressure profilometry is suggested acts as a diagnostic tool in the various pathologic conditions of the ureter.
- Published
- 1998
19. Effect of Different Types of Textiles on Male Sexual Activity
- Author
-
Ahmed Shafik
- Subjects
Male ,medicine.medical_specialty ,Textile ,Ejaculation ,Polyesters ,Sexual Behavior ,Static Electricity ,Clothing ,Endocrinology ,Animal science ,medicine ,Human sexual activity ,Animals ,Humans ,Gossypium ,business.industry ,Penile Erection ,Textiles ,Wool ,Surgery ,medicine.anatomical_structure ,Sexual behavior ,Vagina ,business ,Sexual function ,Penis - Abstract
The effect of different types of textile underpants on sexual activity was studied in 50 men. All the subjects were potent and sexually active. They were divided into 5 equal groups: 4 test and 1 control. Each of the 4 test groups were dressed in one type of textile underpants made of either 100% polyester, 50/50% polyester/cotton mix, 100% cotton, or 100% wool. Sexual behavior was assessed before and after 6 and 12 months of wearing the pants, and 6 months after their removal. Behavioral response was rated as potent if the subject's penis became erect, entered the vagina, and ejaculated. The rate of potent intromission (I) to mounts (M) (I/M ratio) was determined. The electrostatic potentials (EP) generated on the penis and scrotum were measured by an electrostatic kilovoltmeter. The I/M ratio at 6 and 12 months of wearing the polyester and polyester/cotton mix pants was significantly reduced compared to the pretest levels and the controls (p < .001). The reduction was more manifest in the pure polyester than in the polyester/cotton mix group, and at the 12-month than at the 6-month examination. The I/M ratio of the cotton and wool groups showed insignificant changes during the study period. Six months after removal of the underpants, the I/M ratio had returned to the pretest levels in the two groups that had worn polyester-containing pants. The polyester-containing pants generated EP, which may induce electrostatic fields in the intrapenile structures and could explain the diminished sexual activity. The cotton and wool textiles did not generate EP. Thus, polyester underpants could have an injurious effect on human sexual activity.
- Published
- 1996
20. Cervico‐motor reflex: Description of the reflex and role in sexual acts
- Author
-
Ahmed Shafik
- Subjects
Sociology and Political Science ,business.industry ,Mean age ,Stimulation ,Anatomy ,Cervical stimulation ,Gender Studies ,medicine.anatomical_structure ,Levator ani ,History and Philosophy of Science ,Vaginal pressure ,Anesthesia ,medicine ,Vagina ,Reflex ,business ,Cervix ,General Psychology - Abstract
A recently identified reflex, termed the “cervico‐motor reflex,” was studied in 15 healthy women (mean age 36.6 years). The response of levator ani (LA) and puborectalis (PR) muscles to electrical and mechanical stimulation of the cervix uteri (CU) was determined. One concentric needle electrode was inserted into the CU (stimulating), a second into the LA (recording), and a third into the PR (recording). The vaginal pressure was measured at rest and on cervical stimulation by balloon‐tipped catheters. Electrical stimulation of the CU led to a reduction in pressure in the upper portion of the vagina (p < .05) and an increase in pressure in the middle and lower portions (p < .001). Stimulation also caused an increase in the electromyographic (EMG) activity of the LA and PR muscles (p < .01). Mechanical stimulation induced the same effects but to a lesser degree. Stimulation of the anesthetized CU, LA, or PR did not evoke the response. The data suggested the presence of a reproducible reflex relationship bet...
- Published
- 1996
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