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Anal Sphincter Muscles (anal + sphincter_muscle)
Selected AbstractsEndothelin A receptors mediate relaxation of guinea pig internal anal sphincter through cGMP pathwayNEUROGASTROENTEROLOGY & MOTILITY, Issue 9 2010S.-c. Huang Abstract Background, Endothelin (ET) modulates motility of the internal anal sphincter through unclear receptor subtypes. Methods, We measured relaxation of guinea pig internal anal sphincter strips caused by ET-related peptides and binding of 125I-ET-1 to cell membranes prepared from the internal anal sphincter muscle. Visualization of 125I-ET-1 binding sites in tissue was performed by autoradiography. Key Results , In the guinea pig internal anal sphincter, ET-1 caused a marked relaxation insensitive to tetrodotoxin, atropine, or ,-conotoxin GVIA. ET-2 was as potent as ET-1. ET-3 caused a mild relaxation. The relative potencies for ETs to cause relaxation were ET-1 = ET-2 > ET-3. The ET-1-induced relaxation was inhibited by BQ-123, an ETA antagonist, but not by BQ-788, an ETB antagonist. These indicate that ETA receptors mediate the relaxation. The relaxant response of ET-1 was attenuated by LY 83583, KT 5823, Rp-8CPT-cGMPS, tetraethyl ammonium, 4-aminopyridine and N(omega)-nitro-l-arginine, but not significantly affected by NG -nitro-l-arginine methyl ester, NG -methyl-l-arginine, charybdotoxin, apamin, KT 5720, and Rp-cAMPS. These suggest the involvement of cyclic guanosine 3,,5,-cyclic monophosphate (cGMP), and potassium channels. Autoradiography localized 125I-ET-1 binding to the internal anal sphincter. Binding of 125I-ET-1 to the cell membranes prepared from the internal anal sphincter revealed the presence of two subtypes of ET receptors, ETA and ETB receptors. Conclusions & Inferences, Taken together, these results demonstrate that ETA receptors mediate relaxation of guinea pig internal anal sphincter through the cGMP pathway. [source] Sphincter electromyography and multiple system atrophyMUSCLE AND NERVE, Issue 1 2003Frederick Nahm MD Abstract Electromyographic studies of the sphincter in patients with multiple system atrophy have shown increased duration and polyphasia of motor unit potentials. These electrophysiological markers have been used to argue for the selective degeneration of sacral motor neurons in Onuf's nucleus in patients with multiple system atrophy. Studies comparing sphincter electromyographic changes in patients with multiple system atrophy and Parkinson's disease have shown significant differences between these two patient populations. Despite the controversy surrounding this claim, recent studies using quantitative electromyographic techniques support the view that reinnervation of the anal sphincter muscles may be a useful diagnostic marker for distinguishing multiple system atrophy from Parkinson's disease. A critical review of these data is needed to assess the validity and reliability of electromyographic changes in multiple system atrophy. © 2003 Wiley Periodicals, Inc. Muscle Nerve 28: 18,26, 2003 [source] Risk factors for third degree perineal ruptures during deliveryBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 4 2001J.W. de Leeuw Objective To determine risk factors for the occurrence of third degree perineal tears during vaginal delivery. Design A population-based observational study. Population All 284,783 vaginal deliveries in 1994 and 1995 recorded in the Dutch National Obstetric Database were included in the study. Methods Third degree perineal rupture was defined as any rupture involving the anal sphincter muscles. Logistic regression analysis was used to assess risk factors. Main outcome measures An overall rate of third degree perineal ruptures of 1.94% was found. High fetal birthweight, long duration of the second stage of delivery and primiparity were associated with an elevated risk of anal sphincter damage. Mediolateral episiotomy appeared to protect strongly against damage to the anal sphincter complex during delivery (OR: 0.21, 95% CI: 0.20,0.23). All types of assisted vaginal delivery were associated with third degree perineal ruptures, with forceps delivery (OR: 3.33, 95%-CI: 2.97,3.74) carrying the largest risk of all assisted vaginal deliveries. Use of forceps combined with other types of assisted vaginal delivery appeared to increase the risk even further. Conclusions Mediolateral episiotomy protects strongly against the occurrence of third degree perineal ruptures and may thus serve as a primary method of prevention of faecal incontinence. Forceps delivery is a stronger risk factor for third degree perineal tears than vacuum extraction. If the obstetric situation permits use of either instrument, the vacuum extractor should be the instrument of choice with respect to the prevention of faecal incontinence. [source] Assessment of sonographic quality of anal sphincter muscles in patients with faecal incontinenceCOLORECTAL DISEASE, Issue 9 2009I. Pinsk Abstract Objective, The main application of endoanal ultrasonography (US) in evaluation of faecal incontinence is to identify surgically correctable sphincter defects. The aim of our study was to determine whether qualitative changes in echogenicity and in uniformity of internal (IAS) and external (EAS) anal sphincter muscles detected on endoanal US correlate with other anal laboratory tests and modified Wexner faecal incontinence functional score. Method, Records on 99 patients having complete information on anorectal manometry, faecal incontinence scoring and available endoanal US imaging of the anal sphincters were included in statistical analysis. Anatomic appearance and changes in echogenicity of the anal sphincter muscles were recorded according to the proposed scoring system. Endoanal US defect and quality component scores for IAS and EAS as well as the total score were correlated with anal laboratory tests and incontinence score using Spearman's correlations test. Results, There was a trend for correlation between IAS quality score and incontinence score (P = 0.06), but no correlation for IAS defect score. EAS defect score had a significant negative correlation with maximum squeeze pressure (MSP) (P = 0.031). Distal EAS quality score had a significant correlation with incontinence score (P = 0.002). EAS total score correlated with MSP (P = 0.02) and incontinence score (P = 0.006). Endoanal US total score was significantly correlated with incontinence score (P = 0.006), maximal resting (MRP) (P = 0.035) and MSP (P = 0.045) and high pressure anal canal zone length (P = 0.03). Conclusion, Sonographic morphology of anal sphincter muscles correlates with anal laboratory tests and functional incontinence score. Qualitative ultrasound scoring instrument may improve evaluation of patients with faecal incontinence. [source] Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: a 10-year cohort analysisCOLORECTAL DISEASE, Issue 3 2008T. C. Dudding Abstract Objective, Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence. We aimed to identify specific factors that could predict the outcome of temporary and permanent stimulation. Method, A cohort analysis was performed to identify potential predictive factors in 81 patients who underwent temporary SNS at a single institution over a 10-year period (June 1996 to June 2006). Data were obtained from prospectively collected patient symptom diaries and quality of life questionnaires, operation reports, anorectal physiological studies, endoanal ultrasound images and radiology of lead placement. Results, Clinical outcome of temporary screening was not affected by patient gender, age, body mass index, severity or length of symptoms. The need for a repeated temporary procedure was associated with subsequent failure during screening (P = 0.008). A low threshold to obtain a motor response during temporary lead insertion was associated with improved outcome (P = 0.048). Evidence of anal sphincter trauma was associated with a greater risk of failure (P = 0.040). However, there was no difference in medium-term outcome between patients with external anal sphincter (EAS) defects and patients with intact anal sphincter muscles. Conclusion, Variables have been identified that help to predict the outcome of SNS. The presence of an EAS defect should not preclude treatment. [source] Anorectal three-dimensional endosonography and anal manometry in assessing anterior rectocele in women: a new pathogenesis concept and the basic surgical principleCOLORECTAL DISEASE, Issue 1 2007F. S. P. Regadas Abstract Objective, The anatomy of the anal canal, the anorectal junction and the lower rectum was studied with 3-D ultrasound. Method, Seventeen women with normal bowel transit, without rectocele (group 1) and 17 female patients with a large anterior rectocele (group 2) were examined with a B&K Medical Rawk®. Mean age was 44.5 and 51.6 years respectively. In group 1, one (5.8%) patient was nuliparous, five (29.4%) had a caesarian section, 11 (64.7%) had a vaginal delivery while in group 2, two (11.7%) patients were nuliparous, four (23.5%) had a caesarian section and 11 (64.7%) had a vaginal delivery. Images were reconstructed in midline longitudinal (ML) and transverse (T) planes. The external (EAS) and internal (IAS) anal sphincters were measured in both projections. Results, In the ML plane, the EAS length was longer in group 1 (1.94 cm vs 1.61 cm, P < 0.05), the gap length was shorter (1.54 cm vs 1.0 cm P < 0.01) and the wall thickness was shorter in group 2 (0.40 cm vs 0.50 cm P < 0.01). The IAS (0.18 cm vs 0.23 cm P < 0.01) and EAS thickness (0.68 cm vs 0.77 cm, P < 0.05) (left lateral of the posterior quadrant) was greater in group 2. In group 1, the anterior upper anal canal wall in normal females was an extension of the rectal wall and the circular muscle was thicker in the mid-anal canal to form the IAS. In group 2, however, the wall layers were not identified and the IAS was found to be more distal. The differences were not statistically significant in the anal canal resting and squeeze pressures in the two groups. Conclusion, Obstetric trauma does not seem to play any role in rectocele pathogenesis because the anal sphincter muscles are anatomically and functionally normal and rectocele is also present in nuliparous and in women with caesarian sections. It seems that it is associated with the absence of EAS and thinner IAS in the anterior upper anal canal. Herniation starts at the upper anal canal extending to the lower rectum in high or large rectoceles and maybe produced by rectal intussusception because of excessive and prolonged straining during defecation. In fact, the denomination ,rectocele' should be changed to ,anorectocele'. [source] | ||||||||||