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sphincter muscle [keywords]
- Functional and anatomical differences between continent and incontinent men post radical prostatectomy on urodynamics and 3T MRI: A pilot study. [JOURNAL ARTICLE]
- Neurourol Urodyn 2014 Apr 21.
There are competing hypotheses about the etiology of post prostatectomy incontinence (PPI). The purpose of this study was to determine the anatomical and functional differences between men with and without PPI.Case-control study of continent and incontinent men after radical prostatectomy who underwent functional and anatomic studies with urodynamics and 3.0 Tesla MRI. All men were at least 12 months post prostatectomy and none had a history of pelvic radiation or any prior surgery for incontinence.Baseline demographics, surgical approach, and pathology were similar between incontinent (cases) (n = 14) and continent (controls) (n = 12) men. Among the cases, the average 24 hr pad weight was 400.0 ± 176.9 g with a mean of 2.4 ± 0.7 pads per day. Urethral pressure profiles at rest did not significantly differ between groups; however, with a Kegel maneuver the rise in urethral pressure was 2.6 fold higher in controls. On MRI, the urethral length was 31-35% shorter and the bladder neck was 28.9° more funneled in cases. There were no differences in levator ani muscle size between groups. There was distortion of the sphincter area in 85.7% of cases and in 16.7% of controls (P = 0.001).Men with PPI were not able to increase urethral pressure with a Kegel maneuver despite similar resting urethral pressure profiles. Additionally, incontinent men had shorter urethras and were more likely to have distortion of the sphincter area. All suggesting that the sphincter in men with PPI is both diminutive and poorly functional. Neurourol. Urodynam. © 2014 Wiley Periodicals, Inc.
- Aging-Associated Oxidative Stress Leads to Decrease in IAS Tone via RhoA/ROCK Downregulation. [JOURNAL ARTICLE]
- Am J Physiol Gastrointest Liver Physiol 2014 Apr 17.
Background & Aims: Internal anal sphincter (IAS) tone plays an important role in rectoanal incontinence (RI). The IAS tone may be compromised during aging leading to RI in certain patients. Herein, we examined the influence of oxidative stress in the aging-associated decrease in the IAS tone (AADI). Methods: Using two different age groups of adult (4- 6 months (Ad)) vs. aging (24 to 30 months (Ag)) rats, we determined the effect of oxidative stress on IAS tone, and the regulatory RhoA/ROCK signal transduction cascade. We determined the effect of an oxidative stress inducer LY83583 (that produces superoxide anions or O2(-)), on the basal and stimulated IAS tone, before and after O2(-) scavenger superoxide dismutase (SOD) using intact smooth muscle (SM) strips and SMCs. Results: Data showed that AADI was associated with decrease in RhoA/ROCK expression at the transcriptional and translational levels. Oxidative stress with LY83583-mediated decrease in the IAS tone and relaxation of the IAS SMCs were associated with the decrease in RhoA/ROCK signal transduction, reversible by SOD. In addition, LY83583 caused a significant decrease in the IAS contraction produced by the RhoA activator, and a known RhoA/ROCK agonist U46619, also reversible by SOD. The inhibitory effects of LY83583 and ROCK inhibitor Y27632 on U46619-induced increase in the IAS tone were similar. Conclusion: An increase in oxidative stress plays an important role in the AADI in the elderly, and may be one of the underlying mechanisms for the RI in certain aging patients.
- Anorectal conditions: fecal incontinence. [Journal Article]
- FP Essent 2014 Apr.:35-47.
Although fecal incontinence occurs in all age groups, it is more common among older adults, especially nursing home residents, and it is more common among women than men. It often is associated with urinary incontinence. Etiologies are broadly categorized to include anatomic/physiologic changes due to trauma, surgery, vaginal deliveries, radiation, or disease states; neurologic disorders; drugs; and functional impairments. Evaluation is aimed at identifying etiologies, and scoring systems can be used to estimate severity and monitor outcomes. The first step in treatment is managing possible etiologies and implementing conservative measures, including increasing dietary fiber intake, using antidiarrheal drugs, removing fecal impactions, and using biofeedback. If these measures fail to control incontinence, further testing can characterize specific defects. Tests include endorectal ultrasound, anorectal manometry, and pudendal nerve terminal motor latency. After the defect is characterized, management options include injecting biocompatible material to bulk up a rectal sphincter with a defined defect, suture repair of sphincter defects, transfer of gracilis or gluteal muscle to create a new sphincter, implanting an artificial sphincter or neurostimulator, creating an ostomy through which retrograde enemas can be administered, and colostomy to prevent feces from reaching the rectum. Anal plugs are a last resort.
- The effects of tamsulosin and alfuzosin on iris morphology: an ultrasound biomicroscopic comparison. [JOURNAL ARTICLE]
- Cutan Ocul Toxicol 2014 Apr 14.
Abstract Context: It is well known that Alpha-1 adrenergic receptor antagonists affect the receptors in the prostate and also iris dilator muscle, leading to loss of iris muscle tone. Objective: To compare morphological alterations of iris secondary to tamsulosin and alfuzosin use. Participants: Patients included in the study were grouped as follows: 16 patients treated with tamsulosin (Group 1), 14 patients treated with alfuzosin (Group 2) and 18 untreated controls (Group 3). Materials and methods: All patients underwent ultrasound biomicroscopic and pupillometric examination. Iris thickness was measured at the dilator muscle region (DMR; measured at half of the distance between the scleral spur and the pupillary margin) and sphincter muscle region (SMR; Standardized at 0.75 mm from the pupillary margin). DMR/SMR was also calculated for each patient. Differences among groups were analysed. Main outcome measures were DMR, SMR, DMR/SMR and pupillary diameter. Results: Mean duration of treatments were 2.4 ± 0.96 years (1-4) and 2.3 ± 1.01 years (1-4) in Groups 1 and 2. Pupillary diameters were reduced in Groups 1-2 compared to Group 3 (p < 0.001, p < 0.001). The SMR was similar in Groups 1 and 2 (p: 0.114). These values were not significantly different from that of Group 3 (p: 0.196, p: 0.209). However, thickness in the DMR in Groups 1-2 were significantly lower than that of controls (Group 3) whereas there was no significant difference between Groups 1 and 2 (p: 0.041, p: 0.039 and 0.986, respectively). Mean DMR/SMR ratios were significantly lower in Groups 1-2 than that of Group 3 (p: 0.040 and p: 0.040, respectively). Conclusions: In patients using these medications, the iris seems to be thinner at the dilator muscle region, but preserving the sphincter muscle region.
- Substance P is essential for maintaining gut muscle contractility: a novel role for co-neurotransmission revealed by botulinum toxin. [JOURNAL ARTICLE]
- Am J Physiol Gastrointest Liver Physiol 2014 Apr 3.
Background & Aims: Substance P (SP) is commonly co-expressed with acetylcholine in enteric motor neurons and according to the classical paradigm, both these neurotransmitters excite smooth muscle via parallel pathways. We hypothesized that in addition, SP was responsible for maintaining the muscular responsiveness to acetylcholine (ACh). We tested this hypothesis by using botulinum toxin (BoNT/A), a known blocker of vesicular release of neurotransmitters including acetylcholine and neuropeptides. Methods: BoNT/A was injected into rat pyloric sphincter in different doses; as control we used boiled BoNT/A. At the desired time point, the rats were sacrificed and pyloric contractility was measured ex vivo in an organ bath and by measuring phosphorylation of myosin light chain 20 (MLC20). Results: BoNT/A (10 IU) significantly reduced the response of pyloric muscle to exogenous ACh, an effect that was accompanied by reduced MLC20 phopshorylation in the muscle. Both effects were reversed by exogenous SP. CP-96345, a NK1 receptor antagonist, blocked the ability of exogenous SP to reverse the cholinergic hyporesponsiveness as well as the reduction in MLC20 phosphorylation induced by BoNT/A. Conclusion: We have identified a novel role for SP as a co-neurotransmitter that appears to be important for the maintenance of muscular responsiveness to the principal excitatory neurotransmitter, acetylcholine. These results also provide new insight into the effects of botulinum toxin on the enteric nervous system and gastrointestinal smooth muscle.
- Pantoprazole decreases gastroesophageal muscle tone in newborn rats via rho-kinase inhibition. [JOURNAL ARTICLE]
- Am J Physiol Gastrointest Liver Physiol 2014 Apr 3.
Proton pump inhibitors reduce gastric acid secretion and are commonly utilized in the management of gastroesophageal reflux disease (GERD) across all ages. Yet a decrease in lower esophageal sphincter tone has been reported in vitro in rats through an unknown mechanism, however their effect on the gastroesophageal muscle tone early in life was never studied. Hypothesizing that proton pump inhibitors also reduce gastroesophageal muscle contraction in newborn and juvenile rats, we evaluated the in vitro effect of pantoprazole on gastric and lower esophageal sphincter muscle tissue. Electrical field stimulation (EFS) and carbachol-induced force were significantly (P<0.01) reduced in the presence of pantoprazole, whereas the drug had no effect on the neuromuscular-dependent relaxation. When administered in vivo, pantoprazole (9 mg/kg) significantly (P<0.01) reduced gastric emptying time at both ages. In order to ascertain the signal transduction pathway responsible for the reduction in muscle contraction, we evaluated the tissue rho-associated kinase 2 (ROCK-2) and CPI-17 activity. Pantoprazole reduced myosin light chain phosphatase MYPT-1, but not CPI-17 phosphorylation of gastric and lower esophageal sphincter tissue strongly suggesting that it is a ROCK-2 inhibitor. To the extent that these findings can be extrapolated to human neonates, the use of pantoprazole may impair gastric and lower sphincter muscle tone and thus paradoxically exacerbate esophageal reflux. Further studies addressing the effect of proton pump inhibitors on gastroesophageal muscle contraction are warranted to justify its therapeutic use in GERD.
- Nerves and fasciae in and around the paracolpium or paravaginal tissue: an immunohistochemical study using elderly donated cadavers. [Journal Article]
- Anat Cell Biol 2014 Mar; 47(1):44-54.
The paracolpium or paravaginal tissue is surrounded by the vaginal wall, the pubocervical fascia and the rectovaginal septum (Denonvilliers' fascia). To clarify the configuration of nerves and fasciae in and around the paracolpium, we examined histological sections of 10 elderly cadavers. The paracolpium contained the distal part of the pelvic autonomic nerve plexus and its branches: the cavernous nerve, the nerves to the urethra and the nerves to the internal anal sphincter (NIAS). The NIAS ran postero-inferiorly along the superior fascia of the levator ani muscle to reach the longitudinal muscle layer of the rectum. In two nulliparous and one multiparous women, the pubocervical fascia and the rectovaginal septum were distinct and connected with the superior fascia of the levator at the tendinous arch of the pelvic fasciae. In these three cadavers, the pelvic plexus and its distal branches were distributed almost evenly in the paracolpium and sandwiched by the pubocervical and Denonvilliers' fasciae. By contrast, in five multiparous women, these nerves were divided into the anterosuperior group (bladder detrusor nerves) and the postero-inferior group (NIAS, cavernous and urethral nerves) by the well-developed venous plexus in combination with the fragmented or unclear fasciae. Although the small number of specimens was a major limitation of this study, we hypothesized that, in combination with destruction of the basic fascial architecture due to vaginal delivery and aging, the pelvic plexus is likely to change from a sheet-like configuration to several bundles.
- Nerves supplying the internal anal sphincter: an immunohistochemical study using donated elderly cadavers. [JOURNAL ARTICLE]
- Surg Radiol Anat 2014 Apr 2.
Nerves serving the internal anal sphincter (NIAS) have been described as the lower rectal branches of the pelvic autonomic nerve plexus. However, their topographical anatomy and fiber components have remained unclear.Using histological sections from ten elderly donated cadavers, we investigated the topographical anatomy and composite fibers of the NIAS using immunohistochemistry for S100 protein, neuronal nitric oxide synthase (nNOS), vasoactive intestinal polypeptide (VIP) and tyrosine hydroxylase (TH).At the 2-3 o'clock position in the lower rectum, the NIAS originated from nerves at the posterolateral corner of the prostate in males or in the lower paracolpium in females. The nerves ran inferiorly along the internal aspect of the levator ani muscle, and joined branches of the myenteric plexus at a level slightly above the epithelial junction. The NIAS contained both nNOS-positive parasympathetic nerve fibers and TH-positive sympathetic fibers, but VIP-positive fibers were few in number.The origin of the NIAS at the posterolateral corner of the prostate as well as in the lower paracolpium might be sacrificed or damaged during radical prostatectomy or tension-free vaginal tape insertion. Low anterior resection of rectal cancer will most likely render damage to the NIAS because of its intersphincteric course. Although the nerve composition of the NIAS is characterized by a higher proportion of sympathetic nerve fibers than the myenteric plexus in the large intestine, their role is unclear. However, evaluation of sphincteric function after surgery would appear to be difficult because of the complex control mechanism independent of nerve supply.
- Effect of vaginal delivery on the external anal sphincter muscle innervation pattern evaluated by multichannel surface EMG: results of the multicentre study TASI-2. [JOURNAL ARTICLE]
- Int Urogynecol J 2014 Apr 1.
A correlation exists between external anal sphincter (EAS) damage during birth and the subsequent development of fecal incontinence. This study evaluated the effect of delivery-related trauma on EAS innervation by means of intra-anal EMG performed with a rectal probe with 16 silver electrodes equally spaced along the circumference, before and after delivery.Pre-partum EMG measurements were performed on 511 women, by nine clinical partners from five European countries at the 28th to 34th gestational weeks and the 6th to 8th post-delivery weeks; 331 women returned, after delivery, for the second test. The innervation zones (IZ) of EAS single motor units were identified by means of an EMG decomposition algorithm.The subjects were divided into four groups according to the delivery mode (Caesarean, vaginal with no evident damage, spontaneous lacerations and episiotomies). The number of IZs before and after delivery was compared. In the 82 women who underwent right mediolateral episiotomy, a statistically significant reduction of IZs was observed, after delivery, in the right ventral quadrant of the EAS (side of the episiotomy). Women who had Caesarean section, spontaneous lacerations or lack of evident damage did not present any significant change in the innervation pattern.Right episiotomy reduces the number of IZs on the right-ventral side of the EAS. The fast and reliable test proposed indicates the sphincter innervation pattern before delivery and helps obstetricians to evaluate the risks and to choose the preferred side of the episiotomy, if deemed necessary at the time of delivery.
- [Clinical application of magnetic resonance imaging in congenital anorectal malformation]. [English Abstract, Journal Article]
- Zhonghua Er Ke Za Zhi 2014 Jan; 52(1):41-5.
To investigate the clinical value of MRI examination in congenital anorectal malformation (CARM).Forty-four cases with operatively proved anorectal malformation from May 2008 to May 2012 in the authors' hospital were reviewed. Of the 44 cases, 25 were males and 19 females, their age ranged from 1 day to 2 years. MRI was performed in all patients.Of all 44 cases, 15 cases had high imperforate anus (34%), rectum blind end were above PC line, the distance of rectum blind end and anus nest was (29.12 ± 2.35) mm; 8 cases had median imperforate anus (18%), rectum blind ends were near PC line, the distance of rectum blind end and anus nest was (18.98 ± 2.21) mm; 21 cases had low imperforate anus (48%), rectum blind ends were below PC line, the distance of rectum blind end and anus nest was (7.54 ± 1.08) mm. Twenty-five cases with fistula in 44 cases were confirmed by rectal angiography and surgery, accounting for 57%. In 13 cases with fistula, the lesion could be clearly demonstrated on MRI, in the remaining 12 cases with fistula, the lesion could not be visualized clearly or no image development occurred on MRI. Of all 44 cases, 1 case had tethered cord with filum terminale lipoma, 1 case had tethered cord, 2 cases had syringomyelia, 1 case had right kidney agenesis, 1 case had hydrocele. In 44 cases of multi-planar MRI imaging could clearly show the perianal muscles developmental situation, 36 cases had perianal muscles dysplasia, amd showed levator ani muscle, puborectalis and anal sphincter asymmetry, muscle belly slim.MRI examination has a high clinical value in CARM diagnosis, can help accurately judge the anal atresia type, display the presence and running of most of the fistula, and diagnose perianal muscle development and other systems malformations, finally provide a reliable diagnostic basis for surgical program and prognostic assessment.