Electromyographic activity of the anterolateral abdominal wall muscles during the vesical filling and evacuation

The role of the anterolateral abdominal wall muscles [AAWMs] during the vesical filling and evacuation has not been sufficiently addressed in the literature. We have investigated the hypothesis that the AAWMs exhibit the increased electromyographic [EMG] activity on the vesical distension and contraction which presumably assists vesical evacuation. The effects of the vesical balloon distension on the vesical pressure [VP], vesical neck [VNP] pressures and the AAWMs' EMG activity were studied in 28 healthy volunteers aged 40.7 +/- 9.7 years [18 men, 10 women]. These effects were tested after the individual anesthetization of the bladder and AAWMs and after saline infiltration. The VP and the VNP showed a gradual increase upon the incremental vesical balloon distension which started at a distending volume of 120-140 ml. At a mean volume of 364.6 +/- 23.8 ml, the VP increased to a mean of 36.6 +/- 3.2 cmH2O, the VNP decreased to 18.4 +/- 2.4 cmH2O, and the AAWMs EMG registered a significant increase. This effect disappeared in the individual bladder and in the AAWMs' anesthetization. However, it did not disappear in the saline administration. The AAWMs appear to contract simultaneously with vesical contraction. This action presumably increases the IAP and it assists vesical contraction. The AAWMs contraction on vesical contraction seems to be mediated through a reflex which is called the 'vesico-abdominal wall reflex'. Further studies are required to investigate the role of this reflex in vesical disorders

The cavernoso-anal reflex: response of the anal sphincters to cavernosus muscles' stimulation / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To prove the hypothesis that cavernosus muscles' contraction during coitus affects the reflex contraction of anal sphincters.</p><p><b>METHODS</b>Electromyographic response of external and internal anal sphincters to ischiocavernosus and bulbocavernosus muscle stimulation was studied in 17 healthy volunteers (10 men, 7 women, mean aged 38.3+/-11.6 years). The test was repeated after individual anesthetization of anal sphincters and the two cavernosus muscles, and after using saline instead of lidocaine.</p><p><b>RESULTS</b>Upon stimulation of each of the two cavernosus muscles, external and internal anal sphincters recorded increased electromyographic activity. Anal sphincters did not respond to stimulation of the anesthetized cavernosus muscles nor did anesthetized anal sphincters respond to cavernosus muscles' stimulation. Saline infiltration did not affect anal sphincteric response to cavernosal muscles' stimulation.</p><p><b>CONCLUSION</b>Cavernosus muscles' contraction is suggested to evoke anal sphincteric contraction, which seems to be a reflex and mediated through the "Cavernoso-anal reflex". Anal sphincteric contraction during coitus presumably acts to close the anal canal to thwart flatus or fecal leak.</p>

Immunohistochemical identification of the pacemaker cajal cells in normal human colon

The Interstitial Cells of Cajal [ICC] are C-Kit immunoreactive cells in the gastrointestinal tract. They are suggested to have a role in the control of gut motility. The present study was aimed to identify the morphology and the pattern of distribution of the ICC in the different parts of the human colonic segments. This study included sixteen normal colonic specimens obtained from the safety margins of the surgically excised colonic carcinoma. The prepared colonic longitudinal sections -were subjected to: haematoxylin and eosin, Masson's trichrome stain and to C-Kit immunohistochemistry. Statistical analysis was performed on the obtained data through the use of Leica Owin software of the image analyzer computer system to evaluate the degrees of locations of ICC [area percent] in the different colonic segments. The results revealed the following: ICC were demonstrated either as groups or as sporadic cells. The groups of ICC were surrounded with concentric connective tissue cells. The sporadic cells were usually in close relation to blood vessels and to the circular smooth muscle layers. ICC were of different sizes and different shapes. Statistical analysis through the use of the image analyzer was performed on the data obtained after examination of ten fields from each colonic segment. The area and area percent of the stained ICC were recorded in relation to a standard measuring frames. The obtained results revealed that great numbers of ICC were present at the coeco-colonic junction. The ascending, transverse and descending colonic segments showed moderate number of ICC. The greatest numbers of ICC were recorded in the region of sigmoid colon. ICC were located in the level of myenteric plexus, between the circular and longitudinal smooth muscle layers or within the circular muscle layer itself as reported in the sigmoid colon. The obtained results were discussed from the fact that ICC are considered to be generators of spontaneous pacemaker activity in the smooth muscle layers of the colon. They mediate or transduce inputs from enteric motor nerves to the smooth muscle syncytium

ileocaecal valve in man: anatomical, radiological and endoscopic studies with special reference to its antireflux mechanism

The uncertainty regarding the physio-anatomy of the ileocaecal junction, and in particular the question whether it acts as a valve or a sphincter, stimulated us to perform anatomical, histological, radiological and endoscopic studies of this junction. A clear understanding of the anatomical structure of the ileocaecal junction may throw some light on its function. Anatomical and histological studies were performed on 18 cadavers [mean age 34.2 +/- 18.4 years] and radiological on 22 [mean age 42.3 +/- 14.2 years] and endoscopic on 10 [mean age 38.6 +/- 7.9 years] healthy volunteers. Histological sections were stained with Masson's trichrome. The ileocaecal junction was studied radiologically using the method of small bowel barium meal follow through. Endoscopic study was done under controlled air inflation using a videoendoscope. A nipple [17-19 mm long] with transversely lying stoma protruded from the posteromedial wall of the caecum and a fornix was found on either of its sides. The nipple stoma was surrounded by two lips: upper and lower. Lateral and medial suspensory frenula started at the lateral and medial angles of the stoma respectively and extended along the whole caecal circumference in 44.4% or to half the circumference in 50%. They were marked on the external aspect of the caecum by a groove. The covering mucosa of the nipple showed mild rugae while the lining mucosa was smooth. Histologically, the musculosa of the terminal ileum extended into the ileocaecal nipple. The nipple contained mainly circular musclar fibers surrounded by adipose connective tissue. Radiologically, the ileocaecal nipple appeared as filling defect in the barium - filled caecum. As barium filled the terminal iteum, the ileocaecal nipple became distended with barium and appeared as a hen's beak; the nipple stoma then opened evacuating its contents into the caecum. The cycle of ileal filling, nipple distension and nipple evacuation was repeated every 6.6 +/- 1.4 seconds. The above mentioned observations were identified and confirmed endoscopically. From the findings observed in the present work it could be concluded that the ileocaecal nipple is closed at rest and it opens upon terminal ileal contraction to deliver ileal contents to the caecum. It evacuates the barium periodically into the caecum. The structure of the ileocaecal nipple seems to be adapted to serve the function of caeco - ileal antireflux

caecocolonic junction and sphincter in man: morphological, radiological and endoscopic study

Histomorphological and morphometric studies were carried out in 15 cadavers, radiological study was performed in 20 and endoscopic study in 16 healthy volunteers. Longitudinal histological sections along the caecum, the caecocolonic junction and the ascending colon were stained with hematoxylin and eosin as well as Masson's trichrome. The morphometric study determined the thickness of the muscle layers of the caecum, the caecocolonic junction and the asending colon using image analyser computer equipment. The caecocolonic junction was also examined radiologically by the method of small bowel barium meal follow through as well as endoscopically by pancolonoscopy. A caecocolonic fold was identified at 22-31 mm distal to the ileocaecal valve. It extended along the gut circumference and was shelf-like and marked by a shallow groove on the external aspect of the colon. Microscopically, the caecocolonic fold consisted of mucosa, submucosa, muscularis externa and serosa, all of which were a continuation of those of the caecal wall. The circular muscle layer of this fold was thicker than that of each of the caecum and the ascending colon. Branching cells with ovoid nuclei representing probably interstitial cells of Cajal were identified in the muscularis externa. The morphometric study also showed that the circular muscle layer was very highly significantly thicker than that of the caecum or the ascending colon [p < 0.001 and p < 0.001, respectively] while the longitudinal muscle layer exhibited no significant difference [p > 0.05 and p > 0.05, respectively]. Radiological study demonstrated narrowing at the caecocolonic junction which decreased on caecal contraction and increased or closed on ascending colonic contraction. Endoscopically, the caecocolonic junction was narrow due to the presence of the caecocolonic fold and sphincter which exhibited spontaneous contractions. In conclusion, the present study suggests the presence of an anatomical sphincter at the caecocolonic junction as evidenced histomorphometrically, radiologically and endoscopically. The muscularis externa was significantly thicker than that of each of the caecum and the ascending colon. Spasmodic contractions of the caecocolonic fold were observed on endoscopic examination. Radiological study showed dilatation and narrowing of the caecocolonic junction on caecal and ascending colon contraction, respectively. Absence of colocaecal reflux on colonic contraction is probably due to contraction of the caecocolonic sphincter. The detection of cells similar to the interstitial cells of Cajal, in the caecocolonic fold, postulates the possible existence of a pacemaker in the caecocolonic fold; a point that needs further investigation