The muscle coat of the lower esophageal sphincter in patients with achalasia and hypertensive sphincter. An electron microscopic study

The muscle coat of the lower esophageal sphincter (LES) of seven patients with achalasia and three patients with a hypertensive sphincter has been studied with the electron microscope. In these pathological conditions the ultrastructural pictures differ both from normal and from one another. In achalasia, the LES muscle wall components (nerve endings, smooth muscle cells, interstitial cells of Cajal and connective tissue) are altered, but, while all the nerve endings and interstitial cells are affected, only a few smooth muscle cells are damaged. The severity of the alterations is more pronounced in the older patients. On the contrary, there is no damage of the muscle wall components in the hypertensive sphincter, whereas an increase in the cytoplasmic organelles (smooth endoplasmic reticulum and mitochondria) has been found in all interstitial cells and in some smooth muscle cells. Moreover, the ultrastructural picture of the hypertensive sphincter does not seem to change with patients' age. Since the LES components specifically altered in achalasia are the nerve endings and the interstitial cells of Cajal, they are regarded as principally responsible for the altered motility. On the contrary, the ultrastructural picture of the hypertensive sphincter suggests an enhancement of the activity of the activity of all the interstitial cells and of some smooth muscle cell; therefore, we consider the hyperfunction of these cells as the cause of this esophageal motor disorder.

Ultrastructural features and localization of the interstitial cells of Cajal in the smooth muscle coat of human esophagus

The ultrastructure of the smooth muscle coat of the human esophagus has been studied. Special attention has been given to the interstitial cells of Cajal (ICC). The ICC are present wherever the esophageal musculature contains smooth muscle cells, but the amount of ICC varies with the esophageal level: in fact, the ICC are abundant in the esophageal body, are even more numerous in the lower esophageal sphincter (LES) and very rare in the gastric (distal) portion of the LES. Both the muscle layers contain ICC and their location varies according to the muscular bundles. Some ICC are inside these muscular bundles, a few are found in their proximity and the majority are located at the periphery of the bundles. According to their location, the ICC differ from one another in the extent of smooth endoplasmic reticulum, number of thin cytoplasmic filaments, presence of cytoplasmic crystalline inclusions, development of cell lateral branches and aspect of the connective tissue envelope. A great density of nerve endings, containing different types of synaptic vesicles, are preferentially related to the ICC. The inter-relationships observed between ICC, between ICC and smooth muscle cells and between ICC and Schwann cells are discussed. A structural model of the muscular bundles organization in the human esophagus is proposed and the possible role played by the ICC in the motility of the human esophagus is discussed on the basis of these morphological findings and data reported in the literature.

Ultrastructural peculiarities of the inner portion of the circular layer of colon. I. Research in the human

The inner part of the circular layer of the human colon is made up of a special muscle layer, three to eight row thick. Wide areas of connective tissue are found inside this inner circular layer and between it and the outer part of the circular layer. The muscle cells of this innermost layer have several special features: numerous glycogen particles and caveolae, well-developed sarcoplasmic reticulum, and wide contact areas with each other. At the border zone with the tela submucosa, there is a fibrous lamella rich in collagen and elastic fibers, lined by an incomplete layer of circularly orientated fibroblast-like cells. A nerve plexus, rich in varicosities, is located between the two circular layers, and nerve fibers are sparsely located inside the fibrous lamella. Interstitial cells of Cajal were not recognized.

Usefulness of combined gastric and esophageal pH monitoring in detecting gastroesophageal alkaline and mixed reflux

96 patients with 'typical' symptoms of gastroesophageal reflux were studied by means of combined gastric and esophageal pH monitoring. The aim was to assess the incidence of 'alkaline' and 'mixed' gastroesophageal reflux episodes as well as 'acid' reflux and their reciprocal relationship with esophagitis. 'Alkaline' gastroesophageal reflux was defined whenever the pH in the esophagus rose above 7, but only when there was a simultaneous or immediately previous rise of gastric pH to similar alkaline values resulting from duodenogastric reflux. 'Mixed' gastroesophageal reflux was defined whenever the pH in the esophagus dropped to 5.5-4.5, but only when there was a simultaneous or immediately previous rise of gastric pH above 4 related to duodenogastric reflux. Our data suggest that 'alkaline' gastroesophageal reflux is a rare phenomenon while 'mixed' gastroesophageal reflux episodes are present in 21% of these patients. 87% of patients with mixed reflux had esophagitis. Until analytical studies of refluxed material are available to clarify its composition, combined gastric and esophageal pH monitoring seems a useful test to correctly interpret the 'alkaline' and 'mixed' gastroesophageal reflux.

The release and neosynthesis of glutamic acid are increased in experimental models of hepatic encephalopathy

The effects of ammonium ions on the release of glutamic acid from the rat cerebral cortex were measured in vivo using cortical cups and a multiple ion detection technique. The neosynthesis of this amino acid from glucose was also studied in two experimental models of hepatic encephalopathy: (1) rats receiving large amounts of ammonium acetate (i.p.) and (2) rats with a surgically constructed portocaval anastomosis. Intraperitoneal administration of 8 mmol/kg of ammonium acetate increased the cortical release of glutamic acid from 9.1 +/- 0.8 to 19 +/- 2 (nmol X cm-2 X min-1). Moreover, 20 min after ammonium acetate administration the rate of incorporation of 13C2, originating from [13C]glucose, into glutamic acid increased by 65%. In several brain areas of rats bearing a portocaval anastomosis and fed ad libitum for 4 weeks, the content of glutamic acid slightly increased and the rate of formation of [13C2]glutamate from [13C]glucose approximately doubled. These results indicate that ammonium ions increase the release and the formation of glutamic acid in the brain. The resulting increased concentration of this amino acid in the extracellular spaces may be one of the mechanisms of ammonia toxicity in vivo.

Some ultrastructural features of the muscular coat of human small intestine

The muscular coat of human small intestine is constituted by a 'special' layer, by the main component of the circular layer, by the region between the circular and the longitudinal layers and by the longitudinal layer. The 'special' layer is made up of the innermost 4-6 rows of muscle cells of the circular layer and is separated from the main component of the circular layer by a space in which an abundant connective tissue and numerous nerve fibers rich in nerve endings are located. Cells identified as interstitial cells of Cajal are located inside the 'special' layer, the space between it and the main component of the circular layer and in the region between the circular and the longitudinal layers. In this region small bundles of obliquely orientated muscle cells, apparently bridging the circular to the longitudinal layer, are found.

Anorectal physiology after anterior resection and pull-through operation

Sensory and motor investigations have been performed in normal subjects, in patients who had undergone low anterior resection of the rectum and in patients following Bacon-type pull-through operation. The electromechanical relationship has been clearly defined in the anal sphincter activity. The motor findings, the threshold for sensation and its quality in the patients following low anterior resection were similar to those of the controls. Following pull-through operation the anorectal inhibitory reflex is frequently replaced by a contraction of the sphincteric zone. But, sometimes, this reflex is preserved as well as a fine discriminatory sensation. These data suggest that at least some of the mechanisms of anal sphincter continence have been preserved even after complete excision of the rectum.

The endocrine pancreas of the rat following portacaval shunt

Four weeks after portacaval shunt the pancreatic islets of rats underwent pronounced morphological changes. A cells showed few organelles and had a large amount of secretory granules which often appeared to swell and fuse into one another. B and D cells on the contrary had well developed rough endoplasmic reticulum and Golgi complex, numerous immature granules and a few mature granules; the latter often underwent exocytosis. In the peripheral area of the islets possible preinsular cells were frequently observed. such cells and typical D cells were also found outside the islets in the walls of ductules lying near the islets. Such findings suggest a functional inhibition of A cells and an enhancement of the secretory activity of B and D cells. Moreover a differentiation of islet cells from ductular cells seems to occur. Such a process seems to lead to neogenesis of D and probably of PP cells. The experimental data reported here should be considered in view of their possible implications in clinical medicine.

Platelet monoamine oxidase and blood plasma benzylamine oxidase activity in cirrhotic patients

Plasma and platelet benzylamine oxidase activity was tested before and after portacaval shunt in patients with histologically-confirmed cirrhosis of the liver. The level of plasma benzylamine oxidase activity was always higher in cirrhotic patients than in control subjects and was unchanged by the surgical operation. Platelet benzylamine oxidase activity was lower in cirrhotic than in control patients before the surgical operation, and higher afterwards but it returned to the original value at 80 days after surgery.

Ileal mucosal morphology after total colectomy in man

The structure of human terminal ileum mucosa was studied both after total colectomy and conventional ileostomy and after total colectomy and ileo-rectal anastomosis. Villous height, gland depth, number of mitoses, relative density of goblet cells and types of mucins secreted were microscopically evaluated in ileal biopsy specimens from 24 patients a minimum 6 months after surgery. Subtotal villous atrophy with glandular hypertrophy was demonstrated after both surgical procedures. The degree of villous atrophy and glandular hypertrophy was not dependent either on the disease for which surgery was performed, nor on the duration of the post-surgical period. Villous atrophy and glandular hypertrophy appeared greater in ileo-rectal anastomosis specimens than in those from ileostomy. Goblet cell density did not seem to be affected by total colectomy. After surgery no changes in the types of mucins secreted were shown by the histochemical techniques employed. This light microscopical study did not provide any evidence of increase ileal absorptive surface after total colectomy.

[Preciseness of the ultrastructural order in the tunic of the small intestine]

The muscular cost of ileum of man was observed both at light and electron microscopes. Four muscular layers could be identified. The first layer appears as an innermost layer of circular muscle. The second layer is the circular one. The third layer occupies the region between circular and longitudinal muscle layers. The fourth layer is the longitudinal one. The structure of both circular and longitudinal layers is like that described for other mammals. The first and the third layers show a very special structure; moreover, interstitial cells of Cajal are found inside the first layer and in the connective tissue lying between the first and second layer. In the third layer two types of smooth muscle cells are present: one types shows a typical structure; the second type, which was never described before, is very peculiar and because of its similarity with interstitial cells of Cajal has been considered of the same nature. Nerve bundles are mainly concentrated between the first and second layers and in the region between circular and longitudinal layers (the third layer), where is localised the myenteric plexus. All these findings are discussed in an attempt to correlate the contractile activities of ileum of man with the structure of its muscular coat.

Anorectal reflex following sphincter-saving operations

The function of the anal sphincters following anterior resection of the rectum and Bacon type pull-through operation has been investigated. Our data have shown a significant decrease in the anal resting pressure after pull-through excision indicating an impairment in the sphincter function. Nevertheless the sphincter response induced by stretch receptor stimulation can maintain continence.

Function of the anal sphincters following pull-through operations without anal eversion

It has been investigated the function of the anal sphincters following Bacon type pull-through operation. Our data have shown a significant decrease of the anal resting pressure after pull-through excision signifying an impairment in the internal sphincter function. But the tonic external sphincter contraction induced by stimulation can maintain continence.

Function of the anal sphincters following anterior resections of rectum

The purpose of the present work is to evaluate the function of the anal sphincter following anterior resections of the rectum. Our data have shown that the anorectal reflex did not depend on the presence of the rectal mucosa. The external anal sphincter contraction involves a reflex which is initiated by stretch receptors in the levator ani muscle. The internal anal sphincter relaxation is likely a local reflex involving nerve pathways not yet completely defined.

Rectoanal reflex in healthy subject

The present work was performed in order to examine the rectoanal reflex in healthy subject. Our findings suggest that the fecal continence is sustained by both the anal sphincters. The maximal anal pressure at rest is governed by activity of the internal sphincter while the external anal sphincter promptly contracts when the rectum is distended.

Platelet monoamine oxidase, plasma benzylamine oxidase and liver mixed function oxidase in cirrhotic patients

Because it has been suggested that an accumulation of false neurochemical transmitters plays a part in the cardiovascular and neurological complications of cirrhosis it appeared worthwhile to study the level of monoamine oxidase in the liver and platelets of cirrhotic patients. In fact a decrease of such activities might explain the increase of false neurotransmitters observed in cirrhotic patients. Other enzyme were also tested: the plasma benzylamine oxidase activity and the liver mixed function oxidases. 13 cases of severe cirrhosis (B, C according to Child classification) and 10 cases of less severe cirrhosis (A according to Child classification) were studied in comparison to patients affected by cholelithiasis. A defect in the level of monoamine oxidase activity of platelets and liver was observed in some cirrhotic patients together with a decrease of the level of the liver mixed function oxidases.