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Biomedical subjects

C Cortesini

Publications and source records attributed to C Cortesini.

At least 55 records · Page 3Linked to original sources
PubMed1988

The origin and differentiation of adrenocortical cells in rats with portacaval shunt. A structural and ultrastructural study.

The formation of adrenocortical cells in the rat was studied by light and electron microscopy in an experimental model, namely portacaval shunt (P.C.S.), in which strong hyperplasia of the cells of the capsular region occurs. The results of this study indicate that in physiological conditions at the level of the adrenal gland capsule some epithelial cells, morphologically distinguishable as dark and clear cells, are found which can be interpreted as precursors of adrenocortical cells. From observations of intermediate forms between capsular precursors and mature adrenocortical cells, which are found in high numbers following P.C.S., it seems that the dark precursors give rise to cells of the zona glomerulosa and the clear precursors evolve into cells of the zona intermedia, which are to be considered as the starting point for the formation of cells of the zona fasciculata.

Adrenal Cortex↗
PubMed1986

Content of quinolinic acid and of other tryptophan metabolites increases in brain regions of rats used as experimental models of hepatic encephalopathy.

The content of the tryptophan metabolites quinolinic acid (QUIN), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) was measured in various brain areas of rats bearing a portocaval anastomosis (PCA) for 4 weeks, using mass fragmentography or HPLC. In these animals, the content of the excitotoxic compound QUIN increased by 75% in the cortex and 125% in the cerebellum. The content of 5-HT increased by 27% in the brainstem. No changes occurred in other brain areas. On the other hand, the content of 5-HIAA increased by 66% in the cortex, 65% in the caudate, 64% in the hippocampus, 120% in the diencephalon, and 185% in the brainstem. Probenecid administration caused a larger increase of 5-HIAA accumulation in various brain areas of PCA-bearing rats than in those of sham-operated controls. The cortical content of QUIN and 5-HIAA increased after administration of ammonium acetate (7 mmol/kg), whereas an equimolar amount of sodium acetate was inactive. These results confirm that profound changes in the disposition of tryptophan occur in the brains of experimental animals used as models of hepatic encephalopathy. Furthermore, this study adds the excitotoxic compound QUIN to the list of molecules possibly involved in the pathogenesis of this brain disorder.

Acetates↗
PubMed1986

Ultrastructure of striated muscle fibers in the middle third of the human esophagus.

Striated muscle fibers and their spatial relationship to smooth muscle cells have been studied in the middle third of human esophagus. Biopsies were obtained from 3 patients during surgery. In both the circular and longitudinal layers, the muscle coat of this transition zone was composed of fascicles of uniform dimension (100-200 microns of diameter); some of these bundles were made up of striated muscle fibers, others were pure bundles of smooth muscle cells and some were of the mixed type. Striated muscle fibers represented three different types, which were considered as intermediate, with certain structural features characteristic of the fast fiber type. Of these, the most frequently-found fibers were most similar to the fast fiber type. Satellite cells were numerous; in mixed fascicles they were gradually replaced by smooth muscle cells. The gap between striated muscle fiber and smooth muscle cells was more than 200 nm wide. It contained the respective basal laminae and a delicate layer of amorphous connective tissue. No specialized junctions were formed between consecutive striated muscle fibers, or between striated muscle fibers and smooth muscle cells. Interstitial cells of Cajal were never situated as close to striated muscle fibers as to smooth muscle cells.

Esophagus↗
PubMed1985

Relationship between mixed acid-alkaline gastroesophageal reflux and esophagitis.

The severity of reflux esophagitis is related to the potency of refluxed material and the duration of its contact with the esophageal mucosa. The occurrence of esophagitis in patients with gastric hyposecretion or even with achlorhydria has focused attention on nonacid gastroduodenal contents. Until analytical studies of refluxed material are available to clarify its composition, the 24-hour combined gastric and esophageal pH monitoring can be used for detecting gastroesophageal reflux and for trying to analyze the composition of the refluxate. The first problem of this investigation was to examine whether the mixed acid-alkaline reflux, defined by pH monitoring, represented reflux of duodenal content; the second to study if there was a correlation between this type of gastroesophageal reflux and esophagitis. Unequivocal grade II and III esophagitis were considered. Our data suggest that the mixed acid-alkaline gastroesophageal reflux represents reflux of duodenal contents into the stomach and successively into the esophagus. The higher incidence of endoscopic-proven esophagitis in patients with mixed acid-alkaline gastroesophageal reflux in comparison to patients with acid gastroesophageal reflux supports the concept that biliary and pancreatic secretions may be a contributory factor in esophageal injury.

Acids↗
PubMed1985

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.

Aged↗
PubMed1985

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.

Adolescent↗
PubMed1984

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.

Esophagitis, Peptic↗
PubMed1984

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.

Adult↗
PubMed1983

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.

Acetates↗
PubMed1983

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.

Anal Canal↗
PubMed1983

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.

Adult↗
PubMed1982

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.

Benzylamine Oxidase↗