Digestive enzyme compartmentalization and recycling and sites of absorption and secretion along the midgut of Dermestes maculatus (Coleoptera) larvae.

Bostrichiformia is the less known major series of Coleoptera regarding digestive physiology. The midgut of Dermestes maculatus has a cylindrical ventriculus with anterior caeca. There is no cell differentiation along the ventriculus, except for the predominance of cells undergoing apocrine secretion in the anterior region. Apocrine secretion affects a larger extension and a greater number of cells in caeca than in ventriculus. Ventricular cells putatively secrete digestive enzymes, whereas caecal cells are supposed to secrete peritrophic gel (PG) glycoproteins. Feeding larvae with dyes showed that caeca are water-absorbing, whereas the posterior ventriculus is water-secreting. Midgut dissection revealed a PG and a peritrophic membrane (PM) covering the contents in anterior and posterior ventriculus, respectively. This was confirmed by in situ chitin detection with FITC-WGA conjugates. Ion-exchange chromatography of midgut homogenates, associated with enzymatic assays with natural and synthetic substrates and specific inhibitors, showed that trypsin and chymotrypsin are the major proteinases, cysteine proteinase is absent, and aspartic proteinase probably is negligible. Amylase and trypsin occur in contents and decrease along the ventriculus; the contrary is true for cell-membrane-bound aminopeptidase. Maltase is cell-membrane-bound and predominates in anterior and middle midgut. Digestive enzyme activities in hindgut are negligible. This, together with dye data, indicates that enzymes are recovered from inside PM by a posterior-anterior flux of fluid outside PM before being excreted. The combined results suggest that protein digestion starts in anterior midgut and ends in the surface of posterior midgut cells. All glycogen digestion takes place in anterior midgut.

Anatomic dilatation of the cardia and competence of the lower esophageal sphincter: a clinical and experimental study.

Anatomic and clinical data suggest that the gastroesophageal junction or cardia in patients with gastroesophageal reflux disease GERD) may be dilated. We hypothesized that anatomic dilatation of the cardia induces a lower esophageal sphincter dysfunction that may be corrected by narrowing the gastroesophageal junction (i.e., calibration of the cardia). We measured the perimeter of the cardia during surgery in control subjects and patients with GERD and Barrett's esophagus. We then tested our hypothesis in a mechanical model. The model was based on a pig gastroesophageal specimen with perpendicularly placed elastic bands around the cardia simulating the action of the "sling" and "clasp" fibers. "Dilatation" of the cardia was induced by displacing the sling band laterally and decreasing its tension. "Calibration" of the cardia was performed by reapproximation of the sling band toward the esophagus but maintaining the same tension as the dilated model. In the "basal," "dilated," and "calibrated" states, the perimeter of the cardia was noted and rapid mechanized pullback manometry with a water-perfused catheter was performed. The opening pressure was determined, and three-dimensional sphincter pressure images were analyzed. The average cardia perimeter was 6.3 cm in control subjects, 8.9 cm in GERD patients, and 13.8 cm in patients with Barrett's esophagus. The arrangement of the bands in the experimental model generated a manometric high-pressure zone similar to that in the human lower esophageal sphincter. Dilatation of the cardia resulted in a decrease in the resting pressure, length, and vector volume of the high -pressure zone, and reduced the opening pressure. Calibration restored the resting and opening pressure, and normalized the three-dimensional pressure image. In patients with GERD and Barrett's esophagus, the cardia is dilated. Our model supports the hypothesis that lower esophageal sphincter function is compromised by anatomic dilatation of the cardia and can be restored by approximation of the "sling" fibers toward the lesser curvature "clasp" fibers). This provides evidence for a correlation between gastroesophageal sphincter dysfunction in reflux disease and its correction by antireflux surgery.

[Characteristics of the venoms and digestive secretions of Aphonopelma seemanni and Sphaerobothria hoffmanni (Araneae: Theraphosidae) of Costa Rica]. / Algunas características de los venenos y secreciones digestivas de Aphonopelma seemanni y Sphaerobothria hoffmanni (Araneae: Theraphosidae) de Costa Rica.

A comparison of some components of the venoms of two Costa Rican tarantulas, Aphonopelma seemanni (Cambridge) and Sphaerobothria hoffmanni (Karsch) by polyacrylamide gel electrophoresis shows patterns similar to those of Dugesiella hentzi (Girard), a North American tarantula. The digestive secretions have proteins that do not enter the 15% gels; thus no bands are observed. The method used by the tarantulas to consume their prey involves the action of both the venom and the digestive secretions. The percent protein, pH, proteolytic activity and hemolytic activity of venom and digestive secretions of both species were determined, and a high proteolytic activity for digestive secretions was found.

Algunas características de los venenos y secreciones digestivas de Aphonopelma seemanni y Sphaerobothria hoffmanni (Araneae: Theraphosidae) de Costa Rica / Characteristics of the venoms and digestive secretions of Aphonopelma seemanni and Sphaerobothria hoffmanni (Araneae: Theraphosidae) of Costa Rica

A comparison of some components of the venoms of two Costa Rican tarantulas, Aphonopelma seeamanni (Cambridge) and Sphaerobothria hoffmanni (Karsch) by polyacrylamide gel electrophoresis shows patterns similar to those of Dugesiella hentzi (Girard), a North American tarantula. The digestive secretions have proteins that do not enter the 15% gels; thus no bands are obsorved. The method used by the tarantulas to consume their prey involves the action of both the venom and the digestive secretions. The percent protein, pH, proteolytic activity and hemolytic activity of venom and digestive secretions of both species were determined, and a high proteolytic activity for digestive secretions was found.

Effect of duodenal contents on the gastric antrum. Experimental study on dogs.

16 dogs were subjected to surgical techniques in order to maintain the gastric antrum in continuous and chronic contact with duodenal contents. Eight dogs were followed up for six months and the remainder for twelve months. There were no histological findings of atrophic gastritis or gastric ulcer.

Fisiología humana: respiración y digestión

Desarrolla la fisiología respiratoria y la fisiología digestiva en todos los aspectos

Fisiología humana: respiración y digestión

Desarrolla la fisiología respiratoria y la fisiología digestiva en todos los aspectos

Study of a human excluded jejunal loop (Thiry-Vella loop).

A case of a human jejunal loop excluded from the intestinal transit was studied. The loop was located in the retrosternal space as the first step of esophageal transit reconstruction, after an unsuccessful esophagocoloplasty performed in order to treat a caustic stenosis of the esophagus. The motility, secretion of electrolytes and the absorption of glucose and alanine by the loop were determined.

[Infusion of ileal juice by distal stoma]. / Infusao de suco ileal por estomia distal.

The authors present a simple and practical method to avoid the ileal juice expoliation in patients with ileostomy after intestinal resection. In the cases presented, after the resection, stomies were performed of the proximal and distal portions of the intestine, in relation to the extirpated segment. The juice collected in the proximal stomy was infused in the distal stomy, simulating that way the physiologic intestinal transit.