Definition of gastroduodenal junction in healthy subjects

Comparison of two techniques for a comprehensive gut histopathological analysis: Swiss Roll versus Intestine Strips

Assessing the gut mucosa milieu is important to grade the inflammatory process in conditions such as food hypersensitivity, allergy, gut parasitosis, etc. However, the gastrointestinal tract comprises a challenging system to evaluate, due to its thin tubular structure and mucosa, which suffer fast autolysis after death. Irrespective of the preferred inflammatory score system, it is important to choose the technique that will render the best tissue analysis. Thus, our aim was to compare two of the most frequently used methods to collect, process and analyze gut segments, the Swiss Roll and the Intestinal Strips. Normal C57Bl/6 mice were randomly assigned to Rolls or Strips group. After an overdose of anesthetics, segments of the duodenum, jejunum and ileum were collected and prepared accordingly for histological processing and analysis. Our results show the villi in the Rolls tend to be shorter and wider than those in the Strips in the duodenum and jejunum but not the ileum. No significant differences were observed in intra-epithelial lymphocytes and goblet cells counts. Finally, we staged each segment using our histomorphometric classification system, which revealed that although all animals presented a normal intestinal mucosa, those assigned to the Rolls group had their mucosa staged in the Infiltrative Stage while the Strips group had their mucosa staged as Normal. In conclusion, Swiss Rolls might be desirable for a wider assessment of the intestine, as it allows large segments to be analyzed at once, while Strips are better suited when detailed evaluation of each villus is intended.

Embryologic and anatomic basis of duodenal surgery

The following points should be remembered by surgeons (Table 1). In writing about the head of the pancreas, the common bile duct, and the duodenum in 1979, the authors stated that Embryologically, anatomically and surgically these three entities form an inseparable unit. Their relations and blood supply make it impossible for the surgeon to remove completely the head of the pancreas without removing the duodenum and the distal part of the common bile duct. Here embryology and anatomy conspire to produce some of the most difficult surgery of the abdominal cavity. The only alternative procedure, the so-called 95% pancreatectomy, leaves a rim of pancreas along the medial border of the duodenum to preserve the duodenal blood supply. The authors had several conversations with Child, one of the pioneers of this procedure, whose constant message was to always be careful with the blood supply of the duodenum (personal communication, 1970). Beger et al popularized duodenum-preserving resection of the pancreatic head, emphasizing preservation of endocrine pancreatic function. They reported that ampullectomy (removal of the papilla and ampulla of Vater) carries a mortality rate of less than 0.4% and a morbidity rate of less than 10.0%. Surgeons should not ligate the superior and inferior pancreaticoduodenal arteries because such ligation may cause necrosis of the head of the pancreas and of much of the duodenum. The accessory pancreatic duct of Santorini passes under the gastrointestinal artery. For safety, surgeons should ligate the artery away from the anterior medial duodenal wall, where the papilla is located, thereby avoiding injury to or ligation of the duct. "Water under the bridge" applies not only to the relationship of the uterine artery and ureter but also to the gastroduodenal artery and the accessory pancreatic duct. In 10% of cases, the duct of Santorini is the only duct draining the pancreas, so ligation of the gastroduodenal artery with accidental inclusion of the duct is catastrophic. With the Kocher maneuver, surgeons reconstruct the primitive mesoduodenum and achieve mobilization of the duodenum, which is useful for some surgical procedures. Surgeons should not skeletonize more than 2 cm of the first part of the duodenum. If more than 2 cm of skeletonization is done, a duodenostomy using a Foley catheter may be necessary to avoid blow-up of the stump secondary to poor blood supply. Proximal duodenojejunostomy is advised for the safe management of patients with difficult duodenal stumps. Roux-en-Y choledochojejunostomy and duodenojejunostomy divert bile and food in the treatment of the complicated duodenal diverticulum. The suspensory ligament may be transected with impunity. It should be ligated before being sectioned so that bleeding from small vessels contained within can be avoided. Failure to sever the suspensory muscle completely, which is possible if the insertion is multiple, fails to relieve the symptoms of vascular compression of the duodenum (Fig. 18). Mobilization, resection, and end-to-end anastomosis of the duodenal flexure have been performed as a uniform surgical procedure, avoiding the conventional gastrojejunostomy. With a large, penetrating posterior duodenal or pyloric ulcer, surgeons should remember that The proximal duodenum shortens because of the inflammatory process (duodenal shortening) The anatomic topography of the distal common bile duct and the opening of the duct of Santorini and the ampulla of Vater is distorted Leaving the ulcer in situ is wise Careful palpation for or visualization of the location of the ampulla of Vater or common bile duct exploration with a catheter insertion into the common bile duct and the duodenum are useful procedures In most cases, the common bile duct is located to the right of the gastroduodenal artery at the posterior wall of the first part of the duodenum. (ABSTRACT TRUNCATED)

The gastric transitional zones: neglected links between gastroduodenal pathology and helicobacter ecology

The gastric transitional zones are the junctional zones between the different types of mucosa: antral-body, body-cardia, and antrum-duodenum. In this article, the importance of the transitional zone in determining disease outcome, specifically duodenal ulcer, gastric ulcer, and possibly gastric cancer, is reviewed. Both gastric ulcers and duodenal ulcers are located immediately adjacent to the transitional zones. The transitional zones are dynamic rather than static areas. Local acid levels determine the behavior of Helicobacter pylori at the antral-body transitional zone and, as a consequence, the geographic distribution of gastritis in the stomach and the formation of duodenal ulcer and gastric ulcer. This review also explains that diffuse antral gastritis and multifocal atrophic gastritis are part of the same disease and not separate entities.

Helicobacter pylori infection and the pathogenesis of duodenal ulceration

Helicobacter pylori is a gram-negative spiral bacterium confined to the habitat of gastric-type epithelium. H. pylori causes duodenal ulceration by a cumulative effect of antral predominant gastritis with increased acid secretion, consequent gastric metaplasia in the duodenum (a site of further colonization by H. pylori), duodenitis, reduced duodenal bicarbonate secretion, and mucosal damage. Bacterial factors influence outcome. Major determinants are the production of a vacuolating toxin and the presence of CagA, an immunodominant product of a nonconserved gene cagA, a marker for the cag pathogenicity island that encodes virulence genes involved in induction of epithelial chemokine responses. In ulcer patients the mucosal immune response is polarized to a T-helper-1 (Th1) cell-mediated response, which may contribute to mucosal damage. Eradication of H. pylori restores acid output to normal. Loss of both acid and bacteria halts gastroduodenitis and allows ulcer healing. Gastric metaplasia does not regress in the short term.

Parietal cells in the duodenal bulb and their relation to Helicobacter pylori infection

AIM

To investigate the prevalence, and relation to Helicobacter pylori, of parietal cells in the duodenal bulb using a monoclonal antibody directed against H+,K(+)-ATPase (HK12.18).

METHODS

Twenty six patients with duodenal ulcer disease and 16 healthy controls were studied. H pylori status was determined by gastric histology and culture and by the 13C-urea breath test. Four biopsy specimens were taken from the duodenal bulb and stained with HK12.18. The presence/absence and number of parietal cells in the duodenal bulb were assessed blindly by a histopathologist.

RESULTS

The overall prevalence of parietal cells in the duodenal bulb was 31% (13/42) and was similar in patients with duodenal ulcer and in controls, and in H pylori positive and negative subjects. The median (range) number of parietal cells in the duodenal bulb was 7.5 (4-20) parietal cells/subject, and was similar in all four groups.

CONCLUSIONS

The prevalence of parietal cells in the duodenal bulb (31%) is notably higher than previously reported in endoscopic studies, and is in keeping with reports from studies on necropsy/operative specimens. There was no difference in the prevalence or number of parietal cells in the duodenal bulb between patients with duodenal ulcer and controls, regardless of H pylori status. These findings suggest that parietal cells in the duodenal bulb do not contribute to the pathogenesis of duodenal ulcer.

Five types of pyloric cells in the antral mucosa of the stomach

Only one type of pyloric cells in the exocrine antral glands is usually described in the literature. The review of 100 gastrectomy specimens revealed 5 types of pyloric cells: one composed of "ordinary" pyloric cells (i.e. cuboidal cells with ill-defined borders, pale, bubbly cytoplasm with an inconspicuous cytoplasmic network). The second type was characterized by pyloric cells with a small, regular vacuole, usually in a subnuclear position. The vacuole in such cells was negative for mucous stains. The third type of pyloric cells had a large intracytoplasmatic vacuole. Cells with this characteristic were found in cystically dilated pyloric glands. The vacuoles in such cells were usually negative for mucous stains although a rim of PAS or alcian blue positive substance was found in some vacuoles. The fourth type of pyloric cells had eosinophilic granules in the cytoplasm. These granules were proven to contain lysozyme. The fifth type had a non-vacuolated, homogeneous ("glassy") cytoplasm which was weakly positive for PAS but negative for acid mucins or mannosides. While the significance of the various types of pyloric cells herein described remains unclear, their easy identification in H & E stained preparations would permit more elaborated studies with histochemistry, immunohistochemistry and/or transmission electron microscopy in the future.

Loss of alkaline phosphatase activity in duodenal mucosa: a marker for precursors of gastric metaplasia?

Biopsy specimens from duodenal mucosa in 34 patients with upper gastrointestinal symptoms and endoscopically abnormal mucosa (including duodenitis, active duodenal ulcer, and healed duodenal ulcer) and in 9 patients with histologically normal mucosa were examined histologically for gastric metaplasia and endogenous alkaline phosphatase (AP) activity. Using haematoxylin and eosin (H&E) and periodic acid-Schiff (PAS), we found gastric metaplasia in 91.2 per cent (31 out of 34) of patients with altered duodenal mucosa and in 33.3 per cent (3 out of 9) of patients with histologically normal, non-inflamed duodenal mucosa (P less than 0.001). To characterize gastric metaplasia further, histochemical methods for AP activity were applied to duodenal mucosa specimens. No AP activity was detected in complete metaplastic cells, but focal or diffuse loss of AP activity was frequently shown in otherwise normal appearing enterocytes next to metaplastic cell groups. Focal loss of AP activity was also detected in seven out of nine healthy controls (= 77.8 per cent) which appeared normal when stained with H&E. Our results suggest that the loss of AP activity in enterocytes may be an early marker of developing gastric metaplasia or at least a morphological manifestation of cell damage.