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We report an unusual hepatoid adenocarcinoma in Barrett's esophagus with achalasia, which developed in a 44-year-old Japanese woman. The patient received an esophago-gastrectomy after diagnosis of the tumor and achalasia at the lower esophagus, 4 months before her death due to multiple metastatic tumors of the liver. The main granular tumor removed surgically was a hepatoid adenocarcinoma, mainly composed of clear cancer cells (alpha-1 antitrypsin, albumin and alpha-fetoprotein positive), with elements of choriocarcinoma and tubular adenocarcinoma. Non-neoplastic specialized columnar epithelium was present extensively near the oral side of the tumor edge in the esophagus, indicating Barrett's esophagus. This unusual tumor was therefore considered to have originated in Barrett's esophagus. The gastroesophageal reflux was presumed to have occurred for a long period, as there was a well-preserved fundic gland in the stomach and a history of frequent vomiting from the patient's youth, accounting for the appearance of achalasia.

Background: Sonic hedgehog (Shh) is an important endodermal morphogenetic signal during the development of the vertebrate gut. It controls gastrointestinal patterning in general, and gastric gland formation in particular. We have previously shown that Shh regulates gastric gland proliferation in the adult but detailed analysis of its expression along the adult gastrointestinal tract has never been undertaken. We therefore studied Shh expression along the normal human and rodent adult gastrointestinal tract as well as in intestinal metaplasia of the stomach, gastric and intestinal metaplasia of the oesophagus, and gastric heterotopia in Meckel’s diverticulum. Methods: The studies were performed with in situ hybridisation and by immunohistochemistry using an antibody that recognises the Shh precursor form. Results: We found that in the normal gastrointestinal tract, high levels of Shh were expressed in the fundic glands of the stomach. Shh expression was also found in fundic gland metaplasia and heterotopia. However, Shh expression was lost in intestinal metaplasia of the stomach. Conclusion: We found a strong correlation between Shh expression and fundic gland differentiation. Our current study therefore provides evidence that in addition to its role in gastric epithelial development, Shh plays a unique role in gastric epithelial differentiation in adults.

Upper endoscopy screening in an asymptomatic 56-year-old man showed a small, yellowish elevated lesion with a central depression on the posterior wall in the gastric cardia. Biopsy specimens from this lesion were suspicious of carcinoid tumor. We suspected this lesion to be a sporadic gastric carcinoid tumor with a diameter of 5 mm, limited to the mucosal layer. We then performed an endoscopic aspiration mucosectomy with a cap-fitted endoscope. Microscopically, the lesion obtained from the resected specimen was minimally invasive to the submucosa and showed highly differentiated columnar cells in irregularly anastomosing glands. Immunohistology was positive for pepsinogen-I, and MUC6, partially positive for H(+)/K(+)-ATPase, and negative for MUC5AC. In addition, it was positive for synaptophysin and CD56, and negative for chromogranin A. We finally diagnosed the patient as having gastric adenocarcinoma of fundic gland type (chief cell predominant type) with minimal invasion (100 µm) to the submucosa. Surveillance endoscopy with biopsy specimens and abdominal computed tomography at 1 year revealed no evidence of tumor recurrence. We herein report this rare case of gastric adenocarcinoma of fundic gland type (chief cell predominant type).

Recently, a new disease entity termed gastric adenocarcinoma of fundic gland type (GA-FG) was proposed. We treated five cases of GA-FG with endoscopic submucosal dissection. All tumors were small and located in the upper third of the stomach. Four tumors were macroscopically identified as 0-IIa and one was identified as 0-IIb. Narrow-band imaging with magnifying endoscopy showed an irregular microvascular pattern in 2 cases and a regular microvascular pattern in the remainder. All tumors arose from the deep layer of the lamina propria mucosae and showed submucosal invasion. Lymphatic invasion was seen only in one case, while no venous invasion was recognized. All tumors were positive for pepsinogen-I and MUC6 by immunohistochemistry. None showed p53 overexpression, and the labeling index of Ki-67 was low in all cases. All cases have been free from recurrence or metastasis. Herein, we discussed the clinicopathological features of GA-FG in comparison with past reports.

A 64-year-old Helicobacter pylori infection-naive woman was found to have a small (≤ 10 mm) depression on the anterior wall of the upper gastric body. On white light endoscopy, the lesion appeared to be inconspicuous, whitish with dilated vessels. 0.2% indigo carmine chromoendoscopy enable better visualization of the depression. On narrow band imaging with magnification, the microsurface structure of the surrounding mucosa was absent and a network of tortuous microvessels were observed within the depressed area. Endoscopic ultrasonography indicated that the tumor was confined to the mucosa. The lesion was removed by endoscopic submucosal dissection. Histological finding of the resected specimen revealed that carcinomatous tubules existed in the deep part of the lamina propria with minimal (300 μm) submucosal invasion which were covered with the atrophic non-neoplastic foveolar epithelium. The tumor was diffusely positive for MUC6 and pepsinogen-I, while it was negative for MUC5AC and H+/K+-ATPase. A diagnosis of early stage gastric adenocarcinoma of fundic gland type (chief cell predominant type) was made.

Portal hypertensive gastropathy is associated with fundic gland atrophy, resulting in a decrease in chief and parietal cells, and diminished acid secretion.Acid secretion by isolated parietal cells was measured (acridine orange retention), along with the levels of various second messengers (intracellular Ca(2+), cyclic adenosine monophosphate and protein kinase C) in the common bile duct, ligated portal hypertensive rats and compared with sham-operated controls.There was a significant decrease in the response of isolated parietal cells to the secretagogues histamine and carbachol. This resulted in the blunted acid secretion in the common bile duct ligated group. In addition, all the second messengers studied were significantly decreased as compared with the sham-operated controls.These results suggest that the blunted acid secretory response in the portal hypertensive rat is caused by an alteration in the intracellular signal transduction mechanism.

Fundic gland polyps (FGPs) are the most common gastric polyps. FGPs traditionally have been regarded as nondysplastic hamartomatous or hyperplastic lesions, but their pathogenesis remains unclear. We have recently shown that somatic adenomatous polyposis coli (APC) gene alterations are frequently present in FGPs associated with familial adenomatous polyposis (FAP), raising the possibility that mutations of the β-catenin gene affecting the APC/β-catenin pathway might be involved in the pathogenesis of sporadic FGPs. We analyzed somatic β-catenin gene mutations in 57 sporadic FGPs from 40 patients without FAP and in 19 FGPs from 13 FAP patients. Direct DNA sequencing of exon 3 encompassing the glycogen synthase kinase-3β phosphorylation region for β-catenin was used with confirmation by Hin fI restriction endonuclease digestion. The foveolar epithelium and dilated fundic glands of the polyps were separately microdissected and analyzed in 22 of 57 sporadic FGPs. Activating β-catenin gene mutations were present in 91% (52 of 57) of sporadic FGPs. Both the foveolar epithelium and the dilated fundic gland epithelium comprising the polyps were shown to have the same somatic β-catenin mutation in 21 of 22 (95%) sporadic FGPs. In contrast, β-catenin gene mutations were not present in any of the 19 FAP-associated FGPs ( P

The proton pump H+-K+-ATPase is the final common pathway mediating the production and secretion of hydrochloric acid by gastric parietal cells. The present studies were undertaken to examine whether the expression of gastric H+-K+-ATPase mRNA and protein changes are associated with the development of H+-K+-ATPase activity in the rat fundic gland. H+-K+-ATPase activity was examined in rat fundic gland at different stages from gestational day 18.5 to postnatal 8 weeks. The expression of H+-K+-ATPase mRNA was detected by in situ hybridization using a digoxigenin-labelled RNA probe with a tyramide signal amplification system. The expression of H+-K+-ATPase protein was evaluated by immunoblotting and immunohistochemistry using antibodies against H+-K+-ATPase alpha- and beta-subunits. We found that H+-K+-ATPase enzyme activity was detectable from the onset of gland formation (day 19.5 of gestation) and increased with age in the developing rat fundic gland. Expression of mRNA and protein was also discernible at the same time, and a progressive increase in expressions was observed as rats developed. Our results suggested that in developing rat fundic gland, the expression of both mRNA and protein of H+-K+-ATPase increased with age in a manner that parallels the development of H+-K+-ATPase enzyme activity.

In the chapter, an analysis of the literature on the relationship between Helicobacter pylori, the use of proton pump inhibitors and the development of atrophic gastritis is presented, and the difficulties of classifying gastritis and the new possibilities of quantifying chronic inflammation by morphometric analysis are discussed. The issue surrounding the necessity of eradicating H. pylori in H. pylori-positive patients has still not been solved. Most studies have now accepted that proton pump inhibitors indeed accelerate the onset of atrophic gastritis in H. pylori-positive patients, but evidence against such an association was published in one recent (Scandinavian) study; conclusions from this study have, however, been challenged by several groups. Some data are available on the efficacy of H. pylori eradication with regard to the prevention of atrophy. The limited significance of the development of parietal cell protrusions and fundic gland cysts is better understood, but much less is known of the development and long-term consequence of H. pylori-induced autoimmune gastritis. Finally, recent studies in H. pylori-positive patients indicate that treatment with proton pump inhibitors may promote bacterial N-nitrosation formation. These data taken together suggest that the eradication of H. pylori may be based not only on morphological arguments, but also on bacterial alterations in the gastric milieu.

Fundic gland polyps (FGPs) are the most common gastric polyps in patients with familial adenomatous polyposis (FAP). FGPs have traditionally been regarded as nonneoplastic, possibly hamartomatous lesions, but the pathogenesis of FGPs in both FAP and sporadic patients remains unclear. FGPs in FAP can show foveolar dysplasia, and rarely invasive gastric adenocarcinoma has been reported in patients with FAP and fundic gland polyposis. Using direct gene sequencing and allelic loss assays at 5q, we analyzed somatic adenomatous polyposis coli (APC) gene alterations in 41 FAP-associated FGPs (20 with foveolar dysplasia, six indefinite for dysplasia, and 15 nondysplastic) and 13 sporadic FGPs. The foveolar epithelium and dilated fundic glands of the polyps were separately microdissected and analyzed in 25 of 41 FAP-associated FGPs and 13 of 13 sporadic FGPs. Somatic APC gene alterations were identified frequently (21 of 41 cases, 51%) in FAP-associated FGPs. Both the foveolar epithelium and the dilated fundic gland epithelium comprising the FGPs were shown to carry the same somatic APC gene alteration in 24 (96%) of 25 cases. Furthermore, there was no difference in the frequency of somatic APC gene alterations between FGPs with foveolar dysplasia (10 of 20, 50%), indefinite for dysplasia (four of six, 67%), and nondysplastic (seven of 15, 47%) in FAP patients (P = 0.697). In contrast, FGPs from non-FAP patients showed infrequent (one of 13, 8%) APC gene alterations (P = 0.008). These results show that FGPs in FAP patients are pathogenetically distinct from sporadic FGPs. Somatic, second-hit APC gene alterations, which precede morphological dysplasia in many FAP-associated FGPs, indicate that FGPs arising in the setting of FAP are neoplastic lesions.

The development of rat fundic gland was studied by immunohistochemistry using a recently developed monoclonal antibody, HIK 1083, at both light and electron microscope levels. Antibody HIK 1083 recognized oligosaccharides with a non-reducing terminal alpha-linked N-acetylglucosamine (GlcNAc) residue. In the developing rat fundic gland, cells expressing alpha-GlcNAc residues were discernible from day 19.5 of gestation and continued to exist till adult. The distribution of the alpha-GlcNAc expressing cells was consistent with that described previously for cells reacting to Griffonia simplicifolia lectin (GSA-II) in all developmental stages. These cells were located at the bottom of the fundic gland when they first appeared. With the elongation and maturation of the gland, these cells moved upwards and were finally restricted in the neck region of the gland. Combining previous reports and the present electron microscopical observations, HIK 1083-positive cells in the adult rat fundic gland are mucous neck cells. The interaction between antibody HIK 1083 and GSA-II lectin was investigated. GSA-II prevented the subsequent binding of HIK 1083, while HIK 1083 did not prevent GSA-II binding to mucous neck cells. Our results suggested that alpha-GlcNAc residues exist in rat fundic gland from day 19.5 of gestation and continue to exist till adult. Cells expressing alpha-GlcNAc residues appeared as typical mucous neck cells from postnatal four weeks.

BACKGROUND/AIMSThe characteristics of pepsinogen screening for gastric cancer were investigated to establish a suitable cut off point for identifying gastric cancer, using endoscopic diagnosis as the yardstick.SUBJECTS/METHODSSerum pepsinogen concentrations were measured in 5113 subjects who were also screened for gastric cancer by endoscopy. The cut off point for pepsinogen was determined using receiver operator characteristics curves.RESULTSThe most suitable cut off point was a pepsinogen I concentration of less than 70 ng/ml and a ratio of pepsinogen I to pepsinogen II of less than 3.0. Using this cut off point, the sensitivity and specificity of pepsinogen screening for gastric cancer were 84.6% and 73.5% respectively. All cases of gastric cancer in patients with severe atrophic gastritis were detected. However, two of four cases of gastric cancer in patients with mild atrophic gastritis were overlooked. In subjects with mild atrophic gastritis, when gastric cancer arises within the fundic gland region, the size of the lesion determines whether it is possible to detect cancer by serum pepsinogen screening.CONCLUSIONPepsinogen screening has many advantages, including its suitability for combination with other screening methods because it is simple and inexpensive.

Background/Aims: Matrix metalloproteinases (MMPs) are endopeptidases that degrade extracellular matrix and are involved in the pathogenesis of gastrointestinal ulcer and cancer along with tissue inhibitors of metalloproteinases (TIMPs). The purpose of this study is to examine their localization and functions in the normal stomach. Methods: We examined the localization of MMP-1, MMP-2, MMP-9 and TIMP-2 in normal human and rabbit stomachs by light- and electron-microscopic immunohistochemistry and Western blotting, and the enzymatic activities of MMP-2 and MMP-9 by gelatin zymography. Results: Immunohistochemistry revealed their localization in parietal cells, and surface and foveolar epithelial cells. Electron-microscopic immunohistochemistry of parietal cells showed immunolabeling of MMP-2 and TIMP-2 in the cisternae of the rough endoplasmic reticulum, and that of MMP-1 and MMP-9 in tubular structures in their cytoplasm. Western blotting revealed that the densities of MMP-2 and MMP-9 bands were higher for the fundic gland region than for the pyloric gland region. Gelatin zymography revealed that tissue extracts of the fundic gland region exhibited higher enzymatic activity of MMP-2 and MMP-9 than those of the pyloric gland region. Conclusion: Normal rabbit and human stomachs contain MMP-1, MMP-2, MMP-9, and TIMP-2 and these are mainly localized in, and synthesized by parietal cells.

Since 1992 there have been reports of proton pump inhibitors being associated with fundic gland-type gastric polyps. Endoscopic and histologic characteristics and natural history of these polyps have not been clearly defined. We performed a retrospective study of patients on long-term treatment with proton pump inhibitors who developed gastric polyps. Gastric polyps developed in 17 (10 males and 7 females, 7.3%) of the 231 patients who underwent 2 or more upper endoscopies for complicated gastroesophageal reflux disease and who were receiving long-term treatment with proton pump inhibitors. The mean interval of proton pump inhibitor use after which an endoscopy revealed gastric polyps was 32.5 months. In 1 patient, discontinuation of treatment resulted in disappearance of the polyps within 3 months. The polyps recurred 4 months after the treatment was restarted. Endoscopy established that typical polyps were generally small (

The expression of cytochrome P450 3A4 (CYP3A4) in the foveolar epithelium of the human stomach with intestinal metaplasia was studied using immunohistochemistry, western blotting and reverse transcription polymerase chain reaction (RT‐PCR). CYP3A4 was immunohistochemically detected in the foveolar epithelium with intestinal metaplasia, but was not detected in foveolar epithelium without intestinal metaplasia, in the pyloric gland or in the fundic gland of the stomach. Western blotting and RT‐PCR demonstrated that CYP3A4 protein and mRNA were expressed in the liver and pyloric gland mucosa with intestinal metaplasia, but not in the fundic gland mucosa without intestinal metaplasia. Possible roles of CYP expression in the gastric mucosa with intestinal metaplasia in human stomach carcinogenesis are briefly discussed.

A monoclonal antibody against histamine has been produced. A histamine-haemocyanin conjugate prepared using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a coupling agent was used for immunizing mice. Immunized mice were sacrificed to prepare monoclonal antibody using a hybridoma technique. On immunospot assay, the hybridoma culture supernatant containing a monoclonal antibody was capable of detecting 50 pmol of histamine. Using this antibody, we examined the cellular localization of histamine-like immunoreactivity in the stomach of normal or alpha-fluoromethylhistidine-treated rats and mice. Immunoreactive cells were abundant in the gastric mucosal layer. These positive cells were often located in the basal half of the fundic gland but were rare in the pyloric gland. The cells, small or medium in size, spindle or cone in shape, were intermingled with immunonegative epithelial cells. In the cytoplasm of the positive cells, granular reaction products were densely deposited. In addition, a few positive cells, identified as mast cells by Toluidine Blue staining, were distributed mainly in the submucosal and muscular layer. The antibody preabsorbed with 10 mM histamine gave no positive immunostaining. For pharmacological study, some rats were injected six times with c-fluoromethylhistidine every 8 h. In these rats, positive cells except mast cells were no longer detected. In conclusion, the monoclonal antibody produced appears to be highly specific for histamine. Its application in immunohistochemistry should provide a powerful tool for analysing the roles of histamine in enterochromaffin-like or mast cells in the stomach.

Oral administration of an ammonia solution (0.01%) or a sodium taurocholate solution (TCA solution, 5 mM) as drinking water for 4 weeks or 13 weeks, respectively, resulted in gastric mucosal thinning and decreased parietal cell numbers. Oral administration of TCA solution also caused cell infiltration in the lamina propria of the mucosa and mucosal fibrosis. When lafutidine (3, 10 mg/kg) was administered orally once daily for one week after the withdrawal of ammonia or TCA solution, the recovery of the mucosal thickness in the fundic gland area and the parietal cell number were significantly accelerated, and the recovery of mucosal thickness in the pyloric gland area also tended to be accelerated. Lafutidine at 10 mg/kg for 1 week had no influence on normal mucosal thickness and parietal cell numbers. At the doses that produce equal or greater acid antisecretory effect than lafutidine, oral administration of cimetidine (30 mg/kg) and famotidine (1 mg/kg) had no effect on either of these atrophy indexes. These results demonstrate that lafutidine, unlike cimetidine and famotidine, can accelerate the healing of mucosal injuries in ammonia- and TCA-induced chronic gastritis models.

Results of pathological studies of surgical specimens have led to widespread acceptance of the belief that with aging the gastric mucosa gradually becomes atrophic and the incidence of intestinal metaplasia increases. To distinguish natural age-related changes in the incidence of fundic gland atrophy and intestinal metaplasia from changes related to disease, we studied stomachs removed at autopsy from 187 people who had had no gastric diseases and were over 60 years old at the time of death (27 were over 100 years old). The autopsies were performed at Tokyo metropolitan geriatric hospital. None of the stomachs had circumscribed gastric lesions, and those found to have cancer or ulcer were excluded. Age at the time of death was not associated with the incidence of fundic gland atrophy or of intestinal metaplasia. Thus, the incidences of fundic gland atrophy and of intestinal metaplasia in elderly people were much lower than those found in studies of surgical specimens. In addition, the incidences of fundic gland atrophy and of intestinal metaplasia did not differ significantly between the sexes, regardless of age.

We experienced a case of multiple carcinoid of the stomach with hypergastrinemia and type A gastritis in a 35-year-old man. Upper gastrointestinal series revealed an about 1cm polyp of Yamada's type II or III in the posterior wall of the upper body of the stomahc adjacent to the greater curvature and multiple minute polyps ranging from the upper body to fornix. All polyps were diagnosed as carcinoid on endoscopic biopsy. Ultrasonic endoscopy revealed that the lesions were localized in the submucosal layer. Serum gastrin level was as high as 1, 950pg/ml.Total gastrectomy was carried out and multiple gastric carcinoids (sm, n0) with type A gastritis were histologically confirmed. After the operation, serum gastrin level was normalized and the patient has been doing well as of 3 years or more after the operation. In the treatment of multiple gastric carcinoid with type A gastritis, total gastrectomy with lymph node dissection would have to be the standard operative procedure, in order to resect the fundic gland area completely which can be the origin of carcinoids and endocrine cell micronest.

Gastric neoplasia of chief cell-predominant type (GN-CCP) has been reported as a new, rare variant of gastric tumor. GN-CCPs were defined as tumors consisting of irregular anastomosing glands of columnar cells mimicking chief cells of fundic gland with nuclear atypia and prolapse-type submucosal involvement. We comparatively evaluated clinicopathologic features between 31 GN-CCPs and 130 cases of conventional gastric adenocarcinoma invading into submucosa (CGA-SM) in addition to nuclear β-catenin immunolabeling and direct sequencing of members of the Wnt/β-catenin pathway, CTNNB1, APC, and AXIN, in a subset of these tumors. GN-CCP presented as small protruded lesions located in the upper third of the stomach, with minimal involvement into the submucosa and rare lymphovascular invasion. None of the lesions have demonstrated a recurrence of disease or metastasis on follow-up. Nuclear β-catenin immunolabeling was higher in GN-CCP (labeling index [LI]: median, 19.3%; high expresser [LI >30%], 7/27 cases [26%]) than CGA-SM (median LI, 14.7%; high expresser, 1/19 cases [6%]). Missense mutation of APC was observed in 1 GN-CCP but not CGA-SM. Missense or nonsense mutations of CTNNB1 and AXIN1 were higher in GN-CCPs (14.8%, both) than CGA-SMs (5.3%, both). Missense mutations of AXIN2 were higher in GN-CCPs (25.9%) than in CGA-SMs (10.5%). Overall, 14 (51.9%) of 27 GN-CCPs and 5 (26.3%) of 19 CGA-SM cases harbored at least 1 of these gene mutations. In conclusion, GN-CCPs as a unique variant of nonaggressive tumor are characterized by nuclear β-catenin accumulation and mutation of CTNNB1 or AXIN gene, suggesting activation of the Wnt/β-catenin pathway.

We read with great interest the article by Worthley et al 1 that recently appeared in your Journal, and the subsequent letter on the same subject.2 We would like to make some comments on this interesting topic. Worthley et al reported a new autosomal dominant syndrome that they named gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). GAPPS appears to be characterised by proximal gastric polyposis, particularly of the fundic gland type that often displays low and high grade dysplasia with early development of gastric cancer. These patients showed no evidence of colonic polyps, and other genetic syndromes were excluded. Yanaru-Fujisawa et al reported a further family with GAPPS. So far, dysplasia has been described …

In order to understand the histogenesis of precancerous and cancerous lesions, we investigated the clonality of normal single fundic gland and single pyloric gland using X-chromosome inactivation. Sixty percent of single fundic glands were cell populations methylated at the same alleles of the X-chromosome (homotypic) and 40% consisted of mixed cells methylated at different alleles of the X-chromosome (heterotypic). Among 28 fundic glands in which the clonality of the upper parts and that of the lower parts were analyzed separately, 11 glands were heterotypic in either part and 4 glands were homotypic with different allelic methylation in the upper part and in the lower part. Ninety-six percent of the single pyloric glands were homotypic and 4% were heterotypic. The results show the differences in the development of the fundic glands and the pyloric glands.

The ontogeny of sulphated glycoconjugate-producing cells in the rat fundic gland has been studied using high iron diamine (HID), Alcian Blue (AB) at pH 1.0, high iron diamine in combination with Alcian Blue at pH 2.5 (HID-AB), cationic colloidal gold (CCG) at pH 1.0 under light microscopy and CCG (1.0), HID-thiocarbohydrazide (TCH)-silver proteinate (SP)-physical development (PD) under electron microscopy. From day 19.5 of gestation, sulphated glycoconjugate-producing cells were discernible under both light and electron microscopy. The development of such cells can be classified into four stages: (1) a prenatal period from day 19.5 of gestation extending to 0.5 days after birth; (2) 1 day to 2 weeks after birth; (3) 2 to 4 weeks after birth; and (4) the final period from 4 to 8 weeks after birth. Glycoconjugate-producing cells reached maturity by 4 weeks after birth. Our results indicated that glycoconjugate-producing cells were cells along the wall of foveolar lumen, but not those covering the gastric mucosa surface. Our results also suggested that the trans to transmost Golgi apparatus lamellae were the sites of sulphation in the developing rat stomach.

Gastric adenocarcinoma of fundic gland type (GA-FG) with chief cell differentiation was recently proposed as an extremely rare type of gastric adenocarcinoma. Here, we report 4 cases of GA-FG with chief cell differentiation. Endoscopic features included a submucosal tumor shape or a flat shape, whitish discoloration and dilated vessels on the surface. The tumors were located in the upper or middle third of the stomach. All cases were preoperatively diagnosed as GA-FG by biopsy, and endoscopic submucosal dissection was performed. Resected specimens revealed well-differentiated adenocarcinomas resembling chief cells. Tumor cells were diffusely positive for pepsinogen-I, but partially positive for H(+)/K(+)-ATPase in scattered locations around the tumor margin. Despite the presence of minimal invasion of the carcinoma into the submucosal layer, which was observed in two cases, neither lymphatic nor venous invasion was detected in any of the cases. Finally, all cases showed less aggressive clinical behavior with low grade malignancy.

AIM: To analyze the lipid distribution in gastric mucosae. METHODS: Imaging mass spectrometry (MS) is a useful tool to survey the distribution of biomolecules in surgical specimens. Here we used the imaging MS apparatus named iMScope to identify the dominant molecules present in the human gastric mucosa near the fundic glands. Five gastric specimens were subjected to iMScope analysis. These specimens were also analyzed by immunohistochemistry using MUC5AC, H(+)-K(+)-ATPaseβ Claudin18 antibodies. RESULTS: Three major molecules with m/z 725.5, 780.5, and 782.5 detected in the gastric mucosa were identified as sphingomyelin (SM) (d18:1/16:0), phosphatidylcholine (PC) (16:0/18:2), and PC (16:0/18:1), respectively, through MS/MS analyses. Using immunohistological staining, SM (d18:1/16:0) signals were mainly co-localized with the foveolar epithelium marker MUC5AC. In contrast, PC (16:0/18:2) signals were observed in the region testing positive for the fundic gland marker H(+)-K(+)-ATPaseβ. PC (16:0/18:1) signals were uniformly distributed throughout the mucosa. CONCLUSION: Our basic data will contribute to the studies of lipid species in physical and pathological conditions of the human stomach.

Background The highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) emerging in China exhibits high fatality to pigs. However, the mechanism related to the increased pathogenicity of the virus remains unclear. In the present study, the differences in tissue tropism between the highly pathogenic PRRSV strain (JXwn06) and the low pathogenic PRRSV strain (HB-1/3.9) were investigated using PRRSV-specific immunohistochemistry (IHC) staining to provide evidence for elucidating possible mechanism of the pathogenicity of Chinese highly pathogenic PRRSV. Findings IHC examination showed that PRRSV antigen in the tissues including spleen, tonsil, thymus, kidney, cerebellum, stomach, small intestine, large intestine, turbinal bone and laryngeal cartilage was positive in more pigs inoculated with JXwn06 than HB-1/3.9, and the tissues including trachea, esophagus, liver, mandibular gland and thyroid gland were positive for viral antigen in the pigs inoculated with JXwn06, but not in the pigs inoculated with HB-1/3.9. Meanwhile, we observed that epithelium in tissues including interlobular bile duct in liver, distal renal tubule of kidney, esophageal gland and tracheal gland were positive for viral antigen only in JXwn06-inoculated pigs, and epithelium of gastric mucosa and fundic gland, and intestinal gland were positive for viral antigen in both JXwn06- and HB-1/3.9-inoculated pigs, using monoclonal antibodies to N and Nsp2 proteins. Conclusions Taken together, these findings indicate that the highly pathogenic PRRSV JXwn06 displays an expanded tissue tropism in vivo, suggesting this may contribute to its high pathogenicity to pigs.

This experiment was conducted to examine the effect of dietary copper supplementation on ghrelin mRNA expression level in the fundic gland of growing pigs. A total of 45 crossbred pigs were randomly assigned to three groups of 15 pigs, five replicates of three animals comprised each group. Pigs were allocated to diets that contained 5 mg/kg copper (as the control group), 125 mg/kg copper sulfate, or 125 mg/kg copper methionine. At the end of the experiment, five pigs were selected at random from each group, slaughtered, and collected the fundic gland for determination of ghrelin mRNA expression level. The results showed that average daily gain, average daily feed intake, absolute weight, serum growth hormone (GH) concentration, and ghrelin mRNA level were higher in pigs fed the diets with 125 mg/kg copper methionine and 125 mg/kg copper sulfate (P

Transmembrane protein 166 (TMEM166) is a novel human regulator involved in both autophagy and apoptosis. In this study, we generated a specific rabbit polyclonal antibody against human TMEM166 and assessed the expression of this protein in various human normal and tumor tissue samples by tissue microarray-based immunohistochemical analysis. Varying TMEM166 protein levels were expressed in a cell-type and tissue-type-specific manner in detected tissues or organs. Strong TMEM166 expression was shown in the glomerular zona of the adrenal cortex, chromophil cells of the pituitary gland, islet cells, squamous epithelium of the esophagus mucosa, the fundic gland, and hepatocytes. Moderate or weak TMEM166 staining was identified in the parathyroid gland, the testis, vaginal stratified squamous cells, lung macrophages, hematopoietic cells, renal tubular epithelial cells, macrophages in the spleen red pulp, and neuronal cells in the cerebral cortex. Some tissues failed to stain for TMEM166, such as adipose tissue, colon, cerebellum, lymph node, mammary gland, ovary, prostate, rectum, skin, small intestine, thyroid gland, tonsil, and thymus. In comparing human normal and tumor tissues, TMEM166 expression was widely downregulated in the cancer tissues. Our studies provide the basis for future investigations into cell-type-specific functions of this protein in human normal and tumor tissues.

The stomach is a complex organ, carrying out diverse functions, such as the reception and grinding of ingested food; the secretion of acid, digestive enzymes, intrinsic factors, and mucus; and the transfer of the processed food into the intestine. These functions are integrated by a complex array of neural and peripheral control mechanisms that regulate gastric activity in concert with that of the entire digestive system, as well as other organs. To perform such complex activities, the mucosal lining of the stomach varies, and the mucosa is generally classified as cardiac, fundic, or antral, according to the anatomical location. The mucosal glands of these regions contain specialized cells that play key regulatory functions. For instance, gastrin, secreted from G cells in the antrum, regulates acid secretion and controls proliferation of the gastric mucosa, and the recently identified ghrelin, which is secreted from X-like cells in the fundic gland, seems to be involved in controlling appetite, as well as in gut motility. However, under normal conditions, the endoscopic differentiation of these specialized mucosal areas is difficult, even by an experienced hand. A number of exogenous and endogenous factors, such as infection (most notably with Helicobacter pylori); chemical injury, such as that caused by nonsteroidal anti-inflammatory drugs or bile acid; autoimmunity; and circulatory changes are known to affect the macroscopic appearance of the gastric mucosa. The clinical diagnosis of gastritis is based on endoscopically detectable mucosal changes, although the diagnostic sensitivity and accuracy depends on the observer. Therefore, the sensitivity and reproducibility are generally considered to be rather poor for differentiating subtle alterations such as these seen in gastritis [1]. In order to overcome this problem, an attempt to semiquantitatively score the mucosal appearance, to facilitate objective assessment, has been proposed, in line

The majority of ghrelin producing cells (GPC) are present in the fundic gland of the stomach and recognized as X/A like cells. The detailed distribution of GPC in the stomach is still unknown in healthy and pathological subjects.We investigated the detailed distribution of GPC in the stomach, especially in relation with chronic gastritis, using surgical specimens from 12 patients with early gastric cancer. Either the anterior or posterior half of the whole stomach, which was a counterpart of the tumor bearing side, was subjected for immunohistochemistry of ghrelin, and the number of total GPC were semi quantitatively evaluated as GPC score. GPC score was compared with the degree of chronic gastritis, serum ghrelin concentration and body weight.GPC was not observed in the pyloric gland, but heterogeneously distributed in the fundic gland mainly in upper body and the greater curvature. The GPC score showed about nine-fold difference, which correlated well with the degree of chronic gastritis by Sydney score (r = -0.84, P 0.001). The serum ghrelin concentration was basically determined by the GPC score (r = 0.75, P = 0.0047); however, the obese patients showed low serum ghrelin concentration in spite of the presence of abundant GPCs. In the low GPC score patients, serum ghrelin was constantly low regardless of their body weight.GPC was inversely correlated with progression of chronic gastritis. Its quantification using immunohistochemistry of the whole stomach was useful to comprehensively evaluate ghrelin profile.

Recently, fundic gland type gastric adenocarcinoma (GA-FG) has been reported as a new entity. This report describes GA-FG among Koreans for the first time. From March 2008 to July 2010 we identified only three cases of GA-FG out of over 6,000 GAs resected by endoscopy or surgery. Cell differentiation by mucin proteins, pepsinogen-I, and H+/K+-ATPase was evaluated. All three cases were male patients and diagnosed as early stage GA. Histologically, GA-FGs were well-differentiated adenocarcinoma with pale gray-blue, basophilic columnar or cuboidal cells and mildly enlarged nuclei, resembling chief cells. All three cases were positive for pepsinogen-I and were classified as gastric mucin phenotype. Among three histologic subtypes of GA-FG, since tumors were mainly composed of chief cells, our three cases were classified as chief cell predominant type. In conclusion, GA-FG is very rare among Koreans and pepsinogen-I and MUC6 expression are typical immunohistochemical findings in GA-FG suggesting differentiation toward fundic glands.

In dogs Helicobacter spp. are found in all gastric regions usually localized in the surface mucus, gastric glands and parietal cells. The aim of this study was to detail the distribution of Helicobacter spp. in the fundic mucosa of asymptomatic Beagle dogs and their intracellular localization within parietal cells, in order to evaluate species-specific pathogenetic effects on gastric cells. The presence of Helicobacter spp. was investigated by immunohistochemistry, TEM, and PCR in the fundic mucosa of six Beagle dogs. Helicobacter spp. were found in all dogs examined, and H. bizzozeronii and H. felis were identified by PCR and confirmed by TEM. In the lumen of the fundic glands, co-localization was common. H. bizzozeronii was present in larger numbers than H. felis in both intraluminal and intraparietal localization. The amounts of H. bizzozeronii were similar in superficial and basal portions of the glands. H. felis was predominantly localized in the superficial portions of gastric glands but almost absent from the base. Within parietal cells, most Helicobacter organisms were intracanalicular, but intact and degenerate Helicobacter organisms were also visualized free in the cytoplasm or in secondary lysosomes. No specific degenerative lesions were found in infected parietal cells. Helicobacter organisms were also observed within macrophages in the lamina propria. In conclusion, there is a differential distribution of H. bizzozeronii and H. felis in the fundic mucosa of Beagle dogs, and their intracellular localization in parietal cells and macrophages suggests novel pathogenic scenarios for the development of immune response and maintenance of chronic gastritis in dogs.

We examined the histological characteristics of the foveolar zone of the gastric body mucosa, using dye endoscopy and endoscopic biopsy. In 63 patients, the gastric area type of the gastric body was placed in one of the following categories; fundic gland type 0 (F0), where small and fine areas are arranged closely to one another; F1, where the areas are largest in size, round and high; F2, where the areas are intemediate in size but not so high; F3, where small and flat areas are loosely arranged; pseudo-pyloric gland type 1 (Pb1), where the areas are regular in size and arrangement; and the completely atrophic gland type (Pb2) with areas irregular in size and arrangement. The histological characteristics of the foveolar zone were emmined on printed microphotographs of the biopsy specimens of the gastric body. The density of the gastric pit was defined as the number of pits in a 1 mm width of the mucosal surface and depth of the foveolae was measured as the distance between the top and bottom (or the isthmus) of the foveolae as seen on vertical sections. The gastric pit density and depth of the foveolae were dense and shallow, respectively, in FO and sparse and deep, in Pbl and Pb2 respectively. The degree of these factors showed independency in area types F0, F1 and Pb2 and there were correlations of P

The influence of gastric pH on intestinal metaplasia was examined in male Crj:CD(SD) rats. At the age of 5 weeks, animals were irradiated with two 10 Gy doses of X-rays to the gastric region at a 3-day interval (total 20 Gy), and 6 months after irradiation, received either secretin or histamine in silicon tubes for 2 months or had their bilateral submandibular salivary glands removed. The incidence of intestinal metaplasia in the fundus of animals after administration of secretin or histamine, or removal of the salivary glands were reduced, along with the pH values, as compared with values for rats given X-rays alone. In both the pyloric and the fundic gland mucosae, the numbers of alkaline phosphatase (ALP)-positive foci and type B metaplasias (intestinal crypts without Paneth cells) were also significantly decreased (P < 0.01). In a second experiment, started six months after irradiation, rats were kept on 1% sodium chloride (NaCl) diet for 6 months. Subsequent removal of salivary glands along with histamine treatment brought about a marked drop in pH and in numbers of ALP-positive foci after three and five days. The present results thus indicated that development and maintenance of intestinal metaplasia can be influenced by a decrease of pH value.

In a recent 7-year period, 349 patients were operated on gastric cancer at the department, and 55 of them had a pathologically “scirrhous type” infiltration in stromal reaction. In this study the growth pattern, development, and prognosis of gastric cancers of this type were examined. In the fundic gland area, cancer cells that have a productivity of fibrosis may develop into the “linitis plastica type” carcinoma without ulceration before the submucosal infiltration. If the submucosal infiltration is preceded by ulceration, such cells may develop into Borrmann type 3 or 4 in approximately the same frequency through IIc advanced type. In the pyloric gland area, the carcinomas grow to be Borrmann type 3 or 4 through IIc advanced type under the influence of ulceration, where Borrmann type 3 carcinomas are more common. Commonly the scirrhous carcinomas of the stomach are far advanced, and the prognosis is very poor because of widespread peritoneal dissemination and lymph node involvement. However, if these cases are resected in the depth of “sm or pm”, there is no recurrence and death case in our experience, and the prognosis is expected as well.

Shh (Sonic Hedgehog) is a morphogen involved in gastric fundic gland differentiation in the adult. Shh expression is reduced in Helicobacter pylori-associated intestinal metaplastic change of the gastric epithelium and mice that lack Shh show intestinal transformation of the gastric mucosa. Similarly, in the stomach of Cdx2 (caudal-type homeobox 2)-transgenic mice, the gastric mucosa is replaced by intestinal metaplastic mucosa. The aim of the present study was to use Cdx2-transgenic mice to investigate: (i) Shh expression in the intestinal metaplastic mucosa of the Cdx2-transgenic mouse stomach; and (ii) the relationship between Shh and Cdx2. We determined that Shh mRNA levels were dramatically reduced in the intestinal metaplastic mucosa of the Cdx2-transgenic mouse stomach compared with the normal (wild-type) mouse stomach. This was not due to hypermethylation of the Shh promoter, but instead we showed that Cdx2 directly bound to the TATA box region of the Shh promoter. Cdx2 also down-regulated transcription of the Shh gene in the human gastric carcinoma cell lines AGS, MKN45 and MKN74. In conclusion, Cdx2 reduced Shh expression by binding to the unmethylated Shh promoter in the intestinal metaplastic mucosa of Cdx2-transgenic mouse stomach.

We investigated the endoscopic and histopathological characteristics of 112 gastric polyps on the gastric body. According to the histopathological findings of the glands in the biopsy specimens, we classified the polyps into 6 categories; dense fundic gland type (group A), sparse fundic gland type (B), mixed fundic and pyloric gland type (C), pyloric gland type (D), complete atrophic gland type (E) and others (F). The grade of atrophic gastritis was defined by the fundic-pyloric border type of the stomach, and was found to change from mild to severe respectively in groups A to E. The gastric area type of background fundic gland mucosa also changed from F0 to F3 in parallel with the order of the groups A to E. Thirty-five of the 36 polyps in group A, all 19 in group B, 2 out of 3 in group C, 1 of 4 in group D, and the 1 in group E were located on the dye-endoscopically defined fundic gland mucosal area. The gland type of biopsy specimens which were obtained from the mucosa adjacent to the polyps changed from fundic to fundic-pyloric and to pyloric type in groups A to E respectively. In conclusion, the histopathological findings of polyps on the gastric body reflect the background mucosa, and in particular the extent of the atrophic change of the stomach. The majority of polyps, either fundic gland polyps (groups A and B) or hyperplastic polyps (groups C, D and E), on the gastric body were found to be the same gland type as their respective background mucosa. They thus seem to fall into the same category as hyperplastic polyps of background mucosal origin but are not the same as a hamartomatous polyp.

Two hydrophilic, low temperature-embedding resins, Lowicryl K4M and LR White, were compared in lectin cytochemistry. Post-embedding staining of colloidal gold-labeled Griffonia symplicifolia agglutinin II (GSA-II) resulted in staining of the Golgi apparatus and mucous granules of mucous neck cells in the gastric fundic gland, pylorocytes, and Brunner's gland cells embedded in either resin, although it was much easier to make ultra-thin sections with LR White-embedded material than with the other. Post-fixation with uranyl acetate followed by LR White embedding improved general ultrastructure so that lectin binding sites were identified precisely. All examined lectins, soybean agglutinin (SBA), Maclura pomifera agglutinin (MPA), GSA-II, and Ulex europaeus agglutinin I (UEA-I), stained mucous granules and the Golgi apparatus, in which the staining pattern was characteristic of each lectin: cis cisternae were labeled with SBA and MPA, intermediate cisternae with GSA-II, and trans cisternae and mucous granules with SBA, GSA-II, UEA-I, and lightly with MPA. No labeling was observed in the rough endoplasmic reticulum with any lectin. These findings suggest that the Golgi apparatus is the site of O-linked glycosylation and can be divided into at least three distinct compartments with regard to the glycosylation.

Congenital polyps of the posterior urethra are rare lesions, and have often been described in boys. The polyps are benign lesion usually lined by a transitional epithelium, but cases of squamous or intestinal metaplasia have been reported. We report a case of a 10 years old boy referred for hematuria and dysuria. The voiding cysto urethrogram revealed a filling defect in the posterior urethra. At cystourethroscopy, a polyp of the posterior urethra was found and resected transurethrally. Histological examination showed a polyp with a fibro muscular core covered by focal gastric metaplasia with fundic gland. To our knowledge this is the first reported case of gastric metaplasia of urethral polyp.

A glycolipid detected in human gastric mucosa with anti-GM2 monoclonal antibody was characterized to be GalNAc beta 1-4[NeuAc alpha 2-3]Gal beta 1-4GlcNAc beta 1-3Gal 1-4Glc-Cer (NGM-1), which was lost in gastric cancer tissue with complementary increase of GM2 sharing the same terminal carbohydrate structure as NGM-1 (Dohi, T., Ohta, S., Hanai, N., Yamaguchi, K., and Oshima, M. (1990) J. Biol. Chem. 265, 7880-7885). The study on differential expression of NGM-1 in gastric fundic mucosa, pyloric mucosa, gastric cancer, and various other tissues indicated that NGM-1 existed specifically in fundic mucosa. The content of GM3 and sialylparagloboside (SPG), which are the substrates for the synthesis of GM2 and NGM-1, respectively, were not significantly different in these tissues. Therefore, the presence of two kinds of beta 1,4GalNAc transferases having different substrate specificity was considered to be critical for the expression of NGM-1 and GM2. The activity of beta 1,4GalNAc transferase which synthesizes GM2 or NGM-1 was determined by detecting the products with specific monoclonal antibodies. The activity of beta 1,4GalNAc transfer to SPG was high in fundic mucosa, while it was absent in pyloric mucosa or cancer. On the other hand, the increased activity of beta 1,4GalNAc transfer to GM3 was observed in cancer tissues and cancer cell lines which were rich in GM2. Our conclusion is that the limited expression of NGM-1 in fundic mucosa and the increase of GM2 in cancer are attributed to two types of beta 1,4GalNAc transferases localized in each region with different substrate specificity; the one in fundic mucosa transfers GalNAc to SPG but not to GM3, and the other one enhanced in cancer transfers GalNAc to GM3 but not to SPG.

Mucous neck cells (MNCs) of the fundic gland are phylogenetically thought to have first appeared in amphibians. We studied the origin and differentiation of MNCs in fundic glands of Xenopus laevis. By means of lectin histochemical methods using Griffonia simplicifolia agglutinin-II (GSA-II), MNCs were detected specifically in fundic glands of adult X. laevis. Mucous granules of MNCs were labeled by GSA-II-colloidal gold (CG) staining. Other cells such as surface mucous cells (SMCs), oxynticopeptic cells (OPCs), and endocrine cells did not react to GSA-II. Ulex europaeus agglutinin-I specifically stained OPCs, but not MNCs and SMCs. During the morphogenetic period of the stomach in metamorphosing larvae, GSA-II reactive cells randomly appeared in various portions of the underdeveloped fundic glands and then rapidly localized in the neck portion. At this time, newly appearing mucous granules of MNC type were labeled by GSA-II-CG. Two types of cells intermediate to MNCs and SMCs and intermediate to MNCs and OPCs were observed in the larval gastric region. Cells intermediate to MNCs and OPCs were also found in adults. In these cells, mucous granules of MNC type were labeled by GSA-II-CG, but mucous granules of SMC type and zymogen-like granules did not react to GSA-II. These observations suggest that GSA-II is a useful marker in studying the differentiation of MNCs and their precursors regardless of species differentiation.

Physiologic studies conducted in rats have demonstrated that afferent fibers of the gastric branch of the vagus nerve increase their firing rate with the intragastric administration of the amino acid glutamate, and the increased firing rate is blocked by the depletion of serotonin (5-HT), administration of the blocker for the serotonin type-3 receptor (SR3), or nitric oxide synthase (NOS). To understand glutamate signaling in the gastric mucosa at the cellular level, we have been studying rats as an animal model using anatomic and immunohistochemical procedures. Our results have indicated that 5-HT-immunoreactive (ir) cells are present in the superficial part of the gastric mucosal epithelium and in the base of the fundic glands, whereas immunoreactivity for SR3 is localized in the neck and its vicinity of the fundic glands. Further, NOS1/neuronal NOS-ir cells with a bipolar shape are located in the lamina propria where a dense network of neuronal cells is present. These results suggest that complex cellular events take place during intragastric glutamate signaling.

The localization of progastricsin was studied in cells of abomasal mucosa from cattle of different ages and feeding regimes and compared to the localization of prochymosin and pepsinogen in the same material by use of an immunofluorescence technique with specific rabbit antibodies. Immunoreactivity for progastricsin was first found in calves at the age of about 45 days in surface mucous cells in the pit of the fundic gland. In older calves and adults, mucous neck cells also produced progastricsin. In the pyloric mucosa, on the other hand, traces of progastricsin immunoreactivity were found in the lower base of the pyloric gland even in newborn calves. When the calves grew older, progastricsin-immunoreactive cells also developed in the pit and later in the neck of the pyloric gland; and the number of these cells in this region increased with age. The development of progastricsin-producing cells seemed to be influenced only by age and not by the feeding of milk to the calves. The ontogeny of progastricsin, prochymosin, and pepsinogen exhibited an interesting pattern in cattle, as they started to be produced at three different ages and gave three different patterns of development in the cells of abomasal mucosa. The number of cells producing prochymosin was closely correlated with milk-feeding, while the development of progastricsin was most related to the age of the calf. The most stable factor during the development of the cells in the abomasum was the number of cells producing pepsinogen.

Development and maturation of pepsinogen 1-producing cells were studied in the gastric fundic mucosa of the mouse by means of light- and electron-microscopic immunocytochemistry using rabbit anti-rat pepsinogen 1-serum. In the adult mouse, secretory granules in mucous neck cells, transitional mucous neck/chief cells and chief cells are immunolabeled. The numerical density of gold particles on zymogen granules is not significantly altered among different stages of maturation of chief cells. In addition, rough endoplasmic reticulum and Golgi complex of these cell types show a weak labeling. In mice from day 16 of gestation to postnatal day 14, mucous neck cells and chief cells cannot be distinguished, but only one type of pepsinogen 1-producing cell, called 'primitive chief cell', is identified in the fundic gland. The intensity of immunoreactivity of secretory granules in primitive chief cells is uniform within an individual cells but varies greatly among different cells. The majority of primitive chief cells contains weakly labeled granules regardless of the maturation stage of cells or of animals. On postnatal day 21, mucous neck, transitional and chief cells are distinguishable, and secretory granules in these cells are intensely immunolabeled as in the adult. These results suggest that pepsinogen 1-production rapidly increases with differentiation of mucous neck and chief cells.

The development of Wistar rat fundic glands was studied using Griffonia simplicifolia agglutinin-IB4 (GSA-IB4) at the light microscopic and electron microscopic levels.In adult rats, GSA-IB4 specifically labeled the intracellular canaliculi and the apical surface on the fundic gland parietal cells, whereas the other sites of these cells were very weakly or rarely labeled.Ontogenic studies revealed that at 18 days of gestation, GSA-IB4 positive reaction was found along the whole cell surface of the cells on the fundic gland and immature intracellular canaliculi of the primitive parietal cells. At 1 day after birth, the positive reaction was restricted to the parietal cells. GSA-IB4 specifically labeled the intracellular canaliculi and the apical cell surface of the parietal cells, but the labeling of the basolateral cell membrane of parietal cells decreased. At the point of weaning, 3 weeks after birth, GSA-IB4 strongly labeled the intracellular canaliculi whereas the basolateral membrane was weakly labeled. This staining pattern did not change basically until adult stage.From these results, it is concluded that the functional maturation of the parietal cells may occur at weaning in spite of their early appearance of morphological characters.