Association between common genetic variants in pre-microRNAs and gastric cancer risk in Japanese population

Background: Common single‐nucleotide polymorphisms (SNPs) in microRNAs (miRNA) have been shown to be associated with susceptibility to several human cancers. We evaluated the associations of three SNPs (rs11614913, rs2910164, and rs3746444) in pre‐miRNAs (miR‐196a2, miR‐146a, and miR‐499) with the risk of gastric cancer (GC) and peptic ulcer diseases, and with the severity of Helicobacter pylori‐induced gastritis in Japanese population. Methods: The rs11614913 (C>T), rs2910164 (G>C), and rs3746444 (A>G) SNPs were genotyped in 552 GC, and 697 non‐cancer subjects, including 141 gastric and 73 duodenal ulcer, and 483 non‐ulcer subjects. The degree of histologic gastritis was classified according to the updated Sydney System, and the serum pepsinogen levels were measured in selected 579 and 204 cases. Results: The rs2910164 CC genotype held a significantly higher risk of GC when compared to non‐cancer subjects (adjusted odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.02–1.66, p =.03). Similarly, the rs2910164 C carrier was associated with higher risk of GC when compared to both non‐cancer and non‐ulcer subjects (OR = 1.39, 95%CI = 1.00–1.93, p =.05, adjusted OR = 1.57, 95%CI = 1.09–2.27, p =.016, respectively). The rs2910164 CC genotype was associated with non‐cardia and upper third, diffuse type and advanced stage GC. The rs11614913 TT genotype was associated with higher degree of mononuclear cell infiltration (score 0–1 vs 2～, adjusted OR = 1.62, 95%CI = 1.05–2.49, p =.03). Conclusions: The rs2910164 (G>C) SNP in the miR‐146a is associated with susceptibility to GC. In addition, the rs11614913 (C>T) SNP in the miR‐196a2 is associated with the degree of H. pylori‐induced mononuclear cell infiltration.     

Role of endogenous nitric oxide in mucosal defense of inflamed rat stomach following iodoacetamide treatment

Nitric oxide (NO) plays a role in regulating the mucosal integrity of the stomach. However, its part in the mucosal defense of the inflamed stomach remains unclear. In the present study, we examined the effects of various NO synthase (NOS) inhibitors on gastric ulcerogenic and acid secretory responses following daily exposure of the stomach to iodoacetamide and investigated the role of each NOS isozyme in gastric protection from subchronic mucosal irritation. Gastric mucosal irritation was induced in rats by addition of 0.1% iodoacetamide to drinking water, and the gastric mucosa was examined on the 6th day. L-NAME (a nonselective NOS inhibitor: 20 mg/kg) or aminoguanidine (a selective iNOS inhibitor: 20 mg/kg) was given s.c. twice 24 h and 3 h before the termination of iodoacetamide treatment. Giving iodoacetamide in drinking water for 5 days produced minimal damage in the stomach with an increase in myeloperoxidase (MPO) activity and lipid peroxidation. Iodoacetamide treatment up-regulated the expression of iNOS mRNA and NO production in the stomach, without affecting nNOS expression. Both L-NAME and aminoguanidine markedly aggravated gastric lesions induced by iodoacetamide treatment, with a further enhancement in MPO activity and lipid peroxidation. Basal acid secretion as determined in pylorous-ligated stomachs was decreased following iodoacetamide treatment, but the response was significantly restored by both L-NAME and aminoguanidine. These results suggest that endogenous NO derived from both cNOS and iNOS is involved in mucosal defense of the inflamed stomach, partly by decreasing acid secretion, and contributes to maintaining mucosal integrity under such conditions.     

Effects of pH on the interaction of ligands with the (H+ + K+)-ATPase purified from pig gastric mucosa

The effects of K⁺, Na⁺ and ATP on the gastric (H⁺ + K⁺)-ATPase were investigated at various pH. The enzyme was phosphorylated by ATP with a pseudo-first-order rate constant of 3650 min^?1 at pH 7.4. This rate constant increased to a maximal value of about 7900 min^?1 when pH was decreased to 6.0. Alkalinization decreased the rate constant. At pH 8.0 it was 1290 min^?1. Additions of 5 mM K⁺ or Na⁺, did not change the rate constant at acidic pH, while at neutral or alkaline pH a decrease was observed. Dephosphorylation of phosphoenzyme in lyophilized vesicles was dependent on K⁺, but not on Na⁺. Alkaline pH increased the rate of dephosphorylation. K⁺ stimulated the ATPase and p-nitrophenylphosphatase activities. At high concentrations K⁺ was inhibitory. Below pH 7.0 Na⁺ had little or no effect on the ATPase and p-nitrophenylphosphatase, while at alkaline pH, Na⁺ inhibited both activities. The effect of extravesicular pH on transport of H⁺ was investigated. At pH 6.5 the apparent K_m for ATP was 2.7 μM and increased little when K⁺ was added extravesicularly. At pH 7.5, millimolar concentrations of K⁺ increased the apparent K_m for ATP. Extravesicular K⁺ and Na⁺ inhibited the transport of H⁺. The inhibition was strongest at alkaline pH and only slight at neutral or acidic pH, suggesting a competition between the alkali metal ions and hydrogen ions at a common binding site on the cytoplasmic side of the membrane. Two H⁺-producing reactions as possible candidates as physiological regulators of (H⁺ + K⁺)-ATPase were investigated. Firstly, the hydrolysis of ATP per se, and secondly, the hydration of CO₂ and the subsequent formation of H⁺ and HCO₃^?. The amount of hydrogen ions formed in the ATPase reaction was highest at alkaline pH. The H⁺/ATP ratio was about 1 at pH 8.0. When CO₂ was added to the reaction medium there was no change in the rate of hydrogen ion transport at pH 7.0, but at pH 8.0 the rate increased 4-times upon the addition of 0.4 mM CO₂. The results indicate a possible co-operation in the production of acid between the H⁺ + K⁺-ATPase and a carbonic anhydrase associated with the vesicular membrane.     

HpD-激光对离体培养人胃癌细胞杀伤效应的电镜观察

本文应用扫描和透射电镜观察了HpD-激光光敏作用对人胃癌MGc 80-3细胞超微结构的损伤效应。结果表明,光敏作用可以使多种细胞器结构受到损伤:(1) 使细胞表面微绒毛减少,出现大量泡状突起,最后质膜破裂、崩解;(2) 使线粒体肿胀、嵴被破坏,随后整个线粒体空泡化;(3) 使高尔基囊扩张,高尔基液泡和高尔基小泡形态变得极不规则;(4) 使核膜破裂,核仁崩解,染色质凝聚。不同的细胞以及不同的细胞器光敏损伤的时间和程度并不相同。本文讨论了损伤的不同步性与临床治疗不彻底和复发之间的关系。     

The effects of gastric inhibitory polypeptide (GIP) on the release of anterior pituitary hormones

Several members of the secretin family of hormones have been demonstrated to alter anterior pituitary hormone secretion. Here we report the action of gastric inhibitory polypeptide (GIP) on gonadotropin and somatotropin release. Intraventricular injection of 1 microgram (0.2 nmole) GIP (2.5 microliters) produced a significant decrease in plasma FSH at 30 (p less than 0.02) and 60 min after its injection (p less than 0.01). The FSH-lowering effect of a higher dose of 5 micrograms (1 nmole) of GIP was already developed at 15 min (p less than 0.01) and was prolonged until the end of the experiment (60 min, p less than 0.05). No change in plasma LH was detected at any time during the experimental period. If 5 micrograms of estradiol-benzoate were given SC 48 hr prior to experiment, the initial values of FSH and LH were markedly decreased. In these animals GIP failed to influence plasma FSH and LH. When dispersed anterior pituitary cells from OVX rats were cultured overnight and incubated in vitro with GIP, the peptide was found to induce both FSH and LH release. Highly significant release occurred with the lowest dose tested of 10(-7) M and there was a dose-response effect for both hormones. The slope of the dose-response curve was similar for both FSH and LH release. GIP was less potent than LHRH which produced a greater stimulation of both FSH and LH release at a dose of 10(-9) M than did 10(-7) M GIP. The two peptides had an additive effect on the release of both FSH and LH.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electron-microscopic studies on the physiological cell loss in the gastric mucosa of the golden hamster

Summary Fine-structural aspects of physiological cell loss in the gastric mucosa of the golden hamster were observed. As the surface mucous cell ascends along the gastric pit, the cell becomes taller and funnel-like in shape. The interfoveolar cell located at the superficial portion of the gastric pit has many lysosomes and a few lipid droplets in the cytoplasm. The nucleus moves toward the upper region of the cytoplasm, while the Golgi apparatus moves downward toward the infranuclear region. After the rupture of the apical plasma membrane takes place, the lateral and basal plasma membranes of this cell remain in spite of loss of the cell contents. Between the basal plasma membrane of the interfoveolar cell and the capillary endothelium is a thick connective tissue layer characterized by densely packed collagen fibrils. The remaining basal and lateral plasma membranes of the ruptured cell and the thick underlying collagenous layer might play a role in protecting the tissue from potential damage induced by the physiological cell loss.This study was supported in part by a grant from the Research Fund of the Ministry of Education, Science and Culture, Japan.     

Taenia taeniaeformis: Gastrointestinal hyperplasia in chronically infected rats

Hyperplastic pathological changes in the gastrointestinal tract and serum gastrin levels were measured at postmortem in rats given long-term infections with metacestodes of Taenia taeniaeformis. Stomach weights were greater than in controls from the beginning of the experiment at 63 days postinfection (DPI) onward, and generally reached highest levels (>16 g) in the more chronically infected rats (up to 368 DPI). Gross and histological evidence of papillary hyperplasia of gastric mucosal cells increased with duration of infection. Intestinal weights also increased with time, but to a much lesser degree than those of the stomachs. These changes were sustained throughout the period of study, and were associated with significant elongation of villi and increased mucosal crypt depth, especially in the duodenum. In the most chronically infected rats multiple cystic dilatations of crypts occurred, and within them accumulated masses of mucus and necrotic cells often became calcified. Villi, sometimes over 1 mm in length, became club-like and frequently fused together. Mucosal mast cell (MMC) numbers in the small intestine were significantly higher than in controls throughout infection. Hyperplastic changes were detected inconsistently in the colonic mucosa, but there were no effects on the esophagus. Splenomegaly was a constant finding in infected rats, which also showed an earlier onset of thymic atrophy than normal age-matched controls. Serum gastrin levels were elevated in all affected rats at 5 months postinfection, but by the end of the first year some animals had normal gastrin levels, even though they showed severe hyperplastic gastroenteropathy at necropsy. Attempts to induce changes in gastric and intestinal weights, MMC numbers, or serum gastrin by the serial inoculation of extracts or in vitro products of T. taeniaeformis strobilocerci were unsuccessful. Surgical implantation of strobilocerci intraperitoneally also produced no measurable changes in these parameters. The results suggest that the hyperplastic stimulus provided by T. taeniaeformis is sustained for many months, and that there is a gradient of responsiveness in gastrointestinal tissues, declining from the glandular stomach mucosa posteriorly. The stimulus may be augmented by endogenous gastrin, but this hormone is not necessary for maintenance of hyperplastic changes. Our failure to induce changes in vivo artificially suggests that more subtle criteria, perhaps involving in vitro influences on gastric or intestinal cell turnover, will be necessary to establish if the parasite exerts its effects on host cells directly or indirectly.     

Fine structure of the gastric epithelium of the ascidian Botryllus schlosseri. Mucous,endocrine and plicated cells

Summary The following five cell types have been recognized and defined on the basis of their fine structure in the gastric epithelium of B. schlosseri: vacuolated and zymogenic cells (described in a previous paper); ciliated mucous, endocrine and plicated cells. The ciliated mucous cells are distributed at the apex and the bottom of the gastric folds and along the dorsal groove. The mucus droplets appear to form from the Golgi complex as secretory granules of variable density and texture, which are released from the cell after fusion of their membranes with the apical plasma membrane. Holocrine or apocrine secretion has not been observed. The endocrine cells are scattered and are characterized by electron dense granules, especially numerous in the basal region of the cell. Finally, the plicated cells, present in the pyloric caecum, show rod-like microvilli, a well developed Golgi complex and abundant, deep infoldings of the basal plasma membrane, which are associated with numerous mitochondria. The possible role of the gastric cell types is discussed taking into account information concerning morphologically similar cells in other animals, as well as previously reported data on the biochemistry and physiology of digestion and excretion in ascidians.The authors are grateful to Mr. G. Tognon for technical help and to the Staff of the Stazione Idrobiologica di Chioggia for their assistance in collecting material. Work supported by a C.N.R. Grant from the Istituto di Biologia del Mare, Venezia, Contract n. 71.00396/04.115.542.     

Ultrastructure and cytochemistry of the gastric mucosa of a reptile,Tiliqua scincoides

Summary The gastric mucosa of a reptile, the lizard Tiliqua scincoides, has been examined by light and electron microscopy. The gastric pits lead into glands that are extensively coiled in the proximal stomach but become progressively shorter and straighter in the distal stomach. The following epithelial cell types have been identified: (i) Surface mucous cells (SMC) line the entire lumenal surface as well as the pits. They contain mucus granules that stain with periodic acid-Schiff and, like the granules of mammalian SMC, commonly contain an electron dense core that appears not to be mucus (periodic acid-chromic acid-silver methenamine nonreactive). (ii) Glandular mucous cells are present in glands throughout the mucosa. They are probably homologous with the mucous neck and antral gland cells of mammals; like SMC their mucus granules contain nonglycoprotein cores. (iii) Oxynticopeptic cells (OPC) are the predominant cell type in the proximal glands but become infrequent distally. Their fine structure resembles that of OPC in other nonmammalian vertebrates, with features like those of both parietal cells and zymogen cells of mammals, (iv) Endocrine cells of three different types have been identified. Two of these show close similarities to the EC and ECL cells of mammals.The authors thank Mrs. D. Flavell for technical assistance. This study was supported by a grant from the Clive and Vera Ramaciotti Foundations     

Distribution of the glio-interstitial system in molluscs

Summary Ten hamsters received repeated injections of ³H-thymidine for 4 days and were allowed to survive for 7, 28, 42 and 100 days. Changes in spatial distribution of the labelled cells and in labelling indices of each cell line in the gastric glands were studied at various days after ³H-thymidine injections, and the fate of the mucous neck cell, the replacement of the chief cell and the mode of cell migration were discussed.After 4 days of repeated injections of ³H-thymidine, the labelled parietal cells and the mucous neck cells were concentrated at the neck area. Starting from the neck area, they migrated an average of 3 micra downwards per day. By 42 days, they reached the middle level of the glands, where the labelled mucous neck cells decreased but the labelled chief cells increased in number. The differentiation of the chief cell then appears to take place at the middle level of the glands through transformation of the migratory mucous neck cells. After 4 days of the labelling, about 1.8% of the chief cells located in the lower part of the glands was found to undergo in situ replication. This indicates that the renewal of this cell type is partly assured by its own mitotic activity.The foveolar cell — the future surface epithelium — seems to migrate upwards along the long axis of the glandular tubule in the pipe line system, which means first produced, first migrates. After migrating out from the neck area, the parietal cell and the mucous neck cell (the future chief cell) take an average of 200 days to reach the lower end of the glands. In the process of migration, however, the cells produced contemporaneously at the neck area became scatteringly spread from the neck towards the bottom of the gland. The time required for the newly-formed cells to reach the lower end of the gland varied between 100 and 300 days. In the gastric glands the cells first produced at the neck area do not first reach the lower end of the glands. This mode of random migration is referred to as the stochastic flow system. As one of the probable factors which disturb the pipe line flow of downward cell migration, cellular movements perpendicular to the long axis of the glandular tubule were suggested to occur at random at an any level of the gastric glands.Supported by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture, Japan