Isolation and Identification of Helicobacter spp. from Canine and Feline Gastric Mucosa

It is known that virtually all healthy adult dogs and cats harbor spiral helicobacters in their gastric mucosa. Three species, Helicobacter felis, Helicobacter bizzozeronii, and Helicobacter salomonis have been isolated in vitro from the gastric mucosa of these animals. The aims of this study were to evaluate the efficacy of an isolation method for canine and feline gastric helicobacters that has been developed at the University of Helsinki; to estimate the prevalence and distribution of these taxa in the samples examined; and to assess the efficacy and validity of an extensive set of standardized conventional phenotypic tests, whole-cell protein profiling, and ultrastructural analysis in identifying the different species isolated from canine and feline gastric mucosa. We cultured 95 and 22 gastric mucosal biopsies from dogs and cats, respectively. Twenty-one H. bizzozeronii strains, 8 H. felis strains, 8 H. salomonis strains, 3 mixed cultures, 2 “Flexispira rappini”-like organisms, and 3 as yet uncharacterized strains were isolated from the dogs, and 3 H. felis strains were isolated from the cats. The methods used here yielded Helicobacter isolation rates of 51% from dogs and 13.6% from cats, which exceed those reported previously. The main difficulties were primary isolation, mixed cultures, and identification to the species level. In the species identification, a detailed morphological examination was found to yield important phenotypic characteristics. A large panel of biochemical and tolerance tests did not clearly differentiate the closely related species H. bizzozeronii, H. felis, and H. salomonis. Highly standardized whole-cell protein profiling was shown to be an excellent method for species identification. Improvements in culture conditions for these bacteria are still needed, especially for cats. A genetic identification method not requiring culture is needed for future studies of these very fastidious helicobacters, as the clinical significance and ecology of these species within the gastric mucosa of the domestic carnivores remain largely unknown.     

Microelectrode Studies of Dog's Gastric Mucosa

In anesthetized dogs, the potentials in the mucous coat and gastic cells were measured with microelectrodes. In the secreting stomach, with isotonic saline in contact with the mucosal surface, the orientation of the initial change in potential difference (PD) was often the same as that of the liquid junction potential between gastric juice and saline (the microelectrode became negative to a reference electrode in the saline) but the magnitude of the change was never more than 11 mv. On the basis of this finding an explanation is offered for the observation that in the secreting stomach replacing isotonic saline with isotonic HCl as the bathing fluid on the mucosal surface, results in a change in the serosal to mucosal PD of only 19 mv, which is 40% less than the liquid junction potential between gastric juice and saline. In the surface epithelial cells of both resting and secreting stomach, multiple levels of potentials were found. For the secreting stomach, the resistance between the interstitial fluid of the pit region and the fluid on the mucosal surface was 55 ohm cm², determined as the change in PD per unit of applied current across stomach. The implications of these findings are discussed with reference to the separate site theory of HCl formation.     

Invasiveness of Helicobacter pylori into Human Gastric Mucosa

Background. Helicobacter pylori has generally been observed only in the gastric mucous layer or in the spaces between gastric mucus -s ecreting cells and not in the gastric epithelial cells or in the lamina propria. The purpose of this study is to determine whether H. pylori invades the gastric mucosa, using an immunoelectron microscopical examination of human gastric mucosa infected with H. pylori.
Materials and Methods. Five hundred gastric antral biopsy specimens were fixed in a periodate-lysin-paraformaldehyde solution, embedded in Lowicryl, sectioned, and examined with a light microscope. One hundred specimens moderately or severely infected with H. pylori were selected and were incubated with polyclonal rabbit anti– H. pylori antibody. The specimens were washed, incubated with 20 nm of colloidal gold–conjugated goat anti–rabbit IgG, stained with uranyl acetate and lead citrate, and observed with a transmission electron microscope.
Results. In one case, a bacterium was observed within the cytoplasm of a gastric mucus -s ecreting cell; in another case, a few bacteria were observed within the cytoplasm of a stromal cell in the lamina propria. The bacteria could be differentiated from degenerated intracellular organelles by gold particles attached to the bacteria.
Conclusion. H. pylori rarely invade the lamina propria and gastric cells.     

花生油对酒精所致胃粘膜损伤的保护作用

着重研究了花生油对无水酒精所引起的大白鼠胃粘膜损伤的保护作用,并对花生油作用的有效部位和机制作了初步探讨。     

Reactive Nitrogen Species Mediate DNA Damage in Helicobacter pylori-Infected Gastric Mucosa

Background:  Reactive oxygen species (ROS) and reactive nitrogen species (RNS) can play an important role in cellular injury and carcinogenesis of gastric epithelial cells infected with Helicobacter pylori . 8-OH-deoxy guanosine (8-OHdG) and 8-nitroguanine (8-NG) are markers for ROS- and RNS-mediated DNA oxidation, respectively. In this study, RNS-mediated DNA damage in gastric mucosa was observed directly using a newly developed antibody to 8-NG to clarify how H. pylori infection causes nitrative DNA damage to gastric epithelial cells.
Methods:  Immunohistochemistry with anti-8-OHdG and anti-8-NG antibodies was performed on gastric tissue samples from 45 patients (25 men and 20 women) with H. pylori -positive gastritis and 19 patients (11 men and 8 women) exhibiting successful H. pylori eradication. Histologic factors for gastric mucosal inflammation were graded according to the guidelines of the Updated Sydney system.
Results:  In corpus mucosa, 8-OHdG and 8-NG production were significantly associated with the degree of glandular atrophy, infiltration of chronic inflammatory cells and intestinal metaplasia in the glandular epithelial cells. Successful H. pylori eradication resulted in a significant reduction of chronic inflammatory cell infiltration and neutrophilic activity. Mean 8-OHdG production was lower after H. pylori eradication in both corpus and antral mucosa ( p  = .022 and .049, respectively). However, the reduction in 8-NG exhibited was more pronounced than the reduction of 8-OhdG ( p  = .004 and .007, respectively).
Conclusions:  Helicobacter pylori infection can induce inflammatory cells infiltration, which evokes DNA damage of gastric epithelial cells through ROS and RNS production. 8-NG might be a more sensitive biomarker than 8-OHdG for H. pylori -induced DNA damage in gastric mucosa.     

Concomitant Staining of Mast and Parietal Cells in Human Gastric Mucosa

A simple technique for concomitant staining of mast and parietal cells in the same section is described. Mast cells were stained by alcian blue or astra blue in methanol-formalinacetic acid fixed biopsies of gastric mucosa. Parietal cells were visualized by Dolichos biflorus lectin binding.     

人胃黏膜上皮细胞与胃癌细胞间酪氨酸磷酸化的比较蛋白质组学研究

比较人正常胃黏膜上皮细胞GES-1与人胃癌细胞SGC-7901间酪氨酸磷酸化蛋白质的差异,筛选差异磷酸化蛋白质分子,为揭示胃癌发生发展的分子机制提供新的理论依据.采用免疫沉淀方法从人胃黏膜上皮细胞GES-1与人胃癌细胞SGC-7901总蛋白质中免疫沉淀出酪氨酸磷酸化蛋白质,用SDS-PAGE和二维凝胶电泳技术分离沉淀出的酪氨酸磷酸化蛋白质,银染,差异蛋白点进行胶内酶解,采用MALDI-TOF/TOF-MS质谱进行差异蛋白质鉴定.结果显示获得了7个差异酪氨酸磷酸化蛋白质,这些蛋白质涉及细胞骨架、细胞调控等.通过比较正常胃黏膜上皮细胞与胃癌细胞内酪氨酸磷酸化蛋白质的差异,筛选获得7个差异酪氨酸磷酸化蛋白质分子,有助于深入研究胃癌发生发展的分子机制,进而为胃癌的早期诊断和防治提供新的理论依据和作用靶标.     

人胃粘膜乳酸杆菌与幽门螺杆菌感染的相关性

目的:探讨胃内正常菌群乳酸杆菌对幽门螺杆菌(Helicobacter pylori,HP)的影响。方法:51例胃粘膜活检标本均取自于行胃镜检查的胃炎患者,分离培养乳酸杆菌,通过扩增其16S rRNA基因并测序来鉴定乳酸杆菌的种类;胃炎程度及活动度的分类依据悉尼分类系统,运用改良Gimesa染色鉴定HP感染。结果:胃粘膜中共分离出9种乳酸杆菌,分离阳性率为49.0%;乳酸杆菌阳性病人与阴性病人的HP感染率、胃炎程度的差异及胃炎活动度的差异均无统计学意义(P>0.05);HP阳性病人的胃炎程度较HP阴性病人更严重(P<0.05);有益生菌作用的乳酸杆菌与非益生菌类乳酸杆菌的HP感染率差异无统计学意义(P>0.05)。结论:胃内乳酸杆菌的存在对HP感染无影响。     

Role of L-Arginine in Ibuprofen-induced Oxidative Stress and Neutrophil Infiltration in Gastric Mucosa

It has been proposed that neutrophil and oxygen dependent microvascular injuries may be important prime events in gastrointestinal (GI) toxicity of nonsteroidal antiinflammatory drugs (NSAIDs). l-arginine (l-ARG) is an essential amino acid which participates in many important biochemical reactions associated to the normal physiology of the organism. In these experimentations, we studied the role of l-ARG, aminoacid precursor of NO synthesis, on ibuprofen (IB) induced gastric lesions, and also on the inflammatory and oxidative mechanisms related to mucosal damage. Oral administration of IB (100 mg kg^-1), produced severe damage on gastric mucosa, which was more important after 6 h test-period, and was accompanied by a significant increment in myeloperoxidase (MPO) activity, as index of neutrophil activation, as well as lipid peroxidation (LP) levels and xanthine oxidase (XO) activity. However, no changes were observed in total mucosal glutathione (tGSH), nor glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity. Simultaneous treatment with equimolar doses of l-ARG (oral and i.p.), considerably reduced the number and intensity of lesions, and at the same time (6 h) the maximum protection was also observed. In addition, l-ARG inhibited the IB-induced LP and XO enhancement, but did not produce changes in leukocyte infiltration, tGSH, GSH-Px and SOD activity. These findings suggest that (1) l-ARG protective effect on gastric mucosa against IB-induced mucosal lesions could be explained by a local effect and also might be due to the systemic action of the aminoacid; (2) the active oxygen species, derived both from XO and activated neutrophils, could play a role in the pathogenesis of gastric injury induced by IB, (3) l-ARG exhibit a protective effect against IB-induced mucosal damage, probably through the inhibition of oxidative stress derived via xanthine-XO, but it does not block the oxygen free radical production through polymorphe nuclear leukocytes.     

Remodeling of the Residual Gastric Mucosa after Roux-En-Y Gastric Bypass or Vertical Sleeve Gastrectomy in Diet-Induced Obese Rats

Whereas the remodeling of intestinal mucosa after bariatric surgeries has been the matter of numerous studies to our knowledge, very few reported on the remodeling of the residual gastric mucosa. In this study, we analyzed remodeling of gastric mucosa after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) in rats. Diet-induced obese rats were subjected to RYGB, VSG or sham surgical procedures. All animals were assessed for food intake, body-weight, fasting blood, metabolites and hormones profiling, as well as insulin and glucose tolerance tests before and up to 5 weeks post-surgery. Remodeling of gastric tissues was analyzed by routine histology and immunohistochemistry studies, and qRT-PCR analyses of ghrelin and gastrin mRNA levels. In obese rats with impaired glucose tolerance, VSG and RYGB caused substantial weight loss and rats greatly improved their oral glucose tolerance. The remaining gastric mucosa after VSG and gastric pouch (GP) after RYGB revealed a hyperplasia of the mucous neck cells that displayed a strong immunoreactivity for parietal cell H⁺/K⁺-ATPase. Ghrelin mRNA levels were reduced by 2-fold in remaining fundic mucosa after VSG and 10-fold in GP after RYGB. In the antrum, gastrin mRNA levels were reduced after VSG in line with the reduced number of gastrin positive cells. This study reports novel and important observations dealing with the remaining gastric mucosa after RYGB and VSG. The data demonstrate, for the first time, a hyperplasia of the mucous neck cells, a transit cell population of the stomach bearing differentiating capacities into zymogenic and peptic cells.     

Back Diffusion of Hydrogen Ions across Gastric Mucosa of Patients with Gastric Ulcer and Rheumatoid Arthritis

Ionic permeability of the gastric mucosa was measured in six patients with an acute exacerbation of severe generalized rheumatoid arthritis receiving either aspirin and prednisone or aspirin and indomethacin as therapy. The results were compared with those in four patients with benign gastric ulcer and nine normal subjects. Compared with controls H⁺ concentration was decreased and Na⁺ concentration increased while corrected H⁺ flux out of the lumen and Na⁺ flux into the lumen were significantly increased in the patient groups, indicating increased mucosal permeability. Abnormality of the gastric mucosal barrier persisted in two patients despite healing of their ulcers. Mucosal permeability of patients with rheumatoid arthritis and gastric ulcer did not differ significantly from one another. One rheumatoid patient with a gastric ulcer showed no difference in mucosal permeability to that of the other rheumatoid patients. These studies suggest that increased H⁺ ion loss contributes to the apparent hyposecretion of acid in patients gastric ulcer; persistence of an abnormal gastric mucosal barrier to H⁺ ions may explain the high recurrence rate of gastric ulcers; and an abnormal gastric mucosal barrier may be a precursor to gastric ulceration in rheumatoid arthritis.     

A Combined Stain for Identifying Epithelial Cells of the Gastric Mucosa

New techniques are proposed for differentiating each type of gastric epithelial cell in the same tissue section. The techniques combine the following stains: A) paradoxical concanavalin A staining (PCS) to identify mucous neck cells, B) periodic acid Schiff-concana-valin A staining to distinguish mucous neck cells from surface mucous cells, and C) a modified Bowie's stain to demonstrate zymogen granules of chief cells. Feulgen hydrolysis preceding the Bowie stain was found to remove most of the nonspecific coloration encountered with the original Bowie method. The results obtained by the new sequences were as follows: 1) Feulgen hydroIysis-PCS-Bowie staining: mucous neck cells stained brown and chief cell zymogen granules deep blue. The other mucin-secreting cells remained unstained; 2) Feulgen hydrolysis-PAS-concanavalin A-Bowic staining: mucous neck cells stained brown, zymogen granules stained deep blue to purplish blue and surface mucous cells stained purplish red.