[Systematic review of methodological quality and reporting quality in gastric cancer screening guidelines]

Objective: To systematically evaluate the quality of gastric cancer screening guidelines/recommendations, and provide a reference for the update of gastric cancer screening guidelines/recommendations in China. Methods: "guidelines/consensus/specifications/standards" , "stomach/gastric tumors" , "screening/diagnosis" , "guideline/recommendation" , "gastric cancer/gastric tumor," "early detection of cancer/screening" were searched as keywords in PubMed, Embase, Web of knowledge, China Knowledge Network, Wanfang, China Biomedical Literature Database, and Cochrane Library, as well as the US Preventive Services Working Group, the American Cancer Society, the International Agency for Research on Cancer, the Australia Cancer Council and the International Guide Collaboration Network at the end of July 2018. The inclusion criteria were independent guidelines/recommendation documents for gastric cancer screening. The exclusion criteria were guideline abstracts, interpretation and evaluation literature, duplicate publications, updated original guidelines, and clinical treatment or practice guidelines for gastric cancer. The language was limited to Chinese and English. The European Guide to Research and Evaluation Tools (AGREE Ⅱ) and Practice Guideline Reporting Standard (RIGHT) for Gastric Cancer Screening Guidelines/Recommendations were used to compare and evaluate the quality and reporting standard of gastric cancer screening guidelines/recommendations. Results: A total of five guides/recommendations were included. The results of the AGREE Ⅱ quality evaluation showed that the overall quality of five guides/recommendations was different, including one recommended for "A", one for "B", and three for "C". Each guide/recommendation scored higher in the scope and purpose, clarity, and scores were more significant in the areas of rigor and independence. In the participants, the application field scores were generally low. The RIGHT evaluation results showed that the quality of five guides/recommendations should be improved. The six items with poor report quality were background, evidence, recommendations, review and quality assurance, funding and conflict of interest statement and management, and other aspects. Conclusion: The quality of the included gastric cancer screening guidelines/recommendations is generally low, and the standardization should be strengthened.

Chronic ethanol feeding alters the epithelial cell proliferation and apoptosis in rat gastric mucosa

We developed a chronic drinking rat model to investigate the long-term effects of ethanol feeding on cell proliferation and apoptosis in rat stomach. Adult male Sprague-Dawley (SD) rats received either an isocaloric control or drinking water containing 6% (v/v) ethanol as their only water intake for 1, 3, 7, 14 and 28 days. At the end of each feeding period, animals were sacrificed and the stomach was dissected for the sample preparation. The cell proliferation and apoptosis in gastric mucosa of rats in different groups were analyzed by flow cytometer, immunohistochemistry and computer image analysis. In the flow cytometric study, compared with the control, the cell apoptosis in gastric mucosa of the rats was enhanced during the exposure to the ethanol in 3rd to 28th day. Otherwise the cell proliferation was increased in 3rd to 14th days, and decreased in 28th days, respectively. The results were confirmed by immunohistochemistry and computer image analysis studied. This finding suggested that short-term chronic adequate alcohol intake may enhance the cell turnover of gastric mucosa. Long-term stimulus with the low concentration ethanol may cause the impairment of the cell turnover function of the gastric mucosa and may be one of the mechanisms underlying the gastric pathology associated with alcohol abuse.

Immunocytochemistry and in situ hybridization studies of pepsinogen C-producing cells in developing rat fundic glands

The ontogeny of pepsinogen C-producing cells in rat fundic glands was studied by means of light and electron microscopy using an antiserum raised against a synthetic peptide based on rat pepsinogen C. To confirm the immunocytochemistry results, the expression of rat pepsinogen C messenger RNA (mRNA) in the fundic gland was also examined by in situ hybridization using a digoxigenin-labeled RNA probe. In adult rats, pepsinogen C was produced by chief cells, mucous neck cells, and intermediate mucopeptic cells. Pepsinogen C-producing cells appeared in embryos as early as 18.5 days' gestation. The development of these cells could be classified into four stages: (1) 18.5 days' gestation to 0.5 days after birth; (2) 0.5 days to 2 weeks after birth; (3) 3-4 weeks after birth; (4) 4-8 weeks after birth. In embryos and young animals, pepsinogen C-producing cells were mucopeptic cells. By 4 weeks after birth, mucous neck cells could be distinguished morphologically. The maturation stages of the chief cells could be traced by electron microscopy along the longitudinal axis of the rat fundic gland by double-staining with anti-pepsinogen C antibody and periodic acid-thiocarbohydrazide-silver proteinate. Positive reactions for pepsinogen C and pepsinogen C mRNA expression were detected in mucous neck cells. Therefore, we conclude that mucous neck cells are precursor cells of chief cells. Mucous neck cells, intermediate cells, and chief cells are in the same differentiating cell lineage.

Proliferation and migration kinetics of stem cells in the rat fundic gland

The proliferation and migration of stem cells in the developing and adult rat fundic gland have been studied using BrdU immunohistochemistry and BrdU-GSA II (Griffonia-simplicifolia agglutinin-II) double staining. In the developing rat fundic gland, stem cells were first scattered throughout all levels of the epithelia and then concentrated in the depth of the pits. With the elongation and maturation of the fundic glands, stem cells left the gland base and moved upward. By 4 weeks after birth, the development of the fundic gland was completed and stem cells were confined to a narrow proliferative zone in the isthmus, reaching the adult distribution pattern. In the adult rat fundic gland, stem cells in the isthmus differentiated and migrated upward and downward, replacing the surface mucous cells and glandular cells respectively. For upward migration, it took about one week for stem cells to migrate from the isthmus to the surface. For downward migration, it took about two weeks for stem cells to migrate from the isthmus to the neck, and it took 30-36 weeks to reach the gland unit's blind end. Finally stem cells were lost at the deepest level of the glands. The results obtained by simple topographical distribution in the present experiment agreed well with those obtained by quantitative analysis, suggesting the usefulness of BrdU immunohistochemistry for cell kinetic studies.

Cationic colloidal gold staining of acidic glycoconjugates in mouse Paneth cells

The acidic glycoconjugates of mouse ileum Paneth cells were examined with the aid of light and electron microscopy, using cationic colloidal gold (CCG) as a probe. Specimens of mouse ilea were fixed in half-strength Karnovsky's fixative and embedded in Lowicryl K4M resin. Semithin and ultrathin sections were cut of examination with light and electron microscopy, respectively. Examination of the sections using light microscopy revealed the positive staining of CCG at pH 1.0 and pH 2.5, which was detected at the rim of secretory granules and at the supranuclear regions of the Paneth cells. At pH 4.0, in addition to staining of the secretory granule rim, weak staining was observed in the granule core. At pH 7.2, the cytoplasm other than secretory granules exhibited positive CCG staining. Examination of the sections using electron microscopy, at pH 1.0, the trans lamellae of the Golgi apparatus, the rim of the secretory granules, and lysosomes were labeled selectively by CCG. At pH 2.5, labeling was also discernible over the same structures in the cells. However, at this pH, the labeling intensity was stronger than that at pH 1.0, due to the dual labeling of sulfated and sialylated glycoconjugates in these structures. At pH 4.0, the Golgi apparatus, rims and cores of secretory granules and ribosomes were labeled. Lysosomes and nuclei were also positively stained. At pH 7.2, the rims of secretory granules were not stained. The present results indicate that the CCG method gives good resolution and contrast when applied to staining, and therefore is useful for the specific staining of glycoconjugates such as sulfated, sialylated and phosphated glycoconjugates for light and electron microscopy.

Ontogeny of proliferative cells in the rat fundic gland

The ontogeny of proliferative cells in the rat fundic gland was studied using bromodeoxyuridine (BrdU) immunohistochemistry from day 17.5 of gestation to 8 weeks after birth. This ontogenic process is divided into 4 stages. (1) The late fetal period extending to 0 day of birth: Proliferative cells were scattered throughout all levels of the stratified epithelium in the earliest stage (day 17.5-18.5 of gestation). With the appearance of a primitive gastric pit at day 19.5 of gestation, proliferative cells were more numerous at the base of the fundic gland. Proliferative cells were concentrated in the gland base and were rarely seen in the epithelial surface from day 21.5 of gestation onwards. (2) One day to 2 weeks after birth: As fundic gland growth proceeded, proliferative cells remained concentrated in the gland base. (3) Two to 4 weeks after birth: Proliferative cells left the gland base and moved upward to reach the adult location in the isthmus. (4) Four to 8 weeks after birth: The development of the fundic gland was complete and proliferative cells remained in a narrow proliferative zone in the isthmus.