[PI3K p85alpha gene silencing by RNA interference promotes 5-fluorouracil-induced apoptosis of colorectal cancer LoVo cells].

OBJECTIVE: To explore the effect of PI3K p85alpha gene silencing on the 5-fluorouracil (5-FU)-induced apoptosis of colorectal cancer cells. METHODS: The PI3K p85alpha/RNAi transfected cells (PI3K p85alpha/RNAi-LoVo) were cultured in RPMI 1640 supplemented with 10% fetal calf serum and 500 microg/ml G418. The 50% inhibitory concentration (IC50) values of 5-FU (0.000625, 0.00125, 0.005, 0.01, 0.02, 0.04, 0.08, 0.16, 0.32 micromol/ml) were evaluated by MTT assay. Mitochondrial membrane potential was detected by JC-1 fluorescence, and Western blotting was used to analyze the expression of apoptotic proteins Bcl-6 and Bim. RESULTS: Compared with the untransfected LoVo cells, PI3K p85alpha/RNAi-LoVo showed obviously decreased IC(50) of 5-FU (P=0.000). The mitochondrial membrane potential of PI3K p85alpha/RNAi-LoVo cells was significantly lower than that of LoVo cells, suggesting that silencing PI3K p85alpha expression increased the sensitivity of LoVo cells to 5-FU. The expression of apoptotic protein Bcl-6 and Bim were significantly higher in PI3K p85alpha/RNAi-LoVo cells treated with 5-FU than LoVo cells (P=0.000). CONCLUSION: PI3Kp85alpha gene silencing can significantly promote 5-FU-induced apoptosis of colorectal LoVo cells.

[Effects of epigallocatechin-3-gallate on the proliferation of colonic cancer cell line SW620 and PAK1 gene expression].

OBJECTIVE: To investigate the effects of epigallocatechin-3-gallate (EGCG) on the proliferation of SW620 cells and the expression of PAK1 gene. METHODS: Human colonic cancer cell line SW620 was treated with EGCG at 40, 60 and 80 micromol/L and cultured in RPMI 1640 medium for 0, 24, 48 and 72 h. The proliferation of SW620 cells was observed by MTT assay before and after EGCG treatment, and the expression of PAK1 protein was observed by Western blotting. RESULTS: SW620 cells treated with EGCG displayed a slowed growth in comparison with the control cells, and the growth rate decreased with the increase of EGCG concentration. PAK1 protein expression was lowered in SW620 cells after EGCG treatment for 48 h. CONCLUSION: EGCG can inhibit the proliferation and partially reduce the expression of PAK1 protein in SW620 cells.

[Effect of p21-activated kinase-1 on the invasiveness of colorectal carcinoma cells in vitro].

OBJECTIVE: To observe the effect of p21-activated kinase-1 (PAK1) gene transfection on the invasiveness of human colorectal carcinoma SW480 cells in vitro. METHODS: SW480 cells in routine culture were transfected with the recombinant plasmid EGFP-C1/PAK1 via Lipofectamine(TM) 2000. The expression of PAK1 protein in SW480 cells was detected using Western blotting, and the changes of the invasiveness of SW480 cells were evaluated using Boyden chamber invasion assay. RESULTS: Forty-eight hours after transfection with pEGFP-C1/ PAK1, the PAK1 protein expression increased significantly in comparison with those in negative and vector control groups. The invasiveness of the SW480 cells was significantly enhanced after the transfection. CONCLUSION: The PAK1 gene transfection can increase the expression of PAK1 in SW480 cells and enhance the invasiveness of the cells. PAK1 can be associated with the invasiveness and metastasis of colorectal carcinoma cells.

[PI3K p85alpha expression and its role in the progression of colorectal cancer].

OBJECTIVE: To investigate the expression of PI3K p85alpha in normal colorectal tissue, colorectal adenoma and primary colorectal carcinoma and explore its significance in the progression of colorectal cancer. METHODS: The expression of PI3K p85alpha was detected in 116 normal colorectal tissue, colorectal adenoma and primary colorectal carcinoma specimens using immunohistochemical staining, and the relationship between the expression of PI3K p85alpha protein and the clinicopathological factors was analyzed. RESULTS: The positivity rates of the expression of PI3K p85alpha protein increased gradually in the progression of colorectal cancer and showed significant differences between the tissues (P<0.05). A significant difference was also noted in the positivity rates of the PI3K p85alpha expression in colorectal carcinoma tissues at different Dukes' stages (P<0.05). No obvious correlation was found between PI3K p85alpha expression and the degree of the tumor differentiation. CONCLUSIONS: Abnormal PI3K p85alpha expression occurs in the progression of colorectal cancer in close relation to the clinical stage, and the PI3K/AKT pathway plays an important role in the progression of colorectal cancer.

[Syndecan-1 expression and its significance in colitis].

OBJECTIVE: To explore the effect of syndecan-1 (Sdc-1) in the pathogenesis of colitis. METHODS: Thirty BALB/c mice were forced to drink 4% dextran sodium sulphate (DSS) in distilled water as the sole source of drinking fluid for 7 days, distilled water for 10 days, and 4% DSS in distilled water for another 7 days so as to establish colitis models and then were randomly divided into 3 equal groups: model groups 1, 2, and 3 to be killed 8, 18, and 25 days after the DSS drinking respectively to take their colons. Another 10 mice were fed with distilled water as control group and were killed on Day 8. Microscopy was used to evaluate the histological score of the colon. RT-PCR was used to detect the expression of Sdc-1 mRNA and IL-1 mRNA in the colon mucosa. Immunohistochemistry was conducted to detect the Sdc-1 protein level. RESULTS: The histological scores of the 3 model groups were all significantly higher than that of the control group (F = 448.717, P < 0.01) and the score was the highest in the model group 1 and then gradually decreased. There was not significant differences in the Sdc-1 mRNA expression among different groups (F = 0.822, P > 0.05). The levels of Sdc-1 protein of the 3 model groups were all significantly lower than that of the control group (F = 865.586, P < 0.01), and the Sdc-1 protein level was the lowest level in the model group1, and then increased gradually. The expression of IL-1 mRNA of the 3 model groups were all significantly higher than that of the control group (F = 103.833, P < 0.01), and the IL-1 mRNA level was the highest in the model group1 and then decreased gradually. CONCLUSION: The severity of colitis is associated with the reduction of Sdc-1 protein level, but not with the Sdc-1 mRNA level in the colon mucosa. The reduction of Sdc-1 protein level may be associated to increase of IL-1 level.

[Short hairpin RNA-mediated survivin gene silencing inhibits invasion and metastasis of human colon carcinoma cell line SW480 in vitro].

OBJECTIVE: To investigate the effect of short hairpin RNA (shRNA) targeting survivin on adhesion and invasion of human colon carcinoma cell line SW480 in vitro. METHODS: According to the sequence of the coding region of survivin gene, two strings of 19 nucleotides of inverted sequence flanking the loop sequence of two complementary 9-base oligonucleotides were designed and synthesized to prepare the hairpin construct as the DNA templates for the target shRNA. The shRNA templates were cloned into shRNA expression vector pRNAT-U6.1/Neo, and the resulted vector pRNAT-U6.1/Neo-survivin was transfected into SW480 cells using Lipofectamine 2000. Western blotting was performed to evaluate survivin gene silencing induced by shRNA transfection at the protein level, and the biological behaviors of the SW480 cells were investigated by cell-matrix adhesion, invasion and gelatin-zymography assays. RESULTS: Western blotting revealed significantly lowered survivin protein expression in transfected SW480 cells, and survivin gene silencing induced by shRNA significantly suppressed the metastatic potential of SW480 cells in association with suppressed MMPs activity. CONCLUSIONS: Survivin may play an important role in modulating human colorectal carcinoma cell invasion and metastasis, and survivin gene silencing can inhibit human colorectal cancer cell invasion and the production of MMP-2 and MMP-9. Survivin may affect invasion and metastasis of human colorectal carcinoma cells via regulating the production of MMPs.

[Selective COX-2 inhibitor delays experimental gastric ulcer healing by stimulating gastric acid secretion in rats].

OBJECTIVE: To observe the effect of selective cyclooxygenase-2 (COX-2) inhibitor on the healing of experimental gastric ulcer in rats and explore its mechanisms in light of gastric acid secretion. METHODS: Gastric ulcers were induced in rats by an application of acetic acid to the serosal surface of the anterior gastric body. The effects of selective COX-2 inhibitor, celecoxib, on the healing of gastric ulcer, the total acidity of gastric juice, the expressions of H+, K+-ATPase mRNA and protein, and the ultrastructure of the parietal cell were observed in comparison with the effects of normal saline. RESULTS: Nine days after ulcer induction, the ulcer area was 11.9-/+3.1 mm square and 19.7-/+3.8 mm square in rats with normal saline and celecoxib treatments, respectively (P<0.01). The total acidity of gastric juice and the expressions of H+, K+-ATPase mRNA and protein in celecoxib group were significantly higher than that in normal saline group at both 6 and 9 days after ulcer induction, but no significant difference was found between the two groups in the amount of secretary canaliculus and microvillus. CONCLUSION: Selective COX-2 inhibitor can significantly delay the healing of experimental gastric ulcer in rats, the mechanism of which might be associated with enhanced digestive action of gastric acid on the new granulation tissue at the ulcer base as a result of celecoxib-stimulated gastric acid secretion of the parietal cells.

[Protective effect of epigallocatechin-3-gallate on inflammatory bowel disease: experiment with rat models of induced colitis].

OBJECTIVE: To explore the protective effect of epigallocatechin-3-gallate (EGCG) on ulcerative colitis (UC) and mechanism thereof. METHODS: Sixty SD rats underwent enema of trinitrobenzene sulfonic acid (TNBS) to cause UC and then randomly divided into 6 groups: model group, undergoing enema of normal saline (NS) once a day for 2 weeks; positive drug control group, undergoing enema of 5-aminosalicylic acid (ASA), an anti-UC drug; high-dose EGCG group, undergoing enema of 100 mg/kg EGCG; low-dose EGCG group, undergoing 5 enema of 50 mg/kg EGCG; and EGCG pretreatment group, undergoing enema of 100 mg/kg once a day 3 days before the model establishment and then once a day for 2 weeks after the model establishment. Another 12 rats were used as normal controls. Two weeks later the rats were killed. The histological score of the colonic mucosa was evaluated. The cyclooxygenase-2 protein expression in the colonic mucosa was detected by immunohistochemistry and the cyclooxygenase-2 mRNA expression was assessed by semiquantitative reverse-transcription polymerase chain reaction. RESULTS: The histological score of the model group was 6.4 +/- 2.7, significantly higher than that of the normal control group (1.0 +/- 0.7, P < 0.01). The histological scores of the 5-ASA, and 100 mg/kg and 50 mg/kg EGCG groups were 3.4 +/- 1.8, 2.6 +/- 1.5, and 4.0 +/- 2.0 respectively, all significantly lower than that of the model group (all P < 0.05). The histological scores of the EGCG pretreatment group was the lowest (1.2 +/- 0.8), especially compared with the model group (P < 0.01). Cyclooxygenase -2 mRNA was not expressed in the normal control group, was highly expressed in the model group, and the expression levels of the 5-ASA and EGCG groups were all significantly lower than that of the model group (chi(2) = 22.017, P < 0.05). CONCLUSION: Preventing and ameliorating colitis by inhibiting cyclooxygenase-2 activity, EGCG may be a potential medicine in treating inflammatory bowel disease.

[Clinical classification of Peutz-Jeghers syndrome].

OBJECTIVE: To propose the clinical classification of Peutz-Jeghers syndrome (PJS). METHODS AND RESULTS: Retrospective analysis of 52 patients with PJS admitted in Nanfang Hospital from 1980 to 2003 was conducted. Twenty-four patients were found to have family history of PJS, who had a mean age of 19 years. In the PJS patients, the incidence of gastric polyps was 64.4%, colorectal polyps 76%, and small bowel polyps 95%. The number of polyps was above 50 in 19 of the 31 patients with gastric polyps, in 18 of the 38 patients with colorectal polyps, and in 8 of the 19 patients with small bowel polyps. The pathology of the majority of the polyps (63/108) was characterized by hamartomas, and the incidence of malignancy was 13.5% in the PJS patients. CONCLUSIONS: PJS can be classified according to family history and location, pathology, and number of the polyps. As most patients with over 50 polyps require surgical intervention, 50 polyps is recommended as the criteria for PJS classification. Endoscopic surgery may suffice for management of patients with fewer polyps (<50), while in patients with more polyps or small bowel polyps, open surgery combined with intraoperative endoscopic surgery is recommended.

[Changes in cyclooxygenase gene expression during spontaneous recovery from stress ulcer in rats].

OBJECTIVE: To observe the changes in gene expression of cyclooxygenase (COX) during spontaneous recovery from stress ulcer in rats exposed to water immersion and restraint stress (WRS). METHODS: A rat model of stress ulcer was established by means of WRS, in which the changes in COX expression were detected with immunohistochemistry and reverse transcription (RT)-PCR. RESULTS: Very low levels of COX-2 expression were detected in the gastric mucosa of the control rats, and the expression increased significantly during the healing process of the stress ulcer (P<0.05). COX-1 expression in the gastric mucosa showed no significant difference between the control group and the stress ulcer groups during healing (P>0.05). CONCLUSION: COX-1 and COX-2 expressions in rat gastric mucosa during the recovery from stress ulcer participate in the recovery of the damaged mucosa possibly by mediating prostaglandin secretion.

Gastrointestinal hormone abnormalities and G and D cells in functional dyspepsia patients with gastric dysmotility.

AIM: To investigate the relationship between gastric dysmotility, gastrointestinal hormone abnormalities, and neuroendocrine cells in gastrointestinal mucosa in patients with functional dyspepsia (FD). METHODS: Gastric emptying was assessed with solid radiopaque markers in 54 FD patients, and the patients were divided into two groups according to the results, one with delayed gastric emptying and the other with normal gastric emptying. Seventeen healthy volunteers acted as normal controls. Fasting and postprandial plasma levels and gastroduodenal mucosal levels of gastrointestinal hormones gastrin, somatostatin (SS) and neurotensin (NT) were measured by radioimmunoassay in all the subjects. G cells (gastrin-producing cells) and D cells (SS-producing cells) in gastric antral mucosa were immunostained with rabbit anti-gastrin polyclonal antibody and rabbit anti-SS polyclonal antibody, respectively, and analyzed quantitatively by computerized image analysis. RESULTS: The postprandial plasma gastrin levels, the fasting and postprandial plasma levels and the gastric and duodenal mucosal levels of NT were significantly higher in the FD patients with delayed gastric emptying than in those with normal gastric emptying and normal controls. The number and gray value of G and D cells and the G cell/D cell number ratio did not differ significantly between normal controls and the FD patients with or without delayed gastric emptying. CONCLUSION: Our findings suggest that the abnormalities of gastrin and NT may play a role in the pathophysiology of gastric dysmotility in FD patients, and the abnormality of postprandial plasma gastrin levels in FD patients with delayed gastric emptying is not related to the changes both in the number and gray value of G cells and in the G cell/D cell number ratio in gastric antral mucosa.

Effect of environmental hyperthermia on gastrin, somatostatin and motilin in rat ulcerated antral mucosa.

AIM: To study the effect of environmental hyperthermia on gastrin, somatostatin and motilin in rat ulcerated antral mucosa. METHODS: Forty-two Wistar rats were equally divided into six groups, according to the room temperature (high and normal) and the treatment (acetic acid, normal saline and no treatment). Levels of gastrin, somatostatin and motilin in rat ulcerated antral mucosa were measured with a radioimmunoassay method. RESULTS: The average temperature and humidity were 32.5 degrees and 66.7% for the high temperature group, and 21.1 degrees and 49.3% for the normal temperature group, respectively. Gastric ulcer model was successfully induced in rat injected with 0.05 mL acetic acid into the antrum. In rats with gastric ulcers, the levels of gastrin and motilin increased, whereas the somatostatin level declined in antral mucosa, compared with those in rats treated with normal saline and the controls. However, the change extent in the levels of gastrin, motilin and somatostatin in antral mucosa was less in the high temperature group than in the normal temperature group. CONCLUSION: The levels of gastrin, somatostatin and motilin in rat ulcerated antral mucosal tissue remain relatively stable in a high temperature environment, which may relate to the equilibration of the dynamic system.

[Expressions of early growth response 1 and tissue factor in caerulein-induced acute pancreatitis tissues in rats].

OBJECTIVE: To observe the expressions of early growth response 1 (Egr-1) and tissue factor (TF) in rat tissues of acute pancreatitis induced by caerulein and to explore their significance. METHODS: Pancreatitis was induced in rats by high-dose intraabdominal caerulein injection. The changes of Egr-1 mRNA and protein in pancreas were measured by quantitative PCR and Western blotting, and the localization of Egr-1 protein in acinar cells was visualized by immunohistochemistry. TF mRNA levels were also measured by quantitative PCR. High-dose bombesin-stimulated rats served as the negative control. RESULTS: Egr-1 mRNA was rapidly increased in the pancreas of rats stimulated by high-dose cearulein, and reached the peak level 30 min after the stimulation, whereas band for peak Egr-1 protein level was visualized by Western blotting till 2 h after stimulation. Immunohistochemistry showed that almost every acinar cell in the pancreas was Egr-1-positive, especially in the nucleus. In line with Egr-1 activation, TF mRNA was detected 1 h after the stimulation and increased steadily within the initial 4 h. Only a small quantity of Egr-1 mRNA expression was observed in bombesin-stimulated rats, in which no Egr-1 protein or TF mRNA were detected. CONCLUSION: Egr-1 mRNA and protein were up-regulated in the early stage of pancreatitis. Egr-1, as a pro-inflammatory transcriptional factor, probably plays an important role in the initiation of acute pancreatitis, and its action might be partially mediated through the up-regulation of TF expression.

Detection of point mutation in K-ras oncogene at codon 12 in pancreatic diseases.

AIM: To investigate frequency and clinical significance of K-ras mutations in pancreatic diseases and to identify its diagnostic values in pancreatic carcinoma. METHODS: 117 ductal lesions were identified in the available sections from pancreatic resection specimens of pancreatic ductal adenocarcinoma, comprising 24 pancreatic ductal adenocarcinoma, 19 peritumoral ductal atypical hyperplasia, 58 peritumoral ductal hyperplasia and 19 normal duct at the tumor free resection margin. 24 ductal lesions were got from 24 chronic pancreatitis. DNA was extracted. Codon 12 K-ras mutations were examined using the two-step polymerase chain reaction (PCR) combined with restriction enzyme digestion, followed by nonradioisotopic single-strand conformation polymorphism (SSCP) analysis and by means of automated DNA sequencing. RESULTS: K-ras mutation rate of the pancreatic carcinoma was 79%(19/24) which was significantly higher than that in the chronic pancreatitis 33%(8/24) (P<0.01). It was also found that K-ras mutation rate was progressively increased from normal duct at the tumor free resection margin, peritumoral ductal hyperplasia, peritumoral ductal atypical hyperplasia to pancreatic ductal adenocarcinoma. The mutation pattern of K-ras 12 codon of chronic pancreatitis was GGT-GAT, GGT and CGT, which is identical to that in pancreatic carcinoma. CONCLUSION: K-ras mutation may play a role in the malignant transformation of pancreatic ductal cell. K-ras mutation was not specific enough to diagnose pancreatic carcinoma.

G and D cells in rat antral mucosa: an immunoelectron microscopic study.

AIM: To investigate the gastrin secreting cells (G cells) and the somatostatin secreting cells (D cells) of antral mucosa in rats at the ultrastructural level. METHODS: Revised immunoelectron microscopic technique was used to detect the G cells and D cells in rat antral mucosa through gastrin and somatostatin antibodies labeled by colloidal gold. Also the relevant quantitative analysis regarding the granular number of colloidal gold in G cells and in D cells was conducted. RESULTS: Immunological granules of colloidal gold were distributed in G cells and D cells. Gastrin labeled golden granules or somatostatin labeled ones presented mainly as lobation-like or island-like congeries. Most of the golden congeries were observed dissociated in cytoplasms of G cells or D cells, near the basement membrane. A few golden congeries were located in nuclei. The number of golden granules in one G cell was around 107.04 +/- 19.68 and was 83.36 +/- 17.58 in one D cell. CONCLUSION: Gastrin secreting granules are located in cytoplasms and nuclei of G cells, and somatostatin secreting granules both in cytoplasms and in nuclei of D cells. The number of golden granules can be quantitatively analyzed to determine the relative amount of gastrin secreting granules or somatostatin secreting granules.

Overexpression of c-fos in Helicobacter pylori-induced gastric precancerosis of Mongolian gerbil.

AIM: To explore dysregulation of c-fos in several human malignancies, and to further investigate the role of c-fos in Helicobacter pylori (H. pylori)-induced gastric precancerosis. METHODS: Four-week-old male Mongolian gerbils were employed in the study. 0.5 mL 1X10(8) cfu/L suspension of H. pylori NCTC 11 637 in Brucella broth were inoculated orally into 20 Mongolian gerbils. Another 20 gerbils were inoculated with Brucella broth as controls. 10 of the infected gerbils and 10 of the non- infected control gerbils were sacrificed at 25 and 45 weeks after infection. The stomach of each gerbil was removed and opened for macroscopic observation. The expression of c-fos was analyzed by RT-PCR and immunohistochemical studies in H. pylori-induced gastric precancerosis of Mongolian gerbil. Half of each gastric antrum mucosa was dissected for RNA isolation and RT-PCR. beta-actin was used as the housekeeping gene and amplified with c-fos as contrast. PCR products of c-fos were analyzed by gel image system and the level of c-fos was reflected with the ratio of c-fos/beta-actin. The immunostaining for c-fos was conducted using monoclonal antibody of c-fos and the StreptAvidin-Biotin-enzyme Complex kit. RESULTS: H. pylori was constantly found in all infected animals in this study. After infection of H. pylori for 25 weeks, ulcers were observed in the antral and the body of stomach of 60 % infected animals (6/10). Histological examination showed that all animals developed severe inflammation, especially in the area close to ulcers, and multifocal lymphoid follicles appeared in the lamina propria and submucosa. After infection of H. pylori for 45 weeks, severe atrophic gastritis in all infected animals, intestinal metaplasia in 80 % infected animals (8/10) and dysplasia in 60 % infected animals (6/10) could be observed. C-fos mRNA levels were significantly higher after infection of H. pylori for 25 weeks (1.84+/-0.79), and for 45 weeks (1.59+/-0.37) than those in control-animals (0.74+/-0.22, P<0.01). C-fos mRNA levels were increased 2.5-fold by 25th week (P<0.01) and 2.1-fold by 45th week (P<0.01) in precancerosis induced by H. pylori, when compared with normal gastric epithelium of Mongolian gerbil. Immunohistochemical staining revealed exclusive nuclear staining of c-fos. Furthermore, there was a sequential increase in c-fos positive cells from normal epithelium to precancerosis. CONCLUSION: The study suggested that overexpression of c-fos occurs relatively early in gastric tumorigenesis in this precancerosis model induced by H. pylori.

Effect of high temperature on gastrin, somatostatin and motilin production in ulcerous gastric antral mucosa of rats.

OBJECTIVE: To investigate the changes of gastrin, somatostatin and motilin production in the gastric antral mucosa of rats with experimental gastric ulcer. METHODS: Rat models of gastric ulcer model were induced successfully by injection of acetic acid into the gastric antral wall of 2 groups of Wistar rats (7 in each group) that were subjected to environment of either high or normal temperature. Another 2 groups of rats (n=7) receiving normal saline injection in the same manner, along with still another 2 groups (n=7) without any treatment, all of which were kept under conditions with different temperatures accordingly, constituted the control groups. The levels of gastrin, somatostatin and motilin in the gastric antral mucosa of the rats were measured with radioimmunoassay. RESULTS: In rats with gastric ulcer, the levels of gastrin and motilin in the antral mucosa increased, but in a lesser scale in rats with ulcer kept in high temperature than in normal temperature group, while that of somatostatin was reduced. The level of somatostatin declined less in the high temperature group with ulcer than in the normal temperature group with ulcer. CONCLUSION: High temperature can affect gastrin, somatostatin and motilin production in the gastric antral mucosa of rats with gastric ulcer.

[Effect of Helicobacter pylori infection on gastric mucosal cell proliferation in Mongolian gerbils].

OBJECTIVE: To explore the mechanism that Helicobacter pylori (H. pylori) infection can induce adenocarcinoma in Mongolian gerbil model with long-term H. pylori infection. METHODS: Mongolian gerbil model with long-term H. pylori infection was established by inoculation H. pylori NCTC 11637 strain, and immunohistochemical straining and in situ hybridization were employed to observe changes in gastric mucosal cell proliferation due to H. pylori infection. RESULTS: Mongolian gerbil model with long-term H. pylori infection was successfully established. Immunohistochemical staining of 5'-bromodeoxyuridine (BrdU) and proliferating cell nuclei antigen (PCNA) showed that H. pylori infection induced the increase in gastric mucosal cell proliferation (P<0.05), and in situ hybridization of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) revealed elevated expressions of EGF mRNA and EGFR mRNA with time passage after H. pylori infection (P<0.05). CONCLUSION: H. pylori inoculation can induce abnormality in gastric mucosal cell proliferation, which is instrumental for the progression from chronic gastritis to glandular atrophy, intestinal metaplasis and ultimately to atypical hyperplasia. The abnormal expressions of EGF and EGFR may be the key element for abnormality of gastric mucosal cell proliferation.

[Electron microscopic observation of endocrine cells in the antrum in response to Helicobacter pylori infection].

OBJECTIVE: To observe the ultrastructural changes of the endocrine cells in the antrum after the onset of Helicobacter pylori (Hp) infection. METHODS: Seven patients with chronic gastritis were included in this study, and toluidine blue staining and rapid urease test were performed to determine the Hp status of the gastric antral mucosa biopsies. Five patients identified as being positive for Hp constituted the test group, leaving the 2 Hp-negative patients serving as control. The endocrine cells in the antrum of the patients were sampled to observe the ultrastructural changes by transmission electron microscopy (TEM). RESULTS: TEM showed increased electron density of the secretion granules in the endocrine cells, and secretions in the parietal cells were active. CONCLUSION: The ultrastructural changes of the endocrine cells in the antrum might explain high gastrin levels after the onset of Hp infection.

Gastrin, somatostatin, G and D cells of gastric ulcer in rats.

AIM: To investigate the relationship among gastrin, somatostatin, G and D cells in gastric ulcer and in its healing process in rats. METHODS: Fourty-nine Wistar rats were divided into 7 groups. The gastric ulcer model was induced by acetic acid successfully. The gastrin and the somatostatin in rat plasma, gastric fluid and antral tissue were measured by radioimmunoassay(RIA). G and D cells in antral mucosa were analyzed with polyclonal antibody of gastrin and somatostatin by immunohistochemical method and Quantimet 500 image analysis system. RESULTS: In gastric ulcer, the level of gastrin in plasma, gastric fluid, and antral tissue increased, that of somatostatin declined, and the disorder gradually recovered to the normal level in the healing process. Immunohistochemical technique of G and D cells in antral mucosa demonstrated that the number of G cells increased and that of D cells decreased, both areas of G and D cells declined, the ratio of number and area of G/D increased in gastric ulcer, and the disorder gradually recovered in the healing process. CONCLUSION: In gastric ulcer, the increased gastrin secreted by G cells, the declined somatostatin secreted by D cells, and the disordered G/D cell ratio can lead to gastrointestinal dysfunction.