Effect of long-term prostacyclin treatment on the gastric mucosa of rat

According to Bálint and Varró, oral administration of prostacyclin (PGI2) resulted in a significant increase of the DNA-content of the gastric mucosa within a short period of time. In the present study, there was no change in the protein content of the gastric mucosa after oral administration of 100 micrograms/kg/day of PGI2 for 80 days, while the DNA-content increased significantly. The RNA/DNA ratio decreased. Histologically a significant increase in the thickness of the gastric mucosa, as well as in the number of parietal and epithelial cells were found. The cell hyperplasia in the corpus mucosa was accompanied by a decreased number of G-cells of the antral mucosa. The increase of parietal cell number and the decrease of G-cell number after long term PGI2 administration might be explained by the divergent effect of treatment on the kinetics of the different cell types in the gastric mucosa.     

血清胃蛋白酶原联合G-17对萎缩性胃炎及胃癌早期诊断价值

目的:探索检测血清胃蛋白酶原Ⅰ(PGⅠ)、胃蛋白酶原Ⅱ(PGⅡ)、胃泌素-17(G-17)在萎缩性胃炎及胃癌中的诊断价值。方法:收集医院2015年2月至12月门诊及住院的慢性非萎缩性胃炎44例(非萎缩性胃炎组),慢性萎缩性胃炎47例(萎缩性胃炎组),早期胃癌42例(胃癌组)。采用酶联免疫吸附试验(ELISA)测定各组血清PGⅠ、PGⅡ、G-17的水平,同时计算PGⅠ/PGⅡ的比值(PGR),比较各组指标间的差异,同时绘制各指标筛查萎缩性胃炎及胃癌的受试者工作曲线(ROC)曲线,分别评价其诊断价值。结果:胃癌组及萎缩性胃炎组的血清PGⅠ、PGR水平较非萎缩性胃炎组明显下降,且胃癌组下降更明显,差异均具有统计学意义(P0.05),萎缩性胃炎组血清PGⅡ显著低于非萎缩性胃炎组,差异均具有统计学意义(P0.05);胃癌组的血清G-17水平较非萎缩性胃炎组及萎缩性胃炎组均升高,差异有统计学意义(P0.05)。血清PGⅠ筛查萎缩性胃炎的最佳界值为PGⅠ90 ng/m L,其灵敏度和特异度分别为71.5%和51.0%,血清PGR筛查萎缩性胃炎的最佳界值为PGR8,其灵敏度和特异度分别为71.9%和54.0%,血清G-17筛查萎缩性胃炎的最佳界值为G-175 pmol/L,其灵敏度和特异度分别为66.1%和64.0%。血清PGⅠ筛查胃癌的最佳界值为PGⅠ73 ng/m L,其灵敏度和特异度分别为86.0%和74.9%;血清PGR筛查胃癌的最佳界值为PGR3,其灵敏度和特异度分别为90.2%和62.5%;血清G-17筛查胃癌的最佳界值为G-174 pmol/L,其灵敏度和特异度分别为62.5%和61.3%。结论:胃癌及萎缩性胃炎患者血清PGⅠ、PGR水平下降明显,且胃癌患者的血清G-17异常升高,血清PG联合GS-17测定可用于萎缩性胃炎及胃癌的早期筛查。     

Gastric prostacyclin (PGI2) prevents stress-induced gastric mucosal injury in rats primarily by inhibiting leukocyte activation.

We investigated whether, in rats, gastric prostacyclin (PGI2) prevented gastric mucosal injury that was induced by water-immersion restraint stress by inhibiting leukocyte activation. Gastric levels of 6-keto-PGF1alpha, a stable metabolite of PGI2, increased transiently 30 min after stress, followed by a decrease to below the baseline 6-8 h after stress. Gastric mucosal blood flow decreased to approximately 40% of the baseline level 8 h after stress. Myeloperoxidase activity was significantly increased 8 h after stress. Treatment with indomethacin before stress inhibited the increase in 6-keto-PGF1alpha levels and markedly reduced mucosal blood flow. It also markedly increased leukocyte accumulation and mucosal lesion formation. Iloprost, a stable PGI2 analog, inhibited the indomethacin-induced decrease in mucosal blood flow, mucosal lesion exacerbation, and increase in leukocyte accumulation. Nitrogen mustard-induced leukocytopenia inhibited the indomethacin-associated lesion exacerbation and the increase in leukocyte accumulation, but not the decreases in mucosal blood flow. These observations indicate that gastric PGI2 decreases gastric mucosal lesion formation primarily by inhibiting leukocyte accumulation.     

内镜下黏膜切除术治疗胃息肉的疗效及对血清ProGRP、PGI水平的影响

摘要 目的：探讨内镜下黏膜切除术治疗胃息肉的疗效及对血清胃泌素释放肽前体（ProGRP）、胃蛋白酶原I（PGI）水平的影响。方法：选取我院2019年8月到2022年8月收治的120例胃息肉患者作为研究对象，依照手术方式的不同进行分组，其中将选择常规内镜下电凝切除术治疗的60例患者分为对照组，选择内镜下黏膜切除术治疗的60例患者分为观察组。对比两组患者不良反应发生情况与治疗费用，手术前与手术后血清ProGRP、PGI表达水平以及炎症因子表达水平，对比两组患者整体切除率和并发症发生情况。结果：两组患者总治疗费用对比无差异（P＞0.05），观察组患者术后不良反应发生率较对照组低（P＜0.05）；两组患者手术前血清ProGRP、PGI水平对比无差异（P＞0.05），治疗后两组患者均降低，且观察组较对照组低（P＜0.05）；两组患者手术前PCT、CRP、IL-6、IL-2对比无明显差异（P＞0.05），手术后两组患者PCT、CRP、IL-6、IL-2均升高，且观察组低于对照组（P＜0.05）；两组患者胃息肉均被完整切除，整体切除率对比无差异；且观察组穿孔、迟发性出血以及感染等并发症发生率虽低于对照组，但比较无差异（P＞0.05）。结论：对胃息肉患者采取内镜下黏膜切除术与常规内镜下电凝切除术均能够完整的切除胃息肉，且治疗费用相当。而应用内镜下黏膜切除术能够降低患者ProGRP、PGI水平，降低机体炎症因子反应，且并发症发生率较低，值得临床应用推广。     

Polarized distribution of actin isoforms in gastric parietal cells.

The actin genes encode several structurally similar, but perhaps functionally different, protein isoforms that mediate contractile function in muscle cells and determine the morphology and motility in nonmuscle cells. To reveal the isoform profile in the gastric monomeric actin pool, we purified actin from the cytosol of gastric epithelial cells by DNase I affinity chromatography followed by two-dimensional gel electrophoresis. Actin isoforms were identified by Western blotting with a monoclonal antibody against all actin isoforms and two isoform-specific antibodies against cytoplasmic beta-actin and gamma-actin. Densitometry revealed a ratio for beta-actin/gamma-actin that equaled 0.73 +/- 0.09 in the cytosol. To assess the distribution of actin isoforms in gastric glandular cells in relation to ezrin, a putative membrane-cytoskeleton linker, we carried out double immunofluorescence using actin-isoform-specific antibodies and ezrin antibody. Immunostaining confirmed that ezrin resides mainly in canaliculi and apical plasma membrane of parietal cells. Staining for the beta-actin isoform was intense along the entire gland lumen and within the canaliculi of parietal cells, thus predominantly near the apical membrane of all gastric epithelial cells, although lower levels of beta-actin were also identified near the basolateral membrane. The gamma-actin isoform was distributed heavily near the basolateral membrane of parietal cells, with much less intense staining of parietal cell canaliculi and no staining of apical membranes. Within parietal cells, the cellular localization of beta-actin, but not gamma-actin, isoform superimposed onto that of ezrin. In a search for a possible selective interaction between actin isoforms and ezrin, we carried out immunoprecipitation experiments on gastric membrane extracts in which substantial amounts of actin were co-eluted with ezrin from an anti-ezrin affinity column. The ratio of beta-actin/gamma-actin in the immunoprecipitate (beta/gamma = 2.14 +/- 0.32) was significantly greater than that found in the cytosolic fraction. In summary, we have shown that beta- and gamma-actin isoforms are differentially distributed in gastric parietal cells. Furthermore, our data suggest a preferential, but not exclusive, interaction between beta-actin and ezrin in gastric parietal cells. Finally, our results suggest that the beta- and gamma-actin-based cytoskeleton networks might function separately in response to the stimulation of acid secretion.     

The role of serum pepsinogen and gastrin test for the detection of gastric cancer in Korea

Background and Aim: This study was performed to determine whether serum pepsinogen (PG) and gastrin testing can be used to detect gastric cancer in Korea. Methods: Serum levels of PG I (sPGI) and sPGII, PG I/II ratios, and gastrin levels were measured in 1006 patients with gastroduodenal diseases including cancer. Follow‐up tests were performed 1 year after Helicobacter pylori eradication. Results: sPGI and sPGII levels increased and PG I/II ratios decreased in line with the severity of activity, chronic inflammation, and the presence of H. pylori (p < .01). In contrast, sPGI levels and PG I/II ratios decreased in proportion with the severity of atrophic gastritis (AG)/intestinal metaplasia (p < .01). Gastrin levels were found to be correlated with chronic inflammation negatively in the antrum but positively in the corpus. H. pylori eradication reduced sPGI, sPGII, and gastrin levels, and increased PG I/II ratios to the levels of H. pylori‐negative patients, and was found to be correlated with reductions in activity and chronic inflammation of gastritis. The sensitivity and specificity of a PG I/II ratio of ≤ 3.0 for the detection of dysplasia or cancer were 55.8–62.3% and 61%, respectively. In addition, sPGI and sPGII levels of intestinal‐type cancer were significantly lower than those of the diffuse type, respectively (p = .008 and p = .05, respectively). Gastric cancer risk was highest in the H. pylori‐positive, low PGI/II ratio (≤ 3.0) group with an odds ratio of 5.52 (confidence interval: 2.83–10.77). Conclusion: PG I/II ratio (≤ 3.0) was found to be a reliable marker for the detection of dysplasia or gastric cancer, especially of the intestinal type. This detection power of PG I/II ratio (≤ 3.0) significantly increased in the presence of H. pylori, and thus, provides a means of selecting those at high risk of developing gastric cancer in Korea.     

Stimulation of inositol phosphate and diacylglycerol production by RHC 80267, a diacylglycerol-lipase inhibitor, in rat gastric parietal cells: effects on hydrogen ion secretion

RHC 80267, on inhibitor of diacylglycerol lipase, was used to investigate the role of diacylglycerol in acid secretion by isolated rat gastric parietal cells. Unexpectedly, RHC 80267 stimulated the production of inositol phosphates in [3H]inositol-prelabeled cells and increased levels of 32P-labeled phosphatidic acid to the same degree as did carbachol. RHC 80267 increased diacylglycerol to a greater extent than did carbachol, and additionally decreased levels of [3H]arachidonic acid. This suggests that RHC 80267 stimulated phospholipase C and inhibited diacylglycerol lipase in parietal cells. RHC inhibited [14C]aminopyrine uptake, a measure of acid secretion, stimulated by carbachol or by simultaneous addition of carbachol and dibutyryl-cAMP. These data support the model that the diacylglycerol/protein kinase C branch of the phosphoinositide system is inhibitory to acid secretion.     

Modulatory role of phosphoinositide 3-kinase in gastric acid secretion

The gastric parietal cell is responsible for the secretion of HCl into the lumen of the stomach mainly due to stimulation by histamine via the cAMP pathway. However, the participation of several other receptors and pathways have been discovered to influence both stimulation and inhibition of acid secretion (e.g., cholinergic). Here we examine the role of phosphoinositide 3-kinase (PI3K) in the modulation of acid secretion. Treatment of isolated gastric glands and parietal cells with the PI3K inhibitor, LY294002 (LY), potentiated acid secretion in response to histamine to nearly the maximal secretion obtained with histamine plus phosphodiesterase inhibitors. As cAMP levels were elevated in response to histamine plus LY, but other means of elevating cAMP (e.g., forskolin, dbcAMP) were not influenced by LY, we posited that the effect might require activation of G-protein-coupled histamine H(2) receptors, possibly through the protein kinase B pathway (also known as Akt). Study of downstream effectors of PI3K showed that histaminergic stimulation increased Akt phosphorylation, which in turn was blocked by inhibition of PI3K. Expression studies showed that high expression of active Akt decreased acid secretion, whereas dominant-negative Akt increased acid secretion. Taken together, these data suggest stimulation with histamine increases the activity of PI3K leading to increased activity of Akt and decreased levels of cAMP in the parietal cell.     

应激状态下NO的胃粘膜保护作用及其与壁细胞泌酸的关系

目的:探讨应激状态下一氧化氮(NO)的胃粘膜保护作用及其与壁细胞泌酸的关系.方法:采用水浸-束缚应激(WRS)方法制备应激性溃疡(SU)动物模型,检测胃粘膜溃疡指数(UI)、胃粘膜NO含量和壁细胞H ,K -ATPase活性,观察L-硝基精氨酸甲酯(L-NAME)和L-精氨酸(L-Arg)对应激后大鼠壁细胞H ,K -ATPase活性及胃粘膜损伤的影响.结果:L-NAME(20 mg·kg-1)可使胃粘膜NO含量减少(P＜0.01),壁细胞H ,K -AT-Pase活性增加(P＜0.05),并加重应激所致的胃粘膜损伤;L-Arg(300 mg·kg-1)则使胃粘膜NO含量增加(P＜0.01),壁细胞H ,K -ATPase活性下降(P＜0.05),减轻应激所致胃粘膜损伤.结论:NO对应激状态下大鼠胃粘膜具有保护作用,其机制与抑制壁细胞H ,K -ATPase活性有关.     

VIP inhibits histamine-induced ultrastructural changes related to acid secretion by parietal cells

We have studied the in vitro effect of VIP and histamine on ultrastructure of the parietal cells in isolated guinea pig fundic glands. The morphological changes induced by histamine in the parietal cells can be compared to those observed after histamine stimulation in vivo or in vitro on gastric mucosa preparations. In contrast, VIP incubation did not produce the ultrastructural changes related to gastric acid secretion, in resting parietal cells. Pretreatment of the glands by VIP resulted in a remarkable suppression of the histamine effect, since the parietal cells assumed an almost resting state. The data (1) indicate that the parietal cells in isolated gastric glands of the guinea pig retain in vitro the capacity to undergo the ultrastructural changes that are related to acid secretion in vivo after histamine or cAMP and (2) suggest that VIP is an inhibitor of histamine-induced gastric acid secretion in the guinea pig. It is proposed that VIP could act directly on the parietal cell via cAMP-phosphodiesterase activation, or indirectly via gastric somatostatin and/or prostaglandin secretions, inhibiting the H2 receptor-cAMP system of the parietal cell.     

Alteration of endothelin-1 concentration in STZ-induced diabetic rat nephropathy. Effects of a PGI(2) derivative

BACKGROUND: Recently, an endothelin (ET-1) with a potent vasoconstrictive activity and stimulative activity of vascular muscular cell growth was discovered and blood ET-1 levels were higher in diabetic patients than in healthy subjects, suggesting that high ET-1 levels assist development and progression of diabetic microangiography. METHODS: We examined renal function, and serum and tissue ET-1 levels in streptozotocin (STZ)-induced diabetic rats treated with a prostaglandin (PG) I(2) derivative to investigate the effect of PGI(2) in diabetic vascular disturbance. RESULTS: Renal weight, urinary albumin, urinary N-acetyl-beta,D-glucosaminidase (NAG) and serum ET-1 levels increased in STZ-induced diabetic rats, and a tendency to increase in renal tissue ET-1 levels was observed. Furthermore, electron-microscopic findings in the kidneys showed mesangial cell proliferation and mesangial matrix expansion which might be caused by diabetic nephropathy. The PGI(2) derivative reduced urinary albumin and NAG levels in STZ-induced rats. It was considered, therefore, that the PGI(2) derivative is effective in diabetic nephropathy. As the PGI(2) derivative also reduced renal tissue ET-1 levels, improvement of diabetic nephropathy partially was considered to result from the reduction of renal tissue ET-1 levels. CONCLUSION: In STZ-induced rats, increased serum ET-1 levels and a tendency to increase in renal tissue ET-1 levels were associated with increases in urinary albumin and NAG levels, and these levels were decreased by a PGI(2) derivative. These findings suggested that increased ET-1 concentrations assist development and progression of diabetic nephropathy, especially diabetic microangiopathy, and the PGI(2) derivative may be effective for inhibition of diabetic microangiopathy mediated by reduction of ET-1 concentrations.     

Effect of starvation on endocrine cells in the rat stomach

The influence of food deprivation on gastric G- and D-cells and on parietal cells was studied in the rat. In fed controls and groups of rats fasted for 12 and 96 h G-, D- and parietal cell densities, somatostatin and gastrin concentration in antral and fundic specimens and serum gastrin were compared. Gastrin in antral mucosa, serum gastrin, G-cell density as well as antral D-cell density decreased in long-term fasted rats by 52%, 90%, 58% and 42%, respectively. Fundic D-cell density remained unchanged. After 96 h starvation somatostatin concentration slightly increased in antral mucosa (+35%; P less than 0.05), but decreased in fundic mucosa (-40%; P less than 0.05). Parietal cell density was not influenced by prolonged fasting. These findings demonstrate that changes in D-cell morphology and mucosal somatostatin content are not parallel and that the rat gastric D-cell is less dependent on food in the gastric lumen than the G-cell. The unaltered fundic D-cell density reflects the functional activity of gastric D-cell which has also been shown to be independent of the presence or absence of food.     

PGI、PGⅡ在胃癌组织中的表达及意义

目的：研究胃蛋白酶原I(PGI)、胃蛋白酶原Ⅱ(PGⅡ)在胃癌组织中的表达及意义。方法：将我院2011 年5 月至2013年10月 收治的上消化道疾病患者243 例纳入研究,根据胃镜及病理组织学结果,按照胃癌、慢性萎缩性胃炎、慢性非萎缩性胃炎、不典型 增生以及胃溃疡分为5 组,对照组为57 名来我院检查的健康的人群。应用酶联免疫法测定各组血清PGI、PGⅡ的含量并计算胃 蛋白酶原比值(PGR),比较胃癌患者手术前后血清PGI、PGⅡ的含量以及PGR,并通过ROC曲线下面积评价血清PGI、PGⅡ以及 PGR 诊断胃癌的效能。结果：与对照组比较,胃溃疡组PG I、PG II均明显升高,PGR 降低(P<0.05),慢性萎缩性胃炎组、不典型增生 组及胃癌组PGI、PGR均明显降低(P<0.05);与慢性萎缩性胃炎组比较,不典型增生组和胃癌组PGR 显著降低(P<0.05)。手术治疗 后,胃癌患者血清PGⅠ、PGⅡ含量较手术前明显下降(P＜0.05)。血清PGⅠ、PGⅡ以及PGR含量诊断胃癌的ROC 曲线下面积依 次为0.779、0.920 以及0.991。结论：胃癌患者血清PGI、PGR均明显降低,二者可用于初步筛查胃癌。     

A convenient model of severe, high incidence autoimmune gastritis caused by polyclonal effector T cells and without perturbation of regulatory T cells

Autoimmune gastritis results from the breakdown of T cell tolerance to the gastric H(+)/K(+) ATPase. The gastric H(+)/K(+) ATPase is responsible for the acidification of gastric juice and consists of an α subunit (H/Kα) and a β subunit (H/Kβ). Here we show that CD4(+) T cells from H/Kα-deficient mice (H/Kα(-/-)) are highly pathogenic and autoimmune gastritis can be induced in sublethally irradiated wildtype mice by adoptive transfer of unfractionated CD4(+) T cells from H/Kα(-/-) mice. All recipient mice consistently developed the most severe form of autoimmune gastritis 8 weeks after the transfer, featuring hypertrophy of the gastric mucosa, complete depletion of the parietal and zymogenic cells, and presence of autoantibodies to H(+)/K(+) ATPase in the serum. Furthermore, we demonstrated that the disease significantly affected stomach weight and stomach pH of recipient mice. Depletion of parietal cells in this disease model required the presence of both H/Kα and H/Kβ since transfer of H/Kα(-/-) CD4(+) T cells did not result in depletion of parietal cells in H/Kα(-/-) or H/Kβ(-/-) recipient mice. The consistency of disease severity, the use of polyclonal T cells and a specific T cell response to the gastric autoantigen make this an ideal disease model for the study of many aspects of organ-specific autoimmunity including prevention and treatment of the disease.     

Prostacyclin (PGI2) effects on anterior pituitary hormones in the rat in vivo.

Intravenous injection of 600 microgram PGE2 or PGI2 significantly increased serum LH and prolactin levels in estradiol treated ovariectomized rats. There was no effect on serum FSH concentration. PGE2 and PGI2 stimulated LH release in a non-dose dependent manner, while prolactin levels were positively correlated with the dose administered following PGI2 treatment. 6-keto-PGF1 alpha at a comparable dose had no effect on pituitary hormone levels. Subcutaneous administration of 1 mg/kg or 60 mg/kg PGI2 for seven days significantly depressed serum LH level both in male and female rats. These doses had no effect on serum FSH or prolactin levels.     

The unique ultrastructure of secretory membranes in gastric parietal cells depends upon the presence of H+, K+ -ATPase

Ion transporters play a central role in gastric acid secretion. To determine whether some of these transporters are necessary for the normal ultrastructure of secretory membranes in gastric parietal cells, mice lacking transporters for H+, K+, Cl-, and Na+ were examined for alterations in volume density (Vd) of basolateral, apical, tubulovesicular and canalicular membranes, microvillar dimensions, membrane flexibility, and ultrastructure. In mice lacking Na+/H+ exchanger 1 (NHE1) or the Na+-K+-2Cl- cotransporter (NKCC1), the ultrastructure and Vd of secretory membranes and the secretory canalicular to tubulovesicular membrane ratio (SC/TV), a morphological correlate of secretory activity, were similar to those of wild-type mice. In mice lacking Na+/H+ exchanger 2 (NHE2) or gastric H+, K+ -ATPase alpha- or beta-subunits, the SC/TV ratio and Vd of secretory membranes were decreased, though canaliculi were often dilated. In H+, K+ -ATPase-deficient parietal cells, canalicular folds were decreased, normally abundant tubulovesicles were replaced with a few rigid round vesicles, and microvilli were sparse, stiff and short, in contrast to the long and flexible microvilli in wild-type cells. In addition, microvilli of the H+, K+ -ATPase-deficient parietal cells had centrally bundled F-actin filaments, unlike the microvilli of wild-type cells, in which actin filaments were peripherally positioned concentric to the plasmalemma. Data showed that the absence of H+, K+ -ATPase produced fundamental changes in parietal cell membrane ultrastructure, suggesting that the pump provides an essential link between the membranes and F-actin, critical to the gross architecture and suppleness of the secretory membranes.     

Effect of genistein supplementation on tissue genistein and lipid peroxidation of serum, liver and low-density lipoprotein in hamsters

The aim of this study was to investigate the effects of genistein supplementation in a vitamin E-deficient diet on the genistein concentrations and the lipid oxidation of serum, liver and low-density lipoprotein (LDL) of hamsters. Thirty-six male hamsters were randomly divided into three groups and fed a vitamin E-deficient semisynthetic diet (AIN-76) containing different levels of genistein, i.e., G0 (control group, genistein-free diet), G50 (50 mg genistein/kg diet) and G200 (200 mg genistein/kg diet) for 5 weeks. The concentrations of genistein in serum and liver significantly increased with the increase of genistein supplementation. The vitamin E contents in LDL were higher in hamsters fed G50 or G200 diets than in hamsters fed genistein-free diet. Genistein supplementation to hamsters significantly reduced the propagation rate during conjugated diene formation of LDL oxidation, and the lag time of LDL oxidation in hamsters fed G200 diets was significantly lower than that of G0 diets. In addition, genistein supplementation significantly raised serum total antioxidant capacity and decreased the thiobarbituric acid-reactive substances (TBARS) of LDL and liver in hamsters. However, no significant differences in TBARS were found in serum, irrespective of genistein addition. On the other hand, the relative contents of polyunsaturated fatty acids in LDL were decreased after genistein supplementation. There was a negative correlation between lag time and P/S ratio, and a positive correlation between lag time and vitamin E contents. These data demonstrate that genistein supplementation markedly increased its concentrations in body tissues and reduced oxidative stress of lipid oxidation of serum, liver and LDL.     

Perturbation of gastric mucosa in mice expressing the temperature-sensitive mutant of SV40 large T antigen. Potential for establishment of an immortalised parietal cell line

Gastric parietal cells have a unique secretory membrane system that undergoes a profound transformation when the parietal cell is stimulated to secrete acid. Understanding this process has been hindered by the lack of an immortalised parietal cell line. Here we have explored a strategy for the development of a parietal cell line by the generation of transgenic mice bearing the temperature-sensitive mutant of the SV40 large T antigen (SV40 tsA58) under the control of the regulatory sequences of the gastric H+/K+ ATPase beta-subunit (H/Kbeta-tsA58). Three H/ Kbeta-tsA58 transgenic mouse lines were established, namely 218, 224 and 228, all of which expressed the tsA58 T antigen in the gastric mucosa. Unexpectedly, the gastric mucosae of all lines were hypertrophic indicating that the temperature-sensitive large T antigen was partially active at 37 degrees C. Immunofluorescence together with light and electron microscopic studies revealed that mature parietal and zymogenic cells were absent in H/Kbeta-tsA58 transgenic lines 218 and 224, and small undifferentiated cells were the dominant cell type in the gastric units. On the other hand, a few mature parietal cells were detected in line 228 together with an increased proportion of undifferentiated cells and, normally rare, pre-parietal cells. As line 228 represented a rich source of pre-parietal cells, gastric cells from line 228 were isolated and cultured at 33 degrees C, the permissive temperature for tsA58. Gastric epithelial cells, expressing the T antigen, were maintained in culture for over 6 weeks. Upon a temperature shift to 39 C the cultured gastric cells developed characteristics of differentiated parietal cells, including the presence of a nascent canaliculus and dramatically increased production of the gastric H+/K+ ATPase beta-subunit. Therefore, this system shows the potential to generate an immature parietal cell line that can be induced to differentiate in vitro.     

Study of molecular mechanism of Prostaglandin E1 in inhibiting coronary heart disease

Prostaglandin E1 has been used clinically for improving heart diseases. In this study, we examined the effect of Prostaglandin E1 on blood lipid levels, heart protein and genes expression in coronary heart disease (CHD) rats. Female rats were fed either a control diet or hypercholesterolemic diet for 14 weeks. The feeding of a hypercholesterolemic diet (HCD) increased the serum TC, TG, and LDL-c levels, decreased the serum HDL-c, E2, P, FSH, LH and PRL levels in CHD rats. In addition, The feeding of a HCD diet markedly increased the content of serum TXA2, TXB2, and decreased the content of serum PGI2, and PGI2/TXA2, 6-Keto PGF1a. Furthermore, the feeding of a hypercholesterolemic diet markedly increased expression levels of myocardium Fas and Caspase-3 protein and mRNA levels, vascular endothelial growth factor and basic fibroblast growth factor mRNA, and decreased RyR2 mRNA in CHD rats. The feeding of Prostaglandin E1 for 14 weeks significantly reversed these abnormal biochemical indexes in rats. These findings suggest that Prostaglandin E1 play a obvious heart protective effect. The mechanisms may be related to restraining the excessive activation of Fas and Caspase-3 protein and modulating some gene expressions associated with CHD.     

Sonic hedgehog is associated with H+-K+-ATPase-containing membranes in gastric parietal cells and secreted with histamine stimulation

Sonic hedgehog (Shh) is found within gastric parietal cells and processed from a 45-kDa to a 19-kDa bioactive protein by an acid- and protease-dependent mechanism. To investigate whether Shh is associated with the parietal cell membrane compartment that becomes exposed to both acid and proteolytic enzymes during acid secretion, the cellular location of Shh within resting and stimulated gastric parietal cells was examined. Immunofluorescence microscopy of rabbit stomach sections showed that Shh colocalized predominantly with parietal and pit, not chief/zymogen or neck, cell markers. In resting and histamine-stimulated rabbit gastric glands Shh was expressed only in parietal cells close to H+-K+-ATPase-containing tubulovesicular and secretory membranes with some colocalizing with gamma-actin at the basolateral membrane. Gastric gland microsomal membranes were prepared by differential and sucrose gradient centrifugation and immunoisolation with an anti-H+-K+-ATPase-alpha subunit antibody. The 45- and 19-kDa Shh proteins were detected by immunoblot in immunopurified H+-K+-ATPase-containing membranes from resting and stimulated gastric glands, respectively. Incubating glands with a high KCl concentration removed Shh from the membranes. Histamine stimulated 19-kDa Shh secretion from gastric glands into the medium. In human gastric cancer 23132/87 cells cultured on permeable membranes, histamine increased 19-kDa Shh secretion into both apical and basolateral media. These findings show that Shh is a peripheral protein associated with resting and stimulated H+-K+-ATPase-expressing membranes. In addition, Shh appears to be expressed at or close to the basolateral membrane of parietal cells.