Retinoic acid regulates morphogenesis and patterning of posterior foregut derivatives

Retinoic acid (RA) is an embryonic signaling molecule regulating a wide array of target genes, thereby being a master regulator of patterning and differentiation in a variety of organs. Here we show that mouse embryos deficient for the RA-synthesizing enzyme retinaldehyde dehydrogenase 2 (RALDH2), if rescued from early lethality by maternal RA supplementation between E7.5 and E8.5, lack active RA signaling in the foregut region. The resulting mutants completely fail to develop lungs. Development of more posterior foregut derivatives (stomach and duodenum), as well as liver growth, is also severely affected. A primary lung bud is specified in the RA-deficient embryos, which fails to outgrow due to defective FGF10 signaling and lack of activation of FGF-target genes, such as Pea3 and Bmp4 in the epithelium. Specific Hox and Tbx genes may mediate these RA regulatory effects. Development of foregut derivatives can be partly restored in mutants by extending the RA supplementation until at least E10.5, but lung growth and branching remain defective and a hypoplastic lung develops on the right side only. Such conditions poorly restore FGF10 signaling in the lung buds. Explant culture of RALDH2-deficient foreguts show a capacity to undergo lung budding and early branching in the presence of RA or FGF10. Our data implicate RA as a regulator of gene expression in the early embryonic lung and stomach region upstream of Hox, Tbx and FGF10 signaling.     

尼日利亚热带雨林池塘中茄氏旗鳉的食性

本文逐月研究了尼日利亚Mfangmfangpond中茄氏旗鳉全年的食性。其食谱按优势多寡出现的次序分别是陆生无脊椎动物、大型植物、水生无脊椎动物、小型甲壳动物、沙粒和藻类。我们将膜翅目、鞘翅目和双翅目昆虫作为其食性的次级项,而全年都出现的有机体碎屑作为初级项。雄鱼较雌鱼捕食了更多的陆生无脊椎动物。茄氏旗在雨季有16项食物组成,但旱季只有7项。就相对重要性而言,陆生和水生无脊椎动物在旱季更大,而大型植物碎屑、小型甲壳动物、沙粒和藻类则在雨季更大。成鱼较幼鱼更多地以外源性无脊椎动物为食。雌鱼较雄鱼有更强的觅食能力;同样,成鱼较幼鱼的觅食能力强得多.     

Modes of Disintegration of Solid Foods in Simulated Gastric Environment

A model stomach system was used to investigate disintegration of various foods in simulated gastric environment. Food disintegration modes and typical disintegration profiles are summarized in this paper. Mechanisms contributing to the disintegration kinetics of different foods were investigated as related to acidity, temperature, and enzymatic effect on the texture and changes in microstructure. Food disintegration was dominated by either fragmentation or erosion, depending on the physical forces acting on food and the cohesive force within the food matrix. The internal cohesive forces changed during digestion as a result of water penetration and acidic and enzymatic hydrolysis. When erosion was dominant, the disintegration data (weight retention vs. disintegration time) may be expressed with exponential, sigmoidal, and delayed-sigmoidal profiles. The different profiles are the result of competition among the rates of water absorption, texture softening, and erosion. A linear-exponential equation was used to describe the different disintegration curves with good fit. Acidity and temperature of gastric juice showed a synergistic effect on carrot softening, while pepsin was the key factor in disintegrating high-protein foods. A study of the change of carrot microstructure during digestion indicated that degradation of the pectin and cell wall was responsible for texture softening that contributed to the sigmoidal profile of carrot disintegration.     

SHIV感染恒河猴十二指肠黏膜活检组织病理学观察

目的使用消化内窥镜对SHIV感染恒河猴十二指肠黏膜进行观察。方法SHIV感染恒河猴,消化内镜检查并进行活检取材,对活检标本进行固定,石蜡包埋,常规HE染色镜检。结果内镜大体观察胃黏膜和十二指肠黏膜基本上完整平滑,1例胃黏膜有弥漫性白斑,3例有小面积的出血;光镜下十二指肠黏膜完整未见脱落,固有层中有散在分布的慢性炎细胞,活检取材最深可达黏膜下层,未见其他特异性病理改变。结论不同毒株,不同感染时间的SHIV感染恒河猴和对照恒河猴的十二指肠黏膜活检组织HE染色组织结构清晰,呈慢性炎症改变,病理形态上没有明显的差异。     

O1/O139新型霍乱疫苗口服免疫动物后的自动免疫保护及被动保护试验研究

O1／O139霍乱口服疫苗是一种新型疫苗。本文通过2种不同途径免疫动物,检测血清抗菌抗体和肠道分泌性IgA抗体以及保护力试验,并探讨了它们之间的关系。通过家兔肠袢试验和细胞四甲基偶氮唑盐(MTT)试验检测免疫后抗血清的被动保护作用。试验提示：在霍乱的保护性免疫应答中,除粘膜免疫可能占主导作用外,血清抗菌抗体也发挥了一定的作用。     

Role of endogenous prostacyclin in gastric ulcerogenic and healing responses—a study using IP-receptor knockout mice

Endogenous prostaglandins (PGs) play an important role in the cytoprotective and healing responses in the stomach, by altering various functions, i.e., an increase of the mucosal blood flow, yet the role of prostacyclin (PGI₂) and its receptor (IP-receptor) in these responses remains unclarified. In the present study, we used IP-receptor knockout mice [IP (−/−)] and examined the importance of IP-receptors in gastric ulcerogenic, cytoprotective and healing responses in these animals. The studies included the ulcerogenic response to cold-restraint stress, the cytoprotective response to a mild irritant (20 mM taurocholate: TC) and capsaicin, and the healing response of chronic gastric ulcers induced by thermo-cauterization. We first checked the absence of IP-receptors by examining the effect of cicaprost (a PGI₂ agonist, topical mucosal application) on gastric mucosal blood flow and found that this agent increased the mucosal blood flow in wild-type [WT (+/+)] mice but not in IP (+/−) mice. Cold-restraint stress (4 h) induced gastric lesions in both groups of mice, but the severity of damage was significantly greater in IP (−/−) mice. Prior p.o. administration of both TC and capsaicin exhibited a marked cytoprotection against HCl/ethanol-induced gastric damage in WT (+/+) mice, both responses being significantly mitigated in the presence of indomethacin. The adaptive cytoprotection induced by TC was similarly observed in IP (−/−) mice, while the capsaicin protection was totally attenuated in the animals lacking IP receptors. On the other hand, the healing of gastric ulcers was significantly delayed by daily administration of indomethacin in WT (+/+) mice. However, this process was not altered in IP (−/−) mice. These results suggest that endogenous PGI₂ is involved in the gastric ulcerogenic response to stress, but not in the healing of pre-existing gastric ulcers. In addition, PGI₂ and its receptors may play a crucial role in capsaicin-induced gastric protection but not in the adaptive cytoprotection-induced by mild irritants.     

戈登链球菌的生物学特性及在黏膜疫苗的应用

戈登氏链球菌是一种非致病性革兰氏阳性黏膜共生菌, 参与组成人类口腔正常菌群。它具有特殊的生物学特性, 非常适合作为黏膜疫苗的载体。了解戈登氏链球菌的生物学特性, 常用表达体系及该菌在黏膜疫苗的应用情况, 将为其黏膜疫苗的进一步研制提供重要参考。     

Ischemia mobilizes histamine but not pancreastatin from ECL cells of rat stomach: evidence for a cytosolic histamine compartment

Histamine in the rat stomach resides in enterochromaffin-like (ECL) cells and mast cells. The ECL cells are peptide-hormone-producing endocrine cells known to release histamine and chromogranin-A-derived peptides (such as pancreastatin) in response to gastrin. Ischemia (induced by clamping of the celiac artery or by gastric submucosal microinfusion of the vasoconstrictor endothelin) mobilizes large amounts of ECL-cell histamine in a burst-like manner. This report examines the ECL-cell response to ischemia and compares it with that induced by gastrin in rats. Arterial clamping (30 min) and gastric submucosal microinfusion (3 h) of endothelin, vasopressin, or adrenaline caused ischemia, manifested as a raised lactate/pyruvate ratio and mucosal damage. Whereas microinfusion of gastrin released both histamine and pancreastatin, ischemia mobilized histamine only. The mucosal concentrations of histamine and pancreastatin, the number and immunostaining intensity of the ECL cells, and the ultrastructure of the ECL cells were unchanged following ischemia. The long-term effects of ischemia and reperfusion (60-90 min) on gastric mucosa were examined in rats treated with the proton pump inhibitor omeprazole for 4 days. The activity of the ECL cells was suppressed (reflected in low histamine-forming capacity) but returned to normal within 1 week, illustrating the ability of the ECL cells to recover. We suggest that ischemia mobilizes cytosolic ECL-cell histamine without affecting the storage of histamine (and pancreastatin) in the secretory organelles and without causing lasting ECL-cell impairment.     

The remarkable geographical pattern of gastric cancer mortality in Ecuador

AimThis study was aimed to describe the gastric cancer mortality trend, and to analyze the spatial distribution of gastric cancer mortality in Ecuador, between 2004 and 2015.MethodsData were collected from the National Institute of Statistics and Census (INEC) database. Crude gastric cancer mortality rates, standardized mortality ratios (SMRs) and indirect standardized mortality rates (ISMRs) were calculated per 100,000 persons. For time trend analysis, joinpoint regression was used. The annual percentage rate change (APC) and the average annual percent change (AAPC) was computed for each province. Spatial age-adjusted analysis was used to detect high risk clusters of gastric cancer mortality, from 2010 to 2015, using Kulldorff spatial scan statistics.ResultsIn Ecuador, between 2004 and 2015, gastric cancer caused a total of 19,115 deaths: 10,679 in men and 8436 in women. When crude rates were analyzed, a significant decline was detected (AAPC: −1.8%; p < 0.001). ISMR also decreased, but this change was not statistically significant (APC: −0.53%; p = 0.36). From 2004 to 2007 and from 2008 to 2011 the province with the highest ISMR was Carchi; and, from 2012 to 2015, was Cotopaxi. The most likely high occurrence cluster included Bolívar, Los Ríos, Chimborazo, Tungurahua, and Cotopaxi provinces, with a relative risk of 1.34 (p < 0.001).ConclusionThere is a substantial geographic variation in gastric cancer mortality rates among Ecuadorian provinces. The spatial analysis indicates the presence of high occurrence clusters throughout the Andes Mountains.     

大鼠胃、胰CGRP阳性细胞的免疫组织化学观察

用免疫组织化学ABC法观察了大鼠胃,胰CGRP的分布。结果显示;（1）在大鼠胃内有大量的CGRP阳性神经纤维存在。未见CGRP阳性神经元。（2）大鼠胃窦部可见到少量CGRP阳性细胞：（3）在大鼠胰岛内有两种CGRP阳性内分泌细胞存在。