Tweenty-one SD rats with streptozotocin-induced diabetes were investigated for the influence of magnesium in cAMP level in the retina of the diabetic rats. The diabetic rats were divided into 3 groups: group 1, drinking tap hehwater; group 2, drinking 0.5% MgSO4 solution and group 3, receiving intramuscular MgSO4(0.1g/kg) once a month. In addition, group 4, a controlgroup of normal nondiabetic rats fed with tap water. In aperiod of 5 months examination, the growth and health conditions of diabetic rats were found to be nearly normal in group 2, 3 and 4, manifested by gaining weight and soft, smooth hairs on the skin, in contrast with loss in weight, rough hairs and even dying of infection in 2 of the diabetic rats in group 1. furthermore, the level of cAMP content in retina was found significantly higher in the diabetic rats taking Mg++ in spite of the route of administration(group 2, 3), as well as in the control group(group 4) than that of the diabetic rats which were fed with tap water. These results demonstrated that Mg++ might play an important role in improving the metabolism of diabetic rats including the retinal tissue by influencing the level of cAMP content, which is necessary in nuclear acid metabolism, protein synthesis, proliferation and differentiation, and other intracellular metabolic processes. （Chin J Ocul Fundus Dis,1992,8:141-143）
The retina of SD rats was incubated in four types of the Eagle solution respectively. The results showed the cAMP level of retinas was the lowest in the hGnMg(high glucose with normal magnesium) solution but the cAMP level was significantly increased in the hGhMg(high glucose with high magnesium) and higher than that of normal control group. The cAMP level was the highest in the nGhMg(normal glucose with high magnesium). The results suggested that magnesium might play an important role in maintaining the normal metabolism of glucose of the retinal tissue. （Chin J Ocul Fundus Dis,1992,8:138-140）
As an essential trace element for most organisms, iron is an important cofactor for various enzymes that performs key reactions. Siderophore has been considered as an important virulence factor. The cAMP receptor protein is an integral regulator, directly or indirectly involved in the regulation of siderophores-related genes in some prokaryotes and eukaryotes. This paper briefly introduces the cAMP receptor protein, and reviews the regulation of cAMP receptor protein on siderophores-related virulence genes of Klebsiella pneumoniae, Yersinia pestis, Vibrio vulnificus and Cryptococcus neoformans, in order to lay a theoretical foundation for clarifying the regulation mechanism of cAMP receptor protein on siderophores and provide a reference for pathogenic bacteria virulence control and clinical prevention.
The Dacron grafts seeded with autologous venous fragments were implanted into IVC of 13 canines as seeded group and the control grafts (8 cases), which were only preclotted with fresh blood. The amounts of cAMP and cGMP in serum and within platelet were measured. All of the specimens explanted at exsaguination were observed morphologically. The results shown that the total patency rate were 61.5% in seeded group, but 25.0% in control one and new endothelial lining formed at two weeks after implantation of the seeded grafts. The amounts of cAMP in serum and within platelet were higher in seeded group, but the amounts of cGMP were lower in serum and within platelet. These were in accordance with the results that the endothelialization of the grafts were complete in seeded group but not complete in control one. The results indicate that seeding Dacron with autologous venous fragment makes new endothelium formed at two weeks after implantation, increases the amounts of cAMP in serum and within platelet, but reduces the amounts of cGMP and thus improves graft patency rate.
【Abstract】ObjectiveTo investigate the effects of endogenous photodynamic therapy (PDT) on intracellular cAMP and cGMP concentrations of human colon carcinoma cell lines SW480. MethodsSW480 cells were divided into control group, light group, δaminolevulinic acid （ALA） group (ALA group) and endogenous PDT group (ALAPDT group). Intracellular cAMP and cGMP concentrations of each group were detected by radioimmunoassay at 30, 60, 90 and 120 min after irradiation. ResultsThere was a significant increase in intracellular cAMP concentration of ALAPDT group at 30 min after irradiation (P＜0.001) and sequent decrease, but intracellular cAMP concentrations of ALAPDT group at 60, 90 and 120 min after irradiation had no statistical difference than the other groups (Pgt;0.05). Intracellular cGMP concentration of different time point of each group was not significantly different. ConclusionThese results indicate that the cytoprotection of SW480 cell are produced by an instantaneous increase in the intracellular cAMP concentration while endogenous PDT is killing SW480 cell.
Objective To investigate the regulatory effects of miR-26a-5p on the osteogenic differentiation of adipose-derived mesenchymal stem cells (ADSCs) by regulating cAMP response element binding protein 1 (CREB1). Methods The adipose tissues of four 3-4 weeks old female C57BL/6 mice were collected and the cells were isolated and cultured by digestion separation method. After morphological observation and identification by flow cytometry, the 3rd-generation cells were subjected to osteogenic differentiation induction. At 0, 3, 7, and 14 days after osteogenic differentiation induction, the calcium deposition was observed by alizarin red staining, ALP activity was detected, miR- 26a-5p and CREB1 mRNA expressions were examined by real-time fluorescence quantitative PCR, and CREB1 protein and its phosphorylation (phospho-CREB1, p-CREB1) level were measured by Western blot. After the binding sites between miR-26a-5p and CREB1 was predicted by the starBase database, HEK-293T cells were used to conduct a dual-luciferase reporter gene experiment to verify the targeting relationship (represented as luciferase activity after 48 hours of culture). Finally, miR-26a-p inhibitor (experimental group) and the corresponding negative control (control group) were transfected into ADSCs. Alizarin red staining, ALP activity, real-time fluorescent quantitative PCR (miR-26a-5p) and Western blot [CREB1, p-CREB1, Runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN)] were performed at 7 and 14 days after osteogenic induction culture. Results The cultured cells were identified as ADSCs. With the prolongation of osteogenic induction culture, the number of calcified nodules and ALP activity significantly increased (P<0.05). The relative expression of miR-26a-5p in the cells gradually decreased, while the relative expressions of CREB1 mRNA and protein, as well as the relative expression of p-CREB1 protein were increased. The differences were significant between 7, 14 days and 0 day (P<0.05). There was no significant difference in p-CREB1/CREB1 between different time points (P>0.05). The starBase database predicted that miR-26a-5p and CREB1 had targeted binding sequences, and the dual-luciferase reporter gene experiment revealed that overexpression of miR-26a-5p significantly suppressed CREB1 wild-type luciferase activity (P<0.05). After 7 and 14 days of osteogenic induction, compared with the control group, the number of calcified nodules, ALP activity, and relative expressions of CREB1, p-CREB1, OCN, and RUNX2 proteins in the experimental group significantly increased (P<0.05). There was no significant difference in p-CREB1/CREB1 between the two groups (P>0.05). Conclusion Knocking down miR-26a-5p promoted the osteogenic differentiation of ADSCs by up-regulating CREB1 and its phosphorylation.