Cyclic diguanylate (c-di-GMP) is a ubiquitous second messenger present in a wide variety of bacteria, which is responsible for cell differentiation, biofilm formation, pathogenic factor generation, and so on. The level of c-di-GMP in bacteria is regulated by two opposing active domains, diguanylate cyclase (DGC) and phosphodiesterase (PDE), which are present in the same bifunctional protein, and in charge of the synthesis and the degradation of c-di-GMP, respectively. The target of c-di-GMP in the bacterial cell consists of PilZ domain and GEMM riboswitch, the only riboswitch that involved in signal transduction. This article gives an overview of c-di-GMP, focusing on its metabolic pathway, regulatory mechanism, biological function of c-di-GMP, and the synthesis of c-di-GMP analogues and their biological activity.

BACKGROUND: Hypogonadism happens gradually with body aging. Traditional Chinese medicine views that deficiency of essential qi is the chief reason for body aging. OBJECTIVE: To observe the influence of tiannianyin, the Chinese herb , on serum testosterone, superoxide dismutase (SOD) activity in testicular tissue and expression of proliferating cell nuclear antigen of spermatogenic cells in testes in subacute senile rats induced by D-galactose. DESIGN: Randomized controlled experiment. SETTING: Basic Medicine Institute of Chengde Medical College. MATERIALS: The experiment was perlormed in Basic Medicine Institute of Chengde Medical College from April to July 2003, in which, 40 adult male SD rats were employed and randomized into 4 groups, 10 rats in each .In normal group, no any management was done. In model group, medication group and negative control, D-galactosie was used for abdominal injection continuously at 200 mg (kg·d), once a day, totally for 40 days to prepare the model of subacute senile animal. In model group, no any management was done after modeling success. In medication group, gastric infusion with tiannianyin. Tiannianyin was administrated everyday after modeling success, once a day, totally for 30 days. In negative control, gastric infusion with physiological saline of same dosage was administrated after modeling success for same days. METHODS: Enzyme linked immunosorbent assay (ELISA) was used for determination of serum testosterone content, xanthine oxidase assay was used for determination of SOD activity in testicular tissue and immunohistochemical method was used to observe expression of proliferating cell nuclear antigen in rats of every group. MAIN OUTCOME MEASURES: ① serum testosterone content; ② SOD activity in testicular tissue; ③ expression of proliferating cell nuclear antigen of spermatogenic cells. RESULTS: Forty rats all entered result analysis. ① Serum testosterone content: That in model group was lower than normal group(P ＜ 0.05), and that in medication group was higher than model group(P ＜ 0.05). ② SOD activity in testicular tissue: That in model group was lower remarkably than normal group(P ＜ 0.01), and that in medication group was higher remarkably than model group(P ＜ 0.01). ③ Expression of proliferating cell nuclear antigen of spermatogenic cells: That in model group was lower than normal group(P ＜ 0.05), and that in medication group was higher remarkably than model group(P ＜ 0.05). CONCLUSION: Tiannianyin delays degeneration of reproductive function and aging of certain degree.

Objective To investigate the effect of ampelopsin on apoptosis induction and cell growth inhibition in Human Colon cancer SW480 cells in vitro.Methods Treated with ampelopsin at several concentrations, MTT and flow cytometry was used to detect the inhibition rate and apoptotic rate of SW480 cells.Western-blot was used to investigate expression of Bcl-2 family pro-tein.Results Significant difference of cell growth inhibition rate was observed among all groups after treated with ampelopsin ( p<0.05).Cell growth inhibition rate in the low -dosage group was significantly high than that in median and high -dosage group (p<0.05), while no marked difference was observed between the median and high groups (p>0.05).The similar results were observed in the experiment on apoptosis induction.Level of Bcl-xL was significantly up-regulated.Level of Bax, Bid, Caspase-3, p-Ca-pase-9 and Caspase-9 was significantly down-regulated after treatment of ampelopsin.Conclusion Ampelopsin can inhibit cell growth and induce apoptosis of SW480.Bcl-2 family protein might be involved in the progress.

Objective To investigate the damage of hippocampal neurons induced by chronic cerebral ischemia in the rats,and to clarify its mechanism.Methods 90 healthy adult male SD rats were randomly divided into sham operation group (n=30 ) and experimental group (n=60 ). The chronic cerebral ischemia rat models were established by permanently ligating the common carotid arteries on both sides of the rats in experimental group.The rats in sham operation group were established by incising the cervical median,only the common carotid arteries on both sides were separated without ligating. The rats in sham operation group and experimental group were respectively sacrificed at the 7th,14th and 21st day after operation.At each time point 10 rats in sham operation group and 20 rats in experimental group were selected and sacrificed.Immunohistochemistry staining was used to observe the dynamic changes of the expression levels of choline acetyltransferase(ChAT)in hippocampus neurons, and TA-FE method was used to observe the dynamic changes of hippocampal microvascualr architecture. MiVnt image analytical system was used to quantitatively analyze the immunohistochemistry result,the microvessel density (MVD)and micorvessel area density (MVA)of horizontal part of hippocampus in the rats. Results Compared with sham operation group,the ChAT expression levels in hippocampus neurons of the rats in experimental group at different time points were significantly decreased(P<0.05);and with the prolongation of time,the ChAT expression levels were gradually decreased;the ChAT expression level in 14-day experimental group was significantly lower than that in 7-day experimental group (P<0.05 );the ChAT expression level in 21-day experimental group was significantly lower than those in 7-day and 14-day experimental groups(P<0.05).The MVD and MVA of hippocampus of the rats in experimental group at different time points were obviously decreased compared with sham operation group(P<0.05);the MVA was gradually decreased with the prolongation of time, and the MVA of hippocampus of the rats in 21-day and 14-day experimental groups were obviously decreased compared with 7-day experimental group(P<0.05);the MVD was gradually decreased with the prolongation of time,the MVD of hippocampus of the rats in 21-day and 14-day experimental groups was obviously decreased compared with 7-day experimental group(P<0.05);the MVD of hippocampus of the rats in 21-day experimental group was obviously decreased compared with 14-day experimental group(P<0.05).Conclusion Chronic cerebral ischemia can lead to the progressive decrease of the ChAT expression level,MVD and MVA of hippocampus of the rats to aggravate gradually the learning and memory dysfunction, which may be one of the reasons of vascular dementia.

To detect the expression of p16 protein and Ki-67 antigen in gastric mucosa-associated lymphoid tissue lymphoma(MALTL)and normal gastric mucosa and to investigate the clinical significance of their expression in the occurrence and development of gastric MALTL.Methods 47 samples of gastric MALTL diagnosed pathologically in the department of pathology of the PLA General Hospital from March 1993 to June 2005 were collected.By using immunohistochemial methods,the expression of p16 protein and Ki-67 antigen was detected in 20 samples of normal gastric tissue and the 47 samples of gastric MALTL.Results The positive rate of p16 protein Was 21.3%(10/47)and 90.0% in gastric MALTL and normal gastric tissue respectively.The positive rate of p16 protein in gastric MALTL was lower than that in normal gastric tissue(P<0.05).The expression of p16 was related to the degree of lymph node metastasis.The positive rate of Ki-67 labelling index(LI)in gnstric MALTL was hiigher than that in normal gastric tissue.A negative correlation was found between the expression of p16 protein and Ki-67 LI(P<0.05). Conclusions Detection p16 and Ki-67 may help to predict the possibility of lymph node metastasis and prognosis in gastric MALTL.

Objective To evaluate the clinical efficacy and safety of domestic BuMA biodegradable drug eluting coronary stent in elderly coronary heart disease patients over 75 years old with shortened duration of clopidogrel treatment. Methods 100 elderly patients who received coronary angiography and PCI were included, and they were randomly divided into the observation group ( n=50, received oral clopidogrel for 9 months) and the control group (n=50, received oral clopidogrel for 12 months). The occurance of angina pectoris, AMI, bleeding events and the results of control angiography were compared between the two groups after 12 months of follow-up. Results All the 100 patients were followed up in 12 months after discharge. 4 patients ( 8. 0%) in the observation group and 3 patients ( 6. 0%) in the control group had recurrent angina. Control coronary angiography 12 months later showed no restenosis in the stents. There was no significant difference between the two groups in the recurrence of angina pectoris and coronary stent restenonsis. No acute myocardial infarction,cliniacl bleeding events and late stent thrombosis occurred in the two groups. Conclusions The application of the domestic BuMA biodegradable drug eluting stent for the treatment of coronary heart disease patients over 75 years old is safe and effective with shortened duration of clopidogel treatment.

Objective To investigate the side effects of a new supramolecular drug-platinum compound CCP on the cardiovascular system,respiratory system and neuropsychological system of healthy rat.Methods After abdominal anaesthesia with 4.0 ml/kg of 10%chloral hydrate.the rats were injected with10,20,40 ms/ks CCP respectively,and then the life indexes,including blood pressure,heart rate,electrocardiogram,respiratory rate and depth were recorded through single femoral and tracheal intubations and so to non-anaesthesia rats.Glucose injection was chosen as negative control and carboplatin(15 mg/kg)as positive control.Results After venous injection with CCP,glucose injection and carboplatin as the dosages as above respectively,the blood pressures of the tested rats are from(57.8±14.1)mm Hg to(86.2±8.1)mm Hg,heart rates are from(250.9±95.4)times/min to(356.7±47.7)times/min,respiratory rates are from(59.3±17.7)times/min to(95.7±26.0)times/min.No obvious changes of blood pressure,heart rate and respiration were observed after drug injection,t values are(0.02～1.96),(P＞0.05).Once of sporadically ventrieular premature beat was recorded in one rat of CCP and earboplatin groups and it is not dosage-dependent.There is no side effect of 40 ms/ks CCP in neuropsychological system and daily activity of non-anaesthesia rats.Conclusion CCP injection is safe in rat and there is no obvious change observed in the cardiovascular system,respiratory system,neuropsyehological system of healthy rat.

Objective To report the preliminary result of cylindrical abdominoperineal resection (cylindrical APR) and pelvic reconstruction with human acellular dermal matrix (HADM). Methods Cylindrical APR was performed in 13 consecutive patients with advanced very low rectal cancer between January 2008 and April 2009. The mesorectum was not dissected off the levator muscles at abdominal part of the operation, the perineal part of the operation was done in the prone position. The levator muscles were exposed circumferentiaUy. The coccyx and part of the 5th sacrum were dissected and Waldeyer" s fascia divided. The levator muscles were divided laterally on both sides from posterior to anterior. The remaining pelvic floor muscle fibers were divided just posterior to the transverse perineal muscles and the levator muscles were resected en bloc with the anus and lower rectum. The specimen was cylindrical. The pelvic defects were reconstructed with HADM. Results There was no bowel perforation, and all specimens were proved CMR negative by pathology. Perineal wounds were healed uneventfully. After 8 months" follow-up, no patient developed perineal wound breakdown, bulge or hernia. There was 1 patient developed perineal wound infection; one patient developed seroma and three with perineal pain. Five patients with short-term urinary retention recovered within 10 days. Conclusion Clinical APR and HADM pelvic reconstruction can reduce circumferential margin positive and rectum perforation rate, and made the procedure easier and safer without increasing complications.

Photoaffinity labeling is widely applied to demonstrate targets of small molecule ligands. In this paper, biotin photoaffinity labeled molecule with propargyl group 1 has been designed and synthesized, followed it's labeling of N2-acetyl-2'-O-propargyl guanosine 9 by "click chemistry". This technology presents delight development potential in labeling of second messenger cyclic nucleotide, antisense oligonucleotide or siRNA.

Objective To assess the effects of thalidomide on VEGF mRNA level in human breast cancer cell lines. Methods Breast cancer cells were treated with thalidomide for 24～72h, RT-PCR was uced to detect the level of VEGF mRNA expression. Results When the concentration of drug is 50μg/L,thalidomide strongly inhibited the level of VEGF mRNA expression. Conclusion Within certain concentration range of thalidomide can inhibit the level of VEGF mRNA expression in breast cancer cell.