MiR-210 protects cardiomyocytes from OGD/R injury by inhibiting E2F3.

OBJECTIVE: To detect the change in miRNA-210 expression of cardiomyocytes under hypoxia/reoxygenation status. Also, the effect of miR-210 on the apoptosis of cardiomyocytes induced by oxygen-glucose deprivation/reperfusion (OGD/R) and its mechanism through establishing the OGD/R injury model of primary cardiomyocytes in this experiment were investigated. MATERIALS AND METHODS: The cell model of OGD/R injury was established. The cell apoptosis in each group was detected by methyl thiazolyl tetrazolium (MTT) assay and detection of Caspase-3 activity. The change in miR-210 expression in each group was detected by Real-time fluorescence quantitative polymerase chain reaction (PCR). The high-expression and low-expression miR-210 models were established through the transient transfection of miR-210 mimic and inhibitor to detect the relevant indexes of cell apoptosis. At the same time, changes in mRNA and protein expressions of E2F3 were detected by RT-PCR and Western blotting, respectively. The E2F3 overexpression vector was constructed, and the overexpression vector plasmid and miR-210 mimic were jointly transfected into the cells to detect the relevant indexes of cell apoptosis. RESULTS: After OGD/R treatment, the activity of Caspase-3 was increased, the survival of cardiomyocytes was significantly inhibited and the expression level of miR-210 was up-regulated in OGD/R injury. Transfection of miR-210 mimic for miR-210 overexpression could alleviate the OGD/R-induced cardiomyocyte injury, while the decrease of miR-210 expression could aggravate the apoptosis of cardiomyocytes. In addition, the high expression of miR-210 could inhibit the protein expression of E2F3, and co-transfection of E2F3 plasmid and miR-210 mimic could reverse the inhibiting effect of miR-210 on the apoptosis of cardiomyocytes. CONCLUSIONS: We confirmed that miR-210 can inhibit the OGD/R-induced apoptosis of cardiomyocytes, and miR-210, as an upstream factor, plays a protective role in cardiomyocytes through directly inhibiting the protein expression of its target gene E2F3.

Rnd3 haploinsufficient mice are predisposed to hemodynamic stress and develop apoptotic cardiomyopathy with heart failure.

Rho family guanosine triphosphatase (GTPase) 3 (Rnd3), a member of the small Rho GTPase family, has been suggested to regulate cell actin cytoskeleton dynamics, cell migration, and apoptosis through the Rho kinase-dependent signaling pathway. The biological function of Rnd3 in the heart is unknown. The downregulation of small GTPase Rnd3 transcripts was found in patients with end-stage heart failure. The pathological significance of Rnd3 loss in the transition to heart failure remains unexplored. To investigate the functional consequence of Rnd3 downregulation and the associated molecular mechanism, we generated Rnd3(+/-) haploinsufficient mice to mimic the downregulation of Rnd3 observed in the failing human heart. Rnd3(+/-) mice were viable; however, the mice developed heart failure after pressure overload by transverse aortic constriction (TAC). Remarkable apoptosis, increased caspase-3 activity, and elevated Rho kinase activity were detected in the Rnd3(+/-) haploinsufficient animal hearts. Pharmacological inhibition of Rho kinase by fasudil treatment partially improved Rnd3(+/-) mouse cardiac functions and attenuated myocardial apoptosis. To determine if Rho-associated coiled-coil kinase 1 (ROCK1) was responsible for Rnd3 deficiency-mediated apoptotic cardiomyopathy, we established a double-knockout mouse line, the Rnd3 haploinsufficient mice with ROCK1-null background (Rnd3(+/-/ROCK1-/-)). Again, genetic deletion of ROCK1 partially but not completely rescued Rnd3 deficiency-mediated heart failure phenotype. These data suggest that downregulation of Rnd3 correlates with cardiac loss of function as in heart failure patients. Animals with Rnd3 haploinsufficiency are predisposed to hemodynamic stress. Hyperactivation of Rho kinase activity is responsible in part for the apoptotic cardiomyopathy development. Further investigation of ROCK1-independent mechanisms in Rnd3-mediated cardiac remodeling should be the focus for future study.

Randomized comparison of two anti-emetic strategies in high-risk patients undergoing day-case gynaecological surgery.

BACKGROUND: Postoperative nausea and vomiting (PONV) is a significant cause of morbidity among patients undergoing general anaesthesia. The optimal strategy for prevention of PONV, however, remains unclear. This study compared two commonly used prophylactic strategies in high-risk, day-case, gynaecological surgery patients. METHODS: We conducted a randomized trial comparing sevoflurane combined with dolasetron (SD), with propofol-based total intravenous anaesthesia (TIVA) in 126 high-risk patients undergoing day-case gynaecological surgery. The primary endpoints included the incidence and severity of nausea or vomiting before discharge and the incidence of nausea or vomiting between discharge and 24 h. To identify the factors most predictive of a complete response (no PONV at any time within the 24 h period), multiple logistic regression models were fitted. RESULTS: Before discharge, there was no significant difference between the two treatment groups with respect to nausea and vomiting outcomes (P = 0.3). Post-discharge nausea and vomiting (PDNV), however, were significantly more common for patients in the TIVA group (nausea, P = 0.004 and vomiting, P = 0.03). Type of anaesthetic, adjusted for weight and anaesthesia duration was significantly associated with complete response (odds ratio = 2.7, 95% confidence interval = 1.15 to 6.4). CONCLUSIONS: Although both TIVA and dolasetron prophylaxis reduce the predicted rate of PONV in the early postoperative period, the anti-emetic effects of propofol are short-lived. A longer-acting drug such as dolasetron may therefore be necessary to prevent PDNV.

[Expression of Bacillus thuringiensis (Bt) crystal toxin gene in the chloroplast of tobacco].

The 3.5 kb wild-type Bt Cry I A(c) gene and its 3' truncated forms (2.1 kb, 1.8 kb) were placed under the control of plastid expression signals consisting of the strong light-induced psbA promoter and its 3' untranslated region with the aadA cassette (Prrn, aadA and psbA3') as a selectable marker. The resulting vectors pBT3, pBT8 and pBT22 also contain flanking tobacco plastid DNA homology regions to direct insertion of the Bt transgene into the tobacco plastid genome between psbA and trnK by homologous recombination. Transformed plastid genomes were selectively amplified by growing the cells on spectinomycin medium. Several independently transformed lines were obtained at last. The results of Southern and Western blot demonstrated that these three kinds of Bt genes had been introduced into tobacco plants, and their filial generations are resistant to spectinomycin. Insecticidal activity assay with transgenic tobacco leaves indicate that some plants have strong toxicity to cotton bollworm. This is the first report in China that Bt gene has been introduced and successfully expressed in the chloroplast of higher plants.

[Specific curative effects of nitrosourea drugs on tumor cells with Mer--phenotype in Chinese].

O6-Methylguanine DNA methyltransferase (O6-MT) activity and cellular sensitivity to nitrosourea drugs of 10 kinds of tumor cell strains derived from Chinese patients were measured by 3H radioactivity and colony-forming ability, respectively. The results in vitro showed that nimustine (Nim) 25 micrograms.ml-1 and carmustine (Car) 20 micrograms.ml-1 exhibited specific killing effects on Mer-phenotype tumor cells characterized by low O6-MT activity. In vivo both Nim and Car (25 mg.kg-1.wk-1 x 4 wk, ip) had specific curative ability to Mer- tumor cells implanted in nude mice. These findings suggested that assay of O6- MT activity in tumor biopsy could be used as a predictable guide to human tumor chemotherapy with nitrosourea compounds.

O6-methylguanine-DNA methyltransferase and human cancer chemotherapy.

Two kinds of human tumor cell strains having different activity of O6-methylguanine-DNA methyltransferase (O6-MT) were transplanted into nude mice. Then the mice were injected intraperitoneally with bifunctional alkylating agent 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU). The tumors with low O6-MT activity were quickly suppressed or cured. The result suggests that some tumors, if provisionally determined with low O6-MT activity, might be efficiently cured by treatment with ACNU. This probably opens a new way for human cancer chemotherapy.