Molecular epidemiology and mechanisms of tigecycline resistance in clinical isolates of Acinetobacter baumannii from a Chinese university hospital.

Because of its remarkable ability to acquire antibiotic resistance and to survive in nosocomial environments, Acinetobacter baumannii has become a significant nosocomial infectious agent worldwide. Tigecycline is one of the few therapeutic options for treating infections caused by A. baumannii isolates. However, tigecycline resistance has increasingly been reported. Our aim was to assess the prevalence and characteristics of efflux-based tigecycline resistance in clinical isolates of A. baumannii collected from a hospital in China. A total of 74 A. baumannii isolates, including 64 tigecycline-nonsusceptible A. baumannii (TNAB) and 10 tigecycline-susceptible A. baumannii (TSAB) isolates, were analyzed. The majority of them were determined to be positive for adeABC, adeRS, adeIJK, and abeM, while the adeE gene was found in only one TSAB isolate. Compared with the levels in TSAB isolates, the mean expression levels of adeB, adeJ, adeG, and abeM in TNAB isolates were observed to increase 29-, 3-, 0.7-, and 1-fold, respectively. The efflux pump inhibitors (EPIs) phenyl-arginine-ß-naphthylamide (PAßN) and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) could partially reverse the resistance pattern of tigecycline. Moreover, the tetX1 gene was detected in 12 (18.8%) TNAB isolates. To our knowledge, this is the first report of the tetX1 gene being detected in A. baumannii isolates. ST208 and ST191, which both clustered into clonal complex 92 (CC92), were the predominant sequence types (STs). This study showed that the active efflux pump AdeABC appeared to play important roles in the tigecycline resistance of A. baumannii. The dissemination of TNAB isolates in our hospital is attributable mainly to the spread of CC92.

Novel action of 3,4-DAA ameliorating acute liver allograft injury.

The anti-allergic drug, N-(3,4-dimethoxycinnamonyl) anthranilic acid (3,4-DAA), is a synthetic anthranilic acid derivative that has been used therapeutically in Japan for many years. In this study, to investigate the effects of 3,4-DAA in allograft immunorejection model, liver orthotopic transplants were performed using inbred male Dark Agouti donors and Lewis rat recipients (allografts). The levels of indoleamine 2,3-dioxygenases (IDO) enzymic activities in five groups, allografts (control), dimethyl sulphoxide-treated group (vehicle control), 200 mg·kg(-1) ·day(-1) of 3,4-DAA-treated group and 200 mg·kg(-1) ·day(-1) of 3,4-DAA + 5 mg·ml(-1) of 1-methyl-D-tryptophan (1-MT)-treated group were confirmed by determination of L-kynurenine (L-Kyn) concentrations. The serum alanine aminotransferase levels in 3,4-DAA-treated rats significantly decreased compared with those in mock and control group, whereas treatment of 1-MT in allografts led to the opposite effect. Administration of 3,4-DAA reduced histological severity of allograft immunorejection, decreased serum levels of cytokines tumour necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), and raised serum levels of interleukin-10 (IL-10), suggesting that 3,4-DAA has both anti-inflammatory and anti-immunorejection properties through IDO in immune regulation and may therefore be useful in filling an unmet need, in the treatment of allograft immunorejection.

[Association of genetic polymorphisms in glutathione S-transferases M1 with hepatitis beta-related hepatocellular carcinoma].

OBJECTIVE: To investigate the association of genetic polymorphisms in glutathione S-transferases(GST) M1 with hepatitis beta-related hepatocellular carcinoma (HCC). METHODS: Genomic DNA was isolated from peripheral blood of HBsAg carriers, including 91 cases of HCC, 58 liver cirrhosis(LC), 63 chronic hepatitis B(CHB), and 134 normal controls. GSTM1 genotypes were detected by multiplex PCR. RESULTS: The null genotype of GSTM1 was significantly frequent in patients with HCC compared with controls (P<0.05), but there were no significant differences in frequency of GSTM1 null genotype among patients with liver cirrhosis, chronic hepatitis B and normal controls. Subjects carrying null genotypes of GSTM1 had higher risk of developing HCC compared with those carrying positive genotype (OR=1.81.95% CI=1.05 approximately equals 3.12). CONCLUSION: The GSTM1-null genotype may be associated with an increased risk of HCC, but not of CHB and LC.

High expression of 23 kDa protein of augmenter of liver regeneration (ALR) in human hepatocellular carcinoma.

BACKGROUND: Augmenter of liver regeneration (ALR) is an important polypeptide that participates in the process of liver regeneration. Two forms of ALR proteins are expressed in hepatocytes. Previous data have shown that ALR is essential for cell survival and has potential antimetastatic properties in hepatocellular carcinoma (HCC). AIMS: The study aimed to evaluate the expression levels of two forms of ALR proteins in HCC and their possible significance in HCC development. METHODS: Balb/c mouse monoclonal antibody against ALR protein was prepared in order to detect the ALR protein in HCC by Western blotting and immunohistochemistry. ALR mRNA expression levels were measured by real-time polymerase chain reaction in HCC tissues and compared to paracancerous liver tissues in 22 HCC patients. RESULTS: ALR mRNA expression in HCC liver tissues (1.51×10(6) copies/µL) was higher than in paracancerous tissues (1.04×10(4) copies/µL). ALR protein expression was also enhanced in HCC liver tissues. The enhanced ALR protein was shown to be 23 kDa by Western blotting. Immunohistochemical analysis showed that the 23 kDa ALR protein mainly existed in the hepatocyte cytosol. CONCLUSION: The 23 kDa ALR protein was highly expressed in HCC and may play an important role in hepatocarcinogenesis.

Both PI3K/Akt and ERK1/2 pathways participate in the protection by dexmedetomidine against transient focal cerebral ischemia/reperfusion injury in rats.

Dexmedetomidine (Dex) has been demonstrated to provide neuroprotection against ischemia/reperfusion (I/R) injury. However, the exact mechanism of this protection remains unknown. Here, we explored the neuroprotective effect of Dex in rats exposed to cerebral I/R-induced by middle cerebral artery occlusion (MCAO) and the role of phosphatidylinositol 3-kinase (PI3K)/Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), and glycogen synthase kinase-3ß (GSK-3ß) in this protective action. Adult male Sprague-Dawley rats were subjected to MCAO for 90 min followed by reperfusion for 24h and Dex (15 µg/kg, i.v.) was administered immediately after the onset of MCAO. The neurological deficit score, cerebral infarct volume, brain edema, and neuron survival were evaluated at 24h of reperfusion. The effect of Dex on p-Akt, p-ERK1/2 and p-GSK-3ß expression in the ischemic hemisphere was assayed by Western blot. Treatment of rats exposed to I/R with Dex caused not only marked reduction in the neurological deficit score, cerebral infarct volume, and brain edema (P <0.01 vs. I/R alone), but also a decrease in neuron death in hippocampal CA1 and cortex (P<0.01 vs. I/R alone). The Dex-induced increment of neuron survival in the ischemic CA1 and cortex was diminished by the PI3K inhibitor LY294002 and the MEK inhibitor U0126. The increasing expressions of p-Akt and p-ERK1/2 induced by Dex in the ischemic hemisphere were markedly inhibited by LY294002 (or wortmannin) and U0126 (or PD98059), respectively. The up-regulation of p-GSK-3ß by Dex in the ischemic hemisphere was significantly decreased by both LY294002 (or wortmannin) and U0126 (or PD98059). Our data demonstrated that treatment with Dex reduced cerebral injury in rats exposed to transient focal I/R, and this was mediated by the activation of the PI3K/Akt and ERK1/2 pathways as well the phosphorylation of downstream GSK-3ß.

Activation of Akt and cardioprotection against reperfusion injury are maximal with only five minutes of sevoflurane postconditioning in isolated rat hearts.

It had been proved that administration of sevoflurane for the first two minutes of reperfusion effectively protects the heart against reperfusion injury in rats in vivo. Our aim was to investigate the duration of effective sevoflurane administration and its underlying mechanism in isolated rat hearts exposed to global ischemia/reperfusion (I/R) injury. Adult male Sprague-Dawley rats were randomly divided into six groups (n=12): a sham-operation group, an I/R group, and four sevoflurane postconditioning groups (S2, S5, S10, and S15). In the S2, S5, S10, and S15 groups, the duration times of sevoflurane administration were 2, 5, 10, and 15 min after the onset of reperfusion, respectively. The isolated rat hearts were mounted on the Langendorff system, and after a period of equilibrium were subjected to 40 min global ischemia and 120 min reperfusion. Left ventricular (LV) hemodynamic parameters were monitored throughout each experiment and the data at 30 min of equilibrium and 30, 60, 90, and 120 min of reperfusion were analyzed. Myocardial infarct size at the end of reperfusion (n=7 in each group) and the expression of myocardial phosphorylated Akt (p-Akt) after 15-min reperfusion were determined in a duplicate set of six groups of rat hearts (n=5 in each group). Compared with the I/R group, the S5, S10, and S15 groups had significantly improved left ventricular end-diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), and the maximal rate of rise or fall of the LV pressure (±dP/dtmax), and decreased myocardial infarct size (P<0.05), but not the S2 group. After 15 min of reperfusion, the expression of p-Akt was markedly up-regulated in the S5, S10, and S15 groups compared with that in the I/R group (P<0.05), but not in the S2 group. Sevoflurane postconditioning for 5 min was sufficient to activate Akt and exert maximal cardioprotection against I/R injury in isolated rat hearts.

Hypercholesterolemia blocked sevoflurane-induced cardioprotection against ischemia-reperfusion injury by alteration of the MG53/RISK/GSK3ß signaling.

BACKGROUND: Recent studies have demonstrated that volatile anesthetic preconditioning confers myocardial protection against ischemia-reperfusion (IR) injury through activation of the reperfusion injury salvage kinase (RISK) pathway. As RISK has been shown to be impaired in hypercholesterolemia, we investigate whether anesthetic-induced cardiac protection was maintained in hypercholesterolemic rats. METHODS: Normocholesteolemic or hypercholesterolemic rat hearts were subjected to 30 min of ischemia and 2 h of reperfusion. Animals received 2.4% sevoflurane during three 5 min periods with and without PI3K antagonist wortmannin (10 µg/kg, Wort) or the ERK inhibitor PD 98059 (1 mg/kg, PD). The infarct size, apoptosis, p-Akt, p-ERK1/2, p-GSK3ß were determined. RESULTS: Two hundred and six rats were analyzed in the study. In the healthy rats, sevoflurane significantly reduced infarct size by 42%, a phenomenon completely reversed by wortmannin and PD98059 and increased the phosphorylation of Akt, ERK1/2 and their downstream target of GSK3ß. In the hypercholesterolemic rats, sevoflurane failed to reduce infarct size and increase the phosphorylated Akt, ERK1/2 and GSK3ß. In contrast, GSK inhibitor SB216763 conferred cardioprotection against IR injury in healthy and hypercholesterolemic hearts. CONCLUSIONS: Hyperchoesterolemia abrogated sevoflurane-induced cardioprotection against IR injury by alteration of upstream signaling of GSK3ß and acute GSK inhibition may provide a novel therapeutic strategy to protect hypercholesterolemic hearts against IR injury.

[HBV transinfected enhances the PD-L expression of cytokines stimulating].

OBJECTIVE: To investigate whether the PD-L expression in the liver cell lines transinfected with HBV (HepG2.2.15 cells) can be up-regulated after cytokines stimulating. METHODS: To apply the liver cell lines (HepG2 cells and HepG2.2.15 cells) as a model, the cells were stimulated with IL-4, IFN-alpha and IFN-gamma (final concentration were 10 ng/ml, stimulated for 12 hours) and RT-PCR was carried out to determine the PD-L expression before and after cytokines stimulating. RESULTS: Whether or not transinfected with HBV, IFN-alpha and IFN-gamma both can induce the liver cell lines (HepG2 cells and HepG2.2.15 cells) PD-L1 expression while IL-4 can not; IL-4, IFN-alpha, IFN-gamma all can induce the PD-L2 expression in HepG2.2.15 cells which was transinfected with HBV, only IFN-gamma can induce the PD-L2 expression in HepG2 cells which was not transinfected with HBV. CONCLUSION: IFN-alpha, IFN-gamma both can induce the PD-L1 expression in HepG2 cells and HepG2.2.15 cells, while it is easy for cytokines to induce the PD-L2 expression in HepG2.2.15 cells which was transinfected with HBV, this may provide a potential mechanism of the molecular basis for chronic HBV infection.