Quercetin protects rat hepatocytes from oxidative damage induced by ethanol and iron by maintaining intercellular liable iron pool

Accumulating evidence has shown that ethanol-induced iron overload plays a crucial role in the development and progression of alcoholic liver disease. We designed the present study to investigate the potential protective effect of quercetin, a naturally occurring iron-chelating antioxidant on alcoholic iron overload and oxidative stress. Ethanol-incubated (100 mmol/L) rat primary hepatocytes were co-treated by quercetin (100 µmol/L) and different dose of ferric nitrilotriacetate (Fe-NTA) for 24 h. When the hepatic enzyme releases in the culture medium, redox status of hepatocytes and the intercellular labile iron pool (LIP) level were assayed. Our data showed that Fe-NTA dose dependently induced cellular leakage of aspartate transaminase and lactate dehydrogenase, glutathione depletion, superoxide dismutase inactivation, and overproduction of malondialdehyde) and reactive oxygen species (ROS) of intact and especially ethanol-incubated hepatocytes. The oxidative damage resulted from ethanol, Fe-NTA, and especially their combined treatment was substantially alleviated by quercetin, accompanying the corresponding normalization of intercellular LIP level. Iron in excess, thus, may aggravate ethanol hepatotoxicity through Fenton-active LIP, and quercetin attenuated ethanol-induced iron and oxidative stress. To maintain intercellular LIP contributes to the hepatoprotective effect of quercetin besides its direct ROS-quenching activity.

Decreased expression of p38 MAPK mediates protective effects of hydrogen sulfide on hepatic fibrosis

AIM

To investigate the in vitro and in vivo effects of hydrogen sulfide (H2S) on activated hepatic stellate cells (HSCs) and carbon tetrachloride (CCl4)-induced hepatic fibrosis rats. To explore the in vitro and in vivo expression of Phospho-p38, Phospho-Akt and NF-kB in HSCs treated with H2S.

MATERIALS AND METHODS

HSC-T6 cells were incubated and activated with 500 µg/L ferric nitrilotriacetate (Fe-NTA), and then were incubated with NaHS, an H2S-releasing molecule for 6, 12, 24 and 48 h. MTT assay was performed to detect cell viability. Propidium iodide (PI) staining was used to determine cell cycle by flow cytometry. Apoptosis was detected with Annexin-V FITC (fluorescein isothiocyanate) and PI (propidium iodide) double staining. Western blotting was performed to detect protein expressions of Phospho-p38, Phospho-Akt and NF-kB. Hepatic fibrosis model was established by intraperitoneal injection of CCl4 in male Wistar rats, and rats were randomly divided into three groups, including healthy control, rats treated with CCl4 + saline, and rats treated with CCl4 + NaHS. Immunohistochemistry analysis was performed to measure protein expression of Phospho-p38 and Phospho-Akt in rat hepatic samples.

RESULTS

NaHS inhibited the proliferation of Fe-NTA (nitrilotriacetic acid)-induced HSC-T6 cells in a dose-dependent way at 6, 12, 24 and 48 h. NaHS (500 µmol/L) induced G1 phase cell cycle arrest and promoted survival in Fe-NTA-induced HSC-T6 cells. NaHS decreased Phospho-p38 and increased Phospho-Akt expressions in Fe-NTA-induced HSC-T6 cells and CCl4-induced liver fibrosis rats.

CONCLUSIONS

Exogenous H2S inhibits activated HSC-T6 cells and induces cell cycle arrest and apoptosis. Decreased Phospho-p38 and increased Phospho-Akt expressions may mediate the anti-fibrosis effect by exogenous H2S.

Influence of indoor formaldehyde pollution on respiratory system health in the urban area of Shenyang, China

BACKGROUND

The decoration of interior spaces can lead to dangerous levels of indoor formaldehyde pollution. Exposure to indoor air pollution may be responsible for nearly 2 million deaths per year in developing countries.

OBJECTIVES

To assess the prevalence of indoor formaldehyde pollution caused by decoration and resultant respiratory system symptoms exhibited in exposed adults and children, due to indoor formaldehyde pollution caused by decoration.

METHODS

Survey sites were chosen and indoor formaldehyde concentrations determined according to the standard of formaldehyde in GB50325-2001. Logistic regression models were used to derive odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjusting for potential confounders for this survey.

RESULTS

Formaldehyde concentration was above the standard in 64% of Shenyang City. Some adults surveyed complained of common respiratory system disorders, including coughing (11.8%), nasal irritation (39.2%), Heterosmia (14.51%), and throat irritation (25.27%); 12% of children suffered from asthma. The analysis identified formaldehyde pollution and ventilation frequency as risk factors for respiratory system disorders in both adults (OR=2.603, [95% CI: 1.770-3.828], OR=1.604, [95% CI: 1.146-2.244], respectively) and children (OR=4.250, [2.064-8.753], OR=1.831, [1.006-3.333], respectively).

CONCLUSION

The prevalence of common respiratory system disorders was related both to formaldehyde pollution and insufficient ventilation after decorating.

Pharmacological reduction of NEFA restores the efficacy of incretin-based therapies through GLP-1 receptor signalling in the beta cell in mouse models of diabetes

AIMS/HYPOTHESIS

Type 2 diabetes mellitus is associated with reduced incretin effects. Although previous studies have shown that hyperglycaemia contributes to impaired incretin responses in beta cells, it is largely unknown how hyperlipidaemia, another feature of type 2 diabetes, contributes to impaired glucagon-like peptide 1 (GLP-1) response. Here, we investigated the effects of NEFA on incretin receptor signalling and examined the glucose-lowering efficacy of incretin-based drugs in combination with the lipid-lowering agent bezafibrate.

METHODS

We used db/db mice to examine the in vivo efficacy of the treatment. Beta cell lines and mouse islets were used to examine GLP-1 and glucose-dependent insulinotropic peptide receptor signalling.

RESULTS

Palmitate treatment decreased Glp1r expression in rodent insulinoma cell lines and isolated islets. This was associated with impairment of the following: GLP-1-stimulated cAMP production, phosphorylation of cAMP-responsive elements binding protein (CREB) and insulin secretion. In insulinoma cell lines, the expression of exogenous Glp1r restored cAMP production and the phosphorylation of CREB. Treatment with bezafibrate in combination with des-fluoro-sitagliptin or exendin-4 led to more robust glycaemic control, associated with improved islet morphology and beta cell mass in db/db mice.

CONCLUSIONS/INTERPRETATION

Elevated NEFA contributes to impaired responsiveness to GLP-1, partially through downregulation of GLP-1 receptor signalling. Improvements in lipid control in mouse models of obesity and diabetes increase the efficacy of incretin-based therapy.

Complications associated with central and non-central venous catheters in a neonatal intensive care unit

OBJECTIVE

The objective of this study is to compare complication rates between peripherally inserted central catheters (PICCs) and peripherally inserted non-central catheters (PINCCs) in the neonatal intensive care unit (NICU).

STUDY DESIGN

A retrospective, observational study was conducted. The PICCs were catheters whose tip terminated in the vena cavae, and PINCCs were defined as those whose tip fell short of this location. Complication rates were assessed using generalized estimating equations modeling.

RESULT

A total of 91 PINCCs and 889 PICCs were placed in 750 neonates. In all, 44.0% of PINCCs had a major complication compared with 25.2% of PICCs (P=0.0001). The unadjusted (unadj.) complication rate among PINCCs was 51.7 per 1000 line days and 15.9 for PICCs (unadj. rate ratio: 3.25; 95% confidence interval (CI): 2.32, 4.55). After adjusting for multiple confounders, the risk remained significantly higher for PINCCs (adjusted odds ratio: 2.41; 95% CI: 1.33, 4.37).

CONCLUSION

The rate of associated complications with the use of PINCCs in the NICU population is more than twice that of the PICCs.

Reachability analysis of real-time systems using time Petri nets

Time Petri nets (TPNs) are a popular Petri net model for specification and verification of real-time systems. A fundamental and most widely applied method for analyzing Petri nets is reachability analysis. The existing technique for reachability analysis of TPNs, however, is not suitable for timing property verification because one cannot derive end-to-end delay in task execution, an important issue for time-critical systems, from the reachability tree constructed using the technique. In this paper, we present a new reachability based analysis technique for TPNs for timing property analysis and verification that effectively addresses the problem. Our technique is based on a concept called clock-stamped state class (CS-class). With the reachability tree generated based on CS-classes, we can directly compute the end-to-end time delay in task execution. Moreover, a CS-class can be uniquely mapped to a traditional state class based on which the conventional reachability tree is constructed. Therefore, our CS-class-based analysis technique is more general than the existing technique. We show how to apply this technique to timing property verification of the TPN model of a command and control (C2) system.

Resistive vibration exercise retards bone loss in weight-bearing skeletons during 60 days bed rest

Countermeasures are desirable to retard bone loss during long-term space flight. We evaluated the effect of an intervention protocol on bed rest-induced bone loss.

INTRODUCTION

We developed a resistive vibration exercise (RVE) platform to test if an intervention RVE protocol would be effective to protect bed rest-induced bone loss.

METHODS

Fourteen male subjects were assigned randomly to either the RVE group (n = 7) that performed daily supervised resistive vibration exercise or to the no any exercise control (CON) group (n = 7). Both dual-energy X-ray absorptiometry and peripheral quantitative computed tomography were used to monitor changes in bone mineral density.

RESULTS

RVE significantly prevented bone loss at multiple skeletal sites, including calcaneus, distal tibia, hip, and lumbar spine (L2-L4). The ratio of urinary calcium and creatinine was found higher after starting bed rest in CON group while no significant changes were observed in RVE group. No significant temporal change was found for osteocalcin-N during and after bed rest in CON group. However, a significant increase was shown after bed rest in RVE group. In both groups, the urinary concentration of bone resorption markers, such as C-telopeptide of type I collagen (CTX-I) and deoxypyridinoline (DPD), were significantly elevated after bed rest. In the CON group, no significant temporal effect was found for hydroxyproline (HOP), CTX-I, and DPD during bed rest and the serum concentration of HOP and TGF-β significantly increased about 52.04% and 24.03%, respectively only after bed rest. However, all these markers tended to decrease in the RVE group.

CONCLUSIONS

Our results might imply that the intervention of RVE retarded bone loss induced by simulated microgravity in humans that was mainly attributed to its anabolic effects.

Two novel mutations of the NCSTN gene in Chinese familial acne inverse

BACKGROUND

Acne inversa (AI; MIM 142690), or hidradenitis suppurativa (HS), is a type of autosomal-dominant genodermatosis caused by mutations in γ-secretase. The complex of γ-secretase is a transmembrane protease that catalyses the cleavage of a set of membrane proteins and is comprised of four subunits encoded by four genes, including PSEN1, PSENEN, NCSTN and APH1. However, mutations associated with AI vary significantly, and it is important to define the specific mutation with a particular AI patient.

OBJECTIVE

To determine specific mutations in the γ-secretase gene associated with two Chinese AI families.

METHODS

Two families of three generations with apparent AI symptoms were examined through proband analysis. Genomic DNAs of the family members and a cohort of 100 healthy individuals were isolated and subjected to polymerase chain reaction (PCR) and direct DNA sequencing.

RESULTS

Two heterozygous missense mutations, c.647A>C (p.Q216P) in the exon 6, and c.223G>A (p.V75I) in the exon 3 of the NCSTN gene, were identified in the two families respectively. No mutations were found in 100 healthy individuals.

CONCLUSIONS

We have identified two novel mutations within the NCSTN gene associated with AI.

Blocking p55PIK signaling inhibits proliferation and induces differentiation of leukemia cells

p55PIK, a regulatory subunit of phosphatidylinositol 3-kinases, promotes cell cycle progression by interacting with cell cycle modulators such as retinoblastoma protein (Rb) via its unique amino-terminal 24 amino-acid residue (N24). Overexpression of N24 specifically inhibits these interactions and leads to cell cycle arrest. Herein, we describe the generation of a fusion protein (Tat transactivator protein (TAT)-N24) that contains the protein transduction domain and N24, and examined its effects on the proliferation and differentiation of leukemia cells. TAT-N24 not only blocks cell proliferation but remarkably induces differentiation of leukemia cells in vitro and in vivo. Systemically administered TAT-N24 also significantly decreases growth of leukemia cell tumors in animal models. Furthermore, overexpression of p55PIK in leukemia cells leads to increased proliferation; however, TAT-N24 blocks this effect and concomitantly induces differentiation. There is significant upregulation of p55PIK mRNA and protein expression in leukemia cells from patients. TAT-N24 inhibits cell cycle progression and induces differentiation of bone marrow cells derived from patients with several different types of leukemia. These results show that cell-permeable N24 peptide induces leukemia cell differentiation and suggest that p55PIK may be a novel drug target for the treatment of hematopoetic malignancies.

¹H NMR-based metabonomics in brain nucleus accumbens and striatum following repeated cocaine treatment in rats

Studies have shown a few cerebral metabolites modified by cocaine in brain regions; however, endogenous metabolic profiling has been lacking. Ex vivo (1)H NMR (hydrogen-1 nuclear magnetic resonance) spectroscopy-based metabonomic approach coupled with partial least squares was applied to investigate the changes of cerebral metabolites in nucleus accumbens (NAc) and striatum of rats subjected to cocaine treatment. Our results showed that both single and repeated cocaine treatment can induce significant changes in a couple of cerebral metabolites. The increase of neurotransmitters glutamate and gamma-amino butyric acid (GABA) were observed in NAc and striatum from the rats repeatedly treated with cocaine. Creatine and taurine increased in NAc whereas taurine increased and creatine decreased in striatum after repeated cocaine treatment. Elevation of N-acetylaspartate in NAc and striatum and decrease of lactate in striatum were observed, which may reflect the mitochondria dysregulation caused by cocaine; moreover, alterations of choline, phosphocholine and glycerol in NAc and striatum could be related to membrane disruption. Moreover, groups of rats with and without conditioned place preference (CPP) apparatus are presenting difference in metabolites. Collectively, our results provide the first evidence of metabonomic profiling of NAc and striatum in response to cocaine, exhibiting a regionally-specific alteration patterns. We find that repeated cocaine administration leads to significant metabolite alterations, which are involved in neurotransmitter disturbance, oxidative stress, mitochondria dysregulation and membrane disruption in brain.