No description available.

The purpose of this investigation was to determine and characterise the anti-oxidant activity of the methanol extract of the leaves of Halleria lucida utilizing the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The methanol extract of the leaves of H. lucida displayed promising anti-oxidant activity with an IC50 value of 8.49±0.12 μg/ml and was subsequently subjected to activity-guided fractionation resulting in the isolation of a flavone-type flavonoid and phenylpropanoid glycoside, namely luteolin-5-O-β-D-glucoside and verbascoside (acteoside), respectively. Both compounds displayed promising anti-oxidant activities with IC50 values of 6.12±0.40 and 7.18±0.08 μg/ml for luteolin-5-O-β-D-glucoside and verbascoside, respectively. Furthermore, isobologram construction was undertaken to determine pharmacological interactions between the isolated molecules resulting in a concentration-dependent additive and antagonistic interaction being recognised.

No description available.

Investigations concerning metallothionein (MT) have covered 4 main areas. Initial studies were carried out to develop an immunocytochemical technique for the detection of MT. An indirect peroxidase technique was used to localise MT within the livers and kidneys of rats injected with CuSO4. An increase in immunocytochemical staining was observed following Cu injection which was consistent with the increase in MT-I concentrations as detected by RIA. To establish whether degradation of MT in vitro is influenced by prior exposure of protein to oxygen free radicals. (Cu,Zn)-MT with Cu:Zn ratio 1:1, purified from pig liver following injection with diethylamine copper oxyquinoline sulphonate (Cujec), was found to be extensively degraded after incubation with a free radical generating system (xanthine/xanthine oxidase) and subsequently with trypsin. However proteins with Cu:Zn ratios of 2:1 or 5:1 were not greatly affected. This indicates that an oxidative step may be involved in the degradation pathway and/or aggregation of MT but the magnitude of the effect is ultimately determined by the ratio of metals present within MT. To establish whether the turnover rate of hepatic CuMT is increased in vivo in animals subjected to oxidant stress. Iron overload was used to initiate oxidant stress in rats prior to injection of Cu using a mixture of Cujec and CuSO4. It could not be concluded, however, if in vivo degradation of CuMT was influenced by the application of iron-induced oxidant stress. Subcellular localisation of MT by fractionation of liver and kidney homogenates using preformed Percoll gradients did, however, demonstrate that MT was not associated with the lysosomal fraction but within the nuclear fraction in correlation with previous studies. To identify specific chelators for selective removal of Cu from CuMT in vitro and to establish the effect of administration of such chelators on the turnover of CuMT in vivo. Ammonium terathiomolybdate [(NH4)2MoS4] was incubated with (Cu,Zn)-MT and Cd, resulting in the complete removal of Cu from protein and replacement with Cd. The effect of this chelating action for Cu was then studied in vivo by administration of (NH4)2MoS4 to rats following injection of Cu using a mixture of Cujec and CuSO4. The turnover and degradation of induced CuMT, however, could not be said to be increased by the addition of the Cu chelator, (NH4)2MoS4, conclusively.

Light chain amyloidosis (AL) is associated with high mortality, especially in patients with advanced cardiovascular involvement. It is caused by toxicity of misfolded light chain proteins (LC) in vascular, cardiac, and other tissues. There is no treatment to reverse LC tissue toxicity. We tested the hypothesis that nanoliposomes composed of monosialoganglioside, phosphatidylcholine, and cholesterol (GM1 ganglioside-containing nanoliposomes [NLGM1]) can protect against LC-induced human microvascular dysfunction and assess mechanisms behind the protective effect.

Providing pretreatment prior RO filtration is essential to avoid biofouling and subsequent loss of membrane performances. Chlorine is known to degrade polymeric membrane, improving or reducing membrane efficiency depending on oxidation conditions. This study aimed to assess the impact of alternative disinfectant, NH2Cl, as well as secondary oxidants formed during chloramination of seawater, e.g. HOBr, HOI, or used in water treatment e.g. ClO2, O3, on membrane structure and performances. Permeability, total and specific rejection (Cl-, SO4 2-, Br-, Boron), FTIR profile, elemental composition were analyzed. Results showed that each oxidant seems to react differently with the membrane. HOCl, HOBr, ClO2 and O3 improved membrane permeability but decreased rejection in different extent. In comparison, chloramines resulted in identical trends but oxidized membrane very slowly. On the contrary, iodine improved membrane rejection e.g. boron, but decreased permeability. Reaction conducted with chlorine, bromine, iodine and chloramines resulted in the incorporation of halogen in the membrane structure. All oxidant except iodine were able to break amide bonds of the membrane structure in our condition. In addition, chloramine seemed to react with membrane differently, involving a potential addition of nitrogen. Chloramination of seawater amplified membrane performances evolutions due to generation of bromochloramine. Moreover, chloramines reacted both with NOM and membrane during oxidation in natural seawater, leading to additional rejection drop.

No description available.

No description available.

The neuroprotective effects of AF4, a flavonoid-enriched extract derived from the peel of Northern Spy apples (containing quercetin-3-O-glucoside, quercetin-3-O-galactoside, quercetin-3-O-rhamnoside, quercetin-3-O-rutinoside, epicatechin, and cyanidin-3-O-galactoside) were examined by assessing neuronal loss and motor impairment resulting from hypoxic-ischemic (HI) brain injury in adult C57BL/6 mice. Relative to vehicle treatment (water, 10mL/kg/day), oral administration of AF4 (50 mg/kg/day) for 3 days reduces HI-induced neuronal loss in the striatum and hippocampus, motor impairments, and reduces the ability of LPS to stimulate the production of TNF-alpha in whole blood. Pretreatment with AF4 (1 ug/mL) decreased the death of mouse primary cortical neurons subjected to oxygen glucose deprivation (12 hours) in comparison to vehicle (DMSO) or the same concentration of quercetin or its metabolites. Taken together these findings indicate that AF4 reduces HI-induced brain injury and motor deficits by increasing the resistance of vulnerable neurons to ischemic cell death and decreasing the production of inflammatory cytokines.

The anthracycline quinone, doxorubicin (Adriamycin) is an antineoplastic agent that has substantial therapeutic activity against a broad variety of human cancers. Unfortunately, the use of this agent is limited by its cardiac toxicity, which is associated with free radical formation leading to apoptotic cell death. The goal of this work is to improve our understanding about doxorubicin induced cardiomyopathy and to identify compounds to limit doxorubicin induced cardiomyopathy. The knowledge gained here will have a generalized impact on all cardiac diseases involving oxidative stress and apoptosis. We show that doxorubicin induced apoptosis in primary neonatal rat cardiomyocytes can be attenuated by progesterone (PG). The anti-apoptotic action of PG was blocked by a progesterone receptor antagonist, Mifepristone (MF), indicating a progesterone receptor dependent pathyway. Affymetrix gene analyses found that PG treated cardiomyocytes increased the expression of 180 genes. Among the genes upregulated is NAD(P)H: Quinone Oxidoreductase-1 (NQO1) gene. NQO1 is a flavo-enzyme that can catalyze a two-electron reduction of Dox to a more stable hydroquinone, thereby acting as a defense mechanism against oxidative stress. The induction of NQO1 mRNA and NQO1 activity in cardiomyocytes was observed in a dose and time-dependent manner with PG treatment and was blocked by MF. Induction of NQO1 by b-naphoflavone, an inducer of NQO1, resulted in a decrease in caspase-3 activity. However, inhibition of NQO1 by dicoumarol did not attenuate the cytoprotective effect of PG. This data indicates that although induction of NQO1 can decrease Dox induced apoptosis, this is not the primary mechanism of cytoprotection induced by PG. Microarray analyses revealed that PG induced an increase of Bcl-XL mRNA. Inhibiting the expression of Bcl-XL using siRNA reduced the anti-apoptotic effect of PG, suggesting that Bcl-XL is a key player in PG induced cytoprotection. Western blot analyses indicated that PG induced the expression of Bcl-XL in a dose and time dependent manner consistent with the protective effect of PG. Induction of Bcl-XL by PG was blocked by cyclohexamide, but was not blocked by Actinomycin D indicating that a transcriptionally independent mechanism is responsible for the induction of Bcl-XL by PG. The activity of a bcl-x 3'UTR reporter was induced by PG and blocked by MF. These data suggest that PG may induce stabilization of the Bcl-X mRNA. We further explored the mechanism of PG induced Bcl-XL gene expression by comparing the effect of PG to two other steroids: corticosterone (CT) and retinoic acid (RA). Both CT and RA attenuate Dox induced apoptosis in cardiomyocytes. CT, but not RA or PG induced the activity of a GRE reporter plasmid. Analysis of the 5' region of the Bcl-XL promoter indicated that RA and CT, but not PG induced the activity of the 0.9kb region of the Bcl-XL promoter. The induction of the 0.9kb reporter plasmid by CT was glucocorticoid receptor dependent, since it was inhibited by MF. The Bcl-XL promoter does not contain any glucocorticoid or retinoid response elements, but does have AP-1 and NFkB response elements. CT, but not RA or PG induced the activity of an AP-1 reporter plasmid. RA, but not CT or PG induced the activity of an NFkB reporter plasmid. The induction of the 0.9kb Bcl-XL reporter plasmid by CT was blocked by expression of a dominant negative c-jun, TAM67 as well SB202190 indicating a nongenomic effect of CT in activating the Bcl-XL promoter through a p38 MAPK mediated AP-1 mechanism. Therefore although all three types of nuclear receptor ligands induce bcl-xL expression, the effect of CT is mediated by transcriptional activation by AP-1 signaling while NF-kB transcription factor appears to be involved in RA indced bcl-xL transcription.