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101.
Wiseman DA Wells SM Wilham J Hubbard M Welker JE Black SM 《American journal of physiology. Cell physiology》2006,291(3):C555-C568
While nitric oxide (NO)-mediated biological interactions have been intensively studied, the underlying mechanisms of nitrosative stress with resulting pathology remain unclear. Previous studies have demonstrated that NO exposure increases free zinc ions (Zn2+) within cells. However, the resulting effects on endothelial cell survival have not been adequately resolved. Thus the purpose of this study was to investigate the role of altered zinc homeostasis on endothelial cell survival. Initially, we confirmed the previously observed significant increase in free Zn2+ with a subsequent induction of apoptosis in our pulmonary artery endothelial cells (PAECs) exposed to the NO donor N-[2-aminoethyl]-N-[2-hydroxy-2-nitrosohydrazino]-1,2-ethylenediamine. However, NO has many effects upon cell function and we wanted to specifically evaluate the effects mediated by zinc. To accomplish this we utilized the direct addition of zinc chloride (ZnCl2) to PAEC. We observed that Zn2+-exposed PAECs exhibited a dose-dependent increase in superoxide (O2·) generation that was localized to the mitochondria. Furthermore, we found Zn2+-exposed PAECs exhibited a significant reduction in mitochondrial membrane potential, loss of cardiolipin from the inner leaflet, caspase activation, and significant increases in TdT-mediated dUTP nick end labeling-positive cells. Furthermore, using an adenoviral construct for the overexpression of the Zn2+-binding protein, metallothionein-1 (MT-1), we found either MT-1 overexpression or coincubation with a Zn2+-selective chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylene-diamide, in PAECs significantly protected the mitochondria from both NO and Zn2+-mediated disruption and induction of apoptosis and cell death. In summary, our results indicate that a loss of Zn2+ homeostasis produces mitochondrial dysfunction, increased oxidative stress, and apoptotic cell death. We propose that regulation of Zn2+ levels may represent a potential therapeutic target for disease associated with both nitrosative and oxidative stress. reactive nitrogen species; apoptosis mitochondrial dysfunction 相似文献
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103.
The ability of a range of dietary flavonoids to inhibit low-density lipoprotein (LDL) oxidation in vitro was tested using a number of different methods to assess oxidative damage to LDL. Overall quercetin was the most effective inhibitor of oxidative damage to LDL in vitro. On this basis, a diet enriched with onions and black tea was selected for a dietary intervention study that compared the effect on the Cu2+ ion-stimulated lag-time of LDL oxidation ex vivo in healthy human subjects of a high flavonoid diet compared with a low flavonoid diet. No significant difference was found in the Cu2+ ion-stimulated lag-time of LDL oxidation ex vivo between the high flavonoid and low flavonoid dietary treatments (48 ± 1.6 min compared to 49 ± 2.1 min). 相似文献
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106.
Rowland I Wiseman H Sanders T Adlercreutz H Bowey E 《Biochemical Society transactions》1999,27(2):304-308
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108.
Clarke DB Lloyd AS Botting NP Oldfield MF Needs PW Wiseman H 《Analytical biochemistry》2002,309(1):158-172
A method has been developed for the analysis of phytoestrogens and their conjugates in human urine using liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Stable isotopically labeled [13C(3)]daidzein and [13C(3)]genistein were synthesized and used as internal standards for isotope dilution mass spectrometry. Free aglycons and intact glucuronide, sulfate, diglucuronide, disulfate, and mixed sulfoglucuronide conjugates of isoflavones and lignans were observed in naturally incurred urine samples. Sample pretreatment was not necessary, other than addition of internal standards and pH adjustment. Urine was injected directly onto the analytical column. The limits of detection were generally <50ng/ml, precision was generally <10% CV for conjugates. Total hydrolyzed daidzein and genistein were measured against quality assurance urine sample and were accurate to within 12%. The accuracy of conjugate measurement can not be ascertained, as no reference samples are available. The mean sum of daidzein and its conjugates was within 20% of the hydrolyzed value. Concentrations of the free aglycons of up to 22% of genistein and 18% of daidzein were observed. The average pattern was ca. 54% 7-glucuronide, 25% 4(')-glucuronide, 13% monosulfates, 7% free daidzein, 0.9% sulfoglucuronides, 0.4% diglucuronide, and <0.1% disulfate. Selective enzymatic deconjugation with glucuronidase and mixed glucuronidase/sulfatase were used to validate the accuracy of the quantitation of the intact daidzein conjugates. There were no apparent sex differences, or conditioning effects on the conjugation profile of isoflavones after chronic dosing. 相似文献
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110.
Inhibition of the proteolysis of rat erythrocyte membrane proteins by a synthetic inhibitor of calpain 总被引:4,自引:0,他引:4
S Mehdi M R Angelastro J S Wiseman P Bey 《Biochemical and biophysical research communications》1988,157(3):1117-1123
A synthetic inhibitor of calpain protects rat erythrocyte membrane-associated cytoskeletal proteins from proteolytic degradation (IC50 = 1 microM) which occurs when the cells are rendered permeable to Ca++. Leupeptin, a naturally occurring inhibitor of the enzyme, does not afford any protection at concentrations up to 100 microM. 相似文献