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81.
Carl L. Keen Bo Lönnerdal Theodore N. Stein Lucille S. Hurley 《Biological trace element research》1980,2(3):221-227
The presence of superoxide dismutase in bovine and human milk was investigated by ultrafiltration, gel filtration, and isoelectric
focusing. Conclusive evidence for the presence of this enzyme in both milks is presented. The molecular weight of the enzyme
was estimated by gel filtration on Sephadex G-100 to be 30,000, which is consistent with reported values for the copper, zinc
form of superoxide dismutase. In addition, enzyme activity was inhibited by cyanide, thus eliminating the possibility that
the enzyme was present in the manganese form. Several isoenzymes were detected by isoelectric focusing in polyacrylamide gel,
and the isoenzyme pattern in bovine milk was the same as that found for bovine plasma, suggesting that milk superoxide dismutase
originates from plasma. It may be that the presence of copper, zinc superoxide dismutase in milk is important for the maintenance
of its oxidative stability. 相似文献
82.
Activities of Phosphorylase, glyceraldehyde-3 -phosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase and succinate
dehydrogenase in the rat endometrial tissue are significantly inhibited by an intrauterine copper device, while it stimulated
glucose-6-phosphate dehydrogenase activity. The copper device decreased the lactate/pyruvate ratio in the tissue; pyruvate
utilizationin vitro by the rat endometrium is also blocked by copper. These findings suggested that the normal carbohydrate metabolism of the
tissue may be affected in presence of copper, thus resulting in a change of the endometrial function, which may be one of
the factors responsible for the contraceptive and pharmacological action of an intrauterine copper device. 相似文献
83.
Andrzej J. Żelazowski Jadwiga A. Szymańska Czesklaw S. Cierniewski 《Chemico-biological interactions》1980,33(1):115-125
Two homogenous fractions of hepatic metallothioneins ((Cd,Zn) MT-1 and (Cd,Zn) MT-2) and renal metal binding proteins ((Bi,Cu) BP-1 and (Bi,Cu) BP-2) were isolated from rats exposed to heavy metals and specific antisera to them were produced in rabbits.These antisera were tested by immunodiffusion and immunoelectrophoresis for their ability to bind different fractions of hepatic Cd,Zn -metallothionein and renal (Bi,Cu)-, (Hg,Cu)- and (Cd,Cu)-binding proteins. It was found that anti (Bi,Cu) BP antisera did not cross-react with hepatic (Cd,Zn) MT-1 and (Cd,Zn) MT-2. Strong immunological cross-reactions were detected between anti (Bi,Cu) BP antisera and individual forms of (Cd,Cu)-, (Hg,Cu)- and (Bi,Cu)-binding proteins isolated from rat kidneys. 相似文献
84.
Washed or growing E. coli cells are killed by epinephrine, norepinephrine or dopamine in the presence of non lethal concentrations of Cu(II). Killing is enhanced by anoxia and by sublethal Concentrations of H2O1. The rate of killing is proportional to the rate of catecholamine oxidation. The copper epinephrine complex binds to E. coli cells, induces membrane damage and depletion of the cellular ATP pool. The cells may be partially protected by SOD or catalase but not by OH radical scavengers. Addition of H2O2 to cells which were sensitized by preincubation with the epinephrine-copper complex, causes rapid killing and DNA degradation. Sensitized cells are not protected by BSA. 相似文献
85.
A. M. Rofe J. C. Philcox D. R. Haynes M. W. Whitehouse P. Coyle 《Biological trace element research》1992,34(3):237-248
The early changes in hepatic metallothionein (MT) and plasma zinc (Zn), copper (Cu), and iron (Fe) were investigated during
the induction of adjuvant (AJ) arthritis in rats in conjunction with cyclosporin (CSA) treatment. Plasma Zn decreased after
AJ injection (60% of control values at 8 h), and this was associated with a 4.5-fold increase in hepatic MT at 8 h. Plasma
Zn was lowest at 16 h (40% of control), whereas hepatic MT concentrations increased to a maximum of 20-fold at 16 h. Changes
in plasma Fe paralleled those of Zn, whereas plasma Cu levels were increased. Plasma metal and hepatic MT concentrations returned
toward normal from d 1–7. At d 14, when marked paw swelling was apparent, hepatic MT and plasma Cu were again increased and
plasma Zn decreased.
Administration of CsA decreased MT induction in rats injected with AJ and also caused a marked recovery in plasma Zn and Fe
levels. These changes were small but significant even in the early stages (up to 24 h) after AJ injection and were followed
by a sustained improvement in all parameters, corresponding to the nonappearance of clinical arthropathy in CsA-treated rats.
TNF-α and IL-6 production by peritoneal macrophages isolated from AJ-injected rats was significantly decreased by CsA treatment
at d 7 and 14. The inhibition of hepatic MT induction during acute and chronic inflammation by cyclosporin emphasizes the
role of the immune system in altered metal homeostasis in inflammation. 相似文献
86.
Thyroid hormones are involved in copper and zinc distribution in rat tissues. We examined the influence of thyroparathyroidectomy
(TPTY) and of a replacement therapy by T4 on Cu and Zn organ distribution. MT levels were also measured both in basal conditions
and after induction by cadmium. The results confirm that a lack of T4 modified Cu and Zn in serum and tissues. In serum, TPTY
increased Cu (+15%) and ceruloplasmin (+18%), and decreased Zn (−18%). In tissues, Cu was altered in liver (+13%), kidney
(−24%), heart (−16%) duodenum (−18%), and Zn in liver (+25%) and kidney (−10%). The soluble fractions (100,000 g supernatant)
were mainly affected in liver and kidney, and the subcellular fractions in heart and duodenum. MT levels were modified in
basal conditions only in liver (+57%) and kidney (−36%). T4 administration partially prevented the effect of TPTY on both
elements and MT concentrations. Therefore, no evidence is provided for a direct role of T4 in the metabolism of MT in a way
comparable to the effects of glucocorticoids. However, MT could mediate the consequences of TPTY on metal distribution in
certain organs, such as liver and kidney. 相似文献
87.
88.
This paper describes a joint study of the structure and nonlinear optical properties of vacuum evaporated thin films of copper phthalocyanine (CuPc for brevity). Film thickness ranges from 50 to 500 nm. The anisotropic paramagnetic resonance of Cu++ ions reveals that the Pc rings lie almost parallel to the substrate plane with however a large angular distribution (30° FWHM). Third harmonic optical generation measurements performed at 1.064 m and 1.907 m fundamental wavelengths give respectively an average value of the cubic susceptibility (3)(-3,)=(4±0.4)·10–12 e.s.u. and (2.1+-0.2) · 10-12 These values, although significantly higher than for a common ionic crystal, are about one order of magnitude lower than in conjugated 1-D systems, which shows that the 2-D -electron delocalization is less profitable than the 1-D one. Besides third harmonic, we have also observed second harmonic generation. Its polarization dependence is characteristic of a quadratic susceptibility enhanced in one direction, almost perpendicular to the substrate, withd
eff comprised between 30 and 60 · 10-9 e.s.u. The possible origins ofd
eff are discussed. 相似文献
89.
Seasonal variation in copper and zinc concentrations in three talitrid amphipods (Crustacea) 总被引:1,自引:1,他引:0
Cu and Zn concentrations were determined for three talitrid amphipods, Orchestia gammarellus (Pallas), O. mediterranea Costa and Talitrus saltator (Montagu), collected at two-monthly intervals in 1987 from sites on Great Cumbrae Island, Firth of Clyde, Scotland. To account for size effects, log transformed Cu and Zn concentrations were regressed against log dry weight for each bimonthly sample of each species, and compared by analysis of covariance. Copper concentrations in O. gammarellus were significantly raised in March 1987, and lowered in November 1987. Copper concentrations in O. mediterranea and T. saltator were significantly lowered in November 1987. Cu concentrations differed interspecifically in the order O. gammarellus > O. mediterranea > T. saltator. There was no significant intraspecific seasonal variation in zinc concentration in any of the three species. Zn concentrations differed interspecifically in the order T. saltator > O. gammarellus > O. mediterranea. 相似文献