Search results for "metallothionein"
showing 10 items of 60 documents
Zinc and inflammatory/immune response in aging
2007
Life-long antigenic burden determines a condition of chronic inflammation, with increased lymphocyte activation and proinflammatory cytokine production. A large number of studies have documented changes in zinc metabolism in experimental animal models of acute and chronic inflammation and in human chronic inflammatory conditions. In particular, modification of zinc plasma concentration, as well as intracellular disturbance of antioxidant intracellular pathways, has been found in aging and in some age-related diseases. Zinc deficiency is diffused in aged individuals in order to avoid meat and other high zinc content foods due to fear of cholesterol. Rather, they increase the consumption of r…
Metallothionein overexpression and its prognostic relevance in intrahepatic cholangiocarcinoma and extrahepatic hilar cholangiocarcinoma (Klatskin tu…
2009
Metallothionein is a group of small molecular weight cysteine-rich proteins with a broad variety of functions. Metallothionein has been shown to regulate apoptosis and proliferation. Overexpression of metallothionein frequently occurs in human tumors and is related to prognosis as well as therapy response. However, metallothionein expression and its clinical relevance in cholangiocarcinoma have not been investigated. The present study aimed to analyze metallothionein over-expression and its possible prognostic impact in intrahepatic cholangiocarcinoma and hilar extrahepatic cholangiocarcinoma (Klatskin tumors). We investigated the relationship of immunohistochemically demonstrated metalloth…
Effect of cadmium exposure on zinc levels in the brine shrimp Artemia parthenogenetica
1999
Zinc and cadmium have been reported as metabolic antagonists, such that high zinc intake afford animals some protection against the potentially toxic effects of cadmium exposure. There is considerable evidence to support a role of metallothioneins (MTs) in regulating or controlling the intracellular availability of essential metals and the non-essential metal. The effect of 24-h cadmium pre-exposure (10 mg Cd/l) on zinc concentrations in the brine shrimp Artemia parthenogenetica exposed to zinc (5 mg Zn/l) was studied. The zinc content of shrimps was not altered by cadmium. The homeostatic mechanism for zinc regulation appears not to be disturbed by cadmium exposure in shrimps kept in natur…
Quantification of cadmium-induced metallothionein in crustaceans by the silver-saturation method
1995
Metallothionein (MT) has been proposed as a specific biochemical probe for metal exposure of aquatic organisms. It is recognized that its usefulness as a monitoring tool depends on the full understanding of its function and on the possibility of measuring its concentration in tissues. Therefore the study of MT in crustaceans is interesting from two different points of view: the need to understand mechanisms associated with the toxicology of metals, and the potential use of this protein for monitoring metal-contamined environments. Several methods have been developed for quantitative measurements of MT in biological samples. Immunochemical and electrochemical procedures are reliable techniqu…
Are zinc-bound metallothionein isoforms (I+II and III) involved in impaired thymulin production and thymic involution during ageing?
2004
Abstract Background With advancing age, thymic efficiency shows progressive decline due to thymic involution allowing impaired cell-mediated immunity and the appearance of age-related diseases. The intrinsic cause of thymic involution is still undefined. Chronic inflammation and high glucocorticoids (GCs) may be involved. However, transgenic mice, with increased GC sensitivity and over expression of GC receptors, display delayed age-associated thymic involution. This fact suggests that other substances may affect thymic involution. Among them, both isoforms of metallothioneins (MTs) I+II and III are the major candidates because their increments leads to organ atrophy in constant stress and …
Metalotioneiny i motywy policysteinylowe : oddziaływanie z jonami metali
2018
Many of biochemical paths and processes require some metal ions to occur. There are also known the negative effects of the presence of metal ions in the organism. The both sides of metal ions interactions on the living organism require specific regulations and cannot be left without supervision and control of the organism itself. One of the strategy to keep the control on metal ions are cystein-rich proteins that play crucial role in detoxication of metal ions that are dangerous for human organism as well as they help to maintain homeostasis of essential metal ions. Matallothioneins are one of the well known, but still not fully understood, cysteine- rich proteins. They are small proteins b…
Concentrations of metallothionein in the bivalve molluscsAnodonta spp.andUnio spp.from Latvian lakes with different anthropogenic pressure
2013
Concentrations of metallothioneins (MT) were analysed in bivalve molluscs Anodonta spp. and Unio spp. from 6 lakes and watercourses of Latvia with different anthropogenic pressure. The aim of the study was to find the relationship between MT in molluscs and concentrations of heavy metals in sediments. Unio spp. and Anodonta spp. showed no significant differences in the concentrations of MT. High concentrations of heavy metals (Cd, Pb, Hg, Cu, Zn) were detected in the deepest parts of polluted water bodies, however their concentrations significantly decreased in near shore sediments inhabited by molluscs. Only Zn tends to accumulate in the molluscs, reaching 2-7 times higher concentrations i…
Characterization and transcription studies of a phytochelatin synthase gene from the solitary tunicate Ciona intestinalis exposed to cadmium.
2014
The major thiol-containing molecules involved in controlling the level of intracellular ROS in eukaryotes, acting as a nonenzymatic detoxification system, are metallothioneins (MTs), glutathione (GSH) and phytochelatins (PCs). Both MTs and GSH are well-known in the animal kingdom. PC was considered a prerogative of the plant kingdom but, in 2001, a phytochelatin synthase (PCS) gene was described in the nematode Caenorhabditis elegans; additional genes encoding this enzyme were later described in the earthworm Eisenia fetida and in the parasitic nematode Schistosoma mansoni but scanty data are available, up to now, for Deuterostomes. Here, we describe the molecular characteristics and transc…
Immunohistochemical evaluation of metallothionein in palatal mucosal cells of mice treated with 4NQO
2006
Objective: Metallothionein (MT) may play a preventive role in various carcinogenic process. 4NQO is an alkaline compound and potent mutagen that causes the formation of DNA adducts. The purpose of this study was to evaluate the immunoexpression of MT in palatal cells of mice submitted to the carcinogen 4NQO. Study design: C57BL/6 mice received applications of 4NQO to palate for periods of 8, 16, 20 and 24 weeks (experimental group). A control group received only applications of propylene glycol for the same periods. Subsequently animals of experimental and control groups were sacrificed and the palate was histologically analysed and MT immunohistochemistry performed. Results: Although morph…
Metallothionein genes in the sea urchin Paracentrotus lividus
2014
Metallothioneins (MTs) constitute a heterogeneous superfamily of cysteine rich proteins, which coordinate divalent (Zn2+, Cd2+) or monovalent (Cu+) metal ions. Several functions have been proposed for these peptides, ranging from toxic metal protection to physiological metal homeostasis, free radical scavenging, oxidative stress protection, antiapoptotic defense, control of the redox status of the cell and also a role during development. Regarding the MT system in vertebrates’ nearest kin, little information is available at present. Recently MTs were also characterized in cephalochordates. Hence in order to shed some light on MT origin and functional differentiation through evolution, we st…