Metallothioneins (MT) are the widespread proteins in animal world. These proteins are characterized by the great invariability of their structure. While isolated from the different organs of different animals they only slightly differ in the aminoacid composition from one another. Studies on the structure and biological functions of MT have identified four major isoforms (MT-I, -II, -III and ?IV) in mammals. Both MT-I and MT-II genes are expressed in various organs and they are inducible by a variety of metals, hormones, cytokines and xenobiotics. MT-III is expressed only in brain and no specific environmental regulatores have been identified. MT-IV is only expressed in differentiating cells of stratified squamous epithelia.
Zinc is required for multiple cellular tasks, and especially the immune system depends on a sufficient availability of this essential trace element. During the last decades, many studies attempted to affect the outcome of various diseases by zinc supplementation. These efforts either aimed at supporting immunity by zinc administration or at correcting a loss of zinc secondary to the disease to restore the zinc-dependent functions of the immune system. This review aims to summarize the respective findings and to discuss possible molecular mechanisms by which zinc could influence viral, bacterial, and parasitic infections, autoimmune diseases, and the response to vaccination. Zinc supplementation in diseases such as diarrhea, chronic hepatitis C, shigellosis, leprosy, tuberculosis, pneumonia, acute lower respiratory infection, and leishmaniasis seems beneficial. In contrast, the results for the common cold and malaria are still not conclusive, and zinc was ineffective in most vaccination and rheumatoid arthritis studies. For AIDS and type 1 diabetes, zinc supplementation may even be a risk factor for increased mortality or deterioration of the glucose metabolism, respectively. In these cases, zinc supplementation should be used with care and limited to clearly zinc-deficient individuals.
The Zn and Pb concentration was determined in 45 samples of bull semen from three Artificial Insemination Stations (A,B,C) differing in degree of environmental pollution. Bull semen was diluted with Biociphos-Plus to such an extent as to obtain 16 million sperm cells in an insemination dose. The research aimed at assessing the correlation between zinc, lead and other parameters influencing the semiological assessment of bull semen. The content of zinc and lead was determined with the use of the flame method and an absorption spectrophotometer (AAS). Positive, statistically significant correlations between zinc concentration and semen motility were observed in station A at r = 0,61 and station C at r = 0,614. In station B these correspondences were not statistically confirmed. Positive correlation at r = 0,583 was observed in case of zinc and the ejaculate volume only in station B. No statistically significant correlation was observed between lead concentration and the analyzed parameters.
The Domiaza is a fragment of the Oder river estuary situated north of Szczecin. This area is exposed to complex hydrological processes and strong anthropogenic pressure. Key physical and chemical parameters of the Domiaza sediments (fraction < 2mm), e.g., dry residue (Ds), ignition loss (Iz), CaCO3 and organic carbon content, show high coefficients of variation (over 60%). Similar variation is typical of the heavy metal concentrations (Cu, Zn, Pb, Co, Cd and Hg) and the organic carbon content in the fraction smaller than 0.20 mm. The spatial distribution of the examined parameters in the Domiaza sediments results from the dynamics of this environment, especially the heavy watercraft traffic and the continuous dredging of the Szczecin-Swinoujscie water lane. Concentrations of Cd, Cu, Zn, Pb and Co found in the Domiaza sediments are higher than those found in the geochemical background of Poland, while concentrations of mercury are comparable. Moreover, the concentrations of Cu, Zn, Pb and Cd found in the Domiaza sediments are higher than the average concentrations of these metals in adjacent areas (Oder River, Dabie Lake, Szczecin Lagoon), but the concentrations of Hg and Co are comparable or lower depending on the area of reference. A survey of heavy metals concentrations conducted in 1999 detected higher than average concentrations of Cu, Zn, Pb, and particularly Co (twice) and Hg (over thirty times), and lower concentrations of Cd in comparison with the average levels of 1996. The reason for these differences was the selective inflow of heavy metals to the Domiaza area after the disastrous flood of 1997.
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