Alena MICHALSKA

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We report the generation of transgenic mice deficient in the metallothionein MT-I and MT-II genes. The mutations were introduced into embryonic stem cells by homologous recombination. Chimeric mice resulting from the targeted embryonic stem cells transmitted the disrupted alleles through their germ line. Homozygous animals were born alive and appeared(More)
Metallothionein (MT) has several putative roles in metal detoxification, in Zn and Cu homeostasis, in scavenging free radicals, and in the acute phase response. Mice of mixed 129/Ola and C57BL/6J background with targeted disruption of MT-I and MT-II genes are more sensitive to toxic metals and oxidative stress. We noted that these animals were larger than(More)
Embryonic cells from transgenic mice with targeted disruption of metallothionein I and II genes expressed no detectable metallothionein either constitutively or after treatment with cadmium, in contrast to cultured cells that were wild type or heterozygous for the loss of the metallothionein genes. Metallothionein null cells were most sensitive to the(More)
Cadmium (Cd) is known to have a long biological half-life in the body, possibly due to its binding to metallothionein (MT). This study was designed to determine the role of MT in the tissue distribution and retention of Cd using MT-I and -II null (MT-null) mice. Mice were given 109CdCl(2) (15 mumol/kg, 25 microCi/kg, i.p.), and radioactivity was quantified(More)
In order to clarify a possible protective role of metallothionein (MT) in the development of streptozotocin (STZ)-caused insulin-dependent diabetes mellitus (IDDM) and its mechanisms, we studied whether MT is effective for protection against STZ-caused IDDM by utilizing MT-null (isoforms MT-I and II) transgenic mice. It was found that Zn pretreatment (I(More)
Pa vIas M., Alena Michalska, M. H unady: Diagnosis of Avian Tubercu/osis• -Mycobacteriosis by Rapid Agglutination. Acta vet. Brno, 62, 1993: 63-69. In contrast to the intradermal tuberculin test (ITT) the sensitivity and specificity of rapid agglutination eRA) using the M. avium serovar 2, 3 antigen increased at advanced stages of the infection. Only 47.7%(More)
Overexpression of metallothioneins (MTs) protects some cells against heavy metals, mutagens, anticancer agents, and reactive oxygen species. We have examined the effect of the loss of MT expression on the cytotoxicity of anticancer agents and mutagens using embryonic fibroblast cells from transgenic mice with targeted disruptions of MT I and II genes (MT(More)
Zinc pretreatment has been shown in vitro (rat myoblasts) to induce metallothionein (MT) and inhibit cadmium (Cd)-induced protooncogenes c-myc and c-jun mRNA levels. therefore, the purpose of this study was to determine whether the mRNA expression of the protooncogene c-jun as well as the tumor suppressor gene p53 is increased by Cd in the intact animal(More)
The action of endotoxin lipopolysaccharide (LPS) on hepatic Zn uptake was examined in mice lacking expression of metallothionein (MT)-1 and MT-II genes. Hepatic Zn concentrations, which in normal control mice increased by a mean 29% (MT elevated 20-fold) 16 h post-LPS exposure, did not increase in MT-null mice. Plasma Zn fell by 68% in controls and 32% in(More)
Metallothioneins (MTs) are low-molecular weight, cysteine-rich, metal-binding proteins. Pretreatment of animals with Zn increases tissue MT concentrations, and protects against Cd-induced toxicity. However, Zn treatment produces many effects in addition to increasing MT. Therefore, MT-I and -II knock-out (MT-null) mice were used to determine the roles of MT(More)