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1

Inhibition by fatty acids of the cholesterol side-chain cleavage in the course of progesterone biosynthesis in the mitochondrial fraction of human term placenta

100%

Tiałowska B., Klimek J., Żelewski L.

Acta Biochimica Polonica

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1980

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vol. 27

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issue 3-4

257-264

2

Progesterone biosynthesis supported by fatty acid oxidation in the mitochondrial fraction of human term placenta

100%

Tiałowska B., Klimek J., Żelewski L.

Acta Biochimica Polonica

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1983

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vol. 30

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issue 1

11-21

3

AMP-deaminase from hen stomach smooth muscle - physico-chemical properties of the enzyme.

88%

Swieca A., Rybakowska I., Koryziak A., Klimek J., Kaletha K.

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vol. 51

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issue 1

213-218

EN

AMP-deaminase from hen stomach smooth muscle was isolated and physico-chemical properties of the purified enzyme were investigated. The enzyme had an activity optimum at pH 6.5, and poorly deaminated the substrate analogues tested. At optimum pH (6.5), in the absence of regulatory ligands (control conditions), the enzyme manifested hyperbolic substrate-saturation kinetics with half-saturation constant (S0.5) of about 4.5 mM. Additions of adenine nucleotide effectors (ATP, ADP) activated the enzyme strongly at all the concentrations tested, diminishing significantly the value of S0.5 constant. In contrast, the regulatory effect of orthophosphate was variable, and depended on the orthophosphate concentration used. The molecular mass of the enzyme subunit determined in SDS/PAG electrophoresis was about of 37 kDa. The obtained results suggest that in different types of hen muscle, similarly as in humans and rats, expression of AMP-deaminase is under the control of independent genes.

4

Partial characterization of human choriocarcinoma cell line JAR cells in regard to oxidative stress.

64%

Hallmann A., Klimek J., Masaoka M., Kamiński M., Kędzior J., Majczak A., Niemczyk E., Woźniak M., Trzonkowski P., Wakabayashi T.

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vol. 51

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issue 4

1023-1038

EN

Characterization of free radical-induced cell injury processes of placenta cells is of vital importance for clinical medicine for the maintenance of intrauterine fetal life. The present study has analyzed cell injury processes in cells of the choriocarcinoma cell line JAR treated with menadione, an anticancer drug, and Hg2O2 in comparison to osteosarcoma 143B cells using electron microscopic and flow cytometric techniques. Flow cytometry on JAR cells exposed to 100 μM menadione and double-stained with Annexin V and propidium iodide (PI) detected apoptotic cells reaching the maximum after 4 h of incubation with a rapid decrease thereafter. Viable cells became decreased to 46% of the control after 2 h of incubation, reaching 5% after 4 h. Cells stainable with both Annexin V and PI began to increase distinctly after 2 h of incubation, reaching 55% after 4 h. Electron microscopy showed that cells stainable with both dyes specified above had condensed nuclei and swollen cytoplasm, suggesting that they were undergoing a switch of the cell death mode from apoptosis to necrosis. On the other hand, 90% of 143B cells remained intact after 4 h of menadione treatment although the intracellular levels of superoxide were always higher than those of JAR cells treated with the drug. In contrast, JAR cells were more resistant than 143B cells to H2O2-induced cytotoxicity. These results may suggest that cytotoxicity of menadione cannot be explained simply by oxygen free radicals generated from the drug. The resistance of JAR cells to oxygen free radical-induced cytotoxicity may be advantageous for intrauterine fetal life.

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4 Acta Biochimica Polonica

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2 Tiałowska B.

2 Żelewski L.

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1 Kamiński M.

1 Koryziak A.

1 Kędzior J.

1 Majczak A.

1 Masaoka M.

1 Niemczyk E.

1 Rybakowska I.

1 Swieca A.

1 Trzonkowski P.

1 Wakabayashi T.

1 Woźniak M.

Inhibition by fatty acids of the cholesterol side-chain cleavage in the course of progesterone biosynthesis in the mitochondrial fraction of human term placenta

Progesterone biosynthesis supported by fatty acid oxidation in the mitochondrial fraction of human term placenta

AMP-deaminase from hen stomach smooth muscle - physico-chemical properties of the enzyme.

Partial characterization of human choriocarcinoma cell line JAR cells in regard to oxidative stress.