Biomedical subjects

J Bergmann

Publications and source records attributed to J Bergmann.

74 records · Page 5Linked to original sources

PubMedDate not supplied

Multidrug resistance of murine leukemia cells characterization and correlation with cytochrome P-450 dependent activities, cytosolic calcium and cell cycle state.

This paper reports studies on P388 leukemic cells sensitive and resistant to ADR and VCR. The P450 dependent enzyme system and the cytosolic calcium were estimated and are discussed in relation to MDR. It could be shown, in comparison to sensitive P388 cells, that the plasma membrane permeability for fluorescent dyes like rhodamine 123 and fura-2 and the biotransformation of xenobiotics are changed in resistant cells. Whereas the transport behaviour for the dyes is similarly induced in resistant cells independent of the drug which made the MDR, the P450 dependent enzyme activities are strongly increased in P388/ADR in comparison to the P388 and P388/VCR. The cell cycle analysis shows the same effect. Many more cells of P388/ADR are in the S-phase in comparison to P388 or P388/VCR. The LI is also increased in this direction. Therefore, it can be concluded that, depending on the kind of drug which made the MDR, different biochemical mechanisms are activated.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Multiple effects of antitumor alkyl-lysophospholipid analogs on the cytosolic free Ca2+ concentration in a normal and a breast cancer cell line.

Synthetic alkyl-lysophospholipids (ALP) are a new class of antitumor agents which interact with the cell membrane and the intracellular signal transduction at several sites. We studied the modulation of the intracellular calcium concentration ([Ca++]i) induced by two alkylglycerophosphocholines as well as hexadecylphosphocholine and hexadecylphosphoserine in a nontumorigenic and in a tumorigenic breast cell line. We found three distinct [Ca++]i-modulating effects: a transient increase, a decrease and a sustained increase. Their relative contribution to the observed response varies with different cell types, with the proliferation state, with the structure and with the concentration of the ALP analogs. The transient as well as the sustained increase in [Ca++]i depend mainly on extracellular Ca++; however, the Ca++ influx-inducing pathways might be different. The multiple [Ca++]i-increasing and decreasing effects induced by ALP analogs are discussed in relation to their influence on numerous Ca(++)-dependent effects, e.g. proliferation, differentiation, apoptosis and cytotoxicity.

Alkylation↗