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Biomedical subjects

D B Herrmann

Publications and source records attributed to D B Herrmann.

26 records · Page 2Linked to original sources

Changes in cellular lipid synthesis of normal and neoplastic cells during cytolysis induced by alkyl lysophospholipid analogues.

Susceptibility of eight different cell types of murine or human origins to alkyl lysophospholipid analogue (ALP)-induced cytolysis correlated well with a selective, dose-dependent inhibition of radiolabeled oleic acid incorporation into phosphatidylcholine (PC) and a concomitant stimulation of incorporation into neutral lipids (NL), mainly triacylglycerols. In resistant cells (murine macrophages, L929S, K562, and rMeth A) a counts per minute NL/counts per minute PC ratio of 0.8-1.0 was observed with 30 micrograms ALP/ml; in sensitive tumor targets (Meth A, HL60, YAC, and ABLS-8.1) values greater than 2.7 were found with 5-10 micrograms ALP/ml. Changes in lipid metabolism preceded cytolysis in Meth A fibrosarcoma cells. In degradation experiments the percentage of total lipid radioactivity in PC was reduced after 24 hours to 47% compared to that in controls in sensitive Meth A with 10 micrograms ALP/ml. The macrophage-PC was unaffected at the same concentration. Sensitivity to ALP was independent of cell proliferation. Resistance was not restricted to normal cells and was inducible in Meth A (and rMeth A).

Animals↗

Preparative continuous separation of biological particles by means of free-flow magnetophoresis in a free-flow electrophoresis chamber.

For sorting, cells or cellular components can specifically be labeled by antibody-coated magnetic beads. We have developed a device for continuous magnetic sorting based on the flow-chamber of a free-flow electrophoresis system. Magnetically labeled particles are injected into a given continuously flowing chamber buffer and pass an inhomogeneous magnetic field, configurated perpendicular to the flow direction. According to its magnetic moment, the magnetic material is deviated into the direction of the magnetic forces, while nonmagnetic material passes the field without interaction. The magnetic forces can be changed with the electrical current of the solenoids producing the magnetic field. As in the free-flow electrophoresis system, the particle fractions are collected in different vials. On-line control of the experiments can be performed by an optical scanning system. Experiments with model particles achieved a sorting purity of more than 99% at a rate of up to 5 X 10(8) particles per hour. In experiments with blood cells, a high enrichment of either B-or-T-lymphocytes was obtained. In contrast to free-flow electrophoresis, there is no limitation, in principle, regarding the type of chamber buffer to be used. This allows an optimal adaptation of the buffer conditions to the requirements of vital sorting. The preliminary results so far confirm this conclusion.

B-Lymphocytes↗

Antileishmanial activity of the ether phospholipid ilmofosine.

The ether phospholipid ilmofosine (BM 41.440) was active in vitro against amastigotes of Leishmania donovani and an antimony-resistant line of L. infantum in mouse peritoneal macrophages with ED50 values of 3.7 microM and 3.5 microM respectively. Ilmofosine was also active against L. donovani in BALB/c mice following oral and subcutaneous dosing, with an ED50 value of 10.5 mg/kg x 5 by the oral route.

Administration, Oral↗