Biomedical subjects

M R Müller

Publications and source records attributed to M R Müller.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Influence of centrifugal blood pumps on the elasticity of erythrocytes.

The influence of centrifugal blood pumps on the elasticity of erythrocytes was tested in an in vitro set-up. Fresh bovine blood was pumped by vaneless and impeller blood pumps with low and high hemolytic potential (1L priming volume, flow 5 L/min versus 150 mmHg, pumping time 6 hours). The elasticity of the red blood cells was measured by laser diffraction. Starting with an elasticity of 238 +/- 39, the overall change during 6 hours was 12 +/- 38 compared to a change of the control value of -13 +/- -58. Even a pump with very high hemolytic potential (Hemolysis index 21.9) did not cause relevant changes of elasticity. It is concluded that 1) elasticity is not a useful parameter to use in the evaluation of centrifugal pumps, and 2) the mechanical trauma caused by centrifugal pumps produces no relevant permanent alteration of the elastic properties of red blood cells, at least under in-vitro conditions.

Animals↗

PubMedDate not supplied

Influence of a new relapse treatment for acute myeloid leukemia (AML) on in vitro granulopoiesis.

Twelve AML patients in relapse were treated with cytosine arabinoside (Ara-C), VP 16-213, vincristine, and vinblastine (A-triple-V). For bone marrow (BM) evaluation, in vitro granulopoiesis by agar and liquid cultures was investigated. In 15 treatments, 12 complete remissions (CR) were observed. Three patients, treated with 2 A-triple-V cycles achieved CR twice. One to four months after treatment normal colony formation and cell differentiation was found in remission patients. Evidence of sustained recovery was obtained in sequential studies of BM cultures of patients in CR. These results indicate that-A-triple-V treatment does not irreversibly deplete normal myeloid progenitor cell population.

Adult↗

PubMedDate not supplied

Chemosensitisation of alkylating agents by pentoxifylline, O6-benzylguanine and ethacrynic acid in haematological malignancies.

The effects of resistance modifiers (RM) on the cytotoxicity of mafosfamide (MAF), bis-chloroethylnitrosourea (BCNU) and dacarbazine (DTIC) were evaluated by the MTT colorimetric assay in isolated lymphocytes and blast cells derived from patients with chronic lymphatic leukaemia (CLL; n = 28) and acute myeloid leukaemia (AML; n = 30), or from healthy donors (n = 19). Pentoxifylline (PTX) has been shown to restore sensitivity to alkylating drugs by interfering with DNA repair. PTX (10 microM) significantly sensitised leukaemic blasts to the cytotoxic effect of MAF. In 8 out of 30 AML samples, sensitisation ratios (SRs; i.e. cytotoxic drug ID50s in the presence or absence of RM) for MAF in the presence of PTX were > 2 ranging up to 4.2. Inhibition of the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT) by O6-benzylguanine (O6-BG; 50 microM) enhanced the cytotoxicity of DTIC in CLL lymphocytes. SRs > 2 for DTIC in the presence of O6-BG were observed in 7 out of 28 CLL specimens. Sensitisation was generally greater in the more chemo-resistant specimens. Ethacrynic acid (EA; 1 microM), an inhibitor of glutathione-S-transferases (GST), failed to influence the cytotoxicity of alkylating agents in any cell type. Also, all examined RMs did not sensitive leukaemic cells to the cytotoxic effect of BCNU. The data show significant chemosensitisation of leukaemic cells to alkylating agents by PTX and O6-BG, indicating a potential clinical use of these substances as RM in patients.

Acute Disease↗