Benjamin Drewinko

Use of the cytocentrifuge in the diagnosis of meningeal leukemia

The cytocentrifuge provides a rapid and effective means of preparing cytologic preparations of diagnostic quality in patients with meningeal leukemia. Serial studies during intrathecal therapy are useful in determining the adequacy of therapy. The technique is most useful in detecting early CNS relapse as the CSF is monitored during CNS remission.

Effect of chemotherapy on the labelling index of myeloma cells

The labelling index, namely the percentage of bone marrow plasma cells incorporating tritiated thymidine after short in vitro exposures, was correlated with tumor mass reduction following chemotherapy in 37 patients with multiple myeloma. Tumor mass reduction was assessed from changes in myeloma protein production rate. Patients untreated or not responding to treatment had the lowest labelling index values. The median labelling index increased more than six‐fold when tumor mass was reduced by more than 50%. These findings support the concept that an increased fraction of myeloma cells proliferates during remission and justify clinical trials with cell cycle‐active drugs in selected patients with a high labelling index.

Effect of Donation Time on Platelet Concentrates and Fresh-Frozen Plasma. An in vitro Study

Abstract. To investigate the effect of donation time on the quality of blood components, we measured the platelet count and pH on platelet concentrates, and the factor V and VIII: C levels and fibrinopeptide A concentration on fresh‐frozen plasma by duration of donation time. Platelet concentrates and fresh‐frozen plasma were classified into three groups according to donation time: group 1, less than 10 min; group 2, 10–15 min, and group 3, longer than 15 min. Mean platelet counts of platelet concentrate were: group 1, 8.6±2.5 (in x 1010), group 2, 8.1±2.6, and group 3, 6.5±3.2 (p<0.05). The same pH was maintained in all three groups. The fibrinopeptide A concentrations in groups 1 and 2 were 24±53 and 169±64 ng/ml, respectively, while in group 3 all were >200 ng/ml, indicating correlation of a higher fibrinopeptide A level with longer donation time. Although a higher fibrinopeptide A level indicated a greater degree of thrombin generation, assays of factors V and VIII: C did not show decreased activity in groups 2 and 3.

Medroxyprogesterone acetate does not protect human bone marrow progenitor cells exposed to adriamycinin vitro

Progestins such as medroxyprogesterone acetate (MPA) have been used as part of combined chemotherapeutic and hormonal therapy to treat endocrine-related malignancies such as breast cancer and ovarian cancer (1, 2, 3). These studies reported that leucopenia was less severe in patients who received both progestins and cytytoxic drugs than in patients who received cytotoxic drugs only. This decreased myelosuppression in patients receiving progestins often allowed the administration of higher doses of myelosuppressive drugs. We investigated whether a progestin such as MPA would show a similar myeloprotective effect on human bone marrow progenitor cells exposed to Adriamycin in an in vitro system. We chose Adriamycin because (a) myelosuppression is one of its doselimiting toxicities, (b) it is active in vitro without prior bioactivation, and (c) it is a frequent component of the chemotherapeutic regimens for both breast cancer and ovarian cancer.

Responses of human bone marrow progenitor cells to fluoro-ara-AMP, homoharringtonine, and elliptinium

SummaryThe cytotoxicity of the investigational anticancer drugs fluoro-ara-AMP, homoharringtonine, and elliptinium on normal human granulocyte-macrophage colony-forming units in culture (GM-CFU) was investigated using a bilayer soft agar system. For each drug, the dose-dependent survival curve on a semilogarithmic plot formed a straight line. The Do were: 0.51 μg/ml (fluoro-ara-AMP), 0.004 μg/ml (homoharringtonine) and 0.026 μg/ml (elliptinium). The in vitro toxicity of drugs on bone marrow progenitor cells did not correlate with the relative myelosuppressive potency observed in vivo.

Role of culture conditions and exposure duration in determining sensitivity of human bone marrow progenitor cells to methotrexate

SummaryThe effect of drug concentration, exposure duration, and culture conditions on the cytotoxic activity of methotrexate (MTX) on normal granulocyte-macrophage colony-forming units in culture (GM-CFUC) was studied using a bilayer soft agar system with nucleoside-free medium. The degree of inhibition of colony formation depended on the type of serum supplementation. A 1 h or 2 h pulse treatment with 2×10-4 M (100 μg/ml) MTX failed to kill GM-CFUC, when the cells were subsequently plated in a system containing 15% undialyzed fetal bovine serum (FBS). For continuous exposure the observed LD50 of MTX in the agar system was higher than 10-4 M for 15% undialyzed FBS, 10-5 M for 15% dialyzed FBS plus 0.25% undialyzed FBS, 10-6 M for 15% dialyzed FBS, and 10-8 M for 15% undialyzed horse serum. The difference for dialyzed FBS versus horse serum can be explained by differences in nucleoside concentrations. The difference for dialyzed FBS versus horse serum may be secondary to an enhancer of MTX in horse serum. For studying MTX sensitivity of human tumor cells in vitro, we suggest testing conditions that lie within the dose survival curve of GM-CFUC.

Effect of thymidine on the toxicity and antitumor activity of cis-diamminedichloroplatinum (II).

SummaryThe effect of thymidine (TdR) on the preclinical toxicity of cis-diamminedichloroplatinum (II) (DDP) was investigated in the BDF1 mouse and the Sprague-Dawley rat. The effect of TdR on the antitumor activity of DDP was investigated using the ascites P388 murine leukemia model. TdR at 500 mg/kg consistently decreased the recovery of body weight after DDP treatment IP, but did not affect the lethal toxicity of DDP to non-tumor-bearing mice or those with the P388 murine leukemia. This effect was greatest when TdR was injected 30 min prior to DDP and at higher doses of DDP. A500-mg/kg dose of TdR did not affect the antitumor activity of DDP 5 mg/kg administered on days 1, 5, and 9. Treatment of rats with TdR 500 mg/kg according to various schedules of timing relative to a 5-mg/kg dose of DDP did not consistently affect the DDP-related loss in body weight or nephrotoxicity at day 3. Pretreatment of mice with TdR 1,500 mg/kg 30 min prior to DDP 5 mg/kg (every 4 daysx3) resulted in a slower recovery of body weight, which became more pronounced with increasing doses of DDP. Pretreatment of ascites P388-bearing mice with TdR 1,500 mg/kg increased the number of early deaths when mice were treated with DDP 5 mg/kg (days 1, 5, and 9). These data suggest that the cytotoxicity of DDP is increased by TdR only at higher doses of either drug, but that the antitumor activity against P388 murine leukemia is not affected.

The Radiation Response of a Long-term Culture of Human Lymphoid Cells

SummaryThe radiation response of a long-term culture of human immunoglobulin-producing lymphoid cells (T1 cells) studied by the colony-forming method, is remarkably similar to the response of other mammalian cell cultures. The relevant parameters are: n = 7–8; Dq = 175 rads and D0 = 85 rads. The cells also demonstrate the ability to repair x-ray damage when the total dose is delivered in two separate exposures. Repair results in the restitution of the shoulder region in dose-dependent survival curves. T1 cells, as an in vitro model for the radiation response of lymphoid cells, contradict the classical contention that immunocytes are extremely radiosensitive.