Biomedical subjects

R L Fine

Publications and source records attributed to R L Fine.

61 records · Page 4Linked to original sources

PubMed1985

Formation of methotrexate polyglutamates in purified myeloid precursor cells from normal human bone marrow.

Immature myeloid precursor cells were preferentially selected from normal human bone marrow by using immune rosette techniques that employed monoclonal antibodies against mature granulocytes, monocytes, T and B lymphocytes, and erythroid precursors (Mo5, M3, OKT3, B1, and EP1, respectively). We examined the formation, retention, and cytotoxic effects of methotrexate (MTX) polyglutamates (MTX-PGs) in these purified myeloid precursor cells. After 1- and 24-h exposures to MTX, with thymidine and deoxyinosine as rescue, the intracellular MTX-PG profile was examined by high-pressure liquid chromatography. Efflux patterns of MTX-PGs were also studied after additional 1- and 24-h incubations in drug-free media. Cytotoxic effects of retained MTX-PGs on bone marrow myeloid precursors were examined by colony formation in drug-free semisolid agar. Normal myeloid precursor cells converted MTX to MTX-PGs in a concentration- and time-dependent manner, preferentially retaining MTX-PGs with three to five glutamyl moieties. At low concentrations of MTX (1 microM), MTX-PG formation was insufficient to maintain saturation of the target enzyme dihydrofolate reductase after removal of drug from the incubation medium, and there was no decrease in myeloid colony formation. At higher concentrations of MTX (10 microM), formation of higher molecular weight polyglutamates was sufficient to allow for 24-h saturation of intracellular binding capacity after removal of extracellular drug and resulted in a 35% reduction in the formation of colony-forming units in culture. Comparison of MTX metabolism in normal bone marrow cells and the MTX-sensitive HL-60 human leukemia cell line showed twofold greater PG formation by these tumor cells after 24-h exposure to 1 or 10 microM MTX, and a marked (greater than 30-fold) increase in cytotoxicity for the HL-60 cells as compared with normal myeloid precursors, suggesting that the MTX polyglutamation may be important to its selective antitumor action.

Bone Marrow↗

PubMed1985

A phase I and pharmacokinetic study of dihydro-5-azacytidine (NSC 264880).

5,6-Dihydro-5-azacytidine (DHAC; NSC 264880) is an analogue of 5-azacytidine that does not possess the hydrolytically unstable 5,6-imino bond of the parent compound. Thus, unlike 5-azacytidine, DHAC is stable in aqueous solution and may be administered by prolonged i.v. infusion, potentially avoiding acute toxicities associated with bolus administration of 5-azacytidine. In this study, patients with advanced cancer were treated with DHAC administered as a 24-h constant i.v. infusion every 28 days. Treatment began at a dose of 1 g/sq m and was escalated to the maximum-tolerated dose of 7 g/sq m, where the limiting toxicity was pleuritic chest pain. Other toxicities included nausea and vomiting, which were not limiting. There was no evidence for myelosuppression, nephrotoxicity, or hepatotoxicity. DHAC was measured in plasma, urine, and ascites by a sensitive and specific reverse-phase high-performance liquid chromatography assay capable of detecting 50 ng of drug per ml. Steady-state plasma levels were achieved with 8 h and ranged from 10.0 to 20.5 micrograms of DHAC per ml at the maximum-tolerated dose. Total-body clearance of 311 +/- 76 ml/min/sq m and postinfusion half-lives between 1 and 2 h were observed. Between 8 and 20% of the administered dose was excreted unchanged in urine. While ascites DHAC levels in a patient with ovarian cancer were comparable to plasma levels, postinfusion elimination was slower from this compartment than from plasma. No correlation was observed between DHAC plasma levels and duration or intensity of dose-limiting pleuritic chest pain. One patient with progressive Hodgkin's lymphoma demonstrated stabilization of disease for seven treatment cycles, and two patients with aggressive lymphoma demonstrated dramatic, although transient, disease responses. A dose of 7 g/sq m is recommended for Phase II trials of DHAC using this schedule.

Adult↗

PubMed1985

Differential protection of normal and malignant human myeloid progenitors (CFU-GM) from Ara-C toxicity using cycloheximide.

Cycloheximide, a reversible protein synthesis inhibitor, is thought to block DNA replication in normal cells by preventing synthesis of a labile protein. In animal systems, cycloheximide protects normal cells from cytotoxic S-phase specific agents, such as cytosine arabinoside (Ara-C). Malignant cells appear not to be susceptible to cycloheximide-induced cycle arrest and, subsequently, may not be protected from Ara-C cytotoxicity. The effect of cycloheximide on granulocyte/macrophage progenitors (CFU-GM) after in vitro Ara-C exposure was examined using normal human bone marrow, malignant progenitors from patients with chronic myelogenous leukemia (CML), and clonogenic cells from the human acute nonlymphocytic leukemia cell lines HL-60 and KG-1. Mononuclear or clonogenic cells were incubated for one hour with cycloheximide, followed by the addition, for three or 17 hours, of Ara-C before being plated in a methylcellulose culture system. CFU-GM survival was significantly increase if normal cells were treated with cycloheximide before Ara-C exposure. Similar cycloheximide pretreatment of CML progenitors and clonogenic HL-60 and KG-1 cells failed to protect CFU-GM from Ara-C-induced cytotoxicity.

AraC Transcription Factor↗

PubMed1985

Enrichment of myeloid progenitor cells from normal human bone marrow using an immune-rosette technique.

In this study we have developed methods for purification of myeloid progenitor cells (CFU-Cs) from normal human bone marrow cells. Bone marrow aspirates were obtained from volunteers, and mononuclear cells (MNCs) were separated by Ficoll-Hypaque gradient centrifugation. T- and B-lymphocytes, monocytes, mature granulocytes, and erythroid precursors were eliminated by an immune-rosette technique using a panel of murine monoclonal antibodies and immunoglobulin (Ig)-coated sheep red blood cells (SRBCs). MNCs were treated with OKT3, B1, M3, Mo5, and EP1 monoclonal antibodies, which are reactive with T cells, B cells, monocytes, granulocytes, and erythroid precursors, respectively. Antibody-treated MNCs were incubated with SRBCs that had been coated with goat antirabbit IgG F(ab')2 and rabbit antimouse Ig for immune rosetting. Rosetted cells were then separated from nonrosetted cells in Ficoll-Hypaque. Nonrosetted cells were, in the second step, treated with an OKIa1 monoclonal antibody and again separated into an Ia+ and Ia- cell fraction by the same manner; 39% +/- 19.2% (mean +/- 1 SD, range 16.3%-75.4%) of CFU-Cs (colonies plus clusters) were recovered in the OKT3-, B1-, M3-, Mo5-, EP1- cell fraction, and the number of CFU-Cs grown in semisolid agar was 149.6 +/- 73.0 (64.0-309.0)/10(4) plated cells in this purified fraction, representing an enrichment of 14.2 +/- 6.4 (6.0-27.3)-fold when compared with unseparated marrow cell fractions. CFU-Cs were enriched 17.7 +/- 8.6 (6.1-28.3)-fold in the Ia+ cell fraction. These purified myeloid precursors would be of value for in-depth studies of the interactions between hematopoietic progenitor cells and regulatory factors that influence their proliferation and differentiation and also of drug metabolism and determinants of cytotoxicity.

Adolescent↗

PubMed1984

Cancer chemotherapy. Progress and expectations, 1984.

Progress in the treatment of cancer with drugs has radically altered the clinical approach to patients with malignancy. Not only have new drugs produced promising results in hitherto untreatable tumors, but they have extended and enhanced the effectiveness of other modalities, including surgery and radiotherapy. In this article, the authors consider avenues of research that likely to aid in the discovery of new anticancer drugs and improve the effectiveness of established agents. Promising new efforts in drug development include the use of new screening systems, particularly those employing human tumor material; the development of improved analogs of existing active agents particularly those of the anthracycline and platinum complex types; and the search for agents that which promote differentiation or prevent metastasis. In an effort to improve the effectiveness of established agents, the authors consider the application of pharmacokinetic principles in developing regional perfusion routes, intraperitoneal chemotherapy, and central nervous system penetration. Finally, the contribution of biochemical pharmacology to the current understanding of drug action, mechanisms of resistance, and drug interactions are considered, and the impact of this knowledge on clinical protocol design is assessed.

Antineoplastic Agents↗

PubMedDate not supplied

Chronobiologic aspects of urinary gonadotropin peptide (UGP).

When using urinary gonadotropin peptide (UGP) as a marker for ovarian cancer, a circadian rhythm of large amplitude is best assessed for improving preanalytic quality control, for specifying how often and when to sample and for resolving chronobiologic endpoints. In a patient (EH, 73 y) with an ovarian (Müllerian) adenocarcinoma, overall high UGP values occurred consistently around 07:00 (standard deviation, SD = 2 h), similar to the timing observed in a presumably healthy woman. The circadian rhythm of EH averages in amplitude about 45% of the daily mean value (SD = 15%). The results indicate the desirability of deriving time-specified reference limits in health for an improved diagnostic value of UGP. The circadian UGP pattern awaits tests of applications for a chronodiagnosis of ovarian cancer, for optimizing treatment efficacy by timing according to rhythms, and conceivably for detecting earliest precancer risk.

Aged↗

PubMedDate not supplied

Biochemical modulation of doxorubicin by high-dose tamoxifen in the treatment of advanced hepatocellular carcinoma.

BACKGROUND/AIMS: In vitro data have indicated that tamoxifen (> 2.5 uM) significantly enhances the cytotoxic effect of doxorubicin in hepatocellular carcinoma (HCC) cells. This clinical study was conducted to examine whether tamoxifen, at a dose sufficient to result in a plasma concentration of more than 2.5 uM, may improve the therapeutic efficacy of doxorubicin in patients with advanced HCC. METHODOLOGY: A prospective phase II study was conducted. Eligible patients had unresectable and non-embolizable HCC, objectively measurable tumors, adequate neogram with absolute granulocyte count > 2,000/mm3 and platelet count > 1 x 10/mm3, total serum bilirubin < 3.0 mg/dl, age > or = 75 year, and a Karnofsky performance status < or = 50%. The treatment included oral tamoxifen 40 mg/m2, q.i.d, Day 1 to 7, and intravenous doxorubicin 60 mg/m2, Day 4, repeated every 3 weeks. RESULTS: Between May 1994 and December 1996, a total of 38 patients were enrolled in the study. Thirty-six patients were evaluable for tumor response and treatment-related toxicities. There were 32 men and 4 women, with a median age of 49 years. They received an average of 3.8 (range:1-12) courses of chemotherapy. ECOG (Eastern Cooperative Oncology Group) Grade 3-4 leucopenia and Grade 3-4 thrombocytopenia developed in 27.2% and 12.5% courses given, respectively. Gastrointestinal toxicity was generally mild. Three patients developed symptomatic cardiac toxicity. Twelve patients (33.3%, 95% confidence interval 17-51%) had achieved a partial remission (PR), with a median progression-free survival of 7 months. Median survivals of the responders and non-responders were 10 and 3 months, respectively (p<0.05). The median Karnofsky performance status of the responders improved from 74.0+/-6.3% to a post-chemotherapy value of 93.2+/-4.6% (p<0.05) CONCLUSIONS: High dose tamoxifen appears to be an effective biochemical modulator of doxorubicin in the treatment of HCC. Prospective randomized phase III studies comparing doxorubicin alone versus doxorubicin plus high-dose tamoxifen are needed.

Adult↗