PubMed Health⌕ Search

Biomedical subjects

E Cadman

Publications and source records attributed to E Cadman.

At least 37 records · Page 2Linked to original sources
PubMed1984

Cytotoxicity of several chemotherapeutic agents in a human pancreatic cancer cell line (Colo-357).

Seven commonly available chemotherapeutic drugs were used to determine the concentration and time of exposure necessary to kill the newly available human pancreatic cancer cell line, Colo-357. The exposure periods were 2, 6, 12, and 24 hours. The most active drugs were methotrexate, mitomycin, and doxorubicin, each with an ID50 less than 0.1 microM for both a 12- and a 24-hour exposure. Cisplatin was intermediate, with an ID50 of approximately 0.7 microM at 12 and 24 hours. 5-FU, carmustine, and streptozocin were the least effective agents, with ID50 values greater than 50 microM after a 12-hour exposure and greater than 25 microM after a 24-hour exposure.

Antineoplastic Agents↗
PubMed1983

Sclerosing variants of follicular center cell lymphomas presenting in the retroperitoneum.

A study of 22 patients with sclerosing variants of follicular center cell lymphoma (FCCL) presenting as a retroperitoneal mass is reported. These FCCL variants comprise 74% of retroperitoneal non-Hodgkin's lymphoma presentations. A partial intranodal follicular growth pattern was present in each case, and marked sclerosis of a distinctive pattern was associated with extensive perinodal lymphomatous infiltration. Small cleaved cells (SCC) predominated in five cases, large cleaved cells (LCC) in 14, and large noncleaved cells (LNCC) in three. Eighty percent of patients with SCC predominance were Stage I-II, compared to 50% of those with LCC predominance; all three LNCC cases were Stage IV. High stage was attained primarily by renal invasion or infiltration out the mesenteric root into gut or omentum; only three patients had biopsy proven extraabdominal disease. Combined modality therapy achieved an 88% complete or partial remission rate in patients with SCC and LCC predominance; all three LNCC patients died.

Adenocarcinoma↗
PubMed1983

Modulation of fluoropyrimidine metabolism in L1210 cells by L-alanosine.

L-Alanosine, an analogue of aspartic acid which inhibits the conversion of inosine monophosphate to adenosine monophosphate (AMP), was evaluated in L1210 cells as a modulator of 5-fluorouracil (FUra) and 5-fluorouridine (FUrd) metabolism. L-Alanosine resulted in increased intra-cellular levels of 5-phosphoribosyl-1-pyrophosphate (PRPP), enhanced FUra metabolism to ribonucleotide derivatives, and resulted in more FUra residues incorporated into RNA. Sequential addition of L-alanosine and FUra also resulted in synergistic cytotoxicity as determined by soft agar cloning. Adenine antagonized these biochemical and biological effects of L-alanosine. L-Alanosine also augmented the rate at which FUrd was metabolized and was also associated with a greater incorporation of the FUra residues into RNA. Cytotoxicity after sequential L-alanosine and FUrd was also synergistic. The mechanism by which L-alanosine altered the metabolism of FUrd, however, was different from the way in which it enhanced FUra metabolism in that aspartic acid and not adenine was able to reverse the effects of L-alanosine on FUrd metabolism and cytotoxicity. L-Alanosine appeared to augment the RNA-directed activity of FUra and FUrd in that there was no correlation between the enhanced metabolism and cytotoxicity of these two fluoropyrimidines and either levels of fluorodeoxyuridylate (FdUMP) which inhibits thymidylate (TMP) synthetase or inhibition of the ability of cells to incorporate deoxyuridylate into acid-precipitable material.

Adenine↗
PubMed1983

Mechanism of cytotoxic activity of 5'-deoxy-5-fluorouridine.

The purpose of these studies was to characterize the effect of the new fluoropyrimidine nucleoside 5'-deoxy-5-fluorouridine (5'dFUrd) on macromolecular processes in correlation with its cytotoxicity in Ehrlich ascites tumor cells. Following a 2-h exposure, 5'-dFUrd exhibited an LD50 (as determined by clonogenicity) of 48 microM. In cells supplemented with 10 microM dThd, the LD50 for 5'-dFUrd increased to 660 microM. DNA synthesis was markedly and rapidly suppressed by all cytotoxic concentrations of 5'-dFUrd. There was no apparent direct measurable effect of 5'-dFUrd on either RNA or protein synthesis, although both were suppressed 24 h after the drug exposure. Thymidylate synthetase activity was completely inhibited by all cytotoxic concentrations of 5'-dFUrd. FUra incorporation into RNA was also measured and appeared to correlate with the dThd-nonreversible toxicity of 5'-dFUrd. These studies indicate that the mechanism of 5'-dFUrd cytotoxicity is directly analogous to that reported for 5-fluorouracil. The inhibition of thymidylate synthetase leading to an inhibition of DNA synthesis was the most potent cytotoxic mechanism (i.e., dThd-reversible) for 5'-dFUrd, and was found to be highly time-dependent. Higher concentrations of 5'-dFUrd resulted in dThd-nonreversible toxicity, which appeared to be related to the incorporation of FUra into RNA.

Animals↗
PubMed1983

The presence of phospholipase A and lysophospholipase activities in culture supernatant fluid from Alteromonas espejiana.

Culture supernatants from late Log phase cultures of Alteromonas espejiana hydrolyzed phosphatidylinositol to glycerylphosphorylinositol and free fatty acid. No lysophosphatidylimositol was detected. The phospholipase activity degraded up to 50% of the substrate and displayed a broad pH optimum from 6.5-8.5. The activity was slightly stimulated in the presence of either Mg2+ or Ca2+, but was not inhibited by EDTA. The apparent Km for phosphatidylinositol was 1.5 mM. Culture supernatants also contained deacylating activity which released fatty acid from phosphatidylcholine and erythrocyte ghosts.

Bacteria↗
PubMed1983

The effective use of combined modality therapy for the treatment of patients with Hodgkin's disease who relapsed following radiotherapy.

From 1969 to 1977, 124 patients with advanced staged Hodgkin's disease were entered into a treatment protocol which consisted of three cycles of drugs (nitrogen mustard, vincristine, vinblastine, prednisone, and procarbazine) followed by radiation (1500-2000 rad) to previous sites of known disease. After completion of radiation therapy, two more drug cycles were given. There were 63 newly diagnosed patients with Stage IIIB and IVA or B disease and 61 patients who had relapsed from prior radiotherapy. The median follow-up is now in excess of 5 years. Of the relapsed patients, 86.9% entered a complete remission and 90.6% of these patients have remained in complete remission from 1 to 10 years. In comparison, 81% of the newly diagnosed patients entered a complete remission and 78.4% of these patients continue free of disease from 1 to 11 years. These differences were not statistically significant. The 10-year actuarial disease-free survival--79.8% for the 61 relapsed patients compared to 65.6% for the 63 newly diagnosed patients--was not significantly different either. The 10-year actuarial survival for the 40 patients who had relapsed to IIIB and IVA or B was 71.3% and approximated more closely those of newly diagnosed IIIB and IVA or B patients. This drug-radiotherapy protocol is very effective for the treatment of patients who have relapsed from previous radiotherapy.

Drug Therapy, Combination↗
PubMed1983

Survival of women with metastatic breast cancer at Yale from 1920 to 1980.

The tumor registry at Yale--New Haven Hospital, which began recording data in 1920, was utilized to examine the ultimate outcome of all breast cancer patients who were initially diagnosed at Yale with metastatic breast cancer. Of the 5,898 patients with breast cancer seen from 1920 to 1980, 574 initially had metastatic cancer. The median survival of these patients increased steadily from 21 months in 1920 to 41 months in the decade from 1970 to 1980. The percentage of women actually surviving 5 years increased from 5% in the 1920s to approximately 25% in the 1960s. Despite the use of combination drug programs in the 1970s, the percentage of these patients remaining alive at 5 years remained near 25%. Firm conclusions cannot be made from a retrospective study spanning 60 years, although the trends depicted and lack of continued improvement indicate that our current therapeutic approach to metastatic breast cancer may not result in dramatic improvement in overall survival.

Breast Neoplasms↗
PubMed1983

Biochemical and cytokinetic modulation of L1210 and HL-60 cells by hydroxyurea and effect on 1-beta-D-arabinofuranosylcytosine metabolism and cytotoxicity.

The modulating effect of hydroxyurea (HU) on 1-beta-D-arabinofuranosylcytosine (ara-C) metabolism and cytotoxicity was evaluated in L1210 cells and the human promyelocytic leukemic cells HL-60. A dose- and time-dependent HU exposure was observed which resulted in maximum deoxycytidine 5'-triphosphate reduction, intracellular ara-C accumulation, 1-beta-D-arabinofuranosylcytosine 5'-triphosphate formation, and cytotoxicity as determined by soft agar cloning. For the L1210 cells, a 5-hr pretreatment of 5 mM HU was optimum. The best result obtained with the HL-60 cells was after a 24-hr exposure of 1 mM HU. There was also a maximum incorporation of ara-C into DNA in both cells following these optimal pretreatment conditions. Cytofluorometric analysis demonstrated that this HU treatment resulted in a maximum accumulation of L1210 and HL-60 cells in the pre-S phase of the cell cycle and that after removal of the HU there was a rapid progression of the cell population through S phase. Because cytotoxicity of ara-C is considered to be predominantly from the inhibition of DNA polymerase and/or the incorporation into DNA, the cytokinetic and biochemical modulatory effects of HU must both be contributing factors to consider in achieving maximal cell kill from this drug sequence.

Animals↗
PubMed1983

5'-Deoxy-5-fluorouridine selective toxicity for human tumor cells compared to human bone marrow.

Studies were completed to establish the comparative cytotoxicity of 5'-deoxy-5-fluorouridine (5'-dFUrd) and other fluoropyrimidines in human bone marrow stem cells and several cultured human tumor cell lines (i.e., 47-DN and MCF-7 breast carcinomas, MG-63 osteosarcoma, HCT-8 colon tumor, Colo-357 pancreatic tumor, and HL-60 promyelocytic leukemia). In vitro clonogenic assays were used to measure cytotoxicity following a 3-hr drug exposure. 5'-dFUrd was less potent than was 5-fluorouracil or 5-fluoro-2'-deoxyuridine in all cells examined, exhibiting its best activity against the 47-DN [concentration that prevented 50% clonal growth compared to untreated control (LD50) = 32 microM] and MCF-7 (LD50 = 35 microM) breast carcinomas and MG-63 osteosarcoma (LD50 = 41 microM). Intermediate activity was observed against HCT-8 (LD50 = 200 microM) and Colo-357 (LD50 = 150 microM) gastrointestinal tumors. 5'-dFUrd had very poor activity against the HL-60 leukemia (LD50 = 470 microM). The suppression of the clonal growth of human bone marrow stem cells required the greatest amount of 5'-dFUrd (LD50 = 580 microM). With use of these studies, a therapeutic ratio (concentration that prevented 25% clonal growth compared to untreated control of bone marrow divided by LD50 of tumor) was calculated for each drug in each tumor. 5'-dFUrd had values ranging from 1.2 to 7.5 for the solid tumors and 0.5 in HL-60 cells. This was in marked contrast to 5-fluorouracil, or 5-fluoro-2'-deoxyuridine, which failed in all cases to have ratios greater than or equal to one. The results indicate that 5'-dFUrd can exhibit a cytotoxic selectivity for human tumor cells compared to human bone marrow stem cells that does not exist for 5-fluorouracil or 5-fluoro-2'-deoxyuridine. This suggests that 5'-dFUrd may be of greater therapeutic benefit in the treatment of certain human cancers than the fluoropyrimidines used currently.

Antineoplastic Agents↗
PubMed1983

Cytotoxic activity of 5'-deoxy-5-fluorouridine in cultured human tumors.

The cytotoxic activity of 5'-deoxy-5-fluorouridine (5'-ddFUrd) was established in six cultured human tumor lines: 47-DN and MCF-7 breast carcinomas, MG-63 osteosarcoma, HCT-8 colon carcinoma, Colo-357 pancreatic carcinoma, and HL-60 promyelocytic leukemia. Cells were exposed to a wide range of 5'-dFUrd concentrations (from 0.1 microM to 1.0 mM) for 3, 6, or 24 hrs, and then cloned using standard in vitro clonogenic assays. 5'-dFUrd exhibited its best activity in the 47-DN and MCF-7 breast cell lines and in the MG-63 osteosarcoma line (3-hr LD50 values of 32, 34, and 38 microM, respectively). Less activity was observed in the HCT-8 colon (LD50 = 195 microM) and Colo-357 pancreatic (LD50 = 155 microM) tumor lines, and ver poor activity was noted in the HL-60 leukemia cell line (LD50 = 465 microM). The metabolism of 5'-dFUrd to 5-FU (FUra) and FUra-nucleotides was determined and found to directly correlate with the potency of 5'-FUrd in these cell lines. These results suggest that: (a) there is a marked variation in sensitivity of human cancer cells of different tissue origin to 5'-dFUrd, (b) there is a direct relationship between the sensitivity of human cells to 5'-dFUrd and the ability of the cell to metabolize 5'-dFUrd to FUra, and (c) increasing exposure period of cells to 5'-dFUrd did not markedly alter 5'-dFUrd potency in all human cancer cells examined, with the exception of the 47-DN breast cancer cells.

Breast Neoplasms↗
PubMed1983

Potentiation of 1-beta-D-arabinofuranosylcytosine metabolism and cytotoxicity by 2,3-dihydro-1H-imidazolo[1,2-b]pyrazole in the human promyelocytic leukemic cell, HL-60.

The effect of IMPY (2,3-dihydro-1H-imidazolo[1,2-b]pyrazole) on the metabolism and cytotoxicity of subsequently administered 1-beta-D-arabinofuranosylcytosine (ara-C) was examined in the human promyelocytic leukemic cell line HL-60. Cells exposed to 3 mM IMPY for 12 hr followed by a 1-hr exposure to 1 microM [3H]ara-C accumulated 27.5 +/- 4.8 (S.D.) pmol ara-C/10(6) cells compared to 14.0 +/- 3.5 pmol/10(6) cells in untreated controls. Cells experienced greater than a 2-fold increment in 1-beta-D-arabinofuranosylcytosine 5'-triphosphate generation and retention following this same IMPY exposure and nearly a 4-fold increment in incorporation of ara-C into HL-60 nucleic acids. These alterations in ara-C metabolism were associated with a 36% reduction in the intracellular concentration of deoxycytidine 5'-triphosphate and reductions in deoxyadenosine 5'-triphosphate and deoxyguanosine 5'-triphosphate concentrations to undetectable levels. Coincubation of cells with IMPY along with other pyrimidine antagonists such as thymidine, N-(phosphonacetyl-L-aspartate), deoxyadenosine, and deoxyguanosine, produced up to 4-fold increments in ara-C intracellular accumulation. Pretreatment of HL-60 cells with 3 mM IMPY followed by a continuous exposure to 10 nM ara-C produced synergistic inhibitory effects on both suspension culture growth and soft agar clonogenicity. In contrast, exposure of normal human bone marrow progenitor cells (CFU-GM) to the same schedule of IMPY and ara-C produced subadditive or antagonistic effects on the growth of these cells in soft agar. These findings may have implications for the design of in vivo regimens using IMPY and ara-C.

Antineoplastic Agents↗
PubMed1983

Tamoxifen and 5-fluorouracil in breast cancer: cytotoxic synergism in vitro.

The cytokinetic and cytotoxic interactions involved in combining tamoxifen, methotrexate, and 5-fluorouracil were studied in two hormone-dependent human breast cancer cell lines, 47-DN and MCF-7. These cells had measurable cytosol and nuclear estrogen receptor and cytosol progesterone receptor. Growth of the MCF-7 cells in medium containing gelding serum was stimulated maximally by addition of 10 pM estradiol. Both MCF-7 and 47-DN cells showed dose-dependent in vitro growth inhibition on exposure to tamoxifen, and toxicity from tamoxifen at concentrations up to 10 microM could be prevented by 1 nM estradiol. After exposure of 47-DN cells to 10 microM tamoxifen, cytosol progesterone and nuclear estrogen receptor levels were still detectable at 30 and 60% of control values. With this same concentration of tamoxifen, 47-DN cells in S phase declined 50% in association with a buildup of G0-1 cells. By clonogenic assay, tamoxifen enhanced 47-DN and MCF-7 cytotoxicity to 5-fluorouracil and 5-fluorouridine, but not to methotrexate alone. When given either concurrently or using a pretreatment-synchronizing schedule, tamoxifen enhanced markedly the growth inhibition of sequentially combined methotrexate and 5-fluorouracil. Isobologram analysis was used to prove that the cytotoxic interaction between tamoxifen and 5-fluorouracil was synergistic.

Breast Neoplasms↗
PubMed1983

Tamoxifen and 5-fluorouracil in breast cancer: modulation of cellular RNA.

Biochemical studies were undertaken with the human breast carcinoma cell line, 47-DN, to explore the mechanisms underlying cytotoxic synergy between tamoxifen (TAM) and the fluoropyrimidines, 5-fluorouracil (FUra) and 5-fluorouridine (FUrd). The influence of TAM pretreatment was measured on intracellular FUra accumulation, FUra nucleotide formation, and incorporation of fluoropyrimidines into cellular RNA. Unlike other modulators of FUra metabolism and toxicity. TAM decreased intracellular FUra accumulation and total RNA incorporation by 20 to 60%. Cells treated with TAM contained 10 to 20% less cellular RNA and showed reduced transcription and altered RNA turnover, independent of fluoropyrimidine treatment. Newly synthesized RNA from control and TAM-treated cells was fractionated by sucrose gradient centrifugation. The specific incorporation of FUrd (2 hr) was compared to that of FUra (6 hr) and labeled uridine incorporation into controls. Compared to its effect on uridine incorporation, TAM produced nearly twice as much FUra incorporation and 3 times as much FUra incorporation into 32 to 45S RNA. Since accumulation of this high-molecular-weight RNA has been associated with fluoropyrimidine toxicity and impaired ribosomal RNA processing, it is believed that TAM enriched the RNA-mediated toxicity of FUra and FUrd in this breast carcinoma cell line.

Breast Neoplasms↗
PubMed1983

Use of high-dose oral methotrexate sequenced at 24 hours with 5-FU: a clinical toxicity study.

Twenty-three patients with advanced carcinoma were treated with 131 courses of high-dose oral methotrexate (MTX), sequenced at 24 hours with 5-FU iv and subsequent leucovorin rescue. The 30% incidence of toxicity was predominantly mild to moderate mucositis and myelosuppression. Trough and peak serum MTX levels demonstrated that micromolar concentrations were sustained greater than 24 hours. Toxicity correlated with shorter re-treatment intervals and not with serum MTX levels. This regimen can be safely and conveniently administered to an outpatient population and deserves further assessment in phase II trials.

Breast Neoplasms↗
PubMed1982

High-dose pulse chlorambucil: effective therapy for rapid remission induction in nodular lymphocytic poorly differentiated lymphoma.

Eighteen patients with Stage III or IV nodular poorly differentiated lymphocytic lymphoma (malignant lymphoma, infiltrative nodular type, with predominately small cleaved cells) were treated with intermittent high-dose oral chlorambucil (16 mg/m2 daily for five consecutive days each month) for one year. Complete clinical remissions occurred in 78% of these patients and partial remissions in another 17%. Complete remission usually occurred within three months of beginning therapy and with a medial follow-up of 35 months no patient has relapsed. Toxicity, usually hematologic and occurring late in therapy, has been mild, necessitating termination of therapy in only one patient. Review of recent therapy fails to demonstrate a definite long-term advantage of more aggressive treatment regimens. Intermittent high-dose chlorambucil should be further evaluated as therapy for nodular poorly differentiated lymphocytic lymphoma.

Adult↗
PubMed1982

The use of cisplatinum for treatment of malignant glioma.

Standard chemotherapy for malignant gliomas has not generally been successful. Recent reports have suggested that cis-diammine-dichloroplatinum is preferentially accumulated into brain tumors compared to surrounding brain tissue. A patient who had failed radiation treatments and multiple other chemotherapeutic agents responded both clinically and radiographically to this new drug. This clinical observation, when combined with the tissue distribution of cis-diamminedichloroplatinum, would indicate that further evaluation of this new agent in the treatment of brain malignancies is warranted.

Brain Neoplasms↗
PubMed1982

Dose- and schedule-dependent activation and drug synergism between thymidine and 5-aza-2'-deoxycytidine in a human promyelocytic leukemia cell line.

The ability of thymidine (dThd) to enhance the metabolism and cytotoxicity of subsequent administered 5-aza-2'-deoxycytidine (5-aza-dCyd) was studied in L1210 cells and in the human promyelocytic leukemic cell line, HL-60. Exposure of L1210 cells to 0.1 mM dThd for 5 h resulted in an increase in the total intracellular and acid-precipitable accumulation of 5-aza-dCyd. Higher dThd concentrations and longer exposure intervals resulted in smaller increments in 5-aza-dCyd accumulation. In contrast, in HL-60 cells, a 24-hr exposure in 1 mM dThd resulted in the greatest intracellular accumulation of 5-aza-dCyd, 3.3 times more accumulation than in control cells. There was also a 4-fold increase in the acid-precipitable accumulation and nearly a 3-fold increase in DNA incorporation of 5-aza-dCyd in HL-60 cells exposed to the same dThd schedule. High-pressure liquid chromatographic analysis demonstrated a greater than 3-fold increase in the intracellular amounts of 5-aza-dCyd metabolites eluting in the triphosphate region in these human cells under identical conditions. Shorter dThd incubation exposure intervals (6 hr) and lower dThd concentration (0.1 mM) produced smaller increments in these studies. Both growth and clonogenic assays of HL-60 cells demonstrated a dose- and schedule sequence-dependent synergism between dThd and 5-aza-dCyd.

Animals↗