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Biomedical subjects

C N Coleman

Publications and source records attributed to C N Coleman.

At least 91 records · Page 5Linked to original sources
PubMed1993

Wide-field radiation therapy with or without chemotherapy for patients with Hodgkin disease in relapse after initial combination chemotherapy.

BACKGROUND: Patients with Hodgkin disease who have relapses after initial chemotherapy (CT) appear to have a poor prognosis, especially if the duration of the first complete remission (CR) was short. The authors performed a retrospective analysis of patients with Hodgkin disease whose relapse after combination CT was limited to nodal sites; their aim was to study the prognosis of this selected subgroup of patients. METHODS: In 28 patients with Hodgkin disease who had relapses in nodal sites after combination CT alone, the disease was restaged carefully to rule out simultaneous extranodal recurrences. Then the patients were treated with wide-field, high-dose radiation therapy (RT) with or without additional CT with curative intent between 1971 and 1987 at the Joint Center for Radiation Therapy. Fourteen patients were in first relapse and were treated with combination CT followed by RT. The remaining 14 patients (8 who were in first relapse and 6 who were in second relapse) were treated with RT alone. RT techniques were similar to those recommended for early-stage disease. RESULTS: The 7-year actuarial freedom from relapse and survival rates for the patients retreated with CT and RT were 93% and 85%, respectively, as compared with 36% and 36% for patients retreated with RT alone. There was a significant difference for freedom from relapse (P = 0.002) and survival (P = 0.03), favoring patients retreated with both CT and RT. CONCLUSIONS: This retrospective study demonstrates that RT combined with second-line CT can result in a high percentage of durable remissions in patients who have relapses primarily in nodal sites after original treatment with combination CT alone. These durable remissions are seen even in patients who have only a brief CR after initial CT.

Adolescent↗
PubMed1993

Increases in sequence specific DNA binding by p53 following treatment with chemotherapeutic and DNA damaging agents.

We have investigated the effect of chemotherapeutic and DNA damaging agents on binding of the tumor suppressor phosphoprotein p53 to its consensus DNA sequence. Activation of p53-DNA binding was seen for treatment with radiation, hydrogen peroxide, actinomycin D, Adriamycin, etoposide, camptothecin, 5-fluorouracil, mitomycin C, and cisplatin. These results showed that DNA strand breaks were sufficient to lead to increased levels of p53. The protein synthesis inhibitor cycloheximide blocks the increase in p53 following DNA damage. The increase in p53 activation in camptothecin treated cells may result, at least in part, from an increased half-life of the protein and consequent increases in intracellular protein concentration.

3T3 Cells↗
PubMed1993

Prognostic factors for patients with Hodgkin disease in first relapse.

BACKGROUND: This study aims to identify factors that predict outcome after salvage therapy for patients with Hodgkin disease (HD) in first relapse. METHODS: Between 1969 and 1985, 627 patients with Pathologic Stage IA-IIIB HD were treated at the Joint Center for Radiation Therapy. With a median follow-up time for survivors of 135 months, 138 patients (22%) have experienced relapse. One hundred twenty-seven of these were retreated with curative intent and form the basis of this report. RESULTS: The complete response (CR) rate after retreatment was 79%. The 10-year actuarial freedom from second relapse (FSR) was 53%, and the 10-year survival rate from the time of first relapse was 57%. For patients experiencing relapse after initial radiation therapy (RT) alone (n = 110), the 10-year FSR and overall survival rates were 58% and 62%, respectively. Histologic type was the single most important prognostic factor for second CR rate, FSR, and survival. Patients with nodular sclerosis or lymphocyte predominant (NS/LP) histologic type had a 91% second CR rate, 67% 10-year FSR rate, and 75% 10-year survival rate, compared with 66%, 44%, and 43%, respectively, for patients with mixed cellularity or lymphocyte depleted (MC/LD) histologic type. For patients who experienced relapse after initial combined modality therapy (CMT; n = 17), the 10-year FSR and overall survival rates were 13% and 24%, respectively. CONCLUSION: This study demonstrates that patients who experience relapse after RT alone can be effectively salvaged with combination chemotherapy. The implications of these results for clinical decision making are discussed.

Adult↗
PubMed1993

Patterns of presentation of Hodgkin disease. Implications for etiology and pathogenesis.

BACKGROUND: The etiology of Hodgkin disease remains uncertain. Patterns of presentation of Hodgkin disease are analyzed by histologic subtype with implications for etiology and pathogenesis. METHODS: The authors performed a detailed analysis of anatomic sites of involvement, histopathologic findings, and clinical features in 719 patients with Hodgkin disease who underwent staging laparotomy with splenectomy between April 1969 and December 1986. The presence of disease in each of 17 sites of potential nodal involvement was determined for each patient from a combination of clinical and surgical staging. Association among nodal sites was assessed in 2 x 2 tables by estimating the odds ratio and testing the significance with the chi-square test. A strict significance level (P = 0.01) was used. Log-linear models were used for assessing association in 2 x 2 tables while adjusting for other factors. RESULTS: The mediastinum, left side of neck, and right side of neck were the most common sites involved for patients with nodular sclerosing (NS) or mixed cellularity (MC) histologic subtypes. Each of these sites was involved 60% of the time. These sites were four or more times as common as other nodal sites above or below the diaphragm. In contrast, the mediastinum was involved in only 8% of patients with lymphocyte predominance (LP) histologic subtype. Significant associations were found between mediastinal disease and low cervical/supraclavicular lymph node disease, mediastinal disease and NS histologic subtypes, peripheral nodal disease and LP histologic subtypes, and between splenic disease and mixed cellularity/lymphocyte depletion (MC/LD) Hodgkin disease. The age at onset and sex of patients with Hodgkin disease and the patterns of nodal distribution were somewhat different for NS and MC/LD histologic subtypes. Even greater differences were seen between LP and other histologic subtypes. CONCLUSIONS: This study supports the conclusion that NS and MC Hodgkin disease spread by continguity, most often originating in the neck or mediastinum, and is consistent with evidence suggesting an infectious agent in the pathogenesis of these subtypes of Hodgkin disease. In contrast, LP Hodgkin disease is characterized by different sites of presentation and patterns of spread. This suggests that two or perhaps three clinicopathologic subtypes of Hodgkin disease exist. Implications for etiology and pathogenesis are discussed.

Adult↗
PubMed1993

Oxidative injury rapidly activates the heat shock transcription factor but fails to increase levels of heat shock proteins.

When cells are exposed to heat shock, heavy metals, amino acid analogues, and other stresses, the heat shock transcription factor (HSF) is activated. The HSF then binds to the promoter of the heat shock genes, stimulating transcription of the heat shock proteins. Here, we demonstrate that exposure of NIH-3T3 cells to oxidants (H2O2 or menadione) also causes activation of the HSF. This activation is not blocked by inhibitors of protein synthesis (cycloheximide) or by inhibitors of protein kinases (2-aminopurine or genistein). In addition, the oxidant activated HSF is located in the nucleus of the cells. However, oxidant activation of the HSF does not result in the accumulation of hsp70 mRNA or of heat shock proteins. This is in contrast to the accumulation of heat shock proteins seen after heat shock activation of the HSF. This suggests that oxidant induced activation of HSF binding may have a function different from that of heat induced activation of HSF binding.

3T3 Cells↗
PubMed1993

Beneficial liaisons: radiobiology meets cellular and molecular biology.

The scientific knowledge that is emerging in all fields of medicine is rapidly changing our understanding of the concepts in radiation oncology. In this review, some of the classic radiation biology theories and models are examined and newer 'models' are illustrated. The ability of radiation oncologists to remain current with the newer scientific findings is essential to the development of improved therapeutic strategies and, importantly, to the proper balance between investment in technology and biology.

Cell Cycle↗
PubMed1993

Mutagenesis after cancer therapy.

A subset of Hodgkin's disease (HD) and breast cancer patients have been reported to have elevated hprt mutant frequencies in peripheral blood lymphocytes after cessation of therapy. A subset of these patients are also known to develop second therapy-related malignancies. Therefore, it is clearly important to determine if these elevations in mutant frequency represent true, persistently elevated mutation frequencies. As a follow-up to our study of patients previously treated for HD, we recruited for a prospective study six previously treated HD patients and five patients who had been treated for squamous cell carcinoma of the head and neck. These individuals were studied several times over a 6-7 months. The results confirmed that a subset of patients have persistently high mutant frequencies when compared to 71 previously studied controls. The study was designed to determine if the elevated mutant frequencies of treated patients represented independent mutations or resulted from the in vivo expansion of single mutant cells. We used the polymerase chain reaction to examine DNA single strand conformation polymorphisms at the T-cell receptor-gamma locus of individual mutant clones. This analysis showed that 20.1% of the mutants from Hodgkin's disease patients and 17.5% of the mutants from squamous cell carcinoma patients were siblings. The sibling mutants generally did not persist over time. However, one patient had one mutant clone that persisted, but slowly decreased in prevalence over a 7 month sampling period. The data demonstrate that treatments for cancer result in persistently elevated mutation frequencies at the hprt locus in some, but not all, patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Modifiers of radiation-induced apoptosis.

EL4 murine lymphoma cells and F9 murine teratocarcinoma cells undergo apoptosis-like cell death after exposure to ionizing radiation. Apoptosis differs in several ways from classical clonogenic cell killing by radiation. We have tested several modifiers and radiomimetic agents in an effort to determine if the mechanism of induction of apoptosis by radiation differs from the mechanism of classical clonogenic cell killing by radiation, and consequently that these two end points of radiation action might be differentially modifiable. We found that internucleosomal DNA fragmentation, characteristics of apoptosis, can result from treatment of EL4 and F9 cells with agents that have diverse modes of action: tert-butyl hydroperoxide, diazenedicarboxylic acid bis(N,N-piperidide), and etoposide. Hydrogen peroxide did not induce internucleosomal DNA fragmentation at concentrations expected to be produced by the doses of ionizing radiation that we used. Radiation-induced DNA fragmentation could be inhibited by 3-aminobenzamide, dibutryl cyclic AMP, or 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, although in this respect there appear to be marked differences between the cell lines.

Animals↗
PubMed1993

Mutagenesis after therapy for Hodgkin's disease.

Therapy for Hodgkin's disease has been associated with a significant increase in risk for second cancers. To begin an investigation of the association of therapy-induced genetic damage with this risk, somatic mutations at the hypoxanthine phosphoribosyltransferase locus were measured in lymphocytes from patients previously treated for Hodgkin's disease. The results demonstrate that a subset of patients have persistently elevated mutation frequencies, perhaps suggesting that these individuals are among those at significant risk of second cancer development.

Adolescent↗
PubMed1992

Enhancement of alkylating agent activity by SR-4233 in the FSaIIC murine fibrosarcoma.

BACKGROUND: The most commonly used antineoplastic drugs are more cytotoxic toward normally oxygenated tumor cells than toward hypoxic tumor cells. PURPOSE AND METHODS: To examine the ability of SR-4233, a new cytotoxic agent, to overcome the resistance of hypoxic tumor cells to antitumor alkylating agents, we tested the cytotoxic effect of SR-4233 alone and in combination with varying doses of cisplatin (CDDP), cyclophosphamide (CPM), carmustine (BCNU), or melphalan (L-PAM) on tumor cells and bone marrow cells isolated from C3H/FeJ mice bearing the FSaIIC fibrosarcoma. RESULTS: When SR-4233 alone was given, tumor cell killing was limited. When SR-4233 was administered just before single-dose treatment with CDDP, CPM, BCNU, or L-PAM, however, marked dose enhancement leading to increased cytotoxic effects on tumor cells and on bone marrow cells was observed. Similar experiments with tumor cell subpopulations, selected by Hoechst 33342 dye diffusion, confirmed that while cytotoxicity to both bright (oxygenated) and dim (hypoxic) cells was increased by combining each alkylating agent with SR-4233, the enhancement of the effect was relatively greater in the subpopulation of dim cells. The delay in the growth of tumors in animals treated with the combination of SR-4233 and CDDP, CPM, or L-PAM was 1.6-fold to 5.3-fold greater than that in animals treated with each alkylating agent alone. CONCLUSION: Our results suggest that SR-4233 may have the potential to improve the clinical efficacy of commonly used antitumor alkylating agents.

Alkylating Agents↗
PubMed1992

Elevation of mouse kidney thiol content following administration of glutathione.

We have found that kidney glutathione and cysteine content in C3H mice can be increased by intraperitoneal administration of either glutathione (GSH) or glutathione disulfide (GSSG). Kidney thiol content is maximal 20-60 min after administration of 1000 mg/kg glutathione and returns to normal values by 2 h. The same time-course of thiol perturbation was observed when acivicin, an inhibitor of gamma-glutamyl transpeptidase, was administered 15 min prior to GSSG administration. The increase in kidney thiols after GSSG administration appears to saturate, with little additional increase as the administered dose is increased above 750 mg/kg. There was no significant change in liver GSH or cysteine after GSSG administration. We suggest that glutathione administration may provide a strategy for selective radioprotection or chemoprotection of specialized cells which can effectively utilize systemic GSH precursors.

Animals↗
PubMed1992

Sensitization of Chinese hamster ovary cells to melphalan by etanidazole under intermittent hypoxia.

Incubation of Chinese hamster ovary cells with etanidazole under hypoxic conditions increases cell killing by subsequent treatment with melphalan under aerobic conditions. We report here that this sensitization can be achieved even if periods of hypoxia are interrupted by reoxygenation. Preincubation under hypoxia in the absence of etanidazole also results in sensitization to melphalan. Intermittent hypoxia is less effective than continuous hypoxia as a single sensitizing factor. Glutathione depletion does not appear to have more than an additive effect on chemosensitization by etanidazole. These results suggest that prolonged treatment with low doses of etanidazole may be a more effective strategy for clinical chemosensitization than a short exposure to a higher dose, in order to target intermittently as well as chronically hypoxic cells.

Animals↗
PubMed1992

The efficacy of pharmacokinetic monitoring and dose modification of etanidazole on the incidence of neurotoxicity: results from a phase II trial of etanidazole and radiation therapy in locally advanced prostate cancer.

Fifty-four patients have been entered on a Phase II trial to study the efficacy of etanidazole (ETA) for locally advanced prostate cancer. The primary goal was to study the incidence of and time to a complete response for patients receiving ETA and radiation therapy. The secondary goal was to prospectively evaluate the utility of pharmacokinetic monitoring and dose-modification of the incidence and severity of the dose-limiting peripheral neurotoxicity. Within a constant radiation therapy regimen, the dose of ETA was either (a) unmodified (2 g/m2, 3 times weekly for 17 doses); (b) altered by a schedule modification of either number of doses or dose adjustment; or (c) individualization of single dose size so that the total number of doses (19 doses) were maintained but the single dose size was adjusted to keep the total AUC of plasma concentration versus time to less than 40 mM-hr. Sufficient efficacy data are not yet available. The use of drug dose modification has reduced the incidence of neurotoxicity from (a) unmodified: 17/26 = 65% (1 grade II); (b) schedule adjustment: 5/9 = 55% (no grade II); and (c) individualized dose modification: 1/19 (no grade II) = 6%. The minimum number of time points needed to accurately assess the AUC will be determined. Pharmacokinetic monitoring will be important in the use of ETA so that drug underdosing can be avoided while minimizing the risk of serious neurotoxicity.

Adenocarcinoma↗
PubMed1992

Logistics in designing clinical trials for etanidazole (SR 2508): an RTOG experience.

In a Phase II study of etanidazole (SR 2508), the dose of 17 x 2 g/m2 (total drug dose: 34 g/m2) was tested in 33 patients and the toxicity was deemed acceptable. A Phase III trial is now in progress comparing conventional radiotherapy with conventional radiotherapy plus etandizole (2 g/m2 i.v. 30 to 60 min before radiotherapy each Monday, Wednesday, and Friday to 34 g/m2 in 17 doses) in patients with unresectable head and neck carcinomas. A recent analysis showed only 14.7% grade 1 and 3.9% Grade 2 peripheral neuropathy. In the initial study design, 133 evaluable patients per treatment arm could achieve an 80% level of power of detecting a 15% difference in local-regional control rates between the radiotherapy arm (25% local-regional control at 2 years) and the radiotherapy plus etanidazole arm (assuming a 40% rate). Allowing for 20 ineligible cases in each arm, a total number of 306 was required. An interim analysis showed that 27% of the patients assigned to radiotherapy plus etanidazole are receiving less than 14 doses of the drug. It is assumed that less than 14 drug doses will not produce any therapeutic gain, therefore, a true 40% local-regional control rate in the radiotherapy plus etanidazole arm will be observed as a 36% rate when analyzed by assigned treatment. Using this information, the study was modified to have an 80% level of power in detecting a difference between a 25% local-regional control rate in the radiotherapy group and a 36% rate in the radiotherapy plus etanidazole group. Allowing for a 10% patient ineligibility rate, 518 patients are required. With 12 patients entered per month, it is estimated that patient accrual to this study will continue through October 1991.

Carcinoma, Squamous Cell↗
PubMed1992

Distribution of etanidazole into human brain tumors: implications for treating high grade gliomas.

Etanidazole was developed as an oxygen-mimetic radiosensitizer less lipophilic than misonidazole. Sensitization depends on an adequate concentration of drug in the tumor at the time of irradiation. Therefore, due to the presence of the blood-brain barrier, brain tumors may theoretically be difficult to radiosensitize due to the hydrophilic characteristics of etanidazole. Based on previous reports of loss of BBB integrity in brain tumors, we investigated the ability of etanidazole to penetrate into malignant gliomas of patients receiving etanidazole as part of a Phase I continuous infusion protocol. The patients had completed previous external beam irradiation. Twenty-two patients were studied and their etanidazole plasma and biopsy data were compared to the 2-compartment model derived from a second group of 19 patients with bolus etanidazole. Etanidazole concentration in brain tumor biopsies varied widely and appeared to be clustered into a higher and a lower pharmacokinetic group having mean tumor to well-perfused second compartment ratios of 1 and 0.25, respectively. Both high and low etanidazole concentrations were evident in different biopsies obtained from the same patient. Correlations between histology and tissue concentrations suggested that the higher level correspond to malignant tissue. These data indicate that the blood brain barrier is disrupted to varying degrees by the brain tumor and/or prior irradiation and that etanidazole penetrates into brain tumors.

Brain Neoplasms↗
PubMed1992

Final report of the phase I trial of continuous infusion etanidazole (SR 2508): a Radiation Therapy Oncology Group study.

Seventy-eight patients have been treated on a Phase I trial using continuous infusion etanidazole while undergoing brachytherapy for locally advanced tumors. There were two sequential schemata, the first treated 63 patients with doses ranging from 8-23 g/m2 over 48 hr and the second treated 15 patients with doses ranging from 20-23 g/m2 over 96 hr. The tumor sites were: brain (n = 42), cervix (n = 22), and breast (n = 14). Patients received a loading dose of etanidazole of 2 g/m2 followed by a continuous infusion for a total of 48 or 96 hr while radioactive implants were in place. Of the 63 patients in the 48-hr study, 52 were entered at doses of less than or equal to 21 g/m2 and there were no definite neuropathies but two patients with the cramping/arthralgia syndrome. Of the 11 patients entered at 22-23 g/m2, 1 patient had symptoms of peripheral neuropathy (Grade II) and 6 had the cramping/arthralgia syndrome. This is a new syndrome, distinct from the peripheral neuropathy, characterized by transient alterations in sensations consisting of cramping, arthralgias, or tingling that resolved completely at intervals varying from a few hours to about 1 week post-treatment. The cramping/arthralgia syndrome limited dose escalation; therefore, the maximum tolerated dose over 48 hr was determined to be 20-21 g/m2. The 96-hr infusion was limited to patients with recurrent gliomas undergoing stereotactic implantation. To date, 15 patients have been treated with doses of 20-23 g/m2. No toxicity was encountered at doses less than or equal to 22 g/m2. At 23 g/m2, one patient developed Grade III neuropathy and three patients had mild cramping/arthralgia syndrome, for whom the drug was discontinued. Therefore, it appears the maximum tolerated dose at 96 hr will be approximately 23 g/m2, which is 10-15% higher than for the 48-hr infusion.

Brachytherapy↗
PubMed1992

Role of additional radiotherapy in advanced stages of Hodgkin's disease.

Although radiotherapy is widely used as additional treatment following chemotherapy, its precise role has never been clearly proven. Relapses tend to occur in previously involved bulky sites. Non-randomized studies may suggest a positive effect of the addition of radiotherapy. This effect however, might also be caused by selection. Randomized studies have not resulted in a survival advantage for the patients treated with additional radiotherapy compared to no further treatment or additional chemotherapy. The SWOG study 7808 suggest a 20% benefit in remission duration for the nodular sclerosis histology subgroup. Definitive conclusions have to wait for more mature results of randomized studies including the ongoing EORTC study and the possibility to perform an overview of all studies.

Antineoplastic Combined Chemotherapy Protocols↗