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Biomedical subjects

R R Weichselbaum

Publications and source records attributed to R R Weichselbaum.

At least 235 records · Page 13Linked to original sources
PubMed1988

Concomitant hydroxyurea, 5-fluorouracil, and radiation therapy for recurrent head and neck cancer: early results.

We tested the combination of hydroxyurea (HU), 5-fluorouracil (5-FU), and concomitant radiotherapy (XRT) in a group of patients with advanced or recurrent head and neck cancer. Both drugs are effective single agents, have shown synergistic activity in vitro, and can act as radiation sensitizers. A 5-day course of radiotherapy, with simultaneous HU and continuous infusion 5-FU, was followed by a 9-day rest period; cycles were repeated until completion of XRT. Sixteen patients have completed their therapy. Eleven patients had recurrent disease after previous therapy with surgery (11 patients), radiotherapy (9 patients), and combination chemotherapy (4 patients). Five patients had not received previous local therapy. These patients had persistent disease after induction chemotherapy and/or were inoperable because of poor general medical condition. Of 15 patients evaluable for response, 9 had complete response, including 5 patients who had earlier local therapy; 5 had partial response; and 1 failed to respond. Toxicities included mild myelosuppression and mucositis. No unusual complication related to previous radiotherapy was observed. This regimen has shown impressive activity in a cohort of patients who are not usually responsive to other types of currently available therapy. We are continuing our investigation to further define efficacy, toxicity, and maximally tolerated doses of this regimen.

Aged↗
PubMed1988

Cisplatin, fluorouracil, and high-dose leucovorin for recurrent or metastatic head and neck cancer.

We added high-dose oral leucovorin to the combination of cisplatin and fluorouracil (5-FU) to assess the efficacy of this regimen in the treatment of patients with head and neck cancer. Cisplatin, 100 mg/m2, was followed by a 5-FU continuous infusion at 600 mg/m2/d for five days. Leucovorin, 50 mg/m2, was administered at the start of cisplatin and every six hours throughout the duration of the 5-FU infusion. The dose of 5-FU was escalated to 800 mg/m2 and 1,000 mg/m2 according to observed toxicity. In a second phase of the study, the dose of leucovorin was escalated to 50 mg/m2 every four hours. A total of 25 patients were registered: 23 had recurrent disease after extensive prior treatment; and two had newly diagnosed metastatic disease. The maximally tolerated dose of 5-FU was 800 mg/m2/d with leucovorin administered every six hours. Toxicities at that level included mild to moderate myelosuppression and dose-limiting mucositis in the previously irradiated field. Identical toxicities were observed when administering 800 mg/m2/d of 5-FU with leucovorin every four hours. Eighteen patients were evaluated for response: one had a pathologic complete response; nine had a partial response (including four who received prior cisplatin and 5-FU as induction chemotherapy); and eight patients failed to respond. The mean peak and trough plasma leucovorin concentrations were 2.61 (+/- 1.07) mumol/L and 2.46 (+/- 0.95) mumol/L with administration of the drug every six hours, and 2.75 (+/- 2.15) mumol/L and 2.52 (+/- 1.48) mumol/L with administration every four hours. We conclude that the combination of cisplatin, 5-FU, and leucovorin has activity in the treatment of recurrent head and neck cancer. The maximally tolerated dose of 5-FU in this study was 800 mg/m2/d, with mucositis in previously irradiated sites being dose-limiting. Plasma leucovorin concentrations exceeding 1 mumol/L are achieved following oral administration of this drug.

Adult↗
PubMed1988

A link between calcitriol and bone resorption.

Calcitriol exposure stimulated a human osteosarcoma cell line, U2-OS, to produce a factor(s) which stimulated bone degradation in human monocyte cultures and osteoclastic bone resorption in fetal rat long bone cultures. The factor(s) was elicited by as little as 10(-10) M calcitriol. The factor is effective in stimulating peripheral blood monocytes to degrade bone, suggesting a direct effect on cellular bone breakdown. The fetal long bone assays suggest that the osteoblast-like cells produce a factor(s) which stimulates osteoclasts. This is confirmed by the fact that human calcitonin added to the long bone cultures blocks the stimulation. The effect of PTH appears to be through the production of factors which stimulate osteoblasts. The present study suggests that a similar factor(s) may be responsible for the effect of calcitriol on bone resorption.

Bone Resorption↗
PubMed1988

Treatment selection in T1 and T2 vocal cord carcinoma.

Radiation therapy is the treatment of choice for most patients with T1 and T2 carcinomas of the vocal cord, resulting in high rates of local control and preservation of voice. Though surgical options also result in high rates of local control, vocal quality is inferior. Endoscopic laser surgery has been used only on small numbers of selected T1 lesions. Its role needs to be defined as vocal quality tends to be inferior to radiation therapy and substantial numbers of patients require additional treatment.

Combined Modality Therapy↗
PubMed1988

Sequential administration of methotrexate, cisplatin, and 5-fluorouracil in multimodal therapy for locally advanced head and neck cancer.

Thirty-eight previously untreated patients with locally advanced head and neck cancer received three cycles of induction chemotherapy with methotrexate (120 mg/m2) followed by cisplatin (100 mg/m2) and a 5-day continuous infusion of 5-fluorouracil (1,000 mg/m2 per day). The response rate in 34 evaluable patients was 94%, with a complete response rate of 26%. Thirty-one patients underwent local therapy following induction chemotherapy, and 25 (81%) were rendered free of disease: 14 of 15 treated with surgery and radiotherapy and 11 of 16 treated with radiotherapy alone. At a median follow-up of 11 months, 8 patients have relapsed while the remaining 17 patients continue free of disease. The dose-limiting toxicity of chemotherapy was mucositis resulting in reduction of the 5-fluorouracil dose in 28 patients. This regimen is highly effective in inducing responses in patients with locally advanced head and neck cancer; 81% of the patients who complete local therapy are rendered free of disease with this multimodal approach. Due to short follow-up, the relapse rate, overall survival, and disease-free survival cannot yet be determined.

Adolescent↗
PubMed1987

The raf oncogene is associated with a radiation-resistant human laryngeal cancer.

In order to identify the genetic factors associated with the radiation-resistant human laryngeal carcinoma cell line (SQ-20B), tumor cell DNA was transfected into NIH/3T3 cells. A high incidence (six out of six) of raf sequences was found in transfected NIH/3T3 clones and the tumorigenic potential of SQ-20B DNA could be linked to genomic fragments that represent most of the kinase domain of human c-raf-1. An apparently unaltered 3.5-kilobase pair (kb) human c-raf transcript was identified in SQ-20B cells but was not observed in the transfected NIH/3T3 cell clones. Two new transcripts (4.2 kb and 2.6 kb) were found in tumorigenic clones; the large transcript was missing in a very poorly tumorigenic clone. Cytogenetic analysis indicated that the normal autosomes of chromosome 3 were absent in SQ-20B karyotypes and had formed apparently stable marker chromosomes. Unlike the recipient NIH/3T3 cell line, 30 percent of the transformed clone-1 metaphases had minute and double-minute chromosomes representative of amplified DNA sequences. The frequency of the c-raf-1 identification by NIH/3T3 transfection of SQ-20B DNA suggests the presence of some genetic abnormality within this locus.

Animals↗
PubMed1987

Expression and methylation of the Blym gene in human tumor cell lines.

We have examined Blym expression in 11 human tumor cell lines. Increased Blym expression was observed in one of three osteosarcoma cell lines relative to nontransformed human foreskin fibroblasts. In addition, enhanced Blym expression was observed in a melanoma cell line and in 2 of 6 squamous carcinoma cell lines relative to nontransformed, low passage human epithelial cells. We found no evidence of gene amplification or rearrangements of Blym sequences in any of the cell lines we have examined. We further analyzed the state of methylation of the Blym gene in several of the tumor cell lines by Msp I/Hpa 11 restriction endonuclease digestion. All cell lines examined had similar Msp I digestion patterns. However, the different tumor cell lines had different Hpa 11 digestion patterns. Therefore, our results indicate that the Blym gene is differentially expressed and methylated in human tumor cell lines.

Cell Line↗
PubMed1987

The maximum recovery potential of human tumor cells may predict clinical outcome in radiotherapy.

We studied inherent radiosensitivity/resistance (D0), ability to accumulate sublethal damage (n) and repair of potentially lethal damage (PLDR) in established human tumor cell lines as well as early passage human tumor cell lines derived from patients with known outcome following radiotherapy. Survival 24 hrs after treatment of human tumor cells with X rays in plateau phase cultures is a function of initial damage (D0, n), as well as recovery over 24 hrs (PLDR). A surviving fraction greater than .1 24 hrs following treatment with 7 Gy in plateau phase cultures is associated with tumor cell types (melanoma, osteosarcoma) with a high probability of radiotherapy failure or tumor cells derived from patients who actually failed radiotherapy. Therefore, total cellular recovery following radiation may be an important determinant or radiocurability. Accurate assays of radiotherapy outcome may need to account for all these radiobiological parameters.

Cell Line↗
PubMed1987

Platinum complexes inhibit repair of potentially lethal damage following bleomycin treatment.

The SCC-25 cell line is a well-established line derived from a human squamous carcinoma of the head and neck. The capacity of this cell line for recovery from potentially lethal damage following X-ray treatment has been documented. The survival curve of stationary phase SCC-25 cells exposed to various concentrations of bleomycin is biphasic with an initial sensitive phase and a less sensitive second phase as is common for many cell lines. Stationary phase SCC-25 cells were exposed to 100 mU ml-1 of bleomycin for 1 h. The drug was removed and the cells were allowed various periods to recover from potentially lethal damage. After 24 h, the SCC-25 cells showed a recovery ratio (R/R0) of 7.0 which corresponded to an immediate survival at a drug level of 27 mU ml-1, a dose 3.7-fold less than the exposure concentration of 100 mU ml-1. Over the course of the first 4 h following bleomycin exposure, 0.5 microM CDDP was a very effective inhibitor of potentially lethal damage repair, giving a R/R0 of 1.1 or nearly complete inhibition of recovery. Between 2 and 4 h the R/R0 was 1.6-1.8 with CDDP and 4.1-5.3 without CDDP indicating appreciable inhibition of recovery. Plant (10 microM) and Plato (10 microM) produced potentially lethal damage recovery inhibition patterns very similar to that of CDDP. After 1 h the recovery ratios in the presence of Plant and Plato were 1.1-1.3. Between 2 and 4 h, Plato and Plant gave recovery ratios of 1.8-2.3 and 1.6-1.9, respectively. NIPt and Pt(terpy) were examined at both 10 microM and 25 microM for their ability to inhibit potentially lethal damage recovery after bleomycin treatment. After 1 h, NIPt gave a recovery ratio of 1.3-1.4, and after 2-4 h the recovery ratio was 1.7-2.6. Pt(terpy) gave recovery ratios of 1.3-1.6 after 1 h and 1.5-1.8 after 24 h.

Bleomycin↗
PubMed1987

An analysis of induction and adjuvant chemotherapy in the multidisciplinary treatment of squamous-cell carcinoma of the head and neck.

This study examines the role of combination chemotherapy with surgery and/or radiotherapy in the initial treatment of patients with advanced stage III and IV squamous-cell carcinoma of the head and neck (SCCHN). Two courses of initial (induction) cisplatin, bleomycin, and methotrexate with oral calcium leucovorin (PBM) were used with the principal intent of increasing the effectiveness of subsequent surgery and/or radiotherapy. Following induction chemotherapy and local treatment, disease-free patients who had responded to initial chemotherapy were entered into a randomized trial of adjuvant PBM. The response rates to induction PBM chemotherapy were a complete response (CR) rate of 26% and a partial response (PR) rate of 52%, for an overall response rate of 78%. A response to induction PBM was highly correlated with failure-free survival (P less than .0001). A Cox multistep regression analysis of potential prognostic factors was performed. After adjusting for the significant prognostic factors of performance status, initial tumor size, and primary tumor site, a response to induction chemotherapy remained independently associated with improved survival (P = .0002). The randomized trial of adjuvant chemotherapy demonstrated that such treatment significantly improved failure-free survival by decreasing local-regional failures. The benefit of adjuvant chemotherapy was particularly evident in patients who had a PR to induction chemotherapy (P = .01). The toxicity of this multidisciplinary approach was predictable and acceptable. Surgery and radiotherapy were not compromised by induction or adjuvant chemotherapy. Definitive evidence that chemotherapy can favorably influence survival awaits confirmation of these results by a randomized trial using a control arm of patients treated with conventional surgery and/or radiotherapy alone.

Aged↗
PubMed1987

Recovery from sublethal and potentially lethal damage in an X-ray-sensitive CHO cell.

It has been suggested that DNA strand breaks are the molecular lesions responsible for radiation-induced lethality and that their repair is the basis for the recovery of irradiated cells from sublethal and potentially lethal damage. EM9 is a Chinese hamster ovary cell line that is hypersensitive to killing by X rays and has been reported to have a defect in the rate of rejoining of DNA single-strand breaks. To establish the importance of DNA strand-break repair in cellular recovery from sublethal and potentially lethal X-ray damage, those two parameters, recovery from sublethal and potentially lethal damage, were studied in EM9 cells as well as in EM9's parental repair-proficient strain, AA8. As previously reported, EM9 is the more radiosensitive cell line, having a D0 of 0.98 Gy compared to a D0 of 1.56 Gy for AA8 cells. DNA alkaline elution studies suggest that EM9 cells repair DNA single-strand breaks at a slower rate than AA8 cells. Neutral elution analysis suggests that EM9 cells also repair DNA double-strand breaks more slowly than AA8 cells. All of these data are consistent with the hypothesis that DNA strand-break ligation is defective in EM9 cells and that this defect accounts for increased radiosensitivity. The kinetics and magnitude of recovery from sublethal and potentially lethal damage, however, were similar for both EM9 and AA8 cells. Six-hour recovery ratios for sublethal damage repair were found to be 2.47 for AA8 cells and 1.31 for EM9 cells. Twenty-four-hour recovery ratios for potentially lethal damage repair were 3.2 for AA8 and 3.3 for EM9 cells. Both measurements were made at approximately equitoxic doses. Thus, the defect in EM9 cells that confers radiosensitivity and affects DNA strand-break rejoining does not affect sublethal damage repair or potentially lethal damage repair.

Animals↗
PubMed1986

The syndrome of inappropriate antidiuretic hormone secretion associated with induction chemotherapy for squamous cell carcinoma of the head and neck.

Two patients with squamous cell carcinoma of the head and neck are reported in whom the syndrome of inappropriate antidiuretic hormone (SIADH) secretion occurred transiently during the rapid cytolytic phase of tumor destruction after chemotherapy with cis-platinum diamminedichloride and bleomycin. Immunoperoxidase staining for ADH of the original biopsy specimens from both patients was negative. Possible mechanisms for and the implications of the production of SIADH in this setting are discussed.

Antineoplastic Agents↗
PubMed1986

Radioresistant and repair proficient cells may determine radiocurability in human tumors.

Radiosensitivity and repair of radiation damage was studied in 29 human tumor cell lines. Nine tumor lines appeared radioresistant (RAD+) and were associated with radioincurable tumors. When the ability to repair potentially lethal damage was studied in plateau phase cultures, some tumor cell lines derived from radioincurable tumors were more efficient in this process (PLDR+). The results suggest that the presence of radioresistant or repair proficient cells may be responsible for local failure following radiotherapy. Advancements in cell culture and molecular biology may lead to predictive assays useful to clinicians.

Cell Line↗
PubMed1986

Radiation-resistant and repair-proficient human tumor cells may be associated with radiotherapy failure in head- and neck-cancer patients.

Inherent cellular radioresistance and repair of x-ray damage was studied in 19 early-passage squamous cell carcinoma lines derived from head- and neck-cancer patients with known clinical results following radiotherapy. Human tumor cells that were radioresistant and/or proficient in accumulation/repair of x-ray damage were cultured from patients unsuccessfully treated with radiotherapy. Thus, the presence of radiation-resistant and repair-proficient tumor cells was associated with clinical radiation failure, suggesting the possibility of a predictive assay based on in vitro radiobiological parameters.

Carcinoma, Squamous Cell↗
PubMed1986

Fibroblast radiosensitivity and intraocular fibrovascular proliferation following radiotherapy for bilateral retinoblastoma.

A 5-day-old female patient was found to have large hereditary retinoblastomas in the posterior pole of each eye. The patient received radiation treatment over a 39-day period, with each retina receiving 4600 rad. Two weeks after the complete treatment the tumours had regressed to approximately one-quarter of their original size. By 14 weeks following completion of radiotherapy the patient had developed in each eye extensive iris neovascularisation with progressive closure of the filtration angles, secondary glaucoma, and retinal detachments resulting from fibrovascular proliferation on the retinal surface. Radiosensitivity studies were from separate conjunctival biopsies obtained before and after radiation. These showed a D0 (calculated survival curve parameters, defined in the Methods section) in the exponential growth phase of 110 prior to radiation and a postirradiation exponential growth phase D0 of 70. Karotype studies showed several chromosomal abnormalities following radiotherapy. The clinical course and pathology findings are thought to represent an unusually severe orbital and ocular response to radiation therapy. These findings are consistent with our hypothesis that some patients with hereditary retinoblastoma may have a defect in the accumulation repair of x-irradiation induced DNA damage.

Cell Survival↗
PubMed1985

Combined modality treatment of head and neck cancer with cisplatin, bleomycin, methotrexate-leucovorin chemotherapy.

The multidisciplinary treatment results of 114 patients with advanced, untreated Stage III and IV squamous cell carcinoma of the head and neck region are reported. Induction chemotherapy with two cycles of cisplatin 20 mg/m2/day intravenous bolus days 1 through 5, bleomycin 10 mg/m2/day as a continuous infusion days 3 through 7, and methotrexate 200 mg/m2 intravenous bolus on days 15 and 22 with leucovorin rescue was utilized before definitive surgery and/or radiation therapy. The total response rate was 78% with 30 (26%) patients achieving complete response and 59 (52%) patients achieving partial response. Patient age, performance status, histologic grade of tumor, and tumor site did not predict response to chemotherapy. Induction chemotherapy was well tolerated with myelosuppression and nephrotoxicity being dose-limiting in a few patients. The toxicity of subsequent local treatment with surgery and/or radiation is reported with an analysis of local treatment failures. A strong correlation was noted between local control of tumor and postchemotherapy tumor size before local treatment.

Adult↗
PubMed1985

Antipain-mediated suppression of sister chromatid exchanges induced by an inhibitor of poly (ADP-ribose) polymerase.

Exposure of mammalian cells to inhibitors of poly(ADP-ribose) polymerase, such as 3-aminobenzamide (3AB) results in the induction of sister chromatid exchanges (SCEs). The mechanism for the induction of SCEs by 3AB is unknown but is thought to be related to the incorporated halogenated pyrimidine used in SCE analysis. In this characteristic, 3AB-mediated SCE induction is similar to the elevated SCE frequency found in Bloom's syndrome (BS) cells. Recently, it has been reported that certain protease inhibitors, such as antipain, will inhibit SCE induction in BS cells. We now report that antipain will also suppress 3AB-induced SCE frequency. As has been reported for BS cells, the effects of antipain on SCE induction are partial, reducing SCE frequency by 0.15 to 0.40 SCE/chromosome (5-25% of the total induced frequency), and 30 microM concentrations of antipain are saturating. Antipain has no effect on baseline SCE frequency. These effects appear to involve free-radical production because dimethylsulfoxide (DMSO), a free-radical scavenger, will mimic the effects of antipain on 3AB-induced SCEs. Both antipain and DMSO will also reduce the elevated SCE frequency found in cells exposed to high (100 microM or more) levels of bromodeoxyuridine (BrdUrd). High exogenous levels of BrdUrd produce some of the same biological effects as 3AB exposure. Thus, a minor fraction of the elevated SCE frequency seen in cells exposed to 3AB or to high levels of BrdUrd appears to be similar to that found in cultured BS cells and is probably due to some free-radical-producing process.

Animals↗