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Biomedical subjects

A M Mauer

Publications and source records attributed to A M Mauer.

At least 19 recordsLinked to original sources
PubMed2000

Lung cancer.

Lung cancer remains a major worldwide health problem, accounting for more than a sixth of cancer deaths. The proportion of cancers that are adenocarcinomas is increasing in North America and to some degree in Europe, leading to a changing clinical picture characterised by early development of metastases. Newer diagnostic techniques have allowed for more accurate tumour staging and treatment planning. In patients with non-small-cell cancer, surgical resection offers substantial cure rates in early-stage cases. Combined chemotherapy plus radiation therapy has clearly improved the treatment results for patients with locally advanced cancers, and patients with metastatic disease are now candidates for newer chemotherapy regimens with more favourable results than in the past. Small-cell lung cancer is highly responsive to chemotherapy, and recent advances in radiation therapy have improved the prospects for long survival. New techniques for screening, and innovative approaches to both local and systemic treatment offer hope for substantial progress against this disease in the near future.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Therapeutic plasma exchange for the acute management of the catastrophic antiphospholipid syndrome: beta(2)-glycoprotein I antibodies as a marker of response to therapy.

We describe two patients with the catastrophic antiphospholipid syndrome associated with elevation of beta(2)-glycoprotein I antibodies and fulminant thrombotic diatheses. Both patients were treated with therapeutic plasma exchange (TPE), which resulted in a marked decrease in antibody titer accompanied by an improved clinical outcome in one patient (IgG antibody). In the second patient, the outcome was poor despite TPE (IgA antibody). There were no significant complications of TPE in either case. Because of the fulminant nature of the catastrophic antiphospholipid syndrome, we conclude that a trial of TPE is warranted for the acute management. Further studies are needed to clarify which patients may benefit from this treatment.

Amputation, Surgical↗
PubMed1999

First two cases of immune hemolytic anemia associated with ceftizoxime.

BACKGROUND: Second- and third-generation cephalosporins have been associated with immune-mediated hemolytic reactions. This report discusses two patients who developed clinically significant extravascular hemolysis while receiving the third-generation cephalosporin ceftizoxime (Ceftizox). This is believed to be the first time hemolysis has been described in patients receiving this drug. STUDY DESIGN AND METHODS: Immunologic workup of drug-dependent antibodies was performed on blood samples using drug-coated and immune complex methodologies. Antibody classes and titers were analyzed. RESULTS: Both the patients' sera contained anti-ceftizoxime that reacted with red cells only when ceftizoxime was added to the sera ("immune complex" method). The patients recovered without complications following discontinuation of the drug. Each patient had IgM and IgG drug-dependent antibodies. The drug-induced antibodies from each patient cross-reacted with cefotaxime, which is structurally similar to ceftizoxime, but cross-reacted either weakly or not at all with ceftriaxone, which has a more complex side chain. CONCLUSION: This report describes the first cases of immune hemolytic anemia associated with ceftizoxime. In drug-induced hemolytic reactions, prompt recognition and discontinuation of the drug may be important factors in reducing the chance of serious sequelae.

Adult↗
PubMed1998

A phase I-II study of paclitaxel, ifosfamide, and vinorelbine with filgrastim (rhG-CSF) support in advanced non-small-cell lung cancer.

PURPOSE: We designed a phase I-II trial of three active agents, paclitaxel, ifosfamide, and vinorelbine, in advanced non-small-cell lung cancer (NSCLC) to: 1) define the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of paclitaxel with filgrastim (G-CSF) support; and 2) determine the overall response rate and median survival of patients treated on this regimen. PATIENTS AND METHODS: We treated cohorts of patients with stage IIIB or IV NSCLC with ifosfamide 1.2-1.6 g/m2/day x 3 and vinorelbine 20-25 mg/m2/day x 3 and escalating doses of paclitaxel at 100-175 mg/m2 on day 2 with G-CSF support on a 21-day cycle. One prior experimental single-agent chemotherapy regimen was allowed. RESULTS: Fifty-six patients, were enrolled on this trial: 27 on the phase I portion of the study and an additional 29 at the recommended phase II dose (RPTD). Thirteen patients had received prior chemotherapy. Paclitaxel doses of 175 mg/m2 and 150 mg/m2 produced dose-limiting myelosuppression, and the RPTD was determined to be paclitaxel 135 mg/m2 with ifosfamide 1.2 g/m2/day on days 1-3 and vinorelbine 20 mg/m2/ day on days 1-3 with G-CSF support. The overall response rate was 18%, with a median survival of 6.1 months. Six of 35 patients (17%) treated at the RPTD achieved a partial response to therapy. Grade IV neutropenia was observed in 19 of 35 patients at this dose, with eight patients suffering febrile neutropenia. CONCLUSIONS: This non-cisplatin-containing three-drug regimen has substantial toxicity and low activity in advanced NSCLC, and does not seem to improve on prior regimens. It is unclear whether the lack of efficacy relates to an antagonistic reaction between the specific drugs, administration schedule, or to subtherapeutic doses of the individual agents.

Adult↗
PubMed1998

Phase I study of docetaxel with concomitant thoracic radiation therapy.

PURPOSE: The taxanes have demonstrated activity as radiation sensitizers in preclinical studies. This study was designed to determine the maximum-tolerated dose (MTD), optimal schedule, and toxicities of docetaxel in combination with concomitant standard chest radiotherapy. PATIENTS AND METHODS: Twenty-nine patients with advanced non-small-cell lung or esophageal cancer enrolled in this phase I study to evaluate escalating docetaxel doses at three schedules. Docetaxel was administered as two 21-day cycles at doses of 40, 60, and 75 mg/m2 per cycle. Docetaxel administration schedules were as follows: schedule A, once every 3 weeks; schedule B, 2 of 3 weeks; or schedule C, weekly. Six weeks of concomitant standard chest radiotherapy in 1.8- to 2.0-Gy daily fractions was delivered to 60 Gy total. RESULTS: Dose-limiting esophagitis and neutropenia were encountered with schedules A and B at docetaxel doses of 60 mg/m2 per cycle. The docetaxel MTD for schedules A and B was 40 mg/m2 per cycle. Dose-limiting esophagitis was also observed with schedule C; however, there was no neutropenia. For schedule C, we identified the MTD as 60 mg/m2 per cycle (20 mg/m2/wk). Other toxicities encountered included thrombocytopenia, hypersensitivity reaction, and pulmonary infiltrates (fatal in two patients). Late toxicity of esophageal stricture occurred in five patients. CONCLUSION: Esophagitis and neutropenia are the dose-limiting toxicities of docetaxel administered with concomitant chest radiotherapy. Weekly administration of docetaxel allows for the highest total docetaxel dose during chest radiotherapy. We identified the recommended phase II docetaxel dose as 20 mg/m2 administered weekly with concomitant chest radiotherapy for 6 weeks.

Adult↗
PubMed1998

Ifosfamide-based three-drug combination regimens in non-small cell lung cancer.

The role of chemotherapy in the treatment of non-small cell lung cancer (NSCLC) has expanded in recent years, resulting in increased median survival and higher 5-year survival rates in some studies. Few patients with NSCLC can be cured, however, and the median survival time is still modest. Research strategies are aimed at identifying new active single agents, testing their combination in non-cisplatin- and non-carboplatin-containing regimens, and their incorporation into regimens containing more than two drugs, in efforts to improve response and survival and/or reduce toxicity. Several trials of triplet chemotherapy combinations for the treatment of NSCLC have been conducted at the University of Chicago. The three-drug regimen of vinorelbine, paclitaxel, and ifosfamide with granulocyte colony-stimulating factor was evaluated in a phase I trial. Doses of all three drugs were reduced from their standard doses so that toxicity would be manageable, although toxicity was still high. The low response rate (<20%) at the recommended phase II doses led to early closure of this trial. The University of Chicago is also assessing the three-drug combination of carboplatin, paclitaxel, and ifosfamide in patients with stage IIIB and IV NSCLC. The carboplatin and paclitaxel doses are being maintained within their active single-agent range, with the goal of identifying the maximum tolerated dose of ifosfamide when added to this combination. Additional end points include response rates, survival time, and dose-limiting toxicities. This study is ongoing.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Combined modality therapy in non-small cell lung and esophageal cancer: a phase I dose-escalation study of docetaxel with concurrent radiotherapy.

The effective treatment of non-small cell lung cancer requires both locoregional and systemic therapy. Outcome in intermediate-stage malignancies of the chest may be improved by combining chemotherapy and radiotherapy. Several combined-modality trials involving the platinum compounds, vinorelbine, gemcitabine, and the taxanes have been recently conducted. In one such phase I dose-escalation study of 29 patients with non-small cell lung cancer or esophageal cancer, the concurrent administration of docetaxel and radiotherapy at a dose of 2 Gy/d for 6 weeks was shown to be feasible. Objective tumor responses were observed, and further studies of docetaxel in combination with radiotherapy are indicated.

Adult↗
PubMed1997

Paclitaxel/carboplatin plus ifosfamide in non-small cell lung cancer.

Chemotherapy has a positive role in managing patients with stage IV non-small cell lung cancer. Randomized studies and meta-analyses comparing chemotherapy with best supportive care have confirmed a significant prolongation of survival for chemotherapy-treated patients. In recent years, several new active agents have been identified. These include the taxanes paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) and docetaxel, the antimetabolite gemcitabine, the mitotic spindle inhibitor vinorelbine, and (potentially) the topoisomerase I inhibitors. Combinations of either vinorelbine or paclitaxel with cisplatin have resulted in a significant increase in median survival times compared with both cisplatin and vindesine and cisplatin and etoposide. Paclitaxel combined with either carboplatin or ifosfamide also has been promising. Since even the best current combination regimens result in median survival times of less than 1 year, the identification of more active drugs and combinations remains a high priority. One possible strategy to identify more active regimens may be the combination of three rather than two active agents into a combination regimen. Although the three-drug regimens used in the 1980s appeared to be no more active than two-drug combinations, the advent of additional active compounds with novel mechanisms of action allows this question to be readdressed. Based on this background, we have initiated a phase I/II study of carboplatin and paclitaxel with escalating doses of ifosfamide. The study design and dosing schedule are discussed in this report.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Clinical studies of docetaxel (Taxotere) and concomitant chest therapy.

The administration of concomitant chemoradiotherapy has been shown to increase local and regional control of non-small cell lung cancer. Docetaxel (Taxotere; Rhône-Poulenc Rorer, Antony, France) has single-agent activity in non-small cell lung cancer, as well as radiation-enhancing potential in preclinical studies. Therefore, its investigation with concomitant radiotherapy in the clinical setting is justified. Since the clinical interactions of docetaxel and concomitant chest radiotherapy have not been previously described, we initiated a phase I study with the goal of determining the maximum tolerated dose of docetaxel and the optimal schedule for its administration during a standard course of radiation therapy to the chest, in addition to defining the dose-limiting toxicities of this regimen. This report describes the design and preliminary results of this study.

Antineoplastic Agents, Phytogenic↗
PubMed1995

Dosing of oral etoposide normalized for body surface area.

The objective of this clinical and pharmacological study was to determine whether any pretreatment parameters were associated with pharmacological or toxicity parameters after prolonged oral etoposide. Therefore, the relationships between patient characteristics and etoposide concentrations and hematological toxicity were evaluated. Sixty patients with advanced non-small cell lung cancer were treated with etoposide 50 mg/m2/day p.o. for 21 consecutive days and cisplatin 100 mg/m2 i.v. on day 1. Complete blood counts and etoposide plasma concentrations were obtained weekly. Etoposide was measured by high-performance liquid chromatography. The input variables were age, gender, race, weight, weight0.66, weight0.75, height, body surface area, performance status, albumin concentration; and total etoposide dose. The outcome measures were etoposide concentration; nadir values (white blood cells, neutrophils, hemoglobin, and platelets); the absolute decrease, relative decrease, and survival fraction of blood cells; and graded toxicity. No significant correlations were found in 49 fully evaluable patients between any of the input and outcome variables. Among the outcome variables, significant correlations were found between etoposide concentration and the logarithmic transformation of the nadir blood counts. If any of the input variables were significantly correlated to etoposide concentrations or toxicity variables, it would be possible to suggest another predictor variable besides body surface area. As long as treatment is not modified for etoposide concentrations, dosing of oral etoposide must still rely on estimates of body surface area.

Administration, Oral↗
PubMed1994

Cytotoxic effects of alpha- and gamma-interferon and tumor necrosis factor in human bladder tumor cell lines.

We investigated the activity of alpha-interferon (alpha-IFN), gamma-interferon (gamma-IFN) and tumor necrosis factor-alpha (TNF-alpha) in a panel of ten human bladder tumor cell lines. All cytokines were tested at concentrations of 100-10,000 U/ml in a clonogenic assay system. We found that alpha-IFN was active against five of the ten lines while gamma-IFN was only active against one line. TNF was active against five of the ten lines. Maximum synergisms were obtained between the alpha-IFN and TNF, occurring in nine of the ten cell lines. We conclude that alpha-IFN and TNF are active as single agents and synergistic when used together in vitro in human bladder tumor cell lines.

Cell Division↗
PubMed1993

Adult and childhood acute lymphocytic leukemia: are they different diseases?

Age has long been recognized as an important factor in predicting response to treatment for acute lymphocytic leukemia (ALL). Specifically, the results of treatment of childhood ALL have been far superior to the treatment of what appears to be the same disease in adults. However, from an analysis of the clinical and biological prognostic factors known to be predictive in childhood ALL, there is a striking difference in their distribution in adults with ALL. It appears that there is a special form of ALL seen in children of some populations with a peak incidence of three to seven years. This treatment responsive leukemia appears to be different clinically, biologically, and epidemiologically from adult ALL.

Adult↗
PubMed1993

Cocaine-induced platelet defects.

BACKGROUND AND PURPOSE: Numerous studies have demonstrated an association between acute cardiac events, cerebrovascular accidents, and cocaine use. The underlying mechanisms leading to these complications have not been well defined. Using various in vitro model systems, it has been reported that cocaine, up to or greater than an order of magnitude of the lethal dose, causes either inhibitory or proaggregatory effects on platelet function. METHODS: To address these reported discrepancies, we examined the effect of cocaine and its carrier on the activation and aggregation of human platelets in vitro. RESULTS: We found that cocaine inhibited platelet aggregation when platelets were challenged with ADP, collagen, or arachidonic acid. This inhibition was due to a direct effect on fibrinogen binding to the activated platelet. Cocaine also caused the dissociation of preformed platelet aggregates. At these same concentrations, cocaine did not inhibit agonist-mediated increases in cytosolic calcium or inhibit platelet shape change, suggesting that its effect on platelet aggregation was a selective process and not due to a total destruction of platelet function. Interestingly, the organization of the cytoskeleton of activated platelets, a secondary event critical to cell receptor clustering and clot retraction, was disrupted by cocaine treatment. In addition, alterations in platelet protein electrophoretic patterns were observed on preincubation of platelets with cocaine. CONCLUSIONS: We conclude that cocaine may have a direct inhibitory effect on the ability of platelets to participate in thrombus formation. The contribution of this effect as an underlying mechanism of sudden death in cocaine abusers is unknown.

Adenosine Diphosphate↗
PubMed1993

Pharmacodynamics of prolonged oral etoposide in patients with advanced non-small-cell lung cancer.

PURPOSE: This study was undertaken to investigate the pharmacodynamic relationship between etoposide drug levels on 21-day oral treatment courses and hematologic toxicities in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Thirty-two patients with stage IIIB or IV NSCLC were treated with oral etoposide 50 mg/m2/d for 21 consecutive days in combination with cisplatin 100 mg/m2 on day 1. Treatment was repeated every 28 days for up to six courses. Patients had not received previous chemotherapy and had a performance status of 0 to 2. Patients were monitored weekly while on treatment for compliance with oral etoposide and toxicity, including complete blood cell counts, and a blood sample before the daily etoposide dose (drug trough levels). Etoposide concentrations were measured in the plasma by high-performance liquid chromatography (HPLC). RESULTS: Three patients achieved a complete response (CR) and 10 patients a partial response for an objective response rate of 41% (95% confidence interval, 24% to 58%). The median survival was 4 months (range, 1 to 23). Neutropenia was dose-limiting, and two patients died of neutropenic sepsis. Pharmacodynamic correlations for drug concentrations and hematologic toxicities were available for 27 patients and a total of 76 treatment courses, and correlations were significant for graded hematologic toxicity and nadir counts of leukocytes, neutrophils, hemoglobin, and platelets. The grade of infection (77 courses) was also related to drug levels. Using data from 27 initial courses, a pharmacodynamic model was developed to estimate the nadir leukocyte or neutrophil count (WBCn, ANCn) based on the pretreatment count (WBCp, ANCp) and the etoposide concentration (Ec) as follows: WBCn = 0.35 (1 + WBCp x e-1.12 x Ec) and ANCn = 0.32 (1 + ANCp x e-2.47 x Ec). CONCLUSION: Etoposide concentrations are related to the resulting hematologic toxicities. It is possible to predict nadir counts in the first course by a pharmacodynamic model. The above equations need to be validated prospectively and may be useful in future studies of prolonged oral etoposide.

Administration, Oral↗
PubMed1992

Assessment of lumiaggregometry for research and clinical laboratories.

Platelet aggregometry is often used to help diagnose storage pool disease (SPD-reduced amounts of granule nucleotides) and release defects (abnormal release of granule nucleotides). The general assumption that normal aggregation patterns are sufficient to rule out the diagnosis of one of these disorders has been invalidated by the recent publication of two papers describing patients with clinical bleeding, prolonged bleeding times and normal aggregation patterns in spite of defective release. The lumiaggregometer provides a tool for measuring platelet release and aggregation simultaneously. This paper presents a standardized, reproducible method for the use of the lumiaggregometer based on a "standard curve". Data obtained during the development of the procedure are presented including normal ranges of release at different concentrations of agonists, release measured in intrinsic disorders as well as in patients on aspirin, and values for release relative to varying platelet counts. A monoclonal antibody (anti-p24/CD9; MAb7) which activates platelets similarly to thrombin and may be a useful reagent for distinguishing SPD and release defects is also introduced.

Adenosine Triphosphate↗