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Biomedical subjects

R Munden

Publications and source records attributed to R Munden.

8 recordsLinked to original sources
PubMed2003

Radiotherapy patterns of care study in lung carcinoma.

PURPOSE: For the first time, a lung Patterns of Care Study was conducted to determine the national patterns of radiation (RT) practice in patients treated for nonmetastatic lung cancer in 1998 to 1999. MATERIALS AND METHODS: A national survey of randomly selected RT institutions in the United States was conducted using two-stage cluster sampling, stratified by practice type. Patients with nonmetastatic lung cancer (Karnofsky performance score [KPS] > or = 60), who received RT as definitive or adjuvant therapy, were randomly selected. To determine national estimates, sample size was weighted by the relative number of institutions per strata and the number of patient records reviewed per the number of patients eligible. Accordingly, 42,335 patient records from 58 institutions were reviewed by trained research associates. The unweighted sample size (or number of patients) was 541. RESULTS: The histologies were small-cell lung cancer (SCLC) in 14.5% of patients versus non-small-cell lung cancer (NSCLC) in 85.5% of patients. The median age was 67 years (range, 29 to 92 years); 61% of patients were male, and 38% were current smokers. Bone scans and brain imaging were not obtained in 34% and 52% of clinical stage (CS) III NSCLC patients, respectively. Regarding treatment strategies, for SCLC and CS III NSCLC, chemotherapy plus RT was used significantly more than RT alone (P <.05); in CS I NSCLC, RT alone was the primary treatment (P <.05). Overall, 58% of patients received systemic therapy. On multivariate analysis, factors correlating with increased use of chemotherapy included younger age, histology (SCLC > NSCLC), increasing CS, increasing KPS, and lack of comorbidities. Only 3% of all patients were treated on prospective clinical trials. CONCLUSION: This study establishes the general patterns of care for lung carcinoma in RT facilities within the United States. As supported by clinical trials, patients with limited-stage SCLC and CS III NSCLC received chemotherapy plus RT more than they received RT alone. Further improvements in staging, smoking cessation, and increased accrual to clinical trials must be encouraged.

Adult↗
PubMed2001

Multi-institutional phase I/II trial of oral bexarotene in combination with cisplatin and vinorelbine in previously untreated patients with advanced non-small-cell lung cancer.

PURPOSE: Bexarotene (Targretin; Ligand Pharmaceuticals, Inc, San Diego, CA) is a retinoid-X-receptor (RXR)-selective retinoid with preclinical antitumor activity in squamous cell cancers. In this phase I/II trial, we combined bexarotene with cisplatin and vinorelbine in the treatment of patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Forty-three patients who had stage IIIB NSCLC with pleural effusion or stage IV NSCLC and had received no prior therapy received bexarotene in combination with cisplatin (100 mg/m2) and vinorelbine (alternating doses of 30 mg/m2 and 15 mg/m2). In the phase I portion, the daily dose of bexarotene was escalated in cohorts of three patients from 150 mg/m2 to 600 mg/m2, beginning 1 week before the start of the cisplatin-vinorelbine regimen. Once the maximum-tolerated dose (MTD) of bexarotene was determined, the study entered the phase II portion. Response rate was the primary end point; median survival time and 1-year survival rate were secondary end points. RESULTS: In the phase I portion, the daily MTD of bexarotene was determined to be 400 mg/m2. Eight of 43 patients exhibited major responses. Seven (25%) of the 28 patients in the phase II portion responded to treatment. The median survival time in the phase II portion was 14 months; nine (32%) of the 28 patients were still alive at a minimum follow-up of 2 years. One-year and projected 3-year survival rates were 61% and 30%, respectively. The most common grade 3 and 4 adverse events were hyperlipemia, leukopenia, nausea, vomiting, pneumonia, dyspnea, anemia, and asthenia. Grade 3 and 4 laboratory abnormalities with incidences greater than 5% were decreased hemoglobin levels and WBC, absolute neutrophil, and absolute lymphocyte counts and increased prothrombin time and creatinine and amylase levels. Of the two cases of pancreatitis, one required hospitalization and both were associated with increased triglyceride levels. There was one death secondary to renal insufficiency unrelated to bexarotene treatment. CONCLUSION: In patients with advanced NSCLC, bexarotene with cisplatin and vinorelbine yielded acceptable phase II response rates (25%) and was associated with better-than-expected survival (14-month median survival time; 61% 1-year, 32% 2-year, and 30% projected 3-year survival rates). The regimen should be studied in larger clinical trials.

Administration, Oral↗
PubMed2000

Thoracicrad.org.

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PubMed1993

Voltammetric study of salbutamol and application to its determination in a tablet dosage form and dissolution profiles for the dosage form.

The oxidative voltammetric behaviour of salbutamol at a glassy carbon electrode surface has been studied using cyclic voltammetry and differential pulse voltammetry. Oxidation of the drug was effected in a single irreversible, adsorption-controlled step in phosphate buffer. The process was found to be dependent on the ionic strength and the pH of the supporting electrolyte. The response was evaluated with respect to accumulation time, scan rate and other variables. Using differential pulse voltammetry following electrochemical pretreatment of the electrode surface, the drug yielded a well-defined voltammetric response in phosphate buffer, pH 5.0, at +0.75 V (vs SCE). This process could be used to determine salbutamol concentrations in the range 8 x 10(-7) M to 8 x 10(-5) M with a detection limit of 2 x 10(-7) M. The method was applied, without any interferences from the excipients, to the determination of the drug in a tablet dosage form and in drug dissolution studies. The absolute recovery for salbutamol was greater than 95% at the concentration levels studied, and reproducible voltammetric signals were obtained with a relative standard deviation of 2.4% for n = 7 at a concentration level of 8 x 10(-5) M.

Adsorption↗
PubMed1993

Cystic pheochromocytoma: radiologic diagnosis.

Cystic pheochromocytomas are unusual variants of adrenal pheochromocytomas. Computed tomography and pathologic findings in the two cases reported here illustrate three cardinal principles in the diagnosis of cystic pheochromocytomas: (1) A suprarenal cystic tumor discovered on CT may be the result of hemorrhage and necrosis of an adrenal pheochromocytoma. (2) The cystic pheochromocytoma typically exhibits areas of low attenuation, with Hounsfield units in the range of 5 to 15 and rim enhancement on contrast administration. (3) Incidental adrenal lesions with these features discovered on CT scanning are an indication for catecholamine assays to screen for pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1992

Differential pulse voltammetric determination of sumatriptan succinate (1:1) in a tablet dosage form.

A voltammetric study of the oxidation of sumatriptan succinate (1:1) has been carried out at the glassy carbon electrode. This compound exhibited a single wave in Britton-Robinson buffer solutions of pH 2-11, with a maximum current at pH 5.0. The mechanism of oxidation was shown to be due to oxidation of the N-H group in the indole ring. Based on this study, a simple, rapid and sensitive voltammetric method was developed for the determination of the drug in a tablet dosage form.

Electrochemistry↗
PubMedDate not supplied

Coronary artery dosimetry in intact left breast irradiation.

PURPOSE: The purpose of this article is to report dose-volume histograms of coronary vessels from irradiation of the intact left breast. PATIENTS AND METHODS: Fifteen women with cancer of the left breast underwent computed tomographic treatment planning for radiation treatments of an intact left breast. Images through the heart were reconstructed at 1-mm increments to permit contouring of the coronary vessels. Five treatment plans were created for each patient; one plan from the simulated treatment fields and four additional plans that were generated from virtual treatment fields created by shifting the isocenter 5 mm and 10 mm both superficially and deep. The radiation dose was calculated using a three-dimensional treatment planning system that incorporated heterogeneity correction factors. RESULTS: With no adjustment to the perpendicular lung distance, a mean volume of 12% of the left anterior descending coronary artery received 20 Gy, 6% received 30 Gy, and 3% received 40 Gy. The dose to the left anterior descending coronary artery varied significantly with changes in the perpendicular lung distance. From the mean perpendicular lung distance of 1.87 for the simulated fields, a 5-mm increase in the perpendicular lung distance resulted in an increase of 20%, 15%, and 12% in the percentage of the left anterior descending coronary artery treated to 20 Gy, 30 Gy, and 40 Gy, respectively. With a 10-mm increase, the respective volumes were increased to 49%, 41%, and 34%, respectively. A 5-mm reduction of lung distance in the original plan resulted in a decrease of 10%, 5%, and 3% in the percentage treated to 20 Gy, 30 Gy, and 40 Gy, respectively. The dose to the left main coronary artery, the right main coronary artery, and the left circumflex coronary artery was limited to scatter and was less than 7 Gy. Changes in the perpendicular lung distance did not significantly affect the dose administered to these vessels. DISCUSSION: The left anterior descending coronary artery is anatomically located at the edge of the cardiac silhouette on traditional treatment films. Small changes in the perpendicular lung distance can significantly change the dose delivered to this vessel. A fundamental change in the shape of the dose-volume histogram occurs at a perpendicular lung distance of 2.3 cm, whereas the dose is very low when the perpendicular lung distance is less than 1.3 cm. These points may serve as clinically important values in the treatment planning for cancer of an intact breast.

Arteries↗