Biomedical subjects
Publications and source records attributed to M L Slevin.
Twenty patients with secondary liver tumours, predominantly from colorectal carcinoma, were treated with oral urea at a daily dose of 8 gm-2. Treatment was well tolerated without side-effects. No objective responses were seen. It is concluded that oral urea is ineffective in the treatment of liver metastases from colorectal cancer.
Kinetic analysis with probability mapping is an objective method of serial image analysis applicable to radioimmunoscintigraphy. The technique is described and subjected to clinical testing by comparing the prediction of biopsy histology from the probability map in patients coming to operation. In those with ovarian cancer undergoing second-look laparotomy after completing full courses of chemotherapy, the prediction of histology in 108 biopsy sites was 45 true positives and 38 true negatives, sensitivity 80%, specificity 73%, accuracy 77% p less than 0.001. In patients with tumors less than 2 cm diameter, 41 biopsy sites were predicted with a specificity of 78% and an accuracy of 76%, p less than 0.01. The technique is reducing the need for second-look laparotomy in patients with subclinical and subradiological disease. Such disease is suitable for intraperitoneal radioimmunotherapy.
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The localization of i.p. injected, radioiodine conjugated monoclonal antibody HMFG2 was studied in 18 patients with ovarian carcinoma. Patients were injected i.p. at time points up to 168 h before laparotomy, at which time tumor, ascites, normal tissue, and blood samples were removed and the contained radioactivity measured. In the first 10 patients, localization was compared with that of a simultaneously injected irrelevant (nonspecific) antibody (UJ13A) of the same immunoglobulin class and, in the subsequent 8 patients, with HMFG2 administered i.v. After i.p. injection, HMFG2-radioiodine was found in concentrations of 0.0001-0.0030% of the injected amount per gram in solid tumor, 0.0363-0.02560%/g in ascites, 0.0003-0.0017%/g in blood, and 0.001-0.0012%/g in normal tissue. Tumor:normal tissue ratios of 0.9-10.0 and tumor:blood ratios of 0.3-4.0 were seen up to 168 h after injection. Localization of the HMFG2 conjugate was consistently greater than that of the irrelevant antibody. For solid tumor, the i.v. route of administration resulted in consistently higher absolute levels of HMFG2 conjugate uptake but tumor:blood and tumor:normal tissue ratios were similar. On the other hand the i.p. route of administration offered consistent advantages of 4- to 71-fold over the i.v. route when HMFG2 conjugate localization on ascites cells was examined. Ascites:normal tissue and ascites:blood ratios of up to 512 and 448, respectively, were achieved. After i.p. injection, radioiodine was cleared from the body exponentially with a half-life of 50 h. Maximum circulating blood levels of 8.6 +/- 2.0% injected activity were seen at 48 h and these then decreased with a t 1/2 value of 38 h. Over 80% of injected activity was cleared in the urine as nonprotein bound iodine by 168 h.
Sixty-five patients with advanced colorectal cancer were randomised to one of two schedules of recombinant alpha-2 interferon (IFN). In the first study, 36 patients received single-agent IFN, either 50 X 10(6) U/m2 intravenously on 5 consecutive days every 4 weeks, or 20 X 10(6) U/m2 subcutaneously three times per week. No tumour responses were seen and toxicity was unacceptable. In the second study, 29 patients received IFN in two similar schedules, but the dose of IFN was reduced to 20 X 10(6) U/m2 per day in the intravenous arm and to 5 X 10(6) U/m2 per day in the subcutaneous arm. In addition these patients were administered intravenous 5-Fluorouracil (5-FU), 250-500 mg/m2 per day on the first 5 days of each 4-weekly cycle. Although the toxicity of this second study was tolerable, only one short-lived partial remission was observed. Alpha-2 interferon, alone or in combination with 5-FU, is ineffective in advanced colorectal cancer.
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Combination chemotherapy using vindesine and cisplatinum has been reported to be active in non-small cell lung carcinoma (NSCLC). In an attempt to reduce the potential neurotoxicity of this combination, and to assess the role of cisplatinum, a randomized trial has compared vindesine and cisplatinum to vindesine and methotrexate in 48 patients with advanced symptomatic NSCLC. Patient characteristics were similar in the two treatment arms. Objective tumour response and survival were similar for both treatments. No complete response occurred. Four patients receiving vindesine/cisplatinum (16%) and three patients receiving vindesine/methotrexate (13%) had a partial response. All responses occurred in patients with a performance status of 70% or more and no response was seen in patients with squamous cell carcinoma. Median survival for both regimens was 16 weeks. Toxicity was considerable and only six patients (12.5%) felt better on treatment. Nausea and vomiting were more frequent in the vindesine/cisplatinum arm, but mild neurotoxicity was more common in the vindesine/methotrexate arm. The low response rates, short survival and significant toxicity suggest that the role of combination chemotherapy in NSCLC remains to be established.
High dose melphalan (HDM, 140 mg/m2 i.v.) has been evaluated in 58 patients under 63 years with multiple myeloma. Among previously untreated patients 11/41 (27%) entered a complete remission (CR: no measurable myeloma protein and a normal bone marrow) and 21 (51%) entered a partial remission (more than 50% reduction in myeloma protein and improvement in all other features). Median duration of remission is 19 months. Two patients who had responded to previous conventional treatment entered CR after HDM. Among 15 patients who had failed on previous chemotherapy the response rate was 66% including two CRs. However, in this group all patients have relapsed within 1 year. Profound myelosuppression, moderate nausea, vomiting, mucositis and diarrhoea with reversible alopecia occurred in all patients. There were 10 deaths within 2 months of treatment mainly due to sepsis and haemorrhage. In a subsequent study, high dose methyl prednisolone (1 g/m2 daily for 5 d) has been added to HDM. Response rates are similar with 6/22 (27%) CR, 13/22 (59%) PR and 2/22 NR but there was only one early death, reflecting improvements in medical management. The high CR rate is an encouraging feature of this approach which is now to be the basis of a prospective trial sponsored by the Medical Research Council in which HDM, with and without steroids, is compared to the best available conventional therapy (the MRC VI Myelomatosis trial).
The phase specificity and short half-life of bleomycin make it likely that it would be more effective when administered by continuous infusion. This is supported by studies using cell lines, as well as by animal studies and clinical experience in humans. This study was conducted to compare the pharmacokinetics of intravenous (IV) and subcutaneous infusions of bleomycin. The serum concentrations of bleomycin were measured using a sensitive and specific radioimmunoassay. The results demonstrate similar plasma concentrations and area under the curve for both routes. The subcutaneous infusions were well tolerated, without local discomfort or excoriation. Subcutaneous infusion of bleomycin may thus offer a practical alternative to IV infusions and can be administered to patients who are ambulatory and out of hospital.
Etoposide and teniposide are semisynthetic derivatives of podophyllotoxin and are increasingly used in cancer medicine. Teniposide is more highly protein-bound than etoposide, and its uptake and binding to cells is also greater. Etoposide and teniposide are phase-specific cytotoxic drugs acting in the late S and early G2 phases of the cell cycle. They appear to act by causing breaks in DNA via an interaction with DNA topoisomerase II or by the formation of free radicals. Teniposide is more potent as regards the production of DNA damage and cytotoxicity. Most studies show a biexponential decay following intravenous administration of etoposide and teniposide. The terminal elimination half-life of etoposide is less than that of teniposide, and the plasma and renal clearances of etoposide are greater. The peak plasma concentrations of drug and the area under the concentration versus time curve are linearly related to the intravenous dose of both drugs. Considerable interpatient variability of pharmacokinetic parameters exists following intravenous etoposide and teniposide. Various metabolites of etoposide and teniposide have been identified but their detection and quantitation are disputed. Approximately 30 to 70% of a dose of etoposide is accounted for by excretion, whereas the figure appears to be only 5 to 20% for teniposide. The bioavailability of oral etoposide is about 50% but its absorption is not linear with increasing dose within the range in clinical use. There is considerable inter- and intrapatient variability in the pharmacokinetics of oral etoposide. There is no evidence of accumulation of etoposide and teniposide after multiple consecutive doses by the intravenous or oral routes. The exact roles of the liver and kidney in metabolism and excretion of etoposide and teniposide are uncertain. Etoposide has been shown to be a highly schedule-dependent drug in clinical studies. This together with the phase-specific action of etoposide and teniposide and their increasingly widespread use in cancer medicine make the clinical pharmacology of these drugs of great clinical importance.
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Explore the source record for details and available documents.
Doctors who have not come to terms with their own feelings about serious illness and dying may experience considerable embarrassment and feel ill at ease when discussing these subjects with patients. The problems of communicating with patients and ways in which they can be resolved are reflected upon.
Reduced food intake is a common problem in patients with malignant disease. Oral supplementation is the simplest and least invasive method of increasing the nutrient intake, and a number of neutral protein and energy supplements are available. This study was carried out to assess the value of these supplements when incorporated into the everyday diet of cancer patients. The first stage of the study evaluated the palatability of the energy and protein supplements available. Polycal was found to be the most acceptable energy supplement and Protifar the most acceptable protein supplement. These two products were then used to assess their contribution to the protein and energy intake of cancer patients when incorporated into everyday food. The rise in protein and energy intake was statistically significant but the increase in energy was not thought to be clinically important.
Patients with impaired renal function may experience severe and prolonged respiratory depression when treated with morphine. This has been attributed to accumulation of the drug during renal failure. Three patients are described who had classical signs of intoxication with morphine in the absence of measurable quantities of morphine in the plasma. The observed clinical effect is attributed to accumulation of the pharmacologically active metabolite morphine-6-glucuronide, which is usually renally excreted. It is concluded that morphine does not accumulate in patients with renal failure but that accumulation of metabolites does occur. The previously reported observations of morphine accumulation during renal failure probably result from the use of radioimmunoassays that cannot distinguish between morphine and morphine-6-glucuronide. Thus the apparent morphine concentration measured with these assays in fact reflects the total quantity of morphine and morphine-6-glucuronide present.
The bioavailability of orally administered etoposide varies considerably. The effect of dose on bioavailability has not previously been investigated. In this study six patients were each treated with oral etoposide at doses of 200, 400, and 600 mg, and the pharmacokinetics determined. Each patient acted as his own control. The area under the plasma concentration-time curve (AUC) was proportionately greatest at the lowest dose. Doubling the dose from 200 mg to 400 mg increased AUC by only 50%, and a further increase of only 2.2% occurred at a dose of 600 mg. These data show nonlinear bioavailability of etoposide within the range in clinical use and may explain the variable results of reported studies. The data may have important implications for chemotherapy regimens with oral etoposide.
Forty-one patients with advanced progressing carcinoma of the cervix were treated with ifosfamide 1.5 g/m2 daily in a 30-min infusion for 5 days every 3 weeks. The overall response rate (complete + partial) was 12/39 (31%), or 12/30 (40%) in those who had not received previous chemotherapy. Six patients achieved a complete remission of disease and four of these remain disease-free 24-39 months later. Durable response were seen in patients with disease progressing after radical radiotherapy. Bone marrow suppression was the dose-limiting toxicity and led to dosage modification in 24 patients. Nausea and vomiting was experienced by all patients at some time during therapy and all patients developed alopecia. Mild neurological toxicity occurred in seven patients but severe life-threatening neurotoxicity was not seen with this schedule of administration. Further studies are needed to identify the optimum dose and schedule of ifosfamide and to ascertain its place in combination therapy.