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M L Slevin

Publications and source records attributed to M L Slevin.

At least 55 records · Page 3Linked to original sources
PubMed1992

Measuring cytokine levels in blood. Importance of anticoagulants, processing, and storage conditions.

The stability and recovery of six human recombinant cytokines (tumour necrosis factor (TNF), interferon-alpha (IFN-alpha), IFN-gamma, interleukin-1 alpha (IL-1 alpha), IL-1 beta, and IL-6) from whole blood was investigated with a view to optimizing blood collection and storage procedures prior to performing immunoassays. Blood from healthy volunteers was subjected to various processing and storage procedures. Blood samples were treated with either: ethylenediamine tetraacetic acid (EDTA) (1.5 mg/ml blood) (E); EDTA/Trasylol (1.5 mg and 1000 KIU/ml blood) (ET); heparin (30 IU/ml) (H) or allowed to clot (serum). The bloods were spiked with individual cytokines, split into aliquots and kept at 4 degrees C or RT. In the first instance spiked bloods from healthy volunteers (n = 5 per cytokine) were processed using sterile and non-pyrogenic materials and procedures. At regular time intervals, samples were cold spun, separated, flash frozen and assayed for the appropriate cytokine using RIA/IRMA methods. In a further study, timed separation was repeated with spiked blood from healthy volunteers (n = 5 per cytokine) using normal commercially available blood collection materials and procedures. In a third study, spiked blood from healthy volunteers (n = 3 per cytokine) was processed under sterile and non-pyrogenic conditions, and the blood samples separated, aliquoted and flash frozen within half hour of collection. These were then subjected to repeated cycles of freeze thawing at 4 degrees C or RT before assaying. In general, the stability of cytokines in whole blood was improved by storage at 4 degrees C and/or rapid separation. There was no significant difference between samples handled under sterile, non-pyrogenic conditions and those collected using normal blood collection procedures. The blood collection procedures described in this paper did not induce any of the six cytokines in the unspiked blood. Overall, EDTA-treated samples performed most consistently. The addition of trasylol did not significantly affect the results. Most of the cytokines appeared unaffected by up to three freeze thaw cycles. The stability and recovery of the spiked cytokines varied from least stable to most stable spiked cytokine as follows; TNF-alpha less than IL-6 less than IFN-gamma less than IL-1 alpha less than IFN-alpha less than IL-1 beta. The recovery of spiked IFN-gamma from heparinized plasma samples was considerably higher than any other plasma or serum samples. The recovery of spiked TNF-alpha and IL-6 from serum samples was consistently lower than amounts recovered from plasma samples (anticoagulant treated).(ABSTRACT TRUNCATED AT 400 WORDS)

Anticoagulants↗
PubMed1992

Explanation at the opioid receptor level for differing toxicity of morphine and morphine 6-glucuronide.

The radiolabelled opioid receptor binding affinities of morphine and its active metabolite morphine 6-glucuronide at the total mu, mu 1, mu 2 and delta receptors were determined. Morphine 6-glucuronide was found to have a 4-fold lower affinity for the mu 2 receptor (IC50 17 nM and 82 nM for morphine and morphine 6-glucuronide respectively, P = 0.01), the receptor postulated to be responsible for mediating the respiratory depression and gastrointestinal effects after morphine. This provides a possible explanation for the reduced respiratory depression and vomiting seen following morphine 6-glucuronide in man. A similar reduction in affinity of morphine 6-glucuronide was seen at the total mu receptor whilst there was no significant difference seen at the mu 1 or delta receptor. Hence the increased analgesic potency of morphine 6-glucuronide over morphine remains unexplained.

Animals↗
PubMed1992

Morphine 6-glucuronide: a metabolite of morphine with greater emetic potency than morphine in the ferret.

1. The emetic potencies of morphine and its metabolite morphine 6-glucuronide have been determined in the ferret by constructing dose-response curves for mean total retches and vomits for subcutaneous doses of 0.05 mg kg-1 to 5 mg kg-1. Morphine 6-glucuronide induced retching and vomiting at lower doses than morphine and at a maximal dose induced more retching and vomiting than morphine. 2. The emesis induced by both morphine and morphine 6-glucuronide was abolished by the preadministration of naloxone (0.5 mg kg-1 s.c.). 3. The 5-HT3 receptor antagonists granisetron and ondansetron (1 mg kg-1, s.c.) failed to abolish or reduce emesis induced by either compound. 4. At a high-dose (5 mg kg-1), morphine but not morphine 6-glucuronide failed to induce emesis and abolished the emesis induced by the cytotoxic drug, cyclophosphamide (200 mg kg-1, i.p.). 5. Preliminary pharmacokinetic studies of intravenous and subcutaneous morphine and morphine 6-glucuronide revealed that morphine 6-glucuronide accounts for less than 1% of the metabolic product of morphine in the ferret. Peak plasma levels of the two compounds after their subcutaneous administration were obtained within 10 min. The metabolic profile of morphine was not dose-dependent. There was no relationship between plasma level and emetic response for either compound.

Animals↗
PubMed1991

A mathematical model relating response durations to amount of subclinical resistant disease.

A mathematical model is presented which seeks to determine, from examination of the response durations of a group of patients with malignant disease, the mean and distribution of the resistant tumor volume. The mean tumor-doubling time and distribution of doubling times are also estimated. The model assumes that in a group of patients there is a log-normal distribution both of resistant disease and of tumor-doubling times and implies that the shapes of certain parts of an actuarial response-duration curve are related to these two factors. The model has been applied to data from two reported acute leukemia trials: (a) a recent acute myelogenous leukemia trial was examined. Close fits were obtained for both the first and second remission-duration curves. The model results suggested that patients with long first remissions had less resistant disease and had tumors with slower growth rates following second line treatment; (b) an historical study of maintenance therapy for acute lymphoblastic leukemia was used to estimate the mean cell-kill (approximately 10(4) cells) achieved with single agent, 6-mercaptopurine. Application of the model may have clinical relevance, for example, in identifying groups of patients likely to benefit from further intensification of treatment.

Humans↗
PubMed1991

The clinical pharmacology of etoposide.

Etoposide, a semisynthetic derivative of podophyllotoxin, is increasingly used to treat cancer. Etoposide is a phase-specific, cytotoxic drug acting in the late S and early G2 phases of the cell cycle. It appears to cause breaks in DNA by either an interaction with DNA-topoisomerase II or the formation of free radicals. Most studies show a biexponential decay after the intravenous (IV) administration of etoposide. The peak plasma concentrations of drug and the area under the concentration versus time curve (AUC) are linearly related to the IV dose. Considerable interpatient variability of pharmacokinetic variables exists after IV etoposide. Various metabolites of etoposide have been identified, but their detection and quantitation are disputed. Approximately 30% to 70% of an etoposide dose is excreted. The bioavailability of oral etoposide is approximately 50%, but its absorption is not linear with increasing doses within the range in clinical use. Considerable interpatient and intrapatient variability exists in the pharmacokinetics of oral etoposide. There is no evidence of etoposide accumulation after multiple consecutive doses by either the IV or oral route. The exact roles of the liver and kidney in metabolism and excretion of etoposide 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 its increasingly widespread use in treating cancer, makes the clinical pharmacology of this drug of great clinical importance.

Etoposide↗
PubMed1991

A less toxic regimen of 5-fluorouracil and high-dose folinic acid for advanced gastrointestinal adenocarcinomas.

The combination of high-dose folinic acid with 5-fluorouracil has shown improved response rates in several trials in advanced colorectal carcinoma. This however is at the expense of increased toxicity: regimens using weekly bolus injections produce diarrhoea in most patients and occasional toxic deaths from this, whilst those using daily injections for one week in four report both diarrhoea and severe oral mucositis. Both types of regimen have significant rates of myelosuppression. A recent report described a different schedule of 5-fluorouracil and folinic acid, which appeared better tolerated but equally active (De Gramont et al., 1988). Here we report results using the same programme, in 64 patients with advanced adenocarcinomas. (Forty three colorectal, ten gastric, six pancreatic and five of unknown primary.) Patients received 200 mg m-2 folinic acid by infusion over 2 h followed by an IV bolus of 5-fluorouracil 400 mg m-2 then an infusion of 5-fluorouracil 400 mg m-2 over 22 h. This was repeated over the next 24 h. The schedule was given every 2 weeks for a total of six to 12 courses depending upon the response. The overall response rate was 26% in 62 evaluable patients. No toxicity greater than WHO Grade II occurred. Diarrhoea and mucositis did occur in around 10% of treatments but were not troublesome. No febrile neutropenic episodes were seen. Despite previous reports which described only modest activity for this combination against stomach cancers, this regimen demonstrates low toxicity but retains good activity in the palliative treatment of both gastric and colonic adenocarcinomas.

Adenocarcinoma↗
PubMed1991

A new treatment for endometrial cancer with gonadotrophin releasing-hormone analogue.

OBJECTIVE: To test the antitumour effect of gonadotrophin releasing-hormone (GnRH) analogues in women with recurrent endometrial cancer. DESIGN: An open phase II observational trial of GnRH analogues. Serial measurements of gonadotrophins, sex hormones and tumour dimensions were made together with repeat biopsy when possible to assess the response to treatment. SETTING: The outpatient clinics of the Department of Medical Oncology at The Royal London, Royal Marsden and St Bartholomew's hospitals. SUBJECTS: 17 patients with endometrial cancer which had recurred after surgery, radiotherapy and progesterone treatment and was symptomatic, progressive and assessable for response. INTERVENTION: Monthly subcutaneous injection of GnRH analogue. MAIN OUTCOME MEASURES: Reduction in serum gonadotrophins and reduction in tumour dimensions. RESULTS: Six out of 17 patients (35%, 95% CI 12.6-58%) achieved a complete or partial remission which continues for a median of 20 months with no adverse effects. CONCLUSION: GnRH analogues have a significant antitumour effect in recurrent endometrial cancer which warrants further examination in comparison with progestogens.

Adenocarcinoma↗
PubMed1990

Attitudes to chemotherapy: comparing views of patients with cancer with those of doctors, nurses, and general public.

OBJECTIVE: To compare responses of patients with cancer with those of a matched control group, cancer specialists, general practitioners, and cancer nurses in assessing personal cost-benefit of chemotherapy. DESIGN: Prospective study of consecutively recruited patients with cancer and other groups by questionnaire; half of the patients received the questionnaire again three months after starting treatment. SETTING: A medical oncology ward of a London teaching hospital. SUBJECTS: 106 Patients with newly diagnosed solid tumours referred to the unit for consideration of treatment with cytotoxic chemotherapy, 100 of whom were able to complete the questionnaire. 100 Matched controls, 315 cancer doctors (238 radiotherapists and 77 medical oncologists), 1500 randomly chosen general practitioners, and 1000 randomly chosen cancer nurses. MAIN OUTCOME MEASURES: Percentage chance of cure, prolonging life, or palliation of symptoms required to make treatment worth while with two hypothetical chemotherapy treatments, with severe and mild side effects respectively. RESULTS: Respondents to the questionnaire comprised 100 patients, 100 controls, 60 (78%) medical oncologists, 88 (37%) radiotherapists, 790 (53%) general practitioners, and 303 (30%) cancer nurses. Most patients were willing to accept intensive chemotherapy for a very small chance of benefit. The median benefit required to make the hypothetical intensive treatments worth while for patients compared with controls were: for chance of a cure (range 1 to 100%) 1% v 50%, for prolonging life (range three months to five years) 12 months v 24-60 months, and for relief of symptoms (range 1 to 100%) 10% v 75% respectively. There were no significant differences in the responses of the 50 patients completing the questionnaire on a second occasion. Doctors and nurses were less likely to accept radical treatment for minimal benefit compared with the patients (median scores 10-50%, 12-24 months, and 50-75%, for chance of cure, prolonging life, and relief of symptoms respectively). Significantly more patients than controls accepted treatments giving the minimal benefit for each category (cure 53.1 v 19.0%, 67.0 v 35.0%; prolonging life 42.1 v 10.0%, 53.0 v 25.0%; relief of symptoms 42.6 v 10.0%, 58.7 v 19.0% for intensive and mild treatments respectively, p less than 0.001) as was the case for comparison of patients with other groups. CONCLUSION: Patients with cancer are much more likely to opt for radical treatment with minimal chance of benefit than people who do not have cancer, including medical and nursing professionals. This could be taken into account when discussing treatment options with patients and their relatives.

Antineoplastic Agents↗
PubMed1990

A phase II study of ifosfamide and cisplatin chemotherapy for metastatic or relapsed carcinoma of the cervix.

A total of 44 women received a combination of ifosfamide (1.5 g/m2 daily x5) and cisplatin (50 mg/m2 on day 1 only) as first-line chemotherapy for recurrent or metastatic carcinoma of the cervix. In all, 12/42 (38%) evaluable patients responded, with the median duration of response being 7 months. Bone marrow and gastrointestinal toxicity were frequently severe. There were 3 septic deaths. Although cisplatin plus ifosfamide is an active combination against this disease, these results suggest that it is no more so than either drug used alone.

Adult↗