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Biomedical subjects

J Smyth

Publications and source records attributed to J Smyth.

69 records · Page 4Linked to original sources
PubMed1987

Experimental cerebral and plasma pharmacokinetic studies of TCNU: implications for brain tumour chemotherapy.

This study of the pharmacokinetics of TCNU, a new nitrosourea, in the rodent has shown that TCNU concentrations in the plasma (ng/ml) and brain (ng/g) are equivalent from 15 min to 4 hours after drug administration. The absolute levels of TCNU obtained with a dose of 100 mg TCNU/kg bodyweight were at most time points, three to four times those obtained with dosage of 25 mg TCNU/kg. The profile of rodent plasma TCNU levels following drug administration is similar to that recorded in humans, with peak TCNU concentrations occurring around 45 min. Since TCNU crosses an intact blood brain barrier (BBB), and clinical Phase I trials have shown it to possess potent antitumour properties. It may be a useful agent in the management of primary and secondary cerebral neoplasia.

Animals↗
PubMed1987

Providing census data for general practice. 1. Feasibility.

The availability of census data to general practice is limited by the form of publication, restricted access to computerized data and the technical difficulties of linking computerized information to a practice population. In a feasibility study it is shown how a population registered with a general practice may be linked through postcodes to computerized enumeration district data. Examples of the data available are discussed together with current problems of postcode/enumeration district mismatch. Suggestions are made for ensuring that general practitioners have access to the 1991 census data.

Catchment Area, Health↗
PubMed1987

Providing census data for general practice. 2. Usefulness.

Computerized census data are described in relation to a general practice population. The previously published methods for scoring deprivation - underprivileged areas score and material deprivation score - are applied to the data. Wards and enumeration districts within a single practice area are ranked by both methods and examples show the wide variation in deprivation scores for enumeration districts within single wards. The value of these data to a general practice is discussed with particular reference to developing a profile of the practice and to planning prevention and anticipatory care.

Catchment Area, Health↗
PubMed1985

Payment by results.

Explore the source record for details and available documents.

Employee Incentive Plans↗
PubMed1985

Mitoxantrone as first-line chemotherapy in advanced breast cancer: results of a collaborative European study.

Mitoxantrone (Novantrone; dihydroxyanthracenedione) is a substituted anthraquinone with a spectrum of activity similar to doxorubicin in experimental tumors. One hundred and seventy three patients with advanced breast cancer and no prior cytotoxic therapy for advanced disease entered a phase II study of mitoxantrone, 14 mg/m2 i.v. repeated every 3 weeks. At the time of this analysis 116 patients were evaluable. Eight patients achieved a complete response and 27 a partial response, the overall response rate being 30% (95% confidence limits: 22-39%). The median time until response was recorded was 15 weeks. The median duration of response was 74+ weeks and the median time to progression or death for all 116 patients was 22+ weeks. Mitoxantrone was well tolerated with myelosuppression as the dose-limiting toxicity. The most frequent non-haematological toxicities were nausea and vomiting (65%) but they were rarely severe. Total alopecia occurred in only 6% of the patients. Four patients developed clinically significant evidence of cardiotoxicity after cumulative mitoxantrone doses of 174-256 mg/m2. Thus, mitoxantrone offers comparable efficacy and less acute toxicity than the most active single agents currently available in the treatment of advanced breast cancer.

Adult↗
PubMed1983

Role of chemotherapy in small cell lung cancer: a consensus report of the International Association for the Study of Lung Cancer workshop.

Many studies in small cell carcinoma of the lung (SCCL) have demonstrated a high response rate and a potential for cure in a subset of patients. Combination chemotherapy, the cornerstone of all treatment for SCCL, can produce up to 10% long-term, disease-free survival among all patients with SCCL and greater than or equal to 20% survival among patients who present with limited disease. Significant improvements in survival have occurred in all stages of disease, and further investigative efforts are necessary to improve the complete remission rate, the duration of response, and the percentage of long-term, disease-free survivors. The current report, based on the workshop on SCCL held in Ireland under the auspices of the International Association for the Study of Lung Cancer, reviews the current state of the art for chemotherapy and presents potential future directions.

Antineoplastic Agents↗
PubMed1979

Nature of 6-methylpurine inhibition and characterization of two 6-methylpurine-resistant mutants of Neurospora crassa.

6-Methylpurine, an analog of adenine, inhibits the growth of Neurospora crassa. From kinetic studies it was found that 6-methylpurine is converted to its nucleotide form by adenine phosphoribosyltransferase (EC 2.4.2.7), and inhibits the de novo purine biosynthesis. Adenine relieves the growth inhibition caused by 6-methylpurine, whereas hypoxanthine is not very effective. Studies dealing with hypoxanthine utilization in the presence of 6-methylpurine indicated a severely reduced uptake of hypoxanthine and a general slowdown in its further metabolism. Two mutants (Mepr-3 and Mepr-10) which are resistant to 6-methylpurine were characterized. Studies of purine base uptake and the in vivo and in vitro conversion to nucleotides indicated that Mepr-10 may be an adenine phosphoribosyltransferase-defective mutant, whereas Mepr-3 may be a mutant with altered feedback response to 6-methylpurine. Both mutants showed a severely lowered hypoxanthine phosphoribosyltransferase activity, but because 6-methylpurine did not have any effect on the conversion of hypoxanthine to IMP in the wild type, it was concluded that 6-methylpurine resistance in these mutants cannot be due to lowered hypoxanthine phosphoribosyltransferase activity, but rather that the lowering of enzyme activity may be a secondary effect.

Adenine Nucleotides↗
PubMedDate not supplied

Effect of chronic stress associated with unemployment on salivary cortisol: overall cortisol levels, diurnal rhythm, and acute stress reactivity.

This study examined the effect of chronic stress associated with unemployment on the magnitude of salivary cortisol excretion, on the diurnal rhythm of cortisol, and on cortisol reactivity to acute naturalistic stressors using Experience Sampling Methodology (ESM). Employed (N = 60) and unemployed (N = 60) subjects were studied for 2 days. Subjects were beeped 6 times per day by a preprogrammed wristwatch to assess acute stressors; 25 minutes after each ESM-beep, subjects were beeped a second time for saliva samples. The groups did not differ in their overall cortisol excretion or in cortisol reactivity to acute daily stressors. Compared to employed subjects, unemployed subjects had a diurnal pattern of cortisol excretion with relatively higher morning and lower evening levels. Subjects' daily activities and their locations were associated with diurnal rhythm differences.

Adult↗