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Biomedical subjects

D J Kerr

Publications and source records attributed to D J Kerr.

At least 199 records · Page 11Linked to original sources
PubMed1986

Comparative intracellular uptake of adriamycin and 4'-deoxydoxorubicin by non-small cell lung tumor cells in culture and its relationship to cell survival.

4'-Deoxydoxorubicin (4'-deoxy) is a new adriamycin analogue with a similar spectrum of antitumour activity but is significantly more lipophilic than the parent compound. We report the kinetics and uptake of the two drugs by human non-small cell lung tumour cells in monolayer culture and the relationship between intracellular drug levels and cytotoxicity. The rate and degree of cell uptake of 4'-deoxy (Vmax = 30 ng/10(5) cells/min) was greater than that of adriamycin (Vmax = 0.15 ng/10(5) cells/min). Although for a given intracellular drug concentration adriamycin was more lethal, on the basis of extracellular drug concentration, cell kill was virtually identical. The log cell survival vs intracellular drug concentration plot was linear for adriamycin but biphasic for 4'-deoxy. Intracellular distribution of the two drugs was followed by fluorescent microscopy and it was apparent that adriamycin was localized mainly within the nucleus whereas 4'-deoxy accumulated within the cytoplasm. Our results suggest that the relationship between intracellular distribution of the two drugs could reflect different modes of action for the drugs with respect to binding sites or could be a non-specific phenomenon, unrelated to lethal effects.

Carcinoma, Squamous Cell↗
PubMed1986

The effect of verapamil on the pharmacokinetics of adriamycin.

The concurrent administration of adriamycin (intravenous) and verapamil (oral) is of considerable interest because of experimental data suggesting that resistance to adriamycin may be overcome by this means. The potential for a pharmacokinetic interaction between the two drugs has therefore been investigated in five patients with small cell lung cancer treated with combination chemotherapy comprising adriamycin, VP16, vincristine and cyclophosphamide. The data indicate that a significant interaction takes place. Adriamycin peak levels, terminal half-life and the volume of distribution at steady state are higher, whereas plasma drug clearance and the volume of the central compartment are lower with co-administration of verapamil. There was no evidence of enhanced drug toxicity in this study; however, the data should be considered in the interpretation of clinical trials in which adriamycin and verapamil are used together, both in terms of toxicity and tumour response.

Administration, Oral↗
PubMed1986

The effect of 5-fluorouracil on rat adrenal function.

This study was undertaken to determine the effects of 5-fluorouracil on corticosteroidogenesis and adrenal size in the rat. The rats were injected intraperitoneally with 5-FU (12.5 mg kg-1 or 25 mg kg-1), normal saline or actinomycin D (0.02 mg kg-1), daily for 10 days. High-dose 5-FU induces adrenal hyperplasia, in association with mild impairment of corticosteroidogenesis (manifest by lower corticosterone and higher ACTH levels). The response to low-dose 5-FU and actinomycin D is of lesser adrenal hyperplasia, relative to high-dose 5-FU (P less than 0.05) and elevated corticosterone levels. There may be a dose-related effect on the suppression of corticosteroidogenesis in the rat by 5-FU.

Adrenal Cortex↗
PubMed1986

The effect of adriamycin and 4'-deoxydoxorubicin on cell survival of human lung tumour cells grown in monolayer and as spheroids.

Using growth delay and clonogenic cell survival as end points, we have shown that the 3-dimensional structure of human lung tumour spheroids confers a degree of resistance to the anthracyclines adriamycin and 4'-deoxydoxorubicin, relative to cells grown as monolayer. 4'-deoxydoxorubicin induces a longer growth delay and greater clonogenic cell kill than adriamycin in spheroids, although it is no more cytotoxic in monolayer (exponential and plateau phase). There is a log linear relationship between clonogenic cell survival and duration of adriamycin exposure in monolayers, and biphasic curve with a lesser degree of cell kill for disaggregated spheroid cells. Using fluorescent microscopy we have demonstrated, qualitatively, that the more lipophilic analogue partitions into the spheroid more rapidly and to a greater degree than adriamycin. It is possible that adriamycin penetration is a relatively important aspect of spheroid drug resistance, which may be related to intraspheroidal pH gradients, and that we have partially overcome this by using a lipophilic analogue.

Cell Survival↗
PubMed1986

Prognostic factors in thyroid tumours.

Using Cox's Proportional Hazard Model, we have demonstrated the influence of age, sex, microscopic tumour type, extent of primary tumour, nodal status and the presence of metastases on prognosis, in our population of 441 patients with thyroid carcinoma. The TNM classification contributes significantly to survival, but does not include other contributory prognostic variables, whereas the prognostic index developed by the EORTC thyroid study group, which takes account of age and histology, proved a reliable predictor of survival for our patient group.

Age Factors↗
PubMed1986

Serum and peritoneal dialysate thyroid hormone levels in patients on continuous ambulatory peritoneal dialysis.

Thyroid function tests were performed on 16 clinically euthyroid patients with end-stage renal failure undergoing regular haemodialysis or continuous ambulatory peritoneal dialysis and compared with 8 healthy subjects. The patient groups were carefully matched, especially regarding relative duration of dialysis (mean of 24 months). Total serum thyroxine, total triiodothyronine, free thyroxine, free triiodothyronine and reverse triiodothyronine were significantly lower in both patient groups than control. The thyrothrophin response to the standard thyrotrophin-releasing hormone test was delayed and blunted. Using a novel concentration technique we measured loss of T4 in peritoneal dialysate effluent and found it to be approximately 10% of daily thyroidal T4 release.

Adult↗
PubMed1986

Phase I and pharmacokinetic study of LM985 (flavone acetic acid ester).

We have conducted a Phase I and initial clinical pharmacological evaluation of LM985, the first of a series of compounds based on the flavone ring structure to be considered for clinical trial in malignant disease. The drug was administered i.v. to 26 patients with advanced cancer on an every-21-day schedule. Patients were treated at 14 dosage levels ranging from 10 to 1500 mg/m2. Dose limiting toxicity was identified as acute reversible hypotension occurring during drug infusion; no leukopenia, alopecia, hepatic toxicity, or renal toxicity was observed, but at the higher dose range, mild sedation was apparent. Twenty patients had measurable disease and were evaluable for response. One patient with colorectal carcinoma had stable disease after three courses of LM985; however, no other responses were seen. Pharmacokinetic and in vitro drug degradation studies imply that the ester LM985 is hydrolyzed to LM975 (flavone acetic acid) rapidly in vivo. LM975 is active in a variety of animal tumor models, but it does not have the cardiovascular side effects seen with LM985 (hypotension and bradycardia) in pithed or anesthetized rats. We would recommend that LM975 be considered for clinical trial, because it seems likely that substantially higher doses of LM975 than of LM985 can be given without dose limiting cardiovascular toxicity.

Adult↗
PubMed1985

Pseudohyperkalaemia.

When the serum potassium concentration is raised and there is no clinical or electrocardiographic evidence of hyperkalaemia pseudohyperkalaemia must be considered.

Aged↗
PubMed1985

Lymphoid and epithelial markers in small cell anaplastic thyroid tumours.

The expression of the lymphoid marker, common leucocyte antigen and of the epithelial marker, epithelial membrane antigen by small cell anaplastic thyroid tumours was studied in 53 tumours, using the peroxidase--antiperoxidase and avidin--biotin techniques. Common leucocyte antigen was found in 33 of the 53 tumours; six tumours were positive for epithelial membrane antigen; and the remaining 14 tumours were negative for both markers. These results support the suggestion that most small cell anaplastic thyroid tumours are of lymphoid origin. Survival data for patients with tumours positive for common leucocyte antigen showed a significantly better prognosis than did the data for patients with small cell tumours that did not express this marker (p less than 0.02).

Antigens, Neoplasm↗
PubMed1966

Half-leg air band.

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Fracture Fixation↗