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Biomedical subjects

D R Taylor

Publications and source records attributed to D R Taylor.

At least 127 records · Page 7Linked to original sources
PubMed1984

Patient compliance with oral theophylline therapy.

Day-to-day variations in plasma theophylline concentrations at steady-state have been assessed in 29 hospital inpatients who required theophylline for obstructive airways disease. Plasma concentrations were measured at 09.00h and 14.00h for four consecutive days in the equilibrium state in 13 patients taking 350 mg/day and 16 patients taking 700 mg/day. Analysis of variance gave 95% confidence limits for day-to-day variation of +/- 2.9 micrograms/ml at 350 mg/day and +/- 4.8 micrograms/ml at 700 mg/day. In a separate study, compliance with sustained-release theophylline therapy has been assessed in a group of 63 patients receiving the drug in general practice but not attending hospital. Compliance was estimated by comparing plasma theophylline concentrations before and after a 7-day period of measured theophylline consumption and by tablet counting. Of the 63 patients, 16 had discontinued their theophylline prior to being contacted and two did so during the first week: these were considered non-compliant. Three patients had plasma concentrations which increased by more than the day-to-day variation for their dose level during monitored intake and one other took less than 80% of his tablets. These patients were also considered non-compliant. A further four patients in whom plasma theophylline levels were zero on at least one occasion during the study were also adjudged non-compliant. Thus non-compliance with prescribed theophylline dosage occurred in 26 (41.3%) of the patients studied. In the majority of these, treatment had been discontinued and the non-compliance was gross.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Circadian variation in plasma theophylline concentrations during maintenance therapy with a sustained-release preparation in patients with obstructive airways disease.

Circadian variation in plasma theophylline concentrations was studied in eight patients with obstructive airways disease during regular 12-hourly dosing at 09.00 and 21.00 h with a sustained-release theophylline formulation. After regular dosing for a minimum period of 3 days, plasma concentration measurements were made at 09.00, 13.00, 21.00 and 01.00 h on 3 consecutive days and at more regular intervals during a complete 24 h period on day 4. On each day, theophylline concentrations for the first 4 h of the dosing interval were consistently higher during the day than at night. However, the differences were significant only at 13.00/01.00 h on day 2, and for each of the first 4 h on day 4. On day 4, following the dose at 21.00 h the mean peak plasma theophylline concentration occurred 6.9 +/- 0.8 h after dosing; in contrast, after the morning dose the mean peak concentration occurred at 4.5 +/- 0.8 h. However, the mean 'steady-state' concentrations during the two dose intervals were not significantly different. Thus circadian variations in plasma drug concentrations do occur in patients taking maintenance theophylline therapy: differing rates of absorption may account for the observed pattern.

Aged↗
PubMed1984

Increased ratio of helper to suppressor T cells in alopecia areata.

We studied lymphocyte subsets in the blood of twenty-four patients with alopecia areata of various degrees of severity. There was an increase in the ratio of helper to suppressor cells that correlated with the extent of the disease, providing further evidence that the immune system may be involved in its pathogenesis.

Adolescent↗
PubMed1983

Prediction of optimum oral theophylline dose in patients with obstructive airways disease.

The hypothesis that a logarithmic correlation exists between the plasma theophylline concentrations 6 h after a test dose C(6) and the maintenance dose calculated to achieve a desired drug concentration during chronic oral administration (DM,CALC) was tested. A nomogram based on this relationship was evaluated as a means of predicting the optimum dose of theophylline in 14 patients with obstructive airways disease (DM,PRED). Each patient was given 5 mg/kg theophylline intravenously (i.v.) and plasma theophylline concentrations were measured for 12 h thereafter including one exactly 6 h after commencing the i.v. infusion C(6). Pharmacokinetic parameters derived from the plasma concentration-time curve were used to establish DM,CALC for a concentration of 10 micrograms/ml. DM,PRED was obtained from the nomogram using both the optimum and the actual values for C(6). Subsequently oral sustained-release theophylline was administered and the dose adjusted to establish a trough concentration of approximately 10 micrograms/ml. This dose was then corrected arithmetically, assuming a linear relationship between dose and plasma level, to represent that required to achieve a plasma concentration of exactly 10 micrograms/ml (DM,ACT). The correlation between C(6) and log DM,CALC was confirmed (r = 0.97 P less than 0.001), validating the hypothesis. DM,ACT was found to correlate significantly with DM,PRED (r = 0.90, P less than 0.01) substantiating the value of the nomogram. In nine of the 14 patients, DM,ACT corresponded satisfactorily to DM,PRED. In the remaining five, for whom DM,ACT lay outside the 95% confidence limits for the predicted dose, DM,PRED in general underestimated DM,ACT, an advantage in a drug with a low therapeutic index. The predictive error for DM,PRED was lower than that for DM,CALC, and the bias using either method was not significant. The results suggest that a single plasma theophylline assay following a test dose, and the nomogram may be useful in simplifying optimal theophylline administration.

Adult↗
PubMed1983

Investigation of diurnal changes in the disposition of theophylline.

The mechanism of observed temporal variations in plasma theophylline concentrations has been investigated. Eight healthy volunteers were given both oral and intravenous doses of theophylline (5 mg/kg) at 09.00 h and 21.00 h under controlled conditions. Regular plasma concentration measurements were made following each dose in order to determine the diurnal and nocturnal disposition of the drug. Plasma theophylline concentrations at 0.5 h following each oral dose were 6.9 +/- 0.8 micrograms/ml, a.m., and 3.9 +/- 0.6 microgram/ml, p.m. (P less than 0.05). Time to peak concentration was 1.69 +/- 0.28 h, a.m.; 2.13 +/- 0.23 h, p.m. (P less than 0.05). Values for ka were not significantly different, however. Overall bioavailability, volume of distribution and systemic clearances, calculated for the 12 h period after each dose, did not differ significantly between day and night. Diurnal variations in theophylline disposition do not appear to be the result of changes in metabolism or excretion, but may reflect minor differences in absorption.

Administration, Oral↗
PubMed1983

Prediction of maintenance oral theophylline dosage using single oral doses in patients with obstructive airways disease.

This study was designed to test whether single oral doses of theophylline, rather than the specified single intravenous infusions, could be used with a nomogram designed to predict the maintenance oral dose necessary to establish plasma theophylline concentrations of 10 micrograms ml (Koup et al., 1979) in patients with obstructive airways disease. A test dose of theophylline (5 mg kg) was administered on two separate occasions as an oral elixir and as an intravenous infusion. Exactly 6 h after each test dose, plasma theophylline concentration was measured, and the result used to predict daily maintenance dose requirements. During subsequent oral administration, a sustained-release preparation was given in equally divided 12-hourly doses, and 'steady-state' concentrations were measured at trough. Nineteen patients completed the study, and on doses ranging from 4.2 to 21.1 mg kg-1 day-1, trough concentrations of 5.4 to 15.8 micrograms ml (mean 10.0 +/- 0.7 micrograms ml) were achieved. No significant differences were noted between the dose predictions made following either the oral or the intravenous test doses, and the predictive accuracy using the oral route was not compromised. This would suggest that the test dose of theophylline may be administered orally, instead of intravenously, with this nomogram without reducing its efficiency.

Administration, Oral↗
PubMed1981

Bowenoid papulosis: a review.

Bowenoid papulosis, a disease manifested by clinically benign-appearing papules of the anogenital region, which histologically shows the changes of squamous cell carcinoma in situ, is reviewed. Although the biologic behavior of bowenoid papulosis has not been fully elucidated, conservative therapy is suggested.

Adult↗
PubMed1980

Oxidative transformations of polycyclic aromatic hydrocarbons adsorbed on coal fly ash.

Polycyclic aromatic hydrocarbons adsorbed onto coal fly ash were found to be stabilized against photochemical decomposition. However, a number of adsorbed polycyclic aromatic hydrocarbons will spontaneously oxidize in the absence of light, with those compounds containing a benzylic carbon being particularly susceptible. The decomposition rate appears to be fly ash-dependent.

Air Pollutants↗
PubMed1980

Acral lentiginous melanoma.

Acral lentiginous melanoma (ALM) is a relatively recent addition to the clinicohistopathologic classification of melanomas. This variant constitutes 7 to 9 percent of diagnosed melanomas and is typified by a lentiginous macule occurring on the palm, sole, or in subungual regions. A patient with ALM arising in the subungual area and a review of the relevant literature are presented herein.

Female↗
PubMed1978

Thiazolinone analogues of indolmycin with antiviral and antibacterial activity.

Total synthesis of a series of thiazolinone and thiazolidinone analogues of the antibacterial oxazolinone antibiotic indolmycin is described. The synthetic route involves nucleophilic displacement of mesyloxy and chloro groups from methyl 2-substituted-3-(indol-3-yl)propionates 3 and 4 and butyrate 19 with N-substituted thioureas. The formation of the rearranged chloro esters 29, 43, and 44 from beta(RS,RS)-methyl indolmycenate (27), alpha(RS,SR)-methyl 2-hydroxy-3-(2-methylindol-3-yl)butyrate (39), and alpha-methyl 2-hydroxy-3-(indol-3-yl)valerate (41) supports a reaction mechanism involving neighboring group participation by the indole C-3 carbon during nucleophilic displacement on the beta-carbon of a C-3 substituent. Structure-activity relationships are discussed. Although neither indolmycin nor its diastereoisomer isoindolmycin is antiviral, 2-monoalkylaminothiazolinone analogues have in vitro activity against both RNA viruses and bacteria. The most active compound is the sulfur isostere of indolmycin, and only the levorotatory enantiomer 46, with the same absolute stereochemistry as natural indolmycin, has antimicrobial activity.

Anti-Bacterial Agents↗
PubMed1977

Multicentric reticulohistiocytosis.

Multicentric reticulohistiocytosis is a rare disorder of the skin and joints that possesses distinctive histologic findings. A case is reported from shortly after its onset to a stage of resolution 4 1/2 years later.

Adult↗