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Biomedical subjects

J C Stewart

Publications and source records attributed to J C Stewart.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Determination of 5,10,15,20-tetra-(m-hydroxyphenyl)chlorin in human plasma by high performance liquid chromatography.

A high performance liquid chromatographic method for the determination of the photodynamic chemotherapeutic agent 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (m-THPC) in human plasma following intravenous infusion is described. The procedure involves extraction of the drug in plasma with methanol/dimethyl sulphoxide (4:1 v/v) containing 5,10,15,20-tetra(p-hydroxyphenyl)chlorin as the internal standard and separation on a C18 reversed phase column with acetonitrile:0.1% trifluoroacetic acid (77:23 v/v) as the mobile phase. The drug was detected specifically and sensitively at its absorption maximum of 423 nm with a detection limit of 15 ng/mL (signal-to-noise ratio of 5). The intra- and inter-assay coefficients of variation (CV) on analysis of a plasma spiked with m-THPC (1 micrograms/mL) were 2.3 and 3.4% (n = 6), respectively.

Antineoplastic Agents↗
PubMedDate not supplied

Determination of 5,10,15,20-tetra-(m-hydroxyphenyl)chlorin in tissues by high performance liquid chromatography.

A procedure for the extraction and high performance liquid chromatographic (HPLC) determination of the photodynamic therapeutic agent 5,10,15,20-tetra(m-hydroxyphenyl)chlorin in human, rat and mouse tissues following intravenous administration of the drug is described. The tissue (tumour, skin, muscle and liver) was homogenized and extracted into a mixture of methanol:dimethyl sulphoxide:water (32:8:1 by vol.) containing, 5,10,15,20-tetra(p-hydroxyphenyl)chlorin as the internal standard. The precipitated proteins were removed by centrifugation and the supernatant was separated by reversed phase HPLC on a Hypersil-ODS column with 77% (v/v) acetonitrile in 0.1% trifluoroacetic acid as the mobile phase. The solute was detected with high sensitivity and specificity by a UV-VIS detector set at 423 nm.

Animals↗
PubMedDate not supplied

Enhancing services for offenders: the impact on treatment completion.

Because of high drop out rates, it is important to determine if enhancing standard substance treatment services will impact treatment completion rates among those in need of specialized services who are involved in the criminal justice system. The purpose of this research was to understand the impact of providing mental health services and gender-specific services for women in a modified therapeutic community setting. In the study, those who received mental health services and/or gender-specific treatment services, in additional to the substance abuse services, had similar rates of treatment completion as compared to those who received only substance abuse services. Logistic regression results indicated that controlling for other variables, age and length of time using one's primary drug were the only statistically significant predictors of treatment completion. The results suggest that the treatment model described in this article is a potentially cost-effective method of maximizing existing resources for treating substance abusing criminal offenders in community-based treatment settings.

Adolescent↗
PubMedDate not supplied

Interspecies comparison of acivicin pharmacokinetics.

Pharmacokinetic studies with the amino acid antineoplastic agent, acivicin, were carried out in the Sprague-Dawley rat, cynomolgus monkey, and beagle dog. Data were analyzed together with previously published studies in the mouse and rhesus monkey. Log-log plots of body weight (B, kg) versus total body clearance (ClB, ml/min), elimination half-life (t1/2, hr), and volume of distribution (V, ml) in the five species were linear with high correlation coefficients (r greater than or equal to 0.98) despite large differences in the extent of nonrenal clearance in the various species (ranging from approximately 30% of the dose in the mouse to 90% in the dog). Linear regression on the plots yielded allometric expressions (ClB = 4.0 x B0.62; t1/2 = 1.8 x B0.31; V = 620 x B0.95) which were extrapolated mathematically to predict acivicin pharmacokinetic parameters in humans prior to the first clinical trials. Predicted versus measured (mean +/- SD, N = 21 patients) pharmacokinetic values in humans were: ClB (ml/min), 50 vs. 49 +/- 13; t1/2 (hr), 6.4 vs. 9.5 +/- 3.5; VB (ml/kg), 500 vs. 580 +/- 110. Thus, the animal data were successfully extrapolated to yield reasonable predictions of human pharmacokinetic parameters, despite varying extents of renal and nonrenal clearance in the species examined. With one exception, plasma concentration-time data in six species spanning a 3000-fold body weight range and a 120-fold dose range were plotted on a single curve after plasma concentrations were normalized for the dose administered and chronological times were adjusted for body weight to yield "physiological times."(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗