PubMed Health⌕ Search

Biomedical subjects

Denise Adams

Publications and source records attributed to Denise Adams.

7 recordsLinked to original sources
PubMed2006

Transition from meeting abstract to full-length journal article for randomized controlled trials.

CONTEXT: Not all research presented at scientific meetings is subsequently published and, even when it is, there may be inconsistencies between these results and what is ultimately printed. Although late-breaking trials sessions are now integrated into several major scientific meetings and the results are often promptly and prominently communicated, no studies have examined the publication fate and degree of consistency between meeting abstracts or presentations and subsequent full-length article publications for randomized controlled trials (RCTs) presented at these sessions. OBJECTIVE: To compare RCT abstracts presented in the late-breaking trials session vs other sessions at a major scientific meeting and subsequent full-length publications. DESIGN: RCTs were identified by hand searching abstract proceedings booklets and related Web sites for the American College of Cardiology scientific meetings (1999-2002). Subsequent full-length articles were identified via electronic databases. MAIN OUTCOME MEASURES: Publication fate and degree of consistency between meeting abstract results and subsequent full-length publication results. RESULTS: The 86 late-breaking RCTs were significantly larger (median, 2737 patients vs 896; P<.001), were more likely to be preceded by a published design paper (27 [31%] vs 13 [13%]; P = .002), had higher quality scores when eventually published (mean Jadad score 2.69 vs 2.19; P = .01), and were less likely to report favorable results for the intervention than the 100 randomly chosen comparison RCTs presented in other sessions (50 [58%] vs 75 [75%]; P = .01; odds ratio 0.46; 95% confidence interval, 0.24-0.90). RCTs presented at the late-breaking trials sessions were significantly more likely to be published (79 [92%] vs 69 [69%]; P<.001) and appeared earlier after presentation (median 11.5 months vs 22.0 months; P<.001) than RCTs presented in other sessions, an association that persisted even after adjusting for sample size, conclusion of study, and RCT design: adjusted hazard ratio, 1.80 (95% confidence interval, 1.24-2.61). Sixty (41%) of the 148 RCTs that were subsequently published exhibited discrepancies between the efficacy estimate reported in the meeting abstract vs the one reported in the full-length article for the primary outcome. The mean change in effect was 0.44 SDs and in 20 cases (14%), the point estimate was statistically significant in only 1 member of the pair. The discrepancy rate was the same for late-breaking RCTs as for RCTs presented in other American College of Cardiology sessions (P = .92). CONCLUSIONS: Late-breaking trials were larger, more likely to be preceded by a design paper, and less likely to report positive results than RCTs presented at other sessions, but discrepancies between the meeting abstract results and subsequent full-length publication results were common even for late-breaking trials.

Abstracting and Indexing↗
PubMed2006

Cyclophosphamide disposition in an anephric child.

Although limited data are available about cyclophosphamide disposition in patients with renal insufficiency, nothing has been reported in anephric patients. We characterized cyclophosphamide pharmacokinetics in an anephric child with bilateral Wilms tumor, both on (day 1) and off (day 2) hemodialysis. The median cyclophosphamide clearance on and off hemodialysis was 5.34 and 3.82 L/hr*m(2), respectively, demonstrating elimination of cyclophosphamide in this anephric child. The off hemodialysis clearance was similar to that in children with normal renal function. Hydroxycyclophosphamide (HCY) AUC was 20.6 and 8.77 microM*hr on and off hemodialysis. Carboxyethylphosphoramide mustard (CEPM) AUC obtained on hemodialysis (i.e., 194 microM*hr) was similar to that in children with normal renal function, although an elevated CEPM AUC was observed when hemodialysis was not received (i.e., 383 microM*hr). With the recent findings that clinical outcomes are related to CEPM AUC, further data are needed regarding the pharmacokinetics of cyclophosphamide and relevant metabolites in anephric children.

Antineoplastic Agents, Alkylating↗
PubMed2004

Pharmacokinetics of O(6)-benzylguanine in pediatric patients with central nervous system tumors: a pediatric oncology group study.

PURPOSE: To report the results of the first pharmacokinetic study in pediatric patients of O(6)-benzylguanine (O(6)BG), which irreversibly inactivates the DNA repair protein alkylguanine-alkyltransferase, thus enhancing the cytotoxicity of nitrosoureas. EXPERIMENTAL DESIGN: As part of a Pediatric Oncology Group Phase I study, 120 mg/m(2) of O(6)BG was administered i.v. over 1 h, before 1,3-bis(2-chloroethyl)-1-nitrosourea administration in children with recurrent or refractory brain tumors. Serial blood samples for plasma pharmacokinetic studies were obtained. Concentrations of O(6)BG and its active metabolite O(6)-benzyl-8-oxoguanine (8-oxo-O(6)BG) were measured by high-performance liquid chromatography. A pharmacokinetic model and additional first-order elimination rate constants for each compound were developed. RESULTS: O(6)BG concentration versus time data were evaluated for 25 patients. The peak concentration of O(6)BG (mean +/- SD) was 11 +/- 4 microm, and the peak concentration of its active metabolite, 8-oxo-O(6)BG, was 35 +/- 10 microm. O(6)BG was rapidly eliminated with a half-life of 85 +/- 140 min, area under the curve of 795 +/- 320 microm. min and clearance of 760 +/- 400 ml/min/m(2). The area under the curve of 8-oxo-O(6)BG when extrapolated to infinity was 22,700 +/- 11,800 microm. min. The clearance and terminal half-life of 8-oxo-O(6)BG were 30 +/- 15 ml/min/m(2) and 360 +/- 220 min, respectively. CONCLUSIONS: There is rapid elimination of O(6)BG after i.v. administration over 1 h. In contrast, the terminal half-life for the active metabolite, 8-oxo-O(6)BG, is 4-fold longer. The pharmacokinetic parameters for O(6)BG and 8-oxo-O(6)BG are similar to those reported previously in adults.

Adolescent↗
PubMed2004

Topotecan disposition in an anephric child.

Although limited data are available about topotecan disposition in patients with renal insufficiency, nothing has been reported in anephric patients. The objective of this report is to characterize topotecan disposition in an anephric child with Wilms tumor, both on and off hemodialysis. The patient received topotecan and cyclophosphamide for four cycles; topotecan was administered daily for 5 days, with hemodialysis on the second and fourth day. Therapy was well tolerated, with grade 3 thrombocytopenia and grade 2 neutropenia noted after cycle four. The median topotecan lactone clearance was 15.5 L/h/m off hemodialysis and 18.7 L/h/m on hemodialysis. Topotecan clearance was minimally affected by hemodialysis and was similar to that observed in children without renal failure.

Antineoplastic Agents↗
PubMed2002

Solution structure of mu-conotoxin PIIIA, a preferential inhibitor of persistent tetrodotoxin-sensitive sodium channels.

Mu-conotoxins are peptide inhibitors of voltage-sensitive sodium channels (VSSCs). Synthetic forms of mu-conotoxins PIIIA and PIIIA-(2-22) were found to inhibit tetrodotoxin (TTX)-sensitive VSSC current but had little effect on TTX-resistant VSSC current in sensory ganglion neurons. In rat brain neurons, these peptides preferentially inhibited the persistent over the transient VSSC current. Radioligand binding assays revealed that PIIIA, PIIIA-(2-22), and mu-conotoxins GIIIB discriminated among TTX-sensitive VSSCs in rat brain, that these and GIIIC discriminated among the corresponding VSSCs in human brain, and GIIIA had low affinity for neuronal VSSCs. (1)H NMR studies found that PIIIA adopts two conformations in solution due to cis/trans isomerization at hydroxyproline 8. The major trans conformation results in a three-dimensional structure that is significantly different from the previously identified conformation of mu-conotoxins GIIIA and GIIIB that selectively target TTX-sensitive muscle VSSCs. Comparison of the structures and activity of PIIIA to muscle-selective mu-conotoxins provides an insight into the structural requirements for inhibition of different TTX-sensitive sodium channels by mu-conotoxins.

Amino Acid Sequence↗