Citations

The microtubule-binding protein tau has been implicated in the pathogenesis of Alzheimer's disease and related disorders. However, the mechanisms underlying tau-mediated neurotoxicity remain unclear. We created a genetic model of tau-related neurodegenerative disease by expressing wild-type and mutant forms of human tau in the fruit fly Drosophila melanogaster . Transgenic flies showed key features of the human disorders: adult onset, progressive neurodegeneration, early death, enhanced toxicity of mutant tau, accumulation of abnormal tau, and relative anatomic selectivity. However, neurodegeneration occurred without the neurofibrillary tangle formation that is seen in human disease and some rodent tauopathy models. This fly model may allow a genetic analysis of the cellular mechanisms underlying tau neurotoxicity.

Abstract Purpose: Vinorelbine (Navelbine) is an orally absorbable Vinca with broad antitumor activity. It differs from other Vinca in that it is structurally modified on the catharanthine nucleus and has differential actions on tubulin that render it less neurotoxic than other compounds in this class. We conducted a phase I study of vinorelbine given the activity of Vinca alkaloids in many pediatric tumors. Experimental Design: We evaluated the safety and pharmacokinetics of oral and i.v. vinorelbine administered weekly × 6 in children (age, 2-17 years) with different tumors. Patients with disease involvement in the bone marrow were eligible but were stratified and dose-escalated separately. Oral vinorelbine (week 1) was administered as liquid-filled gelatin capsules at thrice the i.v. dose. Intravenous vinorelbine doses of 24 to 37.5 mg/m2 were administered on weeks 2 to 6. Results: The dose-limiting toxicity in patients without marrow involvement was reversible neutropenia. Common nonhematologic toxicities included ≤ grade 2 nausea/vomiting and increased hepatic transaminases. A higher mean i.v. ClTB was observed (1.75 ± 1.0 L/h/kg) compared with adult reports, with a mean t1/2B of 16.5 ± 9.7 hours. Mean oral bioavailability was 28.5 ± 22.5%. The apparent oral clearance (12.1 ± 13.0 L/h/kg) and volume of distribution (69.4 ± 30.6 L/kg) were substantially higher than in adults given similar oral doses. Conclusions: The maximum tolerated dose in children without bone marrow involvement was 30 mg/m2, similar to that reported in adults, with myelosuppression being the dose-limiting toxicity. Higher plasma clearance resulted in lower area under the plasma concentration-time curves at a given dose compared with that reported in adults.

Abstract Purpose: Gemcitabine is a nucleoside analogue with activity against solid tumors. Gemcitabine metabolic inactivation is catalyzed by cytidine deaminase (CDA) or, after phosphorylation, by deoxycytidylate deaminase (DCTD). We set out to study the pharmacogenomics of CDA and DCTD. Experimental Design: The genes encoding CDA and DCTD were resequenced using DNA from 60 African American and 60 Caucasian American subjects. Expression constructs were created for nonsynonymous coding single nucleotide polymorphisms (cSNP) and reporter gene constructs were created for 5′-flanking region polymorphisms. Functional genomic studies were then conducted after the transfection of mammalian cells. Results: CDA resequencing revealed 17 polymorphisms, including one common nonsynonymous cSNP, 79 A>C (Lys27Gln). Recombinant Gln27 CDA had 66 ± 5.1% (mean ± SE) of the wild-type (WT) activity for gemcitabine but without a significant decrease in level of immunoreactive protein. The apparent Km (397 ± 40 μmol/L) for the Gln27 allozyme was significantly higher than that for the WT (289 ± 20 μmol/L; P < 0.025). CDA 5′-flanking region reporter gene studies showed significant differences among 5′-flanking region haplotypes in their ability to drive transcription. There were 29 SNPs in DCTD, including one nonsynonymous cSNP, 172 A>G (Asn58Asp), in Caucasian American DNA. Recombinant Asp58 DCTD had 11 ± 1.4% of WT activity for gemcitabine monophosphate with a significantly elevated level of immunoreactive protein. No DCTD polymorphisms were observed in the initial 500 bp of the 5′-flanking region. Conclusions: These results suggest that pharmacogenomic variation in the deamination of gemcitabine and its monophosphate might contribute to variation in therapeutic response to this antineoplastic agent.

Purpose The primary goal of this study was to evaluate the feasibility and effectiveness of a structured, multidisciplinary intervention targeted to maintain the overall quality of life (QOL), which is more comprehensive than psychosocial distress, of patients undergoing radiation therapy for advanced-stage cancer. Patients and Methods Radiation therapy patients with advanced cancer and an estimated 5-year survival rate of 0% to 50% were randomly assigned to either an eight-session structured multidisciplinary intervention arm or a standard care arm. The eight 90-minute sessions addressed the five domains of QOL including cognitive, physical, emotional, spiritual, and social functioning. The primary end point of maintaining overall QOL was assessed by a single-item linear analog scale (Linear Analog Scale of Assessment or modified Spitzer Uniscale). QOL was assessed at baseline, week 4 (end of multidisciplinary intervention), week 8, and week 27. Results Of the 103 participants, overall QOL at week 4 was maintained by the patients in the intervention (n = 49), whereas QOL at week 4 significantly decreased for patients in the control group (n = 54). This change reflected a 3-point increase from baseline in the intervention group and a 9-point decrease from baseline in the control group (P = .009). Intervention participants maintained their QOL, and controls gradually returned to baseline by the end of the 6-month follow-up period. Conclusion Although intervention participants maintained and actually improved their QOL during radiation therapy, control participants experienced a significant decrease in their QOL. Thus, a structured multidisciplinary intervention can help maintain or even improve QOL in patients with advanced cancer who are undergoing cancer treatment.