SummaryExperiments have shown that many phenylpropanoid genes are highly expressed in light-grown Arabidopsis roots. Studies employing reporter gene constructs have indicated that the expression of these genes is localized not only to the lignifying root vasculature, but also to non-lignifying tissues, such as the root cortex, suggesting that the proteins encoded by these genes may be involved in aspects of phenylpropanoid metabolism other than ligni®cation. Consistent with this hypothesis, roots of etiolated and soil-grown plants contain almost no soluble phenylpropanoids, but exposure to light leads to the accumulation of avonoids, as well as high levels of coniferin and syringin (coniferyl and sinapyl-4-O-glycosides), compounds not previously reported to be accumulated in Arabidopsis. To elucidate the mechanism by which light induces root secondary metabolism, extracts of mutants defective in light perception and light responses were analyzed for phenylpropanoid content. The results of these assays showed that phytochrome (PHY)B and cryptochrome (CRY)2 are the primary photoreceptors involved in light-dependent phenylpropanoid accumulation, and that the hypocotyl elongated (HY5) transcription factor is also required for this response. The presence of phenylpropanoids in etiolated roots of cop (constitutively photomorphogenic)1, cop9, and det (de-etiolated)1 mutants indicate that the corresponding wild-type genes are required to repress root phenylpropanoid biosynthesis in the absence of light. Biochemical analysis of root cell walls and analysis of phenylpropanoid gene expression suggest that coniferin and syringin accumulation may be the result of both increased biosynthesis and decreased conversion of these compounds into other phenylpropanoid end products. Finally, our data suggest that the accumulation of coniferin, syringin, and avonoids in Arabidopsis roots is a high-irradiance response (HIR), and suggest that comparative analysis of light-and dark-grown Arabidopsis roots may provide new insights into both phenylpropanoid biosynthesis and light signaling in plants.

Purpose We sought to characterize the pharmacokinetics (PK) and determine a tolerable dose of oral sorafenib in patients with hepatic or renal dysfunction. Patients and Methods Patients were assigned to one of nine cohorts: cohort 1, bilirubin ≤ upper limit of normal (ULN) and AST ≤ ULN and creatinine clearance (CC) ≥ 60 mL/min; cohort 2, bilirubin more than ULN but ≤ 1.5× ULN and/or AST more than ULN; cohort 3, CC between 40 and 59 mL/min; cohort 4, bilirubin more than 1.5× ULN to ≤ 3× ULN (any AST); cohort 5, CC between 20 and 39 mL/min; cohort 6, bilirubin more than 3× ULN to 10× ULN (any AST); cohort 7, CC less than 20 mL/min; cohort 8, albumin less than 2.5 mg/dL (any bilirubin/AST); and cohort 9, hemodialysis. Sorafenib was administered as a 400-mg dose on day 1 for PK, and continuous daily dosing started on day 8. Results Of 150 registered patients, 138 patients were treated. With the exception of cohorts 6 and 7, at least 12 patients per cohort were assessable, and the dose level with prospectively defined dose-limiting toxicity in less than one third of patients by day 29 was considered tolerable. No significant associations between the sorafenib PK and cohort were found. Conclusion We recommend the following empiric sorafenib starting doses by cohort: cohort 1, 400 mg twice a day; cohort 2, 400 mg twice a day; cohort 3, 400 mg twice a day; cohort 4, 200 mg twice a day; cohort 5, 200 mg twice a day; cohort 6, not even 200 mg every third day tolerable; cohort 7, not defined; cohort 8, 200 mg each day; and cohort 9, 200 mg each day.