Background-Despite limiting elastic recoil and late vascular remodeling after angioplasty, coronary stents remain vulnerable to restenosis, caused primarily by neointimal hyperplasia. Paclitaxel, a microtubule-stabilizing drug, has been shown to inhibit vascular smooth muscle cell migration and proliferation contributing to neointimal hyperplasia. We tested whether paclitaxel-coated coronary stents are effective at preventing neointimal proliferation in a porcine model of restenosis. Methods and Results-Palmaz-Schatz stents were dip-coated with paclitaxel (0, 0.2, 15, or 187 g/stent) by immersion in ethanolic paclitaxel and evaporation of the solvent. Stents were deployed with mild oversizing in the left anterior descending coronary artery (LAD) of 41 minipigs. The treatment effect was assessed 4 weeks after stent implantation.

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The purpose of this work was to characterize the solid-state properties of anhydrous paclitaxel and paclitaxel dihydrate. Paclitaxel I (anhydrous) was suspended in water for 24 h to convert it to paclitaxel.2H2O. Both forms were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). X-ray powder diffraction (XRPD) patterns were obtained at 25, 100, and 195 degrees C. Dissolution profiles of both forms were obtained in water at 37 degrees C over h. DSC of paclitaxel.2H2O showed two endothermic peaks below 100 degrees C, corresponding to dehydration. The resulting solid phase was termed "dehydrated paclitaxel.2H2O". At 168 degrees C, a solid-solid transition was observed in which dehydrated paclitaxel.2H2O was converted to a semicrystalline material called "paclitaxel I/am". The solid-solid transition was followed by melting at 220 degrees C. TGA of paclitaxel.2H2O showed a corresponding biphasic weight loss below 100 degrees C, which was equivalent to the weight of 2 mol of water. DSC of paclitaxel I showed no transitions before melting at 220 degrees C, and no weight loss was observed by TGA. Quenching of paclitaxel I from the melt produced amorphous paclitaxel with a glass transition at 152 degrees C. XRPD confirmed that paclitaxel I, paclitaxel.2H2O, and dehydrated paclitaxel.2H2O had different crystal structures. The X-ray patterns of paclitaxel I and paclitaxel I/am were similar, however the two forms of paclitaxel did not behave identically when analyzed by DSC. The bulk dissolution studies with paclitaxel I showed a rapid increase in concentration to 3 micrograms/mL in 4 h, which decreased to 1 microgram/mL after 12 h, corresponding to the solubility of paclitaxel.2H2O. The solubility of paclitaxel.2H2O was 1 microgram/mL. The data demonstrate the existence of a dihydrate form of paclitaxel that is the stable form in equilibrium with water at 37 degrees C but which dehydrates at temperatures > 45 degrees C.

Conifers possess inducible terpenoid defense systems. These systems are associated with the formation of traumatic resin ducts (TRD) and are underpinned by enhanced gene expression and activity of terpene synthases (TPS), enzymes responsible for oleoresin formation. We first determined that Sitka spruce (Picea sitchensis [Bong.] Carriere) had the capacity for TRD formation by mechanically wounding representative trees. We then proceeded to investigate whether the white pine weevil (Pissodes strobi Peck.), a stem-boring insect, can influence the expression of genes encoding monoterpene synthases (mono-tps) in Sitka spruce. We went on to compare this response with the effects of a simulated insect attack by drill wounding. A significant increase in mono-tps transcript level was observed in the leaders of lateral branches of weevil-attacked and mechanically wounded trees. In this study, weevils induced a more rapid enhancement of mono-tps gene expression. A full-length Sitka spruce mono-tps cDNA (PsTPS2) was isolated, expressed in Escherichia coli, and functionally identified as (Ϫ)-pinene synthase. The recombinant (Ϫ)-pinene synthase catalyzes the formation of (Ϫ)-␣-pinene and (Ϫ)-␤-pinene, both of which are known constituents of stem oleoresin in Sitka spruce and increase in abundance after weevil attack. These data suggest that increased (Ϫ)-pinene synthase gene expression is an important element of the direct defense system deployed in Sitka spruce after insect attack.Oleoresin is a complex mixture of monoterpenes, sesquiterpenes, and diterpene resin acids that provide chemical and physical protection of conifer trees against potential herbivores, stem-boring insects, and pathogens (Berryman, 1972; Bohlmann and Croteau, 1999; Phillips and Croteau, 1999; Trapp and Croteau, 2001). In Sitka spruce (Picea sitchensis [Bong.] Carrière), constitutive oleoresin is sequestered in preformed resin ducts in bark, sapwood, and needles. During the initial stages of attack by stem-boring insects, such as weevils (Curculionidae) or bark beetles (Coleopterae), this oleoresin is released and repels insects through intoxication or the formation of physical barriers. Conifers also possess inducible terpenoid defense systems. These include the formation of new traumatic resin ducts (TRD) in phloem and xylem tissue (Cheniclet, 1987; Alfaro, 1995; Nagy et al., 2000; Alfaro et al., 2002) and a hypersensitive response associated with the accumulation of terpenoids, lignin, and phenolics associated with cells surrounding an attack site (Raffa, 1991; Franceschi et al., 1998). Traumatic resinosis can be induced by a range of stimuli, including mechanical wounding, abiotic stress, insect attack, pathogen invasion, elicitor molecules derived from fungal or plant cell walls, or by treatment of trees with methyl jasmonate (MeJA; Croteau et al., 1987; Lieutier and Berryman, 1988; Nagy et al., 2000; Franceschi et al., 2002; Martin et al., 2002). Recent work with Norway spruce (Picea abies) demonstrated that differentiation of TRD in the d...