The substitution pattern of anthocyanin pigments is a main determinant of f lower color. Flavonoid 3,5-hydroxylase (F35H) is a cytochrome P450 enzyme (Cyt P450) that catalyzes the 3,5-hydroxylation of dihydrof lavonols, the precursors of purple anthocyanins. Species such as rose and carnation lack F35H activity and are, therefore, unable to generate purple or blue f lowers. Petunia, on the other hand, contains two loci, termed hf1 and hf2, that encode a Cyt P450 with F35H activity. Here we report the identification of an additional petunia gene that is required for 3,5 substitution of anthocyanins and purple f lower colors. It encodes a cytochrome b 5 and is expressed exclusively in the f lower. Inactivation of the gene by targeted transposon mutagenesis reduced F35H enzyme activity and the accumulation of 5-substituted anthocyanins, resulting in an altered f lower color. However, no phenotypic effect on the activity of other Cyt P450s, involved in the synthesis of hormones or general phenylpropanoids, was observed. These data provide in vivo evidence for the regulation of the activity of specific Cyt P450s by a cytochrome b 5 .

A new quantitative parameter, diffuse index (DI), was proposed to evaluate objectively whether in-stent restenosis is diffuse or focal in nature. A total of 343 patients (346 lesions) with Wiktor-GX, AVE MS-II, or JOMED stents were evaluated at follow-up angiography. According to the QCA-CMS definition, lesion length is derived from the 100% reference diameter function (RDF). By moving the RDF downward, the lesion length, LL(x), at each percentage x of the RDF can be calculated. We have defined the DI by the ratio of this calculated length LL(x) and the total stent length, SL, in other words, DI = [LL(x)/SL]. The percentage plaque area (% PA) was calculated by dividing the plaque area by the sum of the plaque area and luminal area within the stent. An excellent correlation was found between the DI at 88% RDF and the % PA in all three stents (r> 0.88). The individual correlation curves were nearly identical, independent of the type of stent. Furthermore, based on the overall data, the combination of a DI > 0.8 and % PA > 30% correlated with a high incidence of subsequent major adverse cardiac events (13/25 = 52%). From these data, it can be concluded that the diffuse index is a new objective quantitative parameter to describe whether in-stent restenosis is of focal or diffuse nature.