Enzymatic cyclization of geranylgeranyl diphosphate to fusicoccadiene involves a transannular proton transfer process. Label distribution in the cyclized products derived from deuterium-labeled GGDPs showed that a proton generated from C-10 migrates to C-6 in the intermediary dolabellane framework prior to the second ring formation. Although a direct 1,5-proton transfer would achieve this process, semiempirical MO calculations suggested an alternative pathway, which involves successive 1,4- and 1,5-proton transfers using C-2 as a springboard.

Solid-state photochromism of benzopyrans and naphthopyrans (chromenes) was investigated in the temperature range between 300 and 80 K. Variable-temperature diffuse reflectance spectroscopy of microcrystalline powders showed that the extent of photocoloration was greatly enhanced at low temperatures. All the chromenes examined exhibited solid-state photochromism at low temperatures, even when they showed little or no photocoloration at room temperature. The solid-state photochromic properties of the chromenes were quite similar to those reported for analogous photochromic compounds of spiropyrans and spirooxazines, which indicates that these classes of compounds are generally photochromic even in the solid state. Photobleaching reactions of the colored merocyanine forms proceeded at low temperatures through the formation of a colorless intermediate, instead of directly resuming the original closed form. In addition to two stable planar merocyanine forms, which are usually observed in the photochromic reactions in solution, photoreactions at low temperatures allowed us to observe unstable colored species, which were tentatively assigned as nonplanar cisoid forms, and were stabilized in the solid state at low temperatures.

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Background/Aim: We conducted a prospective exploratory study to investigate the relationship between radiation pneumonitis (RP) and transforming growth factor-β1 (TGF-β1) in exhaled breath condensate (EBC). Patients and Methods: The inclusion criteria were: patients who 1) received thoracic radiotherapy (RT) for lung cancer, 2) were aged ≥20 years, and 3) provided written informed consent. EBC was collected before and 1 month after RT. TGF-β1 levels in EBC were measured using an enzyme-linked immunosorbent assay. We evaluated RP using the Common Terminology Criteria for Adverse Events v4 and analyzed the relationship between grade (G) 2 RP and TGF-β1 levels in EBC. Results: Ten patients were enrolled [median age, 75 years (range=60-81 years)], and none of them had interstitial lung disease. Conventional fractionation, accelerated hyperfractionation, hypofractionation, and stereotactic ablative fractionation were used in four, one, two, and three patients, respectively. G1 and G2 RP were observed in five patients each; no G3-G5 RP occurred. The median TGF-β1 levels in EBC before and 1 month after RT were 79.1 pg/ml (0.1-563.7 pg/ml) and 286.9 pg/ml (33.7-661.3 pg/ml), respectively. Of the seven patients with increased TGF-β1 levels in EBC 1 month after RT than before RT, five (71%) experienced G2 RP, whereas the remaining three patients with decreased TGF-β1 levels had G1 RP (p=0.083,. Conclusion: Increased TGF-β1 levels in EBC 1 month after RT might be promising for the detection of G2 RP.Patients. This prospective study (clinical trial registration number: UMIN000040894) was approved by the Institutional Ethics Committee (approval number: H30-094). The inclusion criteria were as follows: patients who 1) received thoracic RT for lung cancer, 2) 1485