Coronary-artery thrombi play an important part in the pathogenesis of unstable angina and acute myocardial infarction. However, the appearance of the thrombi is different in the two conditions, possibly reflecting differences in the composition of age of the thrombi or the presence or absence of blood flow in the artery. This difference may account for the contrasting results of thrombolytic therapy.

Abstract-Vulnerable plaque generally contains a thin fibrous cap, lipid pools, and reduced internal plaque collagen.Arterial fluorescence analysis can differentiate atherosclerotic lesions from normal arteries; however, the contribution of the lipid core to atherosclerotic arterial fluorescence remains controversial. This study aimed to identify lipid core fluorophores and to differentiate the lipid core from normal artery and atheroma. The helium-cadmium laser-induced fluorescence spectra of cadaveric arteries and known chemical constituents were recorded. Lipid core fluorescence spectra exhibited marked red shifts and broadening compared with the fluorescence spectra of normal tissue and atheroma. Similar fluorescence spectra were obtained for lipid core and oxidized low density lipoprotein, for atheroma and collagen, and for normal artery and elastin. A classification based on collagen, elastin, and oxidized low density lipoprotein spectral decomposition could discriminate the lipid core (nϭ29), normal artery (nϭ74), atheroma (nϭ73), and preatheroma (nϭ10) A theromatous plaque consists of a lipid-rich core covered with a collagen-rich fibrous cap, varying widely in thickness. Plaque disruption is associated with varying degrees of internal hemorrhage and luminal thrombosis because the lipid core and exposed collagen are thrombogenic. 1 Acute coronary syndrome usually occurs as a consequence of such disruption or ulceration of vulnerable plaque. Vulnerable plaque is characterized by lipid pools, a thin fibrous cap, and reduced internal plaque collagen. 2-8 The ability to characterize plaque and detect vulnerable plaque would contribute to the treatment of plaque and prevention of acute coronary syndrome.Laser-induced fluorescence spectroscopy of the cardiovascular system has been used not only to identify atheroma but also to measure intimal thickness. Many classification indexes for differentiating plaque types and measuring intimal thickness have been derived from empirical studies of fluorescence spectra. 9 -14 Therefore, understanding the nature of arterial fluorophores 15-18 is important for accurate classification of arterial tissues. A classification algorithm 15 based on fluorescence spectral decomposition of elastin and collagen can be used to discriminate between normal and atherosclerotic arterial tissues. Knowing the major fluorophores of the lipid core is essential for identifying vulnerable plaque. Fluorescence intensities of 500 and 600 nm characterize fatty plaque 11 ; whether the lipid core (lipids) contributes to atherosclerotic and normal arterial fluorescence is controversial.The present study was undertaken to (1) observe laserinduced fluorescence spectra from normal artery, atheromatous plaque, and ulcerated plaque (lipid core); (2) clarify the fluorophores of the lipid core and derive a classification algorithm to distinguish these 3 tissue types on the basis of arterial fluorophores; and (3) characterize changes in fluorescence spectra during fibrous cap removal and estimate fibrous ca...

We investigated the effects of fluorescent illumination with a high red-to-far-red ratio (R:FR) on the resistance of cucumber (Cucumis sativus) seedlings to powdery mildew fungus (Sphaerotheca cucurbitae; PM). Seedlings were grown at a photosynthetic photon flux (PPF) of 300 μmol·m−2·s−1 provided by fluorescent lamps with high R:FR light (R:FR = 7.0; FLH) or low R:FR light (R:FR = 1.1; FLL) until cotyledons or the first foliage leaf were fully expanded. Spores of PM were then inoculated onto the leaves, and the seedlings were grown for 7 days (from cotyledon stage) or 9 days (from foliage–leaf stage) under FLH. The number of PM colonies on FLH seedlings was 0.80× (cotyledons) and 0.62× (foliage leaves) the number on FLL seedlings. The reduction on the FLH seedlings was probably the result of changes in leaf morphological characteristics such as a thicker epidermal tissue as a result of the higher R:FR illumination. The number of PM colonies on cotyledons of the FLH seedlings was also smaller than that on seedlings grown under metal-halide lamps providing a spectrum similar to that of natural light (R:FR = 1.2).

To evaluate the effect of fluorescent lamps with a high red:far-red (R:FR) light on the potential photosynthesis of transplants, we investigated the photosynthetic light responses of cucumber (Cucumis sativus L.) seedlings grown under fluorescent lamps with high R:FR light (FLH) and compared them with the responses of the seedlings grown under metal-halide lamps (ML) that provided a spectrum similar to that of natural light and under a fluorescent lamp with low R:FR light (FLL). The seedlings were grown under FLH (R:FR = 7.0), ML (R:FR = 1.2), or FLL (R:FR = 1.1) at a photosynthetic photon flux density (PPFD) of 350 μmol·m−2·s−1. The gross photosynthetic rate (Pg), quantum yield of photosystem II (ΦPSII), and photosynthetic electron transfer rate (ETR) of the foliage leaves were then evaluated at PPFDs ranging from 0 to 1000 μmol·m−2·s−1. The photosynthetic light response of FLH seedlings was similar to those of sun leaves, and the responses of ML and FLL seedlings were similar to those of shade leaves. The Pg, ETR, and ΦPSII of FLH seedlings at PPFD of 1000 μmol·m−2·s−1 was 1.38, 1.32, and 1.28 times, respectively, those of ML seedlings, and was 1.40, 1.23, and 1.22 times, respectively, those of FLL seedlings. The Pg was closely correlated with ETR in each treatment. FLH seedlings had thicker leaf and greater chlorophyll content per leaf area than ML and FLL seedlings. The greater Pg of FLH seedlings than in the other two groups of seedlings at high PPFD was probably the result of the improved ETR resulting from physiological and morphological changes in response to the high R:FR light.

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