Oxidations in white grape (Vitis vinifera L.) skins: Comparison between ripening process and photooxidative sunburn symptoms.

Oxidations in grape berries are gaining major interest as they affect grape characteristics and quality. Considering berries, Reactive Oxygen Species are involved in the responses to both ripening process and stresses, including photooxidative sunburn. Redox metabolism involves a multitude of chemical and enzymatic reactions. In this study, four white grape cultivars were examined for natural ripening and photooxidative sunburn effects (obtained in artificial conditions) on berry pigmentation, chemical composition and enzymatic activity. The measured parameters included reflectance spectra, pigmentation (including berry browning), content of photosynthetic pigments, organic acid profiles, antioxidant activity, concentrations of antioxidants (total phenolics, ascorbic acid and reduced glutathione), enzymatic activities (guaiacol peroxidases, ascorbate peroxidase and catalase). The effects of the treatment (natural ripening and artificial photooxidative sunburn) on each considered parameter are described in the paper. Photooxidative sunburn strongly affected the contents of antioxidants and chlorophylls, increased the browning index and modulated the enzymatic activities investigated. Samples clearly clustered depending on the oxidation status. Furthermore, the PCA highlighted the similarities and differences in the responses to oxidative stress during ripening and photooxidative sunburn. PCA produced five functions with eigenvalues higher than 1, representing 87.03% of the total variability. In particular, the scores of the function 1 discriminated the samples based on the oxidation status, while the function 2 separated the samples based on the sampling date, representing the physiological responses characteristic of ripening. Our work sheds light on this topic, and will allow a more conscious vineyard management, thus supporting the agricultural adaptation to climate changes.

Acute spontaneous aortic pathologies associated with intramural hematoma: can a differential diagnosis be made by imaging techniques?

Acute intramural aortic hematoma may result from ruptured vasa vasorum without intimal disruption (IMH hereafter) but can also be found in association with processes in which an intimal lesion is present, such as aortic dissections (AD), where the hematoma represents the acute thrombosis of the false lumen, or in penetrating atherosclerotic ulcers (PAU), where blood collects beyond the disrupted internal elastic lamina. As the clinical presentation of these conditions is very similar, imaging techniques should aim both to diagnose the hematoma and to characterize the underlying pathology. This review critically analyzes the diagnostic potential of several imaging methods based on personal experience and literature reports. Although intramural hematoma can be easily diagnosed unrespective of the tomographic imaging modality, it is usually difficult to distinguish between IMH and hematomas associated either to AD or to PAU. Indeed, only PAU related hematomas can be consistently diagnosed due to the high probability of unveiling the causative wall ulceration; conversely, the differential diagnosis between IMH and AD - associated hematomas is still matter of controversy. According to the literature, the two conditions cannot be differentiated by transesophageal echocardiography, though some reports state that a distinction might be made by MR imaging. As regards CT, only a small percentage of AD - associated hematomas exhibit clear evidence of a typical intimal flap, allowing for a safe diagnosis to be made: often, unfortunately, the intimal lesion subsequently found at surgery cannot be detected, yielding a picture of IMH. Therefore, the radiological report should give the same diagnostic probability to both conditions.