Feasibility of discriminating powdery mildew-affected grape berries at harvest using mid-infrared attenuated total reflection spectroscopy and fatty acid profiling

Background and Aims: Powdery mildew (Erysiphe necator) reduces the quality of winegrapes, and objective methods for assessment are required. Mid-infrared spectroscopy and fatty acid analysis were investigated for rapid diagnosis of affected berries. Methods and Results: Colonisation by E. necator reduced berry diameter andmass and increased the surface area : volume ratio. Mid-infrared spectra (1800–1185 cm 1) contained information on E. necator and compounds related to infection, but spectral similarity of visually healthy and partly infected berries confounded differentiation between these groups. Fatty acids in E. necator and berries were identified and quantified by gas chromatography. Six saturated even-chain fatty acids were prevalent in E. necator, arachidic acid being most abundant. Following stepwise linear discriminant analysis, four saturated fatty acids distinguished 97% of healthy berries and assigned approximately 75% of partly and fully infected berries to their original groups. Arachidic acid concentration,which changed amongst healthy, partly and fully infected berries (P = 0.001), correctly classified90% of healthy berries. Conclusions: Analysis of fatty acids allowed discrimination of healthy and infected berries whereas mid-infrared spectroscopy proved less informative. Arachidic acid concentration increased with disease severity. Significance of the Study: Fatty acid analysis offers a new approach for objective measurement of powdery mildew. Arachidic acid is proposed as a biomarker for powdery mildew on grapes

The Relationship Between Cardiac Troponin in People Hospitalised for Exacerbation of COPD and Major Adverse Cardiac Events (MACE) and COPD Readmissions

Background: No single biomarker currently risk stratifies chronic obstructive pulmonary disease (COPD) patients at the time of an exacerbation, though previous studies have suggested that patients with elevated troponin at exacerbation have worse outcomes. This study evaluated the relationship between peak cardiac troponin and subsequent major adverse cardiac events (MACE) including all-cause mortality and COPD hospital readmission, among patients admitted with COPD exacerbation. Methods: Data from five cross-regional hospitals in England were analysed using the National Institute of Health Research Health Informatics Collaborative (NIHR-HIC) acute coronary syndrome database (2008–2017). People hospitalised with a COPD exacerbation were included, and peak troponin levels were standardised relative to the 99th percentile (upper limit of normal). We used Cox Proportional Hazard models adjusting for age, sex, laboratory results and clinical risk factors, and implemented logarithmic transformation (base-10 logarithm). The primary outcome was risk of MACE within 90 days from peak troponin measurement. Secondary outcome was risk of COPD readmission within 90 days from peak troponin measurement. Results: There were 2487 patients included. Of these, 377 (15.2%) patients had a MACE event and 203 (8.2%) were readmitted within 90 days from peak troponin measurement. A total of 1107 (44.5%) patients had an elevated troponin level. Of 1107 patients with elevated troponin at exacerbation, 256 (22.8%) had a MACE event and 101 (9.0%) a COPD readmission within 90 days from peak troponin measurement. Patients with troponin above the upper limit of normal had a higher risk of MACE (adjusted HR 2.20, 95% CI 1.75–2.77) and COPD hospital readmission (adjusted HR 1.37, 95% CI 1.02–1.83) when compared with patients without elevated troponin. Conclusion: An elevated troponin level at the time of COPD exacerbation may be a useful tool for predicting MACE in COPD patients. The relationship between degree of troponin elevation and risk of future events is complex and requires further investigation