Evaluation of Modern Approaches for the Assessment of Dietary Carotenoids as Markers for Fruit and Vegetable Consumption.

The assessment of dietary carotenoids via blood measurements has been widely used as a marker for fruit and vegetable consumption. In the present study, modern, non-invasive approaches to assess dietary carotenoids, such as skin measurements and an app-based short dietary record (ASDR), were compared with conventional methods such as plasma status and handwritten 3-day dietary records. In an 8-week observational study, 21 healthy participants aged 50-65 years recorded their daily consumption of carotenoid-rich fruits and vegetables via a specially developed ASDR. Anthropometry, blood samplings and assessment of skin carotenoids via Raman and reflection spectroscopy were performed at baseline, after four weeks and at the end of the study. App-based intake data showed good correlations with plasma α-carotene (r = 0.74, p < 0.0001), ß-carotene (r = 0.71, p < 0.0001), and total plasma carotenoids (r = 0.65, p < 0.0001); weak correlations with plasma lutein/zeaxanthin and ß-cryptoxanthin (both r = 0.34, p < 0.05); and no correlation with plasma lycopene. Skin measurements via reflection and Raman spectroscopy correlated well with total plasma carotenoids (r = 0.81 and 0.72, respectively; both p < 0.0001), α-carotene (r = 0.75-0.62, p < 0.0001), and ß-carotene (r = 0.79-0.71, p < 0.0001); moderately with plasma lutein/zeaxanthin (both r = 0.51, p < 0.0001); weakly with plasma ß-cryptoxanthin (r = 0.40-0.31, p < 0.05); and showed no correlation with plasma lycopene. Skin measurements could provide a more convenient and noninvasive approach of estimating a person's fruit and vegetable consumption compared to traditional methods, especially in studies that do not intend blood sampling. ASDR records might function as a suitable, convenient tool for dietary assessment in nutritional intervention studies.

In vivo detection of changes in cutaneous carotenoids after chemotherapy using shifted excitation resonance Raman difference and fluorescence spectroscopy.

BACKGROUND: Various cutaneous toxicities under chemotherapy indicate a local effect of chemotherapy by secretion after systemic application. Here, changes in the fluorescence and Raman spectral properties of the stratum corneum subsequent to intravenous chemotherapy were assessed. METHODS: Twenty healthy subjects and 20 cancer patients undergoing chemotherapy were included. Measurement time points in cancer patients were before the first cycle of chemotherapy (Tbase ) and immediately after intravenous application of the chemotherapy (T1 ). Healthy subjects were measured once without any further intervention. Measurements were conducted using an individually manufactured system consisting of a handheld probe and a wavelength-tunable diode laser-based 488 nm SHG light source. Hereby, changes in both skin fluorescence and shifted excitation resonance Raman difference spectroscopy (SERRDS) carotenoid signals were assessed. RESULTS: Healthy subjects showed significantly (P < .001) higher mean concentrations of carotenoids compared to cancer subjects at Tbase . An increase in fluorescence intensity was detected in almost all patients after chemotherapy, especially after doxorubicin infusion. Furthermore, a decrease in the carotenoid concentration in the skin after chemotherapy was found. CONCLUSION: The SERRDS based noninvasive detection can be used as an indirect quantitative assessment of fluorescent chemotherapeutics. The lower carotenoid SERRDS intensities at Tbase might be due to cancerous diseases and co-medication.

The evaluation of NIR-absorbing porphyrin derivatives as contrast agents in photoacoustic imaging.

Six free base tetrapyrrolic chromophores, three quinoline-annulated porphyrins and three morpholinobacteriochlorins, that absorb light in the near-IR range and possess, in comparison to regular porphyrins, unusually low fluorescence emission and (1)O2 quantum yields were tested with respect to their efficacy as novel molecular photo-acoustic imaging contrast agents in a tissue phantom, providing an up to ∼2.5-fold contrast enhancement over that of the benchmark contrast agent ICG. The testing protocol compares the photoacoustic signal output strength upon absorption of approximately the same light energy. Some relationships between photophysical parameters of the dyes and the resulting photoacoustic signal strength could be derived.