Elemental imaging approach to comparative analysis of historical inks. Proof of concept based on non-invasive examinations of the Chopin manuscript as a case study.

This work presents an indirect method of investigating the elemental diversity of historical inks. The manuscript of Fryderyk Chopin's Impromptu in A flat major, Op. 29 was examined as an example of the proposed approach for testing documents containing different inks. Preliminary in situ X-ray fluorescence (XRF) measurements carried out it the museum storage room provided qualitative reference data for the object. Then, selected areas on the item were examined with indicator papers soaked in 4,7-diphenyl-1,10-phenanthroline (Bphen). The reaction with the ligand enabled the immediate colorimetric detection of Fe(II) in the form of magenta Fe(Bphen)3 complex. The overall condition of the manuscript with regard to the risk of ink corrosion was assessed in this way. More chemical information were obtained by the proposed elemental imaging-based approach to evaluate chemical heterogeneity of the used indicator paper samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The recorded data were visualised in the form of elemental distribution maps. The Fe enriched areas indicated Regions of Interest (ROIs) to approximate composition of the inks from the manuscript. All calculations were done solely for the data mathematically singled out from these areas. The varying proportions of AI, Mn, Co and Cu relative to Fe correlated with the ROIs of the composer's handwriting, editor's notes and stave lines, demonstrating the applicability of the proposed approach for comparative studies.

Assessment of safety and health-benefits of Citrus hystrix DC. peel essential oil, with regard to its bioactive constituents in an in vitro model of physiological and pathological skin conditions.

Citrus hystrix DC. peel essential oil (ChEO) has been reported to have many biological activities and is promoted for topical application. However, its effect on skin functioning has not yet been studied. This study aimed to evaluate its safety for normal skin cells as well as its potential activity against human melanoma. In addition, pro-inflammatory and anti-inflammatory activity was assessed, as well as inhibitory effects on important skin enzymes: tyrosinase and hyaluronidase. To better understand the complexity of the action of ChEO and the role of individual components, the study also included an evaluation of the activity of its main constituents: limonene, ß-pinene, and terpinen-4-ol as well as two mixtures of these compounds, specially designed for this purpose: M1 in equal proportions (1:1:1) and M2 in proportions mimicking those found in the ChEO (2.6:1.7:1). The results showed that the essential oil of the C. hystrix peel, as well as its major components, was not cytotoxic to normal human skin cells representing various skin layers, namely keratinocytes (HaCaT), melanocytes (HEM), and fibroblasts (HDF), even after prolonged exposure of 72 h. The pro-inflammatory effect of ChEO, tested by caspase-1 activation in HaCaT cells, was less pronounced compared to limonene, ß-pinene and terpinen-4-ol, and generally very low. On the other hand, its anti-inflammatory effect was noticeable and was half the potency of diclofenac sodium used as the reference drug. Although the anti-hyaluronidase activity of C. hystrix peel essential oil was lower compared to ß-pinene and terpinen-4-ol, ChEO revealed fairly high anti-tyrosinase activity, with an enzyme inhibition level of over 80% at a concentration of 150-220 µg/ml. Studies on the potential anti-melanoma effect were performed using the LDH assay on three human cell lines of varying degrees of malignancy, namely WM793, A375, and HTB140. ChEO was more active than the tested single compounds or their mixtures. WM793 cells were found to be most susceptible, while HTB140 and A375 cells were slightly more resistant (IC50 59, 88 and 70 µg/ml, respectively). Our data indicate that ChEO is safe for the skin and has a perspective as an anti-melanoma agent.

Drug interaction at hERG channel: In vitro assessment of the electrophysiological consequences of drug combinations and comparison against theoretical models.

Drugs carry a proarrhythmic risk, which gets even greater when they are used in combination. In vitro assessment of the proarrhythmic potential of drugs is limited to one compound and thus neglects the potential of drug-drug interactions, including those involving active metabolites. Here we present the results of an in vitro study of potential drug-drug interactions at the level of the hERG channel for the combination of up to three compounds: loratadine, desloratadine and ketoconazole. Experiments were performed at room temperature on an automated patch-clamp device CytoPatch 2, with the use of heterogeneously, stably transfected HEK cells. Single drugs, pairs and triplets were used. The results provided as the inhibition of the IKr current for pairs were compared against the calculated theoretical interaction. Models applied to calculate the combined effect of inhibitory actions of simultaneously given drugs include: (1) simple additive model with a maximal inhibition limit of 1 (all channels blocked in 100%); (2) Bliss independence; and (3) Loewe additivity. The observed IC50 values for loratadine, desloratadine and ketoconazole were 5.15, 1.95 and 0.74 µm respectively. For the combination of drugs tested in pairs, the effect was concentration dependent. In lower concentrations, the synergistic effect was observed, while for the highest tested concentrations it was subadditive. To triple the effect, it was subadditive regardless of concentrations. The square root of sum of squares of differences between the observed and predicted total inhibition was calculated to assess the theoretical interaction models. For most of the drugs, the allotopic model offered the best fit.