Silver Nanoparticle-Decorated Shape-Memory Polystyrene Sheets as Highly Sensitive Surface-Enhanced Raman Scattering Substrates with a Thermally Inducible Hot Spot Effect.

In this study, an active surface-enhanced Raman scattering (SERS) substrate with a thermally inducible hot spot effect for sensitive measurement of Raman-active molecules was successfully fabricated from silver nanoparticle (AgNP)-decorated shape-memory polystyrene (SMP) sheets. To prepare the SERS substrate, SMP sheets were first pretreated with n-octylamine for effective decoration with AgNPs. By varying the formulation and condition of the reduction reaction, AgNP-decorated SMP (Ag@SMP) substrates were successfully prepared with optimized particle gaps to produce inducible hot spot effects on thermal shrink. High-quality SERS spectra were easily obtained with enhancement factors higher than 108 by probing with aromatic thiols. Several Ag@SMP substrates produced under different reaction conditions were explored for the creation of inducible hot spot effects. The results indicated that AgNP spacing is crucial for strong hot spot effects. The suitability of Ag@SMP substrates for quantification was also evaluated according to the detection of adenine. Results confirmed that prepared Ag@SMP substrates were highly suitable for quantitative analysis because they yielded an estimated limit of detection as low as 120 pg/cm2, a linear range of up to 7 ng/cm2, and a regression coefficient (R2) of 0.9959. Ag@SMP substrates were highly reproducible; the average relative standard deviation for all measurements was less than 10%.

The impact of exogenous ω-6 and ω-3 polyunsaturated fatty acids on the induced production of pro- and anti-inflammatory prostaglandins and leukotrienes in Atlantic salmon head kidney cells using a full factorial design and LC-MS/MS.

The production of prostaglandins (PGE2, PGE3) and leukotrienes (LTB4, LTB5) in salmon head kidney cell cultures, exposed to different combinations of 20:4ω-6, 20:5ω-3 and 22:6ω-3 polyunsaturated fatty acids (PUFAs), was evaluated by means of a two level factorial design and LC-MS/MS. The method was selective for the pro- and anti-inflammatory analytes and their corresponding stable-isotope labelled internal standards. The regression models were linear over the concentration range 0.5-150 ng/ml with limits of detection of 0.25 ng/ml and quantification of 0.40 ng/ml for the analysed metabolites. The recovery ranged from 78 to 107% for prostaglandins and 73 to 115% for leukotrienes. The analysis of the samples exposed to different combinations of PUFAs revealed that the presence of single ω-3 PUFAs brought an enhancement of the metabolites from the lipooxygenase pathway, specially LTB4, and a reduction of the metabolites from the cyclooxygenase pathway (PGE2 and PGE3), while the two-term interactions generated the opposite effect (high concentration of prostaglandins and low concentrations of leukotrienes). To our knowledge, this is the first implementation of a fully crossed design for investigating the impact of ω-6 and ω-3 PUFAs on the production of eicosanoids not only through their individual but also through their combined effects on Atlantic salmon head kidney cells.

A co culture approach show that polyamine turnover is affected during inflammation in Atlantic salmon immune and liver cells and that arginine and LPS exerts opposite effects on p38MAPK signaling.

This study assess which pathways and molecular processes are affected by exposing salmon head kidney cells or liver cells to arginine supplementation above the established requirements for growth support. In addition to the conventional mono cultures of liver and head kidney cells, co cultures of the two cell types were included in the experimental set up. Responses due to elevated levels of arginine were measured during inflammatory (lipopolysaccharide/LPS) and non -inflammatory conditions. LPS up regulated the genes involved in polyamine turnover; ODC (ornithine decarboxylase), SSAT (spermidine/spermine-N1-acetyltransferase) and SAMdc (S-adenosyl methionine decarboxylase) in head kidney cells when co cultured with liver cells. Regardless of treatment, liver cells in co culture up regulated ODC and down regulated SSAT when compared to liver mono cultures. This suggests that polyamines have anti-inflammatory properties and that both salmon liver cells and immune cells seem to be involved in this process. The transcription of C/EBP ß/CCAAT, increased during inflammation in all cultures except for liver mono cultures. The observed up regulation of this gene may be linked to glucose transport due to the highly variable glucose concentrations found in the cell media. PPARα transcription was also increased in liver cells when receiving signals from head kidney cells. Gene transcription of Interleukin 1ß (IL-1ß), Interleukin-8 (IL-8), cyclooxygenase 2 (COX2) and CD83 were elevated during LPS treatment in all the head kidney cell cultures while arginine supplementation reduced IL-1ß and IL-8 transcription in liver cells co cultured with head kidney cells. This is probably connected to p38MAPK signaling as arginine seem to affect p38MAPK signaling contrary to the LPS induced p38MAPK signaling, suggesting anti-inflammatory effects of arginine/arginine metabolites. This paper shows that co culturing these two cell types reveals the connection between metabolism and inflammation, suggesting different pathways and candidate biomarkers to be further explored.

Development and validation of an extraction method for the determination of pro-inflammatory eicosanoids in human plasma using liquid chromatography-tandem mass spectrometry.

A simple method coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the extraction of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) from human plasma. The extraction protocol consisted of adding formic acid (10 µL) and acetonitrile (140 µL) to human plasma (50 µL) and further injection of the supernatant (25 µL) into the LC-MS/MS. The method was selective for PGE2 and LTB4 and the regression models, based on deuterated internal standards (30 ng mL(-1) PGE2-d4 and 40 ng mL(-1) LTB4-d4), were linear over the concentration range 1.0-50.0 ng mL(-1) with limits of detection (3 × σblank) and quantification (6 × σblank) of 0.5 ng mL(-1) and 1 ng mL(-1) for both eicosanoids. The recovery ranges were 95.1-104.7% for PGE2 and 86.4-103.2% for LTB4. The developed method was successfully implemented on plasma samples from patients before and after exposure to certain anti-inflammatory treatment.