Functional Somatic Symptoms and Emotion Regulation in Children and Adolescents.

Background: Functional Somatic Symptoms (FSS; i.e. symptoms without sufficient organic explanation) often begin in childhood and adolescence and are common to this developmental period. Emotion regulation and parental factors seem to play a relevant role in the development and maintenance of FSS. So far, little systematic research has been conducted in childhood and adolescence on the importance of specific emotion regulation strategies and their links with parental factors. Method: In two studies, children and adolescents (Study 1/Study 2: N = 46/68; 65%/60% female, Age M = 10.0/13.1) and their parents completed questionnaires on children's FSS and adaptive and maladaptive emotional regulation (in Study 2, additionally parental somatization and child/parental alexithymia). Results: In both studies, child-reported FSS were negatively associated with children's adaptive emotion regulation (r = -.34/-.31, p < .03; especially acceptance) and positively with children's maladaptive emotion regulation and alexithymia (r = .53/.46, p < .001). Moreover, children's maladaptive emotion regulation (ß = .34, p = .02) explained incremental variance in child-reported FSS beyond children's age/sex, parental somatization and emotion regulation. In contrast, parental somatization was the only significant predictor (ß = .44, p < .001) of parent-reported FSS in children/adolescents. Conclusion: Our results suggest that particularly rumination and alexithymia and parental somatization are important predictors of FSS in children/adolescents. Overall, the results showed a dependence on the person reporting children's FSS (i.e., method-variance). So, for future studies it is relevant to continue using the multi-informant approach.

Technological challenges in the preclinical development of an HIV nanovaccine candidate.

Despite a very active research in the field of nanomedicine, only a few nano-based drug delivery systems have reached the market. The "death valley" between research and commercialization has been partially attributed to the limited characterization and reproducibility of the nanoformulations. Our group has previously reported the potential of a peptide-based nanovaccine candidate for the prevention of SIV infection in macaques. This vaccine candidate is composed of chitosan/dextran sulfate nanoparticles containing twelve SIV peptide antigens. The aim of this work was to rigorously characterize one of these nanoformulations containing a specific peptide, following a quality-by-design approach. The evaluation of the different quality attributes was performed by several complementary techniques, such as dynamic light scattering, nanoparticle tracking analysis, and electron microscopy for particle size characterization. The inter-batch reproducibility was validated by three independent laboratories. Finally, the long-term stability and scalability of the manufacturing technique were assessed. Overall, these data, together with the in vivo efficacy results obtained in macaques, underline the promise this new vaccine holds with regard to its translation to clinical trials. Graphical abstract.

Advanced nanomedicine characterization by DLS and AF4-UV-MALS: Application to a HIV nanovaccine.

Nanoformulations are complex systems where physicochemical properties determine their therapeutic efficacy and safety. In the case of nanovaccines, particle size and shape play a crucial role on the immune response generated. Furthermore, the antigen's integrity is also a key aspect to control when producing a nanovaccine. The determination of all those physicochemical properties is still an analytical challenge and the lack of well-established methods hinders the access of new therapeutics to the market. In this work, robust methods for the characterization of a novel HIV nanoparticle-based vaccine produced in good manufacturing practice (GMPs)-like environment were developed. With slightly polydisperse particles (< 0.2) close to 180 nm of size, batch-mode Dynamic Light Scattering (DLS) was validated to be used as a quality control technique in the pilot production plant. In addition, a high size resolution method using Asymmetrical Flow Field Flow Fractionation (AF4) demonstrated its ability to determine not only size and size distribution but also shape modification across the size and accurate quantification of the free active ingredient. Results showed a monomodal distribution of particles from 60 to 700 nm, most of them (> 90%) with size lower than 250 nm, consistent with more traditional techniques, and revealed a slight change in the structure of the particles induced by the presence of the antigen. Finally, a batch to batch variability lower than 20% was obtained by both DLS and AF4 methods indicating that preparation method was highly reproducible.

Study of the presence of micro- and nanoparticles in drinks and foods by multiple analytical techniques.

A variety of food and drink samples (n = 21) were analyzed to evaluate the presence of (nano-) particles in their composition. After assessment of the sample pre-treatment step, a fast screening analysis was performed for drinks by Dynamic Light Scattering showing particles from 10 to 300 nm that could correspond to organic or metallic NPs. Metallic NPs were identified in foods by Single-Particle mode Inductively Coupled Plasma Mass Spectrometry and Asymmetrical Flow Field-Flow Fractionation coupled to Multiangle Laser Light Scattering and Inductively-Coupled Plasma Mass Spectrometry. The determination of Ti, Si and Ag concentration in the initial food suspensions, after filtration and centrifugal ultrafiltration enabled to estimate the ionic and nanoparticles content. Si-containing particles can be present in cappuccino powder as large aggregates and Si- and Al-containing particles in hot chocolate. Ti-containing NPs (80-200 nm) were found in chewing gum and Ag NPs in silver pearls (50-150 nm) used for decoration pastry.

Screening of TiO2 and Au nanoparticles in cosmetics and determination of elemental impurities by multiple techniques (DLS, SP-ICP-MS, ICP-MS and ICP-OES).

Cosmetics are part of the daily life of most of the people. Thus, a complete characterization of the products we applied in our skin is necessary. In this work, an analytical investigation of a wide variety of cosmetics from the point of view of total element content and metallic nanoparticles (NPs) has been performed. Firstly, we analyzed the total element content by ICP-MS and ICP-OES after acid digestion as an assessment of the presence of metal impurities. Prohibited elements in cosmetics, according to the European Commission regulation No 1223/2009, were not detected, and only elements mentioned in the label were found (e.g. Al, Fe, Ti and Si). Secondly, a screening of the presence of NPs has been performed by Dynamic Light Scattering (DLS) and Single Particle Inductively-Coupled Plasma Mass Spectrometry (SP-ICP-MS). Two sample preparation procedures were applied. The first protocol consisted in the preparation of suspensions in 0.1% w/v SDS and the second based on defatting with hexane followed by resuspension in water. DLS was employed as a routine method for a fast analysis of NPs, but this technique showed limitations due to the lack of specificity. SP-ICP-MS analyses were then performed, first as a screening technique to evaluate the presence of TiO2 and Au NPs in cosmetics suspensions prepared in SDS; and second, when a positive answer was obtained about the presence of NPs from the screening, SP-ICP-MS was used for particle size determination. Results showed that only TiO2 NPs were present in two sunscreens, one anti-wrinkle day cream, one lip balm protector labeled as 'nano' and in one brand of toothpaste not labeled as 'nano'. Sizes obtained for both sample preparations were compared and ranged from 30 to 120nm in most of the samples.

Identification in human urine and blood of a novel selenium metabolite, Se-methylselenoneine, a potential biomarker of metabolization in mammals of the naturally occurring selenoneine, by HPLC coupled to electrospray hybrid linear ion trap-orbital ion trap MS.

Speciation analysis of selenium in human urine allowed for the first time the identification of a novel selenium metabolite, Se-methylselenoneine. Despite a concentration at low ppb level, its characterization was achieved after sample purification by solid phase extraction (SPE) followed by the parallel coupling of the bidimensional RP/HILIC chromatography with ICP-MS and ESI-LTQ Orbitrap MS detection. To confirm its biological significance with regards to selenoneine, the recently discovered analog of ergothioneine, and to discard the possibility of sample preparation artifacts, a new method was developed to monitor its actual presence, as well as the occurrence of its sulfur and/or non-methylated analogs, in non-preconcentrated urine and blood samples of non-supplemented humans. It consisted in a HILIC ESI-MS(3) method in high resolution mode (resolution 30 000 at m/z 400) with large isolation width windows for precursor ions. These two particular settings allowed respectively to keep observing the specific mass defect of selenium- and sulfur-containing molecules and to maintain the characteristic selenium pattern in product ions created through MS(n) fragmentations. As a result, all four metabolites were detected in blood and three of them in urine. Moreover, different ratios "methylated/non-methylated" were observed between urine and blood samples, which seemed to indicate their active metabolization. The analytical tool developed here will be of a great importance to further study the occurrence and the potential metabolic role in mammalian organelles, cells and fluids of these very particular and promising redox metabolites.