Morphological and Genomic Differences in the Italian Populations of Onopordum tauricum Willd.-A New Source of Vegetable Rennet

Onopordum tauricum Willd., a species distributed in Eastern Europe, has been the subject of various research endeavors aimed at assessing its suitability for extracting vegetable rennet for use in the production of local cheeses as a substitute for animal-derived rennet. In Italy, the species has an extremely fragmented and localized distribution in six locations scattered across the central-northern Apennines and some areas of southern Italy. In this study, both the morphology and genetic diversity of the six known Italian populations were investigated to detect putative ecotypes. To this end, 33 morphological traits were considered for morphometric measurements, while genetic analysis was conducted on the entire genome using the ddRAD-Seq method. Both analyses revealed significant differences among the Apennine populations (SOL, COL, and VIS) and those from southern Italy (ROT, PES, and LEC). Specifically, the southern Italian populations appear to deviate significantly in some characteristics from the typical form of the species. Therefore, its attribution to O. tauricum is currently uncertain, and further genetic and morphological analyses are underway to ascertain its systematic placement within the genus Onopordum.

Self-oriented anisotropic structure of G-hydrogels as a delicate balance between attractive and repulsive forces

Guanine (G) hydrogels are very attractive materials made by the supramolecular organization of G-derivatives in water. In this paper, hydrogels composed of guanosine 5'-monophosphate (GMP) and guanosine (Gua), that make long, flexible and knotted G-quadruplexes, were investigated by small- and wide-angle X-ray scattering (SAXS and WAXS) to comprehend the origin of their unique orientational properties. The SAXS intensity, analysed at a fixed scattering vector modulus Q as a function of polar angle, allowed us to derive the Maier-Saupe orientation parameter m. The strong dependence of m on hydrogel composition and temperature demonstrated that the preferred orientation is controlled by the quadruplex surface charge and flexibility. Indeed, a possible correlation between the orientation parameter m and the quadruplex-to-quadruplex lateral interactions was explored. Results confirmed that the balance between attractive and repulsive interactions plays a main role in the orientational anisotropy: quadruplex clusters lose their orientational properties when attractive interactions decrease. The key role of the number of negative charges per unit length of the G-quadruplex filaments was confirmed by Atomic Force Microscopy (AFM) observations. Indeed, directionality histograms showed that in the presence of a large amount of Gua, G-quadruplexes follow preferential orientations other than those related to the strong interactions with the K+ pattern on the mica surface. The fact that lateral quadruplex-to-quadruplex interactions, even in the presence of external (opposing) forces, can tune the hydrogel alignment in a given preferred direction provides novel possibilities for scaffold/3D printing applications.

Transposable Elements: Epigenetic Silencing Mechanisms or Modulating Tools for Vertebrate Adaptations? Two Sides of the Same Coin

Transposable elements constitute one of the main components of eukaryotic genomes. In vertebrates, they differ in content, typology, and family diversity and played a crucial role in the evolution of this taxon. However, due to their transposition ability, TEs can be responsible for genome instability, and thus silencing mechanisms were evolved to allow the coexistence between TEs and eukaryotic host-coding genes. Several papers are highlighting in TEs the presence of regulatory elements involved in regulating nearby genes in a tissue-specific fashion. This suggests that TEs are not sequences merely to silence; rather, they can be domesticated for the regulation of host-coding gene expression, permitting species adaptation and resilience as well as ensuring human health. This review presents the main silencing mechanisms acting in vertebrates and the importance of exploiting these mechanisms for TE control to rewire gene expression networks, challenging the general view of TEs as threatening elements.

LTR Retroelements and Bird Adaptation to Arid Environments

TEs are known to be among the main drivers in genome evolution, leading to the generation of evolutionary advantages that favor the success of organisms. The aim of this work was to investigate the TE landscape in bird genomes to look for a possible relationship between the amount of specific TE types and environmental changes that characterized the Oligocene era in Australia. Therefore, the mobilome of 29 bird species, belonging to a total of 11 orders, was analyzed. Our results confirmed that LINE retroelements are not predominant in all species of this evolutionary lineage and highlighted an LTR retroelement dominance in species with an Australian-related evolutionary history. The bird LTR retroelement expansion might have happened in response to the Earth’s dramatic climate changes that occurred about 30 Mya, followed by a progressive aridification across most of Australian landmasses. Therefore, in birds, LTR retroelement burst might have represented an evolutionary advantage in the adaptation to arid/drought environments.

Transposable Element Tissue-Specific Response to Temperature Stress in the Stenothermal Fish Puntius tetrazona

Ray-finned fish represent a very interesting group of vertebrates comprising a variety of organisms living in different aquatic environments worldwide. In the case of stenothermal fish, thermal fluctuations are poorly tolerated, thus ambient temperature represents a critical factor. In this paper, we considered the tiger barb Puntius tetrazona, a freshwater fish belonging to the family Cyprinidae, living at 21-28 °C. We analyzed the available RNA-Seq data obtained from specimens exposed at 27 °C and 13 °C to investigate the transcriptional activity of transposable elements (TEs) and genes encoding for proteins involved in their silencing in the brain, gill, and liver. TEs are one of the tools generating genetic variability that underlies biological evolution, useful for organisms to adapt to environmental changes. Our findings highlighted a different response of TEs in the three analyzed tissues. While in the brain and gill, no variation in TE transcriptional activity was observed, a remarkable increase at 13 °C was recorded in the liver. Moreover, the transcriptional analysis of genes encoding proteins involved in TE silencing such as heterochromatin formation, the NuRD complex, and the RISC complex (e.g., AGO and GW182 proteins) highlighted their activity in the hepatic tissue. Overall, our findings suggested that this tissue is a target organ for this kind of stress, since TE activation might regulate the expression of stress-induced genes, leading to a better response of the organism to temperature changes. Therefore, this view corroborates once again the idea of a potential role of TEs in organism rapid adaptation, hence representing a promising molecular tool for species resilience.

The Mantle Transcriptome of Chamelea gallina (Mollusca: Bivalvia) and Shell Biomineralization

Simple Summary

Chamelea gallina is a bivalve mollusc that represents one of the most important fishery resources in the Mediterranean basin. In this species, the thickness and sturdiness of the shell valves are two important characteristics as they are decisive for protection against predators and survival of specimens rejected in the sea because caught under commercial size. The aim of this work is to investigate the ability of this species to modulate the expression of genes encoding proteins involved in shell biomineralization process in response to abiotic and biotic factors. Our findings, obtained through a multidisciplinary approach, highlighted a different shell mineralization behaviour in C. gallina clams collected in sampling sites characterized by different salinity and food availability. Moreover, this study provided the first comprehensive transcriptome from mantle, the tissue responsible for shell formation. Therefore, these results contribute to increase knowledge on this process and might help in adopting ad hoc management plans for this fishery resource.

Abstract

The striped venus Chamelea gallina is a bivalve mollusc that represents one of the most important fishery resources of the Adriatic Sea. In this work, we investigated for the first time the ability of this species to modulate the expression of genes encoding proteins involved in biomineralization process in response to biotic and abiotic factors. We provided the first comprehensive transcriptome from the mantle tissue of clams collected in two sampling sites located along the Italian Adriatic coast and characterized by different environmental features. Moreover, the assessment of environmental parameters, scanning electron microscopy (SEM), and X-ray diffraction (XRD) measurements on valves were conducted to better contextualize RNA sequencing (RNA-Seq) data. Functional annotation of differentially expressed genes (DEGs) and SEM observations highlighted a different shell mineralization behaviour in C. gallina clams collected from two selected sites characterized by diverse environmental parameters.

The ALA5/ALA6/ALA7 repeat polymorphisms of the glutathione peroxidase-1 (GPx1) gene and autism spectrum disorder

Autism is a severe neurodevelopmental disorder leading to deficits in social interaction, communication, and several activities. An increasing number of evidence suggests a role of oxidative stress in the etiology of autism spectrum disorder (ASD). Indeed, impaired antioxidant mechanisms may lead to the inadequate removal of H₂O₂ with a consequent increase in highly active hydroxyl radicals and other reactive oxygen species causing cellular damages. The GPx1 is one of the most important enzymes counteracting oxidative stress. In this work, we investigated a possible correlation between the GCG repeat polymorphism present in the first exon of GPx1 gene encoding a tract of five to seven alanine residues (ALA5, ALA6, and ALA7) and ASD. Our findings highlighted a high frequency of ALA5 allele in ASD subjects. Moreover, proteins corresponding to the three GPx1 variants were produced in vitro, and the evaluation of their activity showed a lower values for GPx1 having ALA5 polymorphism. The comparison of the secondary and tertiary structure predictions revealed an alpha‐helix in correspondence of alanine stretch only in the case of GPx1‐ALA7 variant. Finally, to better investigate protein structure, steady‐state fluorescence measurements of GPx1 intrinsic tryptophan were carried out and the three tested proteins exhibited a different stability under denaturing conditions. This work demonstrates the importance in adopting a multidisciplinary strategy to comprehend the role of GPx1 in ASD.

Results here obtained suggest a possible role of ALA5 GPx1 variant in ASD. However, given the multifactorial nature of autism, this evidence might be a piece of a more complex puzzle being the GPx1 enzyme part of a complex pathway in which several proteins are involved.

The vitellogenin genes in Cynops orientalis: New insights on the evolution of the vtg gene family in amphibians

The vitellogenins (Vtgs) are glycolipophosphoproteins that play a key role in constituting nutritional reserves for embryo development in nonmammalian vertebrates. However, additional functional roles have been evidenced. These vtg genes are present in multiple copies, different in number and sequences in various vertebrate lineages. The comprehension of the vtg gene family evolutionary history remains a matter of intense interrogation for this field of research. In tetrapods, information about vtg genes are limited to few taxa. Up to date concerning amphibians, detailed studies have been conducted only in Anura. Therefore, in this study, to further increase knowledge about vtg genes in Amphibia class, the urodele Cynops orientalis (Amphibia: Caudata) was analyzed and four complete vtg sequences were obtained. Moreover, genomic data available for the caecilians Microcaecilia unicolor and Rhinatrema bivittatum (Amphibia: Gymnophiona) were also included. In these amphibians, our findings evidenced the presence of a vtgI sequence ortholog to that of tetrapods, absent in Anura. Moreover, microsyntenic, phylogenetic, and gene conversion analyses allowed postulating two hypotheses to explain the complex evolutionary history of this gene family.

Investigation of the activity of transposable elements and genes involved in their silencing in the newt Cynops orientalis, a species with a giant genome

Caudata is an order of amphibians with great variation in genome size, which can reach enormous dimensions in salamanders. In this work, we analysed the activity of transposable elements (TEs) in the transcriptomes obtained from female and male gonads of the Chinese fire-bellied newt, Cynops orientalis, a species with a genome about 12-fold larger than the human genome. We also compared these data with genomes of two basal sarcopterygians, coelacanth and lungfish. In the newt our findings highlighted a major impact of non-LTR retroelements and a greater total TE activity compared to the lungfish Protopterus annectens, an organism also characterized by a giant genome. This difference in TE activity might be due to the presence of young copies in newt in agreement also with the increase in the genome size, an event that occurred independently and later than lungfish. Moreover, the activity of 33 target genes encoding proteins involved in the TE host silencing mechanisms, such as Ago/Piwi and NuRD complex, was evaluated and compared between the three species analysed. These data revealed high transcriptional levels of the target genes in both newt and lungfish and confirmed the activity of NuRD complex genes in adults. Finally, phylogenetic analyses performed on PRDM9 and TRIM28 allowed increasing knowledge about the evolution of these two key genes of the NuRD complex silencing mechanism in vertebrates. Our results confirmed that the gigantism of the newt genomes may be attributed to the activity and accumulation of TEs.

Omics approaches for conservation biology research on the bivalve Chamelea gallina

The striped venus (Chamelea gallina) is an important economic resource in the Mediterranean Basin; this species has exhibited a strong quantitative decline in the Adriatic Sea. The aim of this work was to provide a comprehensive view of the biological status of C. gallina to elucidate the bioecological characteristics and genetic diversity of wild populations. To the best of our knowledge, this investigation is the first to perform a multidisciplinary study on C. gallina based on two omics approaches integrated with histological, ecotoxicological, and chemical analyses and with the assessment of environmental parameters. The results obtained through RNA sequencing indicated that the striped venus has a notable ability to adapt to different environmental conditions. Moreover, the stock reduction exhibited by this species in the last 2 decades seems not to have negatively affected its genetic diversity. Indeed, the high level of genetic diversity that emerged from our ddRAD dataset analyses is ascribable to the high larval dispersal rate, which might have played a “compensatory role” on local fluctuations, conferring to this species a good adaptive potential to face the environmental perturbations. These findings may facilitate the efforts of conservation biologists to adopt ad hoc management plans for this fishery resource.

Mobile Elements in Ray-Finned Fish Genomes

Ray-finned fishes (Actinopterygii) are a very diverse group of vertebrates, encompassing species adapted to live in freshwater and marine environments, from the deep sea to high mountain streams. Genome sequencing offers a genetic resource for investigating the molecular bases of this phenotypic diversity and these adaptations to various habitats. The wide range of genome sizes observed in fishes is due to the role of transposable elements (TEs), which are powerful drivers of species diversity. Analyses performed to date provide evidence that class II DNA transposons are the most abundant component in most fish genomes and that compared to other vertebrate genomes, many TE superfamilies are present in actinopterygians. Moreover, specific TEs have been reported in ray-finned fishes as a possible result of an intricate relationship between TE evolution and the environment. The data summarized here underline the biological interest in Actinopterygii as a model group to investigate the mechanisms responsible for the high biodiversity observed in this taxon.

Gelling without Structuring: A SAXS Study of the Interactions among DNA Nanostars

We evaluate, by means of synchrotron small-angle X-ray scattering, the shape and mutual interactions of DNA tetravalent nanostars as a function of temperature in both the gas-like state and across the gel transition. To this end, we calculate the form factor from coarse-grained molecular dynamics simulations with a novel method that includes hydration effects; we approximate the radial interaction of DNA nanostars as a hard-sphere potential complemented by a repulsive and an attractive Yukawa term; and we predict the structure factors by exploiting the perturbative random phase approximation of the Percus-Yevick equation. Our approach enables us to fit all the data by selecting the particle radius and the width and amplitude of the attractive potential as free parameters. We determine the evolution of the structure factor across gelation and detect subtle changes of the effective interparticle interactions, that we associate to the temperature and concentration dependence of the particle size. Despite the approximations, the approach here adopted offers new detailed insights into the structure and interparticle interactions of this fascinating system.

Playing supramolecular dominoes with light: building and breaking a photoreversible G-quadruplex made from guanosine, boric acid and an azobenzene

Addition of azobenzene-derivative 1 in its E configuration to an aqueous solution containing various guanosine borate esters induces a helical G-quartet based self-organization, stabilized by intercalation of the dye. The process is driven, in a domino fashion, by the initial host-guest interaction between the dye and a specific guanosine borate diester, whose structure can be thus assigned. This inclusion complex templates the formation of G-quartets. The quartets, in turn, pile up to form a supramolecular G-quadruplex structure, in which other G species present in solution are progressively included. The G-quadruplex can be reversibly broken and reformed by photoisomerization of the dye. This hierarchical and photosensitive self-assembly is unprecedented for simple guanosine derivatives.

X-Ray Characterization of Pharmaceutical and Cosmetic Lipidic Nanoparticles for Cutaneous Application

Starting from the second half of the 1900s, the advent of nanotechnology in medicine has provoked a profound revolution in this area; at present, nanomedicine delivered a remarkably large set of research and clinically useful tools as diagnostic devices, contrast agents, analytical tools, physical therapy applications, and drugdelivery vehicles. Concerning nanoformulations for drug delivery, they are constituted by nanoparticles with dimensions lower than 1 μm, usually characterized by improved pharmacokinetics, taking advantage of specific targeting, and reduced side effects. The contributors to the present chapter are reviewing a range of papers related to the structural characterization of nanoformulations by X-ray diffraction techniques. The whole of the considered papers underlines the essential role that biophysical techniques have acquired as an essential prerequisite to understanding stability, bioavailability, and lipid, biopolymer, and drug organization in nanoformulations.

An intriguing relationship between teleost Rex3 retroelement and environmental temperature

The movement and accumulation of transposable elements (TEs) exert a great influence on the host genome, e.g. determining architecture and genome size, providing a substrate for homologous recombination and DNA rearrangements. TEs are also known to be responsive and susceptible to environmental changes. However, the correlation between environmental conditions and the sequence evolution of TEs is still an unexplored field of research. Among vertebrates, teleosts represent a successful group of animals adapted to a wide range of different environments and their genome is constituted by a rich repertoire of TEs. The Rex3 retroelement is a lineage-specific non-LTR retrotransposon and thus represents a valid candidate for performing comparative sequence analyses between species adapted to diverse temperature conditions. Partial reverse transcriptase sequences of the Rex3 retroelement belonging to 39 species of teleosts were investigated through phylogenetic analysis to evaluate whether the species' adaptation to different environments led to the evolution of different Rex3 temperature-related variants. Our findings highlight an intriguing behaviour of the analysed sequences, showing clustering of Rex3 sequences isolated from species living in cold waters (Arctic and Antarctic regions and cold waters of temperate regions) compared with those isolated from species living in warm waters. This is the first evidence to our knowledge of a correlation between environmental temperature and Rex3 retroelement evolution.

Lipid nanostructures for antioxidant delivery: a comparative preformulation study

This investigation is a study of new lipid nanoparticles for cutaneous antioxidant delivery. Several molecules, such as α-tocopherol and retinoic acid, have been shown to improve skin condition and even counteract the effects of exogenous stress factors such as smoking on skin aging. This work describes the design and development of lipid nanoparticles containing antioxidant agents (α-tocopherol or retinoic acid) to protect human skin against pollutants. Namely, solid lipid nanoparticles and nanostructured lipid carriers were prepared using different lipids (tristearin, compritol, precirol or suppocire) in the presence or absence of caprylic/capric triglycerides. The formulations were characterized by particle size analysis, cryogenic transmission electron microscopy, small-angle X-ray diffraction, encapsulation efficiency, preliminary stability, in vitro cytotoxicity and protection against cigarette smoke. Nanostructured lipid carriers were found to reduce agglomerate formation and provided better dimensional stability, as compared to solid lipid nanoparticles, suggesting their suitability for antioxidant loading. Based on the preformulation study, tristearin-based nanostructured lipid carriers loaded with α-tocopherol were selected for ex vivo studies since they displayed superior physico-chemical properties as compared to the other nanostructured lipid carriers compositions. Human skin explants were treated with α-tocopherol-loaded nanostructured lipid carriers and then exposed to cigarette smoke, and the protein levels of the stress-induced enzyme heme oxygenase were analyzed in skin homogenates. Interestingly, it was found that pretreatment with the nanoformulation resulted in significantly reduced heme oxygenase upregulation as compared to control samples, suggesting a protective effect provided by the nanoparticles.

The p53 gene family in vertebrates: Evolutionary considerations

The origin of the p53 gene family predates multicellular life since TP53 members of this gene family have been found in unicellular eukaryotes. In invertebrates one or two genes attributable to a TP53-like or TP63/73-like gene are present. The radiation into three genes, TP53, TP63, and TP73, has been reported as a vertebrate invention. TP53 is considered the "guardian of the genome" given its role in protecting cells against the DNA damage and cellular stressors. TP63 and TP73 play a role in epithelial development and neurogenesis, respectively. The evolution of the p53 gene family has been the subject of considerable analyses even if several questions remain still open. In this study we addressed the evolutionary history of the p53 gene family in vertebrates performing an extended microsyntenic investigation coupled with a phylogenetic analysis, together with protein domain organization and structure assessment. On the basis of our results we discussed a possible evolutionary scenario according to which a TP53/63/73 ancestor form gave rise to the current TP53 and a TP63/73 form, which in turn independently duplicated into two genes in agnathe and gnathostome lineages.

Quadruplex knots as network nodes: nano-partitioning of guanosine derivates in supramolecular hydrogels

Aqueous solutions of guanosine-5'-monophosphates (GMP) - known to form G-quadruplexes and liquid crystal phases - can be induced to turn into high water content gels by the addition of guanosine (Gua). By a combination of Light Scattering (LS) and AFM we show that Gua/GMP hydrogels are microscopically heterogeneous, formed by Gua-rich disordered microcoils of intertwined filaments ("knots") connected by GMP-rich long linear threads. The different thermal stability of knots and threads controls the gel transition.

Rex Retroelements and Teleost Genomes: An Overview

Repetitive DNA is an intriguing portion of the genome still not completely discovered and shows a high variability in terms of sequence, genomic organization, and evolutionary mode. On the basis of the genomic organization, it includes satellite DNAs, which are organized as long arrays of head-to-tail linked repeats, and transposable elements, which are dispersed throughout the genome. These repeated elements represent a considerable fraction of vertebrate genomes contributing significantly in species evolution. In this review, we focus our attention on Rex1, Rex3 and Rex6, three elements specific of teleost genomes. We report an overview of data available on these retroelements highlighting their significative impact in chromatin and heterochromatin organization, in the differentiation of sex chromosomes, in the formation of supernumerary chromosomes, and in karyotype evolution in teleosts.

Production and Characterization of Nanoparticle Based Hyaluronate Gel Containing Retinyl Palmitate for Wound Healing

BACKGROUND

Wound healing is a biological process that can get in a state of pathologic inflammation, requiring the use of specific medications able to promote proper tissue repair.

OBJECTIVE

The study describes the production and characterization of nanoparticle based gel for wound healing treatment designed to deliver hyaluronic acid and retinyl palmitate onto the skin.

METHODS

Tristearin solid lipid nanoparticles and nanostructured lipid carriers based on a tristearin and caprylic/capric triglyceride mixture were produced and characterized. Gel spreadability and viscosity were investigated. Drug diffusion and "in vitro" wound healing were assessed by Franz cell and scratch wound assay in keratinocytes.

RESULTS

Cryogenic transmission electron microscopy evidenced flat discoid nanoparticles. Photon correlation spectroscopy analysis indicated homogeneous dimensional distribution and mean diameter 132±46 nm. X-ray evidenced a lamellar inner structure of lipid nanoparticles. Nanostructured lipid carriers, being based on a heterogeneous solid/ liquid lipid mixture, could better solubilize retinyl palmitate and control its stability. The hyaluronic acid directly added into nanoparticles' dispersion enabled to obtain a shear-thinning gel suitable for cutaneous administration. Retynil palmitate diffusion was slower from the nanoparticulate gel with respect to the plain nanoparticle dispersion. The "wound healing" effect of nanoparticulate gel containing retinyl palmitate and hyaluronic acid, analyzed in HaCaT cells, showed significant differences in wounded areas between treated and control cells during the first 24 h postwounding suggesting a synergic effect of retinyl palmitate and hyaluronic acid in "in vitro" wound healing.

CONCLUSIONS

This study suggests that a nanoparticle based hyaluronate gel containing retinyl palmitate can be efficiently used for wound healing.

New Perspectives on the Evolutionary History of Vitellogenin Gene Family in Vertebrates

Vitellogenin (Vtg) is a glycolipophosphoprotein produced by oviparous and ovoviviparous species and is the precursor protein of the yolk, an essential nutrient reserve for embryonic development and early larval stages. Vtg is encoded by a family of paralog genes whose number varies in the different vertebrate lineages. Its evolution has been the subject of considerable analyses but it remains still unclear. In this work, microsyntenic and phylogenetic analyses were performed in order to increase our knowledge on the evolutionary history of this gene family in vertebrates. Our results support the hypothesis that the vitellogenin gene family is expanded from two genes both present at the beginning of vertebrate radiation through multiple independent duplication events occurred in the diverse lineages.

On the structural stability of guanosine-based supramolecular hydrogels

Supramolecular hydrogels formed from the self-assembly of low molecular weight derivatives are very attractive systems, because of their potential applications in nano- and bio-technology. In this paper, the stable and transparent hydrogels observed in binary mixtures of guanosine derivatives (G), namely guanosine 5'-monophosphate (GMP) and guanosine (Gua), dissolved in water (at volume fractions larger than 0.95), were investigated by microscopy techniques and Small Angle X-ray Scattering (SAXS). The results confirm the presence of G-quadruplexes, chiral cylindrical rods obtained by the regular stacking of self-assembled planar cyclic guanosine quartets. However, the addition of Gua determines the formation of very stable hydrogels able to trap large amounts of water (up to a volume fraction of 0.99) and characterised by an unusual anisotropic order. A modified lateral helix-to-helix interaction pattern, tuned by Gua, is suggested to be responsible for the supramolecular gelation and the stability of the hydrogels during swelling.

Classification of EEG Mental Patterns by Using Two Scalp Electrodes and Mahalanobis Distance-Based Classifiers

Objectives: In this paper, we explored the use of quadratic classifiers based on Mahalanobis distance to detect mental EEG patterns from a reduced set of scalp recording electrodes.

Methods: Electrodes are placed in scalp centro-parietal zones (C3, P3, C4 and P4 positions of the international 10-20 system). A Mahalanobis distance classifier based on the use of full covariance matrix was used.

Results: The quadratic classifier was able to detect EEG activity related to imagination of movement with an affordable accuracy (97% correct classification, on average) by using only C3 and C4 electrodes.

Conclusions: Such a result is interesting for the use of Mahalanobis-based classifiers in the brain computer interface area.

EEG Deblurring Techniques in a Clinical Context

Objectives: EEG scalp potential distributions recorded in humans are affected by low spatial resolution and by the dependence on the electrical reference used. High resolution EEG technologies are available to drastically increase the spatial resolution of the raw EEG. Such technologies include the computation of surface Laplacian (SL) of the recorded potentials, as well as the use of realistic head models to estimate the cortical sources via linear inverse procedure (low resolution brain electromagnetic tomography, LORETA). However, these deblurring procedures are generally used in conjunction with EEG recordings with 64-128 scalp electrodes and with realistic head models obtained via sequential magnetic resonance images (MRIs) of the subjects. Such recording setup it is not often available in the clinical context, due to both the unavailability of these technologies and the scarce compliance of the patients with them. In this study we addressed the use of SL and LORETA deblurring techniques to analyze data from a standard 10-20 system (19 electrodes) in a group of Alzheimer disease (AD) patients.

Methods: EEG data related to unilateral finger movements were gathered from 10 patients affected by AD. SL and LORETA techniques were applied for source estimation of EEG data. The use of MRIs for the construction of head models was avoided by using the quasi-realistic head model of the Brain Imaging Neurology Institute of Montreal.

Results: A similar cortical activity estimated by the SL and LORETA techniques was observed during an identical time period of the acquired EEG data in the examined population.

Conclusions: The results of the present study suggest that both SL and LORETA approaches can be usefully applied in the clinical context, by using quasi-realistic head modeling and a standard 10-20 system as electrode montage (19 electrodes). These results represent a reciprocal cross-validation of the two mathematically independent techniques in a clinical environment.

Integration of High Resolution EEG and Functional Magnetic Resonance in the Study of Human Movement-Related Potentials

Cortical sources of human movement-related potentials (i.e. unilateral finger extension) were modeled using functional magnetic resonance imaging (fMR) data as a constraint of a linear inverse source estimation from highly sampled (128 channels) EEG data. Remarkably, this estimation was performed within realistic subject’s MR-constructed head models by boundary element techniques. An appropriate figure of merit served to set the optimal amount of fMR constraints. With respect to standard linear inverse source estimates, fMR-constrained ones presented increased spatial detail and provided a more reliable timing of activation in bilateral sensorimotor cortical regions of interest.

Cortical Source Estimate of Combined High Resolution EEG and fMRI Data Related to Voluntary Movements

Objectives: In this paper, we employed advanced methods for the modeling of human cortical activity related to voluntary right one-digit movements from combined high-resolution electroencephalography (EEG) and functional magnetic resonance imaging (fMRI).

Methods: Multimodal integration between EEG and fMRI data was performed by using realistic head models, a large number of scalp electrodes (128) and the estimation of current density strengths by linear inverse estimation.

Results: Increasing of spatial details of the estimated cortical density distributions has been detected by using the proposed integration method with respect to the estimation using EEG data alone.

Conclusion: The proposed method of multimodal EEG-fMRI data is useful to increase spatial resolution of movement-related potentials and can also be applied to other kinds of event-related potentials.

Independent Component Analysis Compared to Laplacian Filtering as ”Deblurring” Techniques for Event Related Desynchronization/ Synchronization

Objectives: The aim of the work was to compare two different approaches – one model-dependent, the other data-dependent – for “deblurring” EEG data, in order to improve the estimation of Event-Related Desynchronization/Synchronization.

Methods: Realistic Surface Laplacian filtering (SL) and Infomax Independent Component Analysis (ICA) were applied on multivariate scalp EEG signals (SL: 128 electrodes with MRI-based realistic modeling; ICA: a subset of 19 electrodes, no MRI) prior to beta Event Related Synchronization (ERS) estimation after finger movement in 8 normal subjects. ERS estimation was performed using standard band-pass filtering. ERS peak amplitudes and latencies in the most responsive channel were calculated and the effect of the two methods above was evaluated by one-way analysis of variance (ANOVA) and Sheffe’s test.

Results: Both methods and their combination significantly improved ERS estimation (greater ERS peak amplitude, p <0.05). The results obtained after ICA on 19 electrodes were not significantly different than the ones obtained with Realistic SL using 128 electrodes and MRI for scalp modeling (p >0.89).

Conclusions: The “low cost” of ICA (19 electrodes, no MRI) imposes such method as a valid alternative to SL filtering. The employ of ICA after SL filtering suggests that the “ideal EEG deblurring method” would unify the two approaches, depending on both the scalp model and the data.

Monoolein aqueous dispersions as a delivery system for quercetin

This study describes the preparation, characterization and in vitro release of monoolein aqueous dispersions (MAD) encapsulating quercetin (QT). As emulsifier, sodium cholate was employed at two different concentrations, namely 0.15% and 0.25% with respect to the total weight of the formulation. Cryogenic Transmission electron microscopy and X-ray analysis indicated that MAD015 are a mixture of vesicles and cubic structures, whilst MAD025 are mainly characterized by unilamellar vesicular structures. Photon correlation spectroscopy (PCS) and Sedimentation Field Flow Fractionation (SdFFF) showed a MAD size higher than 300 nm that over 100 days from analysis reduces up to 200 nm. In vitro Franz cell experiments showed that the two systems had a similar behaviour in the release of QT. Experiments on antioxidant activity of MAD containing QT demonstrated that their activity parallel with the content of encapsulated QT within the MAD formulations produced. Taken together these results allow us to conclude that MAD can be potentially proposed for the delivery of QT.

Data on scaling up and in vivo human study of progesterone lipid nanoparticles

Progesterone containing nanoparticles constituted of tristearin or tristearin in association with caprylic-capric triglyceride were produced in a lab scale by ultrasound homogenization and in a pilot scale by high pressure homogenization. A study was conducted to select the pressure to be used in order to obtain homogenously sized nanoparticles. The Dialysis method was performed to mimic subcutaneous administration of lipid nanoparticles. Mathematical analyses of the results were conducted to understand and compare the drug release mechanisms. A human in vivo study, based on tape stripping, was conducted to investigate the performance of nanoparticles as progesterone skin delivery systems. Tape stripped stratum corneum was analyzed by light microscopy.

Progesterone lipid nanoparticles: Scaling up and in vivo human study

This investigation describes a scaling up study aimed at producing progesterone containing nanoparticles in a pilot scale. Particularly hot homogenization techniques based on ultrasound homogenization or high pressure homogenization have been employed to produce lipid nanoparticles constituted of tristearin or tristearin in association with caprylic-capric triglyceride. It was found that the high pressure homogenization method enabled to obtain nanoparticles without agglomerates and smaller mean diameters with respect to ultrasound homogenization method. X-ray characterization suggested a lamellar structural organization of both type of nanoparticles. Progesterone encapsulation efficiency was almost 100% in the case of high pressure homogenization method. Shelf life study indicated a double fold stability of progesterone when encapsulated in nanoparticles produced by the high pressure homogenization method. Dialysis and Franz cell methods were performed to mimic subcutaneous and skin administration. Nanoparticles constituted of tristearin in mixture with caprylic/capric triglyceride display a slower release of progesterone with respect to nanoparticles constituted of pure tristearin. Franz cell evidenced a higher progesterone skin uptake in the case of pure tristearin nanoparticles. A human in vivo study, based on tape stripping, was conducted to investigate the performance of nanoparticles as progesterone skin delivery systems. Tape stripping results indicated a decrease of progesterone concentration in stratum corneum within six hours, suggesting an interaction between nanoparticle material and skin lipids.

Solid lipid nanoparticles for the delivery of 1,3,5-triaza-7-phosphaadamantane (PTA) platinum (II) carboxylates

The use of solid lipid nanoparticles (SLN) is a promising route for the delivery of platinum complexes aimed to anticancer activity. This paper describes the production and characterization of SLN suitable for the loading of Pt complexes containing the biocompatible phosphine 1,3,5-triaza-7-phosphaadamantane (PTA) as neutral ligand. After a screening of several lipidic phases, stearic acid-based SLN were identified as the most appropriate for the purpose. They were produced by emulsion-dilution method and then characterized in terms of dimension, polydispersity, time stability, pH balance and morphological aspect. Stearic acid SLN are designed as a system able to coordinate to platinum, acting as anionic carboxylic ligands, replacing the base carbonate of the Pt synthon [PtCO₃(DMSO)₂], where also DMSO can subsequently be substituted by phosphinic ligands, namely PTA. SLN functionalised with Pt-PTA were produced and characterized by this synthetic route. The toxicity of plain SLN and the antiproliferative effect of SLN functionalised with Pt-PTA were evaluated on two human cancer cell lines K562 and A2780. The results indicate that SLN can be exploited as a delivery system for Pt complexes with potential anticancer activity.

Nanostructured lipid dispersions for topical administration of crocin, a potent antioxidant from saffron (Crocus sativus L.)

Crocin, a potent antioxidant obtained from saffron, shows anticancer activity in in vivo models. Unfortunately unfavorable physicochemical features compromise its use in topical therapy. The present study describes the preparation and characterization of nanostructured lipid dispersions as drug delivery systems for topical administration of crocin and the evaluation of antioxidant and antiproliferative effects of crocin once encapsulated into nanostructured lipid dispersions. Nanostructured lipid dispersions based on monoolein in mixture with sodium cholate and sodium caseinate have been characterized by cryo-TEM and PCS. Crocin permeation was evaluated in vitro by Franz cells, while the oxygen radical absorbance capacity assay was used to evaluate the antioxidant activity. Furthermore, the antiproliferative activity was tested in vitro by the MTT test using a human melanoma cell line. The emulsification of monoolein with sodium cholate and sodium caseinate led to dispersions of cubosomes, hexasomes, sponge systems and vesicles, depending on the employed emulsifiers. Permeation and shelf life studies demonstrated that nanostructured lipid dispersions enabled to control both rate of crocin diffusion through the skin and crocin degradation. The oxygen radical absorbance capacity assay pointed out an interesting and prolonged antioxidant activity of crocin while the MTT test showed an increase of crocin cytotoxic effect after incorporation in nanostructured lipid dispersions. This work has highlighted that nanostructured lipid dispersions can protect the labile molecule crocin from degradation, control its skin diffusion and prolong antioxidant activity, therefore suggesting the suitability of nanostructured lipid dispersions for crocin topical administration.

Anatomical substrates of cognitive and clinical dimensions in first episode schizophrenia

OBJECTIVE

To explore gray (GM) and white matter (WM) abnormalities and the relationships with neuropsychopathology in first-episode schizophrenia (FES).

METHOD

Nineteen patients with first episode of non-affective psychosis and 18 controls underwent a magnetic resonance voxel-based morphometry. Additionally, WM fractional anisotropy (FA) was calculated. For correlative analysis, symptoms and neuropsychological performances were scored by PANSS and by a comprehensive neuropsychological assessment respectively.

RESULTS

Patients showed significantly decreased volume of left temporal lobe and disarray of all major WM tracts. Disorganized PANSS factor was inversely related to left cerebellar GM volume (corrected P = 0.03) and to WM FA of the left cerebellum, inferior fronto-occipital fasciculi (IFOF), and inferior longitudinal fasciculi (corrected P < 0.05). PANSS negative factor was inversely related to FA in the IFOF and superior longitudinal fasciculi (corrected P < 0.05). Impairment in facial emotion identification showed associations with temporo-occipital GM volume decrease (corrected P = 0.003) and WM disarray of superior and middle temporal gyri, anterior thalamic radiation, and superior longitudinal fasciculi (corrected P < 0.05). Speed of processing and visual memory correlated with WM abnormalities in fronto-temporal tracts.

CONCLUSION

These results confirm how the structural development of key brain regions is related to neuropsychopathological dysfunction in FES, consistently with a neurodevelopmentally derived misconnection syndrome.

Regional personalized electrodes to select transcranial current stimulation target

Rationale: Personalizing transcranial stimulations promises to enhance beneficial effects for individual patients.

Objective: To stimulate specific cortical regions by developing a procedure to bend and position custom shaped electrodes; to probe the effects on cortical excitability produced when the properly customized electrode is targeting different cortical areas.

Method: An ad hoc neuronavigation procedure was developed to accurately shape and place the personalized electrodes on the basis of individual brain magnetic resonance images (MRI) on bilateral primary motor (M1) and somatosensory (S1) cortices. The transcranial alternating current stimulation (tACS) protocol published by Feurra et al. (2011b) was used to test the effects on cortical excitability of the personalized electrode when targeting S1 or M1.

Results: Neuronal excitability as evaluated by tACS was different when targeting M1 or S1, with the General Estimating Equation model indicating a clear tCS Effect (p < 0.001), and post hoc comparisons showing solely M1 20 Hz tACS to reduce M1 excitability with respect to baseline and other tACS conditions.

Conclusions: The present work indicates that specific cortical regions can be targeted by tCS properly shaping and positioning the stimulating electrode.

Significance: Through multimodal brain investigations continuous efforts in understanding the neuronal changes related to specific neurological or psychiatric diseases become more relevant as our ability to build the compensating interventions improves. An important step forward on this path is the ability to target the specific cortical area of interest, as shown in the present pilot work.

Gait analysis and cerebral volumes in Down's syndrome

The aim of this study was to look for a relationship between cerebral volumes computed using a voxel-based morphometry algorithm and walking patterns in individuals with Down's syndrome (DS), in order to investigate the origin of the motor problems in these subjects with a view to developing appropriate rehabilitation programmes. Nine children with DS underwent a gait analysis (GA) protocol that used a 3D motion analysis system, force plates and a video system, and magnetic resonance imaging (MRI). Analysis of GA graphs allowed a series of parameters to be defined and computed in order to quantify gait patterns. By combining some of the parameters it was possible to obtain a 3D description of gait in terms of distance from normal values. Finally, the results of cerebral volume analysis were compared with the gait patterns found. A strong relationship emerged between cerebellar vermis volume reduction and quality of gait and also between grey matter volume reduction of some cerebral areas and asymmetrical gait. An evaluation of high-level motor deficits, reflected in a lack or partial lack of proximal functions, is important in order to define a correct rehabilitation programme.

Time-varying cortical connectivity by high resolution EEG and directed transfer function: simulations and application to finger tapping data

The problem of the definition and evaluation of brain connectivity has become a central one in neuroscience during the latest years, as a way to understand the organization and interaction of cortical areas during the execution of cognitive or motor tasks. The method of the directed transfer function (DTF) is a frequency-domain approach to this problem, based on a multivariate autoregressive modeling of time series and on the concept of Granger causality. So far, all the connectivity estimations performed on cerebral electromagnetic signals were computed between signals gathered from the electric or magnetic sensors. However, the spreading of the potential from the cortex to the sensors makes it difficult to infer the relation between the spatial patterns on the sensor space and those on the cortical sites. In this paper we propose the use of the DTF method on cortical signals estimated from high resolution EEG recordings, which exhibit a higher spatial resolution than conventional cerebral electromagnetic measures. As main contributions of this work, we present the results of a wide simulation study, aiming to evaluate performances of DTF application on this kind of data, and a statistical analysis (via the ANOVA, analysis of variance) of the results obtained for different levels of signal to noise ratio and temporal length, as they have been systematically imposed on simulated signals. Finally, we provide an application to the estimation of cortical connectivity from high resolution EEG recordings related to finger tapping movements.

Solving the neuroimaging puzzle: the multimodal integration of neuroelectromagnetic and functional magnetic resonance recordings

In this chapter, advanced methods for the modeling of human cortical activity from combined high-resolution electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data are reviewed. These methods include a subject's multicompartment head model (scalp, skull, dura mater, cortex) constructed from magnetic resonance images, multidipole source model, and regularized linear inverse source estimates. Determination of the priors in the resolution of the linear inverse problem was performed with the use of information from the hemodynamic responses of the cortical areas as revealed by block-designed (strength of activated voxels) and event-related (coupling of activated voxels) fMRI. As an example, these methods were applied to EEG (128 electrodes) and fMRI data, which were recorded in separate sessions while normal subjects executed voluntary right one-digit movements.

Estimation of the cortical functional connectivity with the multimodal integration of high-resolution EEG and fMRI data by directed transfer function

Nowadays, several types of brain imaging device are available to provide images of the functional activity of the cerebral cortex based on hemodynamic, metabolic, or electromagnetic measurements. However, static images of brain regions activated during particular tasks do not convey the information of how these regions communicate with each other. In this study, advanced methods for the estimation of cortical connectivity from combined high-resolution electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data are presented. These methods include a subject's multicompartment head model (scalp, skull, dura mater, cortex) constructed from individual magnetic resonance images, multidipole source model, and regularized linear inverse source estimates of cortical current density. Determination of the priors in the resolution of the linear inverse problem was performed with the use of information from the hemodynamic responses of the cortical areas as revealed by block-designed (strength of activated voxels) fMRI. We estimate functional cortical connectivity by computing the directed transfer function (DTF) on the estimated cortical current density waveforms in regions of interest (ROIs) on the modeled cortical mantle. The proposed method was able to unveil the direction of the information flow between the cortical regions of interest, as it is directional in nature. Furthermore, this method allows to detect changes in the time course of information flow between cortical regions in different frequency bands. The reliability of these techniques was further demonstrated by elaboration of high-resolution EEG and fMRI signals collected during visually triggered finger movements in four healthy subjects. Connectivity patterns estimated for this task reveal an involvement of right parietal and bilateral premotor and prefrontal cortical areas. This cortical region involvement resembles that revealed in previous studies where visually triggered finger movements were analyzed with the use of separate EEG or fMRI measurements.

Assessing cortical functional connectivity by linear inverse estimation and directed transfer function: simulations and application to real data

OBJECTIVE

To test a technique called Directed Transfer Function (DTF) for the estimation of human cortical connectivity, by means of simulation study and human study, using high resolution EEG recordings related to finger movements.

METHODS

The method of the Directed Transfer Function (DTF) is a frequency-domain approach, based on a multivariate autoregressive modeling of time series and on the concept of Granger causality. Since the spreading of the potential from the cortex to the sensors makes it difficult to infer the relation between the spatial patterns on the sensor space and those on the cortical sites, we propose the use of the DTF method on cortical signals estimated from high resolution EEG recordings, which exhibit a higher spatial resolution than conventional cerebral electromagnetic measures. The simulation study was followed by an analysis of variance (ANOVA) of the results obtained for different levels of Signal to Noise Ratio (SNR) and temporal length, as they have been systematically imposed on simulated signals. The whole methodology was then applied to high resolution EEG data recorded during a visually paced finger movement.

RESULTS

The statistical analysis performed returns that during simulations, DTF is able to estimate correctly the imposed connectivity patterns under reasonable operative conditions, i.e. when data exhibit a SNR of at least 3 and a length of at least 75 s of non-consecutive recordings at 64 Hz of sampling rate, equivalent, more generally, to 4800 data samples.

CONCLUSIONS

Functional connectivity patterns of cortical activity can be effectively estimated under general conditions met in any practical EEG recordings, by combining high resolution EEG techniques, linear inverse estimation and the DTF method.

SIGNIFICANCE

The estimation of cortical connectivity can be performed not only with hemodynamic measurements, by using functional MRI recordings, but also with modern EEG recordings treated with advanced computational techniques.