Investigating the effects of transcranial alternating current stimulation on primary somatosensory cortex

Near-threshold tactile stimuli perception and somatosensory temporal discrimination threshold (STDT) are encoded in the primary somatosensory cortex (S1) and largely depend on alpha and beta S1 rhythm. Transcranial alternating current stimulation (tACS) is a non-invasive neurophysiological technique that allows cortical rhythm modulation. We investigated the effects of tACS delivered over S1 at alpha, beta, and gamma frequencies on near-threshold tactile stimuli perception and STDT, as well as phase-dependent tACS effects on near-threshold tactile stimuli perception in healthy subjects. In separate sessions, we tested the effects of different tACS montages, and tACS at the individualised S1 μ-alpha frequency peak, on STDT and near-threshold tactile stimuli perception. We found that tACS applied over S1 at alpha, beta, and gamma frequencies did not modify STDT or near-threshold tactile stimuli perception. Moreover, we did not detect effects of tACS phase or montage. Finally, tACS did not modify near-threshold tactile stimuli perception and STDT even when delivered at the individualised μ-alpha frequency peak. Our study showed that tACS does not alter near-threshold tactile stimuli or STDT, possibly due to the inability of tACS to activate deep S1 layers. Future investigations may clarify tACS effects over S1 in patients with focal dystonia, whose pathophysiology implicates increased STDT

Short-term plasticity of the motor cortex compensates for bradykinesia in Parkinson's disease

Patients with Parkinson's disease (PD) show impaired short-term potentiation (STP) mechanisms in the primary motor cortex (M1). However, the role played by this neurophysiological abnormality in bradykinesia pathophysiology is unknown. In this study, we used a multimodal neuromodulation approach to test whether defective STP contributes to bradykinesia. We evaluated STP by measuring motor-evoked potential facilitation during 5 Hz-repetitive transcranial magnetic stimulation (rTMS) and assessed repetitive finger tapping movements through kinematic techniques. Also, we used transcranial alternating current stimulation (tACS) to drive M1 oscillations and experimentally modulate bradykinesia. STP was assessed during tACS delivered at beta (β) and gamma (γ) frequency, and during sham-tACS. Data were compared to those recorded in a group of healthy subjects. In PD, we found that STP was impaired during sham- and γ-tACS, while it was restored during β-tACS. Importantly, the degree of STP impairment was associated with the severity of movement slowness and amplitude reduction. Moreover, β-tACS-related improvements in STP were linked to changes in movement slowness and intracortical GABA-A-ergic inhibition during stimulation, as assessed by short-interval intracortical inhibition (SICI). Patients with prominent STP amelioration had greater SICI reduction (cortical disinhibition) and less slowness worsening during β-tACS. Dopaminergic medications did not modify β-tACS effects. These data demonstrate that abnormal STP processes are involved in bradykinesia pathophysiology and return to normal levels when β oscillations increase. STP changes are likely mediated by modifications in GABA-A-ergic intracortical circuits and may represent a compensatory mechanism against β-induced bradykinesia in PD

Development of a rapid and eco-friendly UHPLC analytical method for the detection of histamine in fish products

We developed, validated, and confirmed with proficiency tests a fast ultra-high-performance liquid chromatography with diode array detector (UHPLC-DAD) method to determine histamine in fish and fishery products. The proposed method consists of two successive solid–liquid extractions: one with a dilute solution of perchloric acid (6%) and the second only with water. The instrumental analysis with UHPLC provides a very fast run time (only 6 min) with a retention time of approximately 4 min, a limit of quantification (LOQ) of 7.2 mg kg−1, a limit of detection (LOD) of 2.2 mg kg−1, a recovery around 100%, a relative standard deviation (RSD%) between 0.5 and 1.4, and an r2 of calibration curve equal to 0.9995. The method detected optimal values of the validation parameters and required a limited number of reagents in comparison to other methods reported in the literature. Furthermore, the method could detect histamine in a very short time compared with other methods. This method, in addition to being validated, precise, specific, and accurate, avoids wasting time, money, and resources, and limits the use of organic solvents

Trace elements in stomach oil of Scopoli's shearwater (Calonectris diomedea) from Linosa's colony

Calonectris diomedea is a colonial Procellariiform breeding on Mediterranean islands. The stomach oil produced during chick rearing is a peculiar trait of this species. The composition of the stomach oil is likely to reflect the composition of the prey ingested and might reveal the contaminants uptake with prey becoming a possible tool for the marine pollution monitoring. We examined the concentration of 15 trace elements by ICP-MS and direct mercury analyser. The principal component analysis revealed a heterogeneous pattern of metal concentration, showing a significant separation between samples collected 20 and 70 days after hatching. The data obtained in this work give preliminary information on the feeding habits and breeding ecology of Linosa's colony of Scopoli's shearwater. The trace metals variability found suggest that the stomach oil may have a role as trophic markers to understand predator-prey relationships and to have evidence on the accumulation of pollutants in the latter

High hydroxycinnamic acids contents in fennel honey produced in Southern Italy

A total of 122 honey samples (Apis mellifera ssp. Ligustica) collected from Southern Italy were examined for floral identification by melissopalynological examination and for polyphenols detection by an LC-ESI-OrbitrapTM -MS/MS method. The melissopalynological examination confirmed all the samples examined as fennel (Foeniculum vulgare) unifloral variety. The analytical method carried out for polyphenols detection showed satisfactory linearity and recovery values, achieved during the validation of the method. Very high amounts of flavonols (kaempferol and quercetin) and hydroxycinnamic acids (caffeic acid, chlorogenic acid and ferulic acid), were found in all the samples examined. Among the hydroxycinnamic acids group, caffeic acid showed the highest mean contents (865.90 ± 67.07 µg/kg). The results of this work confirmed the high presence of phenolic acids with strong free radical-scavenging activity in fennel products such as honey, suggesting their use to reduce oxidative stress

PRESENCE OF ANISAKIS PEGREFFII IN FARMED SEA BASS ( DICENTRARCHUS LABRAX L.) COMMERCIALIZED IN SOUTHERN ITALY: A FIRST REPORT

We examined 151 European sea bass (Dicentrarchus labrax L.) samples from farms and fish markets of Sicily (Southern Italy) for Anisakidae larvae detection. All the samples were examined by visual inspection and modified chloro-peptic digestion. Two nematode larvae were found in the viscera of only one European sea bass sample from a farm located in Greece (FAO 37.3), giving a total prevalence of infestation of 0.7%. No other parasites were found after chloro-peptic digestion of the samples. The larvae were morphologically ascribed, at genus level, to morphotypes I and molecularly identified as Anisakis pegreffii. To the best if our knowledge, this is the first report on the presence of anisakid parasites in farmed European sea bass of Mediterranean Sea. Our findings suggest that the risk of exposure to Anisakidae nematodes in farmed European sea bass remains very low. However, further data on Mediterranean farms are needed to have a detailed risk analysis

First Survey on the presence of anisakid parasites in farmed European sea bass and gilthead sea bream produced and marketed in Sicily

The Scientific Opinion of EFSA (2010) outlines as the only fish free of health risks related to Anisakidae parasites the farmed salmon, if reared in floating cages or on-shore cages and fed by feed with no live parasites. Otherwise, the food operator shall verify, by means of procedures approved by the competent authority, that the fishery products do not represent a health risk regarding the presence of live parasites. This opinion was confirmed by several studies conducted on farmed salmon in Norway (Angot and Brasseur, 1993, Aquaculture, 118: 339-344; Lunestad, 2003, J Food Prot, 66:122-124). The absence of anisakid parasites in farmed fish has also been found for other marine fish species such as European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) (Penalver et al., 2010 J Food Prot, 73:1332-1334). Currently there are low evidences on the prevalence of anisakid infestation in aquaculture fish produced and marketed in Italy. In this work, a sampling plan was carried out aimed at collecting different fish samples marketed in Sicily, to verify the presence and prevalence of anisakid parasites infestation. A total of 143 samples of sea bass and 110 samples of sea bream from Sicilian and Greek farms were examined: all the samples were of commercial size (over 200 g). The specimens were taken and stored refrigerated then transferred to the C.Re.N.A laboratories, where visual inspection of viscera and muscle was carried out. The negative samples were subjected to chloro-peptic digestion. The larvae found were subjected to morphological identification, through optical microscopy and molecular analysis by PCRRFLP method. The survey revealed the presence of two parasites belonging to the Anisakidae family, found inside the coelomatic cavity, only in a single sample of European sea bass from a single farm located in Greece, revealing a prevalence of infestation of 1.7%. The larvae were morphologically identified as belonging to the morphotype I of the genus Anisakis. Molecular investigations confirmed the larvae as Anisakis pegreffii species. No larvae were found in the samples of gilthead sea bream examined. The present work represents the first report on the presence of anisakid parasites in European sea bass. Our findings in farmed fish can be traced back to the aquaculture policies; however the prevalence of infestation in these productive realities remains very low. Furthermore, the results of this study suggest further investigations in order to have a comprehensive risk picture

Tetracycline Residues in Bovine Muscle and Liver Samples from Sicily (Southern Italy) by LC-MS/MS Method: A Six-Year Study

We examined a total of 369 bovine liver and muscle samples for the detection of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX) residues by implementation and validation of a LC-MS/MS method. The method showed good recovery values between 86% and 92% at three levels of concentrations. The linearity tests revealed r2 > 0.996 for all the tetracyclines examined. Furthermore, the Youden test revealed that the method was robust. Only 14.4% of the samples showed OTC and TC residues in a concentration range of 10.4–40.2 g kg1. No CTC and DOX residues were found in all the samples analyzed. Liver samples showed the highest average values (31.5 20.6 and 21.8 18.9 for OTC and TC, respectively). The results showed a low incidence of TCs in all the samples examined, in comparison with other studies reported in the literature. A significant decrease in TC residues frequency was found from 2013 (p < 0.05). This work reports for the first time epidemiological data on the presence of TC residues in liver and muscle samples of cattle farmed in Sicily (Southern Italy). The very low incidence of TC residues indicates a continuous improvement in farming techniques in Southern Italy, which is essential to ensure consumers’ protection