Copper Dependent Modulation of α-Synuclein Phosphorylation in Differentiated SHSY5Y Neuroblastoma Cells

Copper (Cu) dyshomeostasis plays a pivotal role in several neuropathologies, such as Parkinson's disease (PD). Metal accumulation in the central nervous system (CNS) could result in loss-of-function of proteins involved in Cu metabolism and redox cycling, generating reactive oxygen species (ROS). Moreover, neurodegenerative disorders imply the presence of an excess of misfolded proteins known to lead to neuronal damage. In PD, Cu accumulates in the brain, binds α-synuclein, and initiates its aggregation. We assessed the correlation between neuronal differentiation, Cu homeostasis regulation, and α-synuclein phosphorylation. At this purpose, we used differentiated SHSY5Y neuroblastoma cells to reproduce some of the characteristics of the dopaminergic neurons. Here, we reported that differentiated cells expressed a significantly higher amount of a copper transporter protein 1 (CTR1), increasing the copper uptake. Cells also showed a significantly more phosphorylated form of α-synuclein, further increased by copper treatment, without modifications in α-synuclein levels. This effect depended on the upregulation of the polo-like kinase 2 (PLK2), whereas the levels of the relative protein phosphatase 2A (PP2A) remained unvaried. No changes in the oxidative state of the cells were identified. The Cu dependent alteration of α-synuclein phosphorylation pattern might potentially offer new opportunities for clinical intervention.

Chemotrophic profiling of prokaryotic communities thriving on organic and mineral nutrients in a submerged coastal cave

The geothermal system of the Salento peninsula (Italy) is characterized by the presence of many hydrogen sulfide-rich underground waters and thermal springs. We focused our attention on the submerged section of Zinzulùsa (Castro, Italy), a cave of both naturalistic and archaeological interest. In pioneer studies, some hypotheses about the origin of the sulfurous waters of this area were proposed. The most accredited one is that sulfate-enriched waters of marine origin infiltrate deep along bands with greater permeability, and warm-up going upwards, due to the geothermal gradient. During their route, marine waters interact with organic deposits and generate hydrogen sulfide as a result of sulfate reduction. To date, no studies have been conducted to elucidate the hydrogen sulfide origin in this site. The nature of reducing power and energy sources supporting microbial life in this submerged habitat is currently unknown. Here we present a multidisciplinary experimental approach aimed at defining geochemical features and microbiological diversity of the submerged habitat of Zinzulùsa cave. Our integrated data provide strong evidence that the sulfate content of the marine water and the activity of sulfate-reducing bacteria may account for the hydrogen sulfide content of the thermal springs. Anaerobic, sulfate-reducing, thermophilic Thermodesulfovibrio and hyperthermophilic Fervidobacterium genera show a high percentage contribution in 16S rRNA gene metabarcoding analyses, despite the mesophilic conditions of the sampling site. Besides, supported by PICRUSt functional analysis, we propose a chemotrophic model in which hydrocarbon deposits, entrapped in the stratifications of the seafloor, may be exploited by anaerobic oil-degrading bacteria as carbon and energy sources to sustain efficient hydrogen, sulfur, and nitrogen biogeochemical cycles. The Zinzulùsa hydrothermal site represents an ecosystem useful to obtain new insights into prokaryotic mutual interactions in oligotrophic and aphotic conditions, which constitute the largest environment of the biosphere.

Investigations of byzantine wall paintings in the abbey of Santa Maria di Cerrate (Italy) in view of their restoration

In this paper, diagnostic analyses on 12th-13th century byzantine wall paintings in the abbey of Santa Maria di Cerrate (Southern Italy) were carried out preparatory to restoration work promoted by FAI (Fondo Ambiente Italiano). Both the pigments and the areas with a bleaching alteration in the frescoes were analysed using the energy dispersive X-ray fluorescence, the Raman spectroscopy and the scanning electron microscopy equipped with energy dispersive X-ray spectrometer. In particular, ED-XRF analyses were performed in situ on wall paintings, while Raman spectroscopy and SEM-EDX were accomplished on frescoes fragments. The results obtained allowed to determine the chemical composition of the pigments, helping to identify the original parts of the frescoes from the retouched ones. The work also provided important information about the historical-artistic context of the abbey. Archaeometric investigations have indeed revealed the pictorial technique used for the wall paintings of the abbey, as well as the presence of some very valuable pigments, such as lapis lazuli blue.

A silver nanoparticle-poly(methyl methacrylate) based colorimetric sensor for the detection of hydrogen peroxide

A colorimetric sensor based on nanoparticles was developed for the detection of hydrogen peroxide. Nanoparticles were made using small sheets of poly(methyl methacrylate) (PMMA) and silver nitrate. The optical properties of the solution were characterized by spectrophotometer using the localized surface plasmon resonance (LSPR) phenomenon. The shape and size of the nanoparticles were obtained using a transmission electron microscope (TEM). Silver-poly(methyl methacrylate) nanoparticles solution (AgNP-PMMA) proved to be particularly sensitive to hydrogen peroxide compared to other analytes. This sensor provided a quick, practical and easy tool to detect hydrogen peroxide.

Ethane-Bridged Bisporphyrin Conformational Changes As an Effective Analytical Tool for Nonenzymatic Detection of Urea in the Physiological Range

Conformational switching induced in ethane-bridged bisporphyrins was used as a sensitive transduction method for revealing the presence of urea dissolved in water via nonenzymatic approach. Bisporphyrins were deposited on solid quartz slides by means of the spin-coating method. Molecular conformations of Zn and Ni monometalated bis-porphyrins were influenced by water solvated urea molecules and their fluorescence emission was modulated by the urea concentration. Absorption, fluorescence and Raman spectroscopies allowed the identification of supramolecular processes, which are responsible for host-guest interaction between the active layers and urea molecules. A high selectivity of the sensing mechanism was highlighted upon testing the spectroscopic responses of bis-porphyrin films to citrulline and glutamine used as interfering agents. Additionally, potential applicability was demonstrated by quantifying the urea concentration in real physiological samples proposing this new approach as a valuable alternative analytical procedure to the traditionally used enzymatic methods.

Copper and ceruloplasmin dyshomeostasis in serum and cerebrospinal fluid of multiple sclerosis subjects

Although many studies have been carried out in order to understand the implication of copper (Cu) in the pathogenesis of multiple sclerosis (MS), the exact role that this metal plays in the disease is not still clear. Because of the lack of information in this subject, the present study compared the serum and cerebrospinal (CSF) levels of copper in MS patients in respect to a control group, matched for age and sex, finding a significant increase of metal concentrations, in both biological fluids of MS subjects. To confirm the possible impairment of Cu metabolism, we analyzed ceruloplasmin (Cp) level and activity, seeing as this protein is an established peripheral marker in diseases associated with Cu imbalance. By comparing these two parameters between control and MS subjects, we found an increase of Cp levels, associated with a decrease in Cp activity, in the second group. By analysing these data, free copper levels were calculated, significantly increased in serum of MS subjects; the increase in free copper could be one of the predisposing factors responsible for the Cu altered levels in CSF of MS patients. At the same time, this alteration could be attributable to the inability to incorporate Cu by Cp, probably due to the high oxidative environment found in serum of MS patients. Overall, all these copper alterations may play a role in MS pathogenesis.

Colloidal solution of silver nanoparticles for label-free colorimetric sensing of ammonia in aqueous solutions

Silver nanoparticles were synthesized in the presence of saccharides and ammonia (NH3) in the concentration range from 10-2 to 103 ppm to develop an optical sensor for NH3 in aqueous solutions. Ammonia affects the features of the nanoparticles obtained in a concentration-dependent manner as determined by UV-vis absorption analysis and TEM observations. Structural and morphological analysis provides the basis for the production of a colorimetric label-free sensor for ammonia. Overall, surface plasmon resonance increases when ammonia concentration rises, although the functional trend is not the same over the entire investigated ammonia concentration range. Three different ranges have been identified: very low ammonia concentrations from 0.01 to 0.2 ppm, high ammonia concentrations from 20 to 350 ppm and, most importantly, the intermediate or physiological range of ammonia from 0.5 to 10 ppm.

Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution.

Enhanced electrical conductivity of collagen films through long-range aligned iron oxide nanoparticles

The development of biocompatible collagen substrates able to conduct electric current along specific pathways represent an appealing issue in tissue engineering, since it is well known that electrical stimuli significantly affects important cell behaviour, such as proliferation, differentiation, directional migration, and, therefore, tissue regeneration. In this work, a cheap and easy approach was proposed to produce collagen-based films exhibiting enhanced electrical conductivity, through the simple manipulation of a weak external magnetic trigger. Paramagnetic iron oxide nanoparticles (NPs) capped by a biocompatible polyethylene-glycol coating were synthetized by a co-precipitation and solvothermic method and sprayed onto a collagen suspension. The system was then subjected to a static external magnetic field in order to conveniently tune NPs organization. Under the action of the external stimulus, NPs were induced to orient along the magnetic field lines, forming long-range aligned micropatterns within the collagen matrix. Drying of the substrate following water evaporation permanently blocked the magnetic architecture produced, thereby preserving NPs organization even after magnetic field removal. Electrical conductivity measurements clearly showed that the presence of such a magnetic framework endowed collagen with marked conductive properties in specific directions. The biocompatibility of the paramagnetic collagen films was also demonstrated by MTT cell cytotoxicity test.

A simple approach to synthetize folic acid decorated magnetite@SiO2 nanostructures for hyperthermia applications

Folic Acid decorated SPIONs selective internalization was monitored by an innovative Ellipsometry imaging approach.

High ordered biomineralization induced by carbon nanoparticles in the sea urchin Paracentrotus lividus

A surprising and unexpected biomineralization process was observed during toxicological assessment of carbon nanoparticles on Paracentrotus lividus (sea urchin) pluteus larvae. The larvae activate a process of defense against external material, by incorporating the nanoparticles into microstructures of aragonite similarly to pearl oysters. Aiming at a better understanding of this phenomenon, the larvae were exposed to increasing concentrations of carbon nanoparticles and the biomineralization products were analyzed by electron microscopy, x-ray diffraction and Raman spectroscopy. In order to evaluate the possible influence of Sp-CyP-1 expression on this biomineralization process by larvae, analyses of gene expression (Sp-CyP-1) and calcein labeling were performed. Overall, we report experimental evidence about the capability of carbon nanoparticles to induce an increment of Sp-CyP-1 expression with the consequent activation of a biomineralization process leading to the production of a new pearl-like biomaterial never previously observed in sea urchins.

Synthesis of tailored phthalocyanines and their application as spin coated films in volatile organic compound detection

29H,31H-(2,4-di-t-amylphenoxy)phthalocyanine, Zn (II) tetra-4-(2,4-di-t-amylphenoxy) phthalocyanine and Zn (II) tris-(2,4-di-t-amylphenoxy)-[4-(4-mercapto-phenyliminomethyl)- phenoxy]phthalocyanine were synthesized and their molecular structures were confirmed by LC-MS, 1 H NMR, FT-IR and UV-vis spectra. Spin coated layers of these phthalocyanines have been used as optochemically interactive materials for volatile organic compounds detection in the UV-vis spectral range. The results show a good sensitivity and selectivity depending on both the metal and the peripheral substituents. Optical sensitivity towards tert-butylamine, diethylamine, dibutylamine, 2-butanone and acetic acid has been monitored.

Stress response induced by carbon nanoparticles in Paracentrotus lividus

Members of the 14-3-3 protein family are involved in many important cellular events, including stress response, survival and apoptosis. Genes of the 14-3-3 family are conserved from plants to humans, and some members are responsive to UV radiation. Despite the high rate of pollution generated by nano-pollutants, up to now their toxic effect on development is totally obscure. Embryos treated with carbon nanoparticles, RNA preparation, retro-transcription and quantitative real-time PCR. In response to carbon nano-particles exposure, the embryos collected 24 h later showed a 3,07-fold at 5x10(12) p and a 1,58-fold at 2.5x10(13) p and a 1,92-fold at 2.5x10(14) p increase in Pl14-3-3ε transcript levels compared with controls. The Pl14-3-3ε mRNA delocalization parallels the failure in archenteron elongation observed morphologically, as well as the lack of specific endoderm markers. Here, we report the isolation of the complete cDNA encoding the 14-3-3 epsilon isoform from Paracentrotus lividus sea urchin embryos, referred to as Pl14-3-3ε. Pl14-3-3ε mRNA levels were measured by RT-PCR during development and found to increase from the mesenchyme blastula to the prism stage. Our results confirm the involvement of 14-3-3ε in the stress response elicited by carbon nano-particles.

Monitoring of total and bioavailable heavy metals concentration in agricultural soils

The aim of this paper is to evaluate total and bioavailable concentration of heavy metals in agricultural soils in order to estimate their distribution, to identify the possible correlations among toxic elements and the pollution sources, to distinguish the samples in relation to sampling site or to sampling depth, and to evaluate the available fraction providing information about the risky for plants. In particular, we reinvestigated total concentrations of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, V, and Zn and available concentrations of As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, and Zn in soil from Apulia (Southern Italy). Analytical results showed that total concentrations, for all soils, are in the range permitted by regulations in force in Italy, but some soils evidence slight enrichment of Cd, Cr, Cu, Pb, and Zn. All the heavy metals in the available fraction were below the detection limits of the analytical techniques used except Cu, Ni, Pb, and Zn.

Non-functionalized silver nanoparticles for a localized surface plasmon resonance-based glucose sensor

The optical properties of non-functionalized silver nanoparticles in ethanol solution have been analyzed and a progressive shift of localized surface plasmon resonances caused by the adding of increasing quantities of glucose has been observed. To understand this occurrence, the interaction of glucose molecules with the silver nanoparticle surface has been investigated using Raman spectroscopy. In addition, high resolution transmission electron microscopy shows the presence of superstructures on the silver nanoparticle surface that can be imputed to the presence of glucose.

Investigation of paroxysmal dystonia in a patient with multiple sclerosis: a transcranial magnetic stimulation study

OBJECTIVE

To study the pathogenesis of paroxysmal dystonia affecting the right body side in a patient with a demyelinating lesion in the descending motor pathways, also involving the basal ganglia.

METHODS

Single-pulse transcranial magnetic stimulation (TMS) was applied to study motor evoked potentials (MEPs) and the following silent periods (SPs) in the first dorsal interosseous muscle (FDI) of both sides and in the right extensor carpi radialis muscle (ECR) during voluntary contractions performed outside the dystonic attacks. During the dystonic paroxysms, single-pulse TMS was used to investigate the time course of MEPs and SPs in both FDI and ECR of the right side. Furthermore, paired-pulse TMS was applied at rest to investigate short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in both FDI muscles.

RESULTS

At rest SICI and ICF were normal in both motor cortices. During voluntary contraction the MEP was smaller and the SP was longer in the affected FDI than in the contralateral. During the paroxysms, the MEPs and SPs were suppressed in comparison with the responses elicited during voluntary contraction.

CONCLUSIONS

These results fit well with the theory of ephaptic excitement of corticospinal axons for the pathogenesis of paroxysmal dystonia due to a demyelinating lesion.

SIGNIFICANCE

Identification of the mechanisms underlying paroxysmal dystonia in demyelinating disorders extends our knowledge on the pathophysiology of dystonia.

Organic pollutants (PAHs, PCBs) in sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy)

Polychlorinated biphenyls (PCBs) and 17 parent polycyclic aromatic hydrocarbons (PAHs) were determined in surface sediments from nine stations in the Mar Piccolo of Taranto (Ionian Sea, Southern Italy). Total PAH concentrations ranged from 380 to 12,750 microg/kg d.w., while total PCB levels ranged from 2 to 1684 microg/kg d.w.; this values were higher than those found in others marine coastal areas of the Mediterranean Sea. For PAHs, low molecular weight/high molecular weight, phenanthrene/anthracene and fluoranthene/pyrene ratio were used for discriminating between pyrolitic and petroleum origin. Results showed that PAHs were mainly of pyrolitic origin. PCB and PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL, TEL-PEL indexes) for evaluation probable toxic effects on marine organism. Finally, ERM and PEL quotients were used to evaluate the degree to which chemicals exceed guidelines. Results suggest an ecotoxicological risk for benthic organisms mainly in the first inlet, where high concentrations of PCBs were found in sediments influenced by harbour activities.

Heavy Metals in Marine Sediments from the Mar Piccolo of Taranto (Ionian Sea, Southern Italy)

Heavy metals concentrations (Cd, Cu, Hg, Pb, Sn and Zn) have been determined monthly in surface sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy. a semi-enclosed marine basin very important from a mussel-culture point of view. In sediments, sulphides, percentage of organic carbon and redox potential were also determined to show possible correlations between metals levels and redox characteristics of marine sediments. Analytical results, elaborated by multivariate statistical techniques, confirm that sediments collected in the first inlet of Mar Piccolo, where shipbuilding activities are present, have a contamination level greater than those collected in the second inlet. For each metal, the geoaccumulation index (Igeo) has been calculated as criterion to evaluate both pollution levels and metals enrichment in examined sediments: Igeo values confirm that the first inlet is an moderately polluted area from Hg and Pb. In any case, high sulphide concentrations and negative values of redox potentials bring to a conclusion that metals are present in sediments, mainly as insoluble sulphides and then as not bioavailable compounds for filter feeders organisms such as mussels.

Testing the photosynthetic bacterium Rhodobacter sphaeroides as heavy metal removal tool

We present some preliminary results relevant to the ability of the purple non-sulphur bacterium Rhodobacter sphaeroides strain R26.1 to sequester heavy metals from contaminated growth media. The microorganism was chosen because of its significant tolerance to relatively high concentrations of the investigated ions Ni2+, Co2+, CrO4(2-), and MoO4(2-). In this paper the optimized conditions for the bacterial growth and the sample preparation used to infer the ability of the microorganism to cope with metal pollutants are presented. Elemental analysis has been performed by inductively coupled plasma atomic emission spectrometry previous mineralization of samples by a microwave system.

Creutzfeldt-Jakob disease presenting as corticobasal degeneration: a neurophysiological study

Creutzfeldt-Jakob disease (CJD) can occasionally present with a clinical picture resembling a corticobasal degeneration (CBD). Transcallosal inhibition, as tested by focal transcranial magnetic stimulation, is frequently absent or highly disrupted in CBD patients. We report a case of CJD presenting at the beginning of the disease as a CBD in which the ipsilateral silent period (iSP) was present and well detectable. This brief report shows that study of the iSP may be a useful diagnostic tool in order to differentiate CBD from syndromes presenting with similar clinical features.

Bilateral impairment of intracortical inhibition in delayed-onset posthemiplegic dystonia: pathophysiological implications

OBJECTIVE

To study short interval intracortical inhibition (SICI) in a rare patient with segmental dystonia of the left upper limb due to a vascular lesion in the contralateral putamen without corticospinal tract involvement.

METHODS

Paired-pulse transcranial magnetic stimulation (TMS) was applied to both hemispheres in a conditioning-test paradigm. Six interstimulus intervals (ISIs) and 4 conditioning stimulation intensities were investigated in two separate sessions.

RESULTS

Motor evoked potentials upon single-pulse TMS were within the normal range, whereas paired-pulse TMS revealed major changes in cortical excitability, proving that SICI was bilaterally absent.

CONCLUSIONS

The bilateral impairment of SICI cannot be considered the cause of dystonic contractions, but just a predisposing factor.

SIGNIFICANCE

The absence of SICI might be regarded as a condition able to promote maladaptive plastic changes triggered by focal lesions in the putamen.

Natural Sources and Heavy Metals

PTS, PM10 and PM2.5 samples have been collected at a rural site of south-east Italy (40 degrees 20' 13" N; 18 degrees 6' 47" E) from June to October, 2004 to investigate natural and anthropogenic contributions on particulate matter and heavy metal mass concentrations. It is shown that sharp-peak particulate-matter concentrations have been recorded during most African dust outbreaks occurred over south-east Italy. In particular, PM10 concentrations exceeding the 24-hour limit value of 50 microg/m3 have been monitored during dust events. Al, Cd, Cr, Cu, Fe, Mn, V, Ni, Pb, and Zn metal concentrations have been evaluated by an inductively coupled plasma atomic emission spectrometer and Al mass concentrations >500 ng/m3 have been observed in PTS and PM10 samples during the advection of African dust particles. Accordingly to geochemical calculations Al, Fe, and Mn, have a significant crustal origin while, Cd, Cu, Pb, and Zn are of anthropogenic origin. Moreover, Fe resulted predominant in the coarse particle fraction, while Ni, Pb, V, and Zn were predominant in the fine particle fraction. It is also shown that Cd, Mn, Ni, Pb, and V concentrations never exceeded guide and/or limit values recommended by the World Health Organization and the European Council Directives.

Heavy Metals in PM10 Sampled in the Urban Area of Campi Salentina (Apulia, Southern Italy)

The following paper shows results of PM10 level and Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn concentrations present in this fraction for filters collected in the urban area of Campi Salentina (Apulia, Southern Italy) in 2004 in order to inquire into air quality. PM10 and lead concentrations did not exceed the standard values sanctioned by Italian Legislature with average values equal to 36.54 +/- 14.57 microg x m(-3) and 9.19 +/- 5.24 ng x m(-3) respectively. Significant correlations have been found between the pairs Fe-Mn, Ni-V, Cr-Ni and Cd-Cr. This suggests that these metals have a similar pollution source probably due to metallurgical activity. Multivariate statistical analysis showed that it is possible to distinguish the PM10 samples collected in sampling periods with different meteorological conditions. Indeed, metals concentration increases for samples characterized by scarce rains or by winds prevailing from North or North-West and is reduced due to different meteorological conditions, although there are some exceptions.

Botulinum toxin changes intrafusal feedback in dystonia: A study with the tonic vibration reflex

To investigate the possible role of botulinum toxin (BT-A) injection in reducing muscle afferent feedback, we evaluated electrophysiologically 10 right-handed patients with writer's cramp before and 3 weeks after treatment. The ratio between pre- and postinjection values of maximal M-wave (M-max), maximal voluntary contraction (MVC), and tonic vibration reflex (TVR) were measured in the injected muscles (wrist flexors or extensors). In all the subjects, BT-A injection reduced the TVR more than the M-max and MVC (mean ratio +/- SD: TVR, 0.24 +/- 0.22; MVC, 0.59 +/- 0.32; M-max, 0.68 +/- 0.24; P = 0.003). Long-term evaluation of 2 patients disclosed that, after 7 months, when some clinical benefits persisted, M-max and MVC had fully recovered, whereas the TVR was still depressed. This special sensitivity of the TVR to suppression by BT-A injection could be mediated by the chemodenervation of intrafusal muscle fibers, leading to a reduction in spindle inflow to the central nervous system during vibration. The action on intrafusal fibers could alter sensorimotor integration, thus contributing to the clinical benefits of BT-A injection.

Distribution and Occurence of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments from the Mar Grande and Gulf of Taranto (Ionian Sea, Southern Italy)

Marine sediments from the Mar Grande and Gulf of Taranto were analysed for 17 parent PAHs, with molecular weight from 128 to 278 Daltons. The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). Total PAHs content in sediments ranged from 464 to 12522 microg kg(-1) dry wt for Mar Grande and from 593 to 72275 microg kg(-1) dry wt for Gulf of Taranto. The analytical results were compared with the published results for other coastal areas in the Mediterranean Sea. PAHs levels in the Gulf of Taranto sediments were the highest in the Mediterranean sea, while PAHs concentrations in Mar Grande were higher than the ones reported in the Adriatic and Cretan Sea and with the same order of magnitude of the ones known for coastal areas of the Western and the Eastern Mediterranean Sea. PAHs concentration ratios were consistent with the main source of these compounds, in most areas, being pyrolysis. Based on the comparison of both the individual and the total PAHs concentrations with proposed sediment quality guidelines, the acute biological effects on the marine organisms were probable, especially for the Gulf of Taranto, in which almost all PAHs concentrations in sediments were higher than the guidelines limit values. The statistical analysis effected by HCA and PCA methods was used in order to classify sediment samples and to identify accumulation areas.

Particulate matter characterization at a coastal site in south-eastern Italy

Several samples of airborne particulate matter (PM), collected from 6th November to 6th December 2003 at a coastal site in the south-east of Italy, have been analyzed by different techniques to characterize elemental composition and morphological properties of the inorganic PM fraction and obtain preliminary results on anthropogenic contributions. Al, Cr, Cu, Fe, Mn, V, Pb, Ti, Ca and Zn mass concentrations, evaluated by an inductively coupled plasma atomic emission spectrometer, account for up to l% of the bulk PM mass in the investigated samples. According to geochemical calculations, Ca, Al, Fe and Mn are predominantly of crustal origin, while Cr, Cu, Pb, V, Ti and Zn heavy metals are of anthropogenic origin. Ion chromatography analyses have identified sulfate (SO(4)(2-)) nitrate (NO(3)(-)), sodium (Na(+)), and ammonium (NH(4)(+)) as the main ionic components accounting for up to 38% of the total PM mass and up to 90% of the total ionic mass. Besides ion chromatography, X-ray energy dispersive (EDX) microanalyses have revealed the high variability of Cl: its weight concentration varies from about 24% to below the detection limit (>or=0.5%) in the investigated samples. The marked anti-correlation between the excess of S and the Cl/Na ratio has allowed inferring that reactions between sea salt particles and acidic sulfates, which liberate HCl gas to the atmosphere leaving particles enriched in non-sea-salt sulfates, have significantly contributed to chloride depletion. Morphological analyses by scanning electron microscopy have shown that about 90% of the total sampled particles have a diameter <or=5 microm.

Geographical origin and breed discrimination of Apulian lamb meat samples by means of analytical and spectroscopic determinations

With the aim of finding parameters capable of characterizing meat according to geographical origin, twenty-five lamb meat samples from three areas located in Apulia (Southern Italy) were analysed for moisture, ash, fat and protein content, stable isotope ratios ((15)N/(14)N and (13)C/(12)C), major elements (Ca, Mg, Na, K) and trace metals (Zn, Cu, Fe, Cr). (1)H high resolution magic angle spinning (HR-MAS) NMR spectra were also obtained for all the samples. The advantages of the (1)H HR-MAS NMR technique are that sample preparation is easy, since the spectrum is obtained directly on the minced solid sample, and that information is acquired for a large number of metabolites (amino acids, fatty acids, sugars, etc.). The application of multivariate statistical analysis to two data sets containing tissue composition results together with the metals contents and (1)H HR-MAS NMR spectral data together with isotope ratios, respectively, provided in both cases a satisfactory origin differentiation of lamb meat samples.

Underground waters quality in the province of Lecce (Apulia, Southern Italy)

This paper shows the results of underground waters last monitoring in the province of Lecce (Apulia, Southern Italy). We carried out the physical-chemical characterization of the aquifers and their classification in accordance to limit values sanctioned by Italian legislation in force, by European directives and by FAO, in order to define their quality and to establish their possible use for drinkable and irrigation purposes. The attention has been focused on salinity evaluation and underground waters contamination phenomena, due to sea-water intrusion and to the use of fertilizers. Salinity and nitrates concentrations are high in a few wells. Iron and manganese concentrations are very high for almost every sample and this is due to corrosion phenomena of artesian wells metallic structure. For a better interpretation of data, multivariate statistical analysis has been used, in order to obtain the correlation among analytical results, soils hydro-geological properties and anthropic conditions.

PM-10 and Heavy Metals in Particulate Matter of the Province of Lecce (Apulia, Southern Italy)

This paper shows the results of a preliminary study of air monitoring in the province of Lecce (Apulia, Southern Italy). In particular, the attention has been focused on the determination of the PM-10 level and of the concentration of nine metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) present on the filters which were collected in two towns (Lecce and Campi Salentina) from 2002 until 2003. The metals have been chosen on the basis of their toxicity and of their possible use as chemical tracers. The results have proved that PM-10 values and metals concentrations did not show substantial difference between the two towns and that PM-10 level and lead concentration are below the limit established by Italian law in force. The experiments have demonstrated a high correlation between iron and manganese in both sampling sites; this could be attributed to pollution of metallurgical origin. Multivariate statistical analysis, carried out by HCA and PCA methods, has been used in order to differentiate samples in relation to sampling sites, sampling period and meteorological conditions.

Distribution and speciation of metals in surface sediments of Taranto [corrected] gulf (Ionian Sea, Southern Italy)

Concentrations of metals (Al, Fe, Ti, Ni, Mn, Cr, Zn, Cu, Pb) were determined in surface sediments from Taranto gulf (Ionian Sea, Southern Italy) in order to assess the distribution and the bioavailability of metals. Total metal content and speciation of Fe, Ni, Mn, Zn, Cu and Pb were determined. Sediment cores were also sampled in some stations of particular interest. The analytical results show that metals distribution does not show significant variations in relation to depth. Metal distribution in the Taranto gulf is mainly influenced by industrial wastes from Taranto town, by rivers of the Basilicata region and by prevailing anticlockwise marine currents. These factors cause an accumulation of metals in the sediments near to the coasts of Calabria. The statistical analysis, effected by HCA and PCA methods, can be considered a good starting point in order to classify sediment samples and to locate accumulation areas. Metal speciation shows that Fe, Ni and Zn are present in sediments mainly as sulphides, Mn is present principally in an ion-exchange form or bound to carbonate, while Cu and Pb are mainly present in the fraction bounds to humic acids.

Relaxation from a voluntary contraction is preceded by increased excitability of motor cortical inhibitory circuits

Termination of a muscle contraction is as important a part of movement as muscle activation yet the mechanisms responsible are less well understood. In the present experiments we examined the possible role of intracortical inhibitory circuits in terminating a 20% maximum isometric contraction of the first dorsal interosseous muscle (FDI) in eight healthy subjects. Subjects performed the task simultaneously with both hands and received single or pairs (at an interstimulus interval of 3 ms to evaluate short interval intracortical inhibition, SICI) of transcranial magnetic stimuli (TMS) via a focal coil over the motor hand area of the left hemisphere at different times before and after the onset of relaxation. The amplitude of the motor-evoked potential (MEP) following a single or a pair of TMS pulses was measured in the right FDI and plotted relative to the onset of relaxation as estimated from the surface electromyogram (EMG) of the left FDI. MEPs were larger during contraction than after relaxation whereas SICI was absent during contraction and reappeared after relaxation. We found that in all subjects, the time course of MEP changes during relaxation was closely fitted by a Boltzmann sigmoidal curve which allowed us to estimate the mean MEP amplitudes as well as the ratio of the amplitudes after single or pairs of TMS pulses (i.e.%SICI) at any time in the task. The data showed that the amplitude of MEPs to single pulse TMS had started to decline at about the same time as the onset of EMG silence. Furthermore, the size of the MEPs evoked by paired pulses decreased up to 30 ms beforehand. The latter suggests that an increase in SICI occurs prior to the onset of MEP changes, and hence that increased cortical inhibition may play a role in suppressing corticospinal excitability during relaxation. A subsidiary experiment showed that the time relations of changes in SICI and MEP were unchanged by a period of 10 min training on the task.

Muscle relaxation is impaired in dystonia: A reaction time study

A simple visual reaction time (RT) paradigm was used to investigate whether the velocity of relaxation is impaired in dystonia. In 16 subjects with a clinical diagnosis of adult-onset focal, segmental or multifocal dystonia and in 15 age-matched normal controls, the relaxation reaction time (R-RT) and the contraction reaction time (C-RT) were compared across different tasks involving the flexor carpi radialis (FCR), biceps brachii (BB) and triceps brachii (TR) arm muscles. In normal controls, the latency of EMG termination (R-RT) was significantly shorter than the latency of electromyographic (EMG) onset (C-RT) in the BB and TR muscles, but not in the FCR muscle. In dystonic patients, the latency of EMG termination (R-RT) was significantly longer than the latency of EMG onset (C-RT) in the FCR and BB muscles. No significant difference of the C-RT was observed between patients and controls whereas the R-RT was prolonged significantly in the BB and TR muscles of patients with dystonia and almost significantly in the FCR muscle. This study indicates that muscle relaxation is abnormal in patients with focal (multifocal or segmental) dystonia. The impaired muscle relaxation may contribute to the longer overlap of agonist-antagonist activities (co-contraction) typically observed in dystonia and to the slowness of voluntary movement sequencing.

Suppression of the transcallosal motor output: a transcranial magnetic stimulation study in healthy subjects

We tested the hypothesis that transcranial magnetic stimulation (TMS), in addition to its inhibitory action on the corticospinal output, can also exert some inhibitory effect on the transcallosal system connecting the two motor cortices. In seven normal subjects, instructed to keep their right opponens pollicis (OP) muscle fully relaxed and their left OP muscle voluntarily contracted, we used a paired-pulse TMS protocol, to stimulate the left motor cortex. We evaluated the effect of low-intensity conditioning stimulation on the ipsilateral silent period (iSP) elicited by the subsequent test stimulus. Compelling evidence exists to support that this iSP is mediated by the activation of transcallosal motor fibres. Simultaneously, the inhibition of the motor evoked potential (MEP) in the right OP muscle was also investigated. At the interstimulus interval (ISI) of 3 ms, the iSP was significantly (P<0.0001, repeated-measures ANOVA) suppressed by conditioning intensities ranging from 1.2 to 0.6 of MEP threshold. The assessment of the time-course showed that iSP inhibition was present in all the tested subjects only at ISIs of 2 and 3 ms (for each subject P<0.05, repeated-measures ANOVA). Several findings suggest that the suppression of iSP is brought about by the activation of inhibitory mechanisms operating in the stimulated (left) motor cortex. We propose that the assessment of iSP suppression could be a method to study the excitability of intracortical inhibitory circuits in the affected hemisphere of patients with unilateral damage of the corticospinal tract.

Impairment of transcallosal inhibition in patients with corticobasal degeneration

OBJECTIVE

To evaluate the motor function of the transcallosal pathways in patients with clinical diagnosis of corticobasal degeneration (CBD).

METHODS

In a group of 7 patients (4 males, 3 females; mean age 70.6 years) with clinical diagnosis of probable CBD (and in 8 age-matched normal controls) we evaluated the suppression of the ongoing voluntary EMG activity in the opponens pollicis muscle induced by focal transcranial magnetic stimulation (TMS) of the ipsilateral hand motor cortex. Such ipsilateral silent period (iSP) is mediated from one motor cortex to the contralateral side via a transcallosal pathway. In addition, CBD patients were investigated with magnetic resonance imaging (MRI) and neuropsychological assessment.

RESULTS

iSP was normal in 4 CBD patients, while it was bilaterally disrupted in the other 3. MRI showed an atrophy of the corpus callosum (middle-posterior part of the trunk) in the CBD patients with iSP disruption. Neuropsychological evaluation showed in patients with iSP impairment a decrease of verbal fluencies associated with an impairment of attentive function.

CONCLUSIONS

A proportion of CBD patients shows physiological evidence of impaired callosal motor function and atrophy of the corpus callosum on MRI, possibly correlated to dysphasic and cognitive disorders.

Relaxation in distal and proximal arm muscles: a reaction time study

OBJECTIVE

To investigate whether the same mechanisms underlie muscle relaxation in proximal and distal arm muscles of normal subjects.

METHODS

Fourteen healthy subjects were studied using a simple visual reaction time paradigm. Relaxation reaction time (R-RT) and contraction reaction time (C-RT) were compared across different tasks involving distal (first dorsal interosseus, FDI, flexor carpi radialis, FCR) and proximal (biceps brachii, BB, triceps brachii, TR) arm muscles. Changes of FCR H-reflex before and during voluntary relaxation were investigated in two subjects.

RESULTS

No significant difference was observed between R-RT and C-RT in the distal muscles. The R-RT was significantly shorter than C-RT in both the BB and TR muscles. The relaxation latency (R-RT) was significantly correlated to the subjects' age in all the muscles except the FDI. No inhibition of the FCR H-reflex could be observed in the 20 ms preceding muscle relaxation.

CONCLUSIONS

Our findings suggest that neural mechanisms contribute differently to the relaxation of muscles with a different functional role. Voluntary relaxation in distal arm muscles is mainly related to the reduction of motor cortical output, while in proximal muscles a spinal disfacilitation is also present and possibly sustained by the modulation of presynaptic inhibition.

Differential modulation of motor evoked potential and silent period by activation of intracortical inhibitory circuits

OBJECTIVES

To investigate the effect of activation of intracortical inhibitory circuits, as tested by short interval (3 ms) paired-pulse transcranial magnetic stimulation (TMS) with a conditioning-test paradigm, on the electromyographic (EMG) pause (silent period, SP) following the motor evoked potential (MEP) in normal subjects.

METHODS

SPs and MEPs were recorded from the right first dorsal interosseous (FDI) muscle during a tonic voluntary contraction (from 70 to 90% of the maximum). Using a focal coil, we compared the SP duration after single-pulse TMS, paired-pulse TMS and single-pulse TMS of reduced intensity such as to evoke MEPs matched in size to the conditioned ones after paired-pulse TMS. In addition, we compared in a control experiment the duration of the SP following matched size MEPs evoked, respectively, by focal TMS with preferential activation of indirect I1- or I3-waves.

RESULTS

SP duration after paired-pulse TMS was significantly longer than after single-pulse TMS evoking MEPs of a similar size. In no case the SP duration was longer when focal TMS preferentially activated I1-waves.

CONCLUSIONS

The conditioning sub-threshold stimulus is more powerful in reducing the MEP size than in cutting down the subsequent EMG silence, suggesting that the neural circuits underlying MEP and SP are, at least in part, different.

Abnormalities of sensorimotor integration in focal dystonia: a transcranial magnetic stimulation study

It has been postulated that sensorimotor integration is abnormal in dystonia. We investigated changes in motor cortical excitability induced by peripheral stimulation in patients with focal hand dystonia (12 patients with hand cramps) and with cervical dystonia (nine with spasmodic torticollis) compared with 16 age-matched normal controls. Motor evoked potentials (MEP) to focal (figure-of-eight coil) transcranial magnetic stimulation of the hand area were recorded from the right abductor pollicis brevis (APB), first dorsal interosseus (FDI), flexor carpi radialis and extensor carpi radialis muscles. Changes of test MEP size following conditioning stimulation of the right median nerve (or of the index finger) at conditioning-test (C-T) intervals of 50, 200, 600 and 1000 ms were analysed. Peripheral stimulation significantly reduced test MEP size in the APB and FDI muscles of normal control and spasmodic torticollis patients. The inhibitory effect was larger upon median nerve stimulation and reached a maximum at the C-T interval of 200 ms. On the contrary, hand cramp patients showed a significant facilitation of test MEP size. This study suggests that MEP suppression following peripheral stimulation is defective in patients with focal hand dystonia. Central processing of sensory input is abnormal in dystonia and may contribute to increased motor cortical excitability.

Intracortical inhibitory circuits and sensory input: a study with transcranial magnetic stimulation in humans

We compared intracortical inhibition (ICI) following paired transcranial magnetic stimulation (TMS) (interstimulus interval, ISI: 3 ms) and the inhibition of motor evoked potentials (MEPs) to TMS induced by stimulation of the median nerve (ISI: 200 ms) in six normal subjects. MEPs evoked by focal TMS were recorded in the relaxed opponens pollicis muscle and the size of the conditioned responses was expressed as a percentage of the size of the non-conditioned responses. Maximal ICI, ranging from 4 to 40%, and inhibition after median nerve stimulation, ranging from 11 to 68%, were significantly correlated. The results suggest that both phenomena are possibly mediated by the same gamma aminobutyric acid-ergic (GABAergic) inhibitory circuits and that afferent inputs to the cortex may contribute to their physiological activation.

Abnormalities of motor cortical excitability are not correlated with clinical features in atypical parkinsonism

OBJECTIVE

To evaluate the specificity of motor cortical excitability changes in parkinsonian syndromes and their relevance to the pathophysiology of cardinal parkinsonian features.

METHODS

Paired transcranial magnetic stimulation (TMS) was used to assess cortico-cortical inhibition (CCI) and facilitation (CCF) in the opponens pollicis muscle of patients with atypical, non-L-dopa- (LD) responsive parkinsonism.

RESULTS

Compared with age-matched normal control subjects, CCI (interstimulus interval [ISI], 3 ms) was significantly reduced in 10 patients with predominantly parkinsonian multiple system atrophy (MSA-P) and in seven with vascular parkinsonism (VP), but not in four with predominantly cerebellar MSA. No significant change of CCF (ISI, 12 ms) was observed. No correlation was found between the amount of CCI and clinical status as evaluated with the Unified Parkinson's Disease Rating Scale (UPDRS). In 10 patients (5 MSA-P, 5 VP), CCI was significantly increased by LD acute administration without concurrent clinical changes.

CONCLUSIONS

Abnormalities of CCI are not peculiar to idiopathic Parkinson's disease and seem unlikely to underlie any specific parkinsonian feature, but rather possibly reflect a nonspecific imbalance of inhibitory and facilitatory motor cortical circuits.

Motor recovery following stroke: a transcranial magnetic stimulation study

OBJECTIVES

To verify the usefulness of early recording of motor evoked potentials (MEPs) in predicting motor outcome after stroke and to investigate the neural mechanisms underlying functional recovery following stroke.

METHODS

We performed a comparative analysis of the behaviour of motor responses evoked by transcranial magnetic stimulation (TMS) of the ipsilateral and contralateral motor cortex in the affected and unaffected thenar muscles of 21 consecutive patients with acute stroke.

RESULTS

According to the behaviour of MEPs in the affected muscles, patients could be divided into 3 groups: (a) 10 subjects with absent responses to TMS of both the damaged and undamaged hemisphere, whose motor recovery was poor and related to the size of MEPs on the normal side; (b) 5 subjects with larger MEPs upon TMS of the ipsilateral (undamaged) than of the contralateral (damaged) cortex, whose good recovery possibly resulted from the emergence of ipsilateral pathways; (c) 6 subjects with larger MEPs in the affected than in the unaffected muscles, whose good recovery was possibly subserved by alternative circuits taking over cortical deafferentation.

CONCLUSIONS

Early MEP recording in acute stroke provides useful information on the clinical prognosis and the different mechanisms of motor recovery.

Intracortical inhibition after paired transcranial magnetic stimulation depends on the current flow direction

OBJECTIVES

To assess whether cortico-cortical inhibition (CCI) induced by paired-pulse transcranial magnetic stimulation (TMS) is influenced by 'preferential' or 'non-preferential' activation of the motor cortex.

METHODS

Paired-pulse TMS (conditioning-test paradigm with interstimulus intervals of 2-5 ms) with a round coil centered over the vertex was performed in 10 normal subjects using opposite current flow directions. The amount of CCI in the opponens pollicis and first dorsal interosseus muscles was determined.

RESULTS

When a clockwise current was induced in the brain (side A of the coil uppermost) a 'preferential' activation of the left hemisphere (right hand muscles) was observed, but the suppression of the test response by the conditioning stimulus (i.e. the CCI) was significantly greater in the left hand muscles. The situation was reversed when an anticlockwise current (side B of the coil uppermost) was induced in the brain. These effects occurred independently of the interstimulus interval, or of the absolute conditioning stimulus strength.

CONCLUSIONS

CCI is more effective in the 'non-preferentially' stimulated hemisphere, and the neural elements generating the indirect I3 wave are more sensitive to intracortical inhibition than those generating the I1 wave.

Changes of intracortical inhibition during motor imagery in human subjects

Paired-pulse transcranial magnetic stimulation with a conditioning-test paradigm was used to assess changes of corticocortical inhibition and facilitation during mental simulation of sequential finger movements in normal subjects. The cortico-cortical inhibition (at interstimulus interval, ISI, of 3 ms) was significantly reduced in the relaxed opponens pollicis (OP) muscle during motor imagery, regardless of the absolute size of the test motor evoked potential. The amount of cortico-cortical inhibition was similar to that observed during a mild voluntary contraction of the OP. No change of cortico-cortical facilitation was observed at the ISI of 12 ms. The data support the hypothesis that similar neural structures, including the primary motor cortex, are activated during both mental simulation and actual execution of motor activities.

Comparison of intracortical inhibition and facilitation in distal and proximal arm muscles in humans

1. Cortico-cortical inhibition and facilitation induced by paired transcranial magnetic stimulation (TMS) of the human motor cortex were investigated in the distal muscle opponens pollicis (OP) and the proximal muscle biceps brachii (BB) of normal subjects. 2. The test response evoked by TMS (125 % of motor threshold, MTh) in the relaxed OP and BB muscles was inhibited by a conditioning TMS (80 % of MTh) at short interstimulus intervals (ISIs; 2-5 ms) and facilitated at longer ISIs (10-25 ms). The test response was significantly less inhibited at short ISIs and more facilitated at long ISIs in the BB than OP. 3. The MTh at rest was significantly lower for the OP than for the BB, indicating a greater excitability of OP cortical area. However, the above pattern of inhibition and facilitation was preserved both when the stimulus intensity was adjusted to evoke test responses of matched size in the two muscles and within an ample range of conditioning stimulus intensities. 4. The use of a circular coil or a focal figure-of-eight coil produced no qualitative differences in the pattern of inhibition and facilitation in either muscle. 5. The significant difference in MTh between muscles was lost during voluntary activation. In both muscles, pre-innervation abolished the cortico-cortical facilitation and reduced the cortico-cortical inhibition. However, the latter remained larger in the OP than BB muscle. 6. We suggest that the different potency of intracortical inhibitory and facilitatory circuits directed towards distal and proximal arm muscles is related to their diverse prevalent functions.