Search

Ammonium propionate is authorised as a liquid preparation of ≥ 19% ammonium propionate, ≤ 80% propionic acid and ≤ 30% water. The applicant requested for the renewal of the authorisation of ammonium propionate when used as a feed additive for all terrestrial animal species. The applicant has provided evidence that the additive in the market complies with the conditions of the authorisation. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) confirms that the use of ammonium propionate under the current authorised conditions of use is safe for the target species, the consumers and the environment. Concerning the user safety, the additive is corrosive to skin and eyes. Any exposure is considered a risk. There is no need for assessing the efficacy of the additive in the context of the renewal of the authorisation., (© 2024 European Food Safety Authority. EFSA Journal published by Wiley‐VCH GmbH on behalf of European Food Safety Authority.)

Platelets are central elements of hemostasis and also play a pivotal role in the pathogenesis of thrombosis in coronavirus disease 2019. This study was planned to investigate the effects of different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recombinant spike protein variants on platelet morphology and activation. Citrated whole blood collected from ostensibly healthy subjects was challenged with saline (control sample) and with 2 and 20 ng/mL final concentration of SARS-CoV-2 recombinant spike protein of Ancestral, Alpha, Delta, and Omicron variants. Platelet count was found to be decreased with all SARS-CoV-2 recombinant spike protein variants and concentrations tested, achieving the lowest values with 20 ng/mL Delta recombinant spike protein. The mean platelet volume increased in all samples irrespective of SARS-CoV-2 recombinant spike protein variants and concentrations tested, but especially using Delta and Alpha recombinant spike proteins. The values of both platelet function analyzer-200 collagen-adenosine diphosphate and collagen-epinephrine increased in all samples irrespective of SARS-CoV-2 recombinant spike protein variants and concentrations tested, and thus reflecting platelet exhaustion, and displaying again higher increases with Delta and Alpha recombinant spike proteins. Most samples where SARS-CoV-2 recombinant spike proteins were added were flagged as containing platelet clumps. Morphological analysis revealed the presence of a considerable number of activated platelets, platelet clumps, platelet-monocyte, and platelet-neutrophils aggregates, especially in samples spiked with Alpha and Delta recombinant spike proteins at 20 ng/mL. These results provide support to the evidence that SARS-CoV-2 is capable of activating platelets through its spike protein, though such effect varies depending on different spike protein variants., Competing Interests: None declared., (Thieme. All rights reserved.)

We report a t BuOK-promoted synthesis of 1,3-dihydro-2 H -pyrrol-2-one and 4-methylenepyrrolidin-2-one systems via Conia-ene like intramolecular cyclization. The method features extremely short reaction times (5 min) and mild reaction conditions (rt), enabling the trapping of a propargyl unit by an amide enolate. An intriguing anionic chain mechanism is at work, which can trigger the isomerization of an exo -alkene giving access to the otherwise elusive endo -product.

Objectives: There is limited information on the influence of collecting small amounts of blood on the quality of blood gas analysis. Therefore, the purpose of this study was to investigate the effects of different degrees of underfilling of syringes on test results of venous blood gas analysis., Methods: Venous blood was collected by venipuncture from 19 healthcare workers in three 1.0 mL syringes for blood gas analysis, by manually aspirating different volumes of blood (i.e., 1.0, 0.5 and 0.25 mL). Routine blood gas analysis was then immediately performed with GEM Premier 5,000. The results of the two underfilled syringes were compared with those of the reference syringe filled with appropriate blood volume., Results: The values of most assayed parameters did not differ significantly in the two underfilled syringes. Statistically significant variations were found for lactate, hematocrit and total hemoglobin, the values of which gradually increased as the fill volume diminished, as well as for sodium concentration, which decreased in both insufficiently filled blood gas syringes. The bias was clinically meaningful for lactate in syringe filled with 0.25 mL of blood, and for hematocrit, total hemoglobin and sodium in both syringes containing 0.5 and 0.25 mL of blood., Conclusions: Collection of smaller volumes of venous blood than the specified filling volume in blood gas syringes may have an effect on the quality of some test results, namely lactate, hematocrit, total hemoglobin and sodium. Specific indications must be given for standardizing the volume of blood to be collected within these syringes., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

This study investigated the biological effects on circulating monocytes after challenge with SARS-CoV-2 recombinant spike protein. Whole blood collected from seven ostensibly healthy healthcare workers was incubated for 15 min with 2 and 20 ng/mL final concentration of recombinant spike protein of Ancestral, Alpha, Delta, and Omicron variants. Samples were analyzed with Sysmex XN and DI-60 analyzers. Cellular complexity (i.e., the presence of granules, vacuoles and other cytoplasmic inclusions) increased in all samples challenged with the recombinant spike protein of the Ancestral, Alpha, and Delta variants, but not in those containing Omicron. The cellular content of nucleic acids was constantly decreased in most samples, achieving statistical significance in those containing 20 ng/mL of Alpha and Delta recombinant spike proteins. The heterogeneity of monocyte volumes significantly increased in all samples, achieving statistical significance in those containing 20 ng/mL of recombinant spike protein of the Ancestral, Alpha and Delta variants. The monocyte morphological abnormalities after spike protein challenge included dysmorphia, granulation, intense vacuolization, platelet phagocytosis, development of aberrant nuclei, and cytoplasmic extrusions. The SARS-CoV-2 spike protein triggers important monocyte morphological abnormalities, more evident in cells challenged with recombinant spike protein of the more clinically severe Alpha and Delta variants.

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of the feed additive consisting of Lactobacillus acidophilus CECT 4529 (tradename: Lactobacillus acidophilus D2/CSL) when used as a zootechnical additive for all poultry species and categories and all ornamental birds. The additive is authorised for use in laying hens, chickens for fattening, cats and dogs. With this application, the company requested a new authorisation for use in feed and water for drinking for all poultry species and categories and ornamental birds. The Panel concluded that Lactobacillus acidophilus D2/CSL is presumed safe for the target species, consumers and the environment. As in previous opinions, the Panel also concluded that it is considered an eye/skin irritant and a skin/respiratory sensitiser. Lactobacillus acidophilus D2/CSL when supplemented at 1 × 10 9 CFU/kg complete feed or 5 × 10 8 CFU/L water for drinking has the potential to be efficacious in to improving either laying or growing performance in all poultry species/categories and ornamental birds., (© 2022 Wiley‐VCH Verlag GmbH & Co. KgaA on behalf of the European Food Safety Authority.)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the assessment of Calsporin ® ( Bacillus velezensis DSM 15544) as a zootechnical additive for dairy cows and other dairy ruminants. The product under assessment is based on viable spores of Bacillus velezensis DSM 15544. B. velezensis is considered suitable for the qualified presumption of safety (QPS) approach to safety assessment. The identity of the active agent was established and compliance with the applicable qualifications confirmed. Therefore, B. velezensis DSM 15544 is presumed safe for the target species, consumers of products derived from animals fed the additive and the environment. Since no concerns are expected from the other components of the additive, Calsporin ® is also considered safe for the target species, consumers of products derived from animals fed the additive and the environment. The additive is not a dermal/eye irritant or a skin sensitiser but should be considered a respiratory sensitiser. The FEEDAP Panel is not in the position to conclude on the efficacy of Calsporin ® for dairy cows or other dairy ruminants based on the data provided., (© 2022 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Allura Red AC for small non-food-producing mammals and ornamental birds when used as an additive that add or restore colour in feedingstuffs. The use of Allura Red AC up to the proposed conditions of use of 500 mg/kg complete feed is considered safe for guinea pig, chinchilla, degu, hamster, gerbil and chipmunk. The following maximum safe levels (mg/kg complete feed) apply to the following species: ferrets 99, rabbits 123, canaries, budgerigars, mynah and toucans 45, lovebirds 51, cockatiels 79, cockatoos 115, amazons 145, parrots 147, yellow breast macaw 150, blue-throated macaw 173 and hyacinth macaw 214. The maximum safe level of Allura Red AC for other small non-food-producing mammal is 99 mg/kg feed and for other ornamental birds is 45 mg/kg feed. Inhalation exposure of Allura Red is regarded as hazardous. In the absence of data, the Panel cannot conclude on the potential of Allura Red to be a skin/eye irritant or a skin sensitiser. The FEEDAP Panel cannot conclude on the efficacy of the additive., (© 2021 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the assessment of the application for renewal of authorisation of all-rac-alpha-tocopheryl acetate (vitamin E) as a feed additive for all animal species. The applicant provided data demonstrating that the additive currently in the market complies with the conditions of authorisation. The FEEDAP Panel confirms that the use of all-rac-alpha-tocopheryl acetate under the current authorised conditions of use is safe for the target species, the consumers and the environment. No concern for user safety is expected from the use of the active substance; however, due to the lack of information, the FEEDAP Panel is not able to conclude on its skin sensitisation potential. To draw conclusions on the safety for the user of the final formulated additives, specific studies would be required. There is no need to assess the efficacy of all-rac-alpha-tocopheryl acetate in the context of the renewal of the authorisation., (© 2021 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.)

The accurate control of the crystal phase in III-V semiconductor nanowires (NWs) is an important milestone for device applications. Although cubic zinc-blende (ZB) GaAs is a well-established material in microelectronics, the controlled growth of hexagonal wurtzite (WZ) GaAs has thus far not been achieved successfully. Specifically, the prospect of growing defect-free and gold catalyst-free wurtzite GaAs would pave the way towards integration on silicon substrate and new device applications. In this article, we present a method to select and maintain the WZ crystal phase in self-assisted NWs by molecular beam epitaxy. By choosing a specific regime where the NW growth process is a self-regulated system, the main experimental parameter to select the ZB or WZ phase is the V/III flux ratio. Using an analytical growth model, we show that the V/III flux ratio can be finely tuned by changing the As flux, thus driving the system toward a stationary regime where the wetting angle of the Ga droplet can be maintained in the range of values allowing the formation of pure WZ phase. The analysis of the in situ reflection high energy electron diffraction evolution, combined with high-resolution scanning transmission electron microscopy (TEM), dark field TEM, and photoluminescence all confirm the control of an extended pure WZ segment, more than a micrometer long, obtained by molecular beam epitaxy growth of self- assisted GaAs NWs with a V/III flux ratio of 4.0. This successful controlled growth of WZ GaAs suggests potential benefits for electronics and opto-electronics applications.

The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS-COV-2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet-based precision extrusion deposition (db-PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home-grade printing equipment have similar performances compared to the industrial-grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post-processing phases essential to assure human safety in the production of 3D printed custom medical devices.

It is well known that the crystalline structure of the III-V nanowires (NWs) is mainly controlled by the wetting contact angle of the catalyst droplet which can be tuned by the III and V flux. In this work we present a method to control the wurtzite (WZ) or zinc-blende (ZB) structure in self-catalyzed GaAs NWs grown by molecular beam epitaxy, using in situ reflection high energy electron diffraction (RHEED) diagram analysis. Since the diffraction patterns of the ZB and WZ structures differ according to the azimuth [11̄0], it is possible to follow the evolution of the intensity of specific ZB and WZ diffraction spots during NW growth as a function of the growth parameters such as the Ga flux. By analyzing the evolution of the WZ and ZB spot intensities during NW growth with specific changes of the Ga flux, it is then possible to control the crystal structure of the NWs. ZB GaAs NWs with a controlled WZ segment have thus been realized. Using a semi-empirical model for the NW growth and our in situ RHEED measurements, the critical wetting angle of the Ga catalyst droplet for the structural transition is deduced., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this work we show that the incidence angle of group-III element fluxes plays a significant role in the diffusion-controlled growth of III-V nanowires (NWs) by molecular beam epitaxy (MBE). We present a thorough experimental study on the self-assisted growth of GaAs NWs by using a MBE reactor equipped with two Ga cells located at different incidence angles with respect to the surface normal of the substrate, so as to ascertain the impact of such a parameter on the NW growth kinetics. The as-obtained results show a dramatic influence of the Ga flux incidence angle on the NW length and diameter, as well as on the shape and size of the Ga droplets acting as catalysts. In order to interpret the results we developed a semi-empirical analytical model inspired by those already developed for MBE-grown Au-catalyzed GaAs NWs. Numerical simulations performed with the model allow us to reproduce thoroughly the experimental results (in terms of NW length and diameter and of droplet size and wetting angle), putting in evidence that under formally the same experimental conditions the incidence angle of the Ga flux is a key parameter which can drastically affect the growth kinetics of the NWs grown by MBE., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

With a band gap value of 1.7 eV, Al 0.2 Ga 0.8 As is one of the ideal III-V alloys for the development of nanowire-based Tandem Solar Cells on silicon. Nevertheless, growing self-catalysed AlGaAs nanowires on silicon by solid-source molecular beam epitaxy is a very difficult task due to the oxidation of Al adatoms by the SiO 2 layer present on the surface. Here we propose a nanowire structure including a p.i.n radial junction inside an Al 0.2 Ga 0.8 As shell grown on a p-GaAs core. The crystalline structure of such self-catalysed nanowires grown on an epi-ready Si(111) substrate (with a thin native SiO 2 layer) was investigated by transmission electronic microscopy and photoluminescence. I(V) measurements performed on single nanowires have shown a diode-like behaviour corresponding to the radial p.i.n junction inside the Al 0.2 Ga 0.8 As shell. Moreover, a current generation under the electron beam was evidenced over the entire radial junction along the nanowires by means of electron beam induced current (EBIC) microscopy. The same structure was reproduced on patterned substrates with a SiO 2 mask, producing an ordered hexagonal array. High and uniform yields from 83% to 87% of vertical nanowires were obtained on 0.9 × 0.9 cm 2 patterned areas. EBIC mapping performed on these nanowires confirmed the good electrical properties of the radial junction within the nanowires.

The coccidiostat Monimax ® (monensin sodium and nicarbazin) is considered safe for chickens for fattening and chickens reared for laying at the highest use level of 50 mg monensin and 50 mg nicarbazin/kg complete feed. This conclusion is extended to chickens reared for laying. For both active substances, the metabolic pathways in the chicken are similar to those in the turkey and rat. Nicarbazin, when ingested, is rapidly split in its two components dinitrocarbanilide (DNC) and 2-hydroxy-4,6-dimethylpyrimidine (HDP) which behave independently. Monimax ® does not represent a genotoxic risk. No safety concerns would arise from the nicarbazin impurities p -nitroaniline and methyl(4-nitrophenyl) carbamate. The lowest no observed effect level (NOEL) identified for monensin sodium in a developmental study in rabbits is 0.3 mg monensin sodium/kg body weight (bw) per day for maternal toxicity in rabbits. The lowest no observed adverse effect level (NOAEL) identified in a 52-week study in rat using DNC + HDP was 20 mg DNC + 8 mg HDP/kg bw per day based on the absence of microcrystals in urine and related microscopic renal observations. No significant interaction between monensin sodium and nicarbazin is expected from toxicological studies. The use of Monimax ® at the highest proposed dose will not pose a risk to persons consuming animal products from treated chickens for fattening. This conclusion is extended to chickens reared for laying. No withdrawal time is required for Monimax ® in chickens for fattening. Residue data comply with the established maximum residue limits (MRLs) for monensin and DNC. Based on the available data, the FEEDAP Panel cannot conclude on the safety of Monimax ® for the environment. Monimax ® has the potential to control coccidiosis in chickens for fattening at a minimum concentration of 40 mg monensin and 40 mg nicarbazin/kg complete feed., (© 2018 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.)

One obstacle for the development of nanowire (NW) solar cells is the challenge to assess and control their nanoscale electrical properties. In this work a top-cell made of p-n GaAs core/shell NWs grown on a Si(111) substrate by Molecular Beam Epitaxy (MBE) is investigated by high resolution charge collection microscopy. Electron Beam Induced Current (EBIC) analyses of single NWs have validated the formation of a homogeneous radial p-n junction over the entire length of the NWs. The radial geometry leads to an increase of the junction area by 38 times with respect to the NW footprint. The interface between the NWs and the Si(111) substrate does not show any electrical loss, which would have led to a decrease of the EBIC signal. Single NW I-V characteristics present a diodic behavior. A model of the radial junction single NW is proposed and the electrical parameters are estimated by numerical fitting of the I-Vs and of the EBIC map. Solar cells based on NW arrays were fabricated and analyzed by EBIC microscopy, which evidenced the presence of a Schottky barrier at the NW/ITO top contact. Improvement of the top contact quality is achieved by thermal annealing at 400 °C, which strongly reduces the parasitic Schottky barrier.

Me-Hg and PCB153 are known neurotoxic contaminants which tend to accumulate in food, particularly in fish. Aim of this study was to perform asynchronous and combined exposure to Me-Hg and PCB153 in a neuronal rat cell line (PC12) to better characterise the antagonism observed at some combination concentrations. PC12 cells were treated with three concentrations of Me-Hg (0.1-0.5-1.0 microM) and PCB153 at one concentration (175 microM) in single and combined asynchronous exposures, using viability (MTT assay) as end-point. At all concentrations used, a statistically significant antagonistic effect was observed when Me-Hg preceded PCB153 exposure, while effect was additive when PCB153 preceded Me-Hg exposure. The antagonism is particularly evident at low concentrations of Me-Hg (0.1 microM). In conclusion, combined asynchronous exposure showed that whereas Me-Hg can modulate PCB153 toxicity, the opposite seems not to be true. Therefore, the use of asynchronous exposure could be a promising approach to study the mechanisms of toxicity of binary mixtures.

The study of interactions for those substances which tend to accumulate in food and affect the nervous system appears to be a fundamental point to characterize the combined exposure in vitro. In this study we included two food contaminants which are known neurotoxicants: methyl-mercury (Me-Hg) and the ortho-substituted PCB 153. PC12 cells were treated with Me-Hg (range 1e-7, 2e-6 M) and PCB153 (range 1e-5, 4e-4 M) in single and combined synchronous experiments and a mathematical model was set up according to the Loewe additivity criterion to evaluate the level of interaction between toxicants, using viability as end-point. At some concentrations (Me-Hg 5e-7 M and PCB153 1e-4 and 2e-4 M; Me-Hg 1e-6M and PCB153 5e-5 M; Me-Hg 1e-7 M and PCB153 4e-4 M), a statistically significant antagonist effect was observed. No interaction was observed for other combinations. The analysis of other toxicological parameters known to be modified in single exposure experiments (TBARS and intra-cellular dopamine) confirmed the viability results. The results of our work represent a starting point to generate novel information on the interactions between PCB153 and Me-Hg in vitro, as well as a new relevant experimental and mathematical approach useful to investigate the effects of different toxicant mixtures.

Styrene-7,8-oxide (SO) is the main metabolite of styrene, a neurotoxic volatile organic compound used industrially. Here we report the novel observation that several markers of oxidative stress were affected in SK-N-MC cells exposed for 16 h to concentrations of SO that induce apoptotic cell death. The production of Thiobarbituric Acid Reactive Substances (TBARS), rose from 69.1 +/- 15.7 nmol/g protein (control) to 119.3 +/- 39.2 and 102.0 +/- 17.3 nmol/g protein after exposure to 0.3 and 1 mM SO, respectively. Carbonyl group levels were significantly enhanced by SO at both concentrations. The lower dose also decreased sulphydryl groups. SO caused a marked oxidative DNA damage, as shown by a fivefold increase in 8-hydroxy-2(')-deoxyguanosine (8-OHdG). In addition, SO exposure resulted in alterations of scavenging abilities, given the reduction of both glutathione (GSH) and glutathione-S-transferase (GST) activity. Induction of expression of the oxidative stress response gene heme-oxygenase-1 (HO-1) and an increased HO-1 activity were also observed. These data provide compelling evidence that oxidative stress significantly contributes to SO toxicity in neuronal cells.

Styrene 7,8-oxide (SO) is the main metabolite of styrene, a neurotoxic compound used industrially. Neurons exposed to SO undergo apoptosis with characteristic features including chromatin rearrangements and caspase activation. We report that the execution phase of apoptosis induced by SO (0.3 mM) in SK-N-MC neurons is triggered by translocation of apoptogenic factors (e.g., cytochrome c) into the cytosol. In addition, mitochondria exhibit lower Ca2+ capacity and loss of mitochondrial membrane potential (DeltaPsi). Lipid peroxidation, measured as thiobarbituric acid reactive substances (TBARS), is increased after 12 h. Pre-treatment with the antioxidant MnTBAP (100 microM) prevents the decrease of Ca2+ capacity, cytochrome c release, activation of caspases, exposure of phosphatidylserine and cell death. Hence, the neurotoxic effects of SO are related to mitochondrial damage and oxidative stress.

The BMD approach has been used to compare the cell viability (MTT assay) of different rat (C6 and PC12, glial and neuronal, respectively) and human cell lines (D384 and SK-N-MC, glial and neuronal, respectively) after 24-h exposure to the following neurotoxic substances: Manganese Chloride (MnCl2), Methyl-mercury (Me-Hg) and the enantiomers of Styrene Oxide (SO). For all rat and human cell lines, the potency of the examined compounds was: MnCl2 < S-SO < R-SO < Me-Hg. A preliminary comparison with in vivo toxicity data for these substances gave rise to consistent results. Whereas a reasonable agreement between in vitro and in vivo data has been found for Mn and styrene oxide, a wide scatter of LOAEL has been reported for Me-Hg and these appear to be either much higher or lower than the BMD for the MTT assay we observed in vitro.

This study was aimed at evaluating whether controlled short-term exposure to ozone (O(3)) induces changes in biomarkers of lung inflammation and oxidative stress in exhaled breath condensate (EBC) and blood of healthy subjects. Twenty-two volunteers were exposed to 0.1 ppm of O(3) for 2 h while performing moderate intermittent exercise. EBC and blood were collected before, immediately after and 18 h after exposure. Changes in biomarkers were measured both in EBC and blood, without significant alterations of lung function tests. Changes in EBC, but not in blood, were mainly accounted for by a subgroup of 'susceptible' individuals bearing the wild genotype for NAD(P)H:quinone oxidoreductase (NQO1) and the null genotype for glutathione-S-transferase M1 (GSTM1). Thus, a single 2-h exposure to 0.1 ppm of O(3) induces changes in biomarkers of inflammation and oxidative stress. Polymorphic NQO1 and GSTM1 act as modifier of the lung response to O(3).

The role of the genetic polymorphism of NAD(P)H:quinone oxidoreductase (NQO1) and glutathione-S-transferase micro-1 (GSTM1) in the responsiveness to O(3)-induced acute effects was investigated in 24 healthy nonsmokers performing 2-h bike rides at ambient O(3) varying from 32 to 103 ppb. Before and after rides, each subject performed spirometric tests and provided a blood sample for the measurement of the Clara cell protein CC16. NQO1 and GSTM1 polymorphisms were characterized by polymerase chain reaction- based methods. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) adduct was also measured in DNA of peripheral leukocytes. Rides at O(3) > 80 ppb resulted in significant decrements of pulmonary function tests and increased levels of serum CC16, consistent with mild impairment in respiratory function and increased lung epithelial permeability, respectively. Whereas NQO1wt and GSTM1null subjects showed both functional changes and increased serum CC16 after acute O(3) exposure, people with other haplotypes showed a rise in serum CC16 but no changes in lung function tests. In NQO1wt and GSTM1null subjects, partial correlation analysis showed that functional decrements and increased serum CC16 are closely associated with each other and with O(3) levels, whereas no such relationships were found among subjects bearing other haplotypes. An increased reaction rate between O(3) and hydroquinones would be consistent with the greater increase in 8-OHdG after O(3) exposure in this "susceptible" group.

Dopamine (DA) is synthesized in amacrine cells and released upon membrane depolarization in a calcium-dependent way. Thus, it is recognized to function as a major neurotransmitter or modulator in vertebrate retina. Owing to DA modulating activity on cone-horizontal cells transmission, depletion or dysfunction of amacrine cells could interfere with chromatic processing, accounting for the acquired dyschromatopsia described among styrene-exposed workers. The present study has been designed to test the hypothesis that amacrine cells represent a vulnerable target of styrene in subchronically exposed rats. Ten female Sprague-Dawley rats were exposed to 300 ppm styrene 6 h/day, 5 days/week, for 12 weeks; ten rats exposed to fresh air served as a control group. Whole mounted retinas were used for the morphometry of tyrosine hydroxylase (TH) immunoreactive cells (IR). DA content and TH activity were measured by HPLC and electrochemical detection and glutathione (GSH) was measured by HPLC tandem mass spectrometry (LC-MS/MS). In treated rats, morphometric analysis showed a loss of TH-IR amacrine cells (6.2/mm2 vs. 8.7/mm2 recorded in controls, p = 0.002), without any peripheral-central variation in cell loss. DA content was also lower in exposed, as compared to control animals (208.64 vs. 267.98 microg/g w.w., p = 0.004). The activity of TH in the whole retina was similar in styrene-exposed and control rats when expressed as a function of the wet weight, whereas it was much higher in styrene-exposed rats (+64%) when expressed as a function of the number of TH-IR amacrine cells (p < 0.001). Finally, retinal GSH was reduced by 30% in exposed as compared to control rats (p = 0.01). In summary, retinal TH-IR cells were sensitive to styrene exposure, which seems to cause both structural and functional changes, represented by cell loss and DA depletion, respectively. These findings confirm the vulnerability of dopaminergic systems to styrene toxicity, providing some insights on the possible mechanism of loss in chromatic discrimination recorded among workers occupationally-exposed to styrene.

PC12 (undifferentiated and differentiated) and C6 cells have been used to investigate kinetics, morphological and functional endpoints following exposure to MnCl(2) and manganic transferrin (Mn-Tf). [Mn](i) in undifferentiated (non-differentiated cells) exposed to both free (MnCl(2)) and bound Mn (Mn-Tf), was three- to fivefold lower as compared to differentiated (differentiated) PC12 cells and higher by one order of magnitude as compared to glial C6 cells. Exposure to both MnCl(2) and Mn-Tf was followed by time- and dose-dependent morphological changes characteristic of apoptosis, which was never observed in Mn-exposed C6 glial cells. Results from cell viability assays were consistent with apoptotic response rates quantified by cell count. Threshold concentrations for undifferentiated and differentiated PC12 cells were 10(-6) and 10(-5)m, respectively. Thus, despite their greater ability to accumulate Mn, differentiated PC12 cells are less sensitive to Mn-induced apoptosis. This model might be relevant to neuronal degeneration induced by Mn occurring in the developing brain and possibly in clinical manganism. Such critical doses at the cellular level seem to be consistent with Mn levels (5x10(-6)m) recorded in the basal ganglia of monkeys chronically exposed to Mn and developing clinical signs of manganism.

Aim: A cross-sectional investigation was carried out to assess possible relations between styrene-induced changes in three peripheral markers of catecholaminergic dysfunction and self-reported symptoms of neurotoxicity., Subjects: Male workers (n = 46) aged 14-60 (mean 29.5) years who had been exposed to styrene for an average of 6 (0.2-29) years were recruited in glassfiber reinforced plastics plants. A control group of 30 blue-collar workers aged 22-52 (mean 35) years and with no history of exposure to chemicals was recruited from local industries. Styrene exposure ranged from 5 to 120 ppm (8 h-TWA), the median level being relatively low (25 ppm, 8 h-TWA). Styrene metabolites, mandelic and phenylglycoxylic acids (MAPGA) in the "next morning" urine spot samples ranged from 32.0 to 931.1 mg/g creatinine (median 186.5)., Methods: Platelet monoamine oxidases B (MAO B) and dopamine beta-hydroxylase (DBH) activities were assessed using methods based on HPLC and electrochemical detection. Plasma prolactin (PRL) was measured by a commercially available immunoassay. Questionnaire 16 (Q16) was used to survey self-reported symptoms., Results: Although there was no difference in DBH activity between exposed workers and controls, the most highly exposed workers had significantly lower activity than control subjects. A tendency to lower platelet MAO B activity in exposed than in control subjects was observed. The prevalence of plasma DBH and platelet MAO B values below the lower reference limit was similar in the two groups. PRL values exceeding the upper reference limit were higher (14/46 vs 2/30) among styrene-exposed workers, who also exhibited significantly higher median levels (10.0 vs 5.7 micrograms/l) than control subjects. Although the number of reported symptoms was similar among exposed and control subjects, in the exposed group it was positively associated with urinary MAPGA (Rho = 0.30, P = 0.04). Of the three peripheral markers of catecholaminergic dysfunction, plasma DBH was the only parameter negatively related to both urinary MAPGA (F = 9.56, P = 0.003) and the number of reported symptoms (Rho = 0.23, P = 0.05)., Conclusions: Plasma PRL appears to be a sensitive marker of styrene-induced tubero-infundibular dopaminergic dysfunction in male subjects. DBH in plasma and MAO B in platelets seem to be less suitable markers for biomonitoring effect at the individual level, although DBH was related to the number of reported symptoms and to internal dose. Further studies on a larger and more exposed population are necessary to clarify the significance of these markers for health and their predictive value with regard to both subjective disturbances and concurrently administered performance tests.

The present study was aimed at assessing the role of Mn valency state in Mn-induced changes in DA metabolism by PC12 cells. Mn(ll)Cl2, Mn(lll)Acetate, and Mn(IV)O2 were used for these experiments. PC12 cells were incubated for 3, 24 and 72 hours to Mn nominal concentrations ranging from 10-8 to 10(-4) M in 24-well plates containing 2 x 10(5) cells/well. Supernatants and cellular materials were then separated and immediately processed for the analysis of dopamine (DA), and its metabolite 3,4-di-hydroxy-phenylacetic acid (DOPAC). Lactate dehydrogenase (LDH) activity and MTT cleavage were measured as indices of cell death. In parallel experiments, Mn-containing medium (10(-5) M) was removed and cells incubated for further periods with Mn-free medium to evaluate the reversibility of observed changes. At the end of the experimental periods, none of Mn-exposed cultures showed appreciable reduction in cell viability as compared to their respective controls. After exposure to Mn(II) and Mn(III), irreversible and dose-dependent decreases in the medium but not in intra-cellular DA were apparent. Indeed, 10(-4) M Mn(II) caused the disappearance of DA and DOPAC from the medium. The same effect was caused by 10(-5) M Mn(III), the dose-effect relationship being shifted towards lower dose levels. Mn(IV) induced a parallel and dose-dependent decrease of DA and DOPAC concentrations in both intra- and extra-cellular compartments. Such an effect was reversible after removal of Mn from the medium. Multiple interferences on DA metabolism are caused by Mn. Mn(II) and Mn(III) seem to block DA secretion without affecting DA turnover rate. Mn(IV) seems to cause DA depletion and aspecific (secondary) changes in secretion rates. Further studies are necessary to understand the mechanisms underlying the differential effects of various Mn compounds on DA metabolism.

Monoamine oxidase B (MAO-B) activity in platelets, serum dopamine-beta-hydroxylase (DBH) activity, and serum prolactin (PRL) were measured during a cross-sectional investigation in workers occupationally exposed to styrene. The study group consisted of 53 workers (33 men and 20 women) employed for 9.3 years on average (range 1-22) in reinforced plastics plants. Sixty industrial workers with no known exposure to chemicals and comparable as to age, sex and confounding variables were recruited as controls. The activities of MAO-B in platelet-rich plasma and of DBH in serum from exposed and control subjects were measured within the same run, using methods based on the liquid-chromatographic determination of the reaction products. Serum PRL was determined by both EIA and RIA. Blood samples had been collected between 8:00 and 9:00 a.m. A lower DBH activity was found in exposed as compared to control workers (GM: 7.25 U/ml serum vs. 10.11 U/ml serum; p < 0.01), whereas MAO-B activity was significantly lower in a heavily exposed subgroup (10.1 vs. 13.8 U/10(7) platelets; p = 0.05), but not in the whole sample (p = 0.07). Serum PRL was higher both in male (GM: 8.90 ng/ml vs. 6.05 ng/ml; p < 0.01) and female (GM: 12.6 ng/ml vs. 9.33 ng/ml; p < 0.05) styrene-exposed workers as compared to their respective controls. Dose-response relationships were found for abnormally low DBH and abnormally high PRL values, with a threshold occurring at metabolite levels corresponding to 8h-TWA styrene concentrations in air around 25 ppm. In summary, this study shows that long-term exposure to relatively low levels of styrene can affect DBH activity and basal serum PRL. Owing to its sensitivity, PRL is a useful biomarker to show impairments of dopaminergic control on pituitary secretion. Since DBH is expression of catecholamine secretion, its decreased activity could represent an indirect index of altered turnover rate of the physiological substrate (i.e.dopamine) at the neuronal level. However, a direct interference by styrene metabolites on enzyme activity cannot be ruled out. Platelet MAO-B activity seems to be less sensitive to styrene exposure.

Within the framework of an European Commission-funded project, groups of industrial workers exposed to heavy metals (cadmium, mercury and lead) or solvents were studied together with corresponding control groups. Eighty-one measurements were carried out on urine and serum samples and the scientific results together with individual questionnaire information were entered into a central database. Data obtained was assessed centrally and individually in subsidiary studies. The measurable contributions were assessed either singly or in combination, of smoking, gender, metal exposure and site, to nephrotoxicity. The potential value of each test as an indicator of nephrotoxicity was then assessed on the basis of sensitivity and specificity. A number of new tests including prostaglandins and for extracellular matrix components were investigated as well as established tests for renal damage and dysfunction. The data obtained from this comprehensive study emphasises the value of noninvasive biomarkers for the early detection of nephrotoxicity due to environmental toxins. The urinary profile varied with the type of environmental/occupational toxin. By careful selection of a small panel of markers they can be used to indicate the presence of renal damage, the principal region affected, and to monitor the progress of disease and damage. Biomarkers were also used to confirm and tentatively establish safe exposure levels to nephrotoxins.

To evaluate whether or not occupational exposure to manganese (Mn) affects basal levels of serum prolactin (PRL), a cross-sectional study was carried out in 31 occupationally-exposed workers, aged 39.2 years (DS 7.9) exposed to manganese (Mn) dusts for 14.5 years (range: 5 to 29 years) in a ferroalloy producing plant. Thirty-four industrial workers not exposed to neurotoxic chemicals and of comparable age composed the control group. Airborne Mn concentrations in dusts of the furnace area ranged 210 to 980 micrograms/m3, which is below the current American Conference of Governmental Industrial Hygienists (ACGIH)-recommended threshold limit value-time weighted average (TLV-TWA) of 1 mg/m3. Manganese concentrations in blood Mn (MnB) and in urine (MnU) were significantly higher in Mn-exposed workers as compared to control workers. The Mn-exposed workers showed significantly higher serum prolactin (PRL) levels with the geometric mean (GM) being 9.77 ng/ml with a geometric standard deviation (GSD) of 1.69 as compared to controls (GM 4.65 ng/ml, GSD 1.78, p < 0.001). Serum PRL was negatively related to age and positively correlated with both MnB and MnU. Dose-effect relationships were still significant in partial correlation analysis after control for age. The prevalence of abnormally high PRL values was consistent with a dose-response relationship. The observed increase in serum PRL among Mn-exposed workers suggests an impairment of tonic inhibition by tubero-infundibular dopaminergic neurons. The correlation between PRL and both MnB and MnU in samples collected at least 48 h from the last exposure suggests that such indices provide an estimation of the target dose.

In a preliminary study of 11 men randomly selected in a ferro-alloy plant and of 15 control subjects, platelet monoamine oxidase (MAO) and serum dopamine beta-hydroxylase (DBH) activities were measured. A tendency towards lower MAO-B activity in the exposed workers as compared to control subjects (t = 1.95; P = 0.06) was found whereas DBH activity was similar. In the exposed group, a dose-effect relationship was noted between a manganese (Mn) cumulative exposure index (CEI) and DBH activity (R2 = 0.40, P < 0.05). Since DBH is an expression of catecholamine release, the relative increase in such activity could be envisaged as a compensatory mechanism to a reduced turnover rate as reflected by MAO-B activity. Owing to the limited sample size, these findings should be confirmed by further epidemiological and experimental studies.

The genotoxic activities associated with airborne particulate matter collected in Parma (northern Italy) have been determined. The airborne particle extracts were tested for mutagenicity using Salmonella frameshift (TA98) and base-substitution (TA100) tester strains with and without S9 microsomal activation and Saccharomyces cerevisiae strain D7 in order to determine the frequency of mitotic gene conversion and ilv1-92 mutant reversion in cells harvested at stationary and logarithmic growth phase. The relationship between mitochondrial DNA mutations and ageing, degenerative diseases and cancer prompted us to take into account the mitochondrial informational target, i.e., the respiratory-deficient (RD) mutants. The results obtained show a variability in the response for the different test systems during different months. The Salmonella mutagenicity trend was directly correlated with carbon monoxide, nitrogen oxides (NOx) and Pb concentration in airborne particulates and inversely correlated with temperature, whereas the mitochondrial genotoxic effect was higher during spring and late summer. These data suggest that the genotoxic risk assessment is a time-dependent value strictly correlated with the evaluation system being tested.

During the National Research Council (CNR) program called Atherosclerosis-Risk Factors 2 (ATS-RF2) a random sample of 1903 subjects (50.1% male) aged 20-59 years was examined in the general population of Mirano-Venice. Mean values of serum total cholesterol and triglycerides, body mass index, as well as systolic and diastolic blood pressure were assessed. On the whole these turned out to be higher in men and increased with age. The continuously distributed variables showed an approximately normal distribution and a close correlation. Comparing our results with those obtained by other Italian units co-operating in the same CNR program, different levels of serum total cholesterol and systolic blood pressure were observed. The overall risk factor pattern in northern Italian regions is closer to that reported in the literature for central European countries than to that of southern Italian regions. These findings might explain why mortality due to ischaemic heart disease is higher in northern Italy and becomes progressively smaller in central and southern Italy.