Cumulative incidence of cardiovascular events under tamoxifen and letrozole alone and in sequence: a report from the BIG 1-98 trial.

BACKGROUND: Compared to tamoxifen, adjuvant treatment with aromatase inhibitors improves disease outcomes of postmenopausal women with hormone receptor-positive early breast cancer. In the international, randomized, double-blind BIG 1-98 trial, 8010 women were randomized to receive tamoxifen, letrozole, or sequential use of the agents for 5 years. With a focus on switching between agents, we investigated cardiovascular events over the entire 5-year treatment period. METHODS: Of the 6182 patients enrolled, 6144 started trial treatment and were included in this analysis. Adverse events occurring during study treatment until 30 days after cessation were considered. Eight cardiovascular event types were defined. Cumulative incidence of events were estimated using the Kaplan-Meier method, without consideration for competing events. Multivariable Cox models estimated hazard ratios (HR) with 95% confidence intervals (CI) for pairwise comparisons of treatment arms. RESULTS: While on study treatment, 6.5% of patients (n = 397) had any cardiac events reported; for 2.4%, the event was grades 3-5, of which 11 (0.2%) were grade 5. Letrozole monotherapy was associated with higher risk of grade 1-5 ischemic heart disease (HR = 1.81; 95% CI, 1.06-3.08) compared with tamoxifen monotherapy. Patients assigned sequential tamoxifen →letrozole (HR = 1.59; 95% CI, 0.92-2.74) or sequential letrozole → tamoxifen (HR = 1.20; 95% CI, 0.68-2.14) showed a lesser degree of risk elevation. Patients assigned to tamoxifen-containing regimens had significantly higher risk of grade 1-5 thromboembolic events (tamoxifen monotherapy HR = 2.10; 95% CI, 1.42-3.12; tamoxifen → letrozole HR = 1.96; 95% CI, 1.32-2.92; letrozole → tamoxifen HR = 1.56; 95% CI 1.03-2.35) as compared with patients assigned letrozole alone. CONCLUSION: When initiating or switching between adjuvant endocrine treatments in postmenopausal patients, age and medical history, with special attention to prior cardiovascular events, should be balanced with expected benefit of the treatment.

TiO2 nanoparticles in a biosolid-amended soil and their implication in soil nutrients, microorganisms and Pisum sativum nutrition.

The wide use of nanoparticles (NPs), gives concern about their possible negative implications in the environment and living organisms. In particular, titanium dioxide (TiO2) NPs are accumulated in biosolids (Bs) coming from wastewater treatment plants, which in turn are used as farm soil amendments and are becoming an important way of NPs entrance in the terrestrial ecosystems. In this study, to simulate a low and cumulative load of TiO2 NPs, 80 and 800 mg TiO2per Kg of soil were spiked in the Bs prior to its addition to soil. The effects of different crystal phases of TiO2 NPs (pure anatase and pure rutile or their mixture) and their non-coated bulk counterparts (larger particles) on the availability of mineral nutrients and on the status of the bacterial communities together with the nutritional status of Pisum sativum L. plants were evaluated. Results showed the reduction, to different extents, on the availability of important soil mineral nutrients (e.g. Mn 65%, Fe 20%, P 27%, averagely), in some cases size- (e.g. P) and dose-dependent. Bacterial biodiversity was also affected by the presence of high TiO2 dose in soil. The mineral nutrition of pea plants was also altered, showing the main reduction in Mn (80% in the roots and 50% in the shoots), K, Zn, P (respectively, 80, 40, and 35% in the roots), and an increase of N in the shoots, with possible consequences on the quality of the crop. The present study gives new integrated data on the effects of TiO2 NPs in the soil-plant system, on the soil health and on the nutritional quality of crops, rising new implications for future policies and human health.

The Moss Leptodictyum riparium Counteracts Severe Cadmium Stress by Activation of Glutathione Transferase and Phytochelatin Synthase, but Slightly by Phytochelatins.

In the present work, we investigated the response to Cd in Leptodictyum riparium, a cosmopolitan moss (Bryophyta) that can accumulate higher amounts of metals than other plants, even angiosperms, with absence or slight apparent damage. High-performance liquid chromatography followed by electrospray ionization tandem mass spectrometry of extracts from L. riparium gametophytes, exposed to 0, 36 and 360 µM Cd for 7 days, revealed the presence of γ-glutamylcysteine (γ-EC), reduced glutathione (GSH), and traces of phytochelatins. The increase in Cd concentrations progressively augmented reactive oxygen species levels, with activation of both antioxidant (catalase and superoxide dismutase) and detoxifying (glutathione-S-transferase) enzymes. After Cd treatment, cytosolic and vacuolar localization of thiol peptides was performed by means of the fluorescent dye monochlorobimane and subsequent observation with confocal laser scanning microscopy. The cytosolic fluorescence observed with the highest Cd concentrations was also consistent with the formation of γ-EC-bimane in the cytosol, possibly catalyzed by the peptidase activity of the L. riparium phytochelatin synthase. On the whole, activation of phytochelatin synthase and glutathione-S-transferase, but minimally phytochelatin synthesis, play a role to counteract Cd toxicity in L. riparium, in this manner minimizing the cellular damage caused by the metal. This study strengthens previous investigations on the L. riparium ability to efficiently hinder metal pollution, hinting at a potential use for biomonitoring and phytoremediation purposes.

Cadmium uptake, localization and stress-induced morphogenic response in the fern Pteris vittata.

Cadmium uptake, tissue localization and structural changes induced at cellular level are essential to understand Cd tolerance in plants. In this study we have exposed plants of Pteris vittata to different concentrations of CdCl2 (0, 30, 60, 100 µM) to evaluate the tolerance of the fern to cadmium. Cadmium content determination and its histochemical localization showed that P. vittata not only takes up, but also transports and accumulates cadmium in the aboveground tissues, delocalizing it mainly in the less bioactive tissues of the frond, the trichomes and the scales. Cadmium tolerance in P. vittata was strictly related to morphogenic response induced by the metal itself in the root system. Adaptive response regarded changes of the root apex size, the developmental pattern of root hairs, the differentiation of xylem elements and endodermal suberin lamellae. All the considered parameters suggest that, in our experimental conditions, 60 µM of Cd may represent the highest concentration that P. vittata can tolerate; indeed this Cd level even improves the absorbance features of the root and allows good transport and accumulation of the metal in the fronds. The results of this study can provide useful information for phytoremediation strategies of soils contaminated by Cd, exploiting the established ability of P. vittata to transport, delocalize in the aboveground biomass and accumulate polluting metals.

Isolated tumor cells in sentinel lymph nodes of invasive breast cancer: cell displacement or metastasis?

The goal of this study was to determine whether the presence of isolated tumoral cells (ITCs) in sentinel lymph nodes (SLNs) after core needle biopsy (CNB) is related to the time interval between CNB and surgery and to histopathologic features of invasive breast cancer. Data from 633 consecutive patients with no micrometastasis or metastasis on both frozen sections and definitive pathologic examination of SLNs were retrieved from a prospective data base. No association was found between ITCs and the time interval between CNB and SLNB. The association was significant with tumor size, the tumor lymphovascular invasion (LVI) and the histologic type of the tumor. This study adds supplementary data to the association between tumoral LVI and ITCs in SLNs, The time interval between CNB procedure and SLNB was not related to affect presence of ITCs, which might not suggest the iatrogenic origin of these cells.

Titanium dioxide nanoparticles enhance the detrimental effect of polystyrene nanoplastics on cell and plant physiology of Vicia lens (L.) Coss. & Germ. seedlings.

Polystyrene nanoplastics and titanium dioxide nanoparticles are widely spread in all environments, often coexisting within identical frameworks. Both these contaminants can induce negative effects on cell and plant physiology, giving concerns on their possible interaction which could increase each other's harmful effects on plants. Despite the urgency of this issue, there is very little literature addressing it. To evaluate the potential risk of this co-contamination, lentil seeds were treated for five days with polystyrene nanoplastics and titanium dioxide nanoparticles (anatase crystalline form), alone and in co-presence. Cytological analyses, and histochemical and biochemical evaluation of oxidative stress were carried out on isolated shoots and roots. TEM analysis seemed to indicate the absence of physical/chemical interactions between the two nanomaterials. Seedlings under cotreatment showed the greatest cytotoxic and genotoxic effects and high levels of oxidative stress markers associated with growth inhibition. Even if biochemical data did not evidence significant differences between materials treated with polystyrene nanoplastics alone or in co-presence with titanium dioxide nanoparticles, histochemical analysis highlighted a different pattern of oxidative markers, suggesting a synergistic effect by the two nanomaterials. In accordance, the fluorescence signal linked to nanoplastics in root and shoot was higher under cotreatment, perhaps due to the well-known ability of titanium dioxide nanoparticles to induce root tissue damage, in this way facilitating the uptake and translocation of polystyrene nanoplastics into the plant body. In the antioxidant machinery, peroxidase activity showed a significant increase in treated roots, in particular under cotreatment, probably more associated with stress-induced lignin synthesis than with hydrogen peroxide detoxification. Present results clearly indicate the worsening by metal nanoparticles of the negative effects of nanoplastics on plants, underlining the importance of research considering the impact of cotreatments with different nanomaterials, which may better reflect the complex environmental conditions.

Concordance between core needle biopsy and surgical excision specimens for tumour hormone receptor profiling according to the 2011 St. Gallen Classification, in clinical practice.

To focus on and compare the tumor hormone receptor profiles on core needle biopsy (CNB) and subsequent surgical excision specimens in a large clinical series of invasive breast carcinoma patients, with regard to guidelines proposed at the St. Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2011. A total of 993 consecutive patients who had hormone receptors (HR) assays performed on both CNB and subsequent surgical excision specimens of invasive carcinomas were included (1,110 tumors). Concordant tumor HR profiles between CNB and surgical excision specimens were noted in 1,085 of 1,110 tumors (97.75%). Among 138 tumors considered negative on CNB (both HR assays <1%), 10 cases (7.2%) displayed an HR profile positive on surgical excision specimen. Discrepancies between CNBs and surgical excision specimens are very seldom noted. HR assay evaluation on surgical excision specimens should only be considered in patients when both HR assays are negative on CNBs.

Do changes in Lactuca sativa metabolic performance, induced by mycorrhizal symbionts and leaf UV-B irradiation, play a role towards tolerance to a polyphagous insect pest?

The increased ultraviolet radiation (UV) due to the altered stratospheric ozone leads to multiple plant physiological and biochemical adaptations, likely affecting their interaction with other organisms, such as pests and pathogens. Arbuscular mycorrhizal fungi (AMF) and UV-B treatment can be used as eco-friendly techniques to protect crops from pests by activating plant mechanisms of resistance. In this study, we investigated plant (Lactuca sativa) response to UV-B exposure and Funneliformis mosseae (IMA1) inoculation as well as the role of a major insect pest, Spodoptera littoralis. Lettuce plants exposed to UV-B were heavier and taller than non-irradiated ones. A considerable enrichment in phenolic, flavonoid, anthocyanin, and carotenoid contents and antioxidant capacity, along with redder and more homogenous leaf color, were also observed in UV-B-treated but not in AMF-inoculated plants. Biometric and biochemical data did not differ between AMF and non-AMF plants. AMF-inoculated plants showed hyphae, arbuscules, vesicles, and spores in their roots. AMF colonization levels were not affected by UV-B irradiation. No changes in S. littoralis-feeding behavior towards treated and untreated plants were observed, suggesting the ability of this generalist herbivore to overcome the plant chemical defenses boosted by UV-B exposure. The results of this multi-factorial study shed light on how polyphagous insect pests can cope with multiple plant physiological and biochemical adaptations following biotic and abiotic preconditioning.

Preventive therapy for breast cancer: a consensus statement.

In March, 2010, a group of breast cancer experts met to develop a consensus statement on breast cancer prevention, with a focus on medical and therapeutic interventions. We present the conclusions in this Review. First we agreed that the term chemoprevention is inappropriate and suggested that the term preventive therapy better represents this feature of management. Two selective oestrogen-receptor modulators--tamoxifen and raloxifene--are so far the only medical options approved by the US Food and Drug Administration for preventive therapy. Of these tamoxifen has greater efficacy and can be used in premenopausal women, but raloxifene has fewer side-effects. Two newer drugs in this class, lasofoxifene and arzoxifene, also show efficacy and possibly a better overall risk-benefit profile, but need further assessment. Aromatase inhibitors might be more efficacious, and results of prevention trials are eagerly awaited. Newer agents, notably bisphosphonates and metformin, have shown promise in observational studies and need to be assessed in randomised prevention trials. Other agents, such as aspirin, other non-steroidal anti-inflammatory drugs, COX-2 inhibitors, retinoids, rexinoids, and dietary components have limited effects or are in the early phases of investigation. New contralateral tumours in women with breast cancer might be generally useful as a model for prevention, as has been seen for tamoxifen. If valid such a model would facilitate the design of simpler, cheaper, and better-focused trials for assessing new agents.

Polystyrene nanoplastics affect seed germination, cell biology and physiology of rice seedlings in-short term treatments: Evidence of their internalization and translocation.

Agroecosystems represent more and more a huge long-term sink for plastic compounds which inevitably undergo fragmentation, generating micro- and nano-plastics, with potential adverse effects on soil chemistry and living organisms. The present work was focused on the short-term effects of two different concentrations of polystyrene nanoplastics (PSNPs) (0.1 or 1 g L-1 suspensions) on rice seedlings starting from seed germination, hypothesizing that possible acute effects on seedlings could depend on oxidative damage trigged by PSNPs internalization. As shown by TEM analysis, PSNPs were absorbed by roots and translocated to the shoots, affected root cell ultrastructure, the germination process, seedling growth and root mitotic activity, inducing cytogenetic aberration. Treatments were not correlated with increase in oxidative stress markers, but rather with a different pattern of their localization both in roots and in shoots, impairing H2O2 homeostasis and membrane damage, despite the adequate antioxidant response recorded. The harmful effects of PSNPs on cell biology and physiology of rice seedlings could be caused not only by a direct action by the PSNPs but also by changes in the production/diffusion of ROS at the tissue/cellular level.

Early evidence of the impacts of microplastic and nanoplastic pollution on the growth and physiology of the seagrass Cymodocea nodosa.

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous in natural habitats and the risks their presence poses to marine environments and organisms are of increasing concern. There is evidence that seagrass meadows are particularly prone to accumulate plastic debris, including polystyrene particles, but the impacts of this pollutant on seagrass performance are currently unknown. This is a relevant knowledge gap as seagrasses provide multiple ecosystem services and are declining globally due to anthropogenic impact and climate-change-related stressors. Here, we explored the potential effects of a 12 day-exposure of seagrasses to one concentration (68 µg/L) of polystyrene MPs and NPs on the growth, oxidative status, and photosynthetic efficiency of plants using the foundation species Cymodocea nodosa as a model. Among plant organs, adventitious roots were particularly affected by MPs and NPs showing complete degeneration. The number of leaves per shoot was lower in MPs- and NPs-treated plants compared to control plants, and leaf loss exceeded new leaf production in MPs-treated plants. MPs also reduced photochemical efficiency and increased pigment content compared to control plants. Shoots of NPs-treated plants showed a greater oxidative damage and phenol content than those of control plants and MPs-treated plants. Biochemical data about oxidative stress markers were consistent with histochemical results. The effects of MPs on C. nodosa could be related to their adhesion to plant surface while those of NPs to entering tissues. Our study provides the first experimental evidence of the potential harmful effects of MPs/NPs on seagrass development. It also suggests that the exposure of seagrasses to MPs/NPs in natural environments could have negative consequences on the functioning of seagrass ecosystems. This stresses the importance of implementing cleaning programs to remove all plastics already present in marine habitats as well as of undertaking specific actions to prevent the introduction of these pollutants within seagrass meadows.

Leaf UV-B Irradiation and Mycorrhizal Symbionts Affect Lettuce VOC Emissions and Defence Mechanisms, but Not Aphid Feeding Preferences.

Arbuscular mycorrhizal fungi (AMF) and ultraviolet-B radiation (UV-B) play important roles in plant-insect interactions by altering plant physiology and histology. We hypothesized that UV-B-induced oxidative stress was mitigated by AMF symbiosis. In this study, we conducted a multifactorial experiment to explore lettuce plant response to AMF inoculation and UV-B exposure (0.4 W m-2; 16 h d-1; 2 weeks), either together or individually, as well as the interaction with the polyphagous insect pest Myzus persicae (Sulzer). Lettuce plants subjected to UV-B radiation showed an increase in callose and oxidative stress indicators, as well as a decrease in stomatal density. Mycorrhizal colonization cancelled out the effect of UV-B on stomatal density, while the symbiosis was not affected by UV-B treatment. The plant volatile emission was significantly altered by UV-B treatment. Specifically, the non-terpene 1-undecene abundance (+M/+UVB: 48.0 ± 7.78%; -M/+UVB: 56.6 ± 14.90%) was increased, whereas the content of the non-terpene aldehydes decanal (+M/+UVB: 8.50 ± 3.90%; -M/+UVB: 8.0 ± 4.87%) and undecanal (+M/+UVB: 2.1 ± 0.65%; -M/+UVB: 1.20 ± 1.18%) and the sesquiterpene hydrocarbons (+M/+UVB: 18.0 ± 9.62 %; -M/+UVB: 19.2 ± 5.90%) was decreased. Mycorrhization, on the other hand, had no significant effect on the plant volatilome, regardless of UV-B treatment. Aphid population was unaffected by any of the treatments, implying a neutral plant response. Overall, this study provides new insights about the interactions among plants, UV-B, and AMF, outlining their limited impact on a polyphagous insect pest.

Risk of second breast cancer according to estrogen receptor status and family history.

A recent study reported an increased risk of contralateral estrogen-negative breast cancer after a first primary estrogen-negative breast cancer. Our study aims to confirm this result and to evaluate how the risk of second breast cancer occurrence is affected by family history of breast cancer and anti-estrogen treatment. We included all 4,152 women diagnosed with breast cancer between 1995 and 2007, using data from the population-based Geneva Cancer Registry. We compared the incidence of second breast cancer among patients according to estrogen receptor (ER) status with that expected in the general population by age-period Standardized Incidence Ratios (SIRs). Among the cohort, 63 women developed second breast cancer. Patients with ER-positive first tumors had a decreased risk of second breast cancer occurrence (SIR: 0.67, 95% CI: 0.48-0.90), whereas patients with ER-negative primary tumors had an increased risk (SIR: 1.98, 95% CI: 1.19-3.09) limited to ER-negative second tumors (SIR: 7.94, 95% CI: 3.81-14.60). Patients with positive family history had a tenfold (SIR: 9.74, 95% CI: 3.57-21.12) higher risk of ER-negative second tumor which increased to nearly 50-fold (SIR: 46.18, 95% CI: 12.58-118.22) when the first tumor was ER-negative. Treatment with anti-estrogen decreased the risk of second ER-positive tumors but not ER-negative tumors. The risk of second ER-negative breast cancer is very high after a first ER-negative tumor, in particular among women with strong family history. Surveillance and prevention of second cancer occurrence should consider both ER status of the first tumor and family history.

Synchrotron Radiation Spectroscopy and Transmission Electron Microscopy Techniques to Evaluate TiO2 NPs Incorporation, Speciation, and Impact on Root Cells Ultrastructure of Pisum sativum L. Plants.

Biosolids (Bs) for use in agriculture are an important way for introducing and transferring TiO2 nanoparticles (NPs) to plants and food chain. Roots of Pisum sativum L. plants grown in Bs-amended soils spiked with TiO2 800 mg/kg as rutile NPs, anatase NPs, mixture of both NPs and submicron particles (SMPs) were investigated by Transmission Electron Microscopy (TEM), synchrotron radiation based micro X-ray Fluorescence and micro X-ray Absorption Near-Edge Structure (µXRF/µXANES) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). TEM analysis showed damages in cells ultrastructure of all treated samples, although a more evident effect was observed with single anatase or rutile NPs treatments. Micro-XRF and TEM evidenced the presence of nano and SMPs mainly in the cortex cells near the rhizodermis. Micro-XRF/micro-XANES analysis revealed anatase, rutile, and ilmenite as the main TiO2 polymorphs in the original soil and Bs, and the preferential anatase uptake by the roots. For all treatments Ti concentration in the roots increased by 38-56%, however plants translocation factor (TF) increased mostly with NPs treatment (261-315%) and less with SMPs (about 85%), with respect to control. In addition, all samples showed a limited transfer of TiO2 to the shoots (very low TF value). These findings evidenced a potential toxicity of TiO2 NPs present in Bs and accumulating in soil, suggesting the necessity of appropriate regulations for the occurrence of NPs in Bs used in agriculture.

Impact of obesity on diagnosis and treatment of breast cancer.

In this population-based study, we evaluated the impact of obesity on presentation, diagnosis and treatment of breast cancer. Among all women diagnosed with invasive breast cancer in the canton Geneva (Switzerland) between 2003 and 2005, we identified those with information on body mass index (BMI) and categorized them into normal/underweight (BMI <25 kg/m(2)), overweight (BMI > or =-<30 kg/m(2)) and obese (BMI > or =30 kg/m(2)) women. Using multivariate logistic regression, we compared tumour, diagnosis and treatment characteristics between groups. Obese women presented significantly more often with stage III-IV disease (adjusted odds ratio [OR(adj)]: 1.8, 95% CI: 1.0-3.3). Tumours > or =1 cm and pN2-N3 lymph nodes were significantly more often impalpable in obese than in normal/underweight patients (OR(adj) 2.4, [1.1-5.3] and OR(adj) 5.1, [1.0-25.4], respectively). Obese women were less likely to have undergone ultrasound (OR(adj) 0.5, [0.3-0.9]) and MRI (OR(adj) 0.3, [0.1-0.6]) and were at increased risk of prolonged hospital stay (OR(adj) 4.7, [2.0-10.9]). This study finds important diagnostic and therapeutic differences between obese and lean women, which may impair survival of obese women with breast cancer. Specific strategies are needed to optimize the care of obese women with or at risk of breast cancer.

Effect of Zinc Priming on Salt Response of Wheat Seedlings: Relieving or Worsening?

In an attempt to alleviate salt-induced damage, the application of ZnO nanoparticles has been suggested. As the use of these particles has also been associated with phytotoxicity, to better clarify the effect of zinc and its possible mitigation of salt stress, we treated wheat seedlings with ZnO (nanoparticles or their bulk-scale counterparts, amended either in the growth medium, NPs and B, or sprayed on the leaves, SPNPs and SPB) with or without subsequent treatment with salt. Growth, photosynthetic parameters, zinc and ion concentration, and in situ and biochemical determination of oxidative stress in wheat leaves and/or in roots were considered. Both Zn and NaCl significantly inhibited growth and induced severe alterations in root morphology. Oxidative stress and damage decreased or increased under ZnO treatment and in saline conditions depending on the organ and on the size and mode of application of particles. In spite of the higher stress conditions often recorded in treated leaves, neither pigment concentration nor photochemical efficiency were decreased. A large variability in the effects of ZnO treatment/priming on seedling salt response was recorded; however, the presence of a cumulative negative effect of priming and salt stress sometimes observed calls for caution in the use of ZnO in protection from saline stress.

Genotoxicity of the food additive E171, titanium dioxide, in the plants Lens culinaris L. and Allium cepa L.

E171 (titanium dioxide, TiO2), an authorized foods and beverage additive, is also used in food packaging and in pharmaceutical and cosmetic preparations. E171 is considered to be an inert and non-digestible material, not storable in animal tissues, but the possible presence of TiO2 nanoparticles (NP) may present a risk to human health and the environment. We determined the presence of 15% TiO2 NP in a commercial E171 food additive product, by electron microscopy. The biological effects of E171 were assessed in Lens culinaris and Allium cepa for the following endpoints: percentage of germination, root elongation, mitotic index, presence of chromosomal abnormalities, and micronuclei. The results indicated low phytotoxicity but dose-dependent genotoxicity. We also observed internalization of TiO2 NP and ultrastructural alterations in the root systems.

Exploring the interaction between polystyrene nanoplastics and Allium cepa during germination: Internalization in root cells, induction of toxicity and oxidative stress.

With the aim to investigate the mechanisms of action of nano plastics (nano PS) on plants, seeds of Allium cepa were germinated for 72 h in the presence of polystyrene nano PS (50 nm size, at concentrations of 0.01, 0.1 and 1 g L-1) and, subsequently, roots were analysed by a multifaceted approach. No effect was induced by any concentration of nano PS on the percentage of seed germination while root growth was inhibited by 0.1 and 1 g L-1 nano PS. Cytological analysis of the root meristems indicated cytotoxicity (reduction of mitotic index) and genotoxicity (induction of cytogenetic anomalies and micronuclei) starting from the lowest dose. Moreover, the biochemical and histochemical analysis of oxidative stress markers gave evidence of stress induction, especially at the highest doses. Damages reported could be due to mechanical surface contact in root external layers, as evidenced by histological localization, and to the internalization of nano PS in different cellular compartments, observed under TEM. The present research underlines the hazardous nature of nano PS, that for their ability to be internalized into crop plants, can enter into different trophic levels of the food chain.

Modulation of the defence responses against Cd in willow species through a multifaceted analysis.

Willow, due to the extensive root system, high transpiration rates and ability to accumulate large amounts of cadmium, is considered particularly useful for green remediation practices. In this study two different willow species, Salix viminalis and Salix alba, were used to assess possible differences in their ability of cadmium accumulation and to analyse in detail the physiology of their response to treatments with this metal using a multidisciplinary approach. Plants were grown in hydroponics and treated with 0, 50 and 100 µM Cd2+ (CdCl2) for 7 and 14 days. Cadmium content, oxidative stress, both evaluated by biochemical and histochemical techniques, antioxidant response, leaf stomatal conductance and photosynthetic efficiency were measured in control and treated roots and/or leaves. The two willow species removed cadmium with a high efficiency from the growth solution; however, the highest contents of Cd recorded in plants grown in the presence of the lower Cd concentrations suggest a limited capacity of metal accumulation. No photochemical limitation characterised treated plants, probably due to the ability to store large amounts of Cd in the root compartment, with reduction of damage to the photosynthetic machinery. S. viminalis, able to uptake cadmium also in the root apical region, seemed to be a more efficient accumulator than S. alba and, thanks to a relatively higher antioxidant response, did not show a higher level of oxidative stress. On the basis of the above, the two plant species, in particular S. viminalis, are confirmed as useful for cadmium phytostabilisation/phytoextraction.

TiO2 nanoparticles may alleviate cadmium toxicity in co-treatment experiments on the model hydrophyte Azolla filiculoides.

The hydrophyte Azolla filiculoides can be a useful model to assess if TiO2 NPs may in some way alleviate the Cd injuries and improve the ability of the plant to cope with this metal. With this mechanistic hypothesis, after a pre-treatment with TiO2 NPs, A. filiculoides plants were transferred to cadmium-contaminated water with or without TiO2 nanoparticles. After 5 days of treatment, cadmium uptake, morpho-anatomical, and physiological aspects were studied in plants. The continuous presence of TiO2 nanoparticles, though not increasing the uptake of cadmium in comparison with a priming treatment, induced a higher translocation of this heavy metal to the aerial portion. Despite the translocation factor was always well below 1, cadmium contents in the fronds, generally greater than 100 ppm, ranked A. filiculoides as a good cadmium accumulator. Higher cadmium contents in leaves did not induce damages to the photosynthetic machinery, probably thanks to a compartmentalization strategy aimed at confining most of this pollutant to less metabolically active peripheral cells. The permanence of NPs in growth medium ensured a better efficiency of the antioxidant apparatus (proline and glutathione peroxidase and catalase activities) and induced a decrease in H2O2 content, but did not suppress TBARS level.