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To evaluate the risks of hair dye exposure, we investigated cellular and molecular effects of Arianor Ebony dye, which is a mixture of azo and anthraquinone dyes, used in the composition of the black color. Cytotoxicity, genotoxicity, and gene expression of relevant molecules of apoptotic and oxidative stress mechanisms were investigated in HepG2 cells exposed to Arianor Ebony. Results showed that the dye did not induce cytotoxicity to exposed cells at a concentration up to 50 µg/mL compared to the negative control. However, genotoxic assays indicated that the dye was able to damage the genetic material at a concentration of 25 µg/mL, with induction factor values of exposed cells two- to five-fold higher than those recorded for the negative control. Moreover, the lowest observed effect concentration was 12.5 µg/mL. For gene expression, relevant changes were observed in cytochrome c and caspase 9, which decreased in cells incubated with the dye in a dose-dependent manner when compared with the negative control. In parallel, the expression of genes for antioxidant enzymes was increased in exposed cells, suggesting the presence of metabolic routes that protect cells against the toxic effect of the dye, avoiding exacerbated cellular death. Results suggested that the dye disrupted cellular homeostasis through mitochondrial dysfunction, which may be hazardous to human health. Thus, further investigations are necessary to deeply understand the mechanisms of action of the dye, considering its toxic potential found in our ex vivo assays.

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To evaluate the risks of hair dye exposure, we investigated cellular and molecular effects of Arianor Ebony dye, which is a mixture of azo and anthraquinone dyes, used in the composition of the black color. Cytotoxicity, genotoxicity, and gene expression of relevant molecules of apoptotic and oxidative stress mechanisms were investigated in HepG2 cells exposed to Arianor Ebony. Results showed that the dye did not induce cytotoxicity to exposed cells at a concentration up to 50 µg/mL compared to the negative control. However, genotoxic assays indicated that the dye was able to damage the genetic material at a concentration of 25 µg/mL, with induction factor values of exposed cells two- to five-fold higher than those recorded for the negative control. Moreover, the lowest observed effect concentration was 12.5 µg/mL. For gene expression, relevant changes were observed in cytochrome c and caspase 9, which decreased in cells incubated with the dye in a dose-dependent manner when compared with the negative control. In parallel, the expression of genes for antioxidant enzymes was increased in exposed cells, suggesting the presence of metabolic routes that protect cells against the toxic effect of the dye, avoiding exacerbated cellular death. Results suggested that the dye disrupted cellular homeostasis through mitochondrial dysfunction, which may be hazardous to human health. Thus, further investigations are necessary to deeply understand the mechanisms of action of the dye, considering its toxic potential found in our ex vivo assays.

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Magnetic nanocomposites based on maghemite nanoparticles supported (ex situ route) on styrene- divinilbenzene (Sty-DVB) copolymer templates were produced and characterized for their structure and morphology. The as-produced nanocomposites were further chemically-treated with different oxidant agents and surface-coated with stearic acid. X-ray diffraction and transmission electron microscopy data show that the incorporated nanoparticles are preserved despite the aggressive chemical treatments employed. From the dynamical susceptibility measurements performed on the nanocomposites, the values of the saturation magnetization (76 emu/g) and the effective magnetic anisotropy (1.7 × 104 J/m³) were obtained, in excellent agreement with the values reported in the literature for maghemite. This finding strongly supports the preservation of the magnetic properties of the supported nanosized maghemite throughout the entire samples' processing.

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Magnetic nanoparticles (NPs) have attracted great attention owing to their applications in the biomedical field. In the present work, maghemite (γFe2O3) NPs of 6.5 nm were prepared using a sonochemical method and used to prepare magnetic beads through silanization with 3-aminopropyltrimethoxysilane (APTS). Subsequently, amino groups in the resulting APTS-γFe2O3 beads were converted to carboxylic acid (CARB-γFe2O3) through the succinic anhydride reaction, as confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and dynamic light scattering (DLS) measurements. The size of these beads was measured as 12 nm and their hydrodynamic diameter as 490 nm, using TEM analysis and DLS, respectively. The CARB-γFe2O3 beads were further functionalized by immobilizing rabbit antibodies on their surfaces; the immobilization was confirmed by flow cytometry and ionic strength. The samples were further characterized by Mössbauer spectroscopy and DC magnetization measurements. Studies on magnetic relaxivities showed that magnetic beads present great potential for application in MR imaging.

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Jatropha gossypiifolia L. (Euphorbiaceae) is widely used in popular medicine. However, further toxicological studies are necessary for its reliable use. The present study aimed to evaluate the cytotoxic, genotoxic, and mutagenic effects of ethanolic and aqueous leaf extracts of J. gossypiifolia, using the test system Allium cepa. In addition, the phytochemical profile of the extracts was also obtained. Seeds of A. cepa were subjected to different concentrations of the two extracts (0.001, 0.01, 0.1, 1, and 10 mg/mL). Distilled water was used for the negative control and methyl methanesulfonate (4 x 10(-4) M) and trifluralin (0.84 ppm) for the positive controls. The values of mitotic index at all concentrations of ethanolic extract and at 0.1, 1, and 10 mg/mL aqueous extract showed a significant decrease. Alterations, such as chromosome adherence, C-metaphases, chromosome bridges, nuclear buds, and micronuclei were verified in both extracts but chromosome loss indicating genotoxic activity was observed only in the ethanolic extract. Presence of micronuclei on administration of the extracts, also indicated mutagenic action at the chromosome level. In the ethanolic extract, aneugenicity seemed to be the main activity, probably as a result of the action of terpenes and/or flavonoids, whereas in the aqueous extract, clastogenic action appeared to be the principal activity, presumably as a consequence of the effect of flavonoids and/or saponins. Thus, we suggest that the extracts of this species should be used with great caution for medicinal purpose.

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This study evaluated the mutagenicity and antimutagenicity of inulin in a chromosomal aberration assay in cultures of the meristematic cells of Allium cepa. The treatments evaluated were as follows: negative control--seed germination in distilled water; positive control--aqueous solution of methyl methanesulfonate (10 µg/mL MMS); mutagenicity--aqueous solutions of inulin (0.015, 0.15, and 1.50 µg/mL); and antimutagenicity--associations between MMS and the different inulin concentrations. The antimutagenicity protocols established were pre-treatment, simultaneous simple, simultaneous with pre-incubation, and post-treatment. The damage reduction percentage (DR%) was 43.56, 27.77, and 55.92% for the pre-treatment; -31.11, 18.51, and 7.03% for the simultaneous simple; 30.43, 19.12, and 21.11% for the simultaneous with pre-incubation; and 64.07, 42.96, and 53.70% for the post-treatment. The results indicated that the most effective treatment for inhibiting damages caused by MMS was the post-treatment, which was followed by the pre-treatment, suggesting activity by bioantimutagenesis and desmutagenesis. The Allium cepa assay was demonstrated to be a good screening test for this type of activity because it is easy to perform, has a low cost, and shows DR% that is comparable to that reported studies that evaluated the prevention of DNA damage in mammals by inulin.

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Ganglionic synapses have the capability to express long-term potentiation (gLTP) after application of a brief high-frequency stimulus. It has been suggested a possible role of gLTP in some cardiovascular diseases. Although a number of characteristics of gLTP have been described, the precise locations and mechanisms underlying gLTP are not completely known. Current findings support two major conflicting presynaptic and postsynaptic hypotheses. The presynaptic hypothesis posits a presynaptic increase in acetylcholine (ACh) release, whereas the postsynaptic hypothesis proposes a long-lasting enhancement of the nicotinic response on the postsynaptic membrane. An alternative trans-synaptic hypothesis proposes the presynaptic release of a cotransmitter from large dense core vesicles, which postsynaptically enhances synaptic efficacy and accounts for gLTP. Here, we review the studies of LTP, with emphasis on gLTP in mammals, and we examine the findings that support the presynaptic, the postsynaptic and the trans-synaptic hypotheses. We then review our data on the contribution of calcium to gLTP as an approach to elucidate the mechanisms of gLTP. Data on the contribution of calcium to gLTP and on prolonged high-frequency stimulus-dependent fading of LTP have led us to support the trans-synaptic process as responsible for gLTP. Finally, we present a formal working model for the mechanisms of gLTP.

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The chemical stability of magnetic particles is of great importance for their applications in medicine and biotechnology. The most challenging problem in physics of disordered systems of magnetic nanoparticles is the investigation of their dynamic properties. The chemical coprecipitation process was used to synthesize spherical magnetite nanoparticles of 14 nm. The as-prepared magnetite nanoparticles have been aged in the matrix. Magnetic properties and aging effect were studied by Mössbauer spectroscopy at temperatures ranging from 77 to 300 K, and X-ray diffraction. At room temperature, the Mössbauer spectrum showed superparamagnetic behavior of the particles, while well-defined sextets were observed at 77K, indicating a blocked regime. The superparamagnetic magnetite nanoparticles can be used as microbead biosensors.

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Photoacoustic spectroscopy was used to investigate magnetic nanocomposites incorporating nanosized maghemite particles into styrene-divinylbenzene copolymer template. Typical photoacoustic features were observed in bands C, S and L in the wavelength region of 300-1000 nm. The relative intensity of band-C scaled with the nominal concentration of nanosized maghemite incorporated into the polymeric template whereas the lowest relative intensity of band-S was found in the sample in which the template polymerization took place in the presence of the highest polar-like reaction medium. X-ray diffraction and transmission electron microscopy were used to characterize the magnetic nanosized phase as maghemite, with average particle diameter of 6.9 nm (sample Est34), 7.0 nm (sample H30), and 7.9 nm (sample Em15).

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Photoacoustic spectroscopy (PAS) has revolutionized the fields of biological, environmental, and agricultural sciences. It is a very simple, sensitive, and non-destructive technique that allows the determination of optical properties of bio-samples. The in vivo chlorophylls of the leaf have a recorded maximum absorption peak at 675 nm as against 665 nm of the in vitro chlorophylls. The intensity of purple pigmentation in leaves of Blepharocalyx salicifolius (Kunt) O. Berg, is inversely correlated to the soil moisture levels, leaf water content and leaf water potentials. The applicability of PAS to biological samples was discussed. It allows the validation of existing emission models which are important for atmospheric process. A portable device for photoacoustic spectroscopy of plants and other photosynthetic tissues, cells and organelles is provided. Further, there is provided a method to measure photosynthesis of such tissues, cells and organelles.

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