Staphylococcal carriage and antibodies to toxic shock syndrome toxin 1 in Brazilian women

A study of 215 women from different socioeconomic backgrounds in Botucatu, Brazil, was conducted to reveal possible clues why toxic shock syndrome (TSS) is seldom diagnosed in Brazil. Of the 215 women, 79 were colonized with Staphylococcus aureus either in the nasal passages and/or in the vaginal area, which is comparable to the colonization of individuals in the developed countries Thirteen of the women were colonized with S. aureus that produced toxic shock syndrome toxin-1 (TSST-1), the toxin responsible for the majority of cases of TSS. Eleven strains produced enterotoxin B, the only enterotoxin implicated in TSS, primarily in non-menstrual TSS. Enterotoxin A was produced by 15 strains and is commonly associated with the production of TSST-1, but has not been implicated in TSS. Seven strains produced enterotoxin D and one strain produced enterotoxin C, but these have not been implicated in TSS. Only 9 women used tampons which may be a major reason for the lack of menstrual TSS in Brazil, Only two of the 49 women whose sera were examined for the presence of antibodies to TSST-1 had no or very low antibody titers, the major protection against the development of TSS, both menstrual and non-menstrual TSS. This is a lower percentage than has been observed in the developed countries. Although another possibility for the lack of TSS in Brazil is the failure to recognize the disease, however, the results of this limited study indicate the importance of low usage of tampons and the high percentage of individuals with antibodies to TSST-1. The socioeconomic backgrounds of the participants were of little significance.

Toxic mechanism of nickel exposure on cardiac tissue

The incidence of cardiovascular disease has increased in the general population, and cardiac damage is indicated as one important cause of mortality. In addition, pollution and metal exposure have increased in recent years. For this reason, toxic effects of metals, such as nickel, and their relation to cardiac damage should be urgently established. Although free radical-mediated cellular damage and reactive oxygen species have been theorized as contributing to the nickel mechanism of toxicity, recent investigations have established that free radicals may be important contributors to cardiac dysfunction. However, there is little information on the effect of nickel exposure on markers of oxidative stress in cardiac tissue. Nickel exposure (Ni2+ 100 mg L-1 from NiSO4) significantly increased lipoperoxide and total lipid concentrations in cardiac tissue. We also observed increased serum levels of cholesterol (59%), lactate dehydrogenase (LDH-64%), and alanine transaminase (ALT-30%) in study animals. The biochemical parameters recovered to the control values with tocopherol intake (0.2 mg 200 g-1). Vitamin E alone significantly decreased the lipoperoxide concentration and increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the heart. Since no alterations were observed in catalase and GSH-Px activities by nickel exposure while SOD activities were decreased, we conclude that superoxide radical (O2 -) generated by nickel exposure is of primary importance in the pathogenesis of cardiac damage. Tocopherol, by its antioxidant activity, decreased the toxic effects of nickel exposure on heart of rats.

Toxic mechanism of cadmium exposure on cardiac tissue

The presence of toxic substances in the workplace environment requires systematic evaluation of exposure and health status in exposed subjects. Cadmium is a highly toxic element found in water. Although free mediated cellular damage and reactive oxygen species (ROS), had been theorized as contributing to the cadmium mechanism of toxicity, and recent investigations have established that free radicals may be important contributors to cardiac dysfunction, there is little information on the effect of cadmium exposure on markers of oxidative stress in cardiac tissue. Cadmium exposure (Cd2+ - 100 mg/1-from CdCl2) in drinking water, during 15 days, significantly increased lipoperoxide and decreased the activities of superoxide dismutase and glutathione peroxidase. No alterations were observed in catalase activity in heart of rats with cadmium exposure. We also observed decreased glycogen and glucose concentration and increased total lipid content in cardiac tissue of rats with cadmium exposure. The decreased activities of alanine transaminase and aspartate transaminase reflected decreased metabolic protein degradation, and increased lactate dehydrogenase activity was related with increases in capacity of glycolysis. Since the metabolic pathways were altered by cadmium exposure, we can conclude that Cd2+ exposure induced ROS and initiate some series of events that occur in the heart and resulted in metabolic pathways alterations.

Effect of hydrated sodium calcium aluminosilicate on the prevention of the toxic effects of ochratoxin

We studied the efficacy of hydrated sodium calcium aluminosilicate (HSCAS) as an inhibitor of the toxic effects of ochratoxin in broilers from 1 to 42 d of age. A total of 288 broilers was distributed into four treatments with four replicates of 18 birds each: T1, control; T2, 0.25% HSCAS; T3, 2 ppm of ochratoxin; T4, 0.25% HSCAS + 2 ppm ochratoxin. The parameters evaluated were feed intake; weight gain; feed conversion; relative weights of the liver, kidneys, and bursa; and serum levels of Ca, P, total protein (TP), aspartate aminotransferase (AST) and γ-glutamiltransferase (GGT). Ochratoxin in the diet negatively affected (P < 0.05) all performance parameters evaluated when the birds were 21 and 42 d of age. However, HSCAS did not affect performance, and there was no interaction between HSCAS and dietary ochratoxin. The liver and the kidneys of birds fed ochratoxin with or without HSCAS were relatively heavier (P < 0.05) than those of the control birds, demonstrating the influence of ochratoxin, but not of HSCAS, on the relative weight of these organs. Although the bursa of birds exposed to ochratoxin with or without HSCAS had a lower relative weight as compared to control birds, the difference was not significant. Ca, P, and TP serum levels were lower (P < 0.05) in birds exposed to ochratoxin, whereas AST and GGT levels were higher (P < 0.05) in these birds. These results reflect that ochratoxin in the diet impaired the productivity indexes and that HSCAS did not improve these parameters.

Toxic and genotoxic effects of trivalent and hexavalent chromium - A review

During the last years, the emission of heavy metals to the environment has increased, causing a severe negative impact to the ecosystems and seriously compromising human health due to their mutagenic potential. Tri- (III) and hexavalent (VI) chromium (Cr) constitute the oxidative states of the metal chromium that are active in living organisms. These two oxidation states of the chromium differ with regards to their cellular effects, mainly due to the different abilities they possess in relation to easy of transport through biological membranes. Cr VI is transported into the cell through transference channels of endogenous anions that are isostructural and isoelectronical to Cr VI, such as SO 4 -2 and HPO 4 -2. On the other hand, Cr III is unable to diffuse through the cell membrane. Its existence inside the cells is generally due to the reduction of Cr VI, the endocytosis, or the absortion by the cells via phagocytosis. Cr III acts directly on the DNA molecule, while Cr VI reacts little with this molecule. In the ecosystem, however, Cr VI is more dangerous since this is the form that presents greater reactivity with biological membranes, crossing them and being easily incorporated into the cell. In the cell it is biotransformed to Cr III, a potentially mutagenic molecule. In vivo and in vitro studies have shown that organisms exposed to Cr VI present greater induction to a variety of damages to the DNA molecule. Among the damages induced by Cr, changes in the structure of the DNA molecule have been reported, with breaks of the major chain and base oxidation. In the organisms, these alterations generate chromosomal aberrations, micronucleus formation, sister chromatid exchanges, and errors in DNA synthesis.

Quantitative analysis of potentially toxic metals in alginates for dental use

Alginate is one the materials most employed in practice to make dental impressions. Substances like zinc, cadmium and lead silicate, which are included in several alginate brands with the aim of improving their physical, chemical and mechanical properties, are a source of serious concern as regards their toxicity. The most serious chronic effect of oral exposure to cadmium is renal toxicity. Assimilation of lead has deleterious effects on the gastrointestinal tract, hematopoietic system, cardiovascular system, central and peripheral nervous systems, kidneys, immune system, and reproductive system. Chronic oral exposures to zinc have resulted in hypochromic and microcyte anemia in some individuals. The aim of the present study was to measure the cadmium, lead and zinc contents of seven brands of alginate for dental use on sale in Brazil. The samples were weighed and placed in the Teflon cups of a closed-system microwave oven. Aqua regia (4mL concentrated HCI:HNO3, 3:1 v/v) and hydrofluoric acid (2mL concentrated HF) were added to the samples, which were then subjected to heating. The samples were then cooled to room temperature and diluted to 25 mL in deionized water in a volumetric glass flask. The samples were diluted in duplicate and analyzed against a reagent blank. The analyses were performed in an atomic absorption flame spectrophotometer. Neither lead nor cadmium was detected. Zinc contents ranged from 0.001% to 1.36% by weight. The alginates exhibited low contents of the metals under study and gave no cause for concern regarding toxicity; even so, it is advisable to monitor potentially toxic materials continually and to analyze their plasmatic levels in the professionals working with them.

Detection of enterotoxin and toxic shock syndrome toxin 1 genes in Staphylococcus, with emphasis on coagulase-negative staphylococci

The detection of staphylococcal enterotoxins is decisive for the confirmation of an outbreak and for the determination of the enterotoxigenicity of strains. Since the recognition of their antigenicity, a large number of serological methods for the detection of enterotoxins in food and culture media have been proposed. Since immunological methods require detectable amounts of toxin, molecular biology techniques represent important tools in the microbiology laboratory. In the present study, polymerase chain reaction (PCR) was used to identify genes responsible for the production of enterotoxins and toxic shock syndrome toxin 1 (TSST-1) in S. aureus and coagulase-negative staphylococci (CNS) isolated from patients and the results were compared with those obtained by the reverse passive latex agglutination (RPLA) assay. PCR detection of toxin genes revealed a higher percentage of toxigenic S. aureus strains (46.7%) than the RPLA method (38.3%). Analysis of the toxigenic profile of CNS strains showed that 26.7% of the isolates produced some type of toxin, and one or more toxin-specific genes were detected in 40% of the isolates. These results suggests the need for further studies in order to better characterize the pathogenic potential of CNS and indicate that attention should be paid to the toxigenic capacity of this group of microorganisms.

Separation of the toxic zierin from Zollernia ilicifolia by high speed countercurrent chromatography

Preliminary pharmacological assays of the 70% methanol extract from the leaves of the Brazilian medicinal plant Zollernia ilicifolia Vog. (Fabaceae) showed analgesic and antiulcerogenic effects. Previous analyses have shown that this extract contains, besides flavonoid glycosides and saponins, a toxic cyanogenic glycoside. Flavonoids and saponins are compounds reported in literature with antiulcerogenic activity. In this work, we developed a methodology to separate the cyanogenic glycoside from these compounds in order to obtain enough amount of material to perform pharmacological assays. The cyanogenic glycoside zierin (2S)-β-D-glucopyranosyloxy-(3-hydroxy-phenyl)- acetonitrile was separated from the other components by high speed countercurrent chromatography (HSCCC). The solvent system used was composed of chloroform-methanol-n-propanol-water (5:6:1:4, v/v/v/v). This technique led to the separation of zierin from the possible active compounds of Zollernia ilicifolia.

Influence of hydric stress in the production of toxic principles in Nerium oleander L.

Many plants utilized in the urban center shows substances considered toxic whose production could be influenced by some factors, like hydric stress, including ornamental Nerium oleander L., widely used in gardens in various parts of the world, which presents production of cardioative glucosides, considered toxic. This study had the objective to evaluate the effect of field capacity in the biomass and the level of cardioative glucosides in seedlings of Nerium oleander. The experiment was carried at UNIDERP, in Campo Grande City, Mato Grosso do Sul State, Brazil, at the University for Development of State and Pantanal Region, using the experimental delineation in randomized blocks. There were 4 treatments (25%; 50%; 75% and 100% of the field capacity), 5 replications and 4 plants by parcel, totalling 80 plants. The evaluations were realized 60 days after the seedlings were planted. The quantitative analysis of the cardioative glucosides was realized by gravimetric test, after selective extraction of the glucosides. Were conclude that increase of the quantity of water in the soil raised the biomass production until 75% of the field capacity and increased the level of cardioative glucosides, showing that water management is very important and should be provided only the necessary to development of the plant.

Photoelectrocatalysis based on Ti/TiO2 nanotubes removes toxic properties of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1 from aqueous chloride samples

This work describes the efficiency of photoelectrocatalysis based on Ti/TiO2 nanotubes in the degradation of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1 and to remove their toxic properties, as an alternative method for the treatment of effluents and water. For this purpose, the discoloration rate, total organic carbon (TOC) removal, and genotoxic, cytotoxic and mutagenic responses were determined, using the comet, micronucleus and cytotoxicity assays in HepG2 cells and the Salmonella mutagenicity assay. In a previous study it was found that the surfactant Emulsogen could contribute to the low mineralization of the dyes (60% after 4h of treatment), which, in turn, seems to account for the mutagenicity of the products generated. Thus this surfactant was not added to the chloride medium in order to avoid this interference. The photoelectrocatalytic method presented rapid discoloration and the TOC reduction was ≥87% after 240min of treatment, showing that photoelectrocatalysis is able to mineralize the dyes tested. The method was also efficient in removing the mutagenic activity and cytotoxic effects of these three dyes. Thus it was concluded that photoelectrocatalysis was a promising method for the treatment of aqueous samples. © 2013 Elsevier Ltd.

Toxic effects of daily applications of 10% carbamide peroxide on odontoblast-like MDPC-23 cells

Background. Tooth bleaching has been widely studied, mainly due to the possible undesirable effects that can be caused by this esthetic procedure. The cytotoxicity of the bleaching agents and its components to pulp cells has been demonstrated in several researches. The aim of this study was to evaluate the toxic effects of successive applications of 10% carbamide peroxide (CP) gel on odontoblast-like cells. Materials and methods. Enamel-dentin discs obtained from bovine incisors were adapted to artificial pulp chambers (APCs). The groups were formed as follows: G1: Without treatment (control group); G2: 10% carbamide peroxide, CP (five applications/one per day); G3: 10% CP (one unique application); and G4: 35% hydrogen peroxide, HP (three applications of 15 min each). After treatment, cell metabolism (MTT), alkaline phosphatase (ALP) activity and plasma membrane damage (flow cytometry) were analyzed. Results. Reductions in cell metabolism and alkaline phosphatase activity along with severe damage of the cytoplasmic membrane were noted in G2. In G3, no damage was observed, compared to the control group. Intermediary values of toxicity were obtained after 35% HP application. Conclusion. It can be concluded that one application of 10% CP did not cause toxic effects in odontoblast-like cells, but the successive application of this product promoted severe cytotoxic effects. The daily application of the bleaching agents, such as used in the at-home bleaching technique, can increase the damages caused by this treatment to the dental pulp cells. © 2013 Informa Healthcare.

A recepção crítica de Harold Bloom no meio acadêmico brasileiro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cyanobacteria detection in Guarapiranga Reservoir (São Paulo State, Brazil) using Landsat TM and ETM+ images

Algae bloom is one of the major consequences of the eutrophication of aquatic systems, including algae capable of producing toxic substances. Among these are several species of cyanobacteria, also known as blue-green algae, that have the capacity to adapt themselves to changes in the water column. Thus, the horizontal distribution of cyanobacteria harmful algae blooms (CHABs) is essential, not only to the environment, but also for public health. The use of remote sensing techniques for mapping CHABs has been explored by means of bio-optical modeling of phycocyanin (PC), a unique inland waters cyanobacteria pigment. However, due to the small number of sensors with a spectral band of the PC absorption feature, it is difficult to develop semi-analytical models. This study evaluated the use of an empirical model to identify CHABs using TM and ETM+ sensors aboard Landsat 5 and 7 satellites. Five images were acquired for applying the model. Besides the images, data was also collected in the Guarapiranga Reservoir, in São Paulo Metropolitan Region, regarding the cyanobacteria cell count (cells/mL), which was used as an indicator of CHABs biomass. When model values were analyzed excluding calibration factors for temperate lakes, they showed a medium correlation (R²=0.81, p=0.036), while when the factors were included the model showed a high correlation (R²=0.96, p=0.003) to the cyanobacteria cell count. The empirical model analyzed proved useful as an important tool for policy makers, since it provided information regarding the horizontal distribution of CHABs which could not be acquired from traditional monitoring techniques.

Low toxic effects of a whitening strip to cultured pulp cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Adhesive Restorations on Diffusion of H2O2 Released from a Bleaching Agent and Its Toxic Effects on Pulp Cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)