Hydroxypropyl methylcellulose-sugarcane bagasse adsorbents for removal of 17α-ethinylestradiol from aqueous solution and freshwater.

Adsorbents made of hydroxypropyl methylcellulose (HPMC) and sugarcane bagasse (BG) microparticles were applied for the separation of 17α-ethinylestradiol (EE2) from aqueous solution in batch, and from aqueous solution and freshwater in fixed-bed columns. HPMC chains and BG microparticles were crosslinked by the esterification with citric acid. The adsorbents presented compression modulus values that increased from 208 ± 20 kPa (pure HPMC) to 917 ± 90 kPa, when the content of BG particles added to HPMC was 50 wt% (HPMC50BG). The porosity (~ 97%), specific surface area (1.16 ± 0.10 m2/g) and swelling degree (20 ± 1 g water/g) values were not affected by the addition of BG particles. The adsorption isotherms determined for EE2 on HPMC and on HPMC50BG fitted to the Langmuir and Freundlich models; the adsorption capacity of HPMC was slightly higher than that of composite HPMC50BG. Nevertheless, the addition of BG particles rendered outstanding mechanical reinforcement and dimensional stability to the adsorbents. The adsorption was driven by (i) hydrophobic interactions between EE2 methylene and aromatic groups and HPMC methyl groups, as evidenced by FTIR spectroscopy, and (ii) H bonds between HPMC and EE2 hydroxyl groups, as revealed by the adsorption enthalpy change (ΔHads) of - 45 kJ/mol. Column adsorption experiments of EE2 from aqueous solution on HPMC and HPMC50BG indicated adsorptive capacity (q0) values of 8.06 mg/g and 4.07 mg/g, respectively. These values decreased considerably for the adsorption of EE2 from river water, probably due to the competition of EE2 with humic substances dissolved in natural water. The HPMC adsorbents could be recycled retaining up to 83% of the original efficiency.

CTAB-modified carboxymethyl cellulose/bagasse cryogels for the efficient removal of bisphenol A, methylene blue and Cr(VI) ions: Batch and column adsorption studies.

The simultaneous removal of organic and inorganic pollutants from water requires multifunctional adsorbents. Cryogels of carboxymethyl cellulose (CMC) and sugarcane bagasse (BG) were modified with cetyltrimethylammonium bromide (CTAB) micelles for the adsorption of methylene blue (MB), Cr(VI) ions and bisphenol A (BPA) separately, in binary or ternary aqueous mixtures. Batch adsorption studies of MB and Cr(VI) and BPA on the CMCBG-CTAB adsorbents indicated removal capacities of 100%, 70% and 95%, respectively. MB adsorbed as multilayers on the CMCBG walls by electrostatic interaction, whereas Cr(VI) and BPA adsorbed on the cationic CTAB micelles surface and hydrophobic core of CTAB micelles, respectively. The breakthrough curves obtained for pure adsorbates and their mixtures showed that the adsorption of Cr(VI) ions increased (i) ~ 3.5 times in binary mixture with BPA or in the ternary mixture, in comparison to pure Cr(VI) solution, and (ii) 1.4 times in binary mixture with MB molecules, due to synergistic effects. In the presence of Cr(VI) ions in binary or ternary mixtures, the adsorption of MB was dramatically reduced due to screening effects. The adsorption of BPA was not significantly affected by the presence of MB or Cr(VI). The adsorbents were recycled five times without significant efficiency loss.

Dietary zinc deficiency or supplementation during gestation increases breast cancer susceptibility in adult female mice offspring following a J-shaped pattern and through distinct mechanisms.

Zinc is required for fetal development and is involved in key processes associated with breast carcinogenesis. We evaluated whether maternal zinc deficiency or supplementation during gestation influences female offspring susceptibility to breast cancer in adulthood. C57BL/6 mice consumed during gestation control (30 p.p.m. zinc), zinc-deficient (8 p.p.m) or zinc-supplemented (45 p.p.m.) diets. Maternal zinc supplementation increased in female mice offspring the incidence of chemically-induced mammary adenocarcinomas that were heavier, compared to control group. This was accompanied by a decreased number of terminal end buds, increased cell proliferation and apoptosis, and increased tumor suppressors p21, p53 and Rassf1, Zfp382 and Stat3 expression in mammary glands, as well as increased zinc status. Although maternal zinc deficiency did not alter the incidence of these lesions, it also induced heavier mammary adenocarcinomas, compared to control group. These effects were accompanied by a decreased number of terminal end buds, increased proto-oncogenes c-Myc and Lmo4 expression and H3K9Me3 and H4K20Me3 epigenetic marks in mammary glands of offspring, and decreased zinc status and increased levels of oxidative marker malondialdehyde. The data suggest that both maternal zinc deficiency and supplementation during gestation programmed increased breast cancer susceptibility in adult mice offspring following a J-shaped pattern through distinct mechanisms.

A fast degrading PLLA composite with a high content of functionalized octacalcium phosphate mineral phase induces stem cells differentiation.

Octacalcium phosphate (OCP) was synthesized yielding a combination of OCP and hydroxyapatite (HA) with a ratio of 90:10 (OCP/HA). A method was developed to functionalize the surface of the apatite using lauroyl chloride to improve the dispersion of the mineral phase in a poly(L-lactide) (PLLA) polymeric matrix. Infrared spectra and thermal gravimetric analysis confirmed the presence of laurate on the surface of calcium phosphate (CaP) particles. Neat HA particles were also functionalized with lauryl chloride for comparative purposes. PLLA/OCP/HA-laurate (PLLA/OCP/HA-L) and PLLA/HA-laurate (PLLA/HA-L) composites were fabricated by electrospinning method. The presence of the functional groups resulted in significant improvement of the dispersion of OCP/HA and HA particles into the polymeric matrix, allowing inclusion of up to 40% of mineral phase. Electrospun fibrous biocomposites of PLLA/CaP containing up to 40% in mineral phase were obtained without compromising their mechanical properties. Measurements of mass loss and calcium release in vitro showed that OCP/HA is more soluble than HA. The bioactivity of the composites was investigated by simulated body fluid test (SBF). Although both PLLA/OCP/HA-L and PLLA/HA-L fibers can form CaP crystals on their surface after exposition in SBF, the results demonstrate a significant enhancement in mineralization when OCP/HA is the mineral phase in the composite instead neat HA. Furthermore, the obtained PLLA/OCP/HA-L electrospun fibers favored the proliferation and differentiation of stem cells from human exfoliated deciduous teeth and mouse calvaria-derived preosteoblastic cells into mineralized osteoblasts. This new material is proposed as fast degrading CaP biocomposite for bone and teeth applications.

Can in vivo surface dental enamelmicrobiopsies be used to measure remote lead exposure?

Measuring lead in the surface dental enamel (SDE) using biopsies is a rapid, safe, and painless procedure. The dental enamel lead levels (DELLs) decrease from the outermost superficial layer to the inner layer of dental enamel, which becomes crucial for the biopsy depth (BD) measurement. However, whether the origin of lead found in SDE is fully endogenous is not yet established. There is also controversy about the biopsy protocol. The aims of this study were to investigate if DELLs are altered by extrinsic contamination (A) and to evaluate the real geometric figure formed by the erosion provoked by biopsy procedure and the respective BD in SDE (B). To accomplish the aim A, lead from 90 bovine incisor crowns lead was determined by graphite furnace atomic absorption spectrometer as a function of exposure time and lead concentration. Two biopsies were performed in each tooth, before and after lead exposure. Six 15-tooth groups differed by exposure time (1 or 30 min) and lead concentrations (A. 0 mg/L-placebo, B. 0.01 mg/L-standard for drinking water, or C. 0.06 mg/L-concentration found in contaminated groundwater). Phosphorus was determined by an inductively coupled plasm optical emission spectrometer to quantify the enamel removed. To compare intakes/losses of lead in SDE among the groups, values of DELL differences between before and after lead exposure were compared by ANOVA (p < 0.05). To attain the objective B, one extracted human permanent tooth was studied by confocal Raman microscopy. Lead measurements and the surface profile were determined. There was no difference in DELL among the groups (p = 0.964). The biopsy bottom surface area, analyzed by microscopy, showed an irregular area, with regions of peaks and valleys, where areas with depth ranging from 0.2 (peaks) to 1.8 µm (valleys) (± 0.1 µm) could be found. BD carried out in vivo is commonly calculated using the cylinder height formula. The real BD was shown to be very similar to already published data. In conclusion, the SDE of erupted teeth does not seem to be susceptible to environmental lead intake, being thus reliable to measure remote exposures to lead.

Formation of a pseudotumor in total hip arthroplasty using a tribological metal-polyethylene pair / Formação de pseudotumor na artroplastia total do quadril com par tribológico metal-polietileno

The aim here was to report a case of a young adult patient who evolved with tumor formation in the left thigh, 14 years after revision surgery on hip arthroplasty. Davies in 2005 made the first description of this disease in patients undergoing metal-on-metal hip arthroplasty. Over the last decade, however, pseudotumors around metal-on-polyethylene surfaces have become more prevalent. Our patient presented with increased volume of the left thigh 8 years after hip arthroplasty revision surgery. Two years before the arising of the tumor in the thigh, a nodule in the inguinal region was investigated to rule out a malignant neoplastic process, but the results were inconclusive. The main preoperative complaints were pain, functional limitation and marked reduction in the range of motion of the left hip. Plain radiographs showed loosening of acetabular and femoral, and a large mass between the muscle planes was revealed through magnetic resonance imaging of the left thigh. The surgical procedure consisted of resection of the lesion and removal of the components through lateral approach. In respect of total hip arthroplasty, pseudotumors are benign neoplasms in which the bearing surface consists of metal-on-metal, but they can also occur in different tribological pairs, as presented in this case.

Relatar o caso de um paciente adulto jovem que evoluiu com tumoração na coxa esquerda após 14 anos de uma cirurgia de revisão de artroplastia do quadril. Davies em 2005 descreveu esta afecção em pacientes submetidos a atroplastia de quadril com par tribológico metal-metal, mas na última década é possível achar relatos de pseudotumores em superfície metal-polietileno. O paciente iniciou queixa de aumento de volume da coxa esquerda após oito anos da cirurgia de revisão da artroplastia do quadril. Dois anos antes do aparecimento da tumoração da coxa, a investigação para descartar um processo neoplásico maligno de um nódulo em região inguinal foi inconclusiva. Suas principais queixas pré-operatórias eram dor, limitação funcional e marcada redução da amplitude de movimento do quadril esquerdo. As radiografias do membro acometido evidenciavam soltura dos componentes acetabular e femoral, e uma grande massa entre os planos musculares se revelou à ressonância magnética da coxa esquerda. A abordagem cirúrgica consistiu de ressecção intralesional da coxa esquerda, seguida da retirada dos componentes pela via lateral direta. No âmbito da cirurgia de artroplastia de quadril, os pseudotumores são neoplasias benignas cujo par tribológico consiste em metal -metal, mas podem também ocorrer em diferentes pares tribológicos, como neste caso.

Ultrasmall cationic superparamagnetic iron oxide nanoparticles as nontoxic and efficient MRI contrast agent and magnetic-targeting tool.

Fully dispersible, cationic ultrasmall (7 nm diameter) superparamagnetic iron oxide nanoparticles, exhibiting high relaxivity (178 mM(-1)s(-1) in 0.47 T) and no acute or subchronic toxicity in Wistar rats, were studied and their suitability as contrast agents for magnetic resonance imaging and material for development of new diagnostic and treatment tools demonstrated. After intravenous injection (10 mg/kg body weight), they circulated throughout the vascular system causing no microhemorrhage or thrombus, neither inflammatory processes at the mesentery vascular bed and hepatic sinusoids (leukocyte rolling, adhesion, or migration as evaluated by intravital microscopy), but having been spontaneously concentrated in the liver, spleen, and kidneys, they caused strong negative contrast. The nanoparticles are cleared from kidneys and bladder in few days, whereas the complete elimination from liver and spleen occurred only after 4 weeks. Ex vivo studies demonstrated that cationic ultrasmall superparamagnetic iron oxide nanoparticles caused no effects on hepatic and renal enzymes dosage as well as on leukocyte count. In addition, they were readily concentrated in rat thigh by a magnet showing its potential as magnetically targeted carriers of therapeutic and diagnostic agents. Summarizing, cationic ultrasmall superparamagnetic iron oxide nanoparticles are nontoxic and efficient magnetic resonance imaging contrast agents useful as platform for the development of new materials for application in theranostics.

In Vitro Evaluation of Cu, Fe, and Zn Bioaccessibility in the Presence of Babassu Mesocarp.

In vitro gastrointestinal digestion of babassu mesocarp in the absence and presence of milk and lignin was performed to evaluate the bioaccessibility of Cu, Fe, and Zn. Extractions using NaOH solutions (pH 7 and 12) were carried out to evaluate the interactions of Cu(II), Fe(III), and Zn(II) with the extracted compounds and with the washed mesocarp. Studies using reference solutions showed a decrease in the free concentration of the elements in the presence of mesocarp. Phytate, a component present in the mesocarp, can be the main compound responsible for the elements' interactions with mesocarp. Lignin increases the elements' soluble fractions; however, the elements' concentrations in the dialyzed fractions, representing the bioaccessible portion, were very low. On the other hand, Cu, Fe, and Zn bioaccessibility in milk was not influenced by the mesocarp.

Formation of a pseudotumor in total hip arthroplasty using a tribological metal-polyethylene pair.

The aim here was to report a case of a young adult patient who evolved with tumor formation in the left thigh, 14 years after revision surgery on hip arthroplasty. Davies in 2005 made the first description of this disease in patients undergoing metal-on-metal hip arthroplasty. Over the last decade, however, pseudotumors around metal-on-polyethylene surfaces have become more prevalent. Our patient presented with increased volume of the left thigh 8 years after hip arthroplasty revision surgery. Two years before the arising of the tumor in the thigh, a nodule in the inguinal region was investigated to rule out a malignant neoplastic process, but the results were inconclusive. The main preoperative complaints were pain, functional limitation and marked reduction in the range of motion of the left hip. Plain radiographs showed loosening of acetabular and femoral, and a large mass between the muscle planes was revealed through magnetic resonance imaging of the left thigh. The surgical procedure consisted of resection of the lesion and removal of the components through lateral approach. In respect of total hip arthroplasty, pseudotumors are benign neoplasms in which the bearing surface consists of metal-on-metal, but they can also occur in different tribological pairs, as presented in this case.

Relatar o caso de um paciente adulto jovem que evoluiu com tumoração na coxa esquerda após 14 anos de uma cirurgia de revisão de artroplastia do quadril. Davies em 2005 descreveu esta afecção em pacientes submetidos a artroplastia de quadril com par tribológico metal­metal, mas na última década é possível achar relatos de pseudotumores em superfície metal­polietileno. O paciente iniciou queixa de aumento de volume da coxa esquerda após oito anos da cirurgia de revisão da artroplastia do quadril. Dois anos antes do aparecimento da tumoração da coxa, a investigação para descartar um processo neoplásico maligno de um nódulo em região inguinal foi inconclusiva. Suas principais queixas pré-operatórias eram dor, limitação funcional e marcada redução da amplitude de movimento do quadril esquerdo. As radiografias do membro acometido evidenciavam soltura dos componentes acetabular e femoral, e uma grande massa entre os planos musculares se revelou à ressonância magnética da coxa esquerda. A abordagem cirúrgica consistiu de ressecção intralesional da coxa esquerda, seguida da retirada dos componentes pela via lateral direta. No âmbito da cirurgia de artroplastia de quadril, os pseudotumores são neoplasias benignas cujo par tribológico consiste em metal -metal, mas podem também ocorrer em diferentes pares tribológicos, como neste caso.

Iron bioavailability of different maize genotypes developed in a breeding program: in vitro and in vivo studies

The objective of this study was to evaluate iron bioavailability of maize genotypes, and analyze the correlation between in vitro and in vivo methods. Dialysable iron was analyzed in 13 genotypes from which 5 were selected for the biological assay. Mean iron content of the genotypes (n=13) was 17.93±2.93 mg kg-1. Phytate varied from 0.77% to 1.03%; phytate: iron molar ratio from 30.64 to 55.41; and soluble iron from 13.17 to 39.63%. The highest value for dialysable iron was 19.14%. In the biological assay, the control group, that received ferrous sulphate, did not present significant difference between the genotypes for Hb gain, Hb gain per gram of iron consumed and HRE. Hb gain did not present a significant correlation with in vitro assay. However, there were positive correlations varying from 0.653 to 0.809. The maize genotypes evaluated presented a good bioavailability since the genotypes showed the same result in hemoglobin gain than control group.

Biodisponibilidade de ferro de diferentes genótipos de milho desenvolvidos em programa de melhoramento genético: estudos in vitro e in vivo. O objetivo deste estudo foi avaliar a biodisponibilidade do ferro de genótipos de milho e analisar a correlação entre métodos in vitro e in vivo. Ferro dialisável foi analisado em13 genótipos, a partir do qual 5 foram selecionados para o ensaio biológico. A média de teor de ferro dos genótipos (n= 13) foi 17,93 ± 2,93 mg kg-1. O teor de fitato variou de 0,77% a 1,03%; razão molar fitato:ferro de 30,64 a 55,41; e ferro solúvel de 13,17 a 39,63%.O valor mais alto para o ferro dialisável foi 19,14%. No ensaio biológico, o grupo controle, que recebeu sulfato ferrso, não apresentou diferença significativa entre os genótipos no ganho Hb, ganho de Hb por grama de ferro consumido e HRE. Ganho de Hb não apresentou correlação significativa com o ensaio in vitro. No entanto, houve correlações positivas variando de 0,653 a 0,809. Os genótipos de milho avaliados apresentaram uma boa biodisponibilidade uma vez que os genótipos apresentaram o mesmo resultado quanto ao ganho de hemoglobina em relação ao grupo controle.

Iron bioavailability of different maize genotypes developed in a breeding program: in vitro and in vivo studies.

The objective of this study was to evaluate iron bioavailability of maize genotypes, and analyze the correlation between in vitro and in vivo methods. Dialysable iron was analyzed in 13 genotypes from which 5 were selected for the biological assay. Mean iron content of the genotypes (n = 13) was 17.93 +/- 2.93 mg kg(-1). Phytate varied from 0.77% to 1.03%; phytate: iron molar ratio from 30.64 to 55.41; and soluble iron from 13.17 to 39.63%. The highest value for dialysable iron was 19.14%. In the biological assay, the control group, that received ferrous sulphate, did not present significant difference between the genotypes for Hb gain, Hb gain per gram of iron consumed and HRE. Hb gain did not present a significant correlation with in vitro assay. However, there were positive correlations varying from 0.653 to 0.809. The maize genotypes evaluated presented a good bioavailability since the genotypes showed the same result in hemoglobin gain than control group.

Urinary copper excretion before and after oral intake of d-penicillamine in parents of patients with Wilson's disease.

BACKGROUND: Urinary copper excretion higher than 100 µg/24 h is useful for diagnosing Wilson's disease. d-Penicillamine challenge test may produce higher levels than 1400 µg/24 h, allowing for better diagnostic accuracy. This study investigated whether heterozygotes reach this value and compared copper serum levels, ceruloplasmin, and urinary copper excretion before and after administering d-penicillamine to the parents of Wilson's disease patients. METHODS: Fifty parents of adult patients were enrolled to obtain copper serum levels and ceruloplasmin along with 24-h urinary copper excretion before and after administering 1g d-penicillamine. RESULTS: Serum ceruloplasmin and copper levels were significantly lower in fathers than in mothers (mean 21.8×27.8 mg%; 71.4×88.0 µg%; p ≤ 0.001). The mean of basal 24-h urinary copper excretion was higher in fathers (26.2×18.7 µg/24 h, p=0.01), but did not differ between the genders after d-penicillamine (521.7×525.3, range 31.6-1085.1 µg/24h, p=0.8). CONCLUSIONS: The mean values of serum copper, ceruloplasmin, and basal urinary copper excretion were different between males and females. The current diagnostic threshold of 24-h urinary copper excretion after d-penicillamine was not reached by heterozygotes. The increased urinary copper excretion after d-penicillamine challenge was much higher than fivefold the upper limit of normal urinary copper excretion in the majority of heterozygotes and should not be taken into account when diagnosing Wilson's disease.

Influence of microwave heating on fluoride, chloride, nitrate and sulfate concentrations in water.

This paper describes a study about the influence of microwave radiation using closed vessels on fluoride, chloride, nitrate and sulfate concentrations in aqueous media. The experiments were processed by heating water using PFA vessels and a microwave cavity oven, determining the anions by ion chromatography. The influence of the exposure time, the atmospheric composition, the kind of heating (water bath or microwave radiation) and the possible formation of hydrogen peroxide were investigated. The limits of quantification for fluoride, chloride, nitrate and sulfate were respectively of 0.17, 0.15, 0.55 and 0.57 µg L(-1), and precision, expressed as RSD, was <4% for all considered anions. The hydrogen peroxide was quantified by spectrophotometry, and the limit of quantification and precision were 24 µg L(-1) and <5% (n=10), respectively. The results demonstrate a significant increase in the anion concentration levels (between 63 and 89%) when microwave heating was used in comparison with heating by water bath. In addition, these changes observed can be mainly attributed to the species transfers, either between gaseous (atmospheric gases) and liquid (water) phases for nitrate, or between vessels walls and water for fluoride, chloride and sulfate. Additionally, hydrogen peroxide concentration higher than 45 µg L(-1) was determined when water was exposed to microwave radiation.

Association of dental enamel lead levels with risk factors for environmental exposure / Associação de níveis de chumbo no esmalte dentário com fatores de risco para exposição ambiental / Asociación de niveles de plomo en el esmalte dental con factores de riesgo a la exposición ambiental

OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95 percent CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95 percent CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95 percent CI: 0.56;3.03) and smoking (OR = 1.66; 95 percent CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

OBJETIVO: Analisar fatores de risco no ambiente domiciliar associados com altos níveis de chumbo no esmalte dentário superficial. MÉTODOS: Estudo transversal conduzido com 160 adolescentes brasileiros (14 a 18 anos), residentes em bairros pobres do município de Bauru, SP, de agosto a dezembro de 2008. A concentração de chumbo no esmalte dentário foi avaliada por microbiópsias ácidas do esmalte dentário superficial, quantificada por espectrometria de absorção atômica com forno de grafite e a concentração de fósforo foi medida por espectrometria de absorção óptica com plasma indutivamente acoplado. Os pais dos adolescentes responderam a questionário sobre possível exposição prévia (cinco primeiros anos de vida do adolescente) a chumbo decorrente de fontes de contaminação bem conhecidas. Usou-se regressão logística para identificar associações entre concentração de chumbo no esmalte e fatores de risco ambientais. Covariáveis familiares e sociais foram incluídas nos modelos. RESULTADOS: Os resultados sugerem que os jovens avaliados foram expostos a fontes de chumbo durante seus primeiros anos de vida. Os fatores de risco associados com o desfecho foram residir em área contaminada por chumbo ou nas suas proximidades (OR = 4,49; IC 95 por cento: 1,69;11,97) e ter convivido, no mesmo domicílio, com pessoa que trabalhava em fábrica de tintas, pigmentos, cerâmicas ou baterias (OR = 3,43; IC 95 por cento: 1,31;9,00). Ter usado, em casa, cerâmica vitrificada, brinquedos de baixa qualidade ou piratas, ter aplicado zarcão em portões de ferro sem cobertura esmaltada ou armazenar baterias de carro usadas na residência (OR = 1,31; IC 95 por cento: 0,56;3,03) e hábito de fumar não foram associados com altas concentrações de chumbo no esmalte dentário (OR = 1,66; IC 95 por cento: 0,52;5,28). CONCLUSÕES: O esmalte dentário superficial pode ser utilizado como marcador de exposição ambiental passada ao chumbo e as concentrações encontradas desse metal estão ligadas a fontes bem conhecidas de contaminação por chumbo.

OBJETIVO: Analizar factores de riesgo en el ambiente domiciliar asociados con altos niveles de plomo en el esmalte dental superficial. MÉTODOS: Se realizó estudio transversal con 160 adolescentes brasileros (14 a 18 años), residentes en urbanizaciones pobres del municipio de Bauru, SP, de agosto a diciembre de 2008. La concentración de plomo en el esmalte dental fue evaluada por micro biopsias ácidas del esmalte dental superficial, cuantificada por espectrometría de absorción atómica con horno de grafito y la concentración de fósforo fue medida por espectrometría de absorción óptica con plasma inductivamente acoplado. Los padres de los adolescentes respondieron a cuestionario sobre posible exposición previa (5 primeros años de vida del adolescente) al plomo producto de fuentes de contaminación bien conocidas. Se usó regresión logística para identificar asociaciones entre concentración de plomo en el esmalte y factores de riesgo ambientales. Covariables familiares y sociales fueron incluidas en los modelos. RESULTADOS: Los resultados sugieren que los jóvenes evaluados fueron expuestos a fuentes de plomo durante sus primeros años de vida. Los factores de riesgo asociados con el resultado fueron residir en área contaminada por plomo o en sus proximidades (OR=4,49; IC 95 por ciento: 1,69;11,97) y haber convivido, en el mismo domicilio, con persona que trabajaba en fábrica de tintas, pigmentos, cerámicas o baterías (OR= 3,43; IC 95 por ciento: 1,31;9,00). Haber usado, en casa, cerámica vitrificada, juegos de baja calidad o piratas, haber aplicado zircón en portones de hierro sin cobertura esmaltada o almacenar baterías de carro usadas en la residencia (OR= 1,31; IC 95 por ciento: 0,56-3,03) y hábito de fumar no fueron asociados con altas concentraciones de plomo en el esmalte dental (OR=1,66; IC 95 por ciento: 0,52;5,28). CONCLUSIONES: El esmalte dental superficial puede ser utilizado como marcador de exposición ambiental pasada al plomo y las concentraciones encontradas de dicho metal están relacionadas con fuentes bien conocidas de contaminación por plomo.

Association of dental enamel lead levels with risk factors for environmental exposure.

OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

An in vitro comparison of nickel and chromium release from brackets.

This study aimed at comparing amounts of nickel (Ni) and chromium (Cr) released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5%). International standard ISO 10271/2001 was applied to provide test methods. Each bracket was immersed in 0.5 ml of synthetic saliva (SS) or artificial plaque fluid (PF) over a period of 28 days at 37 degrees Celsius. Solutions were replaced every 7 days, and were analyzed by spectrometry. The Kruskal-Wallis test was applied. Amounts of Ni release in SS (microg L(-1) per week) varied between groups from 'bellow detection limits' to 694, and from 49 to 5,948.5 in PF. The group of brackets made of cobalt-chromium alloy, with the least nickel content, did not release the least amounts of Ni. Amounts of Cr detected in SS and in PF (microg L(-1) per week) were from 1 to 10.4 and from 50.5 to 8,225, respectively. It was therefore concluded that brackets from different manufacturers present different corrosion behavior. Further studies are necessary to determine clinical implications of the findings.

An in vitro comparison of nickel and chromium release from brackets

This study aimed at comparing amounts of nickel (Ni) and chromium (Cr) released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5 percent). International standard ISO 10271/2001 was applied to provide test methods. Each bracket was immersed in 0.5 ml of synthetic saliva (SS) or artificial plaque fluid (PF) over a period of 28 days at 37ºC. Solutions were replaced every 7 days, and were analyzed by spectrometry. The Kruskal-Wallis test was applied. Amounts of Ni release in SS (µg L-1 per week) varied between groups from "bellow detection limits" to 694, and from 49 to 5,948.5 in PF. The group of brackets made of cobalt-chromium alloy, with the least nickel content, did not release the least amounts of Ni. Amounts of Cr detected in SS and in PF (µg L-1 per week) were from 1 to 10.4 and from 50.5 to 8,225, respectively. It was therefore concluded that brackets from different manufacturers present different corrosion behavior. Further studies are necessary to determine clinical implications of the findings.