Resumen La injuria o lesión renal aguda (LRA) es la mayor causa de mortalidad debido a las mordeduras por cascabeles Crotalus durissus terrificus. Se estudió la instalación precoz de LRA, en ratas, inducida por el veneno de Crotalus durissus terrificus después de 2 h de su inoculación y la atenuación por el antiveneno. Se utilizaron diversos biomarcadores para monitorear LRA en ausencia o presencia del antiveneno. Ratas Wistar machos fueron divididos en 5 grupos (n=5 por grupo): G1, ratas inoculadas con solución salina (control); G2, ratas inoculadas con veneno (6 mg kg-1 dosis, vía intraperitoneal), y sacrificadas después de 2 h para evaluar LRA; G3 y G4, ratas inoculadas con 0.9% de solución salina esterilizada o antiveneno luego de 2 h después de inoculado el veneno, respectivamente, y monitoreadas hasta su muerte o hasta 24 h después de inoculado el veneno; y G5, ratas inoculadas con antiveneno solo y monitoreadas durante 24 h. Las muestras de sangre, orina, y tejido renal fueron colectadas inmediatamente después de la muerte de los animales para evaluar estrés oxidativo, alteraciones hematológicas y bioquímicas, y daño histológico renal. El veneno causó LRA dentro de las 2 h (G2) persistiendo durante más de 8,2 ± 1,6 h (G3), estando esto confirmado por el incremento de urea sanguínea, creatinina, y proteinuria renal; estos aumentos disminuyeron con la aplicación del antiveneno. No se observaron alteraciones en las concentraciones de proteínas sanguíneas en G2 y G3, mientras que se encontraron incrementos en glutatión reducido sanguíneo, glutatión peroxidasa y TBARS plasmática (pero no en catalasa), que disminuyeron con la aplicación del antiveneno aunque en diferente grado. No ocurrieron alteraciones marcadas de plaquetas o leucocitos, mientras que el aumento de glóbulos rojos observado luego de 8,2 h de la inoculación con veneno, disminuyó con el antiveneno. El daño renal glomerular y tubular fue más importante luego de 2 h de la inoculación con veneno y posteriormente disminuyó. El veneno causó LRA precoz a las 2 h, con efectos variables sobre la peroxidación lipídica y el estrés oxidativo. El antiveneno redujo el daño renal, conforme lo demostrado por la disminución en la urea sanguínea y por la normalización de la proteinuria, aunque no se observó protección contra la peroxidación lipídica.

Abstract Acute kidney injury (AKI) is the major cause of mortality following bites by the South American rattlesnake Crotalus durissus terrificus. We investigated the early onset of Crotalus durissus terrificus venom-induced AKI in rats within 2 h of venom injection and its attenuation by antivenom. Several biomarkers were used to monitor AKI in the absence or presence of antivenom. Male Wistar rats were divided into five groups (n=5 each): G1, rats injected with saline (control); G2, rats injected with venom (6 mg kg-1, intraperitoneally) and euthanized after 2 h to evaluate AKI; G3 and G4, rats injected with 0.9% sterile saline or antivenom 2 h after venom, respectively, and monitored until death or up to 24 h post-venom, and G5, rats injected with antivenom alone and monitored for 24 h. Blood, urine and renal tissue samples were collected immediately after death to assess oxidative stress, hematological and biochemical alterations, and renal histological damage. Venom caused AKI within 2 h (G2) that persisted for up to 8.2 ± 1.6 h (G3), as confirmed by increases in blood urea, creatinine, and renal proteinuria; these increases were attenuated by antivenom. There were no changes in blood protein concentrations in G2 and G3, whereas there were increases in blood reduced glutathione, glutathione peroxidase, and plasma TBARS (but not in catalase) that were attenuated to varying extents by antivenom. There were no marked changes in platelets or leukocytes, but an increase in erythrocytes after 8.2 h with venom alone was attenuated by antivenom. Renal glomerular and tubular damage was greatest after 2 h post-venom groups alone was attenuated by antivenom. Renal glomerular and tubular damage was greatest after 2 h post-venom and declined thereafter. Venom caused early-onset AKI, with variable effects on lipid peroxidation and oxidative stress. Antivenom attenuated the AKI, as shown by the decrease in blood urea and the normalization of proteinuria, without protecting against lipid peroxidation.

RESUMO Fibroína (FB) e nanocelulose bacteriana (BC) são produtos naturais que podem ser usados na biomedicina, nas indústrias eletrônicas e de alimentos e outras áreas. Todos eles apresentam biocompatibilidade, podendo ser utilizados para diversos fins. A mistura de fibroína e nanocelulose bacteriana foi projetada para produzir um material biocompatível para ser aplicado com um dispositivo médico. Por esse motivo, o objetivo deste trabalho foi avaliar as propriedades estruturais da mistura de BC e FB. Assim, FB foi extraída do Bombyx mori e a BC foi produzida por processo de fermentação utilizando Gluconacetobacter xylinus. As membranas compostas de BC-FB foram produzidas por contato de imersão por 24 horas, a 25 °C, em 100 rpm, sem agente reticulante. Após a produção, as amostras de membrana foram secas e caracterizadas por espectroscopia de Infravermelho com Transformada de Fourier (espectroscopia FTIR), propriedades mecânicas, eficiência de intumescimento, microscopia eletrônica de varredura (MEV) e microtomografia computadorizada (µCt). Os resultados indicam que as membranas porosas com ligações de hidrogênio obtidas apresentaram morfologia porosa anisiotrópica, fechada e interconectada. As características morfométricas, que se assemelham a um favo de mel e consistem em uma estrutura longa com alta conectividade e alta porosidade total, amplificam as áreas de aplicações da mistura BC-FB, com potencial utilização com dispositivos optoeletrônicos, em áreas que variam desde ambiental à engenharia tecidual. Além disso, a produção por contato de imersão permitirá o processo de alta qualidade e o desenvolvimento de material de rótulo verde.

ABSTRACT Fibroin (FB) and bacterial nanocellulose (BC) are natural products, being used in biomedicine, electronics, food industries and other areas. Both show biocompatibility, able to be used for many different purposes. The blending of fibroin and bacterial nanocellulose was design to produce a biocompatible material to be applied with a medical device. For this reason, the objective of this work was to evaluate the structure properties of the blending of BC and FB. Thus, FB was extracted from Bombyx mori and BC was produced by fermentation process utilizing Gluconacetobacter xylinus. The membranes composed of BC-FB were produced by immersion contact for 24 hours, at 25°C, in 100rpm; without crosslinking agent. After the production the membrane samples were dried and characterized by Fourier transform infrared spectroscopy (FTIR spectroscopy), mechanical proprieties, swelling efficiency, scanning electron microscopy (SEM) and computerized microtomography (µCt). Results indicate that the hydrogen-bonded porous membranes obtained displayed anisiotropic, closed and interconnected porous morphology. The morphometric characteristics, which resemble a honeycomb and consist of a long structure with high connectivity and high total porosity, amplify the areas of BC-FB blend applications, with potential utilization with optoelectronic devices, in areas ranging from environmental to tissue engineering. Furthermore, the production by immersion contact will allow the upscale process and the development of green label material.

Arsenic is considered a semimetal, and its wide distribution in the Earth's crust in different chemical forms, including organic and inorganic species, has a great deal of influence on the mechanisms of toxicity. Exposure to arsenic can be either through occupational practice (use of pesticides) or by the consumption of water and food containing the element. Rice is considered a fundamental constituent of the basic diet of Brazilians and is usually cultivated in flooded conditions. Such a plantation system results in an increased amount of As in the soil and hence a greater accumulation of As in the plant, which is highlighted by the inorganic species' classification as highly toxic. Besides the use of mitigation techniques to reduce the toxicological risk, monitoring the concentration of As and its chemical species in rice and rice products is required through the establishment of legislation in the area. Thus, some world organizations are conducting improved research to determine and establish acceptable concentrations of As and its chemical species in rice, e. g., in 2012, FDA researchers described a chemical speciation methodology for As in rice and rice products. Hence, the application of existing chemical speciation methods and the establishment of parameters for ensuring food security and exposure risk assessment deserve particular consideration.

The diversity of the V3 loop tip motif sequences of HIV-1 subtype B was analyzed in patients from Botucatu (Brazil) and Montpellier (France). Overall, 37 tetrameric tip motifs were identified, 28 and 17 of them being recognized in Brazilian and French patients, respectively. The GPGR (P) motif was predominant in French but not in Brazilian patients (53.5% vs 31.0%), whereas the GWGR (W) motif was frequent in Brazilian patients (23.0%) and absent in French patients. Three tip motif groups were considered: P, W, and non-P non-W groups. The distribution of HIV-1 isolates into the three groups was significantly different between isolates from Botucatu and from Montpellier (P < 0.001). A higher proportion of CXCR4-using HIV-1 (X4 variants) was observed in the non-P non-W group as compared with the P group (37.5% vs 19.1%), and no X4 variant was identified in the W group (P < 0.001). The higher proportion of X4 variants in the non-P non-W group was essentially observed among the patients from Montpellier, who have been infected with HIV-1 for a longer period of time than those from Botucatu. Among patients from Montpellier, CD4+ cell counts were lower in patients belonging to the non-P non-W group than in those belonging to the P group (24 cells/µL vs 197 cells/µL; P = 0.005). Taken together, the results suggest that variability of the V3 loop tip motif may be related to HIV-1 coreceptor usage and to disease progression. However, as analyzed by a bioinformatic method, the substitution of the V3 loop tip motif of the subtype B consensus sequence with the different tip motifs identified in the present study was not sufficient to induce a change in HIV-1 coreceptor usage.

Free radicals induce lipid peroxidation, playing an important role in pathological processes. The injury mediated by free radicals can be measured by conjugated dienes, malondialdehyde, 4-hydroxynonenal, and others. However, malondialdehyde has been pointed out as the main product to evaluate lipid peroxidation. Most assays determine malondialdehyde by its reaction with thiobarbituric acid, which can be measured by indirect (spectrometry) and direct methodologies (chromatography). Though there is some controversy among the methodologies, the selective HPLC-based assays provide a more reliable lipid peroxidation measure. This review describes significant aspects about MDA determination, its importance in pathologies and biological samples treatment.

Malondialdehyde (MDA) is one of the lipid peroxidation products widely used as indicator of cellular injury. However, the short-term and the long-term stability of this biomarker remain unclear. The objective of this work was to evaluate the stability of plasmatic MDA at -20 ºC, utilizing thiobarbituric acid (TBA) as derivative in spectrophotometric and chromatographic analysis. The results showed that MDA was stable for 24 h after blood collection, was not stable when stored after alkaline hydrolysis, remained stable for 30 days after TBA derivatization and was stable for 3 days when stored after n-butanol extraction, all at -20 ºC.

INTRODUÇÃO: O cobre é um nutriente essencial para os humanos, e a manutenção dos seus níveis é importante, uma vez que seu metabolismo está envolvido com estresse oxidativo e patologias, como a Doença de Wilson. Neste trabalho, um método de espectrofotometria visível (espectrofotometria Vis) foi validado, aplicado em indivíduos jovens e comparado com espectrometria de absorção atômica com chama (EAA-chama). MÉTODOS: Concentrações séricas de cobre foram medidas por EAA-chama e por espectrofotometria Vis, através da reação de cobre com batocuproína, l = 484 nm. Curvas analíticas em solução aquosa e com adição de padrão foram efetuadas para verificar linearidade, recuperação e precisão do método espectrofotométrico. Amostras de sangue de 12 indivíduos (média de idade 22 anos) foram analisadas por ambos os métodos e comparadas entre si. Os resultados foram expressos em média ± desvio-padrão. RESULTADOS: As curvas com adição de padrão e aquosa (n = 5) apresentaram coeficientes de regressão superiores a 0,99 e de variação inter e intradia inferiores a 15%. Os valores de cobre sérico encontrados para o método espectrofotométrico foram 1,17 ± 0,39 e 0,73 ± 0,14 mg/l para mulheres e homens, respectivamente. Para EAA-chama foram encontrados 1,13 ± 0,43 e 0,59 ± 0,13 mg/l para mulheres e homens, respectivamente. Os resultados mostraram correlação de Pearson significativa (r = 0,946; p < 0,05). Os níveis séricos de cobre foram significativamente maiores em mulheres do que em homens (p < 0,05). CONCLUSÃO: O método espectrofotométrico visível demonstrou ser linear, reprodutível e aplicável, oferecendo uma alternativa confiável à quantificação de cobre por EAA-chama. Além disso, é uma técnica simples, rápida e barata, que pode ser utilizada na rotina laboratorial clínica.

BACKGROUND: Copper is an essential nutrient for humans and maintenance of its adequate levels is important, since its metabolism is involved with oxidative stress and patolologies, such as Wilson's disease. In this work, a visible spectrophotometric method was validated, applied in young subjects and compared to flame atomic absorption spectrometry (FAAS) in serum copper levels determination. METHODS: Serum copper concentrations were measured by FAAS and by spectrophotometry, through copper reaction with bathocuproine, l = 484 nm. Aqueous curves and spiked serum curves were realized to verify linearity, recovery and precision of the visible spectrophotometric method. Blood samples from 12 subjects (mean 22 years) were analyzed in both methodologies and compared to each other. The results were expressed by mean ± standard deviation. RESULTS: Spiked serum and aqueous curves (n = 5) showed coefficient of regression superior to 0.99 and inter and intra-day coefficient of variation lower than 15%. The serum copper values found to Vis spectrophotometric method were 1.17 ± 0.39 and 0.73 ± 0.14 mg/l to women and men, respectively. To FAAS 1.13 ± 0.43 and 0.59 ± 0.13 mg/l were found to women and men, respectively. Both results showed a significant Pearson correlation (r = 0.946; p < 0.05). Besides, serum copper levels were significantly higher in women than in men (p < 0.05). CONCLUSION: The Vis spectrophotometric method demonstrated to be linear, reproducible and applied, offering a reliable alternative to FAAS copper quantification. Moreover, Vis spectrophotometry is a simple, quickly and not expensive technique, and it could be widely used as routine in clinical laboratory.

INTRODUÇÃO: O paraquat, herbicida amplamente utilizado na agricultura, é um produto perigoso, pois pode causar intoxicações fatais, principalmente pela falta de antídoto eficaz para reversão do quadro clínico. Fisiopatologia: Os efeitos toxicológicos são decorrentes da indução ao estresse oxidativo. O órgão-alvo principal é o pulmão, que pode apresentar edema, hemorragia, inflamação intersticial e fibrose, culminando com falência respiratória grave e morte. Além disso, é nefrotóxico, hepatotóxico, miotóxico e neurotóxico. TRATAMENTO: Além de visar a diminuição da absorção e estimular a excreção do paraquat absorvido, o tratamento da intoxicação atualmente é baseado em medidas que diminuam o estresse oxidativo utilizando substâncias antioxidantes e, conseqüentemente, revertam o quadro toxicológico instalado, especialmente o pulmonar. MÉTODOS DIAGNÓSTICOS: Entre as metodologias quantitativas disponíveis, os métodos cromatográficos são os mais relatados para materiais biológicos. Porém, a eletroforese capilar e os imunoensaios podem ser utilizados. Os imunoensaios destacam-se pela praticidade laboratorial, pois os cromatográficos e eletroforéticos não são encontrados comumente em laboratórios hospitalares. Por outro lado, uma reação simples e rápida de caracterização urinária com ditionito de sódio é muito realizada, pois é preditiva na suspeita de intoxicações agudas. CONCLUSÃO: Diante do alto potencial de morbimortalidade nas intoxicações por paraquat, a reversão dos danos pulmonares com uso de antioxidantes vem sendo muito estudada, porém não há o estabelecimento de um antídoto específico. No diagnóstico laboratorial, métodos cromatográficos, eletroforéticos e imunológicos são usados para quantificá-lo, contudo a reação urinária com ditionito ainda é valiosa na rotina da toxicologia clínica.

INTRODUCTION: Paraquat is a herbicide widely used in agriculture. It is a very toxic product, fatally poisoning mainly by the lack of an efficient antidote to revert the clinical state. FISIOPATHOLOGY: Toxicological effects are decurrent of oxidative stress. The most important target organ is the lung, which can display edema, hemorrhage, interstitial inflammation and fibroses, culminating in serious respiratory failure and death. Moreover, it is nephrotoxic, hepatotoxic, miotoxic and neurotoxic. TREATMENT: Besides aiming the decrease of absorption and stimulating the excretion of absorbed paraquat, the poisoning treatment nowadays is based on measures that decrease oxidative stress using antioxidants, consequently reverting clinical state, mainly the pulmonary. Diagnostic methods: Among the available quantitative methods, the chromatographic are the most reported ones for biological samples. However, capillary electrophoresis and immunoassay methods can be used. Immunoassays stand out for being typically found in hospital laboratories, while chromatographic and electrophoretic methods are not. On the other hand, a simple and fast urinary reaction with sodium dithionite is very utilized because it is predictive in acute poisoning suspect. CONCLUSION: In the presence of high morbimortality potential in paraquat intoxications, the reversion of pulmonary toxicity with antioxidants is extensively studied, but a specific antidote is not established. In laboratorial diagnostic, chromatographic, electrophoretic and immunologic techniques are applied to paraquat quantification, although in clinical toxicology the sodium dithionite reaction is still significant.

INTRODUÇÃO: A vitamina B12 é hidrossolúvel, não-sintetizada pelo organismo humano, presente em alimentos de origem animal. Sua deficiência é muito freqüente entre idosos, vegetarianos e indivíduos que adotam baixa dieta protéica ou apresentam problemas de absorção gastrintestinal. FISIOPATOLOGIA: A deficiência de vitamina B12 leva a transtornos hematológicos, neurológicos e cardiovasculares, principalmente, por interferir no metabolismo da homocisteína (Hcy) e nas reações de metilação do organismo. Muitas vezes a deficiência pode permanecer assintomática por longos períodos, desencadeando uma deficiência crônica que, se mantida, pode levar a manifestações neurológicas irreversíveis. METODOLOGIAS: Metodologias eficientes que permitam um diagnóstico precoce são imprescindíveis. Porém um método considerado padrão-ouro ainda não é consensual. A dosagem sérica de vitamina B12 sofre algumas restrições pelos problemas de sensibilidade e especificidade, podendo ocorrer sintomas de deficiência mesmo com vitamina B12 sérica dentro dos níveis normais ou, de outro modo, ocorrendo baixos níveis de vitamina B12 sérica sem, contudo, apresentar baixos níveis da fração de vitamina realmente disponível para as células e sem apresentar sintomatologia. Novas alternativas vêm surgindo, como a dosagem de transcobalamina II (Tc II), a única fração de vitamina B12 disponível para as células, ou a dosagem de ácido metilmalônico (MMA) e Hcy, metabólitos que aumentam quando ocorre diminuição de vitamina B12 intracelular. Estes testes apresentam algumas vantagens, mas também limitações importantes para uso rotineiro. CONCLUSÃO: Em casos subclínicos, um diagnóstico correto e precoce representa ainda um desafio, e futuros estudos são necessários para definir um método padrão para diagnóstico laboratorial da deficiência de vitamina B12.

INTRODUCTION: The vitamin B12 is a water soluble vitamin, not synthetized by humans organisms, found in foods of animal origin. Its deficiency is very frequent among old people, vegetarians, subjects who use a low protein diet, or who present gastrointestinal absorption failure. PHYSIOPATHOLOGY: The vitamin B12 deficiency leads to hematologic, neurophatologic and cardiovascular disorders, mainly by interfering in the homocysteine (Hcy) metabolism and in the methylation reactions of organism. Often, the deficiency can remain without symptoms for long time, leading to a chronic deficiency that, if not treated, may yield irreversible neurologic manifestations. METHODOLOGY: Efficient methodologies that allow the early diagnosis are essential. However, a gold standard method is not consensus yet. The vitamin B12 serum measurement presents some restrictions for problems of sensitivity and specificity, being able to occur deficiency’s symptoms even the serum vitamin B12 being in normal range or, in another way, occurring low levels of serum vitamin B12 without, however, showing low levels of vitamin B12 fraction really available for the cells and without showing symptoms. New alternatives come appearing, as the transcobalamin II measurement, the only vitamin B12 fraction available for the cells or the methylmalonic acid and Hcy measurement, metabolites that increase when intracellular vitamin B12 decreases. These tests present some advantages, but also important limitations for use in the routine. CONCLUSION: In the sub clinical cases, a correct and early diagnosis represents still a challenge and further studies are needed to define the best method for routine laboratorial diagnosis of vitamin B12 deficiency.