Determination of the whitening effect of toothpastes on human teeth / Determinación del efecto blanqueador de los dentífricos en dientes humanos

Abstract The desire of individuals to have whiter teeth increases the interest in tooth whitening products. Our aim was to in vitro study the whitening effect of hydrogen peroxide, blue covarine and active charcoal containing whitening toothpastes on human teeth. A total of 40 extracted human incisor teeth were used in the study. To measure the whitening effect of toothpastes, the teeth were divided into four subgroups and placed in the phantom tooth jaw model. Then, daily brushing was done with an electric toothbrush. The colors of the teeth were measured initially using the spectrophotometer (single point and bleached shade mode) and at the end of 7th, 14th and 28th days. Whitening effectiveness of toothpastes were studied according to CIEDE2000 formula (ΔE00) and shade guide units (SGU). One- way analysis of variance (ANOVA) and Tukey test were used in the statistical analysis of the data. (p0.05). Blue covarine containing toothpaste had statistically the lowest whitening effect (p<0.05). All toothpastes showed a whitening effect on the teeth after 7 days of use. Activated charcoal containing toothpaste showed more whitening effect after 28 days of use than hydrogen peroxide, blue covarine and traditional toothpaste.

Resumen El deseo de los individuos de tener unos dientes más blancos aumenta el interés por los productos de blanqueamiento dental. Nuestro objetivo fue estudiar el efecto blanqueador de las pastas dentales blanqueadoras que contienen peróxido de hidrógeno, covarina azul y carbón activo en dientes humanos in vitro. En el estudio se utilizaron un total de 40 dientes incisivos humanos extraídos. Para medir el efecto blanqueador de los dentífricos, los dientes se dividieron en cuatro subgrupos y se colocaron en el modelo de diente fantasma en mandíbula. A continuación, se realizó un cepillado diario con un cepillo eléctrico. El color de los dientes se midió inicialmente con un espectrofotómetro (modo de punto único y tono blanqueado) y al final de los días 7, 14 y 28. Se estudió la eficacia blanqueadora de los dentífricos según la fórmula CIEDE2000 (ΔE00) y las unidades de guía de color (SGU). En el análisis estadístico de los datos se utilizó el análisis de varianza de una vía (ANOVA) y la prueba de Tukey. (p0,05). El dentífrico que contiene covarina azul tuvo estadísticamente el menor efecto blanqueador (p<0,05). Todos los dentífricos mostraron un efecto blanqueador en los dientes después de 7 días de uso. Los dentífricos con carbón activado mostraron un mayor efecto blanqueador tras 28 días de uso que el peróxido de hidrógeno, la covarina azul y el dentífrico tradicional.

The anticonvulsant effects of Ducrosia anethifolia (Boiss) essential oil are produced by its main component alpha-pinene in rats / Os efeitos anticonvulsivantes do óleo essencial de Ducrosia anethifolia (Boiss) são realizados pelo seu principal componente alfa-pineno em ratos

ABSTRACT Ducrosia anethifolia has been recommended as a remedy for neurological disorders. However, the anticonvulsant effects of D. anethifolia essential oil (DAEO) and its major constituent α-pinene have not yet been clarified. Methods: A rat model of pentylenetetrazole (PTZ)-induced convulsions was used. Oxidant and antioxidant parameters were assayed in the temporal lobe. Results: The data showed that DAEO (50, 100 and 200 mg/kg, i.p.) and α-pinene (0.2 and 0.4 mg/kg i.p.) delayed the initiation time, and reduced the duration of myoclonic and tonic-clonic seizures following PTZ injection. The PTZ produced oxidative stress so that malondialdehyde and hydrogen peroxide levels were increased and catalase and peroxidase activity decreased. Pretreatment with DAEO and α-pinene significantly inhibited the above-mentioned enzymatic changes in PTZ-treated animals. Conclusion: The results suggest that α-pinene, at teast in part, was responsible for the induction of the anticonvulsant and antioxidant effects of DAEO in rats.

RESUMO A Ducrosia anethifolia tem sido recomendada como remédio para os distúrbios neurológicos. No entanto, os efeitos anticonvulsivantes do óleo essencial de Ducrosia anethifolia (DAEO) e do seu principal constituinte atfa-pineno (α-pineno) ainda não foram clarificados. Métodos: Foi utilizado um modelo de rato de convulsões induzidas por pentilenotetrazol (PTZ). Os parâmetros oxidante e antioxidante foram ensaiados no lobo temporal do cérebro. Resultados: Os dados mostraram que DAEO (50, 100 e 200 mg / kg, i.p.) e α-pineno (0,2 e 0,4 mg / kg i.p.) retardaram o tempo de iniciação e reduziram a duração das crises mioclônicas e tônico-clônicas após a injeção de PTZ. O PTZ produziu estresse oxidativo, de modo que os níveis de malondialdeído (MDA) e de peróxido de hidrogênio aumentaram e a atividade da catalase e da peroxidase diminuiu. O pré-tratamento com DAEO e α-pineno inibiu significativamente as alterações enzimáticas mencionadas em animais tratados com PTZ. Conclusão: O resultado sugere que α-pineno, peto menos em parte, é responsável peta indução dos efeitos anticonvulsivantes e antioxidantes da DAEO em ratos.

Eixo XPC-P53-H202 e disfunção mitocondrial: qual é o fator central? / XPC-p53-H2O2 axis and mitochondrial disfunction: Which is the key player

A ausência de XPC, uma proteína canonicamente envolvida em reparo de DNA por excisão de nucleotídeos, está associada a vários fenótipos característicos de disfunção mitocondrial como o desequilíbrio entre os complexos da cadeia transportadora de elétrons (CTE), redução no consumo de oxigênio, maior produção de peróxido de hidrogênio, e maior sensibilidade a agentes que causam estresse mitocondrial. Contudo, uma descrição mecanística da relação entre deficiência de XPC e disfunção mitocondrial ainda não está bem estabelecida. Aqui mostramos que a deficiência de XPC está associada ao aumento na expressão do supressor de tumor p53. Essa alteração é acompanhada pelo aumento da expressão de diversas proteínas que participam em importantes funções mitocondriais. A inibição de p53 reverte a superexpressão de algumas dessas proteínas. O tratamento com o inibidor do Complexo III da CTE antimicina A induz aumento da expressão de p53 de forma mais acentuada na linhagem Xpc-/-, enquanto o tratamento com o antioxidante N-acetilcisteína diminue a produção basal de H2O2, expressão de p53 e sensibilidade aumentada ao tratamento com antimicina A. Em conjunto, nossos resultados suportam a hipótese de que o aumento da produção de H2O2 em células Xpc-/- tem um papel causal na regulação da expressão de p53 e na disfunção mitocondrial

Although XPC has been initially implicated in the nucleotide excision DNA repair pathway, its deficiency is associated with mitochondrial dysfunction, including unbalanced electron transport chain (ETC) activity, lower oxygen consumption, increased hydrogen peroxide production, and greater sensitivity to mitochondrial stress. However, a mechanistic understanding of the role of XPC in regulating mitochondrial function is still not well established. Here we show that XPC deficiency is associated with increased expression of the tumor suppressor p53, which is accompanied by increased expression of several proteins that participate in important mitochondrial functions. Inhibition of p53 reverses the overexpression of some of these proteins. In addition, treatment with the ETC inhibitor antimycin A induces p53 expression more robustly in the Xpc-/- cells, while treatment with the antioxidant N-acetylcysteine decreases basal H2O2 production, p53 expression and sensitivity to antimycin A treatment. Together, our results support a model in which increased H2O2 production in Xpc-/- causes upregulation of p53 expression and mitochondrial dysfunction

The antioxidative defense system is involved in the premature senescence in transgenic tobacco (Nicotiana tabacum NC89)

BACKGROUND: α-Farnesene is a volatile sesquiterpene synthesized by the plant mevalonate (MVA) pathway through the action of α-farnesene synthase. The α-farnesene synthase 1 (MdAFS1) gene was isolated from apple peel (var. white winterpearmain), and transformed into tobacco (Nicotiana tabacum NC89). The transgenic plants had faster stem elongation during vegetative growth and earlier flowering than wild type (WT). Our studies focused on the transgenic tobacco phenotype. RESULTS: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants. Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide radicals (O2._) had higher levels in transgenics compared to controls. Transgenic plants also had enhanced sensitivity to oxidative stress. The transcriptome of 8-week-old plants was studied to detect molecular changes. Differentially expressed unigene analysis showed that ubiquitin-mediated proteolysis, cell growth, and death unigenes were upregulated. Unigenes related to photosynthesis, antioxidant activity, and nitrogen metabolism were downregulated. Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage. CONCLUSIONS: The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.

Biochemical Markers of Oxidative Stress in Saudi Women with Recurrent Miscarriage

This study was undertaken to investigate the antioxidant/oxidant status in recurrent miscarriage patients. Antioxidants including glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR), reduced glutathione (GSH) and selenium (Se), as well as the oxidants hydrogen peroxide (H2O2), oxidised glutathione (GSSG) and lipid peroxidation were assayed in plasma, whole blood and placental tissue of non-pregnant women (NP), healthy pregnant women (HP), and recurrent miscarriage (RM) patients. Results indicated that all antioxidant activities and levels in plasma and whole blood of HP women were consistently moderately lower, and much more significantly lower in RM patients when both were compared to those seen in NP women (P<0.05 and P<0.001, respectively). Furthermore, whereas plasma antioxidant activities and levels were significantly lower in RM patients, those of whole blood and placental tissue were much more significantly lower when compared with HP women (P<0.001). Concurrent with these findings there were consistent increases of equal statistical significance and magnitude in the levels of all investigated oxidants assayed in all samples when compared in between subjects of the study as indicated above. Data thus illustrated a distinct shift in favor of oxidative reactions and reactive oxygen species (ROS) generation, and very significant decreases in the GSH/GSSG ratios in whole blood and placental tissue of RM patients when compared to HP and NP women (P<0.001). The above noted oxidative stress could have been a major causative factor of recurrent miscarriage.

Longterm melatonin administration alleviates paraquat mediated oxidative stress in Drosophila melanogaster / La administración de melatonina a largo plazo mitiga el estrés oxidativo mediado por paraquat en Drosophila melanogaster

We investigated the effect of melatonin (MEL) in the activities of cytosolic superoxide dismutase (SOD) and catalase as well as in the levels of H2O2 and mitochondrial malondialdehyde (MDA) in paraquat-intoxicated Drosophila melanogaster. Paraquat (40 mM) was administrated for 36 h. Three groups of flies intoxicated with paraquat were used: PQ (exposed during 36h to paraquat), PQ-MEL (exposed during 36h to paraquat and then treated with MEL [0.43 mM] for 12 days) and PQ-Control (maintained in standard corn meal for 12 days). Two additional groups without pre-intoxication with PQ were added: Control (maintained in standard corn meal) and MEL (treated with MEL for 12 days). Immediately after PQ intoxication the concentration of MDA (17.240 ± 0.554 nmoles MDA/mg protein) and H2O2 (3.313 ± 0.086 nmol hydrogen peroxide/mg protein) and the activities of SOD and catalase (419.667 ± 0.731 and 0.216 ± 0.009 Units/mg of protein, respectively) in the PQ group were significantly increased with respect to Control. After 12 days of intoxication with PQ, the PQ-Control flies showed increases in H2O2 (4.336 ± 0.108) and MDA levels (8.620 ± 0.156), and in the activities of SOD and catalase (692.570 ± 0.433 and 0.327 ± 0.003, respectively) as compared to PQ-MEL (p<0.001). Treatment with MEL extended the life span of the groups PQ-MEL and MEL when compared to their corresponding controls. Motor activity decreased significantly in PQ-Control and PQ-MEL flies, suggesting that the damage caused by PQ affected the nervous system of flies. Our findings showed that oxidative damage caused by paraquat was observed even after 12 days and that melatonin mitigates this damage.

Investigamos el efecto de la melatonina (MEL) en la actividad de la superóxido dismutasa citosólica (SOD) y la catalasa, así como en las concentraciones del H2O2 y del malondialdehido mitocondrial (MDA) en la toxicidad inducida por paraquat (PQ) en Drosophila melanogaster. El paraquat (40 mM) fue administrado durante 36h. Tres grupos de moscas se utilizaron después de la intoxicación con paraquat: PQ (expuestas a paraquat durante 36 h), PQ-MEL (expuestas durante 36 horas a PQ y luego tratadas con MEL [0,43 mM] por 12 días) y PQ-Control (mantenidas en medio estándar por 12 días). Se incluyeron dos grupos adicionales sin pre-intoxicación con PQ: Control (mantenido en medio estándar) y MEL (tratado con MEL por 12 días). Inmediatamente después de la intoxicación con PQ, las concentraciones de MDA (17,240 ± 0,554 nmol de MDA/mg de proteína), H2O2 (3,313 ± 0,086 nmol de H2O2/mg de proteína) y las actividades de la SOD y catalasa (419,667 ± 0,731 y 0,216 ± 0,009 unidades/mg de proteína, respectivamente) se incrementaron significativamente con respecto al Control. Doce días después de la intoxicación con PQ, las moscas PQ-Control mostraron un aumento en la concentración de H2O2 (4,336 ± 0,108), de los niveles de MDA (8,620 ± 0,156) y en las actividades de la SOD y la catalasa (692,570 ± 0,433 y 0,327 ± 0,003, respectivamente) en comparación con el grupo PQ-MEL (p<0,001). El tratamiento con MEL extendió el tiempo de vida de los grupos PQ-MEL y MEL en comparación con sus correspondientes controles. La actividad motora disminuyó significativamente en las moscas de los grupos PQ-Control y PQ-MEL, lo que sugiere que el PQ afectó el sistema nervioso de las moscas. Nuestros hallazgos demostraron que el daño oxidativo causado por paraquat en las moscas fue observado aún después de 12 días de intoxicadas y que la melatonina logró mitigar este daño.

Avaliação do risco de potencial ecotoxicológico de resíduos de 17? estradiol obtidos pós-processo oxidativo a base de peróxido de hidrogênio destinados a remoção deste hormônio / Assessment of potential ecotoxicological risk from products of estradiol 17? after process of oxidation with hydrogen peroxide for environmental removal of this hormone

The increasing disposal of medicines into the environment has increased concern about the possible environmental impact of such actions, in both the medium and long term. Estrogens have been found in soil, surface water and groundwater. The aim of this study was to assess the ecotoxicity of chemical residues originating from in situ oxidation of 17β estradiol with hydrogen peroxide, a process of chemical remediation which is used to remove these hormones in acetone solution, at various pHs. Analyses were carried out by high resolution gas chromatography and a bioassay in which the single-cell species Euglena gracilis was the test organism. The results were obtained by comparing analyses done before and after the AOP (advanced oxidation process). It was observed that at pH 5.0, with a treatment time of 20 minutes, there was a good yield, but with some change in the behavior of the test organism. With a pH of 7.0, with 20 minutes time, the yield was low but there was no demonstration of ecotoxicological activity...

Com o crescente descarte de medicamentos no meio ambiente, observa-se o aumento da preocupação com o impacto ambiental que tal ação pode acarretar, tanto a médio como em longo prazo. Os estrogênios vêm sendo encontrados no solo, em águas superficiais e subterrâneas. O objetivo deste estudo foi avaliar a ecotoxicidade dos resíduos químicos originados a partir da oxidação do 17? estradiol, via peróxido de hidrogênio, em um processo destinado à remoção química destes hormônios em solução de acetona, e em diferentes pHs. As análises foram feitas utilizando cromatografia gasosa de alta resolução e bioteste com algas do gênero Euglenas gracillis. Os resultados foram baseados nas comparações de análises pré-processo oxidativo avançado (POA) e pós POA. Observou-se que os resultados obtidos na condição de pH 5,0, com tempo de 20 minutos, apresentou um bom rendimento, porém com mudança de comportamento dos bioindicadores. Em pH 7,0, com tempo de 20 minutos, o rendimento foi menor, porém não houve demonstração de atividade ecotoxicológica...

Avaliação da microdureza e rugosidade superficial de uma resina composta submetida ao clareamento com peróxido de hidrogênio a 35% / Evaluation of microhardness and surface roughness of a composite resin under 35% hydrogen peroxide bleaching

Objetivo - Avaliar a microdureza e rugosidade superficial de uma resina composta microhíbrida à base de silorano, submetida ao clareamento imediato com peróxido de hidrogênio a 35%, autocatalisado, contendo cálcio. Métodos - Foram confeccionados 30 corpos de prova, divididos em 3 grupos experimentais: Grupo 1 (n=10): resina composta sem tratamento clareador; Grupo 2 (n=10): resina composta submetida a duas sessões de clareamento imediato com peróxido de hidrogênio a 35%; Grupo 3 (n=10): resina composta submetida a duas sessões de clareamento imediato com peróxido de hidrogênio a 35% com cálcio e armazenadas por 7 dias em saliva artificial a 37ºC. Foram realizados testes de rugosidade e microdureza para todos os grupos. Resultados - Os dados foram avaliados por análises de variância ao nível de significância de 5%, complementadas pelo teste de Tukey. Não houve diferença significativa entre os grupos quanto à rugosidade (p=0,481), ainda que a média do controle tenha sido maior do que dos outros grupos. Por outro lado, houve diferença significativa entre grupos quanto à microdureza (p=0,007). Os grupos G1 e G2 apresentaram médias de microdureza equivalentes e significativamente maiores do que a média do grupo G3. Conclusão - Pode-se concluir que, após o clareamento com peróxido de hidrogênio a 35% contendo cálcio, a rugosidade superficial da resina não se alterou e a microdureza diminuiu após uma semana de armazenamento em saliva artificial.

Objective - To evaluate the microhardness and surface roughness of a resin-based microhybrid silorano, subjected to bleaching with hydrogen peroxide 35%, self-catalyzed, containing calcium. Methods - There was prepared 30 specimens, divided into three groups: Group 1 (n = 10): composite without bleaching treatment, Group 2 (n = 10): composite subjected to two sessions immediately bleaching with hydrogen peroxide 35%, Group 3 (n = 10): composite subjected to two sessions immediately bleaching with hydrogen peroxide to 35% with calcium and stored for 7 days at 37°C in artificial saliva. Tests of roughness and hardness were performed for all groups. Results - Data were evaluated by analysis of variance at a significance level of 5%, complemented by the Tukey test. There was no significant difference between groups in terms of roughness (p = 0.481), although the average of the control was higher than the other groups. On the other hand, significant differences between groups in terms of microhardness (p = 0.007) were observed. The groups G1 and G2 showed average microhardness equivalent and significantly higher than the average of the group G3. Conclusion - It can be concluded that, after bleaching with hydrogen peroxide containing 35% calcium, the surface roughness of the resin did not change and microhardness decreased after one week storage in artificial saliva.

Produção de peróxido de hidrogênio e atividade de enzimas antioxidantes de macrófagos peritoneais em resposta ao BCG (Bacilo de Calmette-guérin) em modelo murínico de desnutrição proteico-energética / Hydrogen peroxide production and activity of antioxidant enzymes of peritoneal macrophages in response to BCG (Bacillus Calmette-guérin) in a murine model of protein-energy malnutrition

units of BCG (Bacillus Calmette-guérin) and after 7 days they were used in the experiments. We evaluated the complete blood count, peritoneal cellularity and hydrogen peroxide production, besides the activities of glutathione peroxidase, superoxide dismutase and catalase in peritoneal macrophages stimulated with BCG. Malnourished animals presented anemia, leukopenia and severe reduction of peritoneal cellularity. The production of hydrogen peroxide and the activity of glutathione peroxidase, superoxide dismutase and catalase were found to be significantly lower in macrophages from malnourished animals. These findings suggest that malnourished animals present a deficient response to BCG. These findings may be partly responsible for a decrease in the bactericidal and fungicidal activities observed in the malnourished mice. These data lead us to infer that the nutritional status interferes with the activation of macrophages and with the capacity tomount an immune response.Protein-energy malnutrition (PEM) modifies resistance to infection, impairing a number of physiological processes, changing specific and nonspecific immune responses. Macrophages, which are directly involved in several aspects of immunity, may have their functions altered in the malnourishment condition, possibly playing a significant role in the immune deficiency observed in malnourished individuals. Two-month-old male Swiss mice were induced to PEM with a low-protein diet containing 4% protein as compared to 20% protein in the control diet. When the experimental group had lost about 20% of their original body weight the animals from both groups received intraperitoneal injections of 10

unidades de BCG (Bacilo de Calmetteguérin), por vía intraperitoneal, y después de 7 días los animales fueron sacrificados para evaluación de diversos índices: hemograma, celularidad peritoneal, la producción deperóxido de hidrógeno y las actividades glutatión peroxidada, superóxido dismutasa, y catalasa en macrófagos peritonea les estimulados con BCG. Los animales subalimentados presentaron anemia, leucopenia y reducción de la celularidad peritoneal. La producción de peróxido de hidrógeno y la actividad de las enzimas glutatión peroxidada, superóxido dismutasa, y catalasa fue más baja en macrófagos de animales desnutridos. Los resultados sugieren que los ratos desnutridos presentan una respuesta deficiente a BCG lo que explica en parte la disminución de la actividad bactericida y fungicida observada en animales desnutridos. Estos resultados permiten deducir que el estado nutricional interfiere en la actividad de los macrófagos y en su capacidadde respuesta inmunológica.La desnutrición proteico-energética modifica la resistencia a infecciones, alterando diversos procesos fisiológicos, mudando la capacidad de respuesta inmune, específica y no específica. Los macrófagos, células implicadas directamente en varios aspectos de la inmunidad, pueden tener sus funciones alteradas en condiciones de desnutrición desempeñando posiblemente un papel significativo en la deficiencia inmune observada en individuos desnutridos. En este estudio se utilizaron ratos Swiss machos, de 2 meses de edad, en los cuales fue inducida desnutrición proteico-energética por mediode una dieta que contenía 4% de proteína. El grupo control recibió una dieta estándar con 20% de proteína. Cuando el grupo experimental presentó una pérdida de 20% desu peso corporal original, se le administraron 10

unidades de BCG (Bacilo de Calmetteguérin) e após 7 dias foram sacrificados e utilizados nos experimentos. Avaliamos o hemograma, a celularidade peritoneal assim como a produção de peróxido de hidrogênio e a atividade da glutationa peroxidase, superóxido dismutase e catalase em resposta ao BCG em macrófagos peritoneais. Os animais desnutridos apresentaram anemia, leucopenia e a redução severa da celularidade peritoneal. A produção de peróxido de hidrogênio e a atividade das enzimas glutationa peroxidase, super óxido dismutase e catalase foi significativamente menor nos macrófagos de animais desnutridos. Estes resultados sugerem que os animais desnutridos apresentem uma resposta deficiente ao BCG, e que, em parte, podem explicar a diminuição nas atividades bactericidas e fungicidas observadas em animais desnutridos. Estes dados permitem deduzir que o estado nutricional interfere na ativação dos macrófagos e na sua capacidadede resposta imune.A desnutrição proteico-energética (DPE) altera a capacidade de resistência à infecção, alterando diversos processos fisiológicos, mudando a capacidade de respostas imunes específicas e não específicas. Os macrófagos são células envolvidas diretamente em diversos aspectos da imunidade, podem ter suas funções alteradas em condições de desnutrição desempenhando, possivelmente, um papel significativo na imunodeficiência observada nesses indivíduos. Camundongos Swiss, machos, de dois meses de idade, foram induzidos a DPE com uma dieta contendo baixa concentração deproteína (4%) em comparação à dieta controle (20%). Quando o grupo experimental perdeu aproximadamente 20% de seu peso corpóreo original, estes foram considerados aptos aos experimentos. Animais de ambos os grupos receberam injeção intraperitoneal contendo10

Función del peróxido de hidrógeno en el vitíligo / Function of hydrogen peroxide in cases of vitiligo

El vitíligo es un desorden de la pigmentación que tiene una incidencia entre el 0,5 y 3 por ciento en la población mundial. Se caracteriza por una despigmentación de la piel provocada por la presencia de melanocitos afuncionales en la epidermis. Cuando ocurren eventos desencadenantes del estrés oxidativo, las concentraciones de peróxido de hidrógeno se incrementan ostensiblemente en melanocitos y queratinocitos. Los queratinocitos actúan como fuente de especies reactivas de oxígeno y transfieren a los melanocitos grandes cantidades de peróxido de hidrógeno. Evidencias experimentales han demostrado que como consecuencias de las altas concentraciones de peróxido de hidrógeno en la epidermis de pacientes con vitíligo, se afectan las concentraciones de butirilcolinesterasa y acetilcolineterasa, la actividad enzimática en el ciclo de las 6HB4, los péptidos derivados de proopiomelanocortinas y las proteínas del estrés entre otros muchos eventos. Todos estos eventos, tras una situación precipitante sobre un individuo genéticamente predispuesto, podrían promover cambios en la pigmentación de la piel que lo conducen, en última instancia, al vitíligo

Vitiligo is a pigmentation disorder with an incidence between the 0,5 and the 3 percent at worldwide. It is characterized by a skin depigmentation provoked by presence of dysfunctional melanocytes in epidermis. When oxidative stress triggering events are present, hydrogen peroxide concentrations clearly increase in the melanocytes and keratinocytes. The keratinocytes act as a source of oxygen and transfer to melanocytes high amounts of hydrogen peroxide. Experimental evidences have demonstrated that due to the high hydrogen peroxide concentrations in epidermis of vitiligo patients affecting the concentrations of butyryl-cholinesterase and the acetylcholinesterase, the enzymatic activity in 6HB4 cycle, propiomelanocortins and stress protein among many events. All these events after a hasty situation on a genetically predisposing subject could to promote changes in skin pigmentation that as a last resort leading to vitiligo

Chronic treatment with ethanolic extract of the leavesof Azadirachta indica ameliorates lesions of pancreatic islets in streptozotocin diabetes / Tratamiento crónico con extracto etanólico de hojas de Azadirachta indica disminuye las lesiones de los islotes pancreáticos en diabetes por estreptozotocina

Botanical drugs are complementary therapies in the management of diabetes mellitus. In this work, we studied the effects of chronic treatment of diabetic rats with A. indica (neem) on blood glucose, pancreatic islet histopathology, and oxidative status of the pancreas. Fifty-four Wistar rats (5-8 weeks old) were randomly assigned to 5 treatment groups. Hyperglycemia was induced in 34 fasted rats with a single i.p. injection of STZ (70 mg/kg bw/d). Ethanolic extract of A. indica leaves (500 mg/kg bw/d) was given orally to diabetic rats (n=12) for 50d. Glibenclamide was given (p.o) at 600 µg/ kg bw/d. In each group, blood glucose, islet histopathology, and pancreatic oxidative status, were assessed. All hyperglycemic rats in the neem-treated group had become normoglycemic at the end of week 2. By 50d, the number of viable b cells was highest in the neem-treated diabetic rats (compared with the diabetic and glibenclamide groups). Similarly, islet histology showed marked improvement in this group, in addition to improved oxidative stress. Our findings confirmed the hypoglycemic effect of neem. Besides, the improved islet morphology and oxidative status in neem-treated diabetic rats suggest the potential of this herb at improving lesions of the pancreatic islet in diabetes mellitus.

Los medicamentos a base de plantas son terapias complementarias en el manejo de la diabetes mellitus. En este trabajo se estudiaron los efectos del tratamiento crónico de ratas diabéticas con A. indica (Neem) sobre la glucosa de la sangre, la histopatología de los islotes pancreáticos, y el estado oxidativo del páncreas. Cincuenta y cuatro ratas Wistar (5-8 semanas de edad) fueron asignadas aleatoriamente a 5 grupos de tratamiento. La hiperglucemia fue inducida en 34 ratas en ayunas con una única inyección IP de STZ (70 mg/kg peso corporal/d). El extracto etanólico de hojas de A. indica (500 mg/kg de peso corporal/día) fue administrado por vía oral a ratas diabéticas (n=12) por 50d. Glibenclamida fue dada (PO) a 600 mg/kg peso corporal/d. En cada grupo, la glucosa en la sangre, la histopatología de los islotes, y el estado oxidativo de páncreas, se evaluaron. Todas las ratas de hiperglucemia en el grupo tratado con el Neem se habían convertido en normoglucémicas al final de la semana 2. Por 50d, el número de células b viables fue mayor en el Neem ratas tratadas con diabetes (en comparación con los grupos de diabéticos y glibenclamida). Del mismo modo, la histología de los islotes mostró una notable mejoría en este grupo, además de mejorar el estrés oxidativo. Nuestros resultados confirman el efecto hipoglucemiante de Neem. Además, la mejora de la morfología de los islotes y el estado de oxidación en el neem tratados con ratas diabéticas sugieren el potencial de esta hierba en la mejora de las lesiones de los islotes pancreáticos en la diabetes mellitus.

Diseño y evaluación de un equipo para obtener aire espirado condensado / Design and evaluation of a device for collecting exhaled breath condensate

El análisis de muestras de aire espirado condensado ha cobrado gran relevancia en los últimos años como método no invasivo de estudio de la fisiología y las enfermedades de origen pulmonar. En el presente trabajo se describe un equipo para tomar muestras de aire espirado condensado de bajo costo, fácil de fabricar, de transportar al terreno y que permite tomar muestras en forma simultánea. La concentración de metabolitos relativos a procesos inflamatorios y al daño oxidativo (pH, peróxido de hidrógeno y nitrito) de muestras de aire espirado condensado obtenido con este equipo son comparables a los reportados con otros previamente.

In recent years, the analysis of exhaled breath condensate samples has been given great weight as a noninvasive methodology of studying physiology and lung diseases. The present study describes a device for measuring exhaled breath condensate that is affordable, easily constructed, portable and suitable for use in the field, as well as allowing the collection of simultaneous samples. The results obtained with this device in terms of the concentrations of pH, peroxide oxide and nitrite, metabolites related to inflammatory and oxidative damage, in exhaled breath condensate samples are comparable to those obtained with other devices previously described.

Cytotoxicity evaluation of four endodontic sealers

This study evaluated in vitro the cytotoxicity of four root canal sealers (Topseal, EndoRez, TubliSeal and Kerr Pulp Canal Sealer E.W.T.) and their effects on reactive oxygen/nitrogen intermediate induction by mouse peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 mL 10 mM phosphate-buffered saline, washed twice and resuspended (106 cells/mL) in appropriate medium for each test. Cytotoxicity was determined by the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the peroxidase-dependent oxidation of phenol red and Griess reaction, respectively. Sealer suspensions were obtained in two different concentrations from each material: 18 mg/mL and 9 mg/mL, established according to compatibility parameters following MTT assay. Comparing the sealers, H2O2 release at concentrations of 9 mg/mL and 18 mg/mL was similar: Topseal > positive control (medium + cells + 5 mg/mL zimozan solution) > EndoRez > TubliSeal > Kerr Pulp E.W.T. > negative control (medium + cells). NO release at concentration of 9 mg/mL was: positive control (medium + cells + 10 µg/mL LPS solution) > Topseal > Kerr Pulp E.W.T. > TubliSeal = EndoRez > negative control (medium + cells); at concentration of 18 mg/mL was: positive control > Topseal > Kerr Pulp E.W.T > TubliSeal > EndoRez > negative control. Based on the results, it may be concluded that Topseal presented the highest cytotoxicity among the tested sealers, releasing higher concentrations of NO and H2O2 in macrophage culture.

Este estudo avaliou in vitro a citotoxicidade de quatro cimentos obturadores (Topseal, EndoRez, TubliSeal e Kerr Pulp Canal Sealer E.W.T) e seus efeitos na liberação de reativos intermediários do oxigênio e do nitrogênio em cultura de macrófagos peritoniais de ratos.Tioglicolato foi utlizado para se obter células peritoneias de camundongos. A cavidade peritoneal foi irrigada com 5 mL de solução salina 10 mM. As células foram lavadas duas vezes e foi feita uma suspensão (106 células/mL) em meio apropriado para cada um dos testes. A citotoxicidade dos cimentos foi determinada pela presença de peróxido de hidrogênio (H2O2) e óxido nítrico (NO) pela oxidação peroxidase-dependente do vermelho fenol e pela reação de Griess, respectivamente. Suspensões de cimento foram obtidas em duas diferentes concentrações para cada material: 18 mg/mL e 9 mg/mL, estabelecidas previamente pelo teste de viabilidade celular MTT. Comparando os cimentos, a liberação de H2O2 foi similar nas duas concentrações: Topseal > controle positivo (meio + células + Zimozan a 5mg/mL ) > EndoRez > TubliSeal > Kerr Pulp E.W.T. > controle negativo (meio + células). A liberação de NO na concentração de 9 mg/mL foi: de 9 mg/mL foi: controle positivo (meio + células + solução de LPS a 10 »g/mL) > Topseal > Kerr Pulp E.W.T. > TubliSeal = EndoRez > controle negativo (meio + células); e na concentração de 18 mg/mL; e na concentração de 18 mg/mL: controle positivo > Topseal > Kerr Pulp E.W.T > TubliSeal > EndoRez > controle negativo. Baseado nos resultados, pode-se concluir que o Topseal apresentou a maior citotoxicidade dentre os cimentos avaliados, liberando as mais altas concentrações de NO e H2O2 em cultura de macrófagos.

Effect of the essential oil of Achillea millefolium L. in the production of hydrogen peroxide and tumor necrosis factor-"ALPHA" in murine macrophages

Macrophages release more than one hundred compounds into the extracellular environment. Among these, there are cytokines and intermediate oxigen compounds, such as TNF-"ALPHA" and 'H POT. 2''O POT. 2'. We evaluated the effect of the crude essential oil of Achillea millefolium L. (Asteraceae) by determining hydrogen peroxide ('H POT. 2''O POT. 2') and tumor necrosis factor-a (TNF-"ALPHA") release in cultures of peritoneal macrophages cells from Swiss mice. Commercial azulene was also tested for comparison with the essential oil. The macrophages viability in the presence of the oil was analyzed and dilutions of 1:100 and 1:200 showed the best results. A mild production of 'H POT. 2''O POT. 2' and a moderate liberation of TNF-"ALPHA" were observed...

Cytotoxicity of yellow sand in lung epithelial cells.

The present study was carried out to observe the cytotoxicity of yellow sand in comparison with silica and titanium dioxide in a rat alveolar type II cell line (RLE-6TN). Yellow sand (China Loess) was obtained from the loess layer in the Gunsu Province of China. The mean particle diameter of yellow sand was about 0.003 +/- 0.001 mm. Major elements of yellow sand were Si(27.7 +/- 0.6%), Al(6.01 +/- 0.17%), and Ca(5.83 +/- 0.23%) in that order. Silica and yellow sand significantly decreased cell viability and increased [Ca2+]i. All three particles increased the generation of H2O2. TiO2 did not change Fenton activity, while silica induced a slight increase of Fenton activity. In contrast, yellow sand induced a significant increase of Fenton activity. Silica, yellow sand and TiO2 induced significant nitrite formations in RLE-6TN cells. Silica showed the highest increase in nitrite formation, while yellow sand induced the least formation of nitrite. Silica and yellow sand increased the release of TNF-a. Based on these results, we suggest that yellow sand can induce cytotoxicity in RLE-6TN cells and reactive oxygen species, Fenton activity and reactive nitrogen species might be involved in this toxicity.

Sistema enzimático gerador de peróxido de hidrogênio: NADPH oxidase na tireóide humana / Enzimatic system generator of hydrogen peroxide: NADPH oxidase in human thyroid

No presente estudo avaliamos a atividade geradora de peróxido de hidrogênio (H 2 O 2 ) em frações particuladas de tireóides suínas e humanas. Inicialmente, analisamos as propriedades bioquímicas da NADPH-oxidase - enzima geradora de H 2 O 2 - localizada na membrana apical da célula tireóidea suína. Nossos resultados demonstram que a atividade geradora de H 2 O 2 na tireóide suína ocorre, principalmente, na fração de membrana apical tireóidea (P 3.000g). Entretanto, no P 3.000g a enzima NADPH-oxidase é apenas parcialmente cálcio-dependente, ao contrário do que acontece em frações purificadas de membrana tireóidea suína, nas quais a enzima é completamente dependente de cálcio, conforme estudos anteriores. Nossos resultados confirmam os previamente descritos para a NADPH oxidase tireóidea suína. Em tecidos tireóideos humanos, a geração de H 2 O 2 ocorreu, tanto na fração microsomal (P 100.000g) quanto na fração de membrana apical (P 3.000g). Nossos dados revelam ainda que a NADPH-oxidase humana é completamente cálcio-dependente, ativada por altas concentrações de fosfato e parece ser tão ativa na glândula humana quanto na suína. Além disto, a enzima humana é dependente de adenina-flavina-dinucleotídeo (FAD) no meio de reação, ou seja, parece ser uma flavoproteína, assim como a proteína suína.

Increased exhalation of hydrogen peroxide in healthy subjects following cigarette consumption

CONTEXT: Increased hydrogen peroxide has been described in the expired breath condensate (H2O2-E) of several lung conditions, such as acute respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. This technique has been advocated as being a simple method for documenting airway inflammation. OBJECTIVE: To evaluate H2O2-E in healthy cigarette smokers, and to determine the acute effects of the consumption of one cigarette on H2O2-E levels. TYPE OF STUDY: Prospective, controlled trial. SETTING: A pulmonary function laboratory in a University Hospital. PARTICIPANTS: Two groups of healthy volunteers: individuals who had never smoked (NS; n=10; 4 men; age = 30.6 Ý 6.2 years) and current cigarette smokers (S; n=12; 7 men; age = 38.7 Ý 9.8). None of the volunteers had respiratory symptoms and all showed normal spirometric tests. INTERVENTION: Expired air was collected from all volunteers through a face mask and a plastic collecting system leading into a flask with dry ice and pure ethanol. Samples from the group S were collected twice, before and half an hour after the combustion of one cigarette. MAIN MEASUREMENTS: Expired hydrogen peroxide using the Gallati and Pracht method. RESULTS: The S and NS groups showed comparable levels of H2O2-E at basal conditions [NS = 0.74 muM (DP 0.24) vs. S = 0.75 muM (DP 0.31)]. The smokers showed a significant increase in H2O2-E levels half an hour after the consumption of only one cigarette [0.75 muM (DP 0.31) vs. 0.95 muM (DP 0.22)]. CONCLUSION: The present results are consistent with the concept that smokers increase oxidative stress with elevated production of reactive oxygen species, contributing to the development of smoking-related disorders

Peróxido de hidrógeno en el humor acuoso: 1992-1997 / Hydrogen peroxide in the aqueous humor: 1992-1997

Ideas prevailing in 1991 on hydrogen peroxide in the aqueous humor are outlined. They are critically examined under the light of our finding that the method used to establish aqueous humor levels of peroxide generates itself peroxide during the short time span of the analysis. This is due to the fact that the probe used, dichlorophenol indophenol (DCPIP), spontaneously auto-oxidizes in the presence of oxygen. It was concluded then that the level of hydrogen peroxide in the aqueous humor cannot be higher than about 0.3 microM, the detection limit of the DCPIP method. It was also concluded that the statement commonly made in the literature that aqueous humor hydrogen peroxide derives from the oxidation of ascorbate, an abundant component of that fluid, is based solely on the use of the DCPIP method, and so could easily be due to a methodological artifact. The same applies to the statement that the levels of hydrogen peroxide are very high in human senile cataracts. The surprising resistance to accept the results and conclusions of our 1992 publication is documented. Finally, the content is discussed of an oral presentation made at the 1997 ARVO Annual Meeting in which an important portion of our results and conclusions was confirmed, perhaps signaling a shift towards a wider acceptance of our findings.

Análise "in vitro" da variaçäo térmica durante a utilizaçäo do hipoclorito de sódio, em diferentes concentraçöes, com peróxido de hidrogênio a 3 por cento / \"In vitro\" analysis of thermic variation during the use of sodium hypochlorite with 3 per cent hydrogen peroxide

Quantificou-se a variaçäo térmica durante a reaçäo química entre o hipoclorito de sódio nas concentraçöes de 0,5 por cento, 1,0 por cento, 1,5 por cento, 2,0 por cento, 2,5 por cento e 5,0 por cento com o peróxido de hidrogênio a 3 por cento. Observou-se a correlaçäo linear, diretamente proporcional, entre a concentraçäo das soluçöes de hipoclorito de sódio e a variaçäo térmica