Scientific use of the finite element method in Orthodontics

INTRODUCTION: The finite element method (FEM) is an engineering resource applied to calculate the stress and deformation of complex structures, and has been widely used in orthodontic research. With the advantage of being a non-invasive and accurate method that provides quantitative and detailed data on the physiological reactions possible to occur in tissues, applying the FEM can anticipate the visualization of these tissue responses through the observation of areas of stress created from applied orthodontic mechanics. OBJECTIVE: This article aims at reviewing and discussing the stages of the finite element method application and its applicability in Orthodontics. RESULTS: FEM is able to evaluate the stress distribution at the interface between periodontal ligament and alveolar bone, and the shifting trend in various types of tooth movement when using different types of orthodontic devices. Therefore, it is necessary to know specific software for this purpose. CONCLUSIONS: FEM is an important experimental method to answer questions about tooth movement, overcoming the disadvantages of other experimental methods. .

INTRODUÇÃO: o Método de Elementos Finitos (MEF) é um recurso da Engenharia empregado para calcular o estresse e a deformação de estruturas complexas, e tem sido amplamente utilizado nas pesquisas em Ortodontia. Apresenta a vantagem de ser um método não-invasivo e preciso, que fornece dados quantitativos e detalhados acerca das reações fisiológicas que podem ocorrer nos tecidos. OBJETIVO: esse artigo pretende realizar uma revisão da literatura sobre as etapas para realização do Método de Elementos Finitos, bem como de sua aplicabilidade na Ortodontia. RESULTADOS: o MEF é capaz de avaliar a distribuição do estresse na interface entre o ligamento periodontal e o osso alveolar, bem como a tendência de deslocamento em diversos tipos de movimentos dentários, quando utilizados diferentes tipos de aparelhos. Para tanto, é necessário conhecimento de softwares específicos para esse fim. CONCLUSÕES: o MEF é um importante método experimental que pode esclarecer questionamentos acerca da movimentação dentária, superando as desvantagens de outros métodos experimentais. .

Adaptation and validation of the Caregiver Burden Inventory for use with caregivers of elderly individuals / Adaptação e validação do Inventário de Sobrecarga do Cuidador para uso em cuidadores de idosos / Adaptación y validación del Inventario de Sobrecarga del Cuidador para uso en cuidadores de ancianos

OBJECTIVE: to adapt and validate the Caregiver Burden Inventory for use with caregivers of older adults in Brazil. METHOD: methodological study involving initial translation, synthesis of translations, back translation, expert committee review, pre-testing, submission of the final version to the original authors, and assessment of the inventory's psychometric properties. The inventory assesses five dimensions of caregiver burden: time-dependence, developmental, physical, social and emotional dimensions. RESULTS: a total of 120 family caregivers took part in the study. All care-receivers were older adults dependent on assistance to perform activities of daily living, and lived in the central region of the city of Porto Alegre, RS, Brasil. Cronbach's alpha value for the inventory was 0.936, and the Pearson correlation coefficient for the relationship between the scores obtained on the Caregiver Burden Inventory and the Burden Interview was 0.814. The intraclass correlation coefficient was 0.941, and the value of Student's T-test comparing test and retest scores was 0.792. CONCLUSION: the instrument presented adequate reliability and the suitability of its items and factors was confirmed in this study. .

OBJETIVO: adaptar e validar o Inventário de Sobrecarga do Cuidador para uso em cuidadores de idosos no Brasil. MÉTODO: estudo metodológico envolvendo tradução inicial, síntese das traduções, retrotradução, revisão por comitê de especialistas, pré-teste, envio da versão final para apreciação dos autores da versão original, e avaliação de suas propriedades psicométricas. O inventário avalia cinco dimensões de sobrecarga do cuidador: tempo dependente, sobrecarga à vida pessoal, física, social e emocional. RESULTADOS: participaram do estudo 120 cuidadores familiares. Todos os indivíduos sob cuidado destes cuidadores eram idosos que dependiam de assistência para realizar atividades da vida diária e residiam na região central da cidade de Porto Alegre, RS, Brasil. O valor alfa de Cronbach encontrado para o inventário foi de 0,936 e o coeficiente de correlação Pearson para a relação entre os escores obtidos no Inventário de Sobrecarga do Cuidador e na escala Burden Interview foi de 0,814. O coeficiente de correlação intraclasse foi de 0,941 e o valor do teste t de Student que comparou os escores do teste e reteste foi de 0,792. CONCLUSÃO: o instrumento apresentou confiabilidade apropriada e a adequação de seus itens e domínios foi confirmada neste estudo. .

OBJETIVO: adaptar y validar el Inventario de Sobrecarga del Cuidador para uso en cuidadores de ancianos en Brasil. MÉTODO: estudio metodológico con traducción inicial, síntesis de las traducciones, retrotraducción, revisión por comité de especialistas, preprueba, envío de la traducción final para apreciación de los autores del instrumento original, y evaluación de sus propiedades psicométricas. El Inventario evalúa cinco dominios de sobrecarga del cuidador: tiempo dependiente, sobrecarga en la vida personal, física, social y emocional. RESULTADOS: participaron del estudio 120 cuidadores familiares. Todos los individuos bajo el cuidado de estos cuidadores eran ancianos que dependían de asistencia para realizar actividades de la vida diaria y residían en la región central de la ciudad de Porto Alegre, RS, Brasil. El valor Alfa de Cronbach encontrado para el Inventario fue 0,936 y el coeficiente de correlación de Pearson para la relación entre los puntajes obtenidos entre el Inventario de Sobrecarga del Cuidador y el Burden Interview fue 0,814. El coeficiente de correlación intraclase fue 0,941 y el valor de la prueba t de Student que comparó los puntajes de la prueba y reprueba fue de 0,792. CONCLUSIÓN: el instrumento presentó confiabilidad apropiada y la adecuación de sus ítems y dominios fue confirmada en este estudio. .

Cultural adaptation, content validity and inter-rater reliability of the "STAR Skin Tear Classification System" / Adaptação cultural, validade de conteúdo e confiabilidade interobservadores do "STAR Skin Tear Classification System" / Adaptación cultural, validez de contenido y confiabilidad interobservadores del "STAR Skin Tear Classification System"

AIMS: to perform the cultural adaptation of the STAR Skin Tear Classification System into the Portuguese language and to test the content validity and inter-rater reliability of the adapted version. METHODS: methodological study with a quantitative approach. The cultural adaptation was developed in three phases: translation, evaluation by a committee of judges and back-translation. The instrument was tested regarding content validity and inter-rater reliability. RESULTS: the adapted version obtained a regular level of concordance when it was applied by nurses using photographs of friction injuries. Regarding its application in clinical practice, the adapted version obtained a moderate and statistically significant level of concordance. CONCLUSION: the study tested the content validity and inter-rater reliability of the version adapted into the Portuguese language. Its inclusion in clinical practice will enable the correct identification of this type of injury, as well as the implementation of protocols for the prevention and treatment of friction injuries. .

OBJETIVOS: realizar a adaptação cultural do STAR Skin Tear Classification System, para a língua portuguesa e testar a validade de conteúdo e a confiabilidade interobservadores da versão adaptada. MÉTODOS: estudo metodológico com abordagem quantitativa. A adaptação cultural foi desenvolvida em três fases: tradução, avaliação por comitê de juízes e retrotradução. O instrumento foi testado quanto à validade de conteúdo e confiabilidade interobservadores. RESULTADOS: a versão adaptada obteve um nível regular de concordância quando aplicada por enfermeiros em fotografias de lesões por fricção. Quando aplicada na prática clínica, a versão adaptada obteve nível moderado e estatisticamente significativo de concordância. CONCLUSÃO: o estudo atestou a validade de conteúdo e a confiabilidade interobservadores da versão adaptada para a língua portuguesa. Sua inclusão na prática clínica possibilitará a correta identificação desse tipo de lesão, além da implementação de protocolos para a prevenção e tratamento das lesões por fricção. .

OBJETIVOS: realizar la adaptación cultural del STAR Skin Tear Classification System, para el idioma portugués y comprobar la validez de contenido y la confiabilidad interobservadores de la versión adaptada. MÉTODOS: estudio metodológico con abordaje cuantitativo. La adaptación cultural fue desarrollada en tres fases: traducción, evaluación por comité de jueces y retrotraducción. El instrumento fue comprobado en lo que se refiere a su validez de contenido y confiabilidad interobservadores. RESULTADOS: la versión adaptada obtuvo un nivel regular de concordancia cuando fue aplicada por enfermeros utilizando fotografías de lesiones por fricción. Cuando fue aplicado en la práctica clínica, la versión adaptada obtuvo un nivel moderado y estadísticamente significativo de concordancia. CONCLUSIÓN: el estudio comprobó la validez de contenido y la confiabilidad interobservadores de la versión adaptada para el idioma portugués. Su inclusión en la práctica clínica posibilitará la correcta identificación de ese tipo de lesión, además de la implementación de protocolos para la prevención y tratamiento de las lesiones por fricción. .

Mitochondrial ATPase activity and membrane fluidity changes in rat liver in response to intoxication with Buckthorn (Karwinskia humboldtiana)

BACKGROUND: Karwinskia humboldtiana (Kh) is a poisonous plant of the rhamnacea family. To elucidate some of the subcellular effects of Kh toxicity, membrane fluidity and ATPase activities as hydrolytic and as proton-pumping activity were assessed in rat liver submitochondrial particles. Rats were randomly assigned into control non-treated group and groups that received 1,1.5 and 2 g/Kg body weight of dry powder of Kh fruit, respectively. Rats were euthanized at day 1 and 7 after treatment. RESULTS: Rats under Kh treatment at all dose levels tested, does not developed any neurologic symptoms. However, we detected alterations in membrane fluidity and ATPase activity. Lower dose of Kh on day 1 after treatment induced higher mitochondrial membrane fluidity than control group. This change was strongly correlated with increased ATPase activity and pH gradient driven by ATP hydrolysis. On the other hand, membrane fluidity was hardly affected on day 7 after treatment with Kh. Surprisingly, the pH gradient driven by ATPase activity was significantly higher than controls despite an diminution of the hydrolytic activity of ATPase. CONCLUSIONS: The changes in ATPase activity and pH gradient driven by ATPase activity suggest an adaptive condition whereby the fluidity of the membrane is altered.

Cell accumulation and antileishmanial effect of exogenous and endogenous protoporphyrin IX after photodynamic treatment / Acumulación celular y efecto anti- Leishmania de la protoporfirina IX exógena y endógena después del tratamiento fotodinámico

Introduction: Photodynamic therapy (PDT) using 5-aminolevulinic acid-induced protoporphyrin IX (ALA-PpIX) constitutes an interesting alternative for cutaneous leishmaniasis treatment. Objective: To evaluate the production of PpIXbased on the administration of ALA and MAL and the effect of ALA-PDTat cellular level on non-infected and infected THP-1 cells using Leishmania ( Viannia ) panamensis or Leishmania ( Leishmania ) infantum (syn Leishmania chagasi ) parasites. Materials and methods: Protoporphyrin IX (PpIX) production and mitochondrial colocalization were evaluated by confocal microscopy. Cell toxicities were evaluated after treatment with the compounds, followed by light irradiation (597-752 nm) at 2.5 J/cm 2 fluency using a colorimetric MTT assay for THP-1 cells and a standard microscopic analysis of parasites. Results were expressed as compound concentration activity against 50% of cells or parasites (CC 50 or IC 50 ). Results: ALA or MAL induced an endogenous PpIX with a red fluorescence localized mainly in the mitochondria inside human cells. ALA and MAL-PDT induced a similar range of toxicities on THP-1 cells (CC 50 0.16±0.01mM and 0.33±0.019 mM, respectively) without any apparent inhibition of intracellular parasites in the infected cells as compared to untreated controls. Exogenous PpIX-PDT was toxic to THP-1 cells (CC 50 0.00032±0.00002 mM), L. (L.) infantum (IC 50 0.003±0.0001 mM) and L. (V.) panamensis (IC 50 0.024±0.0001 mM) promastigotes. Conclusions: Despite the effectiveness of exogenous PpIX on promastigotes and the production of PpIX by human infected cells, treatment with ALA or MAL before irradiation was unable to completely destroy L. (L.) infantum or L. (V.) panamensis intracellular amastigotes.

Introducción. El tratamiento fotodinámico con ácido 5-aminolevulínico como inductor de la protoporfirina IX (ALA-PpIX) constituye una alternativa interesante en el tratamiento de la leishmaniasis cutánea. Objetivo. Evaluar la producción de protoporfirina IX (PpIX) a partir de la administración de ALA o MAL y el efecto de la PDT con ALA a nivel celular en células THP-1 no infectadas e infectadas con Leishmania ( Viannia ) panamensis o Leishmania ( Leishmania ) infantum (syn. Leishmania chagasi ). Materiales y métodos. La producción de protoporfirina IX y su ‘colocalización´ mitocondrial se evaluaron mediante microscopía ‘confocal´. Se evaluó la toxicidad celular después del tratamiento con los compuestos y la aplicación de irradiación de luz (597-752 nm) en una fluencia de 2,5 J/cm 2 mediante el empleo de la prueba colorimétrica con metil-tiazol-tetrazolio (MTT) en las células, y de métodos microscópicos estándar en los parásitos. Los resultados se expresaron como la concentración del compuesto activo en el 50 % de las células o parásitos (CC 50 o CI 50 ). Resultados. El ácido aminolevulínico o el metil-5-aminolevulinato indujeron la protoporfirina IX endógena en células humanas, y se observó fluorescencia de color rojo en las mitocondrias. La actividad del ácido aminolevulínico y del metil-5-aminolevulinato utilizados con terapia fotodinámica fue similar en las células THP-1 (CC 50 0,16±0,01 mM y 0,33±0,019 mM, respectivamente) y, aparentemente, no inhibió los parásitos en las células infectadas, en comparación con los controles. El tratamiento exógeno con protoporfirina IX y terapia fotodinámica fue tóxico para las células THP-1 (CC 50 0,00032 ±0,00002 mM) y para los promastigotes de L. (L .) infantum (IC 50 0,003±0,0001 mM) y L. ( V .) panamensis (CI 50 0,024±0,0001 mM). Conclusiones. A pesar de la ‘fotoactividad´ del tratamiento con protoporfirina IX en promastigotes y de su producción después del tratamiento con ácido aminolevulínico y metil-5-aminolevulinato en las células infectadas con Leishmania , no se observó daño en los amastigotes presentes en las células de L. ( L .) infantum o L . ( V .) panamensis .

Manual and Rotary Instrumentation Ability to Reduce Enterococcus faecalis Associated with Photodynamic Therapy in Deciduous Molars

This aim of this study was to assess the ability of manual or rotary instrumentation associated with photodynamic therapy (PDT) to reduce Enterococcus faecalis using three combinations of light/photosensitizers: toluidine blue O/laser, fuchsin/halogen light and fuchsin/LED. Twenty deciduous molars were selected and contaminated with Enterococcus faecalis (McFarland 0.5 scale). Working length determination was performed by visual method. The teeth were randomly divided into two groups: G1 (n=10): manual instrumentation (Kerr-type files) and G2 (n=10): rotary instrumentation (ProTaper system). The bacteria were collected three times using sterile paper cones compatible with the anatomic diameter of the root canal for 30 s before and after instrumentation and after PDT. The samples were diluted in peptone water, seeded on blood agar plates and incubated in an oven at 37 °C for colony-forming units counting. The decrease of E. faecalis counts after instrumentation and after PDT was compared using the Wilcoxon test, t-test and Kruskal Wallis test. A significant reduction of E. faecalis occurred after manual and rotary instrumentation and after PDT using the three combinations of light/photosensitizer (p<0.05). It may be concluded that both rotary and manual instrumentation reduced E. faecalis. Fuchsin with halogen light or LED irradiation and toluidine blue O with laser irradiation can be used to reduce E. faecalis in root canals of primary molars. PDT can be used as an adjuvant to conventional endodontic treatment.

O objetivo do presente estudo foi avaliar a redução de Enterococcus faecalis após instrumentação manual ou rotatória associada à terapia fotodinâmica (PDT) utilizando 3 combinações luz/fotossensibilizante: azul de toluidina O/laser, fucsina/luz halógena e fucsina/LED. Foram selecionados 20 molares decíduos que foram contaminados com Enterococcus faecalis (escala 0,5 de McFarland). A odontometria foi feita através do método visual. Os dentes foram divididos aleatoriamente em dois grupos: G1 (n=10): instrumentação manual (limas tipo Kerr) e G2 (n=10): instrumentação rotatória (sistema ProTaper). Foram realizadas coletas com cone de papel estéril compatível com o diâmetro anatômico do canal durante 30 s antes e após a instrumentação e a PDT. As amostras foram diluídas em água peptonada, semeadas em placas de agar-sangue e incubadas em estufa a 37 °C para contagem das unidades formadoras de colônias. As comparações antes da redução de E. faecalis após a instrumentação e após a realização da PDT foram realizadas pelo teste de Wilcoxon, teste t e Kruskal Wallis. Houve redução significante de E. faecalis após a instrumentação manual ou rotatória e após realização da PDT com as três combinações de luz/fotossensibilizante (p<0,05). Pode-se concluir que a instrumentação rotatória e manual acarretou a redução de E. faecalis. A fucsina irradiada com luz halógena ou led e o azul de toluidina irradiado com laser podem ser utilizados para redução de E. faecalis do sistema de canais radiculares de molares decíduos. A terapia fotodinâmica pode ser utilizada como coadjuvante ao tratamento endodôntico convencional.

Changes in physiological and behavioral parameters of preterm infants undergoing body hygiene: a systematic review / Las variaciones de los parámetros fisiológicos y de comportamiento de los recién nacidos pretérminos sometidos a baño de inmersión: una revisión sistemática / Variações nos parâmetros fisiológicos e comportamentais de recém-nascidos pré-termo submetidos à higienização corporal: revisão sistemática

Objective To verify the effect of bathing on the body temperature of preterm infants (PTI). Method Systematic review conducted in the following bibliographic electronic sources: Biblioteca Virtual em Saúde/Lilacs (BVS), Cumulated Index of Nursing and Allied Health Literature (CINAHL), Cochrane Library, Google Scholar, PubMed, SCOPUS and Web of Science, using a combination of search terms, keywords and free terms. The review question was adjusted to the PICO acronym (Patient/population, Intervention, Control/comparative intervention, Outcome). The selected publications were evaluated according to levels of evidence and grades of recommendation for efficacy/effectiveness studies, as established by the Joanna Briggs Institute. Results Eight hundred and twenty four (824) publications were identified and four studies met the inclusion criteria, of which three analyzed the effect of sponge baths and the effect of immersion baths. Conclusion Sponge baths showed a statistically significant drop in body temperature, while in immersion baths the body temperature remained stable, although they studied late preterm infants. .

Objetivo Determinar el efecto del baño en la temperatura corporal del recién nacido prematuro. Método Revisión sistemática realizada en las fuentes bibliográficas electrónicas BVS, CINAHL, Cochrane Library, Google Scholar, PubMed, Scopus y Web of Science. Las búsquedas fueron realizadas mediante combinación de descriptores, palabras clave y términos libres y se ajustó la cuestión de la revisión a la estrategia PICO. Las publicaciones seleccionadas se evaluaron de acuerdo con los niveles de evidencia y grados de recomendación para los estudios de eficacia/efetividad establecidos por el Instituto Joanna Briggs. Resultados Se identificaron 824 publicaciones y cuatro atendieron a los criterios de inclusión, de los cuales, tres analizaron el efecto del baño de esponja y uno el efecto del baño de inmersión. Conclusión El baño de esponja mostró una disminución estadísticamente significativa en la temperatura corporal, en cuanto que el baño de inmersión, la temperatura corporal se mantuvo estable, aunque el estudio haya sido realizado con recién nacidos prematuros tardíos.

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Objetivo Verificar o efeito do banho na temperatura corporal de recém-nascidos pré-termo (RNPT). Método Revisão sistemática realizada nas fontes eletrônicas bibliográficas BVS/Lilacs, Cumulative Index of Nursing and Allied Health (CINAHL), Cochrane Library, Google Scholar, PubMed, SCOPUS e Web of Science, utilizando a combinação de descritores, palavras-chave e termos livres. A pergunta da revisão foi ajustada ao acrônimo PICO (Paciente/população, Intervenção, Intervenção controle/comparativa, Desfecho analisado). As publicações selecionadas foram avaliadas de acordo com os níveis de evidência e graus de recomendação para estudos de eficácia/efetividade estabelecidos pelo Instituto Joanna Briggs. Resultados Foram identificadas 824 publicações e quatro estudos atenderam aos critérios de inclusão, dos quais três analisaram o efeito do banho de esponja e um o efeito do banho de imersão. Conclusão O banho de esponja mostrou queda da temperatura corporal estatisticamente significante, enquanto no banho de imersão a temperatura corporal permaneceu estável, embora tenham sido estudados RNPT tardios. .

Robertsonian chromosomes and the nuclear architecture of mouse meiotic prophase spermatocytes

BACKGROUND: The nuclear architecture of meiotic prophase spermatocytes is based on higher-order patterns of spatial associations among chromosomal domains from different bivalents. The meiotic nuclear architecture depends on the chromosome characteristics and consequently is prone to modification by chromosomal rearrangements. In this work, we consider Mus domesticus spermatocytes with diploid chromosome number 2n = 40, all telocentric, and investigate a possible modification of the ancestral nuclear architecture due to the emergence of derived Rb chromosomes, which may be present in the homozygous or heterozygous condition. RESULTS: In the 2n = 40 spermatocyte nuclei random associations mediated by pericentromeric heterochromatin among the 19 telocentric bivalents ocurr at the nuclear periphery. The observed frequency of associations among them, made distinguishable by specific probes and FISH, seems to be the same for pairs that may or may not form Rb chromosomes. In the homozygote Rb 2n = 24 spermatocytes, associations also mediated by pericentromeric heterochromatin occur mainly between the three telocentric or the eight metacentric bivalents themselves. In heterozygote Rb 2n = 32 spermatocytes all heterochromatin is localized at the nuclear periphery, yet associations are mainly observed among the three telocentric bivalents and between the asynaptic axes of the trivalents. CONCLUSIONS: The Rb chromosomes pose sharp restrictions for interactions in the 2n = 24 and 2n = 32 spermatocytes, as compared to the ample possibilities for interactions between bivalents in the 2n = 40 spermatocytes. Undoubtedly the emergence of Rb chromosomes changes the ancestral nuclear architecture of 2n = 40 spermatocytes since they establish new types of interactions among chromosomal domains, particularly through centromeric and heterochromatic regions at the nuclear periphery among telocentric and at the nuclear center among Rb metacentric ones.

Apoptosis as pathogenic mechanism of infection with vesicular stomatitis virus: evidence in primary bovine fibroblast cultures

To determine whether fibroblasts from Blanco Orejinegro cattle, exhibit any level of resistance to infection against vesicular stomatitis virus (VSV) serotypes Indiana (VSV-I) or New Jersey (VSV-NJ), 30 fibroblast cultures were phenotyped to evaluate their resistance/susceptibility. Thirty three % of Blanco Orejinegro fibroblast cultures were classified as very resistant, 50% as resistant, and 17% as susceptible to VSV-I infection, whereas 20% were classified as very resistant, 50% as resistant and 30% as susceptible to VSV-NJ infection. Therefore, there appears to be a large variation in phenotypic polymorphism among the fibroblasts to infection by VSV. To elucidate the mechanisms responsible for this diversity, we searched for a possible relationship between resistance/ susceptibility and production of factors wi th antiviral activity; however fibroblasts did not secrete factors with antiviral activity. We examined also whether apoptosis where induced by infection and its correlation with the polymorphism of resistance/susceptibility to VSV. Using morphological analyses, hypoploidy measurements, and level of phosphatidyl serine expression, high levels of apoptosis were measured in VSV infected fibroblasts. However, no correlation exists between apoptosis and the category of resistance/susceptibility to infection, indicating that apoptosis is a pathogenic mechanism of VSV.

Vacinação com frações subcelulares de Leishmania (Leishmania) amazonensis sob modulação de Mycobacterium bovis BCG e ciclofosfamida / Vaccination with subcellular fractions of Leishmania (Leishmania) amazonensis under modulation of Mycobacterium bovis BCG and ciclofosfamida

Frações subcelulares obtidas de promastigotas de Leishmania (Leishmania) amazonensis foram utilizadas em associação com imunomoduladores para vacinar camundongos contra uma infecção pelo parasita. Um protocolo de fracionamento permitiu a obtenção de três frações subcelulares, denominadas fração flagelar (FF), fração de membrana (FM) e fração microssomal (FMic) que, caracterizadas por microscopia eletrônica de transmissão e gel de SDS-PAGE, mostraram alto grau de purificação. Todas as frações foram capazes de induzir e revelar uma reação de hipersensibilidade retardada em camundongos previamente imunomodulados pelo Bacilo Calmette-Guérin (BCG), mostrando-se assim imunogênicas. O BCG é um potente estimulador da resposta celular Th1, ativando macrófagos e aumentando sua atividade microbicida. Os macrófagos estão envolvidos na infecção tanto como alvo do parasita quanto no seu combate, que é dependente de uma resposta fundamentalmente celular. A resistência à infecção por Leishmania tem sido associada a indução de uma resposta Th1. Esta resposta levaria à cura, enquanto a progressão da doença estaria associada à resposta Th2. Admite-se que indivíduos clinicamente curados desenvolvam resistência, tornando-se imunes a novas lesões. Baseado nisto, a busca por uma vacina contra esta doença parece uma alternativa viável. O presente trabalho utilizou um protocolo experimental de vacinação em que foram empregadas frações subcelulares de promastigotas em associação com BCG e ciclofosfamida (CY). A CY é uma droga imunossupressora, mas após o fim de seu efeito citotóxico provoca uma explosão de monócitos e neutrófilos na medula óssea, aumentando o número destas células na circulação. Quando camundongos foram vacinados com FM em associação com ambos os imunomoduladores e posteriormente desafiados com promastigotas de L. (L.) amazonensis, obteve-se proteção parcial, conforme observado pela cinética da lesão, histopatologia e quantificação de parasitos. Quando o desafio foi...

Cyclic 3'-5' guanosine monophosphate-dependent activity in Leishmania amazonensis

Although there are some data concerning the nitric oxide and the cyclic 3'-5'guanosine monophosphate (cGMP) signaling pathway in trypanosomatids, there is no report about the cGMP-dependent enzymatic activity identification. In this sense, a cGMP dependent activity was detected on soluble fraction from Leishmania amazonensis promastigotes with a high metacyclic level. This information is valuable in order to explore the metabolic pathway of G kinase protein in this parasite

Odontologic use of copper/aluminum alloys: mitochondrial respiration as sensitive parameter of biocompatibility

Copper/aluminum alloys are largely utilized in odontological restorations because they are less expensive than gold or platinum. However, tarnishing and important corrosion in intrabuccal prostheses made with copper/aluminum alloys after 28 days of use have been reported. Several kinds of food and beverage may attack and corrode these alloys. Copper is an essential component of several important enzymes directly involved in mitochondrial respiratory metabolism. Aluminum, in contrast, is very toxic and, when absorbed, plasma values as small as 1.65 to 21.55 µg/dl can cause severe lesions to the nervous system, kidneys, and bone marrow. Because mitochondria are extremely sensitive to minimal variation of cellular physiology, the direct relationship between the mitocondrial respiratory chain and cell lesions has been used as a sensitive parameter to evaluate cellular aggression by external agents. This work consisted in the polarographic study of mitochondrial respiratory metabolism of livers and kidneys of rabbits with femoral implants of titanium or copper/aluminum alloy screws. The experimental results obtained did not show physiological modifications of hepatic or renal mitochondria isolated from animals of the three experimental groups, which indicate good biocompatibility of copper/aluminum alloys and suggest their odontological use

Subcellular distribution of prostaglandin-E2 and prostaglandin-F2alpha in atrial tissue from patients with mitral valve disease

The distribution of prostaglandin-E2 (PGE2) and prostaglandin-F2alpha (PGF2alpha) was studied in subcellular fractions isolated from homogenates of human atrial fresh tissue by differential centrifugation. Right and left atrial samples were excised from the same heart of six patients with mitral valve disease at the time of open heart surgery. The atrial fractions investigated were mitochondrial (8,500 g pellet), microsomal (100,000 g pellet) and cytosol soluble (100,000 g supernatant) fractions. After extraction of prostaglandins from the three atrial fractions and separation of PGE from PGF series by chromatography on silicic acid column, these prostaglandins were measured by radioimmunoassay. The results, showed that PGE2 and PGF2alpha were located mainly in the soluble cytosolic fraction of right and left atrial tissue (p<0.001). Furthermore, the prostaglandins levels were higher in left than in right atria of these patients (p<0.001). The relation between prostaglandins heart generation in response to elevated work load of mitral valve disease is discussed.

Efeito das vastatinas sobre a hidrólise hepática do colesterol esterificado, em células de hepatoblastoma humano HEP G2 / Effects of vastatins in the hepatic hidrolase of esterified cholesterol in human HEP G2 hepatoblastoma cells

O presente trabalho se valeu de células de hepatoma humano Hep G2 para estudar se existe algum efeito das vastatinas sobre a atividade das enzimas que governam a hidrólise hepática do coleterol: colesterol éster hidrolases lisossomal, citosólica e microssomal. As enzimas foram incubadas com ou sem amostras de vastatina, dissovidas em dimetilsulfóxido. A adiçao das vastatinas ofereceu distintos resultados, conforme a maneira que se apresentou o substrato às enzimas. No caso da colesterol éster hidrolase lisossomal, obteve-se inibiçao em substrato Hajjar, com sais biliares, e estimulaçao em substrato Brecher, desprovido de sais biliares. A hidrolase citosólica teve sua atividade inibida em substrato Hajjar e constante em substrato Brecher.

Isolation and biochemical characterization of the plasma membrane of Tritrichomonas foetus

A fraction containing plasma membrane-enriched vesicles has been prepared from Tritrichomonas foetus. Cells were ruptured using a Potter type homogenizer, under well controlled conditions, and membranes were isolated by differential centrifugation and in discontinuous sucrose gradient. This fraction was enriched 8 and 10-fold in the plasma membrane marker enzymes 5'-nucleotidase and (Na+ + K+)-dependent, ouabain-sensitive ATPase, respectively. Determination of Glucose-6-phosphatase and NADPH cytochrome c reductase activities in this fraction, indicates a minimal contamination with endoplasmic reticulum membranes. Analysis by Sodium Dodecyl Sulfate-Polyacrylamide (SDS-PAGE) gradient gel showed that the plasma membrane fraction contains several proteins with major bands corresponding to apparent molecular weights of 48, 45, 39, 37, 32, 30, 27, 23, 20, 19, 17, and 15 kDa.

A brain soluble fraction inhibits synaptosomal membrane but not astrocyte ATPase activity

Since a brain soluble fraction (peak II) is known to be able to inhibit synaptosomal membrane Na+, K+-ATPase activity, here we attempted to compare its effect on cellular and subcellular brain components such as synaptosomal and astrocytic membranes, as well as mitochondrial preparations. Peak II highly inhibited total ATPase in synaptosomal membranes but failed to modify enzyme activity in astrocytic and mitochondrial preparations. Findings suggest cellular and subcellular specificity of peak II on brain ATPase activity.

Subcellular distribution and pharmacological characterization of muscarinic receptors in tracheal smooth muscle

: Subcellular fractions isolated from tracheal smooth muscle have been identified using biochemical markers and measuring the [3H]QNB muscarinic receptor binding activity in these fractions. This muscarinic receptor (mAchR) activity was slightly enriched 1.6 times in the crude mitochondrial fraction (M), 2.6 times in the crude microsomal fraction (P), and greatly enriched in the highly purified plasma membranes fractions, being 5.3 times in a heavy plasma membrane fraction designed as P2 and 9.1 times in a light plasma membrane fraction named P1 fraction. The muscarinic receptor subtypes present in the subcellular fractions were identified using competition experiments. The binding of five selective antagonists, pirenzepine, AF-DX 116, hexahydrodifenidol, methoctramine and 4-DAMP were examined. In this sense, the M1 antagonist pirenzepine showed pKi's values between 6.44-7.45 and the M2 antagonist AF-DX 116 showed pKi's values ranging from 6.75 to 7.45 being the lowest pKi's values here described. The antagonist hexahydrodifenidol showed higher affinities than pirenzepine-derivated compounds with pKi's values from 7.25 to 7.65. The antagonist 4-DAMP exhibited pKi's values from 8.18-8.41. Finally, methoctramine showed similar affinities as 4-DAMP, with pKi's ranging from 8.09 to 8.22 suggesting the existence of M2 receptors in these fractions. These data suggest that M2 mAchR are present in all articulate fractions here studied. It is important to emphasize that the M2 muscarinic receptor presents in the light plasma membrane fraction (P1) shows poor selectivity towards the muscarinic antagonists being different from the M2 mAchRs associated with other subcellular fractions isolated from bovine tracheal smooth muscle

Aggregatory behaviour of platelets incubated with subcellular fractions of normal and chagasic human syncytiotrophoblast

The surface of human syncytiotrophoblast does not induce maternal blood platelet aggregation even though it is not an endothelium. It can be surmised that as occurs in endothelial injury the subcellular components of the syncytiotrophoblast may have pro- or antiaggregatory activity. During congenital Chagas' disease which is associated to trophoblast lesions, platelets may play a role in the development of T. cruzi-induced placentitis. In the present work the aggregatory behaviour of normal human blood platelets was recorded after their challenging with subcellular fractions of syncytiotrophoblast isolated from normal and chagasic women. Nuclear, Mitochondrial, Microsomal and Supernatant fractions isolated from normal and chagasic syncytiotrophoblast failed to induce per se any aggregatory reaction on platelets. When samples of platelet-rich plasma (PRP) were preincubated with normal and chagasic nuclear fractions and then stimulated with collagen at threshold level (CT-PRP) an inhibition of the aggregatory response was observed. Treatment of CT-PRP with normal and chagasic mitochondrial fractions induced inhibition of platelet aggregation whereas only chagasic fraction reduced latency time. Microsomal fraction from normal placentas showed no significant effects on platelet aggregation. It is concluded that subcellular fractions of normal human syncytiotrophoblast do not exhibit any effect on platelet aggregation, whereas those subcellular fractions enriched in intracellular membrane components isolated from chagasic placentas inhibit platelet aggregation.

Intercambio de proteinas entre homogeneizados de plaquetas humanas y liposomas de lecitina / Exchange of proteins between human homogenized platelets and lecithin liposomes

Liposomas de lecitina de yema de huevo obtenidos por sonicación fueron incubados durante 30 min en medio salino con homogeneizados de plaquetas humanas con tratamiento y sin tratamiento previo con ácido dicarboxílico-bisdimetilamida (DIAMID). La mezcla fue separada por ultracentrifugación en gradiente de densidad y la caracterización de las proteínas absorbidas a la membrana liposomal se realizó mediante electroforesis en gel de poliacrilamida (PAGE). Se encontró que proteínas provenientes tanto del citoesqueleto plaquetario como de otras partes eran incorporadas a la membrana liposomal

In vitro uptake of 18-hydroxycorticosterone by regions of the central nervous system

Estudiamos la unión específica de la 18-hidroxicorticosterona (18-OH-B) a fracciones nucleares y citoplasmáticas de células provenientes de bulbo, protuberancia, amígdala, pituitaria anterior, hipotálamo, hipocampo, área preóptica y pulmón de animales adrenalectomizados, después de incubar los tejidos con el ligando radiactivo. Encontramos que 18-OH-B tiene una mayor unión específica a núcleos obtenidos de bulbo y protuberancia; este perfil difiere de observaciones previas en las que otros corticosteroide íntimamente relacionados, como la corticosterona y la aldosterona, se encuentran principalmente concentrados en el sistema límbico