Danos ao DNA promovidos por ácido 5-aminolevulínico: possível associação com o desenvolvimento de carcinoma hepatocelular em portadores de porfiria aguda intermitente

5-Aminolevulinic acid (ALA) is a heme precursor accumulated in acute intermittent porphyria (AIP), which might be associated with hepatocellular carcinoma (HCC) in symptomatic patients. Under metal catalyzed oxidation, ALA and its cyclic dimerization product, 3,6-dihydropyrazine-2,5-dipropanoic acid, produce reactive oxygen species that damage plasmid and calf thymus DNA bases, increase the steady state level of 8-oxo-7,8-dihydro-2´-deoxyguanosine in liver DNA and promote mitochondrial DNA damage. The final product of ALA, 4,5-dioxovaleric acid (DOVA), is able to alkylate guanine moieties, producing adducts. ALA and DOVA are mutagenic in bacteria. This review shows an up-to-date literature data that reinforce the hypothesis that the DNA damage induced by ALA may be associated with the development of HCC in AIP patients.

Formação de adutos exocíclicos com bases de DNA: implicações em mutagênese e carcinogênese

A number of ring-extended DNA adducts resulting from reaction of alpha,beta-unsaturated aldehydes, or their epoxides, with DNA bases have been characterized in recent years. These adducts can lead to miscoding during DNA replication which, if not repaired, result in mutations that can contribute to cancer development. Recently, the use of ultrasensitive methods allowed the detection of background levels of etheno DNA adducts in tissues of untreated animals and humans suggesting the existence of endogenous sources of reactive intermediates. In this review, we briefly summarize the recent advances in the chemistry of these DNA lesions.

Oxidação de proteínas por oxigênio singlete: mecanismos de dano, estratégias para detecção e implicações biológicas

Proteins are potential targets for singlet molecular oxygen (¹O2) oxidation. Damages occur only at tryptophan, tyrosine, histidine, methionine, and cysteine residues at physiological pH, generating oxidized compounds such as hydroperoxides. Therefore, it is important to understand the mechanisms by which ¹O2, hydroperoxides and other oxidized products can trigger further damage. The improvement and development of new tools, such as clean sources of ¹O2 and isotopic labeling approaches in association with HPLC/mass spectrometry detection will allow one to elucidate mechanistic features involving ¹O2-mediated protein oxidation.

Aplicações de nanoeletrodos como sensores na Química Analítica

Nanomaterials make up an emerging area in Chemistry and in the science of materials. This area constitutes the development of methods for synthesizing nanoscopic particles of a given material used for scientific investigation. Nanomaterials have a wide range of commercial possibilities and technological applications, including their use in analytical chemistry, as well as in electronics, optics, engineering, medicine, devices for liberation of drugs, bioencapsulation, among others. This paper presents a summary about nanoelectrodes, devices built from nanoparticles, which show great potential as electrochemical tools in many different types of analysis. The purpose of this paper is to review the construction methodologies of nanoelectrodes, and to point out their successful applicability in the various fields of immune assays and other analytical procedures with quantitative purposes.

Estresse oxidativo, lesões no genoma e processos de sinalização no controle do ciclo celular

The generation of reactive oxygen species (ROS) may be both beneficial to cells, performing functions in intracellular signaling and detrimental, modifying cellular biomolecules. ROS can cause DNA damage, such as base damage and strand breaks. Organisms respond to chromosome insults by activation of a complex and hierarchical DNA-damage response pathway. The extent of DNA damages determines cell fate: cell cycle arrest and DNA repair or cell death. The ATM is a central protein in the response to DNA double-strand breaks by acting as a transducer protein. Collected evidences suggest that ATM is also involved in the response to oxidative DNA damage.

Características ópticas e morfológicas de nanoestruturas de ouro

The present study describes a new procedure to obtain gold nanoparticles, directly in the pores of polycarbonate membranes commonly used in ultrafiltration. The dimensions of the particles may be controlled through the reduction time of the ions in the channels of the harbor matrix. The dissolution of the metallized polymer enables an investigation of the optical and morphologic properties of these elements.

Avaliação sensorial de cachaça

The hedonic level of commercial cachaças, was evaluated by consumers and by a tasters. The results of sensorial methods analyzed trough Principal Components Analysis, Hierarchical Cluster Analysis and the Pearson linear correlation indicated that the best classified cachaças were produced in copper stills and aged in oak casks. By contrast the worst classified exhibited as the main features be not aged and high alcohol percentage. The index of preference is positively correlated with the intensity of yellow color, wood flavor, sweetness and fruit aroma. There is a negative preference correlation with the acidity, the taste of alcohol and bitterness.

Plasmid DNA damage induced by singlet molecular oxygen released from the naphthalene endoperoxide DHPNO2 and photoactivated methylene blue

To investigate oxidative lesions and strand breaks induction by singlet molecular oxygen (¹O2), supercoiled-DNA plasmid was treated with thermo-dissociated DHPNO2 and photoactivated-methylene blue. DNA lesions were detected by Fpg that cleaves DNA at certain oxidized bases, and T4-endoV, which cleaves DNA at cyclobutane pyrimidine dimers and apurinic/apyrimidinic (AP) sites. These cleavages form open relaxed-DNA structures, which are discriminated from supercoiled-DNA. DHPNO2 or photoactivated-MB treatments result in similar plasmid damage profile: low number of single-strand breaks or AP-sites and high frequency of Fpg-sensitive sites; confirming that base oxidation is the main product for both reactions and that ¹O2 might be the most likely intermediate that reacts with DNA.

An isolate of Apple stem grooving virus associated with Cleopatra mandarin fruit intumescence

A citrus tatter leaf isolate (CTLV-Cl) of Apple stem grooving virus (ASGV) has been found to be associated with a fruit rind intumescence in Cleopatra mandarin (Citrus reshni) in Limeira (SP). The CTLV-Cl was mechanically transmitted to the main experimental herbaceous hosts of CTLV. Chenopodium quinoa and C. amaranticolor reacted with local lesions and systemic symptoms while other test plants reacted somewhat differently than what is reported for CTLV. A pair of primers designed for specific detection of ASGV and CTLV amplified the expected 801 bp fragment from the CTLV-Cl-infected plants. Typical capillovirus-like particles were observed by the electron microscope in experimentally infected C. quinoa and C. amaranticolor leaves.

Perfuração gástrica secundária a tricobezoar gigante: descrição de caso e revisão da literatura

Gastric bezoars are impactations offoreign material in lhe stomach. When they are caused by hail; they are named tricho- bezoars. The complications oftrichobezoars are very rare. In this papel; we describe a case of a 16-year-old girl that had a previous history oftricophagia, and had an acute abdominal pain with a pneumoperitoneum in the abdomen radiography. An operation was performed and a gastric perforation was founded associated with a giant trichobezoa7: The trichobezoar was removed by traction through a gastrostomy which was performed in order to remove lhe trichobezoa7: Some fragments of the ulcer were obtained to histological study. The gastrostomy was treated by a gastrorraphy confection. In lhe post- operative period a left subfrenic abscess was revealed and has been drained by laparatomy 15 days after the fisrt operation. After the second surgical procedure the patient had a good evolution, and left the hospital in good health conditions.

Linfangioma de cordão espermático

We describe a case of a 22-year-old man that had been submitted to a left herniorraphy 11 years previously to the present admission. He returned to our hospital with another mass in the same side of the groin. At operation, several small cysts linked to the spermatic cord were demonstrated. At this time, an histological exam demonstrated the presence of conective tissue. The final histology report confirmed the diagnosis of lymphangioma of the spermatic cord in the groin region. The patient was discharged from the hospital in a good health, with no complications.

Complicações vasculares pós-transplante hepático

OBJETIVO: O objetivo do estudo é apresentar as complicações vasculares arteriais e venosas observadas em um serviço de transplante hepático universitário brasileiro. MÉTODOS: Os prontuários de todos os pacientes submetidos a transplante hepático no período de setembro de 1991 a janeiro de 2000 foram analisados para determinar as complicações vasculares e correlacioná-las a dados clínicos e do procedimento cirúrgico. RESULTADOS: Foram realizados 169 transplantes, sendo quatro inter vivos e nove retransplantes. Um total de 24 complicações vasculares (14,3%) foi identificado em 22 pacientes (13,0%). A complicação vascular mais comum foi a trombose da artéria hepática (15 casos), seguido da trombose da veia porta (quatro casos). Complicações da veia cava inferior infra ou supra-hepática foram incomuns, ocorrendo em um total de três casos (1,8%). As complicações vasculares foram mais freqüentes nas crianças (26,06%) do que em adultos (13,14%) (p<0,05). Dos pacientes com trombose da artéria hepática, um foi submetido à angioplastia, um a trombectomia, oito a retransplante e cinco evoluíram para o óbito enquanto aguardavam retransplante. Dos quatro casos de trombose da veia porta, dois foram a óbito, um foi submetido à colocação percutânea de prótese e um a tratamento conservador. Os pacientes com estenose da veia porta e da veia cava inferior infra e supra-hepática foram submetidos a tratamento conservador, com boa evolução clínica. CONCLUSÕES: que as complicações vasculares são freqüentes após o transplante hepático, principalmente em crianças, e são associadas à elevada morbidade, mortalidade e retransplante.

Accuracy of modelling and identification of malfunctions in rotor systems: experimental results

The accuracy of modelling of rotor systems composed of rotors, oil film bearings and a flexible foundation, is evaluated and discussed in this paper. The model validation of different models has been done by comparing experimental results with numerical results by means. The experimental data have been obtained with a fully instrumented four oil film bearing, two shafts test rig. The fault models are then used in the frame of a model based malfunction identification procedure, based on a least square fitting approach applied in the frequency domain. The capability of distinguishing different malfunctions has been investigated, even if they can create similar effects (such as unbalance, rotor bow, coupling misalignment and others) from shaft vibrations measured in correspondence of the bearings.

Misticismo do cálculo e a ascese consumista: razão e fé no "crer sem pertencer" e no neopentecostalismo

A cultura do cálculo engendra duas formas de individualização: 1) o isolamento do indivíduo como "peça" nos processos formalizados (nos repetitivos ciclos do consumo e na lógica organizacional da burocracia), o qual coloca a consciência numa condição de heteronomia; 2) a liberdade do homem decorrente da possibilidade de controlar a natureza física e social, que desenvolve uma condição de autonomia da consciência. Na última vertente, o cálculo acaba por lidar com seus próprios limites e, portanto, está destinado a agir no limiar do misticismo. As duas principais formas de desinstitucionalização religiosa de nossos dias, quais sejam, a representada pelos movimentos neopentecostais (de recorte consumista) e a chamada "secularização encantada" (de recorte místico), remontam àquelas duas forças individualizantes da cultura do cálculo.

beta-caroteno, ácido ascórbico e antocianinas totais em polpa de frutos de aceroleira conservada por congelamento durante 12 meses

Objetivou-se avaliar as alterações de b-caroteno, ácido ascórbico e antocianinas totais na polpa de frutos de clones de aceroleira conservada por congelamento. Os frutos dos clones BRS 152 (Sertaneja) BRS 235 (Apodi), BRS 236 (Cereja), BRS 237 (Roxinha), BRS 238 (Frutacor) e II 47/1 foram colhidos no estádio de maturação comercial (vermelho maduro) em Limoeiro do Norte, Ceará, Brasil, transportados para a Planta Piloto de Processamento de Frutos da Embrapa Agroindústria Tropical, despolpados, acondicionada a polpa em sacos de polietileno (100 g), congelada, mantida em freezer a -20 °C, e avaliada a cada 30 dias durante 12 meses. O experimento foi realizado em delineamento experimental inteiramente casualizado em esquema fatorial 6 x 13 (clones x tempo), com 3 repetições. A concentração de beta-caroteno foi estável no clone Cereja, enquanto, nos demais, houve decréscimo durante todo o período do experimento. Houve pequeno decréscimo no teor de ácido ascórbico em todos os clones estudados durante o armazenamento, provavelmente devido à alta acidez da polpa, que auxilia na manutenção deste nutriente. O teor de antocianinas totais foi estável nos clones Frutacor e Sertaneja, enquanto nos demais houve diminuição. O clone II 47/1 foi dentre os estudados o que apresentou maiores teores de ácido ascórbico e antocianinas totais, mantendo estas características durante todo o armazenamento. De um modo geral, os clones em que se determinou menor teor de beta-caroteno foram observadas as mais elevadas concentrações de antocianinas totais.