Cytotoxicity of Diepoxybutane and Epichlorohydrin in Relation to Stages of the Cell Cycle

Work conducted in the Millard Biochemistry Research Laboratory examines the dual nature of molecules as carcinogens and anti-tumor agents through the molecular mechanisms of duplex DNA damage by bifunctional alkylating agents. Diepoxybutane (DEB) and epichlorohydrin (ECH) are polar molecules that form covalent DNA interstrand lesions by cross-linking the N7 position of deoxyguanosine residues. A recent experiment indicated that ECH preferentially targets nuclear DNA over mitochondrial DNA, whereas DEB shows similar rates of lesion formation for both loci. It was concluded that preferential targeting of nuclear DNA results from relatively poor uptake of ECH across the mitochondrial membrane. The objective of my honors research was to determine if the cytotoxicities of DEB and ECH vary according to the presence of the nuclear envelope in 6C2 chicken erythro-progenitor cells. The cytotoxicity of DEB and ECH was compared between cells randomly distributed throughout the cell cycle (Go/G, and S » G2/M) and cells enriched in G2/M stages. Results indicated that ECH is more cytotoxic than DEB in both unsynchronized control 6C2 cells and synchronized 6C2 cells enriched in G2/M stages of the cell cycle. Treatment with either bifunctional alkylating agent induced greater cytotoxicity in 6C2 cells enriched in G2/M stages than in unsynchronized control 6C2 cells, suggesting that the presence of the nuclear envelope-or any plasma membrane-may inhibit the reactivity of DEB and ECH.

Quantitative Analysis of Diepoxybutane Damage within the Chicken β-globin Domain

In industrial polymer and synthetic rubber production facilities, workers are exposed to 1,3-butadiene. This compound is converted in vivo to 1,2,3,4-diepoxybutane (DEB) and has been linked to increased incidences of cancer in these individuals. Carcinogenesis has been attributed to formation of DEB induced DNA interstrand cross-links. Previous studies have demonstrated that DEB cross-links deoxyguanosine residues within 5'-GNC sequences in synthetic DNA, in restriction fragments, and in defined sequence nucleosomes. The current study utilized the polymerase chain reaction (PCR) to examine DEB damage frequencies within nuclear genes, found within "open" regions of chromatin, as compared to regions of unexpressed sequence that reside in tightly packed, "closed" chromatin, to more closely model DEB reactivity in vivo. These initial studies have been performed in chicken liver homogenates. Preliminarily, we have found a dose-dependent DEB lesion-forming response within "open" chromatin. DEB appears to have little-to-no effect upon regions of "closed" chromatin.

Mapping of Diepoxybutane Damage in the Cytochrome b Domain of Mitochondrial DNA and the β-globin Domain of Nuclear Chicken DNA Using Quantitative PCR

Diepoxybutane (DEB), a known industrial carcinogen, reacts with DNA primarily at the N7 position of deoxyguanosine residues and creates interstrand cross-links at the sequence 5'-GNC. Since N7-N7 cross-links cause DNA to fragment upon heating, quantative polymerase chain reaction (QPCR) is being used in this experiment to measure the amount of DEB damage (lesion frequency) with three different targets-mitochondrial (unpackaged), open chromatin region, and closed chromatin region. Initial measurements of DEB damage within these three targets were not consistent because the template DNA was not the limiting reagent in the PCR. Follow-up PCR trials using a limiting amount of DNA are still in progress although initial experimentation looks promising. Sequencing of these three targets to confirm the primer targets has only been successfully performed for the closed chromatin target and does not match the sequence from NIH used to design that primer pair. Further sequencing trials need to be conducted on all three targets to assure that a mitochondrial, open chromatin, and closed chromatin region are actually being amplified in this experimental series.

Changes in Apoptotic Gene Expression Induced by DNA Cross-Linkers

The Millard Research Laboratory is interested in the cytotoxic mechanisms of the bifunctional alkylators diepoxybutane (DEB), epichlorohydrin (ECH), and (1-chloroethenyl) oxirane (COX). Studies performed in the laboratory examine the dual nature of these DNA cross-linking compounds that can act as carcinogens or anti-cancer agents. The mechanisms through which these compounds induce cell death are explored in this study. Cells either undergo cell death due to necrosis or apoptosis. HL-60 cells were treated with varying concentrations of DEB, ECH, or COX. A caspase 3/7 assay was used to test for induction of apoptosis in the treated cells at varying incubation times. It was concluded that DEB induces apoptosis in HL-60 cells treated with 100 μM for 24 hours. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was then used to explore the changes in gene expression of various genes involved in apoptosis signaling. The results were inconclusive as to specific genes involved in DEB induced apoptosis, but the data does suggest that apoptosis is induced by a mitochondrial-mediated apoptosis signaling pathway.

Apreçamento de opções de recompra embutidas: uma aplicação ao mercado de debêntures brasileiro

Nesse trabalho desenvolvemos uma estratégia para o apreçamento de opções de recompra Embutidas . Esse tipo específico de opção está presente em um grande número de debêntures no mercado brasileiro. Em função deste mercado apresentar um número reduzido de ativos, o apreçamento destas opções se faz necessário para que tenhamos condições de ampliar a massa de ativos disponíveis para a análise. Como passo intermediário, é preciso determinar quando é interessante para o emissor efetuar o resgate antecipado da debênture. Para este m, propomos uma metodologia para a estimação da estrutura a termo da taxa de juros do mercado de debêntures com base no modelo de Nelson-Siegel.

Modified value stream mapping of airport check-in procedures

In June 2014 Brazil hosted the FIFA World Cup and in August 2016 Rio de Janeiro hosts the Summer Olympics. These two seminal sporting events will draw tens of thousands of air travelers through Brazil’s airports, airports that are currently in the midst of a national modernization program to address years of infrastructure neglect and insufficient capacity. Raising Brazil’s major airports up to the standards air travelers experience at major airports elsewhere in the world is more than just a case of building or remodeling facilities, processes must also be examined and reworked to enhance traveler experience and satisfaction. This research paper examines the key interface between airports and airline passengers—airport check-in procedures—according to how much value and waste there is associated with them. In particular, the paper makes use of a value stream mapping construct for services proposed by Martins, Cantanhede, and Jardim (2010). The uniqueness of this construct is that it attributes each activity with a certain percentage and magnitude of value or waste which can then be ordered and prioritized for improvement. Working against a fairly commonly expressed notion in Brazil that Brazil’s airports are inferior to the airports of economically advanced countries, the paper examines Rio’s two major airports, Galeão International and Santos Dumont in comparison to Washington D.C.’s Washington National and Dulles International airports. The paper seeks to accomplish three goals: - Determine whether there are differences in airport passenger check-in procedures between U.S. and Brazilian airports in terms of passenger value - Present options for Brazilian government or private sector authorities to consider adopting or implementing at Brazilian airports to maximize passenger value - Validate the Martins et al. construct for use in evaluating the airport check-in procedures Observations and analysis proved surprising in that all airports and service providers follow essentially the same check-in processes but execute them differently yet still result in similar overall performance in terms of value and waste. Although only a few activities are categorized as completely wasteful (and therefore removed in the revised value stream map of check-in activities), the weighting and categorization of individual activities according to their value (or waste) presents decision-makers a means to prioritize possible corrective actions. Various overall recommendations are presented based on this analysis. Most importantly, this paper demonstrates the viability of using the construct developed by Martins et al to examine airport operations, as well as its applicability to the study of other service industry processes.

Neuronal Assembly Detection and Cell Membership Specification by Principal Component Analysis

LOPES-DOS-SANTOS, V. , CONDE-OCAZIONEZ, S. ; NICOLELIS, M. A. L. , RIBEIRO, S. T. , TORT, A. B. L. . Neuronal assembly detection and cell membership specification by principal component analysis. Plos One, v. 6, p. e20996, 2011.

Digestibilidade aparente da matéria seca, matéria orgânica e energia bruta e nutrientes digestíveis totais de uma ração completa para bovinos de diferentes grupos genéticos

Avaliou-se a digestibilidade da matéria seca (DMS), matéria orgânica (DMO) e energia bruta (DEB) e os nutrientes digestíveis totais (NDT) de uma ração completa, composta por 44,3% de feno de capim-braquiaria, 55% de concentrado e 0,7% de mistura mineral, fornecida a bovinos de diferentes grupos genéticos (Gir, Nelore, Guzerá, Santa Gertrudis e Caracu), pelas metodologias de coleta total de fezes e com indicador interno (lignina em detergente ácido -- LDA), em delineamento inteiramente casualizado, com três repetições por grupo genético, com análise de variância individual dentro de cada metodologia e uma análise de correlação entre as metodologias. As correlações foram médias ( 0,47 a 0,51) e significativas (P<0,0602; P<0,0697; P<0,0747; P<0,0522), respectivamente, para DMS, DMO, DEB e para NDT. A recuperação do indicador (95,06%) foi semelhante entre os grupos genéticos. Não houve diferença entre grupos genéticos para DMS, DMO, DEB e nos valores de NDT pelas metodologias de coleita total de fezes e com LDA, com médias de 53,31 e 50,33; 55,16 e 52,25; 52,22 e 49,20; e 53,39 e 50,61%, respectivamente. Assim, a LDA foi eficiente na estimativa da digestibilidade, em função de sua adequada recuperação. Os nutrientes foram utilizados de forma semelhante pelos grupos genéticos.

Hypercapnic ventilatory response of anesthetized female rats subjected to neonatal maternal separation: Insight into the origins of panic attacks?

Neonatal maternal separation (NMS) is a form of stress that interferes with the regulation of the stress response, an effect that predisposes to the emergence of panic and anxiety related disorders. We previously showed that at adulthood, awake female (but not male) rats subjected to NMS show a hypercapnic ventilatory response (HCVR; 5% CO(2)) that is 63% greater than controls (Genest et al., 2007). To understand the mechanisms underlying the sex-specific effects of NMS on the ventilatory response to CO(2), we used two different anesthetized female rat preparations to assess central CO(2) chemosensitivity and contribution of sensory afferents (stretch receptors and peripheral chemoreceptors) that influence the HCVR. Data show that anesthesia eliminated the respiratory phenotype observed previously in awake females and CO(2) chemosensitivity did not differ between groups. Finally, the assessment of the ovarian hormone levels across the oestrus cycle failed to reveal significant differences between groups. Since anesthesia did not affect the manifestation of NMS-related respiratory dysfunction in males (including the hypercapnic ventilatory response) (Kinkead et al., 2005; Dumont and Kinkead, 2010), we propose that the panic or anxiety induced by CO(2) during wakefulness is responsible for enhancement of the HCVR in NMS females. (C) 2011 Elsevier B.V. All rights reserved.

A formação pós-graduada em ensino de ciências naturais e matemática de docentes do IFRN: implicações na atuação docente

This research part of the educational context of the Federal Rio Grande do Norte, through the resumption of legal frameworks that characterize it as an institution belonging to the Federal Network of Professional Education and Technology Brazilian, with a focus on continued education policies for the servers who work there specifically teachers, especially those who have their work in the Teaching of Natural Science and Mathematics. To do this the cut in an agreement between the IFRN and UFRN PPGECNM through the professional master's degree Teaching of Natural Sciences and Mathematics. This agreement as we have research collaborators 08 master teachers who graduated in the period 2004 to 2010, so we undertook a qualitative and quantitative research aimed to conduct the study in general terms of description and analysis of the impacts caused by the formation of masters IFRN in PPGECNM UFRN, taking into account the production of the same academic (dissertation), his performance in the context of the institution and the historical, social, economic and political aspects involved, and also meet the guidelines of the project at the Observatory in 2008 - MEC / CAPES / BSD-P. We used the theoretical options methodological elements of Comprehensive Interview and multireferentiality, our data collection instrument was the main interview, we also performed the analysis of dissertations by lecturers and teachers featured, from the specific descriptors used in catalogs USP / IFUSP (1992, 1996) and UNICAMP / FE / CEDOC (1998) and by other researchers. In analyzing and understanding the speech of the interviewees were able to identify the implications of teacher education in the school context, the motivation to seek the Master; how was the construction of the object of study of the educational product and its use in teaching practice and intervention, the question of the role of master teachers in the school environment to the post master taking into account changes in professional performance and influence in the working groups, how does the use of research and investigation in the classroom after training and between training and educational quality in the context of IFRN. In reading and analysis of the dissertations were able to identify the main focus and under-explored thematic focus as well as the theoretical methodological references. At the end of the research developed a product that could be used for technical analysis studies and assessment in quantitative terms the results achieved by the master teachers IFRN through his training in PPGECNM UFRN

Experience-dependent upregulation of multiple plasticity factors in the hippocampus during early REM sleep

Sleep is beneficial to learning, but the underlying mechanisms remain controversial. The synaptic homeostasis hypothesis (SHY) proposes that the cognitive function of sleep is related to a generalized rescaling of synaptic weights to intermediate levels, due to a passive downregulation of plasticity mechanisms. A competing hypothesis proposes that the active upscaling and downscaling of synaptic weights during sleep embosses memories in circuits respectively activated or deactivated during prior waking experience, leading to memory changes beyond rescaling. Both theories have empirical support but the experimental designs underlying the conflicting studies are not congruent, therefore a consensus is yet to be reached. To advance this issue, we used real-time PCR and electrophysiological recordings to assess gene expression related to synaptic plasticity in the hippocampus and primary somatosensory cortex of rats exposed to novel objects, then kept awake (WK) for 60 min and finally killed after a 30 min period rich in WK, slow-wave sleep (SWS) or rapid-eye-movement sleep (REM). Animals similarly treated but not exposed to novel objects were used as controls. We found that the mRNA levels of Arc, Egr1, Fos, Ppp2ca and Ppp2r2d were significantly increased in the hippocampus of exposed animals allowed to enter REM, in comparison with control animals. Experience-dependent changes during sleep were not significant in the hippocampus for Bdnf, Camk4, Creb1, and Nr4a1, and no differences were detected between exposed and control SWS groups for any of the genes tested. No significant changes in gene expression were detected in the primary somatosensory cortex during sleep, in contrast with previous studies using longer post-stimulation intervals (>180 min). The experience-dependent induction of multiple plasticity-related genes in the hippocampus during early REM adds experimental support to the synaptic embossing theory.

Identification and characterization of different accessions of itchgrass (Rottboellia cochinchinensis)

Studies were conducted to identify and characterize different accessions of itchgrass. Seeds were collected in the counties of Aramina, Campinas, Dumont, Igarapava, Jaboticabal, and Ribeirao Preto, all in the state of São Paulo, Brazil. Accessions were characterized based on dimensions of their stomata, stomatal index (SI), and length and width of their seed (caryopses and husk). Chromosome number and length also were determined, and accessions were further differentiated using molecular markers (polymerase chain reaction [PCR]). Itchgrass from Ribeirao Preto had much longer and narrower seeds than those from the other locations, and their husks were longer as well. Accessions had similar SIs, both on the abaxial and adaxial leaf surfaces. Stomata from Campinas and Igarapava accessions were longer and wider, whereas those from Dumont and Ribeirao Preto were similar and smaller than all others. The accession from Ribeirao Preto is diploid (2n = 20); the rest are polyploid, with the total length of chromosomes smaller than all others. These differences were confirmed by molecular differentiation (PCR).

Parâmetros bioquímicos sanguíneos, balanço de nitrogênio e metabolizabilidade da energia bruta em suínos alimentados com dietas contendo diferentes balanços eletrolíticos

The aim of this study was to evaluate different dietary electrolyte balance (DEB) on the blood biochemical parameters, nitrogen balances and crude metabolizable energy of swine in the initial phase. Sixteen barrows were used, averaging 27.95 kg of initial weight, allotted individually in metabolic cages in a randomized blocks design with four treatments (DEB of 160, 208, 257 and 305 mEq/kg) and 4 replicates. The blood biochemical parameters analyzed were chloride, potassium, sodium and urea in blood. Urine pH was also evaluated, and the parameters evaluated in nitrogen (N) balance were N intake, fecal N, N excreted in urine, absorbed N, N retention, retained N/absorbed N and total excretion of N. The gross energy digestibility and metabolizibility coefficients were determined, and the respectives values of digestible and metabolizable energy. The values of urinary pH increased (P < 0.01) linearly with increasing levels of DEB, ranging from 6.90 to 8.03. The results for chloride, potassium and nitrogen balances of variables and gross energy were similar (P > 0.05) between the evaluated DEB. A linear increase (P < 0.01) was also observed for sodium concentrations in blood serum due to the increase of DEB, with values of 2.91, 3.03, 3.27 and 3.18 g/l, respectively for the different treatments. Urea levels in blood serum increased linearly (P < 0.01), with values of 26.21, 28.64, 34.32 and 32.89 mg/dl. It was concluded that increasing the dietary electrolyte balance, from 160 to 305 mEq/kg resulted in higher concentrations of urea and sodium in blood serum, and higher pH values in the urine of swine in the initial phase.

Sodium and chloride requirements of young broiler chickens fed corn-soybean diets (one to twenty-one days of age)

Sodium (Na+) and chloride (Cl-) nutritional requirements, dietary electrolyte balance (DEB), and their effects on acid-base balance, litter moisture, and tibial dyschondroplasia (TD) incidence for young broiler chickens were evaluated in two trials. One-day-old Cobb broilers were distributed in a completely randomized design with six treatments, five replicates, and 50 birds per experimental unit. Treatments used in both experiments were a basal diet with 0.10% Na+ (Experiment 1) or Cl- (Experiment 2) supplemented to result in diets with Na+ or Cl- levels of 0.10, 0.15, 0.20, 0.25 ,0.30, or 0.35%, respectively. In Experiment 1, results indicated an optimum Na+ requirement of 0.26%. Sodium levels caused a linear increase in arterial blood gas parameters, indicating an alkalogenic effect of Na+. The hypertrophic area of growth plate in the proximal tibiotarsi decreased with Na+ levels. The TD incidence decreased with increases in dietary Na+. Litter moisture increased linearly with sodium levels. In Experiment 2, the Cl- requirement was estimated as 0.25%. Chloride levels caused a quadratic effect (P ≤ 0.01) on blood gas parameters, with an estimated equilibrium [blood base excess (BE) = 0] at 0.30% of dietary CT-. No Cl- treatment effects (P ≥ 0.05) were observed on litter moisture or TD incidence. The best DEB for maximum performance was 298 to 315 mEq/kg in Experiment 1 and 246 to 264 mEq/kg in Experiment 2. We concluded that the Na+ and Cl- requirements for optimum performance of young broiler chickens were 0.28 and 0.25%, respectively.