Photochemical degradation of triclosan: a comparison between different light sources

New emerging contaminants could represent a danger to the environment and Humanity with repercussions not yet known. One of the major worldwide pharmaceutical and personal care productions are antimicrobials products, triclosan, is an antimicrobial agent present in most products. Despite the high removal rate of triclosan present in wastewater treatments, triclosan levels are on the rise in the environment through disposal of wastewater effluent and use of sewage sludge in land application. Regulated in the EC/1272/2008 (annex VI, table 3.1), this compound is considered very toxic to aquatic life and it has been reported that photochemical transformation of triclosan produces dioxins. In the current work it was defined three objectives; determination of the most efficient process in triclosan degradation, recurring to photochemical degradation methods comparing different sources of light; identification of the main by-products formed during the degradation and the study of the influence of the Fenton and photo-Fenton reaction. Photochemical degradation methods such as: photocatalysis under florescent light (UV), photocatalysis under visible light (sunlight), photocatalysis under LEDs, photo-Fenton and Fenton reaction have been compared in this work. The degradation of triclosan was visualized through gas chromatography/mass spectrometry (GC/MS). In this study photo-Fenton reaction has successfully oxidized triclosan to H2O and CO2 without any by-products within 2 hours. Photocatalysis by titanium dioxide (TiO2) under LEDs was possible, having a degradation rate of 53% in an 8 hours essay. The degradation rate of the Fenton reaction, UV light and sunlight showed degradation between 90% and 95%. The results are reported to the data observed without statistic support, since this was not possible during the work period. Hydroquinone specie and 2,4-dichlorophenol by-products were identified in the first hour of photocatalysis by UV. A common compound, possibly identified has C7O4H , was present at the degradation by UV, sunlight and LEDs and was concluded to be a contaminant. In the future more studies in the use of LEDs should be undertaken given the advantages of long durability and low consumption of energy of these lamps and that due to their negative impact on the environment fluorescent lamps are being progressively made unavailable by governments, requiring new solutions to be found. Fenton and photo-Fenton reactions can also be costly processes given the expensive reagents used.

Comparison of the performance of polymerase chain reaction and pp65 antigenemia for the detection of human cytomegalovirus in immunosuppressed patients

INTRODUCTION: Human cytomegalovirus (HCMV) is often reactive in latently infected immunosuppressed patients. Accordingly, HCMV remains one of the most common infections following solid organ and hemopoietic stem cell transplantations, resulting in significant morbidity, graft loss and occasional mortality. The early diagnosis of HCMV disease is important in immunosuppressed patients, since in these individuals, preemptive treatment is useful. The objective of this study was to compare the performance of the in-house qualitative polymerase chain reaction (PCR) and pp65 antigenemia to HCMV infection in immunosuppressed patients in the Hospital de Clínicas of Porto Alegre (HCPA). METHODS: A total of 216 blood samples collected between August 2006 and January 2007 were investigated. RESULTS: Among the samples analyzed, 81 (37.5%) were HCMV-positive by PCR, while 48 (22.2%) were positive for antigenemia. Considering antigenemia as the gold standard, sensitivity, specificity, positive predictive values and negative predictive values for PCR were 87.5%, 76.8%, 51.8% and 95.5% respectively. CONCLUSIONS: These results demonstrated that qualitative PCR has high sensitivity and negative predictive value (NPV). Consequently PCR is especially indicated for the initial diagnosis of HCMV infection. In the case of preemptive treatment strategy, identification of patients at high-risk for HCMV disease is fundamental and PCR can be useful tool.

Caracterização do papel dos genes TYMS e MTR no desenvolvimento de Cancro Colo-Rectal

RESUMO: O cancro colo-rectal (CCR) é um dos cancros que possui maior taxa de mortalidade a nível mundial. Em Portugal esta patologia é responsável pela morte de cerca de 3700 pessoas por ano, sendo que estes números aumentam de ano para ano. Ao longo das últimas décadas o papel das alterações genéticas na etiologia das patologias oncológicas tem vindo a ter cada vez mais um maior destaque. O número de estudos que avaliam a importância de polimorfismos, mutações, alterações na regulação génica e interacções entre genes no desenvolvimento destas patologias tem aumentado exponencialmente. Com o aumento do conhecimento da forma como estas alterações influenciam o desenvolvimento do cancro surgiram os primeiros meios de diagnóstico genético, levando assim a uma alteração da forma como são encarados o diagnóstico e a prevenção destas doenças. No CCR as formas hereditárias com alterações genéticas inequivocamente identificadas representam apenas 5% dos casos. Existem cerca de 25% que representam formas hereditárias para as quais ainda não foram estabelecidos os padrões de alterações genéticas subjacentes. Desta forma, estudos que venham contribuir para um maior conhecimento dos mecanismos moleculares responsáveis pelo aumento da susceptibilidade dos indivíduos para o desenvolvimento de CCR são extremamente importantes. O CCR é uma patologia multifactorial, onde factores genéticos interagem com factores ambientais no surgimento e desenvolvimento da doença. Assim, torna-se essencial integrar o estudo das alterações genéticas no contexto ambiental onde os indivíduos em estudo se encontram. No caso desta patologia um dos principais factores ambientais estudado é a nutrição. Vários estudos têm sido realizados ao longo dos últimos anos de forma a compreender como pode a ingestão dos nutrientes influenciar o desenvolvimento de CCR e de que forma interage com as alterações genéticas individuais. O ciclo do folato é um dos processos metabólicos onde o papel da nutrição em interacção com alterações genéticas mais tem sido estudado nos últimos anos. Deste cruzamento entre o estudo das alterações genéticas e ambientais surge a Nutrigenética. O conjunto de estudos da presente tese tem como objectivo aumentar o conhecimento do papel das alterações em genes do ciclo do folato, em interacção com factores nutricionais e de estilo de vida, não só no desenvolvimento de CCR, mas também de outra patologia do tracto gastrointestinal, a Doença de Crohn (DC), uma doença inflamatória muitas vezes associada como factor de risco para o desenvolvimento de CCR. Este estudo debruçou-se essencialmente no estudo dos genes timidilato sintetase (TYMS) e metionina sintetase (MTR) em populações com CCR e DC, bem como no padrão nutricional destas populações com particular incidência nos nutrientes envolvidos no ciclo do folato (folato, metionina, vitamina B6, vitamina B12). Analisando o conjunto de resultados obtidos para os estudos do CCR podemos concluir que quer a TYMS quer a MTR possuem um papel relevante na susceptibilidade para desenvolver esta patologia, assim como têm destaque no funcionamento do ciclo celular durante o processo oncogénico. Os resultados demonstram que os factores que levam a uma menor disponibilidade de grupos metil no ciclo de folato (baixos níveis de folato, alteração da actividade de MTR, elevada expressão de TYMS) constituem factores de risco, muito provavelmente por contribuírem para uma desregulação dos níveis de metionina disponível para a metilação do DNA da célula. Demonstram ainda que em células tumorais ocorrem alterações na regulação do ciclo do folato de forma a favorecer a síntese de DNA em detrimento da metilação do mesmo, alterando para isso a expressão dos genes de forma a que o fluxo de grupos metil provenientes do folato sejam encaminhados para a enzima TYMS. O polimorfismo de deleção 6pb da TYMS surge como um factor de diagnóstico e de prognóstico de CCR para a população portuguesa. Dos factores nutricionais analisados apenas o folato aparenta ter um papel relevante na modelação do risco de desenvolver CCR. Na doença de Crohn (DC) podemos verificar que a homocisteína e o seu metabolismo poderão contribuir para o aparecimento e desenvolvimento da patologia. O aumento da homocisteína poderá ser o responsável por um aumento da resposta auto-imune do organismo, promovendo o aparecimento da DC. O polimorfismo A2756G MTR desempenha um papel preponderante como factor de diagnóstico da DC, tendo sido associado pela primeira vez a esta patologia. Tem também um papel importante no desenvolvimento da doença, uma vez que está associado a uma idade de diagnóstico mais baixa, sugerindo assim que o desenvolvimento da doença ocorre de forma mais precoce. Concluindo, com este estudo pensamos ter contribuído para um melhor entendimento do papel do ciclo do folato no desenvolvimento de CCR e DC, sendo um ponto de partida para futuras investigações que possam revelar cada vez melhor as complexas interacções metabólicas desta via e a sua influência nas patologias estudadas. Do nosso estudo destacamos a importância de uma análise global das várias etapas do ciclo do folato para que se possa compreender a dinâmica que se estabelece no desenvolvimento destas patologias, podendo diversas alterações, quer a nível genético quer a nível nutricional, exercerem efeitos diferentes consoante o estado dos restantes intervenientes do ciclo do folato. Acreditamos que no futuro este estudo permitirá que o conhecimento do ciclo do folato tenha cada vez mais uma relevância fundamental a nível de diagnóstico e terapêutica destas patologias.------------ ABSTRACT: Colorectal Cancer (CRC) is one of the cancers that have a higher rate of mortality worldwide. In Portugal this pathology is responsible for the deaths of about 3700 people per year, and these numbers increase each year. Over the past few decades the role of genetic changes in the etiology of oncological pathologies has had an increasingly greater emphasis. The number of studies that evaluate the importance of polymorphisms, mutations, changes in gene regulation and gene interactions in the development of these diseases has increased exponentially. With the increased knowledge of how these changes influence the development of cancer, appeared the first means for genetic diagnostic, leading to a change in the way diagnosis is seen and in the prevention of these diseases. In CRC the hereditary forms with clearly identified genetic changes represent only 5% of cases. There are about 25% representing hereditary forms for which the patterns of genetic changes haven’t been established. In this way, studies that will contribute to a greater understanding of the molecular mechanisms responsible for increased susceptibility of individuals to the CRC development are extremely important. CRC is a multifactorial pathology, where genetic factors interact with environmental factors in the emergence and development of the disease.Thus, it is essential to integrate the study of genetic changes in the environmental context of the individuals under study. In the case of this pathology one of the main environmental factors studied is nutrition. Several studies have been conducted over the past few years in order to understand how the intake of nutrients can influence the development of CRC and how nutrients interact with the individual genetic changes. The folate cycle is one of the metabolic processes where the role of nutrition in interaction with genetic alterations has been studied in recent years. This cross between the study of genetic and environmental changes developed Nutrigenetics. The set of studies of this thesis aims to increase awareness of the role of changes in genes of the folate cycle, in interaction with nutritional factors and lifestyle, not only in the development of CRC, but also of another pathology of the gastrointestinal tract, Crohn's disease (CD), an inflammatory disease often associated as a risk factor for the development of CRC. This study dealt mainly in the study of genes thymidylate synthase (TYMS) and methionine synthase (MTR) in populations with CRC and CD, as well as in the nutritional pattern of these populations with particular focus on nutrients involved in the folate cycle (folate, methionine, vitamin B6, vitamin B12). Analyzing the results obtained for the CRC studies we conclude that either the MTR TYMS have a relevant role in susceptibility to develop this pathology, and have an important role in the functioning of the cell cycle during oncogenesis. The results show that the factors that lead to a lower availability of methyl groups in folate cycle (low levels of folate, change the activity of MTR, high expression of TYMS) constitute risk factors, most likely by contribute to a dysregulation of methionine levels available for DNA methylation of the cell. Our results also demonstrate that in tumor cells occur changes in the regulation of the folate cycle in order to promote the synthesis of DNA, to the detriment of methylation of the same by changing the expression of genes so that the methyl groups from folate are forwarded to the TYMS enzyme reaction. The deletion polymorphism 6bp of TYMS emerges as a diagnostic and prognostic factor of CCR for the Portuguese population. Nutritional factors analyzed only folate appears to have a major role in modulating the risk of developing CCR.In Crohn’s disease (CD) we can check that homocysteine and its metabolism may contribute to the emergence and development of this pathology. Increased homocysteine may be responsible for an increase in the body's autoimmune response, promoting the emergence of CD. The polymorphism A2756G MTR plays a leading role as a factor of diagnosis of DC, having been associated with this pathology for the first time. It also has an important role in the development of the disease, since it is associated with a lower diagnostic age, suggesting that the development of the disease occurs earlier. In conclusion, our study has contributed to a better understanding of the role of folate cycle in the development of CRC and CD, being a starting point for future research that may prove increasingly complex metabolic interactions in this via and its influence on the pathologies studied. In our study we highlight the importance of a comprehensive analysis of the various steps of the folate cycle in order to understand the dynamics that settles in the development of these pathologies, and a number of amendments, whether at the genetic level or at the nutritional level, exercise different effects depending on the stage of the remaining participants in the folate cycle. We believe that in the future this study will allow the knowledge of folate cycle to have increasingly a fundamental relevance at the level of diagnosis and treatment of these diseases.

Diagnosis of human herpesvirus 6B primary infection by polymerase chain reaction in young children with exanthematic disease

INTRODUCTION: Exanthem subitum is a classical rash disease of early childhood caused by human herpesvirus 6B (HHV-6B). However, the rash is frequently misdiagnosed as that of either measles or rubella. METHODS: In this study, a nested multiplex polymerase chain reaction (PCR) was used to diagnose HHV-6B primary infection, differentiate it from infections caused by HHV-6A and compare it to antibody avidity tests. The samples were separated into case group and control group according to the results of the indirect immunofluorescence assay (IFA) technique. RESULTS: From the saliva samples analyzed, HHV-6A DNA was detected in 3.2% of the case group and in 2.6% of the control group. Regarding HHV-6B, PCR detected viral DNA in 4.8% of the case group and in 1.3% of the control group. Among the serum samples studied, a frequency of 1.7% was determined for HHV-6A in the case group and 1.2% in the control group. PCR did not detect HHV-6B DNA in serum samples. The sensitivity and specificity of the PCR technique ranged from 0% to 4.8% and 97.5% to 100%, respectively, compared to IFA. CONCLUSIONS: The PCR technique was not suitable for diagnosing primary infection by HHV-6B in children with exanthematic disease and should not substitute the IFA.

Lessons from the epidemiological surveillance program, during the influenza A (H1N1) virus epidemic, in a reference university hospital of Southeastern Brazil

INTRODUCTION: The case definition of influenza-like illness (ILI) is a powerful epidemiological tool during influenza epidemics. METHODS: A prospective cohort study was conducted to evaluate the impact of two definitions used as epidemiological tools, in adults and children, during the influenza A H1N1 epidemic. Patients were included if they had upper respiratory samples tested for influenza by real-time reverse transcriptase polymerase chain reaction during two periods, using the ILI definition (coughing + temperature > 38ºC) in period 1, and the definition of severe acute respiratory infection (ARS) (coughing + temperature > 38ºC and dyspnoea) in period 2. RESULTS: The study included 366 adults and 147 children, covering 243 cases of ILI and 270 cases of ARS. Laboratory confirmed cases of influenza were higher in adults (50%) than in children (21.6%) ( p < 0.0001) and influenza infection was more prevalent in the ILI definition (53%) than ARS (24.4%) (p < 0.0001). Adults reported more chills and myalgia than children (p = 0.0001). Oseltamivir was administered in 58% and 46% of adults and children with influenza A H1N1, respectively. The influenza A H1N1 case fatality rate was 7% in adults and 8.3% in children. The mean time from onset of illness until antiviral administration was 4 days. CONCLUSIONS: The modification of ILI to ARS definition resulted in less accuracy in influenza diagnosis and did not improve the appropriate time and use of antiviral medication.

Could leprosy reaction episodes be exacerbated by oral infections?

INTRODUCTION: This study evaluated whether leprosy reactions could be associated with oral infection. METHODS: Leprosy patients (n = 38) with (Group I) and without (Group II) oral infections were selected. Reactions were identified from the clinical and histopathological features associated with serum C-reactive protein (CRP) and10kDa interferon-gamma-induced protein (IP-10) levels, determined before and after elimination of the foci of infection. RESULTS: Group I presented more reactions than group II did, and improvement of the reactions after dental treatment. Serum CRP and IP-10 did not differ before and after the dental treatment, but differed between the groups. CONCLUSIONS: Oral infection could be an exacerbating factor in leprosy reactions.

Comparison among three polymerase chain reaction assays on detection of DNA from Leishmania in biological samples from patients with american cutaneous leishmaniasis

INTRODUCTION: The study analyzed positivity of polymerase chain reaction (PCR) on detection of DNA from Leishmania in patients' samples. METHODS: Extracted DNA was submitted to L150/L152, 13Y/13Z, and seminested PCR (snPCR). RESULTS: Results were evidenced by bands of approximately 120, 720, and 670 bp for L150/L152, 13Y/13Z, and snPCR, respectively. L150/L152, 13Y/13Z, and snPCR positivity indexes were 76.9, 56.4, and 9.2 (p>0.05), respectively, for suspected and 93.7, 68.7, and 84.4 (p<0.05), respectively, for confirmed. CONCLUSIONS: Preliminary results showed that these assays, mainly L150/L152 and snPCR, can detect Leishmania DNA and carry potential on laboratory diagnosis of leishmaniasis.

Avaliação da monitorização diária da proteína C-Reativa no doente crítico

RESUMO: O objectivo desta Tese de Doutoramento foi estudar o valor da Proteína CReactiva(PCR) como marcador de infecção e sepsis. Por definição, um marcador da infecção não está presente se o doente não está infectado, deve aparecer concomitantemente ou idealmente preceder a instalação da infecção, deve desaparecer com a instituição de terapêutica antimicrobiana adequada e permanecer elevado se a infecção for refractária ao tratamento. Do ponto de vista biológico, a PCR é o protótipo das proteínas de fase aguda, com uma marcada elevação da sua concentração sérica em resposta a diversos estímulos inflamatórios em particular infecções bacterianas. A sua concentração sérica depende apenas da intensidade do estímulo e da velocidade de síntese hepática, não sendo influenciada por nenhum factor ou tratamento a não ser que este tenha influência directa sobre o estímulo desencadeante, o que a torna um marcador de infecção com grande potencial. Nesta Tese comparou-se a PCR com marcadores clássicos de infecção, temperatura e contagem leucocitária, em diversas situações clínicas analisando doentes com infecções documentadas e doentes controlos, sem infecção. Globalmente os resultados dos trabalhos desta Tese mostram que a PCR é um bom marcador de infecção de acordo com a definição previamente apresentada. Em conjunto com a restante avaliação clínica e laboratorial, a monitorização diária da PCR nos doentes sem infecção mostrou ser útil como sentinela da infecção, isto é, apresenta valores baixos nos doentes sem infecção e sobe precocemente nos doentes que desenvolvem uma infecção. Nos doentes com infecção documentada revelou um ser bom marcador de resposta à terapêutica e evolução clínica, diminuindo naqueles que melhoravam e persistindo elevada nos que tinham mau prognóstico, bem assim como identificar diferentes perfis evolutivos. Em suma, a monitorização diária da PCR mostrou utilidade ao longo de todo o internamento na Unidade de Cuidados Intensivos, quer na presença quer na ausência de infecção. Deste todo, a monitorização diária da PCR pode a possibilitar uma utilização mais racional e judiciosa da terapêutica antimicrobiana, contribuindo dessa forma para uma diminuição da toxicidade e da pressão antibiótica, menor risco de emergência de resistências e finalmente diminuição dos custos. Uma vez que, os doentes internados nas Unidades de Cuidados Intensivos apresentam as mesmas doenças que os restantes doentes admitidos no hospital apenas se distinguindo pela sua maior gravidade, poder-se-á extrapolar que a PCR também é potencialmente um bom marcador de infecção nestes doentes. ----------------ABSTRACT: The aim of this PhD Thesis was to assess the value of C-Reactive Protein (CRP) as a marker of infection and sepsis. A marker of infection should be absent in a non-infected patient, should increase alongside or ideally precede the development of an infection, and finally should assess the therapeutic response, that is to say decrease or even disappear with adequate antimicrobial therapy or on the opposite remain elevated if the infection is refractory to the prescribed treatment. The biology of CRP makes it the prototype of acute phase proteins, with marked and sharp elevations of its serum concentration in response to several inflammatory stimulus in particular bacterial infections. Besides, CRP level depends only of the intensity of the stimulus and the rate of hepatic synthesis. Its concentration is not modified by any therapy or intervention. Only those interventions affecting the inflammatory process responsible for the acute phase reaction can change the CRP level. These properties make CRP a potentially good marker of infection. In this Thesis the value of CRP was studied in comparison to traditional markers of infection, like temperature and white cell count, in different clinical situations analysing patients with documented infections and a control group without infection. The aggregated results of the analysis presented in this Thesis illustrate that CRP could be used as a marker of infection. In conjunction with other clinical and laboratory manifestations of sepsis, daily CRP measurement in patients without infection was useful in prediction of infection as its concentration remains low in patients without infection whereas if an infection appears its levels raise markedly. In addition, in patients with documented infections CRP was useful as a marker of therapeutic response and follow-up, with marked decreases in patients with good outcome and remaining elevated in those with poor prognosis, as well as the recognition of different patterns of evolution. In summary, daily CRP measurement was helpful in critical ill patients along the entire Intensive Care Unit stay, both in the presence and in the absence of infection. As a result, daily CRP measurement can assure a better and more rational use of antibiotics and consequently contribute to a decrease in the antibiotic toxicity and demand, reducing the risks of emergence of resistant strains aas well as costs. Provided that patients admitted to an Intensive Care Unit presented the same clinical diagnosis as those admitted to the wards but with higher severity, one can speculate that CRP is also a potentially good marker of infection in these of patients.

Structured products in the current low interest rate environment

Directed Research Internship

Analysis of metabolic flux distributions in relation to the extracellular environment in Avian cells

Continuous cell lines that proliferate in chemically defined and simple media have been highly regarded as suitable alternatives for vaccine production. One such cell line is the AG1.CR.pIX avian cell line developed by PROBIOGEN. This cell line can be cultivated in a fully scalable suspension culture and adapted to grow in chemically defined, calf serum free, medium [1]–[5]. The medium composition and cultivation strategy are important factors for reaching high virus titers. In this project, a series of computational methods was used to simulate the cell’s response to different environments. The study is based on the metabolic model of the central metabolism proposed in [1]. In a first step, Metabolic Flux Analysis (MFA) was used along with measured uptake and secretion fluxes to estimate intracellular flux values. The network and data were found to be consistent. In a second step, Flux Balance Analysis (FBA) was performed to access the cell’s biological objective. The objective that resulted in the best predicted results fit to the experimental data was the minimization of oxidative phosphorylation. Employing this objective, in the next step Flux Variability Analysis (FVA) was used to characterize the flux solution space. Furthermore, various scenarios, where a reaction deletion (elimination of the compound from the media) was simulated, were performed and the flux solution space for each scenario was calculated. Growth restrictions caused by essential and non-essential amino acids were accurately predicted. Fluxes related to the essential amino acids uptake and catabolism, the lipid synthesis and ATP production via TCA were found to be essential to exponential growth. Finally, the data gathered during the previous steps were analyzed using principal component analysis (PCA), in order to assess potential changes in the physiological state of the cell. Three metabolic states were found, which correspond to zero, partial and maximum biomass growth rate. Elimination of non-essential amino acids or pyruvate from the media showed no impact on the cell’s assumed normal metabolic state.

Polymerase chain reaction and nested-PCR approaches for detecting Cryptosporidium in water catchments of water treatment plants in Curitiba, State of Paraná, Brazil

Introduction Cryptosporidium is an important protozoan cause of waterborne disease worldwide of concern to public health authorities. To prevent outbreaks of cryptosporidiosis, the monitoring of this parasite in drinking water is necessary. In the present work, the polymerase chain reaction (PCR) and nested-PCR techniques were used to detect Cryptosporidium in raw water from catchment points of four water treatment plants (WTP) in Curitiba, Paraná, Brazil. Methods First, DNA extraction techniques were tested in samples containing decreasing amount of oocysts in reagent water, and PCR and nested-PCR with specific primers for 18SSU rDNA of Cryptosporidium were conducted to determine their sensitivity. In reagent water, a commercial extraction kit provided the best analytical sensitivity, and PCR and nested-PCR allowed the detection of five and two oocysts, respectively, with the primers XIAOR/XIAOF and XIAO1F/XIAO2R. Results In the spiking experiments, only the PCR with the primers AWA995F/AWA1206R was successful at detecting concentrations of 0.1 oocysts/mL. Two catchments samples of raw water and/or water sludge from four WTPs were contaminated with Cryptosporidium. Conclusions The application of the techniques to monitor Cryptosporidium in water and detect contamination in water catchments of WTPs in Curitiba are discussed in the present work.

The thermal effects on the methanol-to-olefins reaction: A modelling and experimental approach

With the projection of an increasing world population, hand-in-hand with a journey towards a bigger number of developed countries, further demand on basic chemical building blocks, as ethylene and propylene, has to be properly addressed in the next decades. The methanol-to-olefins (MTO) is an interesting reaction to produce those alkenes using coal, gas or alternative sources, like biomass, through syngas as a source for the production of methanol. This technology has been widely applied since 1985 and most of the processes are making use of zeolites as catalysts, particularly ZSM-5. Although its selectivity is not especially biased over light olefins, it resists to a quick deactivation by coke deposition, making it quite attractive when it comes to industrial environments; nevertheless, this is a highly exothermic reaction, which is hard to control and to anticipate problems, such as temperature runaways or hot-spots, inside the catalytic bed. The main focus of this project is to study those temperature effects, by addressing both experimental, where the catalytic performance and the temperature profiles are studied, and modelling fronts, which consists in a five step strategy to predict the weight fractions and activity. The mind-set of catalytic testing is present in all the developed assays. It was verified that the selectivity towards light olefins increases with temperature, although this also leads to a much faster catalyst deactivation. To oppose this effect, experiments were carried using a diluted bed, having been able to increase the catalyst lifetime between 32% and 47%. Additionally, experiments with three thermocouples placed inside the catalytic bed were performed, analysing the deactivation wave and the peaks of temperature throughout the bed. Regeneration was done between consecutive runs and it was concluded that this action can be a powerful means to increase the catalyst lifetime, maintaining a constant selectivity towards light olefins, by losing acid strength in a steam stabilised zeolitic structure. On the other hand, developments on the other approach lead to the construction of a raw basic model, able to predict weight fractions, that should be tuned to be a tool for deactivation and temperature profiles prediction.

Evaluation of parasitological examination, kDNA polymerase chain reaction and rK39-based immunochromatography for the diagnosis of visceral leishmaniasis in seropositive dogs from the screening-culling program in Brazil

Introduction Dogs play a primary role in the zoonotic cycle of visceral leishmaniasis (VL). Therefore, the accurate diagnosis of infected dogs, primarily asymptomatic dogs, is crucial to the efficiency of VL control programs. Methods We investigated the agreement of four diagnostic tests for canine visceral leishmaniasis (CVL): parasite detection, either after myeloculture or by direct microscopic examination of tissue imprints; kinetoplast-deoxyribonucleic acid-polymerase chain reaction (kDNA-PCR); and an immunochromatographic test (ICT). An enzyme-linked immunosorbent assay (ELISA) and an indirect immunofluorescence test (IFAT), both of which were adopted as part of the screening-culling program in Brazil, were used as reference tests. Our sample set consisted of 44 seropositive dogs, 25 of which were clinically asymptomatic and 19 were symptomatic for CVL according to ELISA-IFAT. Results The highest and lowest test co-positivities were observed for ICT (77.3%) and myeloculture (58.1%), respectively. When analyzed together, the overall percentage of co-positive tests was significantly higher for the symptomatic group compared to the asymptomatic group. However, only ICT was significantly different based on the results of a separate analysis per test for each group of dogs. The majority (93.8%) of animals exhibited at least one positive test result, with an average of 2.66 positive tests per dog. Half of the symptomatic dogs tested positive for all four tests administered. Conclusions The variability between test results reinforces the need for more efficient and reliable methods to accurately diagnose canine VL, particularly in asymptomatic animals.

High visceral leishmaniasis mortality rate in Barra Mansa, a new area of visceral leishmaniasis transmission in the State of Rio de Janeiro, Brazil

Introduction Nine cases of visceral leishmaniasis occurred recently in Barra Mansa, State of Rio de Janeiro, with a high mortality rate. Methods We reviewed the medical records of the patients. Results Eight were male; 7 were adults. Patients who died progressed to death quickly and presented with aggravating factors: systemic steroid therapy before diagnosis, bleeding, severe liver involvement, infection, and/or refusal to receive transfusion. Conclusions We warn clinicians to be aware of the emergence of visceral leishmaniasis in new areas and to keep in mind the possibility of atypical clinical pictures and aggravating factors, so timely diagnosis can be made and prompt and adequate treatment can be initiated.

Leishmania, Babesia and Ehrlichia in urban pet dogs: co-infection or cross-reaction in serological methods?

INTRODUCTION: The present study was designed to assess the occurrence of co-infection or cross-reaction in the serological techniques used for detecting the anti-Leishmania spp., -Babesia canis vogeli and -Ehrlichia canis antibodies in urban dogs from an area endemic to these parasites. METHODS: The serum samples from dogs were tested for the Babesia canis vogeli strain Belo Horizonte antigen and Ehrlichia canis strain São Paulo by immunofluorescence antibody test (IFAT) and by anti-Leishmania immunoglobulin G (IgG) antibody detection to assess Leishmania infection. We used the following four commercial kits for canine visceral leishmaniasis: ELISA, IFAT, Dual Path Platform (DPP) (Bio Manguinhos(r)/FIOCRUZ/MS) and a rK39 RDT (Kalazar Detect Canine Rapid Test; Inbios). RESULTS : Of 96 serum samples submitted to serological assays, 4 (4.2%) were positive for Leishmania as determined by ELISA; 12 (12.5%), by IFAT; 14 (14.6%) by rK39 RDT; and 20 (20.8%), by DPP. Antibodies against Ehrlichia and Babesia were detected in 23/96 (23.9%) and 30/96 (31.2%) samples, respectively. No significant association was identified between the results of tests for detecting Babesia or Ehrlichia and those for detecting Leishmania (p-value>0.05). CONCLUSIONS: In the present study, we demonstrated co-infection with Ehrlichia or Babesia and Leishmania in dogs from Minas Gerais (Brazil); we also found that the serological tests that were used did not cross-react.