RESUMO
BACKGROUND: Chagas disease (CD) continues to be a neglected infectious disease with one of the largest burdens globally. Despite the modest cure rates in adult chronic patients and its safety profile, benznidazole (BNZ) is still the drug of choice. Its current recommended dose is based on nonrandomized studies, and efficacy and safety of the optimal dose of BNZ have been scarcely analyzed in clinical trials. METHODS/DESIGN: MULTIBENZ is a phase II, randomized, noninferiority, double-blind, multicenter international clinical trial. A total of 240 patients with Trypanosoma CD in the chronic phase will be recruited in four different countries (Argentina, Brazil, Colombia, and Spain). Patients will be randomized to receive BNZ 150 mg/day for 60 days, 400 mg/day for 15 days, or 300 mg/day for 60 days (comparator arm). The primary outcome is the efficacy of three different BNZ therapeutic schemes in terms of dose and duration. Efficacy will be assessed according to the proportion of patients with sustained parasitic load suppression in peripheral blood measured by polymerase chain reaction. The secondary outcomes are related to pharmacokinetics and drug tolerability. The follow-up will be 12 months from randomization to end of study participation. Recruitment was started in April 2018. CONCLUSION: This is a clinical trial conducted for the assessment of different dose schemes of BNZ compared with the standard treatment regimen for the treatment of CD in the chronic phase. MULTIBENZ may help to clarify which is the most adequate BNZ regimen in terms of efficacy and safety, predicated on sustained parasitic load suppression in peripheral blood. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03191162. Registered on 19 June 2017.
Assuntos
Doença de Chagas/tratamento farmacológico , Doenças Negligenciadas/parasitologia , Nitroimidazóis/uso terapêutico , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/isolamento & purificação , Adulto , Assistência ao Convalescente , Argentina/epidemiologia , Brasil/epidemiologia , Estudos de Casos e Controles , Doença de Chagas/parasitologia , Doença Crônica , Colômbia/epidemiologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Nitroimidazóis/farmacocinética , Carga Parasitária/estatística & dados numéricos , Segurança , Espanha/epidemiologia , Resultado do Tratamento , Tripanossomicidas/farmacocinética , Trypanosoma cruzi/genéticaRESUMO
AIM: Although feed medicated with antibiotics is widely used in animal production to prevent and treat bacterial infections, the effect of these drugs on nontarget anaerobic bacteria is unknown. We aimed to clarify whether a single exposure of sulphate-reducing bacteria (SRB) from a tilapia pond to oxytetracycline (OTC) concentrations relevant to aquaculture impacts their function, abundance and community structure. METHODS AND RESULTS: To demonstrate changes in SO4(2-) content, SRB abundance, dsrB copy number and SRB diversity, sediment mesocosms were spiked with 5, 25, 50 and 75 mg OTC kg(-1) and examined for 30 days by means of ion chromatography, qPCR, cultivation and fluorescent in situ hybridization (FISH). On day 3, we measured higher SO4(2-) concentrations (ca. two-fold) and a reduction in dsrB copy numbers of approximately 50% in the treatments compared to the controls. After 30 days, a subtle yet measurable enrichment of bacteria from the order Desulfovibrionales occurred in mesocosms receiving ≥ 50 mg OTC kg(-1), notwithstanding that SRB counts decreased two orders of magnitude. OTC was dynamically and reversibly converted into 4-epioxytetracycline and other related compounds in a dose-dependent manner during the experiment. CONCLUSIONS: A single exposure to rather high OTC concentrations triggered functional and structural changes in a SRB community that manifested quickly and persisted for a month. SIGNIFICANCE AND IMPACT OF THE STUDY: This study improves our limited knowledge on the ecotoxicology of antibiotics in anaerobic environments.
Assuntos
Antibacterianos/farmacologia , Bactérias/metabolismo , Biodiversidade , Água Doce/microbiologia , Sedimentos Geológicos/microbiologia , Oxitetraciclina/farmacologia , Sulfatos/metabolismo , Animais , Aquicultura , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Sedimentos Geológicos/química , Hibridização in Situ Fluorescente , OxirreduçãoRESUMO
Variations in the normalized vegetation index (NDVI) for the state of Oaxaca, in southern Mexico, were analyzed in terms of precipitation anomalies for the period 1997-2003. Using 10-day averages in NDVI data, obtained from AVHRR satellite information, the response of six types of vegetation to intra-annual and inter-annual fluctuations in precipitation were examined. The onset and temporal evolution of the greening period were studied in terms of precipitation variations through spectral analysis (coherence and phase). The results indicate that extremely dry periods, such as those observed in 1997 and 2001, resulted in low values of NDVI for much of Oaxaca, while good precipitation periods produced a rapid response (20-30 days of delay) from a stressed to a non-stressed condition in most vegetation types. One of these rapid changes occurred during the transition from dry to wet conditions during the summer of 1998. As in many parts of the tropics and subtropics, the NDVI reflects low frequency variations in precipitation on several spatial scales. Even after long dry periods (2001-2002), the various regional vegetation types are capable of recovering when a good rainy season takes place, indicating that vegetation types such as the evergreen forests in the high parts of Oaxaca respond better to rainfall characteristics (timing, amount) than to temperature changes, as is the case in most mid-latitudes. This finding may be relevant to prepare climate change scenarios for forests, where increases in surface temperature and precipitation anomalies are expected.
Assuntos
Desenvolvimento Vegetal , Chuva , Clima , México , Análise de Componente Principal , Estações do Ano , Árvores/crescimento & desenvolvimentoRESUMO
OBJECTIVE: To evaluate oxidative bursts induced by phorbol myristate acetate in phagocytes at the single-cell level by automated image analysis. STUDY DESIGN: The generation of reactive oxygen species was quantitatively expressed by means of histograms displaying the percentage of cells corresponding to each of the total optical densities measured. RESULTS: Macrophage subpopulations were quantitatively defined. This method allows detailed analysis of the amount of formazan per cell and the sites of deposition of blue precipitate in each cell. CONCLUSION: Image analysis is a reliable quantitative, single-cell assay for studying various cellular characteristics associated with macrophage functions.
Assuntos
Processamento de Imagem Assistida por Computador/métodos , Macrófagos Alveolares/metabolismo , Explosão Respiratória/fisiologia , Animais , Citometria de Fluxo , Corantes Fluorescentes , Macrófagos Alveolares/efeitos dos fármacos , Fagócitos/metabolismo , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
The high-resolution structure of ovine placental lactogen (oPL) and ovine prolactin (oPRL), not yet established in detail, was probed by limited proteolysis with the Glu-specific protease from Staphylococcus aureus V8. While in hGH there were no cleavage sites inside of any of the four alpha-helices, the analysis of the fragments obtained after partial proteolysis of oPL showed a site of cleavage at the putative third helix, suggesting that this helix is partially unwound at this point. The partial proteolysis of the rest of the molecule was compatible with a similar folding pattern for oPL, hGH and pGH, on the basis of the crystal structure of these last hormones. In the case of oPRL, proteolytic cleavage occurred at Glu residues which would be located at the end of the first helix and the beginning of the second in the hGH folding model, suggesting that these helices are shorter in oPRL than in hGH. In order to gain further insight on the folding of these molecules, circular dichroism and intrinsic fluorescence measurements were used to examine the effect of denaturing conditions on oPL and oPRL. After exposure to 6 M guanidine the unfolding of both proteins was completely reversed upon elimination of the denaturing agent. In contrast, exposure to pH 3.0 caused an irreversible decrease in the alpha-helical content in both hormones, most striking for oPL, indicating that this hormone is less stable than oPRL or hGH.
Assuntos
Lactogênio Placentário/química , Prolactina/química , Sequência de Aminoácidos , Animais , Dicroísmo Circular , Humanos , Dados de Sequência Molecular , Lactogênio Placentário/metabolismo , Prolactina/metabolismo , Estrutura Secundária de Proteína , Homologia de Sequência de Aminoácidos , Serina Endopeptidases/metabolismo , Ovinos , Espectrometria de Fluorescência/métodosRESUMO
It has been reported in vitro that during the respiratory burst of phagocytic cells the superoxide anion production per cell shows a negative relation with the cell density. This process has been described as autoregulation. The aim of this work was to analyze the superoxide anion production in thioglycollate-elicited peritoneal macrophage exudates to evaluate the importance of the peritoneal cavity environment in the autoregulation process. 12-O-tetradecanoylphorbol-13-acetate (PMA) was used to stimulate the respiratory burst and superoxide anion production was measured evaluating the intracellular formazan deposits that precipitate as a result of nitro blue tetrazolium (NBT) reduction. We have demonstrated a negative correlation between superoxide anion production and cell density in the peritoneal cavity in macrophages challenged with PMA. The response of individual cells was analyzed by means of an image analyzer, measuring the amount of formazan per cell and cell-size changes during the process of activation. The results revealed that the decrease in individual cell response as a function of higher cell densities were due to a significant increase in the amount of basal reaction macrophages. Concomitantly, the number of reactive cells remained unchanged irrespective of the cell density of the population. A direct correlation between cell size and superoxide anion production was observed. This phenomenon was demonstrated in SENCAR and Balb/c strains. However, macrophages from SENCAR mice showed greater superoxide anion production than those from Balb/c. The differences between strains could be associated to the increased sensitivity to PMA tumor promotion of SENCAR mice. Based on this property, macrophages from SENCAR mice were stimulated with opsonized zymosan, a particulate stimulus that reflects the interaction macrophage-microorganism during the phagocytic process. This data will contribute to the knowledge of infection control. We conclude that variations in basal reaction cells modulates the macrophage activation response when excess macrophages are recruited to the peritoneum. This is demonstrated using different stimuli, thus suggesting that this response may be applied to a wide variety of stimuli-macrophage interactions. The differences between strains may be associated to the increased sensitivity to PMA tumor promotion of SENCAR mice.
Assuntos
Macrófagos Peritoneais/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Animais , Contagem de Células , Tamanho Celular , Processamento de Imagem Assistida por Computador , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos SENCAR , Camundongos Endogâmicos , Explosão Respiratória , Espectrofotometria , Superóxidos/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Sais de Tetrazólio , Tioglicolatos/farmacologia , Zimosan/farmacologiaAssuntos
Aleitamento Materno , Diarreia Infantil/imunologia , Fezes/química , Helmintíase/imunologia , Enteropatias Parasitárias/imunologia , Lactoferrina/análise , Leucócitos/citologia , Testes de Aglutinação , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/imunologia , Criança , Pré-Escolar , Países em Desenvolvimento , Diarreia Infantil/microbiologia , Diarreia Infantil/parasitologia , Helmintíase/diagnóstico , Humanos , Lactente , Enteropatias Parasitárias/diagnóstico , NicaráguaRESUMO
Most developed expression systems rely on the production of fusion proteins or the change of selection marker increasing genetic stability to avoid toxicity of heterologous proteins to Escherichia coli host cells. According to this, we analyzed the effect of the selection marker on the viability and plasmid stability of vectors pYMK5 and pYMK7 that codify neurotrophic factors brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). We also analyzed the influence of two different lac promoter inducers on these parameters. We found that the addition of IPTG to culture medium produced a significant decrease of viability and plasmid stability for both expression vectors compared with values reached with lactose. There was no increase of both parameters when we changed the selection marker, so we can conclude that, in our case, a change of antibiotic does not solve the problem of low plasmid stability values.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Fatores de Crescimento Neural/genética , Plasmídeos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Clonagem Molecular , Escherichia coli/genética , Marcadores Genéticos , Humanos , Óperon Lac , Fatores de Crescimento Neural/metabolismo , Regiões Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
Lime-treated maize husks (LTCH), a by-product of tortilla manufacturing in Mexico, have been shown to decrease plasma LDL-cholesterol levels in guinea-pigs by specific alterations in hepatic cholesterol metabolism. To determine whether LTCH would also lower plasma cholesterol levels in normal and hyperlipidaemic individuals, the fibre content of a typical diet was increased by supplementing free-living subjects in North-West Mexico with cookies containing 450 g LTCH/kg. Normal subjects (n 11) with plasma cholesterol levels of less than 5.7 mmol/l and hypercholesterolaemic subjects (n 12) with plasma cholesterol levels higher than 5.7 mmol/l participated in the study. Plasma glucose, cholesterol, triacylglycerol, LDL-cholesterol and HDL-cholesterol concentrations, LDL:HDL values and blood pressure were determined at baseline and after 6 weeks of supplementation with LTCH. LTCH supplementation significantly lowered the plasma total cholesterol level by 11-15% and LDL-cholesterol by 25%, and improved the LDL:HDL value by 29-33% (P < 0.01) in both normal and hypercholesterolaemic subjects. HDL-cholesterol, triacylglycerol and glucose concentrations did not change. Both groups consumed equal amounts of LTCH per week; individuals showed excellent compliance and good acceptance of the product. Neither group changed their dietary habits during the time of the experiment as determined by 3 d dietary records at baseline and at week 6. We conclude that LTCH supplements are suitable to increase fibre intake and reduce plasma LDL-cholesterol levels in healthy and hypercholesterolaemic subjects in this population.
Assuntos
LDL-Colesterol/sangue , Fibras na Dieta/administração & dosagem , Frutas , Hipercolesterolemia/dietoterapia , Zea mays , Adulto , Estudos de Casos e Controles , Colesterol/sangue , Humanos , Hipercolesterolemia/sangue , Masculino , Cooperação do PacienteRESUMO
BACKGROUND: Psyllium and oat bran have been shown to lower plasma LDL cholesterol levels in different populations. Hypercholesterolemia is prevalent in the Northern part of Mexico and might be associated to dietary habits and sedentary lifestyle. METHODS: Sedentary normal (cholesterol<200 mg/dL) (n=36) and hypercholesterolemic (cholesterol>220 mg/dL) (n=30) men from the Northern part of Mexico aged 20 to 45 years of age participated in an 8-week study to determine the effects of dietary soluble fiber, either psyllium or oat bran, in lowering plasma LDL cholesterol in this population. Fiber was administered by feeding the subjects an amount of cookies (100 g) equivalent to 1.3 or 2.6 g/day of soluble fiber from psyllium or oat bran, respectively. Subjects were randomly allocated to three groups: a control group consuming cookies with wheat bran, a known source of fiber with no cholesterol lowering effects, psyllium, or oat bran. RESULTS: Food frequency questionnaires indicated that subjects from the three groups had similar intakes of foods classified as hypercholesterolemic (p>0.05). Plasma LDL cholesterol concentrations were reduced by an average of 22.6 and 26% in the psyllium and oat bran groups (p<0.001) while a non-significant reduction of 8.4% was observed in the hypercholesterolemic individuals from the control group. No effects on plasma HDL or triglycerides levels were observed among the three dietary treatments except for hypercholesterolemic individuals supplemented with oat bran where a 28% reduction in plasma triglycerides was observed after 8 weeks (p<0.01). CONCLUSION: These results indicate that psyllium and oat bran are efficacious in lowering plasma LDL cholesterol in both normal and hypercholesterolemic individuals from this population.