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OBJECTIVE: To evaluate associations of wildfire fine particulate matter ≤2.5 mm in diameter (PM2.5) with diabetes across multiple countries and territories. RESEARCH DESIGN AND METHODS: We collected data on 3,612,135 diabetes hospitalizations from 1,008 locations in Australia, Brazil, Canada, Chile, New Zealand, Thailand, and Taiwan during 2000-2019. Daily wildfire-specific PM2.5 levels were estimated through chemical transport models and machine-learning calibration. Quasi-Poisson regression with distributed lag nonlinear models and random-effects meta-analysis were applied to estimate associations between wildfire-specific PM2.5 and diabetes hospitalization. Subgroup analyses were by age, sex, location income level, and country or territory. Diabetes hospitalizations attributable to wildfire-specific PM2.5 and nonwildfire PM2.5 were compared. RESULTS: Each 10 µg/m3 increase in wildfire-specific PM2.5 levels over the current day and previous 3 days was associated with relative risks (95% CI) of 1.017 (1.011-1.022), 1.023 (1.011-1.035), 1.023 (1.015-1.032), 0.962 (0.823-1.032), 1.033 (1.001-1.066), and 1.013 (1.004-1.022) for all-cause, type 1, type 2, malnutrition-related, other specified, and unspecified diabetes hospitalization, respectively. Stronger associations were observed for all-cause, type 1, and type 2 diabetes in Thailand, Australia, and Brazil; unspecified diabetes in New Zealand; and type 2 diabetes in high-income locations. An estimate of 0.67% (0.16-1.18%) and 1.02% (0.20-1.81%) for all-cause and type 2 diabetes hospitalizations were attributable to wildfire-specific PM2.5. Compared with nonwildfire PM2.5, wildfire-specific PM2.5 posed greater risks of all-cause, type 1, and type 2 diabetes and were responsible for 38.7% of PM2.5-related diabetes hospitalizations. CONCLUSIONS: We show the relatively underappreciated links between diabetes and wildfire air pollution, which can lead to a nonnegligible proportion of PM2.5-related diabetes hospitalizations. Precision prevention and mitigation should be developed for those in advantaged communities and in Thailand, Australia, and Brazil.
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Diabetes Mellitus , Hospitalización , Material Particulado , Incendios Forestales , Humanos , Hospitalización/estadística & datos numéricos , Material Particulado/análisis , Material Particulado/efectos adversos , Masculino , Australia/epidemiología , Persona de Mediana Edad , Femenino , Diabetes Mellitus/epidemiología , Anciano , Tailandia/epidemiología , Nueva Zelanda/epidemiología , Brasil/epidemiología , Canadá/epidemiología , Taiwán/epidemiología , Adulto , Exposición a Riesgos Ambientales/efectos adversos , Exposición a Riesgos Ambientales/estadística & datos numéricosRESUMEN
Exposure to ambient ozone (O3) is linked to increased mortality risks from various diseases, but epidemiological investigations delving into its potential implications for cancer mortality are limited. We aimed to examine the association between short-term O3 exposure and site-specific cancer mortality and investigate vulnerable subgroups in Brazil. In total 3,459,826 cancer death records from 5570 Brazilian municipalities between 2000 and 2019, were included. Municipal average daily O3 concentration was calculated from a global estimation at 0.25°×0.25° spatial resolution. The time-stratified case-crossover design was applied to assess the O3-cancer mortality association. Subgroup analyses by age, sex, season, time-period, region, urban hierarchy, climate classification, quantiles of GDP per capita and illiteracy rates were performed. A linear and non-threshold exposure-response relationship was observed for short-term exposure to O3 with cancer mortality, with a 1.00% (95% CI: 0.79%-1.20%) increase in all-cancer mortality risks for each 10-µg/m3 increment of three-day average O3. Kidney cancer was most strongly with O3 exposure, followed by cancers of the prostate, stomach, breast, lymphoma, brain and lung. The associated cancer risks were relatively higher in the warm season and in southern Brazil, with a decreasing trend over time. When restricting O3 concentration to the national minimum value during 2000-2019, a total of 147,074 (116,690-177,451) cancer deaths could be avoided in Brazil, which included 17,836 (7014-28,653) lung cancer deaths. Notably, these associations persisted despite observed adaptation within the Brazilian population, highlighting the need for a focus on incorporating specific measures to mitigate O3 exposure into cancer care recommendations.
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Although some studies have found that short-term PM2.5 exposure is associated with lung cancer deaths, its impact on other cancer sites is unclear. To answer this research question, this time-stratified case-crossover study used individual cancer death data between January 1, 2000, and December 31, 2019, extracted from the Brazilian mortality information system to quantify the associations between short-term PM2.5 exposure and cancer mortality from 25 common cancer sites. Daily PM2.5 concentration was aggregated at the municipality level as the key exposure. The study included a total of 34,516,120 individual death records, with the national daily mean PM2.5 exposure 15.3 (SD 4.3) µg/m3. For every 10-µg/m3 increase in three-day average PM2.5 exposure, the odds ratio (OR) for all-cancer mortality was 1.04 (95% CI 1.03-1.04). Apart from all-cancer deaths, PM2.5 exposure may impact cancers of oesophagus (1.04, 1.00-1.08), stomach (1.05, 1.02-1.08), colon-rectum (1.04, 1.01-1.06), lung (1.04, 1.02-1.06), breast (1.03, 1.00-1.06), prostate (1.07, 1.04-1.10), and leukaemia (1.05, 1.01-1.09). During the study period, acute PM2.5 exposure contributed to an estimated 1,917,994 cancer deaths, ranging from 0 to 6,054 cases in each municipality. Though there has been a consistent downward trend in PM2.5-related all-cancer mortality risks from 2000 to 2019, the impact remains significant, indicating the continued importance of cancer patients avoiding PM2.5 exposure. This nationwide study revealed a notable association between acute PM2.5 exposure and heightened overall and site-specific cancer mortality for the first time to our best knowledge. The findings suggest the importance of considering strategies to minimize such exposure in cancer care guidelines. ENVIRONMENTAL IMPLICATION: The 20-year analysis of nationwide death records in Brazil revealed that heightened short-term exposure to PM2.5 is associated with increased cancer mortality at various sites, although this association has gradually decreased over time. Despite the declining impact, the research highlights the persistent adverse effects of PM2.5 on cancer mortality, emphasizing the importance of continued research and preventive measures to address the ongoing public health challenges posed by air pollution.
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Contaminantes Atmosféricos , Exposición a Riesgos Ambientales , Neoplasias , Material Particulado , Humanos , Material Particulado/toxicidad , Material Particulado/análisis , Brasil/epidemiología , Neoplasias/mortalidad , Exposición a Riesgos Ambientales/efectos adversos , Contaminantes Atmosféricos/toxicidad , Contaminantes Atmosféricos/análisis , Contaminantes Atmosféricos/efectos adversos , Masculino , Femenino , Estudios Cruzados , Persona de Mediana Edad , Anciano , AdultoRESUMEN
Enormous health burden has been associated with air pollution and its effects continue to grow. However, the impact of air pollution on labour productivity at the population level is still unknown. This study assessed the association between premature death due to PM2.5 exposure and the loss of productivity-adjusted life years (PALYs), in Brazil. We applied a novel variant of the difference-in-difference (DID) approach to assess the association. Daily all-cause mortality data in Brazil were collected from 2000-2019. The PALYs lost increased by 5.11% (95% CI: 4.10-6.13%), for every 10 µg/m3 increase in the 2-day moving average of PM2.5. A total of 9,219,995 (95% CI: 7,491,634-10,921,141) PALYs lost and US$ 268.05 (95% CI: 217.82-317.50) billion economic costs were attributed to PM2.5 exposure, corresponding to 7.37% (95% CI: 5.99-8.73%) of the total PALYs lost due to premature death. This study also found that 5,005,306 PALYs could be avoided if the World Health Organization (WHO) air quality guideline (AQG) level was met. In conclusion, this study demonstrates that ambient PM2.5 exposure is associated with a considerable labour productivity burden relating to premature death in Brazil, while over half of the burden could be prevented if the WHO AQG was met. The findings highlight the need to reduce ambient PM2.5 levels and provide strong evidence for the development of strategies to mitigate the economic impacts of air pollution.
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Contaminación del Aire , Brasil/epidemiología , Años de Vida Ajustados por Calidad de Vida , Material ParticuladoRESUMEN
BACKGROUND: Wildfire imposes a high mortality burden on Brazil. However, there is a limited assessment of the health economic losses attributable to wildfire-related fine particulate matter (PM2.5). METHODS: We collected daily time-series data on all-cause, cardiovascular, and respiratory mortality from 510 immediate regions in Brazil during 2000-2016. The chemical transport model GEOS-Chem driven with Global Fire Emissions Database (GFED), in combination with ground monitored data and machine learning was used to estimate wildfire-related PM2.5 data at a resolution of 0.25°â×â0.25°. A time-series design was applied in each immediate region to assess the association between economic losses due to mortality and wildfire-related PM2.5 and the estimates were pooled at the national level using a random-effect meta-analysis. We used a meta-regression model to explore the modification effect of GDP and its sectors (agriculture, industry, and service) on economic losses. RESULTS: During 2000-2016, a total of US$81.08 billion economic losses (US$5.07 billion per year) due to mortality were attributable to wildfire-related PM2.5 in Brazil, accounting for 0.68% of economic losses and equivalent to approximately 0.14% of Brazil's GDP. The attributable fraction (AF) of economic losses due to wildfire-related PM2.5 was positively associated with the proportion of GDP from agriculture, while negatively associated with the proportion of GDP from service. CONCLUSION: Substantial economic losses due to mortality were associated with wildfires, which could be influenced by the agriculture and services share of GDP per capita. Our estimates of the economic losses of mortality could be used to determine optimal levels of investment and resources to mitigate the adverse health impacts of wildfires.
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Contaminantes Atmosféricos , Contaminación del Aire , Incendios , Incendios Forestales , Brasil/epidemiología , Material Particulado/efectos adversos , Material Particulado/análisis , Aprendizaje Automático , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Humo , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisisRESUMEN
Non-optimal temperatures are associated with premature deaths globally. However, the evidence is limited in low- and middle-income countries, and the productivity losses due to non-optimal temperatures have not been quantified. We aimed to estimate the work-related impacts and economic losses attributable to non-optimal temperatures in Brazil. We collected daily mortality data from 510 immediate regions in Brazil during 2000 and 2019. A two-stage time-series analysis was applied to evaluate the association between non-optimum temperatures and the Productivity-Adjusted Life-Years (PALYs) lost. The temperature-PALYs association was fitted for each location in the first stage and then we applied meta-analyses to obtain the national estimations. The attributable fraction (AF) of PALY lost due to ambient temperatures and the corresponding economic costs were calculated for different subgroups of the working-age population. A total of 3,629,661 of PALYs lost were attributed to non-optimal temperatures during 2000-2019 in Brazil, corresponding to 2.90 % (95 % CI: 1.82 %, 3.95 %) of the total PALYs lost. Non-optimal temperatures have led to US$104.86 billion (95 % CI: 65.95, 142.70) of economic costs related to PALYs lost and the economic burden was more substantial in males and the population aged 15-44 years. Higher risks of extreme cold temperatures were observed in the South region in Brazil while extreme hot temperatures were observed in the Central West and Northeast regions. In conclusion, non-optimal temperatures are associated with considerable labour losses as well as economic costs in Brazil. Tailored policies and adaptation strategies should be proposed to mitigate the impacts of non-optimal temperatures on the labour supply in a changing climate.
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Eficiencia , Mortalidad Prematura , Masculino , Humanos , Temperatura , Años de Vida Ajustados por Calidad de Vida , Brasil/epidemiologíaRESUMEN
Accurate estimates of the causal effect of air pollution on health outcomes, are critical when calculating attributable disease burdens. Brazil has a large population exposed to fast-growing emissions of air pollutants, however no national level studies have been conducted to examine the causal effect of PM2.5 exposure on health outcomes. This study proposes a novel approach, to accurately estimate the causal relationship between daily PM2.5 exposure and hospitalisations, across 1,814 Brazilian cities during 2000-2015. A variant of the difference-in-differences (DID) approach was applied under a counterfactual framework. Daily time series data were divided into panels. Seasonality and long-term trend were controlled using indicators for the panel. Variables which do not change within a short-period were controlled using a dummy variable for the day. Controls for variables which vary day by day, were included in the model. We found the proposed model exhibited competitive power performance in detecting causal associations between short-term PM2.5 exposure and hospitalisations in Brazil. A 10 µg/m3 increase in PM2.5 concentrations over four days (lag 0-3) was associated with a 1.06 % (95 % CI: 0.94 to 1.17) increase in all-cause hospitalisations and accounted for 1.26 % (95 % CI: 1.12-1.39) of total hospitalisations. Larger effects were found for children aged 0-4 years and the elderly aged 80+ years, suggesting policies should be developed to minimise the exposure of these age groups.
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Contaminantes Atmosféricos , Contaminación del Aire , Anciano , Niño , Humanos , Brasil/epidemiología , Material Particulado/efectos adversos , Material Particulado/análisis , Factores de Tiempo , Exposición a Riesgos Ambientales/efectos adversos , Exposición a Riesgos Ambientales/análisis , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , HospitalizaciónRESUMEN
Background: Climate change is increasing the risks of injuries, diseases, and deaths globally. However, the association between ambient temperature and renal diseases has not been fully characterized. This study aimed to quantify the risk and attributable burden for hospitalizations of renal diseases related to ambient temperature. Methods: Daily hospital admission data from 1816 cities in Brazil were collected during 2000 and 2015. A time-stratified case-crossover design was applied to evaluate the association between temperature and renal diseases. Relative risks (RRs), attributable fractions (AFs), and their confidence intervals (CIs) were calculated to estimate the associations and attributable burden. Findings: A total of 2,726,886 hospitalizations for renal diseases were recorded during the study period. For every 1°C increase in daily mean temperature, the estimated risk of hospitalization for renal diseases over lag 0-7 days increased by 0·9% (RR = 1·009, 95% CI: 1·008-1·010) at the national level. The associations between temperature and renal diseases were largest at lag 0 days but remained for lag 1-2 days. The risk was more prominent in females, children aged 0-4 years, and the elderly ≥ 80 years. 7·4% (95% CI: 5·2-9·6%) of hospitalizations for renal diseases could be attributable to the increase of temperature, equating to 202,093 (95% CI: 141,554-260,594) cases. Interpretation: This nationwide study provides robust evidence that more policies should be developed to prevent heat-related hospitalizations and mitigate climate change. Funding: China Scholarship Council, and the Australian National Health and Medical Research Council.
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BACKGROUND: Both cold and hot temperature have been associated with the onset of asthma, but it remains largely unknown about the risk of asthma hospitalisation associated with short-term temperature fluctuation or temperature variability (TV). OBJECTIVE: To explore the association between short-term exposure to TV and asthma hospitalisation in Brazil. METHODS: Data for asthma hospitalisation and weather conditions were collected from 1816 Brazilian cities between 2000 and 2015. TV was calculated as the SD of all daily minimum and maximum temperatures within 0-7 days prior to current day. A time-stratified case-crossover design was performed to quantify the association between TV and hospitalisation for asthma. RESULTS: A total of 2 818 911 hospitalisations for asthma were identified during the study period. Each 1°C increase in 0-7 days' TV exposure was related to a 1.0% (95% CI 0.7% to 1.4%) increase in asthma hospitalisations. The elderly were more vulnerable to TV than other age groups, while region and season appeared to significantly modify the associations. There were 159 305 (95% CI 55 293 to 2 58 054) hospitalisations, US$48.41 million (95% CI US$16.92 to US$78.30 million) inpatient costs at 2015 price and 450.44 thousand inpatient days (95% CI 156.08 to 729.91 thousand days) associated with TV during the study period. The fraction of asthma hospitalisations attributable to TV increased from 5.32% in 2000 to 5.88% in 2015. CONCLUSION: TV was significantly associated with asthma hospitalisation and the corresponding substantial health costs in Brazil. Our findings suggest that preventive measures of asthma should take TV into account.
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Asma , Exposición a Riesgos Ambientales , Anciano , Asma/epidemiología , Brasil/epidemiología , Estudios Cruzados , Exposición a Riesgos Ambientales/análisis , Hospitalización , Humanos , Estaciones del Año , TemperaturaRESUMEN
Abstract Objective: Melatonin has a protective role in adults with cardiovascular disease, but the effects of melatonin in children with cardiac dysfunction are not well understood. This study was designed to explore the variations in melatonin, myeloperoxidase, and caspase-3 levels in children suffering from heart failure. Methods: Seventy-two pediatric patients with heart failure and twelve healthy children were enrolled in this study. A modified Ross scoring system was used to evaluate clinical cardiac function. Patients with a score of >2 points were included in the study and were divided into three groups according to severity of heart failure: mild (score: 3-6), moderate (score: 7-9), and severe (score: 10-12). Echocardiographic parameters, laboratory data, and serum levels of melatonin, myeloperoxidase, and caspase-3 were measured and analyzed in all patients. Results: Compared with patients with mild and moderate heart failure, patients in the severe heart failure group had significantly decreased left ventricular ejection fraction (p < 0.001), and significantly increased serum melatonin levels (p = 0.013) and myeloperoxidase levels (p < 0.001). Serum melatonin levels were positively correlated with serum caspase-3 levels (p < 0.001). The optimal cutoff values of serum melatonin levels for the diagnosis of severe heart failure and primary cardiomyopathy in pediatric patients with heart failure were 54.14 pg/mL and 32.88 pg/mL, respectively. Conclusions: Serum melatonin and myeloperoxidase levels were increased in children with severe heart failure. It is likely that increasing melatonin levels may act as a compensatory mechanism in pediatric children with heart failure.
Resumo Objetivo: A melatonina possui um papel protetor em adultos com doença cardiovascular, porém os efeitos da melatonina em crianças com disfunção cardíaca não são bem entendidos. O estudo foi projetado para explorar a variação nos níveis de melatonina, mieloperoxidase e caspase 3 em crianças que sofrem de insuficiência cardíaca. Métodos: 72 pacientes pediátricos com insuficiência cardíaca e 12 crianças saudáveis foram inscritos no estudo. Um sistema de classificação de Ross modificada foi utilizado para avaliar a função cardíaca clínica. Os pacientes com escore de > 2 pontos foram incluídas no estudo e foram divididos em três grupos de acordo com a gravidade da insuficiência cardíaca: leve (escore: 3-6), moderada (escore: 7-9) e grave (escore: 10-12). Os parâmetros ecocardiográficos, dados laboratoriais e níveis séricos de melatonina, mieloperoxidase e caspase 3 foram medidos e analisados em todos os pacientes. Resultados: Em comparação com os pacientes com insuficiência cardíaca de gravidade leve e moderada, os pacientes no grupo de insuficiência cardíaca grave apresentaram redução significativa da fração de ejeção do ventrículo esquerdo (p < 0,001) e aumento significativo nos níveis séricos de melatonina (p = 0,013) e níveis de mieloperoxidase (p < 0,001). Os níveis séricos de melatonina foram positivamente correlacionados com os níveis séricos de caspase 3 (p < 0,001). Os valores de corte ideais dos níveis séricos de melatonina para diagnóstico de IC e cardiomiopatia primária em pacientes pediátricos com insuficiência cardíaca foram 54,14 pg/mL e 32,88 pg/mL, respectivamente. Conclusões: Os níveis séricos de melatonina e mieloperoxidase mostraram aumento em crianças com insuficiência cardíaca grave. Especulamos se o aumento nos níveis de melatonina pode agir como um mecanismo compensatório em crianças pediátricas com insuficiência cardíaca.
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Humanos , Masculino , Femenino , Lactante , Preescolar , Niño , Caspasa 3/sangre , Insuficiencia Cardíaca/sangre , Melatonina/sangre , Índice de Severidad de la Enfermedad , Ecocardiografía , Biomarcadores/sangre , Estudios de Casos y Controles , Peroxidasa/sangre , Insuficiencia Cardíaca/etiologíaRESUMEN
OBJECTIVE: Melatonin has a protective role in adults with cardiovascular disease, but the effects of melatonin in children with cardiac dysfunction are not well understood. This study was designed to explore the variations in melatonin, myeloperoxidase, and caspase-3 levels in children suffering from heart failure. METHODS: Seventy-two pediatric patients with heart failure and twelve healthy children were enrolled in this study. A modified Ross scoring system was used to evaluate clinical cardiac function. Patients with a score of >2 points were included in the study and were divided into three groups according to severity of heart failure: mild (score: 3-6), moderate (score: 7-9), and severe (score: 10-12). Echocardiographic parameters, laboratory data, and serum levels of melatonin, myeloperoxidase, and caspase-3 were measured and analyzed in all patients. RESULTS: Compared with patients with mild and moderate heart failure, patients in the severe heart failure group had significantly decreased left ventricular ejection fraction (p<0.001), and significantly increased serum melatonin levels (p=0.013) and myeloperoxidase levels (p<0.001). Serum melatonin levels were positively correlated with serum caspase-3 levels (p<0.001). The optimal cutoff values of serum melatonin levels for the diagnosis of severe heart failure and primary cardiomyopathy in pediatric patients with heart failure were 54.14pg/mL and 32.88pg/mL, respectively. CONCLUSIONS: Serum melatonin and myeloperoxidase levels were increased in children with severe heart failure. It is likely that increasing melatonin levels may act as a compensatory mechanism in pediatric children with heart failure.
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Caspasa 3/sangre , Insuficiencia Cardíaca/sangre , Melatonina/sangre , Peroxidasa/sangre , Biomarcadores/sangre , Estudios de Casos y Controles , Niño , Preescolar , Ecocardiografía , Femenino , Insuficiencia Cardíaca/etiología , Humanos , Lactante , Masculino , Índice de Severidad de la EnfermedadRESUMEN
INTRODUCTION: Hypermethylation of relevant genes may affect the prognosis of patients with cancer. The purpose of this study was to analyze whether methylation of the promoter regions of cell cycle regulators as well as elevated α-Fetoprotein (AFP) levels are useful prognostic factors for patients with hepatocellular carcinoma (HCC). MATERIAL AND METHODS: Nested methylation-specific PCR (nested-MSP) was used to analyze methylation status of the promoter regions of p15, p16, p21, p27, and ras-association domain family 1 (RASSF1A) genes in tumor specimens from 50 patients with HCC. RESULTS: Promoter methylation was most common in the RASSF1A gene (96%), followed by the p16 gene (56%), the p21 gene (44%), the p15 gene (28%), and the p27 gene (2%). Patients with a serum AFP level < 400 ng/mL and an unmethylated p21 promoter had a better prognosis than patients with a serum AFP level ≥ 400 ng/mL and a methylated p21 promoter (overall survival, p = 0.076; disease-free survival, p = 0.016). In addition, patients with full methylation of the promoter region of RASSF1A had a better prognosis than patients with a partially methylated or unmethylated RASSF1A promoter region if their serum AFP level was ≥ 400 ng/mL (overall survival, p = 0.028; disease-free survival, p = 0.078). CONCLUSION: A partially methylated or unmethylated RASSF1A promoter as well as elevated serum AFP level or methylation of p21 in addition to elevated serum AFP level might be associated with poor prognosis in patients with hepatocellular carcinoma.
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Biomarcadores de Tumor/sangre , Biomarcadores de Tumor/genética , Carcinoma Hepatocelular/diagnóstico , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Metilación de ADN , Neoplasias Hepáticas/diagnóstico , Proteínas Supresoras de Tumor/genética , alfa-Fetoproteínas/análisis , Anciano , Carcinoma Hepatocelular/sangre , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/terapia , Supervivencia sin Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Estimación de Kaplan-Meier , Neoplasias Hepáticas/sangre , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/terapia , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Valor Predictivo de las Pruebas , Regiones Promotoras Genéticas , Factores de Riesgo , Factores de TiempoRESUMEN
Background The sea cucumber lysozyme belongs to the family of invertebrate lysozymes and is thought to be a key defense factor in protecting aquaculture animals against bacterial infection. Recently, evidence was found that the sea cucumber lysozyme exerts broad spectrum antimicrobial action in vitro against Gram-negative and Gram-positive bacteria, and it also has more potent antimicrobial activity independent of its enzymatic activity. To explore the antimicrobial role of this non-enzymatic lysozyme and model its structure to novel antimicrobial peptides, the peptide from the C-terminal amino acid residues 70-146 of the sea cucumber lysozyme in Stichopus japonicus (SjLys-C) was heterologously expressed in Escherichia coli Rosetta(DE3)pLysS. Results The fusion protein system led to over-expression of the soluble and highly stable product, an approximate 26 kDa recombinant SjLys-C protein (rSjLys-C). The present study showed that rSjLys-C displayed strong antimicrobial activity against the tested Gram-positive and Gram-negative bacteria. In particular, the heat-treated rSjLys-C exhibited more inhibitive activity than the native rSjLys-C. The structural analysis of SjLys-C showed that it is a typical hydrophilic peptide and contains a helix-loop-helix motif. The modeling of SjLys-C molecular structures at different temperatures revealed that the tertiary structure of SjLys-C at 100°C underwent a conformational change which is favorable for enhancing antimicrobial activity. Conclusion These results indicate that the expressed rSjLys-C is a highly soluble product and has a strong antimicrobial activity. Therefore, gaining a large quantity of biologically active rSjLys-C will be used for further biochemical and structural studies and provide a potential use in aquaculture and medicine.
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Animales , Fragmentos de Péptidos/metabolismo , Pepinos de Mar , Proteínas Recombinantes , Antiinfecciosos/farmacología , Solubilidad , Temperatura , Bacterias/efectos de los fármacos , Técnicas In Vitro , Muramidasa , Western Blotting , Stichopus , Escherichia coliRESUMEN
Genomic simple sequence repeat (SSR) markers are particularly valuable in studies of genetic diversity, evolution, genetic linkage map construction, quantitative trait loci tagging, and marker-assisted selection because of their multi-allelic nature, reproducibility, co-dominant inheritance, high abundance, and extensive genome coverage. The traditional methods of SSR marker development, such as genomic-SSR hybrid screening and microsatellite enrichment, have the disadvantages of high cost and complex operation. The selectively amplified microsatellite method is less costly and highly efficient as well as being simple and convenient. In this study, 252 sequences with SSRs were cloned from the rubber tree (Hevea brasiliensis) genome from which 258 SSR loci were obtained. The average repeat number was six. There were only 10 (3.9%) mononucleotide, trinucleotide, and pentanucleotide repeats, whereas the remaining 248 (96.1%) were dinucleotide repeats, including 128 (49.6%) GT/CA repeats, 118 (45.7%) GA/CT repeats, and 2 (0.8%) AT/TA repeats. A total of 126 primer pairs (see ESM) were successfully designed of which 36 primer pairs generated polymorphic products from 12 accessions of the cultivated species, 4 related species, and 3 species of the family Euphorbiaceae. In addition, investigations based on four genomic SSRs (GAR4, ACR22, CTR25, and GTR28) by cloning and sequencing provided evidence for cross-species/genera applicability, and homologous sequences were obtained from the rubber tree and Euphorbiaceae. Further analysis about the variation of the flanking regions of the four markers was carried out.
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Genoma de Planta , Hevea/genética , Repeticiones de Microsatélite , Secuencia de Bases , Clonación Molecular , ADN de Plantas/genética , Repeticiones de Dinucleótido , Marcadores Genéticos , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
Out of 260 polymorphic loci screened from a total of 441 pairs of EST-SSR and genomic-SSR primers, 176 were used for constructing the genetic map of rubber tree (Hevea brasiliensis) by an F1 segregating population including 94 progenies from the cross Reyan 88-13xIAN873. Chi-square test carried out on the polymorphic loci used in constructing the map showed that 147 loci followed a segregation ratio of 1:1 and 12 loci followed a ratio of 1:2:1 and 17 loci followed a ratio of 1:1:1:1. Only 13 (7.38%) loci were distorted from the Mendelian ratio. The genetic linkage map consisted of 91 marker loci in 18 linkage groups and covered 1 937.06 cM with an average genetic distance of 21.29 cM between adjacent markers. The largest linkage group consisted of 16 marker loci, while the smallest one contained only 2 marker loci.