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1.
Ecotoxicol Environ Saf ; 208: 111695, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396026

RESUMO

The priority list of freshwater pollutants is increasingly amended by pharmaceuticals. Their impact on the aquatic biota can be modulated by the presence of typical pollutants, like pesticides, and/or abnormal heating. The aim of this study was to elucidate potentially hazardous impact of combined environmental factors on the freshwater mussels by analyzing various sets of biochemical markers. We treated the bivalve molluscs of Unio tumidus with non-steroidal anti-inflammatory drug diclofenac (Dc, 2 nM), calcium antagonist and antihypertensive drug nifedipine (Nf, 2 nM) or organophosphonate glyphosate-based herbicide Roundup MAX (Rn, 79 nM of glyphosate) at 18 °C as well as with the mixture of these substances at 18 °C (Mix) or 25 °C (MixT) during 14 days. The concentrations used were correspondent to the environmentally relevant levels. The biomarkers of stress and toxicity were evaluated in digestive gland, except the lysosomal membrane stability measured in hemocytes. Exposures caused an oxidative stress due to the decreased SOD and GST activities and GSH/GSSG ratio, increased levels of thiobarbituric acid-reactive substances and protein carbonyls (with some exceptions). Dc increased cathepsin D activity in lysosomes. Nf increased lysosomal membrane stability and caspase-3 activity. Rn caused a dramatic distortion of metallo-thiolome due to increased levels of GSH and metallothionein-related thiols (MTSH) as well as depletion of Zn, Cu and Cd in the composition of metallothioneins, and decreased Zn/Cu molar ratio in the tissue. The particular toxicity of Rn was also attested by decreased lysosomal membrane stability and cholinesterase activity. Canonical discriminant analysis separated Rn-, Mix- and MixT-groups from the joint set of C-, Dc- and Nf-groups. Generally, compound-specific effects were expressed in U. tumidus responses to the mixtures, but in MixT-group some effects were particular or extremely strong. Multi-marker approach and integrative analysis proved to be a useful tool for understanding possible future risks to freshwater mussels under a combination of xenobiotics and warming climate.


Assuntos
Exposição Ambiental/efeitos adversos , Herbicidas/toxicidade , Preparações Farmacêuticas , Unio/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Exposição Ambiental/análise , Herbicidas/metabolismo , Temperatura Alta/efeitos adversos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Preparações Farmacêuticas/metabolismo , Unio/metabolismo , Poluentes Químicos da Água/metabolismo
2.
Nat Commun ; 12(1): 713, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514738

RESUMO

Despite proteotoxic stress and heat shock being implicated in diverse pathologies, currently no methodology to inflict defined, subcellular thermal damage exists. Here, we present such a single-cell method compatible with laser-scanning microscopes, adopting the plasmon resonance principle. Dose-defined heat causes protein damage in subcellular compartments, rapid heat-shock chaperone recruitment, and ensuing engagement of the ubiquitin-proteasome system, providing unprecedented insights into the spatiotemporal response to thermal damage relevant for degenerative diseases, with broad applicability in biomedicine. Using this versatile method, we discover that HSP70 chaperone and its interactors are recruited to sites of thermally damaged proteins within seconds, and we report here mechanistically important determinants of such HSP70 recruitment. Finally, we demonstrate a so-far unsuspected involvement of p97(VCP) translocase in the processing of heat-damaged proteins. Overall, we report an approach to inflict targeted thermal protein damage and its application to elucidate cellular stress-response pathways that are emerging as promising therapeutic targets.


Assuntos
Proteínas de Choque Térmico HSP70/metabolismo , Resposta ao Choque Térmico , Análise de Célula Única/métodos , Proteína com Valosina/metabolismo , Linhagem Celular Tumoral , Temperatura Alta/efeitos adversos , Humanos , Nanopartículas Metálicas/química , Complexo de Endopeptidases do Proteassoma/metabolismo , Prata/química , Ressonância de Plasmônio de Superfície , Ubiquitina/metabolismo , Proteína com Valosina/genética
3.
BMJ Case Rep ; 13(12)2020 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-33370969

RESUMO

A 91-year-old Caucasian man on warfarin for atrial fibrillation presented in view of sudden-onset haemoptysis with fresh bleeding with clots immediately after having eaten a piping-hot traditional cheesecake (pastizz) and burning the soft-palate of his mouth. The haemoptysis had resolved by the time that the patient had arrived to hospital. On examination, a 2 cm by 2 cm dark red, solitary mass could be seen just anterior to the uvula. This was not causing any pain or discomfort to the patient. Blood results were mostly unremarkable except for a raised international normalised ratio (INR) of 3.53. The patient was administered 5 mg vitamin K orally in attempt to lower the INR level and warfarin was subsequently omitted for 7 days. He was also prescribed oral steroids on discharge. The lesion resolved in 7 days and warfarin was restarted then with no further consequences.


Assuntos
Anticoagulantes/efeitos adversos , Fibrilação Atrial/tratamento farmacológico , Queimaduras/diagnóstico , Hematoma/diagnóstico , Hemoptise/etiologia , Varfarina/efeitos adversos , Idoso de 80 Anos ou mais , Coagulação Sanguínea/efeitos dos fármacos , Queimaduras/etiologia , Alimentos/efeitos adversos , Hematoma/tratamento farmacológico , Hematoma/etiologia , Hemoptise/tratamento farmacológico , Temperatura Alta/efeitos adversos , Humanos , Coeficiente Internacional Normatizado , Masculino , Palato Mole/irrigação sanguínea , Palato Mole/lesões , Úvula/irrigação sanguínea , Úvula/lesões , Vitamina K/administração & dosagem
4.
Environ Health Prev Med ; 25(1): 63, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33115400

RESUMO

BACKGROUND: Need to a simple, available, accurate, comprehensive, and valid indicator is felt to assess thermal effects. Therefore, the present study was aimed to develop and validate the environmental heat strain risk assessment (EHSRA) index using structural equation modeling (SEM) based on empirical relations. METHODS: This cross-sectional study was performed on 201 male workers in environments with various climatic conditions. The heart rate and tympanic temperature of the individuals were monitored at times of 30, 60, and 90 min after beginning the work. At these times, values of dry temperature, wet temperature, globe temperature, and air velocity were also measured and metabolism rate and clothing thermal insulation value were estimated. At the end, a theoretical model was depicted in AMOS software and obtained coefficients were applied to develop a novel index. The scores of this indicator were categorized into four risk levels via ROC curves and validate using linear regression analysis. RESULTS: Indirect effect coefficients of the globe temperature, dry temperature, wet temperature, air velocity, metabolism, and clothing thermal insulation variables on the tympanic temperature were computed by 0.77, 0.75, 0.69, 0.24, 0.49, and 0.39, respectively. These coefficients were applied to develop the index. Optimal cut-off points of boundaries between risk levels included 12.02, 15.88, and 17.56. The results showed that the EHSRA index justified 75% of the variations of the tympanic temperature (R2 = 0.75). CONCLUSIONS: The novel index possesses appropriate validity. It was suggested that this indicator is applied and validated in various environments in the next studies.


Assuntos
Saúde Ambiental/métodos , Resposta ao Choque Térmico , Temperatura Alta/efeitos adversos , Adulto , Humanos , Irã (Geográfico) , Análise de Classes Latentes , Masculino , Pessoa de Meia-Idade , Medição de Risco/métodos , Adulto Jovem
5.
Eur Rev Med Pharmacol Sci ; 24(18): 9753-9759, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33015822

RESUMO

OBJECTIVE: The weather-related conditions change the ecosystem and pose a threat to social, economic and environmental development. It creates unprecedented or unanticipated human health problems in various places or times of the year. Africa is the world's second largest and most populous continent and has relatively changeable weather conditions. The present study aims to investigate the impact of weather conditions, heat and humidity on the incidence and mortality of COVID-19 pandemic in various regions of Africa. MATERIALS AND METHODS: In this study, 16 highly populated countries from North, South, East, West, and Central African regions were selected. The data on COVID-19 pandemic including daily new cases and new deaths were recorded from World Health Organization. The daily temperature and humidity figures were obtained from the weather web "Time and Date". The daily cases, deaths, temperature and humidity were recorded from the date of appearance of first case of "Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)" in the African region, from Feb 14 to August 2, 2020. RESULTS: In African countries, the daily basis mean temperature from Feb 14, 2020 to August 2, 2020 was 26.16±0.12°C, and humidity was 57.41±0.38%. The overall results revealed a significant inverse correlation between humidity and the number of cases (r= -0.192, p<0.001) and deaths (r= -0.213, p<0.001). Similarly, a significant inverse correlation was found between temperature and the number of cases (r= -0.25, p<0.001) and deaths (r=-0.18, p<0.001). Furthermore, the regression results showed that with 1% increase in humidity the number of cases and deaths was significantly reduced by 3.6% and 3.7% respectively. Congruently, with 1°C increase in temperature, the number of cases and deaths was also significantly reduced by 15.1% and 10.5%, respectively. CONCLUSIONS: Increase in relative humidity and temperature was associated with a decrease in the number of daily cases and deaths due to COVID-19 pandemic in various African countries. The study findings on weather events and COVID-19 pandemic have an impact at African regional levels to project the incidence and mortality trends with regional weather events which will enhance public health readiness and assist in planning to fight against this pandemic.


Assuntos
Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/mortalidade , Temperatura Alta/efeitos adversos , Umidade/efeitos adversos , Pandemias/estatística & dados numéricos , Pneumonia Viral/epidemiologia , Pneumonia Viral/mortalidade , Tempo (Meteorologia) , África/epidemiologia , Betacoronavirus , Humanos , Incidência
6.
Tex Med ; 116(9): 4-5, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33023283

RESUMO

Human health is inextricably connected with the health of the environment. Our actions to reduce the threats of climate change and global warming are key to our well-being and survival.


Assuntos
Mudança Climática , Exposição Ambiental/efeitos adversos , Aquecimento Global/prevenção & controle , Saúde , Temperatura Alta/efeitos adversos , Papel do Médico , Responsabilidade Social , Promoção da Saúde , Humanos , Texas
7.
Tex Med ; 116(9): 4, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33023284

RESUMO

While the World Health Organization estimates that climate change will cause approximately 250,000 additional deaths per year worldwide from malnutrition, malaria, diarrhea, and heat stress, these estimates are based on assumptions using models that have not been validated using real world, observational data.


Assuntos
Mudança Climática , Exposição Ambiental/efeitos adversos , Aquecimento Global , Educação em Saúde , Saúde , Causas de Morte , Diarreia , Resposta ao Choque Térmico , Temperatura Alta/efeitos adversos , Humanos , Malária , Desnutrição , Texas
9.
Nat Commun ; 11(1): 4897, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994415

RESUMO

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. However, its feedbacks to climate warming and underlying microbial mechanisms are still poorly understood. Here we show that the temperature sensitivity of soil microbial respiration (Q10) in a temperate grassland ecosystem persistently decreases by 12.0 ± 3.7% across 7 years of warming. Also, the shifts of microbial communities play critical roles in regulating thermal adaptation of soil respiration. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improves the modeling performance of soil microbial respiration by 5-19%, and reduces model parametric uncertainty by 55-71%. In addition, modeling analyses show that the microbial thermal adaptation can lead to considerably less heterotrophic respiration (11.6 ± 7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.


Assuntos
Carbono/análise , Metagenoma/genética , Microbiota/fisiologia , Microbiologia do Solo , Solo/química , Aclimatação/genética , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Celulose/metabolismo , DNA Ambiental/genética , DNA Ambiental/isolamento & purificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Aquecimento Global , Pradaria , Temperatura Alta/efeitos adversos , Metagenômica , Modelos Genéticos , Raízes de Plantas/química , Poaceae/química
10.
Nat Genet ; 52(10): 1099-1110, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32989325

RESUMO

Cattle pastoralism plays a central role in human livelihood in Africa. However, the genetic history of its success remains unknown. Here, through whole-genome sequence analysis of 172 indigenous African cattle from 16 breeds representative of the main cattle groups, we identify a major taurine × indicine cattle admixture event dated to circa 750-1,050 yr ago, which has shaped the genome of today's cattle in the Horn of Africa. We identify 16 loci linked to African environmental adaptations across crossbred animals showing an excess of taurine or indicine ancestry. These include immune-, heat-tolerance- and reproduction-related genes. Moreover, we identify one highly divergent locus in African taurine cattle, which is putatively linked to trypanotolerance and present in crossbred cattle living in trypanosomosis-infested areas. Our findings indicate that a combination of past taurine and recent indicine admixture-derived genetic resources is at the root of the present success of African pastoralism.


Assuntos
Adaptação Fisiológica/genética , Cruzamento , Genoma/genética , Sequenciamento Completo do Genoma , África , Alelos , Animais , Bovinos , Genótipo , Temperatura Alta/efeitos adversos , Humanos , Mosaicismo , Polimorfismo de Nucleotídeo Único/genética , Reprodução/genética , Taurina/genética
11.
Environ Health ; 19(1): 98, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32933549

RESUMO

BACKGROUND: Several studies have investigated the associations between ambient temperature and years of life lost (YLLs), but few focused on the difference of life loss attributable to temperature among different socioeconomic development levels. OBJECTIVES: We investigated the disparity in temperature-YLL rate relationships and life loss per death attributable to nonoptimal temperature in regions with various development levels. METHODS: Three hundred sixty-four Chinese counties or districts were classified into 92 high-development regions (HDRs) and 272 low-development regions (LDRs) according to socioeconomic factors of each location using K-means clustering approach. We used distributed lag non-linear models (DLNM) and multivariate meta-analysis to estimate the temperature-YLL rate relationships. We calculated attributable fraction (AF) of YLL and temperature-related average life loss per death to compare mortality burden of temperature between HDRs and LDRs. Stratified analyses were conducted by region, age, sex and cause of death. RESULTS: We found that non-optimal temperatures increased YLL rates in both HDRs and LDRs, but all subgroups in LDRs were more vulnerable. The disparity of cold effects between HDRs and LDRs was significant, while the difference in heat effect was insignificant. The overall AF of non-optimal temperature in LDRs [AF = 12.2, 95% empirical confidence interval (eCI):11.0-13.5%] was higher than that in HDRs (AF = 8.9, 95% eCI: 8.3-9.5%). Subgroups analyses found that most groups in LDRs had greater AFs than that in HDRs. The average life loss per death due to non-optimal temperature in LDRs (1.91 years, 95% eCI: 1.72-2.10) was also higher than that in HDRs (1.32 years, 95% eCI: 1.23-1.41). Most of AFs and life loss per death were caused by moderate cold in both HDRs and LDRs. CONCLUSIONS: Mortality burden caused by temperature was more significant in LDRs than that in HDRs, which means that more attention should be paid to vulnerable populations in LDRs in planning adaptive strategies.


Assuntos
Temperatura Baixa/efeitos adversos , Temperatura Alta/efeitos adversos , Expectativa de Vida , China , Geografia , Humanos , Modelos Lineares , Análise Multivariada
14.
BMC Infect Dis ; 20(1): 462, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32611396

RESUMO

BACKGROUND: At present, there are few studies on polymorphism of Mycobacterium tuberculosis (Mtb) gene and how it affects the TB epidemic. This study aimed to document the differences of polymorphisms between tuberculosis hot and cold spot areas of Guangxi Zhuang Autonomous Region, China. METHODS: The cold and hot spot areas, each with 3 counties, had been pre-identified by TB incidence for 5 years from the surveillance database. Whole genome sequencing analysis was performed on all sputum Mtb isolates from the detected cases during January and June 2018. Single nucleotide polymorphism (SNP) of each isolate compared to the H37Rv strain were called and used for lineage and sub-lineage identification. Pairwise SNP differences between every pair of isolates were computed. Analyses of Molecular Variance (AMOVA) across counties of the same hot or cold spot area and between the two areas were performed. RESULTS: As a whole, 59.8% (57.7% sub-lineage 2.2 and 2.1% sub-lineage 2.1) and 39.8% (17.8% sub-lineage 4.4, 6.5% sub-lineage 4.2 and 15.5% sub-lineage 4.5) of the Mtb strains were Lineage 2 and Lineage 4 respectively. The percentages of sub-lineage 2.2 (Beijing family strains) are significantly higher in hot spots. Through the MDS dimension reduction, the genomic population structure in the three hot spot counties is significantly different from those three cold spot counties (T-test p = 0.05). The median of SNPs distances among Mtb isolates in cold spots was greater than that in hot spots (897 vs 746, Rank-sum test p < 0.001). Three genomic clusters, each with genomic distance ≤12 SNPs, were identified with 2, 3 and 4 consanguineous strains. Two clusters were from hot spots and one was from cold spots. CONCLUSION: Narrower genotype diversity in the hot area may indicate higher transmissibility of the Mtb strains in the area compared to those in the cold spot area.


Assuntos
Temperatura Baixa , Epidemias , Temperatura Alta/efeitos adversos , Mycobacterium tuberculosis/genética , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/epidemiologia , China/epidemiologia , Análise por Conglomerados , Genótipo , Humanos , Incidência , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Polimorfismo de Nucleotídeo Único , Escarro/microbiologia , Tuberculose Pulmonar/transmissão , Sequenciamento Completo do Genoma
15.
Dermatol Online J ; 26(4)2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32621693

RESUMO

Erythema ab igne is a skin condition mainly caused by heat exposure. Erythema ab igne usually follows a favorable prognosis. However, it may increase the risk of developing cutaneous malignancy in the involved skin. Being familiar with the type of cutaneous malignancies that may arise in the site of erythema ab igne is considerably important. To our knowledge, this letter presents the first case that shows the association between erythema ab igne and basal cell carcinoma.


Assuntos
Carcinoma Basocelular/etiologia , Eritema/complicações , Neoplasias Cutâneas/etiologia , Pele/patologia , Biópsia , Carcinoma Basocelular/patologia , Diagnóstico Diferencial , Temperatura Alta/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Cutâneas/patologia
16.
PLoS One ; 15(6): e0234994, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32598370

RESUMO

Estuaries are characterized by high fluctuation of their environmental conditions. Environmental parameters measured show that the seawater properties of the Quempillén estuary (i.e. temperature, salinity, pCO2, pH and ΩCaCO3) were highly fluctuating and related with season and tide. We test the effects of increasing temperature and pCO2 in the seawater on the physiological energetics of the bivalve Ostrea chilensis. Juvenile oysters were exposed to an orthogonal combination of three temperatures (10, 15, and 20°C) and two pCO2 levels (~400 and ~1000 µatm) for a period of 60 days to evaluate the temporal effect (i.e. 10, 20, 30, 60 days) on the physiological rates of the oysters. Results indicated a significant effect of temperature and time of exposure on the clearance rate, while pCO2 and the interaction between pCO2 and the other factors studied did not show significant effects. Significant effects of temperature and time of exposure were also observed on the absorption rate, but not the pCO2 nor its interaction with other factors studied. Oxygen consumption was significantly affected by pCO2, temperature and time. Scope for growth was only significantly affected by time; despite this, the highest values were observed for individuals subject to to 20°C and to ~1000 µatm pCO2. In this study, Ostrea chilensis showed high phenotypic plasticity to respond to the high levels of temperature and pCO2 experienced in its habitat as no negative physiological effects were observed. Thus, the highly variable conditions of this organism's environment could select for individuals that are more resistant to future scenarios of climate change, mainly to warming and acidification.


Assuntos
Aclimatação , Variação Biológica da População , Exposição Ambiental/efeitos adversos , Ostrea/fisiologia , Água do Mar/química , Animais , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Chile , Mudança Climática , Temperatura Alta/efeitos adversos , Concentração de Íons de Hidrogênio , Consumo de Oxigênio , Salinidade
17.
MMWR Morb Mortal Wkly Rep ; 69(24): 729-734, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32555133

RESUMO

Deaths attributable to natural heat exposure, although generally considered preventable (1), represent a continuing public health concern in the United States. During 2004-2018, an average of 702 heat-related deaths occurred in the United States annually. To study patterns in heat-related deaths by age group, sex, race/ethnicity, and level of urbanization, and to explore comorbid conditions associated with deaths resulting from heat exposure, CDC analyzed nationally comprehensive mortality data from the National Vital Statistics System (NVSS).* The rate of heat-related mortality tended to be higher among males, persons aged ≥65 years, non-Hispanic American Indian/Alaska Natives, and persons living in noncore nonmetropolitan and large central metropolitan counties. Natural heat exposure was a contributing cause of deaths attributed to certain chronic medical conditions and other external causes. Preparedness and response initiatives directed toward extreme heat events, currently underway at local, state, and national levels, can contribute to reducing morbidity and mortality associated with natural heat exposure. Successful public health interventions† to mitigate heat-related deaths include conducting outreach to vulnerable communities to increase awareness of heat-related symptoms and provide guidance for staying cool and hydrated, particularly for susceptible groups at risk such as young athletes and persons who are older or socially isolated (2). Improved coordination across various health care sectors could inform local activities to protect health during periods of high heat. For instance, jurisdictions can monitor weather conditions and syndromic surveillance data to guide timing of risk communication and other measures (e.g., developing and implementing heat response plans, facilitating communication and education activities) to prevent heat-related mortality in the United States. CDC also recommends that federal, state, local, and tribal jurisdictions open cooling centers or provide access to public locations with air conditioning for persons in need of a safe, cool, environment during hot weather conditions. In light of the coronavirus disease 2019 (COVID-19) pandemic, CDC updated its guidance on the use of cooling centers to provide best practices (e.g., potential changes to staffing procedures, separate areas for persons with symptoms of COVID-19, and physical distancing) to reduce the risk for introducing and transmitting SARS COV-2, the virus that causes COVID-19, into cooling centers.§.


Assuntos
Causas de Morte/tendências , Temperatura Alta/efeitos adversos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Adulto Jovem
18.
Aquat Toxicol ; 224: 105517, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32485496

RESUMO

Temperature affects physiological processes in organisms and the toxicity of chemicals. The widespread industrial use of ZnO causes contamination in aquatic ecosystems. This study aimed to investigate the chronic toxicity of ZnO at different temperatures using Daphnia magna as a model organism. The chronic toxicity of five different concentrations of ZnO was assessed at 23 °C and 28 °C. The results showed that higher concentrations of ZnO inhibited growth, production of first clutch eggs and juvenile accumulation at both 23 °C and 28 °C. Growth rate, numbers of first clutch eggs and juvenile accumulation were lower at 28 °C than at 23 °C. We also observed the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) activity. At higher concentrations of ZnO, oxidative stress was induced leading to increase MDA level and decrease SOD activity at 28 °C. These findings indicated that high temperature and high concentration of ZnO inhibited the activity of enzymatic proteins. Nonetheless, among all treatments, the accumulation of zinc in D. magna was not significantly different. Our results suggested that both ZnO and higher temperature induced oxidative stress in D. magna. As a result, MDA concentration increased, SOD activity changed and the growth and reproduction of D. magna was adversely affected.


Assuntos
Daphnia/efeitos dos fármacos , Temperatura Alta , Traços de História de Vida , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Animais , Daphnia/crescimento & desenvolvimento , Daphnia/metabolismo , Ecossistema , Temperatura Alta/efeitos adversos , Malondialdeído/metabolismo , Reprodução/efeitos dos fármacos
19.
Sci Rep ; 10(1): 7812, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385322

RESUMO

Health and performance impairments provoked by thermal stress are societal challenges geographically spreading and intensifying with global warming. Yet, science may be underestimating the true impact, since no study has evaluated effects of sunlight exposure on human brain temperature and function. Accordingly, performance in cognitively dominated and combined motor-cognitive tasks and markers of rising brainstem temperature were evaluated during exposure to simulated sunlight (equal to ~1000 watt/m2). Acute exposure did not affect any performance measures, whereas prolonged exposure of the head and neck provoked an elevation of the core temperature by 1 °C and significant impairments of cognitively dominated and motor task performances. Importantly, impairments emerged at considerably lower hyperthermia levels compared to previous experiments and to the trials in the presents study without radiant heating of the head. These findings highlight the importance of including the effect of sunlight radiative heating of the head and neck in future scientific evaluations of environmental heat stress impacts and specific protection of the head to minimize detrimental effects.


Assuntos
Cognição/fisiologia , Exercício Físico/fisiologia , Transtornos de Estresse por Calor/fisiopatologia , Luz Solar/efeitos adversos , Adulto , Temperatura Corporal , Regulação da Temperatura Corporal/fisiologia , Regulação da Temperatura Corporal/efeitos da radiação , Cognição/efeitos da radiação , Febre/etiologia , Febre/fisiopatologia , Cabeça/fisiopatologia , Cabeça/efeitos da radiação , Transtornos de Estresse por Calor/etiologia , Resposta ao Choque Térmico/fisiologia , Resposta ao Choque Térmico/efeitos da radiação , Temperatura Alta/efeitos adversos , Humanos , Masculino , Energia Solar , Análise e Desempenho de Tarefas
20.
PLoS One ; 15(4): e0232451, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353050

RESUMO

Numerous neuronal properties including the synaptic vesicle release process, neurotransmitter receptor complement, and postsynaptic ion channels are involved in transforming synaptic inputs into postsynaptic spiking. Temperature is a significant influencer of neuronal function and synaptic integration. Changing temperature can affect neuronal physiology in a diversity of ways depending on how it affects different members of the cell's ion channel complement. Temperature's effects on neuronal function are critical for pathological states such as fever, which can trigger seizure activity, but are also important in interpreting and comparing results of experiments conducted at room vs physiological temperature. The goal of this study was to examine the influence of temperature on synaptic properties and ion channel function in thalamocortical (TC) relay neurons in acute brain slices of the dorsal lateral geniculate nucleus, a key synaptic target of retinal ganglion cells in the thalamus. Warming the superfusate in patch clamp experiments with acutely-prepared brain slices led to an overall inhibition of synaptically-driven spiking behavior in TC neurons in response to a retinal ganglion cell spike train. Further study revealed that this was associated with an increase in presynaptic synaptic vesicle release probability and synaptic depression and altered passive and active membrane properties. Additionally, warming the superfusate triggered activation of an inwardly rectifying potassium current and altered the voltage-dependence of voltage-gated Na+ currents and T-type calcium currents. This study highlights the importance of careful temperature control in ex vivo physiological experiments and illustrates how numerous properties such as synaptic inputs, active conductances, and passive membrane properties converge to determine spike output.


Assuntos
Corpos Geniculados/fisiologia , Temperatura Alta/efeitos adversos , Optogenética/métodos , Terminações Pré-Sinápticas/fisiologia , Células Ganglionares da Retina/fisiologia , Potenciais de Ação/fisiologia , Animais , Canais de Cálcio Tipo T/metabolismo , Feminino , Corpos Geniculados/citologia , Masculino , Camundongos , Técnicas de Patch-Clamp , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Transmissão Sináptica/fisiologia , Canais de Sódio Disparados por Voltagem/metabolismo
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