Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 128
Filtrar
1.
Radiat Res ; 197(1): 43-56, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33857285

RESUMO

Experimental mouse studies are important to gain a comprehensive, quantitative and mechanistic understanding of the biological factors that modify individual risk of radiation-induced health effects, including age at exposure, dose, dose rate, organ/tissue specificity and genetic factors. In this study, neonatal Ptch1+/- mice bred on CD1 and C57Bl/6 background received whole-body irradiation at postnatal day 2. This time point represents a critical phase in the development of the eye lens, cerebellum and dentate gyrus (DG), when they are also particularly susceptible to radiation effects. Irradiation was performed with γ rays (60Co) at doses of 0.5, 1 and 2 Gy, delivered at 0.3 Gy/min or 0.063 Gy/min. Wild-type and mutant mice were monitored for survival, lens opacity, medulloblastoma (MB) and neurogenesis defects. We identified an inverse genetic background-driven relationship between the radiosensitivity to induction of lens opacity and MB and that to neurogenesis deficit in Ptch1+/- mutants. In fact, high incidence of radiation-induced cataract and MB were observed in Ptch1+/-/CD1 mutants that instead showed no consequence of radiation exposure on neurogenesis. On the contrary, no induction of radiogenic cataract and MB was reported in Ptch1+/-/C57Bl/6 mice that were instead susceptible to induction of neurogenesis defects. Compared to Ptch1+/-/CD1, the cerebellum of Ptch1+/-/C57Bl/6 mice showed increased radiosensitivity to apoptosis, suggesting that differences in processing radiation-induced DNA damage may underlie the opposite strain-related radiosensitivity to cancer and non-cancer pathologies. Altogether, our results showed lack of dose-rate-related effects and marked influence of genetic background on the radiosensitivity of Ptch1+/-mice, supporting a major contribution of individual sensitivity to radiation risk in the population.


Assuntos
Meduloblastoma/etnologia , Neoplasias Induzidas por Radiação/etiologia , Animais , Relação Dose-Resposta à Radiação , Raios gama , Patrimônio Genético , Humanos , Cristalino/efeitos da radiação , Camundongos Endogâmicos C57BL , Neurogênese , Tolerância a Radiação , Irradiação Corporal Total
2.
Radiat Res ; 197(1): 22-35, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33857324

RESUMO

One harmful long-term effect of ionizing radiation is cataract development. Recent studies have been focused on elucidating the mechanistic pathways involved in this pathogenesis. Since accumulating evidence has established a role of microRNAs in ocular diseases, including cataract, the goal of this work was to determine the microRNA signature of the mouse lens, at short time periods postirradiation, to understand the mechanisms related to radio-induced cataractogenesis. To evaluate the differences in the microRNA profiles, 10-week-old Patched1 heterozygous (Ptch1+/-) mice, bred onto two different genetic backgrounds (CD1 and C57Bl/6J), received whole-body 2 Gy γ-ray irradiation, and 24 h later lenses were collected. Next-generation sequencing and bioinformatics analysis revealed that genetic background markedly influenced the list of the deregulated microRNAs and the mainly predicted perturbed biological functions of 2 Gy irradiated Ptch1+/- mouse lenses. We identified a subset of microRNAs with a contra-regulated expression between strains, with a key role in regulating Toll-like receptor (TLR)-signaling pathways. Furthermore, a detailed analysis of miRNome data showed a completely different DNA damage response in mouse lenses 24 h postirradiation, mainly mediated by a marked upregulation of p53 signaling in Ptch1+/-/C57Bl/6J lenses that was not detected on a CD1 background. We propose a strict interplay between p53 and TLR signaling in Ptch1+/-/C57Bl/6J lenses shortly after irradiation that could explain both the resistance of this strain to developing lens opacities and the susceptibility of CD1 background to radiation-induced cataractogenesis through activation of epithelial-mesenchymal transition.


Assuntos
Catarata/etiologia , Cristalino/efeitos da radiação , Animais , Dano ao DNA/efeitos da radiação , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Raios gama , Patrimônio Genético , Humanos , Camundongos Endogâmicos C57BL , MicroRNAs , Receptor Patched-1/metabolismo , Transdução de Sinais , Receptores Toll-Like/metabolismo , Irradiação Corporal Total
3.
Radiat Res ; 197(1): 57-66, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33984859

RESUMO

Recent epidemiological findings and reanalysis of historical data suggest lens opacities resulting from ionizing radiation exposures are likely induced at lower doses than previously thought. These observations have led to ICRP recommendations for a reduction in the occupational dose limits for the eye lens, as well as subsequent implementation in EU member states. The EU CONCERT LDLensRad project was initiated to further understand the effects of ionizing radiation on the lens and identify the mechanism(s) involved in radiation-induced cataract, as well as the impact of dose and dose-rate. Here, we present the results of a long-term study of changes to lens opacity in male and female adult mice from a variety of different genetic (radiosensitive or radioresistant) backgrounds, including mutant strains Ercc2 and Ptch1, which were assumed to be susceptible to radiation-induced lens opacities. Mice received 0.5, 1 and 2 Gy 60Co gamma-ray irradiation at dose rates of 0.063 and 0.3 Gy min-1. Scheimpflug imaging was used to quantify lens opacification as an early indicator of cataract, with monthly observations taken postirradiation for an 18-month period in all strains apart from 129S2, which were observed for 12 months. Opacification of the lens was found to increase with time postirradiation (with age) for most mouse models, with ionizing radiation exposure increasing opacities further. Sex, dose, dose rate and genetic background were all found to be significant contributors to opacification; however, significant interactions were identified, which meant that the impact of these factors was strain dependent. Mean lens density increased with higher dose and dose rate in the presence of Ercc2 and Ptch1 mutations. This project was the first to focus on low (<1 Gy) dose, multiple dose rate, sex and strain effects in lens opacification, and clearly demonstrates the importance of these experimental factors in radiobiological investigations on the lens. The results provide insight into the effects of ionizing radiation on the lens as well as the need for further work in this area to underpin appropriate radiation protection legislation and guidance.


Assuntos
Catarata/etiologia , Animais , Feminino , Patrimônio Genético , Humanos , Cristalino/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Exposição Ocupacional , Receptor Patched-1/metabolismo , Doses de Radiação , Exposição à Radiação , Radiação Ionizante , Proteína Grupo D do Xeroderma Pigmentoso/metabolismo
4.
J Biol Regul Homeost Agents ; 35(3): 847-863, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34155874

RESUMO

Respiratory infections (RI) significantly burden patients, their families, and society. Respiratory infection recurrence (RRI) usually depends on a defect of the immune response, which can be more or less transient and/or selective. In particular, children, older people, heavy smokers, and patients with chronic diseases, characterized by an inadequate immune response, may be at risk of developing RRI. In this context, OM- 85 could represent a valuable option in the management of RRI. OM-85 is a bacterial lysate containing the extracts of some common pathogens, including Branhamella catarrhalis, Klebsiella pneumoniae, Klebsiella ozaenae, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus viridans, and Staphylococcus aureus. Methodologically rigorous studies have documented the mechanism of action, efficacy, and safety of OM-85. OM-85 enhances the natural and acquired immune response through multifaceted mechanisms. Substantial evidence has shown that OM-85 can prevent respiratory infections, reduce the number of COPD exacerbations, and shorten the disease duration at home or in hospital. OM-85 can enhance the effectiveness of the 'flu vaccination without affecting the vaccine tolerability. The preventive use of OM-85 can reduce the use of antibiotics, contributing to contrast antibiotic resistance and saving the high cost of chronic respiratory diseases. Further studies should define the ideal candidate to OM-85 treatment.


Assuntos
Klebsiella , Infecções Respiratórias , Idoso , Criança , Humanos , Moraxella catarrhalis , Infecções Respiratórias/prevenção & controle , Streptococcus pneumoniae
5.
QJM ; 114(9): 642-647, 2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33486512

RESUMO

BACKGROUND: COVID-19 has challenged the health system organization requiring a fast reorganization of diagnostic/therapeutic pathways for patients affected by time-dependent diseases such as acute coronary syndromes (ACS). AIM: To describe ACS hospitalizations, management, and complication rate before and after the COVID-19 pandemic was declared. DESIGN: Ecological retrospective study. Methods: We analyzed aggregated epidemiological data of all patients > 18 years old admitted for ACS in twenty-nine hub cardiac centers from 17 Countries across 4 continents, from December 1st, 2019 to April 15th, 2020. Data from December 2018 to April 2019 were used as historical period. RESULTS: A significant overall trend for reduction in the weekly number of ACS hospitalizations was observed (20.2%; 95% confidence interval CI [1.6, 35.4] P = 0.04). The incidence rate reached a 54% reduction during the second week of April (incidence rate ratio: 0.46, 95% CI [0.36, 0.58]) and was also significant when compared to the same months in 2019 (March and April, respectively IRR: 0.56, 95%CI [0.48, 0.67]; IRR: 0.43, 95%CI [0.32, 0.58] p < 0.001). A significant increase in door-to-balloon, door-to-needle, and total ischemic time (p <0.04 for all) in STEMI patents were reported during pandemic period. Finally, the proportion of patients with mechanical complications was higher (1.98% vs. 0.98%; P = 0.006) whereas GRACE risk score was not different. CONCLUSIONS: Our results confirm that COVID-19 pandemic was associated with a significant decrease in ACS hospitalizations rate, an increase in total ischemic time and a higher rate of mechanical complications on a international scale.


Assuntos
Síndrome Coronariana Aguda , COVID-19 , Síndrome Coronariana Aguda/epidemiologia , Síndrome Coronariana Aguda/terapia , Adolescente , Hospitalização , Humanos , Pandemias , Estudos Retrospectivos , SARS-CoV-2
6.
J Asthma ; 58(9): 1186-1193, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-32508174

RESUMO

INTRODUCTION: Although the long term negative effects of bronchopulmonary dysplasia (BPD) are well known, follow-up studies of preterm infants with BPD into childhood are lacking. METHODS: Forty-two preschool children (age range 3-6 years) who were born before 32 weeks of gestational age and affected by BPD were enrolled. Pre-, peri-, and post-natal data were collected. During the follow up appointment complete physical examination and lung function (impulse oscillometry (IOS)) were recorded. The European Community Respiratory Health Survey (ECRHS) questionnaire was administered to all enrolled subjects. RESULTS: Thirty patients were included in the final analysis. The BPD group did not differ in comparison to the non-BPD group in terms of lung function (p > 0.05). By comparing all subjects enrolled, We detected extremely low-birth-weight (ELBW) infants with height-, weight-, and gender-related reference values and a significant trend of increasing resistance values (R5Hz, R5-20 Hz) and respiratory impedance (Z5Hz) (p < 0.05). No significant difference in bronchial reversibility test was observed among BPD non-BPD groups (p < 0.05). The frequency of gastroesophageal reflux disease was significantly higher in patients with BPD when compared to non-BPD group (p < 0.05). Significant differences in gestational age, oxygen supplementation (days), mechanical ventilation therapy (days), and sepsis between BPD and non-BPD groups were also observed (p < 0.05). There were no significant differences in the prevalence of family and personal history of atopy and/or allergic diseases, tobacco exposure, respiratory symptoms, respiratory syncytial virus bronchiolitis, exercise induced dyspnea, treatment with ß-2 bronchodilators and inhaled corticosteroids among the groups (p > 0.05). CONCLUSIONS: The respiratory function in preschool children born with ELBW is characterized by an increase in impedance and resistance of small airways. No statistically significant differences were found between ELBW children with BPD and without BPD. With regards to the smallest gestational age, the longer duration of O2 therapy during hospitalization, and sepsis significantly resulted in a worse respiratory function.


Assuntos
Displasia Broncopulmonar/fisiopatologia , Pulmão/fisiopatologia , Resistência das Vias Respiratórias , Displasia Broncopulmonar/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Impedância Elétrica , Feminino , Inquéritos Epidemiológicos , Humanos , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Oscilometria , Oxigênio/uso terapêutico , Projetos Piloto , Respiração Artificial , Testes de Função Respiratória , Sepse/epidemiologia
7.
Allergol. immunopatol ; 48(6): 753-762, nov.-dic. 2020. tab
Artigo em Inglês | IBECS | ID: ibc-199267

RESUMO

Histamine is a chemical mediator, released predominantly by tissue mast cells, circulating basophils, and neurons, which are activated in response to various immunological and non-immunological stimuli. Histamine has to bind to specific receptors to exert its physiological and pathophysiological functions. Endogenous histamine is the main mediator of the immediate allergic response, which moreover, performs other multiple functions, including regulation of gastric secretion, neurotransmission in the central nervous system, and immunomodulatory activity. The involvement of histamine in various disorders and the importance of receptors in the clinical features have relevant implications in clinical practice. Anti-H1 antihistamines contrast the histamine-dependent effects, mainly concerning nasal symptoms and cutaneous itching and wheal. Antihistamines are among the most prescribed drugs in pediatric care. This review updates the practical use of antihistamines in children and adolescents


No disponible


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Antagonistas dos Receptores Histamínicos/farmacologia , Antagonistas dos Receptores Histamínicos/uso terapêutico , Antagonistas dos Receptores Histamínicos/classificação , Rinite Alérgica/tratamento farmacológico , Conjuntivite Alérgica/tratamento farmacológico , Urticária/tratamento farmacológico , Dermatite Atópica/tratamento farmacológico , Asma/tratamento farmacológico , Anafilaxia/tratamento farmacológico
8.
Allergol Immunopathol (Madr) ; 48(6): 753-762, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32448753

RESUMO

Histamine is a chemical mediator, released predominantly by tissue mast cells, circulating basophils, and neurons, which are activated in response to various immunological and non-immunological stimuli. Histamine has to bind to specific receptors to exert its physiological and pathophysiological functions. Endogenous histamine is the main mediator of the immediate allergic response, which moreover, performs other multiple functions, including regulation of gastric secretion, neurotransmission in the central nervous system, and immunomodulatory activity. The involvement of histamine in various disorders and the importance of receptors in the clinical features have relevant implications in clinical practice. Anti-H1 antihistamines contrast the histamine-dependent effects, mainly concerning nasal symptoms and cutaneous itching and wheal. Antihistamines are among the most prescribed drugs in pediatric care. This review updates the practical use of antihistamines in children and adolescents.


Assuntos
Antialérgicos/uso terapêutico , Antagonistas dos Receptores Histamínicos/uso terapêutico , Hipersensibilidade/tratamento farmacológico , Guias de Prática Clínica como Assunto , Adolescente , Alergia e Imunologia/normas , Antialérgicos/farmacologia , Criança , Histamina/metabolismo , Antagonistas dos Receptores Histamínicos/farmacologia , Humanos , Hipersensibilidade/imunologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia
9.
Respir Med ; 164: 105906, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32217291

RESUMO

BACKGROUND: Nocturnal hypoxemia adversely affects outcomes in patients with cystic fibrosis (CF). Although an early detection of this abnormality may be desirable, still its predictability remains uncertain. The Lung Clearance Index (LCI) is a measure of lung ventilation distribution obtained from a multiple-breath washout technique (MBW), recently implemented in patients with CF. This study aimed to establish whether the LCI predicts nocturnal hypoxemia in patients with stable CF, with mild to moderate disease, and normal diurnal gas exchange. METHODS: 31 stable patients (15 males, mean age 17.4 ± 5.2 years) with mild to moderate CF, normoxic when awake, were enrolled. In all patients we performed nocturnal cardio-respiratory polygraphy, lung function measurement, and MBW test to derive LCI values. RESULTS: LCI was abnormal in most of the patients and inversely correlated with mean nocturnal SpO2 (r = -0.880 p < 0.01). A receiver operating characteristic (ROC) analysis, performed to assess whether LCI predicted nocturnal hypoxemia, revealed a high predictive accuracy of LCI for nocturnal desaturation (AUC = 0.96; Youden index = 0.79). Forced expiratory volume in 1 s (FEV1) was predictive only in patients with more severe airway obstruction, with a moderate degree of accuracy (AUC 0.71). CONCLUSIONS: The LCI showed a high effectiveness in predicting nocturnal hypoxemia in stable patients with CF, particularly when compared with a traditional parameter of lung function such as FEV1.


Assuntos
Fibrose Cística/complicações , Hipóxia/diagnóstico , Hipóxia/etiologia , Pulmão/metabolismo , Ventilação Pulmonar , Testes de Função Respiratória/métodos , Adolescente , Criança , Fibrose Cística/fisiopatologia , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Polissonografia , Valor Preditivo dos Testes , Testes de Função Respiratória/tendências , Índice de Gravidade de Doença , Adulto Jovem
10.
Anal Bioanal Chem ; 411(29): 7681-7688, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31286178

RESUMO

A new electrochemical sensor, based on NdFeO3 nanoparticles as electrocatalytic material, was proposed here for the detection of dopamine (DA). NdFeO3 nanoparticles were first synthesized by a simple thermal treatment method and subsequent annealing at high temperature (700 °C). The prepared electrocatalytic material has been characterized in detail by SEM-EDX, XRD, and Raman techniques. Characterization results display its sheet-like morphology, constituted by a porous network of very small orthorhombic NdFeO3 nanoparticles. NdFeO3 electrocatalytic material was then used to modify the working electrode of screen-printed carbon electrodes (SPCEs). Electrochemical tests demonstrated that NdFeO3- modified screen-printed carbon electrode (NdFeO3/SPCE) exhibited a remarkable enhancement of the dopamine electrooxidation, compared to the bare SPCE one. The analytical performance of the developed sensor has been evaluated for the detection of this analyte by means of the square-wave voltammetry (SWV) technique. The modified electrode showed two linear concentration ranges, from 0.5 to 100 µM and 150 to 400 µM, respectively, a limit of detection (LOD) of 0.27 µM (at S/N = 3), and good reproducibility, stability, and selectivity. Additionally, we also report an attempt made to propose the modified sensor for the simultaneous detection of dopamine and uric acid (UA). The procedure was also applied for the determination of dopamine in spiked real samples. So, this paper reports for the first time the use of a modified NdFeO3 screen-printed electrode for developing an electrochemical sensor for the quantification of important biomolecules. Graphical abstract.


Assuntos
Dopamina/análise , Técnicas Eletroquímicas/instrumentação , Compostos Férricos/química , Neodímio/química , Técnicas Biossensoriais , Catálise , Eletrodos , Humanos , Limite de Detecção , Reprodutibilidade dos Testes , Ácido Úrico/análise
11.
Ann Bot ; 124(5): 849-860, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31361802

RESUMO

BACKGROUND AND AIMS: At the rear edge of the distribution of species, extreme isolation and small population size influence the genetic diversity and differentiation of plant populations. This may be particularly true for Arctic-alpine species in mid-latitude mountains, but exactly how peripherality has shaped their genetic and reproductive characteristics is poorly investigated. The present study, focused on Salix herbacea, aims at providing new insights into the causes behind ongoing demographic dynamics and their consequences for peripheral populations of Arctic-alpine species. METHODS: We performed a whole-population, highly detailed sampling of the only two S. herbacea populations in the northern Apennines, comparing their clonal and genetic diversity, sex ratio and spatial genetic structure with a reference population from the Alps. After inspecting ~1800 grid intersections in the three populations, 563 ramets were genotyped at 11 nuclear microsatellite markers (nSSRs). Past demography and mating patterns of Apennine populations were investigated to elucidate the possible causes of altered reproductive dynamics. KEY RESULTS: Apennine populations, which experienced a Holocene bottleneck and are highly differentiated (FST = 0.15), had lower clonal and genetic diversity compared with the alpine population (RMLG = 1 and HE = 0.71), with the smaller population exhibiting the lowest diversity (RMLG = 0.03 and HE = 0.24). An unbalanced sex ratio was found in the larger (63 F:37 M) and the smaller (99 F:1 M) Apennine population. Both were characterized by the presence of extremely large clones (up to 2500 m2), which, however, did not play a dominant role in local reproductive dynamics. CONCLUSIONS: Under conditions of extreme isolation and progressive size reduction, S. herbacea has experienced an alteration of genetic characteristics produced by the prevalence of clonal growth over sexual reproduction. However, our results showed that the larger Apennine population has maintained levels of sexual reproduction enough to counteract a dramatic loss of genetic and clonal diversity.


Assuntos
Salix , Regiões Árticas , Variação Genética , Genética Populacional , Genótipo , Repetições de Microssatélites , Reprodução
12.
DNA Repair (Amst) ; 74: 70-79, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30606609

RESUMO

DSBs are harmful lesions produced through endogenous metabolism or by exogenous agents such as ionizing radiation, that can trigger genomic rearrangements. We have recently shown that exposure to 2 Gy of X-rays has opposite effects on the induction of Shh-dependent MB in NHEJ- and HR-deficient Ptch1+/- mice. In the current study we provide a comprehensive link on the role of HR/NHEJ at low doses (0.042 and 0.25 Gy) from the early molecular changes through DNA damage processing, up to the late consequences of their inactivation on tumorigenesis. Our data indicate a prominent role for HR in genome stability, by preventing spontaneous and radiation-induced oncogenic damage in neural precursors of the cerebellum, the cell of origin of MB. Instead, loss of DNA-PKcs function increased DSBs and apoptosis in neural precursors of the developing cerebellum, leading to killing of tumor initiating cells, and suppression of MB tumorigenesis in DNA-PKcs-/-/Ptch1+/- mice. Pathway analysis demonstrates that DNA-PKcs genetic inactivation confers a remarkable radiation hypersensitivity, as even extremely low radiation doses may deregulate many DDR genes, also triggering p53 pathway activation and cell cycle arrest. Finally, by showing that DNA-PKcs inhibition by NU7441 radiosensitizes human MB cells, our in vitro findings suggest the inclusion of MB in the list of tumors beneficiating from the combination of radiotherapy and DNA-PKcs targeting, holding promise for clinical translation.


Assuntos
Neoplasias Cerebelares/genética , Reparo do DNA/efeitos da radiação , Meduloblastoma/genética , Neoplasias Induzidas por Radiação/genética , Receptor Patched-1/deficiência , Receptor Patched-1/metabolismo , Animais , Carcinogênese/genética , Carcinogênese/efeitos da radiação , Linhagem Celular Tumoral , Neoplasias Cerebelares/metabolismo , Neoplasias Cerebelares/patologia , Neoplasias Cerebelares/terapia , Dano ao DNA , Reparo do DNA por Junção de Extremidades/efeitos da radiação , DNA Helicases/genética , Proteína Quinase Ativada por DNA/deficiência , Proteínas de Ligação a DNA/deficiência , Relação Dose-Resposta à Radiação , Recombinação Homóloga/efeitos da radiação , Humanos , Meduloblastoma/metabolismo , Meduloblastoma/patologia , Meduloblastoma/terapia , Camundongos , Terapia de Alvo Molecular , Mutação , Neoplasias Induzidas por Radiação/metabolismo , Neoplasias Induzidas por Radiação/patologia , Neoplasias Induzidas por Radiação/terapia , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Risco , Raios X/efeitos adversos
13.
Nanotechnology ; 30(5): 055502, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30517085

RESUMO

Ternary nanocomposites made of γ-iron oxide and aluminum-doped zinc oxide (γ-Fe2O3/Al-ZnO NCs), with different metal oxides ratio (0%-100%) were prepared through a solvothermal sol-gel process. The synthesized materials were characterized by x-ray diffraction, UV-vis spectroscopy, photoluminescence (PL), scanning electron microscope and BET analysis. Characterization results demonstrated that the ternary γ-Fe2O3/Al-ZnO NCs are mainly constituted by γ-Fe2O3 and Al-ZnO individual phases, while structural and physical properties like surface area, pore size, optical band gap, PL and electrical conductivity were deeply affected by the composition of nanocomposite. The synthesized γ-Fe2O3/Al-ZnO NCs were employed to prepare conductometric gas sensors, then their sensing performances toward acetone were also investigated. Results revealed enhanced sensing performance of nanocomposites than both pure γ-Fe2O3 and Al-ZnO phases. In particular, the γ-Fe2O3(33%)/Al-ZnO based gas sensor showed the best sensing properties, like a high response of R air/R gas = 29, a short response time of 3 s, in addition to an improved selectivity toward acetone versus ethanol at an operating temperature of 200 °C. Overall, ternary γ-Fe2O3/Al-ZnO NCs appear to be promising for the development of conductometric acetone sensors.

14.
Radiat Prot Dosimetry ; 183(1-2): 151-155, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30520994

RESUMO

The advent of new 'omics' techniques determined a massive boost in the measurement of the whole spectra of molecules within cells, favoring promising new radiobiological studies at low doses. The main aim of this work was to assess the radiation-induced perturbations of miRNA profiles and their temporal dynamics. Human Umbilical Vein Endothelial Cells were irradiated with low doses of γ-rays. At different time points post-irradiation, cells were harvested and miRNAs isolated. A full mapping of the miRNA sequences via Next-Generation-Sequencing analysis was performed followed by bioinformatic analyses. Pathway enrichment analyses on the differentially expressed miRNAs focused both on the averaged effects of different doses over the 24-h experiment and on the altered temporal dynamics of the miRNA profiles. These complementary analyses provided a picture of the dose- and time-dependent miRNAs responses, allowing to better explore the candidate biomarkers linked to radiation exposures and their corresponding pathways and functions.


Assuntos
MicroRNAs/efeitos da radiação , Veias Umbilicais/citologia , Biomarcadores/análise , Biologia Computacional , Relação Dose-Resposta à Radiação , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Fatores de Tempo , Raios X
15.
Acta Paediatr ; 108(4): 740-744, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30194783

RESUMO

AIM: This study determined cardiovascular impairment in young children with obstructive respiratory disease who were assessed using the opening interrupter technique (RINT). METHODS: This pilot study enrolled 41 children who had been referred to pulmonology and allergology specialists at the University of Catania, Italy, from March to July 2017: 23 (mean age 4.13 ± 0.62 years) had chronic coughs and wheezing and 18 controls (mean age 4.27 ± 0.66 years) had obstructive chest disease, but were otherwise healthy. Airway resistance was evaluated using RINT and cardiac function by studying the ejection fraction, pulmonary artery systolic pressure (PASP), tricuspid annular plane systolic excursion and tricuspid flow propagation velocity (TFPV). RESULTS: The RINT and PASP values were significantly higher in the patient group when compared to the controls, but the TFPV values were lower. A direct and significant Spearman's correlation coefficient (r) between RINT and PASP values was observed (r = 0.81). We found a significant inverse correlation between RINT and TFPV (r = -0.83), as well as TFPV and PASP (r = -0.78). CONCLUSION: This study showed that children with obstructive respiratory diseases had a major risk of cardiovascular impairment. Impaired diastolic function of the right ventricle occurred very early when airway resistance was abnormally increased.


Assuntos
Diástole , Transtornos Respiratórios/complicações , Transtornos Respiratórios/fisiopatologia , Disfunção Ventricular Direita/etiologia , Resistência das Vias Respiratórias , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Masculino , Projetos Piloto
16.
J Dairy Sci ; 101(1): 649-660, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29102142

RESUMO

The objective of this study was to develop a method to quantify the milking conditions under which circulatory impairment of teat tissues occurs during the peak flow period of milking. A secondary objective was to quantify the effect of the same milking conditions on milk flow rate during the peak flow rate period of milking. Additionally, the observed milk flow rate was a necessary input to the calculation of canal area, our quantitative measure of circulatory impairment. A central composite experimental design was used with 5 levels of each of 2 explanatory variables (system vacuum and pulsator ratio), creating 9 treatments including the center point. Ten liners, representing a wide range of liner compression (as indicated by overpressure), were assessed, with treatments applied using a novel quarter-milking device. Eight cows (32 cow-quarters) were used across 10 separate evening milkings, with quarter being the experimental unit. The 9 treatments, with the exception of a repeated center point, were randomly applied to all quarters within each individual milking. Analysis was confined to the peak milk flow period. Milk flow rate (MFR) and teat canal cross sectional area (CA) were normalized by dividing individual MFR, or CA, values by their within-quarter average value across all treatments. A multiple explanatory variable regression model was developed for normalized MFR and normalized CA. The methods presented in this paper provided sufficient precision to estimate the effects of vacuum (both at teat-end and in the liner mouthpiece), pulsation, and liner compression on CA, as an indicator of teat-end congestion, during the peak flow period of milking. Liner compression (as indicated by overpressure), teat-end vacuum, vacuum in the liner mouthpiece, milk-phase time, and their interactions are all important predictors of MFR and teat-end congestion during the peak milk flow period of milking. Increasing teat-end vacuum and milk-phase time increases MFR and reduces CA (indicative of increased teat-end congestion). Increasing vacuum in the liner mouthpiece also acts to reduce CA and MFR. Increasing liner compression reduces the effects of teat-end congestion, resulting in increased MFR and increased CA at high levels of teat-end vacuum and milk-phase time. These results provide a better understanding of the balance between milking speed and milking gentleness.


Assuntos
Indústria de Laticínios/instrumentação , Indústria de Laticínios/métodos , Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Animais , Bovinos , Feminino , Leite , Fatores de Tempo , Vácuo
17.
Cytokine ; 99: 43-49, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28692864

RESUMO

BACKGROUND: Although several studies suggest a possible link between dyslipidemia and atopy, literature findings are still unclear. OBJECTIVE: The aim of the study was to investigate the relationship between dyslipidemia and atopy in a pediatric population affected by dyslipidemia or dyslipidemia/atopic predisposition. MATERIALS AND METHODS: Children with dyslipidemia, dyslipidemia and atopy as well as healthy children were recruited. Serum total IgE, IL-10, IL-17, and IL-23 levels as well as fasting lipid values (total cholesterol, LDL, HDL and triglycerides) were performed on all enrolled children. RESULTS: The present study evaluated 23 patients affected by dyslipidemia, 26 patients affected by atopy and dyslipidemia and, 22healthy children. Serum total IgE levels significantly related also with serum cholesterol levels: positively with total cholesterol (p<0.05), LDL (p<0.05), and tryglicerides (p<0.001), but negatively with HDL (p<0.05). Serum levels of IL-10 were lower in children with atopy and dyslipidemia than patients with dyslipidemia (p<0.001). Serum IL-10 levels significantly related also with serum cholesterol levels: negatively with total cholesterol (p<0.001), LDL (p<0.05), and triglycerides (p<0.05), but positively with HDL (p<0.05). Serum IL-17 and IL-23 levels showed the same trend. They were significantly higher in children with atopy and dyslipidemia than patients with dyslipidemia (p<0.001). In particular, serum IL-17 and IL-23 values positively correlated with serum total IgE levels (p<0.05); serum total cholesterol levels (p<0.001); serum LDL levels (p<0.001); serum triglycerides levels (p<0.05). Although not statistically significant, an inverse correlation has been noted between serum IL-17, IL-23 and HDL levels. CONCLUSIONS: These findings support the notion that dyslipidemia and atopic predisposition share the same immune pathways as well as they offer new insights in the complex crosstalk between hyperlipidemia and atopy.


Assuntos
Dislipidemias/sangue , Hipersensibilidade Imediata/sangue , Interleucina-10/sangue , Interleucina-17/sangue , Interleucina-23/sangue , Estudos de Casos e Controles , Criança , Colesterol/sangue , Feminino , Humanos , Imunoglobulina E/sangue , Masculino
18.
Philos Trans A Math Phys Eng Sci ; 375(2091)2017 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-28265029

RESUMO

The dynamics of the velocity field resulting from the interaction between the atmospheric boundary layer and a wind turbine array can affect significantly the performance of a wind power plant and the durability of wind turbines. In this work, dynamics in wind turbine wakes and instabilities of helicoidal tip vortices are detected and characterized through modal decomposition techniques. The dataset under examination consists of snapshots of the velocity field obtained from large-eddy simulations (LES) of an isolated wind turbine, for which aerodynamic forcing exerted by the turbine blades on the atmospheric boundary layer is mimicked through the actuator line model. Particular attention is paid to the interaction between the downstream evolution of the helicoidal tip vortices and the alternate vortex shedding from the turbine tower. The LES dataset is interrogated through different modal decomposition techniques, such as proper orthogonal decomposition and dynamic mode decomposition. The dominant wake dynamics are selected for the formulation of a reduced order model, which consists in a linear time-marching algorithm where temporal evolution of flow dynamics is obtained from the previous temporal realization multiplied by a time-invariant operator.This article is part of the themed issue 'Wind energy in complex terrains'.

19.
Nanotechnology ; 28(13): 135501, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28165331

RESUMO

In this study, we report the preparation of a novel nanocomposite, 5-aza[5]helicene-CH2O-CO-MWCNTs, obtained by grafting the 5-aza[5]helicene moiety on the surface of multi-walled carbon nanotubes (MWCNTs). Thermogravimetry (TGA), Fourier transform-infrared spectroscopy (FTIR), ultraviolet (UV), and photoluminescence (PL) measurements provided evidence that the organic moiety is covalently grafted to the MWCNTs. The 5-aza[5]helicene-CH2O-CO-MWCNTs nanocomposite was utilized to fabricate modified commercial screen-printed carbon electrodes. Its electrochemical behavior was studied in neutral buffer solution in the presence of ferricyanide and hydroquinone (HQ). Finally, the electrochemical sensing of epinephrine in the presence of ascorbic acid by using the linear sweep voltammetry (LSV) technique was investigated. Results have demonstrated the enhanced electrocatalytic activity and excellent ability of the 5-aza[5]helicene-CH2O-CO-MWCNTs-modified electrode in the separation between the anodic peaks of epinephrine (EP) and ascorbic acid (AA), even in the presence of a high amount of AA, with a detection limit (S/N = 3) of 5 µmol l-1.

20.
Nanotechnology ; 27(38): 385502, 2016 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-27532479

RESUMO

In recent years, SnO2 nanoparticles (NPs) have been subjected to various modifications in order to improve their performance in sensing and other applications. Here, we report the synthesis of SnO2 NPs by microwave irradiation, and subsequent exposure to gamma (γ) radiation at different doses (0-150 kGy) to induce desirable physico-chemical properties. The irradiated samples were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM and HR-TEM), and photoluminescence (PL) to evaluate the effect of γ-ray irradiation on their morphology and microstructure. The results revealed that the bulk crystal structure remained unchanged after irradiation, while the existence of defects and a damaged over-layer have been confirmed by PL and HR-TEM respectively. The influence of γ-irradiation on the electrical and CO sensing characteristics was also investigated in the temperature range between 150 and 400 °C. γ-irradiated SnO2 NP based resistive sensors showed better CO sensing characteristics (i.e. higher response and lower working temperature) compared to non-irradiated SnO2. Upon optimizing the γ-ray dose irradiation level and working temperature, a ten-fold enhancement in the response to CO has been achieved (R/R 0 = 12 to 50 ppm of CO in air) in 50 kGy irradiated SnO2 NP based sensors operating at 150 °C. A possible mechanism for the enhanced sensing performance of γ-irradiated SnO2 NPs has been proposed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...