Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ying Yong Sheng Tai Xue Bao ; 33(5): 1223-1232, 2022 May.
Artigo em Chinês | MEDLINE | ID: mdl-35730080

RESUMO

Phenol oxidase plays an important role in the degradation of soil organic matter. There was no standard method to determine soil phenol oxidase activity. To fill such knowledge gap, we investigated the effects of substrate type, pH, soil storage conditions, storage time, substrate concentration, water-soil ratio, incubation time and incubation temperature on soil phenol oxidase activity in three different subtropical forest soils developed on sandstone. The pH of extraction buffers significantly affected the phenol oxidase activity. Using 2,2'-azinobis-(-3-ethylbenzo-thiazoline-6-sulfononic acid)-diammonium salt (ABTS) as substrate acquired higher oxidase activity and was applicable to wider pH range than using 3-(3,4-Dihydroxyphenyl)-L-alanine (L-DOPA) as substrate, indicating that ABTS was more suitable as a substrate for measuring phenol oxidase activity in acidic soils of subtropical forests. The storage condition significantly affected phenol oxidase activity. The phenol oxidase activity declined with time in all the three types of soil. The decreasing rate was air-dried > 4 ℃ refrigerated > -20 ℃ frozen > -80 ℃ frozen, suggesting that the frozen storage method was better than others in maintaining soil phenol oxidase activity if the determination of phenol oxidase activity in fresh soil samples cannot be immediately done. Substrate concentration, water-soil ratio, and incubation time and temperature all affected the activity of soil phenol oxidase. The condition of soil: buffer ratio of 1:100, 2 mmol·L-1 concentration of ABTS with an incubation time of 4 h at 25-30 ℃ was optimal for measuring phenol oxidase activity in acidic soils of subtropical forests, with high repeatability and sensitivity.


Assuntos
Monofenol Mono-Oxigenase , Solo , China , Florestas , Microbiologia do Solo , Água
2.
Cell Death Discov ; 8(1): 18, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013123

RESUMO

Acute lung injury (ALI) represents a frequent sepsis-induced inflammatory disorder. Mesenchymal stromal cells (MSCs) elicit anti-inflammatory effects in sepsis. This study investigated the mechanism of exosomes from adipose-derived MSCs (ADMSCs) in sepsis-induced ALI. The IL-27r-/- (WSX-1 knockout) or wild-type mouse model of sepsis was established by cecal ligation and puncture (CLP). The model mice and lipopolysaccharide (LPS)-induced macrophages were treated with ADMSC-exosomes. The content of Dil-labeled exosomes in pulmonary macrophages, macrophages CD68+ F4/80+ in whole lung tissues, and IL-27 content in macrophages were detected. The mRNA expression and protein level of IL27 subunits P28 and EBI3 in lung tissue and the levels of IL-6, TNF-α, and IL-1ß were measured. The pulmonary edema, tissue injury, and pulmonary vascular leakage were measured. In vitro, macrophages internalized ADMSC-exosomes, and ADMSC-exosomes inhibited IL-27 secretion in LPS-induced macrophages. In vivo, IL-27 knockout attenuated CLP-induced ALI. ADMSC-exosomes suppressed macrophage aggregation in lung tissues and inhibited IL-27 secretion. ADMSC-exosomes decreased the contents of IL-6, TNF-α, and IL-1ß, reduced pulmonary edema and pulmonary vascular leakage, and improved the survival rate of mice. Injection of recombinant IL-27 reversed the protective effect of ADMSC-exosomes on sepsis mice. Collectively, ADMSC-exosomes inhibited IL-27 secretion in macrophages and alleviated sepsis-induced ALI in mice.

3.
Front Plant Sci ; 12: 705861, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34394162

RESUMO

Climate warming is becoming an increasingly serious threat. Understanding plant stoichiometry changes under climate warming is crucial for predicting the effects of future warming on terrestrial ecosystem productivity. Nevertheless, how plant stoichiometry responds to warming when interannual rainfall variation is considered, remains poorly understood. We performed a field soil warming experiment (+5°C) using buried heating cables in subtropical areas of China from 2015 to 2018. Stoichiometric patterns of foliar C:N:P:K:Ca:Mg, non-structural carbohydrate, and stable isotope of Cunninghamia lanceolata seedlings were studied. Our results showed that soil warming decreased foliar P and K concentrations, C:Ca, P:Ca, and P:Mg ratios. However, soil warming increased foliar Ca concentration, δ15N value, C:P and N:P ratios. The response ratios of foliar N, C:N, and δ15N to soil warming were correlated with rainfall. Our findings indicate that there was non-homeostasis of N and C:N under warming conditions. Three possible reasons for this result are considered and include interannual variations in rainfall, increased loss of N, and N limitation in leaves. Piecewise structural equation models showed that stoichiometric non-homeostasis indirectly affected the growth of C. lanceolata seedlings in response to soil warming. Consequently, the growth of C. lanceolata seedlings remained unchanged under the warming treatment. Taken together, our results advance the understanding of how altered foliar stoichiometry relates to changes in plant growth in response to climate warming. Our results emphasize the importance of rainfall variations for modulating the responses of plant chemical properties to warming. This study provides a useful method for predicting the effects of climate warming on economically important timber species.

4.
Front Genet ; 12: 691391, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34306031

RESUMO

Hepatocellular carcinoma (HCC), one of the most common and lethal tumors worldwide, is usually not diagnosed until the disease is advanced, which results in ineffective intervention and unfavorable prognosis. Small molecule targeted drugs of HCC, such as sorafenib, provided only about 2.8 months of survival benefit, partially due to cancer stem cell resistance. There is an urgent need for the development of new treatment strategies for HCC. Tumor immunotherapies, including immune check point inhibitors, chimeric antigen receptor T cells (CAR-T) and bispecific antibodies (BsAb), have shown significant potential. It is known that the expression level of glypican-3 (GPC3) was significantly increased in HCC compared with normal liver tissues. A bispecific antibody (GPC3-S-Fabs) was reported to recruit NK cells to target GPC3 positive cancer cells. Besides, bispecific T-cell Engagers (BiTE), including GPC3/CD3, an aptamer TLS11a/CD3 and EpCAM/CD3, were recently reported to efficiently eliminate HCC cells. It is known that immune checkpoint proteins programmed death-1 (PD-1) binding by programmed cell death-ligand 1 (PD-L1) activates immune checkpoints of T cells. Anti-PD-1 antibody was reported to suppress HCC progression. Furthermore, GPC3-based HCC immunotherapy has been shown to be a curative approach to prolong the survival time of patients with HCC in clinically trials. Besides, the vascular endothelial growth factor (VEGF) inhibitor may inhibit the migration, invasion and angiogenesis of HCC. Here we review the cutting-edge progresses on mechanisms and clinical trials of HCC immunotherapy, which may have significant implication in our understanding of HCC and its immunotherapy.

5.
Oncol Rep ; 46(1)2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34080662

RESUMO

Cell­cell fusion is a dynamic biological phenomenon, which plays an important role in various physiological processes, such as tissue regeneration. Similarly, normal cells, particularly bone marrow­derived cells (BMDCs), may attempt to fuse with cancer cells to rescue them. The rescue may fail, but the fused cells end up gaining the motility traits of BMDCs and become metastatic due to the resulting genomic instability. In fact, cell­cell fusion was demonstrated to occur in vivo in cancer and was revealed to promote tumor metastasis. However, its existence and role may be underestimated, and has not been widely acknowledged. In the present review, the milestones in cell fusion research were highlighted, the evidence for cell­cell fusion in vitro and in vivo in cancer was evaluated, and the current understanding of the molecular mechanisms by which cell­cell fusion occurs was summarized, to emphasize their important role in tumor metastasis. The summary provided in the present review may promote further study into this process and result in novel discoveries of strategies for future treatment of tumor metastasis.


Assuntos
Instabilidade Genômica , Metástase Neoplásica/patologia , Animais , Fusão Celular , Redes Reguladoras de Genes , Humanos , Metástase Neoplásica/genética
6.
Glob Chang Biol ; 27(10): 2039-2048, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33559308

RESUMO

Optimal methods for incorporating soil microbial mechanisms of carbon (C) cycling into Earth system models (ESMs) are still under debate. Specifically, whether soil microbial physiology parameters and residual materials are important to soil organic C (SOC) content is still unclear. Here, we explored the effects of biotic and abiotic factors on SOC content based on a survey of soils from 16 locations along a ~4000 km forest transect in eastern China, spanning a wide range of climate, soil conditions, and microbial communities. We found that SOC was highly correlated with soil microbial biomass C (MBC) and amino sugar (AS) concentration, an index of microbial necromass. Microbial C use efficiency (CUE) was significantly related to the variations in SOC along this national-scale transect. Furthermore, the effect of climatic and edaphic factors on SOC was mainly via their regulation on microbial physiological properties (CUE and MBC). We also found that regression models on explanation of SOC variations with microbial physiological parameters and AS performed better than the models without them. Our results provide the empirical linkages among climate, microbial characteristics, and SOC content at large scale and confirm the necessity of incorporating microbial biomass and necromass pools in ESMs under global change scenarios.


Assuntos
Carbono , Solo , Carbono/análise , China , Florestas , Microbiologia do Solo
7.
Ying Yong Sheng Tai Xue Bao ; 32(1): 16-22, 2021 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-33477208

RESUMO

With the aim to understand the influence degree and mechanism of parent material and forest type on soil phosphorus component, we analyzed soil P fractions, iron and aluminum oxides, microbial biomass, and phosphatase activity in Castanopsis carlesii and Cunninghamia lanceolata forest soils developed from two types of parent materials, sandstone and granite, in Sanming, Fujian Province. The results showed that both parent material and forest type significantly affected the contents of different P fractions. The contents of total P, labile inorganic/organic P, moderately labile inorganic/organic P, and non-labile P from sandstone-developed soils were significantly higher than those from granite-developed soils. Moreover, soil labile organic P, moderately labile inorganic/organic P and non-labile P fraction in sandstone-developed soils of C. carlesii forest were significantly higher than those of C. lanceolata forest, while the corresponding soil P fractions in granite-deve-loped soils had no significant difference between the two types of forests. The activity of acid phosphatase (ACP) in granite-developed soils was significantly higher than that in sandstone-developed soils under two types of forest, while soil microbial biomass carbon (MBC) and P (MBP) in sandstone-developed soils were significantly higher under C. carlesii forest than under C. lanceolata fo-rest. The content of soil P fractions was significantly positively correlated with the content of different forms of iron and aluminum oxides, MBP, and MBC, but negatively correlated with soil pH and acid phosphatase activity (ACP). Our results indicated that parent material and forest types might affect soil P fractions and characteristics mainly through altering soil iron and aluminum oxides, ACP, MBP in mid-subtropical forest soils.


Assuntos
Fósforo , Solo , Carbono/análise , China , Florestas , Nitrogênio/análise , Fósforo/análise
8.
Aging (Albany NY) ; 13(18): 21903-21913, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-34551393

RESUMO

The mortality rate of young female COVID-19 patients is reported to be lower than that of young males but no significant difference in mortality was found between female and male COVID-19 patients aged over 65 years, and the underlying mechanism is unknown. We retrospectively analyzed clinical characteristics and outcomes of severely ill pre- and post-menopausal COVID-19 patients and compared with age-matched males. Of the 459 patients included, 141 aged ≤55, among whom 19 died (16 males vs. 3 females, p<0.005). While for patients >55 years (n=318), 115 died (47 females vs. 68 males, p=0.149). In patients ≤55 years old, the levels of NLR, median LDH, median c-reactive protein and procalcitonin were significantly higher while the median lymphocyte count and LCR were lower in male than in female (all p<0.0001). In patients over 55, these biochemical parameters were far away from related normal/reference values in the vast majority of these patients in both genders which were in contrast to that seen in the young group. It is concluded that the mortality of severely ill pre-menopausal but not post-menopausal COVID-19 female patients is lower than age-matched male. Our findings support the notion that estrogen plays a beneficial role in combating COVID-19.


Assuntos
COVID-19/mortalidade , Estrogênios/metabolismo , Menopausa , Índice de Gravidade de Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteína C-Reativa/metabolismo , COVID-19/metabolismo , Feminino , Identidade de Gênero , Humanos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Neutrófilos/metabolismo , Pós-Menopausa , Pré-Menopausa , Pró-Calcitonina/sangue , Estudos Retrospectivos , SARS-CoV-2 , Fatores Sexuais
9.
Mol Med Rep ; 23(1)2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33179101

RESUMO

Huangqi, the dried root of Radix Astragali, is an essential herb in Traditional Chinese Medicine and has been used to promote hematopoiesis for centuries. Astragalus polysaccharide (ASPS), the bioactive compound of Huangqi, serves a crucial role in hematopoiesis. The aim of the present study was to investigate the hematopoietic effects, in particular the thrombopoietic effects, and the molecular mechanisms of ASPS using an irradiation­induced myelosuppressive mouse model. Colony­forming unit assays, flow cytometric analysis of apoptosis, ELISAs, Giemsa staining and western blotting were performed to determine the hematopoietic and anti­apoptotic effects of ASPS. The results demonstrated that ASPS enhanced the recovery of red blood cells at day 21 following treatment, as well as platelets and white blood cells at day 14. In addition, ASPS promoted colony formation in all lineages (megakaryocytes, granulocyte monocytes, erythroid cells and fibroblasts). The morphological study of the bone marrow demonstrated that tri­lineage hematopoiesis was preserved in the ASPS­ and thrombopoietin (TPO)­treated groups compared with the control group. The overall cellularity (mean total cell count/area) of the ASPS­treated group was similar to that of the TPO­treated group. Additionally, in vitro experiments indicated that treatment with 100 µg/ml ASPS exhibited the maximum effect on colony formation. ASPS attenuated cell apoptosis in megakaryocytic cells via inhibiting the mitochondrial caspase­3 signaling pathway. In conclusion, ASPS promoted hematopoiesis in irradiated myelosuppressive mice possibly via enhancing hematopoietic stem/progenitor cell proliferation and inhibiting megakaryocytes apoptosis.


Assuntos
Medicamentos de Ervas Chinesas/química , Megacariócitos/citologia , Polissacarídeos/administração & dosagem , Lesões Experimentais por Radiação/tratamento farmacológico , Trombocitopenia/prevenção & controle , Animais , Apoptose/efeitos dos fármacos , Astragalus propinquus , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Hematopoese/efeitos dos fármacos , Hematopoese/efeitos da radiação , Injeções Intraperitoneais , Masculino , Megacariócitos/efeitos dos fármacos , Megacariócitos/efeitos da radiação , Camundongos , Polissacarídeos/farmacologia , Lesões Experimentais por Radiação/complicações , Lesões Experimentais por Radiação/metabolismo , Trombocitopenia/etiologia
10.
J Environ Qual ; 49(2): 335-345, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016435

RESUMO

Biochar is composed of carbonaceous and inorganic (ash) fractions. The structural properties of carbonaceous fractions and the composition of ash in biochar are both variable with pyrolysis temperature. However, it is unknown whether ash may play different roles in sorption of organic compounds to the carbonaceous fraction of biochars produced at different temperatures. Hence, in this study, the pristine biochars produced at 300-900°C and their corresponding deashed biochars were investigated, and the combined roles of carbonaceous fraction and ash in sorption of triclosan were compared. The results showed that the biochars produced at 300-400°C had high content of uncarbonized organic structure with dominating partition effect. The combination of uncarbonized organic structure and ash had comparable or even higher sorption coefficient (KD ) for triclosan at low concentration compared with a single uncarbonized organic structure. However, for the biochars produced at 600-900°C, which were mainly composed of carbonized or graphitized carbon structure, ash had significant effect on triclosan sorption by reducing surface adsorption and pore filling effect. The combination of carbonaceous fraction and ash decreased KD values for triclosan at any tested concentrations. In addition, the results of pH effect on sorption indicated that ash possibly decreased the electrostatic repulsion of deprotonated phenolic hydroxyl between biochars and triclosan. Accordingly, it will be more valuable to design biochars for pollutant sorption from the perspective of combined role of carbonaceous fraction and ash rather than a single role of carbonaceous fraction.


Assuntos
Triclosan , Madeira , Carvão Vegetal , Temperatura
11.
J Environ Qual ; 49(5): 1396-1407, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33016453

RESUMO

The different effects of nitrogen-flow (NF) and air-limitation (AL) pyrolysis on the characteristics and nutrient retention of biochars (BCs) are unclear. Hence, in this study, BCs derived from bamboo, corn straw, and wheat straw were produced in AL and NF atmospheres at various temperatures (300-750 °C), and their different characteristics and nutrient retention rates were compared systematically. Nitrogen-flow pyrolysis facilitates C retention and graphitic C formation, and AL pyrolysis improves the polarity and supports the formation of oxygen-containing groups. With increasing pyrolysis temperature, C retention and graphitic C formation in BCs derived from AL pyrolysis decreases more significantly compared with BCs from NF pyrolysis. At 750 °C, the polarity and oxygen-containing groups of BCs derived from AL pyrolysis increase, whereas those from BCs derived from NF pyrolysis decrease. The observations are attributable to the AL and high-temperature-enhanced oxidization and gasification of C. An AL atmosphere with a higher pyrolysis temperature supports porosity and results in a larger specific surface area. Although pyrolysis temperature and atmosphere have negligible effects on nutrient retention, a low pyrolysis temperature facilitates the formation of water-soluble Ca, Mg, and P, and AL pyrolysis facilitates the formation of water-soluble P because the high pyrolysis temperature improves the pH and mineral stability of BCs, and air limitation facilitates the oxidation of organic P into PO4 3- . This study provides a reference for selecting AL or NF pyrolysis based on various pyrolysis temperatures to produce BCs and applying these in C sequestration, contaminant sorption, and soil quantity improvement.


Assuntos
Carvão Vegetal , Nitrogênio , Nutrientes , Temperatura
12.
Sci Total Environ ; 749: 141583, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-32814205

RESUMO

There has been an increasing interest in studying microbial necromasses and their contribution to soil organic carbon (SOC) accumulation. However, it remains unclear how the interaction among climate, plants, and soil influence the microbial anabolism and how microbial necromass contribute to SOC formation. Here, we assessed the relative contribution of microbial residues to SOC pool across a subtropical elevation gradient (ranged from 630 to 2130 m a.s.l.) representing a subtropical ecosystem on Wuyi Mountain in China, by using amino sugars as tracers. Analysis of topsoil (0-10 cm) amino sugars and the composition of microbial community across this gradient revealed that the soil total amino sugars accounting for 12.2-25.7% of the SOC pool, decreased with increasing elevation. Moreover, the linear reduction in the bacterial-derived carbon (C) and an increase in the ratio of fungal- to bacterial-derived C with increasing elevation suggested the reduction in the contribution of bacterial-derived C to SOC pool across this elevation gradient. The divergent changes in the contribution of the microbial residues to SOC infer a potential change in SOC composition and stability. The microbial-derived SOC formation and its climatic responses are influenced by the interaction of vegetation types and soil properties, with soil amorphous Fe being the determiner of soil amino sugar accrual. Our work highlights the importance of understanding ecosystem type and mineral composition in regulating microbial-mediated SOC formation and accumulation in responses to climate change in subtropical ecosystems.


Assuntos
Carbono , Solo , Carbono/análise , China , Ecossistema , Microbiologia do Solo
13.
Huan Jing Ke Xue ; 41(4): 1847-1854, 2020 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608693

RESUMO

The contents and sources of 15 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were analyzed in 59 surface soil samples (0-10 cm depth) collected from six functional zones, including cultural and educational area, park, residential area, vegetable garden, gas station, and industrial area, in Yangzhou City. The toxicity equivalent content of benzo[a]pyrene (TEQBaP) was adopted to assess PAH risks in soils. The results showed that the contents of Σ15PAHs in soil samples ranged from 21 to 36118 µg·kg-1, with a median value of 295 µg·kg-1. The composition of PAHs was dominated by 4-6 ring PAHs. The average contents of Σ15PAHs in various functional zones in Yangzhou City was in the order of industrial area > gas station > cultural and educational area > vegetable garden > residential area > park. Correlation analysis showed that the contents of Σ15PAHs were significantly positively correlated with the contents of both TOC (P<0.05) and BC (P<0.01) in soil samples from whole Yangzhou City. However, the contents of Σ15PAHs had no significant correlations with the contents of both TOC and BC in soil samples within each functional zone except gas station, in which the contents of Σ15PAHs had a significant correlation with those of BC (P<0.01). The results of PAH ratios showed that the sources of PAHs in soils of various functional zones were mainly from oil leakage and the combustion of oil, coal, and biomass, although there were some differences among them. The values of ΣTEQBaP of 15 PAHs ranged from 2 to 4448 µg·kg-1 in the soil samples of Yangzhou City. According to the standard value of 33 µg·kg-1 of ΣTEQBaP for 10 PAHs in the soil environmental standard of Netherland, 45.8% of soil samples exceeded the standard in Yangzhou City. The percentages of soil samples exceeding the standard of various functional zones in Yangzhou City were in the order of industrial area (70%) > gas station (60%) > cultural and educational area (55.6%) > vegetable garden (50.0%) > residential area (30%) > park (10%). Hence, in all the functional zones of Yangzhou City, there were some soil samples with potential ecological risks, which was relatively higher in industrial area and gas station, and relatively lower in residential area and park.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , China , Cidades , Monitoramento Ambiental , Medição de Risco , Solo
14.
Sci Total Environ ; 742: 140416, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32721714

RESUMO

A crucial mechanism for the application of biochar in soil improvement is the direct release of nutrients from biochar. Low molecular weight organic acids (LMWOAs) ubiquitously exist in soil. However, the mechanism of LMWOAs-mediated release of nutrients from biochars remains little known. Ten biochars with different mineral element stoichiometric ratio were produced, and four LMWOAs [acetic (HAc), glycolic (GA), tartaric (TA), and citric acids (CA)] were employed, to enunciate the influence mechanism of LMWOAs on the release of phosphorus and potassium from biochar. The results showed that HAc suppressed the release of P from biochars, while TA and CA facilitated the release of P from biochars with high ratios of polyvalent metals to P. A new mechanism was proposed that the deprotonated HAc combined with the dissolved HPO42- or H2PO4- to form a complex through hydrogen bond and cation bridging. The hydrophobic methyl group of HAc was exposed outside of the complex, which decreased the water-solubility of phosphate. Meanwhile, a high ratio of polyvalent metals to P benefited more P to combine with polyvalent metals, which decreased the water-solubility of P, but the deprotonated TA and CA are polyvalent anions that could substitute this part of P by anion exchange. Also, LMWOAs promoted the release of K from biochars with low K/(P + S) ratios, possibly due to unionized carboxyl of LMWOAs served as a hydrogen bond donor to displace K out of biochars. This study gives a deep understanding of the fate of biochar originated nutrients response to LMWOAs.


Assuntos
Fósforo , Poluentes do Solo/análise , Carvão Vegetal , Minerais , Peso Molecular , Potássio , Solo
15.
Aging (Albany NY) ; 12(13): 13633-13646, 2020 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32651992

RESUMO

Clinical studies have shown that melatonin lowers the frequency of thrombocytopenia in patients with cancer undergoing radiotherapy or chemotherapy. Here, we investigated the mechanisms by which melatonin promotes platelet formation and survival. Our results show that melatonin exerted protective effects on serum-free induced apoptosis of CHRF megakaryocytes (MKs). Melatonin promoted the formation of MK colony forming units (CFUs) in a dose-dependent manner. Using doxorubicin-treated CHRF cells, we found that melatonin rescued G2/M cell cycle arrest and cell apoptosis induced by doxorubicin. The expression of p-AKT was increased by melatonin treatment, an effect that was abolished by melatonin receptor blocker. In addition, we demonstrated that melatonin enhanced the recovery of platelets in an irradiated mouse model. Megakaryopoiesis was largely preserved in melatonin-treated mice. We obtained the same results in vivo from bone marrow histology and CFU-MK formation assays. Melatonin may exert these protective effects by directly stimulating megakaryopoiesis and inhibiting megakaryocyte apoptosis through activation of its receptors and AKT signaling.


Assuntos
Megacariócitos/efeitos dos fármacos , Melatonina/farmacologia , Lesões Experimentais por Radiação/prevenção & controle , Trombocitopenia/prevenção & controle , Trombopoese/efeitos dos fármacos , Animais , Antineoplásicos/efeitos adversos , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Plaquetas/efeitos dos fármacos , Plaquetas/fisiologia , Plaquetas/efeitos da radiação , Medula Óssea/efeitos dos fármacos , Medula Óssea/fisiologia , Medula Óssea/efeitos da radiação , Caspases/metabolismo , Linhagem Celular Tumoral , Doxorrubicina/efeitos adversos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Humanos , Masculino , Megacariócitos/fisiologia , Melatonina/uso terapêutico , Camundongos , Mitocôndrias/metabolismo , Neoplasias/terapia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Lesões Experimentais por Radiação/sangue , Lesões Experimentais por Radiação/etiologia , Receptores de Melatonina/antagonistas & inibidores , Receptores de Melatonina/metabolismo , Células-Tronco/efeitos dos fármacos , Trombocitopenia/sangue , Trombocitopenia/etiologia , Trombopoese/efeitos da radiação , Irradiação Corporal Total
16.
Aging (Albany NY) ; 12(8): 7397-7410, 2020 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-32341206

RESUMO

Thrombopoietin (TPO) is a growth factor for the megakaryocytic/platelet lineage. In this study, we investigated the expression of TPO and its receptor, c-Mpl, in the human central nervous system (CNS) and their roles after a neural insult. Our results demonstrate that both TPO and c-Mpl are expressed in the neurons of the human CNS. TPO was also detected in human cerebrospinal fluid. TPO was found to be neuroprotective in hypoxic-ischemic neonatal rat brain models. In these rat models, treatment with TPO reduced brain damage and improved sensorimotor functions. In addition, TPO promoted C17.2 cell proliferation through activation of the PI3K/Akt signaling pathway. Via the Bcl-2/BAX signaling pathway, TPO exerted an antiapoptotic effect by suppressing mitochondrial membrane potentials. Taken together, our results indicate that TPO is neuroprotective in the CNS.


Assuntos
Sistema Nervoso Central/metabolismo , Regulação da Expressão Gênica , Neurônios/metabolismo , Receptores de Trombopoetina/genética , Trombopoetina/genética , Animais , Apoptose , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Sistema Nervoso Central/citologia , Humanos , Modelos Animais , Neurônios/citologia , Ratos , Receptores de Trombopoetina/biossíntese , Transdução de Sinais , Trombopoetina/biossíntese
17.
Phys Rev E ; 101(2-1): 023312, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32168627

RESUMO

The discrete unified gas kinetic scheme (DUGKS) with a force term is a finite volume solver for the Boltzmann equation. Unlike the standard lattice Boltzmann method (LBM), DUGKS can be applied on nonuniform grids. For both the LBM and DUGKS, the boundary conditions need to be processed through the density distribution function. So researchers introduced the boundary conditions from the LBM frame into the DUGKS. However, the accuracy of these boundary conditions in the DUGKS has not been studied thoroughly. Through strict theoretical deduction, we find that the bounce-back (BB) scheme leads to a different dependence of the numerical error term in the DUGKS as compared to the LBM. The error term is influenced by the relaxation time and the body force. And it can be reduced by lowering the kinetic viscosity. Unlike the BB scheme, the nonequilibrium bounce-back scheme has the ability to implement real no-slip boundary condition. Furthermore, two slip boundary conditions incorporated with Navier's slip model are introduced from the LBM framework into the DUGKS. The tangential momentum change-based (TMAC) scheme can be used directly in the DUGKS because it generates no numerical error term in the DUGKS. For the combination of the bounce-back and specular reflection schemes (BSR), the relation between the slip length and the combination parameter should be modified in accordance with the numerical error term. Analysis shows that the TMAC scheme can simulate a wider range of slip length than the BSR scheme. Numerical simulations of the Couette flow and the Poiseuille flow confirm our theoretical analysis.

18.
Chemosphere ; 250: 126283, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32120148

RESUMO

On 3rd to May 24, 2018, volatile organic compound (VOC) samples were collected four times a day by using stainless steel canisters at an urban site in Zhengzhou, China. The concentrations, compositions, sources, ozone (O3) formation potential (OFP), and health risk assessment of VOCs were discussed based on the measurements of 103 VOC species. Results show that the average mixing ratio of VOCs was 29.11 ± 15.33 ppbv, and the dominant components comprised oxygenated VOCs (OVOCs) and alkanes, followed by halocarbons, alkenes, aromatics, and a sulfide. Various groups of VOCs had typical diurnal variation characteristics. Alkenes, alkanes, and aromatics contributed most to the OFP. Five sources identified by the positive matrix factorization model revealed solvent utilization as the largest contributor, followed by industrial production, long-lived and secondary species, vehicular emission, and biogenic emission. Solvent utilization and vehicular emission were important sources to OFP. During O3 episode days, the mixing ratios of alkanes, alkenes, halocarbons, OVOCs, aromatics, and TVOCs decreased to varying degrees; the source contribution of solvent utilization decreased significantly while industrial production showed the opposite trend. VOC species and sources posed no non-carcinogenic risk while five species and all sources except for biogenic emission had carcinogenic risks to exposed population. Industrial emission was the largest contributor to both non-carcinogenic and carcinogenic risks. These results will help to provide some references for O3 pollution research and prevention and control of pollution sources.


Assuntos
Monitoramento Ambiental/métodos , Ozônio/toxicidade , Saúde da População Urbana/normas , Compostos Orgânicos Voláteis/análise , Poluentes Atmosféricos/análise , Alcanos/análise , China , Humanos , Ozônio/análise , Ozônio/química , Medição de Risco
19.
Huan Jing Ke Xue ; 40(6): 2565-2571, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854647

RESUMO

Based on the annual average concentration values, the health effects and health benefits as well as 95% confidence intervals of PM10 and PM2.5 pollution control from 2014 to 2016 in Zhengzhou were evaluated by applying the Poisson regression relative risk model. Results showed that the health benefits of PM10 pollution control were 18.18 billion RMB (15.04, 21.12), 24.25 billion RMB (20.25, 27.94), and 20.62 billion RMB (17.33, 23.92), which accounted for 2.7%, 3.3%, and 2.5% of the GDP of Zhengzhou, respectively, in 2014-2016. The health benefits of PM2.5 pollution control were 17.88 billion RMB (14.37, 21.16), 21.65 billion RMB (17.46, 25.53), and 17.25 billion RMB (13.78, 20.55), which accounted for 2.6%, 3.0%, and 2.1% of the GDP of Zhengzhou, respectively, in 2014-2016. After the PM10 and PM2.5 pollution was controlled, the number of urban beneficiaries was higher than that of rural areas, and acute bronchitis beneficiaries were higher than the beneficiaries of other health end-points. For chronic bronchitis, adults benefited more than children, while the opposite occurred for asthma. In this study, chronic bronchitis had the highest health benefit, followed by asthma, and outpatient and inpatient setting had the lower health benefits.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/prevenção & controle , Material Particulado/efeitos adversos , Adulto , Asma/prevenção & controle , Bronquite Crônica/prevenção & controle , Criança , China , Humanos , Análise de Regressão
20.
Huan Jing Ke Xue ; 40(7): 2977-2984, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854694

RESUMO

In order to explore the pollution characteristics of water-soluble ions in PM2.5 in Zhengzhou, high time resolution and continuous observation of water-soluble inorganic ions in PM2.5 was conducted from December 1, 2017, to November 30, 2018, in Zhengzhou. The results showed that during the observation period, the average concentration of total water-soluble ions in Zhengzhou was 42.7 µg·m-3. The order of mass concentration of each ion, from large to small, was as follows:NO3-(17.7 µg·m-3), SO42-(10.2 µg·m-3), NH4+(9.0 µg·m-3), Cl-(2.3 µg·m-3), K+(1.3 µg·m-3), Na+(1.3 µg·m-3), Ca2+(0.8 µg·m-3), and Mg2+(0.1 µg·m-3). The mass concentration of total water-soluble ions was the highest in winter, slightly higher in autumn than in spring, and lowest in summer. The diurnal variation in single peak distribution was observed across the whole year in spring, summer, and autumn, while there was no significant diurnal variation in winter. The mass concentration of secondary inorganic ions (SO42-, NO3-, and NH4+) accounted for 43.8% of PM2.5, mainly in the form of (NH4)2SO4 and NH4NO3. There was a large degree of secondary transformation throughout the observation period; relative humidity had a significant influence on the sulfur oxidation rate, and temperature had a significant influence on the nitrogen oxidation rate. During the observation period, there was a good correlation between secondary ions, and K+ showed a good correlation with Mg2+ and Cl-. The main source of the secondary ions was the secondary conversion of gaseous pollutants. Mg2+ and Ca2+ were derived from soil dust and construction dust. K+ was one of the main biomarkers of biomass combustion. Na+ was mainly derived from sea salt and soil dust, and Cl- was derived not only from sea salt but also biomass and fossil fuel combustion. The results of principal component analysis showed that the water-soluble ions in PM2.5 in Zhengzhou were mainly affected by secondary transformation, combustion sources, and dust emission from soil or building construction.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...