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1.
Environ Pollut ; 263(Pt B): 114507, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283398

RESUMO

The accurate derivation of the proportion and absorption enhancement of black carbon (BC)-containing aerosols in the atmosphere is critical to assess their effect on air quality and climate. Here, using the field measured size-resolved volatility shrink factor, BC bulk mass concentration and the BC mass fraction in BC-containing particles in winter Beijing, we retrieved and quantified both the number and mass concentration of (1) non-BC, (2) internally mixed BC and (3) externally mixed BC of ambient fine aerosol particles. The reliability of the retrieval method has been evaluated by comparing with the simultaneously measured data. The number fraction of BC-containing particles accounts for 60-78% of ambient fine particles, with internally (both BC core and coating materials) and externally mixed BC of 51-64% and 9-23%, respectively. Only for nucleated particles on clean days, when nucleation is a major source of aerosol particles, did the non-BC component dominate (54%). A large amount of aerosols are BC-containing particles, with mass fraction of 32-52%, suggesting the dominant role of BC in elevating mass concentration of particulate matter (PM) in a polluted urban area. We also show that the BC particles are thickly coated with coating thickness (characterized by Dp/Dc, ratio of the BC diameter before and after heating at 300 °C) of 1.6-2.2, implying efficient aging of BC particles in polluted urban area. Our results imply a large proportion of BC-containing particles in the atmosphere, which could help towards understanding the role of BC on regional haze formation and climate forcing.

2.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 33(12): 1486-1490, 2019 Dec 15.
Artigo em Chinês | MEDLINE | ID: mdl-31823545

RESUMO

Objective: To investigate the safety and effectiveness of pedicle screw implantation via vertebral arch-transverse pathway in clinical application by a prospective randomized controlled trial. Methods: Twenty-four patients who were admitted between May 2015 and June 2017 and met the selection criteria for thoracic pedicle screw fixation were included in the study. According to the random number table method, they were divided into the trial group (screw implantation via vertebral arch-transverse pathway) and the control group (traditional screw implantation technology), with 12 patients in each group. There was no significant difference between the two groups in age, gender, cause of injury, injured segment, and the interval between injury and operation (P>0.05). The time of screw implantation was recorded and compared between the two groups. The acceptable rate of screw implantation and the penetration rate of pedicle wall were calculated after operation. Results: The time of screw implantation of trial group was (5.08±1.74) minutes, which was significantly shorter than that of control group [(5.92±1.66) minutes], and the difference was significant (t=4.258, P=0.023). Patients in both groups were followed up 1-2 years, with an average of 1.5 years. During the follow-up, no failure of internal fixation occurred. At 1 week after operation, the screw implantation in trial group was rated as gradeⅠin 54 screws, gradeⅡ in 3 screws, and grade Ⅲ in 2 screws, with the acceptable rate of 93.61%. The screw implantation in control group was rated as gradeⅠin 40 screws, grade Ⅱin 10 screws, grade Ⅲ in 8 screws, and grade Ⅳ in 1 screw, with the acceptable rate of 84.75%. There was significant difference in the acceptable rate of screw implantation between the two groups (χ2=3.875, P=0.037). The penetration rate of pedicle wall in trial group was 8.47% (5/59), which was significantly lower than that in the control group [32.20% (19/59); χ2=4.125, P=0.021]. Conclusion: Compared with the traditional technique, the pedicle screw implantation via vertebral arch-transverse pathway can obtain a good position of the screw canal with higher accuracy and simpler operation.


Assuntos
Parafusos Pediculares , Fraturas da Coluna Vertebral , Fixação Interna de Fraturas , Humanos , Vértebras Lombares , Estudos Prospectivos , Fraturas da Coluna Vertebral/cirurgia , Vértebras Torácicas , Resultado do Tratamento
3.
Environ Sci Technol ; 53(22): 13265-13274, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31607119

RESUMO

Particulate matter with aerodynamic diameters ≤1 µm (PM1) has a greater impact on the human health but has been less studied due to fewer ground observations. This study attempts to improve the retrieval accuracy and spatial resolution of satellite-based PM1 estimates using the new ground-based monitoring network in China. Therefore, a space-time extremely randomized trees (STET) model is first developed to estimate PM1 concentrations at a 1 km spatial resolution from 2014 to 2018 across mainland China. The STET model can derive daily PM1 concentrations with an average across-validation coefficient of determination of 0.77, a low root-mean-square error of 14.6 µg/m3, and a mean absolute error of 8.9 µg/m3. PM1 concentrations are generally low in most areas of China, except for the North China Plain and Sichuan Basin where intense human activities and poor natural conditions are prevalent, especially in winter. Moreover, PM1 pollution has greatly decreased over the past 5 years, benefiting from emission control in China. The STET model, incorporating the spatiotemporal information, shows superior performance in PM1 estimates relative to previous studies. This high-resolution and high-quality PM1 data set in China (i.e., ChinaHighPM1) can be greatly useful for air pollution studies in medium- or small-scale areas.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , China , Monitoramento Ambiental , Humanos , Material Particulado
4.
Artif Intell Med ; 99: 101694, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31606108

RESUMO

Diabetic retinopathy (DR) is the most common cause of blindness in middle-age subjects and low DR screening rates demonstrates the need for an automated image assessment system, which can benefit from the development of deep learning techniques. Therefore, the effective classification performance is significant in favor of the referable DR identification task. In this paper, we propose a new strategy, which applies multiple weighted paths into convolutional neural network, called the WP-CNN, motivated by the ensemble learning. In WP-CNN, multiple path weight coefficients are optimized by back propagation, and the output features are averaged for redundancy reduction and fast convergence. The experiment results show that with the efficient training convergence rate WP-CNN achieves an accuracy of 94.23% with sensitivity of 90.94%, specificity of 95.74%, an area under the receiver operating curve of 0.9823 and F1-score of 0.9087. By taking full advantage of the multipath mechanism, the proposed WP-CNN is shown to be accurate and effective for referable DR identification compared to the state-of-art algorithms.

5.
Sci Total Environ ; 692: 879-891, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539993

RESUMO

The next-generation geostationary meteorological Himawari-8 satellite carrying the Advanced Himawari Imager (AHI) allows frequent observations of the atmosphere, the surface, and oceans every 10 min. With its retrieval algorithms recently updated, Himawari-8/AHI Version 2 Level 2 aerosol products are now available. However, these retrievals have not yet undergone a quality assessment. This study aims to comprehensively validate the official aerosol optical properties derived from Himawari-8/AHI over land and ocean. Aerosol Robotic Network and Sun-Sky Radiometer Observation Network ground-based measurements at 98 stations in the Himawari-domain region are used to validate aerosol optical depth (AOD, or τ) retrievals at 500 nm and Ångström exponent (AE) retrievals at 440-675 nm from the year 2016. The AOD retrievals agree well with surface observations (i.e., from linear regression, slope = 0.876, intercept = 0.076, and correlation coefficient = 0.756) with a mean absolute error and a root-mean-square error of 0.168 and 0.293, respectively. On site and regional scales, large uncertainties are seen, especially in Australia (significant overestimation) and South Asia (significant underestimation). The AOD retrievals can correctly capture daily variations and show the best (worst) performance in summer (spring). The AE performance is poorer on all scales, showing overall underestimations, especially in Australia, Southeast Asia, and China. The data quality of AOD retrievals improves as the vegetation coverage and the AE increases. This suggests that the official aerosol retrieval algorithm still faces great challenges over bright surfaces and under coarse-particle-dominated conditions. In general, approximately 61% and 64% of the AOD matchups meet the newly defined expected errors of [0.330 × τ + 0.024; -0.132 × τ - 0.125] and [0.519 × τ + 0.005; -0.007 × τ - 0.194] determined by ground measurements and aerosol retrievals, respectively. The highly variable accuracy of aerosol retrievals raises a concern about the reliability of the current product under different environmental conditions and underlying surfaces. It also sheds light on what future improvements need implementing to the aerosol retrieval algorithm.

6.
Sci Total Environ ; 683: 389-398, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31136965

RESUMO

The importance of fungi as cloud condensation nuclei (CCN) and ice-forming nuclei (IN) has been recognized for some researches. Particle growth along with new particle formation (NPF) play a joint role in modulating the CCN number concentration. Although fungi can accelerate the coalescence by large particles, the specific contribution and characteristics of atmospheric fungi for particle growth, especially during NPF events, is poorly understood. In this study, aerosol size distribution data and air samples were collected at Xingtai, a suburban site in the central North China Plain, from 1 May to 1 June 2016. Using DNA sequence-based methods, atmospheric fungal communities were identified and quantified. Significant differences in fungal communities between particle growth events along with new particle formation (PGE-NPF) and non-PGE-NPF events are found, especially for the Ascomycota and Basidiomycota phyla, and the Dothideomycetes, Saccharomycetes, and Tremellomycetes classes. At the genus level, five fungal communities were significantly different under PGE-NPF and non-PGE-NPF conditions, i.e., the Cladosporium, Capnodiales, Mrakia, Saccharomycetales and Trichocomaceae genera. The air mass source not only had an impact on NPF and the particle growth process, but also on the characteristics of the fungal communities. The fungal genus communities of Cladosporium, Capnodiales, Trichocomaceae, Mrakia, and Saccharomycetales may contribute to NPF and the particle growth process.


Assuntos
Aerossóis/análise , Microbiologia do Ar , Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental , Fungos/crescimento & desenvolvimento , China , Material Particulado/análise
7.
BMC Genomics ; 20(1): 215, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30866797

RESUMO

BACKGROUND: Massively-parallel-sequencing, coupled with sample multiplexing, has made genetic tests broadly affordable. However, intractable index mis-assignments (commonly exceeds 1%) were repeatedly reported on some widely used sequencing platforms. RESULTS: Here, we investigated this quality issue on BGI sequencers using three library preparation methods: whole genome sequencing (WGS) with PCR, PCR-free WGS, and two-step targeted PCR. BGI's sequencers utilize a unique DNA nanoball (DNB) technology which uses rolling circle replication for DNA-nanoball preparation; this linear amplification is PCR free and can avoid error accumulation. We demonstrated that single index mis-assignment from free indexed oligos occurs at a rate of one in 36 million reads, suggesting virtually no index hopping during DNB creation and arraying. Furthermore, the DNB-based NGS libraries have achieved an unprecedentedly low sample-to-sample mis-assignment rate of 0.0001 to 0.0004% under recommended procedures. CONCLUSIONS: Single indexing with DNB technology provides a simple but effective method for sensitive genetic assays with large sample numbers.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Bactérias/genética , Humanos , Sequenciamento Completo do Genoma , Fluxo de Trabalho
8.
Sci Rep ; 8(1): 8892, 2018 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-29875416

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

9.
Sci Rep ; 8(1): 3960, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29500395

RESUMO

Using NASA MERRA2 daily data, we investigated the origin, maintenance and variability of the Asian Tropopause Aerosol Layer (ATAL) in relation to variations of the Asia Monsoon Anticyclone (AMA) during the summer of 2008. During May-June, abundant quantities of carbon monoxide (CO), carbonaceous aerosols (CA) and dusts are found in the mid- and upper troposphere over India and China, arising from enhanced biomass burning emissions, as well as westerly transport from the Middle East deserts. During July-August, large quantities of dusts transported from the deserts are trapped and accumulate over the southern and eastern foothills of the Tibetan Plateau. Despite strong precipitation washout, ambient CO, CA and dust are lofted by orographically forced deep convection to great elevations, 12-16 km above sea level, via two key pathways over heavily polluted regions: a) the Himalayas-Gangetic Plain, and b) the Sichuan Basin. Upon entering the upper-troposphere-lower-stratosphere, the pollutants are capped by a stable layer near the tropopause, advected and dispersed by the anticyclonic circulation of AMA, forming the ATAL resembling a planetary-scale "double-stem chimney cloud". The development and variability of the ATAL are strongly linked to the seasonal march and intraseasonal (20-30 days and higher frequency) oscillations of the Asian monsoon.

10.
Science ; 359(6374): 411-418, 2018 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-29371462

RESUMO

Aerosol-cloud interactions remain the largest uncertainty in climate projections. Ultrafine aerosol particles smaller than 50 nanometers (UAP<50) can be abundant in the troposphere but are conventionally considered too small to affect cloud formation. Observational evidence and numerical simulations of deep convective clouds (DCCs) over the Amazon show that DCCs forming in a low-aerosol environment can develop very large vapor supersaturation because fast droplet coalescence reduces integrated droplet surface area and subsequent condensation. UAP<50 from pollution plumes that are ingested into such clouds can be activated to form additional cloud droplets on which excess supersaturation condenses and forms additional cloud water and latent heating, thus intensifying convective strength. This mechanism suggests a strong anthropogenic invigoration of DCCs in previously pristine regions of the world.

11.
Sci Rep ; 7(1): 14304, 2017 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-29123116

RESUMO

Severe haze is a major public health concern in China and India. Both countries rely heavily on coal for energy, and sulfur dioxide (SO2) emitted from coal-fired power plants and industry is a major pollutant contributing to their air quality problems. Timely, accurate information on SO2 sources is a required input to air quality models for pollution prediction and mitigation. However, such information has been difficult to obtain for these two countries, as fast-paced changes in economy and environmental regulations have often led to unforeseen emission changes. Here we use satellite observations to show that China and India are on opposite trajectories for sulfurous pollution. Since 2007, emissions in China have declined by 75% while those in India have increased by 50%. With these changes, India is now surpassing China as the world's largest emitter of anthropogenic SO2. This finding, not predicted by emission scenarios, suggests effective SO2 control in China and lack thereof in India. Despite this, haze remains severe in China, indicating the importance of reducing emissions of other pollutants. In India, ~33 million people now live in areas with substantial SO2 pollution. Continued growth in emissions will adversely affect more people and further exacerbate morbidity and mortality.

12.
Sci Rep ; 6: 36940, 2016 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-27833145

RESUMO

The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or "brown" carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths. Using the ground-based inversion of column effective imaginary refractive index in the range 305-368 nm, we quantified a strong spectral dependence of absorption by BrC in the UV and diminished ultraviolet B (UV-B) radiation reaching the surface. Reduced UV-B means less erythema, plant damage, and slower photolysis rates. We use a photochemical box model to show that relative to black carbon (BC) alone, the combined optical properties of BrC and BC slow the net rate of production of ozone by up to 18% and lead to reduced concentrations of radicals OH, HO2, and RO2 by up to 17%, 15%, and 14%, respectively. The optical properties of BrC aerosol change in subtle ways the generally adverse effects of smoke from biomass burning.

13.
Proc Natl Acad Sci U S A ; 113(21): 5828-34, 2016 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-26944081

RESUMO

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25° restricts the satellite coverage to ∼25% of the world area in a single day.

14.
J Environ Sci (China) ; 34: 44-56, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-26257345

RESUMO

Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (σsc), absorption coefficients (σab), Angström exponent (α), single scattering albedo (ω), backscattering ratio (ßsc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc(')) were obtained. The mean statistical values of σsc were 77.45 Mm(-1) (at 450 nm), 50.72 Mm(-1) (at 550n m), and 32.02 Mm(-1) (at 700 nm). The mean value of σab was 7.62 Mm(-1) (at 550 nm). The mean values of α, ßsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 µm. The vertical profiles of σsc,, α, ßsc, Qsc and Qsc(') showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and ßsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, ßsc, Qsc, Qsc('), σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Aeronaves , Altitude , China , Monitoramento Ambiental
15.
Proc Natl Acad Sci U S A ; 110(48): E4581-90, 2013 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-24218569

RESUMO

Deep convective clouds (DCCs) play a crucial role in the general circulation, energy, and hydrological cycle of our climate system. Aerosol particles can influence DCCs by altering cloud properties, precipitation regimes, and radiation balance. Previous studies reported both invigoration and suppression of DCCs by aerosols, but few were concerned with the whole life cycle of DCC. By conducting multiple monthlong cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macrophysical and microphysical properties of summer convective clouds and precipitation in the tropics and midlatitudes, this study provides a comprehensive view of how aerosols affect cloud cover, cloud top height, and radiative forcing. We found that although the widely accepted theory of DCC invigoration due to aerosol's thermodynamic effect (additional latent heat release from freezing of greater amount of cloud water) may work during the growing stage, it is microphysical effect influenced by aerosols that drives the dramatic increase in cloud cover, cloud top height, and cloud thickness at the mature and dissipation stages by inducing larger amounts of smaller but longer-lasting ice particles in the stratiform/anvils of DCCs, even when thermodynamic invigoration of convection is absent. The thermodynamic invigoration effect contributes up to ~27% of total increase in cloud cover. The overall aerosol indirect effect is an atmospheric radiative warming (3-5 W m(-2)) and a surface cooling (-5 to -8 W m(-2)). The modeling findings are confirmed by the analyses of ample measurements made at three sites of distinctly different environments.


Assuntos
Aerossóis/química , Movimentos do Ar , Atmosfera/química , Convecção , Modelos Teóricos , Vapor/análise , Simulação por Computador , Termodinâmica
16.
Ann Transplant ; 18: 558-66, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24126483

RESUMO

BACKGROUND: Oxidative stress is a major factor in the development of ischemia reperfusion injury (IRI) after heart transplantation. The isothiocyanate found in broccoli - sulforaphane (SFN) - is an indirect antioxidant that acts by inducing Nrf2-dependent Phase 2 enzymes, such as NAD(P)H-quinone oxidoreductase 1, glutathione reductase, glutathione peroxidase, and the cardioprotective enzymes, haemoxygenase-1 (HO-1) and thioredoxin (Trx-1), participate in adaptive and protective responses to oxidative stress and various inflammatory stimuli. The aim of this study was to ameliorate IRI following heart transplants by recipient preconditioning. MATERIAL AND METHODS: Male Lewis rats were randomly divided into groups of n=10 animals each for heart donation. Heart grafts underwent 18 hours of cold storage in histidine-tryptophanketoglutarate (HTK) solution. Preconditioning of recipients with sulforaphane was performed 24 hours before transplantation. RESULTS: SFN significantly decreased serum levels of TnT, CK, CK-MB, LDH, AST, and ALT, which correlated with better graft function scores and improved survival prognosis. Pretreated recipients showed significantly decreased expression of iNOS, caspase 3, and HIF-1a. CONCLUSIONS: Our results indicate that recipient preconditioning with SFN protects the heart from IRI after experimental transplantation.


Assuntos
Transplante de Coração/métodos , Coração/efeitos dos fármacos , Isotiocianatos/farmacologia , Miocárdio/patologia , Traumatismo por Reperfusão/prevenção & controle , Animais , Isotiocianatos/uso terapêutico , Masculino , Ratos , Ratos Endogâmicos Lew , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/patologia
17.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 27(10): 1234-9, 2013 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-24397138

RESUMO

OBJECTIVE: To investigate the effect of N-acetylcysteine (NAC) on the apoptosis during myocardial ischemia reperfusion injury in rats' heart transplantation, and to explore the possible role of NAC in myocardial apoptosis. METHODS: Sixty healthy male Lewis rats (weighing, 200-220 g) were randomly divided into 3 groups, 20 rats each group (10 donors and 10 recipients). In control group, 1 mL normal saline was infused via inferior vena cava at 30 minutes before donor harvesting; in donor preconditioning group, NAC (300 mg/kg) was infused via inferior vena cava at 30 minutes before donor harvesting, but no treatment in recipients; and in recipient preconditioning group, NAC (300 mg/kg) was infused via inferior vena cava at 30 minutes before recipient transplantation, but no treatment in donors. Heart transplantation was established in each group. Blood was drawn at 6 and 24 hours after reperfusion for analysis of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) as markers of graft injury; myocardial tissue was harvested to determine the superoxide dismutase (SOD) and lipid hydroperoxide (LPO) activity at 24 hours after reperfusion and to observe the histology and ultrastructural changes. Graft active Caspase-3 protein expression was measured by immunohistochemistry staining, and apoptosis index (AI) was calculated by TUNEL. RESULTS: The heart transplantation operation was successfully completed in all groups, and the rats survived to the end of the experiment. The serum levels of AST, ALT, and LDH in donor and recipient preconditioning groups were significantly lower than those in control group at 6 hours after reperfusion (P < 0.05); the levels of AST and ALT in donor preconditioning group and the levels of AST and LDH in recipient preconditioning group were significantly lower than those in control group at 24 hours (P < 0.05); and no significant difference was found between donor and recipient perconditioning groups (P > 0.05). The levels of AST, ALT, and LDH at 24 hours were significantly lower than those at 6 hours in each group (P < 0.05) except the level of ALT in recipient preconditioning group (P > 0.05). SOD activity and SOD/LPO in donor and recipient preconditioning groups were significantly higher than those in control group (P < 0.05), but no significant difference between donor and recipient preconditioning groups (P > 0.05); there was no significant difference in LPO activity among 3 groups (P > 0.05). Histological staining and transmission electron microscope showed that myocardial injury in recipient preconditioning group was obviously lighter than that in donor preconditioning group and control group. Active Caspase-3 in recipient pretreatment group was significantly higher than that in donor preconditioning group and control group (P < 0.05). AI of donor and recipient preconditioning groups was significantly lower than that of control group (P < 0.05), but no significant difference was found between donor and recipient preconditioning groups (P > 0.05). CONCLUSION: NAC can relieve ischemia reperfusion injury in rats' heart transplantation by improving myocardial SOD content, and reducing active Caspase-3 activity and AI, which has a protective effect on myocardial cell of donor heart.


Assuntos
Acetilcisteína/farmacologia , Apoptose/efeitos dos fármacos , Transplante de Coração/métodos , Precondicionamento Isquêmico/métodos , Substâncias Protetoras/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Acetilcisteína/administração & dosagem , Animais , Caspase 3/metabolismo , Modelos Animais de Doenças , Sobrevivência de Enxerto , Transplante de Coração/efeitos adversos , Imuno-Histoquímica , Injeções Intravenosas , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Distribuição Aleatória , Ratos , Ratos Endogâmicos Lew , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/patologia , Superóxido Dismutase/metabolismo
18.
HPB Surg ; 2012: 783479, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22791934

RESUMO

Background. Several approaches have been proposed to pharmacologically ameliorate hepatic ischemia/reperfusion injury (IRI). This study was designed to evaluate the effects of a preconditioning oral nutritional supplement (pONS) containing glutamine, antioxidants, and green tea extract on hepatic warm IRI in pigs. Methods. pONS (70 g per serving, Fresenius Kabi, Germany) was dissolved in 250 mL tap water and given to pigs 24, 12, and 2 hrs before warm ischemia of the liver. A fourth dose was given 3 hrs after reperfusion. Controls were given the same amount of cellulose with the same volume of water. Two hours after the third dose of pONS, both the portal vein and the hepatic artery were clamped for 40 min. 0.5, 3, 6, and 8 hrs after reperfusion, heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), portal venous flow (PVF), hepatic arterial flow (HAF), bile flow, and transaminases were measured. Liver tissue was taken 8 hrs after reperfusion for histology and immunohistochemistry. Results. HR, MAP, CVP, HAF, and PVF were comparable between the two groups. pONS significantly increased bile flow 8 hrs after reperfusion. ALT and AST were significantly lower after pONS. Histology showed significantly more severe necrosis and neutrophil infiltration in controls. pONS significantly decreased the index of immunohistochemical expression for TNF-α, MPO, and cleaved caspase-3 (P < 0.001). Conclusion. Administration of pONS before and after tissue damage protects the liver from warm IRI via mechanisms including decreasing oxidative stress, lipid peroxidation, apoptosis, and necrosis.

19.
Clin Transplant ; 25(6): 871-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21158925

RESUMO

In our study, BrdU-labeled marrow stem cells (MSCs) were directly (group 1), by the coronary artery (group 2), or by the ear vein (group 3) transplanted into myocardium to observe their distribution and differentiation in acute myocardial infarction (AMI) rabbit models. BrdU-positive cells, and BrdU and α-sarcomeric actin double positive cells were visible in the infarcted zones and its peripheral region. Cell processes between BrdU-positive cells and between BrdU-positive cells and host cardiomyocytes linked together. Transverse striation and sarcomere were seen. In above zones, new blood capillaries composed of Brdu-positive endothelial cells were present. Density of new blood capillaries was greater in group 1-3 than in control group (p < 0.05) and was the greatest in group 2. Hear function in group 1-3 was improved and was the best in group 2 (p < 0.05). In group 2 and 3, BrdU-positive cells were found in the lungs, liver, and kidneys. In group 3, BrdU-positive cells were greater in the lungs than in the liver and kidneys. We can see that MSCs transplanted by the three ways all can induce the regeneration of cardiomyocytes and blood capillaries. The order from good to poor effectiveness is group 2, group 1, and group 3.


Assuntos
Diferenciação Celular , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Isquemia Miocárdica/patologia , Isquemia Miocárdica/terapia , Animais , Medula Óssea , Feminino , Rim/citologia , Fígado/citologia , Pulmão/citologia , Masculino , Coelhos , Regeneração
20.
J Pineal Res ; 46(4): 365-72, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19552759

RESUMO

Free radicals are involved in pathophysiology of ischemia/reperfusion injury (IRI). Melatonin is a potent scavenger of reactive oxygen and nitrogen species. Thus, this study was designed to elucidate its effects in a model of rat kidney transplantation. Twenty Lewis rats were randomly divided into 2 groups (n = 10 animals each). Melatonin (50 mg/kg BW) dissolved in 5 mL milk was given to one group via gavage 2 hr before left donor nephrectomy. Controls were given the same volume of milk only. Kidney grafts were then transplanted into bilaterally nephrectomized syngeneic recipients after 24 hr of cold storage in Histidine-Tryptophan-Ketoglutarate solution. Both graft function and injury were assessed after transplantation through serum levels of blood urea nitrogen (BUN), creatinine, transaminases, and lactate dehydrogenase (LDH). Biopsies were taken to evaluate tubular damage, the enzymatic activity of superoxide dismutase (SOD) and lipid hydroperoxide (LPO), and the expression of NF-kBp65, inducible nitric oxide synthase (iNOS), caspase-3 as indices of oxidative stress, necrosis, and apoptosis, respectively. Melatonin improved survival (P < 0.01) while decreasing BUN, creatinine, transaminases, and LDH values up to 39-71% (P < 0.05). Melatonin significantly reduced the histological index for tubular damage, induced tissue enzymatic activity of SOD while reducing LPO. At the same time, melatonin down-regulated the expression of NF-kBp65, iNOS, and caspase-3. In conclusion, donor preconditioning with melatonin protected kidney donor grafts from IRI-induced renal dysfunction and tubular injury most likely through its anti-oxidative, anti-apoptotic and NF-kB inhibitory capacity.


Assuntos
Apoptose/efeitos dos fármacos , Transplante de Rim/métodos , Melatonina/farmacologia , NF-kappa B/antagonistas & inibidores , Traumatismo por Reperfusão/prevenção & controle , Condicionamento Pré-Transplante/métodos , Análise de Variância , Animais , Caspase 3/metabolismo , Histocitoquímica , Estimativa de Kaplan-Meier , Rim/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Estresse Oxidativo , Distribuição Aleatória , Ratos , Ratos Endogâmicos Lew , Traumatismo por Reperfusão/sangue , Superóxido Dismutase/metabolismo
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