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1.
Biosens Bioelectron ; 259: 116416, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38797033

RESUMO

The low abundance, heterogeneous expression, and temporal changes of miRNA in different cellular locations pose significant challenges for both the detection sensitivity of miRNA liquid biopsy and intracellular imaging. In this work, we report an intelligently assembled biosensor based on catalytic hairpin assembly (CHA) and aggregation-induced emission (AIE), named as catalytic hairpin aggregation-induced emission (CHAIE), for the ultrasensitive detection and intracellular imaging of miRNA-155. To achieve such goal, tetraphenylethylene-N3 (TPE-N3) is used as AIE luminogen (AIEgen), while graphene oxide is introduced to quench the fluorescence. When the target miRNA is present, CHA reaction is triggered, causing the AIEgen to self-assemble with the hairpin DNA. This will restrict the intramolecular rotation of the AIEgen and produce a strong AIE fluorescence. Interestingly, CHAIE does not require any enzyme or expensive thermal cycling equipment, and therefore provides a rapid detection. Under optimal conditions, the proposed biosensor can determine miRNA in the concentration range from 2 pM to 200 nM within 30 min, with the detection limit of 0.42 pM. The proposed CHAIE biosensor in this work offers a low background signal and high sensitivity, making it applicable for highly precise spatiotemporal imaging of target miRNA in living cells.


Assuntos
Técnicas Biossensoriais , Grafite , MicroRNAs , Nanocompostos , Grafite/química , MicroRNAs/análise , Técnicas Biossensoriais/métodos , Humanos , Nanocompostos/química , Corantes Fluorescentes/química , Limite de Detecção , Estilbenos/química , Catálise , Imagem Óptica/métodos , Espectrometria de Fluorescência/métodos , Fluorescência
2.
Nutr Metab Cardiovasc Dis ; 34(5): 1146-1156, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38220508

RESUMO

BACKGROUND AND AIMS: Carotid atherosclerosis is associated with an elevated risk of stroke in patients with chronic kidney disease. However, the molecular basis for the incidence of carotid atherosclerosis in patients with CKD is poorly understood. Here, we investigated whether circulating miR-423-5p is a crucial link between CKD and carotid atherosclerosis. METHODS AND RESULTS: We recruited 375 participants for a cross-sectional study to examine the occurrence of carotid plaque and plaque thicknesses. Levels of miR-423-5p were determined by qPCR analysis. We found that non-dialysis CKD patients had higher circulating exosomal and plasma miR-423-5p levels, and dialysis-dependent patients had lower miR-423-5p levels than non-dialysis CKD patients. After excluding for the influence of dialysis patients, linear regression analysis indicated that levels of circulating miR-423-5p are negatively correlated with eGFR (P < 0.001). Higher plasma miR-423-5p levels were associated with the incidence and severity of carotid plaques. In parallel, we constructed a murine model of CKD with a 5/6 nephrectomy protocol and performed RNA sequencing studies of aortic tissues. Consistent with these findings in CKD patients, circulating exosomal miR-423-5p levels in CKD mice were elevated. Furthermore, our RNA-seq studies indicated that the putative target genes of miR-423-5p were related to oxidative stress functions for aorta of CKD mice. CONCLUSION: Levels of miR-423-5p are associated with the presence and severity of carotid plaque in CKD. Data from our mouse model suggests that miR-423-5p likely influences gene expression programs related to oxidative stress in aorta of CKD mice.


Assuntos
Doenças das Artérias Carótidas , MicroRNAs , Placa Aterosclerótica , Insuficiência Renal Crônica , Humanos , Animais , Camundongos , Estudos Transversais , Doenças das Artérias Carótidas/epidemiologia , Doenças das Artérias Carótidas/genética , Doenças das Artérias Carótidas/complicações , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/genética , MicroRNAs/metabolismo
3.
Int Wound J ; 20(1): 173-182, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35673930

RESUMO

This study aimed to explore the risk factors for foot ulcer recurrence in patients with comorbid diabetic foot osteomyelitis (DFO) and diabetic nephropathy (DN). This is a prospective cohort study. Between May 2018 and May 2021, we selected 120 inpatients with comorbid severe diabetic foot infection (PEDIS Grade 3 or above) and DN for inclusion in our study. All cases were followed up for 36 months. The study outcomes were whether foot ulcer recurred and the time to recurrence. The risk factors of ulcer recurrence were analysed by comparing the data of the three groups. According to the recurrence of foot ulcer, the participants were divided into three groups: Group A (no foot ulcer recurrence, n = 89), Group B (foot ulcer recurrence within 12-36 months, n = 19) and Group C (foot ulcer recurrence within 6-12 months, n = 12). The multivariate Cox regression analysis showed that urine albumin-creatinine ratio (UACR) (HR: 1.008, 95% CI: 1.005-1.011, P < .001) and vibration perception threshold (VPT) (HR: 1.064, 95% CI: 1.032-1.096, P < .001) were identified as independent risk factors. Kaplan-Meier curves showed a significant positive association between UACR or VPT and the risk of foot ulcer recurrence (log rank, all P < .05). Areas under the ROC curves for UACR, VPT and the combination of UACR and VPT were 0.802, 0.799 and 0.842, respectively. The best cut-off values of UACR and VPT were 281.51 mg/g and 25.12 V, respectively. In summary, elevated UACR and VPT were independent risk factors. The best clinical cut-off values of UACR and VPT for prediction of foot ulcer recurrence were 281.51 mg/g and 25.12 V, respectively. Besides, our results suggested that microcirculation disorders rather than macrovascular complications play a major role in the recurrence of foot ulcer in patients with comorbid DFO and DN.


Assuntos
Diabetes Mellitus , Pé Diabético , Nefropatias Diabéticas , Osteomielite , Humanos , Pé Diabético/epidemiologia , Seguimentos , Estudos Prospectivos , Úlcera , Fatores de Risco , Osteomielite/epidemiologia
4.
Materials (Basel) ; 15(19)2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36234368

RESUMO

The utilization of recycled coarse aggregate (RCA) from construction and demolition waste (CDW) is a sustainable solution to protect the fragile natural environment and save the diminishing natural resources. The current study was aimed at exploring the impact resistance and mechanical properties of recycled aggregate concrete (RAC) affected by hooked-end steel fiber (HF) and crimped steel fiber (CF). Fifteen concrete mixtures considering different RCA substitution ratio, steel fiber dosage, and steel fiber shapes were designed. Meanwhile, a statistical analysis method-based Weibull distribution was introduced to evaluate the variations of impact test results, presented using a reliability function. Lastly, the microstructural morphologies of interfacial transition zones at the cement paste/aggregate and cement paste/fiber interfaces were observed using a scanning electron microscope (SEM). The experimental results showed that the impact resistance and mechanical properties mildly decreased with the increase in substitution ratio of RCA, whereas they conclusively increased with the increase in steel fiber content. Steel fiber recycled aggregate concrete (SFRAC) with 1.5% steel fiber content had the best impact resistance, and its initial cracking times and final failure times were 3.25-4.75 and 8.78-29.08 times those of plain RAC, respectively. HF has better impact resistance than CF. The SEM observations of microstructures indicated that the hardened cement paste of natural aggregate concrete (NAC) was more compact than that of RAC. Steel fiber had a better connection with the cement paste interface than that of aggregate and cement paste owing to better thermal conductivity. This research could be a guide for SFRAC as a structural material in practical engineering, steering the construction industry toward the circular economy.

5.
Cardiol J ; 29(4): 563-573, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33843041

RESUMO

BACKGROUND: Bioresorbable scaffolds (BRS) were considered to be beneficial for coronary bifurcation lesions regarding the avoidance of lateral branch opening incarceration after complete absorption. However, data is limited in this setting. The aim of this meta-analysis was to evaluate the short (6-month) and medium-term (1-year) outcomes of BRS in patients with coronary bifurcation lesions. METHODS: PubMed, EMBASE, Web of Science, Cochrane library databases were searched to find the studies of BRS implantation in patients with coronary bifurcation lesions. The effective outcome was target lesion revascularization. The safety outcomes included major adverse cardiovascular events, target vessel revascularization, myocardial infarction, definite or probable scaffold thrombosis, and cardiac death. RESULTS: A total of 1204 patients involved in 12 studies were included. The pooled estimate rate of target lesion revascularization as efficacy outcome was highly consistent between 6-month and 1-year follow-up, which was 4.74% (95% CI 2.36-9.54%, I² = 41.5%, p = 0.14) and 4.37% (95% CI 3.05-5.69%, I² = 4.6%, P = 0.39). The pooled estimated rate of major adverse cardiovascular events as safety outcome was 5.50% and 7.31% for both 6-month and 1-year follow-up. The pooled estimated rate of target vessel revascularization, myocardial infarction, definite or probable scaffold thrombosis, and cardiac death at 1-year follow-up was 5.92%, 2.52%, 1.69%, and 0.42%. CONCLUSIONS: The application of BRS for coronary bifurcation lesions is acceptable in efficacy outcome, but the high rate of scaffold thrombosis remains of concern (Registered by PROSPERO, CRD42019140341).


Assuntos
Doença da Artéria Coronariana , Infarto do Miocárdio , Intervenção Coronária Percutânea , Implantes Absorvíveis , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/cirurgia , Vasos Coronários , Morte , Humanos , Infarto do Miocárdio/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Desenho de Prótese , Resultado do Tratamento
6.
Front Cardiovasc Med ; 8: 655718, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34277725

RESUMO

Background: Patients with diabetes represent 20-30% of the population considered for percutaneous coronary intervention (PCI) and associate with more deleterious clinical outcome, which requires the optimal strategy of dual antiplatelet therapy (DAPT). The meta-analysis aims to compare clinical outcomes between very short (1-3 months) and standard (12 months) DAPT after implanting the second-generation drug-eluting stents in patients with or without diabetes following PCI. Methods and Analysis: PubMed, Embase, Web of Science, Ovid, Cochrane Library, and ClinicalTrials.gov were searched for studies comparing the very short term and standard DAPT in patients with or without diabetes following PCI. Risk ratio with 95% confidence intervals was used to evaluate the pooled effect of discontinuous variables, and the pooled analyses were performed with RevMan 5.3 and Stata SE 14.0 software. Results: A total of 38,864 patients were randomized to the very short term DAPT (N = 19,423) vs. standard DAPT (N = 19,441). Among them, 11,476 patients were diabetes and 27,388 patients were non-diabetes. The primary outcome of the net adverse clinical event (NACE) was significantly lower in diabetic patients with very short term DAPT (risk ratio 0.72, 95% CI 0.60-0.88, p = 0.0009). The same result was also found in the major cardiac or cerebrovascular events (MACCEs) (0.87, 0.78-0.98, p = 0.03). The risk of major or minor bleeding was significantly reduced in very short term DAPT regardless of the diabetes statue (0.69, 0.52-0.93, p = 0.01 in the diabetic group, and 0.50, 0.39-0.63, p <0.0001 in the non-diabetic group). There was no statistical difference in the incidence of major bleeding, all-cause death, cardiac death, myocardial infarction, definite or probable stent thrombosis, and stroke between the very short term DAPT (1-3 months) and standard DAPT (12 months) in patients with or without diabetes. Conclusion: The very short term DAPT can significantly reduce the risk of the NACE and MACCE in patients with diabetes compared to standard DAPT. Meanwhile, the very short term DAPT can also reduce the incidence of major and minor bleeding without increasing the risk of ischemia in patients with or without diabetes (Registered by PROSPERO, CRD42020192133). Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, Identifier: CRD42020192133.

7.
Int J Biol Macromol ; 182: 1528-1536, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34022308

RESUMO

A chitinase gene (PxChi52) from Paenibacillus xylanexedens Z2-4 was cloned and heterologously expressed in Escherichia coli BL21 (DE3). PxChi52 shared the highest identity of 91% with a glycoside hydrolase family 18 chitinase (ChiD) from Bacillus circulans. The recombinant enzyme (PxChi52) was purified and biochemically characterized. PxChi52 had a molecular mass of 52.8 kDa. It was most active at pH 4.5 and 65 °C, respectively, and stable in a wide pH range of 4.0-13.0 and up to 50 °C. The enzyme exhibited the highest specific activity of 16.0 U/mg towards colloidal chitin, followed by ethylene glycol chitin (5.4 U/mg) and ball milled chitin (0.4 U/mg). The Km and Vmax values of PxChi52 towards colloidal chitin were determined to be 3.06 mg/mL and 71.38 U/mg, respectively, PxChi52 hydrolyzed colloidal chitin and chitooligosaccharides with degree of polymerization 2-5 to release mainly N-acetyl chitobiose. In addition, PxChi52 displayed inhibition effects on the growth of some phytopathogenic fungi, including Alternaria alstroemeriae, Botrytis cinerea, Rhizoctonia solani, Sclerotinia sclerotiorum and Valsa mali. The unique properties of PxChi52 may enable it potential application in agriculture field as a biocontrol agent.


Assuntos
Antifúngicos/farmacologia , Quitinases/farmacologia , Ascomicetos/efeitos dos fármacos , Botrytis/efeitos dos fármacos , Quitina/análogos & derivados , Quitina/química , Quitosana , Dissacarídeos/química , Oligossacarídeos , Paenibacillus/enzimologia , Rhizoctonia/efeitos dos fármacos
8.
J Interv Cardiol ; 2021: 6699812, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33935601

RESUMO

OBJECTIVE: The effect of postdilation in patients with acute coronary syndrome is still controversial. This meta-analysis aims to analyze the clinical and angiographic outcomes of postdilation after percutaneous coronary intervention in patients with acute coronary syndrome. METHODS: PubMed, Embase, the Cochrane Library, Web of Science, CNKI, and Wangfang databases were searched from inception to August 30, 2020. Eligible studies from acute coronary syndrome patients treated with postdilation were included. The primary clinical outcome was major adverse cardiovascular events (MACE), the secondary clinical outcomes comprised all-cause death, stent thrombosis, myocardial infarction, and target vessel revascularization, and the angiographic outcomes were no reflow and slow reflow. RESULTS: 11 studies met inclusion criteria. In clinical outcomes, our pooled analysis demonstrated that the postdilation had a tendency of decreasing MACE (OR = 0.67, 95% CI 0.45-1.00; P = 0.05) but significantly increased all-cause death (OR = 1.49, 95% CI 1.05-2.12; P = 0.03). No significant difference existed in stent thrombosis (OR = 0.71, 95% CI 0.40-1.26; P = 0.24), myocardial infarction (OR = 1.40, 95% CI 0.51-3.83; P = 0.51), and target vessel revascularization (OR = 0.61, 95% CI 0.21-1.80; P = 0.37) between postdilation and non-postdilation groups. In angiographic outcomes, there were no significant differences in no reflow (OR = 1.19, 95% CI 0.54-2.65; P = 0.66) and slow reflow (OR = 1.12, 95% CI 0.93-1.35; P = 0.24) between two groups. CONCLUSIONS: The postdilation tends to reduce the risk of MACE but significantly increases all-cause death, without significantly affecting stent thrombosis, myocardial infarction, target vessel revascularization, and coronary TIMI flow grade. However, more randomized controlled trials are required for investigating the effect of postdilation for patients with acute coronary syndrome (registered by PROSPERO, CRD42020160748).


Assuntos
Síndrome Coronariana Aguda/terapia , Angioplastia Coronária com Balão , Intervenção Coronária Percutânea , Síndrome Coronariana Aguda/etiologia , Angioplastia Coronária com Balão/efeitos adversos , Angioplastia Coronária com Balão/métodos , Humanos , Intervenção Coronária Percutânea/efeitos adversos , Stents , Resultado do Tratamento
9.
Front Cardiovasc Med ; 8: 598046, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33959639

RESUMO

Background and Objectives: The second-generation drug-eluting stents have been used to treat chronic total occlusion lesion. However, there is limited evidence of the clinical outcomes that whether the second-generation drug-eluting stents is superior to first-generation ones in patients with chronic total occlusion lesion undergoing percutaneous coronary intervention. The study aimed to compare the differences in clinical outcomes between the two generations drug-eluting stents in patients with those by a meta-analysis. Methods: PubMed, Embase, the Cochrane library and Web of science databases were systemically searched before March, 2021. Randomized controlled trials and observational studies were included to compare the second-generation drug-eluting stents with the first-generation ones in patients with chronic total occlusion lesion undergoing percutaneous coronary intervention. The clinical outcomes were major adverse cardiac events (MACE), target vessel revascularization, myocardial infarction, all-cause death. Fixed effects models were used to calculate the odds ratio (OR) and 95% confidence interval (CI) of each clinical outcome. Sensitivity analysis was performed to detect potential sources of heterogeneity. Subgroup analyses were used to assess the differential effects. Results: The meta-analysis included eight studies involving 4,583 patients with chronic total occlusion lesion undergoing percutaneous coronary intervention. Pooled analysis showed that the incidence of MACE (OR = 0.68, 95%CI 0.54-0.85, P = 0.0008), target vessel revascularization (OR = 0.70, 95%CI 0.54-0.91, P = 0.007), and myocardial infarction (OR = 0.58, 95%CI 0.37-0.93, P = 0.02) were lower in the second-generation drug-eluting stents compared with the first-generation ones. However, there was not difference in all-cause deaths between two drug-eluting stents (OR = 0.67, 95%CI 0.45-1.01, P = 0.05). Conclusions: The second-generation drug-eluting stents are associated with lower MACE, target vessel revascularization, and myocardial infarction compared with the first-generation ones in patients with chronic total occlusion lesion undergoing percutaneous coronary intervention. The results of this study can provide a reference for the selection of stents in patients with chronic total occlusion lesion. Further randomized controlled trials are needed to verify that the second-generation drug-eluting stents is superior to the first-generation ones in patients with chronic total occlusion (Registered by PROSPERO, CRD42020158406).

10.
Front Cardiovasc Med ; 8: 615396, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33614748

RESUMO

Background and Objective: The optimum duration of dual antiplatelet therapy (DAPT) remains uncertain in patients with acute coronary syndrome treated with new generation stents. This meta-analysis was performed to investigate ischemia and bleeding outcomes with different DAPT strategies. Methods: PubMed, Embase, Cochrane and Web of science from inception to May 27, 2020, were systematically searched. Randomized controlled trials were included to compare short-term (6 months or less) with standard (12 months) DAPT in patients with acute coronary syndrome treated with new generation stents. The primary endpoints were myocardial infarction, definite or probable stent thrombosis and major bleeding. The secondary endpoints included all-cause death, cardiovascular death, stroke, target vessel revascularization and net adverse clinical events. Random effect model and fixed effect model were used to calculate the odds ratio (OR) and 95% confidence interval (CI) of each endpoint. Results: Four randomized controlled trials and seven subgroup analyses of larger randomized controlled trials, including a total of 21,344 patients with acute coronary syndrome, met our inclusion criteria. The shorter DAPT was associated with significantly lower major bleeding compared with the standard DAPT (OR 0.71, 95% CI 0.56-0.90, P = 0.005, I 2 = 25%), while without increasing the risk of myocardial infarction (OR 1.18, 0.88-1.58, P = 0.28, I 2 = 20%), definite or probable stent thrombosis (OR 1.60, 0.98-2.59, P = 0.06, I 2 = 0%). No significantly difference was observed in the risk of all-cause death (OR 0.96, 0.72-1.27, P = 0.76, I 2 = 2%), cardiovascular death (OR 0.91, 0.62-1.33, P = 0.62, I 2 = 0%), stroke (OR 0.84, 0.54-1.30, P = 0.43, I 2 = 0%), target vessel revascularization (OR 1.14, 0.84-1.55, P = 0.41, I 2 = 8%), and net adverse clinical events (OR 0.93, 0.80-1.07, P = 0.3, I 2 = 18%) between the two groups. Conclusions: In patients with acute coronary syndrome treated with new generation stents, the shorter DAPT leads to a marked reduction in the risk of major bleeding compared with the standard DAPT. This benefit is achieved without increasing the risk of mortality or ischemic outcomes. The study protocol was registered in PROSPERO (CRD42020189871).

11.
Medicine (Baltimore) ; 100(1): e24151, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33429796

RESUMO

ABSTRACT: Coronavirus disease 2019 (COVID-19) is still developing worldwide. The prognosis of the disease will become worse and mortality will be even higher when it is combined with cardiovascular disease. Furthermore, COVID-19 is highly infectious and requires strict isolation measures. For acute coronary syndromes (ACS), a common cardiovascular disease, infection may aggravate the occurrence and development of ACS, making the management of more difficult. It will be an enormous challenge for clinical practice to deal with ACS in this setting of COVID-19.Aim to reduce the mortality of ACS patients during the epidemic of COVID-19 by standardizing procedures as much as possible.Pubmed and other relevant databases were searched to retrieve articles on COVID-19 and articles on ACS management strategies during previous influenza epidemics. The data was described and synthesized to summarize the diagnosis and management strategy of ACS, the preparation of catheter laboratory, and the protection of the medical staff in the context of COVID-19. Ethical approval is not required in this study, because it is a review with no recourse to patient identifiable information.Standardized diagnosis and treatment advice can help reduce the mortality of COVID-19 patients with ACS. In the absence of contraindications, the third generation of thrombolytic drugs should be the first choice for thrombolytic treatment in the isolation ward. For patients who have to receive PCI, this article provides detailed protective measures to avoid nosocomial infection.


Assuntos
Síndrome Coronariana Aguda/terapia , Síndrome Coronariana Aguda/virologia , COVID-19/epidemiologia , Infecção Hospitalar/prevenção & controle , Controle de Infecções/normas , Pneumonia Viral/epidemiologia , Síndrome Coronariana Aguda/mortalidade , COVID-19/transmissão , Humanos , Pandemias , Pneumonia Viral/virologia , SARS-CoV-2
12.
Platelets ; 32(5): 582-590, 2021 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-32627616

RESUMO

Dual antiplatelet therapy (DAPT) is the basis of preventing stent thrombosis and ischemic events after percutaneous coronary intervention (PCI), but prolonging the duration of DAPT will increase the risk of bleeding. The optimal duration of DAPT after PCI remains controversial at present. The purpose of this meta-analysis was to investigate the efficacy and safety of short-term DAPT in patients undergoing PCI. PubMed, Embase, Cochrane and Web of science from inception to September 2019 were systematically searched. Randomized controlled trials were included to compare short term (3 months or less) with a standard 12-months DAPT in patients undergoing PCI. Random effect model and fixed effect model wereused to calculate the risk ratio (RR) and 95% confidence interval (CI) of each endpoint. This meta-analysis included 38479 patients undergoing PCI from 8 randomized clinical trials. No difference was observed in the risk of all-cause death (RR 0.92, 95% CI 0.80-1.06, P = 0.25), cardiovascular death (RR 0.88, 0.69-1.12, P = 0.29), myocardial infarction (RR 1.05, 0.94-1.19, P = 0.38), definite or probable stent thrombosis (RR 1.05, 0.80-1.36, P = 0.73), and stroke (RR 1.02, 0.80-1.30, P = 0.89) between short term and standard DAPT. The short-term DAPT could reduce the risk of major bleeding (RR 0.67, 0.48-0.94, P = 0.02) and any bleeding (RR 0.63, 0.48-0.82, P = 0.0005) compared with 12 months of DAPT. In conclusion, the short-term DAPT can reduce the risk of bleeding compared with standard DAPT, without increasing the risk of death or ischemia (Registered by PROSPERO, CRD42020153881).


Assuntos
Intervenção Coronária Percutânea/métodos , Inibidores da Agregação Plaquetária/uso terapêutico , Feminino , Humanos , Masculino , Inibidores da Agregação Plaquetária/farmacologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Tempo , Resultado do Tratamento
13.
Biotechnol Lett ; 42(8): 1489-1499, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32170432

RESUMO

OBJECTIVES: Chitinases play important role in chitin bioconversion, while few of them have been put into use due to their poor properties. We aimed to identify and characterize chitinases suitable for N-acetyl chitooligosaccharides (COSs) production from chitin materials. RESULTS: A chitinase gene (SsChi28) from Streptomyces sampsonii XY2-7 was cloned and heterologously expressed in E. coli BL21 (DE3) as an active protein. The deduced protein shared high sequence identities and structure similarities with some glycoside hydrolase family 19 chitinases. The recombinant enzyme (SsChi28) was purified and biochemically characterized. SsChi28 was a monomeric protein with a molecular mass of 30 kDa estimated by SDS-PAGE. It was most active at pH 6.0 and 55 °C, respectively, and stable in a wide pH range of 3.5-11.5 and up to 60 °C. The enzyme exhibited strict substrate specificities towards ethylene glycol chitin (222.3 U/mg) and colloidal chitin (20.1 U/mg). Besides, it displayed lysozyme activity against Micrococcus lysodeikticus. SsChi28 hydrolyzed colloidal chitin to yield mainly N-acetyl chitobiose, accounting high up to 73% (w/w) in total products. CONCLUSION: The excellent enzymatic properties of SsChi28 may make it potential in chitin bioconversion (especially for N-acetyl COS production), as well as in biological control of fungal diseases.


Assuntos
Proteínas de Bactérias , Quitinases , Dissacarídeos/metabolismo , Muramidase , Streptomyces , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Quitinases/química , Quitinases/genética , Quitinases/metabolismo , Estabilidade Enzimática , Escherichia coli/genética , Muramidase/química , Muramidase/genética , Muramidase/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Streptomyces/enzimologia , Streptomyces/genética , Especificidade por Substrato
14.
Polymers (Basel) ; 11(7)2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31277244

RESUMO

A novel hierarchical metamaterial with tunable negative Poisson's ratio is designed by a re-entrant representative unit cell (RUC), which consists of star-shaped subordinate cells. The in-plane mechanical behaviors of star-re-entrant hierarchical metamaterial are studied thoroughly by finite element method, non-dimensional effective moduli and effective Poisson's ratios (PR) are obtained, then parameters of cell length, inclined angle, thickness for star subordinate cell as well as the amount of subordinate cell along x, y directions for re-entrant RUC are applied as adjustable design variables to explore structure-property relations. Finally, the effects of the design parameters on mechanical behavior and relative density are systematically investigated, which indicate that high specific stiffness and large auxetic deformation can be remarkably enhanced and manipulated through combining parameters of both subordinate cell and parent RUC. It is believed that the new hierarchical metamaterial reported here will provide more opportunities to design multifunctional lightweight materials that are promising for various engineering applications.

15.
J Orthop Surg Res ; 14(1): 56, 2019 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-30782196

RESUMO

BACKGROUND: Recently, many studies have shown the role of hypoxia-inducible factor-1α (HIF-1α) expression in the outcome of bone tumor. However, the results remain inconclusive. It is necessary to carry out a meta-analysis of all the current available data to clarify the relationship between HIF-1α and survival or clinicopathological features of bone tumor. METHODS: PubMed, Cochrane Library, Web of Science, China National Knowledge Internet, and Wanfang databases were used to search the relationship between HIF-1α and bone tumor. Articles investigating clinicopathological and prognostic value of HIF-1α in bone tumor patients were enrolled in this meta-analysis. Overlapping articles, duplicate data, reviews, case reports, and letters without original data were excluded. The pooled risk ratios (RRs) and hazard ratios (HRs) were used to evaluate the clinicopathological and prognostic value of HIF-1α on bone tumor patients, respectively. RESULTS: A total of 28 studies including 1443 patients were included in this meta-analysis, which were involved in three different types of bone tumor including 3 chondrosarcomas, 2 giant cell tumors of bone, and 23 osteosarcomas. Our results showed that high expression levels of HIF-1α were associated with poorer OS (overall survival) (HR = 2.61, 95% CI 2.11-3.23, P <  0.001) and shorter DFS (disease-free survival) (HR = 2.02, 95% CI 1.41-2.89, P <  0.001) in bone tumor. In addition, this study also analyzed the role of HIF-1α expression in clinicopathological features, which were closely related with the severity of bone tumor, including differentiation, clinical stage, metastasis, and microvessel density. Our results indicated that HIF-1α overexpression was significantly associated with differentiation (RR = 1.56, 95% CI 1.00-2.43, P = 0.049), clinical stage (RR = 1.75, 95% CI 1.25-2.45, P = 0.001), metastasis (RR = 1.78, 95% CI 1.58-2.00, P <  0.001), and microvessel density (SMD = 2.34, 95% CI 1.35-3.34, P <  0.001) of bone tumor. CONCLUSIONS: HIF-1α overexpression indicated an unfavorable factor for OS and DFS in bone tumor, suggesting that HIF-1α may serve as a potential prognostic marker for bone tumor.


Assuntos
Biomarcadores Tumorais/biossíntese , Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/patologia , Regulação Neoplásica da Expressão Gênica , Subunidade alfa do Fator 1 Induzível por Hipóxia/biossíntese , Biomarcadores Tumorais/genética , Neoplasias Ósseas/epidemiologia , China/epidemiologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Prognóstico
16.
Artigo em Inglês | MEDLINE | ID: mdl-29189750

RESUMO

As excess water is discharged from a high dam, low frequency noise (air pulsation lower than 10 Hz, LFN) is generated and propagated in the surrounding areas, causing environmental hazards such as the vibration of windows and doors and the discomfort of local residents. To study the generation mechanisms and key influencing factors of LFN induced by flood discharge and energy dissipation from a high dam with a ski-jump type spillway, detailed prototype observations and analyses of LFN are carried out. The discharge flow field is simulated and analyzed using a gas-liquid turbulent flow model. The acoustic response characteristics of the air cavity, which is formed between the discharge nappe and dam body, are analyzed using an acoustic numerical model. The multi-sources generation mechanisms are first proposed basing on the prototype observation results, vortex sound model, turbulent flow model and acoustic numerical model. Two kinds of sources of LFN are studied. One comes from the energy dissipation of submerged jets in the plunge pool, the other comes from nappe-cavity coupled vibration. The results of the analyses reveal that the submerged jets in the plunge pool only contribute to an on-site LFN energy of 0-1.0 Hz, and the strong shear layers around the high-velocity submerged jets and wall jet development areas are the main acoustic source regions of LFN in the plunge pool. In addition, the nappe-cavity coupled vibration, which is induced when the discharge nappe vibrates with close frequency to the model frequency of the cavity, can induce on-site LFN energy with wider frequency spectrum energy within 0-4.0 Hz. By contrast, the contribution degrees to LFN energy from two acoustic sources are almost same, while the contribution degree from nappe-cavity coupled vibration is slightly higher.


Assuntos
Inundações , Ruído , Centrais Elétricas , Vibração , Acústica , China , Humanos
17.
Artigo em Inglês | MEDLINE | ID: mdl-27314374

RESUMO

As flood water is discharged from a high dam, low frequency (i.e., lower than 10 Hz) noise (LFN) associated with air pulsation is generated and propagated in the surrounding areas, causing environmental problems such as vibrations of windows and doors and discomfort of residents and construction workers. To study the generation mechanisms and key influencing factors of LFN induced by energy dissipation through submerged jets at a high dam, detailed prototype observations and analyses of LFN are conducted. The discharge flow field is simulated using a gas-liquid turbulent flow model, and the vorticity fluctuation characteristics are then analyzed. The mathematical model for the LFN intensity is developed based on vortex sound theory and a turbulent flow model, verified by prototype observations. The model results reveal that the vorticity fluctuation in strong shear layers around the high-velocity submerged jets is highly correlated with the on-site LFN, and the strong shear layers are the main regions of acoustic source for the LFN. In addition, the predicted and observed magnitudes of LFN intensity agree quite well. This is the first time that the LFN intensity has been shown to be able to be predicted quantitatively.


Assuntos
Inundações , Modelos Teóricos , Ruído , Acústica
18.
Int J Syst Evol Microbiol ; 65(10): 3734-3738, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26228463

RESUMO

A halophilic archaeal strain, YC93T, was isolated from Yuncheng salt lake in Shanxi Province, China. Cells were pleomorphic rods, stained Gram-negative and formed light-red-pigmented colonies on agar plates. Strain YC93T was able to grow at 25­50 °C (optimum 37 °C), with 1.4­4.8 M NaCl (optimum 2.0 M), with 0­1.0 M MgCl2 (optimum 0.05 M) and at pH 6.0­9.5 (optimum pH 7.0). Cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 8 % (w/v). 16S rRNA gene sequence analysis revealed that strain YC93T had two dissimilar 16S rRNA genes both of which were phylogenetically related to those of the two recognized members of the genus Halorussus (93.0­95.3 % similarity). The rpoB' gene of strain YC93T was phylogenetically related to the corresponding gene of Halorussus rarus TBN4T (91.3 % similarity) and Halorussus ruber YC25T (90.5 %). The major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and five glycolipids chromatographically identical to those of Halorussus rarus CGMCC 1.10122T. The DNA G+C content of strain YC93T was 64.6 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YC93T represents a novel species of the genus Halorussus, for which the name Halorussus amylolyticus sp. nov. is proposed. The type strain is YC93T ( = CGMCC 1.12126T = JCM 18367T).


Assuntos
Halobacteriaceae/classificação , Lagos/microbiologia , Filogenia , Salinidade , Composição de Bases , China , DNA Arqueal/genética , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Glicolipídeos/química , Halobacteriaceae/genética , Halobacteriaceae/isolamento & purificação , Dados de Sequência Molecular , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Microbiologia da Água
19.
Curr Microbiol ; 71(3): 382-6, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26134535

RESUMO

Halophilic archaeal strain YC89(T) was isolated from Yuncheng salt lake in Shanxi, China. Cells from strain YC89(T) were short rods, lysed in distilled water, stained Gram-negative and formed red-pigmented colonies on agar plate. Strain YC89(T) was able to grow at 25-50°C (optimum 37°C), at 1.4-4.8 M NaCl (optimum 2.6-3.1 M), at 0-1.0 M MgCl2 (optimum 0.3 M) and at pH 6.0-9.5 (optimum pH 7.5). The major polar lipids are phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, sulfated mannosyl glucosyl diether and two unknown glycolipids. 16S rRNA gene analysis revealed that strain YC89(T) was phylogenetically related to Halorientalis persicus D108(T) (95.6% nucleotide identity) and H. regularis TNN28(T) (95.3% nucleotide identity). The rpoB' gene similarities between strain YC89(T) and H. persicus IBRC-M 10043(T) and H. regularis TNN28(T) were 88.1 and 88.0%, respectively. The DNA G+C content of strain YC89(T) was determined to be 61.3 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YC89(T) (=CGMCC 1.12125(T) = JCM 18366(T)) represents a new species of Halorientalis, for which the name H. brevis sp. nov. is proposed.


Assuntos
Lagos/microbiologia , Composição de Bases , China , Análise por Conglomerados , Citosol/química , DNA Arqueal/química , DNA Arqueal/genética , DNA Ribossômico/química , DNA Ribossômico/genética , RNA Polimerases Dirigidas por DNA , Glicolipídeos/análise , Halobacteriaceae , Dados de Sequência Molecular , Fosfolipídeos/análise , Filogenia , Pigmentos Biológicos/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo , Temperatura
20.
Arch Microbiol ; 197(7): 949-53, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26123238

RESUMO

Halophilic archaeal strain XD48(T) was isolated from a Chinese marine solar saltern. Cells were pleomorphic, stained Gram-negative and formed red-pigmented colonies on solid media. Strain XD48(T) was found to be able to grow at 25-50 °C (optimum 37 °C), at 0.9-4.8 M NaCl (optimum 3.1 M NaCl), at 0-1.0 M MgCl2 (optimum 0.3 MgCl2) and at pH 5.0-9.5 (optimum pH 6.5). The cells lysed in distilled water, and the minimal NaCl concentration to prevent cell lysis was found to be 5% (w/v). The major polar lipids of the strain were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS), sulfated galactosyl mannosyl glucosyl diether (S-TGD-1), sulfated mannosyl glucosyl diether (S-DGD-1) and six unknown glycolipids. The 16S rRNA gene and rpoB' gene of strain XD48(T) were phylogenetically related to the corresponding genes of Haloarchaeobius members (92.4-93.9 and 89.6-90.5% similarities, respectively). The DNA G + C content of strain XD48(T) was determined to be 65.3 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain XD48(T) (=CGMCC 1.12230(T) = JCM 18642(T)) represents a new species of Haloarchaeobius, for which the name Haloarchaeobius amylolyticus sp. nov. is proposed.


Assuntos
Halobacteriaceae/classificação , Filogenia , Água do Mar/microbiologia , Composição de Bases , China , DNA Arqueal/genética , Halobacteriaceae/química , Halobacteriaceae/genética , Halobacteriaceae/isolamento & purificação , Lipídeos/análise , RNA Ribossômico 16S/genética , Especificidade da Espécie
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