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1.
Inorg Chem ; 63(13): 6075-6081, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38506110

RESUMO

Ruddlesden-Popper oxyfluorides La2Ni1-xCuxO3F2 (0 ≤ x ≤ 1) were obtained by topochemical reaction of oxide precursors La2Ni1-xCuxO4, prepared by citrate-based soft chemistry synthesis, with polyvinylidene fluoride (PVDF) as the fluorine source. Systematic changes of the crystal structure in the oxide as well as the oxyfluoride substitution series were investigated. For 0.2 ≤ x ≤ 0.9, the oxyfluorides adopt the monoclinic (C2/c) structural distortion previously solved for the x = 0.8 compound based on neutron powder diffraction data, whereas the sample with a lower Cu content of x = 0.1 crystallizes in the orthorhombic (Cccm) structure variant of La2NiO3F2. The orthorhombic-to-monoclinic structural transition was found to be the result of an additional tilt component of the Jahn-Teller elongated CuO4F2 octahedra. The structural transitions were additionally studied by DFT calculations, confirming the monoclinic space group symmetry. The "channel-like" anionic ordering of the endmembers La2NiO3F2 and La2CuO3F2 was checked by 19F MAS NMR experiments and was found to persist throughout the entire substitution series.

2.
World J Gastroenterol ; 29(39): 5435-5451, 2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37900996

RESUMO

Small extracellular vesicles (exosomes) are important components of the tumor microenvironment. They are small membrane-bound vesicles derived from almost all cell types and play an important role in intercellular communication. Exosomes transmit biological molecules obtained from parent cells, such as proteins, lipids, and nucleic acids, and are involved in cancer development. MicroRNAs (miRNAs), the most abundant contents in exosomes, are selectively packaged into exosomes to carry out their biological functions. Recent studies have revealed that exosome-delivered miRNAs play crucial roles in the tumorigenesis, progression, and drug resistance of hepatocellular carcinoma (HCC). In addition, exosomes have great industrial prospects in the diagnosis, treatment, and prognosis of patients with HCC. This review summarized the composition and function of exosomal miRNAs of different cell origins in HCC and highlighted the association between exosomal miRNAs from stromal cells and immune cells in the tumor microenvironment and the progression of HCC. Finally, we described the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC.


Assuntos
Carcinoma Hepatocelular , Exossomos , Vesículas Extracelulares , Neoplasias Hepáticas , MicroRNAs , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , Carcinoma Hepatocelular/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , Neoplasias Hepáticas/metabolismo , Exossomos/genética , Exossomos/metabolismo , Vesículas Extracelulares/metabolismo , Microambiente Tumoral/genética
3.
J Phys Chem Lett ; 14(44): 9969-9977, 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37905788

RESUMO

We study two-dimensional noble metal chalcogenides, with compositions {Cu, Ag, Au}2{S, Se, Te}, crystallizing in a snub-square lattice. This is a semiregular two-dimensional tesselation formed by triangles and squares that exhibits geometrical frustration. We use for comparison a square lattice, from which the snub-square tiling can be derived by a simple rotation of the squares. The monolayer snub-square chalcogenides are very close to thermodynamic stability, with the most stable system (Ag2Se) a mere 7 meV/atom above the convex hull of stability. All compounds studied in the square and snub-square lattice are semiconductors, with band gaps ranging from 0.1 to more than 2.5 eV. Excitonic effects are strong, with an exciton binding energy of around 0.3 eV. We propose the Cu (001) surface as a possible substrate to synthesize Cu2Se, although many other metal and semiconducting surfaces can be found with very good lattice matching.

4.
Adv Mater ; 35(22): e2210788, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36949007

RESUMO

Crystal-graph attention neural networks have emerged recently as remarkable tools for the prediction of thermodynamic stability. The efficacy of their learning capabilities and their reliability is however subject to the quantity and quality of the data they are fed. Previous networks exhibit strong biases due to the inhomogeneity of the training data. Here a high-quality dataset is engineered to provide a better balance across chemical and crystal-symmetry space. Crystal-graph neural networks trained with this dataset show unprecedented generalization accuracy. Such networks are applied to perform machine-learning-assisted high-throughput searches of stable materials, spanning 1 billion candidates. In this way, the number of vertices of the global T = 0 K phase diagram is increased by 30% and find more than ≈150 000 compounds with a distance to the convex hull of stability of less than 50 meV atom-1 . The discovered materials are then accessed for applications, identifying compounds with extreme values of a few properties, such as superconductivity, superhardness, and giant gap-deformation potentials.

5.
Oxid Med Cell Longev ; 2022: 7608712, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36071871

RESUMO

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase involved in cell proliferation, invasion, angiogenesis, and metastasis in various cancers, including hepatocellular carcinoma (HCC). However, the role and molecular mechanisms of EZH2 in HCC radiosensitivity remain unclear. Here, we show that EZH2 is upregulated in HCC cells and the aberrantly overexpressed EZH2 is associated with the poor prognosis of HCC patients. Using miRNA databases, we identified miR-138-5p as a regulator of EZH2. We also found that miR-138-5p was suppressed by EZH2-induced H3K27me3 in HCC cell lines. MiR-138-5p overexpression and EZH2 knockdown enhanced cellular radiosensitivity while inhibiting cell migration, invasion, and epithelial-mesenchymal transition (EMT). Analysis of RNA-seq datasets revealed that the hypoxia-inducible factor-1 (HIF-1) signaling pathway was the main enrichment pathway for differential genes after miR-138-5p overexpression or EZH2 knockdown. Expression level of HIF-1α was significantly suppressed after miR-138-5p overexpression or silencing of EZH2. HIF-1α silencing mitigated resistance of HCC cells and inhibited EMT. This study establishes the EZH2/miR-138-5p/HIF-1α as a potential therapeutic target for sensitizing HCC to radiotherapy.


Assuntos
Carcinoma Hepatocelular , Proteína Potenciadora do Homólogo 2 de Zeste , Subunidade alfa do Fator 1 Induzível por Hipóxia , Neoplasias Hepáticas , MicroRNAs , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/radioterapia , Linhagem Celular Tumoral , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/radioterapia , MicroRNAs/genética , MicroRNAs/metabolismo , Tolerância a Radiação/genética
6.
Sci Data ; 9(1): 64, 2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35236866

RESUMO

In the past decade we have witnessed the appearance of large databases of calculated material properties. These are most often obtained with the Perdew-Burke-Ernzerhof (PBE) functional of density-functional theory, a well established and reliable technique that is by now the standard in materials science. However, there have been recent theoretical developments that allow for increased accuracy in the calculations. Here, we present a dataset of calculations for 175k crystalline materials obtained with two functionals: geometry optimizations are performed with PBE for solids (PBEsol) that yields consistently better geometries than the PBE functional, and energies are obtained from PBEsol and from SCAN single-point calculations at the PBEsol geometry. Our results provide an accurate overview of the landscape of stable (and nearly stable) materials, and as such can be used for reliable predictions of novel compounds. They can also be used for training machine learning models, or even for the comparison and benchmark of PBE, PBEsol, and SCAN.

7.
Jpn J Infect Dis ; 75(1): 31-35, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-34053953

RESUMO

This study aimed to investigate the clinical features, distribution, and antimicrobial susceptibility of Nocardia species isolated from pulmonary nocardiosis cases in a tertiary hospital in China. The species were collected from January 1, 2018, to May 31, 2019, and identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry or polymerase chain reaction. Antimicrobial susceptibility testing was performed using the broth microdilution method. Within the 44 Nocardia species, N. farcinica was the most frequently identified species (n = 36), followed by N. nova (n = 5), N. otitidiscaviarum (n = 1), N. cyriacigeorgica (n = 1), and N. transvalensis (n = 1). The top 3 predisposing factors of pulmonary nocardiosis were chronic obstructive pulmonary disease (45.5%), hypertension (34.1%), and tuberculosis (31.8%). All 44 Nocardia species were susceptible to amikacin, trimethoprim/sulfamethoxazole, and linezolid. The resistance rates of Nocardia to amoxicillin-clavulanic acid, ciprofloxacin, clarithromycin, ceftriaxone, tobramycin, and imipenem were 4.5%, 9.1%, 79.5%, 72.7%, 63.6%, and 38.6%, respectively. Two Nocardia strains had decreased sensitivity to trimethoprim/sulfamethoxazole. In conclusion, N. farcinica was the most frequently isolated Nocardia species in the First Hospital of Changsha. All the isolated clinical Nocardia species showed susceptibility to amikacin, trimethoprim/sulfamethoxazole, and linezolid, suggesting that these drugs can be primary therapeutic choices for treating Nocardia infections.


Assuntos
Nocardiose , Nocardia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Humanos , Testes de Sensibilidade Microbiana , Nocardia/genética , Nocardiose/tratamento farmacológico , Nocardiose/epidemiologia , Centros de Atenção Terciária , Combinação Trimetoprima e Sulfametoxazol
8.
Inorg Chem ; 60(17): 13646-13657, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34492764

RESUMO

We report on the new Ruddlesden-Popper (RP) oxyfluoride La2NiO2.5F3 containing an unprecedented high amount of fluorine and Ni2+. This oxyfluoride was prepared by topochemical low-temperature fluorination of La2NiO4, which was obtained by a soft chemistry synthesis, with poly(vinylidene difluoride) (PVDF) as fluorinating agent. La2NiO2.5F3 is the first n = 1 RP compound crystallizing in the tetragonal space group P42/nnm (a = 5.7297(6) Å and c = 13.0106(2) Å). The crystal structure shows a unique tilting scheme of the NiO4F2 octahedra that has so far been only theoretically predicted. Combined neutron and X-ray powder diffraction experiments together with bond-valence-sum and DFT+U calculations reveal an unusual anion ordering with fluoride being located on the apical anion sites of the NiO4F2 octahedra. Excess fluorine ions were found to populate two of the four interstitial anion sites in an ordered fashion. A third interstitial anion position is occupied by oxygen ions while the fourth site remains unoccupied. This hitherto unobserved ordering scenario in RP oxyfluorides promotes a strong layerwise alternating tilting of the NiO4F2 octahedra. Magnetic measurements show strong antiferromagnetic interactions with a high Néel temperature of about 225 K and a pronounced ZFC/FC splitting most likely as the result of a small ferromagnetic moment arising from spin canting. The electronic structure was characterized by DFT and UV-vis spectroscopy, and a strong increase of Eg was found compared to La2NiO4 (3.4 eV vs 1.3 eV).

9.
J Phys Chem Lett ; 12(20): 4972-4979, 2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34014100

RESUMO

We perform a theoretical study of an atomically thin, two-dimensional layer obtained by positioning atoms at the vertices of the classical Pythagorean tiling. This leads to an unusual geometrical pattern that is only stable for the three halogens Cl, Br, and I. In this Pythagorean structure, halogen atoms are arranged in strongly bound diatomic units that bind together by weaker electrostatic bonds. The energy of these phases is competitive with those of the low-temperature phase of the halogens and the two-dimensional layer obtained by exfoliating it. The Pythagorean layers are semiconducting, with an unusual band structure composed of very mobile holes and extremely heavy electrons. They are also soft, exhibiting small values of the elastic constants and a very low energy flexural mode. Analysis of the allowed Raman transitions reveals breathing-like modes that might be used to fingerprint, experimentally, the Pythagorean structure. Finally, we present a series of substrates that, due to lattice matching and compatible symmetry, can be used to stabilize these peculiar two-dimensional layers.

10.
BMC Microbiol ; 20(1): 281, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32928115

RESUMO

BACKGROUND: Acinetobacter baumannii has traditionally been considered an opportunistic pathogen with low virulence. In this study, we characterized the carbapenem-resistant hypervirulent A. baumannii (CR-hvAB) stains isolated from our hospital in mid-south region of China. RESULTS: Blood samples collected between January 2017 and May 2019 were used for virulence experiments and biofilm assays of individual carbapenem-resistant A. baumannii (CR-AB) strains, performed using a Galleria mellonella infection model and crystal violet staining method, respectively. CR-AB isolates that induced high mortality in the G. mellonella infection model were subjected to genotyping, susceptibility testing, and clinical data analysis, and the genetic characterization of these isolates was performed by whole-genome sequencing (WGS). Among the 109 CR-AB clinical strains, the survival rate of G. mellonella larvae infected with 7 (6.4%) CR-AB isolates (number of strains with mortality of 0, 10 and 20% was 4, 1, and 2, respectively), was significantly lower than that of A. baumannii ATCC 19606 (100.0%) and the remaining CR-AB isolates (> 80.0%). Consistent with these results, patients infected with these seven isolates had an average 7-day mortality rate of 42.9%, suggesting that the isolates were CR-hvAB. These seven isolates belonged to four sequence types (STs): ST457, ST195, ST369, and ST2088 (a new ST), and mainly ST457 (n = 4). The results of the biofilm study showed that eight strains had powerful biofilm ability (strong [n = 1] and moderate [n = 7] biofilm producers) including these seven CR-hvAB isolates. CONCLUSIONS: CR-hvAB isolates that induced a high mortality rate were cloned in our hospital, most of which belonged to ST457; thus, monitoring of these strains, particularly ST457, should be strengthened in the future. Meanwhile, A. baumannii, which was isolated from blood specimens and found to powerful biofilm-forming ability, is a probable hvAB isolate.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Acinetobacter baumannii/patogenicidade , Carbapenêmicos/farmacologia , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/etiologia , Acinetobacter baumannii/isolamento & purificação , Adolescente , Adulto , Idoso , Animais , Antibacterianos/farmacologia , Biofilmes , Criança , China , Modelos Animais de Doenças , Farmacorresistência Bacteriana/genética , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mariposas/microbiologia , Filogenia , Virulência/genética , Adulto Jovem
11.
J Cancer ; 11(15): 4614-4624, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32489479

RESUMO

Platelet-derived growth receptor α (PDGFRα) is a key factor in many pathophysiological processes. The expression level of PDGFRα is significantly elevated in the early stage of liver development and maintained at a lower level in adult normal livers. In this study, we constructed a liver-specific PDGFRαD842 mutant transgenic (TG) mice model to explore the effect of continuous activation of PDGFRα on liver regeneration and hepatocarcinogenesis. 14-day-old TG and wild-type (WT) mice were intraperitoneally injected with diethylnitrosamine (DEN) at a dose of 25 µg/g body weight. Two-month-old male TG and WT mice were subjected to partial hepatectomy (PH). The liver tissues were collected for further analysis at different time points. Overexpression of PDGFRα D842V and its target genes, Akt, c-myc and cyclin D1 in hepatocytes with no overt phenotype versus WT mice were compared. Unexpectedly, a dramatic decrease in hepatocyte proliferation was noted after PH in TG versus WT mice, possibly due to the downregulation of hepatocyte growth factor receptor (MET) and epidermal growth factor receptor (EGFR). No TG mice developed HCC spontaneously after 14 months follow-up. However, TG mice were more resistant to DEN-induced hapatocarcinogenesis at 6, 10, and 12 months of age, showing delayed hepatocyte proliferation and apoptosis, lower tumor incidence, smaller size and fewer number, compared with age-matched WTs, partially through downregulation of MET and EGFR. In conclusion, continuous activation of PDGFRα signaling by expression of PDGFRα D842V does not promote, but inhibit hepatic regeneration and hepatocarcinogenesis, possibly through compensatory downregulation of MET and EGFR.

12.
Infect Drug Resist ; 13: 703-710, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32184632

RESUMO

PURPOSE: Outbreaks of infection due to carbapenem-resistant Enterobacterales (CRE), including New Delhi metallo-ß-lactamase (NDM)-producing Escherichia coli, have been increasingly reported worldwide, primarily in adults and rarely in children. The goal of this study was to characterize an outbreak of infection caused by NDM-5-producing E. coli in a children's hospital in China. METHODS: A total of 86 CRE isolates were collected from 85 hospitalized children between June 2017 and May 2018. These isolates were subjected to multiple phenotypic and molecular tests, including in vitro antimicrobial susceptibility testing, PCR, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequencing (WGS). RESULTS: Among the 86 CRE isolates, we identified 9 NDM-5-producing E. coli isolates, with 5 of them sharing the same PFGE pattern, same MLST type (ST410), same plasmid replicon type (IncFII), and nearly the same set of additional resistance genes. All 9 isolates were resistant to most antimicrobial agents, including carbapenems, cephalosporins, and levofloxacin, while being sensitive to trimethoprim/sulfamethoxazole, amikacin, tigecycline, and colistin. According to the clinical background, all 9 isolates were collected in a period of < 3 months from infants among whom there was overlap in the time of hospitalization. None of them had a travel history. CONCLUSION: Our analysis suggests an outbreak of clonal dissemination, presumably due to nosocomial transmission. This study represents the first documented outbreak of NDM-5-producing E. coli mediated by IncFII in infants. Close monitoring is urgently needed to prevent and control the spread of this difficult-to-treat superbug.

13.
BMC Microbiol ; 19(1): 219, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31533609

RESUMO

BACKGROUND: The molecular characterization of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) isolates is not well studied. Our goal was to investigate the molecular epidemiology of CR-hvKP strains that were isolated from a Chinese hospital. RESULTS: All clinical carbapenem-resistant K. pneumoniae (CR-KP) isolates were collected and identified from patient samples between 2014 and 2017 from a Chinese hospital. The samples were subjected to screening for CR-hvKP by string test and the detection of the aerobactin gene. CR-hvKP isolates were further confirmed through neutrophil phagocytosis and a mice lethality assay. The CR-hvKP isolates were investigated for their capsular genotyping, virulence gene profiles, and the expression of carbapenemase genes by PCR and DNA sequencing. Multilocus sequence type (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to exclude the homology of these isolates. Twenty strains were identified as CR-hvKP. These strains were resistant to imipenem and several other antibiotics, however, most were susceptible to amikacin. Notably, two isolates were not susceptible to tigecycline. Capsular polysaccharide synthesis genotyping revealed that 17 of the 20 CR-hvKP strains belonged to the K2 serotype, while the others belonged to serotypes other than K1, K2, K5, K20, and K57. The strains were found to be positive for 10 types of virulence genes and a variety of these genes coexisted in the same strain. Two carbapenemase genes were identified: blaKPC-2 (13/20) and blaNDM-1 (1/20). PFGE typing revealed eight clusters comprising isolates that belonged to MLST types ST25, ST11 and ST375, respectively. PFGE cluster A was identified as the main cluster, which included 11 isolates that belong to ST25 and mainly from ICU department. CONCLUSIONS: Our findings suggest that hospital-acquired infections may contribute in part to the CR-hvKP strains identified in this study. It also suggests that ST25 CR-hvKP strain has a clonal distribution in our hospital. Therefore, effective surveillance and strict infection control strategies should be implemented to prevent outbreak by CR-hvKP strains in hospitals setting.


Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/patogenicidade , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Animais , Antibacterianos/farmacologia , Cápsulas Bacterianas/genética , Proteínas de Bactérias/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Carbapenêmicos/farmacologia , China/epidemiologia , Genótipo , Humanos , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Camundongos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Sorogrupo , Virulência/genética , beta-Lactamases/genética
14.
Chin Med J (Engl) ; 132(10): 1166-1172, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30882466

RESUMO

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) have been a challenging concern of health-care associated infections. The aim of the current study was to investigate the molecular epidemiology and clonal dissemination of CRAB isolates in a Chinese teaching hospital. METHODS: Non-duplicate clinical A. baumannii isolates were collected from inpatients, and we measured the minimal inhibitory concentrations to determine antimicrobial susceptibility. Polymerase chain reaction (PCR) and sequencing were performed to detect carbapenem-resistance genes and occurrence of transposons among CRAB isolates. Moreover, the genetic diversity among isolates and clonal dissemination were determined by repetitive element PCR-mediated DNA fingerprinting (rep-PCR) and multilocus sequence typing (MLST). RESULTS: A total of 67 CRAB isolates displayed resistance to most of the antibiotics tested in this study, except tigecycline. We detected blaOXA-23, blaOXA-51, blaOXA-58, and blaVIM genes in 94.0%, 100.0%, 1.5%, and 80.6% of the CRAB isolates, respectively. Nevertheless, 74.6% of the CRAB isolates co-harbored the blaOXA-23 and blaVIM. Only one type of transposons was detected: Tn2008 (79.1%, 53/67). Although 12 distinctive types (A-L) were determined (primarily A type) ST195 was the most prevalent sequence type (ST). ST368, ST210, ST90, ST829, and ST136 were also detected, and all belonged to clonal complex 208 (CC208) and global complex 2 (GC2). CONCLUSION: The blaOXA-23 and blaVIM genes contributed to the resistance among CRAB isolates collected in our study. Notably, most of the CRAB strains co-harbored blaOXA-23 and blaVIM genes, as well as Tn2008, which could contribute to clonal dissemination. The prevalence of such organisms may underlie hospital acquired infections.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Carbapenêmicos/farmacologia , beta-Lactamases/metabolismo , Proteínas de Bactérias/genética , Elementos de DNA Transponíveis/genética , Farmacorresistência Bacteriana Múltipla/genética , Genótipo , Hospitais de Ensino/estatística & dados numéricos , Humanos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase , beta-Lactamases/genética
15.
Chin Med J (Engl) ; 129(17): 2033-9, 2016 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-27569227

RESUMO

BACKGROUND: Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae bacteria, which cause serious disease outbreaks worldwide, was rarely detected in Xiangya Hospital, prior to an outbreak that occurred from August 4, 2014, to March 17, 2015. The aim of this study was to analyze the epidemiology and molecular characteristics of the K. pneumoniae strains isolated during the outbreak. METHODS: Nonduplicate carbapenem-resistant K. pneumoniae isolates were screened for blaKPC-2and multiple other resistance determinants using polymerase chain reaction. Subsequent studies included pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, analysis of plasmids, and genetic organization of blaKPC-2locus. RESULTS: Seventeen blaKPC-2-positive K. pneumoniae were identified. A wide range of resistant determinants was detected. Most isolates (88.2%) coharbored blaKPC-2and rmtB in addition to other resistance genes, including blaSHV-1, blaTEM-1, and aac(3)-IIa. The blaKPC-2and rmtB genes were located on the conjugative IncFIB-type plasmid. Genetic organization of blaKPC-2locusin most strains was consistent with that of the plasmid pKP048. Four types (A1, A2, A3, and B) were detected by PFGE, and Type A1, an ST11, was the predominant PFGE type. A novel K. pneumoniae sequence type (ST1883) related to ST11 was discovered. CONCLUSIONS: These isolates in our study appeared to be clonal and ST11 K. pneumoniae was the predominant clone attributed to the outbreak. Coharbing of blaKPC-2and rmtB, which were located on a transferable plasmid, in clinical K. pneumoniae isolates may lead to the emergence of a new pattern of drug resistance.


Assuntos
Proteínas de Bactérias/metabolismo , Infecções por Klebsiella/etiologia , Klebsiella pneumoniae/metabolismo , Metiltransferases/metabolismo , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , China , Eletroforese em Gel de Campo Pulsado , Hospitais de Ensino , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus
16.
Sci Rep ; 4: 6718, 2014 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-25342226

RESUMO

The expression levels of microRNAs (miRNAs) including miR-21, have been reported to change in response to traumatic brain injury (TBI), suggesting that they may influence the pathophysiological process in brain injury. To analyze the potential effect of miR-21 on neurological function after TBI, we employed the fluid percussion injury rat model and manipulated the expression level of miR-21 in brain using intracerebroventricular infusion of miR-21 agomir or antagomir. We found that upregulation of miR-21 level in brain conferred a better neurological outcome after TBI by improving long-term neurological function, alleviating brain edema and decreasing lesion volume. To further investigate the mechanism underlying this protective effect, we evaluated the impact of miR-21 on apoptosis and angiogenesis in brain after TBI. We found that miR-21 inhibited apoptosis and promoted angiogenesis through regulating the expression of apoptosis- and angiogenesis-related molecules. In addition, the expression of PTEN, a miR-21 target gene, was inhibited and Akt signaling was activated in the procedure. Taken together, these data indicate that miR-21 could be a potential therapeutic target for interventions after TBI.


Assuntos
Lesões Encefálicas/genética , MicroRNAs/genética , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Astrócitos/metabolismo , Lesões Encefálicas/metabolismo , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Modelos Animais de Doenças , Expressão Gênica , Imuno-Histoquímica , Masculino , MicroRNAs/metabolismo , Microglia/metabolismo , Neovascularização Fisiológica/genética , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Transdução de Sinais
17.
Asian Pac J Cancer Prev ; 14(3): 1743-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23679267

RESUMO

BACKGROUND AND PURPOSE: Cardiac myxoma is a major primary heart tumor which often causes unexpected symptoms or sudden death. This present study was designed to investigate its clinical pathological features and biological behavior. METHODS: A retrospective analysis of the clinical pathologic and immunohistochemical features of 66 cases with cardiac myxoma was conducted. RESULTS: In 66 patients with cardiac myxoma, 61 cases had involvement of the left atrium, one case in both the right ventricular and left atria. The female: male ratio was 2.7:1. Patients had symptoms of blood flow obstruction and systemic alterations with performance of arterial embolization. Tumors were spherical, lobulated or irregular in shape, and soft and brittle. Immunohistochemical markers of vimentin and CD34 in tumor cells were positive. CONCLUSION: Cardiac myxoma always exists in the left atrium and is more common in women, with diverse clinical manifestations and pathomorphism. Although proliferative activity and the recurrence rate are low, in addition to thorough surgical resection, strengthened review is important for young patients.


Assuntos
Átrios do Coração/patologia , Neoplasias Cardíacas/patologia , Ventrículos do Coração/patologia , Mixoma/patologia , Recidiva Local de Neoplasia/patologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Seguimentos , Átrios do Coração/metabolismo , Átrios do Coração/cirurgia , Neoplasias Cardíacas/metabolismo , Neoplasias Cardíacas/cirurgia , Ventrículos do Coração/metabolismo , Ventrículos do Coração/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Mixoma/metabolismo , Mixoma/cirurgia , Gradação de Tumores , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/cirurgia , Prognóstico , Estudos Retrospectivos , Adulto Jovem
18.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 26(10): 980-3, 2010 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-20937234

RESUMO

AIM: to observe whether the donor's marrow (BM) cells treated by GM-CSF and TGF-ß in vitro were beneficial in inducing specific hypoergia to donor's lymphocyte in recipient. METHODS: donor's marrow cell were cultured with GM-CSF and TGF-ß in vitro and its maturities were tested by treating with LPS. BALB/c mice were divided into three groups and received treatment as following: (1) BM pretreatment group: donor's BM cell mentioned above were injected into caudal vein with 10(5); cell each mouse; (2) donor's splenocyte group: C57BL/6 mouse's splenocyte were injected through caudal vein with 10(5); cell each mouse; (3) Negative control group: PBS with the same volume were injected through caudal vein. The treatment were performed twice with one week internal in each group. One week after the second treatment, all of the mice were challenged by splenocyte of C57BL/6 mouse in abdominal cavity with 10(5); cell each mouse. Three days later, the allo-reactivities were tested: the proliferation of recipient mouse lymphocyte to donor's lymphocyte were test by single mix lymphocyte reaction, the level of serum IFN-γ and IL-10 were tested with ELISA methods. CD4(+);CD25(high); Treg cell and expression of killer cell lectin-like receptor G1 (KLRG1) on NK cell were tested with flow cytometric technique and the NK cytotoxicity were measured by LDH release method. RESULTS: the donor's marrow cell treated by GM-CSF and TGF-ß in vitro could resist the maturation promotion by LPS. Compared with donor's lymphocyte pretreatment, pre-treatment with BM cell induced decreased IL-10, increased CD4(+);CD25(high); Treg cell in spleen, decreased proliferation to donor's lymphocyte in vitro. Additionally, NK cell cytotoxicity was also decreased. CONCLUSION: the donor's marrow cell treated by GM-CSF and TGF-ßcan induce the donor specific tolerance in some degree, and modulation of NK cell maybe participate in inducing immunological tolerance.


Assuntos
Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Tolerância Imunológica/efeitos dos fármacos , Fator de Crescimento Transformador beta/farmacologia , Animais , Ensaio de Imunoadsorção Enzimática , Feminino , Tolerância Imunológica/imunologia , Interferon gama/metabolismo , Interleucina-10/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Distribuição Aleatória , Doadores de Tecidos
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