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Numerical simulation and experimental investigation of laser-MIG hybrid angle-welding low-carbon 1.5-mm-thin SPCC steel sheets are presented in this work. The transient simulation analysis provides an access to the thermal-fluid phenomena prediction by employing a hybrid three-dimensional heat source model. Special attention is paid to the melt dynamic behaviors within the triangular molten pool affected by the Marangoni convection. The simulation results show that the temperature and its gradient distribution are symmetrical with respect to the laser beam, which is validated well by the experimental study. The microstructure of the welded joints was analyzed by scanning electron microscopy and transmission electron microscopy. The results show that the cross-section microstructures of welded joint are mainly composed of the weld zone, narrow heat-affected zone, and substrate. The semielliptic-like molten pool shape is consistent with that of the simulated results. The finer microstructure in the weld bead results from the rapid cooling rate of laser welding confirmed by the FEM calculation. The columnar and equiaxed dendrites are formed in the peripheral and central region of the molten pool, which is beneficial for the improvement of the microhardness.
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Ni35 thin coatings were prepared on 40Cr steel by preset powder laser cladding technology. The effects of powder size and preset thickness on the dilution rate, microstructure, and properties of the coating were systematically studied. The results showed that the coating with smaller powder size and larger preset thickness had smaller grain size, denser microstructure, a flatter bottom of the molten pool, and lower dilution rate. The micro-hardness of the coating with large powder size and preset thickness was higher. The friction coefficient of the coating with small powder size and small preset thickness was smaller, but the latter had larger curve fluctuation and wear volume loss. The corrosion rate of the coating was high during the first 24 h, then relatively stable after 68 h, and the corrosion rate and loss of the coating with small powder size and large preset thickness were smaller.
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AIMS: The aim of this study was to determine the effects of unsaturated fatty acids on clinical plasmids. METHODS AND RESULTS: Two unsaturated fatty acids, linoleic acid (LA) and α-linolenic acid (ALA) at final concentration 0, 0·03, 0·3 and 3 mmol l-1 , respectively, were used to assess the effects on conjugative transfer of a mcr-1-harbouring plasmid pCSZ4 (IncX4) in conjugation experiment. The inhibitory mechanisms were analysed by molecular docking and the gene expression of virB11 was quantitated by qRT-PCR. Target plasmid diversity was carried out by TrwD/VirB11 homology protein sequence prediction analysis. Our results showed that LA and ALA inhibit plasmid pCSZ4 transfer by binding to the amino acid residues (Phe124 and Thr125) of VirB11 with dose-dependent effects. The expression levels of virB11 gene were also significantly inhibited by LA and ALA treatment. Protein homology analysis revealed a wide distribution of TrwD/VirB11-like genes among over 37 classes of plasmids originated from both Gram-negative and Gram-positive bacteria. CONCLUSIONS: This study demonstrates representing a diversity of plasmids that may be potentially inhibited by unsaturated fatty acids. SIGNIFICANCE AND IMPACT OF THE STUDY: Our work reported here provides additional support for application of curbing the spread of multiple plasmids by unsaturated fatty acids.
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Escherichia coli/genética , Transferência Genética Horizontal/efeitos dos fármacos , Ácido Linoleico/farmacologia , Ácido alfa-Linolênico/farmacologia , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Colistina/farmacologia , Conjugação Genética , Farmacorresistência Bacteriana , Escherichia coli/classificação , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Expressão Gênica/efeitos dos fármacos , Ácido Linoleico/química , Ácido Linoleico/metabolismo , Simulação de Acoplamento Molecular , Plasmídeos/genética , Ácido alfa-Linolênico/química , Ácido alfa-Linolênico/metabolismoRESUMO
The microstructure and wear behavior of AISI 304 stainless steel after Nd:YAG pulsed laser surface melting (LSM) were investigated. The microstructural features of the LSM layer were characterized by field emission scanning electron microscope and high-resolution transmission electron microscope. Experimental results showed that the microstructure was obviously refined to the nano- and sub-micrometer scales on the AISI 304 stainless steel surface after LSM treatment. Fine grains with grain size of less than 200 nm were obtained when the applied laser energy densities were in the range of 1.90×107 to 3.52×107J/m2 during LSM. The results indicated that the calculated surface temperature, cooling rate, and measured grain size are closely related to the adopted laser energy densities. The lower the laser energy density is, the lower the surface temperature, and the faster the cooling rate, the finer the grain size. In addition, the microhardness and wear resistance of the stainless steel was significantly improved. Finally, the wear mechanism after LSM process was revealed.
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Objective: To analyze the impact of different admission ways on the timeliness of percutaneous coronary intervention and in-hospital mortality in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: A total of 1 044 patients with STEMI, who received primary percutaneous coronary intervention (PPCI) in 9 hospitals in Chengdu from January 2017 to June 2019, were retrospectively enrolled. According to the admission ways, patients were divided into ambulance group (n=100), self-transport group (n=584) and transferred group (n=360). Timeliness and in-hospital mortality were compared among the groups. Indicators of timeliness included the time from symptoms onset to arrive at the hospital, the time from arrive at the hospital to balloon and the total myocardial ischemia time (the time from symptoms to balloon). Multivariate logistic regression analysis was used to verify whether the admission ways was the determinant for in-hospital death in STEMI patients receiving PPCI. Results: The median total myocardial ischemic time in the ambulance group was significantly shorter than that in the self-transport group (180.0 (135.0, 282.0) minutes vs. 278.0 (177.8, 478.5) minutes, P<0.05) and the transferred group (180.0 (135.0, 282.0) minutes vs. 301.0 (204.3, 520.8) minutes, P<0.05). The median time from symptoms to door was as follows: ambulance group
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Intervenção Coronária Percutânea , Infarto do Miocárdio com Supradesnível do Segmento ST , Humanos , Estudos Retrospectivos , Fatores de Tempo , Resultado do TratamentoRESUMO
OBJECTIVE: Breast cancer (BC) is one of the most ordinary fatal cancers. Recent studies have identified the vital role of genes in the development and progression of Tri-negative breast cancer (TNBC). In this research, DGCR8 was studied to identify how it functioned in the metastasis of TNBC. PATIENTS AND METHODS: DGCR8 expression of tissues was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) in 50 TNBC patients. Wound healing assay and transwell assay were used to observe the changes in the biological behaviors of TNBC cells through knockdown or overexpression of DGCR8. In addition, qRT-PCR and Western blot assay were performed to discover the potential target protein of DGCR8 in TNBC. RESULTS: DGCR8 expression level in TNBC samples was higher than that of adjacent ones. Besides, the migration ability and invasion ability of TNBC cells were inhibited after DGCR8 was silenced, while they were promoted after DGCR8 was overexpressed. In addition, TGF-ß was downregulated after silencing of DGCR8 in TNBC cells, while TGF-ß was upregulated after overexpression of DGCR8 in TNBC cells. Furthermore, TGF-ß was upregulated in TNBC tissues, which was positively associated with DGCR8. CONCLUSIONS: Our study uncovers a new oncogene in TNBC and suggests that DGCR8 can enhance TNBC cell migration and invasion via targeting TGF-ß, which provides a novel therapeutic target for TNBC patients.
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Proteínas de Ligação a RNA/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Células Cultivadas , Epigênese Genética/genética , Humanos , Proteínas de Ligação a RNA/genética , Fator de Crescimento Transformador beta/genética , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
Mutations in the ectodysplasin A gene ( EDA) cause X-LHED (X-linked hypohidrotic ectodermal dysplasia), the most common human form of ectodermal dysplasia. Defective EDA signaling is linked to hypoplastic development of epithelial tissues, resulting in hypotrichosis, hypodontia, hypohidrosis, and xerostomia. The primary objective of the present study was to better understand the salivary gland dysfunction associated with ectodermal dysplasia using the analogous murine disorder. The salivary flow rate and ion composition of the 3 major salivary glands were determined in adult Eda-deficient Tabby hemizygous male (Ta/Y) and heterozygous female (Ta/X) mice. Submandibular and sublingual glands of Eda-mutant mice were smaller than wild-type littermates, while parotid gland weight was not significantly altered. Fluid secretion by the 3 major salivary glands was essentially unchanged, but the decrease in submandibular gland size was associated with a dramatic loss of ducts in Ta/Y and Ta/X mice. Reabsorption of Na+ and Cl-, previously linked in salivary glands to Scnn1 Na+ channels and Cftr Cl- channels, respectively, was markedly reduced at high flow rates in the ex vivo submandibular glands of Ta/Y mice (~60%) and, to a lesser extent, Ta/X mice (Na+ by 14%). Consistent with decreased Na+ reabsorption in Ta/Y mice, quantitative polymerase chain reaction analysis detected decreased mRNA expression for Scnn1b and Scnn1g, genes encoding the ß and γ subunits, respectively. Moreover, the Na+ channel blocker amiloride significantly inhibited Na+ and Cl- reabsorption by wild-type male submandibular glands to levels comparable to those observed in Ta/Y mice. In summary, fluid secretion was intact in the salivary glands of Eda-deficient mice but displayed marked Na+ and Cl- reabsorption defects that correlated with the loss of duct cells and decreased Scnn1 Na+ channel expression. These results provide a likely mechanism for the elevated NaCl concentration observed in the saliva of affected male and female patients with X-LHED.
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Displasia Ectodérmica Anidrótica Tipo 1/genética , Ectodisplasinas/genética , Glândulas Salivares/metabolismo , Cloreto de Sódio/metabolismo , Animais , Displasia Ectodérmica Anidrótica Tipo 1/metabolismo , Ectodisplasinas/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Tamanho do Órgão , Reação em Cadeia da Polimerase , Salivação/genética , Canais de Sódio/metabolismo , Glândula Submandibular/metabolismoRESUMO
It is a great challenge to improve the strength of disc superalloys without great loss of plasticity together since the microstructures benefiting the strength always do not avail the plasticity. Interestingly, this study shows that the trade-off relationship between strength and plasticity can be broken through decreasing stacking fault energy (SFE) in newly developed Ni-Co based disc superalloys. Axial tensile tests in the temperature range of 25 to 725 °C were carried out in these alloys with Co content ranging from 5% to 23% (wt.%). It is found that the ultimate tensile strength (UTS) and uniform elongation (UE) are improved synchronously when microtwinning is activated by decreasing the SFE at 650 and 725 °C. In contrast, only UTS is improved when stacking fault (SF) dominates the plastic deformation at 25 and 400 °C. These results may be helpful for designing advanced disc superalloys with relatively excellent strength and plasticity simultaneously.
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OBJECTIVE: Positive effects of bioactive glass (BG) on proliferation, mineralization, and differentiation of human dental pulp cells (hDPCs) was already verified in various former studies. The Arg-Gly-Asp-Ser sequence (RGDS) was confirmed of affecting cell adhesion. Before further investigation, the objective of this study is to investigate whether RGDS can affect the effects of BG on the adhesion, proliferation and mineralization of hDPCs. METHODS: hDPCs were harvested from third molars of 18-25-year-old individuals after informed consent. Enzyme digestion technique was used. The 4th to 6th generation of hDPCs were used for all experiments. The cells of the experimental groups were cultured in Dulbecco minimum essential medium (DMEM) containing ionic dissolution products of BG and RGDS of several concentrations (12.5 mg/L, 25.0 mg/L, 50.0 mg/L, 100.0 mg/L, 200.0 mg/L). DMEM containing ionic dissolution products of BG without RGDS was used for cell culture as control group. Cell adhesion was tested 4 h after cell seeding by MTT assay. Cell proliferation was examined at 1, 3, 5, 7, and 9 d after cell seeding by MTT assay. Cell mineralization was investigated on days 14 and 28 by alizarin red staining. After being stained and dried, mineralized nodules were dissolved by cetylpyridinium chloride (CPC) for semi-quantitative test. Results were statistically analyzed by one way ANOVA, SPSS (version 19.0) and P<0.05 was considered to be significant. RESULTS: Cell adhesion in BG group showed no difference from that in DMEM group. Compared with BG group, hDPCs in BG+RGDS groups suggested weaker cell adhesion.When the concentration of RGDS increased, the adhered cell number decreased. hDPCs cultured with BG and RGDS showed lower proliferation activity in the early stage, while no significant difference was observed after 3 d. BG group promoted the mineralization of hDPCs compared with positive control group, negative control group and RGDS group. No significant difference was observed between BG+RGDS group and BG group or between RGDS group and positive control group. CONCLUSION: BG promotes proliferation and mineralization without affecting cell adhesion of hDPCs. Unbounded RGDS inhibits cell adhesion, but has no influence on the positive effects of BG on the proliferation and mineralization of hDPCs.
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Diferenciação Celular , Proliferação de Células , Células Cultivadas , Polpa Dentária , Oligopeptídeos , Antraquinonas , Adesão Celular , Técnicas de Cultura de Células , Células Epiteliais , Vidro , HumanosRESUMO
OBJECTIVE: To investigate the proliferation, odontogenic differentiation and mineralization of human dental pulp cells (HDPCs) on bioactive glass(BG) and extracted dentin proteins(EDP). METHODS: Primary HDPCs were isolated from third molars by enzyme digestion and were cultured in Dulbecco's minimum essential medium (DMEM). Then the 4th generation of HDPCs was cultured with DMEM, which contained BG-EDP, BG, and EDP, respectively. Meanwhile HDPCs were cultured in DMEM as control group. Proliferation of HDPCs was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) colorimetric assay. Odontogenic differentiation was determined by alkaline phosphatase (ALP) activity assay and real-time PCR. Mineralization was investigated by Alizarin red staining and cetylpyridinium chloride (CPC) assay. RESULTS: The proliferation of HDPCs was increased significantly in BG-EDP group on 3,7,and 9 d (optical density value: 1.36±0.06, 2.52±0.20, 2.72±0.29) compared with BG (optical density value: 1.20±0.26, 2.33±0.26, 2.50±0.30), EDP(optical density value: 1.13±0.15, 2.10±0.13, 2.38±0.22) and control group (optical density value: 0.84±0.17, 1.84±0.18, 1.95±0.19), P<0.05. After 7 days, ALP activity of BG-EDP group had no statistical difference compared with EDP group and control group; the expression of odontogenic differentiation genes (DSPP, DMP-1) showed no difference among all the groups(P>0.05). After 14 days, ALP activity of BG-EDP group (56.67±1.83) was significantly upregulated compared with EDP group (41.98±9.71) and control group (30.82±6.70), P<0.05, but had no statistical difference compared with BG group (56.29±6.20), P>0.05; DSPP gene expression was upregulated significantly in BG-EDP group (5.79±1.94) compared with the other groups (P<0.05); DMP-1 gene expression of BG-EDP group (3.87±1.87) increased but had no statistical difference compared with the other groups (P>0.05). The alizarin red staining showed more mineral nodules in BG-EDP group, the cetylpyridinium chloride semi-quantification presented higher calcification in BG-EDP group (0.27±0.01) compared with the other groups (P<0.05). CONCLUSION: Compared with either BG or EDP, BG-EDP significantly promotes the proliferation, odontogenic differentiation and mineralization of HDPCs.
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Proliferação de Células , Polpa Dentária , Dentina/metabolismo , Odontogênese , Fosfatase Alcalina , Antraquinonas , Diferenciação Celular , Células Cultivadas , Células Epiteliais , Proteínas da Matriz Extracelular/metabolismo , Vidro , Humanos , Fosfoproteínas/metabolismoRESUMO
OBJECTIVE: Discuss the main points of diagnosis of cortriatrium; patient's color Doppler echocardiography (CDE), provide basis for clinical treatment. PATIENTS AND METHODS: Inspect 12 cortriatrium cases with CDE, 10 cases with cardiovascular angiography, 12 patients were confirmed by operation. Operations were all carried out under the moderate hypothermia cardiopulmonary bypass with intracardiac correction technique. Abnormal diaphragm in the left a trial was completely removed, and other combined heart malformations were also cured. RESULTS: Four cases for II A type, 1 case for II B type, 6 cases for II A type, 1 case for II B type. Among them, there were 7 cases for combined atrial septal defect, 5 cases for ventricular septal defect, 3 cases for patent ductus arteriosus, 6 cases for pulmonary arterial hypertension. Twelve children all survived, deformity correction was satisfactory, and after operation, recovery went on well in 6 months to 3 years. CONCLUSIONS: CDE has specific diagnostic value for cortriatrium; thus, it is the optimal method of diagnosing cortriatrium.
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Ponte Cardiopulmonar/métodos , Ecocardiografia Doppler/métodos , Cardiopatias Congênitas/diagnóstico , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , MasculinoRESUMO
OBJECTIVE: To explore changes of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) level in children having undergone radical operation of tetralogy of Fallot (TOF) and its clinical significance. PATIENTS AND METHODS: 52 cases of children with TOF hospitalized in our hospital from October 2011 to April 2013 were chosen, and they were all treated with radical operation of TOF. Levels of plasma NT-proBNP in these children were measured before the operation, and 3h, 12h, 48h, 1 week, 1 months, and 3 months after the operation. The cardiac color supersonic diagnostic set was used to examine pulmonary artery transvalvular pressure gradient, right ventricular end-diastolic volume (RVEDV), left ventricular ejection fraction (LVEF), and right ventricular Tei index. RESULTS: (1) 3h after the operation, the level of NT-proBNP gradually rose and reached its peak 48h after the operation, which was markedly higher than the level before the operation (p < 0.01), yet the levels measured 1 month and 3 months after the operation were lower than the level before the operation (p < 0.05). (2) 1 week after the operation, NT-proBNP level, pulmonary artery transvalvular pressure gradient, and RVEDV of the group with right ventricular dysfunction were markedly higher than those of the group with normal right ventricular function (p < 0.05). (3) 3 months after the operation, levels of plasma NT-proBNP of children in the severe reflux group and moderate reflux group were markedly higher than those in the slight reflux group (p < 0.05); levels of plasma NT-proBNP of children in the severe reflux group were markedly higher than those of the slight reflux group (p < 0.05) 1 week or 3 months after the operation. CONCLUSIONS: Changes of the NT-proBNP level during early stage after radical operation of children's TOF were in line with changes of the right ventricular function and could be regarded as an objective indicator for evaluating the right ventricular function.
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Peptídeo Natriurético Encefálico/sangue , Tetralogia de Fallot/sangue , Tetralogia de Fallot/cirurgia , Biomarcadores/sangue , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Tetralogia de Fallot/diagnóstico por imagem , Tetralogia de Fallot/fisiopatologia , UltrassonografiaRESUMO
The microstructures of a new Ni-Co-base disc superalloy, TMW-4M3, before and after the creep test at 725 °C/630 MPa have been systematically investigated by transmission electron microscopy (TEM). The crept microstructures were marked as three different deformation stages (I, II and III) corresponding to the gradually increased strain. At stage I, stacking fault (SF) shearing was the main deformation mechanism. The SF was extrinsic and lay on {111} plane. However, deformation microtwinning became the dominant mode at stage II and III. The average spacing of deformation twins decreased from 109 ± 15 nm at stage II to 76 ± 12 nm at stage III, whereas the twin thickness did not change significantly. The influence of stacking fault energy (SFE) of γ matrix on the deformation mechanism is discussed. It is suggested that lower SFE in TMW-4M3 is partly responsible for the enhanced creep resistance.
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The microstructure of a newly developed Co-base superalloy with enhanced high-temperature strength has been investigated using transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP) techniques. It mainly consists of a typical gamma/gamma' (FCC/L1(2)) structure and a plate-shaped AB3-type (Ni,Co,Cr)3(Ti,Al) intermetallic compound with hexagonal structure (a approximately 5.1A and c approximately 12.5A). gamma' is formed with a bimodal distribution and fine gamma' has a cuboidal morphology. Cr and Co are enriched in the gamma phase, while Ti, Al and Ni are enriched in the gamma' phase. W and Mo are more or less uniformly distributed in both gamma and gamma'. Chemical composition analysis by 3DAP suggests that the plate-shaped phase has a higher Ti and lower Al content compared to that of gamma' phase, and the concentration of Ti, Co and Ni has a periodic variation along c-axis with a period of 12.5A in the plate-shaped phase.
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Mutations in the human ectodysplasin-A (EDA) are responsible for the most common form of the ectodermal dysplasia and the defective orthologous gene in mice produces the tabby phenotype, suggesting its vital role in the development of hair, sweat glands and teeth. Among several EDA splice isoforms, the most common and the longest EDA splice isoforms, EDA-A1 and EDA-A2, differing by only two amino acids, activate NF-kappaB-promoted transcription by binding to distinct receptors, EDAR and XEDAR. The extent to which any particular isoform is sufficient for the formation of hair, sweat glands or teeth has remained unclear. Here we report that transgenic expression of the mouse EDA-A1 isoform in tabby (EDA-less) males rescued development of several skin appendages. The transgenic tabby mice showed almost complete restoration of hair growth, dermal ridges, sweat glands and molars. The number of hair follicles in the transgenic mice is the same as in wild-type; though the development of follicles and associated glands varies from indistinguishable from wild-type to smaller and/or only partially formed. These results suggest that the other EDA isoforms may not be absolutely required for skin appendage formation, but consistent with distinctive temporal and spatial expression of the EDA-A2 isoform, are likely required for appropriate timing and completeness of development. Our data provide the first direct physiological evidence that EDA-A1 is a key regulator of hair follicle and sweat gland initiation; its soluble ligand form could aid in deriving therapeutic reagents for conditions affecting hair and sweat gland formation.
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Cabelo/crescimento & desenvolvimento , Proteínas de Membrana/fisiologia , Glândulas Sudoríparas/fisiologia , Animais , Ectodisplasinas , Feminino , Cabelo/fisiologia , Humanos , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Estrutura Terciária de Proteína , Anormalidades da Pele , Glândulas Sudoríparas/crescimento & desenvolvimento , Cauda , Dente/crescimento & desenvolvimento , Anormalidades DentáriasRESUMO
We performed immunohistochemical, ultrastructural, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL), and DNA ladder studies of apoptosis in nine cases of Merkel cell carcinoma (MCC). None of the cases showed spontaneous regression as has been reported in several MCCs. Neuron-specific enolase was demonstrated by immunohistochemistry (8/8 MCCs), and staining for cytokeratin 20 was positive (2/8 MCCs). Ultrastructural examination revealed many cytoplasmic dense-cored granules, desmosome-like structures, and intermediate filaments. The granules were seen along the plasma membrane or around perinuclear centrioles. We found various stages of development of apoptotic bodies. Apoptosis resulted in vacuolization and fragmentation of nuclei and phagocytosed bodies in tumor cells. Apoptotic cells were also detected by TUNEL, DNA ladder, and immunostaining using the antibody against Fas (Apo- 1/CD95) antigen. It seems that a high apoptotic rate is a common finding in MCC, although spontaneous regression is an exceedingly rare event. It is thus unlikely that apoptosis alone would explain spontaneous regression.
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Apoptose , Carcinoma de Célula de Merkel/patologia , Neoplasias Cutâneas/patologia , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Célula de Merkel/química , Carcinoma de Célula de Merkel/genética , Contagem de Células , Estruturas Citoplasmáticas/ultraestrutura , Fragmentação do DNA , DNA de Neoplasias/análise , Desmossomos/ultraestrutura , Eletroforese em Gel de Ágar , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Marcação In Situ das Extremidades Cortadas , Proteínas de Filamentos Intermediários/análise , Queratina-20 , Masculino , Fosfopiruvato Hidratase/análise , Neoplasias Cutâneas/química , Neoplasias Cutâneas/genética , Receptor fas/análiseRESUMO
Interaction of CD95 ligand with its cognate receptor CD95 induces apoptotic cell death. Alterations in this pathway within tumor cells can result in escape from apoptosis and from immune surveillance. Melanoma cells recently were found to escape an immune attack via high expression of CD95 ligand, thereby inducing apoptosis of activated T lymphocytes. When screening four human melanoma cell lines for expression of CD95 and CD95 ligand, respectively, an inverse correlation was found, i.e., cells expressing high levels for CD95 ligand (CD95L(high)) were almost negative for CD95 and vice versa. Since coexpression of CD95 and CD95 ligand may lead to apoptosis by autocrine suicide or fratricide, it was tested whether overexpression of CD95 in CD95L(high) melanoma cells results in apoptotic cell death. Upon transfection with a cytomegalovirus-promoter-driven expression vector encoding the CD95 gene, CD95L(high) melanoma cells underwent apoptosis at a much higher level than CD95L(low) melanoma cells. Apoptosis appeared to be due to the activation of CD95 as cell death was inhibited by cotransfection with a dominant negative mutant for the CD95 signaling protein, Fas-associated protein with death domain. Tumor progression of CD95L(high) melanoma cells transplanted into nude mice was significantly reduced when recipient animals were injected with liposomes containing the CD95 expression vector. As demonstrated by immunohistochemistry and TUNEL staining, in vivo transfected tumor cells expressed CD95 and underwent apoptotic cell death. Hence, this study indicates that delivery of the CD95 gene inhibits tumor growth in vivo and thus might be a therapeutic strategy to treat tumor cells that express high levels of CD95 ligand. J Invest Dermatol 115:1008-1014 2000
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Proteínas de Arabidopsis , Melanoma/patologia , Receptor fas/farmacologia , Apoptose/imunologia , Divisão Celular/efeitos dos fármacos , Ácidos Graxos Dessaturases/genética , Técnicas de Transferência de Genes , Humanos , Mutação , Transfecção , Células Tumorais Cultivadas , Receptor fas/genéticaRESUMO
Bikunin, which is an inhibitor of serine proteases, is widely distributed in human tissues, including liver, kidney, and mucous membranes of the stomach and colon. The aim of this study was to clarify whether bikunin is expressed in human epidermis and its appendages. Immunoblot analysis using a specific polyclonal antibody to bikunin revealed that a single 43 kDa protein is present in the cell lysate from the human keratinocyte cell line HaCaT. Immunohistochemically, dotted reaction products stained with anti-bikunin antibody were localized on the cell boundary in both basal and spinous cell layers, except on the cell boundary of the basal cells facing the basal membrane. There were no reaction products in the granular-horny cell layers. Reaction products stained with anti-bikunin antibody were also observed on the hair bulb cells and eccrine sweat gland cells, but not on apocrine sweat glands. Also, reaction products were observed on the luminal surface of the renal proximal tubules and in the cytoplasm of these cells. In immunoelectron microscopy, gold particles were observed on the cell membranes close to the desmosomal structures. Reverse transcription-polymerase chain reaction and northern blot analyses showed that mRNA specific for bikunin was expressed in HaCaT cells and human epidermal keratinocytes obtained from suction blisters, and was contained in a commercially available human keratinocyte cDNA preparation. These findings indicate that bikunin is expressed in keratinocytes and may play an important part in regulating keratinocytes in either mitosis or inflammation.
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Células Epidérmicas , Epiderme/química , Glicoproteínas/análise , Glicoproteínas/imunologia , Glicoproteínas de Membrana , Inibidores de Serina Proteinase/análise , Inibidor da Tripsina de Soja de Kunitz , Anticorpos/análise , Linhagem Celular , Reações Cruzadas/imunologia , Glicoproteínas/genética , Folículo Piloso/imunologia , Humanos , Immunoblotting , Queratinócitos/imunologia , Queratinócitos/metabolismo , RNA Mensageiro/metabolismo , Glândulas Sudoríparas/imunologiaRESUMO
Because it has been suggested that the majority of the activity hydrolysing [N-methyl-14C] sphingomyelin is due to sphingomyelin acylase in the lesional skins of atopic dermatitis (AD), in this study we used immunologic techniques to localize and quantitate sphingomyelinase in AD lesional and normal skin. A polyclonal antibody raised against a synthetic polypeptide corresponding to a portion of the amino acid sequence deduced from the cDNA of human acid sphingomyelinase, cross-reacted with a 58 kDa, pI 5.8 human epidermal protein in an immunoblot analysis. The 58 kDa protein-rich fraction, partially purified by immunoprecipitation, converted [N-methyl-14C]-sphingomyelin to 14C-phosphorylcholine and ceramides. The reaction products were immunohistochemically observed in the intercellular domain from the upper spinous cell layer to the upper stratum corneum cell layers in the lesional skin of AD patients. Immunoelectron-microscopically, gold particles appeared to be concentrated in the intercellular domains of the granular-upper stratum corneum cells in the lesional skin of AD patients. The total amount of the 58 kDa protein in a 7 mm2 area of the skin was measured by quantitative immunoblot analysis; and was slightly increased in the lesional skin samples [3.5 +/- 0.3 microg per 7 mm2 (n = 7)], as compared with the nonlesional skin samples of AD patients [2.8 +/- 0.19 microg per 7 mm2 (n = 10)] and with the normal skin samples [2.7 +/- 0.22 microg per 7 mm2 (n = 10)]. This difference (between the lesional skin of AD and the nonlesional skin of AD or the normal control) was significant (nonpaired student's t test, p < 0.05).