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BACKGROUND: Occupational footwear is intended to provide protection against the risks associated with work activities. The choice of footwear is complex due to the welfare, health and safety conditions of workers. AIMS: To identify the injuries and problems caused by occupational footwear through a systematic review of the existing literature. METHODS: A literature search was carried out in the Cumulative Index to Nursing and Allied Health Literature, Dialnet Plus, Pubmed, Scientific Electronic Library Online, Medline, Scopus and Web of Science databases over the period 2000-23, following the PRISMA Declaration guidelines. RESULTS: A total of 27 studies were included in the review. The results indicated that there is a wide variety of injuries caused by occupational footwear: from dermal injuries (e.g. calluses) and injuries to the nail apparatus to inflammatory pathologies such as plantar fasciitis or bursitis. In addition, inappropriate footwear can cause pain in the ankle and foot, knees, hips and lower back. Other results include the discomfort derived from the footwear itself. CONCLUSIONS: Inappropriate footwear can cause injuries to the foot and other related bone structures. Further studies are needed on the detection of foot injuries caused by occupational footwear and the levels of action at this level to improve the worker's health, the adaptability of the footwear to the wearer, and the worker's comfort and adherence to the footwear.
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Traumatismos Ocupacionais , Sapatos , Humanos , Bursite/etiologia , Fasciíte Plantar/etiologia , Traumatismos do Pé/etiologia , Doenças Profissionais/etiologia , Traumatismos Ocupacionais/etiologia , Sapatos/efeitos adversosRESUMO
In this work, we develop experimentally a Fabry-Perot fiber optic interferometer applied to the measurement of autocorrelation of complex dynamic pulses generated by a figure-eight fiber laser. The principle is based in the superposition of multiple pulses, which requires two partially reflecting flat surfaces in parallel, resulting in a simple and compact autocorrelator design. The autocorrelation trace obtained exhibits a typical double-scaled structure for noise-like pulses (NLPs), with an ultrashort coherence spur on the order of 100 fs riding upon a broad pedestal of 120 ps. Finally, we show experimentally that the developed Fabry-Perot device is able to measure accurately the autocorrelation of NLPs, as confirmed by comparing the measurement with that of a conventional autocorrelator scheme based on a Michelson interferometer, with the additional advantages of a more compact setup and a much easier alignment procedure compared to the latter.
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COVID-19 pandemic created a global shortage of medical protective equipment. Here, we considered ozone (O3) a disinfectant alternative due to its potent oxidative activity against biological macromolecules. The O3 decontamination assays were done using SARS-CoV-2 obtained from patients to produce artificial contamination of N95 masks and biosecurity gowns. The quantification of SARS-CoV-2 was performed before and after exposing the samples to different ozone gas concentrations for times between 5 and 30 min. Viral loads as a function of the O3 exposure time were estimated from the data obtained by the RT-PCR technique. The genetic material of the virus was no longer detected for any tested concentrations after 15 min of O3 exposure, which means a disinfection Concentration-Time above 144 ppm min. Vibrational spectroscopies were used to follow the modifications of the polymeric fibers after the O3 treatment. The results indicate that the N95 masks could be safely reused after decontamination with treatments of 15 min at the established O3 doses for a maximum of 6 cycles.
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INTRODUCTION: Sex disparities exist in coronary artery disease (CAD) in terms of risk profile, clinical management and outcome. It is unclear if differences are also present in coronary aneurysms, a rare variant of CAD. METHODS: Patients were selected from the international Coronary Artery Aneurysm Registry (CAAR; ClinicalTrials.gov: NCT02563626), and differences between groups were analysed according to sex. The CAAR database is a prospective multicentre registry of 1565 patients with coronary aneurysms (336 females). Kaplan-Meier method was used for event-free survival analysis for death, major adverse cardiac events (MACE: composite endpoint of death, heart failure and acute coronary syndrome) and bleeding. RESULTS: Female patients were older, were more often hypertensive and less frequently smoker. They were treated conservatively more often compared to male patients and received significantly less frequently aspirin (92% vs 88%, pâ¯= 0.002) or dual antiplatelet therapy (DAPT) (67% vs 58%, pâ¯= 0.001) at discharge. Median DAPT duration was also shorter (3 vs 9 months, pâ¯= 0.001). Kaplan-Meier analysis revealed no sex differences in death, MACE or bleeding during a median follow-up duration of 37 months, although male patients did experience acute coronary syndrome (ACS) more often during follow-up (15% vs 10%, pâ¯= 0.015). CONCLUSIONS: These CAAR findings showed a comparable high-risk cardiovascular risk profile for both sexes. Female patients were treated conservatively more often and received DAPT less often at discharge, with a shorter DAPT duration. ACS was more prevalent among male patients; however, overall clinical outcome was not different between male and female patients during follow-up.
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A subset of patients with early gastric cancer demonstrate early recurrence and poor survival despite margin-negative resection. This study used an extremes-of-survivorship approach to identify an association between TP53 hotspot mutations co-occurring with loss of heterozygosity and unexpectedly poor survival in early gastric cancer. This distinct genomic profile may be a novel biomarker of poor survival in patients with completely resected early gastric cancer, and warrants large-scale validation. Promising, validation needed.
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Mutação/genética , Neoplasias Gástricas/cirurgia , Proteína Supressora de Tumor p53/genética , Idoso , Biomarcadores Tumorais/genética , Feminino , Marcadores Genéticos/genética , Genômica , Humanos , Perda de Heterozigosidade/genética , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/mortalidade , Neoplasias Gástricas/genética , Neoplasias Gástricas/mortalidade , Sequenciamento Completo do GenomaRESUMO
The long-term exposure of OF1 mice to an extremely low frequency magnetic field (ELF-MF; 50 Hz, 15 µT [rms]) has been associated with the appearance of leukaemia. Neoplasms are usually accompanied by changes in haemostatic processes but reports on changes in blood coagulation following exposure to an ELF-MF are scarce and rather fragmentary. The aim of the present work was to determine whether any global or partial coagulation variables are modified after such long-term exposure. A parental generation of six week-old OF1 mice was exposed to an artificial ELF-MF for 14 weeks. Mating was then allowed, and the resulting filial generation raised until the age of 31-35 weeks within the same ELF-MF. Control animals were subjected only to the magnetic field of the Earth. Whole blood samples were extracted from the anesthetised filial generation of mice by cardiac puncture. White blood cells (WBC) were counted, the activated partial thromboplastin time (APTT) and prothrombin time (PT) determined, and plasma fibrinogen, reptilase time (RT), and factor VIII activity examined. The similarity between the results for the present control animals and those recorded in the literature for human blood render OF1 mice a suitable study model. The differences in the studied coagulation variables were largely owed simply to sex. However, the females showed a very significant shortening of the PT time associated with ELF-MF exposure. Exposure also caused significant increases in the female APTT and RT values, and in general reduced the differences between the sexes.
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Coagulação Sanguínea , Campos Magnéticos/efeitos adversos , Animais , Feminino , Fibrinogênio/metabolismo , Masculino , Camundongos , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Fatores de TempoRESUMO
Mycoplasma ovis is a small, pleiotropic bacterium, which parasitizes the external surface of erythrocytes of several species of artiodactyl mammals, especially sheep and goats. We here report an outbreak of ovine mycoplasmosis in a sheep flock of a private ranch (Universidad Veracruzana) in Veracruz, Mexico. For the identification of Mycoplasma and other hemoparasitic bacterial agents, we stained blood smears with the DiffQuick® technique and additionally amplified several fragments of 16S rDNA gene. We detected the presence of morulas in erythrocytes from 30 sick female adult sheep, and found Mycoplasma ovis DNA in all of them. Furthermore, three of these animals also tested positive for Anaplasma ovis. Our findings represent the first record of M. ovis and A. ovis in an outbreak of hemolytic anemia in a sheep flock, leading to severe livestock loss in a ranch of Mexico. This study highlights the importance of establishing an active surveillance of both pathogens in the country.
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Anemia Hemolítica/veterinária , Infecções por Mycoplasma/veterinária , Mycoplasma/isolamento & purificação , Doenças dos Ovinos/microbiologia , Anaplasma ovis/isolamento & purificação , Anemia Hemolítica/epidemiologia , Anemia Hemolítica/microbiologia , Animais , Surtos de Doenças/veterinária , Eritrócitos , Feminino , Gado , México , Mycoplasma/genética , Infecções por Mycoplasma/epidemiologia , Ovinos , Doenças dos Ovinos/epidemiologiaRESUMO
Accumulation of bile acids can lead to invalidating pruritus in cholestatic patients. Few reports exist on the influence of lipoprotein-apheresis (LA) on plasma level of total bile acids (tBA). We report of significant decrease in tBA levels and drastic improvement of pruritus in a 5-year-old girl with arthrogryposis-renal failure-cholestasis syndrome. We present LA as a suitable rescue treatment option in therapy-refractory cholestasis-associated pruritus, at least as bridge until a long-term solution such as entero-biliary anastomosis or transplantation is possible.
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Ácidos e Sais Biliares/sangue , Remoção de Componentes Sanguíneos/métodos , Lipoproteínas/isolamento & purificação , Prurido/terapia , Artrogripose , Pré-Escolar , Colestase , Feminino , Humanos , Insuficiência Renal , Terapia de Salvação/métodos , SíndromeRESUMO
A molecularly imprinted polymer was developed and evaluated for selective determination of metronidazole (MNZ) in wastewater. This was achieved by using sodium methacrylate as monomer, toluene as porogen, ethylene glycol dimethacrylate as crosslinker, azobisisobutyronitrile as initiator and metronidazole as template molecule to generate the selectivity of the polymer for the compound, as well as non-imprinted polymers were synthesized. Two different polymerization approaches were used, bulk and emulsion and the polymers obtained by emulsion presented higher retention percentages the MIP 2-M presented the higher retention (83%). The performed method, was validated in fortified water, showing linearity from 10 up to 1000 ng/mL; limit of detection and quantification for compound were between 3 and 10 ng/mL, respectively. Finally, the method was applied in samples of a wastewater treatment plant in the city of San Luis Potosí, México, and the concentrations of MNZ in these samples were 84.1-114 ng/mL.
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Metronidazol/análise , Impressão Molecular/métodos , Ácidos Polimetacrílicos/síntese química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Adsorção , Limite de Detecção , Metacrilatos/química , México , Nitrilas/química , Ácidos Polimetacrílicos/química , Propriedades de Superfície , Tolueno/químicaRESUMO
OBJECTIVE: Functional assessment of coronary artery stenosis is performed by measuring the fractional flow reserve (FFR) under hyperemic conditions (Adenosine). However, the use of adenosine portends limitations. OBJECTIVE: We sought to investigate the relationship and correlation between FFR and the Pd/Pa value obtained just after the intracoronary infusion (acute drop) of nitroglycerin (Pd/Pa-NTG) and if this parameter enhances diagnostic accuracy for FFR prediction compared to the resting baseline Pd/Pa. METHODS: We conducted a multicenter study including prospectively patients presenting intermediate coronary artery stenosis (30-70%) evaluated with pressure wire. Resting baseline Pd/Pa, Pd/Pa-NTG and FFR were measured. RESULTS: 283 patients (335 lesions) were included. Resting baseline Pd/Pa value was 0.72 to 1.0 (0.93 ± 0.04), Pd/Pa-NTG was 0.60 to 1.0 (0.87 ± 0.07) and FFR 0.55 to 1.0 (0.83 ± 0.08). The ROC curves for resting baseline Pd/Pa and for Pd/Pa-NTG, using a FFR ≤ 0.80 showed an AUC of 0.88 (95% CI: 0.84-0.92, P < 0.001) and 0.94 (95% CI: 0.92-0.96, P < 0.001) respectively. The optimal cutoff values of resting baseline Pd/Pa and Pd/Pa-NTG for an FFR > 0.80, were >0.96 and >0.88, respectively. These values were present in a 29.8% (n = 100) and a 47.1% (n = 158), of the total lesions. Scatter plots showed a better correlation and agreement points with Pd/Pa-NTG than resting baseline Pd/Pa. The cutoff value of Pd/Pa-NTG > 0.88 showed an excellent NPV (96.2% for FFR > 0.8 and 100% for FFR > 0.75) and sensitivity (95% for FFR > 0.8 and 100% for FFR > 0.75) which were consistently high across all the subgroups analysis. CONCLUSION: The cutoff value of acute Pd/Pa-NTG > 0.88 has a high NPV meaning adenosine-FFR can be avoided in almost half of lesions.
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Adenosina/administração & dosagem , Pressão Arterial , Cateterismo Cardíaco , Estenose Coronária/diagnóstico , Vasos Coronários/fisiopatologia , Reserva Fracionada de Fluxo Miocárdico , Nitroglicerina/administração & dosagem , Vasodilatadores/administração & dosagem , Idoso , Área Sob a Curva , Velocidade do Fluxo Sanguíneo , Angiografia Coronária , Estenose Coronária/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Feminino , Humanos , Hiperemia/fisiopatologia , Infusões Intra-Arteriais , Masculino , Microcirculação , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Curva ROC , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Espanha , Procedimentos DesnecessáriosRESUMO
BACKGROUND: The value of a combined index of neutrophil and white cell counts, named derived neutrophil-lymphocyte ratio (dNLR), has recently been proposed as a prognosticator of survival in various cancer types. We investigated the prognostic role of the dNLR in a large European cohort of patients with upper tract urothelial carcinoma (UTUC). METHODS: Data from 171 non-metastatic UTUC patients, operated between 1990 and 2012 at a single tertiary academic centre, were evaluated retrospectively. Cancer-specific- (CSS) as well as overall survival (OS) were assessed using the Kaplan-Meier method. To evaluate the independent prognostic significance of the dNLR, multivariate proportional Cox-regression models were applied. Additionally, the influence of the dNLR on the predictive accuracy of the multivariate model was further determined by Harrell's concordance index (c-index). RESULTS: The median follow-up period was 31 months. An increased dNLR was statistically significantly associated with shorter CSS (log-rank P=0.004), as well as with shorter OS (log-rank P=0.002). Multivariate analysis identified dNLR as an independent predictor for CSS (hazard ratio, HR=1.16, 95% confidence interval, CI=1.01-1.35, P=0.045), as well as for OS (HR=1.21, 95% CI=1.09-1.34, P<0.001). The estimated c-index of the multivariate model for OS was 0.68 without dNLR and 0.73 when dNLR was added. CONCLUSIONS: Patients with a high pretreatment dNLR could be predicted to show subsequently higher cancer-specific- as well as overall mortality after surgery for UTUC compared with those with a low pretreatment dNLR. Thus, this combined index should be considered as a potential prognostic biomarker in future.
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Carcinoma de Células de Transição/sangue , Neoplasias Renais/sangue , Contagem de Leucócitos , Neutrófilos , Neoplasias Ureterais/sangue , Idoso , Áustria/epidemiologia , Carcinoma de Células de Transição/mortalidade , Fatores de Confusão Epidemiológicos , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Neoplasias Renais/mortalidade , Neoplasias Renais/cirurgia , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Necrose , Prognóstico , Modelos de Riscos Proporcionais , Curva ROC , Estudos Retrospectivos , Neoplasias Ureterais/mortalidade , Neoplasias Ureterais/cirurgiaRESUMO
Gastroesophageal reflux disease (GERD) has been related with certain psychological dimensions. The influence of mood, emotional intelligence, and perceived quality of life on clinical symptoms and outcome of antireflux surgery was evaluated in GERD patients with and without hiatal hernia. The study included 61 patients who were diagnosed with GERD between 2003 and 2008: 16 of them without hiatal hernia (group A) and 45 of them with hiatal hernia (group B). All of these patients had undergone laparoscopic antireflux surgery. Patients were clinically examined and evaluated with the following instruments: Short Form (SF)-36 Health Survey, Gastrointestinal Quality of Life Index, Hospital Anxiety and Depression (HAD) Scale, and Trait Meta-Mood Scale (TMMS)-24. Proportions were compared by using the chi-squared test; averages were compared by using the Student's t-test (with Bonferroni's correction). In general, our patients intervened for GERD showed results lower than normal or close to the lower limit of normal in the administered tests. Patients in the group without hernia were younger (P < 0.001) and with lower American Society of Anaesthesiologists risk. They showed higher scores in the SF-36 dimensions: Physical Functioning, Physical Role and Emotional Role, and lower scores in the Social Role (P < 0.001). They showed lower scores in the Emotional dimension of Gastrointestinal Quality of Life Index (P = 0.0068) and worse results in the Hospital Anxiety and Depression subscales of Anxiety (P < 0.001) and Depression (not significant). Men in the group without hernia showed higher scores than men in the group with hernia in the TMMS subscales corresponding to Emotional Clarity and Emotional Repair (P < 0.001). Women in the group with hernia showed higher scores than women in the group without hernia regarding Emotional Clarity (P = 0.0012). GERD patients showed poor results in all the tests, and patients without hiatal hernia compared with patients with hernia showed higher levels of anxiety, which interfered with their social life. Moreover, they showed lower tolerance to stress and higher frustration, fear, and worry. On the basis of such unfavorable phychoemotional results observed with GERD patients (especially those without hernia) in the different tests, we propose that improving our knowledge of the psychological profile of GERD patients - particularly those without hiatal hernia - could help in designing individualized medical and psychological therapies and increase success rates.
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Afeto , Inteligência Emocional , Refluxo Gastroesofágico/psicologia , Hérnia Hiatal/psicologia , Qualidade de Vida , Adulto , Idoso , Idoso de 80 Anos ou mais , Ansiedade/etiologia , Estudos Transversais , Depressão/etiologia , Medo , Feminino , Frustração , Refluxo Gastroesofágico/cirurgia , Azia/etiologia , Hérnia Hiatal/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Estresse Psicológico/etiologia , Inquéritos e QuestionáriosRESUMO
The kinetics of organic matter and nutrient removal in a pilot vertical subsurface wetland with red ferralitic soil as substrate were evaluated. The wetland (20 m(2)) was planted with Cyperus alternifolius. The domestic wastewater that was treated in the wetland had undergone a primary treatment consisting of a septic moat and a buffer tank. From the sixth week of operation, the performance of the wetland stabilized, and a significant reduction in pollutant concentration of the effluent wastewater was obtained. Also a significant increase of dissolved oxygen (5 mg/l) was obtained. The organic matter removal efficiency was greater than 85% and the nutrient removal efficiency was greater than 75% in the vertical subsurface wetland. Nitrogen and biochemical oxygen demand (BOD) removal could be described by a first-order model. The kinetic constants were 3.64 and 3.27 d(-1) for BOD and for total nitrogen, respectively. Data on the removal of phosphorus were adapted to a second-order model. The kinetic constant was 0.96 (mg/l)(-1) d(-1). The results demonstrated the potential of vertical flow constructed wetlands to clean treated domestic wastewater before discharge into the environment.
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Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Áreas Alagadas , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Cyperus , Desenho de Equipamento , Concentração de Íons de Hidrogênio , Cinética , Nitrogênio/química , Oxigênio/química , Fósforo/análise , Fatores de Tempo , Águas ResiduáriasRESUMO
Copper (Cu) ions have been recognized for their efficacy in inactivating bacteria, including Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease (JD) known for its resilience to unfavorable conditions. However, the response of MAP isolates isolated from cows to Cu exposure remains inadequately understood, as their responses may differ from those of laboratory-adapted reference strains. In this study, we examined the response of MAP isolates obtained from MAP-infected and affected cows to Cu ion treatment, comparing that with the response of the reference strain ATCC 19698 to the same treatment. Three MAP field isolates and the MAP reference strain were exposed to Cu ions, and their viability, protein/lipid damage, ROS production, and gene expression were evaluated in triplicate. Survival differed among isolates, with an isolate from a cow with clinical JD exhibiting increased tolerance to Cu exposure. While Cu treatment induced lipid peroxidation and ROS production across all isolates, genes associated with Cu detoxification and virulence were upregulated, particularly in the reference strain. Whole genome sequencing analysis revealed that, despite genomic similarities between field isolates and the reference strain ATCC 19698, there were differences regarding the presence/absence of genes related with certain virulence factors. Further research on Cu exposure with larger numbers of MAP isolates is needed to explain the stress-induced responses that influence MAP survival during natural infections and in challenging environments.
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INTRODUCTION: Transfontanellar brain ultrasound is an essential tool for monitoring the size of the ventricles in preterm neonates and has many advantages over other alternative diagnostic techniques, including its accessibility and non-use of ionizing radiation. When considering the normal ventricular size, it is essential to have reference measurements based on age-matched populations. The objective of this article is to present our reference measures, based on a sample of preterm infants that we have studied. METHODS: A retrospective observational study was conducted. Measurements of the Levene index, frontal horn thickness, and Evans index were obtained in preterm neonates from 25 to 45 weeks, over a period of 5 years, between January 2016 and December 2020. After applying the exclusion criteria, a sample of 199 patients and 350 ultrasound scans were obtained. The independent samples t-test and the Mann-Whitney test were used for the comparison of samples. RESULTS: The distribution of the right and left Levene indices was normal (Shapiro-Wilk test with pâ¯=â¯0.16 and 0.05, respectively), unlike the thickness distribution of the frontal horns (pâ¯<â¯0.05 on both sides). No significant differences were detected between the sexes (pâ¯=â¯0.08). A linear correlation was found between the biparietal diameter and the Levene index. CONCLUSION: From the results obtained in our study, we present reference tables for ventricular size, with the 3rd, 25th, 50th, 75th, and 97th, being the first ones made in our country.
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Ventrículos Cerebrais , Recém-Nascido Prematuro , Nomogramas , Humanos , Estudos Retrospectivos , Feminino , Masculino , Recém-Nascido , Ventrículos Cerebrais/diagnóstico por imagem , Ventrículos Cerebrais/anatomia & histologia , Valores de Referência , Tamanho do Órgão , Ultrassonografia/métodosRESUMO
BACKGROUND: Alpha-fetoprotein (AFP)-secreting hepatocellular carcinomas (HCC) represent a genetically distinct subset of tumors often associated with a worse prognosis. However, the molecular mechanisms that underlie these phenotypic differences remain poorly understood. METHODS: HCC tumor samples from 27 patients were profiled using the Affymetrix 133 Plus 2.0 GeneChips. GeneGO Metacore software was used to identify altered biologic pathways. Expression validation was confirmed by RT-PCR. Manipulation of miR-675 by overexpression and antagomir-mediated knockdown was carried out with subsequent evaluation of effects on cell behavior by cell cycle, proliferation, invasion, and growth in soft agar assays. RESULTS: We identified a strong relationship between primary tumor H19 gene expression and elevated serum AFP. H19 has recently been identified to encode microRNA-675 (miR-675), and we confirmed the relationship in an independent sample of patients. Pathway analyses of the effect of miR-675 overexpression in hepatoma cells revealed a predominant upregulation of cell adhesion and cell cycle initiation pathways. We have demonstrated that miR-675 mediates increases in proliferation and an accumulation of cells with tetraploid DNA content associated with a repression of Rb. We also demonstrated that overexpression of miR-675 alters cellular morphology, reduces invasive potential, and increases anchorage-independent growth capacity. These findings are consistent with a mesenchymal-to-epithelial transition, associated with a reduction in the expression of the key EMT mediator, Twist1. CONCLUSIONS: Expression of the miR-675 in hepatocellular carcinoma links a dramatic upregulation of proliferative and growth capacity with inhibition of motility in HCC cells.
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Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroRNAs/genética , Proteínas Nucleares/metabolismo , Proteína do Retinoblastoma/metabolismo , Proteína 1 Relacionada a Twist/metabolismo , alfa-Fetoproteínas/metabolismo , Idoso , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Western Blotting , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Adesão Celular , Movimento Celular , Proliferação de Células , Transição Epitelial-Mesenquimal , Feminino , Perfilação da Expressão Gênica , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Luciferases/metabolismo , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Células Tumorais CultivadasRESUMO
The 210Pb-based method has been widely used for five decades to determine absolute ages in recent sediments on the centennial scale. Decoding a chronology from the empirical data set requires a series of assumptions that define a mathematical model of the sedimentary conditions. This work aims to provide a comprehensive review of the fundamentals of the existing family of models assuming a constant flux of excess 210Pb at the sediment surface, namely the CFCS, CRS, and PLUM models, and to present the novel χ-mapping versions of the CFCS and CF models. Their performance is assessed with a selected group of five cores from literature data, with varve chronologies or independent time marks. The PLUM model did not produce reliable chronologies in any of the cores studied. The CRS model is too sensitive to an accurate estimation of the total inventory. A weighted-fit and the χ-mapping versions of the CFCS model are prone to over-represent the younger regions of the core. The CFCS model with least squares fitting and the χ-CF models performed best under the most common sedimentary conditions, which involve temporal variability in the fluxes randomly distributed in the time line. A practical strategy is suggested to identify the occurrence of such sedimentary conditions through the combined use of a set of models, providing this way further strength to the 210Pb-dating.
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Prunus domestica , Monitoramento de Radiação , Chumbo , Radioisótopos de Chumbo/análise , Sedimentos Geológicos , Monitoramento Ambiental/métodosRESUMO
The 210Pb-based method aims at determining the absolute age of recent sediments on the centennial scale. A family of models assumes that at the sediment-water interface the flux of unsupported 210Pb (210Pbexc), F, relates to its initial activity concentration, Ao, and the mass sedimentation rate, w, as: F=Aow. Additional specific assumptions that allow for analytical formulations of the models are: i) constant Ao (CIC), constant F (CF), and constant F with constant w (CFCS). A model with constant w (CSAR) was suggested for completeness but never used because of the lack of a suitable analytical formulation. The TERESA model assumes random and independent variability for Ao and w, described by normal distributions. It systematically generates a large number (â¼105) of potential solutions, whose performance for fitting the empirical 210Pbexc profile is quantified through the χ-function. This work aims to adapt the above methodology to formulate the χ-mapping version of the CSAR model. The performance of the model is evaluated with a set of synthetic and real cores for which an independent chronology is available. CSAR is able to capture the mean sedimentation rate from the 210Pbexc data and provides reliable chronologies and paleorecords of Ao, useful for tracking past changes in sedimentary conditions. CSAR provides an interesting different perspective for researchers working with 210Pb-based dating of recent sediments.
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Monitoramento de Radiação , Monitoramento de Radiação/métodos , Sedimentos Geológicos , Chumbo , Radioisótopos de Chumbo/análise , Água , Monitoramento Ambiental/métodosRESUMO
Conventional 210Pb-dating models use assumptions on sedimentary conditions that allow for analytical formulations. The novel χ-mapping models use numerical methods to generate and test a large number (â¼106) of potential solvers. Empirical data (excess 210Pb vs. mass depth profile) serve to attract the solver that minimizes the χ function (the attractor), and it has been assumed that it also defines the most likely chronology. This work aims to test this assumption in a deep way. In synthetic and varved sediments, the performance of each solver can be quantified through a parameter ξa accounting for the deviation of the model and the true ages. This work studies the complex relationships between χ and ξa using the constant flux (χ-CF) and the constant sediment accumulation rate (CSAR) models, which operate in a parametric 3D space. The full mapping of the 3D χ function serves to find the absolute minimum, for the graphical representation of the complex topology of the attractors, which is model-specific, and for plotting clouds of chronological lines from solvers with varying χ values. The minimum value of ξa (the best chronology) is achieved for a wide range of χ values, including the region of the absolute minimum. In complex cases, tiny changes in χ can result in quite different chronologies. Alternative attractors that include a reference date and an objective function are studied. The results provide guidelines for strengthening the 210Pb-based chronologies.