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1.
Pediatr Blood Cancer ; : e30526, 2023 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-37355858

RESUMO

OBJECTIVES: To characterize the clinical features, treatment, and outcome of children diagnosed with retinoblastoma (RB) at Vietnam National Cancer Hospital. METHODS: The study enrolled all RB patients newly diagnosed at Vietnam National Cancer Hospital from January 2018 to December 2022. The primary endpoint was overall survival (OS) and the eye salvage rate. RESULTS: In total, 139 patients were enrolled, 51.8% patients were male. Median age was 18.9 months. Most patients presented with leukocoria (63.3%), followed by strabismus (14.4%), and 43.9% had bilateral disease. Of 200 eyes, 129 (64.5%) were classified as group E. Extraocular extension was noted in 10 of 139 patients (7.2%). About one-third of the patients lived more than 300 kilometers (km) away from these hospitals, and 17.3% of the patients belonged to minority groups, both of which were dominated by group E and extraocular or high-risk eyes at the time of consultation. Primary enucleation was done for 57 eyes (28.5%), and 51 of 61 patients (83.6%) received eye salvage therapy in bilateral RB group. At study closure, 127 children were alive at the last follow-up, 12 cases were confirmed dead. The 5-year OS and progression-free survival (PFS) rates were 90.3% and 85.9%, respectively. In particular, ethnic minority, distance to hospital more than 150 km, and extraocular disease were significantly associated with higher mortality among children with RB treated in Vietnam National Cancer Hospital. CONCLUSIONS: There is a need to support for screening RB with early symptoms in grassroots medical facilities and raise awareness among patients' families through health education programs. Besides, caring and supporting treatment for patients from the ethnic minority and who live far from hospitals are also extremely necessary.

2.
Methods ; 116: 112-124, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-27965121

RESUMO

This paper describes microbead-based microfluidic systems. Several aspects of bead assays in microfluidics make them advantageous for bioassays in simple microchannels, including enhanced surface-to-volume ratio, improved molecular recognition reaction efficiency, and the wide range of surface functionalization available with commercial microbeads. Two-level SU-8 molds are used to fabricate PDMS microchannels that can hydrodynamically trap different types of microbeads, with characteristic dimensions of tens of microns. The use of these microbead-based microfluidic systems in the biosensing of antibodies, toxins and nucleic acids, as well as in antibody purification will be presented and discussed in this paper.


Assuntos
Anticorpos/isolamento & purificação , Técnicas Biossensoriais/métodos , Técnicas Analíticas Microfluídicas/instrumentação , Micotoxinas/isolamento & purificação , Ácidos Nucleicos/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Dimetilpolisiloxanos/química , Desenho de Equipamento , Corantes Fluorescentes/química , Humanos , Microesferas
3.
Harm Reduct J ; 14(1): 62, 2017 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-28882143

RESUMO

BACKGROUND: Persons who use opioids have a high risk of overdose and associated mortality. In Vietnam, little is known about the characteristics of this population and the persons who are witness to those overdoses. One approach to combatting fatal overdose has been the use of peer interventions in which a friend or injecting partner administers overdose reversal medication, but availability in Vietnam of these medications is limited to pilot programs with aims to expand in the future (Le Minh and V.F. Go, Personal Communication, 2016). The primary objective of this paper is to explore the characteristics associated with witnessing three or more overdoses in a lifetime. METHODS: This cross-sectional analysis used baseline data from a four-arm randomized control trial conducted in Thai Nguyen, Vietnam, known as the Prevention for Positives project. One thousand six hundred seventy-three PWID were included in the analysis. We conducted bivariable and multivariable logistic regression to identify characteristics associated with witnessing three or more overdoses in a lifetime. Characteristics explored included education, employment, marital status, risky drug use behaviors, locations for accessing syringes, recent overdose, history of incarceration, drug treatment, and having slept outside in the past 3 months. RESULTS: Seventy-two percent (n = 1203) of participants had witnessed at least one overdose in their lifetime, and 46% had witnessed three or more overdoses (n = 765). In the multivariable model, having less than secondary education (AOR 0.70; 95% CI 0.57, 0.86), having slept outside in the past 3 months (AOR 1.77; 95% CI 1.31, 2.40), having a history of incarceration (AOR 1.33; 95% CI 1.07, 1.65), having a history of drug treatment (AOR 1.41; 95% CI 1.12, 1.77), experiencing a recent non-fatal overdose (AOR 3.84; 95% CI 2.36, 6.25), injecting drugs daily (AOR 1.79; 95% CI 1.45, 2.20), receptive needle sharing (AOR 1.30; 95% CI 1.04, 1.63), and number of years injecting (AOR 1.04; 95% CI 1.02, 1.07) were significantly associated with witnessing three or more overdoses. CONCLUSIONS: Targeted interventions are needed to train persons witnessing an overdose to administer overdose-reversal medication. This includes targeting persons prior to release from prisons, drug treatment centers, and those accessing syringe exchange programs. Additional research should assess the burden of witnessing an overdose as well as locations for medication distribution. Assessments of the training capacity and needs for implementing these programs among drug using peers in Vietnam are of the utmost importance.


Assuntos
Overdose de Drogas/epidemiologia , Usuários de Drogas/estatística & dados numéricos , Transtornos Relacionados ao Uso de Opioides/epidemiologia , Abuso de Substâncias por Via Intravenosa/epidemiologia , Adulto , Criminosos/estatística & dados numéricos , Estudos Transversais , Escolaridade , Emprego/estatística & dados numéricos , Feminino , Redução do Dano , Pessoas Mal Alojadas/estatística & dados numéricos , Humanos , Estado Civil/estatística & dados numéricos , Uso Comum de Agulhas e Seringas/estatística & dados numéricos , Programas de Troca de Agulhas/estatística & dados numéricos , Fatores de Risco , Assunção de Riscos , Fatores Socioeconômicos , Vietnã/epidemiologia
4.
Antimicrob Agents Chemother ; 60(10): 6341-9, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27527083

RESUMO

The phenotypic expression of methicillin resistance among coagulase-negative staphylococci (CoNS) is heterogeneous regardless of the presence of the mecA gene. The potential discordance between phenotypic and genotypic results has led to the use of vancomycin for the treatment of CoNS infective endocarditis (IE) regardless of methicillin MIC values. In this study, we assessed the outcome of methicillin-susceptible CoNS IE among patients treated with antistaphylococcal ß-lactams (ASB) versus vancomycin (VAN) in a multicenter cohort study based on data from the International Collaboration on Endocarditis (ICE) Prospective Cohort Study (PCS) and the ICE-Plus databases. The ICE-PCS database contains prospective data on 5,568 patients with IE collected between 2000 and 2006, while the ICE-Plus database contains prospective data on 2,019 patients with IE collected between 2008 and 2012. The primary endpoint was in-hospital mortality. Secondary endpoints were 6-month mortality and survival time. Of the 7,587 patients in the two databases, there were 280 patients with methicillin-susceptible CoNS IE. Detailed treatment and outcome data were available for 180 patients. Eighty-eight patients received ASB, while 36 were treated with VAN. In-hospital mortality (19.3% versus 11.1%; P = 0.27), 6-month mortality (31.6% versus 25.9%; P = 0.58), and survival time after discharge (P = 0.26) did not significantly differ between the two cohorts. Cox regression analysis did not show any significant association between ASB use and the survival time (hazard ratio, 1.7; P = 0.22); this result was not affected by adjustment for confounders. This study provides no evidence for a difference in outcome with the use of VAN versus ASB for methicillin-susceptible CoNS IE.


Assuntos
Endocardite Bacteriana/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus/patogenicidade , Vancomicina/uso terapêutico , beta-Lactamas/uso terapêutico , Idoso , Coagulase/metabolismo , Estudos de Coortes , Endocardite Bacteriana/microbiologia , Endocardite Bacteriana/mortalidade , Feminino , Mortalidade Hospitalar , Humanos , Masculino , Meticilina/farmacologia , Pessoa de Meia-Idade , Estudos Prospectivos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/mortalidade , Staphylococcus/efeitos dos fármacos , Staphylococcus/metabolismo
5.
J Antimicrob Chemother ; 71(7): 2022-30, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27029851

RESUMO

OBJECTIVES: Although controversy exists regarding the efficacy of antibiotic prophylaxis for patients at risk of infective endocarditis, expert committees continue to publish recommendations for antibiotic prophylaxis regimens. This study aimed to evaluate the efficacy of four antimicrobial regimens for the prevention of bacteraemia following dental extractions. METHODS: The study population included 266 adults requiring dental extractions who were randomly assigned to the following five groups: control (no prophylaxis); 1000/200 mg of amoxicillin/clavulanate intravenously; 2 g of amoxicillin by mouth; 600 mg of clindamycin by mouth; and 600 mg of azithromycin by mouth. Venous blood samples were collected from each patient at baseline and at 30 s, 15 min and 1 h after dental extractions. Samples were inoculated into BACTEC Plus culture bottles and processed in the BACTEC 9240. Conventional microbiological techniques were used for subcultures and further identification of the isolated bacteria. The trial was registered at ClinicalTrials.gov with ID number NCT02115776. RESULTS: The incidence of bacteraemia in the control, amoxicillin/clavulanate, amoxicillin, clindamycin and azithromycin groups was: 96%, 0%, 50%, 87% and 81%, respectively, at 30 s; 65%, 0%, 10%, 65% and 49% at 15 min; and 18%, 0%, 4%, 19% and 18% at 1 h. Streptococci were the most frequently identified bacteria. The percentage of positive blood cultures at 30 s post-extraction was lower in the amoxicillin/clavulanate group than in the amoxicillin group (P < 0.001). The incidence of bacteraemia in the clindamycin group was similar to that in the control group. CONCLUSIONS: Bacteraemia following dental extractions was undetectable with amoxicillin/clavulanate prophylaxis. Alternative antimicrobial regimens should be sought for patients allergic to the ß-lactams.


Assuntos
Combinação Amoxicilina e Clavulanato de Potássio/administração & dosagem , Antibacterianos/administração & dosagem , Antibioticoprofilaxia/métodos , Bacteriemia/prevenção & controle , Extração Dentária/efeitos adversos , Inibidores de beta-Lactamases/administração & dosagem , Administração Intravenosa , Adolescente , Adulto , Técnicas Bacteriológicas , Sangue/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento , Adulto Jovem
6.
JCO Glob Oncol ; 10: e2300234, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38359370

RESUMO

PURPOSE: Gut microbiota play an important role in human health, including cancer. Cancer and its treatment, in turn, may alter the gut microbiome. To understand this complex relationship, we profiled the gut microbiome of 356 Vietnamese patients with breast cancer. MATERIALS AND METHODS: Stool samples were collected before chemotherapy, with 162 pre- and 194 postsurgery. The gut microbiome was measured by shotgun metagenomic sequencing. Associations of gut microbial diversity, taxa abundance, and gut microbiome health index (GMHI) with sociodemographic, clinical factors, and tumor characteristics were evaluated. RESULTS: Postsurgery samples were associated with significantly lower α- and ß-diversities (P < .001) and showed significant differences in the abundance of 15% of 2,864 investigated taxa (false discovery rate [FDR] <0.1) compared with presurgery samples. An unhealthy gut microbiome was prevalent among patients with breast cancer, with a mean GMHI of -0.79 and -2.81 in pre- and postsurgery stool samples, respectively. In an analysis of 162 presurgery stool samples, diagnosis delay was significantly associated with lower α-diversity, variation in ß-diversity, an increased abundance of species Enorma massiliensis, and a decreased abundance of Faecalicoccus pleomorphus. High intake of fiber was significantly associated with lower α-diversity and a higher abundance of species belonging to Bifidobacterium, Prevotella, and Bacteroides gena (FDR < 0.1). We did not find that cancer stage and subtype, menopausal status, comorbidity, antibiotic use during 3 months before stool collection, or physical activity was significantly associated with α- and ß-diversities or GMHI although a few significant differences were observed in taxa abundance. CONCLUSION: Our study revealed that diagnosis delay, high fiber intake, and breast cancer surgery, which is always followed by antibiotic prophylaxis in Vietnam, led to a less diverse and unhealthy gut microbiome among patients with breast cancer.


Assuntos
Neoplasias da Mama , Microbioma Gastrointestinal , Humanos , Feminino , Vietnã/epidemiologia , Fezes/microbiologia , Metagenoma
7.
RSC Adv ; 12(13): 7973-7979, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35424776

RESUMO

In this paper, the structural, electronic, and transport properties of Janus GaInX3 (X = S, Se, Te) single-layers are investigated by a first-principles calculations. All three structures of GaInX3 are examined to be stable based on the analysis of their phonon dispersions, cohesive energy, and Born's criteria for mechanical stability. At the ground state, The Janus GaInX3 is a semiconductor in which its bandgap decreases as the chalcogen element X moves from S to Te. Due to the vertical asymmetric structure, a difference in the vacuum level between the two surfaces of GaInX3 is found, leading to work functions on the two sides being different. The Janus GaInX3 exhibit high directional isotropic transport characteristics. Particularly, GaInX3 single-layers have high electron mobility, which could make them potential materials for applications in electronic nanodevices.

8.
Scand J Immunol ; 73(6): 508-11, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21352257

RESUMO

Plasma cells sustain antibody production and hence are an essential part of immune protection. In the mucosa-associated lymphoid tissues plasma cells secrete IgA antibodies which protect the organism from invasion by pathogenic bacteria while in the bone marrow they produce the antibodies which guarantee long-term humoral immune protection. The various lymphoid organs provide specific microenvironments which support plasma cell survival. In particular, in the bone marrow, highly specialized survival niches are established by the underlying stromal reticular cells which permit plasma cells to survive for years. In some situations, however, the antibody may be detrimental to the organism. In those auto immune diseases, where plasma cells play a pathological role by producing the auto antibodies, new strategies are needed to interfere with the lifespan of plasma cells and thus to diminish their numbers. The recent finding that eosinophils are essential for the long-term survival of plasma cells in the bone marrow provides a new therapeutic target to modulate the plasma cell survival niche.


Assuntos
Sobrevivência Celular/imunologia , Tecido Linfoide/citologia , Plasmócitos/citologia , Animais , Formação de Anticorpos/imunologia , Humanos , Tecido Linfoide/imunologia , Plasmócitos/imunologia
9.
J Hosp Infect ; 104(2): 214-235, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31715282

RESUMO

Mycobacterial infection-related morbidity and mortality in patients following cardiopulmonary bypass surgery is high and there is a growing need for a consensus-based expert opinion to provide international guidance for diagnosing, preventing and treating in these patients. In this document the International Society for Cardiovascular Infectious Diseases (ISCVID) covers aspects of prevention (field of hospital epidemiology), clinical management (infectious disease specialists, cardiac surgeons, ophthalmologists, others), laboratory diagnostics (microbiologists, molecular diagnostics), device management (perfusionists, cardiac surgeons) and public health aspects.


Assuntos
Infecção Hospitalar , Infecções por Mycobacterium não Tuberculosas , Mycobacterium , Antibacterianos/uso terapêutico , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/métodos , Cardiologia , Ponte Cardiopulmonar , Doenças Transmissíveis , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Infecção Hospitalar/prevenção & controle , Contaminação de Equipamentos , Humanos , Mycobacterium/isolamento & purificação , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Infecções por Mycobacterium não Tuberculosas/prevenção & controle , Fatores de Risco , Sociedades Médicas , Reino Unido
10.
Nanotechnology ; 20(1): 015503, 2009 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-19417254

RESUMO

Electric fields generated by single square and sinusoidal voltage pulses with amplitudes below 2 V were used to assist the covalent immobilization of single-stranded, thiolated DNA probes, onto a chemically functionalized SiO2 surface and to assist the specific hybridization of single-stranded DNA targets with immobilized complementary probes. The single-stranded immobilized DNA probes were either covalently immobilized (chemisorption) or electrostatically adsorbed (physisorption) to a chemically functionalized surface. Comparing the speed of electric field assisted immobilization and hybridization with the corresponding control reactions (without electric field), an increase of several orders of magnitude is observed, with the reaction timescaled down from 1 to 2 h to a range between 100 ns and 1 ms. The influence of the shape of the voltage pulse (square versus sinusoidal) and its duration were studied for both immobilization and hybridization reactions. The results show that pulsed electric fields are a useful tool to achieve temporal and spatial control of surface immobilization and hybridization reactions of DNA.


Assuntos
Eletricidade , Hibridização de Ácido Nucleico/métodos , DNA/metabolismo
11.
Sci Rep ; 9(1): 5356, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30926833

RESUMO

The primary Brazilian malaria vector, Nyssorhynchus darlingi (formerly Anopheles darlingi), ranges from 0°S-23°S across three biomes (Amazonia, Cerrado, Mata Atlântica). Rising temperatures will increase mosquito developmental rates, and models predict future malaria transmission by Ny. darlingi in Brazil will shift southward. We reared F1 Ny. darlingi (progeny of field-collected females from 4 state populations across Brazil) at three temperatures (20, 24, 28 °C) and measured key life-history traits. Our results reveal geographic variation due to both genetic differences among localities and plastic responses to temperature differences. Temperature significantly altered all traits: faster larval development, shorter adult life and overall lifespan, and smaller body sizes were seen at 28 °C versus 20 °C. Low-latitude Amazonia mosquitoes had the fastest larval development at all temperatures, but at 28 °C, average development rate of high-latitude Mata Atlântica mosquitoes was accelerated and equivalent to low-latitude Amazonia. Body size of adult mosquitoes from the Mata Atlântica remained larger at all temperatures. We detected genetic variation in the plastic responses among mosquitoes from different localities, with implications for malaria transmission under climate change. Faster development combined with larger body size, without a tradeoff in adult longevity, suggests vectorial capacities of some Mata Atlântica populations may significantly increase under warming climates.


Assuntos
Características de História de Vida , Malária/epidemiologia , Mosquitos Vetores/fisiologia , Temperatura , Adaptação Fisiológica , Brasil , Geografia , Longevidade , Malária/prevenção & controle , Malária/transmissão , Mosquitos Vetores/parasitologia
13.
J Chromatogr A ; 1487: 242-247, 2017 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-28110948

RESUMO

Aqueous two phase systems (ATPS) offer great potential for selective separation of a wide range of biomolecules by exploring differences in molecular solubility in each of the two immiscible phases. However, ATPS use has been limited due to the difficulty in predicting the behavior of a given biomolecule in the partition environment together with the empirical and time-consuming techniques that are used for the determination of partition and extraction parameters. In this work, a fast and novel technique based on a microfluidic platform and using fluorescence microscopy was developed to determine the partition coefficients of biomolecules in different ATPS. This method consists of using a microfluidic device with a single microchannel and three inlets. In two of the inlets, solutions containing the ATPS forming components were loaded while the third inlet was fed with the FITC tagged biomolecule of interest prepared in milli-Q water. Using fluorescence microscopy, it was possible to follow the location of the FITC-tagged biomolecule and, by simply varying the pumping rates of the solutions, to quickly test a wide variety of ATPS compositions. The ATPS system is allowed 4min for stabilization and fluorescence micrographs are used to determine the partition coefficient.The partition coefficients obtained were shown to be consistent with results from macroscale ATPS partition. This process allows for faster screening of partition coefficients using only a few microliters of material for each ATPS composition and is amenable to automation. The partitioning behavior of several biomolecules with molecular weights (MW) ranging from 5.8 to 150kDa, and isoelectric points (pI) ranging from 4.7 to 6.4 was investigated, as well as the effect of the molecular weight of the polymer ATPS component.


Assuntos
Técnicas Analíticas Microfluídicas/métodos , Microscopia de Fluorescência , Ponto Isoelétrico , Peso Molecular , Polietilenoglicóis/química , Polímeros/química , Água
14.
Biosens Bioelectron ; 87: 823-831, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27657844

RESUMO

For a point-of-use analytical device to be successful in real-world applications, it needs to be rapid, simple to operate and, ideally, able to multiplex the detection of several analytes and samples. Mycotoxin detection in food and feedstock in particular has become increasingly relevant as these toxins, such as ochratoxin A (OTA), aflatoxin B1 (AFB1) and deoxynivalenol (DON), are subject to strict regulations and recommendations in the European Union. A novel, simple, negative pressure-driven device with manually operated magnetic valves was developed and the simultaneous immunodetection of these three mycotoxins was demonstrated via the laminar flow patterning of probes in an area of ≈0.12mm2 and subsequent chemiluminescence generation via HRP-labeled antibodies. The three mycotoxins were detected in less than 20min at concentrations of 100ng/mL for OTA and DON and 3ng/mL for AFB1, spiked in a sample under analysis and simultaneously compared to a toxin-free reference and a standard contaminated with critical target concentrations. The on-chip optical detection was performed in a single acquisition step by integrating a microfabricated array of 25×25µm2 hydrogenated amorphous silicon (a-Si:H) photosensors below the microfluidic chip. The device presented in this work is simple and effective for point-of-use multiplexing of immunoassays and was applied in this work to the screening of mycotoxins.


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais/instrumentação , Imunoensaio/instrumentação , Dispositivos Lab-On-A-Chip , Ocratoxinas/análise , Tricotecenos/análise , Desenho de Equipamento , Contaminação de Alimentos/análise , Peroxidase do Rábano Silvestre/química , Imunoconjugados/química , Limite de Detecção , Medições Luminescentes/instrumentação
15.
Clin Microbiol Infect ; 23(8): 544-549, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28159672

RESUMO

OBJECTIVES: Left-sided methicillin-susceptible Staphylococcus aureus (MSSA) endocarditis treated with cloxacillin has a poorer prognosis when the vancomycin minimum inhibitory concentration (MIC) is ≥1.5 mg/L. We aimed to validate this using the International Collaboration on Endocarditis cohort and to analyse whether specific genetic characteristics were associated with a high vancomycin MIC (≥1.5 mg/L) phenotype. METHODS: All patients with left-sided MSSA infective endocarditis treated with antistaphylococcal ß-lactam antibiotics between 2000 and 2006 with available isolates were included. Vancomycin MIC was determined by Etest as either high (≥1.5 mg/L) or low (<1.5 mg/L). Isolates underwent spa typing to infer clonal complexes and multiplex PCR for identifying virulence genes. Univariate analysis was performed to evaluate the association between in-hospital and 1-year mortality, and vancomycin MIC phenotype. RESULTS: Sixty-two cases met the inclusion criteria. Vancomycin MIC was low in 28 cases (45%) and high in 34 cases (55%). No significant differences in patient demographic data or characteristics of infection were observed between patients with infective endocarditis due to high and low vancomycin MIC isolates. Isolates with high and low vancomycin MIC had similar distributions of virulence genes and clonal lineages. In-hospital and 1-year mortality did not differ significantly between the two groups (32% (9/28) vs. 27% (9/34), p 0.780; and 43% (12/28) vs. 29% (10/34), p 0.298, for low and high vancomycin MIC respectively). CONCLUSIONS: In this international cohort of patients with left-sided MSSA endocarditis treated with antistaphylococcal ß-lactams, vancomycin MIC phenotype was not associated with patient demographics, clinical outcome or virulence gene repertoire.


Assuntos
Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Endocardite Bacteriana/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Vancomicina/farmacologia , beta-Lactamas/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Endocardite Bacteriana/microbiologia , Endocardite Bacteriana/mortalidade , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Tipagem Molecular , Reação em Cadeia da Polimerase Multiplex , Estudos Prospectivos , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Análise de Sobrevida , Resultado do Tratamento , Fatores de Virulência/genética
16.
Nucleic Acids Res ; 32(9): e70, 2004 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-15148343

RESUMO

A flat microdevice which incorporates a thin-film amorphous silicon (a-Si:H) photodetector with an upper layer of functionalized SiO2 is used to quantify the density of both immobilized and hybridized DNA oligonucleotides labeled with a fluorophore. The device is based on the photoconductivity of hydrogenated amorphous silicon in a coplanar electrode configuration. Excitation, with near UV/blue light, of a single-stranded DNA molecule tagged with the fluorophore 1-(3-(succinimidyloxycarbonyl)benzyl)-4-(5-(4-methoxyphenyl)oxazol-2-yl) pyridinium bromide (PyMPO), results in the emission of visible light. The emitted light is then converted into an electrical signal in the photodetector, thus allowing the optoelectronic detection of the DNA molecules. The detection limit of the present device is of the order of 1 x 10(12) molecules/cm2 and is limited by the efficiency of the filtering of the excitation light. A surface density of 33.5 +/- 4.0 pmol/cm2 was measured for DNA covalently immobilized to the functionalized SiO2 thin film and a surface density of 3.7 +/- 1.5 pmol/cm2 was measured for the complementary DNA hybridized to the bound DNA. The detection concept explored can enable on-chip electronic data acquisition, improving both the speed and the reliability of DNA microarrays.


Assuntos
Pareamento de Bases , Sondas de DNA/análise , Análise de Sequência com Séries de Oligonucleotídeos/instrumentação , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Sequência de Bases , Calibragem , Sondas de DNA/química , Sondas de DNA/genética , DNA de Cadeia Simples/análise , DNA de Cadeia Simples/química , DNA de Cadeia Simples/genética , Eletrônica , Corantes Fluorescentes/análise , Luz , Hibridização de Ácido Nucleico , Reprodutibilidade dos Testes , Semicondutores , Sensibilidade e Especificidade , Silício
17.
J Mater Chem B ; 4(12): 2153-2162, 2016 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32263182

RESUMO

Semiconductor nanowires are emerging as promising building blocks for biosensors enabling direct electrical detection of various biomolecules. In this framework, two-terminal Schottky-barrier silicon (Si) nanowire arrays that exhibit memristive electrical response, so-called memristive devices, are bio-functionalized and converted to memristive biosensors for bio-detection purposes. A comparative analysis of three bio-functionalization strategies is proposed here in order to design and develop optimum memristive biosensors to be implemented in label-free sensing applications. The surface of the device is modified with an anti-free-Prostate Specific Antigen (PSA) antibody as the case of study via: (a) direct adsorption on the device surface, (b) a bio-affinity approach using biotin-streptavidin combination and (c) covalent attachment using (3-glycidyloxypropyl)trimethoxysilane (GPTES). The optimum memristive biosensor is defined via the calibration and comparative study of the biosensors' electrical response under controlled environmental conditions (humidity and temperature) in order to maximize the performance of the biosensor. In addition, it is demonstrated that the direct passive adsorption strategy presents double the performance of the other two methods. The uptake of biological molecules on the nanostructure surface is verified by atomic force microscopy and confocal microscopy. Scanning electron microscopy reveals the details of the surface morphology of the nanofabricated structures before and after bio-functionalization for the three methods applied. The system shows potential for general application in molecular diagnostics, and, in particular, for the early detection of prostate cancer.

18.
J Mol Biol ; 313(1): 49-69, 2001 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-11601846

RESUMO

The crystal structure of a novel Cre-Lox synapse was solved using phases from multiple isomorphous replacement and anomalous scattering, and refined to 2.05 A resolution. In this complex, a symmetric protein trimer is bound to a Y-shaped three-way DNA junction, a marked departure from the pseudo-4-fold symmetrical tetramer associated with Cre-mediated LoxP recombination. The three-way DNA junction was accommodated by a simple kink without significant distortion of the adjoining DNA duplexes. Although the mean angle between DNA arms in the Y and X structures was similar, adjacent Cre trimer subunits rotated 29 degrees relative to those in the tetramers. This rotation was accommodated at the protein-protein and DNA-DNA interfaces by interactions that are "quasi-equivalent" to those in the tetramer, analogous to packing differences of chemically identical viral subunits at non-equivalent positions in icosahedral capsids. This structural quasi-equivalence extends to function as Cre can bind to, cleave and perform strand transfer with a three-way Lox substrate. The structure explains the dual recognition of three and four-way junctions by site-specific recombinases as being due to shared structural features between the differently branched substrates and plasticity of the protein-protein interfaces. To our knowledge, this is the first direct demonstration of quasi-equivalence in both the assembly and function of an oligomeric enzyme.


Assuntos
Sítios de Ligação Microbiológicos/genética , DNA Bacteriano/química , DNA Bacteriano/metabolismo , Integrases/química , Integrases/metabolismo , Conformação de Ácido Nucleico , Recombinação Genética , Proteínas Virais/química , Proteínas Virais/metabolismo , Sequência de Bases , Sítios de Ligação , Catálise , Cristalografia por Raios X , DNA Bacteriano/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Modelos Moleculares , Ligação Proteica , Estrutura Quaternária de Proteína , Subunidades Proteicas , Rotação , Relação Estrutura-Atividade
19.
Biosens Bioelectron ; 21(6): 888-93, 2005 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-16257657

RESUMO

A single square voltage pulse applied to metal electrodes underneath a silicon dioxide film upon which DNA probes are immobilized allows the discrimination of DNA targets with a single base mismatch during hybridization. Pulse duration, magnitude and slew rate of the voltage pulse are all key factors controlling the rates of electric field assisted hybridization. Although pulses with 1 V, lasting less than 1 ms and with a rise/fall times of 4.5 ns led to maximum hybridization of fully complementary strands, lack of stringency did not allow the discrimination of single base mismatches. However, by choosing pulse conditions that are slightly off the optimum, the selectivity for discriminating single base mismatches could be improved up to a factor approximately 5 when the mismatch was in the middle of the strand and up to approximately 1.5 when the mismatch was on the 5'-end and. These results demonstrate that hybridization with the appropriate electric field pulse provides a new, site-specific, approach to the discrimination of single nucleotide polymorphisms in the sub-millisecond time scale, for addressable DNA microarrays.


Assuntos
Pareamento Incorreto de Bases , Análise Mutacional de DNA/métodos , DNA/análise , DNA/química , Eletroquímica/métodos , Hibridização In Situ/métodos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Polimorfismo de Nucleotídeo Único , DNA/efeitos da radiação , Eletroquímica/instrumentação , Campos Eletromagnéticos , Análise de Sequência com Séries de Oligonucleotídeos/instrumentação
20.
Int J Surg ; 15: 23-6, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25641717

RESUMO

INTRODUCTION: The recurrence rate of giant hiatus hernias (GHH) following repair is high (30%) and increases with the hernia size and previous revision surgery. The mechanism of recurrence is poorly understood. METHODS: This is a retrospective cohort study of all consecutive patients who underwent repair of giant hiatus hernia in a tertiary upper GI referral centre from November 2000 to November 2014. Patients who underwent redo surgery were identified and data on intra-operative findings and procedure performed at primary and redo surgery from their operation notes were collected. RESULTS: A total of 81 patients underwent primary repair of GHH over the 14 year study period. 10 (12.3%) had symptomatic/radiological recurrence of which 4 were found to have the distal stomach herniating into the chest despite having an intact intra-abdominal wrap/gastropexy. To prevent migration of the distal stomach into the chest, distal gastropexy - fixing the antrum to the anterior abdominal wall, was added to 'conventional' gastropexy in 5 subsequent cases, in whom the antrum was in the chest preoperatively. These cases have no evidence of recurrence at the end of 6 months follow up. CONCLUSION: Securing the antrum of stomach to the anterior abdominal wall may prevent migration of the distal stomach and other infracolic organs into the chest and thus reduce recurrence of some GHH where antrum had been in chest previously.


Assuntos
Gastropexia/métodos , Hérnia Hiatal/patologia , Hérnia Hiatal/cirurgia , Parede Abdominal/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Laparoscopia , Masculino , Pessoa de Meia-Idade , Antro Pilórico/cirurgia , Recidiva , Reoperação , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
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