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1.
Molecules ; 26(4)2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670660

RESUMO

Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO2 photocatalyst under UV irradiation. The mesoporous AC-TiO2 synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO2 was evaluated as a function of three input variables viz. catalyst load (2-4 g), reaction time (15-45 min) and pH (6-9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R2) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%.


Assuntos
Compostos Azo/efeitos da radiação , Benzotiazóis/efeitos da radiação , Carvão Vegetal/química , Fotólise/efeitos da radiação , Titânio/química , Raios Ultravioleta , Análise de Variância , Catálise/efeitos da radiação , Cor , Concentração de Íons de Hidrogênio , Cinética , Nefelometria e Turbidimetria , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
2.
J Chromatogr A ; 1642: 462000, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33684874

RESUMO

The anti-citrillinated protein antibody (ACPA) plays an important role in early diagnosis of rheumatoid arthritis (RA), and is usually detected by using cyclic citrullinated peptide (CCP) as antigen. The ACPA against CCP test is usually performed utilizing enzyme-linked immunosorbent assay (ELISA), but the ELISA is expensive and time-consuming. Here, latex particle-enhanced turbidimetric immunoassay (LTIA) based on CCP-immobilized latex bead was proposed for fast measurements of ACPA of RA patients. CCP-immobilized latex bead was fabricated through three methods, including direct coupling, overall coupling and layer by layer coupling. According to the optimized experiments, layer-by-layer coupling was the best method with advantages of time-saving, simple operation and good repeatability. In addition, a spacer arm of appropriate length between latex beads and CCP could avoid stereoscopic obstacles and make ACPA closer to CCP. The CCP-immobilized latex bead based on layer by layer coupling (CCP-LB-LLC) was used for assembling the homemade kit, which was applied in fast measurements of ACPA through LTIA. The homemade kit possessed a low limit of detection (0.2 U/mL) and an acceptable the batch-to-batch reproducibility. In addition, the homemade kit can be stored at 4 °C for at least one month. When used to detect 20 clinical samples, the results of homemade kit were consistent with commercial ELISA. Furthermore, LTIA based on the homemade kit was simpler and cheaper than ELISA. These results demonstrated that the homemade kit could be useful for diagnosis of RA patients.


Assuntos
Autoanticorpos/análise , Citrulinação/imunologia , Imunoturbidimetria/métodos , Látex/química , Microesferas , Peptídeos Cíclicos/química , Animais , Artrite Reumatoide/diagnóstico , Artrite Reumatoide/imunologia , Autoanticorpos/imunologia , Bovinos , Humanos , Nefelometria e Turbidimetria , Tamanho da Partícula , Polissorbatos/química , Poliestirenos/química , Reprodutibilidade dos Testes , Soroalbumina Bovina/química , Eletricidade Estática , Fatores de Tempo
3.
Carbohydr Polym ; 259: 117775, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33674017

RESUMO

Triple-helical aggregates (THAs) have been proven to affect the biological activities and functional properties of triple-helix polysaccharides. Thus, it's urgent to seek a method to reduce the size of THAs while preserving independent triple helices (ITHs). In this study, the effects of alkali-neutralization (AN) treatment on THAs and ITHs of curdlan were studied. The positive values of the Congo red test data (R2>0.99) fitted using a Logistic model indicated that AN treatment (CNaOH/HCl>0.28 mol/L) facilitated the disaggregation of THAs. Congo red test, sedimentation test, and turbidity test showed that AN treatment (CNaOH/HCl = 1.0 mol/L) significantly reduced the size of THAs to approximately 1 µm while effectively increasing the relative amount of ITHs to approximately 199 %. Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that AN treatment basically unchanged the primary structure of curdlan chains, but affected the crystalline structure and the intermolecular and intramolecular hydrogen bonding of curdlan.


Assuntos
Álcalis/química , beta-Glucanas/química , Configuração de Carboidratos , Vermelho Congo/química , Nefelometria e Turbidimetria , Tamanho da Partícula , Compostos de Sódio/química , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Food Chem ; 345: 128849, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-33601660

RESUMO

The study was to investigate the role of direct current magnetic field (DC-MF) for water-holding capacity (WHC) of myofibrillar protein gels and to understand potential mechanisms. Samples were subjected to DC-MF with different intensities (3.5, 3.8, 9.5 and 10.4 mT), and DC-MF treatment significantly improved WHC compared with control (46.09%), reaching the maximum value of 50.36% at 3.8 mT. The main reason for the increase in WHC might be that DC-MF modified the protein structure via unfolding, re-crosslinking and aggregation of proteins, which was supported by the increased intensity of tyrosine, aliphatic and tryptophan residues, and reduced reactive sulfhydryl (2.97 to 1.94). And the re-crosslinking between molecules was maintained mainly through hydrophobic interactions and disulfide bonds. Besides, DC-MF treatment helped to generate a relatively loose and uniform microstructure to trap more water as shown by electron microscope image, which was consistent with the highest WHC at 3.8 mT.


Assuntos
Géis/química , Proteínas Musculares/química , Água/química , Animais , Dissulfetos/química , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica , Nefelometria e Turbidimetria , Ressonância Magnética Nuclear Biomolecular , Agregados Proteicos , Solubilidade , Suínos
5.
PLoS One ; 15(9): e0225293, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991576

RESUMO

Grain hardness is an important quality trait of cereal crops. In wheat, it is mainly determined by the Hardness locus that harbors genes encoding puroindoline A (PINA) and puroindoline B (PINB). Any deletion or mutation of these genes leading to the absence of PINA or to single amino acid changes in PINB leads to hard endosperms. Although it is generally acknowledged that hardness is controlled by adhesion strength between the protein matrix and starch granules, the physicochemical mechanisms connecting puroindolines and the starch-protein interactions are unknown as of this time. To explore these mechanisms, we focused on PINA. The overexpression in a hard wheat cultivar (cv. Courtot with the Pina-D1a and Pinb-D1d alleles) decreased grain hardness in a dose-related effect, suggesting an interactive process. When PINA was added to gliadins in solution, large aggregates of up to 13 µm in diameter were formed. Turbidimetry measurements showed that the PINA-gliadin interaction displayed a high cooperativity that increased with a decrease in pH from neutral to acid (pH 4) media, mimicking the pH change during endosperm development. No turbidity was observed in the presence of isolated α- and γ-gliadins, but non-cooperative interactions of PINA with these proteins could be confirmed by surface plasmon resonance. A significant higher interaction of PINA with γ-gliadins than with α-gliadins was observed. Similar binding behavior was observed with a recombinant repeated polypeptide that mimics the repeat domain of gliadins, i.e., (Pro-Gln-Gln-Pro-Tyr)8. Taken together, these results suggest that the interaction of PINA with a monomeric gliadin creates a nucleation point leading to the aggregation of other gliadins, a phenomenon that could prevent further interaction of the storage prolamins with starch granules. Consequently, the role of puroindoline-prolamin interactions on grain hardness should be addressed on the basis of previous observations that highlight the similar subcellular routing of storage prolamins and puroindolines.


Assuntos
Grão Comestível/metabolismo , Gliadina/metabolismo , Dureza/fisiologia , Proteínas de Plantas/metabolismo , Triticum/metabolismo , Produção Agrícola , Difusão Dinâmica da Luz , Grão Comestível/química , Gliadina/química , Concentração de Íons de Hidrogênio , Nefelometria e Turbidimetria , Tamanho da Partícula , Proteínas de Plantas/química , Agregados Proteicos/fisiologia , Ligação Proteica/fisiologia , Domínios Proteicos/fisiologia , Sequências Repetitivas de Aminoácidos/fisiologia , Amido/química , Amido/metabolismo , Ressonância de Plasmônio de Superfície , Triticum/química
6.
J Vis Exp ; (159)2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32478745

RESUMO

Primary clarification is an essential step in a biomanufacturing process for the initial removal of cells from therapeutic products within the harvested cell culture fluid. While traditional methods like centrifugation or filtration are widely implemented for cell removal, the equipment for these processes have large footprints and operation can involve contamination risks and filter fouling. Additionally, traditional methods may not be ideal for continuous bioprocessing schemes for primary clarification. Thus, an alternate application using acoustic (sound) waves was investigated to continuously separate cells from the cell culture fluid. Presented in this study is a detailed protocol for using a bench-scale acoustic wave separator (AWS) for the primary separation of culture fluid containing a monoclonal IgG1 antibody from a CHO cell bioreactor harvest. Representative data are presented from the AWS and demonstrate how to achieve effective cell clarification and product recovery. Finally, potential applications for AWS in continuous bioprocessing are discussed. Overall, this study provides a practical and general protocol for the implementation of AWS in primary clarification for CHO cell cultures and further describes its application potential in continuous bioprocessing.


Assuntos
Acústica/instrumentação , Técnicas de Cultura de Células/métodos , Animais , Células CHO , Contagem de Células , Cricetinae , Cricetulus , Nefelometria e Turbidimetria , Software , Temperatura
7.
Sci Total Environ ; 736: 139612, 2020 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-32470688

RESUMO

The lagoon of Venice has always been affected by the regional geomorphological evolution, anthropogenic stressors and global changes. Different morphological settings and variable biogeophysical conditions characterize this continuously evolving system that rapidly responds to the anthropic impacts. When the lockdown measures were enforced in Italy to control the spread of the SARS-CoV-2 infection on March 10th 2020, the ordinary urban water traffic around Venice, one of the major pressures in the lagoon, came to a halt. This provided a unique opportunity to analyse the environmental effects of restrictions to mobility on water transparency. Pseudo true-colour composites Sentinel-2 satellite imagery proved useful for qualitative visual interpretation, showing the reduction of the vessel traffic and their wakes from the periods before and during the SARS-CoV-2 outbreak. A quantitative analysis of suspended matter patterns, based on satellite-derived turbidity, in the absence of traffic perturbations, allowed to focus on natural processes and the residual stress from human activities that continued throughout the lockdown. We conclude that the high water transparency can be considered as a transient condition determined by a combination of natural seasonal factors and the effects of COVID-19 restrictions.


Assuntos
Infecções por Coronavirus , Monitoramento Ambiental , Pandemias , Pneumonia Viral , Qualidade da Água , Betacoronavirus , Atividades Humanas , Humanos , Itália , Nefelometria e Turbidimetria , Imagens de Satélites
8.
Ann Biol Clin (Paris) ; 78(2): 147-155, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32319943

RESUMO

OBJECTIVE: The aim of this study was to evaluate the analytical performance of the Alinity®c Abbott compared to the Architect® immunoassay system for the determination of drugs having a narrow therapeutic index. METHODS: Valproic acid, amikacin, gentamicin, phenobarbital and vancomycin were analyzed using Particle-Enhanced Turbidimetric Inhibitor Immunoassay (Petinia), phenytoin and theophylline were analyzed using an immunoenzymatic method and a colorimetric method was performed to quantify lithium. The methods were validated according to the total error approach. Seven validation standards were analyzed in quintuplet during four days to establish the limits of the methods. Dilution integrity and interferences (hemolysis and high concentrations of bilirubin and lipids) were also tested. Depending on the analyte, the results obtained for twenty to forty patients on the Alinity® were compared to those obtained on the Architect®. RESULTS: The bias and the coefficients of variation for repeatability and for intermediate precision were lower than 15% for all drugs. Accuracy profiles were acceptable (acceptance limits fixed at 30%) in the validated ranges. The lower limits of quantification (LLOQ) were similar to those determined by Abbott except for gentamicin for which we determined a LLOQ at 1.22 mg/L while Abbott determined it at 0.5 mg/L. All assays diluted linear and analyte concentrations were not affected by interferences. Concentrations obtained for real samples on the Alinity®c are comparable to those obtained on the Architect®ci. CONCLUSIONS: The analytical validation of a method suitable for therapeutic drug monitoring of drugs on the Alinity®c meets the requirements of European Medicines Agency.


Assuntos
Monitoramento de Medicamentos/instrumentação , Monitoramento de Medicamentos/métodos , Nefelometria e Turbidimetria/instrumentação , Nefelometria e Turbidimetria/métodos , Amicacina/análise , Amicacina/sangue , Automação Laboratorial/instrumentação , Automação Laboratorial/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Gentamicinas/análise , Gentamicinas/sangue , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Fenobarbital/análise , Fenobarbital/sangue , Fenitoína/análise , Fenitoína/sangue , Reprodutibilidade dos Testes , Teofilina/análise , Teofilina/sangue , Ácido Valproico/análise , Ácido Valproico/sangue , Vancomicina/análise , Vancomicina/sangue
9.
Med. clín (Ed. impr.) ; 154(7): 275-278, abr. 2020. graf
Artigo em Espanhol | IBECS | ID: ibc-190912

RESUMO

INTRODUCCIÓN Y OBJETIVOS: La analbuminemia congénita (AAC) (MIM #616000) es una enfermedad autosómica recesiva (prevalencia <1/106) causada por defectos en el gen ALB que implican la ausencia o marcada disminución de la albuminemia. En este artículo, describimos un caso de AAC detectado en nuestro hospital. MATERIAL Y MÉTODOS: Mujer de 42 años con hipoproteinemia e hipoalbuminemia de causa no filiada. El estudio bioquímico se realizó siguiendo las técnicas y los controles de calidad habituales de nuestro laboratorio: albuminemia (colorimetría y nefelometría); electroforesis de proteínas (capilar y gel de agarosa) y análisis molecular del gen ALB (extracción de ADN y amplificación PCR de los 14 exones codificantes más regiones intrónicas adyacentes y secuenciación Sanger). RESULTADOS: Descartadas las causas más frecuentes de hipoalbuminemia, se confirmó la analbuminemia por electroforesis y nefelometría. El estudio molecular del gen ALB evidenció la presencia de la variante c.1289+1G>A (variante Guimarães) en homozigosis. CONCLUSIONES: Este es el primer caso confirmado mediante estudio molecular de AAC en España. La paciente presenta la variante Guimarães descrita previamente en otros 4 pacientes en el mundo


INTRODUCTION AND OBJECTIVES: Congenital analbuminaemia (CCA) (MIM #616000) is an autosomal recessive disorder (prevalence < 1/106) caused by defects in the ALB gene leading to absence or severe reduction of albuminaemia. This paper describes a case of CCA detected and diagnosed in our hospital. MATERIALS AND METHODS: A 42-year old woman showing hypoproteinaemia and hypoalbuminaemia of unknown aetiology. Biochemical study was performed according to routine quality controlled analytical procedures: Albuminaemia (colorimetric and nephelometric methods). Protein electrophoresis (capillary and agarose gel). Molecular study of the ALB gene: DNA extraction, PCR amplification of the 14 coding exons plus adjacent intron regions and Sanger sequencing. RESULTS: After discarding the most common causes of hypoalbuminaemia, the analbuminaemia was confirmed by nephelometry and protein electrophoresis. The proband was found to be homozygous for molecular defect in the ALB gene: variant c.1289+1G>A previously reported as Guimarães variant. CONCLUSIONS: This is the first case of CCA confirmed by molecular study in Spain. The proband shows the Guimarães variant previously described in 4 patients worldwide


Assuntos
Humanos , Feminino , Adulto , Doenças Genéticas Inatas/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Albumina Sérica/genética , Doenças Genéticas Inatas/genética , Eletroforese , Hipoalbuminemia/etiologia , Colorimetria/métodos , Nefelometria e Turbidimetria/métodos , Diagnóstico Diferencial
10.
Clin Ther ; 42(3): 475-485, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32139175

RESUMO

PURPOSE: Imipenem/cilastatin/relebactam has shown efficacy in complicated intra-abdominal and urinary tract infections in the RESTORE IMI-1 study, and it was recently approved by the US Food and Drug Administration. A press release announced that another Phase III study (RESTORE IMI-2) in patients with hospital-acquired and ventilator-associated pneumonia has met the primary end point. Critically ill patients with multidrug-resistant infections are expected to receive several pharmaceutical intravenous drugs while admitted in hospitals, warranting the need for Y-site compatibility studies. This study was conducted to evaluate the physical compatibility of imipenem/cilastatin/relebactam for injection during Y-site administration with common injectable intravenous medications. METHODS: Imipenem/cilastatin/relebactam was prepared to the concentration of 5 mg/mL, and other intravenous tested drugs were reconstituted as per the package inserts. Y-site was simulated as a 2-drug combination by mixing 5 mL of each in a glass tube, with reversing of the order of mixing; physical characteristics were recorded, and pH changes and turbidity were measured at time intervals. FINDINGS: Imipenem/cilastatin/relebactam was found to be compatible with a wide range of intravenous medications, facilitating co-administration with various IV medications. IMPLICATIONS: The compatibility reported is limited to a 2-h observation period in this study to adequately cover imipenem/cilastatin/relebactam infusion time. In addition, it is based on the measured turbidity with no chemical assay of the components of the admixture.


Assuntos
Compostos Azabicíclicos/química , Cilastatina/química , Imipenem/química , Combinação de Medicamentos , Nefelometria e Turbidimetria
11.
Vascular ; 28(4): 457-464, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32212917

RESUMO

OBJECTIVE: Thromboangiitis obliterans is a nonatherosclerotic occlusive disease, affecting small to moderate sized arteries of the upper and lower extremities, leading to progressive inflammation and clot formation. However, the role of humoral and cell-mediated immunity in the development of this disease has not been clearly identified. The present study was intended to investigate the humoral and cellular immune response in patients with Buerger's disease with different disease severity. METHODS: In an observational study, 80 male patients with Buerger's disease were included and categorized into three groups (mild, moderate, and severe) based on clinical manifestations. After blood sampling, cellular phenotypes were determined, and erythrocyte sedimentation rate, immunoglobulins (Ig) A, M, G, and E, as well as C3 and C4 components of the complement system and complement hemolytic activity (CH50) were measured. RESULTS: The mean age of the patient was 42.85 ± 8.39 years. Pulse abnormality, cold intolerance, and claudication were the most common symptoms. Eleven (13.75%), 46 (57.50%), and 23 (28.75%) patients had mild, moderate, and severe symptoms. Regression analyses showed that the presence of severe symptoms was significantly associated with elevated erythrocyte sedimentation rate and C4 levels (p < 0.05). CONCLUSION: Buerger's disease in severe cases was associated with increased erythrocyte sedimentation rate and abnormal C4 levels. The alterations in these inflammatory biomarkers might be due to a secondary inflammatory response to the presence of ulcer or gangrene and the inflammatory process in patients with severe symptoms.


Assuntos
Complemento C4/análise , Eritrócitos/imunologia , Imunidade Celular , Imunidade Humoral , Tromboangiite Obliterante/imunologia , Adulto , Biomarcadores/sangue , Sedimentação Sanguínea , Humanos , Masculino , Pessoa de Meia-Idade , Nefelometria e Turbidimetria , Valor Preditivo dos Testes , Sistema de Registros , Índice de Gravidade de Doença , Tromboangiite Obliterante/sangue , Tromboangiite Obliterante/fisiopatologia , Regulação para Cima
13.
Clin Lab ; 66(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32013355

RESUMO

BACKGROUND: Blood status is closely related to the hemoglobin test results in clinical laboratory. This paper discusses a case of which hemoglobin test results were not interfered by the "milky" blood status. METHODS: Complete Blood Count with Differential (CBC + Diff) was detected for these two specimens with a Sysmex XN-9000. RESULTS: The results of red cell indices for patient I were as follows: red blood cell count (RBC), 5.10 x 1012/L; hematocrit (HCT), 0.455 L/L; hemoglobin (HGB), 167 g/L; mean corpuscular hemoglobin concentration (MCHC), 367 g/L, and triglycerides (TG), 1.59 mmol/L. There was no "turbidity" warning message. However, there was a "turbidity" warning message for patient II and his red cell indices were RBC, 4.74 x 1012/L; HCT, 0.492 L/L; HGB, 182 g/L; MCHC, 370 g/L, and TG, 12.98 mmol/L. After the plasma exchange, there was no "turbidity" warning message for patient I and his red cell indices were RBC, 4.83 x 1012/L; HCT, 0.444 L/L; HGB, 164 g/L; MCHC, 369 g/L which were consistent with the results before the plasma exchange. For patient II, the "turbidity" warning message disappeared and his results were RBC, 3.87 x 1012/L; HCT, 0.398 L/L; HGB, 135 g/L; MCHC, 339 g/L. CONCLUSIONS: Our case provided an explanation of the normal hemoglobin detection results in the visible lipemic specimen for the first time.


Assuntos
Testes Hematológicos/métodos , Testes Hematológicos/normas , Hemoglobinas/análise , Hiperlipidemias/sangue , Lipídeos/química , Humanos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Nefelometria e Turbidimetria
14.
Int J Biol Macromol ; 146: 444-452, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31923486

RESUMO

In this manuscript, lysozyme/κ-carrageenan (LYS-CRG) complexes were prepared and used to encapsulate curcumin. The LYS-CRG complexes demonstrate good encapsulation of curcumin (CUR), and the encapsulation efficiency (EE) and loading capacity (LC) reach 96.2% and 2.31%, respectively. The encapsulated CUR has high antioxidant activity, while the thermal stability and photostability of CUR are also increased. The LYS-CRG complexes could effectively improve the storage stability of CUR and increase its retention rate. In simulated gastric fluid, only 17.91% CUR in the CUR-LYS-CRG complex nanoparticles is released in 3 h, while in the simulated intestinal fluid, the CUR release rate quickly reaches 62.56% in 1.5 h. The release rate tends to be stable within 1.5 h to 3 h and the final release rate reaches 67.23%, suggesting that the formation of CUR-LYS-CRG complex nanoparticles does not affect CUR release in the simulated intestinal fluid.


Assuntos
Carragenina/química , Curcumina/farmacologia , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Muramidase/metabolismo , Nanopartículas/química , Compostos de Bifenilo/química , Preparações de Ação Retardada , Emulsões/química , Depuradores de Radicais Livres/química , Luz , Nefelometria e Turbidimetria , Tamanho da Partícula , Picratos/química
15.
Thromb Haemost ; 120(1): 44-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31752041

RESUMO

Turbidimetry is used to characterize fibrin clot properties. In purified systems, maximum absorbance (MA) directly relates to fibrin fiber cross-sectional area. However, in plasma samples there are discrepancies in the relationships between MA and fibrinogen concentration, fiber diameter, other clot properties, and cardiovascular disease outcomes, which complicate data interpretation. This study aims to advance understanding of MA of plasma clots through testing how well it relates to fundamental dependence on fibrinogen concentration and fiber diameter as predicted by light scattering theory, other clot properties and lifestyle, and biochemical variables. Plasma samples from 30 apparently healthy individuals with a fibrinogen concentration from 2.4 to 6.4 g/L were included. We performed turbidimetry, permeability, scanning electron microscopy, and rheometry on in vitro formed plasma clots. MA correlated more strongly with fibrinogen concentration (r = 0.65; p < 0.001) than with fiber diameter (r = 0.47; p = 0.01), which combined explained only 46% of the MA variance. Of additional variables measured, only low-density lipoprotein cholesterol correlated with MA (r = 0.46; p = 0.01) and clot lysis (r = 0.62; p < 0.0001) but not with fiber diameter or fibrinogen concentration. MA correlated with clot lysis time (r = 0.59; p = 0.001), storage modulus (r = 0.61; p = 0.001), and loss modulus (r = 0.59; p = 0.001), and negatively with clot permeability (r = -0.60; p = 0.001) also after adjustment for fibrinogen concentration and fiber diameter. Increased MA is indicative of a prothrombotic clot phenotype irrespective of fibrinogen concentration. MA is more indicative of overall clot density than of fiber diameter. Other plasma components can alter internal fiber density without altering fiber diameter and should be considered when interpreting MA of plasma samples.


Assuntos
Fibrina/metabolismo , Fibrinogênio/metabolismo , Nefelometria e Turbidimetria/métodos , Trombose/diagnóstico , Idoso , Coagulação Sanguínea/efeitos dos fármacos , Feminino , Fibrina/química , Tempo de Lise do Coágulo de Fibrina , Fibrinólise , Hemostáticos/uso terapêutico , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Nefelometria e Turbidimetria/estatística & dados numéricos , Plasma , Trombose/tratamento farmacológico
16.
Thromb Haemost ; 120(1): 75-82, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733633

RESUMO

BACKGROUND: Despite long-term antiplatelet therapy with aspirin, recurrent cardiovascular events remain common in patients with coronary artery disease (CAD). OBJECTIVE: We aimed to determine whether fibrin network characteristics are predictive of vascular events in patients with stable CAD treated with aspirin monotherapy. METHODS: We included 786 patients with angiographically documented CAD and either prior myocardial infarction, type 2 diabetes mellitus, or both. Median follow-up time was 3 years. At inclusion, fibrin clot properties were evaluated using a turbidimetric assay and the following clot parameters were studied: (1) maximum absorbance, a measure of clot density and fiber thickness; (2) lysis time, assessing fibrinolysis potential; and (3) area under the curve (AUC), a measure of clot formation and lysis. The primary endpoint was the composite of nonfatal myocardial infarction, ischemic stroke, and cardiovascular death. Hazard ratios (HRs) were estimated using multivariable Cox proportional hazards regression. RESULTS: A total of 70 primary endpoints occurred. The primary endpoint occurred more frequently in CAD patients with increased clot AUC (crude HR for first vs. fourth quartile: 2.4 [95% confidence interval 1.2-4.6], p = 0.01). This finding remained significant after adjusting for potential confounders (adjusted HR: 2.4 [1.2-4.8], p = 0.01). Neither clot maximum absorbance nor lysis time showed significant association with future vascular events (adjusted HR for maximum absorbance 1.8 [0.9-3.7]; p = 0.09) and lysis time (1.6 [0.8-3.0]; p = 0.18). CONCLUSION: We demonstrate that increased clot AUC predicts future cardiovascular events in stable CAD patients receiving aspirin monotherapy.


Assuntos
Doença da Artéria Coronariana/diagnóstico , Fibrina/metabolismo , Infarto do Miocárdio/diagnóstico , Idoso , Aspirina/uso terapêutico , Coagulação Sanguínea , Doença da Artéria Coronariana/tratamento farmacológico , Doença da Artéria Coronariana/mortalidade , Fibrinólise , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/mortalidade , Nefelometria e Turbidimetria , Prognóstico , Análise de Sobrevida , Trombose
17.
Comput Methods Programs Biomed ; 183: 105084, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31580969

RESUMO

BACKGROUND AND OBJECTIVE: This paper is focused on the analysis of a method of estimation of the absorption and scattering coefficients of nonhomogeneous two layered structures in time resolved near infrared spectroscopy using method based on cumulative distributions of time of flight of photons. METHODS: The research is based on the analysis of the superposition of cumulative distributions of time of flight of photons. This approach allows for detailed analysis of small variations in characteristics of time of flight of photons caused by an electromagnetic propagation in highly scattering non-homogeneous media. The method presented, based on the variation of statistical minimum distance estimation, is compared to the method of standard curve fitting. It is analyzed by fitting the results obtained from Monte-Carlo simulations of light propagation in the turbid medium to the data from the simulated measurements. RESULTS: The analysis is carried out for a vast range of optical properties of two layered medium in reflectance geometry. CONCLUSIONS: The method allows the estimation of the optical parameters despite the noise in the measured signal, with higher accuracy and generally with smaller number of error function evaluations.


Assuntos
Processamento de Imagem Assistida por Computador , Imagem Óptica , Espectroscopia de Luz Próxima ao Infravermelho , Algoritmos , Encéfalo/diagnóstico por imagem , Simulação por Computador , Radiação Eletromagnética , Humanos , Luz , Método de Monte Carlo , Nefelometria e Turbidimetria , Óptica e Fotônica , Imagens de Fantasmas , Fótons , Reprodutibilidade dos Testes , Espalhamento de Radiação
18.
Appl Environ Microbiol ; 86(2)2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31676479

RESUMO

Previous work has demonstrated that the physical properties of intracellular bacterial gas vesicles (GVs) can be analyzed in vivo using pressure nephelometry. In analyzing the buoyant state of GV-containing cyanobacteria, hydrostatic pressure within a sample cell is increased in a stepwise manner, where the concomitant collapse of GVs due to pressure and the resultant decrease in suspended cells are detected by changes in nephelometric scattering. As the relative pressure at which GVs collapse is a function of turgor pressure and cellular osmotic gradients, pressure nephelometry is a powerful tool for assaying changes in metabolism that affect turgor, such as photosynthetic and osmoregulatory processes. We have developed an updated and automated pressure nephelometer that utilizes visible-infrared (Vis-IR) spectra to accurately quantify GV critical collapse pressure, critical collapse pressure distribution, and cell turgor pressure. Here, using the updated pressure nephelometer and axenic cultures of Microcystis aeruginosa PCC7806, we demonstrate that GV critical collapse pressure is stable during mid-exponential growth phase, introduce pressure-sensitive turbidity as a robust metric for the abundance of gas-vacuolate cyanobacteria, and demonstrate that pressure-sensitive turbidity is a more accurate proxy for abundance and growth than photopigment fluorescence. As cyanobacterium-dominated harmful algal bloom (cyanoHAB) formation is dependent on the constituent cells possessing gas vesicles, characterization of environmental cyanobacteria populations via pressure nephelometry is identified as an underutilized monitoring method. Applications of this instrument focus on physiological and ecological studies of cyanobacteria, for example, cyanoHAB dynamics and the drivers associated with cyanotoxin production in aquatic ecosystems.IMPORTANCE The increased prevalence of bloom-forming cyanobacteria and associated risk of exposure to cyanobacterial toxins through drinking water utilities and recreational waterways are growing public health concerns. Cost-effective, early-detection methodologies specific to cyanobacteria are crucial for mitigating these risks, with a gas vesicle-specific signal offering a number of benefits over photopigment fluorescence, including improved detection limits and discrimination against non-gas-vacuolate phototrophs. Here, we present a multiplexed instrument capable of quantifying the relative abundance of cyanobacteria based on the signal generated from the presence of intracellular gas vesicles specific to bloom-forming cyanobacteria. Additionally, as cell turgor can be measured in vivo via pressure nephelometry, the measurement furnishes information about the internal osmotic pressure of gas-vacuolate cyanobacteria, which relates to the metabolic state of the cell. Together these advances may improve routine waterway monitoring and the mitigation of human health threats due to cyanobacterial blooms.


Assuntos
Cianobactérias/fisiologia , Proliferação Nociva de Algas/fisiologia , Microcystis/fisiologia , Nefelometria e Turbidimetria/métodos , Fitoplâncton/fisiologia , Cianobactérias/crescimento & desenvolvimento , Nefelometria e Turbidimetria/instrumentação
19.
Appl Spectrosc ; 74(3): 261-274, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31397583

RESUMO

An approach binary spectronephelometry (BSN) to perform real-time simultaneous noninvasive in situ physical and chemical analysis of bacterial cultures in fluid media is described. We choose to characterize cultures of Escherichia coli (NC), Pseudomonas aeruginosa (PA), and Shewanella oneidensis (SO) in the specific case of complex media whose Raman spectrum cannot be unambiguously assigned. Nevertheless, organism number density and a measure of the chemical makeup of the fluid medium can be monitored noninvasively, simultaneously, and continuously, despite changing turbidity and medium chemistry. The method involves irradiating a culture in fluid medium in an appropriate vessel (in this case a standard 1 cm cuvette) using a near infrared laser and collecting all the backscattered light from the cuvette, i.e., the Rayleigh-Mie line and the inelastically emitted light which includes unresolved Raman scattered light and fluorescence. Complex "legacy" media contain materials of biological origin whose chemical composition cannot be fully delineated. We independently calibrate this approach to a commonly used reference, optical density at 600 nm (OD600) for characterizing the number density of organisms. We suggest that the total inelastically emitted light could be a measure of the chemical state of a biologically based medium, e.g., lysogeny broth (LB). This approach may be useful in a broad range of basic and applied studies and enterprises that utilize bacterial cultures in any medium or container that permits optical probing in the single scattering limit.


Assuntos
Nefelometria e Turbidimetria/métodos , Espectrometria de Fluorescência/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Análise Espectral Raman/métodos , Algoritmos , Meios de Cultura/análise , Escherichia coli/crescimento & desenvolvimento , Pseudomonas aeruginosa/crescimento & desenvolvimento , Shewanella/crescimento & desenvolvimento
20.
Sci Rep ; 9(1): 19694, 2019 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-31873085

RESUMO

Women with uncomplicated urinary tract infection (UTI) symptoms are commonly treated with empirical antibiotics, resulting in overuse of antibiotics, which promotes antimicrobial resistance. Available diagnostic tools are either not cost-effective or diagnostically sub-optimal. Here, we identified clinical and urinary immunological predictors for UTI diagnosis. We explored 17 clinical and 42 immunological potential predictors for bacterial culture among women with uncomplicated UTI symptoms using random forest or support vector machine coupled with recursive feature elimination. Urine cloudiness was the best performing clinical predictor to rule out (negative likelihood ratio [LR-] = 0.4) and rule in (LR+ = 2.6) UTI. Using a more discriminatory scale to assess cloudiness (turbidity) increased the accuracy of UTI prediction further (LR+ = 4.4). Urinary levels of MMP9, NGAL, CXCL8 and IL-1ß together had a higher LR+ (6.1) and similar LR- (0.4), compared to cloudiness. Varying the bacterial count thresholds for urine culture positivity did not alter best clinical predictor selection, but did affect the number of immunological predictors required for reaching an optimal prediction. We conclude that urine cloudiness is particularly helpful in ruling out negative UTI cases. The identified urinary biomarkers could be used to develop a point of care test for UTI but require further validation.


Assuntos
Biomarcadores/urina , Infecções Urinárias/diagnóstico , Infecções Urinárias/urina , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Diagnóstico por Computador , Feminino , Humanos , Fatores Imunológicos/urina , Interleucina-1beta/urina , Interleucina-8/urina , Funções Verossimilhança , Lipocalina-2/urina , Aprendizado de Máquina , Metaloproteinase 9 da Matriz/urina , Pessoa de Meia-Idade , Nefelometria e Turbidimetria , Testes Imediatos , Máquina de Vetores de Suporte , Infecções Urinárias/imunologia , Adulto Jovem
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