RESUMO
Boumans et al. conducted a systematic review and meta-analysis to evaluate the diagnostic accuracy of lung ultrasound (LUS) in acute respiratory distress syndrome (ARDS). The study found that LUS has high specificity (0.942, 95% CI 0.856-0.978) but variable sensitivity (0.631, 95% CI 0.450-0.782) for identifying ARDS-related diffuse lung pathologies. LUS demonstrates comparable or superior performance to chest radiography and CT scans, facilitating rapid bedside diagnosis and management. However, variability in operator experience and interpretation criteria, as well as challenges in detecting mild or early-stage ARDS, remain. The study highlights the need for further research to refine LUS protocols and training, enhancing its application in clinical practice and improving patient outcomes.
Assuntos
Síndrome do Desconforto Respiratório , Ultrassonografia , Humanos , Síndrome do Desconforto Respiratório/fisiopatologia , Síndrome do Desconforto Respiratório/terapia , Ultrassonografia/métodos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Sensibilidade e EspecificidadeRESUMO
The influence of the hydrogen bond formation on the nuclear magnetic resonance parameters has been investigated for the binary (1:1) and ternary (1:2) glycine-HCN complexes in the gas phase using high-level density functional theory with the B3LYP/6-31++G(2d,2p)//B3LYP/6-31++G(d,p) model of quantum chemistry. The calculated isotropic/anisotropic shielding parameters of the isolated glycine and HCN molecules are reported and compared with other theoretical results and experimental measurements. Six different conformations of hydrogen-bonded clusters have considered for both 1:1 and 1:2 glycine-HCN complexes. The isotropic and anisotropic chemical shifts for all the constituent atoms of the complexes have been calculated. The spin-spin coupling constants and the Fermi contact terms have also been analyzed in the context of hydrogen-bond formation.
Assuntos
Glicina/química , Cianeto de Hidrogênio/química , Gases/química , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Teoria QuânticaRESUMO
This research work describes two studies for the classification and characterization of edible oils and its quality parameters through Fourier transform mid infrared spectroscopy (FT-mid-IR) together with chemometric methods. The discrimination of canola, sunflower, corn and soybean oils was investigated using SVM-DA, SIMCA and PLS-DA. Using FT-mid-IR, DPLS was able to classify 100% of the samples from the validation set, but SIMCA and SVM-DA were not. The quality parameters: refraction index and relative density of edible oils were obtained from reference methods. Prediction models for FT-mid-IR spectra were calculated for these quality parameters using partial least squares (PLS) and support vector machines (SVM). Several preprocessing alternatives (first derivative, multiplicative scatter correction, mean centering, and standard normal variate) were investigated. The best result for the refraction index was achieved with SVM as well as for the relative density except when the preprocessing combination of mean centering and first derivative was used. For both of quality parameters, the best results obtained for the figures of merit expressed by the root mean square error of cross validation (RMSECV) and prediction (RMSEP) were equal to 0.0001.
Assuntos
Fenômenos Químicos , Química Orgânica/métodos , Modelos Químicos , Óleos de Plantas/química , Óleos de Plantas/classificação , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Discriminante , Análise dos Mínimos Quadrados , Análise de Componente Principal , Refratometria , Análise de Regressão , Máquina de Vetores de SuporteRESUMO
Near infrared (NIR) spectroscopy and multivariate classification were applied to discriminate soybean oil samples into non-transgenic and transgenic. Principal Component Analysis (PCA) was applied to extract relevant features from the spectral data and to remove the anomalous samples. The best results were obtained when with Support Vectors Machine-Discriminant Analysis (SVM-DA) and Partial Least Squares-Discriminant Analysis (PLS-DA) after mean centering plus multiplicative scatter correction. For SVM-DA the percentage of successful classification was 100% for the training group and 100% and 90% in validation group for non transgenic and transgenic soybean oil samples respectively. For PLS-DA the percentage of successful classification was 95% and 100% in training group for non transgenic and transgenic soybean oil samples respectively and 100% and 80% in validation group for non transgenic and transgenic respectively. The results demonstrate that NIR spectroscopy can provide a rapid, nondestructive and reliable method to distinguish non-transgenic and transgenic soybean oils.
Assuntos
Química Orgânica/métodos , Glycine max/genética , Óleo de Soja/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Análise Discriminante , Análise dos Mínimos Quadrados , Plantas Geneticamente Modificadas , Análise de Componente Principal , Máquina de Vetores de SuporteRESUMO
Petroclival meningiomas are technically challenging lesions. They have a tendency to grow slowly, involve cranial nerves and compress the brainstem and basilar artery, pushing them to the opposite side. Their natural history is marked by clinical deterioration and fatal outcome. They were once considered inoperable lesions; decades ago, mortality rates were higher than 50%. The authors describe 15 petroclival meningiomas treated surgically between 1995 and 2007. The main approaches used were combined anterior petrosectomy and retrosigmoid (3 cases), retrosigmoid (8 cases), and pre-sigmoid and subtemporal (4 cases). The mortality rate was 13.5% due to surgical bed hematoma and brain ischemia. The post-operative complications were hydrocephalus in 2 cases, cerebrospinal fluid leak in 2 cases and infection of surgical flap in one case. Limiting factors for surgical removal are tumor consistency, encasement of brainstem perforators and pre-operative clinical status.
Assuntos
Neoplasias Meníngeas/complicações , Neoplasias Meníngeas/cirurgia , Meningioma/complicações , Meningioma/cirurgia , Procedimentos Neurocirúrgicos/métodos , Osso Petroso/cirurgia , Adulto , Nervos Cranianos/patologia , Nervos Cranianos/cirurgia , Craniotomia/efeitos adversos , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Neoplasias Meníngeas/mortalidade , Meningioma/mortalidade , Pessoa de Meia-Idade , Exame Neurológico , Procedimentos Neurocirúrgicos/efeitos adversos , Osso Petroso/patologia , Complicações Pós-Operatórias , Estudos Retrospectivos , Resultado do TratamentoRESUMO
The activity of PGLa, an antimicrobial peptide isolated from hemocytes of frog skin and its secretions on living Escherichia coli, was investigated by imaging the cells with atomic force microscopy (AFM) in physiological conditions and by measuring its cellular stiffness. The treatment of bacteria with the antimicrobial peptide PGLa in the culture medium had two stages. The first was characterized by the loss of surface stiffness and consequent loss of bacteria topographic features and the formation of micelles probably originating from the disruption of the outer membrane. The formation of outer membrane originated micelles is in agreement with the carpet-like mechanism of action proposed for antimicrobial peptides of the magainin family. The peptide action also resulted in the removal of bacterial pili. In a second stage there was further damage which resulted in total cell rupture. The addition of Mg(2+) ions prior to peptide treatment partially inhibited the effects of PGLa on bacteria. This result suggests that PGLa interacts with the outer membrane by displacing Mg(2+) from LPS, inserting itself into the bilayer and cross-bridging the negative charges of LPS lipids as proposed in the self-promoted pathway mechanism. The peptide effect on the bacteria was compared to the activity of the chelating agent EDTA that damages the bacterial outer membrane by removing Mg(2+) ions.
Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Escherichia coli/efeitos dos fármacos , Microscopia de Força Atômica , Ar , Fenômenos Biomecânicos , Adesão Celular , Ácido Edético/farmacologia , Magnésio/farmacologia , SoluçõesRESUMO
PW2 (HPLKQYWWRPSI) was selected from phage display libraries through an alternative panning method using living sporozoites of Eimeria acervulina as target. Synthetic PW2 shows anticoccidial activity against E. acervulina and Eimeria tenella with very low hemolytic activity. It also displays antifungal activity but no activity against bacteria. We present the solution structure of the PW2 bound to SDS micelles. In the absence of an interface, PW2 is in random coil conformation. In micelles, structural calculation shows that Trp-7 forms the hydrophobic core that is important for the peptide folding. Lys-4, Tyr-6, Trp-8, and Arg-9 are in the same surface, possibly facing the micelle interface. This possibility was supported by the fact that chemical shift differences for these residues were more pronounced when compared with PW2 in water and in SDS. PW2 gains structure upon binding to SDS micelles. Lys-4, Tyr-6, Trp-8, and Arg-9 were found to bind to the micelle. Trp-7, Trp-8, and Arg-9 composed the WW+ consensus found in the sequence of the peptides selected with the phage display technique against E. acervulina sporozoites. This suggested that Trp-7, Trp-8, and Arg-9 are probably key residues not only for the peptide interaction with SDS micelles but also for the interaction with E. acervulina sporozoites surface.
Assuntos
Coccidiostáticos/farmacologia , Biblioteca de Peptídeos , Triptofano/química , Animais , Arginina/química , Aves , Dicroísmo Circular , Eimeria/metabolismo , Concentração de Íons de Hidrogênio , Peptídeos e Proteínas de Sinalização Intercelular , Lisina/química , Espectroscopia de Ressonância Magnética , Micelas , Modelos Moleculares , Peptídeos/química , Conformação Proteica , Dodecilsulfato de Sódio/química , Tirosina/químicaRESUMO
In the present work, we describe the discovery of PW2, a novel peptide presenting in vitro activity against Eimeria acervulina and E. tenella sporozoites. PW2 was selected from phage display (Ph.D.) peptide libraries by an alternative method of panning using living purified E. acervulina sporozoites as targets. Our results showed that the peptide disrupts the sporozoite pellicle, resembling the effect caused by most natural antimicrobial peptides. PW2 peptide was also effective against fungi and showed low activity against Toxoplasma gondii tachyzoites, but no activity against Trypanosoma cruzi, Crithidia fasciculata epimastigotes, and bacteria. Additionally, the parasiticidal concentrations of PW2 produced a very low lytic effect on mammalian and avian cells. The effectiveness against Eimeria sporozoites and the absence of adverse effects to host cells indicates that PW2 may be used as a model to generate new drugs for the control of avian coccidiosis.