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1.
Sensors (Basel) ; 21(17)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34502576

RESUMO

Within the last few decades, the need for subject authentication has grown steadily, and biometric recognition technology has been established as a reliable alternative to passwords and tokens, offering automatic decisions. However, as unsupervised processes, biometric systems are vulnerable to presentation attacks targeting the capture devices, where presentation attack instruments (PAI) instead of bona fide characteristics are presented. Due to the capture devices being exposed to the public, any person could potentially execute such attacks. In this work, a fingerprint capture device based on thin film transistor (TFT) technology has been modified to additionally acquire the impedances of the presented fingers. Since the conductance of human skin differs from artificial PAIs, those impedance values were used to train a presentation attack detection (PAD) algorithm. Based on a dataset comprising 42 different PAI species, the results showed remarkable performance in detecting most attack presentations with an APCER = 2.89% in a user-friendly scenario specified by a BPCER = 0.2%. However, additional experiments utilising unknown attacks revealed a weakness towards particular PAI species.


Assuntos
Identificação Biométrica , Algoritmos , Biometria , Impedância Elétrica , Dedos , Humanos
2.
Sensors (Basel) ; 21(17)2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34502646

RESUMO

The electro-mechanical impedance (EMI) technique has been applied successfully to detect minor damage in engineering structures including reinforced concrete (RC). However, in the presence of temperature variations, it can cause false alarms in structural health monitoring (SHM) applications. This paper has developed an innovative approach that integrates the EMI methodology with multilevel hierarchical machine learning techniques and the use of fiber Bragg grating (FBG) temperature and strain sensors to evaluate the mechanical performance of RC beams strengthened with near surface mounted (NSM)-fiber reinforced polymer (FRP) under sustained load and varied temperatures. This problem is a real challenge since the bond behavior at the concrete-FRP interface plays a key role in the performance of this type of structure, and additionally, its failure occurs in a brittle and sudden way. The method was validated in a specimen tested over a period of 1.5 years under different conditions of sustained load and temperature. The analysis of the experimental results in an especially complex problem with the proposed approach demonstrated its effectiveness as an SHM method in a combined EMI-FBG framework.


Assuntos
Engenharia , Polímeros , Impedância Elétrica , Aprendizado de Máquina , Temperatura
4.
J Int Med Res ; 49(9): 3000605211031063, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34496645

RESUMO

OBJECTIVE: To evaluate the role of bioimpedance-defined overhydration (BI-OH) parameters in predicting the risk of mortality and cardiovascular (CV) events in patients undergoing dialysis. METHODS: We searched multiple electronic databases for studies investigating BI-OH indicators in the prediction of mortality and CV events through 23 May 2020. We assessed the effect of BI-OH indexes using unadjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Sensitivity analysis was used for each outcome. RESULTS: We included 55 studies with 104,758 patients in the meta-analysis. Extracellular water/total body water (ECW/TBW) >0.4 (HR 5.912, 95% CI: 2.016-17.342), ECW/intracellular water (ICW) for every 0.01 increase (HR 1.041, 95% CI: 1.031-1.051), and OH/ECW >15% (HR 2.722, 95% CI: 2.005-3.439) increased the risk of mortality in patients receiving dialysis. ECW/TBW >0.4 (HR 2.679, 95% CI: 1.345-5.339) and ECW/ICW per increment of 10% (HR 1.032, 95% CI: 1.017-1.047) were associated with an increased risk of CV events in patients undergoing dialysis. A 1-degree increase in phase angle was a protective factor for both mortality (HR 0.676, 95% CI: 0.474-0.879) and CV events (HR 0.736, 95% CI: 0.589-0.920). CONCLUSIONS: BI-OH parameters might be independent predictors for mortality and CV events in patients undergoing dialysis.


Assuntos
Doenças Cardiovasculares , Desequilíbrio Hidroeletrolítico , Impedância Elétrica , Humanos , Diálise Renal/efeitos adversos , Desequilíbrio Hidroeletrolítico/etiologia
5.
Nutrients ; 13(8)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34444895

RESUMO

(1) Background: Early childhood malnutrition may result in increased fat mass (FM) among school-aged children in low- and middle-income countries (LMICs). We explored whether South African children with shorter stature have greater overall and abdominal FM compared to normal stature children. (2) Methods: Baseline assessments of body composition and weight were determined among school-aged children enrolled in a randomized controlled trial in Port Elizabeth, South Africa, using bioelectrical impedance analysis. Multiple linear regression models tested associations of children's height and degree of stunting with FM, fat free mass (FFM), truncal fat mass (TrFM), and truncal fat free mass (TrFFM) overall and by sex. (3) Results: A total of 1287 children (619 girls, 668 boys) were assessed at baseline. Reduced child height was associated with higher FM and lower FFM and TrFFM, but these associations were reversed with increases in height. Girls classified as mildly or moderately/severely stunted had higher FM and TrFM but lower FFM and TrFFM, while no association was found for boys. (4) Conclusions: Our study suggests that efforts to reduce the non-communicable disease burden in LMICs should target growth-impaired children who may have greater overall FM and greater abdominal FM.


Assuntos
Grupo com Ancestrais do Continente Africano/estatística & dados numéricos , Composição Corporal , Estatura , Transtornos do Crescimento/fisiopatologia , Tecido Adiposo , Criança , Impedância Elétrica , Feminino , Transtornos do Crescimento/epidemiologia , Humanos , Modelos Lineares , Masculino , Estado Nutricional , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores Sexuais , África do Sul/epidemiologia
6.
Int J Mol Sci ; 22(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34360894

RESUMO

Disruption of retinal pigment epithelial (RPE) barrier integrity is involved in the pathology of several blinding retinal diseases including age-related macular degeneration (AMD) and diabetic retinopathy (DR), but the underlying causes and pathophysiology are not completely well-defined. Mitochondria dysfunction has often been considered as a potential candidate implicated in such a process. In this study, we aimed to dissect the role of different mitochondrial components; specifically, those of oxidative phosphorylation (OxPhos), in maintaining the barrier functionality of RPE. Electric cell-substrate impedance sensing (ECIS) technology was used to collect multi-frequency electrical impedance data to assess in real-time the barrier formation of the RPE cells. For this purpose, the human retinal pigment epithelial cell line-ARPE-19-was used and treated with varying concentrations of specific mitochondrial inhibitors that target different steps in OxPhos: Rotenone for complex I (the largest protein complex in the electron transport chain (ETC)); oligomycin for ATP synthase; and carbonyl cyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) for uncoupling ATP synthesis from the accompanying ETC. Furthermore, data were modeled using the ECIS-Zθ software to investigate in depth the effects of these inhibitors on three separate barrier parameters: cell-cell interactions (Rb), cell-matrix interactions (α), and the cell membrane capacitance (Cm). The viability of ARPE-19 cells was determined by lactate dehydrogenase (LDH) Cytotoxicity Assay. The ECIS program's modeling demonstrated that FCCP and thus OxPhos uncoupling disrupt the barrier function in the ARPE-19 cells across all three components of the total resistance (Rb, α, and Cm) in a dose-dependent manner. On the other hand, oligomycin and thus ATP synthase inhibition mostly affects the ARPE-19 cells' attachment to their substrate evident by a significant decrease in α resistance in a dose-dependent manner, both at the end and throughout the duration of the experiment. On the contrary, rotenone and complex I inhibition mostly affect the ARPE-19 paracellular resistance Rb in a dose-dependent manner compared to basolateral resistance α or Cm. Our results clearly demonstrate differential roles for different mitochondrial components in maintaining RPE cell functionality in which uncoupling of OxPhos is a major contributing factor to the disruption barrier function. Such differences can be used in investigating gene expression as well as for screening of selective agents that improve the OxPhos coupling efficiency to be used in the therapeutic approach for treating RPE-related retinal diseases.


Assuntos
Barreira Hematorretiniana/metabolismo , Retinopatia Diabética/metabolismo , Células Epiteliais/metabolismo , Degeneração Macular/metabolismo , Mitocôndrias/metabolismo , Fosforilação Oxidativa/efeitos dos fármacos , Epitélio Pigmentado da Retina/metabolismo , Barreira Hematorretiniana/efeitos dos fármacos , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacocinética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Impedância Elétrica , Transporte de Elétrons/efeitos dos fármacos , Inibidores Enzimáticos/farmacocinética , Humanos , Mitocôndrias/efeitos dos fármacos , ATPases Mitocondriais Próton-Translocadoras/antagonistas & inibidores , Oligomicinas/farmacocinética , Epitélio Pigmentado da Retina/efeitos dos fármacos , Rotenona/farmacocinética
7.
Artigo em Russo | MEDLINE | ID: mdl-34380302

RESUMO

Currently, there is a decrease in the total number of organizations for summer recreation of children in the country while the share of organizations of group II of sanitary and epidemiological well-being among them remains at a consistently high level that determines the potential risk of harm to the health of the child population. At the same time, there is an increase in the number of children with a pronounced health-improving effect. So, it becomes necessary to analyze the information content of modern criteria for assessing the effectiveness of health improvement and to search for ways to resolve the noted contradictions. OBJECTIVE: Analysis and scientific and methodological substantiation of modern criteria for assessing the effectiveness of children's health improvement in recreation organizations (camps). MATERIAL AND METHODS: An analysis of the literature data, our own research results' systematization and effectiveness assessment of the health improvement of 195 children aged 10 to 15 years (112 girls and 83 boys) belonging to I and II health groups and vacationers in the inpatient organization of the Samara region in the 2019 summer campaign were carried out. Anthropometric, physio-metric, and bio-impedance metrics were studied in two stages (on the 1st or 2nd day of arrival and 1 day before the camp leaving). In a comparative analysis the differences were considered significant when p<0.05. RESULTS: Stationary rest and recreation organizations in the all-Russian structure of recreation organizations for children account for 5.8%. During staying in the camp, there was a significant decrease in the proportion of girls with underweight (p=0.039); among boys no significant changes were found. The general trend towards a change in the level of physical development is not statistically significant. Bio-impedance analysis revealed only 51.3% of children with changes in indicators characterizing the health-improving effect. The tendencies to change in the proportion of children with different levels of arm muscle strength and lung capacity during the staying in then camp are statistically significant. Correlations were established between muscle strength with basal metabolism (r=0.86) and muscle mass (r=0.86), as well as negative links between average strength and the percentage of adipose tissue (r= -0.52). During the staying in the camp, the 4 cases of acute respiratory infections were registered that did not affect the assessment of the recovery effectiveness. CONCLUSION: In order to assess the health-improving effect among children during one trial in the camp, the leading functional signs are muscle strength of the arms and vital capacity of the lungs. Additional criteria can be the morbidity during the staying in the camp, and in terms of the nutritional status analysis - the results of bio-impedance analysis. To assess the physical development at the beginning of the camp trial, the use of regional regression scales is informative that requires a corresponding explanation in the documents. In turn, the data from the baseline measurements should be used to build individual health measures during the staying in the camp.


Assuntos
Saúde da Criança , Criança , Impedância Elétrica , Feminino , Humanos , Masculino , Federação Russa , Estações do Ano
8.
Artigo em Inglês | MEDLINE | ID: mdl-34444250

RESUMO

Fat mass and fat-free mass have become useful clinical indices in determining healthy growth and physical development during critical periods of childhood and adolescence; however, despite a wide range of nutritional surveillance its study is limited by a lack of reference data. The purpose of this study was to establish sex-specific and age-specific standards for fat mass and fat-free mass in a large sample of Croatian children and adolescents. In this cross-sectional study, we collected data from 12,678 participants aged 11 to 18 years old (mean age ± standard deviation (SD): 14.17 ± 2.25 years; height 164.56 ± 11.31 cm; weight: 57.45 ± 13.73 kg; body mass index: 21.24 ± 3.67 kg/m2; 53% girls). Fat mass and fat-free mass were measured three times by bioelectrical impedance. The Lambda, Mu and Sigma methods were used to create percentile charts for fat mass index (FMI) and fat-free mass index (FFMI; fat mass and fat-free mass divided by height2). Sex and age differences were calculated using an analysis of variance (ANOVA) with post hoc comparisons. Boys had lower FMI (from 2.66 to 3.89) and higher FFMI values (from 16.90 to 17.80) in all age groups, compared to girls (for FMI from 2.79 to 5.17 and for FFMI from 14.50 to 14.90, p < 0.001). In boys, FMI slightly declined until the age of 14, after which an increase from the age of 15 to 18 was observed. In girls, FMI gradually increased from the age of 11 to 18 (p < 0.001). In general, FFMI increased by age in boys [F(7,5440) = 52.674, p < 0.001], while girls had more stable FFMI across all age groups [F(7,7222) = 2.728, p = 0.057]. The newly established sex-specific and age-specific reference data could be used for national surveillance and to screen for children and adolescents with high FMI and low FFMI.


Assuntos
Composição Corporal , Adolescente , Índice de Massa Corporal , Criança , Estudos Transversais , Impedância Elétrica , Feminino , Humanos , Masculino , Padrões de Referência
9.
Sensors (Basel) ; 21(16)2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34451077

RESUMO

Bedside imaging of ventilation and perfusion is a leading application of 2-D medical electrical impedance tomography (EIT), in which dynamic cross-sectional images of the torso are created by numerically solving the inverse problem of computing the conductivity from voltage measurements arising on electrodes due to currents applied on electrodes on the surface. Methods of reconstruction may be direct or iterative. Calderón's method is a direct reconstruction method based on complex geometrical optics solutions to Laplace's equation capable of providing real-time reconstructions in a region of interest. In this paper, the importance of accurate modeling of the electrode location on the body is demonstrated on simulated and experimental data, and a method of including a priori spatial information in dynamic human subject data is presented. The results of accurate electrode modeling and a spatial prior are shown to improve detection of inhomogeneities not included in the prior and to improve the resolution of ventilation and perfusion images in a human subject.


Assuntos
Algoritmos , Tomografia , Impedância Elétrica , Eletrodos , Humanos , Perfusão
10.
Pol Merkur Lekarski ; 49(292): 311-315, 2021 Aug 16.
Artigo em Polonês | MEDLINE | ID: mdl-34464375

RESUMO

The kidney is an organ that maintains the body's sodium and water balance and plays a significant role in blood pressure regulation. Chronic kidney disease (CKD) and a progressive loss of its function, among others, leads to sodium and water retention and, as a consequence, to arterial hypertension. The supply of salt and fluids delivered with the diet significantly affects the cardiovascular system's functioning particularly in hemodialysis patients. The critical element in clinical care is maintaining appropriate water and electrolyte homeostasis. Overhydration is manifested as oedema and blood preassure increase, but a more accurate assessment of subtle variations is possible by measuring bioelectric impedance (BIA), which determines the extracellular water index (ECW). Actions to maintain euvolemia include limiting sodium and fluid intake, regular assessment of "dry" body weight, proper selection of ultrafiltration (UF), correction of sodium concentration, and dialysate temperature.


Assuntos
Nefrologia , Sódio , Impedância Elétrica , Humanos , Diálise Renal/efeitos adversos , Água , Equilíbrio Hidroeletrolítico
11.
Sensors (Basel) ; 21(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34450726

RESUMO

Measurement of cell surface coverage has become a common technique for the assessment of growth behavior of cells. As an indirect measurement method, this can be accomplished by monitoring changes in electrode impedance, which constitutes the basis of electric cell-substrate impedance sensing (ECIS). ECIS typically yields growth curves where impedance is plotted against time, and changes in single cell growth behavior or cell proliferation can be displayed without significantly impacting cell physiology. To provide better comparability of ECIS curves in different experimental settings, we developed a large toolset of R scripts for their transformation and quantification. They allow importing growth curves generated by ECIS systems, edit, transform, graph and analyze them while delivering quantitative data extracted from reference points on the curve. Quantification is implemented through three different curve fit algorithms (smoothing spline, logistic model, segmented regression). From the obtained models, curve reference points such as the first derivative maximum, segmentation knots and area under the curve are then extracted. The scripts were tested for general applicability in real-life cell culture experiments on partly anonymized cell lines, a calibration setup with a cell dilution series of impedance versus seeded cell number and finally IPEC-J2 cells treated with 1% and 5% ethanol.


Assuntos
Técnicas Biossensoriais , Linhagem Celular , Proliferação de Células , Impedância Elétrica , Eletrodos
12.
Sensors (Basel) ; 21(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34450979

RESUMO

Electromagnetic eddy current sensors are commonly used to identify and quantify the surface notches of metals. However, the unintentional tilt of eddy current sensors affects results of size profiling, particularly for the depth profiling. In this paper, based on the eddy current thin-skin regime, a revised algorithm has been proposed for the analytical voltage or impedance of a tilted driver-pickup eddy current sensor scanning across a long ideal notch. Considering the resolution of the measurement, the bespoke driver-pickup, also termed as transmitter-receiver (T-R) sensor is designed with a small mean radius of 1 mm. In addition, the T-R sensor is connected to the electromagnetic instrument and controlled by a scanning stage with high spatial travel resolution, with a limit of 0.2 µm and selected as 0.25 mm. Experiments were conducted for imaging of an aluminium sheet with seven machined long notches of different depths using T-R sensor under different tilt angles. By fitting the measured voltage (both real and imaginary part) with proposed analytical algorithms, the depth profiling of notches is less affected by the tilt angle of sensors. From the results, the depth of notches can be retrieved within a deviation of 10% for tilt angles up to 60 degrees.


Assuntos
Algoritmos , Impedância Elétrica
13.
Sensors (Basel) ; 21(16)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34450995

RESUMO

Essential quality features of pressure sensors are, among other accuracy-related factors, measurement range, operating temperature, and long-term stability. In this work, these features are optimized for a capacitive pressure sensor with a measurement range of 10 bars. The sensor consists of a metal membrane, which is connected to a PCB and a digital capacitive readout. To optimize the performance, different methods for the joining process are studied. Transient liquid phase bonding (TLP bonding), reactive joining, silver sintering, and electric resistance welding are compared by measurements of the characteristic curves and long-term measurements at maximum pressure. A scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDX) analysis was used to examine the quality of the joints. The evaluation of the characteristic curves shows the smallest measurement errors for TLP bonding and sintering. For welding and sintering, no statistically significant long-term drift was measured. In terms of equipment costs, reactive joining and sintering are most favorable. With low material costs and short process times, electric resistance welding offers ideal conditions for mass production.


Assuntos
Prata , Soldagem , Impedância Elétrica , Temperatura
14.
Langmuir ; 37(35): 10538-10546, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34432473

RESUMO

Several researchers have synthesized graphitic carbon nitride (GCN) from various precursors and attached it to electrode substrates after exfoliation under different conditions and have reported inconsistent data on electrochemical impedance, electroactive surface areas, and electrocatalytic activity. Thus, the present study aims to study the same systematically in addition to morphology after modifying GCN on the GC substrate from different exfoliation times in water assisted by sonication. The GCN was prepared from urea by bulk condensation pyrolysis and then attached to the GC substrate by drop casting to study its morphology, electrochemical impedance, and electrocatalytic activity with respect to exfoliation. The SEM image of a GCN-modified GC plate after 15 and 30 min of exfoliation shows bulky structure whereas thin sheets of GCN were noticed after 120 min of exfoliation. On the other hand, broken sheets were observed when GCN was coated from beyond 120 min of exfoliation. The electrochemical impedance studies show that the charge transfer resistance (RCT) of GCN modified from 15 and 30 min of exfoliation was higher than that for the bare GC electrode. However, it started to decrease while increasing the exfoliation time, and 1.8 kΩ was obtained after 120 min of exfoliation. The RCT value was again increased to 3.2 and 5.0 kΩ for GCN coated after 150 and 180 min of exfoliation, respectively. The electroactive surface area (EASA) of GCN modified by 15 and 30 min of exfoliation was less than that of the bare GC electrode, whereas it was 3.8-fold higher for GCN coated from 120 min of exfoliation. The electrocatalytic activity of the GC electrodes modified with GCN was then tested by studying ascorbic acid (AA) and dopamine (DA) oxidation and reduction of hydrogen peroxide (HP). Among the different exfoliation times, GCN modified from 120 min of exfoliation displayed the highest electrocatalytic activity toward AA, DA, and HP. This was attributed to its higher EASA and lower charge-transfer resistance.


Assuntos
Carbono , Técnicas Eletroquímicas , Impedância Elétrica , Eletrodos , Grafite , Compostos de Nitrogênio , Água
15.
Anal Chem ; 93(34): 11765-11774, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34387479

RESUMO

Microelectrodes are widely used for neural signal analysis because they can record high-resolution signals. In general, the smaller the size of the microelectrode for obtaining a high-resolution signal, the higher the impedance and noise value of the electrodes. Therefore, to improve the signal-to-noise ratio (SNR) of neural signals, it is important to develop microelectrodes with low impedance and noise. In this research, an Au hierarchical nanostructure (AHN) was deposited to improve the electrochemical surface area (ECSA) of a microelectrode. Au nanostructures on different scales were deposited on the electrode surface in a hierarchical structure using an electrochemical deposition method. The AHN-modified microelectrode exhibited an average of 80% improvement in impedance compared to a bare microelectrode. Through electrochemical impedance spectroscopy analysis and impedance equivalent circuit modeling, the increase in the ECSA due to the AHN was confirmed. After evaluating the cell cytotoxicity of the AHN-modified microelectrode through an in vitro test, neural signals from rats were obtained in in vivo experiments. The AHN-modified microelectrode exhibited an approximate 9.79 dB improvement in SNR compared to the bare microelectrode. This surface modification technology is a post-treatment strategy used for existing fabricated electrodes, so it can be applied to microelectrode arrays and nerve electrodes made from various structures and materials.


Assuntos
Nanoestruturas , Animais , Espectroscopia Dielétrica , Impedância Elétrica , Microeletrodos , Ratos , Razão Sinal-Ruído
16.
Artigo em Inglês | MEDLINE | ID: mdl-34379593

RESUMO

Functional electrical stimulation (FES) is often used, typically in an open-loop manner, to restore paralyzed motor function for daily living activities. Several feedback control strategies have been developed to improve the performance and usability of FES-evoked movement. However, most of them have been position controllers, while the control strategy for human movement has been known as impedance modulation. Moreover, few studies have attempted to use antagonistic co-contraction for FES feedback control despite its expected benefits, such as enhanced stability and performance and better rehabilitation outcome. In this paper, we propose a robust impedance controller for FES that can adjust the intrinsic joint stiffness using co-contraction. It consists of an impedance control law based on time-delay estimation to compensate for the nonlinear uncertain joint dynamics and an antagonistic muscle co-contraction allocator to address the intrinsic joint stiffness caused by the co-contraction. The proposed controller was implemented on the ankle joints of five healthy subjects to simulate a standing balance situation. The results verified that the proposed controller can achieve desired impedance accurately by adjusting the intrinsic stiffness that stems from the change in the amount of co-contraction (up to 48.4% better impedance achievement with high desired stiffness).


Assuntos
Articulação do Tornozelo , Contração Muscular , Impedância Elétrica , Estimulação Elétrica , Humanos , Músculo Esquelético , Músculos
17.
Molecules ; 26(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34443567

RESUMO

Redox-active iron generates reactive oxygen species that can cause oxidative organ dysfunction. Thus, the anti-oxidative systems in the body and certain dietary antioxidants, such as anthocyanins, are needed to control oxidative stress. We aimed to investigate the effects of dielectric barrier discharge (DBD) plasma technology in the preparation of Riceberry™ rice flour (PRBF) on iron-induced oxidative stress in mice. PRBF using plasma technology was rich in anthocyanins, mainly cyanidine-3-glucoside and peonidine-3-glucoside. PRBF (5 mg AE/mg) lowered WBC numbers in iron dextran (FeDex)-loaded mice and served as evidence of the reversal of erythrocyte superoxide dismutase activity, plasma total antioxidant capacity, and plasma and liver thiobarbituric acid-reactive substances in the loading mice. Consequently, the PRBF treatment was observed to be more effective than NAC treatment. PRBF would be a powerful supplementary and therapeutic antioxidant product that is understood to be more potent than NAC in ameliorating the effects of iron-induced oxidative stress.


Assuntos
Antocianinas/análise , Antioxidantes/farmacologia , Farinha/análise , Ferro/efeitos adversos , Oryza/química , Estresse Oxidativo/efeitos dos fármacos , Gases em Plasma/química , Animais , Impedância Elétrica , Camundongos
18.
Nutrients ; 13(7)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34371860

RESUMO

Identification of low muscle mass becomes increasingly relevant due to its prognostic value in cancer patients. In clinical practice, mid-upper arm muscle circumference (MAMC) and bioelectrical impedance analysis (BIA) are often used to assess muscle mass. For muscle-mass assessment, computed tomography (CT) is considered as reference standard. We investigated concordance between CT, BIA, and MAMC, diagnostic accuracy of MAMC, and BIA to detect low muscle mass and their relation with the clinical outcome malnutrition provided with the Patient-Generated Subjective Global Assessment Short Form (PG-SGA SF). This cross-sectional study included adult patients with advanced esophageal and gastrointestinal cancer. BIA, MAMC, and PG-SGA-SF were performed. Routine CT-scans were used to quantify psoas muscle index (PMI) and skeletal muscle area. Good concordance was found between CTPMI and both BIAFFMI (fat free mass index) (ICC 0.73), and BIAASMI (appendicular skeletal muscle index) (ICC 0.69) but not with MAMC (ICC 0.37). BIAFFMI (94%), BIAASMI (86%), and MAMC (86%) showed high specificity but low sensitivity. PG-SGA-SF modestly correlated with all muscle-mass measures (ranging from -0.17 to -0.43). Of all patients with low muscle mass, 62% were also classified with a PG-SGA-SF score of ≥4 points. Although CT remains the first choice, since both BIA and MAMC are easy to perform by dieticians, they have the potential to be used to detect low muscle mass in clinical practice.


Assuntos
Antropometria/métodos , Impedância Elétrica , Músculo Esquelético/fisiopatologia , Avaliação Nutricional , Sarcopenia/diagnóstico , Idoso , Braço/diagnóstico por imagem , Braço/fisiopatologia , Índice de Massa Corporal , Estudos Transversais , Neoplasias Esofágicas/complicações , Neoplasias Esofágicas/fisiopatologia , Feminino , Neoplasias Gastrointestinais/complicações , Neoplasias Gastrointestinais/fisiopatologia , Humanos , Masculino , Desnutrição/complicações , Desnutrição/fisiopatologia , Pessoa de Meia-Idade , Músculo Esquelético/diagnóstico por imagem , Estado Nutricional , Estudos Prospectivos , Reprodutibilidade dos Testes , Sarcopenia/etiologia , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
19.
Nutrients ; 13(7)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34371863

RESUMO

Introduction: The accumulation of visceral abdominal tissue (VAT) seems to be a hallmark feature of abdominal obesity and substantially contributes to metabolic abnormalities. There are numerous factors that make the body-mass index (BMI) a suboptimal measure of adiposity. The visceral adiposity index (VAI) may be considered a simple surrogate marker of visceral adipose tissue dysfunction. However, the evidence comparing general to visceral adiposity in CAD is scarce. Therefore, we have set out to investigate visceral adiposity in relation to general adiposity in patients with stable CAD. Material and methods: A total of 204 patients with stable CAD hospitalized in the Department of Medicine and the Department of Geriatrics entered the study. Based on the VAI-defined adipose tissue dysfunction (ATD) types, the study population (N = 204) was divided into four groups: (1) no ATD (N = 66), (2) mild ATD (N = 50), (3) moderate ATD (N = 48), and (4) severe ATD (N = 40). Nutritional status was assessed using the Controlling Nutritional Status (CONUT) score. Results: Patients with moderate and severe ATD were the youngest (median 67 years), yet their metabolic age was the oldest (median 80 and 84 years, respectively). CONUT scores were similar across all four study groups. The VAI had only a modest positive correlation with BMI (r = 0.59 p < 0.01) and body adiposity index (BAI) (r = 0.40 p < 0.01). There was no correlation between VAI and CONUT scores. There was high variability in the distribution of BMI-defined weight categories across all four types of ATD. A total of 75% of patients with normal nutritional status had some form of ATD, and one-third of patients with moderate or severe malnutrition did not have any ATD (p = 0.008). In contrast, 55-60% of patients with mild, moderate, or severe ATD had normal nutritional status (p = 0.008). ROC analysis demonstrated that BMI and BAI have poor predictive value in determining no ATD. Both BMI (AUC 0.78 p < 0.0001) and BAI (AUC 0.66 p = 0.003) had strong predictive value for determining severe ATD (the difference between AUC 0.12 being p = 0.0002). However, BMI predicted mild ATD and severe ATD better than BAI. Conclusions: ATD and malnutrition were common in patients with CAD. Notably, this study has shown a high rate of misclassification of visceral ATD via BMI and BAI. In addition, we demonstrated that the majority of patients with normal nutritional status had some form of ATD and as much as one-third of patients with moderate or severe malnutrition did not have any ATD. These findings have important clinical ramifications for everyday practice regarding the line between health and disease in the context of malnutrition in terms of body composition and visceral ATD, which are significant for developing an accurate definition of the standards for the intensity of clinical interventions.


Assuntos
Adiposidade , Doença da Artéria Coronariana/fisiopatologia , Gordura Intra-Abdominal/fisiopatologia , Estado Nutricional , Obesidade Abdominal/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Antropometria , Biomarcadores/análise , Índice de Massa Corporal , Doença da Artéria Coronariana/etiologia , Impedância Elétrica , Feminino , Avaliação Geriátrica , Humanos , Pacientes Internados/estatística & dados numéricos , Masculino , Avaliação Nutricional , Obesidade Abdominal/complicações , Reprodutibilidade dos Testes
20.
Nutrients ; 13(7)2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34371806

RESUMO

BACKGROUND AND AIM: Sarcopenia is considered an important risk factor for morbidity and mortality in liver cirrhosis. Beta-hydroxy-beta-methylbutyrate (HMB) has the potential to increase muscle mass and performance by stimulating protein synthesis and reducing muscle catabolism. The present study aimed at evaluating the effect of HMB supplementation on muscle mass and function in patients with liver cirrhosis. Changes in frailty during the study were also estimated, and the safety of HMB supplementation was verified. METHODS: This is a randomized, single-blind, placebo-controlled pilot trial. Twenty-four patients (14 HMB and 10 placebo) affected by liver cirrhosis were enrolled in the study. Each patient received dedicated counseling, which included nutrition and physical activity recommendations for chronic liver disease patients. Patients were randomized to receive 3 g/day of HMB or placebo (sorbitol powder) for 12 consecutive weeks. A diet interview, anthropometry, electrical bioimpedance analysis (BIA), quadriceps ultrasound, physical performance battery, Liver Frailty Index (LFI), and cognitive tests were completed at enrolment (T0), at 12 weeks (T1), and 24 weeks after enrolment (T2). RESULTS: At baseline, the two groups were similar in demography, severity of liver disease, muscle mass, muscle function, and cognitive tests. LFI at baseline was higher in patients in the HMB group vs. those in the placebo group (4.1 ± 0.4 vs. 3.4 ± 0.6, p < 0.01). After treatment, a statistically significant increase in muscle function was seen in the HMB group (chair stand test: 14.2 ± 5 s vs. 11.7 ± 2.6 s, p < 0.05; six-minute walk test: 361.8 ± 68 m vs. 409.4 ± 58 m, p < 0.05). Quadriceps muscle mass measured by ultrasound also increased (4.9 ± 1.8 vs. 5.4 ± 1.8 mm, p < 0.05) after HMB, while LFI decreased (4.1 ± 0.4 vs. 3.7 ± 0.4, p < 0.05). HMB was well tolerated by patients, and no adverse events were documented. CONCLUSIONS: Our study suggests the efficacy of 12-week beta-hydroxy-beta-methylbutyrate supplementation in promoting improvements in muscle performance in compensated cirrhotic patients. LFI was also ameliorated. Further studies with a greater number of patients are required to reinforce this hypothesis.


Assuntos
Suplementos Nutricionais , Cirrose Hepática/terapia , Força Muscular/efeitos dos fármacos , Sarcopenia/prevenção & controle , Valeratos/administração & dosagem , Antropometria , Impedância Elétrica , Exercício Físico/fisiologia , Feminino , Fragilidade/etiologia , Fragilidade/prevenção & controle , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/efeitos dos fármacos , Projetos Piloto , Sarcopenia/etiologia , Método Simples-Cego , Resultado do Tratamento
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