Publicações

@article{nokey,

title = {Teste de Pureza Radioquímica em Serviços de Medicina Nuclear: Calibrador de Doses Versus Contador Gama Tipo Poço},

author = {Ana Paula Marques da Costa and Sergio Querino Brunetto and Daniel Massaro Onusic and Celso Dario Ramos},

doi = {https://doi.org/10.29384/rbfm.2018.v12.n2.p30-38},

year  = {2023},

date = {2023-12-20},

journal = {Revista Brasileira De Física Médica},

volume = {12},

issue = {2},

pages = {30-38},

abstract = {O uso do radionuclídeo tecnécio-99m ligado a diversos fármacos é de suma importância na medicina nuclear, devido às suas características físico-químicas e radiológicas. Dentro dos serviços, é necessário um controle de qualidade de marcação eficaz, confiável e reprodutível visando eficácia do procedimento para que não exista concentração indesejável do material radioativo em outros órgãos além daqueles de interesse, devido às falhas da marcação. Um dos controles empregados nos serviços de medicina nuclear brasileiros é conhecido como determinação da pureza radioquímica (DPR), feito pela técnica de cromatografia em papel (coluna ascendente) e as aferições das atividades presentes nas amostras são feitas no medidor de atividades conhecido, também, como calibrador de doses. Este equipamento é eficiente sob o ponto de vista de aferir as atividades das alíquotas de radiofármacos administradas aos pacientes, entretanto, para avaliar a DPR são utilizadas atividades da ordem de milionésimo das administradas aos pacientes e, nessa faixa de atividade, supõe-se que o equipamento necessita de caracterizações e condições específicas para garantir a eficácia deste controle. O método padrão ouro para a aferição da DPR utiliza o contador gama tipo poço, entretanto, no Brasil o número de serviços de medicina nuclear com este tipo de equipamento é pequeno. Assim, o trabalho visou comparar os valores de eficiência obtidos nestes dois equipamentos. Na comparação, utilizou-se do teste não paramétrico de Wilcoxon com valor de significância (p-value) de 0,05 e não se encontrou diferenças significativas entre as medidas feitas com os equipamentos. Foram também determinadas às condições confiáveis para a utilização do medidor de atividades nas faixas de atividade empregas na DPR e as condições para que a radiação de fundo (background) do equipamento seja mínima a fim de não interferir na quantificação do teste cromatográfico.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Influence of brain region of interest location for apparent diffusion coefficient maps calculation for reference values to be used in the in vivo characterization of brain tumors in magnetic resonance images},

author = {Edna Marina de Souza and Gabriela Castellano and Eduardo Tavares Costa},

doi = {https://doi.org/10.29384/rbfm.2011.v5.n1.p89-92},

year  = {2023},

date = {2023-10-27},

urldate = {2023-10-27},

journal = {Revista Brasileira De Física Médica},

volume = {5},

issue = {1},

pages = {89–92},

abstract = {In general, pathologic processes, such as neoplasic cell changes, tend to alter the magnitude of structural organization by destruction or reorganization of membranous elements or by a change in cellularity. These changes will also have an impact on proton mobility, which can be followed up by DWI (diffusion weighted magnetic resonance imaging). From DWI is obtained the ADC (apparent diffusion coefficient) map, which is a representation of the magnitude of water diffusion at the points of a given region of interest (ROI). The purpose of this study was to assess the variation of ADC values in different brain ROIs of normal subjects, using a computer tool previously developed. The aim of this assessment was to verify whether ADC values could be used to differentiate between normal subjects and patients with multiform glioblastoma (a high-grade glioma) and meningioma. ADC maps were calculated for 10 controls, 10 patients with glioblastoma and 10 with meningioma. For controls, mean ADC values were calculated for 10 different ROIs, located in the same places where the tumors were present in the patients. These values were then averaged over ROIs and over subjects, giving a mean ADC value of (8.65±0.98)x10-4 mm2 /s. The mean ADC values found for brain tumors were (5.03±0.67) x10-4 mm2 /s for meningioma and (2.83±0.45)x10-4 mm2 /s for glioblastoma. We concluded that the ROIs used for computing brain ADC values for controls were not essential for the estimation of normal reference ADC values to be used in the differentiation between these types of tumors and healthy brain tissue},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35696826,

title = {Effects of light finger touch on the regularity of center-of-pressure fluctuations during quiet bipedal and single-leg postural tasks},

author = {Jéssica Rodrigues Lara and Cristiano Rocha da Silva and Felipe Fava de Lima and Marcos Camargo da Silva and André Fabio Kohn and Leonardo Abdala Elias and Fernando Henrique Magalhães},

doi = {10.1016/j.gaitpost.2022.05.036},

issn = {1879-2219},

year  = {2022},

date = {2022-07-01},

journal = {Gait Posture},

volume = {96},

pages = {203--209},

abstract = {BACKGROUND: The use of extra sources of sensory information associated with light fingertip touch to enhance postural steadiness has been associated with increased attentional demands, whereas the regularity of center of pressure (COP) fluctuations has been interpreted as a marker of the amount of attention invested in posture control.



RESEARCH QUESTION: This study addressed whether increased attentional demands associated with postural tasks involving light finger touch might be reflected by measures of COP regularity.



METHODS: The experiments involved quiet bipedal stance (n = 8 participants) and single-legged stance (n = 14 participants). Each participant was instructed to stand as quietly as possible on a force plate, either touching an external rigid surface (applied force < 1 N, light touch condition), or not (no touch condition). Postural steadiness was assessed by traditional COP measurements (COP Area, RMS, and velocity), whereas the regularity of postural sway was based on estimates of the sample entropy (SaEn) of the COP time series.



RESULTS: Traditional parameters of postural sway and COP regularity (inversely related to SaEn COP measurements) were reduced during the touch conditions as compared to the no-touch conditions, for both bipedal quiet stance and single-legged stance. Decreased COP regularity with light touch was mainly reflected in the direction of the largest postural sway (i.e. in the sagittal plane for bipedal stance and in the frontal plane for single-legged stance).



SIGNIFICANCE: The present results suggest that actively touching an external surface with the fingertip, besides increasing postural steadiness, generated an externally oriented (presumably cognitive-dependent) focus of attention, so that participants invested less attention on the postural task per se (as suggested by increased SaEn), which might be associated with a more "automatic" control of posture.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34802707,

title = {Influence of central and peripheral motor unit properties on isometric muscle force entropy: A computer simulation study},

author = {Jakob Dideriksen and Leonardo Abdala Elias and Ellen Pereira Zambalde and Carina Marconi Germer and Ricardo Gonçalves Molinari and Francesco Negro},

doi = {10.1016/j.jbiomech.2021.110866},

issn = {1873-2380},

year  = {2022},

date = {2022-06-01},

journal = {J Biomech},

volume = {139},

pages = {110866},

abstract = {Approximate entropy of isometric force is a popular measure to characterize behavioral changes across muscle contraction conditions. The degree to which force entropy characterizes the randomness of the motor control strategy, however, is not known. In this study, we used a computational model to investigate the correlation between approximate entropy of the synaptic input to a motor neuron pool, the neural drive to muscle (cumulative spike train; CST), and the force. This comparison was made across several simulation conditions, that included different synaptic command signal bandwidths, motor neuron pool sizes, and muscle contractile properties. The results indicated that although force entropy to some degree reflects the entropy of the synaptic command to motor neurons, it is biased by changes in motor unit properties. As a consequence, there was a low correlation between approximate entropy of force and the motor neuron input signal across all simulation conditions (r = 0.13). Therefore, force entropy should only be used to compare motor control strategies across conditions where motor neuron properties can be assumed to be maintained. Instead, we recommend that the entropy of the descending motor commands should be estimated from CSTs comprising spike trains of multiple motor units.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35489088,

title = {Developmental differences in myocardial transmembrane Na transport: implications for excitability and Na handling},

author = {Natália Ferreira Oshiyama and Ana H M Pereira and Alisson C Cardoso and Kleber G Franchini and José Wilson Magalhães Bassani and Rosana Almada Bassani},

doi = {10.1113/JP282661},

issn = {1469-7793},

year  = {2022},

date = {2022-06-01},

urldate = {2022-06-01},

journal = {J Physiol},

volume = {600},

number = {11},

pages = {2651--2667},

abstract = {Little is currently known about possible developmental changes in myocardial Na handling, which may have impact on cell excitability and Ca content. Resting intracellular Na concentration ([Na ] ), measured in freshly isolated rat ventricular myocytes with CoroNa green, was not significantly different in neonates (3-5 days old) and adults, but electrical stimulation caused marked [Na ] rise only in neonates. Inhibition of L-type Ca current by CdCl abolished not only systolic Ca transients, but also activity-dependent intracellular Na accumulation in immature cells. This indicates that the main Na influx pathway during activity is the Na /Ca exchanger, rather than voltage-dependent Na current (I ), which was not affected by CdCl . In immature myocytes, I density was two-fold greater, inactivation was faster, and the current peak occurred at less negative transmembrane potential (E ) than in adults. Na channel steady-state activation and inactivation curves in neonates showed a rightward shift, which should increase channel availability at diastolic E , but also require greater depolarization for excitation, which was observed experimentally and reproduced in computer simulations. Ventricular mRNA levels of Na 1.1, Na 1.4 and Na 1.5 pore-forming isoforms were greater in neonate ventricles, while a decrease was seen for the β1 subunit. Both molecular and biophysical changes in the channel profile may contribute to the differences in I density and voltage-dependence, and also to the less negative threshold E , in neonates compared to adults. The apparently lower excitability in immature ventricle may confer protection against the development of spontaneous activity in this tissue. KEY POINTS: Previous studies showed that myocardial preparations from immature rats are less sensitive to electrical field stimulation than adult preparations. Freshly isolated ventricular myocytes from neonatal rats showed lower excitability than adult cells, e.g. less negative threshold membrane potential and greater membrane depolarization required for action potential triggering. In addition to differences in mRNA levels for Na channel isoforms and greater Na current (I ) density, Na channel voltage-dependence was shifted to the right in immature myocytes, which seems to be sufficient to decrease excitability, according to computer simulations. Only in neonatal myocytes did cyclic activity promote marked cytosolic Na accumulation, which was prevented by abolition of systolic Ca transients by blockade of Ca currents. Developmental changes in I may account for the difference in action potential initiation parameters, but not for cytosolic Na accumulation, which seems to be due mainly to Na /Ca exchanger-mediated Na influx.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Case Study on the Removal of Blinking Artifact in Electroencephalogram Signals via Stochastic Filtering},

author = {Rebecca Fernandes Ribeiro and Victor Baptista Frencl and Leonardo Abdala Elias and João Bosco Ribeiro do Val },

doi = {https://doi.org/10.1007/s40313-021-00890-y},

year  = {2022},

date = {2022-01-12},

journal = {Journal of Control, Automation and Electrical Systems},

volume = {33},

pages = {1319–1328},

abstract = {The presence of physiological artifacts in electroencephalogram (EEG) signals is common and detrimental to experimental or clinical analysis. This paper presents a case study where we develop an algorithm based on stochastic filtering to remove blinking artifacts. For this case study, the dynamic system was defined by combining two autoregressive models, the first one represents the EEG signal, and the second one represents the blinking artifact. Some applications use stochastic methods to remove artifacts, so in this paper we apply the stochastic filtering via Kalman filter, that makes possible to remove blinking artifacts from single-channel EEG recordings, as long as the electrooculogram (EOG) signal was available. The method applies to a case study with actual artifacts and simulated artifacts for comparison. The measure of performance utilized is the estimated power spectral density (PSD). The results show that the proposed method could remove blinking artifacts without introducing significant distortions in the EEG signal.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35646854,

title = {High-Resolution Magic-Angle Spinning NMR Spectroscopy for Evaluation of Cell Shielding by Virucidal Composites Based on Biogenic Silver Nanoparticles, Flexible Cellulose Nanofibers and Graphene Oxide},

author = {Danijela Stanisic and Guilherme C F Cruz and Leonardo Abdala Elias and Junko Tsukamoto and Clarice W Arns and Douglas Soares da Silva and Stanislav Mochkalev and Raluca Savu and Ljubica Tasic},

doi = {10.3389/fbioe.2022.858156},

issn = {2296-4185},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Front Bioeng Biotechnol},

volume = {10},

pages = {858156},

abstract = {Antiviral and non-toxic effects of silver nanoparticles onto  cells infected with coronavirus were evaluated in this study using High-Resolution Magic-Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) spectroscopy. Silver nanoparticles were designed and synthesized using an orange flavonoid-hesperetin (HST)-for reduction of silver(I) and stabilization of as obtained nanoparticles. The bio-inspired process is a simple, clean, and sustainable way to synthesize biogenic silver nanoparticles (AgNP@HST) with diameters of ∼20 nm and low zeta potential (-40 mV), with great colloidal stability monitored for 2 years. The nanoparticles were used for the fabrication of two types of antiviral materials: colloids (AgNP@HST spray) and 3D flexible nanostructured composites. The composites, decorated with AgNP@HST (0.05 mmol L), were made using cellulose nanofibers (CNF) obtained from orange peel and graphene oxide (GO), being denominated CNF@GO@AgNP@HST. Both materials showed high virucidal activity against coronaviruses in cell infection  models and successfully inhibited the viral activity in cells. HR-MAS H-NMR technique was used for determining nanomaterials' effects on living cells and their influences on metabolic pathways, as well as to study viral effects on cells. It was proven that none of the manufactured materials showed toxicity towards the intact cells used. Furthermore, viral infection was reverted when cells, infected with the coronavirus, were treated using the as-fabricated nanomaterials. These significant results open possibilities for antiviral application of 3D flexible nanostructured composite such as packaging papers and filters for facial masks, while the colloidal AgNP@HST spray can be used for disinfecting surfaces, as well as a nasal, mouth, and eye spray.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36590063,

title = {Effects of voluntary contraction on the soleus H-reflex of different amplitudes in healthy young adults and in the elderly},

author = {Leandra Batista-Ferreira and Natielle Ferreira Rabelo and Gabriel Menezes da Cruz and Juliana Nunes de Almeida Costa and Leonardo Abdala Elias and Rinaldo André Mezzarane},

doi = {10.3389/fnhum.2022.1039242},

issn = {1662-5161},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Front Hum Neurosci},

volume = {16},

pages = {1039242},

abstract = {A number of H-reflex studies used a moderate steady voluntary contraction in an attempt to keep the motoneuron pool excitability relatively constant. However, it is not clear whether the voluntary muscle activation itself represents a confounding factor for the elderly, as a few ongoing mechanisms of reflex modulation might be compromised. Further, it is well-known that the amount of either inhibition or facilitation from a given conditioning depends on the size of the test H-reflex. The present study aimed at evaluating the effects of voluntary contraction over a wide range of reflex amplitudes. A significant reflex facilitation during an isometric voluntary contraction of the soleus muscle (15% of the maximal voluntary isometric contraction-MVC) was found for both young adults and the elderly ( < 0.05), regardless of their test reflex amplitudes (considering the ascending limb of the H-reflex recruitment curve-RC). No significant difference was detected in the level of reflex facilitation between groups for all the amplitude parameters extracted from the RC. Simulations with a computational model of the motoneuron pool driven by stationary descending commands yielded qualitatively similar amount of reflex facilitation, as compared to human experiments. Both the experimental and modeling results suggest that possible age-related differences in spinal cord mechanisms do not significantly influence the reflex modulation during a moderate voluntary muscle activation. Therefore, a background voluntary contraction of the ankle extensors (e.g., similar to the one necessary to maintain upright stance) can be used in experiments designed to compare the RCs of both populations. Finally, in an attempt to elucidate the controversy around changes in the direct motor response (M-wave) during contraction, the maximum M-wave (Mmax) was compared between groups and conditions. It was found that the Mmax significantly increases ( < 0.05) during contraction and decreases ( < 0.05) with age arguably due to muscle fiber shortening and motoneuron loss, respectively.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Construção de um “Dispositivo Colimador” para câmara de cintilação (SPECT) de aplicação in vivo para realização de exames in vitro na prática de Medicina Nuclear},

author = {Daniel Massaro Onusic and Sérgio Querino Brunetto and Celso Darío Ramos},

doi = {https://doi.org/10.15392/bjrs.v8i1.1068},

year  = {2021},

date = {2021-11-28},

urldate = {2021-11-28},

journal = {Brazilian Journal of Radiation Sciences},

volume = {8},

issue = {1},

abstract = {Este trabalho consistiu no desenvolvimento de um dispositivo de baixo custo para testes e protocolos de exames de medicina nuclear in vitro. Foi desenvolvido e validado inicialmente para medir a taxa de filtração glomerular (TFG) com EDTA-51Cr usando apenas uma câmera de cintilação. O dispositivo consiste de 5 cilindros de chumbo (com tampas) fixados perpendicularmente e espaçadamente sobre uma placa de chumbo, que ao ser acoplado na câmara de cintilação torna-se equivalente a um contador-gama tipo poço, com sensibilidade de 300Bq. Esse dispositivo foi testado para as quantidades usuais de EDTA-51Cr das amostras de plasma sanguíneo de 8 pacientes (6 homens, 2 mulheres, idades de 43-68 anos, média 54 anos) que fizeram o exame de modo convencional. Resultados: Os valores de TFG obtidos com o método convencional e com o dispositivo variaram respectivamente, de 27 a 73 ml/min/1,73m2 (média 56,7±14,0) e de 31 a 82 ml/min/1,73m2 (média 60,9±14,5), expressando uma correlação de r=0,9010 e p=0,5628 (95% de confiança). Conclusão: O dispositivo proposto é uma alternativa confiável ao uso do “Contador Gama Tipo Poço” convencional para medir a TFG usando o método EDTA-51Cr. Devido ao seu custo muito baixo, tem o potencial de promover o uso deste procedimento em qualquer serviço de medicina nuclear que possua uma câmera de cintilação. Esta tecnologia foi depositada no Instituto Nacional de Propriedade Industrial (INPI) sob o processo de patente BR:10.2015.020347-0.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Data-Driven Biophysical Computational Model of Parkinson’s Disease Based on Marmoset Monkeys},

author = {Caetano M. Ranieri and Jhielson M. Pimentel and Marcelo R. Romano and Leonardo Abdala Elias and Roseli A. F. Romero and Michael A. Lones and Mariana F. P. Araujo and Patricia A. Vargas and Renan C. Moioli},

doi = {10.1109/ACCESS.2021.3108682},

issn = {2169-3536},

year  = {2021},

date = {2021-08-30},

urldate = {2021-08-30},

journal = {IEEE Access },

volume = {9},

pages = {122548 - 122567},

abstract = {In this work we propose a new biophysical computational model of brain regions relevant to Parkinson's Disease (PD) based on local field potential data collected from the brain of marmoset monkeys. PD is a neurodegenerative disorder, linked to the death of dopaminergic neurons at the substantia nigra pars compacta, which affects the normal dynamics of the basal ganglia-thalamus-cortex (BG-T-C) neuronal circuit of the brain. Although there are multiple mechanisms underlying the disease, a complete description of those mechanisms and molecular pathogenesis are still missing, and there is still no cure. To address this gap, computational models that resemble neurobiological aspects found in animal models have been proposed. In our model, we performed a data-driven approach in which a set of biologically constrained parameters is optimised using differential evolution. Evolved models successfully resembled spectral signatures of local field potentials and single-neuron mean firing rates from healthy and parkinsonian marmoset brain data. This is the first computational model of PD based on simultaneous electrophysiological recordings from seven brain regions of Marmoset monkeys. Results indicate that the proposed model may facilitate the investigation of the mechanisms of PD and eventually support the development of new therapies. The DE method could also be applied to other computational neuroscience problems in which biological data is used to fit multi-scale models of brain circuits.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34236246,

title = {Surface EMG cross talk quantified at the motor unit population level for muscles of the hand, thigh, and calf},

author = {Carina Marconi Germer and Dario Farina and Leonardo Abdala Elias and Stefano Nuccio and François Hug and Alessandro Del Vecchio},

doi = {10.1152/japplphysiol.01041.2020},

issn = {1522-1601},

year  = {2021},

date = {2021-08-01},

urldate = {2021-08-01},

journal = {J Appl Physiol (1985)},

volume = {131},

number = {2},

pages = {808--820},

abstract = {Cross talk is an important source of error in interpreting surface electromyography (EMG) signals. Here, we aimed at characterizing cross talk for three groups of synergistic muscles by the identification of individual motor unit action potentials. Moreover, we explored whether spatial filtering (single and double differential) of the EMG signals influences the level of cross talk. Three experiments were conducted. Participants (total 25) performed isometric contractions at 10% of the maximal voluntary contraction (MVC) with digit muscles and knee extensors and at 30% MVC with plantar flexors. High-density surface EMG signals were recorded and decomposed into motor unit spike trains. For each muscle, we quantified the cross talk induced to neighboring muscles and the level of contamination by the nearby muscle activity. We also estimated the influence of cross talk on the EMG power spectrum and intermuscular correlation. Most motor units (80%) generated significant cross-talk signals to neighboring muscle EMG in monopolar recording mode, but this proportion decreased with spatial filtering (50% and 42% for single and double differential, respectively). Cross talk induced overestimations of intermuscular correlation and has a small effect on the EMG power spectrum, which indicates that cross talk is not reduced with high-pass temporal filtering. Conversely, spatial filtering reduced the cross-talk magnitude and the overestimations of intermuscular correlation, confirming to be an effective and simple technique to reduce cross talk. This paper presents a new method for the identification and quantification of cross talk at the motor unit level and clarifies the influence of cross talk on EMG interpretation for muscles with different anatomy. We proposed a new method for the identification and quantification of cross talk at the motor unit level. We show that surface EMG cross talk can lead to physiological misinterpretations of EMG signals such as overestimations in the muscle activity and intermuscular correlation. Cross talk had little influence on the EMG power spectrum, which indicates that conventional temporal filtering cannot minimize cross talk. Spatial filter (single and double differential) effectively reduces but not abolish cross talk.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid33596528,

title = {Adipose tissue radiodensity: A new prognostic biomarker in people with multiple myeloma},

author = {Ademar Dantas da Cunha and Marina Nogueira Silveira and Maria Emília Seren Takahashi and Edna Marina de Souza and Camila Mosci and Celso Dario Ramos and Sandra Regina Brambilla and Fernando Vieira Pericole and Carla M Prado and Maria Carolina Santos Mendes and José Barreto Campello Carvalheira},

doi = {10.1016/j.nut.2021.111141},

issn = {1873-1244},

year  = {2021},

date = {2021-06-01},

journal = {Nutrition},

volume = {86},

pages = {111141},

abstract = {OBJECTIVES: Standard prognostic markers based on individual characteristics of individuals with multiple myeloma (MM) remain scarce. Body-composition features have often been associated with survival outcomes in different cancers. However, the association of adipose tissue radiodensity with MM prognosis has not yet, to our knowledge, been explored.



METHODS: Computed tomography at the third lumbar vertebra was used for body-composition analysis, including adipose tissue radiodensity, in 91 people with MM. Additionally, fludeoxyglucose F 18 (F-FDG) positron emission tomography was used to assess adipose tissue F-FDG uptake. Proinflammatory cytokine and adipokine levels were measured.



RESULTS: Event-free survival and overall survival were both shorter in participants with high subcutaneous adipose tissue (SAT) radiodensity. Those in the highest SAT radiodensity tertile had an independently higher risk for both overall survival (hazard ratio, 4.55; 95% confidence interval, 1.26-16.44; P = 0.036) and event-free survival (hazard ratio, 3.08; 95% confidence interval, 1.02-9.27; P = 0.035). Importantly, higher SAT radiodensity was significantly correlated with increased F-FDG adipose tissue uptake and proinflammatory cytokine (tumor necrosis factor and interleukin-6) levels, and with decreased leptin levels.



CONCLUSIONS: SAT radiodensity may serve as a biomarker to predict host-related metabolic and proinflammatory milieu, which ultimately correlates with MM prognosis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid33632534,

title = {Visceral adipose tissue glucose uptake is linked to prognosis in multiple myeloma patients: An exploratory study},

author = {Ademar Dantas da Cunha Júnior and Marina Nogueira Silveira and Maria Emilia Seren Takahashi and Edna Marina de Souza and Camila Mosci and Celso Dario Ramos and Sandra Regina Brambilla and Fernando Vieira Pericole and Carla M Prado and Maria Carolina Santos Mendes and José Barreto Campello Carvalheira},

doi = {10.1016/j.clnu.2021.02.010},

issn = {1532-1983},

year  = {2021},

date = {2021-06-01},

journal = {Clin Nutr},

volume = {40},

number = {6},

pages = {4075--4084},

abstract = {BACKGROUND & AIMS: The use of computerized tomography to opportunistically assess body composition has highlighted abnormalities such as low muscle mass and high adiposity may be hidden conditions in cancer patients. However, the role of skeletal muscle (SM), subcutaneous (SAT) and visceral (VAT) adipose tissue glucose uptake measured by F-fluorodeoxyglucose (F-FDG) positron emission tomography (PET)-CT on patient prognostication is unclear.



METHODS: Patients with multiple myeloma (MM) with satisfactory image frame for assessing body composition and for semi-quantification of SM, SAT and VAT glucose uptakes were included. Plasmatic pro-inflammatory cytokine and adipokine levels were measured.



RESULTS: High VAT mean standardized uptake value (SUV) at baseline was associated with shorter event-free survival (EFS) (hazard ratio [HR]: 7.89; 95% confidence interval [CI], 1.58-39.30; P = 0.012) and overall survival (OS) (HR, 15.24; 95% CI, 2.69-86.30; P = 0.002) among patients with newly diagnosed MM, even after adjustment for covariates. The highest tertile of VAT SUV was significantly correlated with worse MM-EFS (HR for the highest vs the lowest tertile 3.71; 95% CI, 1.22-10.56; P = 0.035) and mortality (HR, 4.41; 95% CI, 1.28-12.77; P = 0.019). Notably, patients with higher VAT SUV presented with lower VAT area, VAT index, higher SAT SUV, and higher number of individuals with visceral obesity (all P < 0.01). Additionally, we found a negative correlation between VAT mean SUV with leptin (R = 0.20, P = 0.003); no correlations were detected between VAT mean SUV and resistin, tumor necrosis factor (TNF) or interleukin (IL)-6.



CONCLUSIONS: Functional VAT activity estimated by F-FDG PET-CT is a relevant prognostic factor in MM patients, specifically, a higher VAT SUV might be an early biomarker of cancer cachexia in these patients.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid33556894,

title = {The ForceLAB simulator: Application to the comparison of current models of cardiomyocyte contraction},

author = {Robson Rodrigues da Silva and Osias Baptista de Souza Filho and José Wilson Magalhães Bassani and Rosana Almada Bassani},

doi = {10.1016/j.compbiomed.2021.104240},

issn = {1879-0534},

year  = {2021},

date = {2021-04-01},

journal = {Comput Biol Med},

volume = {131},

pages = {104240},

abstract = {Mathematical models are useful tools in the study of physiological phenomena. However, due to differences in assumptions and formulations, discrepancy in simulations may occur. Among the models for cardiomyocyte contraction based on Huxley's cross-bridge cycling, those proposed by Negroni and Lascano (NL) and Rice et al. (RWH) are the most frequently used. This study was aimed at developing a computational tool, ForceLAB, which allows implementing different contraction models and modifying several functional parameters. As an application, electrically-stimulated twitches triggered by an equal Ca input and steady-state force x pCa relationship (pCa = -log of the molar free Ca concentration) simulated with the NL and RWH models were compared. The equilibrium Ca-troponin C (TnC) dissociation constant (K) was modified by changing either the association (k) or the dissociation (k) rate constant. With the NL model, raising K by either maneuver decreased monotonically twitch amplitude and duration, as expected. With the RWH model, in contrast, the same K variation caused increase or decrease of peak force depending on which rate constant was modified. Additionally, force x pCa curves simulated using Ca binding constants estimated in cardiomyocytes bearing wild-type and mutated TnC were compared to curves previously determined in permeabilized fibers. Mutations increased k and k, and decreased K. Both models produced curves fairly comparable to the experimental ones, although sensitivity to Ca was greater, especially with RWH model. The NL model reproduced slightly better the qualitative changes associated with the mutations. It is expected that this tool can be useful for teaching and investigation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}