Ultrasonographic Estimation of Total Brain Volume: 3D Reliability and 2D Estimation. Enabling Routine Estimation During NICU Admission in the Preterm Infant

Objectives: The aim of this study is to explore if manually segmented total brain volume (TBV) from 3D ultrasonography (US) is comparable to TBV estimated by magnetic resonance imaging (MRI). We then wanted to test 2D based TBV estimation obtained through three linear axes which would enable monitoring brain growth in the preterm infant during admission. Methods: We included very low birth weight preterm infants admitted to our neonatal intensive care unit (NICU) with normal neuroimaging findings. We measured biparietal diameter, anteroposterior axis, vertical axis from US and MRI and TBV from both MRI and 3D US. We calculated intra- and interobserver agreement within and between techniques using the intraclass correlation coefficient and Bland-Altman methodology. We then developed a multilevel prediction model of TBV based on linear measurements from both US and MRI, compared them and explored how they changed with increasing age. The multilevel prediction model for TBV from linear measures was tested for internal and external validity and we developed a reference table for ease of prediction of TBV. Results: We used measurements obtained from 426 US and 93 MRI scans from 118 patients. We found good intra- and interobserver agreement for all the measurements. US measurements were reliable when compared to MRI, including TBV which achieved excellent agreement with that of MRI [ICC of 0.98 (95% CI 0.96-0.99)]. TBV estimated through 2D measurements of biparietal diameter, anteroposterior axis, and vertical axis was comparable among both techniques. We estimated the population 95% confidence interval for the mean values of biparietal diameter, anteroposterior axis, vertical axis, and total brain volume by post-menstrual age. A TBV prediction table based on the three axes is proposed to enable easy implementation of TBV estimation in routine 2D US during admission in the NICU. Conclusions: US measurements of biparietal diameter, vertical axis, and anteroposterior axis are reliable. TBV segmented through 3D US is comparable to MRI estimated TBV. 2D US accurate estimation of TBV is possible through biparietal diameter, vertical, and anteroposterior axes.This work was supported by the 2017 (PI0052/2017) and 2019 (ITI-0019-2019) ITI-Cadiz integrated territorial initiative for biomedical research European Regional Development Fund (ERDF) 2014-2020. Andalusian Ministry of Health and Families, Spain

Nuclear Magnetic Relaxation in Haemoglobin Deuterated Samples in the Course of the Polymerization Process of Haemoglobin S

Resumen En este trabajo, se investigaron los tiempos de relajación espín-espín del deuterio y del protón a 4 Mz en muestras deuteradas de hemoglobina S, a 36 durante desoxigenación espontánea. La relajación del deuterio muestra un comportamiento sigmoidal relacionado con el proceso de polimerización de la hemoglobina S. La coincidencia entre los comportamientos de la relajación, tanto para protón como para deuterio, nos permitió afirmar, que durante el proceso de aglutinación molecular, los cambios en la en la movilidad molecular son mucho más significativos que los provocados por las variaciones en el acoplamiento cuadrupolar, debido al incremento de los gradientes de campos eléctricos. Palabras clave: polimerización, tiempo de demora, tiempo de correlación. Abstract The deuterium and proton spin-spin relaxation times are investigated at 4 MHz in deuterated samples of hemoglobin S, at 36 ºC and during spontaneous deoxygenation. Deuterium relaxation shows a sigmoidal behaviour related to the Hemoglobin S polymerisation process. The coincidence between deuterium and proton relaxation behaviours allow us to affirm that, during the macromolecular agglutination process, the changes on molecular mobility are more significant than those coming from the variations in the cuadrupolar coupling due to the increase of the internal electric fields gradients

Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau

The microtubule associated protein Tau also interacts with filamentous actin. Here the authors combine biophysical experiments and NMR studies to characterize the structural changes that occur in Tau upon binding to filamentous actin and show that phosphorylation of serine 262 attenuates actin binding of Tau

Estudios de Resonancia Magnética en Anemia de Hematies Falciformes

Magnetic Resonance applications to the study of Sickle Cell Disease are analyzed using classical procedures and Unilateral Magnetic Resonance. Hemoglobin and whole blood samples were obtained from healthy individual and patients with Sickle Cell Anemia to be used as samples. Classical pulse sequence as spin echo and inversion recovery were used in the experimental studies, the STEPR method was used for EPR spectrometric determinations. The results show the possibility of NMR methods to follow the molecular process causing the disease and allow us to present quantitative procedures to estimate the clinical state of the patients and the results of clinical options. We present the Unilateral Magnetic Resonance as a new method to study Sickle Cell disease considering its portability and new possibilities as new image method.En este trabajo se analizan diferentes aplicaciones de la Resonancia Magnética al estudio de la Anemia de Hematíes Falciformes, incluyendo métodos clásicos y la Resonancia Magnética Unilateral. Las muestras de hemoglobina y sangre total fueron obtenidas a partir de individuos saludables y pacientes con Anemia Drepanocítica. Secuencias de pulso clásicas como spin eco e inversión recuperación fueron utilizadas en los estudios experimentales, el método de STEPR fue utilizado para determinaciones espectrofotométricas de Resonancia Paramagnética Electrónica. Los resultados muestran la posibilidad de los métodos de Resonancia Magnética para estudiar el proceso molecular que causa esta enfermedad y nos permite presentar procedimientos cuantitativos para estimar el estado clínico del paciente y evaluar opciones terapéuticas. Presentamos la Resonancia Magnética Unilateral como un nuevo método para estudiar la Anemia Drepanocítica considerando su portabilidad y nuevas posibilidades como método de imagen