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1.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
2.
A case of Rubinstein‐Taybi syndrome associated with growth hormone deficiency in childhood
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Ruiz-Úcar Elena Acín-Gándara Débora Medina-García Manuel Ronda Diego Cruzado Pereira-Pérez Fernando 《Obesity surgery》2022,32(2):569-570
Obesity Surgery - Laparoscopic sleeve gastrectomy (LSG) is increasingly playing a key role in obesity management. Such operations, however, carry complications sometimes including leaks. The... 相似文献
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Zaida Araujo Sietze Brandes Elena Pinelli María A. Bochichio Andrea Palacios Albina Wide Bruno Rivas-Santiago Juan Carlos Jiménez 《Revista do Instituto de Medicina Tropical de S?o Paulo》2015,57(1):47-55
The present study aimed at measuring seropositivities for infection by
Ascaris suum and Toxocara canis using the
excretory/secretory (E/S) antigens from Ascaris suum (AES) and
Toxocara canis (TES) within an indigenous population. In
addition, quantification of cytokine expressions in peripheral blood cells was
determined. A total of 50 Warao indigenous were included; of which 43 were adults and
seven children. In adults, 44.1% were seropositive for both parasites; whereas
children had only seropositivity to one or the other helminth. For ascariosis, the
percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%,
respectively. While that for toxocariosis, the percentage of TES seropositivity in
adults and children was low; 9.3% and 14.3%, respectively. The percentage of
seronegativity was comparable for AES and TES antigens in adults (27.9%) and children
(28.6%). When positive sera were analyzed by Western blotting technique using AES
antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the
TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9,
98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that
Blastocystis hominis, Hymenolepis nana and
Entamoeba coli were the most commonly observed intestinal
parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and
IL-4 expressions showed that there was only a significant increased expression of
IL-4 in indigenous with TES seropositivity (p < 0.002).
Ascaris and Toxocara seropositivity was
prevalent among Warao indigenous. 相似文献
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N. S. Hari Narayana Moorthy Sergio F. Sousa Maria J. Ramos Pedro A. Fernandes 《Medicinal chemistry research》2016,25(7):1340-1357
Farnesyltransferase (FTase) is one of the prenyltransferase family enzymes that catalyse the transfer of 15-membered isoprenoid (farnesyl) moiety to the cysteine of CAAX motif-containing proteins including Rho and Ras family of G proteins. Inhibitors of FTase act as drugs for cancer, malaria, progeria and other diseases. In the present investigation, we have developed two structure-based pharmacophore models from protein–ligand complex (3E33 and 3E37) obtained from the protein data bank. Molecular dynamics (MD) simulations were performed on the complexes, and different conformers of the same complex were generated. These conformers were undergone protein–ligand interaction fingerprint (PLIF) analysis, and the fingerprint bits have been used for structure-based pharmacophore model development. The PLIF results showed that Lys164, Tyr166, TrpB106 and TyrB361 are the major interacting residues in both the complexes. The RMSD and RMSF analyses on the MD-simulated systems showed that the absence of FPP in the complex 3E37 has significant effect in the conformational changes of the ligands. During this conformational change, some interactions between the protein and the ligands are lost, but regained after some simulations (after 2 ns). The structure-based pharmacophore models showed that the hydrophobic and acceptor contours are predominantly present in the models. The pharmacophore models were validated using reference compounds, which significantly identified as HITs with smaller RMSD values. The developed structure-based pharmacophore models are significant, and the methodology used in this study is novel from the existing methods (the original X-ray crystallographic coordination of the ligands is used for the model building). In our study, along with the original coordination of the ligand, different conformers of the same complex (protein–ligand) are used. It concluded that the developed methodology is significant for the virtual screening of novel molecules on different targets. 相似文献