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https://www.readbyqxmd.com/read/27930673/dopamine-neurons-change-the-type-of-excitability-in-response-to-stimuli
#1
Ekaterina O Morozova, Denis Zakharov, Boris S Gutkin, Christopher C Lapish, Alexey Kuznetsov
The dynamics of neuronal excitability determine the neuron's response to stimuli, its synchronization and resonance properties and, ultimately, the computations it performs in the brain. We investigated the dynamical mechanisms underlying the excitability type of dopamine (DA) neurons, using a conductance-based biophysical model, and its regulation by intrinsic and synaptic currents. Calibrating the model to reproduce low frequency tonic firing results in N-methyl-D-aspartate (NMDA) excitation balanced by γ-Aminobutyric acid (GABA)-mediated inhibition and leads to type I excitable behavior characterized by a continuous decrease in firing frequency in response to hyperpolarizing currents...
December 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27925050/fetal-thrombotic-vasculopathy-a-case-report-and-literature-review
#2
Ana Berquo Peleja, Silvio Martinelli, Renata Lopes Ribeiro, Roberto Eduardo Bittar, Regina Schultz, Rossana Pulcineli Vieira Francisco
Introduction: Fetal thrombotic vasculopathy is a recently described placental alteration with varying degrees of involvement and often associated with adverse perinatal outcomes. The diagnosis is made histologically and therefore is postnatal, which makes it a challenge in clinical practice. Method: Case report and review of literature on the subject. Results: The present case refers to a pregnant woman presenting fetal growth restriction, with poor obstetrical past, and sent late to our service...
October 2016: Revista da Associação Médica Brasileira
https://www.readbyqxmd.com/read/27907857/membrane-effects-of-dihydropyrimidine-analogues-with-larvicidal-activity
#3
Mariela E Sánchez-Borzone, Maria E Mariani, Virginia Miguel, Raquel M Gleiser, Bharti Odhav, Katharigatta N Venugopala, Daniel A García
Two recently synthesized dihydropyrimidines (DHPMs) analogues have demonstrated larvicide and repellent activity against Anopheles arabiensis. DHPMs high lipophilicity suggests that these compounds may interact directly with the membrane and modify their biophysical properties. The purpose of the present study was to characterize the interaction of both compounds with artificial membranes. Changes on the properties of DPPC films were studied using Langmuir monolayers. The presence of DHPMs in the subphase modified the interfacial characteristics of DPPC compression isotherms, causing the expansion of the monolayer, inducing the disappearance of DPPC phase transition and increasing the molecular packing of the film...
November 24, 2016: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/27865408/progesterone-and-ultrasonographic-changes-during-aglepristone-or-cloprosternol-treatment-in-queens-at-21-to-22-or-35-to-38%C3%A2-days-of-pregnancy
#4
M C García Mitacek, M C Bonaura, R G Praderio, R Nuñez Favre, R L de la Sota, M A Stornelli
Progesterone (P4) is a requirement for pregnancy development. Previous reports observed a maximal value of serum P4 concentration on 21 days after the first mating after which it slowly declines throughout the rest of pregnancy. Ultrasound examination should be performed to ensure that pregnancy interruption is complete. Limited information is available on the ultrasonic appearance of conceptuses during pregnancy termination in cats The objective was to study serum P4 concentration and ultrasonographic changes during aglepristone (ALI) or cloprostenol (CLO) treatment and to evaluate the fertility after treatment...
January 15, 2017: Theriogenology
https://www.readbyqxmd.com/read/27853033/performance-of-waist-circumference-and-proposed-cutoff-levels-for-defining-overweight-and-obesity-in-nigerians
#5
Christian I Okafor, Taiwo H Raimi, Ibrahim D Gezawa, Anas A Sabir, Ofem Enang, Fabian Puepet, Olufemi A Fasanmade, Esther N Ofoegbu, Olatunde Odusan
BACKGROUND: Waist circumference (WC) is a simple tool for measuring central obesity in routine clinic settings. Gender- and ethnic-specific optimal cutoff points for WC are encouraged for populations lacking such data. OBJECTIVES: To derive WC cutoff values, predictive of overweight and obesity in Nigerians and to evaluate the performance of currently recommended values. SUBJECTS AND METHODS: Apparently, healthy urban dwellers from six cities spread across Nigeria were selected for this cross-sectional study...
October 2016: Annals of African Medicine
https://www.readbyqxmd.com/read/27845653/non-stationary-rician-noise-estimation-in-parallel-mri-using-a-single-image-a-variance-stabilizing-approach
#6
Tomasz Pieciak, Santiago Aja-Fernandez, Gonzalo Vegas Sanchez-Ferrero
Parallel magnetic resonance imaging (pMRI) techniques have gained a great importance both in research and clinical communities recently since they considerably accelerate the image acquisition process. However, the image reconstruction algorithms needed to correct the subsampling artifacts affect the nature of noise, i.e. it becomes non-stationary. Some methods have been proposed in the literature dealing with the non-stationary noise in pMRI. However, their performance depends on information not usually available such as multiple acquisitions, receiver noise matrices, sensitivity coil profiles, reconstruction coefficients, or even biophysical models of the data...
November 7, 2016: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/27809226/biophysical-properties-and-motility-of-human-mature-dendritic-cells-deteriorated-by-vascular-endothelial-growth-factor-through-cytoskeleton-remodeling
#7
Zu-Quan Hu, Hui Xue, Jin-Hua Long, Yun Wang, Yi Jia, Wei Qiu, Jing Zhou, Zong-Yao Wen, Wei-Juan Yao, Zhu Zeng
Dendritic cells (DCs), the most potent antigen-presenting cells, play a central role in the initiation, regulation, and maintenance of the immune responses. Vascular endothelial growth factor (VEGF) is one of the important cytokines in the tumor microenvironment (TME) and can inhibit the differentiation and functional maturation of DCs. To elucidate the potential mechanisms of DC dysfunction induced by VEGF, the effects of VEGF on the biophysical characteristics and motility of human mature DCs (mDCs) were investigated...
October 31, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27806573/discovery-of-age-related-protein-folding-stability-differences-in-the-mouse-brain-proteome
#8
Julia H Roberts, Fang Liu, Jaret M Karnuta, Michael C Fitzgerald
Described here is the application of thermodynamic stability measurements to study age-related differences in the protein folding and stability of proteins in a rodent model of ageing. Thermodynamic stability profiles were generated for 809 proteins in brain cell lysates from mice, aged 6- (n=7) and 18-months (n=9) using the Stability of Proteins from Rates of Oxidation (SPROX) technique. The biological variability of the protein stability measurements was low and within the experimental error of SPROX. A total of 83 protein hits was detected with age-related stability differences in the brain samples...
November 2, 2016: Journal of Proteome Research
https://www.readbyqxmd.com/read/27798601/multiple-dynamin-family-members-collaborate-to-drive-mitochondrial-division
#9
Jason E Lee, Laura M Westrate, Haoxi Wu, Cynthia Page, Gia K Voeltz
Mitochondria cannot be generated de novo; they must grow, replicate their genome, and divide in order to be inherited by each daughter cell during mitosis. Mitochondrial division is a structural challenge that requires the substantial remodelling of membrane morphology. Although division factors differ across organisms, the need for multiple constriction steps and a dynamin-related protein (Drp1, Dnm1 in yeast) has been conserved. In mammalian cells, mitochondrial division has been shown to proceed with at least two sequential constriction steps: the endoplasmic reticulum and actin must first collaborate to generate constrictions suitable for Drp1 assembly on the mitochondrial outer membrane; Drp1 then further constricts membranes until mitochondrial fission occurs...
December 1, 2016: Nature
https://www.readbyqxmd.com/read/27783707/pluripotent-and-multipotent-stem-cells-display-distinct-hypoxic-mirna-expression-profiles
#10
Rahul Agrawal, Tina P Dale, Mohammed A Al-Zubaidi, Prit Benny Malgulwar, Nicholas R Forsyth, Ritu Kulshreshtha
MicroRNAs are reported to have a crucial role in the regulation of self-renewal and differentiation of stem cells. Hypoxia has been identified as a key biophysical element of the stem cell culture milieu however, the link between hypoxia and miRNA expression in stem cells remains poorly understood. We therefore explored miRNA expression in hypoxic human embryonic and mesenchymal stem cells (hESCs and hMSCs). A total of 50 and 76 miRNAs were differentially regulated by hypoxia (2% O2) in hESCs and hMSCs, respectively, with a negligible overlap of only three miRNAs...
2016: PloS One
https://www.readbyqxmd.com/read/27783504/the-remarkable-character-of-porphobilinogen-synthase
#11
Eileen K Jaffe
Porphobilinogen synthase (PBGS), also known as 5-aminolevulinate dehydratase, is an essential enzyme in the biosynthesis of all tetrapyrroles, which function in respiration, photosynthesis, and methanogenesis. Throughout evolution, PBGS adapted to a diversity of cellular niches and evolved to use an unusual variety of metal ions both for catalytic function and to control protein multimerization. With regard to the active site, some PBGSs require Zn(2+); a subset of those, including human PBGS, contain a constellation of cysteine residues that acts as a sink for the environmental toxin Pb(2+)...
October 26, 2016: Accounts of Chemical Research
https://www.readbyqxmd.com/read/27780118/molecular-hybridization-approach-of-bio-potent-cu-ii-zn-ii-complexes-derived-from-n-o-donor-bidentate-imine-scaffolds-synthesis-spectral-human-serum-albumin-binding-antioxidant-and-antibacterial-studies
#12
Mohammad Shakir, Summaiya Hanif, Md Fazle Alam, Hina Younus
Novel bio-relevant monometallic Schiff base complexes of the type, [Cu(L(1))2] (1), [Zn(L(1))2]·2H2O (2), [Cu(L(2))2]·2H2O (3) and [Zn(L(2))2]·H2O (4) [L(1)(E)-3-(((3-chloro-4-hydroxyphenyl)imino)methyl)naphthalen-2-ol and L(2)(E)-2-chloro-4-((1-(5-chloro-2-hydroxyphenyl)ethylidene)amino)phenol] were synthesized and characterized. A comparative account of analytical, spectroscopic (FT-IR, (1)H and (13)C NMR, Mass, UV-vis and EPR), thermal (TGA/DTA), XRD and SEM studies revealed a correlation between the structure and function of these biologically active molecular entities...
October 11, 2016: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/27775236/half-life-extension-of-biopharmaceuticals-using-chemical-methods-alternatives-to-pegylation
#13
REVIEW
Søren B van Witteloostuijn, Søren L Pedersen, Knud J Jensen
Peptides and proteins constitute a vast pool of excellent drug candidates. Evolution has equipped these molecules with superior drug-like properties such as high specificity and potency. However, native peptides and proteins suffer from an inadequate pharmacokinetic profile, and their outstanding pharmacological potential can only be realized if this issue is addressed during drug development. To overcome this challenge, a variety of half-life extension techniques relying on covalent chemical modification have been developed...
November 21, 2016: ChemMedChem
https://www.readbyqxmd.com/read/27761972/suppressing-the-epimerization-of-endothioamide-peptides-during-fmoc-t-bu-based-solid-phase-peptide-synthesis
#14
Somnath Mukherjee, Jayanta Chatterjee
Despite a number of intriguing utilities associated with thioamide-containing peptides and proteins in the context of biophysics, pharmacology and chemical biology, it has hitherto remained as one of the underexplored territories of peptidomimetics. The synthesis of long mono to multiply substituted endothioamide peptides is invariably accompanied with severe epimerization, oxoamide formation and various other undesired side reactions, resulting in messy product profiles. This has completely restrained their use as novel chemical tools for biological studies...
November 2016: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/27759400/a-general-model-of-hindered-diffusion
#15
Shaltiel Eloul, Richard G Compton
The diffusion of a particle from bulk solution is slowed as it moves close to an adsorbing surface. A general model is reported which is easily applied by theoreticians and experimentalists. Specifically, it is shown here that in general and regardless of the space size, the magnitude of the effect of hindered diffusion on the flux is a property of the diffusion layer thickness. We quantify and explain the effect. Predictions of concentration profiles show that a 'hindered diffusion layer' is formed near the adsorbing surface within the diffusion layer, observed even when the particle radius is just a 0...
October 19, 2016: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/27748562/disentangling-the-photochemical-salinity-tolerance-in-aster-tripolium-l-connecting-biophysical-traits-with-changes-in-fatty-acid-composition
#16
B Duarte, M T Cabrita, C Gameiro, A R Matos, R Godinho, J C Marques, I Caçador
A profound analysis of A. tripolium photochemical traits under salinity exposure is lacking in the literature, with very few references focusing on its fatty acid profile role in photophysiology. To address this, the deep photochemical processes were evaluated by Pulse Amplitude Modulated (PAM) Fluorometry coupled with a discrimination of its leaf fatty acid profile. Plants exposed to 125-250 mm NaCl showed higher photochemical light harvesting efficiencies and lower energy dissipation rates. under higher NaCl exposure, there is evident damage of the oxygen evolving complexes (OECs)...
October 17, 2016: Plant Biology
https://www.readbyqxmd.com/read/27737557/structure-function-profile-of-mmpl3-the-essential-mycolic-acid-transporter-from-mycobacterium-tuberculosis
#17
Juan Manuel Belardinelli, Amira Yazidi, Liang Yang, Lucien Fabre, Wei Li, Benoit Jacques, Shiva Kumar Angala, Isabelle Rouiller, Helen I Zgurskaya, Jurgen Sygusch, Mary Jackson
The MmpL family of proteins translocates complex (glyco)lipids and siderophores across the cell envelope of mycobacteria and closely related Corynebacteriaceae and plays important roles in the biogenesis of the outer membrane of these organisms. Despite their significance in the physiology and virulence of Mycobacterium tuberculosis, and from the perspective of developing novel antituberculosis agents, little is known about their structure and mechanism of translocation. In this study, the essential mycobacterial mycolic acid transporter, MmpL3, and its orthologue in Corynebacterium glutamicum, CmpL1, were investigated as prototypical MmpL proteins to gain insight into the transmembrane topology, tertiary and quaternary structures, and functional regions of this transporter family...
October 14, 2016: ACS Infectious Diseases
https://www.readbyqxmd.com/read/27733170/development-of-a-mathematical-model-to-estimate-intra-tumor-oxygen-concentrations-through-multi-parametric-imaging
#18
Chung-Wein Lee, Keith M Stantz
BACKGROUND: Tumor hypoxia is involved in every stage of solid tumor development: formation, progression, metastasis, and apoptosis. Two types of hypoxia exist in tumors-chronic hypoxia and acute hypoxia. Recent studies indicate that the regional hypoxia kinetics is closely linked to metastasis and therapeutic responses, but regional hypoxia kinetics is hard to measure. We propose a novel approach to determine the local pO2 by fusing the parameters obtained from in vivo functional imaging through the use of a modified multivariate Krogh model...
October 12, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/27731889/a-plant-oil-containing-ph-4-emulsion-improves-epidermal-barrier-structure-and-enhances-ceramide-levels-in-aged-skin
#19
J Blaak, D Dähnhardt, S Dähnhardt-Pfeiffer, S Bielfeldt, K-P Wilhelm, R Wohlfart, P Staib
OBJECTIVE: Xerosis is a serious problem among the very old. It is a dermatological challenge caused by significant alterations in stratum corneum (SC) function and structure. Two negative changes in aged skin are (i) the enhanced skin surface pH and (ii) the altered SC lipid content, composition and ordering. METHODS: Therefore, we investigated the way in which an acidic skin care product with different plant oils affects SC function, structure and lipid profile in older subjects with dry skin...
October 12, 2016: International Journal of Cosmetic Science
https://www.readbyqxmd.com/read/27679813/using-a-semi-automated-strategy-to-develop-multi-compartment-models-that-predict-biophysical-properties-of-interneuron-specific-3-is3-cells-in-hippocampus
#20
Alexandre Guet-McCreight, Olivier Camiré, Lisa Topolnik, Frances K Skinner
Determining how intrinsic cellular properties govern and modulate neuronal input-output processing is a critical endeavor for understanding microcircuit functions in the brain. However, lack of cellular specifics and nonlinear interactions prevent experiments alone from achieving this. Building and using cellular models is essential in these efforts. We focus on uncovering the intrinsic properties of mus musculus hippocampal type 3 interneuron-specific (IS3) cells, a cell type that makes GABAergic synapses onto specific interneuron types, but not pyramidal cells...
July 2016: ENeuro
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