Membrane interactions of S100A12 (Calgranulin C)

S100A12 (Calgranulin C) is a small acidic calcium-binding peripheral membrane protein with two EF-hand structural motifs. It is expressed in macrophages and lymphocytes and highly up-regulated in several human inflammatory diseases. In pigs, S100A12 is abundant in the cytosol of granulocytes, where it is believed to be involved in signal modulation of inflammatory process. In this study, we investigated the interaction of the porcine S100A12 with phospholipid bilayers and the effect that ions (Ca2+, Zn2+ or both together) have in modifying protein-lipid interactions. More specifically, we intended to address issues such as: (1) is the protein-membrane interaction modulated by the presence of ions? (2) is the protein overall structure affected by the presence of the ions and membrane models simultaneously? (3) what are the specific conformational changes taking place when ions and membranes are both present? (4) does the protein have any kind of molecular preferences for a specific lipid component? To provide insight into membrane interactions and answer those questions, synchrotron radiation circular dichroism spectroscopy, fluorescence spectroscopy, and surface plasmon resonance were used. The use of these combined techniques demonstrated that this protein was capable of interacting both with lipids and with ions in solution, and enabled examination of changes that occur at different levels of structure organization. The presence of both Ca2+ and Zn2+ ions modify the binding, conformation and thermal stability of the protein in the presence of lipids. Hence, these studies examining molecular interactions of porcine S100A12 in solution complement the previously determined crystal structure information on this family of proteins, enhancing our understanding of its dynamics of interaction with membranes

Generation and propagation of epileptiform activity in the hippocampal slice preparation

For the investigation of epileptiform events in the hippo-campal CA1 field, in-vitro slices of the guinea-pig were used. After adding 0.1 mmol 4-aminopyridine to the bathing medium, field potentials were recorded with an electrode array, consisting of 8 semi-microelectrodes at spacings of 0.1 ram. A comparison was made between the spontaneously occurring field potentials (SFP) in CA I and those evoked by different inputs to the CA1 pyramidal cells, namely alveus, str. oriens and Schaffer collaterals. For this purpose the electrode array was placed in CA l, parallel to the axes for the pyramidal cells. The regularly occurring SEP's presented a similar distribution as the potentials evoked by stimulation of str. oriens or alveus of CAI, but differed from those evoked by stimulation of the chaffer colaterals. This indicates that in CA1 SFP's are generated in a similar way as field potentials evoked by alveus or str. oriens stimulation. It was also found that SFP's are propagated from CA3 and CAI at a velocity of 0.16-0.30 m/sec. Therefore pathways in alveus and str. oriens, connecting CA3 and CA1, may be important in propagating epileptiform activity. This was supported by experiments in which different pathways were sectioned

The Vortex-Wave equation with a single vortex as the limit of the Euler equation

In this article we consider the physical justification of the Vortex-Wave equation introduced by Marchioro and Pulvirenti in the case of a single point vortex moving in an ambient vorticity. We consider a sequence of solutions for the Euler equation in the plane corresponding to initial data consisting of an ambient vorticity in $L^1\cap L^\infty$ and a sequence of concentrated blobs which approach the Dirac distribution. We introduce a notion of a weak solution of the Vortex-Wave equation in terms of velocity (or primitive variables) and then show, for a subsequence of the blobs, the solutions of the Euler equation converge in velocity to a weak solution of the Vortex-Wave equation.Comment: 24 pages, to appea

Determinant factors of long-term performance development in young swimmers

To develop a performance predictor model based on swimmers’ biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction. 91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors. Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] –2.05, P < .001), arm span (EST –0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST –0.17, P = .001) were entered in the final model. Over 3 consecutive seasons young swimmers’ performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.info:eu-repo/semantics/publishedVersio

Physical growth of schoolchildren from the Jequitinhonha Valley, Minas Gerais, Brazil: Comparison with the CDC-2000 reference using the LMS method

Objective: To analyse the physical growth of a representative school population sample from the Jequitinhonha Valley, Minas Gerais, Brazil, in comparison with the reference proposed by the Centre for Disease Control and Prevention (CDC-2000). Methods: The sample was composed of 5100 individuals (2730 girls and 2370 boys), aged 6-18 years. Body weight-for-age and height-for-age percentiles were obtained using the LMS method. Statistical and graphical comparisons were made with the corresponding percentiles of the CDC-2000 reference, estimated using the same method. Results: Overall, the calculated values of the L (asymmetry) and the S (variability) parameters were quite similar to the CDC-2000 reference values. However, M(median) was substantially different from the reference used in the study, mainly in schoolchildren over 12-13 years of age of both genders. The magnitude of the deficits of height-for-age and body weight-for-age observed in the schoolchildren from the Jequitinhonha Valley, Minas Gerais, Brazil, varied from 4 to 6 cm and from 3 to 6 kg, respectively. Conclusion: The body weight-for-age and height-for-age percentiles of schoolchildren population in the Jequitinhonha Valley, Minas Gerais, Brazil differed substantially from those referenced

Smartpaddle® as a new tool for monitoring swimmers’ kinematic and kinetic variables in real time

Smart technology, such as wearables, applied to sports analysis is essential for performance enhancement. New technological equipment can promote the interaction between researchers, coaches, and athletes, facilitating information exchange in real time. Objective: The aim of this study was to present new wearable equipment (SmartPaddle®) to measure kinematic and kinetic variables in swimming and understand the agreement of the propulsive force variable with a pressure sensor system. Methods: Four male university swimmers (18.75±0.50 years old, 71.55±6.80 kg of body mass, and 175.00±5.94 cm of height) were analyzed. The SmartPaddle® and a pressure sensor system were used to collect the kinetic data (propulsive force). The comparison between the propulsive force methods was based on t-test paired samples, simple linear regression, and Bland-Altman plots. Results: SmartPaddle® is a system that consists of (i) a wearable device, (ii) the Trainesense Session Manager mobile application for recording, and; (iii) the Analysis Center for analysis and data storage. It records a set of kinematic and kinetic parameters useful for coaches daily. The comparison between the different methods revealed non-significant differences and a very-high relationship. Conclusion: SmartPaddle® is a feasible wearable device that swimmersswimmers can use can use to provide immediate data about their kinematic and kinetic profile. Coaches can easily monitor these parameters and give immediate suggestions to their swimmers on a daily basis.This work is supported by national funds (FCT - Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio