Non-Status Epilepticus female rats show seizure-like behaviors in the chronic phase of Pilocarpine experimental model

Abstract Only few studies have focus on animals that received Pilocarpine (Pilo) and did not develop behavioral status epilepticus (SE) and, whether they may become epileptic in the models chronic phase. Previews works observed mossy fiber sprouting in the hippocampus of Non-SE (NSE) rats, while others observed spontaneous and recurrent seizures (SRS) 6 - 8 months after animals received Pilo. It is known that neuronal excitability is influenced by female hormones, as well as, the occurrence of SE in castrated and non-castrated female rats. However, it is not known whether females that received Pilo and did not show SE, may have SRS. The aim of this work was to investigate whether castrated and non-castrated female rats that did not show behavioral SE after Pilo, will develop SRS in the following one-year. For that, animals received 360 mg/kg of Pilo and were video monitored for 12 months. SE females from castrated and non-castrated groups became epileptic since the first month after drug injection. Epileptic behaviors were identified watching video monitoring recordings in the fast speed. Castrated and Non-castrated NSE animals showed behaviors resembling seizures described by Racine Scale stages 1 - 3. Motor alterations showed by NSE groups could be observed only when recordings were analyzed in slow speed. In addition, behavioral manifestations as, rhythmic head movements, sudden head movements, whole body movements and immobility were also observed in both, SE and NSE groups. We concluded that NSE female rats may have become epileptic. Adding to it, slow speed analysis of motor alterations was essential for the observation of NSE findings, which suggests that possibly many motor alterations have been underestimated in epilepsy experimental research.

Resumo Poucos são os estudos com foco em animais que receberam Pilocarpina (Pilo) e não desenvolveram status epilepticus (SE) comportamental e, se os mesmos se tornarão epilépticos na fase crônica do modelo. Autores observaram o brotamento das fibras musgosas no hipocampo de ratos Não-SE (NSE), enquanto outros observaram crises espontâneas e recorrentes (CER) 6 - 8 meses após receberam a droga. A excitabilidade neuronal é influenciada pelos hormônios femininos e, da mesma forma, a ocorrência de SE em ratas castradas e não-castradas. Entretanto, não é sabido se as fêmeas que não apresentam SE terão CER. O objetivo deste trabalho foi investigar se fêmeas castradas e não castradas que não tiveram SE comportamental após a injeção de Pilo desenvolverão CER dentro de um ano. Para isto, os animais receberam 360 mg/kg de Pilo e foram videomonitorados por 12 meses. As fêmeas SE castradas e não-castradas se tornaram epilépticas desde o primeiro mês pós Pilo. O comportamento epiléptico foi identificado assistindo as gravações na velocidade rápida. As fêmeas NSE castradas e não-castradas apresentaram comportamentos similares aos estágios 1 - 3 da Escala de Racine. As alterações motoras nestes grupos (NSE) foram observadas apenas quando as videomonitoração foi analisada na velocidade lenta. Além destas, manifestações comportamentais como movimentos rítmicos da cabeça, movimentos súbitos da cabeça, movimentos de todo o corpo e imobilidade também foram observadas em ambos grupos, SE e NSE. Concluímos que as fêmeas NE podem ter se tornado epilépticas. Adicionado a isto, a análise das alterações motoras na velocidade lenta foi essencial para a observação dos achados das fêmeas NSE, o que sugere que possivelmente muitas alterações motoras têm sido subestimados na pesquisa em epilepsia experimental.

Non-Status Epilepticus female rats show seizure-like behaviors in the chronic phase of Pilocarpine experimental model / Ratas sem Status Epilepticus apresentam comportamento do tipo crise epiléptica na fase crônica do modelo experimental da Pilocarpina

Abstract Only few studies have focus on animals that received Pilocarpine (Pilo) and did not develop behavioral status epilepticus (SE) and, whether they may become epileptic in the model's chronic phase. Previews works observed mossy fiber sprouting in the hippocampus of Non-SE (NSE) rats, while others observed spontaneous and recurrent seizures (SRS) 6 - 8 months after animals received Pilo. It is known that neuronal excitability is influenced by female hormones, as well as, the occurrence of SE in castrated and non-castrated female rats. However, it is not known whether females that received Pilo and did not show SE, may have SRS. The aim of this work was to investigate whether castrated and non-castrated female rats that did not show behavioral SE after Pilo, will develop SRS in the following one-year. For that, animals received 360 mg/kg of Pilo and were video monitored for 12 months. SE females from castrated and non-castrated groups became epileptic since the first month after drug injection. Epileptic behaviors were identified watching video monitoring recordings in the fast speed. Castrated and Non-castrated NSE animals showed behaviors resembling seizures described by Racine Scale stages 1 - 3. Motor alterations showed by NSE groups could be observed only when recordings were analyzed in slow speed. In addition, behavioral manifestations as, rhythmic head movements, sudden head movements, whole body movements and immobility were also observed in both, SE and NSE groups. We concluded that NSE female rats may have become epileptic. Adding to it, slow speed analysis of motor alterations was essential for the observation of NSE findings, which suggests that possibly many motor alterations have been underestimated in epilepsy experimental research.

Resumo Poucos são os estudos com foco em animais que receberam Pilocarpina (Pilo) e não desenvolveram status epilepticus (SE) comportamental e, se os mesmos se tornarão epilépticos na fase crônica do modelo. Autores observaram o brotamento das fibras musgosas no hipocampo de ratos Não-SE (NSE), enquanto outros observaram crises espontâneas e recorrentes (CER) 6 - 8 meses após receberam a droga. A excitabilidade neuronal é influenciada pelos hormônios femininos e, da mesma forma, a ocorrência de SE em ratas castradas e não-castradas. Entretanto, não é sabido se as fêmeas que não apresentam SE terão CER. O objetivo deste trabalho foi investigar se fêmeas castradas e não castradas que não tiveram SE comportamental após a injeção de Pilo desenvolverão CER dentro de um ano. Para isto, os animais receberam 360 mg/kg de Pilo e foram videomonitorados por 12 meses. As fêmeas SE castradas e não-castradas se tornaram epilépticas desde o primeiro mês pós Pilo. O comportamento epiléptico foi identificado assistindo as gravações na velocidade rápida. As fêmeas NSE castradas e não-castradas apresentaram comportamentos similares aos estágios 1 - 3 da Escala de Racine. As alterações motoras nestes grupos (NSE) foram observadas apenas quando as videomonitoração foi analisada na velocidade lenta. Além destas, manifestações comportamentais como movimentos rítmicos da cabeça, movimentos súbitos da cabeça, movimentos de todo o corpo e imobilidade também foram observadas em ambos grupos, SE e NSE. Concluímos que as fêmeas NE podem ter se tornado epilépticas. Adicionado a isto, a análise das alterações motoras na velocidade lenta foi essencial para a observação dos achados das fêmeas NSE, o que sugere que possivelmente muitas alterações motoras têm sido subestimados na pesquisa em epilepsia experimental.

Optical fiber thermo-refractometer.

This work presents the implementation of a thermo-refractometer, which integrates the measurement of both refractive index and temperature in a single optical fiber structure. To this purpose, a lossy mode resonance (LMR)-based refractometer is obtained by means of the deposition of a titanium dioxide (TiO2) thin film onto a side-polished (D-shaped) single mode fiber. Measurement and subsequent temperature compensation are achieved by means of a fiber Bragg grating (FBG) inscribed in the core of the D-shaped region. The LMR wavelength shift is monitored in transmission while the FBG (FBG peak at 1533 nm) displacement is observed in reflection. The LMR is sensitive to both the surrounding refractive index (SRI), with a sensitivity of 3725.2 nm/RIU in the 1.3324-1.3479 range, and the temperature (- 0.186 nm/°C); while the FBG is only affected by the temperature (32.6 pm/°C in the 25°C - 45°C range). With these values, it is possible to recover the SRI and temperature variations from the wavelength shifts of the LMR and the FBG, constituting a thermo-refractometer, where it is suppressed the effect of the temperature over the refractometer operation, which could cause errors in the fourth or even third decimal of the measured SRI value.

Non-Status Epilepticus female rats show seizure-like behaviors in the chronic phase of Pilocarpine experimental model.

Only few studies have focus on animals that received Pilocarpine (Pilo) and did not develop behavioral status epilepticus (SE) and, whether they may become epileptic in the model's chronic phase. Previews works observed mossy fiber sprouting in the hippocampus of Non-SE (NSE) rats, while others observed spontaneous and recurrent seizures (SRS) 6 - 8 months after animals received Pilo. It is known that neuronal excitability is influenced by female hormones, as well as, the occurrence of SE in castrated and non-castrated female rats. However, it is not known whether females that received Pilo and did not show SE, may have SRS. The aim of this work was to investigate whether castrated and non-castrated female rats that did not show behavioral SE after Pilo, will develop SRS in the following one-year. For that, animals received 360 mg/kg of Pilo and were video monitored for 12 months. SE females from castrated and non-castrated groups became epileptic since the first month after drug injection. Epileptic behaviors were identified watching video monitoring recordings in the fast speed. Castrated and Non-castrated NSE animals showed behaviors resembling seizures described by Racine Scale stages 1 - 3. Motor alterations showed by NSE groups could be observed only when recordings were analyzed in slow speed. In addition, behavioral manifestations as, rhythmic head movements, sudden head movements, whole body movements and immobility were also observed in both, SE and NSE groups. We concluded that NSE female rats may have become epileptic. Adding to it, slow speed analysis of motor alterations was essential for the observation of NSE findings, which suggests that possibly many motor alterations have been underestimated in epilepsy experimental research.

On the generation of internal waves by river plumes in subcritical initial conditions.

Internal waves (IWs) in the ocean span across a wide range of time and spatial scales and are now acknowledged as important sources of turbulence and mixing, with the largest observations having 200 m in amplitude and vertical velocities close to 0.5 m s-1. Their origin is mostly tidal, but an increasing number of non-tidal generation mechanisms have also been observed. For instance, river plumes provide horizontally propagating density fronts, which were observed to generate IWs when transitioning from supercritical to subcritical flow. In this study, satellite imagery and autonomous underwater measurements are combined with numerical modeling to investigate IW generation from an initial subcritical density front originating at the Douro River plume (western Iberian coast). These unprecedented results may have important implications in near-shore dynamics since that suggest that rivers of moderate flow may play an important role in IW generation between fresh riverine and coastal waters.

Long lived second mode internal solitary waves in the Andaman Sea.

Internal waves are density oscillations propagating along the ocean's inner stratification, which are now acknowledged as a key constituent of the ocean's dynamics. They usually result from barotropic tides, which flow over bottom topography, causing density oscillations to propagate along the pycnocline with a tidal frequency (i.e. internal tides). These large-scale waves propagate away from their forcing bathymetry and frequently disintegrate into nonlinear short-scale (higher-frequency) internal wave packets. Typically, short-scale internal wave observations in the ocean are associated with vertical structures (in the water column) of the lowest fundamental mode. Higher vertical modes have recently been documented as well, but these are commonly short-lived (up to a few hours). However, unprecedented satellite images showing long-lived short-scale mode-2 internal waves have now been documented in the Andaman Sea, and we report here the companion results of a non-hydrostatic and fully nonlinear numerical model. The simulations reproduce the waves' main characteristics as observed in satellite imagery, and the results suggest a resonant coupling with a larger-scale mode-4 internal tide as an explanation for their long-lived character.

Three-Dimensional Correlative Imaging of a Malaria-Infected Cell with a Hard X-ray Nanoprobe.

Benefiting from the recent advances of synchrotron X-ray nanoprobes, we demonstrate three-dimensional (3D) correlative nanoimaging on malaria-infected human red blood cells. By combining X-ray fluorescence tomography and phase contrast nanotomography on the same cell with sub-100 nm pixel size, we establish a routine workflow from the data acquisition, data processing, to tomographic reconstruction. We quantitatively compare the elemental volumes obtained with different reconstruction methods, with the total variation minimization giving the most satisfactory results. We reveal elemental correlations in different cell compartments more reliably on reconstructions as opposed to 2D projections. Finally, we determine for the first time the 3D mass fraction maps of multiple elements at the subcellular level. The estimated total number of Fe atoms and the total mass of red blood cells show very good agreement with previously reported values.

Quantitative region-of-interest tomography using variable field of view.

In X-ray computed tomography, the task of imaging only a local region of interest (ROI) inside a larger sample is very important. However, without a priori information, this ROI cannot be exactly reconstructed using only the image data limited to the ROI. We propose here an approach of region-of-interest tomography, which reconstructs a ROI within an object from projections of different fields of view acquired on a specific angular sampling scheme in the same tomographic experiment. We present a stable procedure that not only yields high-quality images of the ROI but keeps as well the quantitative contrast on the reconstructed images. In addition, we analyze the minimum number of projections required for ROI tomography from the point of view of the band region of the Radon transform, which confirms this number must be estimated based on the size of the entire object and not only on the size of the ROI.

A three-dimensional view of structural changes caused by deactivation of fluid catalytic cracking catalysts.

Since its commercial introduction three-quarters of a century ago, fluid catalytic cracking has been one of the most important conversion processes in the petroleum industry. In this process, porous composites composed of zeolite and clay crack the heavy fractions in crude oil into transportation fuel and petrochemical feedstocks. Yet, over time the catalytic activity of these composite particles decreases. Here, we report on ptychographic tomography, diffraction, and fluorescence tomography, as well as electron microscopy measurements, which elucidate the structural changes that lead to catalyst deactivation. In combination, these measurements reveal zeolite amorphization and distinct structural changes on the particle exterior as the driving forces behind catalyst deactivation. Amorphization of zeolites, in particular, close to the particle exterior, results in a reduction of catalytic capacity. A concretion of the outermost particle layer into a dense amorphous silica-alumina shell further reduces the mass transport to the active sites within the composite.Catalyst deactivation in fluid catalytic cracking processes is unavoidably associated with structural changes. Here, the authors visualize the deactivation of zeolite catalysts by ptychography and other imaging techniques, showing pronounced amorphization of the outer layer of the catalyst particles.

Theoretical modulation of singlet/triplet chemiexcitation of chemiluminescent imidazopyrazinone dioxetanone via C8-substitution.

Coelenterazine, a member of the imidazopyrazinone class of chemiluminescent substrates, presents significant potential as a dynamic probe of reactive oxygen species in a biological environment, such as a superoxide anion, in which these species are important in cellular biology and pathology. The objective of the current study was to understand in what way the efficiency of singlet and triplet chemiexcitation could be modulated, towards a more efficient use of imidazopyrazinone-based compounds as dynamic chemiluminescent probes. To this end the thermolysis of imidazopyrazinone dioxetanone, substituted at the C8-position with electron-donating or electron-withdrawing groups, was characterized with a theoretical approach based on density functional theory. Substituents with different electron-donating/withdrawing characters have only a limited effect on the singlet chemiexcitation of anionic dioxetanone. For neutral dioxetanone, both electron-withdrawing and weak electron-donating substituents increase singlet chemiexcitation, to the contrary of strong electron-donating groups. During their thermolysis reaction, all molecules presented regions of degeneracy with triplet states, thereby indicating the possibility of triplet chemiexcitation.

Characterization of cellulose membranes modified with luminescent silicon quantum dots nanoparticles.

A highly hydrophilic planar membrane fabricated with regenerated cellulose (RC-4 membrane), a biocompatible polymer, was modified by inclusion of water-soluble silicon quantum dot nanoparticles (SiQDs). Both bare SiQDs and SiQDs coated with a PAMAM-OH dendrimer were employed in order to obtain luminescent and thermally stable membrane systems (RC-4/SiQDs and RC-4/SiQDs-PAMAM-OH membranes). Original and SiQDs-modified membranes were characterized by fluorescence spectroscopy (steady and confocal), derivative thermogravimetric analysis and impedance spectroscopy measurements. According to these results, both SiQDs-regenerated cellulose composite membranes present luminescent character as well as higher thermal resistance and conductivity than the original sample, although the dendrimer coverage of the SiQDs might partially shield such effects. Moreover, the permanence of SiQDs nanoparticles in the structure of the cellulosic support in aqueous environments and their effect on diffusive transport were determined by water uptake as well as by membrane potential measurements at different concentrations of a model electrolyte (KCl). These results demonstrate the possible use of these stable nano-engineered membranes, which are based on SiQDs nanoparticles, in electrochemical devices under flow conditions.

Fluorescent sensor for Cr(VI) based in functionalized silicon quantum dots with dendrimers.

Highly luminescent nanoparticles based in Silicon quantum dots, coated by hydroxyl PAMAM dendrimer (PAMAM-OH) of 5th generation, were obtained by one step process by hydrothermal treatment of 3-Aminopropyl)triethoxysilane (APTES) in aqueous solution. Previous to the optimization of the synthesis procedure, different dendritic molecules of 5th generation were tested to obtain the most intense fluorescence signal. The influence of different parameters such ratio APTES/PAMAM-OH, pH and ionic strength on the fluorescence intensity was studied. The fluorescence spectra showed maximum excitation and emission wavelengths at 370 and 446 nm, respectively. The obtained silicon nanoparticles (SiQDs@PAMAM-OH) were characterized by TEM, DLS and XPS, and were found to detect selectively Cr(VI) in aqueous solutions at 2.7 µM level of detection, sensitivity of 0.2 µM with a RSD of 0.16% (n=10). To study the feasibility of the proposed system for Cr(VI) detection, it was tested in real electrochemical solution bath and a tanning effluent obtained from electrochemical industry and with two certified waters, demonstrating promising outcomes as nano-sensor.

Fluorescent chemosensor for pyridine based on N-doped carbon dots.

Fluorescent carbon dots (CDs) and its nitrogen doped (N-CDs) nanoparticles have been synthesized from lactose as precursor using a bottom-up hydrothermal methodology. The synthesized nanoparticles have been characterized by elemental analysis, FTIR, Raman, TEM, DLS, XPS, and steady-state and life-time fluorescence. The synthesized carbon nanoparticles, CDs and N-CDs, have a size at about 7.7±2.4 and 50±15nm, respectively, and quantum yields of 8% (CDs) and 11% (N-CDs). These techniques demonstrated the effectiveness of the synthesis procedure and the functionalization of the CDs surface with amine and amide groups in the presence of NH3 in aqueous media. The effect of excitation wavelength and pH on the luminescent properties was studied. Under the optimal conditions, the nitrogen doped nanoparticles can be used as pyridine sensor in aqueous media because they show an enhancement of its fluorescence with a good linear relationship. The analytical method is simple, reproducible and very sensitive for pyridine determination.

Effects of CO2 on Acer negundo pollen fertility, protein content, allergenic properties, and carbohydrates.

Atmospheric gaseous pollutants can induce qualitative and quantitative changes in airborne pollen characteristics. In this work, it was investigated the effects of carbon dioxide (CO2) on Acer negundo pollen fertility, protein content, allergenic properties, and carbohydrates. Pollen was collected directly from the anthers and in vitro exposed to three CO2 levels (500, 1000, and 3000 ppm) for 6 and 24 h in an environmental chamber. Pollen fertility was determined using viability and germination assays, total soluble protein was determined with Coomassie Protein Assay Reagent, and the antigenic and allergenic properties were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunological techniques using patients' sera. Also, pollen fructose, sucrose, and glucose values were determined. Carbon dioxide exposure affected negatively pollen fertility, total soluble protein content, and fructose content. The patient sera revealed increased IgE reactivity to proteins of A. negundo pollen exposed to increasing levels of the pollutant. No changes were detected in the SDS-PAGE protein profiles and in sucrose and glucose levels. Our results indicate that increase in atmospheric CO2 concentrations can have a negative influence of some features of A. negundo airborne pollen that can influence the reproductive processes as well as respiratory pollen allergies in the future.

Microwave-assisted synthesis of carbon dots and its potential as analysis of four heterocyclic aromatic amines.

Fluorescent water soluble carbon nanoparticles, in short carbon dots (CDs), was synthesized from lactose by microwave assisted hydrochloric acid method. Characterized by TEM and DLS to obtain the morphology shape (average 10nm in size), with a higher negative surface charge supported by the composition was obtained by XPS spectroscopy. The maximum of the emission was centered at 450 nm with a lifetime of 2.1 ns. Without further functionalization of the CDs a nanosensor was obtained that responded exponentially to HAAs in the 0.35-0.45 mg L(-1) concentration range by fluorescence static quenching, demonstrated by the lifetime analysis of the CDs in presence of HAAs. Some amino compounds were selected as model for interferences to evaluate the selectivity of this method, showing a notorious added value, with recoveries around 98%. The accuracy of the method was in terms of RSD about 2.5%. The results suggest their promising applications in chemical sensing.

Carbon dots obtained using hydrothermal treatment of formaldehyde. Cell imaging in vitro.

Highly photoluminescent carbon dots have been prepared in a one step procedure by hydrothermal treatment of formaldehyde at 180 °C. They show green fluorescence under UV light exposure and emission spectra are centered at 440 nm. Fluorescence lifetimes comprise between 0.7 and 2.70 ns, when the synthesis process lasted for 1-7 days. TEM images of nanoparticles showed a homogeneous size/shape distribution. When the thermal treatment process was carried out for a long time (30 days) formation of aggregates occurred. Carbon dots were further analyzed using (1)H and (13)C-NMR, Raman and FTIR spectroscopy techniques and XPS. Cell imaging of nanoparticles was carried out by using mouse MC3T3-E1 pre-osteoblasts as a model. The nanoparticles were selectively localized in the cytoplasm without further functionalization and could be realized by cellular phagocytosis, so that the fluorescence of these can be used for live cell imaging in vitro.

Quantitative analysis of organophosphorus pesticides in freshwater using an optimized firefly luciferase-based coupled bioluminescent assay.

In this paper, a coupled bioluminescent assay, relying on the coupling of the enzymes acetylcholinesterase, S-acetyl-coenzyme A synthetase and firefly luciferase, for the detection and quantitation of organophosphorus pesticides, is presented. Using malathion as a model organophosphorus pesticide, the assay was optimized through statistical experimental design methodology, namely Plackett-Burman and central composite designs. The optimized method requires only 20 µL of sample. The linear range for the assay was 2.5-15 µM of malathion, with limits of detection and quantitation of 1.5 and 5.0 µM, respectively. This simple, fast and robust method allows samples to be analyzed at room temperature and without any pretreatment.