Comparative analysis of the use of natural and synthetic antioxidants in chicken meat: an update review.

The search for healthy foods has attracted the industry's attention to developing products that use natural ingredients, including natural antioxidants. Antioxidants act as free radicals or oxygen scavengers, inhibiting lipid oxidation and adversely affecting meat products' sensory and nutritional quality. Several synthetic antioxidants have been used in the meat industry; however, studies point to health risks related to their consumption. Such fact drives research into natural antioxidants extracted from grains, oilseeds, spices, fruits, and vegetables, which may have a health-promoting effect. This manuscript evaluates the effectiveness of several natural antioxidants in improving the quality and shelf life of chicken meat products during processing, storage, and distribution. The potential effects of natural antioxidants widely used in chicken products are also discussed. It can be concluded that these natural antioxidants are possible substitutes for synthetic ones. However, their use can affect the product's characteristics.

Validation of electrodeposited 241Am alpha-particle sources for use in liquified gas detectors at cryogenic temperatures.

This paper describes a procedure for the validation of alpha-particle sources (exempt unsealed sources) to be used in experimental setups with liquefied gases at cryogenic temperatures (down to -196 °C) and high vacuum. These setups are of interest for the development and characterization of neutrino and dark matter detectors based on liquid argon, among others. Due to the high purity requirements, the sources have to withstand high vacuum and cryogenic temperatures for extended periods. The validation procedure has been applied to 241Am sources produced by electrodeposition.

P2X7 receptor antagonist improves gastrointestinal disorders in spontaneously hypertensive rats.

The purinergic system participates in the control of blood pressure. Hypertension promotes the occurrence of gastrointestinal disorders such as intestinal inflammation and gastric emptying delay. This study aimed i) to investigate the participation of the P2X7 receptor blocker Brilliant Blue G (BBG) on gastric emptying of solids and changes in oxidative stress in the gastric fundus, duodenum, and colon of spontaneously hypertensive rats (SHR) and ii) to study the putative relationship of this effect with the renin-angiotensin system. Rats were divided into five groups: Control, SHR, SHR+BBG, SHR+BBG+ATP, and SHR+BBG+ANG II. In the gastrointestinal tract, we assessed gastric emptying (GE) and oxidative stress markers (NOx, MPO, GSH, SOD). We observed a decrease in the GE rate (P<0.05) in SHR vs control rats (21.8±2.0% vs 42.8±3.5%). The decrease in GE was returned (P<0.05) to control levels by BBG in SHR rats (21.8±2.0% vs 41.6±3.2%). Co-administration of ATP or ANG II together with BBG bypassed the effect of the P2X7 antagonist on GE in SHR (P<0.05) (21.9±5.0% vs 25.6±3.0% vs 41.6±3.2%). The MPO activity increased (P<0.05) in the gastric fundus of SHR compared to control rats (6.12±2.26 vs 0.077±0.02 UMPO/mg tissue); this effect was prevented (P<0.05) by BBG (0.55±0.15 vs 6.12±2.26 UMPO/mg tissue). Data demonstrated that blockage of P2X7 receptors with BBG can improve the GE delay and oxidative stress biomarkers in SHR animals. This preventive effect of BBG on GE delay was abrogated by ANG II and ATP, thus prompting crosstalk between renin-angiotensin and the purinergic signaling systems underlying this phenomenon.

P2X7 receptor antagonist improves gastrointestinal disorders in spontaneously hypertensive rats

The purinergic system participates in the control of blood pressure. Hypertension promotes the occurrence of gastrointestinal disorders such as intestinal inflammation and gastric emptying delay. This study aimed i) to investigate the participation of the P2X7 receptor blocker Brilliant Blue G (BBG) on gastric emptying of solids and changes in oxidative stress in the gastric fundus, duodenum, and colon of spontaneously hypertensive rats (SHR) and ii) to study the putative relationship of this effect with the renin-angiotensin system. Rats were divided into five groups: Control, SHR, SHR+BBG, SHR+BBG+ATP, and SHR+BBG+ANG II. In the gastrointestinal tract, we assessed gastric emptying (GE) and oxidative stress markers (NOx, MPO, GSH, SOD). We observed a decrease in the GE rate (P<0.05) in SHR vs control rats (21.8±2.0% vs 42.8±3.5%). The decrease in GE was returned (P<0.05) to control levels by BBG in SHR rats (21.8±2.0% vs 41.6±3.2%). Co-administration of ATP or ANG II together with BBG bypassed the effect of the P2X7 antagonist on GE in SHR (P<0.05) (21.9±5.0% vs 25.6±3.0% vs 41.6±3.2%). The MPO activity increased (P<0.05) in the gastric fundus of SHR compared to control rats (6.12±2.26 vs 0.077±0.02 UMPO/mg tissue); this effect was prevented (P<0.05) by BBG (0.55±0.15 vs 6.12±2.26 UMPO/mg tissue). Data demonstrated that blockage of P2X7 receptors with BBG can improve the GE delay and oxidative stress biomarkers in SHR animals. This preventive effect of BBG on GE delay was abrogated by ANG II and ATP, thus prompting crosstalk between renin-angiotensin and the purinergic signaling systems underlying this phenomenon.

Factors associated with low back pain in air force fighter pilots: a cross-sectional study.

INTRODUCTION: Low back pain in military pilots is a frequent condition which constantly leads to absences from work, decreased concentration and performance during flight, as well as changes in work functions. METHODS: This is a cross-sectional analytical study including 28 fighter pilots who underwent an evaluation comprising muscle strength and fatigue resistance, trunk mobility and application of questionnaires to identify associated clinical factors. RESULTS: It was observed that 68% of the pilots reported low back pain with an average pain intensity of 3.7 at numerical pain scale in the last week. No significant differences were observed regarding the range of motion and trunk muscle strength when pilots with low back pain were compared with asymptomatic pilots. However, lateral right trunk muscle (mean difference=16, 95% CI 0.6 to 33.0]) and lateral left trunk muscle (mean difference=22, 95% CI 1 to 44) fatigue sooner in pilots with low back pain when the two groups were compared (p=0.04 for both). CONCLUSION: There was a high rate of low back pain complaints among fighter pilots. There was also a significant reduction in fatigue resistance of the lateral trunk muscles in symptomatic pilots when compared with asymptomatic pilots. These factors must be considered in the physical training of this population.

Association between race/color and incidence of hypertension in the ELSA-Brasil population: investigating the mediation of racial discrimination and socioeconomic position.

OBJECTIVE: To investigate the mediation effect of socioeconomic position and racial discrimination in the association between race/color and incidence of hypertension in 4-years follow up. METHODS: We included 8,370 participants of the Longitudinal Study of Adult Health (ELSA-Brasil). A latent variable was constructed to represent socioeconomic position (SEP). The perception of discrimination was measured through an adaptation of the Lifetime Major Events Scale; and hypertension was defined using standard criteria. We investigated Body Mass Index (BMI) due to its role in proximal risk for hypertension. To investigate the mediating role of SEP and racial discrimination, we used structural equation modeling. RESULTS: SEP had a direct and negative effect on HT incidence (HT incidence increased in worse SEP categories), while the effect of BMI on HT was direct and positive. We did not find significant direct effects of race/color and racial discrimination on HT. As for indirect effects, we observed associations between race/color and HT only through SEP mediation. CONCLUSION: According to our results, race/color is indirectly related to HT incidence, mediated by SEP. Racial discrimination was not a mediator in the relationship between race/color and HT in the follow-up period.

A comprehensive review of powering methods used in state-of-the-art miniaturized implantable electronic devices.

Microfabrication techniques that allow the integration of all the components in compact and effective volumes, along with the developments observed in sensor and actuator miniaturization, optimization of microelectronic circuits and, ultimately, wireless communication capabilities, have provided the tools required to develop implants for applications so far technically impossible. However, the scaling down of implantable devices raises the problem of how to power them, since batteries have not scaled down as much as the implants. Consequently, energy sources for implantable electronic devices that do not rely on, or at least mitigate, the requirement for a battery are emerging at an astonishing pace. This paper presents a comprehensive review of recent implantable bioelectronic devices that employ alternative powering methods such as energy harvesting and wireless power transfer. A comparison between the different powering methods is provided, along with a discussion of how these may be suited for the device of the future.

Heterotrophic flagellates (Amorpha and Diaphoretiches) in phytotelmata bromeliad (Bromeliaceae) / Flagelados heterotróficos (Amorpha e Diaphoretiches) em fitotelmata de bromélia (Bromeliaceae)

Abstract Many plants may accumulate rainwater, forming phytotelmata, aquatic microhabitats inhabited by various organisms. The aim of this study was to conduct an inventory of heterotrophic flagellates associated with phytotelmata of the bromeliad Aechmea distichantha Lem., found in rocky cliffs on the Upper Paraná River. The bromeliads were removed manually from the rocky wall, the water was removed and cultures of organisms of each plant were mounted in Petri dishes. Sixteen species of heterotrophic flagellate were recorded, drawn and described, among them one species belonging to the Amorpha Domain and 15 species to the Diaphoretiches Domain. The groups with most species were Euglenida and Kinetoplastea. The low diversity of heterotrophic flagellates recorded in this study, compared to the plankton of lakes and reservoirs, is probably related to the fact that phytotelmata are habitats with extreme environmental conditions, thus selecting organisms tolerant to these environments.

Resumo Em sua superfície externa, muitas plantas podem acumular água da chuva formando fitotelmata, ou seja, micro-habitat aquáticos colonizados por diversos organismos, entre eles, os flagelados protistas. Fez-se um inventário de flagelados heterotróficos associados ao fitotelmata da bromélia Aechmea distichantha Lem., encontrada em paredões rochosos em um trecho da bacia do alto rio Paraná. As bromélias foram retiradas manualmente de paredão rochoso e, em laboratório, a água foi retirada dos tanques de cada planta, e foram montadas culturas dos organismos em placas de Petri. Os flagelados heterotróficos foram, então, observados in vivo sob microscópio óptico Olympus BX51, com sistema de contraste de interferência diferencial (DIC) acoplado. Dezesseis espécies flagelados heterotróficos foram registradas, desenhadas e descritas, sendo uma espécie pertencente ao Domínio Amorpha e 15 espécies ao Domínio Diaphoretiches. Os grupos mais especiosos foram Euglenida e Kinetoplastea. A diversidade relativamente reduzida de flagelados heterotróficos, quando comparada ao plâncton de lagos e reservatórios, pode estar relacionada ao fato de os fitotelmata serem habitats limitados, com condições ambientais extremas, selecionando, assim, organismos tolerantes a esses ambientes.

Cáncer de próstata, nuevas opciones de tratamiento: inmunoterapia / Prostate cancer, new treatment advances - immunotherapy

El cáncer de próstata (CaP) es el cuarto cáncer más común en el mundo, y el tratamiento se basa actualmente en la extirpación quirúrgica y/o la radioterapia y/o la terapia hormonal. En los últimos años la inmunoterapia se ha convertido en una importante opción para el tratamiento del cáncer, y aunque los principios de la inmunoterapia evolucionaron durante varios años, la Food and Drug Administration (FDA) estadounidense solo aprobó el sipuleucel-T, lo que condujo a estudios adicionales con otros agentes, comenzando una nueva era en inmuno-oncología. Se están investigando varias vacunas, así como inhibidores de puntos de control. A pesar del entusiasmo actual, es poco probable que cualquiera de los inmunoterapéuticos por sí solo pueda cambiar drásticamente los resultados del CaP, pero las estrategias combinadas son más prometedoras y proporcionan una razón para el optimismo. El objetivo de la inmunoterapia con CaP no tiene que ser la erradicación completa de la enfermedad avanzada, sino más bien el retorno a un equilibrio inmunológico con un estado de enfermedad indolente. Con esfuerzos tan concertados, el futuro de la inmunoterapia en CaP parece más brillante que nunca, y los resultados de muchos ensayos clínicos se publicarán pronto

Prostate cancer (PCa) is the fourth most common cancer in the world and treatment is currently based on surgical removal and/or radiotherapy and/or hormone therapy. In the last few years’ immunotherapy has become an important cancer treatment option. While the principles of immunotherapy evolved, only sipuleucel-T was approved by the Food and Drug Administration (FDA) which lead to further studies with other agents, starting a new era in immuno-oncology. A number of vaccines are under clinical investigation as well as checkpoint inhibitors. Despite the current enthusiasm, it is unlikely that any of the approaches alone can dramatically change PCa outcomes, but strategies combination is more promising and provide a reason for optimism. The goal of immunotherapy in PCa does not have to be the complete eradication of advanced disease, but rather the return to an immunologic equilibrium with an indolent disease state. With such concerted efforts, the future of immunotherapy in PCa looks brighter than ever, with many clinical trial results being published son

Prostate cancer, new treatment advances - immunotherapy. / Cáncer de próstata, nuevas opciones de tratamiento: inmunoterapia.

Prostate cancer (PCa) is the fourth most common cancer in the world and treatment is currently based on surgical removal and/or radiotherapy and/or hormone therapy. In the last few years' immunotherapy has become an important cancer treatment option. While the principles of immunotherapy evolved, only sipuleucel-T was approved by the Food and Drug Administration (FDA) which lead to further studies with other agents, starting a new era in immuno-oncology. A number of vaccines are under clinical investigation as well as checkpoint inhibitors. Despite the current enthusiasm, it is unlikely that any of the approaches alone can dramatically change PCa outcomes, but strategies combination is more promising and provide a reason for optimism. The goal of immunotherapy in PCa does not have to be the complete eradication of advanced disease, but rather the return to an immunologic equilibrium with an indolent disease state. With such concerted efforts, the future of immunotherapy in PCa looks brighter than ever, with many clinical trial results being published soon.

Heterotrophic flagellates (Amorpha and Diaphoretiches) in phytotelmata bromeliad (Bromeliaceae).

Many plants may accumulate rainwater, forming phytotelmata, aquatic microhabitats inhabited by various organisms. The aim of this study was to conduct an inventory of heterotrophic flagellates associated with phytotelmata of the bromeliad Aechmea distichantha Lem., found in rocky cliffs on the Upper Paraná River. The bromeliads were removed manually from the rocky wall, the water was removed and cultures of organisms of each plant were mounted in Petri dishes. Sixteen species of heterotrophic flagellate were recorded, drawn and described, among them one species belonging to the Amorpha Domain and 15 species to the Diaphoretiches Domain. The groups with most species were Euglenida and Kinetoplastea. The low diversity of heterotrophic flagellates recorded in this study, compared to the plankton of lakes and reservoirs, is probably related to the fact that phytotelmata are habitats with extreme environmental conditions, thus selecting organisms tolerant to these environments.

Fabrication and characterization of polyimide-based 'smooth' titanium nitride microelectrode arrays for neural stimulation and recording.

OBJECTIVE: As electrodes are required to interact with sub-millimeter neural structures, innovative microfabrication processes are required to enable fabrication of microdevices involved in such stimulation and/or recording. This requires the development of highly integrated and miniaturized systems, comprising die-integration-compatible technology and flexible microelectrodes. To elicit selective stimulation and recordings of sub-neural structures, such microfabrication process flow can beneficiate from the integration of titanium nitride (TiN) microelectrodes onto a polyimide substrate. Finally, assembling onto cuffs is required, as well as electrode characterization. APPROACH: Flexible TiN microelectrode array integration and miniaturization was achieved through microfabrication technology based on microelectromechanical systems (MEMS) and complementary metal-oxide semiconductor processing techniques and materials. They are highly reproducible processes, granting extreme control over the feature size and shape, as well as enabling the integration of on-chip electronics. This design is intended to enhance the integration of future electronic modules, with high gains on device miniaturization. MAIN RESULTS: (a) Fabrication of two electrode designs, (1) 2 mm long array with 14 TiN square-shaped microelectrodes (80 × 80 µm2), and (2) an electrode array with 2 mm × 80 µm contacts. The average impedances at 1 kHz were 59 and 5.5 kΩ, respectively, for the smaller and larger contacts. Both designs were patterned on a flexible substrate and directly interconnected with a silicon chip. (b) Integration of flexible microelectrode array onto a cuff electrode designed for acute stimulation of the sub-millimeter nerves. (c) The TiN electrodes exhibited capacitive charge transfer, a water window of -0.6 V to 0.8 V, and a maximum charge injection capacity of 154 ± 16 µC cm-2. SIGNIFICANCE: We present the concept, fabrication and characterization of composite and flexible cuff electrodes, compatible with post-processing and MEMS packaging technologies, which allow for compact integration with control, readout and RF electronics. The fabricated TiN microelectrodes were electrochemically characterized and exhibited a comparable performance to other state-of-the-art electrodes for neural stimulation and recording. Therefore, the presented TiN-on-polyimide microelectrodes, released from silicon wafers, are a promising solution for neural interfaces targeted at sub-millimeter nerves, which may benefit from future upgrades with die-electronic modules.

Diagnostic criteria and prevalence of mild cognitive impairment in older adults living in the community: a systematic review and meta-analysis

Abstract Background Mild Cognitive Impairment (MCI) is a disorder in which the patient presents a cognitive decline, but without negative impact on the activities of daily living. Objective To carry out a systematic review of published studies that analyzed the prevalence of Mild Cognitive Impairment (MCI) in older adults living in the community, and the criteria used for the diagnosis of this disorder. Methods A search was carried out in May 2017 using the descriptors: "epidemiology" or "prevalence", "mild cognitive impairment", and "community" in the PubMed, PsycInfo, SciELO, Web of Science, and Scopus databases. Two independent researchers extracted and documented the data. We used a random effect model to calculate pooled prevalence of MCI for overall studies and for each subgroup divided by diagnostic criteria. Results We found initially 1996 articles, and we selected 35 studies. The prevalence of MCI in the selected studies ranged from 0.5% to 41.8%. The overall pooled prevalence of MCI was 17.3% (CI 95%, 13.8-20.8), with significant heterogeneity between estimates (I2 = 99.6%). Discussion The standardization of the diagnostic criteria for MCI, as well as the tests used in the cognitive evaluation, could allow the comparison between the studies and would be an important step in the researches of this area.

Artepillin C and phenolic compounds responsible for antimicrobial and antioxidant activity of green propolis and Baccharis dracunculifolia DC.

AIMS: This study investigates the antimicrobial activity in Staphylococcus aureus isolates (methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA)) and antioxidant activity of green propolis, Baccharis dracunculifolia DC extracts and Artepillin C™. METHODS AND RESULTS: The amount of Artepillin C in different extracts was determined by high performance liquid chromatography analysis. Minimum inhibitory concentration 90 (MIC90) was determined using 40 isolates of S. aureus inoculated in Müeller-Hinton agar culture medium containing the green propolis and B. dracunculifolia DC extracts. PVEE (green propolis ethanolic extract) and BDEH (B. dracunculifolia hexanic extract) showed the greatest antimicrobial activity with MIC90 values of 246·3 and 295·5 µg ml-1 respectively. Green propolis ethanolic and hexanic extracts (PVEE and PVEH respectively) showed the greatest antioxidant activity assessed by DPPH (1,1-diphenyl-2-picryl hydrazyl radical) with IC50 values of 13·09 and 95·86 µg ml-1 respectively. CONCLUSIONS: Green propolis ethanolic displays better antimicrobial and antioxidant activities compared to other extracts. These activities may be related to the presence of Artepillin C in synergism with the other constituents of the extracts. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, the antimicrobial activity of the extracts of green propolis and B. dracunculifolia DC demonstrated in MRSA and MSSA clinical isolates indicated that they can be important tools to treat infections caused by these bacteria.

Heterotrophic flagellates (Amorpha and Diaphoretiches) in phytotelmata bromeliad (Bromeliaceae)

Abstract Many plants may accumulate rainwater, forming phytotelmata, aquatic microhabitats inhabited by various organisms. The aim of this study was to conduct an inventory of heterotrophic flagellates associated with phytotelmata of the bromeliad Aechmea distichantha Lem., found in rocky cliffs on the Upper Paraná River. The bromeliads were removed manually from the rocky wall, the water was removed and cultures of organisms of each plant were mounted in Petri dishes. Sixteen species of heterotrophic flagellate were recorded, drawn and described, among them one species belonging to the Amorpha Domain and 15 species to the Diaphoretiches Domain. The groups with most species were Euglenida and Kinetoplastea. The low diversity of heterotrophic flagellates recorded in this study, compared to the plankton of lakes and reservoirs, is probably related to the fact that phytotelmata are habitats with extreme environmental conditions, thus selecting organisms tolerant to these environments.

Resumo Em sua superfície externa, muitas plantas podem acumular água da chuva formando fitotelmata, ou seja, micro-habitat aquáticos colonizados por diversos organismos, entre eles, os flagelados protistas. Fez-se um inventário de flagelados heterotróficos associados ao fitotelmata da bromélia Aechmea distichantha Lem., encontrada em paredões rochosos em um trecho da bacia do alto rio Paraná. As bromélias foram retiradas manualmente de paredão rochoso e, em laboratório, a água foi retirada dos tanques de cada planta, e foram montadas culturas dos organismos em placas de Petri. Os flagelados heterotróficos foram, então, observados in vivo sob microscópio óptico Olympus BX51, com sistema de contraste de interferência diferencial (DIC) acoplado. Dezesseis espécies flagelados heterotróficos foram registradas, desenhadas e descritas, sendo uma espécie pertencente ao Domínio Amorpha e 15 espécies ao Domínio Diaphoretiches. Os grupos mais especiosos foram Euglenida e Kinetoplastea. A diversidade relativamente reduzida de flagelados heterotróficos, quando comparada ao plâncton de lagos e reservatórios, pode estar relacionada ao fato de os fitotelmata serem habitats limitados, com condições ambientais extremas, selecionando, assim, organismos tolerantes a esses ambientes.

Electrochemical communication with the inside of cells using micro-patterned vertical carbon nanofibre electrodes.

With the rapidly increasing demands for ultrasensitive biodetection, the design and applications of new nano-scale materials for development of sensors based on optical and electrochemical transducers have attracted substantial interest. In particular, given the comparable sizes of nanomaterials and biomolecules, there exist plenty of opportunities to develop functional nanoprobes with biomolecules for highly sensitive and selective biosensing, shedding new light on cellular behaviour. Towards this aim, herein we interface cells with patterned nano-arrays of carbon nanofibers forming a nanosensor-cell construct. We show that such a construct is capable of electrochemically communicating with the intracellular environment.

Nafion-stabilised bimetallic Pt-Cr nanoparticles as electrocatalysts for proton exchange membrane fuel cells (PEMFCs).

The current study investigated the unique combination of alloying (Pt with Cr) and Nafion stabilisation to reap the benefits of catalyst systems with enhanced catalytic activity and improved durability in PEMFCs. Pt-Cr alloy nanoparticles stabilised with Nafion were chosen in the current study owing to their higher stability in acidic and oxidising media at high temperatures compared to other Pt-transition metal alloys (e.g. Pt-Ni, Pt-Co). Two different precursor : reducing agent (1 : 10 and 1 : 20) ratios were used in order to prepare two different alloys, denoted as Pt-Cr 10 and Pt-Cr 20. The Pt-Cr 20 alloy system (with composition Pt80Cr20) demonstrated higher electrocatalytic activity for the oxygen reduction reaction compared to commercial Pt/C (TKK) catalysts. Accelerated stress tests and single cell tests revealed that Nafion stabilised alloy catalyst systems displayed significantly enhanced durability (only ∼20% loss of ECSA) compared with Pt/C (50% loss of ECSA) due to improved catalyst-ionomer interaction. Furthermore, the Pt-Cr 20 alloy system demonstrated a current density comparable to that of Pt/C making them promising potential electrocatalysts for proton exchange membrane fuel cells.

Modelling zinc changes at the hippocampal mossy fiber synaptic cleft.

Zinc, a transition metal existing in very high concentrations in the hippocampal mossy fibers from CA3 area, is assumed to be co-released with glutamate and to have a neuromodulatory role at the corresponding synapses. The synaptic action of zinc is determined both by the spatiotemporal characteristics of the zinc release process and by the kinetics of zinc binding to sites located in the cleft area, as well as by their concentrations. This work addresses total, free and complexed zinc concentration changes, in an individual synaptic cleft, following single, short and long periods of evoked zinc release. The results estimate the magnitude and time course of the concentrations of zinc complexes, assuming that the dynamics of the release processes are similar to those of glutamate. It is also considered that, for the cleft zinc concentrations used in the model (≤ 1 µM), there is no postsynaptic zinc entry. For this reason, all released zinc ends up being reuptaken in a process that is several orders of magnitude slower than that of release and has thus a much smaller amplitude. The time derivative of the total zinc concentration in the cleft is represented by the difference between two alpha functions, corresponding to the released and uptaken components. These include specific parameters that were chosen assuming zinc and glutamate co-release, with similar time courses. The peak amplitudes of free zinc in the cleft were selected based on previously reported experimental cleft zinc concentration changes evoked by single and multiple stimulation protocols. The results suggest that following a low amount of zinc release, similar to that associated with one or a few stimuli, zinc clearance is mainly mediated by zinc binding to the high-affinity sites on the NMDA receptors and to the low-affinity sites on the highly abundant GLAST glutamate transporters. In the case of higher zinc release brought about by a larger group of stimuli, most zinc binding occurs essentially to the GLAST transporters, having the corresponding zinc complex a maximum concentration that is more than one order of magnitude larger than that for the high and low affinity NMDA sites. The other zinc complexes considered in the model, namely those formed with sites on the AMPA receptors, calcium and KATP channels and with ATP molecules, have much smaller contributions to the synaptic zinc clearance.