Astrocytic aerobic glycolysis provides lactate to support neuronal oxidative metabolism in the hippocampus.

Under physiological conditions, the energetic demand of the brain is met by glucose oxidation. However, ample evidence suggests that lactate produced by astrocytes through aerobic glycolysis may also be an oxidative fuel, highlighting the metabolic compartmentalization between neural cells. Herein, we investigate the roles of glucose and lactate in oxidative metabolism in hippocampal slices, a model that preserves neuron-glia interactions. To this purpose, we used high-resolution respirometry to measure oxygen consumption (O2 flux) at the whole tissue level and amperometric lactate microbiosensors to evaluate the concentration dynamics of extracellular lactate. We found that lactate is produced from glucose and transported to the extracellular space by neural cells in hippocampal tissue. Under resting conditions, endogenous lactate was used by neurons to support oxidative metabolism, which was boosted by exogenously added lactate even in the presence of excess glucose. Depolarization of hippocampal tissue with high K+ significantly increased the rate of oxidative phosphorylation, which was accompanied by a transient decrease in extracellular lactate concentration. Both effects were reverted by inhibition of the neuronal lactate transporter, monocarboxylate transporters 2 (MCT2), supporting the concept of an inward flux of lactate to neurons to fuel oxidative metabolism. We conclude that astrocytes are the main source of extracellular lactate which is used by neurons to fuel oxidative metabolism, both under resting and stimulated conditions.

A Platinized Carbon Fiber Microelectrode-Based Oxidase Biosensor for Amperometric Monitoring of Lactate in Brain Slices.

BACKGROUND: Direct and real-time monitoring of lactate in the extracellular space can help elucidate the metabolic and modulatory role of lactate in the brain. Compared to in vivo studies, brain slices allow the investigation of the neural contribution separately from the effects of cerebrovascular response and permit easy control of recording conditions. METHODS: We have used a platinized carbon fiber microelectrode platform to design an oxidase-based microbiosensor for monitoring lactate in brain slices with high spatial and temporal resolution operating at 32 °C. Lactate oxidase (Aerococcus viridans) was immobilized by crosslinking with glutaraldehyde and a layer of polyurethane was added to extend the linear range. Selectivity was improved by electropolymerization of m-phenylenediamine and concurrent use of a null sensor. RESULTS: The lactate microbiosensor exhibited high sensitivity, selectivity, and optimal analytical performance at a pH and temperature compatible with recording in hippocampal slices. Evaluation of operational stability under conditions of repeated use supports the suitability of this design for up to three repeated assays. CONCLUSIONS: The microbiosensor displayed good analytical performance to monitor rapid changes in lactate concentration in the hippocampal tissue in response to potassium-evoked depolarization.

Design and Evaluation of a Lactate Microbiosensor: Toward Multianalyte Monitoring of Neurometabolic Markers In Vivo in the Brain.

Direct in vivo measurements of neurometabolic markers in the brain with high spatio-temporal resolution, sensitivity, and selectivity is highly important to understand neurometabolism. Electrochemical biosensors based on microelectrodes are very attractive analytical tools for continuous monitoring of neurometabolic markers, such as lactate and glucose in the brain extracellular space at resting and following neuronal activation. Here, we assess the merits of a platinized carbon fiber microelectrode (CFM/Pt) as a sensing platform for developing enzyme oxidase-based microbiosensors to measure extracellular lactate in the brain. Lactate oxidase was immobilized on the CFM/Pt surface by crosslinking with glutaraldehyde. The CFM/Pt-based lactate microbiosensor exhibited high sensitivity and selectivity, good operational stability, and low dependence on oxygen, temperature, and pH. An array consisting of a glucose and lactate microbiosensors, including a null sensor, was used for concurrent measurement of both neurometabolic substrates in vivo in the anesthetized rat brain. Rapid changes of lactate and glucose were observed in the cortex and hippocampus in response to local glucose and lactate application and upon insulin-induced fluctuations of systemic glucose. Overall, these results indicate that microbiosensors are a valuable tool to investigate neurometabolism and to better understand the role of major neurometabolic markers, such as lactate and glucose.

An optimized spectrophotometric assay reveals increased activity of enzymes involved in 2-arachidonoyl glycerol turnover in the cerebral cortex of a rat model of Alzheimer's disease.

The endocannabinoid system is implicated in a plethora of neuropsychiatric disorders. However, it is technically challenging to assess the turnover of 2-arachidonoyl glycerol (2-AG), the principal endocannabinoid molecule in the brain. Two recent studies showed that diacylglycerol lipase α (DAGLα), an enzyme chiefly responsible for the cerebral production of 2-AG, also accepts the surrogate chromogenic substrate 4-nitrophenyl butyrate (4-NPB). Here, we aimed to optimize this spectrophotometric assay for ex vivo brain tissue, in particular, rat cerebrocortical homogenates, to measure the activity of the major enzymes responsible for the production and degradation of 2-AG. The initial velocity of 4-NPB hydrolysis was dependent on protein, substrate, and Ca2+ concentrations, and was sensitive to the non-selective serine hydrolase inhibitor, methoxy arachidonyl fluorophosphonate, the DAGLα inhibitors, OMDM188, tetrahydrolipstatin, and RHC80267, as well as the monoacylglycerol lipase (MAGL) inhibitor, JZL184, respectively. Next, we tested the usefulness of this assay in ex vivo brain tissue of rat models of human health conditions known to affect cerebrocortical 2-AG production, i.e. pathological stress and sporadic Alzheimer's disease (AD). In rats submitted to chronic restraint stress, cortical CB1 R density was significantly decreased, as assessed with radioligand binding. Nevertheless, 4-NPB hydrolysis remained at control levels. However, in rats 4 weeks after intracerebroventricular injection with streptozotocin - an established model of sporadic AD -, both CB1 R levels and 4-NPB hydrolysis and its DAGL- and MAGL-dependent fractions were significantly increased. Altogether, we optimized a simple complementary ex vivo technique for the quantification of DAGL and MAGL activity in brain samples.

Highly sensitive and selective nanostructured microbiosensors for glucose and lactate simultaneous measurements in blood serum and in vivo in brain tissue.

Highly sensitive and selective nanostructured lactate and glucose microbiosensors for their in vivo simultaneous determination in rat brain were developed based on carbon fiber microelectrodes (CFM) modified with nanoporous gold (NPG) using the Dynamic Hydrogen Bubble Template (DHBT) method. Electrodeposition of platinum nanoparticles (PtNP) onto the NPG film enhances the sensitivity and the electrocatalytic properties towards H2O2 detection. The nanostructured microelectrode platform was modified by glucose oxidase (GOx) and lactate oxidase (LOx) enzyme immobilization. High selective measurements were achieved by covering with a perm-selective layer of electropolymerized m-phenylenediamine, deposition of a Nafion® film and by using a null sensor. The morphological characteristics and electroanalytical performance of the microbiosensors were assessed, by scanning electron microscopy and electrochemical techniques, respectively. The PtNP/NPG/CFM shows a high sensitivity to H2O2 (5.96 A M-1 cm-2) at 0.36 V vs. Ag/AgCl, with a linear range from 0.2 to 200 µM, and an LOD of 10 nM. The microbiosensors were applied to the simultaneous determination of lactate and glucose in blood serum samples. Moreover, the basal extracellular concentrations of lactate and glucose were measured in vivo in four different rat brain structures. These results support the potential of the microbiosensor to be used as a valuable tool to investigate brain neurochemicals in vivo.

Microelectrode Sensor for Real-Time Measurements of Nitrite in the Living Brain, in the Presence of Ascorbate.

The impaired blood flow to the brain causes a decrease in the supply of oxygen that can result in cerebral ischemia; if the blood flow is not restored quickly, neuronal injury or death will occur. Under hypoxic conditions, the production of nitric oxide (●NO), via the classical L-arginine-●NO synthase pathway, is reduced, which can compromise ●NO-dependent vasodilation. However, the alternative nitrite (NO2-) reduction to ●NO, under neuronal hypoxia and ischemia conditions, has been viewed as an in vivo storage pool of ●NO, complementing its enzymatic synthesis. Brain research is thus demanding suitable tools to probe nitrite's temporal and spatial dynamics in vivo. In this work, we propose a new method for the real-time measurement of nitrite concentration in the brain extracellular space, using fast-scan cyclic voltammetry (FSCV) and carbon microfiber electrodes as sensing probes. In this way, nitrite was detected anodically and in vitro, in the 5-500 µM range, in the presence of increasing physiological concentrations of ascorbate (100-500 µM). These sensors were then tested for real-time and in vivo recordings in the anesthetized rat hippocampus; using fast electrochemical techniques, local and reproducible transients of nitrite oxidation signals were observed, upon pressure ejection of an exogenous nitrite solution into the brain tissue. Nitrite microsensors are thus a valuable tool for investigating the role of this inorganic anion in brain redox signaling.

A High Fat/Cholesterol Diet Recapitulates Some Alzheimer's Disease-Like Features in Mice: Focus on Hippocampal Mitochondrial Dysfunction.

BACKGROUND: Ample evidence from clinical and pre-clinical studies suggests mid-life hypercholesterolemia as a risk factor for developing Alzheimer's disease (AD) at a later age. Hypercholesterolemia induced by dietary habits can lead to vascular perturbations that increase the risk of developing sporadic AD. OBJECTIVE: To investigate the effects of a high fat/cholesterol diet (HFCD) as a risk factor for AD by using a rodent model of AD and its correspondent control (healthy animals). METHODS: We compared the effect of a HFCD in normal mice (non-transgenic mice, NTg) and the triple transgenic mouse model of AD (3xTgAD). We evaluated cognitive performance in relation to changes in oxidative metabolism and neuron-derived nitric oxide (•NO) concentration dynamics in hippocampal slices as well as histochemical staining of markers of the neurovascular unit. RESULTS: In NTg, the HFCD produced only moderate hypercholesterolemia but significant decline in spatial memory was observed. A tendency for decrease in •NO production was accompanied by compromised mitochondrial function with decrease in spare respiratory capacity. In 3xTgAD mice, a robust increase in plasma cholesterol levels with the HFCD did not worsen cognitive performance but did induce compromise of mitochondrial function and significantly decreased •NO production. We found increased staining of biomarkers for astrocyte endfeet and endothelial cells in 3xTgAD hippocampi, which was further increased by the HFCD. CONCLUSION: A short term (8 weeks) intervention with HFCD can produce an AD-like phenotype even in the absence of overt systemic hypercholesterolemia and highlights mitochondrial dysfunction as a link between hypercholesterolemia and sporadic AD.

The Peculiar Facets of Nitric Oxide as a Cellular Messenger: From Disease-Associated Signaling to the Regulation of Brain Bioenergetics and Neurovascular Coupling.

In this review, we address the regulatory and toxic role of ·NO along several pathways, from the gut to the brain. Initially, we address the role on ·NO in the regulation of mitochondrial respiration with emphasis on the possible contribution to Parkinson's disease via mechanisms that involve its interaction with a major dopamine metabolite, DOPAC. In parallel with initial discoveries of the inhibition of mitochondrial respiration by ·NO, it became clear the potential for toxic ·NO-mediated mechanisms involving the production of more reactive species and the post-translational modification of mitochondrial proteins. Accordingly, we have proposed a novel mechanism potentially leading to dopaminergic cell death, providing evidence that NO synergistically interact with DOPAC in promoting cell death via mechanisms that involve GSH depletion. The modulatory role of NO will be then briefly discussed as a master regulator on brain energy metabolism. The energy metabolism in the brain is central to the understanding of brain function and disease. The core role of ·NO in the regulation of brain metabolism and vascular responses is further substantiated by discussing its role as a mediator of neurovascular coupling, the increase in local microvessels blood flow in response to spatially restricted increase of neuronal activity. The many facets of NO as intracellular and intercellular messenger, conveying information associated with its spatial and temporal concentration dynamics, involve not only the discussion of its reactions and potential targets on a defined biological environment but also the regulation of its synthesis by the family of nitric oxide synthases. More recently, a novel pathway, out of control of NOS, has been the subject of a great deal of controversy, the nitrate:nitrite:NO pathway, adding new perspectives to ·NO biology. Thus, finally, this novel pathway will be addressed in connection with nitrate consumption in the diet and the beneficial effects of protein nitration by reactive nitrogen species.

Electrochemical Evaluation of a Multi-Site Clinical Depth Recording Electrode for Monitoring Cerebral Tissue Oxygen.

The intracranial measurement of local cerebral tissue oxygen levels-PbtO2-has become a useful tool for the critical care unit to investigate severe trauma and ischemia injury in patients. Our preliminary work in animal models supports the hypothesis that multi-site depth electrode recording of PbtO2 may give surgeons and critical care providers needed information about brain viability and the capacity for better recovery. Here, we present a surface morphology characterization and an electrochemical evaluation of the analytical properties toward oxygen detection of an FDA-approved, commercially available, clinical grade depth recording electrode comprising 12 Pt recording contacts. We found that the surface of the recording sites is composed of a thin film of smooth Pt and that the electrochemical behavior evaluated by cyclic voltammetry in acidic and neutral electrolyte is typical of polycrystalline Pt surface. The smoothness of the Pt surface was further corroborated by determination of the electrochemical active surface, confirming a roughness factor of 0.9. At an optimal working potential of -0.6 V vs. Ag/AgCl, the sensor displayed suitable values of sensitivity and limit of detection for in vivo PbtO2 measurements. Based on the reported catalytical properties of Pt toward the electroreduction reaction of O2, we propose that these probes could be repurposed for multisite monitoring of PbtO2 in vivo in the human brain.

Automated classification of normal and Stargardt disease optical coherence tomography images using deep learning.

PURPOSE: Recent advances in deep learning have seen an increase in its application to automated image analysis in ophthalmology for conditions with a high prevalence. We wanted to identify whether deep learning could be used for the automated classification of optical coherence tomography (OCT) images from patients with Stargardt disease (STGD) using a smaller dataset than traditionally used. METHODS: Sixty participants with STGD and 33 participants with a normal retinal OCT were selected, and a single OCT scan containing the centre of the fovea was selected as the input data. Two approaches were used: Model 1 - a pretrained convolutional neural network (CNN); Model 2 - a new CNN architecture. Both models were evaluated on their accuracy, sensitivity, specificity and Jaccard similarity score (JSS). RESULTS: About 102 OCT scans from participants with a normal retinal OCT and 647 OCT scans from participants with STGD were selected. The highest results were achieved when both models were implemented as a binary classifier: Model 1 - accuracy 99.6%, sensitivity 99.8%, specificity 98.0% and JSS 0.990; Model 2 - accuracy 97.9%, sensitivity 97.9%, specificity 98.0% and JSS 0.976. CONCLUSION: The deep learning classification models used in this study were able to achieve high accuracy despite using a smaller dataset than traditionally used and are effective in differentiating between normal OCT scans and those from patients with STGD. This preliminary study provides promising results for the application of deep learning to classify OCT images from patients with inherited retinal diseases.

Cryopreservation of Brazilian green dwarf coconut plumules by droplet-vitrification / Criopreservação de coqueiro anão verde do Brasil de Jiqui por vitrificação em gotas

ABSTRACT: This study evaluated the effect of vitrification solutions and exposure time on the cryopreservation of Brazilian green dwarf coconut plumules (BGD) using the droplet vitrification technique. Explants were excised from BGD mature fruits from the Active Germplasm Bank of Embrapa Tabuleiros Costeiros, Sergipe, Brazil. Firstly, embryos were disinfected, and after excision, plumules were pre-cultivated for 72 hours in Y3 + 0.6 M sucrose + 2.2 g L-1 Gelrite® culture medium. Plumules were exposed to PVS2 and PVS3 solutions for 15 and 30 minutes and rapidly immersed in liquid nitrogen (-196 ºC). After cryopreservation, they were thawed in culture medium solution (Y3 + 1.2 M sucrose) and cultured in regeneration medium. The experimental design was completely randomized in a 2x2 factorial scheme (vitrification solutions per exposure times), with five replicates per treatment. Data were compared by the Tukey's test at 5% probability. Significant differences were observed in the callogenesis percentage for the solutions x exposure time interaction for non-cryopreserved cultures (-NL) and for exposure time after cryopreservation (+NL). PVS2 and PVS3 combined with 15 minutes of exposure promoted the highest callus formation (70 and 100%, respectively) in control cultures. The exposure time of 30 min, regardless of vitrification solution, resulted in 30% embryogenic callus formation after cryopreservation. These results contributed to the long-term conservation of coconut palm.

RESUMO: O objetivo desse estudo foi avaliar o efeito das soluções de vitrificação e do tempo de exposição na criopreservação de plúmulas de coqueiro anão verde do Brasil de Jiqui (BGD), pela técnica de vitrificação em gotas. Os explantes foram excisados de frutos maduros oriundos do Banco de Germoplasma Ativo de Embrapa Tabuleiros Costeiros, Sergipe, Brasil. Os embriões foram desinfestados e as plúmulas, após a excisão, pré-cultivadas durante 72 horas em meio de cultura Y3 suplementado com sacarose 0,6 e 2,2 g L-1 Gelrite®. As plúmulas foram expostas em soluções de PVS2 e PVS3 durante 15 e 30 minutos, e rapidamente imersas em nitrogênio líquido (-196 ºC). Após a criopreservação, foram descongeladas na solução de meio de cultura Y3 com 1,2 M de sacarose, e cultivadas em meio de regeneração. O delineamento experimental foi inteiramente casualizado em esquema fatorial 2x2 (soluções de vitrificação x tempos de exposição), com cinco repetições por tratamento. Os dados foram comparados pelo teste de Tukey à probabilidade de 5%. Observaram-se diferenças significativas na porcentagem de calogênese para a interação entre soluções e tempo de exposição para as culturas não criopreservadas (-NL), e para o tempo de exposição após a criopreservação (+NL). O PVS2 e o PVS3 combinados com 15 minutos promoveram a maior formação de calo (70 e 100%, respectivamente) nas culturas de controle. O tempo de exposição de 30 min, independente da solução de vitrificação, promoveu 30% da formação de calos embriogênicos após a criopreservação. Estes resultados contribuem para a conservação em longo prazo do coqueiro.

Changes health-related quality of life in HIV-infected patients following initiation of antiretroviral therapy: a longitudinal study

Abstract Background: Several tools have been developed to evaluate HIV health-related quality of life (HRQoL) during and after antiretroviral therapy (ART). Few longitudinal studies evaluated the effect of ART on the quality of life of HIV patients. Objective: To evaluate changes in HRQoL in HIV-infected individuals one year after initiating ART. Methods: A prospective study was conducted from May 2016 to July 2018. Data on clinical and sociodemographic characteristics of 91 HIV-infected patients were collected prior to initiation of ART and one year thereafter. Demographic and clinical data were collected and the questionnaires 36-item Short Form Health Survey (SF-36) and HIV/AIDS-targeted quality of life (HAT-QoL) were administered in both periods. Asymptomatic individuals, aged ≥18 years, were included in the study. Patients who discontinued treatment were excluded. The association between predictors of physical and mental HRQoL was analyzed by multiple linear regression analysis. Results: Patients were predominantly male (78.0%), mean age 35.3 ± 10.7 years, with no stable relationship (80.2%), and no comorbidities (73.6%). Most of the SF-36 domains improved after one year, particularly Physical Function (p = 0.0001), General Health (p = 0.0001), Social Functioning (p = 0.0001), Mental Health (p = 0.001), and Mental Component Summary (p = 0.004). HAT-QoL domains improved in the Overall Function (p = 0.0001), Life Satisfaction (p = 0.0001), Provider Trust (p = 0.001), and Sexual Function (p = 0.0001) domains. Sex (p = 0.032), age (p = 0.001), income (p = 0.007), and stable relationship (p = 0.004) were good predictors of the Physical Component Summary. Sex (p = 0.002) and stable relationship (p = 0.038) were good predictors of the Mental Component Summary. SF-36 and HAT-QoL scales presented strong correlations, except for Medication Concerns (0.15-0.37), HIV Mastery (0.18-0.38), Disclosure Worries (−0.15 to 0.07), and Provider Trust (−0.07 to 0.15). Conclusions: ART improved HRQoL after one year of use. The HAT-QoL and SF-36 correlated well and are good tools to evaluate HRQoL in HIV-infected patients on ART.

Platinized carbon fiber-based glucose microbiosensor designed for metabolic studies in brain slices.

In order to understand how energy metabolism adapts to changes in neuronal activity it is imperative to perform direct measurements of the flux of glucose (and other metabolites) in brain tissue. Metabolic studies using brain slice preparations are attractive due to the controllability of recording conditions, absence of anesthetic interference and refined animal experimental protocols. In this work, taking advantage of the small size and versatility of carbon fiber microelectrodes (CFMs), we aimed to develop an amperometric glucose microbiosensor suitable for glucose measurement in brain slices. Potentiostatic- or galvanostatic-driven platinum electrodeposition was used to improve the analytical properties of CFMs towards detection of hydrogen peroxide. The platinized CFMs served as platform for the development of glucose microbiosensors through the immobilization of glucose-oxidase (GOx) by cross-linking with glutaraldehyde in the presence of BSA. Selective glucose measurements were attained by modifying the electrode with a permselective layer of meta-phenylenediamine and by integrating a null sensor. The in vitro characterization studies support the good analytical features of the CFM/Pt-based microbiosensors to reliably measure glucose in brain tissue. The ex vivo experiments in rodent hippocampal slices validated their suitability to measure evoked changes in extracellular glucose. This approach, encompassing the use of null sensor to cross-check the selectivity on a moment-to-moment basis, allowed us to provide the temporal and quantitative profile of extracellular glucose changes in hippocampal slices following a spreading depolarization event. Overall, these results support the potential of these microbiosensors to be used as a valuable tool to investigate the complex nature of glucose utilization in brain tissue linked to neuronal activation both in physiological and pathological conditions.

Changes health-related quality of life in HIV-infected patients following initiation of antiretroviral therapy: a longitudinal study.

BACKGROUND: Several tools have been developed to evaluate HIV health-related quality of life (HRQoL) during and after antiretroviral therapy (ART). Few longitudinal studies evaluated the effect of ART on the quality of life of HIV patients. OBJECTIVE: To evaluate changes in HRQoL in HIV-infected individuals one year after initiating ART. METHODS: A prospective study was conducted from May 2016 to July 2018. Data on clinical and sociodemographic characteristics of 91 HIV-infected patients were collected prior to initiation of ART and one year thereafter. Demographic and clinical data were collected and the questionnaires 36-item Short Form Health Survey (SF-36) and HIV/AIDS-targeted quality of life (HAT-QoL) were administered in both periods. Asymptomatic individuals, aged ≥18 years, were included in the study. Patients who discontinued treatment were excluded. The association between predictors of physical and mental HRQoL was analyzed by multiple linear regression analysis. RESULTS: Patients were predominantly male (78.0%), mean age 35.3 ±â€¯10.7 years, with no stable relationship (80.2%), and no comorbidities (73.6%). Most of the SF-36 domains improved after one year, particularly Physical Function (p = 0.0001), General Health (p = 0.0001), Social Functioning (p = 0.0001), Mental Health (p = 0.001), and Mental Component Summary (p = 0.004). HAT-QoL domains improved in the Overall Function (p = 0.0001), Life Satisfaction (p = 0.0001), Provider Trust (p = 0.001), and Sexual Function (p = 0.0001) domains. Sex (p = 0.032), age (p = 0.001), income (p = 0.007), and stable relationship (p = 0.004) were good predictors of the Physical Component Summary. Sex (p = 0.002) and stable relationship (p = 0.038) were good predictors of the Mental Component Summary. SF-36 and HAT-QoL scales presented strong correlations, except for Medication Concerns (0.15-0.37), HIV Mastery (0.18-0.38), Disclosure Worries (-0.15 to 0.07), and Provider Trust (-0.07 to 0.15). CONCLUSIONS: ART improved HRQoL after one year of use. The HAT-QoL and SF-36 correlated well and are good tools to evaluate HRQoL in HIV-infected patients on ART.

Proline synthesis and physiological response of cassava genotypes under in vitro salinity / Síntese de prolina e resposta fisiológica de genótipos de mandioca sob salinidade in vitro

ABSTRACT: The objective of this research was to evaluate the proline synthesis and physiological response of cassava genotypes which were micro propagated and induced to salinity stress in vitro. Micro cuttings of approximately 1.0cm long with a single bud of genotypes TBRS Tapioqueira, BRS Verdinha and Lagoão which were previously established in vitro were inoculated in a MS medium containing different concentrations of NaCl (0; 25; 50; 75; 100mM) and were analyzed after 90th day for: number of roots, number of leaves and shoot dry mass. The proline content of BRS Tapioqueira and Lagoão was assessed at 30th, 60th and 90th day. There was no analysis of proline of the variety Verdinha because of the contamination of the explants. The experimental design was completely randomized in double factorial scheme (3 genotypes x 5 salt treatments), with seven repetitions for growth variables. For comparing proline content, completely randomized design was used in a plot subdivided in time, with genotype and NaCl factors in plot and time in subplot, with two repetitions. For r time and genotypes Tukey test (P<0,05) was used and for NaCl levels regression test (P<0,05). Salinity affected the growth of all varieties; although, BRS Tapioqueira and BRS Verdinha were less affected by induced salt stress. There was an increase in the accumulation of proline from the salt increment, this synthesis of proline being a biochemical indicator of salt stress in cassava plants cultivated in vitro.

RESUMO: O objetivo deste trabalho foi avaliar a síntese de prolina e respostas fisiológicas de variedades de mandioca micropropagadas e induzidas ao estresse salino in vitro. Microestacas das variedades BRS Tapioqueira, BRS Verdinha e Lagoão previamente estabelecidas in vitro foram inoculadas em meio MS com diferentes concentrações de NaCl (0; 25; 50; 75; 100mM) e aos 90 dias foram analisados: número de raiz, número de folhas e massa seca de parte aérea. O teor de prolina das variedades BRS Tapioqueira e Lagoão foi analisado aos 30, 60 e 90 dias. Não houve análise de prolina da variedade Verdinha por causa da contaminação dos explantes. O delineamento experimental foi inteiramente casualizado em esquema fatorial 3 genótipos x 5 tratamentos salinos, com sete repetições para as variáveis de crescimento. Para o conteúdo de prolina foi considerado inteiramente casualizado subdividido no tempo, com genótipos e NaCl na parcela e o tempo na subparcela e duas repetições. Para os fatores variedade e tempo, foi utilizado o teste de Tukey (P<0,05) e para tratamentos salinos, teste de Regressão (P<0,05). A salinidade afetou o crescimento de todas as variedades, porém BRS Tapioqueira e BRS Verdinha mostraram-se menos afetadas pelo estresse salino induzido. Houve aumento no acúmulo de prolina a partir do incremento de sal, sendo então este, um indicador bioquímico de estresse salino em plantas de mandioca cultivadas in vitro.

Biochemical, physiological and growth changes in response to in vitro salinity in sugarcane / Alterações bioquímicas, fisiológicas e de crescimento em resposta à salinidade in vitro em cana-de-açúcar

Abiotic stresses in plants have aroused great research interest, unceasingly seeking for more productive cultivars under unfavorable cultivation conditions. Water deficiency and soil salinity are the most studied aspects, due to their strong impact on the growth and productivity of plants. The objective of this study was to evaluate accessions of different sugarcane species (Saccharum spp., S. robustum, S. officinarum) regarding tolerance to in vitrosalinity, from changes in physiological, anatomical, biochemical and biometric parameters, to assist in breeding programs. To this end, shoots were used, grown on Murashige and Skoog medium, supplemented with 2% of sucrose and 4 g.L-1Phytagel, in the presence of five concentrations 0, 50, 100, 150, 200 mM NaCl. Shoots length, roots length, shoots number, roots number, fresh weight, dry weight, proline content in leaves, total chlorophyll content, and morphological changes to the leaf tissue were analyzed. The in vitro growth of accessions Saccharum robustum, Saccharum spp. and Saccharum officinarum are affected by salinity induced by NaCl. The proline accumulation and chlorophyll decrease are intensified in Saccharum spp., in addition to changes in cell's anatomy, characterized as more sensitive to salt.(AU)

Os estresses abióticos em plantas têm despertado grande interesse da pesquisa, que tem buscado incessantemente por cultivares mais produtivas sob condições desfavoráveis de cultivo. A deficiência hídrica e a salinidade do solo são os mais estudados, em razão de seu forte impacto sobre o crescimento e a produtividade das plantas. O objetivo deste estudo foi avaliar acessos de diferentes espécies de cana-de-açúcar (Saccharum robustum, Saccharum spp., S. officinarum), quanto a tolerância à salinidade in vitro, a partir de alterações nos parâmetros fisiológicos, anatômicos, bioquímicos e biométricos, para auxiliar em futuros programas de melhoramento. Para tanto foram utilizadas brotações, cultivadas em meio Murashige e Skoog, suplementado com 2% de sacarose e 4 g.L-1 de Phytagel, na presença de cinco concentrações 0, 50, 100, 150, 200 mM de NaCl. Comprimento das brotações e da raiz, número de brotações e de raízes, peso fresco, peso seco, teor de prolina nas folhas, conteúdo de clorofila total e alterações morfológicas dos tecidos foliares foram analisados. O crescimento in vitro dos acessos Saccharum robustum, Saccharum spp. e Saccharum officinarum é afetado pela salinidade induzida por NaCl. O acúmulo de prolina e decréscimo de clorofila é intensificado em Saccharumspp., além de mudança na anatomia de células, caracterizando-se como mais sensível ao sal.(AU)

Induction and growth curve of calli from leaf and nodal explants of genipap / Indução e curva de crescimento de calos obtidos de explantes foliares e nodais de jenipapeiro

The aim of this study was to determine the effect of the auxin 2,4-D (2,4-dichlorophenoxyacetic) in calli formation from leaf and nodal segments of genipap and to characterize its growth curve. Explants obtained from shoots previously established from in vitro seedlings were used for calli induction. The experimental design was completely randomized in a 3x5x2 factorial with three accessions (NB, SA, SAL), five concentrations of 2,4-D (0.0; 2.0; 4.0, 6.0 or 8.0 mg L-1) and two times of measurement for calli fresh weight (30 and 60 days). There was callus formation in all treatments tested. It was observed that the best response for callus induction from leaf segments was with 2.0 mg L-1 of 2,4-D. For the nodal segment, the response among the accessions was different due to 2,4-D concentrations. The growth curve was plotted according to the fresh weight of callus obtained at intervals of 10 days up to 60 days. Through the established growth curve, the nodal-derived calli from accession SA should be transferred to a new medium, after 40 days of culture.

O objetivo desse trabalho foi determinar o efeito da auxina 2,4-D (ácido diclorofenoxiacético) na calogênese de segmentos foliar e nodal de jenipapeiro e caracterizar sua curva de crescimento. Explantes obtidos de brotações pré-estabelecidas a partir de plântulas in vitro foram utilizados na indução de calos. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 3x5x2, com três acessos (NB, SA e SAL), cinco concentrações de 2,4-D (0,0; 2,0; 4,0; 6,0 ou 8,0 mg L-1) e dois tempos de avaliação (30 e 60 dias) da massa fresca de calos. Houve formação de calos em todos os tratamentos testados. Observou-se que a melhor resposta de indução ocorreu na concentração de 2,0 mg L-1 para calos oriundos de segmentos foliares. Para o segmento nodal a resposta entre os acessos foi diferenciada em função das concentrações de 2,4-D. A curva de crescimento foi plotada a partir da massa fresca dos calos obtida em intervalos de 10 dias até os 60 dias. Através da curva de crescimento estabelecida, os calos derivados de segmentos nodais do acesso SA devem ser transferidos para um novo meio de cultura, 40 dias após à inoculação.

Association Between Health-Related Quality of Life and Physical Functioning in Antiretroviral-Naive HIV-Infected Patients.

BACKGROUND: Poor functional status can significantly affect Health-Related Quality of Life (HRQoL) of HIV patients. However, there is scarce information on the functional profile of such patients before starting antiretroviral therapy (ART). OBJECTIVE: To estimate the association between health-related quality of life and physical functioning in Antiretroviral-Naive HIV-infected patients. METHODS: We conducted a cross-sectional study with HIV-infected patients older than 18 years, and naïve to antiretroviral therapy. The patients were evaluated for functional profile by pulmonary function (forced vital capacity, forced expiratory volume at one second, and Tiffeneau index), handgrip strength, and six-minute walk test in a cross-sectional study. HRQoL was evaluated by the 36-Item Short-Form Health Survey and its Physical (PCS) and Mental (MCS) Component Summaries. Multiple linear regression analyses were used to evaluate the association of predictor variables with PCS and MCS scores. RESULTS: We found lower HRQoL among females patients, with far below average impairment of mental health component. Both male and female patients presented lower 6MWD function test values. Patients with dynapenia were older than patients without it, presented lower PCS mean score, lower family income, poor 6 MWD function test, lower FVC, and lower FEV1 t. Multivariable logistic regression analyses showed that Grip Strength, age and family income were predictor variables for Physical component of HRQoL. Female gender and smoking habit were predictive for the mental component of HRQoL. CONCLUSION: HRQoL in HIV, drug-naïve patients is predicted by level of dynapenia, smoking, income and gender. Therefore, lifestyle changes and active exercising can help to improve HRQoL in such patients.

Muscle Strength and Aerobic Capacity in HIV-Infected Patients: A Systematic Review and Meta-Analysis.

BACKGROUND: Physical impairment is highly prevalent in HIV-infected patients. We conducted a systematic review of published studies that included studies comparing muscle function in HIV-infected patients to matched healthy controls, and studies comparing aerobic capacity in HIV-infected patients with that observed in matched healthy controls. DESIGN: Systematic review and meta-analysis. METHODS: We searched for references on MEDLINE, SciELO, Cumulative Index to Nursing and Allied Health (CINAHL), and Scopus up to December 2017. Weighted mean differences and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed using the I test. RESULTS: A total of 30 studies, covering 2148 healthy controls and 2161 HIV-infected patients, fulfilled the inclusion criteria. The average muscle strength and aerobic capacity were significantly lower in HIV-infected patients. Meta-analysis revealed moderate-quality evidence of weaker muscle strength and aerobic capacity in HIV-infected patients. A significant difference in lower-body strength of 1.07 (95% CI: 0.29 to 1.84) was found for participants in the healthy control group compared with HIV group. A significant difference in aerobic capacity (peak VO2) of 8.4 (95% CI: 4.8 to 12.0) was found for participants in the healthy control group compared with HIV group. CONCLUSIONS: Muscle strength and aerobic capacity of HIV-infected patients are reduced in comparison with healthy controls. Additional studies are needed to define the best interventions to improve the physical function in HIV-infected patients.

Age-Dependent Impairment of Neurovascular and Neurometabolic Coupling in the Hippocampus.

Neurovascular and neurometabolic coupling are critical and complex processes underlying brain function. Perturbations in the regulation of these processes are, likely, early dysfunctional alterations in pathological brain aging and age-related neurodegeneration. Evidences support the role of nitric oxide (•NO) as a key messenger both in neurovascular coupling, by signaling from neurons to blood vessels, and in neurometabolic coupling, by modulating O2 utilization by mitochondria. In the present study, we investigated the functionality of neurovascular and neurometabolic coupling in connection to •NO signaling and in association to cognitive performance during aging. For this, we performed in vivo simultaneous measurements of •NO, O2 and cerebral blood flow (CBF) in the hippocampus of F344 rats along chronological age in response to glutamatergic activation and in correlation with cognitive performance. Firstly, it is evidenced the temporal sequence of events upon glutamate stimulation of hippocampal dentate gyrus, encompassing the local and transitory increase of •NO followed by transitory local changes of CBF and pO2. Specifically, the transient increase of •NO is followed by an increase of CBF and biphasic changes of the local pO2. We observed that, although the glutamate-induced •NO dynamics were not significantly affected by aging, the correspondent hemodynamic was progressively diminished accompanying a decline in learning and memory. Noteworthy, in spite of a compromised blood supply, in aged rats we observed an increased ΔpO2 associated to the hemodynamic response, suggestive of a decrease in the global metabolic rate of O2. Furthermore, the impairment in the neurovascular coupling observed along aging in F344 rats was mimicked in young rats by promoting an unbalance in redox status toward oxidation via intracellular generation of superoxide radical. This observation strengthens the idea that oxidative stress may have a critical role in the neurovascular uncoupling underlying brain aging and dysfunction. Overall, data supports an impairment of neurovascular response in connection with cognition decline due to oxidative environment-dependent compromised •NO signaling from neurons to vessels during aging.