Fase premonitoria, una etapa clave en la migraña / The premonitory phase: A crucial stage in migraine

Introducción: La fase premonitoria comprende una amplia esfera de síntomas que anteceden hasta en 48 horas al dolor en una crisis de migraña. Este periodo a menudo no es reconocido por el propio paciente y, sin embargo, también merma de forma significativa su calidad de vida.Al ser el estadio más precoz de una crisis de migraña es fundamental para ayudarnos a comprender puntos clave del origen de la misma.DesarrolloA lo largo de esta revisión, en forma de pregunta-respuesta, se repasan los principales estudios clínicos que analizan de forma dirigida los síntomas premonitorios, se valora la capacidad predictiva de los mismos, se relacionan estos síntomas con la biología de la migraña, se revisa el papel de la neuroimagen en esta fase y, por último, la relevancia como potencial diana terapéutica que pueda tener en un futuro.ConclusionesEl estudio de la fase premonitoria nos ha mostrado que el hipotálamo tiene un papel esencial en el origen de una crisis de migraña, y nos hace plantearnos la búsqueda de nuevas dianas en el tratamiento de una crisis de migraña dirigidas a actuar antes del inicio del dolor, un hecho que implicaría un antes y un después en la vida del paciente migrañoso. (AU)

Introduction: The premonitory phase comprises a wide range of symptoms that precede the onset of pain in a migraine episode by up to 48 hours. Premonitory symptoms are often not recognised by patients but do have a significant impact on their quality of life. As these symptoms represent the first stage of a migraine attack, they are crucial in improving our understanding of the key points of the origin of migraine.DevelopmentThis paper uses a question-answer format to review the main clinical studies analysing premonitory symptoms, their predictive capacity, the relationship between these symptoms and the biology of migraine, and the role of neuroimaging in the premonitory phase. Finally, we discuss the relevance of these symptoms as potential therapeutic targets in the future.ConclusionsThis study of the premonitory phase has demonstrated that the hypothalamus plays an essential role in the origin of migraine attacks. We should consider the search for new targets in acute migraine treatment in order to act before the onset of the pain. This would imply a radical change in the lives of patients with migraine. (AU)

The premonitory phase: A crucial stage in migraine. / Fase premonitoria, una etapa clave en la migraña.

INTRODUCTION: The premonitory phase comprises a wide range of symptoms that precede the onset of pain in a migraine episode by up to 48hours. Premonitory symptoms are often not recognised by patients but do have a significant impact on their quality of life. As these symptoms represent the first stage of a migraine attack, they are crucial in improving our understanding of the key points of the origin of migraine. DEVELOPMENT: This paper uses a question-answer format to review the main clinical studies analysing premonitory symptoms, their predictive capacity, the relationship between these symptoms and the biology of migraine, and the role of neuroimaging in the premonitory phase. Finally, we discuss the relevance of these symptoms as potential therapeutic targets in the future. CONCLUSIONS: This study of the premonitory phase has demonstrated that the hypothalamus plays an essential role in the origin of migraine attacks. We should consider the search for new targets in acute migraine treatment in order to act before the onset of the pain. This would imply a radical change in the lives of patients with migraine.

CALCA and TRPV1 genes polymorphisms are related to a good outcome in female chronic migraine patients treated with OnabotulinumtoxinA.

BACKGROUND: Some variables have been proposed as predictors of efficacy of OnabotulinumtoxinA in chronic migraine patients, but data available are inconclusive. We aimed to analyse the influence of single nucleotide polymorphisms in the response to OnabotulinumtoxinA. METHODS: We included 156 female patients treated with OnabotulinumtoxinA accordingly to PREEMPT paradigm in three headache units. OnabotulinumtoxinA was offered to patients that had not responded to topiramate and at least one other preventative. Age at first procedure was 43.7 ± 11.8 years (16-74). Patients with a reduction of at least 50% in the number of migraine days after two OnabotulinumtoxinA procedures were considered as responders. We analysed 25 polymorphisms selected for their relevance regarding migraine pathophysiology and their association with migraine according to previously published genome-wide association studies. Genotyping was performed using KASP probes and a LightCycler-480 (Roche-Diagnostics). Allelic, genotypic frequencies and dominance/recesivity hypothesis of the allelic variants were compared between responders and non-responders by Fisher's exact test. RESULTS: Response to treatment with OnabotulinumtoxinA was achieved in 120 patients (76,9%). Two polymorphisms showed differences: CALCA rs3781719, where allele C represents 26.9% in responders and 40.9% in non-responders (p = 0.007, OR = 3.11 (1.33-7.26)); and TRPV1 rs222749, where allele A represents 4.17% in responders and 12.5% in non-responders (p = 0.013, OR = 3.29 (1.28-8.43)). No significant differences in rest of polymorphisms or clinical or demographic variables were found. CONCLUSIONS: Polymorphic variations of CALCA and TRPV1 genes might play a role as prognostic markers of efficacy of OnabotulinumtoxinA in chronic migraine female patients in our population.

Resultados de la inmnoadsorción en el trasplante ABOi y el rechazo humoral en una unidad de hemodiáisis hospitalaria / Results of immunoadsorption in the ABOi kidney transplantation and humoral rejection in a hospital hemodialysis unit

Introducción: El tratamiento con inmunoadsorción no selectiva fue introducido en nuestra unidad de hemodiálisis hospitalaria con el objetivo de permitir la desensibilización previa a un trasplante renal con incompatibilidad de grupo sanguíneo y el tratamiento del rechazo mediado por anticuerpos. Objetivo: Analizar los resultados de la técnica de inmunoadsorción no selectiva, en una unidad de hemodiálisis hospitalaria. Material y Método: Estudio retrospectivo, descriptivo, de los primeros 18 pacientes tratados en nuestro centro con inmunoadsorción no selectiva (años 2012-2017) en las indicaciones de acondicionamiento del trasplante ABOi y tratamiento del rechazo humoral. Resultados: Durante un periodo de 5 años se analizaron un total de 128 sesiones de inmunoadsorción no selectiva. El 38,9% (n=7) de los casos para desensibilización previa al trasplante renal con incompatibilidad de grupo sanguíneo y el 61,1% (n=11) restante para el tratamiento del rechazo mediado por anticuerpos. En el primer caso, realizaron una media de 8±0,6 sesiones de inmunoadsorción previas al trasplante renal y el 57,1% se complementaron 2 sesiones posteriores. El tratamiento concomitante fue el protocolizado con Rituximab e inmunoglobulinas, requiriendo el 57,1% la realización de recambios plasmáticos. En el segundo caso, realizaron una media de 5,9±2 sesiones de inmunoadsorción. El tratamiento concomitante fue el mismo y el 27,3% realizaron recambios plasmáticos. Conclusiones: El trasplante renal de donante vivo ABOi tras la desensibilización fue posible en el 100% de los pacientes. El 72,7% de los pacientes tratados para el rechazo mediado por anticuerpos mantienen actualmente la funcionalidad del injerto

Introduction: The non-selective immunoadsorption treatment was introduced in our hospital hemodialysis unit with the aim of allowing desensitization prior to a kidney transplant with blood group incompatibility and the treatment of antibody-mediated rejection. Aim: To analyze the results of the non-selective immunoadsorption technique in a hospital hemodialysis unit. Material and methods: Retrospective descriptive study of the first 18 patients treated in our center with non-selective immunoadsorption (years 2012-2017) in the indications for ABOi transplant conditioning and treatment of humoral rejection. Results: During a period of 5 years, 128 non-selective immunoadsorption sessions were analyzed. 38.9% (n= 7) of cases for desensitization prior to renal transplantation with incompatibility of blood group and 61.1% (n=11) remaining for the treatment of antibody-mediated rejection. In the first case, an average of 8±0.6 sessions of immunoadsorption prior to kidney transplantation were performed and 57.1% were complemented by 2 subsequent sessions. The concomitant treatment was protocolled with rituximab and immunoglobulins, 57.1% requiring plasma exchanges. In the second case, an average of 5.9±2 immunoadsorption sessions were carried out. The concomitant treatment was the same and 27.3% performed plasma exchanges. Conclusions: Kidney transplantation from ABOi living donor after desensitization was possible in 100% of patients. 72.7% of patients treated for antibody-mediated rejection currently maintain graft functionality

The high-mobility group I-Y transcription factor is involved in cerebral ischemia and modulates the expression of angiogenic proteins.

The present study aims to identify transcription factors (TFs) contributing to angiogenesis, a mechanism involved in giving plasticity to the brain, as potential therapeutic targets after cerebral ischemia. The promoter sequences from candidate genes involved in angiogenesis were submitted to a comparative analysis by bioinformatics software. High-mobility group I-Y protein (HMGIY) TF characterization in a rat permanent focal cerebral ischemia model was performed by quantitative real time polymerase chain reaction and Western blot for the TF expression profile study. The TF functional study was carried out using a TF-TF interaction array and gene silencing by siRNA in rat brain microvascular endothelial cells. The results showed that the promoters shared a common TF binding site for HMGIY. The expression profile analysis in ischemic rat brain showed an increase in HMGIY mRNA in the acute phase and a progressive overexpression of protein over time post-ischemia. The interaction array analysis revealed that ischemia promotes the interaction of HMGIY with TFs involved in different cerebral plasticity processes. In vitro knockdown studies showed that angiopoietin 1 and vascular endothelial growth factor expression is controlled by HMGIY and that this TF is involved in cell survival in brain endothelial cells. These findings suggest that HMGIY is a potential therapeutic target that could promote brain repair functions after stroke.

Characterization of Gcf2/Lrrfip1 in experimental cerebral ischemia and its role as a modulator of Akt, mTOR and ß-catenin signaling pathways.

Leucine-rich repeat in Flightless-1 interaction protein 1 (Lrrfip1) is an up-regulated protein after cerebral ischemia whose precise role in the brain both in healthy and ischemic conditions is unclear. Different Lrrfip1 isoforms with distinct roles have been reported in human and mouse species. The present study aimed to analyze the Lrrfip1 transcriptional variants expressed in rat cortex, to characterize their expression patterns and subcellular location after ischemia, and to define their putative role in the brain. Five transcripts were identified and three of them (Lrrfip1, CRA_g and CRA_a' (Fli-I leucine-rich repeat associated protein 1 - Flap-1)) were analyzed by quantitative real-time polymerase chain reaction (qPCR). All the transcripts were up-regulated and showed differential expression patterns after in vivo and in vitro ischemia models. The main isoform, Lrrfip1, was found to be up-regulated from the acute to the late phases of ischemia in the cytoplasm of neurons and astrocytes of the peri-infarct area. This study demonstrates that Lrrfip1 activates ß-catenin, Akt, and mammalian target of rapamycin (mTOR) proteins in astrocytes and positively regulates the expression of the excitatory amino acid transporter subtype 2 (GLT-1). Our findings point to Lrrfip1 as a key brain protein that regulates pro-survival pathways and proteins and encourages further studies to elucidate its role in cerebral ischemia as a potential target to prevent brain damage and promote functional recovery after stroke.

Imbalance of neurotrophin receptor isoforms TrkB-FL/TrkB-T1 induces neuronal death in excitotoxicity.

A better understanding of the mechanisms underlying neuronal death in cerebral ischemia is required for the development of stroke therapies. Here we analyze the contribution of the tropomyosin-related kinase B (TrkB) neurotrophin receptor to excitotoxicity, a primary pathological mechanism in ischemia, which is induced by overstimulation of glutamate receptors of the N-methyl-D-aspartate type. We demonstrate a significant modification of TrkB expression that is strongly associated with neurodegeneration in models of ischemia and in vitro excitotoxicity. Two mechanisms cooperate for TrkB dysregulation: (1) calpain-processing of full-length TrkB (TrkB-FL), high-affinity receptor for brain-derived neurotrophic factor, which produces a truncated protein lacking the tyrosine-kinase domain and strikingly similar to the inactive TrkB-T1 isoform and (2) reverse regulation of the mRNA of these isoforms. Collectively, excitotoxicity results in a decrease of TrkB-FL, the production of truncated TrkB-FL and the upregulation of TrkB-T1. A similar neuro-specific increase of the TrkB-T1 isoform is also observed in stroke patients. A lentivirus designed for both neuro-specific TrkB-T1 interference and increased TrkB-FL expression allows recovery of the TrkB-FL/TrkB-T1 balance and protects neurons from excitotoxic death. These data implicate a combination of TrkB-FL downregulation and TrkB-T1 upregulation as significant causes of neuronal death in excitotoxicity, and reveal novel targets for the design of stroke therapies.

Tests neurológicos para la evaluación del pronóstico funcional en modelos de ictus isquémico en roedores / Neurological tests for functional outcome assessment in rodent models of ischaemic stroke

Un aspecto crítico en todos los modelos experimentales de patologías del sistema nervioso es la evaluación del pronóstico neurológico final. En el caso de una lesión cerebral isquémica focal, además de la determinación del tamaño de la lesión, una valiosa herramienta es la evaluación del déficit funcional final. Ello se debe al hecho de que el daño isquémico produce diferentes grados de deterioro sensoriomotor y cognitivo, que pueden proporcionar información sobre la ubicación y el tamaño de la lesión y sobre la eficacia de los tratamientos neuroprotectores después del daño agudo. Además, la magnitud de estas alteraciones también puede ser útil para predecir el resultado final y para evaluar terapias reparadoras a largo plazo. Con este fin se ha desarrollado una amplia gama de tests que permite la cuantificación de todos estos síntomas neurológicos. Esta revisión tiene como intención recopilar los tests de comportamiento más útiles diseñados para evaluar los síntomas neurológicos en los estudios de isquemia cerebral focal experimental en roedores inducida por oclusión de la arteria cerebral media, el modelo más utilizado para el estudio del ictus isquémico (AU)

A critical aspect in all models is the assessment of the final outcome of the modelling procedure. In the case of a focal ischaemic brain injury, apart from the determination of the size of the lesion, another valuable tool is the evaluation of the final functional deficit. Indeed, ischaemic damage leads to the appearance of different degrees of sensoriomotor and cognitive impairments, which may yield useful information on location and size of the lesion and on the efficacy of neuroprotective treatments after the acute injury. In addition, the magnitude of these impairments may also be useful to predict final outcome and to evaluate neuro-restorative therapies in a long-term scenario. To this aim, a wide range of tests has been developed which allow the quantification of all these neurological symptoms. This review intends to compile the most useful behavioural tests designed to assess neurological symptoms in studies of focal experimental cerebral ischemia in rodents induced by middle cerebral artery occlusion, the most commonly used model of ischaemic stroke (AU)

Longitudinal studies of ischemic penumbra by using 18F-FDG PET and MRI techniques in permanent and transient focal cerebral ischemia in rats.

At present, the goal of stroke research is the identification of a potential recoverable tissue surrounding the ischemic core, suggested as ischemic penumbra, with the aim of applying a treatment that attenuates the growth of this area. Our purpose was to determine whether a combination of imaging techniques, including (18)F-FDG PET and MRI could identify the penumbra area. Longitudinal studies of (18)F-FDG PET and MRI were performed in rats 3 h, 24 h and 48 h after the onset of ischemia. A transient and a permanent model of focal cerebral ischemia were performed. Regions of interest were located, covering the ischemic core, the border that progresses to infarction (recruited tissue), and the border that recovers (recoverable tissue) with early reperfusion. Analyses show that permanent ischemia produces severe damage, whereas the transient ischemia model does not produce clear damage in ADC maps at the earliest time studied. The only significant differences between values for recoverable tissue, (18)F-FDG (84±2%), ADC (108±5%) and PWI (70±8%), and recruited tissue, (18)F-FDG (77±3%), ADC (109±4%) and PWI (77±4%), are shown in (18)F-FDG ratios. We also show that recoverable tissue values are different from those in non-infarcted tissue. The combination of (18)F-FDG PET, ADC and PWI MRI is useful for identification of ischemic penumbra, with (18)F-FDG PET being the most sensitive approach to its study at early times after stroke, when a clear DWI deficit is not observed.

Lack of adrenomedullin, but not complement factor H, results in larger infarct size and more extensive brain damage in a focal ischemia model.

Adrenomedullin (AM) and its binding protein, complement factor H (FH), are expressed throughout the brain. In this study we used a brain-specific conditional knockout for AM and a complete knockout for FH to investigate the effect of these molecules on the pathophysiology of stroke. Following 48 h of middle cerebral artery permanent occlusion, there was a statistically significant infarct size increase in animals lacking AM when compared to their wild type littermates. In contrast, lack of FH did not affect infarct volume. To investigate some of the mechanisms by which lack of AM may augment brain damage, markers of nitrosative stress, apoptosis, and autophagy were studied at the mRNA and protein levels. There was a significant increase of inducible nitric oxide synthase (iNOS), matrix metalloproteinase-9 (MMP9), fractin, and Beclin-1 in the peri-infarct area of AM-deficient mice when compared to their wild type counterparts and to contralateral and sham-operated controls. These data suggest that AM exerts a neuroprotective action in the brain and that this protection may be mediated by regulation of iNOS, matrix metalloproteases, and inflammatory mediators. In the future, substances that increase AM actions in the central nervous system may be used as potential neuroprotective agents in stroke.

Allosteric modulation of alpha 7 nicotinic receptors selectively depolarizes hippocampal interneurons, enhancing spontaneous GABAergic transmission.

The role of postsynaptic nicotinic receptors for acetylcholine (nAChRs) in mediating fast neurotransmission processes in the CNS is controversial. Here we have studied the modulation of synaptic transmission by an agonist (choline) and an allosteric modulator (5-OH-indole) of alpha7 nAChRs in rat hippocampal neuronal cultures. Choline evoked a fast inactivating inward current, causing neuron depolarization and action potential discharge, thereby enhancing the spontaneous postsynaptic current activity (sPSCs). This effect was markedly enhanced when both choline and 5-OH-indole were applied together and was blocked by the selective alpha7 nAChR antagonist methyllycaconitine. This choline action was suppressed by the GABA(A) receptor antagonist bicuculline, while the glutamatergic receptor antagonist kynurenic acid had no effect. Frequency, but not amplitude or area, of both excitatory and inhibitory miniature postsynaptic currents (mEPSCs and mIPSCs) were drastically reduced when Ca(2+) influx was blocked by Cd(2+). Additionally, nAChR activation did not modify the mIPSCs. These data suggest that Ca(2+) influx through the highly Ca(2+)-permeablealpha7 nAChRs was insufficient to directly activate neurotransmitter release, suggesting that a tight colocalization of this receptor with secretory hot spots is unlikely. In a few cases, the activation of alpha7 AChRs led to a suppression of spontaneous synaptic transmission. This effect may be related to the potentiation of GABAergic interneurons that inhibit the spontaneous activity of neurons making synapses with the cell under study. We suggest that GABA release is modulated by alpha7 nAChRs. Thus, selective allosteric modulators of alpha7 nAChRs could have potential therapeutic applications in brain disorders such as epilepsy and schizophrenia and in alterations of cognition and sensory processing.

Excitotoxicity and focal cerebral ischemia induce truncation of the NR2A and NR2B subunits of the NMDA receptor and cleavage of the scaffolding protein PSD-95.

The N-methyl-D-aspartate receptor (NMDAR) is central to physiological and pathological functioning of neurons. Although promising results are beginning to be obtained in the treatment of dementias, clinical trials with NMDAR antagonists for stroke, trauma and neurodegenerative disorders, such as Hungtinton's disease, have failed before. In order to design effective therapies to prevent excitotoxic neuronal death, it is critical to characterize the consequences of excessive NMDAR activation on its expression and function. Previous data have reported partial downregulation of the NR1 and NR2B receptor subunits in response to excitotoxicity and cerebral ischemia. However, the effect of NMDAR overactivation on NR2A, a subunit fundamental to synaptic transmission and neuronal survival, is still elusive. In this study, we report the rapid and extensive proteolytic processing of NR2A, together with the scaffolding protein postsynaptic density-95 (PSD-95), induced by excitotoxic stimulation of cortical neurons in vitro and by transient focal cerebral ischemia. Processing of the C terminus of NR2A is irreversibly induced by brief agonist exposure of NR2B-containing receptors, and requires calcium influx and the activity of calpain, also responsible for PSD-95 cleavage. The outcome is a truncated NR2A subunit that is stable and capable to interact with NR1 at the surface of neurons, but lacking the structural domains required for association with scaffolding, downstream signaling and cytoskeletal proteins. Therefore, a rapid and significant uncoupling of synaptic NMDARs from downstream survival pathways is expected to occur during ischemia. This novel mechanism induced by excitotoxicity helps to explain the failure of most therapies based on NMDAR antagonists.

Neuroprotection afforded by nicotine against oxygen and glucose deprivation in hippocampal slices is lost in alpha7 nicotinic receptor knockout mice.

Although alpha7-receptors are considered the main target for neuroprotection, other receptor subtypes (alpha4beta2 or alpha3beta4) have also been implicated. Hence, we have used alpha7-transgenic mice, to study the hypothesis that alpha7-receptors play a dominant role in mediating neuroprotection in an in vitro model of ischemia. We have used rat and mouse hippocampal slices to establish the model of nicotinic neuroprotection against oxygen and glucose deprivation (OGD). Neuronal damage caused by OGD during 1 h plus 3 h re-oxygenation, was quantified by measuring lactate dehydrogenase (LDH) release from hippocampal slices. In rat hippocampal slices, OGD increased over twofold basal LDH release. Such increase was reduced when treated with 10-100 microM nicotine; maximal protection afforded by nicotine amounted to 46%. This neuroprotection was antagonized by the non-selective nicotinic receptor for acetylcholine (nAChR) blocker mecamylamine (10 microM). In hippocampal slices from wild-type control mice, nicotine (100 microM) decreased by 54.4% LDH release evoked by OGD plus re-oxygenation. In contrast, nicotine failed to exert neuroprotection in alpha7 knockout mice. This finding reinforces the view that the hippocampal neuroprotective effects of nicotine are predominantly linked to alpha7 receptors.

Relationship of water transport to anatomical features in the mangrove Laguncularia racemosa grown under contrasting salinities.

The purpose of this study was to investigate the xylem anatomy and hydraulic characteristics of the mangrove Laguncularia racemosa grown under contrasting salinities. The study addressed the hypothesis that, at high salinity, water transport capacity may decrease in association with higher water use efficiency. Plants were grown in media to which 0, 15 and 30 NaCl was added. Vessel density and diameter were determined in transverse sections of stem and midrib leaves in terminal shoots, and hydraulic parameters were measured. In stems, the vessel density increased with salinity, while the anatomical diameter (d(a)) and hydraulic diameter (d(h)) declined; in leaves, these parameters remained unchanged with salinity. Huber value and hydraulic and specific conductivities decreased with salinity. Leaf blade resistance increased with salinity and represented the largest fraction of twig resistance. Xylem anatomy and leaf tissue of L. racemosa appeared to be modulated by salinity, which led to a coordinated decline in hydraulic properties as salinity increased. Therefore, these structural changes would reflect functional water use characteristics of leaves under salinity.

Differential leaf gas exchange responses to salinity and drought in the mangrove tree Avicecennia germinans (Avicenniaceae)

Leaf gas exchange was assessed in Avicennia germinans L. grown under different NaCl concentrations (0-40 per thousand), after salt-relief, and then during drought. Stomatal conductance (gs) and net photosynthetic rate (Pn) decreased with increasing NaCl concentration, and intrinsic water use efficiency (Pn / gs) increased. Under desalinization Pn / gs declined. Thus, gs did not change in plants grown at low NaCl concentration (10 per thousand), but increased up to 30-32% at higher NaCl concentration (20-40 per thousand). However, Pn was only slightly enhanced (10-15%). Under drought, Pn decreased by as much as 46% in plants grown at low NaCl concentration (10 per thousand) and by 22% at high NaCl concentration (40 per thousand). Thus, Pn / gs decreased and water use efficiency was lower during drought compared to estimates prior to salt-relief.

Se estudió el intercambio de gases en las hojas de Avicennia germinans L. en varias concentraciones de NaCl (0-40‰), después de la desalinización y durante la desecación. La conductancia de los estomas (gs) y la tasa de fotosíntesis (Pn) decrecieron con el incremento en la concentración de NaCl, y se incrementó la eficiencia en el uso intrínseco de agua (Pn / gs). Bajo desalinización Pn / gs declinó. Así, gs no cambia en el crecimiento de las plantas a bajas concentraciones de NaCl (10‰), pero se incrementó hasta 30-32% a las concentraciones de NaCl más altas (20 - 40‰). Sin embargo, Pn aumentó ligeramente (10-15%). En desecación Pn fue reducido hasta un 46% a bajas concentaciones (10‰) de NaCl, y a un 22% a altas concentraciones (40‰) de NaCl. Así, Pn / gs decrecieron y la eficiencia en el uso de agua fue menor durante desecación en comparación con los evalolres stimados previos a la desalinización.

Differential leaf gas exchange responses to salinity and drought in the mangrove tree Avicecennia germinans (Avicenniaceae).

Leaf gas exchange was assessed in Avicennia germinans L. grown under different NaCl concentrations (0-40 per thousand), after salt-relief, and then during drought. Stomatal conductance (gs) and net photosynthetic rate (Pn) decreased with increasing NaCl concentration, and intrinsic water use efficiency (Pn / gs) increased. Under desalinization Pn / gs declined. Thus, gs did not change in plants grown at low NaCl concentration (10 per thousand), but increased up to 30-32% at higher NaCl concentration (20-40 per thousand). However, Pn was only slightly enhanced (10-15%). Under drought, Pn decreased by as much as 46% in plants grown at low NaCl concentration (10 per thousand) and by 22% at high NaCl concentration (40 per thousand). Thus, Pn / gs decreased and water use efficiency was lower during drought compared to estimates prior to salt-relief.

Combined nimodipine and citicoline reduce infarct size, attenuate apoptosis and increase bcl-2 expression after focal cerebral ischemia.

Cerebral ischemia triggers a multitude of pathophysiological and biochemical events that separately affect the evolution of focal ischemia and, therefore, stroke treatment should logically employ all known neuroprotective agents. We hypothesized that a treatment combining nimodipine and citicoline might have a potential neuroprotective effect. To assess this idea, Sprague-Dawley rats underwent transient bilateral common carotid artery ligation with simultaneous middle cerebral artery occlusion for 60 min. Four treatment groups were established. Animals received either: a) saline (control group); b) intracarotid nimodipine infusion during 30 min in the ischemia-reperfusion (nimodipine group); c) i.p. postischemic citicoline injections once daily for 7 days (citicoline group); or d) intracarotid nimodipine bolus during ischemia-reperfusion plus i.p. postichemic citicoline injections (combination group). They were killed after either 7 or 3 days after reperfusion. In the first case, the volume of the infarcted tissue was studied by a stereological procedure and in the second case, in situ end-labeling of nuclear DNA fragmentation (TUNEL) and Bcl-2 expression were employed to determine the level of apoptosis. The infarct volume was significantly reduced in both the nimodipine and the citicoline treatment groups after 7 days of reperfusion; combination of both drugs produced an additive effect. After 3 days of reperfusion, the number of Bcl-2-positive neurons was significantly increased while that of TUNEL-positive cells significantly decreased at the infarct border in the combined-treatment animals. Our findings demonstrate a neuroprotective effect from an acute single dose of nimodipine during ischemia-reperfusion and prolonged post-ischemic treatment with citicoline in a model of focal cerebral ischemia. These results suggest that a possible mechanism of neuroprotective action would be mediated by increased Bcl-2 expression and decreased apoptosis within the boundary zone of the infarct together with neutralization of the ischemia-reperfusion injury.

Adjustments in leaf water relations of mangrove (Avicennia germinans) seedlings grown in a salinity gradient.

We used pressure-volume analysis and dewpoint hygrometry to determine leaf water relation parameters of mangrove (Avicennia germinans L.) seedlings grown at salinities of 0, 8, 20 and 32 per thousand. Seedlings responded to an increase in salinity from 0 to 32 per thousand by an increase in leaf succulence as reflected in an increase in leaf water content per unit area from 300 to 360 g m(-2). Additionally, osmotic potential at full turgor decreased from -2.3 to -3.5 MPa and osmotic potential at zero turgor decreased from -2.7 to -4.3 MPa. Cell elasticity decreased as salinity increased from 0 to 32 per thousand, as indicated by a progressive increase in volumetric modulus of elasticity from 19 to 27 MPa. Increased leaf succulence enabled leaves to sequester large amounts of solutes without adversely increasing cell osmotic pressure. On the other hand, osmotic adjustment facilitated turgor maintenance as water potential diminished. Salinity-induced decreases in tissue elasticity generated greater water potential differences between leaves and soil under saline conditions than under non-saline conditions.

Salinity effects on the leaf water relations components and ion accumulation patterns in Avicennia germinans (L.) L. seedlings.

Physiological traits involved in leaf water relations were evaluated in Avicennia germinans (L.) L. seedlings growing at different salinities in the field. Analysis of pressure-volume (P-V) curves and sap osmometry were combined to evaluate osmotic adjustment and cell elasticity, and the contribution of accumulated inorganic ions to osmotic potential was estimated. Seedlings growing in soils with interstitial water salinity above that of normal sea water showed a modification of the relationship between water potential and relative water content. Thus, their leaf osmotic potential at maximum turgor (Ψπ(max)) and at zero turgor (Ψπ(0)) was 1.41 and 1.82 MPa lower respectively, than that of the seedlings from the low salinity site. Volumetric moduli of elasticity () were between 17 and 23 MPa. Thus, ɛ was about 6 MPa lower in high-salinity plants indicating that their cells were slightly more elastic. Ionic concentration analysis showed that Σ [anions] and Σ [cations] were higher in the high-salinity site (22-35%) while the water content per unit dry mass was only 12-17% lower. Reduction in water content was insufficient to explain the increase in ion concentration. Ion concentration explained 73 and 66% of the osmotic potential estimated by P-V curves for leaves from low- and high-salinity sites, respectively. In conclusion, this study provided evidence that leaves of A. germinans seedlings adapt to hypersaline soils by increasing solute concentration by 52% and cell elasticity by 26%. Both processes allow leaf water uptake and turgor maintenance over a large range of soil water potential.

[The food habits and energy and nutrient intake in overweight adolescents compared to those with normal weight]. / Hábitos alimentarios e ingesta de energía y nutrientes en adolescentes con sobrepeso en comparación con los de peso normal.

OBJECTIVE: The objective of this study was to investigate the differences between the foods, energy and nutrient intakes of normal weight and overweight/obese adolescents. MATERIAL AND METHODS: To this end, a survey was made of the food, energy and nutrient intake of 60 adolescents. The subjects kept a 5-day dietary record, including one Sunday. Adolescents were divided into two study groups:overweight and obese subjects (S; with a body mass index-BMI > or = 23 Kg/m2, 75th percentile) and subjects of normal weight (PN; BMI < 23 Kg/m2). RESULTS: We found no differences in the energy intake between obese and normal adolescents. Imbalances in the contribution of macronutrients to the total energy intake appear greater in overweight/obese adolescents with a greater proportion of their energy from fats and a lower percentage of their energy from carbohydrates. In addition, S subjects take-in significantly larger amounts of cholesterol. The situation was worse in S women who took 50% of their calories derived from fat, 21.9% from proteins and only 27.5% of their calories were derived from carbohydrates. CONCLUSIONS: We conclude that the most significant finding of this survey is that the diet composition, rather than energy consumption, was the main factor responsible for obesity in both young men and women. Our results suggest that a diet higher in fat and lower in carbohydrates, independent of total energy intake, may contribute to obesity in adolescents.