Changes in Calcium-Binding Protein Expression in Human Cortical Contusion Tissue

Traumatic brain injury (TBI) produces several cellular changes, such as gliosis, axonal and dendritic plasticity, and inhibition-excitation imbalance, as well as cell death, which can initiate epileptogenesis. It has been demonstrated that dysfunction of the inhibitory components of the cerebral cortex after injury may cause status epilepticus in experimental models; we proposed to analyze the response of cortical interneurons and astrocytes after TBI in humans. Twelve contusion samples were evaluated, identifying the expression of glial fibrillary acidic protein (GFAP) and calcium-binding proteins (CaBPs). The study was made in sectors with and without preserved cytoarchitecture evaluated with NeuN immunoreactivity (IR). In sectors with total loss of NeuN-IR the results showed a remarkable loss of CaBP-IR both in neuropil and somata. In sectors with conserved cytoarchitecture less drastic changes in CaBP-IR were detected. These changes include a decrease in the amount of parvalbumin (PV-IR) neurons in layer II, an increase of calbindin (CB-IR) neurons in layers III and V, and an increase in calretinin (CR-IR) neurons in layer II. We also observed glial fibrillary acidic protein immunoreactivity (GFAP-IR) in the white matter, in the gray-white matter transition, and around the sectors with NeuN-IR total loss. These findings may reflect dynamic activity as a consequence of the lesion that is associated with changes in the excitatory circuits of neighboring hyperactivated glutamatergic neurons, possibly due to the primary impact, or secondary events such as hypoxia-ischemia. Temporal evolution of these changes may be the substrate linking severe cortical contusion and the resulting epileptogenic activity observed in some patients.

Ontogenetic changes in the retinal photoreceptor mosaic in a fish, the black bream, Acanthopagrus butcheri

The morphological development of the photoreceptor mosaic was followed by light and electron microscopy in a specific region of dorsal retina of the black bream, Acanthopagrus butcheri (Sparidae, Teleostei), from hatching to eight weeks of age. The retina was differentiated when the larvae reached a total length of 3 mm (3-5 days posthatch). Single cones, arranged in tightly packed rows, were the only morphologically distinct type of photoreceptor present until the larvae were 6 mm (day 15) in standard length (SL). At this time, the rad nuclei had become differentiated and the ellipsoids of selected cones began to form subsurface cisternae along neighbouring cone membranes. In this way, double, triple, quadruple, and occasionally photoreceptor chains of up to 10 cones were formed. At 8 mm SL, there was little apparent order in the photoreceptor mosaic. However, concomitant with subsequent growth, quadruple and other multiple cone receptors disappeared, with the exception of the triple cones, which gradually reduced in both number and retinal coverage to be restricted to central retina by 15 mm SL (days 40-55). Following this stage, the arrangement of double and single cones peripheral to the region of triple cones in dorsal retina was transformed into the adult pattern of a regular mosaic of four double cones surrounding a single cone. These results demonstrate that an established photoreceptor mosaic of rows of single cones can be reorganised to form a regular square mosaic composed of single and double cones. J. Comp. Neural. 412:203-217, 1999. (C) 1999 Wiley-Liss, Inc.

Spatial and temporal variation in distribution of mangroves in Moreton Bay, subtropical Australia: a comparison of pattern metrics and change detection analyses based on aerial photographs

An assessment of the changes in the distribution and extent of mangroves within Moreton Bay, southeast Queensland, Australia, was carried out. Two assessment methods were evaluated: spatial and temporal pattern metrics analysis, and change detection analysis. Currently, about 15,000 ha of mangroves are present in Moreton Bay. These mangroves are important ecosystems, but are subject to disturbance from a number of sources. Over the past 25 years, there has been a loss of more than 3800 ha, as a result of natural losses and mangrove clearing (e.g. for urban and industrial development, agriculture and aquaculture). However, areas of new mangroves have become established over the same time period, offsetting these losses to create a net loss of about 200 ha. These new mangroves have mainly appeared in the southern bay region and the bay islands, particularly on the landward edge of existing mangroves. In addition, spatial patterns and species composition of mangrove patches have changed. The pattern metrics analysis provided an overview of mangrove distribution and change in the form of single metric values, while the change detection analysis gave a more detailed and spatially explicit description of change. An analysis of the effects of spatial scales on the pattern metrics indicated that they were relatively insensitive to scale at spatial resolutions less than 50 m, but that most metrics became sensitive at coarser resolutions, a finding which has implications for mapping of mangroves based on remotely sensed data. (C) 2003 Elsevier Science B.V. All rights reserved.

Age-related gray matter volume changes in the brain during non-elderly adulthood

Previous magnetic resonance imaging (MRI) studies described consistent age-related gray matter (GM) reductions in the fronto-parietal neocortex, insula and cerebellum in elderly subjects, but not as frequently in limbic/paralimbic structures. However, it is unclear whether such features are already present during earlier stages of adulthood, and if age-related GM changes may follow non-linear patterns at such age range. This voxel-based morphometry study investigated the relationship between GM volumes and age specifically during non-elderly life (18-50 years) in 89 healthy individuals (48 males and 41 females). Voxelwise analyses showed significant (p < 0.05, corrected) negative correlations in the right prefrontal cortex and left cerebellum, and positive correlations (indicating lack of GM loss) in the medial temporal region, cingulate gyrus, insula and temporal neocortex. Analyses using ROI masks showed that age-related dorsolateral prefrontal volume decrements followed non-linear patterns, and were less prominent in females compared to males at this age range. These findings further support for the notion of a heterogeneous and asynchronous pattern of age-related brain morphometric changes, with region-specific non-linear features. (C) 2009 Elsevier Inc. All rights reserved.

The renin-angiotensin system is upregulated in the cortex and hippocampus of patients with temporal lobe epilepsy related to mesial temporal sclerosis

Purpose: As reported by several authors, angiotensin II (AngII) is a proinflammatory molecule that stimulates the release of inflammatory cytokines and activates nuclear factor kappa B (NF kappa B), being also associated with the increase of cellular oxidative stress. Its production depends on the activity of the angiotensin converting enzyme (ACE) that hydrolyzes the inactive precursor angiotensin I (AngI) into AngII. It has been suggested that AngII underlies the physiopathological mechanisms of several brain disorders such as stroke, bipolar disorder, schizophrenia, and disease. The aim of the present work was to localize and quantify AngII AT1 and AT2 receptors in the cortex and hippocampus of patients with temporal lobe epilepsy related to mesial temporal sclerosis (MTS) submitted to corticoamygdalohippocampectomy for seizure control. Method: Immunohistochemistry, Western blot, and real-time PCR techniques were employed to analyze the expression of these receptors. Results: The results showed an upregulation of AngII AT1 receptor as well as its messenger ribonucleic acid (mRNA) expression in the cortex and hippocampus of patients with MTS. In addition, an increased immunoexpression of AngII AT2 receptors was found only in the hippocampus of these patients with no changes in its mRNA levels. Discussion: These data show, for the first time, changes in components of renin-angiotensin system (RAS) that could be implicated in the physiopathology of MTS.

Mesial temporal lobe epilepsy: Clinical and neuropathologic findings of familial and sporadic forms

Purpose: To evaluate the clinical and hippocampal histological features of patients with mesial temporal lobe epilepsy (MTLE) in both familial (FMTLE) and sporadic (SMTLE) forms. Methods: Patients with FMTLE (n = 20) and SMTLE (n = 39) who underwent surgical treatment for refractory seizures were studied at the University of Sao Paulo School of Medicine at Ribeirao Preto. FMTLE was defined when at least two individuals in a family had clinical diagnosis of MTLE. Hippocampi from all patients were processed for Nissl/HE and Timm`s stainings. Both groups were compared for clinical variables, hippocampal cell densities, and intensity of supragranular mossy fiber staining. Results: There were no significant differences between FMTLE and SMTLE groups in the following: age at the surgery, age of first usual epileptic seizure, history of initial precipitating injury (IPI), age of IPI, latent period, ictal and interictal video-EEG patterns, presence of hippocampal atrophy and signal changes at MRI, and postoperative outcome. In addition, no differences were found in cell densities in hippocampal cornu ammonis subfields (CA1, CA2, CA3, CA4), fascia dentata, polymorphic region, subiculum, prosubiculum, and presubiculum. However, patients with SMTLE had greater intensity of mossy fiber Timm`s staining in the fascia dentata-inner molecular layer (p < 0.05). Discussion: Patients with intractable FMTLE present a clinical profile and most histological findings comparable to patients with SMTLE. Interestingly, mossy fiber sprouting was less pronounced in patients with FMTLE, suggesting that, when compared to SMTLE, patients with FMTLE respond differently to plastic changes plausibly induced by cell loss, neuronal deafferentation, or epileptic seizures.

Interlaminar differences in the pyramidal cell phenotype in cortical areas 7m and STP (the superior temporal polysensory area) of the macaque monkey

Pyramidal neurones were injected with Lucifer Yellow in slices cut tangential to the surface of area 7m and the superior temporal polysensory area (STP) of the macaque monkey. Comparison of the basal dendritic arbors of supra- and infragranular pyramidal neurones (n=139) that were injected in the same putative modules in the different cortical areas revealed variation in their structure. Moreover, there were relative differences in dendritic morphology of supra- and infragranular pyramidal neurones in the two cortical areas. Shell analyses revealed that layer III pyramidal neurones in area STP had considerably higher peak complexity (maximum number of dendritic intersections per Shell circle) than those in layer V, whereas peak complexities were similar for supra- and infragranular pyramidal neurones in area 7m. In both cortical areas, the basal dendritic trees of layer m pyramidal neurones were characterized by a higher spine density than those in layer V. Calculations of the total number of dendritic spines in the average basal dendritic arbor revealed that layer V pyramidal neurones in area 7m had twice as many spines as cells in layer III. (4535 and 2294, respectively). A similar calculation for neurones in area STP revealed that layer III pyramidal neurones had approximately the same number of spines as cells in layer V (3585 and 3850 spines, respectively). Relative differences in the branching patterns of, and the number of spines in, the basal dendritic arbors of supra- and infragranular pyramidal neurones in the different cortical areas may allow for integration of different numbers of inputs, and different degrees of dendritic processing. These results support the thesis that intra-areal circuitry differs in different cortical areas.

Valproic acid has temporal variability in urinary clearance of metabolites

The reasons for the intra- and interindividual variability in the clearance of valproic acid (VPA) have not been completely characterized. The aim of this study was to examine day-night changes in the clearance of 3-oxo-valproate (3-oxo-VPA), 4-hydroxy-valproate (4-OH-VPA), and valproic acid glucuronides under steady state. Six diurnally active healthy male volunteers ingested 200 mg sodium valproate 12 hourly, at 0800 and 2000, for 28 days. On the last study day, two sequential 12-h urine samples were collected commencing at 2000 the evening before. Plasma samples were obtained at the end of each collection. Following alkaline hydrolysis, urine was analyzed for concentrations of VPA, 3-oxo-VPA, and 4-OH-VPA. A separate aliquot was assayed for creatinine (CR). The plasma concentrations of VPA, 3-oxo-VPA, 2-en-VPA, and CR were determined. The analysis of VPA and its metabolites was performed by CC-MS. There was an increase in plasma 3-oxo-VPA concentration at 0800, sampling as compared to 2000 sampling (p < .05). The urinary excretion of 3-oxo-VPA and VPA glucuronides were decreased between 2000 and 0800, compared to between 0800, and 2000, by 30% and 50% respectively (p < .05). These results indicate a nocturnal decrease in renal clearance of 3-oxo-VPA rather than a decrease in the beta -oxidation of VPA at night. These differences were not explained by differences between the sampling periods in CR excretion. These results indicate the importance of collecting samples of 24-h duration when studying metabolic profiles of VPA.

Changes in muscle recruitment patterns during skill acquisition

The control of movement is predicated upon a system of constraints of musculoskeletal and neural origin. The focus of the present study was upon the manner in which such constraints are adapted or superseded during the acquisition of motor skill. Individuals participated in five experimental sessions, ill which they attempted to produce abduction-adduction movements of the index finger in time with an auditory metronome. During each trial, the metronome frequency was increased in eight steps from an individually determined base frequency. Electromyographic (EMC) activity was recorded from first dorsal interosseous (FDI), first volar interosseous (FVI), flexor digitorum superficialis (FDS), and extensor digitorum communis (EDC) muscles. The movements produced on the final day of acquisition more accurately matched the required profile, and exhibited greater spatial and temporal stability, than those generated during initial performance. Tn the early stages of skill acquisition, an alternating pattern of activation in FDI and FVI was maintained, even at the highest frequencies. Tn contrast, as the frequency of movement was increased, activity in FDS and EDC was either tonic or intermittent. As learning proceeded, alterations in recruitment patterns were expressed primarily in the extrinsic muscles (EDC and FDS). These changes took the form of increases in the postural role of these muscles, shifts to phasic patterns of activation, or selective disengagement of these muscles. These findings suggest that there is considerable flexibility in the composition of muscle synergies, which is exploited by individuals during the acquisition of coordination.

Therapeutic patellar taping changes the timing of vasti muscle activation in people with patellofemoral pain syndrome

Objective: To examine the effect of the application of tape over the patella on the onset of electromyographic (EMG) activity of vastus medialis obliquus (VMO) relative to vastus lateralis (VL) in participants with and without patellofemoral pain syndrome (PFPS). Design: Randomised within subject. Settings: University laboratory. Participants: Ten participants with PFPS and 12 asymptomatic controls. Interventions: Three experimental taping conditions: no tape, therapeutic tape, and placebo tape. Main Outcome Measures: Electromyographic onset of VMO and VL assessed during the concentric and eccentric phases of a stair stepping task. Results: When participants with PFPS completed the stair stepping task, the application of therapeutic patellar tape was found to alter the temporal characteristics of VMO and VL activation, whereas placebo tape had no effect. In contrast, there was no change in the EMG onset of VMO and VL with the application of placebo or therapeutic tape to the knee in the asymptomatic participants. Conclusions: These data support the use of patellar taping as an adjunct to rehabilitation in people with PFPS.

Acoustic analysis of speech through a hearing aid: perceptual effects of changes with two-channel compression

Compression amplification significantly alters the acoustic speech signal in comparison to linear amplification. The central hypothesis of the present study was that the compression settings of a two-channel aid that best preserved the acoustic properties of speech compared to linear amplification would yield the best perceptual results, and that the compression settings that most altered the acoustic properties of speech compared to linear would yield significantly poorer speech perception. On the basis of initial acoustic analysis of the test stimuli recorded through a hearing aid, two different compression amplification settings were chosen for the perceptual study. Participants were 74 adults with mild to moderate sensorineural hearing impairment. Overall, the speech perception results supported the hypothesis. A further aim of the study was to determine if variation in participants' speech perception with compression amplification (compared to linear amplification) could be explained by the individual characteristics of age, degree of loss, dynamic range, temporal resolution, and frequency selectivity; however, no significant relationships were found.

Reciprocal changes in forebrain contents of glycogen and of glutamate/glutamine during early memory consolidation in the day-old chick

Passive avoidance learning is with advantage studied in day-old chicks trained to distinguish between beads of two different colors, of which one at training was associated with aversive taste. During the first 30-min post-training, two periods of glutamate release occur in the forebrain. One period is immediately after the aversive experience, when glutamate release is confined to the left hemisphere. A second release, 30 min later, may be bilateral, perhaps with preponderance of the right hemisphere. The present study showed increased pool sizes of glutamate and glutamine, specifically in the left hemisphere, at the time when the first glutamate release occurs, indicating de novo synthesis of glutamate/glutamine from glucose or glycogen, which are the only possible substrates. Behavioral evidence that memory is extinguished by intracranial administration at this time of iodoacetate, an inhibitor of glycolysis and glycogenolysis, and that the extinction of memory is counteracted by injection of glutamine, supports this concept. A decrease in forebrain glycogen of similar magnitude and coinciding with the increase in glutamate and glutamine suggests that glycogen rather than glucose is the main source of newly synthesized glutamate/glutamine. The second activation of glutamatergic activity 30 min after training, when memory is consolidated into stable, long-term memory, is associated with a bilateral increase in pool size of glutamate/glutamine. No glycogenolysis was observed at this time, but again there is a temporal correlation with sensitivity to inhibition by iodoacetate and rescue by glutamine, indicating the importance of de novo synthesis of glutamate/glutamine from glucose or glycogen. (C) 2003 Elsevier B.V All rights reserved.

The pyramidal neuron in occipital, temporal and prefrontal cortex of the owl monkey (Aotus trivirgatus): regional specialization in cell structure

Recent studies have revealed marked regional variation in pyramidal cell morphology in primate cortex. In particular, pyramidal cells in human and macaque prefrontal cortex (PFC) are considerably more spinous than those in other cortical regions. PFC pyramidal cells in the New World marmoset monkey, however, are less spinous than those in man and macaques. Taken together, these data suggest that the pyramidal cell has become more branched and more spinous during the evolution of PFC in only some primate lineages. This specialization may be of fundamental importance in determining the cognitive styles of the different species. However, these data are preliminary, with only one New World and two Old World species having been studied. Moreover, the marmoset data were obtained from different cases. In the present study we investigated PFC pyramidal cells in another New World monkey, the owl monkey, to extend the basis for comparison. As in the New World marmoset monkey, prefrontal pyramidal cells in owl monkeys have relatively few spines. These species differences appear to reflect variation in the extent to which PFC circuitry has become specialized during evolution. Highly complex pyramidal cells in PFC appear not to have been a feature of a common prosimian ancestor, but have evolved with the dramatic expansion of PFC in some anthropoid lineages.

Variabilidade espacial e temporal de atributos químicos do solo em povoamento de eucalipto

Nos anos mais recentes, observa-se aumento na adoção das técnicas de silvicultura de precisão em florestas plantadas no Brasil. Os plantios de eucalipto ocorrem preferencialmente em áreas com baixa fertilidade de solo e consequentemente baixa produtividade. Logo, para otimizar ao máximo a produção, é necessário saber o quanto essa cultura pode produzir em cada local (sítio). Objetivou-se aplicar uma metodologia que utiliza técnicas de estatística, geoestatística e geoprocessamento, no mapeamento da variabilidade espacial e temporal de atributos químicos do solo cultivado com eucalipto, em área de 10,09 ha, situada no sul do estado do Espírito Santo. Os atributos químicos da fertilidade do solo estudados foram: fósforo (P), potássio (K), cálcio (Ca) e magnésio (Mg), no ano da implantação do povoamento do eucalipto, em 2008, e três anos após, em 2011. O solo foi amostrado em duas profundidades, 0-0,2 m e 0,2-0,4 m, nos 94 pontos de uma malha regular, com extensão de 33 x 33 m. Os dados foram analisados pela estatística descritiva e, em seguida, pela geoestatística, por meio do ajuste de semivariogramas. Diferentes métodos de interpolação foram testados para produzir mapas temáticos mais precisos e facilitar as operações algébricas utilizadas. Com o auxílio de índices quantitativos, realizou-se uma análise geral da fertilidade do solo, por meio da álgebra de mapas. A metodologia utilizada neste estudo possibilitou mapear a variabilidade espacial e temporal de atributos químicos do solo. A análise variográfica mostrou que todos os atributos estudados apresentaram-se estruturados espacialmente, exceto para o atributo P, no Ano Zero (camada 0-0,2 m) e no Ano Três (ambas as camadas). Os melhores métodos de interpolação para o mapeamento de cada atributo químico do solo foram identificados com a ajuda gráfica do Diagrama de Taylor. Mereceram destaque, os modelos esférico e exponencial nas interpolações para a maioria dos atributos químicos do solo avaliados. Apesar de a variação espacial e temporal dos atributos estudados apresentar-se, em média, com pequena variação negativa, a metodologia usada mostrou variações positivas na fertilidade do solo em várias partes da área de estudo. Além disso, os resultados demonstram que os efeitos observados são majoritariamente em função da cultura, uma vez que não foram coletadas amostras de solo em locais adubados. A produtividade do sítio florestal apresentou-se com tendências semelhantes às variações ocorridas na fertilidade do solo, exceto para o magnésio, que se mostrou com tendências espaciais para suporte de elevadas produtividades, de até 50 m3 ha-1 ano-1. Além de mostrar claramente as tendências observadas para as variações na fertilidade do solo, a metodologia utilizada confirma um caminho operacional acessível para empresas e produtores florestais para o manejo nutricional em florestas plantadas. O uso dos mapas facilita a mobilização de recursos para melhorar a aplicação de fertilizantes e corretivos necessários.

Temporal variation in reproductive phenology of Patella spp.: past and present.

World Congress of Malacology, Universidade dos Açores, Ponta Delgada, 21-28 de julho.