oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 1015 )

2018 ( 1520 )

2017 ( 1479 )

2016 ( 1994 )

Custom range...

Search Results: 1 - 10 of 814150 matches for " M.A.L.;Timo-Iaria "
All listed articles are free for downloading (OA Articles)
Page 1 /814150
Display every page Item
The brain decade in debate: VI. Sensory and motor maps: dynamics and plasticity
Das, A.;Franca, J.G.;Gattass, R.;Kaas, J.H.;Nicolelis, M.A.L.;Timo-Iaria, C.;Vargas, C.D.;Weinberger, N.M.;Volchan, E.;
Brazilian Journal of Medical and Biological Research , 2001, DOI: 10.1590/S0100-879X2001001200001
Abstract: this article is an edited transcription of a virtual symposium promoted by the brazilian society of neuroscience and behavior (sbnec). although the dynamics of sensory and motor representations have been one of the most studied features of the central nervous system, the actual mechanisms of brain plasticity that underlie the dynamic nature of sensory and motor maps are not entirely unraveled. our discussion began with the notion that the processing of sensory information depends on many different cortical areas. some of them are arranged topographically and others have non-topographic (analytical) properties. besides a sensory component, every cortical area has an efferent output that can be mapped and can influence motor behavior. although new behaviors might be related to modifications of the sensory or motor representations in a given cortical area, they can also be the result of the acquired ability to make new associations between specific sensory cues and certain movements, a type of learning known as conditioning motor learning. many types of learning are directly related to the emotional or cognitive context in which a new behavior is acquired. this has been demonstrated by paradigms in which the receptive field properties of cortical neurons are modified when an animal is engaged in a given discrimination task or when a triggering feature is paired with an aversive stimulus. the role of the cholinergic input from the nucleus basalis to the neocortex was also highlighted as one important component of the circuits responsible for the context-dependent changes that can be induced in cortical maps.
Absence-like seizures in adult rats following pilocarpine-induced status epilepticus early in life
Ferreira, B.L.C.;Valle, A.C.;Cavalheiro, E.A.;Timo-Iaria, C.;
Brazilian Journal of Medical and Biological Research , 2003, DOI: 10.1590/S0100-879X2003001200010
Abstract: administration of pilocarpine causes epilepsy in rats if status epilepticus (se) is induced at an early age. to determine in detail the electrophysiological patterns of the epileptogenic activity in these animals, 46 wistar rats, 7-17 days old, were subjected to se induced by pilocarpine and electro-oscillograms from the cortex, hippocampus, amygdala, thalamus and hypothalamus, as well as head, rostrum and vibrissa, eye, ear and forelimb movements, were recorded 120 days later. six control animals of the same age range did not show any signs of epilepsy. in all the rats subjected to se, iterative spike-wave complexes (8.1 ± 0.5 hz in frequency, 18.9 ± 9.1 s in duration) were recorded from the frontal cortex during absence fits. however, similar spike-wave discharges were always found also in the hippocampus and, less frequently, in the amygdala and in thalamic nuclei. repetitive or single spikes were also detected in these same central structures. clonic movements and single jerks were recorded from all the rats, either concomitantly with or independently of the spike-wave complexes and spikes. we conclude that rats made epileptic with pilocarpine develop absence seizures also occurring during paradoxical sleep, showing the characteristic spike-wave bursts in neocortical areas and also in the hippocampus. this is in contrast to the well-accepted statement that one of the main characteristics of absence-like fits in the rat is that spike-wave discharges are never recorded from the hippocampal fields.
Absence-like seizures in adult rats following pilocarpine-induced status epilepticus early in life
Ferreira B.L.C.,Valle A.C.,Cavalheiro E.A.,Timo-Iaria C.
Brazilian Journal of Medical and Biological Research , 2003,
Abstract: Administration of pilocarpine causes epilepsy in rats if status epilepticus (SE) is induced at an early age. To determine in detail the electrophysiological patterns of the epileptogenic activity in these animals, 46 Wistar rats, 7-17 days old, were subjected to SE induced by pilocarpine and electro-oscillograms from the cortex, hippocampus, amygdala, thalamus and hypothalamus, as well as head, rostrum and vibrissa, eye, ear and forelimb movements, were recorded 120 days later. Six control animals of the same age range did not show any signs of epilepsy. In all the rats subjected to SE, iterative spike-wave complexes (8.1 ± 0.5 Hz in frequency, 18.9 ± 9.1 s in duration) were recorded from the frontal cortex during absence fits. However, similar spike-wave discharges were always found also in the hippocampus and, less frequently, in the amygdala and in thalamic nuclei. Repetitive or single spikes were also detected in these same central structures. Clonic movements and single jerks were recorded from all the rats, either concomitantly with or independently of the spike-wave complexes and spikes. We conclude that rats made epileptic with pilocarpine develop absence seizures also occurring during paradoxical sleep, showing the characteristic spike-wave bursts in neocortical areas and also in the hippocampus. This is in contrast to the well-accepted statement that one of the main characteristics of absence-like fits in the rat is that spike-wave discharges are never recorded from the hippocampal fields.
Somatic Embryogenesis and Plant Regeneration from Immature Embryo Derived Callus of Inbred Maize (Zea mays L.)
A.M. Shohael,M.A.L. Akanda,S. Parvez,S. Mahfuja
Biotechnology , 2003,
Abstract: The present study was carried out to develop protocol in which plants could be regenerated with easy and in high numbers from tissue cultures of maize. The tissues of immature embryos were tested in three inbred lines (CML-161, CML-323, CML-327) MS and N6 were used. In N6 medium, the range of embryogenic calli formation was varied from 56.33-72.0%. The results indicated that the highest amount 72.0% was obtained when N6 was supplemented with L-proline 2.3 gm l-1, Casein Hydrolysate 200 mg l-1 and 2,4-D 1.0 mg l-1. Where as in MS medium the embryogenic calli formation was varied from 39.0-68.66%. In this case the highest amount (68.66) was obtained where MS was supplemented with L-Asparagine 150 mg l 1, Thiamin 50 mg l-1 and 2,4-D 1 mg l-1. Plants were regenerated successfully from embryogenic callus in hormone free MS medium. The results showed that MS (52.83-61.0%) medium was found better than N6 (35.66-42.49%). The mode of somatic embryogenesis was studied using histological technique.
An evoked potential mapping of transcallosal projections in the cat
Cukiert, A.;Timo-Iaria, C.;
Arquivos de Neuro-Psiquiatria , 1989, DOI: 10.1590/S0004-282X1989000100001
Abstract: in ten adult cats anesthetized with ketamine hydrochloride the neocortex was exposed and rectangular pulses (1msec, 0.5 hz and variable intensity) were applied to discrete points of one side and transcallosal evoked potentials were recorded from the other. the stimulation and recording positions were determined on a cartesian map of most of the exposable neocortical areas and the potentials were analysed as to their components, voltage and latency. passive spread and electrotonic potentials and the effects of increasing frequency were also analysed. the results showed large transcallosal potentials in some areas and an increase of potentials in the caudorostral direction, attaining the highest values in anteromedial areas of the suprasylvian gyrus. confirming anatomical studies, a few silent spots were found in the motor and somesthetic cortex and in restricted posterior regions of the visual cortex, where small or zero voltages occurred. while causing weak contralateral potentials, stimulation of some posterior sites provoked high voltage potentials in anterior regions of the side being stimulated and in the corresponding area of the opposite site. these posterior sites are. poorly interconnected by the corpus callosum. the l-shaped indirect connection described in this work may be involved in some types of epilepsy and may explain the effectiveness of partial callosotomy in their treatment.
Electrophysiological evidence for an L-shaped interhemispheric connection in the cat
Cukiert, A;Timo-Iaria, C.;
Arquivos de Neuro-Psiquiatria , 1989, DOI: 10.1590/S0004-282X1989000400001
Abstract: transcallosal potentials evoked by electrical stimulation with rectangular pulses of 1 ms, 5 c/s and variable intensity were recorded from the cortical surface in cats anesthetized with ketamine hydrochloride. sites of stimulation and recording were selected by means of a cartesian map of most of the neocortex. in addition to the well known transcallosal projection pattern it was found that stimulation of a restricted posterior area evokes low voltage potentials over the contralateral symmetric area while high voltage potentials are recorded from a few sites located at the ipsilateral anterior cortex and from the area symmetric as to the latter. this l-shaped transcallosal connection may be involved in complex cortical processes and is compatible with effective results of partial anterior callosotomies in patients with multifocal epilepsy and frontal bisynchronism.
The leaves of green plants as well as a cyanobacterium, a red alga, and fungi contain insulin-like antigens
Silva L.B.,Santos S.S.S.,Azevedo C.R.,Cruz M.A.L.
Brazilian Journal of Medical and Biological Research , 2002,
Abstract: We report the detection of insulin-like antigens in a large range of species utilizing a modified ELISA plate assay and Western blotting. We tested the leaves or aerial parts of species of Rhodophyta (red alga), Bryophyta (mosses), Psilophyta (whisk ferns), Lycopodophyta (club mosses), Sphenopsida (horsetails), gymnosperms, and angiosperms, including monocots and dicots. We also studied species of fungi and a cyanobacterium, Spirulina maxima. The wide distribution of insulin-like antigens, which in some cases present the same electrophoretic mobility as bovine insulin, together with results recently published by us on the amino acid sequence of an insulin isolated from the seed coat of jack bean (Canavalia ensiformis) and from the developing fruits of cowpea (Vigna unguiculata), suggests that pathways depending on this hormone have been conserved through evolution.
Efeito do ultra-som terapêutico em tendinite experimental de eqüinos: estudo clínico, ultra-sonográfico e histopatológico de dois protocolos
Fernandes, M.A.L.;Alves, G.E.S.;Souza, J.C.A.;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2003, DOI: 10.1590/S0102-09352003000100005
Abstract: in order to evaluate two therapeutic ultrasound protocols for treatment of injuries of the superficial digital flexor tendon (sdft) a study was performed in 18 horses. in each horse, a 0.25% solution of collagenase was injected in the middle of the left sdft. the horses were randomly and equally divided into three groups. horses from group a were treated with therapeutic ultrasound of 3 mhz frequency and 1 w/cm2 intensity on continuous mode for six minutes; horses from group b were treated with the same frequency, intensity, and time, but on pulsed mode; group c was kept as controls. the treatment began 48 hours after the collagenase injection, totaling eight sessions. the horses were clinically evaluated for 40 days. ultrasonographic images were evaluated weekly to score the severity rate (sr), which was based on echogenicity and cross sectional area of the lesion in the tendon. the induced lesion resulted on an average increase of 1.5cm in the shin circumference, pain response to digital pressure ranging from low to high and lameness ranging from grade 1 to 3. regression of clinical signs were detected on average in nine days in group a, 12 days in group b, and 21 days in group c. decreases of the sr after 40 days were 42.5, 57.7 and 34.1% in groups a, b and c, respectively. histological evaluation demonstrated intense neovascularization and fibroblastic activity on treated groups (a and b), when compared to the controls. these results suggest that ust is effective in reducing clinical signs of tendinitis.
Efeito do ultra-som terapêutico em tendinite experimental de eqüinos: estudo clínico, ultra-sonográfico e histopatológico de dois protocolos
Fernandes M.A.L.,Alves G.E.S.,Souza J.C.A.
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2003,
Abstract: Avaliaram-se dois protocolos de ultra-som no tratamento de les es do tend o flexor digital superficial (TFDS). Foram estudados 18 eqüinos, nos quais foi injetada uma solu o de colagenase a 0,25% no TFDS esquerdo, à altura do ter o médio da regi o metacarpiana. Os eqüinos foram divididos em: grupo A - tratado por ultra-som (UST) na freqüência de 3 MHz e intensidade de 1W/cm2, no modo contínuo, por seis minutos; grupo B - tratado na mesma freqüência, intensidade e tempo, no modo pulsado; e grupo C - controle. Os tratamentos foram iniciados 48h após a indu o da les o, totalizando oito sess es. Os eqüinos foram estudados por 40 dias, avaliando-se o quadro clínico e a regress o dos sintomas. Por meio de exames ultra-sonográficos semanais avaliaram-se a área transversal e a ecogenicidade da les o para estabelecimento do índice de severidade (IS). A les o resultou em aumento médio de 1,5cm na circunferência da regi o metacarpiana, resposta à press o digital de leve a moderada e grau de claudica o de 1 a 3. A regress o dos sintomas ocorreu, em média, nove dias no grupo A, 12 dias no grupo B e 21 dias no grupo C. O percentual de regress o no IS aos 40 dias foi de 42,5, 57,7 e 34,1, respectivamente. A avalia o histológica mostrou neovasculariza o pronunciada e maior atividade fibroblástica nos grupos tratados (A e B) comparados ao grupo-controle. Estes resultados sugerem que o UST é efetivo na redu o dos sintomas clínicos da tendinite.
Generalized drying curves in conductive/convective paper drying
Lima, O.C. Motta;Pereira, N.C.;Machado, M.A.L.S.;
Brazilian Journal of Chemical Engineering , 2000, DOI: 10.1590/S0104-66322000000400018
Abstract: this work presents a study related to conductive/convective drying of paper (cellulose) sheets over heated surfaces, under natural and forced air conditions. the experimental apparatus consists in a metallic box heated by a thermostatic bath containing an upper surface on which the paper samples (about 1 mm thick) are placed. the system is submitted to ambient air under two different conditions: natural convection and forced convection provide by an adjustable blower. the influence of initial paper moisture content, drying (heated surface) temperature and air velocity on drying curves behavior is observed under different drying conditions. hence, these influence is studied through the proposal of generalized drying curves. those curves are analyzed individually for each air condition exposed above and for both together. a set of equations to fit them is proposed and discussed.
Page 1 /814150
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.