Vera Maura Fernandes de Lima

Vera Maura Fernandes de Lima
CNEN - Comissão Nacional de Energia Nuclear | CNEN · Centro de Biotecnologia- IPEN São Paulo SP

MsC Biomedical Engineering, COPPE UFRJ MD Degree UNESP - SP PhD degree UNiversity of Washington, Seattle

About

74
Publications
45,756
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
750
Citations
Citations since 2016
25 Research Items
227 Citations
20162017201820192020202120220204060
20162017201820192020202120220204060
20162017201820192020202120220204060
20162017201820192020202120220204060

Publications

Publications (74)
Article
Two mathematically distinct physiological concepts, the Goldman-Hodgkin-Katz eq. (GHK eq.) and the Hodgkin-Huxley model (HH model) were successfully associated with each other in a prior work. The previous work was performed on the following premises (i) The membrane potential is generated by ion adsorption, as opposed to the classical ion transpor...
Preprint
Full-text available
Neste texto apresentamos a proposta de um método geométrico buscando representar fenômenos de alta complexidade no campo da psicologia e da neurociência cognitiva. Sabemos que a busca de modelos explicativos com algum grau de formalização, está presente em diferentes campos da psicologia, como, por exemplo, nos trabalhos de Lewin (1973), Piaget (19...
Article
Full-text available
Abstract: At the transition from quiescence to propagating waves recorded in isolated retinas, a circular electric current closes in the extracellular matrix; this circular current creates a magnetic torus flow that, when entering quiescent tissue in front of the wave, recruits elements and when leaving behind, helps to build the absolute refractor...
Article
Full-text available
In this manuscript, we interpret the implications of a discovery we made in 1993 for the understanding of the spread of excitation waves in axon, central gray matter (isolated retina) and heart. We propose that the initial burst of energy dissipation in these waves measured as potentials drops, ionic activities marked changes or optical properties...
Article
Despite the long and broad acceptance of the Goldman - Hodgkin - Katz equation (GHK eq.) and the Hodgkin - Huxley equation (HH eq.) as strong tools for the quantitative analysis of the membrane potential behavior, for a long time they have been utilized as separate concepts. That is the GHK eq. and the HH eq. have not been associated with each othe...
Preprint
Full-text available
At the transition from quiescence to propagating waves recorded in isolated retinas, a circular electric current closes in the extracellular matrix; this circular current creates a magnetic torus that, when entering quiescent tissue in front of the wave, recruits elements and when leaving behind, helps to build the absolute refractory state. The wa...
Research Proposal
Full-text available
This protocol propposes the use of polyarginines (like protamines) to block the eosinophills attachment to glycocalix, cutting the eosinophills/ monocytes macrofagues interaction and lessening the inflammatory response
Research Proposal
Eu desejo discutir esse protocolo terapeutico com meus colegas médicos, principalmente os imunologistas e patologistas com experiencia em transplante ou que tenham acesso a cultura de Human SH-SY5Y neuroblastoma cells . ACh activate the cells using a muscarinic pathway. Test this effect in he presence or absence of protamine. A fast test. I predict...
Chapter
Full-text available
In this chapter we published patch-clamp recorded in intact tissue. With these experiments we learned three important facts. 1- at the spatial scale of a patch pippette, the membrane "physiological" physiological response to light input looked tha same as the pathological' patch response at wave onset, suggesting no breakdown or dramatic event occu...
Preprint
Full-text available
In this paper we interpret the implications of a discovery we made in 1993 for the understanding of the spread of excitation waves in axon, central grey matter (isolated retina) and heart. We propose that the initial burst of energy dissipation in these waves measured as potentials drops, ionic activities marked changes or optical properties being...
Data
Experiments on the effect of liquid deuterium on incorporated peptide (Alamehacin) in lipid bilayer. The solvent effect alters the kinetics of the recorded currents.
Raw Data
The video is of the same wave shown in the previous video. The difference is that the play frame rate is twice faster than the previous in order to show the full optical profile of a solitary circular wave; the full profile has two peaks or components (see bellow). The stimulating electrode is very close but does not touch the retina surface, it re...
Raw Data
this video shows how the acquisition of the extracellular potential drop (in withe) and the optical signals in (red) time series is made simultaneously with the frames that show the propagation wave using PIP (picture on picture software) The first optical peak is related to membrane events. The hydroionic changes include an alkaline pH shift, meas...
Raw Data
This video and the other two labelled beguining with GLU are from the same experiment in isolated chick retina. They provide the panoramic view of the temporal evolution of excitotoxic response of the CNS. The evolution of the whole tissue (only the axons of the optic nerve were cut the retinal network remains structurally intact). It is a free for...
Raw Data
The video shows the evolution of excitotoxic response and the protective effect of reduced GHS added to the perfusion solution. It beguins at 1.5 hours after the ouabain pulse. Note that the propagation of excitotoxic macroscopic edema is contiguous. Histology of similar edemas showed acute cell lsysis. Note also that the glial network of these ret...
Poster
Full-text available
Poster presented at the 10th Experimental chaos conference held in Catania in 2009 in which we presented the results of applying liquid deuterium as solvent in two experimental models of excitable media
Data
A laser red light (low energy) illuminated a region of a live retina that was in focus in light microscope> A propagating excitation wave invades the area in focus (for details look at DOI:10.4236/ojbiphy.2015.51001). With a pen laser and a commom microscope one can obtain a functional histology. Note that maximum brightness of the IOS is at the in...
Raw Data
this very short movie shows a quieescent surface of a retina attached to the eyecup. A gentle touch from a needle is enough to elicit a spreading depression wave visible dua to the strong Intrinsic optical signal
Raw Data
The video shows a metal needle creating a micro lesion and eliciting a spreading depression wave in a retina. The strong stimulus also creates a circular wave. The are stimulated is at the border of the optic nerve pappilla. Note that neither the Intrinsic Optical signal or the spread change, although the structural change in the tissue is remarkab...
Article
Full-text available
We review the concepts and findings that may be related to the occurrence of non-linear glial/neural dynamics involving interactions between polyelectrolytes of the extracellular matrix and the basement membranes that cover the endfeet of glia at CNS interfaces. Distortions of perception and blocking of learning expressed in functional syndromes ar...
Article
Full-text available
In this paper we make the assertion that the key to understand the emergent properties of excitable tissue (brain and heart) lies in the application of irreversible ther-modynamics. We support this assertion by pointing out where symmetry break, phase transitions both in structure of membranes as well as in the dynamic of interactions between membr...
Article
Full-text available
Several explanations have been proposed to account for the mechanisms of neuroglial interactions involved in neural plasticity. We review experimental results addressing plastic nonlinear interactions between glial membranes and synaptic terminals. These results indicate the necessity of elaborating on a model based on the dynamics of hydroionic wa...
Article
Full-text available
In isolated chick retina, the visualization of electrochemical self-organized patterns is possible due to the presence of macroscopic intrinsic optical signals (IOSs). Isolated circular waves, standing patterns, and self-sustained sequences of spirals are all easily obtained using an IOS approach. In this paper we present the tight coupling and non...
Article
Full-text available
In preclinical neuropharmacological research, molecular, cell-based, and systems using animals are well established. On the tissue level the situation is less comfortable, although during the last decades some effort went into establishing such systems, i.e. using slices of the vertebrate brain together with optical and electrophysiological techniq...
Article
Self-similarity has been considered to be present in most of the spatial pattern formation phenomena occurring in natural contexts. In the case of the spreading depression (SD), there are conjectures about the presence of self-similarity in the circular wave formations. Shiner–Davison–Landsberg (SDL) complexity measure framework has been used in se...
Article
Full-text available
Unlabelled: Cationic peptides (polylysines and polyarginines) are being developed as drug delivery systems to nuclei. Therefore, a detailed description of tissue response changes upon the application of cationic peptides over intact basement membranes of excitable tissue is of interest in pharmacology. In this paper we examine the effects of two n...
Article
Background Crotamine is a small, highly basic myotoxin from the venom of the South American rattlesnake Crotalus durissus terifficus. It is structurally well defined and exhibits some similarities with the β-defensins of vertebrates. An amazing variety of functions and targets that range from analgesia and tumor-related activity to cell penetration...
Article
Cationic peptides are being developed as drug delivery systems to nuclei. Therefore, to investigate how such peptides interact with neuronal tissue and membranes, and how this interaction changes tissue response, are useful questions in pharmacology. Protamine and crotamine are both naturally occurring cationic peptides and both can acquire high el...
Article
Full-text available
In this century, the IT technology will spread intelligent systems based on cameras, sensors and computers across all fields of the human endeavor. The systematization of knowledge will reach new levels of organization and applications. Scientific knowledge will not be an exception. In this paper we present the results of validation tests made with...
Article
Gyroxin is a glycoprotein isolated from rattlesnake venom, with known thrombin-like serine protease properties and behavioral action in the CNS. The mechanism of the latter has eluded experimenters for three decades. In this paper about the in vitro chick retina we demonstrate an excitotoxic CNS action of Gyroxin by observing retinal Intrinsic Opti...
Article
Pattern formation, oscillations and wave propagation as processes in excitable media can be controlled by small external forces including gravity. The Belousov–Zhabothinsky (BZ) reaction is possibly the best studied system and exhibits temporal as well as spatial patterns. Wave propagation in BZ systems already has been shown to depend on gravity,...
Article
Full-text available
Oscillating chemical bulk reactions of the Belousov–Zhabotinsky (BZ) type usually show a well-defined periodical color change representing the underlying chemical reactions. Models including up to more than 50 coupled reactions have been developed to describe the BZ-reaction in detail, however, typically a much simpler set of equations is used (i.e...
Article
Excitotoxic central nervous system (CNS) response is believed to be important in the pathophysiology of irreversible sequelae of anoxia and brain trauma. Furthermore, the sodium pump has been associated with functional CNS syndromes such as migraine and epilepsy. Thus, a detailed description of the kinetics of excitotoxic responses elicited by glut...
Article
Full-text available
Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifesta-tions of several functional neurological syn-dromes (migraine aura, epilepsies). Detailed descriptions of these patterns in central grey matter and their physicochemical or pharma-cological manipulations can be useful in many scientific fields ranging from...
Chapter
Full-text available
Our experiments in BZ systems oscillating in time demonstrate a reduced excitability, due to the delayed onset of the oscillations. The temporal behaviour results confirm data from previous papers, arguing that the main difference in heavy water in this case is due to
Article
Full-text available
Cross-sectional study. To observe if there is a relationship between the level of injury by the American Spinal Cord Injury Association (ASIA) and cortical somatosensory evoked potential (SSEP) recordings of the median nerve in patients with quadriplegia. Rehabilitation Outpatient Clinic at the university hospital in Brazil. Fourteen individuals wi...
Article
Full-text available
The isolated chick retina provides an in vitro tissue model, in which two protocols were developed to verify the efficacy of a peptide in the excitability control of the central gray matter. In the first, extra-cellular potassium homeostasis is challenged at long intervals and in the second, a wave is trapped in a ring of tissue causing the system...
Article
The Belousov–Zhabothinsky (BZ) reaction is a chemical reaction which exhibits spatial as well as temporal pattern formation. Being an excitable medium, it can be influenced by even small external forces. One of these small forces which under ground conditions permanently is given is gravity. The gravity dependence of the BZ-reaction has been invest...
Article
Full-text available
According to its physicochemical properties, neuronal tissue, including the central nervous system (CNS) and thus the human brain, is an excitable medium, which consequently exhibits, among other things, self-organization, pattern formation and propagating waves. Furthermore, such systems can be controlled by weak external forces. The spreading dep...
Article
The craniocervical junction (CCJ) comprehends the brainstem, proximal cervical spinal cord and cerebelar structures and is subjected to several congenital anomalies and anatomic variations. Although the morphological abnormalities are present at birth, many patients develop symptoms after third and fourth decades. Magnetic Ressonance Imaging (MRI)...
Chapter
The human brain may behave as an excitable medium, at least up to a certain degree. Although increasing evidence supports this statement, the experimental basis for investigations in the field is small. However, the spreading depression, a propagating wave of depression of the electrical activity in neural tissue, is a tempting example of self-orga...
Article
Neuronal tissue and especially the central nervous system (CNS) is an excitable medium. Self-organisation, pattern formation, and propagating excitation waves as typical characteristics in excitable media consequently have been found in neuronal tissue. The properties of such phenomena in excitable media do critically depend on the parameters (i.e....
Article
Full-text available
Biological and chemical systems in which the pattern of flow of energy and matter imposes self-organization can be seen as examples of excitable media. One property of such media is the presence of excitation waves. The Belouzov-Zabotinsky(B-Z) reaction system and the retinal spreading depression wave are examples of experimental models of excitabl...
Article
In this study the influence of gravity on the velocity of propagating waves in excitable media was investigated in the retinal spreading depression (SD) and in gels of the Belousov–Zhabotinsky (BZ) reaction. It is assumed that in both systems diffusion and convection is small. Compared with liquids, convection in a gel should be absent or should be...
Article
Full-text available
Excitation waves and other no-propagation excited states change the optical properties of central gray matter. In transparent tissue, as the retina and the lens are, the intrinsic optical signals (IOS) are macroscopic. This optical signal is created by light scatter and has different components at the red and blue end of the spectrum. The scatter o...
Article
Full-text available
The brain is an excitable media in which excitation waves propagate at several scales of time and space. "One-dimensional" action potentials (millisecond scale) along the axon membrane, and spreading depression waves (seconds to minutes) at the three dimensions of the gray matter neuropil (complex of interacting membranes) are examples of excitatio...
Article
This paper presents some results on the correlation between the electrophysiological and intrinsic optical signals (IOS) of spreading depression waves in chicken retinae. We first show that the peak of the time derivative of the electrophysiological wave occurs precisely when the optical signal reaches the electrode tip. Second, by comparing bath a...
Article
The retinal spreading depression (SD) is a propagating wave in an excitable medium, the neuronal tissue of the retina. Its velocity is about 3 mm/min and it is accompanied by a variety of changes in the tissue, including electrical and optical events. The pronounced intrinsic optical signal (IOS) of the retinal SD makes it an extremely versatile to...
Article
Full-text available
A mathematical transcription of the intrinsic circuit of the CA1 region of the rat dorsal hippocampus was made and the model parameters adjusted according to experimental data from intracellular recordings and single channel kinetics. This model was able to simulate well the profile of the field potentials recorded extracellularly and the well know...
Article
The onset and propagation of waves in an excitable medium were investigated using the retinal Spreading Depression (rSD). The rSD is an ideal tool for this purpose. The retina of chicken, which was used in all experiments, is a close to two-dimensional system, in which the wave can easily be observed by optical techniques in time and space. rSD wav...
Article
Spreading depression (SD) is a propagating wave of neuronal activity in the central nervous system and may play a role in triggering classical migraine. The retina serves as a model system for examining the phenomenon of SD and the influence of various drugs on it. After a SD wave passes a new wave can not be elicited in the absolute refractory per...
Article
Coupling between cells of neuronal tissue can be due to electrical or chemical synapses. The molecular basis of an electrical synapse is the gap junction channel. Gap junctions have been found between neurones and glial cells, however, in some tissue their presence in the membranes of different cell types is still under discussion. In the retina of...
Article
Patch-clamp experiments are well suited to investigate membrane transport processes on the molecular level. Such experiments can be performed on isolated cells, fragments of cells, and cells in tissue of different degrees of integration, under physiological or pathological conditions. We have used the chicken retina, which is a true piece of centra...
Article
This review deals with a phenomenon which, although it has been known for five decades, has not been recognized until recently as a suitable tool for investigations of neuronal-glial interactions and the interesting consequences of the non-linearities arising from these cooperative effects, such as the transition from quiescent states to the propag...
Article
Full-text available
To describe the spatio-temporal patterns of excitable media, the relationship between frequency and propagating velocity of a wave (dispersion relation) is an important issue. Spreading depression (SD) waves in the brain and especially in the retina are an example of self-organized waves in excitable media (here in neuronal tissue). In the retina s...
Article
Gangliosides are amphiphilic, sialic acid-containing glycosphingolipids which are found preferentially in complex composition in the cellular membranes of the nervous system of vertebrates, including the vertebrate retina as well as in other membranes. They are always exposed to the extracellular side of the membranes. By virtue of the negative cha...
Conference Paper
Full-text available
Presents two manipulations done on the perfusion solution during the propagation of the spreading depression waves in the in-vitro chicken retina. For the first time, the electrophysiological and optical signals were acquired simultaneously. Comparing both of them, the authors show the relationship of the characteristic slow potential shift to the...
Article
The chicken retina is an easily accessible piece of grey matter with a very prominent but simplified neuropil, the inner plexiform layer, which is formed mainly by synaptic terminals and Müller cell processes. In this preparation a self-sustained form of "spreading depression" waves, the circling wave, can be recorded for many hours. We have found...
Article
The retinal spreading depression has been used as a tool to investigate the action of nitric oxide (NO) as a diffusible neurotransmitter which in many cases acts by raising the cGMP level in target cells. The role of NO as a vasodilating agens has been well-established and it has been suggested that the vasodilatation concurrent with cortical SD ma...
Article
The retina is the most accessible piece of central gray matter in the vertebrate brain. Its wide dynamic operational range makes it the ideal neuronal network to study its excitability. Spreading depression waves in the retina are accompanied by strong intrinsic optical signals (IOS) and thus can be measured non-invasively with optical methods. Add...
Article
The chicken retina is an accessible piece of intact gray matter in which a self-sustained form of the 'Spreading Depression' (SD) wave can be easily elicited and recorded for many hours with double barrel ion-sensitive electrodes in the extracellular space. The blockade of glial (Müller) cell potassium channels with barium chloride added to the per...
Article
The role of the forebrain commissures and the septal area in the interhemispheric transfer of hippocampal afterdischarges (ADs) was investigated in the rat under halothane anesthesia. Electrical seizures were elicited from the dorsal hippocampus before and after commissurotomy. The degree of relatedness between EEG signals recorded from homologous...
Article
Full-text available
Afterdischarges (ADs) were elicited in the hippocampus of the rat under halothane anesthesia. Records were made along the septo-temporal axis of the hippocampal formation (dorsal (DHF), splenial (SP) and ventral (VHF) regions). For comparison records were also made from the contralateral DHF. The propagation of ADs was quantified using linear and n...
Article
Brief electrical pulses were applied to the pulp of individual pre-molar teeth of 14 healthy, adult volunteers via wire electrodes implanted and sealed in dentine. The sensation threshold was estimated in each individual by the Two-Alternative Forced-Choice Staircase (2AFCS) method. Seven, 5 or 4 stimulus intensities were employed which were equall...
Article
Individual premolar teeth of 22 normal volunteers were stimulated via intradentinal electrodes using brief electrical pulses. Questionnaires were used to determine the qualities of sensations produced by this stimulation. Operationally defined 'innocuous' sensations predominated between 1 and 10 dB SL, and were absent above 30 dB SL. Similarly defi...
Article
Objective: to evaluate if there is a relationship between somatosensory evoked potential (SSEP) of tibial nerve of people with paraplegia and classification of ASIA (American Spinal Injury Association) and to assess the difference intra- and inter- group in the latency's values of the tibial SSEP. Methods: ten individuals with paraplegia (Group 1),...

Questions

Questions (12)