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1.
Mar Pollut Bull ; 203: 116455, 2024 May 11.
Article in English | MEDLINE | ID: mdl-38735171

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds ubiquitous in the environment and known for their toxic, mutagenic, and carcinogenic effects. These compounds can bioaccumulate in the biota and be transferred through trophic webs. The franciscana dolphin (Pontoporia blainvillei), as top predators, can be an environmental sentinels. Thus, this study aimed to provide data about PAHs concentration in their hepatic tissue collected on the coast of Espírito Santo (Franciscana Management Area, FMA Ia), Rio de Janeiro (FMA IIa), and São Paulo states (FMA IIb), in Southeastern Brazil. PAHs were detected in 86 % of franciscana dolphins (n = 50). The highest ∑PAHsTotal median concentration was reported in FMA Ia followed by FMA IIb and FMA IIa (1055.6; 523.9, and 72.1 ng.g-1 lipid weight, respectively). Phenanthrene was detected in one fetus and two neonates, showing maternal transfer of PAHs in these dolphins. Evaluating PAHs with potential toxic effects is of utmost importance for the conservation of a threatened species.

5.
Sci Rep ; 12(1): 9292, 2022 06 03.
Article in English | MEDLINE | ID: mdl-35661777

ABSTRACT

This study tests the geometrical parameterization method for Electrical Bio-Impedance Spectroscopy (EBIS) readings previously proposed by one of the authors. This method uses the data of just three frequencies (therefore called 3P method). The test was carried out by the analysis of parameterization from 26 spectra (selected from 13 data sets) by the non-linear square (NLS) method, the 3P method and a combination of the two (3P-NLS). Additionally, the behaviour of the 3P method for 4 levels of noise and 3 different ways of segmenting the spectra were also explored with a MATLAB simulation of 400 spectra. Finally, a system for the classification of EBIS readings is presented, based on deviations of the raw data from the semi-circle obtained by the parameterization methods. Overall, the results suggest a very good performance of the 3P method when compared with the other two. The 3P method performs very well with levels of noise of 1 and 2%, but performs poorly with levels of noise of 5% and 10%. The results support the idea that the 3P method could be used with confidence for the parameterization of EBIS spectra, after the selection of three adequate frequencies according to specific applications.


Subject(s)
Dielectric Spectroscopy , Electricity , Computer Simulation , Dielectric Spectroscopy/methods , Electric Impedance
6.
Braz. j. biol ; 82: 1-4, 2022. ilus, tab
Article in English | LILACS, VETINDEX | ID: biblio-1468502

ABSTRACT

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.


Besouros broqueadores se desenvolvem em árvores vivas e madeira morta, realizando serviços ecológicos como decomposição e regulação de recursos da floresta. Espécies da família Cerambycidae, amplamente distribuídas no mundo, perfuram o caule de árvores e madeira morta em áreas nativas e cultivadas. O objetivo é relatar a primeira planta hospedeira de Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) no bioma da Mata Atlântica brasileira. Três toras, com um metro de comprimento por 20 cm de diâmetro, foram cortadas de uma árvore sadia de Anadenanthera colubrina (Fabaceae) em outubro de 2013 e amarradas no sub-bosque a 1,5m de altura no Parque Estadual do Rio Doce, estado de Minas Gerais, Brasil. As toras, expostas na floresta, foram removidas, cada uma, após 40, 80 e 120 dias e armazenadas, individualmente, em caixas de papelão no “Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)” no Parque Estadual do Rio Doce. Um total de 94 indivíduos de T. lineatocolle e 228 de T. megacephala emergiu das toras de A. colubrina. Esse é o primeiro registro de uma planta hospedeira para T. lineatocolle e o de uma nova planta hospedeira para T. megacephala.


Subject(s)
Animals , Coleoptera/growth & development , Fabaceae
7.
Braz. j. biol ; 822022.
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1468689

ABSTRACT

Abstract Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq) in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.


Resumo Besouros broqueadores se desenvolvem em árvores vivas e madeira morta, realizando serviços ecológicos como decomposição e regulação de recursos da floresta. Espécies da família Cerambycidae, amplamente distribuídas no mundo, perfuram o caule de árvores e madeira morta em áreas nativas e cultivadas. O objetivo é relatar a primeira planta hospedeira de Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) no bioma da Mata Atlântica brasileira. Três toras, com um metro de comprimento por 20 cm de diâmetro, foram cortadas de uma árvore sadia de Anadenanthera colubrina (Fabaceae) em outubro de 2013 e amarradas no sub-bosque a 1,5m de altura no Parque Estadual do Rio Doce, estado de Minas Gerais, Brasil. As toras, expostas na floresta, foram removidas, cada uma, após 40, 80 e 120 dias e armazenadas, individualmente, em caixas de papelão no Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq) no Parque Estadual do Rio Doce. Um total de 94 indivíduos de T. lineatocolle e 228 de T. megacephala emergiu das toras de A. colubrina. Esse é o primeiro registro de uma planta hospedeira para T. lineatocolle e o de uma nova planta hospedeira para T. megacephala.

8.
Braz. j. biol ; 82: e240126, 2022. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1249275

ABSTRACT

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.


Besouros broqueadores se desenvolvem em árvores vivas e madeira morta, realizando serviços ecológicos como decomposição e regulação de recursos da floresta. Espécies da família Cerambycidae, amplamente distribuídas no mundo, perfuram o caule de árvores e madeira morta em áreas nativas e cultivadas. O objetivo é relatar a primeira planta hospedeira de Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) e uma nova planta hospedeira para Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) no bioma da Mata Atlântica brasileira. Três toras, com um metro de comprimento por 20 cm de diâmetro, foram cortadas de uma árvore sadia de Anadenanthera colubrina (Fabaceae) em outubro de 2013 e amarradas no sub-bosque a 1,5m de altura no Parque Estadual do Rio Doce, estado de Minas Gerais, Brasil. As toras, expostas na floresta, foram removidas, cada uma, após 40, 80 e 120 dias e armazenadas, individualmente, em caixas de papelão no "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" no Parque Estadual do Rio Doce. Um total de 94 indivíduos de T. lineatocolle e 228 de T. megacephala emergiu das toras de A. colubrina. Esse é o primeiro registro de uma planta hospedeira para T. lineatocolle e o de uma nova planta hospedeira para T. megacephala.


Subject(s)
Animals , Coleoptera , Colubrina , Fabaceae , Brazil , Forests
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 4253-4256, 2021 11.
Article in English | MEDLINE | ID: mdl-34892162

ABSTRACT

OBJECTIVE: to describe a simple and straightforward method to calculate the circle parameters that can be used to fit Electrical Bioimpedance Spectroscopy (EBIS) raw data to the complex plane and remove the hook effect, a deviation of that model especially seen at higher frequencies and considered as an artifact due to instrumental limitations. APPROACH: under the assumption that raw EBIS data in the middle frequencies best represent the beta dispersion, the authors of this article propose a geometrical procedure to calculate parameters for this dispersion and remove the hook effect. For this purpose, data obtained with two different devices were used with apparently very good results. MAIN RESULTS: the results of this study suggest that circle parameters for the beta dispersion can be obtained, but, also, that the residuals of the hook effect correction seem to adjust to a circle and, therefore, they could also be parameterized using the same approach. SIGNIFICANCE: the method proposed in this article is very easy to perform and could help end EBIS users not familiar with mathematical models and fitting processes, to better understand and interpret their data.


Subject(s)
Artifacts , Dielectric Spectroscopy , Electric Impedance
11.
Braz J Biol ; 82: e240126, 2021.
Article in English | MEDLINE | ID: mdl-34105682

ABSTRACT

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.


Subject(s)
Coleoptera , Colubrina , Fabaceae , Animals , Brazil , Forests
12.
Med Hypotheses ; 108: 133-143, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29055387

ABSTRACT

The hypothesis being advanced in this paper is that there is a new medical paradigm emerging from the biomedical research carried out in this century, mainly due to the explosion of the so called "omics" and associated techniques. The main idea is that there is a common pathway from wellbeing and health to chronic disease ("chronopathy") and even to death, which comprises following steps: 1) unhealthy diet, sedentary life style and permanent exposition to xenobiotics and all kinds of noxious stimuli;→2) intestinal dysbiosis;→3) alteration of the intestinal mucus layer (especially that of the colon);→4) disruption of the endothelial tight junctions;→5) metabolic endotoxemia+bacterial translocation;→6) inflammation;→7) exacerbation of the enteric nervous system (ENS) and consequent maladaptation and malfunctioning of the colon;→8) epigenetic manifestations;→9) "chronopathy" and premature death. Therefore, in order to maintain a good health or to improve or even reverse chronic diseases in a person, the main outcome to look for is a homeostatic balance of the intestinal microbiota (eubiosis), most of which is located in the colon. Lynn Margulis was one of the main scientists to highlight the importance of the role played by bacteria not only in the origin of all biological species now present on earth, but also on their role in global homeostasis. Bacteria do not rely on other living beings for their existence, while the latter depend completely on the former. Humans are no exemption, and new evidence emerges each day about the pivotal role of intestinal microbiota in human health, disease and, in general, in its wellbeing. The following facts about intestinal microbiota are nowadays generally accepted: there are about 10 times more bacteria in the gut than human cells in every human being; the microbioma is about 100-150 times bigger that the human genome, and there is a clear link between intestinal microbiota and many of the most common chronic diseases, from obesity and diabetes to depression and Parkinson disease and different kinds of cancer. The main implication of this theory is that we should become a sort of microbiota farmers, that is, we ought to be more conscious of our intestinal microbiota, take care of it and monitor it permanently. Thus, as part of our good life habits (healthy eating, physical exercise), we should probably undergo periodic seasons of fasting and colon cleansing, as it was common in older times.


Subject(s)
Colon/physiology , Colon/physiopathology , Colonic Diseases/physiopathology , Gastrointestinal Microbiome , Colonic Diseases/microbiology , Endotoxemia/physiopathology , Epigenesis, Genetic , Fasting , Humans , Inflammation , Intestinal Mucosa/physiopathology , Intestines/physiopathology , Models, Theoretical , Neurosecretory Systems , Obesity/complications , Obesity/physiopathology , Parkinson Disease/complications , Parkinson Disease/physiopathology , Permeability , Risk Factors
13.
Med Hypotheses ; 97: 107-111, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27876116

ABSTRACT

Field cancerization is a concept used to explain cellular and molecular alterations in tissue associated to neoplasia and cancer. This effect was proposed by Slaughter in order to explain the development of multiple primary tumors and locally recurrent cancer. The particular changes associated with this effect, in each type of cancer, have been detected even at distances greater than 10cm off the tumor, in areas classified as normal by histopathological studies. Early detection of lung, colon, and ovary cancer has been reported by the use of Partial Wave Microscopy Spectroscopy (PWS) and has been explained in terms of the field cancerization effect. Until now, field cancerization has been studied as a field effect and we hypothesize that it can be understood as an amplifying effect of biochemical abnormalities in cells, which leads us to ask the question: Could field cancerization be interpreted as a biochemical anomaly amplification due to transformed cells? We propose this question because the biochemical changes due to field cancerization alter the dynamics of molecules and cells in abnormal tissues in comparison to normal ones, these alterations modify the interaction of intracellular and extracellular medium, as well as cellular movement. We hypothesize that field cancerization when interpreted as an amplification effect can be used for the early detection of cancer by measuring the change of cell dynamics.


Subject(s)
Cell Transformation, Neoplastic , Neoplasms/diagnosis , Neoplasms/pathology , Biomarkers, Tumor/metabolism , Breast Neoplasms/pathology , Cell Line, Transformed , Colonic Neoplasms/pathology , Female , Humans , Light , Lung Neoplasms/pathology , Male , Neoplasm Recurrence, Local , Neoplasms/metabolism , Ovarian Neoplasms/pathology , Proteomics , Spectrophotometry , Tumor Microenvironment , Uterine Cervical Neoplasms/pathology
14.
Neotrop Entomol ; 41(2): 150-62, 2012 Apr.
Article in English | MEDLINE | ID: mdl-23950027

ABSTRACT

The third instar of the genera Ceraspis, Clavipalpus, Isonychus and Manopus (Melolonthidae: Melolonthinae: Macrodactylini) are described for the first time. Descriptions are based on the larvae of Ceraspis innotata (Blanchard), Clavipalpus ursinus Blanchard, Isonychus maculatus Waterhouse and Manopus biguttatus Laporte. The pupae of C. ursinus, I. maculatus and M. biguttatus are also described. A key to the larvae of nine genera of Macrodactylini and a list of the species with immature descriptions are provided.


Subject(s)
Coleoptera/classification , Coleoptera/growth & development , Animals , Coleoptera/anatomy & histology , Larva/anatomy & histology , Larva/growth & development
15.
Physiol Meas ; 26(2): S39-47, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15798245

ABSTRACT

Electrical bioimpedance spectroscopy (EBIS) is a technique that uses a probe to calculate the transfer impedance from tissues. This transfer impedance can give information about the normal or pathological condition of the tissue. To take readings, pressure has to be applied to the probe in order to get a good contact between the electrodes and the tissue. We have been using EBIS to investigate the early diagnosis of dysplasia and cancer in the human cervix, oesophagus and bladder. We have found that, with increasing pressure (range used here was approximately 1 kPa to approximately 50 kPa), the resistivity readings increase in a consistent way up to 80%. In this paper, we show how this is a case in three different tissue types (oesophageal, gastric and vesical samples). These increases can be higher than those associated with the pathological changes that we are investigating (non-inflamed columnar tissue, for instance, shows values 50% higher than dysplastic columnar tissue). Finite-element modelling was also used to investigate the effect of volume reduction in the connective tissue or stroma. This simulation suggests no strong correlation between reduction of this structure and increase in resistivity. We hypothesize therefore that these changes may be mainly associated with the squeezing of water from the extracellular space. Finally, as pressure is difficult to control by hand, we raise the issue of the necessity of considering this variable when making EIS measurements.


Subject(s)
Connective Tissue/physiology , Diagnosis, Computer-Assisted/methods , Electric Impedance , Electrodes , Models, Biological , Plethysmography, Impedance/methods , Animals , Humans , Organ Specificity , Plethysmography, Impedance/instrumentation , Pressure , Rats , Stress, Mechanical , Transducers
16.
Physiol Meas ; 24(2): 291-6, 2003 May.
Article in English | MEDLINE | ID: mdl-12812415

ABSTRACT

Biological tissues undergoing inflammation and dysplasia seem to exhibit changes in the intercellular space that can be sensed using low frequency electrical impedance methods. Basically, low frequency electric current flows through this space and its widening as well as the disruption of the tight junction decrease the resistance, facilitating current flow. The electrical changes accompanying structural changes from columnar tissue to adenocarcinoma in Barrett's metaplastic mucosa and gastric tissue are illustrated using resected tissue from 32 patients. Two hundred and fifty-eight biopsies were analysed, correlating their electrical resistivity (R) at 9.6 kHz and their histopathological interpretation. Compared to non-inflamed non-dysplastic columnar tissue (R = 4.9 ohms m), the results suggest a small but statistically significant decrease of electrical impedance in columnar tissue showing inflammation (R = 4.2 ohms m, p = 0.016) and a larger decrease when dysplasia is present (R = 3.4 ohms m, p = 0.040). If this method is validated further, this technique could be used to obtain guided biopsies from patients undergoing surveillance programmes for Barrett's oesophagus. We aim to refine this technique using a new system with lower frequencies and, possibly, in vitro (cultured cells) and in vivo (rats) models of Barrett's oesophagus.


Subject(s)
Barrett Esophagus/immunology , Barrett Esophagus/pathology , Electric Impedance , Adenocarcinoma/immunology , Adenocarcinoma/pathology , Biopsy , Epithelial Cells/pathology , Esophageal Neoplasms/immunology , Esophageal Neoplasms/pathology , Esophagus/pathology , Humans , Stomach/pathology
17.
Physiol Meas ; 23(1): 183-8, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11876232

ABSTRACT

This paper reports a preliminary finding associated with an investigation of how tissues respond to mechanical stress. The stress distribution within the tissue may be the result of normal function, for example, joint forces, or it may result from interventions such as tissue suturing during or after surgery. We sought to combine electrical and mechanical computational models in order to better understand the interaction between the two. For example, if mechanical stress is applied to tissue this may change the cell arrangements within the tissue matrix and hence change the electrical properties. If this interaction could be determined, then it should be possible to use electrical impedance tomography measurements to identify stress patterns in tissues. Measurements of resistivity changes have been made in conductive silicone rubber sheets when subject to a uniaxial stress of up to 10%. Relatively large changes in resistivity are produced (up to 200%). These changes are far larger than those predicted arising from topological changes alone. It is suggested that under stress the conductive islands of carbon within the silicone rubber sheet undergo a reversible disassociation from their neighbours and that the material's electrical properties change under load. If similar stress-resistivity relationships occur within biological materials it may be possible to recover the stress fields within tissues from transfer impedance measurements and thereby predict if actions such as inappropriate suture tension will compromise tissue viability.


Subject(s)
Silicone Elastomers , Stress, Mechanical , Algorithms , Electric Conductivity , Electrodes , Tensile Strength
18.
Med Biol Eng Comput ; 38(4): 373-6, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10984933

ABSTRACT

It has previously been shown that it is possible to differentiate between squamous and columnar epithelia in rat and resected human tissues using an impedance probe to make in vitro measurements. This probe can be passed down an endoscope allowing measurements to be made in patients. However, the probe emerges parallel to the oesophageal wall, with little room to manoeuvre. The conditions of control required to give reliable readings have been investigated. The importance of pressure applied and the angle of approach to the oesophagus was assessed. Pressures in the range 26.6 Pa to 46.3 kPa and angles in the range 15-90 degrees were considered. In in vitro studies it was observed that it was possible to obtain consistent readings with pressures greater than 2.9 kPa and with angles greater than 15 degrees between the probe and the oesophagus. These conditions can be achieved in vivo, and readings obtained from twelve patients are shown (45 readings on normal squamous, 34 on Barrett's oesophagus and 22 on stomach). At low frequencies (9.6-153.2 kHz), a Mann-Whitney test shows a significant difference (p < 0.001) when comparing the means from squamous and columnar, and also when readings from Barrett's and normal gastric epithelia are compared (p < 0.001).


Subject(s)
Barrett Esophagus/diagnosis , Electrodiagnosis/methods , Esophageal Neoplasms/diagnosis , Precancerous Conditions/diagnosis , Animals , Electric Impedance , Esophagoscopy , Humans , Pressure , Rats
19.
Ann N Y Acad Sci ; 873: 313-21, 1999 Apr 20.
Article in English | MEDLINE | ID: mdl-10372179

ABSTRACT

Preliminary results of electrical impedance measurements in squamous and columnar epithelia in rat and human tissues are presented. The aim of this work is to show the possibility of differentiating these two types of epithelia in terms of their electrical characteristics. For the measurements, we employed a 1.95-m-long, 3.2-mm-diameter, four-electrode probe designed to be used transendoscopically in the diagnosis of Barrett's esophagus (BE). BE is a condition in which the normal squamous epithelium of the esophagus is replaced by columnar epithelium of the intestinal type. This metaplasia is considered as a premalignant condition that puts patients at a 30-125-fold risk of developing adenocarcinoma of the esophagus. The diagnosis and surveillance of BE involve taking multiple biopsies, an expensive and time-consuming procedure. This study constitutes the first stage in the replacement of tissue biopsy by "virtual biopsies".


Subject(s)
Barrett Esophagus/pathology , Biopsy/methods , Electric Impedance , Animals , Endoscopy, Digestive System/methods , Epithelial Cells/pathology , Esophageal Neoplasms/pathology , Humans , Precancerous Conditions/pathology , Rats
20.
Ann N Y Acad Sci ; 873: 512-9, 1999 Apr 20.
Article in English | MEDLINE | ID: mdl-10372187

ABSTRACT

An EIT system has been produced that has been optimized for imaging impedance changes with scalp electrodes during brain activity in ambulant subjects. It can record from 225 Hz to 65 kHz, has a small headbox on a lead 10 m long, and has software programmable electrode selection. In calibration experiments in a small cylindrical tank filled with potassium chloride solution and samples of cucumber, noise was less than 1% with averaging, and acceptable images were produced at frequencies down to 1800 Hz. This suggests that EIT can be performed at low frequencies, which are likely to give larger signals during brain activity. Future work will include trials in humans and improvement of the current source and isolation.


Subject(s)
Electric Impedance , Tomography/methods , Brain Chemistry , Calibration , Cucumis sativus , Electrodes , Humans , Image Processing, Computer-Assisted , Phantoms, Imaging , Potassium Chloride , Tomography/instrumentation
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