Dissertations / Theses on the topic 'Halothane'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Halothane.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Provenat, Véronique. "Les effets toxiques et allergiques de l'halothane." Paris 5, 1989. http://www.theses.fr/1989PA05P046.
Full textZhang, Ke. "Cardiac electrophysiology and cardiotoxicity of halothane /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487676261012213.
Full textKnight, Trudy Lynn. "The molecular basis of halothane-induced hepatotoxicity." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321782.
Full textSiadat, Pajouh Majid 1959. "GENERATION OF HALOTHANE INDUCED ANTIBODY IN GUINEA PIGS AND ITS POSSIBLE ROLE IN THE PATHOGENESIS OF HALOTHANE INDUCED LIVER INJURY." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276363.
Full textLAUNAY, FREDERIC. "Toxicologie de l'halothane." Strasbourg 1, 1991. http://www.theses.fr/1991STR15020.
Full textMolliex, Serge. "Effets de l'halothane sur les pneumocytes II de rat en culture primaire." Saint-Etienne, 1991. http://www.theses.fr/1991STET6417.
Full textVinh, Vu Huu. "Comparative contractile effects of halothane and sevoflurane in rat aorta." Kyoto University, 2001. http://hdl.handle.net/2433/150545.
Full textGoddard, Helen. "Electrophysiological effects of fentanyl, halothane and isoflurane on guinea-pig isolated ventricular myocytes." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:58f6f4e2-aaa9-4913-a7c2-5568e2f8d72f.
Full textTorske, Kristine E. "An evaluation of epidural oxymorphone and bupivacaine during halothane anesthesia in dogs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0026/NQ31906.pdf.
Full textDarling, John R. "The effects of halothane, isoflurane and sevoflurane on hepatic and renal function." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261937.
Full textSouthwood, Olwen Irene. "Studies on the genetics and dynamics of the halothane gene in pigs." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/14460.
Full textHarris, Natalie K. "Gas detection using semiconducting polymers." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262652.
Full textGérard, Alain. "Determination des caracteristiques cliniques de la crise d'hyperthermie maligne per-anesthesique : analyse d'une serie de 95 propositus classes par les tests de contracture halothane et cafeine." Lille 2, 1994. http://www.theses.fr/1994LIL2M147.
Full textBrown, Alan Perry. "Generation and expression of halothane derived protein adducts in the guinea pig liver." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186218.
Full textLyons, Jeremy D. M. "Effects of anaesthesia and nutrition on immunology and hepatic function in adults and children." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326386.
Full textSassou-Toussaint, Etchrivi. "Effet de l'halothane sur les propriétés mécaniques intrinsèques du muscle squelettique : application à l'hyperthermie maligne." Lille 1, 1995. http://www.theses.fr/1995LIL10054.
Full textOnimus, Jerome. "Dose test en anesthesie locoregionale pediatrique : evaluation de la lidocaine 1 % adrenalinee chez l'enfant anesthesie par halothane." Lille 2, 1994. http://www.theses.fr/1994LIL2M272.
Full textWodey, Eric. "Role de la po2 dans la toxicite hepatique de l'halothane : etude sur primoculture d'hepatocyte de rat." Rennes 1, 1992. http://www.theses.fr/1992REN1M131.
Full textChiari, Pascal. "Effets cardiovasculaires du propofol : a propos d'une etude experimentale ; effets sur les debits sanguins regionaux et l'hemodynamique globale et regionale myocardique compares a l'halothane chez le chien." Lyon 1, 1993. http://www.theses.fr/1993LYO1M258.
Full textHeyer, Laurent. "Effets respiratoires du propofol et de l'halothane chez le jeune enfant." Lyon 1, 1993. http://www.theses.fr/1993LYO1M336.
Full textJaramillo, Cárdenas Jairo [UNESP]. "Estudo comparativo entre a lindocaína e a acupuntura no tratamento da taquicardia ventricular induzida com infusão contínua de dopamina em equinos sob anestesia geral com halotano." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/103779.
Full textUniversidade Estadual Paulista (UNESP)
A alta mortalidade relacionada a anestesia na espécie eqüina em relação à outras espécies, se deve principalmente à depressão cardiovascular. A taquicardia ventricular (TV) é uma das possíveis arritmias observadas durante a anestesia, classicamente tratada com lidocaina. Objetivou-se avaliar os efeitos cardiorrespiratórios da TV induzida por dopamina, na anestesia por halotano em eqüinos, comparando o efeito da lidocaina e acupuntura para o tratamento deste. Seis eqüinos divididos em três grupos (GC: grupo controle; GA: grupo tratado com acupuntura e GL: grupo tratado com lidocaina), foram estudados para comparar o efeito da lidocaina como método convencional, e da acupuntura nos pontos bilaterais associados: pericárdio 6 (Pc 6 - Neiguan) e Coração 7 (C 7 - Shenmen), na TV induzida pela dose arritmogênica da dopamina (DAD). Os eqüinos foram anestesiados três vezes cada um com xilazina, éter gliceril guaiacol, tiopental e halotano com intervalo de uma semana entre cada anestesia. Foram avaliados os parâmetros cardiovasculares (freqüência cardíaca, pressão arterial e eletrocardiografia), respiratórios (freqüência respiratória, capnografía, saturação de hemoglobina e hemogasometría) e escore de recuperação. A DAD foi determinada a partir da infusão de 70 æg/kg/min IV durante 10 minutos sem interrupção, preenchendo o critério determinado como arritmogênico, pela presença de 4 ou mais complexos ventriculares prematuros seguidos, com duração de pelo menos quinze segundos ou TV sustentada. O tempo médio de aparecimento da DAD ou da TV foi de 6,05 0,45 minutos nos animais não tratados e a TV se reverteu espontaneamente aos 2,7 0,2 minutos. O grupo tratado com acupuntura reverteu a TV em um tempo médio de 1,8 0,2 (P<0,05) em comparação do grupo tratado com lidocaina 1,3 0,2 (P<0,01), ambos se mostrando eficientes no tratamento da TV de eqüinos anestesiados com halotano.
The high mortality related to anesthesia in the equine species compared to other species is mainly due to cardiovascular depression. Ventricular tachycardia (VT) is one of the possible arrhythmias observed during the anesthesia classically treated with lidocaine. The purpose of this study was to evaluate the cardio respiratory effects of VT induced by dopamine in horses anesthetized with halothane, comparing the effect of lidocaine and acupuncture for its treatment. Six horses were allocated to three treatments (CG: control group, AG: acupuncture treated group and LG: lidocaine treated group) and were evaluate to compare the effects of lidocaine as a conventional treatment and the acupuncture in the associated bilateral points: pericardium 6 (Pc 6- Neiguan) and heart 7 (H7 - Shenmen) in VT induced by the arrhythmogenic dose of dopamine (ADD). The horses were anesthetized three times each one using xylazine, guaifenesin, thiopental and halothane with one week interval between each anesthesia. Cardiovascular (heart rate, arterial pressure and ECG) and respiratory (respiratory rate, capnometry, hemoglobin saturation and blood gas analysis) parameters and recovery score were evaluated. The ADD was determined by the infusion of 70 mg/Kg/min during 10 minutes without interruption fulfilling the arrhythmogenic criteria by the presence of 4 or more ectopic ventricular contractions during at least 15 seconds or sustained ventricular tachycardia. The mean time for the occurrence of VT or ADD was 6,05 l 0,45 minutes for control animals and the VT reverted spontaneously at 2,7 l 0,2 minutes. The group treated with acupuncture reverted the VT in a mean time of 1,8 l 0,2 (P<0,05) compared to the group treated with lidocaine 1,3l0,2 (P<0,01), both of them showing to be efficacious for the treatment of VT on horses anesthetized with halothane.
Giovanelli, Debora. "Electrochemical detection of gases." Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:fd447153-b6dd-4be1-aae5-4ece5dc36856.
Full textKhazzaka, Aline. "Les protéines de choc thermique-70 kDa (HSPs 70) chez le porc suite à un stress." Lyon 1, 2006. http://www.theses.fr/2006LYO10186.
Full textHeat shock proteins (hsps) consist of a family of conserved proteins induced by heat shock and other environmental stressors. They play a role of molecular chaperones protecting cells against stress and facilitating the fording and the maturation of cellular proteins. The aim of this work was to study the hsps 70 response to stress in pigs of the three halothane (HAL) genotypes (NN, Nn and nn) in the blood, the semi-membranous muscles and cultured fibroblasts. HAL affected the hsps 70 response in vitro at different levels of the organism. Preconditioning leads to an overexpression of hsps 70 protecting cells from heat damage. It confers a normal hsps 70 response to stress in the nn animals. In vivo studies did not show any corelation between hsps 70, preconditioning and meat quality in pigs
David, Jean-Stéphane. "Étude in vitro de l'effet sur myocarde sain et pathologique d'agents de l'anesthésie." Lyon 1, 2006. http://www.theses.fr/2006LYO10034.
Full textThe effects of different anesthetic agents were studied thanks to a papillary muscle model. In rat, protamine induced a negative inotropic effect which was associated to a muscle contracture probably related to calcium overload. Moreover, inotropic response to α - and β-adrenoceptor stimulation was abolished whereas the lusitropic response was preserved, suggesting a site of action situated downstream from cAMP-mediated phosphorylation. In diabetic myocardium, effect of halogenated gas was more important and related to a decrease in myofilament Ca2+ sensitivity. Potentiation of the positive inotropic effect of β-adrenoceptor agonist was preserved in presence of sevoflurane and isoflurane but not halothane. In hamster, sevoflurane induced a positive inotropic effect. Nifedipine abolished it in healthy hamster but enhanced it in cardiomyopathic hamster
Green, Brent Kenneth II. "The Effects of Genotype, Chromium Picolinate Supplementation, Sex, and Their Interactions on Growth Performance, Carcass Characteristics, and Muscle Quality in Pigs." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35853.
Full textBarrows gained faster (P < .001) and consumed more feed (P < .001) than gilts, yielding heavier (P < .001) carcasses, and heavier (P < .05) wholesale cuts. Gilts had less backfat (P < .001) and larger (P < .01) LMA, and tended to gain more efficiently than barrows.
Carrier pigs had lower pH values, higher CIE L* values, higher drip loss, and lower protein solubility (P < .05), all indicators of decreased quality. Chromium supplementation resulted in pork with higher (P<.05) CIE a*, CIE b*, and Chroma C values. Halothane carrier barrows and all gilts that were not fed chromium had lower lipid muscle content than NN barrows (P < .05).
Gilts had higher CIE L* and a* values (P < .001), less lipid, and higher moisture percentage (P < .02) than barrows. Chromium picolinate did not negatively affect pork muscle quality.
Master of Science
McKinney, Maurice Stanley. "Aspects of cardiac function and the influence of age during anaesthesia with isoflurane and halothane." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333778.
Full textKobata, Robert Steven 1954. "AN AUTOMATED METHOD OF MEASURING ISOLATED MUSCLE CONTRACTION (VERAPAMIL, HALOTHANE, CALCIUM-CHLORIDE, MAGNESIUM SULFATE, GUINEA PIG)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277003.
Full textJaramillo, Cárdenas Jairo. "Estudo comparativo entre a lindocaína e a acupuntura no tratamento da taquicardia ventricular induzida com infusão contínua de dopamina em equinos sob anestesia geral com halotano /." Botucatu : [s.n.], 2006. http://hdl.handle.net/11449/103779.
Full textBanca: Denise Saretta Schwartz
Banca: Denise Fantoni
Banca: Renata Navarro Cassu
Banca: Francisco Teixeira Neto
Resumo: A alta mortalidade relacionada a anestesia na espécie eqüina em relação à outras espécies, se deve principalmente à depressão cardiovascular. A taquicardia ventricular (TV) é uma das possíveis arritmias observadas durante a anestesia, classicamente tratada com lidocaina. Objetivou-se avaliar os efeitos cardiorrespiratórios da TV induzida por dopamina, na anestesia por halotano em eqüinos, comparando o efeito da lidocaina e acupuntura para o tratamento deste. Seis eqüinos divididos em três grupos (GC: grupo controle; GA: grupo tratado com acupuntura e GL: grupo tratado com lidocaina), foram estudados para comparar o efeito da lidocaina como método convencional, e da acupuntura nos pontos bilaterais associados: pericárdio 6 (Pc 6 - Neiguan) e Coração 7 (C 7 - Shenmen), na TV induzida pela dose arritmogênica da dopamina (DAD). Os eqüinos foram anestesiados três vezes cada um com xilazina, éter gliceril guaiacol, tiopental e halotano com intervalo de uma semana entre cada anestesia. Foram avaliados os parâmetros cardiovasculares (freqüência cardíaca, pressão arterial e eletrocardiografia), respiratórios (freqüência respiratória, capnografía, saturação de hemoglobina e hemogasometría) e escore de recuperação. A DAD foi determinada a partir da infusão de 70 æg/kg/min IV durante 10 minutos sem interrupção, preenchendo o critério determinado como arritmogênico, pela presença de 4 ou mais complexos ventriculares prematuros seguidos, com duração de pelo menos quinze segundos ou TV sustentada. O tempo médio de aparecimento da DAD ou da TV foi de 6,05 0,45 minutos nos animais não tratados e a TV se reverteu espontaneamente aos 2,7 0,2 minutos. O grupo tratado com acupuntura reverteu a TV em um tempo médio de 1,8 0,2 (P<0,05) em comparação do grupo tratado com lidocaina 1,3 0,2 (P<0,01), ambos se mostrando eficientes no tratamento da TV de eqüinos anestesiados com halotano.
Abstract: The high mortality related to anesthesia in the equine species compared to other species is mainly due to cardiovascular depression. Ventricular tachycardia (VT) is one of the possible arrhythmias observed during the anesthesia classically treated with lidocaine. The purpose of this study was to evaluate the cardio respiratory effects of VT induced by dopamine in horses anesthetized with halothane, comparing the effect of lidocaine and acupuncture for its treatment. Six horses were allocated to three treatments (CG: control group, AG: acupuncture treated group and LG: lidocaine treated group) and were evaluate to compare the effects of lidocaine as a conventional treatment and the acupuncture in the associated bilateral points: pericardium 6 (Pc 6- Neiguan) and heart 7 (H7 - Shenmen) in VT induced by the arrhythmogenic dose of dopamine (ADD). The horses were anesthetized three times each one using xylazine, guaifenesin, thiopental and halothane with one week interval between each anesthesia. Cardiovascular (heart rate, arterial pressure and ECG) and respiratory (respiratory rate, capnometry, hemoglobin saturation and blood gas analysis) parameters and recovery score were evaluated. The ADD was determined by the infusion of 70 mg/Kg/min during 10 minutes without interruption fulfilling the arrhythmogenic criteria by the presence of 4 or more ectopic ventricular contractions during at least 15 seconds or sustained ventricular tachycardia. The mean time for the occurrence of VT or ADD was 6,05 l 0,45 minutes for control animals and the VT reverted spontaneously at 2,7 l 0,2 minutes. The group treated with acupuncture reverted the VT in a mean time of 1,8 l 0,2 (P<0,05) compared to the group treated with lidocaine 1,3l0,2 (P<0,01), both of them showing to be efficacious for the treatment of VT on horses anesthetized with halothane.
Doutor
Pottie, Robert George. "A CLINICAL STUDY OF INHALANT ANAESTHESIA IN DOGS." University of Sydney, 2004. http://hdl.handle.net/2123/559.
Full textBaudy, Yves. "L'examen ophtalmologique sous anesthésie générale de courte durée chez l'enfant." Montpellier 1, 1989. http://www.theses.fr/1989MON11156.
Full textJuvin, Philippe. "Régulation du métabolisme des pneumocytes II : effets des halogénés et des particules diesel." Paris 7, 2001. http://www.theses.fr/2001PA077263.
Full textGatecel, Claire. "Incidence de l'halothane et de l'isoflurane sur les debits sanguins arteriels hepatiques et veineux porte chez l'homme mesures par methode doppler pulse avec microcapteurs implantes : validation de la methode." Rennes 1, 1992. http://www.theses.fr/1992REN1M022.
Full textIto, Tatsuya. "Reversible inhibition of hypoxia-inducible factor 1 activation by exposure of hypoxic cells to the volatile anesthetic halothane." Kyoto University, 2002. http://hdl.handle.net/2433/149718.
Full textSobair, Abbas Taha Hamza. "The influence of body temperature on MAC of halothane in the rabbit determined using controlled mechanical and heat stimulation." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/30002.
Full textFreeman, Lisa C. "The effects of halothane on impulse propagation in Purkinje fibers and across the Purkinje-muscle junction during [alpha]-adrenergic stimulation /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487673114114476.
Full textHashiguchi(Ikeda), Mitsuko. "Halothane inhibits an intermediate conductance Ca[2+]-activated K[+] channel by acting at the extracellular side of the ionic pore." Kyoto University, 2004. http://hdl.handle.net/2433/145289.
Full textNyström, Per-Erik. "Quantitative trait loci in pig production /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5712-2.pdf.
Full textJúnior, Ewaldo de Mattos. "Avaliação biespectral, cardiorrespiratória e hemogasométrica em cadelas submetidas a ovariosalpingohisterectomia, tratadas com acepromazina associada ou não a meperidina e anestesiadas com halotano, isofluorano ou sevofluorano." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/10/10137/tde-17112008-153956/.
Full textThe objective of this study was evaluation effects of the halothane, isoflurane and sevoflurane on bispectral index, cardiopulmonary and hemogasometrics parameters in bitches undergoing ovariohysterectomy. Fourth-eight mongrel bitches (weight: 15,09±4,29 kg) with 3,9±1,23 years old, send to HOVET-USP for surgical procedure of ovariohysterectomy. The animals were randomly allocated in six grupos of eight animals, designed with AH, AMH, AI, AMI, AS e AMS. The animals of the AH, AI and AS group were premedicated with acepromazine (0,1 mg.kg-1, i.m.) and the animals of the AMH, AMI and AMS groups receive acepromazine (0,05 mg.kg-1, i.m.) and meperidine (3 mg.kg-1, i.m.). Fifteen minutes later, propofol was titrated to allow endotracheal intubation and connected in valvular circuit of anesthesia machine and was maintained in spontaneously breathing with halotane (groups AH and AMH), isoflurane (AI and AMI) and sevoflurane (AS and AMS) in 100% oxygen delivery. Bispectral index (BIS), heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), rectal temperature (RT), respiratory rate (RR), end-tidal of carbon dioxide (ETCO2), peripheral oxihemoglobin saturation, relationship of the arterial oxygen pressure and inspiration fraction of oxygen, inspiration fraction of anesthetics, end-tidal anesthetics, and gasometrical parameters (pH, PaCO2, PaO2, HCO3- and BD) was evaluated. The parameters was evaluated in all groups in moments M0 to M5, M0 fifteen minutes after de pre-medication administration; M1, ten minutes of anesthetic maintains; M2, transfixation of left ovarian; M3 muscle suture; M4, skin suture, M5, ten minutes of the end of anesthetic. All groups were having strong correlation of the bispectral index and end-tidal anesthetic. The AMH group has minor values of bispectral index in M2 when compare with AI, AMI and AS groups; in this moment AI group present to values when compare with AMS. The cardiovascular parameters havent difference between groups. All agents caused reduction of respiratory function, evidenced for increase in PaCO2 and acidemia. The tree agents has inverse correlation with bispectral index, the AMS group, present minor values of BIS, all agents promoted cardiovascular stability and decrease of respiratory function.
Gray, Deborah Lynn. "The effects of cocaine and two major metabolites on epinephrine induced cardiac arrhythmias, electrocardiographic parameters, and mortality in halothane anesthetized male Sprague-Dawley rats /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487682558446853.
Full textMercier, Frédéric. "Anesthésiques halogènes et réactivité bronchique : étude chez le cobaye et chez l'homme." Paris 5, 2002. http://www.theses.fr/2001PA05WO72.
Full textKaikarienė, Veslava. "Laukinių ir naminių kiaulių HAL geno tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140305_141919-10643.
Full textThe aim of present study was to research halothane gene in wild and domestic pigs. Research methodology. Research was performed during 2012 – 2013 year in LSMU Biological Systems and Genetic Research Institute of K. Janusauskas Animals Genetic Laboratory. Samples for DNA testing were collected from wild and domestic pigs. Fattening and meat quality data were obtained from the State of Pigs Control fattening Station of Kaunas Department. A total of 137 pigs (45 wild boars, 5 Vietnamese pigs, 12 Pecari, 25 Landrace, 25 Yorkshire and 25 Pietrian) were tested for halothane genotype. For the effect of HAL gene on meat and fattening properties, 45 crossbreeds (LxJxP) from State Pigs Breeding Station were selected. Plucked hair was used as a source of genomic DNA. All tested animals were characterized as normal homozygotes (NN), heterozygotes (Nn) or recessive homozygotes following amplification of a target region of the HAL gene using the polymerase chain reaction (PCR), followed by a restriction endonuclease assay. The resulting PCR was digested with the restriction enzyme Alw21I, followed by agarose gel electrophoresis. Results and conclusions. In 75 tested domestic pigs, 88 % were NN and 12 % were Nn genotype. In 62 tested wild pigs all animals were NN genotipe. The frequency of n allele was higher (p<0.01) in Petrian pigs (0.25 for n) than in Landrase (0.1 for n) and Yorkshire (0.05 for n). The frequency of N allele was higher in Yorkshire than in the rest of the tested... [to full text]
Yerle-Bouissou, Martine. "Contribution à la carte génique du porc par hybridation moléculaire in situ sur des chromosomes en métaphase et en fin de prophase : application à l'étude du gène halothane." Toulouse, INSA, 1990. http://www.theses.fr/1990ISAT0018.
Full textFreitag, F?bio Batista. "Encoding mechanisms based on fast oscillations in the retina of the cat and their dependencies on anesthesia." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17028.
Full textCoordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Processing in the visual system starts in the retina. Its complex network of cells with different properties enables for parallel encoding and transmission of visual information to the lateral geniculate nucleus (LGN) and to the cortex. In the retina, it has been shown that responses are often accompanied by fast synchronous oscillations (30 - 90 Hz) in a stimulus-dependent manner. Studies in the frog, rabbit, cat and monkey, have shown strong oscillatory responses to large stimuli which probably encode global stimulus properties, such as size and continuity (Neuenschwander and Singer, 1996; Ishikane et al., 2005). Moreover, simultaneous recordings from different levels in the visual system have demonstrated that the oscillatory patterning of retinal ganglion cell responses are transmitted to the cortex via the LGN (Castelo-Branco et al., 1998). Overall these results suggest that feedforward synchronous oscillations contribute to visual encoding. In the present study on the LGN of the anesthetized cat, we further investigate the role of retinal oscillations in visual processing by applying complex stimuli, such as natural visual scenes, light spots of varying size and contrast, and flickering checkerboards. This is a necessary step for understanding encoding mechanisms in more naturalistic conditions, as currently most data on retinal oscillations have been limited to simple, flashed and stationary stimuli. Correlation analysis of spiking responses confirmed previous results showing that oscillatory responses in the retina (observed here from the LGN responses) largely depend on the size and stationarity of the stimulus. For natural scenes (gray-level and binary movies) oscillations appeared only for brief moments probably when receptive fields were dominated by large continuous, flat-contrast surfaces. Moreover, oscillatory responses to a circle stimulus could be broken with an annular mask indicating that synchronization arises from relatively local interactions among populations of activated cells in the retina. A surprising finding in this study was that retinal oscillations are highly dependent on halothane anesthesia levels. In the absence of halothane, oscillatory activity vanished independent of the characteristics of the stimuli. The same results were obtained for isoflurane, which has similar pharmacological properties. These new and unexpected findings question whether feedfoward oscillations in the early visual system are simply due to an imbalance between excitation and inhibition in the retinal networks generated by the halogenated anesthetics. Further studies in awake behaving animals are necessary to extend these conclusions
O processamento da informa??o visual se inicia na retina. A sua complexa rede de c?lulas com diferentes propriedades permite que a informa??o visual seja codificada em canais paralelos e transmitida para o n?cleo geniculado lateral (LGN) e o c?rtex. Na retina, tais respostas est?o frequentemente acompanhadas por oscila??es sincronizadas de alta frequ?ncia (30 90 Hz) em uma maneira dependente do est?mulo. Como demonstrado em estudos na r?, coelho, gato e macaco, respostas oscilat?rias ocorrem em geral a est?mulos relativamente grandes, podendo codificar propriedades globais do est?mulo como o tamanho e continuidade (Neuenschwander and Singer, 1996; Ishikane et al., 2005). Al?m disso, registros simult?neos em diferentes n?veis do sistema visual t?m mostrado que o padr?o de oscila??o nas c?lulas ganglionares retinianas ? transmitido para o c?rtex visual via LGN (Castelo-Branco et al., 1998). De uma forma geral, esses resultados sugerem que oscila??es sincronizadas em uma maneira feedforward s?o importantes na codifica??o da informa??o visual. No presente estudo feito no LGN de gatos anestesiados, investigamos o papel das oscila??es retinianas no processamento de informa??o visual atrav?s da apresenta??o de est?mulos complexos, como cenas naturais, pixels aleat?rios no tempo e espa?o, al?m de grades em movimento. Esse ? um importante passo para o entendimento de mecanismos de codifica??o em condi??es naturais, j? que grande parte dos estudos que investigaram o papel de oscila??es retinianas utilizaram-se de est?mulos simples e estacion?rios. An?lises de correla??o de respostas neuronais (spiking responses) confirmaram resultados pr?vios mostrando que respostas oscilat?rias na retina (observadas aqui a partir de registros no LGN) dependem do tamanho e estacionariedade do est?mulo. Para filmes de cenas naturais (em escala de cinza e preto e branco) oscila??es apareceram apenas por breves momentos provavelmente quando os campos receptores foram dominados por padr?es extensos e cont?nuos (para ambas as escalas). As atividades oscilat?rias parecem ser dependentes de uma massa cr?tica de c?lulas ativadas sugerindo que esse padr?o regular de atividade surge atrav?s de intera??es horizontais na retina. Nossos resultados mostram, al?m disto, que surpreendentemente oscila??es da retina no gato s?o dependentes da anestesia mediada por halotano. Na aus?ncia deste, atividades oscilat?rias estiveram ausentes independentemente das caracter?sticas dos est?mulos visuais. Resultados semelhantes foram obtidos para o isoflurano, anest?sico com propriedades farmacol?gicas similares. Esse novo e inesperado resultado nos faz questionar se oscila??es feedforward no sistema visual n?o seriam resultado de um desequil?brio entre correntes de excita??o e inibi??o nas redes retinianas gerado pelos anest?sicos halogenados. Experimentos futuros em animais acordados ser?o necess?rios para confirmar essas conclus?es
Gueugniaud, Pierre-Yves. "Contractilité myocardique et agents anesthésiques halogénés : de l'étude expérimentale in vitro à l'approche clinique par débitmétrie aortique écho-Doppler." Lyon 1, 1998. http://www.theses.fr/1998LYO1T221.
Full textSaunier, Claude François. "Interactions entre l'anesthésie générale et le système noradrénergique du Locus Coeruleus : approche expérimentale chez le rat." Lyon 1, 1997. http://www.theses.fr/1997LYO1T238.
Full textSingaram, Vinod Krishnan. "The Role of Neuronal Leak Channels in Anesthesia." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1339372305.
Full textOrliaguet, Gilles. "Effets diaphragmatiques des médicaments utilisés en anesthésie au cours du développement postnatal." Paris 6, 2002. http://www.theses.fr/2002PA066278.
Full textKuhn, Mathias. "Vergleichende Untersuchung von Halothan und Isofluran während laparoskopischer Eingriffe beim Pferd." [S.l. : s.n.], 2003. http://dol.uni-leipzig.de/pub/2003-52.
Full textSchmucker, Nicola. "Duplexsonographische Untersuchung kopfversorgender Gefässe beim Pferd unter Halothan-Narkose in verschiedenen Lagerungen /." [S.l.] : [s.n.], 1997. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Full textWenger, Sandra. "Die Kurznarkose zur Ferkelkastration mit Halothan : eine Feldstudie zur Überprüfung der Machbarkeit, des Aufwandes und der Kosten /." [S.l.] : [s.n.], 2001. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Full text