982 resultados para baroreceptor reflex


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Objectives: To assess the palpebral position in patients with congenital or acquired ptosis, related to margin, sulcus and eyebrow, trying to identify differences between types of ptosis. Methods: A retrospective evaluation of patients with palpebral ptosis treated at the Ambulatory of Ophthalmic Plastic Surgery - Faculdade de Medicina de Botucatu (UNESP) was conducted, from 1995 to 2006. Data were recovered from electronic medical charts as well as digital image files. Eighty-seven patients were assessed, according to age, gender and data related to ptosis, such as time of appearance and type of palpebral ptosis. Palpebral ptosis was classified in two groups: congenital and acquired ptosis. Measurements were taken of margin-reflex distance (MRD), margin sulcus distance (MSD) and margin eyebrow distance (MED) using digital measurements of photos obtained. The corneal diameter of each individual patients was the unit of measure used. All data was transferred to an Excel Spreadsheet and received statistical treatment. Results: Statistical analysis revealed there is no association between the presence of ptosis and gender, or the type of ptosis and gender. There was a significant difference between eyelid with and without ptosis for MRD. However, in relation to the type of ptosis (congenital or acquired), MRD did not present any significant difference. The MSD and MED measurements were higher in acquired ptosis when compared to congenital ptosis. Conclusion: Assessment of palpebral positioning using digital measures endorse that MRD is smaller in patients with palpebral ptosis and similar in congenital or acquired ptosis, whereas MSD and MED presented higher values in acquired ptosis.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O estudo objetivou verificar a influência da temperatura corporal nos parâmetros fisiológicos e nos períodos de indução e recuperação anestésicos de cascavéis (Crotalus durissus) anestesiadas com cetamina. Os animais foram previamente submetidos à hipotermia (HIPO) (<22°C) e normotermia (30°C) (NORMO) e anestesiados com 80mg/kg IM de cetamina. Foram avaliados os períodos de latência e recuperação da anestesia por meio do tônus de cabeça, tônus muscular e reflexo de endireitamento. Mensurou-se a frequência cardíaca (FC), tempo de apnéia e temperatura corporal em 0 min e 5, 10, 15, 30, 60, 90, 120 min e análise dos gases sanguíneos em 0 min, 30 e 60 min. Não houve diferença em relação ao período de latência entre os grupos. A recuperação dos animais em HIPO foi mais prolongada (5,5 horas) que em NORMO (3,5 horas). Obteve-se FC no grupo NORMO superior que no grupo HIPO. O tempo de apnéia manteve o mesmo padrão em ambos os grupos. em relação ao basal, tanto em HIPO quanto em NORMO o tempo de apnéia diminuiu acentuadamente entre 5 e 30 min. Observou-se acidose respiratória no grupo NORMO apenas em 0 min. O SvO2 elevou-se significativamente após 30 min, o mesmo ocorrendo com a PvO2. A PvCO2 diminuiu em ambos os grupos após 30 min. Evidenciou-se que a temperatura corporal influencia intrinsecamente o período de recuperação de cascavéis anestesiadas com cetamina.

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A acupuntura (AP) é uma técnica terapêutica empírica desenvolvida em uma cultura oriental e que utiliza pensamento mágico (linguagem pré-científica) em seu raciocínio. É uma terapia reflexa que utiliza a estimulação de pontos específicos do corpo com objetivo de atingir um efeito terapêutico ou homeostático. A AP preconiza que a saúde é dependente das funções psico-neuro-endócrinas, sob influência do código genético e de fatores extrínsecos como nutrição, hábitos de vida, clima, qualidade do ambiente, entre outros. O presente artigo faz uma breve revisão sobre a filosofia da AP, seus marcos históricos na China e no Ocidente, a história da AP veterinária no Brasil e no mundo. Também aborda a prática da AP, incluindo as formas de diagnóstico, a definição do protocolo de tratamento, os métodos de estimulação dos pontos, o agulhamento de animais, suas indicações, contra-indicações e reações adversas.

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To compare the effects of morphine (MOR), methadone (MET), butorphanol (BUT) and tramadol (TRA), in combination with acepromazine, on sedation, cardiorespiratory variables, body temperature and incidence of emesis in dogs.Prospective randomized, blinded, experimental trial.Six adult mixed-breed male dogs weighing 12.0 +/- 4.3 kg.Dogs received intravenous administration (IV) of acepromazine (0.05 mg kg(-1)) and 15 minutes later, one of four opioids was randomly administered IV in a cross-over design, with at least 1-week intervals. Dogs then received MOR 0.5 mg kg(-1); MET 0.5 mg kg(-1); BUT 0.15 mg kg(-1); or TRA 2.0 mg kg(-1). Indirect systolic arterial pressure (SAP), heart rate (HR), respiratory rate (f(R)), rectal temperature, pedal withdrawal reflex and sedation were evaluated at regular intervals for 90 minutes.Acepromazine administration decreased SAP, HR and temperature and produced mild sedation. All opioids further decreased temperature and MOR, BUT and TRA were associated with further decreases in HR. Tramadol decreased SAP whereas BUT decreased f(R) compared with values before opioid administration. Retching was observed in five of six dogs and vomiting occurred in one dog in MOR, but not in any dog in the remaining treatments. Sedation scores were greater in MET followed by MOR and BUT. Tramadol was associated with minor changes in sedation produced by acepromazine alone.When used with acepromazine, MET appears to provide better sedation than MOR, BUT and TRA. If vomiting is to be avoided, MET, BUT and TRA may be better options than MOR.

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Objective To evaluate the effects of methadone, administered alone or in combination with acepromazine or xylazine, on sedation and on physiologic values in dogs.Study design Randomized cross-over design.Animals Six adult healthy mixed-breed dogs weighing 13.5 +/- 4.9 kg.Methods Dogs were injected intramuscularly with physiologic saline (Control), or methadone (0.5mg kg(-1)) or acepromazine (0.1 mg kg(-1)) or xylazine (1.0 mg kg(-1)), or acepromazine (0.05 mg kg(-1)) plus methadone (0.5 mg kg(-1)) or xylazine (0.5 mg kg(-1)) plus methadone (0.5 mg kg(-1)) in a randomized cross-over design, with at least 1-week intervals. Sedation, pulse rate, indirect systolic arterial pressure, respiratory rate (RR), body temperature and pedal withdrawal reflex were evaluated before and at 15-minute intervals for 90 minutes after treatment.Results Sedation was greater in dogs receiving xylazine alone, xylazine plus methadone and acepromazine plus methadone. Peak sedative effect occurred within 30 minutes of treatment administration. Pulse rate was lower in dogs that received xylazine either alone or with methadone during most of the study. Systolic arterial pressure decreased only in dogs receiving acepromazine alone. When methadone was administered alone, RR was higher than in other treatments during most of the study and a high prevalence of panting was observed. In all treatments body temperature decreased, this effect being more pronounced in dogs receiving methadone alone or in combination with acepromazine. Pedal withdrawal reflex was absent in four dogs receiving methadone plus xylazine but not in any dog in the remaining treatments.Conclusions Methadone alone produces mild sedation and a high prevalence of panting. Greater sedation was achieved when methadone was used in combination with acepromazine or xylazine. The combination xylazine-methadone appears to result in better analgesia than xylazine administered alone. Both combinations of methadone/sedative were considered effective for premedication in dogs.

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Este trabalho objetivou avaliar, quantificar e padronizar a ocorrência dos reflexos espinhais em bezerros da raça holandesa de 15 a 90 dias de idade, os quais foram submetidos a avaliação nos membros torácicos (reflexo carpo radial, reflexo bicipital, reflexo tricipital e reflexo flexor) e nos membros pélvicos (reflexo patelar, reflexo tibial cranial, reflexo gastrocnêmio, reflexo ciático e reflexo flexor). Para quantificação da resposta involuntária frente ao reflexo realizado, padronizou-se a ausência do reflexo como sendo o algarismo 0; resposta discreta do reflexo como sendo l e a presença evidente da resposta como sendo 2. Os reflexos mais evidentes e constantes foram os reflexos flexor, carpo radial, patelar e tricipital. Os reflexos menos evidentes e menos freqüentes foram os reflexos tibial cranial, bicipital, gastrocnêmio e ciático.

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Nineteen bovines of both sexes aging from 5 month-old to 5 year-old, were referred to a veterinary hospital. Clinical signs were observed from 6 hours to 10 days before. Thirteen animals were found in permanent lateral recumbency, five showed motor incoordination, 15 were exclusively fed on grass pasture, three showed partial loss of visual acuity, 14 were blindness, 16 showed presence of normal pupillary reflex, 16 decreased ruminal motility, 14 decreased sensorium (depression, semicoma or coma) and eight showed opisthotonos. Dehydration and dried feces were directly related to the time of evolution of the process. All the animals were administrated vitamin B1 and showed a marked improvement of the clinical status within 4 to 48 hours after treatment. The longer the time between the onset of the clinical signs and treatment, the greater the delay for the restoration of the vision. The treatment was very effective for a rapid response of the animal.

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Fez-se a avaliação qualitativa e semiquantitativa dos reflexos espinhais em ovinos, utilizando-se 51 animais da raça Suffolk, machos e fêmeas, entre quatro e cinco meses de idade. Usaram-se os reflexos bilaterais dos membros torácicos, extensor carpo-radial, bicipital, tricipital e flexor, e pélvicos, isquiático, gastrocnêmio, patelar, tibial cranial e flexor, sendo zero indicativo de ausência de reflexo, 1= reflexo discreto e 2= reflexo evidente. Nos membros torácicos, as melhores respostas foram obtidas no flexor (99,0%) e no extensor carpo-radial (87,3%), seguidos de valores menos expressivos no bicipital (11,8%) e no tricipital (2,0%), com grau 2 de avaliação. Nos membros pélvicos, todos os ovinos produziram respostas em grau 2 para o reflexo flexor. Verificam-se também respostas evidentes nos reflexos patelar (98,0%) e isquiático (81,4%). Apenas 20,6% dos animais apresentaram resposta evidente ao reflexo tibial cranial, e nenhum ovino respondeu ao reflexo gastrocnêmio de forma satisfatória.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The excitatory amino acid L-glutamate injected into the nucleus of the solitary tract (NTS) in unanesthetized rats similar to peripheral chemoreceptor activation increases mean arterial pressure (MAP) and reduces heart rate. In this study, we investigated the effects of acute (I day) and chronic (15 days) electrolytic lesions of the preoptic-periventricular tissue surrounding the anteroventral third ventricle (AV3V region) on the pressor and bradycardic responses induced by injections of L-glutamate into the NTS or peripheral chemoreceptor activation in unanesthetized rats. Male Holtzman rats with sham or electrolytic AV3V lesions and a stainless steel cannula implanted into the NTS were used. Differently from the pressor responses (28 +/- 3 mm Hg) produced by injections into the NTS of sham-lesioned rats, L-glutamate (5 nmol/ 100 nl) injected into the NTS reduced MAP (-26 +/- 8 mm Hg) or produced no effect (2 7 turn Hg) in acute and chronic AV3V-lesioned rats, respectively. The bradycardia to L-glutamate into the NTS and the cardiovascular responses to chemoreflex activation with intravenous potassium cyanide or to baroreflex activation with intravenous phenylephrine or sodium nitroprusside were not modified by AV3V lesions. The results show that the integrity of the AV3V region is essential for the pressor responses to L-glutamate into the NTS but not for the pressor responses to chemoreflex activation, suggesting dissociation between the central mechanisms involved in these responses. (C) 2004 Elsevier B.V. All rights reserved.

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Peripheral chemoreflex activation with potassium cyanide (KCN) in awake rats or in the working heart-brainstem preparation (WHBP) produces: (a) a sympathoexcitatory/pressor response; (b) bradycardia; and (c) an increase in the frequency of breathing. Our main aim was to evaluate neurotransmitters involved in mediating the sympathoexcitatory component of the chemoreflex within the nucleus tractus solitarii (NTS). In previous studies in conscious rats, the reflex bradycardia, but not the pressor response, was reduced by antagonism of either ionotropic glutamate or purinergic P2 receptors within the NTS. In the present study we evaluated a possible dual role of both P2 and NMDA receptors in the NTS for processing the sympathoexcitatory component (pressor response) of the chemoreflex in awake rats as well as in the WHBP. Simultaneous blockade of ionotropic glutamate receptors and P2 receptors by sequential microinjections of kynurenic acid (KYN, 2 nmol (50 nl)(-1)) and pyridoxalphosphate-6-azophenyl-2',4'-disulphonate (PPADS, 0.25 nmol (50 nl)(-1)) into the commissural NTS in awake rats produced a significant reduction in both the pressor (+38 +/- 3 versus +8 +/- 3 mmHg) and bradycardic responses (-172 +/- 18 versus -16 +/- 13 beats min(-1); n = 13), but no significant changes in the tachypnoea measured using plethysmography (270 +/- 30 versus 240 +/- 21 cycles min(-1), n = 7) following chemoreflex activation in awake rats. Control microinjections of saline produced no significant changes in these reflex responses. In WHBP, microinjection of KYN (2 nmol (20 nl)(-1)) and PPADS (1.6 nmol (20 nl)(-1)) into the commissural NTS attenuated significantly both the increase in thoracic sympathetic activity (+52 +/- 2% versus +17 +/- 1%) and the bradycardic response (-151 +/- 17 versus -21 +/- 3 beats min(-1)) but produced no significant changes in the increase of the frequency of phrenic nerve discharge (+0.24 +/- 0.02+0.20 +/- 0.02 Hz). The data indicate that combined microinjections of PPADS and KYN into the commissural NTS in both awake rats and the WHBP are required to produce a significant reduction in the sympathoexcitatory response (pressor response) to peripheral chemoreflex activation. We conclude that glutamatergic and purinergic mechanisms are part of the complex neurotransmission system of the sympathoexcitatory component of the chemoreflex at the level of the commissural NTS.

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We investigated the effects of bilateral injections of the GABA receptor agonists muscimol (GABA A) and baclofen (GABA B) into the nucleus tractus solitarius (NTS) on the bradycardia and hypotension induced by iv serotonin injections (5-HT, 2 µg/rat) in awake male Holtzman rats. 5-HT was injected in rats with stainless steel cannulas implanted bilaterally in the NTS, before and 5, 15, and 60 min after bilateral injections of muscimol or baclofen into the NTS. The responses to 5-HT were tested before and after the injection of atropine methyl bromide. Muscimol (50 pmol/50 nl, N = 8) into the NTS increased basal mean arterial pressure (MAP) from 115 ± 4 to 144 ± 6 mmHg, did not change basal heart rate (HR) and reduced the bradycardia (-40 ± 14 and -73 ± 26 bpm at 5 and 15 min, respectively, vs -180 ± 20 bpm for the control) and hypotension (-11 ± 4 and -14 ± 4 mmHg, vs -40 ± 9 mmHg for the control) elicited by 5-HT. Baclofen (12.5 pmol/50 nl, N = 7) into the NTS also increased basal MAP, but did not change basal HR, bradycardia or hypotension in response to 5-HT injections. Atropine methyl bromide (1 mg/kg body weight) injected iv reduced the bradycardic and hypotensive responses to 5-HT injections. The stimulation of GABA A receptors in the NTS of awake rats elicits a significant increase in basal MAP and decreases the cardiac Bezold-Jarisch reflex responses to iv 5-HT injections.