Effects of catecholamines on volemic replacement with saline solution and the impact on heart rate variability in rabbits subjected to hemorrhage. A study by spectral analysis

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

Avaliação qualitativa do efeito de agentes de limpeza na camada de lama dentinária: estudo ultra-estrutural em microscopia eletrônica de varredura

Quando qualquer instrumento abrasiona ou corta a dentina, produz na superfície uma camada de lama dentinária ou smear layer. Dependendo do agente de união indicado em Odontologia adesiva, há a necessidade ou não da remoção da camada de lama da superfície dentinária. Com a finalidade de verificar a ação de diferentes substâncias para a limpeza dentinária, utilizamos 20 dentes pré-molares superiores íntegros, mantidos em soro fisiológico, nos quais as coroas foram seccionadas ao meio no sentido mésio-distal. Com instrumento diamantado, removeu-se o esmalte da porção vestibular e da porção lingual da coroa e, com uma broca carbide cilíndrica lisa nº 56, cortou-se aproximadamente 1 mm de dentina com alta rotação sob abundante refrigeração ar/água, para produzir a camada de lama dentinária. em seguida, essa superfície foi tratada com diferentes substâncias e lavada por 30 segundos com spray ar/água. No controle, foi simplesmente utilizado o spray ar/água. Os espécimes foram montados em suportes metálicos, preparados e visualizados no MEV-DSM 950 da Zeiss, em aumentos que variaram de 100 a 5.000 vezes. Os materiais que mais removeram a camada de lama foram, em ordem crescente: 1. spray ar/água; 2. fluoreto de sódio 2%; 3. associação alternada de Dakin/Tergensol; 4. água oxigenada 3%; 5. jateamento com óxido de alumínio 50 mm; 6. flúor acidulado 1,27%; 7. ácido poliacrílico 25%; 8. ácido fosfórico 10%.

Efeitos da associação da clonidina à bupivacaína hiperbárica na anestesia subaracnóidea alta

JUSTIFICATIVA E OBJETIVOS: Dados da literatura sugerem que a clonidina, um agonista alfa2-adrenérgico, em associação com a bupivacaína, na anestesia subaracnóidea alta pode aumentar a incidência de hipotensão e bradicardia. O objetivo desta pesquisa foi verificar o potencial sinergismo entre diferentes doses de clonidina, de 45 e 75 µg, e bupivacaína hiperbárica nas características e nos efeitos hemodinâmicos do bloqueio subaracnóideo alto (T4). MÉTODO: em estudo aleatório e duplamente encoberto, foram avaliados 60 pacientes estado físico ASA I, submetidos à cirurgia do abdômen inferior e membros inferiores. Os pacientes foram submetidos à anestesia subaracnóidea, com bupivacaína hiperbárica a 0,5% (17,5 mg - 3,5 ml) mais a associação das seguintes drogas: grupo Controle (n = 20) - solução fisiológica (0,5 ml); grupo Clon 45 (n = 20) - clonidina, na dose de 45 µg (0,3 ml), associada à solução fisiológica (0,2 ml); grupo Clon 75 (n = 20) - clonidina, na dose de 75 µg (0,5 ml). A cirurgia somente foi realizada quando o nível do dermátomo atingido pelo bloqueio analgésico foi de T4. RESULTADOS: A latência dos bloqueios analgésico e motor da anestesia subaracnóidea não diferiu significativamente entre os grupos (p > 0,05). Ambas as doses de clonidina prolongaram, de maneira significativa, a duração do bloqueio analgésico em T8 e do bloqueio motor grau 3 (determinado pela escala modificada de Bromage) (p < 0,05). A incidência de hipotensão arterial no per-operatório foi evidente somente no grupo Clon 75, em relação ao grupo Controle (p < 0,05), com o Clon 45 apresentando incidência intermediária entre os demais grupos. Não houve diferença significante entre os grupos em relação à bradicardia (p > 0,05). Ambas as doses de clonidina prolongaram a analgesia pós-operatória (intervalo de tempo decorrido entre o bloqueio subaracnóideo e a primeira solicitação de analgésico pelo paciente no pós-operatório) (p < 0,05). CONCLUSÕES: A clonidina na maior dose (75 µg) em associação com a bupivacaína durante anestesia subaracnóidea alta (T4) determina maior incidência de hipotensão arterial, mas prolonga o bloqueio analgésico e a analgesia pós-operatória igualmente como a menor dose (45 µg).

Avaliação laboratorial do uso de solução salina hipertônica e isotônica e de furosemida no tratamento da intoxicação por amônia em bovinos

Para testar a eficiência de vários tratamentos de intoxicação por amônia em bovinos, foram utilizados 25 garrotes que receberam cloreto de amônio por infusão intravenosa (iv) até o surgimento de quadro convulsivo. em seguida, os animais foram alocados em um dos cinco grupos experimentais e tratados da seguinte forma: 1) controle: infusão (iv) de 300mL de solução salina isotônica (SSI), no decorrer de 4h; 2) infusão (iv) de 30mL kg-1 PV de SSI no decorrer de 4h e administração de 4L de água intraruminal por meio de sonda esofágica (ASE); 3) mesmo tratamento do grupo 2 e dose única (iv) de furosemida (2mg kg-1 PV) (F); 4) injeção (iv) de 5mL kg-1 PV de solução salina hipertônica (SSH) 7,2% nos primeiros 30min, seguida de 20mL kg-1 PV de SSI e 4L de ASE; 5) mesmo tratamento do grupo 4 e dose única de F. No decorrer de 4h após a convulsão, foram determinados os teores plasmáticos de amônia e glicose, ureia, creatinina, potássio e sódio séricos, volume e gravidade específica da urina, e excreção urinária de amônio e ureia. No momento da convulsão, os teores de amônia plasmáticos foram muito altos e idênticos em todos os tratamentos, mas no 120°min, nos grupos tratados com associação de SSH+SSI+ASE (grupos 4 e 5), houve diminuição desse metabólito. O uso de furosemida (grupos 3 e 5) não aumentou a excreção total de urina. A terapia com associação de SSH+SSI+ASE aumentou ainda o volume urinário e a excreção percentual urinária de ureia e amônia durante o período crítico da 1ª hora de tratamento, mas o uso de SSI+ASE (grupos 2 e 3) teve resultados intermediários. A eficiência do tratamento com SSH+SSI+ASE ou SSI+ASE foi superior ao grupo controle. Embora com efeito menor que o observado com SSH+SSI+ASE, a SSI+ASE promoveu melhora no quadro clínico geral e, ao término do experimento, promoveu também uma adequada desintoxicação da amônia.

Autoradiographic investigation of effects of high-dose colchicine on dentinogenesis in rat incisors

Twelve female Wistar rats received 1.5 mg/kg of colchicine (CLC) intravenously. Control animals were similarly injected with isotonic saline solution. The animals were killed 5 h, 24 h, 3 days and 7 days after injection. Ninety minutes prior to sacrifice, all animals received an intraperitoneal injection of 3H-proline. Autoradiograms of maxillary incisors showed that CLC increased the retention of the labeled precursor in the odontoblasts. It was also shown that the odontoblasts in the different sectors of the rat incisor present different sensitivities to the CLC action.

Efeito da dose única de parecoxibe sobe a função, lesão celular e resposta inflamatória do rim de ratos submetidos à hemorragia aguda

Pós-graduação em Anestesiologia - FMB

Median preoptic nucleus mediates the cardiovascular recovery induced by hypertonic saline in hemorrhagic shock

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of furosemide treatment on the central and peripheral pressor responses to cholinergic and adrenergic agonists, angiotensin II, hypertonic solution and vasopressin

The present study was performed to investigate the effect of treatment with furosemide on the pressor response induced by intracerebroventricular (i.c.v.) injections of cholinergic (carbachol) and adrenergic (norepinephrine) agonists, angiotensin II (ANGII) and hypertonic saline (HS, 2 M NaCl). The changes induced by furosemide treatment on the pressor response to intravenous (i.v.) norepinephrine, ANGII and arginine vasopressin (AVP) were also studied. Rats with a stainless-steel cannula implanted into the lateral ventricle (LV) were used. Two injections of furosemide (30 mg/kg b.wt. each) were performed 12 and 1 h before the experiments. Treatment with furosemide reduced the pressor response induced by carbachol, norepinephrine and ANGII i.c.v., but no change was observed in the pressor response to i.c.v. 2 M NaCl. The pressor response to i.v. ANGII and norepinephrine, but not AVP, was also reduced after treatment with furosemide. These results show that the treatment with furosemide impairs the pressor responses induced by central or peripheral administration of adrenergic agonist or ANGII, as well as those induced by central cholinergic activation. The results suggest that the treatment with furosemide impairs central and peripheral pressor responses mediated by sympathetic activation and ANGII, but not those produced by AVP. © 1992.

Variations in peak nasal inspiratory flow among healthy students after using saline solutions

Nasal hygiene with saline solutions has been shown to relieve congestion, reduce the thickening of the mucus and keep nasal cavity clean and moist. Evaluating whether saline solutions improve nasal inspiratory flow among healthy children. Students between 8 and 11 years of age underwent 6 procedures with saline solutions at different concentrations. The peak nasal inspiratory flow was measured before and 30min after each procedure. Statistical analysis was performed by means of t test, analysis of variance, and Tukey's test, considering p<0.05. We evaluated 124 children at all stages. There were differences on the way a same concentration was used. There was no difference between 0.9% saline solution and 3% saline solution by using a syringe. The 3% saline solution had higher averages of peak nasal inspiratory flow, but it was not significantly higher than the 0.9% saline solution. It is important to offer various options to patients.

Occurrence of Cryptosporidium (Apicomplexa, Cryptosporidiidae) in Crotalus durissus terrificus (Serpentes, Viperidae) in Brazil

The objective of the present study was to investigate the prevalence of Cryptosporidium (Apicomplexa, Cryptosporidiidae) in the snake Crotalus durissus terrificus (Serpentes, Viperidae). Fifty animals were evaluated for the presence of oocysts of Cryptosporidium sp. at the time of arrival and 30 and 60 days later. Intestinal washings with saline solution (1% body weight), fecal samples, and organ scrapings were collected during the study. Oocysts were concentrated by an ether-phosphate-buffered saline sedimentation technique and then separated by a density gradient centrifugation technique. Smears were made with the sediment and submitted to modified acid-fast and auramine-rhodamine staining. Cryptosporidium-positive smears were used as controls for the experimental findings. The overall prevalence of Cryptosporidium sp. oocysts was 14%. Among the positive snakes, oocysts were detected only in the intestinal washing in two specimens, only in the feces in four specimens, and in both materials at least once in one specimen. The positive snakes were predominantly from Santa Maria da Serra city State of São Paulo (57.1%). We also observed that all of the examinations that presented positive results were obtained at least 27 days after the capture of the animals.

Pre-emptive epidural ketamine or S(+)-ketamine in post-incisional pain in dogs: A comparative study

Objective-To compare the pre-emptive analgesic effects of epidural ketamine or S(+)-ketamine on post-incisional hyperalgesia.Study Design-Prospective randomized study.Animals-Twenty-four mongrel dogs (1-5 years, weighing 11.9 +/- 1.8 kg).Methods-Dogs were anesthetized with propofol (5 mg/kg intravenously) and a lumbosacral epidural catheter was placed. Dogs were randomly allocated to 3 groups, each with 8 dogs. The control group (CG) was administered saline solution (0.3 mL/kg); the ketamine group (KG) ketamine (0.6 mg/kg); and the S(+)-ketamine group (SG) S(+)-ketamine (0.6 mg/kg). The final volume was adjusted to 0.3 mL/kg in all groups. Five minutes after the epidural injection a surgical incision was made in the common pad of the right hind limb and was immediately closed with simple interrupted nylon suture. Respiratory (RR) and heart (HR) rates, rectal temperature (7, sedation (S), lameness score, and mechanical nociceptive threshold by von Frey filaments were evaluated before the propofol anesthesia and at 15, 30, 45, 60, 75, and 90 minutes and then at 2, 4, 6, 8, 12, and 24 hours after epidural injection.Results-There were no differences in RR, HR, T, or S between groups. Motor blockade of the hind limbs was observed during 20 +/- 3.6 minutes in KG and during 30.6 +/- 7.5 minutes in SG (mean SD). Mechanical force applied to obtain an aversive response was higher from 45 minutes to 12 hours in KG and from 60 to 90 minutes in SG, when compared with CG.Conclusions-Pre-emptive epidural ketamine induced no alterations in RR and FIR, and reduced post-incisional hyperalgesia for a longer time than did S(+) ketamine.Clinical Relevance-Although anesthetic and analgesic potency of S(+) ketamine is twice that of ketamine, the racemic form is seemingly better for post-incisional hyperalgesia. (C) Copyright 2004 by the American College of Veterinary Surgeons.

Determination of the highest no-effect dose (HNED) and of the elimination pattern for cocaine in horses

Cocaine is one of the most widespread illegal stimulants utilized by the human population throughout the world. The aim of this study was to establish the highest no-effect dose (HNED) of cocaine on the spontaneous locomotor activity (SLA) of horses in a behavior chamber, and thereby to determine the maximal acceptable threshold of the urinary drug concentration in horses. Twelve English thoroughbred mares received 0.02, 0.03, 0.04, 0.08 or 0.12 mg kg(-1) cocaine i.v. or saline solution (control). It was noted that doses above 0.04 mg kg(-1) induced a significant increase in SLA (P < 0.05, Tukey's test). No significant increase in SLA was seen in the mares that received 0.03 mg kg(-1), but the animals showed important behavioral changes that did not occur after the 0.02 mg kg(-1) dose. It was concluded that the HNED of cocaine for horses in a behavior chamber is 0.02 mg kg(-1). After injection of this dose in five horses, urine samples were collected at predetermined intervals through vesical catheterization. The concentrations of cocaine, norcocaine, benzoylecgonine and ecgonine methyl ester were quantified by liquid chromatography/electrospray ionization tandem mass spectrometry. Cocaine and norcocaine concentrations remained consistently below the level of detection. Benzoylecgonine reached a mean (+/- SEM) maximum concentration of 531.9 +/- 168.7 ng ml(-1) after 4 h, whereas ecgonine methyl ester peaked 2 h after injection at a concentration of 97.2 +/- 26.5 ng ml(-1). The maximum admissible concentration for cocaine and/or metabolites in the urine of horses is difficult to establish unequivocally because of the substantial individual variation in the drug elimination pattern observed in horses, which can be inferred by the large standard error of the means obtained. Copyright (C) 2002 John Wiley Sons, Ltd.

Effects of levomepromazine and different desflurane concentrations upon electrocardiographic variables in dogs

Objectives To investigate the effects of levomepromazine and different desflurane concentrations upon electrocardiographic variables.Animals Twenty adult mongrel dogs of both sexes weighing 6-28 kg.Methods Dogs were divided into two groups of 10 animals. Group I received 1 mg kg(-1) lV of levomepromazine and 15 minutes later anesthesia was induced with propofol (3 mg kg(-1) IV). Desflurane end-tidal concentration was set at 1.6 MAC. After 30 minutes at this concentration, measurements were taken and the end-tidal concentration was reduced to 1.4 MAC. Thereafter, it was reduced to 1.2 and then 1.0 MAC at 1.5-minute intervals. The same procedure was followed for group 2, except that levomepromazine was replaced with 0.2 mL kg(-1) of 0.9% saline solution and more propofol was needed for induction (7 mg kg(-1)). The animals' body temperature was maintained between 38.3 and 39 degreesC using a heating pad. The electrocardiographic tracing was obtained from lead II throughout the experimental period. The measurements were taken immediately before the administration of levomepromazine or placebo (T-1), 15 minutes after pre-medication (T-2) and 30 minutes after the establishment of 1.6 MAC (T-3)The other measurements were made at the concentrations of 1.4, 1.2, and 1.0 MAC, respectively (T4-6). The numerical data were submitted to analysis of variance plus F-test (p < 0.05).Results the dogs that received levomepromazine had a decrease in heart rate. However, in both groups it increased with desflurane administration. Levomepromazine, in association with desflurane, did not induce significant electrocardiographic changes, and all mean values (except P-wave duration) were within the reference range for this species.Conclusions and clinical relevance This study documented that levomepromazine, in association with desflurane, does not induce significant changes in electrocardiographic variables, suggesting that this drug combination has minimal effect on myocardial conduction.

Efeitos cardiorrespiratórios da buprenorfina em cães anestesiados pelo desfluorano

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