RESUMEN
BACKGROUND: Although recent guidelines for obstructive sleep apnea recommend early postoperative use of continuous positive airway pressure (CPAP) after endonasal skull base surgery, the time of initiation of CPAP is unclear. In this study we used a novel, previously validated cadaveric model to analyze the pressures delivered to the cranial base and evaluate the effectiveness of various repair techniques to withstand positive pressure. METHODS: Skull base defects were surgically created in 3 fresh human cadaver heads and repaired using 3 commonly used repair techniques: (1) Surgicel™ onlay; (2) dural substitute underlay with dural sealant onlay; and (3) dural substitute underlay with nasoseptal flap onlay with dural sealant. Pressure microsensors were placed in the sphenoid sinus and sella, both proximal and distal to the repair, respectively. The effectiveness of each repair technique against various CPAP pressure settings (5-20 cm H2 O) was analyzed. RESULTS: Approximately 79%-95% of positive pressure administered reached the sphenoid sinus. Sellar pressure levels varied significantly across the 3 repair techniques and were lowest after the third technique. "Breach" points (CPAP settings at which sellar repair was violated) were lowest for the first group. All 3 specimens showed a breach after the first repair technique. For the second repair technique, only a single breach was created in 1 specimen at 20 cm H2 O. No breaches were created in the third group. CONCLUSION: Different skull base repair techniques have varying ability to withstand CPAP. Both second and third repair techniques performed in a nearly similar fashion with regard to their ability to withstand positive pressure ventilation.
Asunto(s)
Presión de las Vías Aéreas Positiva Contínua , Procedimientos de Cirugía Plástica/métodos , Base del Cráneo/cirugía , Apnea Obstructiva del Sueño/cirugía , Cadáver , HumanosRESUMEN
BACKGROUND: Obstructive sleep apnea is a common respiratory disorder that can have negative effects on health and quality of life. Positive pressure therapy (CPAP) is the primary treatment. There is a lack of consensus on the risk of postoperative CPAP after endoscopic sinus or skull base surgery. We present a proof-of-concept cadaver model for measuring sinonasal pressure delivered by CPAP. METHODS: Three fresh cadaver heads were prepared by removing the calvaria and brain. Sphenoidotomies were made and sellar bone was removed. Pressure sensors were placed in the midnasal cavity, sphenoid sinus, and sella. CPAP was applied and the delivered pressure was recorded at increasing levels of positive pressure. Paired t tests and intraclass correlation coefficients were used to analyze results. RESULTS: Increases in positive pressure led to increased pressure recordings for all locations. Nasal cavity pressure was, on average, 81% of delivered CPAP. Pressure was highest in the sphenoid sinus. The effect of middle turbinate medialization on intrasphenoid pressure was not statistically significant in 2 heads. Intrasellar pressure was 80% of delivered CPAP with lateralized turbinates and 84% with medialized turbinates. Pressure recordings demonstrated excellent reliability for all locations. All heads developed non-sellar-based cranial base leaks at higher pressures. Cribriform region leaks were successfully sealed with DuraSeal®. CONCLUSION: Our proof-of-concept cadaver model represents a novel approach to measure pressures delivered to the nasal cavity and anterior skull base by CPAP. With further study, it may have broader clinical application to guide the safe postoperative use of CPAP in this population.
Asunto(s)
Presión de las Vías Aéreas Positiva Contínua/métodos , Senos Paranasales/fisiología , Apnea Obstructiva del Sueño/terapia , Anciano de 80 o más Años , Cadáver , Endoscopía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Anatómicos , Cavidad Nasal/cirugía , Senos Paranasales/cirugía , Guías de Práctica Clínica como Asunto , Reproducibilidad de los Resultados , RiesgoRESUMEN
The purpose of this study was to evaluate the effect of posterior septectomy size on surgical exposure and surgical freedom during the endoscopic transsphenoidal approach to the sella and parasellar region. Dissections were performed on 10 embalmed cadaver heads. Dissections started with wide bilateral sphenoidotomies, lateralization of middle turbinates, and a 5-mm posterior septectomy. The posterior septectomy was increased in 5-mm increments to a maximum of 35 mm, followed by bilateral middle turbinectomies. Surgical exposure was defined as the distance between the ipsilateral and contralateral limit of exposure as allowed by the posterior septum along a midsphenoid horizontal meridian. Surgical freedom was defined as the angle between the ipsilateral and contralateral limit. The mean baseline width of the posterior sphenoid sinus was 29.4 ± 3.7 mm. With a 5-mm septectomy, the mean width of surgical exposure was 21.1 ± 2.8 mm. The surgical exposure increased significantly with progressively larger posterior septectomy until a 20-mm posterior septectomy, after which no further increase in surgical exposure or freedom was obtained. Bilateral lateral opticocarotid recesses were accessible with a 15-mm posterior septectomy. The addition of bilateral middle turbinectomies did not significantly increase lateral exposure within the sphenoid sinus compared with middle turbinate lateralization.
RESUMEN
Alteration of the biological activity among neuronal components of the mesocorticolimbic (MCL) system has been implicated in the pathophysiology of drug abuse. Changes in the electrophysiological properties of neurons involved in the reward circuit seem to be of utmost importance in addiction. The hyperpolarization-activated cyclic nucleotide current, I h, is a prominent mixed cation current present in neurons. The biophysical properties of the I h and its potential modulatory role in cell excitability depend on the expression profile of the hyperpolarization-activated cyclic nucleotide gated channel (HCN) subunits. We investigated whether cocaine-induced behavioral sensitization, an animal model of drug addiction, elicits region-specific changes in the expression of the HCN2 channel's subunit in the MCL system. Tissue samples from the ventral tegmental area, prefrontal cortex, nucleus accumbens, and hippocampus were analyzed using Western blot. Our findings demonstrate that cocaine treatment induced a significant increase in the expression profile of the HCN2 subunit in both its glycosylated and non-glycosylated protein isoforms in all areas tested. The increase in the glycosylated isoform was only observed in the ventral tegmental area. Together, these data suggest that the observed changes in MCL excitability during cocaine addiction might be associated with alterations in the subunit composition of their HCN channels.
Asunto(s)
Encéfalo/efectos de los fármacos , Cocaína/farmacología , Expresión Génica/efectos de los fármacos , Canales Iónicos/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/fisiología , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización , Canales Iónicos/genética , Locomoción/efectos de los fármacos , Masculino , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Genomic recombination requires cutting, processing, and rejoining of DNA by endonucleases, polymerases, and ligases, among other factors. We have proposed that DNA recombination mechanisms may contribute to long-term memory (LTM) formation in the brain. Our previous studies with the nucleoside analog 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP), a known inhibitor of DNA ligases and polymerases, showed that this agent blocked consolidation of conditioned taste aversion without interfering with short-term memory (STM). However, because polymerases and ligases are also essential for DNA replication, it remained unclear whether the effects of this drug on consolidation were attributable to interference with DNA recombination or neurogenesis. Here we show, using C57BL/6 mice, that ara-CTP specifically blocks consolidation but not STM of context fear conditioning, a task previously shown not to require neurogenesis. The effects of a single systemic dose of cytosine arabinoside (ara-C) on LTM were evident as early as 6 h after training. In addition, although ara-C impaired LTM, it did not impair general locomotor activity nor induce brain neurotoxicity. Importantly, hippocampal, but not insular cortex, infusions of ara-C also blocked consolidation of context fear conditioning. Separate studies revealed that context fear conditioning training significantly induced nonhomologous DNA end joining activity indicative of DNA ligase-dependent recombination in hippocampal, but not cortex, protein extracts. Finally, unlike inhibition of protein synthesis, systemic ara-C did not block reconsolidation of context fear conditioning. Our results support the idea that DNA recombination is a process specific to consolidation that is not involved in the postreactivation editing of memories.
Asunto(s)
Reacción de Prevención/fisiología , Condicionamiento Psicológico/fisiología , Miedo/fisiología , Memoria/fisiología , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Recombinación Genética/fisiología , Animales , Trifosfato de Arabinofuranosil Citosina/farmacología , Reacción de Prevención/efectos de los fármacos , Condicionamiento Psicológico/efectos de los fármacos , ADN/biosíntesis , ADN/genética , ADN Ligasas/antagonistas & inhibidores , ADN Ligasas/metabolismo , Miedo/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/fisiopatología , Aprendizaje/efectos de los fármacos , Aprendizaje/fisiología , Potenciación a Largo Plazo/efectos de los fármacos , Potenciación a Largo Plazo/genética , Masculino , Memoria/efectos de los fármacos , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/genética , Trastornos de la Memoria/metabolismo , Ratones , Ratones Endogámicos C57BL , Recombinación Genética/efectos de los fármacosRESUMEN
Os autores apresentam um caso de Sindrome de Peutz-Jeghers atendido na Clinica de Colo-proctologia do Hospital Geral de Goiania - INAMPS, com quadro de choque hipovolemico devido a enterorragia. Apos tecerem comentarios a respeito das condutas propedeutica e terapeutica adotadas, discutem os principais aspectos clinicos da doença, levando em consideraçao a literatura existente sobre esta patologia.
Asunto(s)
Humanos , Masculino , Adulto , Síndrome de Peutz-JeghersRESUMEN
Os autores fazem uma análise retrospectiva de 204 pacientes operados de megacólon chagásico, com a técnica de Duhamel-Haddad; na Clínica de Colo-Proctologia do Hospital Geral de Goiânia - INAMPS, no período de janeiro de 1975 a dezembro de 1984. Cento e um pacientes eram do sexo masculino (49,5%) e cento e três do sexo feminino (50,5%). Analisam sua experiência no manuseio desta técnica, comparando a morbidade, a mortalidade e resultados funcionais com os obtidos por outros grupos. Levando em conta os resultados obtidos, consideram esta técnica relativamente fácil e que apresenta excelentes resultados