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General Anesthetic (general + anesthetic)
Selected AbstractsA succession of anesthetic endpoints in the Drosophila brainDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2006Bruno van Swinderen Abstract General anesthetics abolish behavioral responsiveness in all animals, and in humans this is accompanied by loss of consciousness. Whether similar target mechanisms and behavioral endpoints exist across species remains controversial, although model organisms have been successfully used to study mechanisms of anesthesia. In Drosophila, a number of key mutants have been characterized as hypersensitive or resistant to general anesthetics by behavioral assays. In order to investigate general anesthesia in the Drosophila brain, local field potential (LFP) recordings were made during incremental exposures to isoflurane in wild-type and mutant flies. As in higher animals, general anesthesia in flies was found to involve a succession of distinct endpoints. At low doses, isoflurane uncoupled brain activity from ongoing movement, followed by a sudden attenuation in neural correlates of perception. Average LFP activity in the brain was more gradually attenuated with higher doses, followed by loss of movement behavior. Among mutants, a strong correspondence was found between behavioral and LFP sensitivities, thereby suggesting that LFP phenotypes are proximal to the anesthetic's mechanism of action. Finally, genetic and pharmacological analysis revealed that anesthetic sensitivities in the fly brain are, like other arousal states, influenced by dopaminergic activity. These results suggest that volatile anesthetics such as isoflurane may target the same processes that sustain wakefulness and attention in the brain. LFP correlates of general anesthesia in Drosophila provide a powerful new approach to uncovering the nature of these processes. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1195,1211, 2006 [source] Differential effects of sevoflurane and propofol anesthesia on left ventricular,arterial coupling in dogsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2010Y. L. J. M. DERYCK Background: General anesthetics interfere with arterial and ventricular mechanical properties, often altering left ventricular,arterial (LVA) coupling. We hypothesized that sevoflurane and propofol alter LVA coupling by different effects on arterial and ventricular properties. Methods: Experiments were conducted in six anesthetized open-chest dogs for the measurement of left ventricular pressure and aortic pressure and flow. Measurements were performed during anesthesia with 0.5, 1.0 and 1.5 minimum alveolar concentration sevoflurane and 12, 24 and 36 mg/kg/h propofol. LVA coupling was assessed as the ratio of ventricular end-systolic elastance (Ees, measuring ventricular contractility) to effective arterial elastance (Ea, measuring ventricular afterload). The steady component of afterload, arterial tone, was assessed by systemic vascular resistance and arterial pressure,flow curves. The pulsatile component of afterload was assessed by aortic impedance and compliance. Results: Sevoflurane decreased aortic pressure and cardiac output more than propofol. Sevoflurane reduced arterial tone, increased arterial stiffness and did not affect wave reflections. It increased Ea, decreased Ees and reduced LVA coupling. Propofol reduced arterial tone, did not affect arterial stiffness and decreased wave reflections. It did not affect Ea, Ees or LVA coupling. Conclusions: Sevoflurane increased ventricular afterload and decreased ventricular performance, thereby altering LVA coupling. Propofol did not affect ventricular afterload or ventricular performance, thereby preserving LVA coupling. Thus, propofol preserves LVA coupling in dogs better, and might be a better choice for patients with compromised left ventricular function. [source] Glycine Receptors Contribute to Hypnosis Induced by EthanolALCOHOLISM, Issue 6 2009Jiang H. Ye Background:, Glycine is a major inhibitory neurotransmitter in the adult central nervous system (CNS), and its receptors (GlyRs) are well known for their effects in the spinal cord and the lower brainstem. Accumulating evidence indicates that GlyRs are more widely distributed in the CNS, including many supraspinal regions. Previous in vitro studies have demonstrated that ethanol potentiates the function of these brain GlyRs, yet the behavioral role of the brain GlyRs has not been well explored. Methods:, Experiments were conducted in rats. The loss of righting reflex (LORR) was used as a marker of the hypnotic state. We compared the LORR induced by systematic administration of ethanol and of ketamine in the absence and presence of the selective glycine receptor antagonist strychnine. Ketamine is a general anesthetic that does not affect GlyRs. Results:, Systemically administered (by intraperitoneal injection) ethanol and ketamine dose-dependently induced LORR in rats. Furthermore, systemically administered (by subcutaneous injection) strychnine dose-dependently reduced the percentage of rats exhibiting LORR induced by ethanol, increased the onset time, and decreased the duration of LORR. Strychnine had no effect, however, on the LORR induced by ketamine. Conclusions:, Given that hypnosis is caused by neuronal depression in upper brain areas, we therefore conclude that brain GlyRs contribute at least in part to the hypnosis induced by ethanol. [source] Ventilation induced pneumothorax following resolved empyemaPEDIATRIC PULMONOLOGY, Issue 1 2008A.G. Nyman MRCPCH Abstract We report a case of pneumothorax as a result of positive pressure ventilation in a child previously treated for empyema. Three months following discharge for successful treatment of empyema our patient received a general anesthetic for an elective MRI of the brain for investigation of nystagmus. During recovery from the anesthetic he developed respiratory distress and was found to have a loculated pneumothorax. We propose that pleural fragility in childhood empyema possibly persists even after clinical resolution and in this case for up to 3 months. The complication of pneumothorax should be considered in all patients receiving positive pressure ventilation following resolved empyema. Pediatr Pulmonol. 2008; 43:99,101. © 2007 Wiley-Liss, Inc. [source] Mothers without Companionship During Childbirth: An Analysis within the Millennium Cohort StudyBIRTH, Issue 4 2008Holly N. Essex MSc ABSTRACT: Background: Studies have highlighted the benefits of social support during labor but no studies focused on women who choose to be unaccompanied or who have no companion available at birth. Our goals were, first, to identify characteristics of women who are unaccompanied at birth and compare these to those who had support and, second, to establish whether or not being unaccompanied at birth is a risk marker for adverse maternal and infant health outcomes. Methods: The sample comprised 16,610 natural mother-infant pairs, excluding women with planned cesarean sections in the Millennium Cohort Study. Multivariable regression models were used to examine, first, sociodemographic, cultural, socioeconomic, and pregnancy characteristics in relation to being unaccompanied and, second, being unaccompanied at birth in relation to labor and delivery outcomes, maternal health and health-related behaviors, parenting, and infant health and development. Results: Mothers who were single (vs not single), multiparous (vs primiparous), of black or Pakistani ethnicity (vs white), from poor households (vs nonpoor), with low levels of education (vs high levels), and who did not attend antenatal classes (vs attenders) were at significantly higher risk of being unaccompanied at birth. Mothers unaccompanied at birth were more likely to have a preterm birth (vs term), an emergency cesarean section (vs spontaneous vaginal delivery) and spinal pain relief or a general anesthetic (vs no pain relief), a shorter labor, and lower satisfaction with life (vs high satisfaction) at 9 months postpartum. Their infants had significantly lower birthweight and were at higher risk of delayed gross motor development (vs normal development). Conclusions: Being unaccompanied at birth may be a useful marker of high-risk mothers and infants in need of additional support in the postpartum period and beyond. (BIRTH 35:4 December 2008) [source] A succession of anesthetic endpoints in the Drosophila brainDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2006Bruno van Swinderen Abstract General anesthetics abolish behavioral responsiveness in all animals, and in humans this is accompanied by loss of consciousness. Whether similar target mechanisms and behavioral endpoints exist across species remains controversial, although model organisms have been successfully used to study mechanisms of anesthesia. In Drosophila, a number of key mutants have been characterized as hypersensitive or resistant to general anesthetics by behavioral assays. In order to investigate general anesthesia in the Drosophila brain, local field potential (LFP) recordings were made during incremental exposures to isoflurane in wild-type and mutant flies. As in higher animals, general anesthesia in flies was found to involve a succession of distinct endpoints. At low doses, isoflurane uncoupled brain activity from ongoing movement, followed by a sudden attenuation in neural correlates of perception. Average LFP activity in the brain was more gradually attenuated with higher doses, followed by loss of movement behavior. Among mutants, a strong correspondence was found between behavioral and LFP sensitivities, thereby suggesting that LFP phenotypes are proximal to the anesthetic's mechanism of action. Finally, genetic and pharmacological analysis revealed that anesthetic sensitivities in the fly brain are, like other arousal states, influenced by dopaminergic activity. These results suggest that volatile anesthetics such as isoflurane may target the same processes that sustain wakefulness and attention in the brain. LFP correlates of general anesthesia in Drosophila provide a powerful new approach to uncovering the nature of these processes. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1195,1211, 2006 [source] GABAA receptor associated proteins: a key factor regulating GABAA receptor functionJOURNAL OF NEUROCHEMISTRY, Issue 2 2007Zi-Wei Chen Abstract ,-Aminobutyric acid (GABA), an important inhibitory neurotransmitter in both vertebrates and invertebrates, acts on GABA receptors that are ubiquitously expressed in the CNS. GABAA receptors also represent a major site of action of clinically relevant drugs, such as benzodiazepines, barbiturates, ethanol, and general anesthetics. It has been shown that the intracellular M3-M4 loop of GABAA receptors plays an important role in regulating GABAA receptor function. Therefore, studies of the function of receptor intracellular loop associated proteins become important for understanding mechanisms of regulating receptor activity. Recently, several labs have used the yeast two-hybrid assay to identify proteins interacting with GABAA receptors, for example, the interaction of GABAA receptor associated protein (GABARAP) and Golgi-specific DHHC zinc finger protein (GODZ) with , subunits, PRIP, phospholipase C-related, catalytically inactive proteins (PRIP-1) and (PRIP-2) with GABARAP and receptor ,2 and , subunits, Plic-1 with some , and , subunits, radixin with the ,5 subunit, HAP1 with the ,1 subunit, GABAA receptor interacting factor-1 (GRIF-1) with the ,2 subunit, and brefeldin A-inhibited GDP/GTP exchange factor 2 (BIG2) with the ,3 subunit. These proteins have been shown to play important roles in modulating the activities of GABAA receptors ranging from enhancing trafficking, to stabilizing surface and internalized receptors, to regulating modification of GABAA receptors. This article reviews the current studies of GABAA receptor intracellular loop-associated proteins. [source] Malignant Tumors of the Maxilla: Virtual Planning and Real-Time Rehabilitation with Custom-Made R-zygoma Fixtures and Carbon,Graphite Fiber-Reinforced Polymer ProsthesisCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2008Karl Ekstrand LDS ABSTRACT Background: Oral cancer is a mutilating disease. Because of the expanding application of computer technology in medicine, new methods are constantly evolving. This project leads into a new technology in maxillofacial reconstructive therapy using a redesigned zygoma fixture. Purpose: Previous development experiences showed that the procedure was time-consuming and painful for the patients. Frequent episodes of sedation or general anesthetics were required and the rehabilitation is costly. The aim of our new treatment goal was to allow the patients to wake up after tumor surgery with a functional rehabilitation in place. Materials and Methods: Stereolithographic models were introduced to produce a model from the three-dimensional computed tomography (CT). A guide with the proposed resection was fabricated, and the real-time maxillectomy was performed. From the postoperative CT, a second stereolithographic model was manufactured and in addition, a stent for the optimal position of the implants. Customized zygoma implants were installed (R-zygoma, Integration AB, Göteborg, Sweden). A fixed construction was fabricated by using a new material based on poly(methylacrylate) reinforced with carbon/graphite fibers and attached to the implants. On the same master cast, a separate obturator was fabricated in permanent soft silicon. Results: The result of this project showed that it was possible to create a virtual plan preoperatively to apply during surgery in order for the patient to wake up functionally rehabilitated. Conclusion: From a quality-of-life perspective, it is an advantage to be rehabilitated fast. By using new computer technology, pain and discomfort are less and the total rehabilitation is faster, which in turn reduces days in hospital and thereby total costs. [source] | |||||||||||||