Contamination of equipment and surfaces in the operating room anesthesia workspace: a cross-sectional study.

Background: Contamination of the breathing circuit and medication preparation surface of an anesthesia machine can increase the risk of cross-infection.

Objective: To evaluate the contamination of the anesthetic medication preparation surface, respiratory circuits, and devices used in general anesthesia with assisted mechanical ventilation.

Design And Setting: Cross-sectional, quantitative study conducted at the surgical center of a philanthropic hospital, of medium complexity located in the municipality of Três Lagoas, in the eastern region of the State of Mato Grosso do Sul.

Broad Diversity of Fungi in Hospital Water.

Introduction: Some studies have reported the occurrence of microorganisms isolated from water. Considering these microorganisms, fungi are known to occur ubiquitously in the environment, including water, and some are pathogenic and may cause health problems, especially in immunocompromised individuals. The aim of this study was to identify fungi in hospital water samples and to correlate their presence with the concentration of free residual chlorine.

Modification of the natural progression of epileptogenesis by means of biperiden in the pilocarpine model of epilepsy.

Brain injuries are often associated with the later development of epilepsy. Evidence suggests that morphological and functional changes occur in the remaining neural tissue during a silent (or latent) period in which no seizures are expressed. It is believed that this silent (reorganization) period may provide a therapeutic window for modifying the natural history of disease progression.

Structural and Functional Characterization of the Interaction of Snapin with the Dopamine Transporter: Differential Modulation of Psychostimulant Actions.

The importance of dopamine (DA) neurotransmission is emphasized by its direct implication in several neurological and psychiatric disorders. The DA transporter (DAT), target of psychostimulant drugs, is the key protein that regulates spatial and temporal activity of DA in the synaptic cleft via the rapid reuptake of DA into the presynaptic terminal. There is strong evidence suggesting that DAT-interacting proteins may have a role in its function and regulation.

Role of adenosine in the antiepileptic effects of deep brain stimulation.

Despite the effectiveness of anterior thalamic nucleus (AN) deep brain stimulation (DBS) for the treatment of epilepsy, mechanisms responsible for the antiepileptic effects of this therapy remain elusive. As adenosine modulates neuronal excitability and seizure activity in animal models, we hypothesized that this nucleoside could be one of the substrates involved in the effects of AN DBS. We applied 5 days of stimulation to rats rendered chronically epileptic by pilocarpine injections and recorded epileptiform activity in hippocampal slices.

Prefrontal dopamine release and sensory-specific satiety altered in rats with neonatal ventral hippocampal lesions.

Rats with a neonatal ventral hippocampal lesion (NVHL) have been used to model certain features of schizophrenia because they display dopaminergic activity and behavioral alterations consistent with a dysfunctional prefrontal cortex after puberty. Microdialysis studies in normal rats demonstrated increased prefrontal dopamine release during the incentive phase of behavior in an experimental situation specifically designed to evidence this behavioral aspect: the so called "sensory-specific satiety" procedure. Our hypothesis is that if dopaminergic activity in the prefrontal cortex of NVHL rats differs from sham lesioned rats, the responsiveness to the aforementioned experimental situation should also be different.

Deep brain stimulation reverses anhedonic-like behavior in a chronic model of depression: role of serotonin and brain derived neurotrophic factor.

Background: Deep brain stimulation (DBS) is being investigated as a treatment for major depression, but its mechanisms of action are still unknown. We have studied the effects of ventromedial prefrontal cortex (vmPFC) stimulation in a chronic model of depression and assessed the involvement of the serotonergic system and brain derived neurotrophic factor (BDNF) in a DBS response.

Methods: Rats were subjected to chronic unpredictable mild stress during 4 weeks.

Conditioned fear is modulated by D2 receptor pathway connecting the ventral tegmental area and basolateral amygdala.

Excitation of the mesocorticolimbic pathway, originating from dopaminergic neurons in the ventral tegmental area (VTA), may be important for the development of exaggerated fear responding. Among the forebrain regions innervated by this pathway, the amygdala is an essential component of the neural circuitry of conditioned fear. The functional role of the dopaminergic pathway connecting the VTA to the basolateral amygdala (BLA) in fear and anxiety has received little attention.

Antidepressant-like effects of medial prefrontal cortex deep brain stimulation in rats.

Background: Subcallosal cingulate gyrus (SCG) deep brain stimulation (DBS) is being investigated as a treatment for major depression. We report on the effects of ventromedial prefrontal cortex (vmPFC) DBS in rats, focusing on possible mechanisms involved in an antidepressant-like response in the forced swim test (FST).

Methods: The outcome of vmPFC stimulation alone or combined with different types of lesions, including serotonin (5-HT) or norepineprhine (NE) depletion, was characterized in the FST.

Acoustic hypersensitivity in adult rats after neonatal ventral hippocampus lesions.

Rats with a bilateral neonatal ventral hippocampus lesion (NVHL) are used as models of neurobiological aspects of schizophrenia. In view of their decreased number of GABAergic interneurons, we hypothesized that they would show increased reactivity to acoustic stimuli. We systematically characterized the acoustic reactivity of NVHL rats and sham operated controls.

Involvement of median raphe nucleus 5-HT1A receptors in the regulation of generalized anxiety-related defensive behaviours in rats.

Changes in 5-HT1A receptor-mediated neurotransmission at the level of the median raphe nucleus (MRN) are reported to affect the expression of defensive responses that are associated with generalized anxiety disorder (e.g. inhibitory avoidance) but not with panic (e.

Gabaergic mechanisms of hypothalamic nuclei in the expression of conditioned fear.

The amygdala, the dorsal periaqueductal gray (dPAG), and the medial hypothalamus have long been recognized to be a neural system responsible for the generation and elaboration of unconditioned fear in the brain. It is also well known that this neural substrate is under a tonic inhibitory control exerted by GABA mechanisms. However, whereas there is a growing body of evidence to suggest that the amygdala and dPAG are also able to integrate conditioned fear, it is still unclear, however, how the distinct hypothalamic nuclei participate in fear conditioning.

Overshadowing in conditioned taste aversion or in conditioned emotional response after neonatal ventral hippocampal lesions in rats.

The neonatal hippocampus lesion thought to model schizophrenia should show the same modifications in behavioural tests as other models, especially pharmacological models, namely decreased latent inhibition, blocking and overshadowing. The present study is set out to evaluate overshadowing in order to complement our previous studies, which had tested latent inhibition. "Overshadowing" refers to the decreased conditioning that occurs when the to-be-conditioned stimulus is combined with another stimulus at the conditioning stage.

Rewarded associative and instrumental conditioning after neonatal ventral hippocampus lesions in rats.

Sprague Dawley rats were submitted to bilateral ventral hippocampus lesions 7 days after birth. This corresponds to the Lipska and Weinberger's procedure for modeling schizophrenia. The aim of the present work was to test the learning capacity of such rats with an associative Pavlovian and an instrumental learning paradigm, both methods using reward outcome (food, sucrose or polycose).

Alteration of conditioned emotional response and conditioned taste aversion after neonatal ventral hippocampus lesions in rats.

Sprague-Dawley rats were submitted to bilateral ventral hippocampus lesions 7 days after birth according to the Lipska and Weinberger's procedure for modeling schizophrenia. The aim of the present work was to better characterize their learning capacity. A double latent inhibition study was conducted using respectively conditioned taste aversion and conditioned emotional response.

5-HT2 receptor mechanisms of the dorsal periaqueductal gray in the conditioned and unconditioned fear in rats.

Rationale: It is well known that 5-HT(2) mechanisms modulate the defensive behavior produced by the stimulation of the dorsal periaqueductal gray (dPAG). However, in spite of the notion that past stressful experiences play a role in certain types of anxiety, only studies with the stimulation of the dPAG of rats without previous aversive experience have been conducted so far.

Objectives: We investigated the mediation of 5-HT(2) receptors of the dPAG in rats previously submitted to contextual fear conditioning (CFC).

5-HT2- and D1-mechanisms of the basolateral nucleus of the amygdala enhance conditioned fear and impair unconditioned fear.

The inferior colliculus (IC) is involved in processing of auditory information, but also integrates acoustic information of aversive nature. In fact, chemical stimulation of the IC with semicarbazide (SMC) - an inhibitor of the GABA synthesizing enzyme glutamic acid decarboxylase - has been found to cause defensive behavior in an open-field test and functions as an unconditioned stimulus in the place conditioned aversion test (PCA). A question has arisen regarding whether the basolateral nucleus of the amygdala (BLA) is involved in the acquisition of the aversive information ascending from the IC and whether dopaminergic and serotoninergic mechanisms of the BLA regulate this process.

Conditioned and unconditioned fear organized in the inferior colliculus are differentially sensitive to injections of muscimol into the basolateral nucleus of the amygdala.

Chemical stimulation of the inferior colliculus (IC) with semicarbazide--an inhibitor of the gamma aminobutyric acid synthesizing enzyme--functions as an unconditioned stimulus in the conditioned place aversion test (CPA), and electrolytic lesions of the basolateral amygdala (BLA) enhance the aversiveness of the IC stimulation. This study examined the effects of inactivation of the BLA with muscimol on the conditioned and unconditioned fear using semicarbazide injections into the IC of rats subjected to conditioned (CPA) or unconditioned (open field) fear tests. In both tests, the rats were injected with semicarbazide or saline into the IC and muscimol or saline into the BLA.

Pharmacological assessment of the freezing, antinociception, and exploratory behavior organized in the ventrolateral periaqueductal gray.

Opioid and serotonergic mechanisms of the ventrolateral periaqueductal gray (vlPAG) are recruited by conditioned freezing and antinociception. However, it is unclear whether freezing and antinociception induced by stimulation of the vlPAG are interrelated. To address this issue we looked at the effects of the opioid antagonist naltrexone, the 5-HT2 antagonist ketanserin, and the benzodiazepine agonist midazolam injected into the vlPAG on the freezing and antinociception induced by electrical stimulation of this region.

Behavioral effects of systemically administered MK-212 are prevented by ritanserin microinfusion into the basolateral amygdala of rats exposed to the elevated plus-maze.

Rationale: Although 5-HT2 receptors seem to play an important role in anxiety, results from numerous studies are still highly variable. Moreover, little is known about the behavioral effects of centrally administered 5-HT2 compounds in animal models of anxiety.

Objective: The current study was performed to: (1) further investigate the effects of 5-HT2 receptor activation in rats exposed to the elevated plus-maze (EPM) and the open-field arena, two widely used animal models for studying anxiety and locomotor activity; and (2) evaluate the involvement of the 5-HT2 receptors within the basolateral nucleus of the amygdala (BLA) in the modulation of such effects.

Increases in extracellular levels of 5-HT and dopamine in the basolateral, but not in the central, nucleus of amygdala induced by aversive stimulation of the inferior colliculus.

Consistent evidence has shown that dopamine release in the prefrontal cortex is increased by electrical stimulation of the inferior colliculus (IC) as unconditioned stimulus. Recent reports have also demonstrated that inactivation of the basolateral nucleus of the amygdala (BLA) with muscimol enhances the behavioural consequences of the aversive stimulation of the IC and reduces the dopamine release in the prefrontal cortex. Moreover, neurotoxic lesions of the BLA enhance whereas those of the central nucleus of the amygdala (CeA) reduce the aversiveness of the electrical stimulation of the IC.

Aversive stimulation of the inferior colliculus changes dopamine and serotonin extracellular levels in the frontal cortex: modulation by the basolateral nucleus of amygdala.

We have shown that stimulation of the neural substrates in the inferior colliculus (IC) causes a significant increase in the extracellular levels of dopamine (DA) in frontal cortex (FC). Also, it has been reported that the basolateral complex of the amygdala (BLA) serves as a filter for unconditioned and conditioned aversive information that ascend to higher structures from the brainstem. Linking these two kinds of information, this work examines whether inactivation of BLA interferes with the activation of cortical dopaminergic outputs produced by aversive stimulation of the IC.

Anxiolytic-like effects of median raphe nucleus lesion in the elevated T-maze.

The cell bodies of 5-HT containing neurons that innervate the limbic forebrain are mainly found in the dorsal raphe nucleus and in the median raphe nucleus (MRN). To assess the role of the median raphe nucleus in anxiety, rats bearing either electrolytic or 5-HT-selective neurotoxic lesion of the MRN were tested in the elevated T-maze. This apparatus consists of two opposed open arms perpendicular to one enclosed arm.

Fos-like immunoreactive neurons following electrical stimulation of the dorsal periaqueductal gray at freezing and escape thresholds.

Electrical stimulation of the dorsal regions of the periaqueductal gray (PAG) leads to defensive reactions characterized as freezing and escape responses. Until recently it was thought that this freezing behavior could be due to the recruitment of neural circuits in the ventrolateral periaqueductal gray (vlPAG), while escape would be mediated by other pathways. Nowadays, this view has been changing mainly because of evidence that freezing and escape behaviors thus elicited are not altered after lesions of the vlPAG.

Dual 5-HT mechanisms in basolateral and central nuclei of amygdala in the regulation of the defensive behavior induced by electrical stimulation of the inferior colliculus.

Regulatory mechanisms in the basolateral nucleus of the amygdala (BLA) serves as a filter for unconditioned and conditioned aversive information that ascend to higher structures from the brainstem whereas the central nucleus (CeA) is the main output for the resultant defense reaction. We have shown that neural substrates in the inferior colliculus are activated by threatening stimuli of acoustic nature and have important functional links with the amygdala. In this work, we examined the influence of lesions with 5,7-dihydroxytryptamine (5,7-DHT) of these nuclei of amygdala on the aversive responses induced by electrical stimulation of the inferior colliculus.