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.

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.

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.

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.

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.