Extracellular serotonin level in the basolateral nucleus of the amygdala and dorsal periaqueductal gray under unconditioned and conditioned fear states: An in vivo microdialysis study

Serotonin (5-HT) plays a key role in the neural circuitry mediating unconditioned and conditioned fear responses related to panic and generalized anxiety disorders. The basolateral nucleus of the amygdala (BLA) and the dorsal periaqueductal gray (dPAG) appear to be mainly involved in these conditions. The aim of this study was to measure the extracellular level of 5-HT and its metabolite 5-hydroxyindolacetic acid (5-HIAA) in the BLA and dPAG during unconditioned and conditioned fear states using in vivo microdialysis procedure. Thus, for the unconditioned fear test, animals were chemically stimulated in the dPAG with semicarbazide, an inhibitor of the gamma-aminobutyric acid-synthesizing enzyme glutamic acid decarboxylase. For the conditioned fear test, animals were subjected to a contextual conditioned fear paradigm using electrical footshock as the unconditioned stimulus. The results show that the 5-HT and 5-HIAA level in the BLA and dPAG did not change during unconditioned fear, whereas 5-HT concentration, but not 5-HIAA concentration, increased in these brain areas during conditioned fear. The present study showed that the 5-HT system was activated during conditioned fear, whereas it remained unchanged during unconditioned fear, supporting the hypothesis that 5-HT has distinct roles in conditioned and unconditioned fear (dual role of 5-HT in anxiety disorders). (C) 2009 Elsevier B.V. All rights reserved.

Selective involvement of GABAergic mechanisms of the dorsal periaqueductal gray and inferior colliculus on the memory of the contextual fear as assessed by the fear potentiated startle test

The inferior colliculus (IC) together with the dorsal periaqueductal gray (dPAG), the amygdala and the medial hypothalamus make part of the brain aversion system, which has mainly been related to the organization of unconditioned fear. However, the involvement of the IC and dPAG in the conditioned fear is still unclear. It is certain that GABA has a regulatory role on the aversive states generated and elaborated in these midbrain structures. In this study, we evaluated the effects of injections of the GABA-A receptor agonist muscimol (1.0 and 2.0 nmol/0.2 mu L) into the IC or dPAG on the freezing and fear-potentiated startle (FPS) responses of rats submitted to a context fear conditioning. Intra-IC injections of muscimol did not cause any significant effect on the FPS or conditioned freezing but enhanced the startle reflex in non-conditioned animals. In contrast, intra-dPAG injections of muscimol caused significant reduction in FPS and conditioned freezing without changing the startle reflex in non-conditioned animals. Thus, intra-dPAG injections of muscimol produced the expected inhibitory effects on the anxiety-related responses, the FPS and the freezing whereas these injections into the IC produced quite opposite effects suggesting that descending inhibitory pathways from the IC, probably mediated by GABA-A mechanisms, exert a regulatory role on the lower brainstem circuits responsible for the startle reflex. (C) 2008 Elsevier Inc. All rights reserved.

Offspring size effects in the marine environment: A field test for a colonial invertebrate

A central tenet of life-history theory is the presence of a trade-off between the size and number of offspring that a female can produce for a given clutch. A crucial assumption of this trade-off is that larger offspring perform better than smaller offspring. Despite the importance of this assumption empirical, field-based tests are rare, especially for marine organisms. We tested this assumption for the marine invertebrate, Diplosoma listerianum, a colonial ascidian that commonly occurs in temperate marine communities. Colonies that came from larger larvae had larger feeding structures than colonies that came from smaller larvae. Colonies that came from larger larvae also had higher survival and growth after 2 weeks in the field than colonies that came from smaller larvae. However, after 3 weeks in the field the colonies began to fragment and we could not detect an effect of larval size. We suggest that offspring size can have strong effects on the initial recruitment of D. listerianum but because of the tendency of this species to fragment, offspring size effects are less persistent in this species than in others.

On Reciprocal Illumination and Consilience in Biogeography

Biogeography deals with the combined analysis of the spatial and temporal components of the evolutionary process. To this purpose, biogeographical analysis should consider two extra steps: a reciprocal illumination step, and a consilience step. Even if the traditional challenges of biogeography were successfully handled, the obtained hypothesis is not necessarily meaningful in biogeographical terms--it needs continuous test in the light of external hypotheses. For this reason, a concept analogous to Hennig`s reciprocal illumination is valuable, as well as a sort of biogeographical consilience in Whewell`s sense. Firstly, through the search for different classes of evidence, information useful to improve the hypothesis can be accessed via reciprocal illumination. Following, a more general hypothesis would arise through a consilience process, when the hypothesis explains phenomena not contemplated during its construction, as the distribution of other taxa or the existence (or absence) of fossils. This procedure aims to evaluate the robustness of biogeographical hypotheses as scientific theories. Such theories are reliable descriptions of how life changes its form both in space and time, putting historical biogeography close to Croizat`s statement of evolution as a three dimensional phenomenon.

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). The associative paradigm comprised also a second learning test with reversed learning contingencies. The instrumental conditioning comprised an extinction test under outcome devaluation conditions. Neonatally lesioned rats, once adults (over 60 days of age), showed a conditioning deficit in the associative paradigm but not in the instrumental one. Lesioned rats remained able to adapt as readily as controls to the reversed learning contingency and were as sensitive as controls to the devaluation of outcome. Such observations indicate that the active access (instrumental learning) to a reward could have compensated for the deficit observed under the ""passive"" stimulus-reward associative learning condition. This feature is compared to the memory management impairments observed in clinical patients. (c) 2008 Elsevier B.V. All rights reserved.

Assessment of vocational guidance: The Berufsbilder test

The object of this study is to assess informative possibilities of some technical indicators of the Test of Photos of Professions (BBT - Berufsbilder test), a projective method to clarify professional inclination, proposed by Martin Achtnich. This psychological evaluation technique is composed of 96 photos of professionals, performing various types of activities. The test subject classifies the photos into three groups: positive (agreeable), negative (disagreeable) and indifferent (neutral). Among those chosen positively, five preferences are chosen and a story is developed that includes them, an activity that is requested two times during the Vocational Guidance process: in the beginning (or middle) and at the end of the intervention. In this study, 160 stories were created by 80 youths, between 15 and 20 years of age, in public and private schools in a mid-sized Brazilian city. The stories were compared in three analytical categories: protagonist, professional conflict and resolution. The results were submitted to Wilcoxon nonparametric statistical analysis (p < .05), significant and relevant indicators of resolution being found in the process of occupational choice. This technical resource was shown, from this empirical evidence, to be promising for use in evaluation of intervention processes of Vocational Guidance.

T-Shaped Microsuture: A New Suture Technique for Laryngeal Microsurgery

To describe a new suture technique for laryngeal microsurgery and to test its applicability in human cadaver larynges. The new technique was experimentally tested in freshly excised human larynges fixed to a larynx holder appropriate for the simulation of laryngeal microsurgery. A mucosal flap was created in the vocal fold for the fabrication of a pocket for subepithelial fat implantation, and the wound edges were then brought together and sutured using the proposed technique. The time necessary for suture was measured with a stopwatch for five successive sutures performed by one of the surgeons. The presence or absence of mucosal rupture was determined for five sutures performed by two surgeons, for a total of 10 sutures. The sutures were performed without the help of an assistant, with no laceration of the mucosa being observed in any of the attempts, and within a relatively short period of time even without previous training. The sutures performed permitted the implanted fat to remain stable under the mucosal flap. Conclusions: the new suture technique is an easy procedure, which can be performed by a single surgeon under microscopic vision, with a low risk of tissue rupture. The technique does not markedly prolong the duration of surgery and a single suture thread can be used for the fabrication of more than one stitch.

Selective Vagal Denervation of the Sinus and Atrioventricular Nodes, Guided by Vagal Reflexes Induced by High Frequency Stimulation, to Treat Refractory Neurally Mediated Syncope

Vagal Denervation and Neurally Mediated Syncope. A 15-year-old female patient presented with frequent episodes of vasovagal syncope refractory to non-pharmacological and pharmacological measures. Two tilt-table tests performed before and after conventional therapy were positive and reproduced the patient`s clinical symptoms. Selective vagal denervation, guided by HFS, was performed. Six radiofrequency pulses were applied on the left and right sides of the interatrial septum, abolishing vagal responses at these locations. Basal sinus node and Wenckebach cycle lengths changed significantly following ablation. A tilt test performed after denervation was negative and revealed autonomic tone modification. The patient reported significant improvement in quality of life and remained asymptomatic for 9 months after denervation. After this period, three episodes of NMS occurred during a 4-month interval and a tilt test performed 11 months after the procedure demonstrated vagal activity recovery. (J Cardiovasc Electrophysiol, Vol. 20, pp. 558-563, May 2009).

In vivo biological performance of a novel highly bioactive glass-ceramic (Biosilicate (R)): A biomechanical and histomorphometric study in rat tibial defects

This study aimed to investigate bone responses to a novel bioactive fully crystallized glass-ceramic of the quaternary system P(2)O(5)-Na(2)O-CaO-SiO(2) (Biosilicates (R)). Although a previous study demonstrated positive effects of Biosilicate (R) on in vitro bone-like matrix formation, its in vivo effect was not studied yet. Male Wistar rats (n = 40) with tibial defects were used. Four experimental groups were designed to compare this novel biomaterial with a gold standard bioactive material (Bioglass (R) 45S5), unfilled defects and intact controls. A three-point bending test was performed 20 days after the surgical procedure, as well as the histomorphometric analysis in two regions of interest: cortical bone and medullary canal where the particulate biomaterial was implanted. The biomechanical test revealed a significant increase in the maximum load at failure and stiffness in the Biosilicate group (R) (vs. control defects), whose values were similar to uninjured bones. There were no differences in the cortical bone parameters in groups with bone defects, but a great deal of woven bone was present surrounding Biosilicate (R) and Bioglass (R) 45S5 particulate. Although both bioactive materials supported significant higher bone formation; Biosilicate (R) was superior to Bioglass (R) 45S5 in some histomorphometric parameters (bone volume and number of osteoblasts). Regarding bone resorption, Biosilicate (R) group showed significant higher number of osteoclasts per unit of tissue area than defect and intact controls, despite of the non-significant difference in the osteoclastic surface as percentage of bone surface. This study reveals that the fully crystallized Biosilicate (R) has good bone-forming and bone-bonding properties. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 978: 139-147, 2011.

Laparoscopic extended cardiomyotomy in children: an effective procedure for the treatment of esophageal achalasia

Purpose: Achalasia of the esophagus is characterized by aperistalsis and incomplete relaxation of the lower esophageal sphincter in response to swallowing. The objective of the present study is to present the experience of a modified Heller myotomy via a laparoscopic approach for the treatment of children who had this condition. Methods: A retrospective review of medical records of all patients who underwent this procedure from 2000 to 2009 was performed. The procedure consisted of an extended esophagomyotomy beginning on the lower part of the lower esophageal sphincter and continuing 5 to 6 cm above on the lower third of the esophagus, and then extended 3 to 4 cm below to the stomach, associated with an anterior 180-degree hemi-fundoplication according to Dor`s technique. Results: Fifteen patients were included in the study. There were 8 female and 7 male patients. Mean operating time was 190 minutes with no intraoperative complications and 1 conversion to open surgery because of difficulty in dissecting an inflamed distal esophagus. In a mean follow-up period of 32.3 months, 2 patients had recurrence of mild dysphagia that disappeared spontaneously, and 1 required a single botulinum toxin injection with complete resolution of symptoms. Conclusion: We conclude that the laparoscopic extended Heller myotomy with Dor fundoplication is a safe and effective method for the treatment for achalasia in the pediatric population even in advanced cases. (C) 2010 Elsevier Inc. All rights reserved.

Transanal endorectal pull-through in children with Hirschsprung`s disease-technical refinements and comparison of results with the Duhamel procedure

Purpose: Transanal endorectal pull-through (TEPT) has drastically changed the treatment of Hirschsprung`s disease (HD). A short follow-up of children Submitted to TEPT reveals results that are similar to the classic transabdominal pull-through procedures. However, few reports compare the late results of TEPT with transabdominal pull-through procedures with respect to complication rates and the fecal continence. The aims of the present work are to describe some technical refinements that we introduced in the procedure and to compare the short and long-term outcome of TEPT with the outcomes of a group of patients with HD who previously underwent the Duhamel procedure. Methods: Thirty-five patients who underwent TEPT were prospectively studied and compared to a group of 29 patients who were treated with colostomy followed by a classical Duhamel pull-through. The main modifications introduced in the TEPT group were no preoperative colon preparation, operation conducted under general anesthesia in addition to regional sacral anesthesia, use of only one purse-string Suture in the rectal mucosa before transanal submucosal dissection, and no use of retractors and electrocautery during file submucosal dissection. Results: The most frequent early complications of TEPT group were perineal dermatitis (22.8%) and anastomotic strictures (8.6%). The comparison with patients who underwent Duhamel procedure revealed no difference in the incidence of preoperative enterocolitis, the patients of the TEPT group were younger at the time of diagnosis and of surgery, they had shorter operating times, and they began oral feeding more quickly after the operation. The incidence of wound infection was lower in the TEPT group. Moreover, the TEPT and Duhamel groups showed no difference in the incidences of mortality, postoperative partial continence, and total incontinence. Although the incidences of complete continence and postoperative enterocolitis were not different, a tendency to the increased incidence in the TEPT group was observed. Conclusions: This study further supports the technical advantages, the simplicity, and the decreased incidence of complications of a primary TEPT procedure when compared to a classical form of pull-through. Sonic technical refinements are described, and no preoperative colon preparation was necessary for the patients studied here. The results show that the long-term outcomes of the modified TEPT procedure are generally better than those obtained with classical approaches. Published by Elsevier Inc.

Urine is necessary to provoke bladder inflammation in protamine sulfate induced urothelial injury

Purpose: The bladder is normally impermeable to possible hostile environmental factors and toxic urinary wastes. Any disruption of the permeability barrier would permit the leakage of urine constituents into the underlying cells layers and subsequent inflammation. Protamine sulfate, which increases urothelial permeability, is used in experimental models of cystitis. We examined whether protamine sulfate alone could cause bladder inflammation or if the association of protamine sulfate and urine is needed for this condition. Materials and Methods: Female Wistar rats (Center for the Development of Experimental Models for Medicine and Biology, Federal University of Sao Paulo, Sao Paulo, Brazil) had the bladder catheterized and instilled with protamine sulfate (10 mg) or sterile saline for 30 minutes. To exclude urine other groups of rats underwent bilateral nephrectomy and the same procedure was used. One day after instillation the bladders were removed for histopathology. Edema and vascular congestion were graded from 0-none to 3-severe. Polymorphonuclear and mast cells were counted. The Kruskal-Wallis test was performed for statistical analysis. Results: Intravesical instillation of protamine sulfate in nonnephrectomized rats led to inflammation, in contrast to findings in rats instilled with saline. On the other hand, nephrectomized rats showed no inflammatory changes following the instillation of protamine sulfate or saline. The mast cell count was similar in all groups. Conclusions: Bladder inflammation in this experimental model of urothelial injury was not due to protamine sulfate alone. The association of protamine sulfate and urine was necessary to trigger the inflammatory cascade. Thus, urine indeed has an important role in the development of bladder inflammation in an environment of higher urothelial permeability.

Macroscopic test of quantum mechanics versus stochastic electrodynamics

We identify a test of quantum mechanics versus macroscopic local realism in the form of stochastic electrodynamics. The test uses the steady-state triple quadrature correlations of a parametric oscillator below threshold.