Regulation of contextual conditioning by the median raphe nucleus

The median raphe nucleus (MRN) has been suggested as the origin of a behavioral inhibition system that projects to the septum and hippocampus. Electrical stimulation of this mesencephalic area causes behavioral and autonomic manifestations characteristic of fear such as, freezing, defecation and micturition. In this study we extend these observations by analyzing the behavioral and autonomic responses of rats with lesions in the MRN submitted to a contextual conditioning paradigm. The animals underwent electrolytic or sham lesions of the median raphe nucleus. One day (acute) or 7 days (chronic) later they were tested in an experimental chamber where they received 10 foot-shocks (0.7 mA, 1 s with 20-s interval). The next day, sham and MRN-lesioned animals were tested again either in the same or in a different experimental chamber. During this, the duration of freezing, rearings, bouts of micturition and number of fecal boli were recorded. Sham-operated rats placed in the same chamber showed more freezing than rats exposed to a different context. This freezing behavior was clearly suppressed in rats with acute or chronic lesions in the MRN. MRN lesions also reduced the bouts of micturition and number of fecal boli. These rats showed a reduced number of rearings than sham-lesioned rats. This effect is probably the result of the displacement effect provoked by freezing since no significant differences in the number of rearings could be observed between these animals and the NMR-lesioned rats tested in an open field. This lesion produced higher horizontal locomotor activity in this test than the controls (sham-lesioned rats). These results point to the importance of the median raphe nucleus in the processing of fear conditioning with freezing being the most salient feature of it. Behavioral inhibition is also under control of MRN but its neural substrate seems to be dissociated from that of contextual fear. (C) 1998 Elsevier B.V. B.V.

Nitrous oxide production and potential denitrification in soils from riparian buffer strips: Influence of earthworms and plant litter

Vegetated riparian buffer strips have been established in Southern Quebec (Canada) in order to intercept nutrients such as nitrate (NO(3)(-)) and protect water quality near agricultural fields. Buffer strips may also favour denitrification through a combination of high soil moisture, NO(3)(-) and carbon supply, which could lead to the production of nitrous oxide (N(2)O), a greenhouse gas. Denitrification could be further amplified by the presence of earthworms, or by plant species that promote earthworm and bacterial activity in soils. Soils from four farms, comprising maize fields and adjacent buffer strips, were sampled in the fall of 2008. A total of six earthworm species were found, but average earthworm biomass did not differ between buffer strips and maize agroecoecosystems. Nitrate concentrations and net nitrification rates were higher in the maize fields than in the buffer strips: there was no difference in N(2)O production in soils collected from the two sampling locations. Potential denitrification, measured by acetylene inhibition, varied by two orders of magnitude, depending on experimental conditions: when amended with H(2)O or with H(2)O + NO3-, potential denitrification was higher (P < 0.05) in soils from buffer strips than from maize fields. Potential denitrification was highest in soils amended with H(2)O+glucose, or with H(2)O+ NO(3)(-) + glucose. Using microcosms, we tested the effect of litter-soil mixtures on earthworm growth, and the effect of earthworm-litter-soil mixtures on potential denitrification. Based on four categories of chemical assays, litters of woody species (oak, apple, Rhododendron) were generally of lower nutritional quality than litter from agronomic species (alfalfa, switchgrass, corn stover). Alfalfa litter had the most positive effect, whereas apple litter had the most negative effect, on earthworm growth. Potential denitrification was 2-4 times higher in earthworm-litter-soil mixtures than in plain soil. Litter treatments that included corn stover had lower potential denitrification than those that included alfalfa or switchgrass, whereas litter treatments that included oak had lower potential denitrification than those that included apple or Rhododendron. Results suggest that potential N(2)O emissions may be higher in riparian buffer strips than in adjacent maize fields, that N(2)O emissions in buffer strips may be amplified by comminuting earthworms, and that plant litters that reduce earthworm growth may not be best at mitigating N(2)O emissions. (c) 2010 Elsevier B.V. All rights reserved.

Pharmacological antagonism of Anchietia salutaris extracts on the contraction induced by prostaglandin D2 and U46619 in guinea-pig lung parenchymal strips

Anchietia salutaris tea is traditionally used in Brazil to treat allergies, suggesting it contains compounds with antagonistic activity on the allergic mediators. We have evaluated extracts and semi-purified fractions of Anchietia salutaris as a source of compounds having this type of antagonism on the contraction induced in guinea-pig lung parenchymal strips and on platelet aggregation and shape change. After 10 min pre-incubation dichloromethane extracts containing 30 or 100 μg mL-1 inhibited the contraction induced by prostaglandin D2 (PGD2) in guinea-pig lung parenchymal strips with dose ratios (DR) of 0.76 ± 0.14 and 0.93 ± 0.19, respectively; the amount of inhibition depended both on the concentration and on the time of preincubation (DR after 30 min pre-incubation was 1.21 ± 0.51). The dichloromethane extract and its semi-purified fractions also inhibited the contractions induced by U46619, a more potent, stable, synthetic agonist of thromboxane A2 (TxA2) prostanoid (TP) receptors, the receptors acted upon by PGD2 to produce lung contractions. The dichloromethane extract did not inhibit the lung parenchymal contractions induced by histamine, leukotriene D4 (LTD4) or platelet-activating factor (PAF). Platelet aggregation induced by U46619, adenosine 5'-diphosphate (ADP) or PAF was not inhibited by the dichloromethane extract. Indeed, the extract potentiated platelet aggregation induced by low concentrations of these agonists and also potentiated the shape change induced by U46619. These results imply that the dichloromethane extract of Anchietia salutaris and its semipurified fractions contain an active principle that competitively inhibits TxA2 TP receptors, the stimulation of which causes lung parenchymal contraction. The inhibition seems to be selective for this receptor subtype, because the extract fails to inhibit platelet aggregation or shape change. This provides additional support of earlier reports suggesting the occurrence of TP receptor subtypes.

Effect of electrolytic lesion of the median raphe nucleus on behavioral and physiological measures of stress.

The effect of electrolytic lesion of the median raphe nucleus was measured on behavioral and physiological parameters related to stress 24 h after the lesion. In of the elevated plus-maze the lesion decreased the percentage of open arm entries and tended to shorten the time spent on the open arms indicating an increase in anxiety. In contrast, the lesion markedly increased the time spent in the bright (aversive) compartment of the light-dark box and decrease in attempts to cross from the dark toward the bright compartment, an anxiolyic effect. With the exception of plasma prolactin level, which was lowered by the lesion, the physiological measures used in the present study indicate that the lesioned animals are under stress. Thus, death rate and weight loss after the surgery were higher in lesioned than in control animals. In addition, lesioned animals showed higher plasma corticosterone levels, a high incidence of gastric ulcers in the fundus and a depressed immune response to the mitogen concavaline A. These results highlight the importance of the median raphe nucleus in the regulation of stress and anxiety. They also show that behavioral and physiological measures of stress may be dissociated.

Ulnar-to-median nerve anastomosis in the forearm. Review and report of 2 new cases

The ulnar-to-median nerve anastomosis in the forearm is a very rare occurrence, not mentioned in many anatomical text books. We found only 4 cases cited in medical literature. Here we describe 2 new cases, for which diagnosis was suspected when the compound muscle action potential of the abductor pollicis brevis muscle (APB), obtained by maximal stimulation of the median nerve at the elbow, was lower than that obtained at the wrist. The diagnosis was confirmed by stimulation of the ulnar nerve at the elbow, which evoked a compound muscle action potential of the APB with a clear negative initial deflection without volume-conducted potential.

Measurement of the underlying event activity in pp collisions at √s = 0.9 and 7 TeV with the novel jet-area/median approach

The first measurement of the charged component of the underlying event using the novel jet-area/median approach is presented for proton-proton collisions at centre-of-mass energies of 0.9 and 7 TeV. The data were recorded in 2010 with the CMS experiment at the LHC. A new observable, sensitive to soft particle production, is introduced and investigated inclusively and as a function of the event scale defined by the transverse momentum of the leading jet. Various phenomenological models are compared to data, with and without corrections for detector effects. None of the examined models describe the data satisfactorily. © 2012 SISSA.

Median ages at stages of sexual maturity and excess weight in school children

Background: We aimed to estimate the median ages at specific stages of sexual maturity stratified by excess weight in boys and girls.Materials and method: This was a cross-sectional study made in 2007 in Florianopolis, Brazil, with 2,339 schoolchildren between 8 to 14 years of age (1,107 boys) selected at random in two steps (by region and type of school). The schoolchildren were divided into: i) those with excess weight and ii) those without excess weight, according to the WHO 2007 cut-off points for gender and age. Sexual maturity was self-evaluated by the subjects according to the Tanner sexual development stages, and utilizing median ages for the genitalia, breasts, and pubic hair stages.Results: In the boys with excess weight, precocity was observed in the stages 4 for genitals and pubic hair and 2 for pubic hair, with the values for excess and normal weight. The median ages at the beginning of puberty (stage 2-sexual development) for boys and girls in Florianopolis were 10.8 and 10.3 years, respectively.Conclusion: Excess weight is associated with lower median ages in the sexual maturity stages in boys and girls and that it should be taken into account when evaluating sexual maturity in children and adolescents.

Involvement of the median preoptic nucleus in blood pressure control

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The median raphe nucleus in anxiety revisited

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thickness and marking quality of different occlusal contact registration strips

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Median preoptic nucleus mediates the cardiovascular recovery induced by hypertonic saline in hemorrhagic shock

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of lithium on behavioral disinhibition induced by electrolytic lesion of the median raphe nucleus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Median lethal concentration of formaldehyde and its genotoxic potential in bullfrog tadpoles (Lithobates catesbeianus)

In order to avoid that contaminated frog farms animals escaping in the environment and become potential vector of emergent diseases, studies with disinfection protocol are strictly necessary. The formaldehyde is one of the compounds tested in fungal disinfection protocols and also used in aquaculture. This study aimed to determine the median lethal concentration (LC50-96h) of formaldehyde in bullfrog tadpoles and to evaluate the possible genotoxic effects in acute exposition. Accordingly, the animals were exposed to formaldehyde in the concentrations of 6, 9, 12, 15, and 18 mg L(-1), and after 96 h blood samples were drawn for the micronucleus (MN) test. The LC50-96h was 10.53 mg L(-1), and the MN frequency increased in proportion to the formaldehyde concentrations, with an estimated frequency in the negative control being 1.35 MN/individual. We concluded that formaldehyde is genotoxic to tadpoles of bullfrogs in the tested concentrations, and the choice of this chemical should be contemplated before its use in animals in captivity.

Role of α1-, and α2- and β-adrenoceptors of the median preoptic area on the water intake, renal excretion, and arterial pressure induced by ANG II

The present experiments were conducted to investigate the role of the α1-, α2- and β-adrenergic receptors of the median preoptic area (MnPO) on the water intake and urinary electrolyte excretion, elicited by central injections of angiotensin II (ANG II). Prazosin (an α1-adrenergic receptor antagonist) and yohimbine (an α2-adrenergic receptor antagonist) antagonized the water ingestion, Na +, K +, and urine excretion induced by ANG II. Administration of propranolol, a β-adrenergic receptor antagonist increased the Na +, K +, and urine excretion induced by ANG II. Previous treatment with prazosin and yohimbine reduced the pressor responses to ANG II. These results suggest that the adrenergic neurotransmission in the MnPO may actively participate in ANG II-induced dipsogenesis, natriuresis, kaliuresis, diuresis and pressor responses in a process that involves α1-, α2-, and β-adrenoceptors.

Analysis of association between posterior crossbite, median line deviation and facial asymmetry

Facial asymmetry is a common human characteristic and can occur on many levels, originate of genetic factors, and can be caused by traumas or due to cross bite and/or muscular disability. The aim of this study was to evaluate the relation between posterior crossbite, median line deviation and facial asymmetry. For this study 70 children aged between 3 and 10 years-old were examined and photographed. Using Microsoft Office Power Point 2007, horizontal lines and one vertical line on median line were drawn, to subjectively analyze facial discrepancies. In relation to overjet, the majority of children (78.6%) showed normal relation, followed by high overjet (17.1%), anterior crossbite (4.3%). In relation to overbite, the majority of children (60%) showed normal relation, 27.1% anterior opened bite (negative overbite), and 12.9% showed high overbite. Posterior crossbite was present in 27.1% of children. Among them, 68.4% showed unilateral crossbite on right side, 21.1% bilateral crossbite and 10.5% unilateral crossbite on left side. The relation between posterior crossbite and facial asymmetry, according to Fisher´s Exact Test (p=0.0970), there was no statistically significant association. In relation to median line, the association was statistically significant with posterior crossbite (p=0.0109) and with facial asymmetry (p=0.0310). There was association between posterior crossbite and median line deviation. There was no association between posterior crossbite and facial asymmetry.