Effect of estradiol benzoate microinjection into the median raphe nucleus on contextual conditioning

Estrogen deficiency has been associated with stress, anxiety and depression. Estrogen receptors have been identified in the median raphe nucleus (MRN). This structure is the main source of serotonergic projections to the hippocampus, a forebrain area implicated in the regulation of defensive responses and in the resistance to chronic stress. There is reported evidence indicating that estrogen modulates 5-HT(1A) receptor function. In the MRN, somatodendritic 5-HT(1A) receptors control the activity of serotonergic neurones by negative feedback. The present study has evaluated the effect of intra-MRN injection of estradiol benzoate (EB, 600 or 1200 ng/0.2 mu l) on the performance of ovariectormized rats submitted to contextual conditioning. Additionally, the same treatment was given after intra-MRN injection of Way 100635 (100 ng/0.2 mu l). a 5-HT(1A) receptor antagonist. Both doses of EB decreased freezing and increased rearing, indicating an anxiolytic effect. Pretreatment with Way 100635 antagonized the anxiolytic effect of estradiol. On the basis of these results, it may be suggested that estrogens modulate anxiety by acting on 5-HT(1A) receptors localized in the MRN. (C) 2009 Elsevier B.V. All rights reserved.

Regulation of conditioned and unconditioned fear in rats by 5-HT1A receptors in the dorsal periaqueductal gray

Studies on the involvement of 5-HT1-mediated mechanisms in the dorsal periaqueductal gray (dPAG) of animals with past stressful experiences have not been conducted so far. We investigated the role of 5-HT1 receptors in the dPAG of rats previously submitted to contextual fear conditioning. Defensive behaviors induced by activation of the dPAG were assessed by measuring the lowest electric current applied to this structure (threshold) able to produce freezing and escape responses during testing sessions of contextual fear conditioning, in which animals were placed in a context previously paired to footshocks. The 5-HT1A function of the dPAG was evaluated by local injections of 8-OH-DPAT (4 and 8 nmol/0.2 mu L) and WAY-100635 (10 nmol/0.2 mu L), selective agonist and antagonist of 5-HT1A receptors, respectively. In accordance with previous studies, 8-OH-DPAT increased aversive thresholds (antiaversive effects) but injections of WAY 100635 into the dPAG did not produce significant effects on the aversive thresholds in naive rats. However, the aversive thresholds of animals exhibiting contextual fear remained unchanged with both treatments. Moreover, 8-OH-DPAT and WAY 100635 did not change the dPAG post-stimulation freezing. The present results suggest that the stressful experience of being fear conditioned has an effect on the role of the 5-HT1A receptors in mediating unconditioned fear. Also, the reduction in the regulation of the defensive behaviors by 5-HT1A-mediated mechanisms in the dPAG of these animals may underlie the stress precipitated psychopathology associated with the neural substrates of aversion of the dPAG. (c) 2007 Elsevier Inc. All rights reserved.

Lipopolysaccharide and lipoteichoic acid induce different innate immune responses in bovine mammary epithelial cells

The objective of the present study was to characterize the innate immune responses induced by in vitro stimulation of bovine primary mammary epithelial cells (bMEC) using gram-negative lipopolysaccharide (LPS) and gram-positive lipoteichoic acid (LTA) bacterial cell wall components. Quantitative real-time PCR (qRT-PCR) was employed to examine the mRNA expression of a panel of 22 cytokines, chemokines, beta-defensins and components of the Toll-Like Receptor signaling pathway. Stimulation of bMEC with LPS for 24 h elicited a marked increase in mRNA expression for IL-1 beta, IL-8, TNF alpha, CXCL6 and beta-defensin while members of the Toll-Like Receptor pathway.. although present, were largely unaffected. Surprisingly, stimulation of these cells with LTA for 24 h did not significantly alter the expression of these genes. A time course of the expression of IL-1 beta, IL-8, TNF alpha, CXCL6 and beta-defensin was subsequently performed. The mRNA levels of all genes increased rapidly after stimulation for 2-4 h with both LPS and LTA but only the former treatment resulted in sustained responses. In contrast, the increased gene expression for LTA stimulated cells returned to resting levels after 8-16 h with the exception of beta-defensin, which remained up-regulated. The limited and unsustained cytokine response to LTA may explain why mastitis caused by gram-positive bacteria has greater potential for chronic intra-mammary infection than gram-negative infection. It was concluded that bovine mammary epithelial cells have a strong but differential capacity to mount innate immune responses to bacterial cell wall components. Crown Copyright (c) 2005 Published by Elsevier Ltd. All rights reserved.

A study on stress corrosion cracking and hydrogen embrittlement of AZ31 magnesium alloy

The stress corrosion cracking (SCC) behavior and pre-exposure embrittlement of AZ31 magnesium alloy have been studied by slow strain rate tensile (SSRT) tests in this paper. It is showed that AZ31 sheet material is susceptible to SCC in distilled water, ASTM D1.387 solution, 0.01 M NaCl and 0.1 M NaCl solution. The AZ31 magnesium alloy also becomes embrittled if pre-exposed to 0.01 M NaCl solution prior to tensile testing. The degree of embrittlement increased with increasing the pre-exposure time, It is proposed that both the pre-exposure embrittlement and SCC were due to hydrogen which reduces the cohesive strength. i,e,. hydrogen embrittlement, (c) 2005 Elsevier B.V. All rights reserved.

Bovine mammary epithelial cells, initiators of innate immune responses to mastitis

Innate immunity plays a vital role in the protection of the bovine mammary gland against mastitis. Until recently, the migration of effector cells such as neutrophils and monocytes into the mammary gland was thought to provide the only defence against invading pathogens. However, mammary epithelial cells may also play an important role in the immune response, contributing to the innate defence of the mammary tissue through secretion of antimicrobial peptides and attraction of circulating immune effector cells. This paper reviews the innate immune pathways in mammary epithelial cells and examines their role in the initiation of an innate immune response to Gram-positive and Gram-negative bacteria.

Characterization of optically driven fluid stress fields with optical tweezers

We present a controlled stress microviscometer with applications to complex fluids. It generates and measures microscopic fluid velocity fields, based on dual beam optical tweezers. This allows an investigation of bulk viscous properties and local inhomogeneities at the probe particle surface. The accuracy of the method is demonstrated in water. In a complex fluid model (hyaluronic acid), we observe a strong deviation of the flow field from classical behavior. Knowledge of the deviation together with an optical torque measurement is used to determine the bulk viscosity. Furthermore, we model the observed deviation and derive microscopic parameters.

Seed dormancy and germination responses of nine Australian fire ephemerals

Fire ephemerals are short-lived plants with seeds that persist in the soil and germinate after a fire or physical soil disturbance. Ex situ germination of many Australian fire ephemerals has previously been difficult. Dormancy was present in most of the nine fire ephemerals examined. Alyogyne hakeifolia (Giord.) Alef. and Alyogyne huegelii (Endl.) Fryxell (Malvaceae) seeds had physical and possibly also physiological dormancy, Actinotus leucocephalus Benth. (Apiaceae) seeds had morphophysiological dormancy, Austrostipa compressa (R.Br.) S.W.L. Jacobs & J. Everett and Austrostipa macalpinei (Reader) S.W.L. Jacobs & J. Everett (Poaceae) seeds were either non-dormant or possessed physiological dormancy, and seeds of all remaining species possessed physiological dormancy. A proportion of the Alyogyne hakeifolia, Alyogyne huegelii, Austrostipa compressa and Austrostipa macalpinei seed populations were non-dormant because some seeds could germinate at the various incubation temperatures without further treatment. At 20 degrees C, artificial methods of inducing germination such as manual or acid scarification were among the optimal treatments for Austrostipa compressa, Austrostipa macalpinei, Alyogyne huegelii, Actinotus leucocephalus and Grevillea scapigera A.S. George (Proteaceae), and gibberellic acid induced maximum germination of Tersonia cyathiflora (Fenzl) J.W. Green (Gyrostemonaceae) seeds. Heat (70 degrees C for 1 h) and smoke water was one of the most effective treatments for germinating Actinotus leucocephalus and Codonocarpus cotinifolius (Desf.) F. Muell. (Gyrostemonaceae) seeds. Germination of Grevillea scapigera, Codonocarpus cotinifolius, Gyrostemon racemiger H. Walter (Gyrostemonaceae) and Tersonia cyathiflora did not exceed 40% and may require other treatments to overcome dormancy. Although the nine fire ephemerals examined require fire to germinate under natural conditions, a range of germination responses and dormancy types was observed.

Overcoming original antigenic sin to generate effective immune responses in antigen primed host

Original antigenic sin is failure to mount effective immunity to virus variants in a previously virus infected host. We have previously shown that prior immunity to a virus capsid protein inhibits induction from naive CD8 T cells of an IFN-g response to a MHC class I restricted epitope linked to the capsid protein, following immunisation with a capsid expressing the class I restricted epitope. The inhibition is independent of pre-existing antibody to the viral capsid, and the inhibition is observed in animal lacking B cells. CD8 restricted viral capsid specific T cell responses are also not required, but the inhibition is not observed in IL10 knockout mice. We now demonstrate that capsid antigen primed CD4+ T cells secrete IL10 in response to capsid antigen presented by DC, and deviate CD8 cells specific for the linked MHC Class I restricted epitope from IFN-g production to IL-5 production. Neutralizing IL10, either in vitro or in vivo, restores induction following immunisation of an antigen specific IFN-g response to an MHC Class I restricted epitope. This finding demonstrates a strategy for overcoming bias towards a Tc2 response to MHC Class I epitopes upon immunisation of a host already primed to antigen, facilitating immunotherapy for chronic viral infection or cancer

Effects of Nasal Continuous Positive Airway Pressure Treatment on Oxidative Stress and Adiponectin Levels in Obese Patients with Obstructive Sleep Apnea

Background: Obesity and obstructive sleep apnea (OSA) are both associated with the prevalence of major cardiovascular illnesses and certain common factors they are considered responsible for, such as stress oxidative increase, sympathetic tonus and resistance to insulin. Objective: The aim of the present study was to compare the effect of continuous positive airway pressure (CPAP) on oxidative stress and adiponectin levels in obese patients with and without OSA. Methods: Twenty-nine obese patients were categorized into 3 groups: group 1: 10 individuals without OSA (apnea-hypopnea index, AHI <= 5) who did not have OSA diagnosed at polysomnography; group 2: 10 patients with moderate to severe OSA (AHI >= 20) who did not use CPAP; group 3: 9 patients with moderate to severe OSA (AHI >= 20) who used CPAP. Results: Group 3 showed significant differences before and after the use of CPAP, in the variables of diminished production of superoxide, and increased nitrite and nitrate synthesis and adiponectin levels. Positive correlations were seen between the AHI and the superoxide production, between the nitrite and nitrate levels and the adiponectin levels, between superoxide production and the HOMA-IR, and between AHI and the HOMA-IR. Negative correlations were found between AHI and the nitrite and nitrate levels, between the superoxide production and that of nitric oxide, between the superoxide production and the adiponectin levels, between AHI and the adiponectin levels, and between the nitrite and nitrate levels and the HOMA-IR. Conclusions: This study demonstrates that the use of CPAP can reverse the increased superoxide production, the diminished serum nitrite, nitrate and plasma adiponectin levels, and the metabolic changes existing in obese patients with OSA. Copyright (C) 2009 S. Karger AG, Basel

Effect of phosphate binders on oxidative stress and inflammation markers in hemodialysis patients

It has been suggested that phosphate binders may reduce the inflammatory state of hemodialysis (HD) patients. However, it is not clear whether it has any effect on oxidative stress. The objective of this study was to evaluate the effect of sevelamer hydrochloride (SH) and calcium acetate (CA) on oxidative stress and inflammation markers in HD patients. Hemodialysis patients were randomly assigned to therapy with SH (n=17) or CA (n=14) for 1 year. Before the initiation of therapy (baseline) and at 12 months, we measured in vitro reactive oxygen species (ROS) production by stimulated and unstimulated polymorphonuclear neutrophils and serum levels of tumor necrosis factor alpha, interleukin-10, C-reactive protein, and albumin. There was a significant reduction of spontaneous ROS production in both groups after 12 months of therapy. There was a significant decrease of Staphylococcus aureus stimulated ROS production in the SH group. There was a significant increase in albumin serum levels only in the SH group. In the SH group, there was also a decrease in the serum levels of tumor necrosis factor alpha and C-reactive protein. Our results suggest that compared with CA treatment, SH may lead to a reduction in oxidative stress and inflammation. Therefore, it is possible that phosphate binders exert pleiotropic effects on oxidative stress and inflammation, which could contribute toward decreasing endothelial injury in patients in HD.

In situ immune responses to interstitial pneumonitis in human visceral leishmaniasis

Lung disease during active human visceral leishmaniasis is frequently reported. As such, studies have associated pulmonary symptoms to interstitial pneumonitis with a mononuclear infiltrate. However, the immune response in this condition has never been described before. The aim of this study was to determine the immunophenotypic pattern and cytokine profile of lung involvement (IPL) in human visceral leishmaniasis. Quantitative methods of analysis were performed using immunohistochemistry, and were compared with a control group of normal lung. Interstitial macrophages and cd8 cells were increased in IPL, and IL-4 as well as TNF-alpha displayed increased expression when compared to the control group. This inflammatory process with a Th2 pattern, as suggested by increased IL-4 and low IFN-gamma expression, is consistent with the immune response in other organs of visceral leishmaniasis. The microenvironment of the immune response in this condition is associated with lung disease in patients with interstitial pneumonitis related to visceral leishmaniasis, increasing the chance of bacterial infection.

Application of biotechnology in breeding lentil for resistance to biotic and abiotic stress

Lentil is a self-pollinating diploid (2n = 14 chromosomes) annual cool season legume crop that is produced throughout the world and is highly valued as a high protein food. Several abiotic stresses are important to lentil yields world wide and include drought, heat, salt susceptibility and iron deficiency. The biotic stresses are numerous and include: susceptibility to Ascochyta blight, caused by Ascochyta lentis; Anthracnose, caused by Colletotrichum truncatum; Fusarium wilt, caused by Fusarium oxysporum; Sclerotinia white mold, caused by Sclerotinia sclerotiorum; rust, caused by Uromyces fabae; and numerous aphid transmitted viruses. Lentil is also highly susceptible to several species of Orabanche prevalent in the Mediterranean region, for which there does not appear to be much resistance in the germplasm. Plant breeders and geneticists have addressed these stresses by identifying resistant/tolerant germplasm, determining the genetics involved and the genetic map positions of the resistant genes. To this end progress has been made in mapping the lentil genome and several genetic maps are available that eventually will lead to the development of a consensus map for lentil. Marker density has been limited in the published genetic maps and there is a distinct lack of co-dominant markers that would facilitate comparisons of the available genetic maps and efficient identification of markers closely linked to genes of interest. Molecular breeding of lentil for disease resistance genes using marker assisted selection, particularly for resistance to Ascochyta blight and Anthracnose, is underway in Australia and Canada and promising results have been obtained. Comparative genomics and synteny analyses with closely related legumes promises to further advance the knowledge of the lentil genome and provide lentil breeders with additional genes and selectable markers for use in marker assisted selection. Genomic tools such as macro and micro arrays, reverse genetics and genetic transformation are emerging technologies that may eventually be available for use in lentil crop improvement.

Less inhibited with age? Larval age modifies responses to natural settlement inhibitors

As larvae of marine invertebrates age, their response to settlement cues can change. This change can have significant consequences to both the ecology of these organisms, and to their response to antifouling coatings. This study examines how larval age affects the settlement response of larvae to two naturally derived settlement inhibitors, non-polar extracts from the algae Delisea pulchra and Dilophus marginatus, the former of which contains compounds that are in commercial development as antifoulants. Two species of marine invertebrates with non-feeding larvae were investigated: the bryozoans Watersipora subtorquata and Bugula neritina. Larval age strongly affected larval settlement, with older larvae settling at much higher rates than younger larvae. Despite having strong, inhibitory effects on young larvae, the non-polar extracts did not inhibit the settlement of older larvae to the same degree for both species studied. The results show that the effects of ecologically realistic settlement inhibitors are highly dependent on larval age. Given that the age of settling larvae is likely to be variable in the field, such age specific variation in settlement response of larvae may have important consequences for host-epibiont interactions in natural communities.

Dipyridamole Stress and Rest Myocardial Perfusion by 64-Detector Row Computed Tomography in Patients With Suspected Coronary Artery Disease

Recently, stress myocardial computed tomographic perfusion (CTP) was shown to detect myocardial ischemia. Our main objective was to evaluate the feasibility of dipyridamole stress CTP and compare it to single-photon emission computed tomography (SPECT) to detect significant coronary stenosis using invasive conventional coronary angiography (CCA; stenosis >70%) as the reference method. Thirty-six patients (62 +/- 8 years old, 20 men) with previous positive results with SPECT (<2 months) as the primary inclusion criterion and suspected coronary artery disease underwent a customized multidetector-row CT protocol with myocardial perfusion evaluation at rest and during stress and coronary CT angiography (CTA). Multidetector-row computed tomography was performed in a 64-slice scanner with dipyridamole stress perfusion acquisition before a second perfusion/CT angiographic acquisition at rest. Independent blinded observers performed analysis of images from CTP, CTA, and CCA. All 36 patients completed the CT protocol with no adverse events (mean radiation dose 14.7 +/- 3.0 mSv) and with interpretable scans. CTP results were positive in 27 of 36 patients (75%). From the 9 (25%) disagreements, 6 patients had normal coronary arteries and 2 had no significant stenosis (8 false-positive results with SPECT, 22%). The remaining patient had an occluded artery with collateral flow confirmed by conventional coronary angiogram. Good agreement was demonstrated between CTP and SPECT on a per-patient analysis (kappa 0.53). In 26 patients using CCA as reference, sensitivity, specificity, and positive and negative predictive values were 88.0%, 79.3%, 66.7%, and 93.3% for CTP and 68.8, 76.1%, 66.7%, and 77.8%, for SPECT, respectively (p = NS). In conclusion, dipyridamole CT myocardial perfusion at rest and during stress is feasible and results are similar to single-photon emission CT scintigraphy. The anatomical-perfusion information provided by this combined CT protocol may allow identification of false-positive results by SPECT. (C) 2010 Elsevier Inc. All rights reserved. (Am J Cardiol 2010;106:310-315)