The Impact of Stressor Exposure and Glucocorticoids on Anxiety and Fear

Anxiety disorders and trauma- and stressor-related disorders, such as posttraumatic stress disorder (PTSD), are common and are associated with significant economic and social burdens. Although trauma and stressor exposure are recognized as a risk factors for development of anxiety disorders and trauma or stressor exposure is recognized as essential for diagnosis of PTSD, the mechanisms through which trauma and stressor exposure lead to these disorders are not well characterized. An improved understanding of the mechanisms through which trauma or stressor exposure leads to development and persistence of anxiety disorders or PTSD may result in novel therapeutic approaches for the treatment of these disorders. Here, we review the current state-of-the-art theories, with respect to mechanisms through which stressor exposure leads to acute or chronic exaggeration of avoidance or anxiety-like defensive behavioral responses and fear, endophenotypes in both anxiety disorders and trauma- and stressor-related psychiatric disorders. In this chapter, we will explore physiological responses and neural circuits involved in the development of acute and chronic exaggeration of anxiety-like defensive behavioral responses and fear states, focusing on the role of the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoid hormones.

Numerical Modelling of the Mould Filling Stage in Gas-Assisted Injection Moulding

This paper presents an effective numerical model capable of simulating the filling stage of the gas-assisted injection molding process, particularly the gas penetration phenomenon involving the gas-polymer interaction. A Galerkin Finite Element model is used to model the polymer flow during the filling and gas penetration stages. The polymer flow front and the gas-polymer interface are tracked using a volume tracking technique. Finally, a finite difference technique has been used to calculate the temperature across the thickness. Comparison between numerical simulation predictions and the experimental data for a plate mould as well as for a complex part is presented.

Extrusion of Recycled Polymer Feedstocks

The increased emphasis on the use of recycled feedstocks has brought in the need for continuous on-line monitoring of process conditions. This is done in an effort to detect process shifts and react accordingly to maintain optimal conditions. Time series analysis is ideal for on-line modelling of continuous processes employing recycled feedstocks, as the disturbances present in the feedstock can be quantified using this approach. The models obtained can then be employed for closed loop control of the process. The closed loop control allows for maximizing of the amount of recycled material, yet ensuring an acceptable finished product.

This work presents a study of the stochastic dynamics of the extrusion of recycled feedstocks. Both “in-house” and “post-consumer” feedstocks are considered. Process outputs include the extrudate thickness and diameter, the head pressure, the melt temperature and the flowrate. The process inputs are the die gap and the level of recycle material. Process and disturbance transfer function models are obtained.

Control simulations are performed on the process and disturbance models to ascertain the feasibility of a closed loop system for maintaining of optimal process conditions. A minimum variance controller (MVC) is employed in the simulation. The response of the closed loop system to various disturbance inputs is monitored. The control scheme results in a much lower offset from the set point for the case with MVC than for the case with no control.

A rapid and sensitive fluorometric method for the quantitative analysis of snake venom metalloproteases and their inhibitors

Metalloproteases are responsible for the hemorrhagic effects of many snake venoms and contribute to other pathways that lead to local tissue damage. Methods that quantify snake venom metalloproteases (SVMP) are therefore valuable tools in research on the clinical, physiological, and biochemical effects of envenomation. Comparative analysis of individual, population, and species differences requires screening of large numbers of samples and treatments, and therefore require a method of quantifying SVMP activity that is simple, rapid, and sensitive. This paper demonstrates the properties of a new fluorometric assay of SVMP activity that can provide a measure of metalloprotease activity in 1 h. The assay is reliable, with variation among replicates sufficiently small to reliably detect differences in between species (F(19,60) = 2924, p < 0.001), even for those venoms with low overall activity. It is also sensitive enough to detect differences among venoms using <2 ng of whole venom protein. We provide an example use of this assay to detect the presence of natural SVMP inhibitors in minute samples of blood plasma from rock squirrels (S. variegatus), a natural prey species for North American rattlesnakes. We propose this assay is a useful addition to the set of tools used to characterize venoms, as well as high-throughput screening of natural or synthetic inhibitors, or other novel therapeutic agents against SVMP effects.

Identification of undiagnosed type 2 diabetes by systolic blood pressure and waist-to-hip ratio

AIMS/HYPOTHESIS

We estimated the current prevalence of type 2 diabetes in the Vietnamese population and developed simple diagnostic models for identifying individuals at high risk of undiagnosed type 2 diabetes.

METHODS

The study was designed as a cross-sectional investigation with 721 men and 1,421 women, who were aged between 30 and 72 years and were randomly sampled from Ho Chi Minh City (formerly Saigon) in Vietnam. A 75 g oral glucose tolerance test to assess fasting and 2 h plasma glucose concentrations were determined for each individual. The ADA diagnostic criteria were used to determine the prevalence of type 2 diabetes. WHR and blood pressure were also measured in all individuals.

RESULTS

The prevalence of type 2 diabetes was 10.8% in men and 11.7% in women. Higher WHR and blood pressure were independently associated with a greater risk of type 2 diabetes. Compared with participants without central obesity and hypertension, the odds of diabetes was increased by 6.4-fold (95% CI 3.2-13.0) in men and 4.1-fold (2.2-7.6) in women with central obesity and hypertension. Two nomograms were developed that help identify men and women at high risk of type 2 diabetes.

CONCLUSIONS/INTERPRETATION

The current prevalence of type 2 diabetes in the Vietnamese population is high. Simple field measurements such as waist-to-hip ratio and systolic blood pressure can identify individuals at high risk of undiagnosed type 2 diabetes.

Synergistic effect between EGF and TGF-beta1 in inducing oncogenic properties of intestinal epithelial cells

Transforming growth factor (TGF)-beta1 has a biphasic effect on rat intestinal epithelial (RIE) cells. By itself, TGF-beta1 functions as a tumor suppressor by inhibiting the growth, migration and invasion of RIE cells. We show in this study that in conjunction with epidermal growth factor (EGF), TGF-beta1 helped to augment migration, invasion and anchorage-independent growth (AIG) compared to that by EGF alone. EGF plus TGF-beta1 induced a dramatic morphological change characteristic of epithelial-mesenchymal transition (EMT). The mechanism for this enhanced effect of TGF-beta1 and EGF on oncogenic properties was explored by analysis of EGF- and TGF-beta1-mediated signaling pathways and complementary DNA arrays. TGF-beta1 augmented EGF-mediated signaling of mitogen-activated protein kinase (MAPK) and AKT by enhancing and prolonging the activation of the former and prolonging the activation of the latter. Inhibition of MAPK, but not phosphoinositide-3 kinase (PI3K), abolished TGF-beta1 plus EGF-induced EMT and downregulation of E-cadherin at mRNA and protein levels. By contrast, cell migration and invasion were sensitive to inhibition of either MAPK or PI3 kinase. TGF-beta1 plus EGF-induced AIG was significantly more resistant to inhibition of PI3K and MAPK compared to that induced by EGF alone. EGF and TGF-beta1 synergistically induced the expression of a series of proteases including matrix metalloproteinase (MMP) 1 (collagenase), MMP3, MMP9, MMP10, MMP14 and cathepsin. Among them, the expression of MMP1, MMP3, MMP9 and MMP10 was MAPK dependent. Inhibition of the MMPs or cathepsin significantly blocked EGF plus TGF-beta1-induced invasion, but had no effect on colony formation. Phospholipase C (PLC) and Cox2 induced by EGF plus TGF-beta1 also played a significant role in invasion, whereas PLC was also important for colony formation. Our study reveals specific signaling functions and induction of genes differentially required for enhanced effect of EGF- and TGF-beta1-induced oncogenic properties, and helps to explain the tumor-promoting effect of TGF-beta1 in human cancer with elevated expression or activation of TGF-beta1 and receptor protein tyrosine kinases.

In vitro hemocompatibility studies of drug-loaded poly-(L-lactic acid) fibers

Our objective was to evaluate the hemocompatibility of biodegradable stent fibers, employing a closed-loop circulation system filled with human blood. We also investigated the effects of the anti-inflammatory and anti-proliferative drugs curcumin and paclitaxel, incorporated into stent fibers. Fresh whole blood was circulated in four parallel closed-loop systems: the empty tube circuit (control) and tubes containing either a PLLA fiber coil (PLLA), a curcumin-loaded PLLA coil (C-PLLA) or a paclitaxel-loaded PLLA coil (P-PLLA). The influence of PLLA fiber, alone or loaded with drug incorporated during melt-extrusion, on leukocyte and platelet adhesion and activation was determined by flow cytometry. The effects of blood flow and fiber properties on cell deposition were assessed by scanning electron microscopy (SEM). The flow cytometry results clearly demonstrated that PLLA triggers blood cell activation at the site of deployment, as shown by increases in CD11b, CD62P and leukocyte-platelet aggregates, compared to controls. Curcumin and paclitaxel treatments both significantly reduced leukocyte and platelet activation and adhesion to PLLA fibers, as shown by flow cytometry and SEM. Activated leukocytes and platelets revealed significantly lower CD11b and CD62P receptor binding for C-PLLA compared with PLLA alone, and slightly lower for P-PLLA. Reductions in platelet-leukocyte aggregates were observed as well. In addition, there was less leukocyte and platelet adhesion to C-PLLA, compared with PLLA fiber controls, as shown by SEM. A continuous linear thrombus, composed of platelets, leukocytes, red blood cells and fibrin was occasionally detected along the line of tangency between the coil and the tube wall. Flow separation and eddying, proximal and distal to the line of tangency of coil and tube, is thought to contribute to this deposit. Curcumin was more effective than paclitaxel in reducing leukocyte and platelet activation and adhesion to PLLA stent fibers in this setting. However there was evidence of paclitaxel degeneration during melt extrusion that may have inhibited its effectiveness. Incorporation of the anti-inflammatory and anti-proliferative drug curcumin into bioresorbable stent fibers is proposed to prevent thrombosis and in-stent restenosis.

Characterization of an eukaryotic peptide deformylase from Plasmodium falciparum

Ribosomal protein synthesis in eubacteria and eukaryotic organelles initiates with an N-formylmethionyl-tRNA(i), resulting in N-terminal formylation of all nascent polypeptides. Peptide deformylase (PDF) catalyzes the subsequent removal of the N-terminal formyl group from the majority of bacterial proteins. Until recently, PDF has been thought as an enzyme unique to the bacterial kingdom. Searches of the genomic DNA databases identified several genes that encode proteins of high sequence homology to bacterial PDF from eukaryotic organisms. The cDNA encoding Plasmodium falciparum PDF (PfPDF) has been cloned and overexpressed in Escherichia coli. The recombinant protein is catalytically active in deformylating N-formylated peptides, shares many of the properties of bacterial PDF, and is inhibited by specific PDF inhibitors. Western blot analysis indicated expression of mature PfPDF in trophozoite, schizont, and segmenter stages of intraerythrocytic development. These results provide strong evidence that a functional PDF is present in P. falciparum. In addition, PDF inhibitors inhibited the growth of P. falciparum in the intraerythrocytic culture.

Pleiotropic functions of a Streptomyces pristinaespiralis autoregulator receptor in development, antibiotic biosynthesis, and expression of a superoxide dismutase

In Streptomyces, a family of related butyrolactones and their corresponding receptor proteins serve as quorum-sensing systems that can activate morphological development and antibiotic biosynthesis. Streptomyces pristinaespiralis contains a gene cluster encoding enzymes and regulatory proteins for the biosynthesis of pristinamycin, a clinically important streptogramin antibiotic complex. One of these proteins, PapR1, belongs to a well known family of Streptomyces antibiotic regulatory proteins. Gel shift assays using crude cytoplasmic extracts detected SpbR, a developmentally regulated protein that bound to the papR1 promoter. SpbR was purified, and its gene was cloned using reverse genetics. spbR encoded a 25-kDa protein similar to Streptomyces autoregulatory proteins of the butyrolactone receptor family, including scbR from Streptomyces coelicolor. In Escherichia coli, purified SpbR and ScbR produced bound sequences immediately upstream of papR1, spbR, and scbR. SpbR DNA-binding activity was inhibited by an extracellular metabolite with chromatographic properties similar to those of the well known gamma-butyrolactone signaling compounds. DNase I protection assays mapped the SpbR-binding site in the papR1 promoter to a sequence homologous to other known butyrolactone autoregulatory elements. A nucleotide data base search showed that these binding motifs were primarily located upstream of genes encoding Streptomyces antibiotic regulatory proteins and butyrolactone receptors in various Streptomyces species. Disruption of the spbR gene in S. pristinaespiralis resulted in severe defects in growth, morphological differentiation, pristinamycin biosynthesis, and expression of a secreted superoxide dismutase.

Cyclic strain increases protease-activated receptor-1 expression in vascular smooth muscle cells

Cyclic strain regulates many vascular smooth muscle cell (VSMC) functions through changing gene expression. This study investigated the effects of cyclic strain on protease-activated receptor-1 (PAR-1) expression in VSMCs and the possible signaling pathways involved, on the basis of the hypothesis that cyclic strain would enhance PAR-1 expression, reflecting increased thrombin activity. Uniaxial cyclic strain (1 Hz, 20%) of cells cultured on elastic membranes induced a 2-fold increase in both PAR-1 mRNA and protein levels. Functional activity of PAR-1, as assessed by cell proliferation in response to thrombin, was also increased by cyclic strain. In addition, treatment of cells with antioxidants or an NADPH oxidase inhibitor blocked strain-induced PAR-1 expression. Preincubation of cells with protein kinase inhibitors (staurosporine or Ro 31-8220) enhanced strain-increased PAR-1 expression, whereas inhibitors of NO synthase, tyrosine kinase, and mitogen-activated protein kinases had no effect. Cyclic strain in the presence of basic fibroblast growth factor induced PAR-1 mRNA levels beyond the effect of cyclic strain alone, whereas no additive effect was observed between cyclic strain and platelet-derived growth factor-AB. Our findings that cyclic strain upregulates PAR-1 mRNA expression but that shear stress downregulates this gene in VSMCs provide an opportunity to elucidate signaling differences by which VSMCs respond to different mechanical forces.

Roles of aconitase in growth, metabolism, and morphological differentiation of Streptomyces coelicolor

The studies of aconitase presented here, along with those of citrate synthase (P. H. Viollier, W. Minas, G. E. Dale, M. Folcher, and C. J. Thompson, J. Bacteriol. 183:3184-3192, 2001), were undertaken to investigate the role of the tricarboxylic acid (TCA) cycle in Streptomyces coelicolor development. A single aconitase activity (AcoA) was detected in protein extracts of cultures during column purification. The deduced amino acid sequence of the cloned acoA gene constituted the N-terminal sequence of semipurified AcoA and was homologous to bacterial A-type aconitases and bifunctional eukaryotic aconitases (iron regulatory proteins). The fact that an acoA disruption mutant (BZ4) did not grow on minimal glucose media in the absence of glutamate confirmed that this gene encoded the primary vegetative aconitase catalyzing flux through the TCA cycle. On glucose-based complete medium, BZ4 had defects in growth, antibiotic biosynthesis, and aerial hypha formation, partially due to medium acidification and accumulation of citrate. The inhibitory effects of acids and citrate on BZ4 were partly suppressed by buffer or by introducing a citrate synthase mutation. However, the fact that growth of an acoA citA mutant remained impaired, even on a nonacidogenic carbon source, suggested alternative functions of AcoA. Immunoblots revealed that AcoA was present primarily during substrate mycelial growth on solid medium. Transcription of acoA was limited to the early growth phase in liquid cultures from a start site mapped in vitro and in vivo.

Intrathecal HIV-1 envelope glycoprotein gp120 induces enhanced pain states mediated by spinal cord proinflammatory cytokines

Perispinal (intrathecal) injection of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein gp120 creates exaggerated pain states. Decreases in response thresholds to both heat stimuli (thermal hyperalgesia) and light tactile stimuli (mechanical allodynia) are rapidly induced after gp120 administration. gp120 is the portion of HIV-1 that binds to and activates microglia and astrocytes. These glial cells have been proposed to be key mediators of gp120-induced hyperalgesia and allodynia because these pain changes are blocked by drugs thought to affect glial function preferentially. The aim of the present series of studies was to determine whether gp120-induced pain changes involve proinflammatory cytokines [interleukin-1beta (IL-1) and tumor necrosis factor-alpha (TNF-alpha)], substances released from activated glia. IL-1 and TNF antagonists each prevented gp120-induced pain changes. Intrathecal gp120 produced time-dependent, site-specific increases in TNF and IL-1 protein release into lumbosacral CSF; parallel cytokine increases in lumbar dorsal spinal cord were also observed. Intrathecal administration of fluorocitrate (a glial metabolic inhibitor), TNF antagonist, and IL-1 antagonist each blocked gp120-induced increases in spinal IL-1 protein. These results support the concept that activated glia in dorsal spinal cord can create exaggerated pain states via the release of proinflammatory cytokines.

Endogenous glucocorticoids play a positive regulatory role in the anti-keyhole limpet hemocyanin in vivo antibody response

Glucocorticoids (GCs) are commonly reported to be immunosuppressive. Studies that support this involve the administration of synthetic GCs such as dexamethasone at high pharmacological doses and using in vitro assay systems that may have limited relevance to the role of GCs during normal in vivo immune responses. Therefore, the following experiments tested the conclusion that GCs are generally immunosuppressive. Adult male Sprague Dawley rats received adrenalectomy (ADX) or sham surgery. ADX rats were given either basal corticosterone (CORT) replacement in their drinking water (25 microg/ml) or no CORT. Rats were immunized with keyhole limpet hemocyanin (KLH), and blood samples were taken. ADX rats with no CORT replacement had reduced anti-KLH IgM and IgG responses compared with sham-operated controls. ADX rats that received basal CORT replacement had partially restored anti-KLH IgM, but still had suppressed anti-KLH IgG. Administration of GC receptor type I (RU28318) and type II (RU40555) receptor antagonists also reduced the anti-KLH IgM and IgG responses. ADX rats that received both basal CORT replacement and low dose injections of CORT on days 5 and 7 after KLH had anti-KLH IgG levels equal to those of sham-operated controls. Finally, the GC elevation 4-7 days after immunization may play a role in stimulating the IgM to IgG2a switch. GC receptor blockade reduced the anti-KLH IgG2a and splenic IFN-gamma, but not the anti-KLH IgG1, response. Given that IFN-gamma is an important regulator of the IgM to IgG2a switch, it is possible that the small rise in GC found 4-7 days after KLH facilitates IgG2a isotype switching.

Shear stress reduces protease activated receptor-1 expression in human endothelial cells

Shear stress has been shown to regulate several genes involved in the thrombotic and proliferative functions of endothelial cells. Thrombin receptor (protease-activated receptor-1: PAR-1) increases at sites of vascular injury, which suggests an important role for PAR-1 in vascular diseases. However, the effect of shear stress on PAR-1 expression has not been previously studied. This work investigates effects of shear stress on PAR-1 gene expression in both human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (HMECs). Cells were exposed to different shear stresses using a parallel plate flow system. Northern blot and flow cytometry analysis showed that shear stress down-regulated PAR-1 messenger RNA (mRNA) and protein levels in both HUVECs and HMECs but with different thresholds. Furthermore, shear-reduced PAR-1 mRNA was due to a decrease of transcription rate, not increased mRNA degradation. Postshear stress release of endothelin-1 in response to thrombin was reduced in HUVECs and HMECs. Moreover, inhibitors of potential signaling pathways applied during shear stress indicated mediation of the shear-decreased PAR-1 expression by protein kinases. In conclusion, shear stress exposure reduces PAR-1 gene expression in HMECs and HUVECs through a mechanism dependent in part on protein kinases, leading to altered endothelial cell functional responses to thrombin.

Effects of vagotomy on lipopolysaccharide-induced brain interleukin-1beta protein in rats

The production of interleukin-1beta (IL-1beta) in brain is thought to be a critical step in the induction of central manifestations of the acute phase response, and the vagus nerve has been implicated in immune-to-brain communication. Thus, this study examined the effects of intraperitoneal (i.p.) injections of lipopolysaccharide (LPS) on brain IL-1beta protein levels in control and subdiaphragmatically vagotomized rats. In the first experiment, vagotomized and sham-operated male Sprague-Dawley rats were injected i.p. with one of three doses (10, 50, 100 microg/kg) of LPS or vehicle (sterile, pyrogen-free saline) and sacrificed 2 h after the injection. In the second experiment, vagotomized and sham-operated rats were injected i.p. with 100 microg/kg LPS or vehicle and sacrificed 1 h after the injection. The i.p. injection of LPS dose-dependently increased IL-1beta protein levels in the hypothalamus, hippocampus, dorsal vagal complex, cerebellum, posterior cortex, and pituitary 2 h after the injection. Brain and pituitary IL-1beta levels were also significantly increased 1 h after the injection of 100 microg/kg LPS. There were no significant differences in brain IL-1beta levels between sham-operated and vagotomized rats at either the 2 h or 1 h time points. The current data are consistent with previous studies showing increases in brain IL-1beta after peripheral injections of LPS, and support the notion that brain IL-1beta is a mediator in the illness-induction pathway. Furthermore, these data indicate that, at the doses and times tested, subdiaphragmatic vagal afferents are not crucial for LPS-induced brain IL-1beta protein.

Differential requirements of the MAP kinase and PI3 kinase signaling pathways in Src- versus insulin and IGF-1 receptors-induced growth and transformation of rat intestinal epithelial cells

There have been few studies on the specific signaling pathways involved in the transformation of epithelial cells by oncogenic protein tyrosine kinases. Here we investigate the requirement of MAP (MAPK) and phosphatidylinositol 3- (PI3K) kinases in the transformation of rat intestinal epithelial (RIE) cells by oncogenic forms of insulin receptor (gag-IR), insulin-like growth factor-1 receptor (gag-IGFR), and v-Src. MAPK is not significantly activated in cells transformed by gag-IR and gag-IGFR but is activated in v-Src transformed cells. Treatment with PD98059, a MEK inhibitor, at concentrations where MAPK activity was reduced below the basal level showed that MAPK is partially required for the monolayer growth of parental and transformed RIE cells. However, MAPK is not essential for the focus forming ability of the three oncogene-transformed cells. It is also not necessary for the colony forming ability of gag-IR- and gag-IGFR-, but is partially required for v-Src-transformed cells. PI3K is significantly activated in all three oncogene transformed RIE cells. LY294002, a PI3K inhibitor, potently inhibited monolayer growth of all three oncogene-transformed cells. However, at concentrations of LY294002 where activated forms of Akt, a downstream component of the PI3K pathway, were undetectable, colony and focus forming abilities of the v-Src-RIE cells were only slightly affected whereas those of gag-IR/IGFR-RIE cells were greatly inhibited. These results were confirmed using a different pharmacological inhibitor, wortmannin, and a dominant negative form of PI3K, Ap85. Similarly, rapamycin, known to inhibit p70S6 kinase, a downstream component of the PI3K-Akt pathway, also inhibited gag-IR/IGFR-induced, but not v-Src-induced, focus and colony formation. We conclude that the MAPK and PI3K signaling pathways are differentially required for transformation of RIE cells by oncogenic IR and IGFR versus Src and the pattern of requirements is different from that of fibroblast transformation.

Successful laser-assisted percutaneous extraction of four pacemaker leads associated with large vegetations

A man with four endocardial pacemaker leads and two vegetations (1.5 cm and 1 cm) underwent successful percutaneous laser-assisted lead extraction. Although this procedure was complicated by embolization to a left pulmonary arterial branch, the patient recovered without sequelae. This article reviews the literature on lead extraction associated with large vegetations.

Timecourse and corticosterone sensitivity of the brain, pituitary, and serum interleukin-1beta protein response to acute stress

Activation of peripheral immune cells leads to increases of interleukin-1beta (IL-1beta) mRNA, immunoreactivity, and protein levels in brain and pituitary. Furthermore, IL-1beta in brain plays a role in mediating many of the behavioral, physiological, and endocrine adjustments induced by immune activation. A similarity between the consequences of immune activation and exposure to stressors has often been noted, but the potential relationship between stress and brain IL-1beta has received very little attention. A prior report indicated that exposure to inescapable tailshocks (IS) raised levels of brain IL-1beta protein 2 h after IS, but only in adrenalectomized (and basal corticosterone replaced) subjects. The studies reported here explore this issue in more detail. A more careful examination revealed that IL-1beta protein levels in hypothalamus were elevated by IS in intact subjects, although adrenalectomy, ADX (with basal corticosterone replacement) exaggerated this effect. IL-1beta protein increases were already present immediately after the stress session, both in the hypothalamus and in other brain regions in adrenalectomized subjects, and no longer present 24 h later. Furthermore, IS elevated levels of IL-1beta protein in the pituitary, and did so in both intact and adrenalectomized subjects. IS also produced increased blood levels of IL-1beta, but only in adrenalectomized subjects. Finally, the administration of corticosterone in an amount that led to blood levels in adrenalectomized subjects that match those produced by IS, inhibited the IS-induced rise in IL-1beta in hypothalamus and pituitary, but not in other brain regions or blood.

Effects of vagotomy on serum endotoxin, cytokines, and corticosterone after intraperitoneal lipopolysaccharide

The vagus nerve appears to play a role in communicating cytokine signals to the central nervous system, but the exact extent of its involvement in cytokine-to-brain communication remains controversial. Recently, subdiaphragmatic vagotomy was shown to increase bacterial translocation across the gut barrier and thus may cause endotoxin tolerance. The current experiment tested whether or not vagotomized animals have similar systemic responses to endotoxin challenge as do sham-operated animals. Subdiaphragmatically vagotomized and sham-operated animals were injected intraperitoneally with one of three doses (10, 50, 100 microg/kg) of lipopolysaccharide (LPS) or vehicle, and blood samples were taken at 15, 30, 60, 90, and 120 min after the injection. The intraperitoneal injection of LPS increased circulating LPS levels at all time points examined. In addition, all three doses of LPS significantly increased serum interleukin (IL)-1beta, IL-6, and corticosterone in both control and vagotomized rats. In conclusion, vagotomy itself has no marked effect on circulating endotoxin levels or the production of IL-1beta, IL-6, or corticosterone in blood after an intraperitoneal injection of LPS.

Role of interleukin-1 beta in impairment of contextual fear conditioning caused by social isolation

Isolating rats immediately after conditioning impairs contextual but not auditory-cue fear conditioning. The reported experiments examine the involvement of brain interleukin-1beta (IL-1beta) in the impairment in contextual fear conditioning caused by social isolation. As measured by the conditioned freezing response, 5 h of social isolation after conditioning, impaired contextual but not auditory-cue fear conditioning in adult male Sprague-Dawley rats. Social isolation for 1 or 3 h after conditioning also increased IL-1beta protein in the hippocampus and cerebral cortex. No differences in IL-1beta protein levels were found in the pituitary or the hypothalamus. Intracerebroventricular (ICV) IL-1 receptor antagonist (IL-1ra) given after conditioning prevented the impairment in contextual fear conditioning caused by isolation. ICV IL-1ra had no effect on auditory-cue fear conditioning in these same animals, nor did it affect the level of contextual fear conditioning displayed by home cage controls. Like isolation, ICV IL-1beta (10 or 20 ng) after conditioning also impaired contextual but not auditory-cue fear conditioning. These results suggest that increased levels of brain IL-1beta play a role in producing the impairment in contextual fear conditioning produced by social isolation. These findings also add to the generality of the idea that stressors induce IL-1beta activity in the brain and that IL-1beta may play physiological roles in the uninjured brain.

Long-term changes in mineralocorticoid and glucocorticoid receptor occupancy following exposure to an acute stressor

Stressors produce rapid activation of the hypothalamic-pituitary-adrenal axis, which typically resolves within 60-90 min following termination of the stressor. In addition, some stressors such as inescapable tailshock (IS) also produce elevated basal levels of corticosterone (CORT), and reduced serum levels of corticosteroid binding globulin (CBG). The elevated basal levels of CORT produced by IS are only observed at the trough of the circadian rhythm of CORT secretion, and are sustained for 2-3 days following stressor termination. The goal of the following experiments was to determine the extent to which the elevated basal levels of CORT observed following IS exposure produced greater corticosteroid receptor occupancy in the brain and pituitary. To do so, rats (n=8-10 per group) received either sham or bilateral adrenalectomy (with CORT replacement in their drinking water; 25 microg/ml) and were given 3 days to recover. Rats were then exposed to 100 ISs (1.6 mA, 5 s each) administered on a 60 s variable intertrial interval, or remained in their home cages. As seen previously, IS produced an increase in basal CORT (5 microg/dl) and a decrease in CBG (30% decrease). Rats were sacrificed 24 h following IS for trunk blood samples and brain dissections. IS exposure had very little effect on corticosteroid receptor protein expression as determined by mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) binding levels in ADX rats. In addition, no changes in whole cell GR levels (as detected by Western blot) were observed in sham rats exposed to IS. On the other hand, IS exposure led to greater occupancy of MR (ranging from 25%-50%) in hippocampus, hypothalamus, pituitary, and posterior cortex. IS also produced greater occupancy of GR (approximately 20%) in hypothalamus and posterior cortex. These long-term changes in corticosteroid receptor activation, evident 24 h after IS exposure, may be responsible for some of the long-term neural, behavioral and immune changes observed following this acute stress procedure.

Acute stress may facilitate recovery from a subcutaneous bacterial challenge

The effects of stress on the immune system vary with both the duration and type of stressor. Many studies suggest that stress may compromise an organism's ability to recover from immune challenge. However, recent findings suggest that stress may actually enhance some aspects of immune function. For example, exposure to a single session ( approximately 2 h) of intermittent inescapable tailshocks (IS) has been shown to activate the acute phase response and increase some aspects of macrophage function. Thus, the following experiments assessed whether IS exposure would alter local inflammation produced by peripheral injection of streptomycin-killed bacteria. Rats (Harlan Sprague Dawley) were exposed to IS (100 1. 6-mA, 60 s variable intertrial interval) and injected with Escherichia coli ( approximately 2.5 x 10(8) CFU s.c. posterior to the shoulder blades). The area of inflammation was measured until the inflammation had completely resolved (typically 7-8 days). When bacteria were administered immediately after IS, rats resolved inflammation significantly faster than did nonstressed rats. Since adrenalectomy did not reduce the effect of IS, it is unlikely that this effect is a result of elevated corticosterone levels. Furthermore, IS does not appear to alter the rat's ability to sequester bacteria in the subcutaneous space since no swelling of lymph nodes or chronic activation of the hypothalamic-pituitary-adrenal axis was observed.

Dynamic regulation of the proinflammatory cytokine, interleukin-1beta: molecular biology for non-molecular biologists

Interleukin-1beta (IL-1beta) is a key mediator and modulator of a wide array of physiological responses important for survival. It is created by a variety of cell types, including immune cells, glia, and neurons. It is a very potent biological molecule, acting both at the periphery as well as within the central nervous system. The production and release of IL-1beta is tightly regulated by far more complex processes than previously thought. An appreciation of this complexity is necessary for proper interpretation of apparent contradictions in the literature where different aspects of IL-1beta expression are measured. Given that many researchers are not molecular biologists by training, yet need an appreciation of the controls that regulate the function of key proteins such as IL-1beta, this review is aimed at both: (a) clarifying the multiple levels at which IL-1beta production is modulated and (b) using IL-1beta regulation to explain the dynamics of gene regulation to non-molecular biologists. Three major topics will be discussed. First, regulation of IL-1beta production will be examined at every level from extracellular signals that trigger gene activation through release of active protein into the extracellular fluid. Second, regulation of IL-1beta bioavailability and bioactivity will be discussed. This section examines the fact that even after IL-1beta is released, it may or may not be able to exert a biological action due to multiple modulatory factors. Last is the introduction of the idea that IL-1beta regulation is, at times, beyond the direct control of host; that is, when IL-1beta production becomes dysregulated by pathogens.

Design and synthesis of potent, selective, and orally bioavailable tetrasubstituted imidazole inhibitors of p38 mitogen-activated protein kinase

Novel potent and selective diarylimidazole inhibitors of p38 MAP (mitogen-activated protein) kinase are described which have activity in both cell-based assays of tumor necrosis factor-alpha (TNF-alpha) release and an animal model of rheumatoid arthritis. The SAR leading to the development of selectivity against c-Raf and JNK2alpha1 kinases is presented, with key features being substitution of the 4-aryl ring with m-trifluoromethyl and substitution of the 5-heteroaryl ring with a 2-amino substituent. Cell-based activity was significantly enhanced by incorporation of a 4-piperidinyl moiety at the 2-position of the imidazole which also enhanced aqueous solubility. In general, oral bioavailability of this class of compounds was found to be poor unless the imidazole was methylated on nitrogen. This work led to identification of 48, a potent (p38 MAP kinase inhibition IC50 0.24 nM) and selective p38 MAP kinase inhibitor which inhibits lipopolysaccharide-stimulated release of TNF-alpha from human blood with an IC50 2.2 nM, shows good oral bioavailability in rat and rhesus monkey, and demonstrates significant improvement in measures of disease progression in a rat adjuvant-induced arthritis model.

Motor performance with a simulated artificial limb

The present study was conducted to examine performance differences on a reaching and grasping task related to an activity of daily living. This involved either the anatomical limb or a simulated artificial limb. College-aged volunteers (2 men and 4 women), one of whom was left-handed, performed the reaching and grasping task. The apparatus, placed on a table before the seated participant, was a square wooden board which contained a starting key and holes for the insertion and removal of a small Fiberglas dowel. At the beginning of the trial the participant depressed the start key, reached forward and grasped the dowel, and then returned the dowel to a finishing hole located directly in front of the start key. The results of 2 (side) x 2 (type of limb) repeated-measures multivariate analyses of variance on the mean and standard deviation of the movement times showed a significant main effect for type of limb (Wilks lambda 3,3 = .047 and .079, respectively, p < .05). Analyses of variance on mean total transport time, extension time, flexion time, and their standard deviations showed that times were slower and less consistent with the prosthesis for all measures. These results and those of later research should be focused on the development of training principles for both therapists and individuals with an amputation. In addition, the simulated prosthesis is an excellent experimental model for basic and clinical research in the control and acquisition of coordinated movement.

Construction of a genomic map ofMoraxella (Branhamella) catarrhalisATCC 25238 and physical mapping of virulence-associated genes

A physical genome map of the Moraxella catarrhalis type strain (ATCC 25238) has been constructed using pulsed field gel electrophoresis. Macrorestriction analyses of the genome of M. catarrhalis were performed by digestion with the restriction enzymes SmaI, NotI, and RsrII, which cleave the single circular chromosome into 9, 10, and 6 fragments, respectively. The chromosomal fragments generated by pulsed field gel electrophoresis were converted to a linkage map utilizing a combination of partial digestions, and cross-hybridizations. Moraxella catarrhalis, like a number of other respiratory pathogens, has a relatively small genome estimated at 1750 kilobase pairs or about 40% of the size of the Escherichia coli genome. The locations of the four ribosomal RNA operons (rrnLS) were determined by Southern hybridization and by digestion with I-CeuI endonuclease. A number of genes involved in virulence have been placed onto the physical map by Southern hybridization including those encoding the predominant outer-membrane proteins and the chromosomal gene encoding beta-lactamase.Key words: Moraxella catarrhalis, physical map, genome analysis, pulsed-field gel electrophoresis, virulence.

Construction of a genomic map of Moraxella (Branhamella) catarrhalis ATCC 25238 and physical mapping of virulence-associated genes

A physical genome map of the Moraxella catarrhalis type strain (ATCC 25238) has been constructed using pulsed field gel electrophoresis. Macrorestriction analyses of the genome of M. catarrhalis were performed by digestion with the restriction enzymes SmaI, NotI, and RsrII, which cleave the single circular chromosome into 9, 10, and 6 fragments, respectively. The chromosomal fragments generated by pulsed field gel electrophoresis were converted to a linkage map utilizing a combination of partial digestions, and cross-hybridizations. Moraxella catarrhalis, like a number of other respiratory pathogens, has a relatively small genome estimated at 1750 kilobase pairs or about 40% of the size of the Escherichia coli genome. The locations of the four ribosomal RNA operons (rrnLS) were determined by Southern hybridization and by digestion with I-CeuI endonuclease. A number of genes involved in virulence have been placed onto the physical map by Southern hybridization including those encoding the predominant outer-membrane proteins and the chromosomal gene encoding beta-lactamase.

Interleukin-1beta in immune cells of the abdominal vagus nerve: a link between the immune and nervous systems?

Intraperitoneal administration of the cytokine interleukin-1beta (IL-1beta) induces brain-mediated sickness symptoms that can be blocked by subdiaphragmatic vagotomy. Intraperitoneal IL-1beta also induces expression of the activation marker c-fos in vagal primary afferent neurons, suggesting that IL-1beta is a key component of vagally mediated immune-to-brain communication. The cellular sources of IL-1beta activating the vagus are unknown, but may reside in either blood or in the vagus nerve itself. We assayed IL-1beta protein after intraperitoneal endotoxin [lipopolysaccharide (LPS)] injection in abdominal vagus nerve, using both an ELISA and immunohistochemistry, and in blood plasma using ELISA. IL-1beta levels in abdominal vagus nerve increased by 45 min after LPS administration and were robust by 60 min. Plasma IL-1beta levels increased by 60 min, whereas little IL-1beta was detected in cervical vagus or sciatic nerve. IL-1beta-immunoreactivity (IR) was expressed in dendritic cells and macrophages within connective tissues associated with the abdominal vagus by 45 min after intraperitoneal LPS injection. By 60 min, some immune cells located within the nerve and vagal paraganglia also expressed IL-1beta-IR. Thus, intraperitoneal LPS induced IL-1beta protein within the vagus in a time-frame consistent with signaling of immune activation. These results suggest a novel mechanism by which IL-1beta may serve as a molecular link between the immune system and vagus nerve, and thus the CNS.

The impact of the nonpeptide corticotropin-releasing hormone antagonist antalarmin on behavioral and endocrine responses to stress

The nonpeptide CRH antagonist antalarmin has been shown to block both behavioral and endocrine responses to CRH. However, it's potential activity in blunting behavioral and endocrine sequelae of stressor exposure has not been assessed. Because antagonism of central CRH by alpha-helical CRH attenuates conditioned fear responses, we sought to test antalarmin in this regard. In addition, it remains unclear as to whether this is a result of receptor blockade during conditioning or during testing. Thus, we explored whether CRH mediates the induction or expression of conditioned fear (freezing in a context previously associated with 2 footshocks; 1.0 mA, 5 sec each). Furthermore, because rats previously exposed to inescapable shock (IS; 100 shocks, 1.6 mA, 5 sec each), demonstrate enhanced fear conditioning, we investigated whether this effect would be blocked by antalarmin. Antalarmin (20 mg/kg x 2 ml i.p.) impaired both the induction and expression of conditioned fear. In addition, antalarmin blocked the enhancement of fear conditioning produced by prior exposure to IS. Despite the marked behavioral effects observed in antalarmin-treated rats, antalarmin had no effect on IS-induced rises in ACTH or corticosterone. However, antalarmin did block the ACTH response produced by exposure to 2 footshocks.

Differential regulation of protease activated receptor-1 and tissue plasminogen activator expression by shear stress in vascular smooth muscle cells

Recent studies have demonstrated that vascular smooth muscle cells are responsive to changes in their local hemodynamic environment. The effects of shear stress on the expression of human protease activated receptor-1 (PAR-1) and tissue plasminogen activator (tPA) mRNA and protein were investigated in human aortic smooth muscle cells (HASMCs). Under conditions of low shear stress (5 dyn/cm2), PAR-1 mRNA expression was increased transiently at 2 hours compared with stationary control values, whereas at high shear stress (25 dyn/cm2), mRNA expression was decreased (to 29% of stationary control; P<0.05) at all examined time points (2 to 24 hours). mRNA half-life studies showed that this response was not due to increased mRNA instability. tPA mRNA expression was decreased (to 10% of stationary control; P<0.05) by low shear stress after 12 hours of exposure and was increased (to 250% of stationary control; P<0.05) after 24 hours at high shear stress. The same trends in PAR-1 mRNA levels were observed in rat smooth muscle cells, indicating that the effects of shear stress on human PAR-1 were not species-specific. Flow cytometry and ELISA techniques using rat smooth muscle cells and HASMCs, respectively, provided evidence that shear stress exerted similar effects on cell surface-associated PAR-1 and tPA protein released into the conditioned media. The decrease in PAR-1 mRNA and protein had functional consequences for HASMCs, such as inhibition of [Ca2+] mobilization in response to thrombin stimulation. These data indicate that human PAR-1 and tPA gene expression are regulated differentially by shear stress, in a pattern consistent with their putative roles in several arterial vascular pathologies.

The long term acute phase-like responses that follow acute stressor exposure are blocked by alpha-melanocyte stimulating hormone

Both intracerebroventricular (i.c.v.) IL-1beta and exposure to inescapable tail shock (IS) activate acute phase responses (APRs) that include increases in core body temperature (CBT), increases in hypothalamic-pituitary-adrenal activity, decreases in carrier proteins such as corticosterone binding globulin (CBG), aphagia and adipsia. A variety of data suggested that stressors produce APRs by inducing brain IL-1beta. The current series of studies further explored this possibility by determining whether the functional IL-1beta antagonist, alpha-melanocyte-stimulating hormone (alpha-MSH(1-13)), would block IS-induced APRs. Immediately following i.c.v. alpha-MSH(1-13) administration, rats were exposed to a single session of 100, 5 s, 1.6 mA ISs, or control treatment (home cage control). alpha-MSH(1-13) blocked IS-induced increased CBT, increased plasma corticosterone (CORT), decreased CBG, aphagia and adipsia 24 h after IS. The inhibitory effects of alpha-MSH(1-13) were shown not to be a consequence of alpha-MSH(1-13) producing its actions 24 h after its administration because alpha-MSH(1-13) given 24 h before IS did not block IS-induced increased CBT and CORT during IS. Additionally, alpha-MSH(1-13), given 24 h before IS, had no effect on increased CBT, increased CORT, decreased CBG, adipsia, or aphagia 24 h after IS. These data provide support for a specific mode of action for i.c.v. alpha-MSH(1-13), namely blockade of APRs with no impact on acute hyperthermia or increased levels of CORT produced during IS.

Acute stressor exposure both suppresses acquired immunity and potentiates innate immunity

Acute stressor exposure alters immune function. Rats exposed to inescapable tail shock stress (IS) generate less antibody to a benign, antigenic protein, keyhole limpet hemocyanin (KLH). The following studies examined the effect of IS on peritoneal cavity, spleen, and mesenteric lymph node cell number, interferon-gamma (IFN-gamma) production, and nitrite production. Rats were injected intraperitoneally with KLH (200 microg) or saline immediately before IS exposure and killed 0, 48, and 96 h after IS termination. KLH immunization resulted in elevated cell numbers and IFN-gamma levels 2-4 days later in nonstressed control rats. In contrast, rats exposed to IS failed to increase cell number and IFN-gamma levels in response to KLH. The T cell subpopulations affected were CD4 T cells, specifically the Th1-like subset. In addition, in rats exposed to IS + KLH, nitrite production was potentiated 2-4 days after stressor termination. IS had little effect on these measures in saline-injected rats. These data support the conclusion that exposure to IS suppresses the expansion of anti-KLH lymphocytes, possibly anti-KLH Th1 cells. In addition, stressor exposure potentiates the production of nitrite. Importantly, this potentiated response occurred only in KLH-immunized animals, suggesting that macrophages may be primed by stressor exposure and thus respond more vigorously to antigen. The potential links between these changes are discussed.

Exposure to acute stress induces brain interleukin-1beta protein in the rat

Peripheral immune stimulation such as that provided by lipopolysaccharide (LPS) has been reported to increase brain levels of IL-1beta mRNA, immunoreactivity, and bioactivity. Stressors produce many of the same neural and endocrine responses as those that follow LPS, but the impact of stressors on brain interleukin-1beta (IL-1beta) has not been systematically explored. An ELISA designed to detect IL-1beta was used to measure levels of IL-1beta protein in rat brain. Brain IL-1beta was explored after exposure to inescapable shock (IS; 100 1.6 mA tail shocks for 5 sec each) and LPS (1 mg/kg) as a positive control. Rats were killed either immediately or 2, 7, 24, or 48 hr after IS. Brains were dissected into hypothalamus, hippocampus, cerebellum, posterior cortex, and nucleus tractus solitarius regions. LPS produced widespread increases in brain IL-1beta, but IS did not. Adrenal glucocorticoids are known to suppress IL-1beta production in both the periphery and brain. Thus, it was possible that the stressor did provide stimulus input to the brain IL-1beta system(s), but that the production of IL-1beta protein was suppressed by the rapid and prolonged high levels of glucocorticoids produced by IS. To test this possibility rats were adrenalectomized or given sham surgery, with half of the adrenalectomized rats receiving corticosterone replacement to maintain basal corticosterone levels. IS produced large increases in brain IL-1beta protein in the adrenalectomized subjects 2 hr after stress, whether basal corticosterone levels had been maintained. Thus elimination of the stress-induced rise in corticosterone unmasked a robust and widespread increase in brain IL-1beta.

Immediate and simultaneous sensory reorganization at cortical and subcortical levels of the somatosensory system

The occurrence of cortical plasticity during adulthood has been demonstrated using many experimental paradigms. Whether this phenomenon is generated exclusively by changes in intrinsic cortical circuitry, or whether it involves concomitant cortical and subcortical reorganization, remains controversial. Here, we addressed this issue by simultaneously recording the extracellular activity of up to 135 neurons in the primary somatosensory cortex, ventral posterior medial nucleus of the thalamus, and trigeminal brainstem complex of adult rats, before and after a reversible sensory deactivation was produced by subcutaneous injections of lidocaine. Following the onset of the deactivation, immediate and simultaneous sensory reorganization was observed at all levels of the somatosensory system. No statistical difference was observed when the overall spatial extent of the cortical (9.1 +/- 1.2 whiskers, mean +/- SE) and the thalamic (6.1 +/- 1.6 whiskers) reorganization was compared. Likewise, no significant difference was found in the percentage of cortical (71.1 +/- 5.2%) and thalamic (66. 4 +/- 10.7%) neurons exhibiting unmasked sensory responses. Although unmasked cortical responses occurred at significantly higher latencies (19.6 +/- 0.3 ms, mean +/- SE) than thalamic responses (13. 1 +/- 0.6 ms), variations in neuronal latency induced by the sensory deafferentation occurred as often in the thalamus as in the cortex. These data clearly demonstrate that peripheral sensory deafferentation triggers a system-wide reorganization, and strongly suggest that the spatiotemporal attributes of cortical plasticity are paralleled by subcortical reorganization.

Quantitation of an orally available thrombin inhibitor in rat, monkey and human plasma and in human urine by high-performance liquid chromatography and fluorescent post-column derivatization of arginine

An assay for the quantification of plasma and urine levels of CVS 1123, an orally bioavailable thrombin inhibitor, and its desmethyl form. CVS 738, was developed to support clinical and toxicology studies. This assay uses solid-phase extraction, reversed-phase HPLC separation, and post-column fluorescent derivatization with ninhydrin. An internal standard is added to correct for recovery. In aqueous solution, the arginine aldehyde structures of CVS 1123 and CVS 738 exist in multiple forms which can be separated under standard reversed-phase HPLC conditions. HPLC conditions were optimized to give rapid interconversion of the forms on the separation time scale, and consequently a single chromatographic peak. Extraction conditions were modified for quantitative extraction of drug compounds from large volumes of human plasma. The assay was shown to be accurate and precise, with a quantification limit of 17 ng CVS 1123/ml human plasma.