The selective protection afforded by ebselen against lipid peroxidation in an ROS-dependent model of inflammation

The effects of an experimental model of hydrogen-peroxide-induced foot pad oedema on indices of oxidative damage to biomolecules have been investigated. We have demonstrated increased levels of fluorescent protein and lipid peroxides occurring in plasma at 24 and 48 h post-injection. In addition, a decrease in the degree of galactosylation of IgG was observed which kinetically related the degree of inflammation and to the increase in protein autofluorescence (a specific index of oxidative damage). The effects of ebselen, a novel organoselenium compound which protects against oxidative tissue injury in a glutathione-peroxidase-like manner, have also been examined in this model. Pretreatment of animals with a dose of 50 mg/kg ebselen afforded significant and selective protection against lipid peroxidation only. This effect may contribute to the anti-inflammatory effect of this agent in hydroperoxide-linked tissue damage.

Reducing suffering in experimental autoimmune encephalomyelitis (EAE)

This report is based on discussions and submissions from an expert working group consisting of veterinarians, animal care staff and scientists with expert knowledge relevant to the field. It aims to facilitate the implementation of the Three Rs (replacement, reduction and refinement) in the use of animal models or procedures involving experimental autoimmune encephalomyelitis (EAE), an experimental model used in multiple sclerosis research. The emphasis is on refinement since this has the greatest potential for immediate implementation. Specific welfare issues are identified and discussed, and practical measures are proposed to reduce animal use and suffering. Some general issues for refinement are summarised to help achieve this, with more detail provided on a range of specific measures to reduce suffering. © 2013 Elsevier Inc.

Monocyte urokinase-type plasminogen activator up-regulation reduces thrombus size in a model of venous thrombosis

Background - Our previous studies showed that the direct injection of an adenovirus construct expressing urokinase-type plasminogen activator (uPA) into experimental venous thrombi significantly reduces thrombus weight. The systemic use of adenovirus vectors is limited by inherent hepatic tropism and inflammatory response. As macrophages are recruited into venous thrombi, it is reasonable to speculate that these cells could be used to target the adenovirus uPA (ad-uPA) gene construct to the thrombus. The aims of this study were to determine whether macrophages transduced with ad-uPA have increased fibrinolytic activity and whether systemic injection of transduced cells could be used to target uPA expression to the thrombus and reduce its size. Methods - The effect of up-regulating uPA was examined in an immortalized macrophage cell line (MM6) and macrophages differentiated from human blood monocyte-derived macrophages (HBMMs). Cells were infected with ad-uPA or blank control virus (ad-blank). Fibrinolytic mediator expression, cell viability, and cytokine expression were measured by activity assays and enzyme-linked immunosorbent assays. Monocyte migration was measured using a modified Boyden chamber assay. A model of venous thrombosis was developed and characterized in mice with severe combined immunodeficiency (SCID). This model was used to study whether systemically administered macrophages over-expressing uPA reduced thrombus size. Uptake of HBMMs into the thrombus induced in these mice was confirmed by a combination of PKH2-labeled cell tracking and colocalization with human leukocyte antigen (HLA) by immunohistology. Results - Compared with ad-blank, treated HBMMs transduction with ad-uPA increased uPA production by >1000-fold (P = .003), uPA activity by 150-fold (P = .0001), and soluble uPA receptor (uPAR) by almost twofold (P = .043). Expression of plasminogen activator inhibitor (PAI-1) and PAI-2 was decreased by about twofold (P = .011) and threefold (P = .005), respectively. Up-regulation of uPA had no effect on cell viability or inflammatory cytokine production compared with ad-blank or untreated cells. Ad-uPA transduction increased the migration rate of HBMMs (about 20%, P = .03) and MM6 cells (>twofold, P = .005) compared with ad-blank treated controls. Human macrophage recruitment into the mouse thrombus was confirmed by the colocalization of HLA with the PKH2-marked cells. Systemic injection of uPA-up-regulated HBMMs reduced thrombus weight by approximately 20% compared with ad-blank (P = .038) or sham-treated controls (P = .0028). Conclusion - Transduction of HBBM with ad-uPA increases their fibrinolytic activity. Systemic administration of uPA up-regulated HBBMs reduced thrombus size in an experimental model of venous thrombosis. Alternative methods of delivering fibrinolytic agents are worth exploring.

Histaminergic modulation in Tourette syndrome

Introduction: Tourette syndrome is a neurodevelopmental disorder characterized by multiple motor tics and at least one vocal/phonic tic. Clinical phenotypes show a wide variability, often incorporating behavioral symptoms. The exact pathophysiology of Tourette syndrome is unknown, however genetic vulnerability and alterations in dopaminergic neurotransmission have consistently been reported. Other biochemical pathways, including histaminergic neurotransmission, are likely to be involved but have received relatively little attention until recently. Areas covered: We conducted a systematic literature review focusing on the role of histaminergic neurotransmission and its pharmacological modulation in Tourette syndrome. We identified a number of relevant original studies published over the last five years, mainly focusing on genetic aspects. Expert opinion: There is converging evidence from recent studies supporting the hypothesis that histaminergic neurotransmission may play a role in the pathophysiology of Tourette syndrome. Most studies focused on the role of the histidine decarboxylase gene and the potential usefulness of histidine decarboxylase knockout mice as an experimental model for studying neurochemical function in Tourette syndrome. There have been no large scale studies assessing the use of histaminergic medications in the management of Tourette syndrome. This would be an important area for future research, with direct implications for the clinical management of selected phenotypes.

The isolation and identification of dermatologically active constituents of coal tar

The production and uses of coal tar are reviewed as are the uses of steroids and cytotoxic agents in the treatment of psoriasis with a review of the condition also. An attempt was made to improve the efficaciousness and cosmetic acceptability of a low temperature tar, by screening fractions of this tar, derived from a variety of separation procedures. The most efficacious fraction was the highest boiling acid fraction, which is believed to consist mainly of mono- and di-hydric phenols. A time and concentration study showed that the optimum regime was the application of a 10% concentration in 5% wool fat in soft, yellow paraffin daily for 21 days. The mouse tail skin was selected as an experimental model, to ascertain the efficaciousness of fractions, because of the similarities between this skin and the psoriatic lesion. The activity of a fraction was monitored by the inducement of a granular layer in the mouse tail epidermis. Because coal tar is not an easy medium to work with, and the active fractions showed no increase in cosmetic acceptability over the parent coal tar, likely coal tar constituents were selected for screening on the basis of phenolic character, and the molecular weight range elucidated by mass spectroscopy. 32 potential anti-psoriatic agents were screened on mouse tail. Two catechols, 3,5-di-t-butyl and 4-t-butyl catechols were active. Other structures showed little or no activity. 24 catechols were screened and two extremely active catechols were discovered, 3-methyl-5-t-octyl and 5-methyl-3-t-octyl catechols. The screening of catechol-rich coal tar fractions and a coal tar fraction which had had the catechols removed by oxidation, showed that some anti-psoriatic activity was contained in the catechol fraction of coal tar. Attempts to elucidate the mode of action of these two compounds met with little success, but two modes of action are suggested.

Adrenoceptors and intestinal fluid and electrolyte transport in the rat

Noradrenaline was found to significantly stimulate fluid and Na absorption across everted sacs of rat jejunum. Of a number of a1, and 2-adrenoceptor antagonists tested only prazosin significantly inhibited the stimulant effect of noradrenaline and further experiments revealed an antiabsorptive effect of prazosin alone. Theophylline reduced jejunal fluid and Na absorption and this effect was not reversed by 2-adrenoceptor stimulation in contrast to previous findings in vivo. Evidence suggests the everted sac preparation is not appropriate to the study of intestinal fluid and electrolyte transport. The investigation of Jejunal ion transport in vitro was continued using an Ussing chamber preparation. Selective 2-adrenoceptor stimulation was found to depress electrogenic anion secretion, as neurotoxin tetrodotoxin indicated that this was a direct epithelial effect. 2-adrenoceptor agonists have considerable therapeutic value as antisecretory agents and the model of rat jejunum in vitro represents a convenient experimental model for research in this area. The selective 2-adrenoceptor antagonist ICI 118551 decreased basal SCC and inhibited increases in SCC in response to isoprenaline or salbutamol indicating the presence of a 2-adrenoceptor mechanism mediating both secretory tone and increases in secretory processes. Many intestinal secretagogues elicit electrolyte secretion via the stimulation of intramural secretory nervous pathways. If these pathways involve the activation of 2-adrenoceptorsthe 2-adrenoceptor antagonists may be useful in the treatment of diarrhoeal diseases. A single pass lumen perfusion technique was used to investigate possible sympathetic tone over colonic fluid and electrolyte absorption in the rat colon in vivo. The technique employed appeared to lack the necessary resolution for this study and alternative approaches are discussed

Metabolic and morphological alterations induced by proteolysis-inducing factor from Walker tumour-bearing rats in C2C12 myotubes

BACKGROUND: Patients with advanced cancer suffer from cachexia, which is characterised by a marked weight loss, and is invariably associated with the presence of tumoral and humoral factors which are mainly responsible for the depletion of fat stores and muscular tissue. METHODS: In this work, we used cytotoxicity and enzymatic assays and morphological analysis to examine the effects of a proteolysis-inducing factor (PIF)-like molecule purified from ascitic fluid of Walker tumour-bearing rats (WF), which has been suggested to be responsible for muscle atrophy, on cultured C2C12 muscle cells. RESULTS: WF decreased the viability of C2C12 myotubes, especially at concentrations of 20-25 mug.mL-1. There was an increase in the content of the pro-oxidant malondialdehyde, and a decrease in antioxidant enzyme activity. Myotubes protein synthesis decreased and protein degradation increased together with an enhanced in the chymotrypsin-like enzyme activity, a measure of functional proteasome activity, after treatment with WF. Morphological alterations such as cell retraction and the presence of numerous cells in suspension were observed, particularly at high WF concentrations. CONCLUSION: These results indicate that WF has similar effects to those of proteolysis-inducing factor, but is less potent than the latter. Further studies are required to determine the precise role of WF in this experimental model. © 2008 Yano et al; licensee BioMed Central Ltd.

Probabilistic multiple model neural network based leak detection system:experimental study

This paper presents an effective decision making system for leak detection based on multiple generalized linear models and clustering techniques. The training data for the proposed decision system is obtained by setting up an experimental pipeline fully operational distribution system. The system is also equipped with data logging for three variables; namely, inlet pressure, outlet pressure, and outlet flow. The experimental setup is designed such that multi-operational conditions of the distribution system, including multi pressure and multi flow can be obtained. We then statistically tested and showed that pressure and flow variables can be used as signature of leak under the designed multi-operational conditions. It is then shown that the detection of leakages based on the training and testing of the proposed multi model decision system with pre data clustering, under multi operational conditions produces better recognition rates in comparison to the training based on the single model approach. This decision system is then equipped with the estimation of confidence limits and a method is proposed for using these confidence limits for obtaining more robust leakage recognition results.

Experimental validation of a predictive pyrolysis model in AspenPlus®

A novel simulation model for pyrolysis processes oflignocellulosicbiomassin AspenPlus (R) was presented at the BC&E 2013. Based on kinetic reaction mechanisms, the simulation calculates product compositions and yields depending on reactor conditions (temperature, residence time, flue gas flow rate) and feedstock composition (biochemical composition, atomic composition, ash and alkali metal content). The simulation model was found to show good correlation with existing publications. In order to further verify the model, own pyrolysis experiments in a 1 kg/h continuously fed fluidized bed fast pyrolysis reactor are performed. Two types of biomass with different characteristics are processed in order to evaluate the influence of the feedstock composition on the yields of the pyrolysis products and their composition. One wood and one straw-like feedstock are used due to their different characteristics. Furthermore, the temperature response of yields and product compositions is evaluated by varying the reactor temperature between 450 and 550 degrees C for one of the feedstocks. The yields of the pyrolysis products (gas, oil, char) are determined and their detailed composition is analysed. The experimental runs are reproduced with the corresponding reactor conditions in the AspenPlus model and the results compared with the experimental findings.