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Maximal Change (maximal + change)
Selected AbstractsComparison of glucocorticoid and cysteinyl leukotriene receptor antagonist treatments in an experimental model of chronic airway inflammation in guinea-pigsCLINICAL & EXPERIMENTAL ALLERGY, Issue 1 2004E. A. Leick-maldonado Abstract Background Leukotriene receptor antagonists have been demonstrated in several studies to possess bronchodilating and anti-inflammatory properties in asthma. However, there are few experimental studies performed to compare the effects of anti-leukotrienes and glucocorticoids, most used anti-inflammatory agents in asthma. In the present study, we evaluated the effects of treatment with dexamethasone or montelukast on eosinophil and mononuclear cell recruitment in an experimental model of allergen-induced chronic airway inflammation in guinea-pigs (GP). Methods GP were submitted to increasing concentrations of aerosols of ovalbumin (OVA) twice a week for 4 weeks. After 2 weeks, animals were treated daily with dexamethasone, montelukast or saline solution. After this period, GP were anaesthetized, tracheostomized, mechanically ventilated and challenged with OVA aerosol. Results Maximal changes of respiratory system resistance and elastance induced by OVA challenge were attenuated by dexamethasone (P<0.001), but not by montelukast treatment. Neither dexamethasone nor montelukast significantly influenced bronchial oedema formation. Dexamethasone but not montelukast induced a decrease in mononuclear cells in airways (P<0.001). Eosinophil infiltration in the bronchial wall was reduced by both dexamethasone and montelukast (P<0.005). Only dexamethasone treatment reduced the levels of exhaled nitric oxide (P<0.025). Conclusion Although leukotriene receptor antagonist treatment reduces eosinophil accumulation induced by multiple antigen challenges, glucocorticoid treatment attenuates both eosinophil and mononuclear cell infiltration. [source] Intravenous and intratracheal administration of trimetoquinol, a fast-acting short-lived bronchodilator in horses with ,heaves'EQUINE VETERINARY JOURNAL, Issue 6 2006F. C. CAMARGO Summary Reason for performing study: Trimetoquinol (TMQ) is a potent ,-adrenoceptor agonist bronchodilator used in human medicine but has not been evaluated for potential use as a therapeutic agent for horses with ,heaves'. Objectives: To assess the pharmacodynamics of TMQ in horses with ,heaves' to determine potential therapeutic effects. Methods: Increasing doses of TMQ were administered to horses with ,heaves' by i.v. and intratracheal (i.t.) routes. Doses ranged 0.001,0.2 ,g/kg bwt i.v. and 0.01,2 ,g/kg bwt i.t. Cardiac and airways effects were assessed by measurement of heart rate (HR) and maximal change in pleural pressure (,Pplmax), respectively. Side effects of sweating, agitation and muscle trembling were scored subjectively. Duration of action to i.v. (0.2 ,g/kg bwt) and i.t. (2 ,g/kg bwt) TMQ was evaluated over 6 h. Results: Intravenous TMQ was an exceptionally potent cardiac stimulant. Heart rate increased at 0.01 ,g/kg bwt, and was still increasing after administration of highest dose, 0.2 ,g/kg bwt. Airway bronchodilation, measured as a decrease in ,Pplmax, also commenced at 0.01 ,g/kg bwt. By the i.t. route, TMQ was 50,100-fold less potent than by i.v. Side effects included sweating, agitation and muscle trembling. Overall, the onset of HR and bronchodilator effects was rapid, within about 3 min, but effects were over at 2 h. Conclusion: When administered i.v. and i.t., TMQ is a highly potent cardiac stimulant and a modest bronchodilator. It may not be an appropriate pharmacological agent by i.v. and i.t. routes for the alleviation of signs in horses with ,heaves'. Further studies of TMQ by oral and aerosol routes are necessary. Potential relevance: In horses, TMQ is a fast-acting bronchodilator with a short duration of action. It could be used as a rescue agent during an episode of ,heaves'. The i.v. and i.t. administration of TMQ is associated with side effects, similar to those reported for all other ,-agonists. However, other routes, such as aerosol and oral, may prove useful and safe for the alleviation of bronchoconstriction typical of ,heaves'. [source] Functional protease-activated receptors in the dorsal motor nucleus of the vagusNEUROGASTROENTEROLOGY & MOTILITY, Issue 4 2010H. Wang Abstract Background, Protease-activated receptors (PARs), a family member of G-protein coupled receptors, are present and functionally active in a wide variety of cells. The object of this study was to demonstrate the presence and function of PAR-1 and PAR-2 in the dorsal motor nucleus of the vagus (DMV). Methods, DMNV neurons were isolated from neonatal rat brainstems using micro-dissection and enzymatic digestion. Neurons were cultured in Neurobasal medium A containing 2% B27 supplement. Intracellular calcium concentration ([Ca2 + ]i) was measured using fura-2 based microspectrometry. Expression of PARs was detected by RT-PCR and immunofluorescent staining. Key Result, Thrombin and PAR-1 agonist peptide activate PAR-1 with a maximum change in [Ca2 + ]i expressed as ,F/F0 of 229 ± 14% and 137 ± 7%, respectively. Trypsin and PAR-2 agonist peptide activate PAR-2 with a maximum ,F/F0 change of 258 ± 12% and 242 ± 10%, respectively. Inhibition of phospholipase C (PLC) by U73312 (1 ,m) decreased the maximal change in ,F/F0 induced by PAR-1 activation from 140 ± 17% to 21 ± 3%, while the PAR-2-mediated maximal change in ,F/F0 decreased from 185 ± 21% to 19 ± 6%. Blockade of IP3 receptor with 2APB inhibited the maximal change in ,F/F0 due to PAR-1 and PAR-2 activation by 72 ± 13% and 71 ± 20% respectively. PAR-1 immnuoreactivity was present in DMV neurons. Increase in transcripts for PAR-1 and PAR-2 were detected in DMV tissues derived from IBD rats relative to control animals. Conclusions & Inferences, Our results indicate that PAR-1 and PAR-2 are present in the DMV neurons, and their activation leads to increases in intracellular calcium via signal transduction mechanism that involves activation of PLC and the production of IP3. [source] Correlation of the development of knee pain with enlarging bone marrow lesions on magnetic resonance imagingARTHRITIS & RHEUMATISM, Issue 9 2007David T. Felson Objective Results of cross-sectional studies have suggested that bone marrow lesions (BMLs) visualized on magnetic resonance imaging (MRI) are related to knee pain, but no longitudinal studies have been done. This study was undertaken to determine whether enlarging BMLs are associated with new knee pain. Methods Subjects ages 50,79 years with knee osteoarthritis (OA) or at high risk of knee OA were asked twice at baseline about the presence of knee pain, aching, or stiffness (classified as frequent knee pain) on most days; absence of knee pain was the baseline eligibility criterion. At 15 months' followup, subjects were again queried twice about frequent knee pain. A case knee was defined as absence of knee pain at baseline but presence of knee pain both times at followup. Controls were selected randomly from among knees with absence of pain at baseline. All MR images were scored for volume of BMLs in the medial, lateral, and patellofemoral compartments. We focused on the maximal change in BML score among the knee compartments from baseline to 15 months. Multiple logistic regression, with adjustments for demographic and clinical variables, was used to assess whether an increased BML score is predictive of the development of knee pain. Results Among case knees, 54 of 110 (49.1%) showed an increase in BML score within a compartment, whereas only 59 of 220 control knees (26.8%) showed an increase (P < 0.001 by chi-square test). A BML score increase of at least 2 units was much more common in case knees than in control knees (27.5% versus 8.6%; adjusted odds ratio 3.2, 95% confidence interval 1.5,6.8). Among case knees with increased BMLs, most already had BMLs at baseline, with enlarging BMLs at followup, but among the subset of knees with no BMLs at baseline, new BMLs were more common in case knees (11 [32.4%] of 34) than in control knees (9 [10.8%] of 83). Conclusion Development of knee pain is associated with an increase in BMLs as revealed on MRI. [source] An investigation of the relationship between hullability and morphological features in grains of four oat varietiesANNALS OF APPLIED BIOLOGY, Issue 2 2010E. White Milling of oats involves separation of the kernel from its enclosing husk. The ease with which this happens is termed ,hullability'. The association between morphological characteristics measured using image analysis and hullability was examined in oat varieties sampled from Recommended List variety trials conducted at AFBI Crossnacreevy, Belfast, UK in 2000 and 2006. Grain features of the varieties were distinctive and showed differing relationships with weight, Barra changing only slightly, whilst Mascani showed the maximal changes with increasing grain weight. Hullability was poorer in larger grain, and better in Barra and Mascani than in Gerald and Tardis. Fitting of exponential models for the percentage of hulled grain with dehulling duration identified features associated with different aspects of dehulling behaviour. Greater width of grains of Mascani and Tardis was associated with a more rapid increase in hullability at shorter durations of dehulling. Greater roundness in Barra and Gerald in 2000 was associated with better hullability at very short durations of dehulling relative to other varieties. It is concluded that these features of the grain could be of use in selecting high hullability in breeding programmes. [source] Relationship between muscle oxygenation and electromyography activity during sustained isometric contractionCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 4 2008Eiji Yamada Summary The purpose of this study was to clarify the relationship between electromyography (EMG) spectrum changes and muscle oxygenation measured by near-infrared time-resolved spectroscopy (TRS). Each subject performed sustained isometric knee extension at 50% of the maximal voluntary contraction load for 1 min. Surface EMG and TRS were simultaneously recorded from the right vastus lateralis muscle. Mean power frequency (MPF) of the power spectrum was calculated every 5 s during isometric contraction using fast Fourier transform, and decrease in the slope of MPF for 1 min was calculated using the least squares method. The maximal changes in oxygenated haemoglobin and myoglobin (Oxy Hb/Mb) and in deoxygenated haemoglobin and myoglobin (Deoxy Hb/Mb) from pre-contraction values of 1 min were calculated. There were significant relationships between the decrease in the slope of MPF and the maximal changes in Oxy Hb/Mb and Deoxy Hb/Mb (P < 0·05). These findings suggested that changes in Oxy Hb/Mb and Deoxy Hb/Mb indicate muscle fatigue assessed by EMG. [source] | ||||||||||