Mucosal Vessels (mucosal + vessel)

Distribution by Scientific Domains

Selected Abstracts

Bridging Mucosal Vessels Associated with Rhythmically Oscillating Blood Flow in Murine Colitis

Aslihan Turhan
Abstract Oscillatory blood flow in the microcirculation is generally considered to be the result of cardiopulmonary influences or active vasomotion. In this report, we describe rhythmically oscillating blood flow in the bridging vessels of the mouse colon that appeared to be independent of known biological control mechanisms. Corrosion casting and scanning electron microscopy of the mouse colon demonstrated highly branched bridging vessels that connected the submucosal vessels with the mucosal plexus. Because of similar morphometric characteristics (19 11 ,m vs. 28 16 ,m), bridging arterioles and venules were distinguished by tracking fluorescent nanoparticles through the microcirculation using intravital fluorescence videomicroscopy. In control mice, the blood flow through the bridging vessels was typically continuous and unidirectional. In contrast, two models of chemically induced inflammation (trinitrobenzenesulfonic acid and dextran sodium sulfate) were associated with a twofold reduction in flow velocity and the prominence of rhythmically oscillating blood flow. The blood oscillation was characterized by tracking the bidirectional displacement of fluorescent nanoparticles. Space,time plots and particle tracking of the oscillating segments demonstrated an oscillation frequency between 0.2 and 5.1 cycles per second. Discrete Fourier transforms demonstrated a power spectrum composed of several base frequencies. These observations suggest that inflammation-inducible changes in blood flow patterns in the murine colon resulted in both reduced blood flow velocity and rhythmic oscillations within the bridging vessels of the mouse colon. Anat Rec, 291:74,82, 2007. 2007 Wiley-Liss, Inc. [source]

Effects of long-term cyclo-oxygenase 2 selective and acid inhibition on Barrett's oesophagus

Summary Background There is an overexpression of cyclo-oxygenase 2 (COX-2) in Barrett's oesophagus (BO). Aim To determine the long-term effect of a COX-2 inhibitor on cellular mechanisms involved in BO. Methods A randomized controlled trial was conducted in BO patients allocated to continue the usual proton pump inhibitor (PPI) alone treatment, or PPI combined with rofecoxib (25 mg/day) for 6 months. Cell proliferation index and COX-2 expression in BO glands was determined in biopsy specimens at baseline and after treatment. Cell apoptosis, cyclin D1, p53 and vascular endothelial growth factor (VEGF) expression was also explored in a subset of patients. Student- t test and the U-Mann,Whitney test were used for quantitative and ordinal variables. Results Of 62 patients, 58 completed the study. A higher proportion of patients on rofecoxib + PPI exhibited a decrease in COX-2 expression compared to those treated with PPI alone, but cell proliferation index was not affected. Unlike PPI alone, rofecoxib + PPI was associated with an increase in the apoptotic cell index, a decrease in p53 cell staining and VEGF expression in mucosal vessels. No effect on low-grade dysplasia or cyclin D1 was observed. Conclusions The addition of rofecoxib to PPI therapy does not affect cell proliferation index in BO cells after 6 months of therapy, but does reduce COX-2 and VEGF expression and increases cell apoptosis. [source]

Bimodal Oscillation Frequencies of Blood Flow in the Inflammatory Colon Microcirculation

Akira Tsuda
Abstract Rhythmic changes in blood flow direction have been described in the mucosal plexus of mice with acute colitis. In this report, we studied mice with acute colitis induced either by dextran sodium sulfate or by trinitrobenzenesulfonic acid. Both forms of colitis were associated with blood flow oscillations as documented by fluorescence intravital videomicroscopy. The complex oscillation patterns suggested more than one mechanism for these changes in blood flow. By tracking fluorescent nanoparticles in the inflamed mucosal plexus, we identified two forms of blood flow oscillations within the inflammatory mouse colon. Stable oscillations were associated with a base frequency of approximately 2 cycles/sec. Velocity measurements in the upstream and downstream vessel segments indicated that stable oscillations were the result of regional flow occlusion within the mucosal plexus. In contrast, metastable oscillations demonstrated a lower frequency (0.2,0.4 cycles/sec) and appeared to be the result of flow dynamics in vessels linked by the bridging mucosal vessels. These blood flow oscillations were not directly associated with cardiopulmonary movement. We conclude that both the stable and metasable oscillating patterns reflect flow adaptations to inflammatory changes in the mucosal plexus. Anat Rec, 2009. 2008 Wiley-Liss, Inc. [source]

Hypertonic saline nasal provocation and acoustic rhinometry

J. N. Baraniuk
Summary Background Hypertonic saline (HTS) acts as an airway irritant in human nasal mucosa by stimulating nociceptive nerves and glandular secretion. HTS does not change vascular permeability. In asthma, HTS causes airflow obstruction. Objective To determine the effect of HTS on mucosal swelling using acoustic rhinometry (AcRh). Potential vasodilator effects were controlled by maximally constricting mucosal vessels with oxymetazoline (Oxy). Method Normal subjects had AcRh before and 30 min after either 0.05% Oxy or saline (0.9% NaCl) nasal treatments. Nasal provocations followed immediately with five step-wise incremental escalating doses of HTS administered at 6-min intervals. AcRh was performed 1, 3 and 5 min after each HTS administration, and then after blowing the nose at 5 min. The minimum cross-sectional area (Amin), volume of the anterior 6 cm of nasal cavity (V6) and incremental changes from pre-drug treatment baseline levels (,, mean ,SEM) were calculated. Results Oxy increased Amin by 46% (, = 0.48 0.07 cm2, P = 0.0001) and V6 by 53% (, = 9.9 1.5 mL, P < 1 10,7) during the first 30 min. Saline (vehicle) treatment had no effect. The maximum HTS dose had no effect after 1 or 3 min. However, in the 4th and 5th minutes there were reductions in Amin (, = 0.07 0.03 cm2, P = 0.035) and V6 (, = 1.57 0.42 mL, P = 0.004) with an increase in the weight of secretions (, = 700 100 mg, P < 0.05). Blowing the nose returned Amin and V6 towards baseline. Oxy had no effect on HTS-induced changes in Amin, V6, pain, rhinorrhea or weight of secretions. Conclusion HTS induced nociceptive nerve stimulation and mucus secretion, and reduced V6 and Amin. Oxy caused vasoconstriction but did not alter HTS-induced effects. HTS may stimulate neurogenic axon response-mediated glandular secretion that contributes to perceptions of nasal obstruction in normal subjects. [source]