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Q X Wang

Publications and source records attributed to Q X Wang.

8 recordsLinked to original sources
PubMed2005

Stellate ganglion block inhibits formalin-induced nociceptive responses: mechanism of action.

BACKGROUND AND OBJECTIVE: Stellate ganglion block has been extensively used in clinical practice for the management of painful conditions such as cephalic, facial and upper limb pains yet its mechanism of action and its analgesic efficacy are poorly understood. METHOD: Formalin (3% 0.2 mL) was injected into the plantar region of the right upper limb paw in rabbits and 50 min after this injection, saline or bupivacaine 2.5% 0.5 mL was administered via a chronic implantation catheter near the right stellate ganglion. Behavioural modification, changes in heart rate and plasma norepinephrine release at different time points after formalin and bupivacaine or saline injection were observed. Finally, the cervical spinal cord was harvested and immunostaining for substance P and c-Fos was performed. RESULTS: Formalin caused stress noxious behavioural changes and a significant increase in heart rate and norepinephrine release. These changes were inhibited by bupivacaine stellate ganglion block but not by saline injection. Immunoreactants of substance P were significantly decreased by formalin injection compared with that in controls. However, with bupivacaine injection, substance P levels were restored though not reaching the levels seen in the controls. Formalin injection also caused a significant increase of c-Fos expression in cervical spinal cord. This increase was not affected by stellate ganglion block. CONCLUSION: Stellate ganglion block can effectively alleviate nociceptive responses induced by formalin injection. The mechanism of its action may involve reduction of substance P in the spinal cord and plasma catecholamine release caused by noxious stimuli.

Analgesia↗
PubMed2003

Constitutive model development and micro-structural topology optimisation for nafion hydrogel membranes with ionic clustering.

The deployment of electroactive ionic polymer hydrogel-metal composites in artificial muscle and BioMEMS applications has recently been intensively investigated. In order to analyse their electromechanical responses to externally applied electrical fields, it is critical to develop a constitutive model linking the macro-mechanical moduli with the micro-mechanical characteristics, and to determine the geometric size and shape of the micro-structural cluster and investigate the effect of cluster morphology on the effective electro-elastic moduli of the polymer hydrogels. As a typical ionic polymer-based hydrogel, the Nafion membrane is studied in this work. Based on the Biot poroelasticity theory, a multi-scale constitutive model which includes both macro and micro characteristics is developed using an asymptotic homogenisation method. The effect of water-volume fraction on the effective elastic moduli of the hydrogel membrane is examined for different equivalent weights. Numerical investigations show that the simulated effective constitutive moduli agree well with experimental data. The presently developed constitutive model is thus validated. In order to determine the micro-structural shape of the polymer skeleton subject to fluid pressure, a representative volume element (RVE) is designed by topology optimisation of the periodic microstructures of the Nafion hydrogels, through the minimisation of the electro-elastic interaction energy between the polymer-based fluorocarbon matrix and the surrounding fluid. This optimal RVE correctly predicts the geometric shapes of the clusters.

Compressive Strength↗
PubMed1997

Organization of the blood and lymphatic microvasculature of the gallbladder in the guinea pig: a scanning electron microscopic study.

The organization of the blood and lymphatic microvessels of the gallbladder in the guinea pig is demonstrated by scanning electron microscopy (SEM) of vascular corrosion casts, and SEM of KOH-macerated tissues. In the lamina propria of the gallbladder, there is a dense network of subepithelial capillaries. The network is supplied by the arterioles that come off the arterial plexus located deep in the lamina propria. The network gathers into the postcapillary venules continuous with the collecting venular plexus located immediately below the subepithelial capillary network. The precapillary arterioles are sparsely surrounded by a single layer of circularly oriented extensions of smooth muscle cells. The terminal arterioles are endowed with circularly oriented fusiform smooth muscle cells. The nervous plexus is also noticed along the terminal arterioles. The capillaries are embraced by flat prolongations of pericytes. The postcapillary venules are sparsely surrounded by stellate pericytes and the collecting venules are sparsely surrounded by elongated or branched spindle-shaped, primitive smooth muscle cells which extend their long process in various directions along the vascular wall. The lymphatics are mostly located in the subserosal layer. The tips of the initial lymphatics are closed by endothelial cells, although there are frequently some gaps between them. The thin flaps of the lymphatic endothelial cells overlap or interdigitate with each other. The luminar surfaces of the lymphatics show oval nuclear protrusions, while the abluminal surfaces showed numerous microfolds except for the oval and flat nuclear portions. The lymphatics possess neither smooth muscle cells nor pericytes.

Animals↗
PubMed1997

Distribution and ultrastructure of the stomata connecting the pleural cavity with lymphatics in the rat costal pleura.

We investigated the detailed distribution and ultrastructure of the stomata connecting the pleural cavity and the lymphatics in the rat costal pleura by scanning electron, transmission electron and light microscopy. The mesothelial cells lining the costal pleura appeared as both flattened and thick cell bodies. The thick cells possessed more rough endoplasmic reticula, Golgi complexes, mitochondria, and free ribosomes than the flattened cells. The thick cells were distributed in the intercostal regions each cephalic to the junction of the costal cartilage and bone, and in the band-like regions along the cephalic and caudal sides of each rib in the lateral and dorsal thoracic walls. In the regions lined with thick cells, there were stomata [12.9 +/- 10.3 microns2 (mean +/- SD) in area] consisting of prolongations of thick mesothelial cells and funnel-like projections of lymphatic endothelial cells that came up along the rims of the pores (5.9 +/- 3.2 microns2 in average area) in the submesothelial collagen fiber network. At the stomata, the basal lamina of the mesothelium was continuous with that of the endothelium. The mesothelial cells forming the stomata were mostly in close contact with the endothelial cells, but some gaps also existed between them. Valve-like endothelial flaps were frequently observed wherever endothelial cells constituting the stomata merged into the submesothelial lymphatics. Also present were lymphatic bulges that were either in close contact with the base of the thick mesothelial cells or exposed through the mesothelial pores. The lymphatic network was especially well developed in the submesothelial layer at and around the thick-cell regions. The initial lymphatics drained into the intercostal collecting lymphatics, which in turn led into either the parasternal or paravertebral lymphatic trunk. Our results suggest that the stomata play a major role in absorbing fluids and particulates in the pleural cavity. The thick mesothelial cells appear to secrete chemotactic substances to the endothelial cells. Understanding the heterogeneous distribution of the stomata could prove to be important clinically in inflammatory diseases and tumors in the chest.

Animals↗
PubMedDate not supplied

Comparative analysis of insulo-acinar portal system in rats, guinea pigs, and dogs.

The insulo-acinar portal system in the rat, guinea pig, and dog was comparatively analyzed using corrosion casting method in scanning electron microscopy and confocal laser scanning microscopy. In all animals examined, there were three types of arterioles according to their destination: 1) the arteriole which supplied the capillary glomerulus of the islet, 2) the arterioles which directly branched out into capillaries around the acini, and 3) the arterioles which supplied the duct system. In the rat, the afferent vessel usually ended in the cortical layer of the islet and its main branches ran along this layer before giving secondary capillary branches into the deeper regions, while in the dog and guinea pig, the region where the afferent arterioles branched out into secondary capillary branches varied among individual islets. There were three types of efferent vessels of the islet: 1) the insulo-acinar portal vessels that radiated from the islet to join the capillary network in the exocrine pancreas, 2) the emissary venules of the islet, leading directly into the systemic circulation, and 3) the insulo-ductal portal vessels which drained into the peri-ductal capillary network. In the rat and guinea pig, the intralobular islets possessed both the insulo-acinar portal vessels and the emissary venules, while the interlobular islets possessed emissary venules with occasionally occurring insulo-acinar portal vessels. In the dog, most of the islets were located within the lobule and possessed preferentially the insulo-acinar portal vessels. In this animal, the lobule was supplied by several microvascular units, in the center of which was located the capillary glomerulus of the islet. The peri-insular zone of the unit was mainly supplied by the insulo-acinar portal vessels, while the periphery, the tele-insular zone, was directly supplied by arterioles as well. The venules originated at the periphery of the unit. The islet in the dog had virtually no emissary venules. Confocal laser scanning microscopy of the rat islets showed that B cells occupied the core of all islets. The microvascular architecture within the rat islet appeared to be organized as to drain blood from the A and D cell area to the B cell area of the islet.

Animals↗