Home About us Contact
|
Home About us Contact | ||
|
|
||
Smooth Muscle Tissue (smooth + muscle_tissue)
Selected AbstractsExpression pattern of Popdc2 during mouse embryogenesis and in the adultDEVELOPMENTAL DYNAMICS, Issue 3 2008Alexander Froese Abstract The Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life. Developmental Dynamics 237:780,787, 2008. © 2008 Wiley-Liss, Inc. [source] Hamartoma of the breastJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 2007A Murat SUMMARY Breast hamartoma is a rare benign tumour that leads to unilateral breast enlargement without a palpable localized mass lesion. Histologically, a hamartoma consists of varying amounts of adipose, gland, fibre and smooth muscle tissue. The characteristic mammographic appearance of hamartoma of breast has distinct mammographic features with circumscription and fat and soft-tissue density surrounded by a thin radiopaque capsule or pseudocapsule. Ultrasonographic findings include a well-defined mass lesion consisting of echogenic and sonolucent areas. We present histopathological and radiological findings of a 42-year-old female patient with breast hamartoma who has no complaint. [source] Evidence of innervation following extracellular matrix scaffold-mediated remodelling of muscular tissuesJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 8 2009Vineet Agrawal Abstract Naturally occurring porcine-derived extracellular matrix (ECM) has successfully been used as a biological scaffold material for site-specific reconstruction of a wide variety of tissues. The site-specific remodelling process includes rapid degradation of the scaffold, with concomitant recruitment of mononuclear, endothelial and bone marrow-derived cells, and can lead to the formation of functional skeletal and smooth muscle tissue. However, the temporal and spatial patterns of innervation of the remodelling scaffold material in muscular tissues are not well understood. A retrospective study was conducted to investigate the presence of nervous tissue in a rat model of abdominal wall reconstruction and a canine model of oesophageal reconstruction in which ECM scaffolds were used as inductive scaffolds. Evidence of mature nerve, immature nerve and Schwann cells was found within the remodelled ECM at 28 days in the rat body wall model, and at 91 days post surgery in a canine model of oesophageal repair. Additionally, a microscopic and morphological study that investigated the response of primary cultured neurons seeded upon an ECM scaffold showed that neuronal survival and outgrowth were supported by the ECM substrate. Finally, matricryptic peptides resulting from rapid degradation of the ECM scaffold induced migration of terminal Schwann cells in a concentration-dependent fashion in vitro. The findings of this study suggest that the reconstruction of tissues in which innervation is an important functional component is possible with the use of biological scaffolds composed of extracellular matrix. Copyright © 2009 John Wiley & Sons, Ltd. [source] ,3 -Adrenoceptors in urinary bladder,,NEUROUROLOGY AND URODYNAMICS, Issue 6 2007Osamu Yamaguchi Abstract The ,-adrenoceptor (AR) is currently classified into ,1, ,2, and ,3 subtypes. A third subtype, ,3 -AR, was first identified in adipose tissue, but has also been identified in smooth muscle tissue, particularly in the gastrointestinal tract and urinary bladder smooth muscle. There is a predominant expression of ,3 -AR messenger RNA (mRNA) in human bladder, with 97% of total ,-AR mRNA being represented by the ,3 -AR subtype and only 1.5 and 1.4% by the ,1 -AR and , 2 -AR subtypes, respectively. Moreover, the presence of ,1 -, ,2 -, and ,3 -AR mRNAs in the urothelium of human bladder has been identified. The distribution of ,-AR subtypes mediating detrusor muscle relaxation is species dependent, the predominant subtype being the ,3 -AR in humans. Recent studies have suggested that cAMP-dependent routes are not exclusive mechanisms triggering the ,-AR-mediated relaxation of smooth muscle. It has been demonstrated in rats detrusor muscle that cAMP plays a greater role in ,-adrenergic relaxation against basal tone than against KCl-induced tone and that conversely calcium-activated K+ channels (BKca channels) play a greater role under the latter circumstances. In rat models, ,3 -AR agonists increase bladder capacity without influencing bladder contraction and have only weak cardiovascular side effects. Although this evidence points toward the clinical utility of ,3 -AR agonists as therapy for overactive bladder (OAB), pharmacological differences exist between rat and human ,3 -ARs. Development of compounds with high selectivity for the human ,3 -AR, identified by screening techniques using cell lines transfected with the human ,1 -, ,2 -, and ,3 -AR genes, may mitigate against such problems. The association between the tryptophan 64 arginine polymorphism in the ,3 -AR gene and idiopathic OAB is discussed. Neurourol. Urodynam. 26:752,756, 2007. © 2007 Wiley-Liss, Inc. [source] The Effect of Korean Red Ginseng Extract on the Relaxation Response in Isolated Rabbit Vaginal Tissue and Its MechanismTHE JOURNAL OF SEXUAL MEDICINE, Issue 9 2008Sun-Ouck Kim MD ABSTRACT Introduction., Ginseng is an herbal medicine with a variety of biological activities. Aim., The purpose of this study was to investigate the effect of Korean red ginseng (KRG) extract on the relaxation response in isolated rabbit vaginal tissue and its mechanism as a potential therapeutic agent for female sexual dysfunction. Method., Strips of rabbit vagina were mounted in organ chambers to measure isometric tension. After the strips were precontracted with phenylephrine, the contractile responses to KRG extract (1,20 mg/mL), nitric oxide inhibitor (N[omega]-nitro-L-arginine methyl ester [L-NAME]), an inhibitor of soluble guanylate cyclase (methylene blue), an inhibitor of Ca2+ -activated K+ channels (tetraethylammonium [TEA]), and an adenosine triphosphate (ATP)-sensitive K+ channel blocker (glybenclamide) were examined. Main Outcome Measures., The relaxation of the vaginal tissue strip was assessed after treating KRG extract or other chemicals. Results., KRG (1,20 mg/mL) extract relaxed the vaginal tissue strip in a dose-dependent manner up to 85%. The relaxation effect was significantly inhibited by L-NAME (30 µM) and methylene blue (30 µM) (P < 0.05). In addition, KRG inhibited the contraction induced by depolarization with 10, 20, and 40 mM KCl. The KRG-induced relaxation effect was significantly inhibited by TEA (300 µM) (P < 0.05), and not by glybenclamide (30 µM). Conclusions., These data show that KRG extract has a relaxing effect on rabbit vaginal smooth muscle tissue. These effects might be mediated partly through the NO pathway and hyperpolarization via Ca2+ -activated K+ channels. Kim S-O, Kim MK, Lee H-S, Park JK, and Park K. The effect of Korean red ginseng extract on the relaxation response in isolated rabbit vaginal tissue and its mechanism. J Sex Med 2008;5:2079,2084. [source] In vitro effects of lidocaine on the contractility of equine jejunal smooth muscle challenged by ischaemia-reperfusion injuryEQUINE VETERINARY JOURNAL, Issue 1 2010M. GUSCHLBAUER Summary Reasons for performing study: Post operative ileus (POI) in horses is a severe complication after colic surgery. A commonly used prokinetic drug is lidocaine, which has been shown to have stimulatory effects on intestinal motility. The cellular mechanisms through which lidocaine affects smooth muscle activity are not yet known. Objectives: To examine the effects of lidocaine on smooth muscle in vitro and identify mechanisms by which it may affect the contractility of intestinal smooth muscle. Hypothesis: Ischaemia and reperfusion associated with intestinal strangulation can cause smooth muscle injury. Consequently, muscle cell functionality and contractile performance is decreased. Lidocaine can improve basic cell functions and thereby muscle cell contractility especially in ischaemia-reperfusion-challenged smooth muscle. Methods: To examine the effects of lidocaine on smooth muscle function directly, isometric force performance was measured in vitro in noninjured and in vivo ischaemia-reperfusion injured smooth muscle tissues. Dose-dependent response of lidocaine was measured in both samples. To assess membrane permeability as a marker of basic cell function, release of creatine kinase (CK) was measured by in vitro incubations. Results: Lidocaine-stimulated contractility of ischaemia-reperfusion injured smooth muscle was more pronounced than that of noninjured smooth muscle. A 3-phasic dose-dependency was observed with an initial recovery of contractility especially in ischaemia-reperfusion injured smooth muscle followed by a plateau phase where contractility was maintained over a broad concentration range. CK release was decreased by lidocaine. Conclusion: Lidocaine may improve smooth muscle contractility and basic cell function by cellular repair mechanisms which are still unknown. Improving contractility of smooth muscle after ischaemia-reperfusion injury is essential in recovery of propulsive intestinal motility. Potential relevance: Characterisation of the cellular mechanisms of effects of lidocaine, especially on ischaemia-reperfusion injured smooth muscle, may lead to improved treatment strategies for horses with POI. [source] Dynamic association between ,-actinin and ,-integrin regulates contraction of canine tracheal smooth muscleTHE JOURNAL OF PHYSIOLOGY, Issue 3 2006Wenwu Zhang The adhesion junctions of smooth muscle cells may be dynamically regulated during smooth muscle contraction, and this dynamic regulation may be important for the development of active tension. In the present study, the role of ,-actinin during smooth muscle contraction was evaluated in tracheal smooth muscle tissues and freshly dissociated cells. Stimulation with acetylcholine (ACh) increased the localization of ,-actinin at the membrane of freshly dissociated smooth muscle cells, and increased the amount of ,1 integrin that coprecipitated with ,-actinin from muscle tissue homogenates. GFP-,-actinin fusion proteins were expressed in muscle tissues and visualized in live freshly dissociated cells. GFP-,-actinin translocated to the membrane within seconds of stimulation of the cells with ACh. Expression of the integrin-binding rod domain of ,-actinin in smooth muscle tissues depressed active contraction in response to ACh. Expression of the ,-actinin rod domain also inhibited the translocation of endogenous ,-actinin to the membrane, and inhibited the association of endogenous ,-actinin with ,1 -integrin in ,-actinin immunoprecipitates from tissue extracts. However, the expression of ,-actinin rod domain peptides did not inhibit increases in myosin light chain phosphorylation or actin polymerization in response to stimulation with ACh. Results suggest that contractile stimulation of smooth muscle causes the rapid recruitment of ,-actinin to ,-integrin complexes at the membrane, and that the recruitment of ,-actinin to integrin complexes is necessary for active tension development in smooth muscle. [source] Regulation of bladder muscarinic receptor subtypes by experimental pathologiesAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 3 2006M. R. Ruggieri Sr Summary 1 The M3 muscarinic receptor subtype is widely accepted as the receptor on smooth muscle cells that mediates cholinergic contraction of the normal urinary bladder and other smooth muscle tissues, however, we have found that the M2 receptor participates in contraction under certain abnormal conditions. The aim of this study was to determine the effects of various experimental pathologies on the muscarinic receptor subtype mediating urinary bladder contraction. 2 Experimental pathologies resulting in bladder hypertrophy (denervation and outlet obstruction) result in an up-regulation of bladder M2 receptors and a change in the receptor subtype mediating contraction from M3 towards M2. Preventing the denervation-induced bladder hypertrophy by urinary diversion prevents this shift in contractile phenotype indicating that hypertrophy is responsible as opposed to denervation per se. 3 The hypertrophy-induced increase in M2 receptor density and contractile response is accompanied by an increase in the tissue concentrations of mRNA coding for the M2 receptor subtype, however, M3 receptor protein density does not correlate with changes in M3 receptor tissue mRNA concentrations across different experimental pathologies. 4 This shift in contractile phenotype from M3 towards M2 subtype is also observed in aged male Sprague,Dawley rats but not females or either sex of the Fisher344 strain of rats. 5 Four repeated, sequential agonist concentration response curves also cause this shift in contractile phenotype in normal rat bladder strips in vitro, as evidenced by a decrease in the affinity of the M3 selective antagonist p -fluoro-hexahydro-sila-diphenidol (p -F-HHSiD). 6 A similar decrease in the contractile affinity of M3 selective antagonists (darifenacin and p -F-HHSiD) is also observed in bladder specimens from patients with neurogenic bladder as well as certain organ transplant donors. 7 It is concluded that although the M3 receptor subtype predominately mediates contraction under normal circumstances, the M2 receptor subtype can take over a contractile role when the M3 subtype becomes inactivated by, for example, repeated agonist exposures or bladder hypertrophy. This finding has substantial implications for the clinical treatment of abnormal bladder contractions. [source] CAN WE DIFFERENTIATE BETWEEN AIRWAY AND VASCULAR SMOOTH MUSCLE?CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2004Darren J Fernandes SUMMARY 1.,Airway smooth muscle (ASM) has recently been termed the ,frustrated' cell of the lung given that contraction of ASM has no proven useful physiological function in adults and yet is indelibly associated with pathological conditions by virtue of its unwanted airflow-limiting actions in asthma. In contrast, pulmonary vascular smooth muscle contraction plays an essential role in the control of blood flow through the lung. 2.,Little is known of the differences in phenotype between human ASM and pulmonary vascular smooth muscle (VSM) tissues, but differences in contractile protein and transcription factor expression and regulation of contractile protein promoter activity have been documented. Similarly, the embryological signals in mice required for differentiation of ASM versus pulmonary VSM are distinct. 3.,Bronchoconstriction in asthma is currently treated with ,2 -adrenoceptor agonists, which relax contracted ASM cells. An additional approach may be to use gene therapy to render ASM unable to contract (via disruption of their contractile apparatus organization). 4.,Application of ASM-specific gene therapies would rely on minimal actions on other lung smooth muscle tissues, including pulmonary and bronchial vascular smooth muscle. The combination of mRNA analysis of laser-captured microdissected tissue with in situ immunohistochemical staining for protein should be very useful in terms of being able to characterize definitively the differences in mRNA and protein expression between the smooth muscle species of the lung. Any discovery of an ASM-selective target could provide a novel lead for ASM-directed anti-asthma therapy. [source] | |||||||||||||