Taenia Coli Research Articles

ChemInform Abstract: Synthesis of Some 1,4-Dihydropyridine Derivatives and Their Calcium Antagonistic Activity.

Seven new 2,6-dimethyl-3,5-diacetyl-4-aryl-1,4-dihydropyridine derivatives have been prepared. Their structures have been elucidated by UV, IR, 1 H-NMR and elementary analysis. The calcium antagonistic activity of these compounds were tested in K + -depolarized taenia coli precontracted with 1 mmol/l Ca 2+

Complex actions of neurotensin in ascending and sigmoid colonic muscle: Involvement of enteric mediators

The brain-gut peptide neurotensin has complex effects on gastrointestinal smooth muscle. Our objective was to elucidate the mechanisms underlying neurotensin contractions in human colon. Discrete concentration response curves to neurotensin were obtained in strips of circular muscle and taenia coli from “normal” ascending and sigmoid colon segments, in the presence and absence of various pharmacological inhibitors. Potency of neurotensin in all regions was similar (pD2 ~7). Atropine and the selective muscarinic receptor antagonists, methoctramine and darifenacin, had no effect on neurotensin contractions. In ascending colon circular muscle, responses were enhanced by indomethacin (indicating inhibitory prostaglandin mechanisms) and by tetrodotoxin (TTX), hexamethonium and L-NAME, suggesting nicotinic and enteric inhibitory neurotransmission, with involvement of nitric oxide. In sigmoid circular muscle, neurotensin responses were also enhanced by TTX and hexamethonium, but were attenuated in the presence of mepyramine, MEN10627 and CP99994, suggesting inhibitory neuronal mechanisms and involvement of histamine and tachykinins, respectively; L-NAME and the GABAB receptor antagonist, CGP36742, were without effect. The transcripts of NTS1 and NTS3 receptors, but not NTS2 receptors, were detected in sigmoid colon circular muscle and taenia coli. No age and gender differences in NTS1 mRNA expression were found. In conclusion, neurotensin contracts circular muscle strips from ascending and sigmoid regions of the human colon via direct (muscle) and indirect (neuronal/non-neuronal mechanisms). The enteric mediators influenced by neurotensin are regionally specific. In taenia coli strips from both ascending and sigmoid colon, neurotensin contractions were unchanged in the presence of inhibitors, suggesting direct actions only.

Kinase-related protein/telokin inhibits Ca2+-independent contraction in Triton-skinned guinea pig taenia coli

KRP (kinase-related protein), also known as telokin, has been proposed to inhibit smooth muscle contractility by inhibiting the phosphorylation of the rMLC (regulatory myosin light chain) by the Ca2+-activated MLCK (myosin light chain kinase). Using the phosphatase inhibitor microcystin, we show in the present study that KRP also inhibits Ca2+-independent rMLC phosphorylation and smooth muscle contraction mediated by novel Ca2+-independent rMLC kinases. Incubating KRP-depleted Triton-skinned taenia coli with microcystin at pCa>8 induced a slow contraction reaching 90% of maximal force (Fmax) at pCa 4.5 after approximately 25 min. Loading the fibres with KRP significantly slowed down the force development, i.e. the time to reach 50% of Fmax was increased from 8 min to 35 min. KRP similarly inhibited rMLC phosphorylation of HMM (heavy meromyosin) in vitro by MLCK or by the constitutively active MLCK fragment (61K-MLCK) lacking the myosin-docking KRP domain. A C-terminally truncated KRP defective in myosin binding inhibited neither force nor HMM phosphorylation. Phosphorylated KRP inhibited the rMLC phosphorylation of HMM in vitro and Ca2+-insensitive contractions in fibres similar to unphosphorylated KRP, whereby the phosphorylation state of KRP was not altered in the fibres. We conclude that (i) KRP inhibits not only MLCK-induced contractions, but also those elicited by Ca2+-independent rMLC kinases; (ii) phosphorylation of KRP does not modulate this effect; (iii) binding of KRP to myosin is essential for this inhibition; and (iv) KRP inhibition of rMLC phosphorylation is most probably due to the shielding of the phosphorylation site on the rMLC.

MRP transporters as membrane machinery in the bradykinin-inducible export of ATP

Adenosine triphosphate (ATP) plays the role of an autocrine/paracrine signal molecule in a variety of cells. So far, however, the membrane machinery in the export of intracellular ATP remains poorly understood. Activation of B2-receptor with bradykinin-induced massive release of ATP from cultured taenia coli smooth muscle cells. The evoked release of ATP was unaffected by gap junction hemichannel blockers, such as 18alpha-glycyrrhetinic acid and Gap 26. Furthermore, the cystic fibrosis transmembrane regulator (CFTR) coupled Cl(-) channel blockers, CFTR(inh)172, 5-nitro-2-(3-phenylpropylamino)-benzoic acid, Gd3(+) and glibenclamide, failed to suppress the export of ATP by bradykinin. On the other, the evoked release of ATP was greatly reduced by multidrug resistance protein (MRP) transporter inhibitors, MK-571, indomethacin, and benzbromarone. From western blotting analysis, blots of MRP 1 protein only, but not MRP 2 and MRP 3 protein, appeared at 190 kD. However, the MRP 1 protein expression was not enhanced after loading with 1 muM bradykinin for 5 min. Likewise, niflumic acid and fulfenamic acid, Ca2(+)-activated Cl(-) channel blockers, largely abated the evoked release of ATP. The possibility that the MRP transporter system couples with Ca2(+)-activated Cl(-) channel activities is discussed here. These findings suggest that MRP transporters, probably MRP 1, unlike CFTR-Cl(-) channels and gap junction hemichannels, may contribute as membrane machinery to the export of ATP induced by G-protein-coupled receptor stimulation.

Colonic fold detection from computed tomographic colonography images using diffusion-FCM and level sets

Colon cancer is the second major cause of cancer related deaths in industrial nations. Computed tomographic colonography (CTC) has emerged in the last decade as a new less invasive colon diagnostic alternative to the usually practiced optical colonoscopy. The overall goal is to increase the effectiveness of virtual endoscopic navigation of the existing computer-aided detection (CAD) system. The colonic/haustral folds serve as important landmarks for various associated tasks in the virtual endoscopic navigation like prone–supine registration, colonic polyp detection and tenia coli extraction. In this paper, we present two different techniques, first in isolation and then in synergism, for the detection of haustral folds. Our input is volumetric computed tomographic colonography (CTC) images. The first method, which uses a combination of heat diffusion and fuzzy c-means algorithm (FCM), has a tendency of over-segmentation. The second method, which employs level sets, suffers from under-segmentation. A synergistic combination, where the output of the first is used as an input for the second, is shown to improve the segmentation quality. Experimental results are presented on digital colon phantoms as well as real patient scans. The combined method has a total erroneous (over-segmentation plus under-segmentation) detection of (6.5 ± 2)% of the total number of folds per colon as compared to (12.5 ± 5)% for the diffusion-FCM-based method and (11.5 ± 3)% for the level set-based method. The p-values obtained from the associated ANOVA tests indicate that the performance improvements are statistically significant.

Multidrug Resistance Protein Transporter and Ins(1,4,5)P3-Sensitive Ca2+-Signaling Involved in Adenosine Triphosphate Export via Gq Protein–Coupled NK2-Receptor Stimulation With Neurokinin A

The purpose of this study is to identify the membrane transport machinery and cell signaling involved in the neurokinin A–inducible release of adenosine triphosphate (ATP) as an autocrine/paracrine signal from cultured guinea-pig taenia coli (T. coli) smooth muscle cells (SMCs). ATP release evoked by neurokinin A was inhibited by L-659877, a NK2-receptor antagonist; by modulators for Ins(1,4,5)P3-sensitive Ca2+-signaling, U-73122, thapsigargin, and 2-APB; and by W-7, a calmodulin inhibitor, and staurosporine, a protein kinase C (PKC) inhibitor, but not by wortmannin, a phosphoinositide 3-kinase inhibitor. The evoked release was suppressed by a multidrug resistance protein (MRP)-transporter inhibitors, MK-571, indomethacin, and benzbromarone, but not by CFTR-inh 172, a CFTR-Cl− channel blocker, and α-glycyrrhetinic acid, a gap junction hemichannel blocker. Neurokinin A caused a marked accumulation of Ins(1,4,5)P3 and an increase in [Ca2+]i in the cultured cells. These findings suggest that stimulation of Gq/11 protein– coupled NK2 receptor with neurokinin A caused a substantial release of ATP from cultured T. coli SMCs and that the evoked release may be mediated by Ins(1,4,5)P3-sensitive Ca2+-signaling, further by PKC and Ca2+/calmodulin signals, and finally by an activation of MRP transporters as the membrane device.

Investigation Into the Mechanism of Anti-Asthmatic Action of Moringa oleifera

ABSTRACT.We have studied the possible mechanism of the antiasthmatic action of Moringa oleifera seed kernel ethanolic extract (EXMO, 400 mg/kg). EXMO produced an increase in the Preconvulsion Dyspnea time induced by histamine and acetylcholine aerosol, a significant reduction in the elevated eosinophil and monocyte counts in the Broncho-Alveolar Lavage fluid of sensitized guinea pigs, reduction in the paw edema volume as compared to the control rats, and decrease in the elevated histamine release from the sensitized guinea pig lungs. The pD2 values of histamine in tracheal chain and taenia coli were significantly greater and that in lung strip was lower in the sensitized animals and treatment with EXMO significantly decreased pD2 values in all three preparations. Our data suggest inhibition of the immediate hypersensitive reaction, histamine release, and the infiltration of various inflammatory cells as possible antiasthmatic mechanisms of action.

The intracellular action of Mn2+ in the Mn2+-induced contraction in the guinea-pig taenia coli

The intracellular action of Mn2+ in the Mn2+-induced contraction in the guinea-pig taenia coli

A constitutive model for smooth muscle including active tone and passive viscoelastic behaviour

A new constitutive model for the biomechanical behaviour of smooth muscle tissue is proposed. The active muscle contraction is accomplished by the relative sliding between actin and myosin filaments, comprising contractile units in the smooth muscle cells. The model includes a chemical part, governing the cross-bridge (myosin head) cycling, that is responsible for the filament sliding. The number of activated cross-bridges govern the contractile force generated and also the contraction speed. A strain-energy function is used to describe the mechanical behaviour of the smooth muscle tissue. Besides the active contractile apparatus, the mechanical model also incorporates a passive viscoelastic part. The constitutive model was calibrated with respect to experiments on smooth muscle tissue from swine carotid artery and guinea pig taenia coli, in terms of isometric and isotonic tensile test results. The model was fully able to reproduce the experimental results.

Up‐regulation of RGS2 Mediate IL‐1beta‐Induced Decrease in Muscle Contraction in Response to NPR‐C activation in Tenia Coli

The proinflammatory cytokine, interleukine‐1β (IL‐1β), plays an important role in inflammation‐induced changes in smooth muscle contraction. IL‐1β inhibits acetylcholine release and muscle contraction in response to Gq‐coupled m3 receptor activation. Our previous studies have shown that the single‐transmembrane natriuretic peptide receptor, NPR‐C is coupled to Gi to stimulation of phosphoinositide (PI) hydrolysis via Gβγ i and muscle contraction.AIMTo characterize the effect of IL‐1β on contraction in response to NPR‐C activation.METHODSRabbit tenia coli were cultured in DMEM‐10 in the presence or absence of IL‐1β for 48 h. Muscle cells isolated from these strips were used for measurement of NPR‐C binding, PLC‐β3 and RGS2 expression, and cANP‐induced PI hydrolysis and muscle contraction.RESULTSPre‐incubation with IL‐1β had no effect on NPR‐C binding or PLC‐β3 expression, but significantly inhibited cANP‐induced PI hydrolysis and muscle contraction. IL‐1β caused a 3‐4 fold‐increase in RGS2, a GTPase‐activating protein that accelerates inactivation of Gαi‐GTP, implying that the decrease in PI hydrolysis and contraction were mediated by increased deactivation of Gαi and formation of Gαβ γtrimer.CONCLUSIONInhibition of cANP‐induced contraction by IL‐1β reflects inhibition of PI hydrolysis resulting from up‐regulation of RGS2 and rapid inactivation of Gαi and inhibition of Gβγ i‐mediated PI hydrolysis.

A Study into External Rectal Anatomy

This study was designed to determine the distance from the anal verge to the anterior peritoneal reflection in vivo, thereby improving the selection of patients for preoperative radiotherapy. Measurement of the distance from the anal verge to the anterior peritoneal reflection, confluence of the taenia, and the origin of the sigmoid mesentery in 50 patients in the lithotomy position. The mean distance from the anal verge to the anterior peritoneal reflection was 11.9 cm (men) and 10 cm (women). To the origin of the sigmoid mesentery, the measurements were 18.8 cm (men) and 19.1 cm (women) and to the confluence of the taenia coli, 20.3 cm (men) and 18.8 cm (women). The distance from the anal verge to the origin of the sigmoid mesentery was approximately 19 cm in both men and women. Below this level tumors have limited mobility and should be amenable to radiotherapy.

Purinergic cotransmission

Adenosine 5'-triphosphate (ATP) is a cotransmitter with classical transmitters in most nerves in the peripheral and central nervous systems, although the proportions vary between tissues and species and in different developmental and pathophysiological circumstances. There was early evidence that ATP was released together with acetylcholine (ACh) from motor nerves supplying skeletal muscle, although it was considered at the time as a molecule involved in the vesicular uptake and storage of ACh. Later it was shown that in the developing neuromuscular junction, released ATP acted on P2X receptor ion channels as a genuine cotransmitter with ACh. Adenosine triphosphate was shown to be released from sympathetic nerves supplying the guinea-pig taenia coli in 1971. Soon after, the possibility was raised that ATP was coreleased with noradrenaline from sympathetic nerves to guinea-pig seminal vesicle, cat nictitating membrane and guinea-pig vas deferens. Sympathetic purinergic cotransmission has also been demonstrated in many blood vessels. Parasympathetic nerves supplying the urinary bladder use ACh and ATP as cotransmitters; ATP acts through P2X ionotropic receptors, whereas the slower component of the response is mediated by the metabotropic muscarinic receptor. Adenosine triphosphate and glutamate appear to be cotransmitters in primary afferent sensory neurons. Adenosine triphosphate, calcitonin gene-related peptide and substance P coexist in some sensory-motor nerves. A subpopulation of intramural enteric nerves provides non-adrenergic, non-cholinergic inhibitory innervation of gut smooth muscle. Three cotransmitters are involved, namely ATP, nitric oxide and vasoactive intestinal polypeptide. In recent years, studies have shown that ATP is released with ACh, noradrenaline, glutamate, gamma-aminobutyric acid, 5-hyroxytryptamine and dopamine in different subpopulations of neurons in the central nervous system.

Spasmogenic effect of the aqueous extract of <i>Tamarindus indica</i> l. (caesalpiniaceae) on the contractile activity of guinea-pig <i>Taenia coli</i>

The effect of aqueous extract of Tamarindus indica (AETI) was studied on the guinea pig taenia coli, due to its use for treatment of constipation in traditional medicines. AETI, at concentrations ranging from 10(-8) mg/ml to 10(-2) mg/ml, increased the spontaneous contractile activity of guinea pig taenia coli in a dose-dependent manner (EC50 = 4x10(-6) mg/ml). This activity was unaffected by atropine. In high K(+), Ca(2+)-free solution containing EDTA, AETI as well as acetylcholine, used as a control, induced tonic contraction. These results suggest that the plant extract exert a spasmogenic effect that would not involve cholinergic mechanism of action. However, these active principles could mobilize both extra cellular calcium and intracellular calcium from internal stores.

Protocol for the Examination of Specimens From Patients With Primary Carcinomas of the Colon and Rectum

The College of American Pathologists offers these protocols to assist pathologists in providing clinically useful and relevant information when reporting results of surgical specimen examinations. The College regards the reporting elements in the “Surgical Pathology Cancer Case Summary (Checklist)” portion of the protocols as essential elements of the pathology report. However, the manner in which these elements are reported is at the discretion of each specific pathologist, taking into account clinician preferences, institutional policies, and individual practice. The College developed these protocols as an educational tool to assist pathologists in the useful reporting of relevant information. It did not issue the protocols for use in litigation, reimbursement, or other contexts. Nevertheless, the College recognizes that the protocols might be used by hospitals, attorneys, payers, and others. Indeed, effective January 1, 2004, the Commission on Cancer of the American College of Surgeons mandated the use of the checklist elements of the protocols as part of its Cancer Program Standards for Approved Cancer Programs. Therefore, it becomes even more important for pathologists to familiarize themselves with these documents. At the same time, the College cautions that use of the protocols other than for their intended educational purpose may involve additional considerations that are beyond the scope of this document.

Cupric ions at high concentrations induce rigor-like contraction in a Ca2+-free medium in the guinea pig taenia coli

Cupric ions at high concentrations induce rigor-like contraction in a Ca2+-free medium in the guinea pig taenia coli

The sources of Ca2+ and the intracellular action involved in cupric ions-induced contraction in the guinea pig taenia coli

The sources of Ca2+ and the intracellular action involved in cupric ions-induced contraction in the guinea pig taenia coli

Effects of Tetrapleura Tetraptera (Taub) Fruit Extract On Some Isolated Tissues: Possible Mechanism(S) of Antihypertensive Action

Hypotensive activities of the alcoholic extract of T. tetraptera fruits have been earlier demonstrated in cats, rats and rabbits. In the present study, we demonstrate myorelaxant actions of the extract in isolated smooth muscle preparations. Relaxations were dose-dependent: EC50s were 0.3 ± 0.01, 2.4 ± 0.1 and 4.3 ± 0.01 mg/ml for rat anococcygeus, rat uterus and guinea-pig taenia coli respectively. Also, spasmogenic actions of noradrenaline, carbachol, Ca2+ and K+ in the rat anococcygeus and uterus were all suppressed by the extract. The effect of the extract on Ca2+-induced contractions were investigated in guinea-pig isolated taenia coli and atria preparations and compared to nifedipine, a calcium- channel blocker . Pre-treatment with T. tetraptera (1-10 mg/ml) and nifedipine (0.01-0.1 μg/ml) for 15 minutes in Ca2+-free K+ (100 mM) medium caused a right ward shift of the concentrationresponse curves for CaCl2-induced contractions in atria and taenia coli with depressed maximal response, suggestive of a non-competitive interaction. In all tissues investigated, the extract nonspecifically reduced both the natural tone and agonist-induced contractions. Thus smooth muscle relaxant actions of the extract may partly account for the hypotensive actions of T. tetraptera fruits. Journal of Science and Technology Vol. 28 (1) 2008 pp. 23-35

A Single Luminally Continuous Sarcoplasmic Reticulum with Apparently Separate Ca2+ Stores in Smooth Muscle

Whether or not the sarcoplasmic reticulum (SR) is a continuous, interconnected network surrounding a single lumen or comprises multiple, separate Ca2+ pools was investigated in voltage-clamped single smooth muscle cells using local photolysis of caged compounds and Ca2+ imaging. The entire SR could be depleted or refilled from one small site via either inositol 1,4,5-trisphosphate receptors (IP3R) or ryanodine receptors (RyR) suggesting the SR is luminally continuous and that Ca2+ may diffuse freely throughout. Notwithstanding, regulation of the opening of RyR and IP3R, by the [Ca2+] within the SR, may create several apparent SR elements with various receptor arrangements. IP3R and RyR may appear to exist entirely on a single store, and there may seem to be additional SR elements that express either only RyR or only IP3R. The various SR receptor arrangements and apparently separate Ca2+ storage elements exist in a single luminally continuous SR entity.

Intra-operative Measurement of Surgical Lengths of the Rectum and the Peritoneal Reflection in Korean

The lengths of the surgical rectum and peritoneal reflection were important factors in treatment modality of rectal tumor. To evaluate the surgical length of rectum, we measured the length of the peritoneal reflections, sacral promontory and termination of the taenia coli from the anal verge by rigid sigmoidoscope in 23 male and 23 females during operation. The mean lengths of the sacral promontory were 16.5± 2.2 cm and 16.1±2.2 cm in the males and females, respectively. As for the peritoneal reflection, the results were anterior (8.8±2.2 cm, 8.1±1.7 cm), lateral (10.8±2.7 cm, 11.4±1.9 cm) and posterior (13.8±2.5 cm, 14.0±1.9 cm), respectively. There were no statistically significant differences between male and female. And only height had a correlation with the length of sacral promontory both in male and female (p=0.015 and p=0.018, respectively). For all the estimated lengths, the length of the sacral promontory had a correlation with the lengths of the anterior (p<0.001 and p=0.001) and posterior (p<0.001 and p<0.001) peritoneal reflections in males and females, respectively. We suggest that the intra-operative lengths of the rectum and peritoneal reflection will be useful information for treatment modality of rectal tumor clinically in Korean.

Alteration of phosphocreatine level of guinea-pig taenia coli upon exposure to imidazole buffer

Alteration of phosphocreatine level of guinea-pig taenia coli upon exposure to imidazole buffer