In vitro Evaluation of Ureteral Contractility: A Comparative Assessment of Human, Porcine and Sheep Ureteral Response to Vardenafil

Objectives: Basic science studies of ureteral physiology and pathophysiology are commonly performed on animal ureters due to several limitations associated with human ureteral sampling. In this work we question whether animal ureters are good replicas of human ureteral behavior for pharmacological studies. Materials and Methods: Ureteral rings from human, porcine and ovine ureters underwent the same organ bath protocol. After stimulation with KCl, ureters were subjected to different doses of vardenafil. Basic contractility and ureteral response to vardenafil were analyzed. Results: A different pattern of basic contractility was evidenced between species. Vardenafil administration induced a dose-dependent reduction in KCl-induced amplitude increase in human ureters and a dose-dependent reduction in autonomic contractile rhythm of porcine and ovine ureters. Although animal ureters could predict the relaxant response of human samples to vardenafil, its effect would have been overestimated using only animal models. Conclusions: Human ureteral investigations cannot entirely be replaced by existing animal models since results of the latter will vary significantly according to the tested pharmaceutical agent.

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Towards Safer Treatments for Benign Anorectal Disease: The Pharmacological Manipulation of the Internal Anal Sphincter

Annals of The Royal College of Surgeons of England ◽

10.1308/003588407x205576 ◽

2007 ◽

Vol 89 (6) ◽

pp. 574-579 ◽

Cited By ~ 7

Author(s):

Oliver M Jones

Keyword(s):

Clinical Trials ◽

Animal Models ◽

Anal Fissure ◽

Anal Sphincter ◽

Internal Anal Sphincter ◽

Small Scale ◽

Organ Bath ◽

Vitro Analysis ◽

In Vitro Analysis

INTRODUCTION The internal anal sphincter (IAS) is an important structure that is responsible for the majority of resting tone of the sphincter complex. It has a central role in continence and damage to the muscle has serious implications. Injury is most frequently from obstetric trauma though iatrogenic injury from proctological surgery is also common. This review expands on how developments in understanding of the pharmacology of IAS might identify drug treatments as alternatives for proctological conditions such as anal fissure, avoiding the risk of sphincter injury. It also examines the role of pharmacology in treatment of those patients with established incontinence. RESULTS Much of the basic physiology and pharmacology of the IAS has been established through in vitro analysis, particularly in the superfusion organ bath. Further analysis has been undertaken using animal models such the pig. Clinical trials have established the efficacy of a number of agents for reducing IAS tone including glyceryl trinitrate and botulinum toxin. These drugs are probably safer, but less effective, than surgery for sphincter spasm, as is seen in anal fissure, though surgery alone or in combination with drug treatment may be appropriate for some patients. In vitro analysis and small-scale clinical trials suggest that phenylephrine and methoxamine may have a role in treating patients with incontinence primarily attributable to inadequate IAS function. CONCLUSIONS The pharmacology of IAS has been extensively studied in the laboratory, both in vitro and in animal models. In a short time, this laboratory work has been applied to clinical problems after testing in clinical trials. It is likely, however, that the best drugs and the optimal targets for manipulation have not yet been identified.

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EFFICACY OF AN ACTIVE COMPOUND OF THE HERB, ASHWAGANDHA IN PREVENTION OF STRESS INDUCED HYPERGLYCEMIA

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2018v10i10.28717 ◽

2018 ◽

Vol 10 (10) ◽

pp. 44 ◽

Cited By ~ 1

Author(s):

Sarjan H. N. ◽

Yajurvedi H. N.

Keyword(s):

Phosphoenolpyruvate Carboxykinase ◽

Ethanolic Extract ◽

Dependent Manner ◽

Stress Exposure ◽

In Vitro Experiment ◽

Isolated Compound ◽

Dose Dependent ◽

Different Doses

Objective: To find out whether an isolated compound (IC) from the ethanolic extract of roots of ashwagandha prevents stress-induced hyperglycemia by direct interference with the action of increased concentration of corticosterone on hepatocytes or by preventing hyper-secretion of corticosterone or both.Methods: A group of rats served as controls, and those in another group were subjected to restraint (1 h) and forced swimming exercise (15 min), after a gap of 4 h daily for 4 w. The third group of rats received orally IC (5 mg/kg bw/rat) 1 h prior to exposure to stressors. After the last treatment period, a blood sample was collected and serum was separated for the estimation of corticosterone and glucose. In in vitro experiment, hepatocytes were treated with different concentrations of corticosterone (100, 200, 300, 400 and 500 ng/ml). In another set of experiment, hepatocytes were treated with different doses of IC (1, 10, 100, 1000 and 10 000 μg/ml of medium) along with corticosterone (400ng/ml). The concentration of glucose and activities of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) were determined after the treatment.Results: Stress exposure caused a significant increase in serum concentration of corticosterone and glucose whereas, administration of IC did not result in similar changes. Further, treatment of corticosterone in in vitro significantly increased the activities of PEPCK and G6Pase and concentration of glucose in a dose-dependent manner in hepatocytes. However, treatment with IC did not interfere with the corticosterone-induced an increase in the activities of PEPCK and G6Pase as well as the concentration of glucose in hepatocytes.Conclusion: The in vivo and in vitro results put together reveal that IC does not directly interfere with the action of corticosterone on hepatocytes. However, it prevents stress-induced hyperglycemia by suppressing hyper-secretion of corticosterone.

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Induction of nitric oxide synthase in rat gastric smooth muscle preparations

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1997.273.5.g1101 ◽

1997 ◽

Vol 273 (5) ◽

pp. G1101-G1107 ◽

Cited By ~ 5

Author(s):

Xi-Long Zheng ◽

Keith A. Sharkey ◽

Morley D. Hollenberg

Keyword(s):

Nitric Oxide ◽

Smooth Muscle ◽

Nitric Oxide Synthase ◽

Time Course ◽

Inos Mrna ◽

Organ Bath ◽

Relaxant Response ◽

Oxide Synthase ◽

Inos Induction

The induction in vitro of inducible nitric oxide synthase (iNOS) in intact gastric circular (CM) and longitudinal (LM) smooth muscle preparations was evaluated 1) pharmacologically, by the appearance of 1 mM l-arginine (l-Arg)-induced relaxation in a precontracted tissue; 2) biochemically, according to the appearance of iNOS mRNA using a reverse transcriptase-polymerase chain reaction; and 3) immunohistochemically, using an iNOS-specific antibody. Functionally, iNOS induction affected the contractile properties of the CM but not the LM preparation. The time course of iNOS induction monitored pharmacologically paralleled exactly the appearance of iNOS mRNA. The relaxant response to l-Arg in iNOS-induced CM tissues was blocked by the iNOS inhibitor aminoguanidine and by the guanylyl cyclase inhibitor LY-83583. The addition of oxyhemoglobin to the organ bath also attenuated the relaxant response, but tetrodotoxin had no effect. The transcriptional inhibitor actinomycin D completely blocked iNOS induction as assessed by both pharmacological and biochemical criteria. In iNOS-induced preparations the iNOS immunoreactivity was not detected in the smooth muscle elements but was localized in a layer of macrophage-related cells that were in apposition to the CM smooth muscle elements. We conclude that the spontaneous induction of iNOS in rat gastric tissue can affect the pharmacomechanical reactivity of the CM elements and that this regulation of the CM contractility is due to the induction of iNOS in a set of macrophage-related cells that are closely apposed to the CM elements so that they selectively affect only the contractility of the CM preparation.

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Cordycepin (3′-deoxyadenosine) pentostatin (deoxycoformycin) combination treatment of mice experimentally infected withTrypanosoma evansi

Parasitology ◽

10.1017/s0031182012001990 ◽

2013 ◽

Vol 140 (5) ◽

pp. 663-671 ◽

Cited By ~ 11

Author(s):

LUCIANA DALLA ROSA ◽

ALEKSANDRO S. DA SILVA ◽

LUCAS T. GRESSLER ◽

CAMILA B. OLIVEIRA ◽

MARIA G. C. DAMBRÓS ◽

...

Keyword(s):

Liver Enzymes ◽

Trypanosoma Evansi ◽

Curative Effect ◽

Therapeutic Protocol ◽

Liver And Kidney ◽

Effect Of Treatment ◽

Dose Dependent ◽

Different Doses

SUMMARYThe aim of this study was to evaluate the anti-trypanosomal effect of treatment with 3′-deoxyadenosine (cordycepin) combined with deoxycoformycin (pentostatin: inhibitor of the enzyme adenosine deaminase)in vitroby using mice experimentally infected withTrypanosoma evansi. In vitro, a dose-dependent trypanocidal effect of cordycepin was observed against the parasite. In thein vivotrials, the two drugs were used individually and in combination of different doses. The drugs when used individually had no curative effect on infected mice. However, the combination of cordycepin (2 mg kg−1) and pentostatin (2 mg kg−1) was 100% effective in theT. evansi-infected groups. There was an increase in levels of some biochemical parameters, especially on liver enzymes, which were accompanied by histological lesions in the liver and kidneys. Based on these results we conclude that treatment using the combination of 3′-deoxyadenosine with deoxycoformycin has a curative effect on mice infected withT. evansi. However, the therapeutic protocol tested led to liver and kidney damage, manifested by hepatotoxicity and nephrotoxicity.

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Effects of gentamicin on spontaneous and agonist-induced in vitro contractions of isolated myometrial tissue from pregnant cows

Medycyna Weterynaryjna ◽

10.21521/mw.6333 ◽

2019 ◽

Vol 75 (11) ◽

pp. 6333-2019

Author(s):

MURAT YUKSEL ◽

HALIS OCAL ◽

AHMET AYAR

Keyword(s):

Contractile Activity ◽

Isometric Force ◽

Displacement Transducer ◽

Organ Bath ◽

Dependent Manner ◽

Gentamicin Sulphate ◽

Spontaneous Contractions ◽

Dose Dependent

The aim of the present study is to examine the effects of gentamicin sulphate on spontaneous, oxytocin and PGF2α induced in vitro contractions of myometrium isolated from pregnant cows. Myometrial strips were obtained from healthy pregnant cows and suspended in a covered organ bath filled with Krebs’ solution at 37°C (pH 7.4) continuously bubbled with 95% oxygen and 5% carbon dioxide: isometric contractions were recorded using an isometric force displacement transducer. After the stabilization of spontaneous contractile activity during a 90-minute equilibration period, contractions were recorded for 20 minutes (control). Gentamicin sulphate was then added to the tissue bath cumulatively and the responses were recorded every 20-minutes for each consecutive dose of gentamicin. In agonist-induced contractions, oxytocin or PGF2α was added to the tissue bath at the end of the equilibration period and the same protocol was followed to investigate the effects gentamicin on these agonist-induced contractions. Gentamicin decreased the frequency and inhibited the amplitude of the spontaneous contractions in a dose dependent manner (p < 0.05). The mean frequency and amplitude of oxytocin-induced contractions was significantly inhibited by the application of gentamicin (p < 0.05). Gentamicin also inhibited the contractions induced by PGF2α in a dose dependent manner (p < 0.05). This study showed gentamicin inhibited, depending on the dosage, oxytocin and PGF2α induced contractions of myometrium isolated from pregnant cows. Upon clinically examining the findings obtained by the study, gentamicin can be used as an antibacterial in septic abort and chorioamniotis in order to prevent premature birth, abortion and early uterus contractions. Further studies are necessary to test whether the same effect will take place in vivo and to examine the effects of longterm use of gentamicin on offsprings.

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VIP and PHM and their role in nonadrenergic inhibitory responses in isolated human airways

Journal of Applied Physiology ◽

10.1152/jappl.1986.61.4.1322 ◽

1986 ◽

Vol 61 (4) ◽

pp. 1322-1328 ◽

Cited By ~ 116

Author(s):

J. B. Palmer ◽

F. M. Cuss ◽

P. J. Barnes

Keyword(s):

Time Course ◽

Electrical Field Stimulation ◽

Inhibitory Response ◽

Organ Bath ◽

Antagonist Activity ◽

Agonist And Antagonist ◽

Human Airways ◽

Dose Dependent ◽

Human Bronchi

There is increasing evidence in many species that vasoactive intestinal peptide (VIP) may be a neurotransmitter in nonadrenergic inhibitory nerves. We have studied the effect of electrical field stimulation (EFS), exogenous VIP, and isoproterenol (Iso) on human airways in vitro. We have also studied a related peptide, peptide histidine methionine (PHM), which coexists with VIP in human airway nerves, and in separate experiments studied fragments of the VIP amino acid sequence (VIP1–10 and VIP16–28) for agonist and antagonist activity. Human airways were obtained at thoracotomy and studied in an organ bath. In bronchi EFS gave an inhibitory response that was unaltered by 10(-6) M propranolol but was blocked by tetrodotoxin, whereas in bronchioles there was little or no nonadrenergic inhibitory response. VIP, PHM, and Iso all caused dose-dependent relaxation of bronchi, VIP and PHM being approximately 50-fold more potent than Iso. VIP, but not Iso, mimicked the time course of nonadrenergic inhibitory nerve stimulation. In contrast bronchioles relaxed to Iso but not to VIP or PHM. Neither propranolol nor indomethacin altered the relaxant effects of VIP or PHM, suggesting a direct effect of these peptides on airway smooth muscle. Neither of the VIP fragments showed either agonist or antagonist activity. We conclude that VIP and PHM are more potent bronchodilators of human bronchi than Iso and that the association between the relaxant effects of these peptides and nonadrenergic inhibitory responses suggests that they may be possible neurotransmitters of nonadrenergic inhibitory nerves in human airways.

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Dose-Dependent Activity of Pyrazinamide in Animal Models of Intracellular and Extracellular Tuberculosis Infections

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01524-10 ◽

2011 ◽

Vol 55 (4) ◽

pp. 1527-1532 ◽

Cited By ~ 42

Author(s):

Zahoor Ahmad ◽

Mostafa M. Fraig ◽

Gregory P. Bisson ◽

Eric L. Nuermberger ◽

Jacques H. Grosset ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Animal Models ◽

Guinea Pigs ◽

Equivalent Dose ◽

Pharmacokinetic Data ◽

Bacterial Counts ◽

Dependent Activity ◽

Dose Dependent ◽

Higher Doses

ABSTRACTRecentin vitropharmacokinetic data suggest that the currently recommended dose of pyrazinamide may be suboptimal for killing intracellular bacilli in humans. We evaluated a range of pyrazinamide doses against intracellular and extracellularMycobacterium tuberculosisin chronically infected mice and guinea pigs, respectively. Antibiotics were given five times weekly for 4 weeks beginning 28 days after infection. Human-equivalent doses of isoniazid reduced lung bacterial counts 10-fold in each species. Pyrazinamide given at 1/4 and 1/2 the human-equivalent dose was minimally active, while human-equivalent doses reduced lung bacterial counts by ∼1.0 log10in each species. Doubling the human-equivalent dose of pyrazinamide reduced the lung bacillary burden by 1.7 and 3.0 log10in mice and guinea pigs, respectively. As in humans and mice, pyrazinamide showed significant synergy with rifampin in guinea pigs. Clinical studies are warranted to investigate the sterilizing activity and tolerability of higher doses of pyrazinamide in combination tuberculosis regimens.

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Genotoxicity and cytotoxicity of sevoflurane in two human cell lines in vitro with ionizing radiation

Colombia Medica ◽

10.25100/cm.v45i3.1327 ◽

2014 ◽

pp. 104-109

Author(s):

Miguel Alcaraz ◽

Samuel Quesada ◽

David Armero ◽

Rocio Martín-Gil ◽

Amparo Olivares ◽

...

Keyword(s):

Micronucleus Test ◽

Human Lymphocytes ◽

In Vitro Toxicity ◽

X Rays ◽

Normal Prostate ◽

Cytotoxic Effects ◽

Prostate Cells ◽

Dose Dependent ◽

Different Doses

Objective: To determine the in vitro toxicity of different concentrations of sevoflurane in cells exposed to X-ray. Methods: The genotoxic effects of sevofluorane were studied by means of the micronucleus test in cytokinesis-blocked cells of irradiated human lymphocytes. Subsequently, its cytotoxic effects on PNT2 (normal prostate) cells was determined using the cell viability test (MTT) and compared with those induced by different doses of X-rays. Results: A dose- and time-dependent cytotoxic effect of sevofluorane on PNT2 cells was determined (p> 0.001) and a dose-dependent genotoxic effect of sevofluorane was established (p> 0.001). Hovewer, at volumes lower than 30 μL of sevofluorane at 100%, a non-toxic effect on PNT2 cells was shown. Conclusion: Sevofluorane demonstrates a genotoxic capacity as determined in vitro by micronucleus test in cytokinesis-blocked cells of irradiated human lymphocytes.

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The effect of indomethacin on the stimulation of protein synthesis by insulin in young post-absorptive rats

Biochemical Journal ◽

10.1042/bj2270255 ◽

1985 ◽

Vol 227 (1) ◽

pp. 255-261 ◽

Cited By ~ 28

Author(s):

P J Reeds ◽

S M Hay ◽

R T Glennie ◽

W S Mackie ◽

P J Garlick

Keyword(s):

Protein Synthesis ◽

Plasma Glucose ◽

Acid Metabolism ◽

Arachidonic Acid Metabolism ◽

Plantaris Muscle ◽

Dose Dependent Decrease ◽

Dose Dependent ◽

Different Doses ◽

Stimulation Of

Groups of young rats (100 g body wt.) were starved from 23:00 to 11:00 h. The animals were then infused intravenously with diluent or insulin at three different doses to achieve plasma insulin concentrations of 20, 50 and 150 microunits/ml. Before the start of the infusion, animals received a single intravenous injection of indomethacin (250 micrograms) or diluent. After 20 min of infusion, the rats were injected with a large amount of labelled phenylalanine and were killed 10 min later. Insulin produced a dose-dependent decrease in plasma glucose and a dose-dependent rise in protein synthesis in cardiac, gastrocnemius, plantaris and soleus muscles. Protein synthesis in the liver was unaffected by insulin. Indomethacin had no effect on plasma glucose concentrations, but blocked the insulin-induced rise in protein synthesis in cardiac, gastrocnemius and plantaris, but not in soleus muscle. The hormone also increased the plasma concentration of prostaglandin E2 and of prostaglandins F2 alpha and E2 in gastrocnemius and plantaris muscle. The results show close similarities to previous observations with isolated rabbit muscles in vitro and suggest that the involvement of arachidonic acid metabolism in the action of insulin on protein synthesis is of physiological significance.

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Prostaglandins alter methacholine-induced secretion in ferret in vitro trachea

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1990.258.2.l75 ◽

1990 ◽

Vol 258 (2) ◽

pp. L75-L80 ◽

Cited By ~ 2

Author(s):

M. E. Deffebach ◽

H. Islami ◽

A. Price ◽

S. E. Webber ◽

J. G. Widdicombe

Keyword(s):

Bovine Serum Albumin ◽

Bovine Serum ◽

Specific Marker ◽

Albumin Concentration ◽

Organ Bath ◽

Cell Secretion ◽

Serous Cell ◽

Dose Dependent ◽

Tracheal Secretion

The ferret trachea was mounted in an organ bath containing Krebs-Henseleit solution with additional bovine serum albumin (BSA). Tracheal secretions were collected and analyzed for albumin, and lysozyme, a specific marker of serous cell secretion. The total secretion volume and output and concentrations of albumin and lysozyme were calculated. Secretion was stimulated with methacholine (20 microM) (Mch), and the effects of the prostaglandins PGD2, PGE1, and PGF2 alpha on methacholine-induced secretion were studied. All responses were dose dependent. PGF2 alpha at 10(-5) M increased the volume of Mch-stimulated secretion twofold, the lysozyme output sixfold, and concentration over threefold, while decreasing the albumin transport by one-half. PGD2 at 10(-5) M reduced Mch-induced secretion volume to 75% control, increased albumin transport to 135%, without affecting lysozyme secretion. PGE1 at 10(-5) M increased Mch-stimulated albumin transport and concentration over twofold, decreased lysozyme release to less than one-third of control, and had no effect on secretion volume. PGE1 caused the albumin concentration to exceed that of the outer bath, indicating active transport. We conclude that prostaglandins selectively alter tracheal secretion induced by cholinergic stimuli.

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