Role of the ¹³C-methacetin breath test in the assessment of acute liver injury in a rat model.

AIM: To evaluate the role of the (13)C-methacetin breath test ((13)C-MBT) in the assessment of acute liver injury in a rat model. METHODS: Acute liver injury in rats was induced by a single intraperitoneal injection of D-galactosamine (D-GalN). Forty-eight male Sprague-Dawley rats were randomly assigned to a control group (n = 8) and five model groups (each n = 8), and acute liver injury was assessed at different time points (6, 12, 24, 48 and 72 h) after D-GalN injection. The (13)C-MBT, biochemical tests, 15-min retention rate of indocyanine green (ICGR15), and liver biopsy were performed and compared between the control and model groups. Correlations between parameters of the (13)C-MBT (Tmax, MVmax, CUM120 and DOBmax), biochemical tests, ICGR15 and liver necrosis score were also analyzed using Spearman's correlation analysis. RESULTS: Tmax, MVmax, CUM120 and DOBmax, as well as most of the traditional methods, correlated with the liver necrosis score (r = 0.493, P < 0.05; r = -0.731, P < 0.01; r = -0.618, P < 0.01; r = -0.592, P < 0.01, respectively). MVmax, CUM120 and DOBmax rapidly decreased and were lower than those in the controls as early as 6 h after D-GalN injection (3.84 ± 0.84 vs 5.06 ± 0.78, P < 0.01; 3.35 ± 0.72 vs 4.21 ± 1.44, P < 0.05; 52.3 ± 20.58 vs 75.1 ± 9.57, P < 0.05, respectively) and reached the lowest point 24 h after D-GalN injection. MVmax, CUM120 and DOBmax returned to normal levels 72 h after D-GalN injection and preceded most of the traditional methods, including liver biopsy. CONCLUSION: The (13)C-MBT is a sensitive tool for the timely detection of acute liver injury and early prediction of recovery in a rat model. Further clinical studies are warranted to validate its role in patients with acute liver injury.

Changes in contractile activity of the large intestine in rabbits during the poststress period before and after blockade of muscarinic and nicotinic receptors.

The rabbits were exposed twice to stress, fixation to a frame in the supine position, for 60 min. Contractile activity of all portions of the large intestine was shown to increase significantly during the poststress period. These changes were not observed under conditions of blockade of muscarinic and nicotinic receptors. This state can be considered as dyskinesia impairing large intestinal transit of chyme.

[Metocinium iodide application in patients with irritable bowel syndrome].

In this article result of medication methocinium iodide (Methacin) using at patients with irritable bowel syndrome are observed.

Mechanism for the inhibition of contractile activity of the gastric antrum and pylorus in rabbits during psychogenic stress.

Psychogenic stress in rabbits (fixation to a frame) was accompanied by the inhibition of contractile activity of the gastric antrum and pylorus. These changes persisted during blockade of muscarinic receptors, nicotinic receptors, alpha(2)-adrenoceptors, and beta(1)/beta(2) adrenoceptors. A stress-induced decrease in gastric motor activity was mediated by the nonadrenergic noncholinergic mechanism. It resulted from the influence of a hormonal stress factor on the stomach, which was probably realized through nonadrenergic inhibitory neurons of the enteric nervous system.

Blood plasma proteins modulate the broncholytic effects of a muscarinic receptor antagonist.

Blood plasma proteins modulated the effects of muscarinic receptor antagonist methacin. Administration of methacin in combination with albumin or C-reactive protein (but not with IgG) abolished the broncholytic effect of methacin. It was probably associated with allosteric antagonism to M2, cholinergic receptors on non-nervous cells, which increased antibody production and mediator response. The concentration of serotonin in mesenteric lymph nodes was high during shock.

Effects of cholinotropic and cytostatic drugs on the development of Arthus reaction.

Antimuscarinic effects of ipratropium bromide and atropine are associated with prevention of the development of Arthus reaction, while the cytostatic effects of cyclophosphamide and doxorubicin lead to involution of the thymus and spleen, suppression of antibody production, and aggravation of inflammation, which causes edema of the ankle joint (cyclophosphamide treatment). Apoptosis of tumor cell and inhibition of inflammation can be essential for chemotherapy of malignant and autoimmune diseases.

Stability-indicating method for determination of oxyphenonium bromide and its degradation product by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method was developed for determination of oxyphenonium bromide (OX) and its degradation product. The method was based on the HPLC separation of OX from its degradation product, using a cyanopropyl column at ambient temperature with mobile phase of acetonitrile-25 mM potassium dihydrogen phosphate, pH 3.4 (50 + 50, v/v). UV detection at 222 nm was used for quantitation based on peak area. The method was applied to the determination of OX and its degradation product in tablets. The proposed method was also used to investigate the kinetics of the acidic and alkaline degradation of OX at different temperatures, and the apparent pseudo first-order rate constant, half-life, and activation energy were calculated. The pH-rate profile of the degradation of OX in Britton-Robinson buffer solutions within the pH range 2-12 was studied.

[Effects of cholinergic antagonists in stress].

Effects of methacine, hexamethonium and their combinations with neostigmine on activity of B-lymphocytes in various phases of immune response and development of stress ulcers induced in animals were studied. The drugs were found to modulate B-lymphocyte activity for 28 days and longer. By a water-immersion stress model it was shown that methacin is effective not only as m-cholinolytic but also as an immunoprophylactic drug reducing destructive changes in gastric mucosa. Injection of methacin 30 min before stress (block of m-cholinoreceptors) or 14 days before stress (maximal increase of B cell activity) results in 3-4-fold inhibition of ulcerogenesis in gastric mucosa.

Cholinergic modulation of anaphylactic shock: plasma proteins influence.

Cholinergic drugs can modulate anaphylactic shock and change lymphocyte functions. Plasma proteins modulate effects of muscarinic antagonists during anaphylactic shock. The present investigation was carried out to study the antianaphylactic activity of methacine (antagonist at muscarinic receptors) in combination with neostigmine (anticholinesterase drug). However, it is not known whether plasma proteins-albumin, C-reactive protein (CRP) and immunoglobulin G (IgG) - modify the effects of cholinergic drugs like methacine, serotonin (5-HT) level in the lymphoid organs and quantity of antibody-forming cells (AFC) in the spleen of guinea pigs during experimental anaphylactic shock. It was shown that administration of methacine with neostigmine (40 min and 15 min prior to shock induction, accordingly) at the pathochemical stage revokes shock development. By blocking cholinesterase endogenous acetylcholine is increased and methacine blocks muscarinic receptors and therewith unwanted side effects in the airways (bronchoconstriction) and heart (bradycardia). Administration of the combination of methacine with neostigmine at the immunological stage (guinea pig sensitization) does not affect the course of anaphylactic shock. Administration of methacine with IgG at the pathochemical stage of shock significantly decreases shock intensity, while administration of methacine with CRP or albumin has no influence on the shock. Administration of IgG or CRP (not albumin) at the immunological stage of shock and albumin or IgG (not CRP) at the pathochemical stage leads to reduction of the anaphylactic reaction. Application of methacine with neostigmine or IgG (effective combinations of drugs) results in normalization of antibody response in the spleen and 5-HT level in the lymphoid organs. Administration of methacine with CRP or albumin (ineffective combinations of drugs) leads to increase of antibody response in the spleen and 5-HT level in the lymphoid organs. Administration of hexamethonium or aceclidine aggravated anaphylactic shock reaction. Thus, the combination of methacine with neostigmine can regulate the pathochemical stage of shock and the 5-HT release. At the pathochemical stage of shock IgG increases the antianaphylactic activity of methacine, but albumin and CRP abolish it.

In vivo effects of amtolmetin guacyl on lipid peroxidation and antioxidant defence systems. Comparison with non-selective and COX-2 selective NSAIDs.

1. The in vivo effects of the non-steroid anti-inflammatory drug (NSAID) amtolmetin guacyl, a pro-drug of the NSAID tolmetin, on lipid peroxidation, glutathione levels and activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase) in rat gastric mucosa, colon mucosa and liver, were compared with the effects of non-selective (indomethacin, diclofenac) and COX-2 selective (celecoxib) NSAIDs. 2. Indomethacin treatment led to an increase in lipid peroxidation, glutathione peroxidase and glucose-6-phosphate dehydrogenase activities and to a decrease in catalase activity and glutathione levels in gastric mucosa. In contrast, amtolmetin guacyl treatment was without effects in gastric and colon mucosa, or liver from control animals. Like amtolmetin guacyl, celecoxib had no effect on the lipid peroxidation, or on enzyme and non-enzyme antioxidant defence systems in gastric mucosa. 3. It is suggested that the lack of pro-oxidant effects in vivo associated with amtolmetin guacyl treatment contribute improved gastric tolerability.

[Use of sevoflurane during cardiosurgical and endovascular operations in children].

The good tolerability of sevoflurane, the mild and prompt onset of a hypnotic state, the absence of airway irritation, and the safe use of the agent make the anesthetic of choice for introductory anesthesia in pediatric cardiosurgery. The purpose of the study was to develop and assess the procedure of sevoflurane anesthesia during cardiosurgical and endovascular operations in children with congenital heart diseases. Twenty-five children aged 2-9 years (of them 15 children with congenital heart disease) operated on under extracorporeal circulation (EC) were examined. Ten children underwent X-ray surgical endovascular interventions: closure of the patent arterial duct with an "Amplatzer ductus occluder" system. The duration of operations under EC was 116 to 289 min; that of EC was 60-20 (49 +/- 8) min. Endovascular operations lasted 60-80 min. Premedication was made with ketamine, midazolam, and methacin during cardiosurgical operations. The children were referred without premedication, escorted by their parents for endovascular surgical interventions where in the parents' presence the children were given inhalational sevoflurane at a concentration of 5-6% through the mask of an anesthetic apparatus until they fell asleep. This made it possible to avoid the child's weeping and resistance and to puncture the peripheral vein without pain. Steady-state hemodynamics and metabolism suggest that combined anesthesia using sevoflurane at a concentration of 1.3-22% of the minimal alveolar one is adequate in correcting congenital heart disease in children. The application of this anesthetic procedure permitted extubation of 73% of children within 1-2 hours when their condition met the criteria for early activation and extubation.

Masking mechanisms of bitter taste of drugs studied with ion selective electrodes.

The masking mechanisms of the bitter taste of propantheline bromide (PB) and oxyphenonium (OB) bromide by native and modified cyclodextrins, saccharides, surfactants, organic acids, nonionic and anionic polymers, and other compounds were investigated with ion selective electrodes. The intensity of the bitter taste for a mixed solution of cyclodextrin with PB or OB was quantitatively explained from the observed electromotive force with the following assumptions: the complex and the masking agent do not have any tastes and the bitter taste is independent of other tastes. Sodium dodecyl sulfate reduced the bitter taste remarkably, and this reduction was also explicable on the basis of the same mechanism. Sodium taurodeoxycholate enhanced the bitter taste, because of its strong bitterness, although it formed 1 : 1 complexes with PB and OB. The masking mechanism of saccharides was ascribed to overcoming the weak bitterness of the drug by the strong sweetness. Lambda-carrageenan suppressed the bitter taste remarkably. This suppression was ascribed to the binding of PB and OB to lambda-carrageenan, the effect of the solution viscosity on the bitter taste, and the covering of the bitter taste receptor by lambda-carrageenan. It was suggested that the moderate masking by other polymers was attributable to the effect of the solution viscosity or the receptor covering. Native and modified beta-cyclodextrins, sodium dodecyl sulfate, lambda-carrageenan, Tween 20, and sodium carboxymethyl cellulose are good masking agents for the bitter tastes of PB and OB. The drug ion selective electrode is a useful tool for understanding of the masking mechanism of the bitter taste, screening of masking agents, and estimation of appropriate concentrations of the masking agents.

Role of cholinergic structures in individual resistance of rat circulatory system to posthemorrhagic hypoxia.

Experiments employing ultrasound technique showed that nonselective blockade of central muscarinic cholinoceptors with amizyl significantly increases the number and lifespan of rats highly resistant to acute massive blood loss. This pretreatment increased individual resistance of the circulatory system to posthemorrhagic hypoxia (blood pressure and portal blood flow rate). Preliminary blockade of central nicotinic cholinoceptors and peripheral muscarinic cholinoceptors with cyclodol and methacin, respectively, had no effect on the percentage of rats highly and low resistant to acute blood loss. Preliminary blockade of peripheral muscarinic cholinoceptors with methacin prevented the decrease in the cardiac output in low resistant animals during the posthemorrhagic period.

[Mechanisms of inhibition of the contractile activity in the ileo-caecal zone in rabbits under psychogenic stress].

In experiments on unanaesthetized rabbits, myoelectric activity (contractile activity index) of distal ileum, caecum, and proximal colon in two sites was studied under stress induced by fastening a rabbit to the table in supine position. The stress caused sharp decrease (up to complete disappearance) of the contractile activity in all studied compartments of the ileocaecal intestine with partial or complete restoration after release of the animal. Nonselective blockade of pre- and postsynaptic alpha-adrenoceptor with dihydroergotoxin abolished the initial component of the specified inhibitory response. The latter was caused by "adrenergic inhibition" as a result of action of catecholamines circulating in blood on inhibitory smooth muscle alpha-adrenoceptor. Against the background of muscarinic cholinoceptor blockade, the stressor inhibition of ileocaecal contractile activity observed in control experiments was completely preserved. The periods of supression of ileoceacal contractile activity under stress resistant to blockade of alpha-, beta-adrenoceptor and muscarinic cholinoceptor, are caused by the mechanism of "nonadrenergic noncholinergic inhibition", which is realized at the expence of activation of the enteric inhibitory neurones.

Solution structures of 1:1 complexes of oxyphenonium bromide with beta- and gamma-cyclodextrins.

The solution structures of complexes of oxyphenonium bromide (OB) with beta- and gamma-cyclodextrins (beta- and gamma-CDs, respectively) in deuterium oxide have been investigated by 500 MHz proton NMR spectroscopy and molecular mechanics calculations. The chemical shifts induced by complex formation provide the 1:1 binding constants and the chemical shift variations, DeltadeltaOB-CD, with complexation for the protons of OB and the CDs. The observed binding constants are very close to those obtained by other methods and are in the following order: beta-CD > gamma-CD > alpha-CD. Initial structures of the complexes are constructed on the basis of the ROESY spectra and the DeltadeltaOB-CD values and are optimized by molecular mechanics calculations. The intermolecular distances between the protons of OB and CD calculated for these structures are well-correlated with the observed ROESY intensities. The cyclohexyl group of OB penetrates deeply into a beta-CD cavity, and the phenyl group is close to the wide rim of the cavity. The phenyl and cyclohexyl groups of OB are both incorporated into a gamma-CD cavity. Furthermore, these structures of the complexes are consistent with the suppression of bitter taste and basic hydrolysis of OB by CDs and the polarity of binding sites of OB.

Variable effects of previously untested muscarinic receptor antagonists on experimental myopia.

PURPOSE: Atropine, pirenzepine, and himbacine prevent form-deprivation myopia (FDM) when administered intravitreously. The mechanisms and sites of action of these drugs against myopia are not clear. To shed further light on whether this mechanism is muscarinic, several other muscarinic antagonists were tested. METHODS: Various concentrations of atropine, pirenzepine, dexetimide, scopolamine, tropicamide, benztropine, dicyclomine, gallamine, mepenzolate, oxyphenonium, propantheline, procyclidine, 4-diphenylacetoxy-N-methylpiperidine (4-DAMP), hexahydro-sila-difenidol (HHSiD), p-fluorohexahydro-sila-difenidol (pf-HHSiD), methoctramine, AFDX-116, and quinuclidinyl benzilate (QNB) were injected into goggled eyes of Leghorn cockerels three times at 48-hour intervals. Fellow control eyes received saline. Control animals received saline in both eyes. Twenty-four hours after final injections, refraction, eye weight, and axial length were measured, and eyes were prepared for microscopy. RESULTS: Other than atropine and pirenzepine, only oxyphenonium caused full rescue from FDM (goggled versus control; mean +/- SD; refraction differences: -9.50 +/- 0.22 D vs. 0.83 +/- 0.31 D, P < 0.001; wet weight differences: 75.67 +/- 3.84 mg vs. 2.33 +/- 6.14 mg, P < 0.001; axial length differences: 0.80 +/- 0.05 mm vs. 0.03 +/- 0.04 mm, P < 0.001). Oxyphenonium-treated retinas showed no damage. Of the other compounds, several elicited partial rescue and/or damaged the retina, whereas others had no effect. CONCLUSIONS: Oxyphenonium prevents FDM in chicks. The ineffectiveness or partial effectiveness of other compounds, coupled with the high concentrations of effective compounds required to prevent FDM, suggests that muscarinic antagonists act to prevent FDM, either at sites distant from the retina, or through a nonmuscarinic mechanism, on which only some of these drugs act.

[Mechanism of the serotonin effect on motility of the duodenum, ileum, and jejunum in awake rabbits]. / Mekhanizmy vliianiia serotonina na motornuiu aktivnost' dvenadtsatiperstnoi, toshchei i podvzdoshnoi kishki u bodrstvuiushchikh krolikov.

I. v. administration of serotonin to alert rabbits produced a phasic change of contractile activity of duodenum, ileum, and jejunum including excitatory and inhibitory components. It is shown that stimulation of the small bowel motility is caused by serotonin activation of non-cholinergic excitatory mechanism with participation of effector cholinergic neurones. The initial suppression of the motility is caused by participation of nonadrenergic noncholinergic inhibitory mechanism, and the secondary inhibition of contractile activity of a small bowel with serotonin has an adrenergic nature.

[Action of regulators of peripheral cholinergic processes on development of early arrhythmia in myocardial ischemic rats]. / Vliianie reguliatorov perifericheskikh kholinergicheskikh protsessov na razvitie rannikh aritmii u krys pri ishemii miokarda.

Occlusion of the left coronary artery in rats provoked ventricular tachycardia (VT) and ventricular fibrillation (VF) within the first 30 min of ischemia leading to death in 20% animals. Methacin (i.v., 100 micrograms/kg) significantly prolonged VT and VF without effects on the survival. Acetylcholine (i.v., 10 micrograms/kg/min) had no influence on VT frequency and severity but prevented VF. Rats from this group survived. The same effect was observed for neostigmine (i.v., 25 micrograms/kg). Nicotine (i.v., 2.5 micrograms/kg/min) prolonged VT episode duration but did not change frequency and severity of VF and survival. Ganglioblockers hexametony and azametony (i.v., both in a dose 500 micrograms/kg) significantly attenuated VT, prevented VF and death of the animals. Thus, cholinotropic drugs may have both antiarrhythmic and proarrhythmogenic effects in early arrhythmias induced by ischemia.

Stoichiometric and microenvironmental effects on hydrolysis of propantheline and oxyphenonium bromides in cyclodextrin solutions.

The effects of alpha-, beta-, and gamma-cyclodextrins (CDs) on the basic hydrolysis of propantheline bromide (PB) and oxyphenonium bromide (OB) are analyzed in terms of the stoichiometry and microenvironments of their complexes. The rate constant of each species is evaluated with binding constant data for the 1:1, 1:2, and 2:1 complexes. The dielectric constant of the binding site of PB is estimated from the ultraviolet maximum wavelength in reference with the ethanol-water and dioxane-water systems. The energy-optimized structures of some complexes of PB with beta- and gamma-CD are obtained by molecular mechanics. Because the ester linkage of PB in the 1:1 complex with alpha-CD and in the 2:1 complex with gamma-CD is located near hydroxyls of the CD rim, these complexes catalyze the hydrolysis of PB. In contrast, the hydrolysis is inhibited by the formation of the 1:1 and 1:2 complexes of beta-CD and the 1:1 complex of gamma-CD because the ester linkage of PB is rather deeply incorporated into the CD cavities for these complexes. All the CDs inhibit the hydrolysis of OB. The rate constant of the 1:1 complex of OB and CD is in the decreasing order alpha-CD > gamma-CD > beta-CD. This order is consistent with that of the local dielectric constants of the binding sites.

Dual effects of muscarinic M(2) acetylcholine receptors on the synthesis of cyclic AMP in CHO cells: dependence on time, receptor density and receptor agonists.

1. Muscarinic M(2) receptors normally inhibit the production of cyclic AMP via G(i) proteins, but a stimulatory component occurs in their effect at high agonist concentrations, believed to be based on the activation of G(s) proteins. We investigated the conditions which determine the occurrence and extent of the stimulatory component in CHO cells stably expressing muscarinic M(2) receptors. 2. Biphasic concentration-response curves (decline followed by return towards control values) were obtained after 10 min incubation with carbachol, oxotremorine-M, acetylcholine, arecoline and arecaidine propargyl ester, but the upward phase was missing with oxotremorine, methylfurmethide, furmethide and pentylthio-TZTP. Shortening the incubation favoured the occurrence of the stimulatory component. Carbachol (1 mM) and oxotremorine-M (1 mM) brought about net stimulation (above 100% of control) of cyclic AMP synthesis during 2 min incubations. The stimulatory components disappeared after the density of receptors had been lowered with oxyphenonium mustard. 3. All agonists stimulated the synthesis of cyclic AMP in cells pretreated with pertussis toxin. 4. Most differences between agonists regarding the stimulatory component of their effect on cyclic AMP synthesis could be explained by differences in their efficacy and the induced receptor internalization. 5. We propose that the G(s)-mediated stimulatory component of the effect of muscarinic M(2) receptors on cyclic AMP synthesis only occurs if the density of activated receptors is high enough to saturate the G(i) proteins and proportionate to the receptors' low affinity for the G(s) proteins. It tends to be abolished by receptor internalization.