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L E Ziganshina

Publications and source records attributed to L E Ziganshina.

At least 19 recordsLinked to original sources
PubMed2005

Fluoroquinolones for treating tuberculosis.

BACKGROUND: Fluoroquinolones are sometimes used to treat multiple-drug-resistant and drug-sensitive tuberculosis. The effects of fluoroquinolones in tuberculosis regimens need to be assessed. OBJECTIVES: To assess fluoroquinolones as additional or substitute components to antituberculous drug regimens for drug-sensitive and drug-resistant tuberculosis. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group Specialized Register (April 2005), CENTRAL (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to April 2005), EMBASE (1974 to April 2005), LILACS (1982 to April 2005), Science Citation Index (1940 to April 2005), and Russian database (1988 to April 2005). We also scanned reference lists of all identified studies and contacted researchers. SELECTION CRITERIA: Randomized controlled trials of antituberculous regimens containing fluoroquinolones in people diagnosed with bacteriologically positive (sputum smear or culture) pulmonary tuberculosis. DATA COLLECTION AND ANALYSIS: Two authors independently applied inclusion criteria, assessed methodological quality, and extracted data. We used relative risk (RR) for dichotomous data, weighted mean difference (WMD) for continuous data (both with 95% confidence intervals (CI)), and the random-effects model if we detected heterogeneity and appropriate to combine data. MAIN RESULTS: Ten trials (1178 participants) met the inclusion criteria. No statistically significant difference was found in trials substituting ciprofloxacin or ofloxacin for first-line drugs in relation to cure (89 participants, 2 trials), treatment failure (388 participants, 3 trials), or clinical or radiological improvement (216 participants, 2 trials). Substituting ciprofloxacin into first-line regimens in drug-sensitive tuberculosis led to a higher incidence of relapse (RR 7.17, 95% CI 1.33 to 38.58; 384 participants, 3 trials) and longer time to sputum culture conversion (WMD 0.50 months, 95% CI 0.18 to 0.82; 168 participants, 1 trial), although this was confined to HIV-positive participants. Adding or substituting levofloxacin to basic regimens in drug-resistant areas had no effect. A comparison of sparfloxacin versus ofloxacin added to regimens showed no statistically significant difference in cure (184 participants, 2 trials), treatment failure (149 participants, 2 trials), or total number of adverse events (253 participants, 3 trials). AUTHORS' CONCLUSIONS: Only ciprofloxacin, ofloxacin, levofloxacin, and sparfloxacin have been tested in randomized controlled trials for treating tuberculosis. We cannot recommend ciprofloxacin in treating tuberculosis. Trials of newer fluoroquinolones for treating tuberculosis are needed. No difference has been demonstrated between sparfloxacin and ofloxacin in drug-resistant tuberculosis.

Antitubercular Agents↗
PubMed2004

Effects of dimephosphone, xydiphone, and ionol on the content and activities of rat liver cytochromes P-450 during long-term treatment with phenobarbital.

Effects of dimephosphone, xydiphone, and ionol administered in parallel with phenobarbital on the content of cytochromes P-450 in rat liver and on the rate of C-hydroxylation of diazepam, haloperidol, and prednisolone by rat liver microsomal enzymes were studied in vitro. Dimephosphone, xydiphone, and ionol exhibited similar inductive effects on C-hydroxylation reactions in the CYP P-450 system during treatment with phenobarbital. Xydiphone and ionol in a dose of 1 mmol/kg canceled phenobarbital-induced increase in P-450 cytochrome content in rat liver. Sex-dependent cytochromes P-450 are involved in the prednisolone and haloperidol C-hydroxylation reactions in rats.

Animals↗
PubMed2003

Contractile activity of human greater saphenous vein mediated by P2-receptors.

In vitro experiments were carried out to measure the contractile responses to P(2)-receptor agonists in the greater saphenous vein isolated from patients with obliterating vascular atherosclerosis and varicose veins of the legs. In patients with varicose veins, the contractile responses of the greater saphenous vein to ATP, alpha,beta-methylene-ATP, and UTP were significantly lower than in patients with obliterating atherosclerosis, while the responses to ADP, adenosine, and 2-methylthio-ATP were similar in both groups. These data attest to the presence of P(2)-receptor-mediated contraction component in the greater saphenous vein, which are pronouncedly weakened during varicose disease.

Adult↗
PubMed2003

Therapeutic efficiency of dimephosphone and xydiphone in experimental pulse therapy with prednisolone.

Experiments on rats showed that pulse therapy with prednisolone (100 mg/kg intraperitoneally for 3 days) stimulated urinary excretion of hydroxyproline, increased the content of inorganic phosphorus, promoted the increase in the content of dienic conjugates and catalase activity, and decreased serum levels of MDA and ceruloplasmin. Ten-day treatment with dimephosphone (208 mg/kg) or xydiphone (45 mg/kg) after pulse therapy with prednisolone normalized urinary excretion of hydroxyproline and reduced the levels of dienic conjugates. Dimephosphone did not change, while xydiphone normalized the level of MDA decreased by prednisolone.

Administration, Oral↗
PubMed2002

P2 receptors: theoretical background for the use in clinical practice.

Here we review the results of physiological, pharmacological, and pathophysiological studies of ATP receptors, P2 type receptors. Characteristics of two families of P2 receptors (P2X and P2Y) are presented and the possibility of using preparations affecting these receptors is discussed.

Animals↗
PubMed2000

Effect of temperature on guinea pig urinary bladder contraction mediated via P2X-receptors.

In vitro experiments showed that P2X-receptor agonist alpha,beta-methylene-ATP and electrical field stimulation in the presence of muscarinic and alpha-adrenoreceptors blockers induced contractile responses of isolated guinea pig bladder, which were more pronounced at 30 degrees C than at 37 degrees C or 42 degrees C. P2X-receptor antagonist pyridoxal-6-phosphate-2',4'-disulfonic acid, produced a more potent inhibitory effect on contractions induced by electrical field stimulation at 30 degrees C in comparison with that at 37 degrees C or 42 degrees C, while the contractions induced by alpha,beta-methylene-ATP were similarly suppressed at all examined temperatures.

Adenosine Triphosphate↗
PubMed1997

Effects of extracellular pH on agonism and antagonism at a recombinant P2X2 receptor.

1. Under voltage-clamp conditions, the activity of agonists and antagonists at a recombinant P2X2 receptor expressed in Xenopus oocytes was examined at different levels of extracellular pH (pHe). 2. In normal Ringer (Mg2+ ions absent), the amplitude of submaximal inward currents to ATP was increased by progressively lowering pHe (8.0-5.5). ATP-responses reached a maximum at pH 6.5 with a 5 fold increase in ATP-affinity; the apparent pKa was 7.05 +/- 0.05. 3. Receptor affinity for ATP was lowered when extracellular Ca2+ ions were replaced with equimolar Mg2+ ions. However, the amplitude of the ATP-responses was still enhanced under acidic conditions, reaching maximal activity at pH 6.5 with a 5 fold increase in ATP-affinity; the apparent pKa was 7.35 +/- 0.05. 4. ATP species present in the superfusate (for the above ionic conditions and pH levels) were calculated to determine the forms of ATP which activate P2X2 receptors: possible candidates include HATP, CaHATP and MgHATP. However, levels of these protonated species increase below pH 6.5, suggesting that receptor protonation rather than agonist protonation is more important. 5. The potency order for agonists of P2X2 receptors was: ATP> 2-MeS-ATP ATPgammaS> ATPalphaS> >CTP >BzATP, while other nucleotides were inactive. EC50 and nH values for full agonists were determined at pH 7.4 and re-examined at pH 6.5. Extracellular acidification increased the affinity by approximately 5 fold for full agonists (ATP, 2-MeSATP, ATPyS and ATP alpha S), without altering the potency order. 6. The potency order for antagonists at P2X2 receptors was: Reactive blue-2 >trinitrophenol-ATP > or = Palatine fast black > or = Coomassie brilliant blue > or = PPADS>suramin (at pH 7.4). IC50 values and slopes of the inhibition curves were re-examined at different pH levels. Only blockade by suramin was affected significantly by extracellular acidification (IC50 values: 10.4 +/- 2 microM, at pH 7.4; 78 +/- 5 nM, at pH 6.5; 30 +/-6 nM, at pH 5.5). 7 In summary, a lowered pHe enhanced the activity of all agonists at P2X2 receptors but, with the exception of suramin, not antagonists. Since a lowered pHe is also known to enhance agonist activity at P2x receptors on sensory neurones containing P2X2 transcripts, the sensitization by metabolic acidosis of native P2x receptors containing P2X2 subunits may have a significant effect on purinergic cell-to-cell signalling.

Adenosine Triphosphate↗
PubMed1996

Effects of P2-purinoceptor antagonists on degradation of adenine nucleotides by ecto-nucleotidases in folliculated oocytes of Xenopus laevis.

The aim of the present study was to examine the effects of a number of P2-purinoceptor antagonists on degradation of adenine nucleotides by Xenopus laevis oocyte ecto-nucleotidase. Folliculated oocytes readily metabolize all three naturally-occurring nucleotides, the order of preferential substrates being ATP >ADP > AMP. The degradation of ATP and ADP was decreased significantly in the presence of several P2X- and P2Y-purinoceptor antagonists, including suramin, PPADS, Cibacron blue, Coomassie Brilliant blue, Evans blue, Trypan blue, Congo red, and PIT (each compound was used at 100 microM). All these compounds inhibited the degradation of ATP by up to 60%, whereas the hydrolysis of ADP was inhibited by Congo red and PIT by 75-80%. In addition, DIDS (100 microM) and TNP-ATP (100 microM) selectively inhibited the breakdown of ATP, and sodium azide (10 mM) selectively inhibited the breakdown of ADP. The enzymatic breakdown of either ATP or ADP was unaffected by 8-pSPT (100 microM), an antagonist of P1-purinoceptors, or by oxidized ATP (100 microM), an antagonist of P2Z-purinoceptors. The degradation of AMP was prevented completely by PIT (100 microM) and ingibited significantly by Congo red (100 microM). In conclusion, the present study shows that most of currently available antagonists of P2-purinoceptors inhibit the enzymatic breakdown of extracellular ATP and ADP. The inhibitory effect on ecto-nucleotidase activity should be taken into account when these antagonists are used in pharmacological experiments.

Adenine Nucleotides↗
PubMed1996

Acute paw oedema formation induced by ATP: re-evaluation of the mechanisms involved.

ATP-induced inflammation was investigated using subplantar injection in the mouse hind paw. The order of efficacy of purinoceptor agonists for inducing paw oedema (30 nmol per paw) was ATP = alpha, beta-methylene ATP = 2-methylthio ATP > adenosine > UTP > ADP > AMP. Diadenosine polyphosphates effectively induced paw oedema formation with an order of efficacy of: P1,P4-di(adenosine-5')tetraphosphate = P1,P5-di(adenosine-5')-pentaphosphate = P1,P6-di(adenosine-5')hexaphosphate >>ATP = P1,P3-di(adenosine-5')triphosphate > P1,P2-di(adenosine-5')pyrophosphate. Systemic administration of P2-purinoceptor antagonists (30-100 mu mol/kg), suramin, 4,4'-diisothiocyanatostilbene-2,2'-disulphonate, pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid and cibacron blue, reduced the intensity of ATP-induced oedema. At 30 mu mol/kg 8-(p-sulfophenyl)theophylline (non-selective adenosine receptor antagonist), 3,7-dimethyl-1,1-propargylxanthine (adenosine A2 receptor antagonist), triprolidine (histamine H1 receptor antagonist), ranitidine (histamine H2 receptor antagonist) and ketanserin (5-hydroxytryptamine 5-HT2 receptor antagonist), but neither 8-cyclopentyl-1,3-dipropylxanthine (adenosine A1 receptor antagonist), nor indomethacin (cyclooxygenase inhibitor) inhibited the ATP-induced swelling. Topical (100 nmol per paw), but not systemic (100 mu mol/kg) administration of NG-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor) reduced the intensity of the ATP-induced paw oedema. These results show that ATP can induce an inflammatory oedematous reaction and contribute to our understanding of the underlying mechanisms.

Adenosine Triphosphate↗
PubMed1996

Differential degradation of extracellular adenine nucleotides by folliculated oocytes of Xenopus laevis.

The degradation of extracellular ATP and ADP by Xenopus oocytes was studied to investigate whether one or two ecto-enzymes are responsible for breakdown of both nucleotides. At a concentration of 100 microM, the half-life of ATP and ADP was 33 and 40 min, respectively. Degradation of ATP caused an initial fast and then a sustained accumulation of ADP in the buffer, while the concentration of AMP in the buffer increased slowly, but progressively, in a relatively linear manner. The rates of degradation of ATP and ADP were similar at pH levels between 7 and 10, but the velocity of breakdown of ATP was significantly higher than that of ADP at pH of 5-6. In divalent cation-free buffer, the addition of 0.1 mM of Ca2+, but not equimolar Mg2+, significantly potentiated the degradation of ATP by oocytes while, in the case of ADP, each of these divalent cations were able to potentiate its degradation. The rate of hydrolysis of ATP and its kinetic constants were not significantly different in the presence or absence of ADP (50 microM). In conclusion, differences in pH- and cation-dependency, and absence of inhibitory effect of ADP on degradation of ATP suggest that degradation of ATP and ADP by oocytes is provided by separate enzymes, namely Ca2+/Mg(2+)-dependent ecto-ATPase and ecto-ADPase, rather than by one ecto-enzyme.

Adenine Nucleotides↗
PubMed1996

Full sensitivity of P2X2 purinoceptor to ATP revealed by changing extracellular pH.

A full pharmacological characterization was carried out on a recombinant ATP-gated ion channel (P2X2 purinoceptor) expressed in Xenopus oocytes. This slowly-desensitizing neuronal P2X2 purinoceptor, activated by ATP (EC50 = 4.6 +/- 1 microM at pH 7.4; n = 4), showed the agonist potency order: ATP > or = 2-MeSATP = ATP gamma S > or = ATP alpha S > > Bz-ATP. The receptor affinity for ATP was enhanced 5-10 fold by acidifying the bathing solution (to pH 6.5) but was diminished 4-5 fold in an alkaline solution (pH 8.0). The maximum activity of P2X2 purinoceptors and the activity order of a series of nucleotides were unaltered by changing extracellular pH. Interestingly, ATP sensitivity at a recombinant P2Y1 purinoceptor remained unaltered with changing extracellular pH. These results indicate that acidotic conditions in the synaptic cleft could strengthen purinergic transmission at neuronal P2X2 purinoceptors.

Adenosine Triphosphate↗
PubMed1996

A novel P1 purinoceptor activates an outward K+ current in follicular oocytes of Xenopus laevis.

Follicular oocytes of Xenopus laevis possess P1 purinoceptors where, seemingly, both adenosine (Ado) and ATP are agonists. The basis of ATP agonism at this P1 purinoceptor was investigated using electrophysiological and biochemical procedures. Ado and ATP activated an outward K+ current that reversed at -90 mV, was reduced by TEA and was inhibited by theophylline and 8-(p-sulphophenyl)-theophylline but not by suramin. Outward K+ current to ATP and Ado also was inhibited by alpha, beta-methylene ATP. The affinity constants for Ado and ATP were identical, although ATP was a partial agonist. The potency order of nucleosides/nucleotides was 5'-N-ethylcarboxamide- adenosine > Ado > AMP > CGS-21680 > beta, gamma-methylene ATP = ATP > ADP > R-N6 phenylisopropyl-adenosine, whereas 2-methylthioadenosine, ATP-O-(3-thiotriphosphate), uridine 5'-triphosphate and alpha, beta-methylene ATP were inactive. Outward K+ current to ATP and nondegradable Ado analogs was unaffected by adenosine deaminase (although this enzyme prevented Ado agonism), which suggests that ATP is not broken down to Ado before activating K+ channels. The activity of oocyte ecto-ATPase was determined by HPLC analysis of ATP breakdown and by the production of inorganic phosphate. Oocyte ecto-ATPase showed a low rate of ATP hydrolysis and was incapable of generating sufficient Ado/AMP to activate P1 purinoceptors. The results show that a P1 purinoceptor that is not typical of other known Ado receptors (and ATP receptors) is present in the follicle cell layer of Xenopus oocytes and represents a novel purinoceptor subtype where both Ado and ATP are agonists in their own right.

Adenosine↗
PubMed1995

Characteristics of ecto-ATPase of Xenopus oocytes and the inhibitory actions of suramin on ATP breakdown.

Ecto-ATPase activity of Xenopus oocytes was studied by measuring the production of inorganic phosphate (Pi) from the breakdown of extracellular ATP. Enzyme activity involved Ca2+/Mg(2+)-dependent and Ca2+/Mg(2+)-independent dephosphorylation of ATP. Ca2+/Mg(2+)-dependent ecto-ATPase was active over a limited range of 0.01-1.0 mM ATP, while Ca2+/Mg(2+)-independent ATPase activity was active over a range of 0.1-30 mM ATP. Total enzyme activity was insensitive to changes in buffer pH (pH 7.0-9.0), but increased in a relatively linear manner with: (1) time of reaction (0-90 min), (2) number of cells (1-20 oocytes), and (3) temperature (10-37 degrees C). Ecto-ATPase activity was unaffected by ouabain (100 microM), sodium azide (100 microM), and oligomycin (5 micrograms/ml) (as inhibitors of endo-ATPases) and beta-glycerophosphate (10 mM) and p-nitrophenyl phosphate (10 mM) (as inhibitors of non-specific alkaline phosphatase). Total ecto-ATPase activity was reduced significantly in defolliculated oocytes, suggesting that the enzyme was located mainly on the enveloping follicle cell layer. The range order of preferential substrates was: ATP>GTP, ITP, UTP, CTP, TTP, 2-methylthioATP>ADP, 2-methylthioADP, AMP>>alpha, beta-methylene ATP, beta, gamma-methylene ATP, in the presence of divalent ions (where G is guanosine, I is inosine, U is uridine, C is cytidine and T is ribosylthymine). The P2-purinoceptor antagonist suramin [8-(3-benzamido-4-methylbenzamido)napthalene-1,3,5-trisul phonic acid), 100 microM] significantly inhibited total ecto-ATPase activity; this inhibition was competitive for the Ca2+/Mg(2+)-dependent enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗
PubMed1995

Effects of alpha,beta-unsaturated sulphones and phosphonium salts on ecto-ATPase activity and contractile responses mediated via P2 chi-purinoceptors.

1. In the guinea-pig urinary bladder and vas deferens, several alpha,beta-unsaturated sulphones and phosphonium salts that were tested inhibited ecto-ATPase activity. The sulphones were more active in the bladder but the phosphonium salts were more effective in the vas deferens. 2. These compounds either potentiated or inhibited purinergic contractile responses in the guinea-pig urinary bladder and vas deferens. 3. alpha,beta-Unsaturated sulphones and phosphonium salts represent a new promising class of compounds, capable of modulating purinergic neurotransmission.

Adenosine Triphosphatases↗
PubMed1995

Effects of divalent cations and La3+ on contractility and ecto-ATPase activity in the guinea-pig urinary bladder.

1. Several cations (Ba2+, Cd2+, Co2+, Cu2+, Mn2+, Ni2+, Zn2+ and La3+, all as chloride salts, 1-1000 microM) were tested in the guinea-pig urinary bladder for their ability to: (i) modify contractile responses to electrical field stimulation (EFS), ATP, alpha,beta-methylene ATP (alpha,beta-meATP), carbachol (CCh), and KCl; (ii) affect ecto-ATPase activity. 2. Ba2+ (10-1000 microM) concentration-dependently potentiated contractile responses evoked by EFS (4-16 Hz), ATP (100 microM), alpha,beta-meATP (1 microM), CCh (0.5 microM), and KCl (30 mM). Ni2+ at concentrations of 1-100 microM also potentiated contractility of the urinary bladder, but at concentrations tested its effect was not concentration-dependent. Cu2+ at a concentration of 10 microM and Cd2+ at a concentration of 1 microM potentiated responses to all stimuli, except KCl. Ni2+ at a concentration of 1000 microM and Cd2+ at a concentration of 100 microM inhibited contractions evoked by all stimuli, and at a concentration of 1000 microM Cd2+ abolished any contractions. Responses to ATP and alpha,beta-meATP were selectively inhibited by Cu2+, Zn2+ or La3+, each at a concentration of 1 mM. 3. Cu2+, Ni2+, Zn2+ and La3+ (100-1000 microM) concentration-dependently inhibited ecto-ATPase activity in the urinary bladder smooth muscle preparations, while Ba2+ and Mn2+ were without effect, and Cd2+ and Co2+ caused significant inhibition only at a concentration of 1000 microM. 4. There was no correlation between the extent of ecto-ATPase inhibition and the effect on contractile activity of any of the cations. 5. In conclusion, the ability of some divalent cations to inhibit ecto-ATPase activity and to potentiate or inhibit contractile responses in the guinea-pig urinary bladder appear to be independent effects.

Adenosine Triphosphatases↗
PubMed1995

Effects of P2-purinoceptor antagonists on ecto-nucleotidase activity of guinea-pig vas deferens cultured smooth muscle cells.

Ecto-nucleotidase activity was studied on primary cultures of guinea-pig vas deferens smooth muscle cells by measuring the inorganic phosphate (Pi) production using ATP as a substrate. The ecto-nucleotidase was insensitive to ouabain, oligomycin, sodium azide, p-nitrophenyl phosphate and B-glycerophosphate. Enzyme activity was highly dependent on either Ca2+ or Mg2+. Antagonists of P2X-purinoceptors, pyridoxalphosphate-6-azophenyl-2',4'- disulphonic acid, 4'4'-diisothiocyanatostilbene-2'2'- disulphonate, suramin and pyridoxal-5-phosphate, significantly inhibited ecto-nucleotidase activity. In contrast, the P1-purinoceptor antagonists, 8-p-sulphophenyl theophylline and 1,3-dipropyl-8-cyclopentylxanthine, did not affect the enzyme activity. Thus, when P2-purinoceptors are studied by testing agonists and antagonists potencies, the inhibition of ecto-nucleotidase activity by currently available P2-purinoceptor antagonists should be taken into account.

Adenosine Triphosphatases↗
PubMed1994

Effects of cyclopiazonic acid on contractility and ecto-ATPase activity in guinea-pig urinary bladder and vas deferens.

1. Cyclopiazonic acid (CPA), an inhibitor of sarcoplasmic ATPase, was tested on guinea-pig urinary bladder and vas deferens for its ability: (1) to modify contractile responses to electrical field stimulation (EFS), exogenous ATP, alpha,beta-methylene ATP (alpha,beta-MeATP), carbachol, noradrenaline (NA), histamine, and KCl; (2) to affect ecto-ATPase activity; (3) to modify the release of ATP evoked by EFS. 2. In the urinary bladder, CPA (10 microM) potentiated contractile responses to EFS, exogenous ATP (100 microM), alpha,beta-meATP (1 microM), carbachol (0.5 microM), histamine (30 microM) and KCl (30 mM). In the vas deferens, CPA (10 microM) potentiated responses to EFS, ATP, alpha,beta-meATP, NA (100 microM) and KCl. CPA at a concentration of 1 microM had no effect on ATP-induced relaxation of carbachol-precontracted guinea-pig taenia coli, and at a concentration of 10 microM it markedly increased spontaneous contractile activity of taenia. 3. Ecto-ATPase was estimated to have Vmax and Km values of 0.98 nmol Pi 30 min-1 mg-1 wet tissue and 881 microM ATP in the urinary bladder, and 0.75 nmol Pi 30 min-1 mg-1 wet tissue and 914 microM ATP in the vas deferens, respectively. CPA at a concentration of 10 microM significantly inhibited ecto-ATPase activity by 18% in the urinary bladder and by 24% in the vas deferens. 4. In the guinea-pig vas deferens, CPA significantly potentiated ATP release evoked by EFS from 2.2 +/- 0.8 (6) pmol ATP min-1 g-1 wet tissue to 35.2 +/- 4.8 (6) pmol ATP min-1 g-1 wet tissue (P < 0.01). 5. In conclusion, the potentiation of contractile responses of the guinea-pig urinary bladder and vas deferens by CPA has a non-specific character. CPA inhibited ecto-ATPase activity and increased ATP release, but these effects do not appear to contribute to the potentiation of Pu-purinoceptor-mediated responses since the contractile actions of all the agonists studied were potentiated to the same extent.

Adenosine Triphosphatases↗