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Biomedical subjects

M G Matera

Publications and source records attributed to M G Matera.

At least 37 records · Page 2Linked to original sources

Pulmonary disposition of lomefloxacin in patients with acute exacerbation of chronic obstructive pulmonary disease. A multiple-dose study.

In this study we have measured the concentrations of lomefloxacin at steady state in serum and in the intrapulmonary region at specified intervals for 24 h following administration of the last dose of drug in patients suffering from acute exacerbation of chronic obstructive pulmonary disease (COPD). Twenty subjects were enrolled. They received lomefloxacin 400 mg orally once-daily for 5 consecutive days. All patients were divided into five groups, with 4 subjects in each group, according to sampling times (2, 4, 8, 12, and 24 h after the last dose). At bronchoscopy, bronchial biopsies and bronchoalveolar lavage (BAL) were performed. At 12 h after the last dose, serum concentration of lomefloxacin was >1.0 microg/mL and at 24 h it was still detectable, but, at all times, the concentrations in bronchial secretion, bronchial mucosa, and epithelial lining fluid (ELF) were greater than the concentrations in serum [bronchial secretions (pg/mL) = 2.5+/-1.2; 2.2+/-1.0: 2.0+/-1.1; 1.8+/-1.1; 0.6+/-0.3. bronchial mucosa (microg/g) = 5.9+/-2.1; 6.2+/-1.8; 2.6+/-2.2; 1.9+/-1.5; 1.0+/-0.9. ELF (microg/mL) = 6.9+/-2.8; 5.9+/-2.6; 3.1+/-1.9; 2.2+/-1.0; 0.8+/-1.3. serum (microg/mL) = 3.2+/-1.4; 2.8+/-0.9: 2.1+/-1.5; 1.2+/-1.1; 0.4+/-0.81. We must stress that we observed a large inter-individual variability in concentrations. Our data show that lomefloxacin once-daily induces high and sustained concentrations in the various potential sites of pulmonary infection and clearly indicate that the pharmacokinetic behavior of this fluoroquinolone permits once-daily administration in patients with acute exacerbations of COPD.

Administration, Oral↗

Parenteral antibiotic therapy in the treatment of lower respiratory tract infections. Strategies to minimize the development of antibiotic resistance.

Antibiotic use is often imputed for increases in the prevalence of infections due to antibiotic-resistant bacteria. Resistance depends on the variety of genotypes in the large bacterial population and also on the selective pressures that are produced along the antibiotic concentration gradients in the body. In effect, at certain selective concentrations the antibiotic eliminates the susceptible majority, leaving a selected remainder intact. Therefore, the choice of antibiotics for the treatment of lower respiratory tract infections should take into consideration not only their effectiveness but also the pharmacokinetics of each agent and its delivery schedule. In fact, the potential therapeutic efficacy of an antibiotic depends not only on its spectrum of action, but also on the concentration it reaches at the site of infection. Most infections occur in the tissues of the body rather than in the blood and that it is accepted that appropriate antibiotic therapy requires the maintenance of significant concentrations of antibiotics at the site of infection in the lung long enough to eliminate the invading pathogen. Thus, the development of dosing schedules for most antimicrobials has been based on the postulate that drug levels need to be above the minimal inhibitory concentration (MIC) at this site for most or all the dosing interval. The selection of antimicrobial resistance appears to be strongly associated with suboptimal antimicrobial exposure, defined as an AUIC(0-24)/MIC ratio of less than 100O125. Antimicrobial regimens that do not achieve these values cannot prevent the selective pressure that leads to overgrowth of resistant bacterial subpopulations. It has been suggested that resistance can be avoided with attention to dosing, since dosing which provides an AUIC(0-24)/MIC ratio of at least 100 appears to reduce the rate of the development of bacterial resistance. Unfortunately, very different serum or lung concentration profiles can result in the same AUIC(0-24)/MIC. High doses administered sufficiently may often completely prevent any possibility of attaining a selective concentration. Alternatively, an antibiotic which has good bactericidal potency and maintains tissue and/or serum concentrations greater than the MIC or, better, minimal bactericidal concentration (MBC) throughout the dosing interval is equally effective in minimizing the development of antibiotic resistance.

Anti-Bacterial Agents↗

5-HT modifiers as a potential treatment of asthma.

Increased levels of free 5-HT have been shown to be present in the plasma of symptomatic asthmatic patients compared with levels in asymptomatic patients. In addition, free 5-HT has been shown to correlate positively with clinical status and negatively with pulmonary function. These findings suggest that 5-HT might play a role in the pathophysiology of acute asthma. Accordingly, modifiers of the 5-HT transmitter system such as compounds that affect the 5-HT transporter, prejunctional 5-HT receptors or postsynaptic 5-HT receptors might represent a novel treatment of asthma.

Animals↗

Oral bambuterol compared to inhaled salmeterol in patients with partially reversible chronic obstructive pulmonary disease.

OBJECTIVE: There is now good evidence that inhaled salmeterol is an effective agent in chronic obstructive pulmonary disease (COPD),but, at the present time, data on the effects of bambuterol, which is an oral tarbutaline pro-drug, in patients with COPD are scarce. Moreover, no comparative study between bambuterol and salmeterol in patients with chronic obstructive airway disorders has been published. The objective of this research was, consequently, to compare the efficacy and safety of 20 mg oral bambuterol and 50 microg inhaled salmeterol in patients with partially reversible COPD. METHODS: The speed and length of bronchodilation with 20 mg bambuterol and 50 microg inhaled salmeterol were compared in 16 patients with partially reversible COPD. The investigation and designed as a double-blind, double-dummy, cross-over, placebo controlled and randomised study. Lung function (FEV1, FVC) and systemic variables (subjective tremor, heart rate, blood pressure) were monitored prior to the administration of the drug and for 12 h after each agent on 3 non-consecutive days. RESULTS: Inhalation of salmeterol induced a significant (P < 0.05) increase of lung function when compared with placebo. In addition, oral bambuterol elicited good bronchodilation, with its maximum slightly later than for salmeterol. The mean (+/- SE) AUC(0-12h)S for all patients were 3.134 1 +/- 0.553 for salmeterol and 1963 1 +/- 0.573 for bambuterol. Both AUC(0-12h)S were significantly greater than for placebo (P < 0.05), but there was no significant difference (P = 0.077) between the salmeterol and bambuterol AUC(0-12h)S. Bambuterol, but not salmeterol, caused tremor in four patients. Moreover, it induced a higher heart rate when compared with salmeterol at each considered time after the administration of the drug; differences after 9 and 12 h were statistically significant (P < 0.05). CONCLUSION: Both oral bambuterol and inhaled salmeterol resulted in good bronchodilation in patients with stable COPD. However, bambuterol, but not salmeterol, caused tremor in several subjects and elicited a more pronounced tachycardia.

Administration, Inhalation↗

Influence of higher than conventional doses of oxitropium bromide on formoterol-induced bronchodilation in COPD.

We examined the influence of higher than conventional doses of oxitropium bromide on formoterol-induced bronchodilation in patients with partially reversible stable COPD. Twenty outpatients inhaled one or two puffs of formoterol (12 microg puff(-1)), or placebo. Two hours after inhalation, a dose-response curve to inhaled oxitropium bromide (100 microg puff(-1)) or placebo was constructed using one puff, one puff, two puffs and two puffs, for a total cumulative dose of 600 microg oxitropium bromide. Doses were given at 20-min intervals and measurements made 15 min after each dose. On six separate days, all patients received one of the following: (1) formoterol 12 microg + oxitropium bromide 600 microg, (2) formoterol 12 microg + placebo, (3) formoterol 24 microg + oxitropium bromide 600 microg, (4) formoterol 24 microg + placebo, (5) placebo + oxitropium bromide 600 microg, or (6) placebo + placebo. Both formoterol 12 microg and 24 microg induced a good bronchodilation (formoterol 12 microg, 0.19-0.20 l; formoterol 24 microg 0.22-0.24 l). The dose-response curve of oxitropium, but not placebo, showed an evident increase in FEV1, with a further significant increase of respectively 0.087 l and 0.082 l after the formoterol 12 microg and formoterol 24 microg pre-treatment. This study shows that improved pulmonary function in patients with stable COPD may be achieved by adding oxitropium 400-600 microg to formoterol. There is not much difference in bronchodilation between combining oxitropium with formoterol 12 microg or 24 microg. In any case, formoterol 24 microg alone seems sufficient to achieve the same bronchodilation induced by oxitropium 600 microg alone in most patients.

Administration, Inhalation↗

Bioequivalence assessment of two different tablet formulations of diltiazem after single and repeated doses in healthy subjects.

The study was performed on 14 healthy volunteers in order to compare the pharmacokinetics and hence assess the bioequivalence of two different tablet formulations of diltiazem administered orally. The study was carried out after single doses (60 mg) and repeated doses (60 mg three times a day for six days and 60 mg on the seventh day) according to a randomised, cross-over, open design. The pharmacokinetic parameters AUC0-infinity (ng h/ml), Tmax(h) and Cmax (ng/ml) were calculated for the two formulations after a single dose, while AUCt1-t2 (= AUC for a repetitive dose interval or dosing cycle, ng h/ml) and PTF (peak trough fluctuation) were calculated after repeated doses. The bioequivalence assessment was the shortest 90% confidence interval for the ratio (difference) of expected medians in the respective bioequivalence range (0.80-1.20). The results of this study show that, after either a single dose or repeated doses of test or reference formulations of diltiazem, the pharmacokinetics of the two formulations are similar. The ratios of AUC on day 1 (for single-dose treatment) and on day 7 (for repeated-dose treatment), and the corresponding 90% confidence intervals demonstrate bioequivalence between the two formulations of diltiazem within the accepted range of 0.80-1.20 (80-120%).

Adult↗

Effect of hyperbaric oxygen therapy in experimental subcutaneous and pulmonary infections due to Pseudomonas aeruginosa.

About 80% of nosocomial infections are caused by aerobic bacteria. Pseudomonas aeruginosa is a Gram-negative bacterium belonging to the Pseudomonadaceae family; P. aeruginosa is responsible for 6-22% of all hospital infections. The aim of this study was to evaluate the efficacy of hyperbaric oxygen (HBO2) therapy (2 atm abs x 55 min.day-1) alone for 8 days and combined with antibiotic chemotherapy (amikacin 15 mg.kg-1.day-1 for 8 days by intraperitoneal route) in rats infected subcutaneously and via the pulmonary route. In the rats infected by P. aeruginosa, HBO2 induced a reduction in mortality and morbidity with bacteria eradication in blood culture, bronchial aspirate, and skin biopsies when compared to control. These effects were increased by the use of amikacin, an antibiotic used for the treatment of sensitive Gram-negative bacteria.

Amikacin↗

Neuronorm is a potent and water soluble neurokinin A receptor antagonist.

We report here the synthesis and preliminary pharmacological characterization of a novel water soluble Neurokinin A receptor antagonist named Neuronorm. The synthesis was achieved in high yield by a combination of classical peptide synthesis methodologies, in both solution and solid phase. The pharmacological properties as neurokinin A receptor antagonist were assessed in in vitro experiments on rat vas deferens and guinea pig trachea, and were compared to those of MEN10627.

Animals↗

Possible functional modulation by acetylcholine of nitric oxide on guinea pig isolated trachea.

The aim of this study was to evaluate whether acetylcholine induces NO release. We determined the responses on the cholinergic component of the response to electrical field stimulation (EFS) the effects of L-nitro-arginine-methyl-ester (L-NAME; 1 mM), an inhibitor of NO synthase, of L-Arginine (L-ARG; 1 mM), a precursor of NO synthesis, and methoctramine (0.01-0.1-1 microM), an antagonist of M2 receptors, alone or associated with L-NAME. The experiments were performed on guinea pig isolated intact- or denuded-epithelium tracheal rings contracted in a frequency-dependent manner to EFS. At the maximum frequency tested (30 Hz), the contractile response elicited was 60.36 +/- 0.61% of acetylcholine (100 microM) contraction, while the maximal relaxant effect induced by EFS was -28.40 +/- 0.61% in epithelium intact preparations. A pretreatment with L-NAME significantly (P<0.05) increased the contraction (76.08 +/- 1.39%) and reduced the relaxation elicited by EFS. L-NAME effect on both EFS induced responses were statistically (P<0.05) reversed by the association L-NAME + L-ARG. Methoctramine (1 microM) enhanced contractile (P<0.05) (79.20 +/- 2.21%), as well as relaxant responses (-38.73 +/- 0.99%) elicited by EFS in guinea pig epithelium-intact tracheal rings; in a separate series of experiments, performed on guinea pig epithelium-intact rings, L-NAME increased the contractile responses to methoctramine (82.6 +/- 2.31), but reduced the relaxant ones (26.38 +/- 1.29). In contrast, at the maximum frequency tested, it increased only the contractile response, but not modify the relaxant one, in epithelium denuded rings. In conclusion, the present data showed that the release of acetylcholine from postganglionic cholinergic nerves plays an important role on NO formation and this effect may be modulate by epithelium.

Acetylcholine↗

A comparison of bronchodilating effects of salmeterol and oxitropium bromide in stable chronic obstructive pulmonary disease.

Anti-cholinergic agents are generally regarded as the bronchodilator therapy of first choice in the treatment of stable chronic obstructive pulmonary disease (COPD), considering that they may be more effective than in inhaled beta 2-agonist. However, results of the authors' recent studies conflict to some extent with this suggestion because they demonstrate that this is true only for short acting beta 2-agonists but not for long-acting beta 2-agonists. Oxitropium bromide is an anti-cholinergic drug that has been shown to produce a similar degree of bronchodilation to that obtained with ipratropium bromide, but with a longer-lasting effect. In the present study, the time course of inhaled oxitropium bromide bronchodilation in comparison to that of inhaled salmeterol in a group of patients with partially reversible COPD was evaluated. Twelve male patients with moderate to severe COPD participated in the study. The study had a single-bind, cross-over, randomized design. The bronchodilator activity of 50 micrograms salmeterol hydroxynaphthoate, 200 and 400 micrograms oxitropium bromide and placebo, which were all inhaled from a metered-dose inhaler, was investigated on several non-consecutive days. The highest FVC and FEV1, obtained from one or the other of the reproducible curves, were kept for analysis. Measurements were performed at the following times: immediately before inhalation of treatment, and at 15, 30, 60, 120, 180, 240, 300, 360, 480, 600 and 720 min after inhalation of the individual treatment. Salmeterol tended to have a delayed time to peak effect, but had a longer duration of effect than oxitropium. The response to salmeterol exceeded the response to 200 micrograms oxitropium for 12 h, but its responses were significantly (P < 0.05) greater than those to 200 micrograms oxitropium from 10 to 12 h. From 3 to 12 h, salmeterol also surpassed 400 micrograms oxitropium but differences were not significant (P < 0.05). The mean FEV1 area under the curve was significantly (P < 0.05) larger after salmeterol when compared to 200 micrograms oxitropium bromide, but there was no significant difference (P < 0.05) between salmeterol and 400 micrograms oxitropium bromide. No significant changes in pulse rate, blood pressure or electrocardiograms were found among the four groups as compared with placebo group. These findings confirm and extend what has been demonstrated by the authors' previous studies, and show that salmeterol compares conveniently with anti-cholinergic drugs in terms of effects on lung function at clinically recommended doses.

Aged↗

Early reversibility to salbutamol does not always predict bronchodilation after salmeterol in stable chronic obstructive pulmonary disease.

The assessment of reversibility is recognized as being an essential part of the management of airways obstruction, but testing for reversibility of airways obstruction may not be useful for identifying patients with chronic obstructive pulmonary disease (COPD) who are likely to benefit from bronchodilator treatment. We studied 100 patients with stable COPD. Early reversibility of airways obstruction to 200 mg salbutamol and peak bronchodilation to 50 micrograms salmeterol or 200 micrograms salbutamol were evaluated in four different sessions (two for salbutamol and two for salmeterol), using a double-blind, cross-over, randomized study. Fifteen minutes after inhalation of salbutamol, 47 patients presented an increase in FEV1 greater than 15% of baseline, whereas 48 showed an increase of FEV1 of at least 160 ml from basal value and 33 an increase in FEV1 greater than both 15% of baseline and 200 ml. On the contrary, 69 patients presented an increase in FEV1 greater than 15% of baseline, 65 an increase of FEV1 of at least 160 ml from basal value and 60 an increase in FEV1 greater than both 15% of baseline and 200 ml as maximum increase over baseline usually 2-4 h after inhalation of salmeterol. Twenty-seven other subjects defined as irreversible by the lack of acute improvement in FEV1 after salbutamol, showed an increase in FEV1 greater than 15% of baseline, 20 showed an increase of FEV1 of at least 160 ml from basal value, and 18 showed an increase in FEV1 greater than both 15% of baseline and 200 ml; all had the maximum degree of bronchodilation usually 1-2 h after salbutamol administration. These findings clearly demonstrate that many patients suffering from stable COPD show early reversibility to a short-acting beta 2-agonist and patients who do not manifest early reversibility to salbutamol can still benefit from salbutamol or salmeterol. Therefore, treatments with beta 2-agonists must always be tried.

Adrenergic beta-Agonists↗

Effects of formoterol, salmeterol or oxitropium bromide on airway responses to salbutamol in COPD.

We examined whether a pretreatment with formoterol, oxitropium bromide, or salmeterol might modify the dose-response curves to inhaled salbutamol in patients with stable and partially reversible chronic obstructive pulmonary disease (COPD). Sixteen outpatients with partially reversible, stable COPD received 24 microg formoterol, 50 microg salmeterol, 200 microg oxitropium bromide, or placebo on four non-consecutive days. Spirometric testing was performed immediately before inhalation of treatment and after 2 h. A dose-response curve to inhaled salbutamol was then constructed using doses of 100, 100, 200 microg and 400 microg--that is, a total cumulative dose of 800 microg. Dose increments were given at 20 min intervals with measurements being made 15 min after each dose. Formoterol, salmeterol, or oxitropium bromide elicited a significant increase in forced expiratory volume in one second (FEV1) compared with placebo (mean differences (L) = placebo 0.05; formoterol 0.34; salmeterol 0.27; oxitropium bromide 0.23). Dose-dependent increases in FEV1 were seen (mean values (L) before salbutamol and after a cumulative dose of 100, 200, 400, and 800 microg = placebo: 1.06, 1.28, 1.35, 1.39, 1.41; formoterol: 1.33, 1.37, 1.41, 1.44, 1.44; salmeterol: 1.30, 1.33, 1.36, 1.39, 1.42; oxitropium bromide: 1.27, 1.34, 1.37, 1.41, 1.40). Statistical analysis revealed no significant differences in FEV1 and forced vital capacity (FVC) responses to salbutamol after therapy with formoterol, salmeterol, or oxitropium bromide compared with placebo. This study clearly shows that a pretreatment with a conventional dose of formoterol, salmeterol, or oxitropium bromide does not preclude the possibility of inducing a further bronchodilation with salbutamol in patients suffering from partially reversible chronic obstructive pulmonary disease.

Adrenergic beta-Agonists↗

Cardiac effects of formoterol and salmeterol in patients suffering from COPD with preexisting cardiac arrhythmias and hypoxemia.

OBJECTIVE: There are several reports of documented adverse cardiac effects during treatment with beta-agonists. Since one should be aware that this may be a problem in patients with preexisting cardiac disorders, we have conducted a randomized, single-blind, balanced, crossover, placebo-controlled study to assess the cardiac effects of two single doses of formoterol (12 microg and 24 microg) and one single dose of salmeterol (50 microg) in 12 patients suffering from COPD with preexisting cardiac arrhythmias and hypoxemia (PaO2<60 mm Hg). DESIGN: Each patient was evaluated at a screening visit that included spirometry, blood gas analysis, plasma potassium measurement, and 12-lead ECG. In following nonconsecutive days, all patients underwent Holter monitoring 24 h during each of the four treatments. Holter monitoring was started soon before drug administration in the morning. Plasma potassium level was measured before drug inhalation, at 2-h intervals for 6 h, and at 9, 12, and 24 h following administration. None of our patients took rescue medication during the 24-h period. RESULTS: Holter monitoring showed a heart rate higher after formoterol, 24 microg, than after formoterol, 12 microg, and salmeterol, 50 microg, and supraventricular or ventricular premature beats more often after formoterol, 24 microg. Formoterol, 24 microg, significantly reduced plasma potassium level for 9 h when compared with placebo, whereas formoterol, 12 microg, was different after 2 h and salmeterol, 50 microg, from 4 to 6 h. CONCLUSIONS: The results of this study suggest that if a COPD patient is suffering from preexisting cardiac arrhythmias and hypoxemia, long-acting beta-agonists may have adverse effects on the myocardium, although the recommended single dose of salmeterol and formoterol, 12 microg, allows a higher safety margin than formoterol, 24 microg.

Administration, Inhalation↗

Bioavailability of timolol and aceclidine after ocular instillation in the rabbit.

The bioavailability of timolol and aceclidine after the ocular instillation of each drug (timolol 0.5% or aceclidine 2%) or both combined (timolol 0.5% + aceclidine 2%) has been evaluated in rabbits. 15 male albino rabbits were treated by the instillation of timolol and aceclidine alone or combined in the conjunctival sac of the right eye. Timolol concentrations in humor aqueous were assayed at 10 min, 30 min, 1 hr, 2 hr, 4 hr and 6 hr after instillation by high-performance liquid chromatography (HPLC). Aceclidine was assayed by a pharmacodynamic method: pupillary diameter at the following time intervals 0 (basal value), 1 min, 5 min, 30 min, 1 hr, 2 hr, 4 hr, 6 hr after treatment. Our results demonstrated that no differences in timolol and aceclidine bioavailability were found between simple-drug preparations and their combination.

Administration, Topical↗

Evidence for non-adrenergic non-cholinergic contractile responses in bovine and swine trachea.

Non-adrenergic non-cholinergic (NANC) contraction of airway smooth muscle has been observed in some but not all animal species. The aim of this study was to investigate the NANC-contractile responses in bovine and swine trachea. Proximal and distal bovine and swine trachea were cut in strips and placed in 10 ml organ baths equilibrated in Krebs Henseleit (KH) solution and electrically stimulated (10 sec, 60 V, 2 ms, 4, 10 and 30 Hz). Contractile frequency response curves performed in the presence of the muscarinic antagonist, atropine (100 mM), the angiotensin converting enzyme inhibitor, captopril (1 microM) and the neutral endopeptidase inhibitor, thiorphan (1 microM), added 30 min prior to electrical field stimulation (EFS). In some tissues, incubated with atropine thiorphan and captopril, were also evaluated the effects of a pretreatment with capsaicin (10 microM) or a selective NK1 receptor antagonist, SR 14033 (100 nM) added to the baths 30 min prior to EFS. Bovine and swine proximal and distal tracheal preparations contracted in a frequency-dependent manner to EFS (4, 10 and 30 Hz). Some experiments were also performed with substance P (0.1 nM to 1 microM) in absence or in presence of SR 14033 (10 nM or 100 nM). At the maximum frequency tested (30 Hz), the contractile response elicited in bovine proximal and distal preparations was 194.5 +/- 17.1% and 229.7 +/- 24.1%, of ACh (100 microM), respectively. Similarly, the contractile response elicited by EFS (30 Hz) in swine proximal and distal preparations was 187.2 +/- 12.1% and 181.6 +/- 9.2% of ACh (100 microM), respectively. In tissues incubated with atropine, a significant decrease in smooth muscle sensitivity to EFS was observed (P < 0.05). When tissues were pretreated with captopril and thiorphan, a significant increase in the contractile response to EFS (30 Hz) was observed in all tested tissue preparations (bovine, proximal 210.1 +/- 14.4%, distal 264.3 +/- 16.2%; swine, proximal 199.3 +/- 14.9%, distal 206.3 +/- 16.2%, P < 0.05). In the presence of atropine, captopril and thiorphan a significant increase in the contractile response was observed in bovine and swine distal preparations compared with tissues incubated with atropine only (P < 0.05). These effects were antagonized by a pretreatment with a selective NK1 receptor antagonist, SR 14033. A pretreatment with capsaicin statistically (P < 0.05) enhanced EFS-induced contraction in all tested preparations respect to tissues incubated with atropine, thiorphan and captopril. Substance P induced a concentration dependent contraction of bovine and swine isolated tracheal preparations which was antagonized by a pretreatment with a selective NK1 receptor antagonist, SR 14033. No significant difference in the contractile potency (EC50) nor in maximum response (Emax) was observed to exogenously administered substance P between proximal and distal tracheal preparations. These data suggest that NANC contractile responses are present in bovine and swine trachea and are more evident in distal airways.

Animals↗