Biomedical subjects
Publications and source records attributed to P Turco.
Atropine was used to diagnostic purposes in a 58-year-old man who presented with sinus bradycardia. The patient suffered immediate polymorphous ventricular tachycardia which persisted for 3 mins. External synchronized cardioversion established sinus rhythm and the subsequent hospital course was uneventful.
We report a 62-year-old man with a persistent ventricular rhythm originating in a parasystolic focus associated with frequent ventricular couplets with fixed coupling. Both intravenous (IV) procainamide (1 g) and propafenone (70 mg IV) promptly suppressed only the second component of ventricular couplets, suggesting that re-entry rather than enhanced automaticity was the mechanism of ventricular couplets. On the contrary, the nonresponse of ventricular rhythm and ventricular couplets to verapamil (10 mg IV) suggested that triggered activity should not play a role in the genesis of this ventricular rhythm. The mechanisms of the ventricular couplets (rapidly discharging parasystolic focus vs. re-entry) are discussed.
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Theophylline plasma levels and FEV1 were measured in patients affected by chronic obstructive pulmonary disease and a concomitant disease state (congestive heart failure, chronic cor pulmonale, obesity, peptic disease, hepatic cirrhosis, chronic renal failure) and treated with a sustained release theophylline preparation. Our results indicate that, only in patients affected by congestive heart failure and chronic cor pulmonale, is there a decreased plasma clearance of the drug. Low levels of plasma theophylline were measured in obese patients probably because they received an inadequate posology.
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The study was a comparison of the effects on respiratory function produced by four antihypertensive agents with receptor-blocking properties (atenolol, oxprenolol, labetalol, metoprolol), when used in combination with a diuretic (chlorthalidone) in four homogeneous groups of hypertensive patients also suffering from chronic obstructive lung disease. All the agents with the exception of labetalol caused systematic and considerable worsening of functional parameters monitored in the trial. Treatment with labetalol, on the other hand, led to an improvement in respiratory function. Labetalol thus proved to be the most reliable and selective of the drugs tested for administration to patients with severe chronic airflow limitation.
The efficacy of procaterol, a new selective beta 2-stimulant (by pressurized aerosol), and its protection against the effects of non-specific bronchial stimulation (fog test) was evaluated in ten hyperreactive seasonal atopics in an open trial of twelve days duration. Preliminary results had proved that single (10 micrograms) and repetitive (10 micrograms t.i.d.) doses of procaterol induced a strong bronchodilation. Accordingly the pre-medication with procaterol (10 micrograms) completely prevents the flow limitation subsequent to the non-specific bronchial stimulation.
Twelve subjects suffering from type A chronic respiratory insufficiency were admitted to a double blind, randomized, placebo-controlled trial. The aim of the trial was the evaluation of the effects of the oral administration of L-carnitine, 2 g twice daily for 15 days, on the metabolic and respiratory parameters, at the mild physical work load involved in rehabilitative respiratory physiokinesitherapy. As previously reported, treatment with L-carnitine prevents the metabolic acidosis and hyperventilation caused by physiokinesitherapy in patients with chronic respiratory insufficiency. In correlation with the metabolic role of L-carnitine, the results of this trial suggest that L-carnitine is an essential training-like metabolic factor, particularly when the physical performance is impaired by inadequate respiratory function.
Several different parameters of respiratory functions were measured to determine the hyperreactive bronchial responses to the fog-test of 21 atopic asthmatic subjects (prick test and RAST positive for grasses). Measurements were made before and after three and six months of prophylaxis with 1 mg b.i.d. ketotifen, with the period of the trial (April to September) chosen to correspond to the period of maximal allergen exposure. A further 8-patient control group, without prophylactic treatment, underwent the same fog-test and respiratory function measurements were repeated at the same times. In the ketotifen-treated patients almost total protection against the bronchoreactive response to the fog-test was seen after only three months of treatment (in June). The effectiveness of the treatment was maintained to the same extent throughout the rest of the 6-month trial.
The authors have evaluated the interference of the H2-antagonists cimetidine and ranitidine with the elimination kinetics of sustained-release anhydrous theophylline, administered per os at the dose of 300 mg b.i.d. in two randomly selected groups of patients suffering from chronic obstructive lung disease. The plasma theophylline trends (obtained over a 12-hour period) were compared in the two groups in basal conditions (on reaching the theophylline steady state) and after 8 days treatment with cimetidine or ranitidine. In addition, the bronchodilator effect of theophylline was evaluated in these experimental conditions by means of FEV1 measurements. Simultaneous administration of ranitidine produced no changes in theophylline elimination, and the bronchodilator effect of theophylline proved both substantial and systematic in the patients treated with this H2-antagonist. On the other hand, the patients treated with cimetidine showed a marked, systematic increase in theophylline plasma levels, even exceeding the upper limit of its known therapeutic range in 4 cases. Despite this, no evidence of a bronchodilator effect was found in the cimetidine-treated patients, while significant effects attributable to theophylline toxicity were observed in the 4 cases with excessive theophylline plasma levels. The simultaneous administration of cimetidine in patients treated with sustained-release anhydrous theophylline thus proved capable of seriously undermining the strategy of theophylline usage precisely on account of the high degree of bioavailability of theophylline in the sustained-release formulation.
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A study was carried out on the use of theophylline (240 mg by infusion) as a functional diagnostic test in patients showing severe chronic airways obstruction. The preliminary results suggested that the pharmacologic action of theophylline (a bronchodilating and vasoactive drug) helps discriminate the different types of anatomo-functional impairments present during a severe chronic bronchial obstruction. The changes in VA and VA/Qc induced by the drug were evaluated. The presence of a lesion mainly affecting the airways or the parenchyma of the lung might be identified by these changes.
Sixty-five patients, 25 with acute bronchopulmonary respiratory tract diseases and 40 with acute exacerbations of chronic respiratory tract infections, were treated by means of intramuscular injection of an extempore combination of 1 g of cefuroxime and 300 mg of acetylcysteine. Patients were divided into two groups according to the acute or chronic nature of their respiratory tract diseases. Positive clinical results were obtained in 62 of the 65 patients. Of a total of 52 pathogens isolated in pretreatment bacteriological tests on sputum cultures, only three were still detectable after treatment. Tolerance of the treatment was good in all patients, no side-effects of any kind being observed.
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This study tested the hypothesis that cimetidine and ranitidine, the new H2-antagonist, may influence the pharmacokinetics of theophylline administered i.v. at two different doses (3.4 and 6.5 mg/kg body wt.). Twenty hospitalized patients with chronic obstructive lung disease (COLD) and peptic ulcer were administered cimetidine or ranitidine orally for 8 days at the routine doses of 2 X 400 mg/day and 2 X 150 mg/day, respectively. Blood samples were collected over a 10-h period before and after H2-antagonist therapy. Cimetidine significantly reduced theophylline clearance, but increased its half-life and the area under the curve (AUC) (p less than 0.001). Ranitidine, on the contrary, did not show any interaction with these pharmacokinetic parameters. Neither of the H2-blocking agents modified the volume of distribution. Furthermore, the delay in theophylline elimination due to cimetidine was more evident at the higher dose of the xanthic drug; this effect induced remarkable changes in plasma theophylline concentrations. Consequently, pharmacokinetic interaction between cimetidine and theophylline may produce serious clinical problems in the management of patients treated with both drugs concurrently, problems which do not arise with ranitidine.
A multiparametrical method was used in order to evaluate the characteristics of fog-challenge-induced bronchoreactivity. The effects of the bronchial stimulation were measured by means of spirometrical tests; determination of ventilatory resistances using a new method by interruption and rapid analysis of the expiratory gases, CO2 and He, according to the "multiple single breath" method. The protective efficacy of salbutamol and the salbutamol plus beclomethasone dipropionate combination was evaluated. The results obtained indicate that the combination exerts a greater protective effect, probably related to the stabilizing action of beclomethasone on the bronchial mucosa.