Biomedical subjects

G Tatsis

Publications and source records attributed to G Tatsis.

13 recordsLinked to original sources

PubMed1998

Efficacy and tolerance of roxithromycin versus clarithromycin in the treatment of lower respiratory tract infections.

In an open, randomized, parallel group study, the efficacy and tolerance of roxithromycin 300 mg po od was compared with clarithromycin 500 mg po bd in the treatment of 60 patients with lower respiratory tract infections (LRTI). The two groups were well-matched demographically. Fifty patients (25 per group) were clinically evaluable at the end of the study and a satisfactory response was found in 88% of those given roxithromycin and 80% of those given clarithromycin. All had received treatment for a minimum of 3 days. Only one (3.3%) of 30 patients in the roxithromycin group reported adverse events compared with seven (23.3%) of 30 in the clarithromycin group. Thus both roxithromycin and clarithromycin are effective in the treatment of LRTI but roxithromycin is better tolerated (P < 0.05) with the advantage of a once-daily dose.

Adolescent↗

PubMed1997

Radiographic determination of total lung capacity in patients with pneumonectomy.

To determine whether total lung capacity (TLC) can be measured from plain chest radiographs in patients with pneumonectomy, we examined 20 such patients (17 male, 3 female) who had pneumonectomy for lung carcinoma. In 16 patients the right lung was preserved, and in 4 the left. The TLC was measured with the helium dilution method and by planimetry of the anterior and lateral projections of the lung on chest radiographs, summing the anterior and lateral projected areas of the lung to a single value, S. The correlation between S and TLC by helium gas dilution was r = 0.95. Linear fit of TLC to S explained 99.5% of the variance in TLC, with the equation. The side resected did not influence the predictive value (p < 0.001). The interquartile range of the residual error was +/-130 ml, and standard error was 64 ml. Therefore in patients with pneumonectomy, TLC of the preserved lung may be estimated within +/-130 ml by planimetry of the anterior and lateral chest radiographs.

Aged↗

PubMed1990

Alveolar partial pressures of carbon dioxide and oxygen measured by a helium washout technique.

A non-invasive technique was developed for measuring alveolar carbon dioxide and oxygen tension during tidal breathing. This was achieved by solving the Bohr equations for mean alveolar carbon dioxide and oxygen tensions (PACO2, PAO2) from known values of the dead-space:tidal volume ratio measured by helium washout, and from the mixed expired partial pressure of carbon dioxide and oxygen. The derived values of wPACO2 and wPAO2 were compared with PaCO2 obtained from arterial gas analysis and PAO2 calculated from the ideal air equation. Four normal subjects and 58 patients were studied. Calculated and measured PCO2 values agreed closely with a difference in mean values (wPACO2 - PaCO2) of 0.01 kPa; the SD of the differences was 0.7 kPa. The difference in mean values between wPAO2 and PAO2 was 0.02 kPa; the SD of the differences was 0.93 kPa. The method is simple and not time consuming, and requires no special cooperation from the patients. It can be applied in the laboratory or at the bedside to any subject breathing tidally. Physiological deadspace:tidal volume ratio, PAO2 and PACO2, static lung volumes, respiratory exchange ratio, carbon dioxide production, oxygen uptake, tidal volume, and total ventilation can be measured with acceptable accuracy and reproducibility in one test. An arterial blood sample is needed initially to provide an independent measure of PaCO2 and for measurement of the alveolar-arterial PO2 difference. Subsequently, PaCO2 can be estimated from wPACO2 sufficiently well for clinical purposes and PaO2 or SaO2 can be monitored by non-invasive methods.

Adult↗

PubMed1986

Calculation of the VD/VT ratio by the helium washout technique.

In four normal subjects and 51 patients with chronic bronchitis-emphysema, bronchial asthma and pulmonary fibrosis, the VD/VT ratio was measured by a helium washout technique (wVD/VT) and by the conventional Bohr's method using the arterial CO2 tension (VD/VT). In 16 patients the wVD/VT ratio was compared with that calculated from Bohr's equation with the alveolar CO2 tension measured by the rebreathing technique (AVD/VT). It was found that the values for the VD/VT ratio obtained by the helium washout technique were very close to those obtained by the conventional method using the PaCO2 or PACO2 values.

Asthma↗

PubMed1984

Distribution of dead space volume in the human lung.

The first four breaths from a multi-breath nitrogen wash-out have been analysed in 20 normal subjects by differentiation and data smoothing of phase II of the expired concentrations of nitrogen and carbon dioxide. This procedure yields a distribution curve which is skewed to the right, the mode of which represents the usual value of dead space. The minimum and maximum values were found by excluding 2.5% of data points at each end of the distribution. The values of minimum, mode and maximum in men were 67.6, 147 and 300 ml. For women the values were 55.4, 109 and 235 ml. It is suggested that this distribution reflects the asymmetrical nature of the bronchial tree and comparison with anatomical data suggests that anatomy is the principal determinant of the distribution of dead space. The contribution made by the spread of the stationary interface within individual bronchioles is evident but small.

Adult↗

PubMed1982

Total effective time of the forced expirogram in disease: sources of error and a correction factor.

Effective time of the forced expirogram is a sensitive index for the detection of mild airways obstruction. However, there is evidence that this measurement is not superior to maximum flow rates in the lower half of the forced vital capacity or even FEV1 and FEV1% in some patients suffering from obstructive lung disease. Furthermore we noticed that in some patients with a decrease of the forced vital capacity caused by exacerbation of airways obstruction, the effective time was not appreciably changed. We concluded that this apparent disadvantage of the effective time is the result of the different forced vital capacities. To eliminate this error we transformed the forced expirogram to the equivalent curve that the patient would produce, if his forced vital capacity was equal to the predicted mean value for his age, sex, and height. The derived corrected total effective time seems to have increased sensitivity for detection of small changes in expirograms obtained from the same subject or from different subjects.

Asthma↗

PubMed1980

Partial effective times of the forced expiratory spirogram in health and mild airways obstruction.

The partial effective times of the expiratory spirogram were calculated in 80 normal non-smoking subjects aged from 20 to 69 years and in 30 patients aged from 30 to 58 years with chronic bronchitis. Of these patients, 28 had a normal FEV1/FVC ratio, while the other two had a low ratio. Partial effective times were calculated for 10% segments of the expired FVC from total lung capacity (0% FVC) to residual volume (100% FVC) and became progressively longer after 50% of the FVC had been expired in normal subjects. The elongation to the partial effective times was more pronounced with age. In the patients with simple chronic bronchitis (normal FEV1/FVC ratio) the partial effective times were longer than normal after 50% of the FVC had been expired and after 10% of the FVC had been expired in the two patients with chronic bronchitis and low FEV1/FVC ratio. The partial effective times of the forced expiratory spirogram, especially that at the 80--90% part of the FVC, seem to be very sensitive indices for the early detection of mild airways obstruction.

Adult↗

PubMedDate not supplied

A single-blind crossover study of two different slow release theophylline preparations.

In a single-blind crossover study, two slow release theophylline preparations were evaluated in 18 patients with chronic bronchitis or asthma without cardiac, renal or liver disease. After randomization into two groups, patients were treated, in a crossover study design, with 600 mg choline theophyllinate or 300 mg anhydrous theophylline administered orally every 12 h for 7 days. A 2-day washout period separated the two periods of treatment evaluation. Blood samples in which plasma theophylline concentration was to be measured were taken at 7.30 a.m., 2.00 p.m. and 7.30 p.m. during the last 5 days of therapy with each drug. The mean fluctuation in plasma theophylline concentration was less than or equal to 40% in all 18 patients taking choline theophyllinate yet in only 15 (83%) patients administered anhydrous theophylline. Salbutamol inhaler was more frequently required for the relief of bronchospasm when taking anhydrous theophylline than when taking choline theophyllinate (total of 41 vs 25 puffs, respectively, over 7 days). Drug-related adverse reactions occurred in four patients while taking anhydrous theophylline and in one patient while taking choline theophyllinate.

Asthma↗

PubMedDate not supplied

The effect of steroids on theophylline absorption.

The effect of hydrocortisone on plasma theophylline concentrations was evaluated in 20 patients suffering from chronic bronchitis or stable bronchial asthma. Choline theophyllinate (400 mg) was orally administered every 12 h for 8 days and blood samples were taken every 2 h during the day for the measurement of theophylline concentrations. Intravenous bolus injections of 500 or 1000 mg hydrocortisone on day 5 or day 7, respectively, did not significantly alter plasma theophylline concentrations.

Adult↗

PubMedDate not supplied

Treatment of lower respiratory tract infections with amoxycillin/clavulanic acid in adults.

Patients with lower respiratory tract infections [pneumonia (n = 16), bronchiectasis (n = 5) and acute exacerbations of chronic bronchitis (n = 44)] were treated daily with amoxycillin/clavulanic acid given either 1.2 g intravenously three times daily or 625 mg orally three times daily for 7-15 days. Symptoms, signs and sputum volume and colour were monitored daily. Chest X-ray, sputum culture and Gram-stain examinations were also carried out on days 1 and 5, and immediately after the end of the treatment. There was a clinical improvement, as indicated by the incidence of cough, dyspnoea and rales, and by sputum volume and colour in 90.8% of the patients. Microbiological improvement, as indicated by the complete elimination of sputum pathogens and pus cells, was achieved in the same proportion of patients (90.8%). In one patient, an adverse side-effect, diffuse exanthema, was noted. Amoxycillin/clavulanic acid possesses a high clinical and microbiological efficacy for lower respiratory tract infections.

Administration, Oral↗

PubMedDate not supplied

Partial effective time (teffp7): a new spirometric parameter for lung function assessment.

A new spirometric parameter for lung function assessment, the effective time at the 60-70% part of the forced vital capacity of the lung (teffp7), was considered. A total of 79 subjects were studied in two groups, A and B. In group A (5 healthy non-smokers, 22 patients with obstructive lung disease and 22 with pulmonary fibrosis), forced exhalation and the Helium closed-circuit technique were performed. From these tests, a number of lung function parameters were calculated, including teffp7. In group B (30 patients with bronchial asthma), the same tests were carried out before and 15 min after the administration of two puffs of a bronchodiluent, a beta 2-stimulant. From these tests, various lung function measures were again calculated, as well as the change in these parameters after bronchodilatation. The study shows that teffp7 is a more sensitive index than all the other parameters considered for determining airways condition, either in healthy subjects or in those with airways obstruction. In patients with pulmonary fibrosis, the other parameters considered are also less sensitive than teffp7. From the study of the change after bronchodilatation in patients with bronchial asthma, change in teffp7 was greater than in any other parameter. As teffp7 was the more affected parameter, it was also the more sensitive index for diagnosis of airways obstruction. In conclusion, teffp7 is a sensitive index for the diagnosis of airways obstruction or lung restriction, and it is markedly changed after bronchodilatation.

Asthma↗

PubMedDate not supplied

Bioavailability of a new sustained-release anhydrous theophylline product.

The bioavailability of a new sustained-release anhydrous theophylline product (Theophylline Lavipharm) was evaluated and compared with the bioavailability of a well-established product, Theodur. Two groups of 12 healthy non-smokers were given single doses of 200 or 300 mg of each product and two groups of 12 patients with asthma or chronic obstructive lung disease were given doses of 200 or 300 mg of each product every 12 h for 5-day periods. The values of the area under the plasma theophylline concentration against time curve (AUC), the maximum plasma theophylline concentration (Cmax) and the time taken to reach Cmax (Tmax) for the two products did not differ significantly in the healthy groups or in the patients. The minimum and the average plasma theophylline concentrations and the fluctuation index were also calculated for the patients and there were no significant differences between the values for the two products. The new anhydrous theophylline product, Theophylline Lavipharm, appears to show very similar bioavailability to Theodur. No adverse reactions to the new product were reported.

Adult↗

PubMedDate not supplied

Clinical and microbiological evaluation of pefloxacin in lower respiratory tract infections.

Patients with Gram-negative lower respiratory tract infections (acute exacerbation of chronic bronchitis (n = 23), pneumonia (n = 4), and bronchiectasis (n = 5) were treated with pefloxacin, 400 mg twice daily, given either intravenously or orally. Symptoms, signs and sputum volume and colour were monitored daily. Chest X-rays, sputum culture and Gram-stain examinations were carried out on days 1 and 5, and immediately after the end of the treatment. There was a clinical improvement, as indicated by the incidence of cough, dyspnoea and rales, and by sputum volume and colour in 31 patients (97%). Microbiological improvement, as indicated by the complete elimination of sputum pathogens and pus cells, was achieved in 28 of the patients (88%). In one patient, an adverse effect, renal failure, occurred. These results suggest that pefloxacin is both clinically and microbiologically effective for the treatment of Gram-negative lower respiratory tract infections.

Acinetobacter Infections↗