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Biomedical subjects

S Kelemen

Publications and source records attributed to S Kelemen.

17 recordsLinked to original sources
PubMed1998

A comparison of the availability of tobramycin for inhalation from vented vs unvented nebulizers.

STUDY OBJECTIVE: To compare drug output from a vented nebulizer (Pari LC Jet Plus) with a traditional unvented nebulizer (Hudson 1730 T Up-Draft 11) using aerosolized tobramycin, which is frequently used in the treatment of cystic fibrosis. DESIGN: Six nebulizers of each type were filled with a 4 mL tobramycin (80 mg) solution and were driven by a compressor (Pulmo-Aide). Various inspiratory flows (VI) (0, 5, 10, 15, 20 L/min for the Pari LC Jet Plus and 0, 5, and 10 L/min for the Hudson 1730, all at 40% relative humidity) were directed through each nebulizer. Drug output was measured from changes in weight and concentration (assessed by changes in osmometry) within the nebulizer. Particle size distributions were determined by laser diffraction allowing the calculation of the amount of aerosol output in the respirable range (<5 microm). The nebulizers were first run until end-nebulization to establish total drug output and then for either 4 or 5 min to determine the rate of drug output (mg/min) before intermittent aerosol output. RESULTS: The total drug output without VI for both the unvented and the vented nebulizers was not significantly different, 55 (51, 60) mg for the Hudson 1730 vs 51 (49, 53) mg for the Pari LC Jet Plus (mean [95% confidence limits]). Inspiratory flow had no effect on the unvented Hudson 1730 nebulizer but significantly increased the rate of total drug output and the rate of drug output in the respirable range for the vented Pari LC Jet Plus nebulizer (VI=0, 3.35 [2.84, 3.85] and 1.72 [1.48, 1.96] compared with VI=20, 9.87 [9.03, 10.70] and 6.11 [5.33, 6.88] mg/min). CONCLUSIONS: These findings indicate that the increase in the rate of drug output with VI for the vented nebulizer would result in shorter nebulization times and a relative decrease in drug loss during the expiratory phase.

Anti-Bacterial Agents↗
PubMed1997

A comparison of pulmonary availability between Ventolin (albuterol) nebules and Ventolin (albuterol) Respirator Solution.

The two most common albuterol preparations used for nebulization are: (1) Ventolin (albuterol) respirator solution (Glaxo Canada Inc; Montreal, Canada) of which 2.5 mg (0.5 mL) is diluted with 2 mL of normal saline solution, and (2) the preservative-free, prediluted Ventolin (albuterol) Nebules PF (Glaxo) (2.5 mg/2.5 mL). The two preparations were compared using both a Hudson 1720 "T" up-draft Neb-U-Mist jet nebulizer and a Hudson 1730 "T" up-draft Neb-U-Mist II jet nebulizer (Hudson; Temecula, Calif), which were driven by a compressor (Pulmo-Aide; Devilbiss; Somerset, Pa) and by dry compressed air at 6 and 8 L/min. Particle size distribution was measured with a particle sizer (Malvern 2600; Malvern Instruments; Malvern, UK) and drug output for the nebulizer was calculated from the differences in predrug and postdrug volume and concentration. Drug availability was defined as the amount of drug carried in particles less than 5 microns in diameter. Drug availability was greater with the albuterol respiratory solution, due to the surface activity of the preservative benzalkonium chloride, for both nebulizers but particularly for the 1720. Differences in drug availability between nebulizers exceeded fourfold depending on the preparation, the nebulizer, and the nebulizing flow. These differences could not have been predicted from the manufacturer's specifications. The results suggest that prediction of drug availability must be based on measurements with the specific preparation and the specific nebulizer used.

Aerosols↗
PubMed1997

The choice of jet nebulizer, nebulizing flow, and addition of albuterol affects the output of tobramycin aerosols.

The use of inhaled antibiotics in the treatment of cystic fibrosis has become widespread despite controversy in the literature as to the appropriate dosing regimen and its effectiveness. This study compared two tobramycin (T) preparations (one with and one without the addition of albuterol) using two different jet nebulizers in order to determine if drug output would be affected. Using calibrated flows from a dry compressed gas source of 6 and 8 L/min as well as a specific compressor (Pulmo-Aide), the Hudson 1720 nebulizer was compared with the newer disposable Hudson 1730. The albuterol preparation used in this study was the Ventolin (albuterol) Respirator Solution (VRS). The nebulizers were charged with (1) 2 mL T (80 mg/2 mL) with 0.5 mL VRS (5 mg/mL) and normal saline solution to make the total nebulizer charge of 3 or 4 mL, or (2) 2 mL T and either 1 or 2 mL normal saline solution. A laser diffraction analyzer (Malvern 2600) was used to determine the aerosol particle size distribution. From the distribution, the respirable fraction, which is the fraction of aerosol that could enter and remain in the lungs, was calculated. For all solutions and each particular flow, the Hudson 1730 had a larger respirable fraction of T. The addition of VRS lowered the surface tension of the solution in the nebulizer and resulted in a greater output of T. This effect was most apparent for the 3-mL volume fills of the Hudson 1720. The greatest differences were between the 3-mL nebulizer charges of T using the Hudson 1720 driven by a flow of 6 L/min, which produced 8 mg of T in the respirable fraction, compared with 35 mg produced by the Hudson 1730 driven by a flow of 8 L/min. These results suggest that different nebulizers, different nebulizer solutions, and different techniques of nebulization may result in very different amounts of T aerosol output in the respirable fraction.

Administration, Inhalation↗
PubMed1989

[Hemodynamic effects of verapamil in pulmonary hypertension caused by heart valve disease].

The authors have investigated the haemodynamic effects of verapamil on the pulmonary circulation by 24 patients suffering from secondary pulmonary hypertension, caused by mitral and/or aortic valve diseases. For this purpose the numeric and graphometric analysis of intracavitary right ventricle pressure curve and pulmonary artery pressure tracing was applied. It was observed a selective antihypertensive effect on the lesser circulation. The pulmonary and systemic systolic tension decreased comparing in percentage 3:1, in case of diastolic tension this comparison was 2:1. The decrease in pulmonary circulation was strongly significant. The diminishing of heart rate and the improving of right heart function was not significant. The elevation of end-diastolic pressure of the right ventricle, just as the shape-analysis of pressure curves suggested right ventricle overload.

Adult↗
PubMed1987

Tussiphonographic analysis of cough sound recordings performed by Schmidt-Voigt and Hirschberg and Szende.

The cough sound records published by Schmidt-Voigt and Hirschberg and Szende were submitted to tussiphonographic analysis. It has been established that all the recordings of various types of cough sounds registered in airway disease were of pathological character in the tussiphonographic recordings. It has repeatedly been confirmed that tussiphonography is a suitable means for screening of respiratory diseases.

Cough↗
PubMedDate not supplied

Reactivity of HeLa tumoral cells under the in vitro action of some aromatic compounds from the phytomass.

The in vitro action of some natural polyphenolic preparations, extracted from the leaves of Asclepias syriaca, upon the proteinosynthesis of HeLa cancerous cells and, implicitly, upon the development of HeLa cells cultures was investigated. The significant perturbation of proteic biogenesis, the inhibition of HeLa tumoral cells cultures development, as well as the existence of a dose--response relationship argue the behaviour of these products as in vitro active cytostatic agents. This characterization justifies their introduction in the in vivo screening program on rats bearing of different experimental tumoral lines, for the preclinical pharmacological evaluation of the POLYAS I and POLYAS II vegetable polyphenols antineoplastic activity.

Antineoplastic Agents↗
PubMedDate not supplied

Preclinical qualitative evaluation of the antitumoral pharmacodynamic action of some natural polyphenolic biopreparations.

We have investigated the impact of POLYAS I and POLYAS II polyphenolic biopreparations - specifically separated and purified from Asclepias syriaca leaves, and characterized in vitro as cytotoxic and/or cytostatic agents - on the tumor generation process. A series of in vivo tests of their effect on the development of Guerin T-8 lymphotropic epithelioma and Walker 256 carcinosarcoma were conducted. In a first stage of preclinical trial we had used several tests meant to evaluate their antitumoural activity indices. The same tests were then used under similar experimental conditions in the solid tumoral systems mentioned. A comparative analysis of the antitumoral activity evaluation indices resulting from our tests with the reference indices set by the American and German preclinical screening programs pointed to their compatibility. Thus, we found similar values of mean tumoral regressions, of the ratio between mean tumoral weights of the treated and control groups, respectively, of the T/C products resulting from successive re-tests. Also T/C values resulting from retests were within the limits of admissible variability range. All those results highlighted the antineoplastic pharmacotherapeutic effect of the polyphenolic biopreparations and also proved that effect to be replicable. The qualitative evaluation of the pharmacodynamic action of those preparations was a condition for their further quantitative pharmacological evaluation in point of antitumoral therapeutic effectiveness in a preclinical stage.

Animals↗
PubMedDate not supplied

Preclinical trial of the antitumoral therapeutic effectiveness of some natural polyphenolic biopreparations.

We have assessed the antitumoral action of the POLYAS I and POLYAS II vegetal polyphenolic biopreparations--separated and purified from Asclepias syriaca leaves - in rats with various experimental tumoral lines. We studied the therapeutic effect of different doses on the tumor generation process and compared it with the experimental oncostatic action of several standard chemotherapeutic drugs of clinical use (thiotepa, methotrexate, melphalan and cyclophosphamide). In our experimental treatment with the bioactive polyphenolic agents, we have used various doses, both higher and lower than the dose that had conditioned the expression of their antitumoral action upon Guerin T-8 lymphotropic epithelioma and upon Walker 256 carcinosarcoma. We found the antineoplastic effectiveness of those aromatic biopreparations from phytomass to be dose-dependent. We compared the evaluation indices of the antitumoral pharmacodynamic effect we obtained in the treatment with the POLYAS biopreparations with those of reference cytostatic agents. The antitumoral potential of the new natural biopreparations is higher than, equal or close to that of the standard oncochemotherapeutic agents. Antitumoral effectiveness can be improved by an experimental manipulation of the therapeutic doses--which proves the existence of a dose-response relationship. POLYAS I and POLYAS II polyphenolic biopreparations are compatible in point of effectiveness with the standard cytostatic agents, a fact that we considered relevant for the characterization of the POLYAS I and POLYAS II vegetal extracts as potential antineoplastic agents. The quantitative preclinical evaluation of the specific pharmacodynamic effect will be complemented by the investigation of the new polyphenolic biopreparations therapeutic effectiveness in tumors with various degrees of development.

Animals↗