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Biomedical subjects

M Dolovich

Publications and source records attributed to M Dolovich.

At least 55 records · Page 3Linked to original sources
PubMed1986

Aerosol therapy of asthma: principles and applications.

Aerosols are the mainstay of therapy of reversible airflow obstruction. Currently available aerosols include bronchodilators such as beta-adrenoceptor agonists and anticholinergic agents which may be used alone or together with prophylactic, anti-inflammatory medications such as sodium cromoglycate and steroids. These agents are characterized by primarily topical activity and thus result in minimal systemic effects. By combining these medications in optimum doses, most patients can be readily managed. In patients with severe airway hyperreactivity, aerosols may need to be combined with oral sustained-release theophylline compounds and/or systemic steroids, the latter being used in minimum doses and if possible on alternate days to minimize adrenal suppression and steroid-related systemic complications. In recent years, an improved understanding of aerosol physics, pharmacology and airway physiology has led to greatly improved aerosol therapy with increasing emphasis on metered dose inhalers as the delivery system of choice while nebulizers are used less frequently except in hospital and pediatric applications. The use of intermittent positive-pressure devices for aerosol delivery has decreased considerably as physicians recognize that simpler delivery methods work equally well at much lower cost. While aerosol therapy techniques are now well worked out, research is continuing on methods of improving the efficiency of aerosol delivery and in the development of newer pharmacological agents such as longer-acting adrenoceptor agonists, calcium channel blockers, antagonists of mediators derived from arachidonic acid as well as higher dose aerosolized steroids.

Aerosols↗
PubMed1986

Optimal use of MDIs.

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Administration, Intranasal↗
PubMed1985

Ventilation scanning with technetium labeled aerosols. DTPA or sulfur colloid?

We have compared the distribution in the lungs of submicronic aerosols of either Tc-99m sulfur colloid or Tc-99m DTPA immediately after inhalation with the distribution 20 minutes later in 83 patients. Thirty-two of the 83 patients were active smokers. Of the 28 smokers who received Tc-99m DTPA aerosol, the total lung count fell by a mean of 27 +/- 14% between the 0 and 20 minute image. Eleven of these patients also had a major change in distribution of isotope during this time. In the nonsmoking patients total lung counts from Tc-99m DTPA fell by only 16 +/- 8% and none had a major change in distribution pattern. None of the smoking or non-smoking patients who received Tc-99m sulfur colloid had a significant change in count rate or distribution pattern over 20 minutes. The effects on the ventilation images of these rapid changes in count rate and distribution pattern after Tc-99m DTPA aerosol can be minimized by completing the ventilation study as quickly as possible after inhaling Tc-99m DTPA or by using a nondiffusible agent such as Tc-99m sulfur colloid.

Aerosols↗
PubMed1984

Lung epithelial permeability: relation to nonspecific airway responsiveness.

Lung epithelial permeability was measured in five normal, five asthmatic, and five smoking subjects by quantifying removal from the lung and accumulation in the blood of an inhaled radiolabeled low-molecular-weight substance, technetium-99m-labeled diethyleneaminepentaacetate (99mTc-DTPA). Measurements on 2 control days were highly reproducible. Nonspecific bronchial responsiveness to histamine was determined in all subjects on a 3rd day, and the results were expressed as the provocation concentration producing a fall in forced expiratory volume in 1 s of 20% (PC20 histamine). Lung epithelial permeability was similar for the normal and asthmatic subjects. However, smokers had greatly increased permeability when compared with the other two groups. The responsiveness to histamine was increased in the asthmatics but within the normal range for normal subjects and smokers. No relationship was established between increased epithelial permeability and increased responsiveness to histamine. Results indicate that increased permeability of the epithelial lining of the bronchi is not a dominant factor in the increased nonspecific responsiveness to histamine observed in asthma.

Adult↗
PubMed1983

Clinical evaluation of a simple demand inhalation MDI aerosol delivery device.

Inhalation of medication is the preferred method for treating reversible airway obstruction; however, difficulties in the use of pressurized canisters frequently lead to suboptimal results. The Aerochamber (Monoghan Medical Corp) is a portable breath-actuated device that attaches to a metered-dose inhaler (MDI) and is designed to overcome many of the problems of aerosol delivery encountered by some patients. The attachment of this breath-actuated device to an MDI reduced pharyngeal deposition of aerosol 14-fold, but delivery of aerosol to intrapulmonary airways in normal subjects and patients with bronchitis remained unchanged. In a group of nine patients with stable asthma, inhalation of a bronchodilator aerosol using the breath-actuated device (Aerochamber) achieved effective bronchodilation similar to an optimally administered MDI. Advantages of the breath-actuated device (Aerochamber) include (1) aerosol delivery of medication whether or not the discharge of aerosol is synchronized with inhalation, (2) effective therapeutic response compared with optimally administered MDI; (3) greatly reduced deposition of aerosol in the upper airways, which might be expected to reduce adverse effects of steroids; and (4) universal application to all bronchodilator and steroid MDIs.

Adult↗
PubMed1983

[Ventilation scintigraphy of the lung with 99mTc-DTPA or with 99mTc-sulfur colloid?].

Ventilation scintigraphy of the lung, obtained with sufficiently small 99mTc-labelled aerosol particles, provides an image of ventilation distribution that is acceptable in clinical routine. Whether 99mTc-DTPA or 99mTc-sulfur colloid is more suitable as a carrier was studied in 6 smokers and 8 non-smokers with chronic obstructive pulmonary disease. 99mTc-sulfur colloid was not absorbed by the bronchial mucosa and therefore appears to be an almost ideal agent. In contrast, 99mTc-DTPA was absorbed by the bronchial mucosa in all smoking patients more rapidly and inhomogenously than in non-smokers. The quantitative and qualitative comparison of the two dorsal ventilation scans taken both immediately after inhalation and 20 min later, showed in all 6 smoking patients after 20 min significant differences which influenced the diagnosis result. 99mTC-DTPA is therefore not recommended for use in ventilation lung scintigraphy, especially in smoking patients.

Adolescent↗
PubMed1975

Sulfur dioxide and tracheobronchial clearance in man.

Tracheobronchial clearance was measured in nine healthy, nonsmoking adults. Technetium Tc 99m albumin aerosol (mass median diameter, 3 mu; geometric standard deviation, 1.6) was inhaled as a bolus under controlled conditions to achieve reproducible deposition in large airways. Each subject was studied in three seperate three-hour experiments: twice under control conditions and once exposed to 5 ppm sulfur dioxide (pollutant exposure after aerosol inhalation). Lung retention of activity was measured using a gamma camera interfaced to a data storage and retrieval system. The study showed that (1) Both deposition and clearance were highly reproducible in individuals in repeat control studies. (2) Acute exposure to 5 ppm sulfur dioxide had no significant effect (P greater than .05) on mucocillary clearance in resting healthy subjects, except perhaps for a small transient change (P=.05) after one hour. (3) Pulmonary function tests showed a decrease in maximal midexpiratory flow (P less than .01) but no other significant changes.

Adult↗