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Biomedical subjects

M S Messina

Publications and source records attributed to M S Messina.

11 recordsLinked to original sources
PubMed1993

Regional impairment of mucociliary clearance in chronic obstructive pulmonary disease.

Asthmatic subjects with tidal expiratory flow limitation have mucociliary clearance (MC) impairment in central airways. Because tidal flow limitation develops in COPD, it is possible that regional MC in these patients also may be affected. We tested this hypothesis by measuring MC in the presence or absence of flow limitations. Patients with COPD and chronic flow limitation were compared with non-flow-limited normal volunteers. Deposition was normalized for regional lung volume and expressed as the specific central to peripheral (sC/P) ratio. In COPD subjects, clearance from the whole lung and central airways was significantly different from that of normal subjects after 20 min of observation. In the peripheral airways, there were no significant differences between COPD and normal subjects. An alternative analysis of regional MC indicated patients retained particles in central airways while normal subjects, with intact MC, emptied central airways. Thus, COPD subjects with tidal expiratory flow limitation have impaired MC in their central airways.

Adolescent↗
PubMed1991

Changes in mucociliary clearance during acute exacerbations of asthma.

Previous studies have suggested that mucociliary clearance (MC) is impaired in asthmatic subjects. If so, impaired clearance may be an important factor in acute exacerbation. We proposed that if MC plays a significant role in acute illness, MC should be impaired during the exacerbation but improve after recovery. To test this hypothesis, five asthmatic patients with attacks requiring hospitalization underwent measurement of MC using radiolabeled aerosol and a gamma camera. They were studied on the second or third day after admission with repeat measurements after discharge. Spirometry was performed before all studies. After an equilibrium xenon scan (133Xe), which defined lung borders and measured regional volume, radiolabeled saline particles containing technetium-labeled (99mTC) sulfur colloid were deposited and used to label airway mucus. Deposition patterns were matched by regulating particle distribution and breathing pattern. MC was then measured as percentage retention of radioactivity at 10-min intervals for 2 h. When hospitalized, 96.0 +/- 2.06% (SEM) of the initial radioactivity was retained in the lung after 2 h, indicating little clearance of mucus from the lung. In fact, no significant changes were detected when activity at 120 min was compared with measurements at 10 min (99.2 +/- 0.22%, NS). After discharge clearance was markedly enhanced. That is, retention of lung activity was significantly lower at all time intervals from 10 min onward, with only 70.9 +/- 3.86% retained at 120 min (p = 0.008). During an asthmatic attack warranting hospital admission, MC is significantly impaired, with marked improvement following recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1985

Evaluation of quantitative aerosol techniques for use in bronchoprovocation studies.

To investigate airway physiology by use of inhaled aerosols, it is frequently necessary to measure the actual amount of material deposited on the airway wall as well as the site of particle deposition. To satisfy these needs, radiolabeled aerosols and gamma camera techniques have been used to measure regional deposition of inhaled particles. To make quantitative measurements of the amount deposited, previous investigators have used a "phantom" technique to indirectly calibrate the gamma camera for the attenuation of gamma rays through the lungs and chest wall. For this calibration, the phantom is a simulated lung containing a known amount of radioactivity. Radioactive counts emitted from the phantom are assumed to be attenuated in the same manner as the intact human lung. The present article describes a technique to determine directly the amount of inhaled aerosol deposited in the lung and simultaneously to calibrate the gamma camera for each individual subject. We used right angle light scattering and a gamma camera to measure individual values of the deposition fraction (DF) of inhaled aerosol deposited in the lung and the coefficient of attenuation (AC) of gamma rays in normal and obstructed lungs of human subjects. Radiolabeled monodisperse aerosols 1 and 2 microns in diameter were used. Knowledge of the activity of the inhaled aerosol (microcurie per liter), the volume inhaled, and the measured DF determined each subject's AC (counts per minute per microcurie). DF varied by an order of magnitude in normal (0.04 to 0.48) and obstructed (0.16 to 0.75) of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Quantitative assays of pharmacologic aerosols used in studying asthma.

To more nearly accurately quantitate the dose of pharmacologic agents delivered to human and animal airways via aerosols, we have developed a monodisperse aerosol containing either methacholine or histamine that permits a light scattering device (tyndallometry) to measure accurately the quantity of inspired and expired particles. These aerosols (described in previous studies) are simultaneously tagged with a radioactive label (technetium 99m) to permit the use of external gamma camera imaging. Present work focuses on the development of assay techniques to measure the quantity of methacholine delivered in these aerosols. The lack of specific radioimmune or radioenzyme assays coupled with the cross-reaction of organic contaminants with conventional chemical reagents for measuring methacholine required the development of separative techniques to isolate the methacholine from the organic aerosol contaminants. With aqueous extraction and column separation we have been able to completely isolate the methacholine from these contaminants. This allows the application of standard spectrophotometric assays for methacholine to quantitate the methacholine in the resulting solution. These separative techniques will permit the use of these aerosols in quantitative studies of airway reactivity.

Aerosols↗
PubMed1985

Enhancement of particle deposition by flow-limiting segments in humans.

Severe chronic obstructive pulmonary disease is associated with central deposition of inhaled aerosols. This pattern may be due to functional narrowing of the large airways during expiration at flow-limiting segments (FLS). Using a gamma camera and 2.5-micron particles, we compared the pattern of aerosol deposition following quiet breathing with that after a controlled forced expiration (cough) when FLS are known to form in central airways. Lung size measurement by 133Xe allowed construction of regions of interest over the central airways and lung periphery. Deposition in these regions was normalized for area and lung thickness and expressed as a central-to-peripheral (C/P) ratio. In addition, using right-angle light scattering, the fraction of inhaled particles deposited with each breath (DF) was determined. During control studies, airflow and tidal volume were continuously monitored to insure that tidal loops were well below the maximum expiratory flow-volume (MEFV) curve. To create dynamic compression, cough was used to generate a partial MEFV curve, while inspiratory flow, tidal volume, and functional residual capacity were maintained close to quiet breathing. With cough, C/P ratios increased markedly from 1.04 +/- 0.18 to 2.21 +/- 0.61 (P less than 0.01, n = 6). DF for the lung and airways did not significantly change (0.43 +/- 0.11 to 0.45 +/- 0.09, P = NS). The greater enhancement of regional deposition in the central airways with deposition unchanged over the whole lung demonstrates that, during cough, peripheral deposition is actually reduced when compared with quiet breathing. We conclude that dynamic compression at FLS can be an important factor in the central deposition of inhaled particles.

Humans↗
PubMed1985

Flow limitation, cough, and patterns of aerosol deposition in humans.

We studied deposition of radioactive monodisperse 1.5-micron aerosol in humans following inhalation during quiet breathing. Two groups were studied: normal, defined by tidal loops below the maximum expiratory flow-volume (MEFV) envelope [forced expiratory volume at 1 s at percent of forced vital capacity (FEV1%) 62-78]; and flow-limited, with tidal loops superimposed on MEFV relationship (FEV1% 21-57) and flow-limiting segments (FLS) known to exist in central airways. During simultaneous imaging with a gamma camera, fraction of inhaled aerosol deposited in the lung (DF) was determined by right-angle light scattering. With regions of interest defined by an equilibrium image of 133Xe, regional deposition was normalized for area and lung thickness and expressed as a central-to-peripheral (C/P) ratio. Deposition was uniform throughout the lung in normal subjects [C/P 1.02 +/- 0.07 (SD), n = 6]. In flow-limited group, central deposition predominated (C/P 1.98 +/- 0.64, n = 6, P less than 0.05). Tidal volume and inspiratory flow, forces thought to influence deposition during inspiration, were not different between groups. Spontaneous cough occurred in five flow-limited subjects during aerosol inhalation, with further increase in central deposition when compared with quiet breathing (C/P 1.85 +/- 0.60 to 2.69 +/- 0.600, P less than 0.01). During cough, tidal volume (ml) was reduced significantly (576 +/- 151 to 364 +/- 117, P less than 0.01) with no change in inspiratory flow (l/s) (1.37 +/- 0.23 to 1.38 +/- 0.40, P = NS). DF, however, was unaffected by cough (0.34 +/- 0.13 to 0.61 +/- 0.12, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1985

Effect of exercise on deposition and subsequent retention of inhaled particles.

To investigate the effect of exercise and its associated increase in ventilation on the deposition and subsequent retention of inhaled particles, we measured the fractional and regional lung deposition of a radioactively tagged (99mTc) monodisperse aerosol (2.6 microns mass median aerodynamic diam) in normal human subjects at rest and while exercising on a bicycle ergometer. Breath-by-breath deposition fraction (DF) was measured throughout the aerosol exposures by Tyndallometry. Following each exposure gamma camera analysis was used to 1) determine the regional distribution of deposited particles and 2) monitor lung retention for 2.5 h and again at 24 h. We found that DF was unchanged between ventilation at rest (6-10 l/min) and exercise (32-46 l/min). Even though mouth deposition was enhanced with exercise, it was not large enough to produce a significant difference in the deposition fraction of the lung (DFL) between resting and exercise exposures. The central-to-peripheral distribution of deposited aerosol was larger for the exercise vs. resting exposure, reflecting a shift of particle deposition to more central bronchial airways. Apical-to-basal distribution was not different for the two exposures. Retention at 2.5 h and 24 h (R24) was reduced following the exercise vs. the resting exposure, consistent with greater bronchial deposition during exercise. The product of DFL and R24 gave a measure of fractional burden at 24 h (B24), i.e., the fraction of inhaled aerosol residing in the lungs 24 h after exposure. B24 was not significantly different between rest and exercise exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Carney's triad: role of transthoracic needle biopsy.

A triad of gastric epithelioid leiomyosarcoma, functioning extra-adrenal paraganglioma, and pulmonary chondroma, has been described in 7 patients, and a partial expression of this tumor complex consisting of 2 of the 3 tumors in at least 11 others. Sixteen of these 18 patients were female. The variable presentation and course of these patients warrants special attention. We present the nineteenth reported case: a 26-yr-old woman with a pulmonary chondroma and a gastric epithelioid leiomyosarcoma. It is suggested that in cases of this type thoracotomy may not be necessary for the diagnosis of the pulmonary chondroma, and extensive gastric resection of the leiomyosarcoma may be lifesaving.

Adult↗
PubMedDate not supplied

Retrospective study of bitolterol mesylate in the treatment of conditions associated with reversible bronchospasm.

Patients with reversible bronchospasm benefit from the use of inhaled beta-adrenergic agents. In this retrospective study of 24 older patients with a variety of conditions associated with reversible bronchospasm--asthma, asthma with emphysema, chronic bronchitis, and asthmatic bronchitis--symptomatic improvement was noted after treatment with inhaled bitolterol mesylate. Symptoms resolved or improved after 1 month in 93.8% (15/16) of patients using a metered-dose inhaler and in 75% (6/8) of those using a hand-held nebulizer. Sixteen additional patients were randomly selected to undergo pulmonary function tests after receiving two to three puffs of bitolterol from a metered-dose inhaler. FEV1 improved by 10.9%, FVC by 12.1%, and FEF25%-75% by 34.4% after administration of bitolterol. No adverse events were noted in any patients in either group. The results of this retrospective study suggest that bitolterol is an effective and safe treatment in patients with conditions associated with reversible bronchospasm.

Administration, Inhalation↗