Factors Influencing the Regional Deposition of Inhaled Particles in Man

1983 ◽  
Vol 64 (1) ◽  
pp. 69-78 ◽  
Author(s):  
M. J. Chamberlain ◽  
W. K. C. Morgan ◽  
S. Vinitski
Keyword(s):  
Regional Differences ◽  
Particle Deposition ◽  
Normal Subjects ◽  
Radioactive Aerosol ◽  
Breathing Rate ◽  
Regional Ventilation ◽  
Inhaled Particles ◽  
Human Lungs ◽  
Regional Deposition ◽  
Normal Human

1. Although ventilation in normal human lungs has been shown to decrease from apex to base, comparable observations are lacking in regard to particle deposition. 2. We compared regional ventilation and particle deposition in normal subjects by using radioactive xenon and a radioactive aerosol while sitting, lying, and while breathing at an increased rate. Both smokers and non-smokers were studied. 3. Particle deposition and ventilation were closely related, and the greater the ventilation the greater the deposition of particles, a situation which prevailed irrespective of position and breathing rate. While supine, the apex to base gradient for both ventilation and particle deposition decreased but did not entirely disappear. At higher respiratory rates, central deposition of particles, especially in smokers, increased. 4. We concluded that there are regional differences in the deposition of particles and that such differences are closely related to regional ventilation.

Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method

1996 ◽  
Vol 81 (5) ◽  
pp. 2203-2213 ◽  
Author(s):  
Chong S. Kim ◽  
S. C. Hu ◽  
P. Dewitt ◽  
T. R. Gerrity
Keyword(s):  
Particle Diameter ◽  
Deposition Efficiency ◽  
Dead Volume ◽  
Delivery Method ◽  
Constant Flow Rate ◽  
Inhaled Particles ◽  
Human Lungs ◽  
Regional Deposition ◽  
Delivery Technique ◽  
Deposition Fraction

Kim, Chong S., S. C. Hu, P. DeWitt, and T. R. Gerrity.Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method. J. Appl. Physiol. 81(5): 2203–2213, 1996.—Detailed regional deposition of inhaled particles was investigated in young adults ( n = 11) by use of a serial bolus aerosol delivery technique. A small bolus (45 ml half-width) of monodisperse aerosols [1-, 3-, and 5-μm particle diameter ( D p)] was delivered sequentially to a specific volumetric depth of the lung (100–500 ml in 50-ml increments), while the subject inhaled clean air via a laser aerosol photometer (25-ml dead volume) with a constant flow rate (Q˙ = 150, 250, and 500 ml/s) and exhaled with the same Q˙ without a pause to the residual volume. Deposition efficiency (LDE) and deposition fraction in 10 local volumetric regions and total deposition fraction of the lung were obtained. LDE increased monotonically with increasing lung depth for all three D p. LDE was greater with smaller Q˙ values in all lung regions. Deposition was distributed fairly evenly throughout the lung regions with a tendency for an enhancement in the distal lung regions for D p = 1 μm. Deposition distribution was highly uneven for D p = 3 and 5 μm, and the region of the peak deposition shifted toward the proximal regions with increasing D p. Surface dose was 1–5 times greater in the small airway regions and 2–17 times greater in the large airway regions than in the alveolar regions. The results suggest that local or regional enhancement of deposition occurs in healthy subjects and that the local enhancement can be an important factor in health risk assessment of inhaled particles.

Use of aerosols to estimate pulmonary air-space dimensions

1981 ◽  
Vol 51 (2) ◽  
pp. 465-476 ◽  
Author(s):  
J. Gebhart ◽  
J. Heyder ◽  
W. Stahlhofen
Keyword(s):  
Particle Deposition ◽  
Continuous Monitoring ◽  
Region Of Interest ◽  
Normal Subjects ◽  
Breath Holding ◽  
Experimental Conditions ◽  
Single Breath ◽  
Inhaled Particles ◽  
Respiratory Flow ◽  
Air Space

Single-breath inhalations of monodisperse aerosols were performed with a group of normal subjects to determine aerosol recovery from the human lung after periods of breath holding. Aerosols of monodisperse nonhygroscopic droplets of bis(2-ethylhexyl) sebacate of between 0.5 and about 2.5 micron diam were used for the inhalation. The inhalation apparatus allows continuous monitoring of particle number concentration and flow rate close to the mouth. Experiments were designed to find the optimum experimental conditions for the principal concept of Palmes et al (In: Inhaled Particles and Vapours. London: Pergamon, 1976, vol. II. p. 339-347) to evaluate pulmonary air-space dimensions by means of aerosols. The experimental results obtained for various respiratory flow rates (125, 250, and 500 cm3 X s-1), settling velocities of the particles (10(-3) to 1.5 X 10(-2) cm X s-1) and volumes of inspired aerosols (500, 1,000, and 2,000 cm3) are compared with the results derived from a mathematical model for the particle deposition during respiratory pauses. Monodisperse aerosols with particles between 1 and about 1.5 micron diam. inspired for breath holding into the lung region of interest, may provide optimum conditions for the sizing of air spaces by means of aerosols.

Calculated deposition of inhaled particles in the airway generations of normal subjects

1979 ◽  
Vol 47 (4) ◽  
pp. 867-873 ◽  
Author(s):  
T. R. Gerrity ◽  
P. S. Lee ◽  
F. J. Hass ◽  
A. Marinelli ◽  
P. Werner ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Surface Concentration ◽  
Normal Subjects ◽  
Lung Model ◽  
Iron Oxide Particles ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Oxide Particles ◽  
Predicted Values ◽  
Good Agreement

Detailed regional deposition of inhaled particles in the human lung is calculated for individual airway generations. The calculations are based on Landahl's deposition model as applied to the morphometric lung model of Weibel. We consider primarily deposition patterns of iron oxide particles with diameters ranging between 1 and 10 micrometers, but we also calculate patterns of deposition for bis(2-ethylhexyl) sebacate particles with diameters as small as 0.2 micrometers. We obtain good agreement between predicted values and observed values for alveolar retention of inhaled iron oxide particles with 64 and 20% of total deposition predicted to occur in nonciliated airways for 2- and 5-micrometer particles, respectively. This is compared with 48 +/- 9 and 27 +/- 10% for the measured values. Calculated values for total lung deposition of small bis(2-ethylhexyl) sebacate particles agree well with experimental data. The calculations show a minimum in deposition occurring for particle diameters of 0.5 micrometers, which is in agreement with observations. A calculation of surface concentration of deposited 7.9-micrometer aerodynamic particles reveals a very large concentration occurring at airway generation four. This observation is considered in light of observations that bronchial carcinomas occur in this vicinity of the lung.

Human variation in the peripheral air-space deposition of inhaled particles

1987 ◽  
Vol 62 (4) ◽  
pp. 1603-1610 ◽  
Author(s):  
W. D. Bennett ◽  
G. C. Smaldone
Keyword(s):  
Particle Deposition ◽  
Hold Time ◽  
Normal Subjects ◽  
Breath Hold ◽  
Inhaled Particles ◽  
Space Size ◽  
Air Space ◽  
Deposition Fraction ◽  
Lung Periphery ◽  
Conducting Airways

Intersubject variability in both peripheral air-space dimensions and breathing pattern [tidal volume (VT) and respiratory frequency (f)] may play a role in determining intersubject variation in the fractional deposition of inhaled particles that primarily deposit in the lung periphery (i.e., distal to conducting airways). In healthy subjects breathing spontaneously at rest, we measured the deposition fraction (DF) of a 2.6-microns monodisperse aerosol by Tyndallometry while simultaneous measurement of VT and f were made. Under these conditions particle deposition occurs primarily in the peripheral air spaces of the lung. As an index of peripheral air-space size, we used measurements of aerosol recovery (RC) as a function of breath-hold time (t) (Gebhart et al. J. Appl. Physiol. 51: 465–476, 1981). In each subject, we measured RC (aerosol expired/aerosol inspired) of a 1.0-micron monodisperse aerosol as a function of breath-hold time for inspiratory capacity breaths of aerosol. The half time (t1/2) (the breath-hold time to reach 50% RC with no breath hold) is proportional to a mean diameter (D) of air spaces filled with aerosol. In the 10 subjects studied, we found a variable DF, range 0.04–0.44 [0.25 +/- 0.12 (SD)]. DF correlated most closely with 1/f, or the period of breathing (r = 0.96, P less than 0.01). There was no significant correlation between DF and t1/2 as an index of peripheral air-space size. In fact there was little deviation in t1/2 in these normal subjects [coefficient of variation (CV) = 0.12].(ABSTRACT TRUNCATED AT 250 WORDS)

Regional deposition of inhaled particles in human lungs: comparison between men and women

1998 ◽  
Vol 84 (6) ◽  
pp. 1834-1844 ◽  
Author(s):  
Chong S. Kim ◽  
S. C. Hu
Keyword(s):  
Particle Deposition ◽  
Fine Particles ◽  
Particle Diameter ◽  
Flow Rates ◽  
Men And Women ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Delivery Technique ◽  
Deposition Fraction ◽  
The Difference

We measured detailed regional deposition patterns of inhaled particles in healthy adult male ( n = 11; 25 ± 4 yr of age) and female ( n = 11; 25 ± 3 yr of age) subjects by means of a serial bolus aerosol delivery technique for monodisperse fine [particle diameter ( D p) = 1 μm] and coarse aerosols ( D p = 3 and 5 μm). The bolus aerosol (40 ml half-width) was delivered to a specific volumetric depth (Vp) of the lung ranging from 100 to 500 ml with a 50-ml increment, and local deposition fraction (LDF) was assessed for each of the 10 local volumetric regions. In all subjects, the deposition distribution pattern was very uneven with respect to Vp, showing characteristic unimodal curves with respect to particle size and flow rate. However, the unevenness was more pronounced in women. LDF tended to be greater in all regions of the lung in women than in men for D p = 1 μm. For D p = 3 and 5 μm, LDF showed a marked enhancement in the shallow region of Vp ≤ 200 ml in women compared with men ( P < 0.05). LDF in women was comparable to or smaller than those of men in deep lung regions of Vp > 200 ml. Total lung deposition was comparable between men and women for fine particles but was consistently greater in women than men for coarse particles regardless of flow rates used: the difference ranged from 9 to 31% and was greater with higher flow rates ( P < 0.05). The results indicate that 1) particle deposition characteristics differ between healthy men and women under controlled breathing conditions and 2) deposition in women is greater than that in men.

Effect of exercise on deposition and subsequent retention of inhaled particles

1985 ◽  
Vol 59 (4) ◽  
pp. 1046-1054 ◽  
Author(s):  
W. D. Bennett ◽  
M. S. Messina ◽  
G. C. Smaldone
Keyword(s):  
Particle Deposition ◽  
Human Subjects ◽  
Regional Distribution ◽  
Bicycle Ergometer ◽  
Inhaled Particles ◽  
Significant Difference ◽  
Lung Retention ◽  
Deposition Fraction ◽  
Normal Human ◽  
Rest And Exercise

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.

scholarly journals Increase in relative deposition of fine particles in the rat lung periphery in the absence of gravity

2014 ◽  
Vol 117 (8) ◽  
pp. 880-886 ◽  
Author(s):  
Chantal Darquenne ◽  
Maria G. Borja ◽  
Jessica M. Oakes ◽  
Ellen C. Breen ◽  
I. Mark Olfert ◽  
...  
Keyword(s):  
Particle Deposition ◽  
Fine Particles ◽  
Left Lung ◽  
Retention Rates ◽  
Inhaled Particles ◽  
Regional Deposition ◽  
Research Aircraft ◽  
The Difference ◽  
Magnetic Resonance Imaging Mri ◽  
Lung Periphery

While it is well recognized that pulmonary deposition of inhaled particles is lowered in microgravity (μG) compared with gravity on the ground (1G), the absence of sedimentation causes fine particles to penetrate deeper in the lung in μG. Using quantitative magnetic resonance imaging (MRI), we determined the effect of gravity on peripheral deposition (DEPperipheral) of fine particles. Aerosolized 0.95-μm-diameter ferric oxide particles were delivered to spontaneously breathing rats placed in plethysmographic chambers both in μG aboard the NASA Microgravity Research Aircraft and at 1G. Following exposure, lungs were perfusion fixed, fluid filled, and imaged in a 3T MR scanner. The MR signal decay rate, R2*, was measured in each voxel of the left lung from which particle deposition (DEP) was determined based on a calibration curve. Regional deposition was assessed by comparing DEP between the outer (DEPperipheral) and inner (DEPcentral) areas on each slice, and expressed as the central-to-peripheral ratio. Total lung deposition tended to be lower in μG compared with 1G (1.01 ± 0.52 vs. 1.43 ± 0.52 μg/ml, P = 0.1). In μG, DEPperipheral was larger than DEPcentral ( P < 0.03), while, in 1G, DEPperipheral was not significantly different from DEPcentral. Finally, central-to-peripheral ratio was significantly less in μG than in 1G ( P ≤ 0.05). These data show a larger fraction of fine particles depositing peripherally in μG than in 1G, likely beyond the large- and medium-sized airways. Although not measured, the difference in the spatial distribution of deposited particles between μG and 1G could also affect particle retention rates, with an increase in retention for particles deposited more peripherally.

IMMUNOLOGICAL REACTIVITY OF INSULIN IN HUMAN SERUM

1966 ◽  
Vol 53 (4) ◽  
pp. 673-680 ◽  
Author(s):  
Torsten Deckert ◽  
Kai R. Jorgensen
Keyword(s):  
Normal Subjects ◽  
The Other ◽  
Human Pancreas ◽  
Porcine Pancreas ◽  
Crystalline Insulin ◽  
Endogenous Insulin ◽  
Significant Difference ◽  
Human Sera ◽  
Normal Human ◽  
The One

ABSTRACT The purpose of this study was to investigate whether a difference could be demonstrated between crystalline insulin extracted from normal human pancreas, and crystalline insulin extracted from bovine and porcine pancreas. Using Hales & Randle's (1963) immunoassay no immunological differences could be demonstrated between human and pig insulin. On the other hand, a significant difference was found, between pig and ox insulin. An attempt was also made to determine whether an immunological difference could be demonstrated between crystalline pig insulin and crystalline human insulin from non diabetic subjects on the one hand and endogenous, circulating insulin from normal subjects, obese subjects and diabetic subjects on the other. No such difference was found. From these experiments it is concluded that endogenous insulin in normal, obese and diabetic human sera is immunologically identical with human, crystalline insulin from non diabetic subjects and crystalline pig insulin.

Aerosol deposition in the human lung: Effect of high-frequency oscillation on the deposition characteristics of an inhaled nebulized aerosol

1988 ◽  
Vol 75 (5) ◽  
pp. 535-542 ◽  
Author(s):  
Simon H. L. Thomas ◽  
Jackie A. Langford ◽  
Robert J. D. George ◽  
Duncan M. Geddes
Keyword(s):  
Deposition Rate ◽  
High Frequency ◽  
Regional Distribution ◽  
Normal Subjects ◽  
Aerosol Deposition ◽  
High Frequency Oscillation ◽  
Particle Sizes ◽  
Frequency Oscillation ◽  
Regional Deposition ◽  
Peripheral Lung

1. Oral high-frequency oscillation (OHFO) may have important effects on aerosol deposition in the lungs. In order to investigate these, a technique was devised to measure regional deposition rates of a nebulized radio-labelled aerosol in the lungs during normal tidal breathing. 2. The effect of three frequencies of OHFO on pulmonary aerosol deposition rate (PADR) in four normal subjects and five patients with chronic airways obstruction (CAO) were assessed using the technique. 3. In separate experiments employing three normal subjects, the effect of OHFO was studied on the deposition rate of aerosol on the oropharynx and delivery apparatus, and on the amount and characteristics of aerosol inhaled by the subjects. 4. Total PADR was significantly reduced by OHFO at 8 Hz and 16 Hz in the normal subjects, and by all three frequencies of OHFO in the CAO patients. In the normal subjects, the regional distribution of aerosol deposition was unchanged, but in the CAO patients a larger proportion of total aerosol deposition occurred in peripheral lung. 5. OHFO reduced the oropharyngeal aerosol deposition rate, increased the loss of aerosol to the atmosphere before inhalation, and increased the deposition of aerosol on the delivery apparatus. The end result was a reduction in the amount of aerosol inhaled, and in the particle sizes measured at the mouthpiece. 6. We conclude that OHFO reduces the amount of aerosol inhaled, but may improve peripheral deposition of inhaled aerosol in patients with CAO. This effect may be of value in the clinical administration of nebulized drugs.

Viscosity of normal human blood under normothermic and hypothermic conditions

1964 ◽  
Vol 19 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Peter W. Rand ◽  
Eleanor Lacombe ◽  
Hamilton E. Hunt ◽  
William H. Austin
Keyword(s):  
Blood Flow ◽  
Shear Rate ◽  
Heart Surgery ◽  
Blood Rheology ◽  
Normal Subjects ◽  
Future Studies ◽  
Flow Impedance ◽  
Normal Human ◽  
Technical Details ◽  
Normal Human Blood

Although blood viscosity varies in relation to shear rate, hematocrit, and temperature, equipment is now available with which it may be measured in respect to each of these variables. A simple, clinically practical technique for such measurement is presented. Blood from 60 normal subjects was adjusted to hematocrits 0, 20, 40, 60, and 80, and the viscosity-shear rate relationships measured at 37.0, 32.0, 27.0, and 22.0 C. The data obtained are presented as a reference for future studies using this method. Technical details are discussed and some deserving areas of application are considered. shear rate; cone-plate viscometer; hematocrit-viscosity relationships; blood, plasma; hematocrit; temperature; blood flow impedance; perfusion; shock; oliguria; dyspnea; coma; heart surgery; blood rheology; metabolism Submitted on May 31, 1963

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