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.

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.

Cerebral metabolism of isotopic glucose in chronic mental disease

1959 ◽  
Vol 14 (5) ◽  
pp. 849-854 ◽  
Author(s):  
William Sacks
Keyword(s):  
Mental Disease ◽  
Cerebral Metabolism ◽  
Human Subjects ◽  
Psychiatric Patients ◽  
Normal Subjects ◽  
Main Site ◽  
Significant Difference ◽  
Normal Human ◽  
Average Activity ◽  
Theoretical Considerations

A previous investigation of cerebral metabolism of isotopic glucose in normal human subjects was extended and similar studies performed upon chronic psychiatric patients. With variously labeled glucose-C14 as substrates, average activity-time curves and values for cumulative C14O2 resulting from cerebral oxidation of labeled glucose showed no significant variations between normal and psychotic subjects. A significant difference (P < 0.02) between the two groups did occur in comparing the fraction of brain CO2 derived from glucose. Calculations using individual glucose-U-C14 experiments gave averages of 56% for normal subjects and 36% for mental patients. These values agreed with those derived from composite curves of variously labeled glucose. That less brain CO2 was derived from glucose in psychotic subjects seemed to indicate a greater dilution of some carbohydrate intermediate(s) by protein and/or lipid intermediate(s); and, possibly, a decreased cerebral oxidation of carbohydrate. Theoretical considerations suggested that pyruvate and/or lactate might be the main site(s) of dilution. Submitted on January 28, 1959

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.

scholarly journals Effects of melatonin ingestion on cAMP and cGMP levels in human plasma

1999 ◽  
Vol 163 (3) ◽  
pp. 457-462 ◽  
Author(s):  
IV Zhdanova ◽  
DJ Raz
Keyword(s):  
Platelet Rich Plasma ◽  
Human Subjects ◽  
Placebo Treatment ◽  
Promoting Effect ◽  
Melatonin Treatment ◽  
Significant Difference ◽  
Normal Human ◽  
The Mean ◽  
Camp Levels ◽  
Camp And Cgmp

The effects of daytime melatonin treatment (0.3 mg) on cAMP and cGMP levels in platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were investigated in 14 normal human subjects (age+/-s.e.m. 26.2+/-3. 2 years). Plasma levels of cAMP, cGMP and melatonin were measured before and at intervals for 3 h after the treatment was administered at 1300 h. Plasma melatonin concentrations reached peak levels 1 h after the treatment (mean+/-s.d. 182.3+/-43.5 pg/ml). The mean areas under the curve (AUC) for the time-cGMP concentration curves in PPP and in PRP were significantly increased after melatonin treatment compared with those observed after placebo treatment (P=0.001). No significant difference in cGMP levels was observed between PPP and PRP. Increase in self-reported sleepiness after melatonin treatment positively correlated with increase in plasma cGMP levels (r=0.92). The mean AUC for the time-cAMP concentration in PRP, but not in PPP, was increased 1 h after melatonin treatment compared with that observed after placebo treatment, but not thereafter. No correlation between individual PRP or PPP cAMP levels and subjective sleepiness was observed. These results demonstrate a stimulating effect of melatonin treatment on plasma cGMP levels in humans and suggest a correlation between the increase in circulating cGMP levels and the sleep-promoting effect of the pineal hormone.

Signals consistent with microbubbles detected in legs of normal human subjects after exercise

2010 ◽  
Vol 108 (2) ◽  
pp. 240-244 ◽  
Author(s):  
J. C. Wilbur ◽  
S. D. Phillips ◽  
T. G. Donoghue ◽  
D. L. Alvarenga ◽  
D. A. Knaus ◽  
...  
Keyword(s):  
Human Subjects ◽  
Bicycle Ergometer ◽  
Left Thigh ◽  
Maximal Heart Rate ◽  
Dual Frequency ◽  
Ultrasound Technique ◽  
Nucleation Sites ◽  
Normal Human ◽  
Decompression Stress ◽  
Frequency Ultrasound

Exercise may produce micronuclei (presumably gas-filled bubbles) in tissue, which could serve as nucleation sites for bubbles during subsequent decompression stress. These micronuclei have never been directly detected in humans. Dual-frequency ultrasound (DFU) is a resonance-based, ultrasound technique capable of detecting and sizing small stationary bubbles. We surveyed for bubbles in the legs of six normal human subjects (ages 28–52 yr) after exercise using DFU. Eleven marked sites on the left thigh and calf were imaged using standard imaging ultrasound. Subjects then rested in a reclining chair for 2 h before exercise. For the hour before exercise, a series of baseline measurements was taken at each site using DFU. At least six baseline measurements were taken at each site. Subjects exercised at 80% of their age-adjusted maximal heart rate for 30 min on an upright bicycle ergometer. After exercise, the subjects returned to the chair, and multiple postexercise measurements were taken at the marked sites. Measurements continued until no further signals consistent with bubbles were returned or 1 h had elapsed. All subjects showed signals consistent with bubbles after exercise at at least one site. The percentage of sites in a given subject showing signals significantly greater than baseline ( P < 0.01) at first measurement ranged from 9.1 to 100%. Overall, 58% of sites showed signals consistent with bubbles at the first postexercise measurement. Signals decreased over time after exercise. These data strongly suggest that exercise produces bubbles detectable using DFU.

Observations on a Relationship between Steroid Metabolism and the Concentration of Plasma Fibrinogen

1963 ◽  
Vol 10 (02) ◽  
pp. 400-405 ◽  
Author(s):  
B. A Amundson ◽  
L. O Pilgeram
Keyword(s):  
Blood Coagulation ◽  
Methyl Ether ◽  
Broad Spectrum ◽  
Human Subjects ◽  
Plasma Fibrinogen ◽  
Steroid Metabolism ◽  
Specific Site ◽  
Chain Reaction ◽  
Normal Human ◽  
A Chain

SummaryEnovid (5 mg norethynodrel and 0.075 mg ethynylestradiol-3-methyl ether) therapy in young normal human subjects causes an increase in plasma fibrinogen of 32.4% (P >C 0.001). Consideration of this effect together with other effects of Enovid on the activity of specific blood coagulatory factors suggests that the steroids are exerting their effect at a specific site of the blood coagulation and/or fibrinolytic system. The broad spectrum of changes which are induced by the steroids may be attributed to a combination of a chain reaction and feed-back control.

Relationship Between Mepacrine-Labelled Dense Body Number, Platelet Capacity to Accumulate 14C-5-HT and Platelet Density in the Bernard-Soulier and Hermansky-Pudlak Syndromes

1979 ◽  
Vol 42 (02) ◽  
pp. 694-704 ◽  
Author(s):  
F Rendu ◽  
A T Nurden ◽  
M Lebret ◽  
J P Caen
Keyword(s):  
Dense Body ◽  
Human Subjects ◽  
Human Platelets ◽  
Dense Bodies ◽  
Storage Organelle ◽  
Hereditary Disorders ◽  
Labelling Procedure ◽  
Normal Human ◽  
Hermansky Pudlak Syndrome ◽  
Bernard Soulier Syndrome

SummaryWe have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 ± 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients’ platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bemard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.

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.

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