Ozone uptake in the intact human respiratory tract:  relationship between inhaled dose and actual dose

Inhaled concentration (C), minute volume (MV), and exposure duration (T) are factors that may affect the uptake of ozone (O3) within the respiratory tract. Ten healthy adult nonsmokers participated in four sessions, inhaling 0.2 or 0.4 ppm O3 through an oral mask while exercising continuously to elicit a MV of 20 l/min for 60 min or 40 l/min for 30 min. In each session, fractional absorption (FA) was determined on a breath-by-breath basis as the ratio of O3 uptake to the inhaled O3 dose. The mean ± SD value of FA for all breaths was 0.86 ± 0.06. Although C, MV, and T all had statistically significant effects on FA ( P < 0.0001, P = 0.004, and P = 0.026, respectively), the magnitudes of these effects were small compared with intersubject variability. For an average subject, a 0.05 change in FA would require that C change by 1.3 ppm, MV change by 46 l/min, or T change by 1.7 h. It is concluded that inhaled dose is a reasonable surrogate for the actual dose delivered to a particular subject during O3 exposures of <2 h, but it is not a reasonable surrogate when comparisons are made between individuals.

Download Full-text

Bronchoscopic determination of ozone uptake in humans

Journal of Applied Physiology ◽

10.1152/jappl.1995.79.3.852 ◽

1995 ◽

Vol 79 (3) ◽

pp. 852-860 ◽

Cited By ~ 11

Author(s):

T. R. Gerrity ◽

F. Biscardi ◽

A. Strong ◽

A. R. Garlington ◽

J. S. Brown ◽

...

Keyword(s):

Respiratory Tract ◽

Ozone Concentration ◽

Pairwise Comparisons ◽

Human Respiratory Tract ◽

Vocal Cords ◽

Male And Female ◽

Ozone Uptake ◽

Uptake Efficiency ◽

Response Characteristics

Measurements of ozone uptake efficiency in the human respiratory tract provide critical information toward understanding ozone dose-response characteristics. We measured ozone uptake efficiency by different regions of the respiratory tract between the mouth and bronchus intermedius in 10 healthy, resting, nonsmoking male and female subjects. The distal end of a bronchoscope was sequentially positioned at the bronchus intermedius (BI), main carina (CAR), upper trachea, and above the vocal cords. Ozone concentration was measured continuously at each sight using a rapid-responding ozone analyzer. During sampling subjects breathed through a mouthpiece connected to a pneumotachograph at a paced rate of 12 breaths/min. Integration of the product of the flow and ozone concentrations during inspiration and expiration provided the ozone mass passing each anatomic location during each phase of respiration. On inspiration the uptake efficiencies of ozone by structures between the mouth and each location j (Em-j) were 0.176 +/- 0.037 (SE), 0.271 +/- 0.024, 0.355 +/- 0.030, and 0.325 +/- 0.031 for above the vocal cords, upper trachea, CAR, and BI, respectively. A significant effect of location on Em-j was found by analysis of variance (P < 0.0002). Pairwise comparisons showed that Em-j increased as the lung penetration increased except between CAR and BI, which was not significantly different.

Download Full-text

EARLY VARIATIONS OF PLASMA CORTISOL AFTER PULSE INTRAVENOUS INJECTION OF DIBUTYRYL CYCLIC ADENOSINE 3′,5′-MONOPHOSPHATE IN NORMAL SUBJECTS

Acta Endocrinologica ◽

10.1530/acta.0.0720753 ◽

1973 ◽

Vol 72 (4) ◽

pp. 753-761 ◽

Cited By ~ 3

Author(s):

Alberto Angeli ◽

Giuseppe Boccuzzi ◽

Roberto Frajria ◽

Daniela Bisbocci ◽

Franco Ceresa

Keyword(s):

Intravenous Injection ◽

Plasma Cortisol ◽

Time Course ◽

Healthy Adult ◽

Normal Subjects ◽

Adult Women ◽

Healthy Women ◽

Adrenal Steroidogenesis ◽

The Mean ◽

Zero Time

ABSTRACT 10 mg/kg of dibutyryl cyclic adenosine 3′,5′-monophosphate (Db-cAMP) was iv pulse injected into twelve healthy adult women. The plasma cortisol levels were determined as 11-OHCS at zero time and then at 2.5, 5, 7.5, 10, 15, 30, 60 and 180 min after the injection. The data were compared with those obtained at the corresponding times in two groups of eleven and seventeen healthy women after the injection of 250 ng and 250 μg of synthetic β-1-24 corticotrophin performed in the same manner as the injection of the nucleotide. The mean increments in plasma cortisol were significantly lower after Db-cAMP than after ACTH. Differences were noted by analyzing the time course of the responses. In the case of stimulation with Db-cAMP the 11-OHCS levels rose progressively to a maximum at 15–30 min. By contrast, a peak of plasma cortisol was evident in most cases within a few min after the injection of ACTH; after a fall, a later rise was then observed starting from 15 min. The differences in the plasma 11-OHCS responses after the two stimuli may also be of interest clinically for the investigation of some aspects of adrenal steroidogenesis.

Download Full-text

A model for deposition of stable and unstable aerosols in the human respiratory tract

AIHAJ ◽

10.1080/15298667991430703 ◽

1979 ◽

Vol 40 (12) ◽

pp. 1055-1066 ◽

Cited By ~ 7

Author(s):

E. AUSTIN ◽

J. BROCK ◽

E. WISSLER

Keyword(s):

Respiratory Tract ◽

Human Respiratory Tract

Download Full-text

Numerical assessment of natural respiration and particles deposition in the computed tomography scan airway with a glomus tumour

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211024063 ◽

2021 ◽

pp. 095440892110240

Author(s):

Digamber Singh

Keyword(s):

Computed Tomography ◽

Respiratory Tract ◽

Particle Deposition ◽

Flow Characteristics ◽

Glomus Tumour ◽

Computed Tomography Scan ◽

Human Respiratory Tract ◽

Airflow Pattern ◽

Human Airways ◽

Tomography Scan

The human respiratory tract has a complex airflow pattern. If any obstruction is present in the airways, it will change the airflow pattern and deposit particles inside the airways. This is the concern of breath quality (inspired air), and it is decreasing due to the unplanned production of material goods. This is a primary cause of respiratory illness (asthma, cancer, etc.). Therefore, it is important to identify the flow characteristics in the human airways and airways with a glomus tumour with particle deposition. A numerical diagnosis is presented with an asymmetric unsteady-state light breathing condition (10 l/min). An in vitro human respiratory tract model has been reconstructed using computed tomography scan techniques and an artificial glomus tumour developed 2 cm above a carina on the posterior wall of the trachea. The transient flow characteristics are numerically simulated with a realizable (low Reynolds number) k–ɛ turbulence model. The flow disturbance is captured around the tumour, which influenced the upstream and downstream of the flow. The flow velocity pattern, wall shear stress and probable area of inflammation (hotspot) due to suspended particle deposition are determined, which may assist doctors more effectively in aerosol therapy and prosthetics of human airways illness.

Download Full-text