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Biomedical subjects

D F Proctor

Publications and source records attributed to D F Proctor.

At least 19 recordsLinked to original sources
PubMed1983

The naso-oro-pharyngo-laryngeal airway.

Many of the muscles affecting the caliber of the upper airways have been shown to undergo a change in tone rhythmically timed to fit the breathing cycle. Failure in this function can adversely affect airway patency as in sleep-apnea. In normal persons the action of these muscles stabilizes the upper airways in a manner analagous to the action of the intercostals on the intrathoracic portion of the breathing apparatus. An important subject for future investigation is the exact nature of the nervous pathways involved.

Humans↗
PubMed1979

Effects of temperature, relative humidity, and mode of breathing on canine airway secretions.

Airway secretions were collected from the upper trachea of eight healthy nosebreathing mongrel dogs under general anesthesia, and the electrolytes and osmolality of these secretions were determined. Compared to plasma, secretions contained 15% higher Na+ and 33% higher Cl-, were 18% higher in osmolality, but had a lower Na+/Cl- throughout the 6-h experiments. When six nose-breathing dogs were exposed to air at 28.5 degrees C and 95% relative humidity, secretion osmolality became lower, but Na+/Cl- remained unchanged. In four other dogs, secretions approached the osmolality of plasma when inspired air was at 36.4 degrees C and 100% relative humidity. These secretions contained 22% higher Cl- and a lower Na+/Cl- than plasma. The differences between airway secretions and interstitial fluid suggest that secretions are formed by active Cl- transport. In another four dogs, secretion osmolality was higher with mouth breathing than breathing through the nose. Inasmuch as humidified and warmed air lowered and mouth breathing raised the osmolality of airway secretions, we postulate that the hyperosmolality of secretions results from water loss from the airway surface during conditioning of inspired air.

Animals↗
PubMed1979

Human response to controlled levels of inert dust.

We studied nasal mucous flow, airway resistance, and subjective response in 16 young healthy subjects during 5-hour exposures to 2, 10, and 25 mg of inert dust per m3 in an environmental chamber. The dust was a fully polymerized plastic dust containing carbon black. The number of these particles in room air, expressed as a per cent of the total number of particles was 36, 41, 14, 7, and 2, respectively, for the aerodynamic size ranges less than or equal to 1.8, 1.9 to 5.3, 5.4 to 8.9, 9.0 to 12.4, and greater than or equal to 12.5 micron. No significant changes in nasal mucociliary clearance rate or nasal resistance were observed. At all dust concentrations there was a decrease in 1-sec forced expiratory volume, but not in the forced vital capacity or the forced expiratory flow during the middle half of the forced vital capacity. The nasal penetration fraction of particles was approximately 55 per cent for the smallest particles and 20 per cent for the largest particles. Discomfort was proportional to the concentration of dust, but lagged almost 2 hours behind the changes in dust concentration. The discomfort was never excessive; the main complaints were dryness in the nose and pharynx.

Adult↗
PubMed1978

Nasal mucociliary clearance in man.

Nasal mucociliary clearance was measured in healthy young human subjects and tracheal clearance in the experimental animal under a wide variety of conditions. There is a broad range of clearance rates whether at standard ambient conditions (23 degrees C, 50% relative humidity) or in the face of a number of environmental variables. The degree to which those differences are attributable to the effectiveness of ciliary beating or the character of airway secretions is not known. Studies of tracheobronchial secretions simultaneous with clearance measurement in the anaesthetized dog have not yet provided a definite answer. Variations in upper respiratory defence mechanisms may bear some relationship to the aetiology of small airway disease in the lungs.

Adult↗
PubMed1978

Tracheobronchial secretions collected from intact dogs. I. Protein and mucous glycoprotein composition.

Tracheobronchial secretions (TBS) were collected in situ from intact, anesthetized dogs, and the protein composition and distribution were studied. TBS were separated into supernatant and pellet phases by centrifugation. The supernatant phase comprised 85%, by weight, of the secretory mixture; yet it contained only 58% of the total protein. Peptides of apparent molecular weights ranging from 16,000 to 154,000 daltons were present in the supernatant phase. Electrophoretic and immunochemical comparisons with canine serum suggested that certain of the peptides were of plasma origin including albumin, IgG, IgA, and IgM. Albumin and IgG comprised approximately 70% of the supernatant phase protein. Three percent of the total TBS protein was contributed by the peptide portion of mucous glycoproteins (mucins), and 97% of the mucin protein separated into the pellet phase. When compared to mucus collected from a canine tracheal pouch, TBS was less concentrated in mucins, and differences were observed in electrophoretic profiles between the two samples.

Animals↗
PubMed1978

Tracheobronchial secretions collected from intact dogs. II. Effects of cholinomimetic stimulation.

The effect of cholinomimetic stimulation on the quantity and composition of tracheobronchial secretions (TBS) collected from intact dogs was studied. After the administration of methacholine chloride, the collection rate of TBS increased over threefold within 10 min and returned to the control level by 50 min. Even though there was an increase in the total amount of protein collected, the protein concentration of the secretions decreased initially by 40%, returning to normal by 30 min. This was the result of an apparent dilution of the secretions by nonproteinaceous components. In addition, at 10 min, there was an increase in the protein associated with mucins. These responses were blocked by the preadministration of atropine. When TBS was separated into supernatant and pellet phases by centrifugation, we found that, following methacholine, there was a 35% increase in the ratio of albumin to IgG in the supernatant phase. These results suggest that the increased secretion due to methacholine may result, in part, by a selective filtration of fluid from the interstitial and/or vascular compartment(s) with proteins appearing in the secretory mixture based partially on their size.

Animals↗
PubMed1978

Tantalum tracheography in upper airway obstruction: 100 experiences in adults.

A total of 100 tantalum cine laryngotracheograms were performed in adults with documented or suspected upper airway obstruction. With appropriate precautions, tantalum powder proved to be a safe material for delineating tracheal and laryngeal abnormalities. A cine recording to document tracheomalacia as well as a careful evaluation of the larynx are useful extensions of examination of patients with suspected upper airway obstruction. Tracheomalacia was found in 35% of our series; 29% showed laryngeal abnormalities. With modifications to correct for magnification, the tantalum tracheogram gives the surgeon the exact length of trachea to be resected. When tantalum becomes approved by the Food and Drug Administration, we expect that tantalum cine laryngotracheography will be the preferred means for study of upper airway obstruction.

Adult↗
PubMed1977

Human nasal mucosal function at controlled temperatures.

We exposed 16 healthy human volunteers to air temperatures ranging from 7 to 39 degrees C and measured nasal mucus flow, nasal airflow resistance, forced vital capacity, rectal and body surface temperature, and air temperature within the nasal passage. A moderate fall in nasal mucus flow rate in the anterior and middle parts of the nose was observed with temperature above or below 23 degrees C. The nasal airflow resistance decreased in warm air and tended to increase in cold air. No significant changes in forced vital capacities or rectal temperature were observed. Nasopharyngeal end inspiratory air temperatures at 23 degrees C averaged 32.6 degrees C. At environmental temperatures of 15 and 31 degrees C they average 28.1 and 32.8 degrees C, respectively. Although we found alterations in upper airway function associated with altered inspired air temperature, over the range of 32 degrees C studied these changes were of minor physiological significance.

Acclimatization↗
PubMed1977

The upper airways. II. The larynx and trachea.

The laryngotracheal airway is the bottleneck of the respiratory system. Whereas disease in the nose or in the bronchial airways will affect respiratory airflow in a limited way, laryngotracheal disease must always be considered potentially life threatening. The nasal airway is the normal access to the lungs. As such, it serves vital functions in modifying the condition of ambient air before its access to the lungs. Impairment of the efficacy of nasal function in that regard will inevitably cast an unaccustomed burden on the lower airways and may possibly play a role in the long-term development of small airway disease in the lungs. When the nose is bypassed, acutely, as in orotracheal intubation, or chronically, as in tracheostomy or the laryngectomee, the pulmonary airways inevitably suffer. Attempts to substitute for the nose by humidification of inspired air are essential, but our current methods are not free of hazard and are of questionable efficacy. A better understanding of upper airway function and the injury resulting from malfunction or conducting ambient air directly to the trachea is now within our grasp but is not yet fully realized.

Airway Obstruction↗
PubMed1976

Collection of normal canine tracheobronchial secretions.

A technique is described for the collection of tracheobronchial secretions from the upper trachea of anesthetized dogs. The method is simple, relatively quantitative, and provides secretory material in quantity suitable for biochemical or rheological studies. In 42 experiments comprising 184 individual samples we have found the collection rate of tracheobronchial secretions to be 1.0 +/- 0.1 mg/min per kg (mean +/- SEM).

Animals↗