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Biomedical subjects

R Dougherty

Publications and source records attributed to R Dougherty.

26 records · Page 2Linked to original sources
PubMed1977

A new roentgenographic method for estimating mucous velocity in airways.

A new roentgenographic method is described for the estimation of mucous velocity in airways. Radiopaque discs of teflon mixed with bismuth trioxide were deposited in the trachea, and their motion was observed by a fluoroscopic image intensifier. Simultaneous measurements of disc movement were obtained by a previously reported cinebronchofiberscopic method and by the roentgenographic method in 6 anesthetized dogs. Mean +/- SD tracheal mucous velocity was 8.5 +/- 7.3 mm per min by the roentgenographic method, and 7.6 +/- 7.1 mm per min by the cinebronchofiberscopic method. Discrepancies between the 2 methods for individual disc velocities could be accounted for by the cumulative errors of both methods. The roentgenographic method was also used in 7 normal volunteers who did not have topical anesthesia of the tracheobronchial tree. The discs were blown through the inner channel of a bronchofiberscope, the tip of which was located just above the vocal cords. Placement of the discs on the tracheal mucosa generally did not produce coughing. Tracheal mucous velocity ranged from 7.4 to 19.4 mm per min as estimated from videotape recordings of the image intensifier images. There was no consistent difference in velocity between the erect or supine position, or after topical anesthesia with lidocaine.

Adult↗
PubMed1977

Acute effects of an aerosol hair spray on tracheal mucociliary transport.

The acute effects of a commercially available aerosol hair spray preparation and a Freon propellant on various pulmonary function tests and tracheal mucociliary transport were studied in 12 normal nonsmokers. Tracheal mucous velocity was estimated by a roentgenographic method. In 7 subjects exposed to hair spray by directing the aerosol to the hair for 20 sec, no significant changes occurred in any of the various pulmonary function parameters, whereas mean tracheal mucous velocity decreased by 57 per cent (P less than 0.001) 1 hour after exposure. This effect was transient and could no longer be demonstrated after 3 hours. No significant changes in tracheal mucous velocity or pulmonary function tests were observed in the 5 control subjects exposed to the Freon propellant alone. These observations suggest that acute exposure to aerosol hair spray produces a transient impairment of a pulmonary defense mechanism, and that measurements of mucociliary transport is a more sensitive indicator of this type of airway irritation than conventional pulmonary function tests.

Adult↗
PubMed1976

Effects of water immersion to the neck on pulmonary circulation and tissue volume in man.

Utilizing the rebreathing of a gas mixture containing C2H2, C180, He O2, and N2, we obtained serial measurements of the pulmonary capillary blood flow (Qc), diffusing capacity per unit of alveolar volume (DL/VA), functional residual capacity (FRC), pulmonary tissue plus capillary blood volume (VTPC), and O2 comsumption (VO2) in five normal subjects under the following conditions: 1) 6 h of sitting, 2) 4 h of sitting while immersed in thermoneutral water to the neck, and 3) 4 h of lying in thermoneutral water to the neck. Water immersion (NI) was preceded and followed by 1-h prestudy and 1-h recovery periods. The measurements were made at 30-min intervals. Seated NI produced a fourfold increase in sodium excretion (UNaV), a 25-36% increase in Qc, a 45-59% increase in DL/VA, and a 30-36% decrease in FRC. This occurred as early as the 1st h of NI and persisted throughout the 4-h period of study. Throughout the seated control and NI periods, VO2, heart rate, and VTPC remained constant. During supine NI, Qc, HR, DL/VA, FRC, and VO2 did not differ significantly from supine prestudy. These date demonstrate that seated NI causes a significant increase of Qc and DL/VA which persists throughout the immersion period. Furthermore, the lack of change of VTPC suggests that the central vascular engorgement induced by seated NI is not accompanied by extravasation of fluid into the pulmonary interstitial space.

Adolescent↗
PubMed1976

Effect of sequential anti-G suit inflation on pulmonary capillary blood flow in man.

The hemodynamic effects of an anti-G suit, sequentially filled from below upward (M-aG), were compared to those of the standard USAF anti-G suit (S-aG) in 10 men supine and under +1 Gz stress produced by 90 degrees head up passive tilt. S-aG was found to fill from the abdominal bladder downward. The heart rate and the pulmonary capillary blood flow (Qc), as estimated by a nitrous oxide plethysmographic method, were used as criteria of effectiveness. Heart rate did not vary between the suits during the supine and upright studies. In the supine position, the first M-aG inflation induced a significant increase of Qc, 2.5 1 min above the Qc of the S-aG inflation. After 90 degrees head up tilt, M-aG inflation as associated with a significant increase of Qc, 1.7 1 min greater than the Qc produced by S-aG inflation. Since leg bladder inflation may play a critical role in high-G tolerance, the sequential filling from below upward of the anti-G suit may further increase the G protection compared to the standard garment. In addition, the modified anti-G suit may be a useful device for treatment of circulatory shock and postural hypotension when the venous return is decreased.

Acceleration↗
PubMedDate not supplied

Effect of a diet low in saturated fatty acids on plasma lipids, lipoproteins, and HDL subfractions.

The effect on serum high density lipoprotein subfractions of a low fat diet with a high ratio of polyunsaturated-to-saturated fatty acids was studied in 38 middle-aged volunteers (19 men and 19 women) in North Karelia, Finland. The mean serum HDL2 cholesterol decreased from 32 +/- 2 mg/dl (mean +/- SE) to 28 +/- 2 mg/dl (p less than 0.001) during the experimental diet and returned to 33 +/- 2 mg/dl (p less than 0.001) after a return to the original diet. No changes were observed in the concentration of HDL3 cholesterol. A highly significant decrease was observed in serum apoprotein A-I concentration, but not in apoprotein A-II concentration during the experimental diet. It is concluded that a low-fat, high-P/S ratio diet lowers LDL and HDL2 cholesterol in healthy volunteers, but does not influence the level of HDL3 subfraction.

Apoproteins↗