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Biomedical subjects

R M Rogers

Publications and source records attributed to R M Rogers.

At least 109 records · Page 6Linked to original sources
PubMed1979

A noninvasive technique for measurement of changes in specific airway resistance.

A simple noninvasive technique for measuring specific airway resistance (airway resistance X thoracic gas volume) in unanesthetized guinea pigs is described. Specific airway resistances measured by this technique correlated well (r = 0.81) with the resistances obtained using a pleural catheter pressure measurement over a wide range of airway resistances. This range of resistances was generated by exposing the pigs to an aerosolized histamine bronchial challenge. The average specific airways resistance in unchallenged pigs was 1.24 +/- 3.47 cmH2O/s, somewhat lower than found by others, probably reflecting in part our larger pigs and in part some uncertainty in the absolute value of resistance inherent in our measurement technique. This technique is particularly useful in bronchial challenge experiments because of its sensitivity to acute changes in airway resistance.

Airway Resistance↗
PubMed1979

Hypersomnolent and nonhypersomnolent patients with upper airway obstruction during sleep.

When the syndrome consisting of sleep-induced apnea and hypersomnolence is due to upper airway obstruction, the hypersomnolence is believed to be the direct result of deprivation of sleep related to such obstructions. The purpose of this report is to describe a group of four asymptomatic subjects with upper airway obstruction during sleep. These subjects were matched with a group of patients with the syndrome of sleep-induced apnea and hypersomnolence. There were no significant differences between symptomatic and asymptomatic groups in terms of the absolute number of upper airway obstructions (252 vs 231), their mean duration (20.8 vs 25.9 seconds), the mean arterial carbon dioxide tension during sleep (39 vs 39 mm Hg), or the electroencephalographic patterns during sleep. The only variables that emerged as significantly different between the two groups were the weights (128 vs 90 kg; P less than 0.05), the low arterial oxygen pressure (PaO2) on waking (54 vs 80 mm Hg; P less than 0.002), and the lower PaO2 during sleep (47 vs 70 mm Hg; P less than 0.01) in the symptomatic patients. From these data, we conclude that the hypersomnolence in patients with sleep-induced apnea due to upper airway obstruction cannot be explained by deprivation of sleep, and other factors need to be carefully examined in future studies.

Adult↗
PubMed1978

PUlmonary alveolar proteinosis: shunt fraction and lactic acid dehydrogenase concentration as aids to diagnosis.

The shunt fraction breathing 100 per cent O2 and serum lactic acid dehydrogenase concentration were evaluated as 2 easily obtainable, rapid laboratory procedures that might aid in the early diagnosis of pulmonary alveolar proteinosis. The mean +/- SE shunt fraction was 20 +/- 1.2 per cent in patients with alveolar proteinosis compared to 8.9 +/- 0.5 per cent in other groups of patients with diffuse lung disease (P less than 0.001). The lactic acid dehydrogenase concentration was increased in all patients with alveolar proteinosis and helped to separate further the 2 groups. Thus, when a patient presents with the findings of chronic diffuse lung disease, the lactic acid dehydrogenase concentration and the shunt fraction can be of value in suggesting the diagnosis of pulmonary alveolar proteinosis.

Biopsy↗
PubMed1978

Physiologic effects of bronchopulmonary lavage in alveolar proteinosis.

The clinical and physiologic effects of bronchopulmonary lavage of both lungs at separate times in 14 patients with alveolar proteinosis proved by biopsy were followed for 2 to 96 months. Before lavage, all patients had moderate to severe dyspnea on exertion. Twelve had a nonproductive cough, and 2 had a productive cough; both were smokers. Nine had generalized fatigue, and 4 had weight loss. Twelve of 14 had fine inspiratory rales. All of the patients had abnormal chest roentgenograms, and 13 of 14 had an increased lactate dehydrogenase concentration. After lavage, all patients had loss of fatigue and improved exercise tolerance, with most returning to normal activity. Cough cleared in 12 of 14 and remained only in the cigarette smokers. Inspiratory rales cleared completely in most patients (11 of 12) and partially in one. The rales usually returned during exacerbations. Physiologic measurements that changed significantly after bilateral lavage included: vital capacity, total lung capacity, resting room air PO2, exercise PO2, PO2 while breathing 100 per cent O2, and DLCO. Because all measurements were made within 5 days of the second lavage, one must attribute the acute improvement to the removal of proteinaceous material from the alveoli. The long-term effects varied; some patients required annual or semiannual lavages, wherease others remained in remission after lavage for 36 to 96 months. Exacerbations were accompanied by increased dyspnea, reappearance of rales, and deterioration of the gas-exchange parameters noted previously. Repeat lavage reversed the clinical symptoms and physiologic abnormalities in patients who had recurrences.

Adult↗
PubMed1977

Retrognathia and sleep apnea. A life-threatening condition masquerading as narcolepsy.

The association of sleep apnea with daytime hypersomnolence without obesity, and its potentially lethal cardiopulmonary sequelae, make it crucial that this condition be distinguished from narcolepsy. A patient with retrognathia who had been diagnosed as a narcoleptic for 15 years had the primary complaint of excessive daytime sleepiness. Sleep laboratory evaluation showed severe hypoxemia and a mean of 366 upper airway obstructions per night. The patient was treated with a tracheotomy; this resulted in relief of the sleep-related upper airway obstructions, hypoxemia, and hypersomnolence.

Airway Obstruction↗
PubMed1977

Aerosol administration of fenoterol hydrobromide (Th 1165a) in subjects with reversible obstructive airway disease.

Bronchodilatory and side effects of fenoterol hydrobromide (Th1165a; hydroxyphenylorciprenaline; Berotec) and isoproterenol given by inhalation were compared in a double-blind crossover study involving 20 volunteer subjects with reversible obstructive disease of the airways. Subjects inhaled medications from aerosol canisters containing fenoterol hydrobromide (0.1 mg, 0.2 mg, or 0.4 mg) or isoproterenol (0.15 mg) or an inert placebo propellant in a random sequence of five testing days. All active drugs substantially increased the forced expiratory volume in one second, the mean forced expiratory flow during the middle half of the forced vital capacity, and the specific conductance. The onset of bronchodilation after both fenoterol and isoproterenol was rapid, but the effect from fenoterol lasted much longer, up to eight hours. None of the medications cuased significant tachycardia or hypertension. After inhalation of 0.1 mg of fenoterol hydrobromide, none of the subjects reported nervousness, headache, tremor, or nausea, incontrast with results reported for isoproterenol, higher aerosol doses fo fenoterol, or oral administration of fenoterol. No additional therapeutic benefit was found in the administration of higher doses of fenoterol.

Adolescent↗
PubMed1976

Enhancement of bactericidal capacity of alveolar macrophages by human alveolar lining material.

In vivo studies have shown a major role for the alveolar macrophage in the killing of inhaled bacteria. This contrasted with earlier work which showed a preservation of phagocytic properties but a loss of bactericidal capacity when alveolar macrophages were studied in vitro. Recently, alveolar lining material (ALM) from rats has been shown to enhance the in vitro bactericidal capacity of alveolar macrophages from homologous animals against Staphylococcus aureus. Utilizing a similar system, we have confirmed that rat alveolar macrophages do not kill S. aureus in vitro unless the bacteria have been incubated with rat ALM (R-ALM) before phagocytosis. In addition, human ALM (H-ALM) from 7 of 11 patients assayed showed an enhancement of bactericidal capacity by rat alveolar macrophages which was not significantly different from the results utilizing R-ALM. H-ALM from the other four patients gave results which differed significantly from results with H-ALM from the first seven patients and R-ALM (P less than 0.001). Preliminary results suggest that the factor enhancing the bactericidal capacity of rat alveolar macrophages is present in the lipid fraction of the ALM. Further characterization of the ALM is warranted in an effort to explain the enhancement of the bactericidal capacity of alveolar macrophages by most, but not all, H-ALM tested.

Animals↗