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Biomedical subjects

M R Littner

Publications and source records attributed to M R Littner.

35 records · Page 2Linked to original sources
PubMed1982

Lymphocyte beta-adrenergic refractoriness induced by theophylline or metaproterenol in healthy and asthmatic subjects.

Beta-adrenergic refractoriness was assessed in human lymphocytes following in vivo administration of the beta-adrenergic agonist, metaproterenol, the phosphodiesterase inhibitor, theophylline, or both concomitantly, to normal and asthmatic subjects. In normal subjects both beta-adrenergic receptor number and isoproterenol stimulated cAMP response decreases during therapy with metaproterenol (59 +/- 3; 51 +/- 16% of control, respectively), theophylline (76 +/- 6; 78 +/- 16), or concomitant metaproterenol and theophylline (47 +/- 4; 69 +/- 13). The asthmatic subjects were of two types; one type responding to metaproterenol or theophylline therapy by down regulation of receptor number to zero or near zero values, and a second group of asthmatics insensitive to down regulation of receptor number. The results suggest that the induction of the refractory state is different between asthmatics and non-asthmatics, and that there may be a role for cAMP in the development of beta-adrenergic refractoriness, in vivo.

Asthma↗
PubMed1982

Selective subsensitization of beta-adrenergic receptors in central airways of asthmatics and normal subjects during long-term therapy with inhaled salbutamol.

In five subjects with mild asthma and in five normal subjects, we determined the effect of a 4 wk course of inhaled salbutamol (albuterol), 200 micrograms q.i.d., on (1) acute bronchodilator responsiveness, (2) bronchial sensitivity to inhaled histamine, (3) beta-adrenergic protection against histamine-induced bronchospasm, and (4) beta-receptor density of peripheral blood lymphocytes. We observed a diminution in central airway bronchodilator responsiveness (as measured by airway conductance responses) to acutely inhaled salbutamol and to subcutaneous terbutaline in both groups of subjects, although only the response to subcutaneous terbutaline was statistically significant (p less than 0.02). On the other hand, no impairment of small airway bronchodilator responsiveness was noted in either group of subjects when responses were measured as partial expiratory flow rates at 60% below total lung capacity. These findings suggest the development of selective subsensitization of beta-receptors in the larger central airways, where a proportionately greater amount of the inhaled beta-agonist aerosol would necessarily be deposited. A greater loss of protection against histamine-induced bronchospasm was seen in asthmatics than in normals (approximately twofold), although the difference was not significant. A modest but not significant reduction in peripheral blood lymphocyte beta-receptor density was observed by the end of the 4 wk treatment period. The possibility that the observed changes in bronchodilator responsiveness might influence the morbidity and mortality associated with bronchial asthma is discussed.

Administration, Intranasal↗
PubMed1982

The effects of arachidonic acid, PGI2, and 6-keto-PGF1 alpha on cyclic nucleotide concentrations in a ventilated and artificially perfused isolated dog lung.

In 35 isolated dog lung preparations, the pulmonary circulation of the right lung was completely separated from that of the left so that 1 lung of each preparation could serve as a control. The lungs were ventilated with 14% O2, 6% CO2 and 80% N2 and the pulmonary circulations were perfused with a dextran-salt-bicarbonate solution containing theophylline. Samples of perfusate were assayed for cyclic AMP and cyclic GMP (radioimmunoassay). Infusions of arachidonic acid (n=6) and PGI2 (n=4) but not 6-keto-PGF1 alpha (n=3) into the pulmonary circulation led to increases in cyclic AMP compared to control. Cyclic GMP levels were unchanged by the various infusions. Indomethacin (n=4) and acetylsalicylic acid (n=4) (prostaglandin (PG) synthesis inhibitors), and tranylcypromine (n=4) (a PGI2 synthetase inhibitor), prevented the cyclic AMP increases from arachidonic acid. This prevention was not the result of interference with the ability of cells to produce or release cyclic AMP since indomethacin (n=3), acetylsalicylic acid (n=3), and tranylcypromine (n=4) did not prevent cyclic AMP increases from PGI2. We conclude that infusion of arachidonic acid into the canine lung elevated pulmonary cyclic AMP but not cyclic GMP; that part or all of this increase most likely resulted from conversion of arachidonic acid to products of PG synthesis, particularly PGI2; that infusion of PGI2 mimicked arachidonic acid in that pulmonary cyclic AMP but not cyclic GMP was elevated, and that 6-keto-PGF1 alpha, a metabolite of PGI2, is unlikely to account for the cyclic AMP increases in this study.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Respiratory patterns associated with hemoglobin desaturation during sleep in chronic obstructive pulmonary disease.

Respiration during sleep was monitored in ten patients with chronic obstructive pulmonary disease (COPD) and related to measures of hemoglobin saturation and intrathoracic pressure (ITP) or abdominal wall movement. Seven of the ten patients showed episodic hemoglobin desaturation of at least 5 percent during sleep. Two distinct patient groups could be distinguished on the basis of ITP measurements and breathing patterns. Desaturation was associated with reduced negative ITP or respiratory movement in three patients and with increased negative ITP or respiratory movement in four patients. These data suggest that desaturation may result from at least two distinct mechanisms, involving reduced respiratory effort in one group and increased upper airway occlusion in the other. Desaturation associated with reduced respiratory effort was primarily REM-sleep related and consisted of a few sustained episodes. Desaturation episodes associated with upper airway occlusion occurred in all stages of sleep and were very frequent and of short duration.

Airway Obstruction↗
PubMed1981

Bronchospasm during excretory urography: lack of specificity for the methylglucamine cation.

UNLABELLED: Pulmonary function (specifically, forced expiratory volume in 1 sec and forced expiratory flow at low lung volumes) was measured with maximal expiratory flow-volume curves during excretory urography in 70 patients and during sham procedures in 27 subjects. Forty-one patients received a 100 ml intravenous bolus of 60% methylglucamine diatrizoate and 29 patients received 100 ml of 50% sodium diatrizoate. Within 20 min, greater than 95% of patients had bronchospasm as indicated by asymptomatic decreases in pulmonary function. These decreases were significantly (p less than 0.001) greater than in the subjects undergoing sham procedures. Greater than 50% of patients had a maximum decrease in pulmonary function that exceeded the range of variability for consecutive repetitions of maximal expiratory flow-volume curves. These patients were classified as responders during excretory urography. The prevalence of responders was similar in methylglucamine diatrizoate and sodium diatrizoate patients. The magnitude of maximum decreases in pulmonary function did not differ significantly between methylglucamine diatrizoate and sodium diatrizoate responders. CONCLUSIONS: Sodium diatrizoate does not offer an advantage over methylglucamine diatrizoate with respect to asymptomatic bronchospasm during excretory urography.

Adolescent↗
PubMed1980

Monitoring of oxygen delivery systems in clinical practice.

The measurement of hypopharyngeal FIO2, is a simple and rapid method for evaluating oxygen delivery systems in clinical practice. Hypopharyngeal FIO2 measurements were compared to other established methods of inspired gas measurement, namely, tracheal gas sampling and exhaled gas analysis. Hypopharyngeal sampling and exhaled gas analysis. Hypopharyngeal sampling compared favourably with these methods. Furthermore, arterial blood gas samples from patients receiving oxygen by aerosol mask correlated with the hypopharyngeal measurements but not with the delivery system's settings. In normal, healthy subjects, the authors studied variables known to influence FIO2. Using nasal prongs as well as an aerosol mask system, the authors studied the interaction of the wall flow rates, the concentration (Venturi) settings (in the case of the aerosol mask), and the subject's respiratory rate. Under these controlled conditions of tidal breathing, the hypopharyngeal FIO2 was directly related to the total flow of gas from the delivery system and the concentration of the Venturi setting but inversely related to the respiratory rate. Hypopharyngeal gas sampling offers a simple method for evaluating and correcting a patient's inspired oxygen concentration.

Humans↗
PubMed1980

Determinants of oxygen desaturation in the course of ventilation during sleep in chronic obstructive pulmonary disease.

During sleep, none of 9 subjects with chronic obstructive pulmonary disease (COPD) were apneic. Despite ventilation, acute arterial oxygen desaturation of 11% or more occurred in 6 of them. The other 3 were nondesaturators (i.e., 3% or less desaturation) during sleep. The desaturation that occurred in the 6 subjects with COPD was associated with episodes of (1) esophageal pressure or abdominal respiratory movement that acutely decreased in amplitude during rapid-eye-movement (REM) sleep, or (2) esophageal pressure or abdominal respiratory movement that acutely increased in amplitude in association with snoring during non-REM and REM sleep. During daytime wakefulness, ventilatory responses to hypoxia and hypercapnia were markedly less in the 6 desaturators compared with the 3 nondesaturators and 5 healthy control subjects. The decreased ventilatory responses in the 6 desaturators appeared to result from both impaired respiratory mechanical effectiveness and impaired respiratory center responsiveness to chemoreceptor stimulation. We suggest that subjects with COPD with these respiratory impairments are predisposed to develop severe nonapneic oxygen desaturation during the added respiratory impairment of REM sleep or of what appears to be sleep-related partial upper airway obstruction.

Chronic Disease↗
PubMed1979

Modification of induced airway constriction in healthy subjects.

Unlike asthmatics, healthy persons are relatively unresponsive to airway constrictors. By using partial expiratory flow-volume (PEFV) curves the authors have demontrated, in healthy subjects, dose-related decreases in flow rates following challenge with histamine and methacholine aerosols. With the use of semilogarithmic dose-response curves they have shown that 80 mg oral propranolol augmented, whereas oral pretreatment with 400 mg W10294A (an experimental bronchodilator) decreased, histamine and methacholine-induced airway constriction. However, 300 mg of orally administered aminophylline failed to modify the airway constrictor effects of histamine and methacholine. Moreover, variation was noted in induced airway constriction in healthy subjects with decreases in flow rates being greater in the morning than in the afternoon. The authors conclude that (1) propranolol augments whereas theophylline fails to prevent nonspecific induced airway constriction in healthy subjects. This suggests that the bronchodilator action of theophylline may be unrelated to its phosphodiesterase inhibitory activity, (2) control of volume history, by use of partial expiratory flow-volume curves, is useful in quantifying pharmacologic protection and augmentation of nonspecific induced airway constriction in healthy subjects and (3) conclusions resulting from observations of induced airway constriction in healthy subjects may be dependent upon the effects of diurnal variation.

Adult↗
PubMed1977

The clinical assessment of roentgenographically atypical pulmonary sarcoidosis.

We studied 89 patients in whom the clinical diagnosis of sarcoidosis was supported by the findings on tissue biopsy. A chest roentgenogram in 14 of the patients showed one of the following atypical features: large pulmonary nodules, an alveolar parenchymal pattern or a pleural effusion. Diagnoses of infection, malignancy or vasculitis were suggested by interpretations of atypical chest roentgenograms in eight of these 14 patients. Nonspecific and misleading clinical information contributed. The diagnosis of sarcoidosis was corroborated by extrathoracic tissue biopsies in 11 of the 14 patients. Over an average observation period of 38 months, the 14 patients remained classified as having sarcoidosis. This suggests that an extrathoracic tissue biopsy, whose findings are consistent with sarcoidosis, is often sufficient to support a clinical diagnosis of some forms of roentgenographically atypical pulmonary sarcoidosis.

Adrenal Cortex Hormones↗
PubMed1977

Computerized tomography in pulmonary sarcoidosis.

Six patients with documented pulmonary sarcoidosis were selectively studied with the ACTA scanner. The CT scans were correlated with the standard chest radiographs of these patients. CT scans readily confirmed adenopathy, calcification, and pleural disease. Likewise, diffuse and isolated parenchymal disease was detected and in some cases unexpected lung involvement was noted.

Adult↗
PubMed1977

Evaluation of bronchospasm during excretory urography.

Mean pulmonary function was significantly decreased in 57 patients during excretory urography. Patients with a history of allergy had significantly greater mean decreases in flow rates than those without. Twelve did not have significant decreases in pulmonary function after needle puncture and intravenous injection of 5% dextrose in water. Eight healthy subjects did not have significant mean decreases after intravenous injection of 5% saline. Most patients undergoing excretory urography have bronchospasm that is greater in magnitude in those with a history of allergy.

Adolescent↗
PubMed1977

Assessment of therapy of upper airway obstruction.

Five patients with fixed upper airway obstruction were evaluated with maximum expiratory and inspiratory flow-volume curves before and after surgical repair of the obstruction. Flow-volume curves improved notably in two patients, improved moderately in two, and deteriorated in one. Symptoms and direct visualization of the obstruction before and after surgery correlated well with the changes seen in the flow-volume curves. None of the peak expiratory flow rates returned to predicted values after surgery, indicating at least some residual obstruction in all patients. It is concluded that flow-volume curves are an accurate, noninvasive technique for the diagnosis and subsequent assessment of therapy in patients with fixed upper airway obstruction.

Adult↗
PubMed1977

Severe sarcoidosis in pregnancy.

A case of pulmonary sarcoidosis in a pregnant woman with severe constitutional symptoms and markedly restricted pulmonary function is presented. Serial pulmonary function testing before and during steroid therapy documented significant improvement. Although the severity of this patient's disease is apparently rare, more studies are required to define the prevalence of significant pulmonary function impairment in pregnant women with sarcoidosis.

Adult↗