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Biomedical subjects

C H Fanta

Publications and source records attributed to C H Fanta.

32 records · Page 2Linked to original sources
PubMed1983

Maximal shortening of inspiratory muscles: effect of training.

Normal subjects can increase their vital capacity by appropriate training. We tested whether that change can be achieved by greater maximal shortening of the inspiratory muscles without concomitant increases in peak static inspiratory pressures. Sixteen healthy volunteers participated in the study: eight were randomly assigned to make 20 inhalations to total lung capacity, held for 10 s with the glottis open, each day for 6 wk; the remainder served as nontraining controls. Before and after the 6-wk study period, we made multiple determinations of lung volumes and of curves relating lung volume to maximal static inspiratory (and expiratory) pressure. Control subjects had no significant changes from base line in any variable. In the training group, the mean vital capacity increased 200 +/- 74 ml (P less than 0.05) or 3.9 +/- 1.3% (P less than 0.02), without a significant change in residual volume. After training, the mean maximal inspiratory pressure at the airway opening (PI) at a lung volume equal to the base-line total lung capacity was 27 +/- 8 cmH2O in this group (vs. zero before training; P less than 0.02). Values of PI in the mid-vital capacity range did not change. We conclude that in response to appropriate training stimuli inspiratory muscles can contract to shorter minimal lengths, a capacity potentially important in progressive pulmonary hyperinflation.

Adolescent↗
PubMed1982

Leukemic cell lysis pneumonopathy. A complication of treated myeloblastic leukemia.

The course of acute noninfectious pulmonary infiltrates in five patients with myeloblastic leukemia was evaluated. All had circulating blast cells (range, 245-192,000/mm3) and recently had received chemotherapeutic drugs for their leukemia. Within four days of the nadir of their leukocyte counts, a patchy, often multilobar pneumonitis developed. Cultures for bacteria, fungi, and viruses were all negative, and no clinical response was observed to broad-spectrum antibiotics. On lung biopsy, pathologic changes were characterized by diffuse alveolar damage with degenerating blast cells in the interstitium and in organizing alveolar exudates. No potential pathogenic organisms were seen on light or electron microscopy of the biopsy samples. In each case the pulmonary infiltrate resolved without specific therapy. We postulate that lysis of leukemic cells, with subsequent release of their enzyme contents, led to the diffuse alveolar damage observed pathologically. Leukemic cell lysis pneumonopathy may be one of the potential causes of pulmonary infiltrates in leukemic patients and can be distinguished pathologically by its distinctive pattern.

Adult↗
PubMed1982

Emergency room of treatment of asthma. Relationships among therapeutic combinations, severity of obstruction and time course of response.

In an effort to determine the optimal emergency therapy for acute episodes of asthma, we randomly, assigned 102 acute ill patients to 60 minutes of treatment with inhaled isoproterenol alone, isoproterenol plus intravenous aminophylline or isoproterenol plus a single oral dose of an elixir of theophylline. Patients requiring treatment beyond this time were given an injectable sympathomimetic agent in addition. The combination of isoproterenol and a methylxanthine was not found to be better than isoproterenol alone, and the route of administration of methylxanthine was not an important determinant of either the serum theophylline level or the therapeutic response. A major variable that influenced the duration of therapy needed to produce a remission was the severity of the obstruction at presentation. Persons whose initial 1-second forced expiratory volumes were less than 30 percent of predicted and who did not improve 35 percent or more to at least 40 percent of predicted at the end of 60 minutes of intense treatment were those who ultimately required prolonged emergency room therapy and/or hospital admission for control of their symptoms. Thus, simple objective assessment of the degree of impairment at presentation coupled with the response to initial treatment will serve to identify early a high-risk group of asthmatic patients in whom the usual emergency room therapeutic modalities will often prove ineffective.

Adolescent↗
PubMed1982

Inhibition of bronchoconstriction in the guinea pig by a calcium channel blocker, nifedipine.

We investigated the inhibitory effects of nifedipine, a calcium channel blocker, on airway smooth muscle constriction in the guinea pig. In vitro, nifedipine (0.003 to 3.0 microM) caused significant dose-dependent reversal of intrinsically existing tone in both tracheal spirals and parenchymal strips. Nifedipine also inhibited the constriction of tracheal spirals and parenchymal strips induced by two different agonists, histamine and carbachol. At a concentration of 3.0 microM, nifedipine increased by 48-fold the concentration of carbachol required to produce a 50% of maximal contraction of parenchymal strips, and by 5-fold the concentration of histamine. Increasing extracellular calcium ion concentration in the tissue baths significantly diminished the inhibitory action of nifedipine. In vivo, nifedipine (30 micrograms/kg body weight given intravenously) did not alter pulmonary resistance or dynamic compliance. It did, however, attenuate histamine-induced bronchoconstriction in 3 of 5 animals studied. In response to the maximal dose of histamine infused, mean pulmonary resistance rose 40 +/- 16% (SEM) after nifedipine versus 182 +/- 65% in the control animals (p less than 0.025) and mean dynamic compliance decreased 35 +/- 8% after nifedipine versus 58 +/- 6% in the control animals (p less than 0.01). Thus, this calcium channel blocker inhibits mediator-induced constriction of both central and peripheral airway contractile tissues, a finding of potential clinical applicability.

Animals↗
PubMed1981

Effects of cromolyn sodium on the response to respiratory heat loss in normal subjects.

To investigate whether premedication with cromolyn sodium blunts the bronchoconstrictor response that occurs in normal subjects after extreme degrees of airway cooling, we had 9 adult male inhale either cromolyn or placebo on separate days, in a random, double-blind fashion, before challenges with cold air. The latter consisted of eucapnic hyperventilation to levels in excess of 85% of the indirect maximal breathing capacity while the subjects breathed air at -13 degrees C. Partial and maximal expiratory flow-volume curves were measured before and after medication and after hyperventilation. Neither cromolyn nor placebo inhalation per se significantly affected pulmonary function. The cold-air challenges caused significant decreases in expiratory flows, and these changes were significantly attenuated by cromolyn but not placebo. Thus, in normal subjects, cromolyn has the ability to modify the airway response to respiratory tract heat loss. Because the subjects were free of sensitized airway mast cells, we interpret these findings as further evidence that cromolyn sodium has immunologic and nonimmunologic modes of action.

Adult↗
PubMed1981

A controlled trial of the use of single versus combined-drug therapy in the treatment of acute episodes of asthma.

Eighty-nine patients who presented to the hospital for treatment of acute episodes of asthma were randomly assigned to initial therapy with subcutaneously administered epinephrine or 1 of 2 combination regimens consisting of intravenously administered aminophylline and either subcutaneously administered of epinephrine or inhaled isoproterenol. During the first hour of treatment, as a group, the patients treated with the 2-drug regimens showed greater objective improvement than did patients who received epinephrine alone. This was particularly true for patients with either severe airway obstruction or a subtherapeutic theophylline concentration at the time of presentation. There were no differences in the heart rate and blood pressure responses to the 3 regimens, and symptoms consistent with drug side effects were not reported more frequently by patients treated with 2 drugs. Thus, the combination of sympathomimetics and aminophylline appear more effective, and no more toxic, than epinephrine alone for the initial treatment of acute episodes of asthma.

Acute Disease↗
PubMed1981

Differentiation of recurrent pulmonary emboli from chronic obstructive lung disease as a cause of cor pulmonale.

A patient with chronic obstructive pulmonary disease had severe dyspnea and cor pulmonale that were suspected in life and proved at autopsy to be the result of multiple small pulmonary thromboemboli. Radionuclide lung scanning and pulmonary angiography failed to diagnose the extensive peripheral embolization in this setting. The sensitivity and specificity of these diagnostic techniques are discussed, as well as the pulmonary function and gas exchange characteristics that led to the clinical suspicion of recurrent small emboli in this patient.

Autopsy↗
PubMed1980

Emergency therapy of asthma: comparison of the acute effects of parenteral and inhaled sympathomimetics and infused aminophylline.

Forty-eight patients who presented with acute episodes of asthma were randomized to treatment with subcutaneously administered epinephrine, inhaled isoproterenol, or intravenously administered aminophylline. The patients' couses were followed clinically and with spirometry. Although there were no significant differences between the groups before treatment for any measured variable, at the end of 1 hour, the mean improvement inforced expiratory volume in one second (FEV1) was significantly greater for patients treated with epinephrine (0.76 L) or nebulized isoproterenol (0.79 L) than for those given aminophylline (0.23 L). Similarly, the mean duration of therapy required before discharge from the emergency room was significantly longer for patients receiving aminophylline (5.4 h) than for patients treated with either epinephrine (3.5 h) or isisoproeternol (3.0 h). There was no significant differences between the effects of the 2 beta agonists. These results demonstrated that short-acting sympathomimtic agents produce more rapid and potent bronchodilatation in acutely ill asthmatics than that provided by intravenously administered methylxanthines, and that there are no disadvantages to using an inhaled beta agonist rather than one administered parenterally.

Administration, Intranasal↗
PubMed1980

A reassessment of the effects of oropharyngeal anesthesia in exercise-induced asthma.

To investigate the possibility that stimulation of neural receptors in the posterior pharynx plays a role in the pathogenesis of exercise-induced asthma, we had 10 asthmatic subjects simulate the hyperpnea of exercise by performing eucapnic hypervenilation in the presence and absence of oropharyngeal anesthesia induced by lidocaine. During these studies, the amount of ventilation and temperature and water content of the inspired air were rigorously controlled in order to keep respiratory heat loss constant for each trial. Multiple aspects of pulmonary mechanics were measured before and after the pharynx was sprayed with either water or lidocaine, as well as after the completion of the bronchial challenge. Neither agent, in and of itself, produced alterations in lung function at rest. Eucapnic hyperventilaltion was followed by a significant reduction in pulmonary mechanics in both situations, and there were no significant differences between the effects of lidocaine or water. Thus, we were unable to find any evidence for the existence of "irritant-like" receptors essential to the pathogenetic consequences of airway cooling in the posterior pharynx.

Adult↗
PubMed1980

Pseudopseudotumor of the lung. Hepatic herniation into the right major fissure imitating a pseudotumor on chest roentgenogram.

A young man presented to us with an asymptomatic ovoid mass which appeared to be in the right major fissure. The roentgenographic appearance of the lesion was that of a pseudotumor. The computerized tomography scan suggested tissue density leading to exploration. At surgery, we found the mass to be a portion of liver herniated through a diaphragmatic defect. Thus, we add type 2 hepatic herniation to congestive heart failure, empyema, hemothorax, postinflammatory "fibromas" and malignancies as a cause of interlobar pleural densities.

Adult↗