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Biomedical subjects

J W Jenne

Publications and source records attributed to J W Jenne.

At least 37 records · Page 2Linked to original sources
PubMed1984

The effect of maintenance theophylline therapy on lung work in severe chronic obstructive pulmonary disease while standing and walking.

There is controversy whether routine use of theophylline is warranted in chronic obstructive pulmonary disease (COPD). Effects on spirometry are minimal, and subjective relief is difficult to document. Therefore, we undertook to study the pulmonary effects of theophyline using a functional approach, namely, its effects on the lung mechanics of a standing or walking patient. In a double blind, placebo controlled crossover study, 400 mg of slow-release theophylline (TheoDur) were given twice a day in 13 trials to 10 patients with severe COPD. Lung mechanics were calculated on a breath-by-breath basis by a pulmonary mechanics computer from esophageal pressures and flow. Expired volumes were simultaneously collected. Spirometry was then performed. On the placebo limb, the spirometric response to 0.5 mg terbutaline given subcutaneously was compared with the theophylline response. At a mean serum theophylline level of 12.3 micrograms/ml, theophylline produced in the entire group a mean reduction in the work of breathing done on the lung (WL) of 16% (p less than 0.002) while walking, but a significant effect while standing was not detected. During both walking and standing, the mean reduction in lung resistance (RL) was 15 to 16% (p less than 0.002). Minute volume (VE) was increased at borderline significance, with a mean reduction while walking of 19% in the ratio of WL to VE (p less than 0.002). In the individual patient, changes in WL were influenced more by changes in VE than by changes in RL; in fact, changes in WL correlated best with changes in the product of (VE)2 and RL. Theophylline produced a mean increase of 15% in forced expiratory volume in one second (FEV1) and 16% in forced vital capacity (FVC).(ABSTRACT TRUNCATED AT 250 WORDS)

Forced Expiratory Volume↗
PubMed1984

Theophylline use in asthma. Some current issues.

This article summarizes the current use of theophylline and lays a simple pharmacokinetic background for understanding its safe use. Dosing practices that will minimize side effects and toxicity are stressed, along with their management if they do occur. Finally, some currently debated issues over optimal theophylline use are addressed.

Adenosine↗
PubMed1982

Objective and subjective tremor responses to oral beta 2 agents on first exposure. A comparison of metaproterenol and terbutaline.

Objective and subjective postural tremor responses at 60 and 120 min after drug treatment were studied in 24 veterans with chronic obstructive pulmonary disease who received either 5 mg terbutaline, 20 mg metaproterenol, or a placebo in random order. Subjects were fasting, and had not taken theophylline for 15 to 24 h or any oral sympathomimetics for 2 wk. The mean tremor response to terbutaline and metaproterenol was equal at 60 min, but the 120-min response to metaproterenol was less. When the 60- and 120-min responses were averaged, tremor response to terbutaline was significantly greater than that to metaproterenol in a 5 : 4 ratio. Subjective awareness was also greater. These results are consistent with the difference in bronchodilatory potency of the two preparations. That the drug producing the greater tremor could usually be identified by the patient, even at low tremor intensities, is consistent with the hypothesis that perception of tremor is a function of relative rather than absolute increase over basal tremor unless the tremor becomes physically disabling. In general, the individual tremor response was proportional to the extent by which a patient's basal tremor exceeded the minimal basal tremor for the group as a whole. These results fit a model in which the postural tremor derives from beta-sensitive and beta-insensitive cardioballistic and skeletal muscle forces. Variability in tremor response resides principally at the peripheral skeletal beta 2-receptor and its control system.

Administration, Oral↗
PubMed1980

Tachyphylaxis to inhaled isoproterenol and the effect of methylprednisolone in dogs.

Acute tachyphylaxis can be induced to inhaled isoproterenol (ISO) in anesthetized, closed-chested mongrel dogs. The responsiveness to ISO measured as the percent reduction in methacholine-induced bronchoconstriction was decreased significantly (p less than 0.01) after a 1-hr period of repeated ISO inhalations (ISO-loading). Intravenous administration of methylprednisolone (1 mg/kg) reversed the decrease in responsiveness to ISO.

Animals↗
PubMed1977

Subsensitivity of beta responses during therapy with a long-acting beta-2 preparation.

The question whether some tolerance or subsensitivity of various beta receptors develops during therapy with long-acting oral beta-2 agents has practical and theoretical importance. We applied a strong beta-2 stimulus (terbutaline, 5.0 mg orally) at weekly intervals for up to three weeks in 19 stable asthmatics and bronchitics while commencing 5.0 mg terbutaline three times daily. The evening dose was omitted before each morning challenge. Challenges were continued at one and two weeks off terbutaline in some patients to test return of beta function. Patients received no ephedrine for two weeks before the study but were allowed aminophylline or isoproterenol inhalations up to 18 and 4 hr before challenges, respectively. Pulmonary function, pulse, and blood pressure were monitored at 0, 60, 120, and 180 min, and metabolic parameters measured at 0 and 180 min. There was significant drug tolerance in the drop and minimum diastolic pressure reached, rise in lactate, cyclic AMP, and blood glucose, and drop in eosinophils. Peak FEV1 and V50 dropped slightly, but vital capacity and minimal airway resistance did not change significantly. During continuous therapy this slight bronchial subsensitivity is probably obscured by elevated baseline function. It might assume importance during periods of excessive inhaler use or abrupt drug withdrawal.

Asthma↗
PubMed1977

Comparative bronchodilator responses to atropine and terbutaline in asthma and chronic bronchitis.

We have compared bronchodilator responses to atropine and terbutaline in 39 chronic bronchitics and 16 stable asthmatics. Fasting subjects were given either 1.05 mg atropine of 5.0 mg terbutaline orally. Pulmonary function was assessed using the peak responses, namely: three 60-minute intervals for terbutaline and three 30-minute intervals for atropine. A subgroup of five reactive bronchitis patients was given a placebo with no response. Areas under the percent response-time interval curve were compared. Both patient groups responded to the same degree to atropine and terbutaline with respect to reduction of airway resistance. However, the FEV1 and V50 responses to terbutaline were markedly enhanced compared to atropine in the asthmatics while equal to the atropine response in the bronchitis patients. Thus, atropine appears to exert its effect upon both large and small airways in bronchitis, but predominantly on large airways in asthma. The results are consistent with a state of enhanced vagal tone in small airways in bronchitis compared to asthma, but other explanations are conceivable.

Airway Resistance↗
PubMed1977

Apparent theophylline half-life fluctuations during treatment of acute left ventricular failure.

The administration of theophylline in a 63-year-old man with arteriosclerotic heart disease and chronic bronchitis is discussed to illustrate the pharmacokinetics of theophylline in an abnormal host state. The case demonstrates that clearly acute congestive heart failure and its treatment may dramatically affect the kinetics of theophylline elimination. Possible explanations for this phenomenon are presented, and the therapeutic implications are discussed.

Administration, Oral↗