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Biomedical subjects

M T Newhouse

Publications and source records attributed to M T Newhouse.

At least 19 recordsLinked to original sources
PubMed1992

Ciliary function, cell viability, and in vitro effect of ribavirin on nasal epithelial cells in acute rhinorrhea.

Nasal epithelial (NE) cells were collected from the nasopharynx of 25 individuals with symptomatic colds and 27 healthy volunteers (controls), and ciliary beat frequency (CBF) was assessed by microscopy employing video motion analysis techniques. Baseline CBF was statistically significantly elevated in the group with colds compared to the control group (14.6 +/- 1.5 Hz [mean +/- SD] vs 13.8 +/- 0.9 Hz; p = 0.02). After four days of incubation in culture, there was a significant decrease in the CBF in both groups, with a change from baseline of 1.9 Hz for the cold group, compared to 1.0 Hz for the control group (p = 0.0001). The in vitro addition of ribavirin at 500 micrograms/ml to NE cells from individuals with colds preserved the viability of the cells and maintained the CBF at baseline values. Twenty-four (96 percent) of 25 ribavirin-treated specimens from the cold group survived for four days in culture, compared with 17 (68 percent) of 25 untreated cold specimens. In addition, the ribavirin-treated cells had a mean CBF of 14.2 +/- 1.3 Hz, compared with 12.7 +/- 1.9 Hz for the untreated cell samples (p = 0.0005). Ribavirin had no effect on NE cells from the control group. These results suggest that ribavirin in a concentration of 500 micrograms/ml may have some benefit in the treatment of acute rhinorrhea.

Acute Disease↗
PubMed1991

Mechanism of bronchodilator effect in chronic airflow limitation.

OBJECTIVE: To examine the mechanisms through which two bronchodilators (theophylline and salbutamol) influence dyspnea during daily activities. METHODS: Twenty-four patients with chronic airflow limitation participated in a multiple crossover, randomized, placebo-controlled trial. The effect of theophylline and salbutamol, alone or combined, on pulmonary function and dyspnea during daily activities was examined. Correlations of changes in forced expiratory volume in 1 second (FEV1) and maximum expiratory pressures (MIPs) (independent variables) and changes in dyspnea score during daily activities (dependent variable) were also examined. RESULTS: The two drugs proved to be beneficial the effects in general were additive rather than synergistic. The drugs improved the FEV1; theophylline significantly improved the MIPs. The correlation between the changes in FEV1 and those in dyspnea score, after adjustment for the changes in MIPs, was 0.55 (p less than 0.001). The correlation between the changes in MIPs and those in dyspnea score, after adjustment for the changes in FEV1, was 0.39 (p less than 0.001). CONCLUSIONS: Changes in airway calibre and in respiratory muscle strength play an independent and important role in dyspnea during daily activities in patients with chronic airflow limitation. Changes in airway calibre may be of greater importance.

Activities of Daily Living↗
PubMed1991

Clinical usefulness of n-of-1 randomized controlled trials in patients with nonreversible chronic airflow limitation.

To determine if n-of-1 randomized controlled trials (n-of-1 RCT) are useful in the care of patients with nonreversible chronic airflow limitation (CAL). Individual trials had a double-blind, randomized, multiple crossover design. Patients with CAL were recruited from several respirology practices. For each individual trial the main outcome measure was a symptom questionnaire; peak flow measurements were used as a secondary measure. Physicians' plans of management (before and after trials) and confidence in the plans were determined. The proportion of trials that provided a definite clinical or statistical answer was established. Patients were followed, and long-term adherence to decisions based on n-of-1 RCT was examined. A total of 26 n-of-1 RCT in patients with CAL were attempted; 18 of these (69%) were completed. After 17 (94%) of the completed trials clinicians expressed a high degree of confidence in their management plans, confidence that was not, in any case, present before the trial. After 8 n-of-1 RCT (44% of all completed, or 31% of all trials) clinicians decided to stop the drug, which would otherwise have been continued indefinitely. In all 17 of the clinically definite n-of-1 RCT, the management decision that followed the trial was still being adhered to 40 months (on average) after completion of the trial. The results support the feasibility and usefulness of n-of-1 RCT in respirology practice.

Double-Blind Method↗
PubMed1991

Nasal polyposis: in search of a viral etiology using DNA hybridization.

The etiology of nasal polyps is unknown. Numerous theories have been proposed, with allergic and infectious causes predominant. A viral theory was postulated almost 40 years ago. In a pilot project, we studied 15 subjects comprising six controls and nine patients with nasal polyps. No known viruses were cultured from the nasal polyp tissue or nasal mucosal biopsies from the control subjects. DNA Hybridization for Epstein-Barr Virus, Herpes simplex virus, adenovirus type V, and Chlamydia trachomatis were also negative for all tissue studied. The use of molecular biological techniques is not widespread in otolaryngology and this is the first report, to the best of our knowledge, of the application of these techniques for the investigation of the viral etiology of nasal polyps.

Adult↗
PubMed1990

The n-of-1 randomized controlled trial: clinical usefulness. Our three-year experience.

OBJECTIVE: To review the feasibility and effectiveness of n-of-1 randomized controlled trials (n-of-1 trials) in clinical practice. DESIGN: Individual trials were double-blind, randomized, multiple crossover trials. The impact of n-of-1 trials was determined by eliciting physicians' plans of management and confidence in those plans before and after each trial. SETTING: Referral service doing n-of-1 trials at the requests of community and academic physicians. OBJECT of ANALYSIS: All trials were planned, started, and completed by the n-of-1 service. MEASURES OF OUTCOME: The proportion of planned n-of-1 trials that were completed and the proportion that provided a definite clinical or statistical answer. A definite clinical answer was achieved if an n-of-1 trial resulted in a high level of physician's confidence in the management plan. Specific criteria were developed for classifying an n-of-1 trial as providing a definite statistical answer. MAIN RESULTS: Seventy-three n-of-1 trials were planned in various clinical situations. Of 70 n-of-1 trials begun, 57 were completed. The reasons for not completing n-of-1 trials were patients' or physicians' noncompliance or patients' concurrent illness. Of 57 n-of-1 trials completed, 50 provided a definite clinical or statistical answer. In 15 trials (39% of trials in which appropriate data were available), the results prompted physicians to change their "prior to the trial" plan of management (in 11 trials, the physicians stopped the drug therapy that they had planned to continue indefinitely). CONCLUSION: We interpret the results as supporting the feasibility and usefulness of n-of-1 trials in clinical practice.

Adult↗
PubMed1990

Management of asthma and chronic airflow limitation: are methylxanthines obsolete?

The widespread popularity of methylxanthine derivatives should be reassessed in light of current evidence. These drugs are relatively weak bronchodilators, respiratory muscle stimulants and inotropic agents and adverse effects, sometimes life threatening, occur fairly frequently. In contrast, beta-2 adrenergic and anticholinergic bronchodilator aerosols used in asthma or chronic obstructive lung disease, and the prophylactic anti-inflammatory aerosols of corticosteroids and cromolyn provide a spectrum of therapeutic choices which address both the inflammatory and bronchoconstrictor components of acute and chronic airflow limitation. Aerosol bronchodilators, in general, are more potent, are virtually free of important side effects, and do not require costly serum level monitoring. Adrenoceptor agonists, together with inhaled steroids, should be considered first-line drugs of choice in managing patients with reversible airflow obstruction associated with asthma or COPD, while methylxanthines should be relegated to the position of third or fourth line drugs, if they are to be used at all. If they are, they should be used with great caution and close patient supervision and, even then, only if benefit, over and above the aerosol bronchodilators and inhaled anti-inflammatory agents can be demonstrated objectively.

Adrenal Cortex Hormones↗
PubMed1990

Pressurized aerosol versus jet aerosol delivery to mechanically ventilated patients. Comparison of dose to the lungs.

The purpose of this study was to compare deposition of aerosol to the lung from a metered-dose inhaler (MDI) and aerosol holding chamber and from a jet nebulizer in ventilator-dependent patients. Twenty-one patients were entered into the study, all receiving assisted ventilation and inhaled bronchodilators because of airflow limitation. The average age was 68 yr; there were 10 men and 11 women. The patients were randomized to receive either 4 puffs (800 micrograms) of radiolabeled fenoterol by MDI of 1.75 ml (1,750 micrograms) of radiolabeled fenoterol solution by nebulizer. Imaging of lung fields was made by a portable scintillation camera at 5-min intervals during the study. Results showed that 20 patients completed the study, 9 receiving fenoterol by MDI, and 11 by jet nebulizer. Four were excluded from analysis because of previous pneumonectomy, two from each group. Lung deposition measured as a percent of given dose from either system was 5.65 +/- 1.09 (mean +/- SEM) for MDI plus extension chamber and 1.22 +/- 0.35 for jet nebulizer (p less than 0.001). Therefore, this trial shows significantly greater efficiency of aerosol deposition to the lung in ventilator-dependent patients when using an MDI plus aerosol holding chamber than when using a jet nebulizer.

Aerosols↗
PubMed1990

Management of asthma and chronic airflow limitation. Are methylxanthines obsolete?

After almost 50 years as first-line drugs in the management of asthma and COPD, methylxanthines have been largely superceded by inhaled adrenoceptor agonist and anticholinergic bronchodilators which are more potent and far less toxic. Accumulating evidence indicates that intravenous theophylline contributes side effects, but is rarely of benefit in acute exacerbations of asthma or COPD. In the maintenance therapy of asthma, first-line therapy is dose-optimized inhaled steroids, reducing the need for bronchodilators. Inhaled adrenoceptor agonists are second line medications, anticholinergic aerosols third line, and theophylline, if needed at all, may fulfill a minor systemic steroid-sparing function in severe asthmatics on maximum doses of the inhaled medications. In the maintenance therapy of some patients with COPD, theophylline sometimes may be useful but these responders should be identified by objectively establishing therapeutic benefit. Since many patients have side effects from the methylxanthines, while their therapeutic benefit over and above dose-optimized inhaled therapy is marginal, their continued almost routine use in the management of reversible airflow obstruction is hard to justify, although this class of drugs may be useful in selected patients in whom both subjective and objective benefit can be demonstrated. In COPD, theophylline may improve exercise capacity in some patients by still incompletely understood mechanisms probably unrelated to bronchodilation.

Administration, Inhalation↗
PubMed1989

Chronic cough and gastroesophageal reflux.

We reviewed the charts of 20 patients with chronic cough of unknown cause who had been referred to a tertiary care respiratory centre from 1980 to 1984 to determine whether gastroesophageal reflux (GER) was a contributing factor. Fifteen of the patients complained of symptoms suggestive of GER: radiologic investigation of the upper gastrointestinal tract revealed hiatus hernia and GER in four, hiatus hernia alone in three, GER alone in two, decreased esophageal peristalsis in one and normal findings in four. Fibreoptic bronchoscopy in the four former smokers and one nonsmoker showed diffuse mucosal erythema. A chest x-ray film in one patient showed an infiltrate at the base of the right lung; transbronchial biopsy revealed vegetable material, which confirmed pulmonary aspiration. A 3-month course of medical antireflux treatment (dietary and lifestyle changes, elevation of the head of the bed and administration of cimetidine, antacid and metoclopramide) relieved the chronic cough in 14 of the 20 patients. Of the remaining patients one was lost to follow-up and five had GER confirmed by means of esophagoscopy, esophageal motility testing and long-term intraesophageal pH monitoring; four of the five patients underwent fundoplication and were asymptomatic 3 months after surgery. Antireflux therapy should be considered in patients with chronic cough when other causes have been ruled out, even if there are no GER symptoms. If the treatment fails, full investigation for GER is recommended; if GER is confirmed, surgery should be considered.

Adult↗
PubMed1989

Reliable salbutamol administration in 6- to 36-month-old children by means of a metered dose inhaler and Aerochamber with mask.

A double-blind study was performed to demonstrate that bronchodilator can be administered reliably to infants and children under 3 years of age from a metered-dose inhaler (MDI) by means of an economical valved aerosol-holding chamber device (Aerochamber) fitted with a mask. Symptoms of cough and breathlessness were compared for two 1-week crossover periods with the child either taking active drug or placebo. The MDI and Aerochamber with mask is an effective delivery system for respiratory therapy in these young children.

Administration, Inhalation↗
PubMed1989

Improvement in airway responsiveness and asthma severity during pregnancy. A prospective study.

In the myometrium and gut, smooth muscle becomes less contractile during pregnancy, probably because of the effect of progesterone and estrogen. It is not known whether these hormones cause similar changes in airway smooth muscle, and therefore, this study examined airway responsiveness during the large hormonal changes of pregnancy and evaluated whether changes in responsiveness are associated with changes in (1) progesterone and estrogen and (2) the clinical severity of asthma. Twenty nonpregnant asthmatic women were assessed every 3 months until conception. In the 16 who conceived, assessments were repeated once during the second and third trimesters and 1 month after delivery. Data collected preconception and from those who did not conceive within 1 yr were used for control subjects. There was a 2-fold improvement in airway responsiveness during pregnancy from a preconception mean PC20 0.35 to 0.72 mg/ml during the second trimester and 0.58 mg/ml during the third (p = 0.03). Post-delivery responsiveness (0.48 mg/ml) was not significantly different from preconception. The improvements during pregnancy were greater than the 3 monthly fluctuations when not pregnant (p = 0.04) and were greatest in those who were most hyperresponsive initially (p = 0.01). There was an associated improvement in clinical asthma severity as indicated by a reduction in minimum medication requirements (p = 0.03) and this was not at the expense of good symptoms control; both symptoms and spirometry remained unchanged during pregnancy. Changes in responsiveness were not closely related to progesterone or estriol, suggesting that other nonhormonal factors may also contribute to the improvement during pregnancy and that the control of asthmatic airway smooth muscle may not be exactly the same as that of the myometrium and gut.

Adult↗