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Biomedical subjects

A F Wilson

Publications and source records attributed to A F Wilson.

At least 163 records · Page 9Linked to original sources
PubMed1977

Large airway constriction in allergic rhinitis.

Extensive pulmonary function tests, including most of the sensitive new techniques capable of detecting small airways obstruction, were performed in 16 asymptomatic patients with allergic rhinitis and 31 normal control subjects. Mean flow rates, lung volumes, and results of tests measuring airways closure, distribution of ventilation, and diffusing capacity for carbon monoxide/alveolar volume did not differ significantly between the groups. Airways resistance (RAW) was significantly higher and specific conductance (SGAW) was significantly lower in subjects with rhinitis. Following administration of nebulized isoproterenol, RAW decreased (p less than 0.001) and SGAW increased (p less than 0.001) to mean values statistically indistinguishable from results obtained in control subjects. Individual results were normal for all tests except RAW and SGAW which were both abnormal in 3 subjects with rhinitis. The results of this investigation indicate that asymptomatic subjects with allergic have large airway (trachea and/or major bronchi) narrowing due to bronchoconstriction and no evidence of diffuse, or small airways, obstruction.

Airway Obstruction↗
PubMed1977

Clinical phase I study of the hypoxic cell radiosensitizer RO-07-0582, a 2-nitroimidazole derivative.

RO-07-0582 toxicity studies were performed in 12 patients for a total of 16 assays. Single and multifraction dose schedules were used, and drug concentrations in solid tumor tissue, cerebrospinal fluid, and blood (at 14 to 24 hr.) were established. A severe peripheral neuropathy occurred in 1 patient on the multifraction regimen when the total dosage reached 24 g. Drug absorption and concentration in the blood do not significantly differ from that of metronidazole. Maximum blood levels were reached at from 2 to 4 hr., and several days subsequent to administration had stabilized to levels only slightly above control levels.

Chondrosarcoma↗
PubMed1977

Volume of isoflow: effect of distribution of ventilation.

Volume of isoflow was determined in smokers and nonsmokers following one (VisoV1) and three (VisoV3) inhalations 80% helium 20% oxygen. In addition, distribution of ventilation was measured by single breath nitrogen washout and end-tidal helium concentration was determined following 1-3 breaths of a helium-oxygen mixture. In all subjects (smokers and non smokers), VisoV1 was significantly higher than VisoV3. Furthermore, VisoV1 was abnormal in 55.6% of smokers, whereas VisoV3 was abnormal in only 38.9%. Differences between VisoV1 and VisoV3 (VisoV1 - VisoV3 = deltaVisoV) were significantly larger in smokers. Non-uniform distribution of ventilation was associated with larger values of delta VisoV and lower end-tidal helium concentrations. VisoV1 is a more effective method than VisoV3 in distinguishing smokers with small airways obstruction from nonsmokers. This enhanced sensitivity can be explained by the observation that the effects of maldistribution of ventilation upon helium concentration in the late expirate are minimized after three breaths of a helium-oxygen mixture.

Adult↗
PubMed1977

Pulmonary parenchymal tissue volume in normal subjects. The effect of age and sex.

Pulmonary parenchymal tissue volume (Vt) and pulmonary capillary blood flow were determined by the acetylene-inhalation technique of Cander and Forster in 66 normal subjects (31 male and 35 female subjects) ages 8 to 66 years. In subjects under the age of 20 years, values for Vt, when factored by alveolar volume (VA) to correct for differences in body size, were essentially identical in both male and female subjects (0.248 +/- 0.039 in male subjects and 0.242 +/- 0.079 in female subjects). In subjects between the ages of 21 and 40 years, Vt/Va was significantly lower in men than women, 0.125 +/- 0.057 vs 0.193 +/- 0.046 (P less than 0.001), respectively. In subjects over the age of 41 years, although Vt/VA increased, there was no significant difference between the sexes; ie, Vt/VA decreased with advancing age up to the age of 35 years (more so in male than female subjects) and then increased back to pubertal values. The reason for the intersex changes is a greater increase of VA in male than female subjects for the same Vt. The reasons for the increase in Vt/VA in subjects over the age of 35 years are obscure.

Adolescent↗
PubMed1977

A comparative study of the aerosolized bronchodilators, isoproterenol, metaproterenol and terbutaline in asthma.

Twenty-one patients with asthma were studied in a double-blind manner for the effects of three aerosolized bronchodilators (isoproterenol, metaproterenol and terbutaline) on small, large and mixed airways, blood pressure, heart rate and various blood chemistries. Favorable responses were measured within 30 seconds for each drug. However, only the newer, selective beta-2 agonists, metaproterenol and terbutaline, produced significantly prolonged action upon small as well as large airways and lung volumes. Of the two, terbutaline tended to have an earlier and higher peak activity and longer duration of action, especially on large airways. Such prolonged activity by the newer agents suggests a safer and more effective alternative to isoproterenol inhalation.

Adolescent↗
PubMed1976

Endogenous caloric sources and nitrogen balance: regulation in postoperative patients.

Twenty-three postoperative patients were divided into three groups to evaluate the peripheral vein administration of solutions containing glucose, amino acids, or glucose and amino acids. Serum insulin, glucose, and nitrogen balances were monitored in each patient. Serum insulin concentrations rose on the first postoperative day in all three groups, then fell to near preoperative levels by the third day after surgery. Negative nitrogen balance was most pronounced in patients recieving glucose only. Patients receiving only amino acids had a reduction in nitrogen balance, but some protein catabolism was present. The mean nitrogen balance in patients who received a combination of these solutions was positive on days one and two after surgery and slightly negative on the third postoperative day. These changes were not significantly better than the amino acid group. However, the combination group had 12 to 21 days of positive balance, as compared to seven of 20 days in the amino acid group. Since starvation adaptation accurs gradually, it is concluded that the simplest and safest way to reduce protein catabolism in the immediate postoperative period is by the peripheral intravenous administration of both glucose and amino acids.

Adaptation, Physiological↗
PubMed1976

Cardiopulmonary effects of long-term bronchodilator administration.

Because of reports of drug tolerance occurring with chronic use of adrenergic agents in asthma, we investigated cardiopulmonary responsiveness to ephedrine and to the beta-2 agent, tebutaline, following chronic drug administration for periods up to one year. With chronic drug administration baseline (prior to daily medication) FEV increased 19% in the terbutaline group and 3.5% in the ephedrine group. An additional increase of FEV above baseline of 23% for terbutaline and 12% for ephedrine was noted after daily medication. Terbutaline also had a longer duration of effect; peak response after ephedrine occurred at 2 hr while terbutaline effect was maximal at 3 to 4 hr. There was no evidence for reduced responsiveness to the bronchodilator actions of either drug at any time. Despite prolonged use, both drugs continue to increase heart rate and pulse pressure moderately following ingestion, with a peak effect occurring at 3 hr; however, pulse pressure widened after terbutaline because of a diastolic fall, while the major effect of ephedrine was to increase systolic pressure. Baseline blood pressure, particularly diastolic, declined progressively with continued drug use. No evidence of cardiac, ehpatic, renal, or ophthalmologic toxicity or change in need for other bronchodilator agents was noted during the study with either drug.

Asthma↗
PubMed1976

Paraquat poisoning: new aspects of therapy.

Clinical, laboratory, and pulmonary physiologic features of three fatal cases of paraquat poisoning are presented. Experimental investigations and clinical experience would suggest several possible means of modifying paraquat toxicity. The following specific therapeutic interventions, several of which had previously been applied only in experimental circumstances, were used: (1) inhibition of absorption of paraquat with Fuller's Earth and catharsis by magnesium sulfate, (2) elimination of absorbed paraquat by hemodialysis with ultrafiltration and forced diuresis, (3) competition by d-propranolol for tissue binding sites, (4) modification of direct pulmonary tissue effects of paraquat by hypoxic breathing mixtures, superoxide dismutase, and corticosteroids. Treatment was unsuccessful. However, our clinical experience and data concerning paraquat concentration in body and dialysis fluids suggest a therapeutic approach aimed at preventing early and progressive tissue damage. A combination of Fuller's Earth and magnesium sulphate should be used immediately and in frequently repeated doses to prevent absorption. Diuresis and haemodialysis should be instituted as soon as possible to increase excretion. Hypoxic atomspheres should be created urgently to produce a PaO2 of 40-45 mmHg, and the use of superoxide dismutase be further investigated. It is hoped that the high mortality of paraquat poisoning will be modified by this combined approach of early and intensive treatment.

Adolescent↗
PubMed1975

Guillan-Barré syndrome in heroin addiction.

In two cases of Guillain-Barré syndrome (acute polyneuritis) as a complication of narcotic abuse, the onset of paralysis began approximately 4 and 12 hours after self-administration of opiates intravenously. Bulbar and respiratory paralysis developed in one patient and required prolonged ventilation therapy; the other patient had peripheral muscular and unilateral facial weakness, with notable pleocytosis was present in both.

Adolescent↗
PubMed1975

Continuous spectrophotometric measurements of arteriovenous oxygen difference.

A relatively inexpensive dual-beam optical absorbance monitor was tested and adapted to measure arterio-enous oxygen difference ((a - v)delta O2). Since the molar extinction coefficients of oxy- and deoxyhemoglobin are markedly different at 660 nm, the difference in optical density between arterial and venous blood, as measured by the absorbance monitor, was shown to be linearly related to (a - v)delta02. When appropriate cuvettes (optical path length = 0.5 mm) were used, the instrument's 90% response time (4.4 s) was sufficiently rapid for most physiological applications such as Fick determinations of the rate of an organ's oxygen consumption. The theoretical basis of this spectrophotometric (a - v)deltaO2 measurement and sources of error are discussed in detail.

Animals↗
PubMed1975

Transcendental meditation and asthma.

A 6-month study with crossover at 3 months was designed to evaluate the possible beneficial effects of transcendental meditation upon bronchial asthma. 21 patients kept daily diaries of symptoms and medications and answered questionnaires at the end of the study and 6 months later. Other measurements included physician evaluation, pulmonary function testing, and galvanic skin resistance. The results indicated that transcendental meditation is a useful adjunct in treating asthma.

Airway Resistance↗
PubMed1975

Pulmonary parenchymal tissue volume measurements in graded degrees of pulmonary edema in dogs.

We investigated the accuracy and the sensitivity of a modification of the acetylene inhalation technique for the determination of lung tissue volume (Vt) during various grades of hemodynamic pulmonary edema in 23 dogs. After base-line acetylene measurements were obtained, intravascular driving force (pulmonary wedge pressure minus intravascular colloid osmotic pressure) was varied between -8 and +71 mm Hg by the inflation of an intra-aortic ballon and the infusion of isotonic saline. After 30 minutes at this new driving force, four timed acetylene samples were again collected. Vt (when factored by alveolar volume, VA) increased from base line to 0.23 plus or minus 0.07 ml/ml between a driving force of 0 and + 17 mm Hg. This same change in Vt/VA was accompanied by an increase in the lung wet weight-dry weight ratio from 3.84 plus or minus 0.31 to 5.2 plus or minus 0.25. Vt was 271 plus or minus ml compared with an actual lung wet weight of 288 plus or minus 57 g; Vt tended to overestimate lung wet weight in severe pulmonary edema. Alloxan-induced pulmonary edema (6 dogs) tended to parallel these data. We conclude that the acetylene method may ve a relatively accurate noninvasive method for the determination of increasing lung water in pulmonary edema.

Acetylcholine↗
PubMed1975

Failure of isoniazid prophylaxis after exposure to isoniazid-resistant tuberculosis.

We report the failure of isoniazid chemoprophylaxis to prevent the development of active pulmonary tuberculosis and tuberculin conversion in contacts of patients infected with isoniazid-resistant strains of Mycobacterium tuberculosis. Although failure of isoniazid chemoprophylaxis has been reported rarely in contracts of isoniazid-resistant tuberculosis, the cases reported here as well as previous observations by others suggest that isoniazid chemoprophylaxis for contracts of patients with isoniazid-resistant tuberculosis may not be effective and that other agents must be considered. Initial chemotherapy of active pulmonary tuberculosis in contacts of known drug-resistant patients should be based on drug susceptibility studies in the index case.

Adolescent↗
PubMed1975

Mortality prediction in adult respiratory insufficiency.

The results of treatment of acute respiratory insufficiency in the adult must be quantitated before indications for innovative treatment (such as extracorporeal oxygenation) can be defined. A method for retrospective and prospective data collection based on a graph of A-a gradient and time was evaluated in 45 patients. From this graph a pulmonary insufficiency index (PII) can be calculated which correlates well with mortality in this series. The mean PII of surviving patients was 0.84 and the highest value was 2.75. The mean PII of patients who died with pulmonary insufficiency was 15.9; the lowest value was 6.0. Using this method with a larger data base, it will be possible to predict mortality based on PII facilitating the study of ongoing management and innovative treatment methods.

Carbon Dioxide↗