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Biomedical subjects

T R Bai

Publications and source records attributed to T R Bai.

49 records · Page 3Linked to original sources
PubMed1988

The basidiomycete ganoderma and asthma: collection, quantitation and immunogenicity of the spores.

Ganoderma fungal spores are a major component of the Auckland air-spora. Previous studies of ganoderma involvement in allergic asthma and rhinitis were extended by locating the sporophores (fruiting bodies) in the Auckland area and systematically collecting the ejected spores. Maximum production by one sporophore was 5 gram dry weight of spores in one week, equivalent to 11 billion spores. We have estimated that between 400 and 1200 sporophores would account for previously reported levels of ganoderma spores collected from the air by Burkhard spore traps. Both whole spores and extracts of spores were strongly immunogenic in rabbits. Of the 115 asthma patients who were skin prick tested with a variety of fungal extracts, 32 (28%) were positive to one or more fungi. Of these, 18 (16%) reacted positively to ganoderma extracts. A theory proposing how ganoderma might contribute to allergic hyperreactivity in susceptible patients is developed.

Air Microbiology↗
PubMed1987

Airway responses to aerosolized methacholine in the cat. Effects of partial or complete vagosympathectomy.

To explore the role of airway innervation as a determinant of airway responsiveness to inhaled cholinergic agonists, we studied the effects of partial or complete section of the cervical vagosympathetic trunk on the magnitude of methacholine-induced bronchoconstriction in the chloralose-urethane-anesthetized, mechanically ventilated cat. An initial concentration-response curve to methacholine was constructed to identify the concentration required to cause a twofold to threefold rise in mean pulmonary resistance (RL). Using this concentration, 3 consecutive challenges (C1, C2, and C3) were then performed at 30-min intervals in 4 groups of cats. After a control challenge (C1), the parasympathetic (n = 9), sympathetic (n = 6), or both branches (n = 4) of the cervical vagosympathetic trunks were sectioned. Sham cats (n = 7) showed reproducible increases in RL (C1, delta RL = 15.1 +/- 2.7 cm H2O X 1(-1) X s; C2, delta RL = 15.7 +/- 3.0; C3, delta RL = 13.1 +/- 2.9; mean +/- 1 SE). After parasympathectomy there was an increase in responsiveness after C3 (C1, delta RL = 15.0 +/- 4.3; C2, delta RL = 16.4 +/- 6.4; C3, delta RL = 29.9 +/- 11.6; p less than 0.01). Sympathectomy and vagosympathectomy did not significantly alter responsiveness. The results suggest that vagally mediated inhibitory influences modulate the bronchial response to aerosolized methacholine in the cat.

Aerosols↗
PubMed1986

The effects of parasympathectomy on serotonin-induced bronchoconstriction in the cat.

We studied the contribution of neural influences, in particular, the nonadrenergic, noncholinergic inhibitory system, on the modulation of airway responses to serotonin (5-HT) in the anesthetized and mechanically ventilated cat. Airway responses were assessed by measurement of pulmonary resistance (RL). Parasympathectomy (PS) caused a variable increase in bronchoconstriction in 9 of 10 cats (n = 10) that had received pretreatment intravenously with atropine (3 mg/kg) and propranolol (2 mg/kg); PS performed following pretreatment with phentolamine (2 mg/kg), propranolol, and atropine led to an increase in bronchoconstriction in only 2 of 6 cats. Dose-response curves to aerosolized 5-HT were performed in one group of cats (n = 5) before and 30 min after PS and in control group (n = 6). Both groups of animals were pretreated intravenously with atropine, propranolol, and phentolamine. The concentration of aerosolized 5-HT that was necessary to double pulmonary resistance (ED200RL) was significantly reduced from 0.117 to 0.062 mg/ml (p less than 0.01) by PS, in contrast to control cats in which ED200RL during 2 consecutive dose-response curves (0.076 and 0.087 mg/ml, respectively) did not change significantly. We conclude that there is neural modulation of airway responses to infused 5-HT through an alpha-adrenergic pathway and that an additional inhibitory nonadrenergic, noncholinergic neural influence is demonstrable in the response to aerosolized 5-HT.

Aerosols↗
PubMed1985

Central and local cholinergic components of histamine-induced bronchoconstriction in dogs.

To determine the importance of central and local reflexes in the bronchoconstriction produced by inhaled aerosolized histamine, chloralose-urethan-anesthetized dogs were intubated with a double-lumen catheter, ventilated with a dual cylinder respirator, and instrumented for the measurements of pulmonary conductance (GL) and dynamic compliance (Cdyn) in each lung. In each dog, dose-response curves to inhaled aerosolized histamine were obtained in both lungs separately but synchronously. Four series of experiments were performed. In the first series (n = 10) the responses of the right and left lungs were compared and found to be approximately equal, indicating that one lung could be used as a control for the other. In the second and third series the dose-response curve of one lung that had either been treated with inhaled atropine sulfate (n = 6) (4 mg/ml) or vagotomized (n = 4) was compared with the contralateral control lung. At low concentrations of histamine, GL and Cdyn decreased more in the control lungs than in their atropine-treated or vagotomized counterparts, and approximately 40% of the bronchoconstriction induced was reflex in origin. At higher concentrations of histamine the responses of the control and atropine-treated or vagotomized lungs were not significantly different. In the fourth series of experiments (n = 6) histamine dose-response curves were obtained following combined bilateral vagotomy and unilateral delivery of inhaled aerosolized atropine. In these dogs GL, but not Cdyn, fell to a greater extent in the control than in the atropine-treated lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Near-maximal voluntary hyperpnea and ventilatory muscle function.

Because of its potential relevance to heavy exercise we studied the ventilatory muscle function of five normal subjects before, during, and after shortterm near-maximal voluntary normocapnic hyperpnea. Measurements of pleural and abdominal pressures and diaphragm electromyogram (EMG) during hyperpnea and of maximum respiratory pressures before and after hyperpnea were made at four levels of ventilation: 76, 79, and 86% maximal voluntary ventilation (MVV) and at MVV. Measurements of pleural and abdominal pressures and diaphragm electromyogram (EMG) during hyperpnea and of maximum respiratory pressures before and after hyperpnea were made. The pressure-stimulation frequency relationship of the diaphragm obtained by unilateral transcutaneous phrenic nerve stimulation was studied in two subjects before and after hyperpnea. Decreases in maximal inspiratory (PImax) and transdiaphragmatic (Pdimax) strength were recorded posthyperpnea at 76 and 79% MVV. Decreases in the pressure-frequency curves of the diaphragm and the ratio of high-to-low frequency power of the diaphragm EMG occurred in association with decreases in Pdimax. Analysis of the pressure-time product (P X dt) for the inspiratory and expiratory muscles individually indicated the increasing contribution of expiratory muscle force to the attainment of higher levels of ventilation. Demonstrable ventilatory muscle fatigue may limit endurance at high levels of ventilation.

Abdomen↗
PubMedDate not supplied

What is new since the last (1999) Canadian Asthma Consensus Guidelines?

The objective of the present document is to review the impact of new information on the recommendations made in the last (1999) Canadian Asthma Consensus Guidelines. It includes relevant published studies and observations or comments regarding what are considered to be the main issues in asthma management in children and adults in office, emergency department, hospital and clinical settings. Asthma is still insufficiently controlled in a large number of patients, and practice guidelines need to be integrated better with current care. This report re-emphasises the need for the following: objective measures of airflow obstruction to confirm the diagnosis of asthma suggested by the clinical evaluation; identification of contributing factors; and the establishment of a treatment plan to rapidly obtain and maintain optimal asthma control according to specific criteria. Recent publications support the essential role of asthma education and environmental control in asthma management. They further support the role of inhaled corticosteroids as the mainstay of anti-inflammatory therapy of asthma, and of both long acting beta2-agonists and leukotriene antagonists as effective means to improve asthma control when inhaled corticosteroids are insufficient. New developments, such as combination therapy, and recent major trials, such as the Children's Asthma Management Project (CAMP) study, are discussed.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Respiratory failure associated with the lipodystrophy syndrome in an HIV-positive patient with compromised lung function.

Protease inhibitors, used as treatment in human immunodeficiency virus (HIV) infection, are associated with a syndrome of peripheral lipodystrophy, central adiposity, hyperlipidemia and insulin resistance. An HIV-positive patient with chronic obstructive pulmonary disease is presented who developed the lipodystrophy syndrome that is associated with the use of protease inhibitors. It is postulated that the lipodystrophy syndrome further compromised his lung function, leading to respiratory failure. Patients who have pulmonary disease and are taking protease inhibitors require monitoring of clinical status and pulmonary function tests.

Adult↗
PubMedDate not supplied

Bullae, bronchiectasis and nutritional emphysema in severe anorexia nervosa.

STUDY OBJECTIVES: Pulmonary complications of anorexia nervosa are rarely documented. The case of a patient with anorexia nervosa and pulmonary disease is presented, a new quantitative computed tomography (CT) method for the detection of emphysema is employed, the literature is reviewed and the concept of 'nutritional' emphysema is discussed. RESULTS: The case of a 34-year-old, nonsmoking woman with long-standing severe anorexia nervosa who was evaluated for cough and progressive shortness of breath is reported. Pulmonary function testing showed a predominant restrictive pattern with a marked reduction in carbon monoxide transfer and respiratory muscle strength, and an elevated residual volume. Imaging revealed bullae and bronchiectasis, and quantitative analysis of the CT scan was consistent with mild, generalized emphysema. Bronchial washings grew Pseudomonas aeruginosa. Known causes for bronchiectasis were excluded. A literature review disclosed few reported noninfectious pulmonary complications of anorexia nervosa. CONCLUSIONS: To the authors' knowledge, this is the first report of bullae and bronchiectasis in a patient with anorexia nervosa, and the CT analysis was consistent with mild emphysema. Malnutrition has been associated with emphysematous changes in animals and may be the primary insult in the development of emphysema, bullae and bronchiectasis in the present patient.

Adult↗