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Biomedical subjects

D H Bryant

Publications and source records attributed to D H Bryant.

At least 37 records · Page 2Linked to original sources
PubMed1987

Pulmonary manifestations of the acquired immunodeficiency syndrome.

Between 1983 and 1985, 71 patients with the acquired immunodeficiency syndrome (AIDS) were evaluated. Pulmonary manifestations were present in 42 patients (59%). Pneumocystis carinii pneumonia (PCP) was the most common pulmonary manifestation, present in 32 patients (45%). Other pulmonary findings were cytomegalovirus pneumonia (one patient), Candida pneumonia (one patient), cryptococcal pneumonia (one patient), bacterial pneumonia (three patients), nonspecific pneumonitis (three patients), Kaposi's sarcoma (one patient), and non-Hodgkin's lymphoma (one patient). The presenting features of PCP were reviewed and in seven patients the chest X-ray and blood gases were normal at the time of diagnosis of PCP. Bronchoscopy was a safe and useful technique for obtaining specimens for diagnosis promptly, and a combination of samples obtained by bronchial washings/brushings and transbronchial biopsy was found to give a higher diagnostic yield than any single sample. Drug side-effects were common during therapy, requiring change of therapy in 16 patients. At one month after diagnosis 16% of patients with PCP had died. PCP is a common pulmonary manifestation in patients with AIDS which is treatable and has an initially favourable outcome.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Effect of hypo- and hyper-osmolarity on basophil histamine release.

The pattern of histamine release from peripheral white blood cells in response to hyper-(sodium chloride, mannitol) and hypo-osmolar (water) stimuli was studied in order to determine the differences between non-atopic control and atopic asthmatic patients in histamine release caused by osmolar changes. All subjects showed histamine release to both hyper- and hypo-osmolar stimuli and this response was reproducible. Viability studies and the effect of time and temperature indicated that, at the extremes of hypo- and hyper-osmolality, histamine release was associated with cell cytotoxicity. Asthmatics and controls showed no differences either in their level of spontaneous or hyper-osmolar sodium chloride induced histamine release, but asthmatics' cells were more responsive to mannitol over 600-800 mOsm/kg and less responsive to a hypo-osmolar stimulus under 80 mOsm/kg. This suggests that asthmatics' cells may differ from controls in th manner in which they respond to osmotic stimuli and this may be relevant in certain clinical situations.

Adult↗
PubMed1985

Occupational asthma.

A brief review of the definition, prevalence, predisposing factors, clinical features and possible causes of occupational asthma is presented, together with an overview of the appropriate steps in the management of this condition. In terms of the prognosis, the need for effective prevention and early detection of sufferers is emphasized.

Asthma↗
PubMed1985

Asthma due to insecticide sensitivity.

Two patients are reported in whom asthma was precipitated by exposure to synthetic organophosphorous insecticides. Investigation showed no evidence of systemic poisoning or cholinesterase inhibition and indicated that the asthmatic reactions may have been due to a sensitivity response. The mechanism of this response is unknown but it was inhibited by corticosteroids in one patient. A history of insecticide exposure was obtained from the affected patients only after careful questioning and indicates the need for awareness that sensitivity to insecticides may precipitate asthma and that little exposure is necessary to elicit a response.

Adult↗
PubMed1985

Nebulized ipratropium bromide in the treatment of acute asthma.

The aim of this study was to investigate the effects of nebulized ipratropium in patients with acute asthma in order to determine whether it augments the bronchodilator effect of a beta agonist drug. A total of 28 patients with acute asthma were randomly allocated to treatment every six hours with either 1 mg nebulized fenoterol (group A) or 1 mg fenoterol and 0.5 mg ipratropium (group B). There was no significant difference between the mean FEV1 of the two groups prior to treatment and increasing the dose of fenoterol from 1 mg to 2 mg did not increase the response. However the mean change in FEV1 after 48 hours (expressed as a percentage of the predicted maximal response) was 40.1 +/- 7.2 percent in group A and 54.3 +/- 9.2 percent in group B (p less than 0.005). It was concluded that the response of patients with acute asthma to fenoterol was significantly enhanced by the addition of the anticholinergic agent ipratropium bromide.

Acute Disease↗
PubMed1984

Allergies, mediators and asthma.

Asthma is a term that has been used for centuries to describe states of breathlessness associated with wheezing. However, there are well-known difficulties in defining asthma, as it encompasses such a broad clinical spectrum ranging from mild, rapidly reversible, bronchospasm to severe, intractable, chronic airflow obstruction. Moreover, reversibility of airflow obstruction, a cardinal feature used to identify asthma, may be demonstrated only with difficulty in certain cases, such as severe, acute asthma attacks, which necessitate several days of treatment before any reversibility can be achieved.

Airway Resistance↗
PubMed1982

Histamine content of sputum from patients with asthma and chronic bronchitis.

Studies using the guinea pig ileum bioassay technique have previously shown that patients with either asthma or chronic bronchitis have increased amounts of histamine in their sputum. Because of the limitations of this assay technique, a spectrofluorometric method for measuring the histamine content of sputum was developed. Using this technique it was found that the mean histamine concentration of sputum from patients with bronchogenic carcinoma or pneumonia was not significantly different from the mean value for sputum collected during a remission phase from patients with either chronic bronchitis or asthma. However, the mean values in patients with asthma or chronic bronchitis during an exacerbation were significantly higher and returned to basal values as the airways obstruction improved. There was no significant difference in sputum histamine concentration between those patients with extrinsic atopic asthma and those with late onset cryptogenic asthma during as exacerbation although the value in patients with an exacerbation of chronic bronchitis was significantly less. These results indicate that mediators of immediate hypersensitivity may be implicated in the pathogenesis of airways obstruction in disorders other than extrinsic atopic asthma and suggest that histamine release may occur in non-atropic subjects in response to non-antigenic stimuli.

Albuterol↗
PubMed1977

Cutaneous eosinophil accumulation in atopic and non-atopic individuals: the effect of an ECF-A tetrapeptide and histamine.

The numbers of eosinophils recruited locally to abraded human skin were measured in eight atopic and eight non-atopic volunteers, at time intervals over 24 hr, following the application of an ECF-A tetrapeptide (Val-Gly-Ser-Glu) or histamine. In all subjects the higher doses of the peptide (10(-4) and 10(-6) mol/l) or histamine (10(-3) and 10(-5) mol/l) produced significantly greater counts than the Tyrode's diluent alone. The counts produced with the lowest dose of peptide (10(-8) mol/l) or histamine (10(-7) mol/l) were not significantly different from the control. The peptide or histamine evoked a greater local eosinophilia in the atopics than the non-atopics. This effect was probably independent of the peripheral blood eosinophil counts since at the time of study the numbers of circulating eosinophils between the two groups were not significantly different. In the atopics, histamine in doses of 10(-3) and 10(-5) mol/l were required to give the same eosinophil response as that obtained with 10(-4) and 10(-6) mol/l of the peptide, respectively. It is suggested that the relative paucity of eosinophils recruited by locally applied ECF-A peptide or histamine, when compared to antigen-induced eosinophilia, is due either to an inability to mimic the events associated with the release of these mediators from mast-cells or the involvement of other pharmacological agents.

Chemotaxis, Leukocyte↗
PubMed1977

False positive complement fixation tests with respiratory virus preparations in bird fanciers with allergic alveolitis.

False positive raised complement fixation titres to egg-grown virus preparations were found in six pigeon fanciers suffering from extrinsic allergic alveolitis but not in six similar budgerigar fanciers. The raised titres in the pigeon fanciers fell fourfold over a short interval in the absence of avian exposure and were attributable to antibodies directed against antigens from hen's egg in which the test virus preparations were grown. Such antigens were shown to be present in the virus preparations. In view of the clinical similarities between influenza and acute extrinsic allergic alveolitis, it is essential that a diagnosis of influenza in bird fanciers is not based on either a single raised titre or a fourfold fall in complement fixation titre without appropriate control tests with avian antigens.

Alveolitis, Extrinsic Allergic↗
PubMed1976

Pneumonia in a city hospital.

Of 222 patients with pneumonia in St Vincent's Hospital, Sydney, in 1972, more were affected by bronchopneumonia (53%) than lobar pneumonia (46%). Two-thirds of the patients were males and 86% were aged 40 years or more. Only 59% had any bacteriological studies performed. It was unusual to isolate pathogens from persons who had received antibiotics before cultures were taken, but of cultures taken from persons not receiving antibiotics, 65% yielded pneumococci. Infections due to Staphylococcus aureus, pseudomonas and enterobacteria were uncommon. Haemophilus influenzae appeared to be a co-pathogen in bronchopneumonia more than in lobar pneumonia. The mortality in lobar pneumonia was acceptably low (4%), but was generally high in bronchopneumonia, being 32% when the condition occurred after surgical operations and 35% when this form of pneumonia complicated other normally non-terminal medical diseases. The mortality was 17% in primary bronchopneumonia.

Adult↗
PubMed1976

Skin-prick test reactions to inhalant allergens in asthmatic patients.

Skin-prick tests with extracts of a large number of inhalant allergens were carried out on 489 asthmatic patients attending the thoracic outpatient clinics at two Sydney hospitals. Positive reactions, which had been previously found to be invariably accompanied by bronchial immediate allergic reactivity, occurred in 98% of patients who had had symptoms of asthma since the first decade of life, and in 28% of those whose symptoms did not begin until after the age of 60 years. Prick-test reactions were most commonly produced by house dust and house dust mite (70%), followed by grass pollens (50%), moulds (30%), weed pollens (35%) and tree pollens (22%). The patients commonly gave positive reactions to two or more of the extracts from within each of those allergen groups.

Adolescent↗
PubMed1976

The relationship between bronchial histamine reactivity and atopic status.

It has been proposed that increased production of IgE, a feature of atopy, is a cause of the non-specific bronchial hyper-reactivity that is characterisitc of asthma. This hypothesis was examined by selecting groups of subjects with asthma or rhinitis and a group of healthy control subjects and studying the relationship between their bronchial histamine reactivity and their atopic status. In none of the groups tested was there a significant association between the degree of bronchial histamine reactivity and either the serum level of total IgE or the number of extracts of aeroallergens giving positive prick test reactions.

Asthma↗
PubMed1976

Bronchial histamine reactivity: its relationship to the reactivity of the bronchi to allergens.

The aim of this study was to examine the proposal that the magnitude of the response of the bronchi to an immediate allergic reaction depends not only on the degree of sensitization of the bronchi by allergen specific IgE antibody but also on the reactivity of the bronchi to the vasoactive mediators which are released during immediate allergic reactions. This was done by determining the bronchial reactivity to Dermatophagoides pteronyssinus and to histamine of both symptomatic and asymptomatic groups of atopic subjects who had comparable serum levels of D. pteronyssinus specific IgE. Positive bronchial responses to the D. pteronyssinus extract were recorded with both the symptomatic and asymptomatic subjects, the mean bronchial threshold dose of allergen being significantly higher in the asymptomatic than in the asthmatic patients. There was a highly significant correlation between the serum level of allergen specific IgE and the bronchial threshold dose of allergen extract and also between the bronchial threshold dose of allergen extract and of histamine in all groups of subjects. The ability to predict bronchial reactivity to the allergen from the serum level of allergen specific IgE within each group was significantly better if the bronchial reactivity to histamine was included in the correlation analysis. This supports the hypothesis that whether a particular subject who is producing specific IgE antibody will develop symptoms on the inhalation of that allergen depends not only on the amount of allergen which he inhales and on the degree of sensitization of his bronchi but also on the reactivity of his bronchi to the vasoactive mediators which are released by allergen-IgE interaction.

Administration, Intranasal↗