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Biomedical subjects

M G Prichard

Publications and source records attributed to M G Prichard.

10 recordsLinked to original sources
PubMed1987

Compartmental analysis of resting and activated pulmonary natural killer cells.

Conflicting reports exist regarding the activity of natural killer (NK) cells in resting lung. We speculated that use of cells from differing lung compartments in past studies might have contributed to these discrepancies. To address this issue, a compartmental analysis of relative NK activity of airspace (bronchoalveolar lavage) cells versus interstitial lung cells was conducted in guinea pigs. Non-pulmonary (spleen) cells were also assayed for NK activity. For assays, cells were obtained from each compartment in the same host, then assayed concomitantly using a chromium release assay with the tumor target cell line, K562. Virtually identical NK cell activity was demonstrated by cells derived from airspaces and lung interstitium. This activity was significantly less (p less than 0.05) than that of spleen cells, and its expression required periods of effector: target cell contact which were considerably longer (16 hr) than those needed for spleen cells (4 hr). Further experiments documented the capacity for augmentation of airspace NK cell activity by intratracheal instillation of interferon inducers poly I:C and carboxymethyl acridanone. We conclude that resting guinea pig pulmonary NK cells have low activity relative to systemic cells, that no significant difference in activity exists among NK cells in airspace and interstitial compartments, and that local activation of airspace NK cells is possible using intratracheal interferon inducers.

Acridines↗
PubMed1985

Skin test and RAST responses to wheat and common allergens and respiratory disease in bakers.

Interrelationships between skin and humoral tests for immediate hypersensitivity to wheat and indicators of respiratory disease were examined in 176 male bakers. Skin tests were assessed by measuring the diameter of the weal resulting from prick innoculation of allergen extract and circulating allergen-specific IgE by radioallergosorbent test (RAST). Fifteen per cent of subjects showed positive skin-prick test responses to wheat extracts. These subjects demonstrated an increased prevalence of respiratory symptoms and of measurable bronchial responsiveness to methacholine. Thirty per cent of subjects had positive skin test responses to common allergens but negative responses to whole wheat. Compared to subjects with no positive skin test responses they had an increased prevalence of bronchial responsiveness to methacholine but a similar prevalence of respiratory symptoms. There was a significant association between skin test responses to whole wheat and skin test responses to common allergens suggesting that bakers with pre-existing sensitivity to common allergens are at increased risk of developing wheat flour sensitization. There was no significant difference between skin-prick test and RAST responses to wheat, water-soluble wheat protein and common allergens. Both tests showed similar relationships with indices of respiratory disease. The associations between skin test and RAST responses to wheat extracts and indices of respiratory disease was stronger for the water-soluble wheat proteins than for other wheat grain extracts. These results suggest that immediate hypersensitivity to wheat flour is important in the development of non-specific bronchial hyperreactivity in bakers and that the water-soluble fractions of wheat flour are the most important allergenic components.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Wheat flour sensitisation and airways disease in urban bakers.

A total of 176 bakers and 24 subjects employed as bread slicers and wrappers were studied to examine the effect of occupational category on respiratory symptoms, ventilatory capacity, non-specific bronchial reactivity, and prick skin test responses to wheat and common allergens. Bakers had a greater prevalence of attacks of wheeze and dyspnoea and more frequently considered that work affected their chests than did slicers and wrappers. Bakers with a history of asthma with onset since starting work in a bakery had a greater prevalence of chronic cough and sputum, increased bronchial reactivity, and positive prick skin test responses to wheat and common allergens than other bakers. There was a significant association between the frequency of positive prick skin tests to wheat and common allergens, suggesting that prior atopy facilitates sensitisation to cereal antigens. The frequency of positive prick skin responses to common allergens, however, declined with increasing baking duration whereas the frequency of positive skin responses to wheat increased with increasing baking duration, suggesting that subjects who were sensitised to common allergens were leaving the industry whereas subjects who stayed in the industry increased their risk of developing sensitisation to wheat. Oven handlers had a greater prevalence of attacks of wheeze and dyspnoea and more frequently considered that work affected their chests than either dough makers or general bakers. They also had a greater prevalence of positive prick skin test responses to wheat than dough makers or general bakers. Oven handlers also had a lower mean standardised casual FEV1 than either general bakers or dough makers. Thus oven handlers appear to have a greater risk of developing respiratory allergy and airflow obstruction than bakers in other occupational categories.

Adult↗
PubMed1984

Bronchioloalveolar carcinoma arising in longstanding lung cysts.

Two adults, both non-smokers, with large peripheral lung cysts, which were of long standing (12 and nine years), were found to have well differentiated mucus secreting adenocarcinomas with a bronchioloalveolar growth pattern associated with the cysts. Lobectomy is likely to have been curative in one of the cases and earlier surgery might have been so in the other. The fact that many of the reported carcinomas associated with lung cysts have developed at an early age, as well as some histological features, suggests that the association is not coincidental; and early surgery for lung cysts is therefore recommended.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1984

Lung function in diffuse interstitial lung disease of unknown cause.

To examine the role of lung function tests in diagnosis and management of patients with diffuse interstitial lung disease (DILD) we measured total lung capacity (TLC), gas transfer (Tl), lung distensibility and arterial saturation (SaO2) and ventilation during progressive exercise in 24 patients with DILD including 18 with biopsy confirmation. Tl was decreased in all patients, in 21/24 there was progressive hypoxia with exercise, in 12/24 TLC was greater than 80% predicted and in 6/18 lung distensibility was normal. Tl and the change of SaO2 with work output during exercise were highly correlated (r = -0.65, p less than 0.001). In serial studies, the change of SaO2 with work output altered most with clinical improvement or deterioration. The clinical course and response to treatment was not related to a particular pattern of abnormal function. These results and those of previous studies indicate that in DILD the most sensitive index of abnormal parenchymal function is Tl, that lung volumes and distensibility may be normal so that the term "restrictive lung disease" can be misleading, that the fall of SaO2 with work output and Tl are the most sensitive parameters for assessing severity and following the course of the disease and that lung function alone does not predict outcome.

Adult↗
PubMed1984

Mechanical properties of the lung in diffuse interstitial lung disease.

To define the mechanical properties of the lungs in diffuse interstitial lung disease (DILD) the static deflation volume-pressure (VP) and maximum expiratory flow-volume characteristics were measured in 18 patients with DILD including 14 with biopsy confirmation. Elastic recoil, defined by the position of the VP curve, was increased in 12, normal in four and decreased in two patients. The distensibility of inflatable lung, defined by the constant K of a single exponential fitted to the VP data, was decreased in 10 of the 12 with increased recoil and increased in the two with decreased recoil. Those with a normal or increased pulmonary distensibility smoked more than those with decreased distensibility (p less than 0.05). Maximum expiratory flow rates (MEFR) were decreased at any elastic recoil pressure in 12 patients; when corrected for lung size MEFR were decreased in seven patients, six of whom were smokers. These results show that in DILD a decreased pulmonary distensibility is common but not invariable, that an increased elastic recoil reflects both loss of lung units and decreased distensibility of inflatable units and that an increased flow resistance is common. Co-existent emphysema could explain a normal or increased pulmonary distensibility in DILD. The increased flow resistance is due in part to fibrosis and loss of lung units with functional loss of the attendant airways. Decreased MEFR, despite correction for lung size, in seven subjects suggests that structural narrowing of airways, due to cigarette smoking and/or bronchiolar involvement by the disease, also contributes to an increased flow resistance in some patients with DILD.

Airway Resistance↗