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Biomedical subjects

M X Fitzgerald

Publications and source records attributed to M X Fitzgerald.

At least 19 recordsLinked to original sources
PubMed1994

Serum IgA and IgG subclasses during treatment for acute respiratory exacerbation in cystic fibrosis: analysis of patients colonised with mucoid or non-mucoid strains of pseudomonas aeruginosa.

Patients with cystic fibrosis (CF) have a high prevalence of Pseudomonas aeruginosa infection which causes chronic infection of the mucosal surfaces of the lung. This results in recurrent immune stimulation and hypergammaglobulinemia. The present study examines the levels of circulating Ig classes, IgG and IgA subclasses in 13 adult patients with CF during acute pulmonary infection and post-exacerbation. Total serum IgG levels were raised in the patients during infection and post-treatment when compared to the normal range (mean +/- SEM: 17.21 +/- 1.4 g/l vs 16.45 +/- 1.5 g/l respectively; normal range 8-16 g/l). In contrast, total IgM (2.6 +/- 0.26 vs 2.69 +/- 2.74 g/l; normal range 0.6-2.8 g/l) and IgA levels (2.5 +/- 0.52 vs 2.41 +/- 0.48 g/l; normal range 0.5-4 g/l) remained unchanged when examined during all stages of the disease. Of the 13 patients studied, 69%, 39% and 31% had IgG, IgM and IgA levels respectively raised above the normal range values. The mean levels of individual IgG subclasses examined in this group of patients revealed values within the normal ranges, however IgG2 and IgG3 were increased in 31% and 46% of patients. Individual IgG3 levels fell in 77% (10/13) and IgG4 in 62% (8/13) of the patients post-exacerbation. With regard to IgA subclasses, significant reduction in the IgA1 levels were observed post treatment (3687 +/- 539 mg/l vs 2713 +/- 498 mg/l, p < 0.01). In contrast, IgA2 levels were increased from 279 +/- 49 mg/l to 421 +/- 69 mg/l, although statistical significance was not reached. Upon antibiotic treatment for infection, the findings in this study show that IgA1 which is susceptible to bacterial proteases is reduced with a concommitant increase in the protease resistant IgA2 subclass. Moreover, patients colonised with non-mucoid strains of P. aeroginosa had higher total IgA levels due to the raised IgA1 subclass whereas they had lower IgG levels due to low IgG2 and IgG4 subclasses.

Acute Disease↗
PubMed1993

Spontaneous in vitro production of rheumatoid factor during infectious exacerbations of cystic fibrosis: correlation with circulating immune complex levels.

Rheumatoid factor (RF) production has been demonstrated during infections, including infectious exacerbations of cystic fibrosis (CF). The aim of this study was to evaluate the relationship of RF production to infection, and examine the mechanisms involved. Serial peripheral blood mononuclear cell (PBMC) cultures with measurement of spontaneous production of IgM RF, IgA RF, total IgM and IgA, and measurement of serum levels of immune complexes were carried out during exacerbations of CF. The percentage of B cells expressing CD5 was examined in a second cohort of acutely infected CF patients, and related to IgM RF production. IgM RF production was significantly elevated during acute infection compared with convalescence (P < 0.05), stable CF subjects (P < 0.005) and normal controls (P < 0.05). IgM RF production did not correlate with total IgM production in the majority of patients, but was closely related to circulating immune complex levels in 8/10 subjects. IgA RF production did not increase significantly during infection, and did not correlate with total IgA or IgM RF production, or with circulating immune complex levels. CD5+ B cells were not increased in the CF group, and the percentage of CD5+ B cells did not correlate with IgM RF synthesis. These observations suggest that RF production during infection is specifically induced, possibly by immune complex autoimmunization, and is not simply the result of polyclonal B cell activation. Different patterns of IgM RF and IgA RF synthesis suggest different mechanisms of induction.

Acute Disease↗
PubMed1993

alpha 1-Proteinase inhibitor, elastase activity, and lung disease severity in cystic fibrosis.

The potential role of neutrophil elastase in exacerbating pulmonary infection and tissue damage in cystic fibrosis (CF) has led to proposals for treatment of lung disease in CF with the elastase inhibitor, alpha 1-proteinase inhibitor (alpha 1PI). Reports that alpha 1PI is inactivated in the CF lung suggest that the effectiveness of alpha 1PI therapy depends on the quantity of elastase present and the extent of alpha 1PI inactivation, both of which are expected to vary with disease severity. In this study we assessed the elastase-alpha 1PI profile in sputum and plasma from CF patients with various degrees of pulmonary involvement. Levels of active elastase in sputum samples increased with severity of pulmonary disease (F ratio = 5.63, p < 0.01), as did sputum levels of alpha 1PI (F ratio = 4.88, p < 0.01). A positive correlation was observed between sputum levels of active elastase and alpha 1PI (r = 0.68, p < 0.005). Plasma alpha 1PI levels were also elevated in CF patients compared with control subjects (p < 0.005), indicating a compensatory increase in plasma and sputum levels of alpha 1PI in response to increased elastase load. Molar levels of total immunogenic neutrophil elastase were, on average, 12 times higher than alpha 1PI in CF sputum. These results suggest that the major contributor to the elevated levels of active elastase observed in the CF lung is an increase in elastase release rather than inactivation of alpha 1PI.

Adolescent↗
PubMed1992

Biliary complications of cystic fibrosis.

One hundred and four adult patients with cystic fibrosis were evaluated for the presence of liver disease as defined by abnormal liver function tests of six months' duration, histological evidence of fibrosis or cirrhosis, or the presence of portal hypertension, or both. Twenty patients fulfilled these criteria and were evaluated further for the presence of biliary tract abnormalities with biliary scintigraphy using 99Tc diisopropylphenyl-carboxymethyl iminodiacetic acid (DISIDA) and endoscopic retrograde cholangiography. Clearance of 99Tc DISIDA from the liver and biliary tree was diminished at 45 (E45) and 60 (E60) minutes in the patients with liver disease compared with those without liver disease; E45 = 37.8% and 65.8%, p less than 0.01; E60 = 48.2% and 77.5%, p less than 0.01 respectively. Serial analogue images of the extrahepatic biliary tree were consistent with common bile duct obstruction with retention of DISIDA and tapering of the common bile duct in seven of 18 patients with and two of 10 patients without liver disease. Endoscopic retrograde cholangiography showed changes consistent with sclerosing cholangitis, with beading and stricturing of the intrahepatic ducts in 12 of the 14 patients. In all 14 patients, including those in whom biliary scintigraphy had suggested obstruction, no abnormality of the common bile duct was identified. These results indicate that abnormalities of the bile ducts in patients with cystic fibrosis related liver disease are confined to the intrahepatic biliary tree and that common bile duct strictures do not contribute to either the progression or development of liver disease in these patients.

Adolescent↗
PubMed1991

A chest radiograph scoring system in adult cystic fibrosis: correlation with pulmonary function.

The Birmingham scoring system for chest radiographs was assessed in 40 adult cystic fibrosis patients, with particular reference to correlation with pulmonary function values. Forty 'initial' and forty 'follow-up' chest radiographs were scored. The mean initial age of the group was 17.5 +/- 5.0 years, and the mean age at follow-up was 23.3 +/- 5.3 years. The cross-sectional radiographic score correlated significantly with the values of three commonly measured, pulmonary function parameters (r = 0.65, 0.67, 0.58, P less than 0.0001). There was a significant correlation (r = 0.64, P less than 0.0001), between the change in radiographic score, and the change in percent predicted forced vital capacity (FVC%). There was a less significant correlation (r = 0.45, P less than 0.006) between the change in radiographic score and the change in per cent predicted forced expiratory volume in one second (FEV1%). We conclude that the Birmingham radiographic scoring system is suitable for quantitative radiological evaluation in adult cystic fibrosis.

Adolescent↗
PubMed1991

Obstructive sleep apnea following topical oropharyngeal anesthesia in loud snorers.

Previous studies support the presence of an upper airway reflex mechanism that contributes to the maintenance of upper airway patency during sleep. We investigated the possibility that interference with this reflex mechanism contributes to the development of obstructive sleep apnea. Eight otherwise asymptomatic snorers (seven male and one female), age 39 +/- 5.3 yr (mean +/- SEM), underwent overnight sleep studies on three successive nights. An acclimatization night was followed by two study nights randomly assigned to control (C) and oropharyngeal anesthesia (OPA). On the OPA night topical anesthesia was induced using 10% lidocaine spray and 0.25% bupivacaine gargle. A saline placebo was used on night C. All subjects slept well on both study nights (mean sleep duration was 6.2 h on both study nights), and sleep stage distribution was similar on both nights. Obstructive apneas and hypopneas (OAH) rose from 114 +/- 43 during C to 170 +/- 49 during OPA (p less than 0.02). Central apneas and hypopneas (CAH) were unchanged between the two nights (8 +/- 4.9 versus 7 +/- 3). The duration of OAH was similar on both study nights (20 +/- 1.9 s during C versus 20 +/- 1.5 s during OPA). The frequency of movement arousals terminating OAH tended to be higher during OPA (7 +/- 2.9/h) than during C (3 +/- 0.7); P = NS. The frequency of oxyhemoglobin desaturations was also higher during OPA (5 +/- 2.1/h) than during C (3 +/- 1.4), p less than 0.07.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗