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Biomedical subjects

B J Hutchcroft

Publications and source records attributed to B J Hutchcroft.

11 recordsLinked to original sources
PubMed1998

Randomised placebo-controlled crossover trial on effect of inactivated influenza vaccine on pulmonary function in asthma.

BACKGROUND: Despite current recommendations, many people with asthma do not receive annual vaccination against influenza, partly because of concern that vaccine may trigger exacerbations. Colds can trigger exacerbations, which may be mistaken for vaccine-related adverse events. We undertook a double-blind placebo-controlled multicentre crossover study to assess the safety of influenza vaccine in patients with asthma, with allowance for the occurrence of colds. METHODS: We studied 262 patients, aged 18-75 years, who recorded daily peak expiratory flow (PEF), respiratory symptoms, medication, medical consultations, and hospital admissions for 2 weeks before the first injection and until 2 weeks after the second injection. Order of injection (vaccine and placebo) was assigned randomly. There was an interval of 2 weeks between injections. The main outcome measure was an exacerbation of asthma within 72 h of injection (defined as a fall in PEF of >20%). FINDINGS: Among 255 participants with paired data, 11 recorded a fall in PEF of more than 20% after vaccine compared with three after placebo (McNemar's test p=0.06); a fall of more than 30% was recorded by eight after vaccine compared with none after placebo (binomial test p=0.008). However, when participants with colds were excluded, there was no significant difference in the numbers with falls of more than 20% between vaccine and placebo (six vs three; binomial test p=0.51), although the difference for PEF decreases of more than 30% approached significance (five vs none; binomial test, p=0.06). This association was confined to first-time vaccinees. INTERPRETATION: Our findings indicate that pulmonary-function abnormalities may occur as a complication of influenza vaccination. However, the risk of pulmonary complications is very small and outweighed by the benefits of vaccination.

Adult↗
PubMed1990

Occupational asthma and specific IgE to a diazonium salt intermediate used in the polymer industry.

This study describes sensitization to a diazonium salt intermediate, diazonium tetrafluoroborate (DTFB), produced during the manufacture of a fluorine polymer precursor. Most of the workers exposed to DTFB powder complained of respiratory and mucosal irritation. However, some of these individuals had symptoms typical of occupational asthma. Clinical and immunologic studies, including bronchial provocation testing and specific IgE measurements, were performed on two individuals with asthmatic symptoms associated with exposure to DTFB. These studies confirmed a diagnosis of occupational asthma. In an investigation of 43 other exposed workers in two separate factories handling the diazonium compound, specific IgE antibodies to DTFB-human serum albumin conjugate were found in 20% of individuals. There was a good correlation between specific IgE and exposure-related respiratory symptoms, which suggests an IgE-mediated pathogenesis. DTFB-human serum albumin conjugates were characterized by electrophoretic techniques, and it was found that conjugates prepared at pH 10 elicited optimum IgE binding in RAST. In vitro cross-linking of albumin by DTFB was demonstrated but had no effect on RAST binding. Our findings on the effect of pH and polymerization on IgE binding support proposed mechanisms for in vivo conjugation and provide information on the antigenic determinants important in IgE recognition of hapten-carrier protein conjugates.

Antibody Formation↗
PubMed1980

The role of calcium in the generation of intracellular SRS-A in passively sensitized human lung challenged with antigen.

Calcium deprivation inhibits the formation and subsequent release of SRS-A as well as histamine from passively sensitized human lung fragments challenged with antigen. Antimycin A inhibits the release of histamine and SRS-A in a dose dependant fashion, while causing a mild inhibition of SRS-A formation throughout the dose range studied. These data suggest that the influx of calcium is the critical event for the generation of SRS-A within the cell.

Animals↗
PubMed1980

Short and long latency skin sensitizing antibody in passive cutaneous anaphylaxis in the monkey.

In some allergic sera, 2-hr PCA responses can be due to IgE class antibody. In other sera where 2-hr PCA responses are not seen, removal of the IgG fracton allows expression of this 2-hr latency PCA response, suggesting an initial competition for binding sites between IgG and IgE, or that IgG can act as a blocking antibody, preventing antigen from reaching the cell-bound IgE.

Absorption↗
PubMed1979

The effects of H1 and H2 receptor antagonism on the response of monkey skin to intradermal histamine, reverse-type anaphylaxis, and passive cutaneous anaphylaxis.

The effects of H1 and H2 receptor anatagonists on models of allergic reactions in monkey skin have been studied. Intradermal histamine is markedly inhibited by H1 receptor antagonists but not by H2 receptor antagonists in the doses used. However, the combination of both receptor antagonists gives greater inhibition than that seen with H1 receptor blockade alone. Reverse-type anaphylaxis is also markedly inhibited by H1 but not H2 receptor antagonists. Passive cutaneous anaphylaxis (PCA) is likewise inhibited by H1 receptor antagonism, but not by H2 receptor antagonism. The combination of the two inhibitors leads to a complete inhibition of this PCA response. The data suggest that the addition of an H2 receptor antagonist may potentiate the effect of H1 blockade alone.

Anaphylaxis↗
PubMed1978

Levels of complement components during allergen-induced asthma.

The levels of circulating complement components C3 and C4, total haemolytic complement, CH50, as well as evidence of complement activation, have been studied in peripheral blood samples during allergen-induced asthma. No evidence of activation of the complement system was detected in these studies.

Allergens↗
PubMed1975

Cystic fibrosis--immunological reactions to A. fumigatus and common allergens.

Immunological studies of forty-three patients with cystic fibrosis showed that positive prick tests to at least one common allergen were obtained in 70%, to multiple allergens in 28% and to A. fumigatus in 50%. Specific IgE antibodies against these allergens were found in the appropriate subjects. In spite of this evidence of type 1, IgE, sensitization none of the patients had a history of infantile eczema. Intracutaneous tests with A. fumigatus extract gave types 1 and 3 reactions in sixteen patients (37%), only seven of whom were among the sixteen (37%) who gave positive precipitin tests. Raised levels of total serum IgG and IgA were found as compared with healthy controls and asthmatic subjects. No differences were found in total serum IgM and IgD levels. The high incidence of allergy to A. fumigatus in cystic fibrosis is confirmed.

Aspergillosis↗