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D F Mallon

Publications and source records attributed to D F Mallon.

8 recordsLinked to original sources
PubMed2001

High prevalence of coeliac disease in a population-based study from Western Australia: a case for screening?

OBJECTIVES: To determine the prevalence of coeliac disease in an Australian rural community. DESIGN: Retrospective analysis of stored serum samples from 3,011 random subjects from the Busselton Health Study. IgA antiendomysial antibodies (AEA) were detected by indirect immunofluorescence, and subjects testing positive were contacted and offered small-bowel biopsy. MAIN OUTCOME MEASURES: Prevalence of AEA positivity and biopsy-proven coeliac disease in the community with reference to the proportion of symptomatic to asymptomatic patients. RESULTS: 10 of 3,011 subjects were AEA positive. One subject had died, one subject could not be traced and one refused small-bowel biopsy. All subjects with detectable AEA who consented to biopsy had pathological changes consistent with coeliac disease. The prevalence of newly diagnosed biopsyproven coeliac disease is 7 in 3,011 (1 in 430). Two further subjects had a diagnosis of coeliac disease before this study. When all AEA-positive patients and those previously diagnosed are included, the prevalence is 12/3,011 (1 in 251). There was a significant clustering of cases in the 30-50-years age range, with 10/12 (83%; 95% CI, 52%-98%) aged between 30 and 50 years, compared with 1,092/3,011 (36%; 95% CI, 35%-38%) of the total population (P<0.03). Of the eight AEA-positive subjects who could be contacted, four had symptoms consistent with coeliac disease and four were asymptomatic. Three subjects were iron-deficient, four subjects had first-degree relatives with coeliac disease and one subject had type 1 diabetes mellitus. CONCLUSIONS: The prevalence of coeliac disease is high in a rural Australian community. Most patients are undiagnosed, and asymptomatic.

Adult↗
PubMed1999

Monocyte-derived dendritic cells as a model for the study of HIV-1 infection: productive infection and phenotypic changes during culture in human serum.

Dendritic cells (DC) have been implicated in the initial selection for macrophage-tropic HIV-1 during transmission and in the generation of high-level virus replication during interactions with CD4 T cells. The role of DC as viral reservoirs and the extent of productive infection is unclear, but the ability to generate large numbers of DC from blood monocytes has produced a tractable model for study of DC-HIV-1 interactions. When cultured in granulocyte-macrophage colony stimulating factor and IL-4, sorted CD14+ monocytes rapidly lost phagocytic function for both 93 nm and 977 nm latex particles and developed the surface markers and function of DC. After 7 days, when returned to medium containing human serum without cytokines, some monocyte-derived dendritic cells (MDDC) became adherent, but retained the costimulatory markers CD80 and CD86 and continued to express CD83 and CD40. The MDDC stimulated allogeneic CD4 T cells, did not express new macrophage markers and remained non-phagocytic. With or without TNF-alpha, MDDC generated in cytokines were infected by macrophage and T cell-tropic virus and produced higher reverse transcriptase levels than did the autologous monocyte-derived macrophages (MDM). When added to T cells, the infected MDDC were able to infect T cells with a wider range of viral isolates than were MDM.

Antigens, CD↗
PubMed1997

Ethanol-induced anaphylaxis following ingestion of overripe rock melon, Cucumis melo.

BACKGROUND: Anaphylactic reactions to ethanol are rare with only seven cases reported in the literature. All previous cases have occurred following ingestion of alcoholic beverages or food to which an alcoholic beverage has been added. To date there are no cases in the literature of ethanol-induced anaphylaxis caused by the accumulation of endogenous ethanol in overripe fruit. METHODS: We report a patient with ethanol-induced anaphylaxis who developed anaphylaxis following ingestion of overripe, but not fresh rock melon (Cucumis melo). The patient is a 24-year-old, previously well woman who experienced five episodes of acute anaphylaxis following ingestion of various alcoholic beverages and, on one occasion, following ingestion of overripe rock melon to which no ethanol was added. Ethanol-induced anaphylaxis was confirmed on blinded challenge; however, challenge with freshly prepared rock melon was negative. The patient declined further challenges. CONCLUSION: Ingestion of overripe fruits may cause anaphylaxis in patients with ethanol-induced anaphylaxis. These patients should therefore, be advised to avoid ingestion of overripe fruits.

Adult↗
PubMed1992

Exposure to blood borne infections in health care workers.

OBJECTIVE: To determine the incidence and nature of occupational exposures to blood and body fluids in health care workers. DESIGN: 332 reports of occupational exposure were analysed and are presented. SETTING: A major teaching hospital. PARTICIPANTS: All staff at Royal Perth Hospital who reported an occupational exposure to blood or body fluids to the Department of Clinical Immunology between 1 January 1990 and 31 August 1991. OUTCOME MEASURES: The rate of reported occupational exposure according to staff category, nature of exposure, HIV status of source patient, activity at the time of exposure and compliance with infection control measures. RESULTS: 332 reports from 323 health care workers were received, giving an overall incidence of 6.1 per 100 full time equivalent (FTE) years. Nursing staff (9.4/100 FTE years) and medical staff (9.0/100 FTE years) reported exposure more frequently than housekeeping staff (2.5/100 FTE years) or paramedical staff (2.3/100 FTE years) (P < 0.001). The rate of exposure to HIV antibody positive patients was only 0.24/100 FTE years. Needlestick or other blood contaminated sharps injuries accounted for 83.4% (277/332) of reports and failure to observe universal precautions for 34.0% of reports. Insertion and operation of parenteral lines (24%) and performing operations (15.4%) were the activities most often associated with occupational exposure. No occupationally acquired infections were observed. Despite the immediate availability of zidovudine, acceptance by health care workers with high risk occupational exposure was low (18.8%). CONCLUSIONS: Occupational exposure to blood and body fluids is common among health care workers but most exposures confer a low risk of blood borne infection. The introduction of an occupational exposure assessment program has many benefits, including optimal management of injuries and acquisition of data on infection control measures, and may protect health care institutions from false claims for compensation.

Blood↗
PubMed1991

Severe late postsplenectomy infection.

In all, 1490 patients underwent splenectomy in Western Australia between 1971 and 1983, giving 7825 person years exposure. Thirty-three patients developed severe late postsplenectomy infection (septicaemia, meningitis or pneumococcal pneumonia requiring hospitalization) and three developed overwhelming postsplenectomy infection. The incidence and mortality rates of severe late postsplenectomy infection were 0.42 and 0.08 per 100 person years exposure respectively and for overwhelming postsplenectomy infection the incidence and mortality rates were 0.04 per 100 person years exposure. There were 628 splenectomies after trauma, giving 3922 person years exposure. Eight patients developed severe late postsplenectomy infection of whom one had overwhelming postsplenectomy infection. Following trauma, the incidence of severe late postsplenectomy infection was 0.21 per 100 person years exposure, with the incidence and mortality rates of overwhelming postsplenectomy infection being 0.03 per 100 person years exposure. Patients undergoing splenectomy have a 12.6-fold increased risk of developing late septicaemia compared with the general population. Splenectomy following trauma gives an 8.6-fold increased risk of late septicaemia. The majority of severe late postsplenectomy infections did not occur within the first 2 years and 42 per cent of severe late postsplenectomy infections occurred greater than 5 years after splenectomy. The low incidence of severe late postsplenectomy infection and overwhelming postsplenectomy infection makes statistical evaluation of the effectiveness of prophylactic antibiotics, vaccination and splenic repair most difficult.

Adolescent↗
PubMedDate not supplied

Fine structural recognition specificities of IgE antibodies distinguishing amoxicilloyl and amoxicillanyl determinants in allergic subjects.

IgE antibodies in the sera of subjects allergic to beta-lactam antibiotics detect a spectrum of specificities ranging from side-chain groups to an entire penicillin or cephalosporin molecule. In addition to such structural heterogeneity of allergenic determinants, IgE antibodies in the sera of different allergic subjects show heterogeneous recognition responses. Detailed immunochemical studies were carried out on the sera of penicillin-allergic subjects that showed selective and unexpected reactions with the frequently prescribed penicillin, amoxicillin. Antibodies from one subject reacted only with the amoxicilloyl determinant while IgE from another subject showed multiple reactivity with penicilloyl and penicillanyl determinants of different penicillins but not with the amoxicilloyl determinant. Quantitative hapten inhibition studies revealed that the combining sites of the former antibodies were complementary to amoxicillin in a form that permits binding to the hydroxyaminobenzyl side-chain and the thiazolidine ring carboxyl. These conditions are satisfied with the drug in the '-oyl' but not in the '-anyl' form which involves linkage through the 2-carboxyl of the thiazolidine ring. With the second serum, adsorption studies showed that the wide-ranging reactivity of IgE was due to a single population of antibodies that detected a common specificity on the different penicillins. Combining site studies revealed clear recognition of the benzyl portion of the side-chain of benzylpenicilloyl, benzylpenicillanyl, ampicilloyl, ampicillanyl and amoxicillanyl determinants when free antibody access to the side-chain was possible but little or no recognition of the ring hydroxyl of amoxicillin. Such uninhibited access may not occur, however, when amoxicillin is conjugated in the '-oyl' form since opening the beta-lactam ring allows increased flexibility and rotation of the molecule and the possibility of close association of the hydroxyaminobenzyl side-chain of amoxicillin with the linked peptide carrier. In such close steric association, H-bonding involving the ring hydroxyl and amino acids of the carrier may prevent antibody access to the side-chain region of the amoxicilloyl determinant.

Adsorption↗