A cohort of Indigenous Australian women and their children through pregnancy and beyond: the Gomeroi gaaynggal study.

Indigenous Australians have high rates of chronic diseases, the causes of which are complex and include social and environmental determinants. Early experiences in utero may also predispose to later-life disease development. The Gomeroi gaaynggal study was established to explore intrauterine origins of renal disease, diabetes and growth in order to inform the development of health programmes for Indigenous Australian women and children. Pregnant women are recruited from antenatal clinics in Tamworth, Newcastle and Walgett, New South Wales, Australia, by Indigenous research assistants. Measures are collected at three time points in pregnancy and from women and their children at up to eight time points in the child's first 5 years. Measures of fetal renal development and function include ultrasound and biochemical biomarkers. Dietary intake, infant feeding and anthropometric measurements are collected. Standardized procedures and validated tools are used where available. Since 2010 the study has recruited over 230 women, and retained 66 postpartum. Recruitment is ongoing, and Gomeroi gaaynggal is currently the largest Indigenous pregnancy-through-early-childhood cohort internationally. Baseline median gestational age was 39.1 weeks (31.5-43.2, n=110), median birth weight was 3180 g (910-5430 g, n=110). Over one third (39.3%) of infants were admitted to special care or neonatal nursery. Nearly half of mothers (47.5%) reported tobacco smoking during pregnancy. Results of the study will contribute to knowledge about origins of chronic disease in Indigenous Australians and nutrition and growth of women and their offspring during pregnancy and postpartum. Study strengths include employment and capacity-building of Indigenous staff and the complementary ArtsHealth programme.

Serological evidence of Helicobacter pylori infection in UK South Asian and European populations: implications for gastric cancer and coronary heart disease.

OBJECTIVES: To describe the prevalence of serological evidence of infection with Helicobacter pylori among people of South Asian and European ethnic origins and to assess its association with prevalent coronary heart disease (CHD). METHODS: We used a quantitative method to compare IgG antibodies to H. pylori in a population sample of 300 South Asians and 302 Europeans in Newcastle upon Tyne, UK. RESULTS: For men and women, respectively, H. pylori IgG (95% confidence interval) was 16.7 microg/ml (13.9, 20.2) and 11.3 (9.4, 13.5) among Europeans and 11.6 (9.8, 13.7) and 14.3 (12.1, 16.9) among South Asians. Levels were higher in older participants and in those of lower socioeconomic status. The ratio of geometric mean IgG, (95% confidence interval) adjusted for age, sex and socioeconomic status, in those with and without CHD was 1.02 (0.49, 2.11) among Europeans and 1.79 (1.01, 3.17) among South Asians. Antibodies against staphylococcal enterotoxins A and B were higher among South Asians than Europeans. CONCLUSIONS: The prevalence of H. pylori infection among UK South Asians does not reflect that of their countries of origin, nor their lower prevalence of gastric cancer. The association with CHD in South Asians requires corroboration in other studies.

Cytokine release of whole blood from adult female donors challenged with mistletoe lectin-1 standardised mistletoe extract and E. coli endotoxin or phytohaemagglutinin (PHA).

Cytokine (TNF, alpha, interleukin-6) release of whole blood from healthy donors was challenged with mistletoe extract standardised for mistletoe lectin-1 (sML) and control substances (E. coli endotoxin; phytohaemagglutinin). The rationale of this investigation was non-proven warnings that pro-inflammatory cytokines induce by the application of standardised mistletoe lectins may induce tumor cell proliferation. These investigations provided evidence that non-cytotoxic concentrations of sML did not induced enhanced TNFa or interleukin-6 secretion compared to non-challenged control cells. Cytotoxic concentrations of sML, however, induced significantly higher cytokine levels than the control, obviously due to non-physiological stimuli. Immunomodulation with clinically relevant, low-dose sML incubation did not induce proinflammatory cytokine secretion in vitro.

The role of bacterial toxins in sudden infant death syndrome (SIDS).

There is increasing evidence for the involvement of bacterial toxins in some cases of sudden infant death syndrome (SIDS), particularly the pyrogenic toxins of Staphylococcus aureus. This had led to the hypothesis that some SIDS deaths are due to induction of inflammatory mediators by infectious agents or their products during a period in which the infant is unable to control these normally protective responses. The genetic, developmental and environmental risk factors identified for SIDS are assessed in relation to frequency or density of mucosal colonisation by toxigenic bacteria and their effects on induction and control of inflammatory responses to the toxins.

Why is smoking a risk factor for sudden infant death syndrome?

Smoking is a major risk factor for both Sudden Infant Death Syndrome (SIDS) and respiratory tract infections. Such infections, both viral and bacterial, also increase the SIDS risk. This study investigated the effect of cigarette smoke at two stages of infection: 1) mucosal surface colonization; 2) induction and control of inflammatory responses. For colonization, RSV or influenza A infected cells bound several bacterial species in significantly higher numbers due to increased expression of host cell antigens. Buccal epithelial cells from smokers bound significantly more bacteria. For Staphylococcus aureus, this was associated with increased tar levels. Some SIDS deaths have been proposed to result from high levels of pro-inflammatory mediators elicited by infection and/or cigarette smoke during a developmental period when infants are less able to control inflammatory responses. Inflammatory reponses were compared between blood samples from smokers (n = 42) and non-smokers (n = 60) stimulated with TSST-1 or LPS. Non-smokers had significantly higher IL-6 (P = 0.011), IFN (P = 0.003) and IL-10 (P = 0.000) baseline levels. Non-smokers had higher IFN (P = 0.008) and IL-1 (P = 0.001, 0.007) responses to LPS and higher IL-10 responses to TSST-1 (P < 0.05) and LPS (P < 0.000). This study highlights that smoking increases the SIDS risk by greater susceptibility to viral and bacterial infections and enhanced bacterial binding after passive coating of mucosal surfaces with smoke components. In animal models, IL-10 reduced the lethal effect of staphylococcal toxins. In this study, smokers had lower IL-10 responses toTSST-1 and LPS. Dose response effects of cigarette smoke exposure needs to be established in relation to inflammatory response control and infantile infections.

Evidence for a genetic component in sudden infant death syndrome.

There is increasing evidence that inflammatory responses have been elicited in some Sudden Infant Death Syndrome (SIDS) infants and that these responses are under genetic control. The objective of this study was to investigate the hypothesis that the cytokine responses of SIDS parents (n = 41) differed significantly from control donors (n = 61). Blood samples were stimulated with the staphylococcal toxin TSST-1 and LPS from Eschericia coli and assessed for production of TNF, IL-1, IL-6, IFN and IL-10. In response toTSST-1 (P < 0.02) and LPS (P < 0.002), SIDS parents produced higher levels of IL-1 than the controls. SIDS parents produced higher levels of IFN in response to TSST-1 compared to LPS (P < 0.001) although in response to LPS, the IFN (P = 0.0008) and IL-6 (P < 0.0002) responses of the SIDS parents were lower than those of the controls. For TNF and IL-10, there was little difference between the two groups unless the effect of smoking was considered. As part of this work, a small pilot genotyping study was carried out using DNA from SIDS parents (n = 10), control donors (n = 10) and Bangladeshi subjects (n = 10). An IFN polymorphism (3/3) was found in 40%,15.4% and 0% of donors respectively. Staphylococcal toxins have been identified in SIDS infants therefore this study highlights the importance of assessing IL-1 levels. Determination of cytokine polymorphisms and consideration of interactions between these and environmental factors such as smoking in high, average and low risk ethnic groups will assist in establishing the contribution of these factors to an infant's susceptibility to SIDS.

Application of standardized mistletoe extracts augment immune response and down regulates metastatic organ colonization in murine models.

The immunomodulatory and antimetastatic activity of standardized aqueous mistletoe extracts from plants grown on fir trees (ME-A) and pine trees (ME-P) were evaluated in BALB/c-mice. Regular subcutaneous (s.c.) and intraperitoneal (i.p.) applications (three times per week for 14 consecutive days; 5 and 50 microg per injection and mouse) upregulated thymus weight and peripheral blood leukocyte counts in tumor bearing mice. To check the influence of ME-A and ME-P treatment on growth of experimental metastases, RAW 117 H 10 lymphosarcoma cells and L-1 sarcoma cells were intravenously inoculated into BALB/c-mice to establish liver and lung colonization. ME-A and ME-P were regularly administered starting 24 h after tumor cell challenge. Organ colonization was investigated on day 14 after tumor cell inoculation and demonstrated statistically significant (P<0.05) reductions of experimental liver and lung metastases for ME-A and ME-P treated mice.

Phenotypic and genotypic approaches to characterization of isolates of Neisseria meningitidis from patients and their close family contacts.

Characterization of isolates of Neisseria meningitidis obtained from patients with meningococcal disease or from pharyngeal swabs of asymptomatic carriers can be achieved by several approaches which provide different levels of discrimination. A total of 45 gram negative, oxidase-positive diplococcus strains isolated from 15 individuals with meningococcal disease and 30 of their family contacts were examined by three approaches: serological typing, multilocus enzyme electrophoresis (MLEE), and multilocus sequence typing (MLST). For 10 of the 15 patient and contact groups, all of the isolates were confirmed as meningococci, and the bacteria obtained from the patients and contacts, including their mother or principal caregiver in the case of children, were indistinguishable by all three methods. In the remaining five groups the isolates from the patients were distinct from those recovered from the contacts, and in three examples, in two separate groups, the contacts were shown by MLST to be carrying strains of Neisseria lactamica. The data obtained from the three techniques were consistent, although complete serological typing was possible for only a minority of isolates. Both MLEE and MLST established the genetic relationships of the isolates and identified members of known hypervirulent lineages, but MLST was faster than MLEE and had the additional advantages that it could be performed on noninfective material distributed by mail and that the results from different laboratories could be compared via the internet (http://mlst.zoo.ox.ac.uk).

Quantitative assessment of IgG antibodies to Helicobacter pylori and outcome of ischaemic heart disease.

Criticisms of serological studies on Helicobacter pylori and ischaemic heart disease (IHD) include: undiagnosed heart disease in live controls; no assessment of severity or outcome of IHD; and qualitative not quantitative measurements of IgG to the bacteria. The aim was to assess quantitatively IgG levels specific for H. pylori (ng ml(-1)) among patients who survived a myocardial infarction (MI) with those who died of IHD. Sera were from four groups: (1) men who survived one MI; (2) men matched for age and socioeconomic background to group 1; (3) individuals who died suddenly of IHD; (4) accidental deaths matched for age and sex to group 3. Levels of IgG to H. pylori increased with age (P<0.005) but were not associated with smoking or socioeconomic groups. There was a correlation between IgG to the bacteria and decreasing socioeconomic levels only among group 1 (P<0.01). IgG levels were higher for subjects who died of heart disease (median=151 ng ml(-1)) compared with survivors (median=88 ng ml(-1)) (P=0.034) and higher for survivors compared with their controls (median=58 ng ml(-1)) (P=0.039). Future serological studies of H. pylori in relation to IHD should be quantitative and severity of disease considered in analyses.

Increased inflammatory responses of persons of blood group O to Helicobacter pylori.

Persons of blood group O are at increased risk of peptic ulcers. Enhanced binding of Helicobacter pylori to epithelial cells of persons of blood group O has been demonstrated. Release of interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha by human leukocytes from 40 donors (10 from each ABO blood group) was measured after incubation in vitro with outer membrane protein preparations of H. pylori. Isolates DU (from a patient with a duodenal ulcer), GC (from a patient with gastric cancer), NE (from a patient with normal endoscopic findings), and NCTC 11637 bound in significantly higher numbers to group O leukocytes. Bacterial binding correlated with release of IL-6 and TNF-alpha but not of IL-10. Group O cells released significantly more IL-6 in response to DU, NE, and NCTC 11637, and the cells released more TNF-alpha in response to DU and NCTC 11637. Increased density of colonization of epithelial cells and higher inflammatory responses to H. pylori of persons of blood group O might contribute to increased susceptibility to peptic ulceration.

Bactericidal activity of a monocytic cell line (THP-1) against common respiratory tract bacterial pathogens is depressed after infection with respiratory syncytial virus.

Non-typable Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and respiratory syncytial virus (RSV) are commonly isolated from patients during the course of chronic obstructive pulmonary disease (COPD). Earlier studies found that virus infection enhanced binding of bacterial respiratory pathogens to epithelial cells in vitro. The objective of the present study was to assess the effect of RSV infection of a human monocytic cell line on bactericidal activity and cytokine production in response to these bacterial respiratory pathogens. The effect of RSV infection on binding, uptake and intracellular killing of bacteria by a human monocytic leukaemia cell line, THP-1, was assessed. Cell culture supernates were examined with a mouse fibroblast cell assay for tumour necrosis factor-alpha (TNF-alpha) bioactivity. Expression of CD14, CD11a, CD18, CD15 and CD29 on uninfected and RSV-infected THP-1 cells was assessed by flow cytometry in relation to differences in bacterial binding. RSV infection of THP-1 cells significantly decreased their ability to bind and kill bacteria. Compared with uninfected cells, fewer bacteria bound to RSV-infected THP-1 cells and the surface antigens that have been reported to bind bacteria were expressed at lower levels on RSV-infected cells. RSV-infected cells incubated with bacteria exhibited less TNF-alpha bioactivity than uninfected cell incubated with bacteria. The results elucidate some of the mechanisms involved in the increased susceptibility of virus-infected patients to secondary bacterial infection. Reduced bacterial killing by virus-infected monocytes might contribute to reduced clearance of bacteria from the respiratory tract and damage elicited by the bacteria or cytokine response in COPD patients.

The role of infection in sudden infant death syndrome.

Studies on the potential role of infectious agents in sudden infant death syndrome (SIDS) have been published over the years in a variety of journals. The aim of this special issue of FEMS Immunology and Medical Microbiology is to bring together a group of the most recent studies from Europe, Australia and Canada which cover epidemiology and laboratory studies examining hypotheses relating to infection and inflammation in SIDS. The articles in this issue examine evidence for the involvement of specific micro-organisms in SIDS and the problems relating to experimental studies on infection in relation to the underlying pathology of these deaths. There is an update on the evidence for the common bacterial hypothesis proposed in 1987 examining risk factors identified in epidemiological studies, particularly how the prone sleeping position could affect bacterial colonisation or induction of toxins. Evidence for induction of inflammatory responses in SIDS infants is reviewed and the relation of these responses to mechanisms proposed as causes of death assessed. Factors found to be associated with reduction of the risk of SIDS (breast feeding and immunisation) are examined in relation to some of the toxigenic bacteria implicated in these deaths. Finally, the high incidence of SIDS in some ethnic groups is examined as a potential model to investigate the contributions of genetic, environmental and cultural differences to susceptibility of infants not only to SIDS but to serious respiratory tract infections.

Toxigenic bacteria and sudden infant death syndrome (SIDS): nasopharyngeal flora during the first year of life.

Many developmental and environmental risk factors for sudden infant death syndrome (SIDS) are similar to those for susceptibility to respiratory tract infection, and toxigenic bacteria have been implicated in some SIDS cases. We assessed nasopharyngeal flora of healthy infants in relation to risk factors to determine which species best lit the mathematical model proposed for the common bacterial toxin hypothesis and if these findings complemented results obtained from SIDS cases which occurred during the period of the survey. Longitudinal studies were carried out between April 1993 and March 1996 on 253 healthy infants and their mothers. 150 from a multiply deprived area, 103 from an affluent area. Concurrent SIDS infants (37) were screened for nasopharyngeal flora. Among healthy infants < or = 3 months of age, the predominant isolate was Staphylococcus aureus 57% compared with 86% for SIDS infants in that age range (P< 0.02). There were significant associations between isolation of different species from both mother and baby but no association between isolation of any species with: area of residence: parental smoking habits; breast or bottle feeding; symptoms of viral infection: seasonality. We conclude that S. aureus fits the mathematical model for SIDS. Both staphylococci and/or their toxins were identified in a significant proportion of SIDS cases. Isolation of staphylococci from healthy infants was associated with the 2-4-month age range, a risk factor consistently found in all epidemiological studies of SIDS. This might reflect the developmental stage in which 80-90% of infants express the Lewis(a) antigen which we have shown to be one of the receptors for S. aureus.

Sudden infant death syndrome, virus infections and cytokines.

Many epidemiological risk factors identified for sudden infant death syndrome (SIDS) suggest a viral aetiology, e.g. exposure to cigarette smoke and winter peak, mild respiratory symptoms. Virus infections and bacterial toxins induce cytokine activity and it has been suggested that uncontrolled inflammatory mediators could be involved in some cases of SIDS. The aim of this review was to assess the evidence for virus infection in SIDS and to examine those findings in relation to individual variations in cytokine responses and various pathophysiological mechanisms proposed for SIDS such as sleep derangement, hypoxia, cardiac arrhythmia, vascular hypotonicity and hypoglycaemia.

Detection of pyrogenic toxins of Staphylococcus aureus in sudden infant death syndrome.

It has been suggested that pyrogenic toxins of Staphylococcus aureus are involved in the series of events leading to some cases of sudden infant death syndrome (SIDS). The objectives of the study were to screen tissues from SIDS infants for pyrogenic toxins and to compare incidence of identification of these toxins among these infants from different countries. An enzyme-linked immunosorbent assay (ELISA) and a flow cytometry method were used to screen body fluids and frozen or formalin-fixed tissues for pyrogenic toxins of S. aureus, toxic shock syndrome toxin 1 (TSST), staphylococcal enterotoxins A (SEA), B (SEB), and C1 (SEC). Toxins were identified in tissues of 33/62 (53%) SIDS infants from three different countries: Scotland (10/ 19, 56%); France (7/13, 55%); Australia (16/30, 53%). In the Australian series, toxins were identified in only 3/19 (16%) non-SIDS deaths (chi2 = 5.42, P < 0.02). The flow cytometry method was useful for toxin detection in both frozen and fixed tissues, but ELISA was suitable only for frozen tissues or those fixed for less than 12 months. Identification of pyrogenic toxins in > 50% of SIDS infants from three different countries indicated further investigation into the role the toxins play in cot deaths might result in development of additional measures to reduce further the incidence of these infant deaths.

The effect of prone posture on nasal temperature in children in relation to induction of staphylococcal toxins implicated in sudden infant death syndrome.

The incidence of sudden infant death syndrome (SIDS) has declined in response to campaigns discouraging the prone sleeping position. Recent work suggests some SIDS death may be in response to bacterial toxins produced in the upper airway. A minimal temperature of 37 degrees C is required for induction of the pyrogenic toxins of Staphylococcus aureus identified in many SIDS infants. This aim of this study was to test the hypothesis that the prone position raises the temperature of the upper airways in children. A pilot study of 10 children (aged 3-8) and a main study of 30 children were carried out. Nasal septal temperatures were measured with an infra-red thermometer with the subjects in upright and prone positions under controlled conditions of ambient temperature and humidity. In both the pilot study and main study, nasal temperatures in the prone position were significantly higher (P < 0.01) Five subjects' prone readings were 37 degrees C or higher. These findings suggest that lying prone raises the upper airway surface temperature towards that required for toxin production. This could be one means by which the prone sleeping position contributes to the risk of SIDS.

The protective effect of breast feeding in relation to sudden infant death syndrome (SIDS): I. The effect of human milk and infant formula preparations on binding of toxigenic Staphylococcus aureus to epithelial cells.

Epidemiological studies indicate that breast-fed infants are at a decreased risk of sudden infant death syndrome (SIDS) compared to formula-fed infants. Increasing evidence suggests that infectious agents might be involved in some of these deaths, in particular bacteria which colonise mucosal surfaces and produce superantigenic toxins. One species implicated in recent studies of SIDS infants is Staphylococcus aureus. We tested the hypothesis that in comparison to infant formula, human milk might be a better inhibitor of binding of S. aureus to epithelial cells. In this study, two protocols were used for the binding assays which were assessed by flow cytometry: the in vitro method in which bacteria were treated with milk or formula, washed and added to epithelial cells; and a method more closely reflecting the competitive interactions in vivo in which cells, bacteria, and milk or infant formula were added at the same time. With the in vivo method, breast milk caused enhancement of bacterial binding to cells whilst infant formula caused inhibition; however, for the in vitro method, both human milk and infant formula caused consistent enhancement of binding. Flow cytometry and light microscopy studies indicated that the enhancement was due to the formation of bacterial aggregates. Human milk and infant formula preparations were also compared for components (antibodies or oligosaccharides) that could inhibit binding of S. aureus using the in vitro method. Human milk contained both IgA and IgG. Neither human milk nor infant formula contained oligosaccharides reactive with the Ulex europaeus lectin but both contained components that bound monoclonal antibodies to Lewis(a) and Lewis(b) antigens which can act as receptors for S. aureus. With both methods, synthetic Lewis(a) and Lewis(b) inhibited S. aureus binding in a dose-dependent manner. With human milk, however, the only component which showed a significant correlation with inhibition of binding was the IgA specific for the staphylococcal surface component that binds Lewis(a). Both human milk and infant formula contain components which could potentially inhibit bacterial binding but only breast milk contains the IgA specific for the bacterial adhesin that binds Lewis(a). Studies using the in vivo method suggest that protection associated with breast feeding in relation to SIDS could be due mainly to the formation of bacterial aggregates. The studies have implications for further research into constituents of infant formula.

The protective effect of breast feeding in relation to sudden infant death syndrome (SIDS): II. The effect of human milk and infant formula preparations on binding of Clostridium perfringens to epithelial cells.

Breast feeding is known to protect an infant against gastrointestinal pathogens and epidemiological studies indicate that compared to breast fed infants, formula fed infants are at a greater risk of dying from sudden infant death syndrome (SIDS). Many SIDS infants have symptoms of gastrointestinal infections prior to death and one gastrointestinal pathogen associated with SIDS is Clostridium perfringens. Studies have found that a significantly higher number of formula fed SIDS infants have C perfringens and its enterotoxin in their faeces compared to breast fed infants. The aim of the study was to compare the effects of human milk and infant formula on binding of C perfringens to epithelial cells. Two protocols were used to assess the effect of human milk and infant formula to inhibit binding of C perfringens to epithelial cells. Binding was assessed by flow cytometry. For the in vivo protocol which more closely represents interactions on the mucosal surface, breast milk enhanced bacterial binding but infant formula caused inhibition of binding; however for the in vitro method, both human milk and infant formula resulted in consistent enhancement of binding. Flow cytometry studies indicated that enhancement of binding was due to the formation of bacterial aggregates. Lewis(a) and Lewis(b) antigens, found in both breast milk and infant formula, inhibited C. perfringens binding in a dose dependent manner. The Lewis(a) and Lewis(b) antigens in human milk and infant formula can inhibit C. perfringens binding to epithelial cells. While infant formula reduced binding of C. perfringens to epithelial cells in the experiments carried out with the in vivo protocol, the protective effects of breast feeding in relation to colonisation with C. perfringens are more likely to be due to formation of bacterial aggregates. These findings have implications for improving infant formula preparations.