Mitochondrial haplogroups and control region polymorphisms in age-related macular degeneration: a case-control study

BACKGROUND

Onset and development of the multifactorial disease age-related macular degeneration (AMD) are highly interrelated with mitochondrial functions such as energy production and free radical turnover. Mitochondrial dysfunction and overproduction of reactive oxygen species may contribute to destruction of the retinal pigment epithelium, retinal atrophy and choroidal neovascularization, leading to AMD. Consequently, polymorphisms of the mitochondrial genome (mtDNA) are postulated to be susceptibility factors for this disease. Previous studies from Australia and the United States detected associations of mitochondrial haplogroups with AMD. The aim of the present study was to test these associations in Middle European Caucasians.

METHODOLOGY/PRINCIPAL FINDINGS

Mitochondrial haplogroups (combinations of mtDNA polymorphisms) and mitochondrial CR polymorphisms were analyzed in 200 patients with wet AMD (choroidal neovascularization, CNV), in 66 patients with dry AMD, and in 385 controls from Austria by means of multiplex primer extension analysis and sequencing, respectively. In patients with CNV, haplogroup H was found to be significantly less frequent compared to controls, and haplogroup J showed a trend toward a higher frequency compared to controls. Five CR polymorphisms were found to differ significantly in the two study populations compared to controls, and all, except one (T152C), are linked to those haplogroups.

CONCLUSIONS/SIGNIFICANCE

It can be concluded that haplogroup J is a risk factor for AMD, whereas haplogroup H seems to be protective for AMD.

Mitochondrial haplogroups, control region polymorphisms and malignant melanoma: a study in middle European Caucasians

Background

Because mitochondria play an essential role in energy metabolism, generation of reactive oxygen species (ROS), and apoptosis, sequence variation in the mitochondrial genome has been postulated to be a contributing factor to the etiology of multifactorial age-related diseases, including cancer. The aim of the present study was to compare the frequencies of mitochondrial DNA (mtDNA) haplogroups as well as control region (CR) polymorphisms of patients with malignant melanoma (n = 351) versus those of healthy controls (n = 1598) in Middle Europe.

Methodology and Principal Findings

Using primer extension analysis and DNA sequencing, we identified all nine major European mitochondrial haplogroups and known CR polymorphisms. The frequencies of the major mitochondrial haplogroups did not differ significantly between patients and control subjects, whereas the frequencies of the one another linked CR polymorphisms A16183C, T16189C, C16192T, C16270T and T195C were significantly higher in patients with melanoma compared to the controls. Regarding clinical characteristics of the patient cohort, none of the nine major European haplogroups was associated with either Breslow thickness or distant metastasis. The CR polymorphisms A302CC-insertion and T310C-insertion were significantly associated with mean Breslow thickness, whereas the CR polymorphism T16519C was associated with metastasis.

Conclusions and Significance

Our results suggest that mtDNA variations could be involved in melanoma etiology and pathogenesis, although the functional consequence of CR polymorphisms remains to be elucidated.

The mitochondrial T16189C polymorphism is associated with coronary artery disease in Middle European populations

Background

The pivotal role of mitochondria in energy production and free radical generation suggests that the mitochondrial genome could have an important influence on the expression of multifactorial age related diseases. Substitution of T to C at nucleotide position 16189 in the hypervariable D-loop of the control region (CR) of mitochondrial DNA (mtDNA) has attracted research interest because of its suspected association with various multifactorial diseases. The aim of the present study was to compare the frequency of this polymorphism in the CR of mtDNA in patients with coronary artery disease (CAD, n = 482) and type 2 diabetes mellitus (T2DM, n = 505) from two study centers, with healthy individuals (n = 1481) of Middle European descent in Austria.

Methodology and Principal Findings

CR polymorphisms and the nine major European haplogroups were identified by DNA sequencing and primer extension analysis, respectively. Frequencies and Odds Ratios for the association between cases and controls were calculated. Compared to healthy controls, the prevalence of T16189C was significantly higher in patients with CAD (11.8% vs 21.6%), as well as in patients with T2DM (11.8% vs 19.4%). The association of CAD, but not the one of T2DM, with T16189C remained highly significant after correction for age, sex and body mass index (BMI) and was independent of the two study centers.

Conclusions and Significance

Our results show for the first time a significant association of T16189C with CAD in a Middle European population. As reported in other studies, in patients with T2DM an association with T16189C in individuals of European decent remains questionable.

Mitochondrial DNA haplogroup T is associated with coronary artery disease and diabetic retinopathy: a case control study

Background

There is strong and consistent evidence that oxidative stress is crucially involved in the development of atherosclerotic vascular disease. Overproduction of reactive oxygen species (ROS) in mitochondria is an unifying mechanism that underlies micro- and macrovascular atherosclerotic disease. Given the central role of mitochondria in energy and ROS production, mitochondrial DNA (mtDNA) is an obvious candidate for genetic susceptibility studies on atherosclerotic processes. We therefore examined the association between mtDNA haplogroups and coronary artery disease (CAD) as well as diabetic retinopathy.

Methods

This study of Middle European Caucasians included patients with angiographically documented CAD (n = 487), subjects with type 2 diabetes mellitus with (n = 149) or without (n = 78) diabetic retinopathy and control subjects without clinical manifestations of atherosclerotic disease (n = 1527). MtDNA haplotyping was performed using multiplex PCR and subsequent multiplex primer extension analysis for determination of the major European haplogroups. Haplogroup frequencies of patients were compared to those of control subjects without clinical manifestations of atherosclerotic disease.

Results

Haplogroup T was significantly more prevalent among patients with CAD than among control subjects (14.8% vs 8.3%; p = 0.002). In patients with type 2 diabetes, the presence of diabetic retinopathy was also significantly associated with a higher prevalence of haplogroup T (12.1% vs 5.1%; p = 0.046).

Conclusion

Our data indicate that the mtDNA haplogroup T is associated with CAD and diabetic retinopathy in Middle European Caucasian populations.

Spin currents in diluted magnetic semiconductors

We study zero-bias spin separation in (Cd,Mn)Te/(Cd,Mg)Te diluted magnetic semiconductor structures. The spin current generated by electron gas heating under terahertz radiation is converted into a net electric current by applying an external magnetic field. The experiments show that the spin polarization of the magnetic ion system enhances drastically the conversion process due to giant Zeeman splitting of the conduction band and spin-dependent electron scattering on localized Mn(2+) ions.

The protective effect of farm animal exposure on childhood allergy is modified by NPSR1 polymorphisms

BACKGROUND

Little is known about the asthma candidate gene neuropeptide S receptor 1 (NPSR1) in relation to environmental exposures, but recent evidences suggest its role as an effect modifier.

OBJECTIVES

To explore the interaction between NPSR1 polymorphisms and environmental exposures related to farming lifestyle and to study the in vitro effects of lipopolysaccharide (LPS) stimulation on NPSR1 expression levels.

METHODS

We studied 3113 children from PARSIFAL, a European cross-sectional study on environmental/lifestyle factors and childhood allergy, partly focused on children brought up on a farm. Information on exposures and outcomes was primarily obtained from parental questionnaires. Seven tagging polymorphisms were analysed in a conserved haplotype block of NPSR1. Multivariate logistic regression was used to evaluate a multiplicative model of interaction. NPSR1 protein and messenger RNA (mRNA) levels in monocytes were measured after LPS stimulation by fluorescence activated cell sorting (FACS) and quantitative real-time polymerase chain reaction (PCR).

RESULTS

A strong interaction was seen between current regular contact to farm animals and several NPSR1 polymorphisms, particularly rs323922 and rs324377 (p<0.005), with respect to allergic symptoms. Considering the timing of initiation of such current regular farm animal contact, significant interactions with these and two additional polymorphisms (SNP546333, rs740347) were revealed. In response to LPS, NPSR1-A protein levels in monocytes were upregulated (p = 0.002), as were NPSR1-A mRNA levels (p = 0.02).

CONCLUSIONS

The effect of farm animal contact on the development of allergic symptoms in children is modified by NPSR1 genetic background.

A polymorphism in CD14 modifies the effect of farm milk consumption on allergic diseases and CD14 gene expression

BACKGROUND

Consumption of farm milk in early life is associated with less asthma and allergies.

OBJECTIVE

We hypothesized that genetic variation in the innate immunity receptor CD14 might modify the association between farm milk consumption and asthma and atopy.

METHODS

Questionnaire data, serum IgE levels, and genotypes for 4 single nucleotide polymorphisms in CD14 were assessed in farmers' and nonfarmers' children from 2 European populations (Allergy and Endotoxin study, n = 576; Prevention of Allergy Risk factors for Sensitization in children related to Farming and Anthroposophic Lifestyle study, n = 1539). In a subsample (n = 222) CD14 gene expression was measured in peripheral blood leukocytes. The effects of farm milk and CD14 genotypes on asthma, allergies, and CD14 expression and their interactions were investigated.

RESULTS

We found a significant interaction between genetic variation in CD14/-1721 and farm milk consumption. Adjusted odds ratios for the association between farm milk and asthma varied between the genotypes: AA, 0.18 (95% CI, 0.07-0.47); AG, 0.47 (95% CI, 0.26-0.86); and GG, 0.98 (95% CI, 0.46-2.08). Similar patterns were observed for symptoms of allergic rhinoconjunctivitis and pollen sensitization. CD14/-1721 also modified the association between farm milk and CD14 gene expression (adjusted geometric means ratios: AA, 1.61 (95% CI, 0.98-2.66); AG, 1.11 (95% CI, 0.71-1.72); and GG, 0.76 (95% CI, 0.39-1.48).

CONCLUSION

The protective effect of farm milk consumption on allergic diseases is stronger in children carrying the A allele in CD14/-1721 than in children homozygous for the G allele. This might be mediated through farm milk-induced upregulated CD14 gene expression.

CLINICAL IMPLICATIONS

Our results support the hypothesis that the inverse association between farm milk consumption and allergic diseases is mediated by CD14-activated innate immune mechanisms.

[Pulmonary nocardiosis with trimethoprime/sulphamethoxazole-resistant Nocardia paucivorans in a patient with no signs of immunosuppression]

This is so far the first published case report of a Nocardia paucivorans infection in an immunocompetent patient. A 54-year-old farmer was hospitalised with a history of coughing and fever for a period of five months. There was no indicator of either primary of secondary immunodeficiency in the prior medical history. A chest X-ray showed pneumonic infiltrates in the right middle und lower lobes, which progressed despite of antibiotic therapy with macrolides. A transbronchial biopsy revealed unspecific granulomatous inflammation of soft tissues. N. paucivorans - grew in cultures of sputum, bronchoalveolar lavage, and transbronchial biopsy. Oral antibiotic therapy was started with trimethoprime-sulphamethoxazole (TMP/SMX) and amoxicillin plus clavulanic acid. Susceptibility testing revealed high level resistance to TMP/SMX, which was consequently replaced by ciprofloxacin. Six months later, infiltrates had completely resolved and the patient did not report any residual clinical symptoms. The present case showed once again that nocardiosis is not limited to patients with immunodeficiencies. However, conservative combination therapy with oral antibiotics seems to be sufficiently effective for nocardiosis in the immunocompetent patient. For cases of suspected nocardiosis, a step-wise, risk-based diagnostic and therapeutic procedure is proposed.

Association between exposure to farming, allergies and genetic variation in CARD4/NOD1

BACKGROUND

Caspase recruitment domain protein (CARD) 4 has been recently identified as an intracellular pattern recognition receptor that interacts with muropeptides found in common Gram-negative bacteria. We therefore aimed to explore whether the previously observed inverse association between exposure to microbial products and asthma and allergies in childhood is modified by genetic variation in CARD4.

METHODS

We genotyped 668 children [mean age 9.3 (SD 1.5) years] enrolled in the cross-sectional ALEX study for seven haplotype tagging single nucleotide polymorphisms in CARD4. We studied the association of asthma, hay fever and allergen-specific serum immunoglobulin E with exposure to a farming environment and with levels of endotoxin and muramic acid measured in house dust samples. We tested whether these associations differed between the genotypes of the polymorphisms under study.

RESULTS

A strong protective effect of a farming environment on allergies was only found in children homozygous for the T allele in CARD4/-21596, but not in children carrying the minor allele (C). Among the former, farmers' children had a significantly lower frequency of sensitization against pollen (5.8%), hay fever (1.7%) and atopic asthma symptoms (1.7%) compared with children not living on a farm (19.4%, 13.0% and 7.6%, P<0.01, <0.01 and <0.05, respectively). Conversely, no significant difference in prevalence of these phenotypes by farming status was found among children with a C allele in CARD4/-21596 (14.3%, 7.1% and 8.0%vs 16.5%, 9.0% and 5.7%, respectively).

CONCLUSION

Polymorphisms in CARD4 significantly modify the protective effect of exposure to a farming environment.

Validation of questions on asthma and wheeze in farming and anthroposophic children

BACKGROUND

In most epidemiological surveys the estimated prevalence of asthma is based on questionnaire responses, which may depend on the individual's perception as well as medical consulting habits in a given population. Therefore, measurement of bronchial hyper-responsiveness as a key feature of asthma has been suggested as an objective parameter for asthma.

OBJECTIVE

The aim of the present study was to validate questionnaire responses on asthma and wheeze against bronchial response to hypertonic saline (HS) (4.5%) in populations previously shown to have a lower prevalence of asthma and allergies: farmers' children and children from anthroposophic families.

METHODS

Children whose parents had completed a written questionnaire in the cross-sectional PARSIFAL-study were drawn from the following four subgroups: 'farm children' (n=183), 'farm reference children' (n=173), 'Steiner schoolchildren' (n=243) and 'Steiner reference children' (n=179). Overall, 319 children with wheeze in the last 12 months and 459 children without wheeze in the last 12 months performed an HS challenge.

RESULTS

Odds ratios, sensitivity, specificity, likelihood ratios and measures of association did not differ significantly between the four subgroups. The correlation between the bronchial response to HS and wheeze and asthma questions was moderate and similar for farm children, farm reference children, Steiner schoolchildren and Steiner reference children (kappa for 'wheeze': 0.25, 0.33, 0.31, 0.35, respectively, P=0.754, kappa for 'doctor's diagnosis of asthma': 0.33, 0.19, 0.33, 032, respectively, P=0.499).

CONCLUSION

The findings from this study suggest that the reliabilitiy of questionnaire responses on asthma and wheeze is comparable between farmers' children, children raised in families with anthroposophic lifestyle and their respective peers.

Opposite effects of CD 14/-260 on serum IgE levels in children raised in different environments

BACKGROUND

Most complex diseases are the result of interactions between polymorphisms in the genome and environmental exposures.

OBJECTIVE

We sought to investigate the previously reported association between a polymorphism in the promoter region of CD 14 (CD 14/-260 C-->T) and serum IgE levels in relation to the environment to which children are exposed.

METHODS

In 624 children living in 2 rural communities in Europe, we compared total and specific serum IgE levels between the genotypes of CD 14/-260 in relation to exposure to animals and in relation to house dust endotoxin.

RESULTS

We found that the C allele of CD 14/-260 was associated with higher levels of both total and specific serum IgE to aeroallergens in children with regular contact with pets, whereas an association in the opposite direction was found in children with regular contact with stable animals. This modifying effect of animal exposure was not explained by levels of house dust endotoxin. However, in children with high levels of house dust endotoxin, the C allele was associated with less specific IgE, independently from animal exposure.

CONCLUSION

Because CD 14 is a pattern recognition receptor for microbial molecules, the results suggest that the type and concentrations of such molecules present in the environment strongly determine the direction of the association between CD 14/-260 and serum markers of atopy.

Exposure to pets, and the association with hay fever, asthma, and atopic sensitization in rural children

BACKGROUND

An increasing number of studies report pet exposure to be associated with lower risk of asthma and allergies. This 'protective pet effect' has been suggested to result from a modified T-helper (Th)2-cell response, or because of increased microbial load in homes where pets are kept. We examined the associations between pet contact and the occurrence of asthma and allergies in children of the rural Allergy and Endotoxin (ALEX) population, taking farm animal contact, endotoxin and cat allergen levels in mattress dust into account.

METHODS

Information about contact with pets and farm animals, asthma and allergy were collected for 812 children by a standardized parents' questionnaire and an interview. Mattress dust endotoxin and cat allergen levels as well as specific IgE and IgG4 antibodies to Fel d1 were determined.

RESULTS

Current contact with dogs was inversely associated with diagnosed hay fever (OR 0.26, 95% CI 0.11-0.57), diagnosed asthma (OR 0.29, 95% CI 0.12-0.71), sensitization to cat allergen (OR 0.48, 95% CI 0.23-0.99) and to grass pollen (OR 0.55, 95% CI 0.33-0.94), but not with increased IgG4 levels. Early and current contact with cats were associated with reduced risk of wheezing (OR 0.48, 95% CI 0.23-1.00, and OR 0.49, 95% CI 0.26-0.92, respectively) and grass pollen sensitization. Adjustment for farm animal contact but not for endotoxin and cat allergen exposure attenuated these associations and the effect of pet was stronger among farmers' children.

CONCLUSION

Although pet exposure was very frequent in this rural population, the inverse relation between current dog contact, asthma and allergy was mostly explained by simultaneously occurring exposure to stable animals or was restricted to farm children. In addition, a subtle form of pet avoidance may contribute to the protective effect of pet.

Hygiene hypothesis and endotoxin: what is the evidence?

PURPOSE OF REVIEW

The hygiene hypothesis has gained strong support over the past few years. Exposure to microbial products in early life could be an underlying factor in this hypothesis, but the mechanisms that lead from a less clean and more crowded environment to a lower prevalence of asthma and allergies are not known. Among the variety of potential microbial molecules that may confer protection against the development of asthma and allergies, endotoxin, a component of Gram-negative bacteria, has incited lively as well as controversial discussions. This review focuses on recent studies on endotoxin and its role in the context of the hygiene hypothesis.

RECENT FINDINGS

Results from cross-sectional surveys, prospective cohorts, and experimental studies in vitro and in rodents suggest that exposure to house dust endotoxin in early life protects from atopic sensitization and IgE-mediated diseases, but is a risk factor for wheezing in infancy.

SUMMARY

Numerous studies have supported the hygiene hypothesis, but whether endotoxin by itself confers the protection or whether it acts as a marker for another environmental exposure is still unclear. The challenge for the future will be to identify those factors that confer the protection proposed by the hygiene hypothesis, and to find strategies to modify the environment without causing harm to susceptible individuals.

Microbial exposure of rural school children, as assessed by levels of N-acetyl-muramic acid in mattress dust, and its association with respiratory health

BACKGROUND

Endotoxin exposure has been shown to be associated with a decreased prevalence of atopic sensitization and symptoms. Yet endotoxin represents only a part of the indoor microbial exposure. Muramic acid, a constituent of peptidoglycan, is present in gram-negative and gram-positive bacteria in the environment and may therefore serve as an additional marker of microbial exposure.

OBJECTIVE

To study the factors determining the level of indoor exposure to muramic acid/peptidoglycan, as well as its potential association with respiratory health.

METHODS

In 553 farm and nonfarm school children from Austria, Switzerland, and Germany, mattress dust muramic acid concentrations were determined, and health was assessed by using IgE measurements and questionnaire information.

RESULTS

The muramic acid concentration was found to be significantly higher in dust from farm children's mattresses than in dust from nonfarm children's mattresses (157 vs 131 ng/mg). Children with higher mattress dust muramic acid concentrations had a significantly lower prevalence of wheezing (odds ratio of highest vs lowest tertile of muramic acid concentration, 0.3; 95% CI, 0.1-0.9), regardless of farming status and endotoxin exposure. The association for asthma was similar, and no association was found with atopic sensitization.

CONCLUSION

Next to endotoxin, muramic acid provides us with an independent marker of microbial exposure. Unlike endotoxin, muramic acid was inversely associated with wheezing rather than with atopic sensitization.

Determinants of endotoxin levels in living environments of farmers' children and their peers from rural areas

BACKGROUND

Lower frequencies of asthma and hayfever have been observed in children with contact to livestock. At school age, the amount of endotoxin measured in the dust of children's mattresses is inversely related to the occurrence of atopic asthma, hayfever and atopic sensitization both in children from farming and non-farming households.

OBJECTIVE

The aim of the present study was to investigate which home and lifestyle characteristics of farm and non-farm families contribute to endotoxin levels measured in different indoor home environments.

METHODS

In the framework of the Allergy and Endotoxin (ALEX) Study, endotoxin was measured in dust samples from the living room floor and the child's mattress of 319 farmers' families and 493 non-farming families, and in settled dust from stables. Endotoxin content of all dust samples was determined by a kinetic Limulus assay (Limulus-Amebocyte-Lysate test). Information about the child's activities on farms, home characteristics and cleaning behaviours was obtained from parental questionnaires.

RESULTS

Endotoxin levels in stables did not predict the amount of endotoxin measured in floors or mattresses. However, a dose-dependent association between the child's activity on the farm and indoor home endotoxin levels was observed, both in farm and non-farm children. In non-farm children pet keeping and the frequency of floor cleaning were additionally associated with endotoxin levels, whereas in farm children parental farm activities, study area, time since last cleaning, the mattress type as well as younger age of the children contributed to increased microbial exposure.

CONCLUSION

These results demonstrate that regular contact to farm animals increases indoor home endotoxin concentrations, both in farm and non-farm children, and might thus explain the protective effect of contact to livestock on atopic outcomes. To assess children's individual exposure to a microbial environment, measures of mattress dust exposure are needed as stable endotoxin concentrations were not associated with indoor home levels.

Toll-like receptor 2 as a major gene for asthma in children of European farmers

BACKGROUND

The finding that the prevalence of asthma and allergies is less frequent in children raised on animal farms has led to the conjecture that exposure to microbial products modifies immune responses. The toll-like receptors (TLRs) represent an evolutionarily conserved family of innate immunity receptors with microbial molecules as ligands.

OBJECTIVES

We reasoned that polymorphisms in genes encoding TLRs might modulate the protective effects observed in farming populations.

METHODS

Farmers' and nonfarmers' children living in rural areas in Austria and Germany and who were enrolled in the cross-sectional ALEX study were genotyped for single nucleotide polymorphisms in the TLR2 and TLR4 genes. The frequencies of asthma, allergic rhinitis, and atopic sensitization were compared between the genotypes in relation to exposure to farming and endotoxin.

RESULTS

Among farmers' children, those carrying a T allele in TLR2/-16934 compared with children with genotype AA were significantly less likely to have a diagnosis of asthma (3% vs 13%, P = .012), current asthma symptoms (3% vs 16%, P = .004), atopic sensitization (14% vs 27%, P = .023), and current hay fever symptoms (3% vs 14%, P = .01). The association between TLR2/-16934 and asthma among children of farmers was independent of atopy. No such association was found among children from the same rural communities but not living on farms.

CONCLUSION

Our results suggest that genetic variation in TLR2 is a major determinant of the susceptibility to asthma and allergies in children of farmers.

Hygiene hypothesis and endotoxin: what is the evidence?

PURPOSE OF REVIEW

The hygiene hypothesis has gained strong support over the past few years. Exposure to microbial products in early life could be an underlying factor in this hypothesis, but the mechanisms that lead from a less clean and more crowded environment to a lower prevalence of asthma and allergies are not known. Among the variety of potential microbial molecules that may confer protection against the development of asthma and allergies, endotoxin, a component of Gram-negative bacteria, has incited lively as well as controversial discussions. This review focuses on recent studies on endotoxin and its role in the context of the hygiene hypothesis.

RECENT FINDINGS

Results from cross-sectional surveys, prospective cohorts, and experimental studies in vitro and in rodents suggest that exposure to house dust endotoxin in early life protects from atopic sensitization and IgE-mediated diseases, but is a risk factor for wheezing in infancy.

SUMMARY

Numerous studies have supported the hygiene hypothesis, but whether endotoxin by itself confers the protection or whether it acts as a marker for another environmental exposure is still unclear. The challenge for the future will be to identify those factors that confer the protection proposed by the hygiene hypothesis, and to find strategies to modify the environment without causing harm to susceptible individuals.

Rethinking Th2 antibody responses and allergic sensitization

Human Th2 cytokines (interleukins 4 and 13) induce co-expression of IgE and IgG4 through sequential switching. The regulation of IgG4 responses and the role of these responses in the pathogenesis of allergy have not been characterized. We are addressing these issues by comparing and contrasting the expression of allergen-specific IgE and IgG4 in a population of European children thoroughly defined for lifestyle, environmental exposures and allergic phenotypes. The current analysis focused exclusively on children from non-farming families (n=493) in order to avoid potential effects of exposure to microbial products abundant in farming environments. We found that allergens induce Th2-mediated IgG4 and/or IgE responses in the majority of the population. Approximately two-thirds of the children had allergen-specific IgG4 but not IgE, only a minority had both IgG4 and IgE, only a few were negative for both, and virtually none had only IgE. The prevalence of asthma and hay fever was dramatically higher in children with high IgG4 and IgE compared to children who only mounted IgG4 or low IgG4 and IgE responses. These results appear to recapitulate different stages of in vivo Th2-dependent sequential switching from IgG4 to IgE. These patterns of Th2-induced antibody responses may warrant a redefinition of the notion of allergen sensitization.

Environmental exposure to endotoxin and its relation to asthma in school-age children

BACKGROUND

In early life, the innate immune system can recognize both viable and nonviable parts of microorganisms. Immune activation may direct the immune response, thus conferring tolerance to allergens such as animal dander or tree and grass pollen.

METHODS

Parents of children who were 6 to 13 years of age and were living in rural areas of Germany, Austria, or Switzerland where there were both farming and nonfarming households completed a standardized questionnaire on asthma and hay fever. Blood samples were obtained from the children and tested for atopic sensitization; peripheral-blood leukocytes were also harvested from the samples for testing. The levels of endotoxin in the bedding used by these children were examined in relation to clinical findings and to the cytokine-production profiles of peripheral-blood leukocytes that had been stimulated with lipopolysaccharide and staphylococcal enterotoxin B. Complete data were available for 812 children.

RESULTS

Endotoxin levels in samples of dust from the child's mattress were inversely related to the occurrence of hay fever, atopic asthma, and atopic sensitization. Nonatopic wheeze was not significantly associated with the endotoxin level. Cytokine production by leukocytes (production of tumor necrosis factor alpha, interferon-gamma, interleukin-10, and interleukin-12) was inversely related to the endotoxin level in the bedding, indicating a marked down-regulation of immune responses in exposed children.

CONCLUSIONS

A subject's environmental exposure to endotoxin may have a crucial role in the development of tolerance to ubiquitous allergens found in natural environments.

Signature lipids and stable carbon isotope analyses of Octopus Spring hyperthermophilic communities compared with those of Aquificales representatives

The molecular and isotopic compositions of lipid biomarkers of cultured Aquificales genera have been used to study the community and trophic structure of the hyperthermophilic pink streamers and vent biofilm from Octopus Spring. Thermocrinis ruber, Thermocrinis sp. strain HI 11/12, Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus, and Aquifex aeolicus all contained glycerol-ether phospholipids as well as acyl glycerides. The n-C(20:1) and cy-C(21) fatty acids dominated all of the Aquificales, while the alkyl glycerol ethers were mainly C(18:0). These Aquificales biomarkers were major constituents of the lipid extracts of two Octopus Spring samples, a biofilm associated with the siliceous vent walls, and the well-known pink streamer community (PSC). Both the biofilm and the PSC contained mono- and dialkyl glycerol ethers in which C(18) and C(20) alkyl groups were prevalent. Phospholipid fatty acids included both the Aquificales n-C(20:1) and cy-C(21), plus a series of iso-branched fatty acids (i-C(15:0) to i-C(21:0)), indicating an additional bacterial component. Biomass and lipids from the PSC were depleted in (13)C relative to source water CO(2) by 10.9 and 17.2 per thousand, respectively. The C(20-21) fatty acids of the PSC were less depleted than the iso-branched fatty acids, 18.4 and 22.6 per thousand, respectively. The biomass of T. ruber grown on CO(2) was depleted in (13)C by only 3.3 per thousand relative to C source. In contrast, biomass was depleted by 19.7 per thousand when formate was the C source. Independent of carbon source, T. ruber lipids were heavier than biomass (+1.3 per thousand). The depletion in the C(20-21) fatty acids from the PSC indicates that Thermocrinis biomass must be similarly depleted and too light to be explained by growth on CO(2). Accordingly, Thermocrinis in the PSC is likely to have utilized formate, presumably generated in the spring source region.

Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey

BACKGROUND

A farming environment protects against development of asthma, hay fever, and atopic sensitisation in children. We aimed to establish whether increased exposure to microbial compounds has to occur early in life to affect maturation of the immune system and thereby reduces risk for development of allergic diseases.

METHODS

We did a cross-sectional survey in rural areas of Austria, Germany, and Switzerland. 2618 (75%) of 3504 parents of 6-13-year-old children completed a standardised questionnaire on asthma, hay fever, and atopic eczema. Children from farming families, and a random sample of non-farmers' children, who gave consent for blood samples to be obtained for measurements of specific serum IgE antibodies to common allergens were invited to participate (n=901).

FINDINGS

Exposure of children younger than 1 year, compared with those aged 1-5 years, to stables and consumption of farm milk was associated with lower frequencies of asthma (1% [3/218] vs 11% [15/138]), hay fever (3% [7] vs 13% [18]), and atopic sensitisation (12% [27] vs 29% [40]). Protection against development of asthma was independent from effect on atopic sensitisation. Continual long-term exposure to stables until age 5 years was associated with the lowest frequencies of asthma (0.8% [1/122]), hay fever (0.8% [1]), and atopic sensitisation (8.2% [10]).

INTERPRETATION

Long-term and early-life exposure to stables and farm milk induces a strong protective effect against development of asthma, hay fever, and atopic sensitisation.

Microbial diversity of the brine-seawater interface of the Kebrit Deep, Red Sea, studied via 16S rRNA gene sequences and cultivation methods

The brine-seawater interface of the Kebrit Deep, northern Red Sea, was investigated for the presence of microorganisms using phylogenetic analysis combined with cultivation methods. Under strictly anaerobic culture conditions, novel halophiles were isolated. The new rod-shaped isolates belong to the halophilic genus Halanaerobium and are the first representatives of the genus obtained from deep-sea, anaerobic brine pools. Within the genus Halanaerobium, they represent new species which grow chemoorganotrophically at NaCl concentrations ranging from 5 to 34%. The cellular fatty acid compositions are consistent with those of other Halanaerobium representatives, showing unusually large amounts of Delta7 and Delta11 16:1 fatty acids. Phylogenetic analysis of the brine-seawater interface sample revealed the presence of various bacterial 16S rRNA gene sequences dominated by cultivated members of the bacterial domain, with the majority affiliated with the genus Halanaerobium. The new Halanaerobium 16S rRNA clone sequences showed the highest similarity (99.9%) to the sequence of isolate KT-8-13 from the Kebrit Deep brine. In this initial survey, our polyphasic approach demonstrates that novel halophiles thrive in the anaerobic, deep-sea brine pool of the Kebrit Deep, Red Sea. They may contribute significantly to the anaerobic degradation of organic matter enriched at the brine-seawater interface.

Austrian children living on a farm have less hay fever, asthma and allergic sensitization

BACKGROUND AND OBJECTIVES

In some studies, the prevalence of hay fever and asthma has been found to be lower in children from rural areas than in children from an urban environment. We hypothesized that living on a farm might be protective against development of allergic sensitization and allergic diseases.

METHODS

In a cross-sectional survey, parents of 2283 children aged 8-10 years from a mostly rural area in Austria answered a standardized questionnaire on allergic diseases and environmental factors. 1137 children performed a skin prick test to seven local allergens.

RESULTS

The prevalence of hay fever (3.1 vs 10.3%, P = 0.0002), asthma (1.1 vs 3.9%, P = 0.017) and a positive skin prick reactivity to at least one of the common local allergens (18.8 vs 32.7%, P = 0. 001) was significantly lower in children living on a farm than in children from a non-farming environment. In a multivariate logistic regression model, adjusting for genetic background, parent education, living and housing conditions and dietary factors did not change the odds ratio for the association of farming and allergic sensitization. Only after including 'regular contact with livestock and poultry' into the model did the odds ratio change significantly (cOR 0.48 95% CI 0.30-0.75 to aOR 0.75 95% CI 0.37-1.52) indicating an association between regular contact with farm animals and reduced risk of atopic sensitization.

CONCLUSION

Possible explanations for the lower prevalence of hay fever, asthma and allergic sensitization in children living on a farm might be the development of immunotolerance or the stimulation of TH1 cells and suppression of TH2 cells by increased exposure of farm children to microbial antigens in the stables or farmhouses.

Lack of a late asthmatic response after hypertonic saline challenge in children

Hypertonic saline challenge has become a standardized method for measuring airway responsiveness. However, there is still uncertainty about the occurrence of a late asthmatic response. Therefore, the present study was designed to assess a possible late asthmatic response after hypertonic saline challenge in children. Twenty-one children with mild to moderate bronchial hyperresponsiveness were studied. On days 1 and 2, forced expiratory volume in one second (FEV1) was measured hourly from 10:00 h to 22:00 h to assess diurnal variation of lung function. On the third study day, a hypertonic saline challenge was performed and FEV1 was measured as on control days. The possibility of a late asthmatic response was tested by comparing FEV1 levels up to 12 h after the challenge on the intervention day to FEV1 levels on control days. In no subjects were the FEV1 values following the challenge found to be considerably below the individual mean of the control days. Furthermore, a nonparametric approach was applied for each child and the population looked into as a whole. Again, no late asthmatic response was detectable. The results of this study suggest that in children with mild to moderate bronchial hyperresponsiveness a late asthmatic response does not occur 4-12 h after a 4.5% saline challenge.

Novel 16S rRNA gene sequences retrieved from highly saline brine sediments of kebrit deep, red Sea

In this study, we report on first 16S rRNA gene sequences from highly saline brine sediments taken at a depth of 1,515 m in the Kebrit Deep, northern Red Sea. Microbial DNA extracted directly from the sediments was subjected to PCR amplification with primers specific for bacterial and archaeal 16S rRNA gene sequences. The PCR products were cloned, and a total of 11 (6 bacterial and 5 archaeal) clone types were determined by restriction endonuclease digestion. Phylogenetic analysis revealed that most of the cloned sequences were unique, showing no close association with sequences of cultivated organisms or sequences derived from environmental samples. The bacterial clone sequences form a novel phylogenetic lineage (KB1 group) that branches between the Aquificales and the Thermotogales. The archaeal clone sequences group within the Euryarchaeota. Some of the sequences cluster with the group II and group III uncultivated archaea sequence clones, while two clone groups form separate branches. Our results suggest that hitherto unknown archaea and bacteria may thrive in highly saline brines of the Red Sea under extreme environmental conditions.

[Prevalence and severity of bronchial asthma, allergic rhinitis and atopic dermatitis in Salzburg school children]

As part of the International Study of Asthma and Allergies in Childhood (ISAAC), the aim of our study was to determine the prevalence and severity of asthma, allergic rhinitis and eczema in Austrian schoolchildren, using an international standardised protocol. A questionnaire concerning symptoms and prior diagnosis of asthma, allergic rhinitis and eczema was completed by the parents of 3581 children aged 6-8 years. 3357 adolescents aged 12-15 years completed a written and video questionnaire at school. We also measured airway responsiveness to 4.5% saline in 519 adolescents selected from 8 randomly chosen schools. The prevalence of "wheezing in the last 12 months" was 9.9% (6-8 yrs) and 11.9% (12-15 yrs), the prevalence of "ever having had a diagnosis of asthma" was 4.4% and 6.3% in the above mentioned age groups. While 80% of the pupils had mild asthma (defined as less than 4 attacks of wheezing in the last year), 13% had moderate (4-12 attacks) and 7% had severe asthma (> 12 attacks). The 12-month prevalence of symptoms of allergic rhinitis was 13.4% (6-8 yrs) and 22.5% (12-15 yrs), a diagnosis of "hayfever at any time" was reported in 8.9% and 20.4%. The prevalence of a chronic rash in the past year was 6.9% (6-8 yrs) and 6.7% (12-15 yrs), while 10.4% and 5%, respectively, had had a diagnosis of "eczema at any time". Among 12- to 15-year-old adolescents in the entire study population (n = 3371), the calculated prevalence of bronchial hyperresponsiveness was 13.7%. The prevalence of asthma symptoms, rhinitis and eczema in Austrian schoolchildren is higher than that estimated so far and similar to other European countries except the UK. Further, the results show that the 12-month prevalence of asthma symptoms is twice as high as the lifetime prevalence of a diagnosis of asthma, suggesting that the condition is frequently underdiagnosed.

[Clinical follow-up of an epidemiologic study on asthma and allergies in childhood]

The results of a recent epidemiological study in Salzburg (Austria) showed that the prevalence of bronchial hyperresponsiveness (BHR) to hypertonic saline (HS) was 13.7% in schoolchildren aged 12-15 years. In the same study the prevalence of wheezing in the last 12 months was 11.9% and asthma had been diagnosed in 6.3%. To audit the relevance of these results and to offer medical treatment to children with newly diagnosed asthma, we invited all children who had had a positive bronchial provocation test (n = 99) or an abnormal lung function (defined as an FEV1 < 80% of the predicted value; n = 33) for clinical investigation. Seventy-five out of 99 children with BHR and 27/33 with an FEV1 < 80% of the predicted value attended the Respiratory Laboratory and a paediatric pulmonologist assessed the diagnosis on the basis of respiratory symptoms, physical examination and lung function test. In 26/53 children with asthma, the diagnosis was unknown. Although most children had mild asthma and normal lung function, half of these children had reduced physical activity. In 27/53 children with asthma, the diagnosis had already been known but, according to the specialist, had not been adequately treated. In 21/27 children with an FEV1 < 80% of the predicted value, this finding was clinically not relevant. The audit of the epidemiological study supported the assumption that asthma might be underdiagnosed and undertreated in our population.

Prevalence of bronchial hyperresponsiveness to 4.5% saline and its relation to asthma and allergy symptoms in Austrian children

The prevalence of asthma in school children has been reported to have increased, with wide variations between countries. To allow comparison of prevalence data, objective markers of asthma should be measured. Therefore, we assessed the prevalence of bronchial hyperresponsiveness (BHR) to hypertonic saline and its relation to asthma and allergy symptoms in 507 Austrian school children, aged 12-15 yrs in a cross-sectional, community based survey. These children were selected from 3,371 children who had answered a self-administered written questionnaire on asthma, hay fever, eczema and environmental factors. The prevalence of BHR to hypertonic saline was 14% and the majority (70%) of the children had mild BHR. The prevalence of wheeze in the last 12 months was 12% and of a diagnostic label of asthma was 6%. Fifty three per cent of the children with symptoms in the last 12 months and a diagnostic label of asthma had BHR, and 33% of those with symptoms in the last 12 months regardless of a diagnostic label of asthma showed a positive response to hypertonic saline. Atopic dermatitis, a diagnostic label of asthma, night cough apart from colds, wheeze in the past 12 months (but not "former wheeze") and male gender were significantly associated with increased response to 4.5% saline in the final logistic regression model. These results show that the prevalence of asthma symptoms in the last 12 months and the prevalence of bronchial hyperresponsiveness to hypertonic saline are twice that of a diagnosis of asthma and that asthma might be underdiagnosed in the present population. The response to hypertonic saline is most strongly associated with current asthma and allergy symptoms. A combination of a "diagnostic label of asthma" and "asthma symptoms in the last 12 months" might best reflect "current asthma" in epidemiological studies in this population.

Comparative in vitro activity of the new oxacephem antibiotic, flomoxef (6315-S)

The in vitro activity of flomoxef (6315-S) was determined and compared to that of different cephalosporins against 787 clinical isolates of staphylococci, Enterobacteriaceae and anaerobes. Flomoxef is similar in activity to latamoxef and cefotaxime against Enterobacteriaceae, slightly more active than cephalothin and cefamandole against oxacillin-sensitive strains of Staphylococcus aureus and minimally less active than cefamandole against oxacillin-resistant strains. Flomoxef showed similar or better activity than latamoxef and cefoxitin against most of the anaerobic species of medical importance.

Septicemia caused by Kingella kingae

A case of Kingella kingae septicemia following acute gastroenteritis is described. Intravenous antibiotic treatment with mezlocillin and tobramycin led to rapid and sustained recovery. The infection with Kingella kingae may have been food-borne.