Dual-comb optical parametric oscillator in the mid-infrared based on a single free-running cavity

We demonstrate a free-running single-cavity dual-comb optical parametric oscillator (OPO) pumped by a single-cavity dual-comb solid-state laser. The OPO ring cavity contains a single periodically-poled MgO-doped LiNbO₃ (PPLN) crystal. Each idler beam has more than 245-mW average power at 3550 nm and 3579 nm center wavelengths (bandwidth 130 nm). The signal beams are simultaneously outcoupled with more than 220 mW per beam at 1499 nm and 1496 nm center wavelength. The nominal repetition rate is 80 MHz, while the repetition rate difference is tunable and set to 34 Hz. To evaluate the feasibility of using this type of source for dual-comb applications, we characterize the noise and coherence properties of the OPO signal beams. We find ultra-low relative intensity noise (RIN) below -158 dBc/Hz at offset frequencies above 1 MHz. A heterodyne beat note measurement with a continuous wave (cw) laser is performed to determine the linewidth of a radio-frequency (RF) comb line. We find a full-width half-maximum (FWHM) linewidth of around 400 Hz. Moreover, the interferometric measurement between the two signal beams reveals a surprising property: the center of the corresponding RF spectrum is always near zero frequency, even when tuning the pump repetition rate difference or the OPO cavity length. We explain this effect theoretically and discuss its implications for generating stable low-noise idler combs suitable for high-sensitivity mid-infrared dual-comb spectroscopy (DCS).

Spatially-multiplexed tunable dual-comb optical parametric oscillator at 250 MHz

We demonstrate a spatially-multiplexed dual-comb 250-MHz OPO from a single linear cavity. The adjustable repetition-rate difference is 4.1 kHz. Each idler comb has >200-mW average power at 3.5 μm with 30 nm bandwidth. The OPO is wavelength-tunable from 1.36 μm to 1.7 μm and 2.9 μm to 4.17 μm. © 2022 The Author(s)

51-W average power, 169-fs pulses from an ultrafast non-collinear optical parametric oscillator

We present a high power optical parametric oscillator (OPO) synchronously pumped by the second-harmonic of a modelocked 1030-nm thin-disk laser (TDL) oscillator. The OPO delivers an average power of 51.1 W around degeneracy (1030 nm) with a 10.2-MHz repetition-rate. After extra-cavity dispersion compensation using dispersive mirrors, we obtain a pulse duration of 169 fs, which is 4.6× shorter than the TDL pulse duration of 770 fs. The TDL has 250 W average power, which is converted to 215 W at the second-harmonic. Hence, the OPO exhibits a high photon conversion efficiency of 47% (ratio of signal photons to 515-nm pump photons). Moreover, the OPO generates a peak power of 26.2 MW, which is very similar to the 28.0-MW peak power of the TDL. To facilitate continuous tuning around degeneracy and convenient extraction of the pump and idler beams, the OPO is operated in a noncollinear configuration. A linear cavity configuration was chosen since it offers easy alignment and straightforward cavity length tuning. To the best of our knowledge, this source has the highest average power generated by any ultrafast OPO, and the shortest pulse duration for any >5-W OPO. This result is an important step to adding wavelength tunability to high power Yb-based laser sources without the complexity of either laser or parametric amplifier systems.

Associations between serum 25-hydroxyvitamin D and bone turnover markers in a population based sample of German children

Severe vitamin D deficiency is known to cause rickets, however epidemiological studies and RCTs did not reveal conclusive associations for other parameters of bone health. In our study, we aimed to investigate the association between serum levels of 25(OH) vitamin D and bone turnover markers in a population-based sample of children. 25(OH)D, calcium (Ca), osteocalcin (OC), and β-Crosslaps (β-CTx) were measured in 2798 ten-year-old children from the German birth cohorts GINIplus and LISAplus. Linear regression was used to determine the association between bone turnover markers and 25(OH)D levels. 25(OH)D, OC, and β-CTx showed a clear seasonal variation. A 10 nmol/l increase in 25(OH)D was significantly associated with a 10.5 ng/l decrease (p < 0.001) in β-CTx after adjustment for design, sex, fasting status, time of blood drawn, BMI, growth rate, and detectable testosterone/estradiol. For OC alone no significant association with 25(OH)D was observed, whereas the β-CTx-to-OC ratio was inversely associated with 25(OH)D (−1.7% change, p < 0.001). When stratifying the analyses by serum calcium levels, associations were stronger in children with Ca levels below the median. This study in school-aged children showed a seasonal variation of 25(OH)D and the bone turnover markers OC and β-CTx. Furthermore a negative association between 25(OH)D and the bone resorption marker β-CTx was observed.

German national consensus recommendations on nutrition and lifestyle in pregnancy by the 'Healthy Start - Young Family Network'

Diet and physical activity before and during pregnancy affect short- and long-term health of mother and child. The energy needs at the end of pregnancy increase only by about 10% compared to nonpregnant women. An excessive energy intake is undesirable since maternal overweight and excessive weight gain can increase the risks for a high birth weight and later child overweight and diabetes. Maternal weight at the beginning of pregnancy is especially important for pregnancy outcome and child health. Women should strive to achieve normal weight already before pregnancy. Regular physical activity can contribute to a healthy weight and to the health of pregnant women. The need for certain nutrients increases more than energy requirements. Before and during pregnancy, foods with a high content of essential nutrients should be preferentially selected. Supplements should include folic acid and iodine, iron (in case of suboptimal iron stores), the ω-3 fatty acid docosahexaenoic acid (in case of infrequent consumption of ocean fish) and vitamin D (in case of decreased sun exposure and decreased endogenous vitamin D synthesis). Pregnant women should not smoke and not stay in rooms where others smoke or have smoked before (passive smoking). Alcohol consumption should be avoided, since alcohol can harm unborn children.

Epidemiology of urticaria in infants and young children in Germany--results from the German LISAplus and GINIplus Birth Cohort Studies

BACKGROUND

Although urticaria is considered one of the most frequent skin diseases, reliable epidemiologic data are scarce.

OBJECTIVE

To evaluate the incidence and cumulative prevalence of urticaria in infants and children up to age of 10, to characterize the relationship of specific IgE levels (food and inhalative allergens) with urticaria, and to monitor the joint occurrence of urticaria with other diseases, such as eczema, asthma, and hay fever.

METHODS

The study population consisted of two prospective birth cohort studies: the LISAplus and GINIplus studies. Information on physician-diagnosed urticaria, asthma, eczema, or hay fever was collected using self-administered questionnaires completed by the parents. Blood samples were drawn, and specific immunoglobulin E measured at 2 (only LISAplus), 6 and 10 yr of age.

RESULTS

The incidence of urticaria was approximately 1% per year of age. The cumulative prevalence of urticaria in children up to the age of 10 yr was 14.5% for boys and 16.2% for girls. Cumulative prevalence of urticaria at the age of ten was significantly (p < 0.05) associated with allergic sensitization to peanut, soy, and wheat flour, but not with inhalant allergens. Both a parental history of atopy/urticaria and the children's diagnosis of asthma, eczema, and hay fever were strongly related (p < 0.0001) to the occurrence of urticaria.

CONCLUSIONS

Urticaria is a frequent event during childhood, with highest incidence in infants and preschool children. Comorbidity with atopic disease is high.

Respiratory health in children, and indoor exposure to (1,3)-β-D-glucan, EPS mould components and endotoxin

For a long time, exposure to mould and dampness-derived microbial components was considered a risk factor for the development of respiratory diseases and symptoms. Some recent studies suggested that early childhood exposure to mould components, such as (1,3)-β-D-glucan and extracellular polysaccharides (EPSs), may protect children from developing allergy. We investigated the association of exposure to (1,3)-β-D-glucan, EPS and endotoxin with asthma and allergies in 6-yr-old children. This investigation was the follow-up to a nested case-control study among three European birth cohorts. Children from two ongoing birth cohort studies performed in Germany (n = 358) and one in the Netherlands (n = 338) were selected. Levels of (1,3)-β-D-glucan, EPS and endotoxin were measured in settled house dust sampled from children's mattresses and living-room floors when the children were, on average, 5 yrs of age. At the age of 6 yrs, health outcome information was available for 678 children. In the two German subsets, domestic EPS and endotoxin exposure from children's mattresses were significantly negatively associated with physician-diagnosed asthma (OR per interquartile range increase 0.60 (95% CI 0.39-0.92) and 0.55 (95% CI 0.31-0.97), respectively). In addition, EPS exposure was inversely related to physician-diagnosed allergic rhinitis (OR 0.50, 95% CI 0.31-0.81). For the Dutch population, no associations were observed between exposure to microbial agents and respiratory health outcomes. We found inverse associations between domestic exposure to EPS and endotoxin from children's mattresses, and doctor-diagnosed asthma and rhinitis in German, but not in Dutch, school children. The reasons for the differences between countries are not clear.

Common variants in FCER1A influence total serum IgE levels from cord blood up to six years of life

BACKGROUND

In a recent genome wide scan, a functional promoter variant (rs2251746) in the gene encoding the alpha chain of the high affinity receptor for immunoglobulin E (IgE) (FCER1A) was identified as major determinant of serum IgE levels.

OBJECTIVE

The aim of this study was to investigate the role of rs2251746 on total IgE levels measured at different stages of life from birth (cord blood) up to the age of 6 and to evaluate its interaction with the environmental influences in two German birth cohorts.

METHOD

Data from two German birth cohorts were analysed (n = 1043 for the LISA cohort and n = 1842 for the GINI cohort). In the studies, total serum IgE was measured from cord blood, and blood samples taken at the age of 2/3 and 6 years. In a subgroup of the LISA study, house dust samples were collected at age of 3 months and the amount of endotoxin was determined. Random effect models were used to analyse the longitudinal health outcomes.

RESULTS

In the two cohorts, the heterozygote and the rare homozygote of rs2251746 was consistently associated with lower total IgE levels from birth up to the age of 6 years with an allele-dose effect (P < 0.02 for blood samples taken at each time point in both cohorts). No interaction between the two FCER1A encoding gene and environmental exposures including endotoxin, worm infestation and day care centre attendance during early childhood were observed.

CONCLUSION

Common variants in FCER1A strongly influence basal IgE production independently from environmental stimuli. These effects can be observed already in cord blood pointing to altered gene expression in foetus.

Health‐Related Quality of Life in Children and Adolescents with Asthma: Results from the ESTAR Study

Our aim was to assess the psychosocial well-being of asthmatic children and adolescents, the influencing factors, and to determine the effect of inpatient rehabilitation on their quality of life; 226 asthmatic children and adolescents participated in the inpatient rehabilitation (IG). The comparison group (CG) included 92 asthmatic children and adolescents receiving standard medical treatments. Patients were aged between 8 and 16 years and were predominantly male. The health-related quality of life was measured with the German version of the "Paediatric Asthma Quality of Life Questionnaire." Interviews were carried out for IG 2 weeks before the commencement of their inpatient stay and 1 year after their stay ended. The same time schedule was carried out for CG. All patients reported a mild to moderate impairment of their quality of life. Girls described a slightly lower quality of life than boys. With increasing asthma severity, quality of life decreased. Inpatients described a lower quality of life than CG at enrollment. Inpatient rehabilitation resulted in a greater improvement of quality of life over time for IG than for CG. Gender and severity status had no effect on this time course. The only modestly affected quality of life may reflect the good adaptation to the disease and medical treatment. Children and adolescents in the IG recorded improvements in their quality of life. Differences in quality of life based on gender and disease severity were not shown to influence the improvements. In summary, inpatient rehabilitation results in an improvement of health-related quality of life. Further research concerning the psychosocial situation of children and adolescents in this setting is needed.

Safety and tolerability of seasonal ultra-rush, high-dose sublingual-swallow immunotherapy in allergic rhinitis to grass and tree pollens: an observational study in 193 children and adolescents

OBJECTIVE

We conducted a large observational study in 193 children and adolescents with allergic rhinitis due to grass or tree pollens to evaluate the safety and tolerability of an ultrarush high-dose sublingual immunotherapy (SLIT) regimen reaching a maintenance dose of 300 index of reactivity within 90 minutes.

METHODS

Children and adolescents aged 5 to 17 years with at least a 1-year medical history of allergic rhinitis with or without mild to moderate asthma due to tree pollens (birch, alder, hazel) or grass pollens (cocksfoot, meadow grass, rye grass, sweet vernal grass, timothy) were recruited. Standardized grass and tree pollen allergen extracts were used for ultrarush titration and subsequent coseasonal maintenance.

RESULTS

During ultrarush titration, 60 patients (31%) reported 117 predominantly mild and local adverse events, which resolved within 150 minutes. During the maintenance phase, 562 adverse events were reported; the most frequent local events were oral pruritus, burning sensation, lip or tongue swelling, and gastrointestinal symptoms, and the most frequent systemic events were rhinoconjunctivitis and asthma. There was 1 clinically significant asthma event in an 11-year old boy with known asthma in whom SLIT was resumed after an interval of 4 days.

CONCLUSION

Ultrarush titration was safe and well tolerated. Pediatric patients with asthma should be carefully monitored and adequately trained to use their rescue medications.

Early allergic sensitizations and their relevance to atopic diseases in children aged 6 years: results of the GINI study

BACKGROUND

Only a few studies have analyzed the value of early sensitization in predicting the development of atopic disease. The relevance of low immunoglobulin (Ig) E antibody levels in this respect also remains unclear.

OBJECTIVE

To investigate the relevance of sensitization in 12-month-old children in the development of atopic disease by the age of 6 years.

METHODS

We analyzed data for 1290 children with a positive family history of atopy from the prospective, multicenter German Infant Nutritional Intervention (GINIplus) study and investigated the relationship between the presence of detectable specific IgE antibodies at the age of 12 months and the development of atopic disease by the age of 6 years.

RESULTS

In all, 10.9% of children analyzed developed sensitization. At the age of 6 years, 20.6% of children with early sensitization had eczema compared to 9.4% of those without (odds ratio [OR], 2.31; 95% confidence interval [CI], 1.42-3.74). The corresponding figures were 15.4% vs 7.3% for allergic rhinitis (OR, 2.22; CI, 1.31-3.78) and 10.2% vs 2.6% (OR, 3.93; 95% CI, 1.98-7.76) for asthma. Children with early sensitization to aeroallergens had the greatest risk of subsequent atopic disease. Early sensitization did not increase risk in children without eczema within the first year of life. Very low specific IgE levels (0.18-0.34 kU/L) were not significantly associated with any of the outcomes analyzed.

CONCLUSION

Sensitization to common food allergens and to aeroallergens in particular during the first year of life was found to be a strong predictor for the development of atopic disease by the age of 6 years in children with a positive family history of atopy.

Respiratory health and individual estimated exposure to traffic-related air pollutants in a cohort of young children

OBJECTIVES

To estimate long-term exposure to traffic-related air pollutants on an individual basis and to assess adverse health effects using a combination of air pollution measurement data, data from geographical information systems (GIS) and questionnaire data.

METHODS

40 measurement sites in the city of Munich, Germany were selected at which to collect particulate matter with a 50% cut-off aerodynamic diameter of 2.5 microm (PM2.5) and to measure PM2.5 absorbance and nitrogen dioxide (NO2). A pool of GIS variables (information about street length, household and population density and land use) was collected for the Munich metropolitan area and was used in multiple linear regression models to predict traffic-related air pollutants. These models were also applied to the birth addresses of two birth cohorts (German Infant Nutritional Intervention Study (GINI) and Influence of Life-style factors on the development of the Immune System and Allergies in East and West Germany (LISA)) in the Munich metropolitan area. Associations between air pollution concentrations at birth address and 1-year and 2-year incidences of respiratory symptoms were analysed.

RESULTS

The following means for the estimated exposures to PM2.5, PM2.5 absorbance and NO2 were obtained: 12.8 microg/m3, 1.7x10(-5) m(-1) and 35.3 mug/m3, respectively. Adjusted odds ratios (ORs) for wheezing, cough without infection, dry cough at night, bronchial asthma, bronchitis and respiratory infections indicated positive associations with traffic-related air pollutants. After controlling for individual confounders, significant associations were found between the pollutant PM2.5 and sneezing, runny/stuffed nose during the first year of life (OR 1.16, 95% confidence interval 1.01 to 1.34) Similar effects were observed for the second year of life. These findings are similar to those from our previous analysis that were restricted to a subcohort in Munich city. The extended study also showed significant effects for sneezing, running/stuffed nose. Additionally, significant associations were found between NO2 and dry cough at night (or bronchitis) during the first year of life. The variable "living close to major roads" (<50 m), which was not analysed for the previous inner city cohort with birth addresses in the city of Munich, turned out to increase the risk of wheezing and asthmatic/spastic/obstructive bronchitis.

CONCLUSIONS

Effects on asthma and hay fever are subject to confirmation at older ages, when these outcomes can be more validly assessed.

Regulation of ghrelin is related to estimated insulin sensitivity in obese children

OBJECTIVE

To investigate whether ghrelin concentrations and their changes during weight loss in obese children are associated with parameters of glucose and insulin metabolism.

DESIGN

Total plasma ghrelin, insulin and glucose were measured during oral glucose tolerance testing before and after diet-induced weight loss over 6 weeks.

SETTING

In-patient rehabilitation program in a pediatric hospital.

PARTICIPANTS

Twenty-three obese children (age 10-16 years) and 11 normal weight controls (age 10-15 years).

OUTCOME MEASURES

Changes in ghrelin concentrations during weight loss and correlation analysis of changes in ghrelin and changes in parameters of glucose and insulin metabolism. After data collection, subgroup analysis of obese patients with high, medium and low estimated insulin sensitivity whole-body insulin sensitivity index (WBISI) was performed.

RESULTS

Weight loss increased the area under the curve (AUC) of ghrelin by 26% (P<0.001). The increase in ghrelin AUC correlated significantly with improved estimated insulin sensitivity (WBISI) (r=0.69, P<0.001). The independent predicting effect of WBISI was confirmed in multivariate analysis. In children with low WBISI, ghrelin reached the level of control values after weight loss. In children with high WBISI, ghrelin increased markedly above control levels.

CONCLUSIONS

Changes in ghrelin are independently associated with changes in glucose and insulin metabolism. The increase in plasma ghrelin above control levels was limited to obese children with high WBISI.

A prospective, randomized, double-blind, placebo-controlled multi-centre study on the efficacy and safety of sublingual immunotherapy (SLIT) in children with seasonal allergic rhinoconjunctivitis to grass pollen

BACKGROUND

Especially in childhood, sublingual immunotherapy (SLIT) could offer advantages over subcutaneous therapy. However, limited data on its efficacy is available.

METHODS

In four German centres 97 children (age 3-14 years) with allergic rhinoconjunctivitis to grass pollen were enrolled in a prospective, double-blind trial comparing SLIT (Pangramin SLIT; ALK-SCHERAX, 0.5 microg major allergens, three times per week, 32 months) with placebo. Primary endpoint was a multiple symptom-medication score for changes in seasonal diary entries between the first and third year of the study (SLIT n=39; placebo n=38).

RESULTS

The multiple symptom-medication score was significantly reduced by SLIT to 77.3% of the placebo group (P=0.0498). The subsequent analysis of the single endpoints did not reveal significant differences for symptom scores in favour of SLIT (85.1% of placebo group; P=0.22). However, the medication score improved significantly (67.1% of placebo group; P=0.0025). Furthermore, secondary endpoints assessing in vivo immune responses did not differ significantly between the groups. However, retrospective analysis showed some inhomogeneity for clinical and in vitro parameters at the beginning of the study. Allergic side effects with possible relation to the study drug were reported in both groups (SLIT 49%, placebo 27%, P=0.026).

CONCLUSION

Our study indicates that SLIT had a positive effect on the reduction of a multiple symptom-medication score, mainly by significantly reducing rescue medication use, but had no significant effect on symptoms alone in children with rhinoconjunctivitis to grass pollen compared with a placebo.

Salmeterol versus sodium cromoglycate for the protection of exercise induced asthma in children--a randomised cross-over study

OBJECTIVE

Physical activity is an important and frequent trigger of airways obstruction in asthmatic children. We aimed to compare the efficacies of 50 microg salmeterol twice daily and 2 mg SCG four times daily with respect to protection from exercise induced bronchoconstriction (EIB).

METHODS

Twenty seven children and adolescents aged 4 to 16 years with mild or moderate exercise induced asthma (FEV1 70% to 90% predicted) were admitted to the study. Exercise challenge was performed on a treadmill using a predefined protocol in order to produce 10 minutes of exercise at near-maximum targets. The trial had a randomised, cross-over design comprising a 3-day run-in period and two 7-day treatment periods, separated by a one-week washout period.

RESULTS

The mean protective efficacy of salmeterol was larger than that of SCG. A difference between treatments of 39.7% (95% CI, - 0,8 to 68.9%) in favour of salmeterol was calculated using a Hodges-Lehmann-estimate. The maximum post-challenge fall in FEV subset 1 was significantly lower (p<0.001) after salmeterol than after SCG (- 5.6 +/- 6.4% vs. -12.1 +/- 9.3%, respectively). In addition, salmeterol improved base-line lung function to a greater degree than SCG. FEV1 increased by 0.4 l/sec after salmeterol, whereas no improvement was observed after SCG.

CONCLUSIONS

A one-week treatment with salmeterol 50 microg b.i.d in asthmatic children and adolescents provided better protection against EIB and improved baseline lung function as compared to SCG four times daily.

[Long-term effect of indoor rehabilitation on children and young people with moderate and severe asthma]

In a multi-centre trial the effect of indoor rehabilitation in case of bronchial asthma in childhood and adolescence was evaluated on a prospective basis in comparison to an ambulant group of patients. 195 children and adolescents aged between 8 and 16 suffering from bronchial asthma (grading of severity 3 and 4) were included in the trial. The rehabilitation group (RG) included 149 patients, whereas the out-patient reference group consisted of 46 patients. At the beginning of the trial (in the rehabilitation group about 14 days before rehabilitation started) and 12 months afterwards, the pulmonary function (FEV 1, peak flow and MEF50), asthma-related school day off, participation in school sport, asthma management and quality of life were recorded. 12 months after the indoor rehabilitation, the rehabilitation group had significantly better MEF50-values (P = 0.007) than the ambulant group. The rehabilitation group also had significantly better values (P < 0.01) with regard to the asthma management. Already at the beginning of the study both groups indicated a satisfactory participation in school sport with 3.5 hours a week which could not be increased further. The baseline values for asthma-related school day off and quality of life of the rehabilitation group were worse than those of the ambulant group. 12 months after rehabilitation, however, the values were significantly better (P < 0.01) compared to baseline and almost similar to the levels of the ambulant group. Significantly improvements with regard to MEF50, asthma management, school day off and quality of life could thus be achieved by indoor rehabilitation.

Traffic-related air pollution and respiratory health during the first 2 yrs of life

As part of an international collaborative study on the impact of Traffic-Related Air Pollution on Childhood Asthma (TRAPCA), the health effects associated with long-term exposure to particles with a 50% cut-off aerodynamic diameter of 2.5 microm (PM2.5), PM2.5 absorbance, and nitrogen dioxide (NO2) were analysed. The German part of the TRAPCA study used data from subpopulations of two ongoing birth cohort studies (German Infant Nutrition Intervention Programme (GINI) and Influences of Lifestyle Related Factors on the Human Immune System and Development of Allergies in Children (LISA)) based in the city of Munich. Geographic information systems (GIS)-based exposure modelling was used to estimate traffic-related air pollutants at the birth addresses of 1,756 infants. Logistic regression was used to analyse possible health effects and potential confounding factors were adjusted for. The ranges in estimated exposures to PM2.5, PM2.5 absorbance, and NO2 were 11.9-21.9 microg m(-3), 1.38-4.39 x 10(-5) m(-1), and 19.5-66.9 microg x m3, respectively. Significant associations between these pollutants and cough without infection (odds ratio (OR) (95% confidence interval (CI)): 1.34 (1.11-1.61), 1.32 (1.10-1.59), and 1.40 (1.12-1.75), respectively) and dry cough at night (OR (95% CI): 1.31 (1.07-1.60), 1.27 (1.04-1.55), and 1.36 (1.07-1.74), respectively) in the first year of life were found. In the second year of life, these effects were attenuated. There was some indication of an association between traffic-related air pollution and symptoms of cough. Due to the very young age of the infants, it was too early to draw definitive conclusions from this for the development of asthma.

Maternal compliance with nutritional recommendations in an allergy preventive programme

AIMS

To assess maternal compliance with nutritional recommendations in an allergy preventive programme, and identify factors influencing compliance behaviour.

METHODS

Randomised double-blind intervention study on the effect of infant formulas with reduced allergenicity in healthy, term newborns at risk of atopy. Maternal compliance with dietary recommendations concerning milk and solid food feeding was categorised.

RESULTS

A total of 2252 newborns were randomised to one of four study formulas. The drop out rate during the first year of life was 13.5% (n = 304). The rates of high, medium, and low compliance to milk feeding during weeks 1-16 were 83.4%, 4.0%, and 7.5%; the corresponding rates to solid food feeding during weeks 1-24 were 60.0%, 12.1%, and 22.9%. In 5.1% of subjects no nutritional information was available. Low compliance was more frequent among non-German parents, parents with a low level of education, young mothers, smoking mothers, and those who weaned their infant before the age of 2 months.

CONCLUSIONS

Evaluation of allergy preventive programmes should take into account non-compliance for assessing the preventive effectiveness on study outcome.

Familial dysautonomia: a diagnostic dilemma. chronic lung disease with signs of an autoimmune disease

We present an 11-year-old girl with sensory and autonomic neurological dysfunction, and respiratory insufficiency caused by recurrent aspiration. The diagnosis of familial dysautonomia (FD) was confirmed by a missing axonal flare to histamine, miosis in response to conjunctival methacholine and homozygous polymorphic linked markers DS58(18) and DS159(7) on chromosome 9. Ashkenazi Jewish descent could not be ascertained by history. A variety of positive tests for autoantibodies were initially interpreted as evidence for systemic lupus erythematosus vs. overlap syndrome with pulmonary, cerebral, skin, and ocular involvement. The diagnosis of FD was delayed because of the rarity of this disorder in Germany (second case reported). We discuss possible explanations for the misleading immunological findings, including interference by antibodies binding to milk proteins used as blocking reagents in enzyme-linked immunoassays and circulating immune-complexes due to chronic aspiration pneumonitis.

Efficacy and safety of intranasally applied dimetindene maleate solution. Multicenter study in children under 14 years suffering from seasonal allergic rhinitis

The aim of this study was to investigate the efficacy and tolerability of intranasally applied dimetindene (CAS 3614-69-5) 0.1% spray in children suffering from seasonal allergic rhinitis. A total of 100 children under 14 years with acute seasonal allergic rhinitis participated in this randomised, single-blind, reference-controlled, multi-center, parallel group study with two treatment groups. The study took place between 2nd April and 16th September 1996 during the pollen season. Patients were examined at enrollment (day 1), day 8 and day 15. Patients kept diary throughout the 2-week treatment phase. Patients were randomised to receive either dimetindene 0.1% (Fenistil Nasal Spray) or a levocabastine (CAS 79516-68-0) 0.05% solution as reference medication. Both medications were supplied in similar outer packages. A single-blind approach was chosen, because the reference medication levocabastine requires two spray puffs per nostril as a single dose, whereas for dimetindene maleate solution a single spray puff per nostril is sufficient. Dimetindene 0.1% was applied with 1 spray puff (= 0.14 mg dimetindene) in each nostril and levocabastine with 2 spray puff (= 0.10 mg levocabastine) in each nostril every day in the morning before leaving the house and in the evening before going to bed. Additional administration of the spray was allowed up to 4 times a day if needed. Efficacy was assessed as change in severity of characteristic symptoms associated with pollen rhinitis: nasal rhinorrhea, nasal itching, nasal sneezing and nasal congestion. In addition, changes in ocular symptoms, lacrimation, ocular itching and red eyes, global physician's assessment of efficacy at the end of treatment were assessed. The primary criterion change of total nasal symptom severity score between day 1 and day 3 resulted in a statistically equivalent and therapeutically relevant symptom reduction for the two treatments. All secondary criteria showed a similar reduction in symptoms, thus underlining the consistency of the findings. Both nasal sprays were well tolerated. It is concluded from these results that dimetindene 0.1% nasal spray solution is a safe and efficient treatment option for children under 14 years suffering from seasonal allergic rhinitis.

Development of seasonal allergic rhinitis during the first 7 years of life

BACKGROUND

Against the background of the controversial discussion about an increase in allergic rhinitis in recent years, intraindividual longitudinal data is lacking for IgE-mediated seasonal allergic rhinitis (SAR). Little is known about the development of SAR in terms of prevalence and incidence rates from birth to school age.

OBJECTIVE

In a prospective birth cohort, we investigated the development of sensitization and symptoms of SAR. SAR should be defined with high specificity, and associated risk factors should be determined.

METHODS

Annual longitudinal data about seasonal allergic symptoms and sensitization was available for 587 children from birth to their seventh birthday. The definition of SAR was based on a combination of exposure-related symptoms and sensitization.

RESULTS

Up to 7 years of age, SAR developed in 15% of the children. Incidence and prevalence of symptoms and sensitization were low during early childhood (<2%) and increased steadily with age. Children in which SAR had already developed in the second year all were born in spring or early summer, resulting in at least two seasons of pollen exposure before manifestation of SAR. Risk factors assessed by multiple logistic regression analysis were male sex (odds ratio [OR] = 2.4), atopic mothers (OR = 2.6) and fathers (OR = 3.6) having allergic rhinitis themselves, first-born child (OR = 2.0), early sensitization to food (OR = 3.3), and atopic dermatitis (OR = 2.5), whereas early wheezing was not associated with SAR.

CONCLUSION

The development of SAR is characterized by a marked increase in prevalence and incidence after the second year of life. Our longitudinal data further indicate that in combination with the risk of allergic predisposition, at least 2 seasons of pollen allergen exposure are needed before allergic rhinitis becomes clinically manifest.

Exposure to environmental tobacco smoke during the first five years of life-results of a prospective birth cohort study

Objective: To exanine links between environmental tobacco smoke (ETS)-exposure and urnary cotinine excretion during the first five years of life.

Design: Prospective birth cohiort study

Patients: 307 children from the Genran Multicenter Atopy Study (MAS-90)

Measurements and results: ETS-exposure was investigated by questionnaires about the parental smoking habits at home and by analysis of urinary cotinine exacetion by the children at 1 year, 4 years and 5 years of age (capillary gas-chromatography).

Results: From age 1 year to age 5 five years, the proportion of children growig up in smoker households remiained nearly constant (42%). However, 17% of the initial smoker households changed to non smoker households and vice versa. Within the smoker housholds the percentage of smoldng mothers increased from 19.9% to 25.7% and the percentage of smoking fathers decreased from 29.7% to 20.7%. 77% of the mothers and 60% of the fathers smoldng in the households when the child was 1 year old smoked continuously until children were 5 years old. The daily number of cigarettes smoked in the smoker households remained nearly constant (mean value: 6 cig/day).

Urnary cotinine excretion of the ETS-exposed children was found to peak at 1 year of age, decreasing significantly to 5 years of age (p = 0.02). From age 1 year to age 5 years there was a significant correlation between the urinary cotinine excretion of the children and the number of daily cigarettes smoked in the households (p < 0.01). At age 1 year, cotinine excretion was further influenced by the season of the year, the size of domestic apartment and the presence of an atopic mother. At age 5 years, cotinine excretion of the children living in smoker households and attending a kindergarten was significantly lower than that of children living in smoker households but not attending a kindergarten (< O.000 1).

Conclusion: Our results show that ETS-exposure passes through a peak during infancy. This suggests, that the reduced association between ETS-exposure and respiratory symptoms in children after age 2 years reported by earlier studies is due to an agedependent reduction of the ETS-exposure.

Atopic dermatitis in early infancy predicts allergic airway disease at 5 years

BACKGROUND

Screening tests for atopy risk in newborns have a low predictive value. If early atopic symptoms and signs could be used as predictors for the next expected atopic disorder then secondary prevention could be employed. The aim of this study was to evaluate the capacity of early atopic dermatitis to predict aeroallergen sensitization and the manifestation of respiratory atopic disorders at 5 years of age.

METHODS

1314 children of a German prospective birth cohort study MAS-90 were followed from birth up to 5 years of age. Atopic dermatitis, asthma and rhinoconjunctivitis were diagnosed from symptoms and signs at physical examinations and by interviews of the parents. Blood was drawn at 1, 2, 3, and 5 years of age. Aeroallergen sensitization was diagnosed by a specific IgE value of at least 0.35 kU/L (CAP class > or = 1) against any of five respiratory allergens (mite, cat, dog, birch, grass).

RESULTS

Atopic dermatitis in the first 3 months was a risk factor for aeroallergen sensitization at 5 years. The risk increased with a positive family history for atopic diseases. Seventy-seven per cent of children with two atopic parents and early atopic dermatitis were sensitized against aeroallergens at 5 years, i.e. could have been predicted in early infancy without any laboratory tests. Although these risk factors were also significantly associated with the manifestation of allergic airway disease, the positive predictive value for this outcome at age 5 years was not yet as high, i.e. 50%.

CONCLUSION

Infants with very early signs of atopic dermatitis and a positive family history are candidates for early intervention measures against respiratory allergies.

Dimethindene maleate in the treatment of pruritus caused by varizella zoster virus infection in children

The efficacy and tolerability of dimethindene maleate (CAS 3614-69-5, DMM, Fenistil) as drops in the treatment of pruritus in children suffering from chicken-pox were investigated in a study with two different doses of dimethindene maleate and placebo. 128 children, 1 to 6 years of age, were included in a double blind, randomized, placebo controlled, multi-center clinical trial. Patients received either a dosage of DMM of 0.1 mg/kg x d, or 0.05 mg/kg x d, or placebo, respectively. All patients received a commercially available astringent lotion for topical treatment of skin lesions. The primary efficacy criterion which was the change in the itching severity score from baseline to the end of the treatment assessed as area under the baseline (AUB) showed for both treatments with DMM a statistically significant superiority versus placebo in reducing the severity of itching. There was no statistically proven difference between the two verum groups.

Predictability of early atopy by cord blood-IgE and parental history

BACKGROUND

Atopic family history and cord blood IgE have been used as predictors of atopic disease in newborns for about 20 years, but at least for cord blood IgE the sensitivity has been shown to be very low. The objective of this paper was to evaluate whether parental history and cord blood-IgE were more accurate predictors for the appropriate atopic phenotypes in the infants rather than for any atopy.

METHODS

A total of 1314 newborn infants was recruited in six German obstetric departments in 1990 and followed-up for 2 years. Four hundred and ninety-nine (38%) were at high risk for atopy with at least two first degree atopic family members and/or elevated cord-blood IgE concentrations.

RESULTS

The cumulative incidence of atopic dermatitis over the first 2 years of life (AD24) amounted to 20.1%, and there was a significant association with AD history of the mother (OR 2.5, 95%CI 1.46-4.26) and of the father (OR 3.53, 95%CI 1.90-6.54). The cumulative incidence of recurrent wheezing in the first 2 years of life (RW24) amounted to 16.1%, and was positively associated with asthma history (OR 2.11, 95%CI 1.33-3.60) and sensitization history (OR 1.64, 95%CI 1.34-2.36) of the mother, but with neither for the father. RW24 was less prevalent in girls than in boys (OR 0.64, 95%CI 0.47-0.89). Thirty-one per cent of infants were sensitized (CAP test value > 0.35 kU/L) against at least one of nine food or inhalative allergens (S24) and this was significantly associated with cord blood-IgE value (OR 2.43, 95%CI 1.69-3.49), and sensitization history of the mother (OR 1.64, 95%CI 1.18-2.41). Using multiple logistic regression analysis, the prediction of AD24 by AD of parents, of RW24 by asthma of parents, and of sensitization by cord blood IgE was of low accuracy.

CONCLUSION

The predictive capacity of parental history and cord blood IgE is not high enough to recommend them as screening instruments for primary prevention. The majority of atopic manifestations and of sensitization occur in infants with no demonstrable risk at birth.

Indoor allergen exposure is a risk factor for sensitization during the first three years of life

BACKGROUND

The purpose of the study was to investigate the influence of environmental allergen exposure on allergic sensitization in infancy and early childhood.

METHODS

A cohort of 1314 newborns was recruited and followed up prospectively at the ages 12, 24, and 36 months. The levels of major mite (Der p 1 and Der f 1) and cat (Fel d 1) allergens were determined from domestic carpet dust samples by sandwich ELISA. Specific serum IgE antibodies to mite and cat allergens were determined by CAP fluoroimmunoassay (Pharmacia). Logistic regression was used to assess the effects of allergen exposure, age, family history, and cord blood IgE simultaneously on the risk of sensitization.

RESULTS

Children, who had been found to be sensitized at least once during the first 3 years of life, were found to be exposed to significantly higher house dust mite (median, 868 ng/gm vs 210 ng/mg; p = 0.001) and cat (median, 150 ng/gm vs 64 ng/gm; p = 0.011) allergen concentrations in domestic carpet dust compared with the group without sensitization. In homes with low (< or = 25th percentile) dust concentrations, the risk of sensitization to mite (1.6%), and cat (2.0%) is low, compared with 6.5% for mite and 6.3% for cat if the domestic exposure is above the 75th percentile. The dose-response relationships between allergen levels and sensitization indicate that the increase in sensitization risk at low allergen levels is more pronounced in cat allergy (p = 0.002) than in mite allergy (p = 0.026). In the group with a positive family history, lower mite and cat allergen concentrations are needed to achieve specific sensitization compared with the group with a negative family history.

CONCLUSION

Our data indicate that avoidance measures in the domestic environment aimed at the primary prevention of allergen-driven sensitization should be introduced at the earliest possible stage, if possible during infancy.

Sensitization to hen's egg at the age of twelve months is predictive for allergic sensitization to common indoor and outdoor allergens at the age of three years

BACKGROUND

Specific predictors for atopic sensitization in early infancy are prerequisites for preventive intervention studies.

OBJECTIVE

To identify predictors of allergic sensitization to common aeroallergens in infancy, 1314 children in five German cities were followed up from birth (1990) to the age of 3 years.

METHODS

Blood samples were taken from cord blood and at follow-up visits at the ages of 1, 2, and 3 years. Total serum IgE and specific IgE antibodies to common food and inhalant allergens were determined.

RESULTS

Among our study population, risk factors for sensitization to indoor and/or outdoor allergens at the age of 3 years were a positive family history, the presence of hen's egg-specific IgE antibodies (> or = 0.35 kU/L), and increased log- [total IgE] levels at the age of 12 months. Elevated cord blood IgE was not associated with sensitization to inhalant allergens at the age of 3 years. Egg-specific IgE greater than 2 kU/L in combination with a positive family history of atopy was a highly specific (specificity, 99%) and predictive (positive predictive value, 78%) marker for sensitization to inhalant allergens at 3 years of age.

CONCLUSIONS

Hen's egg-specific IgE at the age of 12 months is a valuable marker for subsequent allergic sensitization to allergens that cause asthma, allergic rhinitis, and atopic dermatitis.

The natural course of sensitisation and atopic disease in infancy and childhood

A number of epidemiological studies indicate that the prevalance of allergic airway diseases has been increasing over recent decades, especially in western industrialised countries, for reasons which are not yet completely understood (1, 2, 3). Changes in life style or an increase in indoor allergen exposure due to higher indoor temperature and humidity have been suggested as potential determinants, although evidence for both hypotheses is indirect (4). During the last years we have been following a birth cohort born in 1990 in order to understand the influence of the major genetic and environmental determinants, which are modulating the development of allergic sensitisation and the incidence of atopic symptoms. Sensitisation to indoor allergens has been demonstrated to be one of the major risk factors for the development of asthma in childhood (5, 6, 7, 8). Several cross-sectional studies in older children indicate that specific sensitisation to house dust mites is related to dust mite allergen concentrations in mattress dust (9, 10). Exposure threshold levels for several indoor allergens have been proposed, but individuals vary widely in their susceptibility to levels of exposure, and no absolute value has been identified which could generally ensure minimum risk.

Determinants of cord-blood IgE concentrations in 6401 German neonates

For screening atopy risk in 6401 (84%) of all infants born during the year 1990 in six obstetric departments of five German cities, cord-blood IgE values were determined with CAP-RAST-FEIA. After cases with elevated IgA values had been excluded, 25% of the values were above the detection limit of 0.35 kU/l, and 8.5% were above 0.9 kU/l. Boys had significantly higher values than girls (P < 0.001). The distribution of values was significantly different for different nationalities of mothers (P < 0.001). The percentage of elevated values (> 0.9 kU/l) increased significantly with the number of close family members with atopic history (P < 0.001). Regarding the atopic history of the father, siblings, and mother separately, only the mother's history had a significant association with the cord-blood IgE class (P < 0.001). The IgE values of 81 twin pairs correlated significantly with a coefficient of r = 0.4909 (P < 0.001). The smoking history of the parents during pregnancy showed an association with cord-blood IgE values (P < 0.02). No significant association could be shown between cord-blood IgE distribution and other variables, i.e., gestational age, birth size, birth modus, Apgar score, cord-blood pH value, neonatal problems, parity, age of the mother, medication during pregnancy, educational level of mother or father, time of year, or obstetric department. It is hypothesized that, in addition to some postpartum contamination or placental transfer of maternal IgE, cord-blood IgE values are also determined by the fetal immunologic reaction to intrauterine exposure to allergens and trigger factors, and by genetic influences.

[Criteria for determining the degree of handicap in bronchial asthma in childhood]

Patients history, clinical findings, pulmonary function and necessary therapy are combined for a diagram, which should easily allow to grade childhood asthma for general practitioners, pediatricians and consultants of the health insurance. The grading system is based on the cited literature, dealing in part with the matter, and on the international consensus report on asthma.

Atopic family history. Validation of instruments in a multicenter cohort study

In order to identify newborns at risk for atopic diseases, we developed a family questionnaire and selected specific answers which were suitable to identify atopic family members. The validity of the questionnaire was evaluated by the Phadiatop test results of 793 mothers and 353 fathers. As both screening instruments do not measure the same, the Phadiatop test identifies sensitization to inhalant allergens and the history reflects the clinical manifestation of atopic disease, the agreement between sensitization and manifestation is incomplete. Sensitivity and specificity of the questionnaire screening conditions to reproduce the Phadiotop test result was 64% and 84% for mothers, and 58% and 88% for fathers, respectively. The relative risk for lifetime prevalence of atopic manifestations in Phadiatop positive over negative mothers was calculated to be 3.88 (95% confidence interval = 3.12 to 4.81), and for Phadiatop positive over negative fathers to amount 4.84 (95% confidence interval 3.25 to 7.23). A few relevant answers of 20 were identified by logistic regression analysis to predict the Phadiatop test result nearly, as well as the total questionnaire.

Cord blood T-cell determination: a further useful parameter for atopy screening of the newborn?

In a prospective study, the total CB IgE and T-cell subpopulations in cord blood of 200 newborn children were determined by means of monoclonal antibodies (CD3, CD4, and CD8). There is no correlation between raised cord blood IgE and reduced T-cell ratio in the cord blood or with a positive family history. In a follow-up study carried out at the age of 12 to 14 months, 21% of atopic children had a positive family history and, simultaneously, a reduced total cord blood T-cell rate (CD3). Only 3% of nonatopic children had a positive family history and a reduced cord blood CD3 ratio. Statistically speaking, this distinction is significant (p less than 0.01).

[Development of atopic disease in early childhood--predisposing factors]

In this study, we attempted to find factors which predispose infants to atopy. 200 unselected newborns were followed up to 3 years of age. Children with elevated cordblood IgE or positive family history developed atopic disease significantly more frequent (p less than 0.05, p less than 0.01). Parental smoking or formula feeding alone did not influence the frequency of subsequent atopic disorders. However, in combination with reduced cordblood CD8-cells atopy was observed significantly more often (p less than 0.05, p less than 0.025). Similar results were found in children with reduced cordblood CD3-cells, whose parents were smokers (p less than 0.01). These results suggest that factors which alone do not influence atopy can enhance each other to predispose atopic disease in early childhood.

A placebo-controlled blinded comparison of nedocromil sodium and beclomethasone dipropionate in bronchial asthma

Two hundred and two patients aged 12-78 with chiefly moderate to severe asthma took part in a multicenter randomized blinded group comparison of nedocromil sodium (NS) 4 mg four times daily, beclomethasone dipropionate (BD) 0.1 mg four times daily, and placebo. Patients were assessed at the start and end of a two week baseline and after three and six weeks of treatment. Compared with placebo, both NS and BD significantly improved daytime dyspnoea and day and nighttime cough, as assessed by diary card scores. Lung function (FEV1) was significantly improved in the BD group. In the NS group there was also a significant reduction in concomitant use of inhaled beta 2-agonists. Overall opinions of efficacy by clinicians and patients were significantly in favor of both active treatments over placebo. There were no significant differences between the three treatments for peak expiratory flow rates, morning tightness or nighttime dyspnoea. Comparison between the two active treatments showed no significant differences in any of the variables.

[Radiologic findings and differential diagnosis of bronchial asthma in childhood]

In children with asthma, routine chest X-ray typically shows bilaterally increased air volume, low diaphragms, wide diaphragmatic angles, and often a slender cardiac silhouette with a prominent pulmonic arch. Such an X-ray is not diagnostic of asthma itself, however, but rather of its complications: pneumonitis (particularly in toddlers with infectious asthma), atelectasis due to mucus obstruction, and, rarely, extra-alveolar air trapping (pneumomediastinum with or without cutaneous emphysema more often than pneumothorax). The differential diagnosis has to rule out "pseudo asthma" due to cystic fibrosis, alveolitis, achalasia, and foreign body aspiration.

A placebo-controlled, blind comparison of nedocromil sodium and beclomethasone dipropionate in bronchial asthma

A multi-centre, randomized, blind comparative group study was carried out in 202 adult patients, who had suffered from asthma for at least 2 years, to assess the effectiveness and tolerability of maintenance treatment with either 4 mg nedocromil sodium 4-times daily, 0.1 mg beclomethasone dipropionate 4-times daily or 2 puffs of placebo 4-times daily, given by inhalation. Lung function (FEV1 and sRaw) measurements were made at the beginning and end of a 2-week baseline period and then after 3 and 6 weeks of treatment: assessment were also made of asthma severity. Patients recorded daily on diary cards details of morning and evening PEFR, usage of inhaled bronchodilators, severity of dyspnoea, cough and morning tightness. The results showed that, compared with placebo, both nedocromil sodium and beclomethasone dipropionate-treated patients showed an improvement in FEV1 and a reduction in sRaw values: PEFR increased slightly in all three groups. There was an improvement in asthma severity, diminished rate of dyspnoea and cough, and reduced usage of inhaled bronchodilators in patients receiving active treatment but not in those on placebo. Overall assessment of treatment efficacy by both investigators and patients showed that opinions were significantly in favour of active treatment over placebo. Treatment was well tolerated and no serious side-effects were reported. It was concluded that at the dosages used nedocromil sodium was comparable with and equivalent to inhaled beclomethasone dipropionate in nearly all of the parameters assessed, and both drugs were superior to placebo in the maintenance treatment of asthma in adult patients.

[Effect of nedocromil sodium on the hyperreactivity of the bronchial system in young asthmatic patients]

The protective effect of nedocromil sodium on asthmatic children was investigated by exercise provocation test in a placebo-controlled, double-blind, randomized crossover trial. Lung function impairment during exercise was significantly less (p less than 0.05) with nedocromil sodium than with placebo. The maximum impairment of lung function after exercise challenge was significantly less (p less than 0.05) with nedocromil sodium than with placebo. No side-effect were observed.