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Background: Predictive models have rarely been used in allergy research and practice. However, they might support physicians in advising patients., Objective: The aim of this study was to create predictive models for the incidence and persistence of allergic rhinitis (AR) during adolescence., Methods: A prospective population-based cohort study was conducted starting at age 9 to 11 years. Potential risk factors for atopic diseases obtained at baseline in 2810 subjects were used to create predictive logistic regression models for the incidence and persistence of physician-diagnosed AR with current symptoms at age 15 to 18 years., Results: Positive skin prick test responses to outdoor allergens at baseline were the most important determinant for both the incidence and persistence of AR until follow-up. For the incidence of AR, positive skin prick test responses to indoor allergens, parental history of asthma, female sex, and not having been breast-fed exclusively for 2 or more months were additional statistically significant independent risk factors. Depending on the number of risk factors present, the probability of the incidence of AR increased from 2% (no risk factors present) to 72% (full model; 95% CI, 58% to 85%). The probability of persistence of AR ranged from 33% (no risk factors present) to 83% (full model; 95% CI, 70% to 97%)., Conclusion: The course of AR over puberty can be predicted using risk factors that are easy to determine in childhood. Sensitization to outdoor allergens seems to play a much greater role for disease development than sensitization to indoor allergens. This might help pediatricians in advising patients., (Copyright © 2011 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Chronic obstructive pulmonary disease (COPD) is one of the most important causes of morbidity and mortality in the world. The disease is often aggravated by periods of increased symptoms requiring medical attention. Among the possible triggers for these exacerbations, meteorological factors are under consideration. The objective of this study was to assess the influence of various meteorological factors on the health status of patients with COPD. For this purpose, the daily number of ambulatory care visits due to COPD was analysed in Bavaria, Germany, for the years 2006 and 2007. The meteorological factors were provided by the model at the European Centre for Medium Range Weather Forecast (ECMWF). For the multivariate analysis, a generalised linear model was used. In Bavaria, an increase of 1% of daily consultations (about 103 visits per day) was found to be associated with a change of 0.72 K temperature, 209.55 of log air surface pressure in Pa, and a decrease of 1% of daily consultations with 1,453,763 Ws m(2) of solar radiation. There also seem to be regional differences between north and south Bavaria; for instance, the effect of wind speed and specific humidity with a lag of 1 day were only significant in the north. This study could contribute to a tool for the prevention of exacerbations. It also serves as a model for the further evaluation of the impact of meteorological factors on health, and could easily be applied to other diseases or other regions.

The 2005 National HIV/AIDS and Reproductive Health Survey (NARHS) in Nigeria provides evidence that multiple sexual partnering increases the risk of contracting HIV and other sexually transmitted diseases. Therefore, partner reduction is one of the prevention strategies to accomplish the Millenium Development Goal of halting and reversing the spread of HIV/AIDS. We consider the numbers of girlfriends, casual, and commercial partners of heterosexual men, reported in the NARHS study, as observed indicators of their latent attitude toward multiple partnering. To explore the influence of risk factors on this latent variable, we extend semiparametric methodology for latent variable models with continuous and categorical indicators to include count indicators. This allows us to simultaneously analyze linear and nonlinear effects of covariates, such as sociodemographic factors and knowledge about HIV/AIDS, on attitude toward multiple sexual partnering, which in turn influences the observable count indicators. The results provide insights for policy makers who are aiming to reduce the spread of HIV and AIDS among the Nigerian populace through partner reduction., (© 2010, The International Biometric Society.)

A possible influence of radio frequency electromagnetic field (RF EMF) exposure on health outcomes was investigated in various studies. The main problem of previous studies was exposure assessment. The aim of our study was the investigation of a possible association between RF EMF and chronic well-being in young persons using personal dosimetry. 3022 children and adolescents were randomly selected from the population registries of four Bavarian cities in Germany (participation 52%). Personal interview data on chronic symptoms, socio-demographic characteristics and potential confounders were collected. A 24-h radio frequency exposure profile was generated using a personal dosimeter. Exposure levels over waking hours were expressed as mean percentage of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference level. Half of the children and nearly every adolescent owned a mobile phone which was used only for short durations per day. Measured exposure was far below the current ICNIRP reference levels. The most reported chronic symptom in children and adolescents was fatigue. No statistically significant association between measured exposure and chronic symptoms was observed. Our results do not indicate an association between measured exposure to RF EMF and chronic well-being in children and adolescents. Prospective studies investigating potential long-term effects of RF EMF are necessary to confirm our results., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Background: The increase in numbers of mobile phone users was accompanied by some concern that exposure to radiofrequency electromagnetic fields (RF EMF) might adversely affect acute health especially in children and adolescents. The authors investigated this potential association using personal dosimeters., Methods: A 24-hour exposure profile of 1484 children and 1508 adolescents was generated in a population-based cross-sectional study in Germany between 2006 and 2008 (participation 52%). Personal interview data on socio-demographic characteristics, self-reported exposure and potential confounders were collected. Acute symptoms were assessed twice during the study day using a symptom diary., Results: Only few of the large number of investigated associations were found to be statistically significant. At noon, adolescents with a measured exposure in the highest quartile during morning hours reported a statistically significant higher intensity of headache (Odd Ratio: 1.50; 95% confidence interval: 1.03, 2.19). At bedtime, adolescents with a measured exposure in the highest quartile during afternoon hours reported a statistically significant higher intensity of irritation in the evening (4th quartile 1.79; 1.23, 2.61), while children reported a statistically significant higher intensity of concentration problems (4th quartile 1.55; 1.02, 2.33)., Conclusions: We observed few statistically significant results which are not consistent over the two time points. Furthermore, when the 10% of the participants with the highest exposure are taken into consideration the significant results of the main analysis could not be confirmed. Based on the pattern of these results, we assume that the few observed significant associations are not causal but rather occurred by chance.

A variety of parameters is available to assess the efficacy of oral antiseptics. Most study protocols select the parameters according to the specific study goal or according to preferences of the researchers. Beside general recommendations for home-use studies, no recommendations exist for other study types. Therefore, pre-selected parameters should be compared within several study designs and the most suitable parameters should be recommended for further application. The following parameters were selected before study start: plaque indices (PlI, Silness & Loe 1964, M-QHI, Turesky et al. 1970), plaque area (PlA), bacterial vitality (BV, Netuschil et al. 1989), gingivitis indices (GI, Loe 1967; M-GI, Lobene et al. 1986; BOP, Ainamo & Bay 1975), gingival crevicular fluid, colony forming units, and the discoloration index (DI, Brecx et al. 1993). The parameters were applied in four study designs: eight-hour substantivity studies, four-day plaque re-growth studies, 21-day experimental gingivitis studies, and six-month home-use studies. Pearson correlation coefficients were computed. The highest correlations were found between PlI and M-QHI and between GI and M-GI (p<0.01) in all corresponding studies and treatment groups. Few middle correlations existed between BOP and the other gingival indices. Neither GI nor M-GI correlated with GCF nor did BV with plaque indices. Inconsistent correlations were obtained between PlA and plaque indices and between PlI and GI. It is concluded, that primary parameters for these designs should be one plaque index and/or one gingivitis index to monitor plaque and gingivitis. The other parameters did not yield additional information about the study outcome.

In the literature and in the daily study routine, a wide range of study designs exists to test the efficacy of mouthrinses. Within these various designs, a considerable number of parameters is applied. Due to the different protocols currently used the outcome of these investigations is hardly to compare. Therefore, it was the aim of the present investigation to assess suitable study designs of different durations, to select and compare parameters, and to find suitable study participants in order to finally recommend more standardized protocols for future studies on oral antiseptics. Eight-hour substantivity studies, four-day plaque re-growth studies, 21-day experimental gingivitis studies, and six-month home-use studies were performed either cross-over or parallel. The clinical studies were randomized, controlled, and investigator-blinded. From most often applied clinical and laboratory parameters, two plaque indices, bacterial vitality, three gingivitis indices, gingival crevicular fluid, colony forming units, and the discoloration index were selected to assess plaque inhibition, gingivitis development, tooth staining, and possible bacterial shifts in the oral cavity. Four or five, respectively, treatment groups were formed that rinsed with the following solutions: chlorhexidine digluconate 0.06%, 0.12%, 0.20%, amine fluoride/stannous fluoride, and a negative control. In addition, all study designs were tested on two different study populations. Population alpha consisted of persons who had a gingival index <0.8 while population beta participants presented a mean gingival index of >/=0.8. Pearson correlation coefficients were calculated between parameters and between subsets of teeth and full-mouth recording. T-tests were applied to compare between populations alpha and beta.

The MobilEe-study was the first cross-sectional population-based study to investigate possible health effects of mobile communication networks on children using personal dosimetry. Exposure was assessed every second resulting in 86,400 measurements over 24 h for each participant. Therefore, a functional approach to analyze the exposure data was considered appropriate. The aim was to categorize exposure taking into account the course of the measurements over 24 h. The analyses were based on the 480 maxima of each 3 min time interval. Exposure was classified using a nonparametric functional method. Heterogeneity of a sample of functional data was assessed by comparing the functional mode and mean of the distribution of a functional variable. The partition was built within a descending hierarchical method. The resulting exposure groups were compared with categories derived from a standard method, which used the average exposure over 24 h and set the cut-off at the 90th percentile. The functional classification resulted in a splitting of the exposure data into two groups. Plots of the mean curves showed that the groups could be interpreted as children with "low exposure" (88%) and "higher exposure" (12%). These groups were comparable with categories of the standard method. No association between the categorized exposure and well-being was observed in logistic regression models. The functional classification approach yielded a plausible partition of the exposure data. The comparability with the standard approach might be due to the data structure and should not be generalized to other exposures., (Copyright 2009 Wiley-Liss, Inc.)

This paper discusses marginal regression for repeated ordinal measurements that are isotonic over time. Such data are often observed in longitudinal studies on healing processes in which, due to recovery, the status of patients only improves or remains the same. We show how this prior information can be used to construct appropriate and parsimoniously parametrized marginal models. As a second aspect, we also incorporate nonparametric fitting of covariate effects via a penalized quasi-likelihood or general estimating equation approach. We illustrate our methods by an application to sports-related injuries.

The ability of calcium channel blockers to prevent and/or to reverse the hypoxemia-induced renal dysfunction was studied in anesthetized and mechanically-ventilated rabbits. Renal blood flow (RBF) and glomerular filtration rate (GFR) were determined by para-aminohippuric acid and inulin clearance, respectively. Each animal was considered as its own control. In 9 rabbits (group 1), verapamil infusion, 1 microgram.kg-1.min-1, did not change basal renal hemodynamics. In a second group (n = 9), hypoxemia induced marked significant decreases in GFR, RBF and urine flow rate (-22 +/- 5%, -18 +/- 6% and -34 +/- 7% respectively). The administration of verapamil partially reversed the hypoxemia-induced renal dysfunction. Likewise, hypoxemia did not induce any change in renal function in verapamil pretreated rabbits (n = 8). This study shows that verapamil is able to prevent and to partially reverse the adverse effects of hypoxemia on renal hemodynamics. The intrarenal infusion of manganese chloride, another calcium channel blocker, was also effective in blunting the hypoxemia-induced changes in the left infused kidney, but not in the contralateral kidney. The overall results demonstrate that a significant protection from hypoxemic renal dysfunction can be achieved by inhibitors of calcium ion transport.

Glutathione exerts a pro-oxidative effect by increasing H2O2-formation in the presence of methemoglobin and a radical-generating substance (e.g. DDC). This effect might contribute to the loss of glutathione in cells in which formation of methemoglobin is provoked by radicals.

Rat livers were initially perfused and then stored at various temperatures up to 4 h. The intra- and extrahepatic status of glutathione, the accumulation of hydrogen peroxide in the preservation medium, the action of a OH-scavenger and of a xanthine oxidase-inhibitor were investigated as candidates for the assessment of oxidative alterations due to ischemia. Furthermore respiratory functions of mitochondria were measured. The increased efflux of GSSG from the liver tissue, the increase of the GSSGtot/GSHtot-ratio and the favourable effects of formate as OH-scavenger and of allopurinol as xanthine oxidase-inhibitor confirm the hypothesis about the oxidative damage under conditions of oxygen deficiency. The nucleotide degradation, especially the steps catalyzed by xanthine oxidase and uricase, is the main metabolic pathway for the generation of oxygen radicals under ischemic conditions.