Snoring, obstructive sleep apnea, and upper respiratory tract infection in elementary school children in Japan.

PURPOSE: Both obstructive sleep apnea (OSA) and the common cold are disorders of the upper respiratory tract, and may be associated. However, studies on the association between OSA and upper respiratory tract infections (URTI) in children are scarce. The aim of this study was to investigate possible associations between snoring, the severity of OSA, and URTI in elementary school children. METHODS: This was a cross-sectional study in a community cohort of elementary school children (first and second graders) in Japan. Information on sleep habits, history of URTI, and OSA risk was obtained from a parental questionnaire. Children underwent overnight tracheal sound recordings from which apnea-hypopnea index was estimated. Multivariable logistic analysis was employed to define the association between snoring, OSA, and URTI ≥ 3 episodes over six months. RESULTS: Of the 922 potential enrollees, 653 children and their parents (71%) agreed to participate in the study. Multivariable-adjusted ORs for URTI were 1.73 (95%CI: 1.16 to 2.59) in children who snored 1 to 4 nights per week and 2.82 (95%CI: 1.26 to 6.28) in snoring ≥ 5 nights per week compared with never snoring (reference). Likewise, subjectively reported louder snoring, as well as objectively defined louder sound levels, were significantly associated with URTI. In addition, OR for URTI in children with an estimated apnea-hypopnea index ≥ 2.0 events/hour was 2.65 (95%CI: 1.32 to 5.31) compared to children with apnea-hypopnea index less than 1.0 events/hour (reference). CONCLUSIONS: Snoring and severity of OSA as measured by nocturnal tracheal sound recordings were associated with increased susceptibility to URTI in elementary school children.

Validity and reliability of the Japanese version of the severity hierarchy score for pediatric obstructive sleep apnea screening.

OBJECTIVE: This study aimed to evaluate the validity and reliability of the Japanese version of the severity hierarchy score (J-SHS) in the screening of pediatric obstructive sleep apnea (OSA) among Japanese community children. METHODS: A total of 922 children from elementary schools in Tokyo were recruited. Their parents completed the J-SHS questionnaire, and the children underwent an overnight Tracheal Sound (TS) recording. The reliability of the J-SHS was assessed by Cronbach's alpha coefficients and Spearman's correlation. Construct validity was determined by factor analysis. The discriminative ability to diagnose OSA was evaluated by constructing ROC curves. RESULTS: Five hundred and seventeen children (51.8% male, mean age 7.1 ± 0.7 years) were included. Cronbach's alpha coefficient was 0.80. Factor analysis resulted in a two-factor structure, with factor loadings all above 0.4. A J-SHS score of >1.88 exhibited a 60% sensitivity, 93% specificity, and an area under the curve (AUC) of 0.78 for detecting an apnea-hypopnea index (AHI) of ≥5/h; a J-SHS score of >2.06 exhibited a 75% sensitivity, 84% specificity and AUC of 0.84 for detecting an AHI of ≥3/h among the children with a snoring frequency above two nights/wk. CONCLUSION: The J-SHS exhibits good performance as a screening tool providing a quick and straightforward approach for identifying Japanese children at risk for OSA.

Complement activation on surfaces carrying amino groups.

The complement system is strongly activated by surfaces carrying nucleophilic groups, such as hydroxyl (OH) groups, and triggered by deposition of complement protein fragment, C3b. Surfaces carrying amino groups, the other representative nucleophilic group, are expected to be potential activators of the complement system through the alternative pathway. Few studies thus far have examined the potential of artificial materials carrying amino groups in activating the complement system. In this study, we employed a self-assembled monolayer (SAM) of 11-amino-1-undecanethiol (NH2-SAM) and a polyethyleneimine (PEI)-coated surface as model surfaces to study interactions between amino groups and serum complement pathway. SAMs of 11-mercaptoundecanol (OH-SAM) and 1-dodecanethiol (CH3-SAM) were used as control surfaces, respectively. Although much protein was adsorbed from serum solutions on the two types of amino surfaces, amounts of C3b deposition were much less than those observed on OH-SAM. Amounts of C3a released on the amino surfaces were same levels as that of CH3-SAM, but significantly smaller than that on OH-SAM. These facts suggest that the nucleophilic amino groups on NH2-SAM and PEI-coated surfaces do not directly activate the alternative pathway, but the protein adsorbed layers formed on amino surfaces activate it, but to an extent much smaller than that on OH-SAM. In addition, we found no deposition of C1q molecules on the amino surfaces, suggesting that these surfaces fail to activate the classical pathway. However, more careful studies are needed to conclude it, because it is known that C1q is only transiently detected at typical classical activation interfaces.

Deposition of complement protein C3b on mixed self-assembled monolayers carrying surface hydroxyl and methyl groups studied by surface plasmon resonance.

Since complement activation is recognized as a common response of the host defense system when an artificial medical device is applied to a patient, great effort has been devoted to studies on the interaction of the complement system with artificial materials. However, some uncertainties remain, partially because of the lack of well characterized surfaces and suitable analytic methods for study of the surface phenomena that occur on artificial materials under physiologic conditions. In this study, we employed self-assembled monolayers (SAMs) and the surface plasmon resonance (SPR) technique to study interactions of the serum complement with well characterized surfaces. Self-assembled monolayers carrying various concentrations of hydroxyl groups were prepared using 11-mercapto-1-undecanol (C11-OH) and one of n-nonanethiol, n-dodecanethiol, and n-hexadecanethiol. The amount of NHS deposition on the SAMs increased with increasing C11-OH content of the SAMs, and the amount of anti-C3b antibody immobilization formed on the NHS deposition layers increased with increasing C11-OH content of the SAMs. These results clearly demonstrate that a large amount of C3b, produced through the activation of the complement system, binds covalently to and is adsorbed by hydroxyl-group-rich surfaces. The combination of SAMs and the SPR technique is suitable for studying the interaction of the complement system with solid surfaces, and the results should give basic information needed for a rational design of biocompatible surfaces on synthetic materials.