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Circadian rhythm is an endogenous daily variation observed in most physiological functions including salivary secretion. Irregular lifestyle causes many diseases such as obesity and sleep disorders. The aim of this study is to examine the effects of the timings of sleep and meal on the prevalence of dental caries. Study was conducted at university hospital in Japan. We asked 230 children (1–16 years old) to record the following life habits for 8 days: waking time, bedtime, mealtimes, snacking frequency, and tooth brushing frequency. We analyzed sleep habits from all data and compared dental caries and life habits using data from subjects with primary (2–7 years old) or permanent (11–16 years old) dentition period. The number of dental caries assessed using the decay or filled teeth (dft) index correlated with bedtime, supper time, regularity of supper time, and snacking frequency in subjects with primary dentition. Multiple regression analysis revealed that bedtime and snacking frequency were mutually independent risk factors for dental caries. No correlations were found between the prevalence of dental caries and other measurement items. The number of caries correlated with the regularity of supper time and age in subjects with permanent dentition. Children with daily life habits associated with eveningness have a higher prevalence of dental caries. [ABSTRACT FROM AUTHOR]

Summary Influenza A virus (IAV) infection is initiated by the attachment of the viral glycoprotein hemagglutinin (HA) to sialic acid on the host cell surface. However, the sialic acid-containing receptor crucial for IAV infection has remained unidentified. Here, we show that HA binds to the voltage-dependent Ca 2+ channel Ca v 1.2 to trigger intracellular Ca 2+ oscillations and subsequent IAV entry and replication. IAV entry was inhibited by Ca 2+ channel blockers (CCBs) or by knockdown of Ca v 1.2. The CCB diltiazem also inhibited virus replication in vivo . Reintroduction of wild-type but not the glycosylation-deficient mutants of Ca v 1.2 restored Ca 2+ oscillations and virus infection in Ca v 1.2-depleted cells, demonstrating the significance of Ca v 1.2 sialylation. Taken together, we identify Ca v 1.2 as a sialylated host cell surface receptor that binds HA and is critical for IAV entry. [ABSTRACT FROM AUTHOR]