ABSTRACT
Impaction of permanent teeth during the mixed dentition stage is relatively common in clinical practice, but impaction of mandibular first molars is rare. This case report presents an impaction of the mandibular first molar due to a tooth-like hard tissue lesion. An 8-year-old girl was diagnosed with an impacted mandibular first molar. The roots of the impacted molars were almost completely developed. A spherical tooth-like hard tissue with a diameter of approximately 2 mm was observed at the alveolar crest between the impacted mandibular first and second molars. The lesion causing the impaction was excised, and the first molar was fenestrated and allowed to erupt naturally. We showed that even if the tooth root is almost complete, natural eruption can be expected if the lesion is removed and space for eruption is secured.
ABSTRACT
PURPOSE: Methyl-CpG binding protein 2 (MeCP2)-deficient (Mecp2-/y) mice exhibit apneas that resemble respiratory abnormalities observed in Rett syndrome (RTT) patients. The present study aimed to clarify whether Mecp2-/y mice show diurnal variations in apnea as seen in RTT and how the MeCP2 deficiency affects monoaminergic systems that control breathing. METHODS: In 7-week-old Mecp2-/y mice, 24 h variation of apnea and effects of milnacipran, a serotonin/noradrenaline reuptake inhibitor, on the apnea were evaluated. The number of vesicular monoamine transporter 2 (VMAT2)-immunoreactive puncta in the caudal medulla was counted. Further, the effects of valproate (VPA) on the expression of tyrosine hydroxylase (TH) mRNA in the ventrolateral medulla of mice were assessed by RT-qPCR. RESULTS: Apnea occurred more frequently during the light phase under a 12:12 h light/dark environment in Mecp2-/y mice and milnacipran reduced apnea during the light phase but not during the dark phase. The number of VMAT2-immunoreactive puncta was reduced in Mecp2-/y mice. VPA treatment significantly increased TH mRNA expression in Mecp2-/y mice. CONCLUSION: Alteration of monoaminergic systems in the caudal medulla of Mecp2-/y mice is potentially relevant to the light-sensitive diurnal increase of apnea, and an improvement in monoaminergic neurotransmission can ameliorate the diurnal increase of apnea in Mecp2-/y mice.
