Nasopharyngeal stenosis (NPS) is an uncommon but potentially life-threatening condition in cats, capable of causing complete upper airway obstruction in severe cases. Carbon dioxide (CO₂) laser staphylectomy provides precise tissue ablation with minimal collateral thermal injury; however, restenosis could occur when used as a sole treatment modality. Balloon dilation can temporarily restore luminal patency, yet recurrence rates remain high when performed alone. This report describes an 8-month-old Korean Shorthair cat with complete nasopharyngeal stenosis that underwent CO₂ laser ablation as an initial intervention, followed by rapid restenosis within three days. A second procedure combining CO₂ laser ablation with endoscopic balloon dilation achieved short-term maintenance of nasopharyngeal patency. These findings suggest that, in cases of complete stenosis with a high risk of recurrence, a multimodal approach may be more effective than single-modality treatment.

During early embryo development, Oct-4 is an important transcription factor for the early differentiation. The present study was first examined methylation status in distal enhancer and promoter region of Oct-4 during mouse pre-implantation embryo development. In oocyte and sperm, high methylation was observed in both distal and proximal of promoter in Oct-4. Following fertilization, relatively high methylation level remained until 8-cell stage embryos, but decreased at the morula and blastocyst stage. Specific gene knock down of Oct-4 by siRNA injection into zygote induced higher methylation rates of both distal and proximal region ofpromoter of Oct-4. These results suggest a functional link between the DNA methylation status of distal and promoter region in the Oct-4 gene and the gene sequence-specific transcriptional silencing by exogenous siRNA injection during mouse pre- implantation embryos.