OBJECTIVES: Butyrate is one of major metabolites of periodontitis-associated bacteria and often detected in periodontal pockets. Butyrate has been considered to affect human gingival fibroblasts (HGFs); however, there was no information on its long-term effect as occurs in periodontitis. Therefore, this study aimed to evaluate the time-dependent effects of butyrate on HGFs. MATERIAL AND METHODS: The effects of butyrate on HGF proliferation, apoptosis, cell morphology, glucose metabolic activity, butyrate metabolic activity, and cell migration ability were evaluated by cell counting, DNA electrophoresis, cell staining, pH-stat system, HPLC, and scratch test, respectively. RESULTS: HGF proliferation was temporarily inhibited by 5-10 mM butyrate (p < 0.05); however, it resumed at 24 h with morphological changes from spindle to slightly widened (p < 0.05). HGFs cultured with 10 mM butyrate for 12-24 h shifted the glucose metabolic pathway from oxidative phosphorylation to glycolysis (p < 0.05), and increased butyrate consumption, which returned to control levels over 24 h. HGF migration ability tended to decrease at 72 h. CONCLUSIONS: HGF cell proliferation and glucose/butyrate metabolism were temporarily inhibited by butyrate and then recovered in a time-dependent manner, accompanied by changes in cell morphology. These time-dependent effects may help to understand the role of butyrate in the pathology of periodontitis.

The use of video laryngoscopy is growing in patients with anatomical factors suggestive of a difficult airway. This case report describes the successful tracheal intubation of a 54-year-old female patient with limited mouth opening scheduled for third molar extraction under general anesthesia. The Airway scope (AWS) along with a gum-elastic bougie was used to secure the airway after failed direct laryngoscopy and video laryngoscopy using the McGrath MAC with an X-blade. The AWS has a J-shaped structure in which the blade approximates the curvature of the pharynx and larynx. This blade shape makes it easy to match the laryngeal axis with the visual field direction, enabling successful tracheal intubation even for patients with limited mouth opening. A major key to successful video laryngoscopy is to select a video laryngoscope based on the anatomical characteristics of patients with a difficult airway.

Metformin is a metabolic disruptor, and its efficacy and effects on metabolic profiles under different oxygen and nutrient conditions remain unclear. Therefore, the present study examined the effects of metformin on cell growth, the metabolic activities and consumption of glucose, glutamine, and pyruvate, and the intracellular ratio of nicotinamide adenine dinucleotide (NAD+) and reduced nicotinamide adenine dinucleotide (NADH) under normoxic (21% O2) and hypoxic (1% O2) conditions. The efficacy of metformin with nutrient removal from culture media was also investigated. The results obtained show that the efficacy of metformin was closely associated with cell types and environmental factors. Acute exposure to metformin had no effect on lactate production from glucose, glutamine, or pyruvate, whereas long-term exposure to metformin increased the consumption of glucose and pyruvate and the production of lactate in the culture media of HeLa and HaCaT cells as well as the metabolic activity of glucose. The NAD+/NADH ratio decreased during growth with metformin regardless of its efficacy. Furthermore, the inhibitory effects of metformin were enhanced in all cell lines following the removal of glucose or pyruvate from culture media. Collectively, the present results reveal that metformin efficacy may be regulated by oxygen conditions and nutrient availability, and indicate the potential of the metabolic switch induced by metformin as combinational therapy.