ABSTRACT
BACKGROUND AND OBJECTIVE: Retinoids, including vitamin A and its synthetic analogs, are known to suppress carcinogenesis in various epithelial tissues and also to inhibit the cell growth of head and neck squamous cell carcinomas (HNSCC). However, the exact mechanism of retinoids is not yet known. The aim of this study is to investigate the effect of all-trans-retinoic acid (RA) on the cell cycle in HNSCCs and to see if the inhibition of cell growth by RA is due to the arrest of cell cycle. MATERIALS AND METHODS: For in vitro study, AMC-HN-4 and AMC-HN-6 (HNSCC cell lines) were treated with 1 nM of RA and cultured for 6 days. CellTiter 96(TM) AQ(ueous) Non-Reactive Cell Proliferation Assay kit was used to analyze the inhibition of cell growth. Flow cytometric analysis was performed for cell cycle analysis. For in vivo study, AMC-HN-4 and AMC-HN-6 were injected subcutaneously into athymic nude mice and RA (20 mg/kg) was orally administered once a day for 30 days. Tumor volumes were measured with digimatic caliper and the cell cycle was analyzed using frozen specimens. RESULTS: The growth of AMC-HN-4 and AMC-HN-6 were inhibited by RA in vitro and in vivo. The inhibitory effect of RA was more significant in AMC-HN-4 than in AMC-HN-6. RA had no significant effect on the cell cycle in the medium containing 10% fetal bovine serum (FBS), but there was a mild increase in the G1 phase in the medium containing 0.5% FBS in vitro. In vivo, the increase in G1 phase was observed in both AMC-HN-4 and AMC-HN-6. Also, G1 arrest was more significant in AMC-HN-4 than in AMC-HN-6. CONCLUSION: This study suggests that RA may induce G1 arrest, which might be associated with the inhibition of cell growth in HNSCCs.
Subject(s)
Animals , Mice , Carcinogenesis , Carcinoma, Squamous Cell , Cell Cycle , Cell Proliferation , G1 Phase , Head , Mice, Nude , Neck , Retinoids , Tretinoin , Vitamin AABSTRACT
BACKGROUND: Ventricular assist devices(VADs) are being used for patients in postcvardiotomy cardiogenic shock status bridge to cardiac transplant settings and in post-myocardial infarction cardiogenic shock. The VAD which was developed at the Deparment of medical engineering in Dankook University College of Medicine was a pneumatically driven device and can maintain pulsatile flow. The goal of this study is to develop animal experimental models using the VAD and to clarify the reliability and hemodynamic property adequacy of end organ perfusion durability and severity of thrombotic-hemolytic tendency of the device. MATERIAL AND METHOD: The pneumatic VAD was applied to 8 adult female lambs, We examined some hemodynamic parameters such as arterial blood pressure pulmonary capillary wedge pressure(pcwp) pulmonary artery pressure(PAP) left atrial pressure hour urine output cardiac index VAD flow EKG to determine the reliability of the VAD and hemodynamic compatibility of the experimental animals within 24 hours of experiment. We also observed the end organ perfusion durability of the VAD and thrombotic-hemolytic property of the VAD after 24 hours of VAD insertion. RESULT: We could monitor all hemodynamic parameters including pcwp PAP cardiac index EKG, adn hour urine as true clinical settings. We observed that the reliability of the VAD was excellent and the hemodynamic property of the experimental animal and end organ perfusion were adequate within 24 hours of experiment. In four lambs surviving 24 hours after insertion the reliability of the VAD and end organ perfusion were excellent and no thrombotic-hemolytic tendency was noted. However after 15 days of experiment the diaphragm of the VAD was torn and it was recommende that the durability of the VAD should be extended. CONCLUSION: e conclude that the pneumatic VAD developed at Dankook University Biomedical Engineering has good hemodynamic property and low thromboembolic tendency and presents adequate end organ perfusion but we noted that the durability of the device should be expanded further. It will be possible to do more reliable experiment in the future according to the animal experimental method developed in this study especially with the heart failure models.