IGF-1和FGF-2对神经母细胞瘤细胞分化及SOCS表达的影响

目的 研究胰岛素样生长因子-1（IGF-1）与碱性成纤维细胞生长因子（FGF-2）对神经细胞增殖与分化的共同作用，并探讨SOCS基因表达与二者作用的关系。方法 选用人类神经母细胞瘤SK-N-MC细胞系作为神经细胞的体外模型，分别用IGF-1，FGF-2及联合应用IGF-1和FGF-2处理细胞，于处理后24、48和72h分别观察细胞数量、形态学变化；收获培养48h的细胞，提取总RNA，用RT-PCR法检测SOCS1、2、3 mRNA的表达。结果 处理后24h各组细胞数量及形态无明显变化；处理后48、72h IGF-1组细胞数量较对照组增多，形态上无明显变化，SOCS2 mRNA表达显著下调；FGF-2组细胞数量减少，形态呈明显分化，SOCS2 mRNA表达高于对照组：而IGF-1和FGF-2联合组细胞数量、形态及SOCS2 mRNA表达变化与FGF-2组相似，但程度上更加显著。结论 FGF-2可以削减IGF-1所诱导的人类神经母细胞瘤细胞的增殖作用，而SOCS2 mRNA表达上调可能为其作用机制之一。     

Comparison of in vitro proliferative capacity of human periodontal ligament cells in juvenile and aged donors

OBJECTIVE: The aim of this study is to compare the in vitro proliferative capacity of periodontal ligament (PDL) cells from aged and juvenile donors.
MATERIALS AND METHODS: Flow-cytometric analysis of the cell cycle was used to compare the length of each cell cycle, and the ratio of the cells progressing through the cycles between four PDL cells from juvenile donors and four cells from aged donors. Then, replicative capacity of the PDL cells from three juvenile and three aged donors was compared by serial cultureS. Finally, expression of c-fos was compared between cells proliferating and cells which had reached senescent.
RESULTS: Flow-cytometric analysis of the cell cycle had revealed that although there were no differences in the length of each phase of the cell cycle, significant differences were found in the ratio of the cells entering from Gap 1 to DNA synthesis phase of the cell cycle ( P < 0.025).Replicative capacity was much longer in two cells from juvenile donors (about 20 population doublings), while all cells from aged donors showed short dividing abilities (less than eight population doublings), hence entered senescent phases shortly. Additionally, no c-fos was detected in cells which had reached senescence upon stimulation with serum.
CONCLUSIONS: It is generally believed that aged humans have an impaired wound healing ability. We believe that more fibrotic PDL tissues seen in aged humans might be the reason for this, and suggest that this phenomena might be due to the progressive accumulation of senescent cell populations.     

DENTAL CARIES AND PERIODONTAL DISORDERS IN CHRONIC LIVER DISEASE

Bacterial infections are frequent complications in patients with chronic liver disease (CLD). A potential source of infection may be dental foci. This study was carried out to assess the association of CLD with dental caries and periodontal disease. Dental caries and periodontal examinations were performed prospectively in patients with CLD (group A) and controls without any liver disease (group B). Similar examination was also carried out in alcoholics without liver disease (group C) as well as in cases with portal hypertension but no liver disease (group D) i.e. patients with Non Cirrhotic Portal Fibrosis and Extrahepatic portal obstruction. A total of 231 subjects (Group A:83, group B: 75, group C:46 and group D:27) were studied. Group A included 32 cases with chronic hepatitis B&C, 26 with alcoholic cirrhosis, 14 with postnecrotic cirrhosis, and 11 with cryptogenic cirrhosis. Measures of oral hygiene (p < 0.01), dental care (p < 0.001), and periodontal parameters were worse and the number of teeth requiring treatment (p < 0.05) was higher in alcoholics with or without cirrhosis than in healthy subjects and nonalcoholic patients with cirrhosis. Alcoholics had a lower, total number of teeth than patients without alcohol abuse and healthy controls (p < 0.01). The dental caries and periodontal status of patients with nonalcoholic cirrhosis did not differ significantly from group B. The severity and duration of liver disease had no influence on dental caries and periodontal disease. The presence of chronic alcohol abuse rather than cirrhosis or portal hypertension is a major predisposing factor for dental caries and periodontal diseases. In alcoholics, these diseases appear to be caused primarily by bad oral hygiene and poor dental care.KEY WORDS: Alcohol abuse, Chronic liver disease, Dental caries, Periodontal disease