灰色数列预测模型在成骨细胞体外培养中的应用

目的：灰色模型是运用一定的数学方法使信息不完全明确的系统经数据处理后能得到较明确结果的一种数学预测模型，体外细胞培养的影响因素较多，属于信息不完全明确的灰色系统，故运用灰色GM（1，1）模型对成骨细胞增殖、分化的变化规律进行预测，验证模型在体外细胞培养中的可应用性。方法：实验于2005—11／2006—03在广东医学院药理教研室完成。①实验过程：应用酶序列消化分离培养法培养新生大鼠颅骨成骨细胞；用MTT法测定体外培养成骨细胞在不含血清培养液A值，以了解成骨细胞的增殖情况；对硝基苯磷酸盐法观察体积分数为0．01的胎牛血清培养液对体外培养成骨细胞分泌碱性磷酸酶活性的影响，代表成骨细胞的分化情况。②灰色GM（1，1）模型建立：运用灰色系统理论，通过SAS8．1软件对体外培养成骨细胞MTT值和碱性磷酸酶OT值进行分析和预测。结果：运用灰色系统理论的后验差检验方法对模型进行检验，MTT这一指标的平均相对误差为4．4％，碱性磷酸酶这一指标的平均相对误差为7．04％，后验差比值为0．048和0．315，综合评定该模型为“好”。结论：灰色GM（1，1）模型对体外培养成骨细胞MTT值和碱性磷酸酶的OT值变化的预测精度高，结果可靠。体外培养成骨细胞MTT值和碱性磷酸酶的OT值的变化可用灰色GM（1，1）模型进行预测。     

No evidence of chikungunya virus and antibodies shortly before the outbreak on Sri Lanka

A massive outbreak of chikungunya disease occurred on Sri Lanka in 2006. Reasons for the explosive nature of the epidemic are being intensively discussed. According to recognised and anecdotal concepts, absence of human population immunity against chikungunya virus (CHIKV) might have supported virus amplification. However, formal proof of concept is lacking. This study determined the prevalence of anti-CHIKV IgG antibodies as well as CHIKV RNA shortly before the outbreak. Two hundred and six human sera were collected from patients with acute febrile illness in 2004/2005. Validated indirect immunofluorescence and real-time RT-PCR assays for dengue as well as CHIKV were employed. Laboratory evidence of dengue virus infection was seen in 67% of patients, indicating virus activity and exposure to Aedes spp. vectors. These vectors are the same as for chikungunya. However, no evidence of acute or previous chikungunya infection could be demonstrated in the same cohort. This study gives formal evidence that the absence of human population immunity correlated with a large chikungunya epidemic. M. Panning and D. Wichmann contributed equally to this work.