ObjectiveTo investigate relationship between the degree of placenta praevia, vaginal bleeding and clinical outcomes. MethodsRecords of 89 patients with placenta praevia(mild praevia group 43; severe praevia group 46) were reviewed retrospectively, and outcomes were compared. ResultsThe gestational age at the first bleeding and diagnosis was significantly smaller in severe group than that in mild one (P<0.05). The incidence of antepartum haemorrhage, the times of bleeding and the episodes of heavy bleeding in two groups showed no significant differences(P>0.05). The gestational age at diagnosis and delivery and birthweight were significantly smaller in women with antepartum bleeding than in those without( P<0.01 ). The number of deliveries by emergency caesarean section in women with antepartum bleeding was significantly higher than that in those without (P<0.01). ConclusionThe clinical outcomes of placenta praevia are highly variable. There are no obvious clinical features that are typical in predicting the clinical outcomes. The number of bleeding episodes and the degree of praevia are not associated with outcomes, so they can't be the proof to determine the treatment plan ahead of time.

Objective To define dynamic changes of viral loads and antibody responses in ICR mice naturally infected with hepatitis virus in an MHV contaminative facility .Method A total 50 ICR were housed by different “dirty bedding” exposure.Antigen and antibody was detected after 2,4,8,14,21,28,35,42,56 and 84 days.Result Mouse hepatitis virus (MHV) was detected in lung after 2 days, and positive rate is 20% (1/5).MHV was detected in lung, liver, cecal and feces during 4 and 56 days.The positive rate was 0/5 in lung, liver, cecal and feces on 84 days after experiments.Antibody positive rates were 100%during 8 and 84 days.Conclusion Serological method can be used as the main method for the diagnosis of the daily supervision , and antigen detection method can only be applied to early diagnosis .