Aim: To prepare the influenza vaccine lyophilized liposomes and to characterize its particle distribution, encapsulation efficiency and immunogenicity. Methods: Flu vaccine liposome based on the method of thin-film evaporation was prepared using phospholipids , cholesterol and the purified influenza virus split vaccine, and was further subjected to frozen-drying. The polymorph was observed by microscope; the particle distribution and the average size were analysed by transmission electron microscope; its encapsulation efficiency was determined by Lowry method and the antibody titers were assessed by hemagglutination-inhibition after pulmonary delivery to mice. Results: The reconstitated influenza vaccine liposome under electronic microscope were round or elliptic particles evenly distributed at a mean size of 2. 14 祄, with the encapsulation efficiency of more than 80%. The antibody titer through pulmonary delivery was higher than that through intraperitoneal injection. Conclusion: The prepared influenza vaccine lyophilized liposomes possess high encapsulation efficiency, better particle distribution and marked immunogenicity through pulmonary delivery to mice. Pulmonary delivery of influenza vaccine liposomes is a potential immunization approach worthy of further exploitation.

Objective To investigate the incidence of live births with Down syndrome(DS) in Sanya city as well as to discuss the related risk factors .Methods The object of investigation was the 25 032 infants who were born in Sanya city ,then the children with clinical suspected of DS were confirmed by peripheral blood chromosome analysis .Meanwhile ,the clinical data of children and their parents were collected ,calculating the incidence of DS in this region and analyzing the related risk factors .Results In this region , the total incidence of DS was 0 .959‰ ,the incidences in the Han nationality and Li nationality were 0 .834‰ ,1 .442‰ respectively . The mean age of DS children′s mother was 29 .8 years old ,and the incidence of DS increased as their mother grew older .Before pregnancy ,DS children′s mother who had an exposure history of toxicant and drugs accounted for 45 .8% .Conclusion The inci‐dence of DS in Sanya is quite high ,so it is extremely essential to strengthen the women′s pregnancy Down syndrome screening and improve the prenatal diagnosis in this region .