Objective To study the effect of sevoflurane pretreatment or aftertreatment on intrapulmonary shunt for patients with one lung ventilation(OLV)during thoracic surgical procedures .Methods 80 ASA I or II patients underwent thoracic surgery with OLV were randomly divided into four groups(n= 20 for each):(1)Propofol group(group P);(2)Sevoflurane pretreatment group(group S1);(3)Sevoflurane aftertreatment group(group S2);(3)Sevoflurane whole-treatment group(group S3) .Blood sam-ples were taken from radial artery and right atrial blood before induction of anesthesia(baseline T .0) ,before OLV(sevoflurane pre-treatment 30 min ,T1) ,after OLV 30 ,60 min and before the end of OLV(T2-T4)and after the end of OLV(T5)for measurement of blood gases and calculation of Qs/Qt .The indexs of hemodynamics and relative clinical data were recorded .Results Arterial oxy-gen pressure of the four groups for OLV significantly reduced ,when compared with double lung ventilation(P<0 .05) ,but there was no significant difference among the four groups(P>0 .05) .Intrapulmonary shunt of the four groups for OLV significantly in-creased ,when compared with double lung ventilation(P<0 .05) ,but intrapulmonary shunt of S1 ,S2 and S3 groups significantly de-creased ,when compared with P group ,and there was no significant difference for S1 ,S2 and S3 groups(P> 0 .05) .Conclusion Sevoflurane can decrease intrapulmonary shunt for patients during OLV ,but there is no significant difference for pretreatment or af-tertreatment or whole treatment and do not increase arterial oxygen pressure .

Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizootic outbreak of pig diseases characterized by high fever, reddened skin and high morbidity and mortality. From June 2006 to April 2007, we have investigated some clinical samples in Hubei province by RT-PCR and cloned several major genes, N, GP5 and NSP2 gene, shown in this study. Phylogenetic analysis of these genes revealed that the highly pathogenic PRRSV variant, ZB, was responsible for 2006 emergent outbreak of pig disease in Hubei province similar with those variants isolated from other provinces in China in 2006, and belongs to the NA-type PRRSV. In the PRRSV variants, the N and GP5 shear about 90% identity with prototypic ATCC VR-2332 and some typical NA-type Chinese isolates, except the 2850bp NSP2 gene (only shares 65% identity with ATCC VR-2332). But they all shear more than and 97% identity with other highly pathogenetic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and 2 deletions in the Nsp2 protein when compared with the previous isolates. Most of the variants found in 2006 epizootic outbreak of pig diseases in China were the farthest variants from the typical NA-type PRRSV in phylogenetic distance, and these diversities may be responsible for the differences in the pathogenicity observed between these variants and original Chinese PRRSV strains.