RESUMO
Aim To express and purify rhα-Gal A with a 6 X His tag via using a serum-free expression system in high-density suspension culture of Chinese hamster ovary cells ( CHO-S) , and to verify the scavenging effect of rhα-Gal A on globular trisaccharide ceramide (Gb3 or GL3) . Methods The construction of recombinant protein expression vector, pcDNA4-GLA, was achieved by fusing the human α-galactosidase cDNA, gla, with 6 X His tag and artificial DNA synthesis. The expression plasmid was transfected into the suspended CHO-S to express rhα-Gal A and then purified. Following this procedure, we determined rhα-Gal A's expression, the enzymatic activity, and the glycosylation of the recombinant enzyme. Co-incubation with cultured cells was performed to examine whether rhα-Gal A could be taken up into the cells and effectively remove Gb3 substrates. Results rhα-Gal A was successfully expressed and purified after transiently transfecting pcDNA4-GLA into the suspended CHO-S, and the yield was up to (100 ±20. 6) mg • L
RESUMO
<p><b>OBJECTIVE</b>To investigate the prevalence of rheumatic heart disease (RHD) among schoolchildren in Guangdong Province and Xinjiang Uygur Autonomous Region.</p><p><b>METHODS</b>Using a cluster sampling method, an epidemiological survey of RHD was conducted in 16 682 primary and high school students by auscultation in Guangdong Province and Xinjiang Uygur Autonomous Region from 2005 to 2006. Review of the clinical records, RHD survey in adults, and examination of the positivity rate of group A beta-hemolytic Streptococcus (GAS) by throat swab cultures in the students aged between 9 and 12 years in the sampled schools were also carried out.</p><p><b>RESULTS</b>No RHD patient was found in the sampled population. In Xinjiang, the prevalence of RHD was 12.9/1000 among adults, higher than that (2.2/1000) in Guangdong Province. The GAS-positive rate in the schoolchildren in Xinjiang ranged from 9.8% to 12.6%, higher than that in Guangdong (2.3%-3.9%).</p><p><b>CONCLUSION</b>The GAS-positive rate among children and incidence of RHD in adults are higher in Xinjiang than in Guangdong. The prevalence of RHD among the schoolchildren shows a reduction compared with that in 1994.</p>