RESUMO
The surface lipopolysaccharide of gram-negative bacteria is both a virulence factor and a B cell antigen. Antibodies against O-antigen of lipopolysaccharide may confer protection against infection, and O-antigen conjugates have been designed against multiple pathogens. Here, we describe a simplified methodology for extraction and purification of the O-antigen core portion of Salmonella lipopolysaccharide, suitable for large-scale production. Lipopolysaccharide extraction and delipidation are performed by acetic acid hydrolysis of whole bacterial culture and can take place directly in a bioreactor, without previous isolation and inactivation of bacteria. Further O-antigen core purification consists of rapid filtration and precipitation steps, without using enzymes or hazardous chemicals. The process was successfully applied to various Salmonella enterica serovars (Paratyphi A, Typhimurium, and Enteritidis), obtaining good yields of high-quality material, suitable for conjugate vaccine preparations.
Assuntos
Precipitação Química , Filtração , Antígenos O/isolamento & purificação , Salmonella/metabolismo , Reatores Biológicos , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Hidrólise , Antígenos O/análise , Antígenos O/metabolismoRESUMO
Research in vascular exercise has demonstrated remarkable improvement in symptoms of claudication without more expensive and invasive interventions. During the past 5 years, 86 patients have graduated from The Brown University Supervised Vascular Exercise Program. Patients demonstrate a threefold improvement in maximum walking distance after 12 weeks of training. Information available on 22 patients at 1-year and 2-year follow-ups show walking distance is improved or maintained with continued training. Components of the program are presented in 3 phases. Phase 1 addresses the comprehensive nursing assessment, cardiac screening, and progressive treadmill testing. Phase II includes specific method of exercise prescription and educational needs of peripheral vascular disease patients. Phase III discusses the importance of maintenance and motivating patients to continue.