Chitosan wound dressing

This invention is directed to advanced hemorrhage control wound dressings, and methods of using and producing same. The subject wound dressing is constructed from a non-mammalian material for control of severe 5 bleeding. The wound dressing for controlling severe bleeding is formed of a biomaterial comprising chitosan, a hydrophilic polymer, a polyacrylic polymer or a combination thereof, The kind of severe, life-threatening bleeding contemplated by this invention is typically of the type not capable of being stanched when a conventional gauze wound dressing is applied with conventional 10 pressure to the subject wound. The wound dressing being capable of substantially stanching the flow of the severe life-threatening bleeding from the wound by adhering to the wound site, to seal the wound, to accelerate blood clot formation at the wound site, to reinforce clot formation at the wound site and prevent bleed out from the wound site, and to substantially prohibit the flow of 15 blood out of the wound site

Genome-Wide Transcriptional and Physiological Responses of Bradyrhizobium japonicum to Paraquat-Mediated Oxidative Stress▿†

The rhizobial bacterium Bradyrhizobium japonicum functions as a nitrogen-fixing symbiont of the soybean plant (Glycine max). Plants are capable of producing an oxidative burst, a rapid proliferation of reactive oxygen species (ROS), as a defense mechanism against pathogenic and symbiotic bacteria. Therefore, B. japonicum must be able to resist such a defense mechanism to initiate nodulation. In this study, paraquat, a known superoxide radical-inducing agent, was used to investigate this response. Genome-wide transcriptional profiles were created for both prolonged exposure (PE) and fulminant shock (FS) conditions. These profiles revealed that 190 and 86 genes were up- and downregulated for the former condition, and that 299 and 105 genes were up- and downregulated for the latter condition, respectively (>2.0-fold; P < 0.05). Many genes within putative operons for F0F1-ATP synthase, chemotaxis, transport, and ribosomal proteins were upregulated during PE. The transcriptional profile for the FS condition strangely resembled that of a bacteroid condition, including the FixK2 transcription factor and most of its response elements. However, genes encoding canonical ROS scavenging enzymes, such as superoxide dismutase and catalase, were not detected, suggesting constitutive expression of those genes by endogenous ROS. Various physiological tests, including exopolysaccharide (EPS), cellular protein, and motility characterization, were performed to corroborate the gene expression data. The results suggest that B. japonicum responds to tolerable oxidative stress during PE through enhanced motility, increased translational activity, and EPS production, in addition to the expression of genes involved in global stress responses, such as chaperones and sigma factors