Effects of maleimide-polyethylene glycol-modified human hemoglobin (MP4) on tissue necrosis in SKH1-hr hairless mice

<p>Abstract</p> <p>Objective</p> <p>Tissue hypoxia after blood loss, replantation and flap reperfusion remains a challenging task in surgery. Normovolemic hemodilution improves hemorheologic properties without increasing oxygen carrying capacity. Red blood cell transfusion is the current standard of treatment with its attendant risks. The aim of this study was to investigate the potential of the chemically modified hemoglobin, MP4, to reduce skin flap necrosis and its effect on selected blood markers and kidneys.</p> <p>Materials and methods</p> <p>Tissue ischemia was induced in the ear of hairless mice (n = 26). Hemodilution was performed by replacing one third of blood volume with the similar amount of MP4, dextran, or blood. The extent of non-perfused tissue was assessed by intravital fluorescent microscopy.</p> <p>Results</p> <p>Of all groups, MP4 showed the smallest area of no perfusion (in percentage of the ear ± SEM: 16.3% ± 2.4), the control group the largest (22.4% ± 3.5). Leukocytes showed a significant increase in the MP4 and dextran group (from 8.7 to 13.6 respectively 15.4*10⁹/l). On histology no changes of the kidneys could be observed.</p> <p>Conclusion</p> <p>MP4 causes an increase of leukocytes, improves the oxygen supply of the tissue and shows no evidence of renal impairment.</p

Sorption and fractionation of dissolved organic matter and associated phosphorus in agricultural soil

Molibility of dissolved organic matter (DOM) strongly affects the export of nitrogen (N) and phosphorus (P) from oils to surface waters. To study the sorption an mobility of dissolved organic C and P (DOC, DOP) in soil, the pH-dependent sorption of DOM to samples from Ap, EB, and Bt horizons from a Danish agircultural Humic Hapludult was investigated and a kinetic model applicable in field-scale model tested. Sorption experiments of 1 to 72 h duration were conducted at two pH levels (pH 5.0 and 7.0) and six initial DOC concentrtions (0-4.7 mmol L-1). Most sorption/desorption occurred during the first few hours. Dissolved organic carbon and DOP sorption decreased strongly with increased pH and desorption dominated at pH 7, especially for DOC. Due to fractionation during DOM sorption/desorption at DOC concentrations up to 2 mmol L-1, the solution fraction of DOM was enriched in P indicating preferred leaching of DOP. The kinetics of sorption was expressed as a function of how far the solution DOC or DOP concentrations deviate from "equilibrium". The model was able to simulate the kinetics of DOC and DOP sorption/desorption at all concentrations investigated and at both pH levels making it useful for incorporation in field-scale models for quantifying DOC and DOP dynamics