A human recombinant haemoglobin designed for use as a blood substitute.

The need to develop a blood substitute is now urgent because of the increasing concern over blood-transmitted viral and bacterial pathogens. Cell-free haemoglobin solutions and human haemoglobin synthesized in Escherichia coli and Saccharomyces cerevisiae have been investigated as potential oxygen-carrying substitutes for red blood cells. But these haemoglobins cannot be used as a blood substitute because (1) the oxygen affinity in the absence of 2,3-bisphosphoglycerate is too high to allow unloading of enough oxygen in the tissues, and (2) they dissociate into alpha beta dimers that are cleared rapidly by renal filtration, which can result in long-term kidney damage. We have produced a human haemoglobin using an expression vector containing one gene encoding a mutant beta-globin with decreased oxygen affinity and one duplicated, tandemly fused alpha-globin gene. Fusion of the two alpha-globin subunits increases the half-life of this haemoglobin molecule in vivo by preventing its dissociation into alpha beta dimers and therefore also eliminates renal toxicity.     

青海双峰驼3项血液钾指标的研究

采用火焰光度法对56峰青海双峰驼的血清钾离子浓度、全血钾离子浓度和红细胞钾离子浓度进行了分析和研究。结果表明:①青海双峰驼的血清钾离子浓度为6.1 mmol/L,成年双峰驼和幼年双峰驼之间没有显著差异;②全血钾离子浓度在18.8~31.2 mmol/L之间,而红细胞钾离子浓度在40.1~80.9 mmol/L之间。成年双峰驼的全血钾离子浓度和红细胞钾离子浓度均高于幼年双峰驼,但无显著差异;③青海双峰驼的全血钾离子浓度呈连续的正态分布。