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Red blood cells (RBCs) possess intact cyto-architectures while haemoglobin (Hb) is a cell-free, homogeneous solution. Both RBCs and Hb are generalized oxygen carriers. In this paper, kinetic studies on oxygen-releasing of high concentration of Hb and RBCs under various conditions were carried out regarding Hb and RBCs as fluids. Among them, Hb under specific conditions was seen as the simplest Hb-based oxygen carrier (HBOC), Also, factors affecting the oxygen releasing of Hb and RBCs, including osmotic pressure, viscosity and allosteric agent, have been well studied. Analysis of the results from the measurement above showed that kinetics of oxygen releasing of either pure Hb or the simplest HBOCs was obviously different from that of RBCs. The oxygen-releasing time of Hb was shorter and the oxygen-releasing rates of Hb were quicker than those of RBCs under various conditions. Therefore, as fluids, only by changing the milieus it exists in, Hb could not achieve the expected oxygen-releasing effect on the microcirculation so well as RBCs do in the same system, irrespective of the interaction between the fluids and blood vessels. Furthermore, kinetic properties of HBOCs must be considered and matched with those of RBCs in the study of HBOCs.

A rapid and sensitive high-performance liquid chromatography (HPLC) method for vitamin C (Vc) determination was developed in hemoglobin-based oxygen carriers (HBOCs) solution. After polymerized hemoglobin precipitation, Vc could be tested out within 5 min. The standard curve was linear in Vc quantity of 0.00-3.00 μg. Vc recovery was 103.56-108.68%, and relative standard deviation values of the repeatability and precision were below 1.00%. The limits of detection and limits of quantification were 0.002 ppm and 0.01 ppm, respectively. Furthermore, the application of established HPLC methods in methemoglobin reduction by Vc under different pH indicated that higher pH values could accelerate the reduction. This study suggested the potential application of established HPLC method in HBOCs research and development.

The new research tried to improve the distribution of molecular weight of Hb-based oxygen carriers (HBOC), a bottleneck of glutaraldehyde (GDA)-polymerization process. The orthogonal experiments were done on the basis of the early study of human placenta Hemoglobin (Hb)-crosslinked-GDA and three factors were selected including the molar ratio of GDA and Hb, Hb concentration, and the rate of the feeding GDA. The optimal match condition of polymerization process prepared for the purpose of lower mean molecular weight, content of super-weight molecule, and the content of dimer. The results showed that the molar ratio of GDA and Hb was the greatest influencing factor on the molecular weight distribution of polymerized-Hb, followed by the Hb concentration, and the last is the rate of feeding GDA. The optimum matching conditions had reached the objective that the mean molecular weight with 155.54 ± 5.79, the content of dimer with 17.23 ± 3.71, and content of super-weight molecule with 0.17 ± 0.09, and the results can be repeated in the 30 times expansion experiments.

The molybdenum blue method was used to determine the content of reduced vitamin C (Vc) in a solution of polymerized hemoglobin-based oxygen carriers (HBOCs) of the human placenta. The conditions of absorption wavelength, HCl addition, and reaction time, were investigated. The results of validation experiments showed that under the optimized conditions, a standard curve was confirmed with good linearity of 0.9985, for the Vc amount ranging from 0–200 μg. The values for relative standard deviation (RSD) of the precision and repeatability were both below 5%. Vc recovery was in the range of 97–102%. The conclusion could be made that a reduction in Vc content could be tested effectively by the molybdenum blue method.

Oxidative reactions of hemoglobin (Hb) are still a serious problem for Hb-based blood substitute development. Although varieties of antioxidant strategies have been suggested, this in vitro study examined the ability of the ascorbate, N-Acetyl-L-Cysteine (NAC), 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-1-oxygen free radicals (TEMPO) and their reductant system in preventing Hb oxidation. The content of ferric Hb is monitored in the process of vitamin C (Vc), NAC, TEMPO and their reductant system. The results suggest that ascorbate is effective in reducing ferryl Hb, and TEMPO with Vc/NAC could obviously shorten the reaction time, but it does not play the role of Met-Hb reductases. It demonstrates that TEMPO did little to recover Hb under oxidative stress.

This study was to investigate whether glutaraldehyde-polymerized human placenta hemoglobin (PolyPHb) could attenuate ischemia/reperfusion (I/R)-induced liver injury. Isovolemic hemodilution of SD rats was performed by exchanging 15% total blood volume with PolyPHb. I/R was induced by left liver lobes pedicle cross-clamping for 60 min and reperfusion for 2 h. Blood pressure moderately elevated after PolyPHb infusion and returned to basal level within 10 min. The hepatic histopathological damage and the activities of liver injury markers were reduced by PolyPHb. The TUNEL staining and caspase assay indicated hepatic apoptosis was also inhibited. Therefore, our findings suggest PolyPHb can reduce liver I/R injury.

The goal of this study was to investigate whether hemoglobin-based oxygen carrier (HBOC) attenuated ischemia/reperfusion (I/R)-induced kidney injury. Male SD rats were randomly divided into a sham group, I/R group, and HBOC group (injection of 0.1 gHb/kg PolyPHb). The ischemia was induced by bilateral renal pedicle cross-clamping for 45min. Then the clamp was released to allow 24h reperfusion. Without increasing blood pressure, PolyPHb reduced the blood urea nitrogen and creatinine in plasma and attenuated the tumor necrosis factor-α and interleukin-8 in kidney tissue. Therefore, our findings suggest that PolyPHb could reduce kidney injury after I/R injury, and this effect was probably associated with the depressed inflammatory response.

This study was designed to investigate whether polymerized human placenta hemoglobin (PolyPHb) attenuated hemorrhagic shock-induced lung injury. A mean arterial pressure (MAP) of 30mmHg was maintained for 60 min. Then, all the rats were randomly resuscitated with hetastarch, whole blood, or PolyPHb. The result indicated that PolyPHb greatly improved the MAP and pulmonary function, and significantly reduced the release of inflammatory cytokines, histopathological changes, and pulmonary edema. Therefore, our findings suggest that PolyPHb could reduce pulmonary injury after hemorrhagic shock, and this effect was probably associated with the depressed inflammatory response.

To investigate whether polymerized human placenta hemoglobin (PolyPHb) improved hemodynamic parameter recovery and cardiac function after hemorrhagic shock, a mean arterial pressure (MAP) of 30 mmHg was maintained for 60min. Then, all the rats were randomly resuscitated with hetastarch (HES), shed blood (Whole Blood), or PolyPHb (PolyPHb). The MAP was greatly improved by PolyPHb, but it was still lower than that of the Whole Blood group. Meanwhile, the cardiac function and enzyme releases in the PolyPHb group were similar to the HES group. Therefore, our findings suggest that PolyPHb moderately improved hemodynamic recovery and provided little cardioprotective effect in hemorrhagic shock.

This study was to investigate whether polymerized human placenta hemoglobin (PolyPHb) given before ischemia protects in vivo rat heart function against ischemia/reperfusion (I/R) injury. Forty-five male Sprague-Dawley rats were randomly divided (n = 15 per group) into a sham group, control group (pretreatment with Lactated Ringer's solution), or PolyPHb group (pretreatment with 0.1 gHb/kg PolyPHb). Rat hearts were subjected to 30-min ischemia by occlusion of left anterior descending, followed by 2-hr reperfusion. As compared to the control group, PolyPHb preserved cardiac function and reduced cardiac troponin-I release and histopathological changes. Therefore, PolyPHb pretreatment provided a profound cardioprotective effect on the in vivo rat heart.

This study was designed to compare the influence of deoxygenated hemoglobin-based oxygen carrier (HBOC) pretreatment and ischemia preconditioning on cardiac ischemia/reperfusion (I/R) injury. Langendorff-perfused rat hearts were pretreated with 0.1 gHb/dL deoxygenated HBOC or ischemia, then subjected to 50-min warm ischemia and 2-hr reperfusion. The results indicated that deoxygenated HBOC pretreatment and ischemia preconditioning both equally improved the recovery of cardiac function, and reduced the cardiac enzyme release and myocardial histopathological changes as compared to the control group. Therefore our study demonstrated that deoxygenated HBOC pretreatment and ischemia precondition provided equivalent protection to the isolated heart against I/R injury.

This study was designed to investigate the influence of polymerized human placenta hemoglobin (PolyPHb) pretreatment on ischemia/reperfusion (I/R) injury-induced myocardial apoptosis. Isolated Sprague-Dawley rat hearts were perfused by Langendorff model. After basal perfusion, hearts were arrested by St.Thomas’ solution (STS) with (Pre-HBOC group) or without PolyPHb (STS group), then subjected to I/R injury. Our results showed that PolyPHb pretreatment greatly reduced the TUNEL-positive myocardial cells and decreased the caspase-3 activity and cleavage, which was further confirmed by the linear regression analysis. Therefore, PolyPHb pretreatment was beneficial to attenuation of myocardial apoptosis and provided protection to the heart against I/R injury.

Hemoglobin-based blood substitute is widely studied. As the starting materials, hemoglobin (Hb) is mainly supplied from outdated human blood and animal sources. But there are many disadvantages. As the alternative source, human placenta hemoglobin (PHb) has its own advantages. We take the lead in being occupied in the research of blood substitutes based on the placenta blood. Purified PHb readily undergoes dissociation to form two dimers that are easily filtered by the kidneys and have high 02 affinity (low P50), failing to transport 02 to tissues. As a first step, to enhance PHb stability and P50, we first adopted DBBF to modify deoxyPHb leading to DBBF-alpha PHb. According to detection, we knew that the PHb stability was improved, 02 affinity of the PHb solution was reduced, DBBF-alpha PHb had the appropriate capacity of oxygen-carrying and oxygen-unloading, and DBBF-alpha PHb kept the biological activity well. On the whole DBBF-alpha PHb could be considered as a first step toward the synthesis of a potential blood substitute.

Let K be a compact subset of R, μ be a σ-finite positive measure, and f be an integrable function on K. One-sided L 1 norm is introduced, and it is defined as A best approximation of f from a subspace U in this norm and the uniqueness of the best approximation in this norm are discussed.

For pilot-scale manufacturing of hemoglobin-based oxygen carrying drugs, we should get highly pure and viral inactivated hemoglobin (Hb) at high recovery. In our method, placenta hemoglobin (PHb) solutions were purified by heating in the presence of reducing agent and deoxygenating conditions so that heat-sensitive proteins were selectively precipitated and virus was inactivated. The optimum preparative condition resulted in highly purified PHb solution (>99% pure) with approximate 90% recovery and less than 2% of MetHb content, maintained oxygen carrying capacity, residual phospholipids less than 1 ppm, free of endotoxin, bacteria, type A&B antigens and virus. Finally, we compared the efficacy of blood exchange on rat with poly-PHb and poly-Hb from adult blood. The results showed no significant difference between two products. Therefore, the placenta Hb obtained from this method could be supplied as materials for oxygen carrying drugs.

Let P be a bounded linear projection from C[a,b] to a subspace V = span{v 1…m}. In this paper we study those projections P with Pf interpolating f at n or more distinct points for all f ∈C[a,6]. The same problem for best approximations is also studied.

Let 0