Kinetics of volume expansion during infusion of Ringer’s solution based on two volume model

In this work mathematical models were developed to represent the kinetics of volume changes of fluid spaces associated with infusion of Ringer’s solution. During infusion of Ringer’s solution, the human body is assumed to be characterized by the two-fluid space model which has second volume space in addition to the first volume so that fluid exchanges between these two spaces are possible. Various infusion types were tested to accommodate different medical situations. Volunteers were given Ringer’s solution and the changes in blood hemoglobin were detected. From the comparison with experimental data, the two-fluid space model was found to represent adequately the kinetics of human volume expansion during infusion of Ringer’s solution.     

Novel interactions of caffeic acid with different hemoglobins: Effects on discoloration and lipid oxidation in different washed muscles

Caffeic acid (CA) accelerated methemoglobin (Hb) formation at pH 5.8 and 25 °C. This was attributed to electron donation from CA to liganded O₂ in Hb. CA inhibited hemin dissociation from metHb. Pig Hb remained mostly as oxyHb and did not promote lipid oxidation in washed cod muscle (WCM) nor washed turkey muscle (WTM) during iced storage at pH 5.8. Conversely, perch Hb rapidly was converted to metHb and readily promoted lipid oxidation based on lipid peroxide and hexanal formation. CA strongly inhibited perch Hb-mediated lipid oxidation during storage. Once metHb formation occurred in WCM, CA appeared to maintain the heme protein as metHb during the remainder of iced storage. CA may have become bound to perch Hb based on filtration analysis. CA facilitated the transfer of perch Hb (but not pig Hb) from the aqueous phase to the insoluble components of WCM. Collectively, these results suggest that CA inhibited Hb-mediated lipid oxidation by various mechanisms not related to inhibition of metHb formation.     

基于独立色素浓度分布的皮损图像分割

皮损图像分割是基于皮肤镜的辅助诊断系统的关键。与现有基于纹理或颜色的传统特征进行分割的方法不同,本文提出了一种基于独立色素浓度分布的分割方法。首先基于Lambert-Beer定律建立皮肤镜成像模型,利用独立成分分析方法获得色素浓度分布,并进行可视化显示。把独立色素浓度的比值定义为色素浓度比,该值强化了单一色素浓度在空间的梯度分布。最后,在色素浓度比图上使用全局或局部二值化算法获得最终分割效果。实验证明,本文算法具有很好的鲁棒性和通用性,即使原图中皮损区域梯度不明显,也能获得很好的分割效果。     

Characterization of Hemoglobin Adducts of 1,3-Dinitrobenzene and 1,3,5-Trinitrobenzene

1,3-dinitrobenzene (DNB) and 1,3,5-trinitrobenzene (TNB) are used primarily in explosive compositions and munitions and have been detected as environmental contaminants of surface waters as well as ground waters near production waste disposal sites. Hemoglobin (Hb) adducts have recently been proposed as biological markers of exposure assessment for various environmental compounds, including nitroaromatics. In the present study, we have investigated the formation of DNB and TNB hemoglobin adducts in vivo and in vitro in the blood of shrew (Cryptotis parva). DNB and TNB hemoglobin adducts were detected by GC/MS after either basic (0.1N NaOH) or acid (2N HCl) hydrolysis followed by organic solvent extraction and derivatization of the corresponding amines. The levels of DNB-Hb adducts detected after basic hydrolysis (238.7 ± 50.2 pg/mg Hb) are higher than the corresponding levels detected after acid hydrolysis (52.5 ± 16.2 pg/mg Hb). For the TNB-Hb the levels after acid hydrolysis (132.2 ± 37.8 pg/mg Hb) are higher than the levels detected after basic hydrolysis (44.7 ± 15.3 pg/mg Hb.) These results demonstrate the effectiveness of the hemoglobin adduct model for monitoring exposure to nitroaromatics.     

低Hb水平对AMI患者短期预后的影响

目的了解血红蛋白水平对急性心肌梗死(AMI)患者短期预后的影响。方法回顾性分析兰州大学第二医院1998年1月至2007年1月因AMI入院的临床资料,依据入院时患者血红蛋白水平分为二组:血红蛋白水平≤100g/L组195例,血红蛋白水平>100g/L组1256例,研究的主要终点是30d死亡率。结果二组患者30d总死亡率为11.7%,血红蛋白水平≤100g/L组有37例死亡(19.0%),其死亡率比血红蛋白水平>100g/L组明显增高(133例死亡,10.6%,P<0.001)。多元逻辑回归分析显示:当对其它因素校正后,低血红蛋白水平仍是30d死亡的独立预测因素(HR1.86,CI1.12～2.96;P=0.02)。结论低血红蛋白水平与急性心肌梗死30d死亡明显相关,可作为判断预后不良的指标,应考虑对这些患者采取特殊治疗策略。     

Immobilization, direct electrochemistry and electrocatalysis of hemoglobin on colloidal silver nanoparticles-chitosan film

This paper reports on the fabrication and characterization of hemoglobin (Hb)-colloidal silver nanoparticles (CSNs)-chitosan film on the glassy carbon electrode and its application on electrochemical biosensing. CSNs could greatly enhance the electron transfer reactivity of Hb as a bridge. In the phosphate buffer solution with pH value of 7.0, Hb showed a pair of well-defined redox peaks with the formal potential (E^0′) of −0.325 V (vs. SCE). The immobilized Hb in the film maintained its biological activity, showing a surface-controlled process with the heterogeneous electron transfer rate constant (k_s) of 1.83 s⁻¹ and displayed the same features of a peroxidase in the electrocatalytic reduction of oxygen and hydrogen peroxide (H₂O₂). The linear range for the determination of H₂O₂ was from 0.75 μM to 0.216 mM with a detection limit of 0.5 μM (S/N = 3). Such a simple assemble method could offer a promising platform for further study on the direct electrochemistry of other redox proteins and the development of the third-generation electrochemical biosensors.     

A hydrogen peroxide sensor based on the peroxidase activity of hemoglobin immobilized on gold nanoparticles-modified ITO electrode

A novel ITO electrode surface modified with spherical and rod-shaped gold nanoparticles was prepared by a surfactant-assisted seeding growth approach, which provided a biocompatible matrix for the immobilization of hemoglobin (Hb). By electrochemical impedance measurements, gold nanoparticles modification and Hb immobilization on the electrode surfaces were characterized using [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ redox probe. Owing to the promoted electron transfer of Hb by gold nanoparticles, the Hb immobilized gold nanoparticles-modified ITO (Hb/Au/ITO) electrode exhibited an effective catalytic response to the reduction of H₂O₂ with good reproducibility and stability. The linear relationship existed between the catalytic current and the H₂O₂ concentration in the range of 1 × 10⁻⁵ to 7 × 10⁻³ M. The detection limit (S/N = 3) was 4.5 × 10⁻⁶ M.     

Direct electrochemistry of hemoglobin in biomembrane-like DHP-PDDA polyion-surfactant composite films

Hb-DHP-PDDA films were assembled by incorporating hemoglobin (Hb) into polyion-surfactant DHP-PDDA composite films on pyrolytic graphite (PG) electrodes, where DHP is an anionic surfactant dihexa decylphosphate, and PDDA is a polycation poly(diallyldimethylammonium). Cyclic voltammetry of Hb-DHP-PDDA films showed a pair of stable and reversible peaks for Hb Fe(III)/Fe(II) redox couple at about −0.34 V versus saturated calomel electrode (SCE) in pH 7.0 buffers. The electron transfer rate between Hb and PG electrodes was greatly facilitated in microenvironment of the films. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) suggest that in both DHP-PDDA and Hb-DHP-PDDA films, DHP is self-assembled into an ordered bilayer structure which is sandwiched by PDDA backbone layers. Positions of Soret absorption band indicate that Hb keeps its secondary structure similar to its native state in the films in the medium pH range. Hb could act as an enzymatic catalyst in DHP-PDDA films to catalyze reduction of oxygen, trichloroacetic acid, and nitrite with significant decrease of overpotential.     

Layered double hydroxides functionalized with anionic surfactant: Direct electrochemistry and electrocatalysis of hemoglobin

Direct electrochemistry of hemoglobin (Hb), which was immobilized on the glass carbon electrode (GCE) modified with Zn-Al layered double hydroxide (LDH) functionalized with sodium dodecylsulfonate (SDS), was investigated. The resulting electrode (Hb/LDH-SDS/GCE) gave a well-defined redox couple for HbFe(III)/Fe(II) with a formal potential of about −0.34 V (vs. AgCl/Ag) in pH 7.0 buffer. The electron-transfer rate constant was estimated to be 2.6 s⁻¹. The Hb/LDH-SDS/GCE exhibited a remarkable electrocatalytic activity for the reduction of hydrogen peroxide (H₂O₂). The low calculated apparent Michaelis-Menten constant () was 456 μM. Based on the high catalytic activity of Hb immobilized on LDH-SDS modified electrode to the reduction of H₂O₂, LDH functionalized with SDS is expected to have widely potential applications for development of new biosensors and biocatalysis.