The molecular mechanism of interaction of trivalent dimethylarsinous acid (DMA(III)) binding to rat hemoglobin / 药学学报

In our previous work, we found that trivalent dimethylarsinous acid (DMA(III)) have high affinity binding to cysteine residue 13 of rat hemoglobin. However, it is still unknown why arsenic intermediate metabolite DMA(III) has high binding affinity for Cysl3 but not for other cysteine residues 93, 140, 111 and 125. In order to better understand the molecular mechanism of DMA(III) with rat hemoglobin, we have done current study. So, SD rats were divided into control and arsenic-treated groups randomly. Arsenic species in lysate of red blood cells were analyzed by HPLC-ICP-MS, and then determined by a hybrid quadrupole TOF MS. In addition, trivalent DMA(III) binds to different cysteine residues in rat hemoglobin alpha and beta chains were also simulated by Molecular Docking. Only Cys13 in alpha chain is able to bind to DMA(III) from the experiment results. Cys13 of alpha chain in rat hemoglobin is a specific binding site for DMA(III), and we found that amino acids compose pockets structure and surround Cys13 (but not other cysteine residues), make DMA(III) much easy to bind cysteine 13. Taken together, the DMA(III) specific binding to Cys13 is related to spatial structure of Cys13.

Purification of arsenic-binding proteins in hamster plasma after oral administration of arsenite / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To purify the arsenic-binding proteins (As-BP) in hamster plasma after a single oral administration of arsenite (iAs(III)).</p><p><b>METHODS</b>Arsenite was given to hamsters in a single dose. Three types of HPLC columns, size exclusion, gel filtration and anion exchange columns, combined with an inductively coupled argon plasma mass spectrometer (ICP MS) were used to purify the As-BP in hamster plasma. SDS-PAGE was used to confirm the arsenic-binding proteins at each purification step.</p><p><b>RESULTS</b>The three-step purification process successfully separated As-BP from other proteins (ie, arsenic unbound proteins) in hamster plasma. The molecular mass of purified As-BP in plasma was approximately 40-50 kD on SDS-PAGE.</p><p><b>CONCLUSION</b>The three-step purification method is a simple and fast approach to purify the As-BP in plasma samples.</p>

Effect of processing parameters on the degradation of calcium polyphosphate bioceramic for bone tissue scaffolds / 生物医学工程学杂志

This study was undertaken to elucidate the degradation regularity of calcium polyphosphate (CPP) scaffolds with different preparation parameters. CPP scaffolds with different main crystalline phases were prepared by controlling the particle size of the calcining stuff and the calcining heat. Specimens were soaked into Tris-buffer solution and simulated body fluid (SBF) for 60 days. Results show: alpha-CPP degrades faster than does beta-CPP, and beta-CPP degrades faster than does gamma-CPP; the lower the sinter temperature, the better the degradation of CPP morever, the degradation rate of CPP is inversely proportional to the original particle size. These data suggest that crystal type, sinter temperature and particle size influence the degradation rate of CPP markedly.

Development of S2001 field operating table / 医疗卫生装备

To meet the requirements of modern field first-aid operation, a field operating table, which can be wholly folded, is developed in this paper. The table consists of a bracket and a board. The trigonal bracket, with double arms, has an articulated shoring. The posture regulation part is composed of the wormwheel, worm, rocker of plate and shoring fittings of all segments of the table. According to the measurements of its dimensions and posture angle, military experiment, experiments for stability, load, regulation moment and simulate transportation on the third level of road, S2001 field operating table is suitable for the operations on head and cervix, chest and abdomen, limbs, urinary organs and the five sense organs, whose wholly-fold structure contributes to rapid deployment and undeployment in the field.