PubMed · 11468367
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G D Rose. 2001. Perspective.. https://doi.org/10.1002/pro.101691
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The influence of the morphology of ethylene glycol dimethacrylate-hydroxyethyl methacrylate copolymer [poly(EGDMA-co-HEMA)] base support to obtain different Fe(3+)-containing sorbents and their properties in retention of O-phosphothreonine [Thre(P)] is examined in this paper. Three base supports poly(EGDMA-co-HEMA) (I-III) were obtained using different quantities of initiator in suspension polymerization reactions. These products were submitted to chemical modifications using 1,4-butanediol diglycidyl ether (BDGE) in activation reactions and different chelating agents (iminodiacetic acid, IDA; disodium ethylenediamine tetraacetate, EDTA; and hexamethylenediamine tetrapropanoic acid, HMDTP) in coupling reactions to attain Fe(3+)-containing sorbents. Properties such as specific surface area (S(s)), specific pore volume (V(p)), scanning electron microscopy (SEM), IR spectroscopy, quantity of functional groups (oxirane and carboxyl), amount of chelated metal ion, ligand occupation (L), swelling studies as well as quantity of O-phosphoamino acid retained were used as comparative parameters for matrices. In general, the derivatization reactions proved to be more efficient when higher S(s) of macropores (50-400,000 nm) were available in the matrix. In our case, it was observed when highest percentage of initiator was used. On the other hand, the effect of accessibility of surface area on the yield of coupling reactions was noticed when comparing the different chelating agents since the number of carboxyl groups present in products was higher when the molecular size of the chelating agent was lower. Although all Fe(3+)-containing sorbents resulted efficient to retain Thre(P), the values of retention of the amino acid were slightly higher when IDA-containing matrices were used irrespective of the quantity of metal chelated. This could be probably due to the fact that the IDA ligand could be bounded to the matrix in sites that though accessible for the center of adsorption were hard for Thre(P) to access.
Anoxia/hypoxia induces dramatic changes in brain activity leading to the damages in brain structure. Several minutes of decrease in environmental oxygen partial pressure (P(O2)) can irreversibly destroy nerve cells. Therefore, investigations of intracellular mechanisms responsible for hypoxia-induced changes of mammalian nerve system are very important. On-line adjustment and measurements of P(O2) in bath solution during patch-clamp experiments are especially topical. At the recent time, a special interest on the on-line measurements of oxygen contents in bath solution has appeared as a result of application of old approaches previously used for polarographic measurements of oxygen contents in the blood and tissues. Here we describe the simple method of manufacturing oxygen-sensitive microelectrodes, which can be used with standard patch-clamp amplifier. We also describe the main principles of polarographic method and properties of oxygen-sensitive electrodes used in patch-clamp experiments.
The identification and characterization of proteins in complex biological samples such as body fluids, require powerful and reliable tools. Mass spectrometry is today one of the most important methods in such research. This paper reports on the results from the first experiment where a tryptic digest of cerebrospinal fluid was analyzed applying reversed phase liquid chromatography coupled on-line to a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer. In total, 70 204 peaks were detected, which originated from 16 296 isotopic clusters corresponding to 6551 unique peptide masses. From these masses, 39 proteins were identified in the sample. The amount of sample required for one experiment corresponds to 32 microL of cerebrospinal fluid.