Comparative ¹H NMR studies of saturation transfer in copolymer gels and mouse lenses

Abstract

Saturation transfer in cross-linked copolymer gels and excised intact and perforating trauma-induced cataract mouse lenses (4- or 8-week-old) were studied using intermolecular cross-relaxation rates (1/T(IS)(H(2)O); 1/T(IS)), monitored with f(2)-irradiation at -8.79, -4.00, and 7.13 ppm (gammaH(2)/2pi approximately 69 Hz). [1] The 1/T(IS)(7.13 ppm) vs dry weight [W (%)] profiles for hydrophilic copolymer gels were far steeper than those for hydrophobic copolymer gels, indicating the participation of an amount of bound water and a number of copolymer hydroxyl groups in the saturation transfer process. In contrast, the 1/T(IS)(-8.79 ppm) vs W (%) profiles exhibited little difference between the hydrophilic and hydrophobic copolymer gels, indicating the major participation of molecular rigidity, i.e. W (%) in the saturation transfer process. [2] The 1/T(IS)(7.13 ppm) values for cataractous mouse lenses were larger than those for intact lenses, indicating the formation of large, immobile lens protein associates or aggregates containing a sufficient amount of bound water for the saturation transfer. [3] The 1/T(IS)(7.13 ppm) vs W (%) profiles for the hydrophilic copolymer gels exhibited similar characteristics to the intact and cataractous mouse lenses with regard to the saturation transfer process.

Comparative intermolecular cross‐relaxation studies of human hemoglobin in red blood cells and bovine serum albumin in solution

“…Before discussing the CR spectra of RBCs, we explain CR and CR ratio vs f 2 (ppm) profiles for hydrophilic and hydrophobic copolymer gels, as models for tissue (46,47 fig. 5C therein).…”

“…The open end of each hematocrit capillary (packed RBCs) was sealed with inert plastic paste and inserted into a glass capillary with an inner diameter of 1.1 mm. The open end of the glass capillary was also sealed, and the glass capillary was inserted into a 5-mm w co-axial NMR tube containing a small amount of dimethylsulfoxide-d 6 (CEA, Cedex, France) for locking (21,38,46,47).…”

“…Intra-and intermolecular cross-relaxation rates from irradiated protein protons to observed protein and water protons have been introduced recently (29)(30)(31)(32)(33)(34) and applied to elucidate protein-protein, protein-water (21,(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46) and polymer-water (38,(46)(47)(48)(49)(50) interactions. The CRs 1 from irradiated biopolymer protons in tissues to observed water protons have been studied extensively by many groups.…”