The relative motion of a tetramethylammonium (CH3)(4)N+ ion with respect to a Gd3+ octoaqua complex, together with the quantum dynamics of the electronic spin of this lanthanide, is probed by the nuclear magnetic relaxation dispersion (NMRD) of the (CH3)(4)N+ proton spins. The measured proton resonance frequencies range between 10 and 800 MHz, A pronounced maximum is observed at around 90 MHz. This behavior is interpreted by assuming that the relative diffusion of (CH3)(4)N+ and Gd(D2O)(8)(3+) accounts for their repulsive potential of mean force, calculated with the help of the hypernetted chain approximation for two charged hard spheres in discrete, polar, and polarizable water, and by using a detailed picture of the Gd3+ electronic relaxation, based on an independent electronic paramagnetic resonance study. The standard dipolar nuclear relaxation formalism of Solomon-Bloembergen, valid for the above frequencies, leads to overall good agreement with the experimental data without any adjustable parameters. NMRD experiments using probe solutes of well-known spatial dynamics with respect to a Gd3+ complex, can be combined with the Solomon-Bloembergen theory to provide an indirect estimate of the longitudinal electronic relaxation time of this complex. This knowledge is useful in the theory of magnetic resonance imaging relaxivity.

We investigate the NMR relaxation of solvent nuclei in non viscous paramagnetic solutions, in the case where the electronic spin of the paramagnetic species is submitted to an internal hyperfine field H-hyp. General expressions of the intermolecular longitudinal relaxation rates 1/T-1 are provided, and three distinct regimes corresponding to an applied external field lower, larger and much larger than H-hyp appear, with three distinct linear laws for the relaxation rate 1/T-1 vs v(1)(1/2) ,, where vl is the nuclear resonance frequency. From each of these laws and mainly the third one, it is possible to derive the relative diffusion constant of the paramagnetic and solvent molecules without any model assumption for solutions with a rather high radical concentration of 10(-1) mol L-1. This is illustrated for a triglyme solution with new stable (NTMIOD)-N-15 free radicals at various concentrations. For this solution, T-1 measurements were performed at v(1) = 244 MHz, then at low and intermediate frequencies by the field cycling technique and finally in the Earth's magnetic field. From these results and from measurements of the solvent molecule diffusion constant by the pulsed magnetic field gradient technique, a determination of the diffusion constant of the free radicals is obtained which is compared with that obtained from a direct ESR measurement at low concentration. These data are used for the interpretation of the frequency and temperature dependence of the relaxation rates in this solution.

We present the results of a double-blind trial comparing the efficacy of betamethasone phosphate 0.1%, clobetasone butyrate 0.1%, and placebo in the treatment of acute unilateral nongranulomatous uveitis. The 2 steroids were equally comparable in improvement of the patients' symptoms, though betamethasone phosphate was significantly more effective than clobetasone butyrate in improving the ocular signs of uveitis. However, clobetasone butyrate had significantly less effect on raising intraocular pressure in known steroid responders and ocular hypertensives than did dexamethasone. The use of a bolometer as an objective measure in uveitis was significant only in the more severe cases of uveitis. In comparing the placebo group of patients with those on topical steroids, the former group, though improving, appeared to lag behind by approximately one week. Four cases on placebo, however, had to be withdrawn because of worsening of the condition. Mild cases of anterior uveitis would probably resolve without using topical steroids.

The results are presented of a double-blind trial comparing the efficacy of betamethasone phosphate 0.1 per cent, clobetasone butyrate 0.1 per cent, and placebo in the treatment of acute unilateral non-granulomatous uveitis. The two steroids gave comparable results in improvement of the patients' symptoms, although betamethasone phosphate was significantly more effective than clobetasone butyrate in improving the ocular signs of uveitis. In comparing the placebo group of patients with those given topical steroids, the former group, though improving, appeared to lag behind by approximately 1 week. Four patients receiving placebo, however, had to be withdrawn because of worsening of the condition. Mild cases of anterior uveitis would probably resolve without using topical steroids.