Clinical phase I and pharmacology study of gemcitabine (2', 2'-difluorodeoxycytidine) administered in a two-weekly schedule.

Gemcitabine (dFdC) was tested in a Phase I trial at 14 doses (40-5700 mg/m(2)), administered every 2 weeks as a (1/2) -h infusion to 52 patients with refractory solid cancer. Gemcitabine and its deaminated metabolite difluorodeoxyuridine (dFdU), measured with HPLC, reached plasma peak levels of 2-3 microM at 40 mg/m(2) which increased to 512 microM at 5700 mg/m(2). Gemcitabine was eliminated rapidly with a t(1/2) beta of 2.

Quantitative T2 imaging of plant tissues by means of multi-echo MRI microscopy.

A method for quantitative T2 imaging is presented which covers the large range of T2 values in plants (5 to 2000 ms) simultaneously. The transverse relaxation is characterized by phase-sensitive measurement of many echo images in a multi-echo magnetic resonance imaging sequence. Up to 1000 signal-containing echo images can be measured with an inter-echo time of 2.

Quantitative 1H-NMR imaging of water in white button mushrooms (Agaricus bisporus).

MRI represents a valuable tool for studying the amount and physical status of water in plants and agricultural products, for example, mushrooms (Agaricus bisporus). Contrast in NMR images originates from the mixed influence of the fundamental NMR parameters, amongst others, spin-density, T2- and T1 relaxation processes. Maps of these parameters contain valuable anatomical and physiological information.

NMR imaging of white button mushroom (Agaricus bisporis) at various magnetic fields.

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) have been applied to visualize physiological phenomena in plants and agricultural crops. Imaging sequences that result in contrast of a combination of parameters (e.g.

Determination of the antimetabolite Gemcitabine (2',2'-difluoro-2'-deoxycytidine) and of 2',2'-difluoro-2'-deoxyuridine by 19F nuclear magnetic resonance spectroscopy.

The analysis of the new antimetabolite 2',2'-difluoro-2'-deoxycytidine (Gemcitabine, Eli Lilly Corp.) and of its metabolic deamination product, 2',2'-difluoro-2'-deoxyuridine, in urine and plasma by means of 19F NMR is described. Both compounds show AB-type NMR spectra which are characterized as a function of pH at a magnetic field strength of 9.