Polyenoylphosphatidylcholine (PPC: 100 or 300 mg kg-1 b.w., by gastric intubation for 30 days) produced a clearcut protection of the liver of rats treated with alloxan (150 mg kg-1 b.w., i.p.). The liver of rats treated with alloxan was characterized by hydropic dystrophy and lymphocytic infiltrations. Treatment with alloxan increased serum gamma-GT and ALAT activities. The liver structure of rats treated with PPC did not differ from the liver of control animals. PPC normalized the biochemical abnormalities caused by the diabetes. The number of pancreatic islets and beta/alpha cell ratio decreased in the diabetic rats. A number of beta-cells in this group did not contain granules. PPC prevented the decrease in the number of islets and the beta/alpha cell ratio in the pancreas of the diabetic rats. The intensity of staining of beta-cell granules in the pancreas of PPC-treated rats had a position intermediate between the control and diabetic groups. Alloxan increased the blood glucose content where treatment with PPC decreased this. The results suggest that PPC acts as a cytoprotector in the liver and pancreas of rats with experimental diabetes induced by alloxan.

Dynamic structural analysis of the molecules possessing large-amplitude degrees of freedom has been attempted by many researchers; however, so far, electron diffraction investigations involved only one large-amplitude coordinate (internal rotation or bending). The current state of computational facilities allows extending of the general dynamic approach to the systems possessing two or more large-amplitude motions. This paper presents the first practical implementation of the theoretical method developed previously by the authors for solving the dynamic-structural problem with two or more large-amplitude coordinates; the procedure is applied to a molecule of 3-nitrostyrene. The molecule is represented as a set of pseudoconformers built on a two-dimensional grid corresponding to both internal rotation coordinates present in the molecule (with 10-30° steps by each angle); altogether, up to 342 pseudoconformers were used. Structural analysis was based on the experimental electron diffraction data supported by quantum chemical calculations (at the MP2 and B3LYP levels of theory) and molecular spectroscopy data. Quantum chemistry predicts the planar structure of both syn- and anti- stable conformations with close energies and weak interaction between internal rotations of nitro and vinyl groups. The gas-phase electron diffraction experimental data are compatible with the quantum chemical predictions. The principal equilibrium geometry parameters of the molecule (syn- conformation) have been determined as follows: r(e)(C-C)(ring, avg.) = 1.391(1) Å, r(e)(C-C) = 1.477(5) Å, r(e)(C═C) = 1.333(7) Å, r(e)(C-N) = 1.463(5) Å, r(e)(N═O) = 1.227(3) Å, ∠e(O═N═O) = 124.3 (4)°. Experimental data for this molecule are insufficient to make estimates of the barrier heights of internal rotation; the population ratio of syn- and anti- conformations is evaluated as 50 ± 20%. Results of our investigation confirm the presence of significant internal rotations in the 3-nitrostyrene molecule.

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