Towards a Systemic Concept of the Brain Ishemia Stroke: Monte Carlo Driven Model.

Background: The work proposes a new mathematical model of dynamic processes of a typical spatially heterogeneous biological system, and sets and solves a mathematical problem of modeling the dynamics of the system of neurovascular units of the brain in conditions of ischemic stroke. There is a description of only a small number of mathematical models of stroke in the literature. This model is being studied and a numerical and software implementation of the corresponding mathematical problem is proposed.

Purine nucleoside phosphorylase: inhibition by purine N(7)- and N(9)-acyclonucleosides; and substrate properties of 7-beta-D-ribofuranosylguanine and 7-beta-D-ribofuranosylhypoxanthine.

A series of 10 N(7)- and N(9)-acyclonucleosides of guanine and 8-substituted guanines (8-Br, 8-SH and 8-NH2), and two N(7)-acyclonucleosides of hypoxanthine, were tested for their ability to inhibit purine nucleoside phosphorylase (PNP) (E.C. 2.

Relationship between the electronic structure and biological activity of inhibitors of purine nucleoside phosphorylase: 1. Acyclonucleosides of guanine and hypoxanthine.

The electronic and conformational properties of some acyclonucleosides of guanine and hypoxanthine were studied by the modified intermediate neglect of differential overlap (MINDO/3) molecular orbital method. There is a significant linear relationship between the ionization potentials of these compounds and their inhibitory effect on purine nucleoside phosphorylase, a key enzyme in purine metabolism.