[Acute amnesic syndrome--patient's disorientation baffles a doctor]

We report a 53-year-old female patient who presented a sudden dramatic memory disorder following coronary and cerebral angiography. The patient was disoriented and kept repeating the same questions about time and place. Transient global amnesia was ultimately diagnosed using the Hodges and Warlow criteria. We briefly discuss how to distinguish transient global amnesia from psychogenic amnesia, transient epileptic amnesia and transient ischemic attack.

Spatial distribution functions as a tool in the analysis of ribonucleic acids hydration--molecular dynamics studies

The spatial distribution functions (SDFs) determined as three-dimensional density distribution of hydrogen and oxygen atoms of water in a local coordinate system linked with RNA molecule are used to study details of the spatial structure of aqueous solution around selected parts of RNA duplexes: r(CGCGCG)2 and 2'-O-Me(CGCGCG)2. The influence of the 2'-O-methylation on the hydration pattern of RNA helical fragments is visualized at the atomic level.

Hydration of C-H groups in natural dithymidine nucleotide and its methylphosphonate analogues

In this paper we report our preliminary studies on the hydration pattern of selected C-H groups in natural thymidyl(3'-5)thymidine and its Rp and Sp-methylphosphonate analogues using Molecular Dynamic simulations in aqueous solutions. The methyl groups attached to the phosphorus center (P-Me) in methylphosphonate analogues are hydrated by water molecules as efficiently as the hydrophilic P=O group in the natural dithymidine nucleotide and better than the neutral P=O functions in these compounds, although the nature of the hydration is different. The C5-Me centers of the 3'-yl units seem to be better hydrated in the methylphosphonate analogues than in the natural dithymidine phosphate and than other centers of the thymine bases in methylphosphonate analogues. Due to chirality of the phosphorus center, the C5-Me group of the 5'-yl unit in the Sp diastereomer coordinates more water than that in the Rp diastereomer. The C6-H group in the 5'-yl unit of the Sp diastereomer exhibits a specific interaction with water.

Hydration of C-H groups in natural dithymidine nucleotide and its methylphosphonate analogues

In this paper we report our preliminary studies on the hydration pattern of selected C-H groups in natural thymidyl(3'-5)thymidine and its Rp and Sp-methylphosphonate analogues using Molecular Dynamic simulations in aqueous solutions. The methyl groups attached to the phosphorus center (P-Me) in methylphosphonate analogues are hydrated by water molecules as efficiently as the hydrophilic P=O group in the natural dithymidine nucleotide and better than the neutral P=O functions in these compounds, although the nature of the hydration is different. The C5-Me centers of the 3'-yl units seem to be better hydrated in the methylphosphonate analogues than in the natural dithymidine phosphate and than other centers of the thymine bases in methylphosphonate analogues. Due to chirality of the phosphorus center, the C5-Me group of the 5'-yl unit in the Sp diastereomer coordinates more water than that in the Rp diastereomer. The C6-H group in the 5'-yl unit of the Sp diastereomer exhibits a specific interaction with water.

A comparative study on the dynamics of epimeric 1-hydroxymethyl quinolizidines: II. The solvent and concentration dependence of the association properties

The homo and heteroassociation patterns of lupinine and epilupinine in different solvents and at various concentrations have been studied. In n-hexane, n-heptane, CCl4, and C2H4Cl2 solvents, lupinine monomers with an intramolecular OH … N hydrogen bond dominate over homoassociates with an OH … O′ intermolecular hydrogen bond even in concentrated solutions. Homoassociation of lupinine by intermolecular OH … N′ hydrogen bonding is observed only in saturated solutions. In chloroform solution any intermolecular homoassociation is effectively blocked because of significant affinity of chloroform molecules acting as a weak acid toward the free electron pairs of the oxygen atom from the hydroxyl group that would be otherwise engaged in intramolecular OH … N hydrogen bonding. Epilupinine in n-hexane, n-heptane, CCl4, C2H4Cl2, and chloroform solutions forms possible homoassociates both by OH … N′ and OH … O′ intermolecular hydrogen bonding. In dioxane-d8, DMSO, and D2O solvents both lupinine and epilupinine form heteroassociates with solvent molecules.

A comparative study on the dynamics of epimeric 1-hydroxymethylquinolizidines: I. Conformational analysis of monomers and spectroscopic data for solid state, liquid state, and dilute solutions

A systematic comparative study of the conformational dynamics of lupinine and epilupinine, two 1-hydroxymethyl quinolizidine epimers, as a function of phase transition and of their protonation is presented. Lupinine and epilupinine have a trans-quinolizidine configuration and they differ only in the position of the CH2OH group. The axial position of this group allows the formation of an intramolecular hydrogen bond OH … N in lupinine, in contrast to epilupinine in which this group is in the equatorial position. Intrinsic conformational equilibria for both epimers have been defined. Despite the significant difference in the population of the preferred rotamers of lupinine and epilupinine, both epimers adopt very similar crystal structures, but in all other states and forms, e.g., pure liquids, solutions in inert and polar solvents, and protonated salts, they behave in drastically different ways.

Interaction of alkaloids with plant transfer ribonucleic acids. Effect of sparteine on lupin arginyl-tRNA formation

The effect of the alkaloid sparteine on arginyl-tRNA formation was studied. It was demonstrated that sparteine sulfate in the concentration range 10-60 mM inhibits the charging reaction when amino acid, ATP and tRNA are used as variable substrates. The mode of action is different for all pattern of inhibition for all varied substrates is generally uncompetitive. A pattern of inhibition for all varied substrates is generally uncompetitive. A non-competitive mechanism for amino acid and tRNA was observed at low sparteine concentration, but in the case of ATP it is also uncompetitive.