Interaction of multicomponent anionic liposomes with cationic pyridylphenylene dendrimer: Does the complex behavior depend on the liposome composition?

Dendrimers are individual macromolecular compounds having a great potential for biomedical application. The key step of the cell penetration by dendrimers is the interaction with lipid bilayer. Here, the interaction between cationic pyridylphenylene dendrimer of third generation (D350+) and multicomponent liquid (CL/POPC), solid (CL/DPPC) and cholesterol-containing (CL/POPC/30% Chol) anionic liposomes was investigated by dynamic light scattering, fluorescence spectroscopy, conductometry, calorimetric studies and molecular dynamic (MD) simulations. Microelectrophoresis and MD simulations revealed the interaction is electrostatic and reversible with only part of pyridinium groups of dendrimers involved in binding with liposomes. The ability of dendrimer molecules to migrate between liposomes was discovered by the labeling liposomes with Rhodamine B. The phase state of the lipid membrane and the incorporation of cholesterol into the lipid bilayer were found to not affect the mechanism of the dendrimer - liposome complex formation. Rigid dendrimer adsorption on liposomal surface does not induce the formation of significant defects in the lipid membrane pave the way for possible biological application of pyridylphenylene dendrimers.

[The etiological structure of acute viral hepatitis in Tadzhikistan in a period of decreased morbidity]. / Etiologicheskaia struktura ostrykh virusnykh gepatitov v Tadzhikistane v period snizheniia zabolevaemosti.

In the period of reduced incidence of viral hepatitis in Tajikistan, January-December, 1990, 1562 patients with acute viral hepatitis (AVH) were examined in the first days of the jaundice phase (928 children under 14 years and 634 adults) in Dushanbe. Markers of hepatitis A, B, and D (HBsAg, anti-HA IgM, anti-HBc IgM, anti-delta IgM) were determined by enzyme immunoassay. Hepatitis A occurred in 25.8% of the patients with AVH, mostly children of 1-6 years, HB in 22.8%, HD co- and superinfection) in 9.2%. In 42.1% of the patients who had no HA, HB, or HD markers in the blood, non-A, non-B hepatitis (mostly hepatitis E) was diagnosed, mainly in the age groups of 30-39 years (70.7%) and 15-29 years (59.2%). Thus, in Tajikistan hepatitis E occurs not only during outbreaks of this infection but also sporadically.