Mathematical modeling the kinetics of cell distribution in the process of ligand-receptor binding

A statistical approach is presented to model the kinetics of cell distribution in the process of ligand-receptor binding on cell surfaces. The approach takes into account the variation of the amount of receptors on cells assuming the homogeneity of monovalent binding sites and ligand molecules. The analytical expressions for the kinetics of cell distribution have been derived in the reaction-limited approximation. In order to demonstrate the applicability of the mathematical model, the kinetics of binding the rabbit, anti-mouse IgG with Ig-receptors of the murine hybridoma cells has been measured. Anti-mouse IgG was labeled with fluorescein isothiocyanate (FITC). The kinetics of cell distribution on ligand-receptor complexes was observed during the reaction process by real-time measuring of the fluorescence and light-scattering traces of individual cells with the scanning flow cytometer. The experimental data were fitted by the mathematical model in order to obtain the binding rate constant and the initial cell distribution on the amount of receptors.     

Morphology and Antigenic Properties of Recombinant Analogs of the Marburg Virus Nucleoprotein

The full-length gene for Marburg virus (MV) nucleoprotein (NP) was cloned in prokaryotic pQE32 under the control of the T5 promoter and in eukaryotic pTM1 under the control of the T7 RNA polymerase promoter. Recombinant NP was synthesized in Escherichia coliand in human kidney cell line 293 cotransfected with recombinant vaccinia virus vTF7-3 expressing T7 RNA polymerase. On evidence of electron microscopy with immune detection, recombinant NP formed tubules of two types in E. coliand of a single type in cell line 293. ELISA and immunoblotting with polyclonal and monoclonal antibodies revealed common antigenic determinants in recombinant NP and natural MV NP.     

Virotherapy of the Malignant U87 Human Glioblastoma in the Orthotopic Xenotransplantation Mouse SCID Model

The possibility of glioblastoma virotherapy at intravenous injection of the LIVP–GFP recombinant virus was studied in experimental model of orthotopic xenotransplantation of human glioblastoma cell line U87 to SCID laboratory mice. The LIVP–GFP recombinant virus deficient for thymidine kinase exhibited a significantly greater oncolytic capacity than the original LIVP virus, and an intravenous injection of LIVP–GFP at the early stages of tumorigenesis in mouse brain in most cases resulted in the lysis of the tumor.     

Variability of ceftazidime pharmacokinetics in children with suppurative-septic diseases

Marked variability of the ceftazidime pharmacokinetics (Cmax and T1/2) was observed in 3 newborns and 2 infants with purulent septic infections. The patients were under complex treatment in a reanimation unit (artificial pulmonary ventilation, infusions). It was recommended to perform the treatment with monitoring the antibiotic plasma concentrations to prevent the drug failure because of the changes in the distribution and excretion patterns. The use of HPLC for the purpose is advisable.     

Antiviral activity of aqueous extracts and polysaccharide fractions from mycelium and fruit bodies of higher fungi

Sixty preparations of basidiomycetes (Ganoderma, Lentinus, Pleurotus, Laetiporus, Polyporus, Inonotus, Flammulina, Grifola, Trametes) were investigated with respect to their toxicity for Vero cells and antiviral activity. The antiviral activity was estimated with the use of the West Nile virus and type 2 Herpes simplex. It was shown that 11 preparations of Ganoderma, Lentinus and Pleurotus completely inhibited the infective activity in doses not lower than 1000 TCD50 (the West Nile virus) and 100 PPU (type 2 Herpes simplex). The antiviral activity of the preparations was likely due to the content of polysaccharides or their derivatives in the composition. It increased with increasing of the quantity of the total polysaccharide fraction or its concentration.     

Effect of temporary hypovolemia on the early central pooling of the blood circulation following resuscitation and the survival of animals experiencing clinical death

The experiments were conducted on cats under pentobarbitone sodium anesthesia (40 mg/kg). The effect of 30-min hypovolemia (Wiggerse's model, 13.3 kPa or 100 mm Hg) on the cardiac output, its main fractions and the survival of animals recovered after clinical death (5 min) were studied. Hypovolemia was induced after cardiac contractions were recovered. In experimental (19 cats) and control (23 cats) studies clinical death was caused by arterial blood loss. The animals had been previously subject to hemorrhagic hypotension (according to Wiggerse, 6.7 kPa or 50 mm Hg, for 30 minutes). Temporary exclusion of part of blood volume from the circulation was found to abolish the phase of cardiac output increase in the postresuscitation period, attenuate the reaction of blood circulation centralization, improve the course of reparative processes and increase the survival of animals recovered after clinical death.