Ultraviolet light-induced free radical alkylation with 2-propanol or D-ribose, initiated with di-tert-butyl peroxide, of poly (G), poly (U20G), and poly(A) led to the substitution of the appropriate group for the H-8 atom of the purines and addition across the 5,6-double bond of the pyrimidines. The alkylated polynucleotides were subjected to nucleolytic digestion with several nucleases. T1-RNa...

The binding of lactose repressor to poly d(A-T) at low ionic strength has been investigated by heat denaturation. The poly d(A-T) melting is monitored by optical density and the protein melting by circular dichroism. From the modification of the poly d(A-T) melting curve we estimate a maximum binding ratio of about one tetrameric repressor to about 20 basic pairs. The repressor melting can be i...

The mechanism of streptolydigin inhibition of RNA synthesis has been investigated with a combination of steady state kinetics and product analysis by employing the abortive initiation reaction of Escherichia coli RNA polymerase. The pattern of inhibition by streptolydigin on the poly[d(A-T)] . poly[d(A-T)]template (non-competitive versus AMP; competitive versus UTP) was consistent with one inhi...

This study demonstrates that pretreatment with polyinosinic-polycytidylic acid (poly I:C) significantly decreased the mortality and liver injury caused by injection of lipopolysaccharide (LPS) in the presence of d-galactosamine (d-GalN) in C57BL/6 mice. Depletion of natural killer, natural killer T, and T cells did not change the protective effect of poly I:C on LPS/d-GalN-induced liver injury ...

Frothers havea profoundeffectonbubble size and also flotation efficiency. In present study the effect of type and dosage of frothers on the flotation response of coarse particles of quartz was investigated.  Therefore, flotation response of coarse particles using frothers such as MIBC, pine oil, poly propylene glycol with concentration of 0, 25, 50 and 75...

Earlier, we showed that, for the D form (n = 8 and h = 3.03 A, where n is number of nucleotide units per turn and h is height per nucleotide unit) of poly[d(A-T)], both right- and left-handed double helical models are stereochemically satisfactory and give good agreement with the observed fiber diffraction data. It was also noted that the conformations of the right- and left-handed D-DNA models...

membrane permeability and p-glycoprotein (p-gp) efflux system are regulating factors in the drug brain penetration. recently, some drug delivery systems have been developed to overcome these limitations. in this study, metoclopramid has been encapsulated in plga nanoparticles using the emulsification/solvent evaporation technique for in vitro evaluation of the effect of plga nanoparticles on bb...

microspheres formulated from poly (d,l-lactic-co-glycolide) (plga), a biodegradable polymer, have been extensively evaluated as a drug delivery system. in this study, the preparation, characterization and drug release properties of the plga microspheres were evaluated. simvastatin (sim)-loaded plga microspheres were prepared by oil-in-water emulsion/solvent evaporation method. the microspheres ...