Efficient in vitro repair of 7-hydro-8-oxodeoxyguanosine by human cell extracts: involvement of multiple pathways

To investigate the repair of oxidative damage in DNA, we have established an in vitro assay utilizing human lymphoblastoid whole cell extracts and plasmid DNA damaged by exposure to methylene blue and visible light. This treatment has been shown to produce predominantly 7-hydro-8-oxodeoxyguanosine (8-oxodG) in double-stranded DNA at low levels of modification. DNA containing 1. 6 lesions per plasmid is substrate for efficient repair synthesis by cell extracts. The incorporation of dGMP is 2.7 +/- 0.5 times greater than the incorporation of dCMP, indicating an average repair patch of 3-4 nucleotides. Damage-specific nicking occurs within 15 min, while resynthesis is slower. The incorporation of dGMP increases linearly, while the incorporation of dCMP exhibits a distinct lag. Extracts from xeroderma pigmentosum (XP) complementation groups A and B exhibit 25 and 40%, respectively, of the incorporation of dCMP compared with normal extracts, but extracts from an XP-D cell line exhibit twice the activity. These data suggest that the efficient repair of 8-oxodG lesions observed in human cell extracts involves more than one pathway of base excision repair.     

Particularities of the electroplating process in the case of a single-phase power supply with an embedded induction-capacitance device

This paper presents experimental data on the use of a single-phase power supply and induction-capacitance device for copper electroplating. It is shown that the electrode potential and deposit structure depend on the values of the induction and capacitance through the influence of alternating components.     

Bias in risk-benefit analysis

Risk-benefit analysis has become popular in the past decade as a means of improving decision-making, especially in the area of technology policy. Here risk-benefit analysis is compared to other (equally defensible) approaches to decision-making, showing how it favors some political interests more than others, and suggesting why it has recently come to the fore as a tool of politicaL analysis.     

Homogenization of viscose under the action of an alternating electromagnetic field

Conclusions A method of homogenizing viscose using an alternating electromagnetic field has been suggested.Homogenization of viscose by this method is advisably carried out at an alternating field strength of 50 kA/m, immediately before spinning on the spinning machine.Translated from Khimicheskie Volokna, No. 6, pp. 33–34, November–December, 1988.     

Hepatic apolipoprotein and LDL receptor gene expression in the genetically hypercholesterolemic (RICO) rat

Up and down-regulation of calcium and potassium conductances are associated with several forms of short-term synaptic modulation. Detailed investigation of synaptic plasticity in the marine gastropod Aplysia, and in other mollusks, indicates that synaptic transmission can be influenced in a number of ways by modulatory neurotransmitters acting through several second-messenger cascades. Modulation at the synapse itself occurs by means of the regulation of calcium current as well as through effects on processes directly involved in transmitter mobilization and exocytosis. Modulation of potassium current plays a major role in controlling neuronal excitability and may contribute to a lesser extent to the regulation of transmitter release through actions on the resting potential and on action potential configuration.