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S Edel

Publications and source records attributed to S Edel.

12 recordsLinked to original sources
PubMed2006

Computer simulation of strand break yields in plasmid pBR322: DNA damage following 125I decay.

This paper presents results of (125)I effects on plasmid pBR322 in aqueous solution, simulating the complete transport of Auger and X rays up to the chemical phase. In addition to new sampling algorithms, new electronic cross sections are included. Simulations were carried out both with (125)I, bound to plasmid, or free, in its vicinity. The influence of the hydroxyl radical scavenger dimethyl sulfoxyde (DMSO) has also been tested, underlying that, in naked DNA, double strand breaks (caused by the decay of bound (125)I) are mainly due to direct hits. The calculated yields of relaxation events (RE) and linearization events (LE) show good agreement with experimental ones: when (125)I is bound to the plasmid pBR322, 0.16 RE and 0.83 LE per decay (without DMSO) are then observed. Then, when 2 mol DMSO is added, RE and LE probabilities become 0.22 and 0.76. The very light differences with those from literature could arise from experimental conditions.

Base Pair Mismatch↗
PubMedDate not supplied

Computer evaluation of direct and indirect damage induced by free and DNA-bound iodine-125 in the chromatin fibre.

PURPOSE: When Iodine-125 decays within chromatin, several in vivo experiments have shown that the radiobiological effects are caused mainly by indirect mechanisms and that more than one DNA double strand break (DSB) is produced per decay. We present calculations to evaluate the contribution of direct and indirect effects of radiation tracks to produce DNA damage induced by bound and free I-125 in a model of chromatin DNA. MATERIALS AND METHODS: A solenoid model of chromatin with 18 nucleosomal elements placed in bulk water (more than 600,000 atoms) is used where the initial I-125 decay takes place. All physical and chemical events initiated by Auger and X-rays were taken into account. The yields of single strand breaks (SSB) and DSB were derived using direct effects on DNA and indirect reactions of all radical species generated in the radiolysis of the bulk water. RESULTS: The distribution of damage complexity for free and DNA-bound I-125 is presented. We obtained more than 1.3 DSB per decay, with nearly equal contributions from direct and indirect effects. However, for the most complex type of damage, located at the decay site, the direct effect is about 70% of the total number. To show the protective effect of histones, simulations were carried out with and without the presence of histones.

Chromatin↗
PubMedDate not supplied

[Single compartment Oxford knee prosthesis].

From 1988 to 1992, we implanted 30 Oxford single compartment prostheses. Follow-up was sufficient for study in 27 cases. The Oxford single compartment prosthesis is original because the height of the meniscal component varies with mobility during flexion-extension. This single compartment prosthesis requires a rigorous technique on the basis of well respected fundamental principles. The opposite femorotibial compartment must be untouched, otherwise a slight deviation of the axis may occur. Mobility must be satisfactory and the anterior cruciate ligament must not be injured. In our series, we obtained the same results as published in the literature, particularly those reported by Goodfellow who advocates its use. Results were satisfactory in 89% of the patients. There was an extraordinary improvement in pain symptomatology. There was little improvement in mobility. Overcorrection must be absolutely avoided because of the risk of destroying the opposite compartment. Besides the classical complications which include thrombophlebitis and retarded scar formation, we noted 3 luxations of the meniscus, 2 involving the medial meniscus and 1 the lateral meniscus. In 2 cases we had to change the meniscus (once under general anaesthesia) and in 1 cases had to reoperate to install a total prosthesis. The Oxford single compartment knee prosthesis is an important implant which has its place between osteotomy and a total prosthesis, when used according to rigorous technique. There is nevertheless the risk of meniscal luxation with this type of prosthesis.

Aged↗