6 years follow-up of hip revision surgery.

Revision total hip arthroplasty often presents surgeons with difficult bone loss problems. The purpose of this study was to evaluate the results of hip revision surgery according to bone stock We evaluated, in a retrospective study, 148 hip revision surgeries during 2004 to 2010. The Harris Hip Score (HHS), the acetabular cementation, the AAOS classification, the SOFCOT 99 bone loss grading and Barrack classification were used for clinical and radiological assessment. It can be observed significant improvement of HHS from a mean value of 45 preoperatively to 77.2 points postoperatively. Grade B acetabular cementation was observed in a significantly higher rate for situations that needed acetabular allograft reconstruction and where it cannot be performed because of allografts lack. Barrack grades C and D cementation were associated with 70% of SOFCOT 99 stage III and IV cases and only 5% of SOFCOT 99 stage 0-II cases.Using bone graft seems to be a reliable solution for restoring bone stock and stabilizing the cup in revision total hip arthroplasty with type II-IV acetabular defect according to the AAOS classification. Because SOFCOT 99 stages III-IV are often associated with poor cementation we prefer using uncemented distally fixed with screws revision stems for these cases.

Reaction of guanyl radicals in plasmid DNA with biological reductants: chemical repair of DNA damage produced by the direct effect of ionizing radiation.

PURPOSE: It has been previously argued that the use of the one-electron oxidants (SCN)2(*-) and Br2(*-) with plasmid DNA leads to the formation of DNA guanyl radicals. These guanyl radical species are intermediates in the DNA damage produced by processes such as photo-ionization and ionizing irradiation. The present paper evaluates the use of thallium(II) ions (Tl(II)OH(+)) as the one-electron oxidant, and also determines rate constants for the reduction (repair) of guanyl radicals in plasmid DNA by a variety of reducing agents including the biologically important compounds ascorbate and glutathione. MATERIALS AND METHODS: Aqueous solutions of plasmid DNA containing 10(-3) mol dm(-3) thiocyanate or thallous ions and a reducing agent (azide, nitrite, ferrocyanide, hexachloroiridate(III), iodide, ascorbate, glutathione, glutathione disulphide, methionine, tyrosine, 5-hydroxyindole-3-acetic acid, 10(-7)-10(-4) mol dm(-3)) were irradiated with 137Cs gamma-rays (662 keV). After irradiation, the plasmid was incubated with the E. coli base excision repair endonuclease formamidopyrimidine-DNA N-glycosylase (FPG). Strand break yields after incubation were quantified by means of agarose gel electrophoresis. RESULTS: High yields of FPG-sensitive sites produced by the oxidants (SCN)2(*-) and Tl(II)OH(+) were strongly attenuated by the presence of the reducing agents. CONCLUSIONS: From the results, it is possible to arrive at estimates of the rate constants for the reduction of the DNA guanyl radical by the reducing agents. Values lie in the range 10(4)-10(7) dm(3) mol(-1) s(-1). Using the values for ascorbate and glutathione, it is possible to estimate an upper limit on the order of milliseconds for the lifetime of DNA guanyl radicals under cellular conditions. The implication is that there may well be a significant chemical repair of DNA base damage by the direct effect of ionizing radiation.

Comparison of chromatographic methods for the analysis of glycerol esters.

Column, thin-layer and gel chromatography have been compared as methods for the analysis of glycerol esters. It was found that gel chromatography gave much easier and faster analyses of monoglyceride emulsifiers, while at the same time providing a satisfactory distribution of fractions and giving an accuracy of determination corresponding to that of the standard method for their analysis.