[Evaluation of disinifecting of 5% sodium hypochlorite solution diluted to 2:100 along with the use of disposable covers on HBV contaminated dental office surfaces and equipments]

The efficiency of disinfecting materials and procedures in removal of contamination from dental surfaces and equipments is essential. In authors' previous study, daily use of 2:100 dilution of 5% sodium hypochlorite in water and disposable covers were recommended since HBV contamination was found on semi-critical parts of the operative dentistry department. The aim of this study was to evaluate the HBV contamination following application of the recommended procedures. The study was conducted in two parts. In the first cross-sectional part, samples were collected from 17 sites of dental surfaces. In the second interventional part samples were collected from 10 sites of 9 dental and 3 sites of 2 light cure units, before and after disinfection with 5% sodium hypochlorite solution diluted to 2:100. Sterile cotton swabs moistened with sterile BSAS [Bovcine Serum Albumin in Sodium Chloride] solution were used for sampling. Samples were tested by PCR technique in Pasteur Institute, Iran. None of the samples collected in the first part of the study showed contamination. In the second part of the study, from 96 samples taken from various parts of dental and light cure units, before and after disinfecting, there was only on HBV contaminated site before disinfection which showed not contamination after disinfection. Based on the results of this study, disinfecting procedure with 5% sodium hypochlorite solution diluted to 2:100 along with using disposable covers is effective in preventing HB contamination

[Evaluation the immunogenesity structure of HIV recombinant protein gp41-p24]

HIV recombinant proteins can be used as immunogen and inducer of immune system. The gag and env proteins are among the most important ones that are located on internal and surface sections, respectively. In this study, we considered the immunogenisity structure of HIV recombinant protein gp41-p24, which has not yet been studied in detail before. In the present study, the HIV recombinant protein gp41-p24 was prepared by cloning methods and kept as unfolded. Using the dilution procedure, unfolded protein was changed to refolded state. The molecular weight and concentration of protein [refolded and unfolded] was measured by electrophoresis and spectrophotometer methods. The measurement of refolded protein can be estimated by native gel and circular dichroism method [CD] based on secondary structure of the protein. Immunological activity and immunogenic structure of these two proteins, based on protein type and optical density was recorded by ELISA and western blot methods. Our results showed that molecular weight of each protein was 32 KD and also they were pure. The refolded protein was observed by native gel method. In the above protein compared with the unfolded one, increased content of helix and beta strand structures and decreased random form was shown. Immune reaction with the antibodies in the serum of HIV positive control patients was observed in the standard and refolded proteins. There was no significant difference based on the protein type. Our research indicated that the HIV recombinant protein gp41-p24, after refolding, has immunogenic activity and we suggest its application as an immunogen in immunization and stimulation of immune system