Microbiological evaluation of dental stone casts after immersion in sodium hypochlorite and peracetic acid

<p class="western" align="justify"><span style="color: #000000;"><span style="font-family: Arial, serif;"><strong>Objective</strong></span></span><span style="color: #000000;"><span style="font-family: Arial, serif;">: the purpose of this study was to evaluate the efficacy of disinfection of type III dental stone by immersion in 1% sodium hypochlorite and 0.25% peracetic acid at different </span></span><span style="font-family: Arial, serif;">periods of time (1, 5 and 10 min). </span><span style="color: #000000;"><span style="font-family: Arial, serif;"><strong>Material</strong></span></span><span style="color: #000000;"><span style="font-family: Arial, serif;"><strong>and</strong></span></span><span style="color: #000000;"><span style="font-family: Arial, serif;"><strong>Methods</strong></span></span><span style="color: #000000;"><span style="font-family: Arial, serif;">: s</span></span><span style="font-family: Arial, serif;">ilicon dies were previously infected with strains of </span><span style="font-family: Arial, serif;"><em>Bacillus subtilis</em></span><span style="font-family: Arial, serif;"> for 15 min. Then</span><span style="color: #000000;"><span style="font-family: Arial, serif;">, type III gypsum stone (Herodent, </span></span><span style="font-family: Arial, serif;">Vigodent COLTÈNE SA, Rio de Janeiro, Brazil</span><span style="color: #000000;"><span style="font-family: Arial, serif;">) was inserted </span></span><span style="font-family: Arial, serif;">into the cavities to obtain contaminated specimens. A sterile silicone die was used to obtain uncontaminated specimens. The specimens were separated into positive and negative control groups, and further divided into the following groups: blocks immersed in sterile physiologic solution for 1, 5 or 10 min; blocks immersed in 1% sodium hypochlorite for 1, 5 or 10 min; and blocks immersed in 0.25% peracetic acid for 1, 5 or 10 min. All the groups were double-plated and incubated at 37 ˚C for 24 h. </span><span style="color: #000000;"><span style="font-family: Arial, serif;"><strong>Results</strong></span></span><span style="color: #000000;"><span style="font-family: Arial, serif;">: t</span></span><span style="font-family: Arial, serif;">he results were expressed in colony forming units (CFU/ml) and the data were submitted to the Kruskal-Wallis test followed by Dunn’s test. The results showed that immersion in 1% sodium hypochlorite and 0.25% peracetic acid resulted in complete disinfection of the test specimens at all test periods (p &lt; 0.01), whereas immersion in saline did not provide effective disinfection. </span><span style="font-family: Arial, serif;"><strong>Conclusion</strong></span><span style="font-family: Arial, serif;">: i</span><span style="color: #000000;"><span style="font-family: Arial, serif;">t can be concluded that both 1% sodium hypochlorite and 0.25% peracetic acid provided effective disinfection in dental stone specimens immersed in the solutions described above, at different periods of time.</span></span></p><p class="western" align="justify"><span style="color: #000000;"><span style="font-family: Arial, serif;"><strong>Keywords</strong></span></span></p><p class="western" align="justify"><span style="color: #000000;"><span style="font-family: Arial, serif;">Disinfection; Peracetic acid; Sodium hypochlorite; Stone casts.</span></span></p>

Viscoelastic Properties of a Synthetic Meniscus Implant

Meniscal tears often lead to degenerative arthritis, attributed primarily to the changes in the magnitude and pattern of stress distribution in the knee. While meniscal replacement traditionally involves implantation of allografts, problems related to availability, size matching, and cost limit their use. In this regard, there are significant potential advantages to a bio-stable synthetic meniscus implant that combines long-term durability with a dependable biomechanical performance resembling that of the natural meniscus. The Nusurface ® medial Meniscus Implant is a poly-(carbonate-urethane) implant that recreates the functionality of the meniscus, as evidenced by compression tests to determine its pressure distribution capability [1] and finite element analyses [2] in its virgin state. However, the overall success of such an implant is dependent on its long-term functional properties, and biomechanical testing of the NUsurface ® device has not yet examined the effect of varying and dynamic testing conditions. In particular, the pre-test soaking in physiologic solution and the loading rate can have non-trivial influences on the properties of the device. Therefore the aims of this study were to characterize the strain-rate response, as well as the viscoelastic properties of the implant as measured by creep, stress relaxation, and hysteresis after simulated use.

Lipid peroxidation in rats treated with vincristine sulphate and nandrolone decanoate

Brain and serum lipid peroxidation was studied in rats treated with vincristine sulphate and different doses of nandrolone decanoate. Thirty rats were distributed into six groups (n=5). The treatments were applied once a week for two weeks. Sample collection was performed in the third week. Treatments during the first week were: G1 (control) - physiologic solution, G2 - vincristine sulphate (4mg/m²), G3 - physiologic solution, G4 - physiologic solution, G5- vincristine sulphate (4mg/m²), and G6 - vincristine sulphate (4mg/m²). In the second week, they were: G1 (control) - physiologic solution, G2- physiologic solution, G3 - nandrolone decanoate (1.8mg/kg-1), G4 - nandrolone decanoate (10mg/kg-1), G5 - nandrolone decanoate (1.8mg/kg-1), and G6 - nandrolone decanoate (10mg/kg-1). Lipid peroxidation increased with the isolated use of vincristine and nandrolone decanoate, and with vincristine associated to the highest dose of the ester as well. These results suggest that vincristine sulphate and nandrolone decanoate increase free radical production. Therapeutic dose of nandrolone decanoate when associated with vincristine sulphate proved to be beneficial, as it was able to protect the organism from damaging processes involved in free radical production

Using of oxygenic infusion solutions in treatment of patients with bronchial asthma

Oxygen concentration before and after oxygenation and relaxation time were determined by the method of cathodic voltammetry in infusion solutions, such as physiologic solution — 0.9% NaCl, Ringer-Locc’s solution, glucose — 10%, poliglucin, haemodes, oxigenated by 5 athm. pressure.There were given the recommendations for practical usage of oxigenated infusical solutions.The most optimal solutions for the oxygenotherapy are physiologic solution and poliglucin. 12 patients with bronchial asthma were treated with these solutions successfully.

Near-Field Scanning Optical Images of Bacteria

ABSTRACTNear field scanning optical microscopy (NSOM) and spectroscopy techniques were used to study the shape and the cell membrane details in bacteria. We present transmission and topo-graphic images for the bacteriaPseudomonas aeruginosausing the Aurora NSOM from ThermoMicroscopes. TheP. aeruginosahas been widely studied due to its clinical importance in many infectious diseases. The samples were stained by the Gram method and we measured the absorption of laser light at 488 nm by the dye (Safranin) fixed at the bacteria membrane. To obtain good images we had to improve the sample preparation in order to obtain isolated bacteria at the microscope slab. This was achieved using individual colonies, from a dry growth procedure, diluted in physiologic solution. Comparison of the topographic and transmission images give information on the shape and details of the absorption of the laser light by the cell membrane. The results show patterns that depend on the thickness and shape of the membrane, thus revealing details of the cell membrane with nanometer resolution. These results could be an important tool for instance in studies of the effects of antibiotics on the cell membrane.