The effect of different combinations of fixatives and decalcifying agents on rat and rabbit hard tissues, a guide for histologic processing.

BACKGROUND AND PURPOSE: In order to acquire the best method that can simultaneously maximize tissue morphology and staining quality, we compared the effect of different fixative and decalcifying solutions on the quality of rabbit and rat bone histology. METHOD: Fifty-four rat hemimaxillae and 54 rabbit quarter-parietal bones were allocated into 3 fixation groups (formalin, 10 %sodium-phosphate-buffered-formalin and 10 %calcium-phosphate-buffered-formalin). Each fixative was divided into 6 groups and decalcified with 5 % and 10 % nitric acid (NA), 5 % and 10 % formic acid (FA), Gooding-Stewart liquid (GSL) and EDTA. Slide quality was evaluated on hematoxylin/eosin slides by 3 observers and mean-scores for total-cell-characteristics (TCC) and total-tissue-characteristics (TTC) were statistically analyzed. RESULT: Significant differences in decalcification-time were observed in different combinations of decalcifiers and fixatives in both animals. In rats, TCC was better preserved when using 10 %NA/calcium-phosphate-buffered-formalin compared to 10 %NA/sodium-phosphate-buffered-formalin (P = 0.03). GSL/sodium-phosphate-buffered-formalin performed better than both other fixatives (P < 0.001). TCC differed among the decalcifiers in each of the fixatives. In rabbits, there were differences in TCC among the decalcifiers when formalin (P = 0.001) and sodium-phosphate-buffered-formalin (P = 0.01) were used. TTC only showed significant difference when 10 %FA was used in rats (P = 0.044), with formalin performing better than sodium-phosphate-buffered-formalin (P = 0.01). CONCLUSION: Based on our results, if time is an issue, 10 %NA/calcium-phosphate-buffered-formalin could provide good cellular quality and if time is not a consideration, FA (5 % or 10 %) with sodium-phosphate-buffered-formalin followed by EDTA with formalin, would have the best performance. In rabbits, GSL provides the fastest results, regardless of the fixative and FA/sodium-phosphate-buffered-formalin gives the best cellular quality.

Evaluation of Antibacterial Effect of Propolis and its Application in Mouthwash Production.

OBJECTIVES: Our purpose was to determine the antibacterial properties of propolis and to evaluate its use as an antibacterial mouthwash with minimal complications. MATERIALS AND METHODS: In this experimental laboratory study, an alcoholic propolis extract was prepared. The minimum inhibitory concentration (MIC) was calculated for four bacterial species including Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Lactobacillus acidophilus (L. acidophilus), and Enterococcus faecalis (E. faecalis) using agar dilution. According to the MIC, a propolis antibacterial mouthwash was produced and compared to water, chlorhexidine (CHX), and Listerine using laboratory rats for clinical examination. Salivary specimens of rats were collected at 12 hours, 1 week, and 2 weeks after using the mouthwash and examined by real-time polymerase chain reaction (RT-PCR). Data were analyzed using one-way analysis of variance (ANOVA) and repeated measures ANOVA (α=0.05). RESULTS: The results of agar dilution by the number of colony-forming units showed the lowest MIC for S. aureus and the highest for L. acidophilus. Our RT-PCR findings indicated that water alone had no effect on the level of oral bacteria. Propolis mouthwash showed a significant difference with CHX and Listerine (P<0.05) in terms of the number of S. mutans, E. faecalis, and L. acidophilus colonies, while CHX and Listerine were less efficient. There was no significant difference between CHX and propolis (P=0.110) regarding S. aureus colonies, but Listerine had a lower efficacy than either (P<0.05). CONCLUSION: According to the results, propolis mouthwash was more efficient against the studied oral bacteria compared to CHX and Listerine.

Association of Stromal Factors With the Histologic Risk Assessment Model in Oral Squamous Cell Carcinoma.

The aim of the present study was to evaluate angiogenesis, lymphangiogenesis, and mast cell density in association with the histologic risk assessment (HRA) model in oral squamous cell carcinoma. One hundred oral squamous cell carcinomas were graded according to the HRA system and immunostained with antibodies against D2-40, CD34, and CD105 to determine lymphvessel density (LVD) and microvessel density (MVD). Mast cells were detected by toluidine blue and counted in all samples. Assessments were made between the evaluated factors and the histologic variables of HRA. Kruskal-Wallis and Mann-Whitney U test were used for statistical analysis and P<0.05 was considered significant. There were 32, 26, and 42 cases of low, intermediate, and high-grade neoplasms, respectively. Only LVD (P=0.05) and CD34MVD (P=0.03) showed significant associations with lymphocytic infiltration and were both higher in score 0 cases compared with score 3 tumors (P=0.05 and <0.001, respectively). None of the other variables showed significant relationships with the HRA risk scores or subcategories (P>0.05). According to our findings, it appears that the role of lymphangiogenesis and angiogenesis is limited in the HRA system. The significant relationship of lymphocytic infiltration with LVD and CD34MVD, but not CD105MVD, might indicate that "inflammatory lymphangiogenesis/angiogenesis" may differ from that induced by noninflamed neoplastic tissues. It also seems that the vasculature in inflamed tumor tissues is not entirely newly formed.