Sodium Bicarbonate Jet Reduces Contamination of Dental Implants In Vitro Without Causing Visible Surface Changes.

PURPOSE: The increasing use of dental implants in oral rehabilitation has contributed to the increase of cases of peri-implantitis, a complex clinical condition that persists without an ideal treatment protocol. Therefore, this study aimed to verify the decontaminating action of the sodium bicarbonate jet in vitro, using different protocols, and the presence of visible changes on the surface of dental implants. MATERIALS AND METHODS: Sixteen titanium implants (BioHE, Bioconnect) were used, divided into four groups (four implants per group): sterile implants (S)-negative control; implants contaminated with oral biofilm (C)-positive control; and implants contaminated with oral biofilm and decontaminated with a sodium bicarbonate jet for 30 seconds (J30) or 60 seconds (J60). The implants of groups C, J30, and J60 were contaminated in vitro with oral biofilm, then groups J30 and J60 received the respective decontamination treatments. Microbiologic analysis was performed by counting the colony-forming units (CFUs), and a qualitative descriptive analysis of the implant surface was performed after microbiologic analysis using scanning electron microscopy (SEM). Statistical analysis included one-way analysis of variance (ANOVA) and Tukey tests and the independent t test, with a .05 significance level. RESULTS: There was a significant reduction (P < .01) in the number of CFUs in groups J30 (3.63 × 106 ± 0.32) and J60 (2.74 × 106 ± 0.21) compared with group C (5.05 × 106 ± 0.43). Both decontaminated groups were statistically different from group S, which did not show bacterial growth (P < .01). When groups J30 and J60 were compared, there was also a significant difference between them (P < .01), and the group J60 showed greater decontaminating potential. The descriptive qualitative analysis did not show any visible changes on the surface of the implants. CONCLUSION: The sodium bicarbonate jet was effective in decontaminating titanium implants in vitro, causing no visible damage to the implant surface.

Synthesis and anti-Mycobacterium tuberculosis activity of imide-ß-carboline and carbomethoxy-ß-carboline derivatives.

A series of methyl ß-carboline carboxylates (2a-g) and of imide-ß-carboline derivatives containing the phthalimide (4a-g), maleimide (5b, g) and succinimide (6b, e, g) moiety were synthesized, and evaluated for their activity against Mycobacterium tuberculosis H37Rv. The most active ß-carboline derivatives against the reference strain were assayed for their cytotoxicity and the activity against resistant M. tuberculosis clinical isolates. Farther, structure-activity relationship (SAR) studies were carried out using the three and four-dimensional approaches for starting to understand the way of ß-carboline activity in M. tuberculosis. All 19 ß-carboline derivatives were assayed, firstly, by determining the minimum inhibitory concentration (MIC) using resazurin microtiter assay plate (REMA) in M. tuberculosis H37Rv. Then, five derivatives (2c, 4a, 4e, 4g, 6g), which showed MIC ≤ 125 µg/mL, were assayed in nine resistant M. tuberculosis clinical isolates (five MDR, three isoniazid monoresistant and one isoniazid plus streptomycin resistant). The MIC values against the resistant clinical isolates ranged from 31.25 to >250 µg/mL. All five derivatives were non-cytotoxic to the VERO cell line, determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, at the tested concentration (selectivity index ranged from <1.74 to 14.4). Our study demonstrated that (2c) and (6g) derivatives had better anti-M. tuberculosis activity, especially against resistant clinical isolates, what makes them scaffold candidates for further investigations about their anti-tuberculosis activity. The SAR study conducted with the 19 ß-carboline derivatives showed the importance of steric effects for the synthesized ß-carbolines against M tuberculosis, and these models can be used for future proposition of new derivatives, increasing the chances of obtaining potentially anti-tuberculosis compounds.

Anti-Mycobacterium tuberculosis activity of essential oil and 6,7-dehydroroyleanone isolated from leaves of Tetradenia riparia (Hochst.) Codd (Lamiaceae).

BACKGROUND: The global resurgence of tuberculosis (TB) and the development of drug resistance, as multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis isolates, are a threat to TB control and have created a need for new and more effective anti-TB drugs. AIM: The current study evaluated the in vitro cytotoxicity and activity of Tetradenia riparia essential oil (TrEO) and 6,7-dehydroroyleanone pure compound against M. tuberculosis H37Rv and susceptible and resistant clinical isolates. METHODS: The in vitro activities of TrEO and 6,7-dehydroroyleanone were determined by Resazurin Microtiter Assay Plate (REMA). The cytotoxicity was evaluated in murine peritoneal macrophages by Alamar Blue assay. The cytotoxic effects were expressed as median concentration cytotoxicity (CC50) and the selectivity index (SI) was calculated. RESULTS: TrEO and 6,7-dehydroroyleanone showed activity against M. tuberculosis H37Rv with minimum inhibitory concentration (MIC) 62.5 µg/ml and 31.2 µg/ml, respectively. Both of them exhibited activities against resistant and susceptible M. tuberculosis clinical isolates with MIC values between 31.2 and 62.5 µg/ml. Cytotoxicity assays showed SI 1.9 and 7.9 for TrEO and 6,7-dehydroroyleanone, respectively. CONCLUSION: These results revealed that TrEO isolated from leaves of T. riparia and the pure compound 6,7-dehydroroyleanone display good activity against M. tuberculosis clinical isolates, including MDR isolates, with low cytotoxicity to murine macrophages. The 6,7-dehydroroyleanone compound is a potential candidate for anti-TB drug.