Short-Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea Pigs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anti-proliferative and cytotoxic activity of pentadactylin isolated from Leptodactylus labyrinthicus on melanoma cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Detecção de Curtobacterium flaccumfaciens pv. flaccumfaciens em sementes de feijoeiro produzidas em Santa Catarina

Foi avaliada a presença de Curtobacterium flaccumfaciens pv. flaccumfaciens em 37 amostras de sementes de feijoeiro, dos grupos preto e carioca, produzidas em municípios do Estado de Santa Catarina, nas safras 2004/2005 e 2005/2006. Para a detecção, as sementes foram maceradas e alíquotas de sua suspensão foram transferidas para o meio de cultura semi-seletivo MSCFF. A identidade dos isolados obtidos foi comprovada por meio da observação da morfologia celular, coloração diferencial de Gram, tolerância a NaCl a 7% e patogenicidade em cultivares de feijoeiro suscetíveis. Detectou-se a presença de Curtobacterium flaccumfaciens pv. flaccumfaciens em 23 amostras (62,2%), indicando a importância das sementes como fonte de inoculo inicial.

Cytotoxic effects of cleansing solutions recommended for chemical lavage of pulp exposures

Purpose: To evaluate the in vitro cytotoxic effects of three cleansing solutions used for chemical lavage of pulp exposures. Materials and Methods: the immortalized odontoblast cell line (MDPC-23) was plated (30,000 cells/cm(2)) and incubated for 72 hrs in 24-well dishes. After counting the cell number under inverted light microscopy, 20 mul of the experimental and control solutions were added to 980 mul of fresh culture medium. Then, hydrogen peroxide (3%, H2O2), sodium hypochlorite (6%, NaOCl) or calcium hydroxide-saline solution (5g of Ca(OH)(2) in 10 mi of sterile distilled water) were added to wells for experimental Groups 1, 2 and 3, respectively. The positive and negative control groups received Syntac Sprint bonding agent (SS) and phosphate buffered saline (PBS), respectively. Following incubation for 120 min the cell number was counted again, the cell morphology was evaluated by scanning electron microscopy (SEM) and the cell metabolism was determined by the methyltetrazolium (MTT) assay. The scores obtained from cell counting and MTT assay were analyzed with an ANOVA followed by Fisher's PLSD tests. Results: H2O2 NaOCl solutions, and SS bonding agent were more cytotoxic than Ca(OH)2 or PBS. In the groups with H2O2 Or SS, only a few cells remained attached to the bottom of wells. The difference between these two groups was not statistically significant. H2O2, NaOCl and SS depressed the mitochondrial enzyme response by 97.7%, 97.3%, and 95.0%, respectively. on the other hand, Ca(OH)2 depressed the metabolic activity of cells by only 5%. While H2O2, NaOCl and SS caused extreme changes on the cell morphology, neither Ca(OH)2 nor PBS promoted dramatic changes in the cell morphology.

Response of rat bone marrow cells to commercially pure titanium submitted to different surface treatments

Objectives. Alterations in the commercially pure titanium (cpTi) surface may be undertaken to improve its biological properties. The aim of this study is to investigate the biocompatibility of cpTi submitted to different surface treatments.Methods. The cpTi surfaces were prepared so that machined and blasted surfaces, either acid etched or not, were compared using rat bone marrow cells cultured to differentiated into osteoblast. For attachment evaluation, cells were cultured for 4 and 24 h. Cell morphology was evaluated after 3 days. After 7, 14, and 21 days cell proliferation was evaluated. Total protein content and alkaline phosphatase (ALP) activity were evaluated after 14 and 21 days. For bone-like nodule formation, cells were cultured for 21 days. Data were compared by analysis of variance.Results. Cell attachment, cell morphology, cell proliferation, and ALP activity were not affected by surface treatments. Total. protein content was reduced by blasted and acid etched surface. Bone-Like nodule formation was significantly reduced by blasted, acid etched, and a combination of both blasted and acid etched surfaces.Conclusions. Based on these results, it can be suggested that cpTi surfaces that were submitted only to machining treatment favor the final event of osteoblastic differentiation of the rat bone marrow cells, evidenced by increased bone-Like nodule formation. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Root surface conditioning with nicotine or cotinine reduces viability and density of fibroblasts in vitro

The purpose of study was to evaluate fibroblast attachment and cellular morphology on root surfaces chemically conditioned with nicotine or cotinine. A secondary objective was to determine if mechanical scaling and root planning of these chemically conditioned surfaces would alter cellular attachment. Root surface dentin specimens were prepared from uniradicular teeth of non-smoking patients. Specimens were randomly assigned to two experimental groups: no treatment (chemical conditioning only) and scaling and root planning after conditioning (SRPC). The concentrations of the tested substances were in the range of 0-1 mg/mL (nicotine) and 0-1 ?g/mL (cotinine). After a 24-h conditioning period, dentin slices were incubated with continuous lineage of fibroblastic cells from rat (McCoy cells) for another 24 h. Specimens were prepared for SEM analysis and microphotographs. The statistical analysis of the data indicated significant alteration of cellular morphology on fibroblasts that were grown on root surface exposed to nicotine concentrations greater than 1 ? g/mL. This effect of nicotine was not reduced by SRPC. on the other hand, in the SRPC group cellular density was greater. For cotinine-conditioned specimens, the greater concentrations also led to alteration on morphology, and these alterations were observed in the SRPC group as well. Cotinine did not induce significant changes on cellular density. The results indicated that fibroblasts are negatively influenced by nicotine present on the dentin substrate and also that scaling may reduce these effects. Cotinine treatment on root surfaces may alter cell morphology and density but these effects were less severe than that promoted by nicotine, and were not affected by scaling.

In vitro biocompatibility of poly(vinylidene fluoride-trifluoroethylene)/barium titanate composite using cultures of human periodontal ligament fibroblasts and keratinocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cellular and tissue effects induced by photogemA (R) and red LED in photodynamic therapy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effectiveness of Microwave Sterilization on Three Hard Chairside Reline Resins

Purpose: The aim of this study was to evaluate the effectiveness of microwave irradiation sterilization on hard chairside reline resins. Materials and Methods: Specimens of three reline resins (Kooliner, Tokuso Rebase, and Ufi Gel Hard) were fabricated and subjected to ethylene oxide sterilization. The specimens were then individually inoculated (107 cfu/mL) with Tryptic Soy Broth media containing one of the tested microorganisms (C albicans, S aureus, B subtilis, and P aeruginosa). After 48 hours at 37°C, the samples were vortexed for 1 minute and allowed to stand for 9 minutes, followed by a short vortex to resuspend any organisms present. After inoculation, 40 specimens of each material were immersed in 200 mL of water and subjected to microwave irradiation at 650 W for 6 minutes. Forty non-irradiated specimens were used as positive controls. Replicate specimens (25 μL) of suspension were plated at dilutions of 10-3 to 10-6 on plates of selective media appropriate for each organism. All plates were incubated at 37°C for 48 hours. After incubation, colonies were counted, and the data were statistically analyzed by the Kruskal-Wallis test. Twelve specimens of each material were prepared for SEM. Results: All immersed specimens showed consistent sterilization of all the individual organisms after microwave irradiation. SEM examination indicated an alteration in cell morphology after microwave irradiation. Conclusion: Microwave sterilization for 6 minutes at 650 W proved to be effective for the sterilization of hard chairside reline resins.

Cytotoxic effects of different concentrations of chlorhexidine

Purpose: To evaluate the cytotoxic effects of different concentrations of Chlorhexidine (Chx) to the odontoblast cell line MDPC-23. Methods: The odontoblast-like cells were seeded (30,000 cells/cm 2) in 60 wells of 24-well dishes and then incubated in contact with the following experimental and control solutions: Group 1: 0.0024% Chx; Group 2: 0.004% Chx; Group 3: 0.02% Chx; Group 4: Phosphate buffer saline solution (PBS, negative control); and Group 5: 0.06% H 2O 2 (positive control). Cell metabolic activity was measured by MTT assay and the cell morphology was analyzed by SEM. Results: The cytotoxic effects of Chx are dose-dependent. The reduction in the cell metabolism for Groups 1, 2, and 3 was 24.8%, 29.9% and 70.8%, respectively. No statistical difference was observed between the Groups 1 and 2 in which no significant cell morphology changes occurred. Consequently, it was concluded that 0.02% Chx solution presents high cytotoxicity to the odontoblast-like cells MDPC-23. On theother hand, 0.0024% and 0.004% Chx causes slight cytopathic effects to the cultured cells.

Effect of different exposure times on microwave irradiation on the disinfection of a hard chairside reline resin

Purpose: This study evaluated the effectiveness of different exposure times of microwave irradiation on the disinfection of a hard chairside reline resin. Materials and Methods: Sterile specimens were individually inoculated with one of the tested microorganisms (Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Bacillus subtilis) and incubated for 24 hours at 37°C. For each microorganism, 10 specimens were not microwaved (control), and 50 specimens were microwaved. Control specimens were individually immersed in sterile saline, and replicate aliquots of serial dilutions were plated on selective media appropriate for each organism. Irradiated specimens were immersed in water and microwaved at 650 W for 1, 2, 3, 4, or 5 minutes before serial dilutions and platings. After 48 hours of incubation, colonies on plates were counted. Irradiated specimens were also incubated for 7 days. Some specimens were prepared for scanning electron microscopic (SEM) analysis. Results: Specimens irradiated for 3, 4, and 5 minutes showed sterilization. After 2 minutes of irradiation, specimens inoculated with C. albicans were sterilized, whereas those inoculated with bacteria were disinfected. One minute of irradiation resulted in growth of all microorganisms. SEM examination indicated alteration in cell morphology of sterilized specimens. The effectiveness of microwave irradiation was improved as the exposure time increased. Conclusion: This study suggests that 3 minutes of microwave irradiation can be used for acrylic resin sterilization, thus preventing cross-contamination. © 2008 by The American College of Prosthodontists.

Indirect cytotoxicity of a 35% hydrogen peroxide bleaching gel on cultured odontoblast-like cells

The aim of this study was to evaluate the trans-enamel and trans-dentinal effects of a 35% hydrogen peroxide (H2O2) bleaching gel on odontoblast-like cells. Enamel/dentin discs obtained from bovine incisors were mounted in artificial pulp chambers (APCs). Three groups were formed: G1- 35% H2O2; G2- 35% H2O2 + halogen light application; G3- control. The treatments were repeated 5 times and the APCs were incubated for 12 h. Then, the extract was collected and applied for 24 h on the cells. Cell metabolism, total protein dosage and cell morphology were evaluated. Cell metabolism decreased by 62.09% and 61.83% in G1 and G2, respectively. The depression of cell metabolism was statistically significant when G1 and G2 were compared to G3. Total protein dosage decreased by 93.13% and 91.80% in G1 and G2, respectively. The cells in G1 and G2 exhibited significant morphological alterations after contact with the extracts. Regardless of halogen light application, the extracts caused significantly more intense cytopathic effects compared to the control group. After 5 consecutive applications of a 35% H2O2 bleaching agent, either catalyzed or not by halogen light, products of gel degradation were capable to diffuse through enamel and dentin causing toxic effects to the cells.

Cytotoxic effects of white-MTA and MTA-Bio cements on odontoblast-like cells (MDPC-23)

This study evaluated the cytotoxic effects of 2 mineral trioxide aggregate (MTA) cements - White-MTA-Angelus and a new formulation, MTA-Bio - on odontoblast-like cell (MDPC-23) cultures. Twenty-four disc-shaped (2 mm diameter x 2 mm thick) specimens were fabricated from each material and immersed individually in wells containing 1 mL of DMEM culture medium for either 24 h or 7 days to obtain extracts, giving rise to 4 groups of 12 specimens each: G1 - White-MTA/24 h; G2 - White-MTA/7 days; G3 - MTA-Bio/24 h; and G4 - MTA-Bio/7 days. Plain culture medium (DMEM) was used as a negative control (G5). Cells at 30,000 cells/cm 2 concentration were seeded in the wells of 24-well plates and incubated in a humidified incubator with 5% CO 2 and 95% air at 37°C for 72 h. After this period, the culture medium of each well was replaced by 1 mL of extract (or plain DMEM in the control group) and the cells were incubated for additional 2 h. Cell metabolism was evaluated by the MTT assay and the data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Cell morphology and the surface of representative MTA specimens of each group were examined by scanning electron microscopy. There was no statistically significant difference (p>0.05) between G1 and G2 or between G3 and G4. No significant difference (p>0.05) was found between the experimental and control groups either. Similar cell organization and morphology were observed in all groups, regardless of the storage periods. However, the number of cells observed in the experimental groups decreased compared to the control group. MTA-Bio presented irregular surface with more porosities than White-MTA. In conclusion, White-MTA and MTA-Bio presented low cytotoxic effects on odontoblast-like cell (MDPC-23) cultures.

In vitro effect of low-level laser therapy on typical oral microbial biofilms

The aim of this study was to evaluate the effect of specific parameters of low-level laser therapy (LLLT) on biofilms formed by Streptococcus mutans, Candida albicans or an association of both species. Single and dual-species biofilms - SSB and DSB - were exposed to laser doses of 5, 10 or 20 J/cm 2 from a near infrared InGaAsP diode laser prototype (LASERTable; 780 ± 3 nm, 0.04 W). After irradiation, the analysis of biobilm viability (MTT assay), biofilm growth (cfu/mL) and cell morphology (SEM) showed that LLLT reduced cell viability as well as the growth of biofilms. The response of S. mutans (SSB) to irradiation was similar for all laser doses and the biofilm growth was dose dependent. However, when associated with C. albicans (DSB), S. mutans was resistant to LLLT. For C. albicans, the association with S. mutans (DSB) caused a significant decrease in biofilm growth in a dose-dependent fashion. The morphology of the microorganisms in the SSB was not altered by LLLT, while the association of microbial species (DSB) promoted a reduction in the formation of C. albicans hyphae. LLLT had an inhibitory effect on the microorganisms, and this capacity can be altered according to the interactions between different microbial species.

Efficacy and cytotoxicity of a bleaching gel after short application times on dental enamel

Objectives: This study aimed to evaluate and correlate the efficacy and cytotoxicity of a 35 % hydrogen peroxide (HP) bleaching gel after different application times on dental enamel. Materials and methods: Enamel/dentin disks in artificial pulp chambers were placed in wells containing culture medium. The following groups were formed: G1, control (no bleaching); G2 and G3, three or one 15-min bleaching applications, respectively; and G4 and G5, three or one 5-min bleaching applications, respectively. Extracts (culture medium with bleaching gel components) were applied for 60 min on cultured odontoblast-like MDPC-23 cells. Cell metabolism (methyl tetrazolium assay) (Kruskal-Wallis/Mann-Whitney; α = 5 %) and cell morphology (scanning electron microscopy) were analyzed immediately after the bleaching procedures and the trans-enamel and trans-dentinal HP diffusion quantified (one-way analysis of variance/Tukey's test; α = 5 %). The alkaline phosphatase (ALP) activity was evaluated 24 h after the contact time of the extracts with the cells (Kruskal-Wallis/Mann-Whitney; α = 5 %). Tooth color was analyzed before and 24 h after bleaching using a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system (Kruskal-Wallis/Mann-Whitney; α = 0.05). Results: Significant difference (p < 0.05) in cell metabolism occurred only between G1 (control, 100 %) and G2 (60.6 %). A significant decrease (p < 0.05) in ALP activity was observed between G2, G3, and G4 in comparison with G1. Alterations on cell morphology were observed in all bleached groups. The highest values of HP diffusion and color alterations were observed for G2, with significant difference among all experimental groups (p < 0.05). G3 and G4 presented intermediate color change and HP diffusion values with no statistically significant differences between them (p > 0.05). The lowest amount of HP diffusion was observed in G5 (p < 0.05), which also exhibited no significant color alteration compared to the control group (p > 0.05). Conclusions: HP diffusion through dental tissues and its cytotoxic effects were proportional to the contact time of the bleaching gel with enamel. However, shorter bleaching times reduced bleaching efficacy. Clinical relevance: Shortening the in-office tooth bleaching time could be an alternative to minimize the cytotoxic effects of this clinical procedure to pulp tissue. However, the reduced time of bleaching agent application on enamel may not provide adequate esthetic outcome. © 2012 Springer-Verlag Berlin Heidelberg.