scholarly journals Differences of Cytotoxicity of Orthodontic Bands Assessed by Survival Tests inSaccharomyces cerevisiae

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Tatiana Siqueira Gonçalves ◽  
Luciane Macedo de Menezes ◽  
Luciele Gonzaga Ribeiro ◽  
Catieli Gobetti Lindholz ◽  
Renata Medina-Silva
Keyword(s):  
Artificial Saliva ◽  
Survival Rates ◽  
Negative Control ◽  
Yeast Cells ◽  
Orthodontic Appliances ◽  
Slight Reduction ◽  
Yeast Viability ◽  
Direct Exposure ◽  
Indirect Exposure ◽  
Laser Soldering

The aim of this study was to evaluate the cytotoxicity induced by orthodontic bands through survival tests onSaccharomyces cerevisiae,a microorganism that presents several genetic and biochemical characteristics similar to human cells. Three groups of bands were evaluated: silver soldered (SSB), laser soldered (LSB), and bands without any solder (WSB). Yeast cells were directly exposed to the bands and indirectly, when a previous elution of the metals in artificial saliva was performed. The negative control was composed of yeast cells or artificial saliva not exposed to any kind of metal. In the direct exposure experiments, all tested groups of bands induced a slight reduction in yeast viability compared to the control. This effect was more intense for the SSB, although not statistically significant. For the indirect exposure experiments, the SSB induced a statistically significant decrease in cell viability compared to the LSB. There were no significant differences between the survival rates of the negative control and the LSB group in both direct and saliva tests. SSBs were cytotoxic, whilst LSBs were not, confirming that laser soldering may be a more biocompatible alternative for use in connecting wires to orthodontic appliances.

scholarly journals Evaluation of ionic degradation and slot corrosion of metallic brackets by the action of different dentifrices

2013 ◽  
Vol 18 (1) ◽  
pp. 86-93
Author(s):  
Gustavo Antônio Martins Brandão ◽  
Rafael Menezes Simas ◽  
Leandro Moreira de Almeida ◽  
Juliana Melo da Silva ◽  
Marcelo de Castro Meneghim ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Artificial Saliva ◽  
Positive Control ◽  
Negative Control ◽  
Sem Analysis ◽  
Wilcoxon Test ◽  
Surface Polishing ◽  
Aluminium Ion ◽  
Negative Controls

OBJECTIVE: To evaluate the in vitro ionic degradation and slot base corrosion of metallic brackets subjected to brushing with dentifrices, through analysis of chemical composition by Energy Dispersive Spectroscopy (EDS) and qualitative analysis by Scanning Electron Microscopy (SEM). METHODS: Thirty eight brackets were selected and randomly divided into four experimental groups (n = 7). Two groups (n = 5) worked as positive and negative controls. Simulated orthodontic braces were assembled using 0.019 x 0.025-in stainless steel wires and elastomeric rings. The groups were divided according to surface treatment: G1 (Máxima Proteção Anticáries®); G2 (Total 12®); G3 (Sensitive®); G4 (Branqueador®); Positive control (artificial saliva) and Negative control (no treatment). Twenty eight brushing cycles were performed and evaluations were made before (T0) and after (T1) experiment. RESULTS: The Wilcoxon test showed no difference in ionic concentrations of titanium (Ti), chromium (Cr), iron (Fe) and nickel (Ni) between groups. G2 presented significant reduction (p < 0.05) in the concentration of aluminium ion (Al). Groups G3 and G4 presented significant increase (p < 0.05) in the concentration of aluminium ion. The SEM analysis showed increased characteristics indicative of corrosion on groups G2, G3 and G4. CONCLUSION: The EDS analysis revealed that control groups and G1 did not suffer alterations on the chemical composition. G2 presented degradation in the amount of Al ion. G3 and G4 suffered increase in the concentration of Al. The immersion in artificial saliva and the dentifrice Máxima Proteção Anticáries® did not alter the surface polishing. The dentifrices Total 12®, Sensitive® and Branqueador® altered the surface polishing.

scholarly journals EFFECT OF NIGELLA SATIVA SEED EXTRACT ON THE VIABILITY OF CANDIDA GLABRATA

2019 ◽  
pp. 84-87
Author(s):  
FARAH DIBA ◽  
RATNA FARIDA ◽  
SRI REDJEKI
Keyword(s):  
Candida Glabrata ◽  
Nigella Sativa ◽  
Artificial Saliva ◽  
Positive Control ◽  
Negative Control ◽  
Seed Extract ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
Common Opportunistic Infection ◽  
Yeast Nitrogen Base Medium

Objective: Candidiasis is a common opportunistic infection of the oral cavity caused by a yeast-like fungus called Candida. Candida glabrata is thesecond most frequently isolated species from this condition, after Candida albicans. This study aimed to evaluate the effect of Nigella sativa (blackcumin), known to possess antifungal properties, on the viability of C. glabrata.Methods: C. glabrata was added to a 96-microwell plate that was coated with artificial saliva and exposed to various concentrations (6.25%, 12.5%,25%, and 50%) of N. sativa seed extract; amphotericin B (250 mg/mL) was used as the positive control and 200 μL of yeast nitrogen base medium asthe negative control. The viability percentage of C. glabrata was determined by MTT assay.Results: The results showed that the viability values of C. glabrata were lower after exposure to the N. sativa seed extract when compared with thenegative control.Conclusion: The viability of Candida glabrata was decreased with increasing concentrations of the extract.

Exposure to genocide and the risk of schizophrenia: a population-based study

2015 ◽  
Vol 46 (4) ◽  
pp. 855-863 ◽  
Author(s):  
S. Z. Levine ◽  
I. Levav ◽  
Y. Goldberg ◽  
I. Pugachova ◽  
Y. Becher ◽  
...  
Keyword(s):  
Cox Regression ◽  
Population Based ◽  
In Utero ◽  
Sensitivity Analyses ◽  
Critical Periods ◽  
Population Based Study ◽  
Regression Modelling ◽  
Direct Exposure ◽  
The Holocaust ◽  
Indirect Exposure

BackgroundNo evidence exists on the association between genocide and the incidence of schizophrenia. This study aims to identify critical periods of exposure to genocide on the risk of schizophrenia.MethodThis population-based study comprised of all subjects born in European nations where the Holocaust occurred from 1928 to 1945, who immigrated to Israel by 1965 and were indexed in the Population Register (N = 113 932). Subjects were followed for schizophrenia disorder in the National Psychiatric Case Registry from 1950 to 2014. The population was disaggregated to compare groups that immigrated before (indirect exposure: n = 8886, 7.8%) or after (direct exposure: n = 105 046, 92.2%) the Nazi or fascist era of persecutions began. The latter group was further disaggregated to examine likely initial prenatal or postnatal genocide exposures. Cox regression modelling was computed to compare the risk of schizophrenia between the groups, adjusting for confounders.ResultsThe likely direct group was at a statistically (p < 0.05) greater risk of schizophrenia (hazard ratio = 1.27, 95% confidence interval 1.06–1.51) than the indirect group. Also, the likely combined in utero and postnatal, and late postnatal (over age 2 years) exposure subgroups were statistically at greater risk of schizophrenia than the indirect group (p < 0.05). The likely in utero only and early postnatal (up to age 2 years) exposure subgroups compared with the indirect exposure group did not significantly differ. These results were replicated across three sensitivity analyses.ConclusionsThis study showed that genocide exposure elevated the risk of schizophrenia, and identified in utero and postnatal (combined) and late postnatal (age over 2 years) exposures as critical periods of risk.

Survival of Macrobrachium amazonicum embryos submitted to cooling

Zygote ◽  
2017 ◽  
Vol 25 (3) ◽  
pp. 288-295 ◽  
Author(s):  
Arthur Vinícius Lourenço Ferreira ◽  
Moisés Fernandes Martins ◽  
Míriam Luzia Nogueira Martins de Sousa ◽  
Aldeney Andrade Soares Filho ◽  
Célia Maria de Souza Sampaio
Keyword(s):  
Survival Rate ◽  
Storage Time ◽  
Survival Rates ◽  
Negative Control ◽  
Control Groups ◽  
Treatment Groups ◽  
Significant Difference ◽  
Macrobrachium Amazonicum ◽  
Cryoprotectant Solution ◽  
Positive Controls

SummaryCooling techniques have several applications for reproduction in aquaculture. However, few studies have sought to create protocols for cooling and cryopreservation of Macrobrachium amazonicum embryos. Thus, the objective of this work was to verify the survival of M. amazonicum embryos and the correlation between embryonic volume and mortality of M. amazonicum embryos after cooling. Embryo pools were collected from three females and divided into two treatment groups: dimethyl sulfoxide (DMSO) 3% and ethylene glycol (EG) 0.5%, both of them associated with 2 M sucrose. Positive and negative control groups consisted of seawater 10%. Aliquots of 10 µg of embryos were placed in Falcon® tubes containing a cryoprotectant solution and submitted directly to the test temperature of 2°C for 2 and 6 h of cooling. Further analysis of survival and embryonic volume were performed under a stereoscopic microscope. Data were subjected to analysis of variance (ANOVA), and means were compared using the Tukey test at 5%. The highest embryonic survival rate was observed after the shortest storage time for both the DMSO 3% and the 0.5% EG groups, with survival rates of 84.8 ± 3.9 and 79.7 ± 2.8%, respectively. There was a reduction in survival after 24 h, with the DMSO 3% group presenting a survival rate of 71.7 ± 6.6%, and the EG 0.5% group, 66 ± 6.9%. Survival showed a statistically significant difference when compared with the positive controls after 2 h and 24 h of cooling, with 99 ± 0.5% and 95.8 ± 1.5% survival rates, respectively. There was no significant statistical difference in the embryonic volume, but it was possible to observe a change in the appearance of the embryos, from a translucent coloration to an opaque white or brownish coloration, after 24 h in incubators. Thus, it can be concluded that survival is inversely proportional to storage time and that, although there was no change in the embryonic volume after cooling, a change in the appearance of embryos could be observed.

scholarly journals Evaluation of biochemical and serological methods to identify and clustering yeast cells of oral Candida species by CHROMagar test, SDS-PAGE and ELISA

2004 ◽  
Vol 64 (2) ◽  
pp. 317-326 ◽  
Author(s):  
J. A. de O. Rodrigues ◽  
J. F. Höfling ◽  
F. C. A. Tavares ◽  
K. M. R. Duarte ◽  
R. B. Gonçalves ◽  
...  
Keyword(s):  
Candida Species ◽  
Profile Analysis ◽  
Protein Profile ◽  
Negative Control ◽  
Yeast Cells ◽  
Sds Page ◽  
Differential Medium ◽  
Oral Yeasts ◽  
Species Specific ◽  
High Level

The purpose of this work was to evaluate biochemical and serological methods to characterize and identify Candida species from the oral cavity. The strains used were five Candida species previously identified: C. albicans, C. guilliermondii, C. parapsilosis, C. krusei, C. tropicalis, and Kluyveromyces marxianus, as a negative control. The analyses were conducted through the SDS-PAGE associated with statistical analysis using software, chromogenic medium, and CHROMagar Candida (CA), as a differential medium for the isolation and presumptive identification of clinically important yeasts and an enzyme-linked immunoabsorbent assay (ELISA), using antisera produced against antigens from two C. albicans strains. This method enabled the screening of the three Candida species: C. albicans, C. tropicalis, and C. Krusei, with 100% of specificity. The ELISA using purified immunoglobulin G showed a high level of cross-reaction against protein extracts of Candida species. The SDS-PAGE method allowed the clustering of species-specific isolates using the Simple Matching coefficient, S SM = 1.0. The protein profile analysis by SDS-PAGE increases what is known about the taxonomic relationships among oral yeasts. This methodology showed good reproducibility and allows collection of useful information for numerical analysis on information relevant to clinical application, and epidemiological and systematical studies.

Forming Tool Use Representations: A Neurophysiological Investigation into Tool Exposure

2011 ◽  
Vol 23 (10) ◽  
pp. 2920-2934 ◽  
Author(s):  
John Christopher Mizelle ◽  
Teresa Tang ◽  
Nikta Pirouz ◽  
Lewis A. Wheaton
Keyword(s):  
Learning Strategies ◽  
Tool Use ◽  
Motor Planning ◽  
Hemispheric Dominance ◽  
Neural Activation ◽  
The Novel ◽  
Beta Band ◽  
Related Information ◽  
Direct Exposure ◽  
Indirect Exposure

Prior work has identified a common left parietofrontal network for storage of tool-related information for various tasks. How these representations become established within this network on the basis of different modes of exposure is unclear. Here, healthy subjects engaged in physical practice (direct exposure) with familiar and unfamiliar tools. A separate group of subjects engaged in video-based observation (indirect exposure) of the same tools to understand how these learning strategies create representations. To assess neural mechanisms engaged for pantomime after different modes of exposure, a pantomime task was performed for both tools while recording neural activation with high-density EEG. Motor planning–related neural activation was evaluated using beta band (13–22 Hz) event-related desynchronization. Hemispheric dominance was assessed, and activation maps were generated to understand topography of activations. Comparison of conditions (effects of tool familiarity and tool exposure) was performed with standardized low-resolution brain electromagnetic tomography. Novel tool pantomime following direct exposure resulted in greater activations of bilateral parietofrontal regions. Activations following indirect training varied by tool familiarity; pantomime of the familiar tool showed greater activations in left parietofrontal areas, whereas the novel tool showed greater activations at right temporoparieto-occipital areas. These findings have relevance to the mechanisms for understanding motor-related behaviors involved in new tools that we have little or no experience with and can extend into advancing theories of tool use motor learning.

High Hydrostatic Pressure Come-Up Time and Yeast Viability

1998 ◽  
Vol 61 (12) ◽  
pp. 1657-1660 ◽  
Author(s):  
E. PALOU ◽  
A. LÓPEZ-MALO ◽  
G. V. BARBOSA-CÁNOVAS ◽  
J. WELTI-CHANES ◽  
P. M. DAVIDSON ◽  
...  
Keyword(s):  
Growth Phase ◽  
Growth Cycle ◽  
Stationary Growth Phase ◽  
Yeast Cells ◽  
Exponential Growth Phase ◽  
Stationary Growth ◽  
Survival Fraction ◽  
Zygosaccharomyces Bailii ◽  
Yeast Viability ◽  
Increased Sensitivity

The effects of the come-up time at selected pressures (50 to 689 MPa) on Saccharomyces cerevisiae and Zygosaccharomyces bailii viability were evaluated at 21°C. For Z. bailii the effects of the water activity (aw) of the suspension media and the stage of the growth cycle were also investigated. Pressure come-up times exerted an important effect on the yeast survival fraction, decreasing counts as pressure increased. An increased sensitivity to pressure treatments was observed with yeast cells from the exponential growth phase. Lethality increased as aw of the suspension media increased. For an aw of 0.98 and cells from the stationary growth phase, pressure treatments at less than 200 MPa had no effect on Z. bailii viability; however, no survivors (&lt;10 CFU/ml) were observed in treatments applied only for the time needed to reach pressures greater than 517 MPa. Yeast survivor curves showed an excellent fit (r &gt; 0.996) when described by a phenomenological model based on the Fermi equation, S(P) = 1/|1 + exp[(P − Pc)/k]|, where S(P) is the survival fraction, P is the pressure, Pc is a critical pressure corresponding to 50% survival, and k is a constant representing the steepness of the curve.

scholarly journals Acute and subacute toxicity tests of goat bile in BALB/c mice

2020 ◽  
Vol 13 (3) ◽  
pp. 515-520
Author(s):  
Heny Arwati ◽  
Windya T. Hapsari ◽  
Kartika A. Wardhani ◽  
Kholida N. Aini ◽  
Ramadhani R. Bahalwan ◽  
...  
Keyword(s):  
Body Weight ◽  
Toxicity Test ◽  
Harmful Effect ◽  
Negative Control ◽  
The Body ◽  
Toxicity Tests ◽  
Slight Reduction ◽  
Subacute Toxicity ◽  
Liver And Kidney ◽  
Hematology Parameters

Aim: The aim of this study was to investigate the toxicity of goat bile in BALB/c mice since some Indonesian people consume raw goat gallbladder to treat malaria and increase stamina. Materials and Methods: Acute toxicity test was done in six groups of BALB/c mice using 100%, 50%, 25%, 12.5%, and 6.75% of goat bile and negative control. The death of mice was observed within 14 days. In the subacute toxicity test, the body weight and hematology parameters on day 0 and day 4 post-treatment were evaluated. The mice were closely observed for 28 days before plasma collection for the blood biochemistry evaluation. Results: Mild diarrhea was observed in acute and subacute toxicity tests. No death of mice was observed in acute test. Goat bile did not inhibit the increase of the body weight of mice. A slight reduction in hemoglobin and hematocrit levels in mice treated with 25% and 50% goat bile, however, remained normal in mice treated with 100% goat bile. The red and white blood cell count were not affected. Liver and kidney functions were not affected by goat bile treatment as revealed by the plasma level of aspartate aminotransferase and alanine aminotransferase, blood urea nitrogen, and creatinine, which remained in the normal range. Conclusion: Goat bile treatment in BALB/c mice caused mild toxicity in mice. Hydrophobic bile acids may cause the toxicity of goat bile in mice; therefore, it is recommended that goat bile consumption not to be taken oftenly to avoid its harmful effect.

scholarly journals Influence of Simulated Pulpal Pressure on Efficacy of Bleaching Gels

2014 ◽  
Vol 15 (4) ◽  
pp. 407-412 ◽  
Author(s):  
Carlos Rocha Gomes Torres ◽  
Graziela Ribeiro Batista ◽  
Alessandra Bühler Borges ◽  
Paula Tamião Arantes ◽  
Annette Wiegand ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Artificial Saliva ◽  
Negative Control ◽  
Color Variation ◽  
Color Measurement ◽  
Control Group ◽  
Significant Difference ◽  
Bleaching Gels ◽  
Bleaching Treatment

ABSTRACT Aim The aim of this study was to investigate the influence of simulated pulpal pressure on efficacy of bleaching gels. Materials and methods Cylindrical enamel-dentin specimens from bovine teeth (3 mm diameter, enamel and dentin layer each 1 mm thick) were divided into 4 groups, according to the bleaching treatment: negative control (non-bleached), bleached with 10% carbamide peroxide (CP), bleached with 7.5% hydrogen peroxide (HP) and bleached with 35% hydrogen peroxide. Ten percent CP gel was applied for 8 h/day and 7.5% HP for 1 h/day, during 14 days. For 35% HP treatment, two sessions of 45 minutes each were employed. In intermediate periods specimens were stored in artificial saliva. Experimental groups (n = 19) were subdivided according to the simulation of pulpal pressure (25 mm Hg) during bleaching treatment. Initial color measurement and after bleaching treatment were assessed by spectrophotometry, using CIE L*a*b* system. The data were statistically analyzed by ANOVA and Dunnett's posthoc tests (p < 0.05). Results There was significant difference of ∆E for all experimental groups compared to negative control group, according to Dunnett's test (p < 0.0001). There were no significant difference for total color variation (∆E) among experimental groups (p > 0.05). Conclusion It was concluded that all bleaching gels showed bleaching efficacy compared to non-bleached group and that the simulated pulpal pressure did not influence the bleaching outcomes of the tested gels. Clinical significance Although numerous in vitro studies investigating the efficacy of bleaching agents have been performed, they do not properly simulate the pulpal pressure. In order to make these studies closer to clinical conditions, it is important to reproduce these conditions in laboratory, so the results can be more reliable. This in vitro study was performed under simulated pulpal pressure, aiming to investigate its influence on dental bleaching outcomes. How to cite this article Borges AB, Batista GR, Arantes PT, Wiegand A, Attin T, Torres CRG. Influence of Simulated Pulpal Pressure on Efficacy of Bleaching Gels. J Contemp Dent Pract 2014;15(4):407-412.

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