scholarly journals In Situ and In Vitro Effects of Two Bleaching Treatments on Human Enamel Hardness

2016 ◽  
Vol 27 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Sandrina Henn-Donassollo ◽  
Cristiane Fabris ◽  
Morgana Gagiolla ◽  
Ícaro Kerber ◽  
Vinícius Caetano ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oral Appliance ◽  
Water Cooling ◽  
Surface Microhardness ◽  
Tukey Test ◽  
Human Enamel ◽  
Before And After ◽  
In Vitro Effects

Abstract The aim of this study was to evaluate in vitro and in situ the effects of two bleaching treatments on human enamel surface microhardness. Sixty enamel slabs from recently extracted thirty molars were used. The specimens were polished with sandpapers under water-cooling. The enamel samples were randomly divided in four groups, treated with 10% hydrogen peroxide (HP) or Whitening Strips (WS) containing 10% hydrogen peroxide and using two conditions: in vitro or in situ model. For in situ condition, six volunteers wore an intra-oral appliance containing enamel slabs, while for in vitro condition the specimens were kept in deionized water after the bleaching protocols. The bleaching treatments were applied one-hour daily for 14 days. Similar amounts of bleaching agents were used in both conditions. Before and after bleaching treatments, microhardness was measured. Statistical analysis (ANOVA and Tukey test) showed that in the in situ condition there was no statistically significant microhardness reduction in the bleached enamel (p>0.05). Significant decrease in hardness was observed for enamel slabs bleached with both treatments in the in vitro condition (p<0.05). Regarding the bleaching agents, in situ results showed no difference between HP and WS, while in vitro WS produced the lowest hardness value. It could be concluded that there was no deleterious effect on enamel produced by any of the bleaching protocols used in the in situ model. The reduction of hardness was only observed in vitro.

scholarly journals Application of the MSAP Technique to Evaluate Epigenetic Changes in Plant Conservation

2020 ◽  
Vol 21 (20) ◽  
pp. 7459
Author(s):  
María Elena González-Benito ◽  
Miguel Ángel Ibáñez ◽  
Michela Pirredda ◽  
Sara Mira ◽  
Carmen Martín
Keyword(s):  
Dna Methylation ◽  
In Situ Conservation ◽  
Plant Conservation ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Regenerated Plants ◽  
Before And After ◽  
Methylation Patterns

Epigenetic variation, and particularly DNA methylation, is involved in plasticity and responses to changes in the environment. Conservation biology studies have focused on the measurement of this variation to establish demographic parameters, diversity levels and population structure to design the appropriate conservation strategies. However, in ex situ conservation approaches, the main objective is to guarantee the characteristics of the conserved material (phenotype and epi-genetic). We review the use of the Methylation Sensitive Amplified Polymorphism (MSAP) technique to detect changes in the DNA methylation patterns of plant material conserved by the main ex situ plant conservation methods: seed banks, in vitro slow growth and cryopreservation. Comparison of DNA methylation patterns before and after conservation is a useful tool to check the fidelity of the regenerated plants, and, at the same time, may be related with other genetic variations that might appear during the conservation process (i.e., somaclonal variation). Analyses of MSAP profiles can be useful in the management of ex situ plant conservation but differs in the approach used in the in situ conservation. Likewise, an easy-to-use methodology is necessary for a rapid interpretation of data, in order to be readily implemented by conservation managers.

scholarly journals Interleukin-6 and its receptor are expressed by human megakaryocytes: in vitro effects on proliferation and endoreplication

Blood ◽  
1991 ◽  
Vol 77 (3) ◽  
pp. 461-471 ◽  
Author(s):  
S Navarro ◽  
N Debili ◽  
JP Le Couedic ◽  
B Klein ◽  
J Breton-Gorius ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Interleukin 6 ◽  
Dot Blot ◽  
Autocrine Loop ◽  
Megakaryocytic Differentiation ◽  
Normal Human ◽  
In Vitro Effects ◽  
A Minor

Abstract Interleukin-6 (IL-6) is a pleiotropic cytokine that plays an important role in the megakaryocytic differentiation. Recently, we have observed that IL-6 is synthesized by several human cell lines with megakaryocytic features. In this study, we have investigated whether a similar phenomenon occurs during normal megakaryocytic differentiation. Human megakaryocytes (MK) were obtained by culturing normal marrow in liquid culture with aplastic plasma (AP). First, an IL-6 secretion in bone marrow culture enriched in MK as well as in purified MK populations was demonstrated by a biologic assay. Second, IL-6 mRNA was detected in a purified population of MK by the polymerase chain reaction and dot blot analysis. IL-6 mRNA and protein were undetectable in platelets. Third, in situ hybridization procedure demonstrated the presence of IL-6 mRNA in individual immature MK. Fourth, IL-6 protein was detected in MK at the unicellular level by an immunoalkaline phosphatase technique using a monoclonal antibody against IL-6. Furthermore, the presence of IL-6 receptor (IL-6-R) on MK was demonstrated by in situ hybridization using an IL-6-R probe and in situ autoradiography after binding with [125I]-labeled recombinant IL-6. The IL-6 endogenously produced in liquid cultures containing normal human plasma or AP was subsequently neutralized. This resulted in a 50% decrease of the MK growth with a minor shift in the ploidy distribution toward lower values. In semisolid cultures the addition of anti-IL-6 antibodies led to a 42% decrease in colony number in cultures stimulated by IL-3 but not in other conditions of culture. These results suggest that normal human megakaryocytopoiesis might be regulated in part by an IL-6 autocrine loop.

scholarly journals Genetic or pharmacological superoxide-hydrogen peroxide imbalances modulate the in vitro effects of lithium on glycogen synthase kinase-3β

Gene ◽  
2018 ◽  
Vol 655 ◽  
pp. 48-55 ◽  
Author(s):  
Fernanda Barbisan ◽  
Verônica Farina Azzolin ◽  
Gustavo Cardenas Monteiro ◽  
Cibele F. Teixeira ◽  
Moisés Henrique Mastella ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3Β ◽  
In Vitro Effects

scholarly journals In vitro Effects of Vitamin E on Hydrogen Peroxide

1973 ◽  
Vol 111 (1) ◽  
pp. 99-100
Author(s):  
OTOTAKA HIGASHI ◽  
YOKO KIKUCHI
Keyword(s):  
Hydrogen Peroxide ◽  
Vitamin E ◽  
In Vitro Effects

Anticaries Potential of Commercial Dentifrices as Determined by Fluoridation and Remineralization Efficiency

2007 ◽  
Vol 8 (7) ◽  
pp. 1-10 ◽  
Author(s):  
Elias Casals ◽  
Tchilalo Boukpessi ◽  
Christina M. McQueen ◽  
Sandy L. Eversole ◽  
Robert V. Faller
Keyword(s):  
Surface Hardness ◽  
Reference Standard ◽  
Surface Microhardness ◽  
Fluoride Uptake ◽  
Human Enamel ◽  
Demineralized Enamel ◽  
Group 6 ◽  
Group 3 ◽  
Group 2

Abstract Aim The aim of this in vitro study was to investigate fluoride uptake in human enamel after use of commercially available toothpastes containing different fluoride compounds, or combinations of fluoride actives formulated into a single product, as a means of determining the efficiency of each formula for delivering caries preventing fluoride to demineralized (caries active) enamel. Methods and Materials Four test dentifrices and two controls were assessed and placed in groups as follows: Group 1: Lacer® (Spain); Group 2: Positive control-USP Reference Standard 1100 ppm F; Group 3: Fluocaril® Bi-Fluoré 250 (France); Group 4: Colgate Fluor Active (Denmark); Group 5: Elmex® (France); and Group 6: A placebo (formulated the same as the USP Reference Standard toothpaste with the exception that it contained < 1 ppm F). Cores 3 mm in diameter were removed from erupted human enamel specimens (extracted by local oral surgeons for orthodontic reasons) and stored in 1% Thymol solution prior to use. They were ground and polished to remove the natural fluoride rich enamel layer, then exposed to a demineralization solution, and assessed for surface microhardness to enable randomization for use in the study. Each group of five specimens underwent a daily pH cycling procedure that involved exposure to pooled human saliva (refreshed three times daily). The groups were then exposed to dentifrice slurries four times daily for one minute per exposure and to a demineralization solution for three hours. The cycling procedure was repeated for five days. Specimens were again analyzed for surface microhardness and fluoride uptake upon completion of five days of treatment. Results Average surface hardness: Groups 2 and 3 showed a statistically significant greater (p<0.05) change indicating greater remineralization compared to all other groups. The average change was 23.45 for Group 2 and 22.65 for Group 3. All other groups had changes ranging from 4.25-8.62. No other statistically significant differences were observed between groups. Fluoride uptake results: Groups 2 and 3 showed statistically significantly greater fluoride uptake versus all other groups (p <0.05). Groups 1 and 5 were significantly different from Group 6. No other statistically significant differences were observed for either analysis. Conclusions Of the marketed products included in the study, the Fluocaril® Bi-Fluoré 250 product formulation provided both the highest level of fluoride uptake and mineralization to the demineralized enamel. The clinical significance of these in vitro results is the confirmation Fluocaril® Bi-Fluoré 250 is effective at remineralizing enamel caries lesions. Citation Casals E, Boukpessi T, McQueen CM, Eversole SL, Faller RV. Anticaries Potential of Commercial Dentifrices as Determined by Fluoridation and Remineralization Efficiency. J Contemp Dent Pract 2007 November; (8)7:001-010.

Remineralization Potential of a New Toothpaste Formulation: An In-Vitro Study

2004 ◽  
Vol 5 (1) ◽  
pp. 18-30 ◽  
Author(s):  
Carlos A. Muñoz ◽  
Anna Torrado ◽  
Manuel Valiente ◽  
Wu Zhang ◽  
Yiming Li
Keyword(s):  
Ion Exchange ◽  
In Vitro Study ◽  
Ion Exchange Resin ◽  
Ion Exchange Resins ◽  
Experimental Conditions ◽  
Human Enamel ◽  
Before And After ◽  
Ph Cycling ◽  
Exchange Resins

Abstract The aim of the present study was to determine the ability of a dentifrice containing a mixture of ion-exchange resins (named NMTD), which supplies calcium, fluoride, phosphate, and zinc ions, to promote remineralization and/or inhibit demineralization of dental human enamel in a pH cycling model in vitro. A fluoride toothpaste was used as the control. The enamel specimens were tested for microhardness before and after 10 days and 16 days of the demineralizing and remineralizing treatments. The results of this study showed both dentifrices were effective in limiting in vitro enamel demineralization although the effects were not significantly different from each other. Inclusion of calcium and phosphate ion-exchange resins in the dentifrice containing a fluoride ion-exchange resin maintained a similar net outcome of the conventional dentifrice in the demineralization/ remineralization process under the experimental conditions employed. Citation Torrado A, Valiente M, Zhang W, et. al. Remineralization Potential of a New Toothpaste Formulation: An In-Vitro Study. J Contemp Dent Pract 2004 February;(5)1:018-030.

scholarly journals Effect of a carbamide peroxide bleaching gel containing calcium or fluoride on human enamel surface microhardness

2005 ◽  
Vol 16 (2) ◽  
pp. 103-106 ◽  
Author(s):  
Rogério de Oliveira ◽  
Adriana Franco Paes Leme ◽  
Marcelo Giannini
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Enamel Surface ◽  
Control Group ◽  
Carbamide Peroxide ◽  
Surface Microhardness ◽  
Treatment Groups ◽  
Peroxide Bleaching ◽  
Human Enamel

This in vitro study evaluated the surface microhardness of human enamel submitted to bleaching with 10% carbamide peroxide (CP) containing calcium or fluoride. Ninety-eight dental blocks (5 x 5 mm²) with polished enamel surfaces were randomly assigned to 7 treatment groups (n=14), as follows: without bleaching and storage in artificial saliva (control); 10% CP; 10% CP + 0.05% calcium; 10% CP + 0.1% calcium; 10% CP + 0.2% calcium; 10% CP + 0.2% fluoride; and 10% CP + 0.5% fluoride. During 14 days, enamel surfaces were daily exposed to a 6-h bleaching regimen followed by storage in artificial saliva. Surface microhardness was measured before (baseline), during (7th day), immediately after bleaching (14th day) and 1 week post bleaching. Data were analyzed by two-way ANOVA and Tukey's test (p<0.05). All treatments reduced SM significantly during the bleaching cycle (7th day), immediately after bleaching (14th day) and 1 week post bleaching, compared to baseline and to the unbleached control group. In conclusion, in spite of the addition of calcium and fluoride, all bleaching treatments affected the enamel surface microhardness.

scholarly journals STUDIES ON THE RIGOR RESULTING FROM THE THAWING OF FROZEN FROG SARTORIUS MUSCLE

1950 ◽  
Vol 33 (5) ◽  
pp. 563-577 ◽  
Author(s):  
S. V. Perry
Keyword(s):  
Hydrogen Peroxide ◽  
Iodoacetic Acid ◽  
Sartorius Muscle ◽  
Fixed Length ◽  
Frog Sartorius Muscle ◽  
Vitro Effect ◽  
Resting Muscle ◽  
Frog Sartorius

1. The rigor which takes place when completely frozen frog sartorius muscle is thawed ("thaw rigor"), is accompanied by a decrease in length of 70 per cent and a loss in weight of 35 per cent, whether the muscle is frozen in the resting or the exhausted condition, or during isometric tetanus. Muscle tetanized to maximal shortening shows a loss in weight of 25 per cent on thawing. 2. A load of 8 gm. is sufficient to prevent the decrease in length on thawing, but after its removal the muscle will shorten almost to the normal extent. 3. Inhibitors such as azide, cyanide, 2:4 dinitrophenol, p-chloromercuribenzoate, Cu, and hydrogen peroxide, when used for periods not exceeding 1 hour, have little effect on the shortening; although in some cases these poisons render the muscle inexcitable. 4. Muscles poisoned with iodoacetic acid and stimulated to exhaustion, or maintained at fixed length in nitrogen, show little or no shortening on thawing. ATP can produce shortening in the muscles in which it has been prevented. 5. The phenomenon is considered to be due to an in situ synaeresis of the actomyosin of the myofibrils. As a result of the disorganisation of the muscle protoplasm produced by the freezing and subsequent thawing, the ATP, which must be bound or localized in the resting muscle, can act on the myofibril in a similar manner to its in vitro effect on the actomyosin thread.

scholarly journals In vitro effects of alcohol-containing mouthwashes on human enamel and restorative materials

2018 ◽  
Vol 32 (0) ◽  
Author(s):  
José Eduardo Pelizon PELINO ◽  
Alan PASSERO ◽  
Airton Abrahao MARTIN ◽  
Christine Ann CHARLES
Keyword(s):  
Human Enamel ◽  
Restorative Materials ◽  
In Vitro Effects
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