37 CELL CYCLE ANALYSIS IN IN VITRO-CULTURED ADULT SKIN FIBROBLASTS OF THE GORAL (NAEMORHEDUS CAUDATUS)

2006 ◽  
Vol 18 (2) ◽  
pp. 127
Author(s):  
M. A. Hashem ◽  
P. B. Dilip ◽  
S. K. Kang ◽  
B. C. Lee ◽  
W. S. Hwang
Keyword(s):  
Cell Cycle ◽  
Cytochalasin B ◽  
Positive Impact ◽  
Statistical Significance ◽  
Skin Fibroblasts ◽  
Nuclear Transplantation ◽  
Serum Starvation ◽  
Significant Difference ◽  
Adult Skin

The present study was undertaken to examine the cell cycle characteristics of goral adult skin fibroblasts under a variety of cell cycle-arresting treatments. Gorals are listed as an endangered animal in CITES Appendix I. Experimental findings suggest that G0/G1 stages of the cell cycle give better results in somatic cell nuclear transfer (SCNT) in terms of normal ploidy and development of reconstructed embryos. In this regard, synchronization of the cell cycle stages in G0/G1 phase is suggested to be one of the key factors for determining the success of nuclear transplantation. Serum deprivation, contact inhibition, chemical inhibitors such as protease, and antioxidant inhibitors are widely used for cell cycle synchronization and inhibition of apoptosis. Four experiments were performed, and each with one-way completely randomized design involving three replicates of all treatments using the general linear models procedure in the statistical analysis system (SAS Institute, Inc., Cary, SC, USA). Least significant difference was used to determine statistical significance (P < 0.05) among treatment groups. In Exp. 1, effects of cyclic confluency, serum starvation, or full confluency on goral cells were studied. In Exp. 2, treatments with different antioxidants such as 2 mM beta-mercaptoethanol (B-ME), cysteine, or glutathione for 24 h were examined in fully confluent cells without serum starvation. In Exp. 3, three protein inhibitors, 2 mM 6-dimethylaminopurine (6-DMAP), 7.5 �g/mL cycloheximide, or 7.5 �g/mL cytochalasin B, were treated as in Exp. 2. In Exp. 4, different concentrations (0, 0.5, 1.0, or 2.5%) of dimethyl sulfoxide (DMSO) were treated as in Exp. 2. In all experiments, cell cycle stages were analyzed by fluorescence-activated cell sorting (FACS) analysis. In Exp. 1, more cells (70.4%) were found in the G0/G1 stage in the serum starved medium compared to cells in the cyclic (66.1%) and fully confluent growth phase (65.5%). In Exp. 2, supplementing with B-ME (61.8%) or cysteine (62.0%) in the culture medium synchronized cell cycle to the G0/G1 stage better than glutathione (53.1%). In Exp. 3, more cells were synchronized to the G0/G1 stage in media supplemented with cyclohexamide (62.3%) than with 6-DMAP (5.7%) or cytochalasin B (13.3%). Incidence of apoptosis was higher in media containing 6-DMAP (91.8%) or cytochalasin B (76.6%). In Exp. 4, supplementing the medium with 0.5% (76.0%) or 1.0% (75.9%) DMSO synchronized the cells effectively to the G0/G1 stage compared to the untreated control medium (69.3%) or medium supplemented with 2.5% of DMSO (8.0%). In conclusion, cyclohexamide, B-ME, cysteine, or DMSO at the optimum concentration can synchronize the cell cycle effectively, which may have a positive impact on the outcome of SCNT in the goral. This study was supported by grants from the Korean MOST (Top Scientist Fellowship) and MAF (Biogreen 21 #20050301-034-443-026-04-00).

Cell cycle analysis of in vitro cultured goral (Naemorhedus caudatus) adult skin fibroblasts

2006 ◽  
Vol 30 (9) ◽  
pp. 698-703 ◽  
Author(s):  
M HASHEM ◽  
D BHANDARI ◽  
S KANG ◽  
B LEE ◽  
H SUK
Keyword(s):  
Cell Cycle ◽  
Skin Fibroblasts ◽  
Cell Cycle Analysis ◽  
Adult Skin

scholarly journals Introducing intrauterine antibiotic infusion as a novel approach in effectively treating chronic endometritis and restoring reproductive dynamics: a randomized pilot study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Konstantinos Pantos ◽  
Mara Simopoulou ◽  
Evangelos Maziotis ◽  
Anna Rapani ◽  
Sokratis Grigoriadis ◽  
...  
Keyword(s):  
Fertility Restoration ◽  
Statistical Significance ◽  
Antibiotic Administration ◽  
Oral Antibiotic ◽  
Treatment Rate ◽  
Chronic Endometritis ◽  
Vitro Fertilization ◽  
Significant Difference ◽  
Antibiotic Infusion

AbstractThe chronic nature of Chronic Endometritis (CE) along with the challenging management and infertility entailed, call for cutting-edge therapeutic approaches. This study introduces the novel treatment of intrauterine antibiotic infusion (IAI) combined with oral antibiotic administration (OAA), and it assesses respective performance against the gold standard treatment of OAA. Data sourced herein reports on treatment efficiency and fertility restoration for both patients aiming to conceive naturally or via In Vitro fertilization. Eighty CE patients, 40 presenting with recurrent implantation failure, and 40 with recurrent pregnancy loss, were enrolled in the IVF and the natural conception arm respectively. Treatment was subjected to randomization. Effectively treated patients proceeded with either a single IVF cycle or were invited to conceive naturally over a 6-month period. Combination of IAI and OAA provided a statistically significant enhanced effectiveness treatment rate (RR 1.40; 95%CI 1.07–1.82; p = 0.01). No statistically significant difference was observed regarding the side-effects rate (RR 1.33; 95%CI 0.80–2.22; p = 0.52). No statistically significant difference was observed for either arm regarding live-birth rate. Following an intention-to-treat analysis, employment of IAI corresponds to improved clinical pregnancy rate-albeit not reaching statistical significance. In conclusion, complimentary implementation of IAI could provide a statistically significant enhanced clinical treatment outcome.

Efficient reactivation of Xenopus erythrocyte nuclei in Xenopus egg extracts

1995 ◽  
Vol 108 (6) ◽  
pp. 2187-2196 ◽  
Author(s):  
L.J. Wangh ◽  
D. DeGrace ◽  
J.A. Sanchez ◽  
A. Gold ◽  
Y. Yeghiazarians ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Somatic Cell ◽  
Nuclear Transplantation ◽  
Optimal Time ◽  
Genome Replication ◽  
Cell Nuclei ◽  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts

Rapid genome replication is one of the hallmarks of the frog embryonic cell cycle. We report here that complete reactivation of quiescent somatic cell nuclei in Xenopus egg extracts depends on prior restructuring of the nuclear substrate and prior preparation of cytoplasmic extract with the highest capacity to initiate and sustain DNA synthesis. Nuclei from mature erythrocytes swell, replicate their DNA efficiently, and enter mitosis in frozen/thawed extracts prepared from activated Xenopus eggs, provided the nuclei are first treated with trypsin, heparin, and an extract prepared from unactivated, meiotically arrested, eggs. Optimal replicating extracts are prepared from large batches of unfertilized eggs that are synchronously activated into the cell cycle for 28 minutes (at 20 degrees C). Because the Xenopus cell cycle progresses so rapidly, extracts prepared just a few minutes before or after this time have substantially lower DNA synthetic capacities. At the optimal time and temperature, eggs have just reached the G1/S boundary of the first cell cycle. This fact was revealed by injecting and replicating an SV40 plasmid in intact unfertilized eggs as described previously. We estimate that under optimal conditions approximately 6.14 × 10(9) base pairs of DNA/per nucleus are synthesized in 30–40 minutes, a rate that rivals that observed in the zygotic nucleus. The findings reported here are one step in our long term effort to develop a new in vitro/in vivo approach to nuclear transplantation. Nuclear transplantation in amphibian embryos has been used to establish that the genomes of many types of differentiated somatic cells are pluripotent. But very few such nuclei have ever developed into advanced tadpoles or adult frogs, probably because somatic nuclei injected directly into activated eggs fail to reactivate quickly enough to avoid being damaged during first mitosis. We have already shown that unfertilized eggs can be injected prior to activation of the first cell cycle. Future experiments will reveal whether in vitro reactivated somatic cell nuclei transplanted into such eggs reliably reach advanced stages of development.

scholarly journals 64COMPARISON OF DEVELOPMENTAL POTENTIAL OF IN VIVO AND IN VITRO RECIPIENT OOCYTES AFTER NUCLEAR TRANSFER IN GOAT

2004 ◽  
Vol 16 (2) ◽  
pp. 154
Author(s):  
H.S. Park ◽  
M.Y. Lee ◽  
S.P. Hong ◽  
J.I. Jin ◽  
J.K. Park ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Electric Pulse ◽  
Serum Starvation ◽  
Cleavage Rate ◽  
Developmental Potential ◽  
In Vitro Development ◽  
Significant Difference ◽  
Vitro Development

Recent techniques in somatic cell nuclear transfer (SCNT) have been widely used for animal research. In addition, SCNT techniques may allow for the rescue of endangered species. Despite efforts for wildlife preservation, however, some threatened or endangered wild animal species will likely become extinct. As a preliminary experiment of a series in wildlife research, we tried to identify an improved method for the production of more transferable NT embryos in goats. Mature donor animals of Korean native goats (20–25kg) were synchronized with a CIDR (type G; InterAg, New Zealand) vaginal implant for 10 days followed by a total of 8 twice daily injections of 70mg of FSH (Folltropine, London, Ontario, Canada) and 400IU of hCG (Chorulon, Intervet, Moxmeer, The Netherlands). Oocytes were then collected surgically by retograde oviduct flush or direct aspiration from ovarian follicles in vivo at 29–34h after hCG. Oocytes collected from follicles were matured in TCM-199 containing 10% FBS and hormones. Prepared ear skin cells from the goat were cultured in TCM-199 containing 10% FBS at 39°C, 5% CO2 in air, and confluent monolayers were obtained. Oocytes were enucleated and donor cells from serum starvation (0.5%) culture were fused through a single electric pulse (DC 2.36kvcm−1, 17μs), and then activated by a single electric pulse (AC 5vmm−1, 5s+DC 1.56kvcm−1, 30μs) or chemical treatment (5μgmL−1 ionomycin 5min−1, 1.9mM 6-DMAP/4h). Reconstructed oocytes were cultured in M16 medium with 10% goat serum (GS) for 6–7 days. Data were analyzed by chi-square test. In in vitro development, significantly (P&lt;0.05) more oocytes were cleaved (24/30, 80.0%) and developed (7/24, 29.2%) to morula or blastocyst stage, respectively, in NT oocytes activated by Iono + DMAP compared to electric stimulated oocytes (2/21, 40.0%; 0/2, 0%). There was a significant difference in in vitro development of NT embryos by the method of oocyte collection. Cleavage rate was higher (P&lt;0.05) in NT embryos from in vivo oocytes (23/28, 82.1%) than in in vitro matured oocytes (19/35, 54.3%), and further development to morula or blastocyst was also significantly (P&lt;0.05%) higher in NT embryos from in vivo oocytes (7/23, 30.4%) than in NT embryos from in vitro matured oocytes (0/19, 0%). When we compared NT embryos to parthenotes, developmental rate was not significantly different between NT embryos and parthenotes. These results strongly suggest that the in vivo oocytes will have superior developmental potential to oocytes matured in vitro. Table 1 Effect of different oocyte source on in vitro development following caprine SCNT

Type II pneumocyte hypertrophy without activation of surfactant biosynthesis after partial pneumonectomy

1993 ◽  
Vol 264 (2) ◽  
pp. L153-L159 ◽  
Author(s):  
B. D. Uhal ◽  
M. D. Etter
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Tritiated Thymidine ◽  
Cell Cycle Distribution ◽  
Type Ii ◽  
Adult Rats ◽  
Type Ii Pneumocyte ◽  
Significant Difference

Hypertrophic and normotrophic type II pneumocytes were isolated from pneumonectomized adult rats by unit gravity (1 g) sedimentation or by fluorescence-activated cell sorting (FACS). In vivo or in vitro, hypertrophic cells incorporated significantly more 5-bromo-2'-deoxyuridine or tritiated thymidine into acid-insoluble material than did normotrophic cells. By FACS analysis of cell subpopulations isolated by 1 g, > 97% of normotrophic cells had G0-phase DNA content. In contrast, the cell cycle distribution of hypertrophic cells was 75% G1, 5% S, and 20% G2/M phases. Rates of incorporation of tritiated choline into total cellular phosphatidylcholine (PC) were identical in type II cells isolated from normal or pneumonectomized rats. The intracellular contents of disaturated phosphatidylcholine (DSPC) and total PC, as well as the ratio of these two lipids, were the same in hypertrophic and normotrophic cells from pneumonectomized rats and in cells isolated from normal rats. No significant difference was observed in the rate at which hypertrophic or normotrophic cells incorporated choline into DSPC. These results demonstrate that type II pneumocyte hypertrophy after pneumonectomy reflects balanced cell growth secondary to cell cycle progression in vivo. The data also indicate that epithelial cell hypertrophy after pneumonectomy, in contrast to that which develops after more acute lung injury, occurs without activation of surfactant biosynthesis or storage.

CEP701 and PKC412 Predictably and Reliably Inhibit FLT3 Phosphorylation in Primary AML Blasts but Their Induction of a Cytotoxic Response Appears to Be Much More Variable.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 95-95 ◽  
Author(s):  
Steven Knapper ◽  
Alan K. Burnett ◽  
Amanda F. Gilkes ◽  
Kenneth I. Mills ◽  
Val Walsh
Keyword(s):  
Statistical Significance ◽  
Annexin V ◽  
Expression Level ◽  
Wild Type ◽  
Response Curves ◽  
Allele Ratio ◽  
Cytotoxic Response ◽  
Significant Difference ◽  
Flt3 Expression

Abstract Activating mutations of the receptor tyrosine kinase FLT3 are present in approximately one-third of AML cases and are associated with an adverse prognosis. FLT3 is expressed in over 90% of cases of AML and many non-mutants show evidence of FLT3 activation, which may play a significant signalling role in leukaemogenesis, making FLT3 an attractive therapeutic target. CEP701 (Cephalon) and PKC412 (Novartis) are orally-bioavailable indolocarbazole derivatives that potently inhibit FLT3 phosphorylation. We studied the relationship between in vitro inhibition of FLT3 phosphorylation and induction of cytotoxicity in primary AML blasts from 12 patients. 7 of the cases were FLT3 mutants (6 ITDs and 1 D835 point mutant), the amount of mutant RNA varying between 7% and 84% of total FLT3 RNA expressed. The blasts were exposed for 1 hour to a range of concentrations of CEP701 and PKC412, lysed and immunoprecipitated with an anti-FLT3 antibody. After sequential immunoblotting with anti-phosphotyrosine and anti-FLT3 antibodies, inhibition of FLT3 phosphorylation was measured by densitometry. Both drugs inhibited FLT3 phosphorylation in all samples with lower concentrations required in FLT3 mutants. CEP701 inhibited FLT3 phosphorylation with median IC50s of 3.7nM and 11.9nM in mutant and wild type (WT) cases respectively (p=0.0006). IC50s for PKC412 were 7.7nM and 59.8nM in mutant and WT cases (p=0.0268). Induction of cytotoxicity was assessed by MTS assay following 72-hour exposure of blasts to a range of concentrations of CEP701 and PKC412. Cytotoxic responses to both drugs were greater in FLT3 mutants than WT cases at each dose studied and in terms of IC50 dose (median IC50s in mutant and WT cases: 95nM and 231nM with CEP701, 1.24 μM and 1.61μM with PKC412) although these differences did not reach statistical significance. Annexin V binding apoptosis assay produced similar dose response curves. Both agents showed greater inter-case variability in cytotoxic response than in sensitivity to inhibition of FLT3 phosphorylation. A lack of cytotoxic response to FLT3 inhibition with CEP701 was seen in the ITD mutant with the lowest ratio of mutant to WT FLT3 RNA (0.08) and several WT samples displayed resistance to in vitro induction of cytotoxicity despite almost complete inhibition of FLT3. Induction of cytotoxicity with PKC412 in both mutant and WT cases generally required doses well in excess of those required to fully inhibit FLT3 phosphorylation. Cases were further stratified by flow cytometric measurement of surface FLT3 expression, and by immunoblotting to measure STAT5 dephosphorylation in response to both drugs. No significant difference in overall FLT3 expression was seen between mutant and WT cases. Interestingly the highest FLT3 expression level was seen in a wild type case that was highly sensitive to CEP701. Inhibition of STAT5 phosphorylation appeared closely linked to FLT3 inhibition, although in some cases a good cytotoxic response was achieved despite failure to inhibit STAT5, suggesting involvment of other signalling pathways. In summary, although both CEP701 and PKC412 predictably and reliably inhibit FLT3 phosphorylation in primary AML blasts, their induction of cytotoxicity appears to be much more variable. A number of factors may influence this including variations in level of dependency on FLT3 signalling for blast survival, mutant to WT allele ratio and overall FLT3 expression level. Effects on targets other than FLT3 also need to be considered.

Priming Effect with G-CSF Enhances In Vitro Apoptosis by Treatment with Ara-C and VP-16 in Leukemic Cell Line.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4333-4333
Author(s):  
Jun-ichi Kitagawa ◽  
Takeshi Hara ◽  
Hisashi Tsurumi ◽  
Nobuhiro Kanemura ◽  
Masahito Shimizu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Priming Effect ◽  
Low Dose ◽  
Combined Treatment ◽  
Annexin V ◽  
Leukemic Cell ◽  
Leukemic Cells ◽  
Significant Difference

Abstract Introduction: We have recently reported that the effectiveness of low dose Ara-C, VP-16 and G-CSF (AVG therapy) for elderly AML patients who were ineligible for intensive chemotherapy (Hematol Oncol, in press). G-CSF has been reported to potentiate in vitro anti-leukemic effect of Ara-C. The mechanism of the potentiation is assumed to recruit quiescent G0 leukemic cells into cell cycle. We hypothesized that the enhanced cytotoxicity was due to the apoptosis by the effect of the priming of G-CSF, and the effect was depended on the cell cycle. In order to afford proof of this hypothesis, we assayed proliferation, apoptosis, and cell cycle in leukemic cell lines. Materials: Ara-C, VP-16, G-CSF was provided by Nippon Shinyaku, Nihonkayaku, Chugai pharmacy, respectively, Tokyo, Japan. 32D and HL-60 were obtained from RIKEN Bioresource Center Cell Bank (Ibaragi, Japan), Ba/F3 was generous gifts from Dr. Kume, Jichi medical school, Tochigi, Japan. Methods: 5 x 105/ml HL60, 32D and Ba/F3 were cultured with various concentrations of Ara-C and/or VP-16 in the presence or absence of G-CSF 50ng/ml for 3 days. At the end of the culture, cell proliferation and viability were determined by using the trypan blue. The Annexin V-binding capacity of treated cells was examined by flow cytometry using ANNEXIN V-FITC APOPTOSIS DETECTION KIT I purchased from BD Pharmingen™. Cell cycle analysis was done with BrdU Flow KIT purchased from BD Pharmingen™. The incorporated BrdU was stained with specific anti-BrdU fluorescent antibodies, and the levels of cell-associated BrdU are then measured by flow cytometory. Result: Ara-C and VP-16 inhibited proliferation and decreased viability of leukemic cell lines dose-dependently. Half killing concentration (IC50) was redused in combination of Ara-C and VP-16 than Ara-C or VP-16 alone. In G-CSF dependent cell line (32D), IC50 was redeced in the presence of G-CSF than absence of G-CSF at G-CSF, and there was no significant difference between with and without G-CSF in G-CSF independent cell lines (HL-60, Ba/F3) (p<0.05). In combined treatment of low dose Ara-C (10−7M) and VP-16 (10−7M), the percentage of apoptotic cells were increased to 20.67% from 13.04% by addition of G-CSF in 32D, and there was no significant differencebetween with and without G-CSF in HL-60 and Ba/F3 (p<0.05). At combined treatment of low dose Ara-C and VP-16, the percentage of G0/G1 phase cells were decreased to 43.94% from 35.63% and S phase cells were increased to 29.50% from 24.05% in 32D by addition of G-CSF, and there was no significant difference between with and without G-CSF in HL-60 and Ba/F3 (p<0.05). Discussion: We first showed a combination effect of Ara-C and VP-16. Next we demonstrated that the potentiation of the cytotoxicity was mediated through the mechanism of apoptosis, and apoptosis played an important role for eradicating leukemic cells by low dose Ara-C and VP-16. And G-CSF recruited cells G0/G1 phase into S phase in G-CSF dependent cells by addition of G-CSF. These results suggest that priming effect of G-CSF significantly potentiate the cytotoxicity mediated by AVG chemotherapy. Conclusion: The priming effect of G-CSF might be admitted at least of a part in AML cells.

Effect of lenalidomide on the response of bladder cancer to BCG immunotherapy in an in vivo murine model.

2012 ◽  
Vol 30 (5_suppl) ◽  
pp. 288-288
Author(s):  
Eugene K. Lee ◽  
Jinesh Gerald ◽  
Ashish M. Kamat
Keyword(s):  
Cell Cycle ◽  
Bladder Cancer ◽  
Western Blotting ◽  
Murine Model ◽  
Statistical Significance ◽  
Combination Group ◽  
Control Group ◽  
Immunomodulatory Agent

288 Background: Intravesical BCG is the gold standard for non-muscle-invasive bladder cancer (NMIBC). However, many patients do not respond to therapy while others relapse and/or progress. As a result, there remains a need for therapies that can enhance the efficacy of BCG. We explore the efficacy of lenalidomide, an immunomodulatory agent used in multiple myeloma and myelodysplastic syndrome, in combination with BCG in vitro and in an in vivo bladder cancer model. Methods: We studied the effects of lenalidomide in combination with BCG induced cytokines in MBT-2 cells using PI-FACS. For in vitro studies, we used 10 and 100 nM of lenalidomide in combination with TNF-a and FasL. We then performed Western blotting for cell cycle and apoptosis regulatory proteins. Subsequently, we tested the efficacy of this combination in an immunocompetent murine model of bladder cancer with MBT-2 cells in C3H mice using the flank injection method. Drug dosages were 30 mg/kg for lenalidomide and 105 CFU of BCG. Tumor growth curves were created for the control, lenalidomide, BCG and combination treatment mice groups. Immunohistochemistry (IHC) was then performed using antibodies against proteins related to cell cycle, apoptosis, angiogenesis and immune response. Results: PI-FACS identified increased DNA fragmentation in the combinations of lenalidomide and TNF-a and FasL compared to control and each agent alone. Using Western blotting, we demonstrated that the combination resulted in apoptosis via caspase-3 activation. In the murine model, combination therapy resulted in a statistically significant decreased tumor size compared to the control group. While the BCG alone and lenalidomide alone groups did show a trend toward smaller tumor, they did not reach statistical significance. Furthermore, the TUNEL assay showed a substantial increase in apoptosis only in the combination group. Immunohistochemistry demonstrated decreased angiogenesis in all treatment groups compared to control, as well as, decreased T-cell infiltration. Conclusions: Our study demonstrates a potential role for the immunomodulatory agent, lenalidomide, in combination with BCG for NMIBC. This in vivo model serves as a template for future clinical trials.

scholarly journals A Comparative in Vitro Study of Power Output Deterioration over Time Between Ho:YAG Laser Fibers from Different Manufacturers as a Function of Deflection and Power Input

2015 ◽  
Vol 9 (1) ◽  
pp. 12-18
Author(s):  
Andreas Bourdoumis ◽  
Panagiotis Christopoulos ◽  
Nirmal Raj ◽  
Artemis Fedder ◽  
Noor Buchholz
Keyword(s):  
Power Output ◽  
Fiber Type ◽  
Statistical Significance ◽  
In Vitro Study ◽  
Power Input ◽  
Energy Output ◽  
Fiber Fracture ◽  
Significant Difference ◽  
Continuous Use

Objectives: To investigate the performance of laser fibers from 6 major manufacturers in vitro and to identify the effect of time and angulations (180° and 0°) on fiber power output. Materials and Methods: Overall, 36 single-use fibers were used. Each was tested with an energy input of 0.8, 1.4 and 2.0 Joules. A power detector measured power output after 1, 5, 10 and 15 minutes for three 15-minute cycles of continuous use. For the first 2 cycles, the fiber was bent to 180° with the use of a pre fabricated mould. Analysis of the data was performed by ANOVA and Tukey's test when the results were significant amongst groups. Statistical significance was deemed p < 0.05. Results: No fiber fracture occurred. There was no significant difference in output at 15 minutes of continuous use at 0° and 180°. The reduction in energy output at the 15th minute of continuous use at 180° was not significant for any fiber type or initial input. Only output differences between the fibers proved to be significant (p = 0.001). Conclusion: Fiber fracture and decline in performance is not due to deflection and continuous use. Frictional forces that occur between the fiber tip and the stone fragments may be responsible.

scholarly journals INFLUÊNCIA DA MODIFICAÇÃO DA BASE DE COLAGEM E DA CONTAMINAÇÃO SALIVAR NA RESISTÊNCIA DE UNIÃO DE TUBOS ORTODÔNTICOS COLADOS AO ESMALTE HUMANO

2021 ◽  
Vol 58 (1) ◽  
pp. eUJ3657
Author(s):  
Germano Brandão ◽  
◽  
Liliana Ávila Maltagliati ◽  
Ana Carla Raphaelli Nahás-Scocate ◽  
Murilo Matias ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Statistical Significance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Metal Mesh ◽  
Human Teeth ◽  
Significance Level ◽  
Significant Difference

The objective of this in vitro study was to assess and compare the shear bond strength of conventional and modified orthodontic tubes bonded to the surface of dry and saliva-contaminated enamel. The sample consisted of 40 human teeth, which were randomly divided into four groups according to attachment base and presence or absence of saliva contamination as follows: Group CB, conventional orthodontic tubes without salivary contamination; Group CB-S, conventional orthodontic tubes with salivary contamination; Groups BM, orthodontic tubes modified by welding a metal mesh to their base without salivary contamination; and Group BM-S, modified orthodontic tubes with salivary contamination. Shear bond strength test was performed in a universal testing machine and analysis of the adhesive remnant index (ARI) by optical microscopy. Two-way ANOVA was used, followed by Tukey’s test at a statistical significance level of 5%. The ARI results were analysed descriptively. There was statistically significant difference between the groups regarding the shear bond strength values, with conventional tubes presenting significantly higher values (P < 0.05). In addition, the presence of salivary contamination interfered negatively with the behaviour of conventional tubes only (P < 0.05). Shear bond strength was not improved by increasing the area of the orthodontic tubes. Moreover, salivary contamination influenced negatively the SBS values, but only when conventional tubes were used.

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