Adhesive performance of dentin bonding agents applied in vivo and in vitro. Effect of intrapulpal pressure and dentin depth

The purpose of this study was to evaluate the influence of intrapulpal pressure and dentin depth on bond strengths of an etch-and-rinse and a self-etching bonding agent to dentin in vitro and in vivo. Twenty-four pairs of premolars were randomly divided into four groups (n = 6) according to the dentin bonding agent, Single Bond and Clearfil SE Bond, and intrapulpal pressure, null or positive. Each tooth of the pair was further designated to be treated in vivo or in vitro. The intrapulpal pressure was controlled in vivo by the delivery of local anesthetics containing or not a vasoconstrictor, while in vitro, it was achieved by keeping the teeth under hydrostatic pressure. Class I cavities were prepared and the dentin bonding agents were applied followed by incremental resin restoration. For the teeth treated in vitro, the same restorative procedures were performed after a 6 month-storage period. Beams with I mm 2 cross-sectional area were prepared and, microtensile tested. Clearfil SE Bond was not influenced by any of the variables of the study, while bond strengths produced in vitro were significatly higher for Single Bond. Overall, lower bond strengths were produced in deep dentin, which reached statistical significance when Single Bond was applied under physiological or simulated intrapulpal pressure. In conclusion, in vitro bonding may overestimate the immediate adhesive performance of more technique-sensitive dentin bonding systems. The impact of intrapulpal pressure on bond strength seems to be more adhesive dependent than dentin morphological characteristics related to depth. (C) 2007 Wiley Periodicals, Inc.

Differential response of the luteal phase and fertility in cattle following ovulation of the first-wave follicle with human chorionic gonadotropin or an agonist of gonadotropin-releasing hormone

A series of experiments with Holstein heifers was conducted to develop the capability of inducing accessory corpus luteum (CL) with a GnRH agonist (Buserelin, 8 mu g; GnRHa) or hCG; (3,000 IU) to increase plasma progesterone concentrations (Exp. 1, 2, and 3) and to test whether induction of accessory CL with hCG will increase conception rates in heifers (Exp. 4) and lactating cows (Exp. 5). In Exp. 1, heifers were treated on d 5 after estrus with GnRHa (n = 8) or saline (n = 7); heifers in Exp. 2 received hCG (n = 5) or saline (n = 4) on d 5. Experiment 3 allowed a contemporary evaluation of heifers treated on d 5 with GnRHa (n = 6), hCG (n = 6), saline (n = 6), or GnRHa at d 5 and hCG at the time of the induced ovulation (n = 5). The GnRHa and hCG were equally effective in inducing an accessory CL (93% induction rate), but the subsequent increase in progesterone concentrations was greater in hCG-treated heifers. A greater half life of hCG may provide longer LH-like stimulation of the first-wave follicle and subsequent developing accessory CL or a greater luteotropic effect on the original CL. Induction of an accessory CL with hCG on d 5 or 6 after insemination did not increase pregnancy rates in fertile heifers (Exp. 4: hCG = 64.8% vs control = 62.9%; n = 243) or lactating dairy cows during summer heat stress (Exp. 5: hCG = 24.2% vs control = 23.5%; n = 201).

An In Vitro Comparison of Different Cementation Strategies on the Pull-out Strength of a Glass Fiber Post

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of bovine Herpesvirus Type 5 on development of in vitro-produced bovine embryos

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

Meio de cultura e tipo de explante no estabelecimento in vitro de espécies de maracujazeiro

Brazil is one of the main centers of genetic variability dispersion of the Passiflora genera. Its self incompatibility as well as disease incidence in its leaves and root system and, deforestation and monocultivation, promote loss of genetic material. Considering the risk of genetic erosion, the conservation of the variability in germplasm banks, which is of great interest in plant breeding, is necessary. Studies regarding the type of expiant and concentration of the culture media are necessary in order to determine protocols of establishment and in vitro conservation of passion-fruit germplasm. The objective of the present work was to evaluate the influence of the salt and nutrient concentration in the MS culture medium and types of expiants in the establishment and growth of the Passion fruit species: Passiflora giberti N. E.Brown, P. edulis Sims and P. laurifolia L. Each Passiflora species presented its own characteristics regarding in vitro development. The complete MS medium and nodal segments the second axilliary bud promoted better development of the genotypes studied.

In vitro antimicrobial activity of acroseal, polifl and epiphany against Enterococcus faecalis

Using the agar diffusion method, this study evaluated the in vitro antimicrobial activity of the commercial endodontic sealers Acroseal and Epiphany, a castor-oil based experimental sealer, Polifl, and a primer agent (Epiphany self-etching primer), against Enterococcus faecalis. Zinc oxide and eugenol cement (ZOE) served as control. Five wells per dish were made at equidistant points and immediately flled with the test and control materials. After incubation of the dishes at 37°C for 24 h and 48 h, the diameter of the zones of microbial growth inhibition produced around the wells was measured (in mm) with a millimeter rule. After 48 h, the diameters of the zones of microbial growth inhibition were the same as those observed at 24 h, only the substances continued to diffuse. Epiphany and Polifl did not show antibacterial activity (no formation of zones of microbial growth inhibition). The primer produced the largest zones of inhibition (17.62 mm) followed by Acroseal (7.25 mm) and ZOE (7.12 mm). E. faecalis was resistant to Epiphany and Polifl, while the primer and Acroseal sealer were effective against this microorganism under the tested conditions.

In vitro analysis with human bone marrow stem cells on Ti-15Mo alloy for dental and orthopedic implants application

Aim: Nowadays, research on orthopedic and dental implants is focused on titanium alloys for their mechanical properties and corrosion resistance in the human body environment. Another important aspect to be investigated is their surface topography, which is very important to osseointegration. With laser beam irradiation for roughening the implants surface an easier control of the microtopography is achieved, and surface contamination is avoided. The aim of this study was to assess human bone marrow stem cells response to a newly developed titanium alloy, Ti-15Mo, with surface topography modified by laser beam irradiation. Materials and methods: A total of 10 Ti machined disks (control), 10 Ti-15Mo machined disks and 10 Ti-15Mo disks treated by laser beam-irradiation were prepared. To study how Ti-15Mo surface topografy can induce osteoblast differentiation in mesenchymal stem cells, the expression levels of bone related genes and mesenchymal stem cells marker were analyzed, using real time Reverse Transcription-Polymerase Chain Reaction. Results: In Test 1 (comparison between Ti-15Mo machined disks and Ti-machined disks) quantitative real-time RT-PCR showed a significant induction of ALPL, FOSL1 and SPP1, which increase 20% or more. In Test 2 (comparison between Ti-15Mo laser treated disks and Ti-machined disks) all investigated genes were up-regulated. By comparing Test 1 and Test 2 it was detected that COL1A1, COL3A1, FOSL1 and ENG sensibly increased their expression whereas RUNX2, ALPL and SPP1 expression remained substantially unchanged. Conclusion: The present study demonstrated that laser treated Ti-15Mo alloys are promising materials for implants application.

Progesterone-based strategies to induce ovulation in prepubertal Nellore heifers

Four experiments were conducted to evaluate hormonal strategies to induce ovulation in Nellore heifers. In experiment 1, heifers (N = 1039) received a controlled internal drug release (CIDR) of fourth use (CIDR-4) on Day -12 or no CIDR (CIDR-0). The CIDR was removed on Day 0 in the CIDR-4 treatment, and estrus detection and AI were performed from Days 1 to 7. On Day 8, heifers not detected in estrus were evaluated for CL presence and received the same treatment again, followed by estrus detection and AI from Days 21 to 27. All heifers in experiments 2 (N = 896), 3 (N = 839), and 4 (N = 948) received the CIDR-4 treatment on Day -12. In experiment 2, heifers were randomly assigned to a control group (no additional treatment) or to receive equine chorionic gonadotropin (eCG; 200 IU eCG im) on Day 0. In experiment 3, heifers received the same treatments as in experiment 2, or a treatment that included eCG and estradiol cypionate (ECP) (eCG+ECP; 200 IU im eCG plus 0.5 mg ECP im) on Day 0. In experiment 4, heifers received the treatments described in experiment 3 or only ECP (0.5 mg) on Day 0. In experiments 2 and 3, estrus detection and AI was performed from Days 1 to 7 and on Day 8, heifers not detected in estrus were evaluated for CL presence. In experiment 4, heifers were evaluated for presence of a CL between Days 10 and 14. In experiment 1 heifers treated with CIDR-4 had greater estrus detection, ovulation induction, and pregnancy rates than in the CIDR-0 group. In experiment 2, heifers treated with eCG had greater estrus detection, ovulation induction, and pregnancy rates in 7 days than heifers in the control group. In experiment 3, heifers treated with eCG+ECP had greater estrus detection, ovulation induction, and pregnancy rates than the control and eCG treatments. In experiment 4, ovulation induction was greater for heifers treated with eCG and eCG+ECP relative to control, but did not differ from the ECP treatment. In conclusion, the use of a CIDR of fourth use for 12 days and the addition of eCG and/or ECP at CIDR removal efficiently induced ovulation and increased pregnancy rates in prepubertal Nellore heifers. © 2013 Elsevier Inc.

Effects of heat stress on development, quality and survival of Bos indicus and Bos taurus embryos produced in vitro

Heat stress is an important cause of poor development and low survival rates in bovine embryos. Experiments were conducted to test the hypothesis that Bos indicus embryos are more resistant to heat stress than are Bos taurus embryos. In experiment 1, Nelore and Jersey embryos from oocyte pick-up-derived oocytes were submitted to heat stress (96 hours post-insemination, 41 °C, 6 hours), developmental ratios were assessed at Day 7 (Day 0 = day of fertilization), and blastocysts were frozen for RNA extraction. Experiment 2 evaluated expression of COX2, CDX2, HSF1, and PLAC8 in previously frozen blastocysts. In experiment 3, Nellore and Angus embryos from oocyte pick-up-derived oocytes were submitted to heat stress (96 hours post-insemination, 41 °C, 12 hours) and transferred to recipients on Day 7. In experiment 4, embryos developed as in experiment 3 were fixed for Terminal deoxynucleotidyl transferase dUTP nick end labeling labeling and total cell counting. In experiment 1, heat stress decreased the percentage of Jersey oocytes that became blastocysts, but had no effect on Nellore embryos (34.6%, 25.0%, 39.5%, and 33.0% for Jersey control, Jersey heat-stressed, Nellore control, and Nellore heat-stressed oocytes, respectively; P < 0.05). In experiment 2, heat stress decreased (P < 0.05) expression of CDX2 and PLAC8, with higher expression of these genes in Nellore embryos than in Jersey embryos. Heat stress also decreased (P < 0.05) expression of COX2 in Jersey embryos, but had no effect on Nellore embryos. Expression of HSF1 was decreased (P < 0.05) by heat stress in both breeds, with a greater effect in Nellore embryos. In experiment 3, heat stress tended (P = 0.1) to decrease the percentage of pregnancies among cows (Day 30 to 35) that received Angus embryos. In experiment 4, heat stress increased (P < 0.05) the percentage of apoptotic blastomeres, but had no breed-specific effects. In addition, Nellore embryos had fewer (P < 0.05) Terminal deoxynucleotidyl transferase dUTP nick end labeling- positive blastomeres than did Angus embryos. We concluded that the detrimental effects of heat stress were dependent upon embryo breed and were more evident in Bos taurus embryos than in Bos indicus embryos. © 2013 Elsevier Inc.

Supplementation with the histone deacetylase inhibitor trichostatin A during in vitro culture of bovine embryos

Summary Trichostatin A (TSA) is a histone deacetylase inhibitor that induces histone hyperacetylation and increases gene expression levels. The aim of the present study was to establish a suitable condition for the use of TSA in in vitro cultures of bovine embryos, and to determine whether TSA would increase blastocyst rates by improvement of chromatin remodelling during embryonic genome activation and by increasing the expression of crucial genes during early development. To test this hypothesis, 8-cell embryos were exposed to four concentrations of TSA for different periods of time to establish adequate protocols. In a second experiment, three experimental groups were selected for the evaluation of embryo quality based on the following parameters: apoptosis, total cell number and blastocyst hatching. TSA promoted embryonic arrest and degeneration at concentrations of 15, 25 and 50 nM. All treated groups presented lower blastocyst rates. Exposure of embryos to 5 nM for 144 h and to 15 nM for 48 h decreased blastocyst hatching. However, the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay (TUNEL) assay revealed similar apoptosis rates and total cell numbers in all groups studied. Although, in the present study, TSA treatment did not improve the parameters studied, the results provided background information on TSA supplementation during in vitro culture of bovine embryos and showed that embryo quality was apparently not affected, despite a decrease in blastocyst rate after exposure to TSA. © Cambridge University Press 2011.

In vitro targeting of Polo-like kinase 1 in bladder carcinoma: Comparative effects of four potent inhibitors

Despite the improvements in neoadjuvant chemotherapy, the outcome of patients with advanced bladder cancer has changed very little over the past 30 years. In the present study we tested and compared the in vitro antitumor activities of four different inhibitors of Polo-like kinase 1 (PLK1) (BI 2536, BI 6727, GW843682X, and GSK461364), against 3 bladder carcinoma cell lines RT4, 5637 and T24. The impact on radiosensitivity and drug interactions in simultaneous treatments with cisplatin, methotrexate, and doxorubicin were also investigated. Our results showed that PLK1 inhibition prevented cell proliferation and clonogenicity, causing significant inhibition of invasion of tumor cells, though modest differences were observed between drugs. Moreover, all PLK1 inhibitors induced G2/M arrest, with the subsequent induction of death in all 3 cell lines. Drug interactions studies showed auspicious results for all PLK1 inhibitors when combined with the commonly used cisplatin and methotrexate, though combinations with doxorubicin showed mostly antagonistic effects. Comparably, the four PLK1 inhibitors efficiently sensitized cells to ionizing radiation. Our findings demonstrate that irrespective of the inhibitor used, the pharmacological inhibition of PLK1 constrains bladder cancer growth and dissemination, providing new opportunities for future therapeutic intervention. However, further laboratorial and preclinical tests are still needed to corroborate the usefulness of using them in combination with other commonly used chemotherapeutic drugs. © 2013 Landes Bioscience.

Growth regulators for in vitro propagation of Tillandsia gardneri (Bromeliaceae)

Tillandsia gardneri Lindi, is a herbaceous perennial with ornamental value. However, in Brazil there is no report about this species' cultivation on a commercial scale. The low multiplication rate of T. gardneri (in average one offshoot/plant/year) leads to illegal over-collection in the wild to meet commercial demands. The development of protocols for in vitro propagation of T. gardneri may be useful for increasing multiplication rate, producing enough plants to supply the ornamental market and also to reduce the pressure over plants collection in the wild. The present study evaluated the effect of growth regulators (6-benzylaminopurine-BA alone or in combinations with naphthaleneacetic acid-NAA) on shoots development from seedlings pre-established in vitro, from seed germination on 1/4 MS medium without growth regulators. Seedlings (with about 1.0 cm long) were re-cultured to solid 1/2 MS media supplemented with growth regulators. After 30 days on the induction medium seedlings were re-cultured to MS basal medium. The experiment was conducted in a complete randomized design with four replications and ten treatments: control (free of growth regulators), BA (0.5, 1.0 and 2.0 mg/L), BA (0.5 mg/L) + ANA (0.1 mg/L), BA (1.0 mg/L) + ANA (0.1 mg/L), BA (1.0 mg/L) + ANA (0.5 mg/L), BA (2.0 mg/L) + ANA (0.1 mg/L), BA (2.0 mg/L) + ANA (0.5 mg/L), and BA (2.0 mg/L) + ANA (1.0 mg/L). The outgrowth of shoots did not occur on medium devoid of growth regulators (control). Regression analysis for some evaluated parameters, such as percentage of seedlings responsive to shoot formation and number of shoots/seedling, and regulators concentrations (BA or ANA) were significant, allowing the establishment of the growth regulators concentration for obtaining the best multiplication rate. Some seedlings maintained in media with ANA (0.5 or 1.0 mg/L) were completely converted into callus masses that turned dark brown leading to seedlings death.

Uso do sistema de cultivo bidimensional e tridimensional para diferenciação de células-tronco espermatogoniais e indução da espermatogênese in vitro em murinos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resistência adesiva de sistemas autocondicionante e convencional frente a diferentes substratos e associação ao laser Nd:YAG: estudo in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da smear layer e da condição de tratamento da dentina (in vivo e in vitro), sobre a resistência de união

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)