Bonding of Y-TZP to Dentin: Effects of Y-TZP Surface Conditioning, Resin Cement Type, and Aging

Purpose: To evaluate the effects of two surface treatments, aging, and two resin cements on shear bond strength between dentin and yttrium-stabilized tetragonal zirconia polycrystal ceramic (Y-TZP).Materials and Methods: Eighty human molars were embedded in acrylic resin and sectioned 3 mm below the occlusal plane. These teeth and 80 cylindrical Y-TZP specimens (height, 4 mm; diameter, 3.4 mm) were divided into eight groups (n=10) using the following factors: Y-TZP surface treatment (Vi: low-fusing porcelain [vitrification] + hydrofluoric acid etching + silanization or Si: tribochemical silicatization); cementation strategies (PF: Pan avia or CC: Clearfil); and storage (nonaging or aging). Bonding surfaces of 40 Y-TZP specimens received Vi treatment, and the rest received Si treatment. Half of the ceramic-tooth assemblies were cemented with Panavia, the rest with Clearfil. Shear tests were executed using 0.4-mm-thick wire at 0.5 mm/min. Data were analyzed by three-way analysis of variance and Tukey test (alpha=0.05). Fractures were analyzed.Results: Y-TZP surface treatments did not affect bond strength (p=0.762, Vi = Si), while resin cements (p<0.001, Panavia > Clearfil) and aging (p=0.006, nonaging > aging) showed a significant effect. Most failures were in adhesive at dentin-cement interfaces; no failure occurred between zirconia and cement.Conclusion: When Y-TZP ceramic is bonded to dentin, the weakest interface is that between dentin and resin cement. The resin cement/Y-TZP interface was less susceptible to failures, owing to Y-TZP surface treatments.

Efficiency of OPU-IVEP-ET of Fresh and Vitrified Embryos in Buffaloes

The present study aims to report ovum pickup (OPU), in vitro embryo production (IVEP) and embryo transfer (ET) outcomes of fresh and vitrified buffalo embryos. For this purpose, 36 buffalo donors were submitted to 11 OPU sessions (n = 201). A total of 998 oocytes (5.0 +/- 0.5/donor/session) and 584 viable oocytes (2.9 +/- 0.3/donor/session) were recovered. Viable oocytes (grades 1, 2 and 3) were subjected to IVM, IVF (D0) and IVC. On D2, 54.5% of cleavage rate was obtained. Embryo yield on D7 was 44.9% (grade 1: 229 embryos, grade 2: 5 embryos and grade 3: 28 embryos). From this total, 115 fresh (grades 1 to 3) and 70 vitrified embryos (only grade 1) were transferred into recipients previously synchronized with fixed time embryo transfer (FTET) protocol. Vitrification was performed using the cryotop method. Pregnancy diagnosis in fresh and in vitrified groups were, respectively: 43.5% (50/115) and 37.1% (26/70) on 30 days after embryo transfer, and 41.7% (48/115) and 31.4% (22/70) on 60 days after embryo transfer. In conclusion, our results demonstrate the possibilities for commercial use of the techniques of OPU, IVEP and ET of fresh and vitrified embryos in buffaloes.

Seedling Development and Evaluation of Genetic Stability of Cryopreserved Dendrobium Hybrid Mature Seeds

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In vitro conservation of Dendrobium germplasm

Dendrobium is a large genus in the family Orchidaceae that exhibits vast diversity in floral characteristics, which is of considerable importance to orchid breeders, biotechnologists and collectors. Native species have high value as a result of their medicinal properties, while their hybrids are important as ornamental commodities, either as cut flowers or potted plants and are thus veritable industrial crops. Thus, preservation of Dendrobium germplasm is valuable for species conservation, breeding programs and the floriculture industry. Cryopreservation represents the only safe, efficient and cost-effective long-term storage option to facilitate the conservation of genetic resources of plant species. This review highlights 16 years of literature related to the preservation of Dendrobium germplasm and comprises the most comprehensive assessment of thorough studies performed to date, which shows reliable and reproducible results. Air-drying, encapsulation-dehydration, encapsulation-vitrification, vitrification and droplet-vitrification are the current cryopreservation methodologies that have been used to cryopreserve Dendrobium germplasm. Mature seeds, pollen, protoplasts, shoot primordia, protocorms and somatic embryos or protocorm-like bodies (PLBs) have been cryopreserved with different levels of success. Encapsulation-vitrification and encapsulation-dehydration are the most used protocol, while PLBs represent the main explant explored.

Reduced levels of intracellular reactive oxygen species and apoptotic status are not correlated with increases in cryotolerance of bovine embryos produced in vitro in the presence of antioxidants

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

Criopreservação de embriões bovino produzidos in vitro: estado da arte

In the last years, the embryo in vitro production for every domestic species and mainly for bovine has attained a notorius status. This reproductive biotechnical procedure associate with ultrasound-guided ovum pick up (OPU) has been more and more incorporated and spread in our cattle herds, ranking up Brazil already at the top of the list in number of in vitro embryo produced. Some significant advantages provided, such as the possibility of using the premature or pregnant animals oocytes, without necessarily requiring the use of hormonal treatment, to make it possible to generate pregnancy at a shorter period of time, the rationalization in the use of semen and optimization in the use of sexed semen were determinant factors for OPU/IVP to reach this outstanding position. Nevertheless, right now the possibility of IVP embryo cryopreservation, just now is the biggest impediment for maximizing the use of this biotechnology, due to both lack of efficient methods and low laboratory produced embryo cryotolerance. Nowadays, the most used methods of IVP embryo cryopreservation are: slow freezing and vitrification. Traditionally, slow freezing is still the most used methods for in vivo and in vitro produced embryo cryopreservation. However, more recently vitrification - although still not commercially used in large scale - has been presenting satisfactory results in IVP embryo cryopreservation, according to searches

Avaliação da viabilidade e desenvolvimento in vitro de oócitos de gatas domésticas após vitrificação em meio suplementado com vitamina E

Pós-graduação em Medicina Veterinária - FCAV

Efeitos de diferentes inibidores da meiose sobre a maturação in vitro de oócitos bovinos e subsequente tolerância dos embriões a vitrificação

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

Efeitos da congelação lenta e da vitrificação na viabilidade, ultraestrutura e expressão gênica de embriões caninos produzidos in vivo

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

Criopreservação de oócitos de Prochilodus lineatus (Valenciennes, 1836) (Teleostei, Prochilodontidae)

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Membrane lipid profile monitored by mass spectrometry detected differences between fresh and vitrified in vitro-produced bovine embryos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reduction in cytoplasmic lipid content in bovine embryos cultured in vitro with linoleic acid in semi-defined medium is correlated with increases in cryotolerance

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

Estratégias para minimização do estresse oxidativo em sistemas de produção in vitro de embriões bovinos destinados à vitrificação

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

Effects of different cryopreservation methods on post-thaw culture conditions of in vitro produced bovine embryos

The aim of this work was to evaluate the effect of cryopreservation protocols on subsequent development of in vitro produced bovine embryos under different culture conditions. Expanded in vitro produced blastocysts (n = 600) harvested on days 7-9 were submitted to controlled freezing [slow freezing group: 10% ethylene glycol (EG) for 10 min and 1.2 degrees C/min cryopreservation]; quick-freezing [rapid freezing group: 10% EG for 10 min, 20% EG + 20% glycerol (Gly) for 30 s]; or vitrification [vitrification group: 10% EG for 10 min, 25% EG + 25% Gly for 30 s] protocols. Control group embryos were not exposed to cryoprotectant or cryopreservation protocols and the hatching rate was evaluated on day 12 post-insemination. In order to evaluate development, frozen-thawed embryos were subjected to granulosa cell co-culture in TCM199 or SOFaa for 4 days. Data were analyzed by PROC MIXED model using SAS Systems for Windows (R). Values were significant at p < 0.05. The hatching rate of the control group was 46.09%. In embryos cultured in TCM199, slow freezing and vitrification group hatching rates were 44.65 +/- 5.94% and 9.43 +/- 6.77%, respectively. In embryos cultured in SOFaa, slow freezing and vitrification groups showed hatching rates of 11.65 +/- 3.37 and 8.67 +/- 4.47%, respectively. In contrast, the rapid freezing group embryos did not hatch, regardless of culture medium. The slow freezing group showed higher hatching rates than other cryopreservation groups. Under such conditions, controlled freezing (1.2 degrees C/min) can be an alternative to cryopreservation of in vitro produced bovine embryos.

Post-thaw viability of in vivo-produced canine blastocysts cryopreserved by slow freezing

The objectives were to evaluate the reexpansion blastocoele rate, post-thaw viability, and in vitro development of canine blastocysts cryopreserved by slow freezing in 1.0 m glycerol (GLY) or 1.5 m ethylene glycol (EG). Fifty-one in vivo-produced canine blastocysts were randomly allocated in two groups: GLY (n = 26) and EG (n = 25). After thawing, embryos from MO were immediately stained with the fluorescent probes propidium iodide and Hoechst 33 342 to evaluate cellular viability. Frozen-thawed embryos from M3 and M6 were cultured in SOFaa medium + 10% FCS at 38.5 degrees C under an atmosphere of 5% CO2 with maximum humidity, for 3 and 6 days, respectively, and similarly stained. The blastocoele reexpansion rate (24 h after in vitro culture) did not differ between GLY (76.5%) and EG (68.8%). Post-thaw viable cells rate were not significantly different between GLY and EG (66.5 +/- 4.8 and 57.3 +/- 4.8, respectively, mean +/- SEM), or among MO (62.3 +/- 5.7%), M3 (56.9 +/- 6.0%), and M6 (66.5 +/- 6.0%). In conclusion, canine blastocysts cryopreserved by slow freezing in 1.0 m glycerol or 1.5 m ethylene glycol, had satisfactory blastocoele reexpansion rates, similar post-thawing viability, and remained viable for up to 6 days of in vitro culture. (C) 2012 Elsevier Inc. All rights reserved.