Avaliação da embebição e do desenvolvimento inicial das estruturas embrionárias de sementes de milho submetidas a diferentes potenciais hídricos

Substrates with water potentials between O and -12atm, were used to evaluate the behavior of corn seeds during the germination process. Water deficiency treatments were compared with the control (adequate available water) using seeds with and without fungicide treatment. The analysis and the interpretation of the results permitted to conclude that the absorption of water, the emergency and the initial development of the embryonic structures are interdependent and vary with the water deficit. For these cases the reduction of water potential promotes difficulties in the evolution of the processes. The presence of fungicide treatment may not influence quantitatively the processes occurring in the beginning of the germination.Empregando substratos com potenciais hídricos variáveis entre 0 e -12atm, o presente trabalho objetivou avaliar o comportamento das sementes de milho postas a germinar. As situações de deficiência hídrica foram diretamente comparadas à testemunha (plena disponibilidade de água), usando sementes com e sem tratamento fungicida. A análise e a interpretação dos resultados permitiram concluir que a absorção de água, a emergência e o desenvolvimento inicial das estruturas embrionárias são interdependentes e reagem no mesmo sentido ao déficit hídrico; para esses casos, a redução do potencial hídrico promove dificuldades na evolução dos processos. Paralelamente, a presença de tratamento fungicida pode não influenciar, quantitativamente, os fenômenos envolvidos no início da germinação

Follow-up of patients treated with retinoic acid for the control of radioiodine non-responsive advanced thyroid carcinoma

During thyroid tumor progression, cellular de-differentiation may occur and it is commonly accompanied by metastatic spread and loss of iodine uptake. Retinoic acid (RA) administration might increase iodine uptake in about 40% of patients, suggesting that RA could be a promising therapeutic option for radioiodine non-responsive thyroid carcinoma, although a prospective study with a long-term follow-up has not been reported. This was a clinical prospective study assessing the value of 13-cis-RA in patients with advanced thyroid carcinoma and its impact on major outcomes such as tumor regression and cancer-related death with a long-term follow-up of patients submitted to radioiodine (131I) therapy after RA administration. Sixteen patients with inoperable disease and no significant radioiodine uptake on post-therapy scan were selected. Patients were treated orally with 13-cis-RA at a dose of 1.0 to 1.5 mg·kg-1·day-1 for 5 weeks and then submitted to radioiodine therapy (150 mCi) after thyroxine withdrawal. A whole body scan was obtained 5 to 7 days after the radioactive iodine therapy. RECIST criteria were used to evaluate the response. An objective partial response rate was observed in 18.8%, a stable disease rate in 25% and a progression disease rate in 56.2%. Five patients died (62.5%) in the group classified as progression of disease. Progression-free survival rate (PFS) ranged from 72 to 12 months, with a median PFS of 26.5 months. RA may be an option for advanced de-differentiated thyroid cancer, due to the low rate of side effects

Microleakage of an adhesive system used as a fissure sealant

Aim: The aim of this study was to investigate the microleakage of pit and fissure sealants in primary teeth and to determine if multi-step methods should produce better results in terms of microleakage prevention. Methods and materials: A total of 40 intact primary molars were randomly assigned to one of four sealant groups: resin based sealant Ultraseal XT (US - Ultradent) (Group 1, n=10); adhesive system Scotchbond Multi Purpose Plus (SBMP - 3M/ESPE) used as a sealant (Group 2, n=10); primer (SBMP) and US (Group 3, n=10); and primer, bond (SBMP) and US (Group 4, n=10). After thermocycling (x700, 5-55 degrees C) all teeth surfaces were made impermeable with the exception of the occlusal surface. Samples were immersed in 50% silver nitrate for 8 hours, sectioned longitudinally with two cuts in the central fissure pit, and then immersed in photo development solution followed by 16 hours in fluorescent light. Pictures were obtained by light microscope (x40) and the degree of microleakage was evaluated by three blinded evaluators. The data were analyzed using the Kruskal Wallis test. Results: Significant statistical differences (p<.05) were observed between Groups 1-3, Groups 2-3, Groups 2-4, and Groups 3-4. Group 3 showed higher microleakage scores. Conclusion: The adhesive system and the resin based sealant demonstrated similar microleakage properties, suggesting the possibility that adhesives can be used in a clinical setting. Additionally, the increase in the number of clinical steps required by common application of resin based sealant, including use of primer or primer and bond, did not lead to better results in preventing microleakage. Clinical significance: The adhesive system can be used as a sealant without increasing the microleakage. Thus, the use of the adhesive system before the application of the sealant is not necessary to reduce the microleakage, although further research is warranted to support this conclusion