ENDOCRINOLOGIA REPRODUTIVA E CONTROLE DA FERTILIDADE DA CADELA - REVISÃO

O aparelho reprodutor da cadela está sujeito a alterações periódicas que estão diretamente relacionadas ao ciclo estral. Estabelecer critérios para a identificação desses estádios, e do período de maior fertilidade da fêmea, é essencial para se determinar o momento ideal para cobertura natural ou inseminação artificial. Nos últimos anos métodos de prevenção ou interrupção da gestação têm sido descritos visando o controle populacional de cães e gatos. As medidas de controle incluem cirurgia, terapia hormonal e, mais recentemente, controle imunológico. A ovariohisterectomia é provavelmente o método de contracepção mais adequado para animais não destinados à reprodução. Nos casos que envolvem a terapia hormonal como método contraceptivo, a precaução na utilização do medicamento no período mais adequado do ciclo é importante para a diminuição do surgimento de afecções uterinas e da glândula mamária. Diante destas observações essa revisão tem como objetivo abordar aspectos relacionados à fisiologia e endocrinologia reprodutiva na cadela, enfatizando o controle reprodutivo e seus efeitos colaterais. Reproductive endocrinology and fertility control in bitches a review Abstract Bitch reproductive organs of undergo periodical changes during the stages of the estrous cycle. The establishment of features of each stage of the estrous cycle, and the period of female higher fertility, is important for the determination of the optimal days for mating or artificial insemination. In the last decade methods of prevention or termination of pregnancy have been proposed for population growth control of dogs and cats This includes surgery, hormonal therapy and, more recently, immunological control. Ovaryhysterectomy is probably the best method of contraception for bitches not intended for breeding. In cases where hormones are used as a method for contraception, it is important to know the precise stages of the cycle to avoid possible side effects, like uterine or mammary gland diseases. The main concerns of the present review are the reproductive physiology and endocrinology of the bitch and the methods for contraception and possible side effects induced by such procedure

Influence Of Polymeric Additives On The Mechanical Properties Of α-tricalcium Phosphate Cement

Recently, great attention has been paid to calcium phosphate cements, because of their advantages in comparison with conventional calcium phosphate bioceramics employed for bone repairing, regarding in situ handling, and shaping abilities. Nevertheless, the calcium phosphate cements exhibit relatively low mechanical strength. The aim of this work was the improvement of the compressive strength of α-tricalcium phosphate-based cement. The hydraulic setting reaction of this system produces a calcium-deficient hydroxyapatite phase suitable for bone repairing: α-Ca3(PO4)2 + H2O → Ca9(HPO4)(PO4)5OH. Mechanical strength can be improved using technological solutions developed for other applications, such as Portland cement and dual-setting glass-ionomers, by using polymeric additives. The additives used in this work were sodium alginate, sodium polyacrylate, and an in situ polymerization system resulting in a polyacrylamide crosslinked hydrogel. Parameters evaluated were setting time, compressive strength before and after immersion in simulated body fluid, density, porosity, crystalline phases, and microstructure. Sodium alginate and sodium polyacrylate were deleterious to both setting time and mechanical strength. When the in situ polymerization system was added, two setting reactions progressed in parallel: the conventional hydraulic reaction and the copolymerization of acrylamide and crosslinking water-soluble monomers. The initial and final setting times of the 'dual-setting' cement were 9 and 35 min, respectively, and they can be regulated varying the initiator, catalyst, and monomers concentrations. The initial compressive strength of the dual- setting cement (6.8 MPa at 0 h, and 15.2 MPa at 24 h) is higher than that of unmodified cement. The major crystalline phase after setting is hydroxyapatite. The dual-setting cement seems to be suitable for clinical applications in bone repairing and remodeling. Copyright (C) 1999 Elsevier Science Inc.25SUPPL. 199S102SStandard Test Method for Time of Setting of Hydraulic-cement Paste by Gillmore NeedlesCarrodeguas, R.G., De Oliveira, L.C., Dos Santos, L.A., Rigo, E.C.S., Boschi, A.O., Mondéjar, S.P., Effect of Polymeric Additions on the Properties of Calcium Salts Cements, , Rev CNIC Ciencias Químicas (Cuba) (In press)Driessens, F.C.M., Fernández, E., Ginebra, M.P., Boltong, M.G., Planell, J.A., Calcium phosphates and ceramic bone cements vs. acrylic cements (1997) Anal Quim Int Ed, 93 (SUPPL.), pp. 38-43Ginebra, M.P., Boltong, M.G., Fernández, E., Planell, J.A., Driessens, F.C.M., Effect of various additives and temperature on some properties of an apatitic calcium phosphate cement (1995) J Mater Sci Mater Med, 6, pp. 612-616Ginebra, M.P., Fernández, E., De Maeyer, E.A.P., Setting reaction and hardening of an apatitic calcium phosphate cement (1997) J Dent Res, 76, pp. 905-912Kokubo, T., Kushitani, H., Ohtsuki, C., Sakka, S., Yamamuro, T., Chemical reaction of bioactive glass and glass ceramics with a simulated body fluid (1992) J Mater Sci Mater Med, 3, pp. 79-83McLean, J.W., Nicholson, J.W., Wilson, A.D., Proposed nomenclature for glass ionomer dental cements and related materials (1994) Quintessence Int, 25, pp. 587-589Miyazaki, K., Horibe, T., Anntonucci, J.M., Takagi, S., Chow, L.C., Polymeric calcium phosphate cements: Analysis of reaction products and properties (1993) Dent Mater, 9, pp. 41-45Miyazaki, K., Horibe, T., Anntonucci, J.M., Takagi, S., Chow, L.C., Polymeric calcium phosphate cements: Setting reaction modifiers (1993) Dent Mater, 9, pp. 46-49Silver, F., Doillon, C., Biocompatibility (1989) Interactions of Biological and Implantable Materials. Vol. 1. Polymers, 1. , New York: VCH PublishersYoung, A.C., Omatete, O.O., Janney, M.A., Menchhoffer, P.A., Gel-casting of alumina (1991) J Am Ceram Soc, 74, pp. 612-61