RESUMO
OBJECTIVES: to assess the effectiveness of Distal Jet without simultaneous fixed appliance treatment. SUBJECTS AND METHODS: twenty subjects with Class II malocclusion who received the Distal Jet appliance to move maxillary molars distally. Subsequently, the canine and premolar distal movements were achieved by the use of.017 x.025 Ni-Ti sectional wires and memory power chain. RESULTS: revealed that Distal Jet is more effective with less anchorage loss when this appliance is used independent of multibracket appliances. CONCLUSION: this study showed that Distal Jet is an effective and predictable appliance. The distal movements of upper premolars, canines and incisors with sectional wires fabricated from.017 x.025 Ni-Ti were biomechanically very effective, simple in clinical application, and did not require any patient compliance.
Assuntos
Dente Pré-Molar/patologia , Dente Canino/patologia , Má Oclusão Classe II de Angle/terapia , Dente Molar/patologia , Desenho de Aparelho Ortodôntico , Técnicas de Movimentação Dentária/instrumentação , Adolescente , Cefalometria , Criança , Ligas Dentárias , Feminino , Humanos , Masculino , Maxila , Níquel , Fios Ortodônticos , Estresse Mecânico , TitânioAssuntos
Hemodinâmica/fisiologia , Fator de Crescimento Insulin-Like I/farmacologia , Transplante de Rim/fisiologia , Análise de Variância , Animais , Pressão Sanguínea , Nitrogênio da Ureia Sanguínea , Temperatura Corporal , Creatinina/sangue , Feminino , Frequência Cardíaca , Hemodinâmica/efeitos dos fármacos , Humanos , Período Intraoperatório , Consumo de Oxigênio , Período Pós-Operatório , Proteínas Recombinantes/farmacologia , Suínos , Transplante Autólogo , Resistência VascularRESUMO
The inhibitory effect of triiodothyronine (T3) given in early postnatal life on Sertoli cell proliferative activity, leading to their precocious terminal differentiation, has been demonstrated previously. However, data concerning the role of thyroid hormone on androgen metabolism of Sertoli cells during the same period are still lacking. In this study we performed a time-course investigation on the effects of T3 treatment on testosterone metabolism in Sertoli cells isolated from 2-, 3- and 4-weeks-old euthyroid rats. Triiodothyronine (3 micrograms/100 g body wt) was given ip., during the last week prior to sacrifice. Sertoli cells from all animal groups initially were cultured under basal conditions during the first 24 h and subsequently in the presence of testosterone (0.5 mumol/l) with or without T3 (1 nmol/l) for an additional 24 h. This treatment given to 2-week-old animals resulted in reduced testicular growth. As far as androgen metabolism is concerned, T3 in vivo and in vitro treatment in 2- and 3-week-old animals induced a lowering of dihydrotestosterone + 3 alpha-diol with an enhancement of the two other 5 alpha-reduced androgens. The effect was much less pronounced in the oldest group. In both 2- and 3-week-old treated rats a marked reduction of oestradiol was observed, which indicates an inhibition of aromatase activity, mainly in younger animals. This enzyme has been reported to be extremely active in Sertoli cells of rats (of the same strain) between the age of 5 and 20 days, but it decreases rapidly thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Células de Sertoli/metabolismo , Testosterona/metabolismo , Tri-Iodotironina/farmacologia , Fatores Etários , Animais , Peso Corporal , Células Cultivadas , Meios de Cultura/metabolismo , Seguimentos , Masculino , Ratos , Ratos Wistar , Testículo/crescimento & desenvolvimento , Testículo/metabolismoRESUMO
The aim of the present study was to investigate the influence of thyroid hormones on androgen metabolism in Sertoli cells isolated from 3- and 4- week-old rats. Hypothyroidism was induced by the oral administration of 0.025% methimazole (MMI) from birth until the rats were killed at 3 and 4 weeks of age. Half of the MMI-treated animals were injected i.p. with L-triiodothyronine (T3 3 micrograms/100 g body weight) during the last week before death. Sertoli cells from all groups were initially cultured under basal conditions for the first 24 h and subsequently in the presence of testosterone with or without T3 for an additional 24 h. Hypothyroidism was associated with severe impairment of body as well as testicular growth. Indeed, body and testicular weights were similar in 4-week-old hypothyroid animals to those in 3-week-old control rats. Testosterone metabolism in Sertoli cells isolated from 3- and 4-week-old hypothyroid rats was mainly expressed by the lowering of 5 alpha-dihydrotestosterone + androstane 3 alpha, 17 beta-diol and an enhanced formation of 5 alpha-reduced steroids with poor androgenic properties (e.g. 5 alpha-androstane, 3, 17 alpha-dione (androstanedione), 5 alpha-androstane, 3-ol-17-one (androsterone)). Treatment of the same group of animals with T3 in vivo and in vitro did not influence the pattern of 5 alpha-reductase steroids substantially. The most striking finding in the Sertoli cells of 3-week-old hypothyroid rats was the dramatic enhancement of oestradiol formation which persisted to a lesser extent 1 week later.(ABSTRACT TRUNCATED AT 250 WORDS)
