RESUMEN
The effect of lengthening on muscle metabolism was measured and correlated to the percent lengthening at early and late time points. Using the rabbit tibial lengthening model, the authors examined the effects of lengthening on the tibialis anterior muscle using phosphorus-31 magnetic resonance spectroscopy. Thirty-six rabbits were divided into five groups, four groups by percent lengthening (0%, 15%, 20%, and 25%), with each group divided into subgroups of early (end distraction) and late (12 weeks after end distraction), and the fifth group using the opposite untreated leg as control. Several parameters measuring metabolism of muscle using phosphorus-31 magnetic resonance spectroscopy analysis were compared. No changes occurred to 15% lengthening, but significant decreases were measured at 20% and 25% lengthening. After a 25% lengthening, the decreased metabolism persisted at 12 weeks after distraction, indicating the possibility of permanent damage. After 20% lengthening, the same parameters improved but never to normal levels. The authors conclude that lengthening to 15% is safe for muscle, but 20% to 25% lengthening may result in permanent metabolic damage. The current study also suggests that phosphorus-31 magnetic resonance spectroscopy may provide a viable clinical method for evaluating muscle damage during lengthening.
Asunto(s)
Alargamiento Óseo , Metabolismo Energético , Músculo Esquelético/metabolismo , Tibia/cirugía , Adenosina Trifosfato/metabolismo , Animales , Alargamiento Óseo/instrumentación , Alargamiento Óseo/métodos , Tornillos Óseos , Fijadores Externos , Espectroscopía de Resonancia Magnética , Fosfatos/metabolismo , Fosfocreatina/metabolismo , Conejos , Factores de TiempoRESUMEN
The isolation and structure elucidation of five novel natural Diels--Alder-type adducts, named palodesangrens A-E (1-5), from the Peruvian folk medicine known as "palo de sangre" (Brosimum rubescens) is described. The structures of the Diels--Alder adducts, consisting of chalcone derivatives and a prenylcoumarin, were elucidated by analysis of spectroscopic data including 2D NMR. Some of these compounds showed potent inhibitory activity towards 5 alpha-dihydrotestosterone (DHT) binding with an androgen receptor to form a DHT-receptor complex that causes androgen-dependent diseases.
Asunto(s)
Antagonistas de Andrógenos/aislamiento & purificación , Chalcona/aislamiento & purificación , Cumarinas/aislamiento & purificación , Plantas Medicinales/química , Inhibidores de 5-alfa-Reductasa , Antagonistas de Andrógenos/química , Antagonistas de Andrógenos/farmacología , Antagonistas de Receptores Androgénicos , Animales , Chalcona/análogos & derivados , Chalcona/química , Chalcona/farmacología , Cromatografía Líquida de Alta Presión , Cumarinas/química , Cumarinas/farmacología , Técnicas In Vitro , Espectroscopía de Resonancia Magnética , Masculino , Perú , Epidermis de la Planta/química , Ratas , Ratas Wistar , Espectrometría de Masa Bombardeada por Átomos VelocesRESUMEN
Four new compounds, 9-hydroxy-6,7-dimethoxydalbergiquinol, 6-hydroxy-2,7-dimethoxyneoflavene, 6,4'-dihydroxy-7-methoxyflavan and 2,2',5-trihydroxy-4-methoxybenzophenone, in addition to eight known phenolic compounds including 7-hydroxy-6-methoxyflavone, have been isolated from the stems of Dalbergia cochinchinensis. Their structures were established by spectroscopic techniques including one- and two-dimensional NMR methods. The first two compounds showed potent inhibitory activity towards 5 alpha-dihydrotestosterone (DHT) which binds with an androgen receptor to form a DHT-receptor complex that causes androgen-dependent disease.