Myostatin inhibition: a potential performance enhancement strategy?

A decade has passed since myostatin was first identified as a negative regulator of muscle growth. Since then, studies in both humans and animals have demonstrated that decreasing the levels of this growth factor or inhibiting its function can dramatically increase muscle size, and a number of therapeutic applications of myostatin inhibition to the treatment of myopathies and muscle atrophy have been proposed. As such treatments would be likely to also stimulate muscle growth in healthy individuals, there is a growing concern among anti-doping authorities that myostatin inhibitors may be among the next generation of ergogenic pharmaceuticals or even in the vanguard of "gene doping" technology. While the ability to stimulate muscle growth through myostatin inhibition is well documented, a growing body of evidence suggests such increases may not translate into an improvement in athletic performance. This article briefly reviews the function of this potent regulator of muscle development and explores the potential therapeutic uses, and potential ergogenic abuses, of myostatin manipulation.     

新型超声导管体外消融血栓

目的探讨新型超声导管体外消融血栓的可行性和疗效。方法体外制备人全血细胞血栓54份并分成三组,应用传统球型（Ⅰ型）和新的球部顶端平截面型（Ⅱ型）及前方带缺口球型（Ⅲ型）三种不同头端的低频高能超声导管,体外对全血细胞血栓块行超声消融60s,比较消融前后固体血栓称重及融栓后上清液血栓碎片和红细胞直径。结果不同头端超声导管均可明显消融血栓,消融前后固体血栓称重差异比有显著意义（P〈0．01）,Ⅲ型和Ⅰ型组明显优于Ⅱ型组（P〈0．05）;显微镜下90％血栓碎片直径小于红细胞。结论体外低频高能超声可消融血栓,头端形状对血栓超声消融能力有明显的影响。     

Anterograde TNFα Transport From Rat Dorsal Root Ganglion To Spinal Cord And Injured Sciatic Nerve

Spontaneous activity originating in the injured nerve or the dorsal root ganglion (DRG) has been implicated in the development and maintenance of neuropathic pain. The inherent characteristics of spontaneous activity and the causal factors that modulate its firing pattern and frequency are not fully understood. We attempted to assess the thermosensitivity of spontaneous activity in dorsal root ganglion (DRG) neurons in normal rats and in rat, with cl-ironic compression of the DRG (CCD) in an in vitro nerve-DRG preparation. Extracellular, dorsal root recording from 66 spontaneously active CCD Abeta fibers indicate that: (1) decreasing bath temperature from 37 to 36-26 °C significantly decreased the firing rate (FR) in 85% (56/66) of fibers tested, of which 19 fibers (34%) responded to temperature change at physiological range (36-37 °C), whereas the remaining fibers responded at lower temperature levels (26-36 °C); (2) cooling of the DRG increased the FR in 12% (8/66) of fibers tested; (3) similarly, the firing rate of 21/26 spontaneously active Abeta fibers from normal rats was decreased following temperature decrease; (4) intracellular recordings from 38 normal neurons revealed that cooling the DRG significantly increased the action potential (AP) threshold, A-P duration, AP amplitude and afterhyperpolarization (AHP) duration, but decreased AHP amplitude, maximal depolarizing and repolarizing rates. There was no significant change in the rheobase currents or the resting membrane potential. The present study indicates that large sensory neurons with myelinated axons are temperature dependent. It also suggests that maintenance of a stable temperature is critical for reliable characterization of spontaneous activity of sensory neurons.