A randomized, double-masked, multicenter comparison of the safety of continuous intrathecal labor analgesia using a 28-gauge catheter versus continuous epidural labor analgesia.

BACKGROUND: Continuous intrathecal labor analgesia produces rapid analgesia or anesthesia and allows substantial flexibility in medication choice. The US Food and Drug Administration, in 1992, removed intrathecal microcatheters (27-32 gauge) from clinical use after reports of neurologic injury in nonobstetric patients. This study examined the safety and efficacy of a 28-gauge intrathecal catheter for labor analgesia in a prospective, randomized, multicenter trial. METHODS: Laboring patients were randomly assigned to continuous intrathecal analgesia with a 28-gauge catheter (n = 329) or continuous epidural analgesia with a 20-gauge catheter (n = 100), using bupivacaine and sufentanil. The primary outcome was the incidence of neurologic complications, as determined by masked neurologic examinations at 24 and 48 h postpartum, plus telephone follow-up at 7-10 and 30 days after delivery. The secondary outcomes included adequacy of labor analgesia, maternal satisfaction, and neonatal status. RESULTS: No patient had a permanent neurologic change. The continuous intrathecal analgesia patients had better early analgesia, less motor blockade, more pruritus, and higher maternal satisfaction with pain relief at 24 h postpartum. The intrathecal catheter was significantly more difficult to remove. There were no significant differences between the two groups in neonatal status, post-dural puncture headache, hemodynamic stability, or obstetric outcomes. CONCLUSIONS: Providing intrathecal labor analgesia with sufentanil and bupivacaine via a 28-gauge catheter has an incidence of neurologic complication less than 1%, and produces better initial pain relief and higher maternal satisfaction, but is associated with more technical difficulties and catheter failures compared with epidural analgesia.

Synapsin and synaptic vesicle protein expression during embryonic and post-natal lens fiber cell differentiation.

PURPOSE: Reorganization of cytoskeleton and membrane biogenesis are dynamically coordinated during lens fiber cell differentiation and development to produce an organ with precise dimensions and optical properties. Cargo vesicle trafficking is fundamental to cell elongation and has also been implicated in degenerative disease mechanisms. Alzheimer precursor protein (AbetaPP) acts with kinesin, synapsin, and synaptic vesicle proteins to mediate cargo vesicle transport and membrane fusion in neurons. In our previous studies we demonstrated that AbetaPP is also a key element in lens fiber cell formation, and in early-onset cataract that occurs along with early-onset Alzheimer disease in Down syndrome. In the present study we examine lens expression and regulation of a complement of genes associated with cargo and synaptic vesicle transport in neurons. METHODS: RT-PCR, immunoblot, and immunohistochemical methods were used to characterize expression of AbetaPP and kinesin associated motor proteins, synapsins, and synaptic vesicle proteins in mouse and rat embryonic, post-natal, and adult lenses. Phospho-specific anti-synapsin antibodies were used to determine the distributions of site-1 phosphorylated and dephosphorylated synapsin protein. RESULTS: We demonstrate that a substantial complement of cargo and synaptic vesicle proteins involved in AbetaPP mediated vesicle transport are expressed in lenses along the anterior-posterior axis of fiber cells in embryonic and adult lenses, consistent with vesicles, actin filaments, and neuron-like arrangement of microtubules in lenses shown by others. We identify temporal regulation of synapsins I, II, and III during embryonic and post-natal lens development consistent with their roles in neurons. Regulation of vesicle cytoskeleton attachment, actin polymerization, and the capacity to stimulate cell differentiation by synapsins are governed in large part by phosphorylation at a conserved Ser9 residue (site-1). We demonstrate discrete distributions of Ser9 phospho- and dephospho-synapsins along the axial length of rapidly elongating embryonic lens fiber cells, and decreased levels of site-1 phosphorylated synapsins in adult lenses. CONCLUSIONS: The present findings demonstrate several fundamental parallels between lens and neuron vesicle trafficking cell biology and development, and suggest that more extensive AbetaPP related vesicle trafficking disease mechanisms may be shared by lens and brain.