Wendy Su

Demonstration of κ3-Opioid Receptors in the SH-SY5Y Human Neuroblastoma Cell Line

Abstract: In addition to the μ‐ and δ‐opioid receptors previously reported, the SH‐SY5Y human neuroblastoma cell line has high levels of κ3 receptors, accounting for 40% of total opioid binding, as measured with [3H]‐diprenorphine binding. Competition studies reveal binding profiles for all three receptor classes that are similar to those observed in brain membranes. Differentiation with retinoic acid increases the levels of opioid receptor binding in the cell line, with the largest elevations in κ3 binding. Fully 75% of the increased binding corresponds to κ3 sites, which represent 50% of total opioid receptor binding in differentiated cells. Morphine inhibits forskolin‐stimulated cyclic AMP accumulation, and this effect is readily blocked by the μ antagonist d‐Phe‐Cys‐Tyr‐d‐Trp‐Arg‐Thr‐Pen‐Thr‐NH2 (CTAP). Naloxone benzoylhydrazone, a κ3 agonist, inhibits forskolin‐stimulated cyclic AMP accumulation more potently than morphine and is not reversed by CTAP. These studies indicate that SH‐SY5Y cells contain high levels of functional κ3 receptors.

Antisense oligodeoxynucleotides to the cloned δ receptor DOR-1 : uptake, stability, and regulation of gene expression

Abstract: Phosphodiester antisense oligodeoxynucleotides (ODNs) directed against various domains of the cloned mouse δ receptor DOR‐1 reduce δ‐opioid receptor binding in vivo and in vitro. The present study examines the stability of an antisense ODN (275 nM) directed against the δ‐opioid receptor and its effect on DOR‐1 mRNA in cultured neuroblastoma cells and in vivo. When added to NG108‐15 cells, much of the antisense ODN is degraded. However, >1% is intact, associated with cells, and stable for at least 72 h. Northern blot analysis demonstrates that treatment of NG108‐15 cells with the antisense ODN reduces the levels of a species of DOR‐1 mRNA by ∼25%. Similarly, intrathecal administration of the antisense ODN results in the accumulation of intact ODN within the spinal cord, which is stable for at least 72 h, although the levels of accumulation in vivo are lower than in vitro after either 4 or 72 h. Antisense ODN treatment lowers DOR‐1 mRNA levels by ∼25%. The loss of mRNA both in vivo and in vitro corresponds quite well to the decreases in receptor binding previously observed by our laboratory and is consistent with reduction of δ‐opioid receptor protein in vitro as determined by western blot with a monoclonal antibody selective for the δ‐opioid receptor. In conclusion, these studies indicate that a small, but significant, proportion of ODN is taken up by cells and remains intact for up to 72 h. This appears to be sufficient to down‐regulate mRNA levels of δ‐opioid receptors and their expression.

The role of multidrug resistance‐associated protein in the blood–brain barrier and opioid analgesia

The blood–brain barrier protects the brain from circulating compounds and drugs. The ATP‐binding cassette (ABC) transporter P‐glycoprotein (Pgp) is involved with the barrier, both preventing the influx of agent from the blood into the brain and facilitating the efflux of compounds from the brain into the blood, raising the possibility of a similar role for other transporters. Multidrug resistance‐associated protein (MRP), a 190 kDa protein, similar to Pgp is also ABC transporter that has been implicated in the blood–brain barrier. The current study explores its role in opioid action. Immunohistochemically, it is localized in the choroid plexus in rats and can be selectively downregulated by antisense treatment at both the level of mRNA, as shown by RT‐PCR, and protein, as demonstrated immunohistochemically. Behaviorally, downregulation of MRP significantly enhances the analgesic potency of systemic morphine in MRP knockout mice and in antisense‐treated rats by lowering the blood–brain barrier. Following intracerebroventricular administration, a number of compounds, including some opioids, are rapidly secreted from the brain into the blood where they contribute to the overall analgesic effects by activating peripheral systems. MRP plays a role in this efflux. Downregulating MRP expression leads to a corresponding decrease in the transport and a diminished analgesic response from opioids administered intracerebroventricularly. Thus, the transporter protein MRP plays a role in maintaining the blood–brain barrier and modulates the activity of opioids. Synapse 67:609–619, 2013.

Hepatic metastasectomy in children

There are little data regarding the safety and efficacy of hepatic metastasectomy for solid tumors in childhood. We reviewed our institutional experience to assess operative mortality and morbidity, technique of resection, local control, and survival in pediatric patients undergoing liver resection for metastases.

Single-incision laparoscopic splenectomy in children

PURPOSE Single-incision laparoscopic surgery is being incorporated into the practices of many pediatric surgeons. Its superior cosmetic outcomes have resulted in increased patient- and parent-driven demand for the approach. This article describes a series of single-incision laparoscopic splenectomies (SSs) in children and compares outcomes with a historical series of standard laparoscopic splenectomies (LS). METHODS The medical records of patients who underwent standard splenectomy and SS at our institution between 2007 and 2010 were reviewed. Perioperative data were recorded. Descriptive comparisons were made between the SS and LS groups. RESULTS Seven patients underwent SS, and 4 underwent LS during the study period. Operative times for the SS group decreased as experience with the procedure accumulated and ultimately approached LS operative times. No conversions to a standard laparoscopic or open approach were required. No complications occurred. Length of stay and postoperative pain were similar in both groups. single-incision laparoscopic splenectomy provided excellent cosmetic outcomes. CONCLUSIONS Single-incision laparoscopic splenectomy is feasible in children. Its main benefit is improved cosmesis. It can be performed without detrimental increases in operative times or patient discomfort. Given an increased demand for the approach, it remains a viable option in children.