Repetitive single subarachnoid injections for trial administration of the intrathecal morphine pump in patients with intractable non-cancer pain -A case report-.

Since the early 1980s, the implantable intrathecal drug pump (ITDP) has been used increasingly to manage chronic pain. Prior to making a decision to implant an ITDP, trial administration of the intrathecal (IT) drug should be performed to estimate the effective dose for a starting set of implantable ITDPs. There is no standard method of trial IT drug administration, though. Therefore, this paper reports 20 cases of IT morphine trial with single and repetitive injections until the appropriate dose was attained with respect to analgesia and its side effects. The trial procedure was performed with daily sequential IT injections using morphine and 0.3% mepivacaine. Twelve out of the total of 20 patients had positive responses. Thus, it is inferred that daily sequential IT morphine injections combined with a placebo injection as a trial ITDP would be useful in evaluating the effectiveness and adverse effects of IT morphine infusion with clinically insignificant side effects.

N-terminally truncated variant of the mouse GAIP/RGS19 lacks selectivity of full-length GAIP/RGS19 protein in regulating ORL1 receptor signaling.

The regulators of G protein signaling (RGS) are a family of proteins with conserved RGS domains and play essential roles in regulating G protein-mediated signal transduction and physiological events. GAIP/RGS19 (G alpha interacting protein, also classified as RGS19), a member of the RGS family, has been shown to negatively regulate the signaling of many G protein-coupled receptors, including the opioid receptors. Two GAIP/RGS19 mRNA variants, resulted from an alternative splicing of exon 2 of the GAIP/RGS19 gene, were identified in multiple mouse tissues. One of the transcripts consists of a complete set of exons and encodes a full-length GAIP/RGS19 protein, and the other does not have exon 2 and therefore encodes an N-terminal 22 residue truncated short GAIP/RGS19 protein. When co-expressed with either the opioid-receptor-like (ORL1) receptor or one of the mu, delta, and kappa opioid receptors, by transfecting dual-expression plasmids into COS-7 cells, the full-length GAIP/RGS19 was more effective than the N-terminally truncated variant and was more selective in regulating the ORL1 receptor signaling than in regulating the mu, delta, and kappa opioid receptors, as measured by the effectiveness to increase the agonist-stimulated GTPase activity and to reverse the agonist-induced inhibition of cyclic AMP accumulation. In the same assays, the N-terminally truncated GAIP/RGS19 did not distinguish ORL1 from the mu, delta, and kappa opioid receptors. In contrast, co-expression of RGS4 with either ORL1 or opioid receptors showed the selectivity of RGS4 for regulating opioid receptors was mu > kappa > delta > ORL1, an order completely different from that of GAIP/RGS19. The results suggest that GAIP/RGS19 prefers regulating ORL1 receptor signaling over other opioid receptors, and that the N-terminal domain of GAIP/RGS19 plays a crucial role in its receptor preference.

Distance to the adult cervical epidural space.

BACKGROUND AND OBJECTIVES: Cervical epidural block is useful in the management of a variety of acute, chronic, and cancer-related pain syndromes involving the head, face, neck, and upper extremities. Knowledge of the depth from the skin to the cervical epidural space (DSES) may be helpful when performing cervical epidural block and may reduce the possibility of complications. We studied DSES in adults and its relationship with patient age, height, weight, and neck circumference. METHODS: The study included 816 patients. Cervical epidural block was performed at the C5-6, C6-7, and C7-T1 intervertebral space by a midline approach under fluoroscopic guidance. The depth to the epidural space from the skin was measured. RESULTS: DSES at C5-6, C6-7, and C7-T1 was 4.7 +/- 0.6 cm, 5.1 +/- 0.6 cm, 5.6 +/- 0.8 cm in males and 4.0 +/- 0.6 cm, 4.6 +/- 0.6 cm, 5.0 +/- 0.6 cm in females (mean +/- SD). Linear regression analysis revealed significant correlations between DSES and weight, neck circumference, and body mass index. CONCLUSION: DSES varies with cervical intervertebral space. DSES increases as one moves caudally. The greatest DSES was noted at C7-T1 in men, and the least was at C5-6 in women. DSES had a significant relationship with weight, neck circumference, and body mass index in both genders.