Use of Dexmedetomidine for Postoperative Pain Management Following Spine Fusion Surgery in a Highly Opioid-Tolerant Patient.

A 51-year-old man with metastatic renal cell carcinoma whose fentanyl requirement was 3000-4000 µg/h in inpatient hospice presented for a thoracic (T) vertebral 4-10 posterior spinal fusion for a lytic T7 compression fracture. He underwent total intravenous (IV) anesthesia with propofol, remifentanil, and ketamine; liposome bupivacaine was locally infiltrated at the end of the case. Following extubation on postoperative day (POD) 1, he had severe pain refractory to high-dose IV fentanyl patient control analgesia and ketamine infusion. His pain dramatically improved after a dexmedetomidine infusion was added and titrated to the analgesic effect. He participated in neurological examinations and fulfilled both surgical and pain management goals without side effects. Dexmedetomidine was successfully weaned off on POD 3.

Insulin excites anorexigenic proopiomelanocortin neurons via activation of canonical transient receptor potential channels.

Proopiomelanocortin (POMC) neurons within the hypothalamic arcuate nucleus are vital anorexigenic neurons. Although both the leptin and insulin receptors are coupled to the activation of phosphatidylinositide 3 kinase (PI3K) in POMC neurons, they are thought to have disparate actions on POMC excitability. Using whole-cell recording and selective pharmacological tools, we have found that, similar to leptin, purified insulin depolarized POMC and adjacent kisspeptin neurons via activation of TRPC5 channels, which are highly expressed in these neurons. In contrast, insulin hyperpolarized and inhibited NPY/AgRP neurons via activation of KATP channels. Moreover, Zn(2+), which is found in insulin formulations at nanomolar concentrations, inhibited POMC neurons via activation of KATP channels. Finally, as predicted, insulin given intracerebroventrically robustly inhibited food intake and activated c-fos expression in arcuate POMC neurons. Our results show that purified insulin excites POMC neurons in the arcuate nucleus, which we propose is a major mechanism by which insulin regulates energy homeostasis.

Age of Parkinson's disease onset as a predictor for the development of dyskinesia.

The risk of developing levodopa-associated dyskinesia is known to vary inversely with the age of Parkinson's disease onset. This study quantifies dyskinesia risks for different Parkinson's onset ages in a patient population treated at the Parkinson's Disease Research, Education, and Clinical Center at the San Francisco Veterans Affairs Medical Center. Medical records were reviewed to determine age of Parkinson's onset, medication history, and dyskinesia onset. Dyskinesia risks were determined by using Kaplan-Meier analysis. Cox proportional hazard models were used to compare age groups and to perform multivariate modeling. This study included 109 patients with Parkinson's, 105 of whom had onset of symptoms after 1989. At 5 years of levodopa treatment, the dyskinesia risk for patients with onset age 40-49 was 70%, decreasing to 42% for onset ages 50-59, 33% for onset ages 60-69, and 24% for onset ages 70-79. Pairwise comparisons between the 40-49 age group and the other age groups were statistically significant in time-to-event models. After 5 years of levodopa treatment, dyskinesia risks became uniformly high regardless of age of onset. These results suggest it is appropriate to use different baseline dyskinesia risks in clinical decision-making for patients on the basis of their ages of onset. However, the most significant difference occurs between ages 40-49 and ages 50-79, and if more than 5 years of levodopa therapy are anticipated, dyskinesia risk may have less utility when deciding upon Parkinson's therapy. Drug studies for Parkinson's disease should also take age of Parkinson's onset into account when analyzing dyskinesia outcomes.

Fluoroscopic, EMG-guided injection of botulinum toxin into the longus colli for the treatment of anterocollis.

BACKGROUND: Anterocollis is a form of cervical dystonia characterized by forward neck flexion. While botulinum toxin is the treatment of choice for cervical dystonia, patients with anterocollis, who receive injections into the sternocleidomastoid and anterior scalene muscles, represent a disproportionate number of treatment failures. Deep cervical muscles such as the longus colli likely play an important role in neck flexion but are not routinely injected. OBJECTIVE: To describe a technique for longus colli injection in cases of anterocollis and to report the clinical outcomes of 10 such injections of botulinum toxin. METHODS: Three patients were referred for evaluation and treatment of anterocollis. All had previous treatment failures with sternocleidomastoid/anterior scalene injections or no activity noted on needle EMG investigation of these muscles. All patients received injections of botulinum toxin into the longus colli under fluoroscopic and EMG guidance. RESULTS: All patients experienced symptomatic improvement (eight of 10 injections). Two patients reported mild dysphagia without serious complications after dose increases in botulinum toxin. CONCLUSIONS: Incomplete muscle selection may be one cause of treatment failures in anterocollis. Deep cervical flexors such as the longus colli represent an under-recognized potential target for symptomatic treatment of anterocollis.

HIPK2 represses beta-catenin-mediated transcription, epidermal stem cell expansion, and skin tumorigenesis.

Transcriptional control by beta-catenin and lymphoid enhancer-binding factor 1 (LEF1)/T cell factor regulates proliferation in stem cells and tumorigenesis. Here we provide evidence that transcriptional co repressor homeodomain interacting protein kinase 2 (HIPK2) controls the number of stem and progenitor cells in the skin and the susceptibility to develop squamous cell carcinoma. Loss of HIPK2 leads to increased proliferative potential, more rapid G1-S transition in cell cycle, and expansion of the epidermal stem cell compartment. Among the critical regulators of G1-S transition in the cell cycle, only cyclin D1 is selectively up-regulated in cells lacking HIPK2. Conversely, overexpression of HIPK2 suppresses LEF1/beta-catenin-mediated transcriptional activation of cyclin D1 expression. However, deletion of the C-terminal YH domain of HIPK2 completely abolishes its ability to recruit another transcriptional corepressor CtBP and suppress LEF1/beta-catenin-mediated transcription. To determine whether loss of HIPK2 leads to increased susceptibility to tumorigenesis, we treat wild-type, Hipk2+/-, andHipk2-/- mice with the two-stage carcinogenesis protocol. Our results indicate that more skin tumors are induced in Hipk2+/- and Hipk2-/- mutants, with most of the tumors showing shortened incubation time and malignant progression. Together, our results indicate that HIPK2 is a tumor suppressor that controls proliferation by antagonizing LEF1/beta-catenin-mediated transcription. Loss of HIPK2 synergizes with activation of H-ras to induce tumorigenesis.