Altered functional properties of a TRPM2 variant in Guamanian ALS and PD.

Two related neurodegenerative disorders, Western Pacific amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia (PD), originally occurred at a high incidence on Guam, in the Kii peninsula of Japan, and in southern West New Guinea more than 50 years ago. These three foci shared a unique mineral environment characterized by the presence of severely low levels of Ca(2+) and Mg(2+), coupled with high levels of bioavailable transition metals in the soil and drinking water. Epidemiological studies suggest that genetic factors also contribute to the etiology of these disorders. Here, we report that a variant of the transient receptor potential melastatin 2 (TRPM2) gene may confer susceptibility to these diseases. TRPM2 encodes a calcium-permeable cation channel highly expressed in the brain that has been implicated in mediating cell death induced by oxidants. We found a heterozygous variant of TRPM2 in a subset of Guamanian ALS (ALS-G) and PD (PD-G) cases. This variant, TRPM2(P1018L), produces a missense change in the channel protein whereby proline 1018 (Pro(1018)) is replaced by leucine (Leu(1018)). Functional studies revealed that, unlike WT TRPM2, P1018L channels inactivate. Our results suggest that the ability of TRPM2 to maintain sustained ion influx is a physiologically important function and that its disruption may, under certain conditions, contribute to disease states.

A "Rash" Decision in Anesthetic Management: Benzyl Alcohol Allergy in the Perioperative Period.

Here, we present the case of a 54-year-old female presenting for outpatient ankle hardware removal who experienced severe total body pruritus along with a maculopapular rash persisting four days after the procedure. Patch testing demonstrated a sensitivity to benzyl alcohol, a preservative in propofol and several other anesthetics. The patient returned for left ankle arthroscopy a year later, and during that procedure, the anesthetic team avoided medications containing benzyl alcohol. This resulted in no pruritus or rash. Hypersensitivity reactions, ranging from contact dermatitis to anaphylaxis, are critical events in the perioperative period. Induction of general anesthesia has been implicated as the inciting event for perioperative hypersensitivity reactions. Benzyl alcohol is among a few excipients found in common anesthetic agents known to cause hypersensitivity reactions in susceptible patients. While reports of adult death are rare, infantile death due to benzyl alcohol has been described.

Expression profile of PRAF2 in the human brain and enrichment in synaptic vesicles.

PRA1 domain family, member 2 (PRAF2) is a novel 19-kDa protein with a prenylated Rab acceptor 1 (PRA1) motif and four transmembrane domains. Our previous studies revealed that PRAF2 is highly expressed in the brain and serves as a candidate prognostic marker in neuroblastoma (NB). PRAF2 is related to proteins PRAF1 (PRA1, prenylin, Yip3) and PRAF3 (GTRAP3-18, JWA, Arl6-IP5), both of which are enriched in the brain and implicated in cellular transport and endo/exocytic vesicle trafficking. However, the function for PRAF2 remains unknown. In this study, we analyzed the distribution and localization of PRAF2 in the mature human brain using two new antibodies specific for the protein. Analysis by immunohistochemistry revealed that in the human cerebellum, the PRAF2 protein was strongly expressed in Purkinje cells and, more moderately, in cells of the molecular and the granular layers. In the cerebral cortex, hippocampus, and lateral ventricles, PRAF2 protein was detected in neuronal cells, but not in non-neuronal cells. Intriguingly, immunoblot analysis revealed that PRAF2 is enriched in synaptic vesicles (SVs) prepared from rat brains. The expression of PRAF2 in specific regions of the brain including SVs suggest an important physiological function for this novel protein, possibly by participating in multiple aspects of SV maturation, transport, and signal transmission.

Expression of prenylated Rab acceptor 1 domain family, member 2 (PRAF2) in neuroblastoma: correlation with clinical features, cellular localization, and cerulenin-mediated apoptosis regulation.

PURPOSE: Prenylated Rab acceptor 1 domain family, member 2 (PRAF2) is a novel 19-kDa protein that has recently been implicated in human cancer. In the present study, we analyzed for the first time PRAF2 mRNA expression in a large set of human tumors. The high expression in neuroblastic tumors prompted us to analyze PRAF2 expression correlations with genetic and clinical features of these tumors. In addition, we determined the localization of PRAF2 protein in neuroblastoma cells and studied its regulation in apoptosis. EXPERIMENTAL DESIGN: Affymetrix microarray analysis was done with a set of 41 different tumor types (1,426 samples) in the public domain, a set of three different neuroblastic tumor types (110 samples), and a panel of 25 neuroblastoma cell lines. The subcellular localization of endogenous PRAF2 in neuroblastoma cells was identified by immunofluorescence microscopy and apoptosis detected by Annexin V staining and poly(ADP-ribose) polymerase cleavage. RESULTS: PRAF2 mRNA was detected in 970 of 1,426 samples in the public data set. All 110 neuroblastic tumors expressed PRAF2 at higher levels than any other tumor examined. Importantly, PRAF2 expression levels significantly correlated with the following clinical features: patient age at diagnosis (P = 6.19 x 10(-5)), survival (P = 1.32 x 10(-3)), International Neuroblastoma Staging System stage (P = 2.86 x 10(-4)), and MYCN amplification (P = 3.74 x 10(-3)). PRAF2 localized in bright cytoplasmic punctae and protein levels increased in neuroblastoma cells that underwent cerulenin-induced apoptosis. CONCLUSIONS: Elevated PRAF2 expression levels correlated with unfavorable genetic and clinical features, suggesting PRAF2 as a candidate prognostic marker of neuroblastoma.

Report on Implementation, Use, and Sustainability of a Labor Epidural Service in Georgetown, Guyana.

BACKGROUND: The use of epidural analgesia for laboring women is generally unavailable at public hospitals in Guyana despite favorable utilization rates in private institutions. In 2014, a healthcare team completed a targeted mission aimed at neuraxial analgesia training of providers at the preeminent public hospital in Georgetown, Guyana. This study evaluates the impact of the training, including provider attitudes, use, and barriers. METHODS: A prospective, mixed methods study of all obstetric, nursing, and anesthesiology providers at Georgetown Public Hospital Corporation was completed. Quantitative assessment of the posttraining use of epidural analgesia at 2 and 6 months was documented. Provider surveys were distributed anonymously at 2 months posttraining. Targeted interviews were completed from a random sampling of providers at 6 months; qualitative analysis of interviews formulated the basis for reporting limitations and barriers. RESULTS: Providers surveyed included 7 anesthesia providers and 24 obstetrics providers. Respondents believed Guyanese women should be offered epidural analgesia (93%), epidurals could be performed safely (87%), and Guyana has the resources necessary for routine use (81%). In assessing epidural knowledge, anesthesia providers achieved 60% correct response rate compared to 84% among obstetrics providers. Nurse anesthetists placed 16 epidurals following training. However, placement ceased after 2 months. The largest barriers to placement were unavailable anesthesia staff (63%), lack of supplies (16%), and insufficient nursing staff to monitor patients with epidurals (11%). CONCLUSIONS: A 1-week mission achieved widespread Guyanese provider acceptance despite a lack of previous experience. However, barriers proved insurmountable to achieving a sustainable, independently functioning epidural analgesia program.

Anesthetic Considerations in a Patient with Myotonic Dystrophy for Hip Labral Repair.

Myotonic Dystrophy (DM) affects multiple organ systems. Disorders such as hyperthyroidism, progressive musculoskeletal weakness, cardiac dysrhythmias, hypoventilation, and cognitive-behavioral disorders may be present in these patients. Thorough preoperative assessment and anesthetic planning are required to minimize the risk of anesthetic complications. Patients with DM can exhibit exquisite sensitivity to sedatives, neuromuscular blocking agents, and volatile anesthetics, resulting in potential postoperative complications. There is limited literature available on successful anesthetic techniques for the DM patient. We present this case report to add to our current fund of knowledge.

Truncal blocks for perioperative pain management: a review of the literature and evolving techniques.

As the American healthcare system continues to evolve and reimbursement becomes tied to value-based incentive programs, perioperative pain management will become increasingly important. Regional anesthetic techniques are only one component of a successful multimodal pain regimen. In recent years, the use of peripheral and paraneuraxial blocks to provide chest wall and abdominal analgesia has gained popularity. When used within a multimodal regimen, truncal blocks may provide similar analgesia when compared with other regional anesthetic techniques. While there are other reviews that cover this topic, our review will also highlight the emerging role for serratus plane blocks, pectoral nerve blocks and quadratus lumborum blocks in providing thoracic and abdominal analgesia.

Inhalational anaesthetics and n-alcohols share a site of action in the neuronal Shaw2 Kv channel.

BACKGROUND AND PURPOSE: Neuronal ion channels are key targets of general anaesthetics and alcohol, and binding of these drugs to pre-existing and relatively specific sites is thought to alter channel gating. However, the underlying molecular mechanisms of this action are still poorly understood. Here, we investigated the neuronal Shaw2 voltage-gated K(+) (K(v)) channel to ask whether the inhalational anaesthetic halothane and n-alcohols share a binding site near the activation gate of the channel. EXPERIMENTAL APPROACH: Focusing on activation gate mutations that affect channel modulation by n-alcohols, we investigated n-alcohol-sensitive and n-alcohol-resistant K(v) channels heterologously expressed in Xenopus oocytes to probe the functional modulation by externally applied halothane using two-electrode voltage clamping and a gas-tight perfusion system. KEY RESULTS: Shaw2 K(v) channels are reversibly inhibited by halothane in a dose-dependent and saturable manner (K(0.5)= 400 microM; n(H)= 1.2). Also, discrete mutations in the channel's S4S5 linker are sufficient to reduce or confer inhibition by halothane (Shaw2-T330L and K(v)3.4-G371I/T378A respectively). Furthermore, a point mutation in the S6 segment of Shaw2 (P410A) converted the halothane-induced inhibition into halothane-induced potentiation. Lastly, the inhibition resulting from the co-application of n-butanol and halothane is consistent with the presence of overlapping binding sites for these drugs and weak binding cooperativity. CONCLUSIONS AND IMPLICATIONS: These observations strongly support a molecular model of a general anaesthetic binding site in the Shaw2 K(v) channel. This site may involve the amphiphilic interface between the S4S5 linker and the S6 segment, which plays a pivotal role in K(v) channel activation.