A rapid screening method for population-specific neuronal motogens, substrates and associated signaling pathways

We developed and characterized an assay that allows for rapid examination of migration of specific neuronal populations within a mixed population using the Boyden chamber principle. Migration of cerebellar interneurons and granule cells was examined using mice expressing enhanced green fluorescent protein (eGFP) under the glutamate decarboxylase (GAD(65)) and growth-associated protein-43 (GAP43) promoters, respectively. Brain-derived neurotrophic factor (BDNF) was used as the prototypic motogen for both populations. Fluorescent light-blocking inserts (FluoroBlok) with different pore sizes and densities were compared in a two-compartment assay. Immunodetection of polarity markers and nuclear staining indicated that dendrites and somata are preferentially extended through the pores in response to BDNF. Inserts coated with extracellular matrix (ECM) proteins were used to examine interactions between BDNF and the ECM during migration. ECM proteins alone stimulated migration when the lower side of the insert was coated, however coating of both sides of the insert slowed migration when compared to poly-D-lysine. Addition of a PI 3-kinase inhibitor to the lower compartment blocked BDNF-stimulated migration of both populations while a Src inhibitor reduced laminin-stimulated migration of interneurons, but not granule cells. We also examined use of neurons cultured from GAD(65)-eGFP mice as a reporter system for promoter activity. GAD(65)-eGFP mice may also be useful as a model for promoter regulation and the potential confounding effects of eGFP induction by the stimuli are also addressed. This assay allows for rapid analysis of motogens, substrates and signaling pathways that regulate migration of selected neuronal populations.     

Evaluation of a synchronous twin-pulse technique for shock wave lithotripsy: a prospective randomized study of effectiveness and safety in comparison to standard single-pulse technique

OBJECTIVE

To asses the efficacy and safety of bidirectional synchronous twin‐pulse extracorporeal shock wave lithotripsy (ESWL) compared with standard ESWL.

PATIENTS AND METHODS

Between March 2003 and December 2006, 240 patients with a radio‐opaque single renal stone of ≤25 mm were randomized to treatment either by the Twinheads (TH) lithotripter (FMD, Lorton, Virginia, USA) or the Dornier Lithotripter S (DLS, Dornier MedTech Europe GmbH, Germering, Germany). Before and after ESWL, urinary N‐acetyl‐B‐glucosaminidase (NAG) levels were assessed and patients were evaluated with dynamic MRI. The efficacy and complications were compared, with success defined as no residual fragments.

RESULTS

For stones of >10 mm the rate for the failure of disintegration was 13.3% for the DLS vs 1.4% for the TH (P = 0.009). For stones of ≤10 mm the stone‐free rate was 74.4% for the TH vs 67.7% for the DLS (P = 0.6), while for stones of >10 mm it was 78.1% and 66.7%, respectively (P = 0.14). The median (range) number of sessions in both groups was 2 (1–5). After ESWL urinary NAG levels were increased significantly in both groups; in the TH group it declined below the level before ESWL after 2 days, while in the DLS group it remained high after 7 days. In the DLS group four patients developed subcapsular or parenchymal haematoma after ESWL, vs none in the TH group. There was loss of corticomedullary differentiation after ESWL in three patients in the DLS group and only one in the TH group. In the DLS group there was a statistically significantly decrease in bilateral renal perfusion after ESWL, but no changes in the TH group.

CONCLUSIONS

Synchronous twin‐pulse ESWL has clinical advantages over standard ESWL in terms of safety and efficacy.     

Educational interventions in end-of-life care: part II: psychometric development of an instrument to measure nursing comfort after an educational intervention in end-of-life care: the "Comfort Level Caring for Dying Infants" (CLCDI)

PURPOSE: This article describes the psychometric development of an instrument that was used to measure nurses' comfort level with care of the dying before and after an educational intervention. PARTICIPANTS: 112 registered nurses working in a level III neonatal intensive care unit (NICU) were included. METHOD: Using a quantitative method, the validity and reliability of the instrument, "Comfort level in Caring for Dying Infants" (CLCDI), was assessed for content validity and internal consistency. RESULTS: The instrument was found to be reliable, but the content validity was questionable, and merits further testing. CONCLUSIONS: Given the results of the current study, the authors plan further refinements to the instrument.     

Educational interventions in end-of-life care: part I: an educational intervention responding to the moral distress of NICU nurses provided by an ethics consultation team.

PURPOSE: This study was conducted to assess whether neonatal nurses who care for dying infants could be assisted in their knowledge and comfort via an educational intervention provided by hospital ethics committee members and hospice specialists. PARTICIPANTS: Eighty-two registered nurses working in a level III neonatal intensive care unit (NICU) were included. METHODS AND DESIGN: This was a quantitative pretest, intervention, post-test design with a single group undergoing educational sessions in the 6 areas of pain management, symptom management, ethical/legal issues, communication/culture, spiritual/anxiety, and prevention of compassion fatigue. MAIN OUTCOME MEASUREMENTS: An instrument, "Comfort in Caring for Dying Infants" (CLCDI), was developed to assess pre- and posteducational knowledge and comfort in these areas. RESULTS: There were statistically significant higher levels of comfort and knowledge in care for dying infants in the areas of ethical/legal issues and symptom management after the educational programs. Although not statistically significant, mean scores were higher after the educational sessions on pain management, spirituality/anxiety, and prevention of compassion fatigue. The communication/culture module scores were lower in the post-test administration. CONCLUSIONS: Education by hospice experts in the NICU can assist nurses' comfort with care of the dying infant. In addition, ongoing support is highly desirable for all staff participating in such care. The authors suggest incident debriefings from outside experts, debriefing after each infant's death, multidisciplinary meetings for the whole team, and having sessions of lessons learned on infant death cases.     

A potent, covalent inhibitor of orotidine 5'-monophosphate decarboxylase with antimalarial activity

Orotidine 5'-monophosphate decarboxylase (ODCase) has evolved to catalyze the decarboxylation of orotidine 5'-monophosphate without any covalent intermediates. Active site residues in ODCase are involved in an extensive hydrogen-bonding network. We discovered that 6-iodouridine 5'-monophosphate (6-iodo-UMP) irreversibly inhibits the catalytic activities of ODCases from Methanobacterium thermoautotrophicum and Plasmodium falciparum. Mass spectral analysis of the enzyme-inhibitor complex confirms covalent attachment of the inhibitor to ODCase accompanied by the loss of two protons and the iodo moiety. The X-ray crystal structure (1.6 A resolution) of the complex of the inhibitor and ODCase clearly shows the covalent bond formation with the active site Lys-72 [corrected] residue. 6-Iodo-UMP inhibits ODCase in a time- and concentration-dependent fashion. 6-Iodouridine, the nucleoside form of 6-iodo-UMP, exhibited potent antiplasmodial activity, with IC50s of 4.4 +/- 1.3 microM and 6.2 +/- 0.7 microM against P. falciparum ItG and 3D7 isolates, respectively. 6-Iodouridine 5'-monophosphate is a novel covalent inhibitor of ODCase, and its nucleoside analogue paves the way to a new class of inhibitors against malaria.