Amyloid-beta impairs development of neuronal progenitor cells by oxidative mechanisms

Neuronal progenitor cells (NPCs) are being considered for treatment of neurodegenerative diseases associated with beta-amyloidosis: Alzheimer's disease (AD) and Down syndrome (DS). However, the neurotoxic properties of amyloid-beta peptide (Abeta) may impair survival and differentiation of transplanted NPCs. Hence, we studied the influence of Abeta on development of human NPCs--proliferation, migration, formation of colonies of neurons, formation processes--in culture. Pre-fibrillized human Abeta1-40 blocked development of neuronal colonies. NPC development was impaired in the presence of soluble Abeta1-40 (1.75-7 microM), and NPC differentiation into large and small neurons was altered, as demonstrated by morphometry. Antioxidant vitamin E partially abolished these effects, but not the reduced formation of neuronal processes. NPCs cultured with 7 microM Abeta1-40 accumulated Abeta monomers and oligomers and contained higher levels of protein carbonyls and lipid peroxidation products HNE and MDA. We suggest that Abeta1-40 impairs development of NPCs by oxidative damage. Hence, a prerequisite of successful neuroreplacement therapy using NPCs in AD and DS/AD may be removal of amyloid-beta and antioxidative treatment.     

PACAP up-regulates the expression of apolipoprotein D in 3T3-L1 adipocytes. DRG/3T3-L1 co-cultures study

The existence of a cross-talk between nerves and fatty tissue is increasingly recognized. Using co-cultures of dorsal root ganglion (DRG)-derived cells and 3T3-L1 adipocytes, we have previously shown that the presence of fat cells enhances neurite outgrowth and number of synapses. Vice versa, neural cells induced expression of neurotrophic adipokines apolipoprotein D and E (ApoD, ApoE) and angiopoietin-1 (Ang-1) by adipocytes. Here, we tested whether pituitary adenylate cyclase-activating peptide (PACAP), which is released by sensory fibres and causes Ca(2+) influx into fat cells, is involved in ApoD induction. Using 3T3-L1 cell cultures, we found that PACAP at a dose of 1 nM up-regulated the expression of ApoD protein and mRNA approx. 2.5 fold. This effect was driven by ERK1/2 acting upon PAC1/VPAC2 receptors. In turn, PACAP-treated 3T3-L1 adipocytes in co-cultures with DRG cells enhanced neurite ramification of neurofilament 200 (NF200)-positive neurons (measured using fluorescence microscopy) and neurofilament 68 protein levels (measured using Western blot analysis). This effect could be blocked using the PAC1/VPAC2 antagonist PACAP(6-38). Scanning cytometry revealed PACAP/ApoD induced low density lipoprotein receptors (LDLR) and ApoE receptor 2 (apoER2) in NF200-positive cells. Thus, a bidirectional loop seems to exist regulating the innervation of fatty tissues: PACAP released from sensory fibres might stimulate fat cells to synthesize neurotrophic adipokines, which, in turn, support peripheral innervation.     

Mycophenolate mofetil (MMF) treatment efficacy in children with primary and secondary glomerulonephritis

Introduction

The aim of our study was to analyse the efficacy and safety of mycophenolate mofetil (MMF) as part of the complex immunosuppressive therapy in children with different types of primary and secondary glomerulonephritis, who were not eligible for the standard treatment routine suggested by evidence-based guidelines.

Material and methods

The study group comprised 85 children with proteinuric glomerulopathies hospitalized between 2007 and 2010, who were non-responders to immunosuppressive therapy. The dose of MMF was established as 1 g/m²/24 h. Remission was defined as negative proteinuria in three consecutive urinalyses.

Results

The patients were divided into 4 groups: idiopathic nephrotic syndrome (n = 35), primary glomerulonephritis (n = 15), auto-antibody associated glomerulonephritis (n = 20) and lupus nephropathy (LN, n = 15). Ten patients from the first group (29%) and 5 patients each from the second and third group (34% and 25% respectively) did not respond to MMF therapy. On the other hand, all the children diagnosed with LN have reached clinical and biochemical remission.

Conclusions

Alternative rescue MMF therapy should always be taken into consideration in proteinuric patients who are non-responders to steroids, cyclosporine A and cyclophosphamide in whom the initial glomerular filtration rate is higher than 60 ml/min/1.73m². It is recommended that MMF be administered as part of the standard treatment regimen in patients diagnosed with lupus nephropathy. In these groups of patients, the potent benefits of this therapy are higher than expected side-effects.     

An in vitro spectroscopic analysis to determine the chemical composition of the precipitate formed by mixing sodium hypochlorite and chlorhexidine

Introduction

The purpose of this in vitro study was to determine the chemical composition of the precipitate formed by mixing sodium hypochlorite (NaOCl) and chlorhexidine (CHX) and the relative molecular weight of the components.

Methods

Using commercially available CHX gluconate, a 2% solution was formed and mixed in a 1:1 ratio with commercially available NaOCl producing a brown precipitate. The precipitate as well as a mixture of precipitate and pure CHX diacetate was then analyzed using one-dimensional and two-dimensional NMR spectroscopy.

Results

The one-dimensional and two-dimensional NMR spectra were fully assigned in terms of chemical shifts of all proton and carbon atoms in intact CHX. This permitted identification of two major CHX breakdown products, neither of which are parachloroaniline (PCA). Both products are related to PCA in that they are parasubstituted benzene compounds. Based on NMR data and a proposed mechanism of CHX breakdown, the products appear to be parachlorophenylurea (PCU) and parachlorophenylguanidyl-1,6-diguanidyl-hexane (PCGH).

Conclusions

Based on this in vitro study, the precipitate formed by NaOCl and CHX is composed of at least two separate molecules, all of which are smaller in size than CHX. Along with native CHX, the precipitate contains two chemical fragments derived from CHX (PCU and PCGH), neither of which are PCA.     

Is it time to change the goals of lipid management in type 1 diabetes mellitus? Changes in apolipoprotein levels during the first year of type 1 diabetes mellitus. Prospective InLipoDiab1 study

IntroductionApolipoprotein complement is a critical determinant of lipoprotein function and metabolism. The relation between exogenous insulin and apolipoproteins (apos) in newly diagnosed type 1 diabetes mellitus (T1DM) has not yet been studied extensively. The aim of this study was to prospectively observe the changes in serum apos AI (apo AI) and AII (apo AII) in patients with newly diagnosed T1DM and their association with the daily insulin requirement.Material and methodsThirty-four participants of the InLipoDiab1 study aged 26 (IQR: 22–32) were enrolled in this analysis. Apolipoprotein AI and AII concentrations were assessed at diagnosis and at follow-up after 3 weeks, 6 months, and 1 year of insulin treatment. The daily dose of insulin (DDI) was calculated as the amount of short- and long-acting insulin at discharge from the hospital and at follow-up visits.ResultsThe changes in apo AI concentration were observed after 3 weeks of insulin treatment (p = 0.04), with the largest increase between 3 weeks and 6 months of observation (p < 0.001). Apolipoprotein AII level did not change significantly after 3 weeks, while a significant increase was observed between 3 weeks and 6 months of treatment (p < 0.001). The correlations between DDI and apo concentration were not statistically significant.ConclusionsIn the first year of T1DM, there is a significant increase in apos concentration. Due to the significant deviation of apos concentration from accepted norms, changes in the recommendations of lipid control criteria in T1DM may be considered.     

The role of sphingosine kinase-1 in EGFRvIII-regulated growth and survival of glioblastoma cells

We have previously shown that high expression levels of the lipid kinase sphingosine kinase-1 (SphK1) correlate with poor survival of glioblastoma (GBM) patients. In this study we examined the regulation of SphK1 expression by epidermal growth factor receptor (EGFR) signaling in GBM cells. As the EGFR gene is often overexpressed and mutated in GBM, and EGFR has been shown to regulate SphK1 in some cell types, we examined the effect of EGF signaling and the constitutively active EGFRvIII mutant on SphK1 in GBM cells. Treatment of glioma cell lines with EGF led to increased expression and activity of SphK1. Expression of EGFRvIII in glioma cells also activated and induced SphK1. In addition, siRNA to SphK1 partially inhibited EGFRvIII-induced growth and survival of glioma cells as well as ERK MAP kinase activation. To further evaluate the connection between EGFR and SphK1 in GBM we examined primary neurosphere cells isolated from fresh human GBM tissue. The GBM-derived neurosphere cell line GBM9, which forms GBM-like tumors intracranially in nude mice, maintained expression of EGFRvIII in culture and had high levels of SphK1 activity. EGFR inhibitors modestly decreased SphK1 activity and proliferation of GBM9 cells. More extensive blockage of SphK1 activity by a SphK inhibitor, potently blocked cell proliferation and induced apoptotic cell death of GBM9 cells. Thus, SphK1 activity is necessary for survival of GBM-derived neurosphere cells, and EGFRvIII partially utilizes SphK1 to further enhance cell proliferation.     

Improving performance and self-efficacy of novice nurses using hybrid simulation-based mastery learning

Aim

Acute chest pain is a commonly encountered symptom in hospital medical/surgical units; however, almost half of nurses in their second year of clinical experience in our facility have reported struggling to care for acute chest pain patients. We developed, implemented, and examined the effectiveness of a simulation-based, mastery learning clinical nursing educational program to improve self-efficacy and performance in caring for patients with acute chest pain.

Methods

The study adopted a single-site, single-cohort design using simulation-based performance assessment and self-efficacy surveys on a convenience sample of 37 second-year clinical nurse participants in multi-stage hybrid mastery learning educational intervention using asynchronous e-learning, and hands-on simulation training and assessment with feedback on caring for chest pain patients. Performance assessments and self-efficacy surveys were administered pre-, post-, and 5 months post-intervention.

Results

Clinical performance on the post- and 5 months follow-up assessments were significantly higher than those for the pre-test (P < .0001). The self-efficacy scores for the post- and the 5 months follow-up assessments were significantly higher than the pre-course scores (P < .0001). Participants' self-efficacy perceptions were positively correlated with their performances at 5 months post-intervention.

Conclusion

Performance and self-efficacy of novice nurses in caring for acute chest pain patients improved significantly with the multi-stage hybrid mastery learning educational intervention, with improvements retained 5 months post-intervention. The results suggest the applicability of simulation-based mastery learning in a clinical setting for novice nurses to attain specific skills, and raise their self-perception of competence to care for patients in acute settings.