Nerve growth factor (NGF) treatment of PC12 cells induced a 2.8-fold increase in protein kinase C activity concomitant with ditfercntiation and acquisition of neuritcs. PKC protein isoforms were separated by sequential chromatography on DEAE-Sephacel/hydroxylapatite.A broad peak of PKC activity elutcd which corresponded to the alpha PKC isoform. In control cells, message for all six PKC isofotms was detected and expressed as cpsilon~reta=gamma~deltazbetaralpha.Western blot of whole cell lysatcs revcalcd a large increase in the beta,,, while slight changes were observed for the other five PKC isoforms during treatment (I-14 days) with NGF (50 ng&nl). In parallel, coordinate changes in the expression of the individual transcripts for the six isoforms occurred during NGF treatment. Induction and accumulation of PKC beta,, may play a role in maintcnunce of neuronal morphology.
Brain tissue from 1068 donors was analyzed for RNA quality as a function of postmortem interval (PMI) and years in storage. Approximately 83% of the cortical and cerebellar samples had an RNA integrity number (RIN) of 6 or greater, indicating their likely suitability for real-time quantitative polymerase chain reaction research. The average RIN value was independent of the PMI, up to at least 36 hours. The RNA quality for specific donated brains could not be predicted based on the PMI. Individual samples with a low PMI could have a poor RIN value, while a sample with a PMI over 36 hours may have a high RIN value. The RIN values for control brain donors, all of whom died suddenly and unexpectedly, were marginally higher than for individuals with clinical brain disorders. Polymerase chain reaction (PCR) analysis of samples confirmed that RIN values were more critical than PMI for determining suitability of tissue for molecular biological studies and samples should be matched by their RIN values rather than PMI. Importantly, PCR analysis established that tissue stored up to 23 years at −80°C yielded high-quality RNA. These results confirm that postmortem human brain tissue collected by brain and tissue banks over decades can serve as high quality material for the study of human disorders.
There is a crucial need to develop a better understanding of how the religious orientations of teachers impact their development and enactment of professional teaching identities. This article identifies 5 key questions that can help educators begin to uncover conscious and unconscious ways that their religious identifications impact why they enter the profession, how they relate to students, and the instructional decisions that they make to support learning. When articulating these questions, the author uses specific examples from a qualitative case study that explored how teachers' religious orientations influenced their classroom practice in public elementary schools. A professional development model is outlined that will assist educators in further consideration of how their religious positions may impact their professional work.
Background
Chlorhexidine is a skin disinfectant that reduces skin and mucous membrane bacterial colonization and inhibits organism growth. Despite numerous studies assessing chlorhexidine safety in term infants, residual concerns have limited its use in hospitalized neonates, especially low birth weight preterm infants. The aim of this study was to assess the potential neurotoxicity of chlorhexidine on the developing central nervous system using a well-established in vitro model of neurite outgrowth that includes laminin and L1 cell adhesion molecule (L1) as neurite outgrowth promoting substrates.
Methods
Cerebellar granule neurons are plated on either poly L-lysine, L1 or laminin. Chlorhexidine, hexachlorophene or their excipients are added to the media. Neurons are grown for 24 h, then fixed and neurite length measured.
Results
Chlorhexidine significantly reduced the length of neurites grown on L1 but not laminin. Chlorhexidine concentrations as low as 125 ng/ml statistically significantly reduced neurite length on L1. Hexachlorophene did not affect neurite length.
Conclusion
Chlorhexidine at concentrations detected in the blood following topical applications in preterm infants specifically inhibited L1 mediated neurite outgrowth of cerebellar granule neurons. It is now vital to determine whether the blood brain barrier is permeable to chlorhexidine in preterm infants.
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