Synaptically-competent neurons derived from canine embryonic stem cells by lineage selection with EGF and noggin

Pluripotent stem cell lines have been generated in several domestic animal species; however, these lines traditionally show poor self-renewal and differentiation. Using canine embryonic stem cell (cESC) lines previously shown to have sufficient self-renewal capacity and potency, we generated and compared canine neural stem cell (cNSC) lines derived by lineage selection with epidermal growth factor (EGF) or Noggin along the neural default differentiation pathway, or by directed differentiation with retinoic acid (RA)-induced floating sphere assay. Lineage selection produced large populations of SOX2+ neural stem/progenitor cell populations and neuronal derivatives while directed differentiation produced few and improper neuronal derivatives. Primary canine neural lines were generated from fetal tissue and used as a positive control for differentiation and electrophysiology. Differentiation of EGF- and Noggin-directed cNSC lines in N2B27 with low-dose growth factors (BDNF/NT-3 or PDGFαα) produced phenotypes equivalent to primary canine neural cells including 3CB2+ radial progenitors, MOSP+ glia restricted precursors, VIM+/GFAP+ astrocytes, and TUBB3+/MAP2+/NFH+/SYN+ neurons. Conversely, induction with RA and neuronal differentiation produced inadequate putative neurons for further study, even though appropriate neuronal gene expression profiles were observed by RT-PCR (including Nestin, TUBB3, PSD95, STX1A, SYNPR, MAP2). Co-culture of cESC-derived neurons with primary canine fetal cells on canine astrocytes was used to test functional maturity of putative neurons. Canine ESC-derived neurons received functional GABAA- and AMPA-receptor mediated synaptic input, but only when co-cultured with primary neurons. This study presents established neural stem/progenitor cell populations and functional neural derivatives in the dog, providing the proof-of-concept required to translate stem cell transplantation strategies into a clinically relevant animal model. © 2011 Wilcox et al

LPS from P. gingivalis

Objective. Oral inflammatory pathologies are linked to increased oxidative stress, thereby partly explaining their relevance in the etiology of systemic disorders. The purpose of this work was to determine the degree to which LPS from Porphyromonas gingivalis, the primary pathogen related to oral inflammation, altered gingival mitochondrial function and reactive oxygen species generation. Methods. Human gingival fibroblast (HGF-1) cells were treated with lipopolysaccharide of P. gingivalis. Mitochondrial function was determined via high-resolution respirometry. Results. LPS-treated HGF-1 cells had significantly higher mitochondrial complex IV and higher rates of mitochondrial respiration. However, this failed to translate into greater ATP production, as ATP production was paradoxically diminished with LPS treatment. Nevertheless, production of the reactive H2O2 was elevated with LPS treatment. Conclusions. LPS elicits an increase in gingival cell mitochondria content, with a subsequent increase in reactive oxygen species production (i.e., H2O2), despite a paradoxical reduction in ATP generation. These findings provide an insight into the nature of oxidative stress in oral inflammatory pathologies

Synaptically-Competent Neurons Derived from Canine Embryonic Stem Cells by Lineage Selection with EGF and Noggin

Pluripotent stem cell lines have been generated in several domestic animal species; however, these lines traditionally show poor self-renewal and differentiation. Using canine embryonic stem cell (cESC) lines previously shown to have sufficient self-renewal capacity and potency, we generated and compared canine neural stem cell (cNSC) lines derived by lineage selection with epidermal growth factor (EGF) or Noggin along the neural default differentiation pathway, or by directed differentiation with retinoic acid (RA)-induced floating sphere assay. Lineage selection produced large populations of SOX2+ neural stem/progenitor cell populations and neuronal derivatives while directed differentiation produced few and improper neuronal derivatives. Primary canine neural lines were generated from fetal tissue and used as a positive control for differentiation and electrophysiology. Differentiation of EGF- and Noggin-directed cNSC lines in N2B27 with low-dose growth factors (BDNF/NT-3 or PDGFαα) produced phenotypes equivalent to primary canine neural cells including 3CB2+ radial progenitors, MOSP+ glia restricted precursors, VIM+/GFAP+ astrocytes, and TUBB3+/MAP2+/NFH+/SYN+ neurons. Conversely, induction with RA and neuronal differentiation produced inadequate putative neurons for further study, even though appropriate neuronal gene expression profiles were observed by RT-PCR (including Nestin, TUBB3, PSD95, STX1A, SYNPR, MAP2). Co-culture of cESC-derived neurons with primary canine fetal cells on canine astrocytes was used to test functional maturity of putative neurons. Canine ESC-derived neurons received functional GABAA- and AMPA-receptor mediated synaptic input, but only when co-cultured with primary neurons. This study presents established neural stem/progenitor cell populations and functional neural derivatives in the dog, providing the proof-of-concept required to translate stem cell transplantation strategies into a clinically relevant animal model

Environmentalism, pre-environmentalism, and public policy

In the last decade, thousands of new grassroots groups have formed to oppose environmental pollution on the basis that it endangers their health. These groups have revitalized the environmental movement and enlarged its membership well beyond the middle class. Scientists, however, have been unable to corroborate these groups' claims that exposure to pollutants has caused their diseases. For policy analysts this situation appears to pose a choice between democracy and science. It needn't. Instead of evaluating the grassroots groups from the perspective of science, it is possible to evaluate science from the perspective of environmentalism. This paper argues that environmental epidemiology reflects ‘pre-environmentalist’ assumptions about nature and that new ideas about nature advanced by the environmental movement could change the way scientists collect and interpret data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45449/1/11077_2005_Article_BF01006494.pd

Scientific overview: CSCI – CITAC Annual General Meeting and Young Investigator’s Forum 2012

In 2012, the Annual General Meeting of the Clinical Investigator Trainee Association of Canada – Association des cliniciens-chercheurs en formation du Canada (CITAC – ACCFC) and the Canadian Society of Clinician Investigators (CSCI) was held 19-21 September in Ottawa. Several globally-renowned scientists, including 2012 Friesen International Prize recipient, Dr. Marc Tessier-Lavigne, the CSCI/Royal College Henry Friesen Award recipient, Dr. Morley Hollenberg, and the recipient of the Joe Doupe Young Investigator Award, Dr. Phillip Awadalla, presented on a range of topics on research in basic and translational science in medicine. This year’s CITAC Symposium featured presentations by Dr. Alain Beaudet, Dr. Michael Strong and Dr. Vivek Goel on the Role of Physician Scientists in Public Health and Policy, which was followed by a lively discussion on the role of basic science and clinical research in patient-oriented policy development. This scientific overview highlights the research presented by trainees at both the oral plenary and poster presentation sessions. As at previous meetings, research questions investigated by this year’s trainees span multiple medical disciplines; from basic science to clinical research to medical education. Below is a summary of the presentations showcased at the Young Investigator’s Forum

Pathophysiology and surgical decision-making in central cord syndrome and degenerative cervical myelopathy: correcting the somatotopic fallacy

Our understanding of Central Cord Syndrome (CCS), a form of incomplete spinal cord injury characterized by disproportionate upper extremity weakness, is evolving. Recent advances challenge the traditional somatotopic model of corticospinal tract organization within the spinal cord, suggesting that CCS is likely a diffuse injury rather than focal lesion. Diagnostic criteria for CCS lack consensus, and varied definitions impact patient identification and treatment. Evidence has mounted for early surgery for CCS, although significant variability persists in surgical timing preferences among practitioners. A demographic shift toward an aging population has increased the overlap between CCS and Degenerative Cervical Myelopathy (DCM). Understanding this intersection is crucial for comprehensive patient care. Assessment tools, including quantitative measures and objective evaluations, aid in distinguishing CCS from DCM. The treatment landscape for CCS in the context of pre-existing DCM is complex, requiring careful consideration of pre-existing neurologic injury, patient factors, and injury factors. This review synthesizes emerging evidence, outlines current guidelines in diagnosis and management, and emphasizes the need for ongoing research to refine our understanding and treatment strategies for this evolving patient population

It begins with the right supervisor: Importance of mentorship and clinician-investigator trainee satisfaction levels in Canada

Purpose: Clinician Investigator Trainee Association of Canada/Association des clinicienschercheurs en formation du Canada (CITAC/ACCFC) represents the interests of clinician-investigator (CI) trainees across Canada. To better advocate for the successful training of CI trainees in Canada, CITAC/ACCFC conducted a survey to assess satisfaction with their training and to find what factors were most associated with satisfaction level. Methods: A nominal scale-based psychometric survey was conducted online in 2009 on CI trainees in Canada (including MD/MSc, MD/PhD, or CIP/SSP). One hundred fifteen out of a target population of approximately 350-400 responded. Survey respondents were asked to rate their level of satisfaction in four areas: 1) quality of training, 2) financial support, 3) mentorship satisfaction and 4) program structure. Ratings in these four areas were also combined to produce a measure of overall satisfaction. Results: At least half of the respondents were \u27completely satisfied\u27 in each of the four categories other than mentorship. While 98% of respondents considered mentorship as important to their success, 62% expressed some level of dissatisfaction with the level of mentorship received. Moreover, increased levels of mentorship were strongly associated with increased levels of overall satisfaction. Conclusion: The discrepancy between CI trainees\u27 perceived importance of mentorship and the level of satisfaction in mentorship received reveals a strategic area where CI training should be improved. Recognizing that good mentorship in a CI training program ofien begins with one\u27s research supervisor, the CITAC/ACCFC has compiled six specific recommendations for finding a good supervisor. © 2013 CIM