title: Distinct gene expression profiles directed by the isoforms of the transcription factor neuron-restrictive silencer factor in human SK-N-AS neuroblastoma cells

authors: Gillies, Stuart G.

subjects: NRSF

abstract: Neuron-restrictive silencer factor (NRSF) and its isoforms are differentially regulated in rodent models of self-sustaining status epilepticus (SSSE). NRSF isoforms regulate genes associated with SSSE, including the proconvulsant tachykinins, brain-derived neurotrophic factor and multiple ion channels. NRSF isoforms may direct distinct gene expression patterns during SSSE, and the ratio of each isoform may be a causative factor in traumatic damage to the central nervous system. Here, we analysed global gene expression changes by microarray in human SK-N-AS neuroblastoma cells following the over-expression of NRSF and a truncated isoform, HZ4. We used bioinformatics software to analyse the microarray dataset and correlated these data with epilepsy candidate gene pathways. Findings were validated by reverse transcriptase-polymerase chain reaction. We demonstrated that NRSF and HZ4 direct overlapping as well as distinct gene expression patterns, and that they differentially modulated gene expression patterns associated with epilepsy. Finally, we revealed that NRSF gene expression may be modulated by the anticonvulsant, phenytoin. We have interpreted our data to reflect altered gene expression directed by NRSF that might be relevant for SSSE.

text: Distinct gene expression profiles directed by the isoforms of the transcription factor neuron-restrictive silencer factor in human SK-N-AS neuroblastoma cells Neuron-restrictive silencer factor (NRSF) and its isoforms are differentially regulated in rodent models of self-sustaining status epilepticus (SSSE). NRSF isoforms regulate genes associated with SSSE, including the proconvulsant tachykinins, brain-derived neurotrophic factor and multiple ion channels. NRSF isoforms may direct distinct gene expression patterns during SSSE, and the ratio of each isoform may be a causative factor in traumatic damage to the central nervous system. Here, we analysed global gene expression changes by microarray in human SK-N-AS neuroblastoma cells following the over-expression of NRSF and a truncated isoform, HZ4. We used bioinformatics software to analyse the microarray dataset and correlated these data with epilepsy candidate gene pathways. Findings were validated by reverse transcriptase-polymerase chain reaction. We demonstrated that NRSF and HZ4 direct overlapping as well as distinct gene expression patterns, and that they differentially modulated gene expression patterns associated with epilepsy. Finally, we revealed that NRSF gene expression may be modulated by the anticonvulsant, phenytoin. We have interpreted our data to reflect altered gene expression directed by NRSF that might be relevant for SSSE.

year: 2011

title: Measuring the bulk impedance of brain tissue in vitro

authors: Wilson, Marcus T.

abstract: Theoretical and numerical models of brain activity suggest a link between seizures and electrical connectivity. We have therefore been motivated to measure electrical conductivity in brain tissue. Such measurements in vitro are difficult; it is necessary to use a conductive inorganic salt solution, artificial cerebrospinal fluid (ACSF), to keep the tissue alive. We have attempted to provide a robust method to make such measurements. Mouse brain tissue was sliced (400 μm) using established methods. Half the slices were placed in standard ACSF; half were placed in ACSF devoid of magnesium ions. The latter case promotes seizure activity. Electrical activity was measured with a tungsten electrode at various places on the slices. Sixty-nine samples of cortex (2 mm × 2 mm) were cut with a razor. Their areas were measured with a calibrated microscope. Each sample was placed between two flat Ag/AgCl electrodes in a Perspex sandwich. Excess ACSF was removed with filter paper. The impedance was measured at 25°C from 20 Hz to 2 MHz with an Agilent E4980A four-point impedance meter in a shielded room, using a low current. Between 1 kHz and 100 kHz the conductivity was approximately 0.2 S m⁻¹; outside this range dispersion occurred. Samples prepared in the magnesium-free ACSF had a conductivity about 10% lower. The Cole-Cole model of conductivity was fitted. There were few significant differences between the parameters for the different groups measured.

text: Measuring the bulk impedance of brain tissue in vitro Theoretical and numerical models of brain activity suggest a link between seizures and electrical connectivity. We have therefore been motivated to measure electrical conductivity in brain tissue. Such measurements in vitro are difficult; it is necessary to use a conductive inorganic salt solution, artificial cerebrospinal fluid (ACSF), to keep the tissue alive. We have attempted to provide a robust method to make such measurements. Mouse brain tissue was sliced (400 μm) using established methods. Half the slices were placed in standard ACSF; half were placed in ACSF devoid of magnesium ions. The latter case promotes seizure activity. Electrical activity was measured with a tungsten electrode at various places on the slices. Sixty-nine samples of cortex (2 mm × 2 mm) were cut with a razor. Their areas were measured with a calibrated microscope. Each sample was placed between two flat Ag/AgCl electrodes in a Perspex sandwich. Excess ACSF was removed with filter paper. The impedance was measured at 25°C from 20 Hz to 2 MHz with an Agilent E4980A four-point impedance meter in a shielded room, using a low current. Between 1 kHz and 100 kHz the conductivity was approximately 0.2 S m⁻¹; outside this range dispersion occurred. Samples prepared in the magnesium-free ACSF had a conductivity about 10% lower. The Cole-Cole model of conductivity was fitted. There were few significant differences between the parameters for the different groups measured.

year: 2015

title: Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan Canada: A comparative study

authors: Green, Jane Alison

subjects: Indigenous

abstract: For more than two decades, components of Māori knowledges in the form of Māori words and concepts have been part of health policy in Aotearoa New Zealand. Health policy that engages Māori words and concepts resonates with Māori community values and aspirations and is thought to contribute to the revitalisation of Māori knowledges. Absent from the literature is an examination of this phenomenon; specifically, the socio-political factors that facilitate and limit the engagement of Māori knowledges with health policy. Of the four settler states, only in Aotearoa New Zealand are the knowledges of the Indigenous peoples engaged with health policy. In Saskatchewan, Canada, the First Nations and Métis peoples have engaged their knowledges with federal and provincially funded health programmes and services but not health policy. This study adopts a two-country comparative policy framework to investigate and theorise the historical and contemporary socio-political factors associated with the engagement of Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan, Canada. An adaption is made to the Kaupapa Māori approach so that the complexities of a two-country case study approach are addressed and engagement in health policy as a strategy for knowledge revitalisation is theorised. The study also takes a path less travelled which is to investigate the impact that engagement with health policy has upon the intangible or the ontological aspects of Māori knowledges. Māori describe their knowledges as comprised of tangible and intangible elements, both of which are important. Another adaption is made to the Kaupapa Māori theoretical approach which is to add speculative inquiry. The study argues that speculative inquiry in the form of contemplative, analytical, relational and viscerally aware practices are commonplace in Māori communities. Adding speculative inquiry to an already rich theoretical body that is Kaupapa Māori research provides an opening for other Kaupapa Māori researchers to expand non-empirical inquiry. The study concludes that government policies have had a decimating effect upon Māori, First Nations and Métis knowledges. Moreover, recent reports from commissions and inquiries indicate these knowledges and associated languages continue to decline for a number of reasons, including the impact of contemporary government policies. Health policy, this study asserts, is an uncertain site from which to revitalise Māori, First Nations and Métis knowledges.

text: Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan Canada: A comparative study For more than two decades, components of Māori knowledges in the form of Māori words and concepts have been part of health policy in Aotearoa New Zealand. Health policy that engages Māori words and concepts resonates with Māori community values and aspirations and is thought to contribute to the revitalisation of Māori knowledges. Absent from the literature is an examination of this phenomenon; specifically, the socio-political factors that facilitate and limit the engagement of Māori knowledges with health policy. Of the four settler states, only in Aotearoa New Zealand are the knowledges of the Indigenous peoples engaged with health policy. In Saskatchewan, Canada, the First Nations and Métis peoples have engaged their knowledges with federal and provincially funded health programmes and services but not health policy. This study adopts a two-country comparative policy framework to investigate and theorise the historical and contemporary socio-political factors associated with the engagement of Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan, Canada. An adaption is made to the Kaupapa Māori approach so that the complexities of a two-country case study approach are addressed and engagement in health policy as a strategy for knowledge revitalisation is theorised. The study also takes a path less travelled which is to investigate the impact that engagement with health policy has upon the intangible or the ontological aspects of Māori knowledges. Māori describe their knowledges as comprised of tangible and intangible elements, both of which are important. Another adaption is made to the Kaupapa Māori theoretical approach which is to add speculative inquiry. The study argues that speculative inquiry in the form of contemplative, analytical, relational and viscerally aware practices are commonplace in Māori communities. Adding speculative inquiry to an already rich theoretical body that is Kaupapa Māori research provides an opening for other Kaupapa Māori researchers to expand non-empirical inquiry. The study concludes that government policies have had a decimating effect upon Māori, First Nations and Métis knowledges. Moreover, recent reports from commissions and inquiries indicate these knowledges and associated languages continue to decline for a number of reasons, including the impact of contemporary government policies. Health policy, this study asserts, is an uncertain site from which to revitalise Māori, First Nations and Métis knowledges.

year: 2018