title: Aconitine induces prolonged seizure-like events in rat neocortical brain slices

authors: Voss, Logan J.

subjects: cerebral cortex

abstract: Aconitine effects on the hippocampal slice preparation have been well documented and include acute inhibitory and prolonged excitatory effects. To date, the effect of aconitine on neocortical activity has not been investigated. The aim of this study was to characterise the acute and long term effects of aconitine on cortical local field potential activity. Neocortical slices from juvenile Sprague–Dawley rats were perfused at room temperature with aconitine in normal artificial cerebrospinal fluid (aCSF) (n = 10). Spontaneous local field potential activity was recorded from the somatosensory cortex. The calcium dependence of aconitine-induced activity was investigated using low-calcium aCSF (n = 8). To isolate sodium and N-methyl-d-aspartate (NMDA) channel effects, phenytoin (n = 4) and 2-amino-5-phosphono-pentanoic acid (APV) (n = 6) were co-administered with aconitine, respectively. Aconitine consistently induced a dramatic increase in population “spike” activity after prolonged (89.5 ± 36.6 min) application in normal aCSF. This activity surge was eliminated in low-calcium aCSF and when aconitine was co-administered with phenytoin and APV. The acute effects of aconitine application were variable and included an increase in the frequency of population spikes, appearance of oscillatory seizure-like activity and prolonged bursts of multiunit activity. No acute inhibitory effects were observed. Aconitine has acute and prolonged excitatory effects on neocortical activity. The latter is effected by calcium-dependent mechanisms, in keeping with known effects of aconitine on hippocampal slices. Both sodium and NMDA channels are involved in mediating the calcium-dependent aconitine effects.

text: Aconitine induces prolonged seizure-like events in rat neocortical brain slices Aconitine effects on the hippocampal slice preparation have been well documented and include acute inhibitory and prolonged excitatory effects. To date, the effect of aconitine on neocortical activity has not been investigated. The aim of this study was to characterise the acute and long term effects of aconitine on cortical local field potential activity. Neocortical slices from juvenile Sprague–Dawley rats were perfused at room temperature with aconitine in normal artificial cerebrospinal fluid (aCSF) (n = 10). Spontaneous local field potential activity was recorded from the somatosensory cortex. The calcium dependence of aconitine-induced activity was investigated using low-calcium aCSF (n = 8). To isolate sodium and N-methyl-d-aspartate (NMDA) channel effects, phenytoin (n = 4) and 2-amino-5-phosphono-pentanoic acid (APV) (n = 6) were co-administered with aconitine, respectively. Aconitine consistently induced a dramatic increase in population “spike” activity after prolonged (89.5 ± 36.6 min) application in normal aCSF. This activity surge was eliminated in low-calcium aCSF and when aconitine was co-administered with phenytoin and APV. The acute effects of aconitine application were variable and included an increase in the frequency of population spikes, appearance of oscillatory seizure-like activity and prolonged bursts of multiunit activity. No acute inhibitory effects were observed. Aconitine has acute and prolonged excitatory effects on neocortical activity. The latter is effected by calcium-dependent mechanisms, in keeping with known effects of aconitine on hippocampal slices. Both sodium and NMDA channels are involved in mediating the calcium-dependent aconitine effects.

year: 2008

title: The Nature of the Relationships between Social Networks, Interpersonal Trust, Management Support, and Knowledge Sharing

authors: Al Saifi, Said Abdullah

subjects: Social networks

abstract: Purpose – Past research has shown that, by implementing knowledge sharing, an organisation can maintain its long-term competitive advantage. Hence, this research will explore the nature of the relationships between social networks, interpersonal trust, management support, and knowledge sharing. 

Methodology/approach – In order to achieve the above purpose, semi-structured interviews were used to gather qualitative data. Interviewee participants included top and middle managers and frontline employees. The total number of participants included in the research was 25, equally representing five companies. The core business of all the companies was large-scale manufacturing. A grounded theory approach was used to analyse the data, augmented by the computer-assisted qualitative data analysis software, Nvivo.

Findings – The results reveal that social networks facilitate knowledge sharing in diverse ways. These ways are: the use of multiple communication styles, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. In addition, the data from the interviews suggests that, through various factors, the level of interpersonal trust, influences the extent to which employees are willing to share knowledge. These factors are organisational, relational, and individual factors. Furthermore, this study shows that both middle and top managers can play significant roles in facilitating knowledge sharing between employees. These roles are: encouragement of participation in decision-making, provision of recognition, breaking down of barriers, building up of teams, providing training or assigning others to do training, encouragement of training, communication, learning, putting knowledge into practice in the form of processes, and movement of employees.

Research contributions – Six models were developed from the qualitative analysis of the field data. The brainstorming and problem solving model identifies various steps for brainstorming and problem solving which influence social networks and knowledge sharing. The model of learning and teaching explains how social networks can be built based on the receivers’ levels of knowledge, namely, the novice, competent, expert, and proficient levels. The model of factors influencing social networks and knowledge sharing illustrates various factors. These are: using multiple communication strategies, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. The model of factors influencing interpersonal trust describes three factors for achieving such trust: organisational, relational, and individual factors. This model also elaborates on three factors that negatively influence interpersonal trust. These are division between departments, team conflict, and a sense of vulnerability. 

The model of the role of management teams in encouraging participation in decision-making elaborates on levels of decision-making among employees and the way in which knowledge flows between top and middle management and frontline employees. The integrative model deciphers the relationships between social networks, interpersonal trust, management support, openness, and knowledge sharing. In addition, the relationships between each area of emphasis and knowledge sharing are included in the model. Based on this model, a survey questionnaire was developed.

These models provide new insights into the relationships between social networks, interpersonal trust, management support, and knowledge sharing. By applying these models to appropriate field situations, both practitioners and academics may be able to improve current practices relating to how knowledge is shared and evolves within organisations.

text: The Nature of the Relationships between Social Networks, Interpersonal Trust, Management Support, and Knowledge Sharing Purpose – Past research has shown that, by implementing knowledge sharing, an organisation can maintain its long-term competitive advantage. Hence, this research will explore the nature of the relationships between social networks, interpersonal trust, management support, and knowledge sharing. 

Methodology/approach – In order to achieve the above purpose, semi-structured interviews were used to gather qualitative data. Interviewee participants included top and middle managers and frontline employees. The total number of participants included in the research was 25, equally representing five companies. The core business of all the companies was large-scale manufacturing. A grounded theory approach was used to analyse the data, augmented by the computer-assisted qualitative data analysis software, Nvivo.

Findings – The results reveal that social networks facilitate knowledge sharing in diverse ways. These ways are: the use of multiple communication styles, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. In addition, the data from the interviews suggests that, through various factors, the level of interpersonal trust, influences the extent to which employees are willing to share knowledge. These factors are organisational, relational, and individual factors. Furthermore, this study shows that both middle and top managers can play significant roles in facilitating knowledge sharing between employees. These roles are: encouragement of participation in decision-making, provision of recognition, breaking down of barriers, building up of teams, providing training or assigning others to do training, encouragement of training, communication, learning, putting knowledge into practice in the form of processes, and movement of employees.

Research contributions – Six models were developed from the qualitative analysis of the field data. The brainstorming and problem solving model identifies various steps for brainstorming and problem solving which influence social networks and knowledge sharing. The model of learning and teaching explains how social networks can be built based on the receivers’ levels of knowledge, namely, the novice, competent, expert, and proficient levels. The model of factors influencing social networks and knowledge sharing illustrates various factors. These are: using multiple communication strategies, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. The model of factors influencing interpersonal trust describes three factors for achieving such trust: organisational, relational, and individual factors. This model also elaborates on three factors that negatively influence interpersonal trust. These are division between departments, team conflict, and a sense of vulnerability. 

The model of the role of management teams in encouraging participation in decision-making elaborates on levels of decision-making among employees and the way in which knowledge flows between top and middle management and frontline employees. The integrative model deciphers the relationships between social networks, interpersonal trust, management support, openness, and knowledge sharing. In addition, the relationships between each area of emphasis and knowledge sharing are included in the model. Based on this model, a survey questionnaire was developed.

These models provide new insights into the relationships between social networks, interpersonal trust, management support, and knowledge sharing. By applying these models to appropriate field situations, both practitioners and academics may be able to improve current practices relating to how knowledge is shared and evolves within organisations.

year: 2014

title: Management of patients with early stage lung cancer - why do some patients not receive treatment with curative intent?

authors: Lawrenson, Ross

subjects: Lung cancer

abstract: BACKGROUNDS: This study aims to understand the factors that influence whether patients receive potentially curative treatment for early stage lung cancer. A key question was whether indigenous Māori patients were less likely to receive treatment. 
METHODS: Patients included those diagnosed with early stage lung cancer in 2011-2018 and resident in the New Zealand Midland Cancer Network region. Logistic regression model was used to estimate the odds ratios of having curative surgery/ treatment. The Kaplan Meier method was used to examine the all-cause survival and Cox proportional hazard model was used to estimate the hazard ratio of death. 
RESULTS: In total 419/583 (71.9%) of patients with Stage I and II disease were treated with curative intent - 272 (46.7%) patients had curative surgery. Patients not receiving potentially curative treatment were older, were less likely to have non-small cell lung cancer (NSCLC), had poorer lung function and were more likely to have an ECOG performance status of 2+. Current smokers were less likely to be treated with surgery and more likely to receive treatment with radiotherapy and chemotherapy. Those who were treated with surgery had a 2-year survival of 87.8% (95% CI: 83.8-91.8%) and 5-year survival of 69.6% (95% CI: 63.2-76.0%). Stereotactic ablative body radiotherapy (SABR) has equivalent effect on survival compared to curative surgery (hazard ratio: 0.77, 95% CI: 0.37-1.61). After adjustment we could find no difference in treatment and survival between Māori and non-Māori. 
CONCLUSIONS: The majority of patients with stage I and II lung cancer are managed with potentially curative treatment - mainly surgery and increasingly with SABR. The outcomes of those being diagnosed with stage I and II disease and receiving treatment is positive with 70% surviving 5 years.

text: Management of patients with early stage lung cancer - why do some patients not receive treatment with curative intent? BACKGROUNDS: This study aims to understand the factors that influence whether patients receive potentially curative treatment for early stage lung cancer. A key question was whether indigenous Māori patients were less likely to receive treatment. 
METHODS: Patients included those diagnosed with early stage lung cancer in 2011-2018 and resident in the New Zealand Midland Cancer Network region. Logistic regression model was used to estimate the odds ratios of having curative surgery/ treatment. The Kaplan Meier method was used to examine the all-cause survival and Cox proportional hazard model was used to estimate the hazard ratio of death. 
RESULTS: In total 419/583 (71.9%) of patients with Stage I and II disease were treated with curative intent - 272 (46.7%) patients had curative surgery. Patients not receiving potentially curative treatment were older, were less likely to have non-small cell lung cancer (NSCLC), had poorer lung function and were more likely to have an ECOG performance status of 2+. Current smokers were less likely to be treated with surgery and more likely to receive treatment with radiotherapy and chemotherapy. Those who were treated with surgery had a 2-year survival of 87.8% (95% CI: 83.8-91.8%) and 5-year survival of 69.6% (95% CI: 63.2-76.0%). Stereotactic ablative body radiotherapy (SABR) has equivalent effect on survival compared to curative surgery (hazard ratio: 0.77, 95% CI: 0.37-1.61). After adjustment we could find no difference in treatment and survival between Māori and non-Māori. 
CONCLUSIONS: The majority of patients with stage I and II lung cancer are managed with potentially curative treatment - mainly surgery and increasingly with SABR. The outcomes of those being diagnosed with stage I and II disease and receiving treatment is positive with 70% surviving 5 years.

year: 2020