title: The Assessment of Vitamin D, Antimicrobial Peptides and Procalcitonin in Bronchiectasis

authors: Gartner, Sarah Nicole

subjects: vitamin D

abstract: My research investigated the distribution of antimicrobial peptides (cathelicidin and β-defensin 2), vitamin D and the inflammatory marker procalcitonin, between systemic and localised respiratory levels in stable bronchiectasis patients. Bronchiectasis is a localised chronic lung disease that is characterised by acute reoccurring lower tract respiratory infections. Non-cystic fibrosis bronchiectasis patient serum and sputum samples were collected as part of an ongoing clinical trial. This trial is investigating the usefulness of Tiotropium for the treatment of bronchiectasis. 

Antimicrobial peptides are a fundamental component of the innate immune system. The innate immune system is vital in providing the first line of defence against pathogens. At epithelia sites this is more so, as cells are often in direct contact with the environment. Both cathelicidin and β-defensin 2 expression has been found to be upregulated by the active vitamin D metabolite, 1,25-dihydroxyvitamin D. This research also aimed to determine if vitamin D deficiency is prevalent in bronchiectasis, and how these levels correspond with cathelicidin and hBD-2. Lastly, whether procalcitonin, a known inflammatory marker of bacterial infections is a suitable biomarker for bronchiectasis. Other inflammatory markers have been shown to be consistently elevated in stable bronchiectasis patients. 

The use of commercial ELISA kits demonstrated the notion of systemic levels not being representative of localised levels. Both of the antimicrobial peptides, cathelicidin and β-defensin 2, show elevated sputum levels consistent with bronchiectasis being a localised condition. Contrastingly, vitamin D metabolites are found to be lower in the airways. This is predicted to be due to the majority of vitamin D metabolites being protein bound in circulation, thereby affecting their tissue distribution. Stable bronchiectasis patients do not have persistently elevated serum procalcitonin levels but procalcitonin levels are significantly higher in the sputum.  

Our findings report that suboptimal vitamin D levels, but not vitamin D deficiency, were prevalent in stable bronchiectasis patients. No correlations were found between 25-hydroxyvitamin D and antimicrobial peptide concentrations, consistent with other studies findings. However, localised levels of the active form, 1,25-dihydroxyvitamin D, were correlated with localised cathelicidin (CAMP) levels but not β-defensin 2. 

Future work should focus on the hormonal form, 1,25-dihydroxyvitamin D, if an in vivo association with antimicrobial peptides is to be found. A number of factors can influence vitamin D bioavailability, including, known single nucleotide polymorphisms in the vitamin D receptor and vitamin D binding protein.

text: The Assessment of Vitamin D, Antimicrobial Peptides and Procalcitonin in Bronchiectasis My research investigated the distribution of antimicrobial peptides (cathelicidin and β-defensin 2), vitamin D and the inflammatory marker procalcitonin, between systemic and localised respiratory levels in stable bronchiectasis patients. Bronchiectasis is a localised chronic lung disease that is characterised by acute reoccurring lower tract respiratory infections. Non-cystic fibrosis bronchiectasis patient serum and sputum samples were collected as part of an ongoing clinical trial. This trial is investigating the usefulness of Tiotropium for the treatment of bronchiectasis. 

Antimicrobial peptides are a fundamental component of the innate immune system. The innate immune system is vital in providing the first line of defence against pathogens. At epithelia sites this is more so, as cells are often in direct contact with the environment. Both cathelicidin and β-defensin 2 expression has been found to be upregulated by the active vitamin D metabolite, 1,25-dihydroxyvitamin D. This research also aimed to determine if vitamin D deficiency is prevalent in bronchiectasis, and how these levels correspond with cathelicidin and hBD-2. Lastly, whether procalcitonin, a known inflammatory marker of bacterial infections is a suitable biomarker for bronchiectasis. Other inflammatory markers have been shown to be consistently elevated in stable bronchiectasis patients. 

The use of commercial ELISA kits demonstrated the notion of systemic levels not being representative of localised levels. Both of the antimicrobial peptides, cathelicidin and β-defensin 2, show elevated sputum levels consistent with bronchiectasis being a localised condition. Contrastingly, vitamin D metabolites are found to be lower in the airways. This is predicted to be due to the majority of vitamin D metabolites being protein bound in circulation, thereby affecting their tissue distribution. Stable bronchiectasis patients do not have persistently elevated serum procalcitonin levels but procalcitonin levels are significantly higher in the sputum.  

Our findings report that suboptimal vitamin D levels, but not vitamin D deficiency, were prevalent in stable bronchiectasis patients. No correlations were found between 25-hydroxyvitamin D and antimicrobial peptide concentrations, consistent with other studies findings. However, localised levels of the active form, 1,25-dihydroxyvitamin D, were correlated with localised cathelicidin (CAMP) levels but not β-defensin 2. 

Future work should focus on the hormonal form, 1,25-dihydroxyvitamin D, if an in vivo association with antimicrobial peptides is to be found. A number of factors can influence vitamin D bioavailability, including, known single nucleotide polymorphisms in the vitamin D receptor and vitamin D binding protein.

year: 2014

title: The Sediment Dynamics of Ahuriri Estuary, Napier, New Zealand

authors: Eyre, Tracey Michelle

subjects: Ahuriri

abstract: Ahuriri Estuary is a shallow, microtidal estuary located in Hawke's Bay, New Zealand. Sediment transport pathways and areas of potential erosion and accretion of Ahuriri Estuary are identified to enhance the understanding of the fate of contaminants entering the estuary and to provide a basis for future large-scale modelling applications. Fine sediments have a high adsorption capacity for heavy metals and nutrients, which may result in the accumulation of contaminants in estuarine environments. Extensive land claim of previously inundated areas uplifted by the 1931 Napier earthquake for industrial, urban and agricultural expansion has led to an increase in heavy metal and nutrient runoff into the estuary. Characterising the hydrodynamics and sediment transport of the estuary is imperative for the prediction and mitigation of sedimentation and contaminant accumulation.
A combination of hydrodynamic and sediment transport modelling using the DHI MIKE 21 suite was used to run a series of scenarios of sediment release into the estuary and subsequent dispersal. The MIKE 21 Flow model was calibrated and validated using field data from two field deployments conducted during a spring and neap tide. The hydrodynamic model predicted current direction and velocity patterns in concurrence with measured data. Residual circulation patterns in Ahuriri Estuary were ebb-dominated, indicating a likely net downstream movement in sediment. Flow was highly channelised within the middle - lower estuary, with a low energy regime in the upper estuary. This suggested that sediment introduced into the estuary from the Taipo Stream is likely to be flushed from the estuary if it reached the middle estuary. However, flow velocities and lack of residual currents in the upper estuary resulted in a large proportion of sediment introduced during storm runoff settling out of suspension, resulting in net deposition in close proximity to the source. 
Sediment grain-size and consequently the settling velocity were found to be the main contributing factor to sediment dispersal. Fine silts were found to be transported the furthest downstream with a large proportion being transported from the estuary mouth and the model domain, respectively. A large proportion of coarser silts and fine sands were found to settle out of suspension in close proximity to the sediment source. An increased settling velocity resulted in an increased influence of the simulation conditions at the time of sediment release, as it was the initial transport of coarser grain-sizes which determined their ultimate depositional location. Sediment deposition was greatest in close proximity to the source and in upper intertidal regions, which are a major sink for suspended sediments due to their sheltered nature. This was correlated with greater organic carbon content and finer grain-sizes in these areas, suggesting a depositional environment. A general trend of fining of grain-size from high energy to low energy environments was identified. In these areas, sediment reworking due to tidal action and wave-related processes was limited.

text: The Sediment Dynamics of Ahuriri Estuary, Napier, New Zealand Ahuriri Estuary is a shallow, microtidal estuary located in Hawke's Bay, New Zealand. Sediment transport pathways and areas of potential erosion and accretion of Ahuriri Estuary are identified to enhance the understanding of the fate of contaminants entering the estuary and to provide a basis for future large-scale modelling applications. Fine sediments have a high adsorption capacity for heavy metals and nutrients, which may result in the accumulation of contaminants in estuarine environments. Extensive land claim of previously inundated areas uplifted by the 1931 Napier earthquake for industrial, urban and agricultural expansion has led to an increase in heavy metal and nutrient runoff into the estuary. Characterising the hydrodynamics and sediment transport of the estuary is imperative for the prediction and mitigation of sedimentation and contaminant accumulation.
A combination of hydrodynamic and sediment transport modelling using the DHI MIKE 21 suite was used to run a series of scenarios of sediment release into the estuary and subsequent dispersal. The MIKE 21 Flow model was calibrated and validated using field data from two field deployments conducted during a spring and neap tide. The hydrodynamic model predicted current direction and velocity patterns in concurrence with measured data. Residual circulation patterns in Ahuriri Estuary were ebb-dominated, indicating a likely net downstream movement in sediment. Flow was highly channelised within the middle - lower estuary, with a low energy regime in the upper estuary. This suggested that sediment introduced into the estuary from the Taipo Stream is likely to be flushed from the estuary if it reached the middle estuary. However, flow velocities and lack of residual currents in the upper estuary resulted in a large proportion of sediment introduced during storm runoff settling out of suspension, resulting in net deposition in close proximity to the source. 
Sediment grain-size and consequently the settling velocity were found to be the main contributing factor to sediment dispersal. Fine silts were found to be transported the furthest downstream with a large proportion being transported from the estuary mouth and the model domain, respectively. A large proportion of coarser silts and fine sands were found to settle out of suspension in close proximity to the sediment source. An increased settling velocity resulted in an increased influence of the simulation conditions at the time of sediment release, as it was the initial transport of coarser grain-sizes which determined their ultimate depositional location. Sediment deposition was greatest in close proximity to the source and in upper intertidal regions, which are a major sink for suspended sediments due to their sheltered nature. This was correlated with greater organic carbon content and finer grain-sizes in these areas, suggesting a depositional environment. A general trend of fining of grain-size from high energy to low energy environments was identified. In these areas, sediment reworking due to tidal action and wave-related processes was limited.

year: 2009

title: Positioning historical trauma theory within Aotearoa New Zealand

authors: Pihama, Leonie

abstract: This article explores the relevance of historical trauma theory for Mäori research. In exploring the impact of historical trauma upon Mäori it has become clear that the terminology associated with historical trauma theory is considered controversial in Aotearoa New Zealand. As such, this article provides an overview of key defi nitions relevant to historical trauma and explores these in relation to recent reporting related to the use of the terms “holocaust” and “genocide” in the context of colonization in Aotearoa New Zealand. It is argued that in order to engage fully with the impacts of colonization on Mäori wellbeing we must articulate fully the impact of historical trauma events and the contribution of those events to the negative health disparities experienced by many of our whänau (extended family), hapü (sub- tribes) and iwi (tribes).

text: Positioning historical trauma theory within Aotearoa New Zealand This article explores the relevance of historical trauma theory for Mäori research. In exploring the impact of historical trauma upon Mäori it has become clear that the terminology associated with historical trauma theory is considered controversial in Aotearoa New Zealand. As such, this article provides an overview of key defi nitions relevant to historical trauma and explores these in relation to recent reporting related to the use of the terms “holocaust” and “genocide” in the context of colonization in Aotearoa New Zealand. It is argued that in order to engage fully with the impacts of colonization on Mäori wellbeing we must articulate fully the impact of historical trauma events and the contribution of those events to the negative health disparities experienced by many of our whänau (extended family), hapü (sub- tribes) and iwi (tribes).

year: 2014