title: Abundance and Function of Multiple Haemoglobin Isomorphs from Rainbow Trout (Oncorhynchus mykiss)

authors: Tempero, Grant Wayne

subjects: Hemoglobin

abstract: Haemoglobins perform the vital physiological function of transporting oxygen from the external environment to the tissues. Poikilothermic rainbow trout (Oncorhynchus mykiss = Salmo gairdneri = S. irideus) produce multiple forms of haemoglobin that respond differently to varying environmental and physiological conditions. However, the timescale and physiology of these changes are not known. Changes in isomorph abundance may potentially originate from the production of new isomorphs in already circulating erythrocytes. Alternatively, new isomorphs may be produced through the reassembly of extant haemoglobin subunits. The final hypothesis is that changes in isomorph abundance occur through the production of new erythrocytes with red blood cells ‘pre-programmed’ to produce a particular set of haemoglobins. Changes originating from production of new erythrocytes would require longer periods of time before being detectable; weeks to months depending on the temperature regime. To test this, paired groups of rainbow trout were subjected to either 10ºC or 20ºC for 5, 7, 14, 21 and 28 days. A total of 14 isomorphs were observed after the haemolysate was separated using cellulose acetate electrophoresis. However, no detectable differences in isomorph abundance were found between treatment groups. In a follow-up experiment, anaemia was induced in rainbow trout to stimulate the production of new erythrocytes. The trout were then held at either 10ºC or 20ºC for 21 days. This resulted in relative increases in the abundance of anodal haemoglobin isomorphs in the 20ºC acclimated group and a corresponding decrease in cathodal haemoglobin isomorphs. To further confirm that changes in abundance were occurring through the production of new erythrocytes, separation of erythrocytes into age classes was undertaken to compare the isomorphs present in mature erythrocytes with those from erythrocytes produced under amended temperature regimes. Using Percoll density gradients, red blood cells from anaemia-induced trout acclimated to either 10ºC or 20ºC were enriched into mature and young erythrocyte fractions. Further significant differences in abundance were found between both anodal and cathodal isomorphs when compared between treatment groups. From these results it was concluded that changes in haemoglobin isomorph abundance originated from the production of new erythrocytes. Cellulose acetate gel electrophoresis was carried out on seven haemoglobin fractions that had undergone prior separation from whole haemolysate by Fast Protein Liquid Chromatography. Each haemoglobin fraction was found to be composed of two isomorphs for a total of 14 haemoglobin isomorphs. The oxygen binding properties of each fraction was examined under varying conditions of temperature, pH, ATP and chloride concentrations. Cathodal functional groups HbI to HbIII were found to be insensitive to temperature, pH, chloride and the organic phosphate ATP. In contrast, the anodal fractions (HbIV to HbVII) all responded to pH and temperature changes, while HbVI and HbVII responded to ATP. However, no fraction responded to increased chloride concentrations. These results suggest that different varieties of rainbow trout may produce different forms of haemoglobin as part of an adaptive response to local environmental conditions, leading to variation in the functional properties of some of the less abundant functional groups such as HbIII. Despite the theory that cathodal haemoglobins function as emergency back-up supplies of oxygen being proposed more than thirty years ago, no published information can be found for it being tested in the laboratory. Two groups of anaemia-induced rainbow trout were placed in a divided annular flume for 24 days. The high activity group was subjected to a forced swimming speed of 2.5 body lengths (B.L.) s-1 for 6 h d-1. When not undergoing forced exercise the treatment group were maintained at the same speed as the low activity group of 0.5 B.L. s-1. Significant differences in haemoglobin isomorph abundance were present between the initial samples taken at the time of anaemia induction and high and low activity groups. However, only the C4 isomorph demonstrated a significant difference between high and low activity groups. When total anodal and cathodal isomorphs were compared between initial state, high activity and low activity groups, no differences were present. These data suggest that the induction of anaemia had an effect on the composition of the isomorphs but no physiological effect on oxygen delivery. In addition, the swimming velocity of 2.5 B.L. s-1 employed for the high activity group may have been an insufficient stimulus to induce changes in isomorph abundance. It is concluded that changes in haemoglobin isomorph abundance occur in response to chronic changes in the environment. Increases in the abundance of anodal isoforms in response to increasing temperature allows for increased delivery of oxygen to tissues undergoing increases in metabolic activity associated with higher temperatures. The multiple haemoglobin isomorphs of rainbow trout provide an increased efficiency in delivery of oxygen to tissues under varying metabolic conditions of pH, temperature and oxygen saturation. The cathodal and anodal haemoglobin functional groups of rainbow trout exhibit different oxygen affinities in response to temperature, pH and ATP concentration but not to physiologically realistic chloride concentrations. The oxygen binding properties of the isomorphs within the cathodal and anodal functional groups are broadly similar. However, differences in responses by the anodal functional groups to NTPs may exist. An examination of the hypothesis that cathodal haemoglobins act as reserve oxygen delivery sources under prolonged activity produced no significant results. However, this hypothesis still remains viable and needs to be tested under different experimental conditions. This work provides a basis for further research into the adaptive abilities of rainbow trout. The selection of rainbow trout which better adapt to wide ranges of environmental conditions would allow for targeted introduction by fisheries managers to aquatic systems previously not considered optimal for trout growth thereby expanding the fishery.

text: Abundance and Function of Multiple Haemoglobin Isomorphs from Rainbow Trout (Oncorhynchus mykiss) Haemoglobins perform the vital physiological function of transporting oxygen from the external environment to the tissues. Poikilothermic rainbow trout (Oncorhynchus mykiss = Salmo gairdneri = S. irideus) produce multiple forms of haemoglobin that respond differently to varying environmental and physiological conditions. However, the timescale and physiology of these changes are not known. Changes in isomorph abundance may potentially originate from the production of new isomorphs in already circulating erythrocytes. Alternatively, new isomorphs may be produced through the reassembly of extant haemoglobin subunits. The final hypothesis is that changes in isomorph abundance occur through the production of new erythrocytes with red blood cells ‘pre-programmed’ to produce a particular set of haemoglobins. Changes originating from production of new erythrocytes would require longer periods of time before being detectable; weeks to months depending on the temperature regime. To test this, paired groups of rainbow trout were subjected to either 10ºC or 20ºC for 5, 7, 14, 21 and 28 days. A total of 14 isomorphs were observed after the haemolysate was separated using cellulose acetate electrophoresis. However, no detectable differences in isomorph abundance were found between treatment groups. In a follow-up experiment, anaemia was induced in rainbow trout to stimulate the production of new erythrocytes. The trout were then held at either 10ºC or 20ºC for 21 days. This resulted in relative increases in the abundance of anodal haemoglobin isomorphs in the 20ºC acclimated group and a corresponding decrease in cathodal haemoglobin isomorphs. To further confirm that changes in abundance were occurring through the production of new erythrocytes, separation of erythrocytes into age classes was undertaken to compare the isomorphs present in mature erythrocytes with those from erythrocytes produced under amended temperature regimes. Using Percoll density gradients, red blood cells from anaemia-induced trout acclimated to either 10ºC or 20ºC were enriched into mature and young erythrocyte fractions. Further significant differences in abundance were found between both anodal and cathodal isomorphs when compared between treatment groups. From these results it was concluded that changes in haemoglobin isomorph abundance originated from the production of new erythrocytes. Cellulose acetate gel electrophoresis was carried out on seven haemoglobin fractions that had undergone prior separation from whole haemolysate by Fast Protein Liquid Chromatography. Each haemoglobin fraction was found to be composed of two isomorphs for a total of 14 haemoglobin isomorphs. The oxygen binding properties of each fraction was examined under varying conditions of temperature, pH, ATP and chloride concentrations. Cathodal functional groups HbI to HbIII were found to be insensitive to temperature, pH, chloride and the organic phosphate ATP. In contrast, the anodal fractions (HbIV to HbVII) all responded to pH and temperature changes, while HbVI and HbVII responded to ATP. However, no fraction responded to increased chloride concentrations. These results suggest that different varieties of rainbow trout may produce different forms of haemoglobin as part of an adaptive response to local environmental conditions, leading to variation in the functional properties of some of the less abundant functional groups such as HbIII. Despite the theory that cathodal haemoglobins function as emergency back-up supplies of oxygen being proposed more than thirty years ago, no published information can be found for it being tested in the laboratory. Two groups of anaemia-induced rainbow trout were placed in a divided annular flume for 24 days. The high activity group was subjected to a forced swimming speed of 2.5 body lengths (B.L.) s-1 for 6 h d-1. When not undergoing forced exercise the treatment group were maintained at the same speed as the low activity group of 0.5 B.L. s-1. Significant differences in haemoglobin isomorph abundance were present between the initial samples taken at the time of anaemia induction and high and low activity groups. However, only the C4 isomorph demonstrated a significant difference between high and low activity groups. When total anodal and cathodal isomorphs were compared between initial state, high activity and low activity groups, no differences were present. These data suggest that the induction of anaemia had an effect on the composition of the isomorphs but no physiological effect on oxygen delivery. In addition, the swimming velocity of 2.5 B.L. s-1 employed for the high activity group may have been an insufficient stimulus to induce changes in isomorph abundance. It is concluded that changes in haemoglobin isomorph abundance occur in response to chronic changes in the environment. Increases in the abundance of anodal isoforms in response to increasing temperature allows for increased delivery of oxygen to tissues undergoing increases in metabolic activity associated with higher temperatures. The multiple haemoglobin isomorphs of rainbow trout provide an increased efficiency in delivery of oxygen to tissues under varying metabolic conditions of pH, temperature and oxygen saturation. The cathodal and anodal haemoglobin functional groups of rainbow trout exhibit different oxygen affinities in response to temperature, pH and ATP concentration but not to physiologically realistic chloride concentrations. The oxygen binding properties of the isomorphs within the cathodal and anodal functional groups are broadly similar. However, differences in responses by the anodal functional groups to NTPs may exist. An examination of the hypothesis that cathodal haemoglobins act as reserve oxygen delivery sources under prolonged activity produced no significant results. However, this hypothesis still remains viable and needs to be tested under different experimental conditions. This work provides a basis for further research into the adaptive abilities of rainbow trout. The selection of rainbow trout which better adapt to wide ranges of environmental conditions would allow for targeted introduction by fisheries managers to aquatic systems previously not considered optimal for trout growth thereby expanding the fishery.

year: 2011

title: Characterizing heart rate differences across rugby union competition levels

authors: Koumandarakis, Nikolas

subjects: Internal load

abstract: Heart rate (HR) monitoring provides insight into the demands of rugby union and may be able to help discriminate between different levels of competition. There is limited data examining the differences in physiological responses among different levels of rugby union. Rugby union athletes from different levels of competition (n=15 School, n=15 Club, n=15 Professional, and n=15 International) were included in the study. HR was measured via chest straps worn during the game with specific variables compared between levels of competition (e.g. Average (Avg) HR (bpm), and HR during worst-case scenario (WCS) periods of play (1, 2, 3, 4 and 5 minutes). Data was collected from eight matches for International, six matches for Professional and Club, and with School only able to play four due to season constraints. A one-way ANOVA revealed statistically significant differences in Avg HR across the four competition levels (p < 0.05). School players recorded the highest Avg HR (175 ± 10 bpm), while International players had the lowest (159 ± 9 bpm). Club and Professional teams had similar values, with no significant difference between them (p = 0.72). This trend was consistent across both forwards and backs. WCS HRs over rolling 1–5-minute intervals followed the same pattern, with School players consistently recording the highest values and International players the lowest. The largest WCS difference was observed at the 2-minute interval between School (191 ± 9 bpm) and International (179 ± 6 bpm) teams. Tukey post-hoc tests confirmed that School and International were significantly different from all other groups, while Club and Professional teams did not differ significantly. To the authors knowledge, this study is the first to compare heart rate metrics through different levels of competition in rugby union and is timely as the age of professional players is getting lower. Coaches should consider accurately tailor training to prepare athletes for optimal performance across different levels of competition as HR provides an accurate measure of internal load and could be more effective than the commonly used measures of external load e.g. GPS.

text: Characterizing heart rate differences across rugby union competition levels Heart rate (HR) monitoring provides insight into the demands of rugby union and may be able to help discriminate between different levels of competition. There is limited data examining the differences in physiological responses among different levels of rugby union. Rugby union athletes from different levels of competition (n=15 School, n=15 Club, n=15 Professional, and n=15 International) were included in the study. HR was measured via chest straps worn during the game with specific variables compared between levels of competition (e.g. Average (Avg) HR (bpm), and HR during worst-case scenario (WCS) periods of play (1, 2, 3, 4 and 5 minutes). Data was collected from eight matches for International, six matches for Professional and Club, and with School only able to play four due to season constraints. A one-way ANOVA revealed statistically significant differences in Avg HR across the four competition levels (p < 0.05). School players recorded the highest Avg HR (175 ± 10 bpm), while International players had the lowest (159 ± 9 bpm). Club and Professional teams had similar values, with no significant difference between them (p = 0.72). This trend was consistent across both forwards and backs. WCS HRs over rolling 1–5-minute intervals followed the same pattern, with School players consistently recording the highest values and International players the lowest. The largest WCS difference was observed at the 2-minute interval between School (191 ± 9 bpm) and International (179 ± 6 bpm) teams. Tukey post-hoc tests confirmed that School and International were significantly different from all other groups, while Club and Professional teams did not differ significantly. To the authors knowledge, this study is the first to compare heart rate metrics through different levels of competition in rugby union and is timely as the age of professional players is getting lower. Coaches should consider accurately tailor training to prepare athletes for optimal performance across different levels of competition as HR provides an accurate measure of internal load and could be more effective than the commonly used measures of external load e.g. GPS.

year: 2025

title: Data and model bias in artificial intelligence for healthcare applications in New Zealand

authors: Yogarajan, Vithya

abstract: Introduction: Developments in Artificial Intelligence (AI) are adopted widely in healthcare. However, the introduction and use of AI may come with biases and disparities, resulting in concerns about healthcare access and outcomes for underrepresented indigenous populations. In New Zealand, Māori experience significant inequities in health compared to the non-Indigenous population. This research explores equity concepts and fairness measures concerning AI for healthcare in New Zealand. Methods: This research considers data and model bias in NZ-based electronic health records (EHRs). Two very distinct NZ datasets are used in this research, one obtained from one hospital and another from multiple GP practices, where clinicians obtain both datasets. To ensure research equality and fair inclusion of Māori, we combine expertise in Artificial Intelligence (AI), New Zealand clinical context, and te ao Māori. The mitigation of inequity needs to be addressed in data collection, model development, and model deployment. In this paper, we analyze data and algorithmic bias concerning data collection and model development, training and testing using health data collected by experts. We use fairness measures such as disparate impact scores, equal opportunities and equalized odds to analyze tabular data. Furthermore, token frequencies, statistical significance testing and fairness measures for word embeddings, such as WEAT and WEFE frameworks, are used to analyze bias in free-form medical text. The AI model predictions are also explained using SHAP and LIME. Results: This research analyzed fairness metrics for NZ EHRs while considering data and algorithmic bias. We show evidence of bias due to the changes made in algorithmic design. Furthermore, we observe unintentional bias due to the underlying pre-trained models used to represent text data. This research addresses some vital issues while opening up the need and opportunity for future research. Discussions: This research takes early steps toward developing a model of socially responsible and fair AI for New Zealand's population. We provided an overview of reproducible concepts that can be adopted toward any NZ population data. Furthermore, we discuss the gaps and future research avenues that will enable more focused development of fairness measures suitable for the New Zealand population's needs and social structure. One of the primary focuses of this research was ensuring fair inclusions. As such, we combine expertise in AI, clinical knowledge, and the representation of indigenous populations. This inclusion of experts will be vital moving forward, proving a stepping stone toward the integration of AI for better outcomes in healthcare.

text: Data and model bias in artificial intelligence for healthcare applications in New Zealand Introduction: Developments in Artificial Intelligence (AI) are adopted widely in healthcare. However, the introduction and use of AI may come with biases and disparities, resulting in concerns about healthcare access and outcomes for underrepresented indigenous populations. In New Zealand, Māori experience significant inequities in health compared to the non-Indigenous population. This research explores equity concepts and fairness measures concerning AI for healthcare in New Zealand. Methods: This research considers data and model bias in NZ-based electronic health records (EHRs). Two very distinct NZ datasets are used in this research, one obtained from one hospital and another from multiple GP practices, where clinicians obtain both datasets. To ensure research equality and fair inclusion of Māori, we combine expertise in Artificial Intelligence (AI), New Zealand clinical context, and te ao Māori. The mitigation of inequity needs to be addressed in data collection, model development, and model deployment. In this paper, we analyze data and algorithmic bias concerning data collection and model development, training and testing using health data collected by experts. We use fairness measures such as disparate impact scores, equal opportunities and equalized odds to analyze tabular data. Furthermore, token frequencies, statistical significance testing and fairness measures for word embeddings, such as WEAT and WEFE frameworks, are used to analyze bias in free-form medical text. The AI model predictions are also explained using SHAP and LIME. Results: This research analyzed fairness metrics for NZ EHRs while considering data and algorithmic bias. We show evidence of bias due to the changes made in algorithmic design. Furthermore, we observe unintentional bias due to the underlying pre-trained models used to represent text data. This research addresses some vital issues while opening up the need and opportunity for future research. Discussions: This research takes early steps toward developing a model of socially responsible and fair AI for New Zealand's population. We provided an overview of reproducible concepts that can be adopted toward any NZ population data. Furthermore, we discuss the gaps and future research avenues that will enable more focused development of fairness measures suitable for the New Zealand population's needs and social structure. One of the primary focuses of this research was ensuring fair inclusions. As such, we combine expertise in AI, clinical knowledge, and the representation of indigenous populations. This inclusion of experts will be vital moving forward, proving a stepping stone toward the integration of AI for better outcomes in healthcare.

year: 2022-12-22