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    Perioperative fluid administration to optimise haemodynamics without fluid overload in anaesthetised dogs : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatu, New Zealand
    (Massey University, 2021) Sano, Hiroki
    Perioperative fluid therapy is the mainstay of anaesthetic management. Fluid administration improves haemodynamics during anaesthesia as it increases preload and thus cardiac output and blood pressure. However, excessive fluid administration can cause detrimental adverse effects, such as haemodulution and oedema, resulting in prolonged hospital stay and increased morbidity and mortality in people. Therefore, fluid administration should be restricted to those who are able to increase stroke volume or cardiac output in response to the fluid administration (responders) and should not be given to those who are unable to do so (non-responders) based on the famous “Frank–Starling law of the heart” Previously static parameters such as central venous pressure were believed to be a clinical gold standard to estimate preload and fluid responsiveness. Over the last decade, dynamic parameters such as pulse pressure variation and pleth variability index have been shown to be reliable predictors for fluid responsiveness in people. This study found that pulse pressure variation and pleth variability index were more accurate than central venous pressure for predicting fluid responsiveness in dogs. Mini-fluid challenge is another technique that is currently available and can be reliably used to determine fluid responsiveness in human medicine. Mini-fluid challenge is an administration of a small amount of fluid to increase preload. Thus, fluid responsiveness can be assessed based on whether stroke volume increases following mini-fluid challenge according to the Frank-Starling curve. The change in stroke volume of a heart at the steep portion of the Frank-Starling curve will be greater than at the plateau portion after mini-fluid challenge. The studies revealed a percentage change in pulse wave transit time (a surrogate parameter of stroke volume, which was also one of results in this thesis) following mini-fluid challenge could predict fluid responsiveness in mechanically ventilated anaesthetised dogs under an experimental condition, and spontaneously breathing anaesthetised dogs undergoing stifle surgery in clinical setting. Lastly, these methods are still of limited use in veterinary clinical practice because of availability of equipment, difficulty of their interpretation and a cumbersome process. The main purpose of this thesis was to obtain evidence on how to optimise haemodynamics in anaesthetised dogs and prevent excessive fluid administration. The time when most practitioners administer a bolus of fluid during anaesthesia is when hypotension is encountered because of anaesthesia. Thus, prevention of hypotension could avoid excessive fluid administration. Therefore, the study found that prophylactic noradrenaline administration, which counteracts some of the cardiovascular adverse effects of anaesthesia, was able to prevent hypotension, and thus minimise fluid administration in anaesthetised dogs. Although all of these methods tested in this thesis have pros and cons in clinical veterinary practice, they were shown to be able to optimise haemodynamics without fluid overload in anaesthetised dogs.
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    Cryopreservation and genetic damage : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Genetics at Massey University
    (Massey University, 2005) Major, Ruth Esther
    Blood analysis is time consuming and laboratories may require methods of storing samples until time permits analysis. The effects of storage on the sample are mostly unknown, yet some laboratories commonly store blood samples to allow processing of samples in batches. Cryopreservation is proposed as a convenient means of preserving blood samples, as the associated cold temperatures render cryopreservation an ideal storage method for tests requiring viable cells. In the literature, few studies have explored whether cryopreserved whole blood samples can be utilised effectively for cytogenetic testing. This study extended the work on cryopreservation of blood to observe the cytogenetic effects of storing whole blood samples for an extended period. In this study three cytogenetic tests: Sister Chromatid Exchange (SCE), Micronucleus Assay (MN) and Fluorescence in situ Hybridisation (FISH) were conducted on whole blood samples from ten participants to observe whether the results from the cytogenetic tests are statistically consistent over a prolonged period of cryopreservation (fresh, one month, three months and six months). These tests were conducted on a single blood sample cryopreserved from each participant. The results indicated that cryopreservation of whole blood is not a reliable method for storing blood samples prior to cytomolecular tests. The culturing of lymphocytes from cryopreserved blood was found to be inconsistent and the lymphocyte viability after cryopreservation reduced. When lymphocytes were successfully cultured, SCE and MN demonstrated increased genetic damage after a period of cryopreservation (P= <0.050 and P= 0.016 respectively) but FISH was not successfully performed on cryopreserved blood samples. It is unclear from the results obtained whether cryopreservation actually induces genetic damage or if the observed damage was the result of the specific storage technique.
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    Some physiological changes in female athletes during and after exercise : investigating the use of a new, low-invasive sampling method (electrosonophoresis) : a thesis in partial fulfilment of the requirements for the degree of Master of Science in Exercise Physiology at Massey University, Palmerston North, New Zealand
    (Massey University. Institute of Food, Nutrition and Human Health, 2003) Purnell, Heather Margaret
    The purpose of this study was to monitor cardiovascular and endocrine changes in sedentary and training females during a six week period, and to assess the accuracy of a new, low-invasive sampling methodology (electrosonophoresis). Changes in fitness were measured using oxygen consumption (VO2). The impact on VO2 of sleep quality, sleep duration and alcohol consumption (recorded in sleep logs) was assessed. Cortisol, testosterone and growth hormone levels in plasma were monitored for acute changes following fitness tests, and chronic changes related to training, oral contraceptive use or alcohol consumption. Hormone concentrations in blood and saliva samples were compared to those in interstitial fluid (obtained using electrosonophoresis) to investigate the accuracy of electrosonophoresis. Mean VO2 increased by 3.3 ± 1.3mL/kg/min between Week 1 and Week 5 and the changes detected in heart rate (HR) during the fitness tests suggest that aerobic fitness of the training participants increased across the study. No significant associations between sleep quality, sleep duration or alcohol consumption and VO2 were detected. No acute changes in plasma hormone concentrations following fitness tests were detected. No chronic changes in plasma cortisol or testosterone concentrations were detected, although a non-significant trend towards increased plasma GH levels in training participants was detected. Resting plasma cortisol levels were significantly lower in oral contraceptive users compared with non-users. Plasma testosterone and growth hormone levels were unaffected by oral contraceptive use. Alcohol consumption had no acute detectable effects on plasma concentrations of the three hormones. Plasma testosterone levels were higher in participants who abstained from alcohol, and higher plasma growth hormone levels were detected in heavy drinkers. These results contrast with published reports. Concentrations of the three hormones in interstitial fluid and plasma exhibited highly significant positive correlations (r2 > 0.98) with an interstitial fluid:plasma concentration ratio of about 1:10 in each case. Equations to predict plasma concentrations of cortisol, testosterone and growth hormone from interstitial fluid concentrations have been derived. The electrosonophoretic method apparently provides an accurate, painless, low-invasive method for prediction of the plasma levels of these three hormones. This technology has far-reaching implications for research in human, animal and biomedical fields.