Simultaneous maternal indirect blood pressure measurements, electronic fetal heart rate monitoring, and ultrasonographic biophysical profile testing were used to assess maternal-fetal homeostasis in gravid ewes during gestational days 127 to 134 (term 146), during a 72-hour fast, and during treatment with thromboxane synthetase inhibitors CGS13080 and CGS12970. Seventy-five percent of the ewes (12 of 16) developed clinical signs of ovine pregnancy-induced hypertension, including maternal hypertension and fetal depression. In three untreated hypertensive ewes, pregnancy was terminated by spontaneous premature delivery, and one maternal death occurred after an eclamptic seizure. All nine ewes treated with one of the two thromboxane synthetase inhibitors responded to therapy with decreases in blood pressure and resolution of fetal depression. These nine ewes completed gestation, and were delivered at term. These data indicate that therapy with thromboxane synthetase inhibitors in this animal model of preeclampsia results in profoundly beneficial effects and suggest that further studies of thromboxane synthetase inhibitors are warranted in preeclampsia.

No description available.

A dissertation submitted in fulfilment of the requirements for the degree Master of Science in Engineering, in the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg. January 2017 Johannesburg / It is well known that emotional stress has a negative impact on people’s health and physical, emotional and mental performance. Previous research has investigated the effects of stress on various aspects of physiology such as respiration, heart rate, heart rate variability (HRV), skin conductance, skin temperature and electrical activity in the brain. Essentially, HRV, Electroencephalography (EEG), skin conductance and skin temperature appear to reflect a stress response or state of arousal. Whilst the relationship between respiration rate, respiration rhythm and HRV is well documented, less is known about the relationship between respiration rate, EEG, skin conductance and skin temperature, whilst HRV is maximum (when there is resonance between HRV and respiration i.e. in phase with one another). This research project aims to investigate the impact that one session of slow paced breathing has on EEG, heart rate variability (HRV), skin conductance and skin temperature. Twenty male participants were randomly assigned to either a control or intervention group. Physiological data were recorded for the intervention and control group during one breathing session, over a short initial baseline (B1), a main session of 12 minutes, and a final baseline (B2). The only difference between the control and intervention groups was that during the main session, the intervention group practiced slow paced breathing (at 6 breaths per minute), while the control group breathed spontaneously. Wavelet transformation was used to analyse EEG data while Fourier transformation was used to analyse HRV. The study shows that slow-paced breathing significantly increases the low frequency and total power of the HRV but does not change the high frequency power of HRV. Furthermore, skin temperature significantly increased for the control group from B1 to Main, and was significantly higher for the control group when compared to the intervention group during the main session. There were no significant skin temperature changes between sessions for the intervention group. Skin conductance increased significantly from Main to B2 for the control group. No significant changes were found between sessions for the intervention group and between groups. EEG theta power at Cz decreased significantly from Main to B2 for the control group only, while theta power decreased at F4 from Main to B2 for both groups. Lastly, beta power at Cz decreased from B1 to B2 for the control group only. This significant effect that slow-paced breathing has on HRV suggests the hypothesis that with frequent practice, basal HRV would increase, and with it, potential benefits such as a reduction in anxiety and improved performance in specific tasks. Slow-paced breathing biofeedback thus shows promise as a simple, cheap, measurable and effective method to reduce the impact of stress on some physiological signals, suggesting a direction for future research. / MT2017

Wu, Kin Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 88-91). / Abstracts in English and Chinese. / Abstract --- p.i / 槪要 --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.x / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Outline of the Proposed Design --- p.2 / Chapter 1.3 --- Purposes of the Present Study --- p.2 / Chapter Chapter 2 --- Background and Literature Review --- p.4 / Chapter 2.1 --- Electrocardiogram --- p.4 / Chapter 2.2 --- Conventional ECG Measurement --- p.7 / Chapter 2.3 --- Heart Rate --- p.8 / Chapter 2.4 --- Heart Rate Variability --- p.9 / Chapter 2.5 --- Capacitive Sensing --- p.11 / Chapter 2.6 --- Review of ECG Monitoring System by Capacitive Sensing On a Sleeping Bed --- p.14 / Chapter Chapter 3 --- System Design and Implementation --- p.17 / Chapter 3.1 --- Hardware --- p.17 / Chapter 3.1.1 --- Bedsheet Sensor --- p.17 / Chapter 3.1.2 --- Pre-amplifier --- p.21 / Chapter 3.1.3 --- Measuring Device --- p.30 / Chapter 3.1.4 --- Power Supply & PCB Layout --- p.49 / Chapter 3.2 --- Software --- p.52 / Chapter 3.2.1 --- Detection of R Waves --- p.52 / Chapter 3.2.2 --- Tracking of HR & Mean RR Intervals --- p.55 / Chapter 3.2.3 --- Estimation of Signal-to-Noise Ratios --- p.56 / Chapter Chapter 4 --- Preliminary Tests on the Functionality of the Proposed System --- p.57 / Chapter 4.1 --- Test I - Test on the Arrangement of Electrodes --- p.57 / Chapter 4.1.1 --- Methods --- p.57 / Chapter 4.1.2 --- Results --- p.60 / Chapter 4.2 --- Test II - Test on the ECG Measurement of Subjects in Different Sleeping Postures --- p.64 / Chapter 4.2.1 --- Methods --- p.64 / Chapter 4.2.2 --- Results --- p.65 / Chapter Chapter 5 --- Experiments on the Performance of Continuous Monitoring of ECG and HR --- p.69 / Chapter 5.1 --- Experiment I - Experiment on the Reliability of the Proposed System for Continuous Monitoring of ECG and HR on Thirty Subjects --- p.69 / Chapter 5.1.1 --- Methods --- p.70 / Chapter 5.1.2 --- Results --- p.70 / Chapter 5.2 --- Experiment II - Experiment on the Feasibility of the Proposed System for Continuous Monitoring of ECG and HR on a Subject During an Eight-hour Sleep --- p.75 / Chapter 5.2.1 --- Materials --- p.76 / Chapter 5.2.2 --- Methods --- p.76 / Chapter 5.2.3 --- Results --- p.77 / Chapter Chapter 6 --- Discussions --- p.81 / Chapter 6.1 --- Selection of the Passband of the Proposed Circuit --- p.81 / Chapter 6.2 --- Arrangement of Electrodes on the Bedsheet --- p.82 / Chapter 6.3 --- Practical Design of Electrodes --- p.83 / Chapter 6.4 --- Performance of Continuous Monitoring of HR by Using the Proposed System --- p.84 / Chapter Chapter 7 --- Conclusion --- p.86 / References --- p.88

No description available.

In this thesis, I examine the use of medical technology as the product of, among other things, value systems and individual and collective needs; technological use therefore is shown to be culturally influenced and subject to change according to historical and social context. / I describe and discuss the use of the Electronic Fetal Heart Rate Monitor (EFM)--a state of the art form of electronic information technology--in obstetrical care in a rural Canadian hospital and community. The central issue I examine is why this technology was obtained and repeatedly used despite local medical opinion and scientific evidence that it was ineffective as a tool to improve obstetrical outcome, and also had been shown to put pregnant women at considerable risk of unnecessary and potentially harmful interventions during birth. / I describe how EFM use appeared contradictory because medical understanding of EFM use was limited to what I define as "case centered" research; research limited to measuring the impact of the EFM on individual patient outcome. Case centered studies were not examinations either of the EFM itself, or of its associated technical regimens. Moreover, case centered studies were not used to relate the EFM to women's experiences during birth, hospital traditions, or community expectations. These latter relationships, which are ignored in case studies, form the focus of this research and explain why an EFM was used in this community.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 80-94). / Microfiche. / vii, 94 leaves, bound 29 cm

The primary purpose of CTG is to detect early signs of intrapartum hypoxia and improve foetal outcomes. Intrapartum hypoxia remains the major cause of perinatal deaths mainly in monitored labours. This is attributed to the midwives’ lack of skills in the foetal implementation and interpretation of CTG. Midwives interpret foetal heart rate patterns erroneously hence they fail to detect early signs of severe foetal compromise. Accurate interpretation of CTG is the cornerstone for clinical decision during intra-partum foetal surveillance. Therefore, it is mandatory that midwives are competent in CTG. The purpose of the study was to explore and describe the perceptions of midwives in KwaZulu-Natal public hospitals regarding their level of competence related to the CTG. The purpose of the study was to explore and describe the perceptions of midwives in KwaZulu-Natal public hospitals regarding their level of competence related to the CTG. The objectives of this study were: -to explore and describe the perceptions of the midwives regarding their level of competence relating to cardiotocography. -to establish the levels of competence of midwives in relation to CTG. -to develop clinical guidelines that could be utilised by midwives in the implementation and interpretation of the cardiotocograph. The study utilised a quantitative non-experimental comparative descriptive research design. A self-developed and self-administered questionnaire was developed under the supervision of a statistician and was to collect data from a purposively selected sample of midwives who work in labour wards in Kwa-Zulu Natal public hospitals. A sample of 226 practicing midwives working in labour wards of the nine KZN public hospitals was selected using a non-probability convenience sampling method; only 125 responded. Data were collected on an excel spread sheet and analysed under the supervision of the statistician and research supervisor. The researcher assured of validity and reliability of the data collection method and data as well as of the data collection instrument. The findings revealed that the midwives in KZN public hospitals perceived themselves as being competent regarding CTG tasks; however they lack knowledge and skills in the implementation and interpretation of CTG. It was also evident that the midwives’ years of midwifery clinical experience, labour ward experience, possession of additional post basic midwifery qualification and the perceived level of competence related to CTG tasks number of years of the midwives did not influence their level of competence in the implementation and interpretation of CTG. Literature control supported these findings and there was consistency with that literature. Recommendations were made and clinical guidelines were developed to assist midwives with the assessment of foetal heart rate and the interpretation of the cardiotocograph results.

This study examined effectiveness of heart rate variability (HRV) biofeedback-assisted stress management training in reducing anxiety and stress in pregnant women and the effect of maternal stress management skills practice on fetal heart rate measures in real time. Participants were seven working pregnant women who volunteered in response to recruitment announcements and invitations from cooperating midwives. Reported state and trait anxiety and pregnancy specific stress were measured during five 45- to 50-minute training sessions. Training included bibliotherapy, instruction in the use of emotion-focused stress management techniques, and HRV biofeedback. Subjects used portable biofeedback units for home practice and were encouraged to practice the skills for 20 minutes a day and for short periods of time during stressful life events. At the end of training, fetal heart rate was monitored and concurrent maternal HRV measures were recorded. Repeated measures ANOVA and paired samples t-test analysis of study data revealed no statistically significant reductions in state or trait anxiety measures or in pregnancy specific stress measures. Partial eta squared (n²) and Cohen's d calculations found small to medium effect sizes on the various test scales. Friedman's analysis of variance of biofeedback measures showed a statistically significant decrease in low HRV coherence scores (X2 = 10.53, p = .03) and medium HRV coherence scores (X2 = 11.58, p = .02) and a statistically significant increase in high HRV coherence scores (X2 = 18.16, p = .001). This change is an indication of improved autonomic function. Results of concurrent maternal and fetal HRV recordings were generally inconclusive. A qualitative discussion of individual subject results is included. During follow-up interviews five subjects reported that they felt they were better able to cope with stress at the end of the study than at the beginning, that they used the stress management skills during labor, and that they continue to practice the skills in their daily lives.

The prevalence of obesity continues to increase despite considerable research and innovation regarding treatment and management strategies. When completed as prescribed, exercise training is associated with numerous health benefits and predictable levels of weight loss. However, under free-living conditions the benefits of exercise are less consistent, suggesting that non-adherence and/or a compensatory response in non-exercise activity thermogenesis (NEAT) may be occurring. The accurate quantification of all components of total energy expenditure (TEE), including TEE itself, was imperative to elucidate the primary research question relating to the impact of exercise on TEE. In addition, the measurement of changes in body composition and the response to prescribed exercise were assessed in methodological and pilot investigations. Following this extensive background, the primary research question relating to the effect of exercise on levels of TEE and the associated implications of such a compensatory response could be more rigorously investigated. The first study investigated the variability in isotopic equilibrium time under field conditions, and the impact of this variability on estimates of total body water (TBW) and body composition when using the deuterium dilution technique. Following the collection of a fasting baseline urine sample, 10 women and 10 men were dosed with deuterium oxide (0.05g/kg body weight). Urine samples were collected every hour for 8 hours. The samples were analysed using isotope ratio mass spectrometry and time to equilibration was determined using three commonly employed data analysis approaches. Isotopic equilibrium was reached by 50, 80 and 100% of participants at 4, 6 and 8 h, respectively. The mean group equilibration times determined using the three different plateau determination methods were 4.8 ± 1.5, 3.8 ± 0.8, and 4.9 ±1.4 h, respectively. Isotopic enrichment, TBW, and percent body fat estimates differed between early sampling times (3-5 h), but not later sampling times (5-8 h). Therefore, sampling < 6 hours post dose compared to sampling ≥ 6 hours resulted in greater relative measurement error in TBW and body composition estimates. Although differences in equilibration time were apparent between the three plateau determination approaches, sampling at 6 hours or later may decrease the likelihood of error in body composition estimates resultant from incomplete isotopic equilibration in a small proportion of individuals. In the second study, the aim was to measure the self-paced walking (SPW) speed of adults ranging in body size from normal to obese. The utility of heart rate monitors to estimate the energy cost of walking was also investigated. Twenty-nine participants (12 normal-weight, 17 overweight or obese) completed two outdoor walking tests to determine their SPW speed. A walking treadmill test with stages below, at, and above the SPW speed was completed to compare the energy expenditure estimates of the Polar S610 and WM42 heart rate monitors with that from indirect calorimetry. The average SPW speed was 1.7 ± 0.1 m*sec-1, which was equivalent to an exercise intensity of 48.6 ± 9.4 %VO2max (61.0 ± 7.1 %HRmax). There was no difference in the energy expenditure estimation between indirect calorimetry (4.7 ± 0.7 kcal*kg*-1*h-1), the S610 (4.8 ± 1.3 kcal*kg*-1*h-1) and the WM42 (4.8 ± 1.6 kcal*kg*-1*h-1). It was concluded that the heart rate monitors provided reasonable energy expenditure estimates at the group level. However considerable error was evident at the individual level, explained in part by exercise heart rate and fitness level, suggesting that an individualised calibration should be performed where possible. An additional finding from this study was that 145 to 215 minutes of SPW per week, dependent upon the level of adiposity, is required to meet the current American College of Sports Medicine (ACSM) guidelines for health of 1000 kcal*wk-1. The purpose of the third study was to establish the level of adherence to a specific exercise prescription (1500 kcal*wk-1) by objectively quantifying unsupervised exercise energy expenditure (ExEE) in a group of obese women. The 16-wk lifestyle intervention consisted of weekly meetings with research staff, combined with promotion of increased ExEE (1500 kcal*wk-1) and a decreased dietary intake (-500 kcal*d-1). Twenty-nine obese females (Body Mass Index = 36.8 ± 5.0 kg*m2, Body Fat = 49.6 ± 3.7 %) from a hospital-based lifestyle intervention were included in the analysis. ExEE was estimated and monitored weekly using heart rate monitoring. Body composition was measured before and after the intervention by dual-energy x-ray absorptiometry (DXA). Results indicated free-living adherence to the exercise prescription was modest and variable, with 14% of participants achieving the 1500 kcal*wk-1. The average weekly ExEE (768 kcal*wk-1) represented 51.2% of the total amount prescribed. ExEE was correlated with changes in body weight (r = 0.65, p < 0.001) and fat mass (r = 0.65, p = 0.0002). Achievement of a 5% weight loss target was dependent on an ExEE level of 1000 kcal*wk-1 (p &lt0.001). Exercise 'adherers' (> 000 kcal*wk-1) lost more weight (-9.9 vs. -4.1 kg), more fat mass (-6.8 vs. -3.0 kg), and more waist circumference (-9.8 vs. -5.6 cm) when compared to 'non-adherers' (< 1000 kcal*wk-1). The results suggest that the extent of supervision and monitoring influenced exercise adherence rates. The variability in adherence highlights the importance of objective monitoring of ExEE. Identification of individuals not complying with program targets may enable intervention staff to provide additional support or make individualised adjustments to the exercise prescription. The fourth study investigated issues relating to the management and interpretation of accelerometry data when the device is to be used to monitor levels of daily physical activity. Given the high between-individual variability in accelerometry output for a given walking speed, the use of a more individualised approach to the data management has been suggested. In addition, accelerometry was used to compare daily physical activity patterns between a supervised and unsupervised exercise prescription of the same dose (1500 kcal*wk-1) in overweight and obese women. Total energy expenditure, activity energy expenditure, and vector magnitude increased significantly during the intervention. Time spent in very low intensity movement decreased from baseline to the intervention (p < 0.01) in both the supervised (-18.6 min*d-1) and unsupervised (-68.5 min*d-1) group, whereas time spent in high and vigorous intensity movement increased significantly from baseline to the intervention (p < 0.05 and p < 0.0001, respectively). The increase in vigorous movement was significantly greater in the supervised group when compared to the unsupervised group (+11.5 vs. +5.4 min*d-1, p < 0.05). Time spent above three different moderate-intensity walking thresholds increased from baseline to the intervention (p < 0.0001). The threshold determination approach significantly affected the resultant outcomes (p < 0.0001) such that the standard threshold was significantly different to both group-specific and individualised approaches. Significant differences were also noted in accelerometer output between treadmill and overground walking (p < 0.0001). A positive finding of this study was that two different interventions aimed at increasing physical activity levels in a group of sedentary and obese women were successful in gaining modest increases in overall daily movement. The change observed appears to be a replacement of sedentary movement with more vigorous physical activity. Collectively, the differences observed between threshold determination approaches, as well as between treadmill and overground walking, highlight the need for standardised approaches to accelerometry data management and analysis. In addition, the findings suggest that obese women may benefit from a certain degree of exercise supervision to ensure compliance, however, strategies to encourage these women to continue with the exercise on their own without supervision are essential to making a sustainable long-term change to their lifestyles. The final study aimed to assess whether obese women compensate for structured exercise by decreasing their NEAT and thereby impeding weight loss. Thirteen participants were prescribed 1500 kcal*wk-1 of exercise through a structured walking program (4 week supervised followed by 4 weeks unsupervised). The energy expenditure of the walks was quantified using individually-calibrated Polar F4 heart rate monitors. The DLW technique was used to measure TEE. Accelerometry measures were also collected throughout and represented an alternative method of quantifying changes in total daily movement patterns resultant from an increase in energy expenditure through exercise. Compliance with the exercise program was excellent, with the average compliance being 94% over the 8-week intervention. The adoption of moderate-intensity exercise in this group of obese women resulted in a 12% decrease in TEE (p = 0.01) and a 67% decrease in NEAT (p < 0.05). No significant change was observed in resting metabolic rate from baseline to the postintervention time-point. Compensation was significantly correlated with dietary report bias (r= -0.84, p = 0.001), body image (r = 0.75, p < 0.01), and bodily pain (r = -0.65, p < 0.05). A linear regression model including dietary reporting bias and the pain score explained 78% of the variation in ΔTEE. Compensators were therefore less likely to underreport their dietary intake, less likely to be self-aware of their obese state, and more likely to be experiencing pain in their daily life. Self-reported dietary intake decreased significantly during the intervention (p = 0.01) with specific decreases noted in fat and carbohydrate intake. The consequence of compensation was evidenced by a lack of significant change in body weight, body composition, or blood lipids (p > 0.05). However, positive outcomes of the study included improvement in the SF-36 scores of general health (p < 0.05) and maintenance of exercise program adherence into the unsupervised phase of the intervention. Qualitative data collected via interview indicated that 85% of participants experienced increased energy and positive feedback from peers during the intervention. This study confirms that exercise prescription needs to be prescribed with an individualised approach that takes into account level of adiposity. The goal of exercise prescription for the obese should therefore be to determine the intensity and modality of exercise that does not activate compensatory behaviours, as this may in turn negate the beneficial effects of the additional energy expenditure of exercise. This study confirms that during the initial phase of an exercise-based weight loss intervention, the majority of obese women compensated for some, if not all, the energy cost of the exercise sessions by reducing NEAT. Whether this compensatory behaviour continues beyond the first month of an exercise program, particularly after training adaptations in cardiorespiratory fitness are realised, cannot be discerned from the current study. However these results do provide a rationale for why the magnitude of weight loss achieved is often less than predicted during exercise interventions. Further research is required to examine the temporal pattern of compensation in NEAT, and the relationship between the time courses of NEAT compensation relative to physical fitness improvements. The results from this thesis support the use of activity monitors such as accelerometers during weight loss interventions to track NEAT and provide objective feedback regarding compensatory behaviours to clinicians and the obese individuals.