The intention of the study is to evaluate the risk of artemisinin in early pregnancy through the use of a qualitative research approach, with a focus on rural women in Babati District, Manyara Region, Tanzania. Artemisinin-Based Combination Therapy (ACT) is the most effective and recommended antimalarial treatment at the present. Artemisinin compounds are extracted from Artemisia annua, a plant which has been used as an herbal medical treatment in China for 2000 years. Except few side-effects, there have not been any reports on medical problems due to artemisinin intake during pregnancy. On the other hand, artemisinin tested on animals have revealed that complications such as death of embryos are possible during pregnancy, why more research is needed concerning artemisinin safety in first trimester of pregnancy. However, evaluating the risk of artemisinin in pregnancy is referred as complex, when numerous factors could contribute to e.g. fetal loss, abnormalities, or wrong medication. Cultural and economical aspects have to be considered when designing a monitoring system, to enable effective registration of drug quality and drug intake, and follow-up study of mother and child. Accessibility, affordability, possibility and knowledge, are other significant related aspects that have to be managed to eliminate the risk of artemisinin in early pregnancy.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 180-194). Available also in a digital version from Dissertation Abstracts.

Mycotoxin contamination in food commodities is an age-old problem. Due to the detrimental impact of mycotoxins on human health, exposure to mycotoxins and their health implications have been increasingly recognized. Ochratoxin A (OTA), one of the mycotoxins, has been found to cause diverse toxicities in animals, with potential impact on human health. OTA has been reported to be teratogenic and interfere with steroidogenesis in vivo. Chronic exposure of pregnant women to OTA may be hazardous for the human foetus, especially when endocrine and developmental toxicities are taken into consideration. Accordingly, in the first part of this project, I hypothesized that OTA may interfere with enzymes involved in human placental steroidogenesis. By evaluation of human placental 3β–hydroxysteroid dehydrogenase/isomerase (3β-HSD) at both mRNA and protein (hormonal) levels, my results showed that OTA could up-regulate 3β-HSD1 expression in human placental cells with concentration relevant to human exposure. This study is the first to report the endocrine disruption potential of OTA in human placental cells. As several mycotoxins have been demonstrated previously to cross human placental barrier and OTA has been associated with developmental toxicity in vivo, I further hypothesized that OTA may be transferred through human placenta and accumulate in foetal compartment. In the second part of this project, human perfused placenta was used to investigate the placental toxicokinetics of OTA using concentrations found in serum of pregnant women. Findings from this study clearly showed that the transfer of OTA through term human placenta was minimal, contradicting the existing epidemiological studies reporting higher foetal OTA levels than maternal. This is the first study where transplacental kinetics of OTA has been studied in human perfused placenta. To assess the relevance of the study findings, it is very important to provide information on maternal OTA exposure during pregnancy. Currently there is limited information regarding OTA exposure of pregnant women. The third part of this project aimed at evaluating the frequency and level of exposure to OTA in pregnant women from Egypt, where exposure to dietary mycotoxins is common due to the environmental conditions. Biomonitoring of both serum and urinary OTA levels showed that more than 70% of pregnant women were exposed to OTA with a geometric mean of 0.27 ng/ml in serum and 37.21 pg/mg creatinine in urine indicating frequent exposure of this subpopulation. As an ultimate aim, maternal-foetal risk assessment served as a conclusive part of this project to predict and evaluate both maternal and foetal risk of exposure to OTA during pregnancy. Data from the exposure of pregnant women in Egypt to OTA were further ultilized to conduct maternal-foetal risk assessment in relation to OTA exposure. Based on the refined Klaassen equation for exposure estimation during pregnancy and the benchmark dose approach for risk assessment, this subpopulation of pregnant women generally was not exposed to OTA in a high-risk manner. However, considering the suspected chronic exposure beginning from early pregnancy with high foetal susceptibility and diverse toxic effects, and in particular the potential endocrine disruption of OTA, keeping OTA exposure to a minimum is recommended. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Infectious disease continues to cause significant problems on reproductive efficiency in the cattle industry. The purpose of this project is to evaluate new testing strategies for Tritrichomonas foetus and Campylobacter fetus subsp. venerealis. This thesis describes the result of three studies that evaluated the use of real-time PCR for the identification of Tritrichomonas foetus and Campylobacter fetus subsp. venerealis in carrier bulls. The first study evaluated the specificity of a real-time PCR test for T. foetus in individual culture enriched samples, and the sensitivity of the assay for use in pooled samples of up to 25 bulls. Specificity estimates were 98.8% (95% CI 97-99.4) and 100% (95% CI 98.9-100) for culture and real-time PCR, respectively. The sensitivity of the real-time PCR assay for pooled preputial samples was: 96.8% (83.8-99.4) for pool ratios 1/3 and 1/5; 93.5% (79.3-98.2) for pool ratios 1/2, 1/15, 1/20 and 1/25; and 90.3% (75.1-96.6), and were not significantly different. However, 13 of the 217 pools tested were negative and 9 of these negative testing pools contained the same positive sample. The media in this positive sample showed evidence of contamination and could potentially explain the failure to detect T. foetus. The second study evaluated the sensitivity of a real-time PCR for the detection of T. foetus in individual and pooled direct preputial samples. Sensitivity of individual samples tested by culture, real-time PCR in direct and culture enriched samples were determined from 121 samples obtained from 9 infected bulls. Sensitivity estimates were: 95.0% (95% CI: 89.6% to 97.7%) for culture, 95.9% (95% CI: 90.7 to 98.2) for real-time PCR in cultured enriched samples, and 90.1% (95% CI: 83.5 to 94.2) for direct preputial samples and did not differ (P=0.12). Sensitivity estimates for direct pooled samples in groups of 5 or 10 were: 83.6% (95% CI: 75.6 to 89.4) and 77.3% (95% CI: 68.6-84.1), respectively and were not significantly different (P=0.08). The use of repeat sampling tested in pools by real-time PCR increased the sensitivity to 100% and 96% for 3 consecutive samples (pools of 5 or 10, respectively). The use of pooled direct preputial samples although sensitive, still requires the use of repeated sampling. The third study determined the sensitivity and specificity of a recently developed real-time PCR (qPCR) tests for Cfv. A total of 300 virgin bulls were tested by both culture and qPCR. Specificity estimates were 85% (95% CI: 80.5 to 88.6) for qPCR and 100% (95% CI: 98.7 to 100) for culture, and were significantly different (P<0.01). A total of 4 naturally infected bulls and 9 artificially infected bulls were sampled serially to obtain positive samples for a sensitivity analysis. Sensitivity estimates and 95% confidence intervals are as follows: qPCR (85.4%, 95% CI: 80.6-89.2); direct culture on blood agar (82.3%, 95% CI: 77.2-86.5), DFAT (72.1%, 95% CI: 66.2-77.4), direct culture on Skirrow agar (32.7%, 95% CI: 27.2-38.7), TEM and blood agar (30%, 95% CI: 23.4-37.5), and TEM and Skirrow agar (38.1%, 95% CI: 31-45.9). The sensitivity of the different tests evaluated varied significantly with different ambient temperatures (P<0.01). The sensitivity of the qPCR was significantly higher than any other test when temperatures exceeded 5°C. The use of repeated sampling at weekly intervals significantly improved the sensitivity of the qPCR. The real-time PCR assay for the detection of T. foetus in both individual and pooled samples appears to be highly sensitive and specific. Moreover, the possibility of using direct preputial samples provides a cost-effective diagnostic strategy. Real-time PCR in direct preputial samples for BGC diagnosis in bulls has good sensitivity and specificity. However, the use of repeated sampling maybe needed in order to maximize the ability to detect carrier bulls.

No description available.

I tested a prevalent assumption in glucocorticoid research that states that each species has a dominant glucocorticoid, and cortisol and corticosterone are interchangeable steroids. A comprehensive analysis of historical and current data failed to support this assumption and revealed evidence of drift away from exploration of cortisol and corticosterone as dual, important adrenal products to the exclusive quantification of one, dominant glucocorticoid. Originating approximately 30 years ago, the dominant glucocorticoid/ interchangeability assumption is now portrayed in textbook images used to represent adrenal steroid biosynthesis and is widespread throughout empirical research. Less than 1% of over 50,000 published papers relating to the glucocorticoids have considered the potential for independence in glucocorticoid signaling by quantifying both cortisol and corticosterone within a sample. A dispersed literature shows independent regulation of cortisol and corticosterone, extensive inter-species variation in glucocorticoid concentrations and cortisol: corticosterone ratios and adrenal synthesis of the non-dominant glucocorticoid during early development. We hypothesize that there is a functional duality in glucocorticoid signaling and use mass spectrometry to explore the glucocorticoid profile of the full-term human (n = 125) and guinea pig (n = 28) fetus (both cortisol-dominant species). The sample preparation method yielded poor steroid recoveries (~ 4-28%), which made quantification by mass spectrometry challenging, but in both species corticosterone concentrations were significantly higher in fetal blood compared to umbilical venous or umbilical mixed blood (p < 0.0001), suggesting fetal corticosterone enrichment. Within an individual, cortisol was not an accurate predictor of corticosterone for either species (human, r = 0.001, p > 0.05; guinea pig, r = 0.14, p > 0.05) and our data suggests independent glucocorticoid responses; in humans, cortisol was significantly higher in vaginal deliveries relative to elective Caesarian sections (p < 0.0001) but corticosterone was unaffected. Guinea pig fetal corticosterone was not affected by daily maternal stress during gestation but cortisol was significantly lower in stressed fetuses (p < 0.05). While these preliminary data require further investigation, we conclude that fetuses from the human and guinea pig actively secrete the non-dominant glucocorticoid in late gestation and suggest that there is a functional duality in glucocorticoid signaling. / Thesis (Master, Biology) -- Queen's University, 2010-01-25 10:28:26.307

Term fetuses show differential heart rate responses to their mother’s vs. a female stranger’s voice and newborns show a preference for their mother’s vs. a female stranger’s voice, indicating recognition/learning of the mother’s voice before birth. However, fetal response to the father’s voice is unknown and was examined in this study. Forty mother-fetal pairs and the fathers participated. Parents were audio recorded reading a story. Each fetus was presented with the recordings using the following 3 min periods: pre-voice no-sound, voice (mother or father, counterbalanced over subjects), post-voice no-sound. Following a 20 min delay, the opposite voice was delivered. Voices were presented about 10 cm above the maternal abdomen at an average of 95 dB A; heart rate and body movements were recorded continuously. After delivery, newborn head-turning to three, 20 s trials of each parent’s voice (counter balanced over subjects) delivered at an average of 80 dB A was observed. Results showed that fetuses responded to the mother’s and father’s voices, demonstrating a heart rate increase to both voices compared to no heart rate change during the pre-voice baseline period. Fetuses showed no heart rate response to their mother reading a story but showed a heart rate increase when her audio recording was played. After birth, as newborns, they turned their heads more often towards their mother’s voice and away from their father’s voice. It was concluded that both the mother’s and father’s voice can capture and sustain the fetuses’ attention and that newborns prefer their mother’s vs. their father’s voice. / Thesis (Master, Nursing) -- Queen's University, 2010-09-03 17:23:13.638

Amniotic fluid (AF) is a protective pool and a resource of amino acids for the growing fetus. In study 1, we investigated if any of these AF amino acids at mid gestation were associated with fetal development in humans. Nineteen amino acids differed across birth weight percentiles. Arginine, 3-methyl histidine and tryptophan were positive predictors of birth weight, while ornithine was a negative predictor. In study 2, we used a diet induced model of IUGR to see if specific AF amino acids were predictive of fetal weight near term. Methionine and phenylalanine were modified by diet, and 12 amino acids were independently modified by gestational age, respectively. Cysteine, lysine, methionine and tyrosine were predictors of fetal weight. Thus, the AF amino acid pool is associated in animals and humans with fetal growth.

Using second trimester amniotic fluid (AF), the objectives of this study were two-fold: 1) to investigate the relationship between AF glucose and insulin levels as a predictor of macrosomia and 2) to create a risk profile for macrosomia (LGA> 90th percentile) using a combination of AF glucose and insulin concentrations. Amniotic fluid samples were obtained from non-diabetic women (n = 542) undergoing age-related amniocentesis (12th to 22nd week). AF glucose was quantified using a standard hexokinase assay and AF insulin was quantified using the Beckman Access ultrasensitive assay system. Although LGA infants were found to have significantly higher concentrations of insulin and glucose in their 2nd trimester AF, logistic regressions showed that neither alone predicted the outcome of macrosomia. However, a Bayesian two-dimensional contour map plotted the risk for LGA using both AF glucose and insulin. The two-dimensional contour map illustrated the value in considering AF glucose and insulin together to predict LGA in newborns.