Thesis (M.A.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 51-67). Also available on the Internet.

Thesis (M.A.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 51-67). Also available on the Internet.

Abstract Introduction The degradation of plastic waste into smaller micro- and nanoplastic (MNPs) molecules has led to widespread distribution of these particles and accumulation in the environment, making human exposure inevitable. This can result in, or exacerbate, pathological conditions leading to immune dysfunction, neurodegenerative diseases, and infertility. Yet few studies have examined the effects of nanoplastics (NPs) on human health, especially the reproductive system. Reproductive toxicity of plastic particles has been mostly studied in males with most studies investigating microplastics. Therefore, the present study aims to assess the reproductive health consequences of NPs exposure in females by quantifying serum estradiol and progesterone, examining estrous cyclicity, and assessing ovarian reserve (number and quality of follicles) which is a key indicator of female fertility. Materials & Methods The present study was carried out in female mice (C57BL/6) exposed orally to water (control) or one of two solutions containing different concentrations of Polystyrene nanoplastics (PS-NPs; 100 µg/l or 1000 µg/l in water. Exposure occurred daily for 29 days, and vaginal lavage samples were collected for the last 15 days of the exposure phase to check for change in estrous cyclicity. Mice were euthanized at the end of the study and their blood samples and reproductive tissues were collected. Ovaries were fixed in 10% formalin, embedded in paraffin wax, serially sectioned at 5 µm thickness, and stained with hematoxylin and eosin (H&E) for microscopy and follicle analysis. ELISA was also performed to quantify the progesterone and estradiol serum levels. Results There was a significant increase in the estrous cycle length in the high dose (1000 µg/l) PS-NPs exposure group compared to control (5.53±.25 days vs 4.7±0.23 days, P=0.02). Moreover, there was a significant decrease in serum progesterone levels in the high-dose exposure group compared to control (mean difference=1.64 pg/ml, standard error of difference (SED)=0.64, P=0.03). Additionally, it was shown that PS-NPs exposure significantly reduced antral follicles’ diameter in both the low dose (238.61±19.01 µm vs 167.35±19.01 µm, P=0.03) and high dose exposure groups compared to the control group with the higher dose showing a more pronounced reduction in antral follicle' size (238.61±19.01 µm vs 131.95±19.01 µm, P=0.001). Conclusion Oral PS-NPs exposure in female mice appears to induce toxicity by reducing antral follicles size, increasing the estrous cycle length, and decreasing progesterone levels which may result in anovulation and different reproductive issues, such as infertility and polycystic ovary syndrome (PCOS). The effect of PS-NPs on infertility along with NPs’ mechanism of action in female reproductive system should be investigated in future studies. / Thesis / Master of Science (MSc) / Plastics in the environment break down into smaller particles called micro- and nanoplastics. These plastic particles are pollutants present in the aquatic and terrestrial environments entering every level of the food chain and ultimately reaching humans, yet few studies have examined the effects of nanoplastics on human health. A recent World Health Organization (WHO) report on nanoplastics has stressed the urgent need for toxicological studies to assess potential human health effects. Therefore, this study examined the effect of nanoplastics on the female reproductive system. This study was carried out in female mice exposed orally to a solution containing a vehicle control (water) and two different concentrations of nanoplastics (100 and 1,000 µg/l). Exposure occurred daily for a period of 29 days. At the conclusion of the study the mice were humanly euthanized with their blood and reproductive tissues collected for laboratory analysis. Results showed that nanoplastics exposure resulted in irregular reproductive cycle in mice along with a decrease in antral follicle size and progesterone levels which are indicators of anovulation and can lead to disorders, such as infertility and polycystic ovary syndrome (PCOS) which should be further investigated in future studies.

This study aimed to investigate the effects of commercially available natural (sugar cane molasses, white sugar and brown sugar) and artificial (Canderel™, Equal™, Natreen™, Sweetex™, Splenda™ and Swheet™) sweeteners on various physiological systems. The artificial sweeteners tested in this study may be categorised into their respective groups based on their primary ingredient. The brands Canderel™ and Equal™ contain aspartame, Natreen™ and Sweetex™ consist of saccharin and Splenda™ and Swheet™ are composed of sucralose. The inclusion of artificial or natural sweeteners in the human diet has been continually debated and their implication in the development of certain diseases has raised concern regarding their safe use. Therefore, it is necessary that these food products be subjected to a battery of tests to determine adverse effects on human health.

This study aimed to investigate the effects of commercially available natural (sugar cane molasses, white sugar and brown sugar) and artificial (Canderel™, Equal™, Natreen™, Sweetex™, Splenda™ and Swheet™) sweeteners on various physiological systems. The artificial sweeteners tested in this study may be categorised into their respective groups based on their primary ingredient. The brands Canderel™ and Equal™ contain aspartame, Natreen™ and Sweetex™ consist of saccharin and Splenda™ and Swheet™ are composed of sucralose. The inclusion of artificial or natural sweeteners in the human diet has been continually debated and their implication in the development of certain diseases has raised concern regarding their safe use. Therefore, it is necessary that these food products be subjected to a battery of tests to determine adverse effects on human health.

The study is informed by inadequate information on factors associated with the prevalence, incidence and mortality of cervical cancer cytological abnormalities in Swaziland. The aim of the study was to explore and describe factors associated with cervical cancer among women of reproductive age between 15 and 49 years in Swaziland. Quantitative descriptive design with a data extraction tool was used to retrospectively generate observational data from 1748 patients’ records in Mbabane Government Hospital from January 2014 through to December 2014. Bivariate logistic regression was used to establish relationship between cervical cancer and each explanatory variable. The overall prevalence of cervical cytology test results was 24.9%. The combination of marital status, HIV status, ART status, age at sexual debut have been identified as factors associated with cervical abnormalities. Most importantly, the results will also serve as evidence for the development of a national cervical cancer screening policy and also strengthening the cancer registry in Swaziland. / Health Studies / M.A. (Public Health)

The purpose of this study was to explore and describe contributing factors that influence the perceptions of women with fibroids from diverse cultures regarding hysterectomy. The area of research was delimited to issues of hysterectomy among women with fibroid uterus. The study employed a descriptive explorative method and data were collected by means of structured questionnaires. The study was conducted in one academic referral hospital, over a period of six months. The respondents were the patients with fibroid uterus and the doctors and nurses in the gynaecological units of the hospital. The majority of the patients indicated that they were afraid of undergoing a hysterectomy because of the social stigma associated with this life-saving procedure, such as alienation or marginalization by members of their respective communities. The nursing staff and gynaecologists in the unit emphasized the deep-seated fear of hysterectomy amongst women from diverse cultures. The study found that women need information about their bodies and how they function. Health education is also needed for women and their communities. Research is needed amongst members of different communities and diverse cultures to voice their perceptions of women undergoing hysterectomy because of ill health. / Health Studies / M.A. (Health studies)

The purpose of this study was to explore and describe contributing factors that influence the perceptions of women with fibroids from diverse cultures regarding hysterectomy. The area of research was delimited to issues of hysterectomy among women with fibroid uterus. The study employed a descriptive explorative method and data were collected by means of structured questionnaires. The study was conducted in one academic referral hospital, over a period of six months. The respondents were the patients with fibroid uterus and the doctors and nurses in the gynaecological units of the hospital. The majority of the patients indicated that they were afraid of undergoing a hysterectomy because of the social stigma associated with this life-saving procedure, such as alienation or marginalization by members of their respective communities. The nursing staff and gynaecologists in the unit emphasized the deep-seated fear of hysterectomy amongst women from diverse cultures. The study found that women need information about their bodies and how they function. Health education is also needed for women and their communities. Research is needed amongst members of different communities and diverse cultures to voice their perceptions of women undergoing hysterectomy because of ill health. / Health Studies / M.A. (Health studies)