Dissertations / Theses on the topic 'Sheep Fetuses'
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1
Pfister, Riccardo E. (Riccardo Erennio) 1961. "Control of lung liquid throughout late gestation and labour." Monash University, Ritchie Centre for Baby Health Research, 2001. http://arrow.monash.edu.au/hdl/1959.1/9321.
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Boland, Rochelle Elizabeth 1974. "Factors affecting structural development of the lung in fetal sheep." Monash University, Dept. of Physiology, 2002. http://arrow.monash.edu.au/hdl/1959.1/8135.
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Chidzanja, Stivelia. "Restricted implantation and undernutrition alter development and growth of the ovine placenta." Title page, abstract and contents only, 1994. http://hdl.handle.net/2440/18519.
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Bibliography: 161-199.[xxvi], 199, [151] leaves, [7] leaves of plates : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Characterises the normal otogeny of the cellular composition and structure of placentomes in sheep, their relationship to the macroscopic parameters of placentome size and morphology, and the effect of experimental and natural restriction of implantation on the growth and development of placentomes between mid and late gestation.
Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1995
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Kakar, Muhammad Azam. "Effect of peri-conceptional feed intake on early embryo development and fetal growth in the Merino ewe /." Title page, table of contents and abstract only, 2003. http://web4.library.adelaide.edu.au/theses/09ANP/09anpk138.pdf.
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Yan, Ping. "Changes in fetal egg and blood pressure in normally grown and chronic placental embolization fetal sheep during graded cord occlusions." Thesis, The University of Sydney, 2003. https://hdl.handle.net/2123/27957.
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The fetal electrocardiogram (FECG) has been considered a potentially useful tool for fetal surveillance during birth as technical improvements in signal acquisition and processing have been achieved. The aim of the thesis is to determine the ability of the changes in fetal ECG morphological characteristics and time intervals (FI-IR, PR interval, T/QRS, and R height) to predict fetal hypoxemia /acidemia and relationships between these parameters of FECG and fetal blood pressure.
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Butler, Timothy Garth. "Functional heterogeneity of the corticotroph cells in the fetal sheep pituitary /." Title page, table of contents and summary only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phb9851.pdf.
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Kind, Karen Lee. "Insulin-like growth factors and growth of the fetal sheep /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phk525.pdf.
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Ross, Jacob T. "Hypophysial and local mediators of adrenocortical growth and function before birth /." Title page, contents and summary only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phr8242.pdf.
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Joyce, Belinda Jane. "Elastin synthesis in the fetal sheep lung in vivo : effects of physical, metabolic and endocrine factors." Monash University, Dept. of Physiology, 2004. http://arrow.monash.edu.au/hdl/1959.1/5263.
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Meyer, Amanda Jane. "The impact of prenatal glucocorticoid exposure on the ovine kidney." University of Western Australia. School of Women's and Infants' Health, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0105.
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[Truncated abstract] In obstetric practice, pregnant women at risk of pre-term delivery between 24 and 34 weeks of gestation are administered synthetic glucocorticoids (betamethasone or dexamethasone) to induce fetal organ maturation. During this gestational period, the fetal kidney is undergoing a phase of rapid organogenesis with an increase in renal growth and active nephrogenesis occurring. The studies comprising this thesis examine the effects of prenatal betamethasone exposure on the fetal and adult ovine kidney. The central hypothesis of these studies was that exposure of the fetal kidney to betamethasone in late gestation would change renal structure and induce long-term alterations in the expression of glucocorticoid-sensitive genes and proteins. In the fetal studies, pregnant Merino ewes bearing single fetuses received single or repeated-weekly intra-muscular (i.m.) injections of betamethasone (0.5 mg/kg body weight) or saline commencing on day 104 of gestation (term is 150 days). Kidneys were collected from fetuses at 109, 116, 121 and 146 days of gestation (d). Using gold standard unbiased stereological techniques, the physical disector/fractionator method, total glomerular (nephron) number and glomerular volume were determined in 146 d fetal kidneys exposed to repeated maternal saline or betamethasone administration. In the adult study, kidneys were collected from 3.5-year-old sheep that had been exposed to ... In this thesis I have demonstrated that renal growth restriction as a result of betamethasone exposure is associated with a reduction in fetal nephron endowment. Although betamethasone does not appear to consistently alter nephron number or glomerular size, it may indirectly affect total nephron endowment through effects on renal growth. I have also provided evidence which suggests that lategestation betamethasone exposure in sheep does not program permanent alterations in the renal expression of genes or proteins involved in glucocorticoid hormone action or components of the renin-angiotensin system. Therefore, exposure of the fetal kidney to betamethasone during nephrogenesis may alter renal structure if kidney growth is perturbed; however, there are no persistent alterations in the expression of glucocorticoid-sensitive genes. These findings are consistent with the preservation of normal basal blood pressure in the adult sheep I studied and with the limited results from human studies of late-gestation maternal glucocorticoid administration.
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David, A. L. M. "Development of ultrasound-guided gene therapy to the sheep fetus." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444686/.
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Fetal gene therapy may treat genetic diseases before significant organ damage, target stem cell populations and avoid immune sensitisation. Candidate diseases include cystic fibrosis, haemophilia and lysosomal storage disorders. This thesis developed ultrasound-guided delivery of viral vectors to the sheep fetus for treatment of these diseases. For haemophilia B treatment we delivered adenovirus vectors containing the p-galactosidase reporter gene (adlacZ) or the human factor IX gene (adhFIX) by ultrasound guidance to the early gestation sheep fetus, when it is considered to be pre-immune. Intraperitoneal injection allowed the earliest time point for gene delivery, achieved the highest hFIX levels and the most localised p-galactosidase expression. Therapeutic hFIX levels were detected after intramuscular and intra-amniotic delivery suggesting that these are potentially alternative sites for therapeutic gene expression. For each route examined, no humoral immune response was observed to the transgene, although antibodies to the adenovirus vector were identified. We achieved intravascular delivery via umbilical vein injection therapeutic hFIX levels were detected. We developed ultrasound-guided transthoracic injection of the mid-gestation fetal trachea for cystic fibrosis treatment, p-galactosidase expression, measured by ELISA, was low after delivery of adlacZ vector alone, but increased 10 fold when the vector was complexed with DEAE dextran. Pretreatment of the fetal airways with sodium caprate increased expression by 90 fold the effect of the two agents was synergistic. Perflubron instillation following vector injection redistributed transgene expression from the large to the small airways. We developed ultrasound-guided fetal intragastric injection and achieved widespread transgene expression throughout the gastrointestinal epithelia after adlacZ vector delivery. For brain manifestation of lysosomal storage disorders we injected adlacZ vectors to the fetal ventricles under ultrasound guidance. Transduction of the choroid plexus was seen. Future application of integrating vectors such as lentivirus may allow for long term therapeutic correction and induce immune tolerance to the transgene.
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Koch, Jill Marie. "Periconceptional treatment with growth hormone alters fetal growth and development in sheep." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5713.
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Thesis (Ph. D.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains ix, 128 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Gilbert, Jeffrey Stephen. "Cardiorenal adaptations of the ovine fetus and offspring to maternal nutrient restriction." Laramie, Wyo. : University of Wyoming, 2005. http://proquest.umi.com/pqdweb?did=1044392391&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Marrocco, Esther Ruth. "The effect of glucose infusion on adiposity and leptin secretion in the late gestation sheep fetus /." Title page and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09SB/09sbm361.pdf.
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Yunusova, Roza. "Effects of Maternal Nutrition, Intrauterine Growth Restriction (IUGR), and Estrogen (E2) Supplementation on Placental and Fetal Intestinal Growth and Development in Sheep." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26539.
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The placenta and fetal intestines are two key nutrient transport organs that sustain and nurture growing fetus. Insufficient placental development and consequently inadequate fetal nutrient supply can lead to IUGR resulting in low birth weight offspring. Our experimental objectives were to investigate the effects of elevated maternal nutrition, IUGR, and E2 supplementation during mid-gestation (in an attempt to rescue IUGR offspring) on placental and fetal intestinal cell proliferation, angiogenic gene expression, and vascularity. Limited responsiveness in placental development and vascularization to E2 supplementation was observed, likely due to inappropriate timing or dose of E2. However, maternal E2 supplementation increased fetal small intestinal length and GUCY1b3 mRNA expression, suggesting that E2 supplementation has positive effects on IUGR fetal intestinal growth. In conclusion, understanding molecular mechanisms associated with IUGR and possible effects of E2 supplementation in rescuing IUGR may lead to enhanced human health and livestock production efficiency.
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Chia, Philip H. Y. "The role of glucose and insulin upon the hypothalamic-pituitary axis in the late gestation sheep fetus /." Title page and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09SB/09sbc532.pdf.
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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Physiology, 1999?Spine title: Interaction of insulin and glucose on the fetal HPA axis. Includes bibliographical references (leaves 21-24).
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Spencer, Timothy N. "Developmental changes in contractile properties of the right ventricular papillary muscle in the late gestational sheep fetus /." Title page and abstract only, 2005. http://web4.library.adelaide.edu.au/theses/09SB/09sbs7451.pdf.
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Carr, D. "Evaluation of prenatal adenoviral vascular endothelial growth factor gene therapy in the growth-restricted sheep fetus and neonate." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1401185/.
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Background - Fetal growth restriction (FGR) is associated with reduced uterine blood flow (UBF). In normal sheep pregnancies, adenovirus (Ad) mediated over-expression of vascular endothelial growth factor (VEGF) in the uterine arteries (UtA) increases UBF. It was hypothesised that enhancing UBF would improve fetal substrate delivery in an ovine paradigm of FGR characterised by reduced UBF from mid-gestation. Methods - Singleton pregnancies were established using embryo transfer in adolescent ewes subsequently overnourished to generate FGR (n=81). Ewes were randomised mid-gestation to receive bilateral UtA injections of 5x1011 particles Ad.VEGF-A165 or inactive treatment (saline or 5x1011 particles Ad.LacZ, a control vector). Fetal growth/wellbeing were evaluated using serial ultrasound. Late-gestation study: UBF was monitored using indwelling flowprobes until necropsy at 0.9 gestation. Vasorelaxation, neovascularisation in perivascular adventitia and placental mRNA expression of angiogenic factors/receptors were examined. A group of control-fed ewes with normally-developing fetuses was included (n=12). Postnatal study: Pregnancies continued until spontaneous delivery near to term. Lambs were weighed and measured weekly and underwent metabolic challenge at 7 weeks, dual-energy X-ray absorptiometry at 11 weeks, and necropsy at 12 weeks postnatal age. DNA methylation of somatotropic genes was examined in hepatic tissues. Results - Ultrasonographic fetal growth velocity was greater in Ad.VEGF-A165-treated versus control-treated FGR fetuses at 3-4 weeks post-injection. In late gestation fewer fetuses were markedly growth-restricted following Ad.VEGF-A165 therapy. There was evidence of mitigated brain sparing. No effect was seen on UBF/neovascularisation although Ad.VEGF-A165-transduced vessels showed enhanced vasorelaxation. Flt1/KDR expression was increased in the maternal placental compartment. At birth Ad.VEGF-A165-treated lambs tended to be heavier with increased placental efficiency. Postnatal growth, lean tissue accretion and insulin secretion were also increased, however no epigenetic changes were observed. Conclusions - Ad.VEGF-A165 safely increases fetal growth in this ovine model of FGR. This work has supported a successful application to translate this therapy into the clinic.
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Liang, Rongti. "Molecular cloning and characterization of the ovine placental lactogen gene /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9717169.
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Erkinaro, T. (Tiina). "Fetal and placental haemodynamic responses to hypoxaemia, maternal hypotension and vasopressor therapy in a chronic sheep model." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514281659.
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Knowledge of the effects of maternally administered vasopressors on human fetal and placental haemodynamics is sparse and limited to elective Caesarean deliveries in uncomplicated pregnancies. We hypothesized that, after short-term fetal hypoxaemia, which activates fetal cardiovascular compensatory mechanisms, treatment of maternal hypotension with ephedrine or phenylephrine results in divergent responses in fetal and placental haemodynamics.
Chronically instrumented near-term sheep fetuses with either normal placental function or increased placental vascular resistance following placental embolization were exposed to two subsequent periods of decreased fetal oxygenation caused by maternal hypoxaemia and epidural-induced hypotension. The fetuses that underwent placental embolization were also chronically hypoxaemic.
Fetal and placental haemodynamics were assessed by invasive techniques and by noninvasive Doppler ultrasonography. Our results show that umbilical artery blood flow velocity waveforms cannot be used to derive information of fetal cardiac function. Furthermore, the changes in placental volume blood flows and vascular resistances caused by maternal vasopressor treatment cannot be reliably recognized based on uterine and umbilical artery pulsatility index values.
In response to acute hypoxaemia, a fetus with normal placental function redistributes its right ventricular cardiac output from the pulmonary to the systemic circulation and is able to increase its combined cardiac output, with a concomitant relative decrease in the net forward flow through the aortic isthmus. However, fetal haemodynamic responses to subsequent hypoxaemic insults may vary. Furthermore, the compensatory responses of fetuses with increased placental vascular resistance differ from those of normal fetuses. In these fetuses, repeated episodes of a further decrease in oxygenation lead to lactataemia.
The effects of ephedrine on uteroplacental and umbilicoplacental circulations were more favourable than those of phenylephrine. Ephedrine restored the changes in fetal cardiovascular haemodynamics caused by maternal hypotension to the baseline conditions in both embolized and nonembolized fetuses. Phenylephrine did not reverse fetal pulmonary vasoconstriction or the relative decrease in the net forward flow through the aortic isthmus. Moreover, fetal left ventricular function was impaired by phenylephrine. Although no significant differences in fetal acid-base status were observed in fetuses with normal placental function, the lactate concentrations of the embolized fetuses increased further when maternal hypotension was treated with phenylephrine.
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O???Connell, Amanda Elizabeth School of Medical Science UNSW. "Consequences of an altered intrauterine environment on the offspring???s renal, cardiovascular and renin angiotensin systems." Awarded by:University of New South Wales. School of Medical Science, 2006. http://handle.unsw.edu.au/1959.4/26320.
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This thesis reports the effects of an altered intrauterine environment on the offspring???s renal, cardiovascular and renin angiotensin systems. After a midgestational asphyxial episode in fetal sheep (30 min total umbilical cord occlusion at 90 days; term 150 days) the hydrops that resulted had not completely resolved by 130 days. While the heart and kidneys were apparently unaffected, the brain and lung weights were 37% and 50% lower than sham values, respectively and there were joint contractures. The effects of maternal renal disease on the offspring were investigated. Although in utero fetuses of subtotally nephrectomised ewes (STNx) had altered urine flow rates, sodium excretion, haematocrits, plasma chloride and plasma renin levels, by 1-2 weeks after birth these values in the lambs (STNxL) were similar to controls (ConL) under baseline conditions. Body weight and the weights of most organs were similar, including the kidney, in which glomerular number was normal. In the neonatal period, the lambs were subjected to four challenges: furosemide (2 mg/kg intravenous bolus), infusion of angiotensin II and phenylephrine, intravenous infusion of 0.15M saline (50 ml/kg over 30 min) and haemorrhage (20% estimated blood volume over 10 min). These challenges revealed evidence of programming of several aspects of the renal, cardiovascular and renin angiotensin systems in the STNx offspring. As young adults at 6 months of age, male and female offspring of STNx ewes were normotensive and had normal renal function. On a high salt diet (HSD, 0.17M NaCl in 8L water for 5-7days), female offspring of both groups did not become hypertensive. However, the STNx offspring must have retained salt and water as plasma sodium was increased and haematocrit was decreased. In the STNx offspring only, there was a relationship between glomerular filtration rate (GFR) and mean arterial pressure, indicating an inability to maintain a constant GFR in response to changes in arterial pressure.
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Garabedian, Charles. "Développement d’un nouvel indice reflet du bien être fœtal : le Fetal Stress Index." Thesis, Lille 2, 2017. http://www.theses.fr/2017LIL2S022/document.
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La surveillance du bien-être fœtal pendant le travail repose essentiellement sur l’enregistrement du rythme cardiaque fœtal (RCF). Celui-ci, même continu pendant le travail, ne permet pas d’évaluer parfaitement l’oxygénation du fœtus ni le risque d’asphyxie néonatale. En effet, cet outil est imparfait et son évaluation subjective avec une importante variabilité d’interprétation inter et intra opérateur. Des examens dits de seconde ligne sont utilisés en pratique courante pour caractériser l’état fœtal : le prélèvement de sang fœtal au scalp pour l’étude de l’équilibre acido-basique du fœtus (pH ou lactates) ou la pose d’électrode au scalp pour étudier l’ECG fœtal (analyse du segment ST). Ces techniques sont néanmoins invasives et sont soumises à des contraintes techniques. Il y a donc un intérêt à développer des moyens d’évaluation du bien être fœtal à la fois objectifs et non invasifs afin de diminuer la survenue d’une asphyxie périnatale. En effet, celle-ci touche 3 à 8 nouveaux nés pour 1000 naissances. La mortalité en période post-natale est de 25 à 50% des cas et ceux qui survivent développeront des troubles sévères (épilepsie, retard neuro-cognitif et comportemental, paralysie cérébrale…). Au cours de l’accouchement, l’asphyxie périnatale se caractérise par une diminution du pH artériel ombilical. Cette mesure du pH sanguin est donc la mesure de référence pour déterminer la sévérité de l’asphyxie.Une des voies étudiées pour améliorer le dépistage des fœtus à risque d’acidose est l’analyse des modifications du système nerveux autonome (SNA) par analyse de la variabilité du rythme cardiaque fœtal. En effet, la fréquence cardiaque fœtale est en permanence sous l’influence du système nerveux autonome et sa variabilité (VFC) est un reflet de la balance sympathique / parasympathique. Le CHU de Lille a développé une nouvelle méthode d’analyse continue de la VFC ayant montré son efficacité chez l’adulte et chez le nouveau né pour l’évaluation du SNA. L’objectif de ce travail de Thèse est d’adapter cette technologie à l’analyse du SNA fœtal pour obtenir un nouvel indice appelé Fetal Stress Index (FSI) et d’évaluer sa pertinence en situation d’acidose.Cette preuve de concept a été effectuée de manière expérimentale chez le fœtus de brebis. Elle s’est réalisée en 2 temps. Nous avons tout d’abord évalué la performance du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes d’aptitude à détecter les variations du SNA. Après injection d’Atropine, parasympatholytique, ou de Propranolol, sympatholytique, nous avons montré que le FSI était une méthode efficace et spécifique d’évaluation des variations du tonus parasympathique du SNA. Cette étude a également montrée la supériorité du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes de sensibilité et de spécificité. Dans un second temps, nous avons évalué ce nouvel indice comme facteur prédictif de l’état acido basique du fœtus dans 2 modèles expérimentaux d’occlusion cordonale. Dans le premier modèle, l’acidose était obtenue par une occlusion continue du cordon avec une réduction de partielle du débit ombilical. Dans le second, nous réalisions des occlusions totales répétées à intervalles réguliers afin de mimer les contractions utérines lors du travail. Dans les 2 études, nous avons observé une hausse du FSI en cas d’acidose avec une corrélation significative entre le FSI et le pH, mais aussi entre le FSI et les lactates dans le second modèle.En conclusion, le FSI constitue un bon reflet de l’activité parasympathique fœtale. Cet indice permet d’étudier les variations du SNA fœtal avec une meilleure sensibilité et une meilleure spécificité que les méthodes usuelles d’analyse de la VFC et semble bien corrélé à l’état acido basique fœtal. Il s’agit donc d’un indice prometteur qu’il sera intéressant d’incorporer dans une analyse multi paramétrique du rythme cardiaque fœtalThe monitoring of fetal well being during labor is essentially based on fetal heart rate (FHR) analysis. The recording of FHR, even continuously during labor, does not fully assess fetal oxygenation or neonatal risk of asphyxia. Indeed, this tool is imperfect and subjective with an important inter and intra-operator variability. Second-line examinations to characterize the fetal state are currently used in routine practice, i.e. scalp fetal blood sampling to study the fetal acid-base balance (pH or lactates) or scalp electrode placement to study the fetal ECG (ST segment analysis). These techniques are nevertheless invasive and subject to technical constraints. There is therefore an interest in developing both objective and non-invasive means of evaluating fetal wellbeing to reduce neonatal encephalopathy. Indeed, its prevalence is about 3 to 8 per 1000 births. Post natal mortality is about 25 to 50% and survivors will hav severe diseases (epilepsy, neurologic impairment, cerebral palsy…).One of the possibilities studied to better identify fetuses at risk for acidosis is the analysis of changes in the autonomic nervous system (ANS) in response to hypoxia.Indeed, the regulation of heart rate is dependent on the ANS and thus, its variability is a reflection of the sympathetic / parasympathetic balance. Analysis of heart rate variability (HRV) is a recognized non-invasive tool that is used to assess ANS regulation. The CHU Lille has developed a new continuous tool for the analysis of HRV, which demonstrated its efficacity in adults and neonates to evaluate the ANS. The objective of this thesis was to develop its index, called Fetal Stress Index (FSI), in the fetus and to evaluate it in conditions of acidosis.The study was experimental in a sheep model chronically instrumented and was in 2 steps. First, we evaluate the performance of our method compared to commonly used HRV analysis, regarding the ability to detect the variation of variations of the ANS. After injection of atropine, to inhibit parasympathetic tone, or propranolol to block sympathetic activity, we shown that our method appeared to be effective in detecting parasympathetic inhibition and, moreover, was superior to classical analysis of HRV in terms of sensibility and specificity.In a second time, we evaluated this new index as a predictive factor of the fetal acid-base state in 2 experimental models of fetal hypoxia by occlusion of the cord. In the first one, acidosis was obtained through a partial occlusion of the umbilical cord and in the second one, though repetitive complete occlusion as uterine contractions during labor. In those two studies, we observed a raise of our index in case of acidosis with a correlation beetween FSI and pH and also FSI and lactates in the second model.In conclusion, the FSI reflects fetal parasympathetic activity, has a better detection than others usual methods, and seems well correlated to fetal acid-base status. It is a promising index and it will be interesting to incorporate it in a multi parametric analysis of fetal heart rate to predict acidosis
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Dando, Samantha Joan. "Ureaplasma parvum : understanding the complexities of intra-amniotic infection in an ovine model." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/50958/1/Samantha_Dando_Thesis.pdf.
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The human Ureaplasma species are the most frequently isolated bacteria from the upper genital tract of pregnant women and can cause clinically asymptomatic, intra-uterine infections, which are difficult to treat with antimicrobials. Ureaplasma infection of the upper genital tract during pregnancy has been associated with numerous adverse outcomes including preterm birth, chorioamnionitis and neonatal respiratory diseases. The mechanisms by which ureaplasmas are able to chronically colonise the amniotic fluid and avoid eradication by (i) the host immune response and (ii) maternally-administered antimicrobials, remain virtually unexplored. To address this gap within the literature, this study investigated potential mechanisms by which ureaplasmas are able to cause chronic, intra-amniotic infections in an established ovine model.
In this PhD program of research the effectiveness of standard, maternal erythromycin for the treatment of chronic, intra-amniotic ureaplasma infections was evaluated. At 55 days of gestation pregnant ewes received an intra-amniotic injection of either: a clinical Ureaplasma parvum serovar 3 isolate that was sensitive to macrolide antibiotics (n = 16); or 10B medium (n = 16). At 100 days of gestation, ewes were then randomised to receive either maternal erythromycin treatment (30 mg/kg/day for four days) or no treatment. Ureaplasmas were isolated from amniotic fluid, chorioamnion, umbilical cord and fetal lung specimens, which were collected at the time of preterm delivery of the fetus (125 days of gestation). Surprisingly, the numbers of ureaplasmas colonising the amniotic fluid and fetal tissues were not different between experimentally-infected animals that received erythromycin treatment or infected animals that did not receive treatment (p > 0.05), nor were there any differences in fetal inflammation and histological chorioamnionitis between these groups (p > 0.05). These data demonstrate the inability of maternal erythromycin to eradicate intra-uterine ureaplasma infections. Erythromycin was detected in the amniotic fluid of animals that received antimicrobial treatment (but not in those that did not receive treatment) by liquid chromatography-mass spectrometry; however, the concentrations were below therapeutic levels (<10 – 76 ng/mL). These findings indicate that the ineffectiveness of standard, maternal erythromycin treatment of intra-amniotic ureaplasma infections may be due to the poor placental transfer of this drug.
Subsequently, the phenotypic and genotypic characteristics of ureaplasmas isolated from the amniotic fluid and chorioamnion of pregnant sheep after chronic, intra-amniotic infection and low-level exposure to erythromycin were investigated. At 55 days of gestation twelve pregnant ewes received an intra-amniotic injection of a clinical U. parvum serovar 3 isolate, which was sensitive to macrolide antibiotics. At 100 days of gestation, ewes received standard maternal erythromycin treatment (30 mg/kg/day for four days, n = 6) or saline (n = 6). Preterm fetuses were surgically delivered at 125 days of gestation and ureaplasmas were cultured from the amniotic fluid and the chorioamnion. The minimum inhibitory concentrations (MICs) of erythromycin, azithromycin and roxithromycin were determined for cultured ureaplasma isolates, and antimicrobial susceptibilities were different between ureaplasmas isolated from the amniotic fluid (MIC range = 0.08 – 1.0 mg/L) and chorioamnion (MIC range = 0.06 – 5.33 mg/L). However, the increased resistance to macrolide antibiotics observed in chorioamnion ureaplasma isolates occurred independently of exposure to erythromycin in vivo. Remarkably, domain V of the 23S ribosomal RNA gene (which is the target site of macrolide antimicrobials) of chorioamnion ureaplasmas demonstrated significant variability (125 polymorphisms out of 422 sequenced nucleotides, 29.6%) when compared to the amniotic fluid ureaplasma isolates and the inoculum strain. This sequence variability did not occur as a consequence of exposure to erythromycin, as the nucleotide substitutions were identical between chorioamnion ureaplasmas isolated from different animals, including those that did not receive erythromycin treatment. We propose that these mosaic-like 23S ribosomal RNA gene sequences may represent gene fragments transferred via horizontal gene transfer. The significant differences observed in (i) susceptibility to macrolide antimicrobials and (ii) 23S ribosomal RNA sequences of ureaplasmas isolated from the amniotic fluid and chorioamnion suggests that the anatomical site from which they were isolated may exert selective pressures that alter the socio-microbiological structure of the bacterial population, by selecting for genetic changes and altered antimicrobial susceptibility profiles.
The final experiment for this PhD examined antigenic size variation of the multiple banded antigen (MBA, a surface-exposed lipoprotein and predicted ureaplasmal virulence factor) in chronic, intra-amniotic ureaplasma infections. Previously defined ‘virulent-derived’ and ‘avirulent-derived’ clonal U. parvum serovar 6 isolates (each expressing a single MBA protein) were injected into the amniotic fluid of pregnant ewes (n = 20) at 55 days of gestation, and amniotic fluid was collected by amniocentesis every two weeks until the time of near-term delivery of the fetus (at 140 days of gestation). Both the avirulent and virulent clonal ureaplasma strains generated MBA size variants (ranging in size from 32 – 170 kDa) within the amniotic fluid of pregnant ewes. The mean number of MBA size variants produced within the amniotic fluid was not different between the virulent (mean = 4.2 MBA variants) and avirulent (mean = 4.6 MBA variants) ureaplasma strains (p = 0.87). Intra-amniotic infection with the virulent strain was significantly associated with the presence of meconium-stained amniotic fluid (p = 0.01), which is an indicator of fetal distress in utero. However, the severity of histological chorioamnionitis was not different between the avirulent and virulent groups. We demonstrated that ureaplasmas were able to persist within the amniotic fluid of pregnant sheep for 85 days, despite the host mounting an innate and adaptive immune response. Pro-inflammatory cytokines (interleukin (IL)-1â, IL-6 and IL-8) were elevated within the chorioamnion tissue of pregnant sheep from both the avirulent and virulent treatment groups, and this was significantly associated with the production of anti-ureaplasma IgG antibodies within maternal sera (p < 0.05). These findings suggested that the inability of the host immune response to eradicate ureaplasmas from the amniotic cavity may be due to continual size variation of MBA surface-exposed epitopes.
Taken together, these data confirm that ureaplasmas are able to cause long-term in utero infections in a sheep model, despite standard antimicrobial treatment and the development of a host immune response. The overall findings of this PhD project suggest that ureaplasmas are able to cause chronic, intra-amniotic infections due to (i) the limited placental transfer of erythromycin, which prevents the accumulation of therapeutic concentrations within the amniotic fluid; (ii) the ability of ureaplasmas to undergo rapid selection and genetic variation in vivo, resulting in ureaplasma isolates with variable MICs to macrolide antimicrobials colonising the amniotic fluid and chorioamnion; and (iii) antigenic size variation of the MBA, which may prevent eradication of ureaplasmas by the host immune response and account for differences in neonatal outcomes. The outcomes of this program of study have improved our understanding of the biology and pathogenesis of this highly adapted microorganism.
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Jorio, Aziza. "Dynamique folliculaire comparee pendant la periode prepubere chez deux races s de brebis differant par leur taux d'ovulation : la d'man et la timahdite." Paris 6, 1987. http://www.theses.fr/1987PA066446.
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Cabello, Gérard. "Developpement et importance physiologique de la fonction thyroidienne chez l'agneau pendant la periode perinatale." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2E390.
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Hugh, Andrew Roxburgh. "The immune response to Brucella abortus in the adult and foetal sheep." Phd thesis, 1986. http://hdl.handle.net/1885/142639.
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Gentili, Sheridan. "Regulation of SOCS - 3 expression in fetal sheep tissues." 2006. http://hdl.handle.net/2440/37822.
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The suppressor of cytokine signaling ( SOCS ) proteins have been identified as important regulators of cytokine signaling. SOCS - 3 has been identified as being essential for normal fetal growth and survival, with the null mutation of the socs - 3 gene resulting in embryo death. The specific role of SOCS - 3 in fetal development, however, has yet to be characterized. Therefore, the overall aim of this thesis was to identify and quantify SOCS - 3 mRNA in a range of fetal tissues in the sheep. After identification of SOCS - 3 expression in fetal tissues, we then aimed to determine the ontogenic profile of SOCS - 3 in three key fetal tissues ; the liver, adipose tissue and adrenal gland, and whether SOCS - 3 expression in these tissues was altered after withdrawal and stimulation of prolactin ( PRL ). SOCS - 3 mRNA was found to be differentially expressed in a range of fetal tissues in late gestation and was higher in the fetal liver than in the pancreas, spleen and kidney. SOCS - 3 expression increased throughout gestation in the fetal liver, however, its expression decreased in the fetal adipose tissue and adrenal in late gestation. The pituitary hormone PRL has previously been implicated as a fetal growth factor. In the sheep fetus, PRL receptors are expressed in the fetal liver, adipose tissue and adrenal. We aimed to determine whether PRL plays a role in the maintenance of SOCS - 3 expression in the liver, adipose tissue and adrenal gland in late gestation, and whether SOCS - 3 expression can be regulated by acute PRL stimulation. We have demonstrated that PRL withdrawal suppressed SOCS - 3 expression in the liver, whereas acute PRL stimulation upregulated SOCS - 3 expression in the adrenal. Neither PRL withdrawal nor stimulation had an effect on SOCS - 3 expression in the adipose tissue. In summary, the data presented in this thesis would suggest that SOCS - 3 has tissue specific functions in late gestation. Furthermore, its expression is regulated in a tissue specific manner in response to the withdrawal or acute stimulation by PRL This provides the first evidence to suggest that the fetal liver and adrenal are both sensitive to either chronic or acute changes in plasma PRL concentrations, measured as the suppression or upregulation of SOCS - 3. We speculate that changes in SOCS - 3 mRNA expression relates to the regulation of growth and functional maturation of fetal tissues throughout gestation, and that PRL may represent an important factor which acts to alter SOCS - 3 expression in key fetal tissues.Thesis (Ph.D.)--School of Molecular and Biomedical Science, 2006.
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Chidzanja, Stivelia. "Restricted implantation and undernutrition alter development and growth of the ovine placenta." Thesis, 1994. http://hdl.handle.net/2440/18519.
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Bibliography: 161-199.[xxvi], 199, [151] leaves, [7] leaves of plates : ill. (some col.) ; 30 cm.
Characterises the normal otogeny of the cellular composition and structure of placentomes in sheep, their relationship to the macroscopic parameters of placentome size and morphology, and the effect of experimental and natural restriction of implantation on the growth and development of placentomes between mid and late gestation.
Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1995
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Butler, Timothy Garth. "Functional heterogeneity of the corticotroph cells in the fetal sheep pituitary." Thesis, 2003. http://hdl.handle.net/2440/22122.
Full textAbstract:
Bibliography: leaves 161-189.xx, 189 leaves : ill. ; 30 cm.
The aim of the series of experiments described in this thesis was to investigate the functional characteristics of the subpopulations of the corticotrophs in the fetal pituitary during normal development and after chronic intrauterine stress.
Thesis (Ph.D.) -- University of Adelaide, Dept. of Physiology, 2004
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Woodall, John Paul. "The ontogeny of interferon-gamma (IFN-[gamma]) responses in the fetal lamb." Phd thesis, 2005. http://hdl.handle.net/1885/148799.
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Ross, Jacob T. (Jacob Tavern). "Hypophysial and local mediators of adrenocortical growth and function before birth." 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phr8242.pdf.
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Errata pasted onto back end-paper. Bibliography: leaves 213-246. Describes the interactions among pituitary-derived peptides, intra-adrenal exposure to glucocorticoids and the local adrenal and endocrine IGF axes in the growth and functional activation of the ovine fetal adrenal gland before birth. Also considers the involvement of these systems in the fetal response to chronic stess and intra-uterine growth restriction. Proposes and develops several conceptual models of the control of adrenal growth and function in late-gestation.
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Kind, Karen Lee. "Insulin-like growth factors and growth of the fetal sheep / Karen Lee Kind." Thesis, 1995. http://hdl.handle.net/2440/18526.
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Includes bibliographical references.1 v. (various foliations) : ill. ; 30 cm.
Indicates that retarded fetal growth in sheep, associated with restricted supply of substrates to the fetus, is accompanied by reduced concentrations of insulin-like growth factor I in fetal blood and its decreased production in several major fetal tissues.
Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1995
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Farrand, Kirsten. "Impact of environmental factors on the development of corticotroph subpopulations in the fetal sheep pituitary." 2008. http://hdl.handle.net/2440/58643.
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The prepartum surge in fetal plasma cortisol, essential for the maturation of organs in mammals and the normal timing of parturition in some species, including sheep, may result from an increase in the molar ratio of adrenocorticotropin (ACTH) to pro-opiomelanocortin (POMC) in the fetal circulation. Related to this, the cleavage of POMC to ACTH by the enzyme, prohormone convertase 1 (PC1), may be influenced by corticotrophin releasing hormone (CRH) stimulation. Accumulating evidence suggests that the capacity of individual corticotrophs to process POMC to ACTH may vary and individual corticotrophs are differentially responsive to CRH. It is not known, however, if there are separate corticotroph subpopulations in the fetal sheep pituitary which can be identified by differential colocalisation of POMC, ACTH and the CRH receptor 1, CRHR₁, nor if changes in the relative proportions of such subpopulations play a role in the molecular mechanisms underlying the overall changes in pituitary function described previously during gestation and in response to suboptimal uterine environments. To investigate these hypotheses, it was first necessary to develop novel methods for the simultaneous immunohistochemical labelling of POMC, ACTH and CRHR₁ in individual cells on sections of fetal sheep pituitary. In addition, I developed and validated an automated method to categorise and count individual cells to increase the quantitative power of this study. Pituitary tissue was collected from control fetuses at 53-55 (n=6), 63-85 (n=6), 110 (n=4), 139-141 (n=4) and 144-145 (n=6) days gestation. Two animal models, known to alter pituitary function in the fetal sheep, were used to investigate corticotrophic adaptations to suboptimal uterine environments. For the maternal periconceptional undernutrition (PCUN) model, maternal feed was reduced to 70% of maintenance requirements from at least 45 days before to 7 days after mating and fetal tissues were collected at 53-55 days gestation (n=7). For the placental restriction (PR) model, the majority of the placental attachment sites were removed in five ewes before mating and fetal tissues were collected at 140 (n=4) and 144 (n=4) days gestation. Pituitary sections were simultaneously labelled with antisera raised against full length POMC, ACTH and CRHR₁ and the proportions of pituitary cells with combinations of antisera were quantified. Four subpopulations of corticotrophs were identified, which expressed either: POMC+ACTH+CRHR₁, ACTH+CRHR₁, POMC+ CRHR₁ or POMConly. There was a significant decrease in the proportion of pituitary cells expressing POMC+ACTH+CRHR₁ between 53-55 and 65-85 days gestation, before an increase at 110 days gestation and a further marked decrease between 139-141 and 144-145 days gestation. In fetuses from the PCUN group, the proportion of pituitary cells expressing POMC+ACTH+CRHR₁ in early gestation was reduced. PR resulted in a significantly higher proportion of corticotrophs expressing POMC+ACTH+CRHR₁ during the prepartum period. This work represents the discovery of the differential expression of POMC, ACTH and CRHR₁ in individual corticotrophs of the fetal sheep pituitary and the first insights into the pituitary adaptations to periconceptional nutrient restriction and placental restriction at the level of individual corticotrophs.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1337370
Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008
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Farrand, Kirsten. "Impact of environmental factors on the development of corticotroph subpopulations in the fetal sheep pituitary." Thesis, 2008. http://hdl.handle.net/2440/58643.
Full textAbstract:
The prepartum surge in fetal plasma cortisol, essential for the maturation of organs in mammals and the normal timing of parturition in some species, including sheep, may result from an increase in the molar ratio of adrenocorticotropin (ACTH) to pro-opiomelanocortin (POMC) in the fetal circulation. Related to this, the cleavage of POMC to ACTH by the enzyme, prohormone convertase 1 (PC1), may be influenced by corticotrophin releasing hormone (CRH) stimulation. Accumulating evidence suggests that the capacity of individual corticotrophs to process POMC to ACTH may vary and individual corticotrophs are differentially responsive to CRH. It is not known, however, if there are separate corticotroph subpopulations in the fetal sheep pituitary which can be identified by differential colocalisation of POMC, ACTH and the CRH receptor 1, CRHR₁, nor if changes in the relative proportions of such subpopulations play a role in the molecular mechanisms underlying the overall changes in pituitary function described previously during gestation and in response to suboptimal uterine environments. To investigate these hypotheses, it was first necessary to develop novel methods for the simultaneous immunohistochemical labelling of POMC, ACTH and CRHR₁ in individual cells on sections of fetal sheep pituitary. In addition, I developed and validated an automated method to categorise and count individual cells to increase the quantitative power of this study.
Pituitary tissue was collected from control fetuses at 53-55 (n=6), 63-85 (n=6), 110 (n=4), 139-141 (n=4) and 144-145 (n=6) days gestation. Two animal models, known to alter pituitary function in the fetal sheep, were used to investigate corticotrophic adaptations to suboptimal uterine environments. For the maternal periconceptional undernutrition (PCUN) model, maternal feed was reduced to 70% of maintenance requirements from at least 45 days before to 7 days after mating and fetal tissues were collected at 53-55 days gestation (n=7). For the placental restriction (PR) model, the majority of the placental attachment sites were removed in five ewes before mating and fetal tissues were collected at 140 (n=4) and 144 (n=4) days gestation. Pituitary sections were simultaneously labelled with antisera raised against full length POMC, ACTH and CRHR₁ and the proportions of pituitary cells with combinations of antisera were quantified. Four subpopulations of corticotrophs were identified, which expressed either: POMC+ACTH+CRHR₁, ACTH+CRHR₁, POMC+ CRHR₁ or POMConly. There was a significant decrease in the proportion of pituitary cells expressing POMC+ACTH+CRHR₁ between 53-55 and 65-85 days gestation, before an increase at 110 days gestation and a further marked decrease between 139-141 and 144-145 days gestation. In fetuses from the PCUN group, the proportion of pituitary cells expressing POMC+ACTH+CRHR₁ in early gestation was reduced. PR resulted in a significantly higher proportion of corticotrophs expressing POMC+ACTH+CRHR₁ during the prepartum period. This work represents the discovery of the differential expression of POMC, ACTH and CRHR₁ in individual corticotrophs of the fetal sheep pituitary and the first insights into the pituitary adaptations to periconceptional nutrient restriction and placental restriction at the level of individual corticotrophs.Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008
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Hagan, Ruth Patricia. "Cellular interactions in the development of autoimmunity in lambs and rats deprived of exposure to thyroid-specific antigens during development." Master's thesis, 1997. http://hdl.handle.net/1885/144279.
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Alsalami, Mohammed Taha Hadi. "The ontogeny of the haemopoietic system in foetal sheep." Phd thesis, 1985. http://hdl.handle.net/1885/143784.
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Rodrigues, Aline. "The Pathogenesis of Cache Valley Virus in the Ovine Fetus." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10584.
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Cache Valley virus (CVV) induced malformations have been previously reproduced in ovine fetuses; however, no studies have established the CVV infection sequence of the cells targeted by the virus or the development of the antiviral response of the early, infected fetus that results in viral clearance before development of immunocompetency. To address these questions, ovine fetuses at 35 dg were inoculated in utero with CVV and euthanized at 7, 10, 14, 21 and 28 dpi. On postmortem examination arthrogryposis and oligohydramnios were observed in some infected fetuses. Morphologic studies showed necrosis in the central nervous system (CNS) and skeletal muscle of earlier infected fetuses and hydrocephalus, micromyelia and muscular loss in later infected fetuses. Using immunohistochemistry and in situ hybridization, intense CVV viral antigenic signal was detected in the brain, spinal cord, skeletal muscles and fetal membranes of infected fetuses. Viral signal decreased in targeted and infected tissues with the progression of the infection.
To determine specific cell types targeted by CVV in the CNS, indirect immunofluorescence was applied to sections of the CNS using a double labeling technique with antibodies against CVV together with antibodies against neurons, astrocytes and microglia. CVV viral antigen was shown within the cytoplasm of neurons in the brain and spinal cord. No viral signal was observed in microglial cells; however, infected animals had marked microgliosis.
The antiviral immune response in immature fetuses infected with CVV was evaluated. Gene expression associated with an innate, immune response was quantified by real-time, quantitative PCR. Upregulated genes in infected fetuses included ISG15, Mx1, Mx2, IL-1, IL-6, TNF-?, TLR-7 and TLR-8. The amount of Mx protein, an interferon stimulated GTPase capable of restricting growth of bunyaviruses, was elevated in the allantoic and amniotic fluid in infected fetuses. ISG15 protein expression was significantly increased in target tissues of infected animals. B lymphocytes and immunoglobulin-positive cells were detected in lymphoid tissues and in the meninges of infected animals. This demonstrated that the infected ovine fetus is able to stimulate an innate and adaptive immune response before immunocompetency that presumably contributes to viral clearance in infected animals.
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Beck, Gerald Joseph. "The effect of antenatal palatal surgery on postnatal palatal growth in sheep a thesis submitted in partial fulfillment ... in oral and maxillofacial surgery ... /." 1986. http://catalog.hathitrust.org/api/volumes/oclc/68788161.html.
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Siphugu, Steven Mbonalo. "The efficiency of ultrasonorgraphy in monitoring ovarian structures and foetal development in goats, sheep and cattle as verified through laparoscopy and laparotomy." Diss., 2018. http://hdl.handle.net/11602/1148.
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MSCAGR (Animal Science)Department of Animal Science
The main purpose of this study was to assess the efficiency of ultrasonography in monitoring reproductive organs, pregnancy diagnosis, and foetal gender identification and to verify its reliability by laparoscopy and laparotomy, where applicable. Reproductive organs, pregnancy diagnosis and gender of the foetus were examined by A-mode ultrasound using 3.0 - 8.0 MHz trans-rectal transducer. A Sony Olympus Model laparoscope with a camera transducer was used to monitor the reproductive organs and pregnancy diagnosis. In monitoring the follicular dynamics, daily ultrasonography (ULTS) scanning was done for 17 days in sheep and for 21 days in both goats and cattle. Follicles of diameter ≥ 3 mm were selected for analysis of growth, ovulation and regression. For determining the efficiency of the techniques, laparoscopy (LAPSC) and laparotomy (LAPT) were used on days 3 and 10 of the goats and sheep oestrous cycle. The follicles were grouped into three categories according to their diameter as 3 - 4.9 mm, 5 - 7.9 mm and ≥ 8 mm, whereas the follicles of cattle were grouped as 3 - 4.9 mm, 5 - 9.9 mm and ≥ 10 mm. Early pregnancy diagnosis examinations were carried out from day 18 post insemination until pregnancy was confirmed. Foetal gender examinations were conducted from day 40 of pregnancy until the day the gender of the foetus was confirmed. Follicular development was accompanied by the occurrence of waves of follicular growth at different period of the oestrous cycle. The first follicular wave emerged on day 1.0 ± 0.4 in goats, 1.2 ± 0.4 in sheep and 2.2 ± 0.4 in cattle. The maximum diameter of the dominant follicles of observed follicular waves in goats was 7.3 ± 0.4 mm, 6.6 ± 0.2 mm, 7.3 ± 0.2 mm; in sheep was 6.4 ± 0.4 mm, 6.6 ± 0.4 mm and 6.7 ± 0.7 mm and in cattle was 13.1 ± 0.8 mm, 14.2 ± 0.6 mm and 15.7 ± 0.6 mm in wave 1, 2 and 3, respectively. However, the maximum size of the dominant follicle of the ovulatory wave in cattle was larger than the dominant follicles of both first and second waves, but in goats and sheep the dominant follicles were of similar size throughout the waves. In cattle, the ovulatory wave was shorter (p ˂ 0.05) than the duration of the first and second waves, while in sheep and goats were similar throughout the waves. In goats the total number of follicles counted in right and left ovaries under category 3 - 4.9 mm was lower with ULTS and LAPSC than with LAPT method (p ˂ 0.05). In sheep the mean number of follicles between 3 - 4.9 mm category in both right and left ovaries were different (p ˂ 0.05) between ULTS and LAPT. However, for categories 5 - 7.9 mm and ≥ 8 mm in both goats and sheep the mean numbers of follicles observed by all techniques were similar (p ˃ 0.05). In goats, pregnancy diagnosis accuracy improved from zero percent on day 18 to 100% on day 26 - 28, in sheep pregnancy diagnosis was 40% on day 18 and improved to 100% on day 20 - 22 vi of gestation. In cattle accuracy of pregnancy diagnosis was not possible at day 18 and gradually increased to 100% on day 30 - 32 of gestation. Out of 5 (100%) goat’s foetuses whose gender was determined, the diagnosis was correct in 100% (3/3) of the male foetuses and 100% (2/2) of the female foetuses. In sheep two foetuses were sexed as males while the other three were sexed as females and were both 100%. Out of 60% (3/5) of foetuses examined in cattle, 1 (100%) was identified as male and the remaining 2 (100%) were identified as females. The results obtained confirmed that the accuracy for foetal gender by ultrasonography was 100% in all foetuses observed. The current study demonstrated that trans-rectal ultrasonography examination is an efficient method for monitoring follicular dynamics, diagnosing pregnancy and foetal gender identification and that it is as reliable as laparoscopy and laparotomy where they were applied together.
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Sharma, Rajesh. "The effects of uterine environment upon embryonic, fetal, neonatal and post-natal development and glucose metabolism in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1689.
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Studies of humans and domestic animals have shown that there is a linkage between the neonatal and post-natal health of an individual and its uterine environment during gestation. However, very little information exists for sheep and there have been no studies that have directly examined the stage of gestation at which such effects could be introduced to the conceptus. In the present study, pure-breed embryos were transferred within and reciprocally between large (Suffolk: S) and small (Cheviot: C) breeds of sheep to establish different uterine environments; SinS (large control), SinC (restricted environment), CinS (luxurious environment) and CinC (small control) and their effects upon embryonic, fetal, neonatal and post-natal development and glucose metabolism of lambs were examined. By Day 19 of gestation, conceptuses (embryo and trophoblast) developing in a restricted uterine environment (SinC) were smaller (P<0.05) than in control (SinS). The head length of SinC fetuses was smaller (P<0.05) than in SinS fetuses on Day 55 of gestation and SinC lambs were lighter and smaller (P<0.05) than SinS lambs at birth. During subsequent post-natal life, there was no difference (P>0.05) in the growth rate of SinC and SinS lambs. The liveweight and body dimensions of SinC lambs were lower (P<0.05) than SinS lambs until 9 weeks and 12 weeks of age, respectively. Day 19 peri-implantation embryos and trophoblasts that developed in a luxurious environment were bigger than in control (CinC). However, CinS fetal size did not differ (P>0.05) from CinC fetuses by Day 55 of gestation. There was no difference (P>0.05) in the birthweight and body dimensions of lambs born from these two groups. Dimension of the placentas of SinC and SinS or CinS and CinC did not differ (P<0.05) during gestation or at lambing. Concentrations of ovine placental lactogen (oPL), progesterone, insulin-like growth factor-1 (IGF-1), glucose and free fatty acid (FFA) differed between uterine environments. During glucose challenge tests, there were no differences in the concentrations of glucose and insulin, between SinC and SinS female lambs, however, glucose concentrations declined more rapidly (P<0.05) in CinS than CinC female lambs at one year of age. It was concluded that restricted uterine environment affects embryonic, fetal and neonatal development of lambs, and that these effects perpetuates until at least one year of age; but there was no effect upon glucose metabolism. Conversely, a luxurious uterine environment enhances the early development of embryos but had no effects upon subsequent fetal, neonatal and post-natal development; however glucose metabolism of post-natal female lambs was improved. It appears that these effects of uterine environment were mediated through the trophoblast during the early embryonic period and via the placenta during subsequent gestation. oPL, progesterone, IGF-1, glucose and FFA were implicated in feto-maternal dialogue. These results suggest that uterine environment significantly influences the biology of young sheep with possible economic consequences.