Thesis (M. Tech. (Clinical Technology)) -- Central University of technology, Free State, 2012 / Introduction: Reference ranges for cardiac measurement are available for adults, children and term infants but the same cannot be said for preterm or small for gestational age (SGA) infants surviving as a result of modern intensive care units. No published data of reference ranges for preterm infants exists for the South African population. Infants with congenital heart disease are twice as likely to be small for their gestational age and these reference ranges may affect clinical management decisions, therapeutic response and prognosis of these neonates. The aim was thus to establish reference ranges for cardiac dimensions and functional values for preterm and low birth weight infants for central South Africa and compare them with international standards. Methods: A total of 290 infants of less than 34 weeks of age and weighing less than 2500g at birth were examined during a twelve month period by echocardiography during the first 0-28 days of life. The study assessed normative cardiac measurements divided in M-Mode, 2-D and functional measurement for these infants in 3 weight groups. Exclusion criteria were applied to any condition affecting the size and functionality of the cardiac system. The following dimensions were measured: Standard M-Mode values for the left ventricle, 2D measurements of valve mitral and tricuspid orifices, as well as functional assessments including Shortening fraction (SF %), Ejection fraction (EF %), and Muscle performance Index (MPI)-index of the Left and Right ventricle. Measurements were done by the leading edge methodology following the ASE recommendations. A longitudinal study was also done to examine changes in these indices over the first month- on day 14 and day 28 of life. Interobserver differences were calculated for the variability between measurements of a single scan- 25 babies were re-measured and produced good repeatability. Results: 290 infants were included to produce Referance ranges of measurements (means and standard deviations) for 3 weight groups namely: <0.999g, 1000-1499g, and 1500g – 2500g. The gestational age’s ranges between 26-38 weeks with a median of 31 weeks, gender distribution was almost equal with a slight female preponderance. Body surface area ranged from a minimum from 0.076 m² and a maximum of 0.184 m², the body weight ranged between a minimum of 690g and a maximum of 2500g with a median of 1360g. Discussion: The left ventricular diastolic and systolic, interventricular septum, posterior wall, aortic and left atrium dimensions showed a proportionate increase in diameter with an increase in body weight There were no differences in cardiac dimensions between Small for Gestational age” (SGA) versus “Average for Gestational age” (AGA). Gender and race played no role in any functional measurements or with the cardiac sizes. Weight correlated well with BSA and the data suggest that weight only can be used to develop tables for clinical use. Cardiac chambers increased with BSA and weight and functional measurements stayed the same throughout the weight groups. Systolic and global functions were remarkably similar and constant throughout weight categories. . The longitudinal study also confirmed that the values are applicable to all low birth weight infants up to 28 days of age. Differences existed between some of the average South African infant’s cardiac chambers and international values. The Inter Ventricular Septum (IVS) and Posterior Wall (PW) measured thicker and the Left Atrium larger. This could be due to numerous factors that should be investigated further. Conclusion: The study emphasized the profound effect of growth and weight gain on the cardiac structure and that population specific reference values should therefore be developed and used.

The incidence of Low Birth Weight (LBW) babies born in the Uitenhage Provincial Hospital would seem to be a cause of concern from a public health of view. The incidence of 21% recorded during 1999 is markedly higher than the 7% recorded in the United States of America in 1998 and the average of 17% noted for developing countries. Some health concerns related to LBW babies are Sudden Infant Death Syndrome, scholastic performances later in life, and several chronic diseases in adults associated with them having been born as LBW babies.

Thesis (MA. (Clinical Psychology)) -- University of Limpopo, 2004. / Refer to the document

The incidence of Low Birth Weight (LBW) babies born in the Uitenhage Provincial Hospital would seem to be a cause of concern from a public health of view. The incidence of 21% recorded during 1999 is markedly higher than the 7% recorded in the United States of America in 1998 and the average of 17% noted for developing countries. Some health concerns related to LBW babies are Sudden Infant Death Syndrome, scholastic performances later in life, and several chronic diseases in adults associated with them having been born as LBW babies.

A world-wide series of epidemiological studies has demonstrated that there is an association between being born small and the risk of visceral obesity, a more central deposition of subcutaneous fat and insulin resistance in adult life. In the lamb, intrauterine growth restriction (IUGR) results in a low birth weight and an increased visceral fat mass by 45d of postnatal life. In this thesis I have investigated the effect of IUGR on adipose tissue development and function during fetal and early postnatal life in the sheep. IUGR was induced by removal of the majority of endometrial caruncles in non pregnant ewes prior to mating which resulted in the subsequent placental restriction of fetal growth (PR). Fetal blood samples were collected from 116d gestation and visceral perirenal adipose tissue (PAT) collected from PR and control fetuses at 145d. In lambs IUGR was defined as a birth weight less than 2 standard deviations below the mean of a cohort of singleton Merino lambs. Blood samples were collected throughout the first 3 weeks of life and PAT and subcutaneous adipose tissue (SAT) was collected at 21 d. It was determined whether IUGR alters the expression of genes which regulate adipogenesis (IGF1, IGFR1, IGF2, IGFR2, PPARy, and RXRα), adipocyte metabolism (LPL, G3PDH, GAPDH) and adipokine signalling (leptin, adiponectin) in adipose tissue depots before and after birth using qRT-PCR. PR fetuses were hypoglycaemic, hypoinsulinaemic, hypoxic, and had a lower body weight than Control fetuses. The expression of both IGF1 and leptin mRNA in PAT, the major fetal adipose depot, was lower in the PR fetuses, although there was no difference in the expression of other adipokine or adipogenic genes in PAT between PR and control fetuses. Thus restriction of placental and hence fetal substrate supply results in decreased IGF1 and leptin expression in fetal visceral adipose tissue which may alter the functional development of the perirenal fat depot and contribute to altered leptin signalling in the growth restricted newborn and the subsequent emergence of an increased visceral adiposity. At 21d of postnatal life there was no increase in the relative mass of perirenal or subcutaneous fat in IUGR lambs compared with controls. Thus, this study has investigated the effect of IUGR on the development of adipose tissue prior to the development of an obese phenotype. At 21d of life there was a sex specific effect of IUGR on the expression of PPARy and leptin mRNA in perirenal visceral fat such that PPARy and leptin mRNA expression was decreased in male IUGR lambs, but not females. Interestingly PAT mass was greater in females than males, independent of birth weight. Plasma insulin concentrations during the first 24h after birth predicted the size of the adipocytes and expression of adiponectin in visceral adipose tissue in both males and females at 21d. Thus, the nutritional environment before, and immediately after birth, may program adipocyte growth and gene expression in visceral adipose tissue. The differential effect of sex and birth weight on PPARy and leptin expression in visceral fat may be important in the subsequent development of visceral obesity and the insulin resistant phenotype in later life. At 21d of life there was no difference between Control and IUGR lambs in the relative mass of subcutaneous fat, or the expression of PPARy, RXRα, leptin, adiponectin, LPL, G3PDH, and GAPDH in subcutaneous fat at 21d of life. We have shown that the growth of the subcutaneous fat depot is related to plasma glucose, insulin and leptin concentrations, and to the development of perirenal fat. Thus, in contrast to perirenal adipose tissue, the postnatal, but not the fetal nutritional environment, programs subcutaneous adipocyte growth and gene expression. This thesis speculates that there may be a factor secreted from visceral fat that influences the development of the subcutaneous fat depot. At 21d of life there was also an effect of sex, but not IUGR, on the expression of IGF mRNA in adipose tissue. Male lambs had a higher expression of IGF1 mRNA in both PAT and SAT, and a higher expression of IGF1R and IGF2R in SAT compared with female lambs. It is likely that these differences in IGF mRNA levels reflect sexual dimorphism of the GH-IGF axis. When male and female lambs were combined there was a higher expression of IGF1 mRNA in SAT compared with PAT, and a higher expression of IGF2, IGF1R and IGF2R mRNA in PAT compared with SAT. These differences in IGF mRNA expression provide a potential mechanism to explain the sex and depot specific variations in mitogenic potency of IGF1 and proliferative capacities of preadipocytes, the regional variation in adipocyte metabolism, and the difference in incidence of visceral obesity between men and women in adult life. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347421 / Thesis (Ph.D.) - University of Adelaide, School of Molecular and Biomedical Science, 2008

A world-wide series of epidemiological studies has demonstrated that there is an association between being born small and the risk of visceral obesity, a more central deposition of subcutaneous fat and insulin resistance in adult life. In the lamb, intrauterine growth restriction (IUGR) results in a low birth weight and an increased visceral fat mass by 45d of postnatal life. In this thesis I have investigated the effect of IUGR on adipose tissue development and function during fetal and early postnatal life in the sheep. IUGR was induced by removal of the majority of endometrial caruncles in non pregnant ewes prior to mating which resulted in the subsequent placental restriction of fetal growth (PR). Fetal blood samples were collected from 116d gestation and visceral perirenal adipose tissue (PAT) collected from PR and control fetuses at 145d. In lambs IUGR was defined as a birth weight less than 2 standard deviations below the mean of a cohort of singleton Merino lambs. Blood samples were collected throughout the first 3 weeks of life and PAT and subcutaneous adipose tissue (SAT) was collected at 21 d. It was determined whether IUGR alters the expression of genes which regulate adipogenesis (IGF1, IGFR1, IGF2, IGFR2, PPARy, and RXRα), adipocyte metabolism (LPL, G3PDH, GAPDH) and adipokine signalling (leptin, adiponectin) in adipose tissue depots before and after birth using qRT-PCR. PR fetuses were hypoglycaemic, hypoinsulinaemic, hypoxic, and had a lower body weight than Control fetuses. The expression of both IGF1 and leptin mRNA in PAT, the major fetal adipose depot, was lower in the PR fetuses, although there was no difference in the expression of other adipokine or adipogenic genes in PAT between PR and control fetuses. Thus restriction of placental and hence fetal substrate supply results in decreased IGF1 and leptin expression in fetal visceral adipose tissue which may alter the functional development of the perirenal fat depot and contribute to altered leptin signalling in the growth restricted newborn and the subsequent emergence of an increased visceral adiposity. At 21d of postnatal life there was no increase in the relative mass of perirenal or subcutaneous fat in IUGR lambs compared with controls. Thus, this study has investigated the effect of IUGR on the development of adipose tissue prior to the development of an obese phenotype. At 21d of life there was a sex specific effect of IUGR on the expression of PPARy and leptin mRNA in perirenal visceral fat such that PPARy and leptin mRNA expression was decreased in male IUGR lambs, but not females. Interestingly PAT mass was greater in females than males, independent of birth weight. Plasma insulin concentrations during the first 24h after birth predicted the size of the adipocytes and expression of adiponectin in visceral adipose tissue in both males and females at 21d. Thus, the nutritional environment before, and immediately after birth, may program adipocyte growth and gene expression in visceral adipose tissue. The differential effect of sex and birth weight on PPARy and leptin expression in visceral fat may be important in the subsequent development of visceral obesity and the insulin resistant phenotype in later life. At 21d of life there was no difference between Control and IUGR lambs in the relative mass of subcutaneous fat, or the expression of PPARy, RXRα, leptin, adiponectin, LPL, G3PDH, and GAPDH in subcutaneous fat at 21d of life. We have shown that the growth of the subcutaneous fat depot is related to plasma glucose, insulin and leptin concentrations, and to the development of perirenal fat. Thus, in contrast to perirenal adipose tissue, the postnatal, but not the fetal nutritional environment, programs subcutaneous adipocyte growth and gene expression. This thesis speculates that there may be a factor secreted from visceral fat that influences the development of the subcutaneous fat depot. At 21d of life there was also an effect of sex, but not IUGR, on the expression of IGF mRNA in adipose tissue. Male lambs had a higher expression of IGF1 mRNA in both PAT and SAT, and a higher expression of IGF1R and IGF2R in SAT compared with female lambs. It is likely that these differences in IGF mRNA levels reflect sexual dimorphism of the GH-IGF axis. When male and female lambs were combined there was a higher expression of IGF1 mRNA in SAT compared with PAT, and a higher expression of IGF2, IGF1R and IGF2R mRNA in PAT compared with SAT. These differences in IGF mRNA expression provide a potential mechanism to explain the sex and depot specific variations in mitogenic potency of IGF1 and proliferative capacities of preadipocytes, the regional variation in adipocyte metabolism, and the difference in incidence of visceral obesity between men and women in adult life. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347421 / Thesis (Ph.D.) - University of Adelaide, School of Molecular and Biomedical Science, 2008

Thesis (Ph.D.)--Pardee Rand Graduate School, 2007. / Title from title screen (viewed on June 13, 2008). Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1989.

Thesis (M.Sc.)--Memorial University of Newfoundland, Faculty of Medicine, 1999. / Typescript. Bibliography: leaves 204-215.

Thesis (M.S.)--University of Michigan, 1989.