VEGF and Sympathetic Perivascular Nerves Contribute to Hypoxic Remodeling of Ovine Cranial Arteries

Chronic hypoxia complicates many pregnancies and can result in postnatal pathologies that include compromised fetal cardiovascular structure and function. Mechanisms involved remain unclear. Because hypoxia increases production of VEGF, known to modulate smooth muscle (SM) phenotype, this thesis explored the hypothesis that VEGF contributes to hypoxic fetal vascular remodeling through direct effects on SM cells and indirectly through perivascular nerves. Using a chronic hypoxia sheep model, this work demonstrated that: 1) hypoxia potently upregulates VEGF receptor expression but not endogenous VEGF level in fetal ovine carotid arteries; 2) both chronic hypoxia and VEGF exert similar effects on smooth muscle contractile proteins; 3) both chronic hypoxia and VEGF exert similar effects on contractile protein colocalizations; and lastly, sympathetic autonomic nerves contribute to hypoxic reorganization of structure and function of vascular contractile proteins. Together, these findings advance understanding of how hypoxia precipitates fetal vascular remodeling and offer an essential first step toward finding new treatments for infants that survive in-utero hypoxia

Development of an Anaerobic Digester for Animal Waste

Advancement in biotechnology and bioengineering has provided ways that resources, which hitherto were classified as wastes, now form the basis for energy production. Anaerobic digestion is a highly promising technology used for processing biomass materials (crop residue, human excreta, animal waste and food) in the absence of oxygen to a methane-rich biogas. This work developed a small-scale anaerobic digester to produce biogas from animal waste. The anaerobic digester consisted of three major components: bioreactor with an incorporated stirrer driven by an electric motor, gas scrubber and gas collector.  Batch feeding operation was adopted while pig waste was used as test material. Lime water was used as a scrubbing medium for methane enrichment.  Loading result revealed that there was seven days delay in gas production from day of loading. The daily temperatures and pH recorded for a period of 50 days were in the range of 29 - 34°C and 5.5 - 7.5 respectively, and the average yield of clean biogas was 0.13 l/kg of slurry/day. Biogas generation increased with days in digester and was a two-stage process with a peak production day between 40 and 45 days.  There was observed reduction in carbon dioxide content and methane enrichment as the days increased confirming the effectiveness of the scrubber. The biogas produced comprised between 55.1 and 74.1% of methane, and a range of 22.5 to 38.2% of carbon dioxide and was combustible after the 10th day of digestion. The results obtained showed the overall functionability of the developed anaerobic digester. The digester could be deployed and adopted in farmsteads as well as household to meet their energy deman

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

Development of an Anaerobic Digester for Animal Waste

Advancement in biotechnology and bioengineering has provided ways that resources, which hitherto were classified as wastes, now form the basis for energy production. Anaerobic digestion is a highly promising technology used for processing biomass materials (crop residue, human excreta, animal waste and food) in the absence of oxygen to a methane-rich biogas. This work developed a small-scale anaerobic digester to produce biogas from animal waste. The anaerobic digester consisted of three major components: bioreactor with an incorporated stirrer driven by an electric motor, gas scrubber and gas collector. Batch feeding operation was adopted while pig waste was used as test material. Lime water was used as a scrubbing medium for methane enrichment. Loading result revealed that there was seven days delay in gas production from day of loading. The daily temperatures and pH recorded for a period of 50 days were in the range of 29 - 34°C and 5.5 - 7.5 respectively, and the average yield of clean biogas was 0.13 l/kg of slurry/day. Biogas generation increased with days in digester and was a two-stage process with a peak production day between 40 and 45 days. There was observed reduction in carbon dioxide content and methane enrichment as the days increased confirming the effectiveness of the scrubber. The biogas produced comprised between 55.1 and 74.1% of methane, and a range of 22.5 to 38.2% of carbon dioxide and was combustible after the 10th day of digestion. The results obtained showed the overall functionability of the developed anaerobic digester. The digester could be deployed and adopted in farmsteads as well as household to meet their energy deman

Dysregulation of Glucocorticoid Receptor Homeostasis and Glucocorticoid-Associated Genes in Umbilical Cord Endothelial Cells of Diet-Induced Obese Pregnant Sheep

Maternal obesity (MO) is associated with offspring cardiometabolic diseases that are hypothesized to be partly mediated by glucocorticoids. Therefore, we aimed to study fetal endothelial glucocorticoid sensitivity in an ovine model of MO. Rambouillet/Columbia ewes were fed either 100% (control) or 150% (MO) National Research Council recommendations from 60 d before mating until near-term (135 days gestation). Sheep umbilical vein and artery endothelial cells (ShUVECs and ShUAECs) were used to study glucocorticoid receptor (GR) expression and function in vitro. Dexamethasone dose–response studies of gene expression, activation of a glucocorticoid response element (GRE)-dependent luciferase reporter vector, and cytosolic/nuclear GR translocation were used to assess GR homeostasis. MO significantly increased basal GR protein levels in both ShUVECs and ShUAECs. Increased GR protein levels did not result in increased dexamethasone sensitivity in the regulation of key endothelial gene expression such as endothelial nitric oxide synthase, plasminogen activator inhibitor 1, vascular endothelial growth factor, or intercellular adhesion molecule 1. In ShUVECs, MO increased GRE-dependent transactivation and FKBP prolyl isomerase 5 (FKBP5) expression. ShUAECs showed generalized glucocorticoid resistance in both dietary groups. Finally, we found that ShUVECs were less sensitive to dexamethasone-induced activation of GR than human umbilical vein endothelial cells (HUVECs). These findings suggest that MO-mediated effects in the offspring endothelium could be further mediated by dysregulation of GR homeostasis in humans as compared with sheep