http://hdl.handle.net/123456789/870 2026-04-09T23:48:58Z http://hdl.handle.net/123456789/985 Developing Biomimetic Hydrogels of the Arterial Wall as a Prothrombotic Substrate for in Vitro Human Thrombosis Models Jacob Ranjbar; Wanjiku Njoroge; Paul Roach; Ying Yang; Jonathan M. Gibbins; Alan G. S. Harper Current in vitro thrombosis models utilise simplistic 2D surfaces coated with purified components of the subendothelial matrix. The lack of a realistic humanised model has led to greater study of thrombus formation in in vivo tests in animals. Here we aimed to develop 3D hydrogel-based replicas of the medial and adventitial layers of the human artery to produce a surface that can optimally support thrombus formation under physiological flow conditions. These tissueengineered medial- (TEML) and adventitial-layer (TEAL) hydrogels were developed by culturing human coronary artery smooth muscle cells and human aortic adventitial fibroblasts within collagen hydrogels, both individually and in co-culture. Platelet aggregation upon these hydrogels was studied using a custom-made parallel flow chamber. When cultured in the presence of ascorbic acid, the medial-layer hydrogels were able to produce sufficient neo-collagen to support effective platelet aggregation under arterial flow conditions. Both TEML and TEAL hydrogels possessed measurable tissue factor activity and could trigger coagulation of platelet-poor plasma in a factor VII-dependent manner. Biomimetic hydrogel replicas of the subendothelial layers of the human artery are effective substrates for a humanised in vitro thrombosis model that could reduce animal experimentation by replacing current in vivo models 2023-06-01T00:00:00Z http://hdl.handle.net/123456789/984 HIV-1 Transmission Cluster in Injection Drug Users in Nairobi City, Kenya Sella K; Mark Kilongosi; Godwil Munyekenye; David Onyango; Immaculate Marwa; Nancy Bowen While there is a striking increase in the prevalence of HIV in injection drug users, information on envelope-gene subtypes and transmission clusters in injection drug users is scarce. METHOD: In a cross-sectional study, 247 injection drug users were recruited via out-rich method. Deoxyribonucleic acid was extracted from dry blood spot samples, amplified by Polymerase Chain Reaction and sequenced. Subtyping was performed using COntext-based Modeling for Expeditious Typing (COMET) and Recombinant Identification Program (RIP) tools. Phylogenetic diversity and Transmission clusters were identified using MEGA version 6.0 and TreeLink, respectively. RESULTS: Overall, 42 (17.0%) injection drug users were sero-positive for HIV-1. Of the 37 samples successfully sequenced, 29 (78.4%) sequences were identified as A1, 6 (16.2%) as AG while 1 (2.7%) as A1/G/AE and A1/C recombinants. The HIV subtypes formed clusters with little genetic diversity. The high HIV prevalence was associated with transmission clusters and diversity in subtypes indicating ongoing local transmission. Therefore, there is need for comprehensive HIV care tailored to this population 2023-03-01T00:00:00Z http://hdl.handle.net/123456789/983 Utilization of Partograph in the Management of Women in Labor among Nurses Working in Embu County, Kenya Boraya JO; Annastacia Mbisi; Githae CN A partograph is a graphical representation of the fetal status, maternal status and progress of labor. Its proper interpretation assists in early identification of complications which may lead to morbidity and mortality. The study was to determine the utilization of the partograph in management of women in labor in Embu County. The objectives of the study were to determine the level of utilization of the partograph, and nurses related factors influencing the utilization of the partograph. A cross-sectional study design was conducted in selected hospitals within Embu County. The study population comprised of 124 nurses working in maternity wards. Purposive sampling technique was used to choose health facilities under study while simple random sampling of participants was done. Structured questionnaires were used to collect quantitative data while focused group discussions were conducted and key informants interviewed for qualitative data. Data collected and analyzed using SPSS Version 23 and presented by use of tables, figures, bar charts and narration. Binary logistic regression was used to assess the possible association and strength of association was measured using 95% confidence interval, chi-square was used to check for statistically significant results at a p value of 0.05. The study revealed that, nurses related factors influencing utilization of the partograph included negative attitude and lack of training on partograph use. Majority of nurses working in labor ward felt that partograph use is time consuming and needed supervision on partograph use. In addition, majority of the nurses were not trained on Partograph use from the time they graduated from college. The study recommends policy makers and nursing administrators to ensure that all qualified nurses use the partograph in the care of women in labor. 2021-06-01T00:00:00Z http://hdl.handle.net/123456789/888 Detection of lipid efflux from foam cell models using a label-free infrared method. Analyst, 147(23), 5372-5385. Xie, B., Njoroge, W., Dowling, L. M., Sulé-Suso, J., Cinque, G., Yang, Y. . Cardiovascular diseases are still among the leading causes of mortality and morbidity worldwide. The build-up of fatty plaques in the arteries, leading to atherosclerosis, is the most common cause of cardiovascular diseases. The central player in atherosclerotic plaque formation is the foam cell. Foam cells are formed when monocytes infiltrate from the blood stream into the sub-endothelial space, differentiating into macrophages. With the subsequent uptake and storage of lipoprotein, especially low-density lipoprotein (LDL), they change their phenotype to lipid laden cells. Lowering circulating LDL levels, or initiating cholesterol efflux/reverse cholesterol transport in foam cells, is one of the current clinical therapies. Prescription of the pleiotropic drugs, statins, is the most successful therapy for the treatment and prevention of atherosclerosis. In this study, we used a foam cell model from the macrophage cell line, RAW 246.7, and applied the label-free Fourier Transform Infrared Spectroscopy (FTIR) method, i.e. synchrotron-based microFTIR spectroscopy, to study the lipid efflux process initiated by statins in a dose and time dependent manner. We used glass coverslips as substrates for IR analysis. The optical images (visible and fluorescent light) clearly identify the localization and lipid distribution within the foam cells, and the associated changes before and after culturing them with atorvastatin at concentrations of 0.6, 6 and 60 μg mL−1, for a culture duration between 24 to 72 hours. MicroFTIR spectroscopic spectra uniquely displayed the reduction of lipid content, with higher lipid efflux observed at higher doses of, and longer incubation time with, atorvastatin. Principal Component Analysis (PCA) and t-distributed Stochastic Neighbor Embedding (t-SNE) analysis demonstrated defined cluster separation at both lipid (3000–2800 cm−1) and fingerprint (1800–1350 cm−1) regions, with more profound discrimination for the atorvastatin dose treatment than time treatment. The data indicate that combining synchrotron-based microFTIR spectroscopy and using glass substrates for foam cells can offer an alternative tool in atherosclerosis investigation at a molecular level, and through cell morphology. 2022-10-01T00:00:00Z