Haematological Pathology

Permanent URI for this community

https://scholar.sun.ac.za/handle/10019.1/172

Browse

Browsing Haematological Pathology by browse.metadata.advisor "Abayomi, Akin"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Evaluation and validation of room temperature biospecimens transportation and storage technologies as an alternative cost effective solution to cold chain logistics and storage within biobanking and/or diagnostics
    (Stellenbosch : Stellenbosch University, 2017-03) Abulfathi, Fatima Adam; Swanepoel, Carmen Catherine-Ann; Grewal, Ravnit Kuar; Abayomi, Akin; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology: Haematological Pathology
    ENGLISH ABSTRACT : Background: Cold chain management (CCM) is an important aspect of biobanking operation. However challenges such as constant power failure, limited access to dry ice transport and storage of human samples collected at various sites all over the world or at difficult out of reach places. and liquid nitrogen, transport logistics and courier delays especially in Africa becomes a major challenge. Ensuring samples are maintained at the proper temperature throughout all processes is imperative to maximal long term viability and usability. Thus we consider room temperature storage (RTS) technologies as an innovative, cost effective and green alternative to cold chain logistics. Methods: Various room temperature storage technologies were evaluated for the stabilization and storage of whole blood DNA and RNA, buffy coat, genomic DNA and urine DNA. The stabilizers include the Biomatrica liquid gard technology and dry matrix technology as well as DNAgenotek Hemagene buffy-coat stabilizers, Paxgene RNA and Norgen urine tubes. Samples were stored with and without a stabilizer under different temperature conditions namely room temperature, 45oC,-80oC, -20oC and liquid nitrogen (- 196oC) over different time periods to determine effect on sample integrity and quality. At the end of each time point DNA/RNA was extracted and the integrity of the samples determined by assessing the concentration, purity and integrity. Further downstream analysis such as polymerase chain reaction (PCR), quantitative real time PCR and DNA sequencing was conducted. In addition, a shipping cost analysis between satellite sites in African and our biobank was done to compare frozen and room temperature shipping. Results The study results show that sample integrity/quality for biospecimens stored at room temperature with stabilizers were comparable and more cost effective than cold chain storage systems. In addition some stabilizers showed better stabilizing properties than others. Conclusion: Room temperature storage provides an innovative and cost effective method of storage and shipping to cold chain management systems (CCM). Green technologies forms a small part of biobanking operations however its results would be beneficial as low energy options for biobanking are particular critical in low resource settings which have infrastructural challenges. In turn, it would also be a more cost-effective option for the transport and storage of human samples collected at various sites all over the world or at difficult out of reach places.
  • Thumbnail Image
    Item
    Impact of inflammation-induced oxidative stress on the integrity of immuno-haematopoietic cells and potential ameliorating interventions in an in vitro HIV model
    (Stellenbosch : Stellenbosch University, 2013-12) Wanjiku, Samuel Mburu; Marnewick, Jeanine L.; Abayomi, Akin; Ipp, Hayley; Stellenbosch University. Faculty of Health Sciences. Dept. of Pathology. Haematological Pathology.
    ENGLISH ABSTRACT: Chronic inflammation and immune activation are hallmarks of HIV infection, resulting in chronic oxidative stress with over-utilization of antioxidant defences, which may contribute to the loss of immune cells and faster disease progression. Low levels of antioxidants in HIV- infected individuals have been associated with frequent opportunistic infections and an increased risk of mortality. HIV infection is also associated with on-going and aberrant activation of both the innate and adaptive immune systems. An important aspect of innate immune stimulation is derived from the leakage of lipopolysaccharide (LPS) across the damaged mucosal lining of the gut in early HIV infection. The impact of this innate immune stimulation on the adaptive arm of the immune system, as represented in this study by levels of CD4+ T-cell activation and death, have not been explored previously in untreated HIV infection. Using an integrated approach of immune activation, inflammation, oxidative stress and ameliorating antioxidant intervention for the first time, this thesis reports the impact of inflammatory induced-oxidative stress on CD4+ T-cells in an in vitro HIV model. In a preliminary study, baseline levels of neutrophil respiratory burst as an in vitro indication of immune stimulation were investigated. The relationships between baseline total antioxidant status (TAS), Red blood cell (RBC) antioxidant enzyme activities (catalase, superoxide dismutase & glutathione peroxidase), lipid peroxidation and glutathione redox ratio and other markers of disease in asymptomatic, untreated HIV infection were also explored. The design and optimization of an assay that could determine the effects of LPS-induced oxidative stress on CD4+ T-cells, was a critical part of this study. The development of this assay enabled the measurement of the effects of selected antioxidant interventions N-acetyl cysteine (NAC) and vitamin C, on LPS-induced CD4+ T-cell activation and death. The results were also correlated with CD4 count, viral load and markers of inflammation (fibrinogen & D-dimers) in HIV-infected and uninfected groups. Neutrophils from HIV-infected persons at rest showed a ―primed‖ response to low stimulating agent, bacterial N-formyl peptides (fMLP), which was significantly (P = 0.04) higher than uninfected individuals. There was increased oxidative stress as evidenced by increased catalase activity, malondialdehyde (MDA) and conjugated dienes (CDs) with a corresponding decrease in antioxidant capacity in HIV-infected individuals with lower CD4 count. NAC in combination with vitamin C, significantly (P = 0.0018) reduced activation of CD4+ T-cells to a greater degree than with either antioxidant alone. NAC and vitamin C individually and in combination significantly (P = 0.05, P = 0.012 and P<0.0001) decreased the expression of the markers of apoptosis, Annexin V and 7-amino-actinomycin (7-AAD). Importantly, the antioxidant combination decreased MDA values and significantly (P = 0.01) increased the glutathione redox ratio in the HIV-infected group. Based on these results, the respiratory burst and LPS-induced activation may be important contributing factors in inflammatory-associated oxidative stress in HIV infection and contribute to the depletion of CD4+ T-cells in the asymptomatic stage of HIV infection. These results also indicate the potential inhibitory effects of NAC and vitamin C in combination as agents that may limit immune activation and inflammation-induced oxidative stress. Importantly, the study showed that at this asymptomatic stage, CD4+ T-cells of the HIV-infected group responded similarly to stimulation as the HIV negative group, indicating that antioxidant defences were still functional and that appropriate early intervention at this stage may be protective against oxidative damage to the immune cells. To the best of our knowledge, this study is the first to use an integrated approach involving not only plasma levels of antioxidant status, but also RBC antioxidant enzyme activities, oxidative damage (lipid peroxidation), inflammation, cellular levels of immune activation and potential ameliorating interventions in evaluating the problem of inflammation-induced oxidative stress in HIV infection. Based on the results of this study, it is envisaged that an insight into the immune activation, inflammatory and oxidative stress status of patients will enable long-term profiling of each patient with a view to individualized therapy. This approach may have a direct impact on patient care in resource-limited settings such as sub-Saharan Africa.