No description available.

No description available.

No description available.

Breast cancer is the second most common cancer in women in the United States, accounting for approximately 30% of newly diagnosed female cancers every year. In 2023, it is estimated that around 297,790 invasive breast cancers will be diagnosed as new cases with nearly 43,700 women deaths. The average lifetime risk of a woman in the United States accruing a breast cancer diagnosis is approximately 13%, meaning that there is a 1 in 8 chance of developing breast cancer. Classification of breast cancers is distinguished based on the presence of three receptors: HER2, estrogen, and progesterone. Absence of these receptors is categorized as triple negative breast cancer and accounts for about 15% of all breast cancers, thus is the most aggressive and difficult to treat. In this study, research involving two flavonoids, CT1 and CT3 show cytotoxic effects against cell lines MCF7 (ER+, PR+, HER2-) and SKBr3 (ER-, PR-, HER2+), that represent the most common breast cancers. CT1 and CT3 were extracted from the leaves of Chromolaena tacotana using a Soxhlet extractor, followed by isolation and purification by chromatography. The cells were seeded and then treated with CT1 or CT3 at concentrations of 5, 10, 20, 40 and 80 mM for cytotoxicity assays, and 40mM for analysis of mechanism of action via immunoblotting and TUNEL. These two flavonoids differ on the presence of a double bond between positions 2 and 3. At the concentrations tested, CT1 has cytotoxic activity against MCF7 but no significant effect on SKBr3, while CT3 has cytotoxic activity against SKBr3 but not on MCF7. CT1 and CT3 target the activated forms of ERK, c-JUN and SP6; however, the effect of CT1 appears to be significantly stronger than CT3 and does not involve the survival pathway. CT1 and CT3 inhibit cell viability in MCF7 and SKBr3 breast cancer cells by activating an extrinsic apoptotic pathway. Additional studies using a triple negative breast cancer cell line has shown that this activation is independent of the presence of estrogen and progesterone receptors or the upregulation of HER2.

No description available.

No description available.

This study had two objectives: to achieve suspension cultivation of Sf1Ep cells and to develop procedures for achieving the replication of T. pallidum in those cell cultures. Sf1Ep cells have been the sole cell line used for the in vitro cultivation of T. pallidum. A study was undertaken to determine if other cell lines can support growth of T. pallidum. Rabbit skin fibroblasts (RAB-9), nude mouse ear (NME) cells, and normal rebbit testis fibroblasts (RT) were compared to Sf1Ep cells for their ability to support in vitro multiplication of T. pallidum. RAB-9 cells supported multiplication of treponemes equal to that of Sf1Ep cells. NME and RT cells also supported growth but to a lesser extent than Sf1Ep cells. Utilization of alternative cell lines may lead to improved in vitro growth of T. pallidum including possible serial passage.

yes / Ibuprofen (IBF) is an outstanding non-steroidal drug for analgesic and anti-inflammatory therapies but it exhibits poor solubility in water [1, 2]. Increased dosage administration has been linked to gastrointestinal and cardiovascular complications [3]. Many techniques have been employed to improve the solubility of NSAIDs [4]. In this study, the anti-solvent precipitation method was used to make Ibuprofen nanoparticles (IBF NPs). Optimised preparation parameters such as solvent (ethanol), raw drug concentration (400 mg), solvent/anti-solvent ratio (1:50) and surfactant concentration (0.25 mg/ml) have been studied to yield nanoparticles with a mean size of 58.8 nm, which is confirmed by dynamic light scattering and transmission electron microscopy. These IBF NPs posess increased aqueous solubility compared to the micro counterpart and maintain with chemical integrity indicated by high performance liquid chromatography and Fourier transform infrared spectroscopy. In addition, in vitro cytotoxicity of IBF NPs has been studied on A549 and HaCat cell lines using MTT and LDH assays. Both cells were obtained from ATCC. The A549 cells were grown in a modification of Ham’s F-12, containing L-glutamine, called F-12K. The HaCaT cells were grown in DMEM containing sodium pyruvate (110 mg/l). Normal cell culture and sub-culture were applied and the cells were used after around 45 passages [5]. The cell culture media containing 105cells/ml were placed in a 96-well plate with addition of IBF NPs and Micro form at concentrations in the range of between 6 and 500 ug/ml by diluting them with DMEM and F-12K for use with the HaCaT and A549 cells respectively. After 24, 48 and 72h exposure, the MTT and LDH cytotoxicity assay were performed in triplicates and on three separate experiment cultures and the absorbance was recorded at 570 nm and 492nm respectively with Elisa micro plate reader. The cell viability (%) related to control (cells in culture medium without NPs) was calculated. A very good cytotoxicity profile was observed, indicating an in vitro cytocompatibility of the IBF NPs in these cell culture systems and no significant changes in cytotoxicity compared with Micro IBF. We conclude that our IBF NPs have increased solubility, same chemical integrity and unchanged cytotoxicity compared to IBF Micro drug. Further work will concentrate on optimising more rigorous parameter to produce excellent quality NPs. More detailed characterisation of IBF NPs is to be tested, such as using PXRD and SEM to further corroborate particle shape and size. The range of no toxic in vitro concentrations is also to be further confirmed. Eventually scaled up preparation of IBF NPs will be developed without relinquishing NPs quality. This would improve the potential for in vitro/ in vivo applications and clinical use of IBF NPs and NSAIDs in general.

Submitted in fulfilment of the requirements of the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2010. / Photodynamic therapy is a promising treatment for cancer. It involves the combination of a photosensitizer and light of an appropriate wavelength (laser source) to cause the destruction of cancer cells. Phthalocynanines are second–generation photosensitizers with enhanced photophysical and photochemical properties. In this in vitro study the effect of aluminium (AlTSPc) or zinc (ZnTSPc) tetrasulfophthalocyanines in its inactive and active state (laser induced) on melanoma (skin cancer cells), fibroblast (healthy normal skin cells) and keratinocyte (healthy normal skin cells) cells was evaluated. For each of the cell lines approximately 3 x 104 cells/ml were seeded onto 24-well cell culture plates and allowed to attach overnight, after which cells were treated with different concentrations of AlTSPc or ZnTSPc. The photosensitizers were synthesized at Rhodes University. After 2 hrs, cells were irradiated with a diode laser at a wavelength of 672 nm and a beam diameter of 1 cm. The laser power varied between 20-30 mW and the irradiation time was calculated to deliver a light dose of 4.5 J/cm2. Post-irradiated cells were incubated for 24 hrs before cell viability was measured using the CellTiter-BlueTM Viability Assay. Also, the efficacy of the light dose and laser source used for the killing of approximately 50% of the melanoma cancer cells were investigated. AlTSPc and ZnTSPc decreased cell viability of melanoma cancer cells to approximately 50% with photosensitizer concentrations of 40 μg/ml and 50 μg/ml respectively. These photosensitizer concentrations caused a slight decrease in the percentage cell viability of fibroblast and keratinocyte cells. Results for the dark toxicity assay showed that iii both photosensitizers in the presence of high concentrations (60 μg/ml – 100 μg/ml) showed cytotoxicity effects on melanoma cancer cells in their inactive state. This was not observed in fibroblast and keratinocyte cells treated under the same experimental conditions. The optimal AlTSPc and ZnTSPc concentrations in combination with the light dose of 4.5 J/cm2 was the most efficient in killing the melanoma cancer cells with reduced killing effects on healthy normal fibroblast and keratinocyte cells when compared to other light doses (2.5 J/cm2, 7.5 J/cm2 and 10 J/cm2). The irradiation of cells photosensitized with the optimal photosensitizer concentrations with a femtosecond laser using similar laser parameters to continuous wave laser experiments resulted in a reduction in the cell viability of healthy normal fibroblast and keratinocyte cells compared to melanoma cancer cells. The presence of DNA degradation on agarose gel, morphological changes like blebbing and ultrastructural changes like nucleus condensation indicated that photodynamic therapy treated melanoma cancer cells with the optimal concentrations of AlTSPc and ZnTSPc induced cell death via apoptosis. This concludes that low concentrations of AlTSPc and ZnTSPc activated with an appropriate laser source can be used to induce cell death in melanoma cancer cells. Both AlTSPc and ZnTSPc exhibit the potential to be used as a photosensitizer in photodynamic therapy for the treatment of melanoma cancer with the occurrence of minimal damage to surrounding healthy tissue.

published_or_final_version / Anatomy / Master / Master of Philosophy