Showing items 1 - 20 of 56

A review of the photodynamic application of 5-aminolevulinic acid, hypericin and phthalocyanines in dermatology

- Ndhundhuma, I.M., Abrahamse, Heidi

  • Authors: Ndhundhuma, I.M. , Abrahamse, Heidi
  • Date: 2016
  • Subjects: Skin cancer , Photodynamic therapy and diagnosis , Fluorescence
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/215251 , uj:21383 , Citation: Ndhundhuma, I.M & Abrahamse, H. 2016. A review of the photodynamic application of 5-aminolevulinic acid, hypericin and phthalocyanines in dermatology.
  • Description: Abstract: Ultraviolet radiation can damage human skin leading to photo-aging and cancer. Treatment options for skin cancers are available. Amongst them, there is photodynamic therapy (PDT), the treatment modality that involves a photochemical reaction between a light sensitive compound, visible light and tissue oxygen. In PDT, a photosensitive compound also called photosensitizer (PS) is administered and allowed to accumulate in the cancerous tissue then irradiated with light corresponding to absorption wavelength of the PS, in the presence of molecular oxygen, to produce cytotoxic species that kill the cancerous tissue. PDT is increasingly used and studied globally for the treatment of different classes of cancers because of its selective destruction of diseased tissue or cancer. Newly developed non-invasive imaging technologies including photodynamic diagnosis, may assist with early identification of skin cancer to reduce the rates of morbidity and mortality following treatment. Photodynamic diagnosis (PDD) is a diagnostic modality defined from the PDT principle. It utilizes light and fluorescent PS to highlight tumour cells from normal cells. Excitation of PS by appropriate light source causes them to fluoresce over well-defined spectral regions. Therefore, the fluorescent properties of PSs can serve as an important diagnostic tool to highlight cancer at an early stage of development. In this review, our knowledge about PDT and PDD of skin cancers using 5-aminolevulinic acid (ALA), Hypericin and phthalocyanines as photosensitizers is presented.
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Advancement of nanobiomaterials to deliver natural compounds for tissue engineering applications

- Dhilip Kumar, Sathish Sundar, Abrahamse, Heidi

Anti-Proliferative, Analgesic and Anti-Inflammatory Properties of Syzygium mundagam Bark Methanol Extract

- Chandran, Rahul, George, Blassan P., Abrahamse, Heidi

  • Authors: Chandran, Rahul , George, Blassan P. , Abrahamse, Heidi
  • Date: 2020
  • Subjects: Lactate dehydrogenase , Hoechst stain , Granuloma tissue
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/425298 , uj:36406 , Rahul, C., George, B.P., Abrahamse, H.: Anti-Proliferative, Analgesic and Anti-Inflammatory Properties of Syzygium mundagam Bark Methanol Extract. DOI: 10.3390/molecules25122900
  • Description: Abstract: Cancer, pain and inflammation have long been a cause for concern amongst patients, clinicians and research scientists. There is an alarming increase in the demand for medicines suppressing these disease conditions. The present study investigates the role of Syzygium mundagam bark methanol (SMBM) extract against MCF-7 breast cancer cells, pain and inflammation. The MCF-7 cells treated with SMBM were analyzed for adenosine triphosphate (ATP), lactate dehydrogenase (LDH) levels, changes in cell morphology and nuclear damage. Hot plate, acetic acid and formalin-induced pain models were followed to determine the analgesic activity. Anti-inflammatory activity was studied using carrageenan, egg albumin and cotton pellet induced rat models. Microscopic images of cells in SMBM treated groups showed prominent cell shrinkage and nuclear damage. Hoechst stain results supported the cell death morphology. The decline in ATP (47.96%) and increased LDH (40.96%) content indicated SMBM induced toxicity in MCF-7 cells. In the in vivo study, a higher dose (200 mg/kg) of the extract was found to be effective in reducing pain and inflammation. The results are promising and the action of the extract on MCF-7 cells, pain and inflammation models indicate the potential of drugs of natural origin to improve current therapies.
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Apoptotic efficacy of multifaceted biosynthesized silver nanoparticles on human adenocarcinoma cells

- George, Blassan Plackal Adimuriyil, Kumar, Neeraj, Abrahamse, Heidi, Ray, Suprakas Sinha

  • Authors: George, Blassan Plackal Adimuriyil , Kumar, Neeraj , Abrahamse, Heidi , Ray, Suprakas Sinha
  • Date: 2018
  • Language: English
  • Type: Article
  • Identifier: http://ujcontent.uj.ac.za8080/10210/387555 , http://hdl.handle.net/10210/280207 , uj:30105 , Citation: George, B.P.A., Kumar, N., Abrahamse, H. & Ray, S.S. 2018. Apoptotic efficacy of multifaceted biosynthesized silver nanoparticles on human adenocarcinoma cells.
  • Description: Abstract: Metallic nanoparticles (NPs) especially silver (Ag) NPs have shown immense potential in medical applications due to their distinctive physio-chemical and biological properties. This article reports the conjugation of Ag NPs with Rubus fairholmianus extract. The modification of Ag NPs was confirmed using various physico-chemical characterization techniques. The cytotoxic effect of Rubus-conjugated Ag NPs (RAgNPs) was studied by LDH assay and proliferation by ATP assay. The apoptotic inducing ability of the NPs were investigated by Annexin V/PI staining, caspase 3/7 analysis, cytochrome c release, intracellular ROS analysis, Hoechst staining and mitochondrial membrane potential analysis using flow cytometry. The expression of apoptotic proteins caspase 3, Bax and P53 were analyzed using ELISA and caspase 3, Bax using western blotting. Cells treated with 10 µg/mL RAgNPs showed an increased number of cell death by microscopic analysis compared to untreated control cells. The RAgNPs induced a statistically significant dose-dependent decrease in proliferation (p < 0.001 for 5 and 10 µg/mL) and increased cytotoxicity in MCF-7 cells. A 1.83 fold increase in cytotoxicity was observed in cells treated with 10 µg/mL (p < 0.05) compared to the untreated cells. Nuclear damage and intracellular ROS production were observed upon treatment with all tested concentrations of RAgNPs and the highest concentrations (5 and 10 µg/mL) showed significant (p < 0.05, p < 0.01) expression of caspase 3, Bax and P53 proteins. The data strongly suggest that RAgNPs induces cell death in MCF-7 cells through the mitochondrial-mediated intrinsic apoptosis pathway. The present investigation supports the potential of RAgNPs in anticancer drug development.
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Biochemical responses of isolated lung CSCs after application of low intensity laser irradiation

- Abrahamse, Heidi, Crous, Anine

  • Authors: Abrahamse, Heidi , Crous, Anine
  • Date: 2016
  • Subjects: High fluence low intensity laser irradiation , Lung cancer stem cells
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/215358 , uj:21404 , Citation: Abrahamse, H & Crous, A. 2016. Biochemical responses of isolated lung CSCs after application of low intensity laser irradiation.
  • Description: Abstract: Studies have shown that using high fluences of Low Intensity Laser Irradiation (HF-LILI) produce apoptotic effects on normal and neoplastic cells. This study aimed to determine whether HF-LILI induce cell death in lung CSCs. Lung CSCs were isolated using the stem cell marker CD 133, characterized using flow cytometry, and applied in experiments which included treatment with LILI at wavelengths of 636, 825 and 1060 nm with fluences ranging from 5 J/cm2 to 40 J/cm2. Viability and proliferation studies, using Alamar blue assay and adenosine triphosphate luminescence (ATP), indicated an increase when treating lung CSCs with low fluences of 5 - 20 J/cm2 and a decrease in viability and proliferation as well as an increase in apoptosis when applying a fluence of 40 J/cm2 indicated by flow cytometry using Annexin V and propidium iodide (PI) dyes. Results indicate that LILI, when treating lung CSCs, can induce either a bio-stimulatory or bio-inhibitory effect depending on the wavelength and fluence used. This study indicated successful apoptotic induction of lung CSCs. Future experiments should be able to conclude the exact mechanism behind HF-LILI, which can be used in the targeted treatments of CSC elimination, implementing HF-LILI in the same manner as PDT in the absence of a photosensitizer.
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Cell adhesion molecules are mediated by photobiomodulation at 660 nm in diabetic wounded fibroblast cells

- Houreld, Nicolette N., Ayuk, Sandra M., Abrahamse, Heidi

  • Authors: Houreld, Nicolette N. , Ayuk, Sandra M. , Abrahamse, Heidi
  • Date: 2018
  • Subjects: Diabetes , Extracellular matrix , Fibroblasts
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/268765 , uj:28535 , Citation: Houreld, N.N., Ayuk, S.M. & Abrahamse, H. 2018. Cell adhesion molecules are mediated by photobiomodulation at 660 nm in diabetic wounded fibroblast cells. Cells 2018, 7:1-17. doi:10.3390/cells7040030
  • Description: Abstract: Diabetes affects extracellular matrix (ECM) metabolism, contributing to delayed wound healing and lower limb amputation. Application of light (photobiomodulation, PBM) has been shown to improve wound healing. This study aimed to evaluate the influence of PBM on cell adhesion molecules (CAMs) in diabetic wound healing. Isolated human skin fibroblasts were grouped into a diabetic wounded model. A diode laser at 660 nm with a fluence of 5 J/cm2 was used for irradiation and cells were analysed 48 h post-irradiation. Controls consisted of sham-irradiated (0 J/cm2) cells. Real-time reverse transcription (RT) quantitative polymerase chain reaction (qPCR) was used to determine the expression of CAM-related genes. Ten genes were up-regulated in diabetic wounded cells, while 25 genes were down-regulated. Genes were related to transmembrane molecules, cell–cell adhesion, and cell–matrix adhesion, and also included genes related to other CAM molecules. PBM at 660 nm modulated gene expression of various CAMs contributing to the increased healing seen in clinical practice. There is a need for new therapies to improve diabetic wound healing. The application of PBM alongside other clinical therapies may be very beneficial in treatment.
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Cell death pathways and phthalocyanine as an efficient agent for photodynamic cancer therapy

- Mfouo-Tynga, Ivan, Abrahamse, Heidi

  • Authors: Mfouo-Tynga, Ivan , Abrahamse, Heidi
  • Date: 2016
  • Subjects: Death mechanisms , Photodynamic cancer therapy , Reactive oxygen species
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/91926 , uj:20163 , Citation: Abrahamse, H. & Mfouo-Tynga, I. 2016. Cell death pathways and phthalocyanine as an efficient agent for photodynamic cancer therapy.
  • Description: Abstract: The mechanisms of cell death can be predetermined (programmed) or not and categorized into apoptotic, autophagic and necrotic pathways. The process of Hayflick limits completes the execution of death-related mechanisms. Reactive oxygen species (ROS) are associated with oxidative stress and subsequent cytodamage by oxidizing and degrading cell components. ROS are also involved in immune responses, where they stabilize and activate both hypoxia-inducible factors and phagocytic effectors. ROS production and presence enhance cytodamage and photodynamic-induced cell death. Photodynamic cancer therapy (PDT) uses non-toxic chemotherapeutic agents, photosensitizer (PS), to initiate a light-dependent and ROS-related cell death. Phthalocyanines (PCs) are third generation and stable PSs with improved photochemical abilities. They are effective inducers of cell death in various neoplastic models. The metallated PCs localize in critical cellular organelles and are better inducers of cell death than other previous generation PSs as they favor mainly apoptotic cell death events.
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Differentiation potential of adipose-derived stem cells when cocultured with smooth muscle cells, and the role of low-intensity irradiation

- Mvula, Bernard, Abrahamse, Heidi

  • Authors: Mvula, Bernard , Abrahamse, Heidi
  • Date: 2016
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/214233 , uj:21254 , Citation: Mvula, B & Abrahamse, H. 2016. Differentiation potential of adipose-derived stem cells when cocultured with smooth muscle cells, and the role of low-intensity irradiation.
  • Description: Abstract: The aim of the study was to investigate the differentiation potential of adipose-derived stem cells (ADSCs) when cocultured with smooth muscle cells (SMCs), and to determine the role of low-intensity laser irradiation (LILI). Background data: ADSCs isolated from adipose tissue are isolated with ease and in large amounts. SMCs constitute most parts of the intestinal, urinary, reproductive, and cardiovascular systems. LILI has been found to have positive effects on different cell types, including ADSCs. Methods: The study used ADSCs (Stempro Adipose Derived Stem Cells-R7788-115) and SMCs (SKU-T-1 American Type Culture Collection HTB-114) cell lines. These cell lines were cocultured in a 1:1 ratio with and without growth factors and then exposed to LILI using 636 nm at 5 J/cm2. Results: Cell viability and proliferation increased significantly in the cocultured groups that were exposed to LILI alone, as well as in combination with growth factors. Further, there was a significant decrease in the expression of stem cell markers with a concomitant increase in SMC markers. Conclusions: These results suggest that ADSCs have the ability to differentiate into SMCs when cocultured with SMCs, whereas LILI potentially augments the differentiation potential and need. This further highlights the significant role that LILI has to offer ADSC therapy in regenerative medicine.
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Effective gold nanoparticle-antibody-mediated drug delivery for photodynamic therapy of lung cancer stem cells

- Crous, Anine, Abrahamse, Heidi

  • Authors: Crous, Anine , Abrahamse, Heidi
  • Date: 2020
  • Subjects: Lung cancer stem cells , Gold nanoparticles , Immunoconjugate
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/415769 , uj:35143 , Citation: Crous, A., Abrahamse, H. Effective gold nanoparticle-antibody-mediated drug delivery for photodynamic therapy of lung cancer stem cells
  • Description: Abstract: , Cancer stem cells (CSCs) are a leading contributor to lung cancer mortality rates. CSCs are responsible for tumor growth and recurrence through inhibition of drug-induced cell death, decreasing the effect of traditional cancer therapy and photodynamic therapy (PDT). PDT can be improved to successfully treat lung cancer by using gold nanoparticles (AuNPs), due to their size and shape, which have been shown to facilitate drug delivery and retention, along with the targeted antibody (Ab) mediated selection of CSCs. In this study, a nanobioconjugate (NBC) was constructed, using a photosensitizer (PS) (AlPcS4Cl), AuNPs and Abs. The NBC was characterized, using spectroscopy techniques. Photodynamic effects of the NBC on lung CSCs was evaluated, using biochemical assays 24 h post-irradiation, in order to establish its anticancer effect. Results showed successful conjugation of the nanocomposite. Localization of the NBC was seen to be in integral organelles involved in cell homeostasis. Biochemical responses of lung CSCs treated using AlPcS4Cl -AuNP and AlPcS4Cl-AuNP-Ab showed significant cell toxicity and cell death, compared to free AlPcS4Cl. The PDT effects were enhanced when using the NBC, showing significant lung CSC destruction to the point of eradication.
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Effective photodynamic therapy for colon cancer cells using Chlorin e6 Coated Hyaluronic acid-based carbon nanotubes

- Sundaram, Prabhavathi, Abrahamse, Heidi

  • Authors: Sundaram, Prabhavathi , Abrahamse, Heidi
  • Date: 2020
  • Subjects: Ccolon cancer , Chlorin e6 , Carbon nanotubes
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/426594 , uj:36597 , Sundaram, P., Abrahamse, H.: Effective photodynamic therapy for colon cancer cells using Chlorin e6 Coated Hyaluronic acid-based carbon nanotubes. DOI:10.3390/ijms21134745
  • Description: Abstract: Colon cancer is the third major cancer contributor to mortality worldwide. Nanosized particles have attracted attention due to their possible contribution towards cancer treatment and diagnosis. Photodynamic therapy (PDT) is a cancer therapeutic modality that involves a light source, a photosensitizer and reactive oxygen species. Carbon nanotubes are fascinating nanocarriers for drug delivery, cancer diagnosis and numerous potential applications due to their unique physicochemical properties. In this study, single walled carbon nanotubes (SWCNTs) were coupled with hyaluronic acid (HA) and chlorin e6 (Ce6) coated on the walls of SWCNTs. The newly synthesized nanobiocomposite was characterized using ultraviolet-visible spectroscopy, Fourier transform electron microscopy (FTIR), X-ray diffraction analysis (XRD), particle size analysis and zeta potential. The loading efficiency of the SWCNTs-HA for Ce6 was calculated. The toxicity of the nanobiocomposite was tested on colon cancer cells using PDT at a fluence of 5 J/cm2 and 10 J/cm2 . After 24 h, cellular changes were observed via microscopy, LDH cytotoxicity assay and cell death induction using annexin propidium iodide. The results showed that the newly synthesized nanobiocomposite enhanced the ability of PDT to be a photosensitizer carrier and induced cell death in colon cancer cells.
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Enhancement of phthalocyanine mediated photodynamic therapy by catechin on lung cancer cells

- Senapathy, Giftson J., George, Blassan P., Abrahamse, Heidi

Evaluation of cell damage induced by irradiated Zinc-Phthalocyanine-gold dendrimeric nanoparticles in a breast cancer cell line

- Mfouo-Tynga, Ivan, Houreld, Nicolette Nadene, Abrahamse, Heidi

Functional silver nanoparticle catalysed [3+] cycloaddition reaction : greener route to substituted-1,2,3-triazolines

- Hemmaragala, Nanjyndaswamy Marishetty, Abrahamse, Heidi, George, Blassan Placktal Adimuriyil, Gannimani, Ramesh, Govender, Patrick

Genetic aberrations associated with photodynamic therapy in colorectal cancer cells

- Abrahamse, Heidi, Houreld, Nicolette Nadene

  • Authors: Abrahamse, Heidi , Houreld, Nicolette Nadene
  • Date: 2019
  • Subjects: Photodynamic therapy, Colorectal cancer, Zinc phthalocyanine;
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/396389 , uj:32909 , Citation : Abrahamse, H. 2019. Genetic aberrations associated with photodynamic therapy in colorectal cancer cells @ Houreld, N.N. , http://dx.doi.org/10.3390/ijms20133254
  • Description: Abstract : Photodynamic therapy (PDT) is a cancer treatment modality that utilizes three components: light (λ 650–750 nm), a photosensitizer (PS) and molecular oxygen, which upon activation renders the modality effective. Colorectal cancer has one of the highest incident rates as well as a high mortality rate worldwide. In this study, a zinc (Zn) metal-based phthalocyanine (ZnPcSmix) PS was used to determine its efficacy for the treatment of colon adenocarcinoma cells (DLD-1 and Caco-2). Photoactivation of the PS was achieved by laser irradiation at a wavelength of 680 nm. Dose responses were performed to establish optimal PS concentration and irradiation fluence. A working combination of 20 µM ZnPcSmix and 5 J/cm2 was used. Biochemical responses were determined after 1 or 24 h incubation post-treatment. Since ZnPcSmix is localized in lysosomes and mitochondria, mitochondrial destabilization analysis was performed monitoring mitochondrial membrane potential (MMP). Cytosolic acidification was determined measuring hydrogen peroxide (H2O2) levels in the cytoplasm. Having established apoptotic cell death induction, an apoptosis PCR array was performed to establish the apoptotic mechanism. In DLD-1 cells, expression of genes included 3 up-regulated and 20 down-regulated genes while in Caco-2 cells, there were 16 up-regulated and 22 down-regulated genes. In both cell lines, in up-regulated genes, there was a combination of pro- and anti-apoptotic genes that were significantly expressed. Gene expression results showed that more tumorigenic cells (DLD-1) went through apoptosis; however, they exhibit increased risk of resistance and recurrence, while less tumorigenic Caco-2 cells responded better to PDT, thus being suggestive of a better prognosis post-PDT treatment. In addition, the possible apoptotic mechanisms of cell death were deduced based on the genetic expression profiling of regulatory apoptotic inducing factors.
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Green synthesis of 5-substituted-1h-1,2,3,4-tetrazoles and 1-sustituted-1h-1,2,3,4-tetrazoles via [3+2] cycloaddition by reusable immobilized alcl3 on γ–al2o3

- Nanjundaswamy, Hemmaragala Marishetty, Abrahamse, Heidi

Identifying plant-based natural medicine against oxidative stress and neurodegenerative disorders

- Chandran, Rahul, Abrahamse, Heidi

In vitro antiproliferative effect of the acetone extract of rubus fairholmianus gard. Root on human colorectal cancer cells

- George, Blassan Plackal Adimuriyil, Tynga, Ivan Mfouo, Abrahamse, Heidi

  • Authors: George, Blassan Plackal Adimuriyil , Tynga, Ivan Mfouo , Abrahamse, Heidi
  • Date: 2016
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/91918 , uj:20162 , Citation: George, B.P.A., Tynga, I.M. & Abrahamse, H. 2016. In vitro antiproliferative effect of the acetone extract of rubus fairholmianus gard. Root on human colorectal cancer cells.
  • Description: Abstract: mechanisms. The effects of root acetone extract of Rubus fairholmianus (RFRA) on the proliferation of human colorectal cancer (Caco-2) cells have been investigated in this study. The extract led to a dose dependent decrease in both viability and proliferation and increased cytotoxicity using trypan blue exclusion, adenosine 5󸀠-triphosphate (ATP), and lactate dehydrogenase (LDH) assay. The morphological features of the treated cells were supportive for the antiproliferative activity. The Annexin V/propidium iodide staining indicated that R. fairholmianus induced toxic effects in Caco-2 cells and the percentages of the early and late apoptotic population significantly increased when compared with control cells. Also we studied the apoptosis inducing ability of the extract by analysing caspase 3/7 activity and the induction of cell death via the effector caspases was confirmed; the activity increased in treated cells compared with control.Thus the present findings highlight that the R. fairholmianus root acetone extract exhibits antiproliferative activity on Caco-2 cells by the induction of apoptosis via caspase dependent pathway.
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In vitro combined effect of Doxorubicin and sulfonated zinc Phthalocyanine– mediated photodynamic therapy on MCF-7 breast cancer cells

- Aniogo, Eric Chekwube, George, Blassan Plackal Adimuriyil, Abrahamse, Heidi

  • Authors: Aniogo, Eric Chekwube , George, Blassan Plackal Adimuriyil , Abrahamse, Heidi
  • Date: 2017
  • Subjects: Doxorubicin , Phthalocyanine , Photodynamic therapy
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/249516 , uj:25966 , Citation: Aniogo, E.C., George, B.P.A. & Abrahamse, H. 2017. In vitro combined effect of Doxorubicin and sulfonated zinc Phthalocyanine– mediated photodynamic therapy on MCF-7 breast cancer cells. Tumor Biology, DOI: 10.1177/1010428317727278
  • Description: Abstract: Doxorubicin is a broad-spectrum antibiotic and anticancer drug used to treat a variety of human malignancies like breast cancer and leukaemia. Unfortunately, a dose-dependent side effect of this drug is common, representing a major obstacle to its use despite its therapeutic efficacy. Photodynamic therapy is an emerging non-invasive potential adjuvant for conventional cancer treatment. In an attempt to circumvent the dose-limiting effect of doxorubicin, this study aimed to investigate cellular anticancer activity of doxorubicin and sulfonated zinc phthalocyanine–mediated photodynamic therapy on MCF-7 cells alone and in combination. Furthermore, we investigated the cell death pathway resulting from the combination treatment. MCF-7 cells were incubated with 0.5 μM concentration of doxorubicin for 20 h, afterwards, various concentrations of sulfonated zinc phthalocyanine were added and incubated for 4 h. Cells were irradiated using a 681.5 nm diode laser at 4.53 mW/cm2 for 18 min 24 s (5 J/cm2). Cell viability and proliferation were measured using trypan blue assay and homogeneous adenosine triphosphate quantitation assay, respectively, while qualitative changes in cellular morphology were observed under inverted light microscopy. Cellular DNA damage was assessed under fluorescent microscopy and Annexin V/propidium iodide stain was used to investigate the cell death pathway. Findings from this study shown that combined treatment with doxorubicin and photodynamic therapy was more effective in inhibiting the proliferation and growth of MCF-7 cells. Overall, the results indicate that combination of smaller dose of doxorubicin with photodynamic therapy is a promising combined treatment strategy for breast carcinoma. However, this combination warrants further investigation.
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Influence of low intensity laser irradiation on isolated human adipose derived stem cells over 72 hours and their differentiation potential into smooth muscle cells using retinoic acid

- Houreld, Nicolette N., Abrahamse, Heidi, De Villiers, Jennifer A.

  • Authors: Houreld, Nicolette N. , Abrahamse, Heidi , De Villiers, Jennifer A.
  • Date: 2011
  • Subjects: Adipose derived stem cells , Stem cells , Low intensity laser irradiation , Cell therapy
  • Type: Article
  • Identifier: uj:5812 , ISSN 1550-8943 , http://hdl.handle.net/10210/7820
  • Description: Human adipose derived stem cells (hADSCs), with their impressive differentiation potential, may be used in autologous cell therapy or grafting to replace damaged tissues. Low intensity laser irradiation (LILI) has been shown to influence the behaviour of various cells, including stem cells. This study aimed to investigate the effect of LILI on hADSCs 24, 48 or 72 h post-irradiation and their differentiation potential into smooth muscle cells (SMCs). Methodology: hADSCs were exposed to a 636 nm diode laser at a fluence of 5 J/cm2. hADSCs were differentiated into SMCs using retinoic acid (RA). Morphology was assessed by inverted light and differential interference contrast (DIC) microscopy. Proliferation and viability of hADSCs was assessed by optical density (OD), Trypan blue staining and adenosine triphosphate (ATP) luminescence. Expression of stem cell markers, β1-integrin and Thy-1, and SMC markers, smooth muscle alpha actin (SM-αa), desmin, smooth muscle myosin heavy chain (SM-MHC) and smoothelin, was assessed by immunofluorescent staining and real-time reverse transcriptase polymerase chain reaction (RT-PCR). Results: Morphologically, hADSCs did not show any differences and there was an increase in viability and proliferation post-irradiation. Immunofluorescent staining showed expression of β1-integrin and Thy-1 72 h post-irradiation. RT-PCR results showed a down regulation of Thy-1 48 h post-irradiation. Differentiated SMCs were confirmed by morphology and expression of SMC markers. Conclusion: LILI at a wavelength of 636 nm and a fluence of 5 J/cm2 does not induce differentiation of isolated hADSCs over a 72 h period, and increases cellular viability and proliferation. hADSCs can be differentiated into SMCs within 14 days using RA.
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Inorganic salts and antimicrobial photodynamic Therapy : mechanistic conundrums?

- Hamblin, Michael R., Abrahamse, Heidi

  • Authors: Hamblin, Michael R. , Abrahamse, Heidi
  • Date: 2018
  • Subjects: Antimicrobial photodynamic inactivation , Potentiation by inorganic salts , Sodium azide
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/289251 , uj:31380 , Citation: Hamblin, M.R. & Abrahamse, H. 2018. Inorganic salts and antimicrobial photodynamic Therapy : mechanistic conundrums?. Molecules 2018, 23, 3190; doi:10.3390/molecules23123190
  • Description: Abstract: We have recently discovered that the photodynamic action of many different photosensitizers (PSs) can be dramatically potentiated by addition of a solution containing a range of different inorganic salts. Most of these studies have centered around antimicrobial photodynamic inactivation that kills Gram-negative and Gram-positive bacteria in suspension. Addition of nontoxic water-soluble salts during illumination can kill up to six additional logs of bacterial cells (one million-fold improvement). The PSs investigated range from those that undergo mainly Type I photochemical mechanisms (electron transfer to produce superoxide, hydrogen peroxide, and hydroxyl radicals), such as phenothiazinium dyes, fullerenes, and titanium dioxide, to those that are mainly Type II (energy transfer to produce singlet oxygen), such as porphyrins, and Rose Bengal. At one extreme of the salts is sodium azide, that quenches singlet oxygen but can produce azide radicals (presumed to be highly reactive) via electron transfer from photoexcited phenothiazinium dyes. Potassium iodide is oxidized to molecular iodine by both Type I and Type II PSs, but may also form reactive iodine species. Potassium bromide is oxidized to hypobromite, but only by titanium dioxide photocatalysis (Type I). Potassium thiocyanate appears to require a mixture of Type I and Type II photochemistry to first produce sulfite, that can then form the sulfur trioxide radical anion. Potassium selenocyanate can react with either Type I or Type II (or indeed with other oxidizing agents) to produce the semi-stable selenocyanogen (SCN)2. Finally, sodium nitrite may react with either Type I or Type II PSs to produce peroxynitrate (again, semi-stable) that can kill bacteria and nitrate tyrosine. Many of these salts (except azide) are non-toxic, and may be clinically applicable.
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