Due to the inevitable reality that most patients diagnosed with cancer will eventually relapse, modern oncology research has been forced to tackle this outcome primitively using combination therapies. Adoptive T-cell transfer with Oncolytic Virus Vaccination represents a new class of combination therapies that can facilitate the crosstalk of multiple aspects of the immune system such that they work in concert to prevent this outcome for many types of cancer. Despite this, immunosuppressive systems like those characterized in the B16F10-gp33 melanoma model pose a new problem for this approach. Typically, this model has total regression but is subsequently followed by relapse. Previous work from the Wan lab has suggested that this may be an outcome of total target gene deletion. Here we present two approaches to tackle this through the targeting of DNA repair pathways of the host cell. Our data can show that both VSV and Vaccinia infection/ propagation does lead to the generation of DNA damage but in the case of VSV this leads to incomplete cell lysis, and ultimately target gene loss via double-stranded DNA repair mechanisms. We were able to tackle the phenomenon following VSV administration by adding DNA repair inhibitors to the mix and showed that the proportion of cells that escaped after the loss of the target antigen was decreased by half when compared to the standard procedures. Additionally, this work also gave a preliminary understanding of how Vaccinia may achieve a similar outcome to this via its unique cytoplasmic replication mechanisms. / Thesis / Master of Science (MSc)

No description available.

Malaria affects about forty percent of the world’s population. Annually more than 1.5 million fatalities due to malaria occur and parasite resistance to existing antimalarial drugs such as mefloquine has already reached disturbingly high levels in South-East Asia and on the African continent. Consequently, there is a dire need for new drugs or formulations in the prophylaxis and treatment of malaria. Artesunate, an artemisinin derivative, represents a new category of antimalarials that is effective against drug-resistant Plasmodium falciparum strains and is of significance in the current antimalarial campaign. As formulating an ACT double fixed-dose combination is technically difficult, it is essential that fixed-dose combinations are shown to have satisfactory ingredient compatibility, stability, and dissolution rates similar to the separate oral dosage forms. Since the general deployment of a combination of artesunate and mefloquine in 1994, the cure rate increased again to almost 100% from 1998 onwards, and there has been a sustained decline in the incidence of Plasmodium falciparum malaria in the experimental studies (Nosten et al., 2000:297; WHO, 2010:17). However, the successful formulation of a solid oral dosage form and fixed dosage combination of artesunate and mefloquine remains both a market opportunity and a challenge. Artesunate and mefloquine both exhibited poor flow properties. Furthermore, different elimination half-lives, treatment dosages as well as solubility properties of artesunate and mefloquine required different formulation approaches. To substantiate the FDA’s pharmaceutical quality by design concept, the double fixed-dose combination of artesunate and mefloquine required strict preliminary formulation considerations regarding compatibility between excipients and between the APIs. Materials and process methods were only considered if theoretically and experimentally proved safe. Infrared absorption spectroscopy (IR) and X-ray powder diffraction (XRPD) data proved compatibility between ingredients and stability during the complete manufacturing process by a peak by peak correlation. Scanning Electron Micrographs (SEM) provided explanations for the inferior flow properties exhibited by the investigated APIs. Particle size analysis and SEM micrographs confirmed that the larger, rounder and more consistently sized particles of the granulated APIs contributed to improved flow under the specified testing conditions. A compressible mixture containing 615 mg of the APIs in accordance with the WHO recommendation of 25 mg/kg of mefloquine taken in two or three divided dosages, and 4 mg/kg/day for 3 days of artesunate for uncomplicated falciparum malaria was developed. Mini-tablets of artesunate and mefloquine were compressed separately and successfully with the required therapeutic dosages and complied with pharmacopoeial standards. Preformulation studies eventually led to a formula for a double fixed-dose combination and with the specific aim of delaying the release of artesunate due to its short half-life. A factorial design revealed the predominant factors contributing to the successful wet granulation of artesunate and mefloquine. A fractional factorial design identified the optimum factors and factor levels. The application of the granulation fluid (20% w/w) proved to be sufficient by a spraying method for both artesunate and mefloquine. A compatible acrylic polymer and coating agent for artesunate, Eudragit® L100 was employed to delay the release of approximately half of the artesunate dose from the double fixed-dose combination tablet until a pH of 6.8. A compressible mixture was identified and formulated to contain 200 mg of artesunate and 415 mg of mefloquine per tablet. The physical properties of the tablets complied with BP standards. An HPLC method from available literature was adapted and validated for analytical procedures. Dissolution studies according to a USP method were conducted to verify and quantify the release of the APIs in the double fixed-dose combination. The initial dissolution rate (DRi) of artesunate and mefloquine in the acidic dissolution medium was rapid as required. The enteric coated fraction of the artesunate exhibited no release in an acidic environment after 2 hours, but rapid release in a medium with a pH of 6.8. The structure of the granulated particles of mefloquine may have contributed to its first order release profile in the dissolution mediums. A linear correlation was present between the rate of mefloquine release and the percentage of mefloquine dissolved (R2 = 0.9484). Additionally, a linear relationship was found between the logarithm of the percentage mefloquine remaining against time (R2 = 0.9908). First order drug release is the dominant release profile found in the pharmaceutical industry today and is coherent with the kinetics of release obtained for mefloquine. A concept pre-clinical phase, double fixed-dose combination solid oral dosage form for artesunate and mefloquine was developed. The double fixed-dose combination was designed in accordance with the WHO’s recommendation for an oral dosage regimen of artesunate and mefloquine for the treatment of uncomplicated falciparum malaria. The specifications of the double fixed-dose combination were developed in close accordance with the FDA’s quality by design concept and WHO recommendations. An HPLC analytical procedure was developed to verify the presence of artesunate and mefloquine. The dissolution profiles of artesunate and mefloquine were investigated during the dissolution studies. / PhD (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

Résumé Introduction L’amlodipine et l’atorvastatine offrent des avantages thérapeutiques au-delà de leur indication primaire, soit la réduction de la pression artérielle et des lipides sanguins, respectivement. L’amlodipine induit l’apoptose des cellules de muscle lisse vasculaire (CMLV) in vivo, contribuant à la régression de l'hypertrophie aortique chez le rat spontanément hypertendu (SHR). L'atorvastatine induit l’apoptose des CMLV in vitro, un effet proportionnel à la dose. Toutefois, cet effet reste à être démontré in vivo. Nous postulons que l’atorvastatine induira la régression de l’hypertrophie aortique via l’apoptose des CMLV chez le SHR, et que la combinaison de l’amlodipine et de l’atorvastatine aura un effet synergique sur la régression de l’hypertrophie aortique via l’apoptose des CMLV chez le SHR. Méthodologie L’amlodipine et l’atorvastatine ont été administrées à des SHR âgés de 11 semaines durant trois ou six semaines, individuellement ou en combinaison. Les points principaux à l'étude étaient le remodelage vasculaire et la pression artérielle. La fragmentation et le contenu en ADN, le stress oxydant, le taux de cholestérol et les niveaux de nitrates ont aussi été mesurés. Résultats Lorsque l’atorvastatine a été administrée seule, une diminution significative du stress oxydant et de la pression artérielle a été observée après trois et six semaines de traitement, respectivement. Par contre, aucune différence n’a pu être décelée quant au remodelage vasculaire. L'amlodipine a réduit la pression artérielle et l'hypertrophie aortique de façon dépendante de la dose. Une diminution significative de l'hyperplasie a été détectée après trois semaines de traitement avec la combinaison, et après six semaines avec une faible dose d'amlodipine. Conclusion Nos résultats ne supportent pas l'hypothèse que l'atorvastatine induit l'apoptose des CMLV in vivo. Par contre, lorsque combinée à l'amlodipine, elle pourrait ajouter un bénéfice supplémentaire au niveau de la réduction de l'hyperplasie aortique. / Abstract Background and purpose Antihypertensive drugs such as the calcium channel blocker (CCB) amlodipine and cholesterol lowering agents such as statins exhibit pleiotropic effects. Amlodipine reduces aortic hypertrophy and hyperplasia in spontaneously hypertensive rat (SHR) by inducing a transient wave of apoptosis. Atorvastatin induces apoptosis of vascular smooth muscle cell (VSMC) in vitro, independently of cholesterol synthesis, an effect that remains to be shown in vivo. The present studies were designed to test the hypothesis that atorvastatin can induce vascular remodeling by VSMC apoptosis in vivo in SHR, and to test whether combined therapy with low dose amlodipine would provide synergistic effects on regression of aortic hypertrophy. Experimental approach 11-week old SHR were given atorvastatin and amlodipine, alone or in combination, for three or six weeks. Primary end-points were vascular remodeling and blood pressure. Secondary end-points included DNA fragmentation and content in the aorta, oxidative stress, cholesterol and serum total nitrite and nitrate (NOx) concentrations. Key results Treatment with atorvastatin did not modify vascular structure, although it significantly reduced oxidative stress after three weeks and blood pressure after six weeks. Amlodipine dose-dependently reduced blood pressure and aortic hypertrophy. Significant reduction of cellular hyperplasia was reached after 6 weeks with a low dose of amlodipine alone or after 3 weeks when atorvastatin was combined with low dose amlodipine. Conclusions and implications Our results do not support the notion that atorvastatin induces VSMC apoptosis in vivo, although the data suggest a possible interaction with amlodipine in reducing VSMC hyperplasia in the hypertensive aorta.

Résumé Introduction L’amlodipine et l’atorvastatine offrent des avantages thérapeutiques au-delà de leur indication primaire, soit la réduction de la pression artérielle et des lipides sanguins, respectivement. L’amlodipine induit l’apoptose des cellules de muscle lisse vasculaire (CMLV) in vivo, contribuant à la régression de l'hypertrophie aortique chez le rat spontanément hypertendu (SHR). L'atorvastatine induit l’apoptose des CMLV in vitro, un effet proportionnel à la dose. Toutefois, cet effet reste à être démontré in vivo. Nous postulons que l’atorvastatine induira la régression de l’hypertrophie aortique via l’apoptose des CMLV chez le SHR, et que la combinaison de l’amlodipine et de l’atorvastatine aura un effet synergique sur la régression de l’hypertrophie aortique via l’apoptose des CMLV chez le SHR. Méthodologie L’amlodipine et l’atorvastatine ont été administrées à des SHR âgés de 11 semaines durant trois ou six semaines, individuellement ou en combinaison. Les points principaux à l'étude étaient le remodelage vasculaire et la pression artérielle. La fragmentation et le contenu en ADN, le stress oxydant, le taux de cholestérol et les niveaux de nitrates ont aussi été mesurés. Résultats Lorsque l’atorvastatine a été administrée seule, une diminution significative du stress oxydant et de la pression artérielle a été observée après trois et six semaines de traitement, respectivement. Par contre, aucune différence n’a pu être décelée quant au remodelage vasculaire. L'amlodipine a réduit la pression artérielle et l'hypertrophie aortique de façon dépendante de la dose. Une diminution significative de l'hyperplasie a été détectée après trois semaines de traitement avec la combinaison, et après six semaines avec une faible dose d'amlodipine. Conclusion Nos résultats ne supportent pas l'hypothèse que l'atorvastatine induit l'apoptose des CMLV in vivo. Par contre, lorsque combinée à l'amlodipine, elle pourrait ajouter un bénéfice supplémentaire au niveau de la réduction de l'hyperplasie aortique. / Abstract Background and purpose Antihypertensive drugs such as the calcium channel blocker (CCB) amlodipine and cholesterol lowering agents such as statins exhibit pleiotropic effects. Amlodipine reduces aortic hypertrophy and hyperplasia in spontaneously hypertensive rat (SHR) by inducing a transient wave of apoptosis. Atorvastatin induces apoptosis of vascular smooth muscle cell (VSMC) in vitro, independently of cholesterol synthesis, an effect that remains to be shown in vivo. The present studies were designed to test the hypothesis that atorvastatin can induce vascular remodeling by VSMC apoptosis in vivo in SHR, and to test whether combined therapy with low dose amlodipine would provide synergistic effects on regression of aortic hypertrophy. Experimental approach 11-week old SHR were given atorvastatin and amlodipine, alone or in combination, for three or six weeks. Primary end-points were vascular remodeling and blood pressure. Secondary end-points included DNA fragmentation and content in the aorta, oxidative stress, cholesterol and serum total nitrite and nitrate (NOx) concentrations. Key results Treatment with atorvastatin did not modify vascular structure, although it significantly reduced oxidative stress after three weeks and blood pressure after six weeks. Amlodipine dose-dependently reduced blood pressure and aortic hypertrophy. Significant reduction of cellular hyperplasia was reached after 6 weeks with a low dose of amlodipine alone or after 3 weeks when atorvastatin was combined with low dose amlodipine. Conclusions and implications Our results do not support the notion that atorvastatin induces VSMC apoptosis in vivo, although the data suggest a possible interaction with amlodipine in reducing VSMC hyperplasia in the hypertensive aorta.

Malaria affects about forty percent of the world’s population. Annually more than 1.5 million fatalities due to malaria occur and parasite resistance to existing antimalarial drugs such as mefloquine has already reached disturbingly high levels in South-East Asia and on the African continent. Consequently, there is a dire need for new drugs or formulations in the prophylaxis and treatment of malaria. Artesunate, an artemisinin derivative, represents a new category of antimalarials that is effective against drug-resistant Plasmodium falciparum strains and is of significance in the current antimalarial campaign. As formulating an ACT double fixed-dose combination is technically difficult, it is essential that fixed-dose combinations are shown to have satisfactory ingredient compatibility, stability, and dissolution rates similar to the separate oral dosage forms. Since the general deployment of a combination of artesunate and mefloquine in 1994, the cure rate increased again to almost 100% from 1998 onwards, and there has been a sustained decline in the incidence of Plasmodium falciparum malaria in the experimental studies (Nosten et al., 2000:297; WHO, 2010:17). However, the successful formulation of a solid oral dosage form and fixed dosage combination of artesunate and mefloquine remains both a market opportunity and a challenge. Artesunate and mefloquine both exhibited poor flow properties. Furthermore, different elimination half-lives, treatment dosages as well as solubility properties of artesunate and mefloquine required different formulation approaches. To substantiate the FDA’s pharmaceutical quality by design concept, the double fixed-dose combination of artesunate and mefloquine required strict preliminary formulation considerations regarding compatibility between excipients and between the APIs. Materials and process methods were only considered if theoretically and experimentally proved safe. Infrared absorption spectroscopy (IR) and X-ray powder diffraction (XRPD) data proved compatibility between ingredients and stability during the complete manufacturing process by a peak by peak correlation. Scanning Electron Micrographs (SEM) provided explanations for the inferior flow properties exhibited by the investigated APIs. Particle size analysis and SEM micrographs confirmed that the larger, rounder and more consistently sized particles of the granulated APIs contributed to improved flow under the specified testing conditions. A compressible mixture containing 615 mg of the APIs in accordance with the WHO recommendation of 25 mg/kg of mefloquine taken in two or three divided dosages, and 4 mg/kg/day for 3 days of artesunate for uncomplicated falciparum malaria was developed. Mini-tablets of artesunate and mefloquine were compressed separately and successfully with the required therapeutic dosages and complied with pharmacopoeial standards. Preformulation studies eventually led to a formula for a double fixed-dose combination and with the specific aim of delaying the release of artesunate due to its short half-life. A factorial design revealed the predominant factors contributing to the successful wet granulation of artesunate and mefloquine. A fractional factorial design identified the optimum factors and factor levels. The application of the granulation fluid (20% w/w) proved to be sufficient by a spraying method for both artesunate and mefloquine. A compatible acrylic polymer and coating agent for artesunate, Eudragit® L100 was employed to delay the release of approximately half of the artesunate dose from the double fixed-dose combination tablet until a pH of 6.8. A compressible mixture was identified and formulated to contain 200 mg of artesunate and 415 mg of mefloquine per tablet. The physical properties of the tablets complied with BP standards. An HPLC method from available literature was adapted and validated for analytical procedures. Dissolution studies according to a USP method were conducted to verify and quantify the release of the APIs in the double fixed-dose combination. The initial dissolution rate (DRi) of artesunate and mefloquine in the acidic dissolution medium was rapid as required. The enteric coated fraction of the artesunate exhibited no release in an acidic environment after 2 hours, but rapid release in a medium with a pH of 6.8. The structure of the granulated particles of mefloquine may have contributed to its first order release profile in the dissolution mediums. A linear correlation was present between the rate of mefloquine release and the percentage of mefloquine dissolved (R2 = 0.9484). Additionally, a linear relationship was found between the logarithm of the percentage mefloquine remaining against time (R2 = 0.9908). First order drug release is the dominant release profile found in the pharmaceutical industry today and is coherent with the kinetics of release obtained for mefloquine. A concept pre-clinical phase, double fixed-dose combination solid oral dosage form for artesunate and mefloquine was developed. The double fixed-dose combination was designed in accordance with the WHO’s recommendation for an oral dosage regimen of artesunate and mefloquine for the treatment of uncomplicated falciparum malaria. The specifications of the double fixed-dose combination were developed in close accordance with the FDA’s quality by design concept and WHO recommendations. An HPLC analytical procedure was developed to verify the presence of artesunate and mefloquine. The dissolution profiles of artesunate and mefloquine were investigated during the dissolution studies. / PhD (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

L'efficacité du rtPA dans le traitement de l’ischémie aigue est bien reconnue avec des effets secondaires graves nécessitant l’évaluation d’autres stratégies. Un modèle d’ischémie cérébrale focale a été décrit, réalisé par injection in situ de thrombine. Dans notre première étude, nous avons utilisé l’imagerie par résonance magnétique multimodale pour documenter les lésions et les zones de pénombre dans ce modèle. Malgré une occlusion de l’artère reproductible et une hypoperfusion marquée chez tous les sujets, une reperfusion spontanée est constatée dans 38% des cas, rendant l’IRM incontournable dans l’évaluation de ce modèle. La deuxième étude a comparé l'efficacité d’un TAFI inhibiteur seul ou en combinaison avec le rtPA à faible dose. Nous avons montré que la combinaison du TAFI inhibiteur avec le rtPA à faible dose n'est pas aussi efficace que la dose standard de rtPA, avec une tendance positive, tandis que le TAFI inhibiteur seul n'est pas efficace du tout. Le modèle thromboembolique présente un intérêt particulier dans l'évaluation des stratégies thérapeutiques associées au rtPA pour améliorer la thrombolyse, surtout lorsqu'il est évalué par un suivi longitudinal en IRM / The benefit of recombinant tissue plasminogen activator (rtPA) treatment in stroke is well known with serious side effects requiring the evaluation of alternative strategies. Injection of thrombin in the middle cerebral artery of mice has been proposed as a new model of thromboembolic stroke. In the first study, we used multiparametric Magnetic Resonance Imaging (MRI), performed immediately after thrombin injection, to document occlusion and area at risk in this model. Despite similar MCA occlusion and marked hypoperfusion, half of animals showed a cortical lesion on DWI, while the other half demonstrated no or very limited lesion. Therefore, MRI measurement of basal lesion size is required to use this animal model in therapeutic studies. The second study compared efficacy between TAFI inhibitor alone and TAFI inhibitor in combination with low-dose rtPA. In conclusion, we showed that the combination of TAFI-I with low-dose rtPA is not as effective as the standard dose of rtPA, with a positive trend, while TAFI inhibition alone is not effective at all. The present thromboembolic model is of particular interest in assessing strategies rtPA association to improve thrombolysis, especially when coupled with longitudinal MRI assessment

No description available.

Cancer is a leading cause of death that affects millions of people across the globe each year. Photodynamic therapy (PDT) is a relatively new treatment approach for cancer in which anticancer drugs are activated by light at an appropriate wavelength to generate highly cytotoxic reactive oxygen species (ROS) and achieve tumor destruction. Compared with conventional chemo- and radiotherapy, PDT can be performed with minimal invasiveness, local targeting and reduced side effects. However, most of the currently available PDT drugs mainly absorb in the visible part of the spectrum, where light penetration depth into human tissues is very limited. Therefore, increasing the treatment depth of PDT has been considered to be an important approach to improve the effectiveness of PDT for treating larger and thicker tumor masses. In this thesis, we present our investigation into the potential of two-photon activated PDT (2-γ PDT), combination therapy of PDT and chemotherapy, and bioluminescence-activated PDT as a means to increase the treatment depth of this modality. In 2-γ PDT, the photosensitizing agents are activated through simultaneous absorption of two photons. This approach allows the use of near-infrared (NIR) light that can penetrate deeper into tissues and thus, has the potential of treating deep-seated tumors and reducing side effects, while the non-linear nature of two-photon excitation (TPE) may improve tumor targeting. We have evaluated the PDT efficacy of a second-generation photosensitizer derived from chlorophyll a, pyropheophorbide a methyl ester (MPPa), through both one- and two-photon activation. We observed that MPPa had high one-photon (1-γ PDT efficacy against both cisplatin-sensitive human cervical (HeLa) and cisplatin-resistant human lung (A549) and ovarian (NIH:OVCAR-3) cancer cells when activated by femtosecond (fs) laser pulses at 674 nm. At a low light dose of 0.06 J cm-2, the MPPa concentration required to produce a 50% cell killing effect (IC50) was determined to be 5.3 ± 0.3, 3.4 ± 0.3 and 3.6 ± 0.4 μM in HeLa, A549 and NIH:OVCAR-3 cells, respectively. More significantly, we also found that MPPa could be effectively activated at the optimal tissue-penetrating wavelength of 800 nm through TPE. At a light dose of 886 J cm-2, where no measurable photodamage was observed in the absence of MPPa, the IC50 values were measured to be 4.1 ± 0.3, 9.6 ± 1.0 and 1.6 ± 0.3 μM in HeLa, A549 and NIH:OVCAR-3 cells, respectively. We obtained corresponding LD50 (the light dose required to produce a 50% killing effect) values of 576 ± 13, 478 ± 18 and 360 ± 16 J cm-2 for 10 μM MPPa, which were approximately 3-5 times lower than the published 2-γ LD50 of Visudyne® and 20-30 times lower than that of Photofrin®. These results indicate that MPPa may serve as a photosensitizer for both 1- and 2-γ activated PDT treatment of difficult-to-treat tumors by conventional therapies. Indocyanine green (ICG), a dye having an absorption maximum near 800 nm, has been considered to be a potential NIR PDT agent. However, the PDT efficacy of ICG has been found to be very limited probably due to the low yield of cytotoxic ROS. In the present work, we have evaluated the combination effects of ICG-mediated PDT with conventional chemotherapy mediated by two types of chemotherapeutic drugs, namely the type II topoisomerase (TOPII) poisons etoposide (VP-16)/teniposide (VM-26) and the platinum-based drugs cisplatin (CDDP)/oxaliplatin (OXP). Synergistic enhancement of cytotoxicity and increased yields of DNA double strand breaks (DSBs) were observed in HeLa, A549 and NIH:OVCAR-3 cancer cells treated with the combination of ICG-PDT and VP-16. The presence of VP-16 during the laser irradiation process was found to be critical for producing a synergistic effect. An electron-transfer-based mechanism, in which ICG could increase the yield of highly cytotoxic VP-16 metabolites, was proposed for the observed synergistic effects, although direct spectroscopic detection of the reaction products was found to be very challenging. Moreover, we observed a much lower degree of synergy in the human normal fibroblast GM05757 cells than that in the three cancer cell lines investigated. Synergistic effects were also observed in A549 cells treated with the combination of ICG-PDT and VM-26 (i.e. an analog of VP-16). Furthermore, the combination of low-dose CDDP/OXP and ICG-PDT was demonstrated to produce an additive or synergistic effect in selected cancer cell lines. These preliminary results suggest that the combination of ICG-PDT with VP-16/VM-26 or CDDP/OXP chemotherapy may offer the advantages of enhancing the therapeutic effectiveness of ICG-PDT and lowering the side effects associated with the chemotherapeutic drugs. Bioluminescence, the generation of light in living organisms through chemical reactions, has been explored as an internal light source for PDT in recent years. This approach, in principle, does not suffer from the limited tissue penetration depth of light. In the present project, we have evaluated the effectiveness of luminol bioluminescence in activating the porphyrin photosensitizers meso-tetra(4-sulfonatophenyl)porphine dihydrochloride (TPPS4) and Fe(III) meso-tetra(4-sulfonatophenyl)porphine chloride (FeTPPS). The combination treatment induced significant killing of HeLa cells, while additive effects were observed in two normal human fibroblast cell lines (GM05757 and MRC-5). Our observations indicate that bioluminescence of luminol may generate sufficient light for intracellular activation of PDT sensitizers. Furthermore, the combination treatment may have intrinsic selectivity towards cancerous tissues. In summary, we have demonstrated effective killing of cancer cells by MPPa-mediated 1- and 2-γ PDT, combination of ICG-PDT and VP-16/VM-26 or CDDP/OXP chemotherapy, and bioluminescence of luminol activated PDT mediated by TPPS4/FeTPPS. These positive preliminary results indicate that all these three approaches have the potential of increasing the treatment depth of PDT and facilitating the development of more effective PDT treatment strategies.

In preclinical research on Alzheimer's disease pharmacotherapy, attention is paid to multipotent compounds, enabling intensification of the effect by targeting multiple pathophysiological mechanisms. The aim of the thesis was to assess the effect of multipotent compounds and combination therapy in models of cognitive deficit in the rat. The mechanism of action of the tested compounds was modulation of neurotransmitter systems. The aim of the first part of the study was to compare the effect of experimental monotherapy and combination therapy with an N-methyl-D-aspartate (NMDA) receptor antagonist and a γ-aminobutyric acid type A (GABAA) receptor positive modulator in the trimethyltin-induced model. Superiority of the combination therapy was proven by histological analysis of hippocampal neurodegeneration; however, it did not reach statistical significance in the cognitive test. The other part of the thesis focused on multipotent tacrine derivatives. We demonstrated a positive effect of 6- chlorotacrine-6-nitrobenzothiazole hybrid, as well as 6-chlorotacrine-L-tryptophan hybrid, acting as acetylcholinesterase inhibitors, in the scopolamine-induced model of cognitive deficit. Besides, we demonstrated a low risk of serious side effects of other tacrine derivatives acting as NMDA receptor antagonists....