A thesis submitted to the faculty of Science, University of the Witwatersrand, in fulfillment of the degree of Doctor of Philosophy in Science Johannesburg, 2012 / Platinum is nowadays one of the best and widely used antitumor agents in cancer chemotherapy. The numerous performances reported by many previous researchers for this metal in the fight against several malignancies led to the synthesis of many platinum complexes. However, the clinical responses related to these complexes led to the development of non-platinum compounds with metal ions which exhibit antitumor activity. Ferrocene is one of them, owing the high consideration inter alia to its environmental oxidore-ductive behavior. Methotrexate is another clinically used anticancer drug worthy to be mentioned. With a structure very close to that of folic acid, differing from it by an amine function and a methyl group, respectively, instead of an hydrogen and an hydroxyl group on the folate, methotrexate has been considered as an antagonist of folic acid by its mechanism of action in the biological environment. It has, together with platinum and non-platinum complexes, shown notorious side-effects by fighting both normal and abnormal cells despite their antineoplastic potency. This is the reason why a drug delivery system is considered as a tool to improve metal complexes and other drugs selectivity for cancer cells. The strategy of enhancing the potency of non-polymeric chemically, physically, or biologically active compounds through the expediency of binding such compounds to a polymeric carrier has revolutioned numerous technologies. In the present thesis is demonstrated the synthesis of several water-soluble macromolecular drug carriers intended for biomedical applications, and the anchoring of platinum to ferrocene-containing antineoplastic agents on one side, then to methotrexate-containing antineoplastic agents on the other side, resulting in a co-conjugate or a conjugate bearing two different drugs on a single carrier. This multidrug anchoring offers the advantage to exploit the potency of two different drugs on a single polymeric structure, each drug having its own pharmacokinetic path. Platinum is the common drug, while ferrocene and methotrexate are the various co-drugs. This order of having the platinum imparted to the polymeric carrier after the two drugs above mentioned were adopted in obedience to the strategy of having the most synthetically demanding drug incorporated in the carrier before the least one. Anchoring of the three drugs to polymeric structures was achieved in aqueous environment. Methotrexate (MTX) and ferrocene (Fc) binding were achieved via HBTU as coupling agent. In all cases, more or less, but very close to, 100% drug loading could be achieved under careful control of experimental conditions. The water-soluble polymeric carriers used are copolyaspartamides, prepared by an aminolytic ring-opening process of polysuccinimide, and copoly(amidoamines) obtained by Michael polyaddition of methylenebisacrylamide (MBA). These polymers were designed to bear amine, hydroxyl or carboxylic acid functional groups in their structure, either as part of the main chain or side chain. The functional groups herein mentioned are important for the coupling of the chemically modified drug species. Exploratory in-vitro biological studies are discussed, as the co-conjugation of the metallic antineoplastic drug, ferrocene and the antifolate methotrexate, each with the metallic drug platinum, is performed. The results of these preliminary tests show that polymer-drug conjugates and co-conjugates can play a role in future cancer therapy.

Background: The D-Dimer test has a high negative predictive value used primarily to exclude clinically suspected possible thrombo-embolic disease. In Emergency Unit (EU) practice, this test is often done not only for suspected Pulmonary Emboli (PE) but also to rule out atypical PE. In South Africa, diagnostic usefulness of this test has not been evaluated in a private hospital EU. The health profile of patients presenting in public and private EUs is different and therefore, it was hypothesized that the usefulness of the DDimer test in these two settings may be different. Results of this study may inform private hospital EU best practice in the optimal utilization of this test. Objective: To evaluate the usefulness of the D-Dimer test in the diagnosis of PE at the Morningside MediClinic (MMC) private hospital EU in Johannesburg, South Africa. Patients and Methods: After approval by the University of the Witwatersrand Human Research Ethics Committee, audit of clinical records was done at the MMC EU from 1 March to 1 June 2009. Informed consent was not required from study subjects as the study was done retrospectively with data extracted from clinical records in an anonymous and delinked fashion. The study population included all patients who had a D-Dimer test done in the MMC EU as part of their diagnostic workup. Extracted data included demographic information, diagnoses and confirmatory tests done. Continuous and categorical variables of data collected were summarized using Stastistica version 9.0 statistical package. A Wells Score was calculated according to the Wells Criteria. Results: In the study period, 189 of 2948 (5%) patients seen at MMC EU had D-Dimers measured. Their population mean age was 57 years (range 38 – 84 years) and 51% were males. Positive D-Dimers were present in 40 (21%) of the total patient population sample group (189 patients). Within the diagnostic categories, the following percentages were the results found per category of the positive D-Dimers within each category: PE (5)(100%), Chest Infection (5)(56%), AMI (2)(33%), Arrhythmia (2)(33%), Hypertension (2)(25%), Chest Pain (6)(14%), Anxiety (3)(23%), Headache (1)(14%), Syncope (1)(14%) and Others (13)(32%). The mean Wells Score in PE was 3.6 (3.0-4.5.) indicating medium probability of PE. All other diagnostic groups had low probability Wells Scores. It was impossible to comment on findings in public hospitals, as there is no known literature found to date on an audit performed concerning the usefulness of the D-Dimer test in a public hospital or any of the public sector, in Johannesburg or elsewhere in South Africa, regarding the diagnosis of PE. However, data has been published by other countries regarding the D-Dimer in various hospital and EU settings (public and private). Conclusion: In the cohort, the D-Dimer was done in only a fifth of patients seen at the private MMC EU and it was positive in less than half of cases. The test yield was highest in PE and had high negative predictive value in more than half of non-PE diagnoses. Therefore, the results suggested that a positive D-Dimer is highly predictive of a diagnosis of PE in this private EU. A negative D-Dimer result appears to be largely associated with any of the non PE wide differential of diagnoses.

Student Number : 9906314R - MSc dissertation - School of Pathology - Faculty of Science / Inappropriate use of antimicrobial agents has been shown to select for organisms with resistance mechanisms (eg. efflux pumps), which could lead to the development of antibiotic resistance. The objective of this study was to investigate a possible link between antibiotic resistant gastrointestinal pathogens and reduced susceptibility to anti microbial agents found in commonly used household disinfectants. Tetracycline and ofloxacin resistant and sensitive Salmonella and E.coli species were isolated from fresh poultry and clinical samples. Ethidium bromide accumulation assays were performed to assess the presence of active efflux pumps. Using spectrophotometric accumulation assays, the extrusion of the active components of commercial household agents by the efflux pumps was tested. To determine changes in the efficacy of these products, in-use disinfectant testing was performed. Active efflux pumps and extrusion of the active ingredients was observed in the resistant but not in the sensitive organisms. When the household products were used at the recommended concentrations, a significant reduction of both resistant and sensitive bacteria was observed after the in-use disinfectant testing procedure. However, if the household products were used at concentrations below the recommended concentration, the resistant bacteria were not eliminated as efficiently as the sensitive bacteria.

Lau Chun Fat. / Bibliography: leaves 83-97 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

by Chung-wing Chau. / Bibliography: leaves 170-183 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

by Leung Shui On. / Bibliography: leaves 161-172 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986

by Kay-Pong Yip. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986. / Bibliography: leaves 77-89

by Cheung Kwok Keung Bobbie. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 128-147.

by Poon Suet Ping, Cycles. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1981. / Bibliography: leaves 117-129.

by Wong Yick Fu. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 201-224. / Acknowledgments --- p.V / Summary --- p.vi / Publications --- p.ix / Statement of Originality --- p.X / List of Abbreviations --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Preamble --- p.2 / Chapter 1.2 --- History of Trichosanthin --- p.6 / Chapter 1.3 --- Preparation of Trichosanthin --- p.8 / Chapter 1.4 --- Chemistry of Trichosanthin --- p.10 / Chapter 1.4.1 --- Primary structure --- p.10 / Chapter 1.4.2 --- Three dimensional structure --- p.12 / Chapter 1.5 --- Pharmacology of Trichosanthin --- p.14 / Chapter 1.5.1 --- Pharmacologic action --- p.14 / Chapter 1.5.2 --- Pharmacokinetics --- p.18 / Chapter 1.5.3 --- Toxicity --- p.21 / Chapter 1.6 --- Clinical Use of Trichosanthin --- p.24 / Chapter 1.6.1 --- Clinical application --- p.24 / Chapter 1.6.2 --- Mechanism of action --- p.29 / Chapter 1.6.3 --- Adverse reactions --- p.31 / Chapter 1.6.4 --- Contraindications --- p.33 / Chapter 1.7 --- Objectives of Project and Organization of Thesis --- p.35 / Chapter Chapter 2 --- Anti-tumour Activity of Trichosanthin In Vitro and In Vivo --- p.37 / Chapter 2.1 --- Cytotoxic Effects of Trichosanthin on Cultured Tumour Cells --- p.38 / Chapter 2.1.1 --- Introduction --- p.38 / Chapter 2.1.2 --- Materials and methods --- p.40 / Chapter 2.1.3 --- Results --- p.49 / Chapter 2.1.4 --- Discussion --- p.59 / Chapter 2.2 --- Effects of Trichosanthin on Co-cultured Cell Lines In Vitro --- p.64 / Chapter 2.2.1 --- Introduction --- p.64 / Chapter 2.2.2 --- Materials and methods --- p.65 / Chapter 2.2.3 --- Results --- p.66 / Chapter 2.2.4 --- Discussion --- p.77 / Chapter 2.3 --- Combination Effects of Trichosanthin with Adriamycin and Cisplatin on Cultured Tumour Cells --- p.80 / Chapter 2.3.1 --- Introduction --- p.80 / Chapter 2.3.2 --- Materials and methods --- p.81 / Chapter 2.3.3 --- Results --- p.84 / Chapter 2.3.4 --- Discussion --- p.93 / Chapter 2.4 --- Effects of Trichosanthin on Choriocarcinoma Cells In Vivo --- p.96 / Chapter 2.4.1 --- Introduction --- p.96 / Chapter 2.4.2 --- Materials and methods --- p.97 / Chapter 2.4.3 --- Results --- p.101 / Chapter 2.4.4 --- Discussion --- p.107 / Chapter 2.5 --- Effects of Trichosanthin Protein and Polysaccharide on Choriocarcinoma Cells In Vitro --- p.110 / Chapter 2.5.1 --- Introduction --- p.110 / Chapter 2.5.2 --- Materials and methods --- p.112 / Chapter 2.5.3 --- Results --- p.114 / Chapter 2.5.4 --- Discussion --- p.117 / Chapter Chapter 3 --- Mechanism of Action of Trichosanthin on Tumour Cells --- p.119 / Chapter 3.1 --- Morphological Study of Effects of Trichosanthin on Cultured Choriocarcinoma Cells --- p.120 / Chapter 3.1.1 --- Introduction --- p.120 / Chapter 3.1.2 --- Materials and methods --- p.121 / Chapter 3.1.3 --- Results --- p.124 / Chapter 3.1.4 --- Discussion --- p.133 / Chapter 3.2 --- Binding of Radiolabelled Trichosanthin with Tumour Cells In Vitro --- p.137 / Chapter 3.2.1 --- Introduction --- p.137 / Chapter 3.2.2 --- Materials and methods --- p.138 / Chapter 3.2.3 --- Results --- p.146 / Chapter 3.2.4 --- Discussion --- p.154 / Chapter 3.3 --- Effects of Trichosanthin on Macromolecule Synthesis of Choriocarcinoma Cells In vitro --- p.159 / Chapter 3.3.1 --- Introduction --- p.159 / Chapter 3.3.2 --- Materials and methods --- p.160 / Chapter 3.3.3 --- Results --- p.163 / Chapter 3.3.4 --- Discussion --- p.167 / Chapter Chapter 4 --- General Discussion --- p.169 / Chapter 4.1 --- Anti-tumour Activity of Trichosanthin --- p.170 / Chapter 4.2 --- Mechanism of Action of Trichosanthin --- p.180 / Chapter 4.3 --- Prospects of Research on Trichosanthin --- p.195 / References --- p.201 / Appendix 1 --- p.225 / Appendix 2 --- p.242