Thesis (M.Cur) --University of Limpopo, 2011 / The aim of this study was to determine the factors that contribute to the increase in the number of tuberculosis (TB) patients in Mpumalanga Province, and to develop guidelines and recommendations to address the challenges of this health issue. The design of the study was qualitative phenomenological. The population consisted of all TB patients who were receiving treatment either at the intensive or the continuation phase. The sampling method was purposive and the sample size comprised 20 participants, of whom 10 were drawn from Shatale clinic at Bushbuckridge, and 10 from Mashishing clinic at Thabachweu municipalities in the Ehlanzeni district of Mpumalanga Province. The data was gathered by means of semi-structured interviews. Data analysis was performed, from which themes and categories were derived. This study revealed several factors that contributed to the increase in the number of TB patients at the study sites. The factors considered most important in this study were the general lack of knowledge of TB among participants, despite their various levels of education, poverty, overcrowding, poor ventilation in the shacks and Reconstruction and Development Program (RDP) houses, unemployment, lack of support while taking treatment, religious and ritual beliefs, and the influence of traditional healers who dispense herbal medicines with the dictum that participants have been possessed by evil spirits and witches. The majority of patients developed TB as a secondary opportunistic infection because of their HIV-positive status, and lack of capacity to practice personal hygiene and proper infection control. Guidelines, strategies and recommendations were formulated to address these public health challenges in the context nursing education, research, administration and practice

This dissertation assesses the factors that lead to the emergence of infectious diseases in children, particularly the emergence of multidrug-resistant organisms (MDROs) and diarrheal pathogens in vulnerable pediatric populations. It includes three manuscripts. The initial study is a systematic review that summarized the role of antibiotic exposure on the acquisition of MDROs in children. Twenty-nine studies met the inclusion criteria and a positive association between prior antibiotic use and subsequent colonization or infection with an MDRO was identified in most studies. There were wide variations among study sites, populations, and definitions of antibiotic use and MDROs. Therefore, limited inferences could be made on which components of antibiotic exposure have the greatest impact on MDRO development. The second analysis examines the relationship between prior stay at a pediatric long-term care (LTC) facility and infection with an MDRO among hospitalized children. This study included 2,945 infections in 258,664 pediatric admissions from 2006 through 2016. At least 1 MDRO was identified in 10% of infections. Of the 1,198 children who had previously resided in a pediatric LTC facility, only 1 child (0.08%) had an MDRO infection. However, prior receipt of pediatric LTC was associated with an increased likelihood of infection (OR 2.4, CI95 1.66 – 3.43), C. difficile infection (OR 2.57, CI95 1.26 – 5.25), days of antibiotic use (OR 1.01, CI95 1.01 – 1.02), length of stay (OR 1.01, CI95 1.01 – 1.01), and death (OR 4.38, CI95 2.93 – 6.55). The concluding study evaluates the association between animals living in or near the home and diarrheal disease in children. This research is a secondary analysis of the Global Enteric Multicenter Study case control study, which investigated the epidemiology of diarrheal illness in children <5 in sub-Saharan Africa and south Asia. Of 9,439 cases and 13,128 controls, 87% had ≥1 animal in their home. In a multivariable analysis adjusting for exclusive breastfeeding, water source, sanitation facility, number of children <5 years in the household, and wealth index, any animal on a child’s compound decreased the odds of diarrhea by 33% (aOR 0.66, CI95 0.59 – 0.74). However, children with diarrhea who had an animal present were not more likely to have a positive stool culture. Overall, the three studies provide a thorough analysis of several factors associated with the infectious disease emergence in children, particularly as related to MDROs and diarrheal disease. Environmental characteristics, including antibiotic use and interaction with animals, were shown to be important factors for emergent infectious disease across diverse settings. The development of pediatric infection prevention interventions should take into consideration environmental risk factors in order to effectively mitigate the risks posed infectious disease emergence.

Orientador: James Venturini / Resumo: Devido ao crescente isolamento de espécimes de Klebsiella pneumoniae resistentes a praticamente todas as classes de drogas antimicrobianas, a busca por novas drogas que sejam alternativa terapêutica para o tratamento das infecções por eles causadas se torna relevante. Nesse contexto, a complexação de íons metálicos a drogas antimicrobianas é uma das abordagens empregadas, uma vez que é possível gerar novas drogas com atividade superior as drogas já existentes. No presente estudo, foi realizada a síntese de metalofármaco por reação de coordenação entre sulfato de polimixina B e cobre (II). O produto desta reação foi caracterizado e sua atividade antimicrobiana frente a espécimes de K. pneumoniae resistentes aos carbapenêmicos e à polimixina B foi avaliada. Os resultados demonstraram que as concentrações inibitórias mínimas (MIC) do complexo sintetizado foram menores em relação aos MICs de polimixina B para 44,44% dos espécimes avaliados; para 33,33% dos espécimes os MIC’s foram equivalentes, e para 22,23% dos espécimes os MIC’s do complexo foram superiores aos MIC’s da polimixina B. Esses resultados são promissores, uma vez que houve um incremento na atividade bacteriana da polimixina complexada ao metal para quase metade dos espécimes avaliados, mostrando que a síntese de novas drogas antimicrobianas através da complexação de íons metálicos é uma técnica que deve ser mais explorada. Além disso, nossos resultados devem conduzir a novos estudos que visem a melhor compreensão da... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to the increasing isolation of Klebsiella pneumoniae specimens resistant to virtually all classes of antimicrobial drugs, the research for new drugs that are alternative therapeutics for the treatment of infections caused by them becomes relevant. In this context, the complexation of metal ions to antimicrobial drugs is one of the approaches used, since it is possible to generate new drugs with higher activity than existing drugs. In the present study, metallodrugs synthesis was performed by a coordination reaction between polymyxin B sulfate and copper (II). The product of this reaction was characterized and its antimicrobial activity against specimens of K. pneumoniae resistant to carbapenems and polymyxin B was evaluated. The results showed that the minimum inhibitory concentrations (MIC) of the synthesized complex were lower than the polymyxin B MICs for 44.44% of the evaluated specimens; for 33.33% of the specimens the MICs were equivalent, and for 22.23% of the specimens the MICs of the complex were superior to the MICs of polymyxin B. These results are encouraging, since there was an increase in the bacterial activity of metal complexed polymyxin for almost half of the evaluated specimens, showing that the synthesis of new antimicrobial drugs through the complexation of metallic ions is a technique that should be further explored. In addition, our results should lead to further studies aiming to a better understanding of the structure, mechanisms of action, toxicit... (Complete abstract click electronic access below) / Mestre

The development of resistance to chemotherapeutic drugs is the main obstacle to the successful treatment of many cancers, including childhood neuroblastoma, the most common solid tumour of infants. One factor that may play a role in determining response of neuroblastoma tumours to therapeutic agents is the p53 tumour suppressor gene. A number of previous studies have suggested that this tumour suppressor protein is inactive in neuroblastoma due to its cytoplasmic sequestration. This thesis therefore has examined the functionality of p53 and its role in determining drug response of neuroblastoma cells. An initial study was undertaken that characterised an unusually broad multidrug resistance (MDR) phenotype of a neuroblastoma cell line (IMR/KAT100). The results demonstrated that the MDR phenotype of the IMR/KAT100 cells was associated with the acquisition of mutant p53. To explore the role of p53 in drug resistance further, p53-deficient variants in cell lines with wild-type p53 were generated by transduction of p53-suppressive constructs encoding either shRNA or a dominant-negative p53 mutant. Analysis of these cells indicated that: (i) in contrast to previous reports, wild-type p53 was fully functional in all neuroblastoma lines tested, as evidenced by its activation and nuclear translocation in response to DNA damage, transactivation of target genes and control of cell cycle checkpoints; (ii) inactivation of p53 in neuroblastoma cells resulted in establishment of an MDR phenotype; (iii) knockdown of mutant p53 did not revert the drug resistance phenotype, suggesting it is determined by loss of wild-type function rather than gain of mutant function; (iv) p53-dependent cell senescence, the primary response of S-type neuroblastoma cells to DNA damage, is replaced, after p53 inactivation, by mitotic catastrophe and subsequent apoptosis. In contrast to neuroblastoma, p53 suppression had no effect or increased drug susceptibility in several other tumour cell types, indicating the importance of tissue context for p53- mediated modulation of tumour cell sensitivity to treatment. Taken together, these data provide strong evidence for p53 having a role in mediating drug resistance in neuroblastoma and suggest that p53 status may be an important prognostic marker of treatment response in this disease.

Multidrug resistance phosphoglycoprotein (MDR1/P-gp) and breast cancer resistance protein (BCRP) were first isolated in chemoresistant cancer cells and have since been found in a variety of normal tissue, including the placenta. The potential function of MDR1/P-gp and BCRP in the human placenta is to protect the fetus from maternally circulating endogenous steroids and hormones, therapeutic drugs and toxins. The objective of this study was to examine the role of maternal steroids in the regulation of MDR1/P-gp and BCRP in the human placenta. Trophoblast cells were isolated from term placenta tissues and immunohistochemistry, western blot analysis and transport studies were used to determine the effect of maternal steroids on MDR1/P-gp and BCRP regulation. Maternal steroids, present at high concentrations in maternal serum, did not have an effect on BCRP in human syncytiotrophoblast. Estrogen and progesterone did not alter MDR1/P-gp levels in human syncytiotrophoblast, but cortisol significantly decreased MDR1/P-gp levels.

ABC drug transporter, MDR1, is a drug flippase that moves a variety of hydrophobic molecules from the inner to the outer leaflet of the plasma membrane. We have previously reported that MDR1 can function as a glycolipid flippase, being one of the mechanisms responsible for the translocation of glucosylceramide into the Golgi for neutral, but not acidic, glycosphingolipids (GSLs) synthesis. The interplay between GSLs and MDR1 could provide a whole new spectrum of innovative therapeutic options. We found that cell surface MDR1 partially co-localized with globotriaosyl ceramide (Gb3) in MDR1 transfected cells. Inhibition of GSL biosynthesis results in the loss of drug resistance and of cell surface MDR1. We speculated that an association of MDR1 and cell surface GSLs, in particular Gb3, may be functional at the cell surface, as MDR1 partitions into plasma membrane lipid rafts regulating MDR1 function. We therefore tested adamantyl Gb3 (adaGb3), a water soluble analog of Gb3, on MDR1 functions. AdaGb3 was able to inhibit MDR1-mediated rhodamine 123 drug efflux from MDR1 expressing cells, like cyclosporin A (CsA), a classical MDR1 inhibitor. AdaGb3 was also able to reverse vinblastine drug resistance in cell culture, whereas adamantyl galactosylceramide had no effect on drug resistance. The strong MDR1 reversal effects of adaGb3, as well as its favourable in vivo features make it a possible choice for inhibition of MDR1 to increase bioavailability of drugs across the intestinal epithelium (De Rosa et al., 2008). Thus, specific GSL analogs provide a new approach to MDR reversal. We have previously shown that MDR1 inhibitor CsA depletes Fabry cell lines of Gb3, the characteristic GSL accumulated in this disease, by preventing its de novo synthesis, and can also deplete Gaucher lymphoid cell lines of accumulated GlcCer (Mattocks et al., 2006). Liver and heart sections of Fabry mice treated with third generation MDR1 inhibitors showed significantly less Gb3 than liver and heart sections of untreated Fabry mice. Thus, MDR1 inhibition offers a potential alternative therapeutic approach not only for Fabry disease given the extraordinary cost of conventional enzyme replacement therapy, but also for other neutral GSL storage diseases, such as Gaucher disease.

ABC drug transporter, MDR1, is a drug flippase that moves a variety of hydrophobic molecules from the inner to the outer leaflet of the plasma membrane. We have previously reported that MDR1 can function as a glycolipid flippase, being one of the mechanisms responsible for the translocation of glucosylceramide into the Golgi for neutral, but not acidic, glycosphingolipids (GSLs) synthesis. The interplay between GSLs and MDR1 could provide a whole new spectrum of innovative therapeutic options. We found that cell surface MDR1 partially co-localized with globotriaosyl ceramide (Gb3) in MDR1 transfected cells. Inhibition of GSL biosynthesis results in the loss of drug resistance and of cell surface MDR1. We speculated that an association of MDR1 and cell surface GSLs, in particular Gb3, may be functional at the cell surface, as MDR1 partitions into plasma membrane lipid rafts regulating MDR1 function. We therefore tested adamantyl Gb3 (adaGb3), a water soluble analog of Gb3, on MDR1 functions. AdaGb3 was able to inhibit MDR1-mediated rhodamine 123 drug efflux from MDR1 expressing cells, like cyclosporin A (CsA), a classical MDR1 inhibitor. AdaGb3 was also able to reverse vinblastine drug resistance in cell culture, whereas adamantyl galactosylceramide had no effect on drug resistance. The strong MDR1 reversal effects of adaGb3, as well as its favourable in vivo features make it a possible choice for inhibition of MDR1 to increase bioavailability of drugs across the intestinal epithelium (De Rosa et al., 2008). Thus, specific GSL analogs provide a new approach to MDR reversal. We have previously shown that MDR1 inhibitor CsA depletes Fabry cell lines of Gb3, the characteristic GSL accumulated in this disease, by preventing its de novo synthesis, and can also deplete Gaucher lymphoid cell lines of accumulated GlcCer (Mattocks et al., 2006). Liver and heart sections of Fabry mice treated with third generation MDR1 inhibitors showed significantly less Gb3 than liver and heart sections of untreated Fabry mice. Thus, MDR1 inhibition offers a potential alternative therapeutic approach not only for Fabry disease given the extraordinary cost of conventional enzyme replacement therapy, but also for other neutral GSL storage diseases, such as Gaucher disease.

Multidrug resistance phosphoglycoprotein (MDR1/P-gp) and breast cancer resistance protein (BCRP) were first isolated in chemoresistant cancer cells and have since been found in a variety of normal tissue, including the placenta. The potential function of MDR1/P-gp and BCRP in the human placenta is to protect the fetus from maternally circulating endogenous steroids and hormones, therapeutic drugs and toxins. The objective of this study was to examine the role of maternal steroids in the regulation of MDR1/P-gp and BCRP in the human placenta. Trophoblast cells were isolated from term placenta tissues and immunohistochemistry, western blot analysis and transport studies were used to determine the effect of maternal steroids on MDR1/P-gp and BCRP regulation. Maternal steroids, present at high concentrations in maternal serum, did not have an effect on BCRP in human syncytiotrophoblast. Estrogen and progesterone did not alter MDR1/P-gp levels in human syncytiotrophoblast, but cortisol significantly decreased MDR1/P-gp levels.

<p>Many studies have reported low cure rates for multidrug-resistant tuberculosis (MDRTB) patients and MDR-TB patients co-infected with human immunodeficiency virus (HIV). However, little is&nbsp / known about the effect of HIV infection and antiretroviral therapy on the treatment outcomes of MDR-TB in South Africa. Therefore, the objectives of the study are: to find out whether HIV infection&nbsp / and interactions between ARVs and second line anti-TB drugs have an impact on the following MDR-TB treatment outcomes: cure rate and treatment failure at Brewelskloof Hospital. MDR-TB&nbsp / patients were treated for 18-24 months. The study was designed as a case-control retrospective study comparing MDR-TB treatment outcomes between HIV positive (cases) and HIV negative&nbsp / patients (controls). Patients were included in the study only if they complied with the following criteria: sensitivity to second line anti-TB drugs, MDR-TB infection, co-infection with HIV (for some&nbsp / of them), male and female patients, completion of treatment between 1 January 2006 and 31 December 2008. Any patients that presented with extreme drug-resistant tuberculosis (XDR-TB)&nbsp / were excluded from the study. Data were retrospectively collected from each patient&rsquo / s medical records. There were a total of 336 patients of which 242 (72%) were MDR-TB patients and 94&nbsp / (27.9%) MDRTB co-infected with HIV patients. Out of the 242 MDR-TB patients, 167 (69.2%) were males and 75 (30.7%) were females. Of the 94 patients with MDR-TB co-infected with HIV, 51&nbsp / (54.2%) males and 43 (45.7%) females. Patients with multidrug-resistant tuberculosis co-infected with HIV who qualify for antiretroviral therapy were treated with stavudine, lamivudine and&nbsp / efavirenz while all MDR-TB patients were given kanamycin, ethionamide, ofloxacin, cycloserine and pyrazinamide. The cure rate of MDR-TB in HIV (+) patients and in HIV (-) patients is 34.5%&nbsp / and 30 % respectively. There is no significant difference between both artes (pvalue = 0.80). The MDR-TB cure rate in HIV (+) patients taking antiretroviral drugs and in HIV (+) patients without&nbsp / antiretroviral therapy is 35% and 33% respectively. The difference between both rates is not statistically significant. The study shows that 65 (28.0%) patients completed MDR-TB treatment but&nbsp / could not be classified as cured or failure, 29 (12.5%) patients failed, 76 (32.7%) defaulted, 18 (7.7%) were transferred out and 44 (18.9%) died. As far as treatment completed and defaulted is concerned,&nbsp / there is no significant statistical difference between HIV (+) and HIV (-) The number of patients who failed the MDR-TB treatment and who were transferred out is significantly higher in the HIV (-)&nbsp / group than in the HIV (+) group. Finally the number of MDR-TB patients who died is significantly higher in the HIV (+) group). The median (range) duration of antiretroviral therapy before starting&nbsp / anti-tuberculosis drugs is 10.5 (1-60) months. According to this study results, the MDR-TB treatment cure rate at Brewelkloof hospital is similar to the cure rate at the national level. The study also&nbsp / hows that HIV infection and antiretroviral drugs do not influence any influence on MDR-TB treatment outcomes.</p>

In this study, mechanisms of resistance to Imatinib-induced apoptosis in human K562 and Meg-1 chronic myeloid leukemia (CML) cells were examined. Continuous exposure of cells to step-wise increasing concentrations of Imatinib resulted in the selection of 0.2 and 1 &amp / #956 / M imatinib resistant cells. Measurement of endogenous ceramide levels showed that treatment with Imatinib increased the generation of C18-ceramide significantly, which is mainly synthesized by the human longevity assurance gene 1 (hLASS1), in sensitive, but not in resistant cells. Mechanistically, analysis of mRNA and enzyme activity levels of hLASS1 in the absence or presence of Imatinib did not show any significant differences in the resistant cells when compared to its sensitive counterparts, suggesting that accumulation and/or metabolism, but not the synthesis of ceramide, might be altered in resistant cells. iv Indeed, further studies demonstrated that expression levels, and enzyme activity of sphingosine kinase-1 (SK-1), increased significantly in resistant K562 or Meg-1 cells. The expression levels of glucosyl ceramide synthase (GCS) also increased in resistant cells, comparing to the sensitive counterparts, which indicates conversion of pro-apoptotic ceramide to glucosyl ceramide. Expression analyses of BCR-ABL gene demonstrated that expression levels of BCR-ABL gene increased gradually as the cells acquired the resistance. However, Nucleotide sequence analyses of ABL kinase gene revealed that there was no mutation in Imatinib binding region of the gene in resistant cells. There was also an increase in expression levels of MDR1 gene in resistant cells, which transport the toxic substances outside of cells. In conclusion, these data show, for the first time, a role for endogenous ceramide synthesis via hLASS1 in Imatinib-induced apoptosis, and those alterations of the balance between the levels of ceramide and S1P. Mainly the overexpression of SK-1 seems to result in resistance to Imatinib in K562 cells. The cellular resistance may also result from conversion of ceramide to glucosyl ceramide, from overexpression of BCR-ABL and MDR1 genes but not due to mutations in Imatinib binding site of ABL kinase.