Prevalence of Escherichia coli O157:H7 in water and meat and meat products and vegetables sold in the Eastern Cape Province of South Africa and its impact on the diarrhoeic conditions of HIV/AIDS patients
- Authors: Abong'o, Benard Omondi
- Date: 2008
- Subjects: Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11263 , http://hdl.handle.net/10353/87 , Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Description: Water and food borne Escherichia coli O157:H7 could be one of the pathogens posing high health risk to patients suffering from Acquired Immunodeficiency Syndrome (AIDS) because of its incrimination in diarrhoea cases in AIDS patients. The present study, which was conducted between March 2005 and August 2006, investigated the prevalence of E. coli O157:H7 in water, meat and meat products and vegetables and its impact on diarrhoeic conditions of confirmed and non-confirmed HIV/AIDS patients in the Amathole District in the Eastern Cape Province of South Africa. The water samples used in the study were obtained from stand pipes supplying treated drinking water to communities residing in Fort Beaufort, Alice, Dimbaza and Mdantsane whereas borehole waters were sampled from Ngwenya and Kwasaki. The meat and meat products and vegetable samples were purchased from shops, butcheries, supermarkets and open air markets in Fort Beaufort, Alice and Mdantsane. The stool swabs used in the study were obtained from HIV/AIDS and outpatient clinics at Frere Hospital in East London. A total of 180 each of water, meat and meat products and vegetable samples and another 360 stool samples were analyzed for E. coli O157:H7. Presumptive E. coli O157 was isolated from the samples by culture-based methods and confirmed using Polymerase Chain Reaction techniques. Anti-biogram as well as risk assessment were also carried out using standard methods. The viable counts of presumptive E. coli O157 for water samples ranged between 3.3 × 104 and 1.71 × 105 CFU/ml, and between 1.8 × 104 and 5.04 × 106 CFU/g for meat and meat products, whereas those for vegetables ranged between 1.3 × 103 and 1.6 × 106 CFU/g. The counts of presumptive E. coli O157 for the water and vegetable samples were not significantly different whereas those for meat and meat products were found to be significantly different (P ≤ 0.05). The prevalence rates of presumptive E coli O157 in meat and meat products was 35.55 percent (64/180), and 25.55 percent (46/180) and 21.66 percent (39/180) for water and vegetables respectively. Prevalence of presumptive E. coli O157 in the stool samples of HIV/AIDS patients was 36.39 percent (131/360), of which 56.5 percent (74/131) and 43.5 percent (57/131) were from stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Molecular analysis of representative presumptive E. coli O157 indicated that 10.29 percent (4/39) of vegetables; 14.81 percent (4/27) of water and 38.46 percent (5/13) of meat and meat products carried E. coli O157:H7. Also 36 percent (9/25) and 17.24 percent (5/29) of the stool samples were positive for E. coli O157:H7. Antimicrobial susceptibility profile revealed that all of the E. coli O157:H7 isolated from water, meat and meat products and vegetables as well as those isolated from stools of confirmed and non-confirmed HIV/AIDS patients were resistant (R) to gentamycin and erythromycin. However, 75 percent (20/27) of these isolates were resistant (R) to ampicillin and tetracycline whereas approximately 25 percent (6/27) were resistant (R) to nalidixic acid, ceftriaxone, and chloramphenicol. All the isolates (27/27) were susceptible (S) to amikacin. Probability of risk of E. coli O157:H7 infection was high for confirmed HIV/AIDS patients than for the non-confirmed HIV/AIDS patients. Estimated probability of risk of E. coli O157:H7 due to ingestion of water was 1.00 for 100 confirmed and non-confirmed HIV/AIDS patients. Risk due to meat and meat products was estimated at 0.27 and 0.20 and for vegetables at 0.21 and 0.15 per 100 confirmed and non-confirmed HIV/AIDS patients. The findings of this study predicted a possible link between E. coli O157:H7 isolated from drinking water, meat and meat products and vegetables and diarrhoeic conditions in both confirmed and non-confirmed HIV/AIDS patients, and concludes that confirmed HIV/AIDS patients can be at higher risk of contracting water and food borne E. coli O157:H7 than nonconfirmed HIV/AIDS patients. It is thus recommended that proper water treatment and food handling, maximum food and water safety and sanitation as well as personal body hygiene should be maintained, in order to prevent E. coli O157:H7 infections. Education initiatives and active surveillance of E. coli O157:H7 should be taken by all the stake-holders working directly or indirectly towards ensuring enduring sound public health.
- Full Text:
- Date Issued: 2008
- Authors: Abong'o, Benard Omondi
- Date: 2008
- Subjects: Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11263 , http://hdl.handle.net/10353/87 , Foodborne diseases , Diarrhea , Escherichia coli , HIV infections , AIDS (Disease) , Bacterial diseases
- Description: Water and food borne Escherichia coli O157:H7 could be one of the pathogens posing high health risk to patients suffering from Acquired Immunodeficiency Syndrome (AIDS) because of its incrimination in diarrhoea cases in AIDS patients. The present study, which was conducted between March 2005 and August 2006, investigated the prevalence of E. coli O157:H7 in water, meat and meat products and vegetables and its impact on diarrhoeic conditions of confirmed and non-confirmed HIV/AIDS patients in the Amathole District in the Eastern Cape Province of South Africa. The water samples used in the study were obtained from stand pipes supplying treated drinking water to communities residing in Fort Beaufort, Alice, Dimbaza and Mdantsane whereas borehole waters were sampled from Ngwenya and Kwasaki. The meat and meat products and vegetable samples were purchased from shops, butcheries, supermarkets and open air markets in Fort Beaufort, Alice and Mdantsane. The stool swabs used in the study were obtained from HIV/AIDS and outpatient clinics at Frere Hospital in East London. A total of 180 each of water, meat and meat products and vegetable samples and another 360 stool samples were analyzed for E. coli O157:H7. Presumptive E. coli O157 was isolated from the samples by culture-based methods and confirmed using Polymerase Chain Reaction techniques. Anti-biogram as well as risk assessment were also carried out using standard methods. The viable counts of presumptive E. coli O157 for water samples ranged between 3.3 × 104 and 1.71 × 105 CFU/ml, and between 1.8 × 104 and 5.04 × 106 CFU/g for meat and meat products, whereas those for vegetables ranged between 1.3 × 103 and 1.6 × 106 CFU/g. The counts of presumptive E. coli O157 for the water and vegetable samples were not significantly different whereas those for meat and meat products were found to be significantly different (P ≤ 0.05). The prevalence rates of presumptive E coli O157 in meat and meat products was 35.55 percent (64/180), and 25.55 percent (46/180) and 21.66 percent (39/180) for water and vegetables respectively. Prevalence of presumptive E. coli O157 in the stool samples of HIV/AIDS patients was 36.39 percent (131/360), of which 56.5 percent (74/131) and 43.5 percent (57/131) were from stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Molecular analysis of representative presumptive E. coli O157 indicated that 10.29 percent (4/39) of vegetables; 14.81 percent (4/27) of water and 38.46 percent (5/13) of meat and meat products carried E. coli O157:H7. Also 36 percent (9/25) and 17.24 percent (5/29) of the stool samples were positive for E. coli O157:H7. Antimicrobial susceptibility profile revealed that all of the E. coli O157:H7 isolated from water, meat and meat products and vegetables as well as those isolated from stools of confirmed and non-confirmed HIV/AIDS patients were resistant (R) to gentamycin and erythromycin. However, 75 percent (20/27) of these isolates were resistant (R) to ampicillin and tetracycline whereas approximately 25 percent (6/27) were resistant (R) to nalidixic acid, ceftriaxone, and chloramphenicol. All the isolates (27/27) were susceptible (S) to amikacin. Probability of risk of E. coli O157:H7 infection was high for confirmed HIV/AIDS patients than for the non-confirmed HIV/AIDS patients. Estimated probability of risk of E. coli O157:H7 due to ingestion of water was 1.00 for 100 confirmed and non-confirmed HIV/AIDS patients. Risk due to meat and meat products was estimated at 0.27 and 0.20 and for vegetables at 0.21 and 0.15 per 100 confirmed and non-confirmed HIV/AIDS patients. The findings of this study predicted a possible link between E. coli O157:H7 isolated from drinking water, meat and meat products and vegetables and diarrhoeic conditions in both confirmed and non-confirmed HIV/AIDS patients, and concludes that confirmed HIV/AIDS patients can be at higher risk of contracting water and food borne E. coli O157:H7 than nonconfirmed HIV/AIDS patients. It is thus recommended that proper water treatment and food handling, maximum food and water safety and sanitation as well as personal body hygiene should be maintained, in order to prevent E. coli O157:H7 infections. Education initiatives and active surveillance of E. coli O157:H7 should be taken by all the stake-holders working directly or indirectly towards ensuring enduring sound public health.
- Full Text:
- Date Issued: 2008
The development, implementation and evaluation of a locus of control-based training programme for HIV and AIDS risk reduction among university students
- Authors: Gwandure, Calvin
- Date: 2009
- Subjects: AIDS (Disease) -- Prevention , HIV infections , Universities and colleges -- Health promotion services , Risk communication -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9838 , http://hdl.handle.net/10948/1242 , AIDS (Disease) -- Prevention , HIV infections , Universities and colleges -- Health promotion services , Risk communication -- South Africa
- Description: There is an escalation of HIV and AIDS among the youth in South Africa and other developing countries. Research on HIV and AIDS risk factors has tended to focus more on poverty, gender, race, illiteracy, and violence than personality factors that could influence an individual` s health-protective behaviour. Previous studies have also shown that wealth, education, race, and gender may not make an individual more or less vulnerable to HIV infection. This study argued that locus of control could influence an individual` s health-protective behaviour and that external locus of control could be a risk factor in HIV and AIDS risk reduction. The aim of this study was to investigate the efficacy of a locus of control-based training programme in reducing HIV and AIDS risk among university students. The locus of control-based variables that formed the training programme for HIV and AIDS risk reduction among university students were: social systems control, self-control, fatalism, achievement-oriented behaviour, deferment of gratification, personal values and expectancies, and social alienation. These locus of control-based variables were regarded as contexts in which individuals could exhibit health risk behaviours. A sample of 257 first-year university students participated in the study. There were (N = 170) female participants and (N = 87) male participants drawn from the University of the Witwatersrand. The study was a pretest-posttest repeated measures design. Data were analysed using t tests, correlations, multiple regression, structural equation modelling, and repeated measures tests. The results of this study showed significant differences in health risks between participants with an external locus of control and participants with an internal locus of control. There was a significant relationship between locus of control-based variables and HIV and AIDS risk. The locus of control-based training programme significantly modified personality and significantly reduced locus of control-based health risks and HIV and AIDS risk. Directions for future research on locus of control, health risks, and HIV and AIDS risk could focus on the development and implementation of various locus of control-based training programmes in South Africa. Locus of control should be targeted as a health risk factor in HIV and AIDS risk reduction training programmes.
- Full Text:
- Date Issued: 2009
- Authors: Gwandure, Calvin
- Date: 2009
- Subjects: AIDS (Disease) -- Prevention , HIV infections , Universities and colleges -- Health promotion services , Risk communication -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9838 , http://hdl.handle.net/10948/1242 , AIDS (Disease) -- Prevention , HIV infections , Universities and colleges -- Health promotion services , Risk communication -- South Africa
- Description: There is an escalation of HIV and AIDS among the youth in South Africa and other developing countries. Research on HIV and AIDS risk factors has tended to focus more on poverty, gender, race, illiteracy, and violence than personality factors that could influence an individual` s health-protective behaviour. Previous studies have also shown that wealth, education, race, and gender may not make an individual more or less vulnerable to HIV infection. This study argued that locus of control could influence an individual` s health-protective behaviour and that external locus of control could be a risk factor in HIV and AIDS risk reduction. The aim of this study was to investigate the efficacy of a locus of control-based training programme in reducing HIV and AIDS risk among university students. The locus of control-based variables that formed the training programme for HIV and AIDS risk reduction among university students were: social systems control, self-control, fatalism, achievement-oriented behaviour, deferment of gratification, personal values and expectancies, and social alienation. These locus of control-based variables were regarded as contexts in which individuals could exhibit health risk behaviours. A sample of 257 first-year university students participated in the study. There were (N = 170) female participants and (N = 87) male participants drawn from the University of the Witwatersrand. The study was a pretest-posttest repeated measures design. Data were analysed using t tests, correlations, multiple regression, structural equation modelling, and repeated measures tests. The results of this study showed significant differences in health risks between participants with an external locus of control and participants with an internal locus of control. There was a significant relationship between locus of control-based variables and HIV and AIDS risk. The locus of control-based training programme significantly modified personality and significantly reduced locus of control-based health risks and HIV and AIDS risk. Directions for future research on locus of control, health risks, and HIV and AIDS risk could focus on the development and implementation of various locus of control-based training programmes in South Africa. Locus of control should be targeted as a health risk factor in HIV and AIDS risk reduction training programmes.
- Full Text:
- Date Issued: 2009
Indian secondary school youths' understanding of sexual violence in their community in the age of HIV and AIDS: a participatory video approach
- Authors: Mahadev, Rekha
- Date: 2014
- Subjects: Sex crimes , Indian youth -- Education (Secondary) , AIDS (Disease) , HIV infections
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/7522 , vital:21793
- Description: This study focuses on Indian secondary school youths’ understanding of sexual violence in their community in the age of HIV and AIDS, and the contribution that participatory video can make to address sexual violence. South Africa, apart from having the highest HIV prevalence in the world, also has the highest incidence of sexual violence. South African society often appears complacent about the high levels of sexual violence. In the Indian community, especially among the youth, sexual violence is also cause for concern. Much effort and energy has been expended in educating learners about sexual violence and HIV and AIDS with the objective of raising awareness of the dangers of engaging in risky sexual behaviour, and ultimately to empower and influence positive behaviour change. Because HIV prevalence in the Indian population is on the rise, Indian youth’s particular vulnerability is the reason for focusing on how they understand sexual violence in the age of AIDS. Besides the paucity of research on Indian youth and sexual violence, the methodologies which have been used produced research which is descriptive in nature and hence a methodological shift from traditional methodologies to a participatory visual methodology which has the potential for critically engaging the Indian youth on the issues of sexual violence, could contribute to research which has a social change focus. This qualitative research therefore uses a visual participatory methodology within a critical research paradigm, to explore and contribute to addressing the problem of sexual violence in the age of HIV and AIDS. The participants in the study, a sample of 20 Indian learners (10 boys and 10 girls), from a secondary school in Durban which has predominantly Indian learners, was purposively selected from Grade 11 classes. Participatory video enabled them to voice how they understand sexual violence and in doing so move towards reflecting on their own agency. The theory of triadic influence with its three streams, i.e. cultural attitudinal, social normative and intrapersonal, was used to make meaning of the findings. It also provided a frame for a fourth path, namely the preventive intervene. While participatory video enabled exploring Indian youths’ understanding of sexual violence in their community in the age of AIDS, it at the same time enabled them to reflect on, and perhaps begin to disrupt their understanding of the cultural attitudinal, social normative and the intrapersonal influences and how these influence their thinking about sexual violence. Two a priori themes were established prior to the analysis, to respond to how Indian youths understand sexual violence in the age of AIDS, and how participatory video can address sexual violence. The findings suggest that their understanding of sexual violence stems from a culture of concealment in which veiling sexual violence is the norm; that the vulnerability of youth increases as the experience of pressure from peers to engage in sexual violence increases; and that sexual violence is traumatising. The use of participatory video increased the youths’ reflexivity and created a space for them to explore how to take action. The findings imply that addressing sexual violence with Indian youth should begin with interrogating the cultural norms of masculinities and femininities, and the cultural practices rooted in traditional structures of the family and community which perpetuate gender disparities and the restriction of the autonomy of women and girls. Addressing issues of vulnerability and sexual violence should be the focus of all school and community interventions to ensure learners’ well-being and ability to resist negative peer pressure. These interventions should encourage self-reflection and raise social awareness through active participation and in so doing bring about social change in the Indian community. Vigorous participatory interventions which draw on the voices of the Indian youth as agents of social change in addressing sexual violence in the age of HIV and AIDS, is therefore urgent. The significance of this study as research as intervention is useful in enabling the exploration - with the Indian youth - of how cultural and religious norms, gender disparity, Indian masculinities and femininities, and social peer pressure feed into youth’s understanding of sexual violence and at the same time getting them to begin rethinking, challenging and disrupting these understandings where necessary. The study demonstrates that engaging youth affords them an opportunity to draw from their own experiences and through their own voices and actions create knowledge through participatory video, thereby making a contribution to visual methodologies and research around sexual violence and HIV and AIDS in their world.
- Full Text:
- Date Issued: 2014
- Authors: Mahadev, Rekha
- Date: 2014
- Subjects: Sex crimes , Indian youth -- Education (Secondary) , AIDS (Disease) , HIV infections
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/7522 , vital:21793
- Description: This study focuses on Indian secondary school youths’ understanding of sexual violence in their community in the age of HIV and AIDS, and the contribution that participatory video can make to address sexual violence. South Africa, apart from having the highest HIV prevalence in the world, also has the highest incidence of sexual violence. South African society often appears complacent about the high levels of sexual violence. In the Indian community, especially among the youth, sexual violence is also cause for concern. Much effort and energy has been expended in educating learners about sexual violence and HIV and AIDS with the objective of raising awareness of the dangers of engaging in risky sexual behaviour, and ultimately to empower and influence positive behaviour change. Because HIV prevalence in the Indian population is on the rise, Indian youth’s particular vulnerability is the reason for focusing on how they understand sexual violence in the age of AIDS. Besides the paucity of research on Indian youth and sexual violence, the methodologies which have been used produced research which is descriptive in nature and hence a methodological shift from traditional methodologies to a participatory visual methodology which has the potential for critically engaging the Indian youth on the issues of sexual violence, could contribute to research which has a social change focus. This qualitative research therefore uses a visual participatory methodology within a critical research paradigm, to explore and contribute to addressing the problem of sexual violence in the age of HIV and AIDS. The participants in the study, a sample of 20 Indian learners (10 boys and 10 girls), from a secondary school in Durban which has predominantly Indian learners, was purposively selected from Grade 11 classes. Participatory video enabled them to voice how they understand sexual violence and in doing so move towards reflecting on their own agency. The theory of triadic influence with its three streams, i.e. cultural attitudinal, social normative and intrapersonal, was used to make meaning of the findings. It also provided a frame for a fourth path, namely the preventive intervene. While participatory video enabled exploring Indian youths’ understanding of sexual violence in their community in the age of AIDS, it at the same time enabled them to reflect on, and perhaps begin to disrupt their understanding of the cultural attitudinal, social normative and the intrapersonal influences and how these influence their thinking about sexual violence. Two a priori themes were established prior to the analysis, to respond to how Indian youths understand sexual violence in the age of AIDS, and how participatory video can address sexual violence. The findings suggest that their understanding of sexual violence stems from a culture of concealment in which veiling sexual violence is the norm; that the vulnerability of youth increases as the experience of pressure from peers to engage in sexual violence increases; and that sexual violence is traumatising. The use of participatory video increased the youths’ reflexivity and created a space for them to explore how to take action. The findings imply that addressing sexual violence with Indian youth should begin with interrogating the cultural norms of masculinities and femininities, and the cultural practices rooted in traditional structures of the family and community which perpetuate gender disparities and the restriction of the autonomy of women and girls. Addressing issues of vulnerability and sexual violence should be the focus of all school and community interventions to ensure learners’ well-being and ability to resist negative peer pressure. These interventions should encourage self-reflection and raise social awareness through active participation and in so doing bring about social change in the Indian community. Vigorous participatory interventions which draw on the voices of the Indian youth as agents of social change in addressing sexual violence in the age of HIV and AIDS, is therefore urgent. The significance of this study as research as intervention is useful in enabling the exploration - with the Indian youth - of how cultural and religious norms, gender disparity, Indian masculinities and femininities, and social peer pressure feed into youth’s understanding of sexual violence and at the same time getting them to begin rethinking, challenging and disrupting these understandings where necessary. The study demonstrates that engaging youth affords them an opportunity to draw from their own experiences and through their own voices and actions create knowledge through participatory video, thereby making a contribution to visual methodologies and research around sexual violence and HIV and AIDS in their world.
- Full Text:
- Date Issued: 2014
Studies directed towards the synthesis of chromone carbaldehyde-derived HIV-1 protease inhibitors
- Authors: Molefe, Duduzile Mabel
- Date: 2008
- Subjects: Protease Inhibitors , HIV infections , HIV (Viruses) , AIDS (Disease) , Proteolytic enzymes , Heterocyclic compounds -- Derivatives , Chemical kinetics , Nuclear magnetic resonance spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4526 , http://hdl.handle.net/10962/d1015542
- Description: A series of chromone-3-carbaldehydes have been prepared using Vilsmeier-Haack methodology while a corresponding series of chromone-2-carbaldeydes have been synthesized via the Kostanecki-Robinson reaction. Baylis-Hillman reactions have been conducted on both series of chromone carbaldehydes using three different catalysts, viz., 1,4-diazabicyclo(2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec- 7-ene (DBU) and 3-hydroxyquinuclidine (3HQ), and acrylonitrile, methyl acrylate and methyl vinyl ketone as the activated alkenes. These reactions have typically (but not always!) afforded both normal Baylis-Hillman and dimeric products. Attention has also been given to the use of 1-methyl-2-pyrrolidine (1-NMP), an ionic liquid, to replace normal organic solvents, and it has been found that, in the presence of DABCO, chromone-3-carbaldehydes afford the dimeric products alone. Reactions of chromone-3-carbaldehydes with methyl vinyl ketone have yielded unexpected, novel adducts, which appear to arise from preferential attack at C(2) in the chromone nucleus. Research on chromone-2-carbaldeydes under Baylis-Hillman conditions has also resulted in the formation of some interesting products instead of the expected Baylis-Hillman adducts. The Baylis-Hillman products have been explored as substrates for aza-Michael reactions using various amino derivatives including protected amino acids in the presence of the tetrabutylammonium bromide (TBAB) and the ionic liquid, 3-butyl-1- methylimidazoleboranetetrafluoride (BmimBF₄), as catalysts. The aza-Michael products have been targeted as truncated ritonavir analogues for investigation as potential HIV -1 protease inhibitors, and representative compounds have been subjected to enzyme inhibition assays to explore the extent and type of inhibition. Lineweaver-Burk and Dixon plots have indicated competitive inhibition in one case as well as non-competitive inhibition in another, and the inhibition constants (Ki) have been compared with that of the ritonavir. Computer modelling studies have also been conducted on selected chromonecontaining derivatives, using the ACCELRYS Cerius² platform. Interactive docking of the chromone-containing ligands into the HIV -1 protease receptor site, using the Ligandfit module, has indicated the importance of hydrogen-bonding interactions mediated by bridging water molecules situated in the receptor cavity. NMR spectroscopy has been used to elucidate complex and competing mechanistic pathways involved in the Baylis-Hillman reactions of selected 2-nitrobenzaldehydes with MVK in the presence of DABCO - reactions which afford the normal BaylisHillman product, the MVK dimer and syn- and anti-Baylis-Hillman type diadducts. The kinetic data confirm the concomitant operation of two pathways and reveal that, in the initial stage of the reaction, the product distribution is kinetically controlled, whereas in the latter stage, thermodynamic control results in the consumption of the normal Baylis-Hillman product and predominance of the anti-diadduct.
- Full Text:
- Date Issued: 2008
- Authors: Molefe, Duduzile Mabel
- Date: 2008
- Subjects: Protease Inhibitors , HIV infections , HIV (Viruses) , AIDS (Disease) , Proteolytic enzymes , Heterocyclic compounds -- Derivatives , Chemical kinetics , Nuclear magnetic resonance spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4526 , http://hdl.handle.net/10962/d1015542
- Description: A series of chromone-3-carbaldehydes have been prepared using Vilsmeier-Haack methodology while a corresponding series of chromone-2-carbaldeydes have been synthesized via the Kostanecki-Robinson reaction. Baylis-Hillman reactions have been conducted on both series of chromone carbaldehydes using three different catalysts, viz., 1,4-diazabicyclo(2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec- 7-ene (DBU) and 3-hydroxyquinuclidine (3HQ), and acrylonitrile, methyl acrylate and methyl vinyl ketone as the activated alkenes. These reactions have typically (but not always!) afforded both normal Baylis-Hillman and dimeric products. Attention has also been given to the use of 1-methyl-2-pyrrolidine (1-NMP), an ionic liquid, to replace normal organic solvents, and it has been found that, in the presence of DABCO, chromone-3-carbaldehydes afford the dimeric products alone. Reactions of chromone-3-carbaldehydes with methyl vinyl ketone have yielded unexpected, novel adducts, which appear to arise from preferential attack at C(2) in the chromone nucleus. Research on chromone-2-carbaldeydes under Baylis-Hillman conditions has also resulted in the formation of some interesting products instead of the expected Baylis-Hillman adducts. The Baylis-Hillman products have been explored as substrates for aza-Michael reactions using various amino derivatives including protected amino acids in the presence of the tetrabutylammonium bromide (TBAB) and the ionic liquid, 3-butyl-1- methylimidazoleboranetetrafluoride (BmimBF₄), as catalysts. The aza-Michael products have been targeted as truncated ritonavir analogues for investigation as potential HIV -1 protease inhibitors, and representative compounds have been subjected to enzyme inhibition assays to explore the extent and type of inhibition. Lineweaver-Burk and Dixon plots have indicated competitive inhibition in one case as well as non-competitive inhibition in another, and the inhibition constants (Ki) have been compared with that of the ritonavir. Computer modelling studies have also been conducted on selected chromonecontaining derivatives, using the ACCELRYS Cerius² platform. Interactive docking of the chromone-containing ligands into the HIV -1 protease receptor site, using the Ligandfit module, has indicated the importance of hydrogen-bonding interactions mediated by bridging water molecules situated in the receptor cavity. NMR spectroscopy has been used to elucidate complex and competing mechanistic pathways involved in the Baylis-Hillman reactions of selected 2-nitrobenzaldehydes with MVK in the presence of DABCO - reactions which afford the normal BaylisHillman product, the MVK dimer and syn- and anti-Baylis-Hillman type diadducts. The kinetic data confirm the concomitant operation of two pathways and reveal that, in the initial stage of the reaction, the product distribution is kinetically controlled, whereas in the latter stage, thermodynamic control results in the consumption of the normal Baylis-Hillman product and predominance of the anti-diadduct.
- Full Text:
- Date Issued: 2008
Exploring ways of assisting Lesotho educators to offer care and support to children orphaned and rendered vulnerable by HIV and AIDS
- Authors: Ntaote, Grace Makeletso
- Date: 2011
- Subjects: Orphans -- Developing Countries -- Social conditions , HIV infections
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9503 , http://hdl.handle.net/10948/1320 , Orphans -- Developing Countries -- Social conditions , HIV infections
- Description: The HIV and AIDS pandemic has resulted in 14 million children being orphaned worldwide. In Lesotho alone, where this study was carried out, there are about 180 000 of these children (UNAIDS, 2007). Teachers, especially in Lesotho‘s primary schools need to be equipped to better deal with the challenges that result from having these children in their classrooms. At the Lesotho College of Education, where I have worked for 12 years as a teacher educator, pre-service and in-service student teachers are not trained to offer care and support to orphans and vulnerable children. They experience problems in the classroom emanating from the needs of these children. This study followed an action research design to find ways to support teachers to better deal with the issues they face as a result of having orphans and vulnerable children in their classes. Using a qualitative approach, educators perceptions, feelings, attitudes and experiences in dealing with orphans and vulnerable children in their schools were identified, and it became apparent that educators were negatively affected on a personal and professional level. It was concluded that the development of resilience in educators would help them to better cope with orphans and vulnerable children in their classes. The chosen intervention Resilient Educators Programme (REds) was implemented and evaluated and findings revealed that it was beneficial in increasing educator resilience. Recommendations, based on the findings of the study, were made for future teacher education in this area.
- Full Text:
- Date Issued: 2011
- Authors: Ntaote, Grace Makeletso
- Date: 2011
- Subjects: Orphans -- Developing Countries -- Social conditions , HIV infections
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9503 , http://hdl.handle.net/10948/1320 , Orphans -- Developing Countries -- Social conditions , HIV infections
- Description: The HIV and AIDS pandemic has resulted in 14 million children being orphaned worldwide. In Lesotho alone, where this study was carried out, there are about 180 000 of these children (UNAIDS, 2007). Teachers, especially in Lesotho‘s primary schools need to be equipped to better deal with the challenges that result from having these children in their classrooms. At the Lesotho College of Education, where I have worked for 12 years as a teacher educator, pre-service and in-service student teachers are not trained to offer care and support to orphans and vulnerable children. They experience problems in the classroom emanating from the needs of these children. This study followed an action research design to find ways to support teachers to better deal with the issues they face as a result of having orphans and vulnerable children in their classes. Using a qualitative approach, educators perceptions, feelings, attitudes and experiences in dealing with orphans and vulnerable children in their schools were identified, and it became apparent that educators were negatively affected on a personal and professional level. It was concluded that the development of resilience in educators would help them to better cope with orphans and vulnerable children in their classes. The chosen intervention Resilient Educators Programme (REds) was implemented and evaluated and findings revealed that it was beneficial in increasing educator resilience. Recommendations, based on the findings of the study, were made for future teacher education in this area.
- Full Text:
- Date Issued: 2011
Genetic characteristics of Human Immunodeficiency Virus-1, and deter-minants of late presentation for care and Diabetes mellitus amongst newly diagnosed Human Immunodeficiency Virus positive patients in the Eastern Cape, South Africa.
- Authors: Sogbanmu, Olufunso Oladipo
- Date: 2019
- Subjects: HIV infections
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/${Handle} , vital:40495
- Description: Phylogenies may help to characterize transmission pairs, enhance contact tracing and outbreak investigations, track the origin and spread of epidemics over place and time, and to identify patterns of onward Human Immunodeficiency-Virus (HIV) transmission among risk groups. If the pattern and evolution of HIV drug resistance can be mapped, this may influence the development of guidelines in the clinical management of HIV especially with issues relating to prevalence of primary drug resistance and its impact on outcomes of present antiretroviral treatment (ART) regimen in use and the ability to trace and track the development of drug resistant strains. The roll-out of the test and treat Programme for newly diagnosed HIV infected pa-tient, seeks to identify HIV infected individuals early and to prevent morbidity and mortality associated with the late presentation for HIV care. The determination of the magnitude of ‘late presentation’ and or ‘presentation with advanced HIV disease’ can be used in very diverse settings and for many purposes. It provides a unified way to define the problem, thereby targeting appropriate interventions to prevent the detrimental outcomes associated with late presentation to care. The subtle relationship between HIV and diabetes mellitus (DM) may also help in formulating better preventive programs to aid the control of non-communicable diseases such as DM. This cross-sectional study includes a purposive selection of 335 HIV positive patients attending the voluntary counselling and Testing (VCT) and HIV Counselling and Testing (HCT) centres and outpatient departments at Cecilia Makiwane Hospital and the HCT sites at the Buffalo District municipality community health centres, Eastern Cape Province, South Africa. Late or delayed presentation of HIV infection was defined as CD4 cell count beneath 350 cells/μL and/or patients presenting with an AIDS-defining event at the first follow-up regardless of the CD4 cell count. Chapter 1 provides the general introduction had an overview of the introduction to the study, the statement of the research problem, hypothesis, the aim and the objectives. xx Chapter 2 looked in-depth at the HIV, case definition, the latest epidemiology of HIV, the HIV genome, the life cycle of HIV, its diagnosis, the classes of antiretroviral drugs, development of drug resistance. Chapter 3 highlighted the prevalence of Transmitted Drug Resistance (TDR) with focus on the protease gene. RNA was extracted from blood samples of 72 newly diagnosed HIV-1 patients attending some HIV testing and counselling clinics from August 2016 to July 2017. Protease fragments were amplified with specific primers by RT-PCR followed by nested PCR. The amplified products were sequenced using the ABI 360 sequencer, edited with Geneious version 9.1.5 and translated into amino acid with BioEdit software. Drug related resistance mutation (DRMs) analysis was performed on all the protease sequences in accordance with the 2009 WHO list of surveillance drug resistance mutations by submitting the edited sequences to Stanford HIV drug interpretation programme and the international AIDS society-USA guidelines for query of drug resistance associated mutations while phylogenetic analysis was performed using MEGA 6 to allocate all viral sequences into subtypes. In the study, a total of 52/72 (71.1%) reliable HIV-1 protease sequences were obtained in which subtyping and drug resistance mutations were performed. Two (3.8%) major Protease resistance associated mutation (V82A/L and L90M) were observed while another polymorphism like L10F, T74S, Q58E, L10I/V and M46V were also identified. Phylogenetic analyses delineated all the sequences as HIV-1 subtype C. Chapter 4 describes the prevalence and the determinants of late presentation amongst newly diagnosed HIV positive individuals in the Eastern Cape. It indicates the extent of the prevalence of patients presenting to care and at what HIV stage they were assessing health care services since the inception of the ‘test and treat’ strategy. It is a cross-sectional study where a total of 335 newly diagnosed patients were recruited consecutively be-tween August 2016 and July 2017. Late presenter for HIV care was defined in accordance with the European Late Presenter Consensus working group as a patient who reports for care when the CD4 count is below 350 cells/μL and/or when there is an established Aids- xxi defining clinical condition, irrespective of CD4 count. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of late HIV diagnosis. The study showed that 60% of patients were late presenters, with 35% presenting with advanced disease. The major determinants identified were being male and low level of education. This led to recommendations directed at ensuring programmes that targets men in identifying their HIV status and assess care at early stage to prevents the morbidity and mortality associated with delayed presentation. Also, it was recommended that effort should be made to improve access to education and also include HIV related topics into the educational curriculum. Chapter 5 aimed to describe the prevalence and determinants of DM amongst newly diagnosed HIV positive individuals. This is a cross-sectional study which recruited 335 patients between August 2016 and September 2017. Definition for diabetes mellitus was made based on the SEDMSA 2015 guideline of HBA1C of above 6.5%. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of abnormal glycated haemoglobin. Findings showed the prevalence of DM at about 6% amongst newly diagnosed HIV positive individuals. This is similar to findings in other study within the country, but a bit lower than what was obtained in the developed countries. The role of older age (above 40 years) as predisposing factor to development of diabetes in newly diagnosed HIV positive individual was well noted and taken. This ensures that screening for DM should be targeted at elderly HIV positive individuals. The grey area of the appropriate mode of diagnostic test to use to diagnose HIV is still debatable, however, a combination of HBA1c and fasting blood sugar (FBS) may improve the diagnosis of DM in this population group. In chapter 6, the general conclusions, recommendations and future perspectives of the study are reflected.
- Full Text:
- Date Issued: 2019
- Authors: Sogbanmu, Olufunso Oladipo
- Date: 2019
- Subjects: HIV infections
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/${Handle} , vital:40495
- Description: Phylogenies may help to characterize transmission pairs, enhance contact tracing and outbreak investigations, track the origin and spread of epidemics over place and time, and to identify patterns of onward Human Immunodeficiency-Virus (HIV) transmission among risk groups. If the pattern and evolution of HIV drug resistance can be mapped, this may influence the development of guidelines in the clinical management of HIV especially with issues relating to prevalence of primary drug resistance and its impact on outcomes of present antiretroviral treatment (ART) regimen in use and the ability to trace and track the development of drug resistant strains. The roll-out of the test and treat Programme for newly diagnosed HIV infected pa-tient, seeks to identify HIV infected individuals early and to prevent morbidity and mortality associated with the late presentation for HIV care. The determination of the magnitude of ‘late presentation’ and or ‘presentation with advanced HIV disease’ can be used in very diverse settings and for many purposes. It provides a unified way to define the problem, thereby targeting appropriate interventions to prevent the detrimental outcomes associated with late presentation to care. The subtle relationship between HIV and diabetes mellitus (DM) may also help in formulating better preventive programs to aid the control of non-communicable diseases such as DM. This cross-sectional study includes a purposive selection of 335 HIV positive patients attending the voluntary counselling and Testing (VCT) and HIV Counselling and Testing (HCT) centres and outpatient departments at Cecilia Makiwane Hospital and the HCT sites at the Buffalo District municipality community health centres, Eastern Cape Province, South Africa. Late or delayed presentation of HIV infection was defined as CD4 cell count beneath 350 cells/μL and/or patients presenting with an AIDS-defining event at the first follow-up regardless of the CD4 cell count. Chapter 1 provides the general introduction had an overview of the introduction to the study, the statement of the research problem, hypothesis, the aim and the objectives. xx Chapter 2 looked in-depth at the HIV, case definition, the latest epidemiology of HIV, the HIV genome, the life cycle of HIV, its diagnosis, the classes of antiretroviral drugs, development of drug resistance. Chapter 3 highlighted the prevalence of Transmitted Drug Resistance (TDR) with focus on the protease gene. RNA was extracted from blood samples of 72 newly diagnosed HIV-1 patients attending some HIV testing and counselling clinics from August 2016 to July 2017. Protease fragments were amplified with specific primers by RT-PCR followed by nested PCR. The amplified products were sequenced using the ABI 360 sequencer, edited with Geneious version 9.1.5 and translated into amino acid with BioEdit software. Drug related resistance mutation (DRMs) analysis was performed on all the protease sequences in accordance with the 2009 WHO list of surveillance drug resistance mutations by submitting the edited sequences to Stanford HIV drug interpretation programme and the international AIDS society-USA guidelines for query of drug resistance associated mutations while phylogenetic analysis was performed using MEGA 6 to allocate all viral sequences into subtypes. In the study, a total of 52/72 (71.1%) reliable HIV-1 protease sequences were obtained in which subtyping and drug resistance mutations were performed. Two (3.8%) major Protease resistance associated mutation (V82A/L and L90M) were observed while another polymorphism like L10F, T74S, Q58E, L10I/V and M46V were also identified. Phylogenetic analyses delineated all the sequences as HIV-1 subtype C. Chapter 4 describes the prevalence and the determinants of late presentation amongst newly diagnosed HIV positive individuals in the Eastern Cape. It indicates the extent of the prevalence of patients presenting to care and at what HIV stage they were assessing health care services since the inception of the ‘test and treat’ strategy. It is a cross-sectional study where a total of 335 newly diagnosed patients were recruited consecutively be-tween August 2016 and July 2017. Late presenter for HIV care was defined in accordance with the European Late Presenter Consensus working group as a patient who reports for care when the CD4 count is below 350 cells/μL and/or when there is an established Aids- xxi defining clinical condition, irrespective of CD4 count. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of late HIV diagnosis. The study showed that 60% of patients were late presenters, with 35% presenting with advanced disease. The major determinants identified were being male and low level of education. This led to recommendations directed at ensuring programmes that targets men in identifying their HIV status and assess care at early stage to prevents the morbidity and mortality associated with delayed presentation. Also, it was recommended that effort should be made to improve access to education and also include HIV related topics into the educational curriculum. Chapter 5 aimed to describe the prevalence and determinants of DM amongst newly diagnosed HIV positive individuals. This is a cross-sectional study which recruited 335 patients between August 2016 and September 2017. Definition for diabetes mellitus was made based on the SEDMSA 2015 guideline of HBA1C of above 6.5%. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of abnormal glycated haemoglobin. Findings showed the prevalence of DM at about 6% amongst newly diagnosed HIV positive individuals. This is similar to findings in other study within the country, but a bit lower than what was obtained in the developed countries. The role of older age (above 40 years) as predisposing factor to development of diabetes in newly diagnosed HIV positive individual was well noted and taken. This ensures that screening for DM should be targeted at elderly HIV positive individuals. The grey area of the appropriate mode of diagnostic test to use to diagnose HIV is still debatable, however, a combination of HBA1c and fasting blood sugar (FBS) may improve the diagnosis of DM in this population group. In chapter 6, the general conclusions, recommendations and future perspectives of the study are reflected.
- Full Text:
- Date Issued: 2019
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