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Arylamine N-Acetyltransferases from mycobacteria : investigations of a potential target for anti-tubercular therapyAbuhammad, Areej January 2013 (has links)
Reactivation of latent infection is the major cause of tuberculosis (TB). Cholesterol is a critical carbon source during latent infection. Catabolism of cholesterol contributes to the pool of propionyl-CoA, a precursor that is incorporated into cell-wall lipids. Arylamine N-acetyltransferase (NAT) is encoded within a gene cluster that is involved in the sterol-ring degradation and is essential for intracellular survival. NAT from M. tuberculosis (TBNAT) can utilise propionyl-CoA and therefore was proposed as a target for TB-drug development. Deleting the nat gene or inhibiting the NAT enzyme prevents intracellular survival and results in depletion of cell-wall lipids. NAT inhibitors, including the piperidinol class, were identified by high-throughput screening. The insolubility of recombinant TBNAT has been a major limitation in pursuing it as a drug target. Subcloning tbnat into a pVLT31 vector resulted in a yield of 6-16 mg/litre-bacterial-culture of pure-soluble recombinant TBNAT. The increased yield allowed for extensive screening for crystallisation conditions. However, since a structure was not obtained, the model NAT from M. marinum (MMNAT) was employed to further understand NAT as a target. Screening against a panel of Acyl-CoA cofactors showed that MMNAT can also utilise propionyl-CoA. The MMNAT structure in complex with the high affinity substrate hydralazine was determined (2.1 Å) and the architecture of the arylamine pocket was delineated. A novel mechanism for the acetylation reaction of hydralazine has emerged. It is proposed that the acetyl group is transferred from acetyl-CoA to the heterocyclic aromatic nitrogen of hydralazine, which explains the immediate cyclisation of the acetylated metabolite into an N-methyltriazolophthalazine. By employing mass spectroscopy, enzyme assays, computational docking and structural studies, a covalent mechanism of inhibition by the piperidinol class was established, and the inhibitor-binding pocket was identified. Inhibitors with new scaffolds were identified using the in silico 3D-shape screening and thermal shift assay.
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Generation of a database of mass spectra patterns of selected Mycobacterium species using MALDI-ToF mass spectrometryOduwole, Elizabeth O. 12 1900 (has links)
Thesis (MScMedSc (Pathology. Medical Microbiology))--Stellenbosch University, 2008. / The genus Mycobacterium is a group of acid–fast, aerobic, slow- growing organisms which include
more than 90 different species. A member of this genus, Mycobacterium tuberculosis, belonging to
the Mycobacterium tuberculosis complex (MTB), is the causative agent of tuberculosis (TB). This
disease is currently considered a global emergency, with more than 2 million deaths and over 8
million new cases annually. TB is the world’s second most common cause of death after
HIV/AIDS. About one-third of the world’s population is estimated to be infected with TB. This
catastrophic situation is further compounded by the emergence of Multi Drug Resistant tuberculosis
(MDR-TB) and in more recent times, Extensive Drug Resistant tuberculosis (XDR-TB). Early
diagnosis is critical to the successful management of patients as it allows informed use of
chemotherapy. Also, early diagnosis is also of great importance if the menace of MDR-TB and
XDR-TB is to be curbed and controlled.
As MTB is highly infectious for humans, it is of paramount importance that TB be diagnosed as
early as possible to stop the spread of the disease. Traditional conventional laboratory procedures
involving microscopy, culture and sensitivity tests may require turnaround times of 3-4 weeks or
longer. Tremendous technological advancement over the years such as the advent of automated
liquid culture systems like the BACTEC® 960 and the MGITTM Tube system, and the development
of a myriad of molecular techniques most of which involves nucleic acid amplification (NAA) for
the rapid identification of mycobacterial isolates from cultures or even directly from clinical
specimens have contributed immensely to the early diagnosis of tuberculosis. Most of these NAA
tests are nevertheless fraught with various limitations, thus the search for a rapid, sensitive and
specific way of diagnosing tuberculosis is still an active area of research. The search has expanded to areas that would otherwise not have been considered ‘conventional’ in diagnostic
mycobacteriology. One of such areas is mass spectrometry.
This study joins the relatively few studies of its kind encountered in available literature to establish
the ground work for the application of mass spectrometry, specifically Matrix Assisted Laser
Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-ToF MS) in the field of
diagnostic mycobacteriology. This is an area which is in need of the speed, sensitivity and
specificity that MALDI-ToF technique promises to offer. Since this technology is still in its
infancy, the use of utmost care in the preparation of reagents, and the handling and storage of the
organisms used to generate reference mass spectra for the database cannot be overemphasized.
Similarly, the optimization of certain crucial experimental factors such as inactivating method and
choice of matrix is of paramount importance.
The main aim of this thesis was to generate a database of reference mass spectra fingerprints of
selected (repository) Mycobacterium species. This necessitated the standardization of an
experimental protocol which ensured that experimental factors and the various instrument
parameters were optimized for maximum spectra generation and reproducibility. A standard
operating procedure (SOP) for generating the database of reference mass spectra finger print of
selected Mycobacterium species was developed and used to investigate the ability of the database to
differentiate between species belonging to the same clinical disease complex as well as the nontuberculosis
complex.
The findings of this study imply that if the defined protocol is followed, the database generated has
the potential to routinely identify and differentiate (under experimental conditions) more species of Mycobacterium than is currently practical using PCR and its related techniques. It is therefore a
realistic expectation that when the database is clinically validated and tested in the next phase of the
study, it will contribute immensely to the diagnosis of tuberculosis and other mycobacterioses. It
will also aid in the identification of emerging pathogens particularly amongst the non-tuberculous
mycobacteria.
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Evaluation of anti-tuberculosis responses in humans using different complementary immunological techniquesGutschmidt, Andrea 03 1900 (has links)
Thesis (MSc MedSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Background
The QuantiFERON In-Tube (QFT IT) assay is an Interferon-gamma release assay
(IGRA) which is currently used to detect Mycobacterium tuberculosis (M. tb) infection. It
however cannot differentiate between latent infection and active tuberculosis (TB)
disease. In an attempt to improve this tool to accurately diagnose active TB, the release
of a variety of markers should be assessed in combination with Interferon gamma (IFN-
γ). Luminex analysis was previously done on QFT plasma and promising candidates
were identified which could be of great value in treatment response studies. IFN-γ
ELISpot, are not only used to detect M.tb infection, but is also implicated in vaccine trails
to assess immunogenicity. The IFN-γ ELISpot and flow cytometry are the most common
assays to assess these phenomena during clinical trials. Our aim therefore was to
develop a multi platform immune analysis assay using the QFT IT system.
Study design and method
The first approach of this study was to optimize the QFT IT assay for flow
cytometry applications. The following questions formed part of the optimization study:
How does the QFT whole blood assay (QFT-WBA) compare to the currently used WBA?
Is antigen re-stimulation required after the initial incubation time and for how long should
cells be re-stimulated in the presence of Brefeldin A? The second approach was to use
the optimized QFT-WBA for community controls (CTRL), household contacts (HHC) and
TB cases, which were recruited from the high TB incidence areas Ravensmead, Uitsig
and Elsies River. The infection status of each participant was determined by IFN-γ ELISA and Luminex analysis was performed to measured wide range of cytokine
expression. In addition immune cell markers like CD14, CD4, CD8, CD19, and T cell
receptor gamma delta (TCRγδ) were characterized; polyfunctional characteristics (IFN-γ,
Tumor necrosis factor-alpha (TNF-α) and Interleukin-2 (IL-2)) and proliferation (Ki-67+)
of T cells determined by flow cytometry.
Results
After stimulating the whole blood of the study participants for 22 hours with the M.
tb specific antigens, early secreted antigenic target 6 kDa (ESAT-6), culture filtrate
protein-10 kDa (CFP-10) and TB7.7 the levels of TNF-α producing CD4 T cells were
elevated in TB cases compared to HHCs. After stimulating the whole blood for 6 days
TNF-α producing T cells declined in TB cases and HHC showed a higher expression.
CD40L+CD4+ (p=0.0225) was increased in HHC while IL-9+CD8+ (0.3230) was
decreased in HHC compared to TB cases. Other markers such as IL-5(AG-NIL), IL-13(Ag-
NIL), FGF basicAg, GM-CSFNIL, VEGFNIL/(Ag-NIL), MIP-1βAg and MCP-1Ag/(Ag-NIL) showed
significant differences between HHC and TB cases.
Conclusions
The responses in the QFT-based assay were generally comparable to the WBA
that is routinely used. The differences of TNF-α expression seen in QFT-WBA and QFTLPA
could be explained by the fact that effector T cell responses were measured in the
short term assay and the central memory T cell responses in the long term assay. Our
study therefore shows that the QFT-based tests can be used to simultaneously assess a
wide range of immunological markers and not only IFN-γ expression. / AFRIKAANSE OPSOMMING: Agtergrond
Die QuantiFERON In Tube (QFT IT) toets is ‘n Interferon-gamma vrystellingstoets
(IGRA) wat huidiglik dien as ‘n maatstaf van Mycobacterium tuberculosis (M. tb) infeksie.
Hierdie toets kan egter nie onderskei tussen latente infeksie en aktiewe tuberkulose
(TB) nie. ‘n Noemenswaardige verbetering in die vermoë van hierdie toets om aktiewe
TB te diagnoseer, berus op die studie van ‘n verskeidenheid vrygestelde merkers,
insluitend Interferon gamma (IFN-γ). In vorige Luminex studies op QFT plasma, is
belowende kandidate geïdentifiseer wat van groot waarde kan wees vir studies wat
fokus op die reaksie tot behandeling. Die IFN-γ ELISpot dien nie net as ‘n maatstaf van
M.tb infeksie nie, maar word ook in vaksienproewe betrek om die aard van immuniteit te
ondersoek. Die IFN-γ ELISpot toets sowel as vloeisitometriese toetse, is van die mees
algemene toetse om hierdie verskynsels te meet, tydens kliniese proewe. Die doel van
hierdie studie was dus om die QFT IT sisteem te ontwikkel as ‘n basis vir ‘n multiplatform
immunologiese analiseringstoets.
Studie ontwerp en metode
Die inleidende benadering van hierdie studie was die optimisering van die QFT IT
toets, vir vloeisitometrie doeleindes. Die volgende vrae het deel uitgemaak van die
optimiseringstudie: Hoe vergelyk die QFT heelbloedtoets (QFT-WBA) met huidige WBAs
wat in gebruik is? Word meermalige antigeenstimulasies benodig na die oorspronklike
inkubasieperiode en hoe lank moet die tydperk wees vir sellulêre opvolgstimulasie, in
die teenwoordigheid van Brefeldin A? As ‘n tweede benadering, was om die geoptimiseerde QFT-WBA te gebruik vir gemeenskapskontroles (CTRL), huishoudelike
kontakte (HHC) en TB gevalle. Al drie hierdie groepe was opgeneem uit Ravensmead,
Uitsig en Elsies Rivier, areas met betreklik hoë vlakke van TB infeksie. Elke persoon in
die studie se vlak van infeksie is vasgestel met behulp van die IFN-γ ELISA en Luminex
analiese was uitgevoer, om ‘n wye verskeidenheid uitdrukkingsvlakke van sitokiene te
meet. Dies meer, was immuunselmerkers soos CD14, CD4, CD8, CD19 en T sel
reseptor gamma delta (TCRγδ) gekarakteriseer. Meervuldige funskionele karakteristieke
(IFN-γ, Tumor nekrose faktor-alpha (TNF-α) en Interleukin-2 (IL-2)) en
vermenigvuldiging van T-selle, was vasgestel deur middel van vloeisitometrie.
Resultate
Nadat die heelbloed van studiedeelnemers gestimuleers was met M. tb spesifieke
antigene, vroeë afskeidings antigeniese teiken 6kDa (ESAT-6), kultuurfiltraatproteïn
10kDa (CFP-10) en TB7.7, vir 22 uur, was gevind dat vlakke van TNF-α produserende
CD4 T selle hoër was in TB pasïente, in vergelyking met HHCs. Nadat die heelbloed vir
6 dae gestimuleer was, het die vlak van TNF-α produserende T-selle afgeneem in TB
pasïente, terwyl dit hoër was in HCC. CD40L+CD4+ (p=0.0225) het hoër vlakke bereik
in HHC, terwyl IL-9+CD8+ (0.3230) vlakke afgeneem het, in vergelyking met TB
pasïente. Ander merkers soos,onder andere, IL-5(AG-NIL), IL-13(Ag-NIL), FGF basicAg, GMCSFNIL,
VEGFNIL/(Ag-NIL), MIP-1βAg and MCP-1Ag/(Ag-NIL), het noemenswaardige verskille
geopenbaar tussen HHC en TB pasïente.
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A retrospective study of the clinical management and treatment outcomes of patients established on antiretroviral therapy who are newly diagnosed with tuberculosis in the public sector, KwaZulu-NatalVeerasami, Sowbagium 03 1900 (has links)
Thesis (MCurr)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Taking into consideration the long duration of standard treatment for Mycobacterium
tuberculosis (TB), the high prevalence of HIV co-infection and the growing prevalence of
drug-resistant TB, there is an urgent need for improved treatment approaches for TB and
HIV. However, there is inadequate information regarding the burden being placed on the
Department of Health (DOH) systems by the current treatment of patients established on
Antiretroviral Therapy (ART) who are newly diagnosed with TB, and by their clinical
management.
The aim of the study was to determine what proportion of patients established on ART
were newly diagnosed with TB, and what their clinical and treatment outcomes were in
different public sector settings in the eThekwini Region, KwaZulu-Natal (KZN). Approval
for the study was obtained from the Human Research Committee of Stellenbosch
University and from the Biomedical Research Committee, KZN.
The study used a retrospective, quantitative, cohort technique at both TB and ART clinics
at three sites in the eThekwini region, KZN. These sites were DOH clinics and were
selected as they all had a TB clinic and a DOH-registered ART clinic. The study focused
on a period of one year prior to a patient established on ART developed TB. The study
population comprised all TB patients who attended the selected DOH clinics.
A data collection tool was developed and pilot-tested. A small sample of patient files
(n=15, representing 2% of the study population) was randomly selected; five from each
site. The files and data were excluded from the main study.
A total of 1824 files (579 from the TB clinics and 1245 from the ART clinics) were
reviewed. The data were captured into an electronic database (EpiData Version 3.3) and
analyzed using STATA (Version 11.0) with the assistance of a statistician. The findings show that of the study sample from the TB clinics (N=579), 78% (454/579)
were newly diagnosed with TB. Of the new TB cases, 90% (409/454) had pulmonary TB
and 71% (413/579) were HIV-positive. Nearly 50% (68/137) of the patients had
commenced ART prior to TB diagnosis and treatment, and 14% (19/137) had commenced
ART after TB. Of those who commenced ART prior to TB diagnosis and treatment, 29%
(20/68) had commenced ART more than three months prior to acquiring TB. The findings from the ART clinics show that of the files (N=1245) reviewed, 40%
(501/1245) had TB, and of these 8% (42/501) developed TB after three months or more of
ART.
Missing data in the patient medical files was a major challenge. The lack of recorded data
about ART in the TB clinics and about TB in the ART clinics suggests suboptimal clinical
management and poor integration of HIV and TB services. It was therefore not possible to
derive a combined HIV-TB outcome measure.
Recommendations to promote and implement the integration of TB and HIV services
included policy changes and implementation, management and practice suggestions,
education and training to integrate TB/HIV services and increase research to identify gaps
in clinical management and to improve integration of services. / AFRIKAANSE OPSOMMING: Met inagneming van die lang duur van die standaard behandeling vir Mycobacterium
tuberkulose (TB), hoë voorkoms van MIV-infeksie en die groeiende voorkoms van
dwelmweerstandige TB, is daar ’n dringende behoefte aan verbeterde
behandelingbenaderings vir TB en MIV. Daar is egter ’n gebrek aan inligting oor die las
geplaas op die Departement van Gesondheid (DvG) se stelsels deur die huidige
behandeling van pasiënte op antiretrovirale terapie (ART) wat gediagnoseer is met TB en
deur hul kliniese bestuur.
Die doel van die studie was om vas te stel watter persentasie van pasiënte wat op ART
gevestig is, wel met TB gediagnoseer is, en wat hul kliniese en behandeling-uitkomste was
in verskillende openbare-sektorinstellings in die eThekwini-streek, KwaZulu-Natal (KZN).
Goedkeuring vir die studie is verkry van die Menslike Navorsingskomitee van die
Universiteit van Stellenbosch en van die Biomediese Navorsingskomitee, KZN.
Die studie het gebruik gemaak van ’n retrospektiewe, kwantitatiewe ‘cohort’-tegniek by
beide TB en ARB-klinieke op drie plekke in die eThekwini-streek, KZN. Hierdie terreine
was DvG-klinieke en is gekies omdat hulle almal oor ’n TB-kliniek en 'n DvGgeregistreerde
ART-kliniek beskik. Die studie het gefokus op ’n tydperk van een jaar voor
’n pasiënt wat op ART is, TB ontwikkel het. Die studiepopulasie bestaan uit alle TBpasiënte
wat die geselekteerde DvG-klinieke bygewoon het. ’n Data-insamelinginstrument is ontwikkel en getoets. ’n Klein voorbeeld van die
pasiëntlêers (n = 15, 2% van die studie bevolking verteenwoordig) is ewekansig gekies:
vyf uit elke plek, en die data is vervat in ’n elektroniese databasis (EpiData Version 3,3).
’n Totaal van 1824 lêers (579 in die TB-klinieke en 1245 lêers in die ART-klinieke) is
ondersoek. Die data is ontleed deur gebruik te maak van Stata (weergawe 11,0) met die
hulp van ’n statistikus. Die bevindinge toon dat van die studiemonster in die TB-klinieke (N = 579), 78% (454/579)
met TB gediagnoseer is. Van die nuwe TB-gevalle, het 90% (409/454) pulmonêre TB
gehad en was 71% (413/579) MIV-positief. Byna 50% (68/137) van die pasiënte het ART
begin vóór hulle TB-diagnose en -behandeling, en 14% (19/137) ART ná TB. Van dié wat
ART voor TB-diagnose en -behandeling begin het, het 29% (20/68) meer as drie maande
voor die opdoen van TB met ART begin. Die bevindinge van die ART-klinieke toon dat van
die lêers (N = 1245) wat bestudeer is, 40% (501/1245) TB het, en hiervan het 8% (42/501)
TB na drie of meer maande van ART ontwikkel.
Ontbrekende data in die pasiënt se mediese lêers was ’n groot uitdaging. Die gebrek aan
aangetekende data oor ART in die TB-klinieke en oor TB in die ART-klinieke dui op
suboptimale kliniese bestuur en swak integrasie van MIV- en TB-dienste. Dit was dus nie
moontlik om ’n gesamentlike MIV-TB uitkomsmaatreël af te lei nie.
Aanbevelings om die integrasie van TB- en MIV-dienste te bevorder en te implementer,
het beleidveranderinge en -implementering ingesluit, asook bestuur- en praktykvoorstelle,
onderwys en opleiding om TB-/MIV-dienste by DvG-vlak te integreer en meer navorsing
om gapings in die kliniese bestuur te identifiseer en die integrasie van dienste te verbeter.
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The characterisation of N-Acetyltransferase (NAT) in Mycobacterium tuberculosisSholto-Douglas-Vernon, Carolyn 03 1900 (has links)
Thesis (PhD (Molecular Biology and Human Genetics))--University of Stellenbosch, 2005. / 157 leaves single sided printed, preliminary pages i-xvii and numbered pages 1-141. Includes bibliography, and abbreviations and a list of figures. / ENGLISH ABSTRACT: A gene coding for Arylaminie N-acetyltransferase (NAT) has been found in Mycobacterium
tuberculosis, the casual agent of tuberculosis (TB). N-acetyltransferase acetylates and inactivates
isoniazid (INH), which is a front line drug used in TB therapy. A guanine to adenine SNP at basepair
619 (G619A) has previously been identified in this gene, which results in a glycine to arginine
change at amino acid 207 (G207R) (Upton et al. 2001). In this study the nat gene was further
characterised. The frequency of the G619A SNP was analysed in 37 M tuberculosis strain families
found in the Western Cape Province of South Africa, and it was found that the G619A SNP is
conserved in two strain families (strain family 3 and strain family 28). Further sequence analysis
identified a new thymine to cytosine SNP at base-pair 529 (T529C) resulting in a tyrosine to
histidine change at amino acid 177 (Yl77H). This SNP was found only in isolates from strain
family 3. These results imply that these SNPs may be used in epidemiology studies to classify
isolates into these strain families.
Using Real Time PCR, the expression of nat in M bovis BCG and M tuberculosis (reference
strain H37Rv) was determined over a 7 and 28 day growth cycle, respectively. Using 16S rRNA as
an endogenous control, the nat gene was shown to be expressed early during the growth curve and
reach its maximum expression level at approximately mid-log phase. The expression of nat was
induced in drug susceptible M tuberculosis isolates (reference strain H37Rv and isolate 1430
containing both SNPs) exposed to INH at a concentration of O.Oll-lg/ml, but minimal change in
expression was observed in resistant isolates (isolate 816) exposed to INH at the same
concentration. Mycobacterium bovis BCG cultures exposed to INH, at a final concentration of
0.28I-lg/ml, showed an increase in protein production. The increase of nat mRNA and NAT protein
in M tuberculosis and M bovis BCG, respectively, implies that INH affects the expression of
NAT.
The NAT protein was localised to all fractions of the cell in Mycobacterium smegmatis, M bovis
BCG and M tuberculosis, using the Western blot technique. However, protein fractions from the
cell envelope region showed a protein (detected with specific NAT antibodies) that ran at a higher
molecular weight (MW). This implies that the cytosolic hydrophilic NAT undergoes some type of
post-translational process that may make it hydrophobic, and enable it to pass into the cell
envelope region.
These results show for the first time how nat is expressed during the entire growth cycle of M
tuberculosis and M. bovis BeG. It was shown that nat is expressed early during the growth cycle
of the bacterium reaching maximum expression levels at mid-log phase. These results are in
concordance with those obtained using M. smegmatis nat mutants, which taken together, show
that early expression of nat is important for early growth and development of mycobacteria. The
results in this study also showed that NAT appeared to be translocated into the cell envelope of
the bacterium, implying that NAT may be involved in one of the pathways needed for complete
formation of the cell envelope. These results suggest that NAT may be an important target for
drug development, as inhibitors of NAT could result in hindered growth and hence spread of the
bacterium within its host. Inhibitors may also result in the incomplete development of the cell
wall, enabling the host to combat the disease using its own immune system.
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Hearing loss amongst dr-tb patients that received extended high frequency pure tone audiometry monitoring (kuduwave) at three dr-tb decentralized sites in Kwazulu-NatalRudolph-Claasen, Zerilda 10 1900 (has links)
Doctor Educationis / Ototoxic induced hearing loss is a common adverse event related to aminoglycosides used in Multi
Drug Resistant -Tuberculosis treatment. Exposure to ototoxic drugs damages the structures of the
inner ear. Symptomatic hearing loss presents as tinnitus, decreased hearing, a blocked sensation,
difficulty understanding speech, and perception of fluctuating hearing, dizziness and
hyperacusis/recruitment. The World Health Organization (1995) indicated that most cases of ototoxic
hearing loss globally could be attributed to treatment with aminoglycosides.
The aim of the study was to determine the proportion of DR-TB patients initiated on treatment at
three decentralized sites during a defined period (1st October to 31st December 2015) who
developed ototoxic induced hearing loss and the corresponding risk factors, whilst receiving
audiological monitoring with an extended high frequency audiometer (KUDUwave).
A retrospective cross-sectional study was conducted. Cumulatively across the three decentralized
sites, 69 patient records were reviewed that met the inclusion criteria of the study. The mean age of
the patients was 36.1, with a standard deviation (SD) of 10.7 years; more than half (37) were female.
Ototoxicity , a threshold shift, placing patients at risk of developing a hearing loss was detected in
56.5% (n=39)of patients and not detected in 30.4%(n=21).The remaining 13,1% (n=9)is missing
data. As a result, the regimen was adjusted in 36.2% of patients. .
From the 53 patients who were tested for hearing loss post completion of the injectable phase of
treatment, 22.6% (n=12) had normal hearing, 17.0 % (n=9) had unilateral hearing loss, and 60.4%
(n=32) had bilateral hearing loss. Therefore, a total of 41 patients had a degree of hearing loss:
over 30% (n=22)had mild to moderate hearing loss, and only about 15% (n=11)had severe to
profound hearing loss. Analysis of risk factors showed that having ototoxicity detected and not
adjusting regimen significantly increases the risk of patients developing a hearing loss.
The key findings of the study have shown that a significant proportion of DR-TB patients receiving
an aminoglycoside based regimen are at risk of developing ototoxic induced hearing loss, despite
receiving audiological monitoring with an extended high frequency audiometer that allows for early
detection of ototoxicity (threshold shift).
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[en] A TOOL DEVELOPMENT FOR THE ANALYSIS OF PERFORMANCE OF THE ISDB-T DIGITAL TV STANDARD / [pt] DESENVOLVIMENTO DE UMA FERRAMENTA DE ANÁLISE DE DESEMPENHO PARA O PADRÃO DE TV DIGITAL ISDB-TLUIS EDUARDO ANTUNES DE RESENDE 23 September 2004 (has links)
[pt] TV Digital é um dos assuntos mais discutidos na atualidade,
devido ao
grau de influência que ela exerce sobre toda população,
pelas inovações
propostas que conseqüentemente trarão novas e interessantes
facilidades aos espectadores, e pela corrida tecnológica
que ela está desenvolvendo. O objetivo deste trabalho é o
desenvolvimento de uma ferramenta de análise
de desempenho do padrão de TV Digital japonês ISDB-T.
Através dela é possível identificar as características
positivas e negativas do sistema, fazer uma análise mais
detalhada do padrão e identificar os benefícios que
esta nova tecnologia trás para os telespectadores. Ainda, o
desempenho da transmissão é avaliado através dos resultados
gerados pela ferramenta, sob forma de gráficos, que servem
como método comparativo entre as diversas configurações
possíveis no sistema. Estas comparações permitem
a identificação da configuração ótima para cada tipo do
canal. / [en] Digital TV is one of the most discussed subjects nowadays,
due to the
influence they exerce in population, the services offered
by innovations and
the technological race developed.
A tool which has been developed to asses the quality of
ISDB-T system
trough the simulation will be discussed in this work. This
tool enable us to
test the data transmission performance of all ISDB-T system
configuration.
Situations simulated involves AWGN channel and, to evaluate
one most
disturbing interference on television signal, AWGN plus
multipath channel
is also under consideration. The results are shown in
graphics, which allow
comparisons among all possible configurations and to know
the performance
of this system.
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Patient Characteristics and Treatment Outcomes Among Tuberculosis Patients in Sierra LeoneSesay, Mohamed Lamin 01 January 2017 (has links)
Despite decades of the implementation of the directly observed therapy short-course (DOTS), Sierra Leone is ranked among the 30 highest TB-burdened countries. Several factors account for unfavorable treatment outcomes, among which are patient characteristics. Previous studies have only focused on treatment compliance without any consideration for the factors that lead to noncompliance to treatment. The purpose of this study was to investigate patient characteristics that are associated with treatment noncompliance (treatment not completed) among TB patients undergoing the DOTS program in Sierra Leone. A retrospective longitudinal quantitative design was used to analyze secondary data from the completed records of 1,633 TB patients, using the Andersen's behavioral model of health services utilization as a theoretical framework work. Descriptive statistics and bivariate and multivariate logistic regressions were used to analyze the data. The results show that there was no significant association between treatment completion and age, gender, and TB-case category. On the other hand, being HIV-positive decreases the odds of treatment completion. Also, the educational level, geographic location, and year of treatment were significantly associated with treatment completion. Overall, program performance improved as the number of dropouts decreased significantly between 2013 and 2015. The social change implication of this study was that it identified HIV-positive patients and rural communities as areas needing specific attention such as the assignment of case managers to ensure compliance thereby improve DOTS program performance, thereby reducing the incidence and transmission of TB
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Perceptions of Private Medical Practitioners towards the Nigerian National Tuberculosis Treatment GuidelinesOsakwe, Chijioke Pius 01 January 2018 (has links)
Tuberculosis (TB) is a major public health problem in many parts of the world. Nigeria is one of the 30 countries in the world that has the highest burden of TB. Private medical practitioners in Nigeria play an important role in health care delivery. Motivating them to adhere to TB treatment guidelines in managing persons suspected of having TB or diagnosed with the disease is one of the strategies employed by the National Tuberculosis Program to Reduce the Burden of TB. Few studies were identified which used qualitative study approaches to study the perceptions of these practitioners towards the TB treatment guidelines. The overarching question asked the study participants centered on eliciting their perceptions towards the guidelines. Guided by the theory of planned behavior, this qualitative narrative study explored the perceptions of private medical practitioners in Anambra State, Nigeria towards the Nigerian National TB Treatment Guidelines. To elicit these perceptions, in-depth interviews were conducted on 11 purposefully selected practitioners. Data analysis comprised coding of data obtained and extracting themes from them. The QSR Nvivo 11 helped to manage data. The main finding of the study was that the practitioners perceived the treatment guidelines to be adequate to meet most of their needs in the diagnosis and treatment of TB patients. Other key findings were that provision of financial incentives and regular training will motivate collaboration with the TB program and adherence to the guidelines. Positive social change may occur by insight being gained into how private medical practitioners view the treatment guidelines and how this knowledge will lead to improved management of TB patients. This may in turn result in the reduction in the morbidity and mortality associated with TB in Nigeria.
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Factors affecting treatment outcomes in tuberculosis (TB) patients in the Limpopo Province, South AfricaGafar, Mohammed Mergni January 2013 (has links)
Thesis (M. Pharm) --University of Limpopo, 2013 / Tuberculosis (TB) threatens the public health all over the world. South Africa is ranked fifth on the list of 22 high burden countries. SA has not achieved the international targets for cure
rate and default rate yet. This is attributed to high HIV/AIDS prevalence and emergence of multi- drug resistant TB. Limpopo Province experiences poor TB treatment outcome, in spite of the adoption of strategies that proved globally that they can improve the outcome. The factors affecting treatment outcome in Limpopo Province are as yet undocumented. The
specific objectives of this study were to determine the demographic profile of TB patients in the Limpopo Province; to investigate the treatment outcomes and to establish the relationship between age, gender, HIV status, treatment regimen and health facility level and the treatment outcomes in patients diagnosed with pulmonaryTB for period between 2006- 2010,
inclusive, in Limpopo Province.
Method
Retrospective data for the period between 2006 and 2010 (inclusive) were reviewed, and
1200 records of cases of confirmed TB patients were sampled from the ETR.net provincial
database. All these patients were diagnosed and treated according to guidelines adopted by the national TB control programme. Standard WHO definitions were used to classify the TB treatment outcome. Chi squire test was used to investigate the association between age, gender, diagnostic category and treatment regimen and treatment outcome.
Results
Of the 1200 TB cases sampled, 656 (54%) were male. Most of them fell within the age group
22- 55 years (n=871; 72.5%)). According to diagnostic category, 1035 (86.2%) were new
cases; 962 (80.1%) cases received regimen I (two months of rifampicin [R], isoniazid [H],
pyrazinamide [Z} and ethambutol [E] followed by four months of rifampicin and isoniazid,
2RHZE+ 4RH); 893 (74.4%) cases had successful treatment; 118 (9.8%) defaulted on
treatment; 26 (2.2%) had treatment failure, and 163 (13.6%) died. There was a strong
association between age (P <0.001), diagnostic category (P < 0.001), treatment regimen (P < 0.001), and health facility level (P< 0.001) and treatment outcome. The success treatment was highly significant (P <0.001) for the cases that fell within the age group 3- 6 years, those that were diagnosed as new cases, those that received treatment at mine health facilities or were
treated with regimen III (2RHZ + 4RH). While the default rate was highly significant (P<
0.05) for the cases aged 7- 12 or 22- 55 years, patients that had history of defaulting, and those that received treatment at a community health centre or village health facilities –. treatment failure was highly significant (P< .05) for Those fell within age group 22-55 or
56- 74 years, those had initial treatment failure, those that received treatment at hospital or mobile health facilities or treated with regimen II (3RHZES + 5RH) while the death rate was highly significant (P< 0.05) for the cases either fall within age group 0-2, 22- 55 or 56- 74
years, had initial failure, received treatment at hospital or village health facilities or treated with regimen). The un success rate was very highly significant (P< 0.001) for those either characterized by; fall within age group 22- 55 years, had initial failure, received treatment at
hospital or village health facilities or treated with regimen II.
Conclusion
TB treatment outcome are poor in the Limpopo Province, particularly among patients with
previous history of TB treatment, those receiving treatment in hospitals, or those being treated with first line regimen II. This situation requires that the TB control programme and other relevant programmes be strengthened, for instance through integration at facility level,
towards more effective response to the challenges which hamper progress towards
international targets on TB. Further studies are needed to address the effect of HIV status and AIDS, CD4+ cell counts, anti-retroviral therapy (ART), cotrimoxazole preventive therapy (CPT) and radiological presentation, and their effect on TB treatment outcome in Limpopo Province. Those data are not routinely captured on ETR.net, hence were not included in the
present study.
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