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Search Results: 1 - 10 of 32412 matches for " John Matovu "
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Trypanosoma brucei rhodesiense Transmitted by a Single Tsetse Fly Bite in Vervet Monkeys as a Model of Human African Trypanosomiasis
John K. Thuita,John M. Kagira,David Mwangangi,Enock Matovu,C. M. R. Turner,Daniel Masiga
PLOS Neglected Tropical Diseases , 2008, DOI: 10.1371/journal.pntd.0000238
Abstract: We have investigated the pathogenicity of tsetse (Glossina pallidipes)-transmitted cloned strains of Trypanosoma brucei rhodesiense in vervet monkeys. Tsetse flies were confirmed to have mature trypanosome infections by xenodiagnosis, after which nine monkeys were infected via the bite of a single infected fly. Chancres developed in five of the nine (55.6%) monkeys within 4 to 8 days post infection (dpi). All nine individuals were successfully infected, with a median pre-patent period of 4 (range = 4–10) days, indicating that trypanosomes migrated from the site of fly bite to the systemic circulation rapidly and independently of the development of the chancre. The time lag to detection of parasites in cerebrospinal fluid (CSF) was a median 16 (range = 8–40) days, marking the onset of central nervous system (CNS, late) stage disease. Subsequently, CSF white cell numbers increased above the pre-infection median count of 2 (range = 0–9) cells/μl, with a positive linear association between their numbers and that of CSF trypanosomes. Haematological changes showed that the monkeys experienced an early microcytic-hypochromic anaemia and severe progressive thrombocytopaenia. Despite a 3-fold increase in granulocyte numbers by 4 dpi, leucopaenia occurred early (8 dpi) in the monkey infection, determined mainly by reductions in lymphocyte numbers. Terminally, leucocytosis was observed in three of nine (33%) individuals. The duration of infection was a median of 68 (range = 22–120) days. Strain and individual differences were observed in the severity of the clinical and clinical pathology findings, with two strains (KETRI 3741 and 3801) producing a more acute disease than the other two (KETRI 3804 and 3928). The study shows that the fly-transmitted model accurately mimics the human disease and is therefore a suitable gateway to understanding human African trypanosomiasis (HAT; sleeping sickness).
Academic Self-Concept and Academic Achievement among University Students
Musa Matovu
International Online Journal of Educational Sciences , 2012,
Abstract: The purpose this study was to investigate academic self-concept and academic achievement among university students. The academic self-concept information among university students was collected using the Liu and Wang (2005) academic self-concept scale which was composed of two sub-scales; academic confidence and academic effort scales. The study was conducted on 394 university students; males and females from different levels of study and faculties in a public university in Malaysia. MANOVA was used to analyse the collected data and the results revealed that there was a statistically significant effect of gender on academic effort and academic achievement, while also a statistically significant difference was shown in faculties on academic achievement. Again a difference was noted in the interaction between gender, faculties, and levels of study on academic achievement. The Post Hoc results indicated that a statistically significant difference existed in between the faculties Arts and Human Sciences.
Methods to Determine the Transcriptomes of Trypanosomes in Mixtures with Mammalian Cells: The Effects of Parasite Purification and Selective cDNA Amplification
Julius Mulindwa,Abeer Fadda,Clementine Merce,Enoch Matovu,John Enyaru,Christine Clayton
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002806
Abstract: Patterns of gene expression in cultured Trypanosoma brucei bloodstream and procyclic forms have been extensively characterized, and some comparisons have been made with trypanosomes grown to high parasitaemias in laboratory rodents. We do not know, however, to what extent these transcriptomes resemble those in infected Tsetse flies - or in humans or cattle, where parasitaemias are substantially lower. For clinical and field samples it is difficult to characterize parasite gene expression because of the large excess of host cell RNA. We have here examined two potential solutions to this problem for bloodstream form trypanosomes, assaying transcriptomes by high throughput cDNA sequencing (RNASeq). We first purified the parasites from blood of infected rats. We found that a red blood cell lysis procedure affected the transcriptome substantially more than purification using a DEAE cellulose column, but that too introduced significant distortions and variability. As an alternative, we specifically amplified parasite sequences from a mixture containing a 1000-fold excess of human RNA. We first purified polyadenylated RNA, then made trypanosome-specific cDNA by priming with a spliced leader primer. Finally, the cDNA was amplified using nested primers. The amplification procedure was able to produce samples in which 20% of sequence reads mapped to the trypanosome genome. Synthesis of the second cDNA strand with a spliced leader primer, followed by amplification, is sufficiently reproducible to allow comparison of different samples so long as they are all treated in the same way. However, SL priming distorted the abundances of the cDNA products and definitely cannot be used, by itself, to measure absolute mRNA levels. The amplification method might be suitable for clinical samples with low parasitaemias, and could also be adapted for other Kinetoplastids and to samples from infected vectors.
Larvicidal Activity of Tephrosia vogelii Crude Extracts on Mosquito Larval Stages
H. Matovu,D. Olila
Research Journal of Biological Sciences , 2012,
Abstract: The use of natural products and biological insect control methods is gaining importance because of concerns about the environment, since they are more easily biodegradable. In some parts of Uganda, organic farmers have adopted the use of Tephrosia vogelii, a shrubby, leguminous and woody plant for control of storage pests. However, the efficacy of Tephrosia vogelii crude extracts in the control of Dipteran insect larvae under field conditions has not been well tested. Their use for the control of insect vectors such as mosquitoes has not also been fully evaluated. Tephrosia vogelii plant materials were collected from two selected sites, one on a higher altitude than the other using polythene study. The material was chopped, properly labeled and air-dried in a shade for two weeks. Four solvents where used for extraction: Water, Petroleum ether, Chloroform, Methanol. The extract was dried in an oven at about 32-33 C for several days, after which it was weighed and stored in the fridge at 4 C until the time of exposing the mosquito larvae. Shoot Evening Methanol (SEM) was the most effective among methanol extracts; killing an average of 4.57 mosquito larvae in 8 min while Shoot Evening Water (SEW) was the most effective of water extracts killing an average of 2.57 mosquito larvae in 8 min; hence the SEM was considered to be nearly two times more efficacious than SEW on mosquito larvae, at a concentration of 25%: 10.8% or 2.3:1 SEM: SEW, respectively. Tephrosia vogelii crude extracts could potentially therefore be used to control the larval stages of mosquitoes.
Acaricidal Activity of Tephrosia vogelii Extracts on Nymph and Adult Ticks
H. Matovu,D. Olila
International Journal of Tropical Medicine , 2012,
Abstract: Botanical pesticides exist within nearly all vector disease endemic communities of the world. Natural/ botanical tick control methods offer several advantages over synthetic tick control including environmental preservation since they have shorter residual periods with rapid action. Tephrosia vogelii a shrubby, leguminous and woody plant is one of the potential candidates to provide affordable botanical acaricides. However, its effectiveness in the control of Acarina has not been fully explored in developing countries. Tephrosia vogelii plant materials were collected from two selected sites, one on a higher altitude than the other. The air-dry plant material was crushed into powder; and extracted with a known volume of solvent. The mixture was left to stand for seven days with daily stirring for at least 2 h. Extracts from shoot, cortex and roots have an average yield of 0.06, 0.05 and 0.015 g per one gram of plant raw material, respectively. Shoot and cortex plant parts accumulate relatively high amounts of the active ingredients in Tephrosia compared to the roots; probably explaining why leaves (shoot) are preferred by the local farmers for effective pest control. Methanol, Petroleum ether and Chloroform yield 0.0875, 0.0142 and 0.0172 g per one gram of plant raw material, respectively, indicating a significantly valuable yield when methanol is used for extraction than any of the other two solvents or water. All extracts killed 100% of the exposed ticks but variations where noted in the time taken to achieve 100% exposed tick death. Petroleum ether, chloroform, methanol and water extracts killed 100% of the ticks in an average time of 8.3, 9.7, 10.3 and 1.3 days, respectively; implying that ticks are more susceptible to the active ingredient extracted using petroleum ether relative to the other solvents. Tephrosia crude extracts can potentially, therefore, be used to effectively control ticks in the Ugandan animal production systems. Photosynthesis and plant respiration seem to have an effect on the production and storage of the active ingredients in Tephrosia with the more effective active ingredients being found in the early morning.
Larvicidal Activity of Tephrosia vogelii Crude Extracts on Mosquito Larval Stages
H. Matovu,D. Olila
Research Journal of Biological Sciences , 2007,
Abstract: The use of natural products and biological insect control methods is gaining importance because of concerns about the environment, since they are more easily biodegradable. In some parts of Uganda, organic farmers have adopted the use of Tephrosia vogelii, a shrubby, leguminous and woody plant for control of storage pests. However, the efficacy of Tephrosia vogelii crude extracts in the control of Dipteran insect larvae under field conditions has not been well tested. Their use for the control of insect vectors such as mosquitoes has not also been fully evaluated. Tephrosia vogelii plant materials were collected from two selected sites, one on a higher altitude than the other using polythene study. The material was chopped, properly labeled and air-dried in a shade for two weeks. Four solvents where used for extraction: Water, Petroleum ether, Chloroform, Methanol. The extract was dried in an oven at about 32-33°C for several days, after which it was weighed and stored in the fridge at 4°C until the time of exposing the mosquito larvae. Shoot Evening Methanol (SEM) was the most effective among methanol extracts; killing an average of 4.57 mosquito larvae in 8 min while Shoot Evening Water (SEW) was the most effective of water extracts killing an average of 2.57 mosquito larvae in 8 min; hence the SEM was considered to be nearly two times more efficacious than SEW on mosquito larvae, at a concentration of 25%: 10.8% or 2.3:1 SEM: SEW, respectively. Tephrosia vogelii crude extracts could potentially therefore be used to control the larval stages of mosquitoes.
Sensitivity of direct versus concentrated sputum smear microscopy in HIV-infected patients suspected of having pulmonary tuberculosis
Adithya Cattamanchi, David W Dowdy, J Lucian Davis, William Worodria, Samuel Yoo, Moses Joloba, John Matovu, Philip C Hopewell, Laurence Huang
BMC Infectious Diseases , 2009, DOI: 10.1186/1471-2334-9-53
Abstract: We performed a prospective, blinded evaluation of direct and concentrated Ziehl-Neelsen smear microscopy on a single early-morning sputum sample in HIV-infected patients with > 2 weeks of cough hospitalized in Kampala, Uganda. Direct and concentrated smear results were compared with results of Lowenstein-Jensen culture.Of 279 participants, 170 (61%) had culture-confirmed TB. The sensitivity of direct and concentrated smear microscopy was not significantly different (51% vs. 52%, difference 1%, 95% confidence interval (CI): [-7%, 10%], p = 0.88). However, when results of both direct and concentrated smears were considered together, sensitivity was significantly increased compared with either method alone (64%, 95% CI: [56%, 72%], p < 0.01 for both comparisons) and was similar to that of direct smear results from consecutive (spot and early-morning) specimens (64% vs. 63%, difference 1%, 95% CI: [-6%, 8%], p = 0.85). Among 109 patients with negative cultures, one had a positive direct smear and 12 had positive concentrated smears (specificity 99% vs. 89%, difference 10%, 95% CI: [2%, 18%], p = 0.003). Of these 13 patients, 5 (38%) had improved on TB therapy after two months.Sputum concentration did not increase the sensitivity of light microscopy for TB diagnosis in this HIV-infected population. Given the resource requirements for sputum concentration, additional studies using maximal blinding, high-quality direct microscopy, and a rigorous gold standard should be conducted before universally recommending this technique.Direct sputum smear microscopy is the cornerstone of tuberculosis (TB) diagnosis worldwide [1]. Direct smear microscopy is rapid, inexpensive [2-4], highly specific [5-7], and capable of identifying the most infectious cases of TB [7-9], but its sensitivity is limited, particularly in those with human immunodeficiency virus (HIV) co-infection [10-13]. Processing of sputum with subsequent concentration by centrifugation or sedimentation may increase the
A Combined CXCL10, CXCL8 and H-FABP Panel for the Staging of Human African Trypanosomiasis Patients
Alexandre Hainard,Natalia Tiberti,Xavier Robin,Veerle Lejon,Dieudonné Mumba Ngoyi,Enock Matovu,John Charles Enyaru,Catherine Fouda,Joseph Mathu Ndung'u,Frédérique Lisacek,Markus Müller,Natacha Turck,Jean-Charles Sanchez
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000459
Abstract: Background Human African trypanosomiasis (HAT), also known as sleeping sickness, is a parasitic tropical disease. It progresses from the first, haemolymphatic stage to a neurological second stage due to invasion of parasites into the central nervous system (CNS). As treatment depends on the stage of disease, there is a critical need for tools that efficiently discriminate the two stages of HAT. We hypothesized that markers of brain damage discovered by proteomic strategies and inflammation-related proteins could individually or in combination indicate the CNS invasion by the parasite. Methods Cerebrospinal fluid (CSF) originated from parasitologically confirmed Trypanosoma brucei gambiense patients. Patients were staged on the basis of CSF white blood cell (WBC) count and presence of parasites in CSF. One hundred samples were analysed: 21 from stage 1 (no trypanosomes in CSF and ≤5 WBC/μL) and 79 from stage 2 (trypanosomes in CSF and/or >5 WBC/μL) patients. The concentration of H-FABP, GSTP-1 and S100β in CSF was measured by ELISA. The levels of thirteen inflammation-related proteins (IL-1ra, IL-1β, IL-6, IL-9, IL-10, G-CSF, VEGF, IFN-γ, TNF-α, CCL2, CCL4, CXCL8 and CXCL10) were determined by bead suspension arrays. Results CXCL10 most accurately distinguished stage 1 and stage 2 patients, with a sensitivity of 84% and specificity of 100%. Rule Induction Like (RIL) analysis defined a panel characterized by CXCL10, CXCL8 and H-FABP that improved the detection of stage 2 patients to 97% sensitivity and 100% specificity. Conclusion This study highlights the value of CXCL10 as a single biomarker for staging T. b. gambiense-infected HAT patients. Further combination of CXCL10 with H-FABP and CXCL8 results in a panel that efficiently rules in stage 2 HAT patients. As these molecules could potentially be markers of other CNS infections and disorders, these results should be validated in a larger multi-centric cohort including other inflammatory diseases such as cerebral malaria and active tuberculosis.
New biomarkers for stage determination in Trypanosoma brucei rhodesiense sleeping sickness patients
Natalia Tiberti, Enock Matovu, Alexandre Hainard, John Charles Enyaru, Veerle Lejon, Xavier Robin, Natacha Turck, Dieudonné Mumba Ngoyi, Sanjeev Krishna, Sylvie Bisser, Bertrand Courtioux, Philippe Büscher, Krister Kristensson, Joseph Mathu Ndung'u, Jean-Charles Sanchez
Clinical and Translational Medicine , 2013, DOI: 10.1186/2001-1326-2-1
Abstract: A population comprising 85 T. b. rhodesiense patients, 14 stage 1 (S1) and 71 stage 2 (S2) enrolled in Malawi and Uganda, was investigated. The CSF levels of IgM, MMP-9, CXCL13, CXCL10, ICAM-1, VCAM-1, neopterin and B2MG were measured and their staging performances evaluated using receiver operating characteristic (ROC) analyses.IgM, MMP-9 and CXCL13 were the most accurate markers for stage determination (partial AUC 88%, 86% and 85%, respectively). The combination in panels of three molecules comprising CXCL13-CXCL10-MMP-9 or CXCL13-CXCL10-IgM significantly increased their staging ability to partial AUC 94% (p value < 0.01).The present study highlighted new potential markers for stage determination of T. b. rhodesiense patients. Further investigations are needed to better evaluate these molecules, alone or in panels, as alternatives to WBC to make reliable choice of treatment.Human African trypanosomiasis (HAT), commonly known as sleeping sickness, is a neglected tropical disease caused by the Trypanosoma brucei parasite and transmitted to humans through the bite of the tsetse fly [1]. Two morphologically identical subspecies of parasites are responsible for the disease: Trypanosoma brucei gambiense and T. b. rhodesiense[2]. In both cases, the disease progresses from a haemolymphatic first stage (S1), to a meningo-encephalitic second stage (S2). The latter reflects invasion of the central nervous system (CNS) by the parasites across the blood–brain barrier (BBB) with severe neurological complications, which can ultimately lead to coma and death, when untreated [3]. The two forms of HAT differ in their clinical presentations and geographic distribution. The gambiense form is widespread in Central and Western Africa and is commonly considered to be a chronic infection, which slowly progresses from the first to the second stage. The rhodesiense form of sleeping sickness, that affects communities in Eastern Africa, is a more aggressive illness, which rapidly progresses
Neopterin Is a Cerebrospinal Fluid Marker for Treatment Outcome Evaluation in Patients Affected by Trypanosoma brucei gambiense Sleeping Sickness
Natalia Tiberti,Veerle Lejon,Alexandre Hainard,Bertrand Courtioux,Xavier Robin,Natacha Turck,Krister Kristensson,Enock Matovu,John Charles Enyaru,Dieudonné Mumba Ngoyi,Sanjeev Krishna,Sylvie Bisser,Joseph Mathu Ndung′u,Philippe Büscher,Jean-Charles Sanchez
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002088
Abstract: Background Post-therapeutic follow-up is essential to confirm cure and to detect early treatment failures in patients affected by sleeping sickness (HAT). Current methods, based on finding of parasites in blood and cerebrospinal fluid (CSF) and counting of white blood cells (WBC) in CSF, are imperfect. New markers for treatment outcome evaluation are needed. We hypothesized that alternative CSF markers, able to diagnose the meningo-encephalitic stage of the disease, could also be useful for the evaluation of treatment outcome. Methodology/Principal findings Cerebrospinal fluid from patients affected by Trypanosoma brucei gambiense HAT and followed for two years after treatment was investigated. The population comprised stage 2 (S2) patients either cured or experiencing treatment failure during the follow-up. IgM, neopterin, B2MG, MMP-9, ICAM-1, VCAM-1, CXCL10 and CXCL13 were first screened on a small number of HAT patients (n = 97). Neopterin and CXCL13 showed the highest accuracy in discriminating between S2 cured and S2 relapsed patients (AUC 99% and 94%, respectively). When verified on a larger cohort (n = 242), neopterin resulted to be the most efficient predictor of outcome. High levels of this molecule before treatment were already associated with an increased risk of treatment failure. At six months after treatment, neopterin discriminated between cured and relapsed S2 patients with 87% specificity and 92% sensitivity, showing a higher accuracy than white blood cell numbers. Conclusions/Significance In the present study, neopterin was highlighted as a useful marker for the evaluation of the post-therapeutic outcome in patients suffering from sleeping sickness. Detectable levels of this marker in the CSF have the potential to shorten the follow-up for HAT patients to six months after the end of the treatment.
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