25 research outputs found
The Th1/Th2/Th17 cytokine profile of HIV-infected individuals : a multivariate cytokinomics approach
HIV infection causes the dysregulation of cytokine production. A cytokinomics approach
employing cytometric bead array (CBA) technology, flow cytometry and multivariate analysis
was applied to the investigation of HIV-induced T helper cell type 1 (Th1), Th2 and Th17
cytokine changes in the serum of treatment naive individuals. Stepwise linear discriminant
analysis (LDA) and logistic regression identified interleukin (IL)-6 to be discriminatory for HIV
infection with 74.6 and 71.2 % of the cases correctly classified. Analysis of variance
(ANOVA) confirmed IL-6 and IL-10 concentrations to be significantly (p= 0.001 and p=0.025)
different between the groups. A scatter plot of the log IL-6 and IL-10 concentrations for the
groups largely overlapped, with improved differentiation where patients were advancing to
the acquired immunodeficiency syndrome (AIDS). IL-17A levels were higher than other
cytokines but did not significantly distinguish the groups suggesting that the HIV- and HIV+
individuals had similar immune profiles. This possibility was supported by other clinical
indicators. Taken together, the measured cytokines (IL-6, 10 and 17) have potential
prognostic value.This work was supported by the National Research Foundation, Technology
Innovation Agency, Medical Research Council and the Faculty of Natural and Agricultural
Sciences at the University of Pretoria.http://www.journals.elsevier.com/cytokinehb201
The application of imaging technologies in the detection of trace evidence in forensic medical investigation
In a country notorious for violent crime, it seems that South African medico-legal laboratories make
minimal application of technology in the death investigation process and little attention is given to trace
evidence. Non-destructive, non-invasive, portable and cost-effective tools are required. This study was
conducted at the Pretoria Medico-Legal Laboratory. The surface area of the bodies and clothing of victims
of fatal interpersonal violence were examined using a torch, magnifying lamp, portable digital
microscope and alternate light source to gauge their potential for trace evidence detection. Most studies
apply these and similar tools to inert surfaces, with few focusing on their application to human skin.
There was a statistically significant difference in the detection of many of the evidence types between the
naked-eye observation of the pathologists and the technologies. The different imaging technologies were
compared as to their cost, evidence detection ability and ease of use. The most common evidence types
discovered on the bodies and clothing of victims of fatal interpersonal violence, as well as the propensity
of each tool to detect these, was evaluated in order to devise the best option for incorporation into the
Pretoria Medico-Legal Laboratory routine. The digital microscope performed best overall followed by the
magnifying lamp, torch and the Polilight1. This study aimed to justify the investment of more time,
effort and funding into trace evidence recovery in the South African mortuary environment.This work has not been previously published, except in the form of an academic
dissertation and was presented at the 2nd National Forensic Services Conference in
South Africa.Research Fund of the Forensic Medicine Department
at the University of Pretoria.http://www.elsevier.com/locate/forsciinthb201
Mid-ATR-FTIR spectroscopic profiling of HIV/AIDS sera for novel systems diagnostics in global health
Please read abstract in the article.The Technology Innovation Agency (TIA) and the University of
Pretoria.http://www.liebertonline.com/loi/omiam201
Predicting the influence of multiple components on microbial inhibition using a logistic response model - a novel approach
BACKGROUND: There are several synergistic methods available. However, there is a vast discrepancy in the
interpretation of the synergistic results. Also, these synergistic methods do not assess the influence the tested
components (drugs, plant and natural extracts), have upon one another, when more than two components are
combined.
METHODS: A modified checkerboard method was used to evaluate the synergistic potential of Heteropyxis natalensis,
Melaleuca alternifolia, Mentha piperita and the green tea extract known as TEAVIGOâ„¢. The synergistic combination
was tested against the oral pathogens, Streptococcus mutans, Prevotella intermedia and Candida albicans. Inhibition
data obtained from the checkerboard method, in the form of binary code, was used to compute a logistic response
model with statistically significant results (p < 0.05). This information was used to construct a novel predictive
inhibition model.
RESULTS: Based on the predictive inhibition model for each microorganism, the oral pathogens tested were
successfully inhibited (at 100% probability) with their respective synergistic combinations. The predictive inhibition
model also provided information on the influence that different components have upon one another, and on the
overall probability of inhibition.
CONCLUSIONS: Using the logistic response model negates the need to ‘calculate’ synergism as the results are
statistically significant. In successfully determining the influence multiple components have upon one another and
their effect on microbial inhibition, a novel predictive model was established. This ability to screen multiple
components may have far reaching effects in ethnopharmacology, agriculture and pharmaceuticals.The University of Pretoria holds a provisional South African patent (ZA2013/
06534) relating to the content of the manuscript. No financial benefits have
been received by the authors.The University of Pretoria and the Gen Foundation.http://www.biomedcentral.com/bmccomplementalternmedam201
UPLC-MS metabonomics reveals perturbed metabolites in HIV-infected sera
Immune responses to infection by the human immunodeficiency virus (HIV) and the use of highly active
antiretroviral therapy (HAART) to treat HIV infection, contributes to metabolic irregularities in the host.
Current methods for the extraction and identification of metabolites in biofluids generally make use of
laborious, time-consuming protocols. Here, 96-well Ostroâ„¢ plates and filtration under positive pressure was
used to facilitate the simultaneous, reproducible extraction of metabolites from multiple serum samples which
were then analyzed by ultra-performance liquid chromatography mass spectrometry (UPLC-MS). The easy to
use solid phase extraction (SPE) protocol eliminated numerous potential contaminants while the UPLC-MS
detection of metabolites produced visibly different chromatograms for HIV negative (n=16), HIV+ (n=13) and
HIV+HAART+ (n=15) serum samples. Linear discriminant analysis (LDA) amplified these differences,
classified the groups with 100% accuracy and identified biomarkers explaining the greatest variances between
the groups. The 21 metabolites altered by HIV and/or HAART primarily represented those linked to lipid and
energy pathways which is where known metabolic changes associated with HIV infection occur. This work
demonstrated for the first time that OstroTM plates and UPLC-MS metabonomics was able to successfully
identify distinct differences between the experimental groups and detected metabolites related to HAART and
other drugs used in the treatment of HIV-associated conditions. The findings of this approach suggests a
possible role for this methodology in disease prognosis as well as in the monitoring of treatment success or
failure and linking treatment to metabolic complications.The Medical Research Council (MRC), Technology Innovation Agency (TIA) and the National Research Foundation (NRF) of South Africa.http://benthamscience.com/journal/index.php?journalID=cmbhb2017BiochemistryStatistic
Back-carrying in children is related to lower limb development
Back-carrying of children is a culturally accepted method of transport and safekeeping of
babies in many cultures. Developmental consequences related to back-carrying practices have not
been directly investigated. This study determined the relationship between frontal and transverse
plane lower limb (LL) development, and back-carrying practices, in black Setswana-speaking children.
In 691 2- to 9-year-old Setswana-speaking children, the tibiofemoral angle, intermalleolar distance,
femoral anteversion angle (AVA) and tibial torsion angle (TTA), were measured to determine LL
development. Back-carrying practices were recorded with a questionnaire and Classification and
Regression Tree (CART) was used for the analyses. Significant (p < 0.001) relationships, between
back-carrying practices and LL development, were discovered. Statistically significant greater genu
valgum (F(5, 690) = 7.2, p < 0.001), greater internal TTAs (F(9, 684) = 17.8, p < 0.001), and smaller
AVAs (F(13, 685) = 5.1, p < 0.001) were observed in children back-carried more frequently than
children back-carried less frequently. There are relationships between back-carrying practices and
LL development in both the frontal and transverse plane. However, the genu valgum, internal TTA
and smaller AVA noted in more frequently back-carried children is still within normal limits, thus
no educational intervention in back-carrying methods or durations is required. Further research
should determine the exact back-carrying practice factors (age until which the child is back-carried)
impacting lower limb development the greatest.This is a part of the Ph.D. thesis of Mariaan van Aswegen at North-West University,
Potchefstroom 2520, South Africa.https://www.mdpi.com/journal/childrendm2022Consumer ScienceFood Scienc
Biotransformation profiles from a cohort of chronic fatigue women in response to a hepatic detoxification challenge
Chronic fatigue, in its various manifestations, frequently co-occur with pain, sleep disturbances
and depression and is a non-communicable condition which is rapidly becoming
endemic worldwide. However, it is handicapped by a lack of objective definitions and diagnostic
measures. This has prompted the World Health Organization to develop an international
instrument whose intended purpose is to improve quality of life (QOL), with energy
and fatigue as one domain of focus. To complement this objective, the interface between
detoxification, the exposome, and xenobiotic-sensing by nuclear receptors that mediate
induction of biotransformation-linked genes, is stimulating renewed attention to a rational
development of strategies to identify the metabolic profiles in complex multifactorial conditions
like fatigue. Here we present results from a seven-year study of a cohort of 576 female
patients suffering from low to high levels of chronic fatigue, in which phase I and phase II biotransformation
was assessed. The biotransformation profiles used were based on hepatic
detoxification challenge tests through oral caffeine, acetaminophen and acetylsalicylic acid
ingestion coupled with oxidative stress analyses. The interventions indicated normal phase I
but increased phase II glucuronidation and glycination conjugation. Complementarity was
indicated between a fatigue scale, medical symptoms and associated energy-related
parameters by application of Chi-square Automatic Interaction Detector (CHAID) analysis.
The presented study provides a cluster of data from which we propose that multidisciplinary
inputs from the combination of a fatigue scale, medical symptoms and biotransformation
profiles provide the rationale for the development of a comprehensive laboratory instrument
for improved diagnostics and personalized interventions in patients with chronic fatigue with a view to improving their QOL.Research funding for the analytical and
computational aspects of the project was provided
by the Technological Innovation Agency (TIA) of
the Department of Science and Technology of
South Africa.http://www.plosone.orgam2019Consumer Scienc
Analysis of wear-related failures in long-term follow-up of crosslinked polyethylene hip sockets
The publication of our long-term hip replacement follow-up study computer analysis has clearly demonstrated the
association between polyethylene (polyethylene/UHMWPE) wear on the one hand and pain, interface widening
and osteolysis on the other1. From a total of 97 cases, seven had true failure and needed ultimate revision. These
seven cases formed the nucleus of the current study (Group 1). The course of events could then be analysed in
great detail, and compared with the other 90 cases (Groups 2, 3, and 4).
The purpose of this paper was to confirm the role of polyethylene wear (the independent variable) in the limitation
of longevity of the implant; furthermore to identify the cut-off point of wear that is considered acceptable.
At the same time quantification of P, I, O (pain, interface widening and osteolysis) was studied (the dependent
variables). Once again, computer analysis provided us with detailed values that would constitute the cut-off points
for acceptance.
These findings then enabled us to categorise the 97 cases into four groups. Of special interest was Group 2:
‘impending failure’. Even though none of the nine cases in Group 2 were revised, this study clearly demonstrated
that they should be classified as failures and managed accordingly.
In this study some other controversial issues were addressed: the degree of wear proved important as opposed
to the tempo, which was not! Equally unimpressive were the patients’ age, activity and body mass, which according
to digital analysis had little effect on implant longevity.http://www.charpublications.co.za/C_JournalsORTH.as
Long-term evaluation of polyethylene wear in total hip replacement : a statistical analysis of the association between the degree of wear versus pain, interface change, osteopysis and implant failure
With over 3.5 decades dedicated exclusively to total joint replacement, our arthroplasty unit has repeatedly identified
and reported a clear correlation between cup wear on the one hand, and pain, interface widening and osteolytic
failure on the other1. However, in view of the fact that this statement has sparked some controversy, clarification
of this correlation became imperative, particularly in view of important clinical consequences.
Materials and methods were provided by a potentially long-lasting gamma crosslinked cup. The arthroplasty follow-
up ranged from 10-33 years. Objective clinical, radiographic and pathological evaluations were backed by
computer analysis through the Department of Statistics at the University of Pretoria.
We are able to conclude that the statistical correlation between wear, on the one hand, versus pain, interface
effects and osteolysis on the other, was no coincidence but instead proved to be clearly conclusive. Of great
importance is the fact that this study allowed us to set new objective criteria for true failure as well as impending
failure, thus guiding us towards sensible decision-making in terms of revision surgery in these complex
issues. Cup wear was thus clearly identified as the overwhelming leading variable in long-term prognosis in this
type of total hip replacement.http://www.charpublications.co.za/C_JournalsORTH.as
A combined chemometric and quantitative NMR analysis of HIV/AIDS serum discloses metabolic alterations associated with disease status
Individuals infected with the human immunodeficiency virus (HIV) often suffer from concomitant metabolic
complications. Treatment with antiretroviral therapy has also been shown to alter the metabolism of patients.
Although chemometric analysis of nuclear magnetic resonance (NMR) spectra of human sera can distinguish
normal sera (HIVneg) from HIV-infected sera (HIVpos) and sera from HIV-infected patients on antiretroviral
therapy (ART), quantitative analysis of the discriminating metabolites and their relationship to disease status has
yet to be determined. The objectives of the study were to analyze NMR spectra of HIVneg, HIVpos, and ART
serum samples with a combination of chemometric and quantitative methods and to compare the NMR data
with disease status as measured by viral load and CD4 count. High-resolution magic angle spinning (HRMAS)
NMR spectroscopy was performed on HIVneg (N = 10), HIVpos (N = 10), and ART (N = 10) serum samples.
Chemometric linear discriminant analysis classified the three groups of spectra with 100% accuracy.
Concentrations of 12 metabolites were determined with a semi-parametric metabolite quantification method
named high-resolution quantum estimation (HR-QUEST). CD4 count was directly associated with alanine (p =
0.008), and inversely correlated with both glutamine (p = 0.017) and glucose (p = 0.022) concentrations. A
multivariate linear model using alanine, glutamine and glucose as covariates demonstrated an association with
CD4 count (p = 0.038). The combined chemometric and quantitative analysis of the data disclosed previously
unknown associations between specific metabolites and disease status. The observed associations with CD4
count are consistent with metabolic disorders that are commonly seen in HIV-infected patients.http://www.rsc.org/molecularbiosystemsam201