SUNScholar - Browsing by Author "Kidd M."

Browsing by Author "Kidd M."

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A recently evolved sublineage of the Mycobacterium tuberculosis Beijing strain family is associated with an increased ability to spread and cause disease
(2007) Hanekom M.; Van Der Spuy G.D.; Streicher E.; Ndabambi S.L.; McEvoy C.R.E.; Kidd M.; Beyers N.; Victor T.C.; Van Helden P.D.; Warren R.M.
This study aimed to reconstruct the evolutionary history of Beijing strains of Mycobacterium tuberculosis and to test the hypothesis that evolution has influenced the ability of the Beijing strains within the different Beijing sublineages to spread and cause disease. A PCR-based method was used to analyze the genome structure of 40 different loci in 325 Beijing isolates collected from new and retreatment tuberculosis patients from an urban setting and 270 Beijing isolates collected from high-risk tuberculosis patients from a rural setting in the Western Cape, South Africa. The resulting data were subjected to phylogenetic analysis using the neighbor joining algorithm. Phylogenetic reconstructions were highly congruent with the "gold standard" phylogenetic tree based on synonymous single-nucleotide polymorphisms, thereby allowing a prediction of the order in which the evolutionary events had occurred. A total of seven independently evolving Beijing sublineages were identified. Analysis of epidemiological data in relation to the Beijing sublineage suggested an association between recent evolutionary change and frequency of occurrence in an urban population (P < 0.001) as well as in the rural population (P < 0.001). This concept was further supported by an association between more recently evolved Beijing strains and an increased ability to transmit and to cause disease (odds ratio, 5.82; 95% confidence interval, 3.13 to 10.82 [P < 0.001]). An association between Beijing sublineage and demographic and clinical parameters and drug resistance could not be demonstrated. From these data, we suggest that the pathogenic characteristics of Beijing strains are not conserved but rather that strains within individual lineages have evolved unique pathogenic characteristics. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
An index to measure the conservation attitudes of landowners towards Overberg Coastal Renosterveld, a critically endangered vegetation type in the Cape Floral Kingdom, South Africa
(2005) Winter S.J.; Esler K.J.; Kidd M.
The construction and validation of a user-friendly index to measure attitude of landowners towards conservation of Overberg Coastal Renosterveld (OCR), a critically endangered, distinctive grassy-shrubland in South Africa is reported. An iterative item reliability analysis was executed on questionnaire data from a random sample of 36 private landowners in the Overberg region of the Western Cape, using Spearman Rank Order correlations and Cronbach's Alpha. Results yielded an index with two dimensions and a Cronbach Alpha co-efficient of 0.67. Dimensions of conservation attitude towards renosterveld included: (i) landowners' perception of the benefit of Coastal Renosterveld; and (ii) willingness to conserve it. The mean conservation attitude score was 0.6 (±0.03), while minimum and maximum scores were 0.22 and 1.0, respectively, indicating that landowner attitudes were generally sympathetic towards OCR conservation. The following variables had significant associations with conservation attitude: (i) area of renosterveld; (ii) landowner environmental group membership status; (iii) presence of ecotourism activities on the property; and (iv) how long the property had been in the owner's family. Index scores can assist conservation practitioners to prioritise resources, on the assumption that high-scoring individuals are more likely to participate in conservation initiatives. © 2005 Elsevier Ltd. All rights reserved.
APRI: A simple bedside marker for advanced fibrosis that can avoid liver biopsy in patients with NAFLD/NASH
(2011) Kruger F.C.; Daniels C.R.; Kidd M.; Swart G.; Brundyn K.; van Rensburg C.; Kotze M.
Background. Non-alcoholic steatohepatitis (NASH) can lead to cirrhosis and hepatocellular carcinoma. The NASH fibrosis score (NFS) has proven to be a reliable, non-invasive marker for prediction of advanced fibrosis. Aspartate aminotransferase-to-platelet ratio index (APRI) is a simpler calculation than NFS, but has never been studied in patients with non-alcoholic fatty liver disease (NAFLD). Aim. To validate APRI as a non-invasive marker of liver fibrosis in subjects with NAFLD to be used in clinical practice. Design/Methods. The cohort consisted of 111 patients with histological diagnoses of NAFLD. The biopsy samples were staged and graded according to the NASH clinical research network (CRN) criteria. These were grouped into fatty liver disease (FLD), NASH, no/mild fibrosis, and advanced fibrosis. The sensitivity and specificity of APRI were compared with NFS and aspartate aminotransferase-to-alanine aminotransferase (AST/ALT) ratio. Results. The APRI was significantly higher in the advanced fibrosis group. The area under receiver operating characteristic (ROC) curve for APRI was 0.85 with an optimal cut-off of 0.98, giving a sensitivity of 75% and a specificity of 86%. The NFS was significantly lower in the advanced fibrosis group. The ROC for NFS gave an area under curve (AUC) of 0.77 and a cut-off value of -1.3 with a sensitivity of 76% and specificity of 69%. The positive predictive value for APRI was 54% as opposed to 34% for NFS. The negative predictive value was 93% for APRI and 94% for NFS. Conclusion. APRI compared favourably to NFS and was superior to AST/ALT for the prediction of advanced fibrosis. We therefore propose the use of APRI in a new algorithm for the detection of advanced fibrosis.
Case-control study of severe life threatening asthma (SLTA) in a developing community
(2006) Van Der Merwe L.; De Klerk A.; Kidd M.; Bardin P.G.; Van Schalkwyk E.M.
Background: Distinct risk factors for asthma death have not been identified in developing communities. This study was conducted to distinguish risk factors for severe life threatening asthma (SLTA), a proxy for asthma death, in a developing country. Methods: A case-control study was performed at a University Hospital serving developing communities in the Western Cape Province, South Africa, over the period October 1997 to April 2000. Thirty consecutive patients with SLTA admitted to the intensive care unit (ICU) were compared with 60 chronic asthmatic patients, without a history of SLTA, who had attended the hospital outpatient respiratory clinic over the same period. Results: The risk of SLTA in comparison with controls increased with female sex (odds ratio (OR) 3.3, 95% CI 1.2 to 9.6, p = 0.02), rural residence (OR 8.1, 95% CI 2.6 to 25.3, p = 0.0005), and absence of a formal income (OR 5.7, 95% CI 2 to 16.6, p = 0.002). Cases were more likely to have had more than one hospital admission in the previous year (OR 8, 95% CI 2.5 to 25.2, p = 0.0009) and more than one emergency room visit in the previous year (OR 4.4, 95% CI 1.19 to 16.4, p = 0.04). Patients with SLTA were less likely to use inhaled corticosteroids (OR 5.6, 95% CI 1.9 to 16.5, p = 0.003) and more likely to use inhaled fenoterol (OR 6, 95% CI 2.2 to 16.2, p = 0.0004). Patients with SLTA also had lower mean (SE) forced expiratory volume in 1 second (FEV1) measurements (66.9 (9.5)% predicted v 82.5 (4.0)% predicted; p = 0.03) and lower FEV 1/FVC ratios (60.7 (4.1)% predicted v69.6 (1.9)% predicted; p = 0.05) documented before the episode of SLTA. Conclusions: Risk factors for SLTA that are mainly analogous to those distinguished in other environments have been identified in a geographical area characterised by a third world socioeconomic context. Rural residence and poverty may increase the risk of SLTA.
Cross-Cultural Validation of a Measure of Felt Stigma in People with Intellectual Disabilities
(2011-10-13) Kock E.; Molteno C.; Mfiki N.; Kidd M.; Ali A.; King M.; Strydom A.
Background One trade-off for increased independence of adults with intellectual disabilities in developing countries is that they may find themselves more exposed to the negative perceptions held by the general population regarding the mentally ill and disabled. The aim of this study was to adapt and translate a tool to measure felt stigma in people with intellectual disabilities designed in the United Kingdom (UK) to make it culturally viable, and to determine its reliability and validity in the multi-ethnic and multilingual context of South Africa (SA) and to compare the item responses and factor structures of the tool between the UK and SA. Methods We translated the tool into local languages and refined it by conducting focus groups and pilot studies with professionals and adults with intellectual disabilities, after which test-retest reliability, factor analysis and internal consistency were calculated. Results Participants were from three different population groups: Afrikaans (n=71; 37%), English (n=67; 35%) and Xhosa (n=53; 28%), who had mild (n=106; 56%) or moderate intellectual disabilities (n=85; 44%). 98 (51%) were re-interviewed. The resulting international version of the perceived stigma measure consisted of 10 questions with good test-retest reliability (κ ranging from 0.41 to 0.59) and a similar factor structure to the UK version, despite including a different set of questions. Conclusions There is evidence for the validity of felt stigma ratings reported by adults with intellectual disabilities, despite different cultural and health service contexts. © 2011 Blackwell Publishing Ltd.
Developing a peak performance profile measurement for sport
(2011) Potgieter J.R.; Kidd M.
Epistaxis related to exercise-induced pulmonary haemorrhage in South African Thoroughbreds
(2003) Weideman H.; Schoeman S.J.; Jordaan G.F.; Kidd M.
This study investigated if environmental factors had an effect on the incidence of epistaxis related to exercise-induced pulmonary haemorrhage (EIPH) among racehorses in southern Africa. Data covering the period 1986-2001 and involving 778 532 race runs were analysed. This included the following information: date of race, age, sex, name of breeder, trainer, distance, jockey, state of going, weight carried, racing centre and altitude. Veterinarians employed by the Jockey Club suspended officially entered horses that presented with epistaxis (frank bleeding from the nostrils) after racing. On-course endoscopy is not performed as a standard practice at any southern African racetrack. Epistaxis was identified in 1287 horses (0.165 %). More horses presented with EIPH-related epistaxis (a) at sea level, (b) from May to October, (c) when older (>3 years), (d) after 1995, (e) on Fridays and Sundays, and (f) more in geldings than in mares or entire males. No association could be established between epistaxis and breeder, trainer, distance run, jockey, state of going and weight carried. It is concluded that the frequency of EIPH-related epistaxis is associated with altitude, winter and spring, sex and age. It is suggested that racing at lower altitudes may increase the probability of exercise-induced pulmonary haemorrhage.
Ethnicity and characteristics of Hodgkin lymphoma in children
(2009) Stefan D.C.; Stones D.; Dippenaar A.; Kidd M.
Aim. To identify ethnic group differences in the prognostic of Hodgkin lymphoma (HL) in South African children. Patients and Methods. In order to create a larger database, cases were pooled from two South African hospitals: Tygerberg in the Western Cape and Bloemfontein Academic Complex in Free State. Self-assigned ethnicity was used to allocate the children to the following groups: black, white, and colored (historical descendants of couples of distinct ethnicity, the "Cape colored" are the largest population group in Western Cape). Retrospective data over 21 years were obtained from the tumor registry. Age at presentation, sex, ethnic group, stage, histological type, treatment protocol, event-free survival interval, and mortality were analyzed. The statistical significance of the findings was tested using the chi-square, Mann-Whitney U, and Kruskal-Wallis tests, as indicated. Results. The study population of 138 comprised 78 black (56.5%), 38 colored (27.5%), and 22 white (16%) children under 15 years of age. There was a 3:1 predominance of the male gender. The median age at diagnosis was 8 years 11 months. Black patients presented at the youngest age (median 103 months), whereas white patients were the oldest at presentation (median age 133 months; P = 0.04). Forty-five percent of all patients were seen in stage 2. Black and colored patients presented with significantly more advanced stage disease (P = 0.04) than whites. B symptoms were evenly distributed among ethnic groups; they increased the mortality ratio from 10% to 33% (P = 0.0019). Histologically, mixed cellularity was seen in 50% of the black children, while nodular sclerosis was found in 50% of whites. The overall survival rate is 79%, with 68% in whites, 84% in patients of mixed ethnicity, and 79% in blacks (P = 0.35). Conclusions. White children had the worst HL prognosis in this series, in spite of a less advanced stage at presentation. © 2008 Wiley-Liss, Inc.
Evaluation of near infrared spectra for the prediction of post harvest quality in canning peaches
(2009) Manley M.; Joubert E.; Myburgh L.; Lotz E.; Kidd M.
Huge production losses occur because of deterioration of quality of clingstone peaches during cold storage, rendering the fruit unsuitable for canning. Near infrared (NIR) spectra recorded from intact clingstone peaches were evaluated to predict post harvest quality of these peaches. The NIR spectra were recorded, before storage, on the fresh peaches while the subjective post-storage quality, fruit firmness and diameter (reference data) were determined after either three-(2002 season) or two-week (2003 season) cold storage periods at-0.5°C. Poor post-storage quality was indicated by softening of the flesh, loosening of the skin and adhesion of the flesh to the stone after destoning. Soft independent modeling by class analogy (SIMCA) gave correct total classifications of between 53 and 60% in comparison to the 57 to 65% obtained by multivariate adaptive regression splines (MARS). However, when predicting only poor post-storage quality, correct classfication rates of between 60 and 80% were obtained using MARS. Using classification trees, the fruit were classified into good and poor post-storage quality classes according to fruit firmness and diameter. Only reasonable results were obtained due to the poor relationship between the NIR spectra and firmness measurements.
Evaluation of the compositional and functional quality of South African triticale (x Triticosecale Wittmack) cultivars
(2011) Manley M.; Snyders F.; McGoverin C.; Fox G.; Muller M.; Kidd M.; Botes W.
The baking potential of South African bred triticale (x Triticosecale spp. Wittmack ex A. Camus 1927) cultivars, and the effect of cultivar and environment on baking potential parameters had not previously been studied. At present South African triticale cultivars are used for animal feed as grazing, hay or silage. Seven cultivars harvested over two years from eight localities in the Western Cape region of South Africa were used to examine the baking potential parameters falling number, SDS sedimentation, ash content, particle size index, total protein content and 1000-kernel mass. The quality of the South African bred cultivars compared well with data from cultivars grown in other countries. The triticale cultivars studied here generally had higher ash contents, lower falling numbers and SDS sedimentation values than the bread wheat standard. Significant differences (P<0.05) were observed between cultivars and between localities in each year's harvest, illustrating the effect of genetic as well as environmental factors on the quality of the grain produced. Interactions between cultivars and localities were found to be significant (P<0.05) in all cases.
Evaluation of the implementation of the vitamin A supplementation programme in the Boland/Overberg region of the Western Cape Province
(2007) du Plessis L.M.; Najaar B.; Koornhof H.E.; Labadarios D.; Petersen L.; Hendricks M.; Kidd M.
Objective. To assess the implementation of the vitamin A supplementation programme in primary health care (PHC) clinics in a rural area of the Western Cape Province. Material and methods. A study was conducted at 14 randomly selected PHC clinics. All children aged 6 - 60 months attending on the day of surveying with their mothers/caregivers were selected by purposive sampling, after they had been seen by a PHC nurse in the clinic. A structured exit interview was conducted with the mother/caregiver of each child. The information from 56 such interviews could be utilised for data analysis. The manager of each clinic was also interviewed. Results. Seventy-seven per cent of the study population (N=40) was eligible for high-dose vitamin A supplementation on the day of the study, based on the criteria of the vitamin A supplementation protocol. However, 25% of these children (N=10) did not receive vitamin A, even though there was an indication to administer it. Only 39% of mothers (N=22) reported that they were aware of the supplementation programme. All the health facility managers of the clinics had received training in the programme. Staffing problems and stock shortages appeared to play a role in inadequate implementation of the programme at some clinics. In addition, health facility managers reported that many children failed to receive their vitamin A dose because parents did not bring them regularly to clinics. Conclusions. The vitamin A supplementation programme appears to be reasonably successfully implemented in the Boland/Overberg region. Informing mothers about the importance of vitamin A supplementation and regular clinic attendance, as well as improving the availability of human and material resources and logistic support at PHC facilities, may further enhance the implementation and success of the programme.
Health Claims on the Benefits of Moderate Alcohol Consumption in Relation to Genetic Profiles
(2011) van Velden D.P.; Kotze M.J.; Blackhurst D.M.; Marnewick J.L.; Kidd M.
A total of 43 individuals were included in a study of genetic and environmental factors associated with cardiovascular disease; seven subjects (16%) were diagnosed with the metabolic syndrome. A statistically significant association was observed between the E2 allele of the apolipoprotein E (Apo E) polymorphism and an increasing number of metabolic syndrome features (p = 0.03). Clinical and biochemical abnormalities identified could be ascribed to the combined effects of unfavorable genotypes and environmental factors known to interact with the Apo E gene. Excessive alcohol intake, high-calorie diets and smoking should be restricted in individuals with the Apo E2 and/or E4 alleles, which are associated with a significantly increased risk of cardiovascular disease. © 2011 Copyright Taylor and Francis Group, LLC.
Improvement in mycobacterial yield and reduced time to detection in pediatric samples by use of a nutrient broth growth supplement
(2009) Brittle W.; Marais B.J.; Hesseling A.C.; Schaaf H.S.; Kidd M.; Wasserman E.; Botha T.
There is an urgent need to improve the methods used for the bacteriological diagnosis of childhood mycobacterial disease. This study compared the mycobacterial yields and the times to detection (in days) of mycobacteria in pediatric clinical specimens by using Mycobacterial Growth Indicator Tubes (MGITs) and solid Löwenstein-Jensen (LJ) slants with and without a nutrient broth supplement. A total of 801 specimens from 493 patients were processed: 82.8% were gastric aspirate specimens, 15.6% were sputum specimens, and 1.6% were fine-needle-aspiration biopsy specimens. The mycobacterial yield obtained with MGITs (with and without nutrient broth) was 11.0%, and that obtained with LJ slants was 1.6% (P < 0.001). Of the 88 positive cultures, 62 were detected in MGITs and 73 were detected in MGITs supplemented with nutrient broth (P = 0.11). The mean time to detection in MGITs (without nutrient broth) was 18.5 days, whereas it was 12.4 days in MGITs with nutrient broth (P < 0.001). Supplementation of standard MGITs improved the mycobacterial yield and significantly reduced the time to detection of mycobacteria in pediatric samples. Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Investigation of telomere length and psychological stress in rape victims
(2011) Malan S.; Hemmings, Sian M. J.; Kidd M.; Martin L.; Seedat S.
Lymphocyte measures in treatment-naïve 13-15-year old adolescents with alcohol use disorders
(2011) Naude C.E.; Bouic P.; Senekal M.; Kidd M.; Ferrett H.L.; Fein G.; Carey P.D.
Many adolescents have chronic exposure to hazardous levels of alcohol. This is likely to be a significant predictor of health outcomes, including those related to immunity. We assessed substance use and biochemical immunological parameters in heavy drinking adolescents (meeting DSM-IV criteria for alcohol dependence) and light/nondrinking control adolescents in Cape Town. Lifetime alcohol dose, measured in standard units of alcohol, was orders of magnitude higher in alcohol-dependent (AD) participants than controls. All adolescent AD had a "weekends-only" style of alcohol consumption. The AD group was chosen to represent relatively "pure" AD, with minimal other drug use and no psychiatric diagnoses. With these narrow parameters in place, we found that AD adolescents were lymphopenic compared with controls, with significantly lower mean numbers of absolute circulating CD3+, CD4+, and CD8+ T-lymphocytes. On conclusion, we found that adolescent AD individuals with excessive alcohol intake, in a weekend binge-drinking style but without comorbid drug or psychiatric disorders, may be at increased risk of lymphopenia. This alcohol misuse may increase infectious disease susceptibility (including TB and HIV) by reducing immune system capabilities. Complex interactions of alcohol with other documented high-risk activities may further compound health risks. © 2011 Elsevier Ltd.
Meat quality of kudu (Tragelaphus strepsiceros) and impala (Aepyceros melampus): Carcass yield, physical quality and chemical composition of kudu and impala Longissimus dorsi muscle as affected by gender and age
(2009) Hoffman L.C.; Mostert A.C.; Kidd M.; Laubscher L.L.
The meat quality of kudu and impala was compared. Live weight and carcass weight differed between species, genders and age groups. Impala had the highest dressing percentage while kudu had the highest live weight and carcass weight. Kudu had the lowest fat content while female animals had a higher fat and myoglobin content than males. Sub-adults had a higher ash content than adults. Species, gender and age had no effect of pH, drip loss, cooking loss or tenderness although kudu had higher L*, a*, b* and chroma values than impala. Impala sub-adults had significantly higher insoluble collagen, soluble collagen, total collagen and hydroxyproline content than kudu sub-adults. Kudu had the highest potassium levels while impala had the highest phosphorus levels. Potassium, sodium, iron and copper levels also differed between species. © 2009 Elsevier Ltd. All rights reserved.
Pediatric and adolescent imported malaria in Cape Town.
(2009) Gray T.C.; Cooke M.L.; Rabie H.; Kidd M.; Cotton M.F.
We reviewed 42 cases of pediatric and adolescent imported malaria in Cape Town. Patients were predominantly new and returned immigrants from other African countries. Rapid diagnosis occurred in most cases. Eleven of 42 (26%) had severe malaria. Management issues included delay to and inappropriate treatment, inadequate monitoring for hypoglycemia, and under notification to health authorities.
Premasticating food for weaning african infants: A possible vehicle for transmission of HIV
(2011) Maritz E.R.; Kidd M.; Cotton M.F.
BACKGROUND: Although premastication of food for weaning infants might have nutritional benefit, it is also associated with transmission of pathogens. We investigated premastication practices in Cape Town, South Africa, in lower socioeconomic status caregivers of infants below 2 years of age. METHODS: A previously reported questionnaire was adapted for South African conditions. A convenience sample of infant caregivers was captured at public maternal/pediatric and HIV outpatient clinics and home visits. RESULTS: We interviewed 154 caregivers, 92% of whom were the biological mothers (median age: 29). Of these, 70% were black, and 29% were colored. There were 106 (69%) caregivers who practiced premastication. The median age of infants who received premasticated food was 6 (interquartile range: 4-6) months. Forty-six (43%) infants were teething, and 44 (42%) had oral mucosal lesions while receiving premasticated food. Fifty-five (52%) caregivers reported an oral condition, mostly bleeding gums, mouth sores, and thrush, and 41 (39%) caregivers reported blood in the food. Premasticating caregivers had a significantly lower educational level than those caregivers who did not engage in this practice. Premastication practices were cultural (40%), habit (20%), and on mother's advice (75%). Reasons for premastication were to pretaste (68%), encourage eating (61%), estimate food temperature (85%), and homogenize food (60%). CONCLUSIONS: Counselors and caregivers should be aware of the adverse effects of premastication. Education should include advice to avoid premastication and to seek health advice for oral conditions in the caregiver and child. More studies are needed to better define the extent and risks of premastication, including its possible role in increasing HIV-1 transmission. Copyright © 2011 by the American Academy of Pediatrics.
Remission in first-episode psychosis: Predictor variables and symptom improvement patterns
(2006) Emsley R.; Oosthuizen P.P.; Kidd M.; Koen L.; Niehaus D.J.H.; Turner H.J.
Background: Previous attempts to identify clinically useful predictors of treatment outcome in schizophrenia have been hampered by methodological inconsistencies, including a lack of standardized outcome measures. Recently proposed operationally defined criteria for remission provide an opportunity to readdress this topic. Method: We applied the remission criteria to a sample of 57 subjects with first-episode psychosis (DSM-IV schizophrenia, schizoaffective disorder, or schizophreniform disorder), treated according to a fixed protocol in a prospective study. Subjects were recruited between April 1999 and January 2000 and were followed for 2 years. Various demographic, baseline clinical, and early-response variables were subjected to discriminant analysis for their ability to predict remission or nonremission. We also assessed the symptom improvement patterns over time and compared endpoint psychopathology in the remitters and nonremitters. Results: A model incorporating neurologic soft signs, 6-week treatment response, duration of untreated psychosis, marital status, and Positive and Negative Syndrome Scale excited factor baseline score was able to correctly predict 89% of the remitters and 86% of the nonremitters. Symptom reduction at 6 weeks, including core psychotic symptoms, was significant in both groups (remitters, p < .0001; nonremitters, p < .0001), although reduction was substantially greater in the remission group (p = .004). Thereafter, the remission group continued to improve (p < .01), while the nonremitting group failed to do so (p = .55). Considerable overlap of endpoint symptoms was observed, and depressive symptom scores were similar in remitters and nonremitters. Conclusion: A combination of demographic, baseline clinical, and acute treatment response variables may accurately predict treatment outcome. Persistent noncore psychotic symptoms in subjects meeting proposed remission criteria require further investigation.
Selective attention to fearful faces during pregnancy
(2012-01-18) Roos A.; Lochner C.; Kidd M.; van Honk J.; Vythilingum B.; Stein D.J.

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