Chemical Pathology

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Browsing Chemical Pathology by browse.metadata.advisor "Matsha, Tandi"

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    The effect of fructosamine 3 kinase (FN3K) genotypes on the glycation gap in type 2 diabetic and non-diabetic mixed ancestry population of South Africa
    (Stellenbosch : Stellenbosch University, 2018-12) Motshwari, Dipuo Dephney; Erasmus, Rajiv T.; Zemlin, Annalise E.; Matsha, Tandi; Stellenbosch University. Faculty of Medicine and Health Science. Dept. of Pathology. Chemical Pathology.
    ENGLISH ABSTRACT: Introduction In2017 the International Diabetes Federation (IDF) reported that approximately 425 million adults aged 20-79 years were estimated to have diabetes mellitus (DM) worldwide. The nonenzymatic glycation reactions of proteins such as haemoglobin have been associated with the development of diabetic related complications. These reactions were believed to be irreversible until the discovery of a protein repair enzyme fructosamine 3 kinase (FN3K). This enzyme deglycates glycated haemoglobin (HbA1c) in erythrocytes and other glycated proteins in other tissues. Animal model studies found that the activity of this enzyme varies between individuals leading to differences in HbA1c levels. This results in discrepancies between HbA1c and other glycaemic measures which is termed the glycation gap. The glycation gap is consistent over time within individuals and is associated with diabetic complications. Genetic variants in the FN3K gene have been associated with altered enzyme activity. Therefore, the aim of this study was to examine the role of FN3K genotypes on the glycation gap Methods A total of 1412 subjects (925 normal, 216 pre-diabetic and 271 type 2 diabetics), with 339 males and 1073 females aged ≥ 20 years of mixed ancestry descent, residing in Bellville South, South Africa were included in this study. The diabetics were diagnosed using the oral glucose tolerance test. The glycation gap was determined according to a formula: Glycation gap= HbA1c - FHbA1c, (FHbA1c = {[(fructosamine- mean fructosamine)/SD fructosamine] X SD HbA1c} + mean HbA1c). DNA was extracted from whole blood using the salt extraction method. FN3K single nucleotide polymorphisms (SNPs) were genotyped with the Applied Biosystems™ QuantStudio™ 7 Flex Real-Time PCR System 96 well fast from Thermo Fisher Scientific. HbA1c was measured using HPLC (Biorad Variant Turbo) and fructosamine was measured using a colorimetric test nitro-blue-tetrazolium (NBT). Results SNP c. -232A/T deviated from Hardy Weinberg Equilibrium (HWE) and was left out for the rest of the statistical analysis. The polymorphism G900C followed the Hardy-Weinberg Equilibrium and was therefore studied. The genotype frequencies for SNP G900C in the glycaemic sub-groups were as follows, GG: 45.9 %, GC: 43.7 %, CC: 10.4 % in normal subjects; GG: 48.6 %, GC: 41.7 %, CC: 9.7% in pre-diabetics and GG: 41.7 %, GC: 46.5 %, CC: 11.8 % in diabetics, and they followed the Hardy-Weinberg equilibrium. There were no significant differences in the SNP G900C genotype frequencies between the glycaemic subgroups. The glycation gap significantly decreased across the GG, GC and CC genotype variants in males, mean ± SD were -0.13±0.86, -0.25±0.72 and -0.80±1.04 respectively, (P=0.0239). However the difference was not observed in females. Moreover the glycation gap showed a positive correlation with non glycaemic factors including body mass index (BMI) (r=0.3694, p<0.0001), waist circumference (waistC) (r=0.3749, p<0.0001), hip circumference (hipC) (r0.3151, p<0.0001), triglycerides (r=0.2540, p<0.0001) and a negative correlation with high density lipoprotein cholesterol (HDL-Chol) (r=-0.2031, p<0.0001). Conclusion In conclusion the present study found that the glycation gap might be influenced by genetic In conclusion the present study found that the glycation gap might be influenced by genetic active mechanisms in the intracellular erythrocyte compartment. Identification of the G900C polymorphism in an early stage of diabetes could be useful especially in therapeutic decisions and prediction of improved prognosis. However, there are other confounding factors influencing the glycation gap and future studies are required to confirm these findings.
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    Molecular investigation of genetic and environmental factors contributing to obesity in adolescent learners residing in the semi-urban/rural areas of the Western Cape Province, South Africa
    (Stellenbosch : Stellenbosch University, 2012-12) Yako, Yandiswa Yolanda; Erasmus, Rajiv T.; Matsha, Tandi; Janse van Rensburg, Susan; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology. Chemical Pathology.
    ENGLISH ABSTRACT: Background/Aims: Obesity has increased rapidly in South African children and adolescents with significant variability observed among racial groups. Genes that regulate appetite have been studied in different populations worldwide, but their role in obesity among South African adolescents is unknown. The present study aimed at investigating the role of these genes, and their combined effect with physical activity in the development of obesity among South African adolescents. Methods: A total of 1564 South African school learners of Caucasian (n= 146), Mixed Ancestry (n= 872) and Black African (n= 537) ethnic groups were recruited for a research project that aimed to elucidate diabetes and the metabolic syndrome in children and adolescents attending schools in periurban areas of the Western Cape. The present case-control study included 227 obese-overweight (115 Black Africans and 112 Mixed Ancestry), and 204 normal weight (94 Black Africans and 110 Mixed Ancestry) adolescents learners. The learners were genotyped for nine polymorphisms (LEP: 19G>A, Lys36Arg, Val94Met; LEPR: Lys109Arg; Gln223Arg, Lys656Asn; CART: c.160-33G>A, c.499delA, and c.517A>G; GHRL: Leu72Met; and MC3R: Thr6Lys, Val81Ile) using allele-specific restriction enzyme analysis and automated sequencing. Genotype and haplotype associations with anthropometric variables such as body mass index (BMI), waist, hip, and mid-upper-arm circumferences (WC, HC, MUAC), and metabolic traits (fasting blood glucose, high density lipoproteincholesterol, total cholesterol), and blood pressure were further conducted. Furthermore, the type and frequency of physical activity was assessed by means of structured questionnaires; and its effect on obesity-related variables investigated in learners that were genotyped for the MC3R Thr6Lys and Val81Ile polymorphisms. Results: In a stepwise backward logistic regression analysis (containing age, gender, and LEP, LEPR, CART and GHRL polymorphisms), CART c.517A>G was independently significantly associated with obesity (OR= 5.98; 95%CI= 2.02, 21.27). CART c.517G carriers had higher MUAC (b coefficient= 1.88; 95%CI= 0.31, 3.44) while the LEPR 109Arg allele was significantly associated with decreased BMI (b coefficient = -2.36; 95%CI= -4.24, -0.47), WC (b coefficient = -5.66; 95%CI= -9.89, -1.44) and MUAC (b coefficient = -1.61; 95%CI= -3.00, -0.22); after adjusting for age, gender, and ethnicity. The haplotype containing the three LEP polymorphisms (A-A-A compared to the reference G-A-G haplotype) increased BMI (p= 0.0155), MUAC (p= 0.0146), and HC (p= 0.0128). The minor alleles of the MC3R polymorphisms decreased BMI, HC, WC, MUAC and TC; whilst only the Thr6Lys was associated with systolic and diastolic blood pressure (p= 0.0047 and 0.0027, respectively) in Mixed Ancestry learners. Doing house chores was associated with lower total cholesterol, independently and in the presence of the 81Ile allele (b coefficient = -0.355; 95%CI= 0.148, 0.561). Conclusion: To our knowledge, this is the first study that reports CART c.517A>G polymorphism as a risk factor for obesity in adolescents. Furthermore, the present study demonstrated that the MC3R polymorphisms had a positive effect on total cholesterol, which was further enhanced in physically active individuals. Similar to other studies, LEPR Lys109Arg and LEP polymorphisms were associated with variations in obesity-related variables among Black African and Mixed Ancestry South African learners.
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    The occurance of genetic variations in the MYH9 gene and their association with CKD in a mixed South African population
    (Stellenbosch : Stellenbosch University, 2012-12) Masconi, Katya; Matsha, Tandi; Erasmus, Rajiv T.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology.
    ENGLISH ABSTRACT: The purpose of this study was to investigate the association of the selected MYH9 single nucleotide polymorphisms (SNPs) with chronic kidney disease (CKD) and its related co-morbidities in the South African mixed ancestry population residing in Bellville South, Cape Town. In 2008, two landmark studies identified SNPs in the MYH9 gene which explained most of the increased risk for non-diabetic CKD in African Americans. These polymorphisms were later found to be weakly associated with diabetic nephropathy. Three SNPs that exhibited independent evidence for association with CKD were selected (rs5756152, rs4821480 and rs12107). These were genotyped using a Taqman genotyping assay on a BioRad MiniOpticon and confirmed by sequencing in 724 subjects from Bellville South, Cape Town, South Africa. Prevalent CKD was defined based on the estimated glomerular filtration rate calculated using the modification of diet in renal disease (MDRD) formula. Chronic kidney disease was present in 214 subjects (29.6%), 96.3% were stage 3 and only 8 subjects were stage 4. In additive allelic models, adjusted for age and gender, rs5756152 demonstrated an association with kidney function whereby each G allele of rs5756152 increased eGFR by 3.67 ml/min/1.73, reduced serum creatinine by 4.5% and increased fasting plasma glucose by 0.51 mmol/L. When an interaction model was used, the effect of rs5756152 on serum creatinine, eGFR and blood glucose levels was retained, and enhanced, but only in diabetic subjects. In addition, rs4821480 T allele increased eGFR while rs12107 A allele decreased glucose levels in diabetic subjects. In contrast to reports that MYH9 SNPs are strongly associated with non-diabetic end stage renal disease, our study demonstrated that rs5756152 and rs4821480 are associated with early kidney function derangements in type 2 diabetes whilst rs12107 is associated with glucose metabolism. Our findings, along with previous reports, suggest that the MYH9 gene may have a broader genetic risk effect on different types of kidney diseases than previously thought.