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Welcome to the NWU Repository, the open access Institutional Repository of the North-West University (NWU-IR). This is a digital archive that collects, preserves and distributes research material created by members of NWU. The aim of the NWU-IR is to increase the visibility, availability and impact of the research output of the North-West University through Open Access, search engine indexing and harvesting by several initiatives.

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KWANTIFISERING VAN MITOCHONDRIALE RESPIRASIE OM AANGEBORE MITOCHONDRIALE DEFEKTE TE ONDERSOEK
(North-West University, 1999) D. J. Pieterse; Pretorius P.J Steyn S.J
Genetic defects of oxidative phosphorylation account for a large variety of clinical symptoms in childhood. The mitochondrial respiratory chain catalyses the oxidation of fuel molecules with the concomitant energy transduction into ATP. During the oxidation process electrons are transferred to oxygen via the energy transducing complexes of the respiratory chain. When a defect occurs in one of these complexes of the respiratory chain, the electrons can not be transferred through that complex and less electrons are transferred to oxygen and consequently less ATP is produced. The diagnosis of respiratory chain deficiencies are difficult because the complexes are coded for by both chromosomal and mitochondrial DNA. The Metabolic Laboratory of the Biochemistry and Microbiology department at the PU for CHE is involved in the diagnoses and detection of inherited metabolic defects, therefor there is a need for a standardised method with which an inherited metabolic defect can be traced in patients. Many different methods for the quantification of mitochondrial respiration were examined. Mitochondrial respiration can for example be measured with polarography as a function of the amount of oxygen used or the amount of ATP produced over a certain time. The activities of the different mitochondrial complexes can also be quantified separately. Due to the difficulty in obtaining tissue (like muscle tissue) from paediatric patients we decided to determine mitochondrial respiration in situ in fibroblasts. The method has the advantage that the mitochondria don't have to be isolated and that several tests can be done with a small amount of tissue. It is also a lot easier to get fibroblasts than it is to get paediatric muscle tissue. The cells are made permeable with digitonin so that the mitochondrial complex specific substrates can reach the mitochondria in the cells. We decided to quantify the amount of ATP produced in a certain time by the use of a luciferase-luciferin enzyme system. The method is very sensitive yet very easy to perform. We decided to standardise the method for quantification of in situ mitochondrial respiration due to the variations found in literature concerning this method. The aspects that were standardised included the determination of the optimum concentration digitonin to permeabilise the fibroblasts, optimisation of the luciferase-luciferin enzyme reaction, optimisation of the extraction of ATP from cells, determination of the optimum substrate concentration for the different complexes as well as the linear range for each reaction. In addition, with the use of complex specific inhibitors, it was necessary to determine to what extent the various mitochondrial complexes are specifically responsible for the observed respiration. The in situ method for ATP quantification, after standardisation, was used on fibroblasts from people who seemed to have no defects, for the determination of control values. The method was then tested and evaluated on fibroblasts from two patients with possible inherited metabolic diseases. The one patient was diagnosed with a possible cytochrome c oxidase defect and the other patient with a possible complex I defect. Both the patients' respiration values for the involved complexes were lower than the control respiration values. These results were verified by determining the respiration activities of the individual complexes through classical in vitro analyses. With this, a technique was standardised with which mitochondrial respiration defects can be examined in for example paediatric patients.
DIE GEBRUIK VAN DESKUNDIGE STELSELS VIR 'n GEIDENTIFISEERDE KOMPONENT VAN STRATEGIESE BESTUUR BINNE KLEINSAKE-ONDERNEMINGS
(North-West University, 1993) Jacobus Coenraad Pretorius; Bruwer P.J.S
STANDARDIZATION OF THE ABERRANT BEHAVIOUR CHECKLIST FOR WITRAND HOSPITAL
(North-West University, 1992) Kim Priest-Jacobs; Pretorius-Heuchert J.W
This research explores the standardization of the Aberrant Behaviour Checklist (ABC) specifically for the population at Witrand Hospital. Author Kim Priest-Jacobs emphasizes that intellectual disability involves both sub-average mental functioning and significant deficits in adaptive behavior. Because existing diagnostic tools often lack local norms or relevant linguistic translations, this study adapts the ABC into Afrikaans to ensure more accurate clinical assessments. The project also aims to develop a psychosis sub-scale based on DSM-III-R criteria to better identify mental illness in patients with severe cognitive impairments. By establishing these standardized procedures, the hospital can more effectively measure the impact of therapeutic interventions and medical treatments. Ultimately, the work seeks to improve the quality of care and communication within multidisciplinary teams treating institutionalized individuals.
DEFEKTE TETRAHIDROBIOPTERIENHOMEOSTASE IN 'N SWART FAMILIE MET HIPERFENIELALANIENEMIE
(North-West University, 1993) Nicoleen Potgieter
In 1984 the Department of Biochemistry of the Potchefstroom University for Christian Higher Education introduced a metabolic screening programme. Results from a two year research project on defective amino acid metabolism of 1443 clinically selected patients are presented. Utilization of a dual screening approach consisting of one-dimensional thin layer chromatography and automatic amino acid analysis led to the identification of various abnormalities associated with known metabolic defects. Seven different types of amino acidurias were diagnosed in a total of 15 positively tested patients. Hyperphenylalaninemia accounted for 5 of the amino acidurias of which one was a very rare case of malfunctional phenylalanine metabolism. Amongst the total screened group, atypical ninhydrin positive components were found in approximately 13 % of the analyzed urine samples. It was not possible to link the presence of these components to any known defect of the amino acid metabolism. Given that the presence of the atypical ninhydrin positive components complicates the interpretation of laboratory results, it was necessary to investigate their nature and origin. Different separation techniques were applied in an attempt to isolate the metabolites responsible for the atypical ninhydrin colour complexes. However, it was not possible to isolate these metabolites using the normal protocol for isolation of amino acids. This led to the conclusion that their physico-chemical properties did not correspond with that of known amino acids. GC-MS analysis indicated structural similarities between these atypical compound(s) and amino acid conjugates associated with some organic acidurias. Analysis of a consignment of samples obtained from newborns on antibiotic treatment focused the attention on medication as possible cause of the atypical ninhydrin positive components. GC-MS analysis indicated the presence of a metabolite of the penicillin molecule in the urine of patients receiving antibiotics. These results were confirmed by a penicillin loading test on a healthy individual. Hyperphenylalaninemia (HPA) is not prevalent in Negroids. Therefore, the case of a black baby girl with HP A discovered during this study was exceptional. Using a dual screening procedure, elevated levels of phenylalanine were detected in different plasma specimens of the patient. The extent of the elevation was such that it could not be associated with phenylketonuria (PKU), but rather a variant of the disease. An approach investigating the disease on metabolite as well as enzyme level was formulated. A tentative diagnosis was made on the overall status of metabolites in the phenylalanine hydroxylase system, after which the diagnosis was confirmed by enzymatic analysis. Metabolite analyses revealed the presence of phenolic compounds in the patient's urine. A phenylalanine loading test indicated that the clearance rate of the excess phenylalanine from the patient's bloodstream was impaired. However, her phenylalanine levels did not rise as much as commonly expected in the case of PKU. Although this result was indicative of a tetrahydrobiopterin-defect (BH4), the patient did not react positively to the administration of 20 mg BH4/kg mass. The patient's excretion pattern of urinary pterines, as well as her low levels of active BH4 were consistent with a DHPR-defect. The reduced levels of neurotransmitter metabolites in cerebrospinal fluid of the patient also indicated a DHPR-defect. Information obtained from the metabolite analyses indicated DHPR-defect as the possible cause of hyperphenylalaninemia in the patient. This diagnosis was confirmed when no DHPR-activity could be demonstrated in dried blood spots from the patient. Given that the patient did not react to a high dose of 20 mg BH4 per kilogram of weight, the disorder is referred to as non-responsive dihydropteridine reductase deficiency. The patient described here is not only the second case of non- responsive DHPR-defect in the world, but also the first black patient diagnosed with this disease.
PAKKETVERGOEDING EN SOSIALE VERANTWOORDELIKHEID
(North-West University, 1998) Frederick Petrus Pretorius