Publications by authors named "Grobbelaar J"

Adverse drug reactions and fatalities can result from therapeutic drug use due to genetic deficiencies in drug-metabolizing enzymes. In cases where ancillary testing may not reveal a clear cause of death, molecular autopsies can be valuable. However, forensic mortuaries do not retain DNA samples in all cases, which hinders subsequent genetic testing if it is later deemed necessary.

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Background: Studies have found that, at presentation, human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) has a less advanced primary tumour, more advanced lymph node spread and commonly has cystic metastatic lymph nodes in comparison to HPV-negative OPSCC.

Objectives: To compare the radiological features of HPV-positive and HPV-negative OPSCC in South African patients.

Method: A retrospective cross-sectional study was conducted at a large South African hospital.

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Unlabelled: Phosphaturic mesenchymal tumours (PMT) are rare, benign lesions and the most common tumour to cause tumour-induced osteomalacia (TIO), a paraneoplastic syndrome. Patients frequently exhibit severe osteomalacia, accompanied by multiple fractures, which significantly impair their quality of life. Complete surgical resection is curative.

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Introduction: Most paediatric upper respiratory infections are virally mediated and result in self-limiting reactive lymphadenopathy. In children younger than 5 years, retropharyngeal lymph nodes may give rise to deep neck space infections in this potential space. Retropharyngeal infections are rare after 5 years because lymph nodes undergo atrophy.

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The rising mortality and morbidity rate of head and neck cancer (HNC) in Africa has been attributed to factors such as the poor state of health infrastructures, genetics, and late presentation resulting in the delayed diagnosis of these tumors. If well harnessed, emerging molecular and omics diagnostic technologies such as liquid biopsy can potentially play a major role in optimizing the management of HNC in Africa. However, to successfully apply liquid biopsy technology in the management of HNC in Africa, factors such as genetic, socioeconomic, environmental, and cultural acceptability of the technology must be given due consideration.

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Objective: The purpose of this study was to determine the knowledge and practice of nurses at an academic hospital regarding the handling of red blood cells (RBCs) and platelets.

Methods: A descriptive study was performed using a paper-based questionnaire. Nurses from 12 wards where these products are frequently transfused were purposefully selected to participate.

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Growth of Chlorella vulgaris was characterized as a function of irradiance in a laboratory turbidostat (1L) and compared to batch growth in sunlit modules (5-25L) of the commercial NOVAgreen photobioreactor. The effects of variable sunlight and culture density were deconvoluted by a mathematical model. The analysis showed that algal growth was light-limited due to shading by external construction elements and due to light attenuation within the algal bags.

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Laryngotracheal stenosis develops when scar tissue forms in the trachea and, rarely, in the larynx itself. Symptoms depend on the degree of airway obstruction and can range from asymptomatic to upper airway obstruction severe enough to cause death. We report on 21 patients who underwent tracheal resection for severe stenosis.

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Background: Approximately one-third of hepatoblastoma (HB) patients have associated congenital abnormalities, but familial recurrence is rare, except in association with familial adenomatous polyposis (FAP). This correlation may be missed if not actively sought, with implications for long-term outcome and management.

Methods: We retrospectively investigated 3 families with an HB-familial polyposis connection, from a cohort of 113 FAP families (1989 - 2010).

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The maximum quantum yield (Φ (max)), calculated from the maximum chlorophyll a specific photosynthetic rate divided by the quantum absorption per unit chlorophyll a, is 8 photons or 0.125 mol C per mol Quanta light energy. For the average solar radiation that reaches the earth's surface this relates to a photosynthetic yield of 1.

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Polymorphic sequence-characterised marker assays from a recent diversity study on the Ascomycete fungus Ophiostoma quercus reported that some isolates from Africa were genetically distinct from O. quercus. In the present study, these African isolates were compared with authentic O.

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Eight polymorphic markers were developed from South African isolates of Ophiostoma quercus. The genome was screened for repeat regions using the fast isolation by amplified fragment length polymorphism of sequences containing repeats protocol and 20 de novo primer pairs flanking putative microsatellite regions were designed. Eight loci were optimized and their polymorphisms evaluated by sequencing.

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Few studies have considered the relationship between social capital and stigmatizing attitudes. The aim of this study is to assess the relationship between HIV stigmatizing attitudes and individual perceptions of social capital in South Africa. The study surveyed 619 community members to assess whether social capital predicted personal and attributed HIV stigmatizing attitudes.

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The purpose of this study was to examine the presentation of AIDS-related stigma and knowledge within the political context of the South African government's response to the AIDS epidemic. It was during the 2000 - 2004 period that key government officials publicly challenged the orthodox views of HIV/AIDS, with the South African president, Thabo Mbeki, actively positing the primary role of poverty and other socio-economic stressors in the progression of the AIDS epidemic. This discursive position had real-time effects for AIDS policy-making and ultimately delayed the implementation of a national antiretroviral (ARV) rollout programme.

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Lymphoid hyperplasia is common in HIV positive patients. The aim of this study was to determine the response to radiotherapy. Thirty-three adult patients with recurrent tonsillitis or upper airway obstruction due to tonsillar hyperplasia and conformed histology of follicular hyperplasia were included.

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Although pulmonary hypertension secondary to upper airway obstruction caused by adenotonsillar hyperplasia has been well described, the association between laryngeal papillomatosis and pulmonary hypertension has not previously been documented. We report three patients with pulmonary hypertension due to upper airway obstruction caused by laryngeal papillomatosis. Pulmonary hypertension can contribute to significant preoperative and postoperative morbidity and cause intraoperative complications.

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A concentration-dependent toxicity of hydrogen peroxide (H(2)O(2)) was observed on growth yield, chlorophyll a content and chlorophyll fluorescence characteristics of the green microalga Scenedesmus obliquus under laboratory batch culture conditions. The addition of sodium nitroprusside, a nitric oxide (NO) donor, in combination with H(2)O(2) prevented chlorophyll losses, and the inhibition level of growth yield, maximum quantum yield of photosystem II (PSII) and the light-adapted quantum yield of PSII were significantly reduced. The antioxidant compounds, penicillamine and thiourea also reduced the damage caused by H(2)O(2) exposure.

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The apparent low incidence of colon cancer in the Black population of South Africa has been ascribed to a non-Western diet. The present authors report the identification of two common 5-bp deletions at codons 1309 and 1061 of the adenomatous polyposis coli (APC) gene in a Xhosa and Zulu patient, respectively. The in vitro transcription/translation test (PTT) and a non-radioactive heteroduplex method, which facilitates resolution of enzymatically amplified DNA by agarose gel electrophoresis, were used for mutation detection.

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Five previous cases of extrarenal Wilms tumor (EWT) occurring in the uterus have been reported. The oldest patient was 22 years. We report a case of uterine EWT occurring in a 42-year-old woman.

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Multiple sclerosis (MS) is believed to be an autoimmune process occurring in genetically susceptible individuals after an appropriate environmental exposure. We have exploited the homogeneous Afrikaner population of European ancestry to investigate the likelihood that iron dysregulation, in association with infectious and/or autoimmune disease susceptibility, may underlie the MS phenotype in a subgroup of patients. The functional Z-DNA forming repeat polymorphism of the natural resistance-associated macrophage protein-1 (NRAMP1) gene was analyzed in 104 patients diagnosed with MS and 522 Caucasian controls.

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Objective: To determine the molecular basis and establish a routine molecular diagnostic service for familial adenomatous polyposis coli (FAP) families in South Africa.

Design: The coding region of the adenomatous polyposis coli (APC) gene in affected FAP kindreds was screened using heteroduplex analysis, single-strand conformation polymorphism analysis and the protein truncation test.

Setting: Department of Human Genetics, University of Stellenbosch, and the Cancer Research Campaign Laboratories, Department of Pathology, University of Edinburgh and Molecular Medicine Centre, Western General Hospital, Edinburgh, Scotland (academic visit of 6 months).

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Colorectal adenomas are macroscopically visible morphological changes of the mucosa that can develop focal carcinoma in the absence of surgical intervention. The successive molecular changes proposed to occur at different stages in the adenoma-carcinoma sequence were primarily based on DNA studies of exophytic, polypoid-type adenomas. Not all colorectal lesions, however, display an exophytic phenotype and a presumed distinct colorectal neoplasm, the nonpolypoid adenoma, was subsequently described as a precursor of colorectal cancer.

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Adenomas are established pre-malignant lesions in colorectal carcinogenesis. To date the adenoma-carcinoma sequence for the development of colorectal carcinoma (CRC) has been based largely on molecular data of exophytic, polypoid-type adenomas. Subsequently, a different type of adenoma has been identified: the flat adenoma, so called for its flat, non-exophytic appearance, making it less likely to be detected during conventional endoscopy.

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