John Lawrenson
Stellenbosch University
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Publication
Featured researches published by John Lawrenson.
South African Medical Journal | 2006
Bongani M. Mayosi; Kate A Robertson; Jimmy Volmink; Wole Adebo; Kingsley Akinyore; Albert Amoah; Charles Bannerman; Shan Biesman-Simons; Jonathan R. Carapetis; A.M. Cilliers; Patrick Commerford; Anne Croasdale; Albertino Damasceno; Jenny Dean; Michael Dean; Robert de Souza; Antonio Filipe; Chris Hugo-Hamman; Sally-Ann Jurgens-Clur; Pierre Kombila-Koumba; Christelle Kotzenberg; John Lawrenson; Pravin Manga; Jonathan Matenga; Tshimbi Mathivha; Phindile Mntla; Ana Olga Mocumbi; Tiny Mokone; Elijah Orola; Samuel Omokhodion
Bongani Mayosi, Kate Robertson, Jimmy Volmink, Wole Adebo, Kingsley Akinyore, Albert Amoah, Charles Bannerman, Shan Biesman-Simons, Jonathan Carapetis, Antoinette Cilliers, Patrick Commerford, Anne Croasdale, Albertino Damasceno, Jenny Dean, Michael Dean, Robert de Souza, Antonio Filipe, Chris Hugo-Hamman, Sally-Ann JurgensClur, Pierre Kombila-Koumba, Christelle Kotzenberg, John Lawrenson, Pravin Manga, Jonathan Matenga, Tshimbi Mathivha, Phindile Mntla, Ana Mocumbi, Tiny Mokone, Elijah Ogola, Samuel Omokhodion, Chapman Palweni, Adrian Pearce, Avril Salo, Baby Thomas, Kathie Walker, Charles Wiysonge, Salah Zaher
Pediatric Radiology | 2003
Mignon McCulloch; Savvas Andronikou; Elizabeth Goddard; Paul Sinclair; John Lawrenson; Simone Mandelstam; Steve Beningfield; Alastair J. W. Millar
Abstract Background. Takayasus arteritis (TA) is a chronic idiopathic inflammatory disease affecting primarily the aorta, its proximal branches and the pulmonary arteries. Objectives. To retrospectively review the angiograms of children with TA so as to describe the patterns of vascular involvement. Patients and methods. Twenty-six children with TA who differed from most other studies in that almost all of them presented with hypertension, reflecting the incidence of abdominal aortic and renal artery involvement. Results. The most consistent finding was stenosis of the aorta. Marginal irregularity/undulation of the aorta was also a useful angiographic diagnostic feature in subtle disease. The incidence of aneurysms was high compared to other studies and both fusiform and saccular aneurysms were encountered. Percutaneous transluminal angioplasty (PTA) was successful in all eight patients in whom it was performed. MRI, CT angiography and US are discussed as less invasive imaging alternatives. TA is a significant cause of renovascular hypertension in children in South Africa where there is a high incidence of tuberculous infection. Knowledge of the angiographic features and pattern of aortic involvement is essential for diagnosis and initiation of early and appropriate treatment, including PTA.
Interactive Cardiovascular and Thoracic Surgery | 2003
Henning J. Du Toit; Ulrich Von Oppell; John Hewitson; John Lawrenson; John Davies
We retrospectively reviewed the surgical treatment of 12 patients (nine female, mean age 16.1+/-8.7 years) with sub-mitral aneurysms managed in our institution between 1991 and 2002. We identified three groups of patients in accordance with the degree of posterior mitral annular involvement by the aneurysm. A single aneurysm neck was found in seven patients, multiple necks in two and involvement of the entire posterior mitral annulus in three patients. Involvement of the entire posterior annulus by the aneurysmal process has not been previously described. The mean age of this latter group 29+/-5.1 years was significantly older than the former (P=0.001), suggesting a possible progressive nature of sub-mitral aneurysms. An intracardiac surgical approach was used in six patients and a combined intra and extracardiac approach in the remainder. There was no operative mortality. The mitral valve was initially repaired in eight patients. Failure of closure of the aneurysm necessitating reoperation occurred in four patients (33.3%). An understanding of the inter-relationship between the aneurysm and mitral valve is essential for successful surgical repair. Histology of the aneurysm tissue showed rheumatic heart disease in two patients and tuberculosis in two patients. Hence, although sub-valvar aneurysms are thought to be congenital, a third of our patients had evidence of co-existent rheumatic heart disease or tuberculosis.
Journal of Child Neurology | 2012
Kathleen Walker; Anita Brink; John Lawrenson; Wendy Mathiassen; Jo M. Wilmshurst
Sydenham chorea is a post-streptococcal, autoimmune, neuropsychiatric, movement disorder. There is no effective treatment. In a randomized study, comparison was made of the outcomes of 10 children treated with standard management alone compared to 10 who received additional intravenous immunoglobulin. The outcomes were assessed using a clinical rating scale, brain single-photon emission computed tomography, and the duration of symptomatic treatment. All three outcome measurement tools found improved outcomes in the group that received intravenous immunoglobulin.
Journal of Paediatrics and Child Health | 2004
Mark Hatherill; Levin M; John Lawrenson; Hsiao Ny; Louis Reynolds; Andrew C. Argent
Objective: To describe the course of an evolving adenovirus outbreak in a multidisciplinary childrens hospital with a high‐risk patient population.
Archives of Disease in Childhood | 2005
Mark Hatherill; Shamiel Salie; Zainab Waggie; John Lawrenson; John Hewitson; Louis Reynolds; Andrew C. Argent
Aims: To describe acid–base derangements in children following open cardiac surgery on cardiopulmonary bypass (CPB), using the Fencl–Stewart strong ion approach. Methods: Prospective observational study set in the paediatric intensive care unit (PICU) of a university children’s hospital. Arterial blood gas parameters, serum electrolytes, strong ion difference, strong ion gap (SIG), and partitioned base excess (BE) were measured and calculated on admission to PICU. Results: A total of 97 children, median age 57 months (range 0.03–166), median weight 14 kg (range 2.1–50), were studied. Median CPB time was 80 minutes (range 17–232). Predicted mortality was 2% and there was a single non-survivor. These children showed mild metabolic acidosis (median standard bicarbonate 20.1 mmol/l, BE −5.1 mEq/l) characterised by hyperchloraemia (median corrected Cl 113 mmol/l), and hypoalbuminaemia (median albumin 30 g/l), but no significant excess unmeasured anions or cations (median SIG 0.7 mEq/l). The major determinants of the net BE were the chloride and albumin components (chloride effect −4.8 mEq/l, albumin effect +3.4 mEq/l). Metabolic acidosis occurred in 72 children (74%) but was not associated with increased morbidity. Hyperchloraemia was a causative factor in 53 children (74%) with metabolic acidosis. Three (4%) hyperchloraemic children required adrenaline for inotropic support, compared to eight children (28%) without hyperchloraemia. Hypoalbuminaemia was associated with longer duration of inotropic support and PICU stay. Conclusions: In these children with low mortality following open cardiac surgery, hypoalbuminaemia and hyperchloraemia were the predominant acid–base abnormalities. Hyperchloraemia was associated with reduced requirement for adrenaline therapy. It is suggested that hyperchloraemic metabolic acidosis is a benign phenomenon that should not prompt escalation of haemodynamic support. By contrast, hypoalbuminaemia, an alkalinising force, was associated with prolonged requirement for intensive care.
Genetics in Medicine | 2001
Hendrik Paul De Decker; John Lawrenson
The 22q11 deletion syndromes are a group of conditions in which a characteristic spectrum of congenital cardiac defects may be associated with a wide range of noncardiological congenital anomalies. These syndromes are all linked by a deletion in the long arm of chromosome 22. Although it is a large deletion, containing many genes, recent advances have led to the belief that the etiology of the diverse abnormalities of these syndromes may be a single gene deletion. This review outlines the historical development of the various “22q deletion syndromes,” including the DiGeorge, velocardiofacial, Takao, Cayler, and CATCH-22 syndromes, briefly describes the relevant cardiac embryogenesis, and then explains how a single gene deletion may encompass the full phenotypic spectrum.
South African Medical Journal | 2011
E.G.M. Hoosen; A.M. Cilliers; Chris Hugo-Hamman; Stephen C. Brown; John Lawrenson; Liesel Zühlke; J Hewitson
South Africa has failed to treat its children well, as demonstrated by our failure to achieve adequate progress towards the Millennium Development Goal of reducing the under-5 mortality rate, doing far worse than many poorer countries.
Pediatric Blood & Cancer | 2010
Marc Hendricks; Shakti Pillay; Alan Davidson; Rik De Decker; John Lawrenson
Kawasaki disease (KD) is a recognised precipitant of haemophagocytic lymphohistiocytosis (HLH). Although KD has been previously described in the developing world, there are no reported cases of KD preceding HLH. We report a case of a child with a persistent rash and unremitting fever consistent with the diagnosis of KD, who was found to have HLH, after intravenous gamma globulin failed to produce a clinical response. The diagnosis was made using the revised diagnostic criteria for HLH from the Histiocyte Society (1994). She fulfilled six of the eight clinical and laboratory criteria needed to make the diagnosis. Pediatr Blood Cancer 2010;54:1023–1025
South African Medical Journal | 2006
M A Roussot; John Lawrenson; John Hewitson; R Smart; H P de Decker
OBJECTIVES To compare children with Down syndrome and children without Down syndrome and investigate whether there is a significant difference in the burden that is placed on the health care system between these two groups only in respect of the repair of congenital heart disease at Red Cross War Memorial Childrens Hospital, Cape Town, South Africa. DESIGN This study is a retrospective case control review. SETTING Red Cross War Memorial Childrens Hospital, Cape Town, South Africa. SUBJECTS The sample group of 50 Down syndrome children who had received cardiac surgery between January 1998 and June 2003 was compared with a control group of 50 nonsyndromic children who had received cardiac surgery during the same period. OUTCOME MEASURES Sex and diagnoses (cardiac and noncardiac), number of days spent in hospital and in ICU, complication rates, re-operation rates, early mortality rates, planned further cardiac surgery. Costs of these outcomes were not quantified in exact monetary terms. RESULTS There was no significant difference between the two groups in terms of the burden that was placed on the health care system. Similar complication rates, re-operation rates and early mortality rates were recorded for both groups. The Down syndrome group appeared to benefit more from cardiac surgery than the non-Down syndrome group. CONCLUSION Denying cardiac surgery to children with Down syndrome does not improve the efficiency of resource allocation. It is therefore not reasonable to suggest that the problem of scarce resources can be ameliorated by discriminating against children with Down syndrome.