John M Pettifor | University of the Witwatersrand (original) (raw)

Papers by John M Pettifor

Orthopaedic Proceedings, Sep 1, 2005

Osteogenesis imperfecta (OI) is characterised by decreased bone density and increased bone fragil... more Osteogenesis imperfecta (OI) is characterised by decreased bone density and increased bone fragility. We studied the effect of bisphosphonates on clinical features and bone mass, enrolling to the study 22 children with OI treated with these drugs. Sixteen of them received continuous oral alendronate and six received cyclical IV pamidronate. Evaluation included mobility score, fracture rate, chemistry of skeletal remodelling, iliac crest biopsy and DEXA assessment of bone mass. After 18 months of bisphosphonate therapy, 10 patients were fully assessed. There was a definite clinical improvement, with significantly improved mobility (p =0.04), a reduction in the annualised fracture rate from 1.27 to 0.44, and significant improvement in bone mass density (p =0.01).

Bone reports, Jun 1, 2018

South African journal of physiotherapy, Sep 30, 1981

Orthopaedic Proceedings, Mar 1, 2002

The purpose of this study was to determine factors contributing to the high incidence of fracture... more The purpose of this study was to determine factors contributing to the high incidence of fractures in patients with spastic quadriplegic cerebral palsy in residential care, and to assess the effect of vitamin D therapy. Over a period of four years, 20 patients in a cohort of 88 had sustained 56 long bone fractures. We compared them to an age-matched group from the same cohort with no history of fractures. The mobility of patients, who spent their time indoors, was severely restricted in both groups. There was radiological and biochemical evidence of rickets and osteomalacia in both groups, but the disease was more severe in the fracture group. There was a significant relationship between the number of fractures and the use of anticonvulsant therapy. Administration of vitamin D (5 000 IU per day) to both the fracture and control group over three months resulted in a marked increase in mean serum calcium (p =0.01), and a dramatic decrease (p We recommend vitamin D supplementation for all non-ambulatory children with cerebral palsy in residential care who do not get regular exposure to sunlight.

PubMed, Mar 10, 1984

Cystinosis is thought to be rare in Black patients. Two cases of nephropathic cystinosis in Black... more Cystinosis is thought to be rare in Black patients. Two cases of nephropathic cystinosis in Blacks in early childhood are reported. One patient presented with classic features of Fanconi's syndrome with failure to thrive and rickets, while the other had polyuria, growth failure and rickets. This article highlights the need for the exclusion of cystinosis in any Black patient presenting with Fanconi's syndrome.

PubMed, Sep 4, 1982

A new neonatal maintenance solution (Neonatalyte; Sabax) was administered to 12 newborn infants w... more A new neonatal maintenance solution (Neonatalyte; Sabax) was administered to 12 newborn infants with respiratory distress. Under closely controlled conditions, the infusion was commenced at a mean age of 12 +/- 10 hours. The mean serum potassium level increased from 4,6 +/- 0,6 mmol/l to 5,6 +/- 1,4 mmol/l (P less than 0,02), while in 5 infants (42%) hyperkalaemia (greater than or equal to 6,5 mmol/l) occurred within 8 hours of commencement of Neonatalyte infusion. The mean serum calcium level decreased from 2,1 mmol/l on day 1 to 1,7 mmol/l on day 2 (P less than 0,001) and was 1,8 mmol/l on day 3 (P less than 0,01), despite mean calcium intakes of 18,33 and 45 mg on days 1, 2 and 3 respectively. The early hypocalcaemia may be related to the phosphate content of Neonatalyte. We conclude that Neonatalyte is not an ideal solution for sick newborn infants who cannot be fed orally for the first few days of life.

Archives of Disease in Childhood, Feb 1, 1980

44 randomly selected infants under age one year with suspected lower respiratory infections were ... more 44 randomly selected infants under age one year with suspected lower respiratory infections were investigated for the presence of subclinical rickets. Seven infants had metaphyseal changes at the wrist compatible with a diagnosis of rickets and all of these infants had 25-hydroxy-vitamin D (25-OHD) concentrations <12 ng/ml. Serum calcium and phosphorus concentrations were normal in all 44 children. Alkaline phosphatase concentrations did not correlate with the presence of metaphyseal changes. The clinical presence of craniotabes or splaying and loss of definition of the anterior ends of the ribs on x-rays did not correlate with metaphyseal changes at the wrist or with 25-OHD concentrations. An x-ray of the wrist is essential to confirm the presence of subclinical rickets and the at-risk infant can be detected by measuring serum 25-OHD concentrations.

Publisher Summary This chapter discusses with the influencing factors and optimization of the pea... more Publisher Summary This chapter discusses with the influencing factors and optimization of the peak bone mass. Peak Bone Mass (PBM) is the amount of bone tissue achieved in an individual at the end of skeletal maturation. It remains relatively constant until the premenopausal period in women and a little later in men, when bone mass decreases and is important because it influences fracture rates in later life. PBM is achieved at different times in males and females. In females, there is little gain in bone mass after menarche. In males, it continues to increase until the beginning of the third decade. The basic factors influencing PBM are the genetic influence of parents, independent of body size of the subject, intrauterine factors, nutritional factors, endocrine factors, and physical activity. The major determinant of PBM is genetic inheritance, but there are several lifestyle and nutritional factors that optimize PBM: nutrition, exercise, eating disorders, and smoking and excessive alcohol ingestion have been shown to reduce bone mass.

Journal of Bone and Mineral Research, Apr 17, 2023

The anatomical record, Dec 1, 1990

ABSTRACT

The Lancet Diabetes & Endocrinology, Mar 1, 2019

South African Journal of Child Health, Mar 29, 2016

JBMR plus, Dec 21, 2020

Most studies evaluating BMD in human immunodeficiency virus (HIV)-infected populations have focus... more Most studies evaluating BMD in human immunodeficiency virus (HIV)-infected populations have focused on antiretroviral therapy (ART)-experienced patients. In this study, the association between HIV-1 and/or depot medroxyprogesterone acetate (DMPA) and BMD among untreated HIV-1-infected women in a resource-limited setting was assessed before long-term exposure to ART. The data were then compared with that of the 2005-2008 United States National Health and Nutrition Examination Survey data for non-Hispanic White and Black women. Women aged 18-35 years, recruited from health facilities in Kampala, Uganda, were classified based on their combination of HIV-1 status and DMPA use: (i) HIV-1-infected current DMPA users, (ii) HIV-1-infected previous DMPA users, (iii) HIV-1-infected nonhormonal-contraceptive users, and (iv) HIV-uninfected nonhormonal-contraceptive users. All HIV-1infected women reported being ART-naïve at baseline. BMD was measured at the lumbar spine, total hip, and femoral neck using DXA. Multivariate linear regression was used to assess the association between HIV-1 and/or DMPA and BMD Z-scores. Baseline data were analyzed for 452 HIV-1-infected (220 nonhormonal users, and 177 current and 55 previous DMPA users) and 69 HIV-1uninfected nonhormonal-contraceptive users. The mean age was 26.1 years (SD, 4.2) with a median duration of DMPA use among current users of 24.0 months [medians (interquartile range), 12-48]. A higher proportion of HIV-1-infected previous (12.7%) or current DMPA users (20.3%) and nonhormonal users (15.0%) had low BMD (Z-score ≤−2 at any of the three sites) compared with agematched HIV-1-uninfected women (2.9%). HIV-1 infection and DMPA use were independently associated with significantly lower mean BMD Z-scores at all sites, with the greatest difference being among HIV-1-infected current DMPA users (5.6%-8.0%) versus uninfected nonhormonal users. Compared with non-Hispanic White and Black women, the Ugandan local reference population had generally lower mean BMD at all sites. Newer treatment interventions are needed to mitigate BMD loss in HIV-1-infected women in resource-limited settings.

African Journal of Health Professions Education, Nov 21, 2015

In Africa we are faced with enormous challenges in healthcare that require intensive and high-qua... more In Africa we are faced with enormous challenges in healthcare that require intensive and high-quality research; yet, there is a lack of clinically trained research scientists and of support for those who do exist. If South Africa (SA) in particular and Africa in general are going to tackle their huge healthcare burdens appropriately, we need well-trained scientists with clinical expertise to lead research endeavours and to train our future clinical researchers. Because of the 'serious decline in clinical research activity and capacity' , the Academy of Science of South Africa (ASSAf) examined the state of clinical research and related training in South Africa. In 2009, the report published by ASSAf recommended, among others, 'stimulating PhD degrees for professional graduates through the widening of the necessary opportunity and support mechanisms'. [1] The recommended target was 500 PhDs to be produced in the clinical research field over the next 10 years. [1] In the USA the MD-PhD pathway appears to be the most prevalent way of training clinician scientists. [2] The federal government through the National Institutes of Health (NIH) is the major funder of such programmes. [3] While the MD-PhD programme has been successful, the postgraduate training of clinicians in research is also showing promising outcomes. [4] A similar programme was established in the UK in 2000 following reports from the Royal College of Physicians and the Academy of Medical Sciences of the United Kingdom. [5] However, this process, while well funded and highly competitive, has had low PhD completion rates. [3] The importance of investment in the development of clinician scientists cannot be overestimated. However, not all governments invest or invest sufficiently in this area. While the ASSAf report [1] recommended 'raising the Research and Development budget to 2% of the gross domestic product (GDP), of which 20% should be allocated to health research' , as well as other measures, to date this is only slowly translating into funding for capacity development in the clinical sciences in SA. In 2009, the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, SA, supported by the Carnegie Corporation of New York, chose to initiate a programme around the development of appropriately skilled academic clinicians, of which the clinician scientist was an integral part. This article describes the setting up of the programme, the aim of which is to provide opportunities for young clinicians to develop research skills through enrolling for a PhD.

The Journal of Steroid Biochemistry and Molecular Biology, Nov 1, 2016

Concern has been expressed about the rising incidence of nutritional rickets with its associated ... more Concern has been expressed about the rising incidence of nutritional rickets with its associated long-term sequelae in children globally. In order to address the condition worldwide, it is imperative that accurate figures of its incidence are available particularly in at-risk communities. In order to obtain these figures, various screening tools and diagnostic criteria have been used with no standardization of methodologies, resulting in varying prevalences which may under- or over-estimate the prevalence depending of the techniques used. This review discusses the advantages and disadvantages of various screening tests used to diagnose rickets in communities. Clinical signs characteristic of rachitic deformities have been used extensively, but are likely to over-estimate the prevalence and are dependent on the clinical skills of the observer. Biochemical tests such as alkaline phosphatase and 25-hydroxyvitamin D have also been proposed. There is no consensus on the usefulness of alkaline phosphatase as a screening tool, while there is general agreement that the measurement of vitamin D status is unhelpful in screening for rickets. Finally, the confirmation of the presence of active rickets in suspected infants and children is dependent on radiographic findings, although these may be less helpful in adolescents whose growth plates might be closed or nearly so. In order to obtain uniformity in screening for rickets globally, the is a need for consensus among public health specialists, paediatric endocrinologists and those interested in paediatric bone disease as to the best methods to be employed to determine the prevalence of rickets, particularly in communities with limited resources.

The Journal of Pediatrics, Oct 1, 1987

A 2-year-old boy had signs and symptoms of chronic hypervitaminosis A. A course of increasing sev... more A 2-year-old boy had signs and symptoms of chronic hypervitaminosis A. A course of increasing severity led to eventual death. A younger brother later had similar clinical features. Chicken liver spread containing up to 420 IU/g vitamin A was the likely source of intoxication. Markedly elevated circulating retinyl ester levels have persisted in the surviving sibling for 3 Subsequent years despite severe restriction of vitamin A intake. A therapeutic trial of the carbohydrate-derived complexing agent 2-hydroxypropyl-~-cyclodextrin was initiated. Circulating retinyl esters transiently increased during the infusion (from 407 to 4791 ~g/dL), and urinary total vitamin A excretion, undetectable before infusion, increased to 23 ~g/dL after infusion. The frequency of hypervitaminotic episodes has decreased somewhat in the 2 years since the infusion, probably related to dietary vitamin A restriction. The occurrence of this syndrome in two brothers, while a sister ingesting the same diet remains completely healthy, suggests an inherited variance in tolerance to vitamin A intake.

PubMed, Dec 1, 1998

Several recent submissions to the SAMJ have provided readers with insight into public health stra... more Several recent submissions to the SAMJ have provided readers with insight into public health strategies, and the pertinent comments of the various authors have flagged both positive and negative aspects of these strategies. We refer specifically to the article by Mathews, van Rensburg and Coetzee on the syndromic approach to sexually transmitted diseases/ the comment by Zar et al. on the Integrated Management of Childhood illness (IMCI),' and the paper by Chopra et al. on the implementation of primary health care (PHC)3 The common thread running through these articles is the need to identify and cost-effectively manage common local health problems (affordable, accessible, appropriate health care).

Rheumatic Diseases Clinics of North America, Feb 1, 2012

Calcified Tissue International, 2008