South African medical schools: Current state of selection criteria and medical students' demographic profile.

BACKGROUND: Selection of medical students at South African (SA) medical schools must promote equitable and fair access to students from all population groups, while ensuring optimal student throughput and success, and training future healthcare practitioners who will fulfil the needs of the local society. In keeping with international practices, a variety of academic and non-academic measures are used to select applicants for medical training programmes in SA medical schools. OBJECTIVES: To provide an overview of the selection procedures used by all eight medical schools in SA, and the student demographics (race and gender) at these medical schools, and to determine to what extent collective practices are achieving the goals of student diversity and inclusivity. METHODS: A retrospective, quantitative, descriptive study design was used. All eight medical schools in SA provided information regarding selection criteria, selection procedures, and student demographics (race and gender). Descriptive analysis of data was done by calculating frequencies and percentages of the variables measured. RESULTS: Medical schools in SA make use of academic and non-academic criteria in their selection processes. The latter include indices of socioeconomic disadvantage. Most undergraduate medical students in SA are black (38.7%), followed by white (33.0%), coloured (13.4%) and Indian/Asian (13.6%). The majority of students are female (62.2%). The number of black students is still proportionately lower than in the general population, while other groups are overrepresented. CONCLUSION: Selection policies for undergraduate medical programmes aimed at redress should be continued and further refined, along with the provision of support to ensure student success.

Appropriateness of computed tomography and magnetic resonance imaging scans in the Eden and Central Karoo districts of the Western Cape Province, South Africa.

INTRODUCTION: Computed tomography (CT) and magnetic resonance imaging (MRI) are an essential part of modern healthcare. Marked increases in clinical demand for these imaging modalities are straining healthcare expenditure and threatening health system sustainability. The number of CT and MRI scans requested in the Eden and Central Karoo districts of the Western Cape Province, South Africa (SA), almost doubled from 2011 to 2013. OBJECTIVE: To determine the appropriateness of CT and MRI scans and relate this to the requesting department and clinician. METHODS: This was a retrospective analytical cohort study. All scans during October 2012 were analysed as a sample. Appropriateness of scans was determined using the American College of Radiologists (ACR) Appropriateness Criteria and the Royal College of Radiology Guidelines. Appropriateness was also correlated back to the requesting department and clinician. RESULTS: Of a total of 219 scans, 53.0% were abnormal. Overall 6.4% of scans were considered inappropriate. Interns and registrars requested no inappropriate scans. The orthopaedics department scored the highest rate of appropriate scans (80.0%) and the oncology department the highest rate of inappropriate scans (20.8%). CONCLUSION: The limited resources available for healthcare in a developing country like SA should be a motivation to implement control mechanisms aimed at appropriate utilisation of imaging examinations. The Eden and Central Karoo districts have a low rate of inappropriate scans (6.4%). We recommend that the current preauthorisation system by consultants and other senior clinicians continues, but with increased clinician awareness of the ACR Appropriateness Criteria and the Royal College guidelines.

The composition of egg yolk absorbed by fasted ostrich (Struthio camelus L.) chicks from 1 to 7 days posthatching and for ostrich (Struthio camelus L.) chicks from 1 to 16 days posthatching on a prestarter broiler diet.

This study was performed to obtain information on yolk utilization in fasted and fed ostrich chicks posthatching. The fasted trial lasted for 7 d, whereas the fed trial continued for 16 d. Fasted ostrich chicks showed a decrease of 31.3 g of BW, with yolk weight decreasing by 28.9 g daily after hatching. Yolk weight comprised 28% of 1-d-old ostrich chick BW and decreased to 12% at 7 d of age. Only 44.4% of the fasted ostrich chick yolk was assimilated over the trial period. Crude protein content of the yolk decreased by 13.2 g daily. Fat content increased by 1.77% daily, whereas total yolk fat weight decreased with 8.91 g daily. Slaughter weight of fed ostrich chicks increased, with yolk weight decreasing by 16.3 g daily. Yolk content for fed ostrich chicks was 26% of BW at 2 d of age. Ostrich chicks absorb 30% of yolk over the first 4 d, 67% after 8 d, and only deplete the yolk after 14 d posthatch. Fasted ostrich chicks absorbed the yolk content at a rate of 28.9 g/d, compared with 22.3 g/d over the first 8 d and 16.3 g/d over the 16 d for fed ostrich chicks. The CP content of the yolk decreased by 6.84 g daily in fed ostrich chicks, whereas fat content of the yolk increased by 1.39% daily, although total yolk fat weight decreased by 6.61 g daily. Yolk weight and total CP decreased faster over the first 7 d in the fasted ostrich chicks compared with the fed ostrich chicks, which indicated that the decrease in yolk weight could be attributed to absorption of protein from the yolk. Fat content decreased faster over the first 8 d from the yolk of the fed ostrich chicks compared with that from the yolk of the fasted ostrich chicks, which could indicate that external feed has a positive influence on the absorption of fat from the yolk content.

Influence of CYP2B6 516G>T polymorphism and interoccasion variability (IOV) on the population pharmacokinetics of efavirenz in HIV-infected South African children.

OBJECTIVE: To investigate the influence of CYP2B6 516G>T polymorphism, as a covariate, and of interoccasion variability (IOV) on the oral clearance (CL/F) of efavirenz (EFV) in treatment-naïve black South African children over a period of 24 months post-antiretroviral therapy (ART) initiation. METHODS: HIV-infected black children (n = 60, aged 3-16 years), with no prior exposure to ART, eligible to commence ART and attending an outpatient clinic were enrolled into this study. Blood samples were taken at mid-dose interval at 1, 3, 6, 12, 18 and 24 months post-ART initiation. EFV plasma samples were determined with an adapted and validated LC/MS/MS method. Genotyping of the CYP2B6 G516T single nucleotide polymorphism (SNP) was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). NONMEM was used for the population pharmacokinetic modelling. RESULTS: EFV concentrations below 1 µg/mL accounted for 18% (116/649), EFV concentrations >4 µg/mL accounted for 29.5% (192/649) and concentrations within the therapeutic range (1-4 µg/mL) represented 52.5% (341/649) of all the samples determined. The covariates age, weight and CYP2B6 G516Tgenotype were included in the final model with population estimates for CL/F determined as 2.46, 4.60 and 7.33 L/h for the T/T, G/T and G/G genotype groups respectively. CONCLUSIONS: The inclusion of both age and weight to predict accurate EFV CL values for the respective genotype groups within this paediatric population was required, whereas the addition of gender and body surface area did not improve the predictions. The importance of introducing IOV in a PK model for a longitudinal study with sparsely collected data was again highlighted by this investigation.

Expression of the H-subunit and L-subunit of ferritin in bone marrow macrophages and cells of the erythron during cellular immune activation.

BACKGROUND: The expression of the two types of ferritin subunits, the H-subunit and L-subunit, has been shown to be differentially regulated by cytokines. The primary aim of the present study was to quantitatively measure the expression of the H-subunit and L-subunit of ferritin in bone marrow macrophages and cells of the erythron in patients with chronic T-helper cell type-1 immune stimulation. METHODS: The expression of the H-subunit and L-subunit of ferritin in bone marrow macrophages and cells of the erythron was quantitatively evaluated by post-embedding immunolocalisation with immunogold transmission electron microscopy. RESULTS: The present study showed up-regulation of the H-subunit of ferritin in the bone marrow macrophage in patients with pronounced cellular immune activation (94.7±37.3 counts/µm(2); n=31 vs 72.4±34.0 counts/µm(2); n=13, p-value=0.037). CONCLUSION: This supports a possible role for H-subunit rich ferritins in the hypoferraemia of chronic disease.

Pro- and anti-inflammatory cytokines during immune stimulation: modulation of iron status and red blood cell profile.

Forty-eight patients were subdivided according to C-reactive protein (CRP) levels, resulting in 19 patients with normal (2.8 ± 2.8 mg/L) and 29 with elevated (82.2 ± 76.2 mg/L) CRP levels. The elevated CRP group had iron and red blood cell (RBC) profiles characteristic of chronic immune stimulation (CIS), and the normal CRP group, profiles of true iron deficiency. Normal relationships between storage iron, bioavailable iron, and RBC indices were absent in the elevated CRP group-implying the role of iron as major determinant of the RBC profile to be diminished during CIS. The elevated CRP group had significant increases in proinflammatory cytokines (INF-γ, TNF-α, Il-1ß, Il-6, and Il-8). Anti-inflammatory cytokine levels were normal, except for Il-10, supporting previous indications that Il-10 contributes to reducing bioavailable iron. Regression analysis suggested decreases in transferrin to be related to increases in Il-8 and an increase in ferritin to be related to a decrease in Il-12 levels. TGF-ß levels were positively related to transferrin and negatively to ferritin.

Bone density and depression in premenopausal South African women: a pilot study.

OBJECTIVE: It is posited that the effect of depression on BMD is dependent on the severity of depression. Conflicting evidence exists regarding this possible association. This study investigated the association between depression and low bone mineral density (BMD). METHODS: The hypothesis was investigated in a random sample of volunteers (n=40) and in premenopausal female psychiatric patients (n=5) diagnosed with recurrent severe major depression. The outcome measures were BMD (DEXA); depression (Beck Depression Inventory and Psychological General Well-being Scale) and 24-hour saliva cortisol levels (ELISA). In a comparison of women (4 of the 40 i.e. "control" subjects) with negligible symptoms of depression and the five patients with severe recurrent major depression- BMD, depression, saliva cortisol and bone turnover markers were measured and compared. Pro-inflammatory status (IL-1 and TNF-alpha) was investigated in the psychiatric patients only. RESULTS: In the random - non clinical - sample of women (n=40), 26 exhibited normal BDM and 14 exhibited low BMD. Drepressive symptoms and cortisol level were not significantly different between these two groups. Women with severe recurrent major depression (n=5)exhibited lower median BMD T-scores, higher overall bone turnover and higher 24-hour cortisol levels compared to "control" subjects (n=4). The psychiatric patients also exhibited elevated IL-1 levels. CONCLUSION: The effect of depression on BMD may be dependent on the depression severity, IL-1 and cortisol are possible mediators in depression-induced BMD loss.

Neural correlates of consciousness.

A basic understanding of consciousness and its neural correlates is of major importance for all clinicians, especially those involved with patients with altered states of consciousness. In this paper it is shown that consciousness is dependent on the brainstem and thalamus for arousal; that basic cognition is supported by recurrent electrical activity between the cortex and the thalamus at gamma band frequencies; aand that some kind of working memory must, at least fleetingly, be present for awareness to occur. The problem of cognitive binding and the role of attention are briefly addressed and it shown that consciousness depends on a multitude of subconscious processes. Although these processes do not represent consciousness, consciousness cannot exist without them.

Learners' knowledge and and perceptions of voluntary counselling and testing for HIV and AIDS in the Free State Province.

The study investigated the perceptions of the youth regarding Voluntary Counselling and Testing (VCT) and sexual aspects related to HIV and AIDS. The study was grounded in qualitative methodology, using 4 focus group interviews for data collection triangulating the results with field notes and literature. The participants of the four focus groups proved to be well informed on the topic and had clear perceptions concerning several aspects. They were very positive regarding the advantages of VCT for the prevention and management of HTV and AIDS. The participants recognised the need for the youth to be better informed about VCT and HIV and AIDS. They were much concerned by the lack of parental involvement in sexual education as well as the permissiveness of the youth who partook in alcohol and drug abuse as well as prostitution. Participants of the study stated that this problem was exacerbated by poverty and poor socio economic conditions.

Dysrhythmogenic potential in acute admissions to psychiatric hospitals and clinics.

UNLABELLED: Co-morbidity between physical disease, especially cardiovascular, and psychological disturbances is well documented. In psychiatric patients, the potential for dysrhythmogenic incidences is increased by the fact that many psychiatric medications influence cardiovascular function. AIM: The aim of the study was to examine the dysrhythmogenic potential of 30 psychiatric patients (group A), irrespective of diagnoses or medication, at admission to psychiatric institutions. METHODS: The dysrhythmogenic potential was determined in terms of heart rate-corrected QT intervals (QTc), heart rate-corrected JT intervals (JTc), QT and JT dispersion (QTcd and JTcd) between leads V1 and V6, and heart rate variability (HRV) as determined from lead V6 of the ECG. Values were compared with 30 age- and gender-matched controls (group B). In the second part of the study the dysrhythmogenic indicators were assessed in a patient group (group C; n = 43) with only psychiatric disorders and compared to a group with psychiatric as well as medical disorders (group D; n = 27). RESULTS: The patient group A had significantly higher values than the control group for mean QTc (V6) (0.4579 +/- 0.0328 vs 0.4042 +/- 0.0326; p = 0.0470), mean JTc (V6) (0.3883 +/- 0.0348 vs 0.3064 +/- 0.0271; p = 0.0287) and mean QT and JT dispersion values (QTcd = 0.0443 +/- 0.0203 vs 0.0039 +/- 0.0053 and JTcd = 0.0546 +/- 0.1075 vs 0.0143 +/- 0.1450, p < 0.05). A statistically significant difference (p < 0.0001) was found between the patients' (group A) HRV and that of the controls (group B). No statistically significant differences were found between the values of the dysrhythmogenic indicators for patients with only psychiatric illness (group C) and those with psychiatric as well as medical disorders (group D). CONCLUSIONS: Psychiatric patients at the point of admission to psychiatric institutions may have an increased dysrhythmogenic potential, not necessarily caused by physical disease. The potential of an augmented risk for cardiovascular incidents in psychiatric patients should be considered when treating such patients.

Ferritin and ferritin isoforms II: protection against uncontrolled cellular proliferation, oxidative damage and inflammatory processes.

Ferritin is a major iron storage protein involved in the regulation of iron availability. Each ferritin molecule comprises 24 subunits. Various combinations of H-subunits and L-subunits make up the 24-subunit protein structure and these ferritin isoforms differ in their H-subunit to L-subunit ratio, as well as in their metabolic properties. Ferritin is an acute-phase protein and its expression is up-regulated in conditions such as uncontrolled cellular proliferation, in any condition marked by excessive production of toxic oxygen radicals, and by infectious and inflammatory processes. Under such conditions ferritin up-regulation is predominantly stimulated by increased reactive oxygen radical production and by cytokines. The major function of ferritin in these conditions is to reduce the bio-availability of iron in order to stem uncontrolled cellular proliferation and excessive production of reactive oxygen radicals. Ferritin is not, however, indiscriminately up-regulated in these conditions as a marked shift towards a predominance in H-subunit rich ferritins occurs. Preliminary indications are that, while the L-subunit primarily fulfils the conventional iron storage role, the H-subunit functions primarily as rapid regulator of iron availability, and perhaps indirectly as regulator of other cellular processes. It is suggested that the optimum differential expression of the two subunits differ for different cells and under different conditions and that the expression of appropriate isoferritins offers protection against uncontrolled cellular proliferation, oxidative stress and against side effects of infectious and inflammatory conditions.

Ferritin and ferritin isoforms I: Structure-function relationships, synthesis, degradation and secretion.

Ferritin is the intracellular protein responsible for the sequestration, storage and release of iron. Ferritin can accumulate up to 4500 iron atoms as a ferrihydrite mineral in a protein shell and releases these iron atoms when there is an increase in the cell's need for bioavailable iron. The ferritin protein shell consists of 24 protein subunits of two types, the H-subunit and the L-subunit. These ferritin subunits perform different functions in the mineralization process of iron. The ferritin protein shell can exist as various combinations of these two subunit types, giving rise to heteropolymers or isoferritins. Isoferritins are functionally distinct and characteristic populations of isoferritins are found depending on the type of cell, the proliferation status of the cell and the presence of disease. The synthesis of ferritin is regulated both transcriptionally and translationally. Translation of ferritin subunit mRNA is increased or decreased, depending on the labile iron pool and is controlled by an iron-responsive element present in the 5'-untranslated region of the ferritin subunit mRNA. The transcription of the genes for the ferritin subunits is controlled by hormones and cytokines, which can result in a change in the pool of translatable mRNA. The levels of intracellular ferritin are determined by the balance between synthesis and degradation. Degradation of ferritin in the cytosol results in complete release of iron, while degradation in secondary lysosomes results in the formation of haemosiderin and protection against iron toxicity. The majority of ferritin is found in the cytosol. However, ferritin with slightly different properties can also be found in organelles such as nuclei and mitochondria. Most of the ferritin produced intracellularly is harnessed for the regulation of iron bioavailability; however, some of the ferritin is secreted and internalized by other cells. In addition to the regulation of iron bioavailability ferritin may contribute to the control of myelopoiesis and immunological responses.

Quinsy treated by aspiration: the volume of pus at initial aspiration is an accurate predictor of the need for subsequent re-aspiration.

OBJECTIVE: The aim of this study was to determine an accurate indicator of the need for second aspiration of peritonsillar abscesses the day after initial aspiration. SETTING: A tertiary otolaryngology care centre. PARTICIPANTS: Fifty patients aged between 11 and 49 years with suspected peritonsillar abscess. STUDY DESIGN: A prospective case series. OUTCOME MEASURES: The potential indicators investigated included volume of pus at initial aspiration and clinical indicators suggesting persistent pus (dysphagia, odynophagia and trismus). The outcome measure was the presence of pus at subsequent aspiration. RESULTS: A linear correlation was found between volume of first aspirate and presence of pus on re-aspiration (r = 0.9753). A volume of pus <3 mL on initial aspiration accurately predicted <0.5 mL pus on re-aspiration. Sixty-four per cent (32) patients had 3 mL or more pus on initial aspiration and in all there was at least 1 mL or more pus on second aspiration. Clinical indicators correlated less well, with a average coefficient on first aspiration of 0.62 and on second aspiration of 0.35. CONCLUSION: The volume of pus on initial aspiration is a very reliable indicator in assessing the need for re-aspiration of peritonsillar abscesses. If 3 mL or more of pus are aspirated on the first occasion these patients should be seen the next day and have a further aspiration. Clinical symptoms and signs are not useful indicators.

The central noradrenergic system: an overview.

The central noradrenergic system belongs to a group of brainstem neuromodulatory systems previously referred to as the ascending reticular activating system. In this article a heuristic model is presented of the central noradrenergic system depicting the major projections to other cerebral areas, its interactions with other neuromodulatory systems, mechanisms through which it can influence cerebral function, as well as the major functions and disorders associated with alterations in central noradrenergic activity. It is not the aim of this paper to provide fine detail on the various aspects, but rather to provide a concise overview where structure and function, as well as the interactions with other systems are brought together. The contents of the paper are summarized in a diagram.

Supportive neurodevelopmental evidence for ADHD as a developmental disorder.

A baby is dependent on its primary caregiver (hereafter referred to as 'mother') for its emotional regulation. The development of emotional self-regulation is dependent on the growth and myelinisation of connections between cortical (control) and limbic (emotion) structures in the infant brain. The subcortical sympathetic limbic system is dominant from birth, and it is only at 14-18 months of age that the parasympathetic cortical inhibitory part develops. The maturation of specifically the right orbitofrontal cortex, which dominates both the sympathetic and parasympathetic limbic systems, is essential for the regulation of emotion for the rest of an individual's life. Behavioral hyperactivity, impulsivity and inattention are considered normal for children in the early practising phase (10-14 months). This stage is characterised by sympathetic dominance stimulated by the ventral tegmental limbic circuit. We hypothesise that children with Attention Deficit Hyperactivity Disorder remain stuck in this phase, and accordingly do not enter the next stage of emotional development, i.e., the late practising period, in which the lateral tegmental limbic circuit, which stimulates the parasympathetic system develops. Parental reactions, which may contribute to this block in emotional development, include: largely ignoring their child, until the child does something the parent disapproves of, then scolding the child, without consoling the child again afterwards. This leads susceptible children to develop defensive hyperactivity and inattention in order to avoid a shame state they are unable to cope with. Implications for therapy are that caregivers should be taught firstly to give lots of positive attention to their child, and if necessary to scold, to console the child immediately afterwards. If this can be achieved consistently, the child will have the chance to develop their parasympathetic lateral limbic circuit, and eventually right orbitofrontal dominance over both limbic circuits, which translates into the ability to self-regulate their emotional states.

Prediction of the chemical composition of freeze dried ostrich meat with near infrared reflectance spectroscopy.

Near infrared reflectance spectroscopy (NIRS) was used to predict the chemical composition of freeze-dried ostrich meat samples. Tenderloin (M. ambiens), big drum (M. iliofibularis) and fan fillet (M. gastrocnemius) samples (n=160) were included in the study. Samples were minced, freeze-dried and analysed according to standard laboratory procedures for ash, dry matter (DM), crude protein (CP) and fat content. Samples were scanned (1100-2500 nm) and partial least-square regression (PLSR) was used to predict the chemical composition. Multiple correlation coefficients (r) and standard errors of calibration (SEC) for the chemical analysis of freeze-dried ostrich meat were: ash (0.72; 0.29%); DM (0.72; 1.01%); CP (0.98; 0.55%); and fat (0.99; 0.29%). The r values for the validation set and the standard error of performance (SEP) for the different constituents were: ash (0.71; 0.23%); DM (0.84; 0.72%); CP (0.97; 0.64%); and fat (0.99; 0.18%). Calibrations were accurate for CP and fat.