319 research outputs found

    Solid phase extraction of β-N-methylamino-L-alanine (BMAA) from South African water supplies

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    β-N-methylamino-L-alanine (BMAA) has been implicated in amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC) and is assumed to cause or contribute to this neurodegenerative disease after bioaccumulation and slow release of BMAA from a protein-associated form and conversion to the excitatory carbamate form. BMAA has been detected in varying quantities in freshwater cyanobacteria, causing some concern regarding the potential for direct dietary consumption of BMAA-containing water and subsequent intoxication. Considering the BMAA content reported in cyanobacteria and the concentrations cyanobacterial cells can reach in a bloom in freshwater impoundments, BMAA concentrations could potentially reach the mg∙ℓ-1 range. BMAA has been shown to cause neuronal injury and even death at μM exposure ranges. Current analytical techniques are, however, insufficiently sensitive to detect the molecule at concentrations of less than 250 ng∙ℓ-1 without prior concentration. Safe levels have yet to be determined for BMAA in potable water but these levels may be far below this analytical limit. It is therefore necessary to quantify potential exposure at these relatively low levels. A simple method is described here for high levels of BMAA recovery from a range of waters (78-103 ± 5%), as well as an amino acid matrix (57 ± 5%), saline solution (63 ± 5%), tap water (61 ± 5%) and a preliminary analysis of BMAA concentrations from bloom and non-bloom freshwater supply samples. No exogenous BMAA was detected in water supplies, despite high concentrations in the bloom material, suggesting that BMAA is not released or exported by the cyanobacteria or that rapid degradation, binding or uptake of BMAA occurs in these environments. This method is not suggested for marine samples a very low recovery percentages are seen in the presence of sodium.Keywords: β-N-methylamino-L-alanine, BMAA, cyanobacterial bloom, solid phase extractio

    The role of treatment delays in surgical site infection after appendicectomy in a South African rural regional hospital

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    Background. Delays to surgery for acute appendicitis in low- and middle-income countries lead to significant morbidity.Objectives. To investigate the role of time to surgery in the development of complicated appendicitis and surgical site infection (SSI) in a rural referral hospital in South Africa (SA).Methods. A prospective cohort study was conducted of all patients presenting to a regional hospital in SA with acute appendicitis during 2017. Inpatient interview and data collection were followed by 30-day post-surgical follow-up to assess time periods to surgery and operative outcomes.Results. A total of 188 patients underwent surgery for acute appendicitis. The median (interquartile range (IQR)) age was 19 (3 - 73) years, and 62% were male. The median (IQR) time from symptoms to surgery was 60 (42 - 86) hours and from hospital admission to surgery 8 (4 - 16) hours. Forty-one percent were managed laparoscopically, 62% had complicated appendicitis, and 25% developed SSI. Time from symptoms to surgery >72 hours was associated with an increased risk of complicated appendicitis (odds ratio (OR) 4.32; 95% confidence interval (CI) 1.36 - 13.75; p=0.013). Patients with SSI had an increased median delay of 15 hours (p=0.05) compared with those without SSI. Multivariable analysis showed that the risk of SSI increased with complicated appendicitis (OR 8.96; 95% CI 2.73 - 29.41; p<0,001) and decreased with laparoscopic surgery (OR 0.21; 95% CI 0.07 - 0.59; p=0.003). Time to surgery had no effect on the risk of SSI in adjusted analyses.Conclusions. Delays to surgery beyond 72 hours significantly increased complicated appendicitis, an important risk factor for SSI. Access to facilities with surgical capability and the use of laparoscopic surgery are modifiable risk factors for SSI

    The correlation between C-reactive protein and toxic granulation of neutrophils in the peripheral blood

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    Background. During inflammation, the serum concentrations of granulocyte colony-stimulating factor (G-CSF), plasma interleukin-6 (IL-6), and C-reactive protein (CRP) increase. A positive correlation between CRP and the percentages of neutrophils exhibiting toxic granulation during inflammation has been demonstrated, and that the fluctuations of CRP and toxic granulation of neutrophils were similar. Objectives. We studied whether grading of toxic granulated neutrophils can be used as a surrogate marker for infection or inflammation, and also be an easier method than previously described methods. Materials and methods. We graded 357 consecutive peripheral blood slides from patients on whom a full blood count with differential count and CRP level was performed, according to intensity of toxic granulation in the neutrophil population, according to a newly proposed grading system. Results. The CRP range was between 1 and 530.3 mg/l. The results confirm the association between a rise in CRP and progressive intensity of toxic granulation in neutrophils in peripheral blood. Kruskal-Wallis equality of populations rank test showed a statistically significant difference between the graded categories (p=0.0001). The Trend test was also statistically significant (p=0.000). Conclusion. The proposed system can be applied to patients with inflammatory or infectious conditions, where grading of toxic granulation of neutrophils can possibly be used as a surrogate marker to assess infection or inflammation and their response to treatment. It may be of particular use in cases where traditional infectious or inflammatory markers cannot be used, owing to inherent problems associated with the respective conditions

    Risky sexual behaviours of high-school pupils in an era of HIV and AIDS

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    Objective. To identify risky sexual behaviours and demographic factors that place high-school pupils at risk of HIV and AIDS. Methods. A cross-sectional study was undertaken to explore factors influencing the sexual behaviour of high-school pupils (mean age 15.4 years; SD 1.11). Structured self-reported questionnaires were completed by all grade 10 pupils (N=805) at all the Wentworth, Durban, public high schools. Results. Significant gender differences in sexual practices were reported, such as males being more likely to engage in sexual activity than females (OR 4.92;

    Model Predictive Control Tailored to Epidemic Models

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    Investigating hair zinc concentrations in children with and without atopic dermatitis

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    Background. Atopic dermatitis (AD) is a common chronic inflammatory skin condition that disproportionately affects children and is associated with reduced quality of life. Zinc deficiency may contribute to the pathogenesis of AD because zinc plays a role in epidermal barrier integrity and the immune system. Systematic review evidence suggests that low zinc is associated with AD, but limitations of included studies support further investigation.Objectives. To investigate hair zinc concentrations in children with AD v. healthy controls in a low- to middle-income country setting.Methods. One hundred and five children aged 1 - 12 yea­rs participated in a frequency-matched for age case-control study. The outcome variable, AD, was confirmed by a clinician and corroborated using the UK Working Party criteria. The primary predictor, long-term average zinc concentration, was determined by measuring hair zinc using inductively coupled mass spectrometry. Baseline demographic characteristics, anthropometry and measures of socioeconomic status were included in our logistic regression analysis. Subgroup analysis was performed where interaction terms suggested effect modification.Results. Using data from the overall sample, population median hair zinc was not significantly different between children with AD and healthy controls. However, subgroup analysis suggested a clinically and statistically significant difference in median zinc between children with AD (175.35 µg/g) and healthy controls (206.4 µg/g) in the older age group (5 - 12 years) (p=0.01). In this age group, multivariable logistic regression analysis also found significantly decreased hair zinc concentrations in AD (odds ratio 0.83; 95% confidence interval 0.66 - 0.96; p=0.046).Conclusions. The inverse association between zinc status and AD in children aged 5 - 12 years in our setting is consistent with the international literature. The clinical importance of decreased zinc levels in AD is not yet known. Further investigation into relevant underlying mechanisms seems warranted given the global reach of AD, its effect on quality of life, and the low cost of potential zinc-based interventions.

    Predischarge transcutaneous bilirubin screening reduces readmission rate for hyperbilirubinaemia in diverse South African newborns: A randomised controlled trial

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    Background. In South Africa (SA), healthy term newborns are usually discharged Ë‚72 hours after delivery. Discharged babies remain at risk for severe hyperbilirubinaemia if it is not identified early. Hyperbilirubinaemia is an important cause of readmission, and also leads to neonatal mortality and morbidity. Use of transcutaneous bilirubin (TcB) screening before hospital discharge has been controversial.Objectives. To test the clinical benefits of TcB screening of healthy newborns before discharge for the outcomes of readmission for jaundice and severe hyperbilirubinaemia in a randomised controlled trial (RCT).Methods. This was a RCT. We compared predischarge TcB screening with visual assessment (alone) for jaundice in apparently healthy newborns at a public tertiary hospital in Cape Town, SA. Patients or study participants were not involved in the study design and implementation.Results. Of the 1 858 infants, 63% were black, 35% of mixed race and 1% white. There was a significant reduction in the rate of readmission for jaundice (risk ratio (RR) 0.25; 95% confidence interval (CI) 0.14 - 0.46; p<0.0001) and in the incidence of severe hyperbilirubinaemia (RR 0.27; 95% CI 0.08 - 0.97; p=0.05) with the use of TcB screening compared with visual inspection.Conclusions. Predischarge TcB screening is superior in identifying newborns at risk of severe hyperbilirubinaemia compared with visual inspection. We recommend that every newborn, regardless of skin pigmentation, should receive objective bilirubin screening before hospital discharge. Universal bilirubin screening in newborns could potentially reduce hyperbilirubinaemia-related morbidity and mortality

    Professional boundaries: crossing a line or entering the shadows?

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    This article explores the professional boundaries guidance for social workers. It presents research findings from the formal literature, from agency codes of practice, from telephone interviews with regulatory and professional bodies and from an exercise using ‘snowballing techniques’ in which informants responded to brief scenarios illustrating boundary dilemmas. The findings suggest that formal research plays little part in the guidance that individuals use to help them determine professional boundaries. Similarly, only 10–15 per cent of informants made regular reference to regulatory and professional codes of practice, with an even smaller percentage quoting specific sections from these codes. A slightly larger group (15–20 per cent) made fairly regular reference to their agency's policy documents. However, a clear majority relied on their own sense of what is appropriate or inappropriate, and made their judgements with no reference to any formal guidance. Agency guidance tended to ignore the ambiguous areas of practice and seemed to act as an insurance policy, brought out and dusted off when something goes awry. The authors caution against ever-increasing bullet points of advice and prescription, and advance a notion of ethical engagement in which professionals exercise their ethical senses through regular discussion of professional boundary dilemmas

    Enchytraeus crypticus Avoid Soil Spiked with Microplastic.

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    Microplastics (MPs) of varying sizes are widespread pollutants in our environment. The general opinion is that the smaller the size, the more dangerous the MPs are due to enhanced uptake possibilities. It would be of considerably ecological significance to understand the response of biota to microplastic contamination both physically and physiologically. Here, we report on an area choice experiment (avoidance test) using Enchytraeus crypticus, in which we mixed different amounts of high-density polyethylene microplastic particles into the soil. In all experimental scenarios, more Enchytraeids moved to the unspiked sections or chose a lower MP-concentration. Worms in contact with MP exhibited an enhanced oxidative stress status, measured as the induced activity of the antioxidative enzymes catalase and glutathione S-transferase. As plastic polymers per se are nontoxic, the exposure time employed was too short for chemicals to leach from the microplastic, and as the microplastic particles used in these experiments were too large (4 mm) to be consumed by the Enchytraeids, the likely cause for the avoidance and oxidative stress could be linked to altered soil properties
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