SUNScholar

SUNScholar is a leading digital archive for the preservation and promotion of the research output of Stellenbosch University.

 

Recent Submissions

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The effect of a post‑anaesthesia high‑care unit (PAHCU) admission on mobilization, length of stay and in‑hospital mortality post‑surgery in low energy neck of femur fracture patients
(Springer Link, 2024-01-09) Essa, S.; Venter, S.; Jordaan, J. D.
Purpose/aim: With an ageing population and an increase in fragility fractures of the hip (FFH), the role of an anaesthetist is evolving to include more peri-operative care. A post-anaesthesia high-care unit (PAHCU) should enhance care in postoperative patients. To our knowledge, there are no studies that have investigated the effect of a PAHCU admission on postoperative outcomes after FFH. This study aimed to compare post-operative outcomes of FFH patients admitted to PAHCU versus a standard post-operative orthopaedic ward (POOW). Methodology: A retrospective cohort study was conducted on adult patients with FFH who underwent surgery between January 2019 and December 2020 at our institution. Data were sourced from electronic medical records. SPSS version 28 was used to analyse data. Results: A total of 231 patients were included. The PAHCU group (n = 35) displayed a higher burden of chronic illness and higher peri-operative risk scores as compared to the POOW group (n = 196). Median time to mobilize (TTM) in PAHCU was 84 h vs. 45 h in POOW group (p = 0.013). Median length of stay (LOS) in PAHCU was 133 h vs. 94 h in POOW (p = 0.001). The in-hospital mortality was 2.9% (n = 1) for PAHCU and 3.6% (n = 7) for POOW (p = 1). The 30-day mortality was 11.8% (n = 4) for PAHCU and 10.1% (n = 19) in POOW. Conclusion: PAHCU admission resulted in delayed time to surgery and TTM, together with prolonged LOS, compared to those managed in POOW. However, these mortality rates remained comparable in both groups. This study contributes valuable insights into post-operative care of FFH patients in a resource-poor setting.
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BA.2.12.1, BA.4 and BA.5 escape antibodies elicited by Omicron infection
(Springer Nature, 2022-06-17) Cao, Yunlong; Yisimayi, Ayijiang; Jian, Fanchong; Song, Weiliang; Xiao, Tianhe; Wang, Lei; Du, Shuo; Wang, Jing; Li, Qianqian; Chen, Xiaosu; Yu, Yuanling; Wang, Peng; Zhang, Zhiying; Liu, Pulan; An, Ran; Hao, Xiaohua; Wang, Yao; Wang, Jing; Feng, Rui; Sun, Haiyan; Zhao, Lijuan; Zhang, Wen; Zhao, Dong; Zheng, Jiang; Yu, Lingling; Li, Can; Zhang, Na; Wang, Rui; Niu, Xiao; Yang, Sijie; Song, Xuetao; Chai, Yangyang; Hu, Ye; Shi, Yansong; Zheng, Linlin; Li, Zhiqiang; Gu, Qingqing; Shao, Fei; Huang, Weijin; Jin, Ronghua; Shen, Zhongyang; Wang, Youchun; Wang, Xiangxi; Xiao, Junyu; Xie, Xiaoliang Sunney
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages BA.2.12.1, BA.4 and BA.5 exhibit higher transmissibility than the BA.2 lineage1. The receptor binding and immune-evasion capability of these recently emerged variants require immediate investigation. Here, coupled with structural comparisons of the spike proteins, we show that BA.2.12.1, BA.4 and BA.5 (BA.4 and BA.5 are hereafter referred collectively to as BA.4/BA.5) exhibit similar binding affinities to BA.2 for the angiotensin-converting enzyme 2 (ACE2) receptor. Of note, BA.2.12.1 and BA.4/BA.5 display increased evasion of neutralizing antibodies compared with BA.2 against plasma from triple-vaccinated individuals or from individuals who developed a BA.1 infection after vaccination. To delineate the underlying antibody-evasion mechanism, we determined the escape mutation profiles2, epitope distribution3 and Omicron-neutralization efficiency of 1,640 neutralizing antibodies directed against the receptor-binding domain of the viral spike protein, including 614 antibodies isolated from people who had recovered from BA.1 infection. BA.1 infection after vaccination predominantly recalls humoral immune memory directed against ancestral (hereafter referred to as wild-type (WT)) SARS-CoV-2 spike protein. The resulting elicited antibodies could neutralize both WT SARS-CoV-2 and BA.1 and are enriched on epitopes on spike that do not bind ACE2. However, most of these cross-reactive neutralizing antibodies are evaded by spike mutants L452Q, L452R and F486V. BA.1 infection can also induce new clones of BA.1-specific antibodies that potently neutralize BA.1. Nevertheless, these neutralizing antibodies are largely evaded by BA.2 and BA.4/BA.5 owing to D405N and F486V mutations, and react weakly to pre-Omicron variants, exhibiting narrow neutralization breadths. The therapeutic neutralizing antibodies bebtelovimab4 and cilgavimab5 can effectively neutralize BA.2.12.1 and BA.4/BA.5, whereas the S371F, D405N and R408S mutations undermine most broadly sarbecovirus-neutralizing antibodies. Together, our results indicate that Omicron may evolve mutations to evade the humoral immunity elicited by BA.1 infection, suggesting that BA.1-derived vaccine boosters may not achieve broad-spectrum protection against new Omicron variants.
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Dialogue, horizon and chronotope : using Bakhtin’s and Gadamer’s ideas to frame online teaching and learning
(Springer Nature, 2024-04-05) Rule, Peter
The information explosion and digital modes of learning often combine to inform the quest for the best ways of transforming information in digital form for pedagogical purposes. This quest has become more urgent and pervasive with the ‘turn’ to online learning in the context of COVID-19. This can result in linear, asynchronous, transmission-based modes of teaching and learning which commodify, package and deliver knowledge for individual ‘customers’. The primary concerns in such models are often technical and economic – technology as a cost-effective ‘solution’ to educational challenges. In this paper I argue for the importance of dialogic learning space in teaching and learning by means of Information and Communication Technologies, whether in the form of fully online learning, blended learning or face-to-face encounters using ICT affordances. Although the 20th Century theorists Mikhail Bakhtin (1895–1975) and Hans-Georg Gadamer (1900–2002) produced their seminal works before the advent of ICTs, they were both concerned with the quality and authenticity of human engagement with texts and with other persons and contexts. Besides a shared interest in dialogue as an ontological feature of human life and being, they both used spatiotemporal concepts for understanding and interpreting texts. The article draws on Gadamer’s notions of dialogue and horizon, and Bakhtin’s notions of dialogue and chronotope, to conceptualize dialogic possibilities for online education. Its purpose is to provide a framework, grounded in Bakhtin’s and Gadamer’s ideas, for a dialogic approach to online teaching and learning in higher education.
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The Effect of ß-Glucan Prebiotic on Kidney Function, Uremic Toxins and Gut Microbiome in Stage 3 to 5 Chronic Kidney Disease (CKD) Predialysis Participants: A Randomized Controlled Trial
(MDPI, 2022-02-14) Ebrahim, Zarina; Proost, Sebastian; Tito, Raul Yhossef; Raes, Jeroen; Glorieux, Griet; Moosa, Mohammed Rafique; Blaauw, Renee
There is growing evidence that gut dysbiosis contributes to the progression of chronic kidney disease (CKD) owing to several mechanisms, including microbiota-derived uremic toxins, diet and immune-mediated factors. The aim of this study was to investigate the effect of a ß-glucan prebiotic on kidney function, uremic toxins and the gut microbiome in stage 3 to 5 CKD participants. Fifty-nine participants were randomized to either the ß-glucan prebiotic intervention group (n = 30) or the control group (n = 29). The primary outcomes were to assess kidney function (urea, creatinine and glomerular filtration rate), plasma levels of total and free levels of uremic toxins (p-cresyl sulfate (pCS), indoxyl-sulfate (IxS), p-cresyl glucuronide (pCG) and indoxyl 3-acetic acid (IAA) and gut microbiota using 16S rRNA sequencing at baseline, week 8 and week 14. The intervention group (age 40.6 ± 11.4 y) and the control group (age 41.3 ± 12.0 y) did not differ in age or any other socio-demographic variables at baseline. There were no significant changes in kidney function over 14 weeks. There was a significant reduction in uremic toxin levels at different time points, in free IxS at 8 weeks (p = 0.003) and 14 weeks (p < 0.001), free pCS (p = 0.006) at 14 weeks and total and free pCG (p < 0.001, p < 0.001, respectively) and at 14 weeks. There were no differences in relative abundances of genera between groups. Enterotyping revealed that the population consisted of only two of the four enterotypes: Bacteroides 2 and Prevotella. The redundancy analysis showed a few factors significantly affected the gut microbiome: these included triglyceride levels (p < 0.001), body mass index (p = 0.002), high- density lipoprotein (p < 0.001) and the prebiotic intervention (p = 0.002). The ß-glucan prebiotic significantly altered uremic toxin levels of intestinal origin and favorably affected the gut microbiome.
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The effectiveness of a first-year module presented as an accelerated learning programme to repeating students for subsequent learning
(University of the Free State, 2022-12-23) Ontong, Juan M.; Bruwer, Armand; Schonken, Chrystal
The use of an accelerated learning programme as an intervention to allow failing students to repeat a module in an accelerated format instead of having to redo a module over a semester or academic year has various academic, economic, and social benefits. Accelerated learning programmes are, however, often criticised in the literature for surface learning that may influence subsequent learning. Using a quantitative approach, this study statistically analysed the grades achieved by three distinct groups of students for a first-year financial accounting module and their subsequent second-year financial accounting module. The study found no statistical difference between students who repeated a module over the traditional academic period and those who repeated the module in an accelerated format. This study contributes to the limited research on accelerated learning programmes for repeating a module. The results provide empirical evidence that supports the questioning of the notion that accelerated learning programmes only lead to surface learning, and results are presented that advocate for the implementation of accelerated learning programmes as an effective mode for repeating students to follow to achieve academic success, given the various benefits.