Research Articles (Medical Bioscience)

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Browsing by Author "Abdul-Rasool, Sahar"

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    Autosomal recessive congenital cataract in captive-bred vervet monkeys (Chlorocebus aethiops)
    (Wiley, 2018) Magwebu, Zandisiwe E.; Abdul-Rasool, Sahar; Seier, Jurgen V.; Chauke, Chesa G.
    BACKGROUND: The aim of the study was to evaluate the genetic predisposition of congenital cataract in a colony of captive-bred vervet monkeys. METHODS: Four congenital cataract genes: glucosaminyl (N-acetyl) transferase 2 (GCNT2), heat shock transcription factor 4 (HSF4), crystallin alpha A (CRYAA) and lens intrinsic membrane protein-2 (LIM2) were screened, sequenced and analysed for possible genetic variants in 36 monkeys. Gene expression was also evaluated in these genes. RESULTS: Fifteen sequence variants were identified in the coding regions of three genes (GCNT2, HSF4 and CRYAA). Of these variations, only three were missense mutations (M258V, V16I and S24N) and identified in the GCNT2 transcripts A, B and C, respectively, which resulted in a downregulated gene expression. CONCLUSION: Although the three missense mutations in GCNT2 have a benign effect, a possibility exists that the candidate genes (GCNT2, HSF4 and CRYAA) might harbour mutations that are responsible for total congenital cataract.
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    Cytotoxicity of methamphetamine exposure on sertoli cells: a pilot study with implications for male infertility
    (Taylor and Francis Ltd., 2025) Fisher, David; Zabida, Omar; Abdul-Rasool, Sahar; Willemse, Chontrelle
    Methamphetamine (Meth), a psychoactive drug, has been shown to reduce testicular weight and decrease sperm count, indicating its potential role in contributing to male infertility. We therefore assessed Meth’s effects (0.1–100 μM) on TM4 Sertoli cell viability, toxicity, and proliferation (trypan blue exclusion assay), mitochondrial activity (MA) (XTT assay), while transepithelial electrical resistance (TEER) was used to examine monolayer permeability. The acute study (only 24-hour Meth exposure) mimics recreational users and the chronic study, the Meth addicts who require daily doses (24–96 hours). Acute Meth treatment had minimal impact on TM4 Sertoli cell viability and toxicity, while chronic exposure resulted in reduced cell viability and increased toxicity in a dose-related manner. Acute exposure suppressed cell division at 72 hours, while chronic exposure suppressed cell division at both 72 and 96 hours. Long-term suppression of MA was observed for both acute and chronic Meth exposure (20 µM and 100 µM). Both acute and chronic Meth exposure affected permeability across the blood–testis barrier (BTB), which persisted for up to 96 hours. Given the pivotal role of Sertoli cells in spermatogenesis, our findings provide a two-pronged mechanism for Meth-induced male infertility and indicate that short-term exposure may have long-term effects on the germinal epithelium. © 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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    The synergistic and neuroprotective effects of alcohol–antioxidant treatment on blood–brain barrier endothelial cells
    (Wiley-Blackwell, 2020) Fisher, David W.; Thomas, Kelly Angelique; Abdul-Rasool, Sahar
    Background: Alcohol (EtOH) is reported to adversely affect one of the most crucial roles of the blood–brain barrier (BBB), the regulation of its permeability, thereby compromising the stability of the homeostatic environment of the brain. The central component of the BBB, endothelial cells (ECs), regulates BBB transcellular transport, while their paracellular pathways are made virtually impermeable by molecular structures called tight junctions (TJs). These TJs are composed of proteins, such as claudin-5, a protein involved in the regulation of paracellular permeability and of key interest in this study. Methods and Results: The working hypothesis of this study postulated that the high levels of antioxidants (AOs) in the fermented Aspalathus linearis (Rooibos; Rf) tincture may protect the ECs of the BBB against oxidative stress induced by EtOH exposure. Cells were exposed for 24 hours to selected concentrations of EtOH (25 and 100 mM), Rf (containing an antioxidant equivalence of 1.9 nM Aspalathin), and cotreatments of EtOH and Rf. Cell viability, live cell number, and toxicity were analyzed using the trypan blue exclusion assay. RT-qPCR was implemented to quantify claudin-5 transcription. In addition, permeability (Transepithelial Electrical Resistance) of bEnd5 monolayers was measured. The experimental timeline for the above-mentioned parameters was 24 and 48 hours. Conclusions: Our study showed that simultaneous exposure of Rf and EtOH was able to negate the effects of EtOH on cell viability and cell proliferation, but was not able to reverse or reduce the effects of EtOH on claudin-5 transcription and paracellular permeability. Furthermore, a novel finding in this study suggests that very low concentrations of AOs in tinctures such as Rooibos tea could profoundly alter the redox status of brain ECs.
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    Understanding human coronavirus HCoV-NL63
    (Bentham Science, 2010) Abdul-Rasool, Sahar; Fielding, Burtram C.
    Even though coronavirus infection of humans is not normally associated with severe diseases, the identification of the coronavirus responsible for the outbreak of severe acute respiratory syndrome showed that highly pathogenic coronaviruses can enter the human population. Shortly thereafter, in Holland in 2004, another novel human coronavirus (HCoV-NL63) was isolated from a seven-month old infant suffering from respiratory symptoms. This virus has subsequently been identified in various countries, indicating a worldwide distribution. HCoV-NL63 has been shown to infect mainly children and the immunocommpromised, who presented with either mild upper respiratory symptoms (cough, fever and rhinorrhoea) or more serious lower respiratory tract involvement such as bronchiolitis and croup, which was observed mainly in younger children. In fact, HCoV-NL63 is the aetiological agent for up to 10% of all respiratory diseases. This review summarizes recent findings of human coronavirus HCoV-NL63 infections, including isolation and identification, phylogeny and taxonomy, genome structure and transcriptional regulation, transmission and pathogenesis, and detection and diagnosis.