Siektes van peroksisome - 'n oorsig

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Ultrastructural localisation of iron in the jejunum of black children with pellagra

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The knowledge, awareness and practices of radiation safety amongst orthopaedic surgeons

BACKGROUND : Fluoroscopic imaging in orthopaedic theatres is increasing, with added risk to the orthopaedic surgeon who is increasingly being exposed to ionising radiation. It is thus crucial for orthopaedic surgeons to have a working knowledge of radiation safety. In spite of these concerns, however, many orthopaedic surgeons do not receive standard training in radiation safety. OBJECTIVES : The evaluation of orthopaedic surgeons’ knowledge, awareness and everyday practices regarding radiation safety in an academic hospital. METHODS : A questionnaire with multiple-choice-type questions was developed by a panel of experts and used to conduct a descriptive study. The questionnaire had multiple dimensions, each evaluating orthopaedic knowledge, awareness and practices, respectively. The study population included orthopaedic surgeons rotating within the orthopaedic circuit of the University of Pretoria. RESULTS : Orthopaedic surgeons regularly make use of fluoroscopic imaging in theatre, with 34 (77%) participants indicating that they use fluoroscopy in more than half of all their procedures performed. Most participants have insufficient knowledge of radiation safety, with the majority failing to correctly answer basic questions on radiation safety. Forty (91%) participants do not wear personal dosimeters, in spite of 39 participants (89%) believing that they are vulnerable to adverse effects. Basic radiation protection devices are underutilised, with 32 (73%) participants indicating that they have not received adequate training in radiation safety. CONCLUSION : The majority of orthopaedic surgeons regularly use fluoroscopic imaging in theatre yet lack in-depth knowledge and awareness regarding radiation safety associated with this imaging modality. Implementation of a radiation safety training programme is thus recommended.Dissertation was completed at the University of Pretoria:http://www.sajr.org.zaam2021Radiolog

Migraine-associated vertigo and dizziness as presenting complaint in a private general medical practice

Migraine-associated vertigo (MV) remains a developing entity because accepted diagnostic criteria are unavailable. Patients present with debilitating dizziness without experiencing headache, and are often misdiagnosed as anxious. The condition is manageable in primary care without the need for neurological referral. The aim of this study was to investigate the prevalence of MV and migraine-associated dizziness (MD) as presenting complaints. Methods: Patients presented with dizziness probably or definitely associated with migraine history based on the criteria of the International Headache Society. Patients with other vestibulopathies and medical conditions were excluded. Patients were evaluated over a period of nine months. Seven hundred and seventeen patients were examined. The numbers of patients were recorded as a percentage of the population visiting a general practitioner. Response to migraine prophylactic medications was regarded as supporting evidence of the diagnosis. Response was regarded as a complete resolution of symptoms. Results: Of the 717 patients seen, 12 were identified as having probable or definite MV. Five patients were treated with migraine prophylactic medications, namely amitriptyline 25 mg nocte and/or sodium valproate CR 300 mg bd, and all showed a response to the treatment. Conclusions: We conclude that the prevalence of MV as presenting complaint may be as high as 1.67%. This figure does however not reflect the total patient population that suffers from the condition – this figure may be much higher. Of those patients treated for MV the response was 100%, further supporting the diagnosis. MV is a relevant complaint that is often misdiagnosed as psychogenic in origin

Estrogens and genomic instability in human cancer cells-involvement of Src/Raf/Erk signaling in micronucleus formation by estrogenic chemicals

This article is available open access through the publisher’s website. Copyright @ 2008 The Authors.Reports of the ability of estrogenic agents such as 17β-estradiol (E2), estriol (E3) and bisphenol A (BPA) to induce micronuclei (MN) in MCF-7 breast cancer cells have prompted us to investigate whether these effects are linked to activation of the estrogen receptor (ER) α. Coadministration of tamoxifen and the pure ER antagonist ICI 182 780 to cells treated with E2 and E3 did not lead to significant reductions in micronucleus frequencies. Since these antiestrogens interfere with the transcriptional activity of the ER and block promotion of ER-dependent gene expression, it appears that this process is not involved in micronucleus formation. However, ER activation also triggers rapid signaling via the Src/Raf/extracellular signal-regulated kinase (Erk) pathway. When MCF-7 cells were exposed to E2 and BPA in combination with the specific kinase inhibitors pyrazolopyrimidine and 2′-amino-3′-methoxyflavone, reductions in micronucleus frequencies occurred. These findings suggest that the Src/Raf/Erk pathway plays a role in micronucleus formation by estrogenic agents. Enhanced activation of the Src/Raf/Erk cascade disturbs the localization of Aurora B kinase to kinetochores, leading to a defective spindle checkpoint with chromosome malsegregation. Using antikinetochore CREST antibody staining, a high proportion of micronucleus containing kinetochores was observed, indicating that such processes are relevant to the induction of MN by estrogens. Our results suggest that estrogens induce MN by causing improper chromosome segregation, possibly by interfering with kinase signaling that controls the spindle checkpoint, or by inducing centrosome amplification. Our findings may have some relevance in explaining the effects of estrogens in the later stages of breast carcinogenesis.European Commissio

In vitro osteoclast-like and osteoblast cells' response to electrospun calcium phosphate biphasic candidate scaffolds for bone tissue engineering

Successful long term bone replacement and repair remain a challenge today. Nanotechnology has makes it possible to alter materials’ characteristics and therefore possibly improve on the material itself. In this study, biphasic (hydroxyapatite/β-tricalcium phosphate (HA/β-TCP)) nanobioceramic scaffolds were prepared by the electrospinning technique in order to mimic the extracellular matrix (ECM). Scaffolds were characterised by scanning electron microscopy (SEM) and Attentuated Total Reflectance Fourier Transform Infrared (ATRFTIR). Osteoblasts as well as monocytes that were differentiated into osteoclast-like cells, were cultured separately on the biphasic bioceramic scaffolds for up to 6 days and the proliferation, adhesion and cellular response were determined using lactate dehydrogenase (LDH) cytotoxicity assay, nucleus and cytoskeleton dynamics, analysis of the cell cycle progression, measurement of the mitochondrial membrane potential and the detection of phosphatidylserine expression. SEM analysis of the biphasic bioceramic scaffolds revealed nano fibers spun in a mesh-like scaffold. Results indicate that the biphasic bioceramic electrospun scaffolds are biocompatible and have no significant negative effects on either osteoblasts or osteoclast-like cells in vitro.Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa.http://www.springer.com/materials/journal/10853hb201

HFOB 1.19 osteoblast cells grown on a biomimetic biphasic nanoscaffold : an in vitro evaluation for possible bone tissue engineering

Much research over the past five decades has focussed on the repair and replacement of bone. Recently, the research focus has shifted to nanotechnology since it provides a platform from which to alter and possibly improve materials’ properties. In this study we have made use of previously developed electrospun biphasic nanoscaffolds to culture osteoblast cells on, and investigate specific responses of the cells towards the scaffolds. Osteoclast-like cells and osteoblast cells were cultured separately on the nanoscaffolds and the proliferation, adhesion and cellular response were determined. In this study, the mineralisation of the osteoblast cells was observed in a time study. The intracellular calcium ion concentration and nitric oxide concentration were determined in vitro while the cells were proliferating on the scaffolds. The expression of endothelial and inducible nitric oxide synthase was determined immunohistochemically. Quantitative data were obtained from fluorometer studies. Qualitative data was supplied by light- and fluorescent confocal microscopy. During studies with microscopy, a minimum of five representative images from each sample were captured. The cells showed increased mineralisation over time. An increase in intracellular Ca2+ was not observed when compared to the controls. However, an increase in intracellular nitric oxide formation was detected. Expression of endothelial nitric oxide synthase but not inducible nitric oxide synthase was detected in vitro. From the results we can conclude that the scaffolds are biocompatible and conducive to healthy cell growth and differentiation and could possibly be applied in non-load-bearing bone regeneration and repair applications.http://www.biomedres.infoam2019Physiolog

The in vitro effects of a sulphamoylated derivative of 2-methoxyestradiol on cell number, morphology and alpha-tubulin disruption in cervical adenocarcinoma (HeLa) cells

2-Methoxyestradiol (2ME2) is an endogenous metabolite of estrogen that has both antiangiogenic and antitumor effects. However, the shortcoming with 2ME2 is that it is rapidly inactivated by 17β-hydroxysteroid dehydrogenase type 2. Thus a bis-sulphamoylated derivative of 2ME2, 2-Methoxyestradiol-bis-sulphamate (2MEBM) was synthesized in order to address the shortcoming of 2ME2. The aim of this in vitro study was to investigate the influence of 2MEBM on cell growth, morphology and tubulin structure in a cervical cancer (HeLa) cell line. Dose-dependent studies revealed that 0.55μM of 2MEBM inhibited cell growth by 50%. 2MEBM-treated cells showed an increase in the number of metaphase cells, apoptotic cells, and disrupted tubulin structure after 48 hours of exposure to 0.55μM of 2MEBM. Future studies will be conducted to further investigate the mechanism of action of 2MEBM in cervical carcinoma cells.Grants from the Cancer Association of South Africa (AK246), the Medical Research Council (AG374, AK076), National Research Foundation and Struwig Germishuysen Trust (AJ038).http://www.jstage.jst.go.jp/browse/biomedre

Changes in red blood cell membrane structure in type 2 diabetes : a scanning electron and atomic force microscopy study

Red blood cells (RBCs) are highly deformable and possess a robust membrane that can withstand shear force. Previous research showed that in diabetic patients, there is a changed RBC ultrastructure, where these cells are elongated and twist around spontaneously formed fibrin fibers. These changes may impact erythrocyte function. Ultrastructural analysis of RBCs in inflammatory and degenerative diseases can no longer be ignored and should form a fundamental research tool in clinical studies. Consequently, we investigated the membrane roughness and ultrastructural changes in type 2 diabetes. Atomic force microscopy (AFM) was used to study membrane roughness and we correlate this with scanning electron microscopy (SEM) to compare results of both the techniques with the RBCs of healthy individuals. We show that the combined AFM and SEM analyses of RBCs give valuable information about the disease status of patients with diabetes. Effectiveness of treatment regimes on the integrity, cell shape and roughness of RBCs may be tracked, as this cell’s health status is crucial to the overall wellness of the diabetic patient.http://cardiab.biomedcentral.comam2016Physiolog