Medical Technology SA - Volume 29, Issue 2, 2015
Volume 29, Issue 2, 2015
Author H.D. MiniggioSource: Medical Technology SA 29, pp 5 –8 (2015)More Less
As allied healthcare professionals, medical laboratory technologists are an integral part of the healthcare team, tasked with carrying out essential technical and scientific services in the laboratory. These key technical and scientific resources aid the pathologist and/or clinician in attaining an accurate diagnosis and hence providing the appropriate treatment. In South Africa, pathology services represent an integral part of the clinical consultation and most healthcare diagnosis and treatment involves these services, which are thus fundamental to current healthcare practices. Medical laboratory technologists practice their profession guided by ethical codes and high ethical standards are expected of them. This manuscript explains the four principles of bioethics as they apply to the profession of medical laboratory technology and describes the principles of professionalism for medical laboratory technologists in regard to the social responsibility and the importance of the professional and also the moral contract between society and the profession.
Important information regarding the two issues of December 2014 (Vol 28 No 2 (2014)) and June 2015 (Vol 29 No 1 (2015))Source: Medical Technology SA 29 (2015)More Less
The SMLTSA apologises to all who have eagerly awaited the two issues of December 2014 (Vol 28 No 2 (2014)) and June 2015 (Vol 29 No 1 (2015)). We also thank the authors, who submitted articles for peer review and publication for their patience and understanding. Therefore please note that these issues will not be published.
Source: Medical Technology SA 29, pp 9 –12 (2015)More Less
Background: The variability in CD4+ cell counts within mothers and babies at birth, in human immunodeficiency virus (HIV) positive mothers, has not been explained adequately. As one of the predictors of HIV, the CD4+ cell count plots the course of HIV progression. The important implication has to be understood, in relation to HIV-related opportunistic infections. Therefore, this study proposes to evaluate factors that determine CD4+ cell count in infants born to women infected with HIV and to determine the relationship between CD4+ cell counts in maternal viraemia and CD4+ cell counts of babies at birth.
Methods: A semi-parametric approach was used in modeling CD4+ cell counts in the newly born babies to HIV-positive women. Gestational age of the mothers was including in the model using a smooth function to cater for non-linearity. Analysis was restricted to antiretroviral therapy (ART) - naive, HIV-infected pregnant women. At enrollment, maternal median age was 26 years (interquartile range (IQR): 5) and median CD4+ counts was 459 cells/mm3 (IQR: 566). The mean (SD) CD4+ cell counts of HIV-seropositive women were 691 cells/mm3 (803 cells/mm3).
Results: Maternal CD4+ counts and gestational age were found to be the significant determinants of CD4+ counts in the new born babies. Maternal CD4+ was positively associated with CD4+ counts in babies (0.239; p=0.004). We noted a non-linear trend in CD4+ cell activity with gestational age, the optimum value at occurs at 37 weeks of pregnancy.
Conclusions: The model provides a flexible way to estimate the changing distribution of CD4+ cell counts in babies with weeks of pregnancy. Results obtained from the semi-parametric modeling could substantially improve the planning of health services, including the need for antiretroviral therapy.
Source: Medical Technology SA 29, pp 13 –19 (2015)More Less
Nanotechnology is a promising arena for generating new applications in medicine. It is advancing rapidly due to the great progress achieved in various fileds including electronics, mechanics, cosmetics, food, etc. In order to successfully bifunctionalise nanoparticles for a given biomedical application, a wide range of chemical, physical and biological factors have to be taken into account. Silver nanoparticles (AgNPs) exhibit strong antibacterial activity owing to their large surface to volume ratios and crystallographic surface structure. Nanosilver particles have been widely used in a range of biomedical applications including diagnosis, treatment, medical device coatings, drug delivery and personal health care products. With the growing application of nanosilver particles in medical contexts, it is becoming necessary for a better understanding the mechanisms of action, biological interactions and their potential toxicity on exposure. This review aims to provide critical assessment of the current understanding of antibacterial activity, biomedical applications and toxicity of silver nanoparticles.
A review of the photodynamic application of 5-aminolevulinic acid, Hypericin and phthalocyanines in dermatology : reviewSource: Medical Technology SA 29, pp 20 –26 (2015)More Less
Ultraviolet radiation can damage human skin leading to photo-aging and cancer. Treatment options for skin cancers are available. Amongst them, there is photodynamic therapy (PDT), the treatment modality that involves a photochemical reaction between a light sensitive compound, visible light and tissue oxygen. In PDT, a photosensitive compound also called photosensitizer (PS) is administered and allowed to accumulate in the cancerous tissue then irradiated with light corresponding to absorption wavelength of the PS, in the presence of molecular oxygen, to produce cytotoxic species that kill the cancerous tissue. PDT is increasingly used and studied globally for the treatment of different classes of cancers because of its selective destruction of diseased tissue or cancer. Newly developed non-invasive imaging technologies including photodynamic diagnosis, may assist with early identification of skin cancer to reduce the rates of morbidity and mortality following treatment. Photodynamic diagnosis (PDD) is a diagnostic modality defined from the PDT principle. It utilizes light and fluorescent PS to highlight tumour cells from normal cells. Excitation of PS by appropriate light source causes them to fluoresce over well-defined spectral regions. Therefore, the fluorescent properties of PSs can serve as an important diagnostic tool to highlight cancer at an early stage of development. In this review, our knowledge about PDT and PDD of skin cancers using 5-aminolevulinic acid (ALA), Hypericin and phthalocyanines as photosensitizers is presented.
Source: Medical Technology SA 29, pp 27 –30 (2015)More Less
Background: The one-stage factor VIII (FVIII) assay is the most widely used assay for the quantification of FVIII. Several disadvantages of the one-stage assay have been described. The two-stage- and chromogenic FVIII assays purportedly overcame these disadvantages. The chromogenic method is easier to automate and the reagents are readily available. In this evaluation we evaluated the chromogenic FVIII assay on the Sysmex CS 2100i instrument.
Methods: We compared the FVIII levels of healthy individuals and haemophilia A patients, as determined by the one-stage and chromogenic FVIII assays, respectively.
Results: FVIII levels differed significantly between assays. The lower FVIII detection limit of both assays did not allow the quantification of FVIII for the haemophilia A patients. The addition of heparin led to a decrease in FVIII levels detected by the one-stage FVIII assay, but did not affect the chromogenic assay results.
Conclusion: The chromogenic FVIII assay can be introduced into the diagnostic laboratory as part of haemophilia A diagnosis and monitoring. However, the one-stage FVIII assay is still recommended as the first-line screening test as it had a lower FVIII detection limit and was more cost effective.
A comparison of animal haemoglobins using high-performance liquid chromatography (HPL C) : scientific reportSource: Medical Technology SA 29, pp 31 –40 (2015)More Less
Automated cation-exchange HPLC is now considered the cornerstone diagnostic method in many laboratories for two reasons.
Firstly, unlike other methodologies it detects variant haemoglobins and measures haemoglobin's A, A2 and F percentages in a single procedure.
Secondly it is suitable for larger workloads in that it is now fully automated.
Haemoglobin is most generally characterised as consisting of two α and two non-α dimers that couple to form a tetramer in certain physiological conditions. This with its own haem group in a 'pocket' is then formed to make up a haemoglobin molecule.
This study was undertaken in order to document these different animal haemoglobins using HPLC in samples obtained from animal species in both the Kruger National Park and the Pretoria Zoo, with the proviso of setting up a comprehensive atlas of these particular animal haemoglobins, which could be used in a clinical diagnostic setting.
HPLC analysis was carried out on the following adult species:
Gorilla, chimpanzee, chacma baboon, vervet monkey, lion, leopard, white rhino, giraffe, wild dog, buffalo, blue and black wildebeest, Nile crocodile, eland, pigmy hippopotamus and cheetah. The findings indicated that each species had its own unique chromatogram when compared to that of humans, with regards to:Retention times (i.e. the time from application to elution from the column), their characteristic percentage and in some cases, in the shape of the peak or curve produced.
Analysis of these animal haemoglobins produced chromatograms with three or more significant peaks. Mostly these peaks corresponded to the α-globin chain, the β-globin chain and the haem unit. As confirmed in previous studies there were some species that had as many as four distinct chromatographic peaks.
The retention times produced from the 17 animal species examined in this study can then serve as profiles, which could be used to compile a comprehensive atlas of their unique haemoglobin chromatograms. It could also be used to identify each species where each has its own unique chromatogram. This atlas, similar to that compiled for the human haemoglobins could then be used in a clinical setting where abnormalities in the HPLC retention times may be detected if the animal is in any way compromised.