Medical Technology SA - Volume 26, Issue 1, 2012
Volume 26, Issue 1, 2012
Source: Medical Technology SA 26, pp 5 –8 (2012)More Less
Medical technologists participate in research projects conducted by doctors and scientists. They should be encouraged to carry out their own research projects. Using data that is routinely generated in one's own laboratory can minimise the need for additional resources. Information contained in the laboratory's information management system (LIMS) is primarily used as a management tool. It can be utilised as a source of research material. The LIMS can be used to pose and answer research questions. Displaying your laboratory's data in an annual report is a good starting point and displaying this data over time can be an important disease surveillance tool. The type of research that it is possible to carry out on data generated by the laboratory can be used to learn more about the utilisation of your services and improve the service offered by the laboratory. It may also be used to advance medical knowledge and carry out disease surveillance.
Examples from the authors' own experience in laboratory work are given.
Renal stone analysis : patient findings and Fourier Transform infrared spectroscopy method validation : peer reviewed original articleSource: Medical Technology SA 26, pp 9 –12 (2012)More Less
The aim of this study was to validate the Fourier Transform infrared spectroscopy (FTIR) method used for renal stone analysis, establish prevalence of renal stones and to obtain demographic information on patients presenting with renal stones. Renal stones are analyzed by FTIR to determine the constituents of the stones, in order to assist with the appropriate treatment of the patient and prevent a recurrence of stone formation. Validation of methods is important to ensure accurate reported results. The majority of the renal stones analyzed consisted of calcium in some form and the prevalence of stones was much higher in men (75%) than in women, which correlates to findings in other studies. The method is fit for the purpose of renal stone analysis using standard or mini pellets.
The predictive value of proBNP levels to determine the presence and severity of coronary artery disease in patients with a positive or inconclusive exercise stress test : peer reviewed original articleSource: Medical Technology SA 26, pp 13 –17 (2012)More Less
Background Several clinical studies have shown increased levels of N Terminal-Pronatriuretic Peptide (NT-proBNP) during episodes of coronory ischaemia. Consistent with this observation, both Brain Natriuretic Peptide (BNP) and NT-proBNP correlated to severity, location, and extent of angiographic coronary artery disease (CAD). The main objective of this study was to identify the possible value of NT-proBNP level which indicates CAD.
Methods Sixty patients with signs and symptoms of CAD were recruited for this study. They were divided into two groups; Group A, consisted of thirty patients with a positive Exercise Stress Test (EST) and Group B, consisted of thirty patients with an inconclusive EST. After the EST, all patients from both groups were required to have a NT-proBNP blood test, a left and right coronary angiogram and a left ventriculogram.
Results Post EST NT-proBNP levels, in both groups, increased in the presence of CAD (p<0.001). For the positive EST group, the area under the ROC curve was 0.975 (p<0.001). A cut-off value of 120 pg/ml was identified with the highest sensitivity (95.7%) and specificity (100%). For patients in the inconclusive EST group, the area under the ROC curve was 0.912 (p<0.001). A cut-off value of 85 pg/ml was identified with the highest sensitivity (87.5%) and specificity (86.4%).
Conclusion EST is relatively inaccurate at predicting CAD in patients with inconclusive ESTs. The need for an additional tool, such as NT-proBNP measurements post inconclusive EST is warranted in the determination of the presence of CAD.
Expression of p63, p504S and androgen receptor status in salivary gland carcinomas : a study of 32 cases : peer reviewed original articleSource: Medical Technology SA 26, pp 18 –21 (2012)More Less
Immunostaining for p63, p504S and the androgen receptor status are important markers for carcinomas of the prostate. The purpose of this study was to investigate the staining characteristics of these markers for malignancies of salivary gland origin. Wax blocks of 32 malignant salivary gland neoplasms were retrieved, sections prepared and stained by the H&E method and immunoperoxidase techniques for the demonstration of p63 (Dako N1604), p504S (Dako N1609) and androgen receptors (Dako M3562). The sections were viewed by light microscopy and positivity scored with the aid of a grading scale. Androgen receptor- and p504S positivity were infrequently observed in the study samples, except for salivary duct carcinoma and mucoepidermoid carcinoma where most of the cases stained positive for p504S. The staining pattern of adenoid cystic carcinomas for p63 correlated with the microscopic subtype. The basal- and intermediate cells of mucoepidermoid carcinomas stained positive- and the mucus- and epidermoid cells negative for p63. All acinic cell adenocarcinomas stained negative- and most clear cell carcinomas and epimyoepithelial carcinomas positive for p63. The role of these markers in the diagnosis and prognostication of malignancies of salivary gland origin is discussed.
Two year clinical outcomes after sirolimus-eluting stent implantation for the treatment of coronary artery disease : peer reviewed original articleSource: Medical Technology SA 26, pp 22 –27 (2012)More Less
Background Coronary artery stents are known to reduce rates of restenosis after coronary stenting, but it is uncertain how long this benefit is maintained. Clinical data has raised concerns that drug-eluting stents are associated with increased rates of late stent thrombosis, death or myocardial infarction.
Objectives To evaluate the safety and reliability of sirolimus-eluting stents in real-world practice out to two years.
Methods From January 2008 to June 2008, 30 patients were enrolled in the study after implantation of one or more sirolimus-eluting stents. We evaluated clinical follow-up information for up to two years after the implantation of Cypher® Select stents in 30 patients with 35 lesions.
Results Mean patient age was 62.33 +/- 10.99 years, 7 percent were diabetic and 30 percent presented with acute myocardial infarctions. The procedure's success rate was 100 percent for the sirolimus-eluting stent implantation, and follow-up rates were 100 percent. Mean total stent length was 22.32 +/- 6.63 mm, with 13 percent receiving more than one stent. Two year freedom from mortality, myocardial infarction, target vessel revascularization and stent thrombosis was 100 percent. Dual antiplatelet therapy was taken by 100 percent at 1 month, 53 percent at 6 months, 40 percent at 1 year and 0 percent of patients at 2 years. The rate of survival free of myocardial infarction, bypass surgery and repeated angioplasty for stented lesions was 100% at two years.
Conclusions Treatment of lesions with sirolimus-eluting stents is associated with a sustained clinical benefit two years after device implantation.
Collagen in odontogenic tumours : a histochemical- and immunohistochemical study of 19 cases : peer reviewed original articleSource: Medical Technology SA 26, pp 28 –33 (2012)More Less
This study investigated the collagen content of odontogenic tumours. Wax blocks of 19 odontogenic tumours (ameloblastoma n=3, adenomatoid odontogenic tumour n=3, ameloblastic fibroma n=3, ameloblastic fibro-odontoma and ameloblastic fibro-dentinoma n=4, odontogenic myxoma n=3 and odontogenic fibroma n=3) were sectioned and stained by the H&E-, Picrosirius-, Reticulin-, Masson Trichrome methods and the immunoperoxidase technique for collagen type IV. The distribution of collagen types I-IV was recorded for each tumour. The basement membrane zones of ameloblastomas showed perpendicular oriented collagen type I fibres which anastomosed with the stromal collagen. The collagen content correlated with the shapes of the epithelial components in ameloblastomas, adenomatoid odontogenic tumours, ameloblastic fibromas and odontogenic fibromas. Formation of collagen was found to be the first indication of stromal induction. In odontogenic myxomas, coarse type I collagen fibres were intersected at obtuse angles by delicate type III fibres. Except for around blood vessels, no collagen type IV was found in odontogenic tumours. The distribution of collagen is unique for each odontogenic tumour type.
Laser irradiation with 648 nm light stimulates autophagic human skin keratinocytes : peer reviewed original articleSource: Medical Technology SA 26, pp 34 –43 (2012)More Less
Background Laser phototherapy promotes cell viability, cell proliferation and migration. This study aimed to determine if laser irradiation could stimulate cellular responses of stressed cells to promote cell survival.
Materials and Methods Human keratinocytes were treated with 200 µM hydrogen peroxide (H2O2) or 0.4 µg/ml oligomycin to induce autophagy and 5% absolute ethanol (EtOH) or 12 µM tertbutylhydroperoxide (tBHP) to induce apoptosis (control). Cells were irradiated using 1.5 J/cm2 with 648 nm and cellular responses were measured after 1 h or after 24 h and 96 h at 37°C.
Results Irradiated cells treated with 200 µM H2O2 showed an increase in cell proliferation and decrease in intracellular calcium. Irradiated oligomycin treated cells showed a significant increase in intracellular calcium. Irradiated apoptotic (control) cells showed a decrease in ATP viability, an increase in cytotoxicity, decrease in intracellular Ca2+ and decrease in cell proliferation.
Conclusion Irradiated 200 µM H2O2 cells reverted to metabolically active, viable cells capable of proliferating within 96 h of laser irradiation. Changes in intracellular calcium following laser irradiation appear to influence cell survival and proliferation of stressed keratinocytes.
An audit of coagulation specimens requiring direct human involvement at an academic laboratory : peer reviewed original articleSource: Medical Technology SA 26, pp 44 –47 (2012)More Less
Introduction A trend exists towards automation in laboratory testing, including coagulation investigations. Some coagulation specimens cannot be summarily tested in fully automated systems because of suboptimal, pre-analytical factors that would influence results, while others require additional preparation prior to testing. The aim of this audit was to determine the proportion of coagulation specimens requiring direct human involvement for screening and additional sample preparation, and to analyse contributing factors.
Methods All specimens received for coagulation testing over a ten-month period were audited. Specimens requiring direct human involvement (screening for suboptimal, pre-analytical influences; double centrifugation) were recorded.
Results Of 8 614 specimens, 1 091 (12.7%) fell into one or more of the following categories: under-filled (2.9%); clotted (1.7%); incorrect specimen tubes (1.5%); lipaemic (0.1%); icteric (0.5%); haemolysed (0.9%); haematocrit >0.55 L/L (0.02%); old (1.9%); unlabelled or incorrectly labelled (0.2%); lupus anticoagulant (4.0%); activated protein-C resistance (0.1%). In total, 353 (4.1%) specimens required double centrifugation and 829 (9.6%) required screening.
Conclusion A substantial proportion of specimens required direct human involvement and would not have been suitable for coagulation testing in current fully automated systems.
Source: Medical Technology SA 26, pp 48 –52 (2012)More Less
Introduction Procalcitonin (PCT) is a biomarker used in the diagnosis and management of bacterial infection and sepsis. The BRAHMS Kryptor® PCT assay was the first automated assay on the market and was cleared by the FDA in 2008. Siemens and Roche Healthcare diagnostics have partnered with BRAHMS, and their automated PCT assays are now available in South Africa.
Aim and Methods The aim of this study was to compare different aspects of the Siemens ADVIA Centaur® PCT and Roche Elecsys® PCT assays with the existing BRAHMS Kryptor® PCT assay and to evaluate the analytical performance of the three different methods.
Results and Conclusion Although the three PCT assays differ in sample volume required, measuring range, dilution capacity and analysis time, the two new PCT methods from Siemens and Roche correlate well with the existing Kryptor PCT method.