Low light level in vitro monitoring of cellular and antigen-antibody reactions using a photon detection camera system — New perspectives for clinical diagnosis and research

Summary This article briefly describes the use of a photon counting system (ARGUS-100) in the detection of low levels of light. The ARGUS-100 was used in determining ATP in cell sections from tumor tissues and in measuring a luminescenceenhanced immunoluminometric assay, using ferritin as the analyte, based on the luminol-peroxide-4-iodophenol reaction with peroxidase as the enzyme. The aim is not so much the presentation of data, but rather to show the potentials of the photon counting camera in increasing our knowledge of the cellular and subcellular levels, as well as lowering the detection limits in already sensitive systems, such as immunoassays.Supported by the Bundesministerium für Forschung und Technologie (DFVLR grant No. 01Z08801)     

Plasmodium falciparum immunodetection in bone remains of members of the Renaissance Medici family (Florence, Italy, sixteenth century)

Medical accounts and ancient autopsy reports imply that tertian malarial fevers caused the death of four members of the Medici family of Florence: Eleonora of Toledo (1522-1562), Cardinal Giovanni (1543-1562), don Garzia (1547-1562) and Grand Duke Francesco I (1531-1587).All members of the Medici family hunted in the endemic malarial areas of Tuscany, such as the marshy areas surrounding their villas and along the swampy Maremma and were, therefore, highly exposed to the risk of being infected by Falciparum malaria. To determine if the original death certificates issued by the court physicians were correct, we carried out immunological investigations and then compared the biological results to the historical sources.Bone samples were examined for the presence of Plasmodium falciparum histidine-rich- protein-2 (PfHRP2) and P. falciparum lactate dehydrogenase (PfLDH) using two different qualitative double-antibody immunoassays.Our findings provide the first modern laboratory evidence of the presence of P. falciparum ancient proteins in the skeletal remains of four members of the Medici family. We confirm the clinical diagnosis of the court physicians, using modern methods.Finally, this study demonstrates that immunodetection can be successfully applied not only to mummified tissues but also to skeletal remains, thus opening new paths of investigation for large archaeological series.     

Comparison of five different immunoassays for the detection of Borrelia burgdorferi IgM and IgG antibodies

The performances of five commercially available enzyme immunoassays were compared for the detection of Borrelia burgdorferi IgM and IgG antibodies. Sensitivity was assessed with European serum samples collected from 45 patients with clinically defined Lyme disease in conjunction with a positive immunoblot (n = 44) or other serological test (n = 1). Sensitivities for the detection of IgM and IgG with each test were: Dako IgM 64%; Dako IgG 53%; Serion IgM 89%; and Serion IgG 88%. The Immunetics assay makes no distinction between IgM and IgG antibodies and had a sensitivity of 91%. Specificity was calculated by testing a control group comprising 40 patients with acute Epstein-Barr virus infection, cytomegalovirus infection, syphilis or rheumatoid factor positivity. The specificities achieved for each test were: Dako IgM 78%; Dako IgG 100%; Serion IgM 52%; Serion IgG 92%; and Immunetics 92%. The discriminatory power between control and patient samples appeared highest for the Immunetics assay. Between-run variation was comparable for the five tests and did not exceed 13%. When the Immunetics assay was used as an initial screening test, with low-titre positive results confirmed by an immunoblot, a sensitivity of 91% and a specificity of 100% were achieved. To attain maximal sensitivity, the Serion IgM and IgG tests were also performed on samples with negative Immunetics results. All positive Serion IgM and IgG results were also confirmed by immunoblot. In conclusion, the Immunetics assay, based on a synthetic C6 peptide, can be used reliably as an initial screening test for the serodiagnosis of Lyme disease.     

Highly-sensitive troponin I is increased in patients with gynecological cancers

Objectives

To investigate troponin I (TnI) in patients with gynecological cancers.

Methods

Highly-sensitive (HS) and conventional TnI were measured in 25 patients with untreated ovarian cancer, 25 with endometriosis and 25 with benign masses.

Results

Both HS and conventional TnI were increase in cancer patients. Values above the cut-off were found in 44% and 16% cancer patients using HS and conventional TnI methods, respectively.

Conclusions

Cardiac involvement is frequent in patients with gynecological cancers and should be preferably assessed using HS troponin immunoassays.     

Impact of atrial fibrillation on levels of high-sensitivity troponin I in a 75-year-old population

Abstract

Purpose. Atrial fibrillation (AF) has been associated with elevated levels of cardiac troponins; however, it is not clear if this association is independent of underlying cardiovascular disease. The aim of this study was to investigate the impact of AF on cardiac troponin I levels in a 75-year-old cohort from the general population, using a recently introduced, highly sensitive assay. Methods. All 75-year-old citizens in Asker and Baerum counties were invited to participate in a prevalence study of AF. High-sensitive troponin I (hs-TnI) levels were measured (Abbott Diagnostics) in serum samples collected from 62 subjects with AF and a gender-matched control group of 126 subjects in sinus rhythm. Results. Hs-TnI was detectable in all subjects (median 7.3 ng/L [range 3.0–88.7]). Patients with AF had higher levels than subjects in sinus rhythm (8.3 ng/L [3.7–88.7] vs. 6.8 ng/L [3.0–77.5]; p = 0.011). Male gender (p = 0.002), hypertension (p = 0.001), coronary heart disease (p < 0.001), heart failure (p < 0.001), prior stroke or transient ischemic attack (p = 0.013) and serum creatinine (p < 0.001) were all associated with higher levels of hs-TnI in univariate analysis. Heart failure and coronary heart disease remained significantly associated with hs-TnI in multivariate analysis, whereas the relation between AF and hs-TnI was no longer statistically significant. Conclusion. All subjects had detectable levels of hs-TnI. AF patients had higher hs-TnI levels than subjects in sinus rhythm; however, this difference was not statistically significant after adjustment for heart failure and coronary heart disease.     

利用Excel电子表格制作质控图在标记免疫室内质控中的应用

目的探讨利用Excel电子表格制作标记免疫室内质控图的方法。方法利用Excel的表格制作与函数计算功能,在单元格中输入室内质控数据,自动计算平均值(x)、标准差(s)和变异系数(CV%),利用图表制作功能,设计制作出包括失控点在内的单值多点的定量质控图。结果将质控数据输入数据表中,计算机可将所有的测定点绘制在一张质控图上,图中的失控点与在控点区分明显。结论对于没有实验室信息系统的基层实验室,及一些需要手工操作的放射免疫项目的实验室,室内质控图对保证检验结果的可靠性具有重要作用。     

Evaluating the Performance of Lateral Flow Devices for Total Aflatoxins with Special Emphasis on Their Robustness under Sub-Saharan Conditions

As aflatoxins are a global risk for humans and animals, testing methods for rapid on-site screening are increasingly needed alongside the standard analytical laboratory tools. In the presented study, lateral flow devices (LFDs) for rapid total aflatoxin screening were thoroughly investigated with respect to their matrix effects, cross-reactivity, their performance under harsh conditions in Sub-Saharan Africa (SSA), and their stability, as well as when compared with liquid chromatography-tandem mass spectrometry (LC-MS/MS). To analyze the matrix effects, qualitative test kits offering a certain cutoff level were used to screen different nut samples. In addition, these tests were challenged on their cross-reactivity with 230 fungal toxins and metabolites. Furthermore, the resulting measurements performed under harsh tropical conditions (up to 38.4 °C and 91% relative humidity) in SSA, specifically Burkina Faso and Mozambique, were compared with the results from a well-established and validated LC-MS/MS-based reference method. The comparison of the on-site LFD results with the reference method showed a good agreement: 86.4% agreement, 11.8% non-agreement, and 1.8% invalid test results. To test the robustness of the cutoff tests, short- and long-term stability testing was carried out in Mozambique and Nigeria. For both experiments, no loss of test performance could be determined. Finally, a subset of African corn samples was shipped to Austria and analyzed under laboratory conditions using semiquantitative aflatoxin tests. A good correlation was found between the rapid strip tests and the LC-MS/MS reference method. Overall, the evaluated LFDs showed satisfying results regarding their cross-reactivity, matrix effects, stability, and robustness.     

Comparison of the performance of enzyme immunoassays for hepatitis B and C detection in dried blood spot

Dried blood spots (DBSs) could be an alternative to serum for hepatitis B virus (HBV) and hepatitis C virus (HCV) diagnosis. This study aims to evaluate two enzyme immunoassays (EIAs) for HBsAg and anti-HCV detection using DBS. Serum was tested using commercial EIA. DBS was tested using optimized EIA developed for serum and commercial EIA developed for DBS (Imunoscreen). Concordances between DBS and serum samples for both markers and EIAs were higher than 97%. Both EIAs demonstrated good performance for HBsAg and anti-HCV detection using DBS, and these methods could be used unchangeably increasing the access for HBV and HCV diagnosis.