Standard operation protocol for analysis of lipid hydroperoxides in human serum using a fully automated method based on solid-phase extraction and liquid chromatography-mass spectrometry in selected reaction monitoring

Review of the Use of Liquid Chromatography-Tandem Mass Spectrometry in Clinical Laboratories: Part I-Development

The process of method development for a diagnostic assay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) involves several disparate technologies and specialties. Additionally, method development details are typically not disclosed in journal publications. Method developers may need to search widely for pertinent information on their assay(s). This review summarizes the current practices and procedures in method development. Additionally, it probes aspects of method development that are generally not discussed, such as how exactly to calibrate an assay or where to place quality controls, using examples from the literature. This review intends to provide a comprehensive resource and induce critical thinking around the experiments for and execution of developing a clinically meaningful LC-MS/MS assay.

Influence of endodontic treatment on systemic oxidative stress

INTRODUCTION

An increased production of oxidizing species related to reactive oral diseases, such as chronic apical periodontitis, could have systemic implications such as an increase in cardiovascular morbidity. Based on this consideration, we conducted a prospective study to assess whether subjects affected by chronic periodontitis presented with higher values of oxidative stress than reference values before endodontic treatment, and whether endodontic treatment can reduce the oxidative imbalance and bring it back to normal in these subjects.

MATERIALS AND METHODS

The authors recruited 2 groups of patients from private studies and dental clinics: these patients were recruited randomly. The oxidative balance in both patients with chronic apical periodontitis (CAP) and healthy control patients was determined by measuring the oxidant status, using an identification of the reactive oxygen metabolites (d-ROMs) test, while the antioxidant status in these patients was determined using a biological antioxidant potential (BAP) test. Both these tests were carried on plasma samples taken from enrolled patients. Values were measured both before the endodontic treatment of the patients with chronic apical periodontitis, and 30 and 90 days after treatment, and compared to those obtained from healthy control patients.

RESULTS

It was found that, on recruitment, the patients with chronic apical periodontitis exhibited significantly higher levels of oxidative stress than control patients, as determined by the d-ROMs and BAP tests. Furthermore, the d-ROMs test values were shown to decrease and the BAP test values to increase over time in patients with chronic apical periodontitis following endodontic therapy. As the levels of oxidative stress in these patients tended to reduce and return to normal by 90 days following treatment.

CONCLUSIONS

This study has demonstrated a positive association between chronic apical periodontitis and oxidative stress. Subjects affected by chronic apical periodontitis are exposed to a condition of oxidative stress, which is extremely dangerous to general health. Moreover, one can infer from these findings that through proper endodontic therapy, a good oxidative balance can be restored, thereby avoiding the risk of contracting the abovementioned diseases.

Collaborative study to establish a proficiency panel of hepatitis B surface antigens for evaluating in vitro diagnostics

Hepatitis B virus (HBV) infection is a critical health issue. In hospitals, in vitro diagnostic devices (IVDs) are used to detect HBV infections. The Taiwan Food and Drug Administration has prepared a candidate hepatitis B surface antigen (HBsAg) proficiency panel as an analytical standard to evaluate the sensitivity of the postmarketing surveillance of HBV IVDs. The sensitivity and stability of the proficiency panel, which comprises 5 HBsAg positive sera (SN-A to E) and 1 negative serum, was determined by a collaborative study involving 8 collaboratories. The potency of the candidate proficiency panel was consistent among all collaboratories. The potencies of sera SN-A to E in semiquantitative and quantitative analyses were 2.823-0.011 and 2.229-0.009 IU/mL, respectively. The mean coefficients of variation (CV) of intra and interday precision among the collaboratories were <7%. Accelerated degradation and long-term storage tests were used as stability assays. The candidate HBsAg proficiency panel exhibited good stability under different storage conditions, while all CVs were <6%. In conclusion, this candidate HBsAg proficiency panel is credible and reliable. Therefore, it can be used for postmarketing surveillance of HBV IVDs and quality assessment by clinical researchers and IVD manufacturers.

Antioxidative defense and oxidative stress in ringed seals (Pusa hispida) from differently polluted areas

High contaminant levels detected in Baltic seals have been associated with various health effects. In this study several parameters related to antioxidative defense and oxidative stress (concentrations of reduced and oxidised glutathione, lipid hydroperoxide and vitamin E, activities of glutathione reductase, peroxidase and S-transferase, glucose-6-phosphate dehydrogenase, catalase, and superoxidedismutase) were measured in the livers of ringed seals from the Baltic Sea and from a less contaminated reference area, Svalbard, Norway. Seals were caught during two different time periods 1996-1997 and 2002-2007, which represent different levels of contamination. No signs of oxidative damage were found in the Baltic seals. However, glutathione metabolism was enhanced in the ringed seals from the Baltic Sea compared to the seals from Svalbard. The adaptation to dive where repetitive ischemia/reperfusion occurs naturally may contribute to the resistance of oxidative stress and to the capacity to increase enzymatic antioxidant defense in phocid seals. This could explain the similarities in oxidative stress levels despite the differences in antioxidant responses between the ringed seals from the Baltic Sea and Svalbard.