Live music reduces stress levels in very low-birthweight infants.

AIM: Music might benefit preterm infants in stressful, intensive care environments. However, data on stress level indicators, determined by salivary cortisol levels, are scarce. We evaluated the effect of live harp music on the stress level indicators of preterm infants in a neonatal intensive care unit (NICU). METHODS: We exposed 20 stable preterm infants to music for 15 min on three consecutive days. Saliva was collected before the music was played and 25 min and 4 h after it ended. Salivary cortisol levels were measured by liquid chromatography-tandem mass spectrometry and vital signs, oxygen saturation, bradycardia, apnoeas and oxygen desaturations were recorded. Pain levels were assessed by the Bernese Pain Scale for Neonates. RESULTS: Salivary cortisol was significantly lower 25 min (18.9 nmol/L [3.9-35.6] p = 0.001) and 4 h after music (17.4 nmol/L [3.9-35.3] p = 0.003) than at baseline 4 h before exposure (19.5 nmol/L [7.2-51.1]). After music, the number of apnoeas and oxygen desaturations was significantly reduced on all three, days and the number of bradycardia episodes on day one. Pain scores significantly improved after music on all 3 days. CONCLUSION: Exposure to live music reduced salivary cortisol and had beneficial effects on the physiologic parameters of stable preterm infants in a NICU.

A novel approach to signal normalisation in atmospheric pressure ionisation mass spectrometry.

The aim of our study was to test an alternative principle of signal normalisation in LC-MS/MS. During analyses, post column infusion of the target analyte is done via a T-piece, generating an "area under the analyte peak" (AUP). The ratio of peak area to AUP is assessed as assay response. Acceptable analytical performance of this principle was found for an exemplary analyte. Post-column infusion may allow normalisation of ion suppression not requiring any additional standard compound. This approach can be useful in situations where no appropriate compound is available for classical internal standardisation.

An on-line solid phase extraction procedure for the routine quantification of caspofungin by liquid chromatography-tandem mass spectrometry.

BACKGROUND: Extensive sets of data are required to investigate the potential use of a therapeutic drug monitoring with individualization of dosage of the antimycotic compound caspofungin. The goal was to develop an improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for this aim. METHODS: Following protein precipitation, on-line solid phase extraction was performed for sample preparation. As the internal standard compound the veterinary drug tylosin was used. A standard validation protocol was applied. RESULTS: Good reproducibility and accuracy of the method were observed. On-line solid phase extraction resulted in a convenient work-flow and good robustness of the method. CONCLUSIONS: This improved LC-MS/MS method was found reliable and convenient. It can be suggested for further work on the clinical pharmacology of caspofungin in the setting of clinical research laboratories.

Quantification of free serum cortisol based on equilibrium dialysis and isotope dilution-liquid chromatography-tandem mass spectrometry.

OBJECTIVES: Only unbound serum cortisol is bioactive and protein binding of cortisol is highly variable. Thus, the quantification of free serum cortisol (FSC) is of superior biological relevance compared to total serum cortisol quantification. Consequently, the development of automated routine tests for FSC for endocrine testing is desirable - along the lines of free thyroid hormone measurement. Since the availability of a reliable and matrix-independent method is an important tool for this goal, we have developed a highly standardised mass spectrometric FSC method. DESIGN AND METHODS: We used equilibrium dialysis (ED) to obtain a protein-free fraction from serum samples. The cortisol content of the dialysate was quantified using isotope-dilution two dimensional liquid chromatography (LCxLC-MS/MS). RESULTS: Comprehensive evaluation characterised the method as reliable and robust; using commercially available dialysis cells, convenient handling was realised. CONCLUSIONS: The method described in this article can be suggested for the implementation of a reference measurement system for FSC.

Relationship of a common polymorphism of the glucocorticoid receptor gene to traumatic memories and posttraumatic stress disorder in patients after intensive care therapy.

OBJECTIVE: Glucocorticoids play a major role in the consolidation and retrieval of traumatic information. They act through the glucocorticoid receptor, for which, in humans, several polymorphisms have been described. In particular, the BclI single-nucleotide polymorphism is associated with hypersensitivity to glucocorticoids and with susceptibility to development of major depression. Furthermore, in patients with posttraumatic stress disorder carrying the BclI GG genotype, cortisol levels were lower and showed an inverse relationship to posttraumatic stress disorder symptom intensity. Here, we studied the association of the BclI polymorphism with plasma cortisol levels, traumatic memories, posttraumatic stress disorder symptoms, and health-related quality of life outcomes in 126 patients undergoing cardiac surgery and intensive care unit therapy. DESIGN: Prospective observational study. SETTING: Cardiovascular intensive care unit in a university hospital. PATIENTS: A total of 126 patients undergoing cardiac surgery and intensive care unit treatment. INTERVENTIONS: No interventions were performed. MEASUREMENTS AND MAIN RESULTS: Validated questionnaires were used to quantify end points. Measurements were taken 1 day before and 1 wk and 6 months after cardiac surgery. Homozygous carriers of the BclI G allele (n = 21) had significantly lower preoperative plasma cortisol levels and more long-term traumatic memories from intensive care unit therapy at 6 months after cardiac surgery than heterozygous carriers or noncarriers (1.9 ± 1.4 vs. 1.0 ± 1.2, p = .01). Anxiety was significantly more common as a long-term traumatic memory in homozygous BclI G allele carriers than in heterozygous carriers or noncarriers (57% vs. 35%, p = .03). Posttraumatic stress disorder symptom scores were significantly higher at discharge from the intensive care unit in homozygous BclI G allele carriers than in heterozygous carriers or noncarriers. Only heterozygous carriers or BclI G allele noncarriers had a significant gain in health-related quality of life physical function at 6 months after cardiac surgery (p < .01). Baseline values were not statistically different between carriers of the different BclI alleles. CONCLUSION: Homozygous BclI G allele carriers are at risk for traumatic memories, posttraumatic stress disorder symptoms, and lower health-related quality of life after cardiac surgery and intensive care unit therapy. The BclI single-nucleotide polymorphism may help to identify individuals at need for tailored medical care.

Progress in automation of LC-MS in laboratory medicine.

BACKGROUND: LC-MS/MS is an almost universal technology for the quantification of small molecules in human sample materials. The widespread use of this technology in laboratory medicine is so far limited mainly by the extensive occupation of highly trained personnel which is required for method implementation and application. Furthermore, robustness of function and results is still a critical issue of routine quantitative applications of LC-MS/MS. CONTENT: This article reviews approaches to the automation of essential processes of LC-MS/MS applications in clinical laboratories. Furthermore, perspectives of further steps towards highly robust and fully automated LC-MS/MS methods and instrument configurations are discussed. CONCLUSIONS: There is a variety of efficient approaches to automation of LC-MS/MS methods in use which mainly address sample preparation. Such configurations allow a substantial increase of sample throughput and convenience when compared to standard protocols. However, these applications still have to be implemented for individual methods in heterogeneous instrument configurations and still require highly trained experts. Based on existing technologies, however, the development of fully automated LC-MS/MS front-end modules or MS/MS-based analyzers which offer a degree of user-friendliness and robustness similar to current standard clinical chemistry analyzers seems feasible today. Only such systems will make the entire analytical potential of LC-MS/MS amenable to clinical medicine also outside from tertiary care centres.

An on-line solid phase extraction procedure for the routine quantification of urinary methylmalonic acid by liquid chromatography-tandem mass spectrometry.

BACKGROUND: The goal of this study was to develop and to validate an improved isotope-dilution-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of methylmalonic acid (MMA) in urine. METHODS: A previously described sample preparation protocol requires two solvent extraction steps, including evaporation. The first extraction is to extract the analyte from the sample, and second occurs following derivatization of the extract. In the method described here, the second evaporation step was substituted by on-line solid phase extraction employing column-switching and a permanent co-polymer based extraction cartridge. A standard validation protocol was applied to investigate the performance of the method. RESULTS: The method was found to be linear in the clinically relevant range of concentrations (6-100 µmol/L). Total coefficients of variation were below 10% and inaccuracy was <10% for quality control samples at three concentrations. CONCLUSIONS: By omitting one evaporation step, the semi-automated method described in this article enables for more convenient work-flow in the quantification of urinary MMA compared to the previous protocol. This is of relevance for MMA measurement in the routine clinical laboratory setting. Validation demonstrated acceptable analytical performance.