Direct analysis of sterols from dried plasma/blood spots by an atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) method for a rapid screening of Smith-Lemli-Opitz syndrome.

Here is proposed a rapid and sensitive method involving atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) for specific laboratory screening of the Smith– Lemli–Opitz syndrome (SLOS), an inherited defect of cholesterol biosynthesis. Biochemical findings in the blood of SLOS patients are low cholesterol (Chol), high 7- and 8-dehydrocholesterol (DHCs) levels and high DHCs/Chol ratios. The APTDCI proposed method is able to ionize sterols for qualitative and quantitative analysis directly from dried plasma/blood spots. Critical APTDCI parameters – desolvation gas flow and temperature – were optimized analyzing Chol, 7-DHC and cholesteryl stearate standards spotted onto a glass slide acquiring the full scan spectra in positive ion mode. Chol levels in dried plasma spots of unaffected controls (n ¼ 23) obtained by the proposed method were compared with those of the enzymatic method (y ¼ 0.9166x + 0.3811; r ¼ 0.8831) while Chol and DHCs of SLOS patients (n ¼ 9) were compared with the gas chromatography flame ionization detection (GC-FID) method (y ¼ 0.8214x + 0.7388; r ¼ 0.8288). The APTDCI-MS method is also able to differentiate normal from SLOS samples directly analyzing whole blood and washed red cells spotted on paper. In conclusion, the intrinsic analytical high-throughput of APTDCI-MS method for sterol analysis could be useful to screen SLO syndrome

A radiation free alternative to CBCT volumetric rendering for soft tissue evaluation

Objective: The aim of the present study is to evaluate whether a “radiation free” method using 3D facial scan can replace Cone Beam Computed Tomography (CBCT) volumetric rendering of soft tissue of the patient to assess maxillofacial surgery outcomes and compare the reference points and angular measurements of patient facial soft tissue. Material and Methods: Facial soft tissue scan of the patient’s face, before and after orthognathic surgery and a CBCT of the skull for volumetric rendering of soft tissues were carried out. The 3D acquisitions were processed using Planmeca ProMax 3D ProFace® software (Planmeca USA, Inc.; Roselle, Illinois, USA). The participant were positioned in a natural position during the skull scannering. Three sagittal angular measurements were performed (Tr-NA, Tr-N-Pg, Ss-N-Pg) and two verticals (Go-N-Me, Tr-Or-Pg) on facial soft tissue scan and on the patient’s 3D soft tissue CBCT volumetric rendering. Results: A certain correspondence has been demonstrated between the measurements obtained on the Proface and those on the CBCT. Conclusion: A radiation free method was to be considered an important diagnostic tool that works in conditions of not subjecting the patient to harmful ionizing radiation and it was therefore particularly suitable for growing subjects. The soft tissue analysis based on the realistic facial scan has shown sufficient reliability and reproducibility even if further studies are needed to confirm the research result

Plasma levels of conjugated bile acids in newborns after a short period of parenteral nutrition.

Background: Patients receiving parenteral nutrition (PN) frequently exhibit liver dysfunction. The authors previously reported that plant sterols of lipid emulsions added to the nutritional solution of newborns receiving PN accumulate in plasma and cell membranes and may contribute to the development of cholestasis. Conjugated bile acids (BA) have been shown to be useful markers of cholestasis. Plasma levels of several BA in newborns were quantified after administration of PN for less than 2 weeks. Methods: Plasma samples from 15 healthy control infants (CN), 22 patients who had received PN for 3-15 days (T1), and 9 patients scheduled to receive PN (T0) were analyzed. After a simple extraction procedure, plasma BA were analyzed by liquid chromatography-tandem mass spectrometry using a quantitative isotope dilution method. Results: The concentrations of BA did not differ significantly between controls and patients before PN (CN vs T0), with the exception of glycocholic acid (GCA; 2.30 ± 2.60 ??M vs 7.29 ± 5.39 ??M, respectively). There was a significant difference in several BA between controls and patients after PN (2.30 ± 2.60 ??M vs 7.61 ± 6.46 ??M for GCA, respectively; 4.02 ± 3.49 ??M vs 11.88 ± 11.05 ??M for taurocholic acid [TCA], respectively; and 4.81 ± 3.49 ??M vs 13.58 ± 12.22 ??M for taurochenodeoxycholic + taurodeoxycholic + tauroursodeoxycholic acids [TCDCA+TDCA+TUDCA], respectively). Conclusions: In newborns receiving PN, a short period of PN is associated with an early increase of some conjugated BA. These results suggest that GCA, TCA, and TCDCA+TDCA+TUDCA levels could be used as early markers of PN-related cholestasis

Characterization of pigments and ligands in a wall painting fragment from Liternum archaeological park (Italy).

Spectroscopic and MS techniques were used to characterize the pigments and the composition of polar and nonpolar binders of a stray wall painting fragment from Liternum (Italy) archaeological excavation. X-ray fluorescence and diffraction analysis of the decorations indicated mainly the presence of calcite, quartz, hematite, cinnabar, and cuprorivaite. Infrared spectroscopy, GC coupled to flame-ionization detector, and MS analysis of the polar and nonpolar components extracted from paint layers from three different color regions revealed the presence of free amino acids, sugars, and fatty acids. Interestingly, LC-MS shotgun analysis of the red painting region showed the presence of αS1-casein of buffalo origin. Compared to our previous results from Pompeii's wall paintings, even though the Liternum painting mixture contained also binders of animal origin, the data strongly suggest that in both cases a tempera painting technique was utilized

Precursor ion scan profiles of acylcarnitines by atmospheric pressure thermal desorption chemical ionization tandem mass spectrometry.

The fatty acyl esters of L-carnitine (acylcarnitines) are useful biomarkers for the diagnosis of some inborn errors of metabolism analyzed by liquid chromatography/tandem mass spectrometry. In this study the acylcarnitines were analyzed by atmospheric pressure thermal desorption chemical ionization using a commercial tandem mass spectrometer (APTDCI-MS/MS). The method is based on the precursor ion scan mode determination of underivatized acylcarnitines desorbed from samples by a hot desolvation gas flow and ionized by a corona pin discharge. During desorption/ionization step the temperature induces the degradation of acylcarnitines; nevertheless, the common fragment to. all acylcarnitines [MH-59](+) is useful for analyzing their profile. APTDCI parameters, including angle of collection and incidence, gas flows and temperatures, were optimized for acylcarnitines. The experiments were performed drying 2 mu L of an equimolar mixture of acylcarnitine standards on a glass slide. The specificity was evaluated by comparing product ion spectra and the precursor ion spectra of 85 m/z of acylcarnitines obtained by the APTDCI method and by electrospray ionization flow injection analysis (ESI-FIA). The method was also employed to analyze acylcarnitines extracted from a pathological dried blood spot and a control. The method enables analysis of biological samples and recognition of some acylcarnitines that are diagnostic markers of inherited metabolic diseases. The intrinsic high-throughput analysis of the ambient desorption ionization methods offers a new opportunity either for its potential application in clinical chemistry and for the expanded screening of some inborn errors of metabolism. Copyright (C) 2008 John Wiley & Sons, Ltd

Evaluation of mobile phase, ion pairing, and temperature influence on an HILIC-MS/MS method for L-arginine and its dimethylated derivatives detection.

Asymmetric NG,–NG-dimethylarginine (ADMA) increases in diseases such as renal failure, diabetes mellitus, and hypercholesterolemia. The feasibility and utility of a hydrophilic interaction chromatography (HILIC) method for the separation of free Larginine (Arg), ADMA, and symmetric NG,–NG9-dimethylarginine (SDMA) on a typical silica column were explored and the impact of some experimental parameters on the chromatographic behavior of these analytes was investigated. The effect of water and TFA content in mobile phase and of column temperature was investigated during the development of a fast and simple HILIC-MS/MS method that might be suitable for the quantification of free Arg, ADMA, and SDMA in plasma for routine analysis. Our results show that a good compromise between efficiency and peak shape with acceptable retention and total chromatographic run time is achieved using an ACN/water (90:10) mobile phase with TFA% as additive ranging from 0.015 to 0.025% and column temperature ranging from 25 to....

Profiling of acylcarnitines and sterols from dried blood or plasma spot by atmospheric pressure thermal desorption chemical ionization (APTDCI) tandem mass spectrometry

Free carnitine and acylcarnitines play an important role in the metabolism of fatty acids. Sterols are structural lipids found in themembranes ofmany eukaryotic cells, and they also have functional roles such as the regulation of membrane permeability and fluidity, activity of membrane-bound enzymes and signals transduction. Abnormal profiles of these compounds in biological fluids may be useful markers of metabolic changes. In this review,we describe the subset of the lipidome represented by acylcarnitines and sterols, andwe summarize how these compounds have been analyzed in the past. Over the last 50 years, lipid mass spectrometry (MS) has evolved to become one of the most useful techniques for metabolic analysis. Today, the introduction of new ambient ionization techniques coupled to MS (AMS), which are characterized by the direct desorbing/ionizing of molecules from solid samples, is generating new possibilities for in situ analysis. Recently, we developed an AMS approach called APTDCI to desorb/ionize using a heated gas flow and an electrical discharge to directly analyze sterols and indirectly investigate acylcarnitines in dried blood or plasma spot samples. Here, we also describe the APTDCI method and some of its clinical applications, and we underline the common complications and issues that remain to be resolved. This article is part of a Special Issue entitled: Lipodomics and ImagingMass Spectrometry