A simple method modification to increase separation of 2- and 3-hydroxyglutaric acid by GC-MS for clinical urine organic acids analysis.

Urine organic acids profiling by gas chromatography-mass spectrometry (GC-MS) is routinely performed in hospital biochemical genetics laboratories for the investigation of inborn errors of metabolism. In particular, accurate identification of urinary levels of 3-hydroxyglutaric acid (3-OHGA) is important for diagnosing glutaric aciduria type 1 (GA1), but can be challenging by routine GC-MS profiling analysis due to co-elution and spectral similarity with the isomer 2-hydroxyglutaric acid (2-OHGA). To improve analytical specificity, unique ions were selected and a simple second-tier reinjection method was developed to enhance the chromatographic separation of the 2- and 3-OHGA isomers and potential unknown interferences.

Lipid analysis by ion mobility spectrometry combined with mass spectrometry: A brief update with a perspective on applications in the clinical laboratory.

Ion mobility spectrometry (IMS) is an analytical technique where ions are separated in the gas phase based on their mobility through a buffer gas in the presence of an electric field. An ion passing through an IMS device has a characteristic collisional cross section (CCS) value that depends on the buffer gas used. IMS can be coupled with mass spectrometry (MS), which characterizes an ion based on a mass-to-charge ratio (/), to increase analytical specificity and provide further physicochemical information.

Analysis of 2-methylcitric acid, methylmalonic acid, and total homocysteine in dried blood spots by LC-MS/MS for application in the newborn screening laboratory: A dual derivatization approach.

Inborn errors of propionate, cobalamin and methionine metabolism are targets for Newborn Screening (NBS) in most programs world-wide, and are primarily screened by analyzing for propionyl carnitine (C3) and methionine in dried blood spot (DBS) cards using tandem mass spectrometry (MS/MS). Single-tier NBS approaches using C3 and methionine alone lack specificity, which can lead to an increased false-positive rate if conservative cut-offs are applied to minimize the risk of missing cases. Implementation of liquid chromatography tandem mass spectrometry (LC-MS/MS) second-tier testing for 2-methylcitric acid (MCA), methylmalonic acid (MMA), and homocysteine (HCY) from the same DBS card can improve disease screening performance by reducing the false-positive rate and eliminating the need for repeat specimen collection.

Interference of ketone bodies on laboratory creatinine measurement in children with DKA: a call for change in testing practices.

Background: The presence of ketone bodies (KBs) can interfere with creatinine (Cr) measurement in both enzymatic and Jaffe methods. Since a high proportion of children hospitalized for diabetic ketoacidosis (DKA) develop acute kidney injury (AKI), here we investigate whether KB interferences affect the accuracy of pediatric Cr measurement.

Methods: Residual patient plasma samples were pooled to make three Cr levels (~ 50, 100, and 250 μM).

Low LAL (Lysosomal Acid Lipase) Expression by Smooth Muscle Cells Relative to Macrophages as a Mechanism for Arterial Foam Cell Formation.

[Figure: see text].

Smooth Muscle Cells Contribute the Majority of Foam Cells in ApoE (Apolipoprotein E)-Deficient Mouse Atherosclerosis.

Objective- Smooth muscle cells (SMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute at least 50% of atheroma foam cells. In mice, SMCs contribute fewer total lesional cells. The purpose of this study was to determine the contribution of SMCs to total foam cells in apolipoprotein E-deficient (ApoE) mice, and the utility of these mice to model human SMC foam cell biology and interventions.

Pathways of smooth muscle foam cell formation in atherosclerosis.

Purpose Of Review: Smooth muscle cells (SMCs) are the major cell type in human atherosclerosis-prone arteries and take up excess lipids, thereby contributing to luminal occlusion. Here we provide a focused review on pathways by which smooth muscle cells (SMCs) can become foam cells in atherosclerosis.

Recent Findings: A synthesis of recent and older investigations provides key mechanistic insights into SMC foam cell formation.

LAL (Lysosomal Acid Lipase) Promotes Reverse Cholesterol Transport In Vitro and In Vivo.

Objective: To explore the role of LAL (lysosomal acid lipase) in macrophage cholesterol efflux and whole-body reverse cholesterol transport.

Approach And Results: Immortalized peritoneal macrophages from lal mice showed reduced expression of ABCA1 (ATP-binding cassette transporter A1) and ABCG1 (ATP-binding cassette transporter G1), reduced production of the regulatory oxysterol 27-hydroxycholesterol, and impaired suppression of cholesterol synthesis on exposure to acetylated low-density lipoprotein when compared with lal macrophages. LAL-deficient mice also showed reduced hepatic ABCG5 (ATP-binding cassette transporter G5) and ABCG8 (ATP-binding cassette transporter G8) expression compared with lal mice.

Randomized Controlled Trial for the Effect of Vitamin D Supplementation on Vascular Stiffness in CKD.

Background And Objectives: Vitamin D is implicated in vascular health in CKD. This study compared placebo, calcifediol, and calcitriol treatment with changes in vascular stiffness, BP, proteinuria, mineral metabolism parameters, C-reactive protein, and fibroblast growth factor 23 in patients with stable CKD.

Design, Setting, Participants, & Measurements: We conducted a double-blind, randomized controlled trial in out-patient CKD clinics in Vancouver, Canada, from February of 2011 to August of 2014, enrolling 119 patients with an eGFR of 15-45 ml/min per 1.

Lamivudine, Entecavir, or Tenofovir Treatment of Hepatitis B Infection: Effects on Calcium, Phosphate, FGF23 and Indicators of Bone Metabolism.

Background: Patients with chronic hepatitis B virus (HBV) are often treated with nucleoside/nucleotide antiviral agents and metabolic bone toxicity is a possible concern.

Objective: To determine the relationships between fibroblast growth factor 23 (FGF23), a phosphaturic hormone, bone mineral density (BMD), and bone biochemical abnormalities in these patients.

Material And Methods: This is a cross-sectional observational study comparing HBV-infected subjects treated for at least one year with tenofovir (TDF), lamuvidine (LVD), entacavir (ETV), or not treated (CON).

So Much Cholesterol: the unrecognized importance of smooth muscle cells in atherosclerotic foam cell formation.

Purpose Of Review: Smooth muscle cells (SMCs) form the thickened intimal layer in atherosclerosis-prone arteries in early life, and provide the initial site for retention and uptake of atherogenic lipoproteins. Here we review current knowledge regarding the importance of SMCs in the deposition of cholesterol in atherosclerotic plaque.

Recent Findings: SMCs were found to comprise at least 50% of total foam cells in human coronary artery atherosclerosis, and exhibit a selective loss of expression of the cholesterol efflux promoter ATP-binding cassette transporter A1.

Lysosomal acid lipase: at the crossroads of normal and atherogenic cholesterol metabolism.

Unregulated cellular uptake of apolipoprotein B-containing lipoproteins in the arterial intima leads to the formation of foam cells in atherosclerosis. Lysosomal acid lipase (LAL) plays a crucial role in both lipoprotein lipid catabolism and excess lipid accumulation as it is the primary enzyme that hydrolyzes cholesteryl esters derived from both low density lipoprotein (LDL) and modified forms of LDL. Evidence suggests that as atherosclerosis progresses, accumulation of excess free cholesterol in lysosomes leads to impairment of LAL activity, resulting in accumulation of cholesteryl esters in the lysosome as well as the cytosol in foam cells.

Determination of serum aldosterone by liquid chromatography and tandem mass spectrometry: a liquid-liquid extraction method for the ABSCIEX API-5000 mass spectrometry system.

Aims: Accurate serum aldosterone determination is critical to the screening and diagnosis of primary aldosteronism, the localisation of aldosterone producing tumours, and the investigation of other disorders of the renin-angiotensin system. Mass spectrometry offers a means to overcome problems with method-dependent bias between competitive immunoassays for aldosterone. The authors have developed a simple, sensitive and precise liquid-liquid extraction aldosterone method for the ABSCIEX API-5000 liquid chromatography and tandem mass spectrometry (LC-MS/MS) system.

Serum-protein interactions with anticancer Ru(III) complexes KP1019 and KP418 characterized by EPR.

The compounds imidazolium [trans-[RuCl(4)(1H-imidazole)(2)] (KP418) and indazolium [trans-RuCl(4)(1H-indazole)(2)] (KP1019) both show significant anticancer activity, with the latter recently having completed phase I clinical trials. An important component of this success has been associated with targeted delivery of the complexes to cancer cells by serum proteins. In this study, electron paramagnetic resonance (EPR) measurements, combined with incubation under physiological conditions, and separation of protein-bound fractions, have been used to characterize the interactions of these complexes with human serum albumin (hsA), human serum transferrin (hsTf) apoprotein, and whole human serum.