Analysis of Free Oligosaccharides in Urine by High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

Oligosaccharidoses are a group of lysosomal storage disorders characterized by abnormal storage and excretion of incompletely processed glycan structures. As with other inherited metabolic disorders, early diagnosis and initiation of treatment are essential for optimizing outcomes. Biochemical investigation of suspected oligosaccharidoses has traditionally included thin layer chromatography to detect the presence of disease-specific free oligosaccharides in urine; however, this qualitative method has long been known to have limited sensitivity and specificity.

Analytical Methods for Quantitative Plasma Carnitine Determination.

Carnitine is an essential molecule for mitochondrial beta-oxidation of long-chain fatty acids and other cellular functions. Several rare, inherited disorders of carnitine metabolism occur in humans, and secondary carnitine deficiency is an important feature in a variety of clinical settings. Many of these conditions can be detected via quantitative analysis of free and esterified carnitine in plasma or urine, which thus offers an effective means for assessing the transport and initial processing of fatty acids.

Laboratory analysis of amino acids, 2018 revision: a technical standard of the American College of Medical Genetics and Genomics (ACMG).

Amino acid abnormalities are observed in a broad spectrum of inherited metabolic diseases, such as disorders of amino acid metabolism and transport, organic acidemias, and ureagenesis defects. Comprehensive analysis of physiologic amino acids in blood, urine, and cerebrospinal fluid is typically performed in the following clinical settings: evaluation of symptomatic patients in whom a diagnosis is not known; evaluation of previously diagnosed patients to monitor treatment efficacy; evaluation of asymptomatic or presymptomatic (at-risk) relatives of known patients; follow-up testing for an abnormal newborn screen; and assessment of dietary protein adequacy or renal function in general patient populations. Currently, the most common analytical method to quantify amino acids is based on ion exchange chromatography using post-column derivatization with ninhydrin and spectrophotometric detection.

Urine oligosaccharide screening by MALDI-TOF for the identification of NGLY1 deficiency.

N-glycanase deficiency (NGLY1 deficiency, NGLY1-CDDG), the first autosomal recessive congenital disorder of N-linked deglycosylation (CDDG), is caused by pathogenic variants in NGLY1. The majority of affected individuals have been identified using exome or genome sequencing. To date, no reliable, clinically available biomarkers have been identified.

Methods for Quantitative Creatinine Determination.

Reliable measurement of creatinine is necessary to assess kidney function, and also to quantitate drug levels and diagnostic compounds in urine samples. The most commonly used methods are based on the Jaffe principal of alkaline creatinine-picric acid complex color formation. However, other compounds commonly found in serum and urine may interfere with Jaffe creatinine measurements.

Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study.

Background: Outbreaks of unexplained illness frequently remain under-investigated. In India, outbreaks of an acute neurological illness with high mortality among children occur annually in Muzaffarpur, the country's largest litchi cultivation region. In 2014, we aimed to investigate the cause and risk factors for this illness.

Laboratory diagnosis of creatine deficiency syndromes: a technical standard and guideline of the American College of Medical Genetics and Genomics.

Disclaimer: These ACMG Standards and Guidelines are intended as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these standards and guidelines is voluntary and does not necessarily assure a successful medical outcome. These Standards and Guidelines should not be considered inclusive of all proper procedures and tests or exclusive of others that are reasonably directed to obtaining the same results.

Quantitative Analysis of Total Plasma Homocysteine by LC-MS/MS.

Homocysteine is a nonessential, sulfur-containing amino acid involved in one-carbon (folate) metabolism. A number of inherited and acquired conditions cause increased accumulation of this metabolite in blood (homocysteinemia) and other biofluids. Homocysteinemia is a risk factor for cardiovascular disease, including recurrent thrombosis.

An Overview of Biochemical Genetics.

Biochemical genetics focuses on the pathophysiology, diagnosis, and treatment of inherited metabolic disorders. While individually rare, the combined incidence of these diseases makes them a significant source of morbidity and mortality, particularly among infants and young children, and new conditions continue to be identified. Inherited metabolic disorders may present as an acute, life-threatening illness or with more chronic, progressive symptoms.

Carnitine Palmitoyltransferase 1b Deficient Mice Develop Severe Insulin Resistance After Prolonged High Fat Diet Feeding.

Background: Carnitine palmitoyltransferase 1 (CPT1) is the rate-limiting enzyme governing the entry of long-chain acyl-CoAs into mitochondria. Treatments with CPT1 inhibitors protect against insulin resistance in short-term preclinical animal studies. We recently reported that mice with muscle isoform CPT1b deficiency demonstrated improved insulin sensitivity when fed a High Fat-Diet (HFD) for up to 5 months.

Olfactory dysfunction in Parkinson's disease: Positive effect of cigarette smoking.

Background: There is compelling evidence from over 60 epidemiological studies that smoking significantly reduces the risk of Parkinson's disease (PD). In general, those who currently smoke cigarettes, as well as those with a past history of such smoking, have a reduced risk of PD compared to those who have never smoked. Recently it has been suggested that a cardinal nonmotor sensory symptom of PD, olfactory dysfunction, may be less severe in PD patients who smoke than in PD patients who do not, in contrast to the negative effect of smoking on olfaction described in the general population.

Carnitine Palmitoyltransferase 1b Deficiency Protects Mice from Diet-Induced Insulin Resistance.

Background: Carnitine Palmitoyl Transferase 1 (CPT1) is the rate-limiting enzyme governing long-chain fatty acid entry into mitochondria. CPT1 inhibitors have been developed and exhibited beneficial effects against type II diabetes in short-term preclinical animal studies. However, the long-term effects of treatment remain unclear and potential non-specific effects of these CPT1 inhibitors hamper in-depth understanding of the potential molecular mechanisms involved.

Comparison of methods, storage conditions, and time to analysis of serum and urine creatinine measured from microsamples by liquid chromatography mass spectrometery (LC/MS) vs. Jaffe.

Background: Measurement of serum creatinine (SCr) and urine creatinine (UCr) is regularly used in clinical and research settings. For small animal experiments and for studies in which sample collection is spare (i.e.

Simultaneous quantification of F2-isoprostanes and prostaglandins in human urine by liquid chromatography tandem-mass spectrometry.

A specific and sensitive LC-MS/MS method for analysis of F(2)-isoprostanes (F(2)-IsoPs) and prostaglandins (PGs) in urine was developed and validated to examine the levels of F(2)-IsoPs and prostaglandin F(2α) (PGF(2α)), in human urine in patients undergoing cardiac surgery. The rapid extraction for F(2)-IsoPs and PGs from urine was achieved using a polymeric weak anion solid phase extraction cartridge. The base-line separation of 8-iso-PGF(2α), 8-iso-15(R)-PGF(2α), PGF(2α), and 15(R)-PGF(2α) was carried out on a Hydro-RP column (250mm×2.

An overview of biochemical genetics.

Biochemical genetics focuses on the pathophysiology, diagnosis, and treatment of inherited metabolic disorders. While individually rare, the combined incidence of these diseases is likely greater than 1:3000 live births. These conditions may present in the neonatal period as an acute, life-threatening illness, or may manifest later in childhood with symptoms of progressive neurodegeneration, skeletal abnormalities, and/or dysmorphia.

Tackling sundowning in a patient with Alzheimer's disease.

The early evening exacerbation of behavioral symptoms in sundowning has been recognized by medical professionals as a challenge. The circadian, hormonal, physiological, and environmental correlations with sundowning behaviors are described.

Homozygous carnitine palmitoyltransferase 1b (muscle isoform) deficiency is lethal in the mouse.

Carnitine palmitoyltransferase-1 (CPT-1) catalyzes the rate-limiting step of mitochondrial beta-oxidation of long chain fatty acids (LCFA), the most abundant fatty acids in mammalian membranes and in energy metabolism. Human deficiency of the muscle isoform CPT-1b is poorly understood. In the current study, embryos with a homozygous knockout of Cpt-1b were lost before embryonic day 9.

Assays used in the analysis of Arl2 and its binding partners.

Arl2 is a approximately 20 kDa GTPase in the ADP-ribosylation factor (Arf) family within the Ras superfamily with roles in microtubule dynamics that impact the cytoskeleton, cell division, and cytokinesis. Arl2 has been implicated as a regulator of the pathway responsible for formation of properly folded tubulin heterodimers and in adenine nucleotide transport in mitochondria. The identification and characterization of Arl2 binding partners and regulators of Arl2 activities are critical steps in the further dissection of these and likely other Arl2-dependent functions.

The adenine nucleotide translocase type 1 (ANT1): a new factor in mitochondrial disease.

Mitochondrial disorders of oxidative phosphorylation (OXPHOS) comprise a growing list of potentially lethal diseases caused by mutations in either mitochondrial (mtDNA) or nuclear DNA (nDNA). Two such conditions, autosomal dominant progressive external ophthalmoplegia (adPEO) and Senger's Syndrome, are associated with dysfunction of the heart and muscle-specific isoform of the adenine nucleotide translocase (ANT1), a nDNA gene product that facilitates transport of ATP and ADP across the inner mitochondrial membrane. AdPEO is a mtDNA deletion disorder broadly characterized by pathology involving the eyes, skeletal muscle, and central nervous system.

Medium-chain acyl-CoA dehydrogenase deficiency in gene-targeted mice.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common inherited disorder of mitochondrial fatty acid beta-oxidation in humans. To better understand the pathogenesis of this disease, we developed a mouse model for MCAD deficiency (MCAD-/-) by gene targeting in embryonic stem (ES) cells. The MCAD-/- mice developed an organic aciduria and fatty liver, and showed profound cold intolerance at 4 degrees C with prior fasting.

Cytosolic Arl2 is complexed with cofactor D and protein phosphatase 2A.

Arl2 is a member of the ADP-ribosylation factor family of 20-kDa GTPases that is highly conserved in eukaryotes. Recent results revealed that a portion of cellular Arl2 and its binding partner, BART, localize to mitochondria. Because approximately 90% of cellular Arl2 is cytosolic, we investigated properties of the soluble protein and found that it is stably bound in a complex that migrates in gel filtration medium with a predicted molecular mass of approximately 300 kDa.