Whole blood propionylcarnitine in newborns with orofacial cleft

Orofacial clefts are thought to be determined by the interplay of genetic and environmental factors. Experiments on animals demonstrated that vitamin B12 supplemented diets antagonize selected teratogens during palatogenesis. Increased propionylcarnitine in neonates is regarded as a marker of maternal vitamin B12 deficiency. The retrospective study was undertaken to determine whether increased propionylcarnitine in newborns is associated with orofacial clefts. Fifty-two newborns with isolated cleft lip with or without cleft palate (CLP) and 107 control newborns without congenital anomalies were investigated. Whole blood propionylcarnitine concentrations were measured using tandem mass spectrometry. The mean concentrations of propionylcarnitine in newborns with clefts and controls were 2.82±1.06µmolL(-1) and 2.68±0.94µmolL(-1), respectively. T-test for equality of means did not confirm any significant differences between both groups (P=0.381). Deficiency of vitamin B12 with metabolic disturbances seems not to be a risk factor for CLP in the investigated group of patients.

Liquid chromatography-tandem mass spectrometry applications in endocrinology

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been recognized as a primary methodology for the accurate analysis of endogenous steroid hormones in biological samples. This review focuses on the use of LC-MS/MS in clinical laboratories to assist with the diagnosis of diverse groups of endocrine and metabolic diseases. Described analytical methods use on-line and off-line sample preparation and analytical derivatization to enhance analytical sensitivity, specificity, and clinical utility. Advantages of LC-MS/MS as an analytical technique include high specificity, possibility to simultaneously measure multiple analytes, and the ability to assess the specificity of the analysis in every sample. All described analytical methods were extensively validated, utilized in routine diagnostic practice, and were applied in a number of clinical and epidemiological studies, including a study of the steroidogenesis in ovarian follicles.

Neonatal vitamin B12 deficiency secondary to maternal subclinical pernicious anemia: identification by expanded newborn screening

A neonate with elevated propionylcarnitine on the newborn screen was found to have methylmalonic acidemia due to vitamin B(12) deficiency. The mother was also vitamin B(12)-deficient. This case illustrates the utility of expanded newborn screening for detection of vitamin B(12) deficiency, allowing prompt treatment and prevention of potential sequelae.

Increased formation of short-chain organic acids after chronic ethanol administration and its interaction with the carnitine pool in rat

Organic acidurias are genetic disorders of mitochondrial metabolism that lead to the accumulation of organic acids in tissues and biological fluids. It has been demonstrated that interaction of carnitine with the cellular coenzyme A (CoA) pool, through the production of acyl-carnitines, is potentially critical for maintaining normal cellular metabolism under condition of impaired acyl-CoA use and that exposure of humans and other mammals to ethanol leads to impairment of mitochondrial function. The aim of the present study was to evaluate the role of chronic administration of ethanol on urinary excretion of short-chain organic acids and endogenous carnitines in rats. The data reported show that chronic administration of ethanol significantly increases urinary excretion of propionate, methylmalonate, as well as free acetate, butyrate, pyruvate, lactate, and beta-hydroxybutyrate. Chronic administration of propranolol abolished ethanol-dependent accumulation of propionate, suggesting involvement of beta-adrenergic mechanisms. Increased formation of propionate and methylmalonate was associated with decreased plasma carnitine levels and with increased excretion of specific acyl-carnitines, corresponding to the accumulating acyl groups. Our data indicate that chronic alcohol ingestion induces increased excretion of selected organic acids and that the endogenous carnitine pool might exert a protective role against the deleterious effects of accumulating short-chain organic acids.