Measurement of 7-dehydrocholesterol and cholesterol in hair can be used in the diagnosis of Smith-Lemli-Opitz syndrome.

7-dehydrocholesterol (7-DHC) and cholesterol (CHOL) are biomarkers of Smith-Lemli-Opitz Syndrome (SLOS), a congenital autosomal recessive disorder characterized by elevated 7-DHC level in patients. Hair samples have been shown to have great diagnostic and research value, which has long been neglected in the SLOS field. In this study, we sought to investigate the feasibility of using hair for SLOS diagnosis. In the presence of antioxidants (2,6-ditert-butyl-4-methylphenol and triphenylphosphine), hair samples were completely pulverized and extracted by micro-pulverized extraction in alkaline solution or in n-hexane. After microwave-assisted derivatization with N,O-Bis(trimethylsilyl)trifluoroacetamide, the analytes were measured by GC-MS. We found that the limits of determination for 7-DHC and CHOL were 10 ng/mg and 8 ng/mg, respectively. In addition, good linearity was obtained in the range of 50-4000 ng/mg and 30-6000 ng/mg for 7-DHC and CHOL, respectively, which fully meets the requirement for SLOS diagnosis and related research. Finally, by applying the proposed method to real hair samples collected from 14 healthy infants and two suspected SLOS patients, we confirmed the feasibility of hair analysis as a diagnostic tool for SLOS. In conclusion, we present an optimized and validated analytical method for the simultaneous determination of two SLOS biomarkers using human hair.

A reliable tool for detecting 7-dehydrocholesterol and cholesterol in human plasma and its use in diagnosis of Smith-Lemli-Opitz syndrome.

BACKGROUND: Smith-Lemli-Opitz syndrome is a birth defect caused by the deficiency of 7-dehydrocholesterol reductase in cholesterol biosynthesis pathway, which leads to accumulation of 7-dehydrocholesterol and reduction of cholesterol in body fluids. To effectively diagnose Smith-Lemli-Opitz syndrome and monitor therapy, a reliable method for simultaneous detection of 7-dehydrocholesterol and cholesterol is needed. METHODS: In the presence of antioxidants (2,6-ditert-butyl-4-methylphenol and triphenylphosphine), 50 µL of human plasma were hydrolyzed at 70℃ for 40 min with 1 M potassium hydroxide in 90% ethanol, and then 7-dehydrocholesterol and cholesterol were extracted by 600 µL of n-hexane for three times. After microwave-assisted derivatization with 70 µL of N,O-bis(trimethylsilyl)trifluoroacetamide at 460 W for 3 min, the analytes were measured by gas chromatography-mass spectrometry. RESULTS: The limits of detection were 100 ng/mL for 7-dehydrocholesterol and 300 ng/mL for cholesterol. Good linearity was obtained in the range of 1-600 µg/mL for 7-dehydrocholesterol and 10-600 µg/mL for cholesterol, which completely covered the biochemical levels of Smith-Lemli-Opitz syndrome patients that have been reported. CONCLUSION: A time-saving and accurate gas chromatography with mass spectrometry based method was developed for the determination of 7-dehydrocholesterol and cholesterol in human plasma, which also serves as a useful tool for Smith-Lemli-Opitz syndrome diagnosis, treatment, and research.

[Determination of 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline, 5-hydroxytryptamine and 5-hydroxyindole acetic acid in the neonatal rat brains using high performance iquid chromatography-electrochemical detection].

A simple method was developed for the analysis of 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline (6-OH-MTHbetaC), 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat brain by high performance liquid chromatography with electrochemical detection (HPLC-ECD). The separation of the sample was performed on a Discovery HS F5 column (250 mm x 4.6 mm, 5 microm) with a mobile phase of the buffer (40 mmol/L citric acid + 20 mmol/L Na2HPO4 + 0.3 mmol/L EDTA2Na, pH 4.0)-methanol (78:22, v/v) at a flow rate of 1.0 mL/min. The electrochemical detector was Coularray Detector-4. This method showed good linearity (r > 0.9992) for the quantification of 6-OH-MTHbetaC, 5-HT and 5-HIAA in the concentration range of 1.0-500.0 microg/L. The limits of detection were 0.56, 0.26 and 0.53 microg/L, respectively. The recoveries of 6-OH-MTHbetaC, 5-HT and 5-HIAA spiked in rat brain samples were 87.1%-98.2%, 87.0%-95.3%, 90.1%-97.7%, respectively, and the relative standard deviations of intra-day and inter-day determinations were both less than 6.1%. In comparison with the control, the analysis of alcohol-exposed neonatal rat brain samples revealed a significant difference in the level of 6-OH-MTHbetaC (P < 0.05). The method was proved to be simple, highly sensitive, and could be applied in the analysis of 6-OH-MTHbetaC, 5-HT and 5-HIAA in the rat brain.

The formation of catechol isoquinolines in PC12 cells exposed to manganese.

Chronic exposure to manganese causes parkinsonian symptoms and has been implicated as an environmental factor in the pathogenesis of Parkinson's disease (PD). Here we show that manganese inhibits the proliferation of PC12 cells and induces apoptosis through the formation of catechol isoquinolines. Manganese induces the production of 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol, Sal) and N-methyl-salsolinol (NMSal) in PC12 cells, and increases the levels of malondialdehyde (MDA) in a dose-dependent manner. The data indicates that the formation of catechol isoquinolines due to oxidative stress induced by MnCl(2) may be a mechanism by which manganese causes degeneration of dopaminergic neurons.