N-Alkyl-2-pyrrolidones (N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone), vapour [Air Monitoring Methods, 2014a]

This analytical method is a validated measurement procedure for the determination of gaseous N‐methyl‐2‐pyrrolidone (NMP) and N‐ethyl‐2‐pyrrolidone (NEP) and for monitoring their Occupational Exposure Limits (OELs) or MAK values at workplaces. Both personal and stationary sampling can be performed for assessment of workplaces. Sampling is performed by drawing air through an ADS‐type silica gel tube using a suitable flow‐regulated pump with a volumetric flow rate of 20 L/h. Gaseous NMP and/or NEP are adsorbed onto the silica gel. For sample preparation the collected NMP and/or NEP are desorbed from the silica gel with a potassium hydroxide solution in methanol. The sample solutions are analysed by gas chromatography using a nitrogen‐selective detector (NPD) with dibutylamine as internal standard. The quantitative determination is based on calibration functions obtained by means of multiple‐point calibrations. The limit of quantification (LOQ) for both, NMP and NEP is 1.6 µg/mL (absolute 1.6 ng), which corresponds to a relative LOQ of 0.1 mg/m3 based on an air sample volume of 40 L

Association between schizophrenia and common variation in neurocan (NCAN), a genetic risk factor for bipolar disorder

A recent study found genome-wide significant association between common variation in the gene neurocan (NCAN, rs1064395) and bipolar disorder (BD). In view of accumulating evidence that BD and schizophrenia partly share genetic risk factors, we tested this single-nucleotide polymorphism for association with schizophrenia in three independent patient-control samples of European ancestry, totaling 5061 patients and 9655 controls. The rs1064395 A-allele, which confers risk for BD, was significantly over-represented in schizophrenia patients compared to controls (p=2.28×10(-3); odds ratio=1.11). Follow-up in non-overlapping samples from the Schizophrenia Psychiatric GWAS Consortium (5537 patients, 8043 controls) provided further support for our finding (p=0.0239, odds ratio=1.07). Our data suggest that genetic variation in NCAN is a common risk factor for BD and schizophrenia