27 research outputs found
High throughput on-line solid phase extraction/tandem mass spectrometric determination of paclitaxel in human serum
Quantification of perifosine, an alkylphosphocholine anti-tumour agent, in plasma by pneumatically assisted electrospray tandem mass spectrometry coupled with high-performance liquid chromatography
An HPLC assay with tandem mass spectrometric detection in the positive-ion Turbo-Ion-Spray((TM)) (TISP) mode for the fast and sensitive determination of perifosine ((I), D-21266) in human plasma was developed, utilising the structural analogue, miltefosine ((II), D-18506), as internal standard. Automated solid-phase extraction of diluted plasma samples, based on 250-μl plasma aliquots, at pH 6.5, allowed a reliable quantification of perifosine down to 4 ng/ml. Injection of 200 μl of plasma extracts onto a 100x3 mm normal-phase analytical column at a flow-rate of 0.5 ml/min provided retention-times of 2.4 and 2.1 min for perifosine (I) and the internal standard (II), respectively. The standard curves were linear from 4 to 2000 ng/ml using weighted linear regression analysis (1/Y2). The inter-assay and intra-assay accuracies for the calibration standards were within +0.9% and -0.2%, exhibiting precisions (C.V.) of ±6.5 and ±7.3%, respectively. Up to 100 unknowns may be analysed each 24 h per analyst. Copyright (C) 1999 Elsevier Science B.V
Amyloid beta protein precursor gene and hereditary cerebral-hemorrhage with amyloidosis (dutch)
Detection of zilpaterol (Zilmax®) in calf urine and faeces with liquid chromatography-tandem mass spectrometry
Zilpaterol is a new powerful beta-agonist, which is officially registered for fattening purposes in cattle in Mexico and South Africa. Its chemical structure is different from the well-known beta-agonists. Therefore, the routinely used screening methods are not likely to be suited for the analysis of zilpaterol. Also gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry (LC-MS) methods need to be adapted to enable detection of zilpaterol. In this study, a LC-MS3 confirmatory method was developed for the simultaneous detection of zilpaterol and di-aromatic beta-agonists in urine samples. A LC-MS2 method was optimised for the detection of zilpaterol in faeces. To study the excretion profile in urine and faeces, a male veal calf was orally treated with daily doses of Zilmax ® during 2 weeks. Zilpaterol was mainly excreted via urine. © 2004 Elsevier B.V. All rights reserved
Detection of zilpaterol (Zilmaxo((R))) in calf urine and faeces with liquid chromatography-tandem mass spectrometry
Ventral Capsule/Ventral Striatum Stimulation in Obsessive-Compulsive Disorder: Toward a Unified Connectomic Target for Deep Brain Stimulation?
Introduction Obsessive-compulsive disorder (OCD) is among the most disabling chronic psychiatric disorders and has a significant negative impact on multiple domains of quality of life. Deep brain stimulation (DBS) is a treatment option for severe therapy-resistant OCD. Objective To provide a detailed clinical description and treatment outcome analysis in a cohort of eight refractory OCD patients receiving ventral capsule/ventral striatum (VC/VS) stimulation with the intention to validate discriminating fiber bundles previously associated with clinical response. Materials and Methods The primary outcome measure (the Yale-Brown Obsessive Compulsive Scale [Y-BOCS]) and secondary outcomes depressive symptoms, anxiety, and quality of life were retrospectively analyzed. DBS leads were warped into standard stereotactic space. A normative connectome was used to identify the neural network associated with clinical outcome. Results With a median stimulation duration of 26 months, patients exhibited a mean Y-BOCS reduction of 10.5 resulting in a response rate of 63%. Modulation of a fiber bundle traversing the anterior limb of the internal capsule (ALIC) was associated with Y-BOCS reduction. This fiber bundle connected the frontal regions to the subthalamic nucleus (STN) and was functionally identified as the hyperdirect pathway of the basal ganglia circuitry. Conclusion Our findings show that in VC/VS stimulation, the neural network associated with clinical outcome shows overlap with that of previously described for other targets namely the anterior limb of the internal capsula, the nucleus accumbens, or the STN, which supports the evolvement from the concept of an optimal gray matter target to conceiving the target as part of a symptom modulating network