A hydrophobic silica dusting agent containing carbon black has been used with latent finger marks to demonstrate that the agent can act as an enhancing matrix to generate a simple method for detecting a range of drugs using surface assisted laser desorption/ionisation time-of-flight mass spectrometry (SALDI-TOF-MS) in positive ion reflectron mode. The dusting agent produces developed marks for locating/visualising the prints whilst also acting as a SALDI-TOF-MS enhancer that is equivalent to the standard matrix enhancer 2,5-dihydroxybenzoic acid. This method has been applied to the analysis of latent fingermarks for contact residues on fingers, and for detection of illicit drugs for both parent drugs and their metabolites. Analysis was performed by direct MS analysis of the pre-dusted fingermarks on the surface of a target plate and, following lifting using commercial tape, MS analysis of the lifted marks. When 19 commercial powders were used only three produced MS spectra but with intensities less than those produced with the new powder. The presence of the parent drug and its metabolites was confirmed using SALDI-TOF-MS-MS following high energy collision induced dissociation when characteristic and unique fragmentation patterns were observed in each case. The distribution of these compounds on fingermarks was subsequently demonstrated using commercially available imaging software.
Objective-To determine the feasibility of establishing a system ofscreening for neuroblastoma.Design-Prospective study of mass screening in four clearly defined geographical areas.Setting--Four health districts of the Northern region ofEngland.Subjects-20 829 babies aged 6 months, 92% of target population.Interventions-Collection of urine on filter paper for analysis of content of homovanillic and vanillylmandelic acid in relation to urinary creatinine concentrations.Main outcome measures-Derivation of reference range. Identification of babies with homovanillic or vanillylmandelic acid >3 SD above the mean (positive cases). Investigation of positive cases for evidence ofneuroblastoma.Results-The upper limit of normal (3 SD above the mean) for vanillylmandelic acid was 15 pLmol/mmol creatinine and for homovanillic acid 24 tmol/mmol creatinine. Of the 20 829 babies screened, 2537 (12-2%) required a second sample to be taken because the first sample was inadequate. Of these, 527 (2.5%) provided a liquid urine specimen and 10 (0.040/o) had positive results for neuroblastoma. Two of them had neuroblastoma (true positives) and eight did not (false positives). A further three children from the cohort were subsequently found to have neuroblastoma; they had raised homovanillic acid or vanillylmandelic acid values, or both, but screened negative at 6 months.Conclusions-Screening for neuroblastoma is possible in the health care system of the United Kingdom. Evaluation of the efficacy of screening in reducing the mortality from neuroblastoma requires a controlled trial.
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