DETERMINATION OF PESTICIDE RESIDUES IN KHAT LEAVES BY SOLID-PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

The purpose of this investigation is to develop a simple method for the assessment of pesticides in Khat leaves, Catha edulis FORSK. (Celastraceae) shrub, chewed by about 60 % of the Yemeni people, producing amphetamine-like psychostimulation. The first procedures involve solid-phase extraction using Adsorbex® RP-C18 and Bakerbond® RP-C18 disposable cartridges with 40 % acetonitrile for elution. Isocratic and gradient analysis was carried out by means of high-performance liquid chromatography using different stationary phases to analyse methidathion, peconazole and dimethoate. An UltrasphereODS RP-18-column with UV-detection at 210 nm and 80/20 % (v/v) acetonitrile/water as mobile phase (isocratic) was used to determine the content of methidathion, peconazole and dimethoate (detection limit 20-25 ng). The method was validated with fortified samples at pesticide concentration of 0.1 mg/ml. Average recoveries ranging from 97.9 and 101.6% with a relative standard deviation (RSD) of 1.7-3.8 %. Each recovery analysis was repeated four times. Limits of detection ranged from the analytical procedures were applied to 5 samples of khat and no detectable amounts of pesticides were found in any sample under the conditions described

Research Paper - DETERMINATION OF PESTICIDE RESIDUES IN KHAT LEAVES BY SOLID-PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

The purpose of this investigation is to develop a simple method for the assessment of pesticides in Khat leaves, Catha edulis Forsk. (Celastraceae) shrub, chewed by about 60 % of the Yemeni people, producing amphetamine-like psychostimulation. The first procedures involve solid-phase extraction using Adsorbex® RP-C18 and Bakerbond® RP-C18 disposable cartridges with 40 % acetonitrile for elution. Isocratic and gradient analysis was carried out by means of high-performance liquid chromatography using different stationary phases to analyse methidathion, peconazole and dimethoate. An Ultrasphere®ODS RP-18-column with UV-detection at 210 nm and 80/20 % (v/v) acetonitrile/water as mobile phase (isocratic) was used to determine the content of methidathion, peconazole and dimethoate (detection limit 20-25 ng). The method was validated with fortified samples at pesticide concentration of 0.1 mg/ml. Average recoveries ranging from 97.9 and 101.6% with a relative standard deviation (RSD) of 1.7-3.8 %. Each recovery analysis was repeated four times. Limits of detection ranged from the analytical procedures were applied to 5 samples of khat and no detectable amounts of pesticides were found in any sample under the conditions described

The phenotype of recurrent 10q22q23 deletions and duplications

The genomic architecture of the 10q22q23 region is characterised by two low-copy repeats (LCRs3 and 4), and deletions in this region appear to be rare. We report the clinical and molecular characterisation of eight novel deletions and six duplications within the 10q22.3q23.3 region. Five deletions and three duplications occur between LCRs3 and 4, whereas three deletions and three duplications have unique breakpoints. Most of the individuals with the LCR3–4 deletion had developmental delay, mainly affecting speech. In addition, macrocephaly, mild facial dysmorphisms, cerebellar anomalies, cardiac defects and congenital breast aplasia were observed. For congenital breast aplasia, the NRG3 gene, known to be involved in early mammary gland development in mice, is a putative candidate gene. For cardiac defects, BMPR1A and GRID1 are putative candidate genes because of their association with cardiac structure and function. Duplications between LCRs3 and 4 are associated with variable phenotypic penetrance. Probands had speech and/or motor delays and dysmorphisms including a broad forehead, deep-set eyes, upslanting palpebral fissures, a smooth philtrum and a thin upper lip. In conclusion, duplications between LCRs3 and 4 on 10q22.3q23.2 may lead to a distinct facial appearance and delays in speech and motor development. However, the phenotypic spectrum is broad, and duplications have also been found in healthy family members of a proband. Reciprocal deletions lead to speech and language delay, mild facial dysmorphisms and, in some individuals, to cerebellar, breast developmental and cardiac defects