Simultaneous Analysis of 272 Pesticides in Agricultural Products by the QuEChERS Method and Gas Chromatography with Tandem Mass Spectrometry.

The aim of this study is to develop a rapid and accurate method for simultaneous analysis of multi-residue pesticides and conduct pesticide monitoring in agricultural products produced by the production and distribution stage in Korea. The representative agricultural products were selected as brown rice, soybean, potato, mandarin, and green pepper and developed using gas chromatography with tandem mass (GC-MS/MS) for the analysis of 272 pesticide residues. The experimental samples were extracted by the QuEChERS-EN method and then cleaned up by using d-SPE, including MgSO4 and primary secondary amine (PSA) sorbents. The established method was validated in accordance with Codex CAC-GL/40, and the limit of quantitation (LOQ) was determined to be 0.01 mg/kg. A total of 243 pesticides satisfied the guidelines in five samples at three levels with values of 60 to 120% (recovery) and ≤45% (coefficient of variation, CV). The remaining 29 pesticides did not satisfy the guidelines, and these pesticides are expected to be used as a screening method for the routine inspection of agricultural products. As a result of analyzing 223 agricultural products in South Korea by applying the simultaneous analysis method, none of the detected levels in the samples exceeded the standard values based on maximum residue limits (MRLs). The developed method in this study will be used to inspect residual pesticides in agricultural products, and it is anticipated to contribute to the distribution of safe agricultural products to consumers.

Examination of categorical approach to symptom assessment: cross-validation of foulds' Delusions-Symptoms-States Inventory with Korean non-patient and patient groups.

BACKGROUND: Foulds' Delusions-Symptoms-State Inventory (DSSI) has been purported to be a reliable, systematic categorical measure to assess the patients with schizophrenia according to the degree of illness. However, further cross-validations using other clinical measures and diverse samples from other cultures have not been advanced recently. We aimed to examine the validity of the DSSI hierarchical class model using both Korean non-patient and patient (schizophrenia and depression) groups. METHOD: The hypothesis of inclusive, non-reflexive relationships among the DSSI classes was tested. The power of DSSI to detect presence of symptoms was assessed via cross-validation with other clinical measures, and the differences between the clinical features among the DSSI classes were examined using the Minnesota Multiphasic Personality Inventory (MMPI). RESULTS: The high rate of model conformity (91.1%) across the samples and cross-validation with other criterion measures provided further support for the validity of DSSI. CONCLUSIONS: DSSI is a reliable self-report measure that can be applied to both patient and non-patients to assess the presence and severity of psychiatric illness. Future studies that include more diverse clinical groups are necessary to lend further support for its utility in clinical practice.

Determination of Modified QuEChERS Method for Chlorothalonil Analysis in Agricultural Products Using Gas Chromatography-Mass Spectrometry (GC-MS/MS).

Chlorothalonil is an organochlorine fungicide that blocks the respiratory process of cells and persists in agricultural products because it is used extensively to prevent fungal diseases. An analytical method of chlorothalonil using the modified QuEChERS method and gas chromatography- mass spectrometry (GC-MS/MS) was developed to analyze the residue in agricultural commodities distributed in Republic of Korea. Acetonitrile, including acetic acid and formic acid, was used to compare the extraction efficiency. The extraction and purification processes were established by comparing three versions of the QuEChERS method and various dispersive solid-phase extraction (d-SPE) combinations. Ultimately, 1% formic acid in acetonitrile with QuEChERS original salts and d-SPE (PSA, C18) were selected for the extraction and clean-up procedures for method validation and establishment. Five agricultural commodities, viz., brown rice, mandarin, soybean, pepper, and potato, were examined to validate the established method, which displayed excellent linearity, with a coefficient of determination of R2 = 0.9939-0.997 in the calibration curve range of 0.002-0.1 mg/kg. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.003 mg/kg and 0.01, respectively, for the method. The LOQ value satisfied the suitable level for the Positive List System (PLS). The mean recovery of chlorothalonil was 79.3-104.1%, and the coefficient of variation was <17.9% for intra- and inter-day precision at 0.01, 0.1, and 0.5 mg/kg. The matrix effects in the five commodities were confirmed by the ion suppression effects, except for brown rice, in which a medium enhancement effect was observed at 21.4%. Chlorothalonil was detected in eight apples, one watermelon, and one cucumber. Ultimately, chlorothalonil was detected in ten agricultural products. Thus, this analytical method could be used for the routine detection of chlorothalonil in agricultural products, and the data may be used to inform and improve current food policies.

Exploration of the associations between neurocognitive function and neuroleptics side effects.

The etiology of side effects of antipsychotic medications can be conceptualized as involving both specific pharmacological actions of a drug and any mental and physical states attributed by the patient. Both factors are likely to be linked with neurocognitive functioning which may largely affect the subjective experience of side effects in patients with schizophrenia. In this study, we examined whether baseline neurocognitive functions, such as IQ, attention, executive functioning, and short-term memory, are associated with baseline and 6-month follow-up measures of self-reported Liverpool University Neuroleptics Side Effects Scale (LUNSERS) and clinician-rated Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). At the baseline, anxiety and depression were significantly associated with LUNSERS red herring (RH) and total side effects (SE) but not with DIEPSS. There was no association between LUNSERS and DIEPSS. Controlling for anxiety and depression, IQ was significantly correlated with DIEPSS, while choice reaction time (CRT) and stop signal task (SST) direction errors correlated with RH, and intra-extradimensional set-shifting (IED) total errors and pre-extradimensional set-shifting (pre-EDs) errors correlated with SE. The baseline SST direction errors further correlated significantly with RH and SE and DIEPSS total score of 6-month follow-up, and CRT mean and SD correct latency also correlated with DIEPSS. The correlations between the 6-month changes (Δ) in the same side effects measures and baseline neurocognitive measures were also significant, except that between RH and SST direction errors. Such evidences supported association between both self-rated and clinician-rated side effects and selective impairments in attention and executive functioning.

Impairments in executive functioning in patients with remitted and non-remitted schizophrenia.

OBJECTIVE: Although deficits in executive functioning are prominent in schizophrenia, some patients in remission have shown significantly higher levels of neurocognitive functioning than patients not in remission. However, no consensus on the relationship between neurocognitive functioning and the severity of symptoms has been reached. Additionally, previous studies have mainly examined the primary symptom domains of schizophrenia without considering the influence of anxiety symptoms, which are likely to influence neuropsychological performance. The aim of the present study was to compare the executive functioning of normal controls and with that of patients with schizophrenia in acute and remitted states. We further examined associations between impaired executive functioning in patients and anxiety levels. METHODS: Using a battery of tests assessing executive functioning including subtests of the Cambridge Neuropsychological Automated Test Battery (CANTAB) and the short form of the Korean Wechsler Adult Intelligence Scale (K-WAIS), we assessed 54 patients with schizophrenia and 33 normal controls. RESULTS: Our results showed that patients with non-remitted schizophrenia obtained significantly lower estimated IQ scores than did normal controls. They also exhibited longer reaction times on the Choice Reaction Time (CRT) test and the Stop Signal Test (SST) subtests of CANTAB and a greater number of total errors and errors that occurred before the extradimensional stage (i.e., pre-ED errors) on the Intradimensional/Extradimensional Shift (IED) subtest of CANTAB. Furthermore, those with schizophrenia in acute states showed significantly slower stop signal reaction times (SSRT) on the SST than did those with remitted schizophrenia and healthy controls. Finally, differences in the pre-ED errors and total adjusted errors on the IED became insignificant when scores on the Beck Anxiety Inventory (BAI) were entered as the covariate, whereas other significant differences remained when these scores were entered. CONCLUSION: Differences in executive functioning exist between patients with schizophrenia and healthy controls; these differences can be largely attributed to the relatively poor performance of patients in an active state.