Response surface optimization for determination of pesticide residues in grapes using MSPD and GC-MS: assessment of global uncertainty.

In this work, a simple and low-cost method based on matrix solid-phase dispersion (MSPD) and gas chromatography to determine eight multi-class pesticides such as vinclozolin, dichlofluanid, penconazol, captan, quinoxyfen, fluquinconazol, boscalid, and pyraclostrobin in grapes is described. Fungicide residues were identified and quantified using gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS, SIM). The experimental variables that affect the MSPD method, such as the amount of solid phase, solvent nature and elution volume were optimized using an experimental design. The best results were obtained using 0.5 g of grapes, 1.0 g of silica as clean-up sorbent, 1.50 g of C(18) as bonded phase and 10 mL of dichloromethane/ethyl acetate (1:1, v/v) as eluting solvent. Significant matrix effects observed for most of the pesticides tested were eliminated using matrix-matched standards. The pesticide recoveries in grapes samples were better than 80% except for captan. Intra-laboratory precision in terms of Horwitz ratio of the pesticides evaluated was below 0.5, suggesting ruggedness of the method. The quantification limits of the pesticides were in the range of 3.4-8.7 microg kg(-1), which were lower than the maximum residue limits (MRLs) of the pesticides in grapes samples established by the European legislation. Decision limits (CCalpha) and detection capability (CCbeta) have been calculated. The expanded uncertainties at two levels of concentration were <20% for all analytes.

EUS FNA in intraductal papillary mucinous tumors of the pancreas.

BACKGROUND/AIMS: There is little information concerning the potential role of fine-needle aspiration guided by endoscopic ultrasonography in the pathologic diagnosis of intraductal papillary mucinous tumors of the pancreas. METHODOLOGY: Patients with an intraductal papillary mucinous tumor of the pancreas suggested by endoscopic ultrasonography underwent fine-needle aspiration guided by endoscopic ultrasonography in order to investigate the presence of mucin and/or cytologic changes consistent with this diagnosis. A group of 111 patients with other pancreatic lesions explored during the same period of time was used as a control group. RESULTS: Fine-needle aspiration guided by endoscopic ultrasonography was safely performed in 19 patients and supported the diagnosis in 17 of them. Nine out of the 17 patients with suspicion of intraductal papillary mucinous tumors of the pancreas went to surgery and this diagnosis was confirmed in the resected specimen in all of them. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of EUS FNA in the diagnosis of IPMT were 82%, 100%, 100%, 92% and 94% respectively. CONCLUSIONS: Fine-needle aspiration guided by endoscopic ultrasonography is a good technique to support the diagnosis of intraductal papillary mucinous tumors of the pancreas and should be considered in this group of patients if pathologic confirmation is judged to be necessary.

Endoscopic findings in a biennial follow-up program in patients with pernicious anemia.

BACKGROUND/AIMS: It is known that patients with pernicious anemia have a higher risk of gastric neoplasms. However, the optimal endoscopic follow-up in these patients has not been properly defined. This study was aimed to assess the usefulness of an endoscopic follow-up program. METHODOLOGY: We analyzed the endoscopic and histological findings of the first endoscopy performed in a group of 128 patients with the diagnosis of pernicious anemia who were referred to the Endoscopic Unit, and we evaluated the results of the biannual follow-up endoscopies made to 68 of them. RESULTS: The initial endoscopy did not provide evidence of any lesions in 107 patients (83.5%), and polypoid lesions were found in 12 cases (9.4%). The histological results showed gastric dysplasia in 3 patients (2.3%) and carcinoid tumor in 2 cases (1.6%). No cases of gastric carcinoma were found. During the endoscopic follow-up of 68 patients, in 52 of them (76.8%) there were no endoscopic findings, and raised lesions were detected in 8 patients (11.8%). Three cases of gastric dysplasia were found. No cases of gastric carcinoma or carcinoid were detected during the follow-up. CONCLUSIONS: We suggest that a biannual endoscopic follow-up in not useful for the early detection of gastric neoplasms in patients with pernicious anemia.

Comparison of four extraction methods for the determination of fungicide residues in grapes through gas chromatography-mass spectrometry.

Four different methods for simultaneous extraction of vinclozolin, dichlofluanid, penconazole, captan, quinoxyfen, fluquinconazol, boscalid and pyraclostrobin from grapes were optimized and further tested. Microwave assisted extraction (MAE), matrix solid-phase dispersion (MSPD), solid-liquid extraction (SLE) and QuEChERS were compared in terms of their limits of detection and quantification and recoveries. For MAE, MSPD and ethyl acetate extraction, the optimal conditions were optimized by using experimental designs. The analysis was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode (GC-MS, SIM). The proposed methods showed good sensitivity, limits of quantification were lower than MRLs and precision (expressed as relative standard deviation) ranged from 2.9 to 11.1%. The recoveries obtained from MAE, MSPD, SLE and QuEChERS were in the range 78-100%, 66-102%, 58-88% and 68-96%, respectively. In addition, the four methods were compared in two ways: by means of calibration curves obtained with 10 fortified samples in the studied range of concentrations and by the application of statistical tests such as Levene's test (to study variance homogeneity), ANOVA and Tukey's test (in case of Levene's test was satisfactory) for the assessment of the information obtained in the analysis of real samples. Both ways of comparison led to the same results: no differences between the four methods for the extraction of vinclozolin, dichofluanid, quinoxyfen, fluquinconazol and pyraclostrobin were found. However, there were differences for the analysis of captan, boscalid and penconazole.

Fate and distribution of pyrimethanil, metalaxyl, dichlofluanid and penconazol fungicides from treated grapes intended for winemaking.

Tempranillo grapes were immersed in solutions of pyrimethanil, metalaxyl, dichlofluanid and penconazol fungicides at different concentrations for several different times. Determinations of the fungicide residues was carried out by GC-NPD, with an additional confirmation by GC-MS. The percentage absorption was determined as well as the distribution between surface, skin and pulp of the grapes. The percentage absorption ranged from 7.2 to 85.5%. These values depended on the time the grapes were in contact with the fungicide solutions. Residues were mainly found in skins, with percentages in skins ranging from 66.3 to 90.3% of total residues. In pulp, these values ranged from 3.5 to 31.0%. The overall methodology was applied to the determination of pyrimethanil in Tempranillo grapes treated with the recommended doses, respecting the safety period. Pyrimethanil residues found in treated grapes were higher in the skin. In grapes collected within the safety period (21 days), the levels found for fungicide residues were below maximum residues levels.

Visceral leishmaniasis diagnosed by colonoscopy.

Zoonotic visceral leishmaniasis is common in western Mediterranean countries. A strong link between visceral leishmaniasis and human immunodeficiency virus (coinfection) has been proved, especially in Spain, which is an endemic area. This suggests that Leishmania may behave opportunistically. We report a case of colonic leishmaniasis in a 23-year-old Spanish woman infected with the human immunodeficiency virus.

Endoscopic injection therapy in bleeding Mallory-Weiss syndrome: a randomized controlled trial.

BACKGROUND: Endoscopic injection is widely used in the therapy of bleeding gastroduodenal ulcers, but its role in the management of bleeding Mallory-Weiss tears has not been properly assessed. METHODS: Sixty-three patients undergoing emergency endoscopy in whom there was a high index of suspicion that a Mallory-Weiss tear was the source of bleeding were randomly assigned to undergo endoscopic injection therapy (epinephrine and polidocanol) or no endoscopic therapy in 2 university-affiliated hospitals. Rates of recurrent bleeding, transfusion requirements, complications, mortality, and length of hospital stay were determined for both groups of patients. RESULTS: Bleeding recurred in 8 patients in the control group versus only 2 in the endoscopic treatment group (25.8% vs. 6.2%, p < 0.05). Hospital stay was longer for the control group (5.5 +/- 0.2, median 6.0, range 2.0-8.0 days vs. 3.4 +/- 0.2, median 3.0, range 2.0-6.0 days; p < 0.001). There was a trend toward a higher transfusion requirement after endoscopy in the control group versus the patients treated by injection (0.9 +/- 0.2, median 0.0, range 0.0-4.0 units vs. 0.2 +/- 0.1, median 0.0, range 0.0-2.0 units; p = 0.09). No complications or adverse events caused by endoscopic injection were noted. Two patients in the control group died of causes unrelated to bleeding. CONCLUSIONS: Endoscopic injection therapy is a useful option in the management of patients with Mallory-Weiss syndrome at high risk for recurrent bleeding.

Follow-up of a large-B-cell pancreatic lymphoma by endoscopic ultrasonography.

Although computed tomography and endoscopic ultrasound (EUS) are well-established procedures used to evaluate pancreatic masses, it is well known that imaging techniques alone cannot be used to distinguish between adenocarcinoma and tumors of less common cellular origin, such as primary pancreatic lymphoma. Clinicians must always consider this kind of malignancy in their differential diagnosis since, although rare, its treatment is nonsurgical and it has a better prognosis than adenocarcinoma. Histological examination of focal masses in the pancreas is therefore mandatory in order to establish the best therapeutic approach for every patient. Endoscopic ultrasound has developed as a very useful tool for the diagnosis of pancreatic tumors but could also be considered as a very useful method in the follow-up of these patients after treatment.

Simultaneous determination of organotin compounds by hydride generation-gas phase molecular absorption spectrometry.

This study describes the determination of ternary mixtures of dimethyltin chloride (DMT), trimethyltin chloride (TMT) and monobutyltin chloride (BT) by hydride generation-gas phase molecular absorption spectrometry and the application of different chemometric methods: principal components regression (PCR) and partial least squares (PLS). The two methods are applied to the absorption spectra of mixtures of DMT, TMT and BT. Two different experimental designs are tested for the mixtures, a triangular design and a central composite design. The models obtained from the triangular design offer the best prediction results. The effects of the number of working wavelengths and the number of factors included in the calibration model is studied and a different behaviour is seen for each compound and calibration model. The methods are applied to the analysis of artificial aqueous samples containing different concentrations of DMT, TMT and BT species. No significant differences are observed between the calibration models investigated.