VILMA LEYTON
Projetos de Pesquisa
Unidades Organizacionais
Departamento de MedicinaLegal, Ética Médica e Medicina Social e do Trabalho, Faculdade de Medicina - Docente
LIM/40 - Laboratório de Imunohematologia e Hematologia Forense, Hospital das Clínicas, Faculdade de Medicina - Líder
LIM/40 - Laboratório de Imunohematologia e Hematologia Forense, Hospital das Clínicas, Faculdade de Medicina - Líder
7 resultados
Resultados de Busca
Agora exibindo 1 - 7 de 7
- Determination of cocaine and its derivatives in hair samples by liquid phase microextraction (LPME) and gas chromatography-mass spectrometry (GC-MS)(2017) PEGO, A. M. F.; ROVERI, F. L.; KUNINARI, R. Y.; LEYTON, V.; MIZIARA, I. D.; YONAMINE, M.Hair testing is a recognized approach when it comes to accessing historical drug use. According to the World Drug Report of United Nations Office on Drugs and Crime (UNODC) 2015, Brazil is the largest cocaine (COC) market in South America. New analytical methodologies to detect crack/cocaine analytes in hair samples are highly desirable. Here, a method consisting of a liquid-phase microextraction (LPME) as a clean-up step, followed by gas chromatography-mass spectrometry (GC-MS) analysis has been proposed. The new validated method consisted of a washing step; an overnight incubation with methanol and a quick derivatization with butylchloroformate. Once derivatized, the samples were then submitted to the LPME procedure. Limits of detection (LoD) and quantitation (LoQ) obtained were of 0.1 and 0.5 ng/ mg for COC 0.4 and 0.5 ng/mg for anhydroecgonine methyl ester (AEME); 0.03 and 0.05 for cocaethylene (CE), respectively and 0.05 ng/mg for both LoD and LoQ for benzoylecgonine (BZE). All calibration curves were linear over the scope applied, from LoQ up to 20 ng/mg, with a r(2) > 0.99. Precision and accuracy assays showed acceptable % RSD values, according to international guidelines. Twelve postmortem head hair samples stemming from the Institute of Legal Medicine of Sao Paulo (IML-SP) have been analyzed, from which seven have shown to be positive for COC (0.75-> 20 ng/mg) and BZE (0.1-> 20 ng/mg). Apart from COC's main metabolite, four samples were also positive for CE (0.1-3.9 ng/mg) and three samples for AEME (0.5-4.9 ng/mg). To conclude, the LPME technique together with GC-MS analysis have shown promising results and were able to meet the demand of the laboratory of analyzing postmortem hair samples to look for all four analytes.
- Amphetamine, cocaine and cannabinoids use among truck drivers on the roads in the State of Sao Paulo, Brazil(2012) LEYTON, V.; SINAGAWA, D. M.; OLIVEIRA, K. C. B. G.; SCHMITZ, W.; ANDREUCCETTI, G.; MARTINIS, B. S. De; YONAMINE, M.; MUNOZ, D. R.Drugs are important risk factors for traffic accidents. In Brazil, truck drivers report using amphetamines to maintain their extensive work schedule and stay awake. These drugs can be obtained without prescription easily on Brazilian roads. The use of these stimulants can result in health problems and can be associated with traffic accidents. There are Brazilian studies that show that drivers use drugs. However, these studies are questionnaire-based and do not always reflect real-life situations. The purpose of this study was to demonstrate the prevalence of drug use by truck drivers on the roads of Sao Paulo State, Brazil, during 2009. Drivers of large trucks were randomly stopped by police officers on the interstate roads during morning hours. After being informed of the goals of the study, the drivers gave written informed consent before providing a urine sample. In addition, a questionnaire concerning sociodemographic characteristics and health information was administered. Urine samples were screened for amphetamines, cocaine, and cannabinoids by immunoassay and the confirmation was performed using gas chromatography-mass spectrometry (GC-MS). Of the 488 drivers stopped, 456 (93.4%) provided urine samples, and 9.3% of them (n = 42) tested positive for drugs. Amphetamines were the most commonly found (n = 26) drug, representing 61.9% of the positive samples. Ten cases tested positive for cocaine (23.8%), and five for cannabinoids (11.9%). All drivers were male with a mean age of 40 +/- 10.8 years, and 29.3% of them reported some health problem (diabetes, high blood pressure and/or stress). A high incidence of truck drivers who tested positive for drug use was found, among other reported health problems. Thus, there is an evident need to promote a healthier lifestyle among professional drivers and a need for preventive measures aimed at controlling the use of drugs by truck drivers in Brazil.
- Prevalence of drugs in oral fluid from truck drivers in Brazilian highways(2017) BOMBANA, Henrique Silva; GJERDE, Hallvard; SANTOS, Marcelo Filonzi dos; JAMT, Ragnhild Elen Gjulem; YONAMINE, Mauricio; ROHLFS, Waldo Jose Caram; MUNOZ, Daniel Romero; LEYTON, VilmaTraffic accidents are responsible for 1.25 million deaths worldwide and are the most common cause of death among those aged 15-29 years. In Brazil, traffic accidents caused more than 44,000 deaths in 2014. The use of psychoactive drugs is an important risk factor for being involved in traffic accidents. Previous studies have found that psychoactive substances are commonly used by truck drivers in Brazil to maintain their extensive work schedule and stay awake while driving during nighttime hours. The state of Sao Paulo is one of the most important states regarding goods transportation. Important highways cross through Sao Paulo to other regions from Brazil and to other countries in Latin America. This study aims to determine the prevalence of illicit drug use by truck drivers in the state of Sao Paulo through toxicological analyses of oral fluid. Truck drivers were randomly stopped by police officers on federal roads during morning hours. Oral fluid samples were collected using the Quantisal (TM) device. In addition, a questionnaire concerning sociodemographic characteristics and health information was administered. Oral fluid samples were screened for amphetamine, cocaine, and tetrahydrocannabinol (Delta 9-THC) by ELISA and the confirmation was performed using ultra performance liquid chromatography with tandem mass spectrometry detection (UPLC-MS/MS). Of the 764 drivers stopped, 762 agreed to participate. The participants were driving an average of 614 km and 9.4 h a day. Of the total samples, 5.2% (n = 40) tested positive for drugs. Cocaine was the most frequently found drug (n = 21), followed by amphetamine (n = 16) and D9-THC (n = 8). All drivers were men with an average age of 42.5 years. With these results we were able to verify that many truck drivers were still consuming psychoactive drugs while driving, and cocaine was the most prevalent one. This reinforces the need for preventive measures aimed at controlling the use of illicit drugs by truck drivers in Brazil.
- Determination of cocaine, metabolites and a crack cocaine biomarker in whole blood by liquid-liquid extraction and UHPLC-MS/MS(2018) TAKITANE, Juliana; LEYTON, Vilma; ANDREUCCETTI, Gabriel; GJERDE, Hallvard; VINDENES, Vigdis; BERG, ThomasCocaine is a potent stimulant drug widely abused that exists in two forms: as a hydrochloride salt and as a free base (crack). Cocaine and the inactive metabolite benzoylecgonine can be determined to reveal any kind of cocaine use, whereas the pyrolysis product anhydroecgonine methyl ester (AEME) can be determined to reveal crack smoking. There are many bioanalytical LC-MS/MS methods used for the determination of cocaine, metabolites and AEME. In these methods, chromatographic separation is usually performed by HPLC and sample preparation by solid phase extraction. For the first time, an UHPLC-MS/MS method for the simultaneous determination of cocaine, benzoylecgonine, cocaethylene and AEME in blood using a sample preparation by liquid-liquid extraction was developed and validated. Extraction recoveries were approximately 80%, 40%, 80% and 80%, respectively, obtained by using a mixture of MTBE/2-propanol (70: 30, v: v). Chromatographic separation was performed on a core shell biphenyl UHPLC column (100 x 2.1 mm ID, 1.7 mm particles). Method validation showed that the method is precise, accurate, robust and sensitive for its purposes. Limit of quantification (LOQ) concentrations were 0.7-1.5 ng/mL. The method was used to determine cocaine, benzoylecgonine, cocaethylene and AEME in 22 blood samples collected from victims of sudden, unexpected or violent death in Sao Paulo (Brazil). Concentrations >= LOQ were observed in 19, 21, 10 and 10 of these samples, respectively.
- The effect of sodium fluoride preservative and storage temperature on the stability of cocaine in horse blood, sheep vitreous and deer muscle(2012) REES, Kelly A.; JONES, Nicola S.; MCLAUGHLIN, Poppy A.; SEULIN, Saskia; LEYTON, Vilma; YONAMINE, Mauricio; OSSELTON, M. DavidThe in vitro stability of cocaine in horse blood, sheep vitreous humour (VH) and homogenised deer muscle is described. The stability of cocaine in horse blood was of interest because many toxicology laboratories utilise horse blood for the preparation of calibration and check standards and the latter are typically stored during routine use. The storage stability of cocaine in human VH and muscle has not been previously reported. In the absence of blank human VH and muscle, cocaine stability under varying conditions was demonstrated in animal tissues. Blood and VH were stored with and without addition of NaF at room temperature (RT), 4 degrees C and -18 degrees C for 84 days. Muscle homogenates were prepared in water, water/2% NaF, and phosphate buffer (pH 6.0)/2% NaF, and stored for 31 days at RT, 4 degrees C and -18 degrees C. Cocaine stability in human muscle obtained from cocaine positive forensic cases was assessed following storage at -18 degrees C for 13 months. Cocaine and benzoylecgonine (BZE) were extracted using SPE and quantified by GC-MS/MS. Cocaine was stable for 7 days in refrigerated (4 degrees C) horse blood fortified with 1 and 2% NaF. In the absence of NaF, cocaine was not detectable by day 7 in blood stored at RT and 4 degrees C and had declined by 81% following storage at -18 degrees C. At 4 degrees C the rate of cocaine degradation in blood preserved with 2% NaF was significantly slower than with 1% NaF. The stability of cocaine in horse blood appeared to be less than that reported for human blood, probably attributable to the presence of carboxylesterase in horse plasma. Cocaine stored in VH at -18 degrees C was essentially stable for the study period whereas at 4 degrees C concentrations decreased by >50% in preserved and unpreserved VH stored for longer than 14 days. Fluoride did not significantly affect cocaine stability in VH. The stability of cocaine in muscle tissue homogenates significantly exceeded that in blood and VH at every temperature. In preserved and unpreserved samples stored at 4 degrees C and below, cocaine loss did not exceed 2%. The increased stability of cocaine in muscle was attributed to the low initial pH of post-mortem muscle. In tissue from one human case stored for 13 months at -18 degrees C the muscle cocaine concentration declined by only 15% (range: 5-22%). These findings promote the use of human muscle as a toxicological specimen in which cocaine may be detected for longer compared with blood or VH.
- SNPs from BCHE and DRD3 genes associated to cocaine abuse amongst violent individuals from Sao Paulo, Brazil(2020) PEGO, A.M.F.; LEYTON, V.; MIZIARA, I.D.; BORTOLIN, R.H.; FREITAS, R.C.C.; HIRATA, M.; TOMAZ, P.R.X.; SANTOS, J.R.; SANTOS, P.C.J.L.; YONAMINE, M.Violence and drug abuse are highly destructive phenomena found world-wide, especially in Brazil. They seem to rise proportionally to one another and possibly related. Additionally, genetics may also play a role in drug abuse. This study has focused on identifying the use of cocaine within postmortem cases arriving at the Institute of Legal Medicine of Sao Paulo as well as the presence of certain single nucleotide polymorphisms (SNPs) to better understand one's susceptibility to abuse the drug. Both hair and blood samples have been extracted through a simple methanol overnight incubation or a rapid dilute-and-shoot method, respectively. The samples were then analyzed using an UPLC-ESI-MS/MS and genotyped through RT-PCR. Statistical analyses were performed via SPSS software. From 105 postmortem cases, 53% and 51% of the cases shown to be positive for cocaine in hair and blood, respectively. Genetic wise, a significant difference has been observed for SNP rs4263329 from the BCHE gene with higher frequencies of the genotypes A/G and G/G seen in cocaine users (OR = 8.91; 95%CI = 1.58–50.21; p = 0.01). Likewise, also SNP rs6280 from the DRD3 gene presented a significant association, with both genotypes T/C and C/C being more frequent in users (OR = 4.96; 95% CI = 1.07–23.02; p = 0.04). To conclude, a rather high proportion of cocaine has been found, which may suggest a connotation between the use of the drug and risky/violent behaviors. Additionally, significant associations were also found within two SNPs related to cocaine use, however, due to several inherent limitations, these must be confirmed. © 2020 Elsevier B.V.
- Analysis of skeletal muscle has potential value in the assessment of cocainerelated deaths(2013) REES, Kelly A.; SEULIN, Saskia; YONAMINE, Mauricio; LEYTON, Vilma; MUNOZ, Daniel R.; GIANVECCHIO, Victor A. P.; POUNDER, Derrick J.; OSSELTON, M. DavidThis study assesses the interpretive value of cocaine, benzoylecgonine (BZE) and cocaethylene (COET) in skeletal muscle (rectus femoris) in cocaine-using decedents. The distribution of these analytes in cardiac muscle (CM), vitreous humour (VH), femoral blood (FB) and cardiac blood (CB) is also reported. In rectus femoris muscle, the spatial distribution of the analytes was examined across the whole rectus femoris muscle collected from seven fatalities in which cocaine was detected. In six of these cases, death was attributed to trauma and in one case the cause of death was undetermined but suspected to be drug related. In two additional cases analytes were detected in the blood and/or VH but not in the muscle. The muscle was sectioned into 12-15 approximately equal segments, each of which was analysed after homogenisation. Tissue and bio-fluid samples were extracted by solid phase extraction with confirmation and quantification by GC-ion trap-MS/MS. No significant variation was observed in the concentration of any analyte throughout the muscle in the 7 cases analysed. The results reported here are in contrast to a previous study in which great variation in the concentration of some basic drugs (mainly tricyclic antidepressants and benzodiazepines) was observed throughout the thigh muscle bulk (Williams and Pounder, 1997). Analyte concentrations in skeletal muscle (SM) correlated well with those in FB (p < 0.01). In general, the concentration of cocaine and COET followed the order VH > CM > SM > FB >= CB. Cocaine concentrations measured in VH were significantly higher than in blood and muscle. Inter-matrix variations in the concentrations of BZE and COET were less marked. The concentration of BZE exceeded that of cocaine in all matrices and in all cases except one where the time between death and drug intake was suspected to be short. In this case, the cocaine to BZE ratio measured in SM (2.66), CM (2.91) and VH (2.19) was higher than that measured in FB (0.97). Given that the concentrations of cocaine and its metabolites were uniformly distributed throughout the muscle and considering the good correlation observed between muscle and blood, muscle could be of interpretive value in cocaine related deaths. Further, since cocaine is known to have greater post-mortem stability in muscle than blood, concentrations measured in muscle may reflect more closely those at the time of death and might be of particular value in cases with an extended period between death and tissue sampling.