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1.
Food Chem ; 327: 127013, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454275

RESUMO

As a subtropical fruit with high commercial values, litchi is also a source of methylenecyclcopropylglycine (MCPG) and hypoglycin A (HGA), which could cause hypoglycemia and fatal encephalopathy in human. In this work, a quantitative method was developed well to detect MCPG and HGA present in litchi aril of different cultivars. Method validation was evaluated well by linearity, recovery, precision and sensitivity. Among three cultivars, 'Feizixiao' contained the highest toxin level with 0.60-0.83 mg kg-1 of MCPG and 10.66-14.46 mg kg-1 of HGA, followed by 'Huaizhi' with 0.08-0.12 mg kg-1 of MCPG and 0.63-1.54 mg kg-1 of HGA, and 'Nuomici' with 0.09-0.11 mg kg-1 of MCPG and 0.35-0.91 mg kg-1 of HGA. The toxin levels were highly associated with litchi cultivar and storage time. These findings can provide new knowledge to help to recommend the safe consumption of fresh litchi based on human health.


Assuntos
Ciclopropanos/análise , Análise de Alimentos/métodos , Glicina/análogos & derivados , Hipoglicinas/análise , Litchi/química , China , Cromatografia Líquida de Alta Pressão , Frutas/química , Glicina/análise , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
2.
J Chromatogr A ; 1622: 461103, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32317104

RESUMO

Triacylglycerols (TAGs) containing cyclofatty acids (cycloFAs) from two oilseeds of Sterculia foetida and Hydnocarpus wightiana were analysed using both reversed-phase (RP18) and chiral phase columns. TAGs were identified using high-resolution electrospray ionization mass spectrometry in the positive ion mode. Fifty-five molecular species of TAGs have been identified in sterculic oil, 27 of which contained at least one cyclopropenyl-FA (e.g., malvalic or sterculic acids). The structures of regioisomers and enantiomers were determined for five major TAGs with cyclopropenyl-FAs. One hundred thirty-six TAGs were identified in chaulmoogra oil, 71 of which contained at least one cyclopentenyl-FA (e.g., gorlic, chaulmoogric, and hydnocarpic acids, etc.). Furthermore, in three molecular species, regioisomers and enantiomers were identified using HPLC on a chiral phase column. Eight molecular species of TAGs were prepared through organic synthesis to facilitate the identification of enantiomers. Retention times of fatty acid-containing triacylglycerols with one ring and one double bond are very similar to triacylglycerols with a dienoic fatty acid, but elution times are shorter. For example, dimalvaloylpalmitate elutes earlier than dilinoleylpalmitate. The order of elution of TAGs on the chiral column differs. In TAGs with 2 degrees of unsaturation (ring and double bond, e.g. PStP-StPP-PPSt), the order of elution is symmetric-asymmetric-asymmetric TAGs. TAGs with 4 degrees of unsaturation (one ring and three double bonds or two rings and two double bonds) present a different pattern. When TAGs contain two rings and two double bonds, the order of elution TAGs is asymmetric-symmetric-asymmetric (StStP-StPSt-PStSt); when TAGs contain a ring and 3 double bonds, the elution order is symmetric-asymmetric-asymmetric TAGs (OStO-StOO-OOSt). In species with a higher degree of unsaturation (e.g., 5), the elution order of the TAGs is asymmetric-asymmetric-symmetric (e.g. CCO-OCC-COC).


Assuntos
Ácidos Graxos/análise , Triglicerídeos/química , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Ciclopropanos/análise , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Ácidos Graxos Monoinsaturados/análise , Óleos Vegetais/química , Espectrometria de Massas por Ionização por Electrospray , Sterculia/química , Estereoisomerismo
3.
Int J Food Sci Nutr ; 70(4): 467-473, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30451036

RESUMO

Cyclopropane fatty acids (CPFAs) are the most abundant cyclic fatty acids in microorganisms with unknown role(s) regarding their dietary relevance and biological effects in humans. This work was aimed to draw up a list of CPFAs-containing foods for estimating their dietary intake in the Italian population to provide a basis for evaluating their nutritional relevance and potential health-related effects. The CPFAs content of more than 500 food items was investigated and a preliminary dietary intake was assessed (12.0 ± 6.0 mg/day), based on the data reported by the Italian National Food Consumption Survey INRAN-SCAI 2005-06. CPFAs should be considered of dietary relevance in view of their potential physiological activity in humans and their presence in significant amounts in dairy products, as Grana Padano cheese (9.0-30.0 mg/100 g), and in bovine meat (0.7-4.0 mg/100 g). Future studies should elucidate whether this uncommon class of fatty acids has a biological role in human health.


Assuntos
Ciclopropanos/análise , Dieta , Ácidos Graxos/análise , Queijo , Laticínios , Humanos , Itália , Rhizophoraceae
4.
Analyst ; 144(3): 901-912, 2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30207333

RESUMO

Cyclopropane fatty acids (CFAs) are a group of lipids with unique physical and chemical properties between those of saturated and monounsaturated fatty acids. The distinctive physicochemical characteristics of CFAs (e.g. oxidative stability, self-polymerization at high temperatures, etc.) results from the presence of a cyclopropane ring within their structure making them highly useful in industrial applications. CFAs are present in several species of plants and bacteria and are typically detected with standard lipid profiling techniques, such as gas or liquid chromatography. In this work we investigated several strains of S. cerevisiae, genetically modified to introduce the production of CFAs, in comparison to control strain using confocal Raman spectroscopy (CRS). The aim of our work was to demonstrate the potential of CRS not only to detect changes introduced due to the CFAs presence, but also to track CFAs within the cells. We present for the first time Raman and IR spectra of CFA standard (cis-9,10-methyleneoctadecanoic acid), completed with quantum chemical calculations and band assignment. We identified marker bands of CFA (e.g. 2992, 1222, 942 cm-1) attributed to the vibrations of the cyclopropyl ring. Furthermore, we analysed lipid bodies (LBs) from modified and control yeast using CRS imaging and identified multiple changes in size, number and composition of LBs from engineered strains. We observed a significant reduction in the degree of unsaturation of LBs using the ratio of bands located at 1660 cm-1 (ν(C[double bond, length as m-dash]C)) and 1448 cm-1 (δ(CH2)) in the modified cell lines. In addition, we were able to detect the presence of CFAs in LBs, using the established marker bands. CRS shows tremendous potential as technique to identify CFAs in lipid bodies providing a new way to track lipid production in genetically modified single yeast cells.


Assuntos
Rastreamento de Células/métodos , Ciclopropanos/análise , Ácidos Graxos/análise , Engenharia Genética/métodos , Saccharomyces cerevisiae/metabolismo , Análise Espectral Raman/métodos , Ciclopropanos/metabolismo , Ácidos Graxos/metabolismo , Saccharomyces cerevisiae/genética
5.
J Chromatogr A ; 1573: 156-160, 2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30224281

RESUMO

A rapid thermal desorption-gas chromatography-electron ionization-mass spectrometry (TD-GC-EI-MS) method for airborne transfluthrin detection is studied. Active air sampling of 9 L over 1 h at 23 °C through a Tenax®-loaded tube resulted in efficient capture of airborne transfluthrin. Subsequent thermal desorption was employed to achieve an LOD of 2.6 ppqv (parts per quadrillion by volume). A minimum primary desorption temperature of 300 °C is necessary for optimal recovery of sample from the Tenax® adsorbent. The matrix effects of indoor air lead to an error of 10.9% and 10.5% recovery of sample (10 pg and 100 pg loaded tubes, respectively). The linear range was 74-74,000 ppqv with a correlation coefficient of 0.9981. Active air sampling of a novel passive release device revealed a ∼150 pg/L airborne concentration gradient over 1 m, providing spatial characterization of the device's performance. This efficient method allows for the remote collection of samples and rapid analysis of airborne transfluthrin from industrial applications, optimization studies of commercial products as well as domestic/household monitoring.


Assuntos
Poluentes Atmosféricos/análise , Ciclopropanos/análise , Monitoramento Ambiental/métodos , Fluorbenzenos/análise , Cromatografia Gasosa-Espectrometria de Massas , Monitoramento Ambiental/instrumentação , Polímeros/química
6.
Food Chem ; 264: 449-454, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29853400

RESUMO

Methylenecyclcopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in various soapberry (Sapindaceae) fruits. These toxins have been linked to illnesses worldwide and were recently implicated in Asian outbreaks of acute hypoglycemic encephalopathy. In a previous joint agricultural and public health investigation, we developed an analytical method capable of evaluating MCPG and HGA concentrations in soapberry fruit arils as well as a clinical method for the urinary metabolites of the toxins. Since the initial soapberry method only analyzed the aril portion of the fruit, we present here the extension of the method to include the fruit seed matrix. This work is the first method to quantitate both MCPG and HGA concentrations in the seeds of soapberry fruit, including those collected during a public health investigation. Further, this is the first quantitation of HGA in litchi seeds as well as both toxins in mamoncillo and longan seeds.


Assuntos
Cromatografia Líquida de Alta Pressão , Ciclopropanos/análise , Glicina/análogos & derivados , Hipoglicinas/análise , Sapindus/metabolismo , Espectrometria de Massas em Tandem , Frutas/química , Frutas/metabolismo , Glicina/análise , Sementes/metabolismo
7.
Rapid Commun Mass Spectrom ; 31(19): 1573-1581, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28708331

RESUMO

RATIONALE: Transfluthrin is a relatively non-toxic rapid-acting synthetic pyrethroid insecticide. It is widely used in household and hygiene products. A sensitive and accurate bioanalytical method is required for quantification of its concentration in plasma and its potential target organ, the brain for studies to assess its health effects and toxicokinetics in mammals. METHODS: The samples were prepared by liquid-liquid extraction. Gas chromatography mass spectrometry (GC/MS) analysis was performed for the determination of transfluthrin in biological samples with an overall method run time of 15 min. Transfluthrin was quantified using selected-ion monitoring (SIM) in the negative chemical ionization (NCI) mode. Chromatographic separation was achieved using a Zebron® ZB5-MS GC column operating with 1 mL/min constant flow helium. Cis-Permethrin was used as the internal standard. RESULTS: The method was validated to be precise and accurate within the linear range of 1.0-400.0 ng/mL in plasma and 4.0-400.0 ng/mL in brain homogenate, based on a 100 µL sample volume for both matrices. This method was applied to samples following administration of a 10 mg/kg oral dose to male adult rats. The plasma concentrations were observed to be 11.70 ± 5.69 ng/mL and brain concentrations 12.09 ± 3.15 ng/g when measured 2 h post-dose. CONCLUSIONS: A rapid GC/NCI-MS method was demonstrated to be sensitive, specific, precise and accurate for the quantification of transfluthrin in rat plasma and brain. The optimized method was successfully used to quantify the rat plasma and brain concentrations of transfluthrin 2 h after the oral dosing of Sprague-Dawley rats.


Assuntos
Química Encefálica , Ciclopropanos/análise , Ciclopropanos/sangue , Fluorbenzenos/análise , Fluorbenzenos/sangue , Cromatografia Gasosa-Espectrometria de Massas/métodos , Inseticidas/análise , Inseticidas/sangue , Administração Oral , Animais , Ciclopropanos/administração & dosagem , Fluorbenzenos/administração & dosagem , Cromatografia Gasosa-Espectrometria de Massas/economia , Inseticidas/administração & dosagem , Extração Líquido-Líquido/economia , Extração Líquido-Líquido/métodos , Masculino , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes
8.
Ecotoxicology ; 26(7): 876-888, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28560497

RESUMO

The transport of agricultural insecticides to water bodies may create risk of exposure to non-target organisms. Similarly, widespread use of furrow-applied and seed-coated insecticides may increase risk of exposure, yet accessible exposure models are not easily adapted for furrow application, and only a few examples of model validation of furrow-applied insecticides exist using actual field data. The goal of the current project was to apply an exposure model, the Pesticide in Water Calculator (PWC), to estimate the concentrations of two in-furrow insecticides applied to maize: the granular pyrethroid, tefluthrin, and the seed-coated neonicotinoid, clothianidin. The concentrations of tefluthrin and clothianidin in surface runoff water, sampled from a field in central Illinois (USA), were compared to the PWC modeled pesticide concentrations in surface runoff. The tefluthrin concentrations were used to optimize the application method in the PWC, and the addition of particulate matter and guttation droplets improved the models prediction of clothianidin concentrations. Next, the tefluthrin and clothianidin concentrations were calculated for a standard farm pond using both the optimized application method and the application methods provided in PWC. Estimated concentrations in a standard farm pond varied by a factor of 100 for tefluthrin and 50 for clothianidin depending on the application method used. The addition of guttation droplets and particulate matter to the model increased the annual clothianidin concentration in a standard farm pond by a factor of 1.5, which suggested that these transport routes should also be considered when assessing neonicotinoid exposure.


Assuntos
Ciclopropanos/análise , Monitoramento Ambiental , Guanidinas/análise , Hidrocarbonetos Fluorados/análise , Inseticidas/análise , Neonicotinoides/análise , Poluentes do Solo/análise , Tiazóis/análise , Modelos Químicos , Sementes/química
9.
Microb Pathog ; 108: 13-20, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28455137

RESUMO

We have been interested, in this work, to investigate the effect of the exposure to static magnetic field at 200 mT (SMF) on the fatty acid (FA) composition of Salmonella enterica subsp Enterica serovar Hadar isolate 287: effects on the proportion of saturated and unsaturated fatty acids (SFAs, UFAs), cyclopropane fatty acids (CFAs) and hydroxy fatty acids after exposure to the static magnetic field at 200 mT (SMF). Analysis with Gas Chromatography-Mass Spectrometry (GC-MS) of total lipid showed that the proportion of the most fatty acids was clearly affected. The comparison of UFAs/SFAs ratio in exposed bacteria and controls showed a diminution after 3 and 6 h of exposure. This ration reached a balance after 9 h of treatment with SMF. So we can conclude that S. Hadar tries to adapt to magnetic stress by changing the proportions of SFAs and UFAs over time to maintain an equilibrium after 9 h of exposure, thus to maintain the inner membranes fluidity. Also, a decrease in the proportion of hydroxy FAs was observed after 6 h but an increase of this proportion after 9 h of exposure. Concerning CFAs, its proportion raised after 6 h of exposure to the SMF but it decreased after 9 h of exposure. These results are strongly correlated with those of cfa (cyclopropane fatty acid synthase) gene expression which showed a decrease of its expression after 9 h of exposure.


Assuntos
Ácidos Graxos/análise , Campos Magnéticos , Salmonella enterica/metabolismo , Salmonella enterica/efeitos da radiação , Ciclopropanos/análise , Ciclopropanos/química , Ácidos Graxos/química , Ácidos Graxos/genética , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/genética , Cromatografia Gasosa-Espectrometria de Massas , Regulação Bacteriana da Expressão Gênica/efeitos da radiação , Fluidez de Membrana/efeitos da radiação , Lipídeos de Membrana , Metiltransferases/genética , Metiltransferases/efeitos da radiação , RNA Bacteriano/análise , RNA Ribossômico 16S/genética , Salmonella enterica/genética , Fatores de Tempo
10.
Lancet Glob Health ; 5(4): e458-e466, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28153514

RESUMO

BACKGROUND: Outbreaks of unexplained illness frequently remain under-investigated. In India, outbreaks of an acute neurological illness with high mortality among children occur annually in Muzaffarpur, the country's largest litchi cultivation region. In 2014, we aimed to investigate the cause and risk factors for this illness. METHODS: In this hospital-based surveillance and nested age-matched case-control study, we did laboratory investigations to assess potential infectious and non-infectious causes of this acute neurological illness. Cases were children aged 15 years or younger who were admitted to two hospitals in Muzaffarpur with new-onset seizures or altered sensorium. Age-matched controls were residents of Muzaffarpur who were admitted to the same two hospitals for a non-neurologic illness within seven days of the date of admission of the case. Clinical specimens (blood, cerebrospinal fluid, and urine) and environmental specimens (litchis) were tested for evidence of infectious pathogens, pesticides, toxic metals, and other non-infectious causes, including presence of hypoglycin A or methylenecyclopropylglycine (MCPG), naturally-occurring fruit-based toxins that cause hypoglycaemia and metabolic derangement. Matched and unmatched (controlling for age) bivariate analyses were done and risk factors for illness were expressed as matched odds ratios and odds ratios (unmatched analyses). FINDINGS: Between May 26, and July 17, 2014, 390 patients meeting the case definition were admitted to the two referral hospitals in Muzaffarpur, of whom 122 (31%) died. On admission, 204 (62%) of 327 had blood glucose concentration of 70 mg/dL or less. 104 cases were compared with 104 age-matched hospital controls. Litchi consumption (matched odds ratio [mOR] 9·6 [95% CI 3·6 - 24]) and absence of an evening meal (2·2 [1·2-4·3]) in the 24 h preceding illness onset were associated with illness. The absence of an evening meal significantly modified the effect of eating litchis on illness (odds ratio [OR] 7·8 [95% CI 3·3-18·8], without evening meal; OR 3·6 [1·1-11·1] with an evening meal). Tests for infectious agents and pesticides were negative. Metabolites of hypoglycin A, MCPG, or both were detected in 48 [66%] of 73 urine specimens from case-patients and none from 15 controls; 72 (90%) of 80 case-patient specimens had abnormal plasma acylcarnitine profiles, consistent with severe disruption of fatty acid metabolism. In 36 litchi arils tested from Muzaffarpur, hypoglycin A concentrations ranged from 12·4 µg/g to 152·0 µg/g and MCPG ranged from 44·9 µg/g to 220·0 µg/g. INTERPRETATION: Our investigation suggests an outbreak of acute encephalopathy in Muzaffarpur associated with both hypoglycin A and MCPG toxicity. To prevent illness and reduce mortality in the region, we recommended minimising litchi consumption, ensuring receipt of an evening meal and implementing rapid glucose correction for suspected illness. A comprehensive investigative approach in Muzaffarpur led to timely public health recommendations, underscoring the importance of using systematic methods in other unexplained illness outbreaks. FUNDING: US Centers for Disease Control and Prevention.


Assuntos
Encefalopatia Aguda Febril/diagnóstico , Surtos de Doenças/estatística & dados numéricos , Frutas/toxicidade , Litchi/toxicidade , Síndromes Neurotóxicas/diagnóstico , Encefalopatia Aguda Febril/epidemiologia , Encefalopatia Aguda Febril/etiologia , Adolescente , Estudos de Casos e Controles , Criança , Ciclopropanos/análise , Feminino , Glicina/análogos & derivados , Glicina/análise , Humanos , Hipoglicinas/análise , Índia , Masculino , Síndromes Neurotóxicas/epidemiologia , Síndromes Neurotóxicas/etiologia , Razão de Chances
11.
J Agric Food Chem ; 64(27): 5607-13, 2016 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-27367968

RESUMO

Methylenecyclopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in some soapberry fruits. Fatalities have been reported worldwide as a result of HGA ingestion, and exposure to MCPG has been implicated recently in the Asian outbreaks of hypoglycemic encephalopathy. In response to an outbreak linked to soapberry ingestion, the authors developed the first method to simultaneously quantify MCPG and HGA in soapberry fruits from 1 to 10 000 ppm of both toxins in dried fruit aril. Further, this is the first report of HGA in litchi, longan, and mamoncillo arils. This method is presented to specifically address the laboratory needs of public-health investigators in the hypoglycemic encephalitis outbreaks linked to soapberry fruit ingestion.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Ciclopropanos/análise , Frutas/química , Glicina/análogos & derivados , Hipoglicinas/análise , Sapindaceae/química , Espectrometria de Massas em Tandem/métodos , Ciclopropanos/toxicidade , Frutas/toxicidade , Glicina/análise , Glicina/toxicidade , Hipoglicinas/toxicidade , Sapindaceae/toxicidade
12.
J Agric Food Chem ; 64(20): 4158-64, 2016 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-27133588

RESUMO

Cyclopropane fatty acids (CPFA), as lactobacillic acid and dihydrosterculic acid, are components of bacterial membranes and have been recently detected in milk and in dairy products from cows fed with corn silage. In this paper, a specific quantitative gas chromatography-mass spectrometry (GC-MS) method for the detection of CPFA in cheeses was developed, and the quality parameters of the method (limit of detection, limit of quantitation, and intralaboratory precision) were assessed. Limit of detection and quantitation of CPFA were, respectively, 60 and 200 mg/kg of cheese fat, and the intralaboratory precision, determined on three concentration levels, satisfied the Horwitz equation. This method was applied to 304 samples of PDO cheeses of certified origin, including Parmigiano Reggiano (Italy), Grana Padano (Italy), Fontina (Italy), Comté (France), and Gruyère (Switzerland). Results showed that CPFA were absent in all of the cheeses whose Production Specification Rules expressly forbid the use of silages (Parmigiano Reggiano, Fontina, Comté, and Gruyère). CPFA were instead present in variable concentrations (300-830 mg/kg of fat) in all of the samples of Grana Padano cheese (silages admitted). A mix of grated Parmigiano Reggiano and Grana Padano was also prepared, showing that the method is able to detect the counterfeiting of Parmigiano Reggiano with other cheeses up to 10-20% Grana Padano content. These results support the hypothesis that CPFA can be used as a marker of silage feedings for cheeses, and the data reported can be considered a first attempt to create a database for CPFA presence in PDO cheeses.


Assuntos
Queijo/análise , Ciclopropanos/análise , Ácidos Graxos/análise , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Animais , Bovinos , Europa (Continente) , Silagem/análise
13.
Forensic Sci Int ; 249: 165-72, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25700112

RESUMO

Forensic toxicological drug analyses of human specimens are usually performed immediately after autopsy or on frozen preserved tissues. Occasionally, cases require analysis of drugs from tissues fixed in formalin solution. To improve the estimation of the level of drug in tissues following formalin fixation, we studied drug concentrations in human tissues, liver and kidney, that were collected from a drug-positive autopsy case. Parts of tissues were preserved in formalin solution for 1, 3, 6 and 13 months. Tissues obtained before and after preservation, along with tissue-exposed fixatives, were assayed using gas chromatography-mass spectrometry; all of the samples were assayed for the presence of drugs and changes in the drug concentrations both before and after preservation in formalin. Concentrations of assayed drugs decreased upon fixation in formalin; levels of these drugs did not necessarily show further decreases during subsequent storage in fixative, up to 13 months. Distinct trends in drug levels were found in liver and kidney. In liver, the levels of chlorpromazine, levomepromazine, and promethazine decreased to 23-39% at 1 month after preservation; all 3 of these drugs were detected at all tested time points of preservation. Bromazepam was not detected at 13 months after preservation. Milnacipran was the most unstable after preservation in formalin solution among all of the assayed drugs. In kidney, all assayed drugs exhibited reduced stability during preservation compared to levels in liver. Methamphetamine and methylenedioxymethamphetamine were not detected in any time points of tissues. The proportions of the drugs that remained within the tissues differed between liver and kidney. Also, S-oxide compounds of chlorpromazine and levomepromazine, which were not observed before preservation, were detected in fixed liver tissues and their fixatives at 3, 6 and 13 months of preservation. These results suggest that analyses in formalin-fixed tissues need to include analysis of various organ-tissues and their fixatives at multiple time points for the duration of preservation. These analyses should include detection of chemical degradation/denaturation products, such as S-oxides of chlorpromazine and levomepromazine.


Assuntos
Antipsicóticos/análise , Fixadores , Formaldeído , Rim/química , Fígado/química , Entorpecentes/análise , Preservação de Órgãos/métodos , Adulto , Bromazepam/análise , Clorpromazina/análise , Ciclopropanos/análise , Estabilidade de Medicamentos , Toxicologia Forense , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Metanfetamina/análise , Metotrimeprazina/análise , Milnaciprano , N-Metil-3,4-Metilenodioxianfetamina/análise , Prometazina/análise , Fatores de Tempo
14.
Food Sci Technol Int ; 21(3): 175-87, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24495994

RESUMO

The effects of 1-methylcyclopropene (1-MCP) on shelf life, fruit visual quality and nutritional quality were investigated. Netted melons were treated with air (control) and 0.6 µl l(-1) 1-MCP at 25 ℃ for 24 h, and then stored at 25 ℃ or 10 ℃ for 10 days. 1-MCP significantly extended the shelf life, inhibited weight loss and delayed firmness decline of melon fruits. Ethylene production was also inhibited and respiration rate was declined. 1-MCP retarded 1-aminocyclopropane-1-carboxylic acid (ACC) increases and inhibited ACC synthase and ACC oxidase activity. Moreover, 1-MCP treatment reduced the decrease in total soluble solids and titratable acidity, as well as the decrease of the content of sugars (sucrose, fructose and glucose). These results indicated that 1-MCP treatment is a good method to extend melon shelf life and maintain fruit quality, and the combination of 1-MCP and low temperature storage resulted in more acceptable fruit quality.


Assuntos
Cucurbitaceae , Ciclopropanos/análise , Conservantes de Alimentos/análise , Qualidade dos Alimentos , Aminoácido Oxirredutases/antagonistas & inibidores , Aminoácido Oxirredutases/metabolismo , Aminoácidos Cíclicos/metabolismo , Temperatura Baixa , Etilenos/metabolismo , Armazenamento de Alimentos , Frutose/análise , Frutas , Glucose/análise , Liases/antagonistas & inibidores , Liases/metabolismo , Sacarose/análise
15.
Methods Mol Biol ; 1183: 253-61, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25023314

RESUMO

In order to explore the possibility of identifying toxins based on their effect on the shape of action potentials, we created a computer model of the action potential generation in NG108-15 cells (a neuroblastoma/glioma hybrid cell line). To generate the experimental data for model validation, voltage-dependent sodium, potassium and high-threshold calcium currents, as well as action potentials, were recorded from NG108-15 cells with conventional whole-cell patch-clamp methods. Based on the classic Hodgkin-Huxley formalism and the linear thermodynamic description of the rate constants, ion-channel parameters were estimated using an automatic fitting method. Utilizing the established parameters, action potentials were generated using the Hodgkin-Huxley formalism and were fitted to the recorded action potentials. To demonstrate the applicability of the method for toxin detection and discrimination, the effect of tetrodotoxin (a sodium channel blocker) and tefluthrin (a pyrethroid that is a sodium channel opener) were studied. The two toxins affected the shape of the action potentials differently, and their respective effects were identified based on the predicted changes in the fitted parameters.


Assuntos
Potenciais de Ação , Simulação por Computador , Modelos Neurológicos , Potenciais de Ação/efeitos dos fármacos , Animais , Técnicas de Cultura de Células/métodos , Linhagem Celular Tumoral , Ciclopropanos/análise , Ciclopropanos/farmacologia , Hidrocarbonetos Fluorados/análise , Hidrocarbonetos Fluorados/farmacologia , Canais Iônicos/metabolismo , Técnicas de Patch-Clamp/métodos , Agonistas de Canais de Sódio/análise , Agonistas de Canais de Sódio/farmacologia , Bloqueadores dos Canais de Sódio/análise , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/farmacologia , Termodinâmica
16.
J Agric Food Chem ; 62(31): 7828-32, 2014 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-25033416

RESUMO

A survey was carried out to determine the presence of cyclopropane fatty acids (CPFA) in various dairy products. CPFA such as lactobacillic acid and dihydrosterculic acid are components of bacterial membranes and have been recently detected in milk from cows fed with maize silage. In this paper about 200 dairy samples comprising cow, sheep, and goat milk, cheese, yogurt/fermented milk, and butter were analyzed. Results showed that cow milks were generally positive to CPFA (0.014-0.105% of total fatty acids), while goat, yak, and sheep milks were negative. Experimental yogurt and fermented milks showed the same CPFA content of the starting milk. Positive to CPFA were also the majority of samples of commercial butter and cheeses, except some PDO cheeses as Parmigiano-Reggiano and Fontina, cheeses from mountain regions, and goat and sheep cheeses. These data suggest that the presence of CPFA in dairy products could be used as a marker of silage feeding.


Assuntos
Ciclopropanos/análise , Laticínios/análise , Ácidos Graxos/análise , Leite/química , Ração Animal , Animais , Bactérias/química , Bactérias/ultraestrutura , Manteiga/análise , Bovinos , Parede Celular/química , Queijo/análise , Fermentação , Cromatografia Gasosa-Espectrometria de Massas , Cabras , Lactobacillus/metabolismo , Lactobacillus/ultraestrutura , Ovinos
17.
J Mass Spectrom ; 49(3): 201-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24619546

RESUMO

The structures of phosphatidylethanolamine (PE) in Leishmania infantum are unique in that they consist of a rare cyclopropane fatty acid (CFA) containing PE subfamily, including CFA-containing plasmalogen PE species. In this contribution, we applied multiple-stage linear ion-trap combined with high-resolution mass spectrometry to define the structures of PEs that were desorbed as [M - H](-) and [M - H + 2Li](+) ions by ESI, respectively. The structural information arising from MS(n) on both the molecular species are complimentary, permitting complete determination of PE structures, including the identities of the fatty acid substituents and their location on the glycerol backbone, more importantly, the positions of the double bond(s) and of the cyclopropane chain of the fatty acid chain, directing to the realization of the CFA biosynthesis pathways that were reported previously. We also uncovered the presence of a minor dimethyl-PE subclass that has not been previously reported in L. infantum. This LIT MS(n) mass spectrometric approach led to unambiguous identification of PE molecules including many isomers in complex mixture that would otherwise be very difficult to define using other analytical approaches.


Assuntos
Ciclopropanos/análise , Ciclopropanos/química , Leishmania infantum/química , Espectrometria de Massas/métodos , Fosfatidiletanolaminas/análise , Fosfatidiletanolaminas/química
18.
Mycotoxin Res ; 30(2): 61-70, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24504633

RESUMO

Stenocarpella maydis causes a fungal dry-rot of maize ears and is associated with diplodiosis, a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. There have been no reports of Stenocarpella metabolites in maize crop residues. Chemical investigations of S. maydis-infected grain from ears exhibiting different levels of ear rot severity following a 2010 field outbreak of Stenocarpella ear rot in Illinois led to the detection of diplodiatoxin and chaetoglobosins M and O as major components in the ethyl acetate extracts by LC-MS. Following post-harvest moist incubation of the S. maydis-infected grain, the amounts of each compound increased (approx. tenfold) and chaetoglobosin K was detected as a dominant toxin. In separate (1)H NMR-based analyses, the neurotoxin diplonine was detected as a minor component in methanol extracts of S. maydis-infected grain as well as cultures of S. maydis isolates from Midwest corn. Proline betaine (=stachydrine) and glycine betaine were also detected in these extracts as major components. This constitutes the first report of chaetoglobosin M, chaetoglobosin O, proline betaine, or glycine betaine from S. maydis, and the first record of diplodiatoxin, diplonine, proline betaine, glycine betaine, or chaetoglobosins M, O, or K being associated with a natural field outreak of S. maydis ear rot.


Assuntos
Ascomicetos/metabolismo , Cromonas/análise , Ciclopropanos/análise , Alcaloides Indólicos/análise , Doenças das Plantas/microbiologia , Zea mays/química , Zea mays/microbiologia , Ascomicetos/isolamento & purificação , Betaína/análise , Surtos de Doenças , Grão Comestível/química , Illinois , Espectroscopia de Ressonância Magnética , Micotoxinas/análise , Prolina/análogos & derivados , Prolina/análise
19.
J Chromatogr Sci ; 52(1): 42-51, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23258392

RESUMO

A simple, sensitive, precise and accurate stability-indicating ultra-performance liquid chromatography (UPLC) method was developed for the quantitative determination of the purity of the active pharmaceutical ingredient of milnacipran hydrochloride (MCP) and its pharmaceutical dosage form in the presence of its process-related impurities and degradation products. The proposed UPLC method utilizes Acquity UPLC BEH 100 mm, 2.1 mm and 1.7 µm phenyl columns at 27°C with a gradient program of 12.0 min at a flow rate of 0.5 mL/min. The compounds of interest were monitored at 210 nm. The resolution for MCP and 12 (potential byproducts and degradation) impurities was found to be greater than 2.0 for any pair of components. The high correlation coefficients (r(2) >0.9995) indicate clear correlations between the concentrations of investigated compounds and their peak areas. The relative standard deviations obtained for the repeatability and intermediate precision experiments were less than 5.0%. The accuracy of the method was further ascertained by performing recovery studies through spiking experiments. The drug substance was subjected to hydrolytic, oxidative, photolytic and thermal stress conditions, as per the International Conference on Harmonization (ICH). The developed method was validated according to the current ICH guidelines for specificity, limits of detection and quantitation, linearity, accuracy, precision, ruggedness and robustness. The method is also suitable for the assay determination of MCP in pharmaceutical dosage forms.


Assuntos
Ciclopropanos/análise , Ciclopropanos/química , Cromatografia Líquida , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Espectrometria de Massas , Milnaciprano , Reprodutibilidade dos Testes , Comprimidos/química
20.
Environ Int ; 60: 1-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23973617

RESUMO

Different household insecticide applications via two electric vaporizers emitting transfluthrin were realized in a full-scale experimental room under controlled air exchange rate conditions. On-line high-time resolved measurements of the gas-phase concentrations of the active substance during and immediately after the spreading periods were performed with a High Sensitivity Proton-Transfer-Reaction Mass Spectrometer (HS-PTR-MS). Experimental and modelled data from the ConsExpo 4.0 software were also compared to evaluate the sources of differences. Different application scenarios were also compared. Averaged inhaled concentrations over 1h, 1week, and 5months were estimated to be 8.3, 1.8, and 1.8µg.m(-3), respectively. Corresponding margins of exposures range from 1000 to 10,000, claiming for the absence of effect. Dermal and dust ingestion pathways, although roughly estimated, seems being non-negligible. This claims for a more in-depth integrated risk assessment.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Ciclopropanos/análise , Fluorbenzenos/análise , Exposição por Inalação/análise , Nebulizadores e Vaporizadores , Ar/análise , Gases/análise , Inseticidas , Modelos Químicos
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